炼焦煤尾煤热解特性及富氢气体析出研究

Characteristics and kinetics of the pyrolysis of coking coal tailings

  • 摘要: 基于热重分析和固定床热解试验,研究了升温速率和温度对高灰炼焦煤尾煤热解规律及产物的影响。采用Coats-Redfern积分法拟合计算了尾煤热解的动力学参数,得出尾煤热解反应活化能为22.6~66.2 kJ/mol,热解反应过程用三个二级反应进行描述。结果表明,温度对尾煤挥发分析出有重要的影响,600 ℃前气体缓慢析出,之后随温度升高,气体产量和热值增加显著,氢气、甲烷和二氧化碳先增加后减,一氧化碳随温度升高而增加;氢气在600 ℃前析出缓慢,之后大量析出,约900 ℃时达到最大析出量(72.61%),之后下降;甲烷(22.09%)和二氧化碳在约800 ℃时达到最大值。30 g尾煤热解气体产量为4.3 L,氢气产量为1.72 L,产物具有较高的再利用价值。

     

    Abstract: The influences of final temperature and heating rate on the pyrolysis characteristics of coking coal tailings and the pyrolysis products were examined by fixed-bed pyrolysis and TG analysis. The tailing pyrolysis kinetics parameters were calculated by using Coats-Redfern method. The activation energy of the pyrolysis of tailings was between 22.6-66.2 kJ/mol, and the process of pyrolysis could be described by three second-order reactions. The results of fixed reactor experiment showed that the temperature had important influence on the tailings volatiles release. There was no gas formation below 600 ℃, and the reaction remarkably occurred after 600 ℃, where the yields and the caloric value of gases increased simultaneously. With the increase of temperature, hydrogen, methane and carbon dioxide first increased and then decreased but carbon monoxide increased. The maximum release of hydrogen (72.61%) and methane(22.09%) appeared respectively at about 900 ℃ and 800 ℃. The tailings pyrolysis by 30 g tailings of coking coal could produce 4.3 L gas and 1.72 L hydrogen. The products had good yields and reuse value. The research is of great significance to guide the tailings disposal.

     

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