Dissociation Behavior of Pellet-Shaped Methane Hydrate in Ethylene Glycol and Silicone Oil. Part 1:  Dissociation above Ice Point

The dissociation behavior of a pellet-shaped methane gas hydrate in ethylene glycol and silicone oil above the ice point (273.15 K) has been investigated experimentally, assuming the transportation or storage systems of natural gas using gas hydrates. Pellet-shaped hydrate samples were prepared using artificial fine methane hydrate powder. These pellets were soaked in ethylene glycol or silicone oil in a high-pressure optical vessel, and the dissociation reaction was induced by decreasing system pressure. Dissociation rate was measured under different isothermal−isobaric conditions, and the reaction surface was visually observed. The obtained dissociation rates were discussed with a mathematical model based on one-dimensional thermal conduction. From these approaches, some characteristic aspects of the dissociation behavior of a methane hydrate pellet in ethylene glycol and silicone oil, which are not observed in a simple system, are discussed. The dissociation behavior below the ice point will be treated in our subsequent study.