Below the room temperature measurements of CO2 solubilities in six physical absorbents

An isothermal synthetic apparatus was established as the absorbing device. Six physical absorbents with ether and ester groups were selected: ethylene glycol methyl ether acetate (EGMEA), propylene glycol methyl ether acetate (PGMEA), 3-methoxy butyl acetate (MBA), diethylene glycol diethyl ether (DGDE), ethylene glycol butyl ether acetate (EGBEA) and carbitol acetate (CA). CO2 solubilities in the selected absorbents were measured at temperatures of 273.15-283.15 K, and pressures up to 1.2 MPa. Henry's constants of CO2 + selected absorbents systems at 273.15 K and 283.15 K were regressed and compared with those at higher temperature. It turned out that decreasing the temperature has a large effect on improving absorption capacity. Henry's constants and volumetric solubilities of the selected absorbents were compared with other solvents and ionic liquids for the purpose of judging the absorption capacity. CA and EGMEA were found to be relatively good absorbents by mole and volumetric fraction respectively, and they have potential value for CO2 capture. In order to study absorption behavior, thermodynamic properties such as entropy of solution, enthalpy of solution and Gibbs free energy of solution for the selected systems were calculated and assessed.