Separation device and method for purifying trichlorosilane in substances with high/low boiling point

Abstract

The invention discloses a separation device and method for purifying trichlorosilane in substances with high / low boiling points. The separation device mainly comprises a raw material tank, a charging pump, a reboiler, an overhead condenser, a reflux tank, a reflux pump and an efficient distillation column; an efficient regular packing material and a sieve plate are arranged in the efficient distillation column; the number of layers of the sieve plate is 55-60; the reboiler is a horizontal type reboiler; and the overhead condenser is a floating head type condenser. According to the separation device for purifying the trichlorosilane in the substances with high / low boiling points, the boiling point of each distillation substance is increased through carrying out pressurizing distillation on a system, so that the difference among the boiling points of the substances is increased, and the efficiency for separating and purifying is more efficient. Furthermore, after purifying through the method disclosed by the invention, industrial circulating water can be used in a condensed water circulating low-temperature refrigeration system, so that the equipment investment is greatly reduced, and further, the heat-exchanging efficiency in the process is greatly increased; meanwhile, in the separation device, the floating head type condenser is used as the overhead condenser, and the horizontal type reboiler replaces a vertical type reboiler, so that the equipment failure rate and the potential safety hazard are reduced, the convention that welding places of condenser tube plates in the trichlorosilane industry are easy to leak is changed, and the service life of equipment is prolonged.

Description

technical field [0001] The invention relates to the technical field of rectification and purification, in particular to a separation device for purifying trichlorosilane in high and low boilers and a method for using the device. Background technique [0002] Trichlorosilane is also known as trichlorosilane, silicon chloroform, English name: trichlorlsilane or sili°Cochlorlform, molecular formula is SiH°L 3 It is used for the synthesis of organosilane, alkyl group, aryl group and organic functional group chlorosilane. It is the most basic monomer in organosilane coupling agent, and it is also the raw material for raw 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 bl...

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Problems solved by technology

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

[0005] Chinese patent CN1693192A 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, its quality There are still some deficiencies, and the separation efficiency of the whole process is relatively low, and the energy consumption is relatively large; Chinese patent CN1010455362A proposes a process for separating trichlorosilane with two towers, but its process is so backward that there is unstable product index, and its operation The pressure is normal pressure, so that the whole process needs a lot of freezing so that the energy consumption of the process is not large; Chinese patent CN2008100506.1 proposes a separation device and method for high-efficiency distillation and purification of trichlorosilane, but it is mainly aimed at more than 99.5% of trichlorohydrogen silicon as raw material

Therefore, at present, there is no process and device for the efficient purification and separation of trichlorosilane in high and low boilers in China.

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