A Study on CO2 Absorption Kinetics by Aqueous Solutions of N,N-Diethylethanolamine and N-Ethylethanolamine

N-Ethylethanolamine (EEA) and NN-diethylethanolamine (DEEA) represent promising candidate alkanolamines for CO2 removal from gaseous streams, as they can be prepared from renewable resources. In this work, the reaction rate constant for the reaction between CO2 and EEA was determined from the absorption rate measurements Of CO2 in a blend comprising DEEA, EEA and H2O. A stirred-cell reactor with a plane, horizontal gas-liquid interface was used for the absorption studies. While the DEEA concentration in the formulated solution was varied in the range of 1.5-2.5 kmol/m(3), the initial EEA concentration was 0.1 kmol/m(3). A zwitterion mechanism for EEA and a base-catalyzed hydration mechanism for DEEA were used to describe the reaction kinetics. At 303 K, the second-order reaction rate constant for the CO2 reaction with EEA was found to be 8041 m(3)/(kmol s). The liquid-side mass transfer coefficient was also estimated, and its value (0.004 cm/s) is in line with those typical of stirred-cell reactors.