Study of the Effect of Coal Dust Particle Size on the Explosion Characteristics and Gas Solid Residue
To reveal the differences of the explosion characteristics of coal dust with different particle size in gas and solid residue, explosion experiments were performed in a 20L spherical explosive device.The explosion characteristics of different particle size of coal dust were recorded, and gas and solid residues were collected and analyzed after the explosion at the same time.The research efforts include the exploration of change laws of composition and volume fraction analysis of gas residue, microscopic morphology analysis and chemical structure analysis of solid residues.The results show that: 1) The maximum explosion pressure of large size coal dust (250-840μrm) was significantly lower than that of the small size of coal dust.Compared with large particle diameter of coal dust (420-840μtm), the maximum explosion pressure of small size coal dust (38-74 μm) increased by 63%, the maximum explosion pressure rising rate increased by 6 times, combustion duration increases by 339%.2) In the confined space, large coal particles >420 μm did not explode at dust concentrations up to 400 g/m3.However, under the same ignition energy, small coal particles <250 μm create explosion at lower dust concentrations (100g/m3).Meanwhile, we found that the gas residues of large size dust which did not explode, existed CO, nitrogen oxide compounds, CH4, C2H6, C2H4 and other hydrocarbon gases.Although 420-840 μm dust did not explode, the pyrolysis reaction still occurred in some coal dust and minor gas was still generated.3) As to the explosive residual gases, with the dust particle size decreases, φ(CH4), φ(O2) and φ(N2) was first increased and then decreased.By contrast, φ(CO2), φ(CO2) was first decreased and then increased.The difference of hydrocarbon gas production is large, φ(CH4) is the highest in the hydrocarbon gas, which is about 6~8 times of φ(C2H6) and φ(C3H8);4)The volatile content of the solid explosive residue decreased by more than 50%, and ash of the solid explosive residue increased by more than 2 times compared with original samples.Through the statistic analysis of the experimental data of solid residue FTIR characteristics, the authors have found that the 539cm-1 vibration peak intensity improved significantly, which indicated that the reactants turn into ash content to a certain extent.The FTIR differences of coal dust samples before and after the explosion was obviously.The hydroxyl at 3619cm-1, aliphatic C-H bonds at 2917 cm-1, 2848 cm-1 and carbonyl at 1905 cm-1 basically disappear.Compared with the large size coal dust, the solid residues of small size coal dust are closer spherical, and chemical structure absorption peak intensity of 900~1800cm-1 wave band of small size coal dust after the explosion decreased more obviously.5) A variety of particle size range of residual particles formed after the explosion test for large particles coal dust (250-850μm).Comparing pre-explosion coal dust, the mass percentage of post-explosion dust that the particle size becomes larger is 2.23%.Overall, the 50.89% percentage of post-explosion dust that particle size becomes smaller increase.This result show that the residues particle size variation regularity has a certain similarity in both combustion and explosion conditions.
coal dust explosion gas and solid residues SEM FTIR particle size distribution
HONG Sen LIU Zhentang LIN Song HANG Sonshan
Department of Key Laboratory of Coal Methane and Fire Control, Ministry of Education, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China;Department of Safety Engineering, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China
国际会议
The 2016 International Symposium on Safety Science and Technology(2016安全科学与技术国际会议)
昆明
英文
753-753
2016-10-17（万方平台首次上网日期，不代表论文的发表时间）