Research On Dust Explosion Characteristics Of Lycopodium

Research on dust explosion provides guidance based on safety of industrial production, and to reduce the incidence of dust explosion accident provided strong guarantee. In this paper, taking lycopodium as the research object, parameters of dust explosibility and dust flame propagation parameters are the main line. In order to obtain the changing regularity of the parameters of dust explosibility with dust concentration, ignition delay, ignition energy, dusting pressure, particle size and the ignition system, the research on lycopodium by20L ball test device,1.2L Hartmann tube, the device of minimum ignition temperature of dust cloud was experimentally studied. The relevant laws were also summarized. Combined with high-speed camera and infrared thermal imaging, the propagation of lycopodium powder flame in the Hartmann tube and flame temperature were got. Specific studies are as follows:(l)Minimum ignition energy of lycopodium powder is (10-15) mJ, the optimum ignition of dust concentration is500g/m3and the optimum ignition delay time is between60ms to90ms at the dust particle size of (37.5-30) μm,which tested with Hartmann tube.(2)The limiting explosible concentration of lycopodium dust is (30-40) g/m3and the optimum ignition delay time is60ms with20L ball test device. The optimum ignition of dust concentration is500g/m3, the dust explosion pressure and the maximum explosion index are0.69MPa and17.0293MPa-m/s at the dust particle size of (37.5-30) μm. While the optimum ignition of dust concentration is750g/m3, the dust explosion pressure and the maximum explosion index are0.69MPa and17.0293MPa-m/s at the dust particle size of (50～37.5) μm. The results indicated that the explosion hazard of dust with smaller size is relatively larger. The classification of lycopodium dust explosion hazard is ascribed to Level I according to the risk classification. The effect of SiO2on dust explosion suppression were also studied, the results have shown that when the mass fraction of SiO2is20%, explosion pressure and explosion index compared with no added respectively decreased18%and22.8%. SiO2have obvious inhibitory effect on dust explosion.(3)With the minimum ignition temperature of dust cloud testing device, the minimum ignition temperature of lycopodium dust was tested for580℃thought testing different concentrations of dust ignition temperature respectively in the injection pressure of0.06MPa and0.08MPa.(4)Propagation process of lycopodium powder flame in vertical tube of Hartmann was obtained combined with Hartmann tube, high-speed camera and infrared thermal imaging. Studies have shown that the maximum height and the maximum velocity of flame propagation in a vertical tube first increases and then decreases with the increase of dust concentration. The maximum speed of the flame propagation is14.02m/s with lycopodium dust cloud concentration of500g/m3and ignition energy of800mJ. The highest temperature of lycopodium powder flame can reach1112.1℃, and the maximum flame temperature increases at first and then decreases with increasing of ignition energy.