Silicon tetrachloride hydrogenation method

Abstract

The invention provides a silicon tetrachloride hydrogenation method. The method comprises the following steps: 1) heating external hydrogen gas and external silicon tetrachloride gas to a first preset temperature; 2) introducing external silicon powder and the hydrogen gas and the silicon tetrachloride gas which are heated to the first preset temperature into a first reactor, and carrying out a cold hydrogenation reaction; 3) cooling the outlet tail gas of the first reactor to a second preset temperature; 4) introducing the external silicon powder and the outlet tail gas which is cooled to the second preset temperature into a second reactor, and carrying out a trichlorosilane synthesis reaction; and 5) subjecting the outlet tail gas of the second reactor to separation treatment, heating the separated hydrogen gas and the silicon tetrachloride gas to the first preset temperature and then returning to the step 2), and conveying the separated trichlorosilane gas and a small amount of dichlorosilane gas to a downstream process. The silicon tetrachloride hydrogenation method does not need a complex reactor and can increase the yield of the existing trichlorosilane and the one-way conversion rate of the existing silicon tetrachloride.

Description

technical field [0001] The invention relates to the technical field of polysilicon production, in particular to a method for hydrogenating silicon tetrachloride. Background technique [0002] In the production process of polysilicon, regardless of the improved Siemens method or the silane method, a large amount of silicon tetrachloride will be generated. In order to avoid environmental pollution caused by silicon tetrachloride, it needs to be recycled and utilized. For example, four Silicon chloride is converted into trichlorosilane, the raw material for polysilicon production, so that the production process of polysilicon forms a closed loop. The recovery and utilization of silicon tetrachloride can not only reduce environmental pollution, but also greatly reduce production costs. [0003] At present, the recovery and treatment of silicon tetrachloride basically adopts the method of dechlorination and hydrogenation to form trichlorosilane. Among the various existing dechl...

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Problems solved by technology

[0016] The technical problem to be solved by the present invention is to provide a reactor that does not require a complex design and can improve the existing trichlorosilane yield and the existing silicon tetrachloride single-pass conversion for the above-mentioned defects in the prior art. rate of silicon tetrachloride hydrogenation method

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