Continuous feeding cold hydrogenation fluidization system
By introducing a continuous feeding system and a rotatable defoamer into the cold hydrogenation fluidized bed reactor, the problems of uneven fluidization and unstable bed in the fluidized bed were solved, thereby improving reaction efficiency, reducing costs, and extending the life of the equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XINJIANG GCL NEW ENERGY MATERIALS TECH CO LTD
- Filing Date
- 2025-06-25
- Publication Date
- 2026-04-17
AI Technical Summary
After the cold hydrogenation fluidized bed reactor is enlarged, the fluidization effect deteriorates, and bed fluctuations, channeling and dead bed phenomena occur, resulting in decreased reaction efficiency and increased production costs. At the same time, intermittent silicon powder feeding leads to bed instability and increases maintenance costs.
The continuously fed cold hydrogenation fluidization system maintains good fluidization within the fluidized bed through a motor-driven rotating fluidized bed debubbler and multi-layer multi-swirl guide baffles, and achieves bed stability through a continuous silicon powder feeding unit, avoiding instability caused by intermittent feeding.
It improves the reaction efficiency of fluidized bed reactors, reduces production costs, extends the operating cycle of the unit, reduces maintenance costs, and alleviates the deformation problem of the defoamer.
Smart Images
Figure CN224127235U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of polycrystalline silicon production, specifically relating to a continuous feeding cold hydrogenation fluidization system. Background Technology
[0002] In the hydrogenation process of polysilicon production, the fluidized bed reactor is the core equipment. The process involves heating a mixture of silicon tetrachloride and hydrogen to a certain temperature before it enters the fluidized bed from the bottom. Industrial silicon powder, mixed with a certain proportion of catalyst, reacts under high temperature and high pressure to produce trichlorosilane. A cyclone separator is installed at the fluidized bed outlet to separate the silicon powder and catalyst entrained in the post-reaction gas phase. With the development of cold hydrogenation technology, multi-layer transverse grid debubblers are now commonly used in fluidized bed reactors to improve reaction efficiency and reduce production costs.
[0003] As polysilicon production capacity continues to expand, the design diameter of cold hydrogenation fluidized bed reactors is also increasing. This increased diameter leads to poorer fluidization within the fluidized bed, a more pronounced boundary layer effect, and uneven gas distribution. This results in phenomena such as silicon powder bridging, channeling, and dead beds between adjacent debuffers. This not only severely reduces the effective reaction zone and impacts reaction efficiency, but also, due to the larger inner diameter of the fluidized bed, the diameter of the grid debuffers increases accordingly. Silicon powder accumulation in the debuffers causes deformation of the debuffer guide plates and support ribs. This deformation further exacerbates channeling and dead bed phenomena, ultimately forcing the cold hydrogenation production system to shut down for maintenance. This results in decreased reaction efficiency and increased production costs, while also shortening the unit's operating cycle and increasing maintenance expenses.
[0004] Furthermore, many cold hydrogenation fluidized bed reactors currently use intermittent silicon powder addition. One method involves two approaches: first, after each batch of silicon powder is completely added to the fluidized bed reactor from the high-pressure hopper, the reactor stops adding silicon powder, and the high-pressure hopper needs to be refilled with another batch of silicon powder after 1-2 hours before adding more to the reactor; second, the addition of silicon powder between each batch and the reactor is also intermittent, with the valve from the high-pressure hopper to the reactor opening at specified time intervals to add silicon powder for a predetermined duration. On the one hand, intermittent silicon powder addition to the fluidized bed reactor leads to instability in the bed layer. The bed rises during silicon powder addition and falls when addition stops, resulting in a constant fluctuation in bed temperature. On the other hand, it disrupts the fluidization equilibrium, causing channeling within the bed and creating dead zones. Summary of the Invention
[0005] Purpose of this utility model: The technical problem to be solved by this utility model is to address the shortcomings of existing technologies by providing a novel cold hydrogenation fluidized bed reaction system. This system resolves abnormal phenomena such as bed fluctuations, channeling, and dead beds within the cold hydrogenation fluidized bed reactor, allowing the silicon powder in the channeled areas to be re-fluidized. This not only restores the effective reaction zone within the fluidized bed to its original operating state but also enables the utilization of silicon powder in the channeled and dead bed areas. This results in better fluidization within the fluidized bed, improves the reaction efficiency of the cold hydrogenation reactor, and reduces production costs.
