Tail gas pipe structure for reduction furnace

Abstract

The utility model provides a tail gas pipe structure for a reduction furnace, which relates to the technical field of tail gas treatment of the reduction furnace and comprises a first tail gas pipe, a second tail gas pipe, a first tail gas pipe and a second tail gas pipe, the second tail gas pipes are symmetrically arranged along the first tail gas pipe, and each second tail gas pipe is obliquely arranged on the first tail gas pipe; the first jacketed pipes are arranged on the outer walls of the second tail gas pipes in a sleeving mode, each first jacketed pipe is provided with a liquid inlet and a liquid outlet, the liquid inlets and the liquid outlets are distributed in the two sides of the first jacketed pipes, the liquid inlets are located in the sides, with the relatively low height, of the second tail gas pipes, and the liquid outlets are located in the sides, with the relatively low height, of the second tail gas pipes. The liquid outlet is located in the side, with the relatively high height, of the second tail gas pipe. According to the utility model, the scaling rate of amorphous silicon in the tail gas of the reduction furnace can be reduced while the contact time of a worker and the tail gas of the reduction furnace is reduced, so that the heat exchange efficiency of a double-pipe heat exchanger on the tail gas pipe is prevented from being influenced, and the yield of polycrystalline silicon is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of tail gas treatment of a reduction furnace, in particular to a tail gas pipe structure used in a reduction furnace. Background Art

[0002] During the production of polysilicon, the tail gas from the reduction furnace (temperature of about 500°C) needs to enter the shell and tube heat exchanger from the tail gas pipe of the reduction furnace to cool to about 200°C, and then enter the tail gas main pipe and be sent to the recovery section. Due to the continuous production of polycrystalline, the tail gas produced will contain amorphous silicon produced by the reduction furnace during the production process. This part of amorphous silicon will remain on the inner surface of the tail pipe, resulting in poor heat exchange effect of the shell and tube heat exchanger on the tail pipe. It is necessary to clean the inside of the tail pipe from time to time to clean up the amorphous silicon attached to the inner surface of the tail pipe to avoid blockage and affect production operations. In addition, since the tail gas pipe is an "S"-shaped pipe, that is, a coiled pipe with many bends, it is more difficult to clean the amorphous silicon that has scaled in the tail gas pipe, and it cannot be cleaned directly. Over time, the scaling of amorphous silicon in the tail gas pipe will become more serious, resulting in a decrease in the heat transfer efficiency of the shell and tube heat exchanger on the tail gas pipe, thereby making the temperature of the tail gas sent to the recovery section higher and higher, seriously affecting the production of polysilicon, and when cleaning the amorphous silicon that has scaled in the tail gas pipe of the reduction furnace, the tail gas of the reduction furnace will also cause certain harm to the human body. Utility Model Content

[0003] In order to solve the problem that amorphous silicon in the exhaust gas of a reduction furnace is easily scaled in the exhaust pipe, which leads to a decrease in the heat exchange efficiency of the exhaust gas, affects the output of polysilicon and requires frequent cleaning by staff, the utility model provides a tail gas pipe structure for a reduction furnace, which can reduce the contact time between the staff and the exhaust gas of the reduction furnace while reducing the scaling rate of amorphous silicon in the exhaust gas of the reduction furnace, thereby avoiding affecting the heat exchange efficiency of the sleeve heat exchanger on the tail gas pipe and improving the output of polysilicon.

[0004] The technical solution adopted by the utility model is:

[0005] Provided is a tail gas pipe structure for a reduction furnace, comprising:

[0006] A first tail gas pipe, the first tail gas pipe is a curved pipe, and both ends of the first tail gas pipe are respectively connected to the second tail gas pipe; a second tail gas pipe, the second tail gas pipe is symmetrically arranged along the cross-section of the middle part of the first tail gas pipe, and each second tail gas pipe is inclinedly arranged on the first tail gas pipe; a first jacketed tube, the first jacketed tube is sleeved on the outer wall of each second tail gas pipe, and each first jacketed tube is provided with a liquid inlet and a liquid outlet, and the liquid inlet and the liquid outlet are distributed on both sides of the first jacketed tube, the liquid inlet is located on a side of the second tail gas pipe with a relatively low height, and the liquid outlet is located on a side of the second tail gas pipe with a relatively high height.

[0007] In some embodiments of the present invention, the wall thickness of the first exhaust pipe is 11 mm-14.2 mm.

[0008] In some embodiments of the present invention, the first tail gas pipe is a 180° elbow.

