Network heat exchange system in polycrystalline silicon production
By adding an intermediate heat exchanger to the network heat exchange system in polysilicon production, the ladder cooling system is optimized, and the material cooling capacity is used to solve the problem of high-grade refrigerant cost, and lower energy consumption and production costs are achieved.
Patent Information
- Application Number
- CN202422350257.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2025-08-05
- Estimated Expiration
- 2034-09-26
AI Technical Summary
The existing polysilicon production has high cost of using medium and high grade refrigerant, and the configuration requirements for deep refrigerant equipment are high, resulting in expensive operating costs.
An intermediate heat exchanger is added between the multi-stage coolers, and the cooling capacity stored in the deep-cooled material is optimized through the step-by-stage cooling system to reduce the use of high-grade refrigerant, and the material is heated up in the absorption device.
Reduce the use of refrigerant and heat medium, significantly reduce the production cost of the heat exchange system, and achieve improvements without replacing existing equipment.
Smart Images
Figure CN223191859U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of heat exchange systems in polysilicon production, and in particular relates to a network heat exchange system in polysilicon production. Background Art
[0002] In the production of polysilicon, the main process steps such as cold hydrogenation, distillation, recovery, and reduction all involve refrigerant cooling, and the commonly used refrigerants include circulating water, 7°C water, -10°C Freon, -40°C Freon, -70°C dichloromethane, etc. as the main refrigerant media. They can usually cool the material to 33°C to -70°C, and use pressure to condense the heavy components in the gas phase or the solid residue in the liquid phase, thereby achieving the effect of material separation and improving the purity of the material.
[0003] When the temperature of the material needs to be cooled to a lower temperature, such as -70℃, the usual implementation method is to cool the material step by step rather than directly using -70℃ refrigerant to cool it to the target temperature. This is mainly based on the following reasons: when the temperature difference is too large, there are higher requirements for the stress requirements of the equipment welding thread, the heat exchange area of the heat exchanger, and the load of the refrigerant; the higher the grade of the cryogenic refrigerant, the higher the preparation cost. If deep cooling is used directly, the configuration requirements for the cryogenic refrigerant equipment are extremely high, and the operating costs are also high. The cost involved in long-term operation is high.
[0004] Therefore, in the polysilicon production process, a stepped cooling method is usually adopted. For example, if you want to cool the material to -70°C, you usually first cool the material to 33°C with circulating water, then use a 7°C refrigerant to cool the material to 10°C, then use -10°C Freon to cool the material to -8°C, then use -40°C Freon to cool the material to -35°C, and finally use -70°C dichloromethane refrigerant to condense it to the target temperature. This stepped cooling method not only achieves the comprehensive utilization of refrigerants, but more importantly, effectively reduces operating costs, making it a core technology for enterprise operations.
[0005] After investigation, it was found that the higher the grade of the refrigerant, the higher the preparation cost. Taking our company as an example, the cost of refrigerants using circulating water, 7℃ cooling water, -10℃ Freon, -40℃ Freon, and -70℃ dichloromethane are 0.012, 0.025, 0.140, 0.359, and 0.526 yuan / kW respectively. Therefore, the industry generally adopts low-grade heat exchange to reduce production costs.
[0006] At the same time, the industry is still constantly exploring and optimizing existing technologies to achieve efficient use of energy and reduce production costs. Utility Model Content
[0007] Based on the above background, the inventors of the present utility model took into consideration that in the cold hydrogenation section and the tail gas treatment section of polysilicon production, it is generally necessary to cool the material first (generally filtering, separation and other operations are required after cooling) and then heat it up. The coldness in the cooled material can be reused to achieve the comprehensive utilization of refrigerant, save the use of high-quality refrigerant, and thus reduce production costs.
[0008] In order to achieve the above-mentioned purpose of the invention, the technical solution of the present utility model is as follows:
[0009] The network heat exchange system in polysilicon production includes an absorption device. The feed inlet end of the absorption device is connected to a multi-stage cooler in sequence. The temperature of the cooling medium in the previous stage of the multi-stage cooler is higher than the temperature of the cooling medium in the next stage. Intermediate heat exchangers are additionally provided between coolers of adjacent stages and between the highest stage cooler and the absorption device. All intermediate heat exchangers are connected in sequence through pipelines. The cooled material in the absorption device serves as the cooling medium of the intermediate heat exchanger. The temperature of the cooling medium in the intermediate heat exchanger of the previous stage is lower than the temperature of the cooling medium in the next stage.