[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:
[0007] A continuously feeding cold hydrogenation fluidized bed system includes a silicon powder continuous feeding unit and a cold hydrogenation fluidized bed. The silicon powder continuous feeding unit is connected to the cold hydrogenation fluidized bed through a feeding pipe, continuously feeding silicon powder into the cold hydrogenation fluidized bed. The cold hydrogenation fluidized bed is equipped with a set of cyclone separators and a set of fluidized bed debubblers. The fluidized bed debubblers are positioned at the same height at the bottom of the cold hydrogenation fluidized bed and are mounted on a central shaft arranged longitudinally within the cold hydrogenation fluidized bed, enabling them to rotate horizontally with the central shaft. A motor for driving the rotation of the central shaft is provided at the top of the cold hydrogenation fluidized bed.
[0008] Furthermore, the fluidized bed breaker is a cylindrical structure with multiple layers of multi-rotation guide baffles inside, and the top multi-rotation guide baffle is flush with the top surface of each fluidized bed breaker; the multi-rotation guide baffle has a circular window reserved on it that corresponds to the air outlet at the top of the fluidized bed breaker.
[0009] Furthermore, a fluidized bed inlet distributor is provided at the bottom of the cold hydrogenated fluidized bed, and the fluidized bed inlet distributor is located below the fluidized bed breaker; a silicon powder feeding port is provided on the bottom side of the cold hydrogenated fluidized bed, and the height of the silicon powder feeding port is located between the fluidized bed inlet distributor and the bottom of the fluidized bed breaker.
[0010] Furthermore, the central shaft is vertically inserted into the cold hydrogenated fluidized bed. The upper end of the central shaft is connected to a motor equipped with a reducer, and a set of fluidized bed debuffers are circumferentially installed at the bottom end of the central shaft. The central shaft is driven to rotate by the motor, thereby causing the fluidized bed debuffers to rotate inside the cold hydrogenated fluidized bed. The insertion port between the central shaft and the cold hydrogenated fluidized bed is mechanically sealed with high-temperature material.
[0011] Furthermore, the bottom of the cold hydrogenation fluidized bed is provided with a feed port for adding silicon tetrachloride and hydrogen, and the synthesis gas separated by the cyclone separator is discharged from the top through a pipe; a pressure gauge for measuring the internal pressure of the cold hydrogenation fluidized bed is also provided on the top side of the cold hydrogenation fluidized bed.
[0012] Specifically, the continuous silicon powder feeding unit includes a low-pressure silicon powder tank and two high-pressure silicon powder tanks; the two high-pressure silicon powder tanks are respectively connected to the discharge pipe of the low-pressure silicon powder tank to receive the silicon powder from the low-pressure silicon powder tank; the two high-pressure silicon powder tanks are respectively connected to the feeding pipe of the cold hydrogenated fluidized bed through the discharge pipe.
[0013] Furthermore, nitrogen purging pipes are connected to the sides of the two silicon powder high-pressure tanks respectively for replenishing nitrogen into the silicon powder high-pressure tanks; and pressure relief pipelines are connected to the tops of the two silicon powder high-pressure tanks respectively for depressurizing the silicon powder high-pressure tanks and sending the depressurized gas to the exhaust gas treatment device.
[0014] Furthermore, valves are respectively installed on the feeding pipes connecting the bottom of the low-pressure silicon powder tank to the high-pressure silicon powder tank; valves are respectively installed on the feeding pipes connecting the bottom of the two high-pressure silicon powder tanks to the cold hydrogenation fluidized bed feeding pipe; and valves are respectively installed on the pressure relief pipelines at the top of the two high-pressure silicon powder tanks.
