(52h) Prediction of Solid-Liquid-Gas Equilibrium for Binary Mixtures of Carbon Dioxide + Organic Compounds

The supercritical carbon dioxide is considered as a solvent for extraction of high-value chemicals and recrystallization and micronization of drugs. The solid-supercritical fluid equilibrium (SFE) and solidâ??liquidâ??gas equilibrium (SLGE) for binary mixtures of carbon dioxide + organic compounds are important information to understand and design processes with supercritical carbon dioxide. Both phase behaviors are investigated with experiments and thermodynamic models in literatures. Since measurements of the SLGE and SFE, especially at high pressure conditions, are challenging and costly, it is useful to estimate such information from a reliable thermodynamic models. In this study, the combination of Peng-Robinson-Stryjek-Vera equation of state (PRSV EOS) with the COSMO-SAC model through Gex-based mixing rules is applied to predict the SLGE for binary mixtures of carbon dioxide + organic compounds. Two different versions of COSMO-SAC models, the COSMO-SAC(2002) model originally proposed by Lin and Sandler and the COSMO-SAC(2010) model proposed by Hsieh et al., and two Gex-based mixing rules, Modified Huronâ??Vidal 1st-order (MHV1) and Wong-Sandler (WS) mixing rules, are studied. A total of eight combinations of methods and 16 binary mixtures are considered in this work to understand the effects of activity coefficient model and mixing rule on the prediction of SLGE.