A pneumatic conveying and drying system for silicon powder

Abstract

This invention provides a pneumatic conveying and drying system for silicon powder, relating to the field of silicon powder technology. The invention includes a nitrogen storage tank, a pressure regulating device, a heater, a sending tank, a receiving tank, a filter, and a compressor connected in sequence. The compressor is connected to the nitrogen storage tank, the sending tank is connected to a silicon powder silo, and the outlet of the receiving tank faces the hydrogenation furnace. This invention employs closed-loop pneumatic conveying technology, eliminating the need for manual addition of silicon powder, avoiding potential occupational hazards, and simultaneously drying the silicon powder while conveying it.

Description

Technical Field

[0001] This utility model relates to the field of silicon powder technology, specifically to a silicon powder pneumatic conveying and drying system. Background Technology

[0002] Currently, the technology used in my country to produce polysilicon is primarily the modified Siemens process, which accounts for over 80% of the country's total polysilicon production. A crucial step in the modified Siemens process is cold hydrogenation.

[0003] During the cold hydrogenation reaction, silicon powder continuously participates in the reaction to produce trichlorosilane, requiring continuous replenishment of silicon powder to meet the production needs of the entire cold hydrogenation process.

[0004] Currently, ton bags of silicon powder are typically transported to the lifting port using forklifts, and then lifted into a silicon powder collection tank by an overhead crane. After being electrically heated and dried, the powder is added to the system. This method of adding silicon powder requires intermittent manual addition, resulting in high labor costs, potential occupational hazards for workers, direct exposure of the silicon powder to the air, significant dust generation during addition, environmental pollution, and a risk of dust explosion from the fine silicon powder suspended in the air. Utility Model Content

[0005] The purpose of this invention is to develop a pneumatic conveying and drying system for silicon powder that uses closed-loop pneumatic conveying technology, eliminates the need for manual addition of silicon powder, avoids potential occupational hazards to personnel, and simultaneously conveys and dries silicon powder.

[0006] This utility model is achieved through the following technical solution:

[0007] A pneumatic conveying and drying system for silicon powder, comprising:

[0008] The nitrogen storage tank, pressure regulating device, heater, sending tank, receiving tank, filter, and compressor are connected in sequence.

[0009] The compressor is connected to a nitrogen storage tank, the sending tank is connected to a silicon powder silo, and the outlet of the receiving tank faces the hydrogenation furnace.

[0010] Optionally, a first buffer tank is provided on the pipeline between the compressor and the filter, and a second buffer tank is provided on the pipeline between the compressor and the nitrogen storage tank.

[0011] Optionally, the delivery tank is connected to a catalyst tube.

[0012] Optionally, the heater outlet is connected to the top of the sending tank and the pipeline between the sending tank and the receiving tank.

[0013] Optionally, the nitrogen storage tank is connected to an inlet pipe, and the heater is a steam heater.

[0014] Optionally, a dehydration assembly is provided on the pipeline between the nitrogen storage tank and the compressor.

[0015] Optionally, the dehydration assembly includes a first valve located on the pipeline between the compressor and the nitrogen storage tank. Branch pipes are connected to the pipelines on both sides of the first valve, and two adsorption tanks are connected in parallel between the two branch pipes. The adsorption tanks are filled with adsorbent material.

[0016] Optionally, the two adsorption tanks are connected by an inlet pipe and an outlet pipe, which are respectively connected to the two branch pipes. Each of the inlet pipe and the outlet pipe is equipped with two second valves corresponding to the two adsorption tanks.

[0017] Optionally, the inlet pipe is connected to an exhaust pipe, the exhaust pipe is equipped with two third valves, the exhaust pipe between the two third valves is equipped with a muffler that communicates with the outside, the outlet pipe is equipped with a backflush pipe, and the backflush pipe is equipped with a regeneration throttle valve.

[0018] Optionally, an online dew point meter is installed on the pipeline between the compressor and the filter.

