Uranium concentration project low-temperature waste heat recovery system and method

Abstract

The invention relates to the technical field of nuclear energy, in particular to a uranium concentration project low-temperature waste heat recovery system and method. By transforming an existing refrigerating system, a water source heat pump and other energy sources are coupled in a multi-mode mode, heat is fixed through cold, stepped absorption is achieved, and the energy utilization rate is increased. The operation control concept of'multi-target control 'is adopted, working modes of all systems are dynamically adjusted, waste heat in low-temperature cooling water is recycled for heating of a factory area in winter, and on the premise that the safety of the process cooling water system is guaranteed, cold and heat matching of an auxiliary system is achieved, and consumption of fossil energy is replaced or reduced. The operation cost and the environmental influence are reduced, and great economic benefits and social benefits are achieved.

Description

Technical Field

[0001] This invention relates to the field of nuclear energy technology, and in particular to a system and method for recovering low-temperature waste heat from uranium enrichment projects. Background Technology

[0002] The main process systems of uranium enrichment projects have strict temperature requirements, necessitating large quantities of cooling water year-round for system cooling. This cooling water temperature is typically below 15°C, with a small supply-return temperature difference. Traditionally, chiller systems are used to ensure a stable supply of cooling water. With the orderly implementation of the national "dual-carbon" policy, uranium enrichment plants are actively seeking more efficient and energy-saving cooling solutions. Various methods have been adopted, including using Yellow River water and open or closed cooling towers for natural cooling, aiming to improve the energy efficiency of the cooling system and reduce electricity consumption and operating costs. However, in actual operation, natural cooling sources such as Yellow River water and open or closed cooling towers are affected by factors such as water quality, geographical location, and climate change, resulting in poor cooling effects and issues such as freezing and cracking, and unstable parameters. In some projects, to ensure that the process cooling water and natural cooling sources do not interfere with each other, separate loops are often set up to achieve complete isolation between the two sides, making the cooling system more complex.

[0003] While the process system requires year-round cooling, there is a significant demand for heat in uranium enrichment projects, especially for heating in production and living areas during winter. Currently, uranium enrichment projects typically use electricity or fossil fuels to meet these heating needs. This "hot and cold furnace" phenomenon not only wastes energy but also greatly increases economic costs.

[0004] Due to the importance and complexity of process cooling water, the mismatch between heat sources and heat sinks, and the low temperature of the waste heat itself, waste heat is not currently recovered and utilized in uranium enrichment projects, nor is there an overall plan for its utilization. Therefore, a solution is urgently needed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a system and method for low-temperature waste heat recovery in uranium enrichment projects. The system requires minimal modification to the existing refrigeration system and can recover waste heat from low-temperature cooling water for use in winter heating of the plant area, which has strong practicality and economic value. To achieve the aforementioned objective, the technical solution of the present invention is implemented as follows: a system and method for low-temperature waste heat recovery in uranium enrichment projects, comprising... The cooling system is connected to the uranium enrichment process system and is used to cool the uranium enrichment process system. The high-temperature heat pump system is connected to the uranium enrichment process system and delivers the heat generated by the uranium enrichment process system to the heat-using terminals for heating. The uranium enrichment process system is connected to a cooling system and a high-temperature heat pump system via connecting pipes, and the cooling system and the high-temperature heat pump system are connected in parallel. A valve assembly is installed at the connection point between the connecting pipe and the uranium enrichment process system, the cooling system and the high-temperature heat pump system, and is used to control the connection or closure between the connecting pipe and the uranium enrichment process system, the cooling system and the high-temperature heat pump system; Temperature monitoring component; the temperature monitoring component is used to monitor the temperature of the uranium enrichment process system, connecting pipelines, cooling system, high-temperature heat pump system and heat-using terminals; The intelligent control device is electrically connected to the valve assembly, temperature monitoring assembly, cooling system, and high-temperature heat pump system. It receives temperature information monitored by the temperature monitoring assembly and adjusts the opening and closing of the valve assembly according to the cooling requirements of the uranium enrichment process system and the temperature of the heat-using terminal. It controls the cooling system and the high-temperature heat pump system to operate independently or in coordination to dissipate the heat generated by the uranium enrichment process system.

