断层构造对煤结构及氧化自燃特性的影响

Effect of fault structure on the structure and oxidative spontaneous combustion characteristics of coal

  • 摘要: 为探究断层构造对煤结构及自燃特性的影响规律,以红庆梁煤矿11301工作面断层构造煤和原生煤为对象,采用红外光谱FT-IR实验、热重分析实验、低温氮气吸附实验和封闭式煤氧化实验,分别从微观和宏观角度对煤样的活性基团含量、燃烧特征温度、孔隙结构特征、耗氧速度和氧化放热强度进行分析。红外光谱FT-IR实验结果表明,断层构造煤的活性基团多于本煤层原生煤,断层构造煤的氧化活性高;热重分析实验表明,断层构造煤的裂解温度、临界温度、着火温度、峰值温度和燃尽温度均低于原生煤,断层构造煤表现出更强的自燃倾向性;低温氮气吸附实验结果表明,断层构造改变了煤的孔隙结构,相较于原生煤,断层构造煤比表面积增幅为2.5倍、平均孔径增幅为2.36倍、微孔孔容增幅为2.71倍、介孔孔容增幅为1.69倍。断层构造作用对煤体的孔隙结构特征的影响,便于氧气进入煤体与孔隙中的活性基团发生氧化反应;通过封闭式煤氧化实验可知,温度25~70℃条件,煤的耗氧速度、CO释放速度、CO2释放速度和氧化放热强度随温度升高呈指数增长;在氧体积分数为20%、温度25~70℃条件,红庆梁煤矿11301工作面断层构造煤的氧化放热强度是原生煤的1.37~2.00倍。断层构造煤相对于本煤层原生煤自燃倾向性更强。本次研究从微观和宏观角度揭示了实际采掘环境中断层构造煤更易发生自燃的原因是改变煤自身结构和自燃环境因素,使之更有利于自燃。

     

    Abstract: In order to investigate the influence law of fault tectonic on coal structure and spontaneous combustion characteristics, the fault tectonic coal and primary coal in No. 11301 working face of Hongqingliang coal mine were taken as study samples. The FT-IR experiment of infrared spectrum, thermogravimetric analysis experiment, low temperature nitrogen adsorption experiment and closed coal oxidation experiment were used to analyze the active group content, combustion characteristic temperature, pore structure characteristics, oxygen consumption rate, and oxidation heat release intensity of coal samples from a micro perspective and a macro perspective separately. The results of the FT-IR experiment of infrared spectrum showed that the active groups of the fault tectonic coal were more than those of the native coal, and the oxidation activity of the fault tectonic coal was high. The results of the thermogravimetric analysis experiment showed that the cracking temperature, critical temperature, ignition temperature, peak temperature and combustion temperature of the fault tectonic coal were lower than those of the native coal, and the fault tectonic coal showed a stronger tendency of spontaneous combustion. The results of the low temperature nitrogen adsorption experiment showed that the fault tectonism changed the pore structure of the coal, and compared with the native coal, the specific surface area of the fault tectonic coal increased by 2.5 times, and the average increase of pore size was 2.36 times, the increase of micropore volume and mesopore volume were 2.71 times and 1.69 times respectively. The influence of fault tectonism on the pore structure characteristics of coal was facilitated the oxidation reaction between oxygen and active groups in the pores. The results of the closed coal oxidation experiment showed that under the condition of temperature of 25-70 ℃,oxygen consumption rate, CO release rate, CO2 release rate and oxidative exothermic intensity of coal increased exponentially with the increasing temperature. Under the condition of oxygen concentration of 20% and temperature of 25-70 ℃,the oxidation exothermic intensity of the fault tectonic coal in No.11301 working face of Hongqingliang coal mine was 1.37-2.00 times of the native coal. The tendency of spontaneous combustion was stronger for the fault tectonic coal compared with the native coal of the seam. The whole studies revealed from micro and macro perspectives that the reason why the fault tectonic coal was more prone to spontaneous combustion in the actual mining environment was that the coal's own structure and spontaneous combustion environment factors were changed to make it more favorable for spontaneous combustion.

     

/

返回文章
返回