A heat exchange system and control method for precooling carbon dioxide using liquid ammonia

Abstract

The invention relates to a heat exchange system for precooling carbon dioxide with liquid ammonia and a control method. The heat exchange system for precooling carbon dioxide with liquid ammonia comprises a carbon dioxide precooling mechanism, a liquid ammonia heat exchange mechanism and a liquid ammonia storage mechanism; a first liquid ammonia input end of the carbon dioxide precooling mechanism is connected to a first liquid ammonia output end of the liquid ammonia heat exchange mechanism, a second liquid ammonia input end of the carbon dioxide precooling mechanism and a liquid ammonia output end of the carbon dioxide precooling mechanism are connected to the first liquid ammonia input end of the liquid ammonia heat exchange mechanism, the first liquid ammonia input end of the liquid ammonia heat exchange mechanism is connected to the liquid ammonia output end of the carbon dioxide precooling mechanism, and the second liquid ammonia input end of the liquid ammonia heat exchange mechanism is connected to the liquid ammonia output end of the liquid ammonia storage mechanism. By reasonably recycling the cold energy of liquid ammonia, energy consumption is effectively reduced, energy utilization efficiency is improved, and efficient cooling and liquefaction of carbon dioxide are achieved through multi-stage heat exchange, providing a more efficient and energy-saving solution for the decarbonization process of a power plant.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchange systems, and in particular to a heat exchange system for precooling carbon dioxide with liquid ammonia and a control method thereof. Background Art

[0002] At present, traditional power plant decarbonization technologies mainly rely on the combustion of fossil fuels and conventional cooling systems. However, these methods have significant disadvantages in terms of energy consumption and efficiency. Especially in the process of carbon capture and storage, conventional cooling technology usually relies on high-temperature and high-pressure cooling media, which not only increases energy consumption, but also leads to low overall energy utilization efficiency. In addition, the traditional decarbonization process has high requirements for temperature and pressure, resulting in additional equipment investment and operating costs, which makes it difficult to meet the needs of high efficiency and low carbon emissions. Summary of the invention

[0003] In order to solve the problems of high energy consumption and low efficiency in traditional power plant decarbonization technology, the present application provides a heat exchange system and a control method for precooling carbon dioxide with liquid ammonia.

[0004] A heat exchange system for precooling carbon dioxide with liquid ammonia, the heat exchange system for precooling carbon dioxide with liquid ammonia comprising a carbon dioxide precooling mechanism, a liquid ammonia heat exchange mechanism and a liquid ammonia storage mechanism;

[0005] The carbon dioxide input end of the carbon dioxide precooling mechanism is used to receive the analyzed carbon dioxide, the first liquid ammonia input end of the carbon dioxide precooling mechanism is connected to the first liquid ammonia output end of the liquid ammonia heat exchange mechanism to receive the first-stage heat exchange liquid ammonia, the second liquid ammonia input end of the carbon dioxide precooling mechanism is used to receive the second-stage heat exchange liquid ammonia, the liquid ammonia output end of the carbon dioxide precooling mechanism is connected to the first liquid ammonia input end of the liquid ammonia heat exchange mechanism, the analyzed carbon dioxide is sequentially heat exchanged with the first-stage heat exchange liquid ammonia and the second-stage heat exchange liquid ammonia to generate and output the corresponding liquid carbon dioxide, the first-stage heat exchange liquid ammonia generates the corresponding ammonia to be burned after the heat exchange, and the second-stage heat exchange liquid ammonia generates the corresponding liquid ammonia to be cooled after the heat exchange;

[0006] The first liquid ammonia input end of the liquid ammonia heat exchange mechanism is connected to the liquid ammonia output end of the carbon dioxide precooling mechanism for receiving the liquid ammonia to be cooled. The second liquid ammonia input end of the liquid ammonia heat exchange mechanism is connected to the liquid ammonia output end of the liquid ammonia storage mechanism for receiving cold-keeping liquid ammonia. After the liquid ammonia to be cooled is heat-exchanged with the cold-keeping liquid ammonia, the liquid ammonia to be cooled is converted into cooled liquid ammonia and output to the liquid ammonia storage mechanism through the second liquid ammonia output end of the liquid ammonia heat exchange mechanism. The cold-keeping liquid ammonia is converted into primary heat exchange liquid ammonia and output to the carbon dioxide precooling mechanism through the first liquid ammonia output end of the liquid ammonia heat exchange mechanism.

[0007] By adopting the above technical scheme, in order to solve the problems of high energy consumption and low efficiency in the decarbonization technology of traditional power plants, the present invention adopts liquid ammonia as a refrigerant for precooling and storing carbon dioxide, thereby improving energy utilization. Specifically, the heat exchange system for precooling carbon dioxide with liquid ammonia realizes efficient cooling and liquefaction of carbon dioxide through a two-stage heat exchange process. In this system, the analyzed carbon dioxide first passes through the carbon dioxide precooling mechanism, and exchanges heat with the primary heat exchange liquid ammonia and the secondary heat exchange liquid ammonia in sequence to reduce the temperature of carbon dioxide and finally convert it into liquid carbon dioxide. During the heat exchange process, the primary heat exchange liquid ammonia and the secondary heat exchange liquid ammonia are respectively heat exchanged to generate ammonia to be burned and liquid ammonia to be cooled. The liquid ammonia to be cooled is further heat exchanged with the cold liquid ammonia through the liquid ammonia heat exchange mechanism, converted into low-temperature cooling liquid ammonia, and then stored in the liquid ammonia storage mechanism; at the same time, the cold liquid ammonia is restored to the primary heat exchange liquid ammonia after heat exchange, and is re-supplied to the carbon dioxide precooling mechanism for heat exchange. The system effectively reduces energy consumption and improves energy utilization efficiency by rationally recycling the cold energy of liquid ammonia, and achieves efficient cooling and liquefaction of carbon dioxide through multi-stage heat exchange, providing a more efficient and energy-saving solution for the decarbonization process of power plants.

[0008] Preferably, the carbon dioxide precooling mechanism comprises a primary precooler, a secondary precooler and a liquefaction unit;

[0009] The carbon dioxide input end of the primary precooler is used to receive the analyzed carbon dioxide, the liquid ammonia input end of the primary precooler is connected to the first liquid ammonia output end of the liquid ammonia heat exchange mechanism to receive the primary heat exchange liquid ammonia, the carbon dioxide output end of the primary precooler is connected to the carbon dioxide input end of the secondary precooler, so that the secondary precooler receives the carbon dioxide after the primary heat exchange, and the ammonia output end of the primary precooler is used to output the ammonia to be burned;

[0010] The liquid ammonia input end of the liquefaction unit is used to receive the secondary heat exchange liquid ammonia, the liquid ammonia input end of the secondary precooler is connected to the liquid ammonia output end of the liquefaction unit, so that the secondary precooler receives the secondary heat exchange liquid ammonia, and the carbon dioxide output end of the secondary precooler is connected to the carbon dioxide input end of the liquefaction unit, so that the liquefaction unit liquefies the carbon dioxide after the secondary heat exchange.

[0011] By adopting the above technical solution, the configuration of the primary precooler, the secondary precooler and the liquefaction unit in the carbon dioxide precooling mechanism can effectively cool the carbon dioxide step by step at different heat exchange stages, and further liquefy the carbon dioxide through the liquefaction unit. This design not only improves the liquefaction efficiency of carbon dioxide, but also can accurately control the temperature and pressure at each stage, ensuring that the carbon dioxide is always in the best state during the liquefaction process, and reducing the energy consumption and operation difficulty of carbon dioxide liquefaction.

[0012] Preferably, the liquefaction unit includes a carbon dioxide economizer and a carbon dioxide cryogenic refrigerator, the liquid ammonia input end of the carbon dioxide economizer and the liquid ammonia input end of the carbon dioxide cryogenic refrigerator are both used to receive secondary heat exchange liquid ammonia, the liquid ammonia output end of the carbon dioxide economizer and the liquid ammonia output end of the carbon dioxide cryogenic refrigerator are both connected to the liquid ammonia input end of the secondary precooler, the carbon dioxide input end of the carbon dioxide economizer is connected to the carbon dioxide output end of the secondary precooler, the carbon dioxide output end of the carbon dioxide economizer is connected to the carbon dioxide input end of the carbon dioxide cryogenic refrigerator, after successively passing through the cooling effect of the secondary heat exchange liquid ammonia in the carbon dioxide economizer and the carbon dioxide cryogenic refrigerator, the carbon dioxide after the secondary heat exchange is converted into liquid carbon dioxide, and the carbon dioxide output end of the carbon dioxide cryogenic refrigerator is used to output the liquid carbon dioxide.

[0013] By adopting the above technical solution, the energy efficiency of liquid carbon dioxide can be effectively improved. The series configuration of the carbon dioxide economizer and the cryocooler reduces the use of cooling medium and optimizes the heat exchange process through staged cooling and energy recovery, thereby reducing liquid ammonia consumption and energy loss, and improving the overall energy efficiency of the system.

[0014] Preferably, the liquid ammonia input end of the carbon dioxide economizer is connected to a first expansion valve, and the liquid ammonia input end of the carbon dioxide cryogenic refrigerator is connected to a second expansion valve. Both the first expansion valve and the second expansion valve reduce the temperature of the secondary heat exchange liquid ammonia through expansion throttling, thereby allowing the secondary heat exchange liquid ammonia temperature to cool the carbon dioxide after the secondary heat exchange.

[0015] By adopting the above technical solution, the secondary heat exchange liquid ammonia can be cooled by expansion throttling before entering the carbon dioxide economizer and cryogenic refrigerator, thereby effectively reducing the temperature of the liquid ammonia, so that it can better provide cold energy for the liquefaction process of carbon dioxide. This throttling and cooling method improves the cooling efficiency of carbon dioxide and ensures that the entire process is carried out on the basis of energy saving.

