FixedConversionReactor issue

Discusses use of COCO, the process simulation and modelling software suite from AmsterCHEM, downloadable from http://www.cocosimulator.org

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FixedConversionReactor issue

Postby rodolfo » 08 July 2014, 17:56

Hello,

I'm trying to produce Example 1 of Perkins (1979) (DOI: 10.1016/0098-1354(79)80059-9). This example uses 2 fixed conversion reactors but COCO doesn't convert anything.
I cannot figure out what is wrong with them. The attached file includes one of them.

Feed stream:
80 mol/h of C2H6, 120 mol/h of C3H8,
620ºR, 500 psi

Reaction:
3C2H6 + 6C3H8 --> 4H2 + 4CH4 + 5C2H4 + 2C3H6 + C4H10
90% conversion of C3H8

Regards,
Rodolfo
Attachments
Perkins1979-Example1-FixedConversionReactor.fsd
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Re: FixedConversionReactor issue

Postby jasper » 08 July 2014, 20:00

You have specified a conversion of 90% of the entering ethylene, but zero ethylene enters, so zero reaction takes place.... Did you mean to specify the ethane conversion?
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Re: FixedConversionReactor issue

Postby jasper » 08 July 2014, 20:01

Your mail suggest that you wanted to convert 90% of the propane. Change the ethylene conversion to propane conversion, and you will get

Stream 2 unit
Overall pressure 500 psi
Overall temperature 620.00001 °R
Overall mole fraction [Ethane] 0.079754601
Overall mole fraction [Propane] 0.036809816
Overall mole fraction [Hydrogen] 0.2208589
Overall mole fraction [Methane] 0.2208589
Overall mole fraction [Ethylene] 0.27607362
Overall mole fraction [Propylene] 0.11042945
Overall mole fraction [N-butane] 0.055214724
Overall flow 326 mol / h
Overall MW 0.023610941 kg / mol
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Re: FixedConversionReactor issue

Postby rodolfo » 09 July 2014, 20:05

Thanks, Jasper.

I had revised every specification but I forgot to check the compound specification of reactor.
I just realized that fixed conversion reactor sorts the compounds in alphabetical order:

Image

It is different of order I inserted those compounds in to simulation:

Image

The second compound of fixed conversion reactor (ethylene) is not same of second compound of feed stream (propane).

Thanks again.
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Re: FixedConversionReactor issue

Postby jasper » 10 July 2014, 06:29

Glad to hear it works.
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