硫含量对无烟煤自燃特性影响实验研究

Effect of sulfur content on spontaneous combustion characteristics of anthracite

  • 摘要: 煤自燃过程受多种因素的影响,现有研究主要从煤变质程度、供氧浓度、供风量、空气湿度、粒度和含水率等方面对煤自燃特性进行探讨,然而煤中硫元素的含量也是影响煤自燃的重要因素之一。为探究硫含量对无烟煤自燃特性及氧化动力学参数的影响规律,利用管式炉程序升温实验系统对5种不同硫含量煤样的氧化过程进行了测试,定量分析了不同硫含量对煤低温氧化过程中CO,CO2气体释放特性及自燃特征温度的影响规律。通过计算不同硫含量煤样在不同温度条件下的耗氧速率,定量考察了耗氧速率随温度的变化规律。运用化学反应动力学原理计算出不同硫含量条件下煤样的表观活化能,定量分析了表观活化能随硫含量的变化规律。结果表明:当硫含量不变时,CO和CO2浓度、耗氧速率随温度的升高均呈指数级增长,表观活化能则逐渐减小;随着硫含量的增加,各温度点的CO和CO2浓度、耗氧速率呈现出先增加后减少的变化规律,在硫含量为5.14%处达到最大值;自燃特征温度和表观活化能则呈现出相反的变化规律,在硫含量为5.14%处达到最小值,此时煤样自燃倾向性最大,即硫含量对无烟煤自燃倾向性影响的临界值为5.14%。

     

    Abstract: The spontaneous combustion process of coal is influenced by multiple factors. Existing studies mainly investigate coal spontaneous combustion characteristics from aspects such as coal metamorphic degree, oxygen concentration, air supply rate, air humidity, particle size, and moisture content rate. However, the sulfur content in coal is also one of the important factors affecting coal spontaneous combustion. To investigate the effects of sulfur content on the spontaneous combustion characteristics and oxidation kinetic parameters of anthracite, oxidation processes of five coal samples with different sulfur contents were tested using a programmed temperature-rise experiment system with a tube furnace. The effects of different sulfur contents on CO and CO2 gas release characteristics and characteristic temperatures of spontaneous combustion during the low-temperature oxidation process of coal were quantitatively analyzed. By calculating the oxygen consumption rates of coal samples with different sulfur contents under different temperature conditions, the variation pattern of the oxygen consumption rate with temperature was quantitatively examined. Based on chemical reaction kinetics, the apparent activation energies of coal samples under different sulfur contents were calculated, and the variation pattern of apparent activation energy with sulfur content was quantitatively analyzed. The results showed that when the sulfur content remained constant, the concentrations of CO and CO2 and the oxygen consumption rate increased exponentially with increasing temperature, while the apparent activation energy gradually decreased. With increasing sulfur content, the concentrations of CO and CO2 and the oxygen consumption rate at each temperature point first increased and then decreased, reaching maximum values at a sulfur content of 5.14%. In contrast, the characteristic temperature of spontaneous combustion and the apparent activation energy showed opposite trends and reached minimum values at a sulfur content of 5.14%, at which point the coal sample exhibited the strongest spontaneous combustion tendency. Therefore, the critical sulfur content affecting the spontaneous combustion tendency of anthracite was 5.14%.

     

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