Low-cost heat exchange system for polycrystalline silicon production
Through a combination system of multi-stage cooler and heater, low-grade refrigerant cooling and high-grade refrigerant heating are used to solve the problem of high-grade refrigerant demand in polysilicon production, a low-cost heat exchange system is realized, and production costs and energy consumption are reduced.
Patent Information
- Application Number
- CN202422350258.6
- 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 current production of polysilicon has a large demand for medium and high-grade refrigerants, which leads to high load on refrigerant equipment and high cost of heat exchange system.
A combination system of multi-stage cooler and heater is adopted to cool down materials and heat up high-stage refrigerant by using low-grade refrigerant to reduce the use of high-grade refrigerant, and the medium after the heat exchange of refrigerant in the multi-stage cooler is used as the heat medium in the heating stage to reduce the use of heat medium.
It effectively reduces the production cost of polysilicon production, saves the use of high-quality refrigerants, and realizes efficient energy utilization through equipment modification.
Smart Images
Figure CN223191860U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of efficient energy utilization in polysilicon production, in particular to a low-cost heat exchange system for 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. The main reasons are:
[0004] ① 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;
[0005] ② 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. It is not economical to operate it all year round.
[0006] 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.
[0007] After investigation, it was found that the higher the grade of the refrigerant, the higher the production cost.
[0008] Technicians in this industry are still exploring to find better processes, achieve efficient use of energy, and reduce production costs. Utility Model Content
[0009] Based on the above background, the proposer of the present invention considers that the total cooling capacity of the refrigerant is certain during the entire condensation process of the material, so it is possible to consider using low-grade refrigerant to cool the system as much as possible, so as to save the subsequent use of refrigerant and achieve the purpose of saving production costs.
[0010] The purpose of the present invention is to provide a low-cost heat exchange method and system for polysilicon production, which is suitable for processes that require cooling the material first (generally filtering, separation, etc. are required after cooling) and then heating it, or heating it first and then cooling it. It can realize the comprehensive utilization of refrigerants, save the use of high-quality refrigerants, and reduce production costs.
[0011] The utility model aims to solve the problems in the prior art of large demand for high-grade refrigerant, large load on the electric ice machine corresponding to the high-grade refrigerant, and high cost of the heat exchange system.
[0012] In order to achieve the above-mentioned purpose of the invention, the technical solution of the present utility model is as follows:
[0013] A low-cost heat exchange system for polysilicon production includes an absorption device, a multi-stage cooler is provided on a feed pipeline connected to the feed inlet end of the absorption device, and a multi-stage heater is provided on a discharge pipeline connected to the discharge outlet end of the absorption device. 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; the temperature of the heating medium of the previous stage in the multi-stage heater is lower than the temperature of the heating medium of the next stage; and at least one cooler medium outlet is connected to a heater medium inlet through a pipeline.
[0014] Furthermore, a two-stage cooler is provided on the feed pipeline connected to the feed port end of the absorption device, and a two-stage heater is provided on the discharge pipeline connected to the discharge port end of the absorption device. The medium outlet of the highest-level cooler is connected to the medium inlet of the first-level heater through a pipeline, and the medium outlet of the previous-level cooler is connected to the medium inlet of the second-level heater through a pipeline.
[0015] Furthermore, the highest-level cooler is a heat exchanger with a -70°C dichloromethane medium or a -40°C Freon medium.
[0016] 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 corresponding three-stage heater is provided on the discharge pipeline connected to the discharge port end of the absorption device, the medium outlet of the -70°C dichloromethane cooler is connected to the medium inlet of the first-stage heater through a pipeline, the medium outlet of the -40°C Freon cooler is connected to the medium inlet of the second-stage heater through a pipeline; the medium outlet of the -10°C Freon cooler is connected to the medium inlet of the third-stage heater through a pipeline.
[0017] 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 corresponding four-stage heater is provided on the discharge pipeline connected to the discharge port end of the absorption device, the medium outlet of the -70°C dichloromethane cooler is connected to the medium inlet of the first-stage heater through a pipeline, the medium outlet of the -40°C Freon cooler is connected to the medium inlet of the second-stage heater through a pipeline, the medium outlet of the -10°C Freon cooler is connected to the medium inlet of the third-stage heater through a pipeline, and the medium outlet of the 7°C water cooler is connected to the medium inlet of the fourth-stage heater through a pipeline.
