®
Aspen FCC 12.1 User
Guide
Version 12.1
August 2003
Copyright (c) 1981-2003 by Aspen Technology, Inc. All rights reserved.
AspenTech®, Aspen Engineering Suite, Aspen FCC®, Aspen Hydrocracker®, Aspen Hydrotreater, Aspen
CatRef®, Aspen Rxfinery, the aspen leaf logo, and Plantelligence® are trademarks or registered trademarks of
Aspen Technology, Inc., Cambridge, MA.
BATCHFRAC and RATEFRAC are trademarks of Koch Engineering Company, Inc.
All other brand and product names are trademarks or registered trademarks of their respective companies.
This manual is intended as a guide to using AspenTech's software. This documentation contains AspenTech
proprietary and confidential information and may not be disclosed, used, or copied without the prior consent of
AspenTech or as set forth in the applicable license agreement. Users are solely responsible for the proper use of the
software and the application of the results obtained.
Although AspenTech has tested the software and reviewed the documentation, the sole warranty for the software
may be found in the applicable license agreement between AspenTech and the user. ASPENTECH MAKES NO
WARRANTY OR REPRESENTATION, EITHER EXPRESSED OR IMPLIED, WITH RESPECT TO THIS
DOCUMENTATION, ITS QUALITY, PERFORMANCE, MERCHANTABILITY, OR FITNESS FOR A
PARTICULAR PURPOSE.
Corporate
Aspen Technology, Inc.
Ten Canal Park
Cambridge, MA 02141-2201
USA
Phone: (1) (617) 949-1000
Fax:
(1) (617) 949-1030
URL: http://www.aspentech.com
Contents
Introduction
1-1
Aspen FCC: Overview .....................................................................................................1-1
Technical Support ............................................................................................................1-1
Using Aspen FCC
2-1
Starting Aspen FCC .........................................................................................................2-1
The Sheets of the User Interface ......................................................................................2-2
General Guidelines for Using the Excel Interface ...........................................................2-2
Saving and Loading Data Files ........................................................................................2-3
Loading Data Files ...............................................................................................2-4
Saving and Loading Parameter or Simulation Worksheets..............................................2-4
The User Interface
3-1
The Command Line Window...........................................................................................3-1
Abort Button.........................................................................................................3-2
No Creep Button...................................................................................................3-2
Close Residuals Button ........................................................................................3-2
Close Button.........................................................................................................3-2
Manual Access to the Command Line .................................................................3-2
Toolbar and Menu ............................................................................................................3-3
Startup Aspen FCC Submenu ..............................................................................3-4
Connect Dialog Box .......................................................................................3-5
Startup Options Dialog Box ...........................................................................3-7
File Submenu........................................................................................................3-8
Setup Cases Submenu ........................................................................................3-10
Worksheets in the Aspen FCC Workbook .....................................................................3-10
Introduction Worksheet......................................................................................3-10
Options Worksheet.............................................................................................3-11
Updating Spec Colors...................................................................................3-12
Option Sheet Options ...................................................................................3-12
Param Worksheet ...............................................................................................3-14
Key Operating Data......................................................................................3-15
Feed Data......................................................................................................3-17
Fresh Feed Preheat Temperature Control.....................................................3-19
Recycle Stream Data ....................................................................................3-19
Fresh Feed Recycle Stream Routings to Riser .............................................3-20
Light Ends Product Streams for Reactor Parameterization..........................3-20
Aspen FCC 12.1 User Guide
iii
Heavy Liquid Product Stream Reactor Parameterization ............................3-22
Heavy Liquid Product Streams for Simplified Fractionation Parameterization
......................................................................................................................3-22
Catalyst Data ................................................................................................3-24
Mechanical Data...........................................................................................3-25
Heat Losses ..................................................................................................3-29
Tuning Data..................................................................................................3-29
Analysis Worksheet............................................................................................3-30
Feed Blends Worksheet......................................................................................3-31
Cat Blend Worksheet .........................................................................................3-33
Simulation Worksheet ........................................................................................3-34
Key Operating Data......................................................................................3-34
Feed Data......................................................................................................3-35
Yields ...........................................................................................................3-36
Catalyst Data ................................................................................................3-37
Product Rates and Properties........................................................................3-38
LP Vectors Worksheet ...................................................................................................3-39
Setting up LP Vectors ..................................................................................3-39
PIMS Vectors Workshet.....................................................................................3-41
PIMS Table Worksheet ......................................................................................3-41
Generating a PIMS Table.............................................................................3-41
Cases Worksheet ................................................................................................3-41
Optimize Worksheet...........................................................................................3-42
Profit Worksheets...............................................................................................3-43
Profit Report Worksheets ...................................................................................3-44
Hidden Worksheets ............................................................................................3-44
Specifying Data
4-1
Specifying Data ................................................................................................................4-1
Setting Up Case Studies ...................................................................................................4-2
Before You Start...................................................................................................4-2
Specifying Varied and Reported Variables..........................................................4-2
Setting up Optimizations..................................................................................................4-4
Independent Variables..........................................................................................4-4
Bounds..................................................................................................................4-5
Setting up Objective Functions ............................................................................4-5
Setting up Optimization Variables and Bounds ...................................................4-8
Setting Up LP Vector Calculations ................................................................................4-11
Running Cases
5-1
Case Types .......................................................................................................................5-1
Running Cases from the FCC Toolbar.................................................................5-1
Running Cases from the FCC Menu ....................................................................5-2
Solver Settings..................................................................................................................5-2
Running a Parameterization Case ....................................................................................5-3
Aspen FCC Options .............................................................................................5-4
iv
Aspen FCC 12.1 User Guide
Entering Data for Parameter Cases ......................................................................5-8
Running the Parameter Case ................................................................................5-9
Running a Simulation Case ............................................................................................5-10
Running Multiple Cases .................................................................................................5-11
Running the Case Study .....................................................................................5-11
LP Vectors Option..............................................................................................5-12
Running an Optimization Case ......................................................................................5-13
Solving the Optimization ...................................................................................5-13
Changing the Behavior of the DMO Solver.......................................................5-14
LP Vector Generation.....................................................................................................5-15
Running LP Vector Generation..........................................................................5-15
Advanced Topics
6-1
Parameter Case Analysis..................................................................................................6-1
Parameter Options on Options Worksheet ...........................................................6-1
Feed Rate Basis ..............................................................................................6-1
Feed Gravity Basis .........................................................................................6-2
Product Gravity Basis.....................................................................................6-2
Light-Ends Product Rate Basis ......................................................................6-2
Heavy Product Rate Basis ..............................................................................6-2
Fractionation Control .....................................................................................6-2
Fresh Feed Basic or Total Nitrogen ...............................................................6-2
Regenerator Control .......................................................................................6-2
Pressure Balance Control ...............................................................................6-3
Param Sheet Input - Key Operating Data.............................................................6-3
Regenerator Temperatures .............................................................................6-3
Carbon on Regen Catalyst..............................................................................6-3
Flue Gas Composition....................................................................................6-4
Air Rate ..........................................................................................................6-4
Pressure Balance ............................................................................................6-4
Heat Removal.................................................................................................6-4
Param Sheet Input - Feed Data.........................................................................................6-4
Feed Type.......................................................................................................6-5
S Crackability.................................................................................................6-5
Refractive Index and Viscosity ......................................................................6-5
Distillation Type.............................................................................................6-5
Feed Metals Option ........................................................................................6-5
Param Sheet Input - Heavy Liquid Product Streams............................................6-7
Param Sheet Input - Catalyst Data .......................................................................6-7
Feed Blend Sheet Review ....................................................................................6-7
Lab Data versus Estimations ..........................................................................6-7
Aromatic Content ...........................................................................................6-7
Cat Blend Sheet Review.......................................................................................6-8
Analysis Sheet Review.........................................................................................6-8
Material Balance ............................................................................................6-8
Heat Balance ..................................................................................................6-8
Aspen FCC 12.1 User Guide
v
Feed Vaporization ..........................................................................................6-9
Reactor Dilute Phase Cracking ......................................................................6-9
Model Tuning...................................................................................................................6-9
Heat Balance Tuning............................................................................................6-9
Over-cracking.....................................................................................................6-12
Catalyst Makeup versus MAT............................................................................6-17
Adding New Catalysts........................................................................................6-18
Work Process......................................................................................................6-19
Unhiding the CST Factors Worksheet ...............................................................6-19
Adding Catalyst Data .........................................................................................6-19
Re-hiding the CST Factors Worksheet...............................................................6-20
Feed Characterization.....................................................................................................6-20
Feed Properties...................................................................................................6-21
Selecting Feeds and Entering Property Information ..........................................6-21
The Aspen FCC Engine..................................................................................................6-23
EO Modeling Background and Examples
7-1
Equation-Oriented Modeling............................................................................................7-1
Pressure Drop Model Example ............................................................................7-1
Model Specifications and Degrees-of-Freedom...................................................7-2
Modes and Multi-Mode Specifications ................................................................7-3
Measurements and Parameters .............................................................................7-4
Changing Specifications with Combo Boxes.......................................................7-4
Optimization.........................................................................................................7-5
DMO Solver Background.................................................................................................7-6
Successive Quadratic Programming (SQP)..........................................................7-6
Changing DMO Parameters .............................................................................................7-7
Basic DMO Parameters........................................................................................7-8
DMO Command Window Output and Log Files .............................................................7-8
DMO Solver Log Files.......................................................................................7-10
ATSLV File Problem Information .....................................................................7-10
Basic Iteration Information ..........................................................................7-10
Largest Unscaled Residuals .........................................................................7-11
Constrained Variable....................................................................................7-11
General Iteration Information.......................................................................7-12
Nonlinearity Ratio ........................................................................................7-12
Troubleshooting
8-1
Aspen FCC Stops Responding .........................................................................................8-1
Resetting Connection to the Aspen Plus Server...............................................................8-1
Error Recovery for Parameterization ...............................................................................8-2
Error Recovery for Simulation.........................................................................................8-3
Solver Performance ..........................................................................................................8-4
Dealing with Infeasible Solutions ........................................................................8-4
Scaling..................................................................................................................8-6
Dealing with Singularities....................................................................................8-6
vi
Aspen FCC 12.1 User Guide
Notes on Variable Bounding ................................................................................8-8
Run Time Intervention .........................................................................................8-8
The Model Is Not Solving................................................................................................8-8
Licensing Errors ...............................................................................................................8-9
The FCCU Model
9-1
The FCCU Model.............................................................................................................9-1
Twenty-One-Lump Kinetics ............................................................................................9-1
Sulfur Distribution............................................................................................................9-6
Coke Production and Handling ........................................................................................9-8
Kinetic Coke.........................................................................................................9-8
Metals Coke..........................................................................................................9-9
Feed Source Coke.................................................................................................9-9
Stripper Source Coke (Occluded Coke) ...............................................................9-9
Stripper Source Coke (Occluded Coke) .........................................................9-9
Initial Vapor Entrainment...............................................................................9-9
Stripper Performance Curve Slope...............................................................9-10
Material Balance Reconciliation ....................................................................................9-10
FCCU Model Configuration...........................................................................................9-11
Risers..................................................................................................................9-11
Reactor ...............................................................................................................9-13
Regenerator ........................................................................................................9-15
Stripping Zone Model ........................................................................................9-16
Catalyst Standpipe, Slide Valve and Transfer Line ...........................................9-16
FCC Nozzle System ...........................................................................................9-16
Simple Fractionation ......................................................................................................9-16
Aspen FCC Input Data Requirements............................................................................9-18
Feed Blending ....................................................................................................9-18
Index
Aspen FCC 12.1 User Guide
9-1
vii
viii
Aspen FCC 12.1 User Guide
CHAPTER 1
Introduction
Aspen FCC: Overview
Aspen FCC is AspenTech's state-of-the-art Fluidized Catalytic
Cracking Unit simulation system that can be used for modeling and
optimizing a FCCunit in petroleum refineries. Aspen FCCalso
provides full Windows interoperability to facilitate process and
design engineers’ work processes. Aspen FCCis part of the Aspen
Engineering Suite™of process design, simulation, and
optimization tools.
Technical Support
AspenTech customers with a valid license and software
maintenance agreement can register to access the Online
Technical Support Center at:
http://support.aspentech.com/
This web support site allows you to:
• Access current product documentation
• Search for tech tips, solutions and frequently asked questions
• (FAQs)
• Search for and download application examples
• Submit and track technical issues
• Send suggestions
• Review lists of known limitations
Registered users can also subscribe to our Technical Support eBulletins. These e-Bulletins are used to proactively alert users to
important technical support information such as:
• Technical advisories
Aspen FCC 12.1 User Guide
Introduction • 1-1
•
•
Product updates
Service Pack announcements
Customer support is also available by phone for customers with a
current support contract for this product. The hours listed are in
local time.
Hours:
Phone:
Fax:
E-Mail
08:00 . 20:00
1-888-996-7100 (toll-free from US, Canada, Mexico)
1-281-584-4357 (US, Canada)
1-617-949-1724 (Cambridge, MA)
1-281-584-1807 (Houston, TX)
support@aspentech.com
Online Technical Support Center
Phone and E-mail
North America And the Caribbean
Argentina Office
Hours:
Phone:
Fax:
E-Mail
09:00 . 17:00
0800-333-0125 (toll free to US)
54-11-4361-7220
54-11-4361-7220
info@tecnosolution.com.ar
Brazil Office
Hours:
Phone:
Fax:
E-Mail
09:00 . 17:00
000-814-550-4084 (toll free to US)
55-11-5012-0321
55-11-5012-4442
tecnosp@aspentech.com
Europe, Gulf Region, and Africa
Hours:
Phone:
Country
specific tollfree
numbers:
Belgium
Denmark
Finland
France
Ireland
1-2 • Introduction
08:30 . 18:00 (Central European Time)
32-2-701-95-55
(0800) 40-687
8088-3652
(0) (800) 1-19127
(0805) 11-0054
(1) (800) 930-024
Aspen FCC 12.1 User Guide
Netherlands
Norway
Spain
Sweden
Switzerland
UK
(0800) 023-2511
(800) 13817
(900) 951846
(0200) 895-284
(0800) 111-470
(0800) 376-7903
Fax:
E-Mail
32-2-701-94-45
atesupport@aspentech.com
Asia and Pacific Region
Tokyo Office
Hours:
Phone:
Fax:
E-Mail
09:00 . 17:30
81-3-3262-1743
81-3-3262-1744
atjsupport@aspentech.com
Singapore Office
Hours:
Phone:
Fax:
E-Mail
Aspen FCC 12.1 User Guide
09:00 . 17:30
65-395-39-00
65-395-39-50
atasupport@aspentech.com
Introduction • 1-3
1-4 • Introduction
Aspen FCC 12.1 User Guide
CHAPTER 2
Using Aspen FCC
The following section explains the basics of using Aspen FCC.
Starting Aspen FCC
1
From the Windows Start menu, click Programs | AspenTech |
Aspen Engineering Suite | Aspen Rxfinery 12.1 | Aspen
FCC 12.1 | Aspen FCC 12.1.
This launches Excel and opens the Aspen FCC GUI.
2 When prompted by Excel, click the Enable Macros button.
When the Aspen FCC workbook is loaded, there is no active
connection to the Aspen FCC model, which is an Aspen Plus
flowsheet. The workbook consists of several spreadsheets where
various data can be entered and retrieved. The application also
Aspen FCC 12.1 User Guide
Using Aspen FCC • 2-1
creates a new menu on the Excel menu bar called AspenFCC. This
menu provides access to all of the GUI’s primary functions
including connecting to the model. Through the Startup Aspen
FCC submenu, you can:
• Load the flowsheet
• Modify startup options
• Reset the Aspen Plus connection
Most of the other menu commands will be inactive until the
flowsheet is loaded. For more information, refer to Startup Aspen
FCC Submenu. on page 3-3.
The Sheets of the User Interface
When Aspen FCC is started for the first time, the default
spreadsheet is the Introduction sheet. You can navigate to other
data entry or results areas by selecting the appropriate tab at the
bottom of the Excel window.
You can open a number of the sheets, including the LP Vectors,
Cases, Optimize and the Profit sheets, by selecting the
corresponding item from the AspenFCC | Setup Cases menu as
shown below.
For more information about these sheets, General Guidelines for
Using the Excel Interface
Most of the features of Excel are available in the Aspen FCC
workbook. However, you should only use these features with an
understanding about the overall functioning of the workbook. This
section provides an overall description of the workbook and
functioning. Other sections provide more detail about the
worksheets that you will normally use for running the Aspen FCC
model.
Here are some things to consider as you use the workbook:
2-2 • Using Aspen FCC
Aspen FCC 12.1 User Guide
•
•
•
The only fields that you can make an entry in that the model
will use are those colored blue.
Entries into number fields that are not colored blue will be
overwritten by the workbook after a case is executed.
If you use a formula in a field that is colored blue, it will be
overwritten after a case is executed; therefore, enter only
values in these fields.
If you change an option with a combo box, the color-coded fields
are not automatically updated; you must click the
button on
the Aspen FCC toolbar that will appear after you connect.
• If a case does not converge, the calculation engine will contain
a starting point that is not good for subsequent cases.
• Use the file save commands to frequently save calculations.
These will be needed to restore a case if the problem does not
converge.
• The data you enter into the Parameter and Simulation
worksheets is automatically saved by the workbook when a
case is run and can be retrieved after you restore a case to
create a good starting point for the calculation engine.
• The model is an equation-based model and needs a good
starting point to converge. Therefore, be careful about large
changes in the independent variables (color coded blue).
These guidelines will be become more meaningful as you read the
material in this section and in the sections about specific cases.
You can save the data file and load the file from the buttons
provided on the FCC toolbar. You can also save and load the file
using the commands on the AspenFCC | File menu. You can make
any run by selecting the run type from the dropdown box or from
the commands on the AspenFCC | Run Cases menu.
Saving and Loading Data Files
It is frequently desirable to save the data in the FCC model,
because the default when the model is started is to load the base
problem data. Once the model has been tuned to your data, you can
save data to use as the new starting point.
To Save FCC Model Data:
1 On the Aspen FCC toolbar, click the Save User Data button.
-orSelect the AspenFCC | File | Save Case Data menu command.
Aspen FCC 12.1 User Guide
Using Aspen FCC • 2-3
The Save User Data to File dialog box appears
2
3
Enter the path and filename; then click Save to return to the
Save User Data to File dialog box.
Click Save to save the model data.
Note: You can save all of the data currently in the model or just
the input data from the spreadsheet. Typically, you use the default
option to save all of the model data. The data is saved to an ASCII
file, which can be greatly compressed to save disk space.
Loading Data Files
To load data saved to an ASCII file using the Save Case Data
command:
1 On the Aspen FCC toolbar, click the Load User Data button.
-orSelect the AspenFCC | File | Load Case Data menu
command.
The Load User Data from File dialog box appears.
2 Browse to the file of interest.
-orType in the file name and path directly in the filename and
path text boxes.
3 Click Load to load the values from the data file into the FCC
flowsheet.
Saving and Loading Parameter or
Simulation Worksheets
You can save and load just the parameter and simulation
worksheets at any time and retrieve them later.
This option is useful if you think that your future Parameter or
Simulation run is a big change and, therefore, the problem might
fail. In this case, you can save your input sheet and load it again to
start back from a good solution.
2-4 • Using Aspen FCC
Aspen FCC 12.1 User Guide
To Save Your Input Worksheets:
• From the menu, click Aspen FCC | File | Save User Input
Sheet.
To Load Your Input Worksheets:
• From the menu, click Aspen FCC | File | Load User Input
Sheet.
Both parameter and simulation worksheet are updated when the
command is executed.
Aspen FCC 12.1 User Guide
Using Aspen FCC • 2-5
2-6 • Using Aspen FCC
Aspen FCC 12.1 User Guide
CHAPTER 3
The User Interface
The Aspen FCC User Interface consists of three major
components:
• The Command Line Window.
• The Menu and Toolbar.
• THe Worksheets.
The Command Line Window
The Aspen Plus Command Line window displays the output of
commands sent to the Aspen FCC model. It appears automatically
when loading Aspen FCC and when running cases. After
connecting to the FCC flowsheet, you can also manually open this
window by selecting the AspenFCC | Tools | Display Command
Line menu command.
When Aspen FCC is loading, the Command Line window appears
briefly, letting you observe the commands that are being sent to the
Aspen FCC 12.1 User Guide
The User Interface • 3-1
model during the flowsheet instantiation. You will not be able to
access any functions on the command line at this time.
When a case is running, the Command Line window opens
automatically and lets you observe the commands that are being
sent to the model and the convergence path of a solution. When the
command line opens automatically in these instances, you can use
only the Abort, No Creep, or Close Residuals buttons.
Abort Button
Click the Abort button to abort the solving of a case.
If you click the Abort button while a case is running, you must
wait until the following messages appear in the command line
window:
Error return due to an ABORT message from the user
communications file DMO.MSG
Problem failed to converge
You can now click the Close button to close the command line
window and return to the model. You should then load a data file
to ensure the next case starts from a good converged solution.
No Creep Button
When running a case, the default is to creep the solver (take small
steps) for a few iterations to provide robust behavior. Once you
have gained experience with the model and are confident that a
particular case will solve well without the default number of creep
steps, you can manually turn the creep steps off by clicking the No
Creep button.
You can click the No Creep button while a problem is converging.
This causes the solver to eliminate the creep in the next iteration.
Close Residuals Button
Use the Close Residuals button to have the model close the
residuals without minimizing the objective function convergence.
You might find this useful in cases where the objective function
very nearly reaches a maximum value, but the convergence of the
objective does not close.
Close Button
This button closes the Command Line window and returns you to
the user interface.
Click the Close button only:
• After a run has failed to converge .
• If you aborted a case and the command line message run
aborted by the user appears.
• If you opened the Command Line window manually, and you
have finished using it..
Manual Access to the
Command Line
3-2 • The User Interface
After connecting to the FCC flowsheet, select the AspenFCC |
Tools | Display Command Line menu command. The Aspen Plus
command line window appears. When you open the command line
Aspen FCC 12.1 User Guide
in this fashion, you have immediate access to the Close button.
You can also enter valid commands on the command line.
The Abort, Finish, and Close Residuals buttons have no effect
when the command line has been opened manually unless the solve
command is invoked to run Aspen Plus. The Close button will
close the command line window and return to the Excel
spreadsheet. While the command line window is open, you will not
be able to access the Excel spreadsheet.
The command line window can be a very powerful tool in troubleshooting problems since the commands sent to the model and the
solutions of the model will be stored in the buffer. You can scroll
through the buffer (the top window of the command line) to see
convergence paths and any error messages generated when trying
to solve a problem.
Toolbar and Menu
When the Aspen FCC workbook is selected, Microsoft Excel is
loaded and FCC adds a new menu to the Excel menu bar labeled
AspenFCC. This menu contains commands that activate VBA
macros within FCC. There is also an Aspen FCC toolbar which
only appears once the workbook is connected to the Aspen FCC
flowsheet.
This section explains the features that are available from the Aspen
FCC menu and toolbar. Many of the commands are associated with
the cases for FCC modeling. Details about these commands are
located in the chapters of this manual describing the cases.
When you select AspenFCC on the Excel menu bar, the menu
appears as shown in the figure below. Note that most of the
commands are on submenus.
Aspen FCC 12.1 User Guide
The User Interface • 3-3
AspenFCC Drop-Down Menu Before Connection
Some of the options are dimmed in this figure because the
workbook has not yet been connected to the calculation engine
through the server. The options under Development Tools are for
advanced functions in the workbook and will not be covered in this
chapter.
Startup Aspen FCC
Submenu
The Startup Aspen FCC submenu contains the commands you
will typically use when you first activate the Aspen FCC
workbook.
When you select Startup Aspen FCC, the menu shown above
appears. The three commands on this submenu are described
below.
3-4 • The User Interface
Aspen FCC 12.1 User Guide
Startup Aspen FCC Commands
Connect Dialog Box
Aspen FCC 12.1 User Guide
Command
Function
Load FCC
Flowsheet
Startup Options
Reset ApMain
Connect the workbook and load a problem file
Load a problem file automatically or manually
Resets the connection with the Aspen Plus server
The Load FCC Flowsheet option is normally the first command
you will use. This command displays the Connect dialog box. The
Reset ApMain command causes the workbook to break the
connection with the server. This is necessary if you want to use the
Excel File menu. If you do not close the workbook at this point,
you can use the Load FCC Flowsheet command to reconnect the
workbook.
1 On the Excel menu bar, select AspenFCC | Startup Aspen
FCC | Load FCC Flowsheet.
The User Interface • 3-5
The Connect dialog box appears.
Connect Dialog Box
2
In the Host box, enter the name of the host computer (normally
your computer) using all lower case letters.
If the correct computer name is entered, the Browse button in
the Problem area will become enabled.
Note: You can easily determine the computer name if it is not
known:
•
•
3-6 • The User Interface
Win2000: Right-click the My Computer icon on the
computer desktop and select Properties from the pop-up
menu. Click the Network Identification tab where the full
computer name will be listed near the top.
Windows XP: Right-click the My Computer icon on the
computer desktop and select Properties from the pop-up
menu. Click the Computer Name tab. The computer name
will be listed in the Full Computer Name field.
Aspen FCC 12.1 User Guide
3
Click the Browse button in the Problem area, navigate into the
Apinit directory, select the file fcc.appdf, and then click
Open.
The Connect dialog box reappears, and the fcc.appdf file
name and directory should now appear in the Problem area.
4 Click the Browse button in the User Data File area, select the
file FCC12_1_demo.var, and click Open.
The Connect dialog box reappears, and the file name and
directory of FCC12_1_demo.var should appear in the User
Data File area.
5 At the bottom of the Connect dialog box, click OK.
On a 750 MHz Pentium III PC, such as a Dell Inspiron 8000, it
requires approximately two minutes to initialize the FCC
flowsheet and load the data into the Excel GUI. During this
time, the Excel cursor will appear as an hourglass symbol and
the Excel status line will display the message Loading Aspen
FCC flowsheet. The cursor will return to the normal cross
shape and the status line will display Ready when the process is
complete.
Once the connected to the flowsheet is established, the
previously inactive AspenFCC menu commands become
active, and the Aspen FCC toolbar is created.
6 Now save the workbook using the Excel File | Save command,
to preserve the computer name and FCC appdf file location
entered in the Connect dialog box.
You are now ready to begin using Aspen FCC.
Startup Options Dialog
Box
Aspen FCC 12.1 User Guide
The Startup Options dialog box is illustrated below. This dialog
box lets you specify a default problem solution to load into the
workbook other than FCC.APPDF (the base solution).
The User Interface • 3-7
Startup Options Dialog Box
When the Aspen FCC workbook is opened, there is by default no
connection established with the FCC flowsheet. Furthermore, once
the connection is established, the data loaded into the spreadsheet
will be the data that comes with the generic model. You can
change these default settings to improve efficiency. By modifying
the startup options, you can automatically connect to the FCC
spreadsheet and load a specific user data file immediately upon
opening the FCC GUI.
At the top of the Startup Options dialog box, you can choose to
make a connection to the FCC model either manually or
automatically. If you select Automatic Startup, the spreadsheet
will automatically establish a connection to the model whenever it
is opened.
The Startup Options dialog box also has an option to load in a set
of data other than the default problem data. Automatically loading
data that matches your plant is more convenient. For more
information on saving and loading data, see Saving and Loading
Data Files on page 2-3.
To Set Startup Options:
1 On the Excel menu bar, select AspenFCC | Startup Aspen
FCC | Startup Options.
The Startup Options dialog box appears.
2 Select Manual Startup or Automatic Startup. Your choice
will determine whether the connection to the FCC model is
made manually or automatically.
3 If you chose the Automatic Startup option in Step 2, you can
load a set of data other than the default problem data in the
fcc.appdf file. To do so, select the Load User Data from
File? checkbox.
4 In the File Name box, enter the name of the data file to be
loaded (including the full path). Normally, this is a file that you
have saved from a previous execution of the program.
5 Click OK.
File Submenu
The second submenu on the AspenFCC menu is File. There are
four commands in this menu, which are summarized below.
The first two commands display dialog boxes that you can use to
retrieve or save a case file. You can use the last two commands to
retrieve or save information you have entered in the Param or
Simulation worksheets.
3-8 • The User Interface
Aspen FCC 12.1 User Guide
Command
Function
Load Case Data
Save Case Data
Load User Input
Sheet
Save User Input
Sheet
Brings up a dialog box to load a case file
Brings up a dialog box to save a case file
Loads data you previously entered on a Parameter
or Simulation worksheet
Saves data you previously entered on a Parameter
or Simulation worksheet
It is very important for you to be familiar with the Load Case
Data and Save Case Data commands. The FCC model is an
equation-based model and can be moved from a base solution to
another base solution, if the move is not too large. Normally, as a
very general rule, too large means a move of about 20% to 30% on
values other than temperatures. Temperatures changes can be in
the range of 10 to 20 °F.
With experience, you will become more familiar with the
magnitude of changes that the model can accommodate. However,
when a solution is not achieved, the solver is left with a bad
starting point. You will need to load in a good starting point and
this is done with the Load Case Data command. Therefore, it is
good practice to save cases with the Save Case Data command for
later retrieval.
The Load User Input Sheet and the Save User Input Sheet
options are workbook operations you can use to avoid retyping
data if it is lost in a run that doesn’t converge. After you retrieve a
case, the values in worksheets will be updated. If you have entered
data on the Parameter or Simulation worksheet, this data will be
overridden. To retrieve this data, execute the Load User Input
Sheet command. If you need to save the data you have entered,
execute the Save User Input Sheet command. These can also be
activated by buttons on the toolbar:
Aspen FCC 12.1 User Guide
The User Interface • 3-9
Save User Data button
Load User Data button
Setup Cases
Submenu
The third submenu on the AspenFCC drop-down menu is Setup
Cases. This submenu will be dimmed until you successfully
connect to the workbook to the calculation engine as explained
above.
The Setup Cases submenu contains seven commands, which are
summarized below.
Command
Function
Case Study
Optimization
LP Vectors
PIMS Vectors
Profit 1
Profit 2
Profit 3
Set up case studies
Set up optimization calculations
Set up LP vectors
Set up PIMS vectors
Set up profit function number 1 for optimization case
Set up profit function number 2 for optimization case
Set up profit function number 3 for optimization case
For more information about setting up cases, see Specifying Data.
Worksheets in the Aspen FCC
Workbook
Introduction
Worksheet
3-10 • The User Interface
Besides displaying the logo for the workbook, the Introduction
worksheet provides version data for product, flow sheet, Excel
interface, and catalyst library. This data is located below the
opening display and is displayed by moving the scroll bar, or
paging down. A place for notes and/or comments is located below
the version information.
Aspen FCC 12.1 User Guide
Options Worksheet
You set the main AspenFCC model configurations and data entry
options on the Options sheet. Under most conditions, you should
only have to make modifications to this sheet once, when the
model is first being customized to your specific FCC unit. The
sheet is self-documented, with the general instructions listed at the
top of the sheet, and a detailed description given next to each
combo box option.
A summary of the general instructions and rules of combo boxes
are given below:
• The options selected in the combo boxes are applied for all
cases.
• Combo boxes only operate once the spreadsheet is connected
to the FCC model. (For information on how to connect to the
flowsheet, see Connect Dialog Box.on page 3-4.)
• Selecting a different option in a combo box changes the spec of
specific variables. Recall that a variable’s spec determines if it
is calculated, kept fixed, or varied as a degree of freedom
depending upon the solver’s run mode.
• Changing the option in a combo box does not automatically
refresh the Param or the Simulation sheets to reflect which
variables are calculated and which variables are fixed. Recall
that the fixed variables have a blue background, while those
that are calculated have a white background. There are three
Aspen FCC 12.1 User Guide
The User Interface • 3-11
methods to update the Param and Simulation sheets,
described in the following section.
Updating Spec Colors
Method 1:
1
On the AspenFCC toolbar
,
click the Update Spec Color button
.
This refreshes both the Param and the Simulation sheets.
Note: If you click the Update Spec Color button too early, before
the new option is processed, the following error appears:
If this appears, click OK to continue, and wait until the combo box
option has finished running the macro before trying to update the
colors.
Method 2:
1 On the main toolbar menu, select AspenFCC | Development
Tools | Update Param Sheet color for the Param sheet.
2 On the main toolbar menu, select AspenFCC | Development
Tools | Update Simulation Sheet color for the Simulation
sheet.
Method 3:
1 Run a Param case. For information on how to run a Param
case, see Running a Parameterization Case. on page 5-3
This automatically refreshes the Param sheet when the data is
passed back to the spreadsheet from the solver.
2 Run a Simulation case to update the color on the Simulation
sheet.
Of the three methods, the first is the simplest and is recommended.
Option Sheet Options
The options available on the Option sheet are summarized below:
#
Combo Box
Name
1
Feed Rate Basis Input volume rates
Input mass rates
Fresh Feed
Input API
2
3-12 • The User Interface
Options available
Description
Default
Enter fresh feed and recycle
Default
rates on volume or mass basis. #1
Enter API or Specific Gravity
Default
Aspen FCC 12.1 User Guide
Gravity Basis
3
4
5
6
7
8
9
Input SG
K Const for LP
Ca Const for LP
H Const for LP
Product Gravity Input API
Basis
Input SG
Light-Ends
Product Rate
Basis
Heavy Product
Rate Basis
Input volume rates
Input mass rates
for all feeds on Param and
Simulation sheets. K factor,
Aromatic content CA and H
content are for running LP
vectors.
Enter API or Specific Gravity
for light naphtha (debutanizer
bottoms) and heavier products.
Enter light-end product rates on
volume or mass basis.
#1
Default
#1
Default
#1
Enter heavy ends product rates Default
(light naphtha and heavier) on #1
volume or mass basis.
Note: Should be consistent with
Fractionation Control.
Set product (heavy naphtha and Default
Fractionation Input vol, HN and HCO rate
heavier) flow control or
#1
Control
const.
distillation
point
control.
Input mass, HN and HCO rate
const.
Input vol, all use TBP90
Input mass, all use TBP90
Input vol, HN/LCO/HCO rates
const
Input mass, HN/LCO/HCO
rates const
Custom 1
Custom 2
Custom 3
Fresh Feed
Input Concarb
Enter fresh feed Conradson
Default
Concarb or
carbon (CRC) or Ramsbottom #1
Input Ramsbottom
Ramsbottom
carbon content.
Fresh Feed
Input Basic N
Enter fresh feed basic nitrogen Default
Basic or Total Input Total N
or total nitrogen content. The #1
Nitrogen
default basic to total nitrogen
ratio is 1:3. This ratio is
changed in cells.
Select either complete or partial Default
Regenerator
Complete Combustion
Control
Flue Gas O2 const float air vol combustion options. Select the #1, 1.1
appropriate option from the
Flue Gas O2 const float air
submenu of options in the
mass
second combo box.
Flue Gas O2 const float O2 inj
vol
Flue Gas O2 const float O2 inj
mass
Air and O2 inj const float Flue
Aspen FCC 12.1 User Guide
Input volume rates
Input mass rates
The User Interface • 3-13
Gas O2
Bed T & FG O2 const float Cat
Cooler & air vol
Bed T & FG O2 const float Cat
Cooler & air mass
Partial Combustion
Bed T const float air vol
Bed T const float air mass
Bed T const float O2 inj vol
CO2/CO const float air vol
CO2/CO const float air mass
CO2/CO const float O2 inj vol
CO const float air vol
CO const float air mass
CO const float O2 inj vol
CRC const float air vol
CRC const float air mass
CRC const float O2 inj vol
10 Pressure
All pressures const
balance control WG to RX DP const
WG-RX and RX-RGN DP
const
11 Light Naphtha Input C4 content
Front-End
Input RVP
Control
12 Catalyst
Activity
Control
Param Worksheet
3-14 • The User Interface
Input ECAT MAT
Input make-up rate
Enter pressures or pressure
drops as constants.