[0016] Preferably, the liquid ammonia heat exchange mechanism comprises a water cooler, a primary ammonia heat exchanger and a secondary ammonia heat exchanger;

[0017] The liquid ammonia input end of the water cooler is connected to the liquid ammonia output end of the carbon dioxide precooling mechanism, the liquid ammonia output end of the water cooler is connected to the first liquid ammonia input end of the primary ammonia heat exchanger, the first liquid ammonia output end of the primary ammonia heat exchanger is connected to the first liquid ammonia input end of the secondary ammonia heat exchanger, and the first liquid ammonia output end of the secondary ammonia heat exchanger is connected to the liquid ammonia input end of the liquid ammonia storage mechanism;

[0018] The liquid ammonia output end of the liquid ammonia storage mechanism is connected to the second liquid ammonia input end of the secondary ammonia heat exchanger, the second liquid ammonia output end of the secondary ammonia heat exchanger is connected to the second liquid ammonia input end of the primary ammonia heat exchanger, and the second liquid ammonia output end of the primary ammonia heat exchanger is connected to the first liquid ammonia input end of the carbon dioxide precooling mechanism;

[0019] Wherein, the water cooler is connected to a water cooling pipe, in which cooling water flows, and cold liquid ammonia output from the liquid ammonia storage mechanism flows through the primary ammonia heat exchanger and the secondary ammonia heat exchanger. Under the cooling effect of the cooling water and the cold liquid ammonia in sequence, the liquid ammonia to be cooled is converted into cooled liquid ammonia, and is transported to the liquid ammonia storage mechanism through the first liquid ammonia output end of the secondary ammonia heat exchanger for storage and cold preservation.

[0020] By adopting the above technical solution, the cooling effect of liquid ammonia can be effectively improved. The water cooler is combined with the water cooling pipe to reduce the temperature of liquid ammonia by using the efficient heat exchange capacity of cooling water; the primary and secondary ammonia heat exchangers further cool down through multi-stage heat exchange to ensure that the liquid ammonia to be cooled can be fully cooled and finally stored as cold liquid ammonia. This multi-stage cooling method reduces the dependence on external cooling media, while improving the cooling efficiency and storage safety of liquid ammonia.

[0021] Preferably, the liquid ammonia storage mechanism comprises a subcooler and a liquid ammonia storage tank, the liquid ammonia input end of the subcooler is connected to the second liquid ammonia output end of the liquid ammonia heat exchange mechanism, the liquid ammonia output end of the subcooler is connected to the liquid ammonia input end of the liquid ammonia storage tank, and the liquid ammonia output end of the liquid ammonia storage tank is connected to the second liquid ammonia input end of the liquid ammonia heat exchange mechanism;

[0022] The supercooler is connected to a first refrigeration pipeline, and the refrigerant flowing in the first refrigeration pipeline is used to perform primary refrigeration insulation on the cooled liquid ammonia. The liquid ammonia storage tank is connected to a second refrigeration pipeline, and the second refrigeration pipeline is provided with flowing refrigerant to perform secondary refrigeration insulation on the cooled liquid ammonia after primary refrigeration insulation, and then convert it into refrigerated liquid ammonia, and output the refrigerated liquid ammonia through the liquid ammonia output end of the liquid ammonia storage tank.

[0023] By adopting the above technical solution, it is possible to ensure that the liquid ammonia is kept at a low temperature and avoid temperature fluctuations during storage. The supercooler ensures that the cooled liquid ammonia can maintain the required temperature range through the primary cold preservation and the secondary cold preservation of the liquid ammonia storage tank, and minimizes heat exchange during storage, ensuring that the liquid ammonia is always at a suitable temperature during storage, thereby improving storage stability and safety.

[0024] Preferably, a liquid ammonia discharge pipeline liquid level regulating valve group is provided between the liquid ammonia output end of the liquid ammonia storage tank and the second liquid ammonia input end of the liquid ammonia heat exchange mechanism.

[0025] By adopting the above technical solution, accurate liquid level control can be achieved during the liquid ammonia storage process. By adjusting the liquid level, a stable supply of liquid ammonia and an appropriate coolant flow rate can be ensured, and uneven cooling or energy waste caused by too low or too high liquid level can be avoided, thereby improving the safety and reliability of the system.

[0026] Preferably, a liquid ammonia delivery pump is provided between the liquid ammonia discharge pipeline liquid level regulating valve group and the second liquid ammonia input end of the liquid ammonia heat exchange mechanism.

[0027] By adopting the above technical solution, the stable delivery of liquid ammonia can be ensured and the accuracy of flow regulation can be improved. The liquid ammonia delivery pump can adjust the flow rate of liquid ammonia during storage and heat exchange, ensuring the smooth flow of liquid ammonia in each link, further improving the heat exchange efficiency and reducing energy consumption.

[0028] A control method for a heat exchange system for precooling carbon dioxide using liquid ammonia, which is applied to a heat exchange system for precooling carbon dioxide using liquid ammonia, and the control method comprises:

[0029] Acquire a heat exchange path of interest, and determine a component of interest and an association relationship between each component of interest according to the heat exchange path of interest;

[0030] Determine an expected temperature interval of the component of interest, wherein the expected temperature interval includes an expected fluid input temperature interval and an expected fluid output temperature interval;

[0031] Acquiring fluid temperature input and output data of the component of interest;

[0032] Determine whether the temperature input and output data fall within the corresponding expected temperature range, and if so, add or maintain the corresponding visualization feature in the constructed visualization platform;

[0033] If not, determine that the component of interest is the target component, determine the fluid temperature input and output data and the expected temperature range as target data, and determine the associated component corresponding to the target component based on the association relationship, call the associated data of the associated component, determine whether the associated components are both target components based on the associated data, determine the corresponding flow control parameters based on the target data, and the flow control parameters are used to adjust the fluid speed in the component of interest and the target component.

[0034] By adopting the above technical solution, the system operation status can be monitored in real time by accurately obtaining the temperature input and output data of the components of interest and the expected temperature range of the fluid, ensuring that the temperature is controlled within a reasonable range. When the temperature deviates from the expected value, the relevant components can be discovered and adjusted in time to avoid system performance degradation or energy waste due to abnormal temperature, thereby improving the stability and operation efficiency of the system. At the same time, the matching of the expected temperature range of the associated components and the fluid temperature data can ensure that the temperature remains balanced during the collaborative heat exchange process of multiple components, further improving the response speed and reliability of the overall heat exchange system.

[0035] Preferably, the steps of calling the associated data of the associated components, determining whether the associated components are the same target components according to the associated data, and determining the corresponding flow control parameters according to the target data include:

[0036] Determine a corresponding first deviation value according to the fluid temperature input and output data and the expected temperature range in the target data, and determine a flow control parameter of the target component according to the first deviation value;

[0037] Calling the associated data of the associated component, the associated data including the expected temperature range of the associated component, the fluid temperature input and output data of the associated component, and component attribute data;

[0038] Determining a corresponding second deviation value according to the expected temperature range of the associated component and the fluid temperature input and output data of the associated component;

[0039] Determining an allowable adjustment threshold value according to the component attribute data and the expected temperature range of the associated component;

[0040] If the second deviation value exceeds the allowable adjustment threshold, the flow control parameter of the associated component is determined according to the second deviation value.

[0041] By adopting the above technical solution, the flow control parameters of the target component can be accurately calculated based on the deviation between the fluid temperature input and output data in the target data and the expected interval. By calling the relevant data of the associated components, the flow and temperature of each component can be accurately adjusted to ensure the coordinated work of each component in the system and the high efficiency of heat exchange. In the case where the deviation value exceeds the allowable adjustment threshold, the flow control parameters of the relevant components can be automatically adjusted to maintain the stability of the system, prevent failures or energy losses caused by improper flow or excessively high / low temperature, and significantly improve the control accuracy and overall operating efficiency of the system.

[0042] In summary, the present application includes at least one of the following beneficial technical effects:

[0043] In order to solve the problems of high energy consumption and low efficiency in the decarbonization technology of traditional power plants, the present invention adopts liquid ammonia as a refrigerant for precooling and storing carbon dioxide, thereby improving energy utilization. Specifically, the heat exchange system for precooling carbon dioxide with liquid ammonia realizes efficient cooling and liquefaction of carbon dioxide through a two-stage heat exchange process. In this system, the parsed carbon dioxide first passes through the carbon dioxide precooling mechanism, and exchanges heat with the primary heat exchange liquid ammonia and the secondary heat exchange liquid ammonia in sequence to reduce the temperature of carbon dioxide and finally convert it into liquid carbon dioxide. During the heat exchange process, the primary heat exchange liquid ammonia and the secondary heat exchange liquid ammonia are respectively subjected to heat exchange to generate ammonia to be burned and liquid ammonia to be cooled. The liquid ammonia to be cooled is further heat exchanged with the cold-keeping liquid ammonia through the liquid ammonia heat exchange mechanism, converted into low-temperature cooling liquid ammonia, and then stored in the liquid ammonia storage mechanism; at the same time, the cold-keeping liquid ammonia is restored to the primary heat exchange liquid ammonia after heat exchange, and is re-supplied to the carbon dioxide precooling mechanism for heat exchange. The system effectively reduces energy consumption and improves energy utilization efficiency by rationally recycling the cold energy of liquid ammonia, and achieves efficient cooling and liquefaction of carbon dioxide through multi-stage heat exchange, providing a more efficient and energy-saving solution for the decarbonization process of power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a structural flow diagram of a heat exchange system for precooling carbon dioxide with liquid ammonia in one embodiment of the present application.

[0045] Figure 2 This is a schematic diagram of the specific structure of a heat exchange system for precooling carbon dioxide with liquid ammonia in one embodiment of the present application;

[0046] Figure 3 This is a flow chart of a control method for a heat exchange system for precooling carbon dioxide with liquid ammonia in one embodiment of the present application;

[0047] Figure 4 This is a flow chart for implementing step S50 in a heat exchange system for precooling carbon dioxide with liquid ammonia in one embodiment of the present application.

[0048] Description of reference numerals:

[0049] 1. Carbon dioxide precooling mechanism; 11. Primary precooler; 12. Secondary precooler; 13. Carbon dioxide economizer; 14. Carbon dioxide cryogenic refrigerator; 15. First expansion valve; 16. Second expansion valve; 2. Liquid ammonia heat exchange mechanism; 21. Water cooler; 22. Primary ammonia heat exchanger; 23. Secondary ammonia heat exchanger; 3. Liquid ammonia storage mechanism; 31. Subcooler; 32. Liquid ammonia storage tank; 33. First refrigeration pipeline; 34. Second refrigeration pipeline; 35. Liquid ammonia discharge pipeline liquid level regulating valve group; 36. Liquid ammonia delivery pump. DETAILED DESCRIPTION

[0050] The present application is further described in detail below in conjunction with the accompanying drawings.