[0010] Furthermore, a two-stage cooler is provided on the feed pipe connected to the feed port end of the absorption device, a first-stage intermediate heat exchanger is added between the highest-stage cooler and the absorption device, a second-stage intermediate heat exchanger is provided between the two-stage coolers, and the discharge port of the absorption device is connected to the medium inlet of the first-stage intermediate heat exchanger through a pipeline, and the medium outlet of the first-stage intermediate heat exchanger is connected to the medium inlet of the second-stage intermediate heat exchanger through a pipeline.
[0011] Furthermore, the highest-level cooler is a heat exchanger with a -70°C dichloromethane medium or a -40°C Freon medium.
[0012] Furthermore, a three-stage cooler is provided on the feed pipeline connected to the feed port end of the absorption device, and the three-stage coolers include, from high to low levels, a -70°C dichloromethane cooler, a -40°C Freon cooler and a -10°C Freon cooler; a first-stage intermediate heat exchanger, a second-stage intermediate heat exchanger and a third-stage intermediate heat exchanger are respectively provided between the third-stage cooler and the absorption device, between the second-stage cooler and the third-stage cooler, and between the first-stage cooler and the second-stage cooler, and the discharge port of the absorption device is connected to the medium inlet of the first-stage intermediate heat exchanger through a pipeline, the medium outlet of the first-stage intermediate heat exchanger is connected to the medium inlet of the second-stage intermediate heat exchanger through a pipeline, and the medium outlet of the second-stage intermediate heat exchanger is connected to the medium inlet of the third-stage intermediate heat exchanger through a pipeline.
[0013] Furthermore, a four-stage cooler is provided on the feed pipeline connected to the feed port end of the absorption device, and the four-stage coolers include, from high to low levels, a -70°C dichloromethane cooler, a -40°C Freon cooler, a -10°C Freon cooler and a 7°C water cooler; a first-stage intermediate heat exchanger, a second-stage intermediate heat exchanger, a third-stage intermediate heat exchanger and a fourth-stage intermediate heat exchanger are respectively provided between the fourth-stage cooler and the absorption device, between the third-stage cooler and the fourth-stage cooler, between the second-stage cooler and the third-stage cooler, and between the first-stage cooler and the second-stage cooler, the discharge port of the absorption device is connected to the medium inlet of the first-stage intermediate heat exchanger through a pipeline, the medium outlet of the first-stage intermediate heat exchanger is connected to the medium inlet of the second-stage intermediate heat exchanger through a pipeline, the medium outlet of the second-stage intermediate heat exchanger is connected to the medium inlet of the third-stage intermediate heat exchanger through a pipeline, and the medium outlet of the third-stage intermediate heat exchanger is connected to the medium inlet of the fourth-stage intermediate heat exchanger through a pipeline.
[0014] Furthermore, a five-stage cooler is provided on the feed pipeline connected to the feed port end of the absorption device, and the five-stage coolers include, from high to low, a -70°C dichloromethane cooler, a -40°C Freon cooler, a -10°C Freon cooler, a 7°C water cooler, and a 33°C water cooler; a first-stage intermediate heat exchanger, a second-stage intermediate heat exchanger, and a second-stage intermediate heat exchanger are respectively provided between the fifth-stage cooler and the absorption device, between the fourth-stage cooler and the fifth-stage cooler, between the third-stage cooler and the fourth-stage cooler, between the second-stage cooler and the third-stage cooler, and between the first-stage cooler and the second-stage cooler. The intermediate heat exchanger, the third-stage intermediate heat exchanger, the fourth-stage intermediate heat exchanger and the fifth-stage intermediate heat exchanger, the discharge port of the absorption device is connected to the medium inlet of the first-stage intermediate heat exchanger through a pipeline, the medium outlet of the first-stage intermediate heat exchanger is connected to the medium inlet of the second-stage intermediate heat exchanger through a pipeline, the medium outlet of the second-stage intermediate heat exchanger is connected to the medium inlet of the third-stage intermediate heat exchanger through a pipeline, the medium outlet of the third-stage intermediate heat exchanger is connected to the medium inlet of the fourth-stage intermediate heat exchanger through a pipeline, and the medium outlet of the fourth-stage intermediate heat exchanger is connected to the medium inlet of the fifth-stage intermediate heat exchanger through a pipeline.
