PREDICTION OF VAPOR-LIQUID-EQUILIBRIA AT HIGH-PRESSURES USING ACTIVITY-COEFFICIENTS AT INFINITE DILUTION

A modified procedure of using the Huron-Vidal mixing rule based on ava ilable activity coefficients at infinite dilution at low pressures is shown to be useful for making vapor-liquid equilibrium predictions for non ideal mixtures at high temperatures and pressures. We compare the performances of this mixing rule (called HVID model), coupled with th e SRK equation of state and a reduced UNIQUAC model, with those of two other equation of state mixing rules, one by Dahl and Michelsen (MHV2 ) and another by Wong and Sandler (WS). Six binary systems are used in this study, and we find that the errors in the predicted pressure wit h the new mixing rule are, on the whole, less than those obtained when using the MHV2 model. Compared with the WS mixing rule, the HVID mode l performs slightly better.