[0018] 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 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 corresponding five-stage heater is provided on the discharge pipeline connected to the discharge port end of the absorption device, the medium outlet of the -70°C dichloromethane cooler is connected to the medium inlet of the first-stage heater through a pipeline, the medium outlet of the -40°C Freon cooler is connected to the medium inlet of the second-stage heater through a pipeline, the medium outlet of the -10°C Freon cooler is connected to the medium inlet of the third-stage heater through a pipeline, the medium outlet of the 7°C water cooler is connected to the medium inlet of the fourth-stage heater through a pipeline, and the medium outlet of the 33°C water cooler is connected to the medium inlet of the fifth-stage heater through a pipeline.
[0019] Furthermore, the feed pipeline connected to the feed port end of the absorption device is provided with a two-stage cooler including a -40°C Freon cooler and a 33°C water cooler; the discharge pipeline connected to the discharge port end of the absorption device is provided with corresponding two-stage heaters, the medium outlet of the -40°C Freon cooler is connected to the medium inlet of the first-stage heater through a pipeline, and the medium outlet of the 33°C water cooler is connected to the medium inlet of the second-stage heater through a pipeline.
[0020] Beneficial effects of the utility model:
[0021] 1. This utility model proposes a low-cost heat exchange system for polysilicon production, which is particularly suitable for polysilicon production (cold hydrogenation section, waste gas recovery section of reduction section, etc.), where the material needs to be cooled first, then separated after cooling, and the light component needs to be heated after removing the heavy component. The heated light component is then reused in the production system. This low-cost heat exchange system first uses a multi-stage cooler to cool the material, minimizing the use of high-grade refrigerants (especially -40°C Freon refrigerant and -70°C dichloromethane refrigerant), which can reduce the cost of the heat exchange system. At the same time, the material is sent to the absorption device after deep cooling, and after separation or absorption and other treatments, it needs to enter the next process. This process requires the purified material to be heated (generally to about 30°C), that is, the material needs to be heated. In this solution, the refrigerant after heat exchange in the previous multi-stage cooler is used as the heat medium in the heating stage, which can also reduce the use of heat medium. In addition, the medium after heat exchange in the multi-stage heater is used to prepare the refrigerant, which requires lower power consumption than directly preparing the refrigerant, and can also reduce the production cost of the heat exchange system.
[0022] 2. In the present invention, the distance between the "multi-stage cooling" zone and the "multi-stage heating" zone of the low-cost heat exchange system is relatively close, fewer pipelines are required, and the consumption cost is low.
[0023] 3. The present invention is convenient for modifying the equipment on the original system without replacing all the equipment, and is widely used. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 It is a structural diagram of Example 1.
[0025] Figure 2 It is a structural diagram of Example 2.
[0026] Figure 3 It is a structural diagram of Example 4.
[0027] Figure 4 It is a structural diagram of Example 5.
[0028] Figure 5 It is a structural diagram of Example 6.
[0029] Figure 6 It is a structural diagram of Example 7.
[0030] Among them, 1. Absorption device; 2. Feed pipeline; 3. Discharge pipeline; 4. -70℃ dichloromethane cooler; 5. -40℃ Freon cooler; 6. -10℃ Freon cooler; 7. 7℃ water cooler; 8. 33℃ water cooler; 9. First-stage heater; 10. Second-stage heater; 11. Third-stage heater; 12. Fourth-stage heater; 13. Fifth-stage heater; 14. First-stage cooler; 15. Second-stage cooler; 1.1. Feed port; 1.2. Discharge port. DETAILED DESCRIPTION
[0031] 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.
[0032] Example 1
[0033] This embodiment is the most basic implementation method, a low-cost heat exchange system for polysilicon production, which relates to the technical field of efficient energy utilization in polysilicon production, including an absorption device 1. Figure 1 A first-stage cooler 14 and a second-stage cooler 15 are provided on the feed pipeline 2 connected to the feed port 1.1 end of the absorption device 1, and a first-stage heater 9 and a second-stage heater 10 are provided on the discharge pipeline 3 connected to the discharge port 1.2 end of the absorption device 1. The temperature of the cooling medium in the first-stage cooler 14 is higher than the temperature of the cooling medium in the second-stage cooler 15; the temperature of the heating medium in the first-stage heater 9 is lower than the temperature of the heating medium in the second-stage heater 10, and the medium outlet of the second-stage cooler 15 is connected to the medium inlet of the first-stage heater 9 through a pipeline.
[0034] In actual production, based on on-site conditions or specific requirements, at least one cooler medium outlet can be selected to connect to the medium inlet of a heater through a pipeline. It is preferred to reuse the heat exchanged medium in the high-grade cooler as the heating medium of the heater.