Default
#3
Enter C4 content or RVP. Note
that both inputs are required for
parameterization, so both
remain blue on Param sheet
regardless of selection.
However, only the selected
option is fixed (blue color) on
the Simulation sheet.
Enter MAT or make-up rate as
constant. Note that both inputs
are required for
parameterization, so both
remain on blue on Param sheet
regardless of selection.
Default
#1
Default
#1
Once the main options are selected on the Options sheet, enter the
process and laboratory data on the Param sheet. General
information about using this sheet is shown at the top of the sheet
and is reported below:
• Use this sheet to enter data for a Parameter case run.
Aspen FCC 12.1 User Guide
•
•
•
•
•
Colored cells are input data. Run the AspenFCC |
Development Tools | Update Param Sheet Color macro to
confirm color is correct with current options.
In Equation Oriented terms, the colored cells have Const or
Meas specs.
This data may not be consistent with the last model runs as a
Simulate case, Case Study, etc. This is the last Param case, not
the last model run.
Before running this case, check the Options sheet. If options
are changed, update the spec colors.
Do not change the position of any cell on this screen. The
Excel VBA code expects the cells to be at their current
positions.
Additional instructions on using this sheet are as follows:
• Enter data in the units of measurement shown. Units of
measurement cannot be changed from the Param sheet. To
change the units of measurement for individual variables or a
group of variables, contact AspenTech.
• Fill out as many data entries as possible before running a
Param case. Sending a consistent set of operating conditions
improves the chances of successful convergence.
The data to be entered on this sheet is broken up into twelve subsections as follows:
Section
Title
1.
2.
3.
4.
5.
6.
7.
8.
Key operating data
Feed data
Fresh feed preheat temperature control
Recycle stream data
Fresh feed and recycle stream routings
Light ends product streams for reactor parameterization
Heavy liquid product streams for reactor parameterization
Heavy liquid product streams for simple fractionator
parameterization
Catalyst data
Mechanical data
Heat losses
Tuning data
9.
10.
11.
12.
Key Operating Data
Aspen FCC 12.1 User Guide
The KEY OPERATING DATA section contains such things as
key temperatures, pressures, air rates, and steam rates related to the
regenerator, reactor, and stripper. Items with a blue background are
The User Interface • 3-15
required inputs. These CONST and MEAS variables are used to
parameterize the model to actual operating conditions.
Specific information to be aware of when entering data is as
follows:
• Riser Outlet Temperature: Enter the vapor temperature
where the catalytic cracking and thermal cracking have
terminated (outlet of the dilute phase – see the riser drawing in
the mechanical data section).
• Air rate for MAB: If the flow meter is on a dry basis, enter a
very low value (0.01%) for the air relative humidity entry.
• Air blower discharge pressure and temperature: These
entries are used for enthalpy calculations only. They are not
connected to the pressure balance of the regenerator-reactorwgc circuit. The AspenFCC model does not model the MAB or
the Wet Gas Compressor. Constraints from these pieces of
equipment can only be taken into account by limiting the air
flow rate and the wet gas compressor suction rate during an
optimization run.
• Sign of Rg/Rx DP: Set to –1 if the regen pressure is greater
than the reactor pressure (default). Set to +1 if the opposite is
true.
• Lift Steam, Dispersion (or Atomizing Steam), Reactor
Stripping Steam: The units of measurement shown for the
rate, temperature and pressure columns correspond to the
dispersion steam to the bottom of VRISER1 (see mechanical
data section). Enter all of the steam data in the units of
measurement shown.
• Lift Gas: Some FCC units have a recycle stream from the
secondary absorber offgas to the bottom of the riser as a
method to minimize lift steam which is detrimental to the
catalyst. In the AspenFCC model, the Lift Gas stream
composition is approximated to be inert (Nitrogen). This
simplification ignores the reaction mechanisms of an actual
offgas stream, but it does model the enthalpy effect on the fresh
catalyst entering the riser.
3-16 • The User Interface
Aspen FCC 12.1 User Guide
Param Sheet - Key Operating Data
Feed Data
The FEED DATA section contains inputs for up to ten fresh feed
streams. Depending upon the feed rate basis option selected on the
Options sheet, either the volume or the mass is entered in the cells
highlighted in blue.
There is a feed type option for each feed through an associated
combo box. Select the most appropriate feed type from the drop
down menu of types available. The following table provides a brief
description of the standard feed types available.
Aspen FCC 12.1 User Guide
#
Feed Type
Description
1.
VGO
2.
3.
4.
5.
6.
7.
8.
9.
10.
HTVGO
LCKGO
HCKGO
MXCKGO
RESID
HOIL
FCCGO
NAPHTHA
SYN
Atmospheric Tower Gas Oil, Vacuum Tower Gas
Oils (LVGO and HVGO)
Hydro-treated Gas Oils
Light Coker Gas Oil
Heavy Coker Gas Oil
Mixed Coker Gas Oil
Resid (Atmospheric Tower bottoms)
HOIL
FCC LCO/HCO type material
Naphtha feed (430 °F and lighter)
Synthetic crude
The User Interface • 3-17
11. NOT FOUND
Same as VGO (Default)
These feed types are found on the hidden sheet Feed Input.
To unhide this sheet:
• From the Excel menu bar, click Format | Sheet | Unhide |
Feed Input.
Contact AspenTech to add a new feed type to this list.
Once the feed type is selected, enter all the analytical data for that
feed, including the API (or specific gravity), sulfur content,
nitrogen content (total or basic), Conradson or Ramsbottom
carbon, refractory index, viscosity, and distillation. A combo box
option is available for either specifying the refractory index
measurement, or to have the refractory index estimated by
selecting the Estimate option. The viscosity measurement can be
entered in either cST or SUS, or you can have the model also
estimate this value by choosing the appropriate option in the
viscosity combo box for each feed. In addition to entering the 9point distillation for each feed, you must specify the distillation
type (D86, D1160, D2887, or TBP) by selecting the appropriate
item from the distillation combo box.
The final entry is to specify the feed metal contents of the feed
streams. A feed metals combo box is included to select how the
feed metals are reconciled with the ECAT metals. The default is to
enter feed metals.
3-18 • The User Interface
Aspen FCC 12.1 User Guide
Param Sheet – Feed Data
Fresh Feed Preheat
Temperature Control
The default setting for the preheat temperature of the fresh feeds is
that all of the fresh feeds are combined upstream to the riser and
they are all mixed at the same temperature. This temperature is
entered in the Combined feed temperature 1 cell. Although the
Combined feed temperature 2 is also highlighted in blue, it is not
necessary to enter a value since it is not used by the model under
the default settings. Contact AspenTech if changes need to be
made to the default configuration.
Param Sheet – Fresh Feed Preheat Temperature Control
Recycle Stream Data
Aspen FCC 12.1 User Guide
There are four recycle streams available:
• Heavy naphtha
• LCO
• HCO
• Bottoms
The User Interface • 3-19
The flow rate (volume or mass), and the preheat temperature of
each stream are entered in this section. Do not set any of the
recycle streams to zero.
Param Sheet – Recycle Stream Data
Fresh Feed Recycle
Stream Routings to Riser
Each individual fresh feed stream and recycle stream can be sent to
the bottom feed nozzle or the upper feed nozzle, or a combination
of the two. Setting the feed routing is done in this section. For
additional information on the model layout of the bottom and
upper feed nozzles, refer to the Mechanical Data section. on page
3-25.
To specify that a stream enters the riser at the bottom feed
nozzles:
• Set the ratio to 1.0.
To specify that a stream enters the riser at the upper feed
nozzles:
• Set the ratio to 0.0.
Note: A minimum amount of material must be specified for both
injection points. Therefore, even if in actuality all feed goes to the
bottom of the riser, at least one of the non-zero feed streams must
be set to a ratio factor less than 1.0, such as 0.9999.
Param Sheet – Feed Stream Routings to Riser
Light Ends Product
Streams for Reactor
Parameterization
3-20 • The User Interface
The flow rate and gas chromatograph (GC) composition of up to
three vapor flow rates, up to five liquid flowrates, and the light and
heavy naphtha streams are entered in this section. The first three
columns are strictly for vapor flowrates.
Aspen FCC 12.1 User Guide
Note: The unit of MMCUFT/DAY for the vapor streams is
interpreted as millions of standard cubic feet per day. The GC
composition for the vapor streams can be entered on a %mole or
%volume basis (no difference), while that of the liquid streams is
strictly on a %volume basis.
General rules for entering data in this table are:
• External streams with C6 or lighter components are entered in
this table, with a negative value for the flow.
• At least one of the components of any given stream must be
nonzero. Even if there is no flow associated with the stream,
setting the GC’s to zero can lead to model robustness issues.
• None of the individual components can have zeros across all
streams. If the GC for all streams are such that one (or more) of
the components listed in the table is zero, you should still
assign a small amount to the component(s) in question under
the most logical stream. Leaving a component at zero
composition can result in negative yields and model robustness
issues.
• Setting the heavy naphtha flow to exactly zero is permitted, but
ensure that at least one of its components is nonzero.
• Enter the light naphtha (or debutanizer bottoms) flow rate in
this table and the next two tables.
Aspen FCC 12.1 User Guide
The User Interface • 3-21
Param Sheet – Light Ends Product Streams for Reactor
Parameterization
Heavy Liquid Product
Stream Reactor
Parameterization
The heavy liquid product streams include the light naphtha
(debutanizer bottoms), heavy naphtha, LCO, HCO and Bottoms
streams. The flow rate, API, and 9 point distillation data for these
five streams must be entered in this table and in the following table
(for simplified main fractionator simplification).
Param Sheet – Heavy Liquid Product Streams for Reactor
Parameterization
The data entered in this table sets the standard yields for the reactor
kinetics, while the same data entered in the next table is strictly to
set how the product streams are actually separated. If a cut has zero
flowrate or does not exist, do not enter zero as the flowrate.
Instead, enter a small non-zero number (1 to 10 BPD) to avoid
numerical problems with the solver.
Heavy Liquid Product
Streams for Simplified
Fractionation
Parameterization
The same flowrate, API, and distillation information entered in the
previous table must be entered in this one as well. Again, do not
enter zero for any of the cuts, even if the cut has zero flowrate or if
the cut does not exist on your unit. Enter a small non-negative
number such as 1 to 10 BPD.
Other properties highlighted in blue need to be entered. The sulfur
weight percent of all five heavy liquid cuts needs to be specified,
regardless if the cut is non-existent or actually has a zero flowrate
measurement. The sulfur weight percent must be entered in
increasing order going from the lightest cut to the heaviest cut.
Consult the sulfur balance section on the Analysis sheet to ensure
3-22 • The User Interface
Aspen FCC 12.1 User Guide
that the sulfur distribution among the product cuts appears
reasonable.
Param Sheet - Heavy Liquid Product Streams for Simplified Main
Fractionation Parameterization
The properties for the gasoline stream include research and motor
octane numbers, PONA breakdown, Reid vapor pressure, and
volume percent concentration of C4’s. Regardless of how the
front-end part of the gasoline cut was specified on the Options
sheet (that is, constant RVP or constant C4), both are required
inputs for Parameter cases only. In Simulation cases, the constant
property controls the cut while the other property is calculated
when the problem is solved. The cloud point for the LCO cut is
also an input. The Conradson carbon and basic nitrogen results
reported for the heavy naphtha, LCO, HCO, and Bottoms affect
incremental conversion of these recycle streams.
The input data required is straightforward. The data required for
the Input TBP 90% cells is the target TBP 90% point. Contact
Aspen FCC 12.1 User Guide
The User Interface • 3-23
AspenTech to change the target to another distillation type such as
D86 90% or D86 End Point.
Catalyst Data
The catalyst data section is used to specify the number and type of
fresh catalyst, ECAT data, and other catalyst related data such as
inventory, make-up rate, and loss rates. Up to five different types
of fresh catalysts can be specified and one ZSM-5. The catalyst
type is selected from the combo box option. The library of
different catalyst types is found on the CST Factors sheet, which
is hidden in the install kit spreadsheet.
To View the CST Factors Sheet:
• On the toolbar, click Format | Sheet | Unhide | CST Factors.
After a catalyst type is selected, the actual composition and base
composition for the zeolite, alumina, and rare earth appear below
the combo box. Initially, they will be the same. If the actual values
differ from the base values based on vendor specifications, then
enter your values in the appropriate cells under the Actual
composition heading.
Fresh catalyst data copied from the CST Factors sheet is also
displayed below each catalyst type. Although these values are
constants and are highlighted in blue, do not enter any information
in these cells. They are simply included to ensure that the data
entered below in the ECAT section is consistent with the fresh cat
data.
Regardless which option has been selected for the catalyst activity
(MAT constant or make-up rate constant), the make-up rate is
always an input on the Param sheet. The cat inventory to enter is
the total inventory of catalyst in the regen/reactor circuit.
The cat losses in the regen flue gas and the reactor overhead are
also specified in this section. The model calculates the catalyst
withdrawal based on the difference between the make-up rate and
the cat losses. For those FCC units running low metals feed and/or
those with little or no catalyst withdrawal, set the cat losses to a
very low number. (Set regen cat losses at ¼ of make-up rate and
reactor cat losses at 1/10 to 1/20 of make-up rate) to ensure model
robustness. Otherwise, problems may occur in performing metals
calculation when comparing the difference between the metals
entering the unit with the feed, and the metals content in the regen,
in the losses and in the withdrawal.
The ECAT data entered must be consistent with the blended fresh
catalyst data. For example, if the lab ECAT activity is entered as
75%, while the blended fresh cat data has a lower activity value,
then the model will not solve due to this data inconsistency. The
FINES data corresponds to the catalyst impurities in the loss
3-24 • The User Interface
Aspen FCC 12.1 User Guide
catalyst streams leaving the regenerator flue gas and reactor vapor
line. The FINES data is normally not known, so it is recommended
to enter this data in a ratio consistent with the default ratios
between the ECAT and FINES data.
Param Sheet – Catalyst Data
Mechanical Data
The physical length, diameter, and height of the key reactor and
regenerator equipment are defined in this section. The equipment
layout is based on the typical side-by-side FCCU design. The riser
section is divided into four principal blocks as shown below. The
kinetic reactions take place in the VRISER1 and VRISER2
blocks, with some reaction taking place in the RXDIL block. The
riser outlet temperature specified as the first input in the Key
Operating Data refers to the vapor temperature of the
hydrocarbons leaving the RXDIL block.
The physical dimensions of VRISER1 and VRISER 2 are normally
straightforward to specify. General rules are that the bottom of
VRISER1 is normally taken at the bottom feed nozzle, while the
Aspen FCC 12.1 User Guide
The User Interface • 3-25
top of VRISER2 is normally taken at the top of the riser where the
vapors exit the riser section.
Determining how to divide the riser between these two extremities
for setting the length of VRISER1 and VRISER2 is dependent
upon the physical layout of the riser. If the riser has two active feed
injection points, then the length of VRISER1 can be taken as the
vertical length between the two injection points, and the length of
VRISER2 can be taken as the distance from the upper injection
point to tip of the riser where the vapors exit. If there is only one
injection point, then the riser can be divided in such a way that it
best matches changes in the internal diameter. If the internal
diameter changes within the selected length of VRISER1 and/or
VRISER2, then use the weighted average as the diameter.
In specifying the lift riser length, a measurement is taken between
the bottom of the riser and the injection point of the bottom feed
nozzles. The height of the reactor dilute block is dependent upon
the desired residence time of the vapors leaving the tip of the riser
and the entry of the secondary reactor cyclones. Enter the actual
diameter of the reactor for the diameter field, and vary the height
until the residence time matches acceptable results. The residence
time is found on the Analysis sheet. Its value, along with all data
on the Analysis sheet, is valid after running a Parameter,
Simulation or Optimization case.
RXDIL
Dilute Phase
(reaction)
-Adjust Hrx for residence time of 0 to 1 sec, but can
be more for some FCC designs.
-Can bypass solids (default is all solids to RXDIL)
R2
VRISER2
(reaction)
-Select length to best match physical layout of riser.
-If diameter changes in R2, use weighted average.
Dispersion Steam to R2
R1
- Fresh Feeds (1 to 10)
- Recycles: HN,LCO,HCO,Bot
Dispersion Steam to R1
- Lift Steam
- Lift Gas
Lift
Riser
VRISER1
(reaction)
-Select length to best match physical layout of riser.
-Bottom of R1 is main feed nozzles.
-If diameter changes in R1, use weighted average.
Lift Riser
(no reaction, enthalpy and dP effects only)
-Select length from bottom of riser to feed nozzle.
Residence Time of R1+R2
should be 2 to 5 sec
Regen Catalyst
Riser setup in AspenFCC
All pieces of equipment requiring an outer diameter and a wall
thickness can be input in various ways. If the metal thickness is
ignored, then the outer diameter should be taken as the internal
3-26 • The User Interface
Aspen FCC 12.1 User Guide
diameter plus two times the refractory thickness, and the wall
thickness should be set equal to the refractory thickness. This is
how the drawing is represented below. If the metal thickness is to
be included, then the outer diameter is equal to the internal
diameter plus two times the metal thickness plus two times the
refractory index, while the wall thickness is set equal to the metal
thickness plus the refractory thickness.
ODRx
HRx
wtRx
DStrip
ADStrip
DDilute
wtSC,SP
LStrip
Steam
LR2
ODSC,SP
ODSC,TR2
HCyclone Inlet
HB
Dinterfacial
SP SC
wtSC,TR2
wtR2
ODR2
TR1 SC
TR2 SC
DB
wtRC,SP
wtR1
ODRC,SP
SP
ODR1
ODRC,TR2
wtRC,TR2
RC
TR1
RC
TR2
wtLR
ODLR
RC
Drawing of Reactor/Regen for Mechanical Data
Where:
Aspen FCC 12.1 User Guide
Symbol
Equals
TR
SP
SC
transfer line
stand pipe
Spent Cat
LR1
The User Interface • 3-27
LLR
RC
Rx
Regen Cat
reactor dilute phase
The stripper diameter is to be taken as the entire internal diameter
of the reactor stripper model. The annulus diameter is taken as the
riser inner diameter in the stripper section, plus the corresponding
layers of refractory in the stripper, metal thickness of the riser, and
refractory thickness in the riser. If the FCC design has an external
riser, then set the annulus diameter to zero. Entering exactly zero is
valid.
For the spent cat route and the regen cat route, ignore transfer line
1 and set it to an arbitrarily short length (0.1 ft). Its outer diameter
and wall thickness should be set equal to the standpipes. Do not
enter values for the angle input required for the lift riser, spent cat
transfer lines, and regenerated cat transfer lines. Leave these at
their default values.
The regen bed height is adjusted to get the correct cat inventory
number in the regenerator. The interfacial diameter is normally set
equal to the regen bed diameter. Set the height of the inlet of the
regenerator cyclone equal to the length from the first stage cyclone
inlet to the bed level, plus the length from the bed level to the air
grid. Since the inlet of the first stage cyclone is normally
rectangular in shape, the diameter is calculated by first summing
up the total inlet area of all inlet first-stage cyclones, and then
calculating the diameter of a circle with this area (A = π d2/4).
The default settings for the fluidization media are typically
acceptable, but you can adjust these settings.
Param Sheet – Mechanical Data
3-28 • The User Interface
Aspen FCC 12.1 User Guide
Heat Losses
The heat loss terms are entered in this section.
Note: Heat losses in Riser1 and Riser2 must be entered as negative
values.
Param Sheet – Heat Losses
Tuning Data
Aspen FCC 12.1 User Guide
Tuning data is entered in this section. Each entry has a short
description to explain how the data can be adjusted. The most
relevant tuning parameter is for adjusting the overcracking peak
and the stripper performance. This section is geared toward
advanced users. For detailed procedures, refer to Heat Balance
Tuning.
The User Interface • 3-29
Param Sheet – Tuning Data
Analysis Worksheet
Sections
This sheet gives an overview of all the key process variables. This
sheet is divided in many different sections. Each section represents
some important part of the process such as, mass balance, sulfur
balance across the FCC, and so on. For each section, the
description of the variable and its title, specs, units, and values are
displayed.
Description
Row #
Mass balance
Displays the error in the mass balance between the feeds and
products
Fractionated products
Displays a detailed distribution of products on the volume
percent basis of fresh feed
Standard cut products
Displays a TBP or square cut distribution of products on the
volume percent of fresh feed
Sulfur balance
Displays the distribution of Feed sulfur in products
Feed rate summary
Displays the total fresh feed, total recycle feed and total feed to
riser on volume and mass basis
Fresh feed conversion
Displays the apparent and standard conversion on volume and
weight percent based on fresh feed
Aromatic contents
Displays the total aromatic content of each of the individual
feed
Heat balance - General
Displays general information about the coke yield, coke heat of
Information
combustion, Regen cooler and bed coils duty, catalyst
circulation rate etc.
Heat balance - Heat of cracking Displays information about the Apparent and theoretical heat of
cracking for total fresh feed and total fresh feed and recycle
combined
Sources of coke
Displays sources of coke distribution by mechanism of
3-30 • The User Interface
Aspen FCC 12.1 User Guide
3
18
36
49
59
67
75
87
102
112
formation and associated hydrogen content, Concarbon to feed
coke ratio, Metals coke factor, Riser feed mix conditions, and
key parameters.
Displays the 19 lump composition of the total feed on weight
Total feed composition
(Fresh+recycles)
percent basis.
Composition by boiling range Displays breakdown of 19 lumps by boiling range from C1-C4,
C5 – 430, 430-650, 650-950, and 950+.
Composition by type
Displays breakdown of components on basis of chemical
composition like C1-C4, C5 – 430, Paraffins, Naphthenes, 1, 2
&3 Ring aromatic cores, and Aromatic side chains. It has
various types of distribution combining various ranges of cuts
like distribution of 430+ paraffins, 650+ Naphthenes etc.
Vapor residence times
Displays vapor residence time distribution in Riser1, Riser2,
Reactor dilute phase section and total residence time.
Solids residence times
Displays solid residence time distribution in Riser1, Riser2,
Reactor dilute phase section and total residence time.
Riser/reactor catalyst inventory Displays solid hold up in tons of mass in the Riser1, Riser2,
Reactor dilute phase section and total solids hold up
Riser superficial velocities
Displays vapor velocity and the inlet and outlet of Riser1 and
Riser2 section
Regenerator data
Displays various key parameters of the regenerator section like
bed temperature, flue gas temperature, flue gas CO/CO2 dry
content, Coke on regen and spent catalyst etc.
Regenerator air supply
Displays rates for dry air, wet air, Enriched O2, and Enriched
summary
Air on mole, mass, and volume basis. It gives temperature and
pressure for each of the following streams. It provides molar
composition of wet and enriched air.
Metals Data
Displays the distribution of various metals like Ni, Va, Fe, Cu,
and Na and overall balance of these metals
Feed Blends
Worksheet
Aspen FCC 12.1 User Guide
This worksheet displays detailed data for all the fresh feed, the
blended feed, the recycle feed and the total blend of fresh feed and
recycle feed. This sheet is updated from load file and from any of
the last runs. You cannot enter any data on this sheet. The sheet
can be read in a matrix form with the columns as different feeds
and the rows as the various feed properties. Each feed property
variable is described in Column A below the heading Description.
Columns following this column display Titles, Specs, and Units
for the Feed1. Usually all the fresh feeds have the same
corresponding titles, the same specs, and the same units as Feed1.
The model can blend up to ten fresh feeds and up to four recycles
for the final blend to the riser. Fresh feed blends in Column O
represent the properties of all the fresh feeds blended. The four
recycles include recycles from:
The User Interface • 3-31
160
181
188
236
243
250
257
263
287
337
•
•
•
•
Heavy Naphtha
LCO
HCO
Bottoms
The final total blend is the actual model feed to the riser.
The various properties of the feed displayed are listed below:
Feed Properties
Description
Row #
Volume rate
Mass rate
Preheat temp to riser
Fraction of flow to bottom of
riser
Recycle vs. product splitter
ratio
Index number for feed type on
feed input sheet
API gravity
Specific gravity 60F/60F
K Factor based on D1160
VABP
D1160 VABP
Displays the volume flow rate of the feed
Displays the mass flow rate of the feed
Displays Preheat temperature of the feed to riser
Displays fraction of each feed that goes to the bottom of the riser
12
13
14
15
Displays the split ratio for each of the recycle streams.
16
Displays the corresponding feed type from the feed input page
row # 3
Displays the API gravity for the fresh feed
Displays the specific gravity for the fresh feed at 60F
Displays the UOP characterization factor based on D1160
VABP
Displays D1160 Volume Average Boiling Point in oF for the
feed
K Factor based on D2887 50% Displays the UOP characterization factor based on D2887 50%
point
cut point
Sulfur content
Displays the weight percent of the sulfur in fresh feed
Sulfur crackability factor
Displays potential amount of total sulfur in the feed that can be
cracked
Basic nitrogen content
Displays the basic nitrogen content of the feed in PPMW units
Basic/Total Nitrogen ratio
Displays the ratio of Basic to Total nitrogen in feed
Total nitrogen content
Displays the total nitrogen content of the feed in PPMW units
Conradson carbon content
Displays the weight percent carbon residue by ASTM test
(CCR) & Ramsbottom carbon procedure
content (RCR)
Metals content
Displays metal contents for Ni, Va, Fe, Cu and Na in PPMW
Refractive index from lab
Displays Refractive Index from the lab and also provides
estimated value of RI by model at 20o C
Viscosity Cst at 210F from lab Displays Viscosity of the Feed Stock
Aromatic content bias
Displays the difference in the amount of aromatic carbon
content between TOTAL Correlation and base fingerprint Ca
content based on base bulk properties
Aromatics content by modified Displays total aromatic carbon content by TOTAL correlation
Total method
based on actual feed
3-32 • The User Interface
Aspen FCC 12.1 User Guide
18
19
20
21
22
23
24
25
26
27
28
29
31
38
43
47
48
% of blended fresh feed
aromatics in each feed
Hydrogen content
% of blended fresh feed H in
each feed
Molecular weight
Distillation data
Base 19 lump composition
Final adjusted 19 lump
composition detail
Final adjusted 19 lump
composition by boiling range
Final adjusted 19 lump
composition by type
Final adjusted 19 lump
composition by type
Final adjusted 19 lump
composition by type
Cat Blend Worksheet
Displays the percentage of aromatic carbon from each fresh feed
to form blended feed
Displays the total elemental hydrogen content in the feed
Displays the percentage of hydrogen content from each of the
fresh feed to form blended feed
Displays the average molecular weight
Provides distillation curve data by D1160, D86 , D2887 and
TBP calculations
Provides weight percent of the base 19 lumps for the fresh feed
Provides weight percent for the final adjusted 19 lumps after the
manipulations by feed adjust model for the fresh feed
Gives breakdown of 19 lumps by boiling range from C1-C4 , C5
– 430, 430-650, 650-950 and 950+ lump
Gives breakdown of components on basis of chemical
composition like C1-C4, C5 – 430, Paraffins, Naphthenes, 1, 2
&3 Ring aromatic cores and Aromatic side chains.
Displays same data as above but with total of Ring Aromatics
cores composition.
Displays same data as above but with total of Aromatics
composition
Displays set of information about various biases for WABP, RI,
viscosity, various cuts and various ratios and methyl groups.
49
50
51
52
53
90
111
132
139
149
157
165
This worksheet displays detailed data for all the fresh catalyst,
ZSM-5, the blend used for make up, and the equilibrium catalyst.
This sheet is updated from the load file and from any of the last
runs. You cannot enter any data on this sheet. The sheet can be
read in a matrix form with the columns as different catalysts and
the rows as the various catalyst properties displayed.
Each feed property variable is described in Column A under the
heading Description. The Columns following this column display
Titles, Specs, and Units for Catalyst1. Usually all the fresh
catalysts have the same corresponding titles, the same specs, and
the same units as Catalyst1. The model can blend up to five fresh
catalysts, and ZSM-5 can be blended for the final catalyst blend
used in the make-up catalyst.
The blended catalyst properties used in the make-up are given in
Column K. The equilibrium catalyst properties are given in column
L.
Catalyst Properties
Description
Index no. from CST factors
sheet
Input mix percent
Displays the index number corresponding to the catalyst selected 11
from CST sheet row #2
Displays the percentage of the particular catalyst including
12
Aspen FCC 12.1 User Guide
Row #
The User Interface • 3-33
Normalized mix percent
Flowrate
MAT activity
Zeolite surface area
Matrix surface area
Total surface area
Metals contents
Composition shifts
Simulation
Worksheet
ZSM5 in the blended catalyst mixture
Displays the percentage of the particular catalyst excluding
ZSM5 in the blended catalyst mixture
Displays the mass flow rate of the catalyst
Displays the MAT activity for the catalyst
Displays the Zeolite Surface area
Displays the Matrix Surface area
Displays the total surface area of the catalyst
Displays the absolute content of Ni, Va, Fe, Cu and Na present
in the catalyst
Displays the composition shifts in zeolites, alumina and rare
earth metals to affect the catalyst factors
Displays catalyst factors for adjustments in yield, selectivity,
deactivation etc.
This sheet is separated into five sections:
• KEY OPERATING DATA
• FEED DATA
• YIELDS
• CATALYST DATA
• PRODUCT PROPERTIES
Typically, you enter data into the cells highlighted in blue for each
section. However, these highlighted cells are dependent upon the
options selected. Thus, if you modify options prior to running a
simulation case, you can update the cell colors with by clicking
AspenFCC | Development Tools | Update Simulation Sheet
Color.
Key Operating Data
The KEY OPERATING DATA section contains key values that
may be either input to or output from the model. You can input
changes to:
• Riser outlet temperature.
• Flue gas composition.
• Coil duties.
• Cooler duties.
• Flue gas quench rate .
• O2 injection rate .
If the model is being run for complete combustion, enter the O2
content of the flue gas.
If the model is being run in partial combustion mode, enter the CO
content of the flue gas, CO2/CO ratio in the flue gas, or regen bed
3-34 • The User Interface
Aspen FCC 12.1 User Guide
13
14
15
16
17
18
19
25
35
temperature, depending on the regenerator control option selected
on the Options sheet.
Simulation Sheet – Key Operating Data
Feed Data
The FEED DATA section contains inputs for up to 10 feeds. You
can specify recycle streams of heavy naphtha, LCO, HCO, and
bottoms separately. You can specify separate flow rates for each
feed. However, only the preheat temperature for the combined feed
may be specified. For each feed you can select the feed type using
the combo-box associated with that feed. Once the feed type has
been selected, you should input all of the analytical data for that
feed including API gravity, sulfur content, basic nitrogen content,
Conradson carbon content, refractive index, viscosity, and
distillation. You can choose to have the refractive index estimated
rather than using a measured value by selecting the Estimate option
in the refractive index combo-box. You can choose to enter
viscosity in either cSt or SUS, or have this value estimated also by
choosing the appropriate option in the viscosity combo-box for
each feed.
In addition to entering the 9-point distillation for each feed, you
must specify the distillation type (D86, D1160, D2887, or TBP) by
selecting the appropriate item from the distillation combo-box.
Finally, enter the feed metals data for each feed.
Aspen FCC 12.1 User Guide
The User Interface • 3-35
Simulation Sheet – Feed Data
Yields
3-36 • The User Interface
The YIELDS section contains only model output and thus you do
not enter any information in this section. Yields are reported on a
Standard basis and on a Fractionated basis. The Standard yields
represent the yields of each component or pseudo-component as if
the fractionation were perfect. For example, the C5+ Gasoline
yield in the Standard Grouped Yields subsection would contain
all of the C5’s and all components that boil below 430ºF. It would
contain no C4’s or lighter and no components that boil above
430ºF. The Gasoline yield in the Fractionated Grouped Yields
subsection would include a small amount of C4’s (the amount
necessary to match the C4’s specification or the RVP
specification) and also some amount of heavier material. Similarly,
some C5’s would appear in the C4 stream and some of the material
that boils below 430ºF would appear in the LCO stream.
Aspen FCC 12.1 User Guide
Simulation Sheet - Yields
Catalyst Data
Aspen FCC 12.1 User Guide
The CATALYST DATA section lets you change catalyst types
and catalyst properties, by selecting them from the appropriate
combo-boxes, to see how they will affect yields and conversions.
You can select up to five catalysts and one ZSM-5. For each
catalyst, there is a base value for zeolite content, alumina content,
and rare earth content. If the actual values differ from these base
values, you can enter these values in the appropriate cells. You can
also enter the catalyst make-up rate or the fresh MAT activity
depending upon the option selected on the Options sheet.
The User Interface • 3-37
Simulation Sheet – Catalyst Data
Product Rates and
Properties
3-38 • The User Interface
The PRODUCT RATES AND PROPERTIES section is used
primarily for reporting, but you can specify the cut points used for
the fractionation of the gasoline and LCO product streams.
Standard cut product properties are also reported.
Aspen FCC 12.1 User Guide
Simulation Sheet – Product Rates and Properties
LP Vectors Worksheet
The LP Vectors worksheet provides the results for LP vector runs.
The main purpose of generating LP vectors is to provide shift
factors for LP planning and scheduling tools, such as PIMS.
Generating LP vectors is a two-step process.
1 Specify the independent and dependent variables.
2 Run the LP vector generation command.
The instructions for running the LP vectors are at the top of the
worksheet. Select the independent and dependent variables from
the pick list when you set up the model for LP vector runs. The
independent variables are reported in columns and dependent
variables are reported in rows. You can select as many variables as
are available in the pick list. For each variable, attributes such as
name, units of measurement and base values are displayed, and the
cells are highlighted by dark blue color.
Before setting up the LP vector run, some default variables in the
Jacobian matrix are selected and the values of derivatives are
displayed. After you select the variables for an LP vector run, the
cells become empty. After the run, the values of the derivatives are
displayed in the cells with blue color.
Setting up LP Vectors
Generating LP vectors is a two-step process:
1 Specify the independent and dependent variables.
2 Run the LP vector generation command.
To set up the LP vectors of interest:
1 Select the AspenFCC | Setup Cases | Vectors menu
command.
Setup Cases | Vectors Command
Aspen FCC 12.1 User Guide
The User Interface • 3-39
The LP Vectors spreadsheet appears, along with a dialog box from
which you can specify the independent and dependent variables.
Setup LP Vectors Dialog Box
2
In the top list box, select the independent variables. You can
select any or all of the variables listed. Select the checkbox
beside the variable description to select a variable. Clear the
checkbox to deselect a variable.
3 In the lower list box select the dependent variables and
functions in the same way.
4 Once the independent and dependent variables have been
selected, click OK. The LP Vectors sheet will be cleared.
Then the independent variables will appear in Row 7 and the
dependent variables will appear in Column C. If you click
Cancel, the dialog box will close and no changes will be made
to the LP Vectors worksheet.
5 Save the worksheet to retain the changes made to the LP
Vectors page.
3-40 • The User Interface
Aspen FCC 12.1 User Guide
PIMS Vectors
Workshet
The PIMS Vectors worksheet is set up similarly to the LP Vectors
page, but is set up in such a way as to generate a generic PIMS
Table.
PIMS Table
Worksheet
A standard PIMS table which is generated using the data on PIMS
Vectors page. This page will typically have been set up by
AspenTech service personnel.
Generating a PIMS Table
Cases Worksheet
Aspen FCC 12.1 User Guide
To Generate A Simple Pims Table:
1 Input the data.
2 Run a simulation case with the appropriate specs:
• Fresh Feed Gravity basis should be SG
• Riser Temperature Control should be Riser Outlet
Temp
• Distillation for the feed should include &All.
