Effect of adding ammonia to amine solutions for CO2 capture and mass transfer performance: AMP-NH3 and MDEA-NH3

The overall mass transfer coefficients of aqueous 2-amino-2-methyl-l-propanol (AMP) + NH3 and N-methyldiethanolamine (MDEA) + NH3 solutions with carbon dioxide (CO2) were determined by measuring their absorption rates. The CO2 absorption characteristics of an NH3 solution added to AMP and MDEA were investigated using a wetted wall column and a packed column. The absorption performance in the packed column was investigated using structured packings and Raschig rings. NH3 addition significantly increased the mass transfer performance of AMP and MDEA solutions. Additionally, the absorption rate of each solution increased as CO2 partial pressure increased. The absorption rate of CO2 in the AMP/NH3 solution was higher than that in the aqueous MDEA/NH3 solution. The rate of increase in overall mass transfer coefficient (KGav) by using structured packings with the addition of NH3 was higher than the rate of increase in KGav by using Raschig rings. These results show that using NH3 additive and structured packings yields an effective overall mass transfer coefficient.