[0015] Furthermore, the feed pipe of the cold hydrogenated fluidized bed is sequentially equipped with a silicon powder flow limiter and a valve.
[0016] Furthermore, each of the two silicon powder high-pressure tanks is equipped with a pressure gauge for monitoring the internal pressure. Beneficial effects
[0017] (1) In this system, the fluidized bed is equipped with a motor-driven rotatable fluidized bed breaker. At regular intervals or after channeling occurs in the fluidized bed, the breaker is rotated to make the silicon powder bridged between adjacent breakers and the silicon powder accumulated on the breaker in the channeling area re-fluidize, maintaining the original good fluidization form in the fluidized bed, improving the reaction yield and reducing the production cost.
[0018] (2) The fluidized bed reactor in this system is fed with silicon powder continuously without interruption, which stabilizes the bed and avoids bed fluctuations or channeling and dead beds caused by intermittent feeding. It improves the reaction efficiency of the cold hydrogenation reactor and reduces production costs. It extends the system's operating cycle and reduces maintenance costs. It alleviates stress concentration in the grid plate bubble deflator and reduces the possibility of deformation of the bubble deflator internals in the cold hydrogenation fluidized bed. Attached Figure Description
[0019] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.
[0020] Figure 1 This is a schematic diagram of the overall structure of the continuous feeding cold hydrogenation fluidization system of this utility model.
[0021] Figure 2 This is a schematic diagram of the structure of a single-layer multi-swirl guide baffle inside a fluidized bed breaker.
[0022] The reference numerals in the attached figures represent:
[0023] 1-Silicon powder low-pressure tank; 2-Silicon powder high-pressure tank; 3-Silicon powder replenishment flow limiter; 4-Silicon powder feed port; 5-Cold hydrogenated fluidized bed; 6-Fluorescent bed defoamer; 7-Cyclone separator; 8-Fluorescent bed inlet distributor; 9-Central shaft; 10-Motor. Detailed Implementation
[0024] The present invention can be better understood from the following embodiments.
[0025] The structures, proportions, and sizes shown in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art. They are not intended to limit the scope of this invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, provided they do not affect the effectiveness or purpose of this invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, terms such as "upper," "lower," "front," "rear," and "middle" used in this specification are merely for clarity and not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.
[0026] like Figure 1 As shown, the continuous feeding cold hydrogenation fluidized bed system of this utility model includes a silicon powder continuous feeding unit and a cold hydrogenation fluidized bed 5. The silicon powder continuous feeding unit is connected to the cold hydrogenation fluidized bed 5 through a feeding pipe and continuously feeds silicon powder into the cold hydrogenation fluidized bed 5. The cold hydrogenation fluidized bed 5 is equipped with a set of cyclone separators 7 and a set of fluidized bed debubblers 6. The fluidized bed debubblers 6 are arranged at the same height at the lower part of the cold hydrogenation fluidized bed 5 and are installed on a central shaft 9 arranged longitudinally in the cold hydrogenation fluidized bed 5, and can rotate horizontally with the central shaft 9. A motor 10 for driving the rotation of the central shaft 9 is provided at the top of the cold hydrogenation fluidized bed 5.
[0027] like Figure 2 As shown, the fluidized bed breaker 6 is a cylindrical structure with multiple layers of multi-rotation guide baffles inside. The top multi-rotation guide baffle is flush with the top surface of each fluidized bed breaker 6. The multi-rotation guide baffle has a circular window corresponding to the air outlet at the top of the fluidized bed breaker 6.
[0028] A fluidized bed inlet distributor 8 is provided at the bottom of the cold hydrogenated fluidized bed 5, and the fluidized bed inlet distributor 8 is located below the fluidized bed breaker 6; a silicon powder feed port 4 is provided on the bottom side of the cold hydrogenated fluidized bed 5, and the height of the silicon powder feed port 4 is between the fluidized bed inlet distributor 8 and the bottom of the fluidized bed breaker 6.
