Separation apparatus and method of high precision rectification purify trichlorosilane

Abstract

The invention relates to a separation device which adopts the pressurized continuous high-precision distillation for extracting trichlorosilane and method thereof, including a low-boiling-point compound separation tower, a high-boiling-point compound separation tower and a hydrogen or argon pressurizing system, wherein, the feeding materials enter the middle part of the low-boiling-point compound separation tower after passing by a raw material pre-heating heat exchanger, the low-boiling-point products are separated at the tower top of the low-boiling-point compound separation tower, and a trichlorosilane forerunning product discharge pipe line at the tower bottom is connected to enter the middle part of the high-boiling-point compound separation tower. The high-purity trichlorosilane product is obtained at the tower top. The purity of the purified trichlorosilane product by the process reaches more than 99.999 percent, wherein, the content of boron, phosphorous, iron and other impurities is all less than 10ppb, the content of the impurities of the mixture of the trichlorosilane and other low-boiling-point compounds and high-boiling-point compounds is less than 5.0ppm, the recovery rate of the process is larger than 98.0 percent, meanwhile, the pressurized continuous high-precision thermal coupling distillation and separation technology of the entire invention has simple process flow and lower energy consumption.

Description

technical field [0001] The invention relates to the technical field of rectification, separation and purification, in particular to a separation device and method for high-precision rectification and purification of trichlorosilane. Background technique [0002] Trichlorosilane, also known as trichlorosilane, silicon chloroform, English name: trichlorosilane or silicon chloroform, molecular formula is SiHCl3, used in the synthesis of organosilane and alkyl, aryl and organofunctional group chlorosilanes, is the most popular organosilane coupling agent The basic monomer is also the raw material for the production of semiconductor silicon and single crystal silicon. [0003] Trichlorosilane is an important intermediate for the synthesis of organosilicon and the main raw material for the manufacture of polysilicon. With the rapid development of the organosilicon industry, there is a great demand for trichlorosilane. However, due to the restriction of foreign technology blockade...

AI Technical Summary

Problems solved by technology

At present, the German Siemens company in the world adopts atmospheric pressure separation and purification process in the purification and separation process of trichlorosilane, which is a high energy consumption process, but due to the low boiling point of trichlorosilane and its impurity compounds, the top condenser needs to use 5°C chilled water system, so the operating cost and process energy consumption of the process are very high, the equipment investment increases greatly and the process operation is complicated

[0005] Chinese patent CN 1693192A proposes a purification method and device for separating trichlorosilane in a single tower, but a small amount of light components such as boron and phosphorus in the raw material are relatively high, although it can meet the requirements of solar cell grade polysilicon, but its There are still some deficiencies in the quality, and the separation efficiency of the whole process is low and the energy consumption is relatively large; Chinese patent CN 1010455362A proposes a process for separating trichlorosilane with two towers, but the process is so backward that there is an unstable product index, and in addition Its operating pressure is normal pressure, so that the whole process requires a large amount of chilled water and the process consumes a lot of energy. Therefore, at present, there is no process and device that can efficiently purify and separate trichlorosilane in China.

[0006] The process of the present invention is aimed at the characteristics and requirements of the trichlorosilane purification process, and proposes a high-efficiency thermally coupled rectification, purification and purification of trichlorosilane separation process and its device. The purity of the purified trichlorosilane product is It can reach more than 99.999%, completely solving the problems of unreasonable design parameters, large equipment investment and energy consumption, and low separation efficiency in the existing trichlorosilane purification process

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