| The fire prevention and extinguishing problem about reasonable nitrogen injected in Spontaneous combustion seam of goaf is researched by using goaf field flow method. G3software, the numerical simulation software of the three zones for spontaneous combustion, is used as a analysis platform to determine the relationship between every factor and spontaneous oxidation zone width by simulating the influence air quantity, nitrogen injection change make on goaf spontaneous oxidation zone under the specific conditions. Theoretically, the spontaneous oxidation zone width will widen with air quantity increased and will narrow with nitrogen injection increased. The result of theory and numerical simulation are the same, the curve of relationship between air quantity of work face, nitrogen injection and oxidation width. The reasonable parameter of nitrogen injected can be determine according to the change of air quantity or the reasonable advance rate of working face can be determine according to oxidation width to keep the residual coal in oxidation are in shortest ignition period.On the basis of the theory, the air quantity and ventilation resistance of working face are measured with examples of the fully mechanized top-coal caving working face825in Jiudaoling Mine, the reasonable nitrogen injection under the existing technology conditions, the change of nitrogen injection and advance rate of working face under the change of air quantity can be determine by the multi-component gas’ Concentration distribution and temperature distribution got with the method of burning beam tubes in goaf.The study provides a useful means for the safe mining in spontaneous combustion coal seam (top-caving mining) and the determination of reasonable working face length during mining design, which is favorable for preventing the coal’s spontaneous combustion in goaf thoroughly and utmostly. |
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