Correlation and Prediction of Binary Vapor-Liquid Equilibrium in Systems Containing Gases, Hydrocarbons, Alcohols, and Water

Optimal binary interaction coefficients have been determined for a generalized equation of state for associating mixtures using a large data base of 170 binary systems compiled from the literature. The data base covers gases (H₂, N₂, CO, CO₂, and H₂S), hydrocarbons, alcohols, and water. Results show substantial improvements in accuracy for the equation of state presented here relative to the Soave equation. Average errors in estimated bubble point pressure ranged from 2.1% to 8.7% for CH₄, H₂S, N₂, CO, CO₂, H₂, H₂O, MeOH, and EtOH systems when optimal binary interaction coefficients were used. The accuracy for the gaseous components is roughly equivalent to that of the Soave equation, but for water, methanol, and ethanol systems, the optimized Soave equation provides 20%, 15%, and 10% error. For systems without optimal binary interaction coefficients, predictive methods were developed. For predictions treating nongaseous components, errors in estimated bubble point pressure ranged from 0.7% to 8.1% when this method was applied. For predictions treating gaseous components, errors in estimated bubble point pressure ranged from 5.0% to 37.6% for CH₄, H₂S, N₂, CO, CO₂, and H₂ when the predicted interaction coefficients were applied. Tables of optimal binary interaction coefficients where available and estimated interaction coefficients where necessary are presented for roughly 350 binary systems over a wide range of temperatures and pressures.