Petro-SIM User Manual v6.0

User Manual Version 6.0 © Copyright KBC Advanced Technologies plc 2005-2015. All rights reserved. Intellectual Property Rights Software KBC Advanced Technologies plc ( KBC) is the owner of and has vested in it the copyright and all other intellectual property rights of a similar nature relating to its software, which includes, but is not limited to KBC's computer programs, user manuals, and all associated documentation, whether in printed or electronic form ( Software), which is supplied by KBC or its subsidiaries to their respective customers. No copying or reproduction of the Software shall be permitted without the prior written consent of KBC, save to the extent permitted by law. Portions of this product are based on HYSYS technology ©1998-2002 Hyprotech Company. Trademarks Petro-SIM, ALK-SIM, AROM-SIM, DC-SIM, DHTR-SIM, FCC-SIM, HCR-SIM, HTR-SIM, ISOM-SIM, OLEFIN-SIM, REF-SIM, RHDS-SIM, VIS-SIM, PETROFINE, KBC, and DISTOP are registered trademarks of KBC Advanced Technologies, plc in the United States and/or other countries. Microsoft Office, Microsoft Windows, Windows XP, Excel, and Visual Basic are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries. Sentinel RMS is a registered trademark of SafeNet, Inc. Multiflash is a registered trademark of Infochem Computer Services, Ltd. All other company names, products, or name brands are trademarks of their respective holders. Use The Licensee shall follow all instructions given to it by KBC from time to time in relation to the use of copyright, the KBC Trademarks, and all similar property rights in the Software, All rights in respect of KBC's Trademarks and all rights in respect of the copyright of the Software are reserved. The Licensee undertakes not to alter, obscure, remove, conceal, or otherwise interfere with KBC Trademarks or any indications of the source of the Software which may be placed on the Software or its packaging or any part thereof, or use, permit any party to use or authorize the use in any way whatsoever of trademarks that are similar or that may be confused with KBC Trademarks. KBC Advanced Technologies plc. KBC House, 42-50 Hersham Road Walton-on-Thames Surrey KT12 1RZ United Kingdom Website: www.kbcat.com Contents Chapter 1: Introduction to Petro-SIM 1 Petro-SIM Advantage 2 Petro-SIM Environments 3 Environment Relationships 4 Property View Flowsheet Analysis 11 Petro-SIM Refinery Assays 14 Variable Component Properties 14 Sub-Flowsheet Technology 14 Predictive Properties 15 Distillation Column Capabilities 15 KBC Advanced Technologies Expertise 15 Technical Support 16 Chapter 2: Petro-SIM Workspace 17 Workspace Basics 18 Petro-SIM Desktop 19 Navigator 20 Preview Pane 29 Object Status and Trace Windows 30 Change the Date and Time Format 33 Quick Access Toolbar Undo/Redo Working with the Ribbon Toolbar 36 37 38 Minimize the Ribbon 38 Dialog Box Launcher on the Ribbon 39 Tooltips 39 Keyboard Shortcuts 40 Ribbon Groups and Commands 43 File menu 44 Home tab 46 Time Series tab 49 Workflow Manager tab 51 iii Contents (continued) Data tab 53 Reports tab 55 Oil Characterization tab 57 PFD tab 59 Tools tab 63 Reactor/Calibration tab 65 Plot tab 68 Column tab 70 Dynamics tab 71 View tab 72 Legacy tab 74 Resources tab 75 Session Preferences 76 Simulation Tab 78 Display 105 Files 127 Chapter 3: Building a Simulation Simulation Case View 140 Main Tab 140 Licensing Tab 143 Case Oil Synthesis Settings 143 Managing Cases 145 Create a New Simulation Case 145 Open Cases 146 Save Cases 148 Templates 149 Printing in Petro-SIM 156 Screenshots 165 Email 165 Workspace 167 Close Cases and Exit Petro-SIM 169 Unit Operations iv 139 170 Unit Operation Property View 172 Solver Active or Hold 177 Contents (continued) Installing Operations 177 Setting Up Reactors in Petro-SIM 178 Chapter 4: Simulation Basis Environment Fluid Packages Fluid Package Property View Components 179 180 182 235 Component List View 237 Selecting Library Components 240 Add Hypothetical Components 243 Add Other Components 244 Manage the Selected Components List 244 Pure Component Property View 250 Hypotheticals 251 Create a Hypothetical 253 Tutorial: Adding a Hypothetical 277 Oil Manager 284 Reactions 284 Reaction Component Selection 285 Reactions 288 Reaction Sets 314 Generalized Procedure 322 Reactions Tutorial 323 Component Maps Component Map Property View User Properties User Property View Chapter 5: Oil Characterization Environment Refinery Assays 325 327 328 330 337 338 Available Refinery Assays 339 Refinery Assay Information 341 Refinery Oil Model 342 Synthesizing a Refinery Assay 345 Import Refinery Assays 376 Export Refinery Assays 381 v Contents (continued) Publish Refinery Assays 384 Assay Data Matrix 386 Bulk Assay Processing 388 Refinery Assay Synthesis Tutorial 393 Black Oil Analysis 408 Input Data 409 SCN Oil Analysis 411 Composition Input 413 Bulk Properties 414 Chapter 6: PFD/Simulation Environment vi 417 Main Flowsheet 418 Sub-Flowsheet 418 Column Flowsheet 419 Working in the PFD Environment 419 Select Objects 420 Break a Connection 420 Swap Connections 421 Quick Route Mode 421 PFD Colour Schemes 422 PFD HotKeys 424 Chapter 7: Streams 427 Material Streams 428 Define Streams from Another Stream 429 Synthesize From Another Source 430 Stream Properties 434 Stream Prices 437 Attach an Assay 444 Performing Flash Calculations 449 Worksheet 451 Synthesis 470 Attachments 474 Energy Streams 477 Stream 478 Unit Ops 478 Contents (continued) Strip Chart 479 Cost Factors 480 Synthesis Transition 481 Configuration 481 Comp. Groups 483 Plant Data 484 Diagnostics 484 Parameters 484 Synth. Methods 485 Phys. Methods Page 485 Chapter 8: General Unit Operations 487 Separator, 3-Phase Separator, and Tank 489 Design 491 Reactions 496 Rating 498 Separator Calculations 500 Mixer 502 Design 503 Rating 505 Tee 506 Design 506 Rating 508 Cooler/Heater 510 Design 510 Performance 512 Cooler/Heater Theory 513 Multistream Exchanger 515 Design 516 Performance 524 Multistream Exchanger Theory 528 Heat Exchanger 530 Design 531 Rating 542 Performance 553 vii Contents (continued) Heater Exchanger Theory 557 Geometry Design View 559 Air Cooler 577 Design 577 Rating 579 Performance 581 Air Cooler Theory 583 Pump Design 586 Rating 588 Performance 590 Pump Theory 591 Compressor or Expander 593 Design 595 Rating 601 Performance Tab 608 Compressor and Expander Theory 608 Typical Solution Methods 614 Reciprocating Compressors 614 Valve viii 585 620 Design 621 Rating 622 Relief Valve 624 Design 624 Rating 626 Relief Valve Theory 627 Pipe Segment 630 Design 631 Rating 641 Performance 657 Deposition 662 Calculation Modes 665 Incremental Material and Energy Balances 668 Profes Wax View 670 Contents (continued) Modifying the Fittings Database Continuously Stirred Tank Reactor (CSTR) 675 682 Design 683 Rating 686 Reactions 687 Plug Flow Reactor (PFR) 693 Design 694 Reactions 701 Rating 708 Performance 709 Gibbs Reactor 715 Design 716 Reactions 719 Rating 722 Equilibrium Reactor 723 Design 724 Reactions 727 Rating 732 Conversion Reactor 733 Design 734 Reactions 736 Rating 740 Gas Turbine 741 Design 742 Rating 744 Single Shaft and Twin Shaft Gas Turbines 750 Gas Turbine Theory 751 Principal Irreversibilities and Losses 752 Solution Method 753 Part Load Operation 755 Steam Injection 758 Compressed Air Extraction 758 Limits 759 Burner 760 ix Contents (continued) Design 761 Performance 764 Burner Combustion, Thermal Efficiency and Pressure Drop 765 Steam Generator Design 769 Rating 774 Performance 777 Economiser 783 Multiple Steam Pressures 784 Steam Generator Theory 788 Steam Jet Ejector 795 Design 796 Performance 798 About Steam Ejectors 800 Steam Use x 767 801 Design Tab 802 Steam Use Theory 803 Deaerator 805 Design 806 Performance 807 Plant Data 808 Desuperheater 809 Design 810 Steam Header 812 Design 813 Performance 815 Hydraulic Turbine 817 Steam TurboGen 819 Design 820 Performance 824 Plant Data 825 Basic Boiler 826 Design 827 Performance 831 Contents (continued) Plant Data 831 Turbine Group 833 Design 833 Results 836 Steam Gen Group Design Results Chapter 9: Separation Unit Operations 837 837 839 841 Column Sub-flowsheet Environment 842 Isolation of the Column Solver 842 Main/Column Sub-flowsheet Relationship 843 Main Flowsheet/Sub-flowsheet Concept 844 Connections Page (Column Runner) 845 Column Sub-flowsheet Unit Operations 846 Distillation Column Sub-flowsheet 876 Refluxed Absorber Column Sub-flowsheet 883 Reboiled Absorber Column Sub-flowsheet 889 Absorber Column Sub-flowsheet 895 Liquid-Liquid Extractor 899 Three Phase Distillation 903 Three Phase Distillation Column 904 Three Phase Refluxed Absorber Column 906 Three Phase Reboiled Absorber Column 908 Three Phase Absorber Column 909 Custom Column Sub-flowsheet 911 Column Property View 913 Petro-SIM Columns 914 Design Tips for Reactive Distillation 927 Design 929 Parameters 960 Side Ops 978 Rating 994 Performance 997 Flowsheet 1007 xi Contents (continued) Reactions 1013 Distop 1017 Shortcut Column 1038 Performance 1040 Component Splitter 1042 Design 1043 Distop 1046 Component Splitter Theory 1052 Simple Solid Separator 1054 Design 1054 Cyclone 1057 Design 1058 Rating 1060 Performance 1062 Hydrocyclone 1064 Design 1064 Rating 1066 Performance 1068 Rotary Vacuum Filter 1070 Design 1070 Rating 1072 Baghouse Filter 1074 Design 1074 Rating 1076 Performance 1077 Chapter 10: Logical Unit Operations Adjust 1079 1080 Design Tab 1081 Monitor 1087 Set 1089 Connections 1090 Parameters 1091 Recycle xii 1037 Design 1092 Contents (continued) Connections 1093 Parameters 1094 Monitor 1100 Recycle Calculations 1102 Reducing Convergence Time 1102 Optimizer 1104 Design 1104 Solution 1112 Running the Optimizer 1117 Balance 1118 Design 1119 Meter 1125 Connections 1126 Data Set 1128 Historian 1130 Corrections 1131 Solve Control 1134 Sending to a Meter 1135 Attaching a Stream to a Meter 1135 Spreadsheet 1137 Spreadsheet 1138 Parameters 1140 Connections 1141 Formulas 1142 Calc Order 1143 Stream Cutter 1145 Design 1145 Transitions 1146 Simultaneous Solver Manager 1152 Managing Simultaneous Solver Groups 1153 Managing the Adjusts SSGs 1156 Managing the Recycles SSGs 1157 Sub-Flowsheet Operation Design 1158 1160 xiii Contents (continued) PFD User Unit Operation 1167 Design 1168 Sample User Unit Operations 1171 CAPE-OPEN Unit Operation 1172 Design 1173 Parameters 1176 Options 1177 How to Write Your Own CAPE-OPEN Unit 1178 What Does Petro-SIM Need or Support? 1178 Extension Unit Operations 1180 To register extensions 1180 To add extensions to your simulation 1180 Creating a Custom Extension Unit Operation 1181 Extension Unit Operation Example 1188 Hydraulics Plugin 1205 Settings 1207 Diagnostics 1215 Results Chapter 11: Refinery Unit Operations xiv 1165 1215 1219 Refinery Feed 1220 Connections 1221 Assay Sources 1221 Product Stream 1226 Plots 1228 Plant to Crude 1229 Design 1230 Synthesis 1231 Product 1234 Assay Adjuster 1236 Design Tab 1237 Specifications 1238 Plots 1241 Assay Adjuster – Tutorial 1241 Contents (continued) FCCU Reactor 1243 Design 1245 Operating Data 1249 Catalyst 1263 Calibration 1266 Results 1277 Model Calibration 1278 Hydrotreaters 1284 Design 1285 Operating Data 1293 Calibration 1311 Results 1320 Pilot Plant Operations 1321 Hydrocrackers 1323 Design 1324 Operating Data 1327 Calibration 1332 Results 1335 HCR Reactor Configurations 1336 Catalytic Reformer 1338 Connections 1339 Operating Data 1342 Calibration 1355 Results 1363 Isomerization Reactor 1366 Connections 1366 Operating Data 1368 Calibration 1370 Results 1373 Isomerization Chemistry 1376 Aromatics Reactor 1378 Connections 1378 Operating Data 1379 Calibration 1382 xv Contents (continued) Results 1390 Aromatics Reaction Chemistry 1393 Visbreaker 1400 Design 1408 Operating Data 1411 Calibration Factors 1419 Results 1428 Visbreaker and VGO Cracker Models 1431 VGO Cracker 1441 VGO Cracker Introduction 1441 Design 1446 Operating Data 1449 Calibration Factors 1457 Results 1463 Coker Furnace 1464 Coker Furnace Introduction 1465 Design 1472 Operating Data 1475 Calibration Factors 1484 Results 1493 Fired Heater 1498 About the Fired Heater 1498 Design 1509 Operating Data 1511 Calibration Factors 1516 Results 1519 HF and H2SO4 Alkylation Reactors 1523 Design 1525 Operating Data 1526 Results 1530 Calibration 1532 Delayed Coker 1537 About the Delayed Coker xvi 1399 Visbreaker Introduction 1538 Contents (continued) Design 1547 Operating Data 1552 Calibration 1561 Results 1565 HDS 1568 Design 1569 Operating Data 1572 Refinery Blender 1575 Design 1576 Operating Data 1579 Results 1585 Pyrolysis Furnace 1588 About the Pyrolysis Furnace 1589 Design 1590 Operating Data 1592 Feed 1596 Configuration 1598 Results 1601 Reports Chapter 12: Simulation Tools Calibration Helper 1602 1603 1605 SIM Model Calibration Summary 1607 About Recalibration 1608 Recalibration Troubleshooting 1609 Case Protection 1611 Setting Basic Protection Options 1611 Setting Advanced Protection Options 1613 Advanced Specifications 1615 Unlocking a Case 1616 Compare Cases 1618 Databook 1620 Variables 1620 Process Data Tables 1623 Strip Charts 1624 xvii Contents (continued) Data Recorder 1626 Case Studies 1629 Event Scheduler 1635 Create Simple Events 1635 Create Complex Events 1642 Events Summary 1649 Graph Control 1650 Data Tab 1651 Axes Tab 1653 Title 1655 Legend 1656 Plot Area 1656 Historian Connections xviii 1658 Add a Historian Connection 1658 Read from or Write to a Historian 1664 SQL Queries for Historian Data 1665 Use Script Tags 1669 Track Variables Across Simulations 1670 Journal 1672 Knowledge Base Editor 1675 About the Knowledge Base 1676 General 1681 Details 1682 Other 1684 Lab Analysis 1686 Perform a Lab Analysis 1686 Add Streams 1688 Add Inhibitors 1689 Add Water Content 1691 View Envelopes 1693 Create Envelope Experiment 1695 Movie Recorder 1697 Multi Viewer 1698 Object Navigator 1701 Contents (continued) Petro-SIM XML 1703 Script Manager 1706 Strip Chart Configuration 1709 General 1710 Curves 1712 Axes 1713 Time Axis 1713 Printing 1714 Type Library Browser 1716 User Variables 1718 User Variables in Dynamics Mode 1718 Managing User Variables 1719 Creating User Variables 1721 Script Editor 1724 Import and Export User Variables 1730 Variable Navigator 1734 Multi Variable Navigator 1735 Single Variable Navigator 1737 Chapter 13: Utilities Assay Browser 1739 1741 Property Vectors Page 1741 Configuration Page 1742 Boiling Point Curves 1745 Design 1746 Performance 1747 CO2 Freeze Out 1751 Connections 1752 Cold Properties 1753 Design 1755 Performance 1756 Composite Curves Utility 1757 Design 1757 Performance 1759 Critical Properties 1762 xix Contents (continued) Connections 1762 True and Pseudo Critical Properties 1763 Data Recon Utility 1765 Data Sources 1766 Configure 1769 Reconcile 1773 Balances 1778 Troubleshooting 1778 Depressuring Dynamics 1779 Depressuring Dynamics Sub-flowsheet 1780 Design 1781 Performance 1800 Envelope Utility 1802 Design 1803 Performance 1803 Flowsheet Report 1807 Design Heat Exchanger Monitor Fouling 1812 1813 Objective Function 1830 Manipulated Variables 1830 Constraints and Bounds 1831 Solution procedure 1831 Debug: Reconciliation Test 1836 Cleaning Setup 1838 Cleaning Analysis tab 1845 Performance 1856 About Heat Exchanger Fouling Monitoring 1857 Hydrate Formation Utility 1867 Design 1867 Performance 1872 KPI Utility xx 1807 1874 Performance 1875 Other 1881 Contents (continued) LP Utility 1883 Data Generation 1885 Performance 1901 Analysis 1905 Sub-Model 1910 Network Solver Utility 1914 Objects 1915 Convergence 1916 Advanced 1918 Parametric Utility 1920 Configuration 1921 Select Variables 1922 Data 1926 Training 1929 Validation 1931 Neural Networks (NN) 1933 Pipe Sizing 1934 Design 1934 Performance 1936 Plot Utility 1937 Prop Vector Browser 1939 Property Balance Utility 1943 Material Balance 1944 Energy Balance 1947 Property Table 1950 Design 1950 Performance 1953 Scenarios Utility 1956 Data 1957 Settings 1961 Swing Cut Utility 1963 Tray Sizing 1964 Design 1964 Performance 1987 xxi Contents (continued) Additional Information User Property 1997 Design 1997 Performance 1998 Vessel Sizing 2000 Design 2000 Performance Chapter 14: Time Series Date Settings 2003 2005 2006 Date 2007 Timeline 2009 Strip Charts 2010 Accumulations 2012 Log 2013 Exports 2013 Alerts 2015 Chapter 15: Workflow Manager 2017 Manage the Workflows and Workflow Libraries 2018 Create a Designed Workflow 2020 Create a Workflow Library 2028 Import Workflows 2031 Publish a Workflow Library 2031 Subscribe to a Workflow Library 2032 Workflow Manager Tutorials 2033 Tutorial 1: Running a Reporting Workflow 2034 Tutorial 2: Running Data Validation Workflows 2040 Tutorial 3: Setting Flowsheet Values from Workflows 2043 Tutorial 4: Workflow Collaboration 2048 Tutorial 5: Session Workflows that Process Multiple Cases 2051 Tutorial 6: Documenting a XAML Workflow and Preparing it For Re-Use 2053 Tutorial 7: Historian Data Validation and Remediation xxii 1990 2055 Chapter 16: Databases 2059 Connect to the Database 2060 Case Export Settings 2068 Contents (continued) Create a Case History 2069 Manage Objects in the Database 2070 Collaboration 2078 Publish and Subscribe 2079 Export or Import Data 2083 Meter Data 2086 Export Meter Data 2086 Import Data 2087 Structure of the Database 2088 Database Maintenance 2090 PetroSIM_Collections 2091 PetroSIM_Objects 2093 PetroSIM_PFD 2095 PetroSIM_BLOB 2096 PetroSIM_ObjectData 2096 PetroSIM_Views 2097 PetroSIM_ViewData 2097 PetroSIM_ViewFilters 2098 PetroSIM_Units 2098 Support Tables 2099 Sample Queries 2099 Adding Your Own Report Views 2100 Chapter 17: Petro-SIM Explorer 2105 To launch Petro-SIM Explorer 2105 Database Explorer 2108 Collection Statistics 2116 Monitoring Applications 2117 Application Details 2119 SQL Queries 2125 DBO Configuration 2125 Reporting Troubleshooting Reports 2127 2133 Chapter 18: Reports 2135 Multi-Case Reports 2136 xxiii Contents (continued) Auto-Generate Reports 2136 Import Data 2138 Modify Reports 2140 Modify Report Sections 2143 Add Report Variables 2146 Add Filters 2147 Trends 2148 Save and Import XML Reports 2152 Publish and Subscribe 2153 Refinery Assay Create Templates 2157 Create Reports 2162 Create Plots 2163 Workbook 2165 Configure Workbook Tabs 2168 Exporting from a Workbook 2172 Importing a Workbook 2173 Chapter 19: Petro-SIM and MS Excel xxiv 2157 2175 Export Data to Excel 2175 Build an Excel an Application or Reporting Workbook 2176 Petro-SIM tab 2178 Export To Excel Table 2182 Custom Tables 2185 Settings 2191 Workbook Settings 2191 Add-In Settings 2193 Application Workbook 2194 Relationship with Petro-SIM 2194 Build from a Reactor Shortcut 2195 Build from a Petro-SIM Case 2219 Application Workbook Structure 2223 Application Workbook Functions 2227 Troubleshooting 2245 Reporting Workbook 2246 Contents (continued) Build a Reporting Workbook 2246 Reporting Workbook Structure 2250 Reporting Workbook Functions 2252 Reports Chapter 20: Calibration 2255 2261 Enter the Calibration Environment 2262 Objects 2263 Streams 2264 Synthesis Type 2266 DISTOP Product Specs 2267 Refinery Reactors 2271 Data 2272 Run 2275 Results Matrix 2277 Plot Results 2279 Calibration Results and Optimiser 2279 Advanced Options 2281 What Happens during Calibration 2282 Calibrating With Yields 2284 Calibration Troubleshooting 2287 Chapter 21: Refinery Modelling 2289 Refinery Physical Properties 2289 Hypocomponents, Components and Streams 2289 Refinery Assays 2290 Creating Refinery Assays from Measurements 2290 Extended Components 2292 Working with Refinery Assays 2292 Setting Up Feed Streams 2293 Looking at Refinery Properties 2294 Examining the Trace Window for Errors 2295 Unit Operations 2296 Converting Cases with Standard Oils 2296 Chapter 22: Energy System Modelling 2297 Steam Fluid Properties 2297 xxv Contents (continued) Circular Calculations 2298 Chapter 23: Dynamics 2299 Key Concepts 2301 The Solver 2301 Degrees of Freedom 2302 Static Head 2303 Nozzles 2304 Efficiencies 2305 Stream Location 2305 Specifications 2306 Backwards Calculations and Flow Reversal 2309 Start Values 2309 Inconsistencies 2309 Dynamics Sample Cases 2310 Dynamics Debutanizer 2311 Dynamics Ethanol Dehydrator 2312 Dynamic Glycol Reactor 2313 Dynamics Crude Distillation 2314 Building Dynamics Models xxvi 2314 Steady State versus Dynamics 2314 Building 2315 A Simple Model Step by Step 2315 Refinery Functionality 2318 Dynamics Tools 2319 Integrator 2319 Dynamics or Network Assistant 2322 Equation Analyzer 2337 Control Manager 2339 Dynamic Initialization 2339 Dynamics Unit Operations 2343 Streams - Dynamics 2344 Air Cooler - Dynamics 2347 Component Splitter - Dynamics 2350 Compressor - Dynamics 2352 Contents (continued) Gas Turbine - Dynamics Tab 2356 Fired Heater - Dynamics 2357 Heat Exchanger - Dynamics 2361 Heater Cooler - Dynamics 2364 Multistream - Dynamics 2365 Mixer - Dynamics 2370 Pipe - Dynamics 2372 Plug Flow Reactor 2372 Pump - Dynamics 2374 Reactors - Dynamics 2378 Tee – Dynamics 2379 Valve - Dynamics 2381 Vessel - Dynamics 2388 Tray Section - Dynamics 2395 Relief Valve - Dynamics 2400 Controllers 2402 Selector - Dynamics 2418 Transfer Function – Dynamics 2418 Digital Point - Dynamics 2419 Cause and Effect Matrix 2420 Boolean Operations 2425 Spreadsheet - Dynamics 2428 Adjust - Dynamics 2429 Set - Dynamics 2430 Flowsheets in Dynamics 2430 Meter – Dynamics 2431 Stream Cutter Unit Operation – Dynamics 2431 Refinery Feed – Dynamics 2431 Refinery Plant to Crude – Dynamics 2432 Refinery Assay Adjuster – Dynamics 2433 Dynamics Troubleshooting 2434 Chapter 24: Customization 2437 Automation and Extensibility 2438 Customizing Petro-SIM 2439 xxvii Contents (continued) Programming Petro-SIM from External Programs 2440 VBA 2440 Custom Historian Connections 2441 Deploying a Custom Connection 2448 Automation 2451 Objects 2452 Automation Syntax 2453 Key Petro-SIM Objects 2454 Extensibility 2458 Implementing Interfaces 2459 Data Types 2460 Extension Development Kit 2460 Creating an Extension 2461 Registering Extensions 2462 Extension Interface Details 2464 Extension Reaction Kinetics 2465 Extension Property Packages 2476 References 2479 Extension View Editor 2479 Accessing the View Editor 2480 Using the View Editor 2481 DefaultView Form Toolbar 2484 Widget Properties 2492 Customization FAQs 2538 Automation FAQs 2538 Extensibility FAQs Chapter 25: Petro-SIM Monitoring Applications How Petro-SIM Monitoring Applications Work Calculation flow xxviii 2441 Building a Custom Connection 2546 2567 2567 2569 Monitor Commands in Excel 2569 Petro-SIM Monitoring View 2571 UMTRegister Sheet 2573 Linking your own files into your applications 2573 Contents (continued) Build Petro-SIM Monitoring Applications 2574 Create a Basecase 2574 Configure Meters and Historian 2575 Set up Data Reconciliation 2577 Setting up Property Balance Utility 2578 Set up Reactor Monitoring Mode 2578 Perform Normalization Calculations 2579 Calculate KPIs, MPIs, and DQPs 2581 Set up Submodel Calculators 2582 Set up Writable Tags – KPI Meter 2591 Set up Links to Other Cases 2592 Configure Calibration Links 2593 Configure Reporting 2594 Configure Completion Status 2595 Configure Linked Data Reconciliation Utility 2596 Run Petro-SIM Monitoring Applications 2596 Working Up Weekly Data and the Meter Report 2599 Working through the Process 2600 Recalibrating and Regenerating Models Chapter 26: Petro-SIM LP Data Gen Applications Building Petro-SIM LP Data Gen Applications 2608 2611 2611 Application Architecture 2611 System Requirements 2612 How we use the database 2614 Building a LPDataGen App: Step by Step Guide 2614 Tutorial: creating a CDU VDU Application 2620 Customizing the LPAssayDataGen Spreadsheet 2624 Linking with Calibration Applications 2626 Petro-SIM LPDataGen Application 2628 LPAssayDataGen Spreadsheet 2629 Working through the Process 2631 Recalibrating Models 2638 Monitor Commands 2639 xxix Contents (continued) Appendix A: Standard Methods and Calculations Selecting Property Methods 2650 Property Methods 2655 Multiflash 2655 Equations of State 2659 Activity Models 2668 Chao-Seader Models 2686 Vapour Pressure Models 2688 Miscellaneous Types 2690 Chemical Reactions 2700 Equilibrium Relations 2700 Phase Equilibria 2701 Charge Balance 2701 Mass Balance 2701 Phase Equilibria 2702 Chemical Equilibria 2702 Enthalpy and Entropy Departure Calculations 2713 Equations of State 2713 Activity Models 2715 Lee-Kesler Method 2716 Fugacity Coefficient 2718 Physical and Transport Properties 2719 Liquid Density 2719 Vapour Density 2720 Viscosity 2720 Thermal Conductivity 2723 Surface Tension 2724 Heat Capacity 2725 Volumetric Flow Rate Calculations 2726 Available Flow Rates 2726 Liquid and Vapour Density Basis 2727 Formulation of Flow Rate Calculations 2728 Volumetric Flow Rates as Specifications 2729 Flash Calculations xxx 2649 2731 Contents (continued) T-P Flash Calculation 2732 Vapour Fraction Flash 2733 Enthalpy Flash 2734 Entropy Flash 2734 Handling of Water 2734 Solids 2735 Stream Information Appendix B: Refinery Physical Properties Assay Matrix Properties 2736 2739 2740 Aniline Point 2741 Aromatics Content 2741 Asphaltenes Content 2743 C/H Ratio 2744 Cloud Point 2746 Conradson Carbon Content 2753 Copper/Iron Content 2753 Freeze Point 2754 Iso-Paraffins Content 2754 Maximum Visbreaker Conversion 2757 Mercaptan Sulfur 2759 Molecular Weight 2760 Motor Octane Number 2760 Naphthenes Content 2764 Nickel Content 2766 Nitrogen Content 2767 Olefins Content 2767 Pour Point 2769 Refractive Index 2771 Research Octane Number 2772 Saturated Rings Content 2776 Sodium Content 2776 Specific Gravity 2777 Sulfur Content 2780 True Vapour Pressure 2780 xxxi Contents (continued) Vanadium Content 2781 Viscosity - Liquid 2781 Other Refinery Properties xxxii 2785 API Gravity 2786 Aromatic Blending Number 2786 BMCI 2789 Bromine Number 2790 Cetane Index 2791 Cetane Number 2793 D1160 Distillation 2794 D86 Distillation 2797 Diesel Index 2803 Flash Point 2804 Heat Value 2806 Luminometer Number 2808 Mean Average Boiling Point 2809 Molar Average Boiling Point 2810 Paraffins Content 2811 Particulate Emissions Factor 2814 Ramsbottom Carbon Content 2814 Reid Vapour Pressure 2815 Smoke Point 2816 TBP Distillation 2817 TBP Weight Distillation 2818 Thermal Conductivity 2820 Value-P 2821 Vapour Lock Index 2821 Volume Average Boiling Point 2821 Watson K-Factor 2821 Wobbe Index 2822 RFG Calculations 2823 Using the Simple Model 2823 Using the Complex Model 2824 Evaporative VOCs 2826 Contents (continued) Exhaust VOCs 2827 Running Loss VOCs 2832 Refueling Loss VOCs 2833 Total VOC Emissions 2834 Toxics Emissions 2835 NOx Performance 2837 Toxics Performance 2842 CARB Calculations 2851 Vehicle Technology Class and Weighting Factors 2851 Nitrogen Oxides Calculations 2854 Hydrocarbon Exhaust Emissions Calculations 2858 Potency-Weighted Toxics Emissions 2861 Appendix C: Synthesis Methods 2871 Physical Properties and Components 2872 Plant Data Cut Types 2874 Synthesis Input Data Requirements 2876 Plant Data Stream Types 2877 Generating TBP Curves 2878 From Distillation or Composition Data 2878 From TBP Cuts 2881 Pseudocomponent Composition 2883 Pure Component Composition 2883 Predicting Asphaltenes Content 2884 Synthesis of Assay Properties 2885 Specific Gravity 2886 SG from API Gravity 2887 Aniline Point 2889 Aromatics, Naphthenes, Olefins and Iso-Paraffins Content 2889 Converting wt% Values to lv% 2889 Aromatics 2890 Naphthenes 2891 Olefins 2891 Iso-Paraffins 2892 Di-Aromatics and Tri+-Aromatics 2892 xxxiii Contents (continued) CA, CN, CO, CIsoP, CA2, CA3 And CA4 Properties xxxiv 2893 C/H Ratio 2895 Cold Properties 2897 BMCI Method 2898 Generating Cloud Point Data 2900 Cloud Point Synthesis 2900 Generating Pour Point Data from Cloud Point 2902 Pour Point Synthesis 2903 Freeze Point Synthesis 2905 Residue Pour Point Synthesis 2905 Conradson Carbon Content 2906 Metals Content 2907 Molecular Weight 2909 Nitrogen Content 2911 Octane Numbers 2912 Crude Method 2912 FCCU Gasoline Method 2913 Refractive Index 2916 Saturated Rings Content 2917 Sulphur and Mercaptan Sulphur Content 2918 True Vapour Pressure 2919 Viscosity 2920 Converting Viscosity Values to 50°C and 100°C 2920 Synthesizing Viscosity 2922 Wax Content 2924 Pure And Naphtha Component Data 2924 Calculation Accuracy 2930 Chapter 1: Introduction to Petro-SIM Petro-SIM is the first and only process simulator capable of truly scalable modelling of all facets of processing hydrocarbons from gas-plant modelling including the production and power generation aspects of natural gas, process topsides facilities for oil and gas, through to detailed and rigorous refinery modelling including all key reaction systems. Petro-SIM fits itself to the type of modelling you want to do, offering two themes that make sure you are presented with sensible choices for available unit operations, properties and functionality. Petro-SIM Production is suited to modelling upstream or production facilities including gas plants, LNG plants and basic oil and gas separation platforms. PetroSIM provides ground-breaking technology to support benchmarking, evaluation and sustained profit improvement. Gas plant operators gain a competitive advantage and enhance profitability by reducing errors, improving decision-making and providing for easy access to asset wide knowledge and expertise. Petro-SIM Refining is suited to modelling refinery and petro-chemical processes, bringing a wide range of specialized reaction unit operations, extensive hydrocarbon characterization methods and a comprehensive range of refinery inspection properties to bear to help you build fully rigorous models of your facilities. To ease your transition to Petro-SIM's new interface, we recommend that you read through the following topics which explain the key features and how to use them. Regardless of your experience with Petro-SIM, these topics can help you maximize the effectiveness in using the Petro-SIM features: l l l l Workspace Basics Petro-SIM Desktop Working with the Ribbon Toolbar Building a Simulation v1 Chapter 1: Introduction to Petro-SIM Using the completely interactive Petro-SIM workspace, you can easily manipulate process variables and unit operation topology and fully customize your simulations using its OLE extensibility capability. Petro-SIM Advantage Whether your focus is upstream, midstream, or downstream, Petro-SIM lets operators break performance barriers and improve profitability in four ways: 1. By providing the ability to develop asset wide models and assess key economic and environmental variables within the gas plant from production through power generation. 2. Through the integration of KBC's proprietary single-shaft and twin-shaft gas turbine models into Petro-SIM flowsheets. 3. By incorporating KBC's recently acquired and comprehensive mechanisms for PVT and physical property prediction with the Infochem Multiflash™ technology. 4. By allowing operators to draw on KBC's expertise for gas plant profit improvement while leveraging the same models. These build on the considerable advantages of the Petro-SIM platform that includes: Asset Wide Models Traditionally, models have been limited in scope because plant wide models are difficult to build and maintain and because the process simulators lacked the range of unit operations necessary. Petro-SIM overcomes this: l l l Model the power generation aspects of your facility or gas plant alongside the process by incorporating gas turbine and combined cycle heat recovery operations. Model the reaction processes of the refinery alongside heat integration and separation using the SIM Series of reactor models included with Petro-SIM. Build in utility systems modelling, to get the complete picture, using the steam header and other operations that are new in Petro-SIM 5. Multiflash Oil & Gas PVT KBC recently acquired Infochem Computer Services Limited and the industry leading Multiflash PVT modelling technology. In Petro-SIM, the capability of the Multiflash models can be integrated with traditional gas-plant flowsheeting and process calculation resulting in an extremely powerful and flexible thermodynamic system for the upstream gas processing industry. AMSIM Tertiary Blended Solvents Petro-SIM contains the very latest technology from Schlumberger DBR in the area of tertiary 2v Petro-SIM Environments blended solvents for contaminant removal in acid gas sweetening, flue gas clean up and process flowsheeting. Full Range of Stream Properties Petro-SIM recognizes certain types of processing streams and adjusts its stream reports and variables for the user as needed. These rules are primarily driven by your theme choice, so for example: l l l Petro-SIM Production recognizes ‘Sales Gas’ streams, gas turbine ‘Air Inlet’ streams, ‘Sour Water’ streams, etc. and presents the user with a concise and relevant overview of the stream properties, including Black Oil properties and gas processing properties such as Wobbe Index predictions based on different LHV and GHV conditions. Petro-SIM Refining recognizes different classes of product streams by boiling range, reporting gasoline properties for gasoline range material, aviation fuel properties for the kerosene range, and so on. You can mix and match the rules and customize them to suit your needs. Petro-SIM Environments The environment design concept is one of the cornerstones on which Petro-SIM is built. Petro-SIM provides three distinct environments in which you can develop your simulations: l l l Simulation Basis Environment Oil Characterization Environment PFD/Simulation These environments let you access and enter information in a certain area, or environment, of the simulation while other areas are on hold. You cannot proceed with calculations in one environment until you are finished working in the active environment. Environments help you maintain peak efficiency while working with your simulation by avoiding the execution of redundant calculations. Refer to Environment Relationships to learn how Petro-SIM effectively uses environments. Separate desktops are available with each environment. Each desktop includes an appropriate ribbon toolbar and Home views specifically designed for interaction with their particular environment. The desktops also remember the open views, even when their associated environment is not currently active. Refer to Building a Simulation for a high-level view to creating a simulation in Petro-SIM. Use the following desktop functions to manage and explore your simulations: v3 Chapter 1: Introduction to Petro-SIM l l l l l Simulation Case View Oil Synthesis Settings Time Series Lab Analysis Workflow Manager When moving from one environment to another, desktops provide a mechanism for quickly and automatically minimizing the views that are open in one environment and maximizing the views that are open in another environment. This feature is useful when working with large flowsheets and column sub-flowsheets. Environment Relationships The diagram below shows the relationship that exists between the various environments. The arrows indicate the directions you normally move in between the environments as you are building a Petro-SIM simulation. For more information, refer to: 4v Petro-SIM Environments l l l l Advantages of Using Environments Sub-Flowsheet Environment Multi-Level Flowsheet Architecture Flowsheet Information Transfer Advantages of Using Environments If you are missing some components or assays in the main flowsheet, you can return to the Simulation Basis environment to obtain or create them. All flowsheet calculations stop until you return. This prevents calculations from taking place until you have made all changes to the fluid package. The flowsheet calculations do not resume until you instruct Petro-SIM to do so in the main flowsheet. For sub-flowsheets, the same concept works according to the hierarchy of the flowsheets in the simulation. When working inside a particular flowsheet, only that flowsheet and any below it in the hierarchy automatically calculate as you make changes. All other flowsheets hold calculations until you move to their flowsheet’s simulation environment or one directly above them on the hierarchical tree. If changing the number of trays for a column flowsheet F, enter the column flowsheet’s environment, make the changes and then re-calculate the column. Specifications can be changed from anywhere in the simulation case. Topology changes require you make the changes in the environment of that flowsheet. There are no flowsheets below F, so all other flowsheets are on hold while working on the column. v5 Chapter 1: Introduction to Petro-SIM Continue making changes until you reach a satisfactory solution for F, then return to the main flowsheet to automatically recalculate all the flowsheets based on the new sub-flowsheet solution. If making changes in sub-flowsheet D, move to its environment. Since D is above E, all flowsheets are on hold except D and E. After reaching a new solution for D, you might move up to C, which then resumes calculations. When you finally return to the main flowsheet, all other flowsheets (Main, A, B and F) resume calculations. If you move directly from D to A, Petro-SIM automatically accesses the main flowsheet, so flowsheet A has the most up-to-date information when you transfer to it. Any transfer to a flowsheet not on your “branch” of the tree forces a full recalculation. Refer also to Multi-Level Flowsheet Architecture and Sub-Flowsheet Environment. Multi-Level Flowsheet Architecture The sub-flowsheets contained in the main flowsheet of the simulation case are discrete unit operations with feed and product streams. If you are interested only in the feeds to and the products from a sub-flowsheet, you can work from the main flowsheet. If you are changing the topology of the sub-flowsheet, or viewing some information about the individual operations in the sub-flowsheet, go inside the sub-flowsheet to get a more detailed perspective. This is also referred to as entering the sub-flowsheet environment. Use the Show commands to display or hide sub-flowsheet objects on the main flowsheet PFD. This information also applies to column operations, so consider the PFD of the main flowsheet for the Sour Water Stripper simulation as shown below. From the simulation environment of the main flowsheet, the distillation column SW Stripper appears with feed and product streams (e.g., Feed, Off Gas, Bottoms). The column is also a sub-flowsheet with streams and operations of its own that provides a detailed look at the column’s internal streams and operations. Within the main flowsheet, the only sub-flowsheet streams of interest are those that directly attach to the main flowsheet. In the case of the Sour Water Stripper, the material streams Feed, Off Gas 6v Petro-SIM Environments and Bottoms and the utility streams Cooling Water and Steam are termed the Boundary Streams because they cross out of the main flowsheet’s environment into that of the sub-flowsheet, carrying information between parent and sub-flowsheets. For a more detailed look at the column, go inside the column sub-flowsheet and examine the streams and operations through the SW Stripper’s simulation environment. Inside the Column, the tray section, reboiler and condenser exist as individual unit operations. Similarly, the streams attaching these operations are also distinct (e.g., To Condenser, Reflux, Boilup, To Reboiler). Within the sub-flowsheet environment, a dedicated Workbook and PFD are available for convenient access to the information that pertains only to this sub-flowsheet. Although information is never hidden or inaccessible among the various levels of flowsheets in a simulation case, the use of the environments organizes and focuses the simulation efforts in a clear and logical manner. Multi-Flowsheet Navigation The multi-flowsheet architecture can be compared to a directory structure. The main flowsheet and its sub-flowsheets are directories and sub-directories, with the streams and operations as the files in that directory. The process information associated with the streams and operations becomes the contents of the files. In Petro-SIM, you can use the Navigator view that is designed to take advantage of this directory-like structure. Within a single view, you can easily access a stream, operation, or process variable in one flowsheet from any other flowsheet in your simulation. Click a flowsheet to see its PFD on the right-hand side. You can interact with any PFD displayed. v7 Chapter 1: Introduction to Petro-SIM The Navigator view can also be used to enter a specific environment. Right-click a flowsheet and select Enter Environment to enter its environment. Click Parent icon to return to the parent (main) flowsheet. Sub-Flowsheet Environment If you are simulating a large processing facility with a number of individual process units, instead of installing all process streams and unit operations into a single flowsheet, you can simulate each process unit inside its own compact sub-flowsheet. Modelling a large process using several flowsheets helps you to organize your work and manipulate the simulation. Sub-Flowsheet Entities Whether the flowsheet is the main flowsheet of a simulation case or contained in a sub-flowsheet operation, it has these components: Flowsheet ComDescription ponent 8v Fluid Package An independent fluid package, consisting of a property package, components, etc. It is not necessary that every flowsheet in the simulation have its own separate fluid package. Flowsheets can share the same fluid package. Flowsheet Objects The inter-connected topology of the flowsheet. unit operations, material and energy streams, utilities, etc. Dedicated PFD A Petro-SIM view presenting a graphical representation of the flowsheet, showing the inter-connections between flowsheet objects. Dedicated Workbook A Petro-SIM view of tabular information describing the various types of flowsheet objects. Dedicated Desktop The PFD and Workbook are home views for this Desktop, but also included is a ribbon toolbar specific to either regular or column sub-flowsheets. Petro-SIM Environments Sub-Flowsheet Advantages The Petro-SIM multi-flowsheet architecture provides a number of technical and functional advantages. There is no limit (except available memory) to the number of sub-flowsheets contained in a Petro-SIM simulation. The following table provides the benefits of using sub-flowsheets in a simulation: Capability Benefit Multiple Fluid Packages Each installed sub-flowsheet can have its own fluid package within a single simulation case. Flowsheet Association Flowsheet association is a design that forces the change of property methods to occur at defined flowsheet boundaries. This ensures that consistent transitions between the thermodynamic bases of the different property methods are maintained and easily controlled. Simulation Case Organization Create sub-flowsheets to break large simulations into smaller, easily managed components. This provides an effective way to keep your simulation concise, while providing the tools (desktops) to focus on one specific area of the simulation at any time. v9 Chapter 1: Introduction to Petro-SIM Capability Benefit Template Creation Build a process unit as a template style flowsheet (e.g., a refrigeration loop) and save it to disk. You can install this template into another simulation by attaching the necessary feed and product streams as you would any other unit operation. These templates are fully defined flowsheets, with a property package and components, unit operations, streams and flowsheet specifications. Once a template is installed, it is functionally equivalent to a sub-flowsheet created in that simulation case. The only difference is that a sub-flowsheet cannot be saved to disk and used in another simulation. Nested Flowsheets You can use nested flowsheets, i.e., have sub-flowsheets inside other sub-flowsheets. The only restriction on nesting is with columns because you cannot create sub-flowsheet operations inside a column flowsheet. Multi-level flowsheeting is the ideal solution if your simulation involves modelling large and complex processes. Special Flowsheet Elements Column operations and flowsheet templates are special flowsheet elements because they are also flowsheets. A flowsheet template can be a column sub-flowsheet or a more complex system. The special capabilities of the column and flowsheet template are as follows: l l l Contain their own flowsheet, meaning they possess their own PFD and Workbook. Can comprise multiple flowsheet elements. Can be retrieved as a complete entity into any other simulation case. Flowsheet Information Transfer When installing or creating a sub-flowsheet in the Simulation Environment, it appears and behaves as a single operation with one or more feed and product streams. When the values of the streams attached to the sub-flowsheet change, the sub-flowsheet recalculates as expected with any other regular unit operation. 10 v Petro-SIM Environments Each of the parent flowsheet’s streams, attached to the sub-flowsheet as either a feed or product, are associated on a one-to-one basis with a Boundary Stream inside the sub-flowsheet. Information flows between the parent flowsheet and the sub-flowsheet through these associated streams. When a connection is established across the boundary, the sub-flowsheet is automatically renamed with the name of the stream in the parent flowsheet. You can override the name reassignment later because the streams on each side of the flowsheet boundary do not require the same name. For example, you can have a stream named To Decanter in the main flowsheet connected with Decanter Feed in a sub-flowsheet. The sub-flowsheet architecture allows the consistent use of different property methods. On each sub-flowsheet’s property view, Petro-SIM allows you to control how stream information is exchanged as it crosses the flowsheet boundary. For example, you can specify that the Vapour Fraction and Temperature (specified or calculated values) of a stream in the Main simulation be passed to the sub-flowsheet. Once this information is inside, the property package for the sub-flowsheet then calculates the remaining properties using the transferred composition. Component maps are available so you can define how to handle different component lists between fluid packages. No flash calculations are required for Energy streams. The heat flow is directly passed between flowsheets. Property View Flowsheet Analysis In Petro-SIM, stream and operation property views contain information based on the current flowsheet conditions. For example, the stream property view has a page that contains information concerning all phases present in the stream. Also, certain operations have pages that display performance profiles, results, and other analytical information. Stream Analysis The material stream view displays information pertinent to stream analysis on the Worksheet and Attachments tabs. v 11 Chapter 1: Introduction to Petro-SIM The Properties page in the Worksheet tab contains detailed property correlation information about the stream. The Conditions page is a subset of available stream properties. The Utilities page in the Attachments tab is used to attach utilities to the stream, while the Unit Ops page indicates the unit operations that are attached to the stream. Refer also to Utilities for information on attaching a utility to a stream. With the stream view at its default size, the page has horizontal scroll bars. By using the horizontal scroll bar, you can scroll left and right to view the Vapour, Liquid or Aqueous phases for the stream. The Liquid phase is also referred to as the Aqueous phase because water is present in the stream. The other phases that may be present are Light and Heavy Liquid. 12 v Petro-SIM Environments Instead of scrolling, re-size the view so that all phases and properties for each phase can be seen, as shown above. Unit Operation Analysis Many unit operations in Petro-SIM have pages that contain analytical information. Most unit operations display their analytical information on the Worksheet and Performance or Results tabs. The Worksheet tab, available on all unit operations, provides access to the streams attached to the unit operation. The Performance or Results tabs may display one or more pages that display the results of the analysis. The type of analytical information found in operation property views is dependent on the operation type. Regardless of what the operation is, the displayed information is automatically updated as conditions change. For more information about unit operation analysis, refer to the specific unit operations found on these unit operation palettes: l l General Unit Operations Separation Unit Operations v 13 Chapter 1: Introduction to Petro-SIM l l Logical Unit Operations Refining Unit Operations Petro-SIM Refinery Assays Refinery assays are based on the Refinery Oil Model, a conceptual model with an associated collection of software methods for characterizing the measurements and properties of hydrocarbon materials. A refinery assay matrix is a collection of information about hydrocarbonbased material that holds the basic data needed to drive the refinery physical property system. The refinery assay matrix is organized as a series of property contribution values (defined as hypothetical) components in Petro-SIM. Oils contain predefined properties such as MON, RON, PNA, etc. You can supply your own properties. This allows you to track properties such as sulfur or mineral content, C:H ratio and percent aromatics. Crudes may be synthesized and blended and compared to raw data. A complete range of refinery inspection properties and finished product specification properties are available with refinery assays. Variable Component Properties The integration of refinery assay technology into the Petro-SIM thermodynamic architecture allows individual reactor models to predict property changes across the reactor based on feedstock properties and operating conditions. This generates property distributions for the product. Because unit operations and mixing effects alter the component properties, modelling an entire refinery accurately normally requires using several thousand components. Because the component properties in Petro-SIM are variable, the entire refinery can be modelled with approximately 100 components. Sub-Flowsheet Technology Petro-SIM inherits and benefits from all the background platform technology developed for PetroSIM in KBC’s industry-leading refinery and petrochemical simulation technologies. Some examples of unique capabilities are as follows (but not limited to): l l l l l l l 14 v Simplified ease of use Database infrastructure Advanced Excel integration Workflow integration Time Series modelling Stream synthesis structure KBC oils environment KBC Advanced Technologies Expertise l l l l l l l l Optimization utilities Extensibility Historian and meter tags Flexible stream reporting Superior solver capability Energy management Heat exchanger technology Advanced distillation column capabilities (including Distop) This technology allows you to box a collection of unit operations to manage large flowsheets. Operations may be moved into and out of sub-flowsheets and the sub-flowsheets may be copied and pasted, or turned into templates for use in other flowsheets. Predictive Properties Properties such as Octane Number, Pour Pt., Cloud Pt, etc. are predicted using industry-proven methods. Predicting these properties takes into account blending and flowsheet topology. This lets you assess your plant operations with the variables that dictate the economics. Distillation Column Capabilities Depending on the detail warranted, you might model columns in any of the following ways: l l l Distop solver, a robust algorithm which performs a section-by-section analysis that may be tuned to match plant data. Rigorous first principles column models which perform tray-by-tray analysis as currently supplied in Petro-SIM. Simple splitter where you define the outlets. KBC Advanced Technologies Expertise KBC has pioneered the development of simulation products that capture full gas-plant interactions from production to power generation. With a market leading position in refining, KBC is the world’s only supplier of refinery-wide process simulation models that include detailed individual refinery conversion units. KBC is extending the same focus and value to the upstream oil & gas production market segment. KBC’s extensive technical experience, expert knowledge, advanced technology and consulting services are capable of building and maintaining gas processing flowsheets and identify profit improvement opportunities for gas-plant throughput and energy minimization. v 15 Chapter 1: Introduction to Petro-SIM Technical Support If you cannot find the answer to your question by searching the online Help, we encourage you to contact Support directly by email: software@kbcat.com Please include the following information in your email: l l l 16 v Your full name, company name, phone and fax numbers Version that you are using (to find the version number, select Resources tab, Petro-SIM). Detailed description of the problem (attach a simulation case, if possible). About Chapter 2: Petro-SIM Workspace Petro-SIM is a versatile process simulation tool that offers a high degree of flexibility combined with a consistent and logical approach to accomplish specific tasks. Petro-SIM usability is attributed to these design aspects: Event-Driven Operation. This concept combines interactive simulation with direct access to information. Interactive simulation means the information is processed as it is supplied and calculations performed automatically. Direct access means that information can be supplied from any part of the program. Modular Operations. Modular operations mean that individual unit operations and tasks can be supplied in any order. Information is processed as it is supplied and the results of any calculation are automatically transferred throughout the flowsheet, both forwards and backwards. Multi-Flowsheet Architecture. Multi-flowsheet architecture can be used to create any number of flowsheets within a simulation. Object-Oriented Design. Separating interface elements (how the information appears) from the underlying engineering code means the same information can be entered or viewed in many locations. Each display is tied to the same process variable, so if the information changes, it automatically updates in every location. An input can be changed wherever it appears and changes are not restricted to a single location. To learn more about working in Petro-SIM, refer to Workspace Basics and Petro-SIM Desktop. v 17 Chapter 2: Petro-SIM Workspace Workspace Basics When you launch Petro-SIM, the Welcome page displays information about your current version and provides links to other information about Petro-SIM capabilities. l l Click to remove a file from the list of most recently used files. Click to pin a file so that it remains in the list, regardless of how many files are opened or closed. Numerous improvements to the Petro-SIM Desktop make it easier for you to create and manage your simulations. The Petro-SIM toolbar has been replaced with the new Ribbon toolbar and a Quick Access Toolbar. You can, optionally, set a different start-up page in your Preferences. 18 v Petro-SIM Desktop Petro-SIM Desktop The Petro-SIM Desktop main features are identified in the image below. The re-designed desktop includes a new Ribbon toolbar, a Quick Access Toolbar, and the Navigation and Preview panes. To learn more about each of these desktop features, follow these links for more information: Desktop feature Description 1 Ribbon toolbar The Ribbon replaces organizes all Petro-SIM commands and options in logical groups to exposes relevant features for the task that you are currently working on. 2 Navigation pane The Navigator pane consists of three panes: l l l 3 Quick Access Toolbar PFD Hierarchy - displays the multi-flowsheet hierarchy of your simulation. Favourites - bookmark objects, streams, and operations for quick access. Search - perform a simple or advanced search to display in the Results area. The Quick Access Toolbar, located above the Ribbon, is a v 19 Chapter 2: Petro-SIM Workspace Desktop feature Description customizable toolbar that contains the commands that you use most often 4 Title Bar Displays the name of the case that is currently active. Click the View tab on the Ribbon to switch to another case or manage your cases in the window. 5 PFD Desktop Displays the case’s process flow diagram (PFD) view. The PFD is a graphical representation of your simulation. Use the buttons and commands on the PFD tab and Operations palette to create , navigate, and manage the operations and objects in the flowsheets. 6 Preview pane Displays the property view of a selected operation or object. 7 Object Status window The Object Status window shows current status messages for flowsheet objects. 8 Trace window The Trace window displays Solver information. 9 Status bar Displays the calculation status of the object. l l l Hover your mouse over an object, field, or property in a view to view a tooltip for that function. Click the Magnifier to change the magnification level for your Petro-SIM views. The magnification setting is stored as a setting in your Preferences and is applied to all Petro-SIM views until you change it again. Right-click the Date/Time area to change the date and time format. 10 Show/Hide the Ribbon Minimize or expand the ribbon and toolbars. 11 Exit Petro-SIM Minimize or re-size the view and exit Petro-SIM. 12 Units Opens the Preferences view to the Units page where you can modify the default unit set or other Petro-SIM case preferences. Navigator The Navigator pane is only available in the PFD/Simulation environment. Click Navigator on the Home tab to show or hide the Navigator panel. The Navigator pane is made up of three separate panes: 20 v Petro-SIM Desktop l l l PFD Hierarchy - Displays the multi-flowsheet hierarchy in a directory structure, enabling you to switch between the main, sub and column flowsheets in the simulation. Favourites - Displays operation, stream or utility views or variables that you have added and want available for quick access. Search - Enables you to perform a simple text search or more advanced searches on your opened case. PFD Hierarchy The PFD Hierarchy pane in the Navigator displays the multi-flowsheet hierarchy in a directory structure, enabling you to switch between the main, sub, and column flowsheets in the simulation. l l Click the arrows to expand or collapse the sub-flowsheets in the hierarchy view. Click a flowsheet in the tree to view the selected flowsheet in the PFD view. Select a flowsheet, right-click, and then choose Enter environment to open the flowsheet and limit the Solver scope to that environment. See PFD/Simulation Environment for more information about working in the PFD environment. v 21 Chapter 2: Petro-SIM Workspace Favourites Pane The Navigator pane also contains a Favourites pane, which allows you to maintain a quick access list of operations, streams, or utilities or specific variables that you can quickly access. l l To find the object in the PFD, click the item in Favourites pane. The object is highlighted in the PFD. To open the object's view, double-click the item in Favourites pane. The object's view is displayed. If you have the Preview pane option selected in the Search pane, the view opens in the Preview pane as well as opening the object's view. Adding Items to your Favourites To add operations, streams, or utilities to the Favourites pane, right-click the title bar in an object's view and choose Add to Favourites from the context menu. 22 v Petro-SIM Desktop Adding Variables to your Favourites To add a variable from an operation, stream, or utility view, right-click the variable's value, and choose Send To >Favourites. v 23 Chapter 2: Petro-SIM Workspace Modifying your Favourites 1. Right-click the Favourites pane and choose Edit Favourites. 2. Use the Move Up and Move Down buttons in the Edit Favourites view to re-order the items in the list. 3. Variable names are displayed in the blue text and can be modified in this view. The name is updated in the PFD. 4. To remove an item from your Favourites pane, click Remove Selected Object and All Its Variables. Search Tool Petro-SIM offers two Search tools with the same functionality. To search your case, use one of these search methods: l l Simple text search - search for a text string contained anywhere in your case's objects, operations views, variable names, notes. Advanced search - search for specific objects, operations, streams, columns, workbooks, and more. To open the Navigator Search tool Click to open the Search pane. To open the Search tool Use one of these options: 24 v Petro-SIM Desktop l l l Click on the Quick Access Toolbar. On the Tools tab, Navigation group, click Press CTRL+F. Search . You can also launch the Search tool from any view by right-clicking the view's background or title bar and choosing Search this View. When you use this method, the Only Search field is automatically set to search only that view. Simple Text Search When entering text in the Search For: field, the following applies: l l Text string must be at least 2 characters long. Searches are not case sensitive. 1. Open the Search tool. 2. To perform a simple text search, enter the exact text, including spaces, you want to find in the Search For: field. Check... To search ... Search Views The text contained in the views in addition to the flowsheets. Left unchecked, it searches only the flowsheets in the case. Only Search Your currently active flowsheet that is displayed in the field. If your case contains sub-flowsheets and you want to search through all the flowsheets, leave this option unchecked. When you are done entering the search string, press ENTER or click outside the field. The search results are displayed below in the Results pane. v 25 Chapter 2: Petro-SIM Workspace 3. Click any item in the Results list to display its view in the Preview pane. 4. Double-click any item in the Results list to open its view. 5. Click the arrow on the Search For field for a list of recent search strings. Select an item from the list to perform another search. Advanced Search Use the Advanced option in the Search tool to search for specific objects, operations, streams, columns, workbooks, and more. When you choose an advanced search option, text in the Search For field is ignored. 26 v Petro-SIM Desktop 1. In the Search tool pane, click Advanced. 2. From the context menu, select an option. Choose... To find... All Objects All objects in the case in all flowsheets listed alphabetically. All Unit Operations All unit operation used in the case in all flowsheets listed alphabetically. All PFDs All PFDs (flowsheets) in the case listed alphabetically. PFD Hierarchy All PFDs (flowsheets) in the case.displayed hierarchically. All Columns All column flowsheets. All Streams All streams listed alphabetically. All Refinery Operations All refinery operations listed alphabetically. All Workbooks All workbooks listed alphabetically. v 27 Chapter 2: Petro-SIM Workspace Choose... All Objects Arranged by Type To find... All objects grouped by types and listed alphabetically. All Objects Arranged by Flowsheet All objects grouped by flowsheet and listed alphabetically. All Utilities Arranged by Type All utilities grouped by type and listed alphabetically. Error Objects All objects that did not solve. Error and Warning Objects All objects that did not solve and objects that solved with a warning. Incomplete Objects All objects with missing connections. All Objects Arranged by Status Objects arranged by status: l Error Not solved Ok Under-specified l Warning l l l Calculation Levels l l Show Calculation Levels All objects by calculation order in which they are calculated by the Solver. Show Non Default Calculation Levels Objects which have user-specified Calc levels. Streams l With Assays Attached All streams that have assays attached. l With Specified Conditions All streams with specified conditions. Notes l Show Object Notes All objects which have a Notes page or tab. l Show Objects with Notes All objects which have user-entered notes in a a Notes page or tab. Comments 28 v l Show Comments All objects which have comments added to numerical fields. l Show Comments in Views Check the Search Views option to search for comments in view. Petro-SIM Desktop Choose... To find... All comments in all views sorted by the object and variable to which the comment is attached. Assay Users All objects, excluding streams, that use an assay. Clear Results Clear the Results pane. Preview Pane Click Preview on the Home tab, Panes group to open the Preview pane on the right-side of the PFD. The Preview pane displays the property view for any object you have selected in the PFD. Click Preview again to hide the pane. To re-size the Preview pane, hover over the border until the double-sided arrow cursor appears. Drag the border to re-size it. v 29 Chapter 2: Petro-SIM Workspace Object Status and Trace Windows The Object Status and Trace windows are displayed by default. Hover over the divider and then drag the double-sided arrow to re-size the windows. Object Status Window The Object Status window displays status messages for flowsheet objects, colour-coded to match the colour of the status message on the object’s property view. Status messages displayed in yellow in a Property view are shown in black for clarity. Double-click the status in message window open the Property view of an object described in the status message. Right-click anywhere in the window to view a sub-menu of commands. 30 v Petro-SIM Desktop Select… To… View Status List Properties Open the Status List Properties view. 1. In the Status List File Name field, change the name of the log file (default Status.Log). Similarly, you can change the path for the location of the file in the Status List File Path field. The log file and path are the file and location when you select Dump Current Status List to File. 2. From the Minimum Severity drop-down list, select the severity of messages that you want displayed. 3. Click OK to save the properties. Dump Current Status List Send the contents of the Object Status window to the location and file to File specified in the View Status List Properties. Status information is appended to the log file. Copy All to Clipboard Copy all the Status messages in the window to the clipboard. Open Status File Open the Status log file, if it exists. Clear Status File Clear the contents of the log file. Trace Window The Trace Window displays detailed iterative calculations for certain operations, such as the Adjust, Recycle, Reactor, etc. All messages are displayed in black text, except for error messages, such as operation errors or warnings, which are displayed in red text. Scripting commands are displayed in blue. Right-click anywhere in the window to view a sub-menu of commands. v 31 Chapter 2: Petro-SIM Workspace Select… To… View Trace Properties Open the Trace Properties view. 1. In the Trace File Name field, change the file name to which the contents of the Trace Window can be written (default Trace.Log). Similarly, you can change the path for the location of the file in the Trace File Path field. 2. In the History Length field, change the number of lines of information that the Trace Window keeps in its history. 3. Check these options: l Trace to File Continuously to append the contents continuously to the Trace log file. l Verbose to display solver information for all operations in the case. l Trace Inactive to show information for all inactive operations in the case. 32 v Dump Current Trace to File Automatically appends the current contents of the Trace window to the Trace log file. Copy All to Clipboard Copy all messages in the Trace window to the clipboard. Open Trace File Open the Trace log file, if it exists. Petro-SIM Desktop Select… To… Clear Trace Window Clear all the information from the Trace window. Clear Trace File Delete the Trace log file. The Trace file is a Unicode text file. If a Trace file from a previous version of Petro-SIM exists, writing the current Trace window to that file may result in an unreadable file. Clear the Trace file or re-name it before writing to that file. Change the Date and Time Format Petro-SIM, by default, uses your system settings for data and time. 1. To change the format that Petro-SIM uses, right-click the Date/Time area on the status bar and select Change ”Date & Time” Format. OR From the File menu, select Preferences, Display tab, Formats page and then click the Data & Time cell. v 33 Chapter 2: Petro-SIM Workspace 2. In the Date Format Editor, enter a new format in the Date and Time fields using the following elements to define the day, month, year, hour, minutes, and seconds. You can also define the delimiter that separates each element. For example, The Example updates to show you the result as you enter the format. 34 v Use this… To define… d Day of the month in digits without leading zeros for single-digit days. dd Day of the month as digits with leading zeros for single-digit days. ddd Abbreviated day of the week, for example, Mon dddd Day of the week in full, for example, Monday. Petro-SIM Desktop Use this… To define… M Month as digits without leading 0 for single-digit months. MM Month as digits with leading zeros for single-digit months. MMM Abbreviated month name, for example, Nov MMMM Month name in full, for example, November yy Year represented only by the last two digits. A leading zero is added for single-digit years. yyyy Year represented by a full 4 digits. h Hours without leading zeros for single-digit hours (12-hour clock). hh Hours with leading zeros for single-digit hours (12-hour clock). H Hours without leading zeros for single-digit hours (24-hour clock). HH Hours with leading zeros for single-digit hours (24-hour clock). m Minutes without leading zeros for single-digit minutes. mm Minutes with leading zeros for single-digit minutes. s Seconds without leading zeros for single-digit seconds. ss Seconds with leading zeros for single-digit seconds. tt Time marker string; typically used with 12-hour notation. For example, AM or PM 3. Click OK when you are done. The Date and Time format is displayed in your Preferences and in the Date Format Editor. v 35 Chapter 2: Petro-SIM Workspace Quick Access Toolbar The Quick Access Toolbar is the small row of icons located above the Ribbon. It contains the Petro-SIM commands you use every day. By default, the Quick Access Toolbar contains the Open case, Save case, Search, Undo, and Redo commands, but you can customize it by adding any commands that you want. To customize the Quick Access Toolbar: 1. Click the Customize arrow on the Quick Access Toolbar button. 2. In the Customize Quick Access Bar view, select the down arrow next to an empty button. 36 v Quick Access Toolbar 3. From the list of commands, select the command that you want to add to the toolbar. 4. Repeat steps 2 and 3 for each command that you want to add. 5. To remove a command from the toolbar, select a command and press DELETE. Undo/Redo You can quickly undo your last action in Petro-SIM by clicking the access toolbar. Undo button on the quick After performing an Undo, the Redo button becomes enabled allowing you to redo the last undo action. Hover the mouse over the Undo or Redo button for a tooltip to appear indicating what activity will be un-done or re-done. You can also select Undo and Redo from the Tools tab. Refer to Journal for more information about managing the journal and undo entries. v 37 Chapter 2: Petro-SIM Workspace Working with the Ribbon Toolbar The Petro-SIM Ribbon replaces the toolbar and menus used in previous versions of Petro-SIM. It organizes all Petro-SIM features and commands in logical groups to expose the commands needed for your current task. The Ribbon has three main parts: 1 Tabs sit across the top of the Ribbon. Each tab represents a task-oriented activity area. 2 Commands are arranged in groups carry out a command or display a menu of commands. A command can be a button or a drop-down list. 3 Groups are sets of related commands that are available for a particular type of task. The Ribbon changes depending on what case or view you have open, what you have selected, or what particular task or environment you are working in. The Ribbon shows only those tabs and commands you are likely to need for a particular task or view. For example, if you are working in a Column sub-flowsheet, the Ribbon displays the Column tab with the commands that you need for column sub-flowsheets. Otherwise, those commands are not available. Minimize the Ribbon When working in Petro-SIM, you may want to minimize the Ribbon to get a better view of your simulations. There are two ways to quickly minimize the Ribbon. Method 1 On the top right-hand corner of the application window, click 38 v Minimize. Working with the Ribbon Toolbar To view the Ribbon, click any tab to display its contents. After you select a command, the Ribbon minimizes again. To maximize the Ribbon, click Maximize. Method 2 Double-click any tab to minimize the Ribbon. Double-click again to maximize it. Dialog Box Launcher on the Ribbon You may notice some groups have a small diagonal arrow in the lower-right corner. This arrow indicates that there is a related dialog box or a task pane that provides more options related to the group. For example, clicking the dialogue box launcher on the Pref group on the Home tab, the Preferences view opens. Some commands also have a down-arrow associated below or to the right of the command icon. The down-arrow indicates there are more options available for that button and clicking it displays those options. Tooltips For a short description for a button or object, hover your mouse over the item. A tooltip appears with a brief description of that item. v 39 Chapter 2: Petro-SIM Workspace To view a tooltip that displays the environment and mode that you are currently working in, hover your mouse over the Information icon in the top right-corner. Keyboard Shortcuts Once you are familiar with Petro-SIM, you may want to use keyboard shortcuts (Petro-SIM Hot Keys) to help you perform common tasks more quickly. Use this shortcut key(s) To do this... 40 v Create New Case CTRL+N Open Case CTRL+O Save Current Case CTRL+S Save As... CTRL+SHIFT+S Find (Search) CTRL+F Copy Active Window to the Clipboard and CTRL+L Working with the Ribbon Toolbar Use this shortcut key(s) To do this... Save it to a File Exit Petro-SIM ALT+F4 Simulation Go to Basis Manager CTRL+B Main Properties CTRL+M Access Optimizer F5 Toggle Hold/Go Calculations F8 Access Integrator CTRL+I Flowsheet Add Material Stream F11 Add Operation F12 Access Object Navigator F3 Show/Hide Object Palette F4 Composition View (from Workbook) CTRL+K Tools Access Workbooks CTRL+W Access PFDs CTRL+P Toggle Move/Attach (PFD) Access Utilities CTRL+U Access Reports CTRL+R Access DataBook CTRL+D Access Help F1 Column Go to Column View (SubFlowsheet) CTRL+T Window Close Active Window CTRL+F4 Tile Windows SHIFT+F4 v 41 Chapter 2: Petro-SIM Workspace Use this shortcut key(s) To do this... Editing/General 42 v Cut CTRL+X Copy CTRL+C (or CTRL+INSERT) Paste CTRL+V (or SHIFT+INSERT) Undo ( last action) CTRL+Z Redo (last Undo) CTRL+Y Capture the current Petro-SIM window as a screen capture. CTRL+PRT SCR Capture the current view as a screen capture ALT+PRT SCR Ribbon Groups and Commands Ribbon Groups and Commands The new Ribbon interface in Petro-SIM consists of several tabs. Some tabs are always available, but others may only be visible when specific views or options are selected in PetroSIM. For example, the Dynamics tab is only available when you are working in Dynamics mode. For help on working with the Ribbon, see Working with the Ribbon Toolbar. To see the commands available, select the tab name: l l l l l l l l l l l l l l l l File Home Time Series Workflow Manager Data Reports Oil Characterization PFD Tools Reactor/Calibration Plot Column Dynamics View Legacy Resources v 43 Chapter 2: Petro-SIM Workspace File menu The File menu lists options and buttons you can use to manage your Petro-SIM cases and options. Select… To… New Create a new Petro-SIM case. Open Open an existing case, sample case, or template. Save Save the current case. Save As Save the current case to a different file name or location. Save All Save all opened Petro-SIM cases. Print Select one of the following print options: l l l Screenshot 44 v Print – to print your case Graphic Printer – set your printer options for graphic objects. Report Printer – set your printer options for report or text objects. Save a Petro-SIM screenshot to one of the following options: Ribbon Groups and Commands Select… To… l l l l l Email Send an email using one of these options: l l l l l Workspace Active Window to Printer Active Window to File and Clipboard Active Window to Clipboard Entire Window to File Entire Window to Clipboard Email Case Email Screenshot Email Both Zip And Email Movie Email Link to Case Select one of the following commands: l l Save Workspace – save the current view layout as a workspace. Load Workspace –Load another currently open Petro-SIM case. This function allows you to toggle between cases. Close Close the current case. If you haven’t saved the case, Petro-SIM prompts you to save before closing it. Close All Closes all cases that you have open. Petro-SIM prompts you to save each case before closing it. Preferences Opens your Session Preferences where you can modify your defaults for Petro-SIM settings for the application, cases, display options, files, and locations. Exit Petro-SIM. Petro-SIM prompts you to save before closing all open cases and then exiting. v 45 Chapter 2: Petro-SIM Workspace Home tab Click the Home tab on the Ribbon to view these groups and commands. Group Select… To… Panes Navigator Open or close the Navigator pane. Preview Open or close the Preview pane. General Display the General Unit Operations palette. Separation Display the Separation Unit Operations palette. Logical Display the Logical Unit Operations palette. Refining Display the Separation Unit Operations palette. Stream Open the Material Stream Property view and adds a new material stream to the PFD. To open an Energy Stream, click the down-arrow and choose Energy. Properties Open the Stream Properties Manager in which you can create and manage individual properties and property sets that can be applied to streams in multiple cases. Pricing Open the Stream Prices view. Use this to set a feed or product stream price based on the flow, a fixed value, component flows or a property. Quick Plot Opens the Refinery Assay Property Quick Plot view for the selected stream. Operations Streams 46 v Ribbon Groups and Commands Group Select… To… Utilities Utilities Open the Utilities view which enables you to add utilities to the PFD. Lab Analysis Open the Lab Analysis view in which you can send a selection of streams to the analysis tool where you can view phase envelopes and hydrate curves. Basis Enter the Basis environment where you can define your simulation fluid packages, components, component maps, and more. Oil Enter the Oil Characterization Environment where you can create or import the oils (refinery assays) for your simulation. PFD Open the Process Flow Diagram (PFD) where you can graphically build a simulation case using icons for streams and operations, flowsheet connectivity, status of objects, and more. Calibrate Use measured data, typically stored in Petro-SIM meters, to determine new calibration parameters that allow unit operation models to more closely match real data. Parent View the parent flowsheet when you are in a subflowsheet environment. Active Activate/de-activate the Solver in Active mode. Hold Activate/de-activate the Solver in Hold mode. Re-solve Re-solve the case. Dynamics Activate/de-activate Dynamics mode. Environment Solver v 47 Chapter 2: Petro-SIM Workspace Group Select… To… PFD Mode Drag Zoom Drag selection box through an area on the PFD to zoom in on the selected area. Drag PFD Activate Drag mode where you can drag the PFD view to center the focus on a selected area of the PFD. Move Activate Move mode in which you can drag selected operations or streams to other locations on the PFD. Size Activate Size mode which allows you to resize selected objects. Select an object and then click Size. Use any of the eight handles on the object's edgesto resize the object. Attach Activate Attach mode which allows you to click and draw connections between streams and unit operations. Paste Paste the contents of the Clipboard to a selected location. Click to select one of these options: Clipboard l Paste from File - import contents from a file. Cut Cut selected content to the Clipboard. Copy Copy selected content to the Clipboard. Click to select one of these options: l l l Copy Special - copy matrix data and the labels (data types) associated with the data. Copy to File - export contents from a file Clone - duplicate selected objects. Preferences Units 48 v Open the Preferences view to the Unit Sets page. Ribbon Groups and Commands Time Series tab Click the Time Series tab on the Ribbon to view these groups and commands. Group Select… To… Time Series Setup Opens the Date Settings view to one of these tabs: l l l Date – Set up the time series date and time periods. Strip Charts – View the strip charts for a selected time series run. Accumulations - View the accumulations data for a selected time series run. Run If time series data has been defined (start and end date), initiate a run through the date period. Stop Stop a run that is in progress. Reset Reset the current time back to the start time if a start time has been defined. Applies any reset states in scenarios, clears strip charts, etc.. Scenarios Opens the Scenarios utility. Events Summary View a summary list of all simple, complex, workflow and user variable events in the case. Event Scheduler Opens the Event Scheduler view where you can configure advanced time based user logic, such as changing operation when a certain user logic condition is met. Timeline Opens the Date Settings view to the Timeline tab. Actions Results v 49 Chapter 2: Petro-SIM Workspace Group Select… To… Reports Opens the Multi-Case Reports view where you can create reports on properties and variables for selected unit operations and streams. Historian Connections Configure a historian, so that actual historical plant values are used during a date window Multi-Case Connectivity 50 v Ribbon Groups and Commands Workflow Manager tab Click the Workflow Manager tab on the Ribbon to view these groups and commands. Group Select… To… New Workflow Use these commands to create the two types of workflows that Petro-SIM supports. If more than one workflow library exists in a case, new workflows are added to the library that was last selected. Design Create a new designed workflow, and opens it in the Workflow Manager. Designed workflows are configured directly in Petro-SIM, allowing you to select a superset of objects to work against, then filter these objects using simple built-in rules, and finally perform preset actions on the objects. Import Browse for and import XAML files containing custom workflows that you have designed in Microsoft Visual Studio, or XML files that you have saved from within Petro-SIM. Library Use these commands for managing the workflow libraries in a case. Workflow Manager Opens the Workflow Manager view where you can create and manage multi-application data flows. New Create a new workflow library. Workflow libraries can be used to organize workflows and to distribute them to other users. Delete Delete a workflow library. Import Browse for and import an XML file containing a workflow library that you had saved from Petro-SIM. Subscribe Enabled only when you are connected to a database. Allows you to browse for and import workflow v 51 Chapter 2: Petro-SIM Workspace Group Select… To… libraries that have been published in the database. After subscribing to a workflow library, the case can automatically download or notify you of any new updates that are published. Multi-Case Configure Workflows that are defined within the Workflow Manager always perform actions against the particular case that owns them. Configure allows you to browse for a XAML workflow that can run against the entire Petro-SIM application. It is useful for running workflows that must open and process many Petro-SIM cases. 52 v Ribbon Groups and Commands Data tab Click the Data tab on the Ribbon to view these groups and commands. Group Select… To… Collaboration Subscriptions View all subscriptions in a case. Publish Publish objects to the database. Subscribe Subscribe to the data set. Read from Database Import unit operation data such as calibration factors from the database. Read From File Import unit operation data such as calibration factors from an XML file. Write To File Export unit operation data such as calibration factors to an XML file. Connect Open the Database Connection view. PetroSIM supports connections to the SQLite, Microsoft ACE/JET, Oracle and Microsoft SQL Server databases. Manage Open the Database view where you manage the database connections, import and export options, and database maintenance. Update Update database-linked objects. You can synchronize changes made to objects that were imported or exported to the database. Flaretot Opens the Select Database File view where you can create a new SQLite database. A setting is added to the database allowing PetroSIM to add extra Flaretot® information when Database v 53 Chapter 2: Petro-SIM Workspace Group Select… To… saving to the database. Case Export Settings Open the Case Export Settings options. Linked Objects View objects linked to the database. Import/Export/Links Connect case objects to the database. You can import objects to the database, export objects from the database, and link compatible objects to an existing database object. Build Start the Excel Application Options wizard that guides you to create a link between Petro-SIM and Excel via different workbooks. Excel Application l l Application workbook - provides a multicase interface for specifying input data for calibration and prediction runs. Reporting workbook - provides a multicase interface for viewing the results of large cases with multiple subflowsheets. Update Update Application or Reporting Workbooks. Settings Configure options for updating Application or Reporting Workbooks. Historian Connections Open the Historian Connection view where you can configure connections to process historians. Read Read meter data from: Meters l l l Write 54 v Historian Database File Write meter data to database or XML file. Ribbon Groups and Commands Reports tab Click the Reports tab on the Ribbon to view these groups and commands. Group Select… To… Multi-Case Reports Multi-Case Reports Open the Multi-Case Reporting view where you manage and organize reports. Auto Generate Select a configured report from the drop-down list to generate a new report using variables defined as KPIs in the Knowledge Base. Import Import a previously saved XML report. Subscribe Subscribe to a report that was published in your database. Print Datasheets Open the Select Objects and Datablocks to Print view in which you can select objects to print datasheets. Refinery Assay Open the Refinery Assay Report Manager view where you can create and manage Refinery Assay reports without going into the Oil Manager. Reporting Workbook Only available when a Workbook is open. Select Workbook Open the Select Workbook view to select the workbook you want to set up. Setup Open the Setup view that allows you to add, delete, and customize the tabs in the Workbook. Select and Sort, hide/show, or re-order the objects in the v 55 Chapter 2: Petro-SIM Workspace Group 56 v Select… To… Sort Order/Hide/Reveal Objects view. Import Import a workbook format or just specific pages from a file (*.wrk files). Export Export the entire workbook format or just specific pages (*.wrk files). Ribbon Groups and Commands Oil Characterization tab This tab is only available when you are in the Oil Characterization Environment. Click the Oil Characterization tab on the Ribbon to view these groups and commands. Group Select… To… Environment Basis Open the Basis environment. Oil Open the Oil Characterization Environment. PFD View the PFD environment. Clear All Deletes all refinery assays, blends, user properties, and correlation sets from the Oil Characterization Environment. You are asked to confirm before PetroSIM deletes all. Calculate All Calculate all assays and blends. Oil Synthesis Open the Case Oil Synthesis Settings view. Refinery Assay Open the Refinery Assay Report Manager for a selected refinery assay. Quick Plot Create a plot of a selected refinery assay. Refer also to Graph Control Tasks Settings Reports v 57 Chapter 2: Petro-SIM Workspace Group Select… To… View Bulk Process Process multiple refinery assays. Assay Updates Check Now Opens the Assay Updates view in which you can select and update assays that are connected to your database. Check these options to determine when the assay is updated: l l Check After Recall - checks only when you open the case containing the assay. Automatically Update - automatically updates the assay when a change is made to the database. Select Assay Updates, Check Now to check the database for available updates . Click Update to reload the assay from the database. 58 v Ribbon Groups and Commands PFD tab Click the PFD tab on the Ribbon to view these groups and commands. Group Select… To… Objects Select All Select all objects on the PFD. Send To Send selected objects to another application, utility or process: l l l l l l l l l l l l l l Excel Flowsheet Report Lab Analysis Calibration Calibration and Add Meters Data Reconciliation LP Utility Multi Viewer Meter Optimizer Assay or Prop Vector Browser Dynamic Initialization Scenario Network Solver Select Open the Select Objects view where you can locate objects by type. Hide Select: l l l Hide Objects - to hide selected objects. Hide Objects by Type - to hide all objects as the same type as a selected object. View Hidden Objects - in the Show Hidden Objects view, select the objects in the Hidden Objects list that you want to display. v 59 Chapter 2: Petro-SIM Workspace Group Select… To… Navigate Previous Select objects that are upstream from selected objects. Next Select objects that are downstream from selected objects. All Auto-position all objects on the PFD for the best possible location. Selected Auto-position selected objects on the PFD for the best possible location. Break Break a connection between a unit operation and stream without deleting them. Swap Select two streams attached to the same object and swap their nozzle connections. Drag Zoom Drag a selection box through an area on the PFD to zoom in on the selected area. Move Activate Move mode in which you can drag selected operations or streams to other locations on the PFD. Size Activate Size mode which allows you to re-size selected objects. Select an object and then click Size. Use any of the eight handles on the object's edges to re-size the object. Attach Activate Attach mode which allows you to click and draw connections between streams and unit operations. Drag PFD Activate Drag mode where you can drag the PFD view to centre the focus on a selected area of the PFD. Lock Select an object and then click Lock to lock the object to a position on the PFD. Click Lock again to unlock Auto Position Connections PFD Mode Functions 60 v Ribbon Groups and Commands Group Select… To… its position. Quick Route Activate Quick Route mode where Petro-SIM is prevented from automatically repositioning streams enabling you to move and position objects without interruption because it is repositioning streams. Auto Attach Activate Auto Attach mode. Add Text Add a text box to the PFD. In the Text Props View, enter a text string that you want to add to the PFD and click OK. Add PFD Add a new page to the PFD Notebook. The command to clone an existing PFD is available. Delete PFD Delete the active PFD without a prompt to confirm the action. Edit You cannot delete the PFD if it is the only one in the case. Rename PFD Change the PFD name. Print PFD Print the PFD to a locally attached printer. Print Setup Open the Print Setup view to change your print options. Colour Scheme Select a colour scheme for the PFD. Print Options v 61 Chapter 2: Petro-SIM Workspace Group Select… To… PFD HotKeys Display the keyboard shortcuts for PFD commands and functions. Right-click the view and select Print to print a copy of the shortcuts. Copy to Clipboard Select one of the following resolutions to copy the PFD to the clipboard: l l l l l 62 v Metafile Image Scale by 50% Scale by 100% Scale by 200% Custom Scale Ribbon Groups and Commands Tools tab Click the Tools tab on the Ribbon to view these groups and commands. Group Select… To… Edit Undo Undo your last action. Redo Redo your last action. Compare Open the Compare Database Collections or Open Cases view in which you can select and compare cases, assays, data sets or collections, or Objects.. Movie Recorder Open the movie recorder. Script Manager Open the script manager. Object Navigator Open the Object Navigator. Search Open the Search tool. Simulation Case Open the case's User Variable view. Flowsheet Open the flowsheet's User Variable view. Import and Export Open the Import and Export User Variables view. Cases Record Navigation User Variables v 63 Chapter 2: Petro-SIM Workspace Group Select… To… Code Type Library Browser Open the Type Library Browser to view functions and properties in the Petro-SIm Type Library. Petro-SIM Explorer Open the Petro-SIM Explorer to view the database as a hierarchy. Databook Open the Databook is used to systematically analyze data and monitor key process variables Knowledge Base Editor Open the Knowledge Base Editor in which you can explore the knowledge base and make modifications to it. Petro-SIM XML Open the Petro-SIM XML tool from which you can export case data to an XML1 file. Data 1XML (Extensible Markup Language) is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. 64 v Ribbon Groups and Commands Reactor/Calibration tab Click the Reactor/Calibration tab on the Ribbon to view these groups and commands. Group Select… To… Reactor Data These options are only available when you have a refinery reactor selected in the PFD. Build Excel Application Only enabled if you are not in Calibration mode. Start the Excel Application Options wizard that guides you to create a link between Petro-SIM and Excel via different workbooks. l l Send To Send selected reactor to another application, utility or process: l l l l l l l l l l l Meter Application workbook - provides a multicase interface for specifying input data for calibration and prediction runs. Reporting workbook - provides a multicase interface for viewing the results of large cases with multiple sub-flowsheets. Excel Flowsheet Report Lab Analysis Calibration Calibration and Add Meters Data Reconciliation LP Utility Optimizer Prop Vector Dynamic Initialization Scenario View the meter properties attached to the reactor. v 65 Chapter 2: Petro-SIM Workspace Group Select… To… Synthesis Open the Synthesis Settings for the selected reactor. PFD Selection Create a calibration for a select group of objects in the PFD. If there is an existing calibration, then it will be activated instead of creating a new calibration. Entire PFD Create a calibration for all objects in the PFD. Activate Activate the calibration that you select from the drop-down list. Summary Open the SIM Model Calibration Summary to view the External and Internal status for the SIM models that require recalibration. Edit Open the Calibration Applications view where you can rename or delete calibration applications. View Open the Multi Viewer to view, add or remove data such as variables. Read Read meter data from: Calibrate Calibration Groups Data l l l Historian Database File Write Write meter data to database or XML file. Reconcile View and reconcile the calibration data in the Data Reconciliation Utility. Validate Perform a synthesis run and validation without calibrating to check the synthesis data. Calibrate Synthesize the data, if necessary, and start the calibration. Run 66 v Ribbon Groups and Commands Group Select… To… Results Settings Open the Calibration Results and Optimizer view to view Variables, Algorithm, Parameters and Objective for the optimizer part of calibration. Plots View the stream distillation plots for the calibration. Diagnostics Open the calibration Diagnostics view which contains a detailed diagnostic information about the entire calibration in a plain text format. Export Assay Create refinery assays in the Oil Characterization Environment that correspond to synthesized streams. Accept Select: Action l l Import/Export Calibration Factors Only -exit Calibration mode, keeping Calibration Factors in the calibrated unit operations and reverting operating and design data and streams to use non-calibration data. All Calibration Data - exit Calibration mode and use Calibration Data for all operations. Feed streams will retain calibration values, unless they have upstream connections. Select: l l Publish To Database - Publish calibration factors to the database. Write to File - Export unit operation data such as calibration factors to an XML file. Reset Reset all calibration data and restore cut streams. Exit Exit Calibration mode. v 67 Chapter 2: Petro-SIM Workspace Plot tab Click the Plot tab on the Ribbon to view these groups and commands. Group Select… To… Settings Scale X Smart scale the x-axis. Scale Y Smart scale the y-axis Grid Visible Check to display the background grid. Legend Visible Check to display the Legend. Title Visible Check to display the graph title. Crosshair View the x and y coordinates using a crosshair as a guide. Vertical Only View the x and y coordinates using a vertical rule as a guide. Horizontal Only View the x and y coordinates using a horizontal rule as a guide. Data point dropdown list Select the data set from the drop-down list. Colour Modify the colour for the selected data set. Symbol Modify the plot symbol for the selected data set. Style Modify the line style for the selected data set. None|Solid|Gradient Modify the background type: Crosshairs Data Points Plot Background None - transparent. 68 v Ribbon Groups and Commands Group Select… To… Solid - select a Solid Colour. Gradient - select a Gradient Top and Bottom colour. Solid Colour Select a colour for the Solid background. Gradient Top Select a top colour for a Gradient colour background. Gradient Bottom Select a bottom colour for a Gradient colour background. Metafile Image Copy the plot to your clipboard as a metafile image. The copied image can be pasted into another application such as Paint or Word. Values Copy the values used to plot the graph to your clipboard. Copied values can be pasted to cells in a spreadsheet. Bitmap Copy the plot to your clipboard as a bitmap image. The copied image can be pasted into another application such as Paint or Word. Metafile Prints the plot to an Enhanced Metafile (.emf) file. Print Prints the plot to your attached printer. Setup Open the Printer Setup dialog in which you can modify your print settings. Copy Print v 69 Chapter 2: Petro-SIM Workspace Column tab Click the Column tab on the Ribbon to view these groups and commands. Group Select… To… Controls Column View Open the column property view. Run Start the colyumn solver. Reset Reset the column solver. Parent View the parent flowsheet when you are in a subflowsheet environment. Add Column Streams and Operations Refer to Column Sub-flowsheet Unit Operations for descriptions about the unit operations available in the column view. 70 v Ribbon Groups and Commands Dynamics tab Click the Dynamics tab on the Ribbon to view these groups and commands. Group Select… To… Tools Dynamics Assistant Opens the Dynamics Assistant. Dynamic Initialization Define groups of objects and then perform specific actions using the Dynamic Initialization view. Equation Summary View sets of simultaneous equations in the Equation Summary View. Event Scheduler Opens the Event Scheduler. Control Manager Access all controllers in the case using the Control Manager. DCS Switch DCS Drivers in the DCS Interface view. Face Plates Use the Face Plates view to view any Controller face plate. Controls Dynamic Solver Options Start Integrator Start the Dynamics Integrator. Stop Integrator Stop the Dynamics Integrator Steady State Switch to Steady State Mode. Integrator Open the Dynamics Integrator. v 71 Chapter 2: Petro-SIM Workspace View tab Click the View tab on the Ribbon to view these groups and commands. Group Select… To… Packages Reaction Open the Reaction Package view. Fluid Open the Fluid Package view. Main Properties Open the Simulation Case view. Oil Synthesis Open the Oil Synthesis Settings view. Case Notes Open the Case Notes. Journal Open the Journal which keeps a record of your recent Petro-SIM activities and records undo information that allows you to undo actions. Protection Open the Case Protection view where you can passwordprotect your case or enable Runtime Mode. Magnify Change the magnification settings. Arrange Desktop Cascade all views that are currently open and not minimized. Switch Windows Switch to another case. Case Settings Magnify Windows 72 v Ribbon Groups and Commands Group Select… To… Close Close the current case. Hide/Show Windows Hide or show views or palettes. v 73 Chapter 2: Petro-SIM Workspace Legacy tab Click the Legacy tab on the Ribbon to view these groups and commands. The Legacy tab is not visible by default. To view this tab, check Show Legacy tab in the Display tab, General page in your Preferences. Group Select… To… Legacy 74 v Simulation Navigator Open the Simulation Navigator. Assay Users Open the Assay Users tool to reveal which assays are being used in the case. HYPSQP Optimiser Open the SQP Optimiser. Notes Manager Open the Notes Manager. Old Oil Manager Open the Oil Characterization view. Report Manager Use the Report Manager to set up reports for printing. Flowsheet Summaries Open the Summary view to manage the streams and unit operations in your flowsheet. Excel Table Manager Open the Excel Table Manager which displays the Excel workbooks and tables that are linked to the case. Ribbon Groups and Commands Resources tab Click the Resources tab on the Ribbon to view these groups and commands. Group Select… To… Online Help PetroSIM Open the Petro-SIM online Help. DC-SIM Open the Delayed Coking online Help. FCC-SIM Open the Fluidized Catalytic Cracking online Help. Hxx-SIM Open the Hydroprocessing online Help. REF-SIM Open the Reforming Process online Help Current Form Open a help topic for the current form or view. Welcome Page Display the Petro-SIM welcome page. About PetroSIM Display the About Petro_SIM view that includes version data. KBC on the Web Open the KBC or Petro-SIM web sites. Check for Updates Check for application updates for Petro-SIM. Links v 75 Chapter 2: Petro-SIM Workspace Session Preferences Your Session Preferences define your Petro-SIM workspace information such as units, calculation methods, colours, fonts and icons for the simulation. To view or modify your session preferences, from the File menu click Preferences. Petro-SIM provides a default preference set for you that you can use as-is or modify to suit your preferred workflow standards. The Session Preferences view is made up of 3 Tabs, with each tab divided into Pages and Groups. To modify your preferences visit these tabs: 76 v Session Preferences l l l Simulation Display Files When you are done modifying your preferences, use these buttons to manage your preferences: l l l l Save Preference Set - save your current settings to your currently active preferences file. Save As - save the current settings to a different file name or location that you can load as a preference set. Reset to Defaults - reset your preferences to the Petro-SIM default settings. Load Preference Set - select a saved Preference Set for a specific environment to load and use as your preferences. Save a Preference Set 1. To save your current settings to your currently open preference set, click Save Preference Set. 2. To save your current settings to a different preference set, click Save As.. 3. In the Save Preference File view, enter a File name and, optionally, navigate to a new location, for your preference set file. Petro-SIM automatically adds the .PRF default extension. 4. Click Save. Load a Preference Set 1. To change your Petro-SIM default settings to another preference set, click Load Preference Set. 2. Select a preference set file from the drop-down list. Optionally, select Other to locate a file in another folder. v 77 Chapter 2: Petro-SIM Workspace Simulation Tab Use the Simulation tab options to define how you want to work with simulation cases. You can modify the options for simulation cases on the following pages: l l l l l l General l Journal & Log Unit Sets Streams & Unit Ops l Stream Type l Assay Comparison l Calibration l Naming Oil Synthesis l Methods l Parameters l Assay Definition Dynamics Tray Sizing General The Simulation tab, General page displays settings in the following groups: 78 v Session Preferences General Options Option Description Start new cases with pre-built basis New cases are started from a template that already has a PengRobinson fluid package using the default Refinery Large component list. Record time when notes are modified Records the system time when notes are modified. Apply global standard correlation set Apply the Standard Correlation set to all material streams in the flowsheet. By default, this option is not enabled. Allow multiple stream connections Allow a stream to be attached as a feed to more than one unit operation. By default, this option is disabled allowing only streams that are not already connected to display for selection. Confirm deletes Enables confirmation before deleting an object . If disabled, you will not be asked to confirm deletions and objects will be removed immediately. Navigate Knowledge Base by default Displays all variable navigators with the knowledge base filters for variable selection. By default, this option is disabled. Register Petro-SIM at startup Enables Petro-SIM to register itself as the default version of Petro-SIM to use when you open files in Windows Explorer or when using OLE. v 79 Chapter 2: Petro-SIM Workspace Error Handling Option Description Display errors in trace window Enable general error messages to be sent to the Trace Window. Disabled by default; you are prompted to acknowledge errors. Display recall errors in trace window Enable recall errors messages to be sent to the Trace Window. Disabled by default; case recall stops until you acknowledge the error. Negative flow status Define how streams that solve to negative flows are handled. Select: l l l OK Status - Stream displays like other material streams on the PFD (green). Warning Status - Stream displays yellow status on the PFD. Error Status - Stream displays red status on the PFD. Performance Option Description Update object status when solving By default, Petro-SIM only updates the status for all objects when the entire flowsheet is solved. Enable to update the object status when an object is solved (i.e., as Petro-SIM solves the entire flowsheet, the object status goes between “not solved” and “solved”). Petro-SIM performance is slightly degraded when enabled. Maximum number of cached Default: 350 property sets in pure Define the cache size used when Petro-SIM loads pure component component database data from the pure component database.If the cache size is too low, Petro-SIM issues a trace warning. Calculation/Responsiveness Slide the meter to define how you want the PetroSIM UI to respond: Max Responsive - the UI updates more frequently (e.g., update views, respond to mouse/keyboard) during a solve pass. Max Calculate - the UI gets less precedence while Petro-SIM is calculating. 80 v Session Preferences Security Option Description Allow safe scripting only Safe scripting is determined by the Microsoft scripting engine, which does not allow access to Excel, the file system, or other COM objects. Disable this setting if user variables, script properties, or user unit operation require access to these potentially unsafe objects. Click Register Extension to register custom extensions using the SIM Suite Registration tool. Select the Journal & Log page to modify Petro-SIM’s journal (i.e., undo) and logging features. Journal & Log The Simulation tab, Journal & Log page displays options for setting Petro-SIM’s journal and undo features. Journal entries are stored with the case, but Undo information is not. Modify the settings in these groups: Journal Because each step saved by the journal consumes processor bandwidth and memory, there is a trade-off between recording undo information and maintaining acceptable performance. The journal group allows you to tune this balance with the following options: v 81 Chapter 2: Petro-SIM Workspace Option Description View Journal for Current Act- Click to display the journal which records the recent actions in the curive Case rent case. Record journal entries Enable the journal feature and select one of the following undo options: l l l l l Do not capture undo information - disables capturing undo information. Capture basic undo information - enables capturing minimal undo information. Capture detailed undo information - enables capturing average undo information. Capture maximum undo information - enables capturing all undo information. Confirm before undoing actions - enables confirmation for all undo actions. Disabling the recording of journal entries also disables recording of undo actions. Event Log Option Description Enable event logging Enables errors to be recorded in a plain-text log file that Petro-SIM automatically creates in the default Logs directory. Maximum log file size Sets the maximum size of the log file in KB Log performance data If checked, performance data such as database connection times and license retrieval times will be recorded in the event log View Event Log Open the log file that Petro-SIM automatically created (if it exists) if you have Enable event logging checked. The log file can be opened using any plain-text editor such as Notepad. Unit Sets The Simulation tab, Unit Sets page displays the Engineering Unit Sets used in simulation cases. Some objects such as, LP Utility and Spreadsheet, perform calculations that depend on input or output values being reported in a specific unit of measure. Most objects do not have such restrictions and they can report values in any unit. Engineering Unit Sets enables you to define a specific set of conversions that can respect object requirements. 82 v Session Preferences The Unit Sets page is divided into these groups: Engineering Unit Sets Petro-SIM has five default unit sets which cannot be modified, but you can create custom unit sets which you can modify and mix SI and Field units. 1. Select the unit set you want to use as your default: l EuroSI l Field l RefineryField l RefineryMetric l SI 2. 3. 4. 5. To add a new custom unit set, click Clone. To compare the differences between two or more unit sets, click Compare. To view unit set users, click View Users. If you are connected to a database and you want to export your unit sets to the Database Unit Set, click Export to Database. Recall Options Unit set users such as, LP utility or spreadsheet, allow you to control how they behave when they are loaded into a case that is potentially using a different preference set from the one they were saved with. To specify how you want Petro-SIM to handle recall behaviour: v 83 Chapter 2: Petro-SIM Workspace Select this option... To... Match by Unit Set name Attach to a unit set with the same name regardless of the conversions it uses. For example, if a spreadsheet is saved while attached to a unit set called “MyUnitSet” that uses “C” for its temperature conversion and it is loaded using a different preference set that has a unit set called “MyUnitSet” that uses “F”, the spreadsheet will report temperatures in “F”. This setting is appropriate for spreadsheets that are reporting results and conditions and indicates that the object does not care if unit conversions are changed. Match by unit conversions Do not attach to a new version of a preference set when the conversions are different. Petro-SIM searches the preferences file for a unit set that had conversions identical to those the spreadsheet was saved with. If not found, a new unit set would be cloned. This setting is appropriate for LP Utilities and spreadsheets that are performing calculations that depend on units (e.g., a proprietary correlation that requires temperature to be input in “C”). Unit Conversions The Unit Conversions group displays all the units that are included in the selected Unit Set. Use the buttons at the bottom of the group to: l l l View unit conversion factors Add user-defined units Delete user-defined units Refer to the Display tab, Units page for information on configuring the general display units. Add a Custom Unit Set A custom unit set allows you to mix SI and Field units within the same unit set. 1. Select the unit set you want to clone from the list of available unit sets and then click Clone . A new unit set is added to the list with the same name plus an underscore and number (for example, Field_2). 2. You can, optionally, change the name in the Name field. 3. In the Unit Conversions area, modify the units by selecting a different unit from the drop-down list on the item. 84 v Session Preferences If the unit set is used by objects, Petro-SIM displays which objects are affected. 4. Click Yes to accept the change. This does not change the default Unit Sets. 5. When you are done modifying units, click Save Preference Set. The new Unit Set is saved to your current Preference Set. Compare Unit Sets Occasionally, you may have several unit sets in your preferences that are identical or very similar and may want to consolidate or remove identical unit sets. 1. To compare two unit sets, click Compare. 2. In the Compare Unit Set Conversions view, select the first unit set that you want to compare from the Unit Set drop-down in the first column. 3. Similarly, select the second Unit Set drop-down in the second column. v 85 Chapter 2: Petro-SIM Workspace 4. To add another column, select a Unit Set and click the >> button to add it to a third column. You may need to enlarge the view to see more columns. Click << to remove unit sets. 5. Check Highlight unit conversion differences to have Petro-SIM highlight, in yellow, which values are different between the selected unit sets. Delete Unit Sets You cannot Petro-SIM default unit sets or custom unit sets that are currently in use by Petro-SIM objects. 1. To delete an unused custom unit set, select it in the Engineering Unit Sets list 2. Click Delete and then select Selected Unit Set. The selected Unit Set is deleted immediately. You are not asked to confirm its deletion. 3. To delete all unused units sets, click Delete and then select Unused Unit Sets. All unused Unit Set are deleted immediately. You are not asked to confirm their deletion. View Unit Set Users Select one of these options from the drop-down list: Selected Unit Set If you've custom unit sets in your simulation, you can view which objects—LP utilities, spreadsheets, or reports—are using those unit sets. 1. In the Engineering Unit Sets lists, select a custom unit set. 2. Click View Users and from the drop-down list and then choose Selected Unit Set. The View Users button is available only if the unit set is attached to an object. 86 v Session Preferences The Unit Set view displays all objects that use the selected unit set, its Simulation Case and whether the user is locking the unit set. If Conversion is... Recall Option is... Locked Match by unit conversions Unlocked Match by Unit Set name 3. Optionally, to view the object's property view, select it and then click View selected object. 4. Click OK to return to your Session Preferences. All Unit Sets 1. To view all objects that are currently referencing a unit set, click View Users and then from the drop-down list choose All Unit Sets. The Unit Set Users view displays the User, Unit Set that it uses and the Match Type (Recall Option). 2. To modify the Unit Set or Match Type of an object, select an option from the dropdown selection list for each option that you want to change. v 87 Chapter 2: Petro-SIM Workspace 3. Click OK to return to your Session Preferences. Export Unit Sets to Database When Petro-SIM connects to a database, the Database unit set, a special unit set, is updated (or created) from the database automatically and can also be written out to the database, if necessary. This unit set is used when writing to the database, so that all information is in the same unit set and can be compared on a consistent basis (spreadsheets and LP utilities will still write to the database using their own unit sets). If you modify the units in the Database unit set, you can export the unit set back to the database where it will be stored for futures exports. 1. Select the Database unit set in the Engineering Unit Sets list and then click Export to Database. Existing data in the database may no longer be stored in database units. Add User-defined Units If you require a unit that is not available in the Petro-SIM database, you can create your own unit and supply a conversion factor. You can only add a unit to a user-defined unit set that is not currently being used by other objects in Petro-SIM. 1. In the Engineering Unit Sets lists, select the custom unit set you want to use for your simulation. 2. In the Unit Conversion list, select the unit to which you want to add a conversion factor and then click Add. 88 v Session Preferences The Petro-SIM default internal unit is displayed in the User Conversion view. 3. Change the name of your unit in the Name field, enter the conversion factor between your unit and the Petro-SIM default internal unit and select the operand (multiply or divide) from the drop-down list. 4. Optionally, enter a positive or negative conversion offset between your unit and the Petro-SIM internal unit. 5. Click OK to return to the Unit Sets page. The new unit is set as the active factor for the selected variable type in the unit set. View a Unit Conversion Factor You can view conversion factors that are used to convert units from the Petro-SIM internal unit value to the selected unit value in your unit set. 1. In the Engineering Unit Sets lists, select the custom unit set you want to use for your simulation. 2. In the Unit Conversion list, select the unit for which you want to view its conversion factor and then click View. The Normal Conversion view displays the unit name and the conversion factor used to convert the value from the Petro-SIM default value. 3. Click OK to return to the Unit Sets page in your Session Preferences. Delete User-defined Units You can only delete user-defined units. v 89 Chapter 2: Petro-SIM Workspace 1. Select the unit set you want to use for your simulation from the list of available unit sets. 2. Select a user-created unit you want to delete in the Unit Conversions group. 3. Click Delete. The unit returns to the Petro-SIM default unit. You are not asked to confirm the deletion of userdefined units. Streams & Unit Ops The Simulation tab, Streams & Unit Ops page can used to configure general settings for streams and unit operations. Modify the settings in these groups: Streams Option Description View new streams If checked, the property view for the stream automatically appears when you add upon creation a new stream. Lock properties of If checked, streams are configured to always display the properties that are new streams to associated with their stream type. To configure how stream types are defined type and which properties are associated with them, see Stream Type page. Allow multiple stream connections 90 v Allow a stream to be attached as a feed to more than one unit operation. By default, this option is disabled allowing only streams that are not already connected to display for selection. Session Preferences Distillation Columns Option Description Use wizards Column operations have an optional installation guide built in to assist you in configuring new columns. When enabled, you are guided through the column installation using the wizard. Expand tray sections To conserve space in the PFD, column tray sections are typically compressed so that only trays with feeds or draws are shown. If checked, the tray sections of new columns are fully expanded in the PFD. Automatically rename internal and external streams If checked, internal and external stream names are kept in sync. If you change the name of the external stream, the internal stream is renamed as well and vice versa. Split all feed streams for new columns If checked, any feed stream attached to new columns will have its vapour fed to the tray above the associated feed stage. Changing this option does not affect existing columns and any feed splitting options already selected. SIM Model Options Option Description Reactor recalibration When recalling a simulation case from a previous version of Petro-SIM, this option controls how reactors that require re-calibration are handled. Select: l l l Use wizards in Petro-SIM Rx Always Ask Recalibrate Automatically Do Not Recalibrate Use wizard views when starting new cases in Refinery reactor (Rx) specific versions of Petro-SIM. Spreadsheet Option Description Capitalize formulas If checked, any formulas entered in the Spreadsheet unit operation are automatically converted to uppercase. Import Labels with Select how you want to handle importing labels: Always Ask, Always Yes, or Values Always No Enable Side-by- Select how you want to handle side-by-side imports: Always Ask, Always Yes, v 91 Chapter 2: Petro-SIM Workspace Option Description Side Import or Always No For additional preferences for streams and unit operations, modify the settings on these pages: l l l l Stream Type Assay Comparison Calibration Naming Stream Type The Simulation tab, Stream Type page displays the stream type definitions and associated property sets. You can manage your custom stream types from these two groups. Stream Type Definition The stream type definition group displays the cut points for the refinery stream types available in Petro-SIM. It also contains the water fractions required for each water stream classification. Each stream type can have its own default set of properties, which can be set from the Default Property Collections group. 92 v Session Preferences 1. To create a custom type, click Manage Custom Types. 2. In the Custom Stream Types view, enter a Name and nominate its Base Type from the list of built-in stream types. The base type is required because many uses of the Knowledge Base filter stream variables based on built-in stream types (for example, automatically adding variables to meters). By associating the custom type with a built-in type, your custom type will filter accordingly. 3. Click Add to save the custom type to your user Knowledge Base file. It also adds a new entry to the Default Property Collections group so that you can choose a default list of properties for any stream that will use the type. Because the stream types and any custom property lists are saved in your user Knowledge Base, they are not necessarily available in this list for other users working on different computers unless the Knowledge Bases are synchronized. If you specify a custom stream type for a stream, the stream will still be able to maintain this setting on different machines that do not have the type configured. 4. To remove a custom type, select the custom type that you want to remove in the matrix and then click Remove Selected. v 93 Chapter 2: Petro-SIM Workspace Default Property Collections You can modify the attributes for properties that Petro-SIM uses in property collections. Click Edit Selected to open the Knowledge Base Editor where you can add, remove, or change the attributes for properties in any collection. Assay Comparison The Simulation tab, Assay Comparison page displays the default tolerances used by Petro-SIM when assays are compared for differences. These values are used when converging assays in recycles, as well as internal operations such as assay mixing. All properties are compared on an absolute basis, although viscosities are compared by their blending indices. Select one of the following options from the Behaviour on case load drop-down list to define how the values are to be applied when opening cases: Select... To... Don’t Update Tolerances Default option. Maintain the tolerances in the simulation case. Update and Resolve as Necessary Apply values from the Preference file, which may change the results of the simulation. Ask for Confirmation Prompt upon opening each case as to which option to use. Check Use different for recycles to change the tolerances for the recycle defaults from those for other operations such as mixing. 94 v Session Preferences Calibration The Simulation tab, Calibration page displays the default Distillation and Composition Types. These defaults are used when meters are first created and configured for the calibration environment. To modify the Distillation and Composition Types, select an option in each group. Naming The Simulation tab, Naming page defines how streams and operations are named when they are added to the simulation. You can specify the naming convention for each type of operation, as well as a starting number that is incremented by 1. v 95 Chapter 2: Petro-SIM Workspace For example, Energy Streams are specified to be named as Q-%d, with a starting number of 100. As a result, the first energy stream installed in the simulation will then be named Q-100, the second Q-101 and so on. The automatic naming feature is convenient when creating objects, but you are not prevented from changing the name on the flowsheet. There are no restrictions in naming streams and operations. You can use any number of alpha, numeric, or special characters (excluding, @, | and %), including spaces. Oil Synthesis The Simulation tab, Oil Synthesis page displays the default Synthesis/Physical Calculation Methods. To set default options for refinery and standard characterization oils when creating new simulation cases, modify the settings on these pages: l l l Methods Parameters Assay Definition Methods The Simulation tab, Methods page displays options for managing refinery assay data and presenting results. 96 v Session Preferences To change the physical property calculation method or synthesis method, select an option from the drop-down list for that method. For descriptions for each method, refer to Synthesis Methods and Physical Properties Methods. Parameters The Simulation tab, Parameters page defines how the refinery assay information is calculated. To change the synthesis/physical parameter, select an option from the drop-down list for that parameter. For descriptions for each parameter, refer to Synthesis Parameters and Physical Property Parameters v 97 Chapter 2: Petro-SIM Workspace IBP for distillations and FBP for distillations also apply to input and output options for the standard oil characterization. Assay Definition The Simulation tab, Assay Definition page allows you to specify default values for standard oil characterizations. Modify the settings in these groups: Default Assay Definition Option Description Bulk properties Specify whether or not you want your default view to prompt for bulk properties: Select: Used or Not Used Assay data type Set the default standard assay type. Select one of the following: l l l l l l l l 98 v TBP ASTM D86 ASTM D1160 ASTM D86-D1160 ASTM D2887 Chromatograph - if selected, no curve options are required. EFV None - if selected, no other assay definition options are required. Session Preferences Option Description Light ends Set the default Light Ends option: Ignore; Input Composition; Auto Calculate Molecular Wt. curve Set a default molecular weight curve: Not Used; Dependent; Independent Density curve Set a default density curve: Not Used; Dependent; Independent Viscosity curve Set the default viscosity curve: Not Used; Dependent; Independent Assay Specific Options Option Description Assay basis Select: l l l Liquid Volume% Mass% Mole% Extrapolation Methods For each curve type available for the Assay data type, select the Extrapolation Method: l l l Lagrange Least Squares Probability From the Apply to drop-down list, select: l l l Both -applies to both ends Upper- applies to front end of the curve Lower -applies to back end of the curve Dynamics Page The Dynamics page preferences define the default settings used when working in Dynamics mode. v 99 Chapter 2: Petro-SIM Workspace You can modify the settings in these groups: Accessibility Check this option... To... Always show Dynamics ribbon bar tab Show the Dynamics mode ribbon bar tab even if the model is in steady state mode allowing you to access some of the dynamic views such as the Control Manager while in steady state. Always show dynamics information views To view and configure dynamics information while in steady state mode. Many unit operation views have a Dynamics page tab which is hidden in steady state mode. Assistant Check this option... 