NEW PROCEDURES FOR APPLICATION OF THE WONG-SANDLER MIXING RULES TO THE PREDICTION OF VAPOR-LIQUID-EQUILIBRIA

New procedures are developed for use with the recent Wong-Sandler mixi ng rules for the prediction of mixture phase equlibria from cubic equa tions of state. Improvements in the apriori evaluation of both the liq uid-phase parameter A(infinity)(E) and the gas-phase parameter B-12(EO S) (or K-12) are made. An important new procedure is developed where t he latter parameter is found from experimental measurements of the cro ss second virial coefficient B-12(Exp) in the single-phase vapor mixtu re at low pressures. Apriori prediction of phase eqilibria to high pre ssures and temperatures then follows when the liquid-phase parameter A (infinity)(E) is estimated from a group-contribution method, such as U NIFAC. An order-of-magnitude analysis shows the resultant phase equlib ria to be more sensitive to the gas-phase parameter B-12(EOS). These n ew procedures are most promising in the prediction (not correlation) o f the phase behavior of complex systems, such as CO2/H2O/oil in petrol eum reservoirs undergoing CO2 and/or steam flooding.