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).