Simulation Study On Thermodynamic Characteristics Of Spontaneous Combustion Of High-sulfur Gangue Mountain

As the demand and extraction of high-sulfur coal resources increase,the amount of coal gangue produced during the mining and production of high-sulfur coal also increases.Environmental pollution problem caused by the accumulation and spontaneous combustion of high-sulfur coal gangue mountains is getting worse.It is of great significance to carry out research on spontaneous combustion theory and prevention technology of high-sulfur coal gangue to reduce the risk of spontaneous combustion of high-sulfur coal gangue and protect the ecological environment.The nature of spontaneous combustion of high-sulfur coal gangue is spontaneous combustion of high-sulfur coal.Firstly,various sulfur oxidation characteristics of high-sulfur coal on spontaneous combustion of high-sulfur coal and high-sulfur coal gangue was analyzed to study the spontaneous combustion mechanism and influencing factors and of high-sulfur coal and high-sulfur coal gangue.Secondly,an oxidation kinetic model for the spontaneous combustion process of high-sulfur coal was constructed to study the slow oxidation reaction process between high-sulfur coal powder and oxygen,and the thermodynamics and product characteristics of spontaneous combustion of high-sulfur coal in different condition were analyzed.Thirdly,the heat transfer model for the spontaneous combustion of coal gangue was constructed to study the development process of the spontaneous combustion of coal gangue mountain,and influence of environmental conditions on the temperature field characteristics of coal gangue hills mountain was analyzed.The results showed that:1)The high risk of spontaneous combustion of high-sulfur coal gangue is due to the pyrite,the risk of coal spontaneous combustion increases as the sulfur content in high-sulfur coal increases.As the sulfur content increases,the temperature in the coal-oxygen reactor rises significantly,and heat accumulation in local areas is obvious,but influence gradually decreases as the sulfur content increases.The risk of coal spontaneous combustion is greatly affected by the coal and oxygen concentration.Before accumulating high-sulfur coal gangue,the high-sulfur coal in the gangue should be recycled as much as possible and plugging technology should be used to isolate the coal gangue from the air.2)CO₂ has a higher influence on the reaction of high-sulfur coal oxygen compared with N₂,and the cooling effect is better,which can reduce the risk of coal spontaneous combustion.The activity of pyrite only appears in a humid environment.As the humidity increases,the risk of coal spontaneous combustion gradually increases,but the influence gradually decreases.Therefore,the water-injection extinguishing technology should be carefully selected to prevent the secondary fire of coal gangue,and the plugging technology should be adopted to control the environmental humidity.3)The temperature of the coal gangue mountain gradually increases as time increases.When reaches the ignition temperature,it may cause spontaneous combustion of the entire coal gangue mountain.The coal gangue and loess stratified stacking can effectively reduce the risk of spontaneous combustion of coal gangue,and it decreases with the increase of the layer thickness of loess.Coal gangue and loess stratified stacking in the process of stacking coal gangue mountains should be used to reduce the risk of spontaneous combustion of coal gangue.4)Porosity can affect the gas seepage and diffusion flow in coal gangue pores and convective heat transfer between high temperature areas and other areas.As the porosity increases,the risk of spontaneous combustion of coal gangue gradually increases.In the prevention and control of coal gangue spontaneous combustion,compaction of coal gangue can be used to reduce the porosity to control the heat transfer.The risk of spontaneous combustion of coal gangue increases with the stacking height.Therefore,the risk of coal spontaneous combustion can be reduced by appropriately reducing the height of the coal gangue mountain.