Solar flash pyrolysis of biomass direct measurement of the optical properties of biomass components

This paper reports some results of experiments made to determine optical properties of the components of biomass, mainly cellulose. Indeed, cellulose is a highly reflecting and weakly absorbing (semi transparent) material and in some experiments, a concentrated radiation is used (from solar furnaces for instance). The reflectivity is determined with a commercial reflectometer. About 85% of the incident flux is reflected by a pure cellulose pressed pellet. The subduing factor is determined with a specific experimental apparatus using optical fibers. For cellulose, about 80% of the flux which is not reflected by the surface of the pellet is absorbed after 10(-3) m. This subduing factor can be well represented by an exponential law.