Cyclone dust collector for polycrystalline silicon production system

Abstract

The utility model relates to the technical field of polycrystalline silicon production, and discloses a cyclone dust collector for a polycrystalline silicon production system, which comprises a dust collector body consisting of a first straight cylinder and a first conical cylinder, and a connecting flange arranged at the tail part of the dust collector body, wherein the first straight cylinder and the first conical cylinder are sequentially connected from top to bottom, the connecting flange is connected with the tail of the first conical cylinder in a welded mode, a feeding port and a first discharging port are formed in the first straight cylinder, and a lower port of the connecting flange is a second discharging port; wear-resisting lining plates are arranged on the inner wall of the first straight cylinder and the inner wall of the first conical cylinder, a wear-resisting lining ring is embedded in a flange hole of the connecting flange, and the end of the wear-resisting lining ring abuts against the tail of the wear-resisting lining plate in the first conical cylinder. According to the utility model, the scouring resistance and the abrasion resistance of the connecting flange at the weak position of the cyclone dust collector are improved, so that the service life of the whole cyclone dust collector is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of polysilicon production, in particular to a cyclone dust collector used in a polysilicon production system. Background Art

[0002] Polycrystalline silicon is the fundamental material for photovoltaic solar cells. Monocrystalline silicon, produced from electronic-grade polycrystalline silicon, is also a fundamental material for the electronic information industry, serving as the raw material for large-scale integrated circuits, semiconductor discrete components, and power electronic devices. Currently, the mainstream technology for polysilicon production is a modified Siemens process. For every kilogram of polysilicon produced, approximately 20 kilograms of silicon tetrachloride (SiCl2) is produced as a byproduct. This byproduct is primarily converted using SiCl2 cold hydrogenation technology. This conversion process primarily takes place in a cold hydrogenation reactor, where silicon powder is added. As the reaction proceeds, the silicon powder gradually shrinks and is carried away by the reaction gases.

[0003] The exhaust gases from the hydrogenation reactor are typically treated in a cyclone dust collector. The gases entering the cyclone contain gaseous chlorosilane, gaseous hydrogen, and solid silicon powder. During operation, the dust collector, through the rotational motion caused by the tangential introduction of the airflow, throws solid particles with greater inertial centrifugal force toward the outer wall, thereby separating the gaseous and solid phases. The solid phase sinks due to gravity, while the gas phase is discharged from the top.

[0004] A cyclone dust collector typically consists of a dust collector body and a connecting flange welded to the rear of the body. The inner wall of the dust collector body is welded to the cylinder using a tortoise-shell mesh. The polygonal cavity is welded with multiple transverse connectors. Finally, the tortoise-shell mesh is filled with wear-resistant material, forming a cohesive internal wear-resistant lining. This ensures both overall wear resistance and a secure fit with the shell. Long-term operation of the equipment has proven that the structure and material of the tortoise-shell mesh corundum ensure long-term stable operation. However, the connecting flange at the bottom of the unit is currently the weakest point of the equipment. Due to the narrow internal space of the connecting flange, existing tortoise-shell mesh corundum wear-resistant linings are prone to machining defects, creating a weak point in the equipment. Over time, the lining inside the flange hole is prone to localized cracking. This causes vortices to form in the cracked lining, rapidly eroding the wear-resistant material and the shell, ultimately leading to leakage of the internal media, resulting in serious, high-risk media leaks. Furthermore, this area cannot currently be effectively detected through thickness measurement, making it difficult to effectively manage the risk. Summary of the Invention

[0005] In order to solve the problems and shortcomings existing in the above-mentioned prior art, the utility model proposes a cyclone dust collector for a polysilicon production system. The utility model improves the wear-resistant structure at the end connecting flange of the cyclone dust collector, thereby improving the erosion resistance of the connecting flange, thereby increasing the service life of the entire cyclone dust collector.

[0006] In order to achieve the above-mentioned purpose of the invention, the technical solution of the present utility model is as follows:

[0007] The utility model proposes a cyclone dust collector for a polysilicon production system, wherein the dust collector comprises a dust collector body, which comprises a first straight cylinder and a first conical cylinder from top to bottom, a connecting flange is welded at the tail of the first conical cylinder, a feed port and a first discharge port are provided on the first straight cylinder, the feed port is connected to the cold hydrogenation reactor in the cold hydrogenation process, and the lower port of the connecting flange is the second discharge port; the inner walls of the first straight cylinder and the first conical cylinder are provided with wear-resistant linings, a wear-resistant lining ring is embedded in the flange hole of the connecting flange, and the end of the wear-resistant lining ring abuts against the tail of the wear-resistant lining in the first conical cylinder.