[0029] The central shaft 9 is vertically inserted into the cold hydrogenated fluidized bed 5. The upper end of the central shaft 9 is driven and connected to the motor 10 equipped with a reducer. A set of fluidized bed debubblers 6 are circumferentially installed at the bottom end of the central shaft 9. The central shaft 9 is driven to rotate by the motor 10, thereby driving the fluidized bed debubblers 6 to rotate inside the cold hydrogenated fluidized bed 5. The insertion port between the central shaft 9 and the cold hydrogenated fluidized bed 5 is mechanically sealed with high-temperature material.
[0030] The bottom of the cold hydrogenation fluidized bed 5 is equipped with a feed port for adding silicon tetrachloride and hydrogen, and the synthesis gas separated by the cyclone separator 7 is discharged from the top through a pipe; a pressure gauge P2 for measuring the internal pressure of the cold hydrogenation fluidized bed 5 is also provided on the top side of the cold hydrogenation fluidized bed 5.
[0031] The mixed feed gas of silicon tetrachloride and hydrogen enters the fluidized bed from the bottom of the cold hydrogenated fluidized bed 5, and enters the zoned fluidized bed through the fluidized bed inlet distributor 8 to react with silicon powder. The gas-solid mixture after the reaction enters the built-in cyclone separator 7 from the top of the zoned fluidized bed breaker 6. After dust removal, the solid particles return to the fluidized bed from the bottom of the built-in cyclone separator 7, and the gas enters the downstream from the top of the fluidized bed reactor.
[0032] The continuous silicon powder feeding unit includes a low-pressure silicon powder tank 1 and two high-pressure silicon powder tanks 2, one for use and one for standby; the two high-pressure silicon powder tanks 2 are respectively connected to the discharge pipe of the low-pressure silicon powder tank 1 to receive the silicon powder from the low-pressure silicon powder tank 1; the two high-pressure silicon powder tanks 2 are respectively connected to the feeding pipe of the cold hydrogenated fluidized bed 5 through the discharge pipe.
[0033] The sides of the two silicon powder high-pressure tanks 2 are respectively connected to nitrogen purging pipes for replenishing nitrogen into the silicon powder high-pressure tanks 2; the tops of the two silicon powder high-pressure tanks 2 are respectively connected to pressure relief pipelines for depressurizing the silicon powder high-pressure tanks 2 and sending the depressurized gas to the tail gas treatment device.
[0034] When silicon powder high-pressure tank A is replenished with silicon powder normally, silicon powder high-pressure tank B is filled with silicon powder and pressurized with hydrogen to the pressure required for the silicon powder feeding process. After silicon powder in high-pressure tank A is replenished, its silicon powder replenishment valve is closed, and the silicon powder replenishment valve in high-pressure tank B is opened to achieve continuous fluidized bed feeding. Silicon powder high-pressure tank A is depressurized, and silicon powder is replenished from the low-pressure silicon powder tank. Then, high-pressure tank A is pressurized with hydrogen for standby. Similarly, after silicon powder in high-pressure tank B is replenished, its silicon powder replenishment valve is closed, and the silicon powder replenishment valve in high-pressure tank A is opened. Silicon powder in high-pressure tank B is depressurized, and silicon powder is replenished from the low-pressure silicon powder tank. Then, high-pressure tank B is pressurized with hydrogen for standby. One low-pressure silicon powder tank is set up, and silicon powder is directly transported into the low-pressure silicon powder tank by a silicon powder tank truck. After the low-pressure silicon powder tank is full, silicon powder is replenished to high-pressure tanks A and B alternately. After the silicon powder in the low-pressure silicon powder tank is replenished to the high-pressure silicon powder tank, it is directly transported to the low-pressure silicon powder tank by the silicon powder tank truck.
[0035] In some embodiments, valves are respectively installed on the feeding pipes connecting the bottom of the low-pressure silicon powder tank 1 to the high-pressure silicon powder tank 2; valves are respectively installed on the feeding pipes connecting the bottom of the two high-pressure silicon powder tanks 2 to the feeding pipes of the cold hydrogenated fluidized bed 5; and valves are respectively installed on the pressure relief pipelines at the top of the two high-pressure silicon powder tanks 2.
