Silicon powder adding system

Abstract

The utility model provides a silicon powder adding system which comprises a silicon powder storage tank, a silicon powder feeding device, a silicon powder feeding device and a silicon powder feeding device. The elevator is provided with a material receiving opening and a material discharging opening, the position of the material discharging opening is higher than that of the material receiving opening, and the material receiving opening is connected with a material outlet of the silicon powder storage tank; the low-pressure stock bin is arranged below the discharge port and is used for receiving the silicon powder discharged from the discharge port; the low-pressure stock bin is connected with a first nitrogen pipeline; the high-pressure stock bin is arranged below the low-pressure stock bin, is connected with a discharge port of the low-pressure stock bin and is used for enabling the silicon powder subjected to nitrogen replacement in the low-pressure stock bin to enter the high-pressure stock bin; the high-pressure stock bin is connected with a first hydrogen pipeline; and a discharge port of the high-pressure stock bin is connected to the reactor, so that the qualified silicon powder after replacement enters the reactor. According to the silicon powder adding system, abrasion and blockage of the pipeline in the silicon powder conveying process can be avoided, the maintenance and replacement period and frequency of the pipeline are reduced, and production continuity is guaranteed.

Description

Technical Field

[0001] The present application belongs to the technical field of polysilicon production, and in particular relates to a silicon powder adding system for a cold hydrogenation device. Background Art

[0002] The cold hydrogenation device is the "core" unit of polysilicon production. Its main principle is to heat silicon tetrachloride and hydrogen to a certain temperature through heat exchange, and then undergo gas-solid phase reaction with silicon powder in a fluidized bed reactor.

[0003] The production process requires continuous delivery of silicon powder to the fluidized bed reactor. The traditional way of adding silicon powder is to manually lift the silicon powder bag to the top of the silicon powder storage tank via an overhead crane and flow the silicon powder into the silicon powder storage tank. This method requires a lot of manpower and the overall efficiency is not high.

[0004] Another method of adding silicon powder is pneumatic conveying, which uses a gas (usually nitrogen) as a carrier to transport the silicon powder through a pipeline using a certain pressure differential. The nitrogen fluidizes the silicon powder, forming a gas-solid two-phase flow, allowing it to flow through the pipeline and ultimately be transported to the desired location. However, due to the high hardness of silicon powder (around 7 on the Mohs scale), this method causes significant wear and tear on the conveying pipeline, requiring regular maintenance and replacement, increasing production costs. Furthermore, the complex flow characteristics of the gas-solid two-phase flow during the conveying process can easily lead to pipeline blockage and other problems, affecting production continuity. Utility Model Content

[0005] In response to the above-mentioned technical problems existing in the prior art, an embodiment of the present application provides a silicon powder adding system, which aims to solve the technical problems existing in the above-mentioned background technology.

[0006] The technical solution adopted in the embodiment of the present application is: a silicon powder adding system, comprising:

[0007] A silicon powder storage tank having a feed port and a discharge port;

[0008] An elevator having a receiving port and a discharge port, wherein the discharge port is located higher than the receiving port, and the receiving port is connected to the discharge port of the silicon powder storage tank, so that the silicon powder in the silicon powder storage tank can enter the elevator through the receiving port and be discharged from the discharge port;

[0009] a low-pressure silo, disposed below the discharge port, for receiving the silicon powder discharged from the discharge port; a first nitrogen pipeline connected to the low-pressure silo, for filling the low-pressure silo with nitrogen to displace the air therein;

[0010] A high-pressure silo is arranged below the low-pressure silo and connected to the discharge port of the low-pressure silo, so as to allow the silicon powder after nitrogen replacement in the low-pressure silo to enter the high-pressure silo; a first hydrogen pipeline is connected to the high-pressure silo, and the first hydrogen pipeline is used to fill hydrogen into the high-pressure silo to replace the nitrogen therein; the discharge port of the high-pressure silo is connected to the reactor, so that the silicon powder after qualified replacement can enter the reactor.

[0011] In an optional embodiment, the elevator is a Z-type bucket elevator and includes a first transverse transport section, a second transverse transport section and a vertical transport section. The first transverse transport section is located obliquely above the second transverse transport section, one end of the first transverse transport section is connected to the upper end of the vertical transport section, and the first transverse transport section is provided with the unloading port near the other end thereof; one end of the second transverse transport section is connected to the lower end of the vertical transport section, and the second transverse transport section is provided with the receiving port near the other end thereof.