[0015] Furthermore, a feed pipeline connected to the feed port end of the absorption device is provided with a first-stage cooler and a second-stage cooler, which respectively pass through 33°C cooling water and -40°C Freon medium; a first-stage intermediate heat exchanger is additionally provided between the second-stage cooler and the absorption device, and a second-stage intermediate heat exchanger is provided between the first-stage cooler and the second-stage cooler; the discharge port of the absorption device is connected to the medium inlet of the first-stage intermediate heat exchanger through a pipeline, and the medium outlet of the first-stage intermediate heat exchanger is connected to the medium inlet of the second-stage intermediate heat exchanger through a pipeline.
[0016] Beneficial effects of the utility model:
[0017] 1. This utility model proposes a novel network heat exchange system for polysilicon production. This system is particularly suitable for use in polysilicon production (e.g., in the cooling and hydrogenation process, the waste gas recovery process in the reduction process, etc.), where the material must be cooled, separated, and the heavy components removed before the light components are heated. The heated light components are then recycled back into the production system. This network heat exchange system is a further optimization of existing cascade heat exchange systems. By utilizing the large amount of cold stored in the cryogenically cooled material, intermediate heat exchangers are added between multiple coolers, allowing the cold-carrying material to serve as the cooling medium in these intermediate heat exchangers. Compared to conventional cascade cooling systems, this system reduces the use of raw refrigerant and heats the material after treatment in the absorption device (before it is sent to the next process stage). This reduces the amount of heat medium used for the heated material, thus also reducing the amount of heat medium used. This network heat exchange system for polysilicon production reduces power consumption during the preparation of the refrigerant and heat medium, significantly reducing the production cost of the heat exchange system.
[0018] 2. In the present invention, the network heat exchange system in polysilicon production is also applicable to working conditions where the material needs to be heated up first and then cooled down.
[0019] 3. In the present invention, the network heat exchange system in the production of polysilicon can be further modified on the existing step cooling system without replacing all the equipment, and can be used in a popularized manner. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a structural diagram of the present utility model.
[0021] Figure 2 This is a structural diagram of an implementation method in Example 3.
[0022] Figure 3 This is a structural diagram of an implementation method in Example 4.
[0023] Figure 4 It is a structural diagram of another implementation method of the network heat exchange system.
[0024] Among them, 1. Absorption device; 2. Feed pipeline; 3. Discharge pipeline; 4. First-stage cooler; 5. Second-stage cooler; 6. Third-stage cooler; 7. Fourth-stage cooler; 8. Fifth-stage cooler; 9. First-stage intermediate heat exchanger; 10. Second-stage intermediate heat exchanger; 11. Third-stage intermediate heat exchanger; 12. Fourth-stage intermediate heat exchanger; 13. Fifth-stage intermediate heat exchanger; 1.1. Feed port; 1.2. Discharge port. DETAILED DESCRIPTION
[0025] The present invention will be further described in detail below with reference to the embodiments, but the embodiments of the present invention are not limited thereto.
[0026] Example 1
[0027] This embodiment is the most basic implementation method, the network heat exchange system in polysilicon production, belongs to the technical field of heat exchange system in polysilicon production, and includes an absorption device 1, reference Figure 1 The feed port 1.1 of the absorption device 1 is connected to the first-stage cooler 4 and the second-stage cooler 5 in sequence. The temperature of the cooling medium passing through the first-stage cooler 4 is higher than the temperature of the cooling medium passing through the second-stage cooler 5. A first-stage intermediate heat exchanger 9 is added between the second-stage cooler 5 and the absorption device 1, and a second-stage intermediate heat exchanger 10 is added between the second-stage cooler 5 and the first-stage cooler 4. The two-stage intermediate heat exchangers are connected in sequence through pipelines. The material cooled in the absorption device 1 serves as the cooling medium of the intermediate heat exchanger. The temperature of the cooling medium in the first-stage intermediate heat exchanger 9 is lower than the temperature of the cooling medium in the second-stage intermediate heat exchanger 10, that is, the discharge port 1.2 of the absorption device 1 is connected to the medium inlet of the first-stage intermediate heat exchanger 9 through a pipeline, and the medium outlet of the first-stage intermediate heat exchanger 9 is connected to the medium inlet of the second-stage intermediate heat exchanger 10 through a pipeline.
[0028] In actual production, a multi-stage cooler can be designed based on on-site conditions or specific requirements to cool the material in stages. Intermediate heat exchangers are added between coolers at adjacent levels and between the highest-level cooler and the absorption device 1. All intermediate heat exchangers are connected in sequence through pipelines. The cooled material in the absorption device 1 serves as the cooling medium of the intermediate heat exchanger. The temperature of the cooling medium in the intermediate heat exchanger of the previous stage is lower than that of the cooling medium in the next stage.
