Influence of modified kaoline inhibitor on the explosion suppression pressure of the methane coal dust mixture

Gas and coal dust explosion accidents have seriously affected the safety of coal mine production,resulting in a large number of production losses and casualties. The research and development of explosion suppressants that can be used in complex environments such as high humidity and low temperature in coal mines has become a difficulty and hot research topic. In order to develop a novel type of modified kaolin methanecoal dust explosion inhibitor,three modified kaolin explosion inhibitors were prepared using the intercalation modification method,and the thermal stability of the samples was analyzed by thermogravimetric analysis,scanning electron microscopy,and infrared mass spectrometry. Surface structure and functional group changes were studied. A sample of Chongqing Nantong coal was selected,and the coal sample was sieved through a standard sieve. The particle size distribution and surface morphology of the coal powder were observed by particle size scanning and scanning electron microscope. The 20 L spherical explosion system was used to study the inhibitor’s characteristics of suppressing coal dust and gas explosions. The effects of different types and different concentrations of modified kaolin inhibitors on explosion overpressure,pressure rise rate,and time to peak pressure were explored. The results of powder characterization and explosion suppression data were used to analyze the explosion suppression mechanism of gas and coal dust explosion under the suppression effect of modified kaolin. The results show that the modified kaolin anti explosion agent has the dual antiexplosion effects of kaolin and intercalated particles,and improves the agglomeration of kaolin. At the same time,the ammonium sulfamate particles enhance the pyrolysis and explosion suppression properties of kaolin. The suppression performance of the methanecoal dust composite explosion is obviously better than that of the powder before modification,and the explosion suppression effect increases with the increase of the inhibitor concentration,and there is a critical concentration. The experiment shows that when the ratio of modified kaolin to coal dust is 2∶3,and the volume concentration is 0.175 g/L,the maximum explosion pressure drop reaches 32.6%,the peak explosion time is delayed by 0.45 s.The explosion suppression effect is best.