Draft tube fluidized bed reactor for deposition of granular silicon

摘要

A granular fluidized bed reactor (FBR) for production of high purity silicon is described. The FBR uses a draft tube to promote internal circulation while minimizing voids in the fluidized bed, one significant cause of dust formation. The FBR design has geometries to minimize reactive gas concentration within the draft tube and imposes a desirable circulation pattern in operation. A portion of the FBR wall above a reactive zone provides heat input to maximize deposition on silicon beads while minimizing wall deposition. The FBR is made of carbon composite, ceramic, and graphite materials in a design to minimize contamination and enable silicon deposits to be melted out.