A treatment system and method for high boilers produced in a cold hydrogenation system

Abstract

The invention discloses a treatment system and method for high boiling substances produced by a cold hydrogenation system. The treatment system comprises a polychlorosilane weight removal tower, a weight removal tower condenser, a weight removal tower reflux tank, and a weight removal tower reflux tank connected in sequence. A pump, a preheater, a polychlorosilane cracker and a chlorosilane evaporation tank, the material inlet of the polychlorosilane deweighting tower is connected to the high boiler input pipeline, and the gas outlet of the chlorosilane evaporation tank is connected to the separation tower. The polychlorosilane cracker is paved with a catalyst alkaline quaternary ammonium-based macroporous cross-linked resin, and the hydrogen chloride cracking gas is continuously introduced into the polychlorosilane cracker, and the high boilers in the polychlorosilane cracker react with the hydrogen chloride cracking gas to obtain chlorine Silane mixture. The process of the method of the invention is simple, realizes the steps of purification, cracking and separation of high boilers, avoids the impact on the environment caused by the hydrolysis of high boilers in the existing process, and the chlorosilane obtained by cracking high boilers can be used as organosilicon production The required chlorosilane raw material reduces the production cost of polysilicon.

Description

technical field [0001] The invention relates to a treatment system and method for high boilers produced by a cold hydrogenation system matched with a polysilicon production process, and belongs to the technical field of polysilicon preparation. Background technique [0002] The mainstream process of global polysilicon production adopts the modified Siemens method, which uses SiHCl 3 at high temperature H 2 Reduction precipitation in the environment forms polysilicon on the silicon core, and the tail gas H from the reduction furnace 2 , SiHCl 3 、SiCl 4 、SiH 2 Cl 2 and HCl are separated and recycled. The cold hydrogenation process supporting the improved Siemens method is to SiCl 4 , Si powder and H 2 Under the condition of 500℃ temperature and 1.5MPa pressure, it can be converted into SiHCl by catalytic reaction 3 . The crude trichlorosilane obtained by the cold hydrogenation process contains a large amount of silicon tetrachloride and a small amount of high boilers...

AI Technical Summary

Problems solved by technology

[0003] In the actual production process, 99% of the high boilers separated from the rectification column are polychlorosilanes, and their treatment is usually by concentrating and recovering a large amount of STC (SiCl 4 ) after hydrolysis with solid impurities such as metal chlorides, more chlorine is consumed

The calcium chloride produced by hydrolysis and neutralization needs to be treated with high-salt concentration process, which requires high energy consumption; the hydrochloric acid produced by hydrolysis needs to be neutralized with lye; after hydrolysis and neutralization, a large amount of silica mud is produced, which needs deep burial treatment , not only pollute the environment, but also cause a lot of waste of chlorine and Si elements, which is not conducive to the sustainable development of polysilicon production

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