Method for recovering hydrogen from tail gas produced in polysilicon production

Abstract

A method for recovering hydrogen from tail gas produced by polysilicon production, said tail gas mainly comprising hydrogen, hydrogen chloride, dichlorodihydrosilane, trichlorosilane and silicon tetrachloride, said method comprising the steps of: pressurizing and Cool the tail gas so that trichlorosilane and silicon tetrachloride become liquid, while hydrogen, hydrogen chloride, and dichlorodihydrosilane are still gaseous, so that gaseous hydrogen, hydrogen chloride, and dichlorodihydrosilane are separated by gas-liquid separation Hydrogen silicon is separated from liquid trichlorosilane and silicon tetrachloride; gaseous hydrogen, hydrogen chloride, and dichlorodihydrosilane are passed through liquid silicon tetrachloride so that gaseous hydrogen chloride and dichlorodihydrosilane are dissolved in Liquid silicon tetrachloride, thereby separating hydrogen from hydrogen chloride and dichlorodihydrosilane. The invention adopts dry treatment to recover the hydrogen in the tail gas, and can reuse it in polysilicon production, fully utilizes the raw material, reduces pollutants, solves the problem of environmental pollution, improves product quality and reduces cost.

Description

technical field [0001] The invention relates to a method for recovering and treating tail gas produced by industrial production of polysilicon, more specifically, to a method for recovering hydrogen from the tail gas produced by producing polysilicon. Background technique [0002] Polycrystalline silicon is the raw material for preparing monocrystalline silicon, which is ultimately used in the production of integrated circuits and electronic devices. It is one of the basic raw materials with the largest consumption and the highest purity requirements in the information industry. It is also a product and industry that the country encourages the development of. [0003] The world's advanced polysilicon production technology has always been monopolized by companies from the United States, Japan, and Germany. Each company has its own technical secrets and technical characteristics. After continuous research and development, it has formed its own production process. Set out, stri...

AI Technical Summary

Problems solved by technology

[0005] The outstanding feature of the traditional polysilicon production process is the tail gas wet recovery technology, that is, the tail gas in the reduction furnace is initially pressurized to separate chlorosilane and then washed with water to recover hydrogen. Due to the process of water washing, impurity gases such as oxygen and carbon dioxide in the water will be released. Contamination of hydrogen, so a large amount of recovered hydrogen needs to be purified again. During the leaching process, chlorosilane is hydrolyzed to produce sewage, which needs further treatment, resulting in environmental pollution and large material consumption.

At the same time, the hydrogen generated in the production has not been fully utilized, which not only wastes energy, but also causes environmental pollution

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