An improved clapeyron model for predicting high - Pressure gas hydrate phase equilibria
Résumé
Prediction of gas hydrate phase diagram for the liquid water - hydrate - liquid hydrate former region is a challenge considering this diagram at these conditions is strong function of temperature. The Clapeyron model is traditionally used for this purpose. However, the conventional Clapeyron model does not take into account the effect of pressure on the hydrate molar volume as well as the heat of dissolution of hydrate former in water and therefore cannot predict satisfactorily gas hydrate phase diagram. In this work, the conventional Clapeyron model is extended to take into account the aforementioned factors as well as the change in the slope of the pressure - temperature hydrate phase diagram when increasing the temperature. Three hydrate formers: carbon dioxide, hydrogen sulfide and ethane, are studied. It is found that the effect of these factors on the prediction of the gas hydrate phase diagram is not negligible.
Mots clés
Clapeyron model
Gas hydrates
Heat of dissolution
Hydrate molar volume
Effect of pressure
Heat of dissociation
High pressure gas
Hydrate phase
Liquid water
Molar volumes
Carbon dioxide
Dissociation
Dissolution
Ethane
Forecasting
Gases
Hydration
Hydrogen sulfide
Liquids
Phase diagrams
Phase equilibria
Pressure effects
Volume measurement