Flue gas waste heat utilization system

Abstract

The utility model provides a flue gas waste heat utilization system. The flue gas waste heat utilization system comprises a waste heat boiler, an inlet buffer tank, an outlet buffer tank, a heat storage system and a heat utilization system, the waste heat boiler comprises a flue gas flow channel and a heat exchange part arranged in the flue gas flow channel, and the heat exchange part is used for transferring heat energy in flue gas into a heat storage medium in the heat exchange part; a low-temperature heat storage medium output end of the heat storage system is connected with an input end of the inlet buffer tank, an output end of the inlet buffer tank is connected with an input end of the heat exchange part, an output end of the heat exchange part is connected with an input end of the outlet buffer tank, and an output end of the outlet buffer tank is connected with a high-temperature heat storage medium input end of the heat storage system; the high-temperature heat storage medium output end of the heat storage system is connected with the input end of the heat using system, and the output end of the heat using system is connected with the low-temperature heat storage medium input end of the heat storage system. According to the scheme, the heat in the smoke can be stored and released when a user needs, so that the smoke heat can be fully utilized, and energy waste is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas waste heat utilization, and in particular to a flue gas waste heat utilization system. Background Art

[0002] At present, in the field of flue gas waste heat recovery, conventional waste heat boilers are usually used for heat recovery. The waste heat boiler uses the high-temperature steam generated by the flue gas waste heat to drive the steam turbine to generate power or provide heating for users. However, since the heat energy in high-temperature steam cannot be stored for a long time, the high-temperature steam generated by the waste heat boiler needs to be used immediately to generate power or provide heating for users. When the user has no electricity or heat demand in a certain period of time, the high-temperature steam output by the waste heat boiler will be difficult to be normally consumed, which is easy to cause waste. Utility Model Content

[0003] In view of the defects in the prior art, the purpose of the utility model is to provide a flue gas waste heat utilization system, which can store the heat in the flue gas and release the heat when the user needs it, thereby making full use of the flue gas heat and avoiding energy waste.

[0004] The utility model provides a flue gas waste heat utilization system, comprising a waste heat boiler, an inlet buffer tank, an outlet buffer tank, a heat storage system and a heat utilization system;

[0005] The waste heat boiler comprises a flue gas flow passage and a heat exchange part arranged in the flue gas flow passage, wherein the heat exchange part is used to transfer heat energy in the flue gas to the heat storage medium in the heat exchange part;

[0006] The low-temperature heat storage medium output end of the heat storage system is connected to the low-temperature heat storage medium input end of the inlet buffer tank, the low-temperature heat storage medium output end of the inlet buffer tank is connected to the low-temperature heat storage medium input end of the heat exchange unit through a first pipeline, the high-temperature heat storage medium output end of the heat exchange unit is connected to the high-temperature heat storage medium input end of the outlet buffer tank, and the high-temperature heat storage medium output end of the outlet buffer tank is connected to the high-temperature heat storage medium input end of the heat storage system through a second pipeline; wherein a first valve assembly is provided on the first pipeline, and a second valve assembly is provided on the second pipeline;

[0007] The high-temperature heat storage medium output end of the heat storage system is connected to the high-temperature heat storage medium input end of the heat-using system, and the low-temperature heat storage medium output end of the heat-using system is connected to the low-temperature heat storage medium input end of the heat storage system.

[0008] Furthermore, it also includes a compressed gas system, wherein a compressed gas output end of the compressed gas system is connected to a compressed gas input end of the inlet buffer tank through a third pipeline, and a third valve assembly is arranged on the third pipeline.

[0009] Furthermore, it also includes a drainage device, the heat storage medium input end of the drainage device is connected to the low-temperature heat storage medium input end of the heat exchange part through a fifth pipeline, and a fifth valve assembly is arranged on the fifth pipeline.

[0010] Furthermore, the compressed gas output end of the compressed gas system is also connected to the compressed gas input end of the outlet buffer tank through a fourth pipeline, and a fourth valve assembly is provided on the fourth pipeline.

[0011] Furthermore, the inlet buffer tank is provided with an inlet buffer tank liquid level gauge, and the outlet buffer tank is provided with an outlet buffer tank liquid level gauge.

[0012] Furthermore, the heat storage system includes a low-temperature heat storage unit for storing a low-temperature heat storage medium and a high-temperature heat storage unit for storing a high-temperature heat storage medium.

