FORMATION OF METHANE HYDRATES IN NATURAL CARBON

The results of experimental studies of the formation of methane gas hydrates in the interior of natural coal are presented. In gas hydrates, molecules of hydrophobic gases are built in the cavity of the crystal lattice created by water molecules. Gas hydrates can produce methane, light hydrocarbon gases, carbon dioxide, nitrogen, etc., as well as their mixtures. At the same time, up to 170 gas volumes are released from one volume of gas hydrates during decomposition. Gas hydrates are common in nature, they were found in the permafrost zone, as well as at the bottom of cold seas and oceans. At present, technologies for extraction of hydrocarbon gases from gas-hydrate deposits are being designed. The zoneof stable existence of gas hydrates in polar latitudes reaches a thickness of 400-700 meters. Gas hydrates are formed in the presence of water, gas, high pressure, not very high temperature, as well as a suitable collector. Thermobaric conditions of occurrence of the majority of coal seams of the Pechersky basin and a part of coal seams of Kuzbass correspond to conditions of stable existence of gas hydrates of methane. In the present work, the possibility of forming gas hydrates from water in a sorption bond with the surface of coal has been studied. It is established that the decomposition points of methane gas hydrates in natural coal are close to the decomposition points of methane gas hydrates formed from macroscopic amounts of water. The amount of gas hydrates formed in natural coals under specified conditions is experimentally determined. It is established that not all sorbed water is in forms from which the formation of gas hydrates is possible. NMR studies of water in a coal substance, as well as calorimetric analysis. The presence of strongly bound water in a natural carbon, which is incapable of forming crystalline compounds, is shown.