100 v To... Set dynamic stream specifications in the background Have the assistant enable or disable pressure and flow rate specifications inside streams as your stream connections are made or broken. These can be seen on the dynamics mode page tab in the stream view. Experienced users can disable this option. Perform checks when switching to dynamics or starting the integrator Have the assistant perform a number of checks to alert you of any potential problems before switching to dynamics Session Preferences Check this option... To... mode or starting the integrator. Experienced users can disable this option. Confirm switching to dynamics mode Ask to confirm that you want to switch to dynamics mode. Pressure Flow Solver Check this option... Ignore convergence failures (up to five consecutive times) To... Continue integration regardless of the dynamics mode solver having any issues while converging. Other Check this option... To... Delete internal sub-flowsheet streams Delete the corresponding stream inside a flowsheet when when external streams are deleted you delete a stream connected to a sub-flowsheet. This option is, by default, not selected because in dynamics mode, this is typically not desired. Trace controller alarms Send a warning message to the trace window when alarms inside a controller are triggered. Disable journal and undo recording while integrator is running Disable journal and recording of undo actions when changes are made to a model to improve performance of the simulation. Switch to dynamics when loading XML files Always switch to dynamics mode when reading XML files that were saved in dynamics mode. Some older XML files may not be marked as having been saved in dynamics mode. In such cases, checking this option ensures that Petro-SIM switches to dynamics mode so that important information is not lost. Use this option only when importing older XML files. Tray Sizing Page The Tray Sizing page displays the default parameters for creating new tray sizing utilities. v 101 Chapter 2: Petro-SIM Workspace You can modify the default settings in these groups: Auto Section Parameters Default Description Area tolerance Enter a value for the area tolerance. The value must be between .0001 and 1. NFP diameter factor Enter a value for the NFP diameter factor. The value must be between .00001 and 1. Tray internal type Select one of the following tray types: l l l l Valve Sieve Bubble Cap Packed Packed Tray Setup Info Default Description Correlation Type Select one of the following design correlations for predicting pressure drop and liquid hold-up: l l Packing Flood 102 v SLE (Sherwood-Leva-Eckert) Robbins Specify the packing flood factor of the packed tray. The value must be between Session Preferences Default Description Factor 0.1 and 1. Maximum Flooding Specify the maximum percentage of flooding allowed on the tray. Values range from 1 to 150. Maximum dP per Length Specify the maximum tolerated pressure difference per measured length. Values range from 0.5 in H O/ft (0.4 kPa/m) to 14.7 in H O/ft (12.01 kPa/m). 2 2 Trayed Setup Info Radio Button Description General Allows you to modify the values for the following tray specifications in the General Tray grid: l l l l l l l l l Sieve Tray Foaming Factor Max Tray Flooding Weir Height Max Weir Loading D/C Type D/C Clearance Max DC Backup Allows you to modify the values for the following specifications in the Sieve Tray grid: l l l l Valve Tray Spacing Tray Thickness Hole Diameter Hole Pitch Flooding Method Max Tray DP (height of liquid) Allows you to enter values for the following specifications in the Valve Tray grid: l l l l l Orifice Type Design Manual Valve Material Density Valve Material Thickness Hole Area (percent of actual area) v 103 Chapter 2: Petro-SIM Workspace Radio Button Description l Bubble Cap Allows you to modify the values for the following specifications in the Bubble Cap Tray grid: l l l 104 v Max Tray DP (height of liquid) Hole Area (percent of actual area) Cap Slot Height Max Tray DP (height of liquid) Session Preferences Display The Display tab defines Petro-SIM interface behaviour and display settings. You can modify the display preferences on the following pages: l General l PFD l Status & Trace l Units Formats Language Appearance l Fonts l Icons l Cursors l Sounds l l l General The Display tab, General page allows you to customize the look and behaviour of the Petro-SIM user interface. v 105 Chapter 2: Petro-SIM Workspace You can modify the settings in these groups: General Options Check this... To... Use free-floating windows Allow views and windows to float outside the Petro-SIM workspace boundaries. If not checked, your views and windows are confined to the workspace area. Enable cell edit button Display an edit bar and enable cell edit in matrices. Click the edit bar to select the contents of the cell, enabling you to overwrite the value. If not checked, you cannot edit the values in cells. Clicking the edit bar Selecting the contents for editing Enable singleclick actions 106 v When enabled, matrix cells that report attachments or are derived from another input view are shown as a hyperlink when you hover over the cell, allowing you to view the source or attachment with a single click. Session Preferences Check this... To... Ribbon Options Check this... To... Use quick access bar Display the quick access toolbar. Show Legacy tab Display the Legacy tab commands. Use ribbon theme Change the display to use the Ribbon's theme colours. Petro-SIM Theme Choose this... To do this when you create a new case... Combined Ask to select the type of case you want to create. Petro-SIM Refining Automatically create a Petro-SIM case using the Refining theme. Petro-SIM Production Automatically create a Petro-SIM case using the Production theme. Welcome Page Choose this... To... Show Welcome Page When enabled, the Petro-SIM Welcome Page web page and a list of on startup recently used cases are displayed when Petro-SIM starts up. URL for custom Welcome Page To modify the start-up screen to display a different web page such as your company's own start-up page, enter the URL for that page in this field. PFD Desktop Choose this... To... Show distillation columns Determine whether or not distillation columns are shown in the Navigator pane’s PFD Hierarchy. Initial width (percent) Set the default initial width of the Navigator pane as a percent of v 107 Chapter 2: Petro-SIM Workspace Choose this... To... horizontal screen area when you open existing cases. Maximum initial width (pixels) Set the maximum initial width of the Navigator pane in pixels when you open existing cases. Show Tooltips Tooltips, or flybys, are information pop-up boxes that appear when your cursor hovers over an object or cell. Check this... To... Show Tooltips Activate the tool tips. When checked you can modify the remaining options in this group. Value in RefineryMetric Units Display the value in RefineryMetric units in the tooltip. Value in RefineryField Display the value in RefineryField units in the tooltip. Units Value in EuroSI Units Display the value in European SI units in the tooltip. Value in Field Units Display the value in Field units in the tooltip. Value in SI Units Display the value in SI units in the tooltip. Value Source Display the operation that calculated the value in the tooltip. Show tooltips for all controls Display context information about the control in a tooltip when you hover over control items such as buttons, options, check boxes, etc. If not checked, hovering over a control item displays information about the control in the status bar. PFD The Display tab, PFD page displays the PFD display preferences. 108 v Session Preferences You can modify the settings in the following groups: General Check this... To... Show Tooltips Enable the key variables of an object to display when the mouse hovers over it. Show preview pane Display the property view of the operation that is currently selected in a pane on the right side of the PFD. Enable undo Capture undo information about PFD movements and transformations. Enable cross hairs Change the cursor to cross hairs that extend across the PFD. v 109 Chapter 2: Petro-SIM Workspace Performance In this field... Enter... Stream crosscheck limit The number of streams that should be checked when stream lines cross in the PFD. For very large PFDs, this can be computationally expensive as each stream must check if it crosses every other stream. This option limits the number of streams that are checked. A value of 0 indicates that vertical spacers should never be inserted and an <empty> value means that all streams should be checked. Rigorous routing block limit The maximum number of PFD operations that are analyzed when a PFD is routed (e.g., for auto-positioning) A value of 0 indicates that rigorous routing should be skipped and an <empty> value means that all blocks should be analyzed. Status and Trace The Display tab, Status and Trace page defines the settings for the Object Status and Trace windows in Petro-SIM. Units The Display tab, Units page enables you to configure the conversion units that Petro-SIM displays when you right-click a value. This allows you to separate your personal unit preferences from the engineering units that might be used to perform spreadsheet calculations. 110 v Session Preferences You can modify the default display units. In addition you can view the conversion factors for the default display units and add or delete user-defined display units. Change the Default Display Units 1. In the Display Units group select the unit you want to change. 2. Click the down arrow next to the unit to view all available convertible units for that unit type. For example, for Temperature, you see C, K, F, R, plus any user conversions that were added. Add User-defined Display Units If you require a display unit that is not available in the Petro-SIM database, you can create your own unit and supply a conversion factor. v 111 Chapter 2: Petro-SIM Workspace 1. Select the unit for which you want to add a conversion in the Display Units group. 2. Click Add. 3. In the User Conversion view, change the name of your unit in the Name field, enter the conversion factor between your unit and the Petro-SIM default internal unit and select the operand (multiply or divide) from the drop-down list. 4. Optionally, enter a positive or negative conversion offset between your unit and the PetroSIM internal unit. 5. Click OK. The new user-defined unit is added to the list of units and can be selected as your default display unit. Delete User-defined Display Units You can only delete user-defined display units. 1. Select the unit that you want to delete in the Display Units group. 2. Click Delete. The display unit returns to the Petro-SIM default unit. You are not asked to confirm the deletion of user-defined units. Formats The Display tab, Formats page displays the numeric format for variables. 112 v Session Preferences You can modify the variable formats or reset them to the default formats. Edit Variable Formats You can modify the format for any variable in the Variable Formats list. To modify the Date & Time format, refer to Change the Date and Time Format. 1. Select the variable that you want to modify from the Variable Formats grid. Use the CTRL or SHIFT keys to select more than one variable. 2. Click Edit. v 113 Chapter 2: Petro-SIM Workspace 3. In the Real Format Editor view, select the format you want to use: Select... To change the format to... Exponential Display the values in scientific notation. Set the number of significant digits after the decimal point in the Significant Figures field. For example: Entered or calculated value: 10000.5 Significant Figure: 5 (includes the first whole digit) Final display: 1.0001e+04 Fixed Decimal Point Display the values in decimal notation. Set the number of whole digits and significant digits after the decimal point in the Whole Digits and Decimal Digits fields. For example: Entered value: 100.5 Whole digits: 3 Decimal digits: 2 Final display: 100.50 If the entered or calculated value exceeds the specified whole digits, values are displayed as Exponential, with the sum of the specified whole and decimal digits being the number of significant figures. If the Display sign if zero check box is checked, the sign of the number entered or calculated that is rounded to zero is displayed. Significant Figures Displays the values in either decimal notation or scientific notation. Enter the number of significant digits to display after the decimal point in the Significant Figures field. Example 1: Entered or calculated value: 100.5 Significant Figure: 5 Final display: 100.50 Example 2: Entered or calculated value: 10000.5 Significant Figure: 5 Final display: 1.0001e+04 114 v Session Preferences 4. Click OK to accept the changes and return to the Formats page. Reset Variable Formats Select... To... Reset Revert the format of a selected variable back to the Petro-SIM default Reset All Revert all variables back to the Petro-SIM default formats. Language The Display tab, Language page allows you to change Petro-SIM's user interface language. You can modify the language settings as follows: v 115 Chapter 2: Petro-SIM Workspace Translation Use this... Locale To... Select the language that you want to use. The languages available is determined by the number of translation file available in your application data directory (C:\Documents and Settings\All Users\Application Data or C:\ProgramData) Currently, Petro-SIM distributes translation files for these languages: l l Translation file folder Click Chinese Russian (ellipsis) to navigate to and select a directory other than the default directory for the translation file(s). Translation file Displays the full path and filename of your currently selected language. For example C:\ProgramData\PSLang_en-US.txt Activate Translation Check this box to load the translation file (if one exists) from disk and start translating views. Translation stops when this option is unchecked and the translation file is saved out if the file was modified. Use Unicode font Check to display Unicode characters if you do not want to install support for a specific language. If you have activated a translation 116 v If you have activated a translation and want to edit the translation file, click to open the editor view: Session Preferences Use this... To... The view has three options: Show All Translations - Translations are sorted by string length and then alphabetically. Show Recent Translations - Translation is performed on the fly while views update (repaint). This page shows recent translations. The view contents changes if you flip a page on another view for example. So if you see something in a view which is not getting translated properly, you can use this option to find it quickly. Filter - Allows you to search for strings in the translation table. All strings that contain the given substring are shown. v 117 Chapter 2: Petro-SIM Workspace Use this... To... By default you cannot edit a translation in the view unless you check Lock for edit because the translation table is dynamic and changes as views paint or get edited. To change a value, lock the translations, enter a translation and unlock it again. The view repaints using the new translation. You can trigger a repaint by closing and opening a view, minimizing Petro-SIM, or minimizing a view. Check for Updates If you have activated a translation and would like to check for updates to that file, click this button. Petro-SIM compares your current translation for recent changes. Check one of the following options to check for updates manually or automatically: l l Never check automatically Always check for updates External Editor Modify the settings in this group if you want to create or modify a translation file. Use this... To... Editor Select the editor that you want to use to modify the translation file. The full path and editor executable name are displayed in the field. Edit Opens the translation file that you have selected. You must activate the file before you can modify it. You cannot modify the default PSLang_en-US.txt file. For more information about language support for Petro-SIM, click the image. Appearance The Display tab, Appearance page displays the default colour scheme for all features and views. You can customize the colour scheme for each feature in the Color name list to another colour. 118 v Session Preferences Petro-SIM default colour settings for text in cells and fields are: l l l Black text indicates a value calculated by Petro-SIM that cannot be changed. Blue text indicates a value you can enter or change. Red text indicates a default value in Petro-SIM that can be changed. Select Custom Colours 1. Select the component that you want to modify from the Colour name list. The default (or current selection) colour is shown in the Current colour box. 2. To change the colour, do one of the following: l Double-click the Current colour area and pick a colour from the Color palette. l Select a system colour from the Select System Colour drop-down list. If you select <Custom>, click Select Custom Colour and pick a colour from the v 119 Chapter 2: Petro-SIM Workspace Color palette. Set Legacy Colours Click Set Legacy Colours to change the PFD default colours to use the Petro-SIM version 4.1 colour scheme instead of the new v5 colour gradients. Set Light PFD Colours Click Set Light PFD Colours to change the PFD background to white. This feature is useful for taking screenshots. Reset to Defaults Click Reset All Colours to reset the colour scheme to Petro-SIM default colours. Fonts The Display tab, Fonts page defines the Petro-SIM font scheme. You can customize the font for each component in the Font name list. 120 v Session Preferences Petro-SIM uses Segoe UI as its default font. Modify Component Fonts 1. Select the component in the Font name list that you want to modify. The default (or current selection) font is shown in the Current font box. 2. To change the font, do one of the following: l Double-click the Current font area and pick a Font, Font style and Size from the Font view. l Select a font from the Select system font drop-down list. If you select <Custom>, click Select Custom font and pick a Font, Font style and Size v 121 Chapter 2: Petro-SIM Workspace from the Font view. 3. Optionally, test the font size in the Test scaling field. Use Unicode font Petro-SIM is able to display Unicode characters, but depending on the regional settings of your computer, may in some cases require selection of a font that supports Unicode characters, such as Arial Unicode MS (available if Office is installed). Reset All Fonts Click Reset All Fonts to reset all fonts to use Petro-SIM default fonts. Icons The Display tab, Icons page shows the default icons that Petro-SIM uses. 122 v Session Preferences You can change the icon for any component listed in the Icon name list. Modify Component Icons 1. Select the component in the Icon name list that you want to modify. The default (or current selection) icon is shown in the Current icon box. 2. To change the icon, do one of the following: l Double-click the Current icon area and pick a different icon from the Internal Icons view. l Select a system icon from the Select system icon drop-down list. If you select <Custom>,click Select Custom Iconand pick a different icon from the Internal Icons view. v 123 Chapter 2: Petro-SIM Workspace The Internal Icons palette displays all icons available in Petro-SIM. You can select any icon in this palette, or click Browse to locate a custom icon file (*.ico) that you want to use. 3. Optionally, test the icon alignment using the Test alignment buttons. Reset All Icons Click Reset All Icons to reset all components to use the Petro-SIM default icons. Cursors The Display tab, Cursors page displays the components that use cursors. You can modify each component to use a different cursor. Modify Component Cursors 1. Select the component in the Cursor name list that you want to modify. The default (or current selection) icon is shown in the Current cursor box when you hover over the area. 124 v Session Preferences 2. To change the cursor, do one of the following: l Double-click the Current cursor area and pick a different cursor from the Internal Cursors view. l Select a system cursor from the Select system cursor drop-down list. If you select <Custom>, click Select Custom Cursor and pick a different cursor from the Internal Cursors view. The Internal Cursors palette displays all cursors available in Petro-SIM. You can only select cursors from this palette. Reset All Cursors Click Reset All Cursors to reset all components to use the Petro-SIM default cursors. Sounds The Display tab, Sounds page allows you to modify the sound that you want to hear when the solver has finished. v 125 Chapter 2: Petro-SIM Workspace 1. In the Solver Done Notification group, select Play sound if steady state solver takes longer than check box and then enter a time and time unit in the field for the minimum time to trigger a notification. 2. To hear the Petro-SIM default sound (ping), click Test Sound. 3. To modify the current sound, click Select Audio File. 4. In the Open File view, locate the sound file (*.wav) that you want to use and then click Open. 5. Check Enable sound capture in movie recorder if you want to capture sounds in your movie recordings. 126 v Session Preferences Files The Files tab is used to configure various aspects of document management within Petro-SIM, including default file and database locations and how internal and Excel reports are formatted. You can modify the settings on these pages: l General Locations Database Datasheets o Text Format o Reported Data o Company Info l Import Export l l l General The Files tab, General page lets you modify file preferences in these groups. v 127 Chapter 2: Petro-SIM Workspace File History Option Description Maximum number of recently used files Set the number of recent files available in the File menu. to show in the menu Clear History Clear the most recently used list. Auto-Recovery group 128 v Option Description Save auto-recovery cases every When checked, Petro-SIM regularly saves an auto-recovery case at the specified time interval. Enter or select the number of minutes to specify the time between each save. Check for auto-recovery files on startup If Petro-SIM crashed while you were working, it creates an auto-recovery file for each case that you had open with the most recently saved data. Check this box to display the recovery files the next time you open Petro-SIM. Session Preferences Backups group Option Description Number of case backups automatically maintained Controls the number of backup cases made when a case is saved. When selected, Petro-SIM maintains the specified number of backups of each simulation, using the extension bk?. For example, the newest backup is bk0, the next newest bk1, etc. Cascade backups on every save This check box is used in conjunction with the “Number of case backups automatically maintained” option. If enabled, a new backup will be created every time the case is saved. If not enabled, it will only save a backup if the most recent existing backup is more than one day old. General group Option Description Validate file integrity after storing When enabled, Petro-SIM will alert the user of potential file corruption. Such problems are typically hardwaredependent and not specific to Petro-SIM. Save screenshots to disk When taking window snapshots using <Ctrl>-L, this option determines if the screenshot will be saved to disk. The screenshot will always be copied to the clipboard regardless of this setting. Locations The Files tab, Locations page displays the default paths for Petro-SIM file locations and the default file names used for Petro-SIM generated files. v 129 Chapter 2: Petro-SIM Workspace For example, Petro-SIM uses %CSIDL_MYDOCUMENTS%\KBC\Petro-SIM Cases as the location and folder when you save new cases. If you want to change to a different location or folder name, type the new path and folder name using standard Windows operating system file paths and naming conventions. The path can contain regional characters and can also contain references to the location of special Windows folders such as %AppData% or %CSIDL_MYDOCUMENTS%. To change the name of the Default file Names, type a new file name, ensuring you use the correct file name suffix. Database Page The Files tab, Database page allows you to control how Petro-SIM connects to a database, as well as how much data is written to a database when saving cases. 130 v Session Preferences You can modify the options in the following groups: Export Options Check... To Write extra information to the database Write distillation column estimates and basis information to the database. The binary case is already usually saved to the database if this information needs to be reviewed. If you want to rebuild the case from tabular information rather than opening the binary case, then basis information would be required. By default this option is not checked to reduce the amount of time and space it takes to save cases to the database. Save PFD information to the database Save the PFD information so that when cases are rebuilt from the database, objects in the PFD are repositioned correctly. By default this option is not checked. PFD information is omitted from the database in tabular format to reduce the amount of time and space it takes to save a database case. v 131 Chapter 2: Petro-SIM Workspace Check... To Save PFD SVG information to the database Add detailed information to the PFD tables in the database, providing standardized Scalable Vector Graphics (SVG) information and allowing third party drawing applications to reconstruct the PFD in great detail. By default, this option is not checked because Petro-SIM does not use this information. Case Settings Open the Database Save Options for This Case view in which you can customize in detail what information should be written to the database. Password Options Check... To Encrypt passwords Mask the password when it is typed and encrypt it when saved in the registry for future automatic connections. Persist passwords Store passwords in the registry for future automatic connections, or when selecting a recent connection. Connection Settings Check Preference File to use the database connection parameters stored in the Preferences file and have them override the standard connection details that are stored in Registry. For more information about Databases, see Databases. Datasheets The Files tab, Datasheets page provides options for formatting and specifying the appearance of your printed reports. 132 v Session Preferences You can modify the settings in these groups: Format Check... To.. Shading Shade headings, footers and titles in reports. Line numbers Print line numbers on the left side of the report. Thick borders Draw thicker border lines than the other lines in the report. Indicate user specified Show all user-specified values in the Datasheet with an asterisk (*). Start datasheet on new page Start each Datasheet on a new page. Empty text Specify how empty values are displayed in datasheets. You can change the default characters used to denote empty values. Unit set Select the engineering unit set you want your Datasheet to use. This provides the option of printing Datasheets with unit sets different than your display units. For example, your display units may be in SI, but you can generate reports in Field units. v 133 Chapter 2: Petro-SIM Workspace Page Margins In these fields... Do this... Top, Bottom, Set the margins of your page. The values are the distance in inches from the edge of the page. Left, Right Paper Options In this field... Do this... Paper size Select the size of paper you want for printing. Orientation Select the orientation of the data on the paper: l l Portrait Landscape Text Format The Files tab, Text Format page provides options for manipulating text output for Reports. 134 v Check... To... Use delimiting by default Always delimit the text file. Title description visible Add a title that includes name of the object and the tabs in the Report. Session Preferences Check... To... Header field visible Add a header with the company information and the date the report was created. Footer field visible Add a footer with the Petro-SIM version and build number. Fields padded for alignment Add spaces between each field to align the fields. Disable column wrapping Disable column wrapping. Text that goes past the edge of the page will not wrap to the next line. Empty text Specify how empty values are reported. Delimiter Specify which character to use as the delimiter in your text file. The Petro-SIM default is comma delimited (,). Reported Data The Files tab, Reported Data page lets you customize which categories of streams and operations you want to report. Select each Datasheet type and de-select the Datablocks that you do not want to appear in reports. Company Info The Files tab, Company Info page allows you to customize the company information section on your reports. v 135 Chapter 2: Petro-SIM Workspace Petro-SIM does not automatically resize a bitmap file to fit the logo box on this page. The maximum logo size that can be accommodated by the logo box is 6.55 cm wide by 2.38 cm high. 1. In the Company Name field, enter the company name you want displayed in the report header. 2. In the Company Location field, enter the company location that you want displayed in the report header. 3. To add a company logo, click the Select button. 4. In the Open File view, browse to the location of your bitmap file. The logo picture must be a bitmap (*.bmp). 5. Select the file you want to import and click Open. Import Export The Files tab, Import Export page allows you to set options used when exporting data to Excel. 136 v Session Preferences Excel Table Export Options Check... To... Format font Apply formats as follows: title row is bold, input values are blue and calculated values are black. Format lines Add borders to each column, as well as the overall table, in Excel. Set column widths Automatically adjust the column widths depending on how much data is in the table. De-select this feature if your worksheet already contains other data. In Excel, if the column is not wide enough to properly display a number, it displays the value as “###”. Manually make the column wider to view the values. Add a title row Make the first row a title row in the Excel table. Add update buttons Insert two buttons below the table that can be used to get the current values from Petro-SIM or send values from Excel back to Petro-SIM. Use single column format Place all information in a single column. Refer the Exporting a Workbook for more information about exporting to Excel. XML File Format Older versions of Petro-SIM and HYSYS read and write XML files using the ASCII (plaint text) format, which does not support certain regional (non-English) characters. By default, Petro-SIM v 137 Chapter 2: Petro-SIM Workspace currently uses the UTF-8 format, which supports regional characters and can generally be read back into older versions. For some languages (e.g., Chinese), using the UTF-16 format may be more stable and result in smaller XML files. Hx Monitor De-select Export failed simulations to %TEMP% if you do not want the Heat Exchanger utility to generate failed output to this directory. H/CAMS Crude Import Name The H/CAMS options are used when importing an H/CAMS assay via the crude selector dialog box. It determines the name and short name (typically used in LP generation) of the assay. 138 v Chapter 3: Building a Simulation 1. Create a new simulation case using the options on the File – New command. l Petro-SIM Refining Case opens a new Refining case from a prebuilt template that already contains a fluid package. You will be placed in the main simulation environment. l Petro-SIM Production Case opens a new Production case from a prebuilt template that already contains a fluid package. You will be placed in the main simulation environment. l Case from scratch opens a blank case and leaves you in the Simulation Basis environment so you can define the fluid package. 2. Inside the Simulation Basis environment, you can: a. Create a fluid package and define pure components from the Petro-SIM pure component library. b. Create and define any hypothetical components. 3. Define reactions if you want to create a reactor with your own reactions. The specialized Refinery reactor unit operations do not need reactions defined. At this point, you have two options: a. If you have a refinery assay to characterize in the Oil characterization environment, you can proceed to step 4. b. If you are not entering assays in the oil environment, proceed to step 5. 4. Enter the Oil Characterization environment, where you can: a. Define one or more Assays. b. Import assays from external sources such as the Petro-SIM database or xml files 5. Enter the main flowsheet environment, where you can: a. Create assays using the Plant to Crude unit operation or access assays created in the Oil Environment b. Install and define streams and unit operations in the simulation case’s main flowsheet. v 139 Chapter 3: Building a Simulation c. Install unit operations, such as reactors, columns,and sub-flowsheets as necessary into the main flowsheet. 6. Enter a tray-to-tray Column or sub-flowsheet environment when you need to make topological changes, or if you want to take advantage of a sub-flowsheet environment’s separate Desktop. You can move between the flowsheet environments at any time during the simulation. The arrows in the diagram show that the column and sub-flowsheet environments are accessible only from the main flowsheet. This is one way of moving between the environments. You can also use the Navigator to move from one flowsheet to another or click switch to the parent flowsheet. Parent to Simulation Case View To open the Simulation Case view, from the View tab, select CTRL+M. Main Properties or press The Simulation Case view consists of two tabs: l l Main - used to define your case theme and standard properties for the simulation. Licensing - defines the Petro-SIM licenses that the case uses and allows you to configure Runtime mode, if available. Main Tab The Simulation Case view's Main tab is made up of these pages: 140 v Simulation Case View Properties The Properties page on the Main tab allows you to access tools that apply to your entire flowsheet. In the Standard Conditions area, define the standard conditions that impact calculations and the conversion of stream flow rates for the case. Modifying the conditions forces the case to recalculate. Click Convert to Template to convert the case to a template. Status The Status page on the Main tab allows you to view any errors or warnings in your case, name the flowsheet and provide a tag for it. The data displayed can be sorted by right clicking on the matrix. v 141 Chapter 3: Building a Simulation The Object Status group displays the current status messages for all objects in the simulation case according to the minimum severity. In the Minimum Severity drop-down list, click one of the following options: Option Description OK Sets the minimum severity at OK. Optional Info Sets the minimum severity at Optional Info. Warning Sets the minimum severity at Warning. Required Info Sets the minimum severity at Required Info. **Error** Sets the minimum severity at **Error**. Calc Levels The Calc Levels page on the Main tab controls the order that streams, operations and flowsheets are calculated. For example, if you want a particular operation (Adjust) performed before another (Recycle); specify a lower Calculation level for the first operation. The operation with the lower Calculation Level is then calculated first. You can ignore operations from this view, and choose to see objects from sub flowsheets as well. You can sort the data by operation name or calculation level by right-clicking on the appropriate column and setting the sort options. Updates When objects (a reactor or flowsheet snippet or crude assay) are inserted in the case from the database, those objects can be linked to the database. 142 v Case Oil Synthesis Settings Use the Updates page to check for updates and synchronize your case with the database. Check... To... Database Updates Automatically Check for Updates from Enable Petro-SIM to notify you if newer versions of objects the Database After Recall are available from the database. Automatically Sync When Updates are Found Automatically synchronize the updates in the case. Crude Assay Database (CADB) Updates Automatically Check for Updates from Enable Petro-SIM to notify you if newer versions of CADB the Database After Recall objects are available from the database. Automatically Sync When Updates are Found Automatically synchronize the updates in the case. You can also add Notes. Licensing Tab The Licensing tab contains a list of all the available licenses used in Petro-SIM. All the licenses listed are not required to run the application. Only the ones that are checked . Depending on the type of Petro-SIM system purchased, all the available licenses may not be included. Case Oil Synthesis Settings The Case Oil Synthesis Settings view displays the physical methods and parameters used in the current case during oil synthesis. To view the case's settings, from the View tab, click Oil Synthesis. v 143 Chapter 3: Building a Simulation The Case Oil Synthesis Settings view displays the methods and parameters on these pages. Methods page Refer to Synthesis Methods and Physical Property Methods for details about specific methods. Parameters page Refer to Synthesis Parameters and Physical Property Parameters for details about specific parameters. Refer to Synthesis Calculation Hierarchy for information about how Petro-SIM manages the calculation precedence. 144 v Managing Cases Managing Cases Use the File menu options and commands to manage your cases, templates and files. l l l l l l l l l Create a New Simulation Case Open cases Save cases Save and print screenshots Print PFDs, Datasheets, and more Email cases, screenshots, movies, or links Save and load workspaces Close cases and Exit Petro-SIM Manage your Session Preferences Create a New Simulation Case 1. From the File menu, select New and then choose one of the following case types to open a new case: Select... To... Petro-SIM Refining Case Open a new case with a predefined component set and property package for a refinery simulation. Petro-SIM Production Case Open a new case with a predefined component set and property package for a production simulation SQLite Database Open a existing SQLite database file (*.kdb). Flaretot SQLite Database Open a existing SQLite Flaretot® database file (*.kdb). All Flaretot database files are SQLite database files. Case from scratch Open a new case with no predefined components. Template Open a new case as a template (*.tpl). You can define a component set and property package to save with the template. Column Open a new column flowsheet case. 2. Depending on which type of case you chose to open, you can begin building your simulation case. 3. When you are done, save the simulation case. v 145 Chapter 3: Building a Simulation Open Cases 1. From the File menu, select Open and then click the arrow to expand the view. By default, Petro-SIM displays your recently opened files. 2. Optionally, choose one of these buttons: l Cases – to view recent cases l Folders – to view recent folder locations. The number of recent cases remembered can be set in your Preferences. 3. To manage the files and file locations that appear. l Click next to the file/folder name to remove a file or folder from the list. l Click to pin and keep an item on the recently opened list regardless of how many files or folders get opened. 4. If you selected Cases, choose one of the following case types: l Case - opens your default folder location. l Sample Case – opens the Petro-SIM folder containing sample cases. l Database Case - opens the Available Database Simulation Cases view. l Template - opens the Petro-SIM Templates folder. l Column - opens the Petro-SIM Templates folder and displays column templates. l Cut/Copy/Paste - opens the Available Petro-SIM HFL Files view. l Open Case in Hold Mode - opens your default folder location where you can select a case which opens in Hold Mode. 5. Navigate to the location of the file you want to open, select it and then click Open. Use your CTRL or SHIFT key to select multiple cases. With multiple cases open, to cycle through each case you have open, press ALT+1 to view the first case, ALT+2 to view the second case and so on. ALT+0 opens the next case. HFL Files The HFL files are not full simulation case files, and do not contain case information on the Databook or Utilities. HFL files contain only information about the objects from the PFD. HFL files are more flexible than templates (*.tpl files). When you use the Cut/ Paste Objects (Export and Import) commands only the selected objects are copied and pasted, including fluid package information, without creating a new sub-flowsheet. l l l 146 v Save Objects to an HFL file Import HFL files Saving Cases to an HFL file Managing Cases Save Objects to an HFL file 1. Select the objects you want to export and then right-click the selected objects. 2. From the context menu, select Cut/Paste Objects and then Copy Objects to File (Export). 3. In the File Selection for Exporting dialog box, enter a File name for the HFL file and click Save. If the objects you have selected have streams attached, you will be asked if you want to export the streams as well. HFL files created in Petro-SIM 5.0 cannot be opened by previous versions of Petro-SIM. Import HFL files 1. In the PFD where you want to import an HFL file, right-click the background. 2. From the context menu, select Cut/Paste Objects and then Paste Objects from File (Import). v 147 Chapter 3: Building a Simulation 3. In the File Selection for Importing dialog box, select the HFL file you want to import and then click Open. The objects in the HFL file are pasted into the PFD. Saving Cases to an HFL file Instead of selecting all objects in your PFD and exporting to an HFL file, you can save an entire case as an HFL file. When you save the entire case, the main and all sub-flowsheets are saved as an HFL file. 1. From the File menu, select Save As. Refer also to Save Cases. 2. In the Save Simulation Case As dialog box, from the Save as type drop-down, choose Petro-SIM HFL Files. 3. Change the name in the File name field, if necessary and then click Save. HFL files can be opened directly (File menu, Open) rather than importing into an open case. When you open an HFL directly, a blank new case is created and the HFL file is imported into the new case. Save Cases If you are saving a case for the first time or if you chose to save the file to another file name or location, follow this procedure. 1. From the File menu, select one of these options: Select… To... Save Saves the current case. Save As Save the current case to a different file name or location. Save All Save all opened Petro-SIM cases. In the Save Simulation Cases view, select each file and then click Save or Save As to save each open case. Use the SHIFT or CTRL key to select two or more cases. 2. In the Save Simulation Save As view, navigate to and select the location where you want to save the case. 3. Enter a filename in the File name field. 148 v Managing Cases 4. Optionally, from the Save as type field, select the type of file you want to save it as: l Simulation case (*.ksc) – default file type l XML1 case (*.xml) - refer also to Petro-SIM XML. l HFL case (*.hfl) l Database (*.db) Petro-SIM supports Unicode file and directory names, meaning names can contain text and symbols from any language. 5. Optionally, click the Notes button and enter any relevant information for this file. The first line of the note file is displayed as a tooltip when you hover over the filename. Templates A template is a complete flowsheet that is stored with additional information on how to set up the flowsheet as a sub-flowsheet operation. Typically, templates represent a plant process module or a portion of a process module. The stored template can be read from a template file and installed as a complete sub-flowsheet operation numerous times and in any number of simulations. A template uses the file extensions *.tpl or *.hfl instead of the standard *.ksc file extension for Petro-SIM simulations. 1XML (Extensible Markup Language) is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. v 149 Chapter 3: Building a Simulation l l A combination of flowsheets can be in your template (i.e., a main flowsheet and one or more sub-flowsheets). More than one fluid package can be included in the template if they are associated with a flowsheet when you save the template. You cannot create a template from parts of a main flowsheet. Delete any unwanted streams and operations from the main flowsheet before saving it as a template. It can be saved with a different file name, preserving your original simulation case. For information on using a template in your simulation, refer to Installing a Template. To create a new template, begin with a main flowsheet as the base and follow one of these methods: Method 1 Use this method if you created a new case (not a new template) and you want to save it as a template, or if you have an existing case that you want to use as a template. You cannot create a template from an existing sub-flowsheet that is part of a larger simulation. 1. From the View tab, select Main Properties (or press CTRL+M). 2. In the Simulation Case property view, define the Name, Tag, and Standard Conditions, if required. 3. Select the Case Theme: l Petro-SIM Refining l Petro-SIM Production 4. Click Convert to Template. 5. Confirm whether you want to convert your case and save changes to the original simulation case. Method 2 To create a new template from a blank simulation, follow these steps: 150 v Managing Cases 1. From the File menu, select New and then Template. 2. In the Simulation Basis Manager, follow the standard procedure for building your simulation. 3. From the View tab, select Main Properties (or press CTRL+M). 4. In the Simulation Case property view, define the Name, Tag, and Standard Conditions, if required. 5. Select the Case Theme: l Petro-SIM Refining l Petro-SIM Production After you save the simulation as a template, a new Template tab is added to the Simulation Case property view. Refer to Template Information for more details. You can have multiple simulation cases in memory, so you can create a new template as part of your current session and then install it into your original simulation case. When you save the simulation, it is automatically saved as a template in the Templates directory with a *.tpl file extension. The path for the Templates directory is set in your Preferences. The default directory is \Template. HFL files, which are created using the Cut/Copy and Paste functions (accessible from the PFD), behave similarly to template files and can be created by selecting operation groups from within a simulation case. Template Information The template information for the flowsheet is accessed from the Simulation Case view. 1. From the View tab, select Main Properties (or press CTRL+M). When a simulation case is converted to a template or if you create a new template, a new Template tab is added to the Simulation Case property view. v 151 Chapter 3: Building a Simulation The Template tab contains the same information available on the property view of an installed sub-flowsheet operation as well as some additional information. 2. Enter the properties for the new template on these pages: l Connections l Variables With these extra parameters, the flowsheet can be treated as a black box and installed as a sub-flowsheet operation in the same way as a normal unit operation. Connections Page On the Connections page, all Feed and Product Stream connections are displayed. You can enter a Template Tag and select the Installed Simulation Basis. Feed and Product Streams All streams in the flowsheet template that are not completely connected, (i.e., are only a feed to a unit operation, or a product from a unit operation) are designated as Boundary Streams and appear in the appropriate group. Boundary Streams cannot be selected, but are automatically determined by Petro-SIM. When the template is installed in a flowsheet, you are connecting to these streams. 152 v Managing Cases A stream that appears on the Exported Connections tab does not necessarily have to be connected. For each stream appearing in either the Feed Stream or Product Stream matrices, you can specify the Boundary Label and Transfer Basis. l l A Boundary Label is used to describe the name of the feed and product connections. This is not the stream’s name, but the function of the streams (i.e., if using a numerical standard for stream numbering, the feed stream inside the template could be “1”, but its feed label could be “HP Feed”). This allows you to provide descriptive feed and product stream labels, much like the built-in unit operation property views used on their Connection tabs. By default, it assumes the name of its corresponding boundary stream in the template. The Transfer Basis is used for feed and product streams as they cross the flowsheet boundary. The Transfer Basis is significant only when the sub-flowsheet and parent flowsheet property packages are different. When there are differing fluid packages in the two flowsheets (parent and sub-flowsheet), you can specify what stream properties are used to calculate the stream on the other side of the boundary. The Transfer Basis is used to provide a consistent means of switching between the differing bases of the various property methods: Flash Type Description T-P Flash The pressure and temperature of the material stream are passed between flowsheets. A new vapour fraction is calculated. VF-T Flash The vapour fraction and temperature of the material stream are passed between flowsheets. A new pressure is calculated. VF-P Flash The vapour fraction and pressure of the material stream are passed between flowsheets. A new temperature is calculated. None Required No calculation is required for an energy stream. The heat flow is passed between flowsheets. Template Tag Flowsheet Tags are short names used by Petro-SIM to identify the flowsheet associated with a stream or operation when that flowsheet object is being viewed outside of its native flowsheet scope. The default Tag name for sub-flowsheet operations is TPL (for template). When more than one sub-flowsheet operation is installed, Petro-SIM ensures unique tag names by incrementing the numerical suffix similar to Petro-SIM auto-naming unit operations. They are v 153 Chapter 3: Building a Simulation numbered sequentially in the order in which they were installed. For example, if the first sub-flowsheet added to a simulation contained a stream called Comp Duty, it would appear as Comp Duty@TPL1 when viewed from the main flowsheet of the simulation. Installed Simulation Basis When a template is read into a simulation case, its associated fluid package is added to the list of fluid packages in the Simulation Basis Manager view. The Installed Simulation Basis gives the template builder the choice of using its own internal fluid package, or the same fluid package of the parent flowsheet where it is installed. This only affects what happens at the time the template is first installed. Once a template is installed, the resulting fluid package association can be overridden in the Simulation Basis Manager view at any time. Variables Page The Variables page of the Template tab is used to create and maintain the list of exported accessible variables. Although any information can be accessed inside the sub-flowsheet using the Multi Variable Navigator, this feature can target key process variables inside the sub-flowsheet and display their values on the property view. When the template is installed, you can view this information on the sub-flowsheet’s property view in the parent flowsheet. This is useful for “black box” treatment, as all the important specifications for the operation of the sub-flowsheet can be brought together and documented in this one location. You do not have to enter the sub-flowsheet environment to get the template “working” or adjusted to your needs. 1. To add variables to the template, click Add. 2. In the Add Variable to Case view, select the variable that you want to add to the template. 3. Optionally, enter a new Variable Description to override the previous description. 154 v Managing Cases When installing this template into another case, these variables appear on the Design Tab, Parameters page of the Sub-flowsheet property view. There is no difference between a template flowsheet and a normal flowsheet, except the additional information mentioned above and the use of different file extensions. A template flowsheet can be read in as the main flowsheet in a simulation case, if necessary. You get a warning message and the extra information is ignored. Installing a Template 1. To install a template into your flowsheet, begin by adding a sub-flowsheet to your simulation. 2. In the Sub-Flowsheet Option view, select Read an Existing Template. 3. Petro-SIM first looks in the Templates directory for available template files (*.tpl). Select the template that you want to use or navigate to the directory containing the template, and then select it. 4. Click Open. Petro-SIM installs any fluid packages from the template into the Simulation Basis Manager. The main flowsheet contained in the template is then installed as a new sub-flowsheet unit operation in your current flowsheet. If there are sub-flowsheets in the template, they are installed as sub-flowsheets below the new sub-flowsheet operation. After the flowsheet(s) are transferred into the simulation case, a fluid package is selected for the sub-flowsheet based on the Installed Fluid Package setting used in the template. After Petro-SIM finishes this process, sub-flowsheet Design Tab, Connections page is displayed. v 155 Chapter 3: Building a Simulation Printing in Petro-SIM You can print Petro-SIM cases, ranging from basic data to comprehensive summaries and graphics. Petro-SIM allows you to print several types of simulation case information based on two main types of data. Before printing, set your print setup options for both types of printing. Graphic Print the following types of graphical representations: l l l PFDs Plots, Strip charts, or Graphs Screenshots Report Print reports in grid or text formats: l l Datasheets Text Print PFDs Petro-SIM prints the PFD as it appears on the screen and prints to the printer that you have selected for the Graphic Printer setup in the Print Setup view. All objects, including streams, operations, text and PFD tables within the PFD view, are printed on a plain background. Petro-SIM does not print your background colour . To print the PFD, select one of these methods: l OR 156 v From the File menu, select Print and then choose Print. Managing Cases l Right-click the PFD background and from the context menu, select Print PFD, Print PFD. Refer also to l l l Print to SVG, WMF or EMF Formats Printer Setup Screenshots Print to SVG, WMF or EMF Formats PFDs can also be exported or printed to files in these formats: l l SVG - Scalable Vector Graphics format can be read by other applications such as Visio, Inkscape, etc. Unit operations are exported as groups of vector objects and can manipulated. SVG files use a different colour scheme than the Petro-SIM default. WMF - Windows Metafile format can be embedded and edited by applications such as Microsoft Word or Excel, as well as imported into applications such as Visio. WMF files use the same colour scheme as Petro-SIM. Strip charts, plots, and lab analysis graphs can be printed as plots or sent to this format: l EMF – Enhanced Metafile format is portable between applications and may contain both vector graphics and bitmap components. It acts in a similar manner to SVG files. v 157 Chapter 3: Building a Simulation 1. To print to one of these formats, right-click the background on the view you want printed. 2. From the context menu, select Print PFD and then one of these options: l Print to SVG File l Print to WMF File l Print to EMF File 3. In the Write File view, enter a File name and then click Save. If you select specific objects in a PFD, only those objects are printed to the file. Print Datasheets In Petro-SIM, you can print the Datasheets for the currently active view. For example, this could be a Workbook, Stream, Unit Operation, or Utility. 1. To print the Datasheet for your current view, right-click the title bar, and then choose Print Datasheet. Alternatively, select one or more objects in the PFD, and then from the Reports tab, click Print Datasheets. Depending on which view you selected, one of these views opens. Select Objects and Datablocks to Print 158 v Managing Cases Select Datablocks to Print 2. Check the objects and datablocks that you want to include from the respective Selected Objects and Available Datablocks areas. Some views cannot be printed (for example, the Reaction Package view) and the Select Datablocks view displays No Datasheets Available. 3. Optionally, to use the same print settings every time you print a Datasheet for the type of object you have selected, click Set Preferences. The Datablock selections are saved to your Session Preferences, Files tab, Datasheets, Reported Data page. 4. Optionally, click Format/Layout to set your page format, margins, and paper size. 5. To preview the results before printing to a printer, click Preview. 6. In the Report Preview, verify the Datasheet data is correct. v 159 Chapter 3: Building a Simulation 7. Click Print to print from the Report Preview. Otherwise, click Close to return to the Select Datablocks to Print view. 8. You can, optionally, choose to print a text file by checking the Text to File check box and then setting the text print options. 9. Click Print to print the Datasheet. Print Plots, Strip Charts, or Graphs To print plots, graphs, or strip charts, right-click the background and from the context menu, select Print and then choose: l l l 160 v Print Plot - sends the image to the locally set printer. Print to EMF File - prints the file to an Enhanced Metafile format (EMF) file which can be opened or imported by other applications. Print Setup - opens the Print Setup view where you can set your printer options. Managing Cases Refer also: l l l Print to SVG, WMF or EMF Formats Screenshots Strip Chart Printing Print Setup Petro-SIM provides settings for two different printer types: Printer Type For printing… Graphic Printer PFDs, Plots, Strip Charts, Lab Analysis Graphs, or Screenshots Report Printer Datasheets, Reports, or Text Each printer type can be set to a different printer. For example, you can set the Graphic Printer to be a colour, laser printer and the Report Printer to a black and white printer. Petro-SIM determines which printer is used based on what you are printing. 1. To set the printer options, from the File menu, select Print and then one of the following: l Graphic Printer l Report Printer You can also open the Print Setup view by right-clicking the PFD background and select Print PFD> Print Setup. v 161 Chapter 3: Building a Simulation 2. In the Print Setup view, set the following options: Set this option… Name To… Select the printer or type of printing from the drop-down list of available options. If you don’t see your local printer listed, you may need to install the printer. Contact your network support for assistance in setting up printers. For example, if you have a PDF writer application installed, you can select PDF. Properties Modify the printer’s settings such as page orientation, order, paper quality, colour settings, etc. These options are specific to the type of printer you select. Paper Select the page size from the drop-down list. Source Select Manually Feed if you want to manually feed paper to your printer. Orientation Select: l l Network Portrait Landscape Navigate to the printer location and select it. 3. Click OK when you are done setting the printer options. When you print, Petro-SIM automatically chooses the correct printer based on the type of object you are printing and uses the printer settings for that printer. Report Format and Layout When creating a report or printing a Datasheet, you can customize the page format, margins, and paper options. 162 v Managing Cases 1. In the Report Format and Layout view, check these options in the Format group. Check… To… Shading Add shading to the headers, footers and titles. Line Number Add line numbers to the left side of each page. Thick Borders Change the report borders to a thicker border than the other lines in the report. Indicate User Specified Indicate user-specified values in the Datasheet with an asterisk “*”. Start Datasheet on Print each Datasheet on a new page. New Page 2. In the Empty Text field, enter the characters you want displayed when an item has no value. The default is ---. 3. From the Unit Set drop-down, select the unit set you want your report to use. You can print using a different unit set than specified in your case. 4. Optionally, change the Page Margins and select the Paper Options. 5. To save the format selections as your Session Preferences, click Set Preferences button. The print selections are saved to your Session Preferences, Files tab, Datasheets page. 6. If your values are different from your preferences and you want to restore these to your default Session Preferences, click Use Preferences. Text to File When printing a Datasheet, you can optionally choose to print the data to a text file. v 163 Chapter 3: Building a Simulation 1. From the Select Datasheet to Print views, check the Text to File option. 2. If you want your text file to be text delimited, check Delimited. 3. Click the Format button to set the text delimiter options. Check… To… Text is Delimited Use a text delimiter for the data. If unchecked, the other options are not available. Title Description Visible Add a title that includes the name of the object and the tabs in the report. Header Field Visible Add a header that includes the company information and the date that the file was created. Footer Field Visible Add a footer that includes the Petro-SIM version and build number. Fields Padded for Add spaces between each field to align the fields. Alignment Disable Column Wrapping Disable column wrapping so that text runs past the edge of the page and does not wrap to the next line. Empty Text Specify what value to display when there's no value available. The default is <blank>. Delimiter Specify the delimiter. The default is a comma or semicolon depending on the local decimal separator. 4. From the Unit Set drop-down, select the unit set you want your report to use. You can print using a different unit set than specified in your case. 5. To save the format selections as your Session Preferences, click Set Preferences. The print selections are saved to your Session Preferences (Files tab, Datasheets, Text Format). 164 v Managing Cases 6. If your values are different from your preferences and you want to restore these to your default Session Preferences, click Use Preferences. Screenshots In Petro-SIM, you can save a screen image (screenshot) of any view. Screenshots can be printed, copied to your clipboard, or saved to a file. 1. To capture a screenshot of your current view, from the File menu, click Screenshot and then choose one of these options: Choose… To… Active Window to Printer Creates a screen capture of your active window and sends it to the printer. Active Window to File and Clipboard Creates a screen capture of your active window and saves it to your clipboard and to a PNG file. The file is saved to the location for Pictures set in your Preferences (Files, Locations). Keyboard Shortcut: Press CTRL+L. Active Window to Clipboard Creates a screen capture of your active window and saves it to your clipboard. Use Paste (CTRL+V) to paste it to another application. Entire Window to File Creates a screen capture of your entire Petro-SIM window to a PNG file. The file is saved to the location for Pictures set in your Preferences (Files, Locations). Entire Window to Clipboard Creates a screen capture of your entire Petro-SIM window to your clipboard. Use Paste (CTRL+V) to paste it to another application. 2. If you captured the screenshot to your clipboard, you can paste it to another application. If you saved it as file, you can open it or import it into another application. You can also Email a screenshot. Email Use your Email application to send copies of your case, images of a Petro-SIM screen, PetroSIM movies, or a link to your case. v 165 Chapter 3: Building a Simulation Choose… To… Email Case Open a new email message and attaches a copy of your active case. As a precaution, a preferences file (*.PRF) is automatically attached that contains the settings for the simulation. This file can be removed or renamed if your email system considers the extension to be unsafe. If your case has been modified but has not been saved, Petro-SIM saves a temporary copy it then uses to attached to the email to ensure your latest changes are sent. Email Screenshot Open a new email message and attaches a screenshot of your active window as a PNG file (PNG files compress well and are lossless). Email Both Open a new email message and attaches a screenshot of your active window and a copy of your active case with a preferences file (3 files). Zip and Email Movie Open a Browse for Movie file window to your default location for Videos. Select the movie you want to send. Petro-SIM compresses the file and attaches it to a new email message. Use the Petro-SIM movie recorder to record movies you want to send to Petro-SIM Support. Email Link to Case If you save your case to a shared directory on your PC or to a virtual directory on the Internet, send the link to email recipients. Petro-SIM generates a link as a *.krl file to the location of your case and attaches it to a new email message. About Link Files Link files (*.krl) are just text files that can be edited using Notepad. They are created using one of the following methods: l l Email - select the Email Link to Case option. Database Connection view - right-click the matrix and select Email Connection Information. The format used in the link files is as follows: OpenFiles includes the full path and file name. 166 v Managing Cases ConnectToDatabase includes the connection string. LoadPreferenceFile must be followed by the file name of a preference file to load. ImportAssays must be followed by one or more assays. One assay per line. For each assay an XML file name can be given. If the assays are to be imported from a database, then the assay name must be given and a file extension of .db must be appended to the assay name. Link files can contain any number of blank lines. Blank lines are ignored, but a blank line terminates any list of files. It can also contain comments, but each comment line must start with // or ## or <!--. It is possible to use the substring “(@@1)” in a file name as “(@@1)\File1.ksc”. When the link file is open, the (@@1) gets replaced with the path to the link file. This way several files in the same directory as the KRL file can be opened. Workspace The Workspace commands can help you save and reload specific workspace views within a case. You can open one or more views that you are working with and then save that configuration as a Workspace. When you reload the case and want to open that same set of views, you only need to load the workspace. Save Workspace You can save different Workspace arrangements in a Petro-SIM case. The Workspace is a specific organization of views for the current case. For example, create an arrangement of views that has the PFD and the Workbook. You can name each arrangement individually to access it any time. v 167 Chapter 3: Building a Simulation This only affects the way the various views are arranged and has no effect on the calculation status. After changes are made to the Desktop arrangement, re-load a saved arrangement to open the view layout. 1. Within your case, open and position the views you want to save as your workspace configuration. For example, you may want to view all the stream properties. You can have as many views open as you want. 2. To save this configuration, from the File menu, select Workspace and then Save Workspace. 3. In the Save Workspace view, select <Most Recent Workspace> and enter a name in the Save Workspace As: field. Petro-SIM remembers the views and position of those views as part of each Workspace that you save for that case. Load Workspace You can use the Load Workspace command to load a different set of views in your current case, or you can use it to open another case with a specific set of views. 1. To load a saved workspace, from the File menu, select Workspace and then Load Workspace. 2. In the Load Workspace view, select the workspace view that you want to load. 168 v Managing Cases 3. Ensure that Save when switching is checked to save the case before switching workspaces. 4. Click Load to load the workspace configuration. Petro-SIM saves the case, closes all previous views you have open and then loads the workspace. Close Cases and Exit Petro-SIM Use the Close button on the case window to close the case and the Exit button to exit PetroSIM. If your case was not saved before selecting Close or Exit, a message displays prompting you to save the case. Hover your mouse over the icon to display details about the current active environment and the case standard conditions. Click... To... Display the Petro-SIM online help file. Display the About Petro-SIM view that shows the current version information. Open the Database Connection view where you can connect to or disconnect from a database. Minimize or maximize the ribbon. or v 169 Chapter 3: Building a Simulation Unit Operations The components that make up Petro-SIM have produced a powerful approach to steady state process modelling. At a fundamental level, the comprehensive selection of operations and property methods let you model a wide range of processes with confidence. Perhaps even more important is how the Petro-SIM approach to modelling maximizes your return on simulation time through increased process understanding. The key to this last fact is the event-driven operation. By using a degrees of freedom approach, calculations in Petro-SIM are performed automatically. Petro-SIM performs calculations as soon as unit operations and property packages have enough required information. To learn more about unit operations and how to install them in your PFD, refer to: l l l Unit Operation Property View Installing Operations Setting Up Reactors in Petro-SIM Any results, including passing partial information when a complete calculation cannot be performed, are propagated bi-directionally throughout the flowsheet. This means that you can start your simulation in any location, using the available information to its greatest advantage. Since results are available immediately, including as calculations are being performed, you gain the greatest understanding of each individual aspect of your process. The multi-flowsheet architecture of Petro-SIM is important to this overall approach to modelling. Although Petro-SIM has been designed to allow the use of multiple property packages and the creation of pre-built templates, the greatest advantage of multi-flowsheeting is that it provides an effective way to organize large processes. By breaking flowsheets into smaller components, you can isolate any aspect for detailed analysis. Each of these sub-processes is part of the overall simulation, automatically calculating like any other operation. The design of the Petro-SIM interface is consistent, if not integral, with this approach to modelling. Access to information is the most important aspect of successful modelling, with accuracy and capabilities accepted as fundamental requirements. Not only can you access whatever information you need when you need it, but the same information can be displayed simultaneously in a variety of locations. Just as there is no standardized way to build a model, there is no unique way to look at results. Petro-SIM uses a variety of methods to display process information - individual property views, the PFD, workbook, databook, graphical performance profiles, and tabular summaries. Not only are all of these display types simultaneously available, but through the object-oriented design, every piece of displayed information is automatically updated whenever conditions change. The inherent flexibility of Petro-SIM allows for the use of third-party design options and custombuilt unit operations. These can be linked to Petro-SIM through OLE extensibility. 170 v Unit Operations Integrated into the steady state modelling is multi-variable optimization. Once you have reached a converged solution, you can construct virtually any objective function with the optimizer. There are five available solution algorithms for both unconstrained and constrained optimization problems, with an automatic backup mechanism when the flowsheet moves into a region of non-convergence. In modelling operations, Petro-SIM uses a degrees of freedom approach that increases the flexibility with which solutions are obtained. For most operations, you are not constrained to provide information in a specific order, or even to provide a specific set of information. As you provide information to the operation, Petro-SIM calculates any unknowns that can be determined based on what you have entered. For instance, consider the pump operation. If you provide a fully-defined inlet stream to the pump, Petro-SIM immediately passes the composition and flow to the outlet. If you then provide a percent efficiency and pressure rise, the outlet and energy streams are fully defined. If the flowrate of the inlet stream is undefined, Petro-SIM cannot calculate any outlet conditions until you provide three parameters, such as the efficiency, pressure rise, and work. In the case of the pump operation, there are three degrees of freedom, thus, three parameters are required to fully define the outlet stream. v 171 Chapter 3: Building a Simulation Unit Operation Property View Although each unit operation differs in functionality and operation, the unit operation property view remains fairly consistent in its overall appearance. . A typical property view for a unit operation, such as the Naphtha Reformer example below, contains one or more tabs, and each tab may contain one or more pages. Most unit operation property views contain these components: Title Bar - shows the name of the unit operation. You can modify the name at any time. Tabs - may contain one or more pages that you can define properties or view results. Some typical tabs include: l l l 172 v Design - is used to define the feed and product streams to the unit operation. Other parameters such as pressure drop, heat flow, and solving method are also specified on pages of this tab. It usually contains a User Variables page and a Notes page. Worksheet - summarizes the conditions, properties, composition, and pressure flow values of the streams entering and exiting the unit operation. This tab is available on most unit operations. Results - used to display the solver results. Unit Operations Pages - are where you enter properties, parameters, and conditions. The Design tab contains two common pages: l l User Variables - Use this page to attach user variables to your operations. Notes - Use this page to include relevant information or attachments to the operation. Status bar - shows the status of the operation solver. Image - displays a graphical representation of the unit operation, as well as input and output connections. Delete - click to remove the unit operation from the simulation. Ignored - check to ignore the unit operation during calculations. Refer also to Solver Active/Holding. Worksheet Tab The Worksheet tab summarizes the parameter information for the streams attached to the unit operation. l Select the Ignored check box if you want the solver to ignore calculations for the unit operation in the PFD. The Worksheet tab contains these pages: Conditions Displays the condition properties for each stream attached to the unit operation. v 173 Chapter 3: Building a Simulation l l l Hover over a value in the grid to display that value converted to other units and the source of calculation. The tooltips display if you have the Show Tooltips option selected in your Preferences. You can, optionally, modify certain parameters (displayed blue) directly in the grid or double-click the value to open the Streams Properties view. Right-click a value to display a context menu with more edit and display options. Properties Displays the property correlations of the inlet and outlet streams. l l Hover over a value in the grid to display that value converted to other units. The tooltips display if you have the Show Tooltips option selected in your Preferences. Right-click a value to display a context menu with more edit and display options. Composition Displays the composition of each stream attached to the unit operation. 174 v Unit Operations Extended Displays the extended composition parameters only if the composition of the streams contains extended composition parameters. l l l Click the + or — sign to expand or collapse the parameters Double-click a value to open the Streams Properties view. Right-click a value to display a context menu with more edit and display options. PF Specs Displays the pressure flow specifications for the streams if you have set to always show dynamics information in your Preferences. v 175 Chapter 3: Building a Simulation l l l Hover over a value in the grid to display that value converted to other units and the source of calculation. The tooltips display if you have the Show Tooltips option selected in your Preferences. Use the activation check boxes to dynamically enable or disable the parameter in the PFD. Right-click a value to display a context menu with more edit and display options. Notes Many views in Petro-SIM contain a Notes page in which you can include details about the object or process. The Notes page lets you attach supporting documents such as spreadsheets, PDFs, equations, or images, to the operation. Petro-SIM stores attached files with the simulation. Use the editing tools at the top of the page to format the contents. Click 176 v to attach a file to the case. Unit Operations To find all notes associated with the case, use the Search tool, Advanced option. To view the Case Notes, from the View tab, click Case Notes. Solver Active or Hold By default, the Solver is active enabling Petro-SIM to calculate and control the degrees of freedom as you enter information. Turning the Solver off is useful for making multiple changes to a flowsheet. When you inherit a case, if your case is not solving, check if the solver is Active before troubleshooting. From the Home tab, press Hold to activate/deactivate (toggle) the Solver in Hold mode. From the Home tab, press mode. Active to activate/deactivate (toggle) the Solver in Active You can also press F8 to toggle from Hold to Active and vice versa or double-click the bottom left corner of the Status bar. Petro-SIM places the Solver in Hold in the following situations: l l l When an inconsistency error occurs. After linking in calibration factors from a Refinery model. At any time (press F8) after changes are made in the Basis Environment. Installing Operations Unit Operations can be installed into the PFD flowsheets in several ways. The operations available depend on where you are working (main flowsheet, template sub-flowsheet, or column sub-flowsheet). If you are in the main flowsheet or template environments, all operations are available, except those associated specifically with the column, such as reboilers and condensers. A smaller set of operations are available within the column sub-flowsheet. When working in steady-state mode, these unit operations are available in these categories from the Operations palette (press F4 to view the operations palette): l l l l General Separation Logical Refining v 177 Chapter 3: Building a Simulation It is also recommended that you review the information for Streams as they are the means of transferring process information between unit operations. Setting Up Reactors in Petro-SIM Petro-SIM provides several unit operations that simulate reactions between library components: l l l l l Continuously Stirred Tank Reactor (CSTR) Plug Flow Reactor (PFR) Gibbs Reactor Equilibrium Reactor Conversion Reactor With the exception of the Plug Flow Reactor (PFR), these reactor operations share the same basic property view. The primary differences are the functions of the reaction type (conversion, kinetic, equilibrium, heterogeneous catalytic, or simple rate) associated with each reactor. As opposed to a separator or general reactor with an attached reaction set, specific reactor operations can only support one particular reaction type. For instance, a Conversion Reactor only functions properly with conversion reactions attached. If you try to attach an Equilibrium or a Kinetic reaction to a Conversion Reactor, an error message displays. The GIBBS Reactor is unique in that it can function with or without a reaction set. You have a great deal of flexibility in defining and grouping reactions. You can: l l l Define the reactions inside the Basis Manager: group them into a set and then attach the set to your reactor. Create reactions in the Reaction Package in the main flowsheet: group them into a set, and attach the set to the reactor. Create reactions and reaction sets in the Basis Environment and make changes in the Main Environment's Reaction Package. Regardless of the approach, the reactions you define are visible to the entire flowsheet, that is, a reaction set can be attached to more than one reactor. There are some subtleties of which you must be aware. When you make a modification to a reaction via a reactor, the change is only seen locally in that particular reactor. Modifications made to a reaction in the Basis Environment or in the reaction package are automatically reflected in every reactor using the reaction set, provided you have not made changes locally. Local changes are always retained. To override local changes and return the global parameters to a reaction, press the Delete key when the cursor is in the cell that contains the local change. Refer to the Reactions and Reaction Sets for details. 178 v Chapter 4: Simulation Basis Environment The Simulation Basis Manager helps you create, define and modify fluid packages used by the simulation’s flowsheet. A fluid package must contain a property package. You can add components, hypothetical components, reactions, interaction parameters, and more. You enter the Simulation Basis Environment automatically when you create a new case from scratch. The pre-built Petro-SIM Production and Petro-SIM Refining starter cases already have the necessary information defined. To enter the Simulation Basis environment from any flowsheet, from the Home tab, click Basis (or press CTRL+B). The Simulation Basis Manager view displays. A simulation must have at least one fluid package, but may contain multiple fluid packages. in addition, each object and flowsheet can have its own fluid package. Use the Simulation Basis Manager to create and manipulate fluid packages and additional simulation properties: v 179 Chapter 4: Simulation Basis Environment l l l l l l l Fluid Pkgs Components Hypotheticals Oil Manager Reactions Component Maps User Properties Fluid Packages The Simulation Basis Manager Fluid Pkgs tab is where all information pertaining to pure component flash and physical property calculations is contained. You must define at least one fluid package before entering the PFD/Simulation environment. When you create a new case, PetroSIM displays the Simulation Basis Manager Fluid Pkgs tab where you can create or import fluid packages for the simulation. Defining all the required fluid package information in a single location provides four key advantages: l l l l All associated information is defined in a single location, allowing for easy creation and modification of the information. Fluid Packages can be exported and imported as completely defined packages for use in any simulation. Fluid Packages can be cloned, which simplifies the task of making small changes to a complex Fluid Package. Multiple Fluid Packages can be used in the same simulation. They are all defined in the Simulation Basis Manager. Individual components are not added in the Fluid Pkgs tab, but are handled independently through the Components tab where sets of chemical components being modelled may be retrieved and manipulated. 180 v Fluid Packages Current Fluid Packages The following buttons help you create and manage all fluid packages for the current case. Select... To... View View existing fluid packages in the Fluid Package property view. Add Add a new fluid package to the case in the Fluid Package property view. Delete Delete a selected fluid package from the case. When deleting a fluid package, Petro-SIM asks you to verify that you want to delete the package. You must have at least one fluid package for your case at all times. Copy Copy a selected fluid package and paste a new fluid package in the Current Fluid Package group. The new fluid package is identical, except for the name. Import Import a pre-defined fluid package from disk. Fluid packages have the file extension .fpk. Export Export a selected fluid package (*.fpk) to disk. The exported fluid package can be imported into other cases from their Fluid Pkgs tab in the Simulation Basis Manager. Flowsheet - Fluid Pkg Associations The Flowsheet - Fluid Pkg Associations group lists each flowsheet in the current simulation along with its associated fluid package. To change the associations between flowsheets and which fluid package to use in this location, select the fluid package from the Fluid Pkg To Use drop-down list column. v 181 Chapter 4: Simulation Basis Environment You can also specify a default fluid package by selecting a package in the Default Fluid Pkg drop-down list. Petro-SIM automatically assigns the Default Fluid Package to each unit operation, sub-flowsheet, or column. Changing the default fluid package only changes those fluid packages that are currently set to use the default fluid package. Any operation or stream that is not set to the default fluid package is not modified. Selecting an alternate fluid package from the Simulation Basis Manager view allows you to transition or switch between fluid packages anywhere in the flowsheet with the addition of the stream cutter unit operation. Fluid Package Property View When you choose to add or modify a fluid package from the Fluid Pkgs tab on the Simulation Basis Manager, the Fluid Package property view displays. Enter or view the Fluid Package properties on these tabs: l l l l 182 v Set Up - Select a property package and associated properties for the fluid package. Parameters - Depending on the property package selected, supply additional information based on the selected components. Binary Coeffs (Binary Coefficients) - Specify the binary coefficients, if necessary. As an alternative to supplying binaries, you may want to have estimates made for the selected components. StabTest (Stability Test) - If necessary, instruct Petro-SIM how to perform Phase Stability tests as part of the flash calculations. Fluid Packages l l l l Rxns (Reactions) - Define any reactions and reaction sets for the fluid package or access the Reaction Manager. Tabular - Access the Tabular Package for the equation-based representation of targeted properties. Notes - Supply additional descriptive notes for the new Fluid Package. Phase Order - Sort phases based on their Type and Phase Density. Select the component list for the Fluid Packages from the Component List Selection dropdown list. For more details about selecting Component Lists, refer to Component List View. Set Up Use the Fluid Package Set Up tab to define the property package for each fluid package in your simulation. Select the Component List Select a Component List to associate with the current Fluid Package from the Component List Selection drop-down list. Component Lists are stored in the Components Manager and may contain traditional, hypothetical and electrolyte components. Click View to open the Components List where you can view or modify the components for the fluid package. If you switch between property packages and any components that are incompatible or not recommended for use with the current property package, the Components Incompatible with Property Package or Components Not Recommended for Property Package views lists the components that are incompatible or not recommended. Select another package or delete the components. v 183 Chapter 4: Simulation Basis Environment Click Edit Properties to view or modify the components in the Fluid Package. Select the Property Package Select the property package type from the Property Package Filter group, and then choose the package from the available property packages. The information that is displayed depends on the selected property package. For more information about the options displayed for your selected property package, refer to these property package types: Choose... To choose from these property packages... All Types All property packages for all types listed below. Multiflash Multiflash: l l l l EOSs 184 v CPA GERG 2008 MFL File RKSA Equations of state (EOS): Fluid Packages Choose... To choose from these property packages... l l l l l l l l l l Activity Models Liquid activity models: l l l l l l l l Chao Seader Models GCEOS Kabadi Danner Lee-Kesler Plöcker MBWR Peng Robinson PRSV Sour SRK Sour PR SRK Zudkevitch Joffee Chien Null Extended NRTL General NRTL Margules NRTL UNIQUAC Van Laar Wilson Chao Seader based semi-empirical methods:. v 185 Chapter 4: Simulation Basis Environment Choose... To choose from these property packages... l l Vapour Press Models Vapour pressure k-value models: l l l Miscellaneous Types 186 v Chao Seader Grayson Streed Antoine Braun K10 Esso Tabular Models that do not fit into any of the above categories: Fluid Packages Choose... To choose from these property packages... l l l l l Amine Pkg ASME Steam CAPE-OPEN 1.1 MBWR NBS Steam For detailed information about the property packages available in Petro-SIM, refer to Property Methods. Multiflash Petro-SIM offers a number of property methods that originate from Infochem’s Multiflash™ product. Select one of the following Property Packages and then configure the options on the Parameters tab. Multiflash Description CPA The CPA model is the recommended model for hydrate calculations, or other cases including water, methanol, ethanol, MEG, DEG, TEG, and salts. For other (non-polar) components, CPA reduces to the RKSA EOS. Refer to Cubic Plus Association (CPA). GERG 2008 Applications of the model include: l l l l l l l acid gas injection natural gas pipelines and processes CO transport and carbon sequestration 2 water/steam systems air instrument calibration multi-phase meters The model performs best for mixtures that do not involve strong specific interactions and for any of the pure substances in the list above. For mixtures, appropriate binary interaction parameters are needed for good accuracy. BIPs are included for the following components: l l l CO 2 H S 2 Methane v 187 Chapter 4: Simulation Basis Environment Multiflash Description l l l l l Ethane Propane Butane Pentane Water The mixture model is applicable to systems that do not contain free water. The GERG 2008 model is a well-verified standard and is probably the best model for natural gas mixtures containing the components listed above. Refer to GERG 2008. MFL File Import any existing MFL file from Infochem’s Multiflash into Petro-SIM for use as a property package. Refer to MFL File. RKSA The Redlich-Kwong-Soave (RKSA) equations and their variants are examples of simple cubic equations of state. The simple cubic equations of state are widely used in engineering calculations. They require limited pure component data and are robust and efficient. Both PR and RKS are used in gas-processing, refinery and petrochemical applications. They usually give broadly similar results, although if one model has been fitted to experimental data and there are no interaction parameters for the other, then the optimized model is always preferable. There is some evidence that RKS gives better fugacities and PR better volumes (densities) but both can be improved if the Peneloux correction is used. Select one of the following options: l l RKS (Advanced) model set is recommended because it uses the Peneloux correction, fits the EOS parameters to match the vapour pressure, and uses the Van Der Waals 1-fluid mixing rules. RKSA (Infochem) can be used as part of the hydrate model and provides extra flexibility to represent the highly non-ideal aqueous system. It does, however, require suitable BIPs for such systems. Refer to Redlich-Kwong-Soave (RKS). Equation of State (EOS) For oil, gas and petrochemical applications, the Peng-Robinson equation of state (EOS)model is generally the recommended property package. It is customized to be accurate for a variety of 188 v Fluid Packages systems over a wide range of conditions. It rigorously solves most single phase, 2-phase, and 3phase systems with a high degree of efficiency and reliability. All EOS methods and their specific applications are described below: EOS Description GCEOS This model allows you to define and implement your own generalized cubic equation of state including mixing rules and volume translation. Select the Enthalpy method. Kabadi Danner This model is a modification of the original SRK EOS, enhanced to improve the vapour liquid-liquid equilibria calculations for water-hydrocarbon systems, particularly in dilute regions. Select the Enthalpy method. Lee-Kesler Plöcker This model is the most accurate general method for non-polar substances and mixtures. MBWR This is a modified version of the original Benedict/Webb/Rubin equation. This 32-term equation of state model is applicable for only a specific set of components and operating conditions. Peng-Robinson This model is ideal for VLE calculations as well as calculating liquid densities for hydrocarbon systems. Several enhancements to the original PR model were made to extend its range of applicability and to improve its predictions for some non-ideal systems. in situations where highly non-ideal systems are encountered, the use of Activity Models is recommended. Select the Enthalpy method, Peng Robinson options, and the density specifications. PRSV This is a two-fold modification of the PR equation of state that extends the application of the original PR method for moderately non-ideal systems. Select the Enthalpy method. Sour SRK Combines the Soave Redlich Kwong and Wilson's API-Sour Model. Select the Enthalpy method and the density specifications. Sour PR Combines the PR equation of state and Wilson's API-Sour Model for handling sour water systems. Select the Enthalpy method and the density specifications. SRK In many cases, it provides comparable results to PR, but its range of application is significantly more limited. This method is not as reliable for nonideal systems. v 189 Chapter 4: Simulation Basis Environment EOS Description Select the Enthalpy method and the density specifications. Zudkevitch Joffee Modification of the Redlich Kwong EOS. This model has been enhanced for better prediction of vapour-liquid equilibria for hydrocarbon systems and systems containing Hydrogen. EOS Enthalpy Method Specification The Lee-Kesler Plöcker (LKP) and Zudkevitch Joffee (ZJ) property packages both use the LeeKesler enthalpy method. You cannot change the enthalpy method for either of these EOSs. With all other EOS property packages,choose one of the following enthalpy methods: Select this Enthalpy Method To... Equation of State Use the Equation of State enthalpy method. Lee-Kesler Use the Lee-Kesler method for the calculation of enthalpies. This option results in a combined Property Package, employing the appropriate EOS for vapourliquid equilibrium calculations and the Lee-Kesler equation for the calculation of enthalpies and entropies. This method yields comparable results to Petro-SIM standard EOSs and has identical ranges of applicability. Lee-Kesler enthalpies may be slightly more accurate for heavy hydrocarbon systems, but require more computer resources because a separate model must be solved. Peng Robinson Options The Peng Robinson options are only available when the Peng Robinson property package is selected. Select this option 190 v To use... Petro-SIM The Petro-SIM PR EOS that is similar to the PR EOS with several enhancements to the original PR equation. It extends its range of applicability and better represents the VLE of complex systems. Standard The standard Peng Robinson (1976) EOS, which is a modification of the RK Fluid Packages Select this option To use... equation to better represent the VLE of natural gas systems accurately. Density Specifications The Use EOS Density and Smooth Liquid Density check boxes affect the Peng Robinson, Sour PR , SRK,and Sour SRK property packages. These property packages, by default, use the Costald liquid density model. This method only applies when the reduced temperature (Tr) is less than unity. When the reduced temperature exceeds unity, it switches to the EOS liquid density. Therefore, at Tr=1 there is a sharp change (discontinuity) in the liquid density that may cause problems. By default, new cases have the density smoothing option selected and EOS density not selected, which is the recommended option. By default, or if the smoothing option is selected, Petro-SIM interpolates the liquid densities from Tr=0.95 to Tr=1.0, giving a smooth transition. Costald typically gives better liquid densities and smoothing near Tr = 1 is common. The densities differ if the option is not selected. Activity Models Although Equation of State models are very reliable in predicting the properties of most hydrocarbon-based fluids over a wide range of operating conditions, their application is limited primarily to non-polar or slightly polar components. Highly non-ideal systems are best modelled using Activity Models. Select from the following Activity Model property packages: Activity Model Description Chien Null Provides a consistent framework for applying existing Activity Models on a binary by binary basis. It allows you to select the best Activity Model for each pair in your case. Extended NRTL This variation of the NRTL model allows you to input values for the Aij, Bij, Cij, Alp1ij and Alp2ij parameters used in defining the component activity coefficients. Apply this model to systems: l l General NRTL with a wide boiling point range between components. where you require simultaneous solution of VLE and LLE and there exists a wide boiling point range or concentration range between components. This variation of the NRTL model allows you to select the equation format for equation parameters: τ and α Apply this model to systems: v 191 Chapter 4: Simulation Basis Environment Activity Model Description l l with a wide boiling point range between components. where you require simultaneous solution of VLE and LLE and there exists a wide boiling point or concentration range between components. Margules This was the first Gibbs excess energy representation developed. The equation does not have any theoretical basis, but is useful for quick estimates and data interpolation. NRTL This is an extension of the Wilson equation. It uses statistical mechanics and the liquid cell theory to represent the liquid structure. It is capable of representing VLE, LLE and VLLE phase behaviour. UNIQUAC Uses statistical mechanics and the quasi-chemical theory of Guggenheim to represent the liquid structure. The equation is capable of representing LLE, VLE and VLLE with accuracy comparable to the NRTL equation, but without the need for a non-randomness factor. van Laar This equation fits many systems quite well, particularly for LLE component distributions. It can be used for systems that exhibit positive or negative deviations from Raoult's Law, it cannot predict maxima or minima in the activity coefficient. Therefore it generally performs poorly for systems with halogenated hydrocarbons and alcohols. Wilson First activity coefficient equation to use the local composition model to derive the Gibbs Excess energy expression. It offers a thermodynamically consistent approach to predicting multi component behaviour from regressed binary equilibrium data. However the Wilson model cannot be used for systems with two liquid phases. Activity Model Specifications The Activity Model Specifications group enables you to specify the method to be used for solving the vapour phase. Activity Models only perform calculations for the liquid phase. 192 v Fluid Packages 1. Select an appropriate Vapour Model for your fluid package from the drop-down list. Select... To... Ideal Apply the Petro-SIM default for cases in which you are operating at low or moderate pressures. RK Apply the generalized Redlich Kwong cubic equation of state that is based on reduced temperature and reduced pressure and is generally applicable to all gases. Virial Better model the vapour phase fugacities of systems that display strong vapour phase interactions. Typically this occurs in systems containing carboxylic acids or other compounds that have the tendency to form stable hydrogen bonds in the vapour phase. PR Use the Peng Robinson EOS to model the vapour phase. Use this option for all situations to which PR is applicable. SRK Use the Soave Redlich Kwong EOS to model the vapour phase. Use this option for all situations to which SRK is applicable. 2. Enter a temperature in the UNIFAC Estimation Temp field (and select the units). This temperature is used to estimate interaction parameters using the UNIFAC method. By default, the temperature is 25°C, although better results are achieved if you select a temperature that is closer to your anticipated operating conditions. 3. Leave the Use Poynting Correction check box checked to activate the Poynting correction factor. The correction factor is only available for vapour phase models. The correction factor uses each component’s molar volume (liquid phase) in the calculation of the overall compressibility factor. Chao Seader Models The Chao Seader and Grayson Streed methods are older, semi-empirical methods. The Grayson Streed correlation is an extension of the Chao Seader method with special emphasis on hydrogen. Only the equilibrium data produced by these correlations is used by Petro-SIM. The Lee-Kesler method is used for liquid and vapour enthalpies and entropies. Model Description Chao Seader Use this method for heavy hydrocarbons, where the pressure is less than 10342 kPa (1500 psia) and temperatures range between -18 and 260°C (0500°F). Grayson Streed Recommended for simulating heavy hydrocarbon systems with a high hydrogen content. v 193 Chapter 4: Simulation Basis Environment Vapour Pressure Models Vapour Pressure K-value models may be used for ideal mixtures at low pressures. Ideal mixtures include hydrocarbon systems and mixtures such as ketones and alcohols, where the liquid phase behaviour is approximately ideal. The models may also be used as first approximations for non-ideal systems. The following vapour pressure models are available: Vapour Pressure Models Description Antoine This model is applicable for low pressure systems that behave ideally. Braun K10 This model is strictly applicable to heavy hydrocarbon systems at low pressures. The model employs the Braun convergence pressure method where, given the normal boiling point of a component, the K-value is calculated at system temperature and 10 psia (68.95 kPa). Esso Tabular This model is applicable to hydrocarbon systems at low pressures. The model employs a modification of the Maxwell-Bonnel vapour pressure model. Miscellaneous Types The Miscellaneous Types group contains property packages that are unique and do not fit into any of the other property package groups. Property Package Description Amine Pkg Schlumberger’s AMSIM™ package. ASME Steam Restricted to a single component, H O. Uses the ASME 1967 Steam Tables. 2 Link to any CAPE-OPEN thermo packages (including any Multiflash CAPEOPEN property packages). CAPE-OPEN 1.1 MBWR This is a modified version of the original Benedict/Webb/Rubin equation. This 32-term equation of state model is applicable for only a specific set of components and operating conditions. NBS Steam Restricted to a single component, H O. Uses the NBS 1984 Steam Tables. 2 Parameters The Fluid Packages Parameters tab contains information and options for the following property packages. 194 v Fluid Packages l l l l l l l l l Multiflash GCEOS Kabadi Danner Peng-Robinson Stryjek Vera (PRSV) Zudkevitch Joffee Chien Null Wilson Chao Seader and Grayson Streed Antoine Property packages not listed above have no parameters. Multiflash When using a Multiflash property package, the Parameters tab lists the options available to modify that property package. You can, optionally, turn off phase detection calculations for Hydrate phases I and II and Freeze Out calculations for Solid Ice and Mercury. All Multiflash property packages always detect Vapour, Liquid1, Liquid2, Aqueous, and Liquid Mercury phases where present. Select the options in the Transport Property Methods group: Viscosity SuperTRAPP The SuperTRAPP method is a predictive, extended corresponding-states model that uses propane as a reference fluid. It can predict the viscosity of petroleum fluids and well-defined components over the entire phase range from the dilute gas to the dense fluid. The Infochem implementation of SuperTRAPP model includes modification to ensure that the viscosity of aqueous solutions of methanol, ethanol MEG, DEG, and TEG or salts and ions are predicted reasonably well. Overall the SuperTRAPP method is the most versatile method for viscosity predictions and its performance is generally better than the other methods available in Multiflash. We recommend this method for oil and gas applications. It is the default viscosity method for use with equations of state. Refer to The corresponding-states principle: Dense Fluids1 in Transport properties of Fluids: Their correlation, Prediction and Estimation2 . 1Huber, M. L. & Hanley, H.J.M. (1996). 2J. Millat, J. H. Dymond and; C. A. Nieto (Eds.), Cambridge University Press. v 195 Chapter 4: Simulation Basis Environment LBC The LBC (Lohrenz-Bray-Clark) method is a predictive model which relates gas and liquid densities to a fourth degree polynomial in reduced density. In Multiflash, the fluid densities are derived from any chosen equation of state, rather than the correlations proposed by Lohrenz et al. This has the advantage that there is no discontinuity in the dense phase region when moving between liquid-like and gas-like regions. Multiflash also allows two variants of the LBC model. The first uses the original LBC method to estimate the critical volume of petroleum fractions and takes the critical volume of other components from the chosen data source. The second variant fits the critical volume of each component to reproduce the liquid viscosity at the boiling point. The method is mainly applicable to the types of components found in oil and gas processing but we recommend using the SuperTRAPP method in these cases. Pedersen The Pedersen method is a predictive corresponding states model originally developed for oil and gas systems. It is based on accurate correlations for the viscosity and density of the reference substance which is methane. The model is applicable to both gas and liquid phases. The Infochem implementation of the Pedersen model includes modifications to ensure that the viscosity of liquid water, methanol, ethanol, MEG, DEG, and TEG, and the aqueous solutions of these components or salt are predicted reasonably well. We recommend this method for oil and gas applications. Refer to Properties of Oils and Natural Gases1 . Thermal Conductivity SuperTRAPP The SuperTRAPP thermal conductivity method is an extended corresponding states model that uses propane as a reference fluid. It is applicable to both gas and liquid phases. The model can be used for petroleum fluids and well-defined components. The thermal conductivity is defined as the sum of internal and translational contributions. The latter is divided into three contributions: dilute gas, residual, and critical enhancement. The Multiflash model does not include a critical enhancement term. For pure substances, this can result in under-prediction of the thermal conductivity near the critical region. However, for a mixture, the critical enhancement is usually very small and negligible. The performance of the Super TRAPP method is generally better than the CLS method. 1Pedersen, Fredenslund and Thomassen, Gulf Publishing Co., (1989). 196 v Fluid Packages CLS The CLS (Chung-Lee-Starling) method is a predictive method for both gas and liquid mixture thermal conductivities. It requires the critical properties, Tci, Vci and wci for non-polar components. For polar and associating fluids, the dipole moment and an association parameter are also required. Association parameters for water, acetic acid, and the lower alcohols are provided. The fluid density is required as part of the calculation and this quantity may be obtained from any of the thermodynamic models in Multiflash. This method can be used for oil and gas processing and for polar mixtures. Surface Tension LGS The LGST (Linear Gradient Surface Tension) method is based on the Linear Gradient Theory model. LGST uses the properties of the phases in equilibrium to determine the interfacial tension. The key property is the density gradient that exists across the interface. With this model, it is possible to estimate the interfacial tension between Liquid/Gas and Liquid/Liquid phases. It can be used in combination with the any EOS-based fluid model except: LKP, CSMA, and the asphaltene model. Refer to Linear Gradient Theory Model for Calculating Interfacial Tensions of Mixtures1 . MCS The MCS (Macleod-Sugden) method predicts the surface tension (liquid-vapour) of a mixture based on the pure component parachors stored in a databank. It is mainly applicable to the types of components found in oil and gas processing. In this implementation, the vapour phase is described by the ideal gas equation. Refer to Properties of Oils and Natural Gases2 . MCSA The MCSA (Macleod-Sugden 2-phase variant) method predicts the surface tension (liquid-vapour) of a mixture based on the pure component parachors stored in a databank. It is mainly applicable to the types of component found in oil and gas processing. In this implementation, the gas phase is described by the selected model for the gas phase (instead of the ideal gas equation), and therefore, is more accurate than the 1-phase variant. Refer to Properties of Oils and Natural Gases3 . 1Zuo, Y. X. and Stenby, E. H., Journal of Colloid & Interface Science, 182 p12, Elsevier (1996). 2Pedersen, Fredenslund and Thomassen, Gulf Publishing Co., (1989). 3Pedersen, Fredenslund and Thomassen, Gulf Publishing Co., (1989). v 197 Chapter 4: Simulation Basis Environment GCEOS The Generalized Cubic Equation of State (GCEOS) is an alternative to the standard EOS property packages. It allows you to define and customize the cubic equation to your own specifications. The Parameters tab for the GCEOS consists of these groups: GCEOS Pure Component Parameters This group allows you to define α by specifying the values of κ -κ . Choose one of these options: 0 5 kappa0 To specify the value of κ , select the kappa0 option. The matrix contains four parameters of the 0 above equation, A, B, C and D for each component selected in the Fluid Package. 198 v Fluid Packages kappa1-5 To specify the remaining kappa parameters (i.e., κ -κ ), select the kappa1-5 option. Specify 1 5 the κ values for each component in the Fluid Package in the matrix. Volume Translation To specify the value of the pure component correction volume, c , select the Vol. Translation i option. v 199 Chapter 4: Simulation Basis Environment The GCEOS allows for volume translation correction to provide a better calculation of liquid volume by the cubic equations of state. The correction is a translation along the volume axis, which results in a better calculation of liquid volume without affecting the VLE calculations. Mathematically this volume shift is represented as: ν~ = v − ∑ Xi Ci i =1 n b° = b − ∑ Xi Ci i =1 where: ν~ = translated volume b° = the translated cubic equation of state parameter Ci = the pure component translated volume Xi = the mole fraction of component i in the liquid phase The resulting equation of state appears as shown in the EOS Enthalpy Calculation (GCEOS) ° calculations with b and v replaced with the translated values ( b and ν~ , respectively). The matrix contains the volume correction constants for each component currently selected. The matrix initially should be empty. Enter your own values into this matrix or click Estimate and have Petro-SIM estimate values for you. c is estimated by matching liquid volume at normal boiling point temperature with that of the i liquid volume obtained from an independent method (COSTALD). 200 v Fluid Packages GCEOS Parameters The GCEOS Parameters group allows you to specify the u and w parameters found in the EOS Enthalpy Calculation (GCEOS) equations. Petro-SIM only estimates the correction volume constant for those components whose cells have no value (i.e., they contain 0.000). If you specify one value in the matrix and click Estimate , you are only estimating those empty cells. To estimate a cell containing a previously entered value, select the cell, delete the current value and click the Estimate button. The u and w values for some common equations of state are: u EOS w van der Waals 0 0 Redlich-Kwong 1 0 Peng-Robinson 2 -1 The Equation Status bar tells you the status of the equation definition. There are two possible messages : Message Description EOS Not Ready Poor values were chosen for u and w. EOS Ready The values selected for u and w are suitable. Initialize EOS The Initialize EOS drop-down list allows you to initialize the GCEOS Parameters tab with the default values associated with the selected Equation of State. The four options available are: l l l l van der Waals Equation SRK Equation PR Equation PRSV Equation Refer to EOS Enthalpy Calculation (GCEOS) for more information. Kabadi Danner The Kabadi Danner property package uses Group Parameters that are automatically calculated by Petro-SIM. The values are generated from Twu’s method. v 201 Chapter 4: Simulation Basis Environment Peng-Robinson Stryjek Vera (PRSV) PRSV uses an empirical factor, Kappa, for fitting pure component vapour pressures. Zudkevitch Joffee The Zudkevitch Joffee property package uses b zero Parameters. Petro-SIM sets the b zero parameter of the ZJ equation to zero. 202 v Fluid Packages Chien Null The Chien Null property package provides a consistent framework for applying different activity models on a binary-by-binary basis. On the Parameters tab, you can specify the Activity Model to be used for each component pair, as well as two additional pure component parameters required by the model. The two groups present on the Parameters tab for the Chien Null property package are: Chien Null Component Parameters Values for the Solubility and Molar Volume are displayed for each library component and estimated for hypotheticals. The Molar Volume parameter is used by the Regular Solution portion of the Chien Null equation. The Regular Solution is an Activity Model choice for Binary pair computations. Refer to Binary Coefficients for further details. Chien Null Binary Component Parameters All components in the case, including hypotheticals, are listed in the matrix. You can view the details for the liquid and vapour phase calculations by selecting the appropriate option: l l Liq Activity Models Virial Coefficients By selecting the Liq Activity Models option, you can specify the Activity Model that Petro-SIM uses for calculating each binary. The matrix displays the default property package method selected by Petro-SIM for each binary pair. The choices are accessed by highlighting the drop- v 203 Chapter 4: Simulation Basis Environment down list in each cell. If Henry’s Law is applicable to a component pair, Petro-SIM selects this as the default property method. When Henry's Law is selected by Petro-SIM, you cannot modify the model for the binary pair. In the previous view, NRTL was selected as the default property package for all binary pairs. You can use the default selections, or you can set the property package for each binary pair. Remember the selected method appears in both cells representing the binary. Petro-SIM may filter the list of options according to the components involved in the binary pair. The property packages available in the drop-down list include: l l l l l l l None Required Henry van Laar Margules NRTL Scatchard Reg Soln General By selecting the Virial Coefficients option, you can view and edit the virial coefficients for each binary. Values are only shown in this table when the Virial Vapour model is selected on the Set Up tab. You can use the default values suggested by Petro-SIM or edit these values. Virial coefficients for the pure species are shown along the diagonal of the matrix table, while cross coefficients, which are mixture properties between components, are those not along the diagonal. Wilson The Molar Volume for each library component is displayed, as well as those values estimated for hypotheticals. 204 v Fluid Packages Chao Seader and Grayson Streed The Chao Seader and Grayson Streed property packages also use a Molar Volume term. Values for Solubility, Molar Volume and Acentricity are displayed for library components. The parameters are estimated for hypotheticals. Antoine Petro-SIM uses a six-term Antoine expression, with a fixed F term. For library components, the minimum and maximum temperature and the coefficients (A through F) are displayed for each component. The values for Hypothetical components are estimated. v 205 Chapter 4: Simulation Basis Environment Binary Coefficients The Fluid Packages Binary Coefficients tab contains a matrix table that lists the interaction parameters for each component pair. Depending on the property package selected, different estimation methods may be available and a different view may be shown. You have the option of overwriting any library value. The cells with unknown interaction parameters contain dashes (---). When you exit the Simulation Basis Manager, unknown interaction parameters are set to zero. For all matrices on the Binary Coeffs tab, the horizontal components across the top of the matrix table represent the i component and the vertical components represent the j component. For more information, refer to these interaction parameters: l l l 206 v Generalized Cubic Equation of State Equation of State Activity Model Fluid Packages GCEOS Interaction Parameters When GCEOS is the selected property package on the Set Up tab, the Binary Coeffs tab appears: The GCEOS property package allows you to select mixing methods used to calculate the equation of state parameter, a . Petro-SIM assumes the following general mixing rule: ij aij = ai a j MRij where MR = the mixing rule parameter. ij There are seven methods to choose for MR ij ( ) MRij T = 1 − Aij + Bij T + Cij T 2 MRij (T ) = 1 − Aij + Bij T + Cij / T ( ) ( ) ( ) MRij T = 1 − xi 1 − Aij + Bij T + Cij T 2 − xj 1 − Aij + Bij T + Cij T 2 MRij (T ) = 1 − xi (1 − Aij + Bij T + Cij / T ) − xj (1 − Aij + Bij T + Cij / T ) MRij (T ) = 1 − (k ij * kji ) xi k ij + xj k ji where v 207 Chapter 4: Simulation Basis Environment kij = Aij + Bij T + Cij T 2 MRij (T ) = 1 − (k ij * kji ) xi k ij + xj k ji where kij = Aij + Bij T + C ij T For the seventh method, refer to the Wong Sandler Mixing Rule. Each mixing rule allows for the specification of three parameters: A , B and C , except for the ij ij ij Wong Sandler mixing rule that has the A and B parameter and also requires you to provide NRTL ij ij binary coefficients. The parameters are available through the three options on the upper left corner: Aij, Bij and Cij/NRTL. Select a parameter’s option to view the associated parameter matrix table. When selecting the Cij/NRTL option, you are specifying the Cij parameter unless you are using the Wong Sandler mixing rule. In this case you are specifying NRTL binary coefficients used to calculate the Helmholtz energy. Wong Sandler Mixing Rule The Wong Sandler11 mixing rule is a density independent mixing rule in which the equation of state parameters a and b of any cubic equation of state are determined by simultaneously solving mix mix the: l l Excess Helmholtz energy at infinite pressure. Exact quadratic composition dependence of the second virial coefficient. To demonstrate this model, consider the relationship between the second virial coefficient B(T) and the equation of state parameters a and b: a B (T ) = b − RT Consider the quadratic composition dependence of the second virial coefficient as: 1Wong, D. S. H., Sandler, S. I., A Theoretically Correct Mixing Rule for Cubic Equations of State, A.I.Ch.E. Journal, 38, No. 5, p.671 (1992) 208 v Fluid Packages Bm (T ) = ΣΣxi xj Bij (T ) i j Substitute B with the relationship in the equation above: a a b mix − mix = ΣΣxi xj b − RT RT ij i j ( ) To satisfy the requirements of the above equation, the relationship for a ( ΣΣxi xj b − bmix = i j 1− a RT ij mix and b mix are: ) F (x ) RT with: a mix = b mixF (x ) where F(x) = an arbitrary function The cross second virial coefficient of the equation can be related to those of pure components by the following relationship: a b− = RT ij ( ) ai RT aj RT (b − ) + (b − ) 1 − A − B T i j 2 ( ij ij ) The Helmholtz free energy departure function is the difference between the molar Helmholtz free energy of pure species i and the ideal gas at constant P and T.  v   RT  i    P RT  IG Ai (T , P ) − Ai (T , P ) =  ∫ Pdv  −  ∫ dv  v v=∞  v =∞      The expression for Ae is derived using lattice models and therefore assumes that there are no free sites on the lattice. This assumption can be approximated to the assumption that there is no free volume. Thus for the equation of state: lim vi = bi P →∞ lim vmix = b mix P →∞ b can be approximated by the following: mix v 209 Chapter 4: Simulation Basis Environment Σ Σ i bm ix = A ∞e x () 1+ therefore a am ix = b m ix RT mix Σ i j a RT ij ( ) xixj b − − Σ i ai biRT ( ) xi is: a bi xi i − A ∞e(x ) and F(x) is: F(x) = Σ i a bi e xi i − A ∞ (x) A ∞e (x ) , is calculated using the NRTL model. You are required to The Helmholtz free energy, supply the binary coefficient values on the parameters matrix when the Cij/NRTL option is selected. α term is equal to 0.3. EOS Interaction Parameters The Equation of State Interaction Parameters group is shown for the following property packages: l l l l l l l l 210 v Kabadi Danner Lee-Kesler Plöcker PR PRSV Soave Redlich Kwong, SRK Sour PR Sour SRK Zudkevitch Joffee Fluid Packages The numbers displayed in the table are initially calculated by Petro-SIM, but you can modify them. All known binary interaction parameters are displayed, with unknowns displayed as dashes (---). You have the option of overwriting any library value. For all Equation of State parameters (except PRSV) K = K , so when you change the value of ij ji one of these, both cells of the pair automatically update with the same value. In many cases, the library interaction parameters for PRSV do have K = K , but Petro-SIM does not force this if you ij j modify one parameter in a binary pair. If you are using PR or SRK (or one of the Sour options), two options are available. Select this Option To... Estimate HCHC/Set Non HCHC to 0.0 (default) Petro-SIM automatically generates hydrocarbon-hydrocarbon interaction parameters when values are unknown, setting all non-hydrocarbon pairs to 0. Set All to 0.0 Petro-SIM sets all interaction parameter values to 0.0. It disables the automatic calculation of any estimated interaction coefficients between hydrocarbons. All binary interaction parameters that are obtained from the pure component library remain. This option is useful when trying to match results from other commercial simulators that do not supply interaction parameters for higher molecular weight hydrocarbons. v 211 Chapter 4: Simulation Basis Environment Activity Model Interaction Parameters The Activity Model Interaction Parameters group is displayed on the Binary Coeffs tab when one of the following Activity Models is selected: l l l l l l l l Chien Null Extended NRTL General NRTL Margules NRTL UNIQUAC van Laar Wilson The interaction parameters for each binary pair are displayed. Unknown values show as dashes (--). You can overwrite any value or use one of the Coeff Estimation methods. To display a different coefficient matrix (i.e., B ) select the appropriate option: ij , l l Aij Bij Coeff Estimation When using Activity Models, Petro-SIM provides three interaction parameter Coeff Estimation methods. 