Flue gas waste heat recovery combined with multi-stage distillation seawater desalination system for deep peak shaving

Abstract

This invention provides a multi-stage distillation seawater desalination system with flue gas waste heat recovery for deep peak shaving, comprising a power generation system and a seawater desalination subsystem. The power generation system includes a boiler, a turbine unit, and a cryogenic economizer. The boiler's steam outlet is connected to the turbine unit's steam inlet, the turbine unit's steam outlet is connected to the boiler's liquid inlet, and the boiler's flue gas outlet is connected to the cryogenic economizer's flue gas inlet. The seawater desalination subsystem includes a multi-stage flash chamber. The cryogenic economizer's seawater outlet is connected to the multi-stage flash chamber's seawater inlet, the multi-stage flash chamber's steam outlet is connected to the cryogenic economizer's return water inlet, the turbine unit is connected to the multi-stage flash chamber, the multi-stage flash chamber's freshwater outlet is used to output freshwater, and the cryogenic economizer has a seawater inlet for inputting seawater. This system reduces energy consumption during seawater desalination, improves the overall efficiency of the seawater desalination subsystem, and deepens the peak shaving depth of the power generation system.

Description

Technical Field

[0001] This invention belongs to the field of waste heat utilization technology in power generation systems, specifically relating to a combined multi-stage distillation and seawater desalination system for deep peak shaving and flue gas waste heat recovery. Background Technology

[0002] Existing coal-fired power plants face several problems, including significant cold source losses, high energy consumption in seawater desalination processes, and pollution from concentrated brine discharge. Traditional seawater desalination technologies typically use a single heat source (such as steam extracted from a steam turbine) to drive low-temperature multi-effect distillation or reverse osmosis processes, but these suffer from drawbacks such as low waste heat utilization, severe membrane fouling, and high costs associated with concentrated brine treatment. Furthermore, flue gas waste heat and other waste heat are not effectively utilized, thus limiting the efficiency of energy recovery and comprehensive utilization.

[0003] Therefore, there is an urgent need for a freshwater desalination system that can improve the utilization rate of waste heat from power generation systems. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art, and to provide a flue gas waste heat recovery combined with multi-stage distillation seawater desalination system for deep peak shaving.

[0005] This invention provides a combined multi-stage distillation and seawater desalination system for deep peak shaving, comprising an electron generation system and a seawater desalination subsystem; The power generation system includes: a boiler, a steam turbine unit, and a low-temperature economizer. The steam outlet of the boiler is connected to the steam inlet of the steam turbine unit, the steam outlet of the steam turbine unit is connected to the liquid inlet of the boiler, and the flue gas outlet of the boiler is connected to the flue gas inlet of the low-temperature economizer. The seawater desalination subsystem includes a multi-stage flash chamber. The seawater outlet of the low-temperature economizer is connected to the seawater inlet of the multi-stage flash chamber. The steam outlet of the multi-stage flash chamber is connected to the return water inlet of the low-temperature economizer. The steam turbine unit is connected to the multi-stage flash chamber. The freshwater outlet of the multi-stage flash chamber is used to output freshwater. The low-temperature economizer has a seawater inlet for inputting seawater.

[0006] In some embodiments of the present invention, the multi-stage flash chamber includes a first flash chamber, a second flash chamber, a third flash chamber, and a fourth flash chamber connected in sequence. The seawater outlet of the low-temperature economizer is connected to the seawater inlet of the first flash chamber, and the steam outlet of the fourth flash chamber is connected to the return water inlet of the low-temperature economizer.

[0007] In some embodiments of the present invention, the seawater desalination subsystem further includes: a steam ejector, wherein a first inlet of the steam ejector is connected to the turbine unit, a second inlet of the steam ejector is connected to the steam outlet of the second flash chamber, and an ejection outlet of the steam ejector is connected to the steam inlet of the first flash chamber.

[0008] In some embodiments of the present invention, the seawater desalination subsystem further includes a freshwater storage tank connected to the freshwater outlet of each of the multi-stage flash chambers.

[0009] In some embodiments of the present invention, the power generation system further includes an air preheater, the hot-side inlet of which is connected to the flue gas outlet of the boiler, and the hot-side outlet of which is connected to the flue gas inlet of the low-temperature economizer.

