The characteristics and mechanism of core-shell structure fly ash/KH2PO4 composite inhibitor in suppressing coal dust explosions

Abstract

Coal dust is highly susceptible to explosions when exposed to an ignition source, leading to significant casualties and property damage. To develop a more effective coal dust suppressant, a composite inhibitor consisting of fly ash (FA) and KH₂PO₄ was prepared using a planetary ball mill. The suppression characteristics of the FA/KH₂PO₄ composite were investigated using a 20 L spherical explosion test system and FTIR analysis. Kinetic modeling of the FA/KH₂PO₄ inhibition of explosions was performed in conjunction with Chemkin software. The results indicated that a 1:1 ratio of FA to KH₂PO₄ provided optimal suppression. At a dosage of 55 wt%, complete suppression was achieved. The FA/KH₂PO₄ composite inhibited the oxidation of coal by reducing the reaction rate of radicals originating from the preheating zone. KH₂PO₄ suppresses explosions by capturing active radicals and inhibiting the formation of key functional groups, while FA contributes to suppression through the creation of physical barriers and radical adsorption. This combination exhibits a synergistic effect in suppressing coal dust explosions.