212 v Fluid Packages UNIFAC estimations are by default performed at 25°C, unless you change this value on the Set Up tab. The fluid package stores one set of parameters. l l l UNIFAC VLE - if you plan to do mostly liquid-liquid modelling. UNIFAC LLE - if you plan to do mostly vapour-liquid modelling. Immiscible - The three buttons used for the UNIFAC estimations are replaced by: n Row in Clm Pair. Click to estimate the parameters such that the row component (j) is immiscible in the column component (i). n Clm in Row Pair. Click to estimate parameters such that the column components (j) are immiscible in the row components (i). n All in Row. Click to estimate parameters such that both components are mutually immiscible. If you need to model both VLE and LLE, then for optimal results you can use two different fluid packages and use the appropriate one in the appropriate sections of your model. Because the Wilson equation does not handle 3-phase systems, the Coeff Estimation group does not show the UNIFAC LLE or Immiscible options when this property package is used. Click... To... Individual Pair This button is only visible when UNIFAC VLE is selected. It calculates the parameters for the selected component pair, Aij and Aji. The existing values in the matrix are overwritten. Unknowns Only Estimate any missing values. If you delete the contents of cells or if Petro-SIM does not provide defaults values, you can use this option and have Petro-SIM calculate the activity parameters for all the unknown pairs. v 213 Chapter 4: Simulation Basis Environment Click... To... All Binaries Estimate ALL interaction parameters. Recalculates all the binaries in the matrix. If you had changed some of the original Petro-SIM values, you can use this to have Petro-SIM re-estimate the entire matrix. Reset Reset the binary parameters to their original library values. Parameters Generally you want to use library interaction parameters whenever they are available (click Reset Params to retrieve them if need be). Then manually enter values for any missing parameters if you have values for them from an external source. Sources such as DECHEMA and DIPPR often report the regressed parameters, though sometimes you have to perform a conversion (Carefully read exactly what they are reporting. Usually there is a description of the definition of the parameters with some information about variations used in different systems). If any values are still missing, click Unknowns Only to estimate the missing values. Stability Test The Fluid Packages Stability Test tab is where you can instruct Petro-SIM on how to perform phase stability calculations in the Flowsheet. If you encounter situations where a flash calculation fails or you are suspicious about results, you can use this option to approach the solution using a different route. The Stability Test can be thought of as introducing a droplet of nucleus into the fluid. The droplet then either grows into a distinctive phase or is dissolved in the fluid. For multi-phase fluids, there exist multiple false calculated solutions. A false solution exists when convergence occurs for a lower number of phases than exists in the fluid. For example, with a three-phase fluid, there is the correct three-phase solution, at least three false 2-phase solutions and multiple false single-phase solutions. A major problem in converging the flash calculation is arriving at the right solution without prior knowledge of the number of equilibrium phases. The strategy used in Petro-SIM is as follows: 1. Unless there is strong evidence for three phases, Petro-SIM first performs a 2-phase flash. 2. The resulting phases are then tested for their stability. 214 v Fluid Packages Stability Test Parameters Group Specify the maximum number of phases allowed (2 or 3) in the Maximum Phases Allowed field. If this value is set to 2, the stability test quits after 2-phase flashes. Occasionally, you may still get three phases, as the flash may attempt to start directly with the 3-phase flash. The Stability scheme used is that proposed by Michelson. In the Method group, select the method for performing the stability test calculations by selecting one of these options: Select... To do this... None No stability test is performed. Low Use a default set of Phases/Components to Initiate the Stability Test. This method includes the Deleted phases (if they exist), the Wilson's Equation initial guess and the Water component (if it exists) in the fluid. Medium In addition to the options used for the Low method, this method also includes the Average of Existing phase, the Ideal Gas phase and the heaviest and lightest components in the fluid. All All available Phases and Components are used to initiate the test. User Allows you to activate any combination of check boxes in the Phase(s) to Initiate Test and Comp(s) to Initiate Test groups. If you make changes when a default Method option (i.e., Low, Medium) is selected, the method is changed to User automatically. Old Flash No stability test is performed. Use the default flash 3 option with the stability parameter set to none. v 215 Chapter 4: Simulation Basis Environment Phases to Initiate Test There are four choices listed in the Phase(s) to Initiate Test group. These check boxes are activated according to the option selected in the Method group. If you change the status of any option, the option in the Method group is automatically set to User. Check... To... Deleted If a phase is removed during the 2-phase flash, a droplet of the deleted fluid is re-introduced. Average of Existing The existing equilibrium fluids are mixed in equal portions; a droplet of that fluid is introduced. Ideal Gas A small amount of ideal gas is introduced. Wilson's Equation A hypothetical fluid is created using the Wilson's K-value and is used to initiate the stability test. If any one of these initiating nuclei (initial guesses) forms a distinctive phase, the existing fluid is unstable and this nucleus provides the initial guess for the 3-phase flash. If none of these initial guesses shows additional phases, it can only be said that the fluid is likely to be stable. One limitation with the stability test is that it relies on the property package chosen rather than physical reality. At best, it is as accurate as the property package. For instance, the NRTL package could actually predict numerous equilibrium phases that do not exist. Turning on all initial guesses for NRTL may not be a good idea. Temperature Limits The temperature limits are not used in Petro-SIM. Components to Initiate Test When a droplet of nucleus is introduced into the fluid, the droplet either grows into a distinctive phase or is dissolved in the fluid. Another obvious choice for the droplet composition is one of the existing pure components. For example, if the fluid contains hexane, methanol and water, try introducing a droplet of hexane, a droplet of methanol or a droplet of water. The choices for the pure component droplets are listed in the Comp(s) to Initiate Test group. Rxns In the Basis Environment, all reactions are defined through the Rxns tab (that is, Reaction Manager). On the Rxns tab of the Fluid Package property view, you are limited to attaching/detaching reaction sets. 216 v Fluid Packages The objects for the Rxns tab within the Fluid Package property view are. This list... Displays... Current Reactions All currently loaded reactions set in this Fluid Package. Sets Associated Reactions All the reactions associated with the respective selected Reaction Set. There are two Associated Reactions list boxes. Available Reactions Sets All available Reactions Sets in the case. Click Add Set to attach selected Reaction Sets in the Available Reaction Set to the Fluid Package and display them in the Current Reactions Sets group. To remove selected Reaction Sets from the Fluid Package, click Remove. To access the Reaction Manager, click Simultaneous Basis Mgr. Tabular The Fluid Packages Tabular tab is where every property for all components in a case can be calculated. It is best used for matching a specific aspect of your process. v 217 Chapter 4: Simulation Basis Environment Refer to Using the Tabular Package to learn how to use this feature. A typical example would be in the calculation of viscosities for chemical systems, where the Tabular Package often provides better results than the Activity Models. The Heat of Mixing property can be applied in one of two manners. For Activity Models that do not have Heat of Mixing calculations built in, this allows you to supply data or have the coefficients estimated and have Heats of Mixing applied throughout the flowsheet. EOSs account for Heat of Mixing in their enthalpy calculations, and in certain instances predict the value incorrectly. You can use this route to apply a correction factor to the EOS. In cases where the EOS is predicting too high a value, implementing a negative Heat of Mixing can correct this. Packages can regress the experimental data for select thermophysical properties such that a fit is obtained for a chosen mathematical expression. The Tabular Package is used in conjunction with one of the Petro-SIM property methods. Your targeted properties are then calculated as replacements for whatever procedure the associated property method would have used. Tabular Package calculations are based on mathematical expressions that represent the pure component property as a function of temperature. The values of the property for each component at the process temperature are then combined, using the stream composition and mixing rule you specify. The Tabular Package provides access to a comprehensive regression package. This allows you to supply experimental data for your components and have Petro-SIM regress the data to a selected expression. A variety of expressions are available to represent the property data. There are 32 basic equation shapes, 32 Y-term shapes, 29 X-term shapes, as well as Y and X power 218 v Fluid Packages functions. The Tabular Package provides plotting capabilities to examine how well the selected expression predicts the property. You are not restricted to the use of a single expression for each property. Each component can be represented using the best expression. You may not need to supply experimental data to use the Tabular tab. If you have access to a mathematical representation for a component/property pair, you can select the correct equation shape and supply the coefficients directly. Also, Petro-SIM provides a database for nearly 1,000 library components so you can use this information directly within the Tabular Package without supplying any data. When experimental data is supplied, it is retained in the memory by Petro-SIM and stored in the case. Using the Tabular Package There are only two requirements for using the Tabular Package: l l Most properties require that all components in the case have their property value calculated by the Tabular Package. Enthalpy calculations require that the Tabular Package be used for both the liquid and vapour phase calculations. Similarly, you may use only one enthalpy type property for each phase. For example, liquid enthalpy and liquid heat capacity cannot both be selected. An extension to this occurs when the latent heat property is selected. When this property is activated, only one enthalpy type property or one heat capacity property may be selected. To use the Tabular Package, follow these steps below. 1. Enable the Options, Configuration and Notes pages by selecting the Enable Tabular Properties check box. v 219 Chapter 4: Simulation Basis Environment 2. Select the Basis for Tabular Enthalpy by clicking the appropriate option: l H = 0 at 0 K l H = Heat of Formation at 25C 3. Expand the Options tree to view these pages: l All Properties l Physical l Thermodynamic 4. Select the check boxes in the Use Petro-SIM or Use PPDS columns for the desired target properties. 220 v Fluid Packages 5. When a target property is selected on one of the three options pages, you may select the Mixing Basis by using the drop-down list. The Parameter value may also be changed on this page. 6. As properties are added, the Information tree expands to add a page for each selected property. Expand the Information tree to view the property pages. 7. The Tabular tab of the fluid package property view contains two pages and three trees of information, which are displayed at different times depending on the options selected. These pages are: l l l l l Configuration Options - appears only after Enable Tabular Properties is checked. Information - appears only after properties are targerted in the Options tree. Heat of Mixing - appears only when Heat of Mixing is activated on the All Properties or Thermodynamics pages in the Options tree. Notes - use to provide additional comments or notes. 8. To view the existing library information, first select the property page you want from the Information tree. Refer to Information and Heat of Mixing pages for more details about view the properties on these pages. 9. To view the existing library information on a component plot, click Cmp Plots. 10. To view the PropCurve view for a selected component, highlight a value in the column of the desired component and click Cmp Prop Detail. Configuration Page The Tabular tab Configuration page contatins two groups of data described below. v 221 Chapter 4: Simulation Basis Environment Global Tabular Calculation Options Check... To... Enable Calc. on Active Property Enables all selected Active Properties to be calculated using the Tabular Package. If this check box is not selected, all properties are calculated by the Property Package. Enable Tabular Properties Toggle the Tabular Properties on or off. Enables the Options, Information, and Notes pages. If this option is not checked, no other pages are available and the tab is purged of any tabular property data it might have previously contained. Basis for Tab. Enthalpy (ideal gas) This group becomes active after the Enable Tabular Properties check box is selected. It allows you to select between the enthalpy basis for tabular calculations: l l H = 0 K, ideal vapour H = Heat of formation at 25°C, ideal vapour Options Pages You can target a property through the three pages available in the Options tree. Expand the Options group to display these pages: 222 v Fluid Packages l l l All Properties Physical Thermodynamics Each page consists of a five column matrix table that displays data in these columns: Property Type The All Properties page consists of seventeen properties that are subdivided into two groups and displayed on either the Physical or Thermodynamics page. These properties and their subgroups are: l l l l l l l l l l l l l K-value (V/L1)[Thermodynamic] K-value (V/L2)[Thermodynamic] K-value (L1/L2)[Thermodynamic] Enthalpy(L)[Thermodynamic] Enthalpy(V)[Thermodynamic] Latent Heat[Thermodynamic] Heat Capacity(L)[Thermodynamic] Heat Capacity(V)[Thermodynamic] Heat of Mixing[Thermodynamic] Viscosity (L)[Physical] Viscosity (V)[Physical] Thermal Cond (L))[Physical] Thermal Cond (V))[Physical] v 223 Chapter 4: Simulation Basis Environment l l l l Surface Tension[Physical] Density (L)[Physical] Entropy(L)[Thermodynamic] Entropy(V)[Thermodynamic] Comp. Basis The Composition Basis column allows you to select the Basis (mole, mass, or liq volume) on which the mixing rule is applied. When you select a property type, the Composition Basis becomes active for that property. The available options can be accessed from the drop-down list in the cell of each property selected. The default mixing rule that is applied when calculating the overall property is shown in the form: 1  f Propertymix =  xi Propertyif  i   Σ Mixing Parameter The Mixing Parameter column allows you to specify the coefficient (f) to use for the mixing rule calculations. The default value is 1.00. The value that Petro-SIM uses as the default is dependent on the property selected. For instance, if you select Liquid Viscosity as the property type, PetroSIM uses 0.33 as the default for the Mixing Parameter. Information Pages After properties are activated on one of the three pages in the Options tree, the property page for that property appears in the Information tree. Expand the Information group to display the pages for the selected properties. The Heat of Mixing property does not create a page in the Information tree, but instead creates a Heat of Mixing tree consisting of pages for Heat of Mixing components. 224 v Fluid Packages A component may be targeted by clicking in any cell in the component’s column. For example, if Propane was the component of interest, click in any cell in the third column. Once the component is targeted, click Cmp Prop Detail to open the PropCurve view that contains most of the information displayed on the Information pages. Parameters for the componnet can be changed on either the property page or the PropCurve view. Click Cmp Plot to create the plot showing Temperature vs. the selected Property Type in the Component Plot view. Heat of Mixing Pages When the Heat of Mixing property is activated on either the All Properties or the Thermodynamic page in the Options tree, a new Heat of Mixing tree gets added to the Tabular Package. v 225 Chapter 4: Simulation Basis Environment The UNIFAC Estimation Options group contains these options: Object Description Temperature Displays the reference temperature at which the UNIFAC parameters are calculated. UNIFAC VLE Click to have Petro-SIM use the UNIFAC VLE estimation method to calculate the binary coefficients. This overwrites any existing coefficients. UNIFAC LLE Click to have Petro-SIM use the UNIFAC LLE estimation methods to calculate the binary coefficients. This overwrites any existing coefficients. Expand the Heat of Mixing tree to view the composition pages, which are very similar to the Information pages. Click View Details to view a modified PropCurve view. PropCurve View When you specify the flowsheet properties for which you want to use the Tabular Package, you can change the data Petro-SIM uses in calculating the properties in the PropCurve view. PetroSIM contains a data file with regressed coefficients and the associated equation shapes for most components. If Heat of Mixing is used, you can access the PropCurve by selecting the component and then clicking the View Details button. The PropCurve view does not include the Coeffs tab for Heat of Mixing properties. 226 v Fluid Packages Modify or view the property's data in these PropCurve tabs: l l l l l Variables Coeff Table Plot Notes Variables The Supplying Tabular Data Variables tab is the first tab of the PropCurve property view. It contains these groups: v 227 Chapter 4: Simulation Basis Environment X-Variable This group contains information relating to the X-Variable. Cells Description X Since all properties are measured versus Temperature, this cell always shows Temperature when using the Tabular Package. Unit Displays the units for the temperature values. You cannot change the units here. The Petro-SIM internal units for Temperature, K, are always used. Shape This is the shape of the X variable. The choices for the X Shape can be accessed using the drop-down list in the cell. There are 29 available shapes. Use the scroll bar to move through the list. In this case, the shape selected is Xvar:x. This means that the X variables in the equation are equal to X, which represents temperature. If LogX:log10(x) is selected as the X Shape, then the X variables in the equation are replaced by log10(x). Shape Norm This is a numerical value used in some of the X Shapes. In the drop-down list for X Shape, notice that the second choice is Xreduced:x/ norm. The x/norm term, where norm = 190.70, replaces the X variable in the equation. You can change the numerical value for Norm in the cell. Exponent Allows you to apply a power term to the X term, for example, X0.5. Eqn Minimum Defines the minimum boundary for the X variable. When a flowsheet calculation for the property is outside the range, Petro-SIM uses an internal method for extrapolation of the curve. This method is dependent on the Property being used. See Equation Form. Eqn Maximum Defines the maximum boundary for the X variable. When a flowsheet calculation for the property is outside the range, Petro-SIM uses an internal method for extrapolation of the curve. This method is dependent on the Property being used. See Equation Form. Y-Variable This group contains all information relating to the Y-Variable. 228 v Cells Description Y This is the property chosen for Tabular calculations. Unit Displays the units for the Y variable. You cannot change the units here, it must be done through the Basis Manager (Preferences option). Fluid Packages Cells Description Shape This is the shape of the Y variable. The choices for the Y Shape are available using the drop-down list within the cell. There are 32 shapes selected. Use the scroll bar to move through the list. In this case, the shape chosen is Yvar:y. This means that the Y variables in the equation are equal to Y, which represents enthalpy. If LogY:log10(y) is chosen as the Y Shape, then the Y variables in the equation are replaced by log10(y). Shape Norm This is a numerical value used in some of the Y Shapes. In the drop-down list for Y Shape, notice that the second choice is Yreduced:y/ norm. The Y variable in the equation is replaced by the y/norm value. This numerical value can be changed within the cell. Exponent Allows you to apply a power term to the Y term, for example, Y0.5. Q-Variable This group contains all information relating to the Q Variable. This variable is used in some of the X and Y Variable equations. Cell Description Q Represents the Q variable that is always Pressure. Unit Displays the units for the Q Variable, which are always the default internal units of pressure, kPa. Default This is the default numerical value given to the Q Variable that can be modified within the cell. Coefficients This group is only visible on the Heat of Mixing page when it is an active property. v 229 Chapter 4: Simulation Basis Environment The Coefficients group contains the coefficient values either obtained from the Petro-SIM database, or regressed from data supplied in the Table tab. Equation Form Petro-SIM selects a default Equation Shape, depending on the property you have selected. You have the option of using this equation or selecting a different equation from the drop-down list associated with this cell. This list contains 33 available equations to choose from. When Petro-SIM cannot regress the data to produce equation coefficients for the selected equation shape, the message Non-Regressable appears on the right of the drop-down list. You can still use the equation shape, but you have to manually enter the coefficients. 230 v Fluid Packages Some equation shapes only let you supply coefficients directly. You are informed if the equation shape cannot have tabular data regressed to it. Coeff The Supplying Tabular Data Coeff tab displays the current coefficients for the specified equation. This view also contains the Equation Form group, so you can change the equation from this tab. The X, Y and Q variables and their units are displayed for reference only. They cannot be modified. The Coefficients group contains the coefficient values either obtained from the Petro-SIM database or regressed from data supplied in the Table tab. The check boxes supplied next to each coefficient value let you fix the default or input values. Petro-SIM will not to regress these coefficients. Table The Supplying Tabular Data Table tab allows to enter your tabular data before or after selecting the Equation Shape. v 231 Chapter 4: Simulation Basis Environment If the component is from the Petro-SIM library, 20 points are generated between the current Min and Max temperatures. If you need to supply data, click Clear Data. You can also add your data to the Petro-SIM default data and have it included in the regression. Supplying Data If you are going to supply data, select the unit cell under the X and Y variable columns and press any key to open the drop-down list. From the list you can change to the appropriate units for your data. The procedure for supplying data is as follows: 1. Select the appropriate units for your data. 2. Clear the existing data with the Clear Data button, or move to the location that you want to overwrite. 3. Supply your data. 4. Supply Net Weight Factors, if desired. To delete a particular data point, highlight the data point and click Delete. Coefficients calculated using the deleted data are still present on the Coeff tab until you click Regress. Q-Column This column contains the Pressure variable. The presence of this extra variable helps provide better regression for the data. As with the X and Y variables, the units for pressure can be changed to any units available in the drop-down list. 232 v Fluid Packages Wt Factor You can apply weighting to individual data points. When the regression is performed, the points with higher weighting factors are treated preferentially ensuring the best fit through that region. Regressing the Data After you provide the data, you need to update the equation coefficients. Click Regress to have Petro-SIM regress your data, generating the coefficients based on the current shapes. If you then change any of the equation shapes, the data you supplied is regressed again. You can reenter the regression package and select a new shape to have your data regressed. Data Retention When experimental data is supplied, it is retained by Petro-SIM in memory and stored in the case. Later, you can come back into the Tabular Package and modify the data for the property. Petro-SIM regresses the data once again. Plot The PropCurve Plot tab allows you to examine how the current equations and coefficients represent the property on a plot. Only the selected component (in this case Hydrogen) is displayed. The plot contains two curves, one plotted with the regressed equation and the other with the Table values. If the tabular values supplied on the Table tab are in different units, they are still plotted using the Petro-SIM internal units. This provides a means for gauging the accuracy of the regression. In this example, the two curves overlap each other, such that it appears to only show one curve. v 233 Chapter 4: Simulation Basis Environment Besides displaying the component curve, this view also displays the number of points used in determining the tabular equation (in this case 20). As well, the x-Axis group displays the Min and Max x-values on the curve.You can change the Min and Max x-axis values and have Petro-SIM extend the curve appropriately. Right-click the plot area to open the Graph Control view for more options. Component Plots View The Component Plot view displays the curves for components selected in the Fluid Package when you click Cmp Plot on the component property pages. Petro-SIM uses the current expressions to plot the graphs, either from the Petro-SIM library or your supplied regressed data. Petro-SIM can only plot four curves at a time. The Curve Selection group lists the components that are plotted on the graph. The default is to plot the first four components in the component list. To replace the default components in the Curve Selection group with other components, select the component you want to add from the drop-down list. The new component replaces the previously selected component and Petro-SIM redraws the graph, displaying the data of the new component. The Variables group shows the property used for the X and Y axis (Enthalpy vs. Temperature in this case). Right-click the plot area to open the Graph Control view for more options. Close the plot view to return to the Information page. Phase Order The Phase Order tab is intended for Dynamics mode but affects steady state as well. 234 v Components Petro-SIM dynamics always uses three phases for streams and fluids in the stream property view. For each unit operation, dynamics also assumes that the same material is in the same phase slot for all of the connected streams. The order of the first phase is always vapour and the second phase is liquid . The third phase may be aqueous or it can be a second liquid phase. By default, Petro-SIM sorts these phases based on their Type (liquid or aqueous) and Phase Density. Subtle changes to the stream properties may change the order. Stream properties displayed as a liquid phase in one instance may be displayed as an aqueous phase in another. For example, inside a tray section the composition of a phase may change so that instead of being aqueous, it is a liquid phase. The phase moves to a different slot in the fluid. This can cause disturbances in dynamics mode. Components Components, which are grouped into one or more component lists or collections of library pure components or hypothetical components, must be defined for every Petro-SIM case. Components can be attached to one or more fluid packages in your case. From the Simulation Basis Manager view, select the Components tab to view and manage the Component Lists in your case v 235 Chapter 4: Simulation Basis Environment The Components Manager always contains a Master Component List that cannot be deleted. The Master Component List contains every component available from all component lists. If you add components to any other Component List, they are automatically added to the Master Component List. Also, if you delete a component from the master, it is deleted from all other Component Lists that are using it. The Components tab of the Simulation Basis Manager view contains six buttons that let you organize all component lists in the current case. 236 v Click this... To... View View the selected the Component List . You can add, modify, or remove individual components from the current list. Add Add a new Component List to the case and open the Component List view. New components can be added to the component list by highlighting the component list name and clicking the View button. Delete Delete a Component List from the case. No warning message is provided before deleting a list and a deleted Component List cannot be recovered. Copy Make a copy of the selected Component List. The copied version is identical to the original, except for the name. This option is useful for modifying Component Lists while keeping the original list intact. Import Import a predefined Component List. When the Import button is selected, the location dialog window for the component list file appears. Component Lists have a file extension of (*.cml). Components Click this... To... Export Export the selected Component Lists (*.cml) to disk. The exported list file can be retrieved in another case by using the Import button. Refresh Reload component data from the database. For example, if you have a case from a previous version, the data is updated from the older version to the latest version. Check the Show System Components Lists option to show the system component lists such as the Master Component List and Synthesis Component List. Components are associated with Fluid Packages through Component Lists. A Component List must be selected for each Fluid Package created. You cannot associate the Master Component List to a fluid package. Instead, add a new component list and associate it to the fluid package. For more details about using Component Lists with fluid packages, refer to Fluid Package. Component List View Use the Component List view to modify or view an existing component list or add a new component list to the case. To open the Component List view, click View or Add on the Components tab of the Simulation Basis Manager. Use the Component List view to add components to a component list. Access is provided to all Library components within Petro-SIM, including traditional Components, defined Hypotheticals and Other existing lists. This view consists of the following tabs: v 237 Chapter 4: Simulation Basis Environment Selected The Selected tab lets you add components and view their properties. The Components page view varies according to the selection in the Add Component group. The Selected tab view has three main groups: Add Component The Add Component section lets you filter components by type. Select components from the component tree displayed in the Components Available in Component Library group. A different view is displayed depending on whether you are adding Traditional, Hypothetical, or Other components. Selected Components The Selected Components group shows the list of components that were added. The functions are used to manipulate the list of selected components include the following: Object Description Selected Component List Contains all the current components for a particular component list. Add Pure Adds the highlighted component(s) from the Components Available group to the Selected Component List. Substitute Exchanges the highlighted selected components with the highlighted available component. Remove Deletes the highlighted component from the Selected Component List. Sort List Opens the Move Components view, where you can change the order of the selected component list. View Component Opens the selected component’s identification property view. When substituting components, Petro-SIM replaces the component throughout the case (i.e., all specifications for the old component are transferred to the new component). The substitution function does not automatically handle components that are part of a Reaction. Components Available in the Component Library The Add Component tree lets you filer components by type. Select the components you want from the component tree displayed in the Components Available in Components Library group. A different view is displayed depending on whether you are adding Traditional, Hypothetical, or Other components. 238 v Components Object Description Match As you type in this cell, Petro-SIM filters the component list to locate the component that best matches your current input. This depends on the radio button selected. View Filter button This button opens the Filters floating view that contains a range of property packages and component filtering options to help with component selection process. Sim Name These three option determine the context of your input in the Match cell. Full Name Synonym Formula Show Synonyms When this check box is activated, Petro-SIM includes known synonyms for each component in the list. Cluster This check box is available only when the Show Synonyms check box is checked. By selecting the Cluster check box, all synonyms are indented and listed below the component name. Otherwise, the synonyms are listed alphabetically throughout the list. Component by Type The Component by Type tab displays all components selected for the component list by its particular type as shown. v 239 Chapter 4: Simulation Basis Environment Selecting Library Components Adding components from the component library to the Selected Components list can be done using the following steps: 1. Filter the library list by: l Traditional components l Hypothetical components l Other 2. Select the desired components. 3. Transfer the components to the Selected Components list. When components are highlighted in the Available List, click the Add Pure button to move them to the Selected Component List. Filtering for Traditional Components Use these available tools to filter the component library. This narrows the selection range and lets you transfer the selections to the Selected Components list. Filtering options for hypotheticals are different and available in Add Hypothetical Components. There are four options available for filtering that can be used independently or in combination: Filtering Tool Description Property Package Filter Filters the list according to your selection of property package and/or component families. and Family Type Filters Show Synonyms Component synonyms appear alphabetically throughout the list when this check box is activated. Cluster The Cluster check box is available only when the Show Synonyms check box is selected and Match input field is empty. By selecting the Cluster check box, all synonyms are indented and listed below the component name. Match This input cell lets you type-match the component simulation name, full name, synonym or formula. By using the Match field, you can access any component within the Petro-SIM library that is accessible under the currently selected Property Package. You can make the Match field active by selecting it or by pressing ALT+M. The Match field accepts any character and is used to locate the component in the current list that best matches the characters. The first character of the filtered component names must agree with 240 v Components first character of the listed component name. Subsequent characters in the Match field must appear somewhere in each listed component name. Other than the first character, any number of unmatched characters can appear within the names of the listed components. When trying to match a component, Petro-SIM searches the component column in the list for which option is selected: Option Description Sim Name This option matches the text entered into the Match input to the name used within the simulation. Full Name/ Synonym This option may match the components full name or a synonym of the SimName. It is typically a longer name. Formula Use this option when you are not sure of the library name, but know the formula of the component. For example, if you want to add Water, type H2 in the Match cell. Petro-SIM filters the list of available Library Components to only those that match your current input string. The first component in the list, H2, is an exact match of your current input and therefore, is highlighted. Notice that H2O is available in the list even though you have entered only H2. To reduce the list of available library component options, type in the character O after the H2 in the Match field. v 241 Chapter 4: Simulation Basis Environment Click View Filters to open the Filters view. Select a property package from the Property Package Filter group to filter components based on their compatibility with the selected property package. l l Check Recommended Only to display only components that are recommended with the chosen property package. De-select Recommended Only all components display in the component library list. An x is shown beside each component that Petro-SIM does not recommend for the selected property package. You may still select these components. Use the Family Type Filter group to filter the list of available components to only those belonging to a specific family. The Use Filter check box, when selected, toggles the Family Type Filter options On and Off. By default, all check boxes in the group are deactivated. You can identify which families should be included in the list of available components by selecting the desired check boxes. The All button activates all check boxes and the Invert button toggles the status of each check box individually. For example, if you select all of the check boxes and then want to quickly deselect them, click the Invert button. If you only had the Hydrocarbons and the Solids options selected and you clicked the Invert button, these two options are deactivated and the remaining options are activated. The Property Package Filter is only a component selection filtering tool and does not associate a Fluid Package with the component list. Transfer the Components After the Library Component list is filtered and the components you want are highlighted, transfer the selections to the Selected Components list using one of the following methods: l l l Click the Add Pure button Press ENTER Double-click the highlighted item. This option only works when you select a single component. The methods are the same whether you are adding traditional components, hypotheticals, or other components. 242 v Components Add Hypothetical Components Hypotheticals can be added to a component list through the Components List view. In the Add Components group of the selected tab, select the Hypothetical page from the tree configuration list. The Components List view lists the Hypothetical components in the Component List. Some features from the Selected tab are common to both the selection of Hypotheticals and Library components. Items specific to Hypotheticals are listed and described in the table below. Object Description Add Group Adds all the Hypothetical components in the Hypo Group list selection to the Current Component List. Add Hypo Adds the currently selected Hypothetical in the Hypo Component list to the Current Component List. Hypo Group Displays all the Hypo Groups available to the current component list. Hypo Components Displays all the Hypothetical components contained in the currently selected Hypo Group. Hypo Manager Opens the Hypotheticals tab of the Simulation Basis Manager, from which you can create, view, or edit Hypotheticals. Quick Create a Hypo Comp Creates a Hypothetical component, adding it to the currently selected Hypo Group, and opens its property view. Quick Create a Solid Hypo component Creates a solid Hypothetical component, adding it to the currently selected Hypo Group, and opens its property view. v 243 Chapter 4: Simulation Basis Environment To access all features for Hypotheticals and Hypothetical groups, go to the Hypotheticals tab of the Simulation Basis Manager. Add Other Components Components can be added from other component lists by using the Other List option. In the Add Components group, select Other. The Components tab is displays the alternate component lists. The Existing Components group displays a list of all available component lists loaded into the current case. Highlighting a component list name displays its associated group of components in the Selected Component List. Highlight the component name in the list and click the Add button to transfer a component from an existing component list. The highlighted component is added to the Selected Components list Manage the Selected Components List After adding the components to the Selected Components list, you can substitute, remove, sort and view components. These methods apply to traditional library components, hypotheticals and other components. To demonstrate the manipulation functions, the Selected Components group shown below is used for reference purposes. 244 v Components Remove Selected Components You can remove any component(s) from the Selected Components list by the following steps: 1. Highlight the component(s) you want to delete. 2. Click the Remove button, or press the Delete key. For Library components, Petro-SIM removes the component(s) from the Selected Components list and places them back in the Components Available in the Component Library list. Since Hypothetical components are shared among Fluid Packages, there is no actual transfer between the lists (i.e., The Hypo always appears in the Available group, even when it is listed in the selected Components list). Refer to Hypotheticals for more information about Hypothetical components. Substitute Components When substituting components, Petro-SIM replaces the component throughout the case (i.e., all specifications for the old component are transferred to the new component). The substitution function does not automatically handle components that are part of a Reaction. You can only substitute one component at a time. Even though Petro-SIM lets you highlight multiple components, the substitution only involves the first highlighted component. 1. In the selected Component List, highlight the component you want to remove. 2. In the Available Component list, highlight the component to be substituted. 3. Click the Substitute button. The removed component is returned to the Available Component list and the substituted component is placed in the Selected Component List. Sort a Component List You can use the Sort List button to rearrange the order of the selected components. v 245 Chapter 4: Simulation Basis Environment Using the view shown above, the procedure is: 1. Click the Sort List button and the Move Components view appears. You can highlight and move multiple components. 2. From the Component(s) to Move group, select the component you want to move. In this example, Ethane is selected. 3. In the Insert Before column select Propane. 4. Click the Move button to complete the move. Ethane is inserted before Propane in the component list. 5. When you have completed the sorting, click the Close button to return to the Components tab. You can highlight and move multiple components. View Components Once a component is added to the Selected Components list, the View Component button becomes active. The View Component button lets you view and edit properties of the specified component in the Pure Component property view. The property views are different and specific to the type of component selected. You can also examine the property view for any component in the Selected Component List by double-clicking on the component. 246 v Components Pure library components and hypothetical components share the first type of property view but you can only modify the properties in the hypotheticals view. The Edit Properties feature lets you edit pure component and solid properties. Refer also to Hypotheticals for more information. The second property view is shared by pure component solids and hypothetical solids. You cannot directly modify the pure component solid properties but you can modify Hypotheticals. Each view consists of five tabs. Throughout the tabs, the information is displayed in red, blue and black. Values displayed in red are estimated by Petro-SIM. Values displayed in blue are entered by you. Black values represent calculated values or information provided by Petro-SIM. For typical refinery streams, the hypothetical properties are determined by the assay and not your input. Edit Properties Petro-SIM gives you the flexibility of viewing and modifying properties for traditional and hypothetical components. The Editing Properties for Component view can be accessed these levels: l l Component level. Double click any component or right-click and select View. In the component property view, click Edit Properties. Fluid Package level. Click Edit Properties on the Fluid Package view. You can view properties specific to input streams of the case at the stream level. The properties displayed typically correspond to the refinery assay associated with the stream, and may be very different from the default pure component properties shown for components in the basis environment. The Editing Properties for Component view displays the selected component or fluid package components. The properties can be sorted using the Sort By group on any level. Sort By Description Property Name Sort through properties by Property Name. Group Sort through properties by Groups. This includes Thermo, Prop Pkg, Physical, Cold, Solid, etc. Type Sort through Point or Curve properties. Modify Status Sort through properties that are modified in the specific Component, Fluid Package, or Stream. v 247 Chapter 4: Simulation Basis Environment You can edit properties on the component or fluid package levels. The Component level is the highest and lets you edit properties throughout your case. Any changes at this level correspond to a global change to all fluid packages using the particular component. The initial value stored at this level for any given component is considered the default property value. Reset Options at the Component level Component Level Reset Description Reset property to library default Resets the current property to the library or original default value for this component. This button is active only if the property is modified on the component level. Reset all properties to library defaults Resets all properties to library or original default values for this component. This button is active only if a component is modified on the component level. Reset property for all uses of component Clears local changes to the selected property for all uses of this component. Users are defined by changes in the Fluid Package and stream levels. Reset all properties for all uses Clears local changes to all properties for all uses of this component. of component Users are defined by changes in the Fluid Package and stream levels. 248 v Components The second level is the fluid package level that lets you edit properties specific to a fluid package. This gives the flexibility of having different property values for different fluid packages throughout the case. Any changes at this level correspond to a change for any flowsheet using this fluid package. Reset Options at the Fluid Package level Fluid Pkg Level Reset Description Reset property to component default Clears the selected property within this fluid package and resets it to the component level value. Reset all properties to component defaults Clears all changed properties within this fluid package and resets them to the component level values. Reset property for all uses of fluid package Clears local changes to selected property for all uses of this fluid package. The use is defined as the stream level property selected, which is overwritten with current fluid package value. Reset all properties for all uses of fluid package Clears local changes to all properties for all uses of this fluid package. The uses are defined as the stream level properties, which are overwritten with current fluid package values. v 249 Chapter 4: Simulation Basis Environment Pure Component Property View In this example, Methane and Carbon are used by clicking the View Component button, which opens the following traditional pure component and Solid pure component property views, respectively: You can also view a component by right-clicking it and selecting View. These property views are made up of these tabs: ID The ID tab is the first tab in the property view. The black values in the Component Identification group represent information that is provided by Petro-SIM. The User ID Tags are used to identify your component by your specified tag number. You can assign multiple tag numbers to each component. Critical and Props The Critical tab displays Base and Critical Properties. The properties for pure components are supplied by Petro-SIM and are read-only. You can edit these properties using the Edit Properties button. The Component Property view for solid components does not have critical properties and therefore does not require the Critical tab. An alternate tab called the Props tab, which displays default values for Solid properties and Coal Analysis, is included. These properties can also be edited using the Edit Properties button. Point Additional Point properties are given for the Thermodynamic and Physical Props and the Property Package Molecular Props. The pure component properties differ from the solid properties. The solid properties depend only on the Heat of Formation and Combustion. These properties may be altered by selecting Point properties in the Edit Properties view. 250 v Hypotheticals TDep The Temperature Dependent Properties for pure components are shown in this tab. Petro-SIM provides the minimum temperature, maximum temperature and coefficients for each of the three calculation methods. The difference between pure components and solid pure components is that solids do not participate in VLE calculations. Their vapour pressure information is, by default, set to 0. Since solid components do affect heat balances, the specific heat information is used. The properties may be edited by selecting the Edit Properties button. UserProp The UserProp tab displays user specified properties. User properties must be specified on the User Properties tab in the Simulation Basis Manager view. Once a user property is specified there, you can view and edit the properties on this component view. Refer also to Hypothetical Component Property View and Solid Hypothetical Propert y View. Hypotheticals Hypothetical components can be pure components, defined mixtures, undefined mixtures, or solids. Use the Hypothetical tab, also called the Hypo Manager, on the Simulation Basis Manager to create non-library or hypothetical components. You can convert or clone Petro-SIM library components into hypotheticals and modify the library values. To open the Hypo Manager, click the Hypotheticals tab on the Simulation Basis Manager. v 251 Chapter 4: Simulation Basis Environment You can also open the Hypo Manager from the Components List view. Select Hypotheticals and then click Hypo Manager. In Petro-SIM, Hypothetical components exist independent of the Fluid Package. When a Hypothetical is created, it is placed in a Hypothetical Group. You can create new Hypothetical Groups and move hypothetical components into groups. Because Hypothetical components are not associated with a particular fluid package, multiple fluid packages can share hypotheticals. Hypothetical Groups can also be imported and exported, making them available to any simulation case. A wide selection of estimation methods are provided for the various Hypothetical groups (hydrocarbons, alcohols, etc.) for the Hypothetical component in the simulation. Methods are also provided for estimating the interaction binaries between hypotheticals and library components. The Hypothetical view contains buttons to help you manage and create hypotheticals in these two areas. See Create a Hypothetical Group for a general procedure or to Tutorial: Adding a Hypothetical for an exercise that demonstrates how to create a hypothetical. Hypothetical Groups The Hypothetical Groups list displays all the hypothetical groups installed in the simulation. Use this button... To... View View a selected Hypothetical Group in the Tabular Hypothetical Input view. Add Create a new Hypothetical Group. Delete Delete a selected Hypothetical Group from the case. Translocate Search through all hypothetical components in the case, and if duplicate components are found, Petro-SIM places them in a separate group where they can be deleted. This is useful when large cases have many templates/fluid packages imported with many duplicate hypotheticals in the case. Import Import Hypothetical Groups from a file (*.hyp). Export Export selected Hypothetical Groups and save them to a file (*.hyp). Hypothetical Quick Reference The Hypothetical Quick Reference group includes all Hypotheticals installed in the Basis 252 v Hypotheticals Environment (Hypo Name column) and their Hypo Groups (Group Name column). Use this button... To... View Hypo Open the property view for the selected Hypothetical. View Group Open the Tabular Hypothetical Input view for the selected Hypothetical. Move Hypos Move hypothetical components from one Hypo Group to another. Clone Comps Use a copy of a selected library component as the basis for defining a Hypothetical. See Clone Library Components. Create a Hypothetical To define or modify a hypothetical, you can follow these basic steps: Create a new Hypo Group 1. From the Hypotheticals tab, click Add in the Hypothetical Groups group. Petro-SIM automatically adds a new group to the list and names this group HypoGroupN (wher N represents a number). You must create a Hypothetical Group before you can install a Hypo component. 2. Enter the details for the new hypothetical group in the Tabular Hypothetical Input view as follows: a. Select the Component Class for the Hypo Group. b. Set the Estimation Methods for the Group (optional). Optionally, to convert library components to hypo components, click Clone Library Components Adding Hypo Components to the Hypo Group 1. From the Individual Hypo Controls group, choose one of the following display properties: l Base Properties - refer to the Critical tab of the Hypothetical Component Property view. l Vapour Pressure - refer to TDep tab of the Hypothetical Component Property view. v 253 Chapter 4: Simulation Basis Environment 2. Do one of the following to add a new Hypo: l Click Add Hypo to add a new hypothetical component l Click Add Solid to add a new solid hypothetical component. A new Hypothetical is added to the grid. 3. Enter the minimum properties for the hypothetical component. If the hypothetical component is defined as a hydrocarbon, the appropriate default correlations can be used to calculate its Critical Properties or any other missing information. Its interaction parameters are also calculated based on the estimated Critical Properties. To estimate the component's Critical Properties, a minimum amount of information must be supplied. The more information you can supply, the more accurate the estimations are. Normal Boiling Point Minimum Required Information < 700°F (370°C) Boiling Point > 700°F (370°C) Boiling Point and Liquid Density Unknown API and Molecular Weight 4. To supply a UNIFAC structure for the Hypo (optional), click Show UNIFAC Builder. Tabular Hypothetical Input The Tabular Hypothetical Input view is used to create new or modify existing hypotheticals. The grid displays the estimated or known property values for the Hypotheticals in the Hypo Group. 254 v Hypotheticals Hypo Group Controls These buttons are used to set properties for the Hypo Group. The properties apply to all Hypo components added to the group. Option Description Group Name Displays the name for the Hypothetical Group. Petro-SIM provides a default name, HypoGroupN, which can be changed. Hypothetical components must reside inside a Hypothetical group. Component Class Select the class from the drop-down list to provide better estimation of the component properties. Every component in a Hypo Group must be of a common Component Class. Petro-SIM sets the class be Hydrocarbon by default. For the Component Class, there are varying levels of specificity. For example, under Alcohol, you can specify sub-classes of alcohols, such as Aliphatic, Aromatic, Cyclo and Poly. Using a stricter degree of component type helps select appropriate estimation methods, but it forces all components to be calculated using the same method. If you want to mix component classes (i.e., both Aliphatic and Aromatic inside the same Hypo Group), select the more general v 255 Chapter 4: Simulation Basis Environment Option Description Component Class of Alcohol. Estimation Methods Opens the Property Estimation view where you can select an estimation method for each property. The selected estimation method applies to all Hypotheticals in the Hypo Group. Estimate Unknown Props Estimates the unknown properties for all Hypothetical components in the Hypo Group, using the methods chosen on the Property Estimation view. Clone Library Comps Converts library components into hypothetical components. Notes Use to supply Notes and Descriptions for the Hypothetical Group. This is useful when exporting Hypo groups, because when they are imported later, the description appears with the Hypo group name. Individual Hypo Controls Button Description View Displays the Property View for the highlighted hypothetical component. Add Hypo Automatically adds a new hypothetical component to the group. Petro-SIM places the new Hypo in the table and names it according to the default naming convention (set in the Session Preferences). Add Solid Automatically adds a new solid hypothetical component to the group. Petro-SIM places the new Hypo in the table and names it according to the default naming convention (set in the Session Preferences). Delete Deletes the highlighted hypothetical component from the case. After deleting, a Hypo cannot be recovered. UNIFAC Opens the UNIFAC Component Builder, from which you can provide the UNIFAC Structure for the highlighted hypothetical component. Property Estimation Methods To open the Property Estimation view, click Estimation Methods on the Tabular Hypothetical Input view. 256 v Hypotheticals The Estimation Methods selected for the Hypo Group applies to all Hypotheticals in that group. For each property, specify an estimation method. 1. In the Property to Set Methods For, choose the property for which you want to set an Estimation Method. Petro-SIM initially sets all properties to the Default Method. 2. From the Estimation Method For Selected Property drop-down list, choose the estimation method from the available methods for the selected property. Refer to the table below. If you select Do Not Estimate as the estimation method, the property is not estimated. The Variables Affected by this Estimate list displays all variables affected by the selected estimation method. The following table lists each property, its Default Method, available estimation methods, and the Variables Affected by the estimate. Each property can have Do Not Estimate selected as its estimation method. Before installing any Hypotheticals into a Hypo Group, examine the Estimation Methods Petro-SIM uses to calculate the unknown properties for a hypothetical component. v 257 Chapter 4: Simulation Basis Environment Property Default Method Critical Temperature Lee-Kesler if ρLIQ > 1067 kg/m3 or NBP > 800 K Available Methods l l Bergman if NBP < 548.16 K and ρLIQ <850 kg/m3 l Cavett for all other cases l l l l l l l l l l l l l Critical Pressure Lee-Kesler if ρLIQ > 1067 kg/m3 or NBP > 800 K l l Bergman if NBP < 548.16 K and ρLIQ <850 kg/m3 l Cavett for all other cases l l l l l l l l l l Critical Volume Pitzer l l l Aspen Bergman Cavett Chen Hu Eaton Porter Edmister Group Contribution Lee Kesler Mathur Meissner Redding Nokay Riazi Dauber Roess PennState Variables Affected Critical Temperature Standard Liquid Density COSTALD_Variables ViscositThetas Standing Twu Aspen Bergman Cavett Edmister Group Contribution Lee Kesler Lydersen Mathur PennState Riazi Daubert Rowe Standing Twu Critical Pressure Group Contribution Pitzer Twu Critical Volume Standard Liquid Density COSTALD_Variables ViscositThetas Standard Liquid Density COSTALD_Variables ViscosityThetas Acentricity 258 v Lee-Kesler for Hydrocarbon l Bergman w Hypotheticals Property Default Method Pitzer for all other cases Available Methods l l l l l Molecular Weight Bergman if NBP < 155°F Lee-Kesler for all other cases l l l l l l l l l Twu COSTALD_Variables ViscosityThetas Normal Boiling Point Standard Liquid Density Tc Pc w rg COSTALD_Variables ViscosityThetas HFForm UNIFAC_RQ Normal Boiling Point Gomez Thodos Lee Kesler Antoine Coefficient Standard Liquid Density l Bergman BergmanPNA Chueh Prausnitz Gunn Yamada Hariu Sage Katz Firuzabadi Lee Kesler Twu Whitson Yarborough Yen Woods l Cavett Ideal H Coefficient l Riedel for all other cases l Yen-Woods l l l l l l l l l l Ideal Gas Molecular Weight Standard Liquid Density ViscosityThetas Vapor Pressure Lee-Kesler for Hydrocarbon Liquid Density API Aspen Aspen Leastq Bergman Hariu Sage Katz Firoozabadi Katz Nokay Lee Kesler PennState l l Proprietary method GS_w l l Normal Boiling Point Edmister Lee Kesler Pitzer Pitzer Curl Robinson Peng Riazi Daubert Robinson Peng Twu Whitson l Variables Affected Cavett PRSV_kappa COSTALD_Variables v 259 Chapter 4: Simulation Basis Environment Property Default Method Enthalpy Available Methods l Falon Watson Group Contribution Lee Kesler Modified Lee Kesle l Group Contribution l l l Heat of Formation Joback for chemical structure defined in UNIFAC groups Variables Affected Heat of Formation Heat of Combustion For all other cases, this formula is used: H form(octane)MW MW (octane) Ideal Gas Gibbs Energy Proprietary method Heat of Vaporization Two Reference Fluid (using benzene and carbazole) Group Contribution Gibbs Coefficient Chen Pitzer Riedel Two Reference1 Vetere Cavett Variables Proprietary Letsou Stiel ViscosityThetas Tabular Variables l Brock Bird Gray Hankin Sprow Prausnitz l Default Method Critical Temperature l l l l l l Liquid Viscosity Letsou Stiel for nonHydrocarbon or NBP < 270 K is used l l for Hydrocarbon and NBP < 335 K, NBS viscosity is used all other cases, Twu is used Surface Tension Brock Bird l l l Radius of Gyration Proprietary method Critical Pressure Normal Boiling Point Molecular Weight Standard Liquid Density 260 v Hypotheticals When defining Hypothetical components, you cannot select the estimation method for some properties. Petro-SIM determines the proper method based on information you provide. These properties and their respective default methods are: Property Default Estimation Method Liquid Enthalpy The previously calculated Liquid Heat Capacity is used. Vapour Enthalpy Liquid Enthalpy + Enthalpy of Vaporization Chao Seader Molar Volume If T > 300 K, Molar Volume from COSTALD @ 25°C and 1 atm c is used. For all other cases, ρLIQ @ 60°F is used. Chao Seader Acentricity Component acentric factor is used Chao Seader Solubility Parameter If T > 300K, Watson type Enthalpy of Vaporization is used. c For all other cases, values of 5.0 are used. Cavett Parameter Two Reference Fluid1 method (using benzene and carbazole) Dipole Moment No estimation method available sets value equal to zero. Enthalpy of Combustion No estimation method available sets value to <empty>. COSTALD Characteristic Volume If NBP < 155°F, Bergman is used Liquid Viscosity Coefficients A and B For non-Hydrocarbon or NBP < 270 K, Letsou Stiel is used all other cases, Katz-Firoozabadi is used for Hydrocarbon and NBP < 335 K, NBS viscosity is used all other cases, Twu is used. Vapour Viscosity Chung PRSV Kappa1 Vapour Pressure from Antoine’s Equation Kfactor1 Vapour Pressure from Antoine’s Equation UNIFAC Component Builder Most estimation methods require a UNIFAC structure. It may be that either the property or another property affected by the estimation procedure requires the chemical structure. 1. To set the UNIFAC structure, click: l Show UNIFAC Builder on the Tabular Hypothetical Input view 1Reid, R.C., Prausnitz, J.M., Poling, B.E., The Properties of Gases & Liquids, 4th edition, McGraw-Hill, 1987. v 261 Chapter 4: Simulation Basis Environment or l Structure Builder on the ID tab of the Hypothetical Component Property view 2. In the UNIFAC Component Builder view, use one of the following methods to build the UNIFAC structure. l Select one or more Sub Groups in the Available UNIFAC Group list, and then click Add Groups to move the sub groups to the UNIFAC Structure group. l l If you know the sub group structure, in the UNIFAC Structure group, enter a sub group number directly in the Sub Group column and the number of Bonds in the How Many column. If you know the chemical structure of the molecule, type it in the UNIFAC Structure field. To add multiples of a sub group, type the number of bonds followed by a space and the sub group name. For example, type 3 CH2 to add three CH2 sub groups to the UNIFAC structure. 3. As you add sub groups, Petro-SIM displays the number of Free Bonds available. When the UNIFAC structure is complete, it displays 0 (zero) and the status message changes to Complete (on a green background). 262 v Hypotheticals 4. Petro-SIM automatically calculates the UNIFAC Calculated Base Properties and UNIFAC Calculated Critical Properties based on the new structure. The UNIFAC Component Builder view is made up of these objects: Objects Description UNIFAC Structure Displays the Type and Number of Sub Groups in the UNIFAC Structure. Group Add Group(s) Adds selected Sub Groups from the Available UNIFAC Groups list box to the UNIFAC Structure group. Delete Group Deletes selected Sub Groups from the UNIFAC Structure group. Free Bonds Displays the number of free bonds available in the UNIFAC Structure. When the structure is complete, it displays 0 (zero). Status Bar Indicates the status of the UNIFAC Structure: l l l Incomplete in red Complete in green Multi-Molecules in yellow Available UNIFAC Displays all available UNIFAC component sub groups. Groups UNIFAC Structure Displays the chemical structure of the molecule. field v 263 Chapter 4: Simulation Basis Environment Objects Description UNIFAC Calculated Base Properties Displays properties such as Molecular Weight, the UNIQUAC R parameter and the UNIQUAC Q parameter for a UNIFAC Structure with at least one sub group. UNIFAC Displays the critical properties for a UNIFAC Structure with at least one sub Calculated Critical group. Properties Clone Library Components To convert Petro-SIM library components into Hypotheticals, click Clone Library Comps on the Tabular Hypothetical Input view. 1. In the Convert Library Comps to Hypothetical Comps view, select any library component in the Fluid Package to convert to a Hypothetical. 2. Select the Target Hypo Group, where the new Hypo is to be cloned. 3. If you want to replace all instances of the source component with the new Hypo, check Replace All Instances. 4. Click Convert to Hypo(s) to complete the conversion. 5. The new Hypo appears in the Hypo Components group with an asterisk after its name, signifying that it is a hypothetical. 6. Close the view to return to the Tabular Hypothetical Input view. This view is made up of two sections, the Source Components group and the Hypo Groups. 264 v Hypotheticals Object Description Component Lists Select the component list that contains the library component you want to clone. Available Library Select the component you want to convert into a hypothetical. Comps Replace ALL Instances Check to replace the library component with the Hypo in every Fluid Package that contains the library component. If you only want to replace the library components in the highlighted Fluid Package, do not check this option. Hypo Group Select the Hypothetical Group in which you want the converted library component placed. Hypo Components Displays all the hypothetical components present in the selected hypothetical group. When a library component is converted into a hypothetical, it is added to the list with an asterisk following its name. Move Hypos Hypothetical components are created in Hypo Groups and are stored as part of the group. After adding a hypothetical component to a group, you may want to move it to another group. 1. To move a hypothetical component from one group to another, click Move Hypo in the Hypothetical Quick Reference group. 2. In the Move Hypothetical Comps view, select the Hypo you want to move from the Hypo Components group. 3. Select the Target Hypo Group to which the component is being moved, or click Add New Hypo Group to create a new Hypo Group for it. 4. Click Switch to Group, which becomes enabled when you have items selected in both the Hypo Components and Target Hypo Group lists. 5. When you are finished moving components, close the view and return to the Hypotheticals tab. v 265 Chapter 4: Simulation Basis Environment Hypothetical Component Property View Hypotheticals, like library components, have their own property view. Once inside, you can add or modify information, or examine the results of the estimations. You can access the property view for the Hypo component from these views: l l l Hypotheticals tab - double-click the component, or highlight it and click View Hypo. Tabular Hypothetical Input view - double-click the component, or highlight it and click View. Components tab - open the Component List view, highlight the component, and click View Component or right-click the name and select View In all the property view tabs, information is displayed in red, blue and black. Values displayed in red are estimated by Petro-SIM and values displayed in blue are entered by you. Black values represent calculated values or information you cannot modify (i.e., Family/ Class on the ID tab). You can supply values for any of the component properties or overwrite values estimated by Petro-SIM. 1. Enter the properties for the Hypothetical component on these tabs: l ID l Critical l Point l TDep l UserProp 266 v Hypotheticals 2. After entering adequate estimation parameters, select Estimate Unknown Properties to complete the hypothetical estimation. If you change a specified value, all properties previously estimated using that specification are erased. Click Estimate Unknown Props again to recalculate the properties. 3. To edit the hypo component properties at the component level, click Edit Properties. Refer also to Pure Component Property View and Solid Hypothetical Property View. ID Use the ID tab on the Hypothetical Component Property View to view or modify the component's identification information. Click Structure Builder to open the UNIFAC Component Builder where you can define the structure of the Hypo. The UNIFAC Structure field displays the molecular composition of the Hypo, or you can enter and modify the structure. Check Synthesis Component to add the Hypo to the synthesis component list. Critical The Critical tab of the Hypothetical Component Property view displays the base and critical properties. This is the same information displayed on the Tabular Hypothetical Input when the Base Properties option is selected. You can enter or modify the Base Properties. v 267 Chapter 4: Simulation Basis Environment Click Estimate Unknown Props, to calculate the Critical Properties. Point The Point tab on the Hypothetical Component Property view displays Additional Point Properties for the hypothetical. Select one of the following options to toggle between viewing the following information. Thermodynamic and Physical Properties Petro-SIM estimates Thermodynamic and Physical properties for the Hypo based on the base property data entered and the selected estimation methods. 268 v Hypotheticals The Heat of Comb field is <empty> indicating that Petro-SIM cannot estimate this value with the given information. Petro-SIM lets you specify a value for this property. Property Package Molecular Props The Property Package Molecular properties for the Hypo are estimated based on the selected estimation method for each property. v 269 Chapter 4: Simulation Basis Environment Some fields in this view are <empty> indicating that Petro-SIM cannot estimate these values with the information given. Petro-SIM lets you specify values for these properties. TDep The TDep tab on the Hypothetical Component Property view displays the temperature dependent properties for the hypothetical, the pressure and temperature units on which the equation is based, and the form of the equation. Select one of these options to view the information: Vapour Enthalpy The Vapour Enthalpy calculation is performed on a Mass Basis. The reference point for the equation is an ideal gas at 0K. The units for Mass Vapour Enthalpy and Temperature are kJ/kg and degrees Kelvin, respectively. When required, the Vapour Enthalpy equation is integrated by Petro-SIM to calculate entropy. If enthalpy coefficients are entered, a constant of integration, g, should be supplied along with the other coefficients. Specify this value in the g coefficient field. Petro-SIM has estimated the Minimum and Maximum Temperatures. Below the temperature range are values for the Vapour Enthalpy equation coefficients (from a to g). Petro-SIM estimates the coefficients, but you may change any of the values. 270 v Hypotheticals Vapour Pressure The Vapour Pressure is calculated using the Modified Antoine equation. Petro-SIM estimates the Minimum and Maximum Temperature values based on the supplied properties and estimation methods. The units used for Pressure and Temperature are kPa and degrees Kelvin, respectively. The bottom section of this view displays the values for each of the Antoine equation coefficients (from a to f). Petro-SIM estimates the coefficients, but you can modify these values. Gibbs Free Energy The Gibbs Free Energy calculation uses Enthalpy as its property type and is performed on a Molar Basis. The basis for the equation is ideal gas at 25°C. Petro-SIM estimates the Minimum and Maximum Temperature values. v 271 Chapter 4: Simulation Basis Environment The units for Molar Enthalpy and Temperature are kJ/kg mole and degrees Kelvin, respectively. The bottom section of the view displays the values for each of the Gibbs Free Energy equation coefficients (from a to c). Petro-SIM estimates the Gibbs Free Energy coefficients if you supply the UNIFAC structure and enter the Ideal Gas Gibbs Free Energy at 25°C in the a coefficient cell. UserProp The UserProp tab on the Hypothetical Component Property view displays user specified properties. User properties must be specified on the User Properties tab in the Simulation Basis Manager view. 272 v Hypotheticals When a user property is specified there, you can view and edit the properties on this component view. Solid Hypothetical Property View Solid hypotheticals can be added to any Hypo Group, regardless of the Group Type. In the Individual Hypo Controls group of the Tabular Hypothetical Input view, click Add Solid. When you install a solid hypo, the Base Properties cells on the Tabular Hypothetical Input view are displayed as <empty>. Solids do not take part in VLE calculations, but they do have an effect on heat balance calculations. ID tab The ID tab of the Solid Hypo component property view is the same as that for other Hypo components except that the User Props tab is not required. The Class type has no effect on the values calculated for the solid component. v 273 Chapter 4: Simulation Basis Environment Props tab The Props tab displays the basic properties of the component in these groups: Solid Properties The minimum information that must be supplied includes the Molecular Weight and Density. The appropriate units can also be specified in the cell as shown. The other Solid Properties are described below: Solid Property Description Diameter Particle diameter, if not supplied this defaults to 1 mm when the remaining properties are estimated. Sphericity Value between 0 and 1 , with 1 being perfectly spherical. Area/Unit Volume Measure of the surface area of the particle as a function of the particle volume. 274 v Hypotheticals Coal Analysis You can also provide the results of a Coal Analysis on a percentage basis for the listed components. Point tab The only information on the Point tab relevant to the Solid is the Heat of Combustion and Heat of Formation. This information is required only if you plan to use a Solid component as part of a reaction. TDep tab Because solid Hypos do not participate in VLE calculations, their vapour pressure information is, by default, set to zero. Since solid components affect Heat Balances, the Specific Heat information can either be estimated by Petro-SIM, or supplied. While other Hypotheticals use the Ideal Gas Enthalpy coefficients, solids use the Specific Heat Capacity. v 275 Chapter 4: Simulation Basis Environment TDep tab Because solid Hypos do not participate in VLE calculations, their vapour pressure information is, by default, set to zero. Solid components affect Heat Balances,so the Specific Heat information can either be estimated by Petro-SIM, or supplied. While other Hypotheticals use the Ideal Gas Enthalpy coefficients, solids use the Specific Heat Capacity. Refer also to Hypothetical Component Property View and Pure Component Property View. 276 v Hypotheticals Tutorial: Adding a Hypothetical In this tutorial, a hypothetical Ethanol component is defined and the results are compared to the library Ethanol component using the Wilson property package. The ethanol hypothetical component is defined as having a boiling point of 78.25°C and a specific gravity of 0.789. Create the Ethanol Hypo 1. Open a new case in Petro-SIM. 2. From the Simulation Basis Manager, select the Hypotheticals tab. 3. In the Hypothetical Groups group, click Add to create a new Hypothetical Group. Petro-SIM automatically names this group HypoGroup1. You can change the name later, if desired. You must install a Hypothetical Group before you can install a Hypo component. Add and define the Hypothetical components for the group 1. In the Tabular Hypothetical Input view, enter HypoAlcohol as the new Group Name. v 277 Chapter 4: Simulation Basis Environment 2. On the Home tab, select Units and choose SI as the units for the case. 3. From the Component Class drop-down, choose Alcohol. Install a Hypothetical component 1. In the Individual Hypo Controls group, click Add Hypo. This adds a Hypothetical component and names it Hypo20041*. 2. Enter a new name for this component by typing HypoEtoh in the Name cell. 3. In the NBP cell, enter the normal boiling point of the component as 78.25°C. 4. The specific gravity for the hypothetical component is 0.789. In the Liq Density cell, enter 0.789 and select the SG_60/60api units. A liquid density of 787.41 kg/m3 is calculated by Petro-SIM. 278 v Hypotheticals 5. Although Petro-SIM could estimate the unknown properties for HypoEtoh with only the NBP and Liquid Density, more accurate results are obtained if the component structure is supplied. The chemical formula of ethanol is C H OH and it is comprised of the groups 2 5 CH , CH and OH. 3 2 a. Click Show UNIFAC Builder to open the UNIFAC Component Builder. b. Select CH3 in the Available UNIFAC Groups list, and then click Add Group (s). c. In the UNIFAC Structure group, the Sub Group cell is 1 and, by default, Petro-SIM assigns the value 1 to the How Many cell. The number is valid, since this is the number of CH groups required. The number of Free Bonds increased 3 to 1 with the addition of the CH3 Sub Group. v 279 Chapter 4: Simulation Basis Environment d. To add the CH group, select CH2 in the Available UNIFAC Groups list and then 2 click Add Group(s). Only 1 sub group is required, so the default is acceptable. e. Because the OH group isn't immediately visible in the list of Available UNIFAC Groups, in the UNIFAC Structure field, type OH at the end of the existing structure (CH3CH2) and press ENTER. When the UNIFAC Structure is complete, Petro-SIM calculates the UNIFAC Calculated Base Properties and UNIFAC Calculated Critical Properties. The Status message displays Complete when there are 0 Free Bonds. f. Close the view to return to the Tabular Hypothetical Input view. 6. Petro-SIM can now use the existing information (NBP, Liquid Density and UNIFAC structure) to estimate the remaining properties for the Hypothetical component. Examine the Estimation Method that Petro-SIM uses 1. Click Estimation Methods to open the Property Estimation view. 280 v Hypotheticals 2. You can, optionally, change the estimation method for any property. In this example, all properties use the Default Method. 3. Click the Close icon to return to the Tabular Hypothetical Input view. 4. Click Estimate Unknown Props to use the specified methods to estimate the unknown properties for the component. The molecular weight for the hypothetical is the same as the molecular weight for ethanol, 46.07, since the UNIFAC structure is used for the Hypo component. Specified values are displayed in blue and Petro-SIM estimated values are displayed in red. 5. You can examine all properties for the Hypo through its property view. Double-click the hypothetical component name, HypoEtoh, to open the Hypothetical Component Property View. v 281 Chapter 4: Simulation Basis Environment 6. Click the Close icon to return to the Tabular Hypothetical Input view. 7. Click the Close icon to return to the Hypotheticals tab of the Simulation Basis Manager. The Ethanol Hypothetical is created. Compare the hypothetical to the library component 1. From the Simulation Basis Manager, Fluid Pkgs tab, click Add to install a new Fluid Package. 2. On the Set Up tab, select Wilson as the Property Package and close the Fluid Package view. 3. Click the Components tab on the Simulation Basis Manager. 4. Click Add in the Simulation Basis Manager to create a new component list. 5. I n the Components List view, select Ethanol in the Components Available in the Component Library list and click Add Pure to add it to the Selected Component List. 6. Select Hypothetical and from the Available Hypo Components group, select HypoEtoh*. Click Add Hypo to add it to the Selected Components list. 7. Click Hypo Manager to return to the Hypotheticals tab, and then click the Fluid Pkgs tab. 8. Select the Wilson package, and the click View to open the Fluid Package property view 282 v Hypotheticals 9. On the Binary Coeffs tab, click Unknowns Only in the Coeff Estimation group. 10. 11. 12. 13. Close the Fluid Package property view. Click Return to Simulation Environment to enter the Main Environment. Open the Workbook (CTRL+W), select Main and then click View. Create a stream named Pure in the Streams tab of the workbook. a. Enter a vapour fraction of 0 and a pressure of 1 atm. b. Open the Streams property view (double-click the stream name in the workbook) and select the Compositions page. c. Enter 1 for the mole fraction of Ethanol and 0 for HypoEtoh*. 14. In the Workbook, create a second stream name, Hypo. a. Enter a vapour fraction of 0 and a pressure of 1 atm for the stream. b. Open the Streams property view, and enter a mole fraction of 1 for HypoEtoh* and 0 for Ethanol. When you have specified these two streams, Petro-SIM calculates the bubble point temperature for each stream. The Conditions tab of the property view for both streams are shown below. v 283 Chapter 4: Simulation Basis Environment Oil Manager The Oil Manager tab on the Simulation Basis Manager view is the gateway to the Oil Characterization Environment. Before you can enter the environment from the Oil Manager, you must have at least one Fluid Package defined in the case. Select the Oil Manager tab and then click Enter Oil Environment. The Oil Characterization Environment displays the fluids in your simulation. Reactions The Reaction Manager, which is located on the Reactions tab of the Simulation Basis Manager, provides a location from which you can define an unlimited number of reactions and attach combinations of these reactions in Reaction Sets. The Reaction Sets are then attached to Unit Operations in the Flowsheet. Reactions of library components are defined inside the Reaction Manager. The Reaction Manager lets you perform the following: l l l 284 v Create a new list of components for the Reactions or simply use the fluid package components. Add, Edit, Copy or Delete Reactions and Reaction Sets. Attach Reactions to various Reaction Sets or attach Reaction Sets to multiple Fluid Reactions l Packages, thus eliminating repetitive procedures. Import and Export Reaction Sets. Reaction Component Selection The Reactions tab is made up of three main groups: Group Description Rxn Components Displays all components available to the Reaction Manager and the Add Comps button. Reactions Displays a list of the defined reactions and four buttons available to help define reactions. Reaction Sets Displays the defined reactions sets, the associated fluid packages and several buttons that help to define reaction sets and attach them to fluid packages. Each of the main groups in the Reaction Manager is examined in more detail. In this section, the Rxn Components group is described. The features in the Reactions group and Reaction Sets group are detailed in subsequent sections. There are three distinct ways in which components can be made accessible to Reactions in the Reaction Manager: You can add components on the Component tab of the Simulation Basis Manager. The components are added to the component list and are available in the Rxn Components group to be attached to the Reaction Set. These components are also included in the Fluid Package depending on the component list selected for the package. v 285 Chapter 4: Simulation Basis Environment You can install components directly in the Reaction Manager without adding them to a specific component list by clicking Add Comps. The Component List view appears where you can add reaction components. These components appear automatically in the master component list, but not in the component list selected for the fluid package. When a Reaction Set (containing a Reaction which uses the new components) is attached to a fluid package, the components that are not present in the fluid package are automatically transferred. Refer to Reaction Sets for details on installing a fluid package. You can select an Equilibrium Reaction from the Library tab of the Equilibrium Reactor property view. All components used in the reaction are automatically installed in the Reaction Manager. Once the Reaction Set (containing the Library reaction) is attached to a Fluid Package, the components are automatically transferred to the Fluid Package. Adding Components from Basis Manager With this method of component selection, components are selected on the Components tab from the Simulation Basis Manager. Add a component list by clicking the Add button. From the Component List View, select the components that are required for the reaction. This is similar to adding components to a component list for a particular fluid package or case. All components that are selected are displayed and available in the Rxn Components group of the Reaction Manager. Selections Within the Reaction Manager Components can be made available prior to the creation of Reactions by directly selecting them within the Reaction Manager. By selecting the components in the Reaction Manager, you're not required to transfer component information from the fluid package. The components appear in the Master Component list, but not in the component list. Once a Reaction Set is attached to a Fluid Package, Petro-SIM automatically transfers all of the components contained within the Reaction(s) to the fluid package. The components listed in the Selected Reaction Components group are available to any Reaction that you create. At least 1 Fluid Package must exist before components can be transferred from the Reaction Manager. To begin a New Case: 1. Click the New Case icon on the toolbar. 2. On the Fluid Pkgs tab of the Simulation Basis Manager, click the Add button. A new Fluid Package is created and its property view opens. Close the Fluid Package property view. 3. Move to the Reactions tab. Click the Add Comps button in the Rxn Components group and the Component List view is displayed. 286 v Reactions 4. Select either traditional or hypothetical components. The procedure for selecting components is similar to the selection of components for the fluid package. 5. Return to the Reaction Manager to create the Reaction(s) and install the Reaction(s) within a Reaction Set. Reactions and Reaction Sets for details. 6. Attach the Reaction Set to the fluid package created in Step #2. See Adding a Reaction Set to a Fluid Package for details. All components used in the Reaction(s) that are contained within the Reaction Set are now available in the Fluid Package. Library Reaction Components When a Library Equilibrium Reaction is selected, all of its constituent components are automatically added to the Reaction Manager. You can then use the components in the Rxn Components group of the Reaction Manager to define other reactions. Library reactions can be installed prior to the addition of components to the case. You aren't required to add components using the Component List view or Reaction Manager. To add a Library reaction, perform the following tasks: 1. From the Reaction Manager, click the Add Rxn button in the Reactions group. 2. Highlight Equilibrium from the Reactions view and click the Add Reaction button. 3. Move to the Library tab of the Equilibrium Reaction property view and select a reaction from the Library Equilibrium Rxns group. 4. Click the Add Library Rxn button. All library information concerning the reaction is transferred to the various tabs of the Equilibrium Reaction property view. The components used by the reaction are now shown in the Rxn Components group of the Reaction Manager. v 287 Chapter 4: Simulation Basis Environment Reactions In Petro-SIM, a default reaction set, the Global Rxn Set, is present in every simulation. All compatible reactions that are added to the case are automatically included in this set. A Reaction can be attached to a different set, but it also remains in the Global Rxn Set unless you remove it. To create a Reaction, click the Add Rxn button from the Reaction Manager. Refer to Reaction Sets for more information. The following table describes the types of Reactions that can be modelled in Petro-SIM: Reaction Type Requirements Conversion Requires the stoichiometry of all the reactions and the conversion of a base component in the reaction. Equilibrium Requires the stoichiometry of all the reactions. The term Ln(K) may be calculated using one of several different methods, as explained later. The reaction order for each component is determined from the stoichiometric coefficients. Kinetic Requires the stoichiometry of all the reactions, as well as the Activation Energy and Frequency Factor in the Arrhenius equation for forward and reverse (optional) reactions. The forward and reverse orders of reaction for each component can be specified. Heterogeneous Catalytic Requires the kinetics terms of the Kinetic reaction as well as the Activation Energy, Frequency Factor and Component Exponent terms of the Adsorption kinetics. Simple Rate Requires the stoichiometry of all the reactions, as well as the Activation Energy and Frequency Factor in the Arrhenius equation for the forward reaction. The Equilibrium Expression constants are required for the reverse reaction. Each of the reaction types requires that you supply the stoichiometry. To assist with this task, the Balance Error tracks the molecular weight and supplied stoichiometry. If the reaction equation is balanced, this error is equal to zero. If you provided all of the stoichiometric coefficients except one, you may select the Balance button to have Petro-SIM determine the missing stoichiometric coefficient. Reactions can be on a phase specific basis. The Reaction is applied only to the components present in that phase. This allows different rate equations for the vapour and liquid phase in same reactor operation. 288 v Reactions Manipulating Reactions From the Reaction Manager, you can use the buttons in the Reactions group to manipulate reactions. The buttons are listed and described in the table below. To object inspect a reaction in the Reactions group, you can select View or Delete from the menu. Button Command View Rxn Accesses the property view of the highlighted reaction. Add Rxn Accesses the Reactions view, from which you select a Reaction type. Delete Rxn Removes the highlighted reaction(s) from the Reaction Manager. Copy Rxn When selected, the Copy Reactions view appears where you can select an alternate Reaction Type for the reaction or duplicate the highlighted reaction. Conversion Reaction The Conversion Reaction requires the Stoichiometric Coefficients for each component and the specified Conversion of a base reactant. The compositions of unknown streams can be calculated when the Conversion is known. The Conversion Reaction view is made up of these tabs: l l Stoichiometry Basis By default, conversion reactions are calculated simultaneously. You can specify sequential reactions using the Ranking feature. For more details, see Reaction Sets. Consider the Conversion reaction: b a c a d a A + B⇒ C+ D where: a, b, c, and d are the respective stoichiometric coefficients of the reactants (A and B) and products (C and D). A is the base reactant and B is not in a limiting quantity. In general, the reaction components obey the following reaction stoichiometry: N A = N A 0(1 − XA) b N B = N B 0 − N A 0XA a v 289 Chapter 4: Simulation Basis Environment NC = N C 0 + c a (N A XA) ND = N D 0 + d a (N A XA) 0 0 where: N = The final moles of component * (* = A, B, C and D) * N *0 = The initial moles of component * X = The conversion of the base component A A The moles of a reactant available for conversion in a given reaction include any amount produced by other reactions, as well as the amount of that component in the inlet stream(s). An exception to this occurs when the reactions are specified as sequential. Stoichiometry The Stoichiometry tab for a conversion reaction is shown in the figure below: For each Conversion reaction, you must supply the following information: Input Field Information Required Reaction Name A default name is provided which may be changed. The previous view shows the name as Rxn-1. Components The components to be reacted. A minimum of two components is required. You must specify a minimum of 1 reactant and 1 product for each reaction you include. Use the drop-down list to access the available components. The Molecular Weight of each component is automatically displayed. 290 v Reactions Input Field Information Required When you have supplied all of the required information for the Conversion Reaction, the status message will change from Not Ready to Ready. Stoichiometric Coefficient Necessary for every component in the reaction. The Stoichiometric Coefficient is negative for a reactant and positive for a product. You may specify the coefficient for an inert component as zero, which, for the Conversion reaction, is the same as not including the component in the table. The Stoichiometric Coefficient does not have to be an integer; fractional coefficients are acceptable. The Reaction Heat value is calculated and displayed below the Balance Error. A positive value indicates that the reaction is endothermic. Basis The Basis tab for a conversion reaction is shown in the figure below: On the Basis tab, you must supply the following: v 291 Chapter 4: Simulation Basis Environment Required Input Description Base Component Only a component that is consumed in the reaction (a reactant) may be specified as the Base Component (i.e. a reaction product or an inert component is not a valid choice). You can use the same component as the Base Component for a number of reactions, and it is quite acceptable for the Base Component of one reaction to be a product of another reaction. You have to add the Components to the reaction before the Base Component can be specified. Rxn Phase The phase for which the specified conversions apply. Different kinetics for different phases can be modelled in the same reactor. Possible choices for the Reaction Phase are: l Overall. Reaction occurs in all Phases. Vapour Phase. Reaction occurs only in the Vapour Phase. Liquid Phase. Reaction occurs only in the Light Liquid Phase. Aqueous Phase. Reaction occurs only in the Heavy Liquid Phase. l Combined Liquid. Reaction occurs in all Liquid Phases. l l l l Sequential Reactions may be modelled in one reactor by specifying the sequential order of solution. See Reaction Rank. Conversion Function Parameters Conversion percentage can be defined as a function of reaction temperature according to the following equation: Conv.(%) = C 0 + C1 * T + C 2 * T 2 This is the percentage of the Base Component consumed in this reaction. The value of Conv.(%) calculated from the equation is always limited within the range of 0.0 and 100%. The actual conversion of any reaction is limited to the lesser of the specified conversion of the base component or complete consumption of a limiting reactant. Reactions of equal ranking cannot exceed an overall conversion of 100%. 292 v Reactions To define a constant value for conversion percentage, enter a conversion (%) value for C only. Negative values for C and C means that the 0 1 2 conversion drops with increased temperature and vice versa. Equilibrium Reaction The Equilibrium Reaction view computes the conversion for any number of simultaneous or sequential reactions with the reaction equilibrium parameters and stoichiometric constants you provide. The Equilibrium Reaction view is made up of these tabs: l l l l l Stoichiometry Basis Keq Approach Library The Equilibrium constant can be expressed as follows: Nc vj    K= [Base]e   j  j =1   Π where: K = Equilibrium constant [Base]e j = Basis for component j at equilibrium v = Stoichiometric coefficient for the jth component j N = Number of components c This equation is only valid when Base (i.e., concentration) is at equilibrium composition. The equilibrium constant Ln(K) may be considered fixed, or calculated as a function of temperature based on a number of constants: Ln (Keq ) = a + b where: v 293 Chapter 4: Simulation Basis Environment a=A + B + C * ln(T ) + D * T T 2 4 5 b=E*T +F*T +H*T A, B, C, D, E, F, G, and H are constants defined on the Keq tab. Alternatively, you may supply tabular data (equilibrium constant versus temperature), and PetroSIM automatically calculates the equilibrium parameters for you. Ln(K) may also be determined from the Gibbs Free Energy. Stoichiometry The Stoichiometry tab for an equilibrium reaction is shown in the figure below. When you have supplied all of the required information for the Equilibrium Reaction, the status message changes from Not Ready to Ready. For each reaction, you must supply the following: Input Required Description 294 v Reaction Name A default name is provided, which may be changed by selecting the field and entering a new name. Components A minimum of two components is necessary. Specify a minimum of one reactant and one product for each reaction you include. The Molecular Weight of each component is automatically displayed. Stoichiometric Coefficient For every component in this reaction. The Stoichiometric Coefficient is negative for a reactant and positive for a product. You may specify the coefficient for an inert component as zero. The Stoichiometric Coefficient need not be an integer; fractional coefficients are acceptable. Reactions Basis The Basis tab for an equilibrium reaction contains two groups, the Basis and the Keq Source. Select one of four options as the Keq Source for the equilibrium reaction. Refer to Keq Tab for the results. Check Auto Detect to automatically change the Keq Source, depending on the Keq information you provide. For example, if you enter a fixed equilibrium constant, the Fixed Keq option is automatically selected. If you later add data to the Table tab, the Keq vs. T Table option is automatically selected. The Basis group requires the following information: Input Required Description Basis From the drop-down list in the cell, select the Basis for the reaction. For example, select Partial Pressure or Activity as the basis. Reaction Phase The possible choices for the Reaction Phase, accessed from the drop-down list, are the Vapour and Liquid Phases. Approach This input applies only to situations where more than one equilibrium reaction is used in a vessel. The temperature approach lets you adjust the equilibrium constant of the reaction by offsetting the temperature at which it's calculated. The approach value is an empirical adjustment that is used to modify the extent of reaction at equilibrium if the value of the equilibrium constant isn't well established. Positive or negative numbers can be input. v 295 Chapter 4: Simulation Basis Environment Input Required Description Minimum Enter the minimum and maximum temperatures for which the reaction Temperature and expressions are valid. If the temperature does not stay within the specified Maximum bounds, a warning message alerts you. Temperature Basis Units Enter the appropriate units for the Basis, or make a selection from the dropdown list. Keq Tab The Keq tab displays the following information depending on which option you selected as the Keq Source on the Basis Tab. Ln(Keq) Equation Ln(Keq), assumed to be a function of temperature only, is determined from the following equation: Ln (Keq ) = a + b where: a=A + B + C * ln (T ) + D * T T 2 4 5 b=E*T +F*T +H*T A, B, C, D, E, F, G, and H are constants defined on the Keq tab. Gibbs Free Energy The equilibrium constant is determined from the Ideal Gas Gibbs Free Energy Coefficients in the Petro-SIM library. 296 v Reactions Fixed K In this case, the equilibrium constant Keq is considered to be fixed, and is thus independent of temperature. You may specify either Keq or Ln(Keq) on the Keq tab. Check Log Basis to specify the equilibrium constant in the form Ln(Keq). K vs. T Table On the Keq tab, you can provide temperature and equilibrium constant data. Petro-SIM estimates the equilibrium constant from the pairs of data that you provide and interpolates when necessary. For each pair of data that you provide Petro-SIM calculates a constant in the Ln(K) equation. If you provide at least 4 pairs of data, all 4 constants A, B, C and D are estimated. v 297 Chapter 4: Simulation Basis Environment The constants may be changed even after they are estimated from the pairs of data you provide, simply by entering a new value in the appropriate cell. If you later want to revert to the estimated value, simply delete the number in the appropriate cell and it is recalculated. The term R2 gives an indication of the error or accuracy of the Ln(K) equation. It's equal to the regression sum of squares divided by the total sum of squares, and is equal to 1 when the equation fits the data perfectly. You can also provide the maximum (T Hi) and minimum (T Lo) temperatures applicable to the Ln (K) relation. The constants are always calculated based on the temperature range you provide. If you provide values in the K Table that are outside the temperature range, the calculation of the constants is not affected. Approach Under certain process conditions, an equilibrium reaction may not actually reach equilibrium. The Equilibrium reaction set uses 2 types of approach, Fractional and Temperature, to simulate this type of situation. You may select either 1 or both types of approaches for use in the simulation. 298 v Reactions The Approach tab contains 2 groups, the Fractional Approach and Temperature Approach groups. Temperature Approach isn't relevant for a fixed Keq source and thus the group doesn't appear when Fixed Keq is selected from the Basis tab. Both the Fractional Approach and Temperature Approach methods can be used to simulate an Equilibrium reaction that is a departure from equilibrium. For the Temperature Approach method, the Petro-SIM reaction solver will take into account the heat of reaction according to the equations listed. The direction of non-equilibrium departure depends on whether the reaction is endothermic or exothermic. The Fractional Approach method is an alternative to the Temperature Approach method and is defined according to the following equation: Feed − Product = Approach% − (Feed − Product)equilibrium The above equation could be interpreted as defining the actual reaction extent of the equilibrium as only a percentage of the equilibrium reaction extent of the reaction. In the solver, the value of Approach % is limited between 0 and 100%. Library The Library tab lets you add pre-defined reactions from the Petro-SIM Library. The components for the selected Library reaction are automatically transferred to the Rxn Components group of the Reaction Manager. v 299 Chapter 4: Simulation Basis Environment When you select a reaction, all data for the reaction, including the stoichiometry, basis, and Ln(K) parameters, are transferred into the appropriate location on the Equilibrium Reaction property view. To access a library reaction, highlight it from the Library Equilibrium Rxns group and click the Add Library Rxn button. Kinetic Reaction To define a Kinetic Reaction, it is necessary to specify the forward Arrhenius Parameters (the reverse is optional), the stoichiometric coefficients for each component, and the forward (and reverse) reaction orders. An iterative calculation occurs, that requires the Solver to make initial estimates of the outlet compositions. With these estimates, the rate of reaction is determined. A mole balance is then performed as a check on the rate of reaction. If convergence is not attained, new estimates are made and the next iteration is executed. rA = k * f (BASIS) − k ′ f ′ (BASIS) dNA dt The first equation relates the rate of reaction r with the reaction rate constants and the basis (for A example, concentration). The second equation is a mole balance on the unit operation. For steady state solutions, the right side is equal to zero. v F A 0 − FA + ∫ rAdV = The Kinetic Reaction view is made up of these tabs: l l l Stoichiometry Basis Parameters Stoichiometry When the Kinetic Reaction is selected, the following view is displayed: 300 v Reactions When you have supplied all of the required information for the Kinetic Reaction, the status message changes from Not Ready to Ready. For each reaction, you must supply the following information: Input Required Description Reaction Name A default name is provided, which may be changed at any time. Components Specify a minimum of one reactant and one product for each reaction you include. Access the available components using the drop-down list. The Molecular Weight of each Component is automatically displayed. v 301 Chapter 4: Simulation Basis Environment Input Required Description Stoichiometric Coefficient Necessary for every component in the reaction. The Stoichiometric Coefficient is negative for a reactant and positive for a product. The Stoichiometric Coefficient need not be an integer; fractional coefficients are acceptable. You may specify the coefficient for an inert component as zero, which in most cases is the same as not including the component in the list. You must include components that have an overall stoichiometric coefficient of zero and a nonzero order of reaction (i.e., a component that might play the role of a catalyst). The Kinetic Reaction, which lets you specify the Stoichiometric Coefficient and the order of reaction, makes it possible to correctly model this situation. Forward and Reverse Orders These are reaction orders. Petro-SIM initially fixes the orders of reaction according to the corresponding stoichiometric coefficient. These may be modified by directly entering the new value into the appropriate cell. For instance, in the following reaction: CO + Cl 2 ⇒ COCl 2 the kinetic rate law is rco = k[CO ][Cl 2]3/ 2 When the stoichiometric coefficients are entered for the reaction, Petro-SIM sets the forward orders of reaction for CO and Cl at 1. Enter 1.5 into the 2 Forward Order cell for Cl to correctly model the reaction order. 2 Thermodynamic Consistency Crucial to the specification of the reverse reaction equation is maintaining thermodynamic consistency so that the equilibrium rate expression retains the form of Equilibrium constant equation. Failure to do so may produce erroneous results from Petro-SIM. Consider the previously mentioned reaction: CO + Cl 2 ⇔ COCl 2 with the forward kinetics following the relationship: 3/2 rate forward = kf [CO ][Cl 2] Now suppose you want to add the reverse kinetic reaction. Since the forward reaction is already known, the order of the reverse reaction has to be derived in order to maintain thermodynamic consistency. Suppose a generic kinetic relationship is chosen: α β γ rate ckw rd = kf [CO ] [Cl 2] [COCl 2] 302 v Reactions where: α, β and γ represent unknown values of the order of the three components. Equilibrium is defined as the moment when: rate forward − rate backward = 0 The equilibrium constant K is then equal to: k kr K= f = [CO ]α [Cl 2] β [COCl 2]γ CO [Cl 2]3/ 2   To maintain the form of the equilibrium equation seen in the Equilibrium constant equation, K is also equal to: K= [COCl 2] [CO ][Cl 2] Now combining the two relationships for K found in the Equilibrium and Equilibrium constant K equations: [CO ]α [Cl 2] β [COCl 2]γ CO [Cl 2]3/ 2   = [COCl 2] [CO ][Cl 2] To maintain thermodynamic consistency: α must be 0, β must be 0.5 and γ must be equal to 1. Basis The Basis tab for a kinetic reaction is shown in the figure below: On the Basis tab, the following parameters may be specified: v 303 Chapter 4: Simulation Basis Environment Input Required Description Basis View the drop-down list in the cell to select the Basis for the reaction. If, for instance, the rate equation is a function of the partial pressures, select Partial Pressure as the Basis. Base Component Only a component that is consumed in the reaction (a reactant) may be specified as the Base Component (i.e. a reaction product or an inert component is not a valid choice). You can use the same component as the Base Component for a number of reactions, and it is quite acceptable for the Base Component of one reaction to be a product of another reaction. Reaction Phase The phase for which the kinetic rate equations apply. Different kinetic rate equations for different phases can be modelled in the same reactor. Possible choices for the Reaction Phase, available in the drop-down list, are: Overall, Vapour Phase, Liquid Phase, Aqueous Phase, and Combined Liquid. Minimum Temperature and Maximum Temperature Enter the minimum and maximum temperatures for which the forward and reverse reaction Arrhenius equations are valid. If the temperature does not remain within these bounds, a warning message alerts you during the simulation. Basis Units Enter the appropriate units for the Basis, or make a selection from the drop-down list. Rate Units Enter the appropriate units for the rate of reaction, or make a selection from the drop-down list. Parameters On the Parameters tab, you may specify the forward and reverse parameters for the Arrhenius equations. These parameters are used in the calculation of the forward and reverse reaction constants. 304 v Reactions The reaction rate constants are a function of temperature according to the following extended form of the Arrhenius equation: { }*T k ′ = A ′ * exp{− }*T k = A * exp − E (RT ) E′ (RT ) β β′ where: k = forward reaction rate constant k' = reverse reaction rate constant A = forward reaction Frequency Factor A' = reverse reaction Frequency Factor E = forward reaction Activation Energy E' = reverse reaction Activation Energy ß = forward extended reaction rate constant ß' = reverse extended reaction rate constant R = Ideal Gas Constant (value and units dependent on the units chosen for Molar Enthalpy and Temperature) T = Absolute Temperature A, E, ß are the Arrhenius Parameters for the forward reaction. A', E' and ß' are the Arrhenius Parameters for the reverse reaction. Information for the reverse reaction isn't required. If the Arrhenius coefficient, A is equal to zero, there is no reaction. If Arrhenius coefficients E and ß are zero, the rate constant is considered to be fixed at a value of A for all temperatures. It is possible to have a gas solid reaction where the rate is purely a function of the gas concentration alone. The reaction rate is then automatically set to zero if the amount of solid is zero, but until that point the rate may be very high. Thus the reaction rate can suddenly drop to zero. This discontinuity makes it hard to solve reactions. Therefore, you can set at what point small component amounts are treated as zero, and also at what point the reaction rate should start to be scaled down to zero. v 305 Chapter 4: Simulation Basis Environment Heterogeneous Catalytic Reaction Petro-SIM provides a Heterogeneous Catalytic Reaction kinetics model to describe the rate of catalytic reactions involving solid catalyst. The rate equation is expressed in the general form according to Yang and Hougen (1950): −r = (kinetic term)(potential term) (adsorption term) Since these types of reactions involve surface reaction together with adsorption (and desorption) of reactants and products, the resulting rate expression will be strongly mechanism dependent. The Heterogeneous Catalytic Reaction view is made up of these tabs: l l l l Stoichiometry Basis Numerator Denominator Consider the following the simple reaction: aA + bB ⇒ cP Depending on the reaction mechanism, its reaction rate expression (ignoring reverse rate of reaction) could be: Langmuir- Hinshelwood Model Eley-Rideal Model Mars-van Krevelen Model r= k + K AK BCAC B (1 + K ACA + K BC B + K P C P )2 r= k + K BCAC B (1 + K BC B + K P C P ) r= k CA 1 + (a / b )(k / k *)CAC B−n where: K = the adsorption rate constant for component * * k = the forward reaction rate constant + k = reaction rate constant for oxidation of hydrocarbon k* = reaction rate constant for surface re-oxidation Petro-SIM has provided a general form, as follows, to let you build in the form of rate expression you want to use. 306 v Reactions Reactants Π C −k Π C kf r= roducts i =1 ai i r j =1 βj j M    M   y kg    1 + ∑ Kk C g    k =1 g =1      Π where: k and k are the Rate Constants of the forward and reverse kinetic rate expressions. f r K is the absorption rate constant M is number of absorbed reactants and products plus absorbed inert species. The rate constants k , k and Kk are all in Arrhenius form. You are required to prove the f r Arrhenius parameters (pre-exponential factor A and activation energy E) for each of these constants. You may have to group constants, for example in Langmuir- Hinshelwood Model equation, k = k K K You must take care in entering the correct f + A B. values of the Arrhenius equation. Also note that no default values are given for these constants. The Heterogeneous Catalytic Reaction option can be used in both CSTR and PFR reactor unit operations. A typical Reaction Set may include multiple instances of the Heterogeneous Catalytic Reaction. Stoichiometry When the Heterogeneous Catalytic Reaction is selected, the following view is displayed: v 307 Chapter 4: Simulation Basis Environment For each catalytic reaction, you must supply the following information: Input Required Description Reaction Name A default name is provided, which may be changed. Components Specify a minimum of one reactant and one product for each reaction you include. Open the drop-down list in the cell to access all of the available components. The Molecular Weight of each component is automatically displayed. Stoichiometric Coefficient Necessary for every component in this reaction. The Stoichiometric Coefficient is negative for a reactant and positive for a product. The Stoichiometric Coefficient need not be an integer; fractional coefficients are acceptable. You may specify the coefficient for an inert component as zero, which in this case is the same as not including the component in the list. Basis The Basis tab for a Heterogeneous Catalytic Reaction is shown in the figure below: On the Basis tab, the following parameters may be specified: Input Required Description Basis Open the drop-down list in the cell to select the Basis for the reaction. For example, select Partial Pressure or Molar Concentration as the basis. Base Component Only a component that is consumed in the reaction (a reactant) may be specified as the Base Component (i.e. a reaction product or an inert component is not a valid choice). You can use the same component as the Base Component for a number of reactions and it is acceptable for the Base Component of one reaction 308 v Reactions Input Required Description to be a product of another reaction. Reaction Phase The phase for which the kinetics apply. Different kinetics for different phases can be modelled in the same reactor. Possible choices for the Reaction Phase, available in the drop-down list, are Overall, Vapour Phase, Liquid Phase, Aqueous Phase and Combined Liquid. Minimum Enter the minimum and maximum temperatures for which the forward and Temperature and reverse reaction Arrhenius equations are valid. If the temperature doesn't remain Maximum in these bounds, a warning message alerts you during the simulation. Temperature Basis Units Enter the appropriate units for the Basis, or make a selection from the drop-down list. Rate Units Enter the appropriate units for the rate of reaction, or make a selection from the drop-down list. Numerator The Numerator tab is specified in much the same way as you would specify a typical PetroSIM Kinetic Reaction. Supply the forward and reverse parameters of the extended Arrhenius equation. The forward and reverse reaction rate constants are calculated from these values. In addition to the rate constants, you must also specify the reaction order of the various components for both the forward and reverse reactions. This is done by selecting the Components field of the Reaction Order cell matrix and selecting the appropriate component from the drop-down list and entering values for the Forward and/or Reverse orders. v 309 Chapter 4: Simulation Basis Environment When specifying Forward and Reverse relationships it's important to maintain thermodynamic consistency. For more information on thermodynamic consistency see the section Kinetic Reaction, Thermodynamic Consistency. Denominator The Denominator tab for a catalytic reaction is shown in the following figure: The Denominator tab contains the Component Exponents matrix in which each row represents a denominator term. The A and E columns are for the pre-exponential factor and the activation energy, respectively for the adsorption term (K). M   M    γk  C g  1 + ∑ Kk =1 g   k =1    Π The remaining columns are used to specify the exponents (γ ) of the absorbed components (C ). kg g To add a term to the denominator of the kinetic expression, activate the row of the matrix containing the <empty> message and add the relevant equation parameter values. The Delete Term button is provided on the right side of the view to delete the selected row (or corresponding term) in the matrix. The overall exponent term n is specified in the Denominator Exponent field. Simple Rate Reaction The Simple Rate Reaction is also similar to the Kinetic Reaction, except that the reverse reaction rate expression is derived from equilibrium data. The Simple Rate Reaction view is made up of these tabs: 310 v Reactions l l l Stoichiometry Basis Parameters Stoichiometry When the Simple Rate Reaction is selected the following view is displayed. After you supply all the required information for the Simple Rate Reaction, the status message changes from Not Ready to Ready. For each reaction, supply the following information: Field Description Reaction Name A default name is provided, which may be changed. Components Specify a minimum of one reactant and one product for each reaction you include. Open the drop-down list in the cell to access all of the available components. The Molecular Weight of each component is automatically displayed. Stoichiometric Coefficient Necessary for every component in this reaction. The Stoichiometric Coefficient is negative for a reactant and positive for a product. The Stoichiometric Coefficient need not be an integer; fractional coefficients are acceptable. You may specify the coefficient for an inert component as zero, which in this case is the same as not including the component in the list. Basis The Basis tab for a simple rate reaction is shown in the following figure: v 311 Chapter 4: Simulation Basis Environment On the Basis tab, the following parameters may be specified: Parameter Description Basis Open the drop-down list in the cell to select the Basis for the reaction. For example, select Partial Pressure or Molar Concentration as the basis. Base Component Only a component consumed in the reaction (a reactant) may be specified as the Base Component (i.e. a reaction product or an inert component is not a valid choice). You can use the same component as the Base Component for a number of reactions and it's acceptable for the Base Component of 1 reaction to be a product of another reaction. Reaction Phase The phase for which the kinetics apply. Different kinetics for different phases can be modelled in the same reactor. Possible choices for the Reaction Phase, available in the drop-down list, are Overall, Vapour Phase, Liquid Phase, Aqueous Phase and Combined Liquid. Minimum Enter the minimum and maximum temperatures for which the forward and Temperature and reverse reaction Arrhenius equations are valid. If the temperature does not Maximum remain in these bounds, a warning message alerts you during the simulation. Temperature Basis Units Enter the appropriate units for the Basis, or make a selection from the drop-down list. Rate Units Enter the appropriate units for the rate of reaction, or make a selection from the drop-down list. Parameters The Parameters tab for a simple rate reaction is shown in the following figure: 312 v Reactions The forward reaction rate constants are a function of temperature according to the following extended form of the Arrhenius equation: E k = A * exp−  * T β  RT  where: k = forward reaction rate constant A = forward reaction Frequency Factor E = forward reaction Activation Energy ß = forward extended reaction rate constant R = Ideal Gas Constant T = Absolute Temperature If Arrhenius coefficient A is equal to zero, there is no reaction. If Arrhenius coefficients E and ß are equal to zero, the rate constant is considered to be fixed at a value of A for all temperatures. The reverse equilibrium constant K' is considered to be a function of temperature only: ln K ′ = A ′ ( )+ D′T B′ + C ′ ln T T where: A', B', C' and D' are constants. You must supply at least one of the four reverse equilibrium constants. v 313 Chapter 4: Simulation Basis Environment Reaction Sets All Reaction Sets created within the Reaction Manager become available for attachment to your reactor operations in the flowsheet. Reaction Sets may contain more than 1 reaction. There's limited flexibility for the mixing of reaction types within a Reaction Set. You can have Equilibrium and Kinetic reactions within a single Reaction Set, but you must have a distinct Reaction Set for conversion reactions. Petro-SIM provides the Global Rxn Set, which contains all compatible reactions that you defined in the case. If you only add Kinetic and Equilibrium reactions, or exclusively Conversion reactions to the case, all reactions are active within the Global Rxn Set. If you add an incompatible mix of reactions (i.e. Conversion and Kinetic), only the type of reactions that are compatible with the first installed reaction are active in the Global Rxn Set. If only 1 type of reaction is used, all reactions are active in the Global Rxn Set, thereby eliminating the need to explicitly define a new Reaction Set. The same reaction can be active in multiple reaction sets. A new set can be added from the Reaction Manager by selecting the Add Set button. Manipulating Reaction Sets All Reaction Set manipulations are conducted in the Reaction Sets group box of the Reactions tab of the Basis Manager. Buttons are available in the Reaction Sets group to manipulate reaction sets: 314 v Button Description View Set Displays the property view for the highlighted reaction set. Add Set Adds a reaction set to the list of reaction sets and opens its property view. Delete Set Removes the highlighted reaction set(s) from the Reaction Manager. You must Reactions Button Description confirm your action to delete a reaction set. Copy Set Duplicates the highlighted reaction set(s). Import Set Opens a reaction set from disk into the current case. Export Set Saves a reaction set to disk for use in another case. Add to FP Accesses the Add Reaction Set Name view, from which you attach the highlighted reaction set(s) to a fluid package. This button is available only when a Reaction Set is highlighted in the Reaction Sets group. When you object inspect a Reaction Set in the Reaction Sets group, you can select View or Delete from the menu. Reaction Set View When you add a new set, or view an existing set, the Reaction Set view is displayed. The following table describes the features contained within this view. Feature Description Name A default Reaction Set name is provided, which may be changed. Set Type Petro-SIM determines the Set Type from the reaction types in the Active List. This field cannot be modified. The Reaction Set types are Conversion, Kinetic, Equilibrium and Mixed. A Mixed Set Type corresponds to a Reaction Set containing both Kinetic and Equilibrium reactions. v 315 Chapter 4: Simulation Basis Environment Feature Description Solver Method The Solver method is available when dealing with Kinetic reaction sets. Several Solver Methods are available from the drop-down list: l l l l l l Active List Default. The Reaction Solver attempts to calculate the solution using Newton's Method. If this is not successful, it then uses the Rate Iterated and Improved Rate Integrated Methods. For most cases, it is best to use the Default Solver Method. Newton's Method. This method usually converges quickly by taking the derivative of the function using the current estimates and uses these results to obtain new estimates. Rate Iterated. This method is a partial Newton's method, and assumes that the off-diagonal elements of the Jacobian matrix are equal to zero. The Rate Iterated Method works well when there is very little interaction between reactions. Improved Rate Integrated. This method integrates the reaction equations until all time derivatives are zero. It uses a variable-coefficient order differential equation solver that can handle stiff and nonstiff systems. It may be slightly slower than other options for moderate well behaved reactions, but solve faster or more reliably otherwise. Rate Integrated. This method integrates the reaction equations until all time derivatives are zero. The Rate Integrated method is stable, but slow. Auto Selected. Same as Default. Reactions may be added to the Active List by positioning the cursor in the Active List column and selecting an existing Reaction from the drop-down list. You may also type the name of an existing reaction directly in the cell that shows <empty>. You can open the property view for any reaction in the Active List by highlighting it and pressing the View Active button. Alternatively, you may double-click on the reaction to view it. A reaction in the Active List may be transferred to the Inactive List simply by selecting the reaction and clicking the Make Inactive button. Inactive List Existing reactions may be added to the Inactive List by positioning the cursor in the Inactive List column and selecting a Reaction from the drop-down list. You can access the property view for any reaction in the Inactive List by highlighting it and clicking the View Inactive button. You may also double-click on the reaction to view it. A reaction in the Inactive List may be transferred to the Active List by selecting the reaction and clicking the Make Active button. If this reaction isn't 316 v Reactions Feature Description independent of other reactions in the Active List, an error message is displayed and the reaction remains in the Inactive List. You cannot have 2 versions of the same reaction with different rate constants in the Active List. Operations Attached All operations to which the Reaction Set is attached are listed in this column. Advanced Features By clicking the Advanced button, you can view the Advanced reaction options. Within the Volume Continuation Parameters group, the following options are available: Object Description Volume Continuation For most cases, it is not necessary to select this option. In situations where convergence is not easily attained (e.g. - high reaction rates), check the Volume Continuation box to enable Petro-SIM to more easily reach a solution. For Volume Continuation calculations, Petro-SIM "ramps" the volume starting from the initial volume fraction to the final volume fraction in the specified number of steps. For each successive step, the previous solution is used as the initial estimate for the next step. Initial Volume The default value is 1.0000e-06. This is the Volume Fraction at the start of the v 317 Chapter 4: Simulation Basis Environment Object Description Fraction calculations. Number of Steps The default value is 10. If the solution does not converge, increase this value and re-run the simulation. Current Parm Value This field displays the current parameter value. Current Step Number This field displays the current step number. Trace Level Provides a trace output of the calculations in the Trace Window. The trace level value corresponds to the level of detail that you see in the Trace Window. You are limited to the values 0, 1, 2 or 3. Prev Solution as Estimates It is necessary to make an initial estimate of the outlet compositions to obtain the proper solution. Check this box if you want to use the previous solution as the initial estimate. This does not apply to the conversion reaction, since the specified conversion determines the outlet compositions. Use Iso and Adia If you calculate a heat flow given a specific temperature, and then use this heat Temp as Adia Est flow as a spec (deleting the temperature specification), Petro-SIM uses the previously calculated temperature as an estimate for the Adiabatic calculation. The parameters within the Initial Estimate Generation Parameters group are generally used with Reactions that have a high degree of interaction. You can also use these parameters to give some assistance in obtaining the final solution when the reactor operation fails to converge or when you have a large number of components and reactions. The parameters are described in the following table: 318 v Parameter Description Damping Factor Default is 1.0, indicating that there is no damping. You can change this value. With a lower the damping factor, Petro-SIM uses smaller steps (slower and more stable) in converging towards the solution. Tolerance This is the tolerance set for the Estimate Generation. By default, this is set to 0.001. You are able to change this value. Maximum Iterations Maximum number of iterations Petro-SIM uses. There is no default value, and so you can set whatever value is desired. Reactions The Reaction Solver Option group lets you set the number of iterations and the tolerance level. The option depends on the boundary condition of the reactor operation that is using the reaction set. For example, when a reactor operation is used to determine the outlet temperature, the number of iterations and tolerance level are used in the reaction solver to search for a solution. Option Description Max Numb of Iterations Controls the maximum number of iterations specified before the reaction solver stops searching for a solution. By default, the value is 200. Tolerance The specified tolerance level is the relative error between the energy balance equation and the calculated value by the reaction solver in the iteration. By default, the value is 0.00001. Reaction Rank The Ranking button is visible only when the Reaction Set type is Conversion. This option automatically handles most situations where reactions are sequential: Allowing the 3 reactions to be modelled in a single reactor. In this case the Rank would be: A ⇒ B would be Rank 1 B ⇒ C would be Rank 2 C ⇒ D would be Rank 3 In situations where there are competing reactions such as the following: Rxn-4 Rxn-5 A+B⇒C B+D⇒E You can use the Ranking factor to specify which conversion value should be applied first. For example, if Rxn-4 was ranked first, the specified conversion for Rxn-5 would only be applied to the amount of component B remaining after Rxn-4 had run to its specified conversion. To specify the Ranking, you must do so from the Reaction Ranks view: v 319 Chapter 4: Simulation Basis Environment Petro-SIM assigns default ranks to multiple conversion reactions by examining the reactants and products. For example, you may have a reaction set containing the following: CH 4 + H 2O ⇔ CO + 3H 2 CH 4 + 2H 2O ⇔ CO 2 + 4H 2 CH 4 + 2O 2 ⇔ CO 2 + 2H 2O Petro-SIM notices that a product of Reaction 3, H O, is used as a reactant in both Reactions 1 and 2 2. Since H O may not be available until Reaction 3 has occurred, it is assigned a rank of 0and the 2 other reactions are each given the default Rank of 1. The feed composition is not taken into account, as Reaction Ranks are assigned before entering the Build Environment. Object Description Reaction This column shows all of the reactions to be ranked. Rank Shows the rank for each reaction, which is an integer value. The minimum value is zero and the maximum is equal to the number of Reactions ranked. Thus, when ranking three sequential reactions, you may rank them 0-1-2 or 1-2-3; both methods give the same results. You may also set two or more reactions to have the same Rank; for instance, the ranks for Rxn-1 and Rxn-2 may be 1, and the rank for Rxn-3 may be 2. You may override the default values through the input of new values in the appropriate cells. User Specified If you specify the Rank of the reaction, this box is checked. The buttons along the bottom of the Reaction Ranks view are: 320 v Button Description Cancel Closes the view without accepting any changes that were made. Reset Resets the Reaction Ranks to the internal default. Accept Closes the view, accepting the changes that were made. Reactions Exporting/Importing a Reaction Set After a Reaction Set is customized with reactions, it can be exported to a file. The same Reaction Set can then be used in another simulation case by importing the file and attaching it to a fluid package. Highlight a Reaction Set in the Reaction Sets group of the Reaction Manager and click the Export Set button. Select a file path (the default is usually satisfactory) and a filename with the extension .