Electrolytic Hydrogen Production Process and Oxygen Recovery System in Polysilicon Production

Abstract

The invention discloses an electrolytic hydrogen production process during production of polysilicon. The electrolytic hydrogen production process during the production of the polysilicon comprises the following steps of: electrolyzing alkaline solution to obtain coarse hydrogen and oxygen; allowing the coarse hydrogen to pass through a purification device; deoxidizing, dehydrating and drying thecoarse hydrogen to obtain pure hydrogen with purity of higher than 99.999 percent and oxygen at the concentration of higher than 99 percent; recovering and diluting the oxygen at the concentration ofhigher than 99 percent to obtain oxygen-enriched air with the oxygen content of 21 to 25 percent; and feeding the oxygen-enriched air into combustion equipment to perform oxygen-enriched combustion. According to the electrolytic hydrogen production process during the production of the polysilicon of the embodiment of the invention, the byproduct, namely the high-purity oxygen during electrolytic hydrogen production is recycled and not directly discharged, so energy is saved, energy consumption is reduced, and manufacturing cost of the oxygen applied to oxygen-enriched combustion is saved. Theinvention also discloses an oxygen recovery system applied to the electrolytic hydrogen production process during the production of the polysilicon.

Description

technical field [0001] The invention relates to the field of polysilicon production, in particular to an electrolytic hydrogen production process in polysilicon production and an oxygen recovery system thereof. Background technique [0002] In the polysilicon production process, hydrogen is used as the main production raw material, and the existing hydrogen production method is mainly through water electrolysis. In water electrolysis hydrogen production, the greater the amount of pure hydrogen produced, the greater the production of by-product oxygen. Specifically, while producing 1Nm3 high-purity hydrogen, it is also producing 0.5Nm3 oxygen with a concentration of 99.8%. [0003] Oxygen with more than 99.8% is a common combustion aid, oxidant and important chemical raw material in modern industry. In today's polysilicon production process, there is no recovery of oxygen, a by-product of electrolytic hydrogen production, but the oxygen is directly emptied as waste gas, res...

AI Technical Summary

Problems solved by technology

However, no matter which method is used, the preparation cost of oxygen raw material is high (4-7 yuan / Nm Oxygen), the purity is low (90-99%), and the equipment investment is large, so it is difficult to apply to industrial production

In recent years, oxygen-enriched tail gas (27-34% oxygen content) produced by cryogenic nitrogen production or pressure swing adsorption nitrogen production has also been used in oxygen-enriched combustion furnaces, but due to the low oxygen content, the required gas The flow rate is large, the volume of the recovery device is large, the investment is high, and the range of oxygen content in the air is inconvenient to adjust

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