High-temperature tail gas pipeline assembly for polycrystalline silicon reduction furnace

Abstract

The utility model discloses a high-temperature tail gas pipeline assembly for a polycrystalline silicon reduction furnace, which comprises a square coil pipe and an outer jacketed pipe, and a steering wheel pipe is arranged on a skid top cover in the reduction furnace through a bracket supporting beam; the shape of the outer jacketed pipe is consistent with that of the square coil pipe, and the outer jacketed pipe is arranged on the outer periphery of the square coil pipe in a sleeving mode. The square coil pipe comprises an upper-layer square pipe, a middle-layer square pipe and a lower-layer square pipe, and the upper-layer square pipe, the middle-layer square pipe and the lower-layer square pipe are arranged in an up-down right corresponding mode. In a limited space, the cooling area of the outlet tail gas pipeline of the reduction furnace is increased, and the heat exchange effect is enhanced in the limited space; and by adopting a spatial square structure, the phenomenon of stress concentration of the coil pipe is improved, the service life is prolonged, and long-period safe and stable operation of the tail gas pipeline of the high-temperature reduction furnace is ensured.

Description

Technical Field

[0001] This utility model belongs to the technical field of cooling device for reduction tail gas of polycrystalline silicon reduction furnace, and specifically relates to a high-temperature tail gas pipeline assembly for polycrystalline silicon reduction furnace. Background Technology

[0002] Polysilicon is a key material for manufacturing high-tech products such as computer chips, solar panels, and sensors. Domestic production of rod-shaped silicon largely employs the modified Siemens process, with the reduction furnace being the core equipment in polysilicon production, producing the final product. The furnace temperature is approximately 1050 degrees Celsius, while the exhaust gas temperature is around 700 degrees Celsius. To better recover energy, hot water is typically used to cool the high-temperature exhaust gas, followed by flash evaporation to recover heat. Exhaust gas cooling usually employs a jacketed cooling system, with a hot water jacket exchanging heat with the exhaust gas.

[0003] The exhaust gas outlet temperature is high, and in engineering, it is necessary to collect the heat from the exhaust gas pipes for use in subsequent production in the factory, which is energy-saving and environmentally friendly. However, the space available for exhaust gas pipes is limited. How to collect heat within a limited space while simultaneously meeting the pipe stress requirements is a challenge in existing exhaust gas pipe designs.

[0004] Currently, polysilicon plants have put exhaust gas cooling coils into use, most of which are serpentine coil structures. These structures are complex and stress is easily concentrated. The pipes along the medium flow direction have both up and down sections, forming multiple pockets and resulting in significant medium resistance loss inside the pipes. Moreover, since the exhaust gas contains a small amount of silicon powder, the silicon powder tends to accumulate at low points, which may cause blockages. Summary of the Invention

[0005] The purpose of this invention is to overcome the technical defects of existing technologies, such as stress concentration, large resistance loss, and easy blockage, and to provide a cooling coil for the tail gas outlet of a reduction conversion furnace.

[0006] To achieve the above objectives, this utility model provides a high-temperature exhaust gas pipeline assembly for a polycrystalline silicon reduction furnace, comprising a square coil and an outer jacket. The square coil is arranged on the skid top cover inside the reduction furnace by a support beam. The outer jacket has the same shape as the square coil and is fitted around the outer periphery of the square coil. The square coil includes an upper square tube, a middle square tube, and a lower square tube, which are arranged vertically in a symmetrical manner.

[0007] Furthermore, the upper square tube includes four horizontal straight pipes and three horizontal elbows. The four horizontal straight pipes form a square structure through the three horizontal elbows. The free end of one of the horizontal straight pipes is connected to one end of the inlet lower vertical pipe through a vertical elbow. The other end of the inlet lower vertical pipe is connected to one end of the outwardly extending inlet horizontal straight pipe through a vertical elbow. The other end of the inlet horizontal straight pipe is an inlet flange.

