Predicting phase behavior in aqueous systems without fitting binary parameters II: Gases and non-aromatic hydrocarbons



This investigation continues a series of studies evaluating the capability of the recently proposed CP-PC-SAFT and sPC-SAFT of Liang et al. to estimate the thermodynamic properties of aqueous systems in the entirely predictive manner. Similarly to the previously considered systems, CP-PC-SAFT remains a realistic estimator of the available data on critical loci, high pressure-high temperature phase equilibria and volumetric properties also in the cases of non-polar gases and non-aromatic hydrocarbons from argon and nitrogen till n-eicosane and squalene while keeping zero values of binary parameters. Nevertheless, such application of the model poses certain unavoidable compromises on its accuracy. Inter alia, CP-PC-SAFT is a particularly inaccurate estimator of the water-rich liquid phases away from the critical points. sPC-SAFT predicts these data in a more reliable manner. Moreover, its predictive capability goes beyond the liquid phases and it exhibits a remarkable accuracy in forecasting various phase equilibria below the critical point of water. © 2017 American Institute of Chemical Engineers AIChE J, 2017