On the influence of material and shape of the hot particles on the ignition characteristics of coal dust

Abstract

The multi-field coupling of coal dust ignited by hot particles of different shapes and materials has not been studied in detail, which is an important basis for understanding the multiphase ignition characteristics in the energy industry. The multi-physics coupling method is used to study the solid-gas coupling ignition characteristics. The influence of particles material and shape in a wide temperature range on the ignition characteristics of coal dust is studied. The results show that as the temperature of the hot particles decreases from 1400 K to 1100 K, the ignition delay time increases exponentially in the range of 0 s–1.8 s. The thermal energy and thermal conductivity of hot particles have a positive impact on coal dust ignition. The minimum ignition temperature is 1150 K for metallic particles and 1250 K for non-metallic particles. For the same thermal conductivity, the minimum ignition temperature is positively correlated with the thermal energy of the hot particles. In addition, as the hot particles temperature decreases, the hot spots move from the side to the top of the hot particles. The characteristics of multiphase coupling ignition under different hot particles conditions discussed have certain significance for energy security utilization.