Granular flow in a rotating cone partly submerged in a fluidized bed

When a rotating cone with supply openings near the bottom is partly inserted into a fluidized bed, solid particles are taken up and conveyed spirally over the inner surface. This principle for particle transport was used in a novel reactor for the flash pyrolysis of biomass with several distinct advantages. Particle velocities (up to 5 m/s) were measured, as well as the solids flow rate (up to 1.6 kg/s), as a function of the cone rotational velocity, cone size and cone top angle, the fluidization velocity, and the depth of the cone in the fluidized bed. Three hydrodynamic regimes were recognized, each with its own, specific flow characteristics influencing the particle residence time (distribution) on the cone wall and the solids flow rate. The transition between the regimes could be predicted using a force balance for a single particle. The particle velocity and residence time were modeled successfully for one of the regimes.