Experimental investigations on explosion behaviors of large-particle and formation rules of gas residues

Using a standard 20 L spherical test vessel, the explosion characteristics of bituminous coal in the form of large particles were investigated. The goal of this research was to better understand the fundamental aspects of dust explosions and to obtain reference data for the investigation of accidental explosions. Following explosion testing, the residual gases were also analyzed by gas chromatography. The results show that large coal particles require more rigorous conditions, such as higher dust concentration and ignition energy, compared with smaller particles. Analyzing the explosion characteristics of mixtures of various particle diameters demonstrated that the addition of smaller particles dramatically increases the energy release rate and therefore increases the explosion risk of larger particles. Residue analysis showed that, with decreases in the particle size, there is an overall decline in the CO2 content together with a slight increase in CO. There were no obvious changes in the evolution of hydrocarbons with decreases in the particle size, although there were significant variations in the relative proportions of different hydrocarbons.