RESUMEN
The ignition and explosion processes of suspended coal dust clouds and their suppression characteristics are important aspects of dust prevention and control. To understand the ignition temperature and explosion pressure of coal dust clouds, as well as the inhibitory effect of explosion suppressants, experimental tests are conducted. The study found that during the ignition process of coal dust clouds, the optimal dust spray pressure is 20 kPa, because coal dust clouds are more likely to ignite under this condition. When the mass concentration of coal dust cloud is 500 g m-3, the maximum pressure and maximum pressure rise rate are both the highest. When Al(OH)3 is mixed with coal dust and the mass percentage is 60%, the coal dust cloud can still be ignited. When KH2PO4 is mixed with coal dust, the upper limit of the test temperature is reached when the percentage of mixture is 55%. When NH4H2PO4 is mixed with coal dust and the mass percentage is greater than 40%, the coal dust cloud can't be ignited anymore. The suppression effect of mixing Al(OH)3 and NH4H2PO4 is not as good as that of mixing KH2PO4 and NH4H2PO4.
RESUMEN
To discuss the inhibition of long flame coal dust explosion pressure, NaHCO3, KHCO3, and NH4H2PO4 are selected as explosion suppression dust for explosion pressure tests under different conditions. The results show that when 25-38 and 38-45 µm coal dust are mixed in 1:1 ratio, the maximum explosion pressure is the largest, the maximum pressure is 0.79 MPa, and the maximum pressure rise rate is 74.89 MPa·s-1. The suppression dusts have good inhibition effect on explosion, the order of inhibition is NaHCO3, KHCO3, and NH4H2PO4 from the smallest to the largest. With the reduction of particle size of NH4H2PO4, its inhibition effect on explosion pressure is increasing, because more NH4H2PO4 particles move around coal dust particles, blocking the heat transfer and kinetic energy exchange. The above three suppression dust and their suppression methods can provide important data for dust prevention and control and have certain reference significance for carrying out explosion suppression work.