PREDICTION OF VAPOR COMPOSITIONS IN VAPOR-LIQUID SYSTEMS

A method of calculating vapor-liquid equilibria in multicomponent mixtures is described. No experimental information of multicomponent mixtures is necessary. The data needed can be obtained from the binaries. Two models were used to calculate the activity coefficients: the Wilson equation and the Black equation. The Black equation has been extended in order to make it possible to extrapolate to other temperatures. Parameters in the equations are calculated by a nonlinear least-squares fit of observed data. The efficiency of the method when using the Black and Wilson equations in predicting vapor-liquid equilibria has been compared. The efficiency in predicting equilibria at other temperatures, some more than 40° C. from those where data was obtained, has also been investigated. The Wilson equation has been more accurate in nearly all cases studied. © 1968, American Chemical Society. All rights reserved.