Towards a fundamental understanding of natural gas hydrates

Gas clathrate hydrates were first identified in 1810 by Sir Humphrey Davy. However, it is believed that other scientists, including Priestley, may have observed their existence before this date. They are solid crystalline inclusion compounds consisting of polyhedral water cavities which enclathrate small gas molecules. Natural gas hydrates are important industrially because the occurrence of these solids in subsea gas pipelines presents high economic loss and ecological risks, as well as potential safety hazards to exploration and transmission personnel. On the other hand, they also have technological importance in separation processes, fuel transportation and storage. They are also a potential fuel resource because natural deposits of predominantly methane hydrate are found in permafrost and continental margins. To progress with understanding and tackling some of the technological challenges relating to natural gas hydrate formation, inhibition and decomposition one needs to develop a fundamental understanding of the molecular mechanisms involved in these processes. This fundamental understanding is also important to the broader field of inclusion chemistry. The present article focuses on the application of a range of physico-chemical techniques and approaches for gaining a fundamental understanding of natural gas hydrate formation, decomposition and inhibition. This article is complementary to other reviews in this field, which have focused more on the applied, engineering and technological aspects of clathrate hydrates.