3 Run a simulate case with the VABP option.
4 Generate PIMS vectors with the independent variables and the
dependent variables specified in the FCC PIMS table.
• All yields are on a fractionated basis
• H2 to Ethane from the detailed yields
• C3 and higher from the grouped yields
• C4s include C5 in LPG
• C3 olefin calculated by dividing C3 olefin by total C3
• C4 olefin are summed in the detailed yields and divided by
the grouped C4 + C5
• IC4 is divided by the C4+C5 total
• Sum of C5s are divided by C4 + C5 total
• Conversion is observed volume percent (E19 on
Simulation page)
• Generate sensitivity vectors
5 Make the appropriate transformations of the results to generate
the PIMS table.
• Multiply yields by –1
• Calculate changes in C3= of C3 Mixture by chain rule.
The Case Studies are a user-specified series of Simulation Cases.
You can vary independent variable values between cases.
Specifications cannot be varied between cases.
The User Interface • 3-41
The heading of the Cases worksheet provides the instructions to
carry out the case studies. The Cases worksheet is divided into
three sections from top to bottom.
The first section contains the independent variables that you want
to vary.
The second section shows the dependent variables to be reported.
You can select as many variables as are available in the pick list.
For each variable, attributes like name, units of measurement, and
base value of the variable are displayed and the cells are
highlighted in a dark blue color.
The third section shows the LP vector run for each of the cases
with the same dependent and independent variables.
For each case study run, the creep steps can be changed on Row 8
depending on the change in the values of variable. By default, all
the cases have a creep step value of 10.
Row 111 shows a convergence flag for each case run. The value
for convergence is 1 if the run succeeds and 0 otherwise. You can
run a maximum of 100 cases. Cases can be run from and to any
case number.
The case study should not necessarily start from case numbered 1.
Before the case study is set up, the columns are filled with either
the defaults selection of variables or the previously run data. After
the selection of the independent and dependent variables, the cells
in light blue can be changed to enter the value of the variables for
each case run in the independent variable section. After the case is
run, all the cells of the dependent variables also are highlighted
with light blue color. If any data is left over from previous run, you
must delete it manually.
Optimize Worksheet
The Optimization case varies a defined set of independent
variables to maximize (or minimize) a specified dependent
variable, the Objective Function. Use the Optimize worksheet to
set up the optimization variables and any bounds that are necessary
for solving optimization.
The sheet has two sections:
• Independent or manipulated variables
• Dependent or constraint variables
You select these variables from the pick list when you set up the
optimization problem.
For independent variables, the attributes provided are:
• Name
• Units
3-42 • The User Interface
Aspen FCC 12.1 User Guide
•
•
•
•
•
•
Upper bound
Lower bound
Step bound
Initial value
Optimized value
Specification of the variable
For dependent variables the attributes provided are:
• Name
• Units
• Upper bound
• Lower bound
• Initial value
• Optimum value
After you have selected the independent and dependent variables,
you can change the bounds on the variables to fit your
requirements.
After the optimization run, cells in red indicate that the bound for
that variable was reached.
You cannot change the initial value column. You can only change
cells highlighted in light blue, such as upper, lower and step
bounds for independent and dependent variables.
Profit Worksheets
There are three profit function sheets available to define the
objective function for the optimization run. At the top of each sheet
are notes about the definitions of profit objective function. The
sheet is divided into four sections: the first section is about the
main variables or properties. The other three contain the
incremental properties for each of the main variables or properties.
You can define only three incremental properties for each variable.
You can select up to a maximum of 50 variables for the profit
function. For each variable selected, its name, units and, price units
are displayed.
You must enter the price for the property selected under the
column labeled Price. Ensure that the price units for the properties
are defined. For each variable, you can enter a user label for
convenient reference.
Note: The price entered is positive for the products and negative
for the costs.
Do not leave the Price column blank. If there is no cost, enter zero.
For the incremental property, enter Base value and Price.
Aspen FCC 12.1 User Guide
The User Interface • 3-43
Profit Report
Worksheets
Profit report functions sheets provide the result of the optimization
run. Each of the profit functions has a corresponding profit report
sheet. Each of the profit report pages has three sections:
• Initial Values
• Results from Optimization
• Results from Simulation
The list of variables from the corresponding profit function page is
listed from Row 15 down. The incremental property is in the same
list but is indented below the parent property. Each section has a
Run Time and Status bar to record the time when that section was
last updated and what type of run it was. The initial section of the
worksheet is updated after a parameter run. All the cash flows are
converted to a time basis of per day, so any variable having a
different time basis on the Profit function sheet would be
converted to per day basis for reporting. All the cash flows for feed
are reported in red and for products in blue text.
Results from Optimization is updated after the optimization
problem run. Results from Simulation is updated after the
simulation run. The overall look of these sections is the same as
the Initial Values section described above.
The change in the values of cash flows due to parameterization and
optimization runs is reported in the Changes section next to the
Results from Optimization section. The change in the values of
cash flows due to parameterization and simulation runs is reported
in the Changes section next to the Results from Simulation
section. At the bottom of the sheet overall cash flows are reported
for:
• Feed cost
• Product revenue
• Total profit
Losses are reported as negative profits.
Hidden Worksheets
There are several worksheets in the Aspen FCC workbook that are
by default hidden. These are not needed for general use of the
workbook, but you can view them for information content.
To View These Worksheets:
• On the Excel menu bar, select Format | Sheet | Unhide.
Some of these worksheets are password protected to prevent
inadvertent changes to their contents. Such changes can affect the
functionality of the workbook and cause a failure to occur in this
functionality.
3-44 • The User Interface
Aspen FCC 12.1 User Guide
Hidden Worksheets
No
Worksheet Name
Description
1
2
Param IO
Param Links
3
4
5
Param UserInput
Analysis IO
Analysis Links
6
7
Feed Blends IO
Feed Blends Links
8
9
Cat Blend IO
Cat Blend Links
10
11
Simulation IO
Simulation Links
12
13
14
15
16
Simulation UserInput
Feed Input
CST Factors
EB Scripts
ReceiveVars
17
SendVars
18
Registry
19
ComboRegistry
20
Combo Table
Structures the layout for the Param worksheet
Direct cell links to the model variables available in the
workbook for the Param worksheet
Contains a copy of your input for the Param worksheet
Structures the layout for the Analysis worksheet
Direct cell links to the model variables available in the
workbook for the Analysis worksheet
Structures the layout for the Feed Blends worksheet
Direct cell links to the model variables available in the
workbook for the Feed Blends worksheet
Structures the layout for the Cat Blend worksheet
Direct cell links to the model variables available in the
workbook for the Cat Blend worksheet
Structures the layout for the Simulation worksheet
Direct cell links to the model variables available in the
workbook for the Simulation worksheet
Contains a copy of your input for the Simulation worksheet
Contains a library of feed fingerprints for different feed types
Contains a library of catalyst factors for different catalysts
Contains scripts for execution of the calculation engine
Contains and manages variables that are sent from the
calculation engine to the workbook through DCOM
Contains and manages variables that are sent to the calculation
engine from the workbook through DCOM
Contains a collection of data and parameters for the Aspen
FCC workbook
Contains and manages data about the combo box options in
the Aspen FCC workbook
Contains and manages the combo box tables that describe the
combo box options in the Aspen FCC workbook
Aspen FCC 12.1 User Guide
The User Interface • 3-45
3-46 • The User Interface
Aspen FCC 12.1 User Guide
CHAPTER 4
Specifying Data
Specifying Data
You can enter data on many different worksheets such as
Simulation, Param, etc. You can enter data either by:
• Selecting variables from the pick list for LP vectors
• Selecting values for Simulation and Parameter runs
• Changing specs by selecting different options
You can only change the data contained in blue cells. You can
select various options for the run from the Options worksheet.
However, you must immediately click the Update Spec Color
button on the Aspen FCC toolbar to see the cells on the Param or
Simulation sheets that can be changed during that run. See
Updating Spec Colors. on page 3-13.
To set up a Parameter case, enter data only in the Param
worksheet. Data on any other sheets is not used.
For Simulation runs, enter data only in the Simulation worksheet.
Data on any other sheets is not used.
For Case Studies, first select the independent and dependent
variables from the pick list. Then change the values of the
independent variables in the sections provided. You can also
change the creep iterations for each step.
For LP vector runs, you select the independent and dependent
variables. There is no data to be entered except selecting the
correct variables.
For Optimization runs, first set up the independent (manipulated)
variables and dependent (constraint) variables, then set up the
profit objective function. You can enter the data for bounds of the
variable on the Optimize worksheet in the blue cells. You can
enter the prices for the profit objective function variables on the
any of the Profit sheets, in the Price column. You can enter the
Aspen FCC 12.1 User Guide
Specifying Data • 4-1
price and base value for incremental properties in the Incremental
Properties columns.
Setting Up Case Studies
In addition to single cases, Aspen FCC lets you run multiple cases
at a time and retrieve the results into a single area that is easy to
work with. This can be useful if you want to see how the model
responds to changes in one or more variables. For example, it may
be desirable to see how the product yields vary with changes in
riser outlet temperature. To perform this type of study, you would
run multiple cases with different temperatures and have the results
reported. This can easily be accomplished by running a Case
Study.
Before You Start
Before running a Case Study, first ensure the model has been
initialized with a valid result from a Parameter case or a converged
Simulation case. With this as a starting point, review and, if
necessary, change the options in the Options and Simulation
worksheets. If you change any option, run a simulation to initialize
all the variable specifications before setting up the case study. The
options selected will determine which variables are available as
independent versus reported variables.
Any values entered on the Param or Simulation sheets will be
ignored when invoking the case study.
Note: When a new Case Study is set up or run, the data that are
currently in the worksheet are not automatically deleted. To
remove any unwanted data, you must select and delete the data.
Each step of the case study will typically require about one to two
minutes to solve and update the spreadsheet.
Specifying Varied and
Reported Variables
4-2 • Specifying Data
The next step is to specify which variables will be varied and
which variables will be reported.
1 Click AspenFCC | Setup Cases | Case Study.
The Cases worksheet appears, along with a dialog box from
which you can choose the independent variables that will be
varied and the dependent variables that will be reported.
2 In the upper list-box, select the variables that will be varied.
You may select as many variables as you want from the list by
selecting the checkboxes beside the variable descriptions. A
variable can be also be deselected by clearing its checkbox.
3 In the lower list-box, select (in the same manner) the variables
that will be reported on the Cases sheet.
4 Once you have selected all the variables, click OK to set up the
worksheet.
Aspen FCC 12.1 User Guide
The independent variable names will appear on the Cases
worksheet in Column A starting with Row 9. The report variables
will appear on the Cases worksheet in Column A starting with
Row 111. Column B is reserved for optional user labels.
Clicking Cancel will close the dialog box without making changes
to the Cases worksheet.
Setup Case Study Dialog Box
5
Aspen FCC 12.1 User Guide
Once the Cases worksheet is set up, enter values for the
independent variables for each case to be run.
Specifying Data • 4-3
Case Study Worksheet
The model is now ready to execute a Case Study.
Setting up Optimizations
Optimization maximizes or minimizes a user-specified objective
function by manipulating independent variables (feed stream,
block input, or other input variables.) The objective function is an
equation that is used by the optimization engine to determine the
manner in which to manipulate the degrees of freedom
(independent variable) in a problem. You may have more than one
objective function in a problem, but only one is used by the engine
during the solution. Objective functions for Optimize cases in the
FCC model are normally economic in nature (for example, they
might maximize operating profit or minimize operating cost)
Aspen Plus 12.1 supports three different kinds of objective
functions:
• Linear
• Sum of Squares
• Symbolic
Aspen FCC uses objective functions that are in symbolic form.
Independent Variables
4-4 • Specifying Data
Independent variables are variables whose values can be changed
independently, for example, the feed rate in the FCC unit. The
Aspen FCC 12.1 User Guide
optimizer can vary the values of independent variables to push the
values of the objective function in the defined direction (maximize
profit or minimize cost) until some bounds are reached. Each
independent variable accounts for a degree of freedom. The
number of degrees of freedom is equal to the number of
independent variables in an optimization run if no independent
variable is at its bound. You can impose upper and lower bounds
on independent variables to prevent the final solution from
deviating too far away from the starting point. You can also
impose step bounds on independent variables.
Bounds
Aspen FCC 12.1 lets you bound every variable in the problem as
shown below:
Xl < X < Xu
The step bound of an independent variable defines how much the
value of the variable can be changed in a single optimization run.
The step bound is used along with the initial value, lower bound,
and upper bound to compute the actual bounds to be used in the
run:
Xl = max(X - |Xstep|, Xlower)
Xu = min(X + |Xstep|, Xupper)
You should define upper and lower bounds for all independent
variables. You can also define the step bounds for independent
variables.
Most of the dependent variables in the FCC model have very wide
bounds, such as –1.E20 for lower bound and 1.E20 for upper
bound. However, some dependent variables have physical
meaning. You should set up appropriate bounds for them to
prevent the solution from getting into infeasible operating
conditions. For example, there is a metallurgic limit on regenerator
cyclone temperature. Hence, an upper bound should be set for this
variable. Only those constrained dependent variables must be
defined when setting up an optimization case in FCC model.
In general, it is not recommended to heavily bound an optimization
problem for reasons that are both practical and algorithmic.
Bounds on independent variables are recommended in order to
avoid unbounded problems. All other bounds should be used only
if they are absolutely necessary. The optimization engine for FCC
model is the DMO solver. For more information about the DMO
solver, refer to DMO Solver Background.
Setting up Objective
Functions
Aspen FCC 12.1 User Guide
To set up an objective function:
1 Select the AspenFCC | Setup Cases | Profit x menu command
where x is the number 1, 2, or 3.
Specifying Data • 4-5
Setup Cases | Profit 1 Command
A dialog box appears, listing the variables available to be used in
the profit calculation.
Add Variables to Objective Function Dialog Box
2
Select the principal variables to be used in the profit
calculation, then click OK.
The variables appear on the Profit sheet you selected in step 1.
3 To specify an incremental variable to adjust the principal
variable value, select the same AspenFCC | Setup Cases |
Profit x menu command.
4 In the dialog box, select any single principal variable, and then
click Setup Incrementals.
4-6 • Specifying Data
Aspen FCC 12.1 User Guide
Setup Incrementals Button
A second list of incremental variables appears.
5 Select up to three incremental properties; then click OK.
Add Properties to the Selected Product Dialog Box
The incremental variables appear on the selected Profit sheet.
6 After selecting all the principal properties and incremental
properties that comprise the objective function, enter a value
for each variable. For each principal property, the variable
Aspen FCC 12.1 User Guide
Specifying Data • 4-7
7
Setting up Optimization
Variables and Bounds
name, the units of the variable, and the units for the value will
appear. Enter the appropriate value in the Value column.
Take care to properly match units. For example, if a flow rate
is in thousands of barrels per day, the value entered must be in
dollars per thousand barrels. If you select a unitless variable for
the objective function, such as conversion, the value will also
be unitless.
Enter values for each incremental property. The Base is the
value at which the incremental property has no effect on the
principal property. All of the incremental properties are either
unitless or have a fixed unit type such as vol% aromatics.
In addition to setting up the objective functions used to optimize,
you must also set up the optimization variables and any bounds
that are necessary. For instance, you can choose to optimize Profit
1 by varying the feed rate of feed 1. However, the unit may have
constraints to how much wet gas can be processed, so the wet gas
volume would be selected as a dependent constraint variable.
The independent variables have the specification of Const if
optimization has never been set up before. However, not all
variables with Const specification in the model are included in
independent variable list. Only those variables that can be
manipulated in the FCCU will appear. Those variables are
identified by Opt in Column R (titled Opt) on the SendVars
sheet. The default list of independent variables should be able to
handle most optimization runs. If you want to use other variables
as independent variables, you should manually set up those
variables on the SendVars sheet.
After a variable is selected on the independent list, the
corresponding cell in Column V (titled Opt Select) on the
SendVars sheet will be set to YES for this variable. When solving
the optimization case, the variable will be sent to the Command
Line with the Optim specification. However, the SendVars still
keeps the original Const specification for this variable.
The dependent constraint variables have the specification of Meas
or Calc. However, not all variables with Meas and Calc
specification appear in the list. Only those variables that represent
operation constraints in the FCCU will appear. Those variables are
identified by Opt in Column R (titled Opt) on the ReceiveVars
page. The default list of dependent variables represents all
constraints commonly met in FCCU operation. If you have a
particular constraint that is not represented by any variable on the
list, you can manually set up those variables on the ReceiveVars
page. After a variable is selected on the dependent list, the
4-8 • Specifying Data
Aspen FCC 12.1 User Guide
corresponding cell in Column Y (titled Opt Select) on the
ReceiveVars page will be set to YES for this variable.
Aspen FCC displays only Const variables in the pick list for
independent variables and only Calc and Meas variables in the
pick list for dependent variables. This ensures that whatever set
you choose will lead to a well-posed problem.
To set up optimization variables and bounds:
1 Click AspenFCC | Setup Cases | Optimization as shown
below.
Setup Cases | Optimization Command
This will activate the Optimize worksheet and open a dialog box
from which you can select the desired independent variables (extra
degrees of freedom) and dependent constraint variables.
Aspen FCC 12.1 User Guide
Specifying Data • 4-9
Setup Optimization Case Dialog Box
2
To select a variable, select the checkbox to the left of the
variable name. Clearing the checkbox of a selected variable
will deselect the variable.
3 When the independent variables and the dependent constraint
variables have been selected, click OK to complete the setup.
The selected variables and their current values will then appear
on the Optimize spreadsheet. Clicking the Cancel button will
close the dialog box without making any changes to the
optimization problem. After setting up the optimization, a
message box will appear to remind you to Make sure the profit
function is defined before running the optimize case.
4 After selecting the desired independent variables and
dependent constraint variables, input lower and upper bounds
in Columns C and F by the appropriate variables. You can also
enter step bounds for the independent variables in Column G.
The optimization is now ready to solve.
4-10 • Specifying Data
Aspen FCC 12.1 User Guide
Variables on Optimize Sheet
5
Save the worksheet in order to save the changes made to the
Optimize pages.
The optimization problem is now ready to solve.
Setting Up LP Vector Calculations
In addition to letting you determine yields, temperatures, and
product properties, Aspen FCC can generate LP vectors.
Aspen FCC 12.1 User Guide
Specifying Data • 4-11
4-12 • Specifying Data
Aspen FCC 12.1 User Guide
CHAPTER 5
Running Cases
Case Types
You can run five types of cases in the Aspen FCC model:
• Simulation Case
• Parameterization Case
• Optimization Case
• Case Studies
• LP Vector Generation Case
The Simulation Case is a simple what-if study. What changes to
dependent variables result from a specified set of independent
variables?
The Parameterization Case fits the model’s kinetic rate constants
and base operating data to match an observed process operation,
feed properties, and product yields. This case is often referred to
generically as a calibration case.
The Optimization Case varies a defined set of independent
variables to maximize (or minimize) a specified dependent
variable, the Objective Function.
The Case Studies are a user-specified series of Simulation Cases.
You can vary independent variable values between cases.
Specifications can not be varied between cases.
The LP Vector Generation Case generates a set of derivatives
between specified dependent and independent variables that can
then be used in the formulation of LP vectors.
You can run all case types from either the FCC toolbar or the
AspenFCC menu.
Running Cases from the
FCC Toolbar
Aspen FCC 12.1 User Guide
From the FCC toolbar, shown below, you can select the type of
case to be run from the Case Type list (circled).
Running Cases • 5-1
•
Click the Run Case button beside it to begin execution of the
case.
Case Type List-Box
Running Cases from the
FCC Menu
You can also run cases using selections from the AspenFCC menu
as shown below.
• Click AspenFCC | Run Case | type of case to begin execution
of the case.
Run Cases | Simulation Case Command
Solver Settings
A script file embedded in the EB Scripts spreadsheet (hidden by
default) controls the execution of each case. For Aspen FCC, the
following solver settings are recommended for the simulation case
type.
solver settings maxiter = 50
solver settings miniter = 0
solver settings creepflag = 1
solver settings creepiter = 10
solver settings creepsize = 0.1
solver settings searchmode = 3
solver settings factorspeed = 1
5-2 • Running Cases
Aspen FCC 12.1 User Guide
solver settings pivotsearch = 10
solver settings rescvg = 1.E–10
solver settings objcvg = 1.E–6
solver settings HESSIANUPDATES = 0
For many Simulation cases, the creepiter variable can be reduced
to 5 or even lower, to converge the cases more quickly. However,
the default of 10 will allow the model to converge more robustly.
Key variables of interest to FCC users are:
Variable
Description
Maxiter
Miniter
Creepflag
Creepiter
Creepsize
Maximum number of iterations allowed for solution
Minimum number of iterations
Creep control flag: 0=off, 1=on
Number of creep iterations
Magnitude of steps as a fraction of the step size that would
be taken if the Creepflag were set to 0 (off)
Residual convergence tolerance
Rescvg
Running a Parameterization Case
Parameterization means calibrating (or tuning) the model to match
plant operating data. A simple example would involve one
measurement (a temperature) and one parameter (a heat exchanger
UA). The temperature would be entered into the model and the UA
would be calculated. Thereafter, when running simulation cases,
the UA would be constant and the temperature would be
calculated.
In Aspen FCC, parameterization involves entering plant operating
data, such as flows, temperatures, pressures, and properties, while
the model automatically calculates the kinetic rate constants and
other parameters required to match them exactly.
Typically, AspenTech would have executed a project which
included analyzing plant test run data and tuning Aspen FCC to
match the operating unit performance. The result of this project is
the delivery of a data file containing a parameterized Aspen FCC
case and a comprehensive training course. You should initialize
Aspen FCC using this data file. For information on loading a data
file, see Loading Data Files on page 2-4.
You will need to parameterize Aspen FCC again to better match
plant operations some time after the initial data file is delivered by
AspenTech. Many mechanical revamps affecting risers, feed
Aspen FCC 12.1 User Guide
Running Cases • 5-3
nozzles, and regenerator air grid make it necessary to reparameterize the model. Even when there has been no revamp,
routine mechanical wear can affect the contacting efficiency in the
riser and regenerator, and thus change the heat balance and yield
selectivity from the values at initial delivery.
Aspen FCC Options
The first step to running a parameterization is to select all the
appropriate options. Since the model was set up once already by
AspenTech, the options are probably already appropriate.
However, it is possible that a change in operating philosophy will
require changing one or more of the options.
The options are described in the following table:
Option Title
Option
Description
Feed Rate
Basis
Input volume
rates
Input mass
rates
Input API
Feed flow rates are entered on a volume flow basis
Fresh Feed
Gravity Basis
Input SG
K const for
LP
Ca const for
LP
H const for
LP
Product
Gravity Basis
Input API
Input SG
Light Ends
Product Basis
Input volume
rates
Input mass
rates
Heavy Product Input volume
Rate Basis
rates
Input mass
rates
Fractionation
Input vol,
Control
HN and HCO
rate const.
Input mass,
HN and HCO
5-4 • Running Cases
Feed flow rates are entered on a mass flow basis
Feed density is entered as API gravity
Feed density is entered as specific gravity (60/60)
Used for LP vectors only and should not be used for Parameter
cases. K factor and distillation are constant while gravity is
calculated.
Used for LP vectors only and should not be used for Parameter
cases. Feed carbon atom aromatic wt% and distillation are
constant while gravity is calculated.
Used for LP vectors only and should not be used for Parameter
cases. Feed hydrogen wt% and distillation are constant while
gravity is calculated.
For Parameter case, product density is entered as API gravity
For Parameter case, product density is entered as specific
gravity (60/60)
For Parameter case, product flow rates are entered on a
volume flow basis
For Parameter case, product flow rates are entered on a mass
flow basis
For Parameter case, product flow rates are entered on a
volume flow basis
For Parameter case, product flow rates are entered on a mass
flow basis
Product flow rates are entered on a volume flow basis. Heavy
naphtha and HCO flow rates are constant.
Product flow rates are entered on a mass flow basis. Heavy
naphtha and HCO flow rates are constant.
Aspen FCC 12.1 User Guide
rate const.
Input vol, all
use TBP90
Fresh Feed
Conradson
Carbon Basis
Fresh Feed
Basic or Total
Nitrogen
Regenerator
Control:
Complete
Combustion
option
selected
Input mass,
all use
TBP90
Input vol,
HN/LCO/
HCO rates
const
Input mass,
HN/LCO/
HCO rates
const
Input
Concarb
Product flow rates are entered on a mass flow basis. Heavy
naphtha, LCO, and HCO flow rates are constant.
Fresh feed Conradson carbon content is entered. Ramsbottom
carbon will be calculated based on the API conversion
method.
Input
Fresh feed Ramsbottom carbon content is entered. Conradson
Ramsbottom carbon will be calculated based on the API conversion
method.
Input Total N Fresh feed total nitrogen is entered. The basic nitrogen will be
calculated based on the factor entered for each feed (default
value is basic = 1/3 * total)
Input Basic N Fresh feed basic nitrogen is entered. The total nitrogen will be
calculated based on the factor entered for each feed (default
value is basic = 1/3 * total)
Flue Gas O2 Regenerator flue gas O2 content will be the target, the injected
const float air O2 rate is constant, and the air rate will be calculated. The air
vol
and injected O2 rates are entered on a volume basis for the
Parameter case.
Flue Gas O2
const float air
mass
Flue Gas O2
const float
O2 inj vol
Flue Gas O2
const float
O2 inj mass
Air and O2
inj const float
Flue Gas O2
Aspen FCC 12.1 User Guide
Product flow rates are entered on a volume flow basis. Heavy
naphtha and HCO flow rates will vary based on the entered
TBP 90% targets.
Product flow rates are entered on a mass flow basis. Heavy
naphtha and HCO flow rates will vary based on the entered
TBP 90% targets.
Product flow rates are entered on a volume flow basis. Heavy
naphtha, LCO, and HCO flow rates are constant.
Regenerator flue gas O2 content will be the target, the injected
O2 rate is constant, and the air rate will be calculated. The air
and injected O2 rates are entered on a mass basis for the
Parameter case.
Regenerator flue gas O2 content will be the target, the air rate
is constant, and the injected O2 rate will be calculated. The air
and injected O2 rates are entered on a volume basis for the
Parameter case.
Regenerator flue gas O2 content will be the target, the air rate
is constant, and the injected O2 rate will be calculated. The air
and injected O2 rates are entered on a mass basis for the
Parameter case.
Regenerator air rate and injected O2 rate are constant while
the flue gas O2 is calculated. The air and injected O2 rates are
entered on a volume basis for the Parameter case.
Running Cases • 5-5
Regenerator
Control:
Partial
Combustion
option
selected
Bed T & FG
O2 const
float Cat
Cooler & air
vol
Bed T & FG
O2 const
float Cat
Cooler & air
mass
Bed T const
float air vol
Regenerator flue gas O2 content and bed temperature are both
entered targets, the injected O2 rate is constant, and the air rate
and catalyst cooler duty will be calculated. The air and
injected O2 rates are entered on a volume basis for the
Parameter case.
Regenerator flue gas O2 content and bed temperature are both
entered targets, the injected O2 rate is constant, and the air rate
and catalyst cooler duty will be calculated. The air and
injected O2 rates are entered on a mass basis for the Parameter
case.
Regenerator bed temperature will be the target, the injected
O2 rate is constant, and the air rate will be calculated. The air
and injected O2 rates are entered on a volume basis for the
Parameter case.
Bed T const
float air mass
Regenerator bed temperature will be the target, the injected
O2 rate is constant, and the air rate will be calculated. The air
and injected O2 rates are entered on a mass basis for the
Parameter case.
Regenerator bed temperature will be the target, the air rate is
constant, and the injected O2 rate will be calculated. The air
and injected O2 rates are entered on a volume basis for the
Parameter case.
Regenerator CO2/CO ratio will be the target, the injected O2
rate is constant, and the air rate will be calculated. The air and
injected O2 rates are entered on a volume basis for the
Parameter case.
Regenerator CO2/CO ratio will be the target, the injected O2
rate is constant, and the air rate will be calculated. The air and
injected O2 rates are entered on a mass basis for the Parameter
case.
Regenerator CO2/CO ratio will be the target, the air rate is
constant, and the injected O2 rate will be calculated. The air
and injected O2 rates are entered on a volume basis for the
Parameter case.
Regenerator CO vol% dry basis will be the target, the injected
O2 rate is constant, and the air rate will be calculated. The air
and injected O2 rates are entered on a volume basis for the
Parameter case.
Regenerator CO vol% dry basis will be the target, the injected
O2 rate is constant, and the air rate will be calculated. The air
and injected O2 rates are entered on a mass basis for the
Parameter case.
Regenerator CO vol% dry basis will be the target, the air rate
is constant, and the injected O2 rate will be calculated. The air
and injected O2 rates are entered on a volume basis for the
Parameter case.
Bed T const
float O2 inj
vol
CO2/CO
const float air
vol
CO2/CO
const float air
mass
CO2/CO
const float
O2 inj vol
CO const
float air vol
CO const
float air mass
CO const
float O2 inj
vol
5-6 • Running Cases
Aspen FCC 12.1 User Guide
CRC const
float air vol
CRC const
float air mass
CRC const
float O2 inj
vol
Pressure
Balance
Control
Light Naphtha
Front-End
Control
All pressures
const
WG to RX
DP const
WG-RX and
RX-RGN DP
const
Input RVP
Input C4
Catalyst
Activity
Control
Riser
Temperature
Control
Input ECAT
MAT
Input makeup rate
Reactor
Plenum
Temp
Riser Outlet
Temp
Regen Cat
SV % &
Measured
Plenum
Temp
Regen Cat
SV % &
Measured
Plenum
Temp
Aspen FCC 12.1 User Guide
Carbon on regenerated catalyst wt% will be the target, the
injected O2 rate is constant, and the air rate will be calculated.
The air and injected O2 rates are entered on a volume basis for
the Parameter case.
Carbon on regenerated catalyst wt% will be the target, the
injected O2 rate is constant, and the air rate will be calculated.
The air and injected O2 rates are entered on a mass basis for
the Parameter case.
Carbon on regenerated catalyst wt% will be the target, the air
rate is constant, and the injected O2 rate will be calculated.
The air and injected O2 rates are entered on a volume basis for
the Parameter case.
Wet gas flash, reactor vessel, and regenerator vessel pressures
all constant.
Wet gas flash to reactor vessel delta pressure constant, and
regenerator vessel pressure constant.
Wet gas flash to reactor vessel delta pressure constant, and
reactor vessel to regenerator vessel delta constant.
The light naphtha (debutanizer bottoms) front end is
controlled by an entered RVP target.
The light naphtha (debutanizer bottoms) front end is
controlled by a C4 vol% target.
Equilibrium catalyst MAT activity is entered as the target,
fresh catalyst make-up rate is calculated.
Fresh catalyst make-up rate is constant, and the equilibrium
catalyst MAT activity is calculated.
Reactor Plenum Temperature is Constant, Riser Temp is
Calculated, Regen Cat SV % open and Spent Cat SV % open
are measurements.
Riser Temp is Constant, Reactor Plenum Temperature is
Calculated, Regen Cat SV % open and Spent Cat SV % open
are measurements.
Regen Cat SV % open is Constant, Riser Temp is Calculated,
Reactor Plenum Temp and Spent Cat SV % open are
measurements.
Regen Cat SV % open is Constant, Reactor Plenum Temp is
Calculated, Riser Temp and Spent Cat SV % open are
measurements.
Running Cases • 5-7
Spent Cat SV
%&
Measured
Plenum
Temp
Spent Cat SV
%&
Measured
Plenum
Temp
Entering Data for
Parameter Cases
5-8 • Running Cases
Spent Cat SV % open is Constant, Riser Temp is Calculated,
Reactor Plenum Temp and Regen Cat SV % open are
measurements.
Spent Cat SV % open is Constant, Reactor Plenum Temp is
Calculated, Riser Temp and Regen Cat SV % open are
measurements.
Select the appropriate options in the Options worksheet.
1 In the Options worksheet, select the appropriate options.
2 Change the blue highlighting of the data entry cells on the
Param and Simulate worksheets by clicking the Update Spec
Color button on the FCC toolbar. See Updating Spec Colors.
on page 3-13.
3 The next step is to enter all of the plant data highlighted in blue
on the Param sheet. The data is organized into the following
groups:
• Key Operating Data
• Feed Properties
• Preheat Temperature Control
• Product Data for Reactor Parameterization
• Product Data for Fractionation Parameterization
• Catalyst Data
• Mechanical Data
• Tuning Data and Factors
For more information about these sections, see Param
Worksheet. on page 3-16.
4 In addition to entering plant data, you must select some combo
box options. After selecting any of these options, click the
Update Spec Color button. See Updating Spec Colors. on page
3-13
The combo-boxes of most interest are described below:
• Feed Type: Feed types for feeds 1 through 10 must be
selected. Choose the feed type that most closely matches
the actual feed being processed in the FCC.
• Distillation Type: VABP D1160 should not be selected for
parameter cases. Selecting the TYPE & All options is not
as robust as selecting the TYPE options. If the parameter
case does not lead to a solution, try selecting just the TYPE
options for all feeds and products.
Aspen FCC 12.1 User Guide
•
Running the Parameter
Case
1
Feed Metals Option: The Enter feed metals option means
that reasonable feed metals analyses are available for all
feeds, or that you will enter zero for all feeds and ignore
feed metals effects. Calc feed X metals means that any
error in metals balance will be lumped into that one feed X.
Next, run the parameter case from the FCC toolbar or the
AspenFCC menu.
a. Ensure that Parameter appears
in box. If not, click small arrow to
open menu, and select Parameter
b. Click the start button to run the case.
Running a Parameter Case
2
Typical execution time is between one and three minutes
depending on the number of creep steps and how close to a
solution the model starts.
Finally, review the calculated results on the Analysis, Feed
Blends, and Cat Blend worksheets. A few areas of interest on
these sheets are the material balance, sulfur balance, heat
balance, detailed individual and blended feed compositions,
and individual catalyst properties. Once these data have been
reviewed and are satisfactory, the parameter case is complete.
Several sheets are refreshed to reflect the values that currently
reside in the model after a Parameter run is successfully solved:
• Param sheet
• Analysis sheet
• Feed Blend sheet
• Catalyst Blend sheet
• Simulation sheet
The Analysis sheet should be thoroughly reviewed after running a
Param case. Investigate any inconsistent or unexpected results
such as negative yields before conducting further studies with the
current data.
Aspen FCC 12.1 User Guide
Running Cases • 5-9
Once you have run and successfully solved the Parameter case, and
carefully reviewed the results on the Analysis sheet, save the data.
See Saving and Loading Data Files on page 2-3. Saving the data
lets you load this data at any time so that the starting point for
subsequent solutions will be a valid parameterization.
Running a Simulation Case
Once the model has been parameterized and satisfactorily tuned to
match plant responses, you can use the model to predict how
changes in feed rates, feed properties, and operational conditions
affect the yields and product properties. Typically, AspenTech will
have executed a project that included analyzing plant test run data
and tuning Aspen FCC to match the operating unit performance.
The result of this project is delivery of a data file containing a
parameterized Aspen FCC case and a comprehensive training
course. You should initialize Aspen FCC using this data file before
running a Simulation case. See Loading Data Files. on page 2-4.
1 Confirm the option selections made in the Parameter case. See
the section Aspen FCC Options. on page 5-4. Note that some
of these options are only applicable to Simulation cases.
2 Enter the new operating conditions, feed properties, or other
targets of interest on the Simulation worksheet. Note that any
values entered on the Param worksheet will be ignored for a
Simulation case. For more information about the data on this
sheet, see Simulation Worksheet. on page 3-34.
