Reactive distillation purifying method and device for removing carbon-containing impurities in chlorosilane

Abstract

The intention provides a reactive distillation purifying method and device for removing carbon-containing impurities in chlorosilane, and belongs to the technical field of polycrystalline silicon production, wherein the reactive distillation tower device comprises a distillation section, a reaction section and a stripping section, the distillation section is filled with three sections of packing,the stripping section is filled with the packing, and the packing in the distillation section and the stripping section is structured packing; wherein a structural catalyst is arranged in the reactionsection, the stripping section is provided with a chlorine donor substance circulating device, a chlorosilane crude material is fed from the middle lower part of the distillation section, a chlorinedonor substance is fed from the upper part of the reaction section, and carbon-containing impurity methyl dichlorosilane in the chlorosilane crude material in the reaction section reacts with the chlorine donor under the action of the catalyst to generate high-boiling-point substance methyl trichlorosilane; the methyl trichlorosilane is finally extracted from the bottom of the tower, and high-purity chlorosilane is extracted from the side line of the middle upper part of the distillation section. The method solves the problem that the carbon-containing impurities in the chlorosilane are difficult to remove thoroughly under the existing process conditions, is simple to operate and low in investment cost, and the purity of the product chlorosilane can reach 99.999%.

Description

technical field [0001] The invention relates to a reactive distillation purification method and device for removing carbon-containing impurities in chlorosilane, a raw material for polysilicon production. Aiming at the trichlorosilane product in the conventional chlorosilane distillation process, the reactive distillation method is used to remove carbon-containing impurities, thereby obtaining High-purity chlorosilane. Background technique [0002] Polysilicon is one of the best materials for photoelectric conversion, and it is also the main material required by the electronics industry. Its demand increases rapidly with the development of photovoltaic industry and electronic information industry. It has a significant impact on the mechanical properties, especially the carbon-containing impurities, which have a significant impact on the photoelectric conversion efficiency of silicon materials or the electrical properties of electronic components. Trace amounts of carbon in ...

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Problems solved by technology

Although this patent is a method for preparing silane, the process is also to convert methyldichlorosilane into methyltrichlorosilane, so it has certain reference

[0005] Cao Lingling and others analyzed the source, separation and purification, transformation and distribution of carbon elements in each production process of polysilicon in the influencing factors and control measures of carbon mass fraction in polysilicon products, and controlled the production of chlorosilane by optimizing the purification process parameters and other measures. The content of methyldichlorosilane in the polycrystalline silicon can control the carbon mass fraction in the product polysilicon, but this method only reduces the content of carbon-containing impurities as much as possible through the optimization of process conditions, and cannot completely remove methyldichlorosilane

[0006] The method described above does not propose a perfect process and device for removing carbon-containing impurities in chlorosilane. The present invention proposes a method for preparing chlorosilane by reactive distillation. In this method, catalytic reaction and rectification are combined. The reaction and rectification are carried out simultaneously and promote each other. On the one hand, rectification enriches the reactants to improve the reaction efficiency. On the other hand, combining the two parts into one part can save investment costs.

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