[0012] In an optional embodiment, the silicon powder adding system further includes a silicon powder filter, which is connected to the exhaust gas outlet of the high-pressure silo near the top thereof, so that the exhaust gas in the high-pressure silo enters the silicon powder filter for filtration and the silicon powder in the exhaust gas is recovered.

[0013] In an optional embodiment, a second hydrogen pipeline is connected to the silicon powder filter, and the second hydrogen pipeline is used to deliver hydrogen to the bottom of the silicon powder filter so that the silicon powder in the silicon powder filter can flow smoothly into the high-pressure silo.

[0014] In an optional embodiment, the first hydrogen pipeline and the second hydrogen pipeline are respectively connected to a second nitrogen pipeline, and the second nitrogen pipeline is used to supply nitrogen to the silicon powder filter, the high-pressure silo and its pipeline through the first hydrogen pipeline and the second hydrogen pipeline respectively to blow out the hydrogen therein.

[0015] In an optional embodiment, the silicon powder adding system further includes a vent filter, which is connected to the exhaust gas outlet of the low-pressure silo near the top thereof, so that the exhaust gas in the low-pressure silo enters the vent filter for filtration and then is discharged.

[0016] In an optional embodiment, a third nitrogen pipeline is connected to the vent filter, and the third nitrogen pipeline is used to deliver nitrogen to the bottom of the vent filter so that the silicon powder in the vent filter can flow smoothly into the low-pressure silo.

[0017] In an optional embodiment, the exhaust gas outlet of the low-pressure silo is connected to the middle and lower part of the vent filter through an exhaust gas pipe; a dust outlet is provided at the top of the silicon powder storage tank, and the dust outlet is connected to the exhaust gas pipe through a dust pipe, so that the dust in the silicon powder storage tank enters the vent filter for filtration.

[0018] In an optional embodiment, the discharge port of the silicon powder storage tank and the receiving port of the elevator are connected by a first metal pipe; and / or

[0019] The discharge port of the elevator and the feed port of the low-pressure silo are connected via a second metal pipe; and / or

[0020] The discharge port of the low-pressure silo and the feed port of the high-pressure silo are connected via a third metal pipe, and a plurality of shut-off valves are provided on the third metal pipe; the third metal pipe is connected to a fourth nitrogen pipe.

[0021] In an optional embodiment, the silicon powder adding system further comprises a silicon powder tanker, wherein the silicon powder tanker is connected to the silicon powder storage tank and is used to provide silicon powder to the silicon powder storage tank; and / or

[0022] The silicon powder storage tank is connected to a fifth nitrogen pipeline near its bottom, and the fifth nitrogen pipeline is used to deliver nitrogen into the bottom of the silicon powder storage tank so that the silicon powder in the silicon powder storage tank can flow smoothly into the receiving port of the elevator.

[0023] Compared with the prior art, the beneficial effects of the embodiments of the present application are: the silicon powder adding system of the present application can avoid wear and blockage of the pipeline during the silicon powder transportation process, reduce the maintenance and replacement cycle and frequency of the pipeline, and ensure production continuity.

[0024] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention.

[0025] This application describes an overview of various implementations or examples of the technology, and is not a comprehensive disclosure of the full scope or all of the features of the disclosed technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In the drawings, which are not necessarily drawn to scale, like reference numerals may describe similar components in different views. The drawings illustrate various embodiments generally by way of example and not limitation, and together with the description and claims, serve to illustrate the disclosed embodiments. Where appropriate, like reference numerals are used throughout the drawings to refer to like or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive of the embodiments of the present apparatus or method.

[0027] Figure 1This is a schematic structural diagram of a silicon powder adding system according to an embodiment of the present application.

[0028] Reference numerals:

[0029] 1-Silicon powder storage tank; 2-Elevator; 3-Low-pressure silo; 4-High-pressure silo; 5-Silicon powder filter; 6-Vent filter; 7-Silicon powder tank truck; 8-Receiving port; 9-Discharging port; 10-First nitrogen pipeline; 11-Second nitrogen pipeline; 12-Third nitrogen pipeline; 13-Fourth nitrogen pipeline; 14-Fifth nitrogen pipeline; 15-First hydrogen pipeline; 16-Second hydrogen pipeline; 17-First metal pipeline; 18-Second metal pipeline; 19-Third metal pipeline; 20-First return pipeline; 21-Second return pipeline; 22-Exhaust pipeline; 23-Dust pipeline; 24-Feeding pipeline; 25-Shut-off valve. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0031] Unless otherwise defined, the technical or scientific terms used in this application should have the usual meanings understood by people with ordinary skills in the field to which this application belongs. The "first", "second" and similar words used in this application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0032] In order to keep the following description of the embodiments of the present application clear and concise, detailed descriptions of known functions and known components are omitted in this application.

