A New Approach to PVT Properties and Vapor Pressure Estimation from the SRK Equation of State

Soave-Redlich-Kwong (SRK) is an equation of state (EoS) that may be used to determine vapor pressure in addition to PVT properties. In this work, a dimensionless version of the SRK equation has been simplified by combining the temperature and acentric factor into a similarity variable, η. Other new dimensionless variables were defined by combining pressure and temperature into a dependent variable, Ψ, and by defining a reduced density variable, ρr’, relative to the maximum liquid density in the low temperature limit. A Taylor series expansion in the similarity variable η was used to express reduced liquid and vapor densities, compressibilities, and vapor pressure by simple polynomials. The truncation error of these series was characterized. This work resulted in a simpler method of estimating PVT properties and vapor pressure that would be predicted by the SRK equation for any substance.