CORRELATION AND PREDICTION OF PHASE-EQUILIBRIA IN LIQUID-MIXTURES BY MEANS OF THE UNIQUAC EQUATION

The prediction of Vapor-Liquid Equilibrium data (VLE) from Excess Enth alpy (h(E)) data by means of the Hanks-Gupta-Christensen (HGC) method was examined. VLE data for a variety of binary and ternary mixtures ca n be succesfully predicted using this method in conjunction with an ap propiate model for the Excess Gibbs Energy (g(E)). In this study, the well known UNIQUAC model for (g(E)) was chosen. Correlation of VLE dat a using this equation was examined. Results from this correlation were compared with VLE data predicted from h(E) data by means of the HGC m ethod and good agreement was found. In this prediction, the parameters of the UNIQUAC model are evaluated by fitting the experimental h(E) d ata to the algebraic equation for h(E) derived from the g(E) model. Th e dependence of the accuracy of the predictions on the experimental un certainties of h(E) data and the values obtained for the UNIQUAC param eters by fitting these data to the algebraic equation for h(E) was als o discussed.