[0010] In some embodiments of the present invention, the steam turbine unit includes a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, and a generator connected in sequence. The steam outlet of the boiler is connected to the high-pressure cylinder and the intermediate-pressure cylinder, the intermediate-pressure cylinder is connected to the low-pressure cylinder, and the steam outlets of the high-pressure cylinder, the intermediate-pressure cylinder, and the low-pressure cylinder are respectively connected to the liquid inlet of the boiler.

[0011] In some embodiments of the present invention, the intermediate-pressure cylinder is connected to the seawater desalination subsystem.

[0012] In some embodiments of the present invention, the power generation system further includes a condenser, a first low-pressure heater, a second low-pressure heater, a deaerator, a first high-pressure heater, and a second high-pressure heater connected in sequence. The condenser is connected to the steam outlet of the low-pressure cylinder, the inlet of the first low-pressure heater is connected to the first steam outlet of the low-pressure cylinder, the inlet of the second low-pressure heater is connected to the first steam outlet of the intermediate-pressure cylinder, the inlet of the deaerator is connected to the extraction steam outlet of the intermediate-pressure cylinder, the inlet of the first high-pressure heater is connected to the second steam outlet of the intermediate-pressure cylinder, the inlet of the second high-pressure heater is connected to the steam outlet of the high-pressure cylinder, and the steam outlet of the second high-pressure heater is connected to the liquid inlet of the boiler.

[0013] In some embodiments of the present invention, the flue gas temperature at the flue gas inlet of the low-temperature economizer is 140°C to 180°C, and the flue gas temperature at the flue gas outlet of the low-temperature economizer is 85°C to 100°C.

[0014] In some embodiments of the present invention, the seawater temperature at the seawater inlet of the low-temperature economizer is 20°C to 30°C, and the seawater temperature at the seawater outlet of the low-temperature economizer is 75°C to 90°C.

[0015] This invention relates to a flue gas waste heat recovery combined with multi-stage distillation seawater desalination system for deep peak shaving. By utilizing boiler waste heat in a cascade manner, the system transfers the boiler's waste heat energy to the seawater desalination process, thereby reducing energy consumption during desalination. High-temperature steam is extracted from the turbine unit and mixed with low-temperature steam in the seawater desalination subsystem, directly inputting it into the desalination subsystem. This improves the overall efficiency of the seawater desalination subsystem and deepens the peak shaving depth of the power generation system. Under varying power plant load conditions, the system rationally allocates energy, ensuring synergistic optimization of power generation, water production, and resource recovery, thus improving the system's economic efficiency and environmental friendliness. The system provided by this invention has high-efficiency heat recovery capabilities and multi-stage co-production effects, enabling stable operation and ensuring efficient water resource production even under significant power plant load variations. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the flue gas waste heat recovery combined with multi-stage distillation seawater desalination system for deep peak shaving according to the present invention. Figure 2 The graph shows the variation of flue gas temperature and seawater temperature at the outlet of the low-temperature economizer of the present invention with load.

[0017] The labels in the attached diagram are as follows: 1. Boiler; 2. Air preheater; 3. Low-temperature economizer; 4. High-pressure cylinder; 5. Medium-pressure cylinder; 6. Low-pressure cylinder; 7. Generator; 8. Condenser; 9. First low-pressure heater; 10. Second low-pressure heater; 11. Deaerator; 12. First high-pressure heater; 13. Second high-pressure heater; 14. Steam ejector; 15. First flash chamber; 16. Second flash chamber; 17. Third flash chamber; 18. Fourth flash chamber; 19. Freshwater storage tank. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the invention. The described embodiments are some, but not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0019] like Figure 1As shown, this embodiment of the invention provides a multi-stage distillation seawater desalination system for deep peak shaving, comprising a power generation system and a seawater desalination subsystem. Specifically, the power generation system includes a boiler 1, a turbine unit, and a cryogenic economizer 3. The steam outlet of the boiler 1 is connected to the steam inlet of the turbine unit, the steam outlet of the turbine unit is connected to the liquid inlet of the boiler 1, and the flue gas outlet of the boiler 1 is connected to the flue gas inlet of the cryogenic economizer 3. The seawater desalination subsystem includes a multi-stage flash chamber. The seawater outlet of the cryogenic economizer 3 is connected to the seawater inlet of the multi-stage flash chamber, the steam outlet of the multi-stage flash chamber is connected to the return water inlet of the cryogenic economizer 3, the turbine unit is connected to the multi-stage flash chamber, the freshwater outlet of the multi-stage flash chamber is used to output freshwater, and the cryogenic economizer 3 has a seawater inlet for inputting seawater.

