Modified Heterogeneous Catalyst-Aided Regeneration of CO₂ Capture Amines: A Promising Perspective for a Drastic Reduction in Energy Consumption

In the CO2 capture process, decreasing the energy consumption and increasing the desorption rate of loaded MEA-CO2 during the regeneration process of monoethanol amine have been identified as major challenges that need to be addressed. To overcome these challenges, three modified heterogeneous mesoporous catalysts, CMK-3-SiO2, CMK-3-MCM-41, and CMK-3-SBA-15, and a SO42–/ZrO2 solid acid catalyst were initially synthesized and investigated to determine their catalytic effectiveness in the process of CO2 and MEA solvent regeneration with a CO2 loading of 0.5 ± 0.02 mol CO2/mol MEA at 97 °C. According to the experimental results, the CMK-3-modified catalyst significantly decreased the energy requirement for CO2 desorption. The catalytic performance of the synthesized catalysts was in the order of CMK-3-SiO2 > CMK-3-MCM-41 > CMK-3-SBA-15 > SZ. CMK-3-SiO2 exhibited the best catalytic performance by enhancing the desorption rate by 195%, and decreasing the energy requirement by 37.41% compared to monoethanol amine as a blank run. Furthermore, the CMK-3-SiO2 catalyst exhibited the best catalytic performance compared to the literature with excellent stability and no unfavorable effects on the MEA-CO2 absorption activity for the regenerated amine solvent. This performance seems to be a result of the large mesoporous surface area (BET) and the large number of Brϕnsted and Lewis acid sites. In addition, a reasonable reaction mechanism for amine solvent regeneration with the CMK-3 heterogeneous catalyst is proposed.