[0013] Furthermore, the low-temperature heat storage medium in the heat storage system is output to the outside through a low-temperature heat storage medium delivery pump assembly, and the low-temperature heat storage medium delivery pump assembly includes a first low-temperature heat storage medium delivery pump and a second low-temperature heat storage medium delivery pump, and the first low-temperature heat storage medium delivery pump and the second low-temperature heat storage medium delivery pump are backup for each other.

[0014] Furthermore, the heat utilization system includes a heat exchange system and a steam turbine generator set, and the heat exchange system is used to transfer heat in the high-temperature heat storage medium to the water working medium, thereby generating high-temperature and high-pressure steam to drive the operation of the steam turbine generator set.

[0015] Furthermore, the heat storage system adopts a molten salt heat storage system or a thermal oil heat storage system.

[0016] Compared with the prior art, the utility model has the following beneficial effects:

[0017] 1. In the flue gas waste heat utilization system provided by the utility model, by setting up a heat storage system (such as a molten salt heat storage system), the heat storage medium (such as molten salt) can be used to absorb and store the flue gas heat energy in the flue gas flow duct of the waste heat boiler, and when the heat system needs it, the heat energy stored in the heat storage system (such as a molten salt heat storage system) is released to the heat system for utilization, thereby avoiding the waste of heat energy in the flue gas.

[0018] 2. Since flue gas is the waste gas discharged during the factory production process, and there is a large difference in electricity prices between peak and valley periods in the city electricity, in the flue gas waste heat utilization system of the utility model, the heat-using system is set as a power generation system including a heat exchange system and a steam turbine generator set, so that the city electricity can be used to maintain the normal operation of the factory during the valley period, and the flue gas waste heat produced during the valley period is stored in a heat storage system (such as a molten salt heat storage system), and the heat energy stored in the heat storage system (such as a molten salt heat storage system) is released to the heat-using system during the peak period, so that the heat-using system outputs electrical energy for the factory to use, which can take advantage of the difference in peak and valley electricity prices and effectively reduce the operating costs during the factory production process.

[0019] 3. In the present invention, by setting an inlet buffer tank and a compressed gas system, when the flue gas waste heat utilization system is operating normally, the pressure in the inlet buffer tank can be adjusted, thereby realizing the control of the flow rate of the heat storage medium (such as molten salt) in the waste heat boiler; when the first low-temperature heat storage medium delivery pump and the second low-temperature heat storage medium delivery pump in the low-temperature heat storage medium delivery pump assembly are switched, the heat storage system cannot deliver the low-temperature heat storage medium to the waste heat boiler. At this time, the compressed gas system is used to drive the low-temperature heat storage medium (such as low-temperature molten salt) in the inlet buffer tank to the heat exchange part of the waste heat boiler, thereby avoiding overheating of the heat exchange part of the waste heat boiler and improving the safety and reliability of the entire system. By setting an outlet buffer tank, a buffer space can be provided for the heat storage medium (such as molten salt) output from the heat exchange part of the waste heat boiler, preventing the heat storage medium (such as molten salt) in the waste heat boiler from being blocked due to the blockage of the heat storage medium delivery pipeline (such as the molten salt delivery pipeline), resulting in overheating and damage to the heat exchange part, and even production accidents.

[0020] 4. For heat storage media with a high freezing point (such as molten salt), when the waste heat boiler is shut down or the flue gas temperature is low, the heat storage medium (such as molten salt) in the waste heat boiler needs to be discharged to prevent the heat storage medium (such as molten salt) from solidifying in the waste heat boiler due to the temperature drop, causing the heat exchange tubes in the heat exchange part of the waste heat boiler to freeze and block. The utility model provides a discharge device at the low-temperature heat storage medium input end of the heat exchange part of the waste heat boiler, so that the heat storage medium (such as molten salt) in the waste heat boiler can be discharged from the waste heat boiler when the waste heat boiler is shut down or the flue gas temperature is low. Furthermore, by connecting the compressed gas output end of the compressed gas system with the compressed gas input end of the outlet buffer tank, when the heat storage medium (such as molten salt) in the waste heat boiler needs to be discharged, the outlet buffer tank is pressurized by using the compressed gas system, which can accelerate the discharge rate of the heat storage medium (such as molten salt) and further prevent the heat storage medium (such as molten salt) from freezing. At the same time, by purging the heat exchange part of the waste heat boiler with compressed gas, the residue of the heat storage medium (such as molten salt) in the heat exchange part of the waste heat boiler can be reduced or avoided.

