Polycrystalline silicon high-boiling residue concentration system

Abstract

The utility model belongs to the technical field of high-boiling-point substance concentration, and provides a polycrystalline silicon high-boiling-point substance concentration system which comprises a high-boiling-point substance concentration tower, a tower kettle reboiler and a tower kettle buffer tank, the bottom of the high-boiling residue concentration tower is connected with a tower kettle buffer tank through an extraction pipeline; the bottom of the tower kettle reboiler is communicated with an extraction pipeline through a thermosiphon pipeline; and the upper part of the tower kettle reboiler is communicated with the high-boiling residue concentration tower through an upper pipeline. And the top of the tower kettle buffer tank is communicated with the middle part of the high-boiling residue concentration tower through a gas phase balance pipeline. According to the utility model, the thermosiphon pipeline of the tower kettle reboiler is arranged at the upper part of the extraction pipeline at the lowest point of the tower kettle of the high-boiling residue concentration tower, so that the problem that the tower kettle reboiler and the tower kettle pipeline are blocked when the high-boiling tower kettle is concentrated is solved. The concentrated high-boiling-point substances and the like enter a tower kettle buffer tank through an extraction pipeline, one part of the high-boiling-point substances in the tower kettle buffer tank are conveyed to the high-boiling-point cracking reaction kettle through a pump, and the other part of the high-boiling-point substances return to the high-boiling-point substance concentration tower kettle through a pump return pipeline, so that the liquid level of the high-boiling-point substance concentration tower kettle is maintained.

Description

Technical Field

[0001] This utility model belongs to the field of high boiling point concentration technology, specifically relating to a polycrystalline silicon high boiling point concentration system. Background Technology

[0002] In the polysilicon production process, the high-boiling-point substances produced by the cold hydrogenation unit mainly consist of silicon tetrachloride, trichlorosilane, metal chlorides, and hexachlorosilane. The current process involves concentrating the substances in a high-boiling-point distillation column, then condensing the vaporous chlorosilane at the top of the column and sending it to an upstream unit for recycling. The high-boiling-point substances at the bottom of the column (mainly hexachlorosilane) are pumped to a high-boiling-point reactor. In the reactor, HCl gas and a catalyst are introduced, causing a cracking reaction that produces vaporous chlorosilane, which enters the distillation column. After condensation at the top of the distillation column, the condensate (chlorosilane) is sent to the upstream unit for recycling. Unreacted high-boiling-point substances and metallic impurities in the reactor are discharged to a regeneration tank via pressure differential, and then discharged to a mobile tanker for external treatment.

[0003] Existing high-boiling-point concentration towers, such as Figure 1 As shown, the bottom of the high-boiling-point concentration tower 1 is connected to the reboiler 2 via pipeline 6. In the reboiler 2, chlorosilanes vaporize and enter the high-boiling-point concentration tower 1 for distillation to separate monomeric chlorosilanes such as trichlorosilane and silicon tetrachloride, thus achieving the purpose of high-boiling-point concentration. Chlorosilanes in the bottom of the high-boiling-point concentration tower 1 are siphoned to the reboiler 2 via thermosiphon pipeline 6 for heating and vaporization. Chlorosilanes at the bottom of the reboiler 2 can also be returned to the bottom of the high-boiling-point concentration tower 1 via thermosiphon pipeline 6, and then via pipeline 7 to the feed pump 4 of the high-boiling-point concentration tower 1. The feed pump 4 returns a portion of the chlorosilanes to the high-boiling-point concentration tower 1 via pipeline 8, and another portion is transported to the high-boiling-point feed tank 3 via pipeline 9. Valves are installed on pipelines 8 and 9 to regulate the flow rate.

[0004] The high-boiling-point substances in the high-boiling-point feed tank 3 are sent to the original high-boiling-point feed pump 5 via pipeline 4 10. Part of them are returned to the high-boiling-point feed tank 3 via pipeline 5 11, and part of them are transported to the high-boiling-point reactor via pipeline 6 12 for high-boiling-point cracking reaction. There are valves on pipeline 5 11 and pipeline 6 12 to regulate the flow rate.