3 Set combo-box options available on the Simulation sheet has
See the Entering Data for Parameter Cases section on page 5-8
to review information about these options. The VABP D1160
option is now available. It should be used only after running a
Simulation case with the D1160 option or with one of the
TYPE & All options selected. Only then will the VABP D1160
option yield valid results.
After changing any option or combo-box on the Options sheet
or the Simulation sheet, click the Update Spec Color button on
the Aspen FCC toolbar to highlight the required data entry
cells. See Updating Spec Colors. on page 3-13.
4 Next, run the Simulation case from the AspenFCC toolbar or
the AspenFCC menu. See the sections Running Cases from the
FCC Toolbar and Running Cases from the FCC Menu. on page
5-2. Typical execution time is between one and three minutes
depending on the number of creep steps and how close to a
solution the model starts.
5-10 • Running Cases
Aspen FCC 12.1 User Guide
5
Finally, review the calculated results on the Analysis, Feed
Blends, and Cat Blend worksheets. A few areas of interest
include sulfur balance, heat balance, detailed individual and
blended feed compositions, and individual catalyst properties.
Once you have reviewed this data and find it satisfactory, the
Simulate case is complete.
Note: Once the simulation case has been run, save this data using
the Save Case Data command. This will let you load this data at
any time to use as a valid starting point for subsequent cases. See
Saving and Loading Case Data Files. on page 2-3.
Running Multiple Cases
In addition to single cases, Aspen FCC lets you run multiple cases
at one time and retrieve the results into a single area that is easy to
work with. This can be useful if you want to see how the model
responds to changes in one or more variables. For instance, it
might be desirable to see how the product yields vary with changes
in riser outlet temperature.
To perform this type of study, you would run multiple cases with
different temperatures and have the results reported. You can do
this by running the Case Study option.
Running the Case Study
Aspen FCC 12.1 User Guide
Before you run a Case Study, you must set up the data for the Case
Study. See Setting up Case Studies. on page 4-2.
1 On the Aspen FCC toolbar, select the Case Study option; then
click the run button.
-orSelect the AspenFCC | Run Cases | Case Study menu
command to run the case study.
Running Cases • 5-11
The Select Case Study Range dialog box appears
2
3
Enter the first and last cases to run, then click OK.
If you do NOT want to calculate LP Vectors, clear the
Calculate LP Vectors? option.
The Command Line window appears and the Case Study starts
with the first specified case.
After each case is solved, the Command Line window closes while
the data is loaded into the spreadsheet. The Command Line
window reappears as each subsequent case starts. While the
Command Line window is present, you can click Abort to stop the
case study. This stops the current run and subsequent cases that
were specified. For example, if you specified a run for cases 1
through 8 and you click Abort while case number 3 is being
solved, the model will quit solving case 3. In addition, cases 4
through 8 will not be solved.
For Case Studies, none of the data on other worksheets is updated.
After the independent variable data have been sent, the cells are
highlighted in blue. Similarly, after the reported variables have
been retrieved, those cells are highlighted in blue.
LP Vectors Option
5-12 • Running Cases
In addition to reporting values for all of the specified report
variables, a set of LP vectors can optionally be generated for each
case. These LP vectors will correspond to the LP vectors that have
been set up on the LP Vector worksheet. These will be reported in
the LP vector section of the case study page starting with row
1005. Column A lists the dependent variables and Column B lists
the independent variables. The values that are returned for a case
study will be highlighted in blue.
Aspen FCC 12.1 User Guide
Running an Optimization Case
Solving the Optimization
Before you run an optimization, you must set up the objective
function and the variables and bounds for the optimization. See
Setting up Optimizations. on page 4-4.
1 From the AspenFCC toolbar, select the Optimize option; then
click the run button.
-orFrom the AspenFCC menu, click Run Cases | Optimization.
The Select Objective Function dialog box appears.
2 Select an objective function. You select only one active
objective function.
3 Select the direction of the optimization by selecting Max (for
maximizing) or Min (for minimizing). If the objective function
is set up as a profit function, select Max. If the objective
function is set up as a cost function, select Min.
4 Select the profit reports to update. Normally only the active
objective function is selected.
Select Objective Function Dialog Box
5
Aspen FCC 12.1 User Guide
Click OK to complete the setup and send the data from the
Optimization spreadsheet to the model. Clicking Cancel will
close the dialog box and return to the Optimize worksheet.
Running Cases • 5-13
After you select an objective function, the Command Line window
appears.
Solving an Optimization Case
Changing the Behavior of To change the behavior of the DMO solver, click one of the
the DMO Solver
buttons at the bottom of the command window. Your selection will
take effect at the start of the next DMO iteration.
Click this
button
To
Abort
No Creep
Force the model to quit solving.
Take the DMO solver out of creep mode. Use this to expedite
solving when the current run is close to the final solution, in which
case both the Residual Convergence Function and the Objective
Convergence Function are small and close to convergence criteria.
Refer to Chapter 7 for more details on DMO solver.
Cause the model to close the residuals without minimizing the
objective function convergence. The Close Residuals button is
useful in cases where the objective function very nearly reaches a
maximum value but the convergence of the objective does not
close.
Close
Residuals
There is another button, Close, at the very bottom of the dialog
box. This button is disabled during the optimization run. It is only
active when no run is being executed. Clicking the Close button
will close the dialog box and return the Excel interface.
After the model solves the optimization, the solution values are
retrieved into the Optimization page and the spreadsheet is
updated. The corresponding report page, Optimize page, and
Simulation page are updated to the current values in the model,
but the Param page is not updated. On the Optimize page, the
values after the optimized values are placed into Column E. If any
5-14 • Running Cases
Aspen FCC 12.1 User Guide
upper or lower bound is reached, that value will be highlighted in
red. A typical optimization will take 3 to 5 minutes, but this could
vary depending on how difficult it is to reach a solution.
LP Vector Generation
Running LP Vector
Generation
In addition to letting you determine yields, temperatures, and
product properties, Aspen FCC can generate LP vectors.
Generating LP vectors is a two-step process. You must first specify
the independent and dependent variables, then run the LP vector
generation command. For information on setting up the variables
see Setting up LP Vector Calculations. on page 4-11.
1 On the AspenFCC toolbar, select LP Vectors; then click the
Run Case button.
-orSelect the AspenFCC| Run Cases | Generate Vectors menu
command to generate LP Vectors
The model will calculate all elements in the Jacobian (first order
derivative matrix) for the model equations, generate the desired
vectors, and place the results in the LP Vectors worksheet. The
command line window will appear for a short time while the
Jacobian is being evaluated and while the LP vectors are being
calculated, but you cannot issue any commands at this time.
Typical execution time is about 20 seconds, although it can be
more or less depending on the number of many vectors being
calculated.
LPVectorsWorksheet
Aspen FCC 12.1 User Guide
Running Cases • 5-15
5-16 • Running Cases
Aspen FCC 12.1 User Guide
CHAPTER 6
Advanced Topics
Parameter Case Analysis
This section presents useful tips, tricks, and techniques to verify
the quality of the Parameter case. The accuracy of Aspen FCC
model predictions is highly dependent upon the validity and
quality of the test run data used and the application of appropriate
settings in the FCC model data.
The focus will be on a number of input/output sheets employed to
set up and run a Parameter case including Options, Param,
Analysis, Feed Blends, and Cat Blend. The Options sheet
discussion is for setting up a parameter case. After the parameter
case has been run, the model calculation results can be used to
determine the quality of the data and the validity of the options
selected. The analysis discussion will be based on reviewing data
reported on the Analysis, Feed Blends, and Cat Blend sheets. The
parameter case results are useful to investigate the quality of the
test run data from the perspective of overall plant fundamental
heat, material, and chemical balances.
The various topics discussed include setting up options, input data
tips, and review of key analysis sheets.
Parameter Options on Review the Options worksheet. on page 3-11. A few of the key
Options Worksheet
options are reviewed here with particular impact on parameter
cases. It is important that some specific options are used or not
used for the Parameter case.
As mentioned in that section, after you change the options, you
must click the Update Spec Colors button on the toolbar. This will
change the cell color to blue for all the mandatory data entries.
Feed Rate Basis
Aspen FCC 12.1 User Guide
The Feed Rate Basis option allows specification of feed rates in
either mass or volume flow units. The units of measure are
determined elsewhere in a script file. However, the flow basis must
be selected for a parameter case and not changed for other cases. If
Advanced Topics • 6-1
the flow basis is changed after running a Parameter case and then a
Simulation case is run, all of the feed flow rates must very
carefully be changed throughout the interface. Otherwise, the
model could easily encounter an infeasibility with an apparently
either huge or very small feed flow rate.
Feed Gravity Basis
The Feed Gravity option allows various methods of calculating or
specifying the feed gravity. For Parameter cases, you must select
either the Input API or the Input SG option. The other options are
used only for generating LP vectors. The gravity basis should not
be changed after running a Parameter case or there is the risk that
the feed flow rate and characterization calculations will become
infeasible. For example, an APIof 0.88 will generate a feed
composition that looks like FCCcycle oil, whereas a SG of
0.88may generate a very typical VGO characterization.
Product Gravity Basis
The Product Gravity option allows the selection of either API or
SG to be entered for Parameter case data. This has no impact on
case modes other than Parameter. However, if you change this
option, take great care to enter the Parameter case gravities on the
correct basis.
Light-Ends Product Rate
Basis
The light-ends flow rate may be entered on either mass or volume
flow rate basis. This option is similar to the product gravity option
in that it only affects the Parameter case.
Heavy Product Rate
Basis
The heavy product flow rates may be entered on either mass or
volume flow rate basis. This option is similar to the product gravity
option in that it only affects the Parameter case.
Fractionation Control
This option allows the selection of how the fractionation is
controlled to best match the actual plant operations. It is common
for heavy naphtha and HCO to be on draw rate targets, but these
draw rates may be specified in either volume or mass rate units.
When selecting the All Use TBP90 option, you should be very
careful when running simulation cases so that the adjacent 90%
targets don’t get so close that they become infeasible. All the other
options here tend to be much more robust.
Fresh Feed Basic or
Total Nitrogen
This option provides flexibility in the feed nitrogen content to be
entered as either basic nitrogen or total nitrogen. Internally, Aspen
FCC is always driven by basic nitrogen. If the Total Nitrogen
option is selected, the model will determine the basic nitrogen by
applying a basic-to-total ratio of 1:3.
Regenerator Control
This regenerator control option has no impact on the parameter
case. All options selected require the same input data to
parameterize the regenerator kinetics. However, it makes sense to
select the option that is appropriate for running simulation cases.
Most often, it is best to try to mimic the advanced control scheme
6-2 • Advanced Topics
Aspen FCC 12.1 User Guide
of the regenerator. If advanced control has not been implemented
on the unit, then the operation philosophy should be used to
determine the most appropriate regenerator option.
The first and most important choice to be made is to select either
complete or partial combustion mode. Typically, if the excess O2
in the flue gas is over 0.5% and the CO is close to zero, the unit is
most likely in complete combustion (sometimes called full burn
mode). Partial combustion is noted by very low O2 in the flue gas
(less than 0.5%) and a substantial amount of CO (over 1%). It is
common to have 5% or even greater CO in the flue gas in partial
combustion units.
Pressure Balance Control The pressure balance control is used to approximate the advanced
control system behavior. However, for Parameter cases it is best to
select the All Pressures Const option. This means that the
pressures must be entered for regenerator, reactor, and wet gas
flash (fractionator overhead accumulator) pressure. The model will
then calculate the delta P between the various control points. After
the Parameter case is run, the most appropriate option can be
selected confidently without fear of getting the delta P sign
incorrect.
The WG to RX DP Const option means that the regenerator
pressure is constant at whatever value is entered for the
regenerator. In addition, the wet gas suction pressure is also held
constant at the user-input value. The reactor pressure will be
determined from the back-pressure through the main fractionator
as determined from the parameter case calculations.
The WG-RX and RX-RGN DP Const option means that the wet gas
suction pressure and reactor/regen Delta P are held constant at the
user input values. The reactor pressure will be determined from the
back-pressure through the main fractionator as determined from
the parameter case calculations. The regenerator pressure is
calculated from the reactor pressure plus the reactor/regen Delta P
input value.
Param Sheet Input Key Operating Data
The key operating data entered on the Param worksheet is
described below.
Regenerator
Temperatures
The Regen Flue Gas Temp should always be at least a few
degrees higher than the Regen Bed Temp. If this is not the case,
then you take the risk of making the regenerator dilute phase
kinetics infeasible.
Carbon on Regen
Catalyst
The Carbon on Regen Cat should never be set to 0.0%. In fact, it
is rarely if ever less than 0.03% in real operating units and
typically runs at about 0.05% for most complete combustion units.
Aspen FCC 12.1 User Guide
Advanced Topics • 6-3
Partial combustion units operate from 0.05% and higher, often
running at or above 0.10%.
Flue Gas Composition
None of the flue gas compositions should ever be set to zero. If the
actual value is not known, then one should be estimated from
historical data, if available.
In complete combustion units, it is common for the CO to not be
reported or even analyzed. If it is reported, the results are often
inaccurate due to poor calibration. In this case, set the CO to
0.05%. In any case, the CO should never be set below 0.05% in a
Parameter case. Check with the laboratory to see if argon is
included as O2 in the analytical method being used; this is typical
of many GC methods. If this type of data is entered, the coke yield
will be under-estimated.
In partial combustion units, the O2 might not be reported or
reported as 0.0%. In this case, set the O2 to 0.05%. In any case, the
O2 should never be set below 0.05% in a Parameter case. If the
reported value for O2 is at or above 0.9%, check with the
laboratory to see if argon is included as O2 in the analytical
method being used; this is typical of many GC methods. If the O2
is very much above 0.3%, the analysis may be bad or poorly
calibrated for such a low concentration of O2 as is normal in a
partial burn unit.
Air Rate
The air rate to the regenerator is entered on a wet basis. The total
air rate should include all air sources such as aeration or lift air to
the catalyst transfer lines and regenerator standpipe.
Pressure Balance
In a Parameter case, the All Pressures Const option should be used
to specify the unit pressure balance. The Sign of Rg/Rx DP should
be set to either –1. or +1. to achieve the appropriate value for the
Rg/Rx DP value. The appropriate value is defined as whatever is
recorded by the advanced control system or DCS. It is typical for
this DP to be always recorded as a positive number.
Heat Removal
The steam flow rates are set to a very small number by default.
These should never be set to exactly 0.0 or the model equations
will become singular. Similarly, if there are not bed coils in the
operating unit, the number of bed coils and the surface area per bed
coil should be left at the default non-zero values.
Param Sheet Input - Feed Data
The feed data entered on the Param worksheet consists of the
following for each feed:
• Feed Type
• S Crackability
6-4 • Advanced Topics
Aspen FCC 12.1 User Guide
•
•
•
Refractive Index and Viscosity
Distillation Type
Feed Metals Option
Feed Type
Select the feed type that most closely matches the feed entering the
unit. VGO is the most common feed. In cases where high-pressure
hydrotreatment is involved, select the HTVGO feed type. Heavy
resid processors should select the RESID feed type. Other much
less common feed types processed include coker gasoils (LCKGO,
HCKGO, MXCKGO) and Syncrude (SYN). If the feed type
selection is still unclear, please contact AspenTech customer
support for additional advice.
S Crackability
This value indicates how easily the sulfur compounds are removed
from the feed. It correlates with the amount of thiophenic
compounds in the feed itself. A VGO feed type sulfur crackability
should be set to 0., whereas coker gasoil sulfur crackability should
be set to 1.0 where most of the remaining sulfur compounds are
thiophenic. A hydrotreated feed sulfur crackability depends on the
severity of hydrotreatment and should be set at about 0.5.
However, since hydrotreated feeds typically have very little sulfur
remaining in them, the value is normally much less important than
for VGO’s.
Refractive Index and
Viscosity
The refractive index has a significant impact on the feed
characterization aromatics content. If the lab data is available, then
it is recommended that it be entered. However, if lab data for the
specific feed sample being evaluated is not available, do not enter
in a value estimated from historical data. Even a small error in the
RI can mean a large swing in the aromatics content. In this case, it
is better to change the RI data option to Estimate, meaning that the
model will use a correlation to estimate the RI consistent with the
distillation and gravity of the feed sample.
The viscosity also contributes to the estimate aromatics content but
is much less important than the RI. If the viscosity data is not
available from the lab then it should be estimated by switching the
Visc Option to Estimate.
Distillation Type
In a Parameter case, only the following options should be chosen:
D2887, D1160, D86, or TBP. After the Parameter case has been
run, the other options can be used to report additional distillation
types, and VABP control mode can be used for LP vector
generation. These other options may be selected in subsequent
Parameter cases as long as the basic distillation input data has not
changed.
Feed Metals Option
Aspen FCC performs a metals balance calculation. In essence, the
mass rate of metals being deposited on the catalyst is forced to
Aspen FCC 12.1 User Guide
Advanced Topics • 6-5
match the mass rate of metals being removed from the unit. The
deposited metals enter the unit as part of the fresh feed and a very
small amount on the fresh makeup catalyst. The metals are then
removed from the unit along with catalyst fines losses and catalyst
intentionally withdrawn from the regenerator (called spent or
equilibrium catalyst).
The metals balance derived from plant must be reconciled. This is
because the data used to define the metals balance is the result of
averaged equilibrium catalyst metals content, average catalyst fines
metals content, and often, instantaneous feed metals content. The
actual unit acts as an integrator; absorbing a variety of metals
levels in the feed and varying feed rates all the while the fresh
catalyst make up rate being fairly constant. In addition, metals
analyses of FCC feeds are taken only infrequently and is not done
as part of usual plant data collection. In addition, the metals
analyses of the catalyst and feed are subject to significant errors
and in any case, they do not account for tramp metal from the
process units.
The Parameter case provides an opportunity to allocate the errors
in the metals balance reconciliation.
• The most straightforward way of doing this is to select one of
the feeds to allocate all the error to. For example, if only feed
number one has been entered in the Parameter case, select the
Calc Feed 1 Metals option. When the Parameter case is run,
the model will back-calculate the feed number one metals
content based on a perfect metals balance. This is an interesting
approach because it determines the average amount of feed
metals that have entered the unit over the long term.
Note: The feed metals calculated in this way would include
tramp metals.
•
•
6-6 • Advanced Topics
A second way to handle the metals balance is to assign the
metals balance error to parameters. This is accomplished using
the Enter Feed Metals option. In this case, the best available
metals data for the non-zero rate feeds are entered into the
Param sheet. The model will calculate the delta between the
average feed metals from the input data and the average feed
metals back-calculated from the metals balance. The delta may
be positive or negative and will be assigned to the parameter
values. In future simulation or optimization cases, the deltas
will be added to any entered feed metals input data.
A third way to handle the metals balance is to ignore it. If there
are no specific metals issues of interest at the particular process
unit, or if the parameter case in question will not be used to
analyze metals issues then this may be perfectly appropriate.
Aspen FCC 12.1 User Guide
To do this, select the Enter Feed Metals option and enter zero
for all the feeds with a non-zero flow rate. The model will
calculate the delta between the average feed metals from the
input data (zero) and the average feed metals back-calculated
from the metals balance. The delta in this case will exactly be
the average feed metals content given the entered fresh and
equilibrium catalyst metals content. In future simulation or
optimization cases, the deltas will be added to any entered feed
metals input data. Therefore, all feeds will automatically be
assigned the average feed metals content although the input
data is shown as zero.
Param Sheet Input Heavy Liquid Product
Streams
There are two areas where distillation data are entered:
• The reactor parameterization area .
• The simple fractionator parameterization area .
The distillation types selected should be one of D2887, D1160,
D86, or TBP for a Parameter case. After the Parameter case is run
once, then the type can be changed to one of the Dxxx & All
selections.
Param Sheet Input Catalyst Data
The average fresh catalyst properties are calculated in the Excel
sheet using a formula that blends the properties on a mass blend
basis. The average properties are reported in the Blend column.
Once the fresh catalysts have been selected from the combo-boxes
and the percentage makeup has been entered, the blend properties
are immediately available. The fresh blend properties should be
compared to the ECAT and fines catalyst analyses entered. The
MAT and surface area must be lower than the blend values. The
Iron and Sodium values must be higher than the blend values. If
the equilibrium catalyst data from the lab does not follow this
trend, the fresh catalyst types and Mix wt% should be checked. If
there is still disagreement, contact AspenTech customer support
for additional consulting.
Feed Blend Sheet
Review
There are many areas on the Feed Blends sheet that may be of
interest depending on the specific FCC unit. A few of the essential
items that are important to all FCC units are discussed briefly
below.
Lab Data versus
Estimations
Compare the model-estimated RI and viscosity with the lab data.
Large differences in these values might imply that the feed
properties are inconsistent. Review the feed gravity for significant
errors.
Aromatic Content
Compare aromatics estimations from the Total method and from
the contribution that each feed makes to the total aromatic pool. If
the correlation predicts either lower than 15% or higher than 25%
aromatics, review the feed type being processed and the feed
Aspen FCC 12.1 User Guide
Advanced Topics • 6-7
properties to ensure the result is rational. Also, consider using an
Estimated RI instead of a Lab RI data entry.
It is also worthwhile to review the full 19-lump composition data
reported for the blended total feed. For a Parameter case, the ring
balance can indicate inconsistent data. For example, the total
bottoms yield should not be too close to the total 3-ring
concentration in the blended feed. The 3-ring aromatics can only
convert to coke or remain un-cracked as bottom material. If the
bottoms yield target is too low, the parameter case may be
infeasible.
Cat Blend Sheet
Review
Reported on the Cat Blend sheet are the final yield factors for each
catalyst after the compositional shifts and the yield factors for the
blended catalyst.
Analysis Sheet
Review
The data available on the Analysis worksheet consists of the
following:
• Material Balance
• Heat Balance
• Feed Vaporization
• Reactor Dilute Phase Cracking
Material Balance
The material balance section reports the errors in the mass flow
rates. These errors are the results of reconciling the material
balance information derived from the input data. By default,
AspenFCC puts the mass balance error in the light naphtha stream.
If this error is greater than about 2-3% of the total feed mass rate,
the flow rate and gravity information should be reviewed.
The standard cut products section reports the volume percent of the
standard cut yields derived from the observed plant data. The
standard liquid cuts includes C5-430F, 430-650F, and 650F+
streams.
The sulfur balance section reports how the feed sulfur is distributed
among the products. The sulfur in H2S should be roughly half of
the feed sulfur.
The conversion section reports feed conversion on a standard 430F
cut point basis and on an observed naphtha flow rate basis.
Heat Balance
6-8 • Advanced Topics
The heat of cracking section reports the actual and theoretical heat
of cracking. If the difference between these two values is greater
than 40 or 50 BTU/lb. of feed, then the regenerator data should be
reviewed for consistency and perhaps compared to historical data.
For example, it is not unusual to have as much as a 10% error in
the air flowrate measurement. In addition, the flue gas analysis can
have a significant impact on the heat balance calculation as well.
Aspen FCC 12.1 User Guide
To determine if the flue gas analysis is in question, review the
hydrogen on coke report section. If the total coke average
hydrogen content is outside the range of 5-8%, there is a good
chance that the flue gas analysis is in error. However, there are a
very few units operating around 5% (unusually good) or over 8%
(unfortunately quite bad).
The coke distribution report section should be reviewed. The
stripper source coke should be roughly 15%; this is actually input
directly on the Param sheet. The kinetic coke should be anywhere
from 50% to 80%.
If the metals coke is greater than 15%, great care should be taken
to ensure this is reasonable. For example, the nickel equivalent
should be quite high and with little or no nickel passivation
additive. If this is not the case, then there is a real possibility that
the H2 yield is too high. A review of the light gases flow rate
and/or the composition might reveal an error.
Feed Vaporization
The riser feed mix conditions section reports the composition of
the total riser feed, the temperature of the catalyst plus feed oil
mixture at the bottom of the riser, and the calculated dew point. If
the dew point is close to or below the mixed temperature, then
some care should be taken to review the feed distillation, gravity,
and cat/oil ratio. If the conditions are judged legitimate, then the
non-vaporized feed coke option should be considered. This will
have a significant impact on the incremental coke make due to
incremental feed rate.
Reactor Dilute Phase
Cracking
The riser/reactor catalyst inventory section reports the amount of
catalyst held up in the catalyst dilute phase. If it is understood from
the unit designer that there is a significant catalyst holdup in the
reactor dilute phase, then the dilute phase volume and resulting
catalyst inventory should be adjusted to provide the appropriate
amount of post-riser cracking.
Model Tuning
Heat Balance Tuning
The heat balance for Aspen FCC can be tuned so that the
regenerator response to changes in feed rate or preheat temperature
match expected values. This tuning can be achieved by changing
key parameters in the stripper model and running a parameter case.
The stripper source coke is defined as the hydrocarbon entrained
with the catalyst in the stripper and then transferred to the
regenerator where it appears as coke and is burned. This stripper
coke is relatively high in hydrogen content, causing a much higher
heat of combustion than the feed and kinetic sources of coke.
Therefore, it is much more detrimental to the regenerator bed
Aspen FCC 12.1 User Guide
Advanced Topics • 6-9
temperature, resulting cat/oil ratio, and finally the conversion.
Also, the stripper source coke has roughly the same composition as
the reactor effluent (50% of the hydrocarbon is highly valued
gasoline).
Two key parameters can be used to tune the stripper model, the
performance slope, and the percent of total coke whose source is
the stripper. Typical values of performance slope are between 0.5
and 1. A typical value for the percentage of coke generated from
the stripper is 15%. You may enter new values for these in the
TUNING DATA section of the Param sheet.
The biggest handle for tuning the stripper is the performance slope.
If you want the regenerator temperature to have a larger increase
for an increase in feed rate, increase the performance slope. It is
recommended that this slope is not increased to more than 4 or 5.
For example, in the Aspen FCC demo problem the regenerator
temperature is 1300 °F in the base case. Upon a 10% increase in
the feed rate, the model predicts that the regenerator temperature
increases to 1311 °F, or an increase of 11 °F. If this increase in
temperature is too low, the model can be re-tuned by increasing the
performance slope of the stripper.
You should enter a new performance slope in the TUNING DATA
section on the Param sheet. The figure below shows that a value
of 2 has been entered. Then run a parameter case. Select
Parameter from the combo box on the Aspen FCC toolbar and
click the run button.
Change stripper performance slope to 2 and run a parameter case
After the parameter case has been run, determine the new
regenerator response by running another simulate case. On the
Simulate sheet, enter the new flow rate as shown below. In the
demo case, a 10% increase corresponds to a new feed rate of 33
MBBL/DAY. Enter this in the FEED DATA section as the
6-10 • Advanced Topics
Aspen FCC 12.1 User Guide
volume flow for feed 1 (the only feed that has a non-zero flow rate
for the demo case).
Increase feed rate by 10% and run a simulate case
After the new flow rate has been entered, select Simulate from the
combo-box of the Aspen FCC toolbar and click the run button.
After the model has solved, the results for the regenerator
temperature appear in the section KEY OPERATING DATA on
the Simulate sheet. In this case, a 10% increase in feed rate causes
the regenerator temperature to increase from 1300 °F to 1317 °F.
View results after simulation case is run to observe regenerator
response
Aspen FCC 12.1 User Guide
Advanced Topics • 6-11
If the increase in regenerator temperature is still too small, you
may again increase the performance slope of the stripper and run
another parameter case. After a parameter case has been run, you
may run another simulate case with a 10% increase in feed rate to
observe the regenerator temperature response. In this case, by
doubling the performance slope again to 4, the regenerator
temperature increases to 1321.6 °F for a 10% increase in feed rate.
It is recommended that the performance slope not be changed to a
value greater than 4 or 5. If the regenerator response is still not
what is expected after the performance slope has been changed,
you may change the percent of total coke that comes from the
stripper. As with the performance slope, this data can be entered on
the Param sheet in the TUNING DATA section. A maximum
value of 25% to 30% should be used. In the example shown below,
a value of 30 has been entered. After entering a new value, run a
parameter case.
Increase the percent of total coke due to stripper from 15 to 30
percent and run a parameter case
After the Parameter case has been run, again run a Simulate case
with a 10% increase in feed rate. In this case, by increasing the
percent of coke from the stripper to 30% and keeping the
performance slope at 4, the model predicts the regenerator
temperature to be 1324.8 °F for a 10% increase in feed. Note that if
the increase in regenerator temperature is still not high enough, the
performance slope and percent of total coke due to stripper should
not be increased beyond 5 and 30 respectively. You should contact
Aspen Technology if the desired regenerator response cannot be
achieved with these constraints.
Over-cracking
6-12 • Advanced Topics
The Aspen FCC model allows you to tune the cracking kinetics so
that the naphtha over-cracking peak occurs at the right
temperature. Before tuning the over-cracking peak, you should first
determine where the model predicts over-cracking to occur. This
Aspen FCC 12.1 User Guide
can be done using the case study feature. Set up a Case Study that
varies the riser temperature and reports the naphtha yield.
Begin the case study by selecting the menu command AspenFCC |
Setup Cases | Case Study. This will open the Setup Case Study
dialog box, which contains two pick lists, one for the independent
variables and one for the dependent variables. From the
independent variable list, select the variable that is used to control
the riser temperature: reactor plenum temperature, riser overhead
temperature, regen cat slide valve percent open, or spent cat slide
valve percent open. Only the variable that is used for controlling
the riser temperature will show up in the pick list. From the
dependent variable list, select the variable for debutanizer bottoms
yield on a fresh feed basis. You may also select any other variables
from the dependent variable list that are of interest. After the
appropriate variables have been selected, click OK.
Select the reactor plenum temperature as the independent variable
and select the debutanizer bottoms on a wt% fresh feed basis as the
dependent variable
Aspen FCC 12.1 User Guide
Advanced Topics • 6-13
Once the Case Study is set up, you should enter the different
values of the independent variables that will be used in the case
study. In this example, the reactor plenum temperature is the
control target. The base model is parameterized to a value of 990
°F. Five cases will be run starting with 980 °F and ending with
1020 °F. Before the data is entered, delete any data from previous
case studies that is in columns that will be used. Then enter the
values for the reactor plenum temperature in the appropriate cells
as shown below. Also, select (in row 8) the desired number of
creep steps for each case. If you don't know how many creep steps
to use, try the typically safe value of 10.
Enter data for the reactor plenum temperature for each case in the
case study
Once the case study is set up and the data has been entered for the
independent variables, the model is ready to run. Select the Case
Study option from the Aspen FCC toolbar and click the run button.
Immediately, a dialog box appears, asking for the first and last
cases to be run.
Enter first and last cases to run
6-14 • Advanced Topics
Aspen FCC 12.1 User Guide
In this example, 1 is the first case and 5 is the last case. The
Calculate LP Vectors option is selected by default. Clear this
option if you do NOT want to have LP Vectors calculated. If you
do not clear this option, LP vectors will be run for each case and
reported in rows 1000 and higher on the Case Study worksheet.
The LP vectors that are run will be based on the settings on the LP
Vectors worksheet. When you have entered the information, click
the OK button.
Case study results
After the case study is run, you can detect the over-cracking peak
by manually inspecting the data or using the built-in Excel
capability of graphing the data. In this case, a maximum value of
debutanizer bottoms occurs between 990 °F and 1000 °F. At this
point you can start tuning the over-cracking peak.
Over-cracking peak for an Ea/R value of 60,000
Aspen FCC 12.1 User Guide
Advanced Topics • 6-15
The first step to tuning the over-cracking peak is to select the
option Reset Ea/R from the naphtha over-cracking combo-box on
the Param worksheet. This combo-box appears toward the bottom
of the sheet, in the Tuning Data section. The Reset Ea/R option
fixes the reference reaction rate so that you can move the
activation energy by large amounts without causing the reaction
rate to get so large that the model can no longer solve. After
selecting this option, enter a new value for Ea/R and run a
parameter case. To shift the over-cracking peak to a higher
temperature, decrease Ea/R. To shift the over-cracking peak to a
lower temperature, increase Ea/R.
Select the Reset Ea/R option for naphtha over-cracking
After the parameter case with the new Ea/R value has been run,
run another case study to see how the over-cracking peak has
shifted. In this example, the Ea/R was decreased from 60,000 to
50,000. An increased temperature for over-cracking should be the
result. Since the case study is already set up, you need only to
select Case Study from the Aspen FCC toolbar again and click the
run button. From the first dialog box click OK, then click either
Yes or No in the LP vector dialog box.
After the case study is run, you can look at the results in the
independent variables. If the data has been graphed, the graph will
be automatically updated with the new data, if the same case study
range was used. The figure below shows a graph of the updated
over-cracking peak. In this case over-cracking occurs between
6-16 • Advanced Topics
Aspen FCC 12.1 User Guide
1000 °F and 1010 °F. This result agrees with the expectation that
the over-cracking peak should increase with decreased Ea/R.
Over-cracking peak for an Ea/R value of 50,000
You can continue to run various parameter cases at different Ea/R
values followed by case studies until the desired over-cracking
peak is achieved. At that point, you should set the naphtha overcracking option back to default and run another parameter case.
This will set all variable specifications back to the default values.
Catalyst Makeup versus
MAT
Makeup Rate versus MAT. Frac = makeup rate/inventory
If the value of the fractional make-up rate is small (less than 5%),
you will typically not need to tune the response of make-up versus
MAT activity. However, if Frac is too large (5 to 10%), the model
can blow up when trying to increase activity. In that case, you can
increase the value of the variable
CATP.BLK.MDADJ_METALS_DEACT_BASE to decrease the
sensitivity of make-up rate to MAT activity.
Aspen FCC 12.1 User Guide
Advanced Topics • 6-17
Tuning parameter: Decrease the cat inventory to get into the region
of 0.5%. Cat inventory should be viewed as the active catalyst
inventory in the unit, not the total amount of inventory as viewed
by the refiner.
If regen and rx cat losses are set too high, then the model can get
into trouble when trying to achieve the activity target. When
decreasing the MAT target, the makeup rate will decrease.
However, the minimum makeup rate is equal to the total fines
losses and therefore, there is a minimum feasible MAT target.
The equation to determine the fractional makeup rate is as follows:
X_Frac_MUP= X_Cat_deact_K * (X_Equil_cat_ZACT +
X_HTdeact_Term * X_Cat_deact_P4) /
(X_Cat_deact_Param * X_Fresh_Cat_ZACT X_Equil_cat_ZACT - X_HTdeact_Term *
X_Cat_deact_P4)
The term X_Htdeact_Term * X_Cat_deact_P4 is small
compared to the other terms in the numerator and the denominator
so the fractional makeup rate can be approximated with the
following equation:
X_Frac_MUP= X_Cat_deact_K * X_Equil_cat_ZACT /
(X_Cat_deact_Param * X_Fresh_Cat_ZACT X_Equil_Cat_ZACT)
Or directly calculating the makeup rate using the names of the
variables in the model:
RREXP.BLK.MAT_FRESH_CAT_MUP =
RREXP.BLK.MAT_TOTAL_UNIT_INV*
RREXP.BLK.MAT_CAT_DEACT_K*
RREXP.BLK.MAT_EQUIL_CAT_ZACT/
(RREXP.BLK.MAT_CAT_DEACT_PARAM*
RREXP.BLK.MAT_FRESH_CAT_ZACTRREXP.BLK.MAT_EQUIL_CAT_ZACT)
In this equation, the equilibrium and fresh catalyst ZACT values
are fixed based on the MAT activity values. The total catalyst
inventory is constant and the fresh makeup rate is fixed for a
Parameter case. The catalyst deactivation parameter is calculated
in a Parameter case to match the input catalyst makeup rate. The
only other variable that can be changed to achieve the correct
response is the catalyst deactivation K. The variable
CATP.BLK.MDADJ_METALS_DEACT_BASE will change
the calculated value for the catalyst deactivation K.
