A New four-parameter cubic equation of state for polar and non-polar fluids

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A new four-parameter cubic equation of state has been developed which can accurately predict the PVT behaviour of polar and non-polar fluids. Extensive PVT data for seventy-five pure components were used to compare the new equation to ten recently published cubic equations. Significant improvements in PVT predictions were obtained over extreme ranges of temperature and pressure. Other thermodynamic properties were evaluated including second virial coefficients, enthalpy, isobaric heat capacity, speed of sound, and Joule-Thomson coefficients. Prediction of these properties was generally good. Limitations on the use of temperature dependence in the "b" parameter have been identified and adhered to in this work. Violation of these restrictions have been shown in two recently published cubic equations of state with the result that they predict negative heat capacities under certain conditions. An extensive evaluation of quadratic mixing rules has been performed in this work for thirty-three binary sy sterns. As many as four binary interaction parameters have been utilized. All subsets of these interaction parameters have been optimized and recommended values are provided for each binary. In most cases it was possible to fit vapour-liquid equilibrium data very well with one or two interaction parameters, even though some very non-ideal binary systems were considered. A ternary system of water-methanol-acetone was predicted very accurately using binary interaction parameters regressed from binary VLE data only.
Bibliography; p. 221-233.
Trebble, M. A. (1986). A New four-parameter cubic equation of state for polar and non-polar fluids (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/19919