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[msu-htruong]

Hello! I am having trouble with trying to solve for my molar flowrates with just using the Atomic Species Balance method. I have posted my problem as well as all my work for this problem. I know that I can solve using extent of reactions which I already know how to do. However, I want to do it using the ASB.

 

For the reaction CO+ 2H₂​ ----> CH_​3​OH the production of methanol. My problem here is that the atomic species C and O occur in the same ratio where ever they appear in a process--from my textbook-- balances on those species will not be independent equations. I was able to solve for n₃ and n₄​ but I got stuck once I moved on due to the fact that I have more unknowns than I have equations.

Please help! I really want to try and do this without using the Molecular Species Balance. Thank you very much!

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[Francisco Angel]

Dear msu-htruong:

I think you are losing information, by example in the hydrogen balance at condenser:

 

350*.6303*2+350*.0948*4=n5*4+(0.996-x)*n6*2+0.04*n6*4

 

If you consider that hydrogen in H2 form goes to recycle only and hydrogen in CH3OH goes to product and recycle you actually have two independent equations:

 

350*.6303*2=(0.996-x)*n6*2

 

350*.0948*4=n5*4+0.04*n6*4

 

You must think how to avoid that information loss when using the "by species balance", I haven't reviewed that topic in a while so I can't help you right now.

Also you must also consider methanol at the inlet of the reactor, (remember the 0.40% mole percent in the recycle stream), it seems to me that you didn't consider it.

 

Best regards.