Gas-phase mass transfer coefficient of CO2 in different alkanolamine solutions within packed-bed absorption column

Abstract

For suppressing the global warming phenomenon, CO2 capture and storage has increasingly drawn attention from many research groups. Among various methods, absorption of CO2 using aqueous solution has been recognized as one of effective alternatives. As a result, there are many absorbents explored for improving CO2 capture and storage capability, which is limited by the mass transfer step between gaseous CO2 and liquid absorbent. In this work, comparison of overall volumetric gas-phase mass transfer coefficient (KGav) of CO2 in solution of alkanolamine (Monoethanolamine, 2-(methylamino)ethanol and Dimethylaminoethanol) was comprehensively examined within a packed-bed absorption column containing Raschig ring packing. Effect of alkanolaime types, concentration and solvent flow rate were experimentally investigated under the atmospheric pressure and temperature. Typically, MEA with a concentration of 3.0 kmol/m3 could provide the KGav value of 0.36 kmol/(m3·kPa·h). Meanwhile, KGav of CO2 in 2-MAE could achieve the highest value of 0.73 kmol/(m3·kPa·h) when 2-MAE solution was supplied with a concentration of 5.0 kmol/m3. All of experimental results revealed that 2-MAE exhibited the highest KGav when compared to those of other two alkanolamine species, suggesting that 2-MAE would be a potential absorbent effective for CO2 capture and storage application.