Fluid Phase Equilibria, Vol.129, No.1-2, 61-67, 1997
Prediction of Hydrocarbon and CFC Liquid-Mixtures Densities
In this work, we apply an equation of state based on statistical-mechanical perturbation theory to liquid mixtures. Three temperature-dependent quantities are needed to use the equation of state (EOS) : the second virial coefficient, B(T), effective van der Waals covolume, b(T), and a scaling factor, (alpha(T). The second virial coefficients are calculated from a correlation that uses the heat of vaporization (e.g. Trouton’s rule), Delta H-vap, and the density at the triple point, p(tp). alpha(T) and b(T) can also be calculated from the second virial coefficient by scaling. Based on the theory, all the three temperature-dependent parameters depend only on the repulsive branch of the potential function, and therefore, by our procedure, can be found from Delta H-vap, and p(tp). It has considerable predictive power, since it only permits the construction of the P-v-T surface from the heat of vaporization plus triple-point density. The equation of state is tested for three-, four-, and five-component liquid mixtures.