Comparative Study of Linear Co-Volume Based Mixing Rules for Equation of State/ Excess Gibbs Energy (EOS/G^E) Models for CO₂ – MEA and CO₂ – MDEA Systems

With the advent of Equation of State/ Excess Gibbs Energy (EOS/GE) models, the linear co-volume based mixing rules have gained vast importance for predicting multi-component VLE for polar mixtures. Owing to their inherent ease of calculation and good prediction abilities, these mixing rules have been applied in extension, to a variety of systems especially for CO2-H2O-alkanolamine systems. However, no comparative study is available to select appropriate mixing rule for prediction of thermodynamic properties. In this study, pressure prediction of various linear co-volume mixing rules has been compared for CO2 – MEA and CO2 – MDEA systems, while effects of activity coefficients and process parameters have been kept constant. The infinite pressure mixing rules have heavily under – predicted and approximate zero reference pressure mixing rules have over – predicted, but latter are valid for low and medium pressure ranges. The linear combination of Vidal and Michelsen (LCVM) mixing rule have good predictions at high pressures.