Experimental Study On Critical Temperatures And Characteristics Of Spontaneous Combustion Under Low Temperature Of No.2 Coal Of Lingwu Mine

The production and consumption of coal all play the leading role in the world, but coal spontaneous combustion seriously threatens the production safety of coal mines, and leads to working face closing, even ceasing production, it also can cause gas, coal dust and water gas explosion or smoke and flame which envenom coal mines and fatalities. Coal spontaneous combustion can be devided into three periods: latent period, self-heating period and spontaneous ignition period or efflorescence period. Latent period is the low temperature heat accumulating step, self-heating period is accelerating oxidation and temperature increasing step, the temperature changing point is called critical temperature. It's significant to research the critical temperature and characteristics for deeper research on procedures and mechanism of coal spontaneous combustion under low temperature.Taking coal No.2 as experimental sample, first, expatiate on procedures and essence of coal oxidation and spontaneous combustion according to coal spontaneous combustion mechanism analysis, it is because coal oxidation releases heat which accumulates in suitable environment and cause temperature increasing, then comes spontaneous combustion, critical temperature is the sudden changing point in coal spontaneous combustion. Then, XK-IV coal spontaneous combustion experiment system is used to simulate coal No.2 sample'spontaneous combustion procedures, coal temperature relationship is figured out, according to definition of critical temperature and macro performance, relationships bwtween coal spontaneous combustion characteristic parameters and coal temperature are worked out, such as O2 consumption rates, heat releasing intensity, temperature increasing rate, CO and CO2 generating rates etc. Based on that, method for determing coal critical temperature is raised, the critical temperature, characteristic parameters and their changing rates of coal NO.2 under critical temperature are figured out. Finally, original coal sample is breaked up into different grain diameters, water or air temperature programming experiments are carried out in same experimental conditions, according to experiment results, the influence of coal grain diameter on critical temperature and characteristic parameters of coal are analysed.According to the research on key temperature changing point in coal spontaneous combustion-critical temperature and its characters, this research is theoretically significant for deep understanding on coal spontaneous combustion procedures and tokening coal spontaneous combustion tendency quantitatively.