[0051] In one embodiment, if Figure 1-Figure 2 As shown, the present application discloses a heat exchange system for precooling carbon dioxide with liquid ammonia, which specifically includes a carbon dioxide precooling mechanism 1, a liquid ammonia heat exchange mechanism 2 and a liquid ammonia storage mechanism 3;

[0052] The carbon dioxide input end of the carbon dioxide precooling mechanism 1 is used to receive the analyzed carbon dioxide, the first liquid ammonia input end of the carbon dioxide precooling mechanism 1 is connected to the first liquid ammonia output end of the liquid ammonia heat exchange mechanism 2 to receive the first-stage heat exchange liquid ammonia, the second liquid ammonia input end of the carbon dioxide precooling mechanism 1 is used to receive the second-stage heat exchange liquid ammonia, the liquid ammonia output end of the carbon dioxide precooling mechanism 1 is connected to the first liquid ammonia input end of the liquid ammonia heat exchange mechanism 2, the analyzed carbon dioxide is heat exchanged with the first-stage heat exchange liquid ammonia and the second-stage heat exchange liquid ammonia in turn, and the corresponding liquid carbon dioxide is generated and output, the first-stage heat exchange liquid ammonia generates the corresponding ammonia to be burned after the heat exchange, and the second-stage heat exchange liquid ammonia generates the corresponding liquid ammonia to be cooled after the heat exchange;

[0053] The first liquid ammonia input end of the liquid ammonia heat exchange mechanism 2 is connected to the liquid ammonia output end of the carbon dioxide precooling mechanism 1 for receiving the liquid ammonia to be cooled. The second liquid ammonia input end of the liquid ammonia heat exchange mechanism 2 is connected to the liquid ammonia output end of the liquid ammonia storage mechanism 3 for receiving the cold-keeping liquid ammonia. After the liquid ammonia to be cooled is heat-exchanged with the cold-keeping liquid ammonia, the liquid ammonia to be cooled is converted into cooled liquid ammonia and output to the liquid ammonia storage mechanism 3 through the second liquid ammonia output end of the liquid ammonia heat exchange mechanism 2. The cold-keeping liquid ammonia is converted into primary heat exchange liquid ammonia and output to the carbon dioxide precooling mechanism 1 through the first liquid ammonia output end of the liquid ammonia heat exchange mechanism 2.

[0054] In this embodiment, the heat exchange system of precooling carbon dioxide with liquid ammonia ensures that the system can operate efficiently and stably through precise connection and cooperation between various modules. First, the carbon dioxide input end of the carbon dioxide precooling mechanism 1 receives the parsed carbon dioxide fluid and starts heat exchange with liquid ammonia. Specifically, the first liquid ammonia input end of the carbon dioxide precooling mechanism 1 is connected to the first liquid ammonia output end of the liquid ammonia heat exchange mechanism 2. After the first-stage heat exchange liquid ammonia flows out of the liquid ammonia heat exchange mechanism 2, it is introduced into the carbon dioxide precooling mechanism 1, where liquid ammonia and carbon dioxide undergo preliminary heat exchange, and carbon dioxide is cooled and liquid carbon dioxide is produced. The second liquid ammonia input end of the carbon dioxide precooling mechanism 1 receives liquid ammonia from the second-stage heat exchange, and the liquid ammonia output end of the carbon dioxide precooling mechanism 1 is connected to the first liquid ammonia input end of the liquid ammonia heat exchange mechanism 2. After the transmission passes through the first-stage heat exchange and the second-stage heat exchange, ammonia to be burned and liquid ammonia to be cooled are generated respectively. The liquid ammonia heat exchange mechanism 2 receives liquid ammonia to be cooled and cold liquid ammonia through its first liquid ammonia input end and the second liquid ammonia input end, respectively, to ensure that the heat exchange process can be completed. During the heat exchange process between the liquid ammonia to be cooled and the cold-keeping liquid ammonia, the liquid ammonia to be cooled is further cooled in the liquid ammonia heat exchange mechanism 2, becomes cooled liquid ammonia and is output to the liquid ammonia storage mechanism 3 through the second liquid ammonia output end of the liquid ammonia heat exchange mechanism 2. At this time, the cooled liquid ammonia is transported to the liquid ammonia storage mechanism 3 to ensure that the system continues to obtain stable low-temperature liquid ammonia. At the same time, the cold-keeping liquid ammonia is also converted into primary heat exchange liquid ammonia through heat exchange in the liquid ammonia heat exchange mechanism 2, and is returned to the carbon dioxide precooling mechanism 1 through the first liquid ammonia output end of the liquid ammonia heat exchange mechanism 2 for secondary heat exchange. This control process ensures the effective recycling of liquid ammonia and maintains the temperature and liquid ammonia flow of each part within the expected range to achieve efficient operation of the system.

[0055] Furthermore, the fluid temperature at each liquid ammonia input and output end should be monitored by a real-time sensor and compared with the preset temperature expectation range so as to adjust the flow rate of liquid ammonia in time. Through the real-time acquisition of liquid ammonia temperature data, the system can dynamically adjust the flow control parameters between the modules to ensure that the liquid ammonia temperature in the carbon dioxide precooling mechanism 1 and the liquid ammonia heat exchange mechanism 2 is always maintained in the optimal heat exchange range, thereby improving the liquefaction efficiency of carbon dioxide and the cooling effect of liquid ammonia. In addition, the flow regulating device can accurately adjust the flow rate of liquid ammonia according to the size of the temperature deviation to avoid energy waste or insufficient heat exchange caused by excessive or too small liquid ammonia flow. At the same time, the liquid ammonia temperature and liquid level in the liquid ammonia storage mechanism 3 also need to be monitored in real time to ensure that the storage and supply of liquid ammonia can be sustained and stable, and respond quickly to system requirements when necessary, so as to avoid affecting the stability of the overall system due to insufficient or excessive liquid ammonia. Through such a dynamic adjustment and feedback mechanism, the system can maintain efficient operation under various load changes, ensure that the heat exchange process between liquid ammonia and carbon dioxide is always in the optimal state, and improve the overall efficiency and reliability of the system.

[0056] In summary, in order to solve the problems of high energy consumption and low efficiency in the decarbonization technology of traditional power plants, the present invention uses liquid ammonia as a refrigerant for precooling and storing carbon dioxide, thereby improving energy utilization. Specifically, the heat exchange system for precooling carbon dioxide with liquid ammonia realizes efficient cooling and liquefaction of carbon dioxide through a two-stage heat exchange process. In this system, the parsed carbon dioxide first passes through the carbon dioxide precooling mechanism 1, and is heat exchanged with the primary heat exchange liquid ammonia and the secondary heat exchange liquid ammonia in sequence to reduce the temperature of carbon dioxide and finally convert it into liquid carbon dioxide. During the heat exchange process, the primary heat exchange liquid ammonia and the secondary heat exchange liquid ammonia are heat exchanged respectively to generate ammonia to be burned and liquid ammonia to be cooled. The liquid ammonia to be cooled is further heat exchanged with the cold liquid ammonia through the liquid ammonia heat exchange mechanism 2, converted into low-temperature cooling liquid ammonia, and then stored in the liquid ammonia storage mechanism 3; at the same time, the cold liquid ammonia is restored to the primary heat exchange liquid ammonia after heat exchange, and is re-supplied to the carbon dioxide precooling mechanism 1 for heat exchange. The system effectively reduces energy consumption and improves energy utilization efficiency by rationally recycling the cold energy of liquid ammonia, and achieves efficient cooling and liquefaction of carbon dioxide through multi-stage heat exchange, providing a more efficient and energy-saving solution for the decarbonization process of power plants.

[0057] Further, such as Figure 1-Figure 2 As shown, the carbon dioxide precooling mechanism 1 includes a primary precooler 11, a secondary precooler 12 and a liquefaction unit;

[0058] The carbon dioxide input end of the primary precooler 11 is used to receive the analyzed carbon dioxide, the liquid ammonia input end of the primary precooler 11 is connected to the first liquid ammonia output end of the liquid ammonia heat exchange mechanism 2 to receive the primary heat exchange liquid ammonia, the carbon dioxide output end of the primary precooler 11 is connected to the carbon dioxide input end of the secondary precooler 12, so that the secondary precooler 12 receives the carbon dioxide after the primary heat exchange, and the ammonia output end of the primary precooler 11 is used to output ammonia to be burned;

[0059] The liquid ammonia input end of the liquefaction unit is used to receive the secondary heat exchange liquid ammonia, the liquid ammonia input end of the secondary precooler 12 is connected to the liquid ammonia output end of the liquefaction unit, so that the secondary precooler 12 receives the secondary heat exchange liquid ammonia, and the carbon dioxide output end of the secondary precooler 12 is connected to the carbon dioxide input end of the liquefaction unit, so that the liquefaction unit liquefies the carbon dioxide after the secondary heat exchange.

[0060] In this embodiment, the carbon dioxide precooling mechanism 1 is composed of a primary precooler 11, a secondary precooler 12 and a liquefaction unit, and the connection relationship between the modules is closely coordinated to ensure the efficient operation of the system. The carbon dioxide input end of the primary precooler 11 is used to receive the analyzed carbon dioxide. After the heat exchange of the primary precooler 11, the liquid ammonia input end of the primary precooler 11 receives the primary heat exchange liquid ammonia from the first liquid ammonia output end of the liquid ammonia heat exchange mechanism 2. In the primary precooler 11, carbon dioxide and liquid ammonia are heat exchanged, resulting in a decrease in the temperature of carbon dioxide. At the same time, the liquid ammonia is heated to generate ammonia to be burned, which is discharged through the ammonia output end of the primary precooler 11. The carbon dioxide output end of the primary precooler 11 is connected to the carbon dioxide input end of the secondary precooler 12, and the carbon dioxide that has been precooled at the primary stage is transported to the secondary precooler 12. In the secondary precooler 12, carbon dioxide continues to exchange heat with liquid ammonia to further reduce its temperature. The liquid ammonia input end of the secondary precooler 12 receives the secondary heat exchange liquid ammonia from the liquid ammonia output end of the liquefaction unit, and the carbon dioxide output end of the secondary precooler 12 is connected to the carbon dioxide input end of the liquefaction unit, and the carbon dioxide that has undergone secondary precooling is sent to the liquefaction unit. The liquefaction unit completes the liquefaction process of carbon dioxide by further cooling and compressing the carbon dioxide. In this process, the heat exchange and fluid control of liquid ammonia and carbon dioxide complement each other to ensure that the temperature of carbon dioxide is gradually reduced to the liquefaction condition, and the circulation flow of liquid ammonia in the system is also precisely controlled to maintain appropriate heat exchange efficiency and system stability. Through such a layout, the fluid temperature, flow rate and heat exchange process between each module are closely coordinated to achieve efficient precooling and liquefaction of carbon dioxide, while ensuring the optimal flow state of liquid ammonia to avoid energy waste and system failure.

