Efficient and environment-friendly silicon tetrachloride tail gas recovery device

Abstract

The utility model belongs to the field of tail gas recovery devices, and particularly relates to an efficient and environment-friendly silicon tetrachloride tail gas recovery device which comprises a deep cooling unit, the deep cooling unit is connected with a deep cooling heat exchanger through a pipeline, a liquid discharging pipe is arranged on the deep cooling heat exchanger, and a condensate recovery tank is arranged at the end, away from the deep cooling heat exchanger, of the liquid discharging pipe. The outer side of the cryogenic heat exchanger is connected with a tail gas header pipe through a pipeline, and a pressure gauge is arranged on the outer side of the condensate recovery tank. According to the utility model, the dew point temperature difference between the silicon tetrachloride component in the tail gas and other components such as nitrogen, chlorine and the like is large, so that the silicon tetrachloride component in the tail gas can be liquefied in a condensation mode, the silicon tetrachloride component can be recycled, and meanwhile, the tail gas treatment cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of tail gas recovery devices, in particular to a highly efficient and environmentally friendly silicon tetrachloride tail gas recovery device. Background Art

[0002] According to the patent authorization announcement number: CN211513970U, a silicon tetrachloride tail gas direct cooling recovery device is proposed. The device cools and absorbs the tail gas through the liquid silicon tetrachloride in the absorption tank. Since the temperature of the silicon tetrachloride liquid in the absorption tank is relatively high, the recovery rate of silicon tetrachloride in the final tail gas is limited, and a large amount of silicon tetrachloride will still go to the three waste stations with the tail gas from the absorption tank.

[0003] According to the patent authorization announcement number: CN205241250U, a silicon tetrachloride distillation tail gas recovery system is proposed. The system hydrolyzes and absorbs silicon tetrachloride in the tail gas through a hydrolysis device, and does not actually recycle the silicon tetrachloride in the tail gas.

[0004] Silicon tetrachloride is a colorless, transparent, flowing liquid with a suffocating smell. It is soluble in most organic solvents such as benzene, ether, and chloroform. It is one of the most important inorganic silicon compounds. During the production or use of silicon tetrachloride, there will be continuous tail gas emissions, the main components of which are silicon tetrachloride, chlorine, nitrogen, etc. This part of the tail gas will enter the three waste stations and be leached and absorbed by alkali solution before reaching the emission standards. During the alkali solution absorption process, sodium silicate, silicon dioxide, sodium chloride and other substances will be generated to block the pipeline and spray system. At the same time, a large amount of silicon tetrachloride in the tail gas is leached and absorbed, causing great waste. Therefore, it is necessary to improve the existing technology. Utility Model Content

[0005] The utility model aims to provide an efficient and environmentally friendly silicon tetrachloride tail gas recovery device, which solves the problem that a large amount of silicon tetrachloride in the tail gas is leached and absorbed, causing great waste.

[0006] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: an efficient and environmentally friendly silicon tetrachloride tail gas recovery device, comprising a cryogenic unit, the cryogenic unit is connected to a cryogenic heat exchanger through a pipeline, a downpipe is provided on the cryogenic heat exchanger, a condensate recovery tank is provided at one end of the downpipe away from the cryogenic heat exchanger, the outer side of the cryogenic heat exchanger is connected to an exhaust main pipe through a pipeline, and a pressure gauge is provided on the outer side of the condensate recovery tank.

[0007] Preferably, a liquid sealing device is provided in the middle of the lower liquid pipe, and the liquid sealing device is located between the cryogenic heat exchanger and the condensate recovery tank. The liquid sealing device can stabilize the pressure inside the pipeline.

[0008] Preferably, a liquid level gauge is provided on the outer side of the condensate recovery tank, and the liquid level inside the condensate recovery tank can be observed by the liquid level gauge.

[0009] Preferably, the condensate recovery tank is connected to the tail gas main pipe through a pipeline, and the condensate recovery tank can recover the condensate.

[0010] Preferably, a safety valve is provided on the pipeline between the condensate recovery tank and the tail gas main pipe, and the safety valve can control the pressure inside the pipeline.

[0011] Preferably, a drain pipe is provided below the condensate recovery tank, and the condensate can be discharged through the drain pipe.

[0012] Compared with the prior art, the beneficial effects of the utility model are as follows:

[0013] The utility model has a large difference in dew point temperature between the silicon tetrachloride component in the tail gas and other components such as nitrogen and chlorine, so that the silicon tetrachloride component in the tail gas can be liquefied by condensation, so that it can be recycled and utilized, while reducing the cost of tail gas treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0015] In the figure: 101, cryogenic unit; 102, cryogenic heat exchanger; 103, condensate recovery tank; 104, tail gas main pipe; 105, downpipe; 106, liquid sealing device; 107, liquid level gauge; 108, pressure gauge; 109, safety valve; 110, drain pipe. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0017] See also Figure 1 A highly efficient and environmentally friendly silicon tetrachloride tail gas recovery device comprises a cryogenic unit 101, the cryogenic unit 101 is connected to a cryogenic heat exchanger 102 through a pipeline, a downpipe 105 is provided on the cryogenic heat exchanger 102, a condensate recovery tank 103 is provided at one end of the downpipe 105 away from the cryogenic heat exchanger 102, the outer side of the cryogenic heat exchanger 102 is connected to an tail gas main pipe 104 through a pipeline, and a pressure gauge 108 is provided on the outer side of the condensate recovery tank 103.