[0006] Preferably, the heat-using terminal is the indoor heating demand of the production area and living area during winter in the uranium enrichment process.

[0007] Preferably, the high-temperature heat pump system uses a high-temperature heat pump unit, wherein the evaporation side pipe of the high-temperature heat pump unit is connected to the process cooling water pipe of the uranium enrichment process system for cooling; and the condensation side of the high-temperature heat pump unit is connected to the heat-using terminal. Furthermore, during heating operation, the evaporator side of the high-temperature heat pump unit operates at 11℃ / 13℃ (supply / return water), with an evaporation temperature of 6-9℃; the condenser side of the high-temperature heat pump unit operates at 65℃ / 50℃ (supply / return water), with a condensation temperature of 55-70℃. During cooling operation, the evaporator side of the high-temperature heat pump unit operates at 11℃ / 13℃ (supply / return water), with an evaporation temperature of 6-9℃; the condenser side of the high-temperature heat pump unit operates at 35℃ / 30℃ (supply / return water), with a condensation temperature of 40-45℃.

[0008] Preferably, the cooling system includes an open tower system that provides a cold source for the uranium enrichment process system; the open tower system adopts a cooling tower combined with a large-capacity water tank, and the cooling tower of the open tower system adopts a counter-flow open tower, which is equipped with a variable frequency fan to cool the high-temperature cooling water discharged from the chiller unit or heat pump condenser to 30°C in summer and transitional seasons, and provides chilled water at 8°C / 13°C (supply / return water) in winter.

[0009] The cooling system includes a chiller system that provides a cold source for the uranium enrichment process system; the chiller system is connected to the open tower system, and the chiller system uses a centrifugal or screw chiller.

[0010] Centrifugal or screw chiller unit evaporator side operating conditions: 8℃ / 13℃ (supply / return water), evaporation temperature is 3-6℃; condenser side operating conditions: 35℃ / 30℃ (supply / return water), condensation temperature is 40-45℃; In some projects with better water quality, the chiller unit can directly provide process cooling water. In this case, the unit evaporator side operating conditions: 11℃ / 13℃ (supply / return water), evaporation temperature is 7-10℃; condenser side operating conditions: 35℃ / 30℃ (supply / return water), condensation temperature is 40-45℃.

[0011] Preferably, the cooling system includes a Yellow River water cooling system that provides a cold source for the uranium enrichment process system; the Yellow River water cooling system is connected in parallel with the tower opening system and is also connected to the heat exchange system. In winter, it provides the uranium enrichment process system with chilled water at 8°C / 13°C.

[0012] Preferably, the cooling system includes a heat exchange system; one side of the heat exchange system is connected to both the tower opening system and the Yellow River water cooling system, and the other side is connected to the uranium enrichment process system; the heat exchange system generally adopts a plate heat exchanger, and the plate heat exchanger adopts a wide flow channel design, with the process-side cooling water supply and return water temperatures being 11℃ / 13℃.

[0013] Preferably, the cooling system includes a closed-tower system that provides a cold source for the uranium enrichment process system, providing cooling water at 11°C / 13°C in winter; the process cooling water provided by the closed-tower system circulates in a closed coil, and the cooling side achieves heat exchange through "spray water evaporation + forced ventilation". The spray water forms a water film outside the coil, and the heat of the process medium is carried away by the latent heat of water evaporation. The unevaporated spray water flows back to the water collection tank of the closed-tower system for recycling.

