Spectral-kinetic Characteristics Glow of Fat Coal at Different Stages of Laser Ignition

The spectral-kinetic characteristics of hard coal were measured at various ignition stages by a pulsed YAG:Nd³⁺-laser ( λ = 1064 nm, τi=120 μs). Three stages of ignition were established. At an energy density of H=0.8 J/cm² during the laser pulse, micro-protrusions ignite and the coal particles surface heats up to T=3500 K. At an energy density of H=1.8 J/cm² the evolvement and ignition of volatile matters take place. In the flame spectrum, at the initial instant of time, there is a glow of excited H2 molecules and CO flame. After the evolvement of volatile matters, the glow has a thermal spectrum associated with carbon particles emitted from the sample at a temperature T=2500 K. At an energy density of H=8 J/cm² ignition of the non-volatile residue is observed, the flame spectrum is thermal with a temperature T=1800 K.