| 초록 |
Natural gas hydrates are nonstoichiometric compounds that formed at high pressure and low temperature and have a large potential of future clean energy resources. Some gas hydrates show meta-stability, which means gas hydrates are not dissociated below thermodynamic equilibrium curves. This unusual behavior is called self-preservation effect. Recently, it was revealed that the presence of montmorillonite (MMT), one of marine clay components, can affect cage occupancy of CH4 hydrate. However, the dissociation behavior has not been well studied. In this study, the effects of Na-saturated MMT on the thermodynamic equilibria, guest distributions, and dissociation behaviors of CH4 hydrates were examined with different MMT concentrations (0, 10, and 50 wt%). The cage occupancy of CH4 hydrates with MMT were analyzed using 13C NMR. In addition, the hydrate dissociation behaviors in the presence of MMT were observed by temperature-dependent powder X-ray diffraction patterns. The results demonstrated that Na-MMT does not affect H-L–V equilibria of CH4 hydrates, but can contribute to retarding the dissociation of CH4 hydrates below 273.15 K. |