*rst. Click the Save button to export the reaction set to a file. The Import Set button lets you introduce an exported Reaction Set into a simulation case. Choose the Reaction Set file (with the extension *.rst) from the list and select the Open button. If the file isn't listed in the File Name box, an alternate File Path may be needed. Adding a Reaction Set to a Fluid Package To make a Reaction Set available inside the flowsheet, you must attach it to the fluid package that is associated with the flowsheet. Highlight a reaction set in the Reaction Sets group of the Reaction Manager and click the Add to FP button. The Add Reaction Set Name view appears, where you can highlight a fluid package and click the Add Set to Fluid Package button. v 321 Chapter 4: Simulation Basis Environment Reactions in the Build Environment When you're inside the Main or Column Environment you can access the Reaction Package view without having to return to the fluid package. Under Flowsheet in the Main Menu, select Reaction Package. Refer to Unit Operations for more information on the individual unit operations. When a Reaction Set is attached to a unit operation, you can access the Reaction Set view or the view(s) for the associated Reaction(s) directly from the property view of the operation. Some of the unit operations that support reactions include the Reactor operation (conversion, equilibrium, or kinetic), the PFR, the Separator and the Column. Refer to Reaction Package for more details. Generalized Procedure The following procedure outlines the basic steps for creating a reaction, creating a reaction set, adding the reaction to the reaction set and then making the set available to the flowsheet. Refer to the Reaction Package view as you follow the procedure: 1. Select Reaction Package under Flowsheet in the menu bar. 2. On the Reaction Package view, click the Add Rxn button to create a new Reaction. A Reactions view displays, from which you must select the type of reaction to create. 3. Select a reaction type and click the Add Reaction button. 4. The property view for the reaction type you selected is displayed. 5. Complete the input for the reaction until Ready appears as the status message. You can close the Reaction property view, if desired. 322 v Reactions 6. On the Reaction Package view, click the Add Set button to create a Reaction Set. The Reaction Set view appears. 7. If desired, change the Name of the Reaction Set to better identify it. 8. To attach the newly created reaction to the Reaction Set, place the cursor in the <empty> cell of the Active List column. Open the dropdown list in the cell and select a reaction. The reaction becomes attached to the Reaction Set, as indicated by the activated check box in the OK column. 9. Click the Close button on the Reaction Set view. 10. In the Available Reaction Sets group of the Reaction Package view, highlight the name of the newly created Reaction Set. Notice that the attached reaction is listed in the Associated Reactions group. 11. Click the Add Set button to make the Reaction Set and thus the Reaction, available to unit operations in the flowsheet. The new Reaction Set is displayed in the Current Reaction Sets group. Reactions Tutorial The following procedure demonstrates the minimum steps required for: Step 1: Add Components to the Reaction Manager For this example, it's assumed that a New Case is created and a fluid package is installed. Also, within the fluid package, the Peng Robinson property package is selected and the following set of components are selected: H O, CO, CO , H , O and Methane. 2 2 2 2 Go to the Reactions tab of the Simulation Basis Manager. The selected components are present in the Rxn Components group. Refer to Petro-SIM Fluid Package Property View for details on installing a fluid package. v 323 Chapter 4: Simulation Basis Environment Step 2: Create a Reaction 1. Click the Add Rxn button. 2. From the Reactions view, highlight the Conversion reaction type and click the Add Reaction button. The Conversion Reaction property view appears. 3. On the Stoichiometry tab, select the first row of the Component column in the Stoichiometry Info table 4. Select Methane from the drop-down list. The Mole Weight column automatically provides the molar weight of methane. 5. In the Stoich Coeff field, enter -3 (i.e., 3 moles of methane is consumed). 6. Now define the rest of the Stoichiometry tab and click the Balance button. 7. Go to the Basis tab and set Methane as the Base Component and Conversion to 60%. The status bar at the bottom of the property view now shows a Ready status. Close the property view. Step 3: Add the Reaction to a Reaction Set By default, the Global Rxn Set is present in the Reaction Sets group when you first display the Reaction Manager. For this procedure, a new Reaction Set is created: 1. Click the Add Set button. Petro-SIM provides the name Set-1 and opens the Reaction Set property view. 2. To attach the newly created Reaction to the Reaction SeT, Place the cursor in the <empty> cell under Active List and open the drop-down list. 3. Select the name of the Reaction (Rxn1). The Set Type corresponds to the type of Reaction that you've added to the Reaction Set. The status is now Ready. 324 v Component Maps 4. Close the view to return to the Reaction Manager. Step 4: Attach the Reaction Set to a Fluid Package 1. Highlight Set-1 in the Reaction Sets group. 2. Click the Add to FP button. When a Reaction Set is attached to a Fluid Package, it becomes available to unit operations within the Flowsheet using that particular Fluid Package. The Add 'Set-1' view appears, from which you highlight a fluid package. 3. Click the Add Set to Fluid Package button. Component Maps The Component Maps tab of the Simulation Basis Manager is used to map fluid component composition across fluid package boundaries. Composition values for individual components from one fluid package can be mapped to a different component in an alternate fluid package. This is usually done when dealing with hypothetical oil components. v 325 Chapter 4: Simulation Basis Environment Two previously defined fluid packages are required to perform a component mapping which is defined as a collection. One fluid package becomes the target component set and the other becomes the source component set. Mapping is performed using a matrix of source and target components. The transfer basis can be performed on a mole, mass or liquid volume basis. Component Mapping The Component Mapping group defines the source and target fluid packages to be mapped. Once two distinct fluid packages are selected, click Create Collection to create a collection in the Collections group. Collections The Collections group lists the component mapping collections available. You can change the collection name by selecting the name you want to edit and typing in the new name. Maps for Collections The Maps for Collections group lets you manage your Component Maps for each collection. From the Collection drop-down, select the collection maps that you want to add, edit or delete. A default collection map is added to this list and cannot be deleted. To add a Component Map based on the currently selected collection, click Add. To view a Component Map, select it from the list and click View. Either option opens the Component Map property view where you can view,modify, or clone the components. To delete a Component Map, select the map from the list and click the Delete button. 326 v Component Maps Component Map Property View Each time a Component Map is created or viewed using the Component Maps tab of the Simulation Basis Manager, the Component Map property view opens The Component Map Property view lets you map the source components to the target components in the component matrix. Within the matrix, you can map all Specifiable (in red) component mapping values. The options found in this view are: Object Description Name Displays the name of the component map. The name can be modified. View options Choose how you want to view the component matrix: View All. Display all source and target components in the matrix. View Specifiable. Display only the components that require values. Transpose. Transpose the component matrix. Component transfer options Choose one of these transfer options. Unlock all Components. Unlock all component values, so you can specify your own values. Transfer Like Hypotheticals. Automatically map similar hypotheticals. In addition, check one or both of these additional features: l l Transfer Hypos by NBP. Automatically map source hypos to target hypos with the nearest NBP. Distribute Across Hypos. Determine the boiling range of source hypo v 327 Chapter 4: Simulation Basis Environment Object Description and maps across all target hypos that fall in the same range. Transfer basis Choose the option to define the composition mapping basis: l l l Mole Mass Liq Volume Multiple Specify If components are unlocked, select one or more component cells (use the CTRL or SHIFT key to select 2 or more cells), enter a value in the Specifiy field, and then click Specify to apply the value to the selected cells.. Assay Transfer Options Check the options that you want enabled: Transfer Assays. To transfer assay properties across. The property values in each property vector are mapped in accordance with the component map coefficients. l l Re-Cut Properties. Source property vectors are mapped to an intermediate fixed component slate, and the fixed slate properties are then mapped to the target property vectors. This option is recommended only when preserving the results of older cases. Re-Cut Composition. Composition is transferred using the same method as Re-Cut Properties; the component map is not used. Clone from another Map Import values into the mapping matrix from another map. Clear All Remove all of the user defined information from the matrix. Normalize Normalize the mapping matrix. User Properties On the User Properties tab of the Simulation Basis Manager, you can create an unlimited number of user properties for use in the build environment. A User Property is any property that can be defined and subsequently calculated on the basis of composition. When user properties are specified, they are used globally throughout the case. You can supply a User Property value for each component. User properties can be modified for a specific component, fluid package, or stream using the property editor. 328 v User Properties Specifying a User Property is similar to supplying a value at the component level in that it is globally available throughout the case, unless it is specified otherwise. It is the initial user property value for the component in the master component list. By selecting the mixing basis and mixing equation, the total user property can be calculated. After a user property is defined, Petro-SIM is able to calculate the value of the property for any flowsheet stream through the User Property utility. User Properties can also be set as Column specifications. Click... To... View Modify the selected user property. Refer to Adding a User Property. Add Create a new user property. Delete Delete a selected user property. Petro-SIM does not prompt for confirmation when deleting a user property. The User Property Parameters group displays all information pertaining to a selected property in the User Properties list. A user property can also be added or viewed from the Oil Characterization Environment, User Property tab. Adding a User Property 1. On the User Property tab of the Simulation Basis Manager, click the Add button. 2. On the User Property view, select a Mixing Basis, and then select a Mixing Rule. v 329 Chapter 4: Simulation Basis Environment 3. Optionally, modify the two Mixing Parameters (F1 and F2) to more accurately reflect your property formula. 4. Select a Unit Type from the drop-down list. 5. Enter initial property values for each component. 6. Enter the Refinery Options specific to your synthesis. 7. Optionally, close the User Property view (or move it aside). 8. On Simulation Basis Manager view, in the User Property Parameters group, enter a descriptive Name for the user property. 9. When the user defined assay property is set up, return to the Refinery Assay tab in the Oil Environment to create an assay. User Property View When you create or edit a user property from the User Property tab of the Simulation Basis Manager, the User Property view is displayed. All information regarding the calculation of the User Property is specified on the Data tab. To add comments or notes, refer to Notes. Data The Data tab displays the user property parameters in the following groups: 330 v User Properties Parameter Description Mixing Basis The options are Mole Fraction, Mass Fraction, Liquid Volume Fraction, Mole Flow, Mass Flow, and Liquid Volume Flow. Note that all calculations are performed using compositions in Petro-SIM internal units. If you have specified a flow basis (molar, mass or liquid volume flow), Petro-SIM uses the composition as calculated in internal units for that basis. For example, a User Property with a Mixing Basis specified as molar flow is always calculated using compositions in kg mole/s, regardless of what the current default units are. Mixing Rule Select from one of three mixing rules: N ( ) ( ) (Pmix)f 1 = f 2 ∑ x(i)P(i)f 1 i =1 f1 N (Pmix) = f 2 ∑ x(i)ln(i)f 1 i =1 v 331 Chapter 4: Simulation Basis Environment Parameter Description N Index = f 2 ∑ x(i) f 1 * P(i) + 10f 2P(i )  i = 1 ( )) where: P = total user property value mix P(i) = input property value for component x(i) = component fraction or flow, depending on the chosen Mixing Basis Index = blended (total) index value f1 and f2 are specified constants There are three mixing rules available when you are defining a user property. Equations for mixing mule 1 and 2 are relatively straightforward. The index mixing rule,mixing mule 3, is slightly more complex. With the index mixing rule, Petro-SIM lets you combine properties that are not inherently linear. A property is made linear through the use of the index equation. The form of the index equation must resemble the Petro-SIM index equation such that you can supply the f1 and f2 parameters. Some common properties that can use the Index equation include RON, Pour Point and Viscosity. Equation can be simplified into: Indexi = f 1 * P(i) + 10f 2 * P(i ) N Index= ∑ x(i) * Indexi i =1 Index = f 1 * P + 10f 2 * P You supply the individual component properties P(i) and the index equation parameters (i.e., f1 and f2). Using Index equation 1, Petro-SIM calculates an individual index value for each supplied property value. The sum of the index values, which is the blended index value, is then calculated using the Mixing Basis you have selected Index equation 2. The blended index value is used in an iterative calculation to produce the blended property value (P in Index equation 3). The blended property value is 332 v User Properties Parameter Description the value that will be displayed in the user property utility. Mixing Parameters The mixing parameters f1 and f2 are 1.00 by default. You may supply any value for these parameters. Unit Type This option lets you select the variable type for the user property. For example, if you have a temperature user property, select temperature in the unit type using the drop-down list. Refinery Options The Refinery Options group is included to define user defined assay properties for refinery. The assay synthesis requests and uses these options for generating the data for each component for the assay property. Synthesis takes property values of one or more wide cut streams and distributes the property values between components using a curve fitting technique. If the assay is generated from a single plant data stream, the distribution of the property over the components can either consist of the same value for every component or distributed on the basis of the supplied curve shape (polynomial equation). The curve position is adjusted so that the calculated stream value is close to the specified measured value. For more information, refer to Synthesizing a Refinery Assay. The options available for refinery type properties are: Parameter Description Min/Max warning user prop value These values are used to check input data supplied for the property in synthesis. If you input a user property value that is outside the minimum or maximum warning limits, refinery uses this data, but generates a warning message. By default the fields are <empty>. The Lower and Upper limit Values in the Basic user prop definition are used as extreme limits on input data. The internal unit for temperature variable type is Kelvin. The displayed temperature can change depending on you, but the internal values do not. Therefore the internal unit affects the calculated results. Correlation lower/ A lower and upper temperature limit beyond which property values for upper temp limit components are not synthesized. The temperature limit is different from the warning limits in that they apply to calculated values for streams. By default, the upper and lower limits are 36 °C and 1000 °C, respectively. Property values for components (hypocomponents) whose average boiling points are outside the temperature limits are set to <empty> unless they are pure components, in which case they are user supplied values. If the property value v 333 Chapter 4: Simulation Basis Environment Parameter Description is set to <empty> for any component in a stream, a <empty> value is calculated for the property when a value for the user property is calculated for a stream. This feature is useful in preventing properties such as octane numbers being calculated for vacuum residue streams. Relative tolerance The property value convergence tolerance used to compare input and in synthesis calculated values when synthesizing the property. By default, the value is 0.01, which is a typical starting point. Polynomial Coef- An imposed curve shape on the synthesized property value over the ficients appropriate range of hypocomponent boiling temperatures. The 5th order polynomial takes the form of: Property(T ) − a 0 + a1T + a 2T 2 + a 3T 3 + a4T 4 + a 5T 5 where: Property = User property value (Petro-SIM internal units) T = Hypocomponent boiling temperature (°C) a = Coefficient in the table n The polynomial coefficients are provided as a function of component average boiling point (°C). The basic curve shape is manipulated in the synthesis to match the supplied plant data stream values. A lower than 5th order polynomial may be used, but ensure that the higher coefficients are set to zero. Specifying the polynomial is optional and should be used where you want to override the default curve methods. The internal unit for temperature variable type is Kelvin. The displayed temperature can change depending on you, but the internal values do not. Therefore the internal unit affects the calculated results. Initial user property values for all components in master component list Use this are to define how Petro-SIM should initialize the user property throughout the case. When the value of a user property is requested by the User Property utility or by the Column specification, Petro-SIM uses the composition in the specified basis, and calculates the user property value using your mixing rule and parameters. The values for pure components are always used for the property and are not overwritten by the synthesis. The values for hypocomponents are only used if the synthesis of the property cannot be achieved. For example, if there are insufficient number of data points. 334 v User Properties 1. To specify a Property Value, click Edit component user property values. 2. In the UserProp view, edit the initial user property values for components in the master component list. 3. When you are done entering or modifying the property values, click Submit. The changes are reflected on the User Property view for each component. v 335 Chapter 5: Oil Characterization Environment The Oil Characterization Environment is where you define the petroleum fluids in your simulation by creating and defining assays and blends. The Default Fluid Package drop-down allows you to select the default fluid package for your case. The Oil Characterization Environment is made up of these tabs: l l l l Refinery Assay — create, publish, or import/export refinery assays, and manage their use in your simulation by performing refinery assay syntheses. You can also process a several large assays simultaneously using Bulk Assay Processing. Black Oil — construct a compositional fluid model from limited compositional data for a fluid. SCN Analysis — load SCN Oils into Petro-SIM from exported SCN Oil files (*.xml), or create your own SCN Oil from laboratory data through synthesis using KBC’s Multiflash technology. User Property — define or manage user properties based on component composition. To enter the Oil Characterization Environment, follow one of these procedures: v 337 Chapter 5: Oil Characterization Environment From the Oil Manager From the Simulation Basis Manager, select the Oil Manager tab and then click Enter Oil Environment. Before you can enter the environment from the Oil Manager, you must have at least one Fluid Package defined in the case. From the Home tab From the Home tab, click Oil in the Environment group. Create a new basecase Start Petro-SIM and before loading any case, click Oil on the Home tab. Petro-SIM opens a standard oil basecase which contains the refinery large component list and a component splitter for generating cuts from an assay attached to a feed stream. When you are in the Oil Characterization Environment, the Oil Characterization tab on the ribbon becomes available. Refinery Assays When describing oils generated using oil characterization, the term assay is also used to define the oil. Refinery assays are generated based on KBC’s Refinery Oil Model, which is a conceptual model with an associated collection of software methods for characterizing the measurements and 338 v Refinery Assays properties of hydrocarbon materials. It is based on a matrix that holds properties for the chemical components that make up a material, and it is also based on being able to calculate property values for combinations of those components in the form of streams or substances. In oil characterization, refinery assays are generated through a series of characterization and synthesis techniques. Hypothetical components with varying boiling points and fixed properties are not generated. Instead, a standard hypothetical component list is required for each refinery assay. This component list holds both a standard set of hypocomponents along with any other pure components you may have added. The properties of the hypothetical components vary throughout the flowsheet. The Refinery Assays tab in the Oil Characterization Environment consists of two sections: Available Refinery Assays The Available Refinery Assay area lists the available refinery assays. Use this area to load refinery assays from exported assay files (*.asy) or templates (*.ast), or create your own refinery assay from laboratory data through synthesis. Refinery assays must be available to the refinery assay manager before they can be used in your simulation. Use... To... View Source Display more information about the data source used to create the refinery assay l l Create If the source is a synthesized assay, the Refinery Assay Source (Synthesized) view opens. If the source is a stored stream, the Refinery Assay Source (Stream) view opens displaying the following information. Create a new refinery assay through synthesis. v 339 Chapter 5: Oil Characterization Environment Use... To... Delete Remove a selected refinery assay from the case. Be careful when deleting assays. You are not asked to confirm the deletion. Import Import assays from the following sources: l l l l Export Refinery Assay Files H/CAMS CADB Installation Petro-SIM Database Export refinery assays to the following: l XML File Petro-SIM Database Petro-SIM Database With New Name Refinery Assay as Template l Assay And Fluid Package l l l Clone Create a copy of an assay that is automatically appended with a numbered suffix to the assay name. Check Out This button is available only if you are connected to a database that supports assay version control. Re-load the latest database version and check out the selected assay so that other users cannot make changes to it. Use Publish or Revert to check it back into the database. See Publish Refinery Assays for more information. 340 v Refinery Assays Use... To... Publish This button is available only if you are connected to a database that supports version control. Select: l l l Revert New Assay – to publish selected assays as a new assay objects in a database collection. Optionally, change the name of the assay object in the Export as field. Private Revision – Available only if you have checked out the assay object from the database. Checks in the assay to the database hiding your updates from other users. Others users do not see your updates. Public Revision – Available only if you have checked out the assay object from the database. Checks in the assay to the database making your updates visible to other users. This button is available only if you are connected to a database that supports assay version control. Checks in the assay to the database reverting all intermediate revisions and restoring the assay to its initial state. Refinery Assay Information The Refinery Assay Information area displays detailed information about a selected assay in the Available Refinery Assay area. Use... To open... View Data Matrix Assay Data Matrix view of components vs properties. View Users Users view which shows the flowsheet streams that have been assigned to the selected assay. v 341 Chapter 5: Oil Characterization Environment Use... To open... Refer to Streams, Composition page for more information . View Bulk Variables Displays the Bulk Variables view in which you add or modify user variables that represent values for the selected assay. Refer to Managing User Variables for more information about managing your variables. Refinery Oil Model A refinery assay is the collection of property values for a set of hypothetical (pseudo) components, together with its generated refinery assay matrix. The set of information that makes up an oil model is shown below, with shading used to indicate the extent of the model. 342 v Refinery Assays The Refinery Oil model implemented in Petro-SIM encapsulates the technology for refinery assay synthesis and physical property calculations and the supporting structure to store and retrieve an assay matrix from an external refinery assay file. Refinery Assay Matrix A refinery assay matrix is defined as a collection of information about a hydrocarbon-based material. The matrix holds the basic data needed to drive the refinery physical property system. This system calculates values for several hundred physical, transport and thermodynamic properties from this basic data that is organized as a series of property contribution values for hypocomponents. Plant Data The raw data input to generate the refinery assay matrix is called plant data. This data consists of measurements of the physical properties of parts of the material. For example, a laboratory may take a crude oil, fractionate it into gas, naphtha, kerosene, diesel, and residue fractions, and then measure the important properties of each of those fractions. The process of synthesis combines the properties of each fraction to generate the refinery assay of the whole crude. Synthesis is not restricted only to crude oils. It can be used for parts of crudes (e.g., synthesizing an atmospheric residue from vacuum unit products) for reactor products or any other refinery stream containing hypocomponents. v 343 Chapter 5: Oil Characterization Environment The fractions (or cuts) that, when added together, exactly reconstitute the original material are termed contiguous cuts. Plant data for a refinery assay must consist of data for a complete set of contiguous cuts. A refinery assay can be synthesized from a single contiguous cut. Extra properties may be measured for combinations of contiguous cuts or for new cuts. This data can be used in the synthesis. It adds extra information, and is termed overlapping cut data. You can specify minus streams whose contribution to the overall composition and property curves are subtracted from the resulting synthesis. This is to allow for the situation where you want to synthesize without the contribution of an extraneous stream. For example, a refinery assay is being synthesized from fractionator product data. A wild naphtha stream is also fed to the fractionator and needs to be removed from the product to generate the main feed. The following image shows the plant data that makes up the laboratory data for a residue with four cuts. Update Cuts It is not uncommon for assay data to be partially revised on a regular basis. For example, a cargo of crude may be partially assayed to determine if its gravity and sulfur are within expectations. This partial data can be supplied to synthesis and used to modify the measured properties using update cuts. If for example, a crude arrives and its total SG and sulfur content are different to that measured by the full laboratory assay, the property distribution curves can be modified to reflect the bulk value as follows: 1. Set up a single Update Contiguous cut with cut points to encompass the entire crude assay and give it the required total sulfur content and SG. 344 v Refinery Assays 2. The SG of the assay will first be synthesized in the normal way using data from the Contiguous and Overlapping cuts and then the whole curve will be shifted to match the update value without changing the basic curve shape. 3. Other properties in the assay that are synthesized on a weight basis will then use the revised SG curve so that the assay is still consistent. 4. The whole assay sulfur content will also be revised to reflect the bulk sulfur content supplied without changing the basic curve shape. To update SG values from update cuts, it is necessary to set Update density from Update Cuts to Yes in the Synthesis Parameter view. If there are significant differences between the laboratory assay and the update information, the original cut data for one or more properties can be abandoned in favour of the update information. Physical Properties Some physical properties supported in the Refinery Oil model are maintained directly in the refinery assay and are calculated from a contribution from each hypocomponent. Other properties are derived from those in the matrix; values for a stream are calculated from the stream values of one or more refinery assay properties. Some properties require a qualifier. For example, kinematic viscosity can be measured at a wide range of temperatures. So, to uniquely define the property kinematic viscosity, it must be qualified with the temperature at which it is measured. For example, a fully qualified property might be kinematic viscosity at 50°C (122°F) and this is a different property with a different value to kinematic viscosity at 60°C (140°F). The dimension of a property (or qualifier) indicates the units in which it can be measured or reported. Refer to Refinery Physical Properties for the complete list of supported properties in the Refinery Oil model, the qualifier values, and their dimensions. Calculation Methods Some physical properties have more than one calculation and/or synthesis method. Methods are given names in the user interface that align with the methods described in Synthesis Parameters. Synthesizing a Refinery Assay The Refinery Assay Source (Synthesized) view enables you to create refinery assays by synthesizing either laboratory wide cut data or plant data. Assays generated in this way can be stored for future use. Laboratory wide cuts have wider boiling ranges than those of a single hypocomponent. A function of synthesis is to break the wide cuts down into hypocomponent values (narrow cut values). v 345 Chapter 5: Oil Characterization Environment Refer also to the Refinery Assay Synthesis Tutorial for an example case for synthesizing a refinery assay. 1. To perform a refinery assay synthesis, define the synthesis inputs (Plant Data Groups, Synthesis Property Selections, and Cuts) on this tab: Input Summary tab The Input Summary tab displays the Plant Data Groups that you have set up for the refinery assay. Use these buttons to manage the Plant Data Groups in the refinery assay. Click... To... Add Add a new Plant Data Group and associated refinery cuts. Edit Modify a selected Plant Data Group. You can also double-click a group name in the list to edit it. Clone Make a copy of a selected Plant Data Group and append it to the list. Delete Remove a selected Plant Data Group from the assay. 2. Optionally, modify the synthesis methods and parameters on the Calcualtion Defaults tab. 346 v Refinery Assays Calculation Defaults tab When you set up the Plant Data Groups and cuts that make up the assay, Petro-SIM defines default values for the synthesis and physical property parameters and methods used for the synthesis. You can use the default values or, optionally, modify the values. All default values display in red. If you modify any parameter or method, the value is displayed in blue text. l l l l Synthesis Parameters Synthesis Methods Physical Property Parameters Physical Property Methods Refer to Synthesis Calculation Hierarchy for more information about methods and properties. 3. When you are finished defining the synthesis data, click Synthesize on the Refinery Assay Source (Synthesized) view. v 347 Chapter 5: Oil Characterization Environment For a successful synthesis, the status bar displays: Synthesis Succeeded in green. 4. View the Synthesis Diagnostics tab for more details about the synthesis. Synthesis Diagnostics tab The Synthesis Diagnostics tab displays detailed results of the synthesis. If errors are generated during the synthesis the status bar display Synthesis Failed in red. Errors must be resolved before an assay can be successfully re-synthesized. 348 v Refinery Assays 5. To print the synthesis diagnostics results, right-click the Synthesis Diagnostics tab's background and select Print Text. 6. If the synthesis is not successful, examine the Synthesis Messages tab to view the warnings or errors generated. Synthesis Messages tab The Synthesis Messages tab displays the warnings or errors that occurred during the synthesis. The Available Messages list displays orders all generated messages from the most to least significant. Select a message to display information about the message in the Message Text group. The Details of Selected Message group displays the following details: Object Description Type Displays the message type: l l Warning - do not cause the synthesis to fail Error - cause the synthesis to fail. Severity Severity numbers range from 1 to 10, with 6 or over defined as Errors and 5 or less defined as Warnings. Class A number code for the type of problem. Class Serial No. Displays the serial number of the class. Synthesis messages that have the same serial number represent v 349 Chapter 5: Oil Characterization Environment Object Description messages that are similar in content. For example, the serial number is the same for each message that warns you about a composition stream that does not sum to 100% and is normalized. Message Text Detailed description of the error or warning. 7. Correct any errors and perform the synthesis again until all errors are resolved. Plant Data Groups The Plant Data Group view displays the refinery cuts and properties. Use these buttons to create and manage the refinery cuts. Click... To... Setup Open the Synthesis Property Selection view to add refinery properties to the Plant Data Properties Group. Append Cut Open the Cut view to define and append a new cut to the Plant Data Group. Insert Cut Open the Cut view to define and insert a new cut before a selected cut in the Plant Data Group. Edit Cut Open the Cut view to modify a selected cut. Clone Cut Makes a copy of a selected cut and appends it to the Plant Data Group. Delete Cut 350 v Remove a selected cut from the Plant Data Group. A dialog box asks to confirm the deletion. Refinery Assays Check: l l Show Calc Values to add a column per cut that shows back calculated values for the entered properties once synthesis is complete. Show blank as empty value to make all empty cells display nothing rather than <empty>. After you add a new refinery cut, define its properties in the grid. Refer to Cut View for details on the minimum data required. To perform the refinery assay synthesis, see Synthesizing a Refinery Assay. Synthesis Property Selection Click Setup Properties in the Plant Data Group to add refinery properties to the group. Properties may only be added once to each Plant Data Group. The Available Properties list shows all available refinery property values for selection. To add a property, select it from the Available Properties list, and then click Add. The property is move to the Selected Properties group. You can move only one property at a time. If a refinery property needs a qualifier, the Cut Property view (see examples below) automatically opens where you can define qualifiers before adding the property. Check the qualifiers or enter input qualifiers (for example, a range of values for vol % to define the distillation TBP curve) when required. v 351 Chapter 5: Oil Characterization Environment Qualifiers are required for the following properties: l l l l l l l Component composition Density Distillation properties Evaporation properties Motor/research octane number Refractive index Viscosity (dynamic/kinematic) Each refinery property added displays as a row in the Plant Data Group view. Once you have finished adding and defining all necessary properties and cuts to your Plant Data Group, the status bar should read: Plant Group Ready in green. 352 v Refinery Assays Cut View The Plant Data Group is made up of refinery cuts. You can append, inset or edit cuts using this view. Define the cut details and then click OK. Use... To... Cut Name Enter a unique name for the cut. Cut Type Select the cut type: l l l Contiguous – Synthesis assumes that the set of contiguous cuts make up the original material. They can slightly overlap with other contiguous cuts. This is the default. Overlapping – This cut’s boiling range overlaps the contiguous set completely and provides supplementary information. Minus – Subtract this cut from the set of contiguous data. Often used in v 353 Chapter 5: Oil Characterization Environment Use... To... l l l l l synthesizing column feeds where you want to subtract the effect of secondary feeds such as gas streams and wild naphtha feeds. Naphtha Components – This cut contains naphtha component data deriving from GC analysis. Information will typically overlap a distillate contiguous cut. Update Contiguous – An update cut containing contiguous stream data. Update Overlapping – An update cut containing overlapping stream data. Update Naphtha – An update cut containing naphtha component data. Exclude – Exclude this cut from synthesis. Cut Status Displays the current status for the cut. Define the cut's properties in the Plant Data Group view. If all properties are defined, the status indicates that it is ready to use. Input/Calc Shows you whether the column contains input data or calculated values Complete the following required information for the cut in the Plant Data Group view. Data for one or more properties of one or more contiguous cuts must be supplied. A cut cannot be synthesized unless these rules are met. The minimum data required for a cut is defined below. l l At least one of: o Mass flow o Molar flow o Volume flow o Gas vol flow o Mass percent yield o Volume percent yield At least one of: o o l Complete component composition Density at any temperature or SG or API gravity Distillation (5,10,30 and 50 are the required points) or both initial and final cut points. If you specify distillation for one cut, then you must specify distillation for all cuts, except for cuts specified by a composition, which can be mixed with either type of stream specified by distillation or cut points. If the cut is a residue stream, the distillation may be omitted. Synthesis Calculation Hierarchy You can modify methods or parameters for a particular assay, unit operation, or stream property calculation. Each method provides alternate calculation options that may be selected for a 354 v Refinery Assays synthesis. The goal should be to use the same methods throughout your case or cases to improve the consistency of results. When performing the synthesis, Petro-SIM starts from a set of System Defaults that are overridden by the selections you make at these stages Oil Synthesis Preferences Your preferences can change the system defaults, becoming the values used in any Petro-SIM session. They apply to any new case you create. Existing cases by default retain the methods saved with that case. You can select a different Recall Option to have your preferences applied to update the case settings. (We recommend you use this option sparingly). Oil Synthesis default settings are viewed and edited in your Preferences, Oil Synthesis tab. Case Oil Synthesis Settings The case oil synthesis settings apply throughout your simulation case unless overridden on an object by object basis. Some objects such as Refinery Reactors apply their own defaults to some synthesis methods and parameters. Case Oil Synthesis Settings are viewed and edited by selecting Oil Synthesis on the ribbon's View tab. . Individual Object Settings Changes you make within an object represent the highest level of the hierarchy, overriding any case setting for that object. Refinery assay settings are found on the Refinery Assay Source, Calculation Defaults tab (described below). Individual reactors and refinery unit operations settings can be viewed by right-clicking the unit operation's property view, and then choosing Synthesis Settings. v 355 Chapter 5: Oil Characterization Environment The order of the parameters you see in each view may be different. Right-click the grid and select Sort, Sort by left labels. Refer also to Standard Methods and Calculations for descriptions of refinery physical property methods. Synthesis Parameters The Synthesis Parameters page on the Calculation Defaults tab displays the default values used for the refinery assay synthesis. You can use the default values or, optionally, modify the values. All default values display in red. If you modify any parameter or method, the value is displayed in blue text. 356 v Refinery Assays Refer to Synthesis Calculation Hierarchy for more information about methods and properties. Cloud Point Synthesis: Convergence Tolerance This parameter has no effect in Petro-SIM version 4 and higher. Cloud Point Synthesis: Fix Estimated Cloud Point at 600°C This option controls the addition of an extra fixed cloud point at 600°C (1112°F) in the cloud point synthesis, provided there is not already a measured or derived cloud point beyond 600°C. This fixed cloud point is based on the highest measured or derived cloud point and is used to anchor the curve. By default the checkbox is selected. Cloud Point Synthesis: Initial Fixed Cloud Point at 176.7°C This option sets a fixed cloud point at a boiling point of 176.7°C (350°F) in the cloud point synthesis. This is only used if a cloud point has not been given, the stream ABP is less than 176.7°C (350°F), and a freeze point is not available. The default value is -69.4°C (-93°F). Cloud Point Synthesis: Initial Fixed Cloud Point at 176.7°C for FCCU This option sets a fixed cloud point at a boiling point of 176.7°C (350°F) in the cloud point synthesis of an FCCU product stream (Type FCCU). This is only used if a cloud point has not been given, the stream ABP is less than 176.7°C (350°F), and a freeze point is not available. The default value is -40°C. v 357 Chapter 5: Oil Characterization Environment Cloud Point Synthesis: Use Residue Streams This option determines whether to include residue stream data in cloud point synthesis. The default excludes residue streams cloud points. Cloud/Pour Synthesis: Maximum Cut Width of Stream This option sets the maximum cut width for overlapping cuts used in cloud point and pour point syntheses. The default temperature range is 150.0°C (302°F). If an overlapping cut width is outside the specified range, synthesis ignores the cold property data and generates a warning message. Cloud/Pour Synthesis: Top Stream ABP for Cloud<>Pour Conversion This option controls the estimation of cold property data for cuts. Where the average boiling point of a cut is below this temperature (default 500°C or 932°F), synthesis will estimate missing cut cloud point values from the cut pour point values where available. Similarly it will estimate missing our point values from available cloud points. Conradson carbon content: Use residue streams Viscous streams such as residues are difficult to measure and are often in error: synthesis excludes them by default. Use this parameter to have synthesis take overlapping residue measurements into account. Synthesis will always use the concarbon measurement of the residue contiguous cut where available. Diagnostics This option allows the synthesis diagnostic output to be turned on or off. The default is yes to turn diagnostics on. Naphtha modification: Adjust naphtha components This parameter controls how synthesis handles situations in the naphtha boiling region (typically C6 to 200 C) when the available material in that region determined from TBP cuts is different from that determined from pure component and naphtha component data. There are four options: l l l l No – naphtha data takes precedence. Prorate to match TBP where higher Prorate to match TBP Volume Prorate to match TBP Weight Consider a scenario where the naphtha component sum is 10 lv% and the TBP composition curve sum is 12 lv%. Here the first two options have the same effect. The 2 lv% yield discrepancy is 358 v Refinery Assays accounted for by retaining a proportion of material in pseudocomponents. In the third option, Prorate to match TBP Volume, the naphtha component distribution is normalised to match the 12 lv% figure from the TBP yields, with pure/naphtha components defining all the material in the range. In the opposite case where the naphtha component sum is greater than the sum under the TBP curve, the options have the following effects: l l l Where naphtha data takes precedence, the TBP yield is adjusted to match the higher naphtha component sum by taking material from pseudocomponents immediately above the naphtha region. When prorated to match TBP where higher (the default), the naphtha components will be adjusted down to match the lower TBP yield. Prorate to match TBP Volume here has the same effect as the previous option, reducing the naphtha components. Naphtha modification: Adjust naphtha components by Volume This parameter has no effect in Petro-SIM version 4 and higher. Naphtha modification: Mass balance This parameter has no effect in Petro-SIM version 4 and higher. Naphtha modification: Octane balance This parameter has no effect in Petro-SIM version 4 and higher. Naphtha modification: Retain cut-points This parameter causes the naphtha component yields to be adjusted such that the original TBP Cut yields are preserved. There are three options: l l l No – no adjustment takes place Yes – adjustment takes place where it can Yes unless components sum > 50% - option applies except where naphtha represents a significant portion of the assay. This is the default. Discrepancies between the naphtha component boiling points and the TBP curve can become large when there are many naphtha cuts (contiguous and overlapping). The adjustment algorithm will automatically turn itself off when the required yield adjustments become too high. Naphtha modification: Split balance Affects how naphtha component sum is resolved against the TBP curve for material boiling v 359 Chapter 5: Oil Characterization Environment above 200 C which are typically C10+ Aromatics compounds. This parameter only takes effect where the value is YES and the naphtha components are being prorated to match the equivalent TBP Volume or Weight. YES then causes naphtha components boiling at or below 200 C to be prorated and those above 200 C to be left alone. If you leave the setting as NO, it means that the prorating region will extend to the highest boiling point of the non-zero naphtha components. This tends to skew the naphtha components too heavily at the higher boiling end. Naphtha modification: Volume balance This parameter has no effect in Petro-SIM version 4 and higher. Naphtha modification: estimate components This parameter controls the application of estimation rules for naphtha components. Options are: l l l l l Do not estimate Estimate groups from C9+ - will estimate missing PIONA groups from C9 to C11 using information on bulk PIONA and the given C6 to C8 information (default) Estimate detail for known groups – will estimate an isomer breakdown from each known carbon group Estimate detail for known and estimated groups – will estimate an isomer breakdown from any available group information Estimate as much as possible – will estimate all naphtha detail from bulk PIONA Naphtha modification: Scope This parameter controls the boiling range that will have its properties modified to be consistent with the naphtha component data. This parameter only takes effect where Perform Naphtha Modification is Yes or Partial. Options are: l l l Modify properties over full estimated range (default) Modify properties over measured range only - will only modify properties in the region defined by component measurements Modify properties up to Limit Temperature - limits modification to the lesser of the Limit Temperature parameter and the estimated range Naphtha modification: Limit Temperature This parameter sets the Limit Temperature value used in conjunction with the Scope parameter above. The default value is 180 Celsius: when applied, pseudocomponents above this temperature may contain detailed naphtha component data but the pseudocomponent properties will not be modified to be consistent with the detail 360 v Refinery Assays Octane Synthesis: Convergence Tolerance This parameter has no effect in Petro-SIM version 4 and higher. Overlapping Distillation Cuts This parameter causes synthesis to increase the number of iterations it allows in property convergence. This can improve the match against measurements for situations where distillations are used instead of TBP cuts. Perform Naphtha Modification Controls how naphtha component data in Naphtha Components and Update Naphtha cuts are processed by synthesis. There are 3 options: l l l Yes – will create an assay where the pseudocomponent and naphtha composition information are as consistent as possible, with pseudocomponent properties derived from pure component data where appropriate. Partial – creates an assay that has compositional consistency. Pseudocomponent properties will be taken from synthesis of widecut properties, falling back on pure component data in the absence of measurements. No – naphtha component information will be stored as-is with no guarantee of compositional consistency. Naphtha component information will be used to derive octane property curves in the absence of widecut data but other properties will be unaffected, Option is provided for consistency with older versions and is not recommended for new users. Pour Point Synthesis: Convergence Tolerance This parameter has no effect in Petro-SIM version 4 and higher. Pour Point Synthesis: Curve Peaks at this Temperature Pour point typically increases up to the specified boiling temperature and then starts reducing. The default is 560.0°C (1040°F). The parameter does not apply to the Levenberg-Marquardt pour point synthesis method. Pour Point Synthesis: Tolerance for Residue Stream This parameter has no effect in Petro-SIM version 4 and higher. Pour Point Synthesis: Use Residue Streams This option indicates whether the synthesis is to include the pour points for all residue streams. The No is selected by default, which excludes residue pour points. However, in the final section v 361 Chapter 5: Oil Characterization Environment of the synthesis, the program always uses the widest residue stream pour point to define the shape of the backend of the pour point curve (beyond the peak). Pour Point Synthesis: Use Streams with Viscosity at 50°C (122°F) 2000 cSt. This parameter determines whether the model is to include pour point data for streams with high viscosities in the synthesis. The No is selected by default, which excludes pour points for streams with viscosities greater than 2000 cSt at 50.0°C (122°F). SG Synthesis: Allow SG Inversion Above This Temperature This parameter is used in conjunction with the synthesis of hydrocracker reactor product only. It gives the temperature above which the hydrocracker stream type operates, allowing the SG curve inversion. The default is 300.0°C (572°F). SG Synthesis: Use Residue Streams This parameter has no effect in Petro-SIM version 4 and higher. Overlapping residue stream measurements will always be used. TBP Synthesis: Give Priority to Yields The primary goal of synthesis is to derive a composition and density curve that matches the laboratory cut yields on both a weight and volume basis. Synthesis will match as best it can but small discrepancies can arise which will appear by default as mismatches in reported cut yields. Here the yields are calculated by cutting the synthesized assay at the input cut points. A value of Yes changes how synthesis reports, where it will instead recalculate the cut points that will meet the input yields. This is the approach used by version 3 and earlier of Petro-SIM. TBP Synthesis: Resynthesize if >50% of the Assay Boils Below 221°C For light boiling streams, accuracy of the TBP synthesis is improved by allowing a resynthesis. This recuts the synthesized TBP curve into 13 cuts and uses a spline fit to recalculate the individual component compositions. Default for this switch is yes. Update composition from Update Cuts When data is provided for an update cut, either a pure component composition, or a distillation or an initial and final TBP cut point must be provided to complete the data requirements of the plantdata stream. By default (this parameter value - no), the composition values for update cuts are not used to modify the assay TBP curve. Setting this parameter to yes updates the assay TBP curve with update cut values. 362 v Refinery Assays Update density from Update Cuts When data is provided for an update cut, a density value must be provided to complete the data requirements of the plantdata stream. By default (this parameter value is No), the density values for update cuts are not used to modify the assay SG curve. Setting this parameter to Yes updates the assay SG curve with update cut values. Use Flowsheet Components This parameter has no effect in Petro-SIM version 4 and higher. Use update values alone if there are as many values as from other cuts If there are as many or more property values for a particular property in update cuts than there are in non update cuts then setting this flag to yes (the default) ignores the property values in non update cuts and performs the property synthesis using update cut property data alone. Use update values alone if there are this number of values or more If property values are provided in update cuts, they will be used to modify the property curves synthesized from the property data of non update cuts. In some cases, there is sufficient data in the update cuts to do a complete synthesis from the update data without generating a curve shape from non update cuts first. This parameter is used to set the number of update cut property values that must be available before the non update cut values are ignored. The default is 6 but many assay syntheses may benefit from a lower value if there is a significant amount of update cut property data. Viscosity Synthesis: Switch method if viscosity at 100°C > 5000cSt For highly viscous assays, the viscosity method that balances on the widest residue cut rather than the narrowest residue cut (see synthesis methods) tends to give better results. If this switch is set to yes (the default) and the whole assay viscosity at 100°C > 5000cSt and the viscosity synthesis method is set to balance on the narrowest residue cut then the viscosity synthesis method is automatically changed for the current synthesis only to the widest residue cut and the synthesis of viscosity is repeated. Synthesis Methods The Synthesis Methods page on the Calculation Defaults tab displays the default values used for the refinery assay synthesis. You can use the default values or, optionally, modify the values. All default values display in red. If you modify any parameter or method, the value is displayed in blue text. v 363 Chapter 5: Oil Characterization Environment Refer to Synthesis Calculation Hierarchy for more information about methods and properties. Cloud Cut Width Definition Cloud Cut Width defines the TBP cut range width calculation method for Cloud Point calculations. The following three methods exist for this calculation. l l l 1% to 99% method, the default uses the 1% - 99% distillation values to determine the width of the stream for cloud point calculations. TBP Cut Points method uses the TBP cutpoints of the stream as the width of the stream. User specified cut width method makes a linear extrapolation through the TBP 70% and 30% distillation points to determine a pseudo TBP cut range for cloud point calculations. With the latter, you can adjust the distillation points used through the Cloud Cut Range Parameter. Molecular Weight Two methods are available for this parameter. The Component Molecular Weight controls the way to synthesize molecular weight. The default is API (based on component SG and ABP) method. API (based on component SG and ABP) method is the API method without a correction for asphaltenes content. 364 v Refinery Assays API + asphaltenes correction above 400C method is the API method based on the component specific gravity and boiling point. An upwards correction is applied to the molecular weight of the higher boiling range material (above 400°C or 752°F), based on the assay asphaltenes content. Nitrogen Synthesis Two methods are available for synthesizing nitrogen content. The quadratic spline fit method uses a quadratic spline fit procedure to generate the nitrogen distribution curve in the nitrogen synthesis. The logarithmic quadratic spline fit method uses a logarithmic quadratic spline fit curve in the nitrogen synthesis. This produces a better match of the very low nitrogen values in the light cuts. Octane Synthesis Method used to determine the octane property curve shapes. l l l Typical crude template uses a template based on crude assay octane distributions Typical FCC gasoline template takes a single octane template and manipulates it to match given octane values in 1, 2 or 3 streams in the gasoline range. FCC-Sim Template uses the template method of FCC-SIM, manipulating a starting template to match given octane values. Olefin Synthesis Method used to determine the olefin content property curve shape. The FCCU Template method is specifically for FCCU reactor product streams and imposes a characteristic curve on the property. Residue Distillation Generation Synthesis can generate distillations for atmospheric residues or vacuum unit side streams and residues when no data is available. The generation works by estimating the volume interchange and then using that to derive distillations. All three calculation methods use a quadratic equation based on the stripping steam rate to calculate the volume interchange between the residue stream and the next lighter product. The only difference between the methods is in the coefficients of the equation. This option only takes effect if you set up a residue stream from an atmospheric or vacuum column as a synthesis cut, without giving a distillation, and synthesize a refinery assay using this cut as the heaviest stream in the synthesis. To show that the residue stream is from a vacuum column, use the property Stream type with a value of Vac Residue in cut. Identify all other cuts v 365 Chapter 5: Oil Characterization Environment from the vacuum column as Stream Type VDU. Specify stripping steam rates used in the field with either the Stripping Steam Flow or Stripping Steam Ratio specifications within the appropriate cuts. Specific Gravity Synthesis Two methods are available for determining the way Specific Gravity is synthesized. The Quadratic spline fit method uses a quadratic spline fit procedure to generate the specific gravity distribution curve in the specific gravity synthesis. The Cubic spline fit method, which uses a cubic spline fit procedure to generate the specific gravity curve, produces a smoother curve. TBP Synthesis Three methods are available for determining how the TBP curve is synthesized. The Quadratic spline fit method uses a quadratic spline fit procedure to generate a TBP curve from Plant Data TBP cutpoints. The Cubic spline fit method uses a cubic spline fit procedure to generate the TBP curve from Plant Data TBP cutpoints. This gives a smoother curve than the Quadratic spline fit method. The Cubic spline fit + smoothing method uses a data reconciliation techniques to smooth the crude TBP curve generated from distillation data, greatly reducing any noise in the distillation measurements. Viscosity Synthesis Viscosity values can either be balanced to match the narrowest residue overlapping cut (the default) or the widest residue cut. Balancing on the widest residue cut typically gives better results on high viscosity assays. The method can be automatically switched to use the widest residue cut for high viscosity values if the synthesis parameter “Viscosity synthesis: Switch method if viscosity at 100°C > 5000cSt” is set to Yes. In common with other synthesis methods, viscosity synthesis will apply an optimization technique to minimize the error between the synthesized curve and the measured points. You can suppress this optimization and have synthesis use an adjustment scheme that matches the back end only by changing the Synthesis Technology method to Traditional. This method only affects viscosity synthesis. Ca Cn Estimation Methods Method used to estimate the core aromatics, naphthenes and olefins properties. l l 366 v The Estimate from RI method uses the Refractive Index to calculate the carbon molecules in aromatics and naphthenes. The Estimate from SG and Viscosity method uses the specific gravity and the viscosity of of the pseudo components to generate the Ca Cn property curve. Refinery Assays l The Local option suppresses synthesis of core aromatics, naphthenes and olefins, with reactors that need the properties estimating values from stream SG and Viscosity properties. Pour Point Synthesis There are two methods for determing the way the Pour Point curve is generated. The WeightedLeast Squares approach is consistent with the way all other property curves are synthesized in v4. The Levenberg Marquardt method uses an optimized fifth order polynomial to draw the property curve. This approach is beneifical for finding the pour point depression that occurs at the tail end of the property curve. Pour Point Synthesis – End Point When the Pour Point method is set to the Levenberg Marquardt method, the end point of the property curve can be calculated using either the last point on the Cloud Point curve or straight line using the last two remaing points of the Pour Point curve. Physical Property Parameters The Physical Property Parameters page on the Calculation Defaults tab displays the default values used for the refinery assay synthesis. You can use the default values or, optionally, modify the values. All default values display in red. If you modify any parameter or method, the value is displayed in blue text. v 367 Chapter 5: Oil Characterization Environment Refer to Synthesis Calculation Hierarchy for more information about methods and properties. Distillation Parameters These parameters affect the calculation of TBP, D86 and D1160 distillations from stream composition and in particular the definition of what constitutes the initial and final boiling point. l l l l IBP for distillations sets the percentage cumulative composition that represents the Initial Boiling Point of the material. It defaults to 0.5 lv%. FBP for distillations sets the percentage cumulative composition that represents the Final Boiling Point of the material. It defaults to 99.5 lv%. Basis for IBP and FBP sets the units of measure used with the IBP and FBP for distillations parameters. options are Volume, Mass or Mol. Component cutoff vol% for calculating TBP initial and final points sets a threshold for handling trace components that can appear in predicted stream compositions. The default value is 0.0001 lv% and components with a liquid volume percent composition below this point will be ignored. CARB Parameters These parameters set default behaviour for the CARB (California Air Resources Board) gasoline property calculations. The following parameters control whether the calculations are to a Flat or Average limit, where the choice of limit used will be one determined by each producing or importing gasoline seller: l l l l l l CARB Aromatics CARB Benzene CARB Olefins CARB Sulfur CARB D86 50% CARB D86 90% You can also set the oxygen limits that apply in the calculations: l l CARB Min O2 Level CARB Mxx O2 Level Cloud point blending: offset factor a (intercept) and offset factor b (slope) Calculated cloud points can be modified by a calculated offset determined from a straight-line formula Offset = A + B*CloudPoint 368 v Refinery Assays Where l l Cloud point blending: offset factor a (intercept) is the A term in this equation and has units of temperature. Cloud point blending: offset factor b (slope) is the B term in this equation and has units of temperature difference Both A and B default to zero, meaning the offset will also be zero. Lowest boiling temperature for material containing asphaltenes This parameter sets the boiling temperature (default = 600 C, 1112 F) below which asphaltenes do not occur. Standard Temperature, Standard Pressure, Reference Density of Water, and Reference Water Temperature These parameters define what is meant by standard conditions for the purposes of converting between density measurements and specific gravity and API Gravity values. Internally all PetroSIM ideal component densities are recorded at 60°F (15.5°C), but your local measurement standard may be a different temperature such as 15°C which is common in Europe or 20°C. You should change these parameters to reflect your local practice. Any Specific Gravity (Dry) or API Gravity (Dry) measurements you give, or any values for SG or API Gravity you give at standard conditions will be converted form your standard conditions to density at 60°F. Physical Property Methods The Physical Property Methods page on the Calculation Defaults tab displays the default values used for the refinery assay synthesis. You can use the default values or, optionally, modify the values. All default values display in red. If you modify any parameter or method, the value is displayed in blue text. v 369 Chapter 5: Oil Characterization Environment Refer to Synthesis Calculation Hierarchy for more information about methods and properties. C to H Ratio Calculation Two methods exist for the C to H Ratio. The Based on component SG and ABP method, the default, calculates the carbon-to-hydrogen ratio using one of a series of correlations based on the feed average boiling point. Derived from n-paraffins C/H curve method uses a single equation over the whole boiling range. Calculation Basis for concentrations The Calculation Basis for concentrations sets whether concentration properties such as sulfur content or Benzene content report on a wet or dry basis. The default for Refining is dry, while Production reports on a wet or whole stream basis. Cetane index ASTM D4737 - Methods There are three different ways of calculating Cetane Index using the ASTM D4737 equations: 370 v Refinery Assays Method Description ASTM D4737-04 This equation is the original D4737 procedure that is now known also as D4737-09a Procedure A. It was developed for diesel fuels meeting the requirements of Specification D975 Grades No. 1–D S15, No. 1–D S500, No. 1–D S5000, No. 2–D S5000, and No. 4–D. ASTM D473709a This implements Procedure B of the D4737-09a standard and is applicable for diesel fuels meeting the requirements of D975 Grade 2-D S15 and 2-D S500. ASTM D473709a Fahrenheit conversion Included for completeness, this method implements Procedure B in its Fahrenheit definition. The blending index equation is described under Cloud Index Factors and all the coefficients may be input. Petro-SIM applies a stream width correction with default or input coefficients. It then applies an offset based on the cloud point value. The coefficients of the offset equation are set by the Cloud Offset Factors option. Cloud Point The following five methods exist for the determination of Cloud Point: Method Description Factor method + This is the default method, the Refinery hypocomponent factor method. stream width correction + offset Factor method + tail adjustment + offset Similar to the previous method, but has a different adjustment for the distillation tail above 90%. Factor method + The Refinery hypocomponent factor method, but with an extra adjustment for extra correction very wide streams. for very wide cuts + offset v 371 Chapter 5: Oil Characterization Environment Method Description Factor method, Similar to Factor method + stream width correction method except that it does no width not apply a stream width correction to calculated cloud points. This method correction + offset has been used as a base method to calculate required correction factors. It is not recommended to use this as a general purpose cloud point prediction method. Index method + Uses an index method, but is otherwise the same as the first method in this cut width table. correction + offset The blending index equation is described under Cloud Index Factors and all the coefficients may be input. Petro-SIM applies a stream width correction with default or input coefficients. It then applies an offset based on the cloud point value. The coefficients of the offset equation are set by the Cloud Offset Factors option. Density Three methods are available for determining the way specific gravity and liquid density are calculated. l l l The default, method 1, described in Refinery Physical Properties, is derived from thermal expansion curves in Maxwell’s book (Maxwell, J B, Data Book on Hydrocarbons; Application to Hydrocarbons, NY, Van Nostrand, 1950). At certain conditions this method may be invalid, since a density calculated at 60°F is not the same as the specific gravity of the stream. Method 2 uses the Maxwell calculation method, but ratios the volume expansion with the value calculated at 60°F. This method maintains the rate of volume expansion with the temperature predicted by Maxwell, and guarantees that a density calculated at 60°F is the same as the specific gravity of the stream. Method 3 is the API recommended procedure 6A3.6, 1992, which guarantees that a density calculated at 60°F is the same as the specific gravity of the stream. The stated accuracy is an average error of 0.75% when tested against a data set consisting of high molecular weight hydrocarbons. Distillation ASTM D1160 ASTM D1160 distillation is calculated using one of two methods. The KBC method (the default) is provided for compatibility with previous releases. The other method is an API method, details of which can be found in API documentation. 372 v Refinery Assays Distillation ASTM D86 ASTM D86 distillation is calculated using one of four methods. The KBC method is provided for compatibility with previous releases. The other 3 methods are API methods, details of which can be found in API documentation. The default is the API 1974 method. Distillation D2887 ASTM D2887 distillation is calculated using one of four methods. The KBC method (the default) is provided for compatibility with previous releases. The other 3 methods are API methods, details of which can be found in API documentation. Distillation TBP Three methods are available for the calculation of TBP distillation from component composition. Straight line interpolation (the default) uses a lever arm rule to determine the temperature at each TBP lv%. Spline interpolation uses a quadratic spline to determine the temperature at each TBP lv%. The Petro-SIM Boiling Point Utility method uses a combination of spline interpolation techniques and provides identical results to the boiling point utility within Petro-SIM. Enthalpy Calculation If the Thermodynamic calculations method (see below) is set to API shortcut, then this method is used to determine exactly which shortcut method to use for enthalpy calculations. If the Thermodynamic calculations method is set to Use fluid package, then this method setting is ignored. Details of the methods can be found in the physical properties documentation. Flash Point ASTM/PMCC The ASTM/PMCC flash point calculation method uses either the 1% and 5% or the 10% distillation point of the stream to estimate the flash point value. The default is to use the 1% and 5% values. K-values calculation If the Thermodynamic calculations method (see below) is set to API shortcut, then this method is used to determine exactly which shortcut method to use for K-values calculations. If the Thermodynamic calculations method is set to Use fluid package, then this method setting is ignored. Details of the methods can be found in the physical properties documentation. Maximum visbreaker conversion The KBC (1987) method is the default for existing cases. The revised KBC (2005) method gives much improved results and is the default for all new cases. Details of the methods can be found in the physical properties documentation. v 373 Chapter 5: Oil Characterization Environment Motor octane number Calculate motor octane number distribution (clear and leaded) using one of three methods: (1) the KBC index method, (2) the straight volumetric average method or (3) the Ethyl RT-70 method. We recommend you use the same method to calculate research and motor octane numbers. PONA Interconversion Two methods are available for how stream PONA contents (paraffins, olefins, naphthenes, aromatics and related properties) are converted between a weight and liquid volume basis. The methods apply during assay synthesis when you provide data on a wt% basis and during stream property calculation when wt% values are calculated from the assay vol% profiles. l l Fixed ratios between PONA Types uses constant nominal densities for the different PONA species. This method is consistent with the approach used in Petro-SIM 4.0 and 4.1. Dynamic ratio based on characterization function calculates the ratio as a function of the PONA-type density of the mean average carbon number of the stream, determining densities at that carbon number from carbon number versus density relationships. This method is the default. Pour point Three methods are available for determining the way pour point is synthesized. The default, Factor method + stream width correction method, is equivalent to the default cloud point 1% to 99% method. The Factor method, no stream width correction method is similar, but doesn’t apply a delta correction based on stream width. The Factor method + extra adjustment for very wide cuts method is equivalent to cloud point User specified cut width method. Refractive index Two methods are available for determining the refractive index. The Weight blend method is the default method. Petro-SIM calculates assay and stream refractive index values on a weight basis. Blending and de-blending is also done on a weight basis. The Hot volume blend method calculates refractive index on a volume basis, with volumes calculated at the temperature of the refractive index measurement. Petro-SIM stores refinery assay values for refractive index at 67 ºC, so all blending and de-blending calculations are done using liquid volumes at this temperature. Reid vapour pressure Two methods are available for determining the Reid vapour pressure contribution method. The Convert component TVP to RVP; Blend RVP’s method first converts each component TVP value stored in the assay to RVP, then blends stream RVP on a component volume index basis. The Blend TVPs; Convert to RVP method first blends TVP on a component molar basis, then converts the resulting TVP to RVP. 374 v Refinery Assays Research octane number The available methods for calculating research octane numbers (clear and leaded) are the same as those for motor octane numbers (see earlier). It is recommended that you use the same method to calculate research and motor octane numbers. TBP weight to TBP volume conversion Two methods are available for determining the conversion between TBP distillations on a weight and volume basis. The Stream SG method uses specific gravity values to calculate TBP lv% from TBP wt% distillation data, or the converse. The ASTM D2887 method uses the ASTM D2887 procedure, and is based on correlations using a D86 distillation. It can only be used to convert TBP wt% to TBP lv%. The procedure is not reversible. The correlations can only be applied accurately between - 45.5°C (114°F) for the 1% point and 405.5°C (762°F) for the 99% point. Outside this range, the program reverts to the Stream SG method, and issues a warning message. Thermodynamic calculations Thermodynamics; i.e. enthalpy, k-values and phase splits within refinery reactor models can be calculated using an internal KBC/API shortcut method (the default for previous versions of PetroSIM) or can be calculated using the Petro-SIM thermodynamic method selected within the fluid package for the streams connected to the refinery reactor model (the default for all new flowsheets). The ability to use the Petro-SIM thermodynamics is recommended for all new flowsheets as it ensures enthalpy balances around reactor models and that reactor products are of the right phase. It may be appropriate to convert legacy flowsheets to use the Petro-SIM thermodynamic calculations. Viscosity (Kinematic) Two methods are available for determining the viscosity parameter. The Weight blend using VBN method is the default method. Petro-SIM calculates assay and stream viscosity values on a weight basis. Blending and de-blending is also done on a weight basis. The Hot volume blend method calculates viscosity on a volume basis, with volumes calculated at the temperature of the viscosity measurement. Petro-SIM stores assay values for viscosity at 50 ºC (122°F) and 100 ºC (212°F), so all blending and de-blending calculations are done using liquid volumes at these temperatures. Viscosity in Furnace/Visbreaker tubes This parameter controls how the effective viscosity of material is calculated from the viscosity of the liquid and vapor phases in tubes of the Fired Heater, Visbreaker, VGO Cracker, and Coker v 375 Chapter 5: Oil Characterization Environment Furnace unit operations. Three methods are available: l l l Interpolation using actual LV% vaporized (1), blends liquid and vapor viscosities, using densities at actual conditions. Actual LV% vaporized (2), blends liquid and vapor viscosities, using densities at standard conditions. Liquid viscosity (3), which ignores any effect of vapor viscosity. Your choice of calculation method is the most influential item in predicting furnace pressure drop for any given set of operating conditions. Normally, method 1 should be used but we recommend using method 2 when modeling furnaces for vacuum towers. If you select method 3, the program calculates frictional pressure drops, based on the single phase equation throughout the mixed phase region. You may require this method if low throughput or high liquid viscosities cause phase separation. It tends to produce higher pressure drops than the two phase equation used with methods 1 and 2. Import Refinery Assays To import a refinery assay from an external file, from the Refinery Assay tab of the Oil Environment, click Import. Select one of the following options: Refinery Assay Files From the File Selection for Importing a Refinery Assay view, select the assay file that you want to open. Alternatively, you can use the Files of Type drop-down list to filter the files displayed. 376 v Refinery Assays Select... Typical Refinery Assay Files To display only files of this Description type... *.asy *.ast. Default selection. Displays all assay files with the specified file name suffix.. *.XML *.cru Refinery Assays in XML Format *.XML Displays only assay XML files. Petro-SIM Database *.db Displays files that were saved as database files. See Databases for more information about saving files to the database. Refinery Assays *.asy Displays only complete assay files which includes fluid packages, component lists, source information, and assay matrix information. Refinery Assay Templates *.ast Displays only assay templates. Select a template to open an new case based on the template. H/CAMS Blend CRU File *.cru Displays only H/CAMS Blend CRU files. You must have the appropriate v 377 Chapter 5: Oil Characterization Environment Select... To display only files of this Description type... components from Haverly configured on your system (HCAMSCOM.HCams). Importing an H/CAMS crude by browsing for the .CRU file manually bypasses the Haverly Crude Selector, resulting in a shorter assay name and no notes. All Files *.* Displays all files in the selected folder. H/CAMS The Select Crudes (Haverly Crude Selector) view displays the available assays. You must have the appropriate Haverly components on your system and a valid license to use this feature (that is, HCAMSCOM.HCams). 1. Select the assays that you want to open from the top list and use the transfer them to the list of selected assays at the bottom of the view. 2. Click 378 v to import the assays into Petro-SIM. button to Refinery Assays Importing a CRU file creates a Petro-SIM refinery assay that includes a number of plant data groups and cuts with properties. These imports are controlled by the contents of the file HCams_Map.xml in the Petro-SIM support directory. This file specifies how cuts are generated and how Haverly properties are mapped to Petro-SIM. If necessary, you can edit this file, but the default settings are as recommended by Haverly and KBC and carefully configured and tested to support a wide range of assays. Petro-SIM imports one Haverly crude in its entirety (for maximum flexibility). Any blending or cutting can be done by using one of various Petro-SIM unit operations. Alternatively, you can also select Import, Refinery Assay Files, and then manually browse for .CRU files. If you use the crude selector to browse for an assay, Petro-SIM creates a longer name for the assay and the assay notes (visible on the Notes tab of the refinery assay view). You can also set the default assay name and short assay name (typically used for LP generation) in your Preferences (Files tab, Import Export page). CADB Installation The Assay Selection view displays a list of assays that you can filter by region. You must be a licensed user to access some CADB assay files, and these assays must first be installed on your system. 1. To filter the assays by geographical region, check Group by Region. 2. Select the CADB Year from the drop-down list. 3. In the Selected Assay Information group, optionally,enter filter criteria in the Min and Max Filter cells for any of the properties. 4. Select the assays that you want to import (use the CTRL or Shift key to select multiple assays). When you select an assay, the bulk property values are shown in the bottom grid. 5. Optionally, change the name for the imported assay in the Import selected assay using the name field. v 379 Chapter 5: Oil Characterization Environment 6. Check Only Import Assay Matrix to exclude synthesis data. 7. Click Import Selected Assay to import the selected assays. Petro-SIM Database The Assay Selection view displays a list of assays that are in your Database Collections. You must be connected to a Petro-SIM database. 1. In the Selected Assay Information group, optionally, enter filter criteria in the Min and Max Filter cells for any of the properties in the grid. 2. Select the assays that you want to import (use the CTRL or Shift key to select multiple assays). When you select an assay, the bulk property values are shown in the bottom grid. 3. Optionally, change the name for the imported assay in the Import selected assay using the name field. 380 v Refinery Assays 4. Check Only Import Assay Matrix to exclude synthesis data. 5. To check out the assay from the database for exclusive revisions, select Check Out. 6. Click Import Selected Assay to import the selected assays. Export Refinery Assays Before exporting refinery assay information to an external file, be aware of the differences between formats as each format stores different levels of the refinery assay object . The full refinery assay object contains: l l l Fluid Package and Component List details. Refinery assay data matrix details. Refinery assay source information which, depending upon the source of the refinery assay (database, synthesis, or flowsheet stream), has the following characteristics: o If imported from an assay database (*.adb), full path name of the database and name of the imported assay are all that are visible. No source information is available. v 381 Chapter 5: Oil Characterization Environment o o If synthesized, all synthesis data (cuts, properties, methods etc.) are included in the source information. If derived from a flowsheet stream, the name of the original stream and date and time saved from flowsheet are included in the source information. In the File Selection for Exporting a Refinery Assay view, select one of the following options: XML File 1. In the File Selection for Exporting a Refinery Assay view, enter a File name for the assay, and then click Save. 2. In the XML File Exchange view, select these export options: Check... To... Minimize XML Information Include only the synthesis data. Use User Units Include the user specified units. Include Source Information Include source information (described above) Include Assay Matrix Include assay data matrix details. Generate for V3 Save the XML file as a Petro-SIM version 3 format. Apply settings to all exports Save the export settings for future exports. 3. Click Export. The assay object is exported to an XML file. Petro-SIM Database / Petro-SIM Database With New Name Use these options to export the complete assay object to a database. You must be connected to a non-version controlled database. 382 v Refinery Assays If you are connected to a database that supports version control, these options are not available. Use the Publish option instead. l l Select Petro-SIM Database to export the assay object to a database. All assay data is exported to your database immediately without displaying a dialog confirmation box. Select Petro-SIM Database With New Name to export the assay object to the database under a new name. In the Assay Selection view, change the name in the Export as field and then click Export Assay. When exporting to a Petro-SIM database, all inputs and results are saved. If you make changes and re-save a database assay, it creates a new revision of the assay in the database. This allows you to track how an assay has changed over time, as you can import any revision into PetroSIM. Refinery Assay as Template Select this option to export only input data into a Refinery Assay Template (*.ast) file type. v 383 Chapter 5: Oil Characterization Environment This option is useful for standardized laboratory data, allowing you to re-use properties and cuts each time you want to synthesize an assay. Custom-built assay template files can be used as a starting point to enter sample data. Synthesis data supplied with the refinery assay can be useful where you want to create the assay in a different case using a different component list and/or Fluid Package. Assay And Fluid Package Select this option to export the refinery assay and fluid package to a Refinery Assay (*.asy) file type, including the entire refinery assay, including the Fluid Package, Component List, data matrix and source information. This format is useful when you want to use re-use a refinery assay in different cases. Publish Refinery Assays If you are connected to a database that supports assay version control, you have various options for exporting assays to the database. 1. To publish an assay from the Oil Characterization Environment, click Publish and choose New Assay. 2. In the Assay Selection view, optionally, change the name of the assay in the Export field. 384 v Refinery Assays 3. Check Make Public if you want the assay available to other users from the database. 4. Click Export Assay. The assay is published to the database. Users who connect to the database can import or check out the assay exclusively and make Private or Public Revision updates. Update Assays in the Database 1. To make updates to a refinery assay in the database, select the assay in the Oil Characterization Environment, and then click Check Out. This locks the assay so that no other user can simultaneously make changes. 2. Modify or update the assay and when you are done with changes, select one of the following options: l Publish, Private Revision – Checks in the assay to the database hiding your updates from other users. If you open a case that is linked to the assay, it is updated and you can examine the effects of your changes. If other users open the same case, they do not see any changes. v 385 Chapter 5: Oil Characterization Environment l l Publish, Public Revision – Checks in the assay to the database committing your updates to the assay in the database. If any user now opens a case linked to the database assay, it will be updated and resolved in the case. Revert – Checks in the assay to the database reverting all intermediate revisions and restoring the assay to its initial state. Assay Data Matrix The Assay Data Matrix view displays the selected assay matrix data for both synthesized refinery assays and imported assays. From the Refinery Assay tab, click View Data Matrix in the Refinery Assay Information area. You can view the data as a table or plot. Assay Property Table The Assay Property Table displays all assay properties for the selected assay in tables. In the Select Assay Properties to Display list, check the boxes next to the property names that you want to display. The Assay Properties Value matrix is updated to show the property values. To view the properties by name or by both dimension and name, select the sort order option in the Use the Properties Sort Order group. Use the buttons to select all or clear all property selections. Right-click the grid background for more options. Assay Property Plot The Assay Property Plot tab lets you create plots showing various assay properties. 386 v Refinery Assays The Available Property Plots displays the plots set up for the selected assay. The Plotted Assay Property Curves displays the properties selected each plot. 1. To create a new plot, click Create Plot. You can also create a plot by clicking Characterization tab. Quick Plot on the Oil 2. In the Refinery Assay Property Plot view, check the boxes next to the assay properties that you want plotted. 3. When you select a property type, the Select Assay Properties to Plot group updates to display only related properties. v 387 Chapter 5: Oil Characterization Environment 4. Optionally, check these options: l Dry Basis to display the property data on a dry basis (no water). l Hide Light Ends to disregard the light ends of the oil characterization on the plot. 5. Use the buttons at the bottom to select all or clear all property selections. 6. Right-click the plot and select Graph Control for more plot options. Bulk Assay Processing Use the Petro-SIM Bulk Processing feature to process multiple assays. Assays can also be bulk processed programmatically via an OLE function call. 1. From the Oil Characterization tab on the ribbon, click Characterization tab. 388 v Bulk Process on the Oil Refinery Assays 2. In the Bulk Assay Processing view, click Select Assays and choose one of the following options to select the assays that you want to process: l CADB Installation displays the Assay Selection view where you can select CADB assay files that are installed on your system. l Petro-SIM Database displays the Assay Selection view where you can select assays from the database. l All Current Assays selects all assays in the current case. l All Selected Current Assays selects all assays that you have selected in the Refinery Assay tab. l Browse for Files opens the File Selection for Importing a Refinery Assay view where you can navigate to the file location and select the assay files that you want to process. l Browse for a Directory opens the Browse for Folder view where you can navigate to a folder location and select a particular directory. This is useful if the number of files you want to select exceeds the Windows file browser limit. l Clear to clear the list of previous selections and make a different selection. The selected assays are displayed in the Assays to Process area. 3. Select the one of the following Destinations: XML When you select XML, the Bulk Assay Processing view displays the following additional options: l l l Name prefix - Enter a prefix that is applied to each assay name as it is processed. This prefix should not contain parts of a file path. Export Path - Enter the directory where the assays are to be saved, or click Browse to navigate to and select a location. Generate for V3 - Check this box to export assays into XML V3 format. PetroSIM V3 does not recognize V4 XML formats. v 389 Chapter 5: Oil Characterization Environment Database You must be connected to the database before you can bulk process assays to it. 390 v Refinery Assays When you select Database, the Bulk Assay Processing view displays the database to which you are currently connected and additional options: l l Name prefix - Enter a prefix that is applied to each assay name as it is processed. This prefix should not contain parts of a file path. Generate Standard Cuts - Check this box to generate data for a particular set of cuts or plots for a number of assays. o Use Current Case - Check to use the current open simulation case to generate cuts, or the standard oil basecase (which contains a component splitter to generate a number of cuts from one feed) can be used. The database name for each case will be “SRC “ with the name of assay appended. o Assay Stream - Select which stream in the case each assay should be attached. If a stream name is not provided, Petro-SIM searches for any feed stream to which an assay can be attached and uses that stream. v 391 Chapter 5: Oil Characterization Environment l l l Overwrite Assay Revisions - If an assay already exists in the database, PetroSIM overwrites it with the new revision. If it does not exist, a new revision is created. Check Assay In - If the assay is not locked, the new revision is checked in. if you have it checked out, it is checked in and temporary waypoints are deleted. Use Assay Revisions - Saves the assays to the database as new revisions. If the assay is not under change control or if it does not exist, it is overwritten. Oil Manager When you select Oil Manager, you can import multiple assays from another source. The Bulk Assay Processing view displays this additional option: l 392 v Name prefix - Enter a prefix that is applied to each assay name as it is processed. This prefix should not contain parts of a file path. Refinery Assays If you selected All Current Assays or All Selected Current Assays, Petro-SIM does not process these assays. 4. When you are done selecting assays and the destination, click Process Assays to being processing. The assays are processed and then released one at a time. This allows for thousands of assays to be processed without reading them all into memory. Refinery Assay Synthesis Tutorial In this tutorial, you will create and synthesize a crude oil sample from laboratory data to generate a refinery assay. The assay is defined based on the following number of properties: Plant Data Group No. of No. of Properties Cuts Light Ends 7 2 Distillates 28 6 Residues 15 2 In total, 50 different properties are required for this synthesis. The crude oil distillation curve would look similar to the one shown below: Follow these steps to complete the refinery assay synthesis tutorial: v 393 Chapter 5: Oil Characterization Environment 1. 2. 3. 4. 5. 6. 7. 8. Initialize the Case Add a Plant Data Group Append a Cut Add Properties Add Measured Data Add Second Plant Data Group Add Third Plant Data Group Synthesize the Assay Initialize the Case Before you can start the synthesis process, you must initialize a new case: 1. Start Petro-SIM and open a new Petro-SIM Refining Case. This automatically sets up the default component list and fluid package. With the fluid package defined, you can now proceed to the Oil Characterization environment. 2. To open the Oil Characterization environment, click Oil in the Environment group on the Home tab. 3. Select the Refinery Assay tab if it's not already selected. 394 v Refinery Assays The Oil Characterization tab displays the different Petro-SIM Oil Characterization options. To synthesize a refinery assay, data for one or more properties of one or more contiguous cuts must be supplied. There are a number of minimum data requirements for a successful synthesis. Refer to Synthesizing a Refinery Assay for a list of these requirements. 4. From the Available Refinery Assays group, click Create to add a Plant Data Group to the new refinery assay. Add a Plant Data Group The Refinery Assay Source (Synthesized) view displays where you can add Plant Data Groups. Plant Data Groups allow you to group like-cuts in a refinery assay. Each Plant Data Group can have different property lists and any number of cuts. 1. To add a blank Plant Data Group, from the Input Summary tab, click Add. 2. In the Plant Data Group view, enter a new name in the Plant Data Group Name field. Because this Plant Data Group will be used to store light ends related property and cut details, rename it Light Ends. v 395 Chapter 5: Oil Characterization Environment You have successfully added your first Plant Data Group. The Plant Data Group: Refinery Assay-1: Light Ends grid starts out with basic information about one cut. By default, the grid shows a number of mandatory rows, which include the following: Cut Name Displays a unique name for the cut that is created for you when you add a cut, but you can change it to any name your prefer. Cut Type Choose from various cut types. Cut Status Displays whether a cut contains the minimum data necessary for use. Input/Calc Displays whether the column contains input data or calculated values. 3. Complete the grid by appending cuts. 396 v Refinery Assays Append a Cut 1. To add a cut to the Plant Data Group, click Append Cut. 2. In the Cut view, enter a cut name; re-name the cut to Gas. 3. From the Cut Type drop-down list, select Contiguous. For this cut type, the synthesis assumes that a set of contiguous cuts make up the original material. The Status Information group lists details relating to the current cut status. 4. Click OK to add the cut to the Plant Data Group. 5. Add another cut named, C5 Data, by repeating steps 1 through 4. The Plant Data Group view should now have two contiguous cuts named, Gas and C5 Data. v 397 Chapter 5: Oil Characterization Environment 6. Complete the Plant Data Group by adding properties. Add Properties The following steps involve adding the appropriate properties based on the “light ends” laboratory sample data results. The properties required include the following: l l Percent Weight Yield (wt%) Component Composition by Weight (for ethane, propane, Iso-butane, n-butane, isopentane and n-pentane). 1. Click Setup Properties. 2. The Synthesis Property Selection view list all available refinery property values that you can use to define your Plant Data Group. 3. Refinery properties can be selected from the list and added to the group. Properties may be added only once to each plant group. 4. Scroll down the Available Properties list and highlight Percent weight yield property. 398 v Refinery Assays 5. Click Add to move the property to the Selected Properties list. 6. Select the Component composition by weight property and click Add again. Because this property requires qualifying components, a separate Cut Property view displays where you can select all components you want to include. 7. Expand the Light Ends and C5 Paraffins groups, and then check the boxes in the Selected column for these components: l Ethane l Propane l i-Butane l n-Butane l i-Pentane l n-Pentane v 399 Chapter 5: Oil Characterization Environment 8. Click OK to complete the qualifier selections for this property. 9. Click OK in the Synthesis Property Selection view to complete the property selections and return to the Plant Data Group view. You should have these properties in the grid. 10. Add measured data to the Plant Data Group. Add Measured Data 1. Enter laboratory data from the following table into the corresponding cells on the grid. Leave blank values empty. Press ENTER after entering data in each cell. 400 v Refinery Assays Property Gas C5 Data Percent weight yield (wt%) 0.91 1.58 Ethane Composition (wt%) 0.02 Propane Composition (wt%) 0.18 i-Butane Composition (wt%) 0.18 i-Butane Composition (wt%) 0.53 i-Pentane Composition(wt%) 0.52 i-Pentane Composition(wt%) 0.62 Individual component weight-percent values are taken with respect to the cut and will be normalized to 100% automatically. When you are done entering the measured data, the status bar should display Plant Data Group Ready in green. 2. Click OK to close this view and return to the Refinery Assay Source (Synthesized) view to add a second Plant Data Group. Add Second Plant Data Group 1. Add a second Plant Data Group following steps in Add a Plant Data Group, naming this Plant Data Group, Distillates. 2. Add six cuts following the procedure in Append a Cut. Name and define each cut type as outlined in the table below. v 401 Chapter 5: Oil Characterization Environment Cut Name Cut Type 1 C5-165 Contiguous 2 165-175 Contiguous 3 175-225 Contiguous 4 225-365 Contiguous 5 365-410 Contiguous 6 410-560 Contiguous 3. After creating all six cuts, click Setup Properties and add the required properties to this Plant Data Group following the procedure in Add Properties for these properties and qualifiers. Property Qualifier Percent Weight Yield (wt %) n/a Initial Cut Point n/a Final Cut Point n/a Specific Gravity n/a Sulfur Content (wt %) n/a Nitrogen (wt %) n/a Aromatics Content by Volume (vol %) n/a 402 v Aromatics Content by Weight (wt %) n/a Naphthenes Content by Weight (wt %) n/a Paraffins Content by Weight (wt %) n/a Iso Paraffins Content by Weight (wt %) n/a Research Octane Number 0 Motor Octane Number 0 Cloud Point n/a Pour Point n/a Refinery Assays Property Qualifier Freeze Point n/a Cetane Index ASTM D976-80 n/a Cetane Number D976-80 n/a Diesel Index n/a Aniline Point n/a Refractive Index 20°C (68°F) 70°C (158°F) 4. Select the Stream Types from a drop-down menu. Measured data Property Qualifier Stream Types Viscosity (Kinematic) 20°C (68°F) 40°C (104°F) 60°C (140°F) 100°C(212°F) Conradson Carbon Content (wt %) n/a Stream Type n/a 5. Enter the following measured data for the Distillates in the corresponding cells in the Plant Data Group grid. Leave blank values empty. Press ENTER after entering data in each cell. C5-165 65-175 175225 225365 365410 410560 Percent Weight Yield (wt%) 3.02 14.23 7.00 24.23 7.64 21.67 Initial Cut Point (C) 4.00 65.00 175.00 225.00 365.00 410.00 Final Cut Point (C) 65.00 175.00 225.00 365.00 410.00 560.00 Specific Gravity 0.6488 0.7349 0.7852 0.8244 0.8472 0.8977 Sulfur Content (wt %) 0.0077 0.0113 0.050 0.100 Nitrogen (wt %) Aromatics Content (vol %) 0.150 0.190 0.00006 0.00013 0.0037 0.0250 0.0625 9.00 v 403 Chapter 5: Oil Characterization Environment C5-165 65-175 Aromatics Content (wt %) 2.200 7.700 Naphthenes Content (wt %) 6.1 32.9 Paraffins Content (wt %) 91.7 59.4 Iso Paraffins Content (wt %) 42.1 28.2 Research Octane Number 74.5 39.1 Motor Octane Number 71.9 40.0 Cloud Point 175225 Pour Point 3.0 32.0 0.0 30.0 51.0 97.7 107.9 60.0 Cetane Number D976-80 49.0 Diesel Index 74.4 72.5 Aniline Point 67.2 82.7 1.390 1.415 1.440 Refractive Index (70°C) 1.4520 1.4630 1.4733 Viscosity (Kinematic) 20°C (104°F) 1.650 5.840 Viscosity (Kinematic) 40°C (140°F) 12.330 Viscosity (Kinematic) 60°C (100°F) 27.480 Viscosity (Kinematic) 100°C (212°F) 0.660 Conradson Carbon Content (wt %) Stream Type 404 v 410560 -42.0 Cetane Index ASTM D976 80 Refractive Index (20°C) 365410 12.800 16.500 21.530 -48.0 Freeze Point 225365 1.370 3.140 8.610 0.300 C5s included Refinery Assays When you are done entering the measured data, the status bar should display Plant Data Group Ready in green. 6. Click OK to close this view and return to the Refinery Assay Source (Synthesized) view to add a third group. Add Third Plant Data Group 1. Add a third Plant Data Group following steps in Add a Plant Data Group, naming this Plant Data Group, Residues. 2. Next, add two cuts following the procedure in Append a Cut. Name and define each cut type as outlined in the table below. Cut Name Cut Type 1 560+ Contiguous 2 410+ Overlapping 3. After creating the cuts, click Setup Properties and add the required properties to this Plant Data Group following the procedure in Add Properties for these properties and qualifiers. Property Qualifier(s) Percent Weight Yield (wt %) n/a Initial Cut Point n/a Final Cut Point n/a Specific Gravity n/a Sulfur Content (wt %) n/a Nitrogen (wt %) n/a Pour Point n/a Nickel Content (ppmwt) n/a Sodium Content (ppmwt) n/a Vanadium Content (ppmwt) n/a Viscosity (Kinematic) 70°C (158°F) 100°C (212°F) 150°C (302°F) v 405 Chapter 5: Oil Characterization Environment Property Qualifier(s) Conradson Carbon Content (wt %) n/a Asphaltenes Content (wt%) n/a 4. Enter the measured data for the Residues in the corresponding cells in the Plant Data Group grid. Leave blank values empty. Press ENTER after entering data in each cell. Properties 410+ 560+ Input/Calc Input Input Percent weight yield (wt %) 21.3000 42.9700 Initial cut point (C) 560.000 410.000 Final cut point (C) 850.000 850.000 Specific gravity 0.963800 0.930100 Sulfur content (wt%) 0.320000 0.260000 Nitrogen (wt %) 0.360000 0.240000 Pour point (C) 42.0000 Nickel content (ppmwt) 20.0000 10.0000 Sodium content (ppmwt) 15.0000 6.00000 Vanadium content (ppmwt) 3.00000 1.00000 Viscosity (Kinematic)_70C (cSt) 406 v 170.000 Viscosity (Kinematic)_100C cSt) 764.000 47.0000 Viscosity (Kinematic)_150C (cSt) 97.4000 Conradson carbon content (wt %) 18.9000 9.30000 Alphaltenes content (wt %) 0.570000 0.360000 Refinery Assays When you are done entering the measured data, the status bar should display Plant Data Group Ready in green. 5. Click OK to close this view and return to the Refinery Assay Source (Synthesized) view. 6. With all Plant Data Groups fully defined and data entered, you are ready to synthesize the assay. Synthesize the Assay 1. In the Refinery Assay Source (Synthesized) view, click Synthesize. v 407 Chapter 5: Oil Characterization Environment When the synthesis calculations complete successfully, the status bar changes from yellow to green and displays Synthesis Successful. If errors are encountered during the synthesis operation, they are reported on the Synthesis Messages tab. It is a good idea to review the message information and examine any warnings or errors that may have occurred. For more information, refer to Synthesis Messages. Your synthesized refinery assay may now be used in your flowsheet simulation, saved with the current case or exported to an external file for future use. Black Oil Analysis In some circumstances, you may have very limited compositional data for a fluid. A compositional analysis may not have been measured or the data may have been generated from another application. Black Oil analysis provides a way of constructing a compositional fluid model from limited data. The Black Oil analysis is accessed from the Black Oil tab in the Oil Characterization Environment. From here you can load additional Black Oils into the system from exported Black Oil files (*.xml), or you can create your own Black Oil from laboratory data through synthesis via KBC’s Multiflash technology. Alternatively, you can enter Black Oil source data directly in the stream in the flowsheet environment. 408 v Black Oil Analysis This view shows all Black Oils known to the oil environment.The table describes the buttons that you can use to create, delete, import or export Black Oils: Use this... To do this... View Displays the input data for the Black Oil. Create Adds a new Black Oil and opens the input data form. Delete Removes the Black Oil from the case. Be careful where the Black Oil is used in your simulation: you are not asked to confirm the deletion. Import Shows a drop down allowing a Black import source to be chosen from either a flat XML file or the database. Export Allows you to save a Black Oil to disk so that it can be used in other cases. If you are connected to a database you have the option of storing the Black Oil in your database as well. Clone Create a copy of a Black Oil. Input Data The Black Oil view displays these details: v 409 Chapter 5: Oil Characterization Environment In the Minimum Input for Black Oil Analysis area, enter or select: This column... Enter... Gas Gravity MW of the gas divided by the MW of air (28.964). Select one of the following: Value for the selected option. l l Stock Tank Oil Specific Gravity Dead Oil Density Select one of the following: l l l l Solution GOR Oil Gas Ratio Liquid Gas Ratio Gas Liquid Ratio Value for the selected option: l Solution GOR - gas relative to oil at standard conditions. The following additional information is optional: l l l 410 v Watson K Factor for the oil. (Kw = (Tb)1/3 / SG, where Tb is the boiling point in ºR). Gas Analysis. The gas analysis need not be complete; only the mole percentages of the components named on the form can to be entered, and they need not sum to 100%. Water Cut allows you to add water to the fluid. The amount can be specified as a volume percent of the hydrocarbon liquid phase at standard conditions (60 ºF, 1 atm). SCN Oil Analysis When specifying water cut values: l l The procedure used is approximate but does allow for loss of water to the vapour phase. Adding water does not affect the hydrocarbon fluid characterization although it may affect the subsequent phase equilibria calculations. When you are done, click Synthesize to complete the synthesis. Optionally, click to create a Quick Plot showing the Black Oil properties. Right-click the plot to open the Graph Control view. SCN Oil Analysis The primary information in a PVT lab report is a compositional analysis of the fluid. This analysis is normally carried out by gas chromatography. v 411 Chapter 5: Oil Characterization Environment The gas and liquid from a separator test or bottom-hole sample are analyzed separately and the results are usually recombined to give a reservoir fluid composition. The lighter hydrocarbons such as methane, ethane, propane, etc. are individually identified along with some inorganic compounds such as nitrogen, CO2, and H2S. The analysis for hydrocarbons with more than 6 or 7 carbon atoms is generally reported as single carbon number (SCN) fractions which actually represent compounds in boiling point ranges. For example, a C9 SCN contains all hydrocarbons that boil between the normal boiling point of n--octane + 0.5ºC and the normal boiling point of n nonane + 0.5ºC. The analysis stops at a certain C-number which is reported as a plus fraction. The plus fraction amount contains all the material in the heavy end of the fluid and often represents a substantial proportion of the fluid. The SCN Oil analysis is accessed through the SCN Oil tab of the Oil Characterization Environment. From here you can load additional SCN Oils into the system from exported SCN Oil files (*.xml), or you can create your own SCN Oil from laboratory data through synthesis using KBC’s Multiflash technology. Alternately, you can enter SCN Oil source data directly in the stream in the flowsheet environment. This view displays all SCN Oils known to the oil environment. The table describes the buttons that you can use to create, delete, import or export SCN Oil data. 412 v SCN Oil Analysis Use this... View To.. View the input data for the SCN Oil. The SCN Oil data is defined on the Composition Input and Bulk Properties tabs. Create Add a new SCN Oil and view the input data form. Delete Remove the SCN Oil from the case. Be careful where the SCN Oil is used in your simulation; you are not asked to confirm the deletion. Import Import an SCN source from an XML file or from the Petro-SIM database. Export Export an SCN Oil analysis to an XML file that can be imported into other cases. If you are connected to a database, you can also store the SCN Oil in the database. Clone Create a copy of an SCN Oil. Composition Input Use the Composition Input tab on the SCN Oil Analysis view to enter the SCN Oil's Carbon Numbers and Components. How you enter the fluid composition depends on the information supplied by the PVT Laboratory. You can enter the compositions for any pure components that exists in your fluid package and for single carbon numbers from C6 to C100. Data for a SCN Oil can be entered in one of two ways: Single Fluid v 413 Chapter 5: Oil Characterization Environment If you have a recombined reservoir fluid analysis, select the Single Fluid type. If possible, enter the compositional data in mass units rather than molar units because the GC analysis measures compositions by mass rather than by moles and it is best to use values that are as close as possible to the actual measurements. Liquid + Gas If you only have the separator gas and separator liquid analysis, use the Liquid + Gas type. In this case, it is necessary to enter the correct value of the recombination gas-oil ratio (GOR) as reported by the laboratory. This is entered on the Bulk Properties tab. Often there are several GORs reported that refer to different separators and it is essential to make sure that the appropriate value is used. The gas composition may be entered in either molar or mass units since all the gas phase components have a well-defined molecular weight. The liquid phase composition should be entered in mass units if possible. It is usually best to use the reservoir fluid composition provided by the laboratory because this avoids the complication of recombining the gas and liquid. Entering Composition When entering compositions, select either mass or mole % from Basis drop-down. Different units can be chosen for gas and liquid. However, if you change from mass % to mole % after amounts have been entered, the values are not converted. The same values are retained but in different units. If the Total % does not equal 100%, it is normalized before the characterization is carried out. Although the pseudo-components normally run sequentially in terms of single carbon numbers, it is possible to have data from a non-laboratory source where the SCNs are not sequential. You can still enter these, leaving gaps where appropriate. Bulk Properties Use the Bulk Properties tab on the SCN Oil Analysis view to provide additional information on the molecular weight (MW) and specific gravity (SG) of the fluid. If you have entered a Single Fluid composition, the options are: For the Liquid + Gas input, the options are: 414 v SCN Oil Analysis SG is the specific gravity relative to water at 60ºF and 1 atm. It is also possible to specify the density in API degrees. You can convert from API gravity to SG gravity using the following formula: SG = 141.5/(API + 131.5) The MW and SG of the Stock Tank Oil (STO) can be measured quite reliably and are the best values to enter. The properties of the heaviest SCN (plus fraction) are not normally measured and are obtained by calculation. The values should not be used unless no other information is available. The ‘Single fluid’ MW value is obtained by ‘recombining’ a gas MW and separator liquid MW and is a reasonably reliable value. If none of these values is supplied then during synthesis, Multiflash estimates the values based on the fluid distribution you have supplied. If you have a lean gas or light condensate, that is, where the C6+ fraction is only a minor proportion of the total fluid, we recommend that you allow Petro-SIM to estimate the MW and SG. For heavier condensates with a detailed analysis to C20 or above, it is also probably better not to specify a MW. For oils you should, preferably, enter the MW and SG of the STO as these are usually measured values. Use the Water Cut field to add water to the SCN Oil. The amount can be specified as a volume percent of the hydrocarbon liquid phase at standard conditions (60 ºF, 1 atm). The procedure used is approximate, but does allow for loss of water to the vapour phase. Adding water does not affect the hydrocarbon fluid characterization although it may, of course, affect the subsequent phase equilibrium calculations. v 415 Chapter 6: PFD/Simulation Environment The PFD (Process Flow Diagram) environment, also known as the Simulation Environment, is where you can use the drawing tools to chart the installed streams and operations, flowsheet connectivity, status of objects and more into a graphical representation of the simulation. Petro-SIM is engineered with a multi-level flowsheet architecture tightly integrated within a framework of simulation environments. The intuitive environment framework allows you to focus on the task by providing separate desktops for each environment. Each desktop is specifically suited to the current task by offering only those tools necessary within the selected environment. It is also a natural mechanism for providing peak computational efficiency. The net result is simple and complex flowsheets can be managed in a familiar and consistent manner. The main Simulation Environment can be one of the following types of flowsheets: l l l Main Flowsheet Sub-Flowsheet Column Sub-flowsheet Each flowsheet environment is designed to display a custom desktop and Ribbon toolbar for building and running simulations. You can create flowsheets in any of these views: l l PFD Workbook To enter the PFD simulation environment, click tab. PFD in the Environment group on the Home Petro-SIM uses objects to help you build your simulation: l l Streams Unit operations, which include: l General l Separation, includes Column sub-flowsheet operations v 417 Chapter 6: PFD/Simulation Environment l l Logical Refining In addition, you can use Simulation Tools and Utilities to assist you in defining the simulation case. These tools interact with the process and provide additional information. Every flowsheet (or sub-flowsheet) has its own PFD. l l l Use the multi-flowsheeting architecture to provide clear and concise representations of complex simulations. Use the Navigator and Preview panes to view and navigate the flowsheets and the streams and operations used to represent your process. Use the tools on the PFD tab to help you manage the objects on the flowsheet. See also Working in the PFD Environment for more ways to create and manage your PFD simulation. Main Flowsheet The simulation case main flowsheet serves as the base level or main flowsheet for the entire simulation case and it is where the majority of your work is done, by installing and defining: l l l l Streams Unit operations Columns Sub-flowsheets (optional) A simulation can have only one main flowsheet, which may contain one or more sub-flowsheets or column flowsheets. Sub-Flowsheet A sub-flowsheet is almost identical to the main flowsheet because you can install streams, operations and other sub-flowsheets. While there is only one main flowsheet, each sub-flowsheet has its own corresponding environment. When you are in a sub-flowsheet’s environment, steady state calculations in other areas of the simulation are put on hold until you return to the main flowsheet environment. When you enter the sub-flowsheet’s environment, the Parent icon becomes available, enabling you to quickly switch to its parent flowsheet. The parent flowsheet can be another subflowsheet or the main flowsheet, depending on how the simulation is structured. 