[0033] An embodiment of the present application provides a silicon powder adding system for delivering silicon powder into a reactor of a cold hydrogenation device.

[0034] like Figure 1As shown, the silicon powder adding system of the embodiment of the present application includes a silicon powder storage tank 1, an elevator 2, a low-pressure silo 3 and a high-pressure silo 4. The silicon powder storage tank 1 has a feed port and a discharge port; the elevator 2 has a receiving port 8 and a discharge port 9, and the position of the discharge port 9 is higher than the position of the receiving port 8. The receiving port 8 is connected to the discharge port of the silicon powder storage tank 1, so that the silicon powder in the silicon powder storage tank 1 can enter the elevator 2 through the receiving port 8, and finally be discharged from the discharge port 9 as the elevator 2 rises. The low-pressure silo 3 is arranged below the discharge port 9 to receive the silicon powder discharged from the discharge port 9; the low-pressure silo 3 is connected to a first nitrogen pipeline 10, which is used to fill nitrogen into the low-pressure silo 3 to replace the air therein. The high-pressure silo 4 is arranged below the low-pressure silo 3 and is connected to the discharge port of the low-pressure silo 3, so as to allow the silicon powder after nitrogen replacement in the low-pressure silo 3 to enter the high-pressure silo 4; the high-pressure silo 4 is connected to a first hydrogen pipeline 15, which is used to fill hydrogen into the high-pressure silo 4 to replace the nitrogen therein; the discharge port of the high-pressure silo 4 is connected to the reactor so that the silicon powder after qualified replacement can enter the reactor.

[0035] The silicon powder adding system of the embodiment of the present application can reduce labor intensity, improve transportation efficiency, and replace the silo pump transportation with the hoist 2, etc., which can solve the problem that the pipeline in the existing transportation process is easily worn and blocked.

[0036] In some embodiments, the elevator 2 is a Z-type bucket elevator, which includes a first transverse transport section, a second transverse transport section, and a vertical transport section. The first transverse transport section is located obliquely above the second transverse transport section, one end of the first transverse transport section is connected to the upper end of the vertical transport section, and the first transverse transport section is provided with a discharge port 9 near its other end; one end of the second transverse transport section is connected to the lower end of the vertical transport section, and the second transverse transport section is provided with a receiving port 8 near its other end. The Z-type bucket elevator has a large transport capacity, a high lifting height, stable and reliable operation, and can effectively reduce the floor space occupied while lifting the same height.

[0037] It can be understood that a hopper is arranged on the Z-type bucket elevator, and the hopper is transported from the receiving port 8 of the elevator 2 along the transportation section to the discharge port 9, so as to transport the silicon powder from the low position of the elevator 2 to the high position of the elevator 2 and unload it into the low-pressure silo 3.

[0038] like Figure 1 As shown, the receiving port 8 of the elevator 2 opens upward and is funnel-shaped with a large upper end and a small lower end to facilitate the reception of silicon powder. The discharge port 9 of the elevator 2 opens downward and is funnel-shaped with a large upper end and a small lower end to prevent dust from being generated during the discharge process.

[0039] like Figure 1As shown, the discharge port of the silicon powder storage tank 1 and the receiving port 8 of the elevator 2 are connected by a first metal pipe 17, which is equipped with a shutoff valve 25. The metal pipe improves wear resistance and extends the service life of the pipe. The shutoff valve 25 is used to control the opening and closing of the first metal pipe 17, thereby controlling whether the silicon powder in the silicon powder storage tank 1 is delivered to the elevator 2.

[0040] Continue to combine Figure 1 The discharge port 9 of the elevator 2 and the feed port of the low-pressure silo 3 are connected by a second metal pipe 18, which is equipped with a shutoff valve 25. The metal pipe improves wear resistance and extends the service life of the pipe. The shutoff valve 25 can control the on-off of the second metal pipe 18 to control whether the material is fed to the low-pressure silo 3. The shutoff valve 25 can also isolate the low-pressure silo 3 from other devices, meeting the need to isolate the low-pressure silo 3 under certain operating conditions.