[0005] The feed pump 4 from the bottom of the high boiling point concentration tower 1 to the reboiler 2 and from the bottom of the high boiling point concentration tower 1 to the reboiler is transported through pipeline 6 and pipeline 7, respectively. The thermosiphon pipeline 6 at the bottom of the reboiler 2 is prone to the polymerization and deposition of silicon powder and metal chlorides during long-term operation, which causes blockage of the thermosiphon pipeline 6 at the bottom of the reboiler 2 and the tube bundle of the reboiler 2.

[0006] The high-boiling-point concentrate from the bottom of the high-boiling-point enrichment tower 1 is transported to the high-boiling-point feed tank 3 via pipeline 2 7, enrichment tower bottom feed pump 4, and pipeline 3 9. In the feed tank 3, the high-boiling-point concentrate, along with the silicon powder and metal chlorides therein, cools naturally, causing the metal chlorides to precipitate. This precipitation leads to scaling in the high-boiling-point feed tank 3, which causes blockage in the bottom outlet pipeline 4 10 of the high-boiling-point feed tank 3. Consequently, the original high-boiling-point feed pump 5 cannot operate, and the high-boiling-point unit is shut down for maintenance.

[0007] However, existing technologies have the following problems:

[0008] ① When high-boiling-point substances are concentrated in high-boiling-point substance concentration tower 1, the inlet of the feed pump 4 at the bottom of the tower is lower than the horizontal position of the thermosiphon pipe 6 at the bottom of the reboiler 2, which prevents the substances from flowing out. This causes the metal chlorides concentrated in the high-boiling-point substances to form scale inside the tubes of the reboiler 2, affecting the heat exchange efficiency of the reboiler 2. At the same time, the thermosiphon pipe 6 at the bottom of the reboiler 2 is prone to blockage due to metal chloride scale, requiring shutdown for maintenance.

[0009] ② After the high-boiling-point substance is concentrated, it is transported to the high-boiling-point feed tank 3 through the bottom feed pump 4. The metal chlorides in the high-boiling-point substance precipitate in the high-boiling-point feed tank 3 due to the decrease in temperature. They are prone to depositing in the inlet pipe 10 of the original high-boiling-point feed pump 5, the filter of the high-boiling-point feed pump (not shown), and the bottom of the high-boiling-point feed tank 3, which can cause blockages. It is necessary to shut down the system for cleaning, which reduces the system operation cycle and increases maintenance costs. Utility Model Content

[0010] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a polycrystalline silicon high-boiling-point concentration system, which solves the problem of blockage of the reboiler and pipelines in the high-boiling-point column during concentration.

[0011] To achieve the above objectives / to solve the above technical problems, this utility model adopts the following technical solution:

[0012] This utility model provides a polycrystalline silicon high-boiling-point concentration system, including a high-boiling-point concentration tower, a reboiler, and a buffer tank.

[0013] The bottom of the high-boiling-point concentration tower is connected to the tower bottom buffer tank via a collection pipeline;

[0014] The bottom of the reboiler in the tower is connected to the extraction pipeline via a thermosiphon pipeline.

[0015] The upper part of the reboiler is connected to the high-boiling-point concentration tower via an upper pipeline.

[0016] The above setup achieves the following effect: by installing a thermosiphon pipeline for the reboiler on the outlet pipeline at the lowest point of the high-boiling-point concentration tower, the problem of blockage of the reboiler and pipeline during high-boiling-point concentration is solved.

[0017] Further configuration: The top of the column bottom buffer tank is connected to the middle of the high-boiling-point concentration column via a gas phase balance pipeline.

[0018] The above setup achieves the following effect: at the bottom of the high-boiling-point concentration tower, the concentrated high-boiling-point substances, along with metal chlorides and silicon powder within them, enter the tower bottom buffer tank through the outflow pipeline. A portion of the high-boiling-point substances in the tower bottom buffer tank is returned to the tower bottom of the high-boiling-point concentration tower through the gas phase balance pipeline, thus maintaining the tower bottom liquid level of the high-boiling-point concentration tower.

[0019] Furthermore, the height of the connection point between the gas phase balance pipeline and the high-boiling-point concentration tower is higher than the liquid level height inside the high-boiling-point concentration tower.