Adding New
Catalysts
6-18 • Advanced Topics
Aspen FCC comes preconfigured with several catalyst types from
which to choose. The catalyst type will affect yields, selectivities,
and product qualities. This is accomplished in Aspen FCC with
catalyst factors that are used as multipliers or additives to various
parameters in the model. Analyses to determine the factors are
performed by Refining Process Services.
Aspen FCC 12.1 User Guide
In addition to being able to choose from the preconfigured catalyst
types, you can choose to have the catalysts that you use analyzed.
These new factors can then be easily added to the Excel GUI for
Aspen FCC.
Work Process
Unhiding the CST
Factors Worksheet
All catalyst factors are stored in the hidden worksheet CST
Factors. In order to add a new catalyst, you must first unhide this
worksheet. Adding new catalysts is a three-step process.
1 Unhide the CST Factors Worksheet
2 Add the Catalyst Data
3 Re-hide the CST Factors Worksheet
To unhide the CST Factors Worksheet:
1 On the menu, click Format | Sheet | Unhide.
This opens the Unhide dialog box that contains all the hidden
worksheets.
2
Adding Catalyst Data
Aspen FCC 12.1 User Guide
Select the worksheet CST Factors; then click the OK button.
To Enter Catalyst Information:
1 On the CST Factors worksheet, go to the first blank column
on the page. Enter the catalyst name in Row 1.
2 Enter the catalyst ID in Row 2. The catalyst ID should be a
unique integer that identifies the catalyst. Because values
between 1 and 1000 are reserved for the default catalysts that
come with the model, you should assign a value of 1001 or
greater to any new catalysts.
Advanced Topics • 6-19
3
In Row 3, you can enter the catalyst vendor.
CST Factors Worksheet
4
Enter the catalyst factors for the new catalyst in Rows 4
through 73.
Once these values have been entered, the new catalyst is ready to
use.
Re-hiding the CST
Factors Worksheet
Before connecting to the model, you should first hide the
worksheet again and save the workbook.
To re-hide the CST Factors Worksheet:
• On the menu, click Format | Sheet | Hide.
This hides the sheet you are currently have open, so make sure that
you are still in the CST Factors worksheet.
After the FCC model is loaded, the new catalyst should appear as
the last item in the pick list.
If you are already connected, you can also update the combo-boxes
for catalyst type.
To update the combo boxes for Catalyst Type:
• Select Aspen FCC | Development Tools | Update Catalyst
Combo Boxes.
Note: Do not use this option with Excel 97.
Feed Characterization
Aspen FCC allows you to select a feed type and input feed quality
information that will adjust the kinetic lumps associated with that
feed. This characterization uses two types of data: a feed
fingerprint and standard inspection properties. The fingerprint can
be calculated from detailed feed and product analyses including
6-20 • Advanced Topics
Aspen FCC 12.1 User Guide
GC/MS, 13C NMR, distillation, S content, and HPLC. These
fingerprints are used to define the basic character of the feed type
or class being processed and can be adjusted somewhat to match
more routinely available bulk properties like distillation and
gravity. Fingerprints for many feed types have been provided with
the Aspen FCC model so that you need only to select the feed type
and input bulk properties. Feed composition changes are taken into
account using the feed bulk inspection properties described in Feed
Properties.
Feed Properties
Typical Feed Properties to Adjust Fingerprints
Test
Method
Distillation
API Grav @60
Sulfur, wt%
Viscosity @ 210 °F, cst
Total Nitrogen, wt%
Conradson carbon, wt%
Metals (Cu,Fe,Na,Ni,V), ppm/wt
Refractive Index
D2887, D86, or D1160
D287
D4294
D445
D4629
D4530
D1747
Distillations are used to reshape the distribution of mass in the
fingerprint and determine the mass of material in the boiling ranges
for the gasoline, light, heavy and resid lumps. The gravity, sulfur,
viscosity, and refractive index are used to determine the
aromaticity of the feed. You have the option to estimate the RI or
viscosity if the data is not available or if the error of measurement
is too large. Conradson carbon is used as a part of the coke
calculation in the risers, reactor, and regenerator. Nitrogen and the
metals are used to calculate catalyst activities.
The adjustment method used assumes that provided a fingerprint of
a coker gasoil for a reference, the inspection properties, and
distillation for another gas oil will shift the aromatics in the correct
direction. This same principle applies to any other type of feed as
long as there is a representative fingerprint available. If no suitable
fingerprint is available, contact Aspen Technology about
generating a fingerprint and adding it to the interface.
Selecting Feeds and
Entering Property
Information
Aspen FCC 12.1 User Guide
You should first select the feed types for each feed that is being
used. This can be done on the parameter page or the simulate page.
The figure below shows the feed selection combo box for the first
feed. There is one for each of the ten possible feed slots and you
should specify the appropriate feed type for any feed that has a
non-zero flowrate.
Advanced Topics • 6-21
Selecting a feed type for Feed 1 using the combo box.
Once the feed type is selected for each feed, you should select the
RI option, Viscosity option, and distillation option for each feed
being used.
You should select to either enter a Lab measured RI value or to
have the value estimated from other data from the RI combo box.
Typically, unless the RI data is of high quality, it is recommended
that you select the Estimate option. If you select the lab measured
RI option and poor quality data is entered, the model may not
solve, since the Ca value is highly correlated with the RI value.
Selecting the desired RI option for Feed 1.
From the viscosity option combo box you should select to either
enter a lab-measured viscosity in cSt or SUS or have the viscosity
estimated from other properties. Unless the lab data is high quality,
it is recommended that you select to have the viscosity estimated.
However, since Ca is only weakly correlated with viscosity, errors
in lab measured values should not cause robustness issues.
Selecting the appropriate viscosity option for Feed 1.
Finally, you should select the distillation type from the distillation
combo box for each feed. You may select from D2887, D1160,
D86, and TBP. For each of these options, you may also select &all.
By selecting the &all option, the model is instructed to calculate all
distillation types for the feed. Aspen FCC uses the API correlations
to calculate the distillation types. However, since the API
6-22 • Advanced Topics
Aspen FCC 12.1 User Guide
equations are highly non-linear, selecting the &all option may
make the model difficult to solve. Therefore, it is recommended
that you never select the &all option when first entering data. Once
the model has been solved, you may change the distillation option
to include &all since this option should be more robust at that
point. The distillation combo-boxes include one last option, VABP
D1160. The VABP option should only be selected for generating
LP vectors. After the option is selected, run a Simulate case,
followed by an LP vector run. Once the LP vectors have been run,
set the distillation option back to what was selected previously and
run another simulate case. The reason for running the simulate
cases are because the specifications are not passed from the GUI to
the engine until the model has been run.
Selecting the desired distillation option for Feed 1.
After the desired options have been selected, you should enter all
of the necessary bulk properties in the appropriate cells. You
should first click the Update Spec Color button on the Aspen FCC
toolbar so that the appropriate input cells are shaded blue. See
Updating Spec Colors. on page 3-13. You should enter data into
any cell that is shaded blue for each feed that has a flowrate.
The Aspen FCC Engine
The Aspen FCC engine is Aspen Plus 12.1. You do not need to be
an Aspen Plus expert to use Aspen FCC. This section covers the
most important concepts in using the engine.
The first time the engine is used during an Aspen FCC session is
when the user interface connects to the server. This brings up a
Command Line window in which you will see the invoke
plant.ebs command, which sets the correct units of measure and
connects to the desired delumper model. The Command Line
window disappears when the kernel finishes building the model.
The engine is also used whenever you request a solution from the
user interface. Any changes you have made to data values or model
Aspen FCC 12.1 User Guide
Advanced Topics • 6-23
specifications (via combo boxes) are passed through DCOM from
the client to the server. The command prompt window appears and
you will see a stream of kernel commands going to the engine.
These commands tell the engine what mode of solution is required
and what solver settings should be used. There are different
sequences of commands for different types of solutions (parameter,
simulation, optimization, case study, LP vector generation, etc.).
You can look at the default command sequences on the EB Script
sheet on the user interface. The default command sequences are all
you need for running the model in any of the pre-configured
solution modes, but advanced users can modify them.
During a solve, you will see three buttons on the bottom of the
Command Line window:
• Abort
• Finish
• No Creep
You can use these buttons to interrupt the solver. The Abort button
causes the solver to quit at the next opportunity. See The
Command Line Window on page 3-1 for more information about
the purpose of these buttons and when to use them.
The engine is also used whenever case data is stored or retrieved.
The user interface typically contains only the results of the most
recent run of each solution type. The Save Case Data command let
you save the results of any number of previous runs to review or
use later. This user interface option is implemented using the
kernel commands read varfile from and write varfile to. You can
see these commands in the Command Line window while it is
active. You can open the Command Line window using the menu
command AspenFCC | Tools | Display Command Line to review
the previous commands.
6-24 • Advanced Topics
Aspen FCC 12.1 User Guide
CHAPTER 7
EO Modeling Background and
Examples
Equation-Oriented Modeling
Aspen FCC is based on an equation-oriented (EO) formulation, so
you need to understand some EO concepts in order to use it
effectively. The EO approach is also known as open-form
modeling and can be contrasted with the closed-form or sequentialmodular (SM) technique. The equations in an EO model are solved
simultaneously using an external solver, which iteratively
manipulates the values of the model variables until all the
equations are satisfied within a convergence tolerance. The solver
will work for any well-posed set of variable specifications. A
variable’s specification labels it as known (fixed) or unknown
(calculated) for each solution mode.
In contrast, an SM model is solved procedurally, one equation at a
time, and the solution procedure depends on a given specification
set. For different groupings of known and unknown variables, the
solution procedure will be different, since the equations will be
solved in a different order.
Pressure Drop Model
Example
A simple example illustrates some important EO concepts.
Consider this two-equation model where the pressure drop is
correlated with the square of the mass flow of a fluid:
Pressure drop correlation:
Define pressure drop:
DELTAP = PRES_PARAM * MASS_FLOW^2
DELTAP = PRES_IN – PRES_OUT
In an EO formulation, we rearrange these equations into residual
format. The value of the residual indicates how close that equation
is to being solved. At the solution, the value of every residual will
be zero, or at least close enough to zero to satisfy our numerical
convergence tolerance.
f(1) = DELTAP - PRES_PARAM * MASS_FLOW^2
Aspen FCC 12.1 User Guide
(= 0 at solution)
EO Modeling Background and Examples • 7-1
f(2) = PRES_IN - PRES_OUT - DELTAP
(= 0 at solution)
Note that f is the name of the vector of residuals and it has length
equal to the number of equations. The solver prefers to work with
vectors and equation index numbers, while we find it easier to use
equation names. The model defines names for each residual that
can be used in reports and solver debugging output. In this case,
we choose the names:
f(1) = ESTIMATE_DELTAP
f(2) = DELTAP_DEFINITION
Similarly, the five variables in this model can also be addressed as
elements of a vector x having length 5:
x(1)
x(2)
x(3)
x(4)
x(5)
Model Specifications and
Degrees-of-Freedom
=
=
=
=
=
DELTAP
PRES_IN
PRES_OUT
PRES_PARAM
MASS_FLOW
Once we tell the solver which variables are known (fixed) for a
given solution mode, it will manipulate the values of the unknown
(free) variables to drive the residuals to zero. For any system of
independent equations, the degrees-of-freedom (DOF) is equal to
the number of variables minus the number of equations minus the
number of fixed variables:
DOF = #variables - #equations - #fixed variables
The number of degrees-of-freedom of a system classifies it into
one of three categories:
Under-specified
Square
Over-specified
DOF > 0
DOF = 0
DOF < 0
The optimization mode of Aspen FCC is under-specified, while the
other modes (simulation, parameter, case study, LP vector) are
square. Over-specified problems are not allowed in Aspen FCC.
The pressure drop example has 5 variables and 2 equations, so we
must fix 3 variables to create a square system. Furthermore, we
cannot fix any arbitrary set of 3 variables. If all variables within
one equation are explicitly or implicitly fixed, the problem is not
well posed, as the solver can no longer manipulate any variable to
reduce that equation’s residual. Such an incorrect set of
specifications will cause a structural singularity in the solver.
However, Aspen FCC is designed so that if you use the standard
specification options provided in the user interface you will not
create a structurally singular system.
Here are some specification attempts for the pressure drop
example:
Fix DELTAP, PRES_OUT:
7-2 • EO Modeling Background and Examples
Under-specified; only acceptable for an optimization case with
Aspen FCC 12.1 User Guide
Fix DELTAP, PRES_OUT,
PRES_IN, MASS_FLOW:
Fix DELTAP, PRES_OUT,
PRES_IN:
Fix PRES_IN,
PRES_PARAM,
MASS_FLOW:
Modes and Multi-Mode
Specifications
proper selection of independent variables.
Over-specified!
f(1) = DELTAP – PRES_PARAM * MASS_FLOW^2
(fix)
(free)
(free)
f(2) = PRES_IN – PRES_OUT – DELTAP
(fix)
(fix)
(fix)
Square, but not well posed (structurally singular). All
variables in residual 2 are fixed! If you compare this to the
over-specified example, you can see that over-specification is
not allowed since it always leads to a structurally singular
system.
f(1) = DELTAP – PRES_PARAM * MASS_FLOW^2
(free)
(fix)
(fix)
f(2) = PRES_IN – PRES_OUT – DELTAP
(fix)
(free)
(free)
Square and well posed. A valid specification set. Note that
there are other valid specification sets, such as PRES_IN,
PRES_OUT, and MASS_FLOW.
In different situations, we may want to use different sets of fixed
and free variable specifications. Each set of variable specifications
is a solution mode. One of the strengths of the EO approach is that
the same model formulation and solver are used for all the modes.
Although there are many possible modes, Aspen FCC is
configured for three basic modes. The Simulation, Param and
Optimize sheets in Aspen FCC correspond to those three modes.
Case study and LP vector generation are also simulation modes.
Case study is simply a series of simulations with the same
specifications, but different values for key fixed variables. LP
vector generation is a simulation run followed by a sensitivity
analysis. The independent and dependent variables you choose for
vector generation must correspond to fixed and free variables in
the simulation mode. The Aspen FCC user interface examines the
current model specifications and lets you choose only proper
independent and dependent variables.
In order to label how each variable behaves in the various modes,
multi-mode specifications are assigned. A variable that is fixed in
every mode is called a CONST, while variables that are free in
every mode are called CALC. For example, in Aspen FCC the
reactor vessel diameter is usually a CONST because its value is
not calculated in any mode, while the weight percent hydrogen on
coke is usually a CALC because the model calculates its value
from other information.
Aspen FCC 12.1 User Guide
EO Modeling Background and Examples • 7-3
Measurements and
Parameters
While many variables have CONST or CALC specifications,
there are other variables whose behavior changes between modes.
A MEAS variable is fixed in the parameter-fitting (tuning) mode,
but free in the simulation and optimization (prediction) modes.
Conversely, a PARAM variable is free in the parameter-fitting
mode and fixed in the simulation and optimization modes. Usually
a MEAS corresponds to a plant measurement, while a PARAM is
a model tuning parameter or a bias to a measurement. Since the
MEAS and PARAM variables always have opposite specifications
in every mode, there are always the same numbers of MEAS and
PARAM variables so that every mode is properly specified.
Another rule of thumb is that it is possible to swap the
specifications on a pair of related CALC and CONST variables to
be MEAS and PARAM, since the number of DOF stays the same
in every mode.
The concepts of simulation and parameter-fitting mode and
CONST/CALC/MEAS/PARAM variables can be illustrated with
the pressure drop example.
Assume the equipment across which the pressure drop is measured
has an inlet pressure gauge, a DP cell, and a mass flowmeter. We
can specify the DP measurement (variable DELTAP) to be type
MEAS and the pressure drop parameter (PRES_PARAM) to be
type PARAM. We can define inlet pressure (PRES_IN) and mass
flowrate (MASS_FLOW) as CONST variables. The outlet
pressure (PRES_OUT) is always calculated from the other
variables, so it is type CALC.
f(1) = DELTAP - PRES_PARAM * MASS_FLOW^2
(MEAS)
(PARAM)
(CONST)
f(2) = PRES_IN - PRES_OUT – DELTAP
(CONST)
(CALC)
(MEAS)
This is a valid multi-mode specification, because in the simulation
mode MASS_FLOW, PRES_IN and PRES_PARAM are fixed and
PRES_OUT and DELTAP can be calculated from those values. In
the parameter-fitting mode, DELTAP, MASS_FLOW and
PRES_IN are fixed, and PRES_PARAM and PRES_OUT can be
computed.
Changing Specifications
with Combo Boxes
What if the plant we are modeling has both a DP cell and an outlet
pressure gauge? We have a choice as to which to use. From a
mathematical standpoint, it is just as valid to declare PRES_OUT a
MEAS and DELTAP a CALC as the other way around. Thus we
have two possible variable specifications affecting both our
simulation and parameter-fitting modes.
In Aspen FCC this type of spec swap is made using a combo box.
A combo box on the spreadsheet presents alternate specification
7-4 • EO Modeling Background and Examples
Aspen FCC 12.1 User Guide
sets that are equally mathematically valid. One of the sets may be
more appropriate for a given unit based on its configuration,
control strategy, instrumentation, type of lab test, mass or volume
basis for flowmeters, or a variety of other reasons. In our pressure
drop example, on the Param sheet we might see a combo box with
the following options:
• Use outlet pressure measurement
• Use pressure drop measurement
These choices correspond to the following specifications:
Use outlet pressure
measurement
Use pressure drop
measurement
DELTAP spec
CALC
MEAS
PRES_OUT spec
MEAS
CALC
Aspen FCC comes preconfigured with many combo boxes which
cover all the options needed to model most FCC units. However,
there may be some unusual configurations that require an
additional option for a combo box or some additional combo
boxes. Aspen FCC has the capability to modify, extend, or add
combo boxes by making changes to the Combo Table sheet.
For each combo box, the Combo Table sheet has an entry similar
to our example above. Each option on the combo box is a column
and each variable that is affected by that combo box is a row.
Once the tables are modified, macros can be run to update the
combo boxes. If this is necessary for your model, ask your Aspen
FCC support contact for detailed instructions. However, even if
you don’t need to modify a table, it can be helpful to look at the
tables for a better understanding of what some of the options mean
in terms of model specifications.
Optimization
Optimization is a prediction mode, so it is similar to Simulation.
The main difference is that there are positive DOFs (Degrees of
Freedom) in optimization mode, and the solver uses those DOFs to
maximize or minimize an objective function within limits on
certain variables.
To create optimization DOFs, change the specifications of some
CONST variables to OPTIM. OPTIM variables are fixed in
simulation and parameter-fitting modes and free in optimization
mode and are also known as independents. The other free variables
(MEAS and CALC) are known as dependents.
The solver requires that the number of OPTIM variables be equal
to the number of DOF, but that requirement is easy to satisfy by
starting with a well-posed square set of multi-mode specifications
and changing only CONST variables to OPTIM.
Aspen FCC 12.1 User Guide
EO Modeling Background and Examples • 7-5
To set up an optimization, you must do three things:
• Define an objective function.
• Specify the DOFs (independents).
• Specify bounds (limits) on the values of key independent and
dependent variables.
The objective function is often a profit function, with revenue
terms based on product or export utility flowrates and prices, and
cost terms based on feed or import utility flowrates and prices. For
more information on objective functions, see Setting up
Optimizations. on page 4-4.
You specify the DOF by selecting independent (OPTIM) variables
from a pick list. Aspen FCC presents only CONST variables in
this pick list in order to ensure that whatever set you choose will
lead to a well-posed problem. You can put bounds on any of the
independents, plus whichever dependents you select from another
pick list that includes CALC and MEAS variables that you may
wish to limit during the optimization run.
DMO Solver Background
When you click the solve button, Aspen FCC submits the
mathematical formulation of the problem to the DMO solver via
the kernel.
If the solution is successful, the kernel Command Line window
will close, the results of the solution will be returned to the Excel
GUI, and the status indicators will change to Ready and
Converged.
If the solver fails, the status indicators will show Ready and Not
Converged. In this case, you must perform some troubleshooting to
determine the cause of the failure. This section discusses the basics
of the solver technology and error messages issued by the solver
when certain types of errors occur.
Successive Quadratic
Programming (SQP)
The DMO solver is a specific implementation of the general class
of nonlinear optimization algorithms known as Successive
Quadratic Programming (SQP), which perform the optimization by
solving a sequence of quadratic programming subproblems. The
general optimization problem that DMO solves can be expressed
as follows:
Minimize f(x)
Subject to c(x) = 0
xmin ≤ x ≤ xmax
7-6 • EO Modeling Background and Examples
Aspen FCC 12.1 User Guide
Where:
Expression
n
Represents
x∈R
f(x) ∈ R1
Vector of unknown variables
Objective function
c(x) ∈ Rm
xmin ∈ Rn
Vector of constraint equations
Vector of lower bounds on x
xmax ∈ Rn
Vector of upper bounds on x
A simplified description of the DMO algorithm is outlined as
follows:
1 Given an initial estimate of the solution vector, x0.
2 Set iteration counter, k = 0.
3 Evaluate derivative of the objective function, gradient, and the
derivative of the constraints, Jacobian.
4 Initialize or update an approximation of the second derivative
matrix, or Hessian, of the Lagrange function. The Lagrange
function, f(x) + ∑ λici, accounts for constraints through
weighting factors λi, often called Lagrange multipliers or
shadow prices.
5 Solve a quadratic programming subproblem to determine a
search direction, dk. In the quadratic programming subproblem,
the objective function is replaced by a quadratic
approximation, constraints are linearized, and bounds are
included.
6 Check for convergence or failure. If the optimization
convergence criteria are satisfied, or if the maximum number
of allowed iterations, MAXITER, is reached, then end.
Convergence is achieved when:
• Objective function gradient ≤ OBJCVG
• Scaled or unscaled constraint residuals ≤ RESCVG
7 Perform a one-dimensional search to determine a search step
αk so that xk+αkdk is a better approximation of the solution as
measured by a line search or merit function. The reduction of
merit function requirement is sometimes relaxed to achieve a
full correction step.
8 Update iteration counter, k = k + 1, and loop back to step 3.
Changing DMO Parameters
Parameters for the solver can be changed with script commands.
Enter commands at the kernel command prompt or on the EB
scripts sheet in the Excel GUI.
Aspen FCC 12.1 User Guide
EO Modeling Background and Examples • 7-7
The script language for a parameter change is:
SOLVER SETTINGS parameter = value
The parameters are discussed in the following section. As an
example, the following commands:
SOLVER SETTINGS MAXITER = 10
SOLVER SETTINGS RESCVG = 1.0D-5
change the maximum number of iterations to 10 and the residual
convergence tolerance to 1.0D–5. This input would apply for all
modes.
Basic DMO Parameters
Here are the DMO parameters most commonly used with Aspen
FCC:
Variable
Description
Default
MAXITER
Maximum number of SQP iterations allowed
MINITER
Minimum number of SQP iterations allowed
CREEPFLAG Creep control flag. This mode makes the
optimizer moves more conservative. It is
very helpful when the problem diverges.
CREEPITER Number of creep iterations
CREEPSIZE Creep mode step size. This is the fraction of
the full step to be taken when in creep mode
RESCVG
Residual convergence tolerance
OBJCVG
Objective function convergence tolerance
50
0
No (0)
10
0.1
1.0D-6
1.0D-6
DMO Command Window Output and
Log Files
During each solution, the following iteration log is sent to the
command window:
Residual
Objective
Objective
Overall
Model
Convergence Convergence Function Nonlinearity Worst
Nonlinearity
Iteration
Function
Function
Value
Ratio
Model
Ratio
--------- ----------- ----------- ---------- ------------ -------- -----------0
1.005D-03
0.000D+00 0.000D+00
9.349D-01 RXRG
9.349D-01
1
6.275D-07
0.000D+00 0.000D+00
9.975D-01 RXRG
9.975D-01
2
2.711D-09
0.000D+00 0.000D+00
1.000D+00 RXRG
1.000D+00
3
0.000D+00
0.000D+00 0.000D+00
Successful solution.
Optimization Timing Statistics
Percent
7-8 • EO Modeling Background and Examples
Time
Aspen FCC 12.1 User Guide
================================
=======
========
MODEL computations
33.82 %
DMO computations
56.46 %
Miscellaneous
9.72 %
----------------------------------Total Optimization Time
100.00 %
Updating Plex
Problem converged
7.69 secs
•
•
•
•
•
12.84 secs
2.21 secs
---------
---
22.74 secs
Iteration is the count of SQP iterations (QP subproblems)
performed by the solver. There is one line of output for each
normal iteration of the solver. Abnormal iterations may have
additional lines for error or information messages.
Residual Convergence Function indicates the solver’s
progress towards solution, in terms of feasibility of the
residuals. The problem does not converge until this measure
gets below the value of solver setting rescvg defined in the EB
script for that solution mode.
Objective Convergence Function is a measure of the solver’s
progress towards solution in terms of optimality of the
objective function. This is only meaningful in modes with
degrees-of-freedom, which is only the optimization mode in
Aspen FCC. The problem does not converge until this measure
gets below the value of solver setting objcvg defined in the
EB script for that solution mode.
Objective Function Value refers to the Jacobian of the
objective function.
Nonlinearity Ratio is a measure of the nonlinearity of the
problem. The closer the value is to one, the more linear the
problem. A negative value indicates that the problem behaved
in the opposite way to what was expected. Near the solution, as
the step sizes become small, this value becomes close to one.
There are two nonlinearity ratios – Overall and Model.
The last section of the output shows the execution times for the
various parts of the problem.
In this example, we can see that convergence was achieved when
the residual and objective convergence functions were less than
their respective tolerances at iteration 3.
Aspen FCC 12.1 User Guide
EO Modeling Background and Examples • 7-9
From this output, we also see that there have been no line searches.
Thus, the step size for each iteration is one. When a line search is
performed for an iteration, a message will appear:
<Line Search ACTIVE> ==> Step
taken 3.26D-01
If the solver has to line search continually and the step size gets
very small (less than 1.0D-2), most likely the solution is trying to
move very far from the starting point, or some of the specified
values are nearly infeasible.
DMO Solver Log Files
Aspen FCC outputs DMO solver information to two log files
• ATSLV
• ATACT
These files reside in the working directory you defined in the
startup menu box.
The ATACT file is similar to the ATSLV file, but lists all the
problem variables and independent variables, whereas the ATSLV
file does not. The ATSLV file is typically more useful and is
described in more detail below.
ATSLV File Problem
Information
At the top of the ATSLV file, a summary of the problem is
printed. This shows the size of the problem and the values of some
important parameters.
Model or plant name
Solution case
Number of variables
Number of equality constraints
Number of fixed variables
Actual degrees of freedom
Number of lower bounded variables
Number of upper bounded variables
Total number of constraints
Maximum number of iterations
Printing frequency
Objective function tolerance
Residual convergence tolerance
Derivative perturbation size
Solution mode
Maximum number of models
Maximum number of soft bounds
Time of run
Date of run
Basic Iteration
Information
RXRG
SIMULATE
127927
111876
16051
0
127927
127927
367730
50
-1
1.0D-06
1.0D-06
1.0D-06
NORMAL
3000
1500
21:41:58
25-NOV-2001
At each iteration, the following header is printed, showing the
iteration number and the value of the objective function:
+----------------+
| Iteration
0 |
+----------------+
7-10 • EO Modeling Background and Examples
Aspen FCC 12.1 User Guide
Objective Function
0.0000E+00
Largest Unscaled
Residuals
=>
This section shows the largest unscaled residuals. A similar section
shows the largest scaled residuals. This section is particularly
helpful when the solver has trouble closing all the residuals
because it will list the largest ones.
Shadow
Index Most Violated UNSCALED Residuals
Residual
Price
====== ======================================= ============ =============
73676 RXRG.BLKEQN_YLDES_TBP_FOE_VALUE_BIAS_CAL 1.81662D+01 -2.37348D-19
108234 RXRG.BLKEQN_CXN_EQN___33328_X(119459)_=> -1.42249D+01 -2.29209D-19
47799 RXRG.BLKEQN_CUT3VF_VAPOR_SPL_FAC_10
1.00000D+00 -8.08521D-16
47796 RXRG.BLKEQN_CUT3VF_VAPOR_SPL_FAC_7
1.00000D+00 -1.64365D-18
47790 RXRG.BLKEQN_CUT3VF_VAPOR_SPL_FAC_1
1.00000D+00 -4.64051D-17
47798 RXRG.BLKEQN_CUT3VF_VAPOR_SPL_FAC_9
1.00000D+00 -2.75911D-15
47797 RXRG.BLKEQN_CUT3VF_VAPOR_SPL_FAC_8
1.00000D+00 -1.38725D-15
47791 RXRG.BLKEQN_CUT3VF_VAPOR_SPL_FAC_2
1.00000D+00 -3.41395D-17
47793 RXRG.BLKEQN_CUT3VF_VAPOR_SPL_FAC_4
1.00000D+00 -3.80201D-17
47792 RXRG.BLKEQN_CUT3VF_VAPOR_SPL_FAC_3
1.00000D+00 -3.80206D-17
Constrained Variable
This section shows the variables that lie on their bounds. This is
only meaningful in a degree-of-freedom mode (optimization for
Aspen FCC).
The output shows the variable number, which bound is active, the
variable name, the current value, and the shadow price. The
shadow price is also known as the Lagrange multiplier. This is the
derivative of the objective function with respect to the value of the
constraint and represents the cost for the constraint.
Projected Active Constraints
Shadow
Index
for the Next Iteration
====== =======================================
949 Upper Bnd C2SDDEF.SPC.MOLEFR.C2H6
Bound
============
2.00000D-04
Price
=============
-4.32924D+02
The shadow price is based on the value of the objective function
that is seen by DMO. That means the shadow price is in SI units
(such as $/sec) and is affected by any scaling. This is true even if
you declare the units to be something other than SI (such as $/hr).
Consider this example. We have a tower with a composition
constraint, expressed as a mole fraction of a component. The
following table shows the results of two optimization runs at two
different values of the composition constraint:
Constraint Value
Objective Function
Shadow Price
0.0002
0.0003
2.853
2.893
432.924
258.664
The large change in the shadow price indicates that the effect of
the composition on the objective function is very nonlinear. We
can manually estimate the average shadow price in this region by a
finite difference method:
Aspen FCC 12.1 User Guide
EO Modeling Background and Examples • 7-11
Price = ∆Obj/∆x = (2.893 – 2.853) / (0.0003 – 0.0002)
= 400.00 $/sec/mole fraction
This value lies between the two prices.
If the objective function had a scale factor of 100, we would get
the following:
Constraint Value
Objective Function
Shadow Price
0.0002
0.0003
285.4
289.3
43290.7
25860.2
We would have to remember to unscale the shadow price by
dividing by 100.
General Iteration
Information
This section appears after the residual output:
Iteration status
Degrees of freedom
Constrained variables
Current degrees of freedom
Number of function evaluations
Number of Jacobian evaluations
Objective function convergence function
Residual function convergence function
LU decomposition time (seconds)
Search direction time (seconds)
=>
=>
=>
=>
=>
=>
=>
=>
=>
=>
Normal
0
0
0
0
1
0.00000D+00
1.00550D-03
7.38D+00
8.28D+00
The Iteration status shows the exit condition of that iteration.
Iteration status
Indicates
Normal
Warning
Error
Solved
A normal successful iteration
A successful iteration despite some solver difficulties
A failure
The final iteration of a successfully solved problem
The Degrees of freedom is the number of declared independent
variables in the problem. The Constrained variables are the
degrees of freedom at bounds in the QP subproblem. The Current
degrees of freedom are the degrees of freedom less the
constrained variables. This is the true number of degrees of
freedom for the problem. A highly constrained solution is one that
has very few current degrees of freedom.
The Number of function evaluations and Number of Jacobian
evaluations are accumulative counts and generally match the
number of iterations.
The Objective function convergence function is the norm of the
Jacobian for the objective function. At the solution, this value
should be near zero.
The Residual function convergence function is the sum of the
scaled residuals. At the solution, this value should be near zero.
Nonlinearity Ratio
This section shows the nonlinearity ratio of the worst block, the
objective function, and the worst equations. The criterion is the
7-12 • EO Modeling Background and Examples
Aspen FCC 12.1 User Guide
accuracy of the predicted change in the equation. If the function is
linear, then the new value would match the predicted value and the
nonlinearity ratio would be one. A value of the ratio other than one
indicates some degree of nonlinearity. A negative value indicates
that the function value moved in the opposite of the expected
direction. Large negative values could indicate a discontinuity or
bad derivative.
This section also shows the step size for the iteration.
Model nonlinearity ratios =>
---------------------------RXRG
=
0.93489
Model nonlinearity ratios of
1 model(s) between
Objective function nonlinearity ratio
Non-Linearity Report for Iteration
=>
1.01
1.0000
1 : Step Fraction =
Index
Worst Equation Non-Linearity Ratios
===== ========================================
45441 RXRG.BLKEQN_CUT1ANLZ_ABP625A______WTPCT
47648 RXRG.BLKEQN_CUT3ANLZ_ABP725A2_____WTPCT
47647 RXRG.BLKEQN_CUT3ANLZ_ABP725A1_____WTPCT
57609 RXRG.BLKEQN_NAPHSNL_MOLES_ABP325A
45452 RXRG.BLKEQN_CUT1ANLZ_ABP725A2_____WTPCT
Aspen FCC 12.1 User Guide
0.99 and
1.00000D+00
Ratio
============
-1.47131D+01
1.32713D+01
1.32712D+01
-7.53478D+00
-7.29881D+00
Deviation
============
1.57131D+01
1.22713D+01
1.22712D+01
8.53478D+00
8.29881D+00
EO Modeling Background and Examples • 7-13
7-14 • EO Modeling Background and Examples
Aspen FCC 12.1 User Guide
CHAPTER 8
Troubleshooting
Aspen FCC Stops Responding
Occasionally, problems can occur where the AspenFCC menu
commands and toolbar are still active, but the functions fail with
various VB errors. This can be the result of loading too many
applications at once, thereby causing an application conflict. The
spreadsheet has lost the connection to the model, but the model is
still in the memory of the computer. If this happens, the connection
to Aspen FCC flowsheet can be reset and then a new connection
established. A new connection should not be made until the reset
command has been issued.
Resetting Connection to the Aspen
Plus Server
To reset the connection to the Aspen FCC flowsheet:
• Click AspenFCC | Startup Aspen FCC | Reset ApMain as
shown below.
Aspen FCC 12.1 User Guide
Troubleshooting • 8-1
To establish a new connection to the Aspen FCC flowsheet:
• Click AspenFCC | Startup Aspen FCC | Load FCC Flowsheet.
Error Recovery for Parameterization
You should check the convergence status shown at the top of the
Param sheet after running the parameter case. The results on the
Param and Analysis sheets are only meaningful if the
convergence status is converged. If the status is not converged,
then you should return the Param sheet and model to their presolution states.
To return Param sheets and models to their pre-solution
states:
1 Click AspenFCC | File | Load Case Data to restore the model
to a converged parameter case.
2 If this is your first attempt at running a Param case, then load
user_default.var or the . var file created by AspenTech for
your site.
-orIf you have converged Parameter cases for your unit, then
load the corresponding . var file that most closely represents
the process conditions and input data for the new parameter
case.
3 Click AspenFCC | File | Load User Input Sheet to restore the
Param sheet user input.
Examine the input data as compared with the base parameter case.
Convergence failure for the Parameter case typically has one of
three basic causes:
1 Poor or erroneous data were entered as input (blue-colored
cells). For example:
• Check that physically realistic property data were entered
for all feeds and products. For example, all distillation
points must increase as a function of percent distilled.