[0009] In some embodiments of the present invention, the slope between each second tailpipe and the first tailpipe is 10‰.

[0010] In some embodiments of the present invention, there are multiple first tailpipes and multiple second tailpipes, and the number of first tailpipes is one less than the number of second tailpipes. Each first tailpipe is arranged between two adjacent second tailpipes.

[0011] In some embodiments of the present invention, a first connecting pipe is provided between the liquid inlet and the liquid outlet between adjacent first jacket tubes.

[0012] In some embodiments of the utility model, each first exhaust pipe is provided with a second jacket tube, each second jacket tube is provided with a second connecting tube communicating with one of the adjacent first jacket tubes, and adjacent second jacket tubes are provided with a third connecting tube communicating with each other.

[0013] In some embodiments of the present invention, the first tail gas pipe and the second tail gas pipe are integrally formed structures, and both are stainless steel pipes.

[0014] The beneficial effects of the utility model are:

[0015] One end of one of the second tail gas pipes is connected to the exhaust port of the reduction furnace for conveying the tail gas of the reduction furnace, and one end of the other second tail gas pipe conveys the tail gas to the recovery section. During the conveying process of the tail gas of the reduction furnace, the tail gas enters the first tail gas pipe through one of the second tail gas pipes. Since the tail gas contains a large amount of amorphous silicon, the amorphous silicon will accumulate inside the first tail gas pipe. By tilting the first tail gas pipe at a certain angle on the second tail gas pipe and connecting them, the amorphous silicon accumulated on the inner wall of the first tail gas pipe can be rolled toward the side of the first tail gas pipe with a relatively low height, thereby avoiding the amorphous silicon in the tail gas from accumulating on the inner wall of the first tail gas pipe, causing the first jacket pipe to reduce the heat exchange efficiency of the tail gas in the first tail gas pipe, thereby affecting the production efficiency of polysilicon. In addition, it can also reduce the number of times the staff cleans the first tail gas pipe and the second tail gas pipe, avoiding frequent contact with the tail gas and causing physical effects on the staff. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 Schematic diagram of the tail gas pipe structure for the reduction furnace Figure 1 ;

[0018] Figure 2 Schematic diagram of the tail gas pipe structure for the reduction furnace Figure 2 ;

[0019] Figure 3 Schematic diagram of the tail gas pipe structure for the reduction furnace Figure 3 ;

[0020] Figure 4 It is a schematic diagram of the structure of the connection between the first tailpipe and the second tailpipe.

[0021] Reference numerals:

[0022] 1-first tail gas pipe, 2-second tail gas pipe, 3-first jacket pipe, 4-second jacket pipe, 5-liquid inlet, 6-liquid outlet, 7-first connecting pipe, 8-second connecting pipe, 9-third connecting pipe, 10-connecting flange. DETAILED DESCRIPTION

[0023] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0024] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention.

[0025] The embodiments of the utility model are described in detail below with reference to the accompanying drawings.

[0026] Example

[0027] like Figure 1 As shown, this embodiment provides a tail gas pipe structure for a reduction furnace, comprising:

[0028] A first tailpipe 1, which is a curved pipe, and both ends of the first tailpipe 1 are respectively connected to a second tailpipe 2;

[0029] A second tailpipe 2, the second tailpipe 2 is symmetrically arranged along the cross section of the middle part of the first tailpipe 1, and each second tailpipe 2 is obliquely arranged on the first tailpipe 1;

[0030] The first jacket tube 3 is sleeved on the outer wall of each second tail gas pipe 2. Each first jacket tube 3 is provided with a liquid inlet 5 and a liquid outlet 6. The liquid inlet 5 and the liquid outlet 6 are distributed on both sides of the first jacket tube 3. The liquid inlet 5 is located on the side of the second tail gas pipe 2 with a relatively low height, and the liquid outlet 6 is located on the side of the second tail gas pipe 2 with a relatively high height.

