Gibbs ensemble Monte Carlo simulations of binary vapour–liquid–liquid equilibrium: application to n-hexane–water and ethane–ethanol systems

Abstract

Gibbs ensemble Monte Carlo (GEMC) simulations in the isochoric–isothermal (NVT) ensemble were used to simulate vapour–liquid–liquid equilibrium (VLLE) for binary n-hexane–water and ethane–ethanol mixtures. The GEMC simulation of binary VLLE data proved to be extremely difficult and that is probably the reason why the open literature is so sparse with simulations for these types of systems. The results presented in this paper are to our knowledge the first successful binary three-phase GEMC simulations of non-idealised fluid systems. This paper also shows that the isobaric–isothermal (NPT) ensemble is unsuitable for the simulation of phase equilibria of binary three-phase systems.

Keywords:

• Monte Carlo
• Gibbs ensemble
• phase equilibria

Acknowledgements

We thank the Swedish International Development Cooperation Agency (SIDA) and the National Research Foundation (NRF, South Africa) for their financial assistance. The simulations were performed on a Beowulf computer sponsored by Sparbanksstiftelsen Sjuhärad. This work is based upon research supported by the South African Research Chair Initiative of the Department of Science and Technology.