[0020] The above setup achieves the following effect: the height of the pipeline from the top of the buffer tank to the inlet of the high-boiling-point concentration tower is higher than the liquid level inside the high-boiling-point concentration tower, so as to reserve gas phase space in the buffer tank and ensure the operability of the liquid level in the buffer tank.

[0021] The upper part of the bottom buffer tank is connected to the high-boiling-point concentration tower via a pipeline, forming a gas phase balance pipeline for the bottom buffer tank. This maintains the pressure balance of the bottom buffer tank and ensures that the concentrated high-boiling-point substances in the bottom of the high-boiling-point concentration tower can be transported to the bottom buffer tank through the outflow pipeline from the bottom of the high-boiling-point concentration tower.

[0022] Furthermore, the height of the connection point between the gas phase balance pipeline and the high-boiling-point concentration tower is higher than the height of the reboiler liquid level.

[0023] Furthermore, the height of the connection point between the gas phase balance pipeline and the high-boiling-point concentration tower is higher than the height of the connection point between the upper pipeline of the reboiler and the high-boiling-point concentration tower.

[0024] The above setup achieves the following effect: the height of the pipeline from the top of the reboiler to the inlet of the high-boiling-point concentration tower is higher than the height of the pipeline from the top of the reboiler to the inlet of the high-boiling-point concentration tower, so as to reserve gas phase space in the reboiler and ensure the operability of the liquid level in the reboiler.

[0025] Furthermore, the system also includes a high-boiling-point feed pump;

[0026] The bottom of the tower bottom buffer tank is connected to the input end of the high-boiling feed pump via a feed pipeline;

[0027] The output end of the high-boiling-point feed pump is connected to the high-boiling-point concentration tower via a reflux pipeline.

[0028] The above setup achieves the following effects: This utility model eliminates the bottom feed pump, reducing one pump, and realizes the functions of bottom feed and high-boiling feed pump through the high-boiling feed pump, thereby reducing equipment investment and power consumption.

[0029] Furthermore, the system also includes a high-boiling reactor;

[0030] The high-boiling reactor is connected to the reflux pipeline via a reaction pipeline.

[0031] The above setup achieves the following effects: At the bottom of the high-boiling-point concentration tower, the concentrated high-boiling-point substances, along with metal chlorides and silicon powder within them, enter the tower bottom buffer tank through the outlet pipeline. The high-boiling-point substances in the buffer tank are then transported externally through the feed pipeline and the high-boiling-point feed pump. A portion is transported to the reactor for cracking via the feed pipeline, while the remainder is returned to the high-boiling-point concentration tower bottom through the reflux pipeline to maintain the tower bottom liquid level. At the bottom of the high-boiling-point concentration tower, the high-boiling-point substances enter the reboiler through a thermosiphon pipeline. After vaporization, they enter the high-boiling-point concentration tower through the upper pipeline of the reboiler.

[0032] Furthermore, the high-boiling-point concentration tower is also connected to a high-boiling-point pipeline for adding or supplementing low-concentration high-boiling-point substances into the high-boiling-point concentration tower.

[0033] Furthermore, the system also includes a tower top condenser;

[0034] The top of the high-boiling-point concentration tower is connected to the inlet of the top condenser via a top pipeline;

[0035] The outlet of the top condenser is connected to the upper part of the high-boiling-point concentration tower via a condensation pipe.

[0036] Furthermore, the condenser pipe is also connected to an output pipe.

[0037] The above setup achieves the following effects: high-boiling-point substances enter the high-boiling-point concentration tower through the high-boiling-point substance pipeline; monomeric chlorosilanes such as trichlorosilane and silicon tetrachloride in the high-boiling-point substances are condensed in the top condenser of the high-boiling-point concentration tower through the top pipeline; some monomeric chlorosilanes such as trichlorosilane and silicon tetrachloride are returned to the high-boiling-point concentration tower through the condensation pipeline; and some monomeric chlorosilanes such as trichlorosilane and silicon tetrachloride are collected through the output pipeline.

[0038] Furthermore, valves for controlling flow rates are installed on the extraction pipeline, gas phase balance pipeline, return pipeline, reaction pipeline, condensation pipeline, output pipeline, and high-boiling-point pipeline.