[0031] The first tail gas pipe 1 is a curved pipe, and the inner diameter of the cross section along the middle part of the first tail gas pipe 1 is symmetrical with the axis of symmetry. Two second tail gas pipes 2 are connected at both ends of the first tail gas pipe 1, and the free end of one of the second tail gas pipes 2 is connected to the exhaust port of the reduction furnace, and the free end of the other second tail gas pipe 2 transports the tail gas to the recovery section for corresponding treatment, and the two second tail gas pipes 2 are also symmetrically arranged with the inner diameter of the cross section along the middle part of the first tail gas pipe 1 as the axis of symmetry. The second tail gas pipe 2 is a straight pipe, which is used to transport the tail gas discharged from the exhaust port of the reduction furnace. During the transportation process, amorphous silicon in the tail gas will scale on the inner wall of the second tail gas pipe 2. The first jacketed tube 3 is a piping system consisting of an inner tube and an outer tube, wherein the inner tube is sleeved on the outer wall of the second tail gas pipe 2, and the outer tube is fed with cooling water through the liquid inlet 5 and the liquid outlet 6. When in use, the inner tube performs heat exchange operation with the second tail gas pipe 2 that fits thereto, and the heat is transferred to the cooling water in the appearance, and the cooling water takes away the heat, thereby completing the heat exchange treatment of the tail gas in the tail gas pipe. In addition, since the second tail gas pipe 2 is obliquely arranged at both ends of the first tail gas pipe 1, and the cooling water in the first jacketed tube 3 needs to flow from low to high, therefore, the liquid inlet 5 on the first jacketed tube 3 is opened on the side of the second tail gas pipe 2 with a relatively low height, and the liquid outlet 6 is opened on the side of the second tail gas pipe 2 with a relatively high height, so as to better realize the heat exchange treatment of the tail gas in the tail gas pipe.

[0032] When in use, firstly, cooling water is passed into the first jacket tube 3, so that the second tail gas pipe 2 is in a state of lower temperature in advance, and then, the tail gas generated in the reduction furnace is discharged into the second tail gas pipe 2 through its own exhaust port, and when the tail gas passes through the second tail gas pipe 2 wrapped by the first jacket tube 3, its own heat will be transferred through the tube wall of the second tail gas pipe 2, and the transferred heat will be absorbed and taken away by the cooling water in the first jacket tube 3, so as to realize the heat exchange treatment of the tail gas. During the heat exchange treatment process, the tail gas generated in the reduction furnace contains a lot of amorphous silicon, and this part of amorphous silicon will scale on the inner wall of the second tail gas pipe 2, and the second tail gas pipe 2 is tilted on the first tail gas pipe 1, so that the amorphous silicon in the tail gas can roll on the second tail gas pipe 2, and the amorphous silicon scale is avoided on the inner wall of the second tail gas pipe 2, which causes the heat exchange efficiency of the first jacket tube 3 to be reduced, thereby reducing the number of times the staff cleans the first tail gas pipe 1 and the second tail gas pipe 2, and reducing the frequency of contact with the tail gas of the reduction furnace.

[0033] Furthermore, the wall thickness of the first tail gas pipe 1 is 11 mm-14.2 mm.

[0034] The wall thickness of the first tail pipe 1 connected between the two second tail pipes 2 is increased, and the thickness range of the thickened wall of the first tail pipe 1 is between 11mm and 14.2mm. In the present embodiment, the wall thickness adopted is a stainless steel pipe of DN100, sch160. The wall thickness of the first tail pipe 1 is increased. Since the second tail pipe 2 and the first tail pipe 1 are arranged at a certain inclination angle, the amorphous silicon in the second tail pipe 2 will enter the first tail pipe 1 during the flow and collide with the wall of the first tail pipe 1. Under a long-term collision, the wall of the first tail pipe 1 is easily damaged, thereby causing exhaust gas leakage and affecting the surrounding environment. Therefore, the wall of the first tail pipe 1 is thickened to avoid damage to the wall of the first tail pipe 1 after being repeatedly collided with by the amorphous silicon in the exhaust gas, thereby extending the service life of the first tail pipe 1.

[0035] Further, such as Figure 1-4 As shown, the first tail gas pipe 1 is a 180° elbow.

[0036] The first tail gas pipe 1 uses a 180° elbow, and the cross-sections of the openings at both ends of the elbow are on the same plane. In the present embodiment, the connection between the first tail gas pipe 1 and the second tail gas pipe 2 is sleeve welding. After the sleeve welding is adopted, the first tail gas pipe 1 can be disassembled regularly, and it is convenient to clean the residual scale in the first tail gas pipe 1 and the second tail gas pipe 2 after disassembly, and then the first tail gas pipe 1 and the second tail gas pipe 2 are connected again by sleeve welding. If the scale in the first tail gas pipe 1 is thick and difficult to clean, and the pipe wall is damaged and is not conducive to reuse, the first tail gas pipe 1 can be replaced, and then the first tail gas pipe 1 and the second tail gas pipe 2 are connected by sleeve welding. In this process, although the staff will regularly clean the scale of the first tail gas pipe 1 and the second tail gas pipe 2, due to the inclined setting of the second tail gas pipe 2, the scale in the first tail gas pipe 1 and the second tail gas pipe 2 will become less, which makes the staff need to regularly handle the tail gas pipe for a longer period of time, and reduces the number of contacts between the staff and the tail gas.

