Silicate accumulation preventing silane tail gas leaching tower and silane tail gas treatment device

Abstract

The utility model discloses a silicane tail gas leaching tower and silicane tail gas treatment device capable of preventing silicate from accumulating, the silicane tail gas leaching tower comprises a tower kettle for temporarily storing spraying liquid, a tower body located above the tower kettle, a first spraying assembly and a demister, the first spraying assembly and the demister are both arranged on the upper portion of the tower body, and the first spraying assembly and the demister are arranged on the lower portion of the tower body. The demister is positioned above the first spraying assembly; the device further comprises a second spraying assembly and a spraying device. The second spraying assembly and the demister are arranged correspondingly so as to wash the demister to reduce accumulation of sodium silicate. The spraying device is arranged in the tower kettle and is used for spraying to the inner wall of the tower kettle so as to reduce accumulation of sodium silicate in the tower kettle.

Description

Technical Field

[0001] The utility model relates to the technical field of silane tail gas treatment, in particular to a silane tail gas scrubbing tower for preventing silicate accumulation and a silane tail gas treatment device. Background Art

[0002] In the polysilicon industry, silane gas is required for the preparation of polysilicon by the silane fluidized bed method. During the preparation of silane gas, silane tail gas is generated, and the tail gas generated by each device needs to be centrally discharged to a silane tail gas treatment device for treatment.

[0003] The current method for treating silane gas tail gas is to spray silane gas with an alkali solution such as sodium hydroxide solution. During the contact between the alkali solution and silane gas, the two undergo a chemical reaction, generating hydrogen gas that enters the atmosphere and solid waste that enters the tower, and is later discharged to a downstream device for further treatment. The main reaction of sodium hydroxide absorbing silane gas is as follows:

[0004] 2NaOH + SiH4 + H2O → Na2SiO3 + 4H2

[0005] The absorption of silane gas by sodium hydroxide is an exothermic reaction, generating sodium silicate and hydrogen gas. Among them, sodium silicate, commonly known as water glass, is an inorganic substance with the chemical formula Na2O·nSiO2. Its aqueous solution is commonly known as water glass, and solid sodium silicate is insoluble in water. When n is 1, it can be dissolved in normal temperature water. When n increases, hot water is required to dissolve it. When n is greater than 3, steam with a pressure of more than 4 atmospheres is required to dissolve it. The larger the modulus of sodium silicate, the more Si content, the greater the viscosity and bonding strength of sodium silicate, and the different degrees of polymerization of sodium silicate with different moduli. Therefore, equipment and pipelines are often blocked during the treatment of silane tail gas.

[0006] The information disclosed in this background art section is only intended to increase the understanding of the overall background of the present utility model and should not be regarded as an admission or any form of suggestion that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Utility Model

[0007] Purpose of the utility model: The technical problem to be solved by the present utility model is to provide a silane tail gas scrubbing tower for preventing silicate accumulation and a silane tail gas treatment device, which can prevent silicate from accumulating in the tower and causing equipment and pipeline blockages, aiming at the deficiencies of the prior art.

[0008] To solve the above technical problems, a first aspect of the present utility model discloses a silane tail gas scrubbing tower for preventing silicate accumulation, which includes a tower kettle for temporarily storing the spraying liquid, a tower body located above the tower kettle, a first spraying assembly and a demister. The first spraying assembly and the demister are both arranged at the upper part of the tower body, and the demister is located above the first spraying assembly; it further includes a second spraying assembly and a spraying device. The second spraying assembly is arranged corresponding to the demister to wash the demister to reduce the accumulation of sodium silicate; the spraying device is arranged in the tower kettle and is used for spraying towards the inner wall of the tower kettle to reduce the accumulation of sodium silicate in the tower kettle.

[0009] Specifically, the silane tail gas scrubbing tower includes a vent port, and the vent port is arranged at the top of the tower body.

[0010] Specifically, the silane tail gas scrubbing tower includes a tail gas inlet pipeline, and the tail gas inlet pipeline is arranged in the middle of the tower body.

