Study On The Law Of Spontaneous Combustion And Prevention Measures For Trapezoid Coal Stockpile Under Variable Conditions Of Stacking

Spontaneous combustion of coal stockpile has great harm to environment,economy and safety,its influence factors are more and the influence law is complex and changeable,Therefore it is necessary to carry on the research to it in depth.As the applicability and effectiveness of some common coal stockpile spontaneous combustion control technology and the current overall depression situation in the coal industry,There is a pressing need to put forward an economical and reliable method for the prevention and control of spontaneous combustion.Secondary combustion caused by reduction or failure of the original control technique is analyzed and discussed,Owing to unsalable serious coal which causing by prolong the storage period and increase the storage capacity of raw coal stockpile.To ensure the safety of coal stockpile,a fast,convenient,economical and feasible method and strategy of coal stack is designed optimal for fixed point,quantitative and precise intubation.The process of spontaneous combustion of coal pile is influenced by the stacking operational parameters,particle diameter and wind velocity.The former two have a significant impact on the wind range of coal stockpile spontaneous combustion.The influence law and degree on the maximum,minimum spontaneous combustion wind velocity and the initial spontaneous combustion zone for the coal stack are different.The regression quantitative expression of the wind speed range is obtained for coal,spontaneous combustion.The greater the height,the width of the top,the porosity of coal pile and the wind speed.the larger the vertical distance between the initial combustion zone and the top of the coal stack and the upwind slope,the more close to the lower leeward slope and coal heap.A quantitative expression is given for the variation of the initial spontaneous combustion zone with the stacking condition parameters.There are some inapplicable scope for the compaction of coal pile.The inapplicable wind speed range is different from the original porosity,compaction of the target porosity and wind speed,and is not related to the other stacking parameters.The inappropriate compaction equation is given at the different original porosity conditions when the target porosity is 0.2.Combined method of compaction and wind barrier can be prevent the occurrence spontaneous combustion for coal pile effectively in a certain period of effective protection.Combined with the application of Zhongxing coal mine site,for a 6m high coal pile through the use of compaction and wind barrier with 9m high in the distance from the coal pile 20m which guarantee the coal pile compaction to porosity 0.2 in 92 d not occuring spontaneous combustion.The surface water spraying on the coal pile promote the combustion when the temperature is higher than 76℃ in the coal pile,which cause the coal pile to burn quickly and enlarge the combustion area.In this paper,the method of using coal water to prevent fire is put forward,when the method time of compaction and wind barrier exceeds a predetermined amount of time stacking and stacking.The greater the porosity and the particle size,the faster water transport and diffusion.Whether the water outlet angle of intubation is too large or too small will lead to uneven moisture migration and diffusion causing secondary hazard.For a 6m high coal pile,the injection pipe is insert with the ground into a 30 degree angle,pitch 5m,aperture 25mm in the leeward slope from the ground 4-5m,when the single flow is controlled at about 9 t/h,water injection for 30min,it can guarantee the high temperature region disappear.While water injection for 2 h,coal stack achieve almost all of the fire water content,and the safety of coal pile is ensure.