[0008] Preferably, a high-temperature resistant filler is filled between the wear-resistant lining ring and the inner wall of the flange hole.

[0009] Preferably, a retaining ring is further provided in the flange hole of the connecting flange, and the retaining ring is located below the wear-resistant lining ring.

[0010] Preferably, the retaining ring is welded to the inner wall of the flange hole.

[0011] Preferably, the wear-resistant lining ring is a metal ceramic lining ring.

[0012] Preferably, the cyclone dust collector also includes an ash hopper, which is located between the first cone and the connecting flange, and includes a second straight cylinder and a second cone from top to bottom, the end of the second straight cylinder is connected to the tail of the first cone, and the connecting flange is welded to the tail of the second cone.

[0013] Preferably, the inner walls of the second straight cylinder and the second conical cylinder are provided with wear-resistant lining plates which are the same as those of the inner walls of the first straight cylinder and the first conical cylinder.

[0014] Beneficial effects of the utility model:

[0015] 1. The wear-resistant lining plate in the dust collector body of the present invention and the wear-resistant lining ring in the flange hole of the connecting flange are made of different materials and methods, and the two wear-resistant structures are independent of each other. After the wear-resistant lining ring is integrally sintered and formed on the outside, it is clamped and assembled in the flange hole of the connecting flange. The wear-resistant lining ring does not have any processing and manufacturing defects, is extremely difficult to be worn by silicon powder, and has better overall wear resistance. Therefore, the present invention improves the erosion and wear resistance of the connecting flange, thereby increasing the service life of the entire cyclone dust collector; it also reduces the cost of replacing equipment and avoids safety accidents caused by leakage of high-risk media.

[0016] 2. The wear-resistant lining ring at the connecting flange of the utility model is detachably connected to the flange hole of the connecting flange by means of clearance fit. Therefore, even if the wear-resistant lining ring is eroded and broken, a new wear-resistant lining ring can be replaced without reducing the overall service life of the cyclone dust collector.

[0017] 3. The utility model fills the outer wall of the wear-resistant liner ring and the inner wall of the flange hole with high-temperature resistant ceramic particle glue and other fillers. The fillers are used to fill and compensate for the gap between the two, prevent the wear-resistant liner ring from shaking, and avoid the wear-resistant liner ring from being damaged by impact or silicon powder from entering the annulus between the wear-resistant liner ring and the flange hole and scouring the shell.

[0018] 4. The utility model provides a retaining ring with the same inner and outer diameters as the wear-resistant lining ring below the wear-resistant lining ring. The retaining ring supports the lining ring to prevent it from falling and falling out of the flange hole.

[0019] 5. The utility model provides an ash hopper below the first cone, with a connecting flange welded to the rear end of the hopper. The ash hopper decelerates the high-speed silicon powder being separated, reducing erosion on the equipment. It can also store a small amount of silicon powder, reducing its overflow from the first discharge port and reducing the amount of silicon powder carried over to the back-end system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The foregoing and following detailed description of the present invention will become more clear when read in conjunction with the following drawings, in which:

[0021] Figure 1 This is a schematic diagram of the structure of the cyclone dust collector of the utility model;

[0022] In the picture:

[0023] 1. First straight cylinder; 2. First conical cylinder; 3. Connecting flange; 4. Feed inlet; 6. Second discharge outlet; 7. Wear-resistant lining plate; 8. Wear-resistant lining ring; 9. Retaining ring; 10. Second straight cylinder; 11. Second conical cylinder. DETAILED DESCRIPTION

[0024] In order to help those skilled in the art better understand the technical solutions of the present invention, the following will further illustrate the technical solutions for achieving the purpose of the present invention through several specific embodiments. It should be noted that the technical solutions claimed for protection by the present invention include but are not limited to the following embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0025] Example 1

[0026] As a basic embodiment of the present invention, this embodiment discloses a cyclone dust collector for a polysilicon production system. Figure 1 As shown, the cyclone dust collector includes a dust collector body composed of a first straight cylinder 1 and a first conical cylinder 2, the first straight cylinder 1 and the first conical cylinder 2 are connected in sequence from top to bottom, and the tail of the first conical cylinder 1 is provided with a connecting flange 3, which is fixed to the tail of the first conical cylinder 2 by welding; the upper end of the first straight cylinder 1 is respectively provided with a feed port 4 and a first discharge port, and the lower end of the tail of the connecting flange 3 is the second discharge port 6 of the dust collector, wherein the feed port 4 is connected to the hydrogenation reactor, the first discharge port is connected to the silicon powder filter for re-filtering the silicon powder, and the second discharge port 6 is connected to the silicon powder collection tank for receiving the separated silicon powder; the inner wall of the first straight cylinder 1 and the first conical cylinder 2 is provided with a wear-resistant lining 7, the center of the connecting flange 3 is provided with a flange hole, and a wear-resistant lining ring 8 is embedded in the flange hole, and the end of the wear-resistant lining ring abuts against the tail of the wear-resistant lining 7 in the upper first conical cylinder 2.