[0011] Specifically, the silane tail gas scrubbing tower includes a liquid discharge port, and the liquid discharge port is arranged at the bottom end of the tower kettle.

[0012] A second aspect of the present utility model discloses a silane tail gas treatment device, which includes a spraying liquid circulation pump and the above-mentioned silane tail gas scrubbing tower for preventing silicate accumulation. The spraying liquid circulation pump is arranged outside the silane tail gas scrubbing tower. Its inlet is communicated with the tower kettle of the silane tail gas scrubbing tower to extract the spraying liquid in the tower kettle, and its outlet is respectively connected with the first spraying assembly, the second spraying assembly and the spraying device.

[0013] Specifically, the device includes a circulation pipeline. The outlet of the spraying liquid circulation pump is connected to one end of the circulation pipeline, and the other end of the circulation pipeline is connected to the first spraying assembly to realize the connection between the outlet of the spraying liquid circulation pump and the first spraying assembly.

[0014] Further, the device also includes a heat exchanger, and the heat exchanger is arranged on the circulation pipeline.

[0015] Specifically, the device includes a spraying pipeline. The spraying device is connected with the spraying pipeline, and the spraying pipeline is connected to the circulation pipeline.

[0016] Specifically, the device includes a spraying pipeline. The second spraying assembly is connected with the spraying pipeline, and the spraying pipeline is connected to the circulation pipeline.

[0017] Further, the device also includes a flow regulating valve, and the flow regulating valve is arranged on the spraying pipeline.

[0018] Beneficial effects:

[0019] 1. The silane tail gas scrubbing tower of the present utility model is provided with a second spraying assembly at the upper part of the tower body. The second spraying assembly is arranged corresponding to the demister, and can wash the demister to reduce the accumulation of sodium silicate. At the same time, a spraying device is added in the tower kettle, and the spraying device can spray to the inner wall of the tower kettle to reduce the accumulation of sodium silicate in the tower kettle.

[0020] 2. The silane tail gas treatment device of the present utility model uses a single spraying liquid circulation pump to pump the spraying liquid of the first spraying assembly, the second spraying assembly and the spraying device, simplifies the system and reduces the transformation cost. Brief Description of the Drawings

[0021] The following further detailed description of the present utility model will be made in conjunction with the drawings and specific embodiments, and the above and / or other advantages of the present utility model will become clearer.

[0022] Figure 1 It is a schematic structural diagram of a silane tail gas treatment device disclosed in an embodiment of the present utility model.

[0023] Description of the reference numerals in the drawings:

[0024] 1. Silane tail gas scrubbing tower; 11. Tower kettle; 12. Tower body; 13. First spraying assembly; 14. Demister; 15. Second spraying assembly; 16. Spraying device; 17. Venting port; 18. Tail gas inlet pipeline; 19. Drainage port; 2. Spraying liquid circulation pump; 4. Circulation pipeline; 5. Spraying pipeline; 6. Spraying pipeline; 61. Flow regulating valve; 62. Flowmeter; 7. Heat exchanger; 8. Spraying liquid. Detailed Description of the Embodiments

[0025] Embodiment 1

[0026] The silane gas is sprayed and absorbed with an alkali solution, and the generated sodium silicate will accumulate and block at the bottom of the equipment and the demister at the top over time.

[0027] Aiming at the problems of the accumulation and blockage of silicate in the tower kettle and the accumulation of silicate and silicon powder in the top demister, an embodiment of the present utility model discloses a silane tail gas scrubbing tower for preventing silicate accumulation. Refer to Figure 1 , which includes a tower kettle 11 for temporarily storing the spraying liquid 8, a tower body 12 located above the tower kettle 11, a first spraying assembly 13 and a demister 14. The first spraying assembly 13 and the demister 14 are both arranged at the upper part of the tower body 12, and the demister 14 is located above the first spraying assembly 13.