[0041] In some embodiments, as Figure 1 As shown, the silicon powder addition system also includes a silicon powder filter 5, which is connected to the exhaust gas outlet near the top of the high-pressure silo 4. This allows the exhaust gas from the high-pressure silo 4 to enter the silicon powder filter 5 for filtration and recovery of the silicon powder in the exhaust gas. The silicon powder filter 5 not only filters the exhaust gas from the high-pressure silo 4, preventing direct discharge and environmental pollution, but also recovers the silicon powder in the exhaust gas, avoiding material waste. The recovered silicon powder can be returned to the high-pressure silo 4 through the first return pipe 20 to continue participating in the hydrogen exchange.

[0042] In some embodiments, continued binding Figure 1 The silicon powder filter 5 is connected to a second hydrogen pipeline 16, which is used to supply hydrogen to the bottom of the silicon powder filter 5 so that the silicon powder in the silicon powder filter 5 can flow smoothly into the high-pressure silo 4. Since the silicon powder recovered by the silicon powder filter 5 is mainly located near the bottom of the silicon powder filter 5, the second hydrogen pipeline 16 can be connected to a position near the bottom of the silicon powder filter 5. This not only does not affect the filtering operation of the silicon powder filter 5, but also facilitates blowing the silicon powder into the first return pipeline 20 and into the high-pressure silo 4.

[0043] like Figure 1 As shown, the first hydrogen pipeline 15 and the second hydrogen pipeline 16 are respectively connected to the second nitrogen pipeline 11. The second nitrogen pipeline 11 is used to supply nitrogen to the silicon powder filter 5, the high-pressure silo 4 and their corresponding pipelines through the first hydrogen pipeline 15 and the second hydrogen pipeline 16, respectively, so as to blow out the hydrogen therein during maintenance work, thereby facilitating the smooth progress of the maintenance work.

[0044] In some embodiments, as Figure 1As shown, the silicon powder adding system also includes a vent filter 6, which is connected to the exhaust outlet near the top of the low-pressure silo 3, so that the exhaust gas in the low-pressure silo 3 enters the vent filter 6 for filtration before being discharged. By providing the vent filter 6, not only can the exhaust gas from the low-pressure silo 3 be filtered to prevent direct discharge and environmental pollution, but the silicon powder in the exhaust gas can also be recovered to avoid material waste. The recovered silicon powder can be returned to the low-pressure silo 3 through the second return pipe 21 to continue participating in the nitrogen replacement.

[0045] Continue to combine Figure 1 The vent filter 6 is connected to a third nitrogen pipe 12, which is used to supply nitrogen to the bottom of the vent filter 6, so that the silicon powder in the vent filter 6 can flow smoothly into the low-pressure silo 3. Since the silicon powder recovered by the vent filter 6 is mainly located near the bottom of the vent filter 6, the third nitrogen pipe 12 can be connected to a position near the bottom of the vent filter 6. This not only does not affect the filtering operation of the vent filter 6, but also facilitates blowing the silicon powder into the second return pipe 21 and into the low-pressure silo 3.

[0046] like Figure 1 As shown, the discharge port of the low-pressure silo 3 and the feed port of the high-pressure silo 4 are connected via a third metal pipe 19, which is provided with a plurality of shut-off valves 25. The provision of a metal pipe improves wear resistance and extends the service life of the pipe. The shut-off valve 25 can control the on-off of the third metal pipe 19 to control whether the silicon powder in the low-pressure silo 3 is transported to the high-pressure silo 4. In addition, the provision of multiple shut-off valves 25 can prevent one of the shut-off valves 25 from being loosely closed or leaking due to wear of the silicon powder. Alternatively, another shut-off valve 25 can be used to shut off the pipe, preventing hydrogen from the high-pressure silo 4 from entering the low-pressure silo 3 and ensuring the safety of the system.

[0047] Furthermore, the third metal pipe 19 is connected to a fourth nitrogen pipe 13 , and the fourth nitrogen pipe 13 is used to supply nitrogen into the third metal pipe 19 to ensure smooth flow of silicon powder.

