1988 Volume 21 Issue 2 Pages 147-157
A simple DDLC-EOS (density-dependent local-composition model combined with equations of state) unified model based on a conformal mixture as the reference state is proposed.
Its applicability has been tested on more than 100 binary high-pressure vapor-liquid equilibrium data for several types of mixtures. For systems containing strongly polar and nonpolar substances or for some asymmetric mixtures, its fitting accuracies have been remarkably improved over those using the conventional Soave-Redlich-Kwong, Peng-Robinson and Patel-Teja equations of state. The proposed model is also capable of correlating vapor-liquid equilibria of nonpolar mixtures with the same or a slightly better accuracy than those cubic equations of state with the quadratic mixing rule.
In addition, model energy parameters obtained from the data reduction of constituent binaries were then applied to predict vapor-liquid equilibria of several ternary systems. Predicted results were also better than those by conventional methods.
