Promoted CO 2 absorption in aqueous ammonia

Aqueous ammonia is a promising solvent for post combustion CO 2 capture but the CO 2 absorption rate in aqueous ammonia alone is low. This short communication investigates the effect of seven additives as potential promoters of CO 2 absorption in aqueous ammonia, and aims to inspire more research to develop effective promoters to increase CO 2 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 °C using 3 M (mol/L) NH 3 in the presence and absence of 0. 3 M of each additive. CO 2 mass transfer coefficients increased to different extents in the presence of different additives. Piperazine, 1‐methyl piperazine and sarcosine sodium salt promoted CO 2 absorption in aqueous NH 3 to a greater extent than the other additives. © 2012 Society of Chemical Industry and John Wiley & Sons, Ltd