Hello everyone,
I'd be grateful for any advice on the design of my CO2 absorption unit within an Ammonia plant, thank you in advance for all replies.
Context:
I am using activated MDEA (aMDEA) at a concentration of 30 wt% MDEA, 3 wt% Piperazine (PZ) with the remaining solution being water, it enters the column at 32 degC. The gas stream from which CO2 is being removed enters at 35 degC and contains:
H2O = Neglibile
CH4 = 0.69%
CO = 0.2%
CO2 = 17.87%
H2 = 61.42%
N2 = 19.5%
Ar = 0.23%
Total Flowrate = 224,910 kg/hr
Much of the literature I have read suggest that both Aspen Plus and HYSYS model the reactions between CO2, MDEA and PZ poorly, as I don't have access to software such as ProMax or ProTreat I have opted to base my design off of experimental data. Using a paper which gave partial pressures and CO2 loading across a range of temperatures I have formed a model in Matlab which accounts for the high heat of reaction, it operates under the assumption that the reaction is thermodynamically rather than mass transfer controlled (literature suggests this is reasonable for a medium conc MDEA & PZ system).
5) What is the best way to approach calculating the annual amount of amine make-up required? Presumably the make-up will contain a higher % of PZ as it vaporizes more readily and will therefore carry over at a higher rate, how would I approximate the new make-up ratio? Additionally, what is the average cost for such a make-up?
Edited by AyrtonB, 21 January 2018 - 08:30 PM.