rigorous simulation of heat exchanger networks: pro/ii -...
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Rigorous Simulation of Heat Exchanger Networks: PRO/II® - HTRI®
September 24, 2014
Linking Third Party Software Heat Exchanger Network Simulation – 2014
3
Process Heat Transfer Modeling - Perspective
1941- 1962 Fouling Factors Established; Kern, McAdams, Tinker, Bell-Delaware
First TEMA® design methods are published to members
HTRI® Founded
Delaware Research Project issued Final Report
HTRI® Publishes Stream Analysis Method (Tinker)
Programmable, electronic desktop calculators become affordable
Apple® Computer Introduces Apple® I personal computer (4K memory)
Most PC’s provide 32K chip memory allowing program design methods
HTRI® releases first PC version of Shell & Tube software
Property Generation from a stream in PRO/II® to HTRI®
HEXTRAN® makes it possible to analyze complex heat exchanger Networks
1962 - 1963
1967
1977 - 1981
1987
1990’s
2000 - 2014
2015 – (?)
Process Simulators linked to 3rd Party Specialty software
Specialty 3rd Party Software embedded in Process simulators to permit rigorous modeling of
process equipment
4
Process Data
Design Conditions
Materials of Construction
The heat exchanger design process
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
Heat Transfer Data Sheet Setting Plan
Mat’l Requisition
Installation Startup
Operation Troubleshoot
5
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
6
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® HTRI® LINK
COM Server (Xist® & Xace®)
CAPE-OPEN
9
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
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
13
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
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
14
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
Quick (or not so quick) DEMO
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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
Property Generation is freaky fast
Facilitates ‘what if’ analysis
Analysis for Fouling Modeling / Reduction
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 = duty
U = overall heat transfer coefficient
A = surface area
LMTD = Log Mean Temperature Difference
Pressure Drop Inside tube heat transfer coefficient (ℎ𝑖) for
turbulent flow inside tube varies ~ 𝑚 0.8
Δ𝑃 𝑣𝑎𝑟𝑖𝑒𝑠 ~ 𝑚 2
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.
𝑳𝑴𝑻𝑫 = (𝑮𝑻𝑻𝑫 − 𝑳𝑻𝑻𝑫)
𝐥𝐧𝑮𝑻𝑻𝑫𝑳𝑻𝑻𝑫
U = 𝟏
[𝟏
𝒉𝒐
𝟏
𝑬𝒇+ 𝒓𝒘+ 𝒓𝒊
𝑨𝒐𝑨𝒊
+ 𝟏
𝒉𝒐
𝑨𝒐𝑨𝒊
]
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
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Provide Feedback to the Software Vendor(s)
Rigorous Simulation – Go Faster!
Stability Improvements needed for complex flowsheets Provide hidden workaround when HTRI unit operation encounters fatal error
Simplicity for invoking HTRI® (toggle back and forth)
Kettles / Thermosyphon (flowsheet communication, detailed piping, etc.)
Enhanced Graphing capability in Networks across multiple exchangers
Implement HEXTRAN® Functionality in PRO/II®
HTRI® Design Mode
Heat Integration / Pinch Analysis
Monitoring (data acquisition, conditioning, reconciliation, fouling trends)
Where do we go from here?
Questions?
Thank you