氧化煤尘的爆炸特性及其变化规律

Explosion Characteristics and variation of oxidized coal dust

氧化煤是指经历过升温又降温过程的煤体,在矿井火区启封、分层开采、遗煤复采等区域一直广泛存在,这些区域煤炭开发利用产生的煤尘为氧化煤尘。由于煤体发生了不同程度的氧化,内部结构受到影响,所产生氧化煤尘的爆炸特性发生改变。针对不粘煤样,采用程序升温箱对样品进行了不同温度(25、75、115℃)的预处理,探讨氧化煤尘爆炸特性在不同变量(氧化煤尘云浓度、氧化煤尘粒径)条件下的变化规律。结果表明:氧化煤尘爆炸过程可划分为4个阶段,分别为初始负压阶段、高压喷尘阶段、爆炸升压阶段和压力衰减阶段;氧化煤尘爆炸特性与煤尘云浓度符合二次多项式规律,随浓度增大而先升后降,T_(25)、T_(75)和T_(115)煤尘最优煤尘云浓度集中在300 g/m^(3)和200 g/m^(3);在煤尘云浓度一定时,氧化煤尘最大爆炸压力值随粒径增大而减小。

Oxidized coal is a coal body that has undergone the process of warming up and cooling down,and has been widely used in mine fire area start-up,stratified mining,and re-mining of residual coal,etc.The coal dust generated from coal development and utilization in these areas is oxidized coal dust.Due to the different degrees of oxidation of the coal body,the internal structure is affected,and the explosion characteristics of the resulting oxidized coal dust are changed.For the non-stick coal,this paper used a programmed heating chamber to pretreat the samples at different temperatures(25℃,75℃and 115℃)to explore the change in the explosion characteristics of the oxidized coal dust under the conditions of different variables(oxidized coal dust cloud concentration,oxidized coal dust particle size).The results show that the explosion process of oxidized coal dust can be divided into four stages,namely,the initial negative pressure stage,high pressure dust injection stage,explosion boost stage and pressure decay stage;the explosion characteristics of oxidized coal dust and coal dust concentration conform to the quadratic polynomial law,which increases and then decreases with increasing concentration,and the optimal coal dust concentrations of T_(25),T_(75)and T_(115)coal dust are concentrated at 300 g/m^(3)and 200 g/m^(3);in the coal dust cloud concentration is constant,the maximum explosion pressure value of oxidized coal dust decreases with the increase of particle size.