[0029] Example 2
[0030] This embodiment is a further optimization of the embodiment 1, the difference being that the highest-level cooler is a heat exchanger with a -70°C dichloromethane medium or a -40°C Freon medium.
[0031] Example 3
[0032] Compared with Example 1-2, this embodiment is different in that:
[0033] refer to Figure 2In the network heat exchange system for polysilicon production, a three-stage cooler is provided on the feed pipeline 2 connected to the feed port 1.1 end of the absorption device 1. The three-stage coolers include, from high to low levels, a -70°C dichloromethane cooler, a -40°C Freon cooler and a -10°C Freon cooler; a first-stage intermediate heat exchanger 9, a second-stage intermediate heat exchanger 10 and a third-stage intermediate heat exchanger 11 are respectively provided between the third-stage cooler 6 and the absorption device 1, between the second-stage cooler 5 and the third-stage cooler 6, and between the first-stage cooler 4 and the second-stage cooler 5. The discharge port 1.2 of the absorption device 1 is connected to the medium inlet of the first-stage intermediate heat exchanger 9 through a pipeline, the medium outlet of the first-stage intermediate heat exchanger 9 is connected to the medium inlet of the second-stage intermediate heat exchanger 10 through a pipeline, and the medium outlet of the second-stage intermediate heat exchanger 10 is connected to the medium inlet of the third-stage intermediate heat exchanger 11 through a pipeline.
[0034] Example 4
[0035] To facilitate public understanding of the present solution, this embodiment takes the low-cost heat exchange system involved in the reduction tail gas recovery system in polysilicon production as an example to further illustrate the present solution.
[0036] In this embodiment, the tail gas recovered from the reduction section needs to be cryogenically treated, the tail gas is cooled from 50°C to -70°C, and sent to the absorption device 1 for separation, and substances such as silicon tetrachloride, trichlorosilane, dichlorosilane, and hydrogen chloride are separated. The remaining purified hydrogen is heated to about 30°C by a multi-stage heater provided on the discharge pipeline 3, and then sent to the next section for recycling.
[0037] refer to Figure 3 In the network heat exchange system for polysilicon production, a four-stage cooler is provided on the feed pipeline 2 connected to the feed inlet 1.1 of the absorption device 1. The four-stage coolers include, from high to low levels, a -70°C dichloromethane cooler, a -40°C Freon cooler, a -10°C Freon cooler, and a 7°C water cooler;
[0038] A first-stage intermediate heat exchanger 9, a second-stage intermediate heat exchanger 10, a third-stage intermediate heat exchanger 11 and a fourth-stage intermediate heat exchanger 12 are respectively provided between the fourth-stage cooler 7 and the absorption device 1, between the third-stage cooler 6 and the fourth-stage cooler 7, between the second-stage cooler 5 and the third-stage cooler 6, and between the first-stage cooler 4 and the second-stage cooler 5. The discharge port 1.2 of the absorption device 1 is connected to the medium inlet of the first-stage intermediate heat exchanger 9 through a pipeline, the medium outlet of the first-stage intermediate heat exchanger 9 is connected to the medium inlet of the second-stage intermediate heat exchanger 10 through a pipeline, the medium outlet of the second-stage intermediate heat exchanger 10 is connected to the medium inlet of the third-stage intermediate heat exchanger 11 through a pipeline, and the medium outlet of the third-stage intermediate heat exchanger 11 is connected to the medium inlet of the fourth-stage intermediate heat exchanger 12 through a pipeline.
[0039] This embodiment takes the recycling and treatment of 400,000 standard cubic meters of tail gas in polysilicon production as an example. If this system is used, the electricity consumption can be saved by 2.164×10 8 kW of electricity consumption, saving approximately RMB 108 million in electricity costs annually.
