Promoted CO2 absorption in aqueous ammonia

Aqueous ammonia is a promising solvent for post combustion CO2 capture but the CO2 absorption rate in aqueous ammonia alone is low. This short communication investigates the effect of seven additives as potential promoters of CO2 absorption in aqueous ammonia, and aims to inspire more research to develop effective promoters to increase CO2 absorption in aqueous ammonia and further advance the aqueous ammonia-based capture process. The additives were monoethanolamine, piperazine, 1-methyl piperazine, 4-amino piperidine and the sodium salts of three amino acids: sarcosine, taurine and glycine. Experiments were performed on a wetted wall column at an absorption temperature of 15 degrees C using 3 M (mol/L) NH3 in the presence and absence of 0. 3 M of each additive. CO2 mass transfer coefficients increased to different extents in the presence of different additives. Piperazine, 1-methyl piperazine and sarcosine sodium salt promoted CO2 absorption in aqueous NH3 to a greater extent than the other additives. (c) 2012 Society of Chemical Industry and John Wiley & Sons, Ltd