418 v Column Flowsheet Accessing different flowsheets by selecting them from the Navigator does not enter that flowsheet’s environment and does not isolate calculations to that flowsheet. To enter and isolate calculations to the flowsheet, right-click the flowsheet, and then select Enter environment. See Multi-Flowsheet Navigation for more details. Sub-flowsheets may contain sub-flowsheets and column flowsheets. Column Flowsheet Similar to a sub-flowsheet, the column flowsheet is where you install and define streams and operations contained in a column such as: l l l l l l Tray sections Condensers Reboilers Side strippers Heat exchangers Pumps Petro-SIM contains ten pre-built column flowsheet templates to help you install a typical type of column and then customize it to your specifications. The column flowsheet desktop environment closely resembles the flowsheet environment. As well, the Column tab becomes available offering you additional tools and options that you can use to design, modify and converge column flowsheets. Column flowsheets do not support sub-flowsheets or other column flowsheets. Working in the PFD Environment Every flowsheet (or sub-flowsheet) has its own PFD. The Navigator and Preview panes provide additional ways to view and navigate the flowsheets and the streams and operations used to represent your process. Use the tools on the PFD tab to help you manage the objects on the flowsheet. l l l l Select Objects Break a Connection Swap Connections Quick Route Mode v 419 Chapter 6: PFD/Simulation Environment l l PFD Colour Schemes PFD HotKeys Select Objects 1. To select objects in the PFD environment, click Select on the ribbon’s PFD tab to filter and select objects by type. 2. In the Select Objects view, highlight the object that you want to locate. Optionally, use the Filter options to narrow down the list of Objects to Select. Use your SHIFT or CTRL keys to select multiple objects. 3. Click OK. The selected objects are highlighted with a red, flashing border on the PFD. 4. Double-click an object to open its property view. Break a Connection The Break Connection function lets you break a connection between a unit operation and stream without deleting the operation or stream. You can break only one connection at a time. 420 v Working in the PFD Environment 1. To break a connection, from the PFD tab, select Break in the Connections group. The cursor changes to a Break cursor. 2. Move the cursor between the stream and unit operation that you want to break the connection. When the cursor is in position, it changes to the Break Ready cursor. 3. Click the stream. The connection breaks leaving the unit operation and stream in place. Swap Connections Use the Swap Connections function to select two streams attached to the same object and swap their nozzle connections. This is useful when streams cross each other. 1. To activate the Swap function, from the PFD tab, select group (or press F on the keyboard). The cursor changes to the Select 1 Swap in the Connections cursor. 2. Hover the cursor over the first stream you want to swap and when the cursor changes to Ready , click to select the first stream. The cursor then changes to the Select 2 cursor. 3. Hover the cursor over the second stream and when the cursor changes to Ready click to select the second stream. , The nozzles on the two streams are swapped. Quick Route Mode To retain the clarity of the PFD, streams should not overlap unit operation icons. When working with large complex flowsheets, each movement of an object causes Petro-SIM to reposition streams so that no unit operation icons are covered. If the PFD is complex, this repositioning can slow down the calculation speed of your case. In Quick Route mode, the relocation and connection of objects is completed without considering the other objects in the flowsheet. For example, if moving a valve, its icon and streams are relocated without repositioning the streams even if one passes over another icon. The Quick Route mode can be enabled while in any mode (Move, Size, or Attach). To activate Quick Route mode from the PFD tab, select Quick Route in the Functions group. v 421 Chapter 6: PFD/Simulation Environment After exiting Quick Route mode, the streams are repositioned automatically so they do not overlap icons. Streams are repositioned only once instead of after relocating each object. PFD Colour Schemes By viewing the colour schemes on the PFD, you can retrieve specific information about your case. The type of information that is available depends on the selected colour scheme. For example, in Default mode, a unit operation can be red, indicating a serious status message associated with the object. The colour red can indicate that the object requires the attachment of a material or energy stream. The benefit of the colour scheme in the PFD is greatly enhanced if the Object Status window is also open. The object colour combined with the information provided in the Object Status window is helpful. Each PFD can have its own distinct colour scheme. Scheme Description LP Utility Display Mode The LP Utility Display Mode can only be initiated from an LP Utility view. Refer to LP Utility for more details. Default Colour Scheme The colour of unit operations and streams is changed to reflect the status of the object. Unit Ops are red if a serious message is in the Object Status window, outlined in yellow if a warning message exists, and completely grey if the object has solved. A Stream icon changes colour after its status message shows OK. The default colours are light blue for unsolved and dark blue for solved. PFD default colours can be changed on the Appearance page in your Session Preferences. Alternate Colour Scheme Streams and unit operation icons are shown as wire frames and the colours can be changed. Right-click an object and click the Change Colour command. The colour palette appears and a new colour can be selected. Select an existing colour or click Define Custom Colours to customize a colour. After a colour is selected, click OK. The new colour for the wire frame appears. Simultaneously change the colour of multiple wire frames by selecting all desired objects. 422 v Working in the PFD Environment Scheme Description Dynamic P/F Specs Temperature The Temperature colour scheme is a Query scheme. Query Colour Scheme The value of a specified variable can be monitored for all material streams. You can select five colours and an associated variable range for each. For the example above, the top colour (Colour 1) appears for material streams that have a temperature greater or equal to 300°C. Colour 2 represents streams ranging from 200 to 300°C, etc. The last colour (Colour 5) is shown for streams that have temperatures below 0°C. Refer to the following sections for information about working with query colour schemes. Change a Colour Scheme The Default Colour Scheme is active when the PFD is first accessed. 1. From the PFD tab, select Colour Scheme in the Options group. 2. In the PFD Colour Schemes view, select the colour scheme from the Current Scheme drop-down list. v 423 Chapter 6: PFD/Simulation Environment When the simulation case is saved, the active colour scheme for each PFD is also stored. You can edit or delete only query colour schemes. A colour scheme is by default only added to the current PFD. But the currently active colour scheme can be copied from the PFD to all other PFDs by selecting Add this Scheme to All PFDs. Adding a Query Colour Scheme To add a colour scheme that tracks a key material stream variable throughout the PFD: 1. Click the Colour Scheme icon in the toolbar. The PFD Colour Schemes view appears. 2. Click the Add a Scheme button. The Select Query Variable view appears. 3. From the list of available variables, select the variable being monitored (some variables require a qualifier such as the Comp Mole Frac variable which requires a component from the list of variable specifics). 4. Click OK. The Edit PFD Colour Scheme view appears. 5. Enter the appropriate values in the variable range fields. 6. To change the colour of the variable range, double-click a colour to access the colour palette. Changes can also be made to the scheme name and to the variable. 7. Click the Close icon to return to the PFD Colour Schemes view with the new colour scheme as the active selection. 8. Click the Close icon to return to the PFD. PFD HotKeys Use To... Arrow Keys Scroll Shift+Arrow Fast Scroll 424 v Working in the PFD Environment Use To... Keys C or . Centre PFD around Cursor Home Center and Zoom on Selected Item PgUp Zoom In PgDn Zoom Out Shift+PgUp Zoom In Fast Shift+PgDn Zoom Out Fast Z Previous View L Mark Label as Movable Shift+P Show Stream Pressures Shift+T Show Stream Temperatures Shift+F Show Stream Molar Flows Shift+M Show Stream Mass Flows Shift+N Show Stream Names Shift+V Show Stream STD Ideal Liquid Volume Flow Shift+I Show Stream Upstream Nozzle Elevation Shift+O Show Stream Downstream Nozzle Elevation A Select All Objects B Toggle Break Connection Mode S Select (Next) Object D Deselect Selected Objects F Select PFD Connections to Flip (e.g. Feeds to a Mixer) H Toggle Drag Mode V or E View or Edit Selected Object X Mirror Icon About X Y Mirror Icon About Y v 425 Chapter 6: PFD/Simulation Environment Use To... 1 Rotate Icon 90 2 Rotate Icon 180 3 Rotate Icon 270 N Rotate back to Normal CTRL with Mouse Quick Attach Mode to Connect or Create Streams DEL Delete Selected Objects F1 General PFD Help F4 View or Hide Object Palette Alt+Click Object Select Object's PFD in Navigator Bar Alt+Up Arrow Select Object's Parent in Navigator Bar Alt+Down Arrow Select Flowsheet Selected in PFD in Navigator Alt+Left Arrow Select Upstream Object(s) Shift+Tab Select Upstream Object(s) Alt+Right Arrow Select Downstream Object(s) Tab Select Downstream Object(s) 426 v Shift+F10 Object Inspect Menu Shift+Click Object Add Object to Existing Selection Chapter 7: Streams Petro-SIM supports two types of streams: l l Material streams are used to simulate the material travelling in and out of the simulation boundaries and passing between unit operations. Energy streams are used to simulate the energy travelling in and out of the simulation boundaries and passing between unit operations. v 427 Chapter 7: Streams Material Streams Material Streams used to simulate the material travelling in and out of the simulation boundaries and passing between unit operations. 1. On the Home tab, click Material. Stream in the Streams group and then choose You can also open the Unit Operations palette (F4) and drag a to the flowsheet. Material Stream A new stream is added to your PFD and the Material Stream property view opens. As you define the stream’s options and parameters, the status bar displays the current status for the material stream: 428 v This colour Means... Green Information is complete. Yellow Optional information is incomplete or missing. The status bar will indicate what information is missing. Red Required information is incomplete or missing. The status bar will indicate what information is missing. Material Streams 2. To define a stream, use one of the following methods: l Copy from another stream - To copy properties or compositions from an existing stream in your flowsheet, click Define from Other Stream. l Select assay - To attach an assay to the stream or synthesize data from another source, click Load Assay . Stream Composition - Manually define the material stream using the stream's associated Worksheet, Composition and Conditions pages. 3. To view a stream's properties, from the Home tab, Streams group, click Properties. 4. To specify a stream's price or see its value, from the Home tab, Streams group, click Pricing. l 5. To attach the stream to a meter, click Send to Meter . 6. To view the properties for the nearest upstream or downstream operation, click the navigation arrows: View Upstream Operation View Downstream Operation If you are working in Dynamics mode and the stream is not connected to an operation at the upstream or downstream end, these navigation arrows open either a Feeder Block or a Product Block. 7. Click the Attachments tab to view or manage the Unit Operations and Utilities for the stream. 8. If you are working in Dynamics mode, select the Dynamics tab to manage the pressure and flow specifications. Define Streams from Another Stream 1. To copy properties or compositions from an existing stream in your flowsheet, click Define from Other Stream. 2. In the Spec Stream As view, select a stream from which you want to copy its properties from the Available Streams list. v 429 Chapter 7: Streams 3. Optionally, select which stream properties and compositions that you want to copy from the Copy Stream Conditions and Flow Basis groups 4. Click OK to copy the selected data to the target stream. 5. You can modify the composition using the tabs and pages in the Material Streams property view. Refer also to Synthesize From Another Source. Synthesize From Another Source You can define a stream's composition by synthesizing data from one of these sources: Stream Composition When you manually define a stream's composition on the Worksheet Composition and Conditions pages, the Load Assay, Synthesize From option shows the stream is synthesized from Stream Composition. If you synthesis from another source, such as Plant Data, this option is no longer visible. Plant Data When you synthesize from Plant Data, the Synthesis Property Selection view displays enabling you to select properties from the Available Properties list to define the stream's composition. 430 v Material Streams Refer to Synthesis Property Selection view for more information. When you synthesis from Plant Data, the Synthesis tab displays the following pages: l l l Plant Data Configuration Diagnostics Meter If the stream is attached to a meter, you can synthesize an assay from the meter operation. For more information about meters, refer to Meter Operation. When you synthesize from a meter, the Synthesis tab displays the following pages: v 431 Chapter 7: Streams l l l Plant Data Configuration Diagnostics Black Oil If you want to synthesize from Black Oils, you can define the Black Oil composition directly in the stream in the Synthesis tab. In the Multiflash Black Oil Analysis area, enter the minimum parameters for the Black Oil that you want to define. For more information, refer also to Black Oil Analysis. The Black Oil definition is only available to this stream. SCN Oil To synthesize the material stream from an SCN oil, select the Synthesis Type from the dropdown list: Single Fluid or Liquid + Gas. Refer to SCN Oil Analysis for details on entering data for an SCN Oil Analysis on these pages. Carbon Numbers Refer to Composition Input for details on entering data on this page. 432 v Material Streams Components Refer to Composition Input for details on entering data on this page. Bulk Properties Refer to Bulk Properties for details on entering data on this page. v 433 Chapter 7: Streams Stream Properties The Stream Properties Manager allows you to create and manage individual properties and property sets that can be applied to material or feed streams in multiple cases. Petro-SIM has three kinds of settings for stream properties. l l l Properties can be determined by the stream type, which is set in Preferences. The properties for each stream type is set by the Knowledge Base. Properties can be added from the Stream Property view. Properties added in this way are only used for that stream. Refer to the Economics (Cost Parameters) page for Material Streams for information about managing property correlations in individual streams. Properties or property sets that apply to all streams can be added from the Property Manager view. The property sets can be defined and saved external to the case, and can be read into any other simulation case. Properties with qualifiers, such as distillation and viscosity, must be created by cloning in the Properties Manager. 1. To open the Stream Property Manager, from the Home tab, select Properties in the Streams group. 434 v Material Streams 2. From the Available Properties list, select the property that you want to view or manage. 3. You can, optionally, modify the Display Name. The Property cannot be modified. 4. In the Qualifiers list, optionally, click the drop-down calculation method cell to select an alternate calculation method for that qualifier. Refer to Refinery Physical Properties for details on the calculation methods. 5. Use the buttons in these groups to manage the stream properties. Use the CTRL or SHIFT keys to select two or more properties. Property Controls Click this... Icon To... Attach to all unlocked streams Attach selected properties to all unlinked streams. Remove from all unlocked streams Remove selected properties from all unlinked streams. v 435 Chapter 7: Streams Click this... Icon To... Clone property and input qualifiers Copy selected properties and their qualifiers. You can only clone property correlations with qualified variable parameters. Delete cloned property Delete cloned properties from all unlinked streams. Property Controls (Global) Click this... Icon To... Remove all properties from unlinked streams Remove all global property correlations from all streams. Add new script property Add a new script property to the property manager. Synchronize all qualifiers/methods with oil manager Set all qualifiers to align with the oil manager. Link all stream properties to stream type Link all stream properties to a stream type. Delete unused cloned properties Delete unused cloned properties from all streams Property Set Controls (Global) The Property Manager allows you to create your own group of properties called a Property Set. You can also select a correlation set and globally apply it to each unlinked stream in the case. Click this 436 v Icon To... View Global Property List Open the Correlation Set Picker where you can select the correlation set you want to apply to all the streams. By default, only the standard set is available from which to make selections. Remove Global Property Set Remove the active selected global correlation set from all streams. This does not remove any local correlation Material Streams Click this Icon To... set, even if the global correlation set is identical to the local correlation set. Active Set The status bar indicates the status of the active selected global correlation set. l l l Red - No global correlation set is selected for the streams. Green - A global correlation set is selected for the streams. Yellow - A global correlation set is selected for the streams, but the selected global correlation set is modified. Global correlation sets have the same name as the local correlation set. Stream Prices The Stream Prices tool provides a means of setting a feed or product material stream price based on the flow, a fixed value, component flows or a property. You can define any number of pricing bases within a case using this information as part of an overall economics utility by linking a stream to one of these pre-defined bases. 1. To open the Stream Prices view, from the Home tab, select Pricing in the Streams group. v 437 Chapter 7: Streams 2. Click Add to add a new Property-Based Price object. 3. Define the stream pricing properties on the following pages. Property Use the Property page to add a property-based price to your simulation case. The stream value is a function of the base price together with property-based adjustments to the price. Set adjustments for any number of properties as a delta cost per unit flow multiplied by the stream property value minus the base property value. For example, you can value an FCC Naphtha with a base value of 30 $/bbl at a RON of 91 and an adjustment of ±3$/bbl for each RON away from the base. The total value is then: Total Value = Flow * (30 + (RON − RONBase ) * 3) 1. In the Selected Price area, enter a Name for the Property-Based Price. 2. Select the flow basis from the Price Basis drop-down list: Molar Flow, Mass Flow, Volume Flow, Fixed , or FOE. 3. In the Property Adjustments table, click Add… to select one or more stream properties that the price is based on (for example, SG, RON, MON, etc.). 4. Set the corresponding Base Value on which to apply the base price and a Premium cost when the base value either exceeds or is below the base value of the property. 438 v Material Streams 5. Optionally, check the Use Stream Cost Parameters option to calculate the base price using the settings on the Material stream’s Economics page. This allows you to configure a standard penalty or premium to any number of streams with different base prices. 6. Otherwise, enter the base pricing information in the Base Parameters matrix on the Stream Prices view. Composition Use the Composition page to provide prices for the individual component flows in a stream, where the total stream value is the sum of the product of component flow and price. Total Value = ΣComponent Flow * Price v 439 Chapter 7: Streams 1. On the Composition page, click Add to add a new Composition-Based Price object. 2. Enter a Name and select a Flow Basis from the drop-down list: Molar, Mass, or Volume. 3. In the Components area, click Add… to select one or more stream components on which to base the price. 4. Enter the price in the Price field opposite the component. Tiered Flow Tiered Flow pricing allows you to calculate stream values when the price received or paid changes depending on the stream’s flow rate. 1. On the Tiered Flow page, click Add to add a new Tiered Flow Price object. 440 v Material Streams 2. Enter a Name and select a flow rate from the Price Basis drop-down list: Molar Flow, Mass Flow,Volume Flow, or FOE. 3. In the Tiers area, click Add... to add a new flow and enter a corresponding Flow Limit and Price. 4. In the Price Type group select: l Marginal - the Price column represents the price of the amount produced in each tier. In this case if the Naphtha flow rate is 4500 bbl/d, the total value would be $30x2000 + $25x1500 + $20x1000. l Average- the Price column for each tier represents the average price for the entire stream flow. In this example, the total value would be $20x4500 bbl/d. Composite Use the Composite page to set the price based on a combination of two or more Property, Composition, and Tiered Flow based prices. 1. On the Composite page, click Add to add a new Composite Price object. 2. Enter a Name. 3. From the Available Stream Prices list, select the stream prices that make up the v 441 Chapter 7: Streams composite price and move it to the Selected Stream Prices list. Applying Stream Pricing to Streams When a new price option is added in the Stream Price tool, you can use one of two methods to apply the stream pricing to the stream: From the Economics page Configure material streams to use the pricing to arrive at a Stream Value. 1. Open the Properties page for the stream that you want to configure, and from the Economics page on the Worksheet tab select a Pricing Method from the drop down list. The Stream Value is then calculated based on the pricing set in the Stream Prices tool. 442 v Material Streams The Stream Value can be imported into spreadsheets and used for other calculations. From the Properties page When a new price option is added in the Stream Price tool, a corresponding stream property is created. This means that you can also view a stream’s value by adding it to the Properties page. 1. Open the Properties page for the stream that you want to configure, and from the Properties page, click . 2. In the Property Picker view, expand the Cost Based on Flow property from the Available Properties list and then select the stream pricing that you want to use. v 443 Chapter 7: Streams The Stream Price is appended as a property to the stream's Properties. The stream property can be imported into spreadsheets and used for other calculations. Attach an Assay 1. To attach an assay to the stream from the Material Stream Properties view, click Assay. 444 v Load Material Streams 2. From the pop-up menu, select one of the following options to load an assay: Select this… To do this… Load From Oil Manager Select a refinery assay, Black Oil or SCN Oil defined in your current simulation. CADB Import Open the Assay Selection view where you can select one or more assays to import from CADB assay files. You must have a CADB file installed to use this option. Petro-SIM Database Import Opens the Assay Selection view where you can select one or more assays to import from a Petro-SIM Database. Synthesize From Select the synthesis method from : l l l l Plant Data – in the Synthesis Property Selection view, select the properties from which the assay will be synthesized. Meter – if the stream is attached to a meter, select this option to synthesize an assay from the meter operation. Black Oil - if you want to define a Black Oil, select this option to open the Multiflash Black Oil Analysis view. SCN Oil - if you have an SCN assay defined in the simulation, select this option to import the data into the Synthesis tab. If you manually entered the Composition, you may also see Stream Composition as the checked option to indicate that the stream is defined on the Composition page. Remove Assay Remove the assay from the stream. This option is available only if the material stream is loaded with an assay. Synthesize from Plant Data When you synthesize from Plant Data, the Synthesis Property Selection view displays enabling you to select properties from the Available Properties list to define the stream's v 445 Chapter 7: Streams composition. Refer to the Refinery Assay Synthesis Tutorial for details about adding properties in the Synthesis Property Selection view. When you synthesis from Plant Data, the Synthesis tab displays the following pages: l l l Plant Data Configuration Diagnostics Synthesize from Meter If the stream is attached to a meter, you can synthesize an assay from the meter operation. For more information about meters, refer to Meter Operation. When you synthesis from a meter, the Synthesis tab displays the following pages: 446 v Material Streams l l l Plant Data Configuration Diagnostics Synthesize from Black Oil If you want to synthesize from Black Oils, you can define the Black Oil composition directly in the stream in the Synthesis tab. In the Multiflash Black Oil Analysis area, enter the minimum parameters for the Black Oil that you want to define. For more information, refer also to Black Oil Analysis. The Black Oil definition is only available to this stream. Synthesize from SCN Oil To synthesize the material stream from an SCN oil, select the Synthesis Type from the dropdown list: Single Fluid or Liquid + Gas. Refer to SCN Oil Analysis for details on entering data for an SCN Oil Analysis on these pages. Carbon Numbers Refer to Composition Input for details on entering data on this page. v 447 Chapter 7: Streams Components Refer to Composition Input for details on entering data on this page. Bulk Properties Refer to Bulk Properties for details on entering data on this page. 448 v Material Streams Performing Flash Calculations Petro-SIM uses degrees of freedom in combination with built-in intelligence to automatically perform flash calculations. For a stream to flash, specify the following information (either from your specifications or as a result of other flowsheet calculations): l l Composition Assay, if the stream is a Refinery stream. To enable Petro-SIM to automatically perform a flash calculation, you must specify at least two known flash type variables. Once a stream has flashed, intensive properties for the stream are calculated. You can examine these properties in the Properties page. To calculate other properties, such as Heat Flow, a flow rate is required. Refinery properties require an assay. Displaying Phases The stream parameters can be specified on the Conditions page or in the Workbook view. Changes in one area are reflected throughout the flowsheet. While the Workbook displays the bulk conditions of the stream, the Conditions page, Properties page and Compositions page also show the values for the individual phase conditions. Petro-SIM can display up to five different phases. v 449 Chapter 7: Streams l l l l l l l Overall Vapour Liquid Aqueous Second Liquid Solid Mixed Liquid – Petro-SIM does calculate mixed liquid properties, but it does not display the mixed liquid phases in a stream. The Mixed Liquid phase combines the Liquid phases of all components in a specified stream and calculates all liquid phase properties for the resulting fluid. The Mixed Liquid phase does not add its composition or molar flow to the stream it is derived from; it's another representation of existing liquid components. To view the hidden phase properties, expand the width of the default stream view by dragging the edge of the view. In the example below, the Vapour and Liquid phase properties appear beside the Overall stream properties. If there was another liquid phase, it would be shown as well. Instead of expanding the view, use the horizontal scroll bar to view the hidden phase properties. When you are viewing a stream property view in the column sub-flowsheet, there is an additional Create Column Stream Spec button on the Conditions page. For more information, refer to Add Column Specifications. 450 v Material Streams Worksheet The Worksheet tab on the Material Streams property view consists of the following stream property pages: l l l l l l l l l l Conditions Properties Composition K Value User Variables Economics Bulk Properties Notes Time Series Time Results Conditions Use the Conditions page on the Worksheet tab to modify or view the names and current values for the following condition parameters: l l l l l l l l l l l l l l Stream Name Vapour/Phase Fraction - If you specify a Vapour Fraction of 0 or 1, the stream is assumed to be at the bubble point or dew point, respectively. You can also specify vapour fractions between 0 and 1. Temperature Pressure Molar Flow - You must enter either a molar or mass flow. Mass Flow Std Ideal Liq Vol Flow Molar Enthalpy Molar Entropy Heat Flow Liq Vol Flow @ Std Cond Fluid Package Stream type - Default stream types are set in Preferences. Short name - The short name is used in the LP Utility. v 451 Chapter 7: Streams Properties Use the Properties page on the Worksheet tab to modify the stream properties determined by the stream type shown on the Conditions page. Use the Property Controls tools to view and modify the properties for the selected stream. Name 452 v Icon Description View Property Set List Select a correlation set to view the property set list. Append New Property Add a new property to the end of the list. Move Selected Property Down Move the selected property one row down the list. Move Selected Property Up Move the selected property one row up the list. Sort Ascending Sort the properties in ascending alphabetic order. Remove Selected Property Remove the selected property correlation from the table. Remove All Properties Remove all the property correlations from the table and the correlation set name from the stream. Save Property Set to File Save a set of property correlations. Material Streams Name Icon Description Link Properties Displayed to Stream Type Click to display only those properties related to the stream type. View and Edit Selected Property View and edit parameters and status of the selected property from the table. View Stream Plot View all property plots for the selected stream. Use the Property Manager to manipulate the properties page for all streams in the PFD. View a Property Set List 1. Click (View Property Set List icon). 2. Use the or symbols to expand or collapse the properties in the set. 3. In the Property Set Picker view, select the property set you want from the view. 4. Click the Apply button. The properties are displayed at the bottom of the list in the Properties view. v 453 Chapter 7: Streams 5. Expand the view or use the scroll bar to view any property phase values. Hover your cursor over a property in the property list to display the property’s calculation methods. Append New Property 1. To append a new property to the properties list, click . 2. In the Property Picker view, select a property that you want to add from the Available Properties list. Use the arrows next to the property name to expand or collapse the properties, if necessary. 454 v Material Streams Use SHIFT or CRTL key to select multiple properties. 3. Click Apply to append the selected property to the end of the stream list. When you add a new property, the link to the stream type properties breaks and all properties remain. 4. Optionally, select a property and then select a different material stream to append the property. a. In the Select Material Stream view, select the stream that you want the property appended to from the list. b. Click Close to return to the Properties page 5. When you are done adding property correlations, click Close to return to the Properties page. Remove Properties 1. Select the property you want to remove in the table. 2. To remove a single property correlation, select the property and then click property correlation is immediately removed from the list. 3. To remove all property correlations from the list, click . The . You are not asked to confirm the removal and you cannot undo this action. If you make a mistake, you will need to add the property in manually. Save Property Set to File When you are done adding or removing property correlations from the list, you can save the properties to a Correlation Set Name. v 455 Chapter 7: Streams 1. In the Material Properties Stream view, click . 2. In the Save Correlation Set Name view, confirm the name that Petro-SIM automatically generated based on the stream name, or enter a new name in the Set Name field. 3. Click Save to save the property list. You can add the saved correlation set to other streams from the Property Set Picker view. View and Edit Properties 1. In the Material Stream Property view, select a property and then click . 2. In the View and Edit Selected Property view, use the Property Control tools to modify the selected property. Use this… To… Attach the selected property to all unlocked streams. Remove the selected property from all unlocked streams. 456 v Material Streams Use this… To… Clone the selected property and input qualifiers. Delete selected cloned property/properties from unlocked streams. 3. In the Qualifiers group, view or edit the parameters used to calculate the property correlation. 4. When you are done making changes to the property or property qualifiers, close the view to return to the Properties page of the Material Stream Property view. View Stream Plots 1. To view the correlation plots for all properties that can be plotted for the stream, click . 2. In the Property Plots view, select the properties that you want to plot and view on the v 457 Chapter 7: Streams graph. Only properties that can be plotted on the graph are available in the list. Refer to Plot Utility for more information about plotting properties in this view. Composition The default colour for specified stream values is blue, and black for those calculated by Petro-SIM. You cannot edit the compositions for a stream calculated by Petro-SIM. The Edit button on the Composition page is greyed out. Refer also to Viewing Hypothetical Components. 1. On the Composition page, click Edit. OR Type a value in a component cell and press ENTER. 2. In the Input Composition view, select a Composition Basis and enter the composition value for each component. 458 v Material Streams 3. From the Composition Basis group, select the radio button that corresponds to the basis for your stream. 4. In the list of available components, specify the composition of each component in the stream. 5. Select one of these options from the Composition Controls group: Button Action Erase Clears all compositions. Normalize Use to enter any value for fractional compositions and have Petro-SIM normalize the values such that the total equals 1. This option is useful when many components are available, but you want to specify compositions for only a few. After you enter the compositions, click Normalize and Petro-SIM ensures the Total is 1.0, while also specifying any <empty> compositions as zero. If compositions are left as <empty>, Petro-SIM cannot perform the flash calculation on the stream. Normalize does not apply to flow compositional bases, since there is no restriction on the total flow rate. 6. When you're done modifying the input composition, click OK to return to the Material Stream Property view. The figure below shows an example where the mole fractions for each component in the overall vapour and liquid phases. v 459 Chapter 7: Streams 7. Use the tools in the Refinery Assay group to modify the streams with assays. Name Icon Description Quick Plot Opens the Refinery Assay Property Quick Plot view in which you can plot the assay properties on a graph. Refer to Plot Utility for more information. Load a Refinery Assay into Stream Select an option to load an assay into the stream. Save Refinery Assay to Oil Manager Opens the Save Assay view. Select the Export Type: 460 v Material Streams Name Icon Description l l l Plant Data – exports available synthesis data to the Oil Environment. Synthesis Cuts – exports the stream’s assay as a set of contiguous synthesis cuts calculating properties for the selected number of cuts by dividing the stream into a series of equal cuts. Use this if you want to move the assay between fluid packages within the same case or different cases. Set the Number of cuts using the spinner controls. Property Slate – exports the stream’s assay as a matrix of properties by component, preserving the full detail of the assay. Use this if you want to reuse the assay within the same fluid package. Check Overwrite existing assay if you want the data to overwrite an existing saved assay. Remove assay Removes the attached assay from the stream. 8. Optionally, click View Properties to view the properties for the stream. Alternatively, right-click the banner of the Material Stream Property view and select Send to Assay Browser to view the properties in the Assay Browser. 9. To view the composition in a different basis, select another basis from the Basis dropdown list. l Select View Extended Composition to show only the overlaid synthesis components. The composition matrix no longer shows the fluid package v 461 Chapter 7: Streams components. l Expand or collapse the property constituents that you see by clicking + and – next to the property name. Viewing Hypothetical Components Some hypothetical components may contain embedded naphtha components. To see which naphtha components are contained in a hypo, right-click the hypo’s composition value and choose from one of the Trace Extended Components options. The various constituents of the hypo are displayed in the Trace Window. K Value The K Value page displays the K values or distribution coefficients for each component in the stream. 462 v Material Streams A distribution coefficient is a ratio between the mole fraction of component i in the vapour phase and the mole fraction of component i in the liquid phase: y Ki = i x i where: K = distribution coefficient i y = mole fraction of component i in the vapour phase i x = mole fraction of component i in the liquid phase i Economics (Cost Parameters) Use the Economics page to enter cost parameter information for the stream. v 463 Chapter 7: Streams 1. From the Pricing Method drop-down list, select a pricing method: l Cost Based on Flow - complete the remaining steps in this procedure to define the Stream Value. l Custom price defined by the Stream Price tool - the Stream Value is automatically calculated based on the values defined in the Stream Price tool. 2. If you selected Cost Based on Flow, choose the basis of the price in the Price Basis group. Select… Results in… Molar Flow, The stream value is calculated by using: Mass Flow , or Value = Flow x Price Liq. Volume Flow Fuel Oil The stream value is calculated by using: Value = Mass Flow (Dry) x Price x Mass Lower Heating Value (Dry) / Fuel Oil Calorific Value To specify the Fuel Oil Calorific Value, open the Properties Manager. Select the Cost Based On Flow property, and then enter a value in the Fuel Oil CV cell of the Qualifiers matrix. Heating Value The stream value is calculated by using: Value = Mass Flow (Dry) x Mass Lower Heating Value (Dry) xPrice Fixed The stream value calculates the cost on the fixed value that you enter in the Price field. 3. To select the stream’s Pricing Method, choose a method from Pricing Method drop-down list. The result is displayed in the Stream Value field. 4. To add a new pricing method, click Pricing in the Streams group on the Home tab. Refer to Stream Pricing and Applying Stream Pricing Values to Streams for details. Bulk Properties The Bulk Properties page allows you to view the bulk stream properties that are imported with the assay in the stream. Refer to Refinery Assay for more details. 464 v Material Streams Use the tools at the top of the view to manage the properties. Name Icon Description Edit the Selected User Variable Opens the Edit view where you can modify or attach a script to the property. Sort Alphabetically Sorts the properties in the list alphabetically. Sort by Execution Order Sorts the properties in the list by the order in which they should be executed. Move Down Moves the property down one position. Move Up Moves the property up one position. Time Series Use the Time Series page to enter values for stream variables that vary by date. 1. From the Worksheet tab in the Material Stream Property view , click Time Series. v 465 Chapter 7: Streams Time series data is stored inside a scenario utility. 2. To add data to the Time Series grid, click the drop-down arrow in the Scenario field and select one of the following options: 466 v Select this… To… <Create New>” Create a new scenario utility to contain the data. <none> Not see data from any scenario. This does NOT delete the data in the scenario utility. Other listed scenarios View data for the stream stored in that scenario. Typically, select an existing utility if you have data for multiple streams at the same dates. Material Streams Select this… To… Multiple scenario utilities may exist that contain data for the same stream. A utility can hold data for any number of objects. 3. Optionally, to view a selected scenario utility, click the data for the selected scenario. . The Scenarios view displays You can enter data for a stream in multiple scenario utilities, but you must ensure there are no conflicts or unintended overlaps. 4. When you create a new scenario or select an existing one, a set of variables that correspond to what is specified inside the stream are automatically added to the table. For each state in the times series: 5. State automatically displays a name for each time series column when you select the Activation field. 6. Click the drop-down arrow in the Activation field and select the activation type: Activation Description Type Reset When the date is reset or a time run is started, this column has values to be applied initially. Manual The values apply when you click Apply State from the Scenarios utility. Date The values apply from a specific date onwards. Date, When you have multiple columns with this activation and the date lies interpolated between those for the columns, the values are interpolated based on date. Disabled The column is ignored, not used. User Logic The column of values is activated based on a logic expression. For this, click to view the Scenarios utility and then access the user logic settings. 7. Enter a date associated with the column in the Date row. To edit the date when a date cell is selected, press F2. The default format for the date depends on your local windows regional settings. To change the date display format, right-click the cell and select Change Date and Time Format. 8. Enter values for each variable in the column for the specified date. l The values for each variable are plotted on the graph enabling you to see if they trend correctly or if some values are in error. v 467 Chapter 7: Streams l l If the curve has many trends, click the curve to activate the corresponding Y axis on the curve. Optionally, to hide or show variables on the graph, select , Input Plot, and then choose a variable name to check (show) or uncheck (hide) it from the graph. 9. To add a new variable to the time series, click , select Add Variables and then select the variables you want to add from the Variable Navigator. You can also have composition values inside the table. Apply the Time Series 1. From the Ribbon toolbar, click the Time Series tab. 2. Select Setup and then choose Date. 3. Change the current simulation date. When that current date is changed, or when you run through a date window, values on the Time Series page in the stream are applied. Consider the following example: The values for the temperature and black oil gas gravity change with the date. When the date is changed, values from this table are applied and the stream solves using the new values. Time Results If a scenario utility has time series data for a stream, it automatically creates a strip chart for the stream. A strip chart records values for variables when a date run is executed; otherwise the chart is empty. The chart shows the actual values as they were at a particular point in time. 468 v Material Streams Execute a date run 1. On the Time Series tab, click Setup and then choose Date. 2. In the Date Settings view, on the Date tab, select the Start Date and End Date and then click Run. The results display in the stream’s Time Results page strip chart which takes on the same name as the stream. The Time Results view may take a few minutes to display all the data. 3. Optionally, click History to view the numerical values in a grid. View all strip charts in a case 1. Press CTRL+D to open the Databook. 2. In the Databook view, select the Active check box next to the objects you want to view. 3. Click the Strip Chart button. 4. Optionally, to open a view that contains numerical historical values that correspond to the strip charts, click the Historical button. For more details, refer to the Time Series tool and Scenarios utility. v 469 Chapter 7: Streams Synthesis The Synthesis tab on the Material Streams property view is available when the stream’s assay is being synthesized from one of the following data types. The information that is displayed on this tab depends on the synthesis method employed. l l l l l Stream Composition - the Plant Data, Configuration and Diagnostics pages display the stream's synthesis properties. Plant Data – - the Plant Data, Configuration and Diagnostics pages display the stream's synthesis properties. Meter – - the Plant Data, Configuration and Diagnostics pages display the stream's synthesis properties. Black Oil – the Synthesis tab enables the black oil properties on the Multiflash Black Oil Analysis view. Refer to Black Oil Analysis for details on defining the properties. SCN Oil – the Synthesis tab includes the SCN Oil analysis pages where you can define the properties. Refer to SCN Oil Analysis for details on defining the properties. Plant Data Use the Plant Data page on the Synthesis tab to enter input plant data values. If you stretch the stream property view or scroll horizontally, the calculated synthesis results are also available. The Data Source property indicates the stream name and whether the stream is synthesized from another source . If the stream assay is being synthesized from composition, the input properties cannot be edited. In this case, the property list will be automatically rebuilt and populated with values corresponding to the composition specification. 470 v Material Streams Configuration Use the Configuration page on the Synthesis tab to add or remove properties and configure how the data is updated. To specify which properties must have input values before synthesis is attempted, check the cells in the Required column next to the property in the Properties list. Use this... To... Select Properties Add or remove properties. In the Synthesis Property Selection view, select additional properties from the Available Properties list. Check Available Synchronize this list with input properties that are already specified. Lock Properties Lock the properties list from being updated. Automatic from stream comp. Synthesize from composition or plant data. Use oil manager synthesis parameters and methods Use the Oil Manager’s synthesis settings. De-select to override the Oil Manager's synthesis settings. This enables three new pages on the Synthesis tab: l l l Parameters Synth. Methods Phys. Methods v 471 Chapter 7: Streams Parameters The Parameters page is only available when you synthesize from Plant Data and choose to override the Oil Manager synthesis settings. Use this page to modify the synthesis parameters. Click Reset All Synthesis Parameters to revert your changes to the Oil Manager settings. Synth. Methods The Synth. Methods page is only available when you synthesize from Plant Data and choose to override the Oil Manager synthesis settings. Use this page to specify which synthesis methods should be used when generating the stream assay. 472 v Material Streams Click Reset All Synthesis Methods to revert your changes to the Oil Manager settings. Phys. Methods The Phys. Methods page is only available when you synthesize from Plant Data and choose to override the Oil Manager synthesis settings. Use this page to specify which physical property methods should be used when generating the stream assay. Click Reset All Physical Property Methods to revert your changes to the Oil Manager settings. v 473 Chapter 7: Streams Diagnostics The diagnostics generated by synthesis are presented on this page. It provides details of the synthesis and can be useful in troubleshooting problems. Attachments Unit Ops Use the Unit Ops page on the Material Stream property view to view the names and types of unit operations and logical operations to which the stream is attached. 474 v Material Streams The view shows: l l Attached Unit Operations - displays the unit operations from which the stream is a product and the unit operations s to which the stream is a feed. Logical Ops - displays the logical operations to which the stream is connected. Double-click a unit or logical operation to view its property view. Utilities The Utilities page lets you view and manipulate the utilities attached to the stream. v 475 Chapter 7: Streams To add a utility to the stream, click Create and select the utility that you want to attach. To view the utility, select it and then click View. Refer to Utilities for more information about Petro-SIM utilities. 476 v Energy Streams Energy Streams Energy streams are used to simulate the energy travelling in and out of the simulation boundaries and passing between unit operations. Create an energy stream in one of the following ways: 1. On the Home tab, click Energy. Stream in the Streams group and then choose You can also open the Unit Operations palette (F4) and drag an to the flowsheet. Energy Stream A new stream is added to your PFD and the Energy Stream property view opens The Energy Stream property view contains tabs used to define stream parameters and view objects to which the stream is attached. These tabs are: l l l l Stream Unit Ops Strip Chart Cost Factors 2. To view the properties for the nearest upstream or downstream operation, click the navigation arrows: View Upstream Operation View Downstream Operation v 477 Chapter 7: Streams If there is no upstream or downstream connection on the stream, these icons are not active. Stream Use the Stream tab on the Energy Stream property view to specify the Stream Name and Heat Flow for the stream. When converting energy stream to a material stream, all material stream properties are unspecified, except for the stream name Unit Ops The Unit Ops tab Energy Stream property view displays the names and types of all objects to which the energy stream is attached. Both unit operations and logicals are listed. The Unit Ops tab either shows a unit operation in the Product From cell or in the Feed To cell, depending on whether the energy stream receives or provides energy respectively. 478 v Energy Streams Double-click either the Product From or Feed To cell to open the property view of the operation attached to the stream. Strip Chart Use the Strip Chart tab on the Energy Stream property view to create a strip chart displaying the variables associated with the energy stream. To modify the strip chart properties, right-click the strip chart background and select Graph Control to open the Strip Chart Configuration view. v 479 Chapter 7: Streams Cost Factors Use the Cost Factors tab on the Energy Streams property view to define a cost factor for the stream based on either the Heat Flow or an Absolute cost. 480 v Synthesis Transition Synthesis Transition Synthesis transition is an advanced method to transfer stream data from a feed stream to a product stream with a different fluid package. The synthesis transition generates plant data cuts from the feed stream, and then synthesizes the product stream from these cuts. The synthesis transition can be used in the stream cutter, sub-flowsheet, and column operations. The Synthesis Transition view contains these pages: l l l l l l l Configuration Comp. Groups Plant Data Diagnostics Parameters Synth. Methods Phys. Methods Configuration The Synthesis Transition Configuration page allows you to specify how many plant data cuts will be generated from the feed stream. In addition to the specified number of cuts, two extra cuts will be generated. The first extra cut is reserved for composition data, typically light ends. The second additional cut is reserved for extended compositions (e.g., PONA). By default, the transition will try to choose cuts that are evenly spaced in terms of temperature, using the NBPs of hypothetical components in the feed stream as potential cut points. As well, the transition will only generate cuts across the boiling range of the feed stream. If you prefer the transition to choose cuts with more similar yields, choose Equalize by yield from the Cut point selection group. v 481 Chapter 7: Streams These cut points are updated each time the transition solves, unless you click the Lock cut points box. Alternatively, you can specify (and lock) cuts points by typing override values in the Cut points matrix. To generate cut points that span the entire set of hypos in the feed fluid package, click the Generate Cut Points Spanning Entire Slate button. If you have specified your own cut points, you may notice that the Actual Cut Points column does not match exactly the Specified Cut Points column. This is due to the fact that the transition will generate cut points using the NBP of the hypo component closest to each specified cut point. As well, if the boiling range of the feed stream falls into a subset of the specified cuts, the transition will only generate cuts that fall into this range. In many cases, the feed stream may be completely defined by its light ends and extended compositions (i.e., the sum is 100%). In such situations, the transition can avoid a full synthesis and synthesize with pure components only. To enable this feature check the Synthesize from only composition box and configure the tolerance. If the option is turned on and the composition sum is greater than the tolerance, the contiguous cuts will be ignored, and synthesis will be performed on only the light ends and naphtha cuts. Some assays may have trace amounts of components that you want to filter out. You can do this using the Minimum composition value option. Any component that has a composition below this value will be excluded from synthesis. 482 v Synthesis Transition By default, the synthesis transition will generate compositional and yield data on a volume basis. If you prefer to work on a mass basis, select Weight from the Composition Basis group. When the transition is synthesizing into a stream with a fluid package with more pure components than the inlet, it is assumed that you want to completely distribute all extended components in the feed to pure components in the product. If this is not possible because the product fluid package is not detailed enough, you will be warned. If you want to disable this warning, click the Warn when outlet hypo composition is greater than box. Alternatively, you can change the warning threshold. The Naphtha Estimation options control how naphtha components in the Cyclopentane to C11 PONA range get handled. There are three options: l l l Default Action - component values will be calculated from the feed stream. Estimate from source assay where missing - applies when no values can be calculated from the feed stream and causes component values to be estimated from the pseudocomponent PONA properties. The estimation method aims to preserve the pseudocomponent composition and property profile as much as possible and will distribute among available isomers on an equi-volume basis. For example, if a pseudocomponent has an aromatics content of 5 lv% and there are 2 possible aromatics species within the boiling range of the pseudocomponent, then each species will be allocated a composition of 2.5 lv% of the pseudocomponent volume. Always estimate from source assay - always ignores any values that can be calculated and estimates from pseudocomponent PONA properties as above. The estimation options can provide you with a useful alternative to the standard assay synthesis estimation methods in situations where you know the pseudocomponent properties are consistent with detailed breakdowns without the detailed breakdown itself being available. This can happen if you introduce feed streams from external systems. Comp. Groups The Synthesis Transition Comp. Groups page can be used to generate detailed PONA compositions, if they are not available in the feed stream. For example, if your feed stream had only a bulk value for C8 Aromatics, you can specify how this composition is distributed across EBenzene and the Xylenes. The volume fraction of the sub-component can be specified in the Distribution column, and the transition will distribute the bulk composition accordingly. Note that the fractions do not need to sum up to 1.0, any remaining composition will be allocated to the bulk composition. v 483 Chapter 7: Streams Plant Data The Synthesis Transition Plant Data page shows the input cut data generated from the feed stream. If the Show input and calculated values together box is checked it will also show the calculated synthesis results. If not, these results are found on the Calculated sub-page. If the transition calculated using composition data only, the raw input cut data can be found on the Raw sub-page. Clicking the Export to Oil Manager button will create a new assay in the oil manager that is configured with the raw plant data cuts. Diagnostics The Synthesis Transition Diagnostics page displays the diagnostics generated when synthesizing the product stream. It can provide useful information when troubleshooting synthesis errors. Parameters The Synthesis Transition Parameters page is available when the Use oil manager settings box is not checked. You can specify which synthesis parameters the transition uses. 484 v Synthesis Transition Synth. Methods The Synthesis Transition Synth. Methods page is used to specify which synthesis methods the transition uses. Phys. Methods Page The Synthesis Transition Phys. Methods page is used to specify which physical property methods the transition uses. v 485 Chapter 7: Streams 486 v Chapter 8: General Unit Operations From the Home tab, click General on the Operations group to view the palette (or press F4). Petro-SIM offers these General unit operations: l l l l l l l l l l l l l l l l l l l l l l l l Separator 3-Phase Separator Tank Mixer Tee Heater Cooler Multistream Exchanger Heat Exchanger Air Cooler Pump Expander Compressor Valve Relief Valve Pipe Segment Continuously Stirred Tank Reactor (CSTR) Plug Flow Reactor Gibbs Reactor Equilibrium Reactor Conversion Reactor Gas Turbine Burner Steam Generator v 487 Chapter 8: General Unit Operations l l l l l l l l l l 488 v Steam Jet Ejector Steam Use Deaerator Desuperheater Steam Header Hydraulic Turbine Steam TurboGen Basic Boiler Turbine Group Steam Gen Group Separator, 3-Phase Separator, and Tank Separator, 3-Phase Separator, and Tank The Separator, 3-Phase Separator, and Tank unit operations are similar and are described as one vessel unit operation type. The key differences between these operations are the stream connections (related to the feed separation). All three of these vessel unit operations can also be used as reactors. Alternatively, you may select one of the other reactors from the Unit Operations palette. 1. To add a Separator, 3 -Phase Separator, or Tank to your simulation from the Home tab, open the Operations, General palette (or press F4). 2. Double-click the icon for the vessel operation (or click and drag it to the flowsheet): Select... To add... Vessel Description Separator Multiple feeds, one vapour and one liquid product stream. The Separator divides the vessel contents into its constituent vapour and liquid phases. 3 -Phase Separator Multiple feeds, one vapour and two liquid product streams. The 3-Phase Separator operation divides the vessel contents into its constituent vapour, light liquid and heavy liquid phases. Tank Multiple feeds, one liquid and one vapour product stream. The Tank is generally used to simulate liquid surge vessels. The selected unit operation is added to the active flowsheet. v 489 Chapter 8: General Unit Operations Separator Property View 3 -Phase Separator Property View 490 v Separator, 3-Phase Separator, and Tank Tank Property View 3. Enter the properties for the unit operation in these tabs: l Design l Reactions l Rating l Worksheet l Dynamics- This tab is available only when working in Dynamics mode Refer to Separator Calculations for more information. 4. To ignore the vessel operation, select the Ignored check box. Because these vessel operations are so similar, you can quickly change its type without having to delete and define a new operation in your simulation. Refer to the Design tab, Parameters page. Design The Separator, 3-Phase Separator, and Tank Design tab consists of these pages. Connections Use the Connections page to provide names for the outlet/product streams for the vessel. All three vessel operations accept multiple feed streams, as well as an optional energy stream. v 491 Chapter 8: General Unit Operations Separator Property View 3 -Phase Separator Property View 492 v Separator, 3-Phase Separator, and Tank Tank Property View Specify the optional energy input to the vessel by providing the name of the energy stream. The Steady State mode Separator energy balance is defined as: H feed ± Duty = H vapour+H heavy + H light where: H H H H feed = heat flow of the feed stream(s) vapour light = heat flow of the vapour product stream = heat flow of the light liquid product stream heavy = heat flow of the heavy liquid product stream Parameters Use the Parameters page to specify the pressure drop across the vessel. Parameter Description Volume Enter the volume of the vessel. Liquid Volume The Liquid Volume is calculated from the product of the Volume and Liquid Level fraction. Liquid Level Enter a percentage of the Full (Vessel) Volume. v 493 Chapter 8: General Unit Operations Because these vessel operations are so similar, you can quickly change its type without having to delete and define a new operation in your simulation. All original characteristics of the operation (Parameters, Reactions, etc.) are retained with the following exceptions: l l You may only need to identify an additional liquid stream. If you toggle from a Separator operation to a Tank operation, you permanently lose the vapour stream connection. If you change back to the Separator, you have to reconnect the vapour stream. To change the vessel type, select another type from the Type group. Separator Property View 494 v Separator, 3-Phase Separator, and Tank 3 -Phase Separator Property View Tank Property View The physical parameters associated with this operation include: Pressure drop across the vessel (Delta P) The default pressure drop across the vessel is zero. The pressure drop is defined as: P = Pv = Pl = P feed − ∆P v 495 Chapter 8: General Unit Operations where: P = vessel pressure P = pressure of vapour product stream (not applicable for Tank) v P = pressure of liquid product stream(s) l P = pressure of feed stream. P is assumed to be the lowest pressure of all the feed feed feed streams ΔP = pressure drop in vessel (Delta P) Vessel Volume The default vessel volume is 2 m3 . The vessel volume and the set point for liquid level/flow define the amount of holdup in the vessel. The vessel volume is necessary when modelling a Reactor (CSTR), as it determines the residence time. The amount of liquid volume, or holdup, in the vessel at any time is given by the expression Holdup = Vessel Volume * PV (% Full) 100 where: PV(%Full) = liquid level in the vessel at time t You must specify information on the Connections and Parameters pages. You can also add User Variables and Notes. Reactions Use the Separator, 3-Phase Separator, and Tank Reactions tab only if you are setting up the operation as a reactor. In the Reaction Details group, select the Reaction Set from the drop-down list. The grid in the Reaction Results group displays the reaction and component information depending on which option you select. Select... To... Reaction Extents View the Percent Conversion, Base Component, Equilibrium Constant and Reaction Extent. Reaction Balance View the total inflow, total reaction and total outflow for all of the components in the reaction. Optionally, check Ignore reactions when unable to solve. 496 v Separator, 3-Phase Separator, and Tank Reaction Extents Reaction Balance Click View Global Rxn to open the Kinetic Reaction view which allows you to select specific reactions. v 497 Chapter 8: General Unit Operations Rating The Separator, 3-Phase Separator, and Tank Rating tab consists of these pages: Sizing Use the Sizing page to define the vessel's capacity. In the Geometry group, select either Cylinder or Sphere, and then enter the vessel's volume and/or dimensions. Optionally, click Quick Size to have Petro-SIM calculate a size based on a volume. If the vessel has a boot, check This separator has a boot, and then enter the dimensions. If the vessel has a weir, click Weir to define its parameters in the Initial Holdup view. 498 v Separator, 3-Phase Separator, and Tank C(arry) Over Setup This Carry Over Setup page allows you to select how much of each phase is entrained in each product phase stream. Select... To... None Ignore the carry over. Feed Basis Enter the carry over of each phase in the product streams as a fraction of the feed amount of each phase. Entering 0.2 for the Light Liquid in Gas means that 20 mol % of the light liquid phase in the feed will be in the Vapour outlet of the Separator. Product Basis Enter the carry over in each product stream using fractions or flows. From the Basis drop-down list select: Mole, Mass, Liquid Volume, or Actual Volume. Entering 0.2 for the Light Liquid in Gas mole fraction means 20 mol % of the Vapour outlet will be the light liquid phase. If you select the flow option and they enter 20 kgmole/hr Light Liquid in Gas, then if there's enough Light Liquid, there will be 20 kgmole/hr of the Light Liquid phase in the Separator’s Vapour outlet stream. v 499 Chapter 8: General Unit Operations Feed Basis option Product Basis option C(arry) Over Results The Carry Over Results page displays the results of the Carry Over Model in the vessel. From the Basis drop-down list select: Mole, Mass, Liquid Volume, or Actual Volume. Separator Calculations A pressure-enthalpy (P-H) flash is performed to determine the product conditions and phases. The pressure at which the flash is performed is the lowest feed pressure minus the pressure drop across the vessel. The enthalpy is the combined feed enthalpy plus or minus the duty (for heating, the duty is added; for cooling, the duty is subtracted). 500 v Separator, 3-Phase Separator, and Tank As well as standard forward applications, the Separator and 3-Phase Separator can back-calculate results. In addition to the standard application (completely defined feed stream (s) being separated at the vessel pressure and enthalpy); the Separator can also use a known product composition to determine the composition(s) of the other product stream(s) and by a balance the feed composition. In order to back-calculate with the separator, the following information must be specified: l l l One product composition. The temperature or pressure of a product stream. Two (2-phase Separators) or three (3-phase Separators) flows. If you're using multiple feed streams, only one feed stream can have an unknown composition in order for Petro-SIM to back-calculate. v 501 Chapter 8: General Unit Operations Mixer The Mixer operation combines two or more inlet streams to produce a single outlet stream. A complete heat and material balance is performed with the Mixer. The one unknown temperature among the inlet and outlet streams is always calculated rigorously. If the properties of all the Inlet streams to the Mixer are known (temperature, pressure and composition), the properties of the Outlet stream are calculated automatically since the composition, pressure and enthalpy are known for that stream. The mixture pressure and temperature are usually the unknowns to be determined. The Mixer also calculates backwards and determines the missing temperature for one of the inlet streams if the outlet is completely defined. In this latter case, the pressure must be known for all streams. The resultant temperature of the mixed streams may be quite different than those of the feed streams due to mixing effects. The Mixer flashes the outlet stream using the combined enthalpy. Notice when the inlet streams are completely known, no additional information needs to be specified for the outlet stream. The problem is completely defined and no degrees of freedom remain. 1. To add an Mixer to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double click Mixer (or click and drag it to the flowsheet). A Mixer is added to the flowsheet. 502 v Mixer 3. In the Mixer Property view, enter the Mixer properties in these tabs: l Design l Rating l Worksheet l Dynamics - This tab is available only when working in Dynamics mode. 4. To ignore the Mixer during calculations, check Ignored. Design Modify the Mixer Design tab settings on these pages: Connections Use the Connections page to specify the feed and product streams attached to the Mixer. Optionally, change the name of the operation in the Name field. Parameters Use the Parameters page to indicate how pressures should be transferred for the streams attached to the Mixer. v 503 Chapter 8: General Unit Operations In the Automatic Pressure Assignment group, the default option is Set Outlet to Lowest Inlet, in which case all but one attached stream pressure must be known. Petro-SIM assigns the lowest inlet pressure to the outlet stream pressure. Select... Equalize All To... Petro-SIM gives all attached streams the same pressure once one of the attached stream pressures is known. If you select Equalize All and two or more of the attached streams have different pressures, a pressure inconsistency message appears. In this case, you must either remove the pressure specifications for all but one of the attached streams, or select Set Outlet to Lowest Inlet, where you can still set the pressures of all the streams. Set Outlet to Lowest Inlet Specify all of the inlet stream pressures. First ensure that all pressures have been specified before installing the Mixer. In this case, there's no automatic pressure assignment since all the stream pressures are known. If you're uncertain of which pressure assignment to use, choose Set Outlet to Lowest Inlet. Use Equalize All only if you are completely sure all the attached streams should have the same pressure. While the pressure assignment seems extraneous, it is of special importance when the Mixer is being used to simulate the junction of multiple pipe nodes. You can also add User Variables and Notes. 504 v Mixer Rating Use the Mixer Rating tab to define the elevation of the mixer and the nozzle parameters. . v 505 Chapter 8: General Unit Operations Tee The Tee operation splits a feed stream into multiple product streams with the same conditions and composition as the feed stream and is used for simulating pipe tees and manifolds. 1. To add a Tee to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Tee(or click and drag it to the flowsheet). A Tee operation is added to the active flowsheet. 3. In the Tee Property view, enter the Tee properties in these tabs: l Design l Rating l Worksheet l Dynamics - This tab is available only when working in Dynamics mode. 4. To ignore the Tee during calculations, check Ignored. Design Modify the Tee Design tab settings on these pages: Connections Use the Connections page to specify the feed stream as well as any number of product streams, 506 v Tee all of which are assigned the conditions and composition of the feed. The only difference between the products is the flow rates, determined by the flow ratios, which you specify on the Parameters page in Steady State mode. Optionally, you can change the name of the operation in the Name field. Parameters Use the Parameters page to specify the desired flow ratio (the ratio of the outlet stream flow to the total inlet flow). v 507 Chapter 8: General Unit Operations A flow ratio is generally between 0 and 1. A ratio greater than one may be given. In that case, at least one of the outlet streams has a negative flow ratio and a negative flow (backflow). For N outlet streams attached to the Tee, you must specify N-1 flow ratios. Petro-SIM then calculates the unknown stream flow ratio and the outlet flow rates. N ∑ ri = 1.0 i =1 f F ri = i where: r = flow ratio of the ith stream i f = outlet flow of the ith stream i F = feed flow rate N = number of outlet streams For example, if you have 4 outlet streams attached to the Tee, you must give 3 flow ratios, while Petro-SIM calculates the fourth. A ratio is not required. You also have the option of explicitly giving the flows of all but one of the outlet streams. You can do this on the Workbook tab or directly on the stream. You can also add User Variables and Notes. Rating Use theTee Rating tab to define the elevation of the tee and the nozzle parameters. 508 v Tee v 509 Chapter 8: General Unit Operations Cooler/Heater The Cooler and Heater unit operations are one-sided heat exchangers. The difference between the Cooler and Heater is the energy balance sign convention. For more information, refer to Cooler/Heater Theory. 1. To add a Heater or Cooler to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click flowsheet). Cooler or Heater operation icon (or click and drag it to the The Cooler or Heater is added to the active flowsheet. The property views for the Cooler and Heater are identical. 3. In the Cooler or Heater property view, enter the parameters in these tabs: l Design l Worksheet l Performance l Dynamics - This tab is available only when working in Dynamics mode. 4. To ignore the Cooler or Heater during calculations, check Ignored. Design Modify the Cooler/Heater Design tab settings on these pages: 510 v Cooler/Heater Connections The Connections page is used to define all of the connections to the Cooler/Heater. You can specify the inlet, outlet and energy streams attached to the operation on this page. The name of the operation can be changed in the Name field. Parameters The applicable parameters are the pressure drop (Delta P) across the process side and the duty of the energy stream. Both the pressure drop and energy flow can be specified directly or can be determined from the attached streams. Petro-SIM uses the proper sign convention for the unit you have chosen, so you can always enter a positive duty value. v 511 Chapter 8: General Unit Operations You can specify a negative duty value, be aware that: l l For a Cooler, a negative duty means the unit is heating the inlet stream. For a Heater, a negative duty means the unit is cooling the inlet stream. You can also add User Variables and Notes. Performance The Cooler/Heater Performance tab contains the following pages: Tables 512 v Cooler/Heater Plots Cooler/Heater Theory The inlet stream is cooled (or heated) to the required outlet conditions and the energy stream absorbs (or provides) the enthalpy difference between the two streams. These operations are useful when you're interested only in how much energy is required to cool or heat a process stream with a utility, but you're not interested in the conditions of the utility itself.In the general relations, the hot fluid supplies the Heat Exchanger duty to the cold fluid. The Cooler and Heater use the same basic equations. Steady State The primary difference is the sign convention. You specify the absolute energy flow of the utility stream and Petro-SIM then applies that value as follows: l For a Cooler, the enthalpy or heat flow of the energy stream is subtracted from the inlet stream: Heat Flowinlet − Dutycooler = Heat Flowoutlet l For a Heater, the heat flow of the energy stream is added: Heat Flowinlet + Dutycooler = Heat Flowoutlet Pressure Drop The pressure drop of the Cooler/Heater can be determined in one of two ways: v 513 Chapter 8: General Unit Operations l l Specify the pressure drop. Define a pressure flow relation in the Cooler/Heater unit operation by specifying a K value. If the pressure flow option is chosen for pressure drop determination in the Cooler or Heater, a K value is used to relate the frictional pressure loss and flow through the Cooler or Heater . This relation is similar to the general valve equation: flow= density * k P 1 − P 2 This general flow equation uses the pressure drop across the Cooler or Heater without any static head contributions. The quantity, P1 - P2, is defined as the frictional pressure loss that is used to “size” the Cooler or Heater with a K value. 514 v Multistream Exchanger Multistream Exchanger The Multistream Exchanger model solves heat and material balances for Multistream Heat Exchangers such as Liquefied Natural Gas (LNG) Exchangers and heat exchanger networks. The solution method can handle a wide variety of specified and unknown variables. For the overall exchanger, you can specify various parameters, including heat leak/heat loss, UA or temperature approaches. Two solution approaches are employed; in the case of a single unknown, the solution is calculated directly from an energy balance. In the case of multiple unknowns, an iterative approach is used that attempts to determine the solution that satisfies not only the energy balance, but also any constraints, such as temperature approach or UA. When the overall UA is specified and there are multiple hot streams and/or more cold streams, you may need to add other constraints to show how the heat duty or outlet temperature of one cold stream relates to that of other cold streams. Suitable constraints include: l l Temperature difference between one reference hot/cold stream and the other hot/cold streams. Duty ratio between 1 reference hot/cold stream and the other hot/cold streams. The Multistream Exchanger allows for multiple stream connections, while the Heat Exchanger allows only one hot and cold side stream. For more information, refer to Multistream Exchanger Theory. 1. To add an Multistream Exchanger to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Multistream Exchanger (or click and drag it to the flowsheet). A Multistream Exchanger is added to the active flowsheet. v 515 Chapter 8: General Unit Operations 3. In the Multistream Exchanger property view, enter the properties in these tabs: l Design l Worksheet l Performance l Rating - This tab is available only when working in Dynamics mode. 4. To ignore the Multistream Exchanger during calculations, check Ignored. Design Modify the Multistream Exchanger Design tab settings on these pages: Connections Use the Connections page to specify the feed and product streams attached to the Multistream Exchanger. 516 v Multistream Exchanger To add a Side, click Add Side. Any number of Sides can be added. For each exchanger side you add, include the following: l l l l Inlet Stream and Outlet Stream (required) - select from the drop-down lists. Pressure Drop ( required) - enter the value. Hot/Cold - This is used as an estimate for calculations and is also used for drawing the PFD. If a designated hot pass is actually cold (or vice versa), the operation still solves properly. The actual Hot/Cold designation (as determined by the Multistream Exchanger) can be found on the Results page on the Performance tab. Flowsheet - select the flowsheet from the drop-down list. Optionally, change the name of the operation in the Name field. Parameters On the Parameters page, you have access to the exchanger parameters, heat leak/loss options, the exchanger details and the solving behaviour. v 517 Chapter 8: General Unit Operations Exchanger Parameters Rating Method Description Weighted For the Weighted method, the heating curves are broken into intervals, which then exchange energy individually. An LMTD and UA are calculated for each interval in the heat curve and summed to calculate the overall exchanger UA. If there are more than two multistream exchanger sides, then only the Weighted rating method can be used. End Point You have the option of having Petro-SIM perform the calculations for Counter Current (ideal with Ft = 1.0) operation or for a specified number of shell passes. You can specify the number of shell passes to be any integer between 1 and 7. Heat/Leak Loss Heat Leak/Loss group is available only when the Rating Method is Weighted. 518 v Radio Button Description None By default, there is no heat loss or leak when the None radio button is selected. Extremes The heat loss and heat leak are considered to occur only at the end points (inlets and outlets) and are applied to the Hot and Cold Equilibrium streams. Proportional The heat loss and heat leak are applied over each interval. Multistream Exchanger Exchange Details Parameter Description Intervals The number of intervals, applicable only to the Weighted Rating Method, can be specified. For non-linear temperature profiles, more intervals are necessary. Dew/Bubble Point Activate this check box to add a point to the Heat curve for a phase change. Equilibrate All sides that are checked comes to thermal equilibrium before entering into the UA and LMTD calculations. If only one hot stream or cold stream is checked, then that stream is by definition in equilibrium with itself and the results are not affected. If two or more hot or cold streams are checked, then the effective driving force is reduced. All unchecked streams enter the composite curve at their respective temperatures. Step Type Select: l l l Pressure Profile Equal Enthalpy - All intervals have an equal enthalpy change. Equal Temperature - All intervals have an equal temperature change. Auto Interval - Petro-SIM determines where points should be added to the heat curve. The Pressure Profile is updated in the outer iteration loop, using one of the following: l l l l l Constant dPdH - Maintains constant dPdH during update. Constant dPdUA - Maintains constant dPdUA during update. Constant dPdA - Maintains constant dPdA during update. This is not currently applicable to the Multi-stream Exchanger in steady state, as the area is not predicted. Inlet Pressure - The pressure is constant and equal to the inlet pressure. Outlet Pressure - The pressure is constant and equal to the pressure. Specs On the Multistream Exchanger Specs page, the specifications and solver information is organized into three groups. v 519 Chapter 8: General Unit Operations Solver group The Solver group includes the solving parameters used for the exchangers. 520 v Solver Parameter Specification Description Tolerance You can set the calculation error tolerance. Current Error When the current error is less than the calculation tolerance, the solution is considered to have converged. Maximum Iterations You can specify the maximum number of iterations before Petro-SIM stops the calculations. Iteration The current iteration of the outer loop displays. In the outer loop, the heat curve is updated and the property package calculations are performed. Non-rigorous property calculations are performed in the inner loop. Any constraints are also considered in the inner loop. Unknown Variables Displays the number of unknown variables in the multi-stream exchanger. Multistream Exchanger Solver Parameter Specification Description Constraints Displays the number specifications you've placed on the multi-stream exchanger. Degrees of Freedom Displays the number of Degrees of Freedom on the multi-stream exchanger. To help reach the desired solution, unknown parameters (flows, temperatures) can be manipulated in the attached streams. Each parameter specification reduces the Degrees of Freedom by one. The number of Constraints (specs) must equal the number of Unknown Variables. When this is the case, the Degrees of Freedom is equal to zero and a solution is calculated. Unknown Variables group Petro-SIM lists all unknown exchanger variables according to your specifications. Once the unit has solved, the values of these variables will be displayed. Specifications group To add a new specification, click Add button. To view an existing specification, select it and then click View. Use the ExchSpec view to add or view the parameters. The specification list allows you to try different combinations of three specification types. If you have multiple specifications and want to determine which ones should be active, which should be estimates, and which should be ignored, test each combination to see their effect on the results. All specifications are one of three types: Specification Type Description Active An Active specification is one that the convergence algorithm is trying to meet. Notice an active specification always serves as an initial estimate (when the Active check box is activated, Petro-SIM automatically activates the Estimate check box). An active specification exhausts one degree of freedom. Estimate An Estimate is considered an Inactive specification because the convergence algorithm is not trying to satisfy it. To use a specification as an estimate only, deactivate the Active check box. The value then serves only as an initial estimate for the convergence algorithm. An estimate does not use an available degree of freedom. Completely To disregard the value of a specification entirely during convergence, v 521 Chapter 8: General Unit Operations Specification Type Inactive Description deactivate both the Active and Estimate check boxes. By ignoring rather than deleting a specification, it is available if you want to use it later. You can also add User Variables and Notes. Add Exchange Specification You can view or add selected specifications from the Specs page, Design tab on the Multistream Exchanger or Heat Exchanger unit operation. To add a new specification, click Add button. To view an existing specification, select it and then click View. The ExchSpec view contains the following tabs: Parameters The available specification types are listed and described in the table below: 522 v Specification Description Temperature The temperature of any stream attached to the multi-stream exchanger. The hot or cold inlet equilibrium temperature can also be defined. Delta Temp The temperature difference at the inlet or outlet between any two streams attached to the multi-stream exchanger. The hot or cold inlet equilibrium temperatures can also be used. Minimum The minimum temperature difference between the specified pass and the Multistream Exchanger Specification Description Approach opposite composite curve. For example, if you select a cold pass, this is the minimum temperature difference between that cold pass and the hot composite curve. UA The overall UA (product of overall heat transfer coefficient and heat transfer area). LMTD The overall log mean temperature difference. It is calculated in terms of the temperature approaches (terminal temperature differences) in the exchanger. Duty The overall duty, duty error, heat leak or heat loss. The duty error should normally be specified as 0 so that the heat balance is satisfied. The heat leak and heat loss are available as specifications only if Heat Loss/Leak is set to Extremes or Proportional on the Parameters page. Duty Ratio A duty ratio can be specified between any two of the following duties: overall, error, heat loss, heat leak or any pass duty. Flow The flowrate of any attached stream (molar, mass or liquid volume). Flow Ratio The ratio of any two inlet stream flowrates. The Hot Inlet Equilibrium temperature is the temperature of the inlet hot stream minus the heat loss temperature drop. The Cold Inlet Equilibrium temperature is the temperature of the inlet cold stream plus the heat leak temperature rise. The Heat Balance (specified at 0 kJ/h) is considered to be a constraint. This is a Duty Error specification; if you turn it off, the heat equation cannot balance. Without the Heat Balance specification, you can, for example, completely specify all four heat exchanger streams and have Petro-SIM calculate the Heat Balance error, which would be displayed in the Current Value column of the Specifications group. The Heat Balance specification is a default exchanger specification that must be active for the heat equation to balance. v 523 Chapter 8: General Unit Operations Summary The Summary tab is used to define whether the specification is Active or an Estimate. The Spec Value is also shown on this page. Information specified on this tab is also displayed in the Specifications group on the Specs page, Design tab. Performance The Multistream Exchanger Performance tab contains pages that display the results of the Multistream Exchanger calculations. Results The Results page displays the calculated values generated by Petro-SIM. 524 v Multistream Exchanger Overall Performance Parameter Description Duty Combined heat flow from the hot streams to the cold streams minus the heat loss. Conversely, this is the heat flow to the cold streams minus the heat leak. Heat Leak Loss of cold side duty to leakage. Heat Loss Loss of hot side duty to leakage. UA Product of the Overall Heat Transfer Coefficient and the Total Area available for heat transfer. The Multi-stream Exchanger duty is proportional to the overall log mean temperature difference, where UA is the proportionality factor. The UA is equal to the overall duty divided by the LMTD. Minimum Approach The minimum temperature difference between the hot and cold composite curves. LMTD The LMTD is calculated in terms of the temperature approaches (terminal temperature differences) in the exchanger. The equation used to calculate LMTD is: ∆T LM = ∆T1 − ∆T 2 ln(∆T1(∆T 2)) where: ΔT = T 1 ΔT = T 2 hot, out hot, in —T —T cold, in cold, out v 525 Chapter 8: General Unit Operations Detailed Performance Parameter Description Estimated UA Curvature Error The LMTD is ordinarily calculated using constant heat capacity. An LMTD can also be calculated using linear heat capacity. In either case, a different UA is predicted. The UA Curvature Error reflects the difference between these UAs. Hot Pinch Temperature The hot stream temperature at the minimum approach between composite curves. Cold Pinch Temperature The cold stream temperature at the minimum approach between composite curves. Cold Inlet Equilibrium Temperature The Equilibrium Temperature for the cold streams. When streams are not equilibrated (see the Parameters page ), the Equilibrium temperature is the coldest temperature of all cold inlet streams. Hot Inlet Equilibrium Temperature The Equilibrium Temperature for the hot streams. When streams are not equilibrated (see the Parameters page), the Equilibrium temperature is the hottest temperature of all hot inlet streams. Side Results The Side Results group displays information on each Pass. For each side, the inlet and outlet temperatures, molar flow, duty, UA and the hot/cold designation display. Plots You can plot composite curves or individual pass curves. Use the Plot check boxes to specify which curve(s) you want displayed. 526 v Multistream Exchanger You can modify the display of the plot using the Graph Control view. To view the plot area only, click the View Plot button. Variables can be used for either the x or y-axis: l l l l l l Temperature UA Delta T Enthalpy Pressure Heat Flow Select the combination from the Plot Type drop-down list. Tables Use the Tables page to examine the interval Temperature, Pressure, Heat Flow, Enthalpy, UA, Vapour Fraction and Delta T for each side of the Exchanger. From the Side drop-down list, choose either Cold Composite or Hot Composite. Cold Composite v 527 Chapter 8: General Unit Operations Hot Composite Multistream Exchanger Theory Heat Transfer The Multistream Exchanger calculations are based on energy balances for the hot and cold fluids. This general relation applies to any layer in the unit operation. d (VH out) M H in − H out  + Q inte nal + Q exte nal = ρ dt   where: M = fluid flow rate in the layer ρ = density H = enthalpy Q = heat gained from the surrounding layers Q = heat gained from the external surroundings internal external V = volume shell or tube holdup Pressure Drop The pressure drop across any layer in the Multistream Exchanger can be determined in one of two ways: 528 v Multistream Exchanger l l Specify the pressure drop. Define a pressure flow relation for each layer by specifying a K value. If the pressure flow option is chosen for pressure drop determination, a K value is used to relate the frictional pressure loss and flow through the Multistream Exchanger. This relation is similar to the general valve equation: f = density * k P 1 − P 2 This general flow equation uses the pressure drop across the Multistream Exchanger without any static head contributions. P1 - P2, is defined as the frictional pressure loss that is used to “size” the Multistream Exchanger with a K value. v 529 Chapter 8: General Unit Operations Heat Exchanger The Heat Exchanger performs two-sided energy and material balance calculations. The Heat Exchanger is very flexible and can solve for temperatures, pressures, heat flows (including heat loss and heat leak), material stream flows, or UA. Petro-SIM has several model options for solving the exchanger, depending on the level of data available. When the geometry data is not known and you want to perform a heat and material balance on the exchanger, you can choose between these two models: l l End Point Weighted When the geometry is known, you can choose between these two Petro-SIM models: l l Steady State Rating Dynamic Rating Petro-SIM also allows you to link with third party software for geometry-rated calculations. Twoway data transfer is provided between Petro-SIM and these third party programs. l l STX - from Heat Transfer Consultants HTRI - Xist - from Heat Transfer Research Institute For more information, refer also to Heater Exchanger Theory. 1. To add a Heat Exchanger unit operation to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Heat Exchanger(or click and drag it to the flowsheet). A Heat Exchanger unit operation is added to the active flowsheet. 530 v Heat Exchanger 3. In the Heat Exchanger property view, enter the parameters in these tabs: l Design l Rating l Worksheet l Performance l Dynamics - This tab is available only when working in Dynamics mode. 4. To ignore the Heat Exchanger during calculations, check Ignored. Design Modify the Heat Exchanger Design tab settings on these pages: l l l l Connections Parameters Specs Geometry Design You can also add User Variables and Notes. Connections Use the Design tab, Connections page to specify the operation name, as well as the Inlet and Outlet streams for the Shell and Tube Sides. Optionally, change the name of the operation in the Name field. v 531 Chapter 8: General Unit Operations The main flowsheet is the default flowsheet for the Shell and Tube Sides. You can select a subflowsheet on the Tube and/or Shell Sides that allows you to choose Inlet and Outlet streams from that flowsheet. This is useful for processes such as a Refrigeration cycle, which requires separate fluid packages for each side. You can define a sub-flowsheet with a different fluid package and then connect to the main flowsheet Heat Exchanger. Parameters Use the Design tab, Parameters page to select the Heat Exchanger Model. When a heat exchanger is installed as part of a column sub-flowsheet (available when using the Modified Inside-Out solving method), these Heat Exchanger Models are not available. Instead, in the column sub-flowsheet, the heat exchanger is Calculated from Column as a simple heat and mass balance. 532 v Heat Exchanger 1. From the Heat Exchanger Model drop-down list, choose one of these models: Exchanger Design (Weighted) The Weighted model is an excellent model to deal with non-linear heat curve problems such as the phase change of pure components in one or both Heat Exchanger sides. With the Weighted model, the heating curves are broken into intervals and an energy balance is performed along each interval. Individual LMTD and UA values are calculated for each interval in the heat curve and summed to calculate the overall exchanger UA. The Weighted model is available only for counter-current exchangers and is essentially an energy and material balance model. Petro-SIM makes use of the number of shells and tube/shell passes to determine the Ft correction factor. This can be used to determine the effect of the number of shells on exchanger effectiveness. The parameters available on the Parameters page when the Weighted model is selected are: Parameter Description Pass Name For each side of the Heat Exchanger, Pass Name identifies the shell and tube side according to the names you provided on the Connections page. Intervals The number of intervals can be specified. For non-linear temperature profiles, more intervals are necessary. Dew/Bubble Point Check to add a point to the heat curve for the dew and/or bubble point. If there is a phase change occurring in either pass, the appropriate check v 533 Chapter 8: General Unit Operations Parameter Description box should be activated. Step Type Select: l l l Equal Enthalpy - All intervals have an equal enthalpy change. Equal Temperature - All intervals have an equal temperature change. Auto Interval - Petro-SIM determines where points are added to the heat curve. Pressure Profile Select one of these methods to update the Pressure Profile in the outer iteration loop: l l l l l Constant dPdH - Maintains constant dPdH during update. Constant dPdUA - Maintains constant dPdUA during update. Constant dPdA - Maintains constant dPdA during update. This is not currently applicable to the Heat Exchanger, as the area is not predicted. Inlet Pressure - Pressure is constant and equal to the inlet pressure. Outlet Pressure - Pressure is constant and equal to the outlet pressure. Exchanger Design (End Point) The End Point model is based on the standard Heat Exchanger duty equation defined in terms of overall heat transfer coefficient area available for heat exchange and the log mean temperature difference. 534 v Heat Exchanger The main assumptions of the model are: l l Overall heat transfer coefficient, U is constant. Specific heats of both shell and tube side streams are constant. The End Point model treats the heat curves for both Heat Exchanger sides as linear. For simple problems where there is no phase change and C is relatively constant, this option P may be sufficient to model your Heat Exchanger. For non-linear heat flow problems, the Weighted model should be used instead. Steady State Rating The Steady State Rating model for the Heat Exchanger is an extension of the End Point model and uses the same assumptions to incorporate a rating calculation. Detailed geometry must be entered on the Rating tab to allow the exchanger performance to be determined by its geometry. For single phase heat transfer, the Steady State Rating model calculates the heat transfer coefficients and pressure drop values from the Bell Delaware1 method. Dynamic Rating The Heat Exchanger Dynamic Rating model uses the Petro-SIM dynamic solver to calculate the exchanger performance from the detailed geometry entered on the Rating tab. 1Refer to Chapter 3, Wolverine Tube Inc., Engineering Databook III, Single Phase Shell Side Flows and Heat Transfer. v 535 Chapter 8: General Unit Operations STX Selecting STX as the solution model provides a link to the STX shell-and-tube exchanger program from Heat Transfer Consultants. The Rating tab and Specs page views change when STX mode is chosen. These views show the STX data input forms required to run STX. There are two modes of operation when the STX option is selected. STX Solve Mode When STX mode is set to Solve, then STX is used to solve the exchanger given the geometry entered on the Rating tab. This mode can be used to solve for unknown 536 v Heat Exchanger temperatures, pressure drops, or flows. You can also override the pressure drop calculations by entering the pressure drop on the Rating tab, Parameters page or by entering the inlet and outlet pressures on the streams attached to the exchanger. When using Solve mode, the Heat Exchanger iterates on the STX results until the service heat duty and pressure drop values are converged. The convergence criteria are set by the convergence parameters on the Exchanger page of the Rating tab. In this mode, STX cannot be run in Design mode and there is no functional difference between STX rating and evaluation modes. STX Report Mode When STX mode is set to Report, STX is used to generate reports on the exchanger configuration. The heat exchanger must be specified with enough information to solve using the Weighted method (pressure drops, inlet streams and duty). STX then runs given those inlet and outlet conditions and generates the output reports on the Performance tab. This method can be used to determine if an existing exchanger is suitably surfaced for the given process conditions. In either STX mode, all of the input parameters for STX can be entered on the Heat Exchanger views in Petro-SIM. The reports generated by STX are also imported automatically into Petro-SIM and displayed on the Performance tab, from which, you can also export STX standalone files using the STX Files page. Any error messages generated by STX during runs can be found on the Error Msg page. HTRI Xist Heat Exchanger The HTRI Xist Heat Exchanger model is only available if you have HTRI Xchanger Suiteinstalled on your computer. HTRI includes components for heat transfer and associated calculations of heat exchangers and fired heaters. For information about installing HTRI, refer to the HTRI Installation and License Update Guide. The HTRI Xist module only works with shell and tube heat exchangers that use the Xist model in HTRI. It does not work with other styles of heat exchangers or with other forms of heat transfer equipment such as heaters or coolers. 1. To enable Petro-SIM to work with the HTRI Xist Heat Exchanger model, you must first register the HTRI DLL extension using the SIM Suite Registration Tool. v 537 Chapter 8: General Unit Operations The PetroSIMExtn.dll can be found in c:\HTRI\Shared\. 2. From the Heat Exchanger unit operation, Design tab, Parameters page, select HTRI Xist Heat Exchanger. 3. Click Launch HTRI to open HTRI where you can view/edit the data that is shared with Petro-SIM. The HTRI Xchanger Suite application displays the heat exchanger details. 4. Petro-SIM transfers the process data and any known geometry data to HTRI. PetroSIM sets the Case mode in HTRI to be Rating if three temperatures have been specified for the exchanger. Otherwise, it is set to Simulation. In HTRI, you can select one of the following Case modes: l Rating mode is used when the exchanger duty is known and specified. Generally this information is made up of the inlet fluid properties and three stream temperatures. When the detailed exchanger geometry is supplied, HTRI is then able to calculate the percentage over-design or under-design of the exchanger. l Simulation mode requires less process information, which results in the exchanger initially having an unknown duty. Generally only the inlet fluid properties and inlet stream temperatures are entered. Once the detailed exchanger geometry is supplied, HTRI is able to calculate the expected performance of the exchanger. l Design mode is used to vary the exchanger geometry to achieve a given heat duty and pressure drop. HTRI designs the smallest exchanger that is able to satisfy the entered geometrical, process, and physical property requirements. Heat duty must be entered, along with a number of exchanger geometries. 538 v Heat Exchanger For more information about using the HTRI Xchanger Suite, refer to the application's user documentation. 5. When you are done defining all parameters in HTRI for the Heat Exchanger, in Petro-SIM, click Update to run the case. Results are carried over to Petro-SIM when the exchanger has converged and can be viewed on the Heat Exchanger Rating and Performance tabs or in the HTRI on its Results tab . 2. For both Endpoint and Weighted models, specify whether your Heat Exchanger experiences Heat Leak1 or Heat Loss2. From the Heat Leak/Loss group, select: Select... Description None None is the default. No heat/loss is selected. Extremes On the hot side, the heat is considered to be “lost” where the temperature is highest. Essentially, the top of the heat curve is being removed to allow for the heat loss/leak. This is the worst possible scenario. On the cold side, the heat is gained where the temperature is lowest. Proportional The heat loss is distributed over all of the intervals. 3. In the Tube Side/Shell Side model, enter the parameters in the Delta P and UA fields: All Heat Exchanger models allow for the specification of either Counter or Co-Current tube flow. The parameters listed in the table below are available when either the End Point, Weighted, or Steady State Rating model is selected. Parameters Description Delta P On both Tube Side and Shell Side, specify the pressure drops (DP) for the tube and shell sides for the exchanger. If you do not specify the Delta P (pressure drop) values, Petro-SIM calculates them from the attached stream pressures. UA The product of the Overall Heat Transfer Coefficient and the Total Area available for heat transfer. The Heat Exchanger duty is proportional to the log mean temperature difference, where UA is the proportionality factor. The UA can either be specified, or calculated by Petro-SIM. 1Loss of cold side duty due to leakage. Duty gained to reflect the increase in temperature. 2Loss of hot side duty due to leakage. Duty lost to reflect the decrease in temperature. v 539 Chapter 8: General Unit Operations Specs The Design tab, Specs page is organized in three groups that show the various specification and solver information. The information provided on the Specs page is only valid for the Weighted, End Point, and Steady State Rating models. Solver group Parameters Details Tolerance Set the calculation error tolerance. Current Error When the current error is less than the calculation tolerance, the solution is considered to have converged. Iterations The current iteration of the outer loop displays. In the outer loop, the heat curve is updated and the property package calculations are performed. Non-rigorous property calculations are performed in the inner loop. Any constraints are also considered in the inner loop. Unknown Variables Petro-SIM lists all unknown Heat Exchanger variables according to your specifications. Once the unit has solved, the values of these variables are displayed. Specifications group To add a new specification, click Add. To view an existing specification, select it and then click View. Use the ExchSpec view to add or view the parameters. The specification list allows you to try different combinations of three specification types. If you have multiple specifications and want to determine which ones should be active, which should be estimates, and which should be ignored, test each combination to see their effect on the results. 540 v Heat Exchanger All specifications are one of three types: Specification Type Description Active An Active specification is one that the convergence algorithm is trying to meet. Notice an active specification always serves as an initial estimate (when the Active check box is activated, Petro-SIM automatically activates the Estimate check box). An active specification exhausts one degree of freedom. Estimate An Estimate is considered an Inactive specification because the convergence algorithm is not trying to satisfy it. To use a specification as an estimate only, deactivate the Active check box. The value then serves only as an initial estimate for the convergence algorithm. An estimate does not use an available degree of freedom. Completely Inactive To disregard the value of a specification entirely during convergence, deselect both the Active and Estimate check boxes. By ignoring rather than deleting a specification, it is available if you want to use it later. Geometry Design The Design tab, Geometry Design page displays parameters relating to the design of the exchanger geometry. It is used to set the design values for the Shell Side and Tube Side parameters. You can specify the following data for an existing design. v 541 Chapter 8: General Unit Operations Parameters Description Pressure Enter the design pressure for each side. If not specified, a default value is set based on the inlet stream pressure plus 10%. Temperature Enter the design temperature for each side. Corrosion Allowance Enter the corrosion allowance that appears on the TEMA Spec report. Fouling The design fouling values are useful for comparing how the fouled state of the exchanger compares with design. They are used by the Heat Exchanger-Monitor utility. Allowable Pressure Drop Set the allowable pressure drop that can be used for manual comparison with the achieved pressure drop. Petro-SIM can also be used to search for a preliminary design. Click Add or Show Geometry Design to open the Geometry Design view where you can find new geometries that satisfy a given duty or the current duty achieved in the exchanger. Rating The Heat Exchanger Rating tab contains the following pages: Sizing The Sizing page provides Heat Exchanger sizing related information. Based on the geometry information, Petro-SIM can calculate the pressure drop and the convective heat transfer coefficients for both Heat Exchanger sides and rate the exchanger. 1. From the Sizing Data group, select one of these options: l Overall l Tube l Shell 2. De-select Accept any input data to validate that the input data is consistent and realistic with the TEMA type selected. 3. Optionally, select the Heat Exchanger Model. Refer to the Parameters page for details about the models. Parameters If the Heat Exchanger is using the Dynamic Rating Model, select the Model type and enter the applicable data. 542 v Heat Exchanger Nozzles Define the elevation of the Heat Exchanger and the nozzle parameters. Heat Loss Select the Heat Loss Model and enter the corresponding parameters. v 543 Chapter 8: General Unit Operations Simple Detailed Overall Select Overall on the Rating tab, Sizing page, to modify the overall Heat Exchanger geometry. 544 v Heat Exchanger 1. In the Configuration group, specify whether multiple shells are used in the Heat Exchanger design: Field Description Number of Shell Passes You have the option of Petro-SIM performing the calculations for Counter Current (ideal with Ft = 1.0) operation or for a specified number of shell passes. Specify the number of shell passes to be any integer between 1 and 7. When the shell pass number is specified, Petro-SIM calculates the LMTD correction factor (Ft) for the current exchanger design. A value lower than 0.8 generally corresponds to inefficient design in terms of the use of heat transfer surface. More passes or larger temperature differences should be used in this case. For n shell passes, Petro-SIM solves the heat exchanger on the basis that at least 2n tube passes exist. Charts for Shell and Tube Exchanger LMTD Correction Factors, as found in the GPSA Engineering Data Book, are normally in terms of n shell passes and 2n or more tube passes. In general, at least 2n tube passes must be specified for every n shell pass. The exception is a Counter current flow Heat Exchanger that has one shell pass and one tube pass. Number of If a multiple number of shells are specified in series, the configuration is v 545 Chapter 8: General Unit Operations Field Description Shells in Series shown as follows: Number of Shells in Parallel If a multiple number of shells are specified in parallel, the configuration is shown as follows: Tube Passes per Shell The number of tube passes per shell. The default setting is 2 (i.e., the number of tubes equal to 2n, where n is the number of shells.) Exchanger Orientation Select Horizontal or Vertical. This is important for condensing exchangers. First Tube Pass Select whether the tube feed is Co-current or Counter-current for all heat Flow Direction exchanger calculation models. Elevation (base) Enter the elevation and select the units from the drop-down list. 2. From the TEMA Type drop-down lists, select the shape of Heat Exchanger: l From the first drop-down, select the front end stationary head types. l From the second list, select the shell types. l From the third list, select a list of rear end head types. 546 v Heat Exchanger For a more information about TEMA-style shell-and-tube heat exchangers, refer to Perry’s Chemical Engineers’ Handbook1 . 3. In the Calculated Information group, view or modify the following Heat Exchanger parameters: l Heat Exchanger Duty l Shell HT Coeff l Tube HT Coeff l Overall U l Overall UA l Exchanger Ft Factor l Shell DP l Tube DP l Shell Side Velocity l Tube Side Velocity l HT Area for single shell l Over design - When the exchanger duty is specified directly on the Specs page or determined through three specified temperatures, this parameter indicates whether the exchanger is oversized (over design is greater than zero) or undersized (over design is less than 0) for the required duty. Fouling in an exchanger would cause it to achieve a duty that is lower than what the exchanger is capable of, given its size and geometry. A fouled exchanger would appear to be oversized when the full fouling value has not been specified. If you set the Over design to 0, Petro-SIM calculates the fouling factors for the exchanger. l Tube Volume per Shell l Shell Volume per Shell 1Perry, R.H. and D.W. Green. Perry’s Chemical Engineers’ Handbook (Seventh Edition) McGraw-Hill (1997) p. 11-33 (1997 edition). v 547 Chapter 8: General Unit Operations Tube Select Tube on the Rating tab, Sizing page, to modify the tube geometry information in each shell. 548 v Heat Exchanger 1. Specify the tube geometric parameters in the Dimensions group: Field Description Tube Inlet Stream This is a display of the tube inlet stream specified on the connections page. Outer Tube Diameter (OD) Inner Tube Diameter (ID) Tube Thickness Two of the three listed parameters must be specified to characterize the tube width dimensions. Tube Length Heat transfer length of one tube in a single Heat Exchanger shell. This value is not the actual tube length. Tube Inlet Nozzle Diameter The nozzle diameter at tube inlet. If not specified, this will be set to a value that keeps nozzle pressure drop within 25% of the total tube side pressure drop. Tube Outlet Nozzle Diameter The nozzle diameter at tube outlet. Default values will be evaluated by Petro-SIM but can be over-written. Tube Fouling The tube fouling factor is taken into account in the calculation of the overall heat transfer coefficient, UA. 2. In the Tube Properties group, select the Tube Material type from the drop-down list and Petro-SIM automatically displays the corresponding Thermal Conductivity. You can, optionally, modify the value. 3. If Dynamic Rating Model is selected in the Parameters page, specify the following additional properties in the Dynamic Tube Properties group: l Wall Cp - specific heat capacity l Wall Density 4. In the Tube Side Enhancement group, enter a percentage in the Enhancement field to evaluate how the exchanger performs causing the Raw Value properties to change: l Tube Side Heat Transfer Coefficient l Tube Side Pressure Drop Shell Select Shell on the Rating tab, Sizing page, to modify the shell configuration and baffle arrangement in each shell. v 549 Chapter 8: General Unit Operations 1. In the Shell and Tube Bundle Data group, specify how the tube bundle is arranged within the shell: In this field Do this... Shell Inlet Stream Modify the shell inlet stream. This is typically selected on the Connections page. Central Baffle Spacing Enter the space between each baffle and select the units from the dropdown list. Number of Specify the number of tubes in the shell Tubes per Shell Tube Pitch Enter the shortest distance between the centres of two adjacent tubes. This must be greater than the tube outlet diameter. Tube Layout Angle Select how the tubes in a single shell are arranged: l l l l Triangular (30 degrees) Triangular Rotated (60 degrees) Square (90 degrees) Square Rotated (45 degrees) For more information about the benefits of different tube layout angles, refer to Process Heat Transfer1. Baffle cut Enter the baffle cut as a percentage of the shell diameter. This option is 1Kern, Donald Q. Process Heat Transfer Tata Mcgraw Hill Education Private Limited p.139 (1965). 550 v Heat Exchanger In this field Do this... only relevant for segmented baffle types. It is not shown when the baffle type is Single Helix or Double Helix. Helix angle Enter the angle between the baffle quadrant and the plane perpendicular to the tube axis. The helix angle is between 6° and 40°, in 1° increments. Shell Inside Diameter Enter the shell diameter. If not specified, Petro-SIM determines the minimum shell diameter if all other tube and shell data are provided. Shell Inlet Enter the nozzle diameter at shell inlet. Petro-SIM determines the diameter Nozzle Diameter if all other tube and shell data are provided. Shell Outlet Enter the nozzle diameter at shell outlet. Petro-SIM determines the Nozzle Diameter diameter if all other tube and shell data are provided. Shell Fouling Enter the shell fouling factor that is taken into account in the calculation of the overall heat transfer coefficient, UA. 2. Under the Shell and Baffle Clearances group, specify the shell clearances and indicate if the baffle type refers to: Shell and Tube Exchanger with Segmented Baffles HELIXCHANGER with Helical Baffles The HELIXCHANGER® Heat Exchanger is a proprietary technology licensed by Lummus Heat Transfer (LHT) and fabricated under license from LHT. v 551 Chapter 8: General Unit Operations Helical Baffles are quadrants which are cut from elliptical-shaped plates. The quadrants are angled with respect to the plane normal to the tube axis. The function of these baffles is to create a swirling or pseudo-helical flow pattern. Baffles can be placed as single or double helix. A double helix is simply two inter-winding helix arrangements, one placed exactly opposite to the other. The Double Helix arrangement provides extra tube support with similar shell side thermal performance. In the following images, the CFD flow model of the HELIXCHANGER is compared with that of the segmentally baffled exchanger. Petro-SIM evaluates the properties entered to calculate several of the parameters, but you can modify them as required. In this field... Do this... Shell Baffle Type Select the baffle type from the drop-down list. 552 v Shell Baffle Orientation Select Vertical or Horizontal baffles. Inlet Baffle Spacing Enter the spacing between the first baffle and the shell inlet nozzles. Outlet Baffle Spacing Enter the spacing between the last baffle and the shell outlet nozzles. Heat Exchanger In this field... Do this... Bundle to Shell Clearance Enter the separation between the tube bundle and the shell ID. Baffle to Shell Clearance Enter the diametric difference between the nominal shell ID and the nominal OD of the baffle plate. Tube to Baffle Clearance Enter the diametric difference between the nominal tube OD and the nominal tube hole diameter in the baffle plate. Number of Sealing Strip Pairs Enter the number of sealing strip pairs used to prevent excessive bypassing of shell side fluid around or through the tube bundle. Has Impingement Plate Select Yes if a plate is used to protect the tube bungle against impingement from excessive shell side fluid flow. Performance The Performance tab has pages that display the results of the Heat Exchanger overall performance including plots and tables. Details Overall Performances Group The Overall Performance group contains the following parameters that are calculated by PetroSIM: v 553 Chapter 8: General Unit Operations Parameter Description Duty Heat flow from the hot stream to the cold stream. Heat Loss Loss of the hot side duty to leakage. The overall duty plus the heat loss is equal to the individual hot stream duty defined on the Tables page. UA Product of the Overall Heat Transfer Coefficient and the Total Area available for heat transfer. The UA is equal to the overall duty divided by the LMTD. Minimum Approach The minimum temperature difference between the hot and cold stream. LMTD The uncorrected LMTD multiplied by the Ft factor. For the Weighted Rating Method, the uncorrected LMTD equals the effective LMTD. Detailed Performance Group The Detailed Performance group contains the following parameters that are calculated by Petro-SIM: 554 v Parameter Description UA Curvature Error UA Curvature error. Hot Pinch Temperature The hot stream temperature at the minimum approach. Cold Pinch Temperature The cold stream temperature at the minimum approach. Ft Factor The LMTD (log mean temperature difference) correction factor, Ft, is calculated as a function of the Number of Shell Passes and the temperature approaches. For a counter-current Heat Exchanger, Ft is 1.0. For the Weighted rating method, Ft = 1. Uncorrected LMTD (Applicable only for the End Point method) - The LMTD is calculated in terms of the temperature approaches (terminal temperature differences) in the exchanger Inlet Wall Temperature Temperature of the wall at tube side inlet Outlet Wall Temperature Temperature of the wall at tube side outlet Heat Exchanger Parameter Description Shell Reynold's No. Reynold’s number for the shell side Tube Reynold's No. Reynold’s number for the tube side Uncorrected LMTD equation: ∆T LM = ∆T1 − ∆T 2 ln(∆T1 / (∆T 2)) where: ∆T1 = T hot, out − T cold, in ∆T 2 = T hot, in − T cold, out Model Summary The Heat Exchanger operation in Petro-SIM is very flexible because the performance of the exchanger can be specified by a number of different properties that are shown on different pages. The model summary highlights the properties that the exchanger is defined by. Plots You can plot curves for the hot and/or cold fluid. Use the Plot check boxes to specify which side (s) of the exchanger should be plotted. Check the Plot options you want to view. Select the combination of parameters you want to view from the Plot Type drop-down list. v 555 Chapter 8: General Unit Operations For more information about modifying the plot, refer to Graph Control. Tables On the Tables page, you can view the interval temperature, pressure, heat flow, enthalpy, UA and vapour fraction for each side of the Exchanger in a tabular format. Select either the Shell Side or Tube Side to view each set of parameters. Error Msg The Error Msg page contains a list of the warning messages on the Heat Exchanger. You cannot add comments to the page, but you can check if there are any warnings in modelling the Heat Exchanger. Use the editing tools to modify the error messages. To print the messages, right-click the background and choose Print. TEMA Spec. The TEMA Spec(ification) page reports the exchanger configuration as well as the physical properties and exchanger performance details in the Heat Exchanger Specification Sheet, a format similar to that recommended by TEMA. 556 v Heat Exchanger Use the editing tools to modify the report if necessary. To print the report, right-click the background and choose Print. Click Copy and Past to Excel to copy the report and open it in an Excel spreadsheet. Heater Exchanger Theory The Heat Exchanger calculations are based on energy balances for the hot and cold fluids. (M cold(H out − H in)cold − Q leak) − (M hot(H in − H out)hot − Q loss) = Balance Error where: M = fluid mass flow rate H = enthalpy Q = heat leak Q = heat loss leak loss The Balance Error is a Heat Exchanger Specification that equals zero for most applications. The subscripts hot and cold designate the hot and cold fluids, while in and out refer to the inlet and outlet. The total heat transferred between the tube and shell sides (Heat Exchanger duty) can be defined in terms of the overall heat transfer coefficient, the area available for heat exchange and the log mean temperature difference: Q = UA ∆TTM Ft where: v 557 Chapter 8: General Unit Operations U = overall heat transfer coefficient A = surface area available for heat transfer ΔT TM = log mean temperature difference (LMTD) F = LMTD correction factor t The Heat Exchanger operation allows the heat curve for either side of the exchanger to be broken into intervals. Rather than calculating the energy transfer based on the terminal conditions of the exchanger, it is calculated for each of the intervals, then summed to determine the overall transfer. The heat transfer coefficient and the surface area are often combined for convenience into a single variable referred to as UA. The LMTD and its correction factor are defined in the Performance section. Pressure Drop The pressure drop of the Heat Exchanger can be determined in one of three ways: l l l Specify the pressure drop. Calculate the pressure drop according to the Heat Exchanger geometry and configuration. Define a pressure flow relation in the Heat Exchanger by specifying a K value If the pressure flow option is chosen for pressure drop determination in the Heat Exchanger, a K value is used to relate the frictional pressure loss and flow through the exchanger. This relation is similar to the general valve equation: f = density * k p 1p 2 This general flow equation uses the pressure drop across the Heat Exchanger without any static head contributions. The quantity, P1 - P2, is defined as the frictional pressure loss that is used to size the Heat Exchanger with a K value. Thermal Sizing of a Shell and Tube Heat Exchanger The Heat Exchanger Models in Petro-SIM (for example, Steady State Rating model, HTRI model) expect the heat exchanger configuration to be specified by the user, which makes it suitable for modelling an existing exchanger in a retrofit situation. When the simulation is a proposed new exchanger, these parameters, (that is, number of tubes, baffle spacing, etc.) are unknown. Design engineers would benefit from a tool that assists in choosing the optimal values for these parameters in a front end engineering and design (FEED) exercise. Geometry design of a heat exchanger comes after the following thermal specifications of the heat exchanger have been defined: 558 v Heat Exchanger l l l l Exchanger Heat Duty Stream Temperatures Allowable Pressure Drop for the shell side and the tube side Minimum and maximum velocity limits for the shell side and the tube side Once these have been defined along with the tube material and shell baffle type, Petro-SIM’s geometry design tool can be used to search for the best combination of the other parameters to ensure the constraints are satisfied and the capital cost is minimized. The other parameters include: 1. Tube/Shell side allocation 2. Selection of exchanger TEMA type l TEMA 1: Front Type l TEMA 2: Shell Type l TEMA 3: End Type 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. Tube Length Tube OD Tube Thickness Tube Layout Tube Pitch Number of Tubes Number of Tube Passes Baffle Cut Baffle Spacing Shell ID Number of Shells in Series Number of Shells in Parallel Shell Inlet and Outlet Nozzle Diameters Tube Inlet and Outlet Nozzle Diameters Petro-SIM's geometry design tool is not a replament for a detailed design tool but is for preliminary screening and optimisation of single phase shell and tube designs. The designs are presented without warranties of any kind either express or implied. Geometry Design View To open the Geometry Design view, from the Design tab, Geometry Design page, click Add or Show Geometry Design. v 559 Chapter 8: General Unit Operations The Geometry Design view is made up of the following tabs that display the data, options, and results for new geometries for a given duty or the current duty achieved in the exchanger. l l l l l Initialize Basis Geometry Options Calculate Designs Initialize The Geometry Design, Initialize tab provides the options for initializing the design basis. Many of these options can be changed on the other tabs but the start-up values are determined by the options that you specify on this page. 560 v Heat Exchanger 1. From the Initialization Basis drop-down select one of these options: Select... Description Thorough design choices Considers typical dimensions of 20-feet tubes with 0.75inch and 1-inch outside diameters (ODs) but adds 1.25 inch to the list to maximize the chances of finding a suitable design. It also considers shorter tubes for small exchanger duties and longer tubes for larger duties. Petro-SIM uses this as the default initialization basis. 