[0040] Example 5
[0041] The difference between this embodiment and embodiments 1-4 is that, Figure 4 In the network heat exchange system for polysilicon production, a five-stage cooler is provided on the feed pipeline 2 connected to the feed port 1.1 end of the absorption device 1. The five-stage coolers include, from high to low levels, a -70°C dichloromethane cooler, a -40°C Freon cooler, a -10°C Freon cooler, a 7°C water cooler and a 33°C water cooler; a first-stage intermediate heat exchanger 9, a second-stage intermediate heat exchanger 9 are respectively provided between the fifth-stage cooler 8 and the absorption device 1, between the fourth-stage cooler 7 and the fifth-stage cooler 8, between the third-stage cooler 6 and the fourth-stage cooler 7, between the second-stage cooler 5 and the third-stage cooler 6, and between the first-stage cooler 4 and the second-stage cooler 5. The intermediate heat exchanger 10, the third-stage intermediate heat exchanger 11, the fourth-stage intermediate heat exchanger 12 and the fifth-stage intermediate heat exchanger 13 are connected. The discharge port 1.2 of the absorption device 1 is connected to the medium inlet of the first-stage intermediate heat exchanger 9 through a pipeline, the medium outlet of the first-stage intermediate heat exchanger 9 is connected to the medium inlet of the second-stage intermediate heat exchanger 10 through a pipeline, the medium outlet of the second-stage intermediate heat exchanger 10 is connected to the medium inlet of the third-stage intermediate heat exchanger 11 through a pipeline, the medium outlet of the third-stage intermediate heat exchanger 11 is connected to the medium inlet of the fourth-stage intermediate heat exchanger 12 through a pipeline, and the medium outlet of the fourth-stage intermediate heat exchanger 12 is connected to the medium inlet of the fifth-stage intermediate heat exchanger 13 through a pipeline.
[0042] Example 6
[0043] The difference between this embodiment and embodiment 1 is that, Figure 1 In the network heat exchange system in polysilicon production, a two-stage cooler is provided on the feed pipeline 2 connected to the feed port 1.1 end of the absorption device 1, and 33°C cooling water and -40°C Freon medium are respectively passed through the first-stage cooler 4 and the second-stage cooler 5. A first-stage intermediate heat exchanger 9 is additionally provided between the second-stage cooler 5 and the absorption device 1, and a second-stage intermediate heat exchanger 10 is provided between the first-stage cooler 4 and the second-stage cooler 5. The discharge port 1.2 of the absorption device 1 is connected to the medium inlet of the first-stage intermediate heat exchanger 9 through a pipeline, and the medium outlet of the first-stage intermediate heat exchanger 9 is connected to the medium inlet of the second-stage intermediate heat exchanger 10 through a pipeline.
Claims
1. The network heat exchange system in polysilicon production is characterized by: The invention comprises an absorption device (1), wherein the feed port (1.1) of the absorption device (1) is connected to a multi-stage cooler in sequence, wherein the temperature of the cooling medium of the previous stage in the multi-stage cooler is higher than the temperature of the cooling medium of the next stage, and an intermediate heat exchanger is additionally provided between the coolers of adjacent stages and between the highest stage cooler and the absorption device (1), and all the intermediate heat exchangers are connected in sequence through pipelines, and the material cooled in the absorption device (1) serves as the cooling medium of the intermediate heat exchanger, and the temperature of the cooling medium in the intermediate heat exchanger of the previous stage is lower than the temperature of the cooling medium in the next stage.
2. The network heat exchange system for polysilicon production according to claim 1, characterized in that: A two-stage cooler is provided on the feed pipe connected to the feed port (1.1) of the absorption device (1), a first-stage intermediate heat exchanger (9) is additionally provided between the highest-stage cooler and the absorption device (1), a second-stage intermediate heat exchanger (10) is provided between the two-stage coolers, the discharge port (1.2) of the absorption device (1) is connected to the medium inlet of the first-stage intermediate heat exchanger (9) through a pipeline, and the medium outlet of the first-stage intermediate heat exchanger (9) is connected to the medium inlet of the second-stage intermediate heat exchanger (10) through a pipeline.
3. The network heat exchange system for polysilicon production according to claim 2, characterized in that: The highest-level cooler is a heat exchanger with a -70°C dichloromethane medium or a -40°C Freon medium.
4. The network heat exchange system for polysilicon production according to claim 1, characterized in that: A three-stage cooler is provided on the feed pipeline (2) connected to the feed port (1.1) of the absorption device (1). The three-stage coolers include, from high to low levels, a -70°C dichloromethane cooler, a -40°C Freon cooler, and a -10°C Freon cooler. A first-stage intermediate heat exchanger (9), a second-stage intermediate heat exchanger (10), and a third-stage intermediate heat exchanger (11) are respectively provided between the third-stage cooler (6) and the absorption device (1), between the second-stage cooler (5) and the third-stage cooler (6), and between the first-stage cooler (4) and the second-stage cooler (5). The discharge port (1.2) of the absorption device (1) is connected to the medium inlet of the first-stage intermediate heat exchanger (9) through a pipeline, the medium outlet of the first-stage intermediate heat exchanger (9) is connected to the medium inlet of the second-stage intermediate heat exchanger (10) through a pipeline, and the medium outlet of the second-stage intermediate heat exchanger (10) is connected to the medium inlet of the third-stage intermediate heat exchanger (11) through a pipeline.
