Oxidative Degradation of Alkanolamines with Inhibitors in CO2 Capture Process

Abstract CO 2 absorption with reversible chemical reaction using aqueous amine solution is currently the most appropriate method for low pressure CO 2 source like a coal fired power plant. Solvents have been used extensively for the removal of CO 2 from natural gas and flue gas via chemical absorption. Among the industrially utilized solvents, alkanolamines are the most widely used for CO 2 absorption because of the properties toward CO 2 capture such as high absorption capacity, fast reaction kinetics, and high solubility. However, a major problem associated with the chemical absorption is solvent degradation. We examined the oxidative degradation of alkanolamines such as MEA, DEA, AMP, and MDEA. The oxidative degradation rate of the amines was in the order MEA > DEA > AMP = MDEA. The effect of oxidation inhibitors, EDTA and DTPMP, on the oxidative degradation of MEA was investigated and the products of oxidative degradation of MEA were analyzed. The oxidation inhibitors prevented the oxidative degradation of MEA and the extent of prevention was in the order EDTA > DTPMP. Among the products of the oxidative degradation of MEA in the oxidation condition, formate and acetate were the dominant degradation products, and EDTA and DTPMP decreased the products of oxidative degradation.