Effects of CaCl2, Al(OH)3, And NH4H2PO4 on the Explosion Intensity of Pulverized Coal

Abstract

ABSTRACT Herein, the ability of three explosion inhibitors (Al(OH)3, CaCl2, and NH4H2PO4) to prevent the occurrence of coal-dust explosions was compared at mass fractions of 30 wt% and 50 wt%. The effects of the three explosion inhibitors on the parameters characterizing the explosion intensity of pulverized coal, such as the maximum explosion pressure, pressure rise rate caused by the explosion, and the explosion index, were investigated. The results demonstrate that with increasing mass fractions of CaCl2 and NH4H2PO4, the explosion intensity of pulverized coal decreases. Notably, an increase in the mass fraction of Al(OH)3 did not reduce the explosion intensity. Furthermore, 50 wt% NH4H2PO4 content considerably decreased the values of both the maximum explosion pressure during a single explosion (Pex) and the maximum rate of explosion pressure rise in a single dust explosion experiment [(dp/dt)ex]. The maximum decrease in Pex after adding NH4H2PO4 was observed to be 62.79%, which is 35.87% and 47.70% higher than that obtained after adding CaCl2 and Al(OH)3, respectively. Furthermore, the maximum decrease in (dp/dt)ex after adding NH4H2PO4 when compared with the pulverized coal was 93.07%, which is 10.23% and 45.51% higher than that obtained after adding CaCl2 and Al(OH)3, respectively. Therefore, the order of the explosion suppression performance was as follows: NH4H2PO4 > CaCl2 > Al(OH)3.