Study on the inhibitory property and mechanism of inert powder on dust explosion flame of oil shale

Abstract

In order to study the inhibitory property and mechanism of inert powder on dust explosion flame in oil shale, five common inert powder and two types of oil shale were selected for the explosion flame inhibition experiment by using the dust explosion flame propagation test system. First, a high-speed camera was used to record the flame image during the inhibition of oil shale dust explosion by inert powder, and the differences in explosion flame length, minimum inerting ratio and flame morphology and structure were analyzed in detail. Then, the thermal decomposition and endothermic characteristics of the inert powder were tested by Thermogravimetric-Differential Scanning Calorimetry (TG-DSC), and the TG-DTG-DSC thermal characteristic curve of the inert powder was analyzed. Combined with the analysis of the inhibition effect of the inert powder in the preheating zone and the combustion flame zone, the inhibitory property and the mechanism of the inert powder on the oil shale dust explosion flame were systematically studied. The research results show that the inhibitory performance of inert powder to the explosion flame of two kinds of oil shale dust is ranked as: ABC dry powder ＞Al(OH)3＞Mg(OH)2＞NaHCO3＞rock powder, and their explosion inhibition performance against Huadian oil shale (HDOS) is better than that of Longkou oil shale (LKOS). In this paper, the physical model of the inhibition mechanism of inert powder on the explosion flame of oil shale dust is established and the inhibition mechanism is analyzed. Through the mechanism analysis, it is shown that the high-efficiency explosive inhibition powder should have good thermal stability (decomposition temperature around 200−400 ℃), high heat absorption, and the decomposition of intermediate products can combine with the combustion reactive radical to play a chemical inhibition effect. The research results can provide theoretical basis and basis for the design of explosion inhibition of oil shale dust and the development of explosive inhibition powder.