Simplified Approach to Understanding, Evaluating, and Parameterizing the NRTL Model for the Description of Binary VLE: Tττ-VLE Approach

Abstract

An improved understanding of the Non-Random Two Liquid model can improve the correlation of vapor liquid equilibrium (VLE) phase behavior beyond the trial-and-error approach often employed. This work provides a rigorous, systematic evaluation of the model’s capabilities to contribute unqualified, component-independent findings and recommendations─a limitation of previous studies. First, evaluations of the model’s isobaric and isothermal VLE prediction capabilities provide insight into multiple factors, including the influence of the model’s non-randomness parameter (0.20 and 0.47). Second, a new approach is presented to improve VLE correlation of common pressure maximum azeotropic behavior. It includes a method to unequivocally disqualify non-randomness parameter values based on a single azeotropic measurement. The approach further significantly simplifies the parameterization procedure by incorporating a priori knowledge, including parameter temperature dependence requirements and initial guesses therefor. The benefits of the presented approach are demonstrated in a case study on 17 (alcohol + hydrocarbon) binary systems.