[0039] Compared with the prior art, the beneficial effects achieved by this utility model are as follows:

[0040] 1. A reboiler thermosiphon pipeline is installed on the outflow pipeline at the lowest point of the high boiling point concentration tower, which solves the problem of blockage of the reboiler and pipeline during the concentration of high boiling point products.

[0041] 2. The height of the pipeline from the top of the reboiler to the inlet of the high-boiling-point concentration tower is higher than the height of the pipeline from the top of the reboiler to the inlet of the high-boiling-point concentration tower, so as to reserve gas phase space in the reboiler and ensure the operability of the liquid level in the reboiler.

[0042] 3. The bottom feed pump was eliminated, reducing one pump. The bottom feed and high-boiling feed functions were achieved through a high-boiling feed pump, reducing equipment investment and power consumption. Attached Figure Description

[0043] Figure 1 This is a structural diagram of existing technology;

[0044] Figure 2 This is a schematic diagram of the structure of this utility model.

[0045] In the diagram: 1. High-boiling-point concentration tower; 2. Reboiler; 3. High-boiling-point feed tank; 4. Reboiler feed pump; 5. Original high-boiling-point feed pump; 6. Pipeline 1; 61. Thermosiphon pipeline; 7. Pipeline 2; 71. Outlet pipeline; 72. Outlet valve; 8. Pipeline 2; 9. Pipeline 3; 10. Pipeline 4; 11. Pipeline 5; 12. Pipeline 6; 13. Reboiler buffer tank; 14. High-boiling-point feed pump; 15. Feed pipeline; 16. Reaction pipeline; 17. Reflux pipeline; 18. Gas phase equilibrium pipeline; 19. Gas phase equilibrium valve; 20. High-boiling-point pipeline; 21. Upper pipeline; 22. Top condenser; 23. Top pipeline; 24. Condensation pipeline; 25. Output pipeline. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0047] In the description of this embodiment, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this embodiment. Example 1

[0048] This embodiment provides a polycrystalline silicon high-boiling-point concentration system, including a high-boiling-point concentration tower 1, a reboiler 2, and a buffer tank 13.

[0049] The bottom of the high-boiling-point concentration tower 1 is connected to the tower bottom buffer tank 13 via the outflow pipeline 71;

[0050] The bottom of the reboiler 2 is connected to the extraction pipeline 71 via a thermosiphon pipeline 61;

[0051] The upper part of the reboiler 2 is connected to the high-boiling-point concentration tower 1 via the upper pipeline 21.

[0052] Implementation principle: A thermosiphon pipe 61 for the reboiler 2 is installed on the collection pipe 71 at the lowest point of the high boiling point concentration tower 1, which solves the problem of blockage of the reboiler 2 and the reboiler pipe during the concentration of high boiling point. Example 2

[0053] Based on the same design principle as in Embodiment 1, this embodiment provides a polycrystalline silicon high-boiling-point concentration system, including a high-boiling-point concentration tower 1, a reboiler 2, and a buffer tank 13 connected together; both the high-boiling-point concentration tower 1 and the reboiler 2 can be existing products.

[0054] The bottom of the high-boiling-point concentration tower 1 is connected to the bottom buffer tank 13 via the outflow pipeline 71;

[0055] The bottom of the reboiler 2 is connected to the collection pipeline 71 via a thermosiphon pipeline 61;

[0056] The upper part of the reboiler 2 is connected to the high boiling point concentration tower 1 via the upper pipeline 21.

[0057] A thermosiphon pipe 61 for the reboiler 2 is installed on the collection pipe 71 at the lowest point of the high boiling point concentration tower 1, which solves the problem of blockage of the reboiler 2 and the reboiler pipe during the concentration of high boiling point.

[0058] Specifically, the top of the bottom buffer tank 13 is connected to the bottom of the high-boiling-point concentration tower 1 via a gas phase balance pipeline 18.

[0059] Preferably, the height of the connection point between the gas phase balance pipeline 18 and the high boiling point concentration tower 1 is higher than the liquid level height inside the high boiling point concentration tower 1.

[0060] Preferably, the top of the column bottom buffer tank 13 is connected to the lower part of the high boiling point concentration column 1 via a gas phase balance pipeline 18 and is located above the upper part of the column bottom reboiler 2, connected to the upper pipeline 21.

