Absorber intercooling in CO2 absorption by piperazine-promoted potassium carbonate



Intercooling was evaluated as a process option in CO2 absorption by piperazine (PZ) promoted potassium carbonate. The system performance with 4.5 m K+/4.5 m PZ was simulated by a model in Aspen Plus® RateSep™. The absorber was evaluated for use with a double matrix stripper by optimizing the position of the semilean feed and intercooling stages to maximize CO2 removal. Additionally, a simple absorber system was modeled to observe the effect of intercooling on systems with variable CO2 lean loading. Intercooling increases CO2 removal by as much as 10% with the double matrix configuration. With a simple absorber, the effectiveness of intercooling depends on solvent rate. Near a critical liquid/gas ratio (L/G) there is a large improvement with intercooling. This is related to the position of the temperature bulge. An approximation is proposed to estimate the critical L/G where intercooling may maximize removal. © 2009 American Institute of Chemical Engineers AIChE J, 2010