Self-preservation effect modelling in hydrate systems using Lattice Dynamic methods

The thermodynamic properties of the carbon dioxide clathrate hydrate as well as hexagonal ice Ih have been calculated using Quasiharmonic Lattice Dynamic framework in connection with Molecular Dynamic methods in order to show the existence of the self-preservation effect in the carbon dioxide hydrates. The statistical thermodynamics theory has been applied to calculate the thermal expansion coefficients for hydrate and ice systems. The calculations clearly show that because the thermal expansion of the hydrate phase is limited by the thermal expansion of ice it is possible to keep the hydrate in a stable region within the phase diagram. The differences in thermal expansion should lead to the self-preservation effect with the application of additional pressure on the hydrate phase. This effect allows using the self-preservation effect for the storage and transportation of gas in the hydrate form.