Process for producing trichlorosilane through inverse disporportionation of dichlorosilane

Abstract

The invention discloses a process for producing trichlorosilane through inverse disporportionation of dichlorosilane, particularly to a process for producing the trichlorosilane through inverse the disporportionation of the dichlorosilane in a polycrystalline silicon production system, and belongs to the technical field of silicon chemical industry; according to the invention, in an inverse disporportionation process of the dichlorosilane, a mixed material of liquid dichlorosilane and liquid silicon tetrachloride is adopted; a fixed-bed reactor loaded with a catalyst is adopted for reaction; and mild reaction condition, low equipment investment and less energy consumption are obtained; inverse disporportionation can be carried out on side product dichlorosilane of the polycrystalline silicon production system so as to generate the trichlorosilane, so that the production cost and treatment cost of the dichlorosilane are reduced; as a gas-liquid separating unit and a rectifying raw material product separating system are also designed in the process, the traditional processing equipment of the production system can be sufficiently utilized, and the raw material utilization rate of the polycrystalline silicon production system is increased.

Description

technical field [0001] The invention relates to a process for producing trichlorosilane by deproportionation of dichlorodihydrosilicon, in particular to a process for producing trichlorosilane by deproportionation of dichlorodihydrogensilicon in a polysilicon production system, and belongs to the technical field of silicon chemical industry. Background technique [0002] In the production process of polysilicon by the improved Siemens method, trichlorosilane and hydrogen undergo reduction reaction in the reduction furnace to generate polysilicon. Since the conversion rate of trichlorosilane in the furnace is low, a large amount of unreacted raw materials trichlorosilane and hydrogen are used as The reaction tail gas is discharged. In order to improve the utilization rate of raw materials and reduce production costs, these tail gases (mainly composed of trichlorosilane gas, silicon tetrachloride gas and hydrogen) are sent to the tail gas dry recovery system to condense the chl...

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Problems solved by technology

[0003] However, due to the complex reaction in the reduction furnace, dichlorodihydrosilane, another by-product of light components, will be produced. Dichlorodihydrosilane will enter the tail gas dry recovery system and rectification workshop in sequence with the tail gas, and finally enter the rectification tower. Top Discharge dichlorodihydrosilane to the waste gas treatment process for washing treatment by discharging low-boiling tail gas

In the large-scale polysilicon production system, the emission of dichlorodihydrosilane is large, and the tail gas of dichlorodihydrosilane is washed in the washing tower with factory domestic water, so that the dichlorodihydrogensilane gas is hydrolyzed with water to form silicon dioxide and dilute Hydrochloric acid, the silicon dioxide powder produced is processed by salvage and collection in the pool, and the dilute hydrochloric acid is neutralized by lye, and the treatment of the silicon dioxide powder collected by salvage requires a lot of manpower and material resources, which is not conducive to environmental protection; Hydrochloric acid needs to consume a large amount of lye, which is very uneconomical; at the same time, the silicon element in the light component dichlorodihydrosilane gas is lost, and it is necessary to supplement silicon powder to synthesize trichlorosilane, the raw material for polysilicon.

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