System for preparing polysilicon granules in fluidized bed and process for preparing polysilicon by using same

Abstract

The invention relates to the field of polysilicon, and particularly relates to a system for preparing polysilicon granules in a fluidized bed and a process for preparing polysilicon by using the same. The system comprises a fluidized bed reactor, a cyclone separator, a fine silicon granule seed crystal tank and a silicon granule feeding tank, wherein the fluidized bed reactor comprises a fluidized bed reactor barrel and a fluidized bed expanding section; the bottom of the fluidized bed reactor barrel is provided with a product discharge outlet, the lower part of the fluidized bed reactor barrel is provided with a silicon source gas inlet and a diluting gas inlet, and the fluidized bed reactor barrel is externally wrapped with a reactor heating device; the top of the fluidized bed expanding section is provided with a reaction tail gas outlet; the top of the fine silicon granule seed crystal tank is provided with a silicon seed crystal feed inlet and a tail gas outlet; the bottom of the fluidized bed expanding section is fixedly connected with the top of the fluidized bed reactor barrel, and the diameter of the fluidized bed expanding section is greater than that of the fluidized bed reactor barrel. The system prolongs the service life of the fluidized bed reactor, saves energy, and prevents polysilicon from being contaminated by the outside; and an effect of continuous production is achieved, thereby improving the production efficiency.

Description

technical field [0001] The invention relates to the field of polysilicon, in particular to a system for preparing polysilicon particles in a fluidized bed and a process for preparing polysilicon using the system. Background technique [0002] High-purity polysilicon is an important raw material for semiconductor components and solar cells, and is the foundation of the global electronics industry and photovoltaic industry. At present, the most important method of industrially producing high-purity polysilicon is the improved Siemens method, and the polysilicon produced accounts for 70-80% of the total production in the world today. In this method, the heat-generating silicon core rod is used as the carrier of silicon deposition, and silicon-derived gas and diluent gas (such as hydrogen, etc.) are introduced at a certain temperature, and the silicon-derived gas is reduced to silicon and continuously deposited on the high-heat silicon core rod. On the surface, the diameter of ...

AI Technical Summary

Problems solved by technology

A cyclone separation is used to separate the silicon fine powder entrained in the unreacted gas, but the cyclone separator cannot separate very fine silicon powder, and there is still a large amount of silicon powder that will be taken out of the system

At the same time, the patent does not deal with the deposition of silicon powder on the reactor wall

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