Arash Kamran-Pirzaman - Chemical Engineering Department, Faculty of Engineering, Tarbiat Modarres University, Tehran, Iran
Hassan Pahlavanzadeh - Chemical Engineering Department, Faculty of Engineering, Tarbiat Modarres University, Tehran, Iran
Amir H. Mohammadi - bMINES ParisTech, CEP/TEP - Centre Énergétique et Procédés, ۳۵ Rue Saint Honoré, ۷۷۳۰۵ Fontainebleau, France

This work aims at developing a thermodynamic model for predicting pressure – temperature phase diagrams of clathrate hydrates of methane, carbone dioxide or nitrogen + tetrahydrofuran (THF) for various concentrations of THF in aqueous solution. The model is based on equality of water fugacity in the aqueous and hydrate phases. The solid solution theory of van der Waals – Platteeuw is used for calculating the fugacity of water in the hydrate phase. The UNIFAC group contribution model is used to calculate the water and THF fugacities in the aqueous phase. The Peng-Robinson equation of state is employed to calculate the gas phase fugacity. It is assumed that the gas phase is water and THF free. The results of this model are compared with some selected experimental data from the literature. Acceptable agreement between the model predictions and experimental data demonstrates its reliability.

Gas hydrate, THF, Methane, Carbone dioxide, Nitrogen, Thermodynamic model