Recovery system and method for trichlorosilane wet dust removal circulating liquid

Abstract

The invention belongs to the technical field of trichlorosilane production, and discloses a recovery system and method for trichlorosilane wet dust removal circulating liquid. The recovery system comprises a hydrogen chloride preheater and a synthetic furnace, wherein a gas outlet of the hydrogen chloride preheater is connected with a gas inlet of the synthetic furnace. The recovery system furthercomprises a gas flow drying tower, a catcher and a buffer tank, wherein the bottom of the gas flow drying tower is connected with the buffer tank, and a hydrogen chloride gas inlet is formed in the lower portion of the gas flow drying tower; the hydrogen chloride gas inlet is connected with a gas outlet of the hydrogen chloride preheater, the upper part of the airflow drying tower is provided with a wet dust removal circulating liquid spraying assembly, the top of the airflow drying tower is connected with a feeding hole in the lower part of the catcher, the bottom of the catcher is providedwith a discharge pipe, and a gas outlet in the top of the catcher is connected with a gas inlet of the synthesis furnace; and a discharge pipe is arranged at the bottom of the buffer tank. According to the method, chlorosilane in the wet dust removal circulating liquid can be recycled as much as possible, and the solid phase which cannot be utilized is subjected to leaching hydrolysis treatment, so the leaching load is reduced, and the influence of metal chloride on the system is also solved.

Description

technical field [0001] The invention belongs to the technical field of trichlorosilane production, and in particular relates to a recovery system and method for trichlorosilane wet dedusting circulating liquid. Background technique [0002] In recent years, with the global replacement of new energy sources and the rapid development of my country's solar photovoltaic industry, the market demand for polysilicon has grown explosively, resulting in a shortage of polysilicon. Trichlorosilane, also known as trichlorosilane, is a very important intermediate raw material in the production of polysilicon by the improved Siemens method. Trichlorosilane is also an important raw material for the production of silane coupling agents and other organosilicon compounds. [0003] At present, metallurgical-grade silicon powder and HCl gas are mainly used to produce trichlorosilane. While the main reaction is in progress, since the silicon powder contains trace amounts of metal impurities suc...

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Problems solved by technology

[0005] In the prior art, the recovery method of the wet dedusting circulating fluid is mainly through simple evaporation, and the high boiling point mixture still carrying more chlorosilanes enters the washing process. Neutralization treatment, which requires a large amount of lye, and produces a large amount of polluting gas during neutralization, and there is also a risk of explosion

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