Polycrystalline silicon cold hydrogenation system
By designing the level gauge to be installed horizontally and the flushing fluid to enter horizontally, the problem of level gauge blockage in the polycrystalline silicon cold hydrogenation system is solved, ensuring the accuracy and stability of the level gauge, extending its service life, and avoiding the risk of system shutdown.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- YUNNAN TONGWEI HIGH PURITY CRYSTALLINE SILICON CO LTD
- Filing Date
- 2025-05-23
- Publication Date
- 2026-04-28
AI Technical Summary
In existing polycrystalline silicon cold hydrogenation systems, vertical installation of the level gauge and flushing port can easily lead to port blockage, causing level gauge distortion and diaphragm damage, affecting the stable operation of the system and posing a safety risk.
Install the level gauge horizontally and allow the flushing fluid to enter the connecting pipe horizontally. Design a connecting pipe between the flushing branch pipe and the level gauge to avoid the flushing fluid directly impacting the diaphragm of the level gauge and to enhance the flushing force to remove deposits.
It effectively reduces blockage by high-boiling deposits, ensures accurate level measurement, extends the service life of the level gauge, avoids frequent unblocking operations, and prevents the risk of system shutdown.
Smart Images
Figure CN224172920U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of polycrystalline silicon production technology, and in particular to a polycrystalline silicon cold hydrogenation system. Background Technology
[0002] In the cold hydrogenation process, existing remote differential pressure level gauges are vertically installed on the external inlet of the scrubbing tower, with the flushing fluid (chlorosilane / silicon tetrachloride) vertically entering the level gauge and connecting to the equipment inlet pipe. For example... Figure 1 As shown, the outer side of the scrubbing tower 1 has a level gauge mounting position 100. The level gauge at the mounting position 100 is installed vertically, and the flushing branch pipe inlet is also set vertically. The inventors discovered that because the remote level gauge is installed vertically, the dead corner at the pipe inlet and the end of the remote level gauge is prone to become an area for the deposition of silica powder and metal chlorides (high boiling), increasing the risk of blockage. Furthermore, the vertically entering flushing fluid impacts both ends of the equipment pipe inlet and the remote level gauge simultaneously, dispersing the flushing pressure. When encountering high boiling deposits attached to the pipe inlet, it is often difficult to generate an effective flushing force, failing to completely flush away the high boiling deposits, which continuously accumulate at the pipe inlet, causing complete blockage of the equipment pipe inlet, resulting in level gauge distortion. The direct impact on the remote level gauge can also damage the level gauge diaphragm, shortening the service life of the level gauge. Often, it is necessary to stop feeding and then release the pressure to perform open-loop unblocking or pressurized unblocking to solve the problem of level gauge blockage. This poses a great safety risk to personnel. Pressure release and stopping feeding will disrupt the stable operation of the system, making it impossible for the slurry settling tank to receive the slag from the washing tower bottom normally, which in turn causes blockage of the slag discharge port of the washing tower bottom and the risk of system shutdown. Summary of the Invention
[0003] In view of the above situation and to overcome the defects of the prior art, the purpose of this utility model is to provide a polycrystalline silicon cold hydrogenation system, which solves the technical problem that the vertical installation of the level gauge and the flushing port in the existing polycrystalline silicon cold hydrogenation system easily leads to the blockage of the port.
[0004] To achieve the above objectives, this utility model provides the following technical solution:
[0005] A polycrystalline silicon cold hydrogenation system includes: a washing tower with a tray assembly inside; multiple horizontally arranged flushing branch pipes connected to a connecting pipe of the washing tower for conveying chlorosilane flushing liquid; the connecting pipes are located below the tray assembly and are equipped with a first control valve; a level gauge is horizontally installed on the connecting pipe between the first control valve and the flushing branch pipes; and a second control valve and a check valve are provided on the flushing branch pipes.
