Theoretical methods for the prediction of phase equilibria in hydrogen-containing mixtures

Abstract

The ability of various theoretical methods to accurately predict vapour-liquid equilibria in hydrogen-containing binary mixtures with N 2, Ar, CO, CO 2, CH 4, C 2H 4, C 2H 6 is investigated. These methods include both traditional cubic equations of state (the Peng-Robinson and original Redlich-Kwong) and a recently developed equation of state due to Deiters. Calculations are also performed with a spherical reference based perturbation theory. The results of all three approaches are compared to recent experimental data due to Streett and co-workers. It is shown that the cubic equations provide an adequate representation of the data for the simpler fluids but are poor for the more complex ones (e.g. C 2H 4, C 2H 6). The Deiters equation gives very good results for all but the most complex fluid mixtures. The perturbation theory results are somewhat mixed, being unexpectedly poor for the simplest fluids (Ar, N 2) but improving with the molecular complexity of the fluid to provide the best description of the hydrogen-ethylene and hydrogen-ethane mixtures, the hardest to predict using equation of state methods.