Study On The Production Mechanism And Safety Index Of CO In The Process Of Coal Oxidation

Most of the coal seams belong to easily spontaneous combustion and spontaneouscombustion coal seams in our country.The course of normal mining in high-yield andhigh-efficiency mines, CO is often accumulated in the return corner of face,because ofhigh-mining intensity,easily oxidation of coal seams and so on. Coal spontaneous combustionprediction is disturbed and mine production safety is affected. Production mechanism of CO,and rule of accumulation and control are always key scientific problems of mine spontaneouscombustion hazard prevention. The main coal seam of Lingwu mining area is chosen as theresearch subject in the paper, micro dynamics of CO production, accumulation rule, safetyindex, prevention and control method are studied. It provides the basis for the early predictionof the coal spontaneous combustion and CO overrun management in goaf.Taking main coal seam samples of Lingwu mining area, through the ultimate analysisand infrared spectrum, coal molecular structure containing the main active group type isobtained.Basis on the quantum chemical density functional, Gaussian-03W software wasemployed to simulate the dynamic process of CO desorption of the main active group of coal,and three steps of CO producing in the process of coal oxidation are obtained according to thesimulation theoretical analysis.Using the coal spontanepous combustion temperature programmed experimentequipment, the CO generation rule under different oxygen concentration are discovered bytesting the coal sample at oxygen concentration of4%,8%,12%,14%,18%and21%. Thequantificationally functional relationship between the temperature at low level and COgeneration were established. The three processes of the CO generation were found. Thegeneration of CO was influenced by both of temperature and O2concentration in each process.The property parameters and limit parameters in the process of coal spontanepous combustionare got by the coal spontanepous combustion experiment equipment. It provides the basis foranalyzing the accumulation rule in goaf. By means of detecting and theoretical analysis of CO and O2of5typical faces, theinteraction rule among CO, O2and depth in goaf was obtained. The relations among CO atreturn corner, air distribution, advancing speed and recovery rate were analyzed by the greyrelation analysis theory. The governing equation of CO generation and accumulation in goafwere established. The accumulation rule under normal production conditions are found outvia the simulation by FLUENT software.Calculation model of safety critical index of CO concentration in return corner wasfounded. According to the practice mining condition, three typical working faces are studiedincluding high cutting height face, full-mechanized caving face, full-mechanized face inLingwu mining area, and the safety index of CO concentration in return corner of workingface. Index of spontaneous combustion forecast is offered, and it’s beneficial to safetyproduction of the mining face.Based on the rule of the generation and accumulation of CO, and the mining conditionin main mining coal seam of Lingwu coal area, the method of CO controlling is put forward,which is adopted in Lingwu coal area, and is applied successfully to control CO in goaf underthe condition of sealed during stoppage and support withdraw, and ensure the mining facere-opening safety.