Trichlorosilane production method used during polycrystalline silicon production

Abstract

The invention discloses a trichlorosilane production method used during the polycrystalline silicon production. Hydrogen from a polycrystalline silicon production system, supplemented fresh hydrogen, industrial silicon powder and tetrachlorosilane generated during the polycrystalline silicon production are added into a reactor I for reaction on the premise that the reaction temperature ranges from 500 DEG C to 600 DEG C, the reaction pressure ranges from 3.5 MPa to 5.0 MPa, and the gas-phase superficial velocity is 0.1 to 2 m / s, so that tetrachlorosilane, trichlorosilane and a small amount ofdichlorosilane and chlorine hydride are generated; and after separation, tetrachlorosilane enters the reactor I for circular reactions, chlorine hydride is sent to react with silicon powder in a reactor II for reaction on the premise that the reaction temperature is 100 to 400 DEG C, the reaction pressure ranges 0.1 to 0.5 MPa, so that a chlorosilane mixture is generated, and tetrachlorosilane, high-purity trichlorosilane and dichlorosilane are respectively obtained through rectification of the chlorosilane mixture. No catalyst is added during the trichlorosilane generation process, the reaction conversion rate is maintained within 20 percent to 30 percent, the follow-up separating system burden is reduced, the reaction path of chlorine hydride is designed reasonably, the energy consumption is reduced, and the pressure is increased, and the handling ability of equipment is improved, so that the whole polycrystalline silicon production system can run stably and continuously for a long time.

Description

technical field [0001] The invention relates to a method for producing trichlorosilane, in particular to a method for producing trichlorosilane by using silicon tetrachloride and hydrogen chloride as by-products of polycrystalline silicon in the production of polycrystalline silicon. Background technique [0002] Polysilicon is used in the production of integrated circuits, electronic devices and solar cells. [0003] At present, polysilicon production enterprises have basically adopted the improved Siemens polysilicon process. A large amount of silicon tetrachloride and a small amount of hydrogen chloride are produced in this process, and there are several different methods for the recycling and utilization of silicon tetrachloride and hydrogen chloride. [0004] Patent CN 101445245A discloses a method for producing trichlorosilane from silicon tetrachloride. In this method, silicon tetrachloride with a purity of 99% after purification and hydrogen with a purity of more t...

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Problems solved by technology

[0015] In order to solve the problems in the prior art, the present invention provides a method for producing trichlorosilane in polysilicon production, which solves the problem of using polysilicon by-product silicon tetrachloride and hydrogen chloride in the prior art to produce trichlorosilane due to the addition of catalyst cost High, catalyst and by-product reaction, repeated pressurization and decompression of hydrogen chloride, energy consumption, and equipment wear and tear

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