[0008] The middle layer square tube includes four horizontal straight pipes and three horizontal elbows. The four horizontal straight pipes form a square structure through the three horizontal elbows. The free end of one of the horizontal straight pipes is connected to the free end of the horizontal straight pipe at the other end of the upper layer square tube through a vertical elbow.

[0009] The lower square pipe consists of three horizontal straight pipes and two horizontal elbows. The three horizontal straight pipes are connected by the two horizontal elbows. The free end of one of the horizontal straight pipes is connected to the free end of the horizontal straight pipe at the other end of the middle square pipe through a vertical elbow. The horizontal straight pipe at the other end is connected to one end of the horizontal straight pipe inside the outlet through a horizontal elbow. The other end of the horizontal straight pipe inside the outlet is connected to one end of the lower vertical pipe at the outlet through a vertical elbow. The other end of the lower vertical pipe at the outlet is the outlet flange.

[0010] Furthermore, the outer jacket is a two-section heat exchange structure, which is divided into two sections by a jacket flange. Each section of the outer jacket is welded to the jacket flange to form a closed hot water circulation space. Each section of the outer jacket is provided with a hot water inlet and a hot water outlet.

[0011] Furthermore, baffles are installed every 2-4m between the outer sleeve and the square coil. One end of the baffle is welded to the outer wall of the square coil, and the other end of the baffle is left with a distance from the inner wall of the outer sleeve.

[0012] Furthermore, each radial section of the square coil is uniformly provided with 3 to 4 baffles.

[0013] Furthermore, each of the upper, middle, and lower square tubes has a bracket welded to both ends of a horizontal straight tube on the same side of its length direction. The brackets on the same side and at the same end are arranged in a straight line and rooted on the same support beam.

[0014] Furthermore, the lower vertical pipe of the inlet is welded with two supports, which are arranged in a straight line and rooted on the same support beam.

[0015] Furthermore, the outer sleeve has a diameter 2 inches larger than that of the square coil.

[0016] Furthermore, both the horizontal and vertical elbows are 3D elbows.

[0017] Compared with the prior art, the beneficial effects of this utility model are as follows: This utility model increases the cooling area of ​​the tail gas pipeline at the outlet of the reduction furnace within a limited space, thereby enhancing the heat exchange effect within the limited space; the adoption of a spatial square structure improves the phenomenon of stress concentration in the coil, extends the service life, and ensures the long-term safe and stable operation of the tail gas pipeline of the high-temperature reduction furnace. Attached Figure Description

[0018] Figure 1 This is a front view schematic diagram of the high-temperature exhaust gas pipeline assembly for the polycrystalline silicon reduction furnace of this utility model;

[0019] Figure 2 for Figure 1 A top-down view;

[0020] Figure 3 for Figure 1 Schematic diagram of a square coil;

[0021] Figure 4 for Figure 2 A schematic diagram of BB. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1 , 2 The high-temperature exhaust gas pipeline assembly for the polysilicon reduction furnace includes a square coil 1 and an outer jacket 2. The square coil 1 is arranged on the skid top cover 6 inside the reduction furnace via a support beam 9. The outer jacket 2 has the same shape as the square coil 1 and is fitted around the outer periphery of the square coil 1. Figure 4 As shown, the square coil 1 includes an upper square tube, a middle square tube, and a lower square tube. The upper, middle, and lower square tubes are arranged in a vertically symmetrical manner. This spatial square structure can effectively reduce the space required for pipe arrangement, increase the heat exchange effect, and reduce the drop in pipeline resistance. The outer jacket 2 is a jacket used for heat exchange of the square coil 1, and therefore, its diameter is 2 inches larger than that of the square coil.

