Suppression characteristics of methane/coal dust explosions by active explosion suppression system in the large mining tunnel

To enhance intelligent prevention and control of methane/coal dust explosions in coal mines, the active explosion suppressor was developed. Methane/coal dust explosion suppression experiments were carried out in an 896-m mining tunnel. The suppression mechanism of NH4H2PO4 powder during methane/coal dust explosions was elucidated. The results indicated that the device effectively prevented flame propagation within a 40 m radius by propelling NH4H2PO4 powder using high-pressure nitrogen. There was a significant reduction in the intensity and destructiveness of the overpressure, with a maximum decrease of 61.43 %. The phosphorus-containing material produced by NH4H2PO4 consumed free radicals through catalytic cycles of HOPO double left right arrow PO2 and HOPO double left right arrow HPO3 double left right arrow PO(OH)(2), weakening and interrupting the reactions, and suppressing flame development. NH4H2PO4 reduced peak concentrations of CO and NO2. Guidelines for explosion suppression of CH4/coal dust explosions in large mining tunnel were presented. The findings provide technical and theoretical support for the prevention and control of methane/coal dust explosions in coal mines.