Vapor–Liquid Equilibria of the CH 4 + CO 2 + H 2 S Ternary System with Two Different Global Compositions: Experiments and Modeling

The vapor-liquid equilibrium for two mixtures containing methane, carbon dioxide and hydrogen sulphide was determined experimentally by a static-analytic method. Thirty-one data points were acquired for a range of temperatures from 243 K to 333 K at pressures up to 11 MPa. The measured data were correlated with the Peng Robinson equation of state (EoS) and different mixing rules, which led to the conclusion that a cubic EoS could simultaneously predict the existence of a 3-phase region and 2 critical points on the constant-composition two-phase boundary curve.