Thermodynamic Model for Prediction of Pressure – Temperature Phase Diagrams of Binary Clathrate Hydrates of Methane with Ethane, Propane, CO2, H2S and Nitrogen

Accurate knowledge of phase equilibria of clathrate hydrates of gaseous mixtures is important for various industrial applications especially in gas sepraration and storage. This work aims at developing a thermodynamic model based on equality of fugacity concept for predicting the dissociation conditions of binary clathrate hydartes of methane + ethane, methane + propane, methane + carbon dioxide, methane + hydrogen sulfide and methane + nitrogen. The van der Waals – Platteeuw theory is used to model the hydrate phase. The gas phase is modeled using the Peng-Robinson equation of state with random mixing rules. The Krichevsky-Kasarnovsky method is used to model the aqueous phase. Some selected experimental data from the literature are used for comparision with the predictions of this model and also a literature model, wich is based on equality of chemical potential concept. It is shown that our model can reliably predict the dissociation conditions of the aforementioned systems and generrally shows better predictions in comparison with the investigated literature model. Particularly, the change in hydrate structure for the methane + ethane + water and methane + propane + water systems is taken into account in our model

کلیدواژه ها:

Gas hydrate ، Thermodynamic model ، Gasesous mixtures