Experimental Study On The Influence Of Water Immersion Degree On Coal Spontaneous Combustion Characteristics

Spontaneous combustion of coal is one of the main disasters threatening the safety of coal mining.During coal mining,cracks in the coal seam cause groundwater to flow in,changes in spontaneous combustion characteristics of soaked coal.It is of great significance to use experimental methods to study the spontaneous combustion characteristics of coals with different degrees of water immersion.Using the temperature-programmed oxidation experiment,analyze the gas generation law and the comprehensive judgment index of the spontaneous combustion tendency in the spontaneous combustion oxidation process.The results show that,compared with raw coal,the higher the degree of water immersion,the more CO,CO₂ and Cx Hy gases are generated,the faster the generation rate,the earlier time when coal enters the oxidation stage in the process of spontaneous combustion,the lower cross-point temperature,and the smaller judgment index of spontaneous combustion tendency,indicating that the higher degree of water immersion,the easier it is to spontaneous combustion.TG-DSC combined with synchronous thermal analysis experiment is used to analyze the change rule of coal mass and heat release during the heating process.Compared with raw coal,the higher degree of water immersion,the more characteristic temperature points shifted to the low temperature zone,the faster weight loss rate,the more heat release,the higher activation energy of water loss,the lower activation energy of thermal decomposition,and the more intense the oxidation reaction.Using scanning electron microscopy experiments and nitrogen adsorption experiments,analyzing the surface structure characteristics,average pore size of coal samples.The result shows that the degree of water immersion increases,the pores and cracks increases,and the connectivity between the cracks is better,which is conducive to the adsorption of oxygen,and the oxidation spontaneous combustion is increased.Using fourier infrared spectroscopy technology,coal samples of different water immersion levels have higher oxygen functional group content and lower aromatic hydrocarbon group content.Figure 27;Table 24;Reference 56...