Abstract
Coal dust explosion accidents often cause substantial property damage and casualties and frequently involve nano-sized coal dust. In order to study the impact of nano-sized coal on coal dust and methane–coal dust explosions, a pipe test apparatus was used to analyze the explosion pressure characteristics of five types of micro-nano particle dusts (800 nm, 1200 nm, 45 μm, 60 μm, and 75 μm) at five concentrations (100 g/m3, 250 g/m3, 500 g/m3, 750 g/m3, and 1000 g/m3). The explosion pressure characteristics were closely related to the coal dust particle size and concentration. The maximum explosion pressure, maximum rate of pressure rise, and deflagration index for nano-sized coal dust were larger than for its micro-sized counterpart, indicating that a nano-sized coal dust explosion is more dangerous. The highest deflagration index Kst for coal dust was 13.97 MPa/(m·s), indicating weak explosibility. When 7% methane was added to the air, the maximum deflagration index Kst for methane–coal dust was 42.62 MPa/(m·s), indicating very strong explosibility. This indicates that adding methane to the coal dust mixture substantially increased the hazard grade.
Highlights
Coal dust explosions are among the main hazards affecting coal mine safety (Wu et al 2011)
In order to study the impact of nano-sized coal on coal dust and methane–coal dust explosions, a pipe test apparatus was used to analyze the explosion pressure characteristics of five types of micro-nano particle dusts (800 nm, 1200 nm, 45 lm, 60 lm, and 75 lm) at five concentrations (100 g/m3, 250 g/m3, 500 g/m3, 750 g/m3, and 1000 g/m3)
The explosion pressure characteristics were closely related to the coal dust particle size and concentration
Summary
Coal dust explosions are among the main hazards affecting coal mine safety (Wu et al 2011). The violence and sensitivity of the explosion increase as the coal dust particle size. Gao et al (2010) studied the lower limit density and pressure characteristics of coal dust explosions using a 20 L spherical vessel and found that the coal dust particle size is inversely proportional to the explosion violence and sensitivity. The. Comparative study of the explosion pressure characteristics of micro- and nano-sized coal. The presence of methane, coal dust particle size reduction, and increased coal dust volatility all reduce the lower explosion limit. There are few studies on the explosion of nano-sized coal dust and methane–coal dust mixtures. Coal dust and methane–coal dust explosion experiments were conducted, and the resulting explosion pressure characteristic parameters were compared and analyzed to provide theoretical support for coal dust explosion prevention and production safety. The results show that the Mad, Aad, Vad, FC and others of coal samples are 3.9%, 8.58%, 9.37%, 78.11% and 0.04% respectively
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