Kalugina N. Substantiation of the parameters of methane outflow from coal and predicting the time of formation of dangerous gas concentrations in closed volumes

The present thesis gives a theoretical analysis of methane desorption from coal into a free space and a closed volume. The developed model accounts for both methane diffusion in coal blocks and its filtration through the system of pores and cracks. A system of equations is derived and solved, which describes the dependency of methane desorption on time and coordinate, accounting for the fact that the substantial fraction of methane contained in coal is located in closed pores and in the solid solution. Experimental investigations were carried out for measuring the residual amount of methane in a coal sample. The experimental technique was based on the temporal dependency of the parameters of nuclear magnetic resonance spectra occurring on the 1H hydrogen nuclei, which enter methane sorbed by coal. Kinetics of methane escape from black coal by means of desorption into a vacuumed vessel of a fixed volume was studied. A relationship was established for the time of reaching the dangerous methane concentration, depending on the parameters of the mined coal - methane system and the technological char-acteristics.