[0006] This invention, through horizontal installation of the level gauge, not only ensures accurate level measurement but also reduces the accumulation and blockage of high-boiling-point deposits, thus solving the problem of level gauge distortion. By designing and modifying the pipeline with the flushing fluid entering horizontally, the flushing fluid generates sufficient flushing force to effectively remove deposits. Furthermore, the horizontal entry of the flushing fluid avoids direct impact on the diaphragm of the remote level gauge, reducing the risk of diaphragm damage and extending the gauge's lifespan. Simultaneously, it improves the unblocking effect of the flushing fluid, thereby avoiding frequent unblocking operations and minimizing their impact on system stability. This also prevents blockage at the scrubbing tower's discharge port due to the slurry settling tank being unable to receive material, which could lead to system shutdown.
[0007] Optionally, the level gauge is a differential pressure level gauge.
[0008] Optionally, the tray set is a 12-layer tray.
[0009] Optionally, the polycrystalline silicon cold hydrogenation system further includes: a spray pipeline connected to the spray device inside the washing tower for supplying liquid chlorosilane to the washing tower; a main inlet pipe with its inlet end connected to the spray pipeline; and multiple flushing branch pipes with their inlet ends connected to the main inlet pipe and their outlet ends connected to corresponding connecting pipelines.
[0010] Optionally, the main inlet pipe is also connected to a first pipeline, one end of which is connected to the main inlet pipe and the other end is connected to the washing tower and located near the bottom tray.
[0011] Optionally, the polycrystalline silicon cold hydrogenation system further includes: a slag discharge pipeline, one end of which is connected to the slag discharge port at the bottom of the washing tower, and the other end of which is connected to the inlet of the mixing tank; and a purified gas delivery pipeline, one end of which is connected to the top outlet of the washing tower, and the other end of which is connected to the inlet of the condensation system.
[0012] Optionally, the lower end of the liquid inlet main pipe extends downward and is connected to multiple second pipes, the other end of which is connected to the slag discharge pipe.
[0013] Optionally, the polycrystalline silicon cold hydrogenation system includes a third pipeline, the inlet of which is connected to the vaporizer slag discharge port and the outlet of which is connected to the washing tower, for conveying the silicon tetrachloride slag liquid from the vaporizer to the washing tower.
[0014] Optionally, the polycrystalline silicon cold hydrogenation system also includes a fourth pipeline, the inlet of which is connected to the outlet of the fluidized bed reactor and the outlet of which is connected to the scrubbing tower for conveying reaction gas containing silicon powder, metal impurities and high-boiling substances.
[0015] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0016] This invention, through horizontal installation of the level gauge, not only ensures accurate level measurement but also reduces the accumulation and blockage of high-boiling-point deposits, thus solving the problem of level gauge distortion. By designing and modifying the pipeline with the flushing fluid entering horizontally, the flushing fluid generates sufficient flushing force to effectively remove deposits. Furthermore, the horizontal entry of the flushing fluid avoids direct impact on the diaphragm of the remote level gauge, reducing the risk of diaphragm damage and extending the gauge's lifespan. Simultaneously, it improves the unblocking effect of the flushing fluid, thereby avoiding frequent unblocking operations and minimizing their impact on system stability. This also prevents blockage at the scrubbing tower's discharge port due to the slurry settling tank being unable to receive material, which could lead to system shutdown. Attached Figure Description
[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 This is a schematic diagram of the existing technology.
[0019] Figure 2 This is a schematic diagram of an embodiment of the polycrystalline silicon cold hydrogenation system of this utility model.
[0020] Figure 3 This is a schematic diagram of the structure of Example 2.
[0021] Figure label:
[0022] 100. Level gauge installation position;
[0023] 1. Scrubber; 11. Tray assembly; 12. Connecting piping; 121. First control valve;
[0024] 2. Flushing branch pipe; 21. Second control valve; 22. Check valve;
[0025] 3. Level gauge;
[0026] 4. Spraying pipeline; 5. Liquid inlet main pipe; 6. First pipeline; 7. Slag discharge pipeline; 8. Purified gas delivery pipeline; 9. Second pipeline; 10. Third pipeline; 13. Fourth pipeline. Detailed Implementation
[0027] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the embodiments of this utility model application. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.
