Coupled CO2 absorption and mineralization with low-concentration monoethanolamine

Abstract

The high energy-consumption of Carbon Capture Utilization and Storage (CCUS) promote the study of coupled CO2 absorption and mineralization technology. CO2 absorption and mineralization are coupled into one step in mixed slurry of Ca(OH)2 and amine. And CO2 is mineralized to CaCO3 in normal temperature and pressure. The aqueous amine, such as monoethanolamine (MEA), is used as a capture intermediate to accelerate the absorption and mineralization. In this study, effects of concentration of MEA, reaction temperatures and concentrations of Ca(OH)2 are investigated. Furthermore, the performance of cyclic utilization of aqueous MEA is tested. The results demonstrate that in the coupled reaction CO2 capture capacity (0.98 mol CO2/L) is achieved in 0.05 mol/L MEA at 20 °C with 1 mol/L Ca(OH)2. The major polymorph of CaCO3 in the reaction is calcite, and the morphology is chain-like crystals. After ten cyclic utilization experiments, the extent of mineralization of CO2 with aqueous MEA is 78.38%. These results illustrate that the coupled absorption and mineralization technology can effectively capture and mineralize CO2 and reduce the energy consumption of CCUS.