Reverse circulation fluidized bed reactor for granular polysilicon production

A reverse fluidized bed reactor (FBR) is separated by a thermally insulating vertical divider into a pre-reaction heating zone, a reaction zone, and a dehydrogenation zone. The dehydrogenation zone can be distinct, or the heating zone can serve as the dehydrogenation zone. Particles of polysilicon circulate upward through the heating zone and into the top of the reaction zone, where deposition of silicon occurs, and the grown particles slowly settle until they reenter the bottom of the pre-reaction heating zone. Dust formation, wall deposition, and hydrogen content in the product silicon particles are thereby minimized.