• Check that physically realistic property data were entered
for all catalysts. For example, the ECAT activity must
always be lower than fresh activity.
• Check that physically realistic mechanical data were
entered. For example, the regenerator cyclone height must
be greater than the bed height.
2 Some of the input data violate valid ranges. Such restrictions
are a consequence of the equation-based manner in which the
8-2 • Troubleshooting
Aspen FCC 12.1 User Guide
3
model has been formulated. Observe the following guidelines
when entering data:
• Do not set any recycle rate to zero. For zero recycle rates,
use a very small number instead (for example, 0.1 BBL/D).
• Fraction to riser bottom: The midriser feed rate must be
nonzero. If the midriser feed rate is in fact zero, set the
fraction to riser bottom for feed 1 equal to 0.999999.
• Data restrictions for light-ends analyses:
− Compositions for any one stream must not sum to zero,
including streams having a zero flow rate.
− For the light and heavy naphtha streams, all C5+
components must be nonzero, again including any
stream having a zero flowrate.
− For any one component, the sum of its composition
across all streams must not be zero.
• Do not enter zero for any flue gas component.
The solver parameters are too aggressive for the data entered.
For example, a large change in feed rate (greater than 15%)
may require more conservative solver parameters. For more
information about solver parameters and strategy, see
Changing DMO Parameters. on page 7-8.
Error Recovery for Simulation
Check the convergence status shown at the top of the simulation
sheet after running the simulate case. The results on the simulation
sheet are only meaningful if the convergence status is converged.
If the status is not converged, then you should return the simulation
sheet and model to their pre-solution states.
To return simulation sheets to their pre-solution states:
1 Click AspenFCC | File | Load Case Data to restore the model
to the base Parameter case.
2 Browse for the .var file in which you saved the results of the
base Parameter case.
3 Click AspenFCC | File | Load User Input Sheet to restore the
Simulation sheet user input.
Examine the input data as compared with the base Parameter case.
Convergence failure for the simulation case typically has one of
two basic causes:
1 Poor or erroneous data were entered as input (blue-colored
cells). For example:
Aspen FCC 12.1 User Guide
Troubleshooting • 8-3
•
2
Check that reasonable feed property data were entered for
all feeds.
• Check that reasonable catalyst property data were entered
for all catalysts.
• Check that the cut points entered for light naphtha and LCO
are physically possible.
The solver parameters are too aggressive for the data entered.
For example, a large change in feed rate (greater than 15%)
may require more conservative solver parameters. For more
information about solver parameters and strategy, see
Changing DMO Parameters. on page 7-8.
Solver Performance
This section describes some troubleshooting tips to improve the
performance of the solver and to help diagnose common problems.
Dealing with Infeasible
Solutions
These often occur during optimization cases where it is not
possible to simultaneously solve all the equations while respecting
all the variable bounds. This doesn't happen in simulation cases
because DMO ignores bounds in simulation cases. If you solve a
simulation case that violates a bound, then the optimization case
will start at an infeasible point. A message like the following will
be printed in the ATSLV file:
Information => QP step for variable
1157:
C2SDDEF.SPC.MOLEFR.C2H6
was adjusted to satisfy its UPPER
bound = 2.0000000E-04
The size of QP step violation was
= 2.5673465E-04
This variable's value had to be adjusted to respect the bound. When
the optimization proceeds and there is no feasible solution for the
equality constraints, the screen output might look like this:
Residual
Objective
Model
Convergence Convergence
Nonlinearity Worst Nonlinearity
Iteration
Function
Function
Ratio
Model
Ratio
--------- ----------- --------------- ------- -----------Warning ... QP slack variable =
Warning ... QP slack variable =
0
9.312D-04
4.809D-03
9.968D-01 C2S
-2.834D-01
Warning ... QP slack variable =
Warning ... QP slack variable =
Objective
Overall
8-4 • Troubleshooting
Function
Value
---------- ------2.29070D-01
2.29070D-01
-2.779D+00
1.80624D-01
1.80624D-01
Aspen FCC 12.1 User Guide
1
5.244D-04
4.667D-02
2.900D-01 C2S
-1.846D+02
Warning ... QP slack variable =
Warning ... QP slack variable =
2
1.552D-02
5.479D-02
7.475D-01 C2S
-1.540D+01
Warning ... QP slack variable =
Warning ... QP slack variable =
3
3.853D-02
2.379D-03
9.908D-01 C2S
9.914D-01
Warning ... QP slack variable =
Warning ... QP slack variable =
4
1.496D-02
1.040D-02
8.346D-01 C2S
6.012D-01
Warning ... QP slack variable =
Warning ... QP slack variable =
-2.792D+00
1.44771D-01
1.44771D-01
-2.922D+00
-
6.09502D-01
6.09502D-01
-3.083D+00
1.87163D-01
1.87163D-01
-3.075D+00
3.18508D-01
3.18508D-01
+---------------------- ERROR ---------------------+
Error return from [DMO] system
subroutine DMOQPS
because the problem has NO FEASIBLE
SOLUTION.
Action : Check the bounds that are
set on variables
to insure consistency.
Check the .ACT file
for information on initial
infeasibilities.
+--------------------------------------------------+
Error return, [DMO] System Status Information =
Optimization Timing Statistics
Percent
================================
=======
MODEL computations
31.10 %
DMO computations
21.28 %
Miscellaneous
47.61 %
-----------------------------------Total Optimization Time
100.00 %
Updating Plex
Problem failed to converge
Aspen FCC 12.1 User Guide
5
Time
========
1.32 secs
0.91 secs
2.03 secs
---------
--
4.26 secs
Troubleshooting • 8-5
Note the messages from the QP indicating an invalid value for a
slack variable.
To solve this problem, you need to be aware of the initial message
indicating that the initial value of a variable violated its bound. In
this case, C2S.SPC.REFL_RATIO_MASS is causing the
problems. Unfortunately, the ATSLV file does not list this variable
as constrained, since it could never solve the QP successfully.
Scaling
Generally, it is not necessary to scale your equations or variables
beyond what is done by default in the models. However, it may be
more efficient to scale your objective function. A good rule of
thumb is to scale the objective function so that its value is on the
order of 10 to 1000. The scaling of the objective function plays an
important role since it affects the overall convergence behavior.
This is particularly important in cases where there is a large change
between the original value of the objective and the expected
optimum.
Dealing with Singularities Singularities often occur when the model is moved into a region
where the equations are not well defined. The most common
example of this is when a stream flow becomes too small. If
singularities exist, they are usually detected at the start of the
problem. In this case, some information is written to the ATSLV
file and this can help locate the cause of the problem. In general,
you should prevent stream flows from going near zero by placing
nonzero lower bounds on the flow (for example, 10 kg/hr). This is
especially important on streams from flow splitters or feed streams
whose total flow is being manipulated. In the case of a singularity
the following message will be displayed:
+-------------------- WARNING ----------------------+
A NUMERICALLY SINGULAR matrix is detected during
the ANALYSIS phase of LU decomposition.
The number of dependent equation set(s) detected =
1
Check the output file for more information.
+---------------------------------------------------+
The ATSLV file contains information on the possible cause of the
singularity in the following manner:
+-------------------- WARNING ----------------------+
A NUMERICALLY SINGULAR matrix is detected during
ANALYZE phase of LU decomposition.
WARNING: The dependent equation set is NOT unique.
It depends on the options for performing
LU decomposition.
==> Dependent equation set:
8-6 • Troubleshooting
1
Aspen FCC 12.1 User Guide
The partial derivatives of the following
equations with respect to variable
1: Strm 1 moles lbmol/h
in the reduced matrix are zero.
Equation ->
10: Enthalpy balance M
Btu/lbmol
is a function of the following variables:
1: Strm 1 moles lbmol/h
= 0.00000D+00
-> Calc
4: Strm 1 enth M Btu/lbmol
= -7.45977D+01
-> Const
12: Strm 2 moles lbmol/h
= 0.00000D+00
-> Const
15: Strm 2 enth M Btu/lbmol
= -7.45977D+01
-> Const
23: Heat loss MM Btu/h
= 0.00000D+00
-> Const
25: Prod moles lbmol/h
= 8.93760D-07
-> Calc
28: Prod enth M Btu/lbmol
= -7.45977D+01
-> Calc
->
->
->
->
->
->
Equation ->
9: Prod C9H20_1
mf
is a function of the following variables:
1: Strm 1 moles lbmol/h
= 0.00000D+00
Calc
10: Strm 1 C9H20_1
mf
= 4.52017D-01
Const
12: Strm 2 moles lbmol/h
= 0.00000D+00
Const
21: Strm 2 C9H20_1
mf
= 4.52017D-01
Const
25: Prod moles lbmol/h
= 8.93760D-07
Calc
34: Prod C9H20_1
mf
= 4.52017D-01
Calc
Sometimes, singularities are simply caused by the optimization
being too aggressive. This moves the models into a region where
the equations are not well defined. To make the optimization more
robust, DMO has a creep mode. This mode simply causes smaller
steps to be taken for a specified number of iterations. To use this
mode, you can enter the following script command:
SOLVER SETTINGS CREEPFLAG = 1
This turns on the creep mode. When active, the following message
is displayed at each iteration:
<Line Search Creep Mode ACTIVE> ==> Step
taken 1.00D-01
By default, this will operate for 10 iterations with a step size of 0.1.
You can change these values with the commands:
SOLVER SETTINGS CREEPITER = 20
SOLVER SETTINGS CREEPSIZE = 0.5
Aspen FCC 12.1 User Guide
Troubleshooting • 8-7
In this example, we change the number of creep iterations to 20
and the step size to 0.5.
Notes on Variable
Bounding
Remember that by default DMO does not respect bounds during
the solution of a Simulation or Parameter case. You, however,
have the capability to impose bounds in a square case by using a
different line search parameter. The use of this mode is
recommended only in cases where
• There are truly multiple solutions to a model (for example, the
cubic equation).
• You want to use a bound to eliminate an unwanted solution.
To use this mode, you can enter the following script command:
SOLVER SETTINGS LINESEARCH = 4
In general, it is not recommended to heavily bound an optimization
problem for reasons that are both practical and algorithmic.
Bounds on independent variables are recommended in order to
avoid unbounded problems. All other bounds should be used only
if they are absolutely necessary. Finally, redundant bounds should
be avoided.
Run Time Intervention
During long runs, it is possible to change the behavior of the DMO
solver. This is done by clicking one of the three buttons at the
bottom of the command window. The selection will take effect at
the start of the next DMO iteration. For more information on these
buttons, see Command Line Window. on page 3-1
The Model Is Not Solving
If the new data are very different from the starting point, it may be
difficult for the model to solve. If the residuals are very large and
the non-linearity is very poor, it is possible that the model will be
unable to solve. Rather than waiting for a large number of
iterations, you can terminate the solution by clicking the Abort
button on the Command Line window. This will stop the model
from solving, but not reset the memory to the starting point before
a solution was attempted. It is possible that a saved solution will
need to be loaded into memory so that the model will be able to
reach a solution. For this reason, it is very important to save
parameter case results using the Save Case Data command, so that
you can load in a valid starting point without needing to use the
Reset ApMain option previously discussed.
After re-loading good data from a saved file, try running the failed
case again with an increased number of creep iterations. Review
the section Saving and Loading Case Data. on page 2-3.
8-8 • Troubleshooting
Aspen FCC 12.1 User Guide
Licensing Errors
The following error message may appear if the Aspen Plus license
verification fails.
Message
Error in ConnectServer(), module Com2Dcom.
Error message:Unable to load simulation
engine. License check out error.
Cause
The Aspen Plus license was not found when
attempting to connect to the Aspen FCC flowsheet.
Solution
Check to make sure that the license server or the
license file has been selected properly. See the
Licensing section on page 2-10 of the Aspen
RXfinery Installation Manual for more information.
Ensure that the licenses for Aspen Plus, Aspen Plus
EO Optimizer, and the Aspen RXfinery application
have been entered into the license server or are
located in the license file.
The following error message may appear if the Aspen FCC license
verification fails.
Message
****EXECUTION ERROR WHILE EVALUATING
RESIDUALS FOR UNIT OPERATIONS BLOCK:
"RXRG" (MODEL: "USER3")
LICENSE VALIDATION/CHECKOUT
FAILURE FOR ASPEN FCC
Cause
The Aspen FCC license could not be found in the
license server or license file selected.
Ensure that the license key for Aspen FCC has been
entered into the license server or is located in the
license file. See the Licensing section on page 2-10
of the Aspen RXfinery Installation Manual for more
information.
Aspen FCC 12.1 User Guide
Troubleshooting • 8-9
8-10 • Troubleshooting
Aspen FCC 12.1 User Guide
CHAPTER 9
The FCCU Model
The FCCU Model
The offline model for the FCC is a complete system for modeling
an FCC. It includes a feed system, a regenerator, a reactor, slide
valves, risers, standpipes, and cyclones. Furthermore, it contains an
approximate representation of a gas plant. This simplified gas plant
(GSP) is suitable for obtaining quantitative estimates of the gasplant products fractionated from the reactor effluent. The FCC
model also includes a number of models to account for coke
formation and its transmittal through the mass flow paths. Models
for handling the distribution of feed sulfur and nitrogen among the
gas plant products are also provided.
Twenty-One-Lump Kinetics
Riser conversion kinetics are derived from the Mobil ten-lump
mechanism. Aspen FCC has expanded the number of
reactant/product lumps to 21 and changed the functionality of
several key lumps. The reactions themselves are all based on wellunderstood first order kinetics that all occur in the vapor phase.
The kinetic expressions are integrated along the length of the riser
and are dependent on the catalyst bulk density, coke on catalyst,
MAT activity, basic nitrogen, and metals content. The MAT
activity and basic nitrogen are entered from external model sources
and affect the riser kinetics uniformly. The catalyst bulk density
and coke on catalyst are also integrated along the riser length and
are themselves a function of pressure drop, coke make, and molar
expansion. The pressure drop includes elements of head, friction,
and acceleration.
All kinetics in the reactor are based on the 21-lump kinetic system.
The reaction pathways represent paraffinic cracking, naphthenic
ring opening, alkyl side chain cracking, ring condensation, kinetic
Aspen FCC 12.1 User Guide
The FCCU Model • 9-1
coke make from typical condensation reactions, and metals coke
make due to dehydrogenation. The reaction paths have been
logically grouped to make yield parameterization more convenient.
Thus all the pathways which lead to gas make up one class, the
gasoline pathways make up another class, and so on. In this way,
with only a small number of yield measurements off the operation
unit, the kinetic rate parameters for the more than fifty reaction
pathways can be easily tuned to match the unit yields. To match
the specific product compositions that are observed on the unit
(provided that information is available), additional tuning of
paraffinic and aromatic reaction rates must be performed.
This system divides the reactants and products into lumped
aggregates of material classified by chemical type and boiling
point range. These lumps are similar to pseudo-components but are
based on molecular structure in addition to the boiling range for
typical pseudo-component breakdowns. The molecular structures
selected are based on likely reaction pathways and mechanisms
understood to exist in fluid catalytic cracking chemistry. The table
below summarizes the lumps used in the model. These lumps are
classified into paraffinic, naphthenic and aromatic chemicals and
each of these types is divided into four boiling point ranges as
shown in the table. Aromatics are further divided into substituent
carbons and ring aromatic carbons.
The components were also selected to represent convenient boiling
ranges that represent yields of light gases, gasoline, light cycle oil,
heavy cycle oil, and the main fractionator bottoms (which also
include any remaining resid). The light gas components represent
all light gases from H2 to C5 The gasoline component represents
the component range from C5 to 430 °F.
There are three lumps that are not identified with a particular
chemical type:
• C lump
• Kcoke lump
• Mcoke lump
The C lump is used to calculate the light gases for methane through
the pentanes. This is based on a correlation using the C lump
produced in the kinetic paths and the composition of the feed.
Kcoke is kinetic coke, the coke routinely produced through
cyclization and condensation pathways. Mcoke is metals coke, the
coke produced as a by-product of dehydrogenation reactions
caused by the presence of active Ni equivalent on the catalyst.
9-2 • The FCCU Model
Aspen FCC 12.1 User Guide
Twenty-One Lump Model
No.
Lump
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
C
G
Pl
Nl
Ar1l
Ar2l
Asl
Ph
Nh
Ar1h
Ar2h
Ar3h
Ash
Rp
Rn
Ra1
Ra2
Ra3
Ras
Kcoke
Mcoke
NBP Range
< 430 °F
430 – 650 °F
650-950 °F
> 950 °F
N/A
Description
C lump – produces light gases
Gasoline Lump C5
Light Paraffins
Light Naphthenes
Light 1-Ring Aromatics
Light 2-Ring Aromatics
Light Aromatic Ring Substituent Carbons
Heavy Paraffins
Heavy Naphthenes
Heavy 1-Ring Aromatics
Heavy 2-Ring Aromatics
Heavy 3-Ring Aromatics
Heavy Aromatic Ring Substituent Carbons
Resid Paraffins
Resid Naphthenes
Resid 1-Ring Aromatics
Resid 2-Ring Aromatics
Resid 3-Ring Aromatics
Resid Aromatic Ring Substituent Carbons
Kinetic Coke
Metals Coke
The aromatic carbon classification helps to account for those
carbons that can be cracked into the gasoline range material and
those that do not crack as easily. Ring carbons are those carbons
that make up the aromatic structure and, therefore, are less likely to
crack into lighter material. Instead, they participate in ring
condensation reactions that eventually can lead to coke formation
on the catalyst. Substituent carbon atoms are the paraffinic
substituent atoms on the core aromatic structures. They include
paraffinic carbon chains of varying lengths and combinations that
are distributed around the core aromatic structures.
The table above illustrates how the chemicals going into the FCC
model are lumped. First, there is a division by boiling point. Then,
there is a division by chemical type:
• Paraffinic
• Naphthenic
• Aromatic
Aspen FCC 12.1 User Guide
The FCCU Model • 9-3
The aromatics are further broken down into substituents and core,
or ring carbons. Therefore, a chemical such as n-butylbenzene has
6 core C atoms and 4 substituent carbon atoms. Carbons in
hydroaromatic structures, where a saturated ring is fused to an
aromatic ring, are counted as substituent carbon atoms.
Tetrahydronaphthalene is an example of a hydroaromatic structure.
Schematic for the 21-Lump Reaction Paths
The lumped species participate in a heterogeneous reaction
network of temperature and catalyst dependent pathways. This
network of kinetic pathways is shown above.
In this figure, each arrow proceeding from one species to another
represents a kinetic path. Since the reaction rates are represented
by Arrhenius type expressions, each path has associated with it a
frequency factor and activation energy. Within the kinetic system,
the C lump component is divided directly into ten individual lightgas components and coke. This 21-lump model also carries along a
separate coke lump that includes coke brought in with the feed.
Direct resolution of the C lump into the light chemical species is
accomplished by a correlation adapted for the 21-lump model. For
online optimization, these correlation coefficients are treated as
parameters and fit to any measured data that exist for these species.
This data may be in the form of analyzers, inferentials, or
laboratory Gas-Liquid-Chromatography (GLC) data for the light
products. These products generally include the dry gas,
9-4 • The FCCU Model
Aspen FCC 12.1 User Guide
depropanizer overheads, and debutanizer overheads. They are
represented by the chemicals:
1 Hydrogen
2 Methane
3 Ethylene
4 Ethane
5 Propylene
6 Propane
7 Iso-butane
8 Butenes
9 n-Butane
10 Iso-pentane
11 Pentenes
12 n-Pentane
Light and Heavy Lump Types
After the amounts of these chemicals are determined from the
correlation, the riser effluent is split up into even finer
compositional detail. This split of the C4=, C5=, iC5, and the C6 to
430 °F gasoline are split into the isomers listed below. The amount
of each isomer created is determined by fixed ratios or split factors.
The ratios are tuned to match a particular unit by adjusting split
Aspen FCC 12.1 User Guide
The FCCU Model • 9-5
factors for each isomer. The source component, split components,
and split factors are determined in a parameterization run.
Isomer Creation from Split Factors
Source Component
Split Out Components
C4=
Iso-butene
1-Butene
Cis-2-butene
Trans-2-butene
1,3-butadiene
Iso-pentane
Cyclo-pentane
3-methyl-1-butene
1-Pentene
2-Methyl-1-butene
Cis-2-pentene
Trans-2-pentene
2-Methyl-2-butene
Cyclo-pentene
Isoprene (2-methyl-1,3-butadiene)
Benzene
C6-430 G Lump (no benzene)
iC5
C5=
C6-430 G Lump
Sulfur Distribution
In the FCC model, feed sulfur is distributed into standard and
fractionated products based on reaction and fractionation models.
The model contains methods for distributing the sulfur by boiling
point. These distributions permit the prediction of sulfur in the
various products created by the GSP.
Sulfur entering the FCC unit is defined by the following for each
fresh feed:
• Fresh feed rate
• Fresh feed sulfur content as wt%
• Feed sulfur crackability factor
The fresh feed rates and sulfur contents define the total rate of
sulfur entering the FCC. The individual fresh feed data is mass
blended to produce blended values for the sulfur content and
crackability factor.
The sulfur crackability factor defines the propensity of the sulfur to
crack to H2S or remain as compounds in heavy liquid products.
This factor ranges from zero to one. Zero will maximize cracking
9-6 • The FCCU Model
Aspen FCC 12.1 User Guide
to H2S. One will minimize cracking to H2S and force the sulfur to
appear in the heavier liquid products. For example, virgin gas oil
will have a value of zero since most of its sulfur will crack to H2S.
On the other hand, a hydrotreated gas oil will have a value of one,
since most of the easily-crackable sulfur has been removed by the
hydrotreater and the remaining refractory sulfur will pass through
the FCC and appear in cycle oil cuts. The intent is to provide a
factor that shows the difference between alkyl sulfides and
thiophenes in the feed. Sulfides tend to crack to H2S while
thiophenes remain in high molecular weight structures that
concentrate in the cycle oils.
In reaction models, sulfur is distributed into the following standard
products:
• H2S
• C5 to 430 naphtha
• 430 to 650 LCO
• 650+ bottoms
• Coke (burned to SOX in the regen model)
Correlations distribute feed sulfur into these standard reactor
products. The sulfur contents of these products and the %
distribution of feed sulfur into these products are reported on the
Simulation and Analysis worksheets.
The sulfur in the C5-430, 430-650 and 650+ reactor products is
further distributed into the following fractionated products by the
simple fractionation system in the model:
• Light naphtha
• Heavy naphtha
• LCO
• HCO
• Bottoms
The standard product sulfur content is distributed across a sulfur
assay spanning over 100 real and pseudocomponents in the simple
fractionation model. With this sulfur assay, the individual product
sulfurs are developed from stream compositions flowing from the
separation correlations in the fractionation model. In this way, the
product sulfurs show the impact of cutpoint and overlaps in the
real products.
In a parameter case, the real product flows and sulfur contents are
input and used to deduce the standard product sulfur contents. The
resulting standard product sulfurs can then be examined for
reasonableness. In simulation cases (simulation, case study,
Aspen FCC 12.1 User Guide
The FCCU Model • 9-7
optimize), the reactor correlations predict the standard product
sulfurs that are distributed into the fractionated products.
The standard FCC model is setup to represent five real products as
listed above. Even if some of these streams (for example, heavy
naphtha or HCO) do not exist for the current model, reasonable
sulfur values must be entered for these streams that make sense
when compared to the existing streams: light naphtha, LCO, and
bottoms.
Coke Production and Handling
Coke make is separated into five distinct categories:
• Kinetic coke
• Metals coke
• Conradson carbon feed coke
• Non-vaporized feed coke
• Stripper source coke
The Conradson carbon coke and non-vaporized coke are assumed
to be physical types of coke and are therefore deposited on the
catalyst at the entrance of the riser prior to any cracking or coking
reactions. Kinetic coke and metals coke are both determined from
kinetic expressions and are deposited on the catalyst gradually as
reactions proceed through the riser and reactor. The stripper source
coke is determined from the cat/oil ratio and stripper performance
curves.
Kinetic Coke
Kinetic coke make is calculated by the following Arrhenius-type
equation:
Rate (mol feed/hr/vol) = Af * Ai * exp(-Ea/RT)
Where, for kinetic coke:
Variable
Corresponds to
Af
Ai
Ea/R
A frequency for the conversion of 3-ring aromatics to coke
A collection of activities including catalyst activities
An activation energy for the conversion of 3-ring aromatics
to coke
Temperature in °R
T
In Parameter cases, a parameter associated with the coke activities
is determined from a set of test run data from the FCC. This
parameter is a linear multiplier on the kinetic coke rate.
The 21-lump reaction path schematic shows all of the paths that
produce kinetic coke. Each of these paths has associated with it an
Arrhenius type rate expression. Currently, not all of the paths that
9-8 • The FCCU Model
Aspen FCC 12.1 User Guide
produce kinetic coke are used. The paths that are in use reflect the
conversion and involve the following lump types: Nl, Ar1l, Ar2l,
Asl, Ph, Nh, Ar1h, Ar2h, Ar3h, Ash, Ra1, Ra2, Ra3, Ras.
Metals Coke
Metals coke make is calculated by the following equation very
similar to that used for kinetic coke:
Rate (mol feed/hr/vol) = Af * Ai * exp(-Ea/RT)
Where Af and Ai are defined similarly to the kinetic coke activities
except that Ai has a dependence on the active metals on the
catalyst. The term Ea/R is defined by the constant for the 3-ring
aromatic conversion to metals coke and T is temperature in °R.
A parameter is adjusted in a Parameter case to match test run data.
It is a linear multiplier on the metals coke rate.
Feed Source Coke
Feed source coke is determined from the Conradson carbon residue
analysis. The CCR in wt % for all of the feeds is blended on a mass
basis and then the blended feed (including any recycles) CCR is
entered into the riser model. The riser model contains coke
deposition factors due to CCR. There is a riser CCR factor that can
be adjusted to control the deposition of coke. The default value for
this deposition factor is 0.5 and may be reset if analyses indicate
that the default value is not suitable.
Stripper Source Coke
(Occluded Coke)
The stripper source coke is defined as the hydrocarbon entrained
with the catalyst in the stripper and is then transferred to the
regenerator where it appears as coke and is burned. This stripper
coke is relatively high in hydrogen content and this gives a much
higher heat of combustion than the feed and kinetic sources of
coke. Therefore, it is much more detrimental to the regenerator bed
temperature, resulting cat/oil ratio, and finally conversion. Also,
the stripper source coke has roughly the same composition as the
reactor effluent (50% of the hydrocarbon is highly valued
gasoline).
Stripper Source Coke
(Occluded Coke)
For information on fine-tuning the stripper model, refer to Heat
Balance Tuning. on page 6-9.
Initial Vapor Entrainment
The amount of vapor entrained with the catalyst at the top of the
stripper will determine how hard the stripper will have to work to
reduce the hydrocarbon carried over to the regenerator. In essence,
if the stripper operating conditions (pressure, temperature, and
steam rate) were held constant while the amount of hydrocarbon
entrained at the top of the stripper increased, the amount of
hydrocarbon carried over to the regenerator as coke would
increase.
The entrained vapor rate is indicated by the parameter variable
RXSZ_VEffl_Per_Mass_Cat_In in units of (volume of vapor
effluent)/(mass of catalyst). This variable is normally used as a
Aspen FCC 12.1 User Guide
The FCCU Model • 9-9
parameter and is determined by a preconceived notion (estimate)
of the stripper efficiency (variable RXSZ_Stripping_Eff would
thus be a measurement at a typical estimated value of 85%). The
efficiency variable is defined as the percent of hydrocarbon
entering the stripper (from the top) which is removed by the action
of the stripper.
Stripper Performance
Curve Slope
The stripper performance curve is an arbitrary function that is
asymptotic at very high steam/catalyst ratios. The efficiency
increases with steam/catalyst ratio, but as the efficiency
approaches 95%, the rate of efficiency increase begins to taper off.
The slope of the curve, that is (delta efficiency/ delta steam/
catalyst), at efficiencies less than 95% can be changed by setting
the slope for the performance and then re-running Aspen FCC in
parameter mode. A typical value for the slope is 0.5 to 1.0. A
higher value of slope will make the stripper more sensitive to
process changes. In other words, when the catalyst circulation rate
is increased, the incremental amount of coke produced will be
larger when the slope term is higher.
Material Balance Reconciliation
The FCC model performs mass balances in two different ways
depending on the run mode.
In a fitting run (Parameter case), the light naphtha (or debutanizer
bottoms) yield is calculated by difference.
In a predict run (Simulation, Case Study, LP vector, or
Optimization mode), the fresh feeds are distributed among the
products in a simultaneous solution of reaction and heat balance
expressions.
In a parameter case, the mass balance is as follows:
• The fresh feed rates are constant.
• Coke is calculated from air and flue gas data.
• H2S is calculated by difference since feed, naphtha, cycle oil,
and SOX sulfur are specified.
• Pure components H2 through the C5 and C6 components are
specified.
• Heavy naphtha, LCO, HCO, and bottoms yield are specified.
• Light naphtha is by difference.
The parameter case mass balance is displayed at the top of the
Analysis sheet. A positive bias means the feed rate is too low to
match the input yields. The bias is the difference between the input
9-10 • The FCCU Model
Aspen FCC 12.1 User Guide
light naphtha rate and the adjusted light naphtha rate calculated to
force the mass balance.
On the Param worksheet, the light ends yields are entered once for
the pure components using GLC information. However, the heavy
ends yields (naphthas and cycle oils) are entered twice. The first
table is used to generate reaction parameters. The second table is
used to generate separation parameters in the simple fractionation
model. The light naphtha yield is used in the first table to calculate
the measured light naphtha yield. The light naphtha yield is not
entered in the second table since this is the adjusted yield. The
mass balance bias is the difference between these two flows. This
method of parameter case mass balancing is the default system for
the FCC model. In a predict run (simulation, LP vector, case study,
or optimization), the model performs mass balances in a complex
simultaneous solution of the reactor and fractionation expressions.
FCCU Model Configuration
The FCC model is made up of building blocks that model the
components in the FCC. These components include risers, slide
valves, and standpipes along with the regenerator and the reactor.
Riser models solve the kinetic equations along the riser
simultaneously with the equations representing hydraulics and heat
effects. In addition, the models describe coke lay down and entry
zone effects. The pressure balance throughout the reactor,
regenerator, and connecting components is maintained. Pressure
drops are calculated for risers, standpipes, and slide valves.
Throughout the reactor models, the catalyst stream flow includes
mass flow, temperature, pressure, heat capacity (catalyst + coke
mixture), particle density (catalyst + coke mixture), coke on
catalyst weight fractions and coke constituents (C, H, O, N, S) as
atomic weight fractions.
This section discusses briefly the important building blocks of the
FCC model. It first reviews the 21-lump model and then presents
material on the major blocks of the FCC.
Risers
Aspen FCC 12.1 User Guide
Riser models consist of six key ingredients:
• Riser configuration
• Pressure drop
• Hydraulics
• Heat effects
• Coke laydown effects
• Entry zone effects
The FCCU Model • 9-11
The riser model is a segment of the fluidized riser that models the
kinetics in the riser and includes the geometry of the riser for
hydraulic and volume effects. It takes the hydrocarbon feed after
the nozzle exit and combines it with the regenerated catalyst to
take the material to the reactor.
Two-phase pressure drops are calculated through the riser for both
vertically and horizontally configured risers. These orientations use
different correlations for hydraulic effects and pressure drop
calculations. An angle of incline may also be used for the
horizontally oriented models. A pressure drop through the riser is
calculated from three different components: acceleration (kinetic
energy), frictional effects, and gravitational effects. Proper tracking
of hydraulic and pressure effects is necessary to model the changes
in local bulk density correctly. These changes interact with the
kinetics along the riser.
The chemistry in the risers is endothermic and uses the heat
generated in the regenerator for the chemical transformations. This
process is tracked along the length of the riser and is manifested in
the temperature profiles printed in the detailed riser reports. In
these profiles, the temperature of the hydrocarbon catalyst mixture
gradually drops from the entry zone to the riser exit into the
reactor. These temperature drops are used in the models to
determine catalyst flow rates. The net balance of the heat transfers
is summarized in the cracking parameter. This parameter is printed
in custom reports for the risers. If all properties and calculations
were without error, the cracking parameter would be zero.
Generally, it is not zero, but a relatively small number less than
about 10 to 20.
Coke laydown is differentially accounted for by the kinetics along
the length of the riser and the additional solids are transferred from
the vapor phase to the solid phase. These effects are manifested by
the increase in the mass of flowing solids, decrease in the
mass/moles of vapor and the changes in the properties of flowing
catalyst and hydrocarbons. As coke builds up on the catalyst,
deactivation functions are used to lower the activity of the catalyst.
A molar heat of adsorption accounts for heat effects accompanying
the coke laydown. Its counterpart, the heat of desorption, is used in
the regenerator where the coke is burned. Coke is represented by a
combination of H and C in the molar ratio of ½ to 1. This ratio can
be changed in the model if desired.
The riser/reactor system can be configured from the spreadsheet in
the following ways:
• Feed injection points. Fresh feeds and recycles can be injected
at the bottom of the riser or at a mid-riser injection point. Each
9-12 • The FCCU Model
Aspen FCC 12.1 User Guide
•
•
•
•
feed and recycle can be split independently to each injection
point.
Steam injection. Steam can be injected into the lift riser, at the
bottom of the riser and at the mid-riser point.
Lift gas. Lift gas assumed to be 100% N2 can be injected at the
lift riser.
Riser dimensions. Enter riser diameter and length.
Reactor dilute phase dimensions. Enter dilute phase diameter
and height.
The riser/reactor system consists of three models connected in
series as follows:
1 Lift riser
2 Riser first section
3 Riser second section
The lift riser performs a mass and heat balance with pressure drop
calculations but no reactions. Its purpose is to mix hot regen
catalyst with steam and/or lift gas injection and pass this mixture to
the first riser section.
The riser consists of two sections in series. The two riser sections
perform mass balance, heat balance, pressure drop and reaction
calculations. The riser is split to allow the injection of mid-riser
feeds, recycles, and steam. The length of the first section defines
the distance between the riser feed injection nozzles at the bottom
of the riser and the mid-riser injection nozzles. If no mid-riser
injection is present, simply split the riser into two sections about
the same length with zero flow to the mid-riser nozzles.
The dimensions of the lift riser are usually clear with a welldefined diameter and length. The inlet is where the steam, lift gas,
and catalyst mix. The outlet is at the riser feed injection nozzles.
Riser dimensions are also usually clear. For modern FCC units, the
length is about 100 feet, and the diameter should produce inlet
superficial velocities in the 20 to 40 fps range. Ultimately, the
dimensions should generate vapor and catalyst residence times in
the range of 3 to 6 seconds for both riser sections combined. The
residence times and superficial velocities are reported on the
Analysis sheet.
Reactor
Aspen FCC 12.1 User Guide
The reactor model consists of three primary submodels. As the
hydrocarbon mixture enters the reactor vessel, a process of
disengagement of the hydrocarbon and catalyst begins. Cyclone
models are the final stage of this disengagement at the top of the
reactor. Material entering the cyclone models arrives there from
the reactor free-board area. This area is represented by a model that
The FCCU Model • 9-13
sends material, primarily catalyst, to the dense bed of the reactor.
From there the material enters the stripping zone where steam is
used to remove as much of the remaining hydrocarbons as possible
from the catalyst before it enters the spent catalyst transfer line.
Cyclone models use a parameterized, load-based calculation to
entrain a fraction of the effluent hydrocarbon vapor with the
catalyst. This entrained catalyst is sent to the dense bed model. The
fraction of the hydrocarbon not entrained is sent to the overhead
line of the reactor and to the delumper model. It ultimately goes to
the MF as a set of defined chemicals and pseudocomponents.
