Polysilicon hydrogenation device silicon powder efficient recovery system
By using a three-stage gradient separation system and a dust removal combination technology, the problems of low silicon powder separation efficiency and clogging were solved, enabling efficient recovery and recycling of silicon powder, and reducing production costs and equipment maintenance requirements.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 内蒙古鑫元硅材料科技有限公司
- Filing Date
- 2025-07-10
- Publication Date
- 2026-06-26
AI Technical Summary
In existing technologies, single-stage cyclone separators have insufficient separation efficiency for silicon powder, causing micron-sized silicon powder to escape into the downstream system, increasing the risk of equipment wear and blockage. Furthermore, the filters are prone to clogging, requiring frequent filter replacements, which increases maintenance costs and downtime.
A three-stage gradient separation system is adopted, including an internal cyclone separator, a dual cyclone separator, and a metal filter, combined with a return chute and a silicon powder collection tank, to achieve efficient recovery of silicon powder. Sticky silicon powder is removed by a combination of hydrogen purging, pulse backflushing, and sonic cleaning to ensure continuous operation of the system.
It significantly improves silicon powder recovery efficiency, reduces equipment wear and blockage risks, extends equipment maintenance cycles, reduces silicon powder waste and production costs, and ensures the continuous and efficient operation of the system.
Smart Images
Figure CN224404738U_ABST
Abstract
Description
Technical fields:
[0002] This utility model relates to the field of polycrystalline silicon hydrogenation, specifically to a high-efficiency silicon powder recovery system for polycrystalline silicon hydrogenation devices. Background technology:
[0004] In the production of polysilicon, the hydrogenation process is a critical step.
[0005] During the hydrogenation reaction, silicon tetrachloride and hydrogen are mixed and heated before being introduced into a fluidized bed reactor to react with added silicon powder to produce trichlorosilane. In this process, unreacted silicon powder may enter the downstream system with the reaction gas. To prevent clogging of the downstream system due to silicon powder entering, a single-stage cyclone separator is often used at the outlet of the fluidized bed reactor to treat the reaction gas. However, in actual operation, the separation efficiency of the single-stage cyclone separator for silicon powder is insufficient, often only around 85%, resulting in the escape of micron-sized silicon powder. This still fails to solve the problems of silicon powder mixing with chlorosilanes in the downstream system, increasing wear on downstream equipment, and reducing the risk of equipment and pipeline blockage. Even with the addition of a filter after the cyclone separator, the small particle size and high viscosity of silicon powder easily clog the filter element, causing a sharp increase in operating pressure drop. This not only affects the normal operation of the system but also requires frequent filter element replacement, increasing maintenance costs and equipment downtime. Utility model content:
[0007] In order to solve the above problems, the purpose of this utility model is to provide a high-efficiency silicon powder recovery system for polycrystalline silicon hydrogenation device.
[0008] This utility model is implemented by the following technical solution:
[0009] A high-efficiency silicon powder recovery system for a polycrystalline silicon hydrogenation device includes a fluidized bed reactor, an internal cyclone separator, a dual cyclone separator, a metal filter, and a silicon powder collection tank.
[0010] Multiple internal cyclone separators are fixedly installed at the top inside the fluidized bed reactor by a fixed bracket. The multiple internal cyclone separators are evenly arranged on the circumference with the center located on the central axis of the fluidized bed reactor. The air outlets of the multiple internal cyclone separators are all connected to the air inlet of the gas collecting pipe, and the air outlet of the gas collecting pipe is connected to the reaction gas outlet at the top of the fluidized bed reactor.
[0011] The reaction gas outlet of the fluidized bed reactor is connected to the air inlet of the dual cyclone separator via a pipeline, and the air outlet of the dual cyclone separator is connected to the air inlet of the metal filter via a pipeline.
[0012] The discharge port of the dual cyclone separator is divided into two paths. One path is connected to the inlet end of the return chute, and the outlet end of the return chute penetrates the side wall of the fluidized bed reactor and extends to the dense phase zone at the bottom of the fluidized bed reactor. The other path is connected to the discharge port of the metal filter and the inlet of the silicon powder collection tank through the discharge chute.
[0013] A return valve is provided on the return chute, and a discharge valve is provided on the discharge chute.
[0014] Furthermore, the number of silicon powder collection tanks is at least two, and the discharge chutes at the outlet of the dual cyclone separator and the outlet of the metal filter are divided into two paths, which are respectively connected to the inlets of the two silicon powder collection tanks through collection chutes, and a collection valve is provided on each collection chute.