[0014] Preferably, the intelligent control device further includes a controller, a meteorological monitoring and forecasting instrument, temperature and flow sensors arranged in the connecting pipeline; variable frequency fans, variable frequency compressors, and variable frequency water pumps arranged in the cooling system; all valve components are electrically controlled valves; the intelligent control device is equipped with a PLC and AI algorithm, taking the process cooling requirements of the uranium enrichment process system as the control objective, prioritizing the use of a high-temperature heat pump system to absorb the process waste heat generated by the uranium enrichment process system, and controlling the cooling system to participate in process cooling only as one cooling method, and secondly, cascade absorption based on the principle of economy, ensuring the stability of process cooling load and cooling water parameters, and dynamically adjusting the working mode of each system. An energy regulation strategy of "cooling-driven heating," "cascade absorption," and "multi-objective control" is formulated, based on changes in meteorological parameters and heat load.

[0015] Preferably, the method of using the above-mentioned system for low-temperature waste heat recovery in uranium enrichment projects includes the following steps: S1. In winter, the weather monitoring and forecasting instrument and temperature sensor transmit outdoor weather and temperature information to the controller, which then analyzes the weather and temperature information. S2. If the controller determines that the outdoor temperature is greater than 8 degrees, the controller analyzes the indoor temperature and heating demand temperature of the heat-using terminal, adjusts the valve assembly on the connecting pipe, first opens the electric valve at the connecting pipe between the high-temperature heat pump system and the high-temperature heat pump system absorbs the heat generated by the uranium enrichment process system and transfers the absorbed heat to the indoor area of ​​the heat-using terminal. S3. The temperature sensor at the pipeline transmits the temperature information monitored inside the pipeline to the controller. After reading the temperature information inside the pipeline, the controller determines that the high-temperature heat pump system cannot completely absorb the heat generated by the uranium enrichment process system, and then starts the heat exchange system, tower opening system and / or chiller system to supplement and absorb the heat generated by the uranium enrichment process system. S4. If the controller determines that the outdoor temperature is within the range of 1-8 degrees Celsius and the heat generated by the uranium enrichment process system cannot be absorbed by the high-temperature heat pump system, the controller will shut down the chiller system and start the heat exchange system and tower opening system to supplement and absorb the heat generated by the uranium enrichment process system. If the controller determines that the outdoor temperature is less than 1 degree and the heat generated by the uranium enrichment process system cannot be absorbed by the high-temperature heat pump system, the controller shuts down the chiller system and the fans of the tower opening system. The high-temperature water that has absorbed the waste heat from the heat exchange system no longer goes up to the tower, and only the large water pool at the bottom of the tower opening system provides cooling. When the water pool cannot absorb the remaining waste heat, the Yellow River water cooling system is turned on to supplement the absorption. S5. After analysis, if the controller determines that the outdoor temperature is less than 8 degrees and the heat generated by the uranium enrichment process system cannot be absorbed by the high-temperature heat pump system, and the site is not equipped with a Yellow River water cooling system and a heat exchange system, the controller will first turn on the high-temperature heat pump system and then turn on the closed tower system to jointly absorb the heat generated by the uranium enrichment process system. If the controller determines that the outdoor temperature is less than 1 degree, and the heat generated by the uranium enrichment process system cannot be absorbed by the high-temperature heat pump system, and the site is not equipped with a Yellow River water cooling system and heat exchange system, the controller will first turn on the high-temperature heat pump system, and then turn on the chiller system and tower opening system to absorb the heat generated by the uranium enrichment process system together. S6, during the process of the high-temperature heat pump system absorbing the heat generated by the uranium enrichment process system, the controller adjusts the operation of the high-temperature heat pump unit by frequency conversion based on the difference between the theoretical and measured values ​​of the supply and return water temperatures, and adjusts the operating power of the frequency conversion fan, frequency conversion compressor and frequency conversion water pump in the cooling system to achieve multi-mode coupled operation and ensure that the supply and return water temperatures of the pipeline network reach the set values.

