Kinetics of the Absorption of Pure CO2 by Mixtures of Diisopropanolamine and Triethanolamine in Aqueous Solution

This study analyzes the absorption of pure carbon dioxide in aqueous solutions of mixtures of di-isopropanolamine (DIPA) and triethanolamine (TEA). A stirred tank batch reactor was used with a known flat interface area. The variables considered were temperature within the range 288-313 K and concentration in the interval 5-20% (in weight), being DIPA/TEA relations 75/25, 50/50, and 25/75. The temperature control for the DIPA/TEA 75/25, 50/50, 25/75 systems in the absorption experiments, at all the concentrations and temperatures assayed, showed no differences between that of the liquid phase with respect to the operation, implying that the processes occurred under isothermal conditions. The results show that for the DIPA/TEA 75/ 25 CO2 was absorbed in a moderately fast reaction regime, following a second-order reaction for the total alkanolamine and a first-order reaction for the CO2, whereas for the DIPA/TEA 50/50 and 25/75 systems the process followed first-order kinetics with respect to CO2 and the mixture of alkanolamines, in a moderately fast reaction regime. (C) 2017 Wiley Periodicals, Inc.