[0048] In some embodiments, as Figure 1 As shown, the tail gas outlet of low-pressure silo 3 is connected to the lower middle portion of vent filter 6 via tail gas pipe 22. A dust outlet is provided at the top of silicon powder storage tank 1, which is connected to tail gas pipe 22 via dust pipe 23. This allows dust within silicon powder storage tank 1 to enter vent filter 6 for filtration. This allows silicon powder to be recovered from the dust within silicon powder storage tank 1, avoiding waste.

[0049] In some embodiments, as Figure 1As shown, the silicon powder adding system further includes a silicon powder tanker 7, which is connected to the silicon powder storage tank 1 and is used to supply silicon powder to the silicon powder storage tank 1. Specifically, the silicon powder tanker 7 and the silicon powder storage tank 1 can be connected via a feeding pipe 24. The lower end of the feeding pipe 24 is connected to the bottom discharge port of the silicon powder tanker 7, and the upper end of the feeding pipe 24 is connected to the top feed port of the silicon powder storage tank 1. The feeding pipe 24 is provided with a feeding pump. Under the action of the pump, the silicon powder in the silicon powder tanker 7 enters the silicon powder storage tank 1 from the top of the silicon powder storage tank 1.

[0050] Furthermore, a fifth nitrogen pipeline 14 is connected to the bottom of the silicon powder storage tank 1 , and the fifth nitrogen pipeline 14 is used to supply nitrogen into the bottom of the silicon powder storage tank 1 so that the silicon powder in the silicon powder storage tank 1 can flow smoothly into the receiving port 8 of the elevator 2 .

[0051] It is understandable that the pressure of nitrogen in each nitrogen pipeline can be selected and determined as needed. In this application, the pressure of nitrogen can be 0.6 MPa.

[0052] like Figure 1 As shown, the silicon powder feeding system of the present embodiment can be equipped with two silicon powder conveying lines, namely Line A and Line B, for the silicon powder storage tank 1. Line A and Line B are identical, sharing a silicon powder storage tank 1 and a silicon powder tanker 7. Both lines also include an elevator 2, a low-pressure silo 3, and a high-pressure silo 4, which are arranged in sequence. The discharge port of the silicon powder storage tank 1 is connected to two first metal pipes 17, one of which is connected to Line A and the other to Line B. This can improve the transportation capacity of the silicon powder feeding system and the production capacity of polysilicon.

[0053] The following combination Figure 1 The operation process of the silicon powder adding system of the embodiment of the present application is described as follows:

[0054] The silicon powder is first transported from the silicon powder tanker 7 to the silicon powder storage tank 1. One silicon powder storage tank 1 can be used to supply Line A and Line B (taking Line A as an example). The silicon powder in the silicon powder storage tank 1 flows to the receiving port 8 at the lower part of the elevator 2. As the elevator 2 runs, the silicon powder is lifted to the discharge port 9 at the higher part. After being discharged from the discharge port 9, the silicon powder enters the low-pressure silo 3 (the pressure in the low-pressure silo 3 is generally 0.5-0.6 MPa). Nitrogen replacement is performed in the low-pressure silo 3. The exhaust gas after replacement is filtered by the vent filter 6 and then discharged. The silicon powder filtered by the vent filter 6 returns to the low-pressure silo 3. The silicon powder that has been replaced and qualified in the pressure silo 3 enters the high-pressure silo 4 (the pressure in the high-pressure silo 4 is generally 2.5-3.0 MPa) through the third metal pipe 19; the silicon powder undergoes hydrogen replacement in the high-pressure silo 4, and the exhaust gas after replacement has a high hydrogen content, so it is filtered through the silicon powder filter 5 and discharged from the top of the silicon powder filter 5 and can be recycled; the silicon powder filtered out by the silicon powder filter 5 can be returned to the high-pressure silo 4 for use; after the silicon powder in the high-pressure silo 4 passes the hydrogen replacement, hydrogen is continuously added to the high-pressure silo 4 to increase the pressure, and the silicon powder flows into the reactor. The silicon powder adding system of the present application overcomes the shortcomings of the existing technology and solves the problem that the pipeline is easily worn and blocked during the silicon powder transportation process.

[0055] The above description is intended to be illustrative rather than restrictive, and those skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present disclosure. Furthermore, the above examples (or one or more of them) may be used in combination with each other, and it is contemplated that these embodiments may be combined with each other in various combinations or permutations.

