Production system for preparing refrigerant by using surplus steam in polycrystalline silicon production
By using the production system for preparing refrigerant by leveraging surplus steam in polysilicon production and using ammonia-N,N-diethylaniline solution as the medium, the problems of poor stability and steam waste of screw compressors in traditional polysilicon production are solved, and efficient recovery of cooling capacity and reduction of refrigeration costs are achieved.
Patent Information
- Application Number
- CN202422195634.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-09
- Publication Date
- 2025-09-02
- Estimated Expiration
- 2034-09-09
AI Technical Summary
In the production of traditional polysilicon, the screw compressor has poor stability, complex equipment and high cost, high electricity consumption of ice machines, serious steam waste, unstable system, and insufficient safety.
The production system for preparing refrigerant using surplus steam in polycrystalline silicon production uses ammonia-N,N-diethylaniline solution as the medium, and the steam is converted into liquid ammonia through shell and tube heat exchangers and heating tubes for refrigeration, reducing the use of ice machines and recovering heat.
It reduces the operating cost of refrigeration equipment, reduces steam waste, improves the stability and safety of the system, and achieves efficient utilization of cooling capacity.
Smart Images
Figure CN223295053U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of energy recovery and utilization equipment, and particularly relates to a production system for preparing refrigerant by utilizing surplus steam in polysilicon production. Background Art
[0002] In the traditional polysilicon production industry, Freon is often used as a cryogenic refrigerant, and the refrigeration method is a screw compressor pressurization method. This has been common in the polysilicon industry and has been used for many years. Although the use of screw compressors to compress Freon gas phase refrigeration is widely used, there are still many problems that need to be solved, such as:
[0003] 1. The stability of screw compressors is difficult to guarantee, and the inlet is often filled with liquid or the rotor or winding high temperature alarm trips and stops.
[0004] 2. The evaporative cooling and economizer storage tank equipment in the post-system of the screw compressor are of many types, with complex structures, high investment costs, and many vulnerable parts;
[0005] 3. The use of compressors, evaporative cooling and other equipment will result in very high power consumption during long-term operation. For example, for a -10℃ ice machine with a cooling capacity of 3,000kW, its motor power is about 900kW, plus the consumption of evaporative cooling, the COP value during actual operation is generally less than 3, which means that the annual electricity bill for an ice machine can be as high as 4 million. With the continuous improvement of polysilicon production capacity, the number of supporting ice machines is increasing. The annual electricity consumption of ice machines in a 200,000-ton polysilicon production plant can reach over 100 million yuan.
[0006] For the above reasons, technical personnel in the industry are still constantly looking for refrigeration equipment with simple structure and lower operating costs or refrigeration technology with better process to replace or partially replace the current ice machines to provide cooling for the system and achieve the goal of reducing costs.
[0007] Furthermore, with the continuous increase in the output of reduced products from polysilicon production and the decreasing unit steam consumption, our company currently has a surplus of 70 t / h of steam in Phases I and II. With the completion and commissioning of Phase III, this surplus steam will increase to 132 t / h. To maintain system balance, a large amount of steam must be cooled through the Phase I reduction furnace, the chassis plate heat exchanger, and the Phase II reduction air cooler. This method not only wastes a significant amount of heat energy but also requires significant circulating water and electricity consumption for processing, further increasing the system load. Furthermore, due to the capacity limitations of the plate heat exchanger and air cooler, the chassis water tank often overpressures and becomes uncontrollable, resulting in high chassis water temperatures. Overheating and vaporization of return water are also becoming increasingly frequent, posing significant challenges to safe and stable operation. Utility Model Content
[0008] The inventors of this utility model discovered through research that ammonia can volatilize at temperatures dozens of degrees below zero and has a high enthalpy, absorbing large amounts of heat, thereby achieving refrigeration. Therefore, they considered using ammonia as a refrigerant to absorb and volatilize heat, thereby providing cooling for the system. Furthermore, the ammonia solvent selected was an N,N-diethylaniline solution, which readily dissolves ammonia at room temperature, readily volatilizes at temperatures above 100°C, and does not readily vaporize between room temperature and 130°C.
