Calculation of high-pressure vapor-liquid equilibria of non-polar asymmetric mixtures with an augmented van der waals equation of state

An augmented van der Waals equation of state developed in a previous study was applied to the calculation of high-pressure vapor-liquid equilibria of non-polar asymmetric mixtures. The equation of state for a non-polar substance comprised three terms, each of which was classified into repulsion, symmetric interaction and non-polar asymmetric interaction. Two types of mixing models based on the one-fluid model, that is, the van der Waals one-fluid model and a semiempirical mixing model of Kreglewski and Kay, were tested for both repulsion and symmetric interaction terms, while two types of semiempirical mixing models based on the one-fluid model and on the three-fluid model were developed for the non-polar asymmetric interaction term. This method, which applied a separate mixing model to each interaction term, provided good correlation results for the high-pressure vapor-liquid equilibria of non-polar asymmetric mixtures.