PC-SAFT-Type Equations of State Revisited: Quantifying the Value of Base Model Adjustments through Universal Criteria Benchmarks

The statistical associating fluid theory (SAFT) equations of state have been extensively applied in diverse forms across various industrial fields. Within this investigation, based on a benchmark database encompassing binary systems with diverse association characteristics, perturbed-chain SAFT (PC-SAFT), perturbed-chain polar SAFT (PCP-SAFT), and simplified perturbed-chain SAFT (sPC-SAFT) were systematically incorporated into the same phase equilibrium evaluation framework for a fair comparison. Furthermore, some ternary systems are also considered as additional supplements to compare the performance of the models in predicting multicomponent mixtures. The comparison results show that PCP-SAFT and sPC-SAFT exhibit overall better performance than the original version, yet the latter continues to hold its absolute superiority in some mixtures with specific characteristics. Additionally, it is also demonstrated that any modification to the parent model is challenging to balance across various domains, and the resulting trade-offs appear to be an inherent limitation of SAFT variant development.