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

Abstract

The Henry Coefficient of CO2 is a fundamental property and crucial for the accurate simulation of the absorption and desorption of CO2 in MEA solutions related to post combustion capture (PCC). The free CO2 concentration in amine solutions is very small and is difficult to be measured since it reacts with the solution. The “N2O analogy” is traditionally applied to estimate the physical solubility of CO2 based on the assumption that the two gases behave similarly in amine solutions. We propose a direct way to determine Henry Coefficient of CO2 in MEA solutions as an alternative to N2O analogy. The method only requires vapor liquid equilibrium measurements of the MEA-CO2-H2O system. Based on the total MEA concentration, loading and known equilibrium constants the free CO2 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 CO2 concentration at 40 oC.