[0024] The upper square pipe includes four horizontal straight pipes 14 and three horizontal elbows 3. The four horizontal straight pipes 14 form a square structure through the three horizontal elbows 3. The free end of one of the horizontal straight pipes 14 is connected to one end of the inlet lower vertical pipe 15 through a vertical elbow 4. The other end of the inlet lower vertical pipe 15 is connected to one end of the outwardly extending inlet horizontal straight pipe 17 through a vertical elbow 4. The other end of the inlet horizontal straight pipe 17 is an inlet flange 7.

[0025] The middle layer square tube includes four horizontal straight pipes 14 and three horizontal elbows 3. The four horizontal straight pipes 14 form a square structure through the three horizontal elbows 3. The free end of one of the horizontal straight pipes 14 is connected to the free end of the other horizontal straight pipe 14 of the upper layer square tube through a vertical elbow 4.

[0026] The lower square pipe includes three horizontal straight pipes 14 and two horizontal elbows 3. The three horizontal straight pipes 14 are connected by the two horizontal elbows 3. The free end of one of the horizontal straight pipes 14 is connected to the free end of the other horizontal straight pipe 14 of the middle square pipe through a vertical elbow 4. The other horizontal straight pipe 14 is connected to one end of the outlet inner horizontal straight pipe 18 through a horizontal elbow 19. The other end of the outlet inner horizontal straight pipe 18 is connected to one end of the outlet lower vertical pipe 16 through a vertical elbow 4. The other end of the outlet lower vertical pipe 16 is the outlet flange 8.

[0027] All of the above-mentioned horizontal elbows 3 and vertical elbows 4 are 3D elbows, which can effectively reduce the pipe resistance drop and reduce the number of elbows.

[0028] The outer jacket 2 is a two-stage heat exchange structure, that is, the outer jacket 2 is divided into two sections by the jacket flange 10. Each section of the outer jacket 2 is welded to the jacket flange 10 to form a closed hot water circulation space. Each section of the outer jacket 2 is provided with a hot water inlet 11 and a hot water outlet 12, thus forming two hot water inlets and two hot water outlets, which can better facilitate heat exchange. The medium inside the outer jacket 2 is hot water.

[0029] like Figure 3 As shown, baffles 13 are installed every 2 to 4 m between the outer jacket tube 2 and the square coil 1. One end of the baffle 13 is welded to the outer wall of the square coil 1, and the other end of the baffle 13 is left with a distance from the inner wall of the outer jacket tube 2. 3 to 4 baffles 13 are evenly arranged in each radial section. The baffles 13 can improve the fluid flow pattern, increase the heat transfer coefficient, and enhance the heat transfer effect.

[0030] The upper, middle, and lower square tubes each have a bracket 5 welded to both ends of the horizontal straight tube 14 on the same side along the length direction. The brackets 5 on the same side and at the same end are arranged in a straight line and rooted on the same support beam 9. The lower vertical tube 15 at the inlet has two brackets 5 welded to it. The two brackets 5 are arranged in a straight line and rooted on the same support beam 9. This arrangement of the shared support beam 9 reduces the space occupied by the support beam, thereby enhancing the space utilization rate.

[0031] This invention employs a spatial square structure, increasing the length of the lower coil in the converter within a limited three-dimensional space, thereby increasing the heat exchange area. Simultaneously, it reduces the number of elbows, thus decreasing fluid resistance drop and reducing blockage points. The square compensation structure effectively absorbs thermal stress, improving localized stress concentration, preventing failures caused by stress concentration, lowering the risk of coil defects, and extending the coil's service life. This invention also utilizes a two-stage heat exchange structure, with 3-4 baffles evenly distributed in each radial section, improving the fluid flow pattern, increasing the heat transfer coefficient, and enhancing the heat exchange effect.

Claims

1. A high-temperature exhaust gas pipeline assembly for a polycrystalline silicon reduction furnace, characterized in that: It includes a square coil (1) and an outer jacket (2). The square coil (1) is arranged on the skid top cover (6) inside the reduction furnace by a support beam (9). The shape of the outer jacket (2) is the same as that of the square coil (1), and the outer jacket (2) is fitted on the outer periphery of the square coil (1). The square coil (1) includes an upper square tube, a middle square tube and a lower square tube, which are arranged in a vertically corresponding manner.

