September 24, 2014
Rigorous Simulation of Heat Exchanger Networks:
®
®
PRO/II - HTRI
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Linking Third Party Software
 Heat Exchanger Network Simulation – 2014
Process Heat Transfer Modeling - Perspective
1941- 1962
Fouling Factors Established; Kern, McAdams, Tinker, Bell-Delaware
First TEMA® design methods are published to members
1962 - 1963
HTRI® Founded
Delaware Research Project issued Final Report
1967
HTRI® Publishes Stream Analysis Method (Tinker)
Programmable, electronic desktop calculators become affordable
1977 - 1981
Apple® Computer Introduces Apple® I personal computer (4K memory)
Most PC’s provide 32K chip memory allowing program design methods
1987
HTRI® releases first PC version of Shell & Tube software
1990’s
Property Generation from a stream in PRO/II® to HTRI®
HEXTRAN® makes it possible to analyze complex heat exchanger Networks
2000 - 2014
Process Simulators linked to 3rd Party Specialty software
2015 – (?)
Specialty 3rd Party Software embedded in Process simulators to permit rigorous modeling of
process equipment
3
The heat exchanger design process
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Design is based on specified process conditions, materials, fouling factors, etc.
‘As-Built’ hardware is expected to meet / exceed duty within hydraulic limits
Each service designed as a discrete unit operation – MANUAL Steps to move Data
No check of impact to the overall system through rigorous flowsheet modeling of
vendor supplied equipment – No FEEDBACK Mechanism
 Unexpected performance may result from ‘as-built’ accumulative overdesign
and variance from ‘design’ temperature / pressure profiles
Process Data
Design
Conditions
Materials of
Construction
Heat Transfer
Data Sheet
Setting Plan
Mat’l Requisition
Installation
Startup
Operation
Troubleshoot
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HTRI® (Heat Transfer Research Inc.)
 Design, Rate, and Simulate Heat Transfer Equipment
 Rigorous Heat Transfer and Pressure Drop Calculations
 Interfaces to Process Simulators, Physical Property Banks, Mechanical Design
Programs, Microsoft Excel®, etc.
 CAPE-OPEN Compliant Applications
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Simulating Heat Exchanger Networks - Linking PRO/II® to HTRI®
 PRO/II® simulates process conditions (H&MB)
 HTRI® designs and simulates (nearly) all types of heat exchangers
 HTRI® provides a variety of CAPE-OPEN compliant exchanger types
 CAPE-OPEN is an industry software standard which allows different
3rd party process/equipment modeling software to ‘talk’ to each other
 PRO/II® Implementation of HTRI
 CAPE-OPEN will interface to 7 unique HTRI® modules
 In addition, the COM Server provides a seamless interface for PRO/II® to
communicate with Xist® (Shell & Tube) and Xace® (Air Coolers)
PRO/II®
LINK
HTRI®
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COM Server (Xist® & Xace®)
CAPE-OPEN
Linking PRO/II® with HTRI®
•
Com Server Interface (Preferred)
 Full functionality of HTRI® for S&T® (Xist®) and Air Coolers (Xace®)
 Seamlessly flanges PRO/II® to HTRI®
 Improved stability, fewer issues with inconsistencies
•
CAPE-OPEN Interface
 Permits linking to other HTRI® supported Unit Operations
 May not provide 100% of the HTRI® functionality
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Simple Heat Exchanger Network
PRO/II® ~ 2-3 seconds
HTRI® embedded > 1 minute
Slightly More Complex Exchanger Systems
 Cold End Modeling using HTRI® Xpfe® via CAPE-OPEN Interface
 Rigorous Model in lieu of LNG Block H&MB
CAPE-OPEN links PRO/II® to Xpfe
®
Cold Box Simulation
 Xpfe® Simulation checks profiles, integration effectiveness
PRO/II® - HTRI® (Xpfe®) Integration (This is Significant)

Stand-alone modeling of a single unit operation
 PRO/II® links Xpfe® via CAPE-OPEN
 Xpfe® is not connected to other flowsheet elements; does not
exchange data or contribute to the main flowsheet solution
 CAPE-OPEN Unit Operations calc’s occur after flowsheet solves
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Stand-alone modeling of a Cold Box exchanger train looks promising
 Still in early stages of testing, implementation, and validation
 SIGNIFICANT time savings for engineers
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PRO/II® - HTRI® (Xpfe®) Integration (This is More Significant)

