Flow field characteristics of lignite explosion and inhibitory effect of inert powder NaCl, K2CO3, and KH2PO4

Abstract

The damage caused by coal dust explosions to safety production and public property is incalculable. To reveal the lignite explosion process and suppression, experimental and simulation studies are conducted. The results indicate that energy is released at an accelerated rate within 0.38 s after explosion, at a slowed rate within 0.38–0.62 s, and rapidly dissipated within 0.62–1 s. The explosion consumed a large amount of volatile from lignite particles, followed by moisture and fixed carbon. The error of the simulated pressure is 2.35 %, which proves the high consistency between the simulation and experimental results. The simulation found that before ignition, the lignite particles are evenly dispersed within 100 ms. After the explosion, the high temperature in the flow field spreads outwards in a circular pattern. The impact airflow is blocked by the inner wall, after the energy release is terminated, a vortex of airflow appears near the explosion source. KH₂PO₄ has a better inhibitory effect on lignite explosion than K₂CO₃, and K₂CO₃ has a better inhibitory effect than NaCl. Due to the interaction between carbonate and phosphate ions, the best inhibitory effect is achieved by mixing K₂CO₃ and KH₂PO₄. The synergistic effect of the two is of great significance for promoting industrial explosion prevention.