The reactor dense bed model is a differential-algebraic model that
models performs a single catalytic cracking reaction for the low
concentration of hydrocarbons in the catalyst bed. It also performs
a DP calculation across the height of the bed. This height can be
set using pressure measurements in the plant are be specified
directly in the model. In the latter case, the DP is calculated.
The outlet products of the reactor that proceeds to the stripping
zone are the catalyst and kinetic coke, and a portion of the
entrained hydrocarbon vapor that came down with the catalyst.
Further cracking of the hydrocarbons occurs in the dense bed and
some of this material along with stripping steam proceeds to the
cyclone. There it mixes with the riser effluents that did not entrain
with the catalyst.
Heat balances are performed at each point of mixing in the above
coupled system of cyclones, free board, and dense bed. These
balances yield different temperatures at each point in the system:
riser outlet (cyclone inlet), dense bed, and reactor vessel plenum
(the final effluent).
The reactor dilute phase performs mass balance, heat balance,
pressure drop and reaction calculations. The dilute phase model
represents the reaction volume that exists between the outlet of the
riser and the inlet to the reactor cyclones.
Reactor dilute phase dimensions are murkier. Modern FCC units
have a variety of proprietary designs that attempt to reduce this
residence time to near zero. The dilute phase model assumes a
simple cylindrical geometry with a diameter and length set to
arbitrary values to usually provide a low vapor residence time, that
is, less than one second. Further, the model contains a catalyst
splitter to divert catalyst away from the dilute phase and straight to
the catalyst stripper model. Using the diameter, length, and catalyst
split ratio, you can approximate the performance of the reactor
dilute phase section. A smaller volume and high catalyst split ratio
will minimize the impact of the dilute phase section on model
predictions.
9-14 • The FCCU Model
Aspen FCC 12.1 User Guide
Regenerator
Like the reactor, the regenerator consists of submodels, in this case
the regenerator dense bed, the freeboard (disperse phase), and the
cyclones. Each of these submodels performs heat balance, material
balance and pressure drop calculations.
The regenerator dense bed models a bubbling bed with
heterogeneous coke burn and heterogeneous and homogeneous CO
to CO2 burn. At the inlet, the following are processed:
• Spent catalyst
• Lift air
• Regenerator air (from the main air blower with O2 enrichment)
• Cyclone separated catalyst
It produces at its outlet the following:
• Regenerated catalyst (to the standpipe models)
• Entrained catalyst (to the free board model)
• Combustion gas
Catalyst holdup, or inventory, may be specified or calculated by
specification of bed height and regenerator geometry. This is an
important component of the pressure balance calculation. The
effects of air rate or catalyst circulation depend on how the catalyst
holdup is specified. If the bed height is fixed, then the catalyst
inventory will change. If the inventory is fixed, then the bed height
will change. Since the height of the regenerator is fixed by its
physical dimensions, it follows that when the dense bed height is
allowed to vary, the free board height will vary. These height
changes affect the coke burn and are accounted for in the model
calculations.
The freeboard model represents the section of the regenerator
between the top of the dense bed and the inlet of the cyclones. Its
inlet is the entrained catalyst from the dense bed and the dense bed
combustion gases. It produces for its outlets the freeboard
combustion gases and catalyst stream to the cyclones. The
freeboard model is a plug flow reactor that continues the
heterogeneous coke burn and the homogeneous CO to CO2 burn
(afterburn). Since there is little catalyst in the freeboard region,
further coke burn reactions can produce large temperature changes
from the freeboard to the cyclone inlets.
The regenerator cyclone model performs a two-phase, loadingbased DP calculation for the cyclones. It returns all of the entrained
catalyst to the regenerator dense bed. This sets up a recycle of
catalyst that can alter the steady-state level of coke on regenerated
catalyst and the dense-bed temperature. It reports flue gas
compositions on a standard Orsat dry-mole percent basis.
Aspen FCC 12.1 User Guide
The FCCU Model • 9-15
Stripping Zone Model
The stripping zone model performs the heat, mass, and pressure
balance calculations around the stripping zone. Its inputs are the
stripping steam and the spent catalyst with kinetic coke from the
reactor dense bed. It calculates the stripping steam to the dense
bed, the stripped, slightly cooled catalyst, and the portion of the
stripping steam going into the standpipe and then into the
regenerator.
This model uses a correlation to account for the hydrocarbons
stripped from the catalyst on its way back to the regenerator. This
correlation is in the form of a parameterizable stripping efficiency
curve. It makes use of the mass-ratio of catalyst flow to the
stripping steam flow. The lower this ratio, the better the stripping.
As hydrocarbon is stripped away, the H to C ratio drops. In the
correlation, when the stripping efficiency decreases, the H to C
ratio increases.
Catalyst Standpipe, Slide
Valve and Transfer Line
In the plant, these units transport the spent catalyst with coke
deposits back to the regenerator. In the model, these units serve
this purpose by establishing the links to the catalyst in the reactor.
However, their primary purpose in the model is to set up the
pressure profiles that drive the catalyst back to the regenerator.
Pressure changes in the vertical standpipe as the catalyst goes to
the slide valve are substantial. The hydraulics of this type of flow
are modeled in this unit. In the transfer line, the flow regime is
different, calling for a different set of calculations for the pressure
changes.
FCC Nozzle System
The nozzle system mixes feed with the hot catalyst and removes
heat from the catalyst to heat and vaporize the feed. In the 21-lump
model, this process is complicated by the process of converting
from the detailed component list to the 21-lump components used
in the R/R system. All flashes are based on the detailed component
list. Once the transfer of energy from the catalyst to the full feed is
determined, the final temperature is applied to the 21-lump
composition to determine the equivalent enthalpy for this
compacted component set.
Simple Fractionation
The FCC model contains a simplified fractionation model that
produces realistic naphtha and cycle oil products as observed in the
FCC unit.
The reactor model produces a 19 lump effluent, along with inerts
like steam. Several layers of delumping models expand the 19
lumps to a mix of over 100 real and pseudocomponents suitable for
driving fractionation models. In the FCC model, this stream is
9-16 • The FCCU Model
Aspen FCC 12.1 User Guide
passed to a simplified fractionation scheme. Alternatively, this
stream could also be fed to a rigorous fractionation model in more
complex simulation projects.
The simple fractionation model is a cascade of six stream splitters.
The first splitter removes C3– material from the effluent since this
light material is not needed in the downstream splitters, which are
designed to produce naphtha and cycle oil products. The C4+
effluent is passed to the next splitter, which peels off the bottoms
product. The remaining material then passes to the third splitter,
which peels off the HCO product. Three following splitters operate
similarly to produce LCO, heavy naphtha and light naphtha
respectively. The final splitter produces the light naphtha stream
and a stream of C4s and C5s. The light naphtha contains C4s based
on a C4 content or RVP spec. The C4s and C5s not used to meet
these specs are the final output stream from the splitter cascade.
All of these streams then pass to a custom report model
(ACTYLD) that creates various yield summaries.
The naphtha and cycle oil splitters contain split ratios for each
component to produce the desired bulk product. These split ratios
are based on specialized models that relate empirical separation
factors to the simple splitter component ratios. The separation
factors are similar to vapor-liquid equilibrium ratios. In other
words, for each product, an empirical correlation is used to
generate apparent K ratios that are then used to set the split factor
for each component in the splitter. The result is then a product with
a component distribution that generates distillation curves with
overlaps as normally observed in a commercial unit. In a
Parameter run, these K ratio correlations are adjusted to match the
observed product yields and distillations.
Flow and distillation point targets can be specified for the simple
fractionation products. As these targets are moved, the model will
conserve both mass and volume among the products. Further,
product overlaps will be maintained. However, as the simple
model does not use rigorous thermodynamics or flash calculations,
moving these targets may not track the performance of a
commercial main fractionator. This would require a complex,
rigorous main fractionation model.
The simple fractionation model is hard-coded for five products,
light naphtha, heavy naphtha, LCO, HCO, and bottoms. For
products that are not present in the unit, the flow is set to near zero,
but not exactly zero! For example, if only one naphtha product is
present, that is, debutanizer bottoms, then set the heavy naphtha
flow to a constant low rate like 0.1 MBD and use the light naphtha
inputs for the debutanizer bottoms product. Similarly, if HCO is
not present, set its rate to a constant 0.1 MBD for all cases.
Aspen FCC 12.1 User Guide
The FCCU Model • 9-17
Aspen FCC Input Data Requirements
The data required to tune Aspen FCC includes properties for feeds,
recycles, products, fresh catalyst, and makeup catalyst; operating
conditions (flows, temperatures, and pressures); and mechanical
dimensional data sufficient to calculate reaction volumes and
superficial velocities in vessels, transfer lines, and standpipes. Test
runs are the preferred source of data although routine operating
data, if it has sufficient information, can be quite useful to tune the
model as well.
Feed Blending
The FCC units modeled to date typically have several distinct feed
classes including:
• Virgin gasoils.
• Resid.
• Imported gasoils.
• FCC cycle oils.
• Hydrocracker gasoils.
• Coker gasoils.
Projects have been implemented with and without feed blending
being included as part of the model.
Feed composition changes are taken into account using the feed
bulk inspection properties described below. The total feed to the
unit may be characterized in this way to generate the reactive
component lumps used in model. However, to model the FCC unit
feed selectivity most accurately, adjust individual feed blend
components to match the most recently available bulk property
inspections (list given in the table below). Then blend the resulting
lump compositions together to create a composite feed. Since the
adjustment of the individual feeds results in the creation of detailed
lump compositions for each individual feed, the blended lump
composition is more accurate. When blending feeds, the blended
bulk properties do not provide sufficient information to fully
characterize the feed in detail; detail which Aspen FCC can take
advantage of.
Gas Oil Inspection Properties
API gravity
D2887 distillation
Refractive index (optional, recommended)
Viscosity @210 °F (optional, recommended)
Sulfur
Basic Nitrogen
9-18 • The FCCU Model
Aspen FCC 12.1 User Guide
Conradson carbon (Ramsbottom is optional)
Routine model tuning feed data requirements:
• API gravity
• D2887, D1160, or TBP distillation (D86 is an option but is not
recommended)
• Refractive index and refractive index temperature (optional,
but recommended)
• Viscosity (optional, but recommended)
• Sulfur
• Basic Nitrogen
• Conradson carbon residue (Ramsbottom carbon residue may be
used instead)
Routine model tuning product data requirements:
(Requirements will depend on the refiner’s need for some of these
data.)
• C6– GC For All Light Materials (LN, Light Ends)
• Distillation for LN, HN, LCO, HCO, Slurry
• API Gravity
• Sulfur and Nitrogen for naphthas
• RVP for the lightest naphtha product
• RON/MON for naphthas
• For LCO and HCO
− Cloud Point
− Pour Point
− Sulfur/Nitrogen
− Viscosity
• Overall Plant Material Balance for Tuning Runs
Operating Conditions / Data
Regenerator
• Flue Gas Temperature / Composition (Tuning only)
• Cyclone Temperature(s) (Tuning only)
• Dense Bed Temperature (Tuning only)
• Pressure Profile (Tuning only)
• O2 Injection Rate
• Regenerator Air Rate
• Ambient Temperature and Relative Humidity
Aspen FCC 12.1 User Guide
The FCCU Model • 9-19
•
•
•
Air Blower Performance Curves
Expander Performance Curves
Carbon on Regenerated Catalyst
Riser/Reactor
• Riser / Reactor Temperatures
• Pressure Profile: Reactor Vessel / Stripper
• Stripping Steam Rate / Conditions
• Dispersion Steam Rate / Conditions / Point(s) of Injection
• Lift Steam and Lift Gas Rate / Conditions / Point(s) of
Injection
• Slide Valve Delta P / Positions
• Aeration of Standpipe(s) / Conditions
• Wet Gas Compressor Performance Curves
• Main Fractionator / Gas Plant Data (As Needed by Modeling
Option)
Catalyst Properties / Data
For each of Fresh Catalyst, Purchased Equilibrium Catalyst,
and Equilibrium Catalyst, the following data are required:
• Metals: Ni, V, Na, Cu, Fe
• MAT
• Surface Area
• Bulk Density
• Heat Capacity
• Mean Particle Diameter
• ZSM-5 Content
• Fresh Catalyst Makeup Rate
• Purchased E-Cat Loading Rate
• E-Cat Withdrawal Rate
• Total Unit Catalyst Inventory (Calculated by the model)
Unit Mechanical Data (Initial tuning only)
• Unit Configuration/Type (Dual Riser, Standpipes, Transfer
lines, etc.)
• All Vessel and Transfer Line Lining and Insulation Thickness
and Properties
• All Dimensions and Geometries of:
− Risers
− Reactor
9-20 • The FCCU Model
Aspen FCC 12.1 User Guide
−
−
−
−
−
−
Aspen FCC 12.1 User Guide
Stripper
Regenerator
Cyclones
Slide Valves
Standpipes
Transfer Lines
The FCCU Model • 9-21
9-22 • The FCCU Model
Aspen FCC 12.1 User Guide
Index
1
13C NMR 6-20
19-lump 6-7
1-Pentene 9-6
2
21-lump 9-1, 9-4, 9-11, 9-16
reviews 9-11
21-Lump Reaction Paths 9-1
2-methyl-1 9-1
2-Methyl-1-butene 9-6
2-Methyl-2-butene 9-6
3
33 MBBL/DAY 6-9
rate 6-9, 6-10, 6-11, 6-12
3-methyl-1-butene 9-6
3-ring 6-8, 9-8, 9-9
4
430
C5 9-7
9
9-point 3-17, 3-34
entering 3-17, 3-34
A
Abort 3-2, 5-11
ABORT 3-2
Abort Button 3-2, 6-23, 8-8
Accessing Manually 3-2
Command Line 3-2, 3-3
Excel 3-2
ACT file 8-5
Activating 3-4, 4-8
Aspen FCC 3-4
Optimize 4-8, 4-10, 4-11
Aspen FCC 12.1 User Guide
Actual 3-23
ACTYLD 9-16
Add Properties 4-7
Selected Product Dialog Box 4-5
Add Variables 4-6
Objective Function Dialog Box
4-5
Adding 6-18, 6-19
Catalyst Data 6-19
New Catalysts 6-18
Adjust Fingerprints 6-21
Typical Feed Properties 6-21
Adjusting 3-28
Overcracking 3-28
After 4-7, 4-8, 4-10
Afterburn 9-14
Ai 9-8, 9-9
Air Blower Performance Curves 920
Air Rate 6-4
All Pressures Const 6-3, 6-4
All Use TBP90 6-2
Selecting 6-2
All Vessel 9-20
Ambient Temperature 9-19
Analysis 3-21, 3-24, 3-44, 5-9, 510, 6-1, 6-8, 8-2, 8-6, 9-7, 910, 9-13
Analysis IO 3-44
Analysis Links 3-44
Analysis Sheet Review 6-8
Analysis Worksheet 3-29
ANALYZE 8-6
API 3-16, 3-21, 3-31, 3-34, 5-4, 55, 6-22, 9-18, 9-19
0.88 6-2
Displays 3-30
Including 3-16, 3-34
API Grav 6-21
API Gravity 9-18, 9-19
Apinit 3-5
Ar1h 9-3, 9-8
Ar1l 9-3, 9-8
Ar2h 9-3, 9-8
Ar2l 9-3, 9-8
Ar3h 9-3, 9-8
Aromatic 3-29, 3-30, 3-31, 3-32
Total 3-30, 3-31, 3-32
Aromatic Content 6-7
Aromatic contents 3-29
Arrhenius 9-4, 9-8
Arrhenius-type 9-8
ASCII file 2-4
Asl 9-3, 9-8
Aspen FCC 12.1 4-5
Aspen FCC 1-1, 2-1, 2-2, 2-3, 2-5,
3-1, 3-3, 3-4, 3-6, 3-7, 3-44,
4-2, 4-4, 4-9, 4-11, 5-1, 5-2,
5-3, 5-10, 5-11, 5-15, 6-2, 65, 6-9, 6-12, 6-14, 6-16, 6-18,
6-20, 6-21, 6-22, 6-23, 7-1, 72, 7-3, 7-4, 7-5, 7-6, 7-8, 710, 7-11, 8-9, 9-1, 9-10, 9-18
Activating 3-4
Excel GUI 6-18
Heat Balance Tuning 6-9
Loading 3-1
Re-running 9-10
RXRG 7-8
Starting 2-1
Tuning 5-3, 5-10
Aspen FCC Engine 6-23
Aspen FCC flowsheet 3-3, 8-1, 8-9
Aspen FCC GUI 2-1
opens 2-1
Aspen FCC Input Data
Requirements 9-18
Aspen FCC menu 3-3
Aspen FCC Options 5-4
Aspen FCC Stops Responding 8-1
Aspen FCC toolbar 2-2, 2-3, 2-4, 33, 3-5, 4-1, 5-10, 5-11, 6-10,
6-11, 6-14, 6-16, 6-23
On 2-4, 5-11, 5-12
Update Spec Color button 4-1,
5-10, 6-23
Aspen Plus 2-1, 2-2, 3-2, 3-3, 3-5,
6-23, 8-9
Licensing Errors 8-9
Resetting 2-1
Aspen Plus 12.1 4-4
Aspen Plus Command Line
window 3-1
Aspen Plus EO Optimizer 8-9
Aspen Plus flowsheet 2-1
Aspen Plus Server 8-1
Aspen RXfinery 2-1
Aspen RXfinery application 8-9
Aspen RXfinery Installation
Manual 8-9
Aspen Technology 6-12, 6-21
2 • Contents
AspenFCC 2-1, 2-2, 2-3, 2-4, 3-1,
3-2, 3-4, 3-5, 3-7, 3-9, 3-10,
3-11, 3-12, 3-14, 3-15, 3-16,
3-24, 3-33, 3-38, 4-5, 4-6, 52, 5-11, 6-8, 6-13, 6-24, 8-1,
8-2
Excel menu bar 3-3
Running 3-14
Selecting 2-3, 2-4, 3-1, 3-2, 338, 4-5, 5-11
Setup Cases Submenu 3-9
AspenFCC menu 3-5, 3-8, 5-1, 5-2,
5-9, 5-10, 5-13, 8-1
File Submenu 3-8
AspenFCC toolbar 3-11, 5-10, 5-13
ASTM 3-31
ATACT 7-10
ATACT file 7-10
Atmospheric Tower 3-16
Atmospheric Tower Gas Oil 3-16
Atomizing Steam 3-15
ATSLV 7-10
ATSLV file 7-10, 8-4, 8-6
ATSLV File Problem Information
7-10
Automatic Startup 3-7
B
Back-calculated 6-6, 6-7
Balance 3-15, 6-9
Aspen FCC 6-9, 6-10, 6-11
Regenerator-reactor-wgc 3-15
Base 3-42, 4-5
Basic DMO Parameters 7-8
Basic Iteration Information 7-10
Basic Nitrogen 9-18, 9-19
Basic/Total Nitrogen 3-31
BBL/D 8-2
Bed T 3-13, 5-6
Bed T const 3-12, 5-4
Before You Start 4-2
Behavior 5-14
Changing 5-14
Biases 3-30
WABP 3-30
Blend 6-7
Blocks 9-11
FCC 9-11
Bottoms 3-21, 3-22
Bounds 4-5, 4-8, 4-10
BPD 3-21
BTU/lb 6-8
Bulk Density 9-20
Burned 9-6
SOX 9-7
Aspen FCC
Butenes 9-5
C
C 7-6, 9-11, 9-15
H 9-15
Subject 7-6
C1-C4 3-29, 3-30
C2S.SPC.REFL_RATIO_MASS 84
C2SDDEF.SPC.MOLEFR.C2H6 84
C3– 9-17
C4 3-21, 3-35, 9-1, 9-16
C4 s 3-21, 3-35
Match 3-35
C4 vol 5-4
C4s 9-17
Stream 9-16
C5 3-29, 3-30, 3-35, 8-2, 9-1, 9-6,
9-10
430 9-2, 9-3, 9-5, 9-7
C5 s 3-35
C5 The 9-1
C5-430 9-7
C5-430F 6-8
C5s 9-17
C6 3-20, 9-5, 9-10
C6– GC For All Light Materials 919
C9H20_1
mf 8-7
CA 3-12, 3-31, 6-22
Ca Const 3-12, 5-4
LP 3-12, 5-4
Calc 4-8, 5-9, 7-3, 7-4, 7-5, 8-7
DELTAP 7-4, 7-5
Calc Feed 6-6
Selecting 6-5
Called 7-3
CONST 7-3
Cancel 3-38, 4-2, 5-13
Cancel button 4-8
Carbon on Regen Cat 6-3
Carbon on Regen Catalyst 6-3
Case Study 3-10, 3-14, 3-41, 4-2,
4-3, 4-4, 5-1, 5-11, 6-12, 910, 9-11
Running 4-2, 5-11
Selecting 5-11, 6-12
Case Study menu 5-11
Case Study Worksheet 4-2
Case Type list 5-1
Case Type List-Box 5-1
Case Types 5-1
Cases 3-40, 3-41, 4-2, 5-1, 5-2
Running 5-1, 5-2
Aspen FCC 12.1 User Guide
Cases Worksheet 3-40
Cat Blend 3-44, 5-9, 5-10, 6-8
Cat Blend IO 3-44
Cat Blend Links 3-44
Cat Blend Sheet Review 6-8
Cat Blend Worksheet 3-32
Cat Cooler 3-13, 5-6
Cat/oil 6-9, 9-8, 9-9
Resulting 6-9, 9-9
Catalyst Activity Control 3-14, 5-7
Catalyst Blend 5-9
Catalyst Data 3-23, 3-36, 5-8, 6-7,
6-19
Adding 6-19
Catalyst Makeup versus MAT 6-17
Catalyst Properties 3-32, 9-18
Catalyst Standpipe 9-16
Catalyst Type 6-20
Catalyst1 3-32
Units 3-32
CCR 3-30, 9-9
Changes 3-11, 3-43, 5-8, 5-14, 7-5,
7-6, 7-7
Behavior 5-14
DMO Parameters 7-7
Ready 7-6
Spec 3-10
Specifications 7-4, 7-5
Characterization 3-31, 6-2, 6-5, 620
Check 3-14, 7-7
Options 3-14
Checkboxes 4-2
Selecting 4-2
Chromatograph 3-19
Cis-2-pentene 9-6
Clearing 3-38, 4-10
Checkboxes 3-38, 4-8
Click AspenFCC 4-2, 4-8, 8-2, 8-3
Click Browse 2-3
Click Load 2-4
Close button 3-2, 5-14
Close Residuals 3-2, 5-14
Close Residuals Button 3-2, 5-14
Closing 3-2
Command Line window 3-2
Cloud Point 9-19
CO 3-33, 6-3, 6-4, 9-14
CO2 9-14
Entering 3-33
Setting 6-4
CO const 3-12, 5-4
CO/CO2 3-30
CO2 9-14
CO2/CO 3-33
CO2/CO const 3-12, 5-4
Coke laydown 9-11
Coke Production 9-8
Coker gasoil 6-5, 6-21
Coker gasoils 6-5, 9-18
Column 3-30, 3-32, 4-3, 4-8, 4-9,
4-10
Column B 4-2, 5-12
Column E 5-14
Column G 4-8
Column K 3-32
Column O 3-30
Column R 4-8
Column Y 4-8
Columns C 3-38, 4-8
Com2Dcom 8-9
Combined 3-18
Combo Box Name 3-12
Combo Boxes 7-5
Combo Table 3-44, 7-4
ComboRegistry 3-44
Command 4-5, 4-6
Command Line 3-2, 4-8
Manual Access 3-2
Command Line Window 3-1, 3-2,
5-12, 5-13, 6-23, 6-24, 7-6, 88
Closing 3-2
Command Window 7-8
DMO Solver Output 7-8
Compared 6-7
ECAT 6-7
Model-estimated RI 6-7
Complete Combustion 3-13, 5-5
Composition by boiling range 3-30
Composition by type 3-30
Concarbon 3-29
Connect dialog 3-4, 3-5
Connect Dialog Box 3-5
Connecting 3-1, 3-2, 3-6, 3-10
FCC 3-6, 3-7, 3-8
FCC flowsheet 3-1, 3-2
Options Worksheet 3-10
Connection 8-1
Resetting 8-1
ConnectServer 8-9
Conradson 3-13, 3-17, 3-22, 3-31,
3-34, 5-5, 6-21, 9-8, 9-9, 9-19
Const 3-12, 3-13, 3-14, 4-8, 5-4, 55, 5-6, 5-7, 7-3, 7-4, 7-5, 8-7
CONST/CALC/MEAS/PARAM 74
Constrained 7-12
Constrained Variable 7-11
Constraint Value 7-11, 7-12
Contact AspenTech 3-17, 3-18, 322
4 • Contents
Converged 7-6
Convergence Convergence Function
Nonlinearity Worst Nonlinearity
78, 8-4
Correspond 5-12
LP 5-12
Count 7-9
SQP 7-8
Crack 9-6
H2S 9-6, 9-7
Crackability 6-5, 9-6
CRC 3-13
CRC const 3-12, 5-4
Creep 5-14, 6-24
Creep Button 3-2
Creepflag 5-2, 5-3, 7-8
Creepiter 5-2, 5-3, 7-8
Creepsize 5-2, 5-3, 7-8
CST 3-17, 3-32, 3-34, 6-21, 6-22
CST Factors 3-23, 3-44, 6-19, 620
CST Factors Sheet 3-23
View 3-23
CST Factors Worksheet 6-19, 6-20
Re-hiding 6-20
Unhiding 6-19
Current 7-12
Cutpoint 9-7
Cyclization 9-2
Cyclo-pentane 9-6
Cyclo-pentene 9-6
D
D1160 3-17, 3-31, 3-32, 3-34, 5-10,
6-5, 6-21
D1160 VABP 3-31
D1747 6-21
D2/4 3-24
D287 6-21
D2887 3-17, 3-31, 3-32, 3-34, 6-5,
6-21, 9-18, 9-19
D2887 50 3-30
D4294 6-21
D445 6-21
D4530 6-21
D4629 6-21
D86 3-16, 3-32, 3-34, 6-5, 6-21
D86 90 3-21
D86 End Point 3-21
Data 3-28, 4-1, 5-8, 9-19, 9-20
Entering 5-8
Specifying 4-1
Tuning 3-28, 5-8
Data Files 2-3, 2-4
Loading 2-4
Aspen FCC
Saving 2-3
DCOM 3-44, 6-24
DCS 6-4
Debutanizer 3-12, 3-20, 3-21, 5-4,
6-13, 6-15, 9-10, 9-17
Inputs 9-16
Selecting 6-12
Value 6-12
Decreasing 6-17
MAT 6-17
Default 5-3
10 5-2, 5-3
Degree-of-freedom 7-11
Degrees 7-12
Degrees-of-Freedom 7-2, 7-9
Number 7-2
DELTAP 7-1, 7-2, 7-3, 7-4
CALC 7-5
DELTAP spec 7-4
DELTAP_DEFINITION 7-2
Delumper 6-23, 9-14
Delumping 9-16
Layers 9-16
Dense Bed Temperature 9-19
Description 3-31, 3-32
Heading 3-30, 3-32
Deselect 3-39, 4-10
Deselected 4-2
Desorption 9-12
Heat 9-11
Development Tools 3-3, 3-11, 312, 3-14, 3-33, 6-20
Differential-algebraic 9-14
Dispersion Steam Rate 9-18
Display Command Line 6-23
Display Command Line menu 3-1,
3-2
Displays 3-5, 3-29, 3-30, 3-32
19 3-30
API 3-30
Connect dialog 3-5
MAT 3-32
Matrix Surface 3-32
TBP 3-29
UOP characterization 3-30
Zeolite Surface 3-33
Displays D1160 Volume Average
Boiling Point 3-31
Displays Preheat 3-31
Displays Refractive Index 3-31
Displays Viscosity 3-31
Feed Stock 3-30
Distillation Type 5-8, 6-5
Dk 7-6
DMO 4-5, 5-14, 7-6, 7-7, 7-8, 7-9,
7-10, 7-11, 8-4, 8-5, 8-7, 8-8
Aspen FCC 12.1 User Guide
DMO Parameters 7-7
Changing 7-7
DMO Solver 5-14
DMO Solver Background 7-6
DMO Solver Log Files 7-10
DMO Solver Output 7-8
Command Window 7-8
DMO.MSG 3-2
DMOQPS 8-5
DOF 7-2, 7-4, 7-5, 7-6
Number 7-4
Specify 7-6
DP 6-4, 7-4, 9-14, 9-15
Specifying 7-4
Drawing 3-24
Reactor/Regen 3-26
Dropdown 2-3
Dual Riser 9-18
Dxxx 6-7
E
Ea/R 6-15, 6-16, 6-17, 9-8, 9-9
Value 6-14, 6-15, 6-16, 6-17
Ea/RT 9-8, 9-9
Easily-crackable 9-7
EB 7-7, 7-9
EB Scripts 3-44, 5-2, 6-23
ECAT 3-17, 3-23, 3-24, 6-7, 8-2
E-Cat Withdrawal Rate 9-20
Enable Macros button 2-1
Enriched Air 3-30
Enriched O2 3-29
Enter API 3-12
Enter C4 3-13
Enter Catalyst Information 6-19
Enter Feed Metals 6-5
Enter MAT 3-14
Entering Property Information 6-21
Enth M Btu/lbmol 8-7
EO 7-1, 7-3
Equation Oriented 3-14
Equation-oriented 7-1
Equation-Oriented Modeling 7-1
ERROR 8-5
Error Recovery 8-2, 8-3
Parameterization 8-2
Simulation 8-3
Errors 8-9
Licensing 8-9
Estimate 3-16, 3-34, 6-5, 6-21
RI 6-5, 6-21
Selecting 3-17, 3-34
ESTIMATE_DELTAP 7-2
Estimated RI 6-7
Ethylene 9-5
Evaluate 7-7
Excel 2-1, 2-2, 3-2, 3-5, 3-6, 5-14,
6-7, 6-15
Manual Accessing Command
Line 3-2
Excel 97 6-20
Excel File 3-5
Excel File menu 3-4
Excel GUI 3-6, 6-19, 7-6, 7-7
