Fluidized bed equipment for preparing granular silicon by silane method

Abstract

The utility model relates to the field of polycrystalline silicon production equipment, in particular to fluidized bed equipment for preparing granular silicon by a silane method. The fluidized bed equipment for preparing the granular silicon by the silane method comprises a reaction chamber and a stirring device, the stirring device is arranged on the bottom side of the reaction chamber and is used for stirring materials in the reaction chamber. By introducing the stirring device at the bottom of the reaction chamber, the mixing between reaction gas and solid silicon particles is enhanced, the mixing and heat transfer efficiency of the silicon particles is improved, and particle aggregation and local overheating are prevented, so that the reaction rate and the product uniformity are improved. The generation of silicon powder and hydrogen is effectively reduced, and the conversion rate of silane-particle silicon is improved.

Description

Technical Field

[0001] The present application relates to the field of polysilicon production equipment, and particularly to a fluidized bed device for preparing granular silicon by the silane method. Background Art

[0002] With the continuous growth of the global demand for renewable energy, solar energy, as a clean and sustainable form of energy, has received extensive attention. As a key component for solar energy conversion, the quality and production cost of polysilicon, the main raw material of solar cells, directly affect the performance and price of solar cells.

[0003] In recent years, granular silicon technology has been emphasized due to its advantages such as low cost and low energy consumption. Granular silicon is produced by the silane fluidized bed method, which uses the thermal decomposition of high-purity silane to carry out chemical vapor deposition in a fluidized bed to produce granular polysilicon. The granular silicon technology can not only achieve lower production costs, but also has lower energy consumption and environmental impact, meeting the current requirements for green production and sustainable development.

[0004] Currently, there are some limitations in the preparation methods of granular silicon. For example, the invention patent with the publication number CN118267937A specifically discloses a reactor for producing granular silicon. An auxiliary gas inlet is arranged on the periphery of the bottom of the reactor main body, and the raw material gas inlet and the granular silicon outlet are arranged within the ring formed by the auxiliary gas inlet. Thus, when the auxiliary gas enters the reactor main body through the auxiliary gas inlet, an annular gas curtain is formed in the reactor main body, which can effectively play the role of gas curtain isolation. The raw material gas and the seed crystal (i.e., silicon seed crystal) react in the middle area surrounded by the gas curtain. In addition, a first heating element is used for preheating the seed crystal, and a second heating element is used for heating the raw material gas and the granular silicon, so that the temperature in the core reaction area of the inner wall of the reactor main body is maintained within the normal control range.

[0005] However, the limitations of the above equipment are that when the silicon seed crystal or granular silicon precipitates at the bottom of the reactor, on the one hand, under the heating of the heating element, the silicon seed crystal and granular silicon are likely to overheat, which is not conducive to the continuous deposition and forming of granular silicon; on the other hand, the raw material gas is not easily mixed and reacted with the silicon seed crystal or granular silicon, affecting the deposition efficiency of granular silicon. Utility Model Content

[0006] In order to ensure the deposition efficiency of granular silicon and achieve continuous production, the present application provides a fluidized bed device for preparing granular silicon by the silane method.

[0007] The fluidized bed device for preparing granular silicon by the silane method provided by the present application adopts the following technical solutions:

[0008] A fluidized bed device for preparing granular silicon by the silane method, comprising a reaction chamber and a stirring device; the stirring device is arranged at the bottom side of the reaction chamber and is used for stirring the materials inside the reaction chamber.

[0009] By adopting the above technical solution, the introduction of the stirring device at the bottom of the reaction chamber enhances the mixing between the reaction gas and the solid silicon particles, improves the mixing and heat transfer efficiency of the silicon particles, prevents particle aggregation and local overheating, thereby increasing the reaction rate and product uniformity. It effectively reduces the generation of silicon powder and hydrogen, and improves the conversion rate of silane to granular silicon; at the same time, the stirring device can better maintain the fluidized state of the silicon particles in the heating section.

[0010] Preferably, the stirring device is detachably connected to the side wall of the reaction chamber; the stirring device includes a rotatably arranged stirring blade, and an isolation coating is provided on the surface of the stirring blade.

[0011] By adopting the above technical solution, this design makes the stirring device easy to install and maintain. At the same time, the isolation coating can prevent the stirring blade from sticking to the reaction materials, ensuring the stirring effect.

[0012] Preferably, the reaction chamber includes an inner cylinder and an outer cylinder. The inner cylinder includes a plurality of cylinder segments, and the plurality of cylinder segments are spliced; a heat insulation layer is provided on the outer cylinder.

[0013] By adopting the above technical solution, the segmented design of the inner cylinder facilitates flexible adjustment of the height of the reaction chamber according to production requirements, while the heat insulation layer on the outer cylinder can reduce heat loss, improve energy utilization efficiency, and further reduce production costs.

