The influence of the bark of wooden materials on optical-microphysical properties of pyrolysis smoke

Abstract

The variability of optical-microphysical properties of pyrolysis smokes, formed during thermal decomposition of some wooden samples (barkless birch, birch bark, and larch bark), is studied. The results of solution of the inverse problem using data from spectral nephelometric measurements have shown that the component of particles strongly absorbing radiation can be generated at comparatively low temperature of pyrolysis. The strongly absorbing fine fraction of soot particles with a radius of less than 200 nm is observed in the size spectrum of the pyrolysis smoke of birch and larch bark. The larger particles are weakly absorbing, but the imaginary part of their refraction index increases when smoke persists, because of interaction with the “soot” component. The estimates have shown that no significant differences appear in the absorption of smoke particles formed by birch and larch barks. However, the fine parts of soot particles is absent in the barkless birch smoke; i.e., the absorption of particles throughout the size range is weak.