煤田火区煤阴燃特性及治理研究

发布时间：2018-03-19 08:18

  本文选题：阴燃特性　切入点：火风压　出处：《中国矿业大学》2017年硕士论文　论文类型：学位论文

【摘要】：煤火燃烧持续时间长、燃烧面积大,一些灭火措施至今仍然没能有效熄灭大面积的煤田火灾,为探究煤火燃烧持续时间长且难以熄灭的原因,根据地下煤火的燃烧表现出的阴燃现象,论文尝试将阴燃的研究理论和方法应用到煤的燃烧过程中。研究发现煤火的持续燃烧是煤阴燃传播的结果,煤火难以熄灭与煤阴燃特性有关,因此提出切断煤阴燃传播治理煤火的思路。基于此,构建了煤阴燃实验平台,对煤阴燃的燃烧特性进行研究,应用到了露天矿煤火的治理案例当中,取得的主要成果和结论如下:风流速率对煤的燃烧速率、阴燃传播速率和温度影响较大。一定范围内风流速率越大,燃烧速率越大,阴燃传播越快,最高温度越高。竖直阴燃条件下煤的燃烧速率随着风流速率线性增加。当风流速率位于0.074~1.48m/min时,阴燃传播速率位于31.03~213.3mm/h,阴燃的温度范围在450℃~1050℃,煤可以以一定风量下在500℃以下维持阴燃。当风量从2m3/h降低到0.1m3/h时,总阴燃时间从11.4h增加到146.3h,总阴燃时间随着风量的减弱呈指数型增长。煤维持阴燃的最低供风速率在0.009~0.013m/min范围之间。煤田火区治理实践中,常规性的堵漏窒息措施难以保证把漏风速率控制在0.009m/min以下。正是因为煤火的阴燃在很低的漏风速率下也能维持,才导致以堵漏窒息为主的治理措施失效,造成煤火难以熄灭。火风压是煤火持续阴燃的供氧动力,是其阴燃的主要特性之一。归纳总结了煤火的四种供氧通道,建立了煤火的火风压模型,计算结果表明深度为30m的煤火阴燃区域在最低供风速率0.009~0.013m/min条件下所产生的火风压为0.1~0.15Pa。该模型可用来评价火区堵漏效果,即如果堵漏后实测出火风压远远高于0.1~0.15Pa时,说明火区没有完全熄灭,有待进一步采取堵漏措施。露天矿煤火治理应以火区降温为主、堵漏窒息为辅来达到切断煤阴燃传播的目的。以东露天矿火区治理为例,分析了露天矿煤火的成因和特性,优选出治理露天矿煤火的治理技术,建立了露天矿煤火的传热模型,确定了灭火介质所需量是该理论模型计算量一半的估算结果。现场实践表明:泡沫相对于注水、注浆技术具有水利用效率最高、降温效果时间最长的优势;泡沫的灭火降温效果显著,相对而言更能有效阻止露天矿煤火的发展蔓延。
[Abstract]:The burning time of coal fire is long and the burning area is large. Some fire extinguishing measures have not been able to extinguish the large area of coal field fire effectively so far. In order to explore the reason why the burning time of coal fire is long and difficult to extinguish, According to the phenomenon of smouldering in underground coal combustion, this paper attempts to apply the theory and method of smouldering to the combustion process of coal. It is found that the continuous combustion of coal fire is the result of coal smoldering propagation. The difficult extinguishing of coal fire is related to the characteristics of coal smouldering. Therefore, the idea of cutting off the propagation of coal smouldering and treating coal fire is put forward. Based on this, an experimental platform for coal smouldering is constructed to study the combustion characteristics of coal smouldering. The main results and conclusions are as follows: the air flow rate has great influence on coal combustion rate, smoldering propagation rate and temperature. The larger the air flow rate is, the greater the combustion rate is in a certain range. The faster the smoldering propagation is, the higher the maximum temperature is. The combustion rate of coal increases linearly with the air flow rate under vertical smoldering conditions. When the air flow rate is 0.074 ~ 1.48 m / min, the smoldering rate is 31.03 ~ 213.3 mm / h, and the temperature range of smoldering is 450 鈩，

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