Monoethanolamine+2-methoxyethanol mixtures for CO2 capture: Density, viscosity and CO2 solubility

Non-aqueous amine-based absorbents are considered as a potential application for CO 2 removal from biogas to reduce energy consumption, due to lower heat capacity and evaporation enthalpy of organics than conventional water solvent. In this work, monoethanolamine (MEA) + 2-methoxyethanol (EGME) mixtures were proposed as a novel CO 2 carrier. The density and viscosity of CO 2 -free and CO 2 -loaded MEA + EGME solutions were measured at temperatures of (293–353) K, for 10–100 mass % MEA. CO 2 solubility in 31.0 mass% (5.0 M) MEA solutions was investigated at temperatures from 313 K to 393 K and CO 2 partial pressures up to 260 kPa. The excess molar volumes and the ratio of viscosity η · η EGME −1 were correlated by Redlich-Kister equation and Weiland’s model, respectively. The vapour-liquid equilibrium data were correlated by using a semi-empirical model, i.e. CO 2 partial pressure as a function of temperature and CO 2 loading. The predicted values and the measured data matched well each other, with AAD within 0.2% for density, 4.5% for viscosity and 19.5% for CO 2 solubility respectively.