3 replies to this topic

[Muneeb]

Greetings! what I require are the joule thomson coefficients for the following compounds:

Cumene(isopropylbenzene)
1,4 diisopropylbenzene

and please don't suggest the nist.gov site because these compunds are not available there...

Thanking in anticipation

[Muneeb]

I should have been more explanatory to my request...actually there's is a throttling process occuring in a phase separator that needs to be designed for my thesis..the inlet is benzene,propane,propene,cumene, and di-isopropylbenzene...at conditions of 31 bar & T=119 degrees C...what happens is that propane and propene are removed form the top as gases while the bottom is benzene, cumene and di-isopropylbenzene in liquid form at conditions of T=119 degrees C and P=3.75 bar...now i believe that there will be cooling in the unit due to pressure reduction and what i wantto do is find out that temperature at the outlet after this cooling...so i need help in that..i do not however believe that joule thomson coefficients are necessary for determining that temperature...

Considering the above explanation I would really be thankful if someone can guide me as to how i can calculate that temperature...

[Art Montemayor]

Yes, you are absolutely correct. You should have been specific in your request - as you also have failed to do now, as well.

Please be specific in your thinking out how you should express yourself and your problem. You have now correctly described that you really have a separator and that you are removing gas from the top and liquids from the bottom.

But what you fail to tell us is that the process is continuous and that the FEED to the separator is being adiabatically expanded into the separator while you maintain the separator pressure constant by removing the gas formed by the expansion. Is that what is REALLY HAPPENING HERE? If so, then please tell us or concur with what I wrote. If not, then tell us what the process is all about -- just as I have tried to explain it (without knowing a thing about your process).

If you are preparing a thesis, surely you know by now how to explain your own process in a clear, accurate, and succinct manner. An accurate and well-drawn schematic drawing would also help. I don't know about other members, but I will put as much effort in the solution as you put into the presentation of your problem.

Await your reply.

[mbeychok]

Muneeb, I agree with Art Montemayer that you have not explained your problem well enough.

Assuming that the feed to your separator is a liquid, it sounds to me that what you have is a flash evaporation of a multi-component liquid mixture. If I am correct, you will need to use the Rachford-Rice Equation (or some equivalent multi-component flash evaporation equation). For more information, read this article in the Citizendium online encylcopedia:

Flash evaporation