[0028] In the description of the embodiments of this utility model application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", "end", "side" etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, are only for the convenience of describing the embodiments of this utility model application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of this utility model application.
[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of this utility model application, "multiple" means two or more, unless otherwise explicitly specified.
[0030] In the embodiments of this utility model application, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this utility model application according to the specific circumstances.
[0031] In the embodiments of this utility model application, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0032] The following disclosure provides many different implementations or examples for carrying out different structures of the embodiments of this utility model application. To simplify the disclosure of the embodiments of this utility model application, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the embodiments of this utility model application. Furthermore, reference numerals and / or reference letters may be repeated in different examples of the embodiments of this utility model application; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or arrangements discussed.
[0033] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.
[0034] Cold hydrogenation process: In a fluidized bed reactor, silicon powder reacts with silicon tetrachloride and high-pressure hydrogen under the action of a catalyst to produce trichlorosilane in a closed-loop circulation process. This process will produce high-boiling substances that will affect the remote pressure gauge level gauge.
[0035] Existing level gauges are typically installed vertically at a 90° angle, and the flushing branch pipe inlet is also vertically set. High-boiling liquid repeatedly accumulates at the level gauge pressure measuring port, causing complete blockage of the equipment inlet and resulting in level gauge distortion. The vertically entering silicon tetrachloride flushing liquid simultaneously impacts both ends of the equipment inlet and the remote level gauge, causing some damage to the level gauge diaphragm and shortening the level gauge's service life. Often, it is necessary to stop the feeding and then release the pressure to perform open-loop unblocking operations or pressurized unblocking to solve the level gauge blockage problem, which poses a great safety risk to personnel. Pressure release and stopping the feeding will disrupt the stable operation of the system, making it impossible for the slurry settling tank to receive the slag from the washing tower bottom properly, which in turn causes blockage of the slag discharge port of the washing tower bottom and the risk of system shutdown.
[0036] Example 1
[0037] like Figure 2 As shown in the figure, this utility model application provides a polycrystalline silicon cold hydrogenation system to solve the above-mentioned problems. The polycrystalline silicon cold hydrogenation system includes a washing tower 1, multiple flushing branch pipes 2, and a level gauge 3.
[0038] The washing tower 1 is equipped with a tray assembly 11 inside. Multiple connecting pipes 12 are installed on the outer wall of the washing tower 1 below the tray assembly 11, and a first control valve 121 is installed on the connecting pipes 12.
[0039] Multiple flushing branch pipes 2 are horizontally arranged, with their outlet ends connected to the connecting pipe 12 of the washing tower 1. The flushing branch pipes 2 are used to transport chlorosilane flushing fluid. Each flushing branch pipe 2 is equipped with a second control valve 21 and a check valve 22. For example, the flushing branch pipes 2 are shown in the attached diagram. Figure 2 The four flushing branches shown.
[0040] The level gauge 3 is installed on the connecting pipe 12 between the first control valve 121 and the flushing branch pipe 2, and the level gauge 3.
[0041] Optionally, level gauge 3 is a differential pressure level gauge. Differential pressure level gauges are instruments that calculate the liquid level by measuring the pressure difference between two points, based on the principle of hydrostatics. Their accuracy is affected by the density of the medium and the unobstructedness of the pipeline.
[0042] Optionally, both the first control valve 121 and the second control valve 21 are ball valves.
[0043] Optionally, tray group 11 is a 12-layer tray.
[0044] As an implementation scenario, in this scenario, a settling zone is set between the bottom tray and the bottom of the tower, the inner diameter of the connecting pipe 12 is D, and the height of the pipe opening of the level gauge 3 from the settling zone of the washing tower is ≥2D.
[0045] The installation angle of the level gauge 3 in this invention has been adjusted from 90° (vertical) to 180° (horizontal), and the flushing branch pipe 2 enters horizontally at the end of the level gauge, eliminating dead zones in high-boiling material accumulation and reducing the risk of blockage. The horizontally entering flushing fluid avoids direct impact on the diaphragm of the level gauge, thus preventing damage and extending the service life of the level gauge. During use, parameters such as the flow rate, pressure, and flushing time of the flushing fluid can be adjusted to achieve the best unblocking effect.