[0009] In order to solve the above-mentioned technical problems, the utility model proposes a production system for preparing refrigerant using surplus steam in polysilicon production. The surplus steam generated in polysilicon production is used to prepare refrigerant through an ammonia-N,N-diethylaniline solution medium. The entire production system has a simple structure and is easy to implement. It can reduce the use of some ice machines and consume some surplus steam at the same time, thereby achieving the purpose of reducing production costs.
[0010] The specific technical solutions are as follows:
[0011] A production system for preparing refrigerant using surplus steam in polysilicon production includes a storage tank I for storing ammonia-solvent, which is connected to a cooling device and a liquid ammonia refrigerant storage tank in sequence. A jacket or heating pipe is provided on the outside of the storage tank I, or a heating pipe is provided on the inside of the storage tank I, and the jacket or heating pipe is connected to a steam pipeline.
[0012] Furthermore, the cooling device is a shell and tube heat exchanger with cooling water flowing therethrough.
[0013] Furthermore, the shell and tube heat exchanger is a heat exchanger through which a 33°C cooling water medium flows.
[0014] Furthermore, the liquid ammonia refrigerant storage tank is a storage tank storing high-pressure liquid ammonia.
[0015] Furthermore, the heating tube is a coil or a tube array.
[0016] Furthermore, the exterior of the liquid ammonia refrigerant storage tank is coated with a heat insulation layer, and an insulation sleeve is provided on the exterior of the heat insulation layer.
[0017] Furthermore, the liquid ammonia refrigerant storage tank is connected to the medium inlet of the user-end heat exchanger through pipeline I, the medium outlet of the user-end heat exchanger is connected to the absorption device containing dissolved ammonia solvent through pipeline II, and the outlet of the absorption device is connected to the booster pump and then connected to the storage tank I through pipeline III.
[0018] Furthermore, the storage tank I is provided with a liquid ammonia supply pipeline and a solvent supply pipeline.
[0019] Furthermore, a compressor is provided on the pipeline between the storage tank I and the cooling device.
[0020] Beneficial effects of the utility model:
[0021] 1. This utility model proposes a production system for producing refrigerant using excess steam from polysilicon production. The excess steam generated during polysilicon production heats the ammonia-solvent solution stored in storage tank I, causing the ammonia to absorb heat and vaporize. Tank I is then subjected to high pressure (approximately 1.5 MPa). The ammonia is then liquefied into liquid ammonia by a cooling device. Finally, the high-pressure liquid ammonia, which has accumulated cooling capacity, is temporarily stored in a liquid ammonia refrigerant tank for use by end users. Furthermore, a steam jacket or heating pipe is installed on the outside of tank I, or inside tank I, to facilitate the steam-ammonia heat exchange process within the system. This simple and ingenious structure is suitable for producing refrigerant using excess steam from polysilicon production, requiring minimal equipment and significantly reducing costs. In this solution, an N,N-diethylaniline solution can be used as the reagent for dissolving ammonia.
[0022] Second, in the present invention, the cooling device is a shell-and-tube heat exchanger with cooling water flowing through it. This cooling water can be used to cool the gaseous ammonia generated during polysilicon production, facilitating heat recovery. The preferred shell-and-tube heat exchanger is one that flows through a 33°C cooling water medium, which can condense the refrigerant (ammonia) from a gaseous state to a liquid state.
[0023] 3. In the present invention, the heating tubes are coils or tubes in a tube array to ensure the heat exchange efficiency of the equipment.
[0024] 4. In the present invention, the exterior of the liquid ammonia refrigerant storage tank is coated with a heat-insulating layer, and a heat-insulating sleeve is provided on the exterior of the heat-insulating layer to prevent loss of cold.
[0025] 5. In the present invention, the liquid ammonia refrigerant storage tank is connected to the medium inlet of the user-end heat exchanger through pipeline I, and the medium outlet of the user-end heat exchanger is connected to the absorption device containing dissolved ammonia solvent through pipeline II. The outlet of the absorption device is connected to the booster pump and then connected to the storage tank I through pipeline III. The liquid ammonia with cooling capacity is sent to the user end. After heat exchange, the liquid ammonia is vaporized and sent to the absorption device through pipeline II. The solvent in the absorption device can absorb ammonia and be sent back to the storage tank I through the booster pump, thereby realizing the recycling of the medium-ammonia and achieving the effect of energy saving and emission reduction.
