Modeling VLE of fatty acids in Aspen Plus

[TobiasDS]

Hello,

I need to simulate a distillation column for the seperation of fatty acids at 5-15 mbar in Aspen Plus. The simulation of the column is no problem for me, but with selecting the right model and specify it, I got some problems.
For the moment I'm looking to the NRTL and UNIQUAC models, coupled with Nothnaghel or Hayden-O'Connell (this coupling for association in the vapor phase). The boiling points of the pure components and the liquid phase (with Hayden-O'Connell) are described well, but not the vapor phase.

Can someone help me and say what I need to do? I guess that the source of my problems is places under the Properties envoriment, Methods/Selected Methods/...

Thank u verry much

 

[georgeverghese]

Interesting. If this is of any use to you, there is some discussion on the modelling for dimerisation in the vapor phase in Perry Chem Engg Handbook, 7th edn on page 13-20 (section on Distillation) - see also equation 13-5 to 13-9 for extracting liquid phase activity coeff with the dimerisation constant correction.

 

[TobiasDS]

Thank you a lot.
I will take a look at it.