Device for recovering hydrogen from exhaust gas of silicon epitaxy furnace and method for producing high-purity hydrogen

Abstract

The invention provides a device for recovering hydrogen from silicon epitaxial furnace vented tail gas and a high purity hydrogen preparation method. The high purity hydrogen preparation method utilizes a technical route of primary water washing, chemisorption deep-dechlorination, hydrogen compressor-based pressurization, PSA gas separation system-based separation, catalytic deoxidation, water cooling, terminal purification, backflow hydrogen control of front pipe pressure, renewable gas returning to the front end, purification and recovery, and explosion-proof measures so that residual microscale impurities in hydrogen are removed by 99.99999% or less and high purity hydrogen is obtained. The method realizes product hydrogen purity of 99.9-99.99999% and a recovery rate of 95%. The residual impurity chlorine, oxygen and silane amount is in a range of 1*10<-8> and can be flexibly adjusted according to product purity. The method is especially suitable for separation and recovery of hydrogen in vented tail gas in a silicon epitaxial production process and has good economic benefits and environmental protection benefits.

Description

technical field [0001] The invention belongs to the field of production and application of silicon epitaxial wafers in the electronics industry, and in particular relates to a method for preparing high-purity hydrogen by recovering hydrogen from exhaust gas of silicon epitaxial furnaces in the electronics industry. Background technique [0002] Hydrogen is a chemical raw material and a new type of clean energy. Hydrogen is used in crystal growth and substrate preparation, oxidation process, epitaxy process and chemical vapor deposition technology. The volume ratio of hydrogen in high-purity hydrogen is more than 99.9999%, and the oxygen content is less than 1×10 -6 , carbon monoxide and carbon dioxide are also less than 1×10 -6 . High-purity hydrogen is an important variety of industrial gases, widely used in chemical industry, petrochemical, petroleum, energy, electronics, metallurgy, food, machinery, aerospace, nuclear industry and many other fields. In recent years, wi...

AI Technical Summary

Problems solved by technology

[0018] The above methods are only limited to the purification of relatively pure hydrogen (purity greater than 99.9%), while the components of silicon epitaxy tail gas are relatively complex, the purity of hydrogen is low, and precise pressure control of the recovered gas is required, which requires the above Neither method satisfies the requirement

For example: the low temperature adsorption method consumes liquid nitrogen, and the scope of use is limited

High requirements for raw material pretreatment, high energy consumption and large investment in the production process

The purification effect of the metal getter method is good, but this process is a consumable material, non-renewable, and needs to be replaced regularly. At the same time, it is required that the exhaust gas should be pretreated before entering the hydrogen alloy purifier. Generally, palladium catalyst deoxidation and molecular sieve adsorption drying are used. To remove most of the oxygen, carbon monoxide, water and other impurities in the raw hydrogen

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