Reduction furnace structure

Abstract

The utility model discloses a reduction furnace structure, relates to the technical field of polycrystalline silicon production, and mainly aims to enable the appearance of finished polycrystalline silicon rods to be uniform and consistent. According to the main technical scheme, the reduction furnace structure comprises a base plate and a central feeding pipe, a plurality of first nozzles and a plurality of tail gas pipes are distributed on the circumference of the chassis; the lower end of the central feeding pipe is connected to the center of the base plate, and the upper end of the central feeding pipe is connected to the second nozzle.

Description

Technical Field

[0001] The utility model relates to the technical field of polysilicon production, in particular to a reduction furnace structure. Background Art

[0002] High-purity polysilicon is the main material for manufacturing solar cells. At present, the domestic production of high-purity polysilicon mainly adopts the Siemens improved process. The process principle is to introduce high-purity trichlorosilane and hydrogen into a reduction furnace in a certain ratio, and a reduction reaction occurs under 1080℃~1200℃ and 6bar conditions to generate high-purity polysilicon, while also producing by-products such as hydrogen chloride, silicon tetrachloride and dichlorosilane.

[0003] The reduction furnace feeding method is that the concentrated vaporized trichlorosilane is mixed with the high-temperature hydrogen passing through the flow regulating valve, and the gas mixture is further heated by the tail gas of the reduction furnace. The feed pipeline is directly connected to the feed nozzle on the chassis by several branch pipes, and the material is sprayed into the reduction furnace for reaction through the pressure difference before and after the nozzle. The feed nozzle on the chassis is strictly simulated and calculated during the equipment manufacturing. The nozzle is reasonably arranged in combination with the tail gas hole position, the relative distance from each pair of silicon rods, and the radiation area of ​​the ejected material, so that the mixture of high-purity trichlorosilane and hydrogen is sprayed into the reduction furnace and evenly dispersed, fully contacting and reacting with the silicon rods, so that the silicon rods can continue to operate under a stable airflow state.

[0004] In the reduction furnace, the heat of the silicon rod controlled by current is relatively consistent. The material is ejected from the bottom plate and gradually rises. While the material is constantly heated during the rising process, the material concentration is constantly weakening. When it reaches the top of the silicon rod, the temperature of the material is higher, and a temperature gradient appears from bottom to top, resulting in a rough appearance on the top of the silicon rod, commonly known as corn-shaped coral material, while the silicon rods in the middle and below are relatively dense. Utility Model Content

[0005] In view of this, the utility model provides a reduction furnace structure, the main purpose of which is to make the appearance of the finished polysilicon rods uniform.

[0006] In order to achieve the above purpose, the utility model mainly provides the following technical solutions:

[0007] The utility model provides a reduction furnace structure, which comprises: a bottom plate and a central feed pipe;

[0008] The chassis is provided with a plurality of first nozzles and a plurality of tailpipes distributed around its circumference;

[0009] The lower end of the central feed pipe is connected to the center of the bottom plate, and the upper end of the central feed pipe is connected to the second nozzle.

[0010] The purpose of the utility model and the solution to its technical problems can also be further achieved by adopting the following technical measures.

[0011] Optionally, the diameter of the central feed pipe gradually decreases from bottom to top.

[0012] Optionally, the height of the central feed tube is greater than half of the height of the silicon core and less than the height of the silicon core.

[0013] Optionally, the second nozzle is threadedly connected to the upper end of the central feed pipe.

[0014] Optionally, the plurality of silicon cores are evenly distributed on the circumferences of a plurality of concentric circles, and the circumferences of the plurality of first nozzles are evenly distributed between two adjacent concentric circles.

[0015] Optionally, the plurality of tailpipes are evenly distributed on the edge of the chassis.

[0016] Optionally, an annular feed pipe is further included. An annular material cavity is attached to the lower surface of the chassis. The annular feed pipe is connected to the material cavity through a plurality of branch pipes, and a plurality of the first nozzles are connected to the material cavity.

[0017] Optionally, a cooling water channel is formed in the chassis.

[0018] Optionally, the central feed pipe is made of 800H, 8810 or 8120 material.

