In situ measurement of physical solubility of carbon dioxide in loaded aqueous monoethanolamine by Raman spectroscopy

Physical solubility is a physicochemical parameter necessary for reaction kinetic study and modeling CO2 separation process. When CO2 absorb into liquid phase and react with solvent, shift in chemical composition and equilibrium results in change in properties of solvent. As CO2 absorption is a continuous process with CO2 dissolving into partially loaded solution most of the time, availability of a robust technique to access unreacted CO2 dissolved in aqueous phase is crucial to study effect of CO2 loading on physical solubility. Current work investigates physical solubility of CO2 in loaded monoethanolamine (MEA) solution at elevated pressure conditions by direct measurement of unreacted CO2 dissolved in the solution using Raman spectroscopy. This spectroscopic method does not require N2O as surrogate gas, hence eliminates the need of N2O analogy to estimate solubility of CO2. Impact of varying CO2 loadings on Henry's constant is examined.