2. The high-temperature exhaust gas pipeline assembly for a polycrystalline silicon reduction furnace according to claim 1, characterized in that: The upper square pipe includes four horizontal straight pipes (14) and three horizontal elbows (3). The four horizontal straight pipes (14) form a square structure through the three horizontal elbows (3). The free end of one of the horizontal straight pipes (14) is connected to one end of the inlet lower vertical pipe (15) through a vertical elbow (4). The other end of the inlet lower vertical pipe (15) is connected to one end of the outwardly extending inlet horizontal straight pipe (17) through a vertical elbow (4). The other end of the inlet horizontal straight pipe (17) is an inlet flange (7). The middle layer square tube includes four horizontal straight pipes (14) and three horizontal elbows (3). The four horizontal straight pipes (14) are arranged into a square structure by the three horizontal elbows (3). The free end of one of the horizontal straight pipes (14) is connected to the free end of the other horizontal straight pipe (14) of the upper layer square tube through a vertical elbow (4). The lower square pipe includes three horizontal straight pipes (14) and two horizontal elbows (3). The three horizontal straight pipes (14) are connected by the two horizontal elbows (3). The free end of one of the horizontal straight pipes (14) is connected to the free end of the other horizontal straight pipe (14) of the middle square pipe through a vertical elbow (4). The other horizontal straight pipe (14) is connected to one end of the outlet horizontal straight pipe (18) through a horizontal elbow (19). The other end of the outlet horizontal straight pipe (18) is connected to one end of the outlet lower vertical pipe (16) through a vertical elbow (4). The other end of the outlet lower vertical pipe (16) is the outlet flange (8).

3. The high-temperature exhaust gas pipeline assembly for a polycrystalline silicon reduction furnace according to claim 1 or 2, characterized in that: The outer jacket (2) is a two-section heat exchange structure. The outer jacket (2) is divided into two sections by a jacket flange (10). Each section of the outer jacket (2) is welded to the jacket flange (10) to form a closed hot water circulation space. Each section of the outer jacket (2) is provided with a hot water inlet (11) and a hot water outlet.

4. The high-temperature exhaust gas pipeline assembly for a polycrystalline silicon reduction furnace according to claim 1 or 2, characterized in that: A baffle (13) is installed every 2-4m between the outer sleeve (2) and the square coil (1). One end of the baffle (13) is welded to the outer wall of the square coil (1), and the other end of the baffle (13) is left with a distance from the inner wall of the outer sleeve (2).

5. The high-temperature exhaust gas pipeline assembly for a polycrystalline silicon reduction furnace according to claim 4, characterized in that: Each radial section of the square coil (1) is uniformly provided with 3 to 4 baffles (13).

6. The high-temperature exhaust gas pipeline assembly for a polycrystalline silicon reduction furnace according to claim 2, characterized in that: The upper, middle and lower square tubes are each welded with a bracket (5) at both ends of the horizontal straight tube (14) on the same side of the length direction. The brackets (5) on the same side and at the same end are arranged in a straight line and rooted on the same support beam (9).

7. The high-temperature exhaust gas pipeline assembly for a polycrystalline silicon reduction furnace according to claim 2, characterized in that: The lower vertical pipe (15) of the inlet has two supports (5) welded on the top and bottom. The two supports (5) are arranged in a straight line and rooted on the same support beam (9).

8. The high-temperature exhaust gas pipeline assembly for a polycrystalline silicon reduction furnace according to claim 1 or 2, characterized in that: The outer sleeve (2) is 2 inches larger in diameter than the square coil (1).

9. The high-temperature exhaust gas pipeline assembly for a polycrystalline silicon reduction furnace according to claim 2, characterized in that: Both the horizontal elbow (3) and the vertical elbow (4) are 3D elbows.

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