20 ft length and ¾ inch OD tubes Many industrial sites prefer to use a standard tube length (typically 20-feet) for their shell and tube exchangers. Also, tubes with a 0.75-inch OD are typical because this is smallest tube size that can be cleaned with mechanical tools. The tube pitch ratio of 1.333 is used as this is the industrial standard for 0.75-inch tubes. 20 ft length and 1 inch OD tubes Although narrower tubes are more efficient for heat recovery, wider tubes may sometimes be required to ease cleaning when the tube side fluid has a high fouling tendency. The 1-inch OD option is recommended when a high fouling stream is involved. The tube pitch ratio of 1.25 is used as this is the industrial standard for 1-inch tubes. 20 ft length and 1 inch or ¾ inch OD tubes Combines the second and third options above. Retrofit: Replace Tube Bundle This option is suitable when retrofitting an existing exchanger to re-arrange the tube bundle. Petro-SIM fixes the TEMA type, nozzle diameters, tube length, and the shell diameter. The total number of shells is taken as maximum, but Petro-SIM varies the arrangement as parallel/serial shells. Also, only multiples of the current number of tube passes are considered during the design. The default sort criteria will be over-designs, rather than relative cost. All possible design choices Considers all tube lengths that are practical for the rear head type of choice. For fixed tubesheet and U tube exchangers, all tube lengths from 8 to 40 feet are considered, but for floating tubesheet exchangers 8 to 30 feet tube lengths are considered. Also considers all practical tube ODs. v 561 Chapter 8: General Unit Operations 2. In the Source of Design Constraints group, select the initial values for the shell and tube sides for each of these design constraints (Allowable Pressure Drops, Minimum Velocities, and Design Fouling Factors). Select: l Set by User - user defined. l Program Suggests - allow Petro-SIM to suggest values. l From Current Hx Solution - allow the Heat Exchanger solution determine the values. 3. From the Cleaning Impact group, inidcate if you wish to enable U tube exchangers to be considered. Care must be taken to ensure that cleaning around the U bend can be carried out effectively bif these exchangers are to be used. 4. From the Baffle Type drop-down, select one of these baffle types. l Single (segmented) l Double (segmented) l Triple (segmented) l Single Helix l Double Helix 5. Click Initialize to set the initialization basis and sources options on the Basis tab. 6. Click Initialize and Calculate to initialize the design basis and automatically start searching for designs. Refer also to Calculate. 7. Optionally, click Delete All Designs to remove any unnecessary designs after you have analyzed and saved any selected designs for future consideration. Basis Use the Geometry Design, Basis tab to define the shell and tube exchanger. 562 v Heat Exchanger 1. In the Stream Data group, define the process data in these fields. Data Description Heat Duty This is the duty achieved by the exchanger as shown on the rating tab. Temperature Cross This is calculated as TCout – THout. When this value is greater than zero, the effectiveness of the E shell exchanger reduces and multiple shells or multiple shell passes (F shell) becomes necessary to improve the effectiveness. Values lower than zero are not reported as they have no significance on design. Temperature Difference This is calculated as THin – TCin. When this value is greater than 60°C, fixed tubesheet exchangers are not suitable and you are not allowed to select these for consideration. Target Overdesign The Heat Duty specified is fixed when searching for designs. With 0% overdesign, the exchanger is designed with sufficient surface area to ensure that the heat duty is achieved, but you can build some contingency into the design by setting the overdesign to be greater than 0%. Overdesign Tolerance The calculated overdesign is allowed to exceed the target overdesign by this tolerance. Phase Change Tolerance Petro-SIM cannot accurately determine the pressure enthalpy profile for design calculations when phase change is involved. You can change the tolerance value for indicating when the pressure effects on phase change enthalpy becomes so significant as to make the design results unreliable. Inlet Pressure Same as that on the streams Worksheet tab for the inlet stream on the hot and cold sides. The stream pressures are considered in the recommendation for tube side allocation, the choice of rear head type, and in the range of tube thickness. Inlet Temperature Same as that on the streams Worksheet tab for the inlet stream on the hot and cold sides. Temperature Cross Although narrower tubes are more efficient for heat recovery, wider tubes may sometimes be required to ease cleaning when the tube side fluid has a high fouling tendency. The 1-inch OD option is recommended when a high fouling stream is involved. The tube pitch ratio of 1.25 is used as this is the industrial standard for 1-inch tubes. v 563 Chapter 8: General Unit Operations Data Description Fouling Factor Enter the design fouling factors. The minimum acceptable value is 0.0005 F.h.ft2/BTU. These values are independent from the rating data even though they may have been determined from shell and tube data on the Rating tab. The factors relating to design are displayed on this page. The values obtained during exchanger operation are required on the Rating tab. Allowable Strm DeltaP The designs presented by Petro-SIM will have pressure drop values that are less than or equal to this value. Maximum Velocity Petro-SIM calculates the maximum velocity from stream specific gravity. Maximum Stream Flow Enter the percentage of the stream flow to accommodate the nozzle diameters. Construction Material The material of construction is used to guide the preference for tube side allocation. It is also used in determining the relative cost for the designs generated. 2. In the Design Constraints group, enter these constraints: Data Description Minimum Velocity Using high values for the minimum velocities speeds up the search for designs and leads to fewer designs as those designs with lower velocities are stripped out. 3. When the fouling factors are as yet unknown, click Estimate Fouling Factors to derive the stream fouling factor from the specific gravity. 4. When the allowable pressure drop values are as yet unknown, click Estimate Allowable DPs to derive them from the exchanger UA. When the UA is large, either because of a large duty or because of small driving forces, the allowable pressure drop is expected to be higher. Petro-SIM determines the allowable pressure drop as a function of exchanger UA. 5. In the Size Validity Limits group, enter the minimum and maximum values that should be considered for an acceptable design. The limits may have been defined by plot limitations on site or by standardization rules for exchangers on a given processing site. You should specify the values, but Petro-SIM can start with initial values that can be overwritten with better site-specific data. 564 v Heat Exchanger Parameter Description E shells in Series The minimum number of shells in series is initially determined by PetroSIM as the number required to achieve an effectiveness (Ft) factor of 0.8 or above. Sometimes more shells than the minimum number are required to achieve the heat duty without the need for excessively long tubes. Petro-SIM initializes the maximum value such that to add seven extra shells to meet the duty (i.e. Max = Min+7). Shells in Parallel Petro-SIM considers several shells in parallel as a means of reducing the pressure drop on the shell and tube sides to meet the allowable pressure drop values. You can restrict the number of shells in parallel by changing the values. Tube Passes One way to increase the velocity on the tube side is to increase the number of tube passes, but this also increases the pressure drop on the tube side. You can limit the values considered. Tube Thickness For every tube outer diameter (Tube OD), there is a specific set of tube by OD (%) thicknesses that are used in industrial exchangers. These are often specified as BWG (Birmingham Wire Gauge) measurements. For instance, for 1-inch tube ODs, TEMA recommends a BWG range of between 12 (0.109 inch or 10.9% of OD) and 16 (0.065 inch or 6.5% of OD). For other tube ODs, the BWG range differs but these can also be presented as a percentage on the tube OD. Petro-SIM uses the tube pressure and material to set the minimum and maximum values. The values increase with tube pressure and reduce as more expensive tube material is used. Baffle Spacing (%) Specify the range of acceptable baffle spacing as a percentage of shell inner diameter. Shell Inner Diameter For industrial exchangers, the minimum Shell ID is about18 inches and the maximum shell ID varies depending on the shell rear end type. For floating tube sheet exchangers, the maximum practical shell ID is 60 inches but for other rear head types, up to 100 inches is allowed. Shell Aspect Ratio (L/D) Allowing small L/D ratios leads to more expensive exchangers overall and exchangers with high L/D ratios are likely to suffer from vibration. Enter the acceptable ranges. Geometry Options Use the Geometry Design, Geometry Options page to specify the range of tube and shell side parameters that you want Petro-SIM to evaluate when searching for suitable designs. v 565 Chapter 8: General Unit Operations The choice of which stream to place on the tube side involves a trade-off between many factors such as overall heat transfer coefficient, available pressure drops, fouling tendencies, and operating pressure. When choosing which stream to place on the tube side, specify the geometry options in these groups. Preference for Tube Side Allocation 566 v Parameter (From) Description Pressures The higher pressure fluid is normally placed on the tube side. With their small diameter and nominal wall thicknesses, tubes are preferred for placing high-pressure fluid so as to avoid designing the larger more expensive shell for high pressure. Exchangers are priced in pressure bands of 150 psi, 300 psi, 450 psi, 600 psi, and higher. If pressure of the hot stream falls within the same band as the cold stream, then neither side is given any preference for tube-side placement. The stream whose pressure falls in a higher pressure band is preferred for tube side placement from pressure consideration. Materials The main factors for choosing the materials of construction are corrosion and temperatures. Special alloys are often required to mitigate the risk of corrosion and such exotic materials are also required to cope with the risk of thermal shock when handling high-temperature streams. As these materials are expensive, it is cheaper to place the corrosive fluid on the tube side so that the shell side can avoid corrosive fluid that requires the expensive material. The side with the more expensive material is thus preferred for tube side placement when considering the material of construction. Fouling It is easier to achieve high velocities in the tubes which minimizes the rate Heat Exchanger Parameter (From) Description of fouling deposit. Also, it is easier to clean exchanger tubes with mechanical methods. Consequently, the higher fouling fluid is preferred for tube side placement. Recommendation The three factors listed for tube side factor may lead to conflicting decisions about whether the hot stream or the cold stream should be placed on the tube side. Petro-SIM uses weighting factors to determine the overall decision for tube side placement. The stream with the higher weighting is finally recommended for placement on the tube side. Weighting The recommendation for tube side allocation is not a definitive statement but is simply a guideline as to what would be preferable based on those considerations. Petro-SIM uses the qualitative weighting values to indicate how weak or strong the recommendation is. Choice Select which option to fix the tube side allocation or allow Petro-SIM to consider placing either the hot or cold stream on the tube side (Try Both). Tube Side Geometry Parameter Description Tube Length Check any combination of the tube lengths that you want to be considered in the comparison of designs for heat exchanger service to minimize the cost of manufacturing the exchangers. You cannot select 32-, 36-, or 30foot tubes if P, S, T, or W rear head types are used. Tube OD Check the tube outer diameters that you want to consider. For mechanical cleaning, the minimum tube OD is 0.75 inches. v 567 Chapter 8: General Unit Operations Shell Side Geometry Parameter Description Fixed Rear Head Fixed tubesheet types are the least expensive but they are not suitable when there is a large temperature difference between the hot and cold stream because of the risk of stress failure caused by thermal expansion. Also, the shell side can only be cleaned mechanically. As a result, fixed tubesheet types only become enabled when the temperature difference is less than 60°C and chemical cleaning method is specified. If fixed tubesheet exchangers are suitable, Petro-SIM selects type L by default, but you can change this to type M or N. U Tube U tubes are only slightly more expensive than fixed tubesheet exchangers, and are considered if chemical cleaning or U-tube mechanical cleaning is specified. Floating Rear Head Used for large temperature differences and mechanical cleaning. Floating tubesheet exchangers are up to 25% more expensive than fixed tubesheet exchangers but are suitable for most situations. As a result, floating tubesheet exchangers are always enabled. By default, Petro-SIM select type S when the stream pressures are below 545 psi, and type T when either of the pressures is 545 psi or higher. This is because the risk of contamination is increased at high pressures. Recommended Type The recommended end type is displayed. TEMA Type The TEMA type combines the front head type, shell type, and rear head type. Petro-SIM automatically selects the front head type that corresponds to the head type that is recommended above. TEMA Shell Type E shells are considered in all cases, unless removed from the selection. If the temperature cross is greater than 5°C, Petro-SIM automatically selects the F shell, but you can de-select it, if required. Also, J-shells are checked if the allowable pressure drop is less than or equal to 0.2 bar per shell. Baffle Type Choose from three types of segmented baffles and two types of helical baffles. The single segmented baffles are the most efficient for heat transfer so are chosen by default. Helical (single helix) baffles are able to achieve high shell side velocities at low pressure drops and are therefore good candidates for mitigating fouling in high viscosity fluids. Baffle Cut / Helix Angle If segmented baffle types are selected, then specify the range for the baffle cuts and step size. If helical baffles are selected, then specify the range for the helix angles and 568 v Heat Exchanger Parameter Description step size, instead. Tube Layout Petro-SIM selects 45° by default to facilitate cleaning, but you can modify the angle as required. Tube Pitch Ratio You cannot change the minimum tube pitch ratio of 1.25 nor the third value of 1.333, but you can change the value between them and you can change the maximum tube pitch ratio. Time Estimate Although Petro-SIM allows you to add any of the potential tube and shell dimensions in its consideration, increasing number of dimensions increases the time it takes for the tool to complete its search. Estimates show the upper values. Petro-SIM does not continue with calculations if the pressure drop or velocity constraints are violated. As a result, the number of calculations it finally performs will be much lower. Parameter Description Num. Designs Number of potential designs that are considered based on the geometry options selected. Estimated Time An estimate of the time that it takes to complete the search. Calculate The Geometry Design, Calculate page shows the status of calculations. Click Find Designs to start the calculations. Alternatively, click Initialize and Calculate on the Initialize page. v 569 Chapter 8: General Unit Operations To stop the calculations, click Cancel. Petro-SIM stops the search and reports the designs that it has found so far. Feedback Description Number of designs evaluated so far Displays how many of the designs that were calculated so far. Some designs are rejected because they do not meet the constraints. Percentage Completed Indicates the progress of the calculations as a percentage. Time taken so far. Actual time elapsed since the calculations started. Designs found so far Number of designs that satisfy the design constraints. The maximum number of designs that Petro-SIM stores and reports is 5000. If this limit is reached before all the options have been evaluated, Petro-SIM purges the designs by deleting the most expensive designs of the same geometries (that is, same Tube Length, Tube OD, Tube Thickness, Number of Shells in Parallel, Number of Shells in Series, Number of Tube Passes). It then continues to search for more designs until all options have been evaluated. As a result, the number of designs found may reduce as it approaches 5000, but the number builds up again. Designs The Geometry Design, Designs tab contains these pages: Results The Results page shows the designs that satisfy the process constraints. The designs are presented without warranties of any kind either express or implied. 570 v Heat Exchanger Because Petro-SIM can find up to 5,000 designs, this page provides a series of features for filtering and sorting the designs so that you can identify acceptable designs for further consideration. Parameter Description Num found The total number of designs that satisfy the constraints that were set on the Basis tab. Filter Select which designs you want to see from the drop-down lists .You can combine tubeside allocation with shell type (that is, Hot Tube E shells only). Sort By Sort the designs by using the primary and secondary parameter dropdown lists. Delete Rank Enter the manual ranking order value in the field and click Delete Rank to remove all designs that exceed the value that is unacceptable while retaining the other designs. Calc Time Approximate time to complete the calculations. Original design Status of the original design in relation to the constraints specified on the Basis tab. If the status is not OK, details are provided in on the Design Summary page. Goto Select a design number to view its details. Bookmark Selected Result Check the Selected Design check box in the grid, and then click Bookmark Selected Result to add the design to the Bookmarked Designs page. You can bookmark a maximum of 20 designs. Apply Design Check the Selected Design check box in the grid, and then click Apply Design to copy the design to the main exchanger unit. The selected design data overwrites the original design. Cost Factor Enter the cost factor that you want to appy to all the relative costs for all the designs. Petro-SIM uses the factor to calculate the relative cost for each design. The default cost factor is the year 2000 purchase cost in US dollars and does not account for geographical differences in capital cost. The grid reports the following results for each design, including the original design. v 571 Chapter 8: General Unit Operations Result Description Sort Order The position of the design when the sort parameters are applied. Design The original position that the design was found. Allocation Indicates which stream is to be placed on the tube side. TEMA Type The three letter TEMA designation describing the front head, shell type, and rear head. Selected Design Check this box to select which exchanger to bookmark or apply. Refer to Bookmark Selected Result or Apply Design in previous table. Manual Ranking Order Change the ranking order to change the sort order for the exchangers. Petro-SIM re-orders the designs when you select Manual Ranking Order as the primary sort parameter. Sort1 Displays the primary sort parameter. Sort2 Displays the secondary sort parameter. Total Heat Transfer Area Surface area of all the shells combined. Length over Diameter Tube Length divided by Shell diameter. Ratio HTC Ratio Indicates the level of similarity between the heat transfer coefficient on the shell side and the tube side. To ensure that the value is always greater than one, the denominator could be the shell side coefficient or the tube side coefficient. Oved Design with No Fouling This represents the overdesign in the exchanger when the fouling factor is set to zero on the shell side and on the tube side. This indicates how the exchanger will perform when it is completely clean and without rust. Shell Inside Diameter The shell inside diameter rounded up to the nearest inch to facilitate fabrication. 572 v Baffle Spacing [%] Baffle Spacing, displayed as a percentage of Shell Inside Diameter. Helix OverLap [%] If the Baffle Type is single- or double-helix, the helix overlap is displayed instead of the baffle spacing. Tube Thickness by OD [%] Tube thickness as a percentage of the Tube OD. Tube Thickness Tube thickness in small length units. Tube Thickness Tube thickness in BWG measurement. Heat Exchanger Result Description [BWG] Tube Pitch Ratio Ratio of the Tube Pitch to the Tube Outer Diameter. Relative Cost Relative cost for each design as a function of surface using a correlation8 that applies correction factors for tube length, material of construction, design pressure, and rear head type. The other results on the table are the same as described under the Rating, Sizing page. Plots The Plots page displays a graphical trend of the exchanger parameters. 1. To change the parameters that you want to plot, click Edit Plot. 2. In the Plot Choices for Geometry Design view, select or de-select the parameters you want plotted. v 573 Chapter 8: General Unit Operations 3. To begin the plot at a selected design, select the design number from the Goto drop-down. 4. To reduce the number of designs displayed on the plot, enter a number in the Num to show field. 5. Optionally, check Plot as percentages to display the values as percentages of the highest value observed for the corresponding parameter. 6. Check Show original design to show the data for the original design. Uncheck to hide the data so as not to distort the scale of the graph. 7. To view the details of a design plotted on the graph, hover your cursor over a coordinates on the graph. the Design Structure updates to show the details. For more information about graphs, refer to Graph Control. 574 v Heat Exchanger Design Summary The Design Summary page describes the basis for the current geometry design session and a summary of the results, including the status of the original design. Use the editing tools to modify the summary. To print the summary, right-click the background and choose Print. Bookmarked Designs The Bookmarked Designs page lists all designs that you have saved and bookmarked on the Results or Plots pages. This page enables you to review or print selected designs at a later date. In addition, Petro-SIM automatically adds the Cheapest and Simplest Hot and Cold Tube designs as well as a recommended design to the list. You can store a maximum of 20 designs. In identifying the recommended design, Petro-SIM takes the following considerations into account. v 575 Chapter 8: General Unit Operations l l l l l Tube Side Allocation: If the weighting for the Tube Side Allocation as shown on the Geometry Options tab is Strong or Medium, Petro-SIM will commit to this in its recommendation. If the weighting is weak, Petro-SIM will give priority to other parameters like cost or overdesign. Relative Cost or Over Design: New designs are sorted in ascending order of Relative Cost and Tube Rebundling designs are sorted in descending order of overdesign. Number of shells: The function used to determine the relative cost considers surface area but does note account of the number of shells that the area is spread over. In recommending a design, Petro-SIM uses weighting factors to give preference to exchangers with fewer shells in series or parallel and fewer tube passes. The factors are set to prefer shells in parallel above shells in series because shells in parallel have the advantage of permitting one shell to be taken out for cleaning while the other shell remains in service. The factors are applied to the relative cost such that designs with 2 shells in parallel will appear cheaper than those with 2 shells in series. Tube OD: If the fouling factor for the tube side fluid is >= 0.004 F.hr.ft2/Btu, preference will be given to tubes of 1.0 in OD and higher. Tube Length: Preference is given to 20ft tube exchangers. Check Select Design to select the design and then click Apply Bookmarked Design to apply the design to the heat exchanger Rating tab. To remove a design, select it and then click Remove from bookmark. 576 v Air Cooler Air Cooler The Air Cooler unit operation uses an ideal air mixture as a heat transfer medium to cool (or heat) an inlet process stream to a required exit stream condition. One or more fans circulate the air through bundles of tubes to cool process fluids. The airflow can be specified or calculated from the fan rating information. Pressure drop can also be determined. 1. To add an Air Cooler to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Air Cooler (or click and drag it to the flowsheet). An Air Cooler is added to the active flowsheet. 3. In the Air Cooler Property view, enter the Air Cooler properties in these tabs: l l l l l Design Rating Worksheet Performance Dynamics - This tab is available only when working in Dynamics mode. 4. To ignore the Air Cooler during calculations, check Ignored. Design Modify the Air Cooler Design tab settings on these pages: v 577 Chapter 8: General Unit Operations Connections Use the Connections page to specify the feed and product streams attached to the Air Cooler. You can change the name of the operation in the Name field. Parameters Use the Parameters page to modify these Air Cooler parameters: 578 v Air Cooler Parameters Description Delta P The pressure drops (DP) for the process side of the Air Cooler can be specified. The pressure drop can be calculated if both the inlet and exit pressures of the process stream are specified. There is no pressure drop associated with the air stream. The air pressure through the Cooler is assumed to be atmospheric. UA The product of the Overall Heat Transfer Coefficient and the Total Area available for heat transfer. The Air Cooler duty is proportional to the log mean temperature difference, where UA is the proportionality factor. The UA can either be specified or calculated by Petro-SIM. Configuration Displays the possible tube pass arrangements in the Air Cooler. There are seven different Air Cooler configurations to choose from. Petro-SIM determines the correction factor, Ft, based on the Air Cooler configuration. Inlet/Exit Air Temperatures The inlet and exit air stream temperatures can be specified or calculated by Petro-SIM. You can also add User Variables and Notes. Rating The Air Cooler Rating tab contains these pages: Sizing Use the Sizing page to specify the fan rating information. v 579 Chapter 8: General Unit Operations Fan Data Description Number of Fans The number of fans in the Air Cooler. Speed The actual speed of the fan in rpm (rotations per minute). Demanded Speed The desired speed of the fan. The demanded speed always equals the speed of the fan. The desired speed is either calculated from the fan rating information or user specified. Max Acceleration Not used in Petro-SIM. Design Speed The reference Air Cooler fan speed. It is used in the calculation of the actual air flow through the Cooler. Design Flow The reference Air Cooler air flow. It is used in the calculation of the actual air flow through the Cooler. Current Air Flow This can be calculated or user-specified. If the air flow is specified no other fan rating information needs to be specified. The air flow through the fan is calculated using a linear relation: Fan Air Flow = Speed x Design Flow Design speed Each fan in the Air Cooler contributes to the air flow through the Cooler. The total air flow is calculated as follows: Total Air Flow =ΣFan Air Flow Nozzles Use the Nozzles page to enter the elevation, if applicable, and define the nozzle parameters. 580 v Air Cooler Performance The Air Cooler Performance tab contains pages that display the results of the Air Cooler calculations. v 581 Chapter 8: General Unit Operations Results Result Description Working Fluid Duty This is defined as the change in duty from the inlet to the exit process stream: LMTD Correction Factor, Ft The correction factor is used to calculate the overall heat exchange in the Air Cooler. It accounts for different tube pass configurations. UA The product of the Overall Heat Transfer Coefficient and the Total Area available for heat transfer. The UA can either be specified or calculated by Petro-SIM. LMTD The LMTD is calculated in terms of the temperature approaches (terminal temperature difference) in the exchanger, using the uncorrected LMTD equation: Hprocess, in + Duty = Hprocess, out ∆TLM = ∆T1 − ∆T2 ln(∆T1 / (∆T2 )) where: ΔT =T -T 1 hot, out cold, in ΔT =T -T 2 hot, in cold, out Inlet/Exit Process Temperatures The inlet and exit process stream temperatures can be specified or calculated in Petro-SIM. Inlet/Exit Air Temperatures The inlet and exit air stream temperatures can be specified or calculated in Petro-SIM. Total Air flow The total air flowrate displays in volume and mass units. Profiles The Profiles page is available when working in Dynamics mode. Refer to Air Cooler - Dynamics for more information. 582 v Air Cooler Air Cooler Theory The Air Cooler uses the same basic equation as the Heat Exchanger unit operation. The Air Cooler operation can calculate the flow of air based on the fan rating information. The Air Cooler calculations are based on an energy balance between the air and process streams. For a cross-current Air Cooler, the energy balance is shown as follows: M air(H out − Hin )air = M process(H in − H out)process where: M air = air stream mass flow rate M process = process stream mass flow rate H = enthalpy The Air Cooler duty, Q, is defined in terms of the overall heat transfer coefficient, the area available for heat exchange and the log mean temperature difference: Q = −UA ∆T LM Ft where: U = overall heat transfer coefficient A = surface area available for heat transfer ΔT LM = log mean temperature difference (LMTD) F = correction factor t v 583 Chapter 8: General Unit Operations The LMTD correction factor, Ft, is calculated from the geometry and configuration of the Air Cooler. Pressure Drop The pressure drop along a stream in a Air Cooler unit operation can be determined in one of two ways: l l Specify the pressure drop. Define a pressure flow relation in the Air Cooler by specifying a K value. If the pressure flow option is chosen for pressure drop determination in the Air Cooler unit operation, a K value is used to relate the frictional pressure loss and flow through the Air Cooler. This relation is similar to the general valve equation: flow = density * k P 1 − P 2 This general flow equation uses the pressure drop across the Air Cooler without any static head contributions. The quantity, P1 - P2, is defined as the frictional pressure loss that is used to “size” the Air Cooler with a K value. 584 v Pump Pump The Pump unit operation is used to increase the pressure of an inlet liquid stream. Depending on the information specified, the Pump operation calculates either an unknown pressure, temperature, or pump efficiency. Refer to Pump Theory for more details on calculations. 1. To add a Pump to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Pump (or click and drag it to the flowsheet). A Pump is added to the active flowsheet. 3. In the Pump Property view, enter the Pump properties in these tabs: l Design l Rating l Worksheet l Performance l Dynamics - This tab is available only when working in Dynamics mode. If you are working in Steady State mode, you are not required to change any of the values on the Dynamics tab. 4. To activate the Pump, select the On check box. You can then specify a pressure rise, or the pressures of the inlet stream and outlet stream. If the pump is deactivated, Petro-SIM passes the inlet stream unchanged; that is, the outlet stream is exactly the same as the inlet stream. v 585 Chapter 8: General Unit Operations If you specify a Delta P, this value is ignored when you turn the Pump off. If you specify the pressures of the inlet stream and outlet stream, you get a consistency error when you turn the Pump off, because the inlet stream conditions pass to the outlet stream. 5. To ignore the Pump during calculations, check Ignored. Design The Pump Design tab consists of these pages: Connections Use the Connections page to specify the inlet stream, outlet stream and energy stream attached to the Pump. Parameters You can specify the adiabatic (same as "isentropic") efficiency, Delta P and pump energy (power) parameters on the Parameters page. 586 v Pump You can specify both the inlet stream pressure and outlet stream pressure, in which case PetroSIM calculates Delta P. Alternatively, you can specify one stream pressure and a Delta P value; in this case, the other stream pressure is calculated by Petro-SIM. Curves The Curves page lets you specify a pump curve. If you want to specify a pump curve: 1. Enter the coefficients for the polynomial pump equation, as well as the units for pressure and flow. 2. Check the Activate Curves check box. Petro-SIM determines the pressure rise across the Pump for the given flow rate. v 587 Chapter 8: General Unit Operations To avoid a consistency error, ensure you have not specified the pressure rise across the Pump, either in the attached streams or in the operation itself. Links In Petro-SIM, Pumps can have physically connected shafts. A list of available Pumps can be displayed by clicking the Downstream Link drop-down list. It is not significant which order the Pumps are linked. The notion of upstream and downstream links is arbitrary and determined by you. Linked Pump operations require curves. Usually, the total power loss from the linked operations is specified. For a series of linked Pumps, it is desired to input a total power: Total Power Input = − Total Power Loss Total power loss or input to the linked Pump operations can be specified by you in the Total Power Loss field. It is possible to link a Pump to a Compressor and use the Pump as a turbine to generate kinetic energy to drive the Compressor. If this option is selected, the total power loss is typically specified as zero. You can also add User Variables and Notes. Rating The Pump Rating tab is only available in Dynamics mode. It contains these pages: Curves Use the Curves page to plot and view curves for the pump. 588 v Pump Click... To... View Curve View the properties for a selected curve. Add Curve Add a new curve to the pump in the PumpCurve view. Delete Curve Remove a curve from the pump. Plot Curves Open the Pump Curves Profiles view where you can view the pump flow rate on a plot diagram. Refer to Graph Control for information on plots. NPSH The NPSH page is available only in Dynamics mode. Nozzles Use the Nozzles page to enter the pump elevation and nozzle parameters, if applicable. v 589 Chapter 8: General Unit Operations Inertia Use the Inertia page to enter the Radius of Gyration and Mass parameters. Startup Enter the Typical operating capacity on the Design Flow page. Performance The Pump Performance tab consists of the Results page which displays the pump head information. The values for Total head, Pressure head, Velocity head and Delta P excluding static head are calculated values. The Total head field is used only for dynamic simulation. 590 v Pump Pump Theory The calculations for the Pump unit operation are based on the standard pump equation for power, which uses the pressure rise, the liquid flow rate and density: Power Requiredideal = (Pout − P in ) * Flow Rate Liquid Density where: P out = pump outlet pressure P = pump inlet pressure in The above equation defines the ideal power needed to raise the liquid pressure. The actual power requirement of the Pump is defined in terms of the Pump Efficiency: Efficiency(%) = Power Required ideal Power Requiredactual * 100 % When the efficiency is less than 100%, the excess energy goes into raising the temperature of the outlet stream. Combining the above equations leads to the expression for the actual power requirement of the Pump: Power Requiredactual = (Pout − P in ) * Flow Rate*100% Liquid Density*Efficiency(%) Finally, the actual power is equal to the difference in heat flow between the outlet and inlet streams: Power Requiredactual = (Heat Flowoutlet − Heat Flowinlet ) If the feed is fully defined, only two of the variables need to be specified for the Pump to calculate all unknowns: l l l Outlet Pressure or Pressure Drop Efficiency Pump Energy Petro-SIM can also back-calculate the inlet Pressure. For a pump, an efficiency of 100% does not correspond to a true isentropic compression of the liquid. Pump calculations are performed by Petro-SIM with the assumption that the liquid is incompressible, that is, the density is v 591 Chapter 8: General Unit Operations constant (liquid volume is independent of pressure). This is the usual assumption for liquids well removed from the critical point and the standard pump equation given above is generally accepted for calculating the power requirement. If you want to perform a more rigorous calculation for pumping a compressible liquid (that is, one near the critical point), you should instead install a compressor to represent the pump. If you choose to represent a Pump by installing a Compressor in Petro-SIM, the power requirement and temperature rise of the Compressor is always greater than those of the Pump (for the same fluid stream), because the compressor treats the liquid as a compressible fluid. When the pressure of a compressible fluid increases, the temperature also increases and the specific volume decreases. More work is required to move the fluid than if it were incompressible, exhibiting little temperature rise, as is the case with a Petro-SIM Pump. The ideal power required, W, to increase the pressure of an incompressible fluid is: W= (P 2 − P 1)F (MW ) ρ where: P = pressure of the inlet stream 1 P = pressure of the exit stream 2 ρ = density of the inlet stream F = molar flow rate of the stream MW = molecular weight of the fluid For a Pump, it is assumed the entering liquid stream is incompressible. Therefore, the ideal work defined in the above equation does not correspond to a true isentropic compression of the liquid. Despite this, the pump efficiency is defined in terms of the ideal work and not the isentropic work. 592 v Compressor or Expander Compressor or Expander The Compressor unit operation is used to increase the pressure of an inlet gas stream with relative high capacities and low compression ratios. Depending on the information specified, the Compressor calculates either a stream property (pressure or temperature) or a compression efficiency. Petro-SIM supports two types of compressors: centrifugal and reciprocating. In general, procedures apply to both types except where explicitly stated. For information about compressors or expanders, refer to Compressor and Expander Theory and Typical Solution Methods. For specific information about reciprocating compressors, refer to Reciprocating Compressors and Reciprocating Compressor Theory. The Expander unit operation is used to decrease the pressure of a high-pressure inlet gas stream to produce an outlet stream with low pressure and high velocity. An expansion process involves converting the internal energy of the gas to kinetic energy and finally to shaft work. The Expander calculates either a stream property or an expansion efficiency. 1. To add a Compressor or Expander to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double click Compressor or Expander (or click and drag it to the flowsheet). A Compressor or Expander is added to the flowsheet. v 593 Chapter 8: General Unit Operations Compressor property view Expander property view 3. Enter the properties in these tabs: l Design l Rating l Worksheet l Performance 4. To ignore the Compressor or Expander during calculations, check Ignored. 594 v Compressor or Expander There are several methods for the Compressor or Expander to solve, depending on what information has been specified and whether or not you are using the compressor’s characteristic curves. The operating characteristics curves of a Compressor are usually expressed as a set of polytropic head and efficiency curves made by manufacturers. In general, the solution is a function of flow, pressure change, applied energy and efficiency. The Compressor or Expander provides a great deal of flexibility with respect to what you can specify and what it then calculates. Ensure you do not enable too many of the solution options or inconsistencies may result. Refer also to Hydraulic Turbine. Design The Compressor or Expander Design tab contains these pages: Connections Use the Connections page to specify the name of the operation, the inlet stream, outlet stream, and energy stream. The figure shows the Connections page for the Compressor property view. The information required on the Connections page is identical for the Expander. v 595 Chapter 8: General Unit Operations Parameters Use the Parameters page specify the duty of the attached energy stream, or let Petro-SIM calculate it. For the Compressor, in the Operating Mode group, select either: l l Centrifugal - to set up a centrifugal compressor, follow these basic procedures. Reciprocating - for more information about setting up a reciprocating compressor, refer to Reciprocating Compressor/ Compressor property view 596 v Compressor or Expander Expander property view The Adiabatic and Polytropic efficiencies appear on this page as well. You can specify only one efficiency, either adiabatic or polytropic. If you specify one efficiency and a solution is obtained, Petro-SIM back calculates the other efficiency, using the calculated duty and stream conditions. Links Compressors and Expanders modelled in Petro-SIM can have shafts that are physically connected to the unit operation. Linking compressors and Expanders in Petro-SIM means the: l l l Speed of each linked unit operation is the same. Sum of duties of each linked Compressor or Expander usually equals zero. Total power loss usually equals zero. The Total Power Loss is shown on the Links page. It is not significant which order the Compressors or Expanders are linked. The notion of upstream and downstream links is arbitrary and determined by you. v 597 Chapter 8: General Unit Operations A list of available compressors or expanders can be displayed by clicking the down arrow in the Upstream Link field or Downstream Link field. In most cases, one additional specification for any of the linked operations is required to allow the simulation case to completely solve. Ideally, you should specify one of the following for any of the linked unit operations. l l l Duty Speed Total Power Loss Usually, total power input to the linked compressors or expanders is calculated in a Spreadsheet operation and specified in the Total Power Loss field. If you want to provide the total power input to a set of linked compressors or expanders, the total power input to the linked operations is defined in terms of a total power loss. The relationship is: Total Power Input = - Total Power Loss It is also possible to link an Expander to a Compressor and use the Expander to generate kinetic energy to drive the compressor. If this option is chosen, the Total Power Loss is typically specified as zero. Operating Limits The Operating Limits page allows the user to enter a minimum or maximum value for different variables. The user can also specify whether a warning (yellow) or Error (red) status is displayed. 598 v Compressor or Expander Settings - Reciprocating Compressors only The Settings page is used to size the Reciprocating Compressor. The Settings page is only visible when you have activated the Reciprocating Compressor option from the Design tab, Parameters page. v 599 Chapter 8: General Unit Operations A Reciprocating Compressor does not require a characteristic curve. The following compressor geometry information is required: l l l l l l l l l l l Number of Cylinders Cylinder Type Bore - Diameter of the cylinder. Stroke - Distance head of piston travels. Piston Rod Diameter Constant Volumetric Efficiency Loss Default Fixed Clearance Volume Zero Speed Flow Resistance (k) - dynamics only Typical Design Speed - Typical Design Speed is the estimated speed for the rotor. Volume Efficiency Speed - Speed is the actual speed of the rotor. Depending on the cylinder type selected, you have 4 additional parameters that can be specified. If the cylinder type is of double action, you need to specify the fixed clearance volume for the crank side and the outer side. l l l l Fixed Clearance Volume Variable Clearance Volume Variable Volume Enabled Cylinder is Unloaded - dynamics only If the Variable Volume Enabled check box is selected, you need to specify a variable clearance volume. The variable clearance volume is used when additional clearance volume (external) is intentionally added to reduce cylinder capacity If the Cylinder is Unloaded check box is selected, the total displacement volume is not considered and is essentially zero. Click Size k... to specify a pressure drop and mass flow rate in the Reciprocating Pressure-Flow Sizing view. Size k is used to calculate the zero speed flow resistance of the Reciprocating Compressor. 600 v Compressor or Expander You can also add User Variables and Notes. Rating The Compressor or Expander Rating tab contains these pages: Curves You can specify one or more Compressor or Expander curves on the Curves page. These curves are part of the default Performance Map when the Multiple Curve Type is Performance Map. The Molecular Weight (MW)and Inlet Guide Vane (IGV) options will be explained below. The Curves page applies only for centrifugal compressors and is not required for a reciprocating compressor. If you specify curves, ensure the efficiency values on the Parameters page are empty or a consistency error is generated. You can create adiabatic or polytropic plots for values of efficiency and head. The efficiency and head for a specified speed can be plotted against the capacity of a Centrifugal Compressor or Expander. Multiple curves can be plotted to show the dependence of efficiency and head on the speed of Centrifugal Compressors or Expanders. If you do not use curves, specify four of the following variables and the fifth is calculated, along with the duty: l l Inlet Temperature Inlet Pressure v 601 Chapter 8: General Unit Operations l l l Outlet Temperature Outlet Pressure Efficiency You can also specify duty as one of the four specifications, but not with every combination of the above. Specify data for curves 1. Check Enable Curves. 2. Select either an Adiabatic or Polytropic efficiency to determine the basis of your input efficiency values. The efficiency type must be the same for all input curves. 3. To add a curve, click Add Curve. 4. In the Curve view, enter the following information: Curve Data Description Name Name of the curve. Speed The rotational speed of the Centrifugal Compressor or Expander. This is optional if you specify only one curve. Flow Units/Head Units Units for the flow and head. Flow/Head/Efficiency Enter any number of data points for the curve. To delete a selected row of the flow, head or efficiency data, click.Erase Selected. To delete all flow, head and efficiency data, click Erase All. 5. When you are done adding data for the curve, close the view to return to the Curves page. 6. For each additional curve, repeat steps 3 - 5. 602 v Compressor or Expander 7. When you are done, check the associated Active? check box to activate or deactivate individual curves. Petro-SIM can interpolate values for the efficiency and head of the Centrifugal Compressor or Expander for speeds that are not plotted. If compressors or expanders are linked, it is a good idea to ensure that the curves plotted for each unit operation span a common speed and capacity range. Typical curves are plotted below. For an Expander, the head is only zero when the speed and capacity are zero. Single Curve When you have a single curve, the combinations of input allow the operation to completely solve (assuming the feed composition and temperature are known): v 603 Chapter 8: General Unit Operations l l l l Inlet Pressure and Flow Rate Inlet Pressure and Duty Inlet Pressure and Outlet Pressure Inlet Pressure and Efficiency corresponding to the Curve type (e.g. if the Curve is Adiabatic, provide an Adiabatic Efficiency). Multiple Curves If multiple curves have been installed and an operating speed is specified on the Parameters page, then only the curve with the corresponding speed is used. You can specify a speed that is different than the speeds given for the curves. For example, if you provide curves for two speeds (1000/min and 2000/min) and you specify a speed of 1500/min, Petro-SIM interpolates between the two curves to obtain the solution. You must also provide an inlet pressure and one of the variables: flow rate, duty, outlet pressure, or efficiency. Petro-SIM can calculate the appropriate speed based on your input. In this case, you need to provide the feed composition, pressure and temperature as well as two of the following variables: l l l l Flow rate Duty Efficiency Outlet Pressure Once you provide the necessary information, the appropriate speed is determined and the other two variables are then calculated. View the Performance Map Click Performance Map to display the Efficiency Contour lines of the compressor along with the Surge and Stonewall curves if provided. If a surge controller has been activated, the Control line is also included on the plot. 604 v Compressor or Expander Add Performance Maps If you want to try out a different set of curves, click Add PM to add another Performance map. Enter curves for that Performance Map and activate it by checking the cell in the Active? column. Multiple Curve Collections Molecular Weight (MW) Curve Collections If you select Molecular Weight as the Multiple Curve Type, enter curves for each of the MW collections that you want to plot. Enter the Curve MW for each collection. Petro-SIM interpolates a solution based on the curves provided. v 605 Chapter 8: General Unit Operations Inlet Guide Vane (IGV) Curve Collections If you select Inlet Guide Vane as the Multiple Curve Type, enter curves for each of the IGV collections that you want to plot. Enter the Curve IGV for each collection. Petro-SIM interpolates a solution based on the curves provided.. Flow Limits You can specify surge and/or stonewall curves for your Performance Map(s) as well as for each MW or IGV collection. Selecting the Performance Maps/MW Curve Collections/IGV Curve Collections on the right determines which curve you can view when you click either Surge Curve or Stonewall Curve. The current Surge, Feed, and Stonewall flows are displayed in the Current Flows matrix. To create or view the surge controller, click Create/View Surge Controller. The surge controller allows you to control the flow of the compressor to make sure it does not go into a surge condition. 606 v Compressor or Expander To set up the surge controller, select the Target Object (the stream you would like to manipulate) on the Connections tab. Select the Parameters tab.to change the Control Line % and the Maximum Number of Iterations on v 607 Chapter 8: General Unit Operations A Centrifugal Compressor can also be used to represent a Pump operation when a more rigorous pump calculation is required. The Pump operation in Petro-SIM assumes that the liquid is incompressible. Therefore, if you want to pump a fluid near its critical point (where it becomes compressible), you can do so by representing the Pump with a Centrifugal Compressor. The Centrifugal Compressor operation takes into account the compressibility of the liquid, thus performing a more rigorous calculation. Performance Tab The Performance tab consists of only the Results page which displays a table of calculated values for the Compressor or Expander: l l l l l l l l l l l l l l l Adiabatic Head Polytropic Head Adiabatic Efficiency Polytropic Efficiency Duty Polytropic Head Factor Polytropic Exponent Isentropic Exponent Speed Duty Loss Total Effective Piston Displacement Volume Total Effective Fractional Clearance Volume Maximum Pressure Ratio Lead in Compression Load in Tension Compressor and Expander Theory For a Compressor, the isentropic (or adiabatic) efficiency is given as the ratio of the isentropic (ideal) power required for compression to the actual power required: Efficiency(%)= Power Required isentropic Power Requiredactual * 100 % For an Expander, the efficiency is given as the ratio of the actual power produced in the expansion process to the power produced for an isentropic expansion: 608 v Compressor or Expander Efficiency(%)= Fluid Power Requiredactual Fluid Power Required isentropic * 100 % For an adiabatic Compressor and Expander, Petro-SIM calculates the centrifugal compression (or expansion) rigorously by following the isentropic line from the inlet to outlet pressure. Using the enthalpy at that point, as well as the specified efficiency, Petro-SIM then determines the actual outlet enthalpy. From this value and the outlet pressure, the outlet temperature is determined. For a polytropic Compressor or Expander, the path of the fluid is neither adiabatic nor isothermal. For a 100% efficient process, there is only the condition of mechanical reversibility. For an irreversible process, the polytropic efficiency is less than 100%. Depending on whether the process is an expansion or compression, the work determined for the mechanically reversible process is multiplied or divided by an efficiency to give the actual work. The form of the polytropic efficiency equations are the same as the two above equations. Notice that all intensive quantities are determined thermodynamically, using the specified Property Package. In general, the work for a mechanically reversible process can be determined from: W = ∫V dP where: W = work V = volume dP = pressure difference As with any unit operation, the calculated information depends on the information that you specify. In the case where the inlet and outlet pressures and temperatures of the gas are known, the ideal (isentropic) power of the Operation is calculated using one of the above equations, depending on the Compressor or Expander type. The actual power is equivalent to the heat flow (enthalpy) difference between the inlet and outlet streams. For the Compressor: Power Requiredactual = Heat Flowoutlet − Heat Flowinlet where the efficiency of the Centrifugal Compressor is then determined as the ratio of the isentropic power to the actual power required for compression. For the Expander: Power Produced actual = Heat Flowinlet − Heat Flowoutlet v 609 Chapter 8: General Unit Operations The efficiency of the Expander is then determined as the ratio of the actual power produced by the gas to the isentropic power. In the case where the inlet pressure, the outlet pressure, the inlet temperature and the efficiency are known, the isentropic power is once again calculated using the appropriate equation. The actual power required by the Centrifugal Compressor (enthalpy difference between the inlet and outlet streams) is calculated by dividing the ideal power by the compressor efficiency. The outlet temperature is then rigorously determined from the outlet enthalpy of the gas using the enthalpy expression derived from the property method being used. For an isentropic compression or expansion (100% efficiency), the outlet temperature of the gas is always lower than the outlet temperature for a real compression or expansion. Efficiencies Compressor Efficiencies The Adiabatic and Polytropic Efficiencies are included in the Compressor calculations. An isentropic flash (P and Entropy ) is performed internally to obtain the ideal (isentropic) properties. in in Isentropic or Adiabatic Work Required (ideal) = Work Required (actual) (H out − H in )(ideal) (H out − H in )(actual) Polytropic  P  out  P in  ( n n−1 ) − 1 *  ( )   ( ) * ( ) n k −1 k  n − 1  k −1   P out  k  − 1 P in  ( )  where n= ( log 610 v P out ( ) log P in ρ out,actual ρ in ) * AdiabaticEff Compressor or Expander P out ( ) log k= ( log P in ρ out,ideal ρ in ) Expander Efficiencies For an Expander, the efficiencies are parts of the Expander calculations and an isentropic flash is performed as well. The flash is done on the Expander fluid and the results are not stored. Isentropic or Adiabatic Work Produced (actual) Work Produced (ideal) = (H out − H in )(actual) (H out − H in )(ideal) Polytropic  k −1       P out  k  − 1  P in    n −1   n n − 1 *  *   n −1   ( ) P out ( ( ) P in ) k −1 k     * AdiabaticEff ( ) ( ) where P out ( ) log n= ( log P in ρ out,actual ρ in ) P out ( ) log k= ( log P in ρ out,ideal ρ in ) where: H = mass enthalphy out = product discharge in = feed stream P = Pressure ρ = mass density v 611 Chapter 8: General Unit Operations n - polytropic exponent k = isentropic exponent Compressor and Expander Heads Compressor Heads The Adiabatic and Polytropic Heads are performed after the Compressor calculations are completed, only when the Results page of the Compressor is selected. The Work Required (actual) is the compressor energy stream (heat flow). The Polytropic Head is calculated based on the ASME method The Polytropic Analysis of Centrifugal Compressors.1 Adiabatic Work Produced (actual) Mass Flow Rate * AdiabaticEff * 1 g / ( gc ) Polytropic  n   Pout   P in  1 f* *  −   *    n − 1   ρout,actual   ρ in  g / gc )  (    where f= Hout,ideal − H in  k   P out   k − 1  *  ρ out,ideal  −     P in ρ in P out ( ) log n= ( log P in ρ out,actual ρ in ) P out ( ) log k= ( ) ( log P in ρ out,ideal ρ in ) 1Journal of Engineering for Power, J.M. Schultz, January 1962, p. 69-82). 612 v Compressor or Expander Expander Heads The Adiabatic and Polytropic Heads are performed after the Expander calculations are completed, only when the Results page of the Expander is selected. The Work Produced (actual) is the Expander energy stream (heat flow). Adiabatic Work Produced (actual) Mass Flow Rate * AdiabaticEff * 1 (g / gc ) Polytropic  n   Pout   P in  1 −f *  *  −   *    n − 1   ρout,actual   ρ in  g / gc )  (    where f= Hout,ideal − H in  k   P out   k − 1  *  ρ out,ideal  −     ( ) P in ρ in P out ( ) log n= ( log P in ρ out,actual ρ in ) P out ( ) log k= ( log P in ρ out,ideal ρ in ) where: H = mass enthalphy out = product discharge in = feed stream P = Pressure ρ = mass density n - polytropic exponent k = isentropic exponent v 613 Chapter 8: General Unit Operations Typical Solution Methods The thermodynamic principles governing the Compressor and Expander operations are the same, but the direction of the energy stream flow is opposite. Compression requires energy, while expansion releases energy. Petro-SIM calculates: Without Curves Scenario 1 Required energy, outlet 1. Flow rate and inlet pressure are known. temperature and other 2. Specify outlet pressure. efficiency. 3. Specify either Adiabatic or Polytropic efficiency. Scenario 2 1. Flow rate and inlet pressure are known. 2. Specify efficiency and duty. With Curves Outlet pressure, temperature and other efficiency. Petro-SIM calculates: Scenario 3 1. Flow rate and inlet pressure are known. 2. Specify operating speed. 3. Petro-SIM uses curves to determine efficiency and head. Outlet pressure, temperature and applied duty. Scenario 4 1. Flow rate, inlet pressure, and efficiency are known. 2. Petro-SIM interpolates curves to determine operating speed and head. Outlet pressure, temperature, and applied duty. Reciprocating Compressors A Reciprocating Compressor is used for applications where higher discharge pressures and lower flows are needed. It is known as a positive displacement type. Reciprocating Compressors have a constant volume and variable head characteristics, as compared to the Centrifugal Compressor that has a constant head and variable volume. To set up a Reciprocating Compressor, follow the procedures defined for Compressors and Expanders with the following exceptions: l l Enter the required information on the Design tab, Settings page. Reciprocating Compressors do not use a compressor curve. For Reciprocating Compressors there is no direct relationship between the head and flow capacity. 614 v Compressor or Expander The present capability of Reciprocating Compressors in Petro-SIM is focused on a single stage compressor with a single or double acting piston. A typical solution method for a Reciprocating Compressor is: l l l l Start with a fully defined inlet stream; for example, inlet pressure temperature, flow rate and compositional data are known. Specify compressor geometry data; for example,number of cylinders, cylinder type, bore, stroke and piston rod diameter. Petro-SIM provides default values. Specify compressor performance data; for example, adiabatic efficiency or polytropic efficiency and constant volumetric efficiency loss. Petro-SIM calculates the duty required, outlet temperature if the outlet pressure is specified. Reciprocating Compressor Theory A single stage Reciprocating Compressor consists of the basic components like the piston, the cylinder, head, connecting rod, crankshaft, intake valve and exhaust valve. Petro-SIM is capable of modelling a multi-cylinder in one Reciprocating Compressor with a single acting or double acting piston. A single acting compressor has a piston that's compressing the gas contained in the cylinder using one end of the piston only. A double acting compressor has a piston that is compressing the gas contained in the cylinder using both ends of the piston. The piston end that is close to the crank is called crank end, while the other is named the outer end. The thermodynamic calculations for a Reciprocating Compressor are the same as a Centrifugal Compressor. Basically, there are two types of compression being considered: l l Adiabatic/isentropic reversible path. A process during which there's no heat added to or removed from the system and the entropy remains constant, PVk=constant. Polytropic reversible path. A process in which changes in the gas characteristic during compression are considered. v 615 Chapter 8: General Unit Operations For more information about the operation of the Reciprocating Compressor, refer to Gas Processors Association1 . The performance of the Reciprocating Compressor is evaluated based on the volumetric efficiency, cylinder clearance, brake power and duty. Cylinder clearance, C is given as C= Sum of all clearance volume for all cylinders PD where: PD = positive displacement volume The sum of all clearance volume for all cylinders includes both fixed and variable volume. C is normally expressed in a fractional or percentage form. The piston displacement, PD is equal to the net piston area multiplied by the length of piston sweep in a given period of time. This displacement may be expressed as: For a single-acting piston compressing on the outer end only. π * D 2 * stroke 4 For a single-acting piston compressing on the crank end only. PD = PD = π * (D 2 − d 2) * stroke 4 For double-acting piston (other than tail rod type): PD = π * (2D 2 − d 2) * stroke 4 For a double-acting piston (tail rod type). PD = π * (2D 2 − 2d 2) * stroke 4 where: d = piston rod diameter D = piston diameter PD includes the contributions from all cylinders and both ends of any double acting. If a cylinder is unloaded then its contribution does not factor in. 1Gas Processors Association, Gas Processors Suppliers Association (1998) p.13-1 to p 13-20. 616 v Compressor or Expander The volumetric efficiency is one of the important parameters used to evaluate the Reciprocating Compressor’s performance. Volumetric efficiency, VE, is defined as the actual pumping capacity of a cylinder compared to the piston displacement volume. VE is given by:  1    ZS  Pd k       VE = 1 − L  − C − 1 Zd  PS          where: P = discharge pressure. d P = suction pressure. s L = effects of variable such as internal leakage, gas friction, pressure drop through valves and inlet gas preheating k = heat capacity ratio, Cp/Cv. Z = discharge compressibility factor. d Z = suction compressibility factor. s C = clearance volume To account for losses at the suction and discharge valve, an arbitrary value about 4% VE loss is acceptable. For a non-lubricated compressor, an additional 5% loss is required to account for slippage of gas. If the compressor is in propane, or similar heavy gas service, an additional 4% should be subtracted from the volumetric efficiency. These deductions for non-lubricated and propane performance are both approximate and if both apply, cumulative. Thus, the value of L varies from (0.04 to 0.15 or more) in general. Rod Loading Rod loads are established to limit the static and inertial loads on the crankshaft, connecting rod, frame, piston rod, bolting and projected bearing surfaces. v 617 Chapter 8: General Unit Operations It may be calculated as: Load in compression, L c Lc = Pd A p − Ps (A p − A r ) Load in tension, L t Lt = Pd (A p − A r ) − Ps A p Maximum Pressure The maximum pressure that the Reciprocating Compressor can achieve is: Pmax = Ps PRmax where the maximum discharge pressure ratio, PR max Z PRmax =  d (1 − L − VE + C )  Zs * C  is calculated from: k Flow Flow into the Reciprocating Compressor is governed by the speed of the compressor. If the speed of the compressor is larger than 0 then the flow rate is 0 or larger then 0 (but never negative). The molar flow is then equal to:  1    N * PD * ρ  L  Zs Pd k       F = 1 − −C − 1 60 100  Zd  Ps  MW           where: N = speed, rpm ρ = gas density MW = gas molecular weight If the speed of the compressor is exactly zero, then the flow through the unit is governed by a typical pressure flow relationship and you can specify the resistance in zero speed flow resistance, . k zero_speed The flow equation is: Mola Flow,F = k ze o speed * ρ * ∆P f iction 618 v Compressor or Expander where: ΔP friction = frictional pressure drop across the compressor v 619 Chapter 8: General Unit Operations Valve Petro-SIM performs a material and energy balance on the inlet and exit streams of the Valve operation. It is assumed the Valve operation is enthalpic and therefore Petro-SIM performs a flash calculation based on equal material and enthalpy between the two streams. Variables that can be specified by the user in the Valve operation are: l l l l l Inlet temperature Inlet pressure Outlet temperature Outlet pressure Valve Pressure Drop Three specifications are required before the Valve operation solves. At least one temperature specification and one pressure specification are required. Petro-SIM calculates the other two unknowns. 1. To add a Valve to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Isenthalpic Valve (or click and drag it to the flowsheet). A Valve is added to the active flowsheet. 620 v Valve Valve Operation in the PFD 3. In the Valve view, enter the Valve properties in these tabs: l Design l Rating l Worksheet l Dynamics - This tab is available only when working in Dynamics mode. 4. To ignore the Valve operation during calculations, check Ignored. Design Modify the Valve Design tab settings on these pages: Connections The Connections page lets you specify the name of the operation, as well as the inlet stream and outlet stream. Parameters Specify the pressure drop of the Valve operation on the Parameters page. v 621 Chapter 8: General Unit Operations You can also add User Variables and Notes. Rating The Valve Rating tab contains these pages: Sizing Specify the valve's manufacturer, characteristics, and sizing details on this page. 622 v Valve Flow Limits v 623 Chapter 8: General Unit Operations Relief Valve The Relief Valve unit operation can be used to model several types of spring loaded Relief Valves. Relief Valves are frequently used in many different industries to prevent dangerous pressure buildups in a system. The flow through the Relief Valve can be vapour, liquid, liquid with precipitate, or any combination of the three. For more information, refer to Relief Valve theory. 1. To add a Relief Valve to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Relief Valve (or click and drag it to the flowsheet). A Relief Valve is added to the active flowsheet. 3. In the Relief Valve property view, enter the properties in these tabs: l Design l Rating l Worksheet l Dynamics - This tab is available only when working in Dynamics mode. 4. To ignore the Relief Valve during calculations, check Ignored. Design Modify the Relief Valve Design tab settings on these pages: Connections Use the Connections page to specify the inlet and outlet streams attached to the Relief Valve. 624 v Relief Valve The page contains three fields: Field Description Name The name of the Relief Valve. Petro-SIM provides a default designation for the unit operation, you can edit this name at any time by entering a new name in this field. Inlet Stream entering Relief Valve. You can either select a pre-existing stream from the drop-down list associated with this field or you can create a new stream by selecting this field and typing the stream name. Outlet Relief Valve exit stream. Like the Inlet field, you can either select a preexisting stream from the drop-down list associated with this field or you can create a new stream by selecting this field and typing the stream name. Parameters Use the Parameters page to modify these parameters: v 625 Chapter 8: General Unit Operations Parameter Description Set Pressure The pressure that the Relief Valve begins to open. Full Open Pressure The pressure that the Relief Valve is fully open. You can also add User Variables and Notes. Rating The Relief Valve Rating tab contains these pages: Sizing On the Sizing page, you can specify the Valve Type, the Capacity Correction Factors and Parameters. 626 v Relief Valve You can specify three different valve characteristics for any Relief Valve in the simulation case. Valve Type Description Quick Opening A Relief Valve with quick opening valve characteristics obtains larger flows initially at lower valve openings. As the valve opens further, the flow increases at a smaller rate. Li near A Relief Valve with linear valve characteristics has a flow, which is directly proportional to the valve % opening. Equal Percentage A Relief Valve with equal percentage valve characteristics initially obtains very small flows at lower valve openings. The flow increases rapidly as the valve opens to its full position. You can set: l l l l l Viscosity Coefficient (K ) V Discharge Coefficient (K ) D Back Pressure Coefficient (K ) B Valve Head Differential Coefficient Orifice Area (A) Relief Valve Theory The mass flow rate through the Relief Valve varies depending on the vapour fraction and the pressure ratio across the valve. For 2-phase flow, the flows are proportional to the vapour fraction and can be calculated separately and then combined for the total flow. For gases and vapours, flow may be choked or non-choked. If the pressure ratio is greater than the critical, the flow is not choked: K P2 2  K −1  ≥ P1  K + 1  where: P = upstream pressure 1 P = downstream pressure 2 K = ratio of Specific Heats For Choked vapour flow, the mass flowrate is given by the relationship: v 627 Chapter 8: General Unit Operations 1 K +1  2  P 1K  2  K −1   W = AKLKDKB  V1  K + 1     where: W = mass flow rate A = relief valve orifice area K = capacity correction factor for valve lift L K = coefficient of discharge D K = back pressure coefficient B V = specific volume of the upstream fluid 1 For non-Choked vapour flow, the mass flowrate is given by: 1 K +1  2   2  P K P K P 2   2  −  2  K  W = AKLKD 1  V K − 1  P 1    P1    1     Liquid Flow through the valve is calculated using the equation: 1 W = AKLKDKV 2(P 1 − P 2)ρ 1 2 where: ρ = density of upstream fluid 1 K = viscosity correction factor V The Capacity Correction Factor for back pressure is typically linear with increasing back pressure. The correct value of the factor should be user specified. It may be obtained from the valve manufacturer. The capacity correction factor for valve lift compensates for the conditions when the Relief Valve is not completely open. Increasing-sensitivity valves have the flow characteristics: KL = L 1 a + (1 − a )L4  2   Linear and decreasing-sensitivity valves have the flow characteristics: 628 v Relief Valve L2 KL = 1 a + (1 − a )L2 2   where: a= valve head differential at maximum flow valve head differential at zero flow The valve head differential term allows for customization of the flow characteristics with respect to stem travel. Its value can range between 0 and 1. v 629 Chapter 8: General Unit Operations Pipe Segment The Pipe Segment unit operation is used to simulate a wide variety of piping situations ranging from single or multiphase plant piping with rigorous heat transfer estimation, to large capacity looped pipeline problems. Refer to Calculation Modes and Incremental Material and Energy Balances for more information about the calculating pipe segments. 1. To add a Pipe Segment to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Pipe Segment (or click and drag it to the flowsheet). A Pipe Segment is added to the active flowsheet. 3. In the Pipe Segment property view, enter the properties in these tabs: l Design l Rating l Worksheet l Performance l Deposition l Dynamics - This tab is available only when working in Dynamics mode. 630 v Pipe Segment 4. To ignore the Pipe Segment during calculations, select the Ignored check box. PetroSIM disregards the operation until you deactivate the check box. You can delete the operation by clicking the Delete button. Petro-SIM will ask you to confirm the deletion. Design Modify the Pipe Segment Design tab settings on these pages: Connections On the Connections page, specify the feed and product material streams. In the Inlet, Outlet and Energy drop-down lists either type in the name of the stream or select it from the drop-down list. In addition to the material stream connections, you also have the option of attaching an energy stream to the Pipe Segment and selecting the fluid package for the Pipe Segment. Optionally, modify the name of the pipe segment. Parameters Use the Parameters page to modify these Pipe Segment parameters: v 631 Chapter 8: General Unit Operations Pipe Flow Correlation Methods These methods have all been developed for predicting two-phase pressure drops. Some methods were developed exclusively for flow in horizontal pipes, others exclusively for flow in vertical pipes while some can be used for either. Some of the methods define a flow regime map and can apply specific pressure drop correlations according to the type of flow predicted. Some of the methods calculate the expected liquid holdup in two-phase flow while others assume a homogeneous mixture. The table summarizes the characteristics of each model. 632 v Model Horizontal Flow Vertical Flow Liquid Holdup Flow Map Aziz, Govier & Fogarasi No Yes Yes Yes Baxendell & Thomas Use with Care Yes No No Beggs & Brill Yes Yes Yes Yes Duns & Ros No Yes Yes Yes Gregory, Aziz, Mandhane Yes Use with Care Yes Yes Pipe Segment Model Horizontal Flow Vertical Flow Liquid Holdup Flow Map Hagedorn & Brown No Yes Yes No Orkisewski No Yes Yes Yes Poettman & Carpenter No Yes No No Tulsa No Yes Yes Yes For Single Phase streams, the Darcy equation is used for pressure drop predictions. This equation is a modified form of the mechanical energy equation, which takes into account losses due to frictional effects as well as changes in potential energy. The total heat loss from the Pipe Segment is indicated in the Duty field. The total heat loss can be calculated using estimated heat transfer coefficients or specified on the Heat Transfer page of the Rating tab. You can also specify the overall pressure drop for the operation. The pressure drop includes the losses due to friction, static head and fittings. If the overall pressure drop is not specified on the Parameters page, it is calculated by Petro-SIM, provided all other required parameters are specified. The Gravitational Energy Change field displays the change in potential energy experienced by the fluid across the length of the pipe. It is determined for the overall elevation change, based on the sum of the elevation change specified for each segment on the Sizing page of the Rating tab. When the pressure drop is specified, the Pipe Segment can be used to calculate either the length of the Pipe Segment or the flow of the material through the length of pipe. Notice the calculation type (i.e., pressure drop, length, flow) is not explicitly specified. Petro-SIM determines what's to be calculated by the information you provide. Calculation Specify the pipe calculation parameters on this page. Refer also to Calculation Modes. v 633 Chapter 8: General Unit Operations 634 v Field Description Pressure Tolerance Tolerance used to compare pressures in the calculation loop. Temperature Tolerance Tolerance used to compare temperatures in the calculation loop. Heat Flow Tolerance Tolerance used to compare heat flow in the calculation loop. Length Initial Guess Used in the algorithm when length is to be calculated. Length Step Size Used in the algorithm when length is to be calculated. Flow Initial Guess Used in the algorithm when flow of material is to be calculated. Flow Step Size Used in the algorithm when flow of material is to be calculated Diameter Initial Guess Optional estimate when diameter is to be calculated. Default Increments The increment number which appears for each segment on the Dimensions page Always PH Flash Activate this check box to force Petro-SIM calculations to be done using PH flashes rather than PT flashes. Slower but more reliable for pure component or narrow boiling range systems. Check Choked Flow When this check box is active, Petro-SIM checks for choked flow. The default setting is inactive because the command slows down calculations. Pipe Segment Field Description This check is carried out only on pipe segments not on fitting or swage segments. Do Deposition Calcs When this check box is inactive, Petro-SIM turns off deposition calculations. This check box is a duplicate of the check box on the Deposition tab Do Slug Tool Calculations When this check box is active, Petro-SIM performs slug calculations. When calculating Flow or Length, good initial guesses and step sizes can reduce solution time. You can also add User Variables and Notes. Aziz, Govier & Fogarasi In developing their model1 Aziz, Govier & Fogarasi argue that flow regime is independent of phase viscosities and pipe diameters but is proportional to the gas density to the one-third power ρ 1/3 ( g ). When two liquid phases are present, appropriate volume based empirical mixing rules are used to calculate a single pseudo liquid phase. Use caution in interpreting the calculated pressure drops for three-phase systems. Actual pressure drops can vary dramatically for different flow regimes and for emulsion systems. From this, they then calculate modified superficial gas and liquid velocities on which they base the flow regime map. v 635 Chapter 8: General Unit Operations Once the flow regime has been determined a range of correlations is used to determine the frictional pressure gradient and slip velocity or void fraction applicable to that regime. Baxendell & Thomas The Baxendell & Thomas model2 is an extension of the Poettman & Carpenter model to include higher flow rates. It is based on a homogeneous model using a 2-phase friction factor obtained from correlation based on experimental results relating friction factor to the parameter Dρυ. Baxendell & Thomas fitted a smooth curve for values of the Dρυ parameter greater than 45 x103 cp. Below this value they propose that original correlation of Poettman & Carpenter be used. Baxendell & Thomas claim the correlation is suitable for use in calculating horizontal flow pressure gradients in addition to the vertical flow pressure gradients for which the original Poettman & Carpenter approach was developed although the correlation takes no account of the very different flow regimes that can occur. Like the Poettman & Carpenter model this model assumes that the pressure gradient is independent of viscosity. Beggs and Brill Pressure Gradient The Beggs and Brill3 method is based on work done with an air-water mixture at many different conditions and is applicable for inclined flow. 636 v Pipe Segment In the Beggs and Brill correlation, the flow regime is determined using the Froude number and inlet liquid content. The flow map used is based on horizontal flow and has four regimes: segregated, intermittent, distributed and transition. Once the flow regime has been determined, the liquid holdup for a horizontal pipe is calculated, using the correlation applicable to that regime. A factor is applied to this holdup to account for pipe inclination. From the holdup, a 2phase friction factor is calculated and the pressure gradient determined. Duns and Ros The Duns and Ros model6 is based on a large scale laboratory investigation of upward vertical flow of air/hydrocarbon liquid and air / water systems. The model identifies 3 flow regions. l l l Region I. Where the liquid phase is continuous (i.e., bubble and plug flow and part of froth flow regimes). Region II. Where the phases of liquid and gas alternate (i.e., remainder of froth flow regime and slug flow regime). Region III. Where gas phase is continuous (i.e., mist flow and annular flow regime). The flow region map is shown in the figure: v 637 Chapter 8: General Unit Operations The regions are distinguished using functions of four dimensionless groups: a gas velocity number, a liquid velocity number, a diameter number and a liquid viscosity number. Separate frictional pressure drop correlations and liquid slip velocity (liquid holdup) correlations are defined for each region in terms of the same dimensionless groups. Gregory Aziz Mandhane Pressure Gradient For the Gregory Aziz Mandhane correlation7 , an appropriate model is used for predicting the overall pressure drop in 2-phase flow depending upon the flow regime as shown. 638 v Pipe Segment Regime Model Slug flow Mandhane, et. al. modification #1 of Lockhart-Martinelli Dispersed Bubble Mandhane, et. al. modification #2 of Lockhart-Martinelli Annular Mist Lockhart-Martinelli Elongated Bubble Mandhane, et. al. modification #1 of Lockhart-Martinelli Stratified Lockhart-Martinelli Wave Lockhart-Martinelli Hagedorn & Brown Hagedorn & Brown based their model8 on experimental data on upward flow of air / water and air / oil mixtures. The frictional pressure drop is calculated using a friction factor derived from a single phase Moody curve using a two phase Reynolds number that reduces to the appropriate single phase Reynolds number when the flow becomes single phase. For the void fraction required to calculate the two phase Reynolds number and the static pressure loss, Hagedorn & Brown developed a single curve relating the void fraction to the same dimensionless parameters proposed by Duns & Ros. v 639 Chapter 8: General Unit Operations Orkisewski Orkisewski12 composed a composite correlation for vertical upward flow based on a combination of methods developed by Griffith (1962), Griffith & Wallis(1961) and Duns & Ros (1963)6 . Four flow regimes are defined and the methods proposed for each region are: l l l l Bubble flow - Griffith correlation Slug/Plug flow - Griffith & Wallis correlation modified by Orkisewski Churn flow - Duns & Ros Mist/Annular flow - Duns & Ros Orkisewski proposed that the method of Griffith and Wallis be used to determine the boundary between the bubble and plug flow regime and the methods of Duns & Ros be used to determine the remaining flow regime boundaries. Poettman & Carpenter The Poettman & Carpenter model13 assumes that the contribution of the acceleration term to the total pressure loss is small and that the frictional pressure drop can be calculated using a homogeneous model. The model further assumes that the static head loss can be calculated using a homogeneous two phase density. Poettman & Carpenter varies from a standard homogeneous method in its calculation of a two phase friction factor. The model proposes a correlation for the friction factor based on experimental results from 49 flowing and gas lift wells operating over a wide range of conditions. The 2-phase friction factor is plotted against the parameter Dρυ (D= diameter, ρ = homogeneous density and = υ homogeneous superficial velocity). The model assumes the pressure gradient is independent of viscosity. Tulsa The Tulsa model15 proposes a comprehensive mechanistic model formulated to predict flow patterns, pressure drop and liquid holdup in vertical upward two-phase flow. The model identifies five flow patterns: bubble, dispersed bubble, slug, churn and annular. The flow pattern prediction models used are Ansari et. al. (1994) for dispersed bubble and annular flows, Chokshi (1994) for bubbly flow and a new model for churn flow. The resulting flow pattern map is shown. 640 v Pipe Segment Separate hydrodynamic models for each flow pattern are used. A new hydrodynamic model is proposed for churn flow and a modified version of Chokshi’s model is proposed for slug flow. Chokshi and Ansari et. al. models are adopted for bubbly and annular flows respectively. The model has been evaluated using the Tulsa University Fluid Flow Projects well data back of 2052 wells covering a wide range of field data. The model has been compared with Ansari et. al. (1994), Chokshi (1994), Hasan & Kabir (1994), Aziz et. al. (1972) and Hagedorn and Brown (1964) methods and is claimed to offer superior results. All methods account for static head losses, while only the Beggs and Brill method accounts for hydrostatic recovery. Beggs and Brill calculate the hydrostatic recovery as a function of the flow parameters and pipe angle. Rating The Pipe Segment Rating tab consists of these pages: l l Sizing Heat Transfer Sizing On the Sizing page on the Rating tab, the length-elevation profile for the Pipe Segment is constructed. You can provide details for each fitting or pipe section that is contained in the Pipe Segment that you're modelling. An unlimited number of pipe sections or fittings can be added on this page. v 641 Chapter 8: General Unit Operations For a given length of pipe that is modelled in Petro-SIM, the parameters of each segment are entered separately, as they're for each fitting. The procedure for modelling a length of pipe is illustrated. In the diagram, the pipe length AD is represented by segments A, B, C, D and three fittings. The table shown displays the fitting/pipe, length and elevation input that you require to represent the pipe length AD. The horizontal pipe sections have an Elevation of 0. A positive elevation indicates that the outlet is higher than the inlet. Each pipe section and fitting is labelled as a segment. 642 v Pipe Segment 1 Number 2 3 4 5 6 7 Represented by A F1 B F2 C F3 D Fitting/Pipe Pipe Fitting Pipe Fitting Pipe Fitting Pipe Length x N/A y N/A x N/A Elevation 0 N/A y N/A 0 N/A 1 1 1 2 x32 + y 22 y 2 To fully define the pipe section segments, you must also specify pipe schedule, diameters (nominal or inner and outer), a material and a number of increments. The fittings require an inner diameter value. When you have only one pipe segment Petro-SIM calculates the inner diameter of the pipe when a pressure difference and pipe length is specified. To Append Segments 1. To add segments to the length-elevation profile, click Append Segment. v 643 Chapter 8: General Unit Operations 2. Click Delete Segment to delete an existing Length - Elevation Profile. 3. For each segment that you add, specify the following: Field Description Pipe/Fitting/Swage Select a pipe section, swage or one of the available fittings from the drop-down list. If the list does not contain the fitting required, you can modify the fittings and change its K-factor for these calculations. The pipe segment report has been updated to include dedicated detail sections for both fittings and swage fittings. These sections appear in the parameters data block. You can modify the Fittings Database, which is contained in file FITTING.DB. Length The actual length of the Pipe Segment. Not required for fittings. Elevation Change The change in vertical distance between the outlet and inlet of the pipe section. Positive values indicate that the outlet is higher than the inlet. Not required for fittings. Outer Diameter Outside diameter of the pipe or fitting. Inner Diameter Inside diameter of the pipe or fitting. Material Select one of the available default materials or choose User Specified for the pipe section. Not required for fittings. Increments The number of increments the pipe section is divided for calculation purposes. Once you have selected the segment type (pipe, fitting, or swage), you can specify detailed information for the segment. Select a segment, and then click View Segment. Depending on the type of Fitting/Pipe you selected , the Pipe Fittings, Pipe Swages, or Pipe Info view appears. Pipe Fittings view You can customize the pipe in the Pipe Fittings view. 644 v Pipe Segment The above view shows a standard fitting as it would be retrieved from the fittings database. If you customize a fitting by changing either the VH Factor or FT Factor, the word User is added to the fitting name to denote the fact that it is now user defined and the Data Source field becomes updateable to let you describe the source of the new data. Fitting Pressure Loss The fittings pressure loss is characterized by a two constant equations. K = A + B * fT where: A = constant, also known as velocity head factor B = constant, also known as FT factor f = fully turbulent friction factor T The fittings pressure loss constant K is then used to obtain the pressure drop across the fitting from the equation. ∆P = K ρv 2 2 where: ΔP = pressure drop ρ = density υ = velocity Calculation of the fully turbulent friction factor fT needed in the method requires knowledge of the relative roughness of the fitting. This is calculated from user entered values for roughness and fitting diameter. v 645 Chapter 8: General Unit Operations The Pipe Segment’s standard friction factor equation (Churchill) is then called repeatedly with the calculated relative roughness at increasing Reynolds numbers until the limiting value of friction factor is found. In general a fitting is characterized by either a velocity head factor (A) or a FT factor (B) but not both. Petro-SIM does not enforce this restriction and you are free to define both factors for a fitting if required. Pipe Swages view A Pipe Swages view lets you update the swage angle for a swage fitting. It also displays the upstream and downstream diameters that are used in the calculation. The automatic detection of upstream and downstream diameters by the swage segment means that there cannot be two consecutive swage segments in a pipe. This restriction is enforced by Petro-SIM, which prevents you from specifying two adjacent segments to be swages. In addition, if two adjacent swage segments would result from deletion of an intervening pipe or fitting segment, the second swage segment is automatically converted to a default Pipe Segment. An explanatory message appears in both cases. Swage Fittings This feature allows the pressure drop across reductions or enlargements in the pipe line to be calculated. The feature has been added as a fitting type called a swage. The swage fitting automatically uses the upstream and downstream pipe/fitting diameters to calculate the K factor for the fitting. Once the K factor is known the pressure loss across the reducer/ enlarger can be calculated. The equations used are as follows. ∆P = K out where: 646 v 2 ρoutv out 2 − ρ in v in2 2 + 2 ρoutv out 2 Pipe Segment ΔP = static pressure loss ρ = density v = velocity K = reducer/enlarger K factor The K factor from the above equation is calculated from one of the following equations: For reducers θ 2 K out = 0.8sin 1 − β  for (θ ≤ 45 ° 2     θ 2 K out = 0.51 − β  sin for (45 ° < θ ≤ 180 ° 2    where: β= d out d in For enlargers K out = 2.6sin 2 θ 1−β2 2 4 ( β ) for (θ ≤ 45 °) 2 K out = (1 − β 2) β4 for (45 ° < θ ≤ 180 °) where: β= d out d in θ in the equations above is known as swage angle. Equations for K above are taken from Crane, Flow of Fluids, Publication 410M, Appendix A-26. v 647 Chapter 8: General Unit Operations A swage segment automatically considers the upstream (d ) and downstream (d ) diameters to in out work out whether the swage is a reducer or an enlarger and calculate the appropriate K value. In addition the special cases are detected and a fixed K value is used. l l l The swage is the first segment in the pipe and an entrance K value of 0.5 is used. The swage is the last segment in the pipe and an exit K value of 1.0 is used. d =d the swage is a simple coupling and a K value of 0.04 is used. in out Pipe Info view The Pipe Info view appears for pipe sections. Field Description Pipe Schedule Select one of: l l l l Actual. The nominal diameter cannot be specified. The inner diameter can be specified. Schedule 40 Schedule 80 Schedule 160 Petro-SIM contains a pipe database for three pipe schedules (40, 80, 160). If a schedule is specified, a popup menu appears indicating the possible nominal pipe diameters that can be specified. 648 v Nominal Diameter Provides the nominal diameter for the pipe section. Inner Diameter For Schedule 40, 80, or 160, this is referenced from the database. For Actual Pipe Schedule, this can be specified directly by you. Pipe Segment Field Description Pipe Material Select a pipe material or choose User Specified. The pipe material type can be selected from the drop-down list in the field. A table of pipe materials and corresponding Absolute Roughness factors is shown in the table below. The roughness factor is automatically specified for pipe material chosen from this list. You can also specify the roughness factor manually. Roughness A default value is provided based on the Pipe Material. You can specify a value if you want. Pipe Wall Conductivity Thermal conductivity of pipe material in W/m.K to allow calculation of heat transfer resistance of pipe wall. Defaults provided for standard pipe materials are as follows: l l l l l l All steel and coated iron pipes: 45.0 Cast iron: 48.0 Concrete: 1.38 Wood: 0.173 PlasticTubing: 0.17 RubberHose: 0.151 Pipe Material Type and Absolute Roughness factors Pipe Material Type Absolute Roughness, m Drawn Tube 0.0000015 Mild Steel 0.0000457 Asphalted Iron 0.0001220 Galvanized Iron 0.0001520 Cast Iron 0.0002590 Smooth Concrete 0.0003050 Rough Concrete 0.0030500 Smooth Steel 0.0009140 Rough Steel 0.0091400 v 649 Chapter 8: General Unit Operations Pipe Material Type Absolute Roughness, m Smooth Wood Stave 0.0001830 Rough Wood Stave 0.0009140 Heat Transfer The Heat Transfer page on the Rating tab is used to enter data for defining the heat transfer. The Specify By group, at the top of the view, contains four ways to define heat transfer: l l l l Specified heat loss Overall Heat Transfer Coefficient (HTC) HTC specified by segment Estimated HTC The radio button does not force the pipe segment to use that method of calculation; it only provides access to the views. Petro-SIM works out which method to use from the data provided. Heat Loss Petro-SIM selects the Heat Loss option as the default setting, when you select the Heat Transfer page for the first time. 650 v Pipe Segment If the Overall heat duty of the pipe is known, the energy balance can be calculated immediately. Each increment is assumed to have the same heat loss. You enter the heat loss for the pipe in the Heat Loss field. This assumption is valid when the temperature profile is flat, indicating low heat transfer rates compared to the heat flows of the streams. This is the fastest solution method. If both inlet and outlet temperatures are specified, a linear profile is assumed and Petro-SIM can calculate the overall heat duty. The value in the Heat Loss field is black in colour, signifying that the value was generated by Petro-SIM. This method allows fast calculation when stream conditions are known. Select the Heat Loss radio button to see the calculated overall heat duty. Overall HTC When you select the Overall HTC option, the Heat Transfer page changes. v 651 Chapter 8: General Unit Operations If the overall HTC (Heat Transfer Coefficient) and a representative ambient temperature are known, rigorous heat transfer calculations are performed on each increment. Segment HTC When you select the Segment HTC radio button, the Heat Transfer page changes. 652 v Pipe Segment If the heat transfer coefficient and a representative ambient temperature are known for each segment. You can specify the ambient temperature and HTC for each pipe segment that was created on the Sizing page. Petro-SIM performs rigorous heat transfer calculations on each increment. Estimate HTC When you select the Estimate HTC radio button, the Heat Transfer page changes. v 653 Chapter 8: General Unit Operations From the Ambient T Method, select: l l By Segment - ambient temperature applies to each segment of pipe Global - ambient temperature applies to entire pipe If the pipe’s HTC is unknown, you can enter information in this view and Petro-SIM calculates the HTC for the pipe. Inside Film Convection You can prompt Petro-SIM to estimate the inside film heat transfer coefficient using one of the five correlations provided. The Petukov, Dittus and Sieder methods for calculation of inner HTC are limited to single phase applications and essentially turbulent flow only. Two and three phase systems are modelled using the single phase equations with “averaged” fluid properties. A correction for laminar flow is applied but this is not particularly effective. It is recommended these three methods be used only for single phase pipelines operating at high Reynolds numbers (> 10000). The Profes and HTFS methods should provide much better results for two and three phase systems and in the laminar flow region at the cost of some increase in calculation time. Generally the Profes option is recommended for most pipeline applications since it takes into full account the flow regime in the pipe and is reasonably efficient in calculation. The HTFS option is more calculation 654 v Pipe Segment intensive, particularly in two phase applications where additional flash calculations are required. It is recommended for use in cases with a high heat flux with high delta temperatures between the pipe contents and ambient conditions. The 5 correlations provided are: l Petukov (1970) h= l (f / 8)Re d Pr k d 1.07 = 12.7(F / 8)1/ 2 Pr 2/ 3 − 1 ( ) Dittus and Boelter (1930) k d where: h = 0.023Re d0.8Pr n n= l 0.4 ⇒ for heating 0.3 ⇒ for cooling Sieder and Tate (1936) k d h = 0.027Re d0.8Pr 1/3 l l Profes - Implements the methods used by the Profes Pipe Simulation program (formerly PLAC). The methods are based on the Profes flow maps for horizontal and vertical flow and appropriate correlations are used to determine the HTC in each region of the flow map. HTFS -Implements the methods used by HTFS programs. Separate correlations are used for boiling and condensing heat transfer and for horizontal and vertical flow. You can choose to include the pipe’s thermal resistance in your HTC calculations by activating the Include Pipe Wall check box. Activating this option requires that the thermal conductivity be defined for the pipe material on the detail view of each Pipe Segment. Default values of thermal conductivity are provided for the standard materials that can be selected in the Pipe Segment. Conduction Through Insulation Conduction through the insulation or any other pipe coating can also be specified. Several representative materials are provided, with their respective thermal conductivities. Specify a thickness for this coating. v 655 Chapter 8: General Unit Operations Insulation / Pipe Conductivity Insulation / Pipe Conductivity Evacuated Annulus 0.005 W/mK Asphalt 0.700 W/mK Urethane Foam 0.018 W/mK Concrete 1.000 W/mK Glass Block 0.080 W/mK Concrete Insulated 0.500 W/mK Fiberglass Block 0.035 W/mK Neoprene 0.250 W/mK Fiber Blanket 0.070 W/mK PVC Foam 0.040 W/mK Fiber Blanket-Vap Barr 0.030 W/mK PVC Block 0.150 W/mK Plastic Block 0.036 W/mK Polystyrene Foam 0.027 W/mK Outside Conduction/Convection Outside convection to either air, water or ground can be included by activating the Include Outer HTC check box. For air and water, the velocity of the ambient medium is defaulted to 1 m/s and is user modifiable. The outside convection heat transfer coefficient correlation is for flow past horizontal tubes (J.P. Holman, 1989): k d If Ground is selected as the ambient medium, the Ground type can then be selected. The thermal conductivity of this medium appears but is also modifiable by typing over the default value. h = 0.25Re 0.6Pr 0.38 The Ground types and their corresponding conductivities are: Ground Type Conductivity Ground Type Conductivity Dry Peat 0.17 W/mK Frozen Clay 2.50 W/mK Wet Peat 0.54 W/mK Gravel 1.10 W/mK Icy Peat 1.89 W/mK Sandy Gravel 2.50 W/mK Dry Sand 0.50 W/mK Limestone 1.30 W/mK Moist Sand 0.95 W/mK Sandy Stone 1.95 W/mK Wet Sand 2.20 W/mK Ice 2.20 W/mK Dry Clay 0.48 W/mK Cold Ice 2.66 W/mK Moist Clay 0.75 W/mK Loose Snow 0.15 W/mK Wet Clay 1.40 W/mK Hard Snow 0.80 W/mK The heat transfer resistance is estimated from: 656 v Pipe Segment R surroundings = 2 2 Dot  2Zb + 4Z b − Dot  ln  2k s Dot   where: Z = depth of cover to centre line of pipe b k = thermal conductivity of pipe-surrounding material (Air, Water, Ground) s D ot = outer diameter of pipe, including insulation Performance The Pipe Segment Performance tab contains pages that display the results of the Pipe Segment calculations: Profiles The Profiles page lets you access information about the fluid stream conditions for each specified increment in the Pipe Segment. The page contains a summary table for the segments that make up the Pipe Segment. The distance (length), elevation and number of increments appear for each segment. You cannot modify the values on this page. v 657 Chapter 8: General Unit Operations By clicking the View Profile button, the Pipe Profile view appears, which consists of a Table tab and a Plot tab. The Table tab displays the information for each increment along the Pipe Segment: l l l l l l l l l l l l l l l l Length Elevation Pressure Temperature Heat Transferred Flow Regime Liquid Holdup Friction Gradient Static Gradient Accel Gradient Liquid Reynolds Number Vapour Reynolds Number Liquid Velocity Vapour Velocity Deposit Thickness Deposit Volume The Plot tab graphically displays the profile data listed on the Table page. Select one of the radio buttons to view a profile with Length as the x-axis variable: 658 v Pipe Segment Slug Options The entries on the Slug Options page control the models and parameters used by the slug tool in its calculations as follows: Translational Model You can select the option to be used for calculating the translational velocity of the slugs in the pipeline. The general form of the translational velocity is of the form: c = C 0VM + U 0 where: c = translation velocity of slug V = superficial velocity of two phase mixture M C , U = constants 0 0 You can select the Bendikson (1984) model to predict values of C and U or to select User 0 0 Specified to enter values manually. Holdup Model You can select the option to be used to calculate the liquid holdup in the pipe. Two options are available: Gregory et. al. uses the methods published by Gregory et. al. (1978) or User Specified to enter a user defined value for the holdup fraction. Friction Factor Two options are available to select the friction factor model to be used in the slug tool calculations: Smooth pipe or Colebrook equation. Frequency Option v 659 Chapter 8: General Unit Operations The slug tool evaluates slug flow characteristics at a particular slug frequency. This frequency can either be predicted by the Hill & Wood correlation or specified by the user. About the Slug Tool The Slug Tool predicts slug properties for horizontal and inclined two-phase flows in each Pipe Segment. Travelling wave solutions of the one-dimensional averaged mass and momentum equations are found and analyzed to obtain slug flow properties. Stratified flow is tested for instability to small disturbances and then analyzed in the unstable region to find if slug flow is possible. If large amplitude waves can bridge the pipe then slug flow is deemed to be possible. In this slug flow region a range of frequencies is possible with a maximum slug frequency occurring for slugs of zero length. Up to this maximum there is a relationship between frequency and slug length with maximum lengths occurring for the lowest frequencies. The other slug properties such as bubble length, average film holdup, slug transitional velocity, average pressure gradient can all be found over the range of allowable slug frequencies. The detailed methodology used to predict slug formation and slug properties is described in the paper The modelling of slug flow properties1 . Slug Results The Slug Results page presents the result from the slug tool analysis as a table with these 1Watson, M., The modelling of slug flow properties, 10th International Conference Multiphase '01, Cannes, France, 13- 15 June 2001. 660 v Pipe Segment entries. Column Description Position Distance along the pipe. Status Result of the slug calculations. Possible results are Single Phase, Stable two phase, Slug flow, Annular flow, Bubble flow or Unknown. Any error in the calculation is also reported here. Frequency Slug frequency used to calculate the slug properties. This is normally the value calculated by the Hill & Wood correlation or the user specified slug frequency according to the settings on the Slug Options page. When the correlation or user specified frequency lies outside the predicted range of slug frequencies this field shows either the minimum or maximum slug frequency that is indicated by the entry in the next column. Slug Length Average length of a slug at the indicated frequency. Bubble Length Average length of a bubble at the indicated frequency. Film Holdup Film holdup as a fraction. Velocity Translational velocity of the slug. Pressure Gradient Pressure drop over the slug/bubble unit. Slug/Bubble ratio Ratio of lengths of slug and bubble. v 661 Chapter 8: General Unit Operations Cell Details When you click the View Cell Plot button on the Slug Results page, the Cell Details view appears. The view shows the slug properties for a single position in the pipe across the full range of possible slug frequencies in both tabular and graphical form. A further graph shows the flow regime map for the cell indicating the region of possible slug formation at different vapour and liquid flow rates. The Next button and Previous button on the view let you move along the pipe to inspect the detailed results at any point. Deposition Deposition is a general capability that can be used to model deposition of material that affects pressure drop or heat transfer to or from the pipe. Possible deposits include wax, asphaltenes, hydrates, sand, etc. The Deposition tab consists of these pages: Methods The Methods page displays the available deposition methods. Petro-SIM provides a model for one type of deposit, namely Wax deposition modelled using the Profes Wax model. Other third party methods can be added as plug-in extensions. 662 v Pipe Segment When solving with its default data, the model displays a warning message in the status bar of the Pipe Segment. 1. From the Deposition Correlation list, select Profes. 2. In the Profes Wax View, modify the parameters on these tabs: l Wax Data l Tuning Data l Ref Comp On installation, the Pipe Segment is not able to solve until the initial deposition thickness is defined on the Profiles page. Once the initial deposition thickness is defined, the model solves using the default values provided for the other deposition data properties. The Max. Time field lets you specify the maximum amount of time wax deposits on the pipe. The Timestep field lets you specify the timestep that the deposition rate is integrated over. Properties The Properties page lets you specify deposit properties required by the deposition calculations. The page consists of three properties: v 663 Chapter 8: General Unit Operations l l l Density of the deposit. Thermal Conductivity of the deposit Yield Strength of the deposit. Profile The Profile page consists of the Deposition Profile table. This table has 2 purposes: l l Used to specify the initial deposition thickness, required by the deposition calculations. Displays the profile of the deposit on the pipe. Limits The Limits page lets you specify the maximum limits for: l l l l l 664 v Max. Deposit Thickness Overall Pressure Drop Total Deposit Volume Plug Pressure Drop Simulation Time Pipe Segment Calculation Modes There are four calculation modes: Pressure Drop Assuming that a feed, product and energy stream are attached to the pipe, this information is required: l l l l Flow Pipe length, diameter and elevation change Heat transfer information At least one stream temperature and one pressure There are two different methods for calculating the pressure drop. Method 1 If you specify the temperature and pressure at the same end of the pipe, then energy and mass balances are solved for each increment and the temperature and pressure of the stream at the opposite end of the pipe are determined. v 665 Chapter 8: General Unit Operations 1. At the end where temperature and pressure are specified, solve for the outlet temperature and pressure in the first segment. 2. Move to the next segment, using the outlet conditions of the previous segment as the new inlet conditions. 3. Continue down the pipe until the outlet pressure and temperature are solved. Method 2 If you specify temperature for one stream and pressure for the other, an iterative loop is required outside of the normal calculation procedure: 1. First, a pressure is estimated for the stream that has the temperature specified. 2. Second, the pressure and temperature for the stream at the opposite end of the pipe are determined from incremental energy and mass balances as in the first method. 3. If the calculated pressure and user-specified pressure are not the same (within a certain tolerance), a new pressure is estimated and the incremental energy and mass balances are re-solved. This continues until the absolute difference of the calculated and user specified pressures are less than a certain tolerance. a. Estimate a pressure for the stream that has a specified temperature. b. At the end where the pressure is estimated, solve for the outlet temperature and pressure in the first segment. c. Move to the next segment, using the outlet conditions of the previous segment as the new inlet conditions. d. Continue down the pipe until the outlet pressure and temperature are solved. e. If the calculated outlet pressure is not equal to the actual pressure, a new estimate is made for pressure. (Return to step 1) The calculated pressure drop accounts for fittings, frictional and hydrostatic effects. Length Assuming the feed, product and energy stream are attached, this information is required: l l l l l l l 666 v Flow Heat transfer information Pipe diameter Inlet and Outlet Pressure (or one stream Pressure and Pressure Drop) One stream temperature Initial estimate of Length Pipe Segment Length Calculation: 1. Estimate a Length. At the end where temperature is specified, solve for the outlet temperature and pressure in the first segment. 2. Move to the next segment, using the outlet conditions of the previous segment as the new inlet conditions. 3. Continue down the pipe until the outlet pressure and temperature are solved. 4. If the calculated outlet pressure is not equal to the actual pressure, a new estimate is made for length. (Return to step 1) For each segment, the Length estimate, along with the known stream specifications, are used to solve for the unknown stream temperature and pressure. If the calculated pressure is not equal to the actual pressure (within the user-specified tolerance), a new estimate is made for the length and calculations continue. A good initial guess and step size greatly decreases the solving time. The Pipe also solves for the length if you provide one pressure, two temperature specifications, and the duty. Flow Assuming that a feed, product and energy stream are attached to the pipe, this information is required: l l l l l l Pipe length and diameter Heat transfer information Inlet and Outlet Pressure (or one stream Pressure and Pressure Drop) One stream temperature Initial estimate of Flow Flow Calculation: 1. Estimate Flow. At the end where temperature is specified, solve for the outlet temperature and pressure in the first segment. 2. Move to the next segment, using the outlet conditions of the previous segment as the inlet conditions. 3. Continue down the pipe until the outlet pressure and temperature are solved. 4. If the calculated outlet pressure is not equal to the actual pressure, a new estimate is made for the flow. (Return to step 1) v 667 Chapter 8: General Unit Operations Using the flow estimate and known stream conditions (at the end with the known temperature), Petro-SIM calculates a pressure at the other end. If the calculated pressure is not equal to the actual pressure (within the user-specified tolerance), a new estimate is made for the flow and calculations continue. A good initial guess decreases the solving time significantly. Diameter Information required in this calculation mode is the same as Length, except Petro-SIM requires the length instead of the diameter of the pipe. Initial estimate of diameter can be given on the Calculation page of the Design tab. Both length and diameter calculations can only be done for pipes with a single segment. Petro-SIM checks for sonic flow if indicated by the option in the Calculation page of the Design tab. The mode is automatically assigned depending on what information is specified. Regardless of which mode you use, specify the number of increments in the pipe. Calculations are performed in each increment; for instance, in the determination of the pressure drop, energy and mass balances are performed in each increment and the outlet pressure in that increment is used as the inlet pressure to the next increment. This continues down the length of the pipe until the pipe outlet pressure is determined. The Pipe can solve in either direction. The solution procedure generally starts at the end where the temperature is known (temperature is typically not known on both ends). Petro-SIM then begins stepping through the pipe from that point, using either the specified pressure, or estimating a starting value. If the starting point is the pipe outlet, Petro-SIM steps backwards through the pipe. At the other end of the pipe, Petro-SIM compares the calculated solutions to other known information and specifications and if necessary, restarts the procedure with a new set of starting estimates. Incremental Material and Energy Balances The overall algorithm consists of three nested loops. The outer loop iterates on the increments (Pressure, Length or Flow Mode), the middle loop solves for the temperature and the inner loop solves for pressure. The middle and inner loops implement a secant method to speed convergence. The pressure and temperature are calculated as follows: 668 v Pipe Segment 1. The inlet temperature and pressure are passed to the material/energy balance routine. 2. Using internal estimates for temperature and pressure gradients, the outlet temperature and pressure are calculated. 3. Average fluid properties are calculated based on the inlet and estimated outlet conditions. 4. These properties, along with the inlet pressure, are passed to the pressure gradient algorithm. 5. With the pressure gradient, the outlet pressure can be calculated. 6. The calculated pressure and estimate pressure are compared. If their difference exceeds the tolerance (default value 0.1 kPa), a new outlet pressure is estimated and steps 3 to 6 are repeated. The tolerance is specified in the Calculation page of the Design tab. 1. Once the inner pressure loop has converged, the outlet temperature is calculated: If U and the ambient temperature are specified, then the outlet temperature is determined from: Q = U * A * ∆T LM Q = Q in − Q out where: Q = amount of heat transferred U = overall heat transfer coefficient A = outer heat transfer area ΔT LM = log mean temperature difference Q = heat flow of inlet stream in Q out l l = heat flow of outlet stream If both the inlet and outlet Pipe temperatures are known, the outlet temperature of the increment is calculated by linear interpolation. The attached duty stream then completes the energy balance. If duty is known, the outlet temperature is calculated from a PressureEnthalpy flash. 7. When the Increment outlet temperature is calculated, it is compared with the estimated outlet temperature. If their difference exceeds the tolerance (default value 0.01 o C), a new outlet temperature is estimated and new fluid properties are calculated (return to step 3). The tolerance is specified in the Calculation page of the Design tab. 8. When both the temperature and pressure converge, the outlet results are passed to the inlet of the next increment, where calculations continue. v 669 Chapter 8: General Unit Operations Profes Wax View In the Deposition tab, Methods page, when you select Profes and then click the View Method button, the Profes Wax view appears. You can change the default data in the Profes Wax model and tune it to your specific application in this view. The Profes Wax view consists of these tabs: l l l Wax Data Tuning Data Ref. Comp The Calculate Wax Formation Temperature check box allows you to select whether the deposition model is to calculate the initial wax formation temperature or cloud point for each pipe element when performing the deposition calculations. If selected, the results appear in the Profile page of the Deposition tab. The Tune button initiates the tuning calculations and is only active when there's sufficient data to allow tuning calculation to take place (i.e., cloud point is defined, at least one temperature or wax mass percent pair is defined and reference composition defined). Wax Data The Wax Data tab lets you select the wax model to be used for the wax equilibrium calculations. The Wax Model drop-down list provides you with 4 thermodynamic models for wax formation: l l l l Chung Pederson Conoco AEA (default) All models are based on the equation for the equilibrium constant, Ki, which is the ratio of concentrations of a particular component in the solid and liquid phase: where: K= xi s xi L = ζ i Lf i L  P V iL − V iS  exp ∫O RT ∂P ζ i S f iS   x = mol fraction i ζi = activity coefficient f = standard state fugacity P = pressure V = molar volume 670 v Pipe Segment T = temperature R = gas constant S, L = denote solid and liquid phases Once the equilibrium constant for each component has been calculated, they're used to determine the quantities and composition of each phase. The differences between the various thermodynamic models depend on how the terms in the equilibrium constant equation are evaluated. The 4 models available in the Profes method are described by the equations: AEA l lnKi = T  T if ∆h i f  ∆C P  1 − + 1 −  RT  R  T T if L Tf  P V − Vi + ln i  + ∫O i ∂P RT T  T  V iL ∆h i f  1 − +  RT RT  T if L 2    Chung l lnKi =   ( L δ m − δi ) + V iL VL +1− i Vm Vm Conoco (Erikson) l lnKi = T  ∆h i f  1− f   RT Ti   Pederson l 2 lnKi = V i L(δ mL − δ i L) ∆C ρ  T if ∆h i f  T  1 − + 1 −  R  T S 2 RT  T if V i S (δ mS − δ i )    Tf  + ln i  T  where: ∆ hi Ti f = enthalpy of melting f = melting temperature V = molar volume δ = solubility parameter ΔC = heat capacity difference between solid and liquid p m = denotes mixture properties v 671 Chapter 8: General Unit Operations i = component All the models require a detailed compositional analysis of the fluid in order to be used effectively and for the Conoco model Erickson et al proposed that the hydrocarbon analysis should distinguish between normal and non normal paraffin components as there's a substantial difference in melting points between these two groups. The melting temperatures make a very significant impact on the predicted cloud point for any given composition. In Pederson model the Ki values depend on the composition of the liquid and solid phases; this is unlike normal equilibrium calculations, where the Kis are fixed for any temperature and pressure and can lead to unstable or incorrect numerical solutions. The AEA model is the only model which incorporates a term for the effect of pressure on the liquidsolid equilibrium, the result of this is to counteract the increased solubility of wax forming components at high pressures which is due to more light ends entering the liquid phase. Using this model, the predicted cloud point and wax quantities can both increase or decrease with increasing pressure, depending on the fluid composition. The table lets you select which components in the system can form wax. The default criteria for the components in this table are as follows: l l Components with a mole weight less than 140 or inorganic component types can never form wax. The check box for these components is set to a grey check box that cannot be modified. Hydrocarbon component types form wax. The check box is automatically activated for these components, but you can deactivate it. Hypothetical components generally fall into this category. l Other organic component types do not form wax. The check box is inactive but you can activate it. The ability to select whether a particular component forms wax gives you additional control when defining the wax formation characteristics of a system. For example, you can define two hypothetical components with common properties and by setting one as a wax former you could vary the quantity of wax produced in the boiling range covered by the hypotheticals by varying their proportions. Tuning Data The Tuning Data tab lets you define the observed wax formation characteristics of a system to tune the wax model. 672 v Pipe Segment The Cloud Point Input field lets you specify the temperature at which the first wax appears i.e., the phase transition temperature between single liquid phase and the two phase wax/liquid mixture. The table of Temperature vs. Wax Mass Percent lets you define the quantity of wax deposit observed as a function of temperature. New points can be added to the table in any order; they're sorted by temperature when the tuning process is run. To run the tuning calculations a minimum of one pair of data points is required. Up to 10 pairs of data points can be specified. To remove a point from the table both the temperature and the wax mass percent values must be deleted. Ref Comp The Ref Comp tab lets you specify the reference composition of the fluid that is used for tuning calculations. Tuning Process The tuning process is a series of calculations that is initiated as a task by clicking the Tune button. The first step validates the tuning data specified as follows: l l l l that there's at least one component identified as a wax former. a valid reference composition has been entered. sorting the pairs of temperature/wax mass percent in order of descending temperature. ensure cloud point temperature is greater than any temperature in table of temperature/wax mass percent pairs. If any problem is found the tuning process stops and an appropriate error message appears on the tuning status bar. If the tuning data is valid then the tuning process first does a VLE flash at 15°C and 100 kPa to calculate the liquid composition of the reference stream. This is used as the base composition for all subsequent tuning calculations. If a liquid phase cannot be found in the reference stream at these conditions the tuning calculations fail. The tuning process then continues using an iterative least squares solution method. Progress of the tuning process is output to the main Petro-SIM status bar. When complete the tuning process checks for convergence and displays the result on the tuning status bar. If the tuning process converged then the calculated results on the Tuning data tab are updated. If the tuning process failed to converge the tuning parameters are set to the best values that were obtained. Tuning parameters can be reset to their original values by re-selecting the wax model. Three tuning parameters available for the Chung, Pederson and Conoco wax models and 4 tuning parameters for the AEA model. The tuning process only attempts to tune as many parameters as possible from the specified data (i.e., cloud point + one pair of temperature/wax v 673 Chapter 8: General Unit Operations percent data allows tuning of two parameters - more pairs of temperature/wax percent data points are required to tune additional parameters). In cases where an attempt to tune three or four parameters fails to converge, a second tuning attempt is made automatically for just two tuning parameters. The convergence of the tuning process is checked by looking at the cloud point result since this is the most critical parameter. Generally convergence is achieved when there are one or two pairs of temperature/wax percent data. Given the emphasis placed on achieving the cloud point the calculated results for wax percent can often show greater errors, particularly when there are multiple temperature/wax percent points. You should realize the degree to which the tuning parameters can adjust the temperature/wax percent curve predicted by the models is limited and that hand tuning by changing the number and proportion of wax forming components in the system may be required in some cases. Profes Wax Model The deposition of the wax from the bulk oil onto the pipe wall is assumed to only be due to mass transfer, shear dispersion is not considered to be a significant factor. The rate of deposition is described by: m ′ = k (C wall − C bulk)AMw wax where: m′ = deposition rate (kg/s) k = mass transfer coefficient (mole/m2 s mole Fraction) C = local concentration of wax forming components (mole fraction) Mw wax = molecular weight of wax (kg/mole) A = cross-sectional area (m2 ) The mass transfer coefficient is calculated using the correlation: Sh = 0.015 * Re 0.88Sc 1/3 where: Sc = Re = Sh = 674 v µl ρl D Vl ρl DH µl kDH cD Pipe Segment D = diffusivity of wax in oil (m2 /s) µ = liquid viscosity (kg/ms) ρ = liquid density (kg/m2 ) l k = mass transfer coefficient (mole/m2 s mole fraction) D = hydraulic radius (m) H V = liquid velocity (m/s) l c = liquid molar density (mole/m3 ) The Reynolds number used in these calculations is based on the local liquid velocity and liquid hydraulic radius. Physical properties are taken as the single phase liquid values. The viscosity used is based on the fluid temperature and shear rate at the wall. The difference in concentration of wax forming species between the bulk fluid and the wall, which is the driving force for the deposition of wax is obtained from calculating the equilibrium wax quantities at the two relevant temperatures. These calculations provide a wax deposition rate that is integrated over each time step to give the total quantity of wax laid down on the pipe wall. Modifying the Fittings Database The fittings data base contains VH Factor and FT Factor data taken from Perry. Some of the Factor data are taken from Crane. To add a fitting to the database To add a fitting, open the “fitting.db” file in an ASCII editor and move somewhere in the middle of the file (but make sure you are above the definition of the fittings group). Add the lines: FittingType loopdeloop VHFactor 10.0 Desc “Loop-de-loop!” FT Factor 0.0 DataSource “Add fitting demo” end You do not have to indent the VHFactor, Desc, FTFactor and DataSource lines, it just makes the file neater and easier to read . Next, the fitting needs to be added to the fittings group. Find the line in the file that says “FittingTypeGroup FTG”. Go anywhere between this line and the “end” line and type: AddFitt loopdeloop v 675 Chapter 8: General Unit Operations When you next run Petro-SIM and make a Pipe Segment, the new fitting “Loop-de-loop!” appears in the fittings drop-down list and if you add a “Loop-de-loop!” to the fittings list, it comes up with a K-Factor of 10.0. To take out the fitting, just delete the lines that were previously added. This table details the values in the database. The Data Source column displays the source of the data values. 