[0020] The flue gas waste heat recovery combined with multi-stage distillation seawater desalination system for deep peak shaving in this invention includes a power generation system and a seawater desalination subsystem. The power generation system includes a boiler 1, a turbine unit, and a low-temperature economizer 3. The seawater desalination subsystem includes a multi-stage flash chamber. The flue gas outlet of the boiler 1 is connected to the flue gas inlet of the low-temperature economizer 3, and the seawater outlet of the low-temperature economizer 3 is connected to the seawater inlet of the multi-stage flash chamber. Seawater enters the low-temperature economizer 3 through the seawater inlet and absorbs the heat from the high-temperature flue gas output from the boiler 1 to the low-temperature economizer 3. After absorbing heat, the temperature of the seawater increases, and it flows out from the seawater outlet of the low-temperature economizer 3 and enters the multi-stage flash chamber through the seawater inlet. The seawater undergoes multi-stage pressure reduction and cascade utilization of heat energy in the multi-stage flash chamber, efficiently and stably converting seawater into freshwater. By connecting the steam turbine unit to a multi-stage flash chamber, the higher-temperature steam from the turbine unit is drawn into the flash chamber. This higher-temperature steam exchanges heat with the seawater in the flash chamber, further increasing the seawater temperature and thus improving the desalination efficiency of the multi-stage flash chamber. Furthermore, drawing the higher-temperature steam from the turbine unit into the flash chamber reduces the steam flow rate within the turbine unit, thereby reducing power generation and achieving deep peak shaving.

[0021] This invention relates to a flue gas waste heat recovery combined with multi-stage distillation seawater desalination system for deep peak shaving. By utilizing the waste heat of boiler 1 in stages, the system transfers the heat energy of boiler 1 to the seawater desalination process, thereby reducing energy consumption during desalination. High-temperature steam is extracted from the turbine unit and mixed with low-temperature steam in the seawater desalination subsystem, then directly input into the desalination subsystem, improving the overall efficiency of the seawater desalination subsystem and deepening the peak shaving depth of the power generation system. Under varying power plant load conditions, the system rationally allocates energy, ensuring synergistic optimization of power generation, water production, and resource recovery, thus improving the system's economic efficiency and environmental friendliness. The system provided by this invention has high-efficiency heat recovery capabilities and multi-stage co-production effects, enabling stable operation and ensuring efficient water resource production even under significant power plant load variations.

[0022] In some embodiments of the present invention, the multi-stage flash chamber includes a first flash chamber 15, a second flash chamber 16, a third flash chamber 17, and a fourth flash chamber 18 connected in sequence with progressively decreasing pressure. Specifically, the seawater outlet of the low-temperature economizer 3 is connected to the seawater inlet of the first flash chamber 15, the steam outlet of the first flash chamber 15 is connected to the steam inlet of the second flash chamber 16, the steam outlet of the second flash chamber 16 is connected to the steam inlet of the third flash chamber 17, the steam outlet of the third flash chamber 17 is connected to the steam inlet of the fourth flash chamber 18, and the steam outlet of the fourth flash chamber 18 is connected to the return water inlet of the low-temperature economizer 3.

[0023] When the seawater in the low-temperature economizer 3 is heated, it is output through the seawater outlet of the low-temperature economizer 3 and enters the first flash chamber 15 through the seawater inlet. The seawater undergoes a first desalination process in the first flash chamber 15 to generate first steam and fresh water. The first steam flows sequentially through the steam outlet of the first flash chamber 15 and the steam inlet of the second flash chamber 16 before entering the second flash chamber 16. The seawater undergoes a second desalination process in the second flash chamber 16 to generate second steam and fresh water. The second steam flows sequentially through the second flash chamber 16. The seawater enters the third flash chamber 17 after passing through the steam outlet and the steam inlet of the third flash chamber 17. In the third flash chamber 17, the seawater undergoes a third desalination process to generate third steam and fresh water. The third steam then flows sequentially through the steam outlet of the third flash chamber 17 and the steam inlet of the fourth flash chamber 18 before entering the fourth flash chamber 18. In the fourth flash chamber 18, the seawater undergoes a fourth desalination process to generate fourth steam and fresh water. The fourth steam then flows sequentially through the steam outlet of the fourth flash chamber and the return water inlet of the low-temperature economizer 3 before entering the low-temperature economizer 3. In the low-temperature economizer 3, the fourth steam mixes with the seawater and exchanges heat to raise the seawater temperature, thereby improving the efficiency of the seawater desalination process.