[0035] Example 2
[0036] The difference between this embodiment and embodiment 1 is that, Figure 2 The feed pipeline 2 connected to the feed port 1.1 end of the absorption device 1 is provided with a first-stage cooler 14 and a second-stage cooler 15, and the discharge pipeline 3 connected to the discharge port 1.2 end of the absorption device 1 is provided with a first-stage heater 9 and a second-stage heater 10. The medium outlet of the second-stage cooler 15 is connected to the medium inlet of the first-stage heater 9 through a pipeline, and the medium outlet of the first-stage cooler 14 is connected to the medium inlet of the second-stage heater 10 through a pipeline.
[0037] Example 3
[0038] The difference between this embodiment and embodiment 1-2 is that the highest-level cooler is a heat exchanger with a -70°C dichloromethane medium or a -40°C Freon medium.
[0039] Example 4
[0040] The difference between this embodiment and embodiment 1-3 is that, Figure 3 The feed pipeline 2 connected to the feed port 1.1 end of the absorption device 1 is provided with a three-stage cooler, and the three-stage coolers include, from high to low levels, a -70°C dichloromethane cooler 4, a -40°C Freon cooler 5 and a -10°C Freon cooler 6; the discharge pipeline 3 connected to the discharge port 1.2 end of the absorption device 1 is provided with corresponding three-stage heaters, the medium outlet of the -70°C dichloromethane cooler 4 is connected to the medium inlet of the first-stage heater 9 through a pipeline, the medium outlet of the -40°C Freon cooler 5 is connected to the medium inlet of the second-stage heater 10 through a pipeline; the medium outlet of the -10°C Freon cooler 6 is connected to the medium inlet of the third-stage heater 11 through a pipeline.
[0041] Example 5
[0042] The difference between this embodiment and embodiments 1-4 is that, Figure 4 The feed pipeline 2 connected to the feed port 1.1 end of the absorption device 1 is provided with a four-stage cooler, and the four-stage coolers include, from high to low levels, a -70°C dichloromethane cooler 4, a -40°C Freon cooler 5, a -10°C Freon cooler 6 and a 7°C water cooler 7; the discharge pipeline 3 connected to the discharge port 1.2 end of the absorption device 1 is provided with corresponding four-stage heaters, the medium outlet of the -70°C dichloromethane cooler 4 is connected to the medium inlet of the first-stage heater 9 through a pipeline, the medium outlet of the -40°C Freon cooler 5 is connected to the medium inlet of the second-stage heater 10 through a pipeline, the medium outlet of the -10°C Freon cooler 6 is connected to the medium inlet of the third-stage heater 11 through a pipeline, and the medium outlet of the 7°C water cooler 7 is connected to the medium inlet of the fourth-stage heater 12 through a pipeline.
[0043] Example 6
[0044] 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.
[0045] 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.
[0046] refer to Figure 5 The feed line 2 connected to the feed port 1.1 end of the absorption device 1 is provided with a five-stage cooler. The five-stage cooler includes, from low to high levels, a 33°C water cooler 8, a 7°C water cooler 7, a -10°C Freon cooler 6, a -40°C Freon cooler 5 and a -70°C dichloromethane cooler, and cools the tail gas to 33°C, 10°C, -8°C, -35°C, and finally to -70°C. A corresponding five-stage heater is provided on the discharge pipeline 3 connected to the discharge port 1.2 end of the absorption device 1. The medium outlet of the -70°C dichloromethane cooler 4 is connected to the medium inlet of the first-stage heater 9 through a pipeline, the medium outlet of the -40°C Freon cooler 5 is connected to the medium inlet of the second-stage heater 10 through a pipeline, the medium outlet of the -10°C Freon cooler 6 is connected to the medium inlet of the third-stage heater 11 through a pipeline, the medium outlet of the 7°C water cooler 7 is connected to the medium inlet of the fourth-stage heater 12 through a pipeline, and the medium outlet of the 33°C water cooler 8 is connected to the medium inlet of the fifth-stage heater 13 through a pipeline.
[0047] This embodiment takes the recycling and treatment of 200,000 standard cubic meters of tail gas in polysilicon production as an example. If this system is used, the electricity consumption can be saved by 1.032×10 8 kW of electricity consumption, saving approximately RMB 54 million in electricity costs annually.
[0048] Example 7
[0049] The difference between this embodiment and embodiment 1-6 is that, Figure 6 The feed pipeline 2 connected to the feed port 1.1 end of the absorption device 1 is provided with a two-stage cooler, a -40°C Freon cooler 5 and a 33°C water cooler 8; the discharge pipeline 3 connected to the discharge port 1.2 end of the absorption device 1 is provided with corresponding two-stage heaters, the medium outlet of the -40°C Freon cooler 5 is connected to the medium inlet of the first-stage heater 9 through a pipeline, and the medium outlet of the 33°C water cooler 8 is connected to the medium inlet of the second-stage heater 10 through a pipeline.
