Research on characteristic parameters of coal-dust explosion

摘要

The parameters of explosive characteristics of the coal-dust are assessed systematically with the test device of minimum ignition temperature of dust clouds and 20L sphere explosion test units. The minimum ignition temperature of dust is a main safety index when handling combustible dusts in industrial production, and while hazard evaluation, the maximum explosion pressure and the explosion index are key parameters. Five kinds of coal-dust with different particle diameters were tested in order to determine the temperature sensitivity and the ferocity under the given conditions, which can be used as the criteria to classify dust explosion hazards. The experiment results indicate that the minimum ignition temperature of coal-dust cloud reduces with the decrease of particle diameter under temperature of (293 ± 5) K and powder spraying pressure of 0.08MPa, and when the particle size reduces to (25-48) μm, the minimum ignition temperature is between (793-803)K; Besides that, the results can also show that minimum explosive concentration of coal-dust cloud is between 20 g·m~(-3) and 30 g·m~(-3) under temperature of (293±5) K, powder spraying pressure of 2MPa and ignition energy of 10kJ, the maximum explosion pressure is 0.45MPa and the maximum explosion index is 11.14 MPa·m·s~(-1), which classifies coal-dust explosion hazards to Level I. The conclusions drawn from the experimental results are of great significance to the safe application of these combustible substances.