Studies On Perturbed-Soft-Chain EOS And Vapor-Liquid Equilibria For The Halogenated Hydrocarbon Mixtures

As CFCs and HCFCs refrigerants deplete the ozone layer and cause theglobal warming, which are widely used in refrigeration, air-conditioning andheat pump industrial fields, the research on the thermophysical properties ofCFCs and HCFCs alternatives becomes a hot issue. Meanwhile, there has beenincreasing interest in using saturated hydrocarbon as one of the component ofthe refrigerant mixtures.The vapor-liquid equilibria (VLE) property is one of the most importantthermodynamic properties for pure and blended refrigerants, and it isnecessary for optimization design of refrigeration or air-conditioningequipments.For PR, SRK and CSD equations of state (EOS), the VLE experimentaldata have been correlated and the interaction parameters of many binaryrefrigerant mixtures have been obtained. The calculated results using theequations of state with the optimized kij shows very good agreements with theexperimental data.Based on the accentricity and reduced dipole moment, a new correlationfor the binary interaction parameters kij has been proposed. The correlationrepresents the properties of VLE very well by comparing with theexperimental data and the other correlations before.An EOS based on Perturbed-Soft-Chain Theory has been used tocalculate the thermophysical properties of halogenated ethanes. The equationcontains three parameters and the parameters of 12 kinds of halogenatedethanes have been fitted to experimental data for saturated vapor pressure andsaturated liquid density. Comparison of the EOS predictions with NISTREPROP 7.1 shows that this EOS can accurately represent the pvT data in thesingle-and two-phase regions. The parameters also follow a pattern that isrelated to the molecular structure.