基于活化能计算的煤低温氧化特征与临界点预测

为探究煤自燃过程的反应特征与预测煤自燃临界温度,对5种煤样进行了绝热氧化实验,采用煤样活化能指标在实验不同时间段的变化情况来表征煤低温氧化内在特征。然后运用线性回归性分析模型中线性显著性检验来确定临界温度点Tc。结果表明:实验初期煤样活化能波动范围极大,随着温度升高活化能趋于稳定,在实验后期,各煤样求得的活化能均处于55~70kJ/mol范围内,反映了煤低温氧化反应是由不稳定逐步过渡到相对稳定的过程;Tc与宏观升温速率突变范围相符合,验证了模型的准确性;同时Tc与实验中自热温度达到160℃所需时间t0自发呈线性关系,因此可以用绝热氧化装置测得t0来预测煤自燃临界点。研究成果可以对矿区防灭火和煤炭储运管理工作提供借鉴。

Characteristics of low temperature coal oxidation and prediction model of critical point based on activation energy calculation

To investigate the characteristics of adiabatic oxidation reaction and predict critical temperature of coal spontaneous combustion,we carry out the adiabatic oxidation experiments of five coal samples and use the index of activation energy to reflect the characteristics of microcosmic reaction of spontaneous combustion in different stages.In addition,the critical point (Tc) is determined by using the F test of linear regression analysis.The results show that in the early stage of low temperature oxidation of coal,the values of activation energy range greatly,which indicates that reactions of the functional groups is very unstable at this time;as the temperature increases,the values of all samples are in a range of 55 to 70 kJ/mol in late period of the experiment,which indicates that the reaction has become relatively stable;Tc has good correlation with macro-heating rate,which indicates the model is scientific.In addition,Tc has linear relationship with t0 (the time needed for spontaneous combustion temperature increasing to 160 ℃ in the experiment).Thus Tc could be predicted by t0.This research could provide reference for the prevention fire and coal storage in mine.