Experimental Study On Coal Spontaneous Combustion Characteristics Under Varying Ambient Oxygen Concentration

Study generating regularity of coal spontaneous combustion of coal oxidation products ismostly under the condition of O2concentration was21%at home and abroad,and the study ongenerating regularity of coal spontaneous combustion of coal oxidation products under thecondition of different concentration of O2is less.In the coal mine goaf spontaneouscombustion zone, fire sealing and spontaneous combustion dangerous area,the concentrationof O2in the atmosphere is usually lower than the normal21%,but the occurrence ofspontaneous fire is often happend in the region.By separately at21%,17%,13%,9%,5%,3%oxygen concentration environmenttemperature programmed experiments,analysis of coal sample of Qingshuiying coal mine in20℃~220℃temperature range combustion product concentration changes,determine theCO gas for the detection of spontaneous combustion of symbol, and with CH4, C2H4, C2H6,and CO/CO2as early warning indicators.And found that the critical temperature of the coalsamples under different oxygen concentration points mainly concentrated in60~80℃,theoxygen concentration have no obvious influence to critical temperature point of the same coalsample,although the oxygen concentration to some extent changed the coal-oxygen complexreaction rate, but does not change the rate significantly increased the starting temperature.Through the analysis of specific temperature oxygen consumption rate of coal sample underdifferent under different oxygen concentration environment,it is concluded that oxygenconsumption rate increases with increasing temperature under the same oxygen volumefraction, oxygen consumption rate is low and slow growth in early, late oxygen consumptionrate is high and growing faster;The oxygen concentration in different size may also affectoxygen consumption rate,under the same temperature oxygen concentration, oxygenconcentration greater the higher the rate of oxygen consumption,but with the change in the trend rate of oxygen consumption does not vary with temperature oxygen concentrationchanges.Through the characteristic temperature of the coal spontaneous combustion degree andthe influence to the products of the coal spontaneous combustion oxidation under differentconditions of O2,analysis and calculate the coal oxygen consumption rate,gas productionrate,the intensity of heat and other spontaneous combustion characteristic parameters, moreaccurately control the experimental combustion characteristics of coal samples;At the sametime,analyzed the influence law of temperature of combustion products and their ratio underdifferent oxygen concentrations, provide the basis for making effective control measures tospontaneous combustion,and have a great significance for coal spontaneous combustionforecast.