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Reaction stoichiometry calculation issue

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I'm trying to model an ammonia decomposition reactor, in which my overall reaction is

NH3 <-> (3/2)H2 + (1/2)N2

Yet, my model seems to have two issues at the moment:

1) The number of moles in my output upon nearly complete conversion is not twice my input (as dictated by the stoichiometry - see Derived Values: line integrals in solution)

2) The ratio of H2/N2 in the output is not 3/1 (again, as stoichiometry suggests - see Mole Fraction plots in solution)

I assume it is some peculiar input method I have done incorrectly, so I was hoping someone with experience might be able to tell me what's gone wrong.

This model uses v5.3 and has the Chemical Engineering Module. I am specifically using the Free and Porous Media Flow + Heat Transfer in Porous Media + Transport of Concentrated Species.

Also, I tried using two types of reaction terms in the Transport of Concentrated Species (Reaction and Reaction Source) but both give similar results.

Can anyone provide feedback on possible causes for these discrepancies? I appreciate any time and effort you may provide. Thanks.


0 Replies Last Post Jun 16, 2017, 2:56 p.m. EDT
COMSOL Moderator

Hello Sean Lundin

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