[0024] In some embodiments of the present invention, the seawater desalination subsystem further includes a freshwater storage tank 19, which is connected to the freshwater outlet of each flash chamber in the multi-stage flash chamber system. Specifically, the freshwater outlets of the first flash chamber 15, the second flash chamber 16, the third flash chamber 17, and the fourth flash chamber 18 are respectively connected to the freshwater storage tank 19 to store the freshwater separated from each flash chamber.

[0025] In some embodiments of the present invention, the seawater desalination subsystem further includes a steam ejector 14, which has a first inlet and a second inlet. The first inlet of the steam ejector 14 is connected to a steam turbine unit, the second inlet of the steam ejector 14 is connected to the steam outlet of a second flash chamber 16, and the jet outlet of the steam ejector 14 is connected to the steam inlet of a first flash chamber 15. Specifically, high-temperature and high-pressure steam in the steam turbine unit enters the steam ejector 14 through the first inlet and serves as the working fluid of the steam ejector 14. Steam output from the second flash chamber 16 is input to the second inlet of the steam ejector 14 through its steam outlet and enters the steam ejector 14 as the jet fluid of the steam ejector 14. The steam ejector 14 uses high-temperature, high-pressure steam entering through the first inlet to draw in low-pressure steam entering through the second inlet. The steam from the two inlets mixes in the steam ejector 14. The pressure of the mixed steam is greater than that of the steam at the second inlet. The mixed steam is then ejected through the steam outlet of the steam ejector 14 into the first flash chamber 15. The mixed steam mixes with the seawater in the first flash chamber 15 and transfers heat to the seawater, raising its temperature and providing the heat source required for evaporation.

[0026] In some embodiments of the present invention, the power generation system further includes an air preheater 2. The hot-side inlet of the air preheater 2 is connected to the flue gas outlet of the boiler 1, and the hot-side outlet of the air preheater 2 is connected to the flue gas inlet of the low-temperature economizer 3. The high-temperature flue gas discharged from the boiler 1 enters the air preheater 2 through the hot-side inlet and exchanges heat with the air in the air preheater 2 to transfer heat to the air and achieve the purpose of preheating the air. After releasing heat, the high-temperature flue gas is discharged through the hot-side outlet of the air preheater 2 and enters the low-temperature economizer 3 through the flue gas inlet of the low-temperature economizer 3. The flue gas still has a certain amount of heat. In the low-temperature economizer 3, the flue gas exchanges heat with seawater to release the heat of the flue gas into the seawater, causing the seawater to heat up. After releasing heat, the flue gas is discharged through the flue gas outlet of the low-temperature economizer 3.

[0027] Specifically, the flue gas temperature at the flue gas inlet of the low-temperature economizer 3 is 140℃~180℃, the flue gas temperature at the flue gas outlet of the low-temperature economizer 3 is 85℃~100℃, the temperature range of the flue gas entering the low-temperature economizer 3 through the flue gas inlet is 140℃~180℃, after the flue gas transfers some heat to the seawater, the temperature range of the flue gas discharged through the flue gas outlet is 85℃~100℃.

[0028] Correspondingly, the seawater temperature at the seawater inlet of the low-temperature economizer 3 is 20℃~30℃, and the seawater temperature at the seawater outlet of the low-temperature economizer 3 is 75℃~90℃. The temperature range of the seawater entering the low-temperature economizer 3 through the seawater inlet is 20℃~30℃. After the seawater absorbs heat from the flue gas and heats up, the temperature range of the seawater discharged through the seawater outlet of the low-temperature economizer 3 is 75℃~90℃.

[0029] Figure 2 The data shows that during operation, the outlet temperatures of both flue gas and seawater in the cryogenic economizer 3 significantly increase with increasing load rate. This indicates that the cryogenic economizer 3 exhibits good performance in heat exchange and can effectively transfer heat from the flue gas to the seawater.

