Spectroscopic Explanation of Metastablity in Gas Hydrate Formation

摘要

Clathrate hydrates have been researched for their various applicationsrnsuch as natural gas hydrate production, energy gas storage, carbonrncapture and sequestration, and synthesis and fabrication of versatilernenergy devices. The structure H(sH) hydrate is important in the oilrnindustry because its large cage(5~(12)6~8) can accommodate largerrnmolecules found in crude oil regions that cannot occupy the large cagesrnof structure I(sI) (5~(12)6~2) and structure II(sII) (5~(12)6~4) hydrates. However,rnthere is only limited research of sH hydrate, contrary to sI and sII. Thernmajor difficulties of understanding of sH hydrate are that 1) sH can bernformed only in the presence of large guest molecules (LGMs) and 2)rnmost of the LGMs are insoluble or sparingly soluble in water. Also,rnthere have been no reports on sI-sII-sH whole-phase-behaviour. Thernaforementioned barriers can be overcome by exploiting hydrophilicrnLGMs such as hexamethyleneimine(HMI). These highly water-solublernLGMs can create a homogeneous solution, which guarantees uniformrnhydrate phases. Therefore, the kinetic behaviour of gas hydrate phasesrncan be compared using HMI at a laboratory scale.