[0021] 5. The utility model provides an inlet buffer tank level gauge and an outlet buffer tank level gauge. On the one hand, it can determine whether the liquid levels of the heat storage medium (such as molten salt) in the inlet buffer tank and the outlet buffer tank meet the preset requirements. On the other hand, when the flue gas waste heat utilization system operates normally and stably, the liquid levels of the heat storage medium (such as molten salt) in the inlet buffer tank and the outlet buffer tank are basically kept stable. When the heat exchange tubes in the heat exchange part of the waste heat boiler burst and leak, the liquid levels of the heat storage medium (such as molten salt) in the inlet buffer tank and the outlet buffer tank will drop rapidly. Therefore, by providing the inlet buffer tank level gauge and the outlet buffer tank level gauge, it can be detected whether the heat exchange tubes in the heat exchange part of the waste heat boiler burst. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0023] Figure 1 A structural schematic diagram of a flue gas waste heat utilization system provided in an embodiment of the utility model.

[0024] In the figure:

[0025] 1. Low-temperature molten salt tank; 2. Low-temperature molten salt pump; 3. Inlet buffer tank; 4. Waste heat boiler; 5. Outlet buffer tank; 6. High-temperature molten salt tank; 7. Compressed gas system; 8. Fourth valve assembly; 9. Third valve assembly; 10. Salt drainage tank; 11. High-temperature molten salt pump; 12. First pipeline; 13. Second pipeline; 14. First valve assembly; 15. Second valve assembly; 16. Third pipeline; 17. Fourth pipeline; 18. Fifth pipeline; 19. Heat system; 20. Fifth valve assembly; 21. Inlet buffer tank level gauge; 22. Outlet buffer tank level gauge; 23. Flue gas flow duct; 24. Heat exchange unit. DETAILED DESCRIPTION

[0026] The utility model is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the utility model, but do not limit the utility model in any form. It should be pointed out that for those of ordinary skill in the art, several changes and improvements can be made without departing from the concept of the utility model. These all belong to the protection scope of the utility model.

[0027] Example:

[0028] See also Figure 1 , a flue gas waste heat utilization system provided in an embodiment of the present application includes a waste heat boiler 4, an inlet buffer tank 3, an outlet buffer tank 5, a heat storage system and a heat utilization system 19;

[0029] The waste heat boiler 4 includes a flue gas flow channel 23 and a heat exchange portion 24 disposed in the flue gas flow channel 23, and the heat exchange portion 24 is used to transfer heat energy in the flue gas to the heat storage medium in the heat exchange portion 24;

[0030] The low-temperature heat storage medium output end of the heat storage system is connected to the low-temperature heat storage medium input end of the inlet buffer tank 3, the low-temperature heat storage medium output end of the inlet buffer tank 3 is connected to the low-temperature heat storage medium input end of the heat exchange part 24 through the first pipeline 12, the high-temperature heat storage medium output end of the heat exchange part 24 is connected to the high-temperature heat storage medium input end of the outlet buffer tank 5, and the high-temperature heat storage medium output end of the outlet buffer tank 5 is connected to the high-temperature heat storage medium input end of the heat storage system through the second pipeline 13; wherein, a first valve assembly 14 is provided on the first pipeline 12, and a second valve assembly 15 is provided on the second pipeline 13;

[0031] The high temperature heat storage medium output end of the heat storage system is connected to the high temperature heat storage medium input end of the heat using system 19, and the low temperature heat storage medium output end of the heat using system 19 is connected to the low temperature heat storage medium input end of the heat storage system.

[0032] By setting up a heat storage system, the heat storage medium can be used to absorb and store the flue gas thermal energy in the flue gas flow duct 23 of the waste heat boiler 4, and the thermal energy stored in the heat storage system can be released to the heat using system 19 for use when needed by the heat using system 19, thereby avoiding the waste of thermal energy in the flue gas.