[0036] In some embodiments, a silicon powder replenishment flow limiter 3 and a valve are sequentially installed on the feed pipe of the cold hydrogenated fluidized bed 5. The flow limiter is installed on the feed pipe from the silicon powder high-pressure tank to the cold hydrogenated fluidized bed to prevent a large amount of silicon powder from entering the fluidized bed reactor at once, causing fluctuations in the fluidized bed layer or temperature. After installing the flow limiter, the silicon powder replenishment amount is controlled by controlling the pressure difference between the silicon powder high-pressure tank and the fluidized bed. Based on the required bed pressure difference according to process requirements, the bed pressure difference is controlled in cascade with the pressure difference between the silicon powder high-pressure tank and the fluidized bed, and the hydrogen pressurization regulating valve of the silicon powder high-pressure tank. This achieves automatic control of the pressure difference between the silicon powder high-pressure tank and the fluidized bed through the hydrogen pressurization regulating valve of the silicon powder high-pressure tank according to process requirements, thereby controlling the silicon powder replenishment amount and achieving fluidized bed stability.
[0037] In some embodiments, pressure gauges P1a and P1b are respectively installed on the two silicon powder high-pressure tanks 2 for monitoring internal pressure, and pressure gauge P2 is installed on the top of the fluidized bed. The pressure difference PDIa between the silicon powder high-pressure tank A and the fluidized bed reactor is calculated by the displayed values of P1a and P2, and the pressure difference PDIb between the silicon powder high-pressure tank A and the fluidized bed reactor is calculated by the displayed values of P1b and P2. The amount of silicon powder replenishment is controlled by the values of PDIa and PDIb.
[0038] When in use, after the fluidized bed has been running for 2 months, start the motor regularly every month to drive the multi-layer fluidized bed debuffer to rotate slowly in both directions for 2-3 revolutions. This will cause the silicon powder in the dead zone above the debuffer in the fluidized bed to be fluidized again. In this way, not only will the effective reaction zone inside the fluidized bed be restored to its original operating state, but the silicon powder in the dead zone of the fluidized bed can also be utilized.
[0039] When the fluidized bed experiences large deviations in the temperature measurement points, large fluctuations in the bed layer, and obvious channeling during operation, start the motor to drive the multi-layered bubble breakers to slowly rotate forward and backward for 2-3 revolutions. This will cause the silicon powder in the dead zone above the bubble breakers to be re-fluidized, restoring the effective reaction zone inside the fluidized bed to its original operating state.
[0040] This system solves the problems of channeling and dead bed in cold hydrogenation fluidized bed reactors, maintains good dispersed fluidization within the fluidized bed, improves the reaction efficiency of cold hydrogenation reactors, and reduces production costs. It extends the system's operating cycle and reduces maintenance costs. It alleviates stress concentration in the grid plate bubble deflator, reducing the possibility of deformation of the bubble deflator internals in the cold hydrogenation fluidized bed. It enables automatic replenishment of silicon powder according to the required bed height, reducing wear on the silicon powder replenishment valve from the high-pressure silicon powder tank to the fluidized bed reactor, and saving on valve replacement and maintenance costs.
[0041] This invention provides a concept and method for a continuously fed cold hydrogenation fluidization system. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technology.
Claims
1. A continuously fed, cold hydrogenation fluidization system characterized by, The system includes a continuous silicon powder feeding unit and a cold hydrogenated fluidized bed (5). The continuous silicon powder feeding unit is connected to the cold hydrogenated fluidized bed (5) through a feeding pipe and continuously feeds silicon powder into the cold hydrogenated fluidized bed (5). The cold hydrogenated fluidized bed (5) is equipped with a set of cyclone separators (7) and a set of fluidized bed debubblers (6). The fluidized bed debubblers (6) are arranged at the same height at the bottom of the cold hydrogenated fluidized bed (5) and are installed on the central shaft (9) arranged longitudinally in the cold hydrogenated fluidized bed (5), and can rotate horizontally with the central shaft (9). The top of the cold hydrogenated fluidized bed (5) is equipped with a motor (10) for driving the central shaft (9) to rotate.
