The contribution of l-Arginine to the mass transfer performance of CO2 absorption by an aqueous solution of methyl diethanolamine in a microreactor

Abstract

The current study investigates the effect of adding l-arginine as a potential promoter for the conventional methyl diethanolamine (MDEA) in the carbon dioxide (CO2) capture process in a T-junction microreactor. The overall gas-phase mass transfer coefficient (KGaV) and CO2 absorption efficiency (ef) were evaluated under distinct operating conditions, including total amine + amino acid concentration of 50 wt%, the liquid flow rate of 3–9 mL min−1, and gas flow rate of 120–300 mL min−1. The composition of different concentrations in the mixture were as MDEA (50%), MDEA + ARG (46 + 4%), MDEA + ARG (42 + 8%),MDEA + ARG (38 + 12%). The impact of amino acid concentration on the physical properties of the aqueous MDEA solution was also compared in four solutions. The results indicated that increasing the arginine concentration from 4 wt% to 12 wt% intensifies the ef values from 78.91 to 92.7%, while the solution density and viscosity grows slightly. Furthermore, the values of the KGaV in the CO2 absorption enhanced from 14.34 kmol/(m3 kPa h) in aqueous MDEA (50%) solution to 63 kmol/(m3 kPa h) in MDEA + ARG (38 + 12%). It confirmed that arginine could apply as a potential chemical activator in the mixture of MDEA-ARG to intensify the absorption of CO2 in the post-combustion CO2 capture processes.