Claims
1. A low-cost heat exchange system for polysilicon production, characterized by: The invention comprises an absorption device (1), wherein a multi-stage cooler is provided on a feed pipeline (2) connected to a feed port (1.1) of the absorption device (1), and a multi-stage heater is provided on a discharge pipeline (3) connected to a discharge port (1.2) of the absorption device (1). The temperature of the cooling medium of the first stage in the multi-stage cooler is higher than the temperature of the cooling medium of the second stage; the temperature of the heating medium of the first stage in the multi-stage heater is lower than the temperature of the heating medium of the second stage; and at least one cooler medium outlet is connected to a heater medium inlet via a pipeline.
2. A low-cost heat exchange system for polysilicon production according to claim 1, characterized in that: 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 a two-stage heater is provided on the discharge pipeline (3) connected to the discharge port (1.2) end of the absorption device (1). The medium outlet of the highest-stage cooler is connected to the medium inlet of the first-stage heater (9) through a pipeline, and the medium outlet of the previous-stage cooler is connected to the medium inlet of the second-stage heater (10) through a pipeline.
3. The low-cost 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 low-cost 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) end of the absorption device (1), and the three-stage coolers include, from high to low levels, a -70°C dichloromethane cooler (4), a -40°C Freon cooler (5), and a -10°C Freon cooler (6); a corresponding three-stage heater is provided on the discharge pipeline (3) connected to the discharge port (1.2) end of the absorption device (1); the medium outlet of the -70°C dichloromethane cooler (4) is connected to the medium inlet of the first-stage heater (9) through a pipeline, the medium outlet of the -40°C Freon cooler (5) is connected to the medium inlet of the second-stage heater (10) through a pipeline; and the medium outlet of the -10°C Freon cooler (6) is connected to the medium inlet of the third-stage heater (11) through a pipeline.
5. The low-cost heat exchange system for polysilicon production according to claim 1, characterized in that: A four-stage cooler is provided on the feed pipeline (2) connected to the feed port (1.1) end of the absorption device (1), and the four-stage coolers include, from high to low levels, a -70°C dichloromethane cooler (4), a -40°C Freon cooler (5), a -10°C Freon cooler (6) and a 7°C water cooler (7); a corresponding four-stage heater is provided on the discharge pipeline (3) connected to the discharge port (1.2) end of the absorption device (1), the medium outlet of the -70°C dichloromethane cooler (4) is connected to the medium inlet of the first-stage heater (9) through a pipeline, the medium outlet of the -40°C Freon cooler (5) is connected to the medium inlet of the second-stage heater (10) through a pipeline, the medium outlet of the -10°C Freon cooler (6) is connected to the medium inlet of the third-stage heater (11) through a pipeline, and the medium outlet of the 7°C water cooler (7) is connected to the medium inlet of the fourth-stage heater (12) through a pipeline.
6. The low-cost heat exchange system for polysilicon production according to claim 1, characterized in that: The feed line (2) connected to the feed port (1.1) of the absorption device (1) is provided with a five-stage cooler, and the five-stage coolers include, from high to low levels, a -70°C dichloromethane cooler (4), a -40°C Freon cooler (5), a -10°C Freon cooler (6), a 7°C water cooler (7) and a 33°C water cooler (8); the discharge line (3) connected to the discharge port (1.2) of the absorption device (1) is provided with a corresponding five-stage heater, and the medium outlet of the -70°C dichloromethane cooler (4) is provided with a five-stage heater. The medium outlet of the -40°C Freon cooler (5) is connected to the medium inlet of the second stage heater (10) through a pipeline, the medium outlet of the -10°C Freon cooler (6) is connected to the medium inlet of the third stage heater (11) through a pipeline, the medium outlet of the 7°C water cooler (7) is connected to the medium inlet of the fourth stage heater (12) through a pipeline, and the medium outlet of the 33°C water cooler (8) is connected to the medium inlet of the fifth stage heater (13) through a pipeline.
7. The low-cost heat exchange system for polysilicon production according to claim 1, characterized in that: A feed pipeline (2) connected to the feed port (1.1) of the absorption device (1) is provided with a two-stage cooler, namely, a -40°C Freon cooler (5) and a 33°C water cooler (8); a discharge pipeline (3) connected to the discharge port (1.2) of the absorption device (1) is provided with corresponding two-stage heaters, the medium outlet of the -40°C Freon cooler (5) is connected to the medium inlet of the first-stage heater (9) through a pipeline, and the medium outlet of the 33°C water cooler (8) is connected to the medium inlet of the second-stage heater (10) through a pipeline.