Study on the Flame Propagation Characteristics of Coal Dust Explosions in Soaked and Air-Dried Conditions

Lignite was chosen as the subject of research to investigate the impact of soaked and air-dried coal dust on the microstructure of coal and the propagation characteristics of the explosion flame. Four kinds of coal samples, including raw coal, were prepared with water soaking durations of 24, 48, and 72 h. SEM observations and FTIR experiments were conducted on coal. The results show that soaked pulverized coal has a loose structure. The peak velocity of flame propagation at the exit of the Hartmann tube increased with longer soaking durations. Meanwhile, aliphatic and -OH groups increased, while the content of arene remained relatively stable. Following the explosion, the functional groups participating in the oxidation reaction increased, enhancing their oxygen adsorption capacity, leading to a strong macroscopic explosion in the early stages of the explosion. The findings of this study provide a theoretical basis for the study of coal dust explosions in underground coal mines.