[0061] Specifically, the heat exchange effect of the first-stage precooler 11 and the second-stage precooler 12 needs to be accurately calculated during the design to ensure that the cooling temperature and flow rate of carbon dioxide at each stage meet the predetermined liquefaction requirements. The contact efficiency of liquid ammonia and carbon dioxide in the heat exchanger directly affects the performance of the entire system. Therefore, when optimizing the design of the heat exchanger, it is possible to consider increasing the heat exchange area, increasing the liquid ammonia flow rate, or using high-efficiency heat exchange materials to improve the cooling efficiency and heat exchange rate. In addition, the synergy between the carbon dioxide economizer 13 and the carbon dioxide cryogenic refrigerator 14 in the liquefaction unit is particularly important because they not only undertake the task of further cooling and liquefying carbon dioxide, but also determine the quality and energy efficiency of the final liquefied carbon dioxide. In order to improve the stability of the liquefaction process, a fine temperature control and pressure control system can be designed to ensure that the temperature and pressure of carbon dioxide are always kept within the ideal liquefaction range. Furthermore, in view of the energy-saving needs of the system, a heat recovery device can be used in the carbon dioxide precooling process to recover the heat emitted during the cooling process of the precooler and use it for preheating liquid ammonia, reducing the consumption of external energy. Finally, with the continuous development of technology, the system can introduce intelligent monitoring and optimization functions, use sensors to detect temperature, pressure and other data in real time, and combine machine learning algorithms to optimize control strategies, achieve adaptive adjustment and fault warning, and further improve the safety and operation efficiency of the system.

[0062] In summary, the configuration of the primary precooler 11, the secondary precooler 12 and the liquefaction unit in the carbon dioxide precooling mechanism 1 can effectively cool the carbon dioxide step by step at different heat exchange stages, and further liquefy the carbon dioxide through the liquefaction unit. This design not only improves the liquefaction efficiency of carbon dioxide, but also can accurately control the temperature and pressure at each stage, ensuring that the carbon dioxide is always in the best state during the liquefaction process, and reducing the energy consumption and operation difficulty of carbon dioxide liquefaction.

[0063] Further, such as Figure 1-Figure 2 As shown, the liquefaction unit includes a carbon dioxide economizer 13 and a carbon dioxide cryogenic refrigerator 14. The liquid ammonia input end of the carbon dioxide economizer 13 and the liquid ammonia input end of the carbon dioxide cryogenic refrigerator 14 are both used to receive secondary heat exchange liquid ammonia. The liquid ammonia output end of the carbon dioxide economizer 13 and the liquid ammonia output end of the carbon dioxide cryogenic refrigerator 14 are both connected to the liquid ammonia input end of the secondary precooler 12. The carbon dioxide input end of the carbon dioxide economizer 13 is connected to the carbon dioxide output end of the secondary precooler 12. The carbon dioxide output end of the carbon dioxide economizer 13 is connected to the carbon dioxide input end of the carbon dioxide cryogenic refrigerator 14. After successively passing through the cooling effect of the secondary heat exchange liquid ammonia in the carbon dioxide economizer 13 and the carbon dioxide cryogenic refrigerator 14, the carbon dioxide after the secondary heat exchange is converted into liquid carbon dioxide. The carbon dioxide output end of the carbon dioxide cryogenic refrigerator 14 is used to output liquid carbon dioxide.

[0064] In this embodiment, the liquefaction unit is composed of a carbon dioxide economizer 13 and a carbon dioxide cryocooler 14, which together complete the liquefaction process of the carbon dioxide that has undergone secondary precooling. The liquid ammonia input end of the carbon dioxide economizer 13 receives the secondary heat exchange liquid ammonia from the liquid ammonia input end of the carbon dioxide cryocooler 14, and these liquid ammonia are used to absorb heat from carbon dioxide, reduce the temperature of carbon dioxide, and make it closer to the liquefaction condition. At the same time, the liquid ammonia input end of the carbon dioxide cryocooler 14 also receives the secondary heat exchange liquid ammonia so as to exchange heat with carbon dioxide inside it. After the liquid ammonia passes through the cooling effect of the carbon dioxide economizer 13 and the carbon dioxide cryocooler 14, the temperature of carbon dioxide is further reduced, and finally the carbon dioxide is converted into liquid carbon dioxide after passing through these two devices. The carbon dioxide input end of the carbon dioxide economizer 13 is connected to the carbon dioxide output end of the secondary precooler 12, and the carbon dioxide after the secondary precooling is transported to the carbon dioxide economizer 13, where the carbon dioxide continues to exchange heat with the liquid ammonia and is further cooled. The carbon dioxide output end of the carbon dioxide economizer 13 is connected to the carbon dioxide input end of the carbon dioxide cryocooler 14, and the cooled carbon dioxide is transported to the carbon dioxide cryocooler 14, where the carbon dioxide is further cooled until it is completely liquefied. Finally, the carbon dioxide output end of the carbon dioxide cryocooler 14 outputs the liquid carbon dioxide to complete the liquefaction process. In this process, the circulation of liquid ammonia between the carbon dioxide economizer 13 and the carbon dioxide cryocooler 14 not only plays a cooling role, but also ensures that the temperature of the carbon dioxide gradually drops to the liquefaction condition, while controlling the energy flow and cooling effect of the system;

[0065] Specifically, the carbon dioxide economizer 13 and the carbon dioxide cryogenic refrigerator 14 work closely together to achieve efficient heat exchange through the circulation of liquid ammonia. Liquid ammonia flows repeatedly in these two devices, playing a core role in cooling carbon dioxide, and the temperature of carbon dioxide gradually decreases, prompting it to eventually convert into liquid form. In order to ensure the efficiency of heat exchange, the liquid ammonia flow and temperature between the carbon dioxide economizer 13 and the carbon dioxide cryogenic refrigerator 14 need to be precisely controlled to cope with changes under different load conditions. The temperature and flow parameters of each module in the system should not only be monitored in real time, but also adjusted according to the expected temperature range to ensure that the liquid ammonia temperature is always in the best heat exchange state, avoiding insufficient heat exchange or energy waste due to too low or too high temperature. At the same time, the temperature data of carbon dioxide and liquid ammonia in the liquefaction process should also be synchronously fed back to the central control system so as to adjust the input and output flow of liquid ammonia according to real-time data, thereby optimizing the heat exchange efficiency. In order to avoid energy loss, the system should be designed with an appropriate heat recovery mechanism to return part of the energy that is not completely cooled in the carbon dioxide cryogenic refrigerator 14 to the liquid ammonia heat exchange system, further improving the energy utilization of the overall system. In addition, the system's heat exchange process should also have fault detection and emergency response functions to cope with the decline in cooling efficiency that may be caused by liquid ammonia flow, temperature fluctuations or equipment failures, thereby ensuring the safe and stable operation of the liquefaction process.

[0066] In summary, the energy efficiency of liquid carbon dioxide can be effectively improved. The series configuration of the carbon dioxide economizer 13 and the cryocooler reduces the use of cooling medium and optimizes the heat exchange process through staged cooling and energy recovery, thereby reducing liquid ammonia consumption and energy loss and improving the overall energy efficiency of the system.

[0067] Further, such as Figure 1-Figure 2 As shown, the liquid ammonia input end of the carbon dioxide economizer 13 is connected to the first expansion valve 15, and the liquid ammonia input end of the carbon dioxide cryogenic refrigerator 14 is connected to the second expansion valve 16. The first expansion valve 15 and the second expansion valve 16 both reduce the temperature of the secondary heat exchange liquid ammonia through expansion throttling, thereby reducing the temperature of the secondary heat exchange liquid ammonia to cool the carbon dioxide after the secondary heat exchange.

[0068] In summary, the secondary heat exchange liquid ammonia can be cooled by expansion throttling before entering the carbon dioxide economizer 13 and the cryogenic refrigerator, thereby effectively reducing the temperature of the liquid ammonia, so that it can better provide cold energy for the liquefaction process of carbon dioxide. This throttling and cooling method improves the cooling efficiency of carbon dioxide and ensures that the entire process is carried out on the basis of energy saving.

[0069] Further, such as Figure 1-Figure 2 As shown, the liquid ammonia heat exchange mechanism 2 includes a water cooler 21, a primary ammonia heat exchanger 22 and a secondary ammonia heat exchanger 23;

[0070] The liquid ammonia input end of the water cooler 21 is connected to the liquid ammonia output end of the carbon dioxide precooling mechanism 1, the liquid ammonia output end of the water cooler 21 is connected to the first liquid ammonia input end of the primary ammonia heat exchanger 22, the first liquid ammonia output end of the primary ammonia heat exchanger 22 is connected to the first liquid ammonia input end of the secondary ammonia heat exchanger 23, and the first liquid ammonia output end of the secondary ammonia heat exchanger 23 is connected to the liquid ammonia input end of the liquid ammonia storage mechanism 3;

[0071] The liquid ammonia output end of the liquid ammonia storage mechanism 3 is connected to the second liquid ammonia input end of the secondary ammonia heat exchanger 23, the second liquid ammonia output end of the secondary ammonia heat exchanger 23 is connected to the second liquid ammonia input end of the primary ammonia heat exchanger 22, and the second liquid ammonia output end of the primary ammonia heat exchanger 22 is connected to the first liquid ammonia input end of the carbon dioxide precooling mechanism 1;

[0072] Among them, the water cooler 21 is connected to a water cooling pipe, in which cooling water flows, and the first-level ammonia heat exchanger 22 and the second-level ammonia heat exchanger 23 are circulated with cold liquid ammonia output from the liquid ammonia storage mechanism 3. Under the cooling effect of the cooling water and the cold liquid ammonia in turn, the cooled liquid ammonia is converted into cooled liquid ammonia, and is transported to the liquid ammonia storage mechanism 3 through the first liquid ammonia output end of the second-level ammonia heat exchanger 23 for storage and cold preservation.