[0019] The beneficial effects of this utility model are:

[0020] The silicon powder conveying system employs a closed-loop pneumatic conveying technology, eliminating the need for manual addition of silicon powder and avoiding potential occupational hazards for personnel. The silicon powder is not directly exposed to the air, preventing it from becoming damp and avoiding dust generation, thus mitigating the risk of silicon powder explosion. While using nitrogen to convey the silicon powder, it also dries it; moisture is removed by the dehydration component during nitrogen recovery, achieving nitrogen recycling. Steam is used as the heater heats the nitrogen, saving electricity and reducing production costs. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a structural diagram of Example 1;

[0023] Figure 2 This is a structural diagram of Example 2.

[0024] Reference numerals in the attached diagram: 1. Nitrogen storage tank; 2. Pressure regulating device; 3. Heater; 4. Sending tank; 5. Receiving tank; 6. Filter; 7. First buffer tank; 8. Compressor; 9. Second buffer tank; 10. Silica powder silo; 11. Catalyst tube; 12. First valve; 13. Adsorption tank; 14. Branch pipe; 15. Inlet pipe; 16. Outlet pipe; 17. Exhaust pipe; 18. Silencer; 19. Backflush pipe; 20. Regeneration throttle valve; 21. Online dew point meter. Detailed Implementation

[0025] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0026] In this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0028] Example 1

[0029] like Figure 1 As shown, this embodiment discloses a pneumatic conveying and drying system for silicon powder, including a nitrogen storage tank 1, a pressure regulating device 2, a heater 3, a sending tank 4, a receiving tank 5, a filter 6, a first buffer tank 7, a compressor 8, and a second buffer tank 9 connected in sequence. The second buffer tank 9 is also connected to the nitrogen storage tank 1 via a pipeline.

[0030] Nitrogen storage tank 1 serves as the gas source for pneumatic conveying. The output nitrogen gas is regulated by pressure regulating device 2, heated by heater 3, and then enters sending tank 4. Heater 3 is a steam heater 3, with steam as its heat source. The outlet of heater 3 is connected to the top of sending tank 4 and the pipeline between sending tank 4 and receiving tank 5. Nitrogen storage tank 1 is also equipped with an inlet pipe, which replenishes dry nitrogen gas into nitrogen storage tank 1.

[0031] The sending tank 4 is connected to a silicon powder silo 10 and a catalyst pipe 11. Silicon powder enters the sending tank 4 from the silicon powder silo 10, and the catalyst pipe 11 delivers the catalyst into the sending tank 4.

[0032] Nitrogen gas carries silicon powder mixed with catalyst in sending tank 4 to receiving tank 5. The outlet of receiving tank 5 faces the hydrogenation furnace, and the silicon powder in receiving tank 5 is transported to the hydrogenation furnace.

[0033] Nitrogen gas in receiving tank 5 is delivered to filter 6. After the silicon powder is filtered out by filter 6, the nitrogen gas passes through first buffer tank 7, compressor 8 for pressurization, and second buffer tank 9 in sequence before being returned to nitrogen storage tank 1 to achieve nitrogen reuse.

[0034] Example 2

[0035] like Figure 2 As shown, this embodiment adds a moisture removal device to the nitrogen gas, based on embodiment 1. The moisture removal device filters out the moisture in the nitrogen gas, ensuring that the nitrogen gas entering the nitrogen storage tank 1 is dry.

[0036] The moisture removal device includes an online dew point meter 21 installed on the pipeline between the first buffer tank 7 and the filter 6, and also includes a dehydration component installed on the pipeline between the second buffer tank 9 and the nitrogen storage tank 1.

[0037] The dehydration assembly includes a first valve 12 located on the pipeline between the second buffer tank 9 and the nitrogen storage tank 1. Branch pipes 14 are connected to the pipelines on both sides of the first valve 12. Two adsorption tanks 13 are connected in parallel between the two branch pipes 14. The adsorption tanks 13 are filled with adsorbent material.

[0038] The two adsorption tanks 13 are connected by an inlet pipe 15 and an outlet pipe 16. The inlet pipe 15 and the outlet pipe 16 are respectively connected to two branch pipes 14. The inlet pipe 15 and the outlet pipe 16 are each equipped with two second valves corresponding to the two adsorption tanks 13.

