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Trichlorosilane tail gas recovery device and method

A technology for recovering trichlorosilane and tail gas, which is applied in separation methods, chemical instruments and methods, halogenated silanes, etc., can solve the problems of high energy consumption, large equipment investment, incomplete tail gas recovery, etc., and achieves simple process, The effect of small equipment investment and low energy consumption

Inactive Publication Date: 2012-06-13
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] Aiming at the problems of incomplete tail gas recovery, large equipment investment and high energy consumption existing in the existing process, the present invention creatively proposes the use of absorption-desorption process to recover the tail gas in the TCS production process

Method used

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  • Trichlorosilane tail gas recovery device and method
  • Trichlorosilane tail gas recovery device and method

Examples

Experimental program
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Effect test

Embodiment 1

[0028] Trichlorosilane production process tail gas, temperature -25 ° C, pressure 0.2 MPa, composition (volume percentage, the same below) is hydrogen 80-95%, hydrogen chloride 8-15%, chlorosilane 3-7%, after buffering and metering, Enter the lower part of the absorption tower 1. Ethylbenzene is used as the absorbent, and the absorbent enters from the top of the tower at -25°C, and the absorption tower adopts a packed tower for one-stage absorption. The pressure at the top of the absorption tower is 0.19MPa, the temperature at the top of the tower is -20°C, and the temperature at the bottom of the tower is 10°C. After the absorption treatment, the tail gas is recovered from the top of the absorption tower, which is analyzed and detected by gas chromatography, and the concentrations of chlorosilanes (TCS, STC, DCS) are all zero. This stream contains only hydrogen and hydrogen chloride and can be safely returned to the hydrogen chloride synthesis furnace. The absorption liquid...

Embodiment 2

[0030] Trichlorosilane production process tail gas, after two-stage compression, the pressure is 2.0MPa, the temperature is 25°C, and the composition is 85-97% hydrogen, 2-15% hydrogen chloride, and 0.1-1% chlorosilane. After buffering and metering, it enters the absorption The lower part of Tower 1. Xylene is used as the absorbent, the absorbent enters from the top of the tower, the temperature is 25°C, and the absorption tower adopts a tray tower. The pressure at the top of the absorption tower is 1.98MPa, the temperature at the top of the tower is 20°C, and the temperature at the bottom of the tower is 55°C. After the absorption treatment, the tail gas is recovered from the top of the absorption tower, and the chlorosilanes (TCS, STC, DCS) in it are all 0 by gas chromatography. This stream contains only hydrogen and hydrogen chloride and can be safely returned to the hydrogen chloride synthesis furnace. The absorption liquid is obtained at the bottom of the absorption tow...

Embodiment 3

[0032] The source of the tail gas raw material is, in addition to the tail gas described in Example 1, there is also exhaust gas from the top of the pressurized rectification tower. The temperature of the tail gas is 0°C, the pressure is 0.4MPa, and the composition is 80-90% of hydrogen, 10-20% of hydrogen chloride, and 2-6% of chlorosilane. The tail gas enters the bottom of the absorption tower, and carbon tetrachloride and toluene are used as binary absorbents. To -10 ℃ into the top of the absorption tower. The pressure at the top of the absorption tower is 0.39MPa, the temperature at the top of the tower is -5°C, and the temperature at the bottom of the tower is 35°C. The absorption tower adopts a packed tower. The pressure at the top of the desorption tower is 0.2MPa, the temperature at the top of the tower is 66-67°C, and the temperature at the bottom of the tower is 120°C. The desorption tower adopts a plate tower. All the other are with embodiment 1.

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Abstract

The invention relates to a trichlorosilane tail gas recovery device and method. An absorption tower process and a desorption tower process are adopted, tail gas enters into the absorption tower, and chlorosilane components in the tail gas is absorbed from the absorption tower through absorbent so as to enter into an absorption tower kettle to form absorption liquid. The recovered chlorosilane components in the gas cannot be detected through gas chromatography so as to form hydrogen and hydrogen chloride to be directly returned to a hydrogen chloride synthetic furnace. The absorption liquid formed by the absorbent and the chlorosilane components is adopted as feedstock to enter the desorption tower, and pure absorbent is obtained on a tower kettle and is heat exchanged to be returned to an absorbent stock tank so as to be recycled; and chlorosilane is obtained on a tower top and is returned to a rough product storage tank so as to be adopted as feedstock of a rectifying tower, and through further separation, a product trichlorosilane and a byproduct silicon tetrachloride are obtained. According to the invention, the technological process is simple, the equipment investment is small, the energy consumption is low, the complete separation of chlorosilane can be realized, and the problems of tail gas recovery and recycle during a trichlorosilane production process are thoroughly solved.

Description

technical field [0001] The invention relates to the technical field of chemical separation process, in particular to tail gas recovery in the production process of trichlorosilane. This technology is also applicable to processes such as silicon tetrachloride, organic silicon, polysilicon, etc., which have similar tail gas composition. Background technique [0002] The production process of trichlorosilane (TCS) mostly uses metallurgical grade metal silicon powder as raw material, and is obtained by reacting with hydrogen chloride gas in a fluidized bed reactor at a certain reaction temperature. Most of the reaction pressure is slightly positive pressure, and a few Use positive pressure. Depending on the reaction conditions, the composition of the synthetic reaction product is slightly different, which is basically 80-92% of trichlorosilane and 8-20% of silicon tetrachloride (STC). Impurities include a small amount of dichlorodihydrosilane (DCS), hydrogen chloride and other...

Claims

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Application Information

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IPC IPC(8): B01D53/18C01B33/107
Inventor 宋宝东余剑军
Owner TIANJIN UNIV
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