Molecular simulation with an EOS algorithm for vapor–liquid equilibria of oxygen and ethane

A molecular simulation methodology with an algorithm usually used in equation of state calculations for phase equilibria (EOS algorithm) is applied to calculations of vapor–liquid equilibria of pure oxygen and ethane. This method can be used to determine fluid phase equilibria of pure substances and/or multicomponent mixtures by performing a single simulation, and any kinds of method to determine chemical potentials can be used. Molecular simulations of vapor–liquid equilibria for pure oxygen and ethane are performed in a very wide temperature range, from the triple points to the critical points. A two-center site–site potential model is used for oxygen and ethane, and the potential parameters are empirically determined from comparisons with experimental saturation properties. For the site-site potential function, the Lennard–Jones (LJ) potential and the Barker–Fisher–Watts (BFW) potential are used. The simulation results using the BFW potential gave better agreement with the experimental saturation properties.