Effects of Water Soluble Guest on Clathrate Hydrate Crystal Growth

This study reports on the visual observations of the crystal growth behavior and the crystal morphology of clathrate hydrate in liquid water presaturated with the tetrahydropyran (THP) and the methane gas. THP is the partially water soluble guest substance. It was observed that the crystal growth behavior of the hydrate in methane + THP + water system greatly changed compared to those in methane + water system, and also those in the mixed gas + water soluble ionic guest substance + water system. The hydrate was initially formed at the water – THP interface. The formed hydrate was grew to a certain size and then detached from the water ‐ THP interface. The water – THP interface was maintained and then the hydrate formation was continually repeated.