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长焰煤粉爆炸特性及微观机理研究

Explosion characteristics and microscopic mechanism of long-flame pulverized coal

  • 摘要: 在煤炭的生产、运输、加工及使用过程中容易产生粉尘云,遇到点火源易发生爆炸事故。以海则庙煤矿长焰煤为研究对象,采用TG-DSC测试和20 L爆炸球实验,研究了煤粉的氧化及爆炸特性参数;利用FTIR测试了爆炸前后煤粉官能团的变化;结合Chemkin-pro模拟了煤粉爆炸反应路径、不同当量比下压力敏感性及自由基产率变化,揭示了煤粉爆炸反应机理。结果表明:煤粉氧化300℃时加速失重,总损失为93.1%。煤粉浓度为500 g/m3时最大爆炸压力达到0.57 MPa,最大爆炸压力上升速率为318.38 MPa/s。煤粉爆炸过程中,含氧官能团和脂肪烃化学键断裂,释放可燃气体和生成自由基片段。爆炸过程中,3种自由基耦合反应:·HO2+·H=·OH。自由基产率影响着Pmax和(dp/dt)max。煤粉产生可燃气体与自由基发生链式反应,产生能量加速爆炸反应进程。研究结果对煤粉爆炸事故分析提供了参考依据。

     

    Abstract: In the process of coal production, transportation, processing and use, it is easy to produce dust clouds, and it is easy to have explosion accidents when encountering ignition sources. Taking long flame coal in Haizemiao Coal Mine as the research object, the oxidation and explosion characteristic parameters of pulverized coal were studied by TG-DSC test and 20 L explosive spheres. The changes of functional groups of pulverized coal before and after explosion were measured by FTIR. Combined with Chemkin-pro, the reaction path of pulverized coal explosion, the sensitivity of pressure under different equivalent ratio and the change of free radical yield were simulated, and the mechanism of pulverized coal explosion reaction was revealed. The results show that the weight loss is accelerated at 300℃ and the total loss is 93.1%. When the concentration of pulverized coal is 500 g/m3, the maximum explosion pressure reaches 0.57 MPa and the rise rate of the maximum explosion pressure is 318.38 MPa /s. In the process of pulverized coal explosion, the chemical bond between the oxygen-containing functional group and the aliphatic hydrocarbon is broken, the flammable gas is released and the free radical fragment is formed. In the explosion process, three kinds of free radical coupling reactions: ·HO2+·H=·OH. The free radical yield affects Pmax and (dp/dt)max. Pulverized coal produces combustible gas and produces chain reaction with free radicals, generating energy to accelerate the process of explosive reaction. The research results provide a reference for the analysis of pulverized coal explosion accidents.

     

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