[0015] Furthermore, each of the silicon powder collection tanks is equipped with a pressure sensor, and a pressure relief port is provided at the top of the silicon powder collection tank. The pressure relief port is connected to the air inlet of the bag filter through a pressure relief pipeline. The air outlet of the bag filter is connected to the venting pipeline, and the discharge port of the bag filter is connected to the inlet of the collection trough. A pressure relief valve is provided on the pressure relief pipeline.
[0016] Furthermore, a sampling port is provided on the air outlet pipe of the metal filter, and a sampling tube is connected to the sampling port.
[0017] Furthermore, it also includes a compressed hydrogen source, the outlet of which is connected to the outlet of the metal filter via a pipeline, and a pulse valve is provided at the outlet of the compressed hydrogen source.
[0018] Furthermore, it also includes an acoustic cleaner located on top of the metal filter.
[0019] Furthermore, it also includes a purge hydrogen source, the outlet of which is connected to the inlet of the purge hydrogen pipeline, and the outlet of the purge hydrogen pipeline extends through the side wall of the fluidized bed reactor into the fluidized bed reactor; at least one purge port is provided on the discharge leg at the bottom of each internal cyclone separator, and each purge port is connected to the outlet of the purge hydrogen pipeline through a pipeline; a purge valve is provided at the outlet of the purge hydrogen source.
[0020] Advantages of this utility model:
[0021] 1. This utility model improves the silicon powder recovery efficiency by using a three-stage gradient separation: internal cyclone separator + dual cyclone separator + metal filter, which solves the problem of low separation efficiency of traditional single-stage cyclone separators and significantly reduces the risk of wear and blockage of downstream system equipment.
[0022] 2. The silicon powder separated by the dual cyclone separator can be returned to the dense phase zone of the fluidized bed reactor via a return chute, realizing raw material recycling and reducing silicon powder waste. Meanwhile, the silicon powder collected in the silicon powder collection tank can be reused as raw material or sold externally, further reducing production costs.
[0023] 3. By combining hydrogen purging of the material legs of the internal cyclone separator, pulse backflushing of the metal filter, and sonic cleaning, the problem of high viscosity and easy clogging of silicon powder is effectively solved. Compared with the frequent replacement of filter elements in traditional filters, this system significantly extends the equipment maintenance cycle and reduces downtime and maintenance costs.
[0024] 4. The rotation and external discharge of multiple silicon powder collection tanks ensure the continuity of the silicon powder collection process and do not affect the operation of the main system.
[0025] 5. Precise control of each stage is achieved through return valve, discharge valve, and collection valve. Based on sampling and testing, it can be determined whether the recovered silicon powder can be used, thereby improving the silicon powder recycling rate while ensuring reaction efficiency. Attached image description:
[0027] Figure 1 This is a schematic diagram of the system connection in this embodiment;
[0028] In the diagram: 1. Fluidized bed reactor; 2. Internal cyclone separator; 3. Double cyclone separator; 4. Metal filter; 5. Silica powder collection tank; 6. Gas collection pipe; 7. Return chute; 8. Discharge chute; 9. Return valve; 10. Discharge valve; 11. Collection chute; 12. Collection valve; 13. Pressure sensor; 14. Pressure relief pipeline; 15. Bag filter; 16. Collection trough; 17. Pressure relief valve; 18. Sampling pipe; 19. Compressed hydrogen source; 20. Pulse valve; 21. Acoustic cleaner; 22. Purging hydrogen source; 23. Purging hydrogen pipeline; 24. Purging valve. Detailed implementation method:
[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0031] Example 1:
[0032] like Figure 1 The polycrystalline silicon hydrogenation device shown includes a high-efficiency silicon powder recovery system, comprising a fluidized bed reactor 1, an internal cyclone separator 2, a dual cyclone separator 3, a metal filter 4, and a silicon powder collection tank 5.
[0033] Four internal cyclone separators 2 are fixedly installed at the top inside the fluidized bed reactor 1 by a fixed bracket. The four internal cyclone separators 2 are evenly arranged on the circumference with the center located on the central axis of the fluidized bed reactor 1. The air outlets of the four internal cyclone separators 2 are all connected to the air inlet of the gas collecting pipe 6, and the air outlet of the gas collecting pipe 6 is connected to the reaction gas outlet at the top of the fluidized bed reactor 1.