2. The continuously fed cold hydrogenation fluidization system of claim 1, wherein, The fluidized bed breaker (6) is a cylindrical structure with multiple layers of multi-rotation guide baffles inside. The top multi-rotation guide baffle is flush with the top surface of each fluidized bed breaker (6). The multi-rotation guide baffle has a circular window corresponding to the air outlet at the top of the fluidized bed breaker (6).
3. The continuously fed cold hydrogenation fluidization system of claim 1, wherein, The cold hydrogenated fluidized bed (5) is provided with a fluidized bed inlet distributor (8) at the bottom, which is located below the fluidized bed breaker (6); the bottom side of the cold hydrogenated fluidized bed (5) is provided with a silicon powder feed port (4), which is located between the bottom of the fluidized bed inlet distributor (8) and the bottom of the fluidized bed breaker (6).
4. The continuously fed cold hydrogenation fluidization system of claim 1, wherein, The central shaft (9) is vertically inserted into the cold hydrogenated fluidized bed (5). The upper end of the central shaft (9) is driven and connected to a motor (10) equipped with a reducer. A set of fluidized bed debubblers (6) is installed circumferentially at the bottom end of the central shaft (9). The central shaft (9) is driven to rotate by the motor (10), thereby driving the fluidized bed debubblers (6) to rotate inside the cold hydrogenated fluidized bed (5). The insertion port between the central shaft (9) and the cold hydrogenated fluidized bed (5) is mechanically sealed with high-temperature material.
5. The continuously fed cold hydrogenation fluidization system of claim 1, wherein, The bottom of the cold hydrogenation fluidized bed (5) is provided with a feed port for adding silicon tetrachloride and hydrogen, and the synthesis gas separated by the cyclone separator (7) is discharged from the top through a pipe; a pressure gauge for measuring the internal pressure of the cold hydrogenation fluidized bed (5) is also provided on the top side of the cold hydrogenation fluidized bed (5).
6. The continuously fed cold hydrogenation fluidization system of claim 1, wherein, The continuous silicon powder feeding unit includes a silicon powder low-pressure tank (1) and two silicon powder high-pressure tanks (2); the two silicon powder high-pressure tanks (2) are respectively connected to the discharge pipe of the silicon powder low-pressure tank (1) to receive the silicon powder from the silicon powder low-pressure tank (1); the two silicon powder high-pressure tanks (2) are respectively connected to the feeding pipe of the cold hydrogenated fluidized bed (5) through the discharge pipe.
7. The continuously fed cold hydrogenation fluidization system of claim 6, wherein, The two silicon powder high-pressure tanks (2) are respectively connected to nitrogen purging pipes on their sides for replenishing nitrogen into the silicon powder high-pressure tanks (2); the tops of the two silicon powder high-pressure tanks (2) are respectively connected to pressure relief pipelines for depressurizing the silicon powder high-pressure tanks (2) and sending the depressurized gas to the tail gas treatment device.
8. The continuously fed cold hydrogenation fluidization system of claim 7, wherein, Valves are installed on the feed pipes connecting the bottom of the low-pressure silicon powder tank (1) to the high-pressure silicon powder tank (2); valves are installed on the feed pipes connecting the bottom of the two high-pressure silicon powder tanks (2) to the feed pipes of the cold hydrogenated fluidized bed (5); valves are installed on the pressure relief pipelines at the top of the two high-pressure silicon powder tanks (2).
9. The continuously fed cold hydrogenation fluidization system of claim 6, wherein, The feed pipe of the cold hydrogenated fluidized bed (5) is equipped with a supplementary silicon powder flow limiter (3) and a valve in sequence.
10. The continuously fed cold hydrogenation fluidization system of claim 6, wherein, The two silicon powder high-pressure tanks (2) are each equipped with a pressure gauge for monitoring the internal pressure.