[0073] In this embodiment, the liquid ammonia heat exchange mechanism 2 ensures timely cooling and transportation of liquid ammonia in the system through the synergistic effect of multiple components, and optimizes the heat exchange process. The liquid ammonia input end of the water cooler 21 is connected to the liquid ammonia output end of the carbon dioxide precooling mechanism 1. In the initial stage, the liquid ammonia is preliminarily cooled by the water cooler 21, and the cooled liquid ammonia is transported to the first liquid ammonia input end of the primary ammonia heat exchanger 22 through the liquid ammonia output end of the water cooler 21. The function of the primary ammonia heat exchanger 22 is to further adjust the temperature of the liquid ammonia to reach the required cooling level. Its first liquid ammonia output end transports the cooled liquid ammonia to the first liquid ammonia input end of the secondary ammonia heat exchanger 23, and continues to perform temperature control on the liquid ammonia. The first liquid ammonia output end of the secondary ammonia heat exchanger 23 is connected to the liquid ammonia input end of the liquid ammonia storage mechanism 3 to achieve storage and cold preservation of liquid ammonia. When the liquid ammonia is gradually cooled to the set temperature through the above process, the liquid ammonia output end of the liquid ammonia storage mechanism 3 is connected to the second liquid ammonia input end of the secondary ammonia heat exchanger 23, providing cold liquid ammonia as a cooling source. The cold liquid ammonia exchanges heat with the liquid ammonia to be cooled in the secondary ammonia heat exchanger 23, and the second liquid ammonia output end of the secondary ammonia heat exchanger 23 transports the cooled liquid ammonia to the second liquid ammonia input end of the primary ammonia heat exchanger 22, and further heat exchange is carried out through the liquid ammonia heat exchanger system. Finally, the second liquid ammonia output end of the primary ammonia heat exchanger 22 is connected to the first liquid ammonia input end of the carbon dioxide precooling mechanism 1, and the liquid ammonia after two-stage heat exchange is returned to the carbon dioxide precooling mechanism 1 to continue to participate in the precooling process of carbon dioxide. During the whole process, the water cooler 21 ensures that the liquid ammonia in the system can effectively exchange heat in each heat exchanger through the water cooling pipe and the flowing cooling water, maintains the stable cooling effect of the liquid ammonia, keeps it in a low temperature and cold state in the liquid ammonia storage mechanism 3, and provides continuous cooling support for the liquefaction process of carbon dioxide.

[0074] Specifically, in the working process of this liquid ammonia heat exchange mechanism 2, in addition to the basic temperature regulation function, the efficiency and stability of the entire heat exchange process are also closely related to the regulation and control mechanism of the system. Liquid ammonia can be cooled in stages in different temperature ranges through the circulation of multiple heat exchangers to ensure that the cooling effect of liquid ammonia is optimized in each heat exchange stage. In order to further improve the heat exchange efficiency of the system, an intelligent regulation and control strategy can be introduced to monitor the key parameters such as the flow rate, temperature and pressure of liquid ammonia and cooling water in real time, and dynamically adjust the flow rate of each heat exchanger and the flow rate of the heat exchange medium according to different working conditions. For example, when the temperature of liquid ammonia approaches the set threshold, the control system can automatically adjust the flow distribution of the primary ammonia heat exchanger 22 and the secondary ammonia heat exchanger 23 to prevent overcooling or overheating, thereby ensuring the heat exchange efficiency and stability. In addition, the heat transfer effect between the water cooler 21 and the liquid ammonia heat exchanger may be affected by the temperature and flow rate of the cooling water, so it is necessary to compensate for the influence of water temperature fluctuations on the cooling effect through dynamic regulation of the water flow. The flow rate of cold liquid ammonia in the liquid ammonia storage mechanism 3 can also be adjusted in real time through the monitoring system to ensure that the amount of cooling liquid ammonia entering the secondary ammonia heat exchanger 23 matches the amount of liquid ammonia that needs to be cooled, avoiding unnecessary energy waste. At the same time, by recycling the cold energy of low-temperature liquid ammonia and providing cooling support for other process links, the energy utilization efficiency of the overall system can be improved and the goal of energy conservation and emission reduction can be achieved. These enhanced control and regulation functions will further optimize the flow path and heat exchange process of liquid ammonia and improve the working efficiency and reliability of the overall system.

[0075] In summary, the cooling effect of liquid ammonia can be effectively improved. The water cooler 21, by combining with the water cooling pipe, uses the efficient heat exchange capacity of cooling water to reduce the temperature of liquid ammonia; the primary and secondary ammonia heat exchangers 23 further cool down through multi-stage heat exchange to ensure that the liquid ammonia to be cooled can be fully cooled and finally stored as cold liquid ammonia. This multi-stage cooling method reduces the dependence on external cooling media, while improving the cooling efficiency and storage safety of liquid ammonia.

[0076] Further, such as Figure 1-Figure 2 As shown, the liquid ammonia storage mechanism 3 includes a subcooler 31 and a liquid ammonia storage tank 32, the liquid ammonia input end of the subcooler 31 is connected to the second liquid ammonia output end of the liquid ammonia heat exchange mechanism 2, the liquid ammonia output end of the subcooler 31 is connected to the liquid ammonia input end of the liquid ammonia storage tank 32, and the liquid ammonia output end of the liquid ammonia storage tank 32 is connected to the second liquid ammonia input end of the liquid ammonia heat exchange mechanism 2;

[0077] The subcooler 31 is connected to a first refrigeration pipe 33, and the refrigerant flowing in the first refrigeration pipe 33 is used to perform primary refrigeration insulation on the cooled liquid ammonia. The liquid ammonia storage tank 32 is connected to a second refrigeration pipe 34, and the second refrigeration pipe 34 is provided with a flowing refrigerant to perform secondary refrigeration insulation on the cooled liquid ammonia after primary refrigeration insulation, and then convert it into refrigerated liquid ammonia, and output the refrigerated liquid ammonia through the liquid ammonia output end of the liquid ammonia storage tank 32.

[0078] In this embodiment, in the liquid ammonia storage mechanism 3, the storage and cooling process of liquid ammonia is carried out through the cooperation of the subcooler 31 and the liquid ammonia storage tank 32, ensuring that the liquid ammonia remains at a low temperature during storage and preventing its temperature from rising. First, the liquid ammonia input end of the subcooler 31 is connected to the second liquid ammonia output end of the liquid ammonia heat exchange mechanism 2, and the liquid ammonia enters the subcooler 31 through this path for primary cooling. The refrigerant flowing in the subcooler 31 cools the liquid ammonia through the first refrigeration pipe 33, further reducing the temperature of the liquid ammonia to the required level. After the first level of cold preservation, the liquid ammonia flows to the liquid ammonia input end of the liquid ammonia storage tank 32 through the liquid ammonia output end of the subcooler 31, and is further stored in the liquid ammonia storage tank 32. The liquid ammonia storage tank 32 is connected to another refrigerant circulation pipe through the second refrigeration pipe 34, and the refrigerant flowing in the liquid ammonia storage tank 32 performs secondary cooling on the liquid ammonia. After the first-level cold-insulated liquid ammonia enters the liquid ammonia storage tank 32, it is cooled again by the refrigerant flowing in the second refrigeration pipe 34 to ensure that the temperature of the liquid ammonia remains in a suitable storage range and is converted into cold-insulated liquid ammonia. The liquid ammonia output end of the liquid ammonia storage tank 32 is responsible for outputting cold-insulated liquid ammonia, which is supplied to the second liquid ammonia input end of the liquid ammonia heat exchange mechanism 2 or other required system parts. In this process, the cooling effect of each link is independent of each other and carried out in an orderly manner, ensuring that the temperature control of the liquid ammonia meets the precise requirements during the entire storage and cooling process, thereby ensuring the stable operation of the system and the efficient use of liquid ammonia. In this process, real-time monitoring of flow and temperature is the key, which can help adjust the cooling efficiency of each link, avoid temperature fluctuations of liquid ammonia at various stages, and improve the operating efficiency of the overall system.

[0079] Specifically, the liquid ammonia in the liquid ammonia storage tank 32 not only needs to be effectively kept cold by the supercooler 31 and the secondary refrigeration pipeline, but also the impact of real-time changes in temperature and pressure on the storage of liquid ammonia and its subsequent use should be considered. For example, a temperature sensor and a pressure sensor are configured in the liquid ammonia storage tank 32 to monitor the temperature and pressure changes of the liquid ammonia in real time. When the temperature of the liquid ammonia is too high or the pressure fluctuation exceeds the set threshold, the system can automatically adjust the refrigerant flow rate or adjust the working state of the cooling system to ensure that the liquid ammonia always remains in an ideal liquid state during the entire storage process. In order to further optimize the storage and transportation efficiency of liquid ammonia, the liquid ammonia storage tank 32 can also be configured with an automated control system to automatically calculate and adjust the cooling parameters based on real-time data to make the liquid ammonia cooling process more accurate and efficient. In addition, the design of the liquid ammonia storage mechanism 3 can also be integrated into an energy efficiency optimization scheme, such as by optimizing the flow path of the refrigerant in the first refrigeration pipeline 33 and the second refrigeration pipeline 34, reducing energy losses, improving the overall efficiency of the refrigeration system, and reducing energy consumption. At the same time, the design of the liquid ammonia storage tank 32 can consider adding a recovery mechanism to recycle the low-temperature waste heat generated during the cooling process, further improve the energy efficiency and environmental friendliness of the system, and thus achieve sustainable development of the liquid ammonia storage and use process.

[0080] In summary, it is possible to ensure that the liquid ammonia is kept at a low temperature and avoid temperature fluctuations during storage. The supercooler 31 ensures that the cooled liquid ammonia can maintain the required temperature range through the primary cold preservation and the liquid ammonia storage tank 32 through the secondary cold preservation, and minimizes heat exchange during storage, ensuring that the liquid ammonia is always at a suitable temperature during storage, thereby improving storage stability and safety.

[0081] Further, such as Figure 1-Figure 2 As shown, a liquid ammonia discharge pipeline liquid level regulating valve group 35 is provided between the liquid ammonia output end of the liquid ammonia storage tank 32 and the second liquid ammonia input end of the liquid ammonia heat exchange mechanism 2 .

[0082] In this embodiment, a liquid ammonia discharge pipeline liquid level regulating valve group 35 is set between the liquid ammonia output end of the liquid ammonia storage tank 32 and the second liquid ammonia input end of the liquid ammonia heat exchange mechanism 2. The main purpose is to accurately control the liquid level of liquid ammonia in the storage tank, so as to ensure the stability and safety of liquid ammonia output. Specifically, the liquid ammonia in the liquid ammonia storage tank 32 may cause liquid level fluctuations due to factors such as temperature and pressure when being stored and adjusted. In order to prevent excessive or insufficient liquid ammonia from flowing to the liquid ammonia heat exchange mechanism 2, the liquid level regulating valve group automatically adjusts the output of liquid ammonia by monitoring the liquid ammonia level changes in real time. When the liquid level in the liquid ammonia storage tank 32 is too high, the regulating valve group can be opened in time to discharge or distribute the excess liquid ammonia to other system parts to ensure that the amount and flow rate of liquid ammonia flowing to the liquid ammonia heat exchange mechanism 2 are maintained within a predetermined range to avoid overloading the liquid ammonia system; on the contrary, when the liquid level is too low, the valve group will reduce the amount of liquid ammonia discharge or close the corresponding pipeline to prevent insufficient liquid ammonia output. The automatic control function of the regulating valve group can achieve intelligent regulation through the cooperation of liquid level sensors, temperature sensors and pressure sensors to ensure the stability of the entire liquid ammonia flow process. At the same time, the setting of the liquid level regulating valve group can also improve the accuracy of liquid ammonia delivery, reduce errors and potential risks caused by human operation, and enhance the reliability and safety of system operation. The core role of the regulating valve group in this process is to serve as a flow regulating device for liquid ammonia output, and together with other parts, maintain the stability, reliability and safety of liquid ammonia supply.