[0033] In a specific embodiment, the heat storage system includes a low-temperature heat storage unit for storing a low-temperature heat storage medium and a high-temperature heat storage unit for storing a high-temperature heat storage medium; the low-temperature heat storage medium output end of the low-temperature heat storage unit is connected to the low-temperature heat storage medium input end of the inlet buffer tank 3 through a first connecting pipeline, and a low-temperature heat storage medium delivery pump assembly is provided on the first connecting pipeline, and the low-temperature heat storage medium delivery pump assembly is used to output the low-temperature heat storage medium in the low-temperature heat storage unit; the high-temperature heat storage medium output end of the high-temperature heat storage unit is connected to the high-temperature heat storage medium input end of the heat using system 19 through a second connecting pipeline, and a high-temperature heat storage medium delivery pump assembly is provided on the second connecting pipeline, and the high-temperature heat storage medium delivery pump assembly is used to output the high-temperature heat storage medium in the high-temperature heat storage unit.

[0034] Specifically, the high-temperature heat storage medium delivery pump assembly adopts a high-temperature heat storage medium delivery pump, and the low-temperature heat storage medium delivery pump assembly includes a first low-temperature heat storage medium delivery pump and a second low-temperature heat storage medium delivery pump, and the first low-temperature heat storage medium delivery pump and the second low-temperature heat storage medium delivery pump are backup for each other.

[0035] In a specific embodiment, the flue gas waste heat utilization system also includes a compressed gas system 7, the compressed gas output end of the compressed gas system 7 is connected to the compressed gas input end of the inlet buffer tank 3 through a third pipeline 16, and a third valve assembly 9 is provided on the third pipeline 16.

[0036] When the flue gas waste heat utilization system is operating normally, the compressed gas system 7 can adjust the pressure in the inlet buffer tank 3, thereby realizing the control of the flow rate of the heat storage medium in the waste heat boiler 4; during the switching of the first low-temperature heat storage medium delivery pump and the second low-temperature heat storage medium delivery pump in the low-temperature heat storage medium delivery pump assembly (the low-temperature heat storage medium delivery pump originally in the working state stops running due to a fault or other reasons, so it is necessary to convert the low-temperature heat storage medium delivery pump originally in the standby state to the working state), the heat storage system cannot deliver the low-temperature heat storage medium to the waste heat boiler, and the compressed gas system 7 is used to drive the low-temperature heat storage medium in the inlet buffer tank 3 to the heat exchange part 24 of the waste heat boiler 4, thereby avoiding the overheating of the heat exchange part 24 of the waste heat boiler 4, and improving the safety and reliability of the entire system. Optionally, the compressed gas system 7 can adopt a compressed air system.

[0037] In a specific embodiment, the flue gas waste heat utilization system also includes a discharge device, the heat storage medium input end of the discharge device is connected to the low-temperature heat storage medium input end of the heat exchange part 24 through a fifth pipeline 18, and a fifth valve assembly 20 is provided on the fifth pipeline 18.

[0038] Since the heat storage medium usually uses a medium with a higher freezing point, however, for the heat storage medium with a higher freezing point, when the waste heat boiler 4 is shut down or the flue gas temperature is low, the heat storage medium in the waste heat boiler 4 needs to be discharged to prevent the heat storage medium from solidifying in the waste heat boiler 4 due to the temperature drop, causing the heat exchange pipes in the heat exchange part 24 of the waste heat boiler 4 to be frozen and blocked. Therefore, by providing a evacuation device at the low-temperature heat storage medium input end of the heat exchange part 24 of the waste heat boiler 4, it is convenient to discharge the heat storage medium in the waste heat boiler 4 from the waste heat boiler 4 when the waste heat boiler 4 is shut down or the flue gas temperature is low, and by providing the fifth valve assembly 20, it is prevented from accidentally flowing into the evacuation device during the process of the low-temperature heat storage medium flowing from the inlet buffer tank 3 into the heat exchange part 24.

[0039] Preferably, the compressed gas output end of the compressed gas system 7 is also connected to the compressed gas input end of the outlet buffer tank 5 through a fourth pipeline 17 , and a fourth valve assembly 8 is provided on the fourth pipeline 17 .

[0040] By connecting the compressed gas output end of the compressed gas system 7 with the compressed gas input end of the outlet buffer tank 5, when the heat storage medium in the waste heat boiler 4 needs to be discharged, the outlet buffer tank 5 is pressurized by the compressed gas system 7, which can speed up the discharge rate of the heat storage medium and further prevent the heat storage medium from freezing. At the same time, by purging the heat exchange part 24 of the waste heat boiler 4 with compressed gas, the residual heat storage medium in the heat exchange part 24 of the waste heat boiler 4 can be reduced or avoided.