[0028] The spraying liquid 8 is an alkali solution or water. The alkali solution can be a sodium hydroxide solution with a mass concentration of 5%.

[0029] A tail gas inlet pipeline 18 is arranged in the middle of the tower body 12 of the silane tail gas scrubbing tower 1.

[0030] At the top of the tower body 12 of the silane tail gas scrubbing tower 1, an air vent 17 is provided.

[0031] At the bottom end of the tower kettle 11, a liquid discharge port 19 is provided.

[0032] During use, the process vent gas containing silane from upstream units, i.e., the silane tail gas, flows into the middle part of the tower body 12 of the silane tail gas scrubbing tower 1 through the tail gas inlet pipeline 18 and flows upward. The spray liquid sprayed by the first spray assembly 13 sprays downward to absorb the silane gas in the tail gas. The scrubbed tail gas is discharged from the air vent 17. The spray liquid 8 falls and is temporarily stored in the tower kettle 11.

[0033] To reduce the accumulation of sodium silicate, refer to Figure 1 , this silane tail gas scrubbing tower further includes a second spray assembly 15 and a spraying device 16. The second spray assembly 15 is arranged corresponding to the demister 14 to wash the demister 14 to reduce the accumulation of sodium silicate; the spraying device 16 is arranged in the tower kettle 11 and is used to spray on the inner wall of the tower kettle 11 to reduce the accumulation of sodium silicate in the tower kettle 11.

[0034] It should be understood that the spraying device 16 is preferably installed above the liquid level of the spray liquid 8 contained in the tower kettle 11.

[0035] In this embodiment, by adding a second spray assembly 15 at the upper part of the tower body, and the second spray assembly 15 is arranged corresponding to the demister 14, the demister 14 can be washed to reduce the accumulation of sodium silicate; at the same time, a spraying device 16 is added in the tower kettle 11, and the spraying device 16 can spray on the inner wall of the tower kettle 11 to reduce the accumulation of sodium silicate in the tower kettle 11.

[0036] The second aspect of the present utility model discloses a silane tail gas treatment device, refer to Figure 1 , which includes a spray liquid circulation pump 2 and the above-mentioned silane tail gas scrubbing tower 1 for preventing silicate accumulation. The spray liquid circulation pump 2 is arranged outside the silane tail gas scrubbing tower 1, and its inlet is communicated with the tower kettle 11 of the silane tail gas scrubbing tower 1 to extract the spray liquid in the tower kettle 11, and its outlet is respectively connected to the first spray assembly 13, the second spray assembly 15 and the spraying device 16.

[0037] In this embodiment, a single spray liquid circulation pump 2 is used to realize the pumping of the spray liquid of the first spray assembly 13, the second spray assembly 15 and the spraying device 16, simplifying the system and reducing the transformation cost.

[0038] Specifically, refer to Figure 1 , this device includes a circulation pipeline 4. The outlet of the spray liquid circulation pump 2 is connected to one end of the circulation pipeline 4, and the other end of the circulation pipeline 4 is connected to the first spray assembly 13 to realize the connection between the outlet of the spray liquid circulation pump 2 and the first spray assembly 13.

[0039] Further, referring to Figure 1 , the device further includes a heat exchanger 7, and the heat exchanger 7 is arranged on the circulation pipeline 4.

[0040] In this embodiment, the heat exchanger 7 is used to heat the spraying liquid flowing to the first spraying assembly 13, such as alkali liquid, so as to meet the solution temperature requirement for washing the silane tail gas in the scrubbing tower.

[0041] Specifically, referring to Figure 1 , the device includes an injection pipeline 5, the injection device 16 is connected with the injection pipeline 5, and the injection pipeline 5 is connected to the circulation pipeline 4.

[0042] Specifically, referring to Figure 1 , the device includes a spraying pipeline 6, the second spraying assembly 15 is connected with the spraying pipeline 6, and the spraying pipeline 6 is connected to the circulation pipeline 4.