676 v Description VH Factor FT Factor Swage Angle Pipe 0 0 0 Swage: Abrupt 0 0 180 Swage: 45 degree 0 0 45 Elbow: 45 Std 0 16 0 Crane 410M, A-29 Elbow: 45 Long 0.2 0 0 Perry 5th ed, Table 519 Elbow: 90 Std 0 30 0 Crane 410M, A-29 Elbow: 90 Long 0.45 0 0 Perry 5th ed, Table 519 Bend: 90, r/d 1 0 20 0 Crane 410M, A-29 Bend: 90, r/d 1.5 0 14 0 Crane 410M, A-29 Bend: 90, r/d 2 0 12 0 Crane 410M, A-29 Bend: 90, r/d 3 0 12 0 Crane 410M, A-29 Bend: 90, r/d 4 0 14 0 Crane 410M, A-29 Bend: 90, r/d 6 0 17 0 Crane 410M, A-29 Bend: 90, r/d 8 0 24 0 Crane 410M, A-29 Bend: 90, r/d 10 0 30 0 Crane 410M, A-29 Bend: 90, r/d 12 0 34 0 Crane 410M, A-29 Bend: 90, r/d 14 0 38 0 Crane 410M, A-29 Bend: 90, r/d 16 0 42 0 Crane 410M, A-29 Bend: 90, r/d 20 0 50 0 Crane 410M, A-29 Elbow: 45 Miter 0 60 0 Crane 410M, A-29 Data Source Pipe Segment Description VH Factor FT Factor Swage Angle Data Source Elbow: 90 Miter 0 60 0 Crane 410M, A-29 180 Degree Close Return 0 50 0 Crane 410M, A-29 Tee: Branch Blanked 0 20 0 Crane 410M, A-29 Tee: As Elbow 0 60 0 Crane 410M, A-29 Coupling/Union 0.04 0 0 Perry 5th ed, Table 519 Gate Valve: Open 0.17 0 0 Perry 5th ed, Table 519 Gate Valve: Three Quarter 0.9 0 0 Perry 5th ed, Table 519 Gate Valve: Half 4.5 0 0 Perry 5th ed, Table 519 Gate Valve: One Quarter 24 0 0 Perry 5th ed, Table 519 Gate Valve, Crane: Open 0 8 0 Crane 410M, A-27 Diaphragm Valve: Open 2.3 0 Perry 5th ed, Table 519 Diaphragm Valve: Three Quarter 2.6 0 0 Perry 5th ed, Table 519 Diaphragm Valve: Half 4.3 0 0 Perry 5th ed, Table 519 Diaphragm Valve: One Quarter 21 0 0 Perry 5th ed, Table 519 Globe Valve: Open 6 0 0 Perry 5th ed, Table 519 Globe Valve: Half 9.5 0 0 Perry 5th ed, Table 519 Globe Valve, Crane: Open 0 340 0 Crane 410M, A-27 Angle Valve: Open 2 0 0 Perry 5th ed, Table 519 v 677 Chapter 8: General Unit Operations 678 v Description VH Factor FT Factor Swage Angle Angle Valve, 45 deg: Open 0 55 0 Perry 5th ed, Table 519 Angle Valve, 90 deg: Open 0 150 0 Crane 410M, A-27 Blowoff Valve: Open 3 0 0 Perry 5th ed, Table 519 Plug Cock: Angle 5 0.05 0 0 Perry 5th ed, Table 519 Plug Cock: Angle 10 0.29 0 0 Perry 5th ed, Table 519 Plug Cock: Angle 20 1.56 0 0 Perry 5th ed, Table 519 Plug Cock: Angle 40 17.3 0 0 Perry 5th ed, Table 519 Plug Cock: Angle 60 206 0 0 Perry 5th ed, Table 519 Plug Cock: Open 0 18 0 Crane 410M, A-29 Butterfly Valve: Angle 5 0.24 0 0 Perry 5th ed, Table 519 Butterfly Valve: Angle 10 0.52 0 0 Perry 5th ed, Table 519 Butterfly Valve: Angle 20 1.54 0 0 Perry 5th ed, Table 519 Butterfly Valve: Angle 40 10.8 0 0 Perry 5th ed, Table 519 Butterfly Valve: Angle 60 118 0 0 Perry 5th ed, Table 519 Butterfly Valve: 2-8in, Open 0 45 0 Crane 410M, A-28 Butterfly Valve: 10-14in, Open 0 35 0 Crane 410M, A-28 Butterfly Valve: 16-24in, Open 0 25 0 Crane 410M, A-28 Data Source Pipe Segment Description VH Factor FT Factor Swage Angle Data Source Ball Valve: Open 0 3 0 Crane 410M, A-28 Check Valve: Swing 2 0 0 Perry 5th ed, Table 519 Check Valve: Disk 10 0 0 Perry 5th ed, Table 519 Check Valve: Ball 70 0 0 Perry 5th ed, Table 519 Check Valve: Lift 0 600 0 Crane 410M, A-27 Check Valve: 45 deg Lift 0 55 0 Crane 410M, A-27 Foot Valve 15 0 0 Perry 5th ed, Table 519 Foot Valve: Poppet disk 0 420 0 Crane 410M, A-28 Foot Valve: Hinged disk 0 75 0 Crane 410M, A-28 Water Meter: Disk 7 0 0 Perry 5th ed, Table 519 Water Meter: Piston 15 0 0 Perry 5th ed, Table 519 Water Meter: Rotary 10 0 0 Perry 5th ed, Table 519 Water Meter: Turbine 6 0 0 Perry 5th ed, Table 519 User Defined 0 0 0 User specified A few sections from the “fittings.db” file are shown: FittingType elbow45std VHFactor 0.0 Desc "Elbow: 45 Std" FTFactor 16.0 DataSource "Crane 410M, A-29" end FittingType swage2 VHFactor 0.0 v 679 Chapter 8: General Unit Operations Desc "Swage: 45 degree" SwageAngle 45.0 end ... FittingTypeGroup FTG AddFitt elbow45std ... end This can be broken down, line by line: FittingType elbow45std This defines an object “elbow45std” of type “FittingType”. “FittingType” has three members (parameters): a VH Factor (K-Factor), FT factor or Swage angle and a description. The object name “elbow45std” is only an internal name; it does not appear in any lists or views. VHFactor 0.0 This is the K-Factor for the fitting. When you add a fitting to the fittings list, this is the number that is put in the K-Factor column. Desc “Elbow: 45 Std” This assigns a label (description) to the fitting “elbow45std”. It is this label that is used in the fittings window to select fittings. FTFactor 16.0 This line contains one of the two possible command lines: This is the FT factor for the fitting. When you add a fitting to the fittings list, this is the number that is put in the FT factor column. Swage Angle 45 This command is used to assign the value for the swage angle fitting calculation method. DataSource “Crane 410M, A-29” This tells you the data source. end This tells Petro-SIM that the description of “elbow45std” is done. 680 v Pipe Segment All the fittings are gathered into one group - a “FittingTypeGroup”- to make it easier for PetroSIM to determine what should go where. FittingTypeGroup FTG Same as line 1 above. This defines an object “FTG” of type “FittingTypeGroup”. “FTG” can have many parameters, but they must all be of the same type - FittingType. The FittingTypeGroup is like a container for all the pipe fittings. AddFitt elbow45std This adds the previously defined fitting to the group. Notice that the fitting MUST be defined before it is added to the group. All new fittings should be added last in the database file. When the fittings appear in the drop-down list, they're sorted alphabetically by their Desc parameter. end This tells Petro-SIM that you have added all the fittings you want to the fitting group. New fittings should be added as the last entry in the database. Petro-SIM does not automatically put fittings in the group just because they're defined beforehand. For example, if we had defined “elbow45std” as above, but forgot to add it to the fittings group, there would be no way to access it in the fittings window. Also, the “end” command is very important. If you forget to put an “end” in somewhere in the middle of the fittings.db file, you can get errors that may or may not tell you what's actually wrong. v 681 Chapter 8: General Unit Operations Continuously Stirred Tank Reactor (CSTR) The Continuously Stirred Tank Reactor (CSTR) is a vessel in which kinetic, heterogeneous catalytic and simple rate reactions can be performed. The conversion in the reactor depends on the rate expression of the reactions associated with the reaction type. The inlet stream is assumed to be perfectly (and instantaneously) mixed with the material already in the reactor, so that the outlet stream composition is identical to that of the reactor contents. Given the reactor volume, a consistent rate expression for each reaction and the reaction stoichiometry, the CSTR computes the conversion of each component entering the reactor. Refer also to About Setting Up Reactors in Petro-SIM. 1. To add a CSTR unit operation to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click CSTR (or click and drag it to the flowsheet). A CSTR unit operation is added to the active flowsheet. CSTR PFD view 682 v Continuously Stirred Tank Reactor (CSTR) 3. In the CSTR property view, enter the properties in these tabs: l Design l Reactions l Rating l Worksheet l Dynamics- This tab is available only when working in Dynamics mode. 4. To ignore the CSTR during calculations, check Ignored. Design The CSTR Design tab contains the following pages: Connections The Connections page allows you to connect the feed, product and energy streams to the reactor. The Connections page consists of these objects: Object Input Required Name Optionally, modify the name of the reactor at any time. Inlets Connects a single feed or multiple feed streams to the reactor. You can either type in the name of the stream or, if you have pre-defined the stream, select it from the drop-down list. v 683 Chapter 8: General Unit Operations Object Input Required Vapour Outlet Connects the vapour product stream to the reactor. You can either type in the name of the stream or select it from the drop-down list. At least one product stream is required. Liquid Outlet Connects the liquid product stream to the reactor. You can either type in the name of the stream or select it from the drop-down list. Energy (Optional) Connects or creates an energy stream if one is required for the operation. Parameters The Parameters page allows you to specify the pressure drop, vessel volume, duty and solving behaviour. 684 v Continuously Stirred Tank Reactor (CSTR) Object Description Delta P Contains the pressure drop across the vessel. The pressure drop is defined as: ∆P = P feed − Pv = P feed − Pl P = Pv = Pl where: P = vessel pressure P = pressure of vapour product stream v P = pressure of liquid product stream l P = pressure of feed stream feed ΔP = pressure drop in vessel (Delta P) The default pressure drop across the vessel is zero. P is assumed to be the lowest pressure of all the feed streams. feed The vessel pressure is used in the reaction calculations. Duty If you have attached an energy stream, you can specify whether it is to be used for heating or for cooling by selecting the appropriate radio button. You also have a choice of specifying the applied duty or having Petro-SIM calculate the duty. For the latter case, you must specify an outlet temperature for a reactor product stream. The steady state Reactor energy balance is defined as: Duty = H vapour + Hliquid − H feed where: Duty = heating (+ve) or cooling (-ve) by the optional energy stream H = heat flow of the vapour product stream vapour H = heat flow of the liquid product stream liquid H = heat flow of the feed stream(s) feed The enthalpy basis used by Petro-SIM is equal to the ideal gas enthalpy of formation at 25°C and 1 atm. As a result, the heat of reaction calculation is included in any product/reactant enthalpy difference. Heating /Cooling If you change from Heating to Cooling (or vice-versa), the magnitude of the energy stream does not change. The sign changes in the energy balance. For heating, the duty is added. For cooling, the duty is subtracted. v 685 Chapter 8: General Unit Operations Object Description Volume Specify the total volume of the vessel. The vessel volume, with the liquid level set point, defines the amount of holdup in the vessel. The amount of liquid volume or holdup in the vessel at any time is given by the expression: Holdup=Vessel Volume * PV(% Full) 100 where: PV(%Full) = liquid level in the vessel The vessel volume is necessary to determine the residence time. Liquid Level Displays the liquid level of the reactor expressed as a percentage of the Full Vessel Volume. Liquid Volume This value is calculated from the product of the volume (vessel volume) and liquid level fraction. It is only active when the volume field contains a valid entry. You can also add User Variables and Notes. Rating The CSTR Rating tab contains one page: Sizing The Sizing page allows you to define the relative geometry for the reactor. 686 v Continuously Stirred Tank Reactor (CSTR) If the CSTR has a boot, define the boot dimensions. Reactions Use the CSTR Reactions tab to select a reaction set for the operation. You can also view the results of the solved reactor including the actual conversion of the base component. The actual conversion is calculated as the percentage of the base component that was consumed in the reaction. For more information on Reactions, refer to Kinetic, Heterogeneous Catalytic and Simple Rate reactions. X= N A in − N A out N A in * 100 % where: X = actual % conversion N A in = base component flow rate into the reactor N A out = base component flow rate (same basis as the inlet rate) out of the reactor The CSTR Reactions tab consists of these pages: Details The Details page allows you to attach the appropriate reaction set to the operation. v 687 Chapter 8: General Unit Operations The selected reaction set can contain only Kinetic, Heterogeneous Catalytic and Simple Rate reactions. 688 v Select... To... Reaction Set Select the reaction set you want to use in the reactor. Reaction Select the reaction whose results you want to view. Continuously Stirred Tank Reactor (CSTR) Select... To... View Reaction Open the property view where you can edit the reaction globally for the selected reaction: l l l Specifics Kinetic Heterogeneous Catalytic Simple Rate Select: Stoichiometry Examine the components involved in the selected reaction, their molecular weights and their stoichiometric coefficients. The Balance Error (for the Reaction Stoichiometry) and the Reaction Heat (heat of Reaction at 25°C) are also shown for the current reaction. Basis View base component, the reaction rate parameters (A, E, ß, A’, E’, and ß’) and reaction phase for each reaction in the attached set. v 689 Chapter 8: General Unit Operations Select... To... To view the properties for a specific reaction,select the reaction from the Reaction drop-down list. Changes can be made to the reaction rate parameters (frequency factor, A, activation energy, E and ß), but these changes are reflected only in the active reactor. The changes do not affect the global reaction. To return the global reaction values to its default value, check the Use Default check box. If you've made a change to the forward reaction activation energy (E), the Use Default check box for E is not enabled. Check it to return to the global E value. Results The CSTR Results page displays the results of a converged reactor. 690 v Continuously Stirred Tank Reactor (CSTR) From the Reaction Results Summary select: Reaction Extents The Reaction Extents option displays the results for a converged reactor. Result Field Description Actual % Conversion Displays the percentage of the base component in the feed streams that have been consumed in the reaction. Base Component The reactant to which the conversion is applied. Rxn Extent Lists the molar rate of consumption of the base component. v 691 Chapter 8: General Unit Operations Reaction Balance The Reaction Balance option provides an overall component summary for the CSTR. All components that display in the fluid package are displayed. Values display after the solution of the reactor has converged. The total inflow rate, the total reacted rate and total outflow rate for each component are provided on a molar basis. Negative values indicate the consumption of a reactant, while positive values indicate the display of a product. 692 v Plug Flow Reactor (PFR) Plug Flow Reactor (PFR) The Plug Flow Reactor (PFR) or Tubular Reactor generally consists of a bank of cylindrical pipes or tubes. Refer also to About Setting Up Reactors in Petro-SIM. 1. To add a PFR unit operation to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click PFR (or click and drag it to the flowsheet). A PFR unit operation is added to the active flowsheet. PFR PFD view 3. In the PFR property view, enter the properties in these tabs: l Design l Reactions l Rating l Worksheet v 693 Chapter 8: General Unit Operations l l Performance Dynamics- This tab is available only when working in Dynamics mode. 4. To ignore the PFR during calculations, check Ignored. The flow field is modelled as plug flow, implying that the stream is radially isotropic (without mass or energy gradients). This also implies that axial mixing is negligible. As the reactants flow the length of the reactor, they are continually consumed, hence, there is an axial variation in concentration. Since reaction rate is a function of concentration, the reaction rate also varies axially (except for zero-order reactions). To obtain the solution for the PFR (axial profiles of compositions, temperature, etc.), the reactor is divided into several subvolumes. Within each subvolume, the reaction rate is considered to be spatially uniform. A mole balance is done in each subvolume j: Fj 0 − Fj + ∫ r j d V = dN j dr v Because the reaction rate is considered spatially uniform in each subvolume, the third term reduces to rjV. At steady state, the right side of this balance equals zero, and the equation reduces to: Fj = Fj 0 + r j V Design The PFR Design tab consists of the following pages: Connections You can specify the name of the reactor, the feed(s) stream, product stream and energy stream on the Connections page. 694 v Plug Flow Reactor (PFR) If you do not provide an energy stream, the operation is considered to be adiabatic. The objects on the Connections page include the following: Object Input Required Inlets The reactor feed stream. Outlet The reactor product stream. Energy (Optional) You are not required to provide an energy stream Under those circumstances, Petro-SIM assumes that the operation is adiabatic. Parameters Use the Parameters page to define the pressure drop and duty parameters. v 695 Chapter 8: General Unit Operations Pressure Drop Parameters In the Pressure Drop Parameters group, you can click one of the available radio buttons for the determination of the total pressure drop across the reactor. Radio Button Description User Specified You must specify a pressure drop in the pressure drop (Delta P) field. Ergun Equation Petro-SIM uses the Ergun equation to calculate the pressure drop across the PFR. The equation parameters include values that you specify for the PFR dimensions and feed streams: ∆Pg c φsD p ϵ 3 150(1 − ϵ) = + 1.75 L ρV 2 1 − ϵ φsD pVρ / µ where: ΔP = pressure drop across the reactor g = Newton’s-law proportionality factor for the gravitational force unit c L = reactor length φs = particle sphericity D = particle (catalyst) diameter p ρ = fluid density 696 v Plug Flow Reactor (PFR) Radio Button Description V = superficial or empty tower fluid velocity ε = void fraction µ = fluid viscosity When you select Ergun Equation , the Pressure Drop (Delta P) field changes color from blue to black, indicating a value calculated by Petro-SIM. If you select Ergun Equation for a PFR with no catalyst (solid), Petro-SIM sets ΔP = 0. Duty For the PFR heat transfer calculations, select one of the following options. Duty Parameter Description Formula Petro-SIM calculates the energy stream duty after you specify further heat transfer information on the Heat Transfer Page. The two fields below the radio buttons show the Energy Stream that is attached on the Connections page and the Calculated Duty value. Direct Q Value You can directly specify a duty value for the energy stream. You can specify whether the energy stream is heating or cooling by selecting the appropriate radio button. This does not affect the sign of the duty stream. Rather, if the energy stream is heating, then the duty is added to the feed. If Cooling is chosen, the duty is subtracted. Heat Transfer The two groups available on the PFR Heat Transfer page let you specify parameters used in the determination of the duty. Your selection in the SS Duty Calculation Option group is also transferred to the Heat Transfer group on the Parameters page. Formula Select Formula to instruct Petro-SIM to rigorously calculate the duty of each PFR subvolume using local heat transfer coefficients for the inside and the outside of each PFR tube using the Ergun equation and Heat Transfer equation. v 697 Chapter 8: General Unit Operations For the Formula option, you must have an energy stream attached to the PFR. You cannot use this option while operating adiabatically. ( ) Q j = U j A T bulkj − T outj Resistance of the tube wall to heat transfer is neglected. where: Q = heat transfer for subvolume j j U = overall heat transfer coefficient for subvolume j j A = surface area of the PFR tube T T bulkj outj = bulk temperature of the fluid = temperature outside of the PFR tube (utility fluid) x 1 1 1 = + + w U h out hw km where: U = overall heat transfer coefficient 698 v Plug Flow Reactor (PFR) h out = local heat transfer coefficient for the outside (utility fluid) h = local heat transfer coefficient inside the PFR tube w xw k m = heat transfer term for the tube wall typically negligible (ignored in calculations) The final term in heat transfer coefficient equation, which represents the thickness of the tube divided by the thermal conductivity of the tube material, is believed negligible and ignored in the PFR calculations. In each subvolume, heat is being transferred radially between the PFR fluid and the utility fluid. Heat Medium Side Heat Transfer Infos Group If you specify a heat flow on the Energy Stream property view and select the Formula option on the Heat Transfer page, inconsistencies display in the solution. You cannot specify a duty and have Petro-SIM calculate the same duty. In the Heat Medium Side Heat Transfer Infos group, you can modify the parameters used to calculate the duty (Q ) for the outside of each PFR subvolume. The parameters include the j following: Parameter Formula Variable Input Required Wall Heat Transfer Coefficient h Mole Flow m Specify a value for the local heat transfer coefficient. Since the UA value, in this case the U being the local heat transfer coefficient, is constant, changes made to the specified length, diameter, or number of tubes (on the Dimensions page) affects h out. Molar flow of the energy stream utility fluid. Heat Capacity C Heat capacity of the energy stream utility fluid. Inlet Temperature T out p Calculated Duty Q j The temperature of the utility fluid entering the PFR. Duty calculated for each PFR subvolume. v 699 Chapter 8: General Unit Operations The equation used to determine the temperature of the utility fluid entering each subvolume j is: Q j = mρC p (T j − T j +1) Tube Side Heat Transfer Info Group In the Tube Side Heat Transfer Info group, you can select the method for determining the inside local heat transfer coefficient (h ) by modifying one of these options. w Select... To... View User Specify a value for the local heat transfer coefficient in the User Specified input field. Empirical Specify coefficients for the empirical equation, which relates the heat transfer coefficient to the flow rate of the PFR fluid using the equation: hw A * FlowB You can also choose the basis for the equation as Molar, Mass or Volume. Standard Specify coefficients for the calculation of the Nusselt number, which is then used to calculate the local heat transfer coefficient: Nu = A * ReB * Pr C Bhw= 700 v N uk g Dp Plug Flow Reactor (PFR) Direct Q Value Select Direct Q Value to display the Heat Transfer options. Object Description Energy Stream The name of the duty stream. Duty The duty value to be specified in the energy stream. Heating/Cooling Selecting one of these options does not affect the sign of the duty stream. Rather, if the energy stream is Heating, then the duty is added to the feed. If Cooling is chosen, the duty is subtracted. You can also add User Variables and Notes. Reactions The PFR Reactions tab consists of the following pages: Overall The Overall page is made up of three groups. v 701 Chapter 8: General Unit Operations Reaction Info In the Reaction Info group, you specify the following: l l The reaction set to be used The segment initialization method From the Reaction Set drop-down list, select the reaction set you want to use for the PFR. The Reaction Set you want to use must be attached to the fluid package you are using in this reactor. The PFR is split into segments by the reactor solver algorithm. Petro-SIM obtains a solution in each segment of the reactor. The segment reactions may be initialized by: 702 v Plug Flow Reactor (PFR) Initialization Option Description Current Initializes from the most recent solution of the current segment. Previous Initializes from the most recent solution of the previous segment. Re-init Re-initializes the current segment reaction calculations. Integration Information The Integration Information group contains these fields: Field Description Number of Segments The number of segments into which you want to split the PFR. Minimum Step Fraction The minimum fraction into which an unresolved segment splits. Minimum Step Length The product of the Reactor Length and the Minimum Step Fraction. During each segment calculation, Petro-SIM tries to calculate a solution over the complete segment length. The length of each segment stays constant during the calculations. If a solution cannot be obtained for an individual segment, it is divided into smaller sections until a solution is reached. This does not affect the other segments. If a solution cannot be obtained, the current segment is halved, and Petro-SIM attempts to determine a solution over the first half of the segment. The segment continues to be halved until a solution is obtained, at which point the remaining portion of the segment is calculated. If the segment is divided to the point where its length is less than the minimum step length, calculations stop. v 703 Chapter 8: General Unit Operations Catalyst Data If you specified a void fraction less than one on the Rating tab, the Catalyst Data group displays. The following information must be specified: Field Description Particle Diameter The mean diameter of the catalyst particles. The default particle diameter is 0.001 m. Particle Sphericity This is defined as the surface area of a sphere having the same volume as the particle divided by the surface area of the particle. A perfectly spherical particle has a sphericity of 1. The Particle Diameter and Sphericity are used to calculate the pressure drop (in the Ergun pressure drop equation) if it is not specified. Solid Density The density of the solid portion of the particle, including the catalyst pore space (microparticle voidage). This is the mass of the particle divided by the overall volume of the particle, and therefore includes the pore space. The default is 2500 kg/m3. Bulk Density Equal to the solid density multiplied by one minus the void fraction. ρb = ρs (1 − ϵma ) where: ρ = bulk density b ρ = solid density s ε = macroparticle voidage (void fraction) ma Solid Heat Capacity Used to determine the solid enthalpy holdup in dynamics. The bulk density is also required in this calculation. Details You can manipulate the reactions attached to the selected reactions set on the Details page. 704 v Plug Flow Reactor (PFR) The Details page consists of the three following objects: Object Description Reaction Allows you to select the reaction you want to use in the reactor. View Reaction Opens the Reaction property view where you can edit the reaction. This affects all other implementations of the selected reaction. Specifics Select:. Stoichiometry The Stoichiometry group allows you to examine the components involved in the currently selected reaction, their molecular weights and their stoichiometric coefficients. v 705 Chapter 8: General Unit Operations Object Description To affect change in the reaction over the entire simulation, click View Reaction to make the changes in the Reaction property view . The Balance Error (for the reaction stoichiometry) and the Reaction Heat (Heat of Reaction at 25°C) are also shown for the current reaction. Basis In the Basis group, you can view the base component and the rate expression parameters. You can make changes to these parameters. These changes only affect the current implementation of the reaction and are not affected by other reactors using the reaction set or reaction. Results The Results page displays the results of a converged reactor. The page consists of the Reaction Balance group, which contains the following options: Reaction Extents Select the Reaction Extents option to display the results for the converged reactor. 706 v Plug Flow Reactor (PFR) Result Field Description Actual % Conversion Displays the percentage of the base component in the feed stream(s) consumed in the reaction. Base Component The reactant to which the conversion is applied. Rxn Extent Lists the molar rate consumption of the base component. Reaction Balance Select the Reaction Balance option to provide an overall component summary for the PFR. All components that display in the connected component list are shown. v 707 Chapter 8: General Unit Operations Any changes made to the global reaction affect all reaction sets to which the reaction is attached, provided local changes have not been made. Values display after the solution of the reactor has converged. The Total Inflow rate, the Total Reacted rate and the Total Outflow rate for each component are provided on a molar basis. Negative values indicate the consumption of a reactant, while positive values indicate the display of a product. Rating The PFR Rating tab contains this page. Sizing Use the Sizing page to define the Tube Dimensions and Packing. 708 v Plug Flow Reactor (PFR) Performance The Performance tab contains five pages that allow you to examine various axial profiles in the PFR. Each page consists of a table containing the relevant performance data and a Plot button that converts the data to a graphical form. The Reactor Length is always plotted on the x-axis. The data points are taken in the middle of each reactor segment, and correspond to the number of reactor segments you specified. Conditions The Conditions page allows you to view a table of the various physical parameters including Temperature, Pressure, Vapour Fraction, Duty, Enthalpy, Entropy, Inside HTC and Outside HTC as a function of the Reactor Length. v 709 Chapter 8: General Unit Operations Click the Plot button to display the selected Physical parameter as a function of the Reactor Length. Flows The following overall flow types can be viewed in a table or plotted as a function of the Reactor Length: l l 710 v Material Flow: Molar, Mass or Volume Energy: Heat Plug Flow Reactor (PFR) Rxn Rates (Reaction Rates) You can view either Reaction Rate or Component Production Rate data as a function of the Reactor Length on the Rxn Rates page. Although only one reaction set can be attached to the PFR, it can contain multiple reactions. v 711 Chapter 8: General Unit Operations Transport The Transport page displays these Transport properties as a function of the Reactor Length. l l l l l l 712 v Viscosity Molar Weight Mass Density Heat Capacity Surface Tension Z Factor Plug Flow Reactor (PFR) Compositions You can view individual component profiles using one of the following composition bases: l l l l l l l Molar Flow Mass Flow Liquid Volume Flow Fraction Mole Fraction Mass Fraction Liquid Volume Fraction v 713 Chapter 8: General Unit Operations 714 v Gibbs Reactor Gibbs Reactor The Gibbs Reactor calculates the exiting compositions such that the phase and chemical equilibria of the outlet streams are attained. The Gibbs reactor does not need to make use of a specified reaction stoichiometry to compute the outlet stream composition. The condition that the Gibbs free energy of the reacting system is at a minimum at equilibrium is used to calculate the product mixture composition. As with the equilibrium reactor, neither pure components nor the reaction mixture are assumed to behave ideally. The versatility of the Gibbs Reactor allows it to function solely as a separator, reactor that minimizes the Gibbs free energy without an attached reaction set, or reactor which accepts equilibrium reactions. When a reaction set is attached, the stoichiometry involved in the reactions is used in the Gibbs Reactor calculations. Refer also to About Setting Up Reactors in Petro-SIM. 1. To add a Gibbs Reactor to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Gibbs Reactor (or click and drag it to the flowsheet). A Gibbs Reactor unit operation is added to the active flowsheet. v 715 Chapter 8: General Unit Operations Gibbs Reactor PFD view 3. In the Gibbs Reactor property view, enter the properties in these tabs: l Design l Reactions l Rating l Worksheet l Dynamics- This tab is available only when working in Dynamics mode. 4. To ignore the Gibbs Reactor during calculations, check Ignored. Design The Gibbs Reactor Design tab contains the following pages: Connections Specify the name of the reactor, feed streams, product streams, and energy stream on the Connections page. 716 v Gibbs Reactor Parameters Use the Parameters page to define the calculations for the pressure drop and heat transfer. Object Description Delta P Contains the pressure drop across the vessel. The pressure drop is defined as: ∆P = P feed − Pv = P feed − Pl P = Pv = Pl where: P = vessel pressure P = pressure of vapour product stream v P = pressure of liquid product stream l P = pressure of feed stream feed ΔP = pressure drop in vessel (Delta P) The default pressure drop across the vessel is zero. P is assumed to be the lowest pressure of all the feed streams. feed The vessel pressure is used in the reaction calculations. Duty If you have attached an energy stream, you can specify whether it is to be used for heating or for cooling by selecting the appropriate radio button. You also have a choice of specifying the applied duty or having Petro-SIM calculate the duty. For the latter case, you must specify an outlet temperature for a reactor v 717 Chapter 8: General Unit Operations Object Description product stream. The steady state Reactor energy balance is defined as: Duty = H vapour + Hliquid − H feed where: Duty = heating (+ve) or cooling (-ve) by the optional energy stream H = heat flow of the vapour product stream vapour H = heat flow of the liquid product stream liquid H = heat flow of the feed stream(s) feed The enthalpy basis used by Petro-SIM is equal to the ideal gas enthalpy of formation at 25°C and 1 atm. As a result, the heat of reaction calculation is included in any product/reactant enthalpy difference. Heating /Cooling If you change from Heating to Cooling (or vice-versa), the magnitude of the energy stream does not change. The sign changes in the energy balance. For heating, the duty is added. For cooling, the duty is subtracted. Volume Specify the total volume of the vessel. The vessel volume, with the liquid level set point, defines the amount of holdup in the vessel. The amount of liquid volume or holdup in the vessel at any time is given by the expression: Holdup=Vessel Volume * PV(% Full) 100 where: PV(%Full) = liquid level in the vessel The vessel volume is necessary to determine the residence time. Liquid Level Displays the liquid level of the reactor expressed as a percentage of the Full Vessel Volume. Liquid Volume This value is calculated from the product of the volume (vessel volume) and liquid level fraction. It is only active when the volume field contains a valid entry. You can also add User Variables and Notes. 718 v Gibbs Reactor Reactions The Gibbs Reactions tab consists of two pages: Overall The Overall page allows you to select the Reactor Type. The objects that display depend on which reactor you selected. You can then attach a reaction set if necessary and you can specify the vessel parameters on the Rating tab. In the Reactor Type group, select the reactor to define the method Petro-SIM uses to solve the Gibbs Reactor. v 719 Chapter 8: General Unit Operations Radio Button Description Gibbs Reactions Only No reaction set is required as Petro-SIM solves the system by minimizing the Gibbs free energy while attaining phase and chemical equilibrium. You can also customize the maximum iteration number and equilibrium error tolerance in the Solving Option group. Specify Equilibrium Reactions Displays the Equilibrium Reaction Sets group. When a reaction set is attached, the Gibbs Reactor is solved using the stoichiometry of the reactions involved. The Gibbs minimization function uses the extents of the attached reactions while setting any unknowns to zero. NO Reactions (=Separator) The Gibbs Reactor is solved as a separator operation, concerned only with phase equilibrium in the outlet streams. Since the Gibbs reactor allows equilibrium reactions to be attached, it can serve as an alternative to the equilibrium reactor in some cases. This is typically only true for very simple reactions. If there are multiple reactions, the Gibbs reactor will allow reactions between components in the different equilibrium reactions and hence the results may differ from an equilibrium reactor. Details The Details page contains two options: 720 v Gibbs Reactor Flow Specs Select the Flow Specs option to display the component feed and product flow rates on a molar basis. You can also designate any of the components as inert or specify a rate of production for a component. Inert species are excluded from the Gibbs free energy minimization calculations. When the Inerts check box is selected for a component, values of 1 and 0 display respectively in the associated Frac Spec and Fixed Spec cells, which indicates that the component feed flow rate equals the product flow rate. You may want to specify the rate of production of any component in your reactor as a constraint on the equilibrium composition. The component product flow rate is calculated, based on your input of a Frac Spec value and a Fixed Spec value: Total Prod = FracSpec * Total Feed + FixedSpec The Gibbs Reactor attempts to meet that flow rate in calculating the composition of the outlet stream. If the constraint cannot be met, a message displays alerting you to that effect. Atom Matrix Select the Atom Matrix option to specify the atomic composition of any species for which the formula is unknown or unrecognized. v 721 Chapter 8: General Unit Operations The atomic matrix input form displays all components in the case with their atomic composition as understood by Petro-SIM. You can enter the composition of an unrecognized compound or to correct the atomic composition of any compound. Rating The Gibbs Rating tab contains one page: Sizing Use the Sizing page to define the reactor's geometry. If the reactor has a boot, define its boot dimensions. 722 v Equilibrium Reactor Equilibrium Reactor The Equilibrium Reactor is a vessel that models equilibrium reactions. The outlet streams of the reactor are in a state of chemical and physical equilibrium. The reaction set that you attach to the Equilibrium Reactor can contain an unlimited number of equilibrium reactions that are simultaneously or sequentially solved. Neither the components nor the mixing process need be ideal, since Petro-SIM can compute the chemical activity of each component in the mixture based on mixture and pure component fugacities. Refer to Equilibrium Reaction for details on creating and installing equilibrium reactions. You can also examine the actual conversion, base component, equilibrium constant, and the reaction extent for each reaction in the selected reaction set. The conversion, the equilibrium constant and the extent are all calculated based on the equilibrium reaction information that you provided when the reaction set was created. Refer also to About Setting Up Reactors in Petro-SIM. 1. To add an Equilibrium Reactor to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Equilibrium Reactor (or click and drag it to the flowsheet). An Equilibrium Reactor unit operation is added to the active flowsheet. v 723 Chapter 8: General Unit Operations Equilibrium Reactor PFD view 3. In the Equilibrium Reactor property view, enter the properties in these tabs: l Design l Reactions l Rating l Worksheet l Dynamics - This tab is available only when working in Dynamics mode 4. To ignore the Equilibrium Reactor during calculations, check Ignored. Design Modify the Equilibrium Reactor Design tab settings on these pages: Connections Specify the name of the reactor, the feed(s) stream, product stream and energy stream on the Connections page. 724 v Equilibrium Reactor Parameters Use the Parameters page to define the calculations for the pressure drop and heat transfer. Object Description Delta P Contains the pressure drop across the vessel. The pressure drop is defined as: ∆P = P feed − Pv = P feed − Pl P = Pv = Pl where: P = vessel pressure P = pressure of vapour product stream v P = pressure of liquid product stream l P = pressure of feed stream feed ΔP = pressure drop in vessel (Delta P) The default pressure drop across the vessel is zero. P is assumed to be the lowest pressure of all the feed streams. feed The vessel pressure is used in the reaction calculations. Duty If you have attached an energy stream, you can specify whether it is to be used for heating or for cooling by selecting the appropriate radio button. You also have a choice of specifying the applied duty or having Petro-SIM calculate the duty. For the latter case, you must specify an outlet temperature for a reactor v 725 Chapter 8: General Unit Operations Object Description product stream. The steady state Reactor energy balance is defined as: Duty = H vapour + Hliquid − H feed where: Duty = heating (+ve) or cooling (-ve) by the optional energy stream H = heat flow of the vapour product stream vapour H = heat flow of the liquid product stream liquid H = heat flow of the feed stream(s) feed The enthalpy basis used by Petro-SIM is equal to the ideal gas enthalpy of formation at 25°C and 1 atm. As a result, the heat of reaction calculation is included in any product/reactant enthalpy difference. Heating /Cooling If you change from Heating to Cooling (or vice-versa), the magnitude of the energy stream does not change. The sign changes in the energy balance. For heating, the duty is added. For cooling, the duty is subtracted. Volume Specify the total volume of the vessel. The vessel volume, with the liquid level set point, defines the amount of holdup in the vessel. The amount of liquid volume or holdup in the vessel at any time is given by the expression: Holdup=Vessel Volume * PV(% Full) 100 where: PV(%Full) = liquid level in the vessel The vessel volume is necessary to determine the residence time. Liquid Level Displays the liquid level of the reactor expressed as a percentage of the Full Vessel Volume. Liquid Volume This value is calculated from the product of the volume (vessel volume) and liquid level fraction. It is only active when the volume field contains a valid entry. You can also add User Variables and Notes. 726 v Equilibrium Reactor Reactions The Equilibrium Reactor Reactions tab contains these pages: Details The Details page displays the data for the selected Reaction Set and Reaction. Selec t View RXN to modify the reaction. Select one of these options: Stoichiometry Select the Stoichiometry option to view the stoichiometric formula for the currently selected Reaction. Changes made to the global reaction affect all reaction sets that contain the reaction, and thus all operations to which the reaction set is attached. The Balance Error (for the reaction stoichiometry) and the reaction heat (heat of reaction at 25°C) are also shown for the current reaction. Basis Select the Basis option to view or locally edit various information for each reaction in the reaction set including the following: l l l Basis for the equilibrium calculations Phase in which the reaction occurs Temperature approach of the equilibrium composition v 727 Chapter 8: General Unit Operations The temperature range for the equilibrium constant and the source for the calculation of the equilibrium constant is also shown. Refer to Equilibrium Reaction for details on equilibrium constant source. Keq Select the Keq option to view the Ln(keq) group and K-Table. The Ln(keq) group displays the Ln (Keq) relationship that may vary depending upon the Ln(K) source value selected for the reaction. When you select the Ln(Keq) Equation option, the parameters of the equilibrium constant equation are displayed. These values are either specified when the reaction was created or are calculated by Petro-SIM. If a fixed equilibrium constant was provided, it's shown here. 728 v Equilibrium Reactor Any of the parameters in the Ln(K) equation group can be modified on this page. Changes made to the parameters only affect the selected reaction in the current reactor. After a change has been made, you can have Petro-SIM return the original calculated value by clicking the appropriate Use Default check box. Approach Select the Approach option to view the Fractional Approach group and the Temperature Approach group. For each reaction in the reaction set, a fractional approach equation as a function of temperature is provided. Any of the parameters in the Approach % equation can be modified on this page. Changes made to the parameters only affect the selected reaction in the current reactor. After a change has been made, you can have Petro-SIM return the original calculated value by selecting the appropriate Use Default check box. To edit a reaction, click View Rxn. Refer to Equilibrium Reaction for more information. Results The Results page displays the results of a converged reactor. You can change the specified conversion for a reaction directly on this page. The type of results displayed depends on the radio button selected. Any changes made to the global reaction affect all reaction sets to which the reaction is attached, provided local changes have not been made. v 729 Chapter 8: General Unit Operations The page consists of the Reaction Balance group, which contains the following options: Reaction Extents Select the Reaction Extents option to display the results for a converged reactor. Result Field Description Actual % Conversion Displays the percentage of base component in the feed stream(s) that has been consumed in the reaction. The actual conversion is calculated as the percentage of the base component that was consumed in the reaction. X= N A in − N Aout N Ain * 100 % where: X = actual % conversion NAin = base component flow rate into the reactor NAout = base component flow rate (same basis as the inlet rate) out of the reactor Base Component The reactant to which the conversion is applied. Eqm Const. 730 v The equilibrium constant is calculated at the reactor temperature by: Equilibrium Reactor Result Field Description B lnK  = A + + C lnT  + DT T     where: T = reactor temperature, K A, B, C, D = equation parameters The four parameters in the Eqm Const. equation are calculated by Petro-SIM if they are not specified during the installation of the equilibrium reaction. The four parameters for each equilibrium equation are listed on the Rxn Ln(K) page. Rxn Extent Lists the molar rate consumption of the base component. Reaction Balance Select the Reaction Balance option to view an overall Component Summary for the equilibrium reactor. All components that display in the component list related to the fluid package are shown. Values display after the solution of reactor has converged. The Total Inflow rate, the Total Reacted rate, and the Total Outflow rate for each component are provided on a molar basis. Negative values indicate the consumption of a reactant, while positive values indicate the display of a product. v 731 Chapter 8: General Unit Operations Rating The Equilibrium Reactor Rating tab contains this page: Sizing Use the Sizing page to define the reactor's geometry. If the reactor has a boot, define its boot dimensions. 732 v Conversion Reactor Conversion Reactor The Conversion Reactor is a vessel in which conversion reactions are performed. Each reaction proceeds until the specified conversion is attained or until a limiting reactant is depleted. Refer also to About Setting Up Reactors in Petro-SIM. 1. To add a Conversion Reactor unit operation to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Conversion Reactor(or click and drag it to the flowsheet). A Conversion Reactor unit operation is added to the active flowsheet. Conversion Reactor PFD view 3. In the Conversion Reactor property view, enter the properties in these tabs: l Design l Reactions v 733 Chapter 8: General Unit Operations l l l Rating Worksheet Dynamics- This tab is available only when working in Dynamics mode. 4. To ignore the Conversion Reactor during calculations, check Ignored. Design The Conversion Reactor Design tab contains the following pages. Connections Specify the name of the reactor, the feed streams (Inlets), energy stream (optional), Vapour Outlet and Liquid Outlet on the Connections page. Parameters Use the Parameters page to define the calculations for the pressure drop and heat transfer. 734 v Conversion Reactor Object Description Delta P Contains the pressure drop across the vessel. The pressure drop is defined as: ∆P = P feed − Pv = P feed − Pl P = Pv = Pl where: P = vessel pressure P = pressure of vapour product stream v P = pressure of liquid product stream l P = pressure of feed stream feed ΔP = pressure drop in vessel (Delta P) The default pressure drop across the vessel is zero. P is assumed to be the lowest pressure of all the feed streams. feed The vessel pressure is used in the reaction calculations. Duty If you have attached an energy stream, you can specify whether it is to be used for heating or for cooling by selecting the appropriate radio button. You also have a choice of specifying the applied duty or having Petro-SIM calculate the duty. For the latter case, you must specify an outlet temperature for a reactor product stream. The steady state Reactor energy balance is defined as: Duty = H vapour + Hliquid − H feed v 735 Chapter 8: General Unit Operations Object Description where: Duty = heating (+ve) or cooling (-ve) by the optional energy stream H = heat flow of the vapour product stream vapour H = heat flow of the liquid product stream liquid H = heat flow of the feed stream(s) feed The enthalpy basis used by Petro-SIM is equal to the ideal gas enthalpy of formation at 25°C and 1 atm. As a result, the heat of reaction calculation is included in any product/reactant enthalpy difference. Heating /Cooling If you change from Heating to Cooling (or vice-versa), the magnitude of the energy stream does not change. The sign changes in the energy balance. For heating, the duty is added. For cooling, the duty is subtracted. Volume Specify the total volume of the vessel. The vessel volume, with the liquid level set point, defines the amount of holdup in the vessel. The amount of liquid volume or holdup in the vessel at any time is given by the expression: Holdup=Vessel Volume * PV(% Full) 100 where: PV(%Full) = liquid level in the vessel The vessel volume is necessary to determine the residence time. Liquid Level Displays the liquid level of the reactor expressed as a percentage of the Full Vessel Volume. Liquid Volume This value is calculated from the product of the volume (vessel volume) and liquid level fraction. It is only active when the volume field contains a valid entry. You can also add User Variables and Notes. Reactions The Conversion Reactor Reactions tab is made up of these pages. Details Use the the Details page to attach the reaction set to the operation and specify the conversion for 736 v Conversion Reactor each reaction in the set. The reaction set can contain only conversion reactions. Refer also to About Setting Up Reactors in Petro-SIM. The Details page consists of these objects: Object Description Reaction Set Select the appropriate conversion reaction set. Reaction Select the appropriate conversion reaction from the selected reaction set. View Reaction button Open the Reaction property view for the reaction currently selected in the reaction drop-down list where you can edit the reaction. Choose one of these options to toggle between the Stoichiometry, Basis, and Conversion groups: Stoichiometry Select Stoichiometry to examine the components involved in the selected reaction, their molecular weights, and their stoichiometric coefficients. v 737 Chapter 8: General Unit Operations The Balance Error (for the Reaction Stoichiometry) and the Reaction Heat (heat of reaction at 25°C) are also shown for the current reaction. Basis Select Basis to view the base component, conversion, and reaction phase for each reaction in the reaction set. Conversion Select Conversion to implement a conversion model based on the conversion (%) equation listed in the Fractional Conversion Equation group. In the Fractional Conversion Equation group, parameters shown in red or blue, indicate that the variable can be cloned as local variables belonging to the conversion reactor. Therefore, you can either use the parameters specified in the reactions from the attached reaction set by clicking the Use Default check box or specifying the values locally. Results The Results page displays the results of a converged reactor. The page consists of the Reactor Results Summary group that contains two options: 738 v Conversion Reactor Reaction Extents Select Reaction Extents to display the results for the converged reactor. Any changes made to the global reactions affect all Reaction Sets to which the reaction is attached, provided local changes have not been made. The Reactor Results Summary group displays the results for a converged reactor: Result Field Description Rank Displays the current rank of the reaction. For multiple reactions, lower ranked reactions occur first. Actual % Conversion Displays the percentage of the base component in the feed stream(s) that has been consumed in the reaction. Base Component The reactant on which the calculation conversion is based. Rxn Extent Lists the molar rate consumption of the base component. Actual conversion values may not always match the specified conversion values. A reaction may proceed but then be halted when one or more limiting reactants are exhausted. The sum of the specified conversions for lower ranking reactions may be 100%, so all of the remaining base component can be consumed by a higher ranking reaction, provided a limiting reactant is not consumed beforehand. All of the base component may be consumed, and this is reflected in the actual conversion totalling 100%. Reaction Balance Select Reaction Balance to view an overall component summary for the Conversion Reactor. All components that display in the fluid package are shown. v 739 Chapter 8: General Unit Operations Values display after the solution of the reactor has converged. The Total Inflow rate, (reacted) rate, and Total Outflow rate for each component are provided on a molar basis. Negative values indicate the consumption of a reactant, while positive values indicate the display of a product. Rating The Conversion Reactor Rating tab contains this page: Sizing Use the Sizing page to define the reactor's geometry. If the reactor has a boot, define its boot dimensions. 740 v Gas Turbine Gas Turbine The Gas Turbine unit operation is used to model the complete process in the gas combustion turbine that follows the Brayton cycle. The unit operation models the following: l l l The compressor, where ambient air (state 1) is pressurized to state 2. The combustor, where fuel is added to heat the compressed air to state 3. The turbine, in which the heated gases are expanded back to atmospheric pressure (state 4) to generate power for electricity production or to supply mechanical shaft power. Refer also to these reference topics: l l l l l l l Single Shaft and Twin Shaft Gas Turbines Gas Turbine Theory Principal Irreversibilities and Losses Solution Method Part Load Operation Steam Injection Compressed Air Extraction 1. To add a Gas Turbine to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Gas Turbine (or click and drag it to the flowsheet). A Gas Turbine is added to the active flowsheet. v 741 Chapter 8: General Unit Operations 3. In the Gas Turbine property view, enter the properties in these tabs: l Design l Rating l Worksheet l Dynamics - only available in Dynamics mode. 4. To ignore the Gas Turbine during calculations, check Ignored. Design The Gas Turbine Design tab contains the following pages: Connections The Connections page lets you specify the name of the operation, the Shaft type, the Air stream, Fuel stream, Exhaust stream and Power Stream. You can also specify the optional NOx Steam Injection stream, Power up Steam Injection stream and Compressed Air stream. You can open the individual worksheet for the air stream to define its properties. Petro-SIM will calculate the composition of the air stream automatically, if you set the stream type to air and specify the relative humidity and temperature. It will also calculate the pressure if you specify the altitude.Refer to the Worksheet tab for more information. These stream connections refer to the Rating Case. For the Design Case, the Air and Fuel streams are defined internally but if necessary, alternative Fuel and Air streams for the design case can be specified on the parameters' page. Air Extraction and Injection steam streams are not allowed for the Design Case. Parameters The data shown on the Parameters page refers to the Design Case. You need to specify the 742 v Gas Turbine Comp Pressure Ratio, Design Heat Rate (1/Thermal Efficiency), Design GT Power and Design GT Exhaust Temperature as these are used to model the gas turbine for the design case. PetroSIM provides default values as sample data but you need to specify the actual data for the gas turbine that you are modelling. If the parameters provided for your gas turbine are based on full load performance data on site, you also need to define the optional streams for your site air and fuel so that the design calculations can be based on your site conditions. If these streams are not defined, the gas turbine solves using default ISO conditions. You can also specify the Exhaust Gas from design GT if you want the exhaust fluid conditions for the Design Case to be reported. Specs To model the losses and limits in the gas turbine, Petro-SIM allows you to specify the following variables on the Specs page for the Design case gas turbine. v 743 Chapter 8: General Unit Operations l l l l l Minimum VIGV angle ratio à Ratio of the minimum inlet guide vane angle to the maximum angle, when variable inlet guide vane angle settings are allowed. Used for single shaft gas turbines. Mechanical Power Efficiency à Efficiency of conversion of net turbine shaft work (Wnet) to electrical power. Comp Inlet Pressure Loss à Pressure loss in the air filter and other auxiliaries leading to the compressor. Given as a percentage of inlet air pressure or in normal pressure drop units. Turbine Outlet Pressure Loss à Pressure loss in the auxiliary equipment after the turbine. Given as a percentage of inlet air pressure or in normal pressure drop units. Combustor Pressure Loss à Pressure loss during the combustion process. Given as a percentage of compressor discharge pressure. You can also add User Variables and Notes. Rating The Gas Turbine Rating tab contains these pages: Specs You can specify one of the following variables on the Specs page to indicate the extent to which the gas turbine is utilized for the Actual or Rating Case: l l l l l l 744 v Power. This is the actual turbine power, referred to as W in Gas Turbine Theory. net Load wrt Design Power. This compares the actual GT Power with the Design Power specified on the Parameters page. Load wrt Inlet Conditions. For 100% load, the off design performance will be calculated for the gas turbine with respect to the current operating conditions of the actual air, fuel and injection/extraction streams. This full load at the current operating conditions will be the same as that specified on the Parameters page if the actual rating air is also at ISO conditions but will be if different if, say, the air inlet temperature is not 15°C or there are other differences in the inlet air or fuel stream. Turbine Inlet Temperature. This is the temperature at state 3 of the gas path. The turbine inlet temperature corresponding to 100% load is calculated by the object. You can specify a lower value if you want to set a part load duty without varying the inlet guide vane angle. LHV Duty. The LHV duty can be used to specify part load operation without varying the inlet guide vane angle. Fuel Flow. The Fuel flow rate can also be used to specify part load operation without varying the inlet guide vane angle. Gas Turbine By default, the gas turbine will be set to operate at 100% Load wrt Inlet Conditions. You can also specify the following Detailed Machine Specifications for the rating case: l l l l l Mechanical Power Efficiency. Comp Inlet Pressure Loss. Turbine Outlet Pressure Loss. Combustor Pressure Loss. Compressed Air Extraction. The design values for these parameters are specified on the Parameters page but Petro-SIM allows for differences in these values between the Design and Rating cases. This enables changes to the gas turbine after initial design specification, such as the addition of a downstream heat recovery steam generator, or a reduction in machine efficiency due to wear, to be modelled. If you enter a non-zero value for Compressed Air Extraction, you will have to specify a Compressed Air Stream on the Connections Page. Results You can see the following Design and Rating variables on the Results Page: l l l l Power Load wrt Design Power Load wrt Inlet Conditions Turbine Inlet Temperature v 745 Chapter 8: General Unit Operations l l l l l l l l l l l l l l l l l l LHV Duty Standard Wobbe Index Relative Wobbe Index, which compares the Wobbe Index of the current fuel with that of the Fuel that the unit was designed for. GT Exhaust Temp Specific Power Exhaust O2 vol dry Friction Heat Loss Combustion Temperature (Theoretical Flame Temperature) Gas Turbine Efficiency Heat Rate (1/Thermal Efficiency) Compressor Pressure Ratio Expander Pressure Ratio Comp Inlet Pressure Loss Turbine Outlet Pressure Loss Combustor Pressure Loss Compressed Air Extraction Minimum VIGV angle ratio Mechanical Power Efficiency Internals If you are using a Single Shaft Gas Turbine, you'll see the following variables: l 746 v Actual VIGV ratio. This will be a value between 1 and the minimum VIGV specified on the Parameters page, when the gas turbine is operating under part-load conditions. Gas Turbine l l l l l l l Compressor Outlet Temperature Compressor Isentropic Efficiency Compressor Polytropic Efficiency Expander Isentropic Efficiency Expander Polytropic Efficiency Total Air to Fuel Ratio Turbine Temperature Ratio, (T3/T4) If you are using a Twin Shaft Gas Turbine, you'll see the following variables: l l l l l l l l l l l l l Compressor Outlet Temperature Compressor Turbine Outlet Temperature Compressor Turbine Outlet Pressure Compressor Isentropic Efficiency Compressor Polytropic Efficiency Compressor Turbine Isentropic Efficiency Compressor Turbine Polytropic Efficiency Power Turbine Isentropic Efficiency Power Turbine Polytropic Efficiency Compressor Turbine Pressure Ratio Power Turbine Pressure Ratio Total Air to Fuel Ratio Turbine Temperature Ratio, (T3/T4) v 747 Chapter 8: General Unit Operations Refer to Control Options page for details on Single and Twin Shaft GTs. Control Options The Control Options page allows you to specify different or additional constraints that you want Petro-SIM to observe in solving the gas turbine. The options available depend on the shaft type for the gas turbine: Single Shaft GTs Upper End of GT Performance Group The parameters in this group are: l l Maximum Power. This limit comes into effect at low inlet air temperatures. Maximum IGV Setting Control Method for Part Load Operation These options apply when IGV modulation is used to reduce gas turbine load: l l Constant Turbine Inlet Temperature. The temperature value is calculated by PetroSIM but you can over-write this value especially when steam is injected into the gas turbine. Constant Exhaust Gas Temperature Control Method for High Ambient Temperatures In hot climates the IGV position of the gas turbine may be changed to avoid extreme changes in the air to fuel ratio. Petro-SIM does not calculate the IGV setting in such cases but these options can be used to determine the modified IGV setting 748 v Gas Turbine l l Maximum IGV Ratio. IGV Variation Slope. Negative slope expected as IGV will be at maximum value at the temperature boundary when these options come into effect. These options come into effect only when the inlet air temperature exceeds the value specified on this page. Twin Shaft GTs Upper End of GT Performance Group The parameters in this group are: l l Maximum Power. This limit comes into effect at low inlet air temperatures. Maximum Turbine Inlet Temperature for RatingThe temperature value is calculated by Petro-SIM but you can over-write this value especially when steam is injected into the gas turbine. v 749 Chapter 8: General Unit Operations Single Shaft and Twin Shaft Gas Turbines The gas turbine unit in Petro-SIM follows the process from point 1 to point 4, in one single unit operation, modelling the compressor, combustion reactor and turbine all together. Part of the turbine work developed is used to drive the compressor. The remaining turbine work, referred to as the GT power, is available to generate electricity, to propel a vehicle, or for other purposes. The exhaust gases are hot (300 à 600°C) and often serve as the heat source for the steam in steam power plants and industrial co-generation systems. The highest temperature in the cycle occurs at the end of the combustion process (state 3) and it is limited by the maximum temperature that the turbine blades can withstand. This is often termed the Turbine Inlet Temperature and it also limits the pressure ratios that can be used in the cycle. 750 v Gas Turbine The picture shown above represents a single shaft gas turbine in which one shaft connects the compressor, the turbine and the electricity generator. For a twin shaft gas turbine, one shaft connects the compressor and compressor turbine so the power generated in the compressor turbine is just enough to drive the compressor. A secondary turbine, or Power Turbine, then takes the fluid down to atmospheric pressure to produce the extra power which is turned into electricity or used for other purposes. With a twin shaft gas turbine, 6 main thermodynamic states exist. Gas Turbine Theory The ideal cycle that the working fluid undergoes in the gas turbine is known as Brayton cycle. Brayton cycle is made up of the following four internally reversible processes: l l l l 1-2: Isentropic compression (in a compressor) 2-3: Constant Pressure Heat addition 3-4: Isentropic expansion (in a turbine) 4-1: Constant pressure heat rejection When the compressor outlet pressure is known, the isentropic outlet temperature can be calculated : γ −1 γ −11 γ γ T P T1 P =  1  =  4  = 4 T4 T2 P 2 P 3 Heat transferred to and from the working fluid: Q in = H 3 − H 2 Q out = H 4 − H 1 v 751 Chapter 8: General Unit Operations W net Q in ηt = where P = Absolute Pressure T = Absolute Temperature H is the enthalpy of the fluid γ = ratio of specific heats W net = GT Power Q = Fuel LHV Duty in η th = Thermal Efficiency of the gas turbine Principal Irreversibilities and Losses The actual gas-turbine cycle differs from the ideal Brayton cycle because various losses occur so real processes are not isentropic. Some pressure drop occurs before the compression process, during the combustion process and after the expansion process. Also, the actual work input to the compressor will be more and the actual work output from the turbine will be less due to irreversibilities. The deviation from idealized isentropic behaviour can be accounted for by using the isentropic efficiencies of the turbine and the compressor. ηCi = ws / wa ≅ (H 1 − H 2s ) / (H 1 − H 2a ) ηTi = wa / ws ≅ (H 3 − H 4a ) / (H 3 − H 4s ) where w = Gross work input to the compressor or output from the turbine η =Isentropic efficiency of the compressor Ci η =Isentropic efficiency of the turbine Ti 2s, 4s: isentropic states 2a, 4a: actual states 752 v Gas Turbine Solution Method The widest comprehension of the general behaviour of all turbo machines is obtained from dimensional analysis1 . This is the formal procedure whereby the group of variables representing some physical situation is reduced to a smaller number of dimensional groups. Dimensional analysis makes it possible to predict the performance of one machine from the results of tests on a geometrically similar machine and also to predict the performance of the same machine under conditions different from the test conditions. For a fluid machine, geometrical similarity must apply to all significant parts of the system (that is, the rotor, the entrance, discharge passages, and so on). Machines which are geometrically similar form a homologous series. Therefore, the member of such a series, having a common shape are simply enlargements or reductions of each other. Following this principle of similarity, non-dimensional parameters are used to calculate the performance of rotating machinery. The most important non-dimensional parameter for predicting the behaviour of gas turbines is the Mach number2 , but other parameters such as the non-dimensional flow and non-dimensional speed are often used in place of the Mach number. Applying this principle, for the design case, Petro-SIM back-calculates the dimensional parameters of the gas turbine components (compressor, combustor, turbine) from the specified parameters (that is,Power Rating, Heat Rate, Pressure Ratio and Exhaust Temperature). These non-dimensional parameters are then used to determine the performance of the same gas turbine under different operating conditions. Consequently, Petro-SIM solves two operating cases in each gas turbine object: Design Case Here, easily obtained input parameters are used to calculate the design flow rates and efficiencies, which can later be used to model the gas turbine during off-design operation. The input parameters required by Petro-SIM are: l l l l Gas Turbine Base Load Rating at ISO (International Standards Association) conditions Heat Rate at Base Load Compressor Pressure Ratio Exhaust Temperature at Base Load These parameters can be obtained for most gas turbines from the Gas Turbine World Handbook, which is published annually. For the design case model, air is taken to be at ISO conditions of 1Fluid Mechanics, Thermodynamics of Turbomachinery; S.L. Dixon. 2Proceedings of the 29th TurboMachinery Symposium; Gas Turbine Performance – What Makes the Map, R Kurz and K. Brun. v 753 Chapter 8: General Unit Operations 15°C, 1 atm and 60% relative humidity while the fuel is taken to be pure Methane at 15°C by default. To base the design GT on a known performance on site, user defined air and fuel streams can be used instead of the internal ISO streams. For the design case, the following parameters are calculated . l l l l Turbine Inlet Temperature (TIT) at state 3. Compressor polytropic (and isentropic) efficiencies Expander polytropic (and isentropic) efficiencies Non-dimensional flow at states 1, 2, 3 and 4. The non-dimensional flow describes the axial Mach Number and is calculated from Stodola’s equation, Md = M T / P where M is the non-dimensional mass flow d M is the mass flowrate of the gas stream. T is the temperature of the fluid P is the pressure of the fluid The M parameter relates to the mass flow around nozzles and is derived from d PV = nRT l Flow in pipes ⇒ M = ρAV l Gas equation l Speed of sound γRT where P = Pressure V = Volume R = Gas constant T = Absolute Temperature ρ = Gas density A = Nozzle area γ = ratio of specific heats For design case calculations for the twin shaft gas turbine, the isentropic efficiencies are calculated for the compressor, compressor turbine and turbine. The non-dimensional flow parameter M is d also calculated for the six reference states. 754 v Gas Turbine Actual Case – Off Design Performance The performance of the gas turbine is dependent on a number of properties. Changes in any of the properties listed below will result in significant differences in the gas turbine performance. l l l l l Inlet Air Temperature Inlet Air Pressure, based on gas turbine altitude Inlet Air Humidity Fuel Composition etc. When the value of any of these parameters differs from the design values, the gas turbine is said to be operating Off Design. In solving the gas turbine for the off design operating case at full load, the turbine inlet temperature and M are used as the ‘handle’ or critical parameters. These values are kept d,3 constant while other properties in the gas turbine are re-calculated in-line with the changes in the performance-controlling parameters listed above. The calculation of the off-design performance of the engine involves an iterative procedure where several trials are carried out with the new set of input properties to ensure all engine variables are consistent with the critical parameters. During each of these iterations, the parameters that have to be checked for convergence include: l l l l l l l Air flowrate Fuel Flowrate Compressor Pressure Ratio Expander Pressure Ratio Compressor Efficiencies Expander Efficiencies etc. Part Load Operation Petro-SIM provides a number of specification variables to determine what percentage of the gas turbine’s capacity is to be utilized. The specifications indicate how the fuel flow is to be varied while Petro-SIM determines how the air is to be varied depending on the shaft type. Single Shaft Engines The behaviour of the gas turbine during part-load operation depends on the engine control path v 755 Chapter 8: General Unit Operations . For single shaft engines, two part-load control methods exist. These are: Constant Turbine Inlet Temperature Here, the gas turbine operates at constant TIT during full load while taking in the maximum amount of air that the gas turbine can handle at the current operating condition. When small load reduction is required, the machine first uses inlet guide vane modulation to reduce the air flow while maintaining a constant TIT. With inlet guide vane modulation, the exhaust gas temperature increases as load reduces. Inlet guide vane modulation continues to be used until the required load brings the inlet guide vane setting to the fully closed position (minimum angle). Below the minimum inlet guide vane point, the TIT must be reduced to achieve further load reduction2 . Constant Exhaust Gas Temperature When following the Exhaust Gas Temperature regime, the TIT and inlet guide vane settings are reduced together to maintain the exhaust gas temperature at a constant value3 . This constant EGT path is generally followed to avoid the risk of temperature shock in any subsequent steam turbine when the exhaust gas is used to raise steam for the steam turbine. Petro-SIM allows the user to specify the minimum variable inlet guide vane angle, as a fraction of the maximum angle. During part load operation, Petro-SIM follows the Constant Turbine Inlet Temperature path by default, but this control option can be changed so that the Constant Exhaust Gas Temperature path is followed instead. This maximizes the part load efficiency. For part load operation of single shaft engines, Petro-SIM first varies the inlet guide vane angle, while keeping the turbine inlet temperature at the maximum. Further reduction in load is then achieved by lowering the turbine inlet temperature This part load control results in the following profiles for Load against Exhaust Flow/Exhaust Temperature. 1Modeling Gas Turbine Engine Performance at Part-Load; P.T. Weber, D. Grace, Electric Power Research Institute, University of Wyoming. 2Refer to Proceedings of the 29th TurboMachinery Symposium; Gas Turbine Performance – What Makes the Map, R Kurz and K. Brun. AND Modeling Gas Turbine Engine Performance at Part-Load; P.T. Weber, D. Grace, Electric Power Research Institute, University of Wyoming. 3Modeling Gas Turbine Engine Performance at Part-Load; P.T. Weber, D. Grace, Electric Power Research Institute, University of Wyoming. 756 v Gas Turbine Twin Shaft Gas Turbines Twin shaft gas turbines are generally variable flow, variable speed engines so it is possible to reduce the air flow without the same limitation in single shaft gas turbines. Thus, Petro-SIM varies air flow and turbine inlet temperature as required to meet the specified load. v 757 Chapter 8: General Unit Operations All gas turbine modelling calculations in Petro-SIM are entirely thermodynamic in nature and do not take into account flow swirl, geometry, rigorous turbine cooling methodologies, or other advanced computational fluid dynamics. Steam Injection Petro-SIM allows for two optional steam or water streams to be injected into the gas turbine. 1. NOx injection steam can be injected into the combustor. Although this is normally used to reduce the amount of Nitrogen oxides formed during combustion, Petro-SIM does not calculate the effect in NOx formation, but merely models the effect on the theoretical flame temperature and the gas turbine power. So, the use of NOx steam injection will lead to an increase in GT Power and a reduction in the flame temperature. 2. A Power injection steam can also be injected into a twin shaft gas turbine between the compressor turbine and the power turbine. This has no effect on the firing temperature or NOx formation but does increase the GT power. Frequent use of steam injection increases the maintenance costs of the gas turbine so their use should be limited. Steam or water flow can be up to 5% of design air flowrate. When steam is injected, some gas turbines reduce the Turbine Inlet Temperature (TIT) that the engine is controlled at to protect the turbine blades. The reduction in TIT could be as much as 5°C for every 1% steam flow with respect to air flow. Petro-SIM does not apply this reduction in TIT automatically but provides options for changing the TIT at which the engine is controlled. Compressed Air Extraction Petro-SIM allows a proportion of the compressed air to be extracted before the balance is sent to the combustor. 758 v Gas Turbine Limits The Gas Turbine unit operation in Petro-SIM enables conceptual modelling of single and twin shaft gas turbines for power generation. The model predicts gas turbine behaviour to a high level of accuracy but it does have limits because it does not take effects like changes in Reynolds number and changes in clearances with temperatures into account. The typical operating Reynolds numbers of compressor blades and turbine blades are above the levels where the affect of changing Reynolds number is significant. Each gas turbine has its own specific limits of operation as defined by the manufacturer, which restrict speed and firing temperatures and these may not always be replicated by Petro-SIM. Some engines are limited in power output (especially at low ambient temperatures) for mechanical reasons: The engine shaft may be designed for maximum torque, which would be exceeded at low ambient temperatures if the engine were to be allowed to run at maximum firing temperatures13 . Petro-SIM solves and re-calculates the Turbine Inlet Temperature if the power limit is specified as a control option. In addition, each gas turbine may have additional mechanical limits that restrict actual speeds and firing temperatures, which are not explicitly addressed in Petro-SIM. These limits are achieved in practice by varying the TIT or by varying the inlet guide vane setting. Petro-SIM allows these values to be fixed by the user. 1Proceedings of the 29th TurboMachinery Symposium; Gas Turbine Performance – What Makes the Map, R Kurz and K. Brun. v 759 Chapter 8: General Unit Operations Burner The Burner unit operation is a general purpose combustion reactor used to model the combustion side of a Furnace, Boiler, or Supplementary Burner of a Heat Recovery Steam Generator (HRSG). For a Boiler or HRSG, the process side can be modelled in a separate Steam Generator unit using the product from the Burner as the hot Feed stream. Likewise, the process side of a Furnace can be modelled in a Heat Exchanger. The Burner accepts any number of feed streams and combines them before performing the combustion calculations. It detects the presence of combustible components in the feed mixture and for combustion, uses up as much oxygen as is required to ensure complete combustion. The easiest approach to defining the Burner is to fully specify the feed streams and let the product stream be calculated by the unit. The Burner solves for the flowrate of up to two feed streams if relevant output parameters such as burner duty, exhaust O composition, excess air or exhaust 2 temperature are specified. For more information, refer to Burner Combustion, Thermal Efficiency and Pressure Drop. 1. To add a Burner to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Burner (or click and drag it to the flowsheet). A Burner unit operation is added to the active flowsheet. 760 v Burner Burner in the PFD 3. In the Burner Property view, enter the properties in these tabs: l Design l Worksheet l Performance l Dynamics - This tab is available only in Dynamics mode. 4. To ignore the Burner during calculations, check Ignored. Design The Burner Design tab contains the following pages: Connections On the Connections page, specify the following: v 761 Chapter 8: General Unit Operations l l l l Name Product Stream Feed Streams Fluid Package Parameters On the Parameters page, specify the pressure drop across the burner. The inlet pressure to the burner is taken to be the lowest of the feed stream pressures. You can specify the pressure drop in absolute pressure units or as a percentage (%) loss relative to inlet pressure. Pressure drop is not calculated by the Burner unit but can be specified on this page. The Burner parameters are listed below: Parameters Description Burner Pressure Drop Difference between the Lowest Feed Pressure and Product Pressure Relative Pressure Drop Pressure Drop in the Burner as a percentage reduction of Inlet Pressure Specs The Specs page organizes the specification types and calculated flow rates into three groups. 762 v Burner Burner Specification The default scenario for the Burner to solve is one in which all the feed streams are fully specified so that all inlet flow rates are known. When this is the case, the last check box in the Burner Specification group is automatically checked and all other specifications must be deactivated. For other scenarios, where one or two stream flow rates are known, it is necessary to activate one of the specifications and provide a value that Petro-SIM should aim to achieve. The Firing LHV duty specification can only be activated when the fuel flow rate is unknown. Parameters Details Firing LHV Duty Burner combustion duty based on the Net Calorific Value. Excess Air Amount of air above stoichiometric rate required for combustion of the fuel. Exh O2 Dry percentage volume fraction of oxygen in the Burner product stream. Product Temperature Temperature of the product of combustion. Unknown Flowrates Petro-SIM lists the streams whose flow rates haven’t been specified but are to be calculated by the Burner in order to achieve the activated specificaitons. v 763 Chapter 8: General Unit Operations Heat Recovery Details Specify the heat absorbed from the product stream, after exiting the Burner. This is used to calculate the efficiency. Parameters Details Absorbed Duty Heat recovered from the burner’s product stream. Boiler/Furnace Efficiency The efficiency calculated assumes that the burner is the only heat source involved in providing the Absorbed Duty. This is normally true for the Boiler and Furnace but is not true for a gas turbine HRSG. Stack Temperature The product temperature, after recovering the Absorbed Duty, which is different from the temperature that the product stream leaves the burner. You can also add User Variables and Notes. Performance The Performance tab summarizes the results of the Burner’s performance on the Summary page. Petro-SIM calculates the following parameters: l l l 764 v Firing LHV Duty Excess Air Exhaust O2 Burner l l l l l l Product Temperature Absorbed Duty Boiler/Furnace Efficiency Stack Temperature Sulphuric Acid Dew Point (Lower) Sulphuric Acid Dew Point (Higher) Burner Combustion, Thermal Efficiency and Pressure Drop Combustion The Burner will carry out combustion calculations for any gas or liquid fuel in the presence of air without the need to provide the reaction equations. It automatically derives the combustion equation for each component in the feed and assumes 100% combustion in determining the products of combustion. When a hydrocarbon burns in oxygen, the reaction will only yield carbon dioxide and water. When elements are burned, the products are primarily the most common oxides. Carbon will yield carbon dioxide, nitrogen will yield nitrogen dioxide, sulfur will yield sulfur dioxide. This general expression1 for combustion of a hydrocarbon fuel applies: Cm H n + ( m n )O = mCO + ( n )H O 4 + 4 2 2 2 2 Thermal Efficiency of the Burner The efficiency calculated by the Burner is only applicable when modelling a fresh air Boiler or Furnace. This is because the Burner does not take into account other heat sources like in gas turbine combustion. The Furnace or Boiler efficiency depends on the heat recovered after the combustion activity in the Burner itself. 1Perry, R.H. and D.W. Green. Perry’s Chemical Engineers’ Handbook (Sixth Edition) McGraw-Hill (1997) p. 9-38 . v 765 Chapter 8: General Unit Operations The efficiency will be calculated when either the absorbed duty or final product temperature after heat recovery from the burner product is specified. η= QA bs Q BN Where: Q Abs = Absorbed duty, which for a boiler will be the steam generation duty, Q SGEN Pressure Drop Pressure drop is not calculated by the Burner unit but can be specified on the Design, Parameters page. 766 v Steam Generator Steam Generator The Steam Generator unit operation performs design and UA rating calculations for a steam generator with a steam drum and water blowdown. Its basic function is to cool hot gases while generating steam. It is a multi-purpose steam generator that can be used to model a conventional Steam Boiler or a Heat Recovery Steam Generator (HRSG). It becomes an HRSG when the heat source is the exhaust stream from a Gas Turbine unit (or CO-rich stream from FCC unit or any other hot waste heat stream). It becomes a Boiler when the heat source is the product of combustion in a separate burner, in the presence of fresh air. 1. To add a Steam Generator to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Steam Generator (or click and drag it to the flowsheet). A Steam Generator unit operation is added to the active flowsheet. Steam Generator in PFD v 767 Chapter 8: General Unit Operations 3. In the Steam Generator property view, enter the parameters in these tabs: l Design l Rating l Worksheet l Performance 4. To ignore the Steam Generator during calculations, check Ignored. The Steam Generator unit operation can be used to model any of the three different types of steam generators: l l l Natural Circulation Steam Generator (NCSG). The gas typically flows horizontally across vertical tubes. Forced Circulation Steam Generator (FCSG). Gas typically flows vertically across horizontal tubes. Once Through Steam Generator (OTSG) While OTSGs can be solved in Design mode as a simple heat exchanger using the Weighted Design model, NCSGs and FCSGs need a dedicated steam generation unit to handle the complexity of having a steam drum. The essential characteristic of NCSGs and FCSGs is the separation of the successive tasks necessary to produce superheated steam: l l l l The heating of liquid water is done in a heat exchanger called the economiser. Vaporization of the preheated water is done in a heat exchanger called the evaporator or boiler. Superheating of the vaporized steam is done in a superheater. The steam drum separates the liquid phase from the steam. A single pressure Steam Generator is represented below. 768 v Steam Generator Refer also to these additional reference topics: l l l Economiser Multiple Steam Pressures Steam Generator Theory Design The Steam Generator Design tab contains these pages: Connections Use the Connections page to link streams to the unit operation: v 769 Chapter 8: General Unit Operations l l l l l l l l l l Unit Op Name. Number of steam levels. Type of arrangement, if more than one level. On/Off Status allows you to switch the steam generator off. When off, the steam and blowdown streams will be solved with zero flows while the hot outlet is solved with same condition as the hot inlet. Hot stream inlet to the unit for the design case. This is used, alongside the design parameters and specifications, to calculate the UA size for the exchangers in the unit. Hot stream inlet to the unit for the rating case. Hot stream outlet from the unit. This is used for the rating case. The hot product stream for the design case is not returned as output but the outlet temperature is returned on the Performance tab. Boiler Feed Water stream as inlet to the unit. This is used for the rating case only. Boiler Feed Water parameters for the design are to be specified on the Design, Parameters page. Steam stream as outlet from the unit; one for each level. For the rating case only. Blowdown stream as outlet from the unit; one for each level. For the rating case only. Parameters Specify the unit operation properties required for the steam generation to solve in design mode on the Parameters page. 770 v Steam Generator Optionally, de-select the Show Steam Side Pressure Drops check box to show fewer parameters. Parameters Description Hot Delta P This is the pressure drop experienced on the hot side, over the entire steam generation duty. Radiant Heat Loss The heat loss in the radiant section of the steam generator. When a value greater than zero is specified, the hot stream inlet temperature to the highest level superheater will be lower. This will apply when the steam generator is modelling a boiler. Required Steam Parameters for Design Mode For each steam level, specify the following: Parameters Description Steam Pressure This is the steam pressure that the HRSG was or is to be designed for. Steam Temperature The superheat temperature for the steam level. You can specify this directly or it can be calculated from a given superheat Delta T. Superheat ΔT Difference between steam saturation temperature and superheat temperature. Either specify this or the superheat temperature. Economiser Approach ΔT This is the temperature difference between the cold outlet temperature of the economiser and the steam saturation temperature. It is required to be greater than zero to ensure there is no steam vapourization in the economiser. For an OTSG, a nominal value of 0.01°C is required. Blowdown rate The amount of water blown out of the steam drum, represented as a percentage of steam flow from the same level by default. So, for a single level steam generator with 10% blowdown rate of 1kg/s, the steam flow will be 10 kg/s and the boiler feed water flowrate will be 11kg/s. Economiser DP The pressure drop in the economiser, which is the BFW preheat exchanger. Evaporator DP The pressure drop between the economiser exit state and the evaporator exit state. Superheater DP The pressure drop in the superheater. v 771 Chapter 8: General Unit Operations Required Boiler Feed Water Parameters for Design Mode Parameters Description BFW Pressure Pressure of the Boiler Feed Water stream used in designing the HRSG. BFW Temperature Temperature of the Boiler Feed Water stream used in designing the HRSG. Specs The Specs page has three groups that organize the various specification and solver information: Tolerances and Boundary Values These are required for the steam generator solve process. 772 v Parameters Details UA Tolerance For rating models, the steam flowrates can be adjusted until specified UA values have been met. The UA tolerance is the convergence criteria used to determine if the calculated UA value is sufficiently close to the specified value. Maximum Number of The steam generator carries out a number of iterative calculations, in the design mode and the rating mode. The calculations will continue until a solution is found Steam Generator Parameters Details Iterations or the iteration limit is reached. You can vary this number to limit the effort given in search of a feasible solution. Minimum Economiser ΔT Approach When the economiser UA is specified, the approach ΔT will be calculated by Petro-SIM. When there is the risk of steam vapourization in the economiser, possibly because the gas turbine is operating at a load lower than 60% and the economiser is over-sized, Petro-SIM will calculate a suitable blowdown fraction to ensure the economiser approach ΔT is equal to the minimum value set here. Specifications for the Design Mode Four sets of specification variables can be used to define your steam generator. They are: Parameters Description Mass Flowrate For each steam level: l Pinch ΔTmin For each steam level: l Total Duty The results for the steam generator will be determined by fixing the steam flowrate at the specified value. This is the quickest specification route. The minimum temperature difference between the hot stream and water/steam. This is the most typical specification variable. The steam flowrate will be adjusted until the specified ΔTmin is achieved within a small tolerance. For each steam level: l This is the sum of the heat transferred in the economiser, evaporator and superheater at each steam level. The required steam flowrate to achieve the specified duty will be calculated. Hot Outlet Temperature When this is specified, Petro-SIM will vary the ΔTmin and steam flowrate until the specified temperature is achieved, within a small tolerance. For multi-level steam generators, the same ΔTmin will be used for all the levels. No Design calcs Use this specification if the UA values are already known so that no design calculations are necessary. Specifications to determine Steam Generator Efficiency The efficiency of the steam generator is dependent on where the heat in the hot inlet gas is derived from. You can indicate the heat source by specifying the following parameters: v 773 Chapter 8: General Unit Operations Parameter Description Gas Turbine Power, W GT Gas Turbine LHV Duty, Q GT Upstream Burner Duty, Q BN The net power of an upstream gas turbine, when the steam generator is modelling a gas turbine HRSG. If the gas turbine power is specified, the combustion LHV duty should also be specified here. For boilers, this will be the boiler duty. For HRSGs, this will be the duty of the supplementary burner. If GT power is specified, the burner duty will be taken to be the HRSG supplementary firing duty. You can also add User Variables and Notes. Rating Having solved the steam generator in design mode, you may want to access its performance under different conditions. For instance, you may want to see its performance when the gas turbine or boiler is running at partial load. You may also want to consider supplementary firing of the gas turbine exhaust and review its effect on steam generation. The Rating tab allows you to provide additional parameters and specifications for such rating evaluations on these pages. Parameters On the Parameters page, you can specify the fixed properties required for the steam generation to solve in rating mode. 774 v Steam Generator Optionally, de-select the Show Steam Side Pressure Drops check box to show fewer parameters. Parameters Description HP Desuperheater Temperature When the hot feed for the rating case is supplementarily fired gas turbine exhaust, the steam temperature from the superheater in the rating case will be hotter than that in the design case where no supplementary firing was involved. For the HP steam, this temperature may be higher than the material limit. Petro-SIM will desuperheat the steam to the temperature limit supplied here, using saturated water from the HP steam drum. This temperature defaults to HP steam temperature in the design case but can be overwritten. You can specify a very a high temperature if desuperheating is not required. Hot Delta P This is the pressure drop experienced on the hot side, over the entire steam generation duty for the rating case. Required Steam Parameters for Rating Mode For each steam level. specify the following Parameters Description Steam Pressure This is the steam pressure for the rating case. Blowdown rate The amount of water blown out of the steam drum, represented as a percentage of steam flow from the same level by default. So, for a single level steam generator with 10% blowdown rate of 1kg/s, the steam flow will be 10kg/s and the boiler feed water flowrate will be 11kg/s. Economiser DP The pressure drop in the economiser, which is the BFW preheat exchanger. Evaporator DP The pressure drop between the economiser exit state and the evaporator exit state. Superheater DP The pressure drop in the superheater. Specs The sizing parameters used by the steam generator are the UA values for each exchanger section in the steam generator. In Design mode, the UA values are calculated by Petro-SIM and they will be transferred to the rating mode automatically after the design mode calculation has completed. You can also specify the UA values manually if they have been determined by some other means. The UA values for the economiser, evaporator and superheater should be specified at the same time and for every steam level in the generator. v 775 Chapter 8: General Unit Operations Specs for Rating Mode For each steam level, specify the following: Parameters Description Economiser UA Product of heat transfer area and overall heat transfer coefficient in the economiser. When the economiser UA is specified, the Approach ΔT parameter on the design tab should be unknown. Evaporator UA Product of heat transfer area and overall heat transfer coefficient in the evaporator. When the evaporator UA is specified, the steam flowrate, total level duty and hot product temperature, should be unknown. Superheater UA Product of heat transfer area and overall heat transfer coefficient in the superheater. When this is specified, the steam temperature should be unknown. Optional Specifications to determine Steam Generator Efficiency Similar to the design case, you can also specify these values for the rating case to allow the efficiency to be calculated: l l l 776 v Gas Turbine Power, W GT Gas Turbine LHV Duty, Q GT Upstream Burner Duty, Q BN Steam Generator Performance The Performance tab has pages that display the results of the Steam Generator’s overall performance including plots and tables. There are two sets for all the results reported on the Performance tab; one for the Design case and one for the Rating case. On each page, check Design or Rating radio button to indicate which set of results you want to view. Results Overall Steam Generator Results The Overall Results group contains the following parameters that are calculated by PetroSIM: Parameter Description Boiler Feed Water Flow Total BFW sent to the steam generator. This will equal the total steam flow to all steam levels and blowdown flow from all steam levels. Desuperheating Water This is the flow of HP saturated water used to de-superheat the HP steam. This water is included in the HP steam flow. Steam Generation Duty Total heat transferred in the steam generator. This equals the sum of all heat transferred in the economiser, evaporator and superheater of all steam levels. v 777 Chapter 8: General Unit Operations Parameter Description Hot TOut Temperature of the hot product stream. Overall Efficiency The highest of stand-alone, HRSG and boiler efficiencies determined for the unit. Level-Specific Results The Level-Specific Results group contains the following parameters that characterize each steam level. Most of these are calculated by steam generator object but some are specified for the stream or the unit. Parameter Description Pressure Pressure for the current steam level. Temperature Steam temperature, including superheat. Saturation Temperature Steam temperature without superheat. Mass Flowrate Amount of steam generated at the current level. Pinch ΔTmin The minimum temperature difference between the hot stream and the water/steam. Economiser Approach ΔT This is the temperature difference between the cold outlet temperature of the economiser and the steam saturation temperature. It is required to be greater than zero to ensure there is no steam vaporization in the economiser. Economiser UA Product of heat transfer area and overall heat transfer coefficient in the economiser. When the economiser UA is specified, the Approach ΔT parameter on the design tab should be unknown. Evaporator UA Product of heat transfer area and overall heat transfer coefficient in the evaporator. When the evaporator UA is specified, the steam flowrate, total level duty and hot product temperature, should be unknown. Superheater UA Product of heat transfer area and overall heat transfer coefficient in the superheater. When this is specified, the steam temperature should be unknown. Total Duty This is the sum of the heat transferred in the economiser, evaporator and superheater at each steam level. The required steam flowrate to achieve the specified duty will be calculated. Economiser Duty Heat transferred from the hot stream to the economiser in the current steam level. Evaporator Duty Heat transferred from the hot stream to the evaporator in the current steam level. Superheater Duty Heat transferred from the hot stream to the superheater in the current steam level. 778 v Steam Generator Detailed Results The Detailed Level-Specific Results group reports the various blowdown fraction types and the hot stream outlet temperatures from each exchanger section: Parameter Description Blowdown Rate (Steam) Percent equivalence of blowdown flowrate divided by steam flowrate from level. Blowdown Rate (Level BFW) Percent equivalence of blowdown flowrate divided by boiler feed water flowrate to level. Blowdown Rate (Total BFW) Percent equivalence of blowdown flowrate divided by total boiler feed water flowrate to the steam generator. Steam Rate (Total BFW) Percent equivalence of steam flowrate divided by total boiler feed water flowrate to the steam generator. THOut from economiser Hot outlet temperature from the economiser. This is also the hot inlet temperature to the next lower pressure level or the final hot product temperature after the lowest level pressure level. THOut from evaporator Hot outlet temperature from the evaporator. This is also the hot inlet temperature to the economiser. v 779 Chapter 8: General Unit Operations Parameter Description THOut from superheater Hot outlet temperature from the superheater. This is also the hot inlet temperature to the evaporator. Superheat ΔT Difference between the steam outlet temperature and its saturation temperature. Efficiencies The efficiency of the steam generator depends largely on the process by which the heat transferred in the steam generator was put into the hot stream prior to it being used in the steam generator. The steam generator unit allows the heat input to the hot stream before this unit to be specified so that the relevant efficiencies can be determined for the steam generator. Steam Generator Efficiencies 780 v Parameter Description Steam Generation Duty, Q SGEN Heat Loss down to 15°C, Q Loss Total heat transferred in the steam generator. Difference in hot stream heat flow between the outlet temperature from the generator and 15°C as a reference ambient condition. This is used to determine the stand-alone efficiency. Steam Generator Parameter Description Stand-Alone Efficiency, This efficiency, which uses the hot stream duty to ambient temperature as the reference, is used to rate the steam generator when the burner and gas turbine duties are not known. η HOT Gas Turbine Power, W GT The net power of an upstream gas turbine, when the steam generator is modelling a gas turbine HRSG. Gas Turbine LHV Duty, Q GT Upstream Burner Duty, Q BN HRSG Efficiency, η HRSG If the gas turbine power is specified, the combustion LHV duty should also be specified here. Boiler Efficiency, The boiler efficiency will only be reported if the upstream burner duty has been specified and GT power is unknown. η Blr Oxygen in exhaust For boilers, this will be the boiler duty. For HRSGs, this will be the duty of the supplementary burner. This is the efficiency when the steam generator is to model an HRSG. The burner duty and the GT LHV duty become the heat input and the GT power and the steam generator duty become the heat output. Dry percentage volume fraction of oxygen in the hot product stream. Sulphuric Acid Dew Point The upper and lower acid dew point temperatures are reported. The dew points will only apply if the composition of SO in the hot inlet stream is greater than 0 . 2 The following results are reported. l l l Hot Exhaust Temperature Lower Sulphuric Acid Dew Point Higher Sulphuric Acid Dew Point Plot The Plot page displays the composite curves for the steam generator. This is a plot of the heat flow (on the x-axis) against the temperature (on the y-axis).You can show the design composites and the rating composites together. If the steam generator is modelling an HRSG and the gas turbine is running part-load, the rating case involves less heat transfer than the design case as shown. When the rating case involves supplementary firing, it involves more heat transfer than the design case. v 781 Chapter 8: General Unit Operations You can modify the display of the plot using the Graph Control view. Plot Data On the Plot Data page, you can view the data used to plot the composite curves on the Plot page in a table. 782 v Steam Generator Messages The Messages page contains a list of the warning messages on the Steam Generator. You cannot add comments to the page, but you can check if there are any warnings in modelling the Steam Generator. Economiser The economiser enables more heat to be recovered from the hot stream to preheat the boiler feed water before the hot stream goes to stack. It is important to prevent steam from forming prematurely, in the economiser. For this reason, the water preheat temperature is lower than the saturation temperature. The difference between the economiser exit temperature and the saturation temperature is termed the approach temperature. For modern designs this can be as low as 1°C for HRSGs, but is typically about 10°C. Conventional steam boilers and other boilers with high hot inlet temperature tend to require higher approach temperatures. This is different from the pinch temperature difference, which is the gap between the hot cooling profile and the cold heating profile. The temperature-enthalpy profile below illustrates the 2 delta temperatures. v 783 Chapter 8: General Unit Operations With OTSGs, there is no steam drum so the unit can be solved as one single exchanger. To model an OTSG using the Steam Generator unit operation, the ΔTApproach should be set to a nominal amount of 0.01°C and the blowdown rate should be set to 0. Multiple Steam Pressures Multiple pressure levels are sometimes used to increase the amount of heat recovered from the hot stream, which increases the overall steam generation efficiency. This is because recovering to steam at a lower saturation temperature reduces the stack temperature. The Steam Generator in Petro-SIM will solve for up to three steam levels: l l l High Pressure (HP) Intermediate or Medium Pressure (IP or MP) Low Pressure (LP). Each level has a separate steam stream and a blowdown stream. With multiple levels, there are three different arrangement types: Cascade Arrangement In this arrangement, the LP economiser preheats the entire boiler feed water used in the system. After separating the blowdown and steam flows for the LP level, the remaining water from the LP drum is then pressurized and preheated in the IP economiser. BFW to the HP level is then removed from the IP drum. The corresponding network structure is optimized from the Pinch Technology point of view. The heat recovery journey of the streams in a triple level cascade system is shown below. 784 v Steam Generator Parallel Arrangement Here, the total boiler feed water is split into the number of steam levels at the onset. The LP economiser therefore preheats just enough water to provide the steam and blowdown flow for the LP level and likewise for the IP and HP economisers. The consequence is that the inlet temperature to the IP and HP economisers are the same as that of the LP economiser. If the IP economiser is located immediately after the LP economizer for heat recovery, the heat exchange network becomes non-optimal. This arrangement can be optimized by splitting the IP and HP economisers into two or more parts and matching the streams against the hot stream in a parallel arrangement. When there is little or no superheating at the lower pressure levels, this parallel arrangement leads to an enthalpy profile equal to the cascade arrangement. The composite curves below illustrate this. In the parallel arrangement, the LP economizer section will have 3 parallel exchangers, one for each level. The cascade arrangement will only have one heat exchanger and the flow to the other levels are taken after the economiser. In the parallel arrangement, the LP superheater and IP superheater can also be located at the hotter end where appropriate to improve the use of driving forces. When the degree of superheat is small, as often is the case, this is not so beneficial, hence the enthalpy profile for the parallel arrangement becomes equivalent to that of the cascade arrangement. v 785 Chapter 8: General Unit Operations In such cases, the cascade arrangement can be used for conceptual analysis without significant loss of accuracy. When there is significant superheating at the lower steam pressures, there are several potential network structures for the parallel arrangement which cannot be combined into one unit in Petro-SIM. Such complex arrangements will need to be modelled by combining the heat exchanger objects to form the steam generator network. Serial Arrangement In this scenario, the Steam Generator models the basic Parallel arrangement, with just one economiser for each level. This is a Serial arrangement in Petro-SIM because the exchangers on the steam side are arranged in a serial sequence as shown below. The hot gas first transfers heat to the superheater, evaporator and economiser of the HP steam before transferring heat to the IP and LP levels. 786 v Steam Generator For Dual Pressure and Triple Pressure generators, you can choose between the Cascade arrangement and the Serial arrangement for the heat recovery network. Each level will also be built as 3 separate heat exchangers (economiser, evaporator and superheater) with a steam drum. A triple pressure cascade Steam Generator is illustrated below. v 787 Chapter 8: General Unit Operations Steam Generator Theory The Steam Generator calculations are based on energy balances for the hot and cold fluids. In the general relations, the hot fluid supplies the heat required by the economiser, evaporator and superheater on the water/steam side. For a single level steam generator: ( ) ( ) M hot(H in − H out)hot = M steam H out.stm − H in.BFW + M bd H out.bd − H in.BFW where: M = fluid mass flow rate H = enthalpy The subscripts hot = hot (gas) side BFW = boiler feed water stream 788 v Steam Generator bd = blowdown stream stm = steam stream in = inlet out = outlet The presence of the steam drum makes it necessary to divide the steam generator into three separate intervals, one for each heat exchanger, as shown below. This is equivalent to using the Weighted Exchanger Design Model, where heat transfer is calculated for each interval, then summed to determine the overall transfer. The heat transferred within the exchangers can be determined from the following equations: Q econ = M hotCp hot(T H 3,4 − T H 5) Q econ = (M stm + M bd )Cp BFW(TC 4 − TC 5) ( ) Q evap = M hotCp hot T H 2 − T H 3,4 ( ) Q evap = M stm H C 2 − H C 3 ( ) Q sup = M stmCpstm(TC 1 − TC 2) Q sup = M hotCp hot T H 1 − T H 2 M bd = M stmx bd TC 2 = TC 3 + ∆Tmin T H 3,4 = TC 3 + ∆Tmin v 789 Chapter 8: General Unit Operations where: Cp= average mass specific heat capacity The subscripts x= mass fraction econ = economiser evap = evaporator sup = superheater stm = steam stream in = inlet out = outlet Design Calculations For design calculations the steam pressure and temperatures are known, but there are nine unknown parameters which are: T H2 ,T H3,4 ,T H,5 ,T C4 ,Q econ ,Q evap ,Q sup ,M ,M stm bd . For design calculations, the steam flow rate can be determined by solving the last two heat transfer equations. Rating Calculations The heat transferred between the gas (hot) and steam sides can also be defined in terms of the overall heat transfer coefficient, the area available for heat exchange and the log mean temperature difference: Q = UA ∆T LM where: U = overall heat transfer coefficient A = surface area available for heat transfer ΔT LM = log mean temperature difference (LMTD) The heat transfer coefficient and the surface area are often combined for convenience into a single variable referred to as UA. So, Q econ = UA econ∆T LM 4,5 Q evap = UA evap∆T LM 1,2 790 v Steam Generator Q sup = UA sup∆T LM1,2 For rating calculations the steam pressure and UA values are known, but there are ten unknown parameters which are: T H2 ,T H3,4 ,T H,5 ,T C1 ,T C4 ,Q econ ,Q evap ,Q sup ,M ,M stm bd . Combining the first seven heat transfer equations with the heat transfer coefficients equations gives ten equations that are needed to solve for the ten unknown parameters. Solution Routes Two main routes can be followed in solving these equations: l l Simultaneous Route, where a global method based on a matrix formation is used to solve the system. Sequential Route, where a number of guesses and checks are used to solve the problem. The sequential approach is thought to be better for this kind of problem, especially when considering the number of equations in a multi-pressure system1 . Thermal Efficiency of the Steam Generator As the Steam Generator may be used to model a conventional Steam Boiler or a Heat Recovery Steam Generator, its efficiency depends on the origin of the hot inlet stream. 1ASME Cogen – Turbo ’94. Part-load operation of combined cycle plants with and without supplementary firing. P.J. Dechamps, N. Pirard, Ph. Mathieu. v 791 Chapter 8: General Unit Operations The efficiency is determined as 792 v Steam Generator η= Useful Heat Output Heat Input If the gas turbine power is specified, with or without a supplementary firing duty, the HRSG efficiency can be determined as: ηHRSG = Q SGEN + WGT Q Gt + Q BN If only a burner duty is specified, the Boiler efficiency will be determined from: ηBlr = Q SGEN Q BN If neither the gas turbine power/duty nor the burner duty is specified, the stand-alone steam generator efficiency can be determined as the effectiveness of heat removal from the hot stream. Thus: η Hot = Q SGEN Q Hot The relevant heat in the hot stream is determined as: Q Hot = Q Rad + Q SGEN +Q Loss where: Q Rad = Radiant heat loss Q = Heat duty required to cool the hot from the temperature it exists the steam Loss generator, down to 15°C. Acid Dew Point When the fuel burnt in the gas turbine or burner contains sulfur or hydrogen sulphide, sulfur dioxide (SO ) will be formed during the combustion process. Some of the SO (1 – 5%)6 forms 2 2 Sulphur trioxide, which combines in water to form Sulphuric Acid. This initiates corrosion in the HRSG when the metal temperature falls below the acid dew point. To prevent this corrosion, the acid dew point should be monitored to ensure heat recovery does not cool the gas beyond the acid dew point. Sulphuric acid dew point is calculated from this equation6 . 1000 / T A dp = 2.767 − 0.0294*lnP H 2O − 0.0858*lnP H 2SO 4 + 0.0062 * lnP H 2O * lnP H 2SO 4 v 793 Chapter 8: General Unit Operations where: P = Partial Pressure in mmHg T = Temperature in K subscripts: A dp = acid dew point Pressure Drop Pressure drop is not calculated by the Steam Generator unit but can be specified by the user in the Design, Parameters page. Petro-SIM does not use these values to perform a pressure balance on the system and does not calculate the pumping power required to raise the boiler feed water to the required pressure. The effect of supplying the pressure drop values is that the pressure differences are taken into account when calculating the enthalpy values at different points. 794 v Steam Jet Ejector Steam Jet Ejector Ejectors are flow induction devices for liquid and gas transport. They use a motive fluid (also called driver or primary fluid) to flow at high velocity through a shaped nozzle, producing—in most cases of gas flow—a supersonic jet. This jet enters a mixing chamber, where it pulls in (entrains) the suction fluid, also called secondary or process fluid. The mixture then flows through the diffuser throat, where mixing should be completed and finally through the diverging diffuser, where its velocity is transformed into static head and from where it is discharged at a pressure somewhere in between the suction and the motive pressure. Petro-SIM currently only handles steam ejectors; only steam can be taken as the motive fluid. For more information, refer to About Steam Jet Ejectors. 1. To add a Steam Jet Ejector to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Steam Ejector(or click and drag it to the flowsheet). A Steam Jet Ejector unit operation is added to the active flowsheet. 3. In the Steam Jet Ejector property view, enter or view the properties in these tabs: l Design l Worksheet l Performance 4. To ignore the Steam Jet Ejector during calculations, check Ignored. v 795 Chapter 8: General Unit Operations Design The Steam Ejector Design tab contains these pages Connections Page Specify the inlet (motive and suction) and outlet (discharge) streams on the Connections page. Optionally, change the name of the operation in the Name field. Parameters The Parameters page allows input of ejector design parameters and/or data for some wellestablished operating reference point. We recommend that you specify as many parameters as possible. 796 v Steam Jet Ejector Parameter Description Motive Nozzle Throat Diameter (A) This is the diameter at the narrowest point of the motive steam inlet nozzle. Specifying it, along with the motive and suction pressures, will allow simultaneous calculation of the motive and suction mass flows. OPTIONAL Diffuser Throat Diameter (B) This is the diameter at the narrowest point of the diffuser - normally the point just before the diffuser starts to diverge. OPTIONAL Reference Operating Point It is recommended that you specify design data for these Pressures, Temperatures and Mass Flows, to help Petro-SIM derive certain performance characteristics, which can then be applied to other operating conditions, provided they are within a certain “envelope” around this reference point. When the reference point is incomplete, the model effectively estimates the design-point performance for a generic ejector. When the reference point is complete, the model switches to a "rating" mode. The minimal data required for a useable reference point are the two flow rates and three pressures. The motive steam temperature and motive nozzle diameter complete the reference point. The Diffuser throat diameter is only used to let the model estimate a discharge coefficient for the Diffuser as a result by itself. This assumes that the current discharge composition is roughly the same as in design conditions. v 797 Chapter 8: General Unit Operations As an example of the difference between rating and design mode, consider an increase in motive pressure with all else remaining constant. In design mode, i.e. without a reference operating point, the model will calculate a higher suction flow (Entrainment Ratio), as it assumes the ejector will be sized specifically for that higher expansion ratio. In full rating mode, however, if the motive pressure goes above its design pressure, the suction flow will gradually decrease, as the sizing of the ejector is assumed to stay fixed. You can also add User Variables and Notes. Performance Use the Performance tab to view the key calculation results for the ejector performance. Refer also to Calculation Methodology. 798 v Results Description Motive nozzle discharge coefficient Discharge coefficient for flow through orifice. If sufficient design parameter data were provided, then this value is derived. Otherwise, it is set to a default value of 0.95, which is fairly standard for shaped (DeLaval) nozzles. Expansion ratio (R_ exp) This is the current ratio of motive pressure to suction pressure. A minimum ratio is also provided, above which the flow through the motive nozzle will stay choked. Suction pressure lift This is the pressure increase from suction conditions to discharge conditions. Diffuser throat discharge coeff. See Motive nozzle discharge coefficient. Diffuser efficiency Thermodynamic efficiency of the diffuser. Steam Jet Ejector Results Description Compression ratio (R_ This is the current ratio of discharge pressure to suction pressure. A comp) minimum ratio is also provided, above which the ejector achieves sonic boost. Equivalent air mass load A standard way of handling suction flows, used in calculations, but also in the load curves that are normally part of supplier's design documents. Calculated at 70°F, following HEI Standards. Equiv. water vapour load A standard way of handling suction flows, used in the load curves that are normally part of supplier's design documents. Calculated at 70°F, following HEI Standards. Entrainment ratio Ratio of suction mass flow per motive mass flow. Overall efficiency An efficiency that takes into account both thermodynamic and fluid-flow (entrainment) performance. Calculation Methodology Petro-SIM follows the standard procedure from the Heat Exchanger Institute (HEI) Standards, for converting the suction mass flow into an equivalent dry-air mass load and water vapour mass load, both at 70°F and both reported among the results. These are used internally for calculation purposes, but also allow comparison of results with certain design specifications (e.g., load curves). Depending on the data available, Petro-SIM's calculation method can derive: l l l l Motive steam flow rate Suction fluid flow rate Suction pressure Discharge pressure If motive and suction pressure are specified and the nozzle-throat diameter is also provided, then both the motive and suction flow rates,and therefore the discharge mass flow, can be derived simultaneously. See also Relief Valve Theory. It is recommended that you provide a reference design (or operating) point, to aid with calibration of the calculations. The Diffuser Throat diameter is an entirely optional entry and currently only serves to produce the Diffuser Throat discharge coefficient as a side result that can be used to judge possible problems with the ejector. You will receive warnings if the expansion ratio or the compression ratio exceed their realistic limits, but also if any of the three pressures involved lie too far from the reference point provided. v 799 Chapter 8: General Unit Operations Efficiency Some portion of the energy in the motive fluid is used to compress suction fluid to final conditions while the remainder is exhausted as heat in the discharge stream. Thus, for most ejector applications, the efficiency relates to the fraction of motive energy that is successfully used to compress the suction fluid. In good designs, the diffuser efficiency is by far the largest contributor to this and it is therefore reported among the results. Various formulations are proposed in literature for the overall efficiency of ejectors. Petro-SIM uses a definition presented by Croll-Reynolds Corp., which also takes into account the amount of suction fluid entrained. About Steam Ejectors In the process industry, ejectors are used mainly to generate vacuum on the suction side, but also to enhance drying of some material on the suction side. Steam ejectors are so called, because they use steam as the motive fluid. Thermo-compressors are a special case of steam ejectors, where both the motive and the suction fluid are steam and the ejector is used to produce an intermediate steam quality in the discharge; a way to upgrade the lower-value suction steam. Every ejector is very specifically laid out for its design duty. It has no moving parts and relies entirely on the correct dimensions of the motive nozzle, the mixing chamber and the diffuser, which rigidly fix its performance characteristics. The absence of moving parts means it has lower capital and maintenance cost, but also causes the main drawback of jet ejectors: they are designed to work in a relatively narrow operating region and their performance rapidly deteriorates when moving away from the optimum point. The most common operational problem is called breaking which is caused by a deviation in discharge pressure. This causes the ejector to exit its desired critical operation and lose its sonic boost. The sonic boost is the large pressure increase gained from the shock wave in the diffuser throat, when the mixed fluid drops from supersonic to sonic velocity. Public domain sources offer various short-cut methodologies for preliminary design of ejectors, but very little to allow rating of existing equipment for varying duties. The methodology in Petro-SIM was developed by KBC and gives good performance over a wide range of normal industrial applications. For reliable detailed calculations, refer to the expertise and experience of equipment manufacturers. When a non-steam flow is detected on the suction side, Petro-SIM converts this flow to an equivalent air mass load, which is reported among the results. An equivalent water vapour mass load is also reported, to allow comparison with certain design specifications (load curves). 