[0026] 6. In the present invention, liquid ammonia and solvent are replenished through the liquid ammonia replenishment pipeline and solvent replenishment pipeline provided on the storage tank I, and the solvent is preferably N,N-diethylaniline solution. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 It is a structural diagram of the present utility model.
[0028] Figure 2 It is a schematic diagram of the production system structure of another embodiment.
[0029] Figure 3It is a schematic diagram of the production system structure of another embodiment.
[0030] Figure 4 This is a structural diagram of storage tank I (with built-in tubular heating tubes).
[0031] Figure 5 This is a schematic diagram of the structure of another embodiment of storage tank I (with built-in coil heating tube).
[0032] Figure 6 This is a partial illustration of the tank wall of a liquid ammonia refrigerant storage tank.
[0033] Figure 7 It is a schematic diagram of the production system structure of another preferred embodiment.
[0034] Among them, 1. Steam pipeline; 2. Storage tank I; 3. Cooling device; 4. Liquid ammonia refrigerant storage tank; 5. Jacket; 6. Heating pipe; 7. Pipeline I; 8. User-end heat exchanger; 9. Pipeline II; 10. Absorption device; 11. Booster pump; 12. Pipeline III; 13. Liquid ammonia supply pipeline; 14. Solvent replenishment pipeline; 15. Compressor; 3.1. Cooling water medium inlet pipe; 4.1. Insulation layer; 4.2. Insulation jacket; 6.1. Coil; 6.2. Tube; 8.1. Medium inlet; 8.2. Medium outlet; 10.1. Outlet. DETAILED DESCRIPTION
[0035] 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.
[0036] Example 1
[0037] A production system for preparing refrigerant using surplus steam in polysilicon production belongs to the technical field of energy recovery and utilization equipment, and includes a storage tank Ⅰ2 for storing ammonia-solvent, which is connected to a cooling device 3 and a liquid ammonia refrigerant storage tank 4 in sequence. A jacket 5 is provided on the outside of the storage tank Ⅰ2, and the jacket 5 is connected to a steam pipeline 1.
[0038] This embodiment is a basic implementation method, refer to Figure 1 Storage tank I2 stores a mixed solution of ammonia and N,N-diethylaniline solution (solvent). Excess steam generated during polysilicon production is collected and transported to jacket 5 via steam pipeline 1. The steam-filled jacket 5 heats storage tank I2, vaporizing the ammonia in the mixed solution into ammonia gas. The pressure is maintained during vaporization (typically 1.5 MPa), and then cooled by cooling device 3. Under low-temperature, high-pressure conditions, the ammonia gas is converted into liquid ammonia and temporarily stored in liquid ammonia refrigerant tank 4. The liquid ammonia in tank 4 then serves as refrigerant for end-user use. The entire production system has a simple structure, minimal equipment, and relatively low electricity costs for equipment operation.
[0039] Preferably, the cooling device 3 is a shell and tube heat exchanger with cooling water passing through it.
[0040] Example 2
[0041] The difference between this embodiment and embodiment 1 is that a heating pipe 6 is provided inside the storage tank Ⅰ 2. Figure 4 or Figure 5 .
[0042] In actual production, the heating tube 6 can be designed as a coil 6.1 or a tube array 6.2, such as Figure 4 , the heating tube 6 is a built-in tube 6.2; Figure 5 The heating tube 6 is a built-in coil 6.1.
[0043] Of course, the heating tube 6 can also be designed on the outside of the storage tank Ⅰ 2 as needed, and the heating tube 6 can be closely attached to the outer wall of the storage tank Ⅰ 2 .
[0044] Example 3
[0045] The difference between this embodiment and embodiment 1-2 is that the shell and tube heat exchanger is a heat exchanger with a 33°C cooling water medium. The liquid ammonia refrigerant storage tank 4 is a storage tank storing high-pressure liquid ammonia. This production system can produce high-grade cryogenic refrigerant.
