Modeling of the Solubility of Solids in Supercritical Fluids/Supercritical Fluids-Cosolvent Systems using Peng-Robinson Equation of State

Abstract

Abstract The Peng-Robinson equation of state (PR EOS) was used for modeling the solubility of solids in supercritical fluids (SCFs). A correction function is introduced to the van der Waals one-fluid mixing rules for EOS parameter b for considering the effect of solute molecules on the volumetric properties of solvent molecules. The calculated results by PR EOS are satisfactory when the temperature-independent interaction parameters are applied to 20 supercritical binary systems containing supercritical carbon dioxide, ethylene and ethane, giving equivalent correlative accuracy by the SAFT EOS, which has a sound theoretical basis. The solubilities of solids in carbon dioxide with ethane as cosolvent ternary systems were predicted using the parameters obtained from binary systems. The solubilities of other systems are also predicted by setting the interaction parameters as zero. The results suggested that a simple PR EOS model can predict the gas-solid phase equilibrium of supercritical fluid with reasonable accuracy.