Kinetics of absorption of carbon dioxide into aqueous solutions of 2-amino-2-methyl-1-propanol plus monoethanolamine

Kinetics of the absorption of CO2 into 2-amino-2-methyl-1-propanol (AMP) + monoethanolamine (MEA) + water were investigated at 30, 35, and 40 degrees C using a laboratory wetted wall column. Ten systems of which 1.7 and 1.5 kmol m(-3) AMP mixed with various MEA concentrations (0.1, 0.2, 0.3, and 0.4 kmol m(-3)) were studied. Densities and viscosities of 10 blended amine systems were measured. The solubilities and diffusivities of N2O in amine systems were also studied. The N2O analogy was applied to estimate the solubilities and diffusivities of CO2 in amine systems. Based on the pseudo-first-order for the CO2 absorption, the overall pseudo-first-order reaction rate constants were determined from the kinetic measurements. The addition of small amounts of MEA to AMP results in a significant enhancement of CO2 absorption rates. A hybrid reaction rate model, a first-order reaction for MEA and a zwitterion mechanism for AMP was used to model the kinetic data. The model is satisfactory to represent CO2 absorption rates in AMP + MEA aqueous systems. (C) 1999 Elsevier Science Ltd. All rights reserved.