Comprehensive mass transfer and reaction kinetics studies of CO₂ absorption into aqueous solutions of blended MDEA-MEA

In the present work, the reaction kinetics and mass transfer performance of CO₂ absorption into aqueous solutions of blended MDEA-MEA solutions were comprehensively studied. The reaction kinetics was investigated using a laminar jet absorber in terms of a second order reaction rate constant and enhancement factor. The mass transfer performance was evaluated experimentally in a lab-scale absorber packed with high efficiency DX structured packing in terms of CO₂ concentration profile and over all mass transfer coefficient (K_Ga_v). The experiments were conducted over the MDEA/MEA concentrations of 27/3, 25/5, and 23/7wt% MDEA/wt% MEA (which equivalent to MDEA-MEA molar ratios of 2.3/0.5, 2.1/0.8, and 1.95/1.16M, respectively). It was found that k_MEA was successfully extracted and can be expressed as: _{k MEA} = (5.127 × ¹⁰⁸)exp -3373.8T. The results also show that the operating parameters (i.e., MDEA-MEA blended ratio, temperature, and CO₂ loading) affect both the reaction kinetics and mass transfer performance significantly. Lastly, the MDEA-MEA blended ratio of 1.95/1.16 provided the highest reaction kinetics and mass transfer performance among the three concentrations investigated in this study.