Evaluation of the Truncated Perturbed Chain-Polar Statistical Associating Fluid Theory for Complex Mixture Fluid Phase Equilibria

Perturbed chain-statistical associating fluid theory (PC-SAFT) was extended rigorously to polar fluids based on the theory of Stell and co-workers [Mol. Phys. 1977, 33, 987]. The new PC-PSAFT was simplified to truncated PC-PSAFT (tPC-PSAFT) so that it can be practical for real polar fluid thermodynamic calculations. In this work, tPC-PSAFT is generalized to multicomponent mixtures and evaluated for a wide range of highly nonideal polar mixtures. Binary and ternary mixtures of dipolar, quadrupolar, and/or associating fluids are examined. Vapor-liquid and liquid-liquid equilibria at low and high pressures are calculated. Comparisons against PC-SAFT calculations are made. It is shown that tPC-PSAFT is an accurate model for polar fluid mixture phase equilibria.