summer09 biegler design.pdf

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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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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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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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

summer09 biegler design.pdf

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