Research of Thermodynamic Conditions for Gas Hydrates Formation from Methane in the Coal Mines

Abstract

This article is focused on solving the problem of power supply for the mining and industrial regions of Ukraine. This problem is caused by a significant import dependence on natural gas, the lack of efficient technologies in the integrated development of the energy resources of gas-coal deposits and the deterioration of social and economic, as well as environmental conditions in mining regions. As a promising direction for solving the problem of rational use of methane from coal mines and reducing the hazardous gas emissions into the atmosphere, the implementation of gas hydrate technologies into the technological complex of a coal mine has been proposed. The Clausius-Clapeyron equation has been improved for the conditions of gas hydrates formation, which considers the presence of an excess in non-equilibrium defects and is supplemented, taking into account the thermal effect of phase transformations, with all the time positive thermal effect of the defects relaxation. It has been revealed that one can intentionally control the relaxation energy of defects by the thermodynamic stimulus of phase transformations in the process of hydrate formation. The experimental dependences have been determined of the change in hydrate accumulation on the time of hydrate formation, with the methane hydrates production and taking into account the parameters of pressure and temperature. It has been revealed that the maximum fast time of hydrate formation at T = 1°C and P = 10 MPa is the time which amounts to 2.5 hours. The experimental dependences have been determined of the gas hydrates formation out of a methane-air mixture of degassing holes, on the methane concentration, on pressure and temperature parameters. It has been determined that the greater the methane concentration in the mixture, the greater must be the pressure in the system for the gas hydrates formation.