Near-infrared radiation and scattering properties of coal fly ash particles cloud

Radiation in near infrared region dominates the heat transfer in high temperature processes including particle dispersion such as coal gasification and pulverized coal combustion. The thermal radiation properties in near-infrared region of 0.8-2.2 mu m were studied for a cloud of coal ash particles. The monochromatic absorption as well as the directional behavior of scattering for the sample particles dispersed in liquid paraffin wax were measured spectroscopically at an atmospheric state by using FT-IR. The effect of the particles number density in the cloud and the thickness of the dispersion layer on the spectrum of absorption could be expressed in the property of the extinction efficiency. The spectral distribution of the extinction efficiency is dependent of wavelength in the near-infrared region. The contribution of scattering by ash particles can be ignored, or the forward scattering dominates the particle scattering in the radiative heat transfer in the cloud.