Kinetics of CO2 absorption in aqueous ammonia solution

The kinetics of CO2 absorption in unloaded aqueous ammonia solution were measured using a string of discs contactor with the aqueous ammonia concentrations ranging 0.9–5.4 kmol/m3 and temperatures ranging 298.3–321.9 K. The reaction rates strongly increase with the concentration and less strongly with temperature. Both the termolecular and zwitterion models were applied in this study as amine solutions. The parameters for both of the models were interpreted. The kinetic rate constants for CO2 absorption in aqueous ammonia were compared with those for other amines and were found to be around 1/10 that for monoethanolamine. The fitting results for the termolecular mechanism seem more robust than those for the zwitterion mechanism from a statistical perspective.