不同堆积厚度下煤粉自燃预测研究

Prediction of high volatile coal powder spontaneous combustion

为研究烟煤煤粉在不同堆积形状、堆积厚度下煤粉自燃现象以及自燃过程中临界温度与煤粉堆积厚度的关系,揭示了煤粉不同堆积形状、厚度下的自燃机理。设计了温度为100~140℃下煤粉的氧化放热实验,探讨了以金属网篮交叉法为主的煤粉自燃厚度计算过程,研究了不同环境温度下的煤粉自燃温度和厚度地变化关系。以Frank-Kamenetskii理论模型和氧化动力学模型为研究基础,推导出煤粉自燃临界厚度公式,结合自主搭建实验台,最大限度地模拟实际环境中煤粉的氧化升温过程。结果表明,在生产过程中收尘器布袋积粉厚度大于20 cm时,容易发生煤粉自燃;煤粉堆放环境温度大于30℃时,不宜采用两层堆放方式。该测试方法简单准确,可靠性高,可为其他温度下的煤粉自燃提供很好的实验手段,也为现场煤粉自燃防治提供理论支撑。

In order to examine the spontaneous combustion of high volatile coal powder in Shenfu coalfield and the relationship between critical temperature and thickness of coal powder during spontaneous combustion,the critical thickness of coal powder under different piled shapes was revealed.In this paper,the oxidation exothermic experiment of coal powder at temperature of 100~140℃was designed.Based on the comparative analysis of intersection temperature and heating rate,combined with the apparent activation energy and reaction calorific value of coal powder,the metal basket cross method was discussed.With the spontaneous combustion thickness of coal powder calculated,the relationship between the spontaneous combustion temperature and thickness of coal powder under different environmental temperatures was studied.By using Frank-Kamenetskii theoretical model and oxidation kinetics model,the formula of the critical thickness of spontaneous combustion of coal powder was deduced,and the experimental experiment was built independently to simulate the oxidative heating process of coal powder in the actual environment.The results show that coal powder spontaneous combustion is easy to occur when the thickness of the dust collector bag is more than 20 cm in the production process.When the coal powder product stacking temperature is greater than 30℃,it is not suitable to adopt two-layer stacking method.The test method is accurate and simple.It is a good experimental method for the spontaneous combustion of pulverized coal at other temperatures,which can provide theoretical support for the site of coal powder spontaneous combustion and improve the fire-protection effect and reduce the cost of prevention.