Study On Distribution Law Of Spontaneous Combustion "Three Zones" In Goaf Of 11301 Fully Mechanized Mining Face In Taishan Longan Coal Industry

Coal plays an important supporting role in China’s energy consumption and plays an important role in China’s energy security.According to statistics,about 50%of key coal mines in China have the risk of coal spontaneous ignition,which seriously threatens the safe and efficient mining of coal resources.Due to air leakage and other reasons,it is easy to cause spontaneous ignition of coal in mined-out area of stoping face,which leads to coal mine fire.The study of the law and distribution characteristics of spontaneous combustion in goaf is the key to take effective fire prevention measures.This thesis studies the spontaneous combustion of coal in 11301working face of Taishan Longan mine,master the characteristic parameters of spontaneous combustion of coal,do a good job in forecasting and forecasting of spontaneous combustion of coal,and determine the distribution the distribution of self-ignition“three zones”distribution,which has important guiding significance for the formulation of comprehensive fire prevention and control technical measures.The research results are as follows:（1）Through the heat oxidation experiment measured the coal sample and the generation rate of CO,CO₂ and hydrocarbon gases,through the analysis of the volume fraction of each component gases,format fire coefficient ratio,alkane ratio and olefin-alkyl ratio with the change of the temperature,the division of the different stages of the coal sample oxidation,into the various stages of the critical temperature of coal is determined,and combining the principle of coal spontaneous combustion prediction mark gas optimization,The indicator gas and auxiliary gas parameter indexes are selected to predict coal spontaneous combustion,and a multi-index gas parameter early-warning index system is established.（2）By analyzing the variation rules of gas components and volume fraction in the goaf of 750m,650m,600m and 550m respectively,it can be found that there is no abnormal temperature in the existing goaf,and no alene and alkyne gases are detected in the measurement of goaf gas.Therefore,it is considered that there is no coal spontaneous combustion in the goaf of this working face.The volume fraction of O₂shows a general trend of decline,while the concentration of CO gas shows a trend of increase,and the change of CO concentration increases sharply from November 3,indicating that the recombination effect of coal oxidation is accelerated and olefin gas is about to be generated.At this time,corresponding fire prevention measures should be taken as soon as possible.（3）The gas in goaf of 11301 working face of Longan Coal Mine in Taishan was collected and tested underground,and the variation law of gas composition and gas concentration in goaf with temperature was analyzed,and the distribution range of spontaneous combustion in goaf of fully mechanized working face was determined:At the inlet side,0～27.2m is the heat dissipation zone,27.2～82m is the oxidization combustion zone,and greater than 82m is the asphyxiation zone.On the return air side,0～17.6m is the heat dissipation zone,17.6～67m is the oxidization combustion zone,and greater than 67m is the asphyxiation zone.（4）According to the measured“three zones”range of spontaneous combustion in goaf and the shortest natural combustion period of coal seam,the minimum propulsion degree of working face is calculated to be 2.05m/d,that is,the daily propulsion degree is not less than 2.05m to ensure the goaf in a safe state.（5）Put forward the comprehensive fire prevention technology measures combining nitrogen injection fire prevention technology,chemical inhibitor fire prevention technology and pressure equalization fire prevention measures for the mine.The technique of nitrogen injection for fire prevention and control adopts open nitrogen injection and continuous nitrogen injection.Working face inhibitor concentration is 15%,the amount of inhibitor required for a spray is 40.6kg;Two nitrogen injection machines were used to inject nitrogen into the goaf at the same time,and the goaf buried double-pipe stepping method was adopted,with a step distance of30m.There are 35 figures,22 tables,50 references in this thesis.