[0037] Further, such as Figure 1-3 As shown, the slope between each second tail gas pipe 2 and the first tail gas pipe 1 is 10‰.

[0038] The slope refers to the slope used to represent the slope, that is, the ratio of the vertical height h of the slope surface to the horizontal width l, that is, the tangent value of the slope angle. In this embodiment, the slope refers to the slope between the central axis of the second tail pipe 2 and the central axis of the first tail pipe 1 at the connection point, and the slope is 10‰, that is, 1%. The slope of 1% means that for every meter of horizontal distance, the vertical direction rises or falls by meters. Under this slope percentage value, the amorphous silicon contained in the tail gas entering the second tail pipe 2 will be difficult to accumulate on the inner wall of the second tail pipe 2. This part of the amorphous silicon will roll in the inclined direction of the second tail pipe 2 and enter the first tail pipe 1. Since the first tail pipe 1 is a 180° elbow, this part of the undeposited amorphous silicon can continue to roll and enter the next connected second tail pipe 2, avoiding most of the amorphous silicon in the tail gas in the second tail pipe 2 from scaling on the inner wall, causing the heat exchange of the tail gas to be blocked, affecting the production efficiency of polysilicon.

[0039] Further, such as Figure 1-3 As shown, there are multiple first tailpipes 1 and multiple second tailpipes 2 , and the number of first tailpipes 1 is one less than the number of second tailpipes 2 . Each first tailpipe 1 is arranged between two adjacent second tailpipes 2 .

[0040] Since the exhaust gas generated in the reduction furnace is large and continuous, the single first exhaust pipe 1 and the two second exhaust pipes 2 arranged at both ends of the first exhaust pipe 1 do not have obvious heat exchange effect on the exhaust gas. Therefore, it is necessary to set up multiple first exhaust pipes 1 and multiple second exhaust pipes 2, and one first exhaust pipe 1 is connected between every two second exhaust pipes 2, which means that the total number of second exhaust pipes 2 is one more than the total number of first exhaust pipes 1. In addition, after the multiple first exhaust pipes 1 and the multiple second exhaust pipes 2 are connected, the overall distribution is serpentine-like and connected end to end.

[0041] When in use, the exhaust gas passes through the connected second exhaust pipe 2 and the first exhaust pipe 1 in sequence, and the increased number of first exhaust pipes 1 and second exhaust pipes 2 prolongs the heat exchange time of the exhaust gas, and the exhaust gas in the exhaust pipe can greatly reduce its own temperature under the heat exchange effect of the first jacket tube 3, so that the temperature of the exhaust gas finally entering the recovery section is suitable for treatment.

[0042] Further, such as Figure 2 As shown, a first connecting pipe 7 is provided between the liquid inlet 5 and the liquid outlet 6 between adjacent first jacket tubes 3 .

[0043] The connecting pipe is arranged between the liquid inlet 5 and the liquid outlet 6, and is used to connect the first jacket tube 3 on each second tail gas pipe 2. In the present embodiment, the connecting line between the liquid inlet 5 of the previous first jacket tube 3 and the liquid outlet 6 of the next first jacket tube 3 is perpendicular to the horizontal plane, that is, the two correspond to each other, that is, the two are symmetrical about the cross-section of the middle part of the first tail gas pipe 1, which can save the material of the first connecting pipe 7 used, and enable the water in the previous first jacket tube 3 to quickly enter the next first jacket tube 3 to complete the heat exchange.

[0044] When in use, cooling water enters from the liquid inlet 5 of the first jacket tube 3, and after heat exchange treatment of the exhaust gas in the corresponding second exhaust pipe 2, it is discharged from the liquid outlet 6 at the other end of the first jacket tube 3, and enters the interior of the second first jacket tube 3 through the first connecting pipe 7, and then heat exchange treatment is performed on the exhaust gas in another second exhaust pipe 2, until it is discharged from the liquid outlet 6 on the last first jacket tube 3. The heat of the exhaust gas in all the second exhaust pipes 2 connected to the reduction furnace will be heat exchanged by the cooling water in the first jacket tube 3, and finally, the cooling water will flow back to the cooling water treatment equipment, lower its own temperature, and be used again for heat exchange of the exhaust gas in the second exhaust pipe 2.

