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不同浸水率煤矸石浸水复干氧化特性研究

Study on oxidation characteristics of coal gangue with different moisture content under water immersion drying

  • 摘要: 露天堆积的煤矸石受雨水浸泡发生变化,在不同降水量区域表现出具有差异性的自燃倾向。为了研究水分对煤矸石氧化自燃的作用和影响,采用内蒙古棋盘井地区易自燃中高硫煤矸石进行研究。首先,对煤矸石进行不同浸水率(0、15%、30%、50%、100%)的浸泡试验,浸泡45 d后对煤矸石进行自然风干;将干燥后的矸石样品放入自制程序升温试验炉进行升温试验(升温速率设置为3 ℃/min,升温范围设置为30~390 ℃),使用集气袋收集煤矸石在各阶段温度点的气体(以每升高15 ℃为1个阶段),最后将采集气体通入GC-4000A型气相色谱仪。通过对比煤矸石在不同浸水率处理后的O2消耗及CO、CH4、C2H4、C2H6等指标气体生成的体积分数变化,结果表明:煤矸石在浸水率为15%时的低温氧化特性最佳,CO、CH4、C2H4、C2H6等指标气体初始生成温度最低,当温度在390 ℃时产生各类指标气体体积分数最大;当浸水率超过50%时,在水分的溶解作用下,煤矸石中大量可燃物质被水分携带逸散,导致该浸水率煤矸石升温至390 ℃时生成的各类指标气体体积分数显著降低,甚至低于未经过浸水复干处理的对照试验组;煤矸石在水分的浸泡作用下,生成各类指标气体的初始温度点均降低约15 ℃。

     

    Abstract: Coal gangue, which accumulates in the open air, is modified by immersion in rain, and exhibits different tendencies to spontaneous combustion in different areas of precipitation. To study the role and influence of moisture on the oxidation and spontaneous combustion of coal gangue, we used high-sulfur coal gangue prone to spontaneous combustion in the Qipanjing area of Inner Mongolia. First, the coal gangue is soaked with different moisture content (moisture content: 0, 15%, 30%, 50%, 100%). After soaking for 45 days, the coal gangue is naturally air dried. The dried gangue samples were put into the self-made programmed temperature experiment furnace to conduct experiments on the pre-treated coal gangue samples (the temperature rise rate was set at 3℃/min, and the temperature rise range was set at 30−390 ℃). The gas the temperature points of the coal gangue in each stage was collected by air collecting bag (each rise of 15 ℃ was a stage). Finally, the collected gas was passed into the GC-4000A gas chromatograph. By comparing the O2 consumption、the volume fraction of CO, CH4, C2H4, C2H6 and other index gases produced by coal gangue treated with different moisture content, the results show that: The low temperature oxidation of coal gangue is the best when the moisture content is 15%, the initial formation temperature of CO, CH4, C2H4, C2H6 and other indicator gases is the lowest, and the concentration of various indicator gases is the highest when the temperature is 390℃. When the moisture content exceeds 50%, under the action of moisture dissolution, a large number of combustible substances in the coal gangue are carried and dispersed by moisture, resulting in a significant decrease in the concentration of various indicator gases generated when the moisture content of the coal gangue rises to 390 ℃, even lower than that of the control experimental group without moisture immersion and redrying treatment. When the coal gangue is immersed in water, the initial temperature points of the various index gases are reduced by about 15 ℃.

     

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