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[Pinch Analysis] Multiple Pinch Points


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#1 jamy86

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Posted 11 September 2019 - 12:35 AM

Is it possible to have multiple pinch points in a process under pinch analysis. I am trying to create a pinch analysis model in Aspen Energy Analyzer. In my process, i am getting two pinch points.

 

Is it possible? If yes, then what is the significance?

 

I tried googling or finding it in old pinch analysis literature but couldnt find answer to this anywhere.

 

Any pinch analysis experts can guide me please!



#2 gegio1960

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Posted 11 September 2019 - 10:15 PM

simply decided to choose one of the points....

 

Attached File  compo961.JPG   48.64KB   2 downloads

 

Attached File  compo961_2.JPG   72.59KB   0 downloads


Edited by gegio1960, 11 September 2019 - 10:45 PM.


#3 jamy86

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Posted 17 September 2019 - 05:11 AM

So,
My process is showing pinch points as

368 / 343
and
65 / 40

Then you mean to say that i can just selwct 368 / 343 as the pinch point and ignore 65/40 point??

#4 gegio1960

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Posted 18 September 2019 - 01:59 AM

the pinch point is defined by one temperature, where the 2 (shifted) composite curves touch each other: on that you apply the DTmin

you're giving 2 couples of points, so the situation is not clear.

maybe your pinch points are at 65 and 368°C and you've applied 25°C of DTmin

in this case, in my opinion, you can identify 368°C as the pinch point of your project (a Crude Distillation Unit, I suppose).

good luck!


Edited by gegio1960, 18 September 2019 - 02:01 AM.


#5 jamy86

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Posted 15 October 2019 - 10:45 PM

UPDATE:

 

Posting late update. I checked the GCC and found the curve intersecting Y axis at 368/343 temperature. So I ignored 65/40 point and concluded the study.

 

Thanks gegio1960 for the replies!



#6 pavanayi

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Posted 25 October 2019 - 03:51 PM

You have selected the right option. The hotter pinch point is the process pinch, and I guess the colder pinch point is a utility pinch point.
For anyone else reading this, there can only be one process pinch point.

Pavanayi




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