[0027] In the embodiment described in the present invention, the wear-resistant lining plate 7 in the first straight cylinder 1 and the second conical cylinder 2 is an integrated structure, usually made of tortoise shell corundum. The specific structure and manufacturing process of the wear-resistant lining plate 7 are as follows:

[0028] First, the tortoise shell mesh is welded and fixed on the inner wall of the straight cylinder and the conical cylinder, and its polygonal cavity is welded with multiple fixed transverse connectors. Finally, the tortoise shell mesh is filled with wear-resistant material (usually corundum), and finally the internal wear-resistant lining on the straight cylinder and the conical cylinder forms a whole, that is, the tortoise shell mesh corundum wear-resistant lining.

[0029] Due to the narrow interior space of the connecting flange 3, the tortoise-shell corundum wear-resistant lining is prone to machining defects during processing, resulting in a structurally weak spot in the connecting flange 3. The tortoise-shell corundum in this spot is easily damaged by high-speed solid-phase silicon powder erosion, ultimately leading to leakage of the entire internal medium of the cyclone dust collector, causing serious high-risk medium leakage accidents and shortening the service life of the entire equipment. Therefore, the present invention improves the wear-resistant structure within the flange hole of the connecting flange 3. In the embodiment depicted in the present invention, the wear-resistant lining ring 8 provided in the flange hole and the wear-resistant lining plate 7 provided on the inner wall of the dust collector body are independent, separate structures and are manufactured using different manufacturing processes and materials. The wear-resistant lining ring 8 can be manufactured from a wear-resistant material such as cermet (e.g., carbide-based cermet, nitride-based cermet, etc.). The wear-resistant lining ring 8 is separately fired and formed as a whole externally, and then assembled into the flange hole of the connecting flange 3, making close contact with the inner wall of the flange hole.

[0030] It can be understood that the wear-resistant lining ring 8 is clearance-matched with the flange hole of the connecting flange 3 . During the manufacturing process, the wear-resistant lining ring 8 is processed according to the aperture of the flange hole to minimize the gap between the two.

[0031] In the embodiment described in the present invention, in addition to being connected to the silicon powder filter, the first discharge port can also be connected to the second-stage cyclone dust collector to perform two-stage cyclone separation to further remove silicon powder in the gas.

[0032] In the embodiment described in the present invention, the gas in the hydrogenation reactor is cooled by a two-stage heat exchanger and then transported to a cyclone dust collector through a feed port for treatment. The substances entering the cyclone dust collector include gaseous chlorosilane, gaseous hydrogen, and solid silicon powder. When the dust collector is working, the rotational motion caused by the tangential introduction of the airflow causes the solid particles with greater inertial centrifugal force to be thrown toward the outer wall, thereby separating the gaseous medium and the solid medium. The solid silicon powder sinks due to gravity and is discharged into the silicon powder collection tank through the second discharge port at the rear connection flange of the dust collector, while the remaining gaseous chlorosilane and hydrogen are discharged into the silicon powder filter or the second-stage cyclone dust collector through the first discharge port at the top.

[0033] Example 2

[0034] This embodiment discloses a cyclone dust collector for a polysilicon production system. Based on Example 1, to enhance the secure installation of wear-resistant lining ring 8 within the flange hole, this embodiment incorporates a high-temperature-resistant filler, such as ceramic granular glue, between the outer wall of wear-resistant lining ring 8 and the inner wall of the flange hole. The filler fills the gap between wear-resistant lining ring 8 and the flange hole, preventing wear-resistant lining ring 8 from swaying or rotating within the flange hole.

[0035] Furthermore, a retaining ring 9 is provided in the flange hole of the connecting flange 3 and is located below the wear-resistant lining ring. The tail of the wear-resistant lining ring 8 abuts against the upper surface of the retaining ring 9, and the retaining ring 9 supports the wear-resistant lining ring 8 to prevent it from falling and falling out of the flange hole.

