Method and device for vaporizing hydrogen chloride in tail gas in polycrystalline silicon production

Abstract

The invention discloses a method and a device for vaporizing hydrogen chloride in tail gas in polycrystalline silicon production. The method is characterized in that: low-temperature hydrogen chloride liquid separated from the top of a hydrogen chloride separating tower exchanges heat with high-temperature chlorosilane liquid output from the bottom of the hydrogen chloride separating tower through heat exchange equipment, so that the low-temperature hydrogen chloride liquid absorbs the heat and is completely vaporized, the temperature of high-temperature chlorosilane is reduced, and chlorosilane serving as low-temperature absorption liquid enters an absorption tower to continuously absorb the hydrogen chloride in the tail gas. The device comprises a hydrogen chloride condensation storage tank, a heat exchanger and a demister, wherein a chlorosilane storage tank is arranged below the heat exchanger and connected with the heat exchanger. Heat quantity and cold quantity in a tail gas recovery system are mutually converted, so that energy is fully utilized and saved.

Description

technical field [0001] The invention relates to a method for recovering and treating tail gas produced in the industrial production of polysilicon, and more specifically relates to a method for recovering hydrogen chloride from the tail gas produced in the production of polysilicon. Background technique [0002] In polysilicon production, an important process that can recycle polysilicon production tail gas is the dry tail gas recovery system. The tail gas recovery process can recycle hydrogen, and can separate chlorosilane and hydrogen chloride in the tail gas. [0003] The main component of tail gas in polysilicon production is a large amount of hydrogen, which contains a small amount of chlorosilane and hydrogen chloride. The process is mainly through condensation, compression, absorption, desorption and adsorption processes to achieve separation and return to the device for use. The separation and recovery of hydrogen chloride can only be separated through the absorptio...

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Problems solved by technology

The traditional method is to heat and vaporize hydrogen chloride through an electric heater, which not only consumes a large amount of electric energy, but also makes it difficult to control the purity of hydrogen chloride stably, and makes the cooling capacity of the material unable to be recovered and a large amount of loss

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