[0083] In summary, precise liquid level control can be achieved during the storage of liquid ammonia. By adjusting the liquid level, a stable supply of liquid ammonia and an appropriate coolant flow rate can be ensured, and uneven cooling or energy waste caused by too low or too high a liquid level can be avoided, thereby improving the safety and reliability of the system.

[0084] Further, such as Figure 1-Figure 2 As shown, a liquid ammonia delivery pump 36 is provided between the liquid ammonia discharge pipeline liquid level regulating valve group 35 and the second liquid ammonia input end of the liquid ammonia heat exchange mechanism 2 .

[0085] In this embodiment, a liquid ammonia delivery pump 36 is provided between the liquid ammonia discharge pipeline liquid level regulating valve group 35 and the second liquid ammonia input end of the liquid ammonia heat exchange mechanism 2, which is mainly used to ensure the stable delivery and flow control of liquid ammonia in the system. The liquid ammonia delivery pump 36 can accurately adjust the liquid ammonia from the liquid ammonia storage tank 32 to the second liquid ammonia input end of the liquid ammonia heat exchange mechanism 2 through the liquid ammonia discharge pipeline according to the adjustment signal of the liquid level regulating valve group by controlling the flow velocity and flow of liquid ammonia. The role of the liquid ammonia delivery pump 36 in this process is crucial, especially when the liquid level regulating valve group adjusts the output of liquid ammonia, the delivery pump ensures that the flow of liquid ammonia is not hindered and the flow rate remains stable, avoiding the shortage or excess of liquid ammonia. The liquid level regulating valve group automatically adjusts the opening and closing of the valve according to the liquid level data in the liquid ammonia storage tank 32, thereby adjusting the output of liquid ammonia, and the liquid ammonia delivery pump 36 adjusts the flow rate of liquid ammonia in real time according to this change, ensuring that liquid ammonia can be input to the second liquid ammonia input end of the liquid ammonia heat exchange mechanism 2 at a constant flow rate, and maintaining the normal operation of the heat exchange system. At the same time, the control logic of the liquid ammonia delivery pump 36 cooperates with the liquid level sensor, temperature sensor, pressure sensor and other equipment to ensure the accurate execution of the pump start and stop, flow control and pressure regulation operations, and avoid system abnormalities caused by poor or excessive liquid ammonia flow. The liquid ammonia delivery pump 36 not only ensures the effective transmission of liquid ammonia, but also provides reliable support for the dynamic regulation of the entire liquid ammonia system.

[0086] In summary, the stable delivery of liquid ammonia can be ensured and the accuracy of flow regulation can be improved. The liquid ammonia delivery pump 36 can adjust the flow rate of liquid ammonia during storage and heat exchange, ensuring smooth flow of liquid ammonia in each link, further improving heat exchange efficiency and reducing energy consumption.

[0087] Specifically, the process flow of carbon dioxide cooling and high-pressure 1.2MPa room-temperature liquid ammonia refrigeration is as follows: the analyzed carbon dioxide generally has a temperature of about 80°C, and needs to be cooled by a water cooler (not shown), dehydrated by a gas-liquid separator, and pressurized to 1.9MPa by a compressor. After dehydration by a molecular sieve, it enters a primary precooler 11 (the cooling water required for this process is supplied from a water cooler 21). The primary precooler 11 will cool the carbon dioxide from 40°C to 30°C, and the primary heat exchange liquid ammonia in the shell side will be raised from 5°C to 25°C to generate ammonia to be burned; then The carbon dioxide enters the secondary precooler 12, and the secondary heat exchange liquid ammonia with a temperature of -25 to -20°C after passing through the carbon dioxide economizer 13 and the carbon dioxide cryogenic refrigerator 14 will cool the 30°C carbon dioxide to 0°C; then the 0°C carbon dioxide enters the carbon dioxide economizer 13, and the liquid ammonia passing through the first expansion valve 15 and the second expansion valve 16 will reach -40°C. The 0°C carbon dioxide will first be cooled to -15°C, and then enter the carbon dioxide cryogenic refrigerator 14, and the -15°C carbon dioxide will be cooled to -28°C to form liquid carbon dioxide. Then, the low-temperature liquid ammonia passing through the first expansion valve 15 and the second expansion valve 16 in the carbon dioxide economizer 13 and the carbon dioxide cryogenic refrigerator 14 will be mixed and flow through the pipe process of the carbon dioxide secondary precooler 12 after heat exchange with carbon dioxide, so as to form the above-mentioned secondary heat exchange liquid ammonia with a temperature of -25 to -20°C after passing through the carbon dioxide economizer 13 and the carbon dioxide cryogenic refrigerator 14, and then enter the water cooler 21. The water cooler 21 mainly provides low-temperature 5°C cooling water for carbon dioxide, and converts 80°C The carbon dioxide is cooled to 40°C (i.e. the carbon dioxide decomposed as mentioned at the beginning is generally at a temperature of about 80°C and needs to be cooled by a water cooler first); the temperature of the liquid ammonia to be cooled flowing out of the water cooler 21 is -15°C, and the primary ammonia heat exchanger 22 and the secondary ammonia heat exchanger 23 use the supercooled -35°C cold liquid ammonia stored in the liquid ammonia storage tank 32 for precooling, cooling the liquid ammonia to be cooled from -15°C to -25°C cooled liquid ammonia, and then supercooling the liquid ammonia through the supercooler 31 to form -35°C cold liquid ammonia. The liquid ammonia storage tank 32 is provided with a liquid ammonia discharge pipeline liquid level regulating valve group 35; the liquid ammonia delivery pump 36 transports the -35°C cold liquid ammonia to the outside first through the primary ammonia heat exchanger 22 and the secondary ammonia heat exchanger 23, and then heats the liquid ammonia with the high-temperature carbon dioxide after flowing through the carbon dioxide primary cooler, and finally sends it to the ammonia burner of the power plant boiler for combustion.

[0088] like Figure 3 As shown, a control method for a heat exchange system for precooling carbon dioxide with liquid ammonia is applied to a heat exchange system for precooling carbon dioxide with liquid ammonia. The control method includes:

[0089] S10, obtaining a concerned heat exchange path, and determining concerned components and association relationships between concerned components according to the concerned heat exchange path;

[0090] In this embodiment, the heat exchange path of interest refers to the flow route of carbon dioxide in the heat exchange system, from the analyzer through various cooling devices, such as the primary precooler 11, the secondary precooler 12, the carbon dioxide economizer 13, and the carbon dioxide cryogenic refrigerator 14, and finally enters the liquefaction unit for liquefaction. Each module exchanges heat through fluids (such as liquid ammonia and carbon dioxide), and each module in the path assumes different cooling or heating functions. The components of interest refer to components that are directly related to these heat exchange processes and require precise control, such as the primary precooler 11, the secondary precooler 12, the carbon dioxide economizer 13, the carbon dioxide cryogenic refrigerator 14, and the liquid ammonia storage tank 32, etc. The operating status of these components will directly affect the heat exchange effect of the entire system. By establishing an association relationship between the components of interest, the control system can understand how the components interact with each other and make dynamic adjustments in real-time operations. The establishment of an association relationship helps to identify which other components may also be affected when a problem occurs in a certain component and need to be adjusted synchronously.

[0091] S20, determining an expected temperature range of the component of interest, where the expected temperature range includes an expected fluid input temperature range and an expected fluid output temperature range;

[0092] In this embodiment, the expected temperature range refers to the ideal temperature range for the fluid in each component of interest. For example, in the primary precooler 11, the inflowing carbon dioxide gas should be around 30°C, and the temperature when flowing out should be reduced to 0°C; and in the liquid ammonia storage tank 32, the expected temperature value of the liquid ammonia should be -35°C to better achieve heat exchange. The expected temperature range of each component is set according to its function and fluid state requirements. For example, the cooling effect of liquid ammonia in the carbon dioxide economizer 13 and the carbon dioxide cryogenic refrigerator 14 requires that the liquid ammonia temperature be maintained between -20°C and -15°C to ensure that the carbon dioxide can be sufficiently cooled. Setting a reasonable expected temperature range is the basis for ensuring the efficient operation of the heat exchange system. It not only ensures the stability of the system, but also helps the control system to respond promptly when deviations occur.

[0093] S30, obtaining fluid temperature input and output data of the component of interest;

[0094] In this embodiment, obtaining fluid temperature input and output data refers to real-time monitoring of the temperature of carbon dioxide and liquid ammonia through temperature sensors installed in various components of interest. These sensors will collect real-time temperature data and transmit it to the control system. For example, before carbon dioxide enters the primary precooler 11, its input temperature may be around 80°C, and the output temperature after passing through the primary precooler 11 should be 30°C. Accurate temperature data collection is required in each component of interest, especially during the heat exchange process. Through these real-time data, the system can determine whether the current heat exchange is in the desired state and provide data support for subsequent adjustments.

[0095] S40, determining whether the temperature input and output data fall within the corresponding expected temperature range, and if so, adding or maintaining the corresponding visualization feature in the constructed visualization platform;

[0096] In this embodiment, the control system will determine in real time whether the input and output temperatures of the fluid are within the expected range. If the temperature data is within the preset range, the system will mark the status of the component as normal, and display green or other symbols through the visualization platform, indicating that the current system status is normal and there is no abnormality in the heat exchange process. If the temperature data of the fluid falls outside the normal range, the system will immediately display red or other warning symbols, indicating that there may be a problem, prompting the operator to conduct further inspection. Through the visualization platform, the operator can clearly see the temperature conditions of each component, helping to promptly discover and solve potential problems and ensure the long-term stable operation of the system.

[0097] S50. If not, determine that the component of interest is the target component, determine the fluid temperature input and output data and the expected temperature range as target data, and determine the associated component corresponding to the target component based on the association relationship, call the associated data of the associated component, determine whether the associated component is the same as the target component based on the associated data, determine the corresponding flow control parameters based on the target data, and the flow control parameters are used to adjust the fluid speed in the component of interest and the target component.

