Simple question regarding Vapor-liquid equilibria in HYSYS

[JohnnyABV]

Hi

I am evaluating experimental data for vapor liquid equilibria in HYSYS, and have a simple question regarding the procedure:

Let's say I have 0,5 mol of a CO2 and 0,5 mol of methanol. To evaluate the amount of CO2 dissolved in methanol, what calculation is correct?

0,5 mol CO2 and 0,5 mol methanol in mixture, 6,167 bar, 233,15 K: Experimental data of CO2 in liquid : 0,28.

Simulation: Gas phase: 0,3332 mol; 0,9997 mol% CO2, 0,0003 mol % methanol
Liquid phase: 0,6668 mol; 0,2503 mol% CO2, 0,7497 mol% methanol

calculation: alt1: The answer is 0,2503 mol% CO2
alt2: the answer is: (0,2503) * 0,6668 mol = 0,17 ; (0,17 mol CO2 in liquid / 0,5 mol CO2 in total) = 0,334 mol % CO2

Thank you for your time

 

[LeoChem]

If the question is how much CO2 is dissolved in methanol, the answer should be:

1) 0,17 mol of CO2/0,5(0,4999) mol of methanol

This would be the answer with no need to complete the division operation

The 0,2503 is more like mol% of CO2 in teh liquid solution. believe there's nothing to do with what you are looking for.

About the difference to the experimental data, you should check the data you entered first and then try to change the model you are using to solve your equilibria equation. Is the one you use to find the activity coeficients GamaCO2;PhiCO2 and GamaMethanol;PhiMethanol for the liquid/vapor equilibria (the most famous are UNIFAC, UNIQUAC and WILSON).

Hope I could help