Experimental Study on the Ignition Sensitivity and Explosion Severity of Different Ranks of Coal Dust

Junfeng Wang,Xiangbao Meng,Bo Liu,Yansong Zhang,Haiyan Chen

doi:10.1155/2019/2763907

Junfeng Wang, Xiangbao Meng + Show 3 more

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https://doi.org/10.1155/2019/2763907

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Abstract

This study is conducted to examine the ignition sensitivity and explosion severity differences among different ranks of coal dust and reveal the causes underlying these differences. A G–G furnace, a Hartmann tube, and a 20 L explosion tank are used to test MIT, MIE, Pmax, (dp/dt)max, and other parameters of three different ranks of coal dust. SEM analysis is carried out on the coal dust before and after explosion to compare and trace their microstructure changes. The results indicate that the lower the rank of the coal, the more likely the dust cloud to be ignited, the faster the explosion flame propagated, and the greater the explosion severity. The main drivers behind the ignition sensitivity and explosion severity differences among different ranks of coal dust are the volatile content and pyrolytic property of the coal.

Highlights

Coal is a conventional energy source with the highest reserve and the widest distribution in the world and one of the most important energy supplies across the globe [1]
Ignition occurs to dust clouds because when dust particles are exposed to an amount of external energy, they will be pyrolitically devolatilized first; when the combustible volatile gases have arrived at a level of concentration, they will be ignited and will heat the surrounding dust particles, causing them to pyrolyze and burn
Conclusions e MITand MIE of three different ranks of coal dust were measured with a G–G furnace. e result indicated that higher ranks of coal have a higher MIT and MIE and the dust cloud is less readily ignited. is should be attributable to the different volatile contents and pyrolysis properties among different ranks of coal sample. e coal sample that has a high volatile content and is pyrolyzed has a lower MIT and MIE, the dust cloud is more readily ignited and flames developed more rapidly at the beginning of explosion

Summary

Introduction

Coal is a conventional energy source with the highest reserve and the widest distribution in the world and one of the most important energy supplies across the globe [1]. E application of coal mining machinery in mining areas is more and more extensive [2, 3]. In semiclosed or closed spaces, coal dust tends to form dust clouds which, once exposed to ignition sources (electric sparks, open flames, or high-temperature heat sources), would explode and produce destructive shock waves which would raise the surrounding deposited coal dust and trigger a secondary explosion. Coal dust explosion is generally highly destructive, since the explosion shock waves, burning flames, and high temperatures can lead to massive casualties and property damages [5]. For this reason, coal dust explosion studies have always been a highlight in the academic world

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