利用热重法研究不同氧浓度对煤自燃特性的影响

煤自燃受到多种因素影响,为了研究煤与氧气反应的机理,通过热重(TG)实验测试了褐煤、1/3焦煤和无烟煤在不同氧气体积分数条件下的自燃特性,分析了煤样氧化过程的特征温度、质量损失、热效应及热反应动力学参数。研究结果表明:不同煤阶的煤样对氧气的化学响应特征不同,煤阶越高,越难以发生氧化反应,体现为特征温度增大,放热峰值减小,并且向高温区域偏移;随着氧气体积分数的增大,煤更易与氧气发生反应,褐煤、1/3焦煤和无烟煤的放热量分别增加到14 131、11 424、12 263 J/g;对煤受热剧烈反应的分解燃烧阶段进行分析,发现煤阶越高,其表观活化能越高,不同氧气体积分数条件下各煤样的表观活化能呈波动变化。

Study on the effects of different oxygen concentrations on spontaneous combustion characteristics of coal with thermogravimetric method

Spontaneous combustion of coal was affected by many factors.In order to study the mechanism of reaction between coal and oxygen,thermogravimetric(TG)experiments were conducted to test the spontaneous combustion characteristics of lignite,1/3 coking coal and anthracite under different oxygen volume fractions.The characteristic temperature,mass loss,thermal effect and kinetic parameters of coal sample oxidation process were analyzed.The results show that the response characteristics of different coal ranks on oxygen volume fraction are inconsistent,the higher the degree of coal,the more difficult it is for oxidation to occur,it shows that the characteristic temperature increases,the peak value of exothermic heat decreases,and shifts to the high temperature region;with the increase of oxygen volume fraction,it is easier for coal to react with oxygen,and the heat release of lignite,1/3 coking coal and anthracite increase to 14131 J/g,11424 J/g and 12263 J/g respectively;the decomposition and combustion stage of coal under intense heat reaction is analyzed,and it is found that the higher the coal rank is,the higher the apparent activation energy is,the apparent activation energy of each coal sample fluctuates under different oxygen volume fraction.