Thermal ignition of coal powders in the presence of natural gas, oxygen and chemically active additives

At 650–750 °C, a coal powder-gas mixture containing stoichiometric amounts of natural gas and air does not burn over a surface coated with coal powder due to the inhibiting effect of gases evolving during the thermal annealing of coal powder. The ignition of the powder-gas mixture can be promoted with small amounts of a chemically active additive (e.g., dichlorosilane).