[0039] An exhaust pipe 17 is connected to the inlet pipe 15. Both ends of the exhaust pipe 17 are connected to the inlet pipe 15. Two third valves are provided on the exhaust pipe 17. A muffler 18 connected to the outside is provided on the exhaust pipe 17 between the two third valves.

[0040] The discharge pipe 16 is equipped with a backflush pipe 19, which is connected to the discharge pipe 16 at both ends. The backflush pipe 19 is equipped with a regeneration throttle valve 20.

[0041] During nitrogen recovery, the online dew point meter 21 monitors the moisture content of the nitrogen output from the filter 6. When the moisture content is low, the first valve 12 remains open, and the nitrogen is fed into the nitrogen storage tank 1 through the second buffer tank 9. When the moisture content of the nitrogen output from the filter 6 is high, the online dew point meter 21 needs to remove moisture from the nitrogen. In this case, the first valve 12 is closed, allowing the nitrogen to pass through the adsorption tank 13. After the moisture in the nitrogen is adsorbed by the adsorbent material, the nitrogen is then sent back to the nitrogen storage tank 1.

[0042] The two adsorption tanks 13 work alternately, one for adsorption and dehydration and the other for regeneration. During regeneration, the dry nitrogen gas output from the adsorption tank 13 performing adsorption enters the adsorption tank 13 undergoing regeneration through the backflushing pipe 19. The third valve on the exhaust pipe 17 near the side of the regenerated adsorption tank 13 is opened, so that the dry nitrogen gas backflushes into the regenerated adsorption tank 13 and is discharged through the exhaust pipe 17 and the silencer 18.

[0043] The above embodiments are merely preferred embodiments of this utility model and are not intended to limit the technical solutions of this utility model. Any technical solution that can be implemented based on the above embodiments without creative effort should be considered to fall within the scope of protection of this utility model patent.

Claims

1. A system for pneumatic conveying and drying of silicon powder, characterized in that, include: The nitrogen storage tank, pressure regulating device, heater, sending tank, receiving tank, filter, and compressor are connected in sequence. The compressor is connected to a nitrogen storage tank, the sending tank is connected to a silicon powder silo, and the outlet of the receiving tank faces the hydrogenation furnace. The sending tank is connected to a catalyst tube; A dehydration assembly is provided on the pipeline between the nitrogen storage tank and the compressor. The dehydration assembly includes a first valve on the pipeline between the compressor and the nitrogen storage tank. Branch pipes are connected to the pipelines on both sides of the first valve. Two adsorption tanks are connected in parallel between the two branch pipes. The adsorption tanks are filled with adsorbent material. An online dew point meter is installed on the pipeline between the compressor and the filter.

2. The silicon powder pneumatic conveying and drying system of claim 1, wherein, A first buffer tank is provided on the pipeline between the compressor and the filter, and a second buffer tank is provided on the pipeline between the compressor and the nitrogen storage tank.

3. The silicon powder pneumatic conveying and drying system of claim 1, wherein, The heater outlet is connected to the top of the sending tank and the pipeline between the sending tank and the receiving tank.

4. The silicon powder pneumatic conveying and drying system according to claim 1, characterized in that, The nitrogen storage tank is connected to an air inlet pipe, and the heater is a steam heater.

5. The silicon powder pneumatic conveying and drying system of claim 1, wherein, The two adsorption tanks are connected by an inlet pipe and an outlet pipe, which are respectively connected to the two branch pipes. Each of the inlet pipe and the outlet pipe is equipped with two second valves corresponding to the two adsorption tanks.

6. The silicon powder pneumatic conveying and drying system of claim 5, wherein, The inlet pipe is connected to an exhaust pipe, and the exhaust pipe is equipped with two third valves. A muffler connected to the outside is installed on the exhaust pipe between the two third valves. The outlet pipe is equipped with a backflush pipe, and a regeneration throttle valve is installed on the backflush pipe.

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