Effect of methane and coal dust concentrations on explosion pressure rise

Explosion pressure rate rise (dp/dt) experiments for coal dust and methane-coal dust-air hybrid mixtures in a modified 20 L explosion apparatus were conducted to provide data on explosion characteristics in Ventilation Air Methane (VAM) systems. Coal dust concentrations of 10, 25, 50 and 100 g.m-3 ; methane concentrations of 0.75, 1.25, 2.5 and 5%; and initial ignitor energies of 1, 5 and 10 kJ were investigated. The dp/dt of dilute coal dust-methane-air hybrid mixtures were strongly affected by the ignitor energy. The potential of higher energy boosting the fuel combustion from the flammable to the explosion phase was demonstrated. There was no observed influence on dp/dt at 10 g.m-3 coal dust concentration. In contrast, 25 g.m-3 of coal dust concertation had significant influence on the dp/dt for methane-coal dust-air hybrid mixtures