Method and apparatus for preparing trichlorosilane through reaction rectification by using proportionate reaction

Abstract

The invention relates to a method and an apparatus for preparing trichlorosilane through reaction rectification by using proportionate reaction. The method comprises the following steps of: reacting dichlorosilane with silicon tetrachloride in the upper middle part of a reaction rectification tower, obtaining incompletely reacted dichlorosilane at the top of the reaction rectification tower; reflowing at the top of the tower and in the middle of the tower, obtaining a mixture of dichlorosilane, trichlorosilane and silicon tetrachloride at the bottom of the tower, entering a light-end removal tower to remove a light component, obtaining the dichlorosilane at the top of the light-end removal tower; reflowing to the reaction rectification tower for recycling, obtaining a mixture of trichlorosilane and silicon tetrachloride at the bottom of the tower, entering a heavy-end removal tower to separate the trichlorosilane from the silicon tetrachloride, wherein the trichlorosilane at the top of the heavy-end removal tower is a product; and taking out the silicon tetrachloride at the side line of the lower part of the tower, entering the reaction rectification tower for recycling, and obtaining excessive silicon tetrachloride at the bottom of the tower. In the invention, by utilizing the proportionate reaction, the utilization ratio of the raw materials is enhanced; the problem of dichlorosilane and silicon tetrachloride enrichment is solved; and the final conversion ratio of the dichlorosilane is ensured to reach 100 percent theoretically.

Description

technical field [0001] The invention relates to the technical field of reactive distillation, in particular to a method and equipment for preparing trichlorosilane through reactive distillation using anti-disproportionation reaction in the production process of polysilicon. Background technique [0002] Trichlorosilane is also known as trichlorosilane, silicon chloroform, English name: trichlorosilane or siliconochloroform, molecular formula is SiHCl 3 , used in the synthesis of organosilanes and alkyl, aryl and organofunctional group chlorosilanes, is the most basic monomer in organosilane coupling agents, and is also the raw material for the production of semiconductor silicon, single crystal silicon and polycrystalline silicon. [0003] Reactive distillation technology is the process of separating the product by rectification while the reaction is in progress. The principle is: for a reversible reaction, when the volatility of a certain product is greater or less than tha...

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Problems solved by technology

For silicon tetrachloride, there are methods such as cold hydrogenation to treat it, so that it can be re-converted into trichlorosilane for reuse, but the domestic technology is immature, and the amount of silicon tetrachloride to be treated is large; Dihydrosilane, although there are relatively mature technologies abroad to prepare polysilicon using it as a raw material, due to technological blockade, this field is still almost blank in China, and the boiling point of dichlorodihydrosilane is relatively low, which is relatively dangerous.

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