Modeling of the phase behavior of CO2 in water, methanol, ethanol and acetone by different equations of state

This paper deals with the modeling of the phase behavior of CO2 in water, methanol, ethanol and acetone. The phase equilibria of pure substances and binary mixtures are correlated using different equations of state: PC-SAFT, PCP-SAFT, CPA and GEOS. The adjustable specific coefficients of pure fluids are determined by regression of vapor pressure and saturated liquid and vapor densities data. For binary mixtures, the binary cross-interaction parameters are deduced by regression of the vapor-liquid equilibrium data for wide ranges of temperature and pressure. The obtained results show that the GEOS equation of state appears to be the most adequate in the modeling and prediction of the isothermal vapor-liquid phase behavior in the vicinity of the critical region. Moreover, the GEOS model is most adequate in the prediction of the three-phase liquid-liquid-vapor equilibria of CO2/water system at temperatures around and below the critical temperature of CO2 and a formation of a second rich-CO2 liquid phase. In addition, the dew curves of the water/CO2 system were most accurately predicted by the GEOS model. The isothermal-isobaric vapor-liquid equilibria of CO2/methanol/water and CO2/ethanol/water were predicted and the comparison with the literature data demonstrated some advantages to the GEOS equation of state.