[0098] In this embodiment, when the temperature input and output data of a component of interest fails to meet the expected interval, the component is regarded as a target component. At this time, the control system will determine the target data based on the difference between the fluid temperature of the target component and the expected interval, and search for other components that are associated with the target component. For example, if the output temperature of the first-stage precooler 11 is too high, it may be necessary to adjust the flow rate of liquid ammonia flowing through the carbon dioxide economizer 13 or the carbon dioxide cryogenic refrigerator 14 to ensure that the carbon dioxide is properly cooled in these components. Through the operating data of the associated components, the system can dynamically adjust the flow control parameters and automatically adjust the fluid flow rate to correct the temperature deviation. The adjustment of the flow control parameters will directly affect the heat exchange efficiency and cooling effect of the fluid, thereby helping to restore the normal operation of the entire system.

[0099] Specifically, for example, in a heat exchange system in which liquid ammonia precools carbon dioxide, it is assumed that the temperature of carbon dioxide received at the input end of the primary precooler 11 is 80°C, and after passing through the primary precooler 11, the temperature of carbon dioxide should drop to 30°C. At this time, the control system will monitor the input temperature and output temperature data of the primary precooler 11 in real time. If the system detects that the output temperature fails to reach the expected 30°C, for example, the output temperature is 35°C, the system will determine that the temperature data of the component does not meet the expected range, and the primary precooler 11 becomes the target component. Subsequently, the control system will check other components associated with the primary precooler 11 based on the association relationship, such as the carbon dioxide economizer 13 and the liquid ammonia flow control system, to see whether the working status of these components may affect the temperature control of the primary precooler 11. The system may adjust the liquid ammonia flow rate flowing through the carbon dioxide economizer 13 to increase the cooling effect of the liquid ammonia, thereby reducing the output temperature of the primary precooler 11 to 30°C. This method of automatically adjusting the fluid flow can ensure the temperature stability of the heat exchange system and avoid excessive temperature deviation of any component, thereby ensuring the optimization of the carbon dioxide precooling effect.

[0100] In summary, by accurately acquiring the temperature input and output data of the components of interest and the expected temperature range of the fluid, the system operation status can be monitored in real time to ensure that the temperature is controlled within a reasonable range. When the temperature deviates from the expected value, the relevant components can be discovered and adjusted in time to avoid system performance degradation or energy waste due to abnormal temperature, thereby improving the stability and operation efficiency of the system. At the same time, the matching of the expected temperature range of the associated components and the fluid temperature data can ensure that the temperature remains balanced during the collaborative heat exchange process of multiple components, further improving the response speed and reliability of the overall heat exchange system.

[0101] In one embodiment, if Figure 4 As shown, in step S50, the associated data of the associated component is called, and the steps of determining whether the associated component is the same as the target component according to the associated data and determining the corresponding flow control parameter according to the target data include:

[0102] S501, determining a corresponding first deviation value according to fluid temperature input and output data and a temperature expected range in the target data, and determining a flow control parameter of a target component according to the first deviation value;

[0103] In this embodiment, the target data refers to the fluid temperature input and output data and the expected temperature range of a key heat exchange component in the control system. These data are used to evaluate whether the current temperature deviates from the expected target value. The first deviation value is the difference obtained by comparing the actual fluid temperature of the target component with its expected temperature range, which indicates the degree of deviation between the actual temperature and the expected temperature. Based on the first deviation value, the system can calculate the corresponding flow control parameters, that is, adjust the fluid speed or flow rate to adjust the working state of the target component so that its temperature reaches the expected range. For example, if the temperature of the first-stage precooler 11 is too high, the system will adjust the liquid ammonia flow rate according to the deviation value to enhance the cooling effect and ensure the stability of the carbon dioxide temperature.

[0104] S502, calling the associated data of the associated component, the associated data including the expected temperature range of the associated component, the fluid temperature input and output data of the associated component, and the component attribute data;

[0105] In this embodiment, the associated data includes the working data and attribute data of other components associated with the target component. The associated components may be components that directly interact with or have an indirect impact on the target component, such as the liquid ammonia storage mechanism 3 or the carbon dioxide economizer 13. By calling the associated data of the associated components, the system can comprehensively consider the synergy and influence between multiple components and determine whether their temperature and flow rate need to be adjusted to ensure the stability of the entire heat exchange system. For example, the flow rate or temperature of the liquid ammonia storage mechanism 3 may affect the cooling effect of the primary precooler 11, so the associated data provides the flow control parameters and temperature data of the liquid ammonia storage mechanism 3 for optimization and adjustment.

[0106] S503, determining a corresponding second deviation value according to the expected temperature range of the associated component and the fluid temperature input and output data of the associated component;

[0107] In this embodiment, the second deviation value is calculated based on the difference between the actual temperature of the associated component and its expected temperature range, indicating the deviation between the actual working state of the associated component and the expected state. If the fluid temperature input and output data of the associated component exceeds its expected temperature range, the second deviation value will be large, indicating that the component is not working properly and may affect the heat exchange effect of the entire system. Therefore, the second deviation value is used to help determine whether the associated component needs to be further adjusted.

[0108] S504, determining an allowable adjustment threshold according to the component attribute data and the expected temperature range of the associated component;

[0109] In this embodiment, the allowable adjustment threshold is a maximum deviation value set by the system when designing the system according to the physical characteristics and working limits of the components. When the second deviation value exceeds this threshold, it means that the temperature of the associated component exceeds the adjustable range and measures must be taken to adjust it. For example, the adjustment range of the liquid ammonia flow rate may be limited by the maximum flow rate and pressure of the liquid ammonia storage tank 32. When the temperature deviation exceeds the allowable threshold, the system will increase the operating intensity of the cooling equipment or re-evaluate the fluid flow rate to avoid system failure or efficiency reduction.

[0110] S505: If the second deviation value exceeds the allowable adjustment threshold, determine the flow control parameter of the associated component according to the second deviation value.

[0111] In this embodiment, the determination of the flow control parameters is calculated based on the second deviation value and the preset flow control formula. The system will adjust the flow control parameters of the associated components according to the size of the deviation value to minimize the deviation value and ensure that the temperature of each component falls within the expected temperature range. For example, if the liquid ammonia flow fails to effectively cool the liquid carbon dioxide, resulting in a high temperature, the system will adjust the liquid ammonia flow according to the deviation value and increase the cooling amount of the liquid ammonia so that the temperature of the carbon dioxide gradually approaches the expected value, thereby restoring the normal operation of the heat exchange system. The preset flow control formula is usually formulated based on the principles of thermodynamics and fluid mechanics, according to the physical system and operating requirements of the actual application. This formula is mainly used to adjust the flow of the fluid according to the fluid temperature deviation (for example, the deviation between the expected temperature range and the actual temperature) to ensure that the heat exchange process achieves the best effect. The following are several possible compositions and implementation methods of the flow control formula, and the specific formula can be adjusted according to actual needs:

[0112] Relationship between flow and temperature deviation: The preset flow regulation formula may be based on the linear or nonlinear relationship between temperature deviation and flow. Assuming that the flow of the fluid is inversely proportional or proportional to the temperature deviation, it can be adjusted by the following formula:

[0113] Q = k × ΔT

[0114] Among them, Q represents the flow rate, ΔT represents the temperature deviation (i.e. the difference between the actual temperature and the expected temperature), and k is the proportional coefficient, which represents the adjustment sensitivity between the flow rate and the temperature change. By adjusting the coefficient k, the flow rate can be flexibly adjusted so that the temperature is kept within the target range as much as possible.

[0115] PID control formula based on system response: Another common regulation method is to use PID control strategy to adjust the flow rate in real time based on the error between the target temperature and the actual temperature. The PID controller formula is as follows:

[0116]

[0117] To ensure that the temperature is within the target range, we use the flow rate regulation formula to adjust the flow rate of liquid ammonia. Assume that the heat exchange relationship between liquid ammonia and carbon dioxide can be expressed by the following formula:

[0118] Q = k × ΔT

[0119] Temperature deviation calculation: Since the actual temperature of CO2 is -15°C and the target temperature is -20°C, the temperature deviation is: ΔT = 5°C;

[0120] Flow calculation: Assuming the flow ratio coefficient k is 2 (this coefficient can be adjusted according to the heat exchange efficiency of the system), the required liquid ammonia flow Q can be calculated as follows:

[0121] Q = 2 × 5 = 10 L / s

[0122] This means that in order to cool CO2 from 30°C to the target -20°C, the flow rate of liquid ammonia needs to be maintained at 10 liters per second.

[0123] Adjust flow rate: If the flow rate measured in the system does not match this calculated value (for example, the actual flow rate is 8 L / s), the flow control system will automatically increase the liquid ammonia flow rate to 10 L / s according to the flow adjustment formula. In this way, the flow rate of liquid ammonia is automatically adjusted according to the temperature deviation to ensure that the carbon dioxide reaches the target temperature.

[0124] Practical application: Assume that the system detects that the temperature deviation of carbon dioxide exceeds the preset allowable deviation range, for example, the deviation reaches 10°C instead of 5°C. At this time, the system will further increase the liquid ammonia flow to enhance the heat exchange effect, thereby reducing the carbon dioxide temperature to the target temperature range more quickly. The flow control system adjusts the flow through real-time feedback to avoid the temperature of carbon dioxide being too high or too low, thereby ensuring that the system operates in the best condition. It shows how to use the flow regulation formula to dynamically control the liquid ammonia flow and make precise adjustments according to the changes in carbon dioxide temperature to ensure the efficiency and stability of the heat exchange system.

[0125] In summary, the flow control parameters of the target component can be accurately calculated based on the deviation between the fluid temperature input and output data in the target data and the expected interval. By calling the relevant data of the associated components, the flow and temperature of each component can be accurately adjusted to ensure the coordinated work of each component in the system and the high efficiency of heat exchange. In the case where the deviation value exceeds the allowable adjustment threshold, the flow control parameters of the relevant components can be automatically adjusted to maintain the stability of the system, prevent failures or energy losses caused by improper flow or excessively high / low temperature, and significantly improve the control accuracy and overall operating efficiency of the system.