[0016] The system adopts a hot water temperature regulation method, which only changes the supply and return water temperatures of the heating system during the heating period, while keeping the circulating water volume constant. The outdoor temperature sensor collects the outdoor temperature in real time and transmits it to the controller. The controller determines the theoretical supply and return water temperatures based on the quality-regulated heating curve and the current outdoor temperature. At the same time, the temperature collector in the secondary pipe network returns the real-time supply and return water temperature measurements. The process cooling load absorbed by the evaporator side of the heat pump unit changes with the user's heat load. The operation and regulation of the process cooling water (evaporator side of the heat pump unit) must ensure stable process operation. The evaporator-side cooling water system uses a flow rate regulation method, and the supply and return water temperatures must be kept constant. At this point, the supply and return water temperatures are the target parameters of the control system. As the user's heat load changes on the condenser side, the heat pump unit operates at a variable frequency, and the operating parameters on the evaporator side will also change accordingly. By adjusting the electric regulating valves on the evaporator side of the heat pump unit, it is ensured that the system adapts to changes in heat load while maintaining constant supply and return water temperatures for the process cooling water.

[0017] The beneficial effects of this invention are reflected in: Compared with existing uranium enrichment projects, the system and method for low-temperature waste heat recovery in uranium enrichment projects provided by this invention are based on an energy comprehensive algorithm. This algorithm dynamically adjusts the operating modes of each system and, according to energy topology, recovers waste heat from the low-temperature cooling water for winter heating in the plant area, while eliminating the impact of waste heat utilization on process safety. This achieves cooling and heating matching of auxiliary systems and improves energy utilization efficiency. Furthermore, this system requires minimal modification to existing refrigeration systems, making it highly practical and economically valuable. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the low-temperature waste heat recovery system for uranium enrichment engineering according to the present invention; Figure 2 This is a system schematic diagram of the parallel scheme for low-temperature waste heat recovery in uranium enrichment engineering according to the present invention; Figure 3 This is a diagram showing the waste heat cascade utilization sequence of the present invention; Figure 4 This is a schematic diagram of the condenser-side control principle of the high-temperature heat pump unit of the present invention; Figure 5 This is a schematic diagram of the evaporator-side control principle of the high-temperature heat pump unit of the present invention; Figure 6 This is a schematic diagram of the cryogenic waste heat recovery system for uranium enrichment engineering in Embodiment 1 of the present invention; Figure 7 This is a schematic diagram of the low-temperature waste heat recovery system for uranium enrichment engineering in Embodiment 2 of the present invention.

[0019] Figure labels and descriptions: 1. Heat exchange system; 11. Heat exchanger; 12. Electric regulating valve six; 2. High-temperature heat pump system; 3. Closed tower system; 4. Open tower system; 5. Yellow River water cooling system; 6. Chiller system; 21. High-temperature heat pump unit; 22. Electric regulating valve seven; 23. Electric regulating valve one; 24. Electric regulating valve ten; 31. Closed cooling tower; 32. Electric regulating valve eleven; 41. Open cooling tower; 42. Open cooling tower water tank; 43. Electric regulating valve twelve; 44. Electric regulating valve two; 45. Circulating water pump; 46. Electric regulating valve three; 47. Electric regulating valve four; 51. Yellow River heat exchanger; 52. Electric regulating valve five; 61. Refrigeration unit; 62. Electric regulating valve eight; 63. Electric regulating valve nine. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] like Figure 1-5 As shown, this invention provides a system and method for low-temperature waste heat recovery in uranium enrichment projects. Utilizing the operational control concepts of "heat recovery based on cooling," tiered consumption, and multi-objective control, it achieves heat matching for auxiliary systems through a multi-mode coupling of high-temperature heat pumps and other energy sources, while ensuring the safety of the process cooling water system. This replaces or reduces the consumption of fossil fuels, lowering operating costs and environmental impact, and contributing to the achievement of "dual-carbon" goals. Specific implementation details are as follows: Example 1 This embodiment applies to uranium enrichment projects in Lanzhou, Gansu Province. The current process cooling system uses a chiller unit and an open cooling tower to dissipate waste heat during the summer. In winter, a combination of chiller units, Yellow River water, open tower, and plate heat exchangers is used to dissipate waste heat from the process.

