High Pressure Ammonia Absorber Simulation

[Said92441322]

Hello All,
I want to simulate An ammonia absorber same as the attached sketch.The purpose of the simulation is to see the effect of increasing ammonia concentration in the solvent stream on the top product stream ammonia concentration. Could you please advise me what fluid package I should use in oreder to get more reliable results??

 

[georgeverghese]

The Simsci - Pro II applications reference manual indicates this can be done with the NRTL package - the application shown in this manual is for acetone - water - ammonia, so this should be even easier with your components.
The other problem you've got is to convert the 20 real trays to equilibrium trays or theoretical trays - there are examples for this translation in the Gas Absorption chapters in Perry Chem Engg Handbook.

 

[apetri]

at high pressures an option could be NRTL plus a EOS such as Peng Robinson (with complex mixing rules as Huron Vidal, Wong Sandler etc.)
Solving separations I set the same model for both VLE and Enthalpy (for example, Peng-Robinson + NRTL with Huron Vidal mixing rules, PRX-NHV in Prode) , but I don't know if that is possible with your software.

 

[Said92441322]

Dear Apetri,
Well I will be using aspen hysys software for the simulation.

 

[apetri]

if I remember correctly Huron Vidal mixing rules should be available in Aspen with MHV prefix, while Wong Sandler mixing rules should be WS (see the manual for the details).

 

[georgeverghese]

Cautionary note on the ref application in Pro II - this runs at some 12barg, while your column runs at a pressure where there may non idealities in the fugacities, but since the major components here are non polar - light H2 and N2, the effect of this high pressure may be only slight (?).