PFR

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

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PFR

Postby aken » 07 February 2019, 07:42

Hi. was wondering, is the Arrhenius energy, activation energy, see attachment? also lets say l am designing a PFR with no internal tubes, do l put 0 on number of tubes or 1 as in the whole diameter is one tube. in industry what is the usual material of construction of these reactors?




kind regards,

Akan
Attachments
arrhenius E.PNG
arrhenius E.PNG (7.29 KiB) Viewed 290 times
internals.PNG
internals.PNG (6.72 KiB) Viewed 290 times
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Re: PFR

Postby jasper » 07 February 2019, 12:11

Yes, the energy term is the activation energy. The number of tubes is the number of internal tubes, not the external one.

https://www.cocosimulator.org/index_help.php?page=COUS/pfr.htm
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Re: PFR

Postby aken » 07 February 2019, 22:28

what are the units of the activation energy, it does not show what units the value should be put at. Also is Arrhenius reference temperature the temperature at which the rate constant is evaluated? if yes, then the value of activation energy is always required if the PFR is to be designed at a different temperature than the reference temperature, so that k2 (rate constant 2) can be evaluated using the Arrhenius equation; l stand to be corrected. Thank you
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Re: PFR

Postby jasper » 08 February 2019, 09:09

The wizard just creates a formula for you. You can modify the formula in any way you want. By default it divides by constant R, which is in J/mol/K (https://www.cocosimulator.org/index_help.php?page=CORN/formula.htm), hence the activation energy is in J/mol/K. If a reference temperature is entered, the Arrhenius term is 1 at reference temperature.
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Re: PFR

Postby aken » 12 February 2019, 00:49

thank you. is there any way l can plot mole fraction of a component (x-axix) vs position (y- axis)? I noticed when designing an adiabatic PFR, if l do not set the wall heat transfer coefficient to 0, it does not converge. what is the physical meaning of setting it to 0, I thought Q should be set to 0 to show that there is no heat added/removed. thank you (see attachment)
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wall k.PNG
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Re: PFR

Postby jasper » 12 February 2019, 08:25

Currently you can plot component flow vs length but not component mole fraction.

Q is externally applied heat. Wall heat transfer coefficient determines heat added via the wall (see https://www.cocosimulator.org/index_help.php?page=COUS/pfr.htm).

Can you send an example of what does not converge?
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