Modeling of thermodynamic properties of binary and ternary mixtures. Determination of phase diagrams

The prediction and the determination of the azeotropic point of the binary or ternary refrigerants are very important in refrigerating industry. In this task, a simple method is presented in order to predict and determine the azeotropic point. Our method employs experimental data and a thermodynamic model. trifluoroiodomethane (R13I1) in the mixture presents the possibility of inventing the azeotropic properties. The mixtures studied in this work are:  binary mixtures R600a + R1234ze, R600a + R13I1, R1234ze + R13I1 and the ternary mixture R600a + R1234ze + R13I1. The model consists of the Peng–Robinson equation of state (EoS), the Mathias–Copeman alpha function and the Wong-Sandler mixing rules involving the NRTL model. The results proved that there are a good agreement between the predicted values and the experimental data. The presented methods are able to predict the azeotropic positions in binary or ternary mixture.