Extending a classical EOS correlation to represent solid–fluid phase equilibria

A strategy is presented for describing all the solid–fluid phase equilibria of a binary mixture, by combining a classical equation-of-state with a general mathematical artifice for the fugacity of the solid phase. As a case study, the strategy is applied to predict the solid–fluid phase equilibria of the binary mixture methane + carbon dioxide using the Soave–Redlich–Kwong equation-of-state to represent all real and hypothetical fluid phases. A system stability criterion is used to identify the slg locus, which is the intersection of the sl and sg equilibrium regions.