[0126] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A heat exchange system for precooling carbon dioxide using liquid ammonia, characterized in that: The heat exchange system for precooling carbon dioxide with liquid ammonia comprises a carbon dioxide precooling mechanism (1), a liquid ammonia heat exchange mechanism (2) and a liquid ammonia storage mechanism (3); The carbon dioxide input end of the carbon dioxide precooling mechanism (1) is used to receive the analyzed carbon dioxide. The first liquid ammonia input end of the carbon dioxide precooling mechanism (1) is connected to the first liquid ammonia output end of the liquid ammonia heat exchange mechanism (2) to receive the first-stage heat exchange liquid ammonia. The second liquid ammonia input end of the carbon dioxide precooling mechanism (1) is used to receive the second-stage heat exchange liquid ammonia. The liquid ammonia output end of the carbon dioxide precooling mechanism (1) is connected to the first liquid ammonia input end of the liquid ammonia heat exchange mechanism (2). The analyzed carbon dioxide is sequentially heat exchanged with the first-stage heat exchange liquid ammonia and the second-stage heat exchange liquid ammonia to generate and output corresponding liquid carbon dioxide. The first-stage heat exchange liquid ammonia generates corresponding ammonia to be burned after heat exchange, and the second-stage heat exchange liquid ammonia generates corresponding liquid ammonia to be cooled after heat exchange. The first liquid ammonia input end of the liquid ammonia heat exchange mechanism (2) is connected to the liquid ammonia output end of the carbon dioxide precooling mechanism (1) for receiving the liquid ammonia to be cooled. The second liquid ammonia input end of the liquid ammonia heat exchange mechanism (2) is connected to the liquid ammonia output end of the liquid ammonia storage mechanism (3) for receiving cold-keeping liquid ammonia. After the liquid ammonia to be cooled is heat-exchanged with the cold-keeping liquid ammonia, the liquid ammonia to be cooled is converted into cooled liquid ammonia and output to the liquid ammonia storage mechanism (3) through the second liquid ammonia output end of the liquid ammonia heat exchange mechanism (2). The cold-keeping liquid ammonia is converted into primary heat-exchange liquid ammonia and output to the carbon dioxide precooling mechanism (1) through the first liquid ammonia output end of the liquid ammonia heat exchange mechanism (2).

2. A heat exchange system for precooling carbon dioxide using liquid ammonia according to claim 1, characterized in that: The carbon dioxide precooling mechanism (1) comprises a primary precooler (11), a secondary precooler (12) and a liquefaction unit; The carbon dioxide input end of the primary precooler (11) is used to receive the carbon dioxide after the analysis, the liquid ammonia input end of the primary precooler (11) is connected to the first liquid ammonia output end of the liquid ammonia heat exchange mechanism (2) to receive the liquid ammonia for primary heat exchange, the carbon dioxide output end of the primary precooler (11) is connected to the carbon dioxide input end of the secondary precooler (12) to enable the secondary precooler (12) to receive the carbon dioxide after the primary heat exchange, and the ammonia output end of the primary precooler (11) is used to output the ammonia to be burned; The liquid ammonia input end of the liquefaction unit is used to receive the secondary heat exchange liquid ammonia, the liquid ammonia input end of the secondary precooler (12) is connected to the liquid ammonia output end of the liquefaction unit, so that the secondary precooler (12) receives the secondary heat exchange liquid ammonia, and the carbon dioxide output end of the secondary precooler (12) is connected to the carbon dioxide input end of the liquefaction unit, so that the liquefaction unit liquefies the carbon dioxide after the secondary heat exchange.

3. A heat exchange system for precooling carbon dioxide using liquid ammonia according to claim 2, characterized in that: The liquefaction unit comprises a carbon dioxide economizer (13) and a carbon dioxide cryocooler (14). The liquid ammonia input end of the carbon dioxide economizer (13) and the liquid ammonia input end of the carbon dioxide cryocooler (14) are both used to receive the secondary heat exchange liquid ammonia. The liquid ammonia output end of the carbon dioxide economizer (13) and the liquid ammonia output end of the carbon dioxide cryocooler (14) are both connected to the liquid ammonia input end of the secondary precooler (12). The carbon dioxide input end of the carbon dioxide economizer (13) is connected to the carbon dioxide output end of the secondary precooler (12). The carbon dioxide output end of the carbon dioxide economizer (13) is connected to the carbon dioxide input end of the carbon dioxide cryocooler (14). After successively passing through the cooling effect of the secondary heat exchange liquid ammonia in the carbon dioxide economizer (13) and the carbon dioxide cryocooler (14), the carbon dioxide after the secondary heat exchange is converted into liquid carbon dioxide. The carbon dioxide output end of the carbon dioxide cryocooler (14) is used to output the liquid carbon dioxide.

4. A heat exchange system for precooling carbon dioxide using liquid ammonia according to claim 3, characterized in that: The liquid ammonia input end of the carbon dioxide economizer (13) is connected to a first expansion valve (15), and the liquid ammonia input end of the carbon dioxide cryogenic refrigerator (14) is connected to a second expansion valve (16). Both the first expansion valve (15) and the second expansion valve (16) reduce the temperature of the secondary heat exchange liquid ammonia through expansion throttling, thereby reducing the temperature of the secondary heat exchange liquid ammonia to cool the carbon dioxide after the secondary heat exchange.

5. The heat exchange system for precooling carbon dioxide using liquid ammonia according to claim 1, characterized in that: The liquid ammonia heat exchange mechanism (2) comprises a water cooler (21), a primary ammonia heat exchanger (22) and a secondary ammonia heat exchanger (23); The liquid ammonia input end of the water cooler (21) is connected to the liquid ammonia output end of the carbon dioxide precooling mechanism (1), the liquid ammonia output end of the water cooler (21) is connected to the first liquid ammonia input end of the primary ammonia heat exchanger (22), the first liquid ammonia output end of the primary ammonia heat exchanger (22) is connected to the first liquid ammonia input end of the secondary ammonia heat exchanger (23), and the first liquid ammonia output end of the secondary ammonia heat exchanger (23) is connected to the liquid ammonia input end of the liquid ammonia storage mechanism (3); The liquid ammonia output end of the liquid ammonia storage mechanism (3) is connected to the second liquid ammonia input end of the secondary ammonia heat exchanger (23), the second liquid ammonia output end of the secondary ammonia heat exchanger (23) is connected to the second liquid ammonia input end of the primary ammonia heat exchanger (22), and the second liquid ammonia output end of the primary ammonia heat exchanger (22) is connected to the first liquid ammonia input end of the carbon dioxide precooling mechanism (1); The water cooler (21) is connected to a water cooling pipe, in which cooling water flows, and the first-level ammonia heat exchanger (22) and the second-level ammonia heat exchanger (23) are circulated with cold-keeping liquid ammonia output from the liquid ammonia storage mechanism (3). Under the cooling effect of the cooling water and the cold-keeping liquid ammonia in turn, the liquid ammonia to be cooled is converted into cooled liquid ammonia, and is transported to the liquid ammonia storage mechanism (3) through the first liquid ammonia output end of the second-level ammonia heat exchanger (23) for storage and cold preservation.

6. The heat exchange system for precooling carbon dioxide using liquid ammonia according to claim 1, characterized in that: The liquid ammonia storage mechanism (3) comprises a subcooler (31) and a liquid ammonia storage tank (32); the liquid ammonia input end of the subcooler (31) is connected to the second liquid ammonia output end of the liquid ammonia heat exchange mechanism (2); the liquid ammonia output end of the subcooler (31) is connected to the liquid ammonia input end of the liquid ammonia storage tank (32); and the liquid ammonia output end of the liquid ammonia storage tank (32) is connected to the second liquid ammonia input end of the liquid ammonia heat exchange mechanism (2); The subcooler (31) is connected to a first refrigeration pipe (33), and the refrigerant flowing in the first refrigeration pipe (33) is used to perform primary refrigeration insulation on the cooled liquid ammonia. The liquid ammonia storage tank (32) is connected to a second refrigeration pipe (34), and the second refrigeration pipe (34) is provided with a flowing refrigerant to perform secondary refrigeration insulation on the cooled liquid ammonia after primary refrigeration insulation, thereby converting it into refrigerated liquid ammonia, and outputting the refrigerated liquid ammonia through the liquid ammonia output end of the liquid ammonia storage tank (32).

7. A heat exchange system for precooling carbon dioxide using liquid ammonia according to claim 6, characterized in that: A liquid ammonia discharge pipeline liquid level regulating valve group (35) is provided between the liquid ammonia output end of the liquid ammonia storage tank (32) and the second liquid ammonia input end of the liquid ammonia heat exchange mechanism (2).

8. A heat exchange system for precooling carbon dioxide using liquid ammonia according to claim 7, characterized in that: A liquid ammonia delivery pump (36) is provided between the liquid ammonia discharge pipeline liquid level regulating valve group (35) and the second liquid ammonia input end of the liquid ammonia heat exchange mechanism (2).

9. A control method for a heat exchange system for precooling carbon dioxide using liquid ammonia, applied to a heat exchange system for precooling carbon dioxide using liquid ammonia as claimed in any one of claims 1 to 8, characterized in that: The control method comprises: Acquire a heat exchange path of interest, and determine a component of interest and an association relationship between each component of interest according to the heat exchange path of interest; Determine an expected temperature interval of the component of interest, wherein the expected temperature interval includes an expected fluid input temperature interval and an expected fluid output temperature interval; Acquiring fluid temperature input and output data of the component of interest; Determine whether the temperature input and output data fall within the corresponding expected temperature range, and if so, add or maintain the corresponding visualization feature in the constructed visualization platform; If not, determine that the component of interest is the target component, determine the fluid temperature input and output data and the expected temperature range as target data, and determine the associated component corresponding to the target component based on the association relationship, call the associated data of the associated component, determine whether the associated components are both target components based on the associated data, determine the corresponding flow control parameters based on the target data, and the flow control parameters are used to adjust the fluid speed in the component of interest and the target component.

10. The control method of a heat exchange system for precooling carbon dioxide with liquid ammonia according to claim 9, characterized in that: The steps of calling the associated data of the associated component, determining whether the associated component is the same as the target component according to the associated data, and determining the corresponding flow control parameter according to the target data include: Determine a corresponding first deviation value according to the fluid temperature input and output data and the expected temperature range in the target data, and determine a flow control parameter of the target component according to the first deviation value; Calling the associated data of the associated component, the associated data including the expected temperature range of the associated component, the fluid temperature input and output data of the associated component, and component attribute data; Determining a corresponding second deviation value according to the expected temperature range of the associated component and the fluid temperature input and output data of the associated component; Determining an allowable adjustment threshold value according to the component attribute data and the expected temperature range of the associated component; If the second deviation value exceeds the allowable adjustment threshold, the flow control parameter of the associated component is determined according to the second deviation value.

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