Explosion suppression efficiency of gaseous phlegmatizing agents in suppressing outbreaks of methane-air mixture in the gas transmission system of coal mines

The challenge of methane emission management in coal mines is considered. Methane extraction is shown for all the stages of mine development. The gas transmission system is identified as the most important element of safety of operation of degasification systems of coal mines. The issue of the methane-air mixture phlegmatization is considered depending on the thermo-physical properties of the phlegmatizers. The occurrence mechanism of the ignition pulse and its possible routes are described. A method is suggested to prevent explosions by phlegmatization of the medium with gaseous substances or their vapors. A mathematical model of this process is presented. Results of the full-scale tests of the methane-air mixture phlegmatization using gaseous nitrogen are given. The value of critical oxygen content is specified. The proposed approach makes it possible to reduce the nitrogen consumption in phlegmatization of the explosive methane-air mixture by 15-26%.