Chapter 19 performance problems

Chapter 19 Process Input/Output Models

Department of Chemical Engineering

West Virginia University

Copyright R. Turton and J. Shaeiwitz 2012 1

Chemical Process or Unit

Copyright R. Turton and J. Shaeiwitz 2012

process input output

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known

unknown the design problem

Inputs feed recycle utilities work heat bfw

Outputs products recycle steam condensate cw return work heat

Process equipment

3




known

unknown the performance problem

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troubleshooting problem: Unanticipated change in output observed. What is cause? It must be a problem with the input or the process.

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debottlenecking problem: Want to make change in output. What parts of process and/or input limit ability to modify input?

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Problem Solving Strategy – 1

• Fogler and LeBlanc

– Define

– Generate

– Decide

– Implement

– Evaluate

• Woods

– Define

– Explore

– Plan

– Do it

– Look back


Problem Solving Strategy – 2

• Define – make sure you are solving correct problem

• Generate – brainstorming works

• Decide – narrow down ideas

• Implement – solve problem

• Evaluate – review results: Do they make sense? What needs to be modified?


Suggestions – 1

• Do not get married to one idea – explore alternatives

• Input can not be assumed in any performance problem

• Must use all relationships for unit

• Not sufficient to say that unit is oversized, so it will work


Suggestions – 2

• Problem in one part of process may be caused by upset in very different part of process

• Must analyze each unit individually


Summary

• Design vs. performance problems

• Troubleshooting

• Debottlenecking

• Problem-solving strategies
