Natural gas hydrates, NGH, are crystalline solids composed of water and natural gas where individual gas molecules exist within cages of water molecules, CH4.nH2O where n≥5.75. NGH can contain up to 160m3 of methane per 1 m3 of hydrate. Hydrate technology development has focused on using gas hydrates to convert gas to a solid (GtS) to transport natural gas to market as a low cost solution to managing associated gas in regions lacking in gas infrastructure and/or market. There could be possibilities for NGH for transport of natural gas from Trinidad to the Caribbean Islands at volumes much less than those normally considered for LNG, but still commercial to the whole transport chain from producer to consumer.

Compared to alternative technologies such as LNG and gas to liquids, GtS hydrates conversion is relatively simple, low cost and does not require complex processes or extremes of pressure or temperature. It can be small-scale, modular and particularly appropriate for offshore associated gas applications. Put simply, the hydrate production concept amounts to adding water to natural gas and ‘stirring'. However, a comprehensive understanding of hydrate behaviour is necessary to design the technology for transoceanic gas transportation.

This paper describes a hydrate slurry production process and its integration into a system for delivering gas for small scale utilities in regions of the world that lack gas pipeline infrastructure. In particular, we discuss the market potential of gas transport by hydrate, present some laboratory and pilot scale studies of results on the stability of hydrates produced in a continuous stirred tank reactor, and consider the implications of these results on the process design and overall economics and the challenges to be met before the technology can be commercialised.

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