Experimental study and modified modeling on effect of SO2 on CO2 absorption using amine solution.

[Display omitted] • The overall CO 2 mass transfer coefficient decreased under exposure to SO 2. • pH variation of amine solution increased in the presence of SO 2. • The saturated CO 2 capacity largely decreased under exposure to SO 2. • SO 2 greatly weakened the interaction between amine and CO 2. • Modification of overall CO 2 mass transfer coefficient considering the effect of SO 2. Understanding the competitive mechanism in absorption process between SO 2 and CO 2 is essential for simultaneous absorption of SO 2 and CO 2. In this study, the effect of SO 2 on CO 2 absorption using amine solution was studied experimentally and theoretically. The CO 2 absorption rates in MEA/MMEA/MDEA solutions were determined using wetted wall column. Results showed that the reduction of flue gas temperature was beneficial for CO 2 absorption at the typical coal-fired flue gas CO 2 concentration. On this basis, the effect of SO 2 on CO 2 absorption performance was studied. Firstly, the overall CO 2 mass transfer coefficient decreased under exposure to SO 2. Secondly, in the presence of SO 2 , pH variation of amine solution increased. In addition, the saturated CO 2 capacity largely decreased when SO 2 was continuously bubbled into the solution. Furthermore, the quantum chemical calculation showed that CO 2 had little effect on the absorption performance of SO 2 whereas SO 2 greatly weakened the interaction between CO 2 and amines. The overall CO 2 mass transfer coefficient was modified considering the effect of SO 2. The competitive absorption factor, χ, was introduced to modify the CO 2 liquid phase diffusion coefficients. The average deviation of overall CO 2 mass transfer coefficient narrowed to 1.76 % (0.5 mol/L MEA), 1.13 % (1.0 mol/L MEA), 1.88 % (1.0 mol/L MMEA) and 1.43 % (1.0 mol/L MDEA) respectively, which agreed well with the experimental results. [ABSTRACT FROM AUTHOR]