Claims

1. A silicon powder adding system, characterized in that: include: A silicon powder storage tank having a feed port and a discharge port; An elevator having a receiving port and a discharge port, wherein the discharge port is located higher than the receiving port, and the receiving port is connected to the discharge port of the silicon powder storage tank, so that the silicon powder in the silicon powder storage tank can enter the elevator through the receiving port and be discharged from the discharge port; a low-pressure silo, disposed below the discharge port, for receiving the silicon powder discharged from the discharge port; a first nitrogen pipeline connected to the low-pressure silo, for filling the low-pressure silo with nitrogen to displace the air therein; A high-pressure silo is arranged below the low-pressure silo and connected to the discharge port of the low-pressure silo, so as to allow the silicon powder after nitrogen replacement in the low-pressure silo to enter the high-pressure silo; a first hydrogen pipeline is connected to the high-pressure silo, and the first hydrogen pipeline is used to fill hydrogen into the high-pressure silo to replace the nitrogen therein; the discharge port of the high-pressure silo is connected to the reactor, so that the silicon powder after qualified replacement can enter the reactor.

2. The silicon powder adding system according to claim 1, characterized in that: The elevator is a Z-type bucket elevator and includes a first transverse transport section, a second transverse transport section and a vertical transport section. The first transverse transport section is located obliquely above the second transverse transport section, one end of the first transverse transport section is connected to the upper end of the vertical transport section, and the first transverse transport section is provided with the unloading port near the other end thereof; one end of the second transverse transport section is connected to the lower end of the vertical transport section, and the second transverse transport section is provided with the receiving port near the other end thereof.

3. The silicon powder adding system according to claim 1, characterized in that: The silicon powder adding system further includes a silicon powder filter, which is connected to the tail gas outlet of the high-pressure silo near the top thereof, so that the tail gas in the high-pressure silo enters the silicon powder filter for filtration and recovers the silicon powder in the tail gas.

4. The silicon powder adding system according to claim 3, characterized in that: The silicon powder filter is connected to a second hydrogen pipeline, and the second hydrogen pipeline is used to supply hydrogen to the bottom of the silicon powder filter, so that the silicon powder in the silicon powder filter can flow smoothly into the high-pressure silo.

5. The silicon powder adding system according to claim 4, characterized in that: The first hydrogen pipeline and the second hydrogen pipeline are respectively connected to a second nitrogen pipeline, and the second nitrogen pipeline is used to supply nitrogen to the silicon powder filter, the high-pressure silo and its pipeline through the first hydrogen pipeline and the second hydrogen pipeline respectively to blow out the hydrogen therein.

6. The silicon powder adding system according to claim 1, characterized in that: The silicon powder adding system further comprises a vent filter, which is connected to the tail gas outlet of the low-pressure silo near the top thereof, so that the tail gas in the low-pressure silo enters the vent filter for filtration and then is discharged.

7. The silicon powder adding system according to claim 6, characterized in that: The vent filter is connected to a third nitrogen pipeline, and the third nitrogen pipeline is used to supply nitrogen to the bottom of the vent filter, so that the silicon powder in the vent filter can flow smoothly into the low-pressure silo.

8. The silicon powder adding system according to claim 6, characterized in that: The exhaust gas outlet of the low-pressure silo is connected to the middle and lower part of the vent filter through an exhaust gas pipe; a dust outlet is provided at the top of the silicon powder storage tank, and the dust outlet is connected to the exhaust gas pipe through a dust pipe, so that the dust in the silicon powder storage tank enters the vent filter for filtration.

9. The silicon powder adding system according to claim 1, characterized in that: The discharge port of the silicon powder storage tank and the receiving port of the elevator are connected by a first metal pipe; and / or The discharge port of the elevator and the feed port of the low-pressure silo are connected via a second metal pipe; and / or The discharge port of the low-pressure silo and the feed port of the high-pressure silo are connected via a third metal pipe, and a plurality of shut-off valves are provided on the third metal pipe; the third metal pipe is connected to a fourth nitrogen pipe.

10. The silicon powder adding system according to claim 1, characterized in that: The silicon powder adding system further comprises a silicon powder tanker, which is connected to the silicon powder storage tank and is used to provide silicon powder to the silicon powder storage tank; and / or The silicon powder storage tank is connected to a fifth nitrogen pipeline near its bottom, and the fifth nitrogen pipeline is used to deliver nitrogen into the bottom of the silicon powder storage tank so that the silicon powder in the silicon powder storage tank can flow smoothly into the receiving port of the elevator.

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