The refined e-NRTL model applied to CO2–H2O–alkanolamine systems

The electrolyte NRTL (e-NRTL) model by Chen (1982) and Chen and Evans (1986) is perhaps the most commonly used activity coefficient based thermodynamic model for industrial systems. It has been shown by Bollas et al. (2008) that the original e-NRTL model is inconsistent for systems with multiple cations and/or anions, in the same work the model equations for the so-called refined e-NRTL model were given. In this work the refined e-NRTL model is applied to CO2–H2O–alkanolamine systems. The interaction parameters of the refined e-NRTL model are regressed to partial pressure of CO2, binary vapour–liquid-equilibrium, freezing point depression data and excess enthalpy data. The model is in the end used to predict partial pressures and speciation for the CO2–H2O–MEA and CO2–H2O–MDEA systems.