Variation Law for Minimum Ignition Temperature of Coal Dust Layer

In this paper we studied the variation of the minimum ignition temperature of coal dust layer with its metamorphism, particle size and thickness using the minimum ignition temperature measurement system.The results showed that, with the gradual increase of its degree of metamorphism, the minimum ignition temperature of coal dust layer varied from 290℃ to above 400℃; and that when the coal dust layer of lignite, long flame coal, non-stick coal, gas coal were ignited, an obvious flame was observed; and that, as the coal dust particle size decreased, the minimum ignition temperature of different kinds of the coal dust layer exhibited a significant reduction trend.It was found that when the thickness of the layer is 15 mm, with the particle size decreasing from 0.5 mm to 0.075 mm, the minimum ignition temperature decreased by 31.0%, 26.7%, 28.1%, 25.8%, 28.6%, 27.8%, 18.9% and 15.0%, respectively, indicating a very obvious effect of the coal dust particle size.With the increase of the layer's thickness, the minimum ignition temperature of different kinds of the coal dust layer exhibited a decreasing trend, while the trend of anthracite was the least significant.