[0019] By means of the above technical solution, the utility model has at least the following advantages:

[0020] When the reduction furnace is running, a part of the material enters the reduction furnace from multiple first nozzles and is dispersed around the silicon core. This part of the material rises along the length of the silicon core and gradually heats up. The other part of the material rises along the central feed pipe and is ejected from the second nozzle. The temperature and concentration of the two parts of the material are the same. The material ejected from the second nozzle is reflected to the top of the silicon core through the inner wall of the top of the bell jar to supplement the material concentration at the top of the silicon core. At the same time, the top material flows back downward and flows out of the reduction furnace through the tail gas pipe, taking away the heat from the top of the silicon rod and eliminating the temperature gradient of the silicon rod from bottom to top. At the same time, the material ejected from the second nozzle also supplements the material concentration at the top of the reduction furnace, making the top of the silicon rod grow smooth and dense, eliminating the corn-shaped coral material on the top of the silicon rod, and increasing the proportion of dense material. The bottom and top are fed at the same time, the material has good fluidity, and the gas field and thermal field are uniform, which improves the operating stability of the reduction furnace and the uniformity and consistency of the appearance of the finished polysilicon rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A side view of a reduction furnace structure provided by an embodiment of the utility model;

[0022] Figure 2 A top view of a reduction furnace structure chassis provided in an embodiment of the utility model.

[0023] The reference numerals in the drawings of the specification include: chassis 1, tail gas pipe 2, first nozzle 3, silicon core 4, bell jar 5, central feed pipe 6, second nozzle 7, material chamber 8. DETAILED DESCRIPTION

[0024] In order to further explain the technical means and effects adopted by the utility model to achieve the predetermined utility model purpose, the specific implementation methods, structures, features and effects of the utility model application are described in detail below in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.

[0025] The utility model is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0026] like Figure 1 and Figure 2 As shown, an embodiment of the utility model provides a reduction furnace structure, which includes: a bottom plate 1 and a central feed pipe 6;

[0027] The chassis 1 is provided with a plurality of first nozzles 3 and a plurality of tailpipes 2 distributed around the circumference;

[0028] The lower end of the central feed pipe 6 is connected to the center of the chassis 1 , and the upper end of the central feed pipe 6 is connected to the second nozzle 7 .

[0029] The working process of a reduction furnace structure is as follows:

[0030] When the reduction furnace is running, a part of the material enters the reduction furnace from the multiple first nozzles 3 and is dispersed around the silicon core 4. This part of the material rises along the length direction of the silicon core 4 and gradually heats up. The other part of the material rises along the central feeding pipe 6 and is ejected from the second nozzle 7. The temperature and concentration of the two parts of the material are the same. The material ejected from the second nozzle 7 is reflected to the top of the silicon core 4 through the inner wall of the top of the bell jar 5 to supplement the material concentration at the top of the silicon core 4. At the same time, the top material flows back downward and flows out of the reduction furnace through the tail gas pipe 2, taking away the heat at the top of the silicon rod, eliminating the temperature gradient of the silicon rod from bottom to top. At the same time, the material ejected from the second nozzle 7 also supplements the material concentration at the top of the reduction furnace, so that the material concentration above and below the silicon rod is balanced, so that the top of the silicon rod grows smooth and dense, the corn-shaped coral material on the top of the silicon rod is eliminated, and the proportion of dense silicon material is increased. The bottom and the top are fed at the same time, the material fluidity is good, the gas field and the thermal field are uniform, the operation stability of the reduction furnace is improved, and the appearance uniformity and consistency of the finished polysilicon rod are improved.

[0031] Specifically, the above-mentioned feeding method makes the heat field in the furnace uniform, the top of the silicon rod grows densely, and there is no coral material, which improves the value of the product;

[0032] The materials are fed from the bottom and the top at the same time, the material flow in the furnace is good, the gas field is stable, and the stable operation of the reduction furnace is improved;

[0033] The silicon rod has a smooth and dense appearance, and the whole silicon rod can be crushed without the need to classify dense materials, cauliflower materials, and coral materials, thus reducing the workload.

[0034] Specifically, the central feed pipe 6 is located at the center of the chassis 1 and will not affect the robot arm in removing the silicon rods.

[0035] Specifically, multiple silicon core concentric circles are distributed on the chassis, divided into an outer ring, a middle ring, an inner ring and a center ring.

[0036] Specifically, the bell jar is a double-layer jacketed bell jar, and circulating cooling water is inside the jacket to take away the radiation heat from the silicon rod to the bell jar.

[0037] Specifically, the space in the center area of ​​the center ring silicon core is large, and the center feed pipe 6 will not contact the silicon core, will not cause grounding and furnace shutdown, and will not affect the disassembly of the silicon rods.

[0038] In a specific embodiment, the diameter of the central feeding pipe 6 gradually decreases from bottom to top.

[0039] In this embodiment, specifically, the diameter of the central feed pipe 6 gradually decreases from bottom to top, so that the central feed pipe 6 itself has the function of basic support.

[0040] like Figure 1 As shown, in a specific embodiment, the height of the central feed pipe 6 is greater than half of the height of the silicon core 4 and less than the height of the silicon core 4 .