[0046] Example 2
[0047] like Figure 3 As shown in the figure, this utility model application provides a polycrystalline silicon cold hydrogenation system. Based on embodiment 1, this embodiment of the polycrystalline silicon cold hydrogenation system further includes a spray pipeline 4 and a liquid inlet main pipe 5.
[0048] Spray pipe 4 connects the chlorosilane liquid source to the spray device inside the scrubbing tower 1, and is used to transport liquid chlorosilane to the scrubbing tower 1. Specifically, the inlet end of spray pipe 4 is connected to the chlorosilane liquid source, and the outlet end is connected to the scrubbing tower 1, with the outlet end located above the uppermost tray. The upper inlet end of the main inlet pipe 5 is connected to spray pipe 4, and the inlets of multiple flushing branch pipes 2 are all connected to the main inlet pipe 5.
[0049] In one embodiment, the liquid inlet main pipe 5 is also connected to a first pipeline 6, and the other outlet end of the first pipeline 6 is connected to the washing tower 1 and is located near the bottom tray.
[0050] In one embodiment, the lower end of the scrubbing tower 1 is connected to a slag discharge pipe 7, and the upper end is connected to a purified gas delivery pipe 8. The slag discharge pipe 7 discharges slag to the mixing tank. The purified gas delivery pipe 8 connects the top outlet of the scrubbing tower 1 to the inlet of the condensation system, and is used to deliver the mixed gas after spray scrubbing. Optionally, the lower end of the liquid inlet main pipe 5 extends towards the lower end of the scrubbing tower 1 and connects to multiple second pipes 9, with the other outlet end of the second pipe 9 connected to the slag discharge pipe 7. Both the first pipe 6 and the second pipe 9 are equipped with control valves and check valves.
[0051] In one embodiment, the polycrystalline silicon cold hydrogenation system includes a third pipeline 10, the inlet of which is connected to the vaporizer slag discharge port and the outlet of which is connected to a scrubbing tower 1, for conveying the silicon tetrachloride slag liquid from the vaporizer to the bottom of the scrubbing tower 1 to dilute the liquid in the bottom of the tower. The outlet of the third pipeline 10 is located near the bottom tray, that is, multiple flushing branch pipes 2 are located below the third pipeline.
[0052] In one embodiment, a fourth pipeline 13 is also included, located below the third pipeline 10. Its inlet end is connected to the outlet of the fluidized bed reactor, and its outlet end is connected to the inlet of the scrubbing tower 1, for conveying a reaction gas mixture containing silicon powder, metal impurities, and high-boiling substances. As one implementation scenario, in this scenario, four flushing branch pipes 2 are used, arranged in pairs on both sides of the fourth pipeline 13; that is, there are two flushing branch pipes above and two below the fourth pipeline 13.
[0053] The main purpose of this system is to process silicon tetrachloride, a byproduct of reduction. Using reduction byproduct hydrogen, synthesis byproduct hydrogen, and metallurgical-grade silicon powder as raw materials, the system reacts with silicon powder in a fluidized bed reactor at 500–560°C and 2.0–3.0 MPa. After the reaction, the reactants exchange heat with the inlet gas in a heat recovery heat exchanger. The reactants then enter a scrubbing tower to remove residual silicon powder and high-boiling-point gases. After multi-stage condensation, a crude product is obtained, containing approximately 28% trichlorosilane (by volume). The non-condensable gas (mainly hydrogen) is pressurized by a circulating hydrogen compressor and reintroduced into the system as a raw material. Liquid chlorosilane is sent to the tank area.
