Study on explosion suppression of coal dust with different particle size by shell powder and NaHCO3.

[Display omitted] • Shell powder is more effective in suppressing coarse coal dust. • NaHCO 3 exhibits better than shell powder in inhibiting fine pulverized coal. • "global-small scale" and "local-large scale" suppression mechanisms are proposed. In order to improve the pertinence of coal dust explosion suppression technology, a 20 L spherical explosion characteristic test system and a dust minimum ignition energy test device were used to study the suppression differences of different particle sizes of coal dust with inert and active explosion suppressants. The results showed that the inert explosion suppressant was more effective in suppressing coarse coal dust, while the active explosion suppressant was more advantageous in suppressing fine coal dust explosion. The maximum pressure (P max) and maximum pressure rise rate ((d P /dt) max)) of 30 wt% NaHCO 3 in the suppression of fine coal explosion decreased by 26.8% and 54.2%, respectively, compared with that of raw coal, while the suppression data of NaHCO 3 to coarse coal was 25% and 30.8%. Kinetic analysis showed that NaHCO 3 was better than shell powder (SP) in inhibiting fine coal and the activation energy reached 82.76 kJ/mol which increased by 94.5%. However, the activation energy of coarse coal increased more significantly under SP suppression. The global -small scale and local-large scale explosion suppression mechanisms of coal dust with different particle sizes were put forward. This study can provide scientific theoretical guidance for targeted coal dust explosion suppression. [ABSTRACT FROM AUTHOR]