[0036] It is understood that the inner and outer diameters of the retaining ring 9 are the same as those of the wear-resistant liner 8 and should be as short as possible to prevent silicon powder erosion. The retaining ring 9 is welded to the inner wall of the flange hole using intermittent welding to prevent thermal deformation. Therefore, the retaining ring material should be consistent with the connecting flange material to ensure weldability and avoid abnormalities caused by welding dissimilar steels.

[0037] It can be understood that the retaining ring 9 is arranged at the lowermost end of the flange hole and cannot exceed the lower end surface of the flange hole. At most, it is flush with the lower end surface of the flange hole.

[0038] Example 3

[0039] This embodiment discloses a cyclone dust collector for a polysilicon production system. Based on Example 1 or Example 2, the cyclone dust collector also includes an ash hopper, which is located between the first cone 2 and the connecting flange 3. From top to bottom, it includes a second straight cylinder 10 and a second cone 11. The end of the second straight cylinder 10 is connected to the tail of the first cone 1, and the end of the second cone 11 is connected to the tail of the second straight cylinder 10. The connecting flange 3 is welded to the tail of the second cone 1.

[0040] In the embodiment described in the present invention, the ash hopper can not only slow down the high-speed silicon powder separated from the dust collector body above, thereby reducing the scouring of the equipment, but also store a small amount of silicon powder, reduce the overflow of silicon powder from the first discharge port, and reduce the amount of silicon powder carried by the back-end system.

[0041] Furthermore, the inner walls of the second straight cylinder 10 and the second tapered cylinder 11 are provided with wear-resistant lining plates 7 that are the same as the inner walls of the first straight cylinder 1 and the first tapered cylinder 2 .

[0042] It is understood that during processing, the wear-resistant lining 7 provided within the hopper can be integrally formed with the wear-resistant lining 7 within the dust collector body. That is, during processing, the wear-resistant lining 7 within the first straight cylinder 1, first conical cylinder 2, second straight cylinder 10, and second conical cylinder 11 of the entire cyclone dust collector are all integrally formed from the same material, resulting in a single, integrated wear-resistant structure. The specific processing and forming methods can be referred to the method described in Example 1.

[0043] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present invention.

[0044] It should also be noted that, in the description of this utility model, unless otherwise expressly specified or limited, the terms "disposed," "installed," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this utility model based on the specific circumstances.

[0045] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention falls within the scope of protection of the present invention.

Claims

1. A cyclone dust collector for a polysilicon production system, characterized in that: The dust collector body comprises a first straight cylinder (1) and a first conical cylinder (2) from top to bottom, the tail of the first conical cylinder (2) is welded with a connecting flange (3), a feed port (4) and a first discharge port are provided on the first straight cylinder (1), the feed port (4) is connected to the hydrogenation reactor, and the lower end of the connecting flange (3) is the second discharge port (6); the inner walls of the first straight cylinder (1) and the first conical cylinder (2) are provided with a wear-resistant lining (7), a wear-resistant lining ring (8) is embedded in the flange hole of the connecting flange (3), and the end of the wear-resistant lining ring (8) abuts against the tail of the wear-resistant lining (7) in the first conical cylinder (2).

2. The cyclone dust collector for a polysilicon production system according to claim 1, characterized in that: A high-temperature resistant filler is filled between the wear-resistant lining ring (8) and the inner wall of the flange hole.

3. The cyclone dust collector for a polysilicon production system according to claim 1, characterized in that: A retaining ring (9) is further provided in the flange hole of the connecting flange (3), and the retaining ring (9) is located below the wear-resistant lining ring (8).

4. The cyclone dust collector for a polysilicon production system according to claim 3, characterized in that: The retaining ring (9) is welded to the inner wall of the flange hole.

5. The cyclone dust collector for a polysilicon production system according to claim 1, characterized in that: The wear-resistant lining ring (8) is a metal ceramic lining ring.

6. The cyclone dust collector for a polysilicon production system according to claim 1, characterized in that: The cyclone dust collector further comprises an ash hopper, which is located between the first cone (2) and the connecting flange (3), and comprises, from top to bottom, a second straight cylinder (10) and a second cone (11), the end of the second straight cylinder (10) being connected to the tail of the first cone (2), and the connecting flange (3) being welded to the tail of the second cone (11).

7. The cyclone dust collector for a polysilicon production system according to claim 6, characterized in that: The inner walls of the second straight cylinder (10) and the second conical cylinder (11) are provided with wear-resistant lining plates (7) identical to the inner walls of the first straight cylinder (1) and the first conical cylinder (2).

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