Study of methane hydrate dissociation under subzero temperatures

The use of cryolithozone resources is currently one of the priority issues on the agenda of scientific and technological and, consequently, economic development of the Russian Federation. The available research results confirm the possibility of using cryogenic processes and phenomena in engineering, agriculture, conservation of biological diversity and a number of other areas, such as, for example, for storing gas in a solid hydrate state. This paper presents the results of studies of methane hydrate dissociation obtained in systems with the presence of promoting additives in order to determine the conditions and efficiency of gas storage in a solid hydrate state. Dissociation of gas hydrates formed from liquid solutions or dispersed systems was carried out by experimental methods using a high-pressure reactor in the temperature range of 263–268 K, i.e. close to the temperatures of permafrost occurrence. Thus, it was shown that methane hydrates formed from liquid solutions of surfactants - soy lecithin and SDS, has high porosity, as a result of which it is practically incapable of self-preservation and cannot be used in the implementation of gas hydrate technologies for gas storage. At the same time, the addition of water-soluble polymer polyvinyl alcohol in a concentration of 0.3 wt.% leads to the growth of a denser methane hydrate capable of self-preservation at a temperature of 268 K. The data obtained in the work can be used in the development of gas hydrate technologies for storing natural gas in a solid hydrate state.