Solubility of solids in supercritical fluids using equations of state — excess Gibbs free energy models

Abstract

Solubilities of several organic solids in four supercritical fluids are calculated with Soave and Peng-Robinson equations of state, incorporating excess Gibbs free energy into the mixing rules, with Heidemann-Kokal, Wong-Sandler and MHV2 procedures. Three excess Gibbs free energy models are used in the mixing rules: NRTL, UNiQUAC and UNIFAC. Furthermore, a comparison between these mixing rules and conventional two-binary-parameter form and modification of the excluded volume parameter in the MHV2 procedure is also presented. The best result were obtained with NRTL model and the Wong-Sandler mixing rule.