Azeotropic points with relative volatility-prediction and calculation

Azeotropic points with relative volatility-prediction and calculation

Saida FedaliHakim Madani 

Department of Mechanics, Faculty of Technology, Laboratory of Studies of the Industrial Energy Systems (LESEI), University of Batna, Algeria

Corresponding Author Email:
31 March 2017
| Citation



In this study, we predict the locus of azeotropes for binary mixtures by using the relative volatility is presented. A simple method is used in binary mixtures: At first we applied the method which is based on experimental data and then we evaluated by thermodynamic model. The model composed:

• Peng-Robinson equation of state

• Mathias-Copeman alpha function

• Wong-Sandler mixing rules

• NRTL model

1,1-difluoroethane (R152a) + n-butane (R600) , carbon dioxide (R744) + 1,1-difluoroethane (R152a) and 1,1,1,2-Tétrafluoroéthane (R134a) + 1,1-difluoroethane (R152a) are the binary mixtures used in this work. The results confirm that there is a good agreement between the predicted values and the experimental data and the relative error does not exceed 1% for the molar fraction and 0.5% for the pressure. In conclusion, this method is considered able to predict the azeotropic location.


Equation of State, Mixing Rules, Excess Free Energy, Azeotrope, Relative Volatility.

1. Introduction
2. Methods
3. Results
4. Discussion
5. Conclusion

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