Gas explosion suppression by ammonium dihydrogen phosphate-modified dry water powder

Dry water materials have high-efficiency and green characteristics. Dry water powder was prepared, and explosion suppression experiments were conducted using a flame propagation experimental system. The influence of dry water powder quality and MAP concentration on gas explosion characteristics were investigated. According to the experimental results, compared with unmodified dry water powder, MAP-modified dry water powder had an 11.66% higher moisture retention rate, 14.27% lower thermogravimetric mass loss, and 8.43% lower maximum mass loss rate. When the dry water powder concentration exceeded 260 g/m3, the gas explosion inhibition effects increased with the dry water powder concentration. When the MAP concentration was 0%–20%, the gas explosion suppression effect increased and then decreased as the MAP concentration increased. When the MAP concentration was 10%, the optimal explosion suppression effect was achieved. Adding 520 g/m3 MAP (10 mass%)–modified dry water powder reduced the maximum flame temperature at thermocouples #1 and #2 by 39.11% and 43.95%, respectively, and Vmax decreased by 20.63%. The MAP-modified dry water powder had a physical–chemical inhibition mechanism, and the gas explosion suppression performance was substantially enhanced. Thus, a new high-efficiency gas explosion suppression material was obtained. This research highlighted the importance of coal mine safety in relation to gas explosions and supported dry water material use in coal mines.