[0041] In a specific embodiment, an inlet buffer tank liquid level meter 21 is provided on the inlet buffer tank 3 , and an outlet buffer tank liquid level meter 22 is provided on the outlet buffer tank 5 .

[0042] By setting the inlet buffer tank level gauge 21 and the outlet buffer tank level gauge 22, on the one hand, it is possible to determine whether the heat storage medium levels in the inlet buffer tank 3 and the outlet buffer tank 5 meet the preset requirements. On the other hand, when the flue gas waste heat utilization system is operating normally and stably, the heat storage medium levels in the inlet buffer tank 3 and the outlet buffer tank 5 are basically kept stable. When the heat exchange tubes in the heat exchange part 24 of the waste heat boiler 4 burst and leak, the heat storage medium levels in the inlet buffer tank 3 and the outlet buffer tank 5 will drop rapidly. Therefore, by setting the inlet buffer tank level gauge 21 and the outlet buffer tank level gauge 22, it is possible to detect whether the heat exchange tubes in the heat exchange part 24 of the waste heat boiler 4 burst.

[0043] In a specific embodiment, the heat utilization system 19 includes a heat exchange system and a steam turbine generator set. The heat exchange system is used to transfer heat in the high-temperature heat storage medium to the water working medium, thereby generating high-temperature and high-pressure steam to drive the operation of the steam turbine generator set.

[0044] Since flue gas is the waste gas discharged during the factory production process, and there is a large difference in electricity prices between peak and valley periods, by setting the heat system 19 to a power generation system including a heat exchange system and a steam turbine generator set, the city electricity can be used to maintain the normal operation of the factory during the valley period, and the waste heat of the flue gas produced during the valley period is stored in the heat storage system, and the heat energy stored in the heat storage system is released to the heat system 19 during the peak period, so that the heat system 19 outputs electrical energy for the factory to use. The difference in peak and valley electricity prices can be used to effectively reduce the operating costs of the factory during the production process.

[0045] In a specific embodiment, the heat storage system adopts a molten salt heat storage system or a heat transfer oil heat storage system; preferably a molten salt heat storage system. Molten salt refers to a melt of one, two or more salt compounds, and the heat storage performance of the molten salt needs to meet the requirements of the heat storage system for the heat storage temperature range, stability and other aspects of the molten salt. Specifically, in this embodiment, the molten salt is a melt of a mixture of sodium nitrate and potassium nitrate. Of course, in other embodiments, the molten salt can also be a suitable salt thereof.

[0046] In a specific implementation scenario, the heat storage system adopts a molten salt heat storage system, the heat storage medium adopts molten salt, the low-temperature heat storage unit is a low-temperature molten salt tank 1, the first low-temperature heat storage medium delivery pump and the second low-temperature heat storage medium delivery pump are two low-temperature molten salt pumps 2 that are standby for each other, the high-temperature heat storage unit is a high-temperature molten salt tank 6, the drainage device is a salt drainage tank 10, and the high-temperature heat storage medium delivery pump assembly is a high-temperature molten salt pump 11. The operation process of this flue gas waste heat utilization system is as follows:

[0047] During the heat storage stage, the third valve assembly 9, the first valve assembly 14, and the second valve assembly 15 are opened, the fourth valve assembly 8 and the fifth valve assembly 20 are closed, and the compressed gas system 7 (the compressed gas system 7 can be a compressed air system) maintains the pressure in the inlet buffer tank 3 to meet the preset operating requirements. The low-temperature molten salt pump 2 transports the low-temperature molten salt in the low-temperature molten salt tank 1 to the inlet buffer tank 3, and then the low-temperature molten salt enters the heat exchange part 24 of the waste heat boiler 4 from the inlet buffer tank 3, and exchanges heat with the high-temperature flue gas in the flue gas flow duct 23 of the waste heat boiler 4, so that the heat energy in the high-temperature flue gas is transferred to the molten salt. After heat exchange, the low-temperature molten salt is heated to high-temperature molten salt and enters the outlet buffer tank 5. The high-temperature molten salt flows from the outlet buffer tank 5 into the high-temperature molten salt tank 6 for storage.

[0048] In the heat release stage, the high-temperature molten salt pump 11 transports the high-temperature molten salt in the high-temperature molten salt tank 6 to the heat using system 19 . After releasing heat in the heat using system 19 , the high-temperature molten salt is converted into low-temperature molten salt and transported back to the low-temperature molten salt tank 1 .