[0046] Example 4
[0047] The difference between this embodiment and embodiments 1-3 is that the exterior of the liquid ammonia refrigerant storage tank 4 is coated with a heat insulation layer 4.1, and the exterior of the heat insulation layer 4.1 is provided with a heat preservation sleeve 4.2. Figure 6 , reducing the loss of cold energy in the liquid ammonia refrigerant storage tank 4.
[0048] Example 5
[0049] The difference between this embodiment and embodiment 1-4 is that the liquid ammonia refrigerant storage tank 4 is connected to the medium inlet 8.1 of the user-end heat exchanger 8 through the pipeline I7. Figure 2 The medium outlet 8.2 of the user-side heat exchanger 8 is connected to an absorption device 10 containing a dissolved ammonia solvent via a pipeline II 9. The outlet 10.1 of the absorption device 10 is connected to a booster pump 11 and then to a storage tank I 2 via a pipeline III 12. The booster pump 11 is preferably a hydraulic booster pump.
[0050] Example 6
[0051] The difference between this embodiment and embodiments 1-5 is that the storage tank I2 is provided with a liquid ammonia supply line 13 for supplying liquid ammonia. Figure 3 The storage tank Ⅰ2 is also connected to a solvent replenishing pipeline 14 for replenishing the N,N-diethylaniline solution solvent.
[0052] Example 7
[0053] The difference between this embodiment and embodiments 1-6 is that a compressor 15 is provided on the pipeline between the storage tank Ⅰ 2 and the cooling device 3. Figure 7 .
[0054] Example 8
[0055] To facilitate public understanding of the present solution, this embodiment takes a production system for preparing refrigerant using surplus steam in polysilicon production as an example to further illustrate the present solution.
[0056] refer to Figure 3 , including a storage tank Ⅰ2 for storing ammonia-solvent, the storage tank Ⅰ2 is connected to the cooling device 3 and the liquid ammonia refrigerant storage tank 4 in sequence, a jacket 5 is provided on the outside of the storage tank Ⅰ2, the jacket 5 is connected to the steam pipeline 1, the cooling device 3 is a shell and tube heat exchanger with cooling water, and a liquid ammonia supply pipeline 13 and a solvent supply pipeline 14 are provided on the storage tank Ⅰ2.
[0057] In this embodiment, the shell and tube heat exchanger is a heat exchanger through which a 33° C. cooling water medium flows, and the liquid ammonia refrigerant storage tank 4 is a storage tank storing liquid ammonia.
[0058] In this embodiment, reference Figure 6 The exterior of the liquid ammonia refrigerant storage tank 4 is coated with a heat insulation layer 4.1, and an insulation sleeve 4.2 is provided on the exterior of the heat insulation layer 4.1.
[0059] In this embodiment, the liquid ammonia refrigerant storage tank 4 is connected to the medium inlet 8.1 of the user-end heat exchanger 8 through pipeline I7, and the medium outlet 8.2 of the user-end heat exchanger 8 is connected to the absorption device 10 containing dissolved ammonia solvent through pipeline II9. The outlet 10.1 of the absorption device 10 is connected to the booster pump 11 and then connected to the storage tank I2 through pipeline III12.
[0060] In this embodiment, a mixed solution of ammonia and N,N-diethylaniline solution (solvent) is stored in storage tank I2, and surplus steam generated in the production of polysilicon is collected to heat storage tank I2 through a steam jacket 5, which can process a portion of the surplus steam of about 70t / h generated in the company's original first and second phase production lines, and vaporize the ammonia in the mixed solution into ammonia gas, and vaporize and maintain the pressure to 1.5MPa. When the pressure is insufficient, a liquid ammonia booster pump 15 can be installed on the pipeline between storage tank I2 and the cooling device 3, and then the ammonia is cooled by the cooling device 3. The cooling device 3 is a shell and tube heat exchanger with cooling water, which has a 33°C cooling water medium. Under low temperature and high pressure conditions, the ammonia gas is converted into liquid ammonia and temporarily stored in the liquid ammonia refrigerant storage tank 4. The exterior of the liquid ammonia refrigerant storage tank 4 is coated with an insulation layer 4.1, and an insulation sleeve 4.2 is provided on the exterior of the insulation layer 4.1. The insulation layer 4.1 and the insulation sleeve 4.2 can reduce the loss of cold energy. At this time, the liquid ammonia in the liquid ammonia refrigerant storage tank 4 serves as refrigerant for use by the user end.