[0022] Low-temperature waste heat recovery system, such as Figure 6 As shown. High-temperature heat pump system 2 is installed in parallel with heat exchange system 1. The evaporator-side piping of the heat pump unit is connected to the process cooling water piping. During heating operation, the evaporator-side supply / return water temperature is 11℃ / 13℃, the condenser-side supply water temperature is a maximum of 65℃, and the supply / return water temperature difference is 15℃. Depending on the air temperature and the Yellow River water temperature, this system can achieve the following three modes: ① Refrigeration unit + heat pump coupled operation At this time, the water temperatures of both the Yellow River water cooling system 5 and the open tower system 4 do not reach the required 8℃ / 13℃. Electric regulating valves 1-23, 2-44, 3-46, 4-47, and 5-52 are closed, while the remaining electric regulating valves are open. Based on the heat load, the openings of electric regulating valves 6-12 and 7-22 are adjusted on the primary side of heat exchange system 1 to prioritize the absorption of process cooling load through heat pump unit 21, thus meeting the heat requirements. The remaining waste heat from the process enters heat exchange system 1 and is absorbed by refrigeration unit 61.

[0023] On the secondary side of heat exchange system 1, chilled water at 8°C is generated on the evaporator side of refrigeration unit 61 and enters heat exchange system 1. After absorbing the waste heat from the process, the water temperature rises to 13°C. High-temperature cooling water at 35°C is generated on the condenser side and enters the open tower system 4. It is cooled to 30°C through measures such as frequency conversion of fans and is then recycled.

[0024] ②Coupling operation of tower opening and heat pump Based on local meteorological conditions, the water temperatures of both the Yellow River water cooling system 5 and the open tower system 4 can reach the required 8℃ / 13℃, and there is no risk of the cooling tower freezing. The open tower system 4 has lower energy consumption than the Yellow River water cooling system 5; therefore, based on economic principles, the coupled operation mode of heat pump unit 21 and open tower system 4 is activated.

[0025] Close electric regulating valve 1 (23), electric regulating valve 2 (44), electric regulating valve 5 (52), electric regulating valve 8 (62), and electric regulating valve 9 (63), and open all other electric regulating valves.

[0026] Based on the magnitude of the heat load, the opening degrees of electric regulating valves 12 and 22 are adjusted on the primary side of heat exchange system 1 to prioritize the absorption of process cooling load through heat pump unit 21, thereby meeting the heat requirements. The remaining process waste heat enters heat exchange system 1 and is absorbed by open cooling tower 41.

[0027] On the secondary side of heat exchange system 1, the chilled water at 8°C generated by open cooling tower 41 enters heat exchange system 1 through the action of circulating water pump 45. After absorbing the waste heat from the process, the water is heated to 13°C and then goes back up the tower to dissipate heat.

[0028] ③ Open tower + Yellow River water + heat pump coupled operation Based on local meteorological conditions, the water temperatures of both the Yellow River water cooling system 5 and the open cooling tower system 4 can reach the required 8℃ / 13℃, but there is a risk of the cooling tower freezing. Therefore, based on economic principles, the coupled operation mode of heat pump unit 21 + open cooling tower 41 + Yellow River water cooling system 5 is activated.

[0029] Close electric regulating valve 123, electric regulating valve 1243, electric regulating valve 862, and electric regulating valve 963. Open all other electric regulating valves on the pipeline. Based on the heat load, adjust the opening of electric regulating valve 612 and electric regulating valve 722 on the primary side of heat exchange system 1, prioritizing the absorption of process cooling load through heat pump unit 21 to meet heat requirements.

[0030] The remaining waste heat from the process enters heat exchange system 1 and is absorbed by the Yellow River water cooling system 5 and the open tower system 4. On the secondary side of heat exchange system 1, the 8°C chilled water generated by the open cooling tower water tank 42 and the Yellow River heat exchanger 51 enters heat exchange system 1, absorbs the waste heat from the process, and is heated to 13°C before returning to the water tank 42 and the Yellow River heat exchanger 51 to dissipate heat.