[0049] During the salt drainage stage, the low-temperature molten salt pump 2 stops, the third valve assembly 9 is closed, the fourth valve assembly 8 is opened, and compressed air enters the outlet buffer tank 5. Under the action of gravity and in combination with the compressed air purge, the molten salt in the heat exchange tubes of the heat exchange part 24 is urgently evacuated to the salt drainage tank 10 to prevent the low-temperature molten salt from condensing and freezing in the heat exchange tubes of the heat exchange part 24.

[0050] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other at will.

Claims

1. A flue gas waste heat utilization system, characterized in that: It comprises a waste heat boiler (4), an inlet buffer tank (3), an outlet buffer tank (5), a heat storage system and a heat utilization system (19); The waste heat boiler (4) comprises a flue gas flow passage (23) and a heat exchange portion (24) arranged in the flue gas flow passage (23), wherein the heat exchange portion (24) is used to transfer heat energy in the flue gas to a heat storage medium in the heat exchange portion (24); The low-temperature heat storage medium output end of the heat storage system is connected to the low-temperature heat storage medium input end of the inlet buffer tank (3); the low-temperature heat storage medium output end of the inlet buffer tank (3) is connected to the low-temperature heat storage medium input end of the heat exchange part (24) through a first pipeline (12); the high-temperature heat storage medium output end of the heat exchange part (24) is connected to the high-temperature heat storage medium input end of the outlet buffer tank (5); the high-temperature heat storage medium output end of the outlet buffer tank (5) is connected to the high-temperature heat storage medium input end of the heat storage system through a second pipeline (13); wherein a first valve assembly (14) is provided on the first pipeline (12), and a second valve assembly (15) is provided on the second pipeline (13); The high-temperature heat storage medium output end of the heat storage system is connected to the high-temperature heat storage medium input end of the heat-using system (19), and the low-temperature heat storage medium output end of the heat-using system (19) is connected to the low-temperature heat storage medium input end of the heat storage system.

2. A flue gas waste heat utilization system according to claim 1, characterized in that: It also comprises a compressed gas system (7), wherein the compressed gas output end of the compressed gas system (7) is connected to the compressed gas input end of the inlet buffer tank (3) via a third pipeline (16), and a third valve assembly (9) is provided on the third pipeline (16).

3. A flue gas waste heat utilization system according to claim 2, characterized in that: It also comprises a discharge device, the heat storage medium input end of the discharge device is connected to the low-temperature heat storage medium input end of the heat exchange part (24) through a fifth pipeline (18), and a fifth valve assembly (20) is provided on the fifth pipeline (18).

4. A flue gas waste heat utilization system according to claim 3, characterized in that: The compressed gas output end of the compressed gas system (7) is also connected to the compressed gas input end of the outlet buffer tank (5) via a fourth pipeline (17), and a fourth valve assembly (8) is provided on the fourth pipeline (17).

5. The flue gas waste heat utilization system according to claim 1, characterized in that: The inlet buffer tank (3) is provided with an inlet buffer tank liquid level meter (21), and the outlet buffer tank (5) is provided with an outlet buffer tank liquid level meter (22).

6. The flue gas waste heat utilization system according to claim 1, characterized in that: The heat storage system includes a low-temperature heat storage unit for storing a low-temperature heat storage medium and a high-temperature heat storage unit for storing a high-temperature heat storage medium.

7. The flue gas waste heat utilization system according to claim 2, characterized in that: The low-temperature heat storage medium in the heat storage system is output to the outside through a low-temperature heat storage medium delivery pump assembly, and the low-temperature heat storage medium delivery pump assembly includes a first low-temperature heat storage medium delivery pump and a second low-temperature heat storage medium delivery pump, and the first low-temperature heat storage medium delivery pump and the second low-temperature heat storage medium delivery pump are backup for each other.

8. The flue gas waste heat utilization system according to claim 1, characterized in that: The heat utilization system (19) comprises a heat exchange system and a steam turbine generator set, wherein the heat exchange system is used to transfer heat in a high-temperature heat storage medium to a water working medium, thereby generating high-temperature and high-pressure steam to drive the operation of the steam turbine generator set.

9. A flue gas waste heat utilization system according to any one of claims 1 to 8, characterized in that: The heat storage system adopts a molten salt heat storage system or a thermal oil heat storage system.

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