Studies On Vapor Pressures Of New Refrigerants And Vapor-Liquid Equilibria Of Hydrofluorocarbon Mixtures

Chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) cause ozone layer depletion and global warming. Thus research on thermophysical properties of their alternatives becomes a hot issue. Hydrofluorocarbon (HFC), Hydrocarbon (HC) and dimethyl ether (DME) are assumed promising alternatives. Refrigerant mixtures call people's attention because they can be blended to meet the demands for alternatives. Vapor-liquid equilibria (VLE) is one of the most important properties of pure and blended refrigerants, and it is important for optimization of refrigeration and other thermophysical properties of alternatives.The PR EoS and the van der Waals mixing rule were used to study the VLE of HC+HFC and DME+HFC mixtures. Binary interaction parameters have been correlated to calculate the VLE property with high accuracy. Two new correlations for the binary interaction parameters have been proposed to the above systems, which can predict the binary interaction parameters by critical compression factors of pure substances. The correlations can represent the properties of VLE very well for both binary and ternary mixtures.Both EoS and mixing rule can affect VLE calculation. On one side, this work coupled the PR EoS with four typical mixing rules, evaluated their capabilities for binary and ternary mixtures containing HFC. On the other side, the CPA EoS was applied to mixtures of halogenated hydrocarbon and alcohol. By introducing association into a cubic EoS, CPA EoS can accurately describe the VLE property of alcohol contained refrigerant mixtures, with consideration of the interactions between molecules.This work also measured the vapor pressures of HFC-227ea and HFC-245fa. Two corresponding vapor pressure equations were developed on the basis of present measurement and available data, respectively. Then the normal boiling points and acentric factors of HFC-227ea and HFC-245fa were determined.