[0034] The reaction gas outlet of the fluidized bed reactor 1 is connected to the air inlet of the double cyclone separator 3 through a pipe. The air outlet of the double cyclone separator 3 is connected to the air inlet of the metal filter 4 through a pipe. The air outlet of the metal filter 4 enters the subsequent system. A sampling port is provided on the air outlet pipe of the metal filter 4, and a sampling tube 18 is connected to the sampling port.
[0035] The discharge port of the double cyclone separator 3 is divided into two paths. One path is connected to the feed end of the return chute 7. The discharge end of the return chute 7 penetrates the side wall of the fluidized bed reactor 1 and extends to the dense phase zone at the bottom of the fluidized bed reactor 1. The other path is connected to the discharge port of the metal filter 4 through the discharge chute 8 and the feed port of the silicon powder collection tank 5.
[0036] A return valve 9 is provided on the return chute 7, and a discharge valve 10 is provided on the discharge chute 8.
[0037] In this embodiment, there are three silicon powder collection tanks 5. The discharge chutes 8 at the outlets of the double cyclone separator 3 and the metal filter 4 are divided into two paths, which are connected to the inlets of two of the silicon powder collection tanks 5 through collection chutes 11. Each collection chute 11 is equipped with a collection valve 12. A pressure sensor 13 is installed inside each silicon powder collection tank 5. A pressure relief port is opened at the top of the silicon powder collection tank 5. The pressure relief port is connected to the air inlet of the bag filter 15 through a pressure relief pipeline 14. The air outlet of the bag filter 15 is connected to the venting pipeline. The discharge port of the bag filter 15 is connected to the inlet of the collection trough 16. A pressure relief valve 17 is installed on the pressure relief pipeline 14.
[0038] This embodiment also includes a compressed hydrogen source 19, the outlet of which is connected to the outlet of the metal filter 4 via a pipeline, and a pulse valve 20 is provided at the outlet of the compressed hydrogen source 19.
[0039] It also includes an acoustic cleaner 21, which is located on top of the metal filter 4.
[0040] It also includes a purging hydrogen source 22, the outlet of which is connected to the inlet of the purging hydrogen pipeline 23, and the outlet of the purging hydrogen pipeline 23 extends through the side wall of the fluidized bed reactor 1 into the fluidized bed reactor 1; three purging ports are provided on the discharge leg at the bottom of each internal cyclone separator 2, and the purging ports are all connected to the outlet of the purging hydrogen pipeline 23 through pipelines; a purging valve 24 is provided at the outlet of the purging hydrogen source 22.
[0041] Job Description:
[0042] During the hydrogenation reaction, unreacted silicon powder flows upward with the reaction gas and first enters the four internal cyclone separators 2 at the top of the fluidized bed reactor 1. Centrifugal force is used to initially separate silicon powder with a particle size >50μm. The separated silicon powder falls through the bottom feed leg, while the reaction gas containing a small amount of fine silicon powder flows through the outlet of the internal cyclone separator 2 into the gas collecting pipe 6 and exits from the reaction gas outlet at the top of the reactor. The gas exiting the reaction gas outlet then enters the double cyclone separator 3 for secondary deep separation, separating silicon powder with a particle size >5μm. The separated silicon powder is divided into two paths through the discharge port: one path returns to the bottom dense phase zone of the fluidized bed reactor 1 through the return chute 7 to participate in the reaction again; the other path enters the silicon powder collection tank 5 through the discharge chute 8. The gas processed by the double cyclone separator 3 enters the metal filter 4, where the remaining trace amounts of silicon powder with a particle size <5μm are intercepted by the metal filter element. The purified gas is discharged from the outlet. By setting up three silicon powder collection tanks 5, with the dual cyclone separator 3 and metal filter 4 connected to two of them, dual-tank recycling can be achieved. While ensuring continuous silicon powder feeding, the opening and closing of the collection valve 12 facilitates the individual purification and reuse of silicon powder in each collection tank 5. Simultaneously, the pressure sensor 13 monitors the pressure inside the silicon powder collection tank 5 in real time. In case of overpressure, the pressure relief valve 17 on the pressure relief pipeline 14 can be opened to send the dust-laden gas into the bag filter 15 for purification. The separated silicon powder falls into the collection trough 16, and the purified gas is discharged through the vent pipeline.