[0018] See also Figure 1 A liquid sealing device 106 is provided in the middle of the lower liquid pipe 105. The liquid sealing device 106 is located between the cryogenic heat exchanger 102 and the condensate recovery tank 103. The liquid sealing device 106 can stabilize the pressure inside the pipeline. A liquid level gauge 107 is provided on the outside of the condensate recovery tank 103. The liquid level inside the condensate recovery tank 103 can be observed by the liquid level gauge 107.

[0019] See also Figure 1 The condensate recovery tank 103 is connected to the exhaust gas main pipe 104 through a pipeline. The condensate recovery tank 103 can recover the condensate. A safety valve 109 is arranged on the pipeline between the condensate recovery tank 103 and the exhaust gas main pipe 104. The safety valve 109 can control the pressure inside the pipeline. A drain pipe 110 is arranged below the condensate recovery tank 103, and the condensate can be discharged through the drain pipe 110.

[0020] The specific implementation process of the utility model is as follows: a double-tube shell-and-tube cryogenic heat exchanger 102 is incorporated into the tail gas main pipe 104, the silicon tetrachloride tail gas goes through the tube side, and the refrigerant goes through the shell side. The tail gas is cooled and condensed by the refrigerant in the cryogenic heat exchanger 102, and the condensate enters the condensate recovery tank 103 through the lower liquid pipe 105 and the liquid seal device 106. The refrigerant is provided by the cryogenic device, and its temperature range is adjustable from -20 to -50°C. The cryogenic device uses high-efficiency and environmentally friendly ethylene glycol as a refrigerant. The condensate recovery tank 103 is provided with a safety valve 109, a pressure gauge 108, a liquid level gauge 107, etc., and its tail gas is connected to the tail gas pipeline after the cryogenic heat exchanger 102, and the recovered silicon tetrachloride is continuously used as a raw material;

[0021] The above heat exchanger adopts a vertical double-pass shell and tube structure, which can effectively improve the heat exchange efficiency between the refrigerant and the exhaust gas, and is convenient for the collection and discharge of condensate. A "U"-shaped liquid seal device 106 is provided on the lower liquid pipe 105 of the cryogenic heat exchanger 102, which can effectively avoid the connection effect between the cryogenic heat exchanger 102 and the recovery tank after the empty liquid, causing the exhaust gas to enter the rear system without condensation. The refrigerant temperature setting depends on the treated gas volume and the exhaust gas temperature, and its temperature range is adjustable from -20 to -50°C. When the treated gas volume is larger, the refrigerant temperature setting value is lower. The silicon tetrachloride in the condensate recovery tank 103 can be collected and reused through the drain pipe 110.

[0022] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An efficient and environmentally friendly silicon tetrachloride tail gas recovery device, comprising a cryogenic unit (101), characterized in that: The cryogenic unit (101) is connected to a cryogenic heat exchanger (102) via a pipeline, a lower liquid pipe (105) is provided on the cryogenic heat exchanger (102), a condensate recovery tank (103) is provided at one end of the lower liquid pipe (105) away from the cryogenic heat exchanger (102), the outer side of the cryogenic heat exchanger (102) is connected to an exhaust gas main pipe (104) via a pipeline, and a pressure gauge (108) is provided on the outer side of the condensate recovery tank (103).

2. A highly efficient and environmentally friendly silicon tetrachloride tail gas recovery device according to claim 1, characterized in that: A liquid sealing device (106) is provided in the middle of the lower liquid pipe (105), and the liquid sealing device (106) is located between the cryogenic heat exchanger (102) and the condensate recovery tank (103).

3. A highly efficient and environmentally friendly silicon tetrachloride tail gas recovery device according to claim 1, characterized in that: A liquid level meter (107) is provided on the outer side of the condensate recovery tank (103).

4. A highly efficient and environmentally friendly silicon tetrachloride tail gas recovery device according to claim 1, characterized in that: The condensate recovery tank (103) is connected to the tail gas main pipe (104) via a pipeline.

5. A highly efficient and environmentally friendly silicon tetrachloride tail gas recovery device according to claim 1, characterized in that: A safety valve (109) is provided on the pipeline between the condensate recovery tank (103) and the tail gas main pipe (104).

6. A highly efficient and environmentally friendly silicon tetrachloride tail gas recovery device according to claim 1, characterized in that: A drain pipe (110) is provided below the condensate recovery tank (103).

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