[0041] In this embodiment, since the second nozzle 7 is connected to the upper end of the central feed pipe 6, the starting position of the second nozzle 7 spraying the material is higher than half the height of the silicon core 4, so the material concentration in the upper half of the silicon core 4 can be replenished in time.

[0042] like Figure 1 As shown, in a specific embodiment, the second nozzle 7 is threadedly connected to the upper end of the central feed pipe 6 .

[0043] In this embodiment, specifically, the second nozzle 7 is threadedly connected to the upper end of the central feed pipe 6 , which facilitates the disassembly and replacement of the second nozzle 7 .

[0044] like Figure 1 and Figure 2 As shown, in a specific embodiment, a plurality of silicon cores 4 are evenly distributed on the circumferences of a plurality of concentric circles, and a plurality of the first nozzles 3 are evenly distributed on the circumferences between two adjacent concentric circles.

[0045] In this embodiment, specifically, multiple first nozzles 3 are evenly distributed between two adjacent concentric circles, so that the probability of the material sprayed from the first nozzle 3 contacting the inner circumferential silicon core 4 and the outer circumferential silicon core 4 during the rising process is the same, thereby causing the diameters of the silicon rods in adjacent circles to increase synchronously.

[0046] like Figure 1 and Figure 2 As shown, in a specific embodiment, the plurality of tailpipes 2 are evenly distributed on the edge of the chassis 1 .

[0047] In this embodiment, specifically, the tail gas of the reacted material must diffuse to the edge of the chassis 1 before it can be discharged from the reduction furnace through the tail gas pipe 2, so as to extend the residence time of the material in the reduction furnace as much as possible, thereby increasing the percentage of material reaction.

[0048] like Figure 1 and Figure 2 As shown, in a specific embodiment, it also includes an annular feed pipe. An annular material chamber 8 is attached to the lower surface of the chassis 1. The annular feed pipe is connected to the material chamber 8 through a plurality of branch pipes. A plurality of the first nozzles 3 are connected to the material chamber 8.

[0049] In this embodiment, specifically, the mixture of trichlorosilane and hydrogen flows through the annular feed pipe, the branch pipe and the annular material chamber 8 in sequence before reaching the first nozzle 3, so that the material is fully mixed in the annular feed pipe and the material chamber 8 before being ejected through the first nozzle 3, and the pressure of each nozzle is relatively balanced and stable, thereby improving the uniformity of the mixture of trichlorosilane and hydrogen in the reduction furnace.

[0050] In a specific implementation, a cooling water channel is formed in the chassis 1 .

[0051] In this embodiment, specifically, the circulating water in the cooling water channel takes away the heat of the chassis 1 in time to prevent the chassis 1 from being damaged by high temperature.

[0052] In a specific implementation, the central feed pipe 6 is made of 800H, 8810 or 8120 material.

[0053] In the present embodiment, specifically, the central feed pipe 6 is made of 800H, 8810 or 8120 material, which can withstand the high temperature environment in the reduction furnace, ensuring that the central feed pipe 6 can operate for a long time.

[0054] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A reduction furnace structure, characterized in that: include: A chassis, wherein a plurality of first nozzles and a plurality of tailpipes are distributed around the chassis, and a bell jar is placed on the upper surface of the chassis; A central feed pipe, wherein the lower end of the central feed pipe is connected to the center of the chassis, the upper end of the central feed pipe is connected to the second nozzle, the height of the central feed pipe is greater than half of the height of the silicon core and less than the height of the silicon core, and the material sprayed from the second nozzle is reflected to the top of the silicon core through the inner wall of the top of the bell jar.

2. The reduction furnace structure according to claim 1, characterized in that: From bottom to top, the diameter of the central feed pipe gradually decreases.

3. The reduction furnace structure according to claim 1, characterized in that: The second nozzle is threadedly connected to the upper end of the central feed pipe.

4. The reduction furnace structure according to any one of claims 1 to 3, characterized in that: The plurality of silicon cores are evenly distributed on the circumferences of a plurality of concentric circles, and the circumferences of the plurality of first nozzles are evenly distributed between two adjacent concentric circles.

5. The reduction furnace structure according to any one of claims 1 to 3, characterized in that: The plurality of tailpipes are evenly distributed on the edge of the chassis.

6. The reduction furnace structure according to any one of claims 1 to 3, characterized in that: It also includes an annular feed pipe. An annular material cavity is attached to the lower surface of the chassis. The annular feed pipe is connected to the material cavity through a plurality of branch pipes. A plurality of the first nozzles are connected to the material cavity.

7. The reduction furnace structure according to any one of claims 1 to 3, characterized in that: A cooling water flow channel is formed in the chassis.

8. The reduction furnace structure according to any one of claims 1 to 3, characterized in that: The central feed pipe is made of 800H, 8810 or 8120 material.

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