【摘要】 基于静态耗氧实验、热分析实验及红外光谱实验结果,结合煤低温氧化阶段的宏观耗氧放热规律及微观活性基团含量变化,对煤的化学动力自氧化加速温度进行了探讨。基于静态耗氧实验结果所得的活化能变化规律显示,随温度升高,煤氧复合的活化能逐渐减小,较高温度时出现负活化能,标志着煤氧复合反应进入自发反应阶段;利用补偿效应推导了等动力学温度点Tiso的计算公式,得到实验煤样的Tiso为127℃。在Tiso附近,煤中还原性强的基团急剧减少而含氧基团快速增加;另用热重-差示扫描量热TG-DSC实验结果计算得到在Tiso附近活化能达到最低。微观结构变化和宏观放热特征证实了计算所得Tiso与煤自氧化加速点的相关性,认为可将等动力学温度点Tiso视为煤从低温缓慢氧化进入自活化反应阶段的临界点,即自氧化加速温度点。更多还原

【Abstract】 Based on the results of the static oxygen-consumption experiment,thermogravimetry-differential scanning calorimetery(TG-DSC) test and Fourier Transform Infrared Spectroscopy(FTIR) test,the self-accelerating oxidation temperature during coal’s spontaneous combustion was discussed.According to the computation results of the static oxygen-consumption experiment,the activation energy during different coal oxidation stages was calculated.The results show that the activation energy gradually reduces with the rising temperatures,and a negative value appears in the higher temperature stage,which indicates that the coal enters into the self-accelerating spontaneous reaction.The calculation formula of the isokinetic temperature point(Tiso) was deduced combining with the compensation effect,and the Tiso was calculated as 127 ℃ for the experimental coal sample.FTIR experiment results indicate that the microscopic deoxidizing structures reduce greatly and the oxidizing active groups swiftly increase around Tiso.Moreover,according to the TG-DSC results,the lowest activation energy is also close to Tiso.Therefore,from micro structures and macro heat release characteristics,the isokinetic temperature point Tiso can be considered as the critical temperature,which is the self-accelerating oxidation temperature,when the coal enters into the self-activation reaction stage.更多还原