Low energy phase change CO2 absorption using water-lean mixtures of glycine amino acid: Effect of co-solvent

Abstract

The most important restriction for the extensive application of water-based solvents in the large-scale post-combustion CO2capture is high required energy for solvent regeneration. Different effort has been attempted to reduce the energy penalty of CO2 absorption using chemical solvents. In this study, a novel water lean amino acid-based solvent was developed to reduce the acquired energy of CO2 absorption along with improving the CO2 absorption efficiency. The designated solvents are composed of potassium glycinate amino acid, water and co-solvents including ethanol (EtOH), 2-Ethoxyethanol (2EE), N-Methyl-2-pyrrolidone (NMP) and N,N-dimethylformamide (DMF). In order to investigate the effect of chosen co-solvents, different solutions with various weight percentages were prepared and examined in CO2 absorption. The attained results revealed that after absorption the formed phase at the top is the CO2-free phase that could be simply recycled back to the absorption column. It results in the reduction in the volume of solvent sent to regeneration column that can significant save energy. Increasing the weight percentage of co-solvent (reduction in water content) results in improving the absorption capacity of K-Gly, generally. The experiments revealed good evaluations for the absorption rate at different temperatures.