An Aprotic Polar Solvent, Diglyme, Combined with Monoethanolamine to Form CO2 Capture Material: Solubility Measurement, Model Correlation, and Effect Evaluation

In this work, an aprotic polar solvent, diethylene glycol dimethyl ether (diglyme), rather than H2O, was used to dissolve monoethanolamine (MEA) to form a physical-chemical absorbent for CO2 capture. An isothermal synthesis method was used to measure the CO2 solubility in MEA + diglyme at temperatures of 293.15-333.15 K, at pressures as high as 1200 kPa, and at MEA concentrations of 0-45%. An extended Antoine equation was used to fit the experimental data, and model parameters were obtained. The maximum average absolute relative deviation between the experimental and fitted data was 3.12%. The effects of pressure, MEA concentration, and temperature on the CO2 solubility under the experimental conditions are discussed. The CO2 solubility in MEA + diglyme was compared with literature data on CO2 solubility in MEA + H2O. The MEA + diglyme absorbent was found to perform better than the traditional MEA + H2O absorbent when the pressure exceeded a certain value.