| Coal dust explosion has always been a hot,important and difficult issue in the field of mine safety production.Coal is a porous medium with a complex structure.It not only contains a solid framework of macromolecules,but also contains some small molecular soluble organic matter,which occurs on the surface and pores of the coal.The soluble organic matter can dissolve part of the methane gas.Dust explosion will have a certain impact.This thesis adopts the methods of theoretical analysis and experimental research to study the influence mechanism and law of coal soluble organic matter on coal dust explosion.Based on the theories of combustion and explosion,gas flow and diffusion,and using the method of theoretical analysis,the influencing factors of coal dust explosion are studied,and the pore structure characteristics of coal and the composition of soluble organic matter are analyzed and studied by scanning electron microscopy and infrared spectroscopy experiments.The influence mechanism of soluble organic matter on coal dust explosion.The organic solvent ethyl acetate was used to extract the coal sample.The specific surface area and pore size analyzer was used to test the pore volume and pore distribution characteristics of the coal sample before and after extraction.The particle size distribution of the coal sample before and after extraction was tested by the laser particle size analyzer.Obtain the average diameter D50,Sauter average diameter D3,2and the degree of dispersion.Studies have shown that after the organic matter in coal is extracted,the average pore diameter and pore volume of coal increase,the maximum increase is 46.6%and 9.92%,the total specific surface area decreases,and the maximum decrease is 45.8%.The average diameter and the average diameter of Sauter decrease,and the average diameter of Sauter decreases.The diameter is reduced by up to 63.6%,and when the extraction time is 18h,the dispersion is reduced.The coal samples before and after extraction with ethyl acetate are made into standard coal samples ofΦ50mm×100mm,and uniaxial compression and Brazilian splitting experiments are carried out on the samples using YA-600 electro-hydraulic servo universal testing machine.According to rock mechanics and elasticity Damage mechanics and other theories,analyze and study the changes in compressive and tensile strength of coal samples before and after extraction.Studies have shown that the compressive and tensile strength of the sample after extraction are significantly improved,in which the compressive strength is increased by up to 1.37 MPa,and the tensile strength is increased by up to 45.7 k Pa.The coal samples before and after extraction were used to conduct explosion experiments with a 20L spherical explosion instrument.According to the theory of combustion and explosion,the explosion pressure and lower explosion limit of coal samples before and after extraction were compared and analyzed,and the influence of soluble organic matter in coal on the explosion characteristics of coal dust was studied..Studies have shown that the lower explosion limit of coal samples after extraction has been increased,with a maximum increase of 17.3%,and all explosion pressures have been reduced,with a maximum reduction of 7.8%.Among them,the coal dust explosion index of the maximum explosion pressure has dropped significantly,with a maximum reduction of 1.52MPa·m/s.The paper reveals the mechanism and law of the influence of organic matter in coal on coal dust explosion characteristics.The removal of soluble organic matter can increase the lower limit of coal dust explosion and reduce the pressure of coal dust explosion,which has certain safety significance.From the perspective of soluble organic matter control in coal,Can provide a new way and method for the prevention and control of coal dust explosion. |
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