[0061] In this embodiment, reference Figure 3 Taking a user-side heat exchanger 8 as an example, this solution will be further explained. Liquid ammonia refrigerant storage tank 4 is connected to the medium inlet 8.1 of user-side heat exchanger 8 via pipeline I7. High-pressure liquid ammonia rapidly vaporizes and converts to -15°C ammonia after pressure release and heat absorption at the user-side. This then undergoes heat exchange with the material at the user-side. After the heat exchange is complete, the medium outlet 8.2 of user-side heat exchanger 8 is connected via pipeline II9 to an absorption device 10 containing a dissolved ammonia solvent. The outlet 10.1 of absorption device 10 is connected to a booster pump 11 and then to storage tank I2 via pipeline III 12. After the refrigerant passes through user-side heat exchanger 8, the liquid ammonia absorbs heat and converts it into gaseous ammonia. This is then delivered to absorption device 10 via pipeline II9. Absorption device 10 contains an N,N-diethylaniline solution, which dissolves ammonia to form an ammonia-N,N-diethylaniline mixed solution. This mixed solution is then pumped to storage tank I2 via booster pump 11, achieving medium recycling. The entire production system involves a simple structure, few devices, relatively low electricity costs for equipment operation, and is easy to automate.
[0062] Compared with the traditional solution using refrigeration machines, taking the preparation of 6000kW of refrigerant as an example, this system can save 18 million kW / year, and reduce the total production cost by about 9 million yuan / year. In addition, this refrigerant production system has a simple structure and small moving equipment, and is not prone to the risk of system shutdown, ensuring the safe and stable operation of the production system and reducing operating costs.
Claims
1. A production system for preparing refrigerant using excess steam from polysilicon production, characterized by: The invention comprises a storage tank I (2) for storing an ammonia-solvent, the storage tank I (2) being connected in sequence to a cooling device (3) and a liquid ammonia refrigerant storage tank (4), a jacket (5) or a heating pipe (6) being provided on the outside of the storage tank I (2), or a heating pipe (6) being provided on the inside of the storage tank I (2), and the jacket (5) or the heating pipe (6) being connected to a steam pipeline (1); The liquid ammonia refrigerant storage tank (4) is connected to the medium inlet (8.1) of the user-end heat exchanger (8) through pipeline I (7); the medium outlet (8.2) of the user-end heat exchanger (8) is connected to the absorption device (10) containing the dissolved ammonia solvent through pipeline II (9); the outlet (10.1) of the absorption device (10) is connected to the booster pump (11) and then connected to the storage tank I (2) through pipeline III (12); A compressor (15) is provided on the pipeline between the storage tank I (2) and the cooling device (3); The cooling device (3) is a shell and tube heat exchanger with cooling water passing through it, and the shell and tube heat exchanger is a heat exchanger with a 33°C cooling water medium passing through it.
2. The production system for preparing refrigerant using surplus steam in polysilicon production according to claim 1, characterized in that: The liquid ammonia refrigerant storage tank (4) is a storage tank for storing high-pressure liquid ammonia.
3. The production system for preparing refrigerant using surplus steam in polysilicon production according to claim 1, characterized in that: The heating tube (6) is a coil (6.1) or a tube array (6.2).
4. The production system for preparing refrigerant using surplus steam in polysilicon production according to claim 1, characterized in that: The exterior of the liquid ammonia refrigerant storage tank (4) is coated with a heat insulation layer (4.1), and a heat insulation sleeve (4.2) is provided on the exterior of the heat insulation layer (4.1).
5. The production system for preparing refrigerant using surplus steam in polysilicon production according to claim 1, characterized in that: The storage tank I (2) is provided with a liquid ammonia supply pipeline (13) and a solvent supply pipeline (14).