[0014] Preferably, it further includes a heating device, which is arranged on the outer wall of the inner cylinder and is used for heating the inside of the inner cylinder.

[0015] By adopting the above technical solution, the setting of the heating device can provide the heat required for the reaction, ensure that the reaction proceeds under suitable temperature conditions, and thus is beneficial to improving the quality and output of granular silicon.

[0016] Preferably, the heating device includes a resistance heater and a microwave heater.

[0017] By adopting the above technical solution, the combination of resistance heating and microwave heating can provide a more uniform heat distribution. The main heat directly acts on the silicon seed crystal, reducing side reactions caused by local overheating. This combined heating method can not only achieve rapid heating but also ensure heating uniformity, thereby further improving the preparation effect of granular silicon.

[0018] Preferably, two groups of resistance heaters are provided and distributed along the length direction of the inner cylinder, and the microwave heater is arranged between the two groups of resistance heaters.

[0019] By adopting the above technical solution, this layout method can ensure a more uniform temperature distribution inside the entire reaction chamber, avoid local overheating or overcooling, and provide favorable conditions for the uniform deposition of granular silicon.

[0020] Preferably, the heating device further includes a water-cooling mechanism, which is arranged on the microwave heater and used to cool the internal components of the microwave heater.

[0021] By adopting the above technical solution, the water-cooling mechanism can timely remove the heat generated by the microwave heater, avoid local overheating, ensure the normal operation of its internal components, and extend the service life of the equipment.

[0022] Preferably, a reaction gas inlet and a fluidizing gas inlet are arranged at the bottom of the reaction chamber; and a gas distributor is also arranged inside the reaction chamber, and a silicon seed crystal feeding port and an exhaust port are arranged at the top of the reaction chamber.

[0023] By adopting the above technical solution, arranging the reaction gas inlet and the fluidizing inlet uniformly at the bottom of the fluidized bed can ensure the uniform fluidization of the silicon seed crystal, and the gas distributor can adjust the uniform distribution of the gas flow inside the fluidized bed.

[0024] In summary, the present application includes at least one of the following beneficial technical effects:

[0025] 1. Using the stirring device to stir the materials inside the reaction chamber effectively prevents the overheating of the silicon seed crystal and granular silicon at the bottom of the reactor, and at the same time can better maintain the fluidized state of the silicon particles in the heating section, promoting the full mixing reaction of the raw material gas with the silicon seed crystal or granular silicon, and improving the deposition efficiency and quality of granular silicon.

[0026] 2. The heating device adopts a combined method of a resistance heater and a microwave heater, achieving a fast and uniform heating effect, providing favorable conditions for the preparation of granular silicon;

[0027] 3. The detachable connection method of the reaction chamber and the stirring device and the reasonable layout of each inlet and outlet make the equipment convenient for installation and maintenance, and can meet the stable production requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic structural diagram of a fluidized bed device for preparing granular silicon by the silane method in an embodiment of the present application;

[0029] Reference numerals in the drawings: 1, reaction chamber; 11, inner cylinder; 12, outer cylinder; 121, thermal insulation layer; 13, reaction gas inlet; 14, fluidizing gas inlet; 15, gas distributor; 16, feeding port; 17, exhaust port; 2, stirring device; 21, stirring blades; 3, heating device; 31, resistance heater; 32, microwave heater; 33, water cooling mechanism. Detailed implementation manners

[0030] The following further elaborates on this application Figure 1 in conjunction with the accompanying drawings.

[0031] This embodiment discloses a fluidized bed device for preparing granular silicon by the silane method and its process flow. The device includes a reaction chamber 1 and a stirring device 2. The stirring device 2 is arranged on the bottom side of the reaction chamber 1 and includes rotatable stirring blades 21. The stirring blades 21 can be installed in the reaction chamber 1 through a stirring shaft, and the rotation of the stirring blades 21 is driven to continuously and effectively stir the materials inside the reaction chamber 1.

[0032] The stirring device 2 of this device is detachably connected to the side wall of the reaction chamber 1, which not only facilitates the daily maintenance and replacement of the stirring device 2, but also improves the maintainability of the device. The structure design of the reaction chamber 1 is optimized, specifically including two parts: an inner cylinder 11 and an outer cylinder 12. The inner cylinder 11 is composed of multiple cylinder segments spliced together, and this segmented design enables the height of the inner cylinder 11 to be flexibly adjusted according to actual needs. A thermal insulation layer 121 is added to the outer cylinder 12, and this design effectively reduces the heat loss during the operation of the device, thereby improving the overall energy utilization efficiency.

[0033] Preferably, the stirring device 2 can also be set in the form of magnetic stirring, and the form of the stirring blade can be frame type, folded blade type, spiral type, etc. In order to prevent the adhesion of materials to the blades during stirring, an isolation coating is specially provided on the surface of the stirring blades 21, and its material can be silica, ceramic, graphite, silicon, silicon nitride, silicon carbide, molybdenum, and polymer composite materials, etc.