[0061] Specifically, the height of the connection point between the gas phase equilibrium pipeline 18 and the high boiling point enrichment tower 1 is higher than the height of the connection point between the upper pipeline 21 and the high boiling point enrichment tower 1.

[0062] Preferably, the system further includes a high-boiling-point feed pump 14; the bottom of the column bottom buffer tank is connected to the input end of the high-boiling-point feed pump 14 via a feed pipe 15; the output end of the high-boiling-point feed pump 14 is connected to the high-boiling-point concentration column 1 via a reflux pipe 17.

[0063] This invention eliminates the bottom feed pump 4, reducing the number of pumps by one. The functions of bottom feed and high boiling feed pump 14 are achieved through the high boiling feed pump 14, thereby reducing equipment investment and power consumption.

[0064] Preferably, the system also includes a high-boiling reactor; the high-boiling reactor is connected to a reflux pipeline 17 via a reaction pipeline 16.

[0065] Specifically, the high-boiling-point concentration tower 1 is also connected to a high-boiling-point pipeline 20, which is used to add high-boiling-point substances to the high-boiling-point concentration tower 1.

[0066] Preferably, the system further includes a top condenser 22; the top of the high-boiling-point concentration tower 1 is connected to the inlet of the top condenser 22 via a top pipe 23; the outlet of the top condenser 22 is connected to the upper part of the high-boiling-point concentration tower 1 via a condensation pipe 24.

[0067] Preferably, the condenser pipe 24 is also connected to the output pipe 25.

[0068] High-boiling-point substances enter the high-boiling-point concentration tower 1 through the high-boiling-point substance pipeline 20. Monomeric chlorosilanes such as trichlorosilane and silicon tetrachloride in the high-boiling-point substances are condensed at the top of the high-boiling-point concentration tower 1 through the top pipeline 23. Some of the monomeric chlorosilanes such as trichlorosilane and silicon tetrachloride are returned to the high-boiling-point concentration tower 1 through the condensation pipeline 24, and some of the monomeric chlorosilanes such as trichlorosilane and silicon tetrachloride are collected through the output pipeline 25.

[0069] Preferably, valves for controlling flow rate are installed on the extraction pipeline 71, the gas phase balance pipeline 18, the return pipeline 17, the reaction pipeline, the condensation pipeline 24, the output pipeline 25, and the high-boiling-point pipeline 20.

[0070] In practical use, high-boiling-point substances enter high-boiling-point concentration tower 1 through high-boiling-point substance pipeline 20 and valves on high-boiling-point substance pipeline 20. In high-boiling-point concentration tower 1, monomeric chlorosilanes such as trichlorosilane and silicon tetrachloride in the high-boiling-point substances are condensed through top pipeline 23 to top condenser 22 of high-boiling-point concentration tower 1. Some monomeric chlorosilanes such as trichlorosilane and silicon tetrachloride are returned to high-boiling-point concentration tower 1 through condensation pipeline 24, and some monomeric chlorosilanes such as trichlorosilane and silicon tetrachloride are collected through output pipeline 25.

[0071] At the bottom of the high-boiling-point concentration tower 1, the concentrated high-boiling-point substances, along with metal chlorides and silicon powder within them, enter the tower bottom buffer tank 13 through the outlet pipe 71 and outlet valve 72. The high-boiling-point substances in the tower bottom buffer tank 13 are then transported externally through the feed pipe 15 and high-boiling-point feed pump 14. A portion is transported to the high-boiling-point reactor for cracking reaction through the reaction pipe 16, while the remaining portion is returned to the tower bottom of the high-boiling-point concentration tower 1 through the reflux pipe 17 to maintain the liquid level in the tower bottom of the high-boiling-point concentration tower 1. At the bottom of the high-boiling-point concentration tower 1, the high-boiling-point substances enter the tower bottom reboiler 2 through the thermosiphon pipe 61. After vaporization, they enter the high-boiling-point concentration tower 1 through the upper pipe 21 of the tower bottom reboiler 2.

