Revised kinetics of CO2 absorption in aqueous N,N-diethylethanolamine (DEEA) and its blend with N-methyl-1,3-propane-diamine (MAPA)

Abstract

The absorption of CO2 into aqueous solution of N,N-diethylethanolamine (DEEA) and its blend with N-methyl-1,3-propane-diamine (MAPA) is studied in a batch-operated stirred-cell reactor under fast pseudo-first order regime. Since the literature data on the kinetics of CO2 reaction in aqueous DEEA are inconsistent, new kinetic data are obtained over the temperature range of 303–333K. At 318K, the reaction rate constant of 168m3/(kmols) is determined. Taking the recent findings into considerations, the reasons for the scatter in the reported kinetics are critically discussed. The analysis of literature data reveals the high sensitivity of the reaction rate constant to the value of CO2 solubility and the chosen method of data treatment. The need for a standardized procedure to determine the kinetics of gas-liquid reactions is emphasized. Furthermore, it is found that a fast reacting MAPA acts as an effective absorption activator in aqueous DEEA solutions. A small amount of MAPA in the DEEA solutions results in a considerable enhancement of the CO2 absorption rate as compared to DEEA alone.