System for separating and purifying trichlorosilane in production process of polysilicon and operation method thereof

Abstract

The invention provides a system for separating and purifying trichlorosilane in production process of polysilicon and an operation method thereof. The system consists of a rectification working section and a recovery refining working section; wherein, the rectification working section comprises six towers, and the recovery refining working section includes three towers; the connection mode of the six towers of the rectification working section is that a lightness-removing tower I, a lightness-removing tower II, a weight-removing tower, a secondary lightness-removing tower, a secondary weight-removing tower I and a secondary weight-removing tower II are sequentially connected with each other; the connection mode of the three towers of the recovery refining working section is that a lower-removing tower, a higher-removing tower and a product refining tower are sequentially connected with each other. Chlorsilane rectification technical equipment can be one of main technical bottlenecks limiting the production of the high-quality polysilicon material in China. The invention can achieve the separation requirements and energy-saving aim under the condition that the mass flow rate elastic ratio between feeding of the rectification working section and feeding of the recovery working section is 1:1-1:5. The rectification technique is simplified and optimized, the separation efficiency is improved, the energy consumption of rectification products is reduced, the reliability and stability of system operation can be enhanced, and the content of phosphorus, arsenic, boron and metallic contamination in the rectification products can be lowered.

Description

technical field [0001] The invention belongs to the technical field of rectification, uses a multi-tower pressurized continuous rectification process to purify trichlorosilane, and particularly proposes a trichlorosilane separation and purification system and an operation method in the polysilicon production process. Background technique [0002] Polysilicon material is the most basic, main and most important functional material in electronic information industry and solar photovoltaic power generation industry. With the rapid development of electronic information industry and solar photovoltaic new energy industry, the supply and demand of polysilicon products are seriously out of balance. Polysilicon has become a strategic material necessary for the development of my country's electronic information industry and solar photovoltaic new energy industry. The National Development and Reform Commission attaches great importance to the development of my country's polysilicon in...

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Problems solved by technology

[0004] It can be seen from the above technological process that the product quality of polysilicon is closely related to the treatment of the trichlorosilane rectification unit and the recovered chlorosilane rectification unit. In order to meet the requirements of high purity, most manufacturers use higher rectification towers, The return flow is relatively large, and its equipment investment and energy consumption are relatively high

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