硅化作用对煤低温氧化特性参数的影响规律

    The influence of silicification on coal low-temperature oxidation characteristic parameters

    • 摘要: 为研究硅化作用对煤低温氧化特性参数的影响,采用电镜扫描技术,分别对硅化煤与非硅化煤进行扫描电镜试验,观察其孔隙结构的差异;并利用煤自燃程序升温试验系统进行试验测试,得到不同温度下2种煤样低温氧化特征与标志气体变化规律,在此基础上分析其在低温氧化进程中不同温度下的耗氧速率。结果表明:硅化作用使煤体孔隙变大,比表面积增加,一方面有利于气体在煤体中赋存,另一方面煤体与氧气的复合反应更充分,硅化煤更容易氧化自燃;硅化煤氧化过程中生成的标志气体体积分数始终高于非硅化煤,且在温度升高至110 ℃以后,2种煤样气体产物体积分数差异逐渐变大,可能是因为硅化作用使煤体及其分子结构产生物理化学变化,导致硅化煤更容易氧化裂解;硅化煤的耗氧速率和CO生成速率始终高于非硅化煤,说明硅化作用增强了煤的低温氧化特性。

       

      Abstract: In order to study the effect of silicification on low temperature oxidation characteristics of coal, scanning electron microscopy(SEM) was used to observe the difference of pore structure between silicified coal and non-silicified coal; the temperature programmed test system of spontaneous combustion of coal was used to test the characteristics of low temperature oxidation of two coal samples at different temperatures and the variation rule of indicator gas. On this basis, the oxygen consumption rate at different temperatures in the process of low temperature oxidation was analyzed. The results show that silicification enlarges the pores and increases the specific surface area of coal, on the one hand, it is beneficial to the occurrence of gas in coal, on the other hand, the composite reaction between coal and oxygen is more sufficient, and the silicified coal is easier to oxidize and spontaneous combustion; the volume fraction of the marker gas generated in the oxidation process of silicified coal is always higher than that of non-silicified coal, and when the temperature rises to 110 ℃, the difference in the volume fraction of the gas products of the two coal samples gradually becomes larger, which may be because silicification causes physical and chemical changes in coal body and its molecular structure, leading to oxidation cracking of silicified coal more easily; the rate of oxygen consumption and CO formation of silicified coal is always higher than that of non-silicified coal, indicating that silicification enhances the low temperature oxidation characteristics of coal.

       

    /

    返回文章
    返回