Laser Ignition of Microparticles of Low-Metamorphosed Coal in the Size Range 0.4–33 µM

The ignition of microparticles of low-metamorphosed (long-flame gas grade (LFGG)) coal for fractions with a distribution in the size range d = 0.4–33 µm under the action of laser pulses (1064 nm, 120 µs, 1.3 J) is studied. The coincidence of the kinetic characteristics of coal ignition under the action of laser pulses with different energy densities on samples in both narrow and wide particle size ranges is established. The minimum values of the three threshold planes of laser energy studied for the stages of ignition are obtained for the fraction of coal particles with a size of 2.2 μm. When working with coal dust, it should be taken into account that when exposed to thermal energy sources, particles of 1 to 10 microns are the most easily flammable.