SIMULTANEOUS REPRESENTATION OF EXCESS ENTHALPY AND VAPOR-LIQUID-EQUILIBRIUM DATA BY THE NRTL AND UNIQUAC MODELS

Using data for excess Gibbs energy, g(E), and enthalpy of mixing, h(E), temperature-dependent parameters of the NRTL and UNIQUAC models have been estimated for 44 systems of binary mixtures. Thirty-three of them include data for g(E) and h(E) at more than one different isotherm. The estimated parameters were later tested by predicting the total pressure, vapor-phase compositions and g(E) and h(E) data simultaneously and representing the effect of temperature on such data. System-dependency of the models, non-uniqueness in the parameters and the possibility of predicting partial miscibility for completely miscible non-ideal mixtures have been investigated.