Research on the minimum ignition temperature variation law of coal dust cloud with different coal quality

In order to research the minimum ignition temperature variation law of coal dust cloud with different coal quality, eight coal samples including lignite, long-flame coal, non-caking coal, gas coal, charred coal, lean coal, meagre coal and anthracite were selected to analyze the minimum ignition temperature variation laws of coal dust cloud with metamorphism degree, particle size and mixing inert rock powder proportion by use of the minimum ignition temperature testing device of coal dust cloud. The research results show that: ① The lower the metamorphism degree is, the more easily the coal dust cloud in a restricted high temperature space catches fire, and the greater the potential explosion danger is. The coal dust cloud ignition process is dominated by flammable gas phase environment. ② With the particle size decreasing from 75 μm to 25 μm, the minimum ignition temperature of coal dust cloud of eight coal quality decreases continuously, and the largest drop of the minimum ignition temperature of lignite dust cloud is the largest of 18.6%, which indicates that lignite dust cloud is the most affected by particle size. The larger the air dried basis is and the smaller the particle size of coal dust is, the more easily the coal dust cloud catches fire. In "sensitive particle size range", the minimum ignition temperature of lignite dust cloud decreased the most by 8.47%. ③ Mixing inert CaCO3 rock powder with different proportions into eight coal dust has a significant inhibitory effect on coal dust cloud ignition.