[0045] Further, such as Figure 3 and Figure 4As shown, each first tail gas pipe 1 is sleeved with a second jacket pipe 4 , each second jacket pipe 4 is connected to one of the adjacent first jacket pipes 3 with a second connecting pipe 8 , and adjacent second jacket pipes 4 are connected with a third connecting pipe 9 .

[0046] The second jacket tube 4 is sleeved on the outer wall of the first tail gas pipe 1. The second jacket tube 4 can play a role of leak prevention. When the second tail gas pipe 2 is damaged by the collision of amorphous silicon in the tail gas, the jacket tube can temporarily play a protective role to prevent tail gas leakage. The second jacket tube 4 and one of the two adjacent first jacket tubes 3 are connected through the second connecting pipe 8. Specifically, according to the direction of the cooling water toward the liquid outlet 6, the purpose is to allow the cooling water to pass through the second jacket tube 4 to perform heat exchange treatment on the tail gas entering the first tail gas pipe 1. The third connecting pipe 9 is used to connect the adjacent second jacket tubes 4 in series between the two adjacent second jacket tubes 4 on the same side. In addition, the connection methods involved in the first connecting pipe 7, the second connecting pipe 8 and the third connecting pipe 9 in this embodiment are all flange connections, which are convenient for the staff to disassemble and install.

[0047] It is worth noting that in the present embodiment, the first tail gas pipe 1 and the second tail gas pipe 2 are connected by sleeve welding, that is, the first tail gas pipe 1 is welded around the second tail gas pipe 2, and the two ends of the second jacket pipe 4 and the two ends of the first jacket pipe 3 are connected by flanges but are not connected at both ends. The two are only connected by the second connecting pipe 8.

[0048] Furthermore, the first tail gas pipe 1 and the second tail gas pipe 2 are integrally formed structures, and both are stainless steel pipes.

[0049] When in use, the first tail gas pipe 1 and the second tail gas pipe 2, both of which are stainless steel, are made into an integrally formed structure. Since stainless steel has excellent corrosion resistance and high temperature resistance, it can meet the strict requirements of the polysilicon production process. In addition, stainless steel also has the characteristics of high strength and long life, which can ensure the safety and stability of the polysilicon production process, and the leakage rate is extremely low. Therefore, stainless steel pipes are selected for use as tail gas pipes.

[0050] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. In the absence of conflicts, the embodiments of the present application and the features in the embodiments may be arbitrarily combined with each other. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A tail gas pipe structure for a reduction furnace, characterized in that: include: A first tail gas pipe, the first tail gas pipe is a curved pipe, and the two ends of the first tail gas pipe are respectively connected to the second tail gas pipe; a second tail gas pipe, the second tail gas pipe is symmetrically arranged along the cross-section of the middle part of the first tail gas pipe, and each of the second tail gas pipes is inclinedly arranged on the first tail gas pipe; a first jacketed tube, the first jacketed tube is sleeved on the outer wall of each of the second tail gas pipes, and each of the first jacketed tubes is provided with a liquid inlet and a liquid outlet, the liquid inlet and the liquid outlet are distributed on both sides of the first jacketed tube, the liquid inlet is located on a side of the second tail gas pipe with a relatively lower height, and the liquid outlet is located on a side of the second tail pipe with a relatively higher height.

2. The tail gas pipe structure for a reduction furnace according to claim 1, characterized in that: The wall thickness of the first tail gas pipe is 11 mm-14.2 mm.

3. The tail gas pipe structure for a reduction furnace according to claim 2, characterized in that: The first tail gas pipe is a 180° elbow.

4. The tail gas pipe structure for a reduction furnace according to claim 3, characterized in that: The slope between each of the second tailpipes and the first tailpipe is 10‰.

5. The tail gas pipe structure for a reduction furnace according to claim 4, characterized in that: There are multiple first tailpipes and multiple second tailpipes, and the number of the first tailpipes is one less than the number of the second tailpipes. Each of the first tailpipes is arranged between two adjacent second tailpipes.

6. The tail gas pipe structure for a reduction furnace according to claim 1 or 5, characterized in that: A first connecting pipe is provided between the liquid inlet and the liquid outlet between adjacent first jacket pipes.

7. The tail gas pipe structure for a reduction furnace according to claim 6, characterized in that: Each of the first tail gas pipes is sleeved with a second jacket pipe, each of the second jacket pipes is connected to one of the adjacent first jacket pipes with a second connecting pipe, and adjacent second jacket pipes are connected with a third connecting pipe.

8. The tail gas pipe structure for a reduction furnace according to claim 7, characterized in that: The first tailpipe and the second tailpipe are integrally formed structures and are both stainless steel pipes.

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