Document Type : Regular Article
Shiraz University of Technology
In this paper, the vapor-liquid equilibrium (VLE) properties of polar and nonpolar fluids are modeled by the use of a statistically-based equation of state (EOS). The equation of state used in this work is that of Ihm-Song-Mason (ISM) EOS. An alternative approach is to revise the isothermal integration on liquid. In this respect, a temperature-dependent revision factor b (T) is introduced to the liquid fugacity coefficient expression which was already derived from traditional isothermal integration. By this modification, the vapor pressure of pure liquids can be successfully reproduced using ISM EOS. This equation of state originally cannot predict the vapor pressure of fluids. The novelty of the present work is to introduce a method such that the ISM EOS is able to predict vapor pressure of pure substances and mixtures. Furthermore, the revisionzaSX method is extended to represent the VLE properties of binary mixtures including noble gases, refrigerants and hydrocarbons. Our computation results on the VLE and PVT behaviors of 24 pure substances and 9 binary mixtures are impressive.