The Henry coefficient of CO₂ in the MEA-CO₂-H₂O system

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 °C.