Modification of Peng–Robinson Cubic Equation of State with Correction of the Temperature Dependency Term

Abstract

Equations of state (EoSs) have always been one the most interesting field of study for scientists and engineers, due to their extensive applications in various industries and scientific research. Accordingly, scientists have extensively studied useful modifications of the original EoSs. In this study, the temperature dependent part of the Peng–Robinson cubic equation of state is modified. The new dual parameter α-function is able reproduce the vapor pressure data accurately for a large variety of pure components. Mono-atomic and di-atomic molecules, hydrocarbons, polar and associating compounds are well represented by the Peng–Robinson–Saali equation of state with negligible deviation with experimental data. Moreover, the thermodynamic consistency test of P–T–x solubility data based on the fundamental Gibbs–Duhem equation, for binary mixtures including acid gases (CO2 and H2S)/polar and associating solvents at low and high pressure were also investigated. The proposed EoS coupled with a three-parameter binary interaction term, namely the Panagiotopoulos–Reid mixing rule, was used in order to present the PR–Saali EoS as a versatile equation for analyzing thermodynamic consistency of experimental data. Modeling processes were carried out by using MATLAB 2018a.