[0043] Further, referring to Figure 1 , the device further includes a flow regulating valve 61, and the flow regulating valve 61 is arranged on the spraying pipeline 6. The flow regulating valve 61 can be a pneumatic valve.

[0044] In this embodiment, the flow of the second spraying assembly 15 for washing the demister 14 is controlled by setting the flow regulating valve 61. In a specific embodiment, the second spraying assembly 15 includes two groups of spray heads, which are respectively arranged above and below the demister 14, and each group of spray heads includes a plurality of evenly distributed spray heads to ensure that the spraying liquid, such as alkali liquid or hot water, is evenly sprayed on the demister 14. The flow of each spray head is controlled at 5 - 10 m3 / h.

[0045] Further, referring to Figure 1 , the device further includes a flowmeter 62 for measuring the flow of the spraying liquid in the spraying pipeline 6, and the flowmeter 62 is arranged on the spraying pipeline 6 and upstream of the flow regulating valve 61.

[0046] The present invention provides an idea and method for a silane tail gas scrubbing tower and a silane tail gas treatment device for preventing silicate accumulation. There are many methods and ways to specifically implement this technical solution. The above description is only a preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention. Each component not clearly defined in this embodiment can be implemented by existing technologies.

Claims

1. A silane tail gas scrubbing tower for preventing silicate accumulation, characterized in that, It includes a reboiler (11) for temporarily storing the spraying liquid (8), a tower body (12) located above the reboiler (11), a first spraying assembly (13) and a demister (14). The first spraying assembly (13) and the demister (14) are both arranged at the upper part of the tower body (12), and the demister (14) is located above the first spraying assembly (13). It further includes a second spraying assembly (15) and a spraying device (16). The second spraying assembly (15) is arranged corresponding to the demister (14). The spraying device (16) is arranged in the reboiler (11).

2. The silane tail gas scrubbing tower according to claim 1, wherein, It includes a vent port (17), and the vent port (17) is arranged at the top of the tower body (12).

3. The silane tail gas scrubbing tower according to claim 2, wherein It includes a tail gas inlet pipeline (18), and the tail gas inlet pipeline (18) is arranged in the middle of the tower body (12).

4. The silane tail gas scrubbing tower according to claim 3, wherein It includes a liquid discharge port (19), and the liquid discharge port (19) is arranged at the bottom end of the reboiler (11).

5. A silane tail gas treatment device, characterized in that, It includes a spraying liquid circulation pump (2) and a silane tail gas scrubbing tower (1) for preventing silicate accumulation as claimed in claim 1. The spraying liquid circulation pump (2) is arranged outside the silane tail gas scrubbing tower (1). Its inlet is communicated with the reboiler (11) of the silane tail gas scrubbing tower (1) to extract the spraying liquid in the reboiler (11), and its outlet is respectively connected with the first spraying assembly (13), the second spraying assembly (15) and the spraying device (16).

6. The silane tail gas treatment device according to claim 5, wherein It includes a circulation pipeline (4). The outlet of the spraying liquid circulation pump (2) is connected with one end of the circulation pipeline (4), and the other end of the circulation pipeline (4) is connected with the first spraying assembly (13) to realize the connection between the outlet of the spraying liquid circulation pump (2) and the first spraying assembly (13).

7. The silane tail gas treatment device according to claim 6, wherein, It further includes a heat exchanger (7), and the heat exchanger (7) is arranged on the circulation pipeline (4).

8. The silane tail gas treatment device according to claim 6, wherein, It includes a spraying pipeline (5). The spraying device (16) is connected with the spraying pipeline (5), and the spraying pipeline (5) is connected to the circulation pipeline (4).

9. The silane tail gas treatment device according to claim 6, characterized in that, It includes a spraying pipeline (6). The second spraying assembly (15) is connected with the spraying pipeline (6), and the spraying pipeline (6) is connected to the circulation pipeline (4).

10. The silane tail gas treatment device according to claim 9, wherein It further includes a flow regulating valve (61), and the flow regulating valve (61) is arranged on the spraying pipeline (6).

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