CO2 absorption into aqueous amine blended solutions containing monoethanolamine (MEA), N,N-dimethylethanolamine (DMEA), N,N-diethylethanolamine (DEEA) and 2-amino-2-methyl-1-propanol (AMP) for post-combustion capture processes

From the CO2 mass transfer data the largest absorption rates were observed in blends containing 3 M MEA/3 M Am2 while the selection of the Am2 component had only a marginal impact on mass transfer rates. Overall, CO2 mass transfer in the fastest blends containing 3 M MEA/3 M Am2 was found to be only slightly lower than a 5 M MEA solution at similar temperatures and CO2 loadings. In terms of equilibrium behaviour a slight decrease in the absorption capacity (moles CO2/mole amine) with increasing Am2 concentration in the blends with MEA was observed while cyclic capacity followed the opposite trend. Significant increases in cyclic capacity (26-111%) were observed in all blends when compared to MEA solutions at similar temperatures and total amine concentrations. In view of the reasonable compromise between CO2 absorption rate and capacity a blend containing 3 M MEA and 3 M AMP as blend components would represent a reasonable alternative in replacement of 5 M MEA as a standalone solvent.