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

A treatment method and technology of high boiling substances, applied in the field of polysilicon preparation, can solve the problems of waste of chlorine and Si elements, unfavorable sustainable development of polysilicon production, environmental pollution, etc.

Active Publication Date: 2021-05-11
SICHUAN YONGXIANG NEW ENERGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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

Method used

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

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Effect test

Embodiment 1

[0029] The high boilers are removed from the heavy metal impurities by the weight removal tower, and then heated to 90°C by the preheater and enter the polychlorosilane cracker. The catalyst basic quaternary ammonium macroporous cross-linked resin (solid state) is laid in the polychlorosilane cracker. Cracking gas (hydrogen chloride) is introduced into the polychlorosilane cracker. The reaction temperature in the polychlorosilane cracker is 90°C and the pressure is 0.2MPa. The silane is heated and evaporated into a gas in the evaporating tank, and then separated by a separation tower to obtain silicon tetrachloride and trichlorosilane. The amount of chlorosilane obtained by the cracking reaction was tested by gas chromatography, see Table 1 below for details.

Embodiment 2

[0031] The high boilers are removed from the heavy metal impurities by the weight removal tower, and then heated to 90°C by the preheater and enter the polychlorosilane cracker. The polychlorosilane cracker is equipped with catalyst benzonitrile (liquid), and the polychlorosilane cracker is fed into Cracked gas (hydrogen gas), the reaction temperature in the polychlorosilane cracker is 90°C, the pressure is 0.2MPa, the high boiler reacts with the cracked gas to obtain a chlorosilane mixture, and the chlorosilane mixture is then input into the chlorosilane evaporation tank to be heated and evaporated into a gas And then separated by separation tower to get silicon tetrachloride and trichlorosilane. The amount of chlorosilane obtained by the cracking reaction was tested by gas chromatography, see Table 1 below for details.

Embodiment 3

[0033] The high boilers are removed from the heavy metal impurities by the weight removal tower, and then heated to 90°C by the preheater and enter the polychlorosilane cracker. The polychlorosilane cracker is equipped with a catalyst 1,6-hexamethylenediamine (liquid state), and the polychlorosilane cracks The pyrolysis gas (chlorine gas) is introduced into the polychlorosilane cracker, the reaction temperature in the polychlorosilane cracker is 90°C, the pressure is 0.2MPa, the high boiler reacts with the cracked gas to obtain a chlorosilane mixture, and the chlorosilane mixture is then input into the chlorosilane evaporation tank After heating and evaporating into a gas, it can be separated by a separation tower to obtain silicon tetrachloride and trichlorosilane. The amount of chlorosilane obtained by the cracking reaction was tested by gas chromatography, see Table 1 below for details.

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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...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/107
CPCC01B33/1071
Inventor 文德育甘居富罗周游书华彭中向春林王亚萍
Owner SICHUAN YONGXIANG NEW ENERGY CO LTD
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