5. The network heat exchange system for polysilicon production according to claim 1, characterized in that: A four-stage cooler is provided on the feed line (2) connected to the feed port (1.1) of the absorption device (1), and the four-stage cooler comprises, from high to low levels, a -70°C dichloromethane cooler, a -40°C Freon cooler, a -10°C Freon cooler, and a 7°C water cooler; A first-stage intermediate heat exchanger (9), a second-stage intermediate heat exchanger (10), a third-stage intermediate heat exchanger (11), a fourth-stage intermediate heat exchanger (12), and a fifth-stage intermediate heat exchanger (13) are respectively provided between the fourth-stage cooler (7) and the absorption device (1), between the third-stage cooler (6) and the fourth-stage cooler (7), between the second-stage cooler (5) and the third-stage cooler (6), and between the first-stage cooler (4) and the second-stage cooler (5). The discharge port (1.2) of the absorption device (1) is connected to the medium inlet of the first-stage intermediate heat exchanger (9) through a pipeline, the medium outlet of the first-stage intermediate heat exchanger (9) is connected to the medium inlet of the second-stage intermediate heat exchanger (10) through a pipeline, the medium outlet of the second-stage intermediate heat exchanger (10) is connected to the medium inlet of the third-stage intermediate heat exchanger (11) through a pipeline, and the medium outlet of the third-stage intermediate heat exchanger (11) is connected to the medium inlet of the fourth-stage intermediate heat exchanger (12) through a pipeline.
6. The network heat exchange system for polysilicon production according to claim 1, characterized in that: A five-stage cooler is provided on the feed line (2) connected to the feed port (1.1) of the absorption device (1), and the five-stage cooler comprises, from high to low levels, a -70°C dichloromethane cooler, a -40°C Freon cooler, a -10°C Freon cooler, a 7°C water cooler, and a 33°C water cooler; A first-stage intermediate heat exchanger (9), a second-stage intermediate heat exchanger (10), a third-stage intermediate heat exchanger (11), a fourth-stage intermediate heat exchanger (12) and a fifth-stage intermediate heat exchanger (13) are respectively provided between the fifth-stage cooler (8) and the absorption device (1), between the fourth-stage cooler (7) and the fifth-stage cooler (8), between the third-stage cooler (6) and the fourth-stage cooler (7), between the second-stage cooler (5) and the third-stage cooler (6), and between the first-stage cooler (4) and the second-stage cooler (5). The discharge port ( 1.2) The medium inlet of the first-stage intermediate heat exchanger (9) is connected through a pipeline, the medium outlet of the first-stage intermediate heat exchanger (9) is connected to the medium inlet of the second-stage intermediate heat exchanger (10) through a pipeline, the medium outlet of the second-stage intermediate heat exchanger (10) is connected to the medium inlet of the third-stage intermediate heat exchanger (11) through a pipeline, the medium outlet of the third-stage intermediate heat exchanger (11) is connected to the medium inlet of the fourth-stage intermediate heat exchanger (12) through a pipeline, and the medium outlet of the fourth-stage intermediate heat exchanger (12) is connected to the medium inlet of the fifth-stage intermediate heat exchanger (13) through a pipeline.
7. The network heat exchange system for polysilicon production according to claim 1, characterized in that: A first-stage cooler (4) and a second-stage cooler (5) are provided on the feed line (2) connected to the feed port (1.1) of the absorption device (1), through which 33°C cooling water and -40°C Freon medium respectively flow; a first-stage intermediate heat exchanger (9) is additionally provided between the second-stage cooler (5) and the absorption device (1); a second-stage intermediate heat exchanger (10) is provided between the first-stage cooler (4) and the second-stage cooler (5); the discharge port (1.2) of the absorption device (1) is connected to the medium inlet of the first-stage intermediate heat exchanger (9) through a pipeline, and the medium outlet of the first-stage intermediate heat exchanger (9) is connected to the medium inlet of the second-stage intermediate heat exchanger (10) through a pipeline.