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8/12/2019 summer09 Biegler design.pdf
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8/12/2019 summer09 Biegler design.pdf
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The TextbookDeals with decision-making conceptsrelated to process design
Technical and Economic Evaluation ofProcessesMaterial easily leveraged with capstonedesign project
Conceptual and Heuristic SynthesisOptimization FormulationsBackground on Mathematical
Programming
Undergrad/graduate level over multi-semester sequenceUseful research reference (widely citedin international scientific literature)
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Design Course teaches
Synthesis of engineering content and professionalpractice
Activities that mimic the real-world workplace in
process engineering Social process that leverages diverse
personalities and skills
Evolving to Products and New Processes Decision-making based on engineering
experience and domain knowledge2
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Issues for Decision-making Ill-defined problems --> well-defined formulations
Metrics to compare alternatives safety environmental impact and sustainability energy efficiency
economics
Search among a rich set of alternatives
==> Research in PSE has focused on these issues overthe past four decades
How should this be taught in a design course?
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The BasicsHow should a flowsheet be constructed?
- rule-based hierarchies, based on Rudd, Powers, Siirola andDouglas
- reflect decisions that lead to state-of-the-art continuous processes
How should a flowsheet be evaluated?
Technical Feasibility: Does it produce the desired productsfrom given feedstocks?- shortcut models and linear mass balances ==> flowsheet
interactions- evolve to detailed simulation models ==> what additional
information is gained
Economic Feasibility: Will it be profitable for the company?- capital and operating costs- time value of money- NPV vs. rates of return
- economic evaluation
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Process Simulation and ModelingTools
0.001
0.01
0.1
1
10
100
1000
1981 1985 1994 2000
Cycle time ( s)
Simulation TimeEquivalents
Overall P e r f o r m a n c e
f o r
O p
t i m
i z a
t i o n
4-6 orders of magnitude speedup in 20 years About three orders of magnitude due to solution
algorithms Essential tools for process engineering education Ubiquitous, on everyones laptop
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Optimization Impact on Process Simulation Shorter Design Cycles - 1 hr vs. up to 2 weeks of case studies to get
same design
Significantly better and more consistent performance in workprocesses
Nonintuitive results- Increased process understanding- Explore limits of process model
- Sensitivity information on process performance
Lower level decisions of process engineering handled by optimizer
Higher level decisions handled by process engineer, but can easilybe misused power tool analogy!
Understand what is under the hood
Diagnose problems and check answers
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Process Synthesis ConceptsFocus on problem definition and descriptive tools to demonstrate trade-
offs in design
Energy Integration- pinch technology- heat and power systems- capital vs. energy
Energy Targeting and HENS hot/cold minimum utilities matching rules for HEN widely effective tool easy to teach
Tmin
QH,min
QC,min
Heat content H
hot composite curve
cold composite curve
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Process Synthesis ConceptsFocus on problem definition and descriptive tools to demonstrate trade-
offs in design
Separation Synthesis- separation sequencing and complex columns- nonideal/azeotropic separation- combinatorics vs. models
Effective Sequencing Strategies
Triangular phase diagrams
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Process Synthesis ConceptsFocus on problem definition and descriptive tools to demonstrate trade-
offs in design
Reactors- beyond reactor design- networks vs. models- attainable regions
Novel Graphical Approach new insights on networks easy to teach limited by visualization 1.21.00.80.60.40.20.0
10.0
5.0
0.0
15.0
F
A
B
G
H
E
D
C A
CB
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Process Synthesis Concepts All of these can be represented and solved as
Optimization Problems
Advanced tools for evaluation of best designs, not justfeasible designs Assess the best trade-offs Deal with uncertainty in the best ways
Extend beyond graphics to more advanced cases (multipleutilities, multidimensional kinetics)
Natural way to integrate design aspects Balance economics (capital vs. operating costs vs. environment) Integrate subsystems (energy, separation, reaction)
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Optimal Flowsheets with Heat Integration
MIXER1
2
5
PROX
FCSTACK
13
14
15
COMPR1
16
FLASH
POSTCOMB
17
18
20
COMPR2
HEX7
3
HEX1
6
HEX2 HEX3
10
HEX421
HEX5
22
HEX6
23
WGS
24
SMR
HEX8 26
C 1
C 2
C 3
C 4
Cold stream C i
H 1
H 2 H
3 H 4
H 5
H 6
H 7
H 8
H 9
Hot stream H i
C 1
C 2
C 3
C 4
Cold stream C i
H 1
H 2 H
3 H 4
H 5
H 6
H 7
H 8
H 9
Hot stream H i
Optimal trade-off: operating cost, capital, revenue for best heat integrateddesignCannot be obtained with insights and graphical methods
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13
Teaching Optimization in Design?
First Semester
Problem Representation, Graphical Insights
Alternative Generation for Flowsheets and ProcessSimulation
Metrics for Evaluation Economics
Second Semester
Optimization formulations and solutions
- GAMS, Aspen/Plus, ExcelCapstone Design Project
- Real-world team projects using advanced tools
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The FutureSystematic decision-making extends to:
Further integration of multiple objectives, subsystems
and modeling platforms
New processes: energy, bio- and nano- systems Development of models and need for decision-making
Multi-scale modeling and simulation: Ab Initio, Molecular Dynamics, CFD, Process simulation,
Planning, Scheduling Leveraging large-scale decision-making: knowledge of
optimization tools and problem formulations