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Analysis of the Difference between the Harm of Coal Dust Explosion and Its Solid Residue Explosion Based on Explosion Grade and Gaseous Residue Flammability

ABSTRACT In this study, the experiments on coal dust explosion (CDE) and solid residue explosion (SRE) at different concentrations were, respectively, carried out by using a 20 L spherical explosive device. Besides, based on characteristic parameters of explosions and gaseous residues, the differences between and the harm of CDE and its SRE were analyzed. The results show that as the concentration increases, the differential rate between the maximum explosion pressure Pm and the maximum explosion pressure rise rate (dP/dt)m of SRE and that of CDE keeps decreasing. When concentration is 700 g/m3, the differential rate reaches the minimum value, namely Δd1 = 5.56% and Δd2 = 20.80%. The minimum concentration is 200 g/m3 at the CDE grade of S4 (severe), while it is 400g/m3 at the SRE grade of S4 (severe). Besides, SRE consumes less oxygen than CDE at low concentrations (100–300 g/m3), while it consumes more oxygen CDE at high concentrations (400–700 g/m3). The φ(CO)/φ(CO2) in the gas residue from SRE is smaller than one-fourth of that in the gas residue from CDE. The hydrocarbon gas in the gas residue from SRE is about three-fifths of that in the gas residue from CDE. The concentration of flammable gases in gaseous residues from CDE at the concentration range of 200–700 g/m3 can burn in air. Different from gaseous residues from CDE, the flammable range of gaseous residues from SRE is reduced to 300–500 g/m3.