Aspen FCC 6-18, 6-19
Excel Interface 2-2
Excel menu bar 2-2, 3-3, 3-5, 3-7,
3-17, 3-43
AspenFCC 3-3
Excel VBA 3-14
Excel window 2-2
Excluding 3-32
ZSM5 3-32
Execute 3-9
Load User Input Sheet 3-8
Save User Input Sheet 3-8
EXECUTION ERROR WHILE
EVALUATING
RESIDUALS FOR UNIT
OPERATIONS BLOCK 8-9
Exp 9-8, 9-9
Expand 9-16
19 9-16
Expander Performance Curves 9-20
F
F 3-8, 3-16, 4-8, 6-9, 6-14, 6-15, 616, 7-1, 7-2, 7-4, 7-6, 9-2, 9-3
10 6-9
1317 6-11
Factors 3-38, 5-8, 7-11
100 7-12
LP 3-38
Factorspeed 5-2
FCC 1-1, 2-4, 3-3, 3-6, 3-8, 3-10,
3-11, 3-16, 3-23, 3-27, 3-29,
4-4, 4-5, 5-3, 5-8, 6-6, 6-7, 620, 7-5, 9-1, 9-3, 9-6, 9-7, 98, 9-10, 9-11, 9-13, 9-16, 9-18
Blocks 9-11
Connect 3-6
Entering 9-6
Modeling 9-1
Optimizing 1-1
FCC appdf file 3-5
FCC flowsheet 2-4, 3-1, 3-2, 3-6,
3-7
Connecting 3-1, 3-2
Initializing 3-5
FCC GUI 3-7
6 • Contents
Opening 3-7
FCC LCO/HCO 3-17
FCC Menu 5-2
FCC Nozzle System 9-16
FCC toolbar 2-2, 5-1, 5-8, 5-9
FCCGO 3-17
FCCU 3-24, 4-8
FCCU Model 9-1
FCCU Model Configuration 9-11
Fe 3-30, 3-31, 3-33, 6-21
Feed 3-29, 3-30, 6-21
Selecting 6-21
Feed Blend Sheet Review 6-7
Feed Blends 3-44, 5-9, 5-10, 6-7, 918
Feed Blends IO 3-44
Feed Blends Links 3-44
Feed Blends Worksheet 3-30
Feed Characterization 6-20
Feed Data 3-16, 3-34, 6-4, 6-9
Feed Gravity 6-2
Feed Input 3-16, 3-44
Feed Metals Option 5-8, 6-5
Feed Properties 3-30, 3-31, 5-8, 621
Feed Rate Basis 3-12, 5-4, 6-1
Feed rate summary 3-29
Feed Source Coke 9-9
Feed Stock 3-31
Displays Viscosity 3-30
Feed Stream Routings 3-19
Riser 3-19
Feed Stream Routings to Riser 3-19
Feed Type 3-16, 3-17, 5-8, 6-5
Feed Vaporization 6-9
Feed1 3-30
Units 3-30
FG O2 const 3-12, 5-4
File dialog 2-3, 2-4
Save User Data 2-4
File menu 2-2
File Name 3-6
FINES 3-23, 3-24
Fix DELTAP 7-2, 7-3
Fix PRES_IN 7-3
Flowmeter 7-4
Flowmeters 7-5
Flowrate 3-21, 3-33, 6-8, 6-21, 623, 7-4, 8-3
Flowrates 3-19, 7-6
Flowsheet 2-2, 3-6, 3-11
Flowsheet instantiation 3-2
Flue Gas Composition 6-4
Flue Gas O2 3-13, 5-5, 5-6
Flue Gas O2 const 3-12, 5-4
Fluidization 3-27
Aspen FCC
Following 9-8
Arrhenius-type 9-8
Form 9-16
Parameterizable 9-15
Format 3-17, 3-23, 3-43, 6-19, 6-20
Fps 9-13
Frac 6-17
Fractionated 3-35
Fractionated Grouped Yields 3-35
Fractionated products 3-29
Fractionation Control 3-12, 5-4, 6-2
Fractionation Parameterization 5-8
Product Data 5-8
Fractionator 3-21, 6-3, 9-2, 9-17
Fractionator parameterization 6-7
Freedom 7-5
Fresh Catalyst 9-20
Fresh Catalyst Makeup Rate 9-20
Fresh Feed Basic 3-13, 5-5, 6-2
Fresh Feed Concarb 3-13
Fresh Feed Conradson Carbon
Basis 5-5
Fresh feed conversion 3-29
Fresh Feed Gravity Basis 3-12, 5-4
Fresh Feed Preheat Temperature
Control 3-18
Fresh Feed Recycle Stream
Routings 3-19
Riser 3-19
Fresh+recycles 3-29
Functions 4-4
Optimize 4-4
G
Gas Plant Data 9-18
Gasoils 9-18
Gasoline 3-35
Gasoline Lump C5 9-3
GC 3-20, 6-4
GC s 3-19
GC/MS 6-20
General Guidelines 2-2
General Information 3-29
General Iteration Information 7-12
Generating 3-38, 5-15
LP Vectors 3-38, 5-15
Geometries 9-20
Given 7-7
GLC 9-1, 9-10
GSP 9-1, 9-6
GUI 6-23
GUI s 2-1
Aspen FCC 12.1 User Guide
H
H 3-12, 3-32, 9-11, 9-15
C 9-15
H Const 3-12, 5-4
LP 3-12, 5-4
H2 6-9, 9-10
H2S 6-8, 9-6, 9-10
Crack 9-6
HCKGO 3-17, 6-5
HCO 3-12, 3-18, 3-21, 3-22, 3-31,
3-34, 5-4, 5-5, 6-2, 9-7, 9-10,
9-17
Heading 3-30, 3-32, 3-41
Cases 3-40
Description 3-30, 3-32
Heat 3-29, 9-11, 9-12, 9-13
Desorption 9-11
Heat balance 3-29, 6-8
Heat Balance Tuning 6-9
Heat Capacity 9-20
Heat Losses 3-28
Heat Removal 6-4
Heavy 1-Ring Aromatics 9-3
Heavy 3-Ring Aromatics 9-3
Heavy Coker Gas Oil 3-17
Heavy Liquid Product Stream
Reactor Parameterization 3-21
Heavy Liquid Product Streams 321
Reactor Parameterization 3-21
Simplified Fractionation
Parameterization 3-21
Simplified Main Fractionation
Parameterization 3-21
Heavy Lump Types 9-1
Heavy Naphtha 3-30
Heavy Naphthenes 9-3
Heavy Product Rate Basis 3-12, 54, 6-2
Heavy resid 6-5
Hessian 7-6
HESSIANUPDATES 5-2
Hidden Worksheets 3-43
Hide 6-20
HN 3-12, 5-4, 9-19
HN/LCO 5-4
HN/LCO/HCO 3-12
HOIL 3-17
Host 3-5
HPLC 6-20
HTVGO 3-17, 6-5
HVGO 3-16
Hydrogen 9-4
Hydrotreated 6-5, 9-6
Hydro-treated Gas Oils 3-17
Hydrotreater 9-7
Hydrotreatment 6-5
I
IC5 9-5, 9-6
Ici 7-6
ID 6-19
Identification 3-5
Ignored 5-10
Simulation 5-10
In Row 6-19
Including 2-2, 3-17, 3-32, 3-34, 61, 6-20
API 3-17, 3-34
GC/MS 6-20
LP Vectors 2-2
Options 6-1
ZSM5 3-32
Increases 6-10, 6-12
11 6-10
1311 6-10
1321.6 6-12
Incremental Properties 4-2
Independent Variables 4-4, 4-5
Index 7-11
Next Iteration
Bound
Price 7-11
Index Most Violated UNSCALED
Residuals
Residual
Price
7-11
Index Worst Equation Non-Linearity
Ratios
Ratio
Deviation
13
Infeasibilities 8-5
Infeasible Solutions 8-4
Inferentials 9-4
Initial Values 3-43
Initial Vapor Entrainment 9-9
Initialize 3-6, 7-7
FCC flowsheet 3-5
Injection 9-19, 9-20
Input API 3-12, 5-4
Input Basic N 3-13, 5-5
Input C4 3-13, 5-7
Input Concarb 3-13, 5-5
Input ECAT MAT 3-14, 5-4
Input Ramsbottom 3-12, 5-4
Input RVP 3-13, 5-7
Input SG 3-12, 5-4
Input TBP 90 3-21
Input Total N 3-13, 5-5
Input vol 3-12, 5-4, 5-5
Input/output
Number 6-1
Inputs 3-22, 3-43, 9-17
Debutanizer 9-16
8 • Contents
7-
Param 3-43
Parameter 3-21
Simulation 3-44
Instrumentation 7-5
Introduction 3-10
Introduction Worksheet 3-10
Iron 6-7
Iso-butane 9-5
Iso-butene 9-6
Iso-pentane 9-5, 9-6
Iteration 7-12
Non-Linearity Report 7-13
Iteration Function Function Value
Ratio Model
Ratio 7-8, 8-4
Iteratively 7-1
J
Jacobian 3-38, 5-15, 7-6, 7-9, 7-12
Number 7-12
K
K 3-12, 5-4, 6-18, 7-6, 9-17
K Const 3-12, 5-4
LP 3-12, 5-4
K Factor 3-31
KEY OPERATING DATA 3-15,
3-24, 3-33, 6-3, 6-9
Simulate 6-9
Kg/hr 8-6
Kinetic Coke 9-8
L
Lab 6-22
Lab Data versus Estimations 6-7
Lab RI 6-7
Lagrange 7-7, 7-11
Largest Unscaled Residuals 7-11
Laydown 9-11, 9-12
Layers 9-16
Delumping 9-16
Lbmol/h 8-7
LCKGO 3-17, 6-5
LCO 3-18, 3-21, 3-31, 3-34, 3-35,
3-37, 5-5, 8-4, 9-7, 9-8, 9-10,
9-17, 9-19
Point 3-22
Leaving 3-24, 3-25, 3-42
Price 3-42
RXDIL 3-24
LICENSE
VALIDATION/CHECKOUT
FAILURE FOR ASPEN FCC
8-9
Aspen FCC
Licensing 8-9
Aspen Plus 8-9
Errors 8-9
Lift 9-12, 9-13
Lift Gas 3-16
Lift Gas Rate 9-20
Lift Steam 3-15, 3-16, 9-20
Light Coker Gas Oil 3-17
Light Ends 9-18
Light Ends Product Basis 5-4
Light Ends Product Streams 3-20
Reactor Parameterization 3-19
Light Naphtha Front-End Control
3-13, 5-7
Light Naphthenes 9-3
Light Paraffins 9-3
Light-Ends Product Rate Basis 312, 6-2
Line Search ACTIVE 7-8
Line Search Creep Mode ACTIVE
8-6
LN 9-19
Load Case Data 3-8, 8-2, 8-3
Load Case Data menu 2-4
Load FCC Flowsheet 3-5, 8-1
Load User Data 2-4, 3-8
Load User Data button 2-4
Load User Input Sheet 2-5, 3-8, 82, 8-3
Load Your Input Worksheets 2-5
Loading 2-4, 3-1
Aspen FCC 3-1
Data Files 2-4
Loading Aspen FCC flowsheet 3-5
Loading Parameter 2-5
LP 3-10, 3-12, 3-38, 3-39, 3-41, 41, 4-11, 5-1, 5-4, 5-12, 5-15,
6-5, 6-14, 6-15, 6-16, 6-23, 624, 7-2, 7-3, 9-10, 9-11
Ca Const 3-12, 5-4
Factors 3-38
Generating 3-38, 5-15
H Const 3-12, 5-4
K Const 3-12, 5-4
Model 3-38
Running 3-12
Setting 5-12
Shows 3-41
LP Vector Calculations 4-11
LP Vector Generation 5-15
LP Vector Generation Case 5-1
LP Vectors 2-2, 3-38, 3-39, 5-12,
6-14, 6-15
Including 2-2
LP Vectors Option 5-12
LP Vectors Worksheet 3-38
Aspen FCC 12.1 User Guide
LU 7-12, 8-6
LVGO 3-16
M
M Btu/lbmol 8-7
MAB 3-15
Model 3-15
Rate 3-15
Make 4-10, 7-8
Optimizer 7-8
Makeup Rate 6-17, 6-18
Manual Access 3-2
Command Line 3-2
Mass balance 3-29
Mass/moles 9-12
MASS_FLOW 7-2, 7-3, 7-4
MASS_FLOW^2 7-1, 7-3, 7-4
MAT 3-23, 3-33, 3-36, 5-7, 6-7, 617, 6-18, 9-1
Decreasing 6-18
Displays 3-32, 3-33
Rate 6-17
Match 3-35
C4 s 3-35
Material Balance 6-8
Material Balance Reconciliation 910
Matrix Surface 3-33
Displays 3-32
Max 5-13
Maxiter 5-2, 5-3, 7-6, 7-8
MBD 9-17
Mean Particle Diameter 9-20
Meas 3-14, 3-15, 4-8, 7-4, 7-5
Numbers 7-4
PRES_OUT 7-4
Measurements 7-4
Mechanical Data 3-24, 5-8
Metals 6-5, 6-6, 6-7
Metals Coke 9-2, 9-3, 9-9
Metals.A 6-5
Methane 9-2, 9-5
MF 9-14
MHz Pentium III PC 3-6
Microsoft Excel 3-3
Midriser 8-3
Min 4-5, 5-13
Minimize f 7-6
Miniter 5-2, 5-3, 7-8
Mix 6-7
Mixed Coker Gas Oil 3-17
MM Btu/h 8-7
MMCUFT/DAY 3-20
Model 3-15, 3-16, 3-38, 7-8, 7-9, 84, 8-5, 8-9, 9-1, 9-18, 9-19
FCC 9-1, 9-18
LP 3-38
MAB 3-15
Model Is Not Solving 8-8
Model Specifications 7-2
Model-estimated RI 6-7
Compare 6-7
Modern FCC 9-14
Modes 7-3
Mol feed/hr/vol 9-8, 9-9
Multi-Mode Specifications 7-3
Multiple Cases 5-11
Running 5-11
MXCKGO 3-17, 6-5
My Computer icon 3-5
Right-click 3-6
N
N 9-11
N/A 9-3
N2 9-13
Na 3-30, 3-31, 3-33
NAPHTHA 3-17
Naphthenes 3-30, 3-32
NBP Range 9-3
N-Butane 9-5
N-butylbenzene 9-3
Network Identification 3-5
Network Neighborhood icon 3-5
New Catalysts 6-18
Next 5-9, 5-10
Next Iteration
Bound
Price 7-11
Index 7-11
Nh 9-3, 9-8
Ni 3-30, 3-31, 3-33, 6-21, 9-2, 9-20
Nitrogen 9-19
Nl 9-8
No Creep button 3-2
NO FEASIBLE SOLUTION 8-4,
8-5
Nonlinearity Ratio 7-8, 7-12, 7-13
Non-Linearity Report 7-12
Iteration 7-13
NORMAL 7-10
Not Converged 7-6
NOT FOUND 3-17
Notes on Variable Bounding 8-8
N-Pentane 9-5
Number 7-2, 7-4, 7-5, 7-8, 7-12, 91, 9-2
Degrees-of-freedom 7-2
DOF 7-4
input/output 6-1
Jacobian 7-12
10 • Contents
MEAS 7-4
OPTIM 7-5
Reactant/product 9-1
SQP 7-8
NUMERICALLY SINGULAR 8-6
O
O 9-11
O2 3-33, 5-5, 5-6, 5-7, 6-2, 6-4, 914
Entering 3-33
Setting 6-4
Value 6-4
O2 inj 3-13, 5-5, 5-6, 5-7
O2 inj const 3-12, 5-4
O2 inj vol 3-12, 5-4
Obj/x 7-11
Objcvg 5-3, 7-6, 7-8
Setting 7-8
Objective 7-12
Objective Convergence Function 514, 7-8
Objective Function 3-41, 4-6, 4-7,
4-8, 5-1, 7-11, 7-12
Objective Function Dialog Box 4-5
Add Variables 4-5
Objective Function Value 7-8
Occluded Coke 9-9
Offgas 3-16
Offline 9-1
OK button 6-19
One-dimensional 7-6
Perform 7-6, 7-7
Online 9-4
Opening 2-1, 3-2, 3-5, 3-6, 6-12, 619, 6-23
Aspen FCC GUI 2-1
Command Line window 3-2, 623
FCC GUI 3-6
Setup Case Study dialog 6-12
Unhide dialog 6-19
Operate 8-7
10 8-6, 8-7
Operating Data 3-15, 3-33, 5-8
Opt 4-8
Opt Select 4-8
Optim 4-8, 7-5
Number 7-5
Optimization 3-25, 3-41, 3-42, 343, 4-4, 4-8, 4-9, 4-10, 4-11,
5-13, 5-14, 7-5, 7-6, 9-10
Solving 5-14
Optimization Case 5-1, 5-13
Running 5-13
Aspen FCC
Solving 5-13
Optimization Command 4-8
Optimization Timing Statistics
Time
Percent 7-8, 8-5
Optimization Variables 4-8, 4-9
Optimize Sheet 4-8
Optimize Worksheet 3-41
Optimizer 4-5, 7-8
Makes 7-8
Optimizing 1-1, 3-41, 4-1, 4-4, 4-8,
5-13, 5-14, 7-3
Activate 4-9
FCC 1-1
Functions 4-4
Return 5-13
Selecting 5-13
Using 3-41
Option Sheet Options 3-12
Option Title 5-4
Options 3-10, 3-11, 3-12, 3-13, 314, 3-16, 3-21, 3-33, 3-36, 41, 4-2, 5-4, 5-8, 5-10
Checking 3-14
Options Worksheet 3-10
Order 8-6
10 8-6
Orsat 9-15
Overall 7-8
Overall Plant Material Balance 919
Tuning Runs 9-19
Overcracking 3-28
Adjusting 3-28
Over-specification 7-3
P
P 6-3
Param 2-2, 3-8, 3-10, 3-11, 3-12, 314, 3-24, 3-44, 4-1, 4-2, 5-9,
5-10, 5-14, 6-3, 6-4, 6-5, 610, 6-12, 7-3, 7-4, 8-2, 9-10
Inputs 3-43
Refreshing 3-10, 3-11
Running 3-11, 3-14, 5-9, 8-2
Param IO 3-44
Param Links 3-44
Param Sheet 3-16, 3-18, 3-19, 320, 3-21, 3-22, 3-24, 3-27, 328, 3-29
Param Sheet Input 6-3, 6-4, 6-7
Param UserInput 3-44
Param Worksheet 3-14
Parameter 2-2, 2-5, 3-8, 3-14, 3-22,
3-25, 4-1, 4-2, 5-4, 5-5, 5-6,
5-7, 5-9, 5-10, 6-1, 6-2, 6-3,
Aspen FCC 12.1 User Guide
6-4, 6-5, 6-6, 6-7, 6-8, 6-10,
6-12, 6-18, 7-4, 8-2, 8-3, 8-8,
9-8, 9-9, 9-17
Inputs 3-21
Running 3-25
solved 5-10
Parameter Cases 5-8, 5-9
Running 5-9
Parameter Options on Options
Worksheet 6-1
Parameterizable 9-16
Form 9-15
Parameterization 3-13, 3-14, 3-43,
5-3, 5-4, 5-10, 6-7, 8-2, 9-2,
9-5
Error Recovery 8-2
Running 5-4
Parameterization Case 5-1, 5-3
Running 5-3
Parameterized 5-10, 6-13, 9-14
Parameterized Aspen FCC 5-3, 510
Partial Combustion 3-13, 5-6
Passivation 6-9
Pentenes 9-5
Perform 7-6, 9-13
DP 9-13
One-dimensional 7-7
Ph 9-3, 9-8
PIMS 3-38
PIMS Table Worksheet 3-40
PIMS Vectors Worksheet 3-40
Pivotsearch 5-3
Pl 9-3
Plant.ebs 6-23
Plex 7-9, 8-5
Updating 7-8, 8-4
Point 3-21
LCO 3-22
PONA 3-22
Positions 9-20
Pour Point 9-19
Ppm/wt 6-21
PPMW 3-31
Preconfigured 6-18, 7-5
Preheat Temperature Control 5-8
PRES_IN 7-1, 7-2, 7-3, 7-4
PRES_OUT 7-1, 7-2, 7-3, 7-4, 7-5
MEAS 7-4
PRES_OUT spec 7-5
PRES_PARAM 7-1, 7-2, 7-3, 7-4
Pressure Balance 6-4
Pressure Balance Control 5-7, 6-3
Pressure Drop Model Example 7-1
Pressure Profile 9-19
Price 3-42, 4-2
Problem 3-5
Problemi 3-2
Prod C9H20_1
mf 8-6
Prod enth M Btu/lbmol 8-7
Produces 9-16, 9-17
19 9-16
Product Data 5-8
Fractionation Parameterization
5-8
Reactor Parameterization 5-8
Product Gravity 6-2
Product Gravity Basis 3-12, 5-4
Product Rates 3-37, 3-38
PRODUCT RATES AND
PROPERTIES 3-37
Profit 2-2, 3-43, 4-1, 4-5, 4-6, 4-8,
4-10
Profit Report Worksheets 3-43
Profit Worksheets 3-42
Projected Active Constraints
Shadow 7-11
Propane 9-5
Properties 3-5, 3-37, 9-18, 9-20
Propylene 9-5
Pseudo-component 3-35, 9-1
Pseudocomponents 9-7, 9-14, 9-16
Q
QP 7-8, 7-12, 8-4, 8-5, 8-6
Solve 8-4, 8-6
R
R 9-8, 9-9
R/R 9-16
R1 7-6
Ra1 9-3, 9-8
Ra2 9-3, 9-8
Ra3 9-3, 9-8
Ramsbottom 3-13, 3-17, 3-31, 5-5,
9-18
Ras 9-8
Rate 3-15, 6-9, 6-17
33 MBBL/DAY 6-10
MAB 3-15
MAT 6-17
Rate/inventory 6-17
RC 3-26
RCR 3-30
Reactant/product 9-1
Number 9-1
Reactor 9-13, 9-14
Reactor Dilute Phase Cracking 6-9
Reactor Parameterization 3-19, 321, 5-8
12 • Contents
Heavy Liquid Product Streams
3-21
Light Ends Product Streams 319
Product Data 5-8
Reactor Stripping Steam 3-15
Reactor Vessel 9-20
Reactor/Regen 3-24
Drawing 3-26
Reactor/regen Delta P 6-3
Ready 3-6, 7-6
Changing 7-6
ReceiveVars 3-44, 4-8
Recycle Stream Data 3-18
Refining Process Services 6-18
Refractive Index 6-5, 6-21
Refresh 3-11
Param 3-10, 3-11
Regen 3-15, 3-23, 3-26, 3-27, 3-29,
3-33, 6-13, 6-18, 9-7, 9-13
Equal 3-25, 3-26, 3-27
Regen Bed Temp 6-3
Regen Cat 3-26, 3-27
Regen Flue Gas Temp 6-3
Regen/reactor 3-23
Regenerator 9-14, 9-15
Regenerator air supply summary 330
Regenerator CO vol 5-4
Regenerator CO2/CO 5-6
Regenerator Control 3-13, 5-4, 6-2
Regenerator data 3-30
Regenerator Temperatures 6-3
Regenerator-reactor-wgc 3-15
Balance 3-15
Re-hiding 6-20
CST Factors Worksheet 6-20
Reid 3-22
Relative Humidity 9-19
Remaining 9-2
Resid 9-1
Re-parameterize 5-4
Reported Variables 4-2
Re-running 9-10
Aspen FCC 9-10
Rescvg 5-3, 7-6, 7-8
Setting 7-9
Reset 2-2, 8-1
Aspen Plus 2-1
Connection 8-1, 8-2
Reset ApMain 3-5, 8-1, 8-8
Reset Ea/R 6-12
Select 6-13, 6-14, 6-15, 6-16
RESID 3-17, 6-5, 6-21, 9-3
Selecting 6-5
Resid 1-Ring Aromatics 9-3
Aspen FCC
Resid 2-Ring Aromatics 9-3
Resid Aromatic Ring Substituent
Carbons 9-3
Resid Naphthenes 9-3
Residual 7-12
Residual Convergence Function 514, 7-8
Results 3-43, 6-11, 9-9
Cat/oil 6-9, 9-9
Return 3-3, 5-13, 5-14, 8-2
Excel 3-3, 5-14
Optimize 5-13
Param 8-2
Reviews 9-11
21-lump 9-11
Rg/Rx DP 3-15, 6-4
Sign 6-4
Value 6-4
RI 3-31, 3-32, 6-5, 6-21
Estimating 6-5, 6-21
Selecting 6-21
Value 3-30
Ring Aromatics 3-32
Riser 3-19, 9-11, 9-12, 9-13
Feed Stream Routings 3-19
Fresh Feed Recycle Stream
Routings 3-19
Riser / Reactor Temperatures 9-20
Riser Outlet Temperature 3-15
Riser setup in AspenFCC 3-24
Riser superficial velocities 3-30
Riser/reactor 3-30, 6-9, 9-12, 9-13,
9-20
Riser/reactor catalyst inventory 330
Riser1 3-28, 3-30
Riser2 3-28, 3-30
Rm 7-6
Rn 7-6, 9-3
RON/MON 9-19
Row 3-39, 3-41, 4-3, 6-19
Row 111 4-2
Row 15 3-43
Run 3-12, 3-14, 3-24, 3-38, 4-2, 51, 5-2, 5-3, 5-4, 5-9, 5-10, 511, 5-12, 5-13, 5-15, 6-1, 610, 6-11, 6-12, 6-23, 8-2
AspenFCC 3-14
Case Study 4-2, 5-11, 5-12
Cases 5-1, 5-2
LP 3-12, 3-38, 5-15
Multiple Cases 5-11
Optimization Case 5-13
Param 3-11, 3-12, 3-14, 5-9, 8-2
Parameter 3-24, 6-1
Parameterization Case 5-3
Aspen FCC 12.1 User Guide
Simulate 6-9, 6-21
Simulation 3-12, 5-10, 5-11
Simulation Case 5-10, 5-11
Run Case 5-2, 5-11, 5-13
Run Case button 5-1
Run Cases menu 2-2
Run Time 3-43
Run Time Intervention 8-8
RVP 3-13, 3-22, 3-35, 5-7, 9-19
RVP spec 9-17
Rx 3-27, 6-18
RX DP const 3-12, 5-4, 6-3
WG 3-13, 5-7, 6-3
RXDIL 3-24
RXRG 7-8, 7-10, 7-13, 8-9
Aspen FCC 7-9
RXRG.BLK.MAT_CAT_DEACT_
K 6-17
RXRG.BLK.MAT_EQUIL_CAT_
ZACT 6-17
RXRG.BLK.MAT_FRESH_CAT_
ZACT 6-17
RXRG.BLK.SIVCAT_CAT_DEA
CT_PARAM 6-17
RXRG.BLK.SIVCAT_FRESH_CA
T_MUP 6-17
RXRG.BLK.SIVCAT_METALS_
DEACT_BASE 6-17
RXRG.BLK.SIVCAT_TOTAL_U
NIT_INV 6-17
RXRG.BLKEQN_CUT1ANLZ_ABP625A_
_____WTPCT 7-13
RXRG.BLKEQN_CUT1ANLZ_ABP725A2
_____WTPCT 7-13
RXRG.BLKEQN_CUT3ANLZ_ABP725A1
_____WTPCT 1.32712D+01
1.22712D+01 7-13
RXRG.BLKEQN_CUT3ANLZ_ABP725A2
_____WTPCT 1.32713D+01
1.22713D+01 7-13
RXRG.BLKEQN_CUT3VF_VAPOR_SPL_
FAC_1
1.00000D+00 7-11
RXRG.BLKEQN_CUT3VF_VAPOR_SPL_
FAC_10
1.00000D+00 7-11
RXRG.BLKEQN_CUT3VF_VAPOR_SPL_
FAC_2
1.00000D+00 7-11
RXRG.BLKEQN_CUT3VF_VAPOR_SPL_
FAC_3
1.00000D+00 7-11
RXRG.BLKEQN_CUT3VF_VAPOR_SPL_
FAC_4
1.00000D+00 7-11
RXRG.BLKEQN_CUT3VF_VAPOR_SPL_
FAC_7
1.00000D+00 7-11
RXRG.BLKEQN_CUT3VF_VAPOR_SPL_
FAC_8
1.00000D+00 7-11
RXRG.BLKEQN_CUT3VF_VAPOR_SPL_
FAC_9
1.00000D+00 7-11
RXRG.BLKEQN_CXN_EQN___3
3328_X 7-11
RXRG.BLKEQN_NAPHSNL_MOLES_AB
P325A 7-13
RXRG.BLKEQN_YLDES_TBP_FOE_VA
LUE_BIAS_CAL 1.81662D+01
7-11
RX-RGN DP const 3-12, 5-4, 6-3
RXSZ_Stripping_Eff 9-9
RXSZ_VEffl_Per_Mass_Cat_In 99
S
S 3-19, 6-20, 7-12, 8-6, 9-11
S Crackability 6-5
Save As dialog 2-3
Save Case Data 2-4, 3-8, 5-10, 623, 8-8
Save Case Data menu 2-3
Save FCC Model Data 2-3
Save User Data 2-3
File dialog 2-3
Save User Data button 2-3
Save User Input Sheet 2-5, 3-8
Save Your Input Worksheets 2-5
Saving 2-3, 3-5, 3-38, 4-8
Data Files 2-3
SC 3-26
Searchmode 5-2
Sec/mole 7-11
Secs 21.28 8-5
Secs 31.10 8-5
Secs 33.82 7-9
Secs 56.46 7-9
Select Aspen FCC 6-20
Select Case Study Range dialog 511
Select Case Study Range Dialog
Box 5-11
Select Manual Startup 3-6
Select Objective Function dialog
5-13
Select Objective Function Dialog
Box 5-13
Select Parameter 6-9
Selected Product Dialog Box 4-5
Add Properties 4-5
Selecting 2-3, 2-4, 3-1, 3-2, 3-5, 36, 3-11, 3-16, 3-34, 3-38, 4-2,
4-7, 4-10, 5-8, 5-11, 5-13, 62, 6-5, 6-13, 6-16, 6-19, 6-22,
6-23
All Use TBP90 6-2
AspenFCC 2-3, 2-4, 3-1, 3-2, 338, 4-5, 5-11
Calc Feed 6-5
Case Study 5-11, 6-12, 6-13, 614, 6-15, 6-16
14 • Contents
Debutanizer 6-12
Enter Feed Metals 6-5
Estimate 3-17, 3-34, 6-21
Feeds 6-21
HTVGO 6-5
Load User Data 3-6
Max 5-13
Network Identification 3-5
Optimize 5-13
Reset Ea/R 6-12
RESID 6-5
RI 6-22
TYPE 5-8
Unitless 4-8
Selectivities 6-18
Self-documented 3-11
SendVars 3-44, 4-8
Sequential-modular 7-1
Set regen 3-23
Set Startup Options 3-6
Setting 3-20, 4-8, 4-10, 5-10, 5-12,
6-3, 6-4, 6-5, 7-6, 7-8
0.0 6-3
1.0 6-5
CO 6-4
GC s 3-19
LP 5-12
O2 6-4
objcvg 7-8
rescvg 7-8
YES 4-8
Setup Case Study dialog 6-12
Setup Case Study Dialog Box 4-2
Setup Cases 3-9, 3-38, 4-2, 4-5, 46, 4-9, 6-13
Setup Cases menu 2-2
Setup Cases Submenu 3-9
Setup Incrementals 4-7
Setup Incrementals Button 4-5
Setup LP Vectors Dialog Box 3-38
Setup Optimization Case Dialog
Box 4-8
SG 6-2
Shadow Price 7-11, 7-12
Sheets 2-2, 3-16, 3-23, 3-43, 6-19,
6-20
User Interface 2-2
SI 7-11
Sign 6-4
Rg/Rx DP 6-4
Simple Fractionation 9-17
Simplified Fractionation
Parameterization 3-21
Heavy Liquid Product Streams
3-21
Aspen FCC
Simplified Main Fractionation
Parameterization 3-21
Heavy Liquid Product Streams
3-22
Simulate 3-14, 5-8, 5-10, 6-10, 611, 6-12, 6-21, 6-23, 7-10
KEY OPERATING DATA 6-9
Simulation 2-2, 2-5, 3-8, 3-10, 311, 3-12, 3-22, 3-43, 4-1, 4-2,
5-2, 5-3, 5-10, 5-14, 6-2, 7-3,
7-5, 8-3, 8-8, 9-7
Error Recovery 8-3
Ignored 5-10
Running 3-11, 5-10
Simulation Case Command 5-2
Simulation Cases 3-40, 5-1, 5-10
Running 5-10
Simulation IO 3-44
Simulation Links 3-44
Simulation Sheet 3-34, 3-35, 3-36,
3-37, 3-38
Simulation UserInput 3-44
Simulation Worksheets 2-5, 3-33
Singularities 8-6, 8-7
Slide Valve 9-16, 9-20
Slide Valve Delta P 9-20
SM 7-1
Sodium 6-7
Solids residence times 3-30
Solved 5-9, 5-13, 7-6, 8-4
Optimization 5-13
Optimization Case 5-13
Parameter 5-9, 5-10
QP 8-4
Solver Performance 8-4
Solver Settings 5-2, 5-3, 7-8
SOLVER SETTINGS
CREEPFLAG 8-7
SOLVER SETTINGS
CREEPITER 8-7
SOLVER SETTINGS CREEPSIZE
8-7
SOLVER SETTINGS
LINESEARCH 8-8
SOLVER SETTINGS MAXITER
7-8
SOLVER SETTINGS RESCVG 78
Source Component 9-5, 9-6
Sources of coke 3-29
SOX 9-6, 9-10
Burned 9-6
SP 3-26
Spec 3-11, 3-14, 7-4, 7-5
Changes 3-10
Type 7-4, 7-5
Aspen FCC 12.1 User Guide
Spec Colors 3-11
Updating 3-11
Specific Gravity 3-12
Specifications 7-4
Changing 7-4
Specify 3-38, 3-39, 4-1, 4-2, 7-4, 75
Data 4-1
DOFs 7-5, 7-6
DP 7-4
Varied 4-2
Specifying DataSpecifying_Data 39
Spent Cat 3-26, 3-27
Split 9-5, 9-6
Split Out Components 9-6
SQP 7-6, 7-8, 7-9
Count 7-8
Number 7-8
Squares 4-4
Sum 4-4
Standard 3-35
Standard cut products 3-29
Standard Grouped Yields 3-35
Starting 2-1
Aspen FCC 2-1
Startup Aspen FCC 3-4, 3-5, 3-7,
8-1, 8-2
Startup Aspen FCC Commands 3-4
Startup Aspen FCC Options 3-4
Startup Aspen FCC submenu 2-1,
3-4
Startup Options 3-7
Startup Options dialog 3-7
Startup Options Dialog Box 3-6
Status bar 3-43
Steam Rate 9-18
Stripping 9-20
Steam/catalyst 9-10
Step 3-7
Step Fraction 7-13
Straightforward 3-22, 3-24, 6-6
Stream 9-16, 9-17
C4s 9-16
Stripper 9-20, 9-21
Stripper Performance Curve Slope
9-10
Stripper Source Coke 9-9
Stripping 9-15, 9-16
Steam Rate 9-20
Zone Model 9-15
Strm 8-7
Submenu 3-4, 3-8, 3-9, 3-13
AspenFCC 3-9
AspenFCC menu 3-8
Submenus 3-3
Submodels 9-13, 9-14
Substituent 9-2, 9-3
Substituents 9-3
Successive Quadratic Programming
7-6
Sulfur balance 3-29
Sulfur crackability 3-31
Sulfur Distribution 9-6
Sulfur/Nitrogen 9-19
Sum 4-4
Squares 4-4
Surface Area 9-20
SUS 3-17, 3-34, 6-22
Switching 6-5
Visc Option 6-5
SYN 3-17, 6-5
Syncrude 6-5
System Status Information 8-5
T
Take 5-14
DMO 5-14
TBP 3-16, 3-29, 3-32, 3-34, 6-5, 621
Displays 3-29
TBP 90 3-21, 5-4
TBP90 3-12, 5-5
Tetrahydronaphthalene 9-4
These CONST 3-15
These LP 5-12
Thiophenes 9-7
Thiophenic 6-5
Titles 3-30, 3-32
Toolbar
Update Spec Colors button 6-1
Tools 3-1, 3-2, 6-24
Total 3-30, 6-7, 6-8
Aromatics 3-31, 3-32
Basic 3-31
Ring Aromatics 3-30
TOTAL Correlation 3-31
Total feed composition 3-29
Total Nitrogen 3-13, 5-5, 6-2, 6-21
Total Unit Catalyst Inventory 9-20
TR 3-26
Trans-2-butene 9-6
Trans-2-pentene 9-6
Transfer Line 9-16
Transfer Line Lining 9-20
Transformations 9-12
Tuning 3-28, 3-29, 5-3, 5-8, 5-10
Aspen FCC 5-3, 5-10
Data 3-28, 5-8
Tuning Data 3-28, 6-9, 6-12
Twenty-One Lump Model 9-1
16 • Contents
Twenty-One-Lump Kinetics 9-1
TYPE 5-8, 5-10, 6-21, 6-22, 7-4
Changing Specs 7-4
Feed 6-21, 6-22, 6-23
Selecting 5-8
Typical Feed Properties 6-21
Adjust Fingerprints 6-21
U
UA 5-3
Under-estimated 6-4
Under-specified 7-2
Unhide 3-17, 3-23, 3-43, 6-19
CST Factors Worksheet 6-19
Unhide dialog 6-19
Unhide Dialog Box 6-19
Unhiding 6-19
CST Factors Worksheet 6-19
Unit Configuration/Type 9-20
Unitless 4-5
Units 3-30, 3-31, 3-32
Catalyst1 3-32
Feed1 3-30
Unscale 7-12
UOP characterization 3-30
Displays 3-30, 3-31, 3-32
Update Catalyst Combo Boxes 620
Update Param Sheet 3-11
Update Param Sheet Color 3-14
Update Simulation Sheet 3-11
Update Simulation Sheet Color 333
Update Spec Color button 3-11, 41, 5-8, 5-10, 6-1, 6-21
Aspen FCC toolbar 4-1, 5-10, 621
Updating 3-11, 7-6, 7-9, 8-5
Plex 7-8, 8-4
Spec Colors 3-11
UPPER 8-4
User Data File 3-5
User Interface 2-2
Sheets 2-2
User_default.var 8-2
USER3 8-9
Using 2-3
General Guidelines 2-2
V
VABP 6-5, 6-23
VABP D1160 5-8, 5-10, 6-21
Vacuum Tower Gas Oils 3-16
Aspen FCC
Value 3-31, 3-41, 4-6, 4-7, 4-8, 6-4,
6-10, 6-12, 9-9
10 3-40, 6-14
25 6-9
30 6-12
85 9-9
Debutanizer 6-12
Ea/R 6-12
O2 6-4
Rg/Rx DP 6-4
RI 3-30
Vapor residence times 3-30
Varfile 6-24
Variables 4-2, 4-3
Specifying 4-2
VB 8-1
VBA 3-3
Vectors Command 3-38
Vectors menu 3-38
VGO 3-16, 3-17, 6-5
VGO s 6-5
View 3-23
CST Factors Sheet 3-23
View These Worksheets 3-43
Visc Option 6-5
Switching 6-5
Viscosity 6-5
Viscosity @ 210 °F 6-21, 9-18
Viscosity Cst 3-31
Vol 3-13, 4-5, 5-5, 5-6, 5-7
VRISER 3-24
VRISER1 3-16, 3-24, 3-25
VRISER1 and/or VRISER2 3-25
VRISER2 3-24, 3-25
W
WABP 3-32
Biases 3-32
Well-understood 9-1
Wet Gas Compressor 3-15
Wet Gas Compressor Performance
Curves 9-20
WG 3-12, 5-4, 6-3
RX DP const 3-12, 5-4, 6-3
WG-RX 3-13, 5-7, 6-3
Aspen FCC 12.1 User Guide
Windows 2000 3-5
Windows interoperability 1-1
Windows NT 6-20
Windows Start menu 2-1
Work Process 6-19
Worksheet Name 3-44
Worst Model 7-8
X
X - |Xstep 4-5
X_Cat_deact_K 6-18
X_Cat_deact_P4 6-17
X_Cat_deact_Param 6-17
X_Equil_cat_ZACT 6-18
X_Frac_MUP 6-17
X_Fresh_Cat_ZACT 6-18
X_HTdeact_Term 6-18
X0 7-6
Xk+kdk 7-6
Xl 4-5
Xlower 4-5
Xmax 7-6
Xmax Rn 7-6
Xmin 7-6
Xmin Rn 7-6
Xu 4-5
Xupper 4-5
Y
Yields 3-35
Z
ZACT 6-18
Zeolite Surface 3-32
Zone Model 9-15
Stripping 9-15
ZSM5 3-32
Excluding 3-32
Including 3-32
ZSM-5 3-23, 3-32, 3-36
ZSM-5 Content 9-20