Ignition of Coals with Continuous-Wave Lasers at Wavelengths of 450 and 808 nm

Abstract

The kinetic and energy characteristics of the ignition of microparticle powders of coals of G (gas), Zh (fat), and K (coking) grades with a bulk density of 0.4 g/cm3 under the action of continuous-wave laser radiation at wavelengths λ = 450 and 808 nm with an exposure time of 1 s were measured. Coals were ignited only under irradiation, and the effect of flame propagation was absent. Ignition delay times were measured as a function of the radiation power density, and the critical values of the coal ignition energy density were determined. Energy consumption for the ignition of coals with radiation at λ = 808 nm was greater than that at λ = 450 nm for all grades of coals. It was established that the absorption of laser radiation by coal samples had a quantum character.