CO2 Absorption from flue gas HYSYS 2

[ChantalBaz]

I´m having problems with my simulation in HYSYS. I'm simulating CO2 absorption from flue gas with MEA 30%w, my problem is the stripping section. I only specifying in the stripper the reflux ratio =0.3, temperature in the reboiler=120 °C, pressures around 180 psi, and stages=20. I found in different sources that typically reflux ratio is 0.1 to 0.3 but with this ratio I have high temperatures in the condenser and the stream that suppose to be CO2, it's 80% mol water. Another doubt is that in some articles, I read that the condenser is partial and I'm specifying reflux total. The diameter in my tower is the default value, I don't know if this is a problem too.

Please help me!

 

[xeng]

for these applications I prefer Promax

http://www.bre.com/ProMax-Main.aspx

BRE people provides all the required technical assistance (if you post here I must suppose that Aspen is not helping)
For a real application (not a student work) technical assistance and support has a value.

 

[georgeverghese]

Yes, this condensor is a partial condensor. Pressure at 180psi is way too high, should be much lower - that may explain why this stripper cannot spring the CO2 out of the MEA.

 

[ChantalBaz]

I also read that a higher pressure in the stripper benefits to the requirement of the steam in the reboiler, Can you told something about that??
please

 

[georgeverghese]

Many stripper operations have a significant gas phase solute partial pressure dependance, so at high pressure, product lean solvent CO2 loading will be higher for a fixed reboiler temp. To counter that, more steam will be required to raise the reboiler temp to bring stripper exit lean solvent CO2 loading down again.

 

[mpetier]

ChantalBaz,
the selection of partial or total condenser can depend from presence (or not) of incondensables (as for other separations),
it may seem that you have not experience with these simulations, if that is the case better to ask for specific technical assistance as suggested by xeng,
(note that students are not allowed to post in this forum)

 

[ChantalBaz]

I am wrong in the units I specified before, the stripper it's operating at 180 kPa, sorry for the misunderstanding.
FYI, I'm actually working in and Oil & Gas Company but I don't have the expertise in this item. Thank you for your advice.