采用热重法研究煤焦在变温和等温条件下的燃烧过程,分析升温速率和温度对煤焦燃烧行为的影响,用随机孔模型(RPM)研究煤焦的燃烧失重过程,得到了煤焦燃烧变温和等温动力学方程.实验结果表明,变温实验中,随着升温速率的增加,煤焦燃烧的失重曲线向高温方向移动,最大燃烧速率增加,升温速率由5℃/min增加到20℃/min时,最大燃烧速率由3.2%/min增加到11.3%/min;等温实验中,随着燃烧温度的提高,煤焦最大燃烧速率增加,燃烧温度由510℃增加到630℃时,最大燃烧速率由2.1%/min增加到8.3%/min,煤焦燃烧性能得到改善.动力学计算结果表明,RPM能较好描述煤焦变温和等温燃烧过程中煤焦转化率与温度和时间的关系,煤焦变温和等温燃烧的表观活化能分别为84.27和64.16kJ/mol.
The non-isothermal and isothermal combustion processes of coal char were studied by thermogravimetry, and the effects of heating rate and reaction temperature on combustion behaviors analyzed. The weight loss curve of combustion process was fitted by random pore model (RPM), and kinetic parameters obtained. In non-isothermal process, with the increase of heating rate, the weight loss curve moved to high temperature zone, and the maximum weight loss rate increased. When heating rate increased from 5℃/min to 20℃ /min, the maximum weight loss rate increased from 3.2%/min to 11.3%/min. In isothermal process, with the increase of combustion temperature, the maximum weight rate increased, its combustion characteristics were improved. When the combustion temperature increased form 510℃ to 630℃, the maximum weight loss rate increased from 2.1%/min to 8.3%/min. RPM could describe the combustion process of coal char with high accuracy, and the activation energy of non-isothermal process and isothermal process was calculated as 84.27 and 64.16 kJ/mol, respectively.