The Henry Coefficient of CO2 in the MEA-CO2-H2O System

Abstract The Henry Coefficient of CO 2 is a fundamental property and crucial for the accurate simulation of the absorption and desorption of CO 2 in MEA solutions related to post combustion capture (PCC). The free CO 2 concentration in amine solutions is very small and is difficult to be measured since it reacts with the solution. The “N 2 O analogy” is traditionally applied to estimate the physical solubility of CO 2 based on the assumption that the two gases behave similarly in amine solutions. We propose a direct way to determine Henry Coefficient of CO 2 in MEA solutions as an alternative to N 2 O analogy. The method only requires vapor liquid equilibrium measurements of the MEA-CO 2 -H 2 O system. Based on the total MEA concentration, loading and known equilibrium constants the free CO 2 can be computed which allows the determination of the Henry Coefficient. A 6-parameter polynomial is used to approximate the Henry Coefficient as a function of the total MEA concentration and total CO 2 concentration at 40 o C.