Integrated modeling
 PRO/II® links Xpfe® via CAPE-OPEN (same as stand-alone)
 Xpfe® is fully connected to other flowsheet elements
 Xpfe® Unit Operations calc’s occur as flowsheet solves

Integrated modeling of Cold Box exchanger train is challenged
 Fails to solve in some cases
 Could be operator error but robustness / stability should be
investigated by software vendors to improve
 Opportunity for SIGNIFICANT time savings for engineers
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Quick (or not so quick) DEMO
PRO/II® - HTRI ® Integration - What are the Benefits?

Energy / Margin Credits (% OPEX, CIT, other)

Process Optimization and Improved Integration of Exchanger Networks
 Species Targets (H2, other)

“U” x Surface Area (UA) = Opportunity
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Property Generation is freaky fast
 Facilitates ‘what if’ analysis
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Analysis for Fouling Modeling / Reduction
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Benefits from combination of integration / rigorous modeling
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Optimize Heat Exchanger Design in the Network
Basic design – know the parameters!
Q = UA (f) LMTD
Q
U
A
LMTD
= duty
= overall heat transfer coefficient
= surface area
= Log Mean Temperature Difference
Pressure Drop
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Inside tube heat transfer coefficient (ℎ𝑖 ) for
turbulent flow inside tube varies ~ 𝑚0.8
Δ𝑃 𝑣𝑎𝑟𝑖𝑒𝑠 ~ 𝑚2
A realistic pressure drop should be determined
at this stage to avoid re-work
Fouling predictive models may include
pressure drop as one of the mitigating
parameters; i.e. fluid shear, temperature, etc.
(𝑮𝑻𝑻𝑫 − 𝑳𝑻𝑻𝑫)
𝑳𝑴𝑻𝑫 =
𝑮𝑻𝑻𝑫
𝐥𝐧
𝑳𝑻𝑻𝑫
𝟏
U=
[
𝟏
𝒉𝒐
𝟏
𝑬𝒇
+ 𝒓𝒘 + 𝒓𝒊
𝑨𝒐
𝑨𝒊
+
𝟏 𝑨𝒐
𝒉𝒐 𝑨𝒊
]
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Benefits
 Conceptualization, FEED, Revamps, and
EPC – get it right from the start
 Rigorous modeling will lead to valuable
collaboration w/Specialists
 Accurate Heat Transfer (U), Pressure
Drop (P), and Vibration Analysis
 Benefit / Cost for margin, energy,
reliability, cost, maintenance (basis)
 Identify ‘Enhanced’ Heat Transfer
Opportunities
Benefits
 Acceptable modifications for revamp
exchangers
 Specialty Exchangers – model these
using CAPE-OPEN / HTRI Module
 Identify TEMA Type constraints when
considering possible modifications
 Start of Run, End of Run, Turndown
conditions can highlight possible pitfalls /
avoid rework in the next phase of
engineering
Benefits
 Screen for damaging flow-induced tube
vibration or acoustic resonance at higher
flowrates, different feeds, other
 Dynamic pressure impact to equipment
(rho-V2 i.e. erosion)
 Identify unacceptable temperature profiles /
temperature approaches
 Integrated reporting (All Unit Ops / H&MB)
in one place
 Thermodynamic models and data
seamlessly match up with ‘as-built’
geometry and process conditions
Where do we go from here?
Provide Feedback to the Software Vendor(s)
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Rigorous Simulation – Go Faster!
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Stability Improvements needed for complex flowsheets

Provide hidden workaround when HTRI unit operation encounters fatal error
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Simplicity for invoking HTRI® (toggle back and forth)
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Kettles / Thermosyphon (flowsheet communication, detailed piping, etc.)

Enhanced Graphing capability in Networks across multiple exchangers
Implement HEXTRAN® Functionality in PRO/II®

HTRI® Design Mode
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Heat Integration / Pinch Analysis

Monitoring (data acquisition, conditioning, reconciliation, fouling trends)
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Questions?
Thank you