3 replies to this topic

[kripat-96]

Hi there, I have a multicomponent feed into a flash distillation unit operation, and to calculate the compositions out of the flash drum, I need to determine the K-values (K=y/x) of every component in the feed.
The components of C1, C2, C3, iC4, nC4, iC5, nC5, C6, C7+, CO2, N2 and H2S were all determined by data from the GPSA charts.
However for the components of mercaptans, carbon disulphide, carbonyl sulfide and water, I am unsure how to calculate the K-values.
I understand that due to a flash pressure of 22 bar(a), Raoult's Law is invalid and an alternate approach is to calculate K=(psi_L/psi_V) however I am unsure how to determine the fugacity coefficients via Equations of State methods.

The only data available is the flash pressure 22 bar(a), flash temperature; 300K and the compositions of the components as liquid in the feed.

Edited by kripat-96, 12 February 2016 - 01:59 AM.

[MrShorty]

Quote

however I am unsure how to determine the fugacity coefficients via Equations of State methods.

Computation of VLE can be a significant portion of a thermodynamics of VLE course. I don't think it is practical to try to recreate such a course here.

 

My first recommendation would be to review your desired thermodynamics of VLE course textbook or equivalent (this online course looks interesting https://www.e-educat...png520/m17.html). If you have difficulty implementing a specific part of the algorithms described by your chosen text, bring those questions back here and we can see if we can help you with more specific questions.

[srfish]

One way is to calculate the pseudocritical propeties of those components that you mentioned that you were unsure about. This can be done by the method of Lee-Kesler. Their method can be found in several physical property books. Water is a special case. There has been some work done on this by I believe it is Campbell.

[breizh]

http://www.questcons...dew_points.html

 

Hi ,

On top of what have been explained above , you may find interesting  this resource to support your work.

 

Good luck.

 

Breizh