The enhancement of the rate of absorption of CO2 in amine solutions due to the Marangoni effect

Results of the experimental and theoretical investigations of the occurrence of cellular convection during absorption of CO2 in amine solutions (Marangoni effect) are presented. Experiments in CO2-aqueous solutions of MEA and CO2-aqueous Solutions of DEA systems show that cellular convection indeed occurs during chemisorption and that it can increase mass transfer rate significantly enough to lower the absorber height. The influence of certain parameters characterizing mass transfer (e.g. mass transfer coefficient in the liquid phase, initial concentrations of reactants, presence of surface-active agents) on the intensity of cellular convection is analyzed. Theoretical considerations confirm the possibility of the occurrence of cellular convection in the systems investigated. Experimental correlations are given which describe the influence of the effect in terms of the mass transfer enhancement factor. The results can be directly employed in the design of absorbers for CO2 capture. (C) 1997 Elsevier Science Ltd.