热重分析法研究不同添加剂对煤粉的催化燃烧

Catalytic combustion of different additives on coal studied by thermogravimetry

  • 摘要: 采用热重分析法和统计分析方法研究了原煤及加入不同添加剂后煤粉的燃烧效果.加入质量分数为2%的MnO2、CaO和CeO2可将原煤的活化能由98.07分别降至73.73、78.50和76.45 kJ·mol-1,原煤的燃烧放热峰温度也随之降低,由534.2分别降至482.7、489.4和484.9℃,但对氧化放热峰温度影响不明显,两者作用结果可将原煤氧化峰与燃烧峰对应温度差减小约30℃.添加剂对煤粉燃烧活化能和燃烧峰温度的影响规律符合玻尔兹曼方程拟合的函数关系,燃烧放热峰对应温度降低,活化能也减小,可通过煤样差热分析曲线中燃烧峰对应温度值粗略估计煤样的活化能.

     

    Abstract: The combustion process of raw coal with different additives was characterized by thermogravimetry and statistical analysis. It is found that the activation energy of raw coal can be reduced from 98.07 k J-tool-1 to 73.73, 78.50, and 76.45 kJ·mol-1 by adding MnO2, CaO, and CeO2 with the mass fraction of 2%, respectively. The exothermic peak temperatures of combustion are separately lowered from 534.2 to 482.7, 489.4, and 484.9 ℃, but the additives have little effect on the exothermic peak temperature of oxidation, leading to a 30 ℃ reduction of distance between the oxidation peak and the combustion peak. The effects of additives on the activation energy and the combustion peak accord well with the Boltzmann equation fitted through experimental data. The lower the exothermic peak temperature of combustion, the smaller the activation energy is. Thus the activation energy can be approximately evaluated from the exothermic peak temperature of combustion in the differential thermal analysis curve.

     

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