Cold Flow Studies of Rice Husk, Saw Dust, andGroundnut Shell Fuels in a Fluidized Bed

Abstract

Biomass is a low-grade energy source and must be upgraded for effectiveutilization of these residues as fuels. A fluidized bed technology permits a wide rangeof low-grade fuels of non-uniform size to be efficiently converted to other energyforms. Due to large density variations of fuel and inert solids in the bed, it is difficultto estimate hydrodynamic and mixing characteristics of the mixture in the bed. In thepresent work, three biomass fuels (i.e., rice husk, saw dust, and groundnut shells)are selected and their fluidization characteristics are estimated in the presence ofsand bed. It is observed that, for good mixing and uniform distribution of biomassfuel with bed material, size of the sand particles plays a vital role and is foundthat the sand particles of mean diameter 0.66 mm for groundnut shells and sandparticle size 0.44 mm for the other two fuels is best suited. The minimum fluidizationvelocity has been obtained from the experiential investigation for a fuel/sand two-component system and has been compared with the theoretical correlations availablein the literature. A suitable correlation to determine the minimum fluidization velocityfor the selected biomass fuels and sand mixture has been suggested.