[0031] In this embodiment, the quality adjustment table 1 on the heating user side is shown according to temperature changes: Table 1 User-side quality control data table for Example 1

[0032] This embodiment has been verified through continuous operation throughout the 2024-2025 heating season. The process cooling system is stable, the heating effect is good, and the economic cost is reduced by 66% compared with coal-fired boiler heating.

[0033] In addition, when the heat user demand is 0 and the water temperature of the Yellow River water cooling system 5 and the open tower system 4 cannot reach 8℃ / 13℃, the high-temperature heat pump unit can operate under cooling conditions to absorb the process cooling load.

[0034] At this point, the following electric regulating valves should be closed: electric regulating valve 612, electric regulating valve 1024, electric regulating valve 52, electric regulating valve 862, electric regulating valve 244, and electric regulating valve 963. All other electric regulating valves on the pipeline should be opened.

[0035] The high-temperature heat pump unit 21 absorbs waste heat from the process on its evaporation side, producing chilled water at 11°C, which is then recycled back into the process equipment. The condenser side produces high-temperature cooling water at 35°C, which enters the open tower system 4 and is cooled to 30°C through measures such as frequency converters and fans, before being recycled. This model not only reduces the operating time of the uranium enrichment chiller units, extending their service life, but also reduces the chiller unit standby rate, thereby reducing initial investment.

[0036] Example 2: This embodiment is applicable to uranium enrichment projects in Hanzhong, Shaanxi Province. The current process cooling system uses a water chiller unit and an open cooling tower to dissipate process waste heat in summer and a closed cooling tower to dissipate process waste heat in winter.

[0037] Low-temperature waste heat recovery system, such as Figure 7As shown, the high-temperature heat pump system 2 and the closed-tower system 3 are installed in parallel.

[0038] The evaporator-side piping of the heat pump unit is connected to the process cooling water piping. During heating operation, the evaporator-side supply / return water temperatures are 11℃ / 13℃, and the maximum condenser-side supply water temperature is 65℃, with a supply / return water temperature difference of 15℃. Depending on the ambient temperature, the system can operate in the following two modes: ① Refrigeration unit + heat pump coupled operation At this time, the water temperature of the closed cooling tower system 3 does not reach the requirement of 11℃ / 13℃. The electric regulating valve 1132 is closed, and the other electric regulating valves are opened.

[0039] Based on the heat load, the opening degrees of electric regulating valves 62 (eight) and 22 (seven) are adjusted to prioritize the absorption of process cooling load through heat pump unit 21, thus meeting the heating requirements. Remaining process waste heat is absorbed by refrigeration unit 61. The evaporator side of refrigeration unit 61 absorbs the process waste heat, producing 11°C chilled water, which is then recycled back into the process equipment. The condenser side produces 35°C high-temperature cooling water, which enters the open tower system 4 and is cooled to 30°C through measures such as frequency converters and fans, before being recycled.

[0040] ② Closed-tower + heat pump coupled operation Based on local meteorological conditions, the water temperature in the closed-loop cooling tower system 3 can reach the required 11℃ / 13℃. Electric regulating valve 62 is closed, while the remaining electric regulating valves are open. The openings of electric regulating valves 32 and 22 are adjusted according to the heat load, prioritizing the absorption of process cooling load by the heat pump unit 21 to meet heat requirements. Remaining process waste heat is absorbed by the closed-loop cooling tower 31. High-temperature process cooling water enters the closed-loop cooling tower system 3, is cooled to 11℃ using methods such as frequency converter fans, and is then recycled back into the process equipment.

