Method and Apparatus for Preparation of Granular Polysilicon

摘要

A process for preparing granular polysilicon using a fluidized bed reactor is disclosed. The upper and lower spaces of the bed are defined as a reaction zone and a heating zone, respectively, with the height of the reaction gas outlet being selected as the reference height. The invention maximizes the reactor productivity by sufficiently providing the heat required and stably maintaining the reaction temperature in the reaction zone, without impairing the mechanical stability of the fluidized bed reactor. This is achieved through electrical resistance heating in the heating zone where an internal heater is installed in a space in between the reaction gas supplying means and the inner wall of the reactor tube, thereby heating the fluidizing gas and the silicon particles in the heating zone. The heat generated in the heating zone is transferred to the reaction zone by supplying the fluidizing gas at such a rate that the silicon particles can be intermixed between the reaction zone and the heating zone in a continuous, fluidized state.

主权项

1. A method for preparing granular polysilicon using a fluidized bed reactor, which comprises the steps of:
forming a bed of silicon particles within a reactor tube, an inner space of which comprises a heating zone and a reaction zone above the heating zone, installed within a reactor shell; supporting the bed of silicon particles with a gas distribution means that comprises a gas distribution plate or a gas distribution assembly having a plurality of holes and/or nozzles that are arranged to distribute a fluidizing gas at the bottom of the heating zone; providing a internal heater vertically in a space in between a reaction gas supplying part and the inner wall of the reactor tube, wherein the internal heater is equipped in parallel with the reaction gas supplying part both of which form intersections with the gas distribution means; performing electrical resistance heating in the heating zone using the internal heater; supplying a fluidizing gas to the reactor shell so that the fluidizing gas is introduced to the bottom of the heating zone through the cross-section of the gas distribution means except for the intersections; supplying a reaction gas to the reactor shell so that the reaction gas is introduced to the reaction zone through the reaction gas supplying means, wherein an elevation of a reaction gas outlet of the reaction gas supplying means represent a reference height for defining the heating zone and the reaction zone, and for limiting a height of the internal heater within the heating zone; and discharging an off-gas out of the fluidized bed reactor.