Vapor‐Liquid Equilibria Predictions of Carbon Dioxide + Hydrogen Sulfide Mixtures using the CPA, SRK, PR, SAFT, and PC‐SAFT Equations of State

Abstract

Accurate vapor-liquid phase equilibria predictions of hydrogen sulfide and carbon dioxide mixtures are critical to the safe and economic design of gas processing and flow assurance technologies. In addition, inaccurate predictions of the vapor-liquid equilibria also can lead to erroneous hydrate phase equilibrium predictions. In this work, different equations of state are used to predict vapor-liquid equilibria for mixtures of hydrogen sulfide and carbon dioxide along with other hydrocarbons and various cross-associating components (including water, methanol, ethanol, monoethylene glycol) as well. The equations of state used in these predictions include the Cubic Plus Association (CPA), the Soave-Redlich-Kwong (SRK), the Peng-Robinson (PR), the Statistical Associating Fluid Theory (SAFT), and the Perturbed-Chain SAFT (PC-SAFT) equations of state. Five parameters of the CPA equation of state were determined for the associating components by simultaneous minimization of absolute errors using experimental saturated liquid densities and vapor pressures. Model accuracies were compared without using binary interaction parameters.