Optimized Binary Interaction Parameters for VLE Calculations of Natural Gas Mixtures via Cubic and Molecular-Based Equations of State

Abstract

The objective of this study is to analyze the performance of a selected collection of equations of state (EOS) for the prediction of vapor–liquid equilibrium of the components of a typical natural gas mixture. In this work, 13 biparametric, triparametric, and tetraparametric, widely used simple-cubic-type EOS and three complex, but state-of-the-art, molecular-based EOS are used. A simple, one-fluid-based mixing rule was applied for the extension to mixtures of the models. Binary interaction parameters for the different equations were calculated by correlation of available binary vapor–liquid equilibria data in the experimental literature, in wide temperature–pressure ranges, for the key binary systems relevant to natural gases. The results allow one to infer the performance of the different EOS commonly used for phase equilibria analysis in the natural gas industry, and to study how the different complexity of the studied EOS does (or does not) lead to an improvement in the quality of the predictions.