[0072] The upper part of the bottom buffer tank 13 is connected to the high boiling point concentration tower 1 through the gas phase balance pipeline 18 and the gas phase balance valve 19, forming the vapor phase balance pipeline of the bottom buffer tank 13. This maintains the pressure balance of the bottom buffer tank 13 and ensures that the concentrated high boiling point of the bottom buffer tank 13 can be transported to the bottom buffer tank 13 through the bottom outlet pipeline 71 of the high boiling point concentration tower 1 and the outlet valve 72 on the outlet pipeline 71.

[0073] The height of the gas phase balance pipeline 18 at the top of the column bottom buffer tank 13 to the inlet of the high boiling point concentration column 1 is higher than the height of the upper pipeline 21 of the column bottom reboiler 2 to the inlet of the high boiling point concentration column 1, and is at least higher than the liquid level of the column bottom of the high boiling point concentration column 1, so as to reserve gas phase space in the column bottom buffer tank 13 and ensure the operability of the liquid level in the column bottom buffer tank 13.

[0074] The high-boiling-point feed pump 14 regulates the reflux flow rate through the reflux pipeline 17 and the valve installed on the reflux pipeline 17, maintaining the temperature of the tower bottom buffer tank 13 at no less than 100°C, ensuring that the temperature of the concentrated high-boiling-point substance remains constant during the transportation process, and preventing the precipitation of metal chlorides in the concentrated high-boiling-point substance due to the decrease in temperature.

[0075] 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, and in the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0076] In this utility model, 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 connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0077] In this invention, 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 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 directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0078] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0079] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A polycrystalline silicon high-boiling-point concentration system, characterized in that, It includes a high-boiling-point concentration tower (1), a reboiler (2), and a buffer tank (13); The bottom of the high-boiling-point concentration tower (1) is connected to the bottom buffer tank (13) via a collection pipeline (71); The bottom of the reboiler (2) is connected to the extraction pipeline (71) via a thermosiphon pipeline (61); The upper part of the reboiler (2) is connected to the high-boiling-point concentration tower (1) via an upper pipeline (21).

2. The polycrystalline silicon high-boiling-point concentration system according to claim 1, characterized in that, The top of the tower bottom buffer tank (13) is connected to the high boiling point concentration tower (1) via a gas phase balance pipeline (18).

3. The polycrystalline silicon high-boiling-point concentration system according to claim 2, characterized in that, The height of the connection point between the gas phase balance pipeline (18) and the high boiling point concentration tower (1) is higher than the bottom liquid level in the high boiling point concentration tower (1).

4. The polycrystalline silicon high-boiling-point concentration system according to claim 2, characterized in that, The height of the connection point between the gas phase balance pipeline (18) and the high boiling point enrichment tower (1) is higher than the height of the connection point between the upper pipeline (21) and the high boiling point enrichment tower (1).

5. The polycrystalline silicon high-boiling-point concentration system according to claim 1, characterized in that, The system also includes a high-boiling feed pump (14); The bottom of the tower bottom buffer tank is connected to the input end of the high boiling feed pump (14) through the feed pipe (15); The output end of the high boiling feed pump (14) is connected to the high boiling point concentration tower (1) through the reflux pipeline (17).

6. The polycrystalline silicon high-boiling-point concentration system according to claim 5, characterized in that, The system also includes a high-boiling reactor; The high-boiling reactor is connected to the reflux pipeline (17) via the reaction pipeline (16).

7. The polycrystalline silicon high-boiling-point concentration system according to claim 1, characterized in that, The high-boiling-point concentration tower (1) is also connected to a high-boiling-point pipeline (20) for adding or supplementing low-concentration high-boiling-point substances into the high-boiling-point concentration tower (1).

8. The polycrystalline silicon high-boiling-point concentration system according to claim 1, characterized in that, The system also includes a tower top condenser (22); The top of the high-boiling-point concentration tower (1) is connected to the inlet of the top condenser (22) via a top pipe (23); The outlet of the top condenser (22) is connected to the upper part of the high boiling point concentration tower (1) via a condensation pipe (24).

9. The polycrystalline silicon high-boiling-point concentration system according to claim 8, characterized in that, The condenser pipe (24) is also connected to an output pipe (25).

10. The polycrystalline silicon high-boiling-point concentration system according to claim 1, characterized in that, The extraction pipeline (71) is equipped with a valve for controlling the flow rate.

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