Explosion suppressing effects of Mg(OH)₂/NH₄H₂PO₄ compound powders on the methane explosion and its microscopic mechanism about capturing intermediate products

The explosion suppression effects and mechanism of Mg(OH)₂/NH₄H₂PO₄ composite powders are crucial for the prevention and control of methane explosions. Explosion suppression experiments with different concentrations and mass ratios of Mg(OH)₂/NH₄H₂PO₄ were carried out. The explosion suppression mechanism was obtained by coupled analysis of the explosive characteristics, spectral properties and thermogravimetric–differential scanning calorimetry. Under the inhibitory effect of the compound powders with a ratio of 20:80 and a concentration of 520 g/m³, the P_max, T_max, and v_max of methane explosion are the lowest. Indicating that compound powders can effectively suppress methane explosion. Through the coupling analysis of the explosion characteristics and the spectral properties of methane explosion, it was found that P, T, and v of methane explosion and relative spectral intensity of the intermediate products were all positively correlated. The process of inhibiting was analyzed from a microscopic perspective, it was found that Mg(OH)₂ was noted to exhibit physical adsorption properties for H·, O·, and OH·. The thermal decomposition products of Mg(OH)₂ and NH₄H₂PO₄ also captured relevant free radicals during the methane explosion to achieve chemical inhibition. H₃PO₄, HPO₂, PO₂, and NH₃ captured H·, OH·, and CH₃·, whereas NH₂· competed with O₂ to interrupt the methane explosion chain reaction. This research provides a scientific basis for adopting effective explosion prevention and suppression measures on-site, developing of an automatic flameproof system with the function of triggering optical elements and diagnosing high temperature flame, and popularizing and applying new type of explosion suppressor and supporting explosion suppressor equipment.