[0034] In addition, this device is also equipped with a heating device 3, which is arranged on the outer wall of the inner cylinder 11 and is used to precisely heat the inside of the inner cylinder 11. The heating device 3 is composed of two parts: a resistance heater 31 and a microwave heater 32, ensuring the uniformity and efficiency of heating.

[0035] Furthermore, two groups of resistance heaters 31 are provided and distributed along the length direction of the inner cylinder 11, providing a uniform and stable heating environment for the reaction chamber 1. The microwave heater 32 is arranged between the two groups of resistance heaters 31, and by using the unique heating method of microwaves, rapid and uniform heating inside the materials is achieved.

[0036] To further enhance the safety and durability of the equipment, a water-cooling mechanism 33 is specifically added to the heating device 3. This water-cooling mechanism 33 is closely arranged on the microwave heater 32, and its main function is to continuously and effectively cool the working components inside the microwave heater 32. Through this design, the excess heat generated by the microwave heater 32 during operation can be taken away in a timely manner, thus effectively preventing the heater from being damaged due to overheating and significantly extending the service life of the equipment.

[0037] In the structural layout of the equipment, a reaction gas inlet 13 and a fluidizing gas inlet 14 are provided at the bottom of the reaction chamber 1. At the same time, a silicon seed crystal feeding port 16 and an exhaust port 17 are equipped at the top of the reaction chamber 1, greatly facilitating the feeding and exhaust operations.

[0038] During the production process of preparing granular silicon by the silane method using this equipment, first, an appropriate amount of silicon seed crystal is added to the reaction chamber 1 through the silicon seed crystal feeding port 16. Subsequently, necessary raw material gases such as silane are introduced into the reaction chamber 1 through the reaction gas inlet 13. The fluidizing gas is introduced through the fluidizing gas inlet 14 to fluidize the materials, so as to ensure the reaction rate. And in order to ensure the uniform distribution of the gas flow in the fluidized bed, a gas distributor 15 is also provided inside the fluidizing gas inlet 14.

[0039] Next, the stirring device 2 and the heating device 3 are started to comprehensively stir and heat the materials in the reaction chamber 1. During the reaction process, the operator can precisely control the fluidization state in the reaction chamber 1 by adjusting the fluidizing gas flow rate of the fluidizing gas inlet 14, thereby further optimizing the reaction conditions. When the reaction is completed, the heating device 3 and the stirring device 2 are turned off, and the unreacted raw material gases and the generated gases are discharged in a timely manner through the exhaust port 17.

[0040] The above are all the preferred embodiments of this application. The protection scope of this application is not limited by this. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A fluidized bed device for preparing granular silicon by a silane process, characterized in that: It comprises a reaction chamber (1) and a stirring device (2); the stirring device (2) is arranged on the bottom side of the reaction chamber (1) and is used to stir the material inside the reaction chamber (1).

2. The fluidized bed equipment for preparing granular silicon by the silane method according to claim 1, characterized in that: The stirring device (2) is detachably connected to the side wall of the reaction chamber (1); the stirring device (2) comprises a rotatably arranged stirring blade (21), and an isolation coating is provided on the surface of the stirring blade (21).

3. The fluidized bed equipment for preparing granular silicon by the silane method according to claim 1, characterized in that: The reaction chamber (1) comprises an inner cylinder (11) and an outer cylinder (12); the inner cylinder (11) comprises a plurality of cylinder segments, and the plurality of cylinder segments are spliced ​​together; and a heat-insulating layer (121) is provided on the outer cylinder (12).

4. The fluidized bed equipment for preparing granular silicon by the silane method according to claim 3, characterized in that: It also comprises a heating device (3), which is arranged on the outer wall of the inner cylinder (11) and is used to heat the interior of the inner cylinder (11).

5. The fluidized bed equipment for preparing granular silicon by the silane method according to claim 4, characterized in that: The heating device (3) comprises a resistance heater (31) and a microwave heater (32).

6. The fluidized bed equipment for preparing granular silicon by the silane method according to claim 5, characterized in that: The resistance heaters (31) are provided in two groups and are distributed along the length direction of the inner cylinder (11); the microwave heater (32) is provided between the two groups of resistance heaters (31).

7. The fluidized bed equipment for preparing granular silicon by the silane method according to claim 5, characterized in that: The heating device (3) further comprises a water cooling mechanism (33), wherein the water cooling mechanism (33) is arranged on the microwave heater (32) and is used to cool internal components of the microwave heater (32).

8. The fluidized bed equipment for preparing granular silicon by the silane method according to claim 1, characterized in that: The bottom of the reaction chamber (1) is provided with a reaction gas inlet (13) and a fluidizing gas inlet (14); a gas distributor (15) is also provided in the reaction chamber (1), and the top of the reaction chamber (1) is provided with a silicon seed crystal feeding port (16) and an exhaust port (17).

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