[0041] In this embodiment, the quality adjustment table 2 for the heating user side is shown according to temperature changes: Table 2 User-side quality adjustment data table for Example 2

[0042] After implementation of this embodiment, the economic cost of heating can be reduced by 70% compared to heating with a coal-fired boiler.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A system for low temperature waste heat recovery in uranium enrichment engineering, characterized in that, include: The cooling system is connected to the uranium enrichment process system and is used to cool the uranium enrichment process system. The high-temperature heat pump system (2) is connected to the uranium enrichment process system and delivers the heat generated by the uranium enrichment process system to the heat-using terminal for heating. The uranium enrichment process system is connected to the cooling system and the high-temperature heat pump system (2) respectively through the connecting pipes, and the cooling system and the high-temperature heat pump system (2) are connected in parallel. A valve assembly is installed at the connection point between the connecting pipe and the uranium enrichment process system, the cooling system and the high-temperature heat pump system (2), and is used to control the connection or closure between the connecting pipe and the uranium enrichment process system, the cooling system and the high-temperature heat pump system (2); Temperature monitoring component; the temperature monitoring component is used to monitor the temperature of the uranium enrichment process system, connecting pipelines, cooling system, high-temperature heat pump system (2) and heat-using terminals; The intelligent control device is electrically connected to the valve assembly, temperature monitoring assembly, cooling system and high-temperature heat pump system (2). It receives temperature information monitored by the temperature monitoring assembly and adjusts the opening and closing of the valve assembly according to the cooling requirements of the uranium enrichment process system and the temperature of the heat-using terminal. It controls the cooling system and the high-temperature heat pump system (2) to operate independently or in coordination to absorb the heat generated by the uranium enrichment process system.

2. The system for recovering low-temperature waste heat in uranium enrichment engineering according to claim 1, characterized in that, The heat-using terminal refers to the indoor heating needs of the production and living areas during winter in the uranium enrichment process.

3. The system for low temperature waste heat recovery in uranium enrichment engineering according to claim 2, characterized in that, The high-temperature heat pump system (2) adopts a high-temperature heat pump unit. The evaporation side pipe of the high-temperature heat pump unit is connected to the process cooling water pipe of the uranium enrichment process system for cooling. The condensation side of the high-temperature heat pump unit is connected to the heat-using terminal.

4. The system for recovering low-temperature waste heat in uranium enrichment engineering according to claim 3, characterized in that, The cooling system includes an open tower system (4) that provides a cold source for the uranium enrichment process system; the open tower system (4) adopts a cooling tower combined with a large-capacity water tank, and the cooling tower of the open tower system (4) adopts a counter-flow open tower, which is equipped with a variable frequency fan.

5. The system for low temperature waste heat recovery in uranium enrichment engineering according to claim 4, characterized in that, The cooling system includes a chiller system (6) that provides a cold source for the uranium enrichment process system; the chiller system (6) is connected to the open tower system (4), and the chiller system (6) adopts a centrifugal or screw chiller.

6. The system for low temperature waste heat recovery in uranium enrichment engineering according to claim 4, characterized in that, The cooling system includes a Yellow River water cooling system (5) that provides a cold source for the uranium enrichment process system; the Yellow River water cooling system (5) is connected in parallel with the tower opening system (4) and is connected to the heat exchange system (1).

7. A system for cryogenic waste heat recovery in uranium enrichment engineering according to claim 5 or 6, characterized in that, The cooling system includes a heat exchange system (1); one side of the heat exchange system (1) is connected to the tower opening system (4) and the Yellow River water cooling system (5), and the other side is connected to the uranium enrichment process system.

8. A system for cryogenic waste heat recovery in uranium enrichment engineering according to claim 3 or 4 or 5, characterized in that, The cooling system comprises a closed tower system (3) providing a cold source for the uranium enrichment process system; the closed tower system (3) is communicated with the uranium enrichment process system, the process cooling water provided by the closed tower system (3) for the uranium enrichment process system circulates in the closed coil pipe, the outside of the closed coil pipe is provided with a spray water evaporation and forced ventilation for heat exchange, the spray water forms a water film outside the coil pipe, and the evaporated spray water carries away the heat of the process medium, and the unevaporated spray water flows back to the water collecting tank of the closed tower system (3) for recycling.