[0043] In this embodiment, to prevent blockage of the material legs in the inner cyclone separator 2, hydrogen is continuously supplied by the purging hydrogen source 22 and sent to the three purging ports of each material leg through the purging hydrogen pipeline 23. The airflow disturbance prevents silicon powder deposition, causing the silicon powder to fall through the bottom material leg. Part of it re-participates in the reaction, and part of it re-enters the inner cyclone separator 2 with the reaction gas for separation.
[0044] To ensure filtration efficiency, the system periodically provides reverse high-pressure airflow through compressed hydrogen source 19 and pulse valve 20, which, in conjunction with the top acoustic cleaner 21, removes silicon powder adhering to the surface of the metal filter element 4. Simultaneously, the trichlorosilane content in the gas can be periodically detected by sampling tube 18 from the outlet duct, or by component analysis at the product end. When the detected trichlorosilane content is lower than a preset low value, it indicates low reaction efficiency, and the return valve 9 can be closed to stop the return process, preventing unreacted impurities from accumulating in the fluidized bed and further reducing the conversion rate. When the detected trichlorosilane content is higher than a preset high value, it indicates high reaction efficiency, and the return valve 9 can be opened to reuse the recovered silicon powder, thereby increasing the silicon powder reuse rate and reducing production costs.
[0045] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A polysilicon hydrogenation device silicon powder high-efficiency recovery system comprising a fluidized bed reactor, characterized in that, It also includes an internal cyclone separator, a dual cyclone separator, a metal filter, and a silicon powder collection tank; Multiple internal cyclone separators are fixedly installed at the top inside the fluidized bed reactor by a fixed bracket. The multiple internal cyclone separators are evenly arranged on the circumference with the center located on the central axis of the fluidized bed reactor. The air outlets of the multiple internal cyclone separators are all connected to the air inlet of the gas collecting pipe, and the air outlet of the gas collecting pipe is connected to the reaction gas outlet at the top of the fluidized bed reactor. The reaction gas outlet of the fluidized bed reactor is connected to the air inlet of the dual cyclone separator via a pipeline, and the air outlet of the dual cyclone separator is connected to the air inlet of the metal filter via a pipeline. The discharge port of the dual cyclone separator is divided into two paths. One path is connected to the inlet end of the return chute, and the outlet end of the return chute penetrates the side wall of the fluidized bed reactor and extends to the dense phase zone at the bottom of the fluidized bed reactor. The other path is connected to the discharge port of the metal filter and the inlet of the silicon powder collection tank through the discharge chute. A return valve is provided on the return chute, and a discharge valve is provided on the discharge chute.
2. The system of claim 1, wherein the system further comprises a high-efficiency silicon powder recovery system. The number of silicon powder collection tanks is at least two, and the discharge chutes at the outlet of the dual cyclone separator and the outlet of the metal filter are divided into two paths, which are respectively connected to the inlets of the two silicon powder collection tanks through the collection chutes, and a collection valve is provided on each collection chute.
3. The system of claim 2, wherein the system further comprises a high-efficiency silicon powder recovery system. Pressure sensors are installed in each of the silicon powder collection tanks. A pressure relief port is opened at the top of the silicon powder collection tank. The pressure relief port is connected to the air inlet of the bag filter through a pressure relief pipeline. The air outlet of the bag filter is connected to the venting pipeline. The material outlet of the bag filter is connected to the material inlet of the collection trough. A pressure relief valve is installed on the pressure relief pipeline.
4. The system of claim 1, wherein the system further comprises a high-efficiency silicon powder recovery system. A sampling port is provided on the air outlet pipe of the metal filter, and a sampling tube is connected to the sampling port.
5. The system of claim 1, wherein the system further comprises a high-efficiency silicon powder recovery system. It also includes a compressed hydrogen source, the outlet of which is connected to the outlet of the metal filter via a pipeline, and a pulse valve is provided at the outlet of the compressed hydrogen source.
6. The system of claim 1, wherein the system further comprises a high-efficiency silicon powder recovery system. It also includes an acoustic cleaner, which is located on top of the metal filter.
7. The high-efficiency silicon powder recovery system for a polycrystalline silicon hydrogenation device according to claim 1, characterized in that, It also includes a purge hydrogen source, the outlet of which is connected to the inlet of the purge hydrogen pipeline, and the outlet of the purge hydrogen pipeline extends through the side wall of the fluidized bed reactor into the fluidized bed reactor; at least one purge port is provided on the discharge leg at the bottom of each internal cyclone separator, and each purge port is connected to the outlet of the purge hydrogen pipeline through a pipeline; a purge valve is provided at the outlet of the purge hydrogen source.