Fluid bed reactor

A heated silicon deposition reactor system, comprising:

• a plurality of seed particles;
• a vessel having an outer wall;
• an insulation layer facing an inner surface of the outer wall;
• at least one heater positioned inwardly of the insulation layer;
• a removable concentric liner positioned inwardly of the at least one heater, the liner having an inner surface which defines a chamber that contains the seed particles;
• a central inlet nozzle having an upper opening positioned to inject a primary gas comprising a silicon-bearing gas upwardly into the chamber, wherein the central inlet nozzle comprises an inner wall and an outer wall positioned concentrically around the inner wall to channel a flow of the primary gas through a center passageway defined by the inner wall and a flow of a secondary gas through an annular passageway between the inner wall and the outer wall;
• a plurality of fluidization nozzles, wherein each fluidization nozzle has an outlet opening into the chamber;
• at least one cooling gas nozzle opening into the chamber below the plurality of fluidization nozzles;
• and
• at least one outlet for removing silicon-coated product particles from the vessel.