9. The system and method of Claim 1, wherein, The intelligent control device further comprises a controller, a weather monitoring and forecasting instrument, temperature and flow sensors arranged in the communication pipeline, a variable frequency fan, a variable frequency compressor and a variable frequency water pump arranged in the cooling system, and the valve assembly is an electric control valve; the intelligent control device is provided with a PLC and an AI algorithm, the process cooling demand of the uranium enrichment process system is taken as a control target, the process waste heat generated by the uranium enrichment process system is preferentially consumed by the high-temperature heat pump system (2), and the cooling system is only used as one of the cooling modes to participate in the process cooling, and the process cooling load and the cooling water parameters are stabilized, and the working modes of the systems are dynamically adjusted.

10. A method of using a system for low temperature waste heat recovery in uranium enrichment engineering according to any of claims 1-9, characterized in that, The method comprises the following steps: S1, in winter, the weather information and temperature information outside the room are transmitted to the controller by the weather monitoring and forecasting instrument and the temperature sensor, and the controller analyzes the weather information and temperature information; S2, if the controller determines that the outdoor temperature is greater than 8 degrees, the controller analyzes the indoor temperature of the heat utilization terminal and the heating demand temperature, adjusts the valve assembly on the communication pipeline, and first opens the electric valve at the communication pipeline of the high-temperature heat pump system (2), the high-temperature heat pump system (2) consumes the heat generated by the uranium enrichment process system, and transmits the absorbed heat to the indoor heat utilization terminal; S3, the temperature information in the pipeline monitored by the temperature sensor in the pipeline is transmitted to the controller, the controller reads the temperature information in the pipeline, determines that the high-temperature heat pump system (2) cannot completely consume the heat generated by the uranium enrichment process system, and then opens the heat exchange system (1), the open tower system (4) and / or the water chiller system (6) to supplement the consumption of the heat generated by the uranium enrichment process system; S4, if the controller determines that the outdoor temperature is in the range of 1-8 degrees, and the heat generated by the uranium enrichment process system cannot be consumed by the high-temperature heat pump system (2), the controller closes the water chiller system (6), and opens the heat exchange system (1) and the open tower system (4) to supplement the consumption of the heat generated by the uranium enrichment process system; if the controller determines that the outdoor temperature is less than 1 degree, and the heat generated by the uranium enrichment process system cannot be consumed by the high-temperature heat pump system (2), the controller closes the water chiller system (6) and the fan of the open tower system (4), the high-temperature water absorbing the process waste heat from the heat exchange system (1) no longer goes up the tower, and only the large water pool at the lower part of the open tower system (4) provides cold; when the water pool cannot consume the remaining waste heat, the Yellow River water cooling system (5) is opened for supplemental consumption. S5, after analysis, if the controller determines that the outdoor temperature is in the range of 1-8 degrees, and the heat generated by the uranium enrichment process system cannot be absorbed by the high-temperature heat pump system (2), and the site is not equipped with the Yellow River water cooling system (6) and the heat exchange system (1), the controller first starts the high-temperature heat pump system (2), and then starts the closed tower system (3) to jointly absorb the heat generated by the uranium enrichment process system; If the controller determines that the outdoor temperature is less than 1 degree, and the heat generated by the uranium enrichment process system cannot be absorbed by the high-temperature heat pump system (2), and the site is not equipped with the Yellow River water cooling system (6) and the heat exchange system (1), the controller first starts the high-temperature heat pump system (2), and then starts the water chiller system (6) and the open tower system (4) to jointly absorb the heat generated by the uranium enrichment process system; S6, in the process of absorbing the heat generated by the uranium enrichment process system by the high-temperature heat pump system (2), the controller adjusts the operation of the high-temperature heat pump unit according to the difference between the theoretical and measured values of the supply and return water temperatures, and adjusts the operating power of the variable frequency fan, variable frequency compressor and variable frequency water pump in the cooling system, realizes multi-mode coupled operation, and ensures that the supply and return water temperatures of the pipe network reach the set value.

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