New Corresponding States Theory Using the Second Virial Coefficient as the Temperature Variable. Topical Report December 1982 - December 1984

摘要

A new corresponding states theory is presented that uses an approximation to the reduced second virial coefficient as its temperature variable. This new corresponding states variable, X(T(sub r)), is chosen to be a simple function of temperature, critical temperature and the Boyle temperature. Using data generated from an accurate equation of state, it is demonstrated graphically that pure component compressibility factors are universal functions of reduced volume and the new variable X(T (sub r)) over a wide range of densities. Homogeneous mixture compressibility factors are shown to be a function of X(T (sub r)) for the limited number of systems studied, however, the correlation cannot as yet be used for two-phase binary mixtures. The theory predicts that the saturation properties of pure fluids may be represented by a universal surface, called UNISAT, upon which the reduced vapor pressure and reduced saturated gaseous and liquid densities are universal functions of X(T (sub r)). Empirical equations based on UNISAT, called UNISAT2, are presented and shown to yield results for over forty compounds, including hydrocarbons, alcohols, acids, other organics and inorganics, which are as good as, or better than, those obtained from generalized equations available in the literature. Finally, surface tensions of non-polar and non-associating polar fluids are found to correlate well with X(T (sub r)).