800 v Steam Use Steam Use A Steam Use unit operation is any destination (or group of destinations!) that removes steam from the system. This steam can either be: l l (Partly) returned to the system as condensate. Lost to a process stream (i.e., via injection), to atmosphere, or to drain. A Steam Use item may represent any number of constituent steam users and can thus be used to greatly simplify the PFD lay-out. For more information, refer to the Theory page. The recovered condensate and the lost condensate exit the use group in separate streams, which can be routed appropriately. Refer to Energy System Modelling for general information about modelling utility systems and use of the NBS fluid package. 1. To add a Steam Use object to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Steam Use (or click and drag it to the flowsheet). A Steam Use object is added to the active flowsheet. 3. In the Steam Use property view, enter or view the properties in these tabs: l Design l Worksheet l Results 4. To ignore the Steam Use object during calculations, check Ignored. v 801 Chapter 8: General Unit Operations Design Tab The Steam Use Design tab consists of four pages: Connections This page shows all connections of the Steam Use group. You can specify the connections for inlet steam and outlet condensate streams on this page. The energy stream connection for absorbed heat is optional. The name of the operation can be changed in the Name field. Parameters On this page, you may specify any number of constituent steam users, along with their "activity" (on or off), usage type ("live" or not, flow or duty), the amount of usage (either in terms of mass flow or in terms of heat duty) and their condensate recovery fraction. By default, the condensate temperature is the saturation temperature at the condensate's pressure. However, you can override this by specifying a value in the last column, to represent sub-cooling. For "live" steam users , the steam flow enters a process stream and the condensate can therefore not be recovered. Also, live-steam users are, by definition, "flow-based" users. 802 v Steam Use You can also add User Variables and Notes. Steam Use Theory The flow into a Steam Use group must be set by specifying constituent users on the Design tab, Parameters page. These consumers can be flow based or duty based. Live-steam users are automatically flow-based and allow no condensate return. Live Steam Consumption This is also termed direct steam usage: the steam enters a process stream. Typical examples of this are steam ejectors, strippers and fuel atomisers, for which the amount of steam needed should not vary significantly with the temperature of the steam. The water may be recovered somehow (e.g., as sour water in oil refineries), but this does not qualify as condensate. The heat duty of live-steam usage, although not particularly relevant, is estimated from the pressure and temperature of the steam and its "condensate" as it leaves with the process stream. Heating Steam Consumption This is also termed indirect steam usage, and is normally duty based: more or less steam is needed, depending on the quality of that steam. Typical examples are column reboilers, feed preheaters, etc. The steam normally exits as relatively clean condensate, but it remains up to the user to define – via the recovery fraction – how much of that condensate is, in fact, recovered in clean form. This can be anywhere from 0 to 100%. Any unrecovered condensate must exit via the Lost stream and could still be routed to waste-water collection or into a process stream, as necessary. v 803 Chapter 8: General Unit Operations For every heating-steam user, a condensate temperature may be defined to override the default saturation temperature. The "recovered condensate" outlet flow will have the mix temperature of all contributing condensate flows. Pressure and Temperature Drop By default, it is assumed that any condensate emerges at the same pressure as the entering steam and at saturation temperature. The user can specify other (lower!) temperatures or pressure, as needed. 804 v Deaerator Deaerator A Deaerator uses steam to perform heat treatment of (high-quality) demineralized water, mainly to remove oxygen and so reduce the corrosivity of the resulting boiler feed water (BFW). The oxygen is removed, along with some water vapour, through a vent to atmosphere. The steam inlet essentially boils the deaerator feed water (DFW), so that both the outlet water (BFW) and the vent are at saturation temperature for the specified operating pressure of the vessel. The required amount of BFW out of the deaerator is normally determined by downstream equipment, such as boilers and desuperheaters. The operating pressure and the amount of vent steam are the only required equipment parameters to be entered by the user. From this information, along with the conditions of the steam, the recovered condensate and the make-up water, the mass flows of steam and DFW are calculated, via a combined heat and mass balance. You can optionally override the mix temperature of condensate and make-up water by specifying a preheat temperature. Refer to Energy System Modelling for general information about modelling utility systems and use of the NBS fluid package. 1. To add a Deaerator unit operation to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Deaerator (or click and drag it to the flowsheet). A Deaerator unit operation is added to the active flowsheet. 3. In the Deaerator view, enter or view the properties in these tabs: v 805 Chapter 8: General Unit Operations Design l Worksheet l Performance l Plant Data 4. To ignore the Deaerator during calculations, check Ignored. l Design The Deaerator Design tab contains the following pages: Connection This page shows all of the connections to the Deaerator. You can specify the inlets (recovered condensate, make-up water and steam) and outlets (BFW and vent) on this page. The name of the operation can be changed in the Name field. Parameters The required parameters are: l l Operating pressure - This is also the pressure of the two outlet streams. It should be higher than atmospheric, but lower than any of the inlet pressures. A default pressure is provided automatically. Vent Mass flow - If unknown, the vent flow rate can simply be set to a relatively small value. For example, about 0.1% of the (expected) BFW flow. The vent flow is specified as an absolute flow and not as a ratio. An optional parameter is: 806 v Deaerator l Preheat temperature - This will override the mix temperature of recovered condensate and make-up water. It may be higher or lower than the mix temperature and thus represent a positive or a negative heat duty. You can also add User Variables and Notes. Performance The Deaerator Performance tab contains the following information: v 807 Chapter 8: General Unit Operations Result Description Mass flows and temperatures of the feed water flows Deaerator feed water (DFW) mass flow is normally back-calculated from boiler feed water (BFW) requirements. Its temperature depends on the mix of recycled condensate and fresh make-up water and on the amount of DFW preheating (normally with “waste heat”). Generally, DFW should stay at least 10°C below BFW (operating) temperature. Mass flow and temperature of the boiler feed water This is the mass flow and temperature of the “product” water. Its pressure and temperature equal the operating conditions of the deaerator. Steam mass flow This is the flow of steam needed to bring the DFW to boiling point at the operating pressure of the deaerator. Steam mass ratio This is the fraction of steam used in relation to the total BFW mass flow. A measure of efficiency, mostly dependent on the degree of DFW preheating, but also on the size of the vent flow. Max. condensate return The heat and mass balances impose an upper limit on how much condensate can be returned at the current condensate conditions. If the condensate gets hotter, more can be recovered; if it gets colder, less can be returned. Plant Data The Deaerator Plant Data tab allows quick comparison between latest calculation results and any metered plant data. 808 v Desuperheater Desuperheater A Desuperheater injects (boiler feed) water into a steam flow, to lower the temperature of that steam – that is: to reduce its amount of superheat. The outlet flow should still be all steam (i.e. "dry"), but may be fully desuperheated, i.e. practically at saturation temperature. Desuperheaters often function as letdowns between steam headers, to control both the temperature and the pressure of the destination header, but also to control the temperature out of boilers and steam turbines, or to ensure a specific temperature into certain process steam users. The required amount of injection water is determined, via combined heat and mass balance, from either the inlet steam flow or from the (desired) outlet steam flow, along with the pressure and temperature conditions of all three streams involved. If no water stream is connected, the item is treated as a regular letdown valve, without desuperheating. Refer to Energy System Modelling for general information about modelling utility systems and use of the NBS fluid package. 1. To add a Desuperheater unit operation to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Desuperheater (or click and drag it to the flowsheet). A Desuperheater unit operation is added to the active flowsheet. v 809 Chapter 8: General Unit Operations 3. In the Desuperheaterview, enter or view the properties in these tabs: l Design l Worksheet 4. To ignore the Desuperheater during calculations, check Ignored. Design Modify the Desuperheater Design tab settings on these pages: Connections This page shows all connections of the Desuperheater. You can specify the inlet steam and injection water and the outlet steam. The name of the operation can be changed in the Name field. Note that the Water IN stream is optional. Without it, the operation is treated as a simple isenthalpic letdown from inlet to outlet pressure. Parameters The applicable parameters are: l l 810 v Pressure - This is also the pressure of the outlet steam flow and should not be higher than either of the inlet pressures. Temperature - Optional. If nothing is specified here, the model uses the saturation temperature at the specified operating pressure, as shown in the last row of the table. However, if no water stream is attached then this entry is not available and ignored since there is no means of achieving this control temperature. Desuperheater Max. temp. without desup. is the temperature that would emerge from a simple letdown to the specified pressure. If no injection water is connected, the model will return this as the outlet temperature. Any manually specified outlet temperature for desuperheating must be lower than this, but higher than the saturation temperature. You can also add User Variables and Notes. v 811 Chapter 8: General Unit Operations Steam Header Steam headers are key infrastructure components of any steam network. It can be a site-wide distribution header or local to a particular process. It functions as a combined mixer/splitter—many flows of steam at different qualities (pressure and temperature) may enter a header, where they are assumed to mix ideally inside the header. Many flows of steam may exit the header, but PetroSIM assumes these to be at identical pressure and temperature conditions. Petro-SIM allows any number of headers in a steam network, each defined by its particular operating pressure. When dropping a header onto a flowsheet, Petro-SIM automatically attaches: l l l Condensate drain stream, to represent any condensate removal that normally takes place via the steam traps. This flow will only be greater than zero if the header conditions are at saturation. Vent stream, to offer an outlet for surplus steam. The flow of this stream only needs to be set explicitly when you are in Calibration mode, that is, when heat and mass losses are not fixed. When losses are fixed, the vent flow is determined automatically. Mass-loss stream, to represent any mass imbalance between the known inlet and outlet flows. This could have a negative value, if a mass "gain" is calculated. The mass loss stream is assumed to have the same enthalpy as any other stream exiting the header and this heat flow is separate from the amount reported as "heat loss". First, the header mixes all incoming steam flows ideally and calculates the resulting vapour fraction at the specified operating pressure. If the vapour fraction is less than 1, this indicates condensation and an amount of liquid water is removed through the condensate drain, such that the other outlet streams contain saturated, but entirely dry, steam. The overall mass balance can be done using one of two modes: l l Fixed Losses mode: Heat and mass losses are fixed and one of the regular steam flows (for example, a let-down stream), which you select, becomes the degree of freedom for balancing the header. When a header is first added, it is set to the Fixed Loss mode with all losses set to zero. Calculate Losses mode: This mode determines any unaccounted heat and mass losses. For this to work, all inlet and outlet flows, except condensate and mass loss, must be specified. Refer to Energy System Modelling for general information about modelling utility systems and use of the NBS fluid package. 1. To add a Steam Header unit operation to your simulation, from the Home tab, open the Operations, General palette (or press F4). 812 v Steam Header 2. Double-click Steam Header (or click and drag it to the flowsheet). A Steam Header unit operation is added to the active flowsheet. 3. In the Steam Header view, enter or view the properties in these tabs: l Design l Worksheet l Performance 4. To ignore the Steam Header during calculations, check Ignored. Design Modify the Steam Header Design tab settings on these pages: Connections On the Connections page, you can specify the inlet and outlet streams attached to the Header. You can change the name of the operation in the Name field. v 813 Chapter 8: General Unit Operations Parameters The Parameters page contains information as follows: Parameter Description Pressure This is the single operating pressure needed to describe the behaviour of the header. All outlet streams are set to this pressure and the header’s vapour fraction is calculated using this pressure. Temperature This is the single operating temperature of the header. All outlet streams are set to this temperature. In Calculate Losses mode, it may be set higher or lower than the ideal mix temperature of the inlet streams and so imply heat gain or loss. The temperature needs to be specified. In Fix Losses mode, this temperature is calculated, but may be 814 v Steam Header Parameter Description fixed by checking the Control to current temperature option . Control to current temperature This uses water injection to keep the header temperature constant while in Fixed Losses mode. A water connection is required. The water injection flow could end up being calculated as negative, if the temperature set point is higher that the ideal mix temperature of the inlet streams. Equalize inlet pressures Check to automatically set all inlet flows to have the specified header pressure. This can reduce data entry but could also cause inconsistencies if those pressures are already somehow determined upstream of the header. Mass and Heat losses Select: l l Fix to evaluate changes to the system, such as during optimization, what-if analysis, etc.. The amounts of heat and mass loss may be specified manually. Calculate to establish a base case (i.e., calibrate), by deriving heat and mass losses from known (measured) data. Use base-case vent flow as minimum limit. Check to ensure that the current vent, which may be at a minimum required flow, does not get reduced from its base-case value but may only increase, if necessary. Disable integrated recycle Used only for model debugging. The header model has integrated "recycle" functionality to cope with variable-temperature headers supplying duty-based steam consumers. If the network fails to converge, one debugging option is to disable these recycles, one header at a time, and insert an actual recycle object on each of its outlets to other equipment. Alternatively, you could enable Temperature control and so create a fixed-temperature header, which makes the network easier to solve, although possibly less realistic You can also add User Variables and Notes. Performance The Steam Header Performance tab displays key results of the Header calculations. v 815 Chapter 8: General Unit Operations This tab contains the following information: Result Description Mass Balance The total steam (including vent) and condensate outlet flows are subtracted from the total steam inlet flow to give the loss or gain, which is then also expressed as a percentage of the inlet flow. Heat Balance The total enthalpy flows into and out of the header are shown and the imbalance is reported as a fraction of the inlet heat. This does not include the heat involved in any flow of mass loss (or gain). 816 v Hydraulic Turbine Hydraulic Turbine The Hydraulic Turbine model essentially provides a "wrapper" around the Expander model.This avoids the warning about there being liquid in the feed stream. This unit operation is also known as Hydraulic Power Recovery Turbine (HPRT) and occasionally as Liquid Expander. 1. To add a Hydraulic Turbine to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double click Hydraulic Turbine (or click and drag it to the flowsheet). A Hydraulic Turbine is added to the flowsheet. 3. Refer to the Expander model for details about the Hydraulic Turbine property view tabs: l Design l Rating l Worksheet l Performance 4. To ignore the Hydraulic Turbine during calculations, check Ignored. Previously, it may have been tempting to evaluate hydraulic turbines by using the standard pump model and running this in reverse, to obtain a power generation. If no evaporation occurs (i.e., when the fluid involved remains incompressible), the Bernoulli calculation employed by the pump model and the more thorough entropy-based calculations of the expander will give virtually identical results. In most real-life applications, (partial) evaporation does occur inside a hydraulic turbine and in those cases the expander, or rather, the hydraulic turbine, gives the v 817 Chapter 8: General Unit Operations more accurate, higher power generation resulting from the volume increase. It will also more accurately predict the temperature reduction of the outlet stream, which is especially important for modelling cryogenic processes, such as LNG. 818 v Steam TurboGen Steam TurboGen The Steam Turbo-Generator (STG) unit operation allows for up to 10 consecutive stages, with any combination of induction (pass-in) steam flows and extraction (pass-out) flows. It is assumed to be used for generating electrical power, but this could equally be interpreted as delivery of shaftwork. You may either: a. Fix the power generation of the overall turbine, in which case a maximum of any two unknown flow rates can be derived. b. Let the power be a variable. In this case, only one flow rate may be unknown and the power (or shaftwork) output is calculated. It is not possible to calculate the power generated per stage in a meaningful way. Desuperheating of extraction/exhaust flows must be modelled separately. Also, the actual cooling water stream is not part of the model, but may be modelled separately using the exported condensing duty, if needed. Refer to Energy System Modelling for general information about modelling utility systems and use of the NBS fluid package. 1. To add a Steam TurboGen unit operation to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Steam TurboGen , or click and drag it to the flowsheet. A Steam TurboGen unit operation is added to the active flowsheet. v 819 Chapter 8: General Unit Operations 3. In the Steam TurboGen view, enter or view the properties in these tabs: l Design l Worksheet l Performance l Plant Data 4. To ignore the Steam TurboGen during calculations, check Ignored. Design The Steam TurboGen Design tab consists of these pages: Connections Use the Connections page to define which steam streams enter and leave the turbo-generator. A minimum of one inlet and one outlet are required. You must attach an energy stream for the generated power. In the case of condensing turbines, connecting an energy stream to export the heat removed in the condenser is optional. The inlets and outlets may be listed in any order. They are assigned to their own stages on the Stage-wise page. 820 v Steam TurboGen Stage Connections Each stage must be delimited by one inlet and one outlet. In the figure below, for example, the middle stage is delimited by the extraction flow of the upstream stage and the induction stream of the downstream stage. The model carefully checks whether the sequence of connected inlets and outlets makes sense from a pressure perspective. The pressure must drop in every stage and the pressure of any induction flow must not conflict with this. One condensing (vacuum) stage is allowed and only as the very last, lowest-pressure outlet. The model calculates the condensing duty as the minimum amount of heat to be removed to turn the entire vacuum outlet flow into fully-saturated liquid water. It can also calculate a coolingwater mass-flow requirement from the specified Cooling water deltaT. v 821 Chapter 8: General Unit Operations Overall Use this page to specify parameters that affect the operation/calculation of the turbine as a whole. Parameters affecting the individual stages are specified on the Stage-wise page. Use... Power Generation Description Select: l l Stage efficiency type specification Select: l l Mechanical losses Variable to indicate that the power output should be calculated as a result of specified steam flow rates. Fixed and then enter a value, to let the model calculate the required flow rates that give the specified power output. Fixed efficiency, to enable entry on the Stage-wise page of fixed percentages for the efficiency of each individual stage. Willans coefficients, to enter Willans-line coefficients on the Stage-wise page, to represent mass-flow dependent (i.e., variable) efficiency per stage. These coefficients must be obtained through suitable calibration methodology. This represents the losses due to friction in the turbine itself. The default value of 3% means that 3% of the energy taken from the steam ends up being lost as heat to the environment (mainly due to friction), while the remaining 97% finds its way to the power generator. NOT relevant when using calibrated Willans coefficients 822 v Steam TurboGen Use... Description for each stage. Generator efficiency This is the percentage of energy successfully converted to electrical power inside the generator. Default value: 97%. NOT relevant when using calibrated Willans coefficients for each stage. Cooling water deltaT This is only relevant for condensing turbines. Enter the (allowed or measured) temperature rise of the cooling water, so the model can work out the flow rate of cooling water required to remove the necessary heat from the condenser. Stage-wise Use the Stage-wise page to assign the streams that were added via the Connections page as inlets and outlets to particular stages. Also use this page to specify stage-specific efficiency parameters. Efficiencies The turbo-generator can be configured with fixed isentropic stage efficiencies. This is easier conceptually, but less realistic. In reality, efficiency is load-dependent. Therefore, it is also possible to specify so-called Willans coefficients, which must be obtained from a separate calibration exercise. The Willans representation provides a linear model for load-dependent stage efficiencies. It requires one overall A coefficient for the entire unit and one separate C coefficient for each v 823 Chapter 8: General Unit Operations individual stage. The A coefficient must be between 0 and 1 and has a default value of 1. Each stage-specific C coefficient is a fixed amount of power that is subtracted from the ideal isentropic power recovery, to represent the inertia and frictional losses of that stage. The default value for each C coefficient is 0. With the default coefficient values, a Willans turbine has a fixed overall efficiency of 100%. A "Willans" turbine with coefficients A=0.8 and C=0 does not give the same results as a Fixed efficiency turbine with efficiency = 80% because the Willans approach works with different enthalpy definitions. The Willans approach allows for variable efficiency as a function of throughput, but strictly speaking it is not suitable for induction (pass-in) turbines. You can also add User Variables and Notes. Performance The Steam TurboGen Performance tab holds the following calculation results: Result 824 v Description Efficiency The overall isentropic efficiency of the turbine at its current operation. This is calculated from the actual total power output divided by the ideal power generation summed up over all the stages. Power generation The total power generated by the machine. Stage-wise results Displays the relevant results per stage. The flows are the amounts of steam entering (via induction) or leaving (via extraction) the turbo-generator. They are not the inter-stage flows. Steam TurboGen Result Description Condenser inlet vapour fraction The steam fraction of the mass flow entering the condenser. The "wetness" of this stream (i.e. the water content) equals 1 minus this vapour fraction. Cooling water flow The (minimum) amount of water needed in the condenser. Only for condensing turbines. Dependent on the delta T specified in the Overall page. Plant Data The Steam TurboGen Plant Data tab allows you to compare any relevant measured plant data for this unit operation with its latest calculation results. v 825 Chapter 8: General Unit Operations Basic Boiler The Basic Boiler unit operation can serve as a utility boiler with variable duty to balance steam demands. It is equivalent to a combination of the Boiler_A and Boiler_B models used in KBC's ProSteam™ Toolkit. The Basic Boiler unit operation can calculate either: l l The heat duty for generating a specified steam flow at given conditions from boiler feed water at given conditions. The amount of steam generated given a specified amount of heat supply. The fuel streams are represented as energy streams only. The energy stream connection for Stack heat loss is optional. Given stack pressure and temperature and the temperature of the combustion air, the model can usefully estimate the firing efficiency. The model does not carry out combustion calculations and does not check for thermodynamic feasibility. For such purposes, we recommend using the rigorous Steam Generator unit operation. Refer to Energy System Modelling for general information about modelling utility systems and use of the NBS fluid package. 1. To add a Basic Boiler unit operation to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Basic Boiler(or click and drag it to the flowsheet). A Basic Boiler unit operation is added to the active flowsheet. 826 v Basic Boiler 3. In the Basic Boiler view, enter or view the properties in these tabs: l Design l Worksheet l Performance l Plant Data 4. To ignore the Basic Boiler during calculations, check Ignored. Design The Basic Boiler Design tab consists of these pages: Connections The Connections page defines the boiler connections. Boiler feed water, Steam, and Blowdown are required material stream connections. At least one fuel must be connected, but note that these are energy streams. Up to three of these "energy supplies" can be specified. Stack heat loss is an optional energy connection that holds the heat duty of the flue gas stream. It does not represent the actual flue gas material stream and it does not include the radiation heat losses. v 827 Chapter 8: General Unit Operations Blowdown water is removed to prevent a build-up of contaminants, but this contamination is not modelled separately. The blowdown mass flow is expressed as a percentage of the total steam generation. The amount of boiler feed water required is the sum of steam and blowdown flows. Parameters Use the Parameters page to specify the basic design and operating parameters. 828 v Basic Boiler Parameter Description Steam temperature The (superheated) temperature at which the steam becomes available to the rest of the system. Make sure that this is higher than the saturation temperature (i.e. higher than the Steam drum temperature). Steam drum temperature The temperature inside the evaporation drum of the boiler. The saturation temperature for the pressure of the produced steam and thus also the temperature of the blowdown stream. Blowdown ratio Specified as a percentage relative to the steam mass flow and has a default value of 2%. Heat loss fraction Heat losses other than from stack flue gas can be specified as a percentage of the total current fuel duty, or of total rated (i.e. design) duty. By default, this is set to 3% of rated duty. These losses normally represent radiation losses. Rated steam load This is the maximum steam load during normal operation, for which the boiler was designed and the number should come from the design documentation (or boiler plate) for the unit. Any load-based efficiency curve specified on the Fuel Info page uses this number to determine the fractional steam load. Rated fuel duty This is the designed amount of (primary) fuel, in energy terms, needed to produce the rated steam load. This number is used to calculate the radiation heat losses as a fraction of rated fuel duty. The Heat losses options are used to distinguish between two different modes of calculating those losses. In the vast majority of cases, these losses should be calculated as a percentage of Rated fuel duty. The total fired duty and absorbed duty are only determined by the amount of steam generated and the firing efficiency and are not affected by the heat loss fraction. The amount of heat that does not go into steam production leaves either with the regular flue gas via the stack, or through "other" losses (e.g. radiation). The split of losses between flue gas and radiation is effectively set by the "heat loss fraction". If the heat loss fraction is set too high, the flue gas heat flow may be calculated as a negative value and generate a warning. Fuel Info The Fuel Info page holds all information for how the heat duty is provided to the boiler. v 829 Chapter 8: General Unit Operations Fuels are represented as energy streams. They can only be specified by name and the inputs are related to the (relative) amounts of each fuel and to their firing efficiency. Up to three different fuels may be connected and you may specify a separate efficiency (curve) for each fuel. The overall efficiency, reported on the Performance tab, is a duty-weighted average of the fuel-specific efficiencies . To specify the fuel amounts explicitly, select Duties and then enter fixed amounts for those duties in the third row of the table. This then fixes the overall heat duty of the boiler and thereby also the total steam flow generated. If the steam flow is determined by downstream requirements (e.g., balancing a header), as is normally the case for utility boilers, then you should only select Fractions and let the model calculate how much duty is needed from each fuel to generate the required steam. The sum of fuel fractions must add up to 1. You can specify a fixed firing efficiency, or coefficients for a 2nd-order polynomial to represent a load-dependent efficiency curve. The efficiency curves use fractional load as the variable. The fractional load (f) comes from dividing the actual (current) load by the rated steam load (as entered on the Parameters page). Efficiency(η ) = p 1 + p 2 * f + p 3 * f 2 Where f= (Current steam mass flow) / (Rated steam mass flow) The coefficients p can have any value. To specify a fixed efficiency, rather than a curve, only enter i a value for coefficient p . 1 830 v Basic Boiler To derive a fixed efficiency from stack conditions (temperature and oxygen content) and ambient temperature, click Calc. p1 coeff. You can also add User Variables and Notes. Performance The Basic Boiler Performance tab presents key results for this unit operation. Result Description Steam load fraction This is the fraction of the rated (design) boiler load that is currently being produced. Absorbed heat duty The total heat duty transferred into the steam flow. This does not include the heat that exits via the blow-down water. Fired fuel duty The total fuel duty. A summation of the duties of any separate fuels. Overall firing efficiency Calculated from dividing the Absorbed heat duty (heat into steam only) by the total Fired fuel duty. Design efficiency This is calculated by dividing the heat absorbed in the rated steam load by the rated fuel duty. Plant Data The Basic Boiler Plant Data tab allows you to compare any relevant measured plant data for this unit operation with its latest calculation results. v 831 Chapter 8: General Unit Operations 832 v Turbine Group Turbine Group Similar to the Steam Use and the Steam Gen Group unit operations, the Turbine Group unit operation allows you to define a set of similar steam turbines, meaning turbines with the same inlet steam conditions and the same outlet steam pressure. Any turbines in the group whose outlets are desuperheated also need to make use of the same desuperheating water. This provides easier data entry and reduces complexity and clutter on the flowsheet. Refer to Energy System Modelling for general information about modelling utility systems and use of the NBS fluid package. 1. To add a Turbine Group unit operation to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Turbine Group (or click and drag it to the flowsheet). A Turbine Group unit operation is added to the active flowsheet. 3. In the Turbine Group view, enter or view the properties in these tabs: l Design l Worksheet l Results 4. To ignore the Turbine Group during calculations, check Ignored. Design The Turbine Group Design tab consists of these pages: Connections The Connections page lets you define or view the connections for this unit operation. The v 833 Chapter 8: General Unit Operations group has only one steam inlet, so all turbines in the group must use the same steam quality. All group members must also have the same outlet pressure, but they may have different outlet temperatures, depending on their particular efficiency. The various outlet streams are all mixed to give a single outlet stream with a weighted-average outlet temperature. A desuperheating water stream is only required if any of the turbines are specified as having their outlet desuperheated. The duty (i.e., power or shaftwork) can be exported as a combined energy stream, but this is optional. Status Info Use the Status Info page to: l l l l 834 v Add or remove turbine to/from the group. Specify the turbine design duty in terms of power (or shaftwork). Specify the turbine status as On, Off, or Rolling (i.e., hot stand-by). Specify the mass flow used when in Rolling mode. Turbine Group Flows/Duties Normally, when establishing a base-case scenario, turbines are set up as flow-based. When you need to make and evaluate changes to the system, they should be changed to duty-based, since changing steam qualities affect the required steam mass flow. Because individual turbines may be switched to or from electric motors, the model keeps track of the last operating (L.O.) mass flow and uses this number when the turbine is switched back on again. The steam temperature and vapour fraction pre desuperheating are reported in the table. The desuperheating target temperature can be specified in the Desup.T column, but is optional. If used, the temperature value should be above the saturation temperature, which is shown below the column (T_sat @ P_out = ...). Efficiency Each turbine can be given its own fixed isentropic (i.e., adiabatic) efficiency. If you know the duty needed from the turbine, but not its efficiency, then you can specify it as a duty-based item, enter the duty and let the model suggest a likely Estimated Efficiency, based on a proprietary KBC correlation. You may then decide to transfer this estimate into the column for Used Efficiencies. The Mechanical Loss fraction determines how much of the energy taken out of the steam is lost to friction, etc., rather than being converted to useful work. For example, a Mech. Loss of 3% means that 97% of the enthalpy taken from the steam flow is converted into useful shaftwork. v 835 Chapter 8: General Unit Operations You can also add User Variables and Notes. Results The Turbine Group Results tab lists the key results that cannot be found on the Worksheet tab. The Total steam out may be slightly higher than the Total steam in if desuperheating plays a role. 836 v Steam Gen Group Steam Gen Group The Steam Gen Group unit operation, similar to Steam Use, allows you to define a group of steam generators, normally waste-heat boilers. All waste-heat boiler members of the group must use the same feed water provider and are assumed to produce the same quality of steam. The group members are fixed-duty steam producers that normally depend on process duties for the necessary heat. In other words, they are not utility boilers and cannot be used to control an overall or local steam balance. Grouping waste-heat boilers together simplifies the flowsheet and allows quicker access to the data. The combined blow-down water from each generator leaves the unit operation in a single outlet stream at saturation conditions. Refer to Energy System Modelling for general information about modelling utility systems and use of the NBS fluid package. 1. To add a Steam Gen Group unit operation to your simulation, from the Home tab, open the Operations, General palette (or press F4). 2. Double-click Steam Gen Group (or click and drag it to the flowsheet). A Steam Gen Group unit operation is added to the active flowsheet. 3. In the Steam Gen Group view, enter or view the properties in these tabs: l Design l Worksheet l Results 4. To ignore the Steam Gen Group during calculations, check Ignored. Design The Steam Gen Group Design tab consists of these pages: v 837 Chapter 8: General Unit Operations Connections The Connections page displays all Steam Gen Group connections. You can specify the connections for inlet water, outlet steam and blowdown on this page. The energy stream connection for absorbed heat is optional. The name of the operation can be changed in the Name field. Parameters On the Parameters page, you can specify any number of constituent steam generators, along with their activity (on or off), basis (flow or duty), the amount of usage (either in terms of mass flow or in terms of heat duty) and the blowdown (as a percentage of steam generated). In addition you may specify the steam temperature. If no steam temperature is entered, saturation conditions are assumed by default. This page is used for all the relevant details of the members of the group. The inlet and outlet streams, including the energy stream connection, should not be used to specify flows or duties. You can also add User Variables and Notes. 838 v Steam Gen Group Results The Steam Gen Group Results tab shows a few relevant results for the overall group. v 839 Chapter 9: Separation Unit Operations From the Home tab, click Separation on the Operations group to view the palette (or press F4). Petro-SIM offers these Separation unit operations: l l l l l l l l l l l l l l Distillation Column Sub-Flowsheet Refluxed Absorber Sub-Flowsheet Reboiled Absorber Sub-Flowsheet Absorber Column Sub-Flowsheet Liquid-Liquid Extractor Three Phase Distillation Short-Cut Distillation Component Splitter Blank Column Sub-Flowsheet Simple Solid Separator Cyclone Hydrocyclone Rotary Vacuum Filter Baghouse Filter v 841 Chapter 9: Separation Unit Operations Column Sub-flowsheet Environment The Column Sub-flowsheet is a special sub-flowsheet type containing equipment and streams that exchange information with the parent flowsheet through the connected internal and external streams. The Column Sub-flowsheet displays as a single, multi-feed multi-product operation in the Main environment. Having a Column Sub-flowsheet provides a number of advantages: l l l l Isolation of the Column solver Optional use of different property packages Construction of custom templates Ability to solve multiple towers simultaneously You can also work inside the Column Sub-flowsheet to focus your attention on the Column. When you move into the Column Sub-flowsheet environment, the Main simulation is cached. All aspects of the Main environment are paused until you exit the Column environment. You can also enter the Column environment when you want to create a Custom Column configuration. Side equipment such as pumparounds, side strippers and side rectifiers can be added from the Column property view in the Main simulation. If you want to install multiple tray sections or multiple Columns, you need to enter the Column build environment. Once inside, you can access column-specific operations (tray sections, heaters/coolers, condensers, reboilers, etc.) and build the Column as you would any other flowsheet Isolation of the Column Solver One advantage of the Column build environment is that it lets you make changes and focus on the Column without requiring a recalculation of the entire flowsheet. When you enter the Column build environment, Petro-SIM clears the desktop by caching all views that were open in the parent flowsheet. Then the views that were open when you were last in the Column build environment are re-opened. Once inside the Column build environment, you can access profiles, stage summaries and other data, as well as make changes to column-specifications, parameters, equipment, efficiencies, or reactions. In the Column sub-flowsheet, you can view the Workbook or PFD for either the Parent flowsheet or sub-flowsheet by using Workbooks or PFDs on the Tools menu. 842 v Column Sub-flowsheet Environment When you have made the necessary changes, run the Column to produce a new converged solution. The parent flowsheet cannot recalculate until you return to the parent build environment. The sub-flowsheet environment permits easy access to all streams and operations associated with your Column. To view the sub-flowsheet, right-click the column in the Navigator and choose Enter "column" environment. If you want to access information regarding Column product streams, open the Workbook (CTRL+W) to view the Column workbook, which displays the Column information exclusively. Main/Column Sub-flowsheet Relationship Unlike other unit operations, the Column contains its own sub-flowsheet, which in turn, is contained in the Parent (usually the main) flowsheet. When you are working in the parent flowsheet, the Column displays just as any other unit operation, with multiple input and output streams and various adjustable parameters. If changes are made to any of these basic Column parameters, both the Column sub-flowsheet and parent flowsheet are recalculated. When you install a Column, Petro-SIM creates a sub-flowsheet containing all operations and streams associated with the template you have chosen. This sub-flowsheet operates as a unit operation in the main flowsheet. The figure shows this concept of a Column sub-flowsheet within a main flowsheet. v 843 Chapter 9: Separation Unit Operations Main Flowsheet/Sub-flowsheet Concept Consider a simple absorber in which you want to remove CO from a gas stream using H O as the 2 2 solvent. A typical approach to setting up the problem would be as follows: 1. Create the gas feed stream, FeedGas and the water solvent stream, WaterIn, in the main flowsheet. 2. Click Absorber Column Sub-Flowsheet from the Separation palette and specify the stream names, number of trays, pressures, Estimates, and Specifications. You must also specify the names of the outlet streams, CleanGas and WaterOut. 3. Run the Column from the main flowsheet Column property view. When you connected the streams to the tower, Petro-SIM created internal streams with the same names. 844 v Column Sub-flowsheet Environment A sub-flowsheet stream connected to a stream in the main flowsheet is automatically given the same name with @Sub-flowsheet tag attached at the end of the name. An example is the stream named WaterIn has the subflowsheet stream named WaterIn@Col1. The Connection Points or Labels serve to connect the main flowsheet streams to the subflowsheet streams and facilitate the information transfer between the two flowsheets. For instance, the main flowsheet stream WaterIn is connected to the sub-flowsheet stream WaterIn. The connected streams may not have the same values. All specified values are identical, but calculated stream variables can be different depending on the fluid packages and transfer basis (defined on the Flowsheet tab). When working in the main build environment, you see the Column just as any other unit operation, with a property view containing parameters such as the number of stages, and top and bottom pressures. If you change one of these parameters, the sub-flowsheet recalculates (just as if You had clicked the Run button); the main flowsheet also recalculates once a new Column solution is reached. If you're inside the Column sub-flowsheet build environment, you're working in an entirely different flowsheet. If you delete any streams connected to the Column in the main flowsheet, these streams are also deleted in the Column sub-flowsheet. To make a major change to the Column such as adding a reboiler, you must enter the Column sub-flowsheet build environment. When you enter this environment, the main flowsheet is put on hold until you return. Connections Page (Column Runner) To open the Column Runner (inside the Column sub-flowsheet) Connections page, you must first enter the Column environment. From the Column tab, click tab. Column View to view the column's connections on the Design v 845 Chapter 9: Separation Unit Operations All inlet feed and energy streams, as well as the associated stage, and the outlet liquid, vapour and water product streams and locations are displayed. You can set or modify these pressure settings: l l l l dP Top - the Delta pressure at the top (condenser) stage. dP Bot - the Delta pressure at the bottom (reboiler) stage. P Top - the top stage pressure P Bot - the bottom internal stage pressure. In the the Stage Numbering area, set to either Top Down to Bottom Up. You can connect or disconnect streams and change the stream location. If you add a new stream to the inlet or outlets, the stream is created inside the Column, but it is not automatically transferred into the main flowsheet. Refer also to Connections Page (Main Flowsheet) for more details. Column Sub-flowsheet Unit Operations The procedure for installing unit operations in a Column sub-flowsheet is the same as in the main flowsheet. Only those operations that are applicable to Column operations are available in the Column sub-flowsheet environment from the Column tab. To see all Unit Operations that can be used in the Column sub-flowsheet including unit operations available in Dynamics mode, press F12. 846 v Column Sub-flowsheet Environment Most operations are identical to those available in the Main flowsheet in terms of specified and calculated information, property view structure, etc. In addition to adding Material and Energy streams, you can also add the following unit operations to the column sub-flowsheet: l l l l l l l l l l l l l l Partial Condenser Cooler Heater Total Condenser Heat Exchanger Separator 3-Phase Condenser Pump Valve Tray Section Mixer Tee Reboiler Balance When in Dynamics mode, the following operations are available: l l l Boolean (And, CountDown, countUp Latch, Not OffDly, OnDly, Or, XOr) Digital Pt Controller (MPC. PID, Ratio, and Split Range) v 847 Chapter 9: Separation Unit Operations l l Selector Block Transfer Function Block The bypasses and side operations (side strippers, pumparounds, etc.) are available from the Side Ops tab of the Column property view. Condenser The Condenser unit operation is used to condense vapour by removing its latent heat with a coolant. In Petro-SIM, the Condenser is used only in the Column sub-flowsheet environment and is generally associated with a Column tray section. Some Petro-SIM pre-defined templates come defined with a condenser already attached to the tower (for example, Distillation Column). There are four types of condensers: Condenser Type Description Partial Feed is partially condensed; there are vapour and liquid product streams. The partial condenser can be operated as a total condenser by specifying the vapour stream to have zero flow rate. The Partial condenser can be used as a Total condenser by specifying the vapour flow rate to be zero. Total Feed is completely condensed; there is a liquid product only. Three-Phase - Chemical There are two liquid product streams and one vapour product stream. Three-Phase - Hydrocarbon There is a liquid product stream, water product stream, and one vapour product stream. 1. To add a Condenser unit operation to the column, from the Column tab, select one of the following condenser types: Partial Condenser Total Condenser 3-phase Condenser 848 v Column Sub-flowsheet Environment Optionally, press F12 and select the unit operation that you want to add from the UnitOps view. A Condenser unit operation is added to the column sub-flowsheet. In the Condenser property view, you can select the condenser Type from the drop-down list to switch between condenser types without having to delete and reinstall a new piece of equipment. If you switch between the condenser types, the pages change appropriately. For instance, the connections page for the Total Condenser does not show the vapour stream. If you switch from the Partial to Total Condenser, the vapour stream is disconnected. If you then switch back, you have to reconnect the stream. 2. In the Condenser property view, enter or view the properties on these tabs: l Design l Rating l Worksheet l Performance l Dynamics - this tab is only available in Dynamics mode. 3. To ignore the vessel operation, select the Ignored check box. v 849 Chapter 9: Separation Unit Operations Design The Condenser Design tab contains the following pages: Connections Use the Connections page to specify the operation name, as well as the feed(s), vapour, water, reflux, product, and energy streams. The Total Condenser does not have a vapour stream, as the entire feed is liquefied. Neither the Partial nor the Total condenser has a water stream. The Connections page shows only the product streams, which are appropriate for the selected condenser. The condenser is typically used with a tray section, where the vapour from the top tray of the Column is the feed to the condenser and the reflux from the condenser is returned to the top tray of the Column. Parameters The condenser parameters that can be specified include the following: Pressure Drop The Pressure Drop across the condenser (Delta P) is zero by default. It is defined in the following expression: P = Pv = Pl = P feed − ∆P 850 v Column Sub-flowsheet Environment where: P = vessel pressure P = pressure of vapour product stream v P = pressure of liquid product stream l P feed = pressure of feed stream to condenser ΔP = pressure drop in vessel (Delta P) You typically specify a pressure for the condenser during the Column setup, in which case the pressure of the top stage is the calculated value. Duty The Duty for the energy stream can be specified here, but this is better done as a Column specification from the Monitor or Specs page on the Column property view. If you specify the duty, it is equivalent to installing a duty Spec and a Degree of Freedom is used.This allows for more flexibility when adjusting specifications and also introduces a tolerance. The Duty should be positive, indicating that energy is being removed from the condenser feed. The steady state condenser energy balance is defined as: H feed − Duty = H vapour + H liquid where: H H H feed = heat flow of the feed stream to the condenser vapour liquid = heat flow of the vapour product stream = heat flow of the liquid product stream(s) It is better to use a Duty Spec than to specify the heat flow of the duty stream. Subcooling In some instances, you want to specify condenser subcooling. Subcooling applies only to the Total Condenser. In this situation, either the degrees of subcooling or the sub-cooled temperature can be specified. If one of these fields is set, the other is calculated automatically. Estimate Use the Estimate page to estimate the flows and phase compositions of the streams exiting the condenser. v 851 Chapter 9: Separation Unit Operations You can enter any value for fractional compositions and click Normalize Composition to normalize the values such that the total equals 1. This button is useful when many components are available, but you want to specify compositions for only a few. Petro-SIM also specifies any <empty> compositions as zero. Click Update Comp. Est. to calculate the phase composition estimates and remove any estimated values that you entered for the phase composition estimates. Click Clear Comp. Est. to clear the phase compositions estimated by Petro-SIM. This button does not remove any estimate values you entered. To clear all estimate values, click Clear All Comp. Est. 852 v Column Sub-flowsheet Environment You can also add User Variables and Notes. Rating The Condenser Rating tab contains only the Sizing page. Sizing Use the Sizing page to define the vessel's capacity. In the Geometry group, select either Cylinder or Sphere, and then enter the vessel's volume and/or dimensions. v 853 Chapter 9: Separation Unit Operations If the vessel has a boot, check This condenser has a boot, and then enter the dimensions. Performance Use the Condenser Performance tab to view the condenser's performance data on the Plots and Tables pages. In steady state, the displayed plots are all straight lines. From these pages you can view the calculated values and plot any combination of the calculated temperature, pressure, heat flow, enthalpy, or vapour fraction. At the bottom of either page, you can specify the interval size over which the values should be calculated and plotted. Plots Right-click the graph and choose Graph Control to modify the display of the plot using the Graph Control view. 854 v Column Sub-flowsheet Environment Tables Reboiler The Reboiler is a Column unit operation, where the liquid from the bottom tray of the Column is the feed to the reboiler and the boil-up from the reboiler is returned to the bottom tray of the Column. v 855 Chapter 9: Separation Unit Operations The reboiler is used to partially or completely vaporize liquid feed streams. You must be in a Column sub-flowsheet environment to install the reboiler. If you choose a reboiled absorber or distillation column template, it includes a Reboiler that is connected to the bottom tray in the tray section with the streams to reboiler and boilup. 1. To add a Reboiler unit operation to the column, from the Column tab, select Reboiler. Optionally, press F12 and select Reboiler from the UnitOps view. A Reboiler unit operation is added to the column sub-flowsheet. 2. In the Reboiler property view, enter or view the properties on these tabs: l Design l Rating l Worksheet l Performance l Dynamics - This tab is available only in Dynamics mode. 3. To ignore the vessel operation, select the Ignored check box. Design The Design tab contains four pages: Connections On the Connections page, specify the reboiler name and the feed(s), boilup, vapour draw, 856 v Column Sub-flowsheet Environment energy and bottoms product streams. The vapour draw stream is optional. Parameters On the Parameters page, specify the pressure drop and energy used by the Reboiler. The pressure drop across the Reboiler is 0 by default. The Duty for the energy Stream should be positive, indicating that energy is being added to the Reboiler feed(s). If you specify the duty, a degree of freedom is used. It is preferable to define a duty specification on the Monitor page or Specs page of the Column property view, instead of specifying this value here. It is better to use a duty Spec rather than specifying the heat flow of the duty stream. The steady state reboiler energy balance is defined as: v 857 Chapter 9: Separation Unit Operations H feed + Duty=H vapour + H bottom + H boilup where: H H H H feed = heat flow of the feed stream to the reboiler vapour bottom boilup = heat flow of the vapour draw stream = heat flow of the bottom product stream = heat flow of the boilup stream You can also add User Variables and Notes. Rating The Reboiler Rating tab contains only the Sizing page. Sizing Use the Sizing page to define the vessel's capacity. In the Geometry group, select either Cylinder or Sphere, and then enter the vessel's volume and/or dimensions. If the vessel has a boot, check This reboiler has a boot, and then enter the dimensions. Performance The Reboiler Performance tab consists of the Plots and Tables pages. From these pages you can view the calculated values and plot any combination of the calculated temperature, pressure, heat flow, enthalpy, or vapour fraction. At the bottom of either page, you can specify the interval size over which the values should be calculated and plotted. 858 v Column Sub-flowsheet Environment Plots Right-click the graph and choose Graph Control to modify the display of the plot using the Graph Control view. Tables Tray Section Every Column template includes at least one Tray Section. An individual tray has a vapour feed from the tray below, a liquid feed from the tray above and any additional feed, draw, or duty streams to or from that particular tray. v 859 Chapter 9: Separation Unit Operations 1. To add a Tray Section to the column, from the Column tab, select Tray Section. Optionally, press F12 and select Tray Section from the UnitOps view. A Tray Section unit operation is added to the column sub-flowsheet. 2. In the Tray Section property view, enter or view the properties on these tabs: l Design l Rating l Worksheet l Performance l Dynamics - This tab is available only when working in Dynamics mode. 3. To ignore the tray section unit operation, select the Ignored check box Design The Tray Section Design tab contains the following pages: Connections Use the Tray Section Connections page to specify the names and locations of vapour and liquid inlet, outlet, and feed streams and the number of stages. When you use a Column template, the default stream names associated with the template are inserted into the appropriate input cells. For example, in a Distillation Column, the Tray Section vapour outlet stream is To Condenser and the liquid inlet stream is Reflux. 860 v Column Sub-flowsheet Environment The following conventions are applied when naming and locating streams associated with a Column Tray Section: l l l When you select a tray section feed stream, Petro-SIM feeds the stream to the middle tray of the Column (for example, in a 20-tray Column, the feed would enter on tray 10). The location can be changed by selecting the desired feed tray from the drop-down list, or by typing the tray number in the appropriate field. Streams entering and leaving the top and bottom trays are always placed in the Liquid or Vapour Inlet/Outlet fields. Specifying the location of a Column feed stream to be either the top tray (tray 1 or tray N, depending on your selected numbering convention) or the bottom tray (N or 1) automatically results in the stream becoming the Liquid Inlet or the Vapour Inlet, respectively. If the Liquid Inlet or Vapour inlet already exists, your specified feed stream is an additional stream entering on the top or bottom tray, displayed with the tray number (1 or N). A similar convention exists for the top and bottom tray outlet streams (Vapour Outlet and Liquid Outlet). Side Draws Use the Side Draws page to specify the name and type of side draws taken from the tray section of your Column. v 861 Chapter 9: Separation Unit Operations From the Tray Section Side Draws group, select the type of side draw: l l l Vapour Liquid Water For each side draw that you add to the Tray Section, select the stream from the Draws column and then select the Tray Number from which it is taken. Parameters Use the Parameters page to set the number of trays in the Tray Section. The trays are treated as ideal if the fractional efficiencies are set to 1. If the efficiency of a particular tray is less than 1, the tray is modelled using a modified Murphree Efficiency. By default, the Use tray section name for stage name check box is checked. 862 v Column Sub-flowsheet Environment To change the pressure profile, in the Tray Section Type, select: l l l Standard - Used as default. Side Stripper - The pressure of the main tray section stage from which the liquid feed stream is drawn is used as the Side Stripper pressure, which is constant for all stages. Side Rectifier - The pressure of the main tray section stage from which the vapour feed stream is drawn is used as the Side Rectifier pressure, which is constant for all stages. v 863 Chapter 9: Separation Unit Operations To add trays to the Tray Section You can add or remove trays anywhere in the Column, especially if you have a complex column and you do not want to lose any feed or product stream information. 1. On the Parameters page, click Customize. 2. In the Change Number of Trays view, enter the number of trays you want to add in the Number of Trays to Add/Delete cell. 3. To specify where to add the trays in the Tray Section, select the tray number from the Tray to Add After or Delete First dropdown list. 4. Click Add Trays. Petro-SIM inserts the trays in the sequence you specified. All streams (except feeds) and auxiliary equipment below (or above, depending on the tray numbering scheme) the tray where you inserted is moved down (or up) by the number of trays that were inserted. You can also add and remove trays by specifying a new number of trays in the Current Number of Trays cell. When you add or delete trays in this way, all feeds remain connected to their current trays. This is the same as changing the number of theoretical trays on the Connections page. All inlet and outlet streams move appropriately. For example, if you change the number of trays from 10 to 20, a stream initially connected to tray 5 is now at tray 10 and a stream initially connected at stream 10 is now at tray 20. To remove trays from the Tray Section 1. On the Parameters page, click Customize. 2. In the Change Number of Trays view, enter the number of trays you want to remove in the Number of Trays to Add/Delete cell. 864 v Column Sub-flowsheet Environment 3. To specify which trays you want removed, select the first tray from the Tray to Add After or Delete First drop-down list. 4. Click Remove Trays. If you use the top-down numbering scheme, the specified number of trays below the first tray (including the first tray) are removed. If you use the bottom-up scheme, the specified number of trays above the first tray (including the first tray) are removed. Streams connected to a higher tray (numerically) are not affected. For example, if you delete three trays starting at tray number 6, a side draw initially at tray 5 remains there, but a side draw initially connected to tray 10 is now at tray 7. Any draw streams connected to trays 6, 7 or 8 are deleted only when you confirm the deletion. Pressures The Pressures page displays the pressure on each tray. When two pressures are known for the Tray Section, Petro-SIM interpolates to find the intermediate pressures. For example, if you enter the Condenser and Reboiler pressures, Petro-SIM calculates the top and bottom tray pressures based on the Condenser and Reboiler pressure drops. The intermediate tray pressures are then calculated by linear interpolation. You can also add User Variables and Notes. Rating The Tray Section Rating tab consists of these pages. v 865 Chapter 9: Separation Unit Operations Sizing The Sizing page provides Tray Section sizing information. From the Section Properties group, select one of these tray sizing options: Uniform Tray Data For uniform trays, select one of the following from the Internal Type group and specify the Tray Dimensions. When you are done setting the sizing parameters, optionally, check Size and Set Pressures to have Petro-SIM automatically re-size the remaining parameters and calculate the pressure profile based on the dimensions. Sieve 866 v Column Sub-flowsheet Environment Valve Bubble Cap Packed Select the Packing type from the drop-down list and specify the parameters. De-select Include Loading Regime Term to ?? v 867 Chapter 9: Separation Unit Operations Non--Uniform Tray Data Select the View Sizing Information: Trayed or Packed For each tray, specify the parameters in the grid. Nozzles Define the elevation of the Tray Section and the nozzle parameters. 868 v Column Sub-flowsheet Environment Heat Loss Select the Heat Flow Model.In the Detailed Properties area, enter the corresponding parameters in the grid. Petro-SIM calculates the Total Heat Flow based on the values you specify. Direct Q Simple v 869 Chapter 9: Separation Unit Operations Detailed In the Detailed Properties area, select the display option and then enter the corresponding parameters in the grid. Efficiencies In the Overall Tray Efficiencies group, select: l l 870 v Overall to specify overall efficiency values in the Efficiency column. Component to specify component-specific efficiencies. Column Sub-flowsheet Environment Pressure Drop Performance Tab The Tray Section Performance tab contains the following pages: Pressures The Pressures page displays the pressure for each tray. The table also includes the names of any inlet streams associated to a tray and the pressure for each inlet stream. v 871 Chapter 9: Separation Unit Operations Temperature The Temperature page displays the temperatures for each tray. The table also includes the names of any inlet streams associated to a tray and the temperature for each inlet stream. Flow The Flow page displays the liquid and vapour flow rates for each tray. The table also includes the names of any inlet streams associated to a tray and flow rate for each inlet stream. You can change the unit of the flow rates displayed by selecting the unit from the Flow Basis drop-down list: 872 v Column Sub-flowsheet Environment l l l l Molar Mass Standard Liquid Volume Actual Volume Summary The Summary page displays the flow rates, temperature, and pressure for each tray. Hydraulics This page is specific only to Dynamics. Refer to Hydraulics. Tee The Tee operation in the Column sub-flowsheet environment has the same pages and inherent functionality contained by the Tee in the Main environment with one addition, the Estimates page. For more information, refer to the Tee unit operation in the Main environment. 1. To add a Tee unit operation to the column, from the Column tab, select Tee. Optionally, press F12 and select Tee from the UnitOps view. v 873 Chapter 9: Separation Unit Operations A Tee unit operation is added to the column sub-flowsheet. 2. In the Tee property view, enter or view the properties on these tabs: l Design l Worksheet l Dynamics - This tab is available only when working in Dynamics mode. 3. To ignore the Tee during calculations, check Ignored. Design The Tee Design tab in the Column sub-flowsheet environment contains the same pages and functionality as a Tee unit operation in the Main environment, with one additional page, Estimates, described below. The Design tab is made up of these pages: Connections Refer to Connections page, Design tab in the Tee unit operation in the Main environment. Parameters Refer to Parameters page, Design tab in the Tee unit operation in the Main environment. Estimates On the Estimates page, you can help the convergence of the Column sub-flowsheet simultaneous solution by specifying flow estimates for the Tee product streams. Refer to General Features of the Solving Methods for information on which method supports the Tee operation. 874 v Column Sub-flowsheet Environment To specify flow estimates: 1. Select one of the Flow Basis options: Molar, Mass, or Volume. 2. Enter the Flow Estimate for the product streams in the cells next to the stream name. Click this... To... Update Replace all estimates except user specified estimates (in blue) with values obtained from the solution. Clear Selected Delete selected estimate. Clear Calculated Delete all calculated estimates. Clear All Delete all estimates. If the Tee operation is attached (using a draw stream) to the Column, one Tee Split Fraction Specification is added to the list of Column specifications for each Tee product stream that you specify. As you specify the split fractions for the product streams, these values are transferred to the individual Column specifications on the Monitor and Specs pages of the Column Property view. You can also add User Variables and Notes. v 875 Chapter 9: Separation Unit Operations Distillation Column Sub-flowsheet The Distillation Column Sub-flowsheet creates a Column with both a Reboiler and Condenser. The equipment and streams are a combination of the Reboiled Absorber and Refluxed Absorber unit operations. 1. To add a Distillation Column Sub-flowsheet to your simulation,from the Home tab, open the Operations, Separation palette (or press F4). 2. Double-click Distillation Column Sub-flowsheet (or drag it to the flowsheet). A Distillation Column unit operation is added to the active flowsheet and a new column sub-flowsheet is added to your current flowsheet. By default, Petro-SIM launches the column using an input expert (wizard) which guides you through the basic required parameters. You can disable the distillation column wizards in the Streams and Unit Ops page in your Preferences. De-select Use Wizards in the Distillation Columns group. If you disable the distillation column wizards, when you add a new column, the Column Property view is displayed where you can directly enter the properties for the column. Distillation Column Input Expert - page 1 Enter the feed and product streams (material or energy). The table below defines all the parameters on this page and identifies which are optional. 876 v Distillation Column Sub-flowsheet Use this... To... Column Name (optional) Modify the name of the column. Petro-SIM uses the default name specified for Column Operations in your Naming, Preferences page. Condenser Energy Stream Select a stream from the drop-down list or enter a name to define a new energy stream for the condenser. Condenser Select the condenser type: l l l Total Partial Full Rflx - Full Reflux Ovhd Vapour Outlet Select a stream from the drop-down list or enter a name to define a new Material Stream for the overhead vapour outlet. Not required for Total Condenser type. Ovhd Liquid Outlet Select a stream from the drop-down list or enter a name to define a new Material Stream for the overhead liquid outlet.Not required for Full Rflx Condenser type. Water Draw Check to enable the water stream, and then select a stream from the drop-down list or enter a name to define a new Material Stream for the water draw. Optional Side Draws (optional) For each side draw that you want to define: l In the Stream cell, select a stream from the drop-down list or enter a name to define a new Material Stream for the side draw. v 877 Chapter 9: Separation Unit Operations Use this... To... l l In the Type cell, select one of: L(iquid), V(apour), W(ater). In the Draw Stage cell, select the stage (tray) that the stream is coming off. Reboiler Energy Select a stream from the drop-down list or enter a name to define a new energy stream for the reboiler. Stream Bottoms Liquid Outlet Select a stream from the drop-down list or enter a name to define a new Material Stream for the bottoms liquid outlet. Reboiler Select the reboiler type: l l Stage Numbering Select: l l Inlet Steams Top Down Bottom Up You must define at least one inlet stream. For each stream that you want to define: l l #Stages Kettle Thermosyphon In the Stream cell, select a stream from the drop-down list or enter a name to define a new Material Stream for the inlet steam In the Inlet Stage cell, select the stage (tray) into which the stream is feeding. Enter the number of stages (trays) for the tray section. The default is set to 10. You must have at least 1 stage. The number of stages does not include the condenser and bottom reboiler. If side strippers are added to the Column, their stages are not included in this number. Petro-SIM initially treats the stages as being ideal. If you want your stages to be treated as real stages, you must specify efficiencies on the Efficiencies page of the Parameters tab. When you provide efficiencies for the stages, even if the value you specify is 1, Petro-SIM treats the stages as being real. Distillation Column Input Expert - page 2 Define the pressure settings for the condenser and reboiler. 878 v Distillation Column Sub-flowsheet Use this... To... Condenser Pressure Enter the condenser pressure and select the units from the drop-down list. Condenser Pressure Drop By default the value is set to zero. Optionally, enter a pressure drop value for the condenser. Reboiler Pressure Enter the reboiler pressure and select the units from the drop-down list. Distillation Column Input Expert - page 3 The parameters on this page are optional, but you can define the estimated temperature settings for the condenser, top stage and reboiler. v 879 Chapter 9: Separation Unit Operations Distillation Column Input Expert - page 4 The parameters on this page are optional, but you can define the flow basis and rates. 880 v Use this... To... Vapour Enter the vapour rate for the column. Not required for Total Condenser type. Liquid Rate Enter liquid rate for the column . Not required for Full Rflx condenser type. Distillation Column Sub-flowsheet Use this... To... Reflux Enter the reflux rate for the column. Not required for Full Rflx condenser type. Flow Basis Select the flow basis for the flow rates: Molar, Mass, or Volume. Optionally, click Side Ops to open the Side Operations Input Expert which guides you through defining the Side Ops for the column. 3. When you are finished, click Done. A Distillation Column is added to the flowsheet. Distillation Column in the PFD Petro-SIM also provides additional prebuilt distillation columns that can be accessed from the UnitOps view. Press F12. In the UnitOps view, select Prebuilt Columns and then choose the column type that you want to add to your simulation. l l l l 3 Stripper Crude - a distillation column with predefined inlet and outlet streams, 3 side strippers, pumparounds, and side draws. 4 Stripper Crude - a distillation column with predefined inlet and outlet streams, 4 side strippers, pumparounds, and side draws. FCCU Main Fractionator - a distillation column with predefined inlet and outlet streams, side strippers, pumparounds, and side draws. Vacuum Resid Tower - a distillation column with predefined inlet and outlet streams, pumparounds, and side draws. After installing a column, using an Input Expert or directly from the UnitOps view, the Column Property view is displayed where you can view or enter properties in these tabs: v 881 Chapter 9: Separation Unit Operations l l l l l l l l 882 v Design Parameters Side Ops Rating tab Performance Flowsheet Reactions Distop Refluxed Absorber Column Sub-flowsheet Refluxed Absorber Column Sub-flowsheet The Refluxed Absorber Column Sub-flowsheet contains a tray section and an overhead condenser (partial or total). Additional material streams associated with the condenser are also added. For example, the vapour entering the condenser from the top tray is named to condenser by default and the liquid returning to the tray section is the reflux. When you install a Refluxed Absorber Column, you are adding only a Condenser to the tray section. Specifying a partial condenser increases the number of required specifications by two. The default specifications are the overhead vapour flow rate and the side liquid (Distillate) draw. Specifying a total condenser results in only one available specification since there is no overhead vapour product. Either of the overhead vapour or distillate flow rates can be specified as zero, which creates three possible combinations for these two specifications. Each combination defines a different set of operating conditions. The three possible Refluxed Absorber Column configurations are: l l l Partial condenser with vapour overhead but no side liquid (distillate draw) Partial condenser with both vapour overhead and distillate draws Total condenser with distillate but no vapour overhead draw 1. To add a Refluxed Absorber Column Sub-flowsheet to your simulation,from the Home tab, open the Operations, Separation palette (or press F4). 2. Double-click flowsheet). Refluxed Absorber Column Sub-flowsheet (or drag it to the A Refluxed Absorber Column unit operation is added to the active flowsheet and a new column sub-flowsheet is added to your current flowsheet. By default, Petro-SIM launches the column using an input expert (wizard) which guides you through the basic required parameters. You can disable the distillation column wizards in the Streams and Unit Ops page in your Preferences. De-select Use Wizards in the Distillation Columns group. If you disable the distillation column wizards, when you add a new column, the Column Property view is displayed where you can directly enter the properties for the column. v 883 Chapter 9: Separation Unit Operations Refluxed Absorber Column Input Expert - page 1 Enter the feed and product streams (material or energy). The table below defines all the parameters on this page and identifies which are optional. Use this... To... Column Name (optional) Modify the name of the column. Petro-SIM uses the default name specified for Column Operations in your Naming, Preferences page. Condenser Energy Stream Select a stream from the drop-down list or enter a name to define a new energy stream for the condenser. Condenser Select the condenser type: l l l 884 v Total Partial Full Rflx - Full Reflux Ovhd Outlets Required only when Partial Condenser is selected. Select the streams from the drop-down lists or enter a names to define new Material Streams for the overhead outlets Ovhd Vapour Outlet Select a stream from the drop-down list or enter a name to define a new Material Stream for the overhead vapour outlet. Not required for Total Condenser type. Ovhd Liquid Outlet Select a stream from the drop-down list or enter a name to define a new Material Stream for the overhead liquid outlet.Not required for Full Rflx Condenser type. Water Draw Check to enable the water stream, and then select a stream from the dropdown list or enter a name to define a new Material Stream for the water Refluxed Absorber Column Sub-flowsheet Use this... To... draw. Not available for Total or Full Rflx Condenser types. Optional Side Draws (optional) For each side draw that you want to define: l l l In the Stream cell, select a stream from the drop-down list or enter a name to define a new Material Stream for the side draw. In the Type cell, select one of: L(iquid), V(apour), W(ater). In the Draw Stage cell, select the stage (tray) that the stream is coming off. Bottoms Liquid Outlet Select a stream from the drop-down list or enter a name to define a new Material Stream for the bottoms liquid outlet. Stage Numbering Select: l l Top Down Bottom Up Bottom Stage Inlet Select a stream from the drop-down list or enter a name to define a new Material Stream for the vapour or 2-phase inlet to the bottom of the column. Optional Inlet Steams (optional) For each stream that you want to define: l l #Stages In the Stream cell, select a stream from the drop-down list or enter a name to define a new Material Stream for the inlet steam In the Inlet Stage cell, select the stage (tray) into which the stream is feeding. Enter the number of stages (trays) for the tray section. The default is set to 10. You must have at least 1 stage. The number of stages does not include the condenser. If side strippers are added to the Column, their stages are not included in this number. Petro-SIM initially treats the stages as being ideal. If you want your stages to be treated as real stages, you must specify efficiencies on the Efficiencies page of the Parameters tab. When you provide efficiencies for the stages, even if the value you specify is 1, Petro-SIM treats the stages as being real. Refluxed Absorber Column Input Expert - page 2 Define the pressure settings for the condenser and bottom stage. v 885 Chapter 9: Separation Unit Operations Use this... To... Condenser Pressure Enter the condenser pressure and select the units from the drop-down list. Condenser Pressure Drop By default the value is set to zero. Optionally, enter a pressure drop value for the condenser. Bottom Stage Pressure Enter the bottom stage pressure and select the units from the drop-down list. Refluxed Absorber Column Input Expert - page 3 The parameters on this page are optional, but you can define the estimated temperature settings for the condenser and the top and bottom stages. 886 v Refluxed Absorber Column Sub-flowsheet Refluxed Absorber Column Input Expert - page 4 The parameters on this page are optional, but you can define the pump-aroun specifications. Use this... To... Vapour Rate Enter the vapour rate for the column. Not required for Total Condenser type. Liquid Rate Enter liquid rate for the column . Not required for Full Rflx condenser type. Reflux Ratio Enter the reflux rate for the column. Not required for Full Rflx condenser type. Flow Basis Select the flow basis for the flow rates: Molar, Mass, or Volume. Optionally, click Side Ops to open the Side Operations Input Expert which guides you through defining the Side Ops for the column. 3. When you are finished, click Done. A Refluxed Absorber Column is added to the flowsheet. v 887 Chapter 9: Separation Unit Operations Refluxed Absorber Column in the PFD 4. In the Column Property view that is displayed, you can view or enter properties in these tabs: l Design l Parameters l Side Ops l Rating tab l Performance l Flowsheet l Reactions l Distop 888 v Reboiled Absorber Column Sub-flowsheet Reboiled Absorber Column Sub-flowsheet The Reboiled Absorber Column consists of a tray section and a bottom reboiler. Two additional streams connecting the reboiler to the tray section are also included. When you install a reboiled absorber (i.e., add only a reboiler to the tray section), you increase the number of required specifications by one over the basecase. As there is no overhead liquid, the default specification in this case is the overhead vapour flow rate. 1. To add a Reboiled Absorber Column Sub-flowsheet to your simulation,from the Home tab, open the Operations, Separation palette (or press F4). 2. Double-click flowsheet). Reboiled Absorber Column Sub-flowsheet (or drag it to the A Reboiled Absorber Column unit operation is added to the active flowsheet and a new column sub-flowsheet is added to your current flowsheet. By default, Petro-SIM launches the column using an input expert (wizard) which guides you through the basic required parameters. You can disable the distillation column wizards in the Streams and Unit Ops page in your Preferences. De-select Use Wizards in the Distillation Columns group. If you disable the distillation column wizards, when you add a new column, the Column Property view is displayed where you can directly enter the properties for the column. Reboiled Absorber Column Input Expert - page 1 Enter the feed and product streams (material or energy). The table below defines all the parameters on this page and identifies which are optional. v 889 Chapter 9: Separation Unit Operations Use this... To... Column Name (optional) Modify the name of the column. Petro-SIM uses the default name specified for Column Operations in your Naming, Preferences page. Ovhd Vapour Outlet Select a stream from the drop-down list or enter a name to define a new Material Stream for the overhead vapour outlet. Top Stg. Reflux Select the top stage reflux type: l l Optional Side Draws (optional) For each side draw that you want to define: l l l In the Stream cell, select a stream from the drop-down list or enter a name to define a new Material Stream for the side draw. In the Type cell, select one of: L(iquid), V(apour), W(ater). In the Draw Stage cell, select the stage (tray) that the stream is coming off. Reboiler Energy Stream Select a stream from the drop-down list or enter a name to define a new energy stream for the reboiler. Bottoms Liquid Outlet Select a stream from the drop-down list or enter a name to define a new Material Stream for the bottoms liquid outlet. Reboiler Select the reboiler type: l 890 v Liquid Inlet Pump-around - If selected, a stream from the drop-down list or enter a name to define a new Material Stream for the PA Draw Stage. Kettle Reboiled Absorber Column Sub-flowsheet Use this... To... l Stage Numbering Select: l l Inlet Steams Top Down Bottom Up You must define at least one inlet stream. For each stream that you want to define: l l #Stages Thermosyphon In the Stream cell, select a stream from the drop-down list or enter a name to define a new Material Stream for the inlet steam In the Inlet Stage cell, select the stage (tray) into which the stream is feeding. Enter the number of stages (trays) for the tray section. The default is set to 10. You must have at least 1 stage. The number of stages does not include the reboiler. If side strippers are added to the Column, their stages are not included in this number. Petro-SIM initially treats the stages as being ideal. If you want your stages to be treated as real stages, you must specify efficiencies on the Efficiencies page of the Parameters tab. When you provide efficiencies for the stages, even if the value you specify is 1, Petro-SIM treats the stages as being real. Reboiled Absorber Column Input Expert - page 2 Define the pressure settings for the top stage and reboiler. v 891 Chapter 9: Separation Unit Operations Use this... To... Top Stage Pressure Enter the top stage pressure and select the units from the drop-down list. Reboiler Pressure Enter the reboiler pressure and select the units from the drop-down list. Cooler dP By default the value is set to zero. Optionally, enter a pressure drop value for the pump-around cooler. Reboiled Absorber Column Input Expert - page 3 The parameters on this page are optional, but you can define the estimated temperature settings for the top stage and reboiler. 892 v Reboiled Absorber Column Sub-flowsheet Reboiled Absorber Column Input Expert - page 4 The parameters on this page are optional, but you can define the flow basis and rates. Use this... To... Flow Basis Enter the flow basis for the pump-around. PA Rate Enter pump-around rate. 2nd Spec Type Select the type of the second pump-around: l dT v 893 Chapter 9: Separation Unit Operations Use this... To... l l l Return T Duty Return VF 2nd Spec Value Enter the value for the second pump-around. Boil-up Enter the ratio for the boil-up. Optionally, click Side Ops to open the Side Operations Input Expert which guides you through defining the Side Ops for the column. 3. When you are finished, click Done. A Reboiled Absorber Column is added to the flowsheet. Reboiled Absorber Column in the PFD 4. In the Column Property view that is displayed, you can view or enter properties in these tabs: l Design l Parameters l Side Ops l Rating tab l Performance l Flowsheet l Reactions l Distop 894 v Absorber Column Sub-flowsheet Absorber Column Sub-flowsheet The Absorber Column contains a only a tray section and the only streams are the overhead vapour and bottom liquid products. The conditions and composition of the Column feed stream, as well as the operating pressure, define the resulting converged solution. The converged solution includes the conditions and composition of the vapour and liquid product streams. 1. To add an Absorber Column Sub-flowsheet to your simulation,from the Home tab, open the Operations, Separation palette (or press F4). 2. Double-click Absorber Column Sub-flowsheet (or drag it to the flowsheet). A Absorber Column unit operation is added to the active flowsheet and a new column sub-flowsheet is added to your current flowsheet. By default, Petro-SIM launches the column using an input expert (wizard) which guides you through the basic required parameters. You can disable the distillation column wizards in the Streams and Unit Ops page in your Preferences. De-select Use Wizards in the Distillation Columns group. If you disable the distillation column wizards, when you add a new column, the Column Property view is displayed where you can directly enter the properties for the column. Absorber Column Input Expert - page 1 Enter the feed and product streams (material or energy). The table below defines all the parameters on this page and identifies which are optional. v 895 Chapter 9: Separation Unit Operations Use this... To... Column Name (optional) Modify the name of the column. Petro-SIM uses the default name specified for Column Operations in your Naming, Preferences page. Ovhd Vapour Outlet Select a stream from the drop-down list or enter a name to define a new Material Stream for the overhead vapour outlet. Top Stg. Reflux Select the top stage reflux type: l l Optional Side Draws (optional) For each side draw that you want to define: l l l In the Stream cell, select a stream from the drop-down list or enter a name to define a new Material Stream for the side draw. In the Type cell, select one of: L(iquid), V(apour), W(ater). In the Draw Stage cell, select the stage (tray) that the stream is coming off. Bottoms Liquid Outlet Select a stream from the drop-down list or enter a name to define a new Material Stream for the bottoms liquid outlet. Stage Numbering Select: l l 896 v Liquid Inlet Pump-around - If selected, a stream from the drop-down list or enter a name to define a new Material Stream for the PA Draw Stage. Top Down Bottom Up Bottom Stage Inlet Select a stream from the drop-down list or enter a name to define a new Material Stream for the bottom stage inlet. Optional Inlet (optional) For each stream that you want to define: Absorber Column Sub-flowsheet Use this... Steams To... l l #Stages In the Stream cell, select a stream from the drop-down list or enter a name to define a new Material Stream for the inlet steam In the Inlet Stage cell, select the stage (tray) into which the stream is feeding. Enter the number of stages (trays) for the tray section. The default is set to 10. You must have at least 1 stage.If side strippers are added to the Column, their stages are not included in this number. Petro-SIM initially treats the stages as being ideal. If you want your stages to be treated as real stages, you must specify efficiencies on the Efficiencies page of the Parameters tab. When you provide efficiencies for the stages, even if the value you specify is 1, Petro-SIM treats the stages as being real. Absorber Column Input Expert - page 2 Define the pressure settings for the top and bottom stages. Use this... To... Top Stage Pressure Enter the top stage pressure and select the units from the drop-down list. Bottom Stage Pressure Enter the bottom stage pressure and select the units from the dropdown list Absorber Column Input Expert - page 3 The parameters on this page are optional, but you can define the estimated temperature v 897 Chapter 9: Separation Unit Operations settings for the top and bottom stages. Optionally, click Side Ops to open the Side Operations Input Expert which guides you through defining the Side Ops for the column. 3. When you are finished, click Done. An Absorber Column is added to the flowsheet. Absorber Column in the PFD 4. In the Column Property view that is displayed, you can view or enter properties in these tabs: l Design l Parameters l Side Ops l Rating tab l Performance l Flowsheet l Reactions l Distop 898 v Liquid-Liquid Extractor Liquid-Liquid Extractor The Liquid-Liquid Extractor creates a simplified column sub-flowsheet that is used for liquidliquid extractions. 1. To add a Liquid-Liquid Extractor Sub-flowsheet to your simulation,from the Home tab, open the Operations, Separation palette (or press F4). 2. Double-click Liquid-Liquid Extractor (or drag it to the flowsheet). A Liquid-Liquid Extractor unit operation is added to the active flowsheet and a new column sub-flowsheet is added to your current flowsheet. By default, Petro-SIM launches the column using an input expert (wizard) which guides you through the basic required parameters. You can disable the distillation column wizards in the Streams and Unit Ops page in your Preferences. De-select Use Wizards in the Distillation Columns group. If you disable the distillation column wizards, when you add a new column, the Column Property view is displayed where you can directly enter the properties for the column. Liquid-Liquid Extractor Input Expert - page 1 Enter the feed and product streams (material or energy). The table below defines all the parameters on this page and identifies which are optional. v 899 Chapter 9: Separation Unit Operations Use this... To... Column Name (optional) Modify the name of the column. Petro-SIM uses the default name specified for Column Operations in your Naming, Preferences page. Ovhd Light Liquid Select a stream from the drop-down list or enter a name to define a new Material Stream for the overhead light liquid. Optional Side Draws (optional) For each side draw that you want to define: l l l In the Stream cell, select a stream from the drop-down list or enter a name to define a new Material Stream for the side draw. In the Type cell, select one of: L(iquid), V(apour), W(ater). In the Draw Stage cell, select the stage (tray) that the stream is coming off. Bottoms Heavy Liquid Select a stream from the drop-down list or enter a name to define a new Material Stream for the bottoms heavy liquid. Stage Numbering Select: l l Top Down Bottom Up Bottom Stage Inlet Select a stream from the drop-down list or enter a name to define a new Material Stream for the bottom stage inlet. Optional Inlet Steams (optional) For each stream that you want to define: l l In the Stream cell, select a stream from the drop-down list or enter a name to define a new Material Stream for the inlet steam In the Inlet Stage cell, select the stage (tray) into which the stream is feeding. Top Stage Inlet Select a stream from the drop-down list or enter a name to define a new Material Stream for the top stage inlet. #Stages Enter the number of stages (trays) for the tray section. The default is set to 10. You must have at least 1 stage. The number of stages does not include the condenser and bottom reboiler. If side strippers are added to the Column, their stages are not included in this number. Petro-SIM initially treats the stages as being ideal. If you want your stages to be treated as real stages, you must specify efficiencies on the Efficiencies page of the Parameters tab. When you provide efficiencies for the stages, even if the value you specify is 1, Petro-SIM treats the stages as being real. 900 v Liquid-Liquid Extractor Liquid-Liquid Extractor Input Expert - page 2 Define the pressure settings for the top and bottom stages. Use this... To... Top Stage Pressure Enter the top stage pressure and select the units from the drop-down list. Bottom Stage Pressure Enter the bottom stage pressure and select the units from the dropdown list. Liquid-Liquid Extractor Input Expert - page 3 The parameters on this page are optional, but you can define the estimated temperature settings for the top and bottom stages. When you are finished, click Done. A Liquid-Liquid Extractor is added to the flowsheet. v 901 Chapter 9: Separation Unit Operations Liquid-Liquid Extractor in the PFD The Column Property view is displayed where you can view or enter properties in these tabs: l l l l l l l l 902 v Design Parameters Side Ops Rating tab Performance Flowsheet Reactions Distop Three Phase Distillation Three Phase Distillation For non-ideal systems with more than two components, boundaries can exist in the form of azeotropes, which a simple distillation system cannot cross. The formation of azeotropes in a 3-phase system provides a thermodynamic barrier to separating chemical mixtures. Distillation schemes for non-ideal systems are often difficult to converge without accurate initial guesses. To aid in the initialization of columns, you can use the 3-phase input expert to initialize temperatures, flows and compositions. The key difference between using the standard Column unit operations and their 3-phase counterparts lies in the solver that is used. The default solver for 3-phase Columns is the sparse continuation solver which is an advanced solver designed to handle 3-phase, non-ideal chemical systems that other solvers cannot handle. 1. To add a Three Phase Distillation Column Sub-flowsheet to your simulation,from the Home tab, open the Operations, Separation palette (or press F4). 2. Double-click Three Phase Distillation (or drag it to the flowsheet). 3. In the Three Phase Column Input Expert, select the 3-phase column type that you want to install: l Distillation l Refluxed Absorber l Reboiled Absorber l Absorber Each selection opens the Three Phase Input Expert that guides you through the preliminary data required to build the 3-phase unit operation: v 903 Chapter 9: Separation Unit Operations If you disable the distillation column wizards in your Preferences, when you add a new column, installing a Three Phase column opens the Column Property view for a basic Distillation column. When your Column converges, Petro-SIM automatically performs a 3-phase flash on the top stage. The Trace window displays Column convergence messages. l l If a second liquid phase is detected and no associated water draw is found, a warning message displays. If there is a water draw, Petro-SIM checks the next stage for a second liquid phase, with the same results as above. This continues down the column until a stage is found that is 2phase only. Any 3-phase stages below the 2-phase stage are not detected because the checking would have ended in the 2-phase stage. Petro-SIM always indicates the existence of the second liquid phase. This continues until the Column reverts to VLE operation, or all applicable stages have water draws placed on them. Three Phase Distillation Column Refer to Distillation Column Sub-flowsheet for more details about this type of column. 1. On page 1 of the Three Phase Column Input Expert, enter the Number of Stages for the column and select the Stage Numbering: Top Down or Bottom Up. 2. In the Two Liquid Phase Check grid, check the stages that you want to send the composition to the flash calculations. 904 v Three Phase Distillation Any 3-phase stages below a 2-phase stage are not detected because the checking ends in the 2-phase stage. 3. Click Next. 4. On page 2, define the Condenser specifications. Select: l Condenser Type - Total, Partial, or Full Reflux l Outlet Streams - Light, Heavy, or Both l Reflux Streams - Light, Heavy, or Both 5. Select a stream from the drop-down list or enter a name to define a new stream for the Condenser (energy), outlet and reflux (material) streams. 6. Click Next. 7. On page 3, optionally, define the vapour liquid,and reflux flows, rates, and fractions. The Degrees of Freedom displays the required number of parameters. v 905 Chapter 9: Separation Unit Operations 8. Click Next. The Distillation Column Sub-flowsheet input expert guides you through the remaining data required as for a 2-phase distillation column. 3-Phase Distillation Column in the PFD When you are done, you can view or enter additional properties in the Column Property View. Three Phase Refluxed Absorber Column Refer to Refluxed Absorber Column Sub-flowsheet for more details about this type of column. 906 v Three Phase Distillation 1. On page 1 of the Three Phase Column Input Expert, enter the Number of Stages for the column and select the Stage Numbering: Top Down or Bottom Up. 2. In the Two Liquid Phase Check grid, check the stages that you want to send the composition to the flash calculations. Any 3-phase stages below a 2-phase stage are not detected because the checking ends in the 2-phase stage. 3. Click Next. 4. On page 2, define the Condenser specifications. Select: l Condenser Type - Total, Partial, or Full Reflux l Outlet Streams - Light, Heavy, or Both l Reflux Streams - Light, Heavy, or Both v 907 Chapter 9: Separation Unit Operations 5. Select a stream from the drop-down list or enter a name to define a new stream for the Condenser (energy), outlet, and reflux (material) streams. 6. Click Next. 7. On page 3, optionally, define the vapour liquid,and reflux flows, rates, and fractions. The Degrees of Freedom displays the required number of parameters. 8. Click Next. The Refluxed Absorber Column Sub-flowsheet input expert guides you through the remaining data required as for a standard 2-phase distillation column. 9. When you are done, you can view or enter additional properties in the Column Property View. Three Phase Reboiled Absorber Column Refer to Reboiled Absorber Column Sub-flowsheet for more details about this type of column. 1. On page 1 of the Three Phase Column Input Expert, enter the Number of Stages for the column and select the Stage Numbering: Top Down or Bottom Up. 2. In the Two Liquid Phase Check grid, check the stages that you want to send the composition to the flash calculations. 908 v Three Phase Distillation Any 3-phase stages below a 2-phase stage are not detected because the checking ends in the 2-phase stage. 3. Click Next. The Reboiled Absorber Column Sub-flowsheet input expert guides you through the remaining data required as for a 2-phase distillation column. When you are done, you can view or enter additional properties in the Column Property View. Three Phase Absorber Column Refer to Absorber Column Sub-flowsheet for more details about this type of column. 1. On page 1 of the Three Phase Column Input Expert, enter the Number of Stages for the column and select the Stage Numbering: Top Down or Bottom Up. 2. In the Two Liquid Phase Check grid, check the stages that you want to send the composition to the flash calculations v 909 Chapter 9: Separation Unit Operations Any 3-phase stages below a 2-phase stage are not detected because the checking ends in the 2-phase stage. 3. Click Next. The Absorber Column Sub-flowsheet input expert guides you through the remaining data required as for a 2-phase distillation column. When you are done, you can view or enter additional properties in the Column Property View. 910 v Custom Column Sub-flowsheet Custom Column Sub-flowsheet Petro-SIM allows you to simulate complex custom column and multiple column scan within a single sub-flowsheet using various combinations of sub-flowsheet operations . You have a great deal of freedom when defining column configurations, which can be set up with varying degrees of complexity. You can use a wide array of Column operations in a manner that is straightforward and flexible. Custom Column configurations can be stored as templates that can be called into other simulations. 1. To add a Custom Column Sub-Flowsheet operation to your simulation, from the Home tab, open the Operations, Separation palette (or press F4). 2. Double-click Custom column (or drag it to the flowsheet). 3. In the Column Flowsheet Option view, select one of the following options to create a new column sub-flowsheet in your simulation: Read an Existing Column Template In the Available Column Templates view, select the column template (*.col) that you want to use. Depending on the type of column you select, the Column Property View or one of the column Input Experts will guide you through installing a new column. Start with a Blank Flowsheet When you select Start with a Blank Flowsheet, Petro-SIM adds a column subflowsheet operation containing no unit operations or streams to the PFD. Begin with the Column Property View to define the column. Read a User Created Column Template In the Available Column Templates view, navigate to and select the template for the v 911 Chapter 9: Separation Unit Operations column sub-flowsheet that you want to use. 4. The Column property view is used to define specifications, provide estimates, monitor convergence, view stage-by-stage and product stream summaries, add pumparounds and side-strippers, specify dynamic parameters, define convergence tolerances, and attach reactions to Column stages. Use these tabs in the Column property view to set or modify the properties for the column: l l l l l l l l l Design Parameters Side Ops Rating tab Worksheet Performance Flowsheet Reactions Distop 5. Click the Run button to start the convergence algorithm. Use the Reset button to reset the Column. Petro-SIM first performs iterations toward convergence of the inner and outer loops (Equilibrium and Heat/Spec Errors) and then checks the individual specification tolerances. The Monitor page displays a summary of the convergence procedure for the equilibrium and Heat/Spec Errors. 912 v Column Property View Column Property View The Column Property view, the representation of the Column in the main (Parent) flowsheet, provides access to the Column where you can define specifications, provide estimates, monitor convergence, view stage-by-stage and product stream summaries, add pumparounds and sidestrippers, specify dynamic parameters, define convergence tolerances, and attach reactions to Column stages. The first step in installing a Column is deciding which type you want to install. Your choice depends on the type of equipment (for example, reboilers and condensers) your Column requires. Petro-SIM has several pre-constructed Column configurations that can be used for installing a new Column. In addition, you can also install several other prebuilt columns by selecting a template or install a custom column. Refer also to Design Tips for Reactive Distillation for details about designing a reactive distillation Column. 1. To add a Column Sub-flowsheet to your simulation,from the Home tab, open the Operations, Separation palette (or press F4). 2. Choose one of the following column icons from the palette. Input experts that guide you through the installation are available for the first six basic Column types: Select this... Palette To define this type of column... Icon Distillation Column Tray section with both a reboiler and condenser. Refluxed Absorber Column Tray section and an overhead condenser. Reboiled Absorber Column Tray section and a bottom stage reboiler. Absorber Column Tray section only. Use to define vapour-gas systems. Liquid-Liquid Extractor Tray section only. Use to define liquid-liquid systems. Three Phase Distillation Tray section, three-phase condenser, reboiler. Condenser can be either chemical or hydrocarbon specific. Uses an advanced solver v 913 Chapter 9: Separation Unit Operations Select this... Palette To define this type of column... Icon designed to handle Three Phase, non-ideal chemical systems that other solvers cannot handle. Custom Column Define a column using your own specifications. This column type does not have an input expert. 3. After installing a column, using an Input Expert or directly from the UnitOps view, the Column Property view is displayed where you can view or enter properties in these tabs: l l l l l l l l l Design Parameters Side Ops Rating Worksheet Performance Flowsheet Reactions Distop 4. Click Run to run the convergence algorithm. You can run the Column from the Parent flowsheet or from the Column sub-flowsheet. 5. Click Reset to reset the Column. 6. De-select Update Outlets to stops the results from propagating out of the sub-flowsheet. It is checked by default. 7. To ignore the Column during calculations, check Ignored. Petro-SIM Columns Multi-stage fractionation towers, such as crude and vacuum distillation units, reboiled demethanizers, and extractive distillation Columns, are some of the most complex unit operations that Petro-SIM simulates. Refer to Prebuilt Column Templates for details on installing a column in your simulation. Depending on the system being simulated, each of these towers consists of a series of equilibrium or non-equilibrium flash stages. The vapour leaving each stage flows to the stage above and the liquid from the stage flows to the stage below. A stage can have one or more feed streams flowing onto it, liquid or vapour products withdrawn from it, and can be heated or cooled with a side exchanger. 914 v Column Property View The following figure shows a typical stage j in a Column using the top-down stage numbering scheme. The stage above is j-1, while the stage below is j+1. Stream Nomenclature: F = Stage feed stream L = Liquid stream travelling to stage below V = Vapour stream travelling to stage above LSD = Liquid side draw VSD = Vapour side draw from stage Q = Energy stream entering stage More complex towers can have pumparounds, which withdraw liquid from one stage of the tower and typically return it to a stage further up the Column. Small auxiliary towers, called side strippers, can be used on some towers to help purify side liquid products. Virtually any type of Column can be simulated with the appropriate combination of features. It is important to note that the Column operation by itself is capable of handling all the different fractionation applications. Petro-SIM has the ability to run cryogenic towers, high-pressure TEG absorption systems, sour water strippers, lean oil absorbers, complex crude towers, highly nonideal azeotropic distillation Columns, etc. There are no limits for the number of components and stages. The size of the Column that you can solve depends on your hardware configuration and the amount of computer memory you have available. The Column is unique among the unit operations in the methods used for calculations. There are several additional underlying equations that are used in the Column. The Francis Weir equation is the starting point for calculating the liquid flow rate leaving a tray: LN = Cρlw h 1.5 here: v 915 Chapter 9: Separation Unit Operations L = liquid flow rate leaving tray N L = liquid flow rate leaving tray N C = units conversion constant ρ = density of liquid on tray l = weir length w h = height of liquid above weir The vapour flow rate leaving a tray is determined by the resistance equation: Fvap = k ∆P friction where: F vap = vapour flow rate leaving tray N k = conductance, which is a constant representing the reciprocal of resistance to flow For Columns the conductance, k, is proportional to the square of the Column diameter. ΔP friction = dry hole pressure drop The pressure drop across a stage is determined by summing the static head and the frictional losses. It is possible to use Column stage efficiencies when running a Column in dynamics. The efficiency is equivalent to bypassing a portion of the vapour around the liquid phase where n is the specified efficiency. 916 v Column Property View Petro-SIM can model both weeping and flooding inside the Column. If ΔP is very small, the friction stage exhibits weeping. Therefore, it is possible to have a liquid flow to the stage below even if the liquid height over the weir is zero. To install a column in your simulation, refer to Column Property View or Prebuilt Column Templates. Prebuilt Column Templates Petro-SIM contains a number of Column templates that were designed to simplify installing Column sub-flowsheets in your simulations. A Column template (*.col) is a pre-constructed configuration or blueprint of a common type of Column that contains the unit operations and streams that are necessary for defining the particular Column type, as well as a default set of specifications. v 917 Chapter 9: Separation Unit Operations 1. To view all available Petro-SIM Column templates, press F12 to open the UnitOps view. 2. Select Prebuilt Columns. 3. Select the template that closely matches the Column configuration that you want to install. 4. Provide the necessary input in the Input Expert view (if applicable) or enter/modify the column specifications in the Column Property view. Refer also to these column unit operations: l l l l l l l Distillation Column Sub-flowsheet Refluxed Absorber Column Sub-flowsheet Reboiled Absorber Column Sub-flowsheet Absorber Column Sub-flowsheet Liquid-Liquid Extractor Three-Phase Distillation Custom Column Sub-flowsheet Default Replaceable Specifications Specifications are the values that the Column convergence algorithm is trying to meet. When you select a particular Column template, or as you add side equipment, Petro-SIM creates default specifications. You can use the specifications that Petro-SIM provides, or replace these specifications with others more suited to your requirements. The available default replaceable specifications are dependent on the Basic Column type (template) that you chose. 918 v Column Property View The pressure for a tray section stage, condenser or reboiler can be specified at any time on the Profiles page of the Column property view. The default specifications for the four basic Column templates are combinations of the following: l l l l l Overhead vapour flow rate Distillate flow rate Bottoms flow rate Reflux ratio Reflux rate The provided templates contain only pre-named internal streams (streams which are both a feed and product). For instance, the Reflux stream, which is named by Petro-SIM, is a product from the condenser and a feed to the top tray of the tray section. Specifications can be set as specifications or changed to estimates. Refer to the Monitor and Specs pages for more information. In the following schematics, you specify the feed and product streams, including duty streams. Petro-SIM Column Conventions Column tray sections, overhead condensers and bottom reboilers are each defined as individual unit operations. By making the individual components of the Column separate pieces of equipment, access to equipment information and the streams connecting them is easier. Condensers and reboilers are not numbered stages as they are considered to be separate from the tray section. The following table describes the conventions, definitions, and descriptions of the basic Columns Column Component Description Tray Section A Petro-SIM unit operation that represents the series of equilibrium trays in a Column. Stages Stages are numbered from the top down or from the bottom up, depending on your preference. The top tray is 1, and the bottom tray is N for the top-down numbering scheme. The stage numbering preference can be selected on the v 919 Chapter 9: Separation Unit Operations Column Component Description Connections page. Overhead Vapour Product The overhead vapour product is the vapour leaving the top tray of the tray section in simple absorbers and reboiled absorbers. In refluxed absorbers and distillation towers, the overhead vapour product is the vapour leaving the condenser. Overhead Liquid The overhead liquid product is the distillate leaving the condenser in refluxed Product absorbers and distillation towers. There is no top liquid product in simple absorbers and reboiled absorbers. Bottom Liquid Product The bottom liquid product is the liquid leaving the bottom tray of the tray section in simple absorbers and refluxed absorbers. In reboiled absorbers and distillation Columns, the bottom liquid product is the liquid leaving the reboiler. Overhead Condenser An overhead condenser represents a combined Cooler and separation stage and is not given a stage number. Bottom reboiler A bottom reboiler represents a combined heater and separation stage and is not given a stage number. Mixing Rules at Feed Stages When a feed stream is introduced onto a stage of the Column, the following sequence is used to establish the resulting internal product streams: 1. The entire component flow (liquid and vapour phase) of the feed stream is added to the component flows of the internal vapour and liquid phases entering the stage. 2. The total enthalpy (vapour and liquid phases) of the feed stream is added to the enthalpies of the internal vapour and liquid streams entering the stage. 3. Petro-SIM flashes the combined mixture based on the total enthalpy at the stage Pressure. The results of this process produce the conditions and composition of the vapour and liquid phases leaving the stage. In most physical situations, the vapour phase of a feed stream does not come in close contact with the liquid on its feed stage. If this is the case, the Column allows you to split all material inlet streams into their phase components before being fed to the Column. The Split Inlets check box can be activated in the Setup page of the Flowsheet tab. You can also set all the feed streams in a Column to always split by the option in the Streams and Unit Ops page, on the Simulation tab in your Preferences. 920 v Column Property View Heat Integration (Pre-heat Train) A distillation column can have pumparounds that exchange heat with other process streams and some of these streams can impact or be a column feed. What is the best way to model this situation? It is possible to model a larger portion of the flowsheet inside the column environment, but this easily gets complicated and can be hard to solve reliably. There are different methods for modelling the pre-heat train and each one fulfils a different need depending on what you are trying to achieve with your simulation. Petro-SIM supports the following approaches (listed from least to most rigorous). Connecting by Simple Duties This method models both sides of the process separately, with heaters on one side and coolers on the other (one side being inside the column flowsheet and the other being in another flowsheet). The unit operations are connected by duty streams and or spreadsheets. You essentially specify temperatures on one side of the process and the duty being calculated is transferred to the other side of the process. Exit temperatures are calculated for you. This is a very basic way of connecting, but might suffice if you are controlling temperatures on one side and want to see the effect on the other side. This can be easy to solve because it is basically an unconnected set of processes, but it can also give you errors that might not be apparent on first view. A calculated duty could be impossible to achieve in a heat exchange unit that a heater/cooler pair would quite happily solve to. Exporting Pumparounds from the Column This level of rigour lets the column calculate the inlet and exit conditions of the process streams in the pumparounds, which you are then free to connect to a set of heat exchangers to use in the pre-heat calculations. This is typically done when you are looking at utility-driven heat exchangers in the pumparounds. You can easily put a disconnected set of utility streams attached to the pumparound and then let the column calculate the inlet and outlet conditions of that pumparound. The exchanger will then calculate the duty required. This method is more difficult to fully connect as a pre-heat train because the column calculates both inlets and outlets, so having a pre-heat train calculate the feed to the column from both the inlet and outlet conditions of the pumparounds can lead to column and recycle loops that will never converge. Moving the Pumparounds Outside of the Column and Solving the Preheat Train Rigorously This is the more complicated method to get working but gives the most rigorous results. The solution requires installing a series of recycles in streams that flow between the column and the pre-heat train. v 921 Chapter 9: Separation Unit Operations Running the Column When the Column sub-flowsheet configuration is complete, you can run the Column solution algorithm. The Run/Reset buttons can be accessed from any page of the Column property view. The iterative procedure begins when you click Run. When you begin a convergence, a Stop button replaces the Run and Reset buttons. To terminate a convergence procedure, click Stop. Run the Column The Run command begins the iterative calculations necessary to simulate the Column described by the input. A summary showing the iteration number, equilibrium error and the heat and spec errors appear on the Monitor page. Detailed messages showing the convergence status are shown in the Trace Window. The default basis for the calculation is a modified inside-out algorithm. In this type of solution, simple equilibrium and enthalpy models are used in the inner loop, which solve the overall component and heat balances, vapour-liquid equilibrium and any specifications. The outer loop updates the simple thermodynamic models with rigorous calculations. Any estimates that appear in the Column Profiles and Estimates pages are used as initial guesses for the convergence algorithm. If no estimates are present, Petro-SIM begins the convergence procedure by generating initial estimates. Petro-SIM first performs iterations toward convergence of the inner and outer loops (Equilibrium and Heat/Spec Errors) and then checks the individual specification tolerances. The following process occurs when the simulation is running: 1. The status line at the bottom of the screen tracks the calculation of the initial properties used to generate the simple models. 2. The determination of a Jacobian matrix displays, which is used in the solution of the inner loop. If difficulty is encountered when converging the inner loop, the program occasionally recalculates the inner loop Jacobian. If no obvious improvement is being made with the printed equilibrium and heat and spec errors, click Stop to terminate the calculations and examine the available information for clues (refer to Column Troubleshooting) if trouble is encountered achieving the desired solution. 3. The status line reports the inner loop errors and the relative size of the step taken on each of the inner loop iterations. 922 v Column Property View 4. The rigorous thermodynamics is again calculated and the resulting equilibrium, heat, and spec errors reported. 5. The calculation of the inner loop and the outer loop properties continues until convergence is achieved, or you determine that the Column cannot converge and click Stop to terminate the calculation. The Monitor page displays a summary of the convergence procedure for the equilibrium and Heat/Spec Errors. An example of a converged solution is shown in the following figure: When you are working with the Column in the Main build environment, the Column automatically runs when you change: l l A specification value after a converged solution has been reached. The Active specifications, such that the Degrees of Freedom return to zero. Reset the Column The Reset command clears the current Column solution and any estimates appearing on the Estimates page. If you make major changes after getting a converged Column, it is a good idea to Reset to clear the previous solution. This allows the Column solver to start fresh and distance itself from the previous solution. If you make only minor changes to the Column, click Run before resetting. Once the Column calculation has started, it continues until it has either converged, has been terminated due to a mathematically impossible condition, (e.g., being unable to invert the Jacobian matrix), or it has reached the maximum number of iterations. Other than these three situations, calculations continue indefinitely in an attempt to solve the Column unless the Stop button is clicked. Unconverged results can be analyzed, as described in Column Troubleshooting. When you are inside the Column build environment, the column convergence can only be initiated when you click Run on the Column tab. Running the column in the column environment is the same as running it from the Column property view in the Main environment. Column Troubleshooting Although Petro-SIM does not require any initial estimates for convergence, good estimates of top and bottom temperatures and one product accelerate the convergence process. Detailed profiles of vapour and liquid flow rates are not required. v 923 Chapter 9: Separation Unit Operations Should the Column have difficulty, the diagnostic output printed during the iterations provides helpful clues on how the tower is performing. If the equilibrium errors are approaching zero, but the heat and Spec errors are staying relatively constant, the specifications are likely at fault. If both the equilibrium errors and the heat and spec errors do not appear to be getting anywhere, then examine all your input (e.g., initial Estimates, Specifications and tower configuration). When running a Column, keep in mind that the basic Column parameters cannot change. By this, it is meant that Column pressure, number of trays, feed tray locations and extra attachments such as side exchanger and pumparound locations, remain fixed. To achieve the desired specifications, the Column only adjusts variables that have been specified as initial estimates, such as reflux, side exchanger duties, or product flow rates. This includes values that were originally specifications but were replaced, thereby becoming initial estimates. It is your responsibility to ensure you have entered a reasonable set of operating conditions (initial estimates and specifications) that permit solution of the Column. There are obviously many combinations of Column configurations and specifications that make convergence difficult or impossible. Although all these different conditions could not possibly be covered here, some of the more frequent problems include the following. Heat and Spec Errors Fail to Converge This is by far the most frequent situation encountered when a Column is unable to satisfy the allowable tolerance. The following section gives the most common ailments and remedies. Poor Initial Estimates Initial estimates are important only to the extent that they provide the initial starting point for the tower algorithm. To see the initial estimates, click View Initial Estimates on the Monitor page of the Column property view. Generally, poor guesses cause your tower to converge slower. Occasionally the effect is more serious. Consider the following: l l l 924 v Check product estimates using approximate splits. A good estimate for the tower overhead flow rate is to add up all the components in your feed that are expected in the overheads, plus a small amount of your heavy key component. If the tower starts with extremely high errors, check to see that the overhead estimate is smaller than the combined feed rates. Poor reflux estimates usually do not cause a problem except in very narrow boiling point separations. Better estimates are required if you have high Column liquid rates relative to vapour rates, or vice-versa. Towers containing significant amounts of inert gases, for example, H2, N2, etc., require better estimates of overhead rates to avoid initial bubble point problems. A nitrogen rejection Column is a good example. Column Property View Input Errors It is good practice to check all of your input just before running your Column to ensure all your entries, such as the stage temperatures and product flow rates, appear reasonable. Click Input Summary on the Monitor page to display the Column Input in the Trace Window. l l l l Check to ensure your input contains the correct values and units. Typical mistakes are entering a product flow rate in moles/hr when you really meant to enter it in barrels/day, or a heat duty in BTU/hr instead of E+06 BTU/hr. When specifying a distillate liquid rate, make sure you have specified the Distillate rate for the condenser, not the Reflux rate. If you ch

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