Research On Cooling And Heating Technology Of Circulating Water In Coal Seam Of Advanced Working Face

With the increase of mining depth,the problem of heat damage in working face is becoming more and more serious,which threatens the health and safety of underground workers and reduces the mining efficiency of coal resources.The heat dissipation of high-temperature coal seam is the main cause of heat damage in working face.At the same time,the thermal energy resources stored in the coal seam have a certain utilization value,so it is of great significance to combine the treatment of thermal damage in the mining face with the utilization of thermal energy in the coal seam.Because of its special geological conditions,Ping Mei coal mine has serious underground heat damage problem and high temperature of coal seam.In this paper,the mining face of Ping Mei mining area is taken as the research background,and the methods of field investigation,theoretical analysis,laboratory experiment and numerical simulation are comprehensively adopted to explore and study the cooling and heat mining technology of high-temperature coal seam.The main research results are as follows:（1）Collect and sort out the geological data of Ping Mei mining area,analyze the cause of the abnormal geothermal gradient in mining area;The ventilation parameters and coal seam temperature of the working face are measured,the heat source of the working face is analyzed and the heat dissipation is calculated.It is proved that the heat dissipation of the high temperature coal seam is the main cause of heat damage of the working face and it has the value of heat energy utilization.（2）Based on the single-well circulating water source heat pump technology,the heat transfer mechanism of circulating water in coal seam was studied,the relationship between seepage and temperature field in coal seam was analyzed,and the thermal conductivity of coal was determined to be the main parameter affecting heat transfer.The moisture content of coal samples in working face is measured and the thermal conductivity of coal is measured.The rule that the thermal conductivity of raw coal increases with the increase of moisture content is obtained.（3）According to the working parameters of coal seam and the thermal characteristic parameters of coal seam,using numerical simulation software to build coal seam physical model of circulating water heat exchanger,put forward the control equations and boundary conditions of calculation model,coal seam in circulating water cooling and thermal effect of simulation research.It is concluded that coal seam temperature field with the change of time and the extraction of water temperature variation characteristics,simulation analysis under the condition of different water flow rate and borehole spacing,extraction water temperature and temperature field change of coal seam.（4）According to the geological and production technical conditions of the working face,combined with the results of different numerical simulation schemes and the cooling demand of the working face,the optimal parameters of drilling and water injection are determined.The technology scheme of cooling and heat recovery of circulating water in coal seam in advance working face is formulated.The simulation analysis shows that mining low temperature coal seam can reduce the ambient temperature of working face by 2-3℃.The thermal energy reserve of coal seam is calculated to be 4.92×10¹⁵J by heat storage method,and the coal seam is determined to have abundant geothermal resources.The thermal energy utilization scheme of coal seam in working face is put forward.This paper comprehensively evaluates the economic and social influence of cooling and heat extraction technology in high temperature coal seam.The paper has 47 pictures,15 tables,and 69 references.