Solubility of N2O and CO2 in non-aqueous systems of monoethanolamine and glycol ethers: Measurements and model representation

Abstract

Non-aqueous mixtures of monoethanolamine (MEA) with glycol ethers as low viscosity absorbents have potential advantages for CO2 capture. In this work, physical solubility of N2O and CO2 in glycol ethers (2-methoxyethanol and 2-ethoxyethanol) and their blends with MEA was measured and correlated at temperatures ranging from (293.15 to 333.15) K. Physical solubility of CO2 in the blends was also estimated by N2O/CO2 analogy method. A mathematic model based on the reaction mechanism was proposed to interpret the vapour-liquid equilibrium data for the systems of CO2/MEA/glycol ether solution. Results show that glycol ethers have greater ability to dissolve CO2 than glycols and water. The apparent chemical equilibrium constant was obtained and correlated as a function of temperature by non-linear regression. The proposed model could reasonably fit the experimental data with an average absolute deviation within 10%. The heat of absorption of CO2 in MEA/glycol ether systems was also calculated.