Analysis and predictive correlation of mass transfer coefficient KGav of blended MDEA-MEA for use in post-combustion CO2 capture

The mass transfer performance of the absorption of CO2 in aqueous blended MDEA-MEA solutions was evaluated experimentally in a lab-scale absorber packed with high efficiency DX structured packing over MDEA-MEA concentrations of 27/3, 25/5, and 23/7%wt under atmospheric pressure using a premixed feed gas containing 15% CO2 balanced with N2. The absorption performance was presented in terms of overall mass transfer coefficient (KGav) and CO2 concentration profile. The results showed that the mass transfer performance increased as ratio of MEA in the blended solution, temperature, and liquid flow rate increased but decreased as CO2 loading increased. In addition, it was found that the cyclic capacity and relative solvent regeneration ability decreased as the ratio of MEA in the blended solution increased. Based on mass transfer performance, cyclic capacity, and relative solvent regeneration ability, 23/7%wt MDEA-MEA was found to be the most effective blend ratio among the three ratios investigated in the present work. Also, the correlation for predicting KGav for CO2 absorption into aqueous blended MDEA-MEA was successfully developed with an AAD of 21.8%.