[0054] The reaction gas entering the scrubbing tower contains residual silicon powder, metallic impurities (iron, aluminum, calcium), and high-boiling-point substances. After being sprayed with chlorosilane liquid, these substances accumulate in the bottom liquid of the tower. The bottom liquid is diluted by periodically removing slag. However, when the concentration of impurities and high-boiling-point substances is too high, it is very easy to clog the remote level gauge, causing the remote level gauge to malfunction and fail to accurately display the level of the scrubbing tower.
[0055] This invention features a horizontally positioned flushing branch pipe and level gauge, which reduces the deposition of silica powder and metal chlorides at the pipe inlet, lowering the probability of blockage. The horizontally entering flushing fluid flows along the inner wall of the pipe, generating greater flushing force and effectively removing high-boiling deposits adhering to the equipment inlet. Simultaneously, the horizontal flushing method avoids direct impact of the flushing fluid on the level gauge diaphragm, thereby reducing damage to the diaphragm and extending the level gauge's service life.
[0056] Any aspects not described in detail in this embodiment are techniques known in the art.
[0057] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in this utility model, and these should all be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.
Claims
1. A polycrystalline silicon cold hydrogenation system, characterized in that, include: The scrubbing tower has an internal tray assembly. Multiple horizontally arranged flushing branch pipes are connected to the connecting pipes of the washing tower for conveying chlorosilane flushing liquid; The connecting pipeline is located below the tray assembly and is equipped with a first control valve; A level gauge is horizontally installed on the connecting pipe between the first control valve and the flushing branch pipe; The flushing branch pipe is equipped with a second control valve and a check valve.
2. The polycrystalline silicon cold hydrogenation system according to claim 1, characterized in that, The level gauge is a differential pressure level gauge.
3. The polycrystalline silicon cold hydrogenation system according to claim 1, characterized in that, The tray assembly consists of 12 trays.
4. The polycrystalline silicon cold hydrogenation system according to claim 1, characterized in that, The polycrystalline silicon cold hydrogenation system also includes: The spray pipeline is connected to the spray device inside the scrubbing tower and is used to deliver liquid chlorosilane to the scrubbing tower; The liquid inlet main pipe has its inlet end connected to the spray pipe; The inlet ends of the multiple flushing branch pipes are respectively connected to the main liquid inlet pipe, and the outlet ends are connected to the corresponding connecting pipes.
5. The polycrystalline silicon cold hydrogenation system according to claim 4, characterized in that, The main inlet pipe is also connected to a first pipeline, one end of which is connected to the main inlet pipe and the other end is connected to the washing tower and is located near the bottom tray.
6. The polycrystalline silicon cold hydrogenation system according to claim 4, characterized in that, The polycrystalline silicon cold hydrogenation system also includes: The slag discharge pipeline is connected at one end to the slag discharge port at the bottom of the washing tower and at the other end to the inlet of the mixing tank. The purified gas delivery pipeline is connected at one end to the top outlet of the scrubbing tower and at the other end to the inlet of the condensation system.
7. The polycrystalline silicon cold hydrogenation system according to claim 6, characterized in that, The lower end of the liquid inlet main extends downward and connects to multiple second pipelines, the other end of which is connected to the slag discharge pipeline.
8. The polycrystalline silicon cold hydrogenation system according to any one of claims 1-7, characterized in that, The polycrystalline silicon cold hydrogenation system includes a third pipeline, the inlet of which is connected to the vaporizer slag discharge port and the outlet of which is connected to the washing tower, for conveying the silicon tetrachloride slag liquid from the vaporizer to the washing tower.
9. The polycrystalline silicon cold hydrogenation system according to claim 8, characterized in that, The polycrystalline silicon cold hydrogenation system also includes a fourth pipeline, the inlet of which is connected to the outlet of the fluidized bed reactor and the outlet of which is connected to the scrubbing tower, for conveying the reaction gas to the scrubbing tower, the reaction gas containing silicon powder, metal impurities and high-boiling substances.
10. The polycrystalline silicon cold hydrogenation system according to claim 9, characterized in that, The third pipeline is located above the multiple flushing branch pipes; the fourth pipeline is located below the third pipeline, and has two flushing branch pipes above and below the fourth pipeline respectively.