[0030] In some embodiments of the present invention, the steam turbine unit includes a high-pressure cylinder 4, an intermediate-pressure cylinder 5, a low-pressure cylinder 6, and a generator 7 connected in sequence. The steam outlet of the boiler 1 is connected to the high-pressure cylinder 4 and the intermediate-pressure cylinder 5, and the intermediate-pressure cylinder 5 is connected to the low-pressure cylinder 6. The steam outlets of the high-pressure cylinder 4, the intermediate-pressure cylinder 5, and the low-pressure cylinder 6 are respectively connected to the liquid inlet of the boiler 1. The steam output from the boiler 1 is input into the high-pressure cylinder 4 and the intermediate-pressure cylinder 5 through the steam outlet, so that the high-pressure cylinder 4 and the intermediate-pressure cylinder 5 perform work. The high-pressure cylinder 4 and the intermediate-pressure cylinder 5 drive the coaxially connected generator 7 to operate, thereby generating electricity. The intermediate-pressure cylinder 5 is connected to the steam inlet of the low-pressure cylinder 6. The steam in the intermediate-pressure cylinder 5 is extracted into the low-pressure cylinder 6, so that the low-pressure cylinder 6 operates, driving the coaxially connected generator 7 to generate electricity. After the steam in the high-pressure cylinder 4, medium-pressure cylinder 5 and low-pressure cylinder 6 does work, it is discharged through its respective steam outlet and eventually returns to the liquid inlet of boiler 1. Boiler 1 processes the steam output from each cylinder into high-temperature steam, thereby realizing the circulation of steam in boiler 1 and steam turbine unit.

[0031] In some embodiments of the present invention, the intermediate-pressure cylinder 5 is connected to the seawater desalination subsystem. Specifically, the intermediate-pressure cylinder 5 is connected to the first inlet of the steam ejector 14 of the seawater desalination subsystem, so that steam with a certain temperature and pressure in the intermediate-pressure cylinder 5 is drawn into the steam ejector 14 through the first inlet to serve as a working fluid with a certain temperature and pressure.

[0032] In some embodiments of the present invention, the power generation system further includes a condenser 8, a first low-pressure heater 9, a second low-pressure heater 10, a deaerator 11, a first high-pressure heater 12, and a second high-pressure heater 13 connected in sequence. The condenser 8 is connected to the first steam outlet of the low-pressure cylinder 6. The inlet of the first low-pressure heater 9 is connected to the second steam outlet of the low-pressure cylinder 6, the inlet of the second low-pressure heater 10 is connected to the first steam outlet of the intermediate-pressure cylinder 5, the inlet of the deaerator 11 is connected to the extraction steam outlet of the intermediate-pressure cylinder 5, the inlet of the first high-pressure heater 12 is connected to the second steam outlet of the intermediate-pressure cylinder 5, the inlet of the second high-pressure heater 13 is connected to the steam outlet of the high-pressure cylinder 4, and the steam outlet of the second high-pressure heater 13 is connected to the liquid inlet of the boiler 1. Specifically, the steam output from the low-pressure cylinder 6 via its first steam outlet flows sequentially through the condenser 8, the first low-pressure heater 9, the second low-pressure heater 10, the deaerator 11, the first high-pressure heater 12, the second high-pressure heater 13, and the liquid inlet of the boiler 1, before returning to the boiler 1; the steam output from the low-pressure cylinder 6 via its second steam outlet flows sequentially through the first low-pressure heater 9, the second low-pressure heater 10, the deaerator 11, the first high-pressure heater 12, the second high-pressure heater 13, and the liquid inlet of the boiler 1, before returning to the boiler 1; the steam output from the intermediate-pressure cylinder 5 via its first steam outlet flows sequentially through the second low-pressure heater 10, the deaerator 11, the first high-pressure heater 12, the second high-pressure heater 13, and the liquid inlet of the boiler 1, before returning to the boiler 1. Steam from the second steam outlet of the intermediate-pressure cylinder 5 flows sequentially through the first high-pressure heater 12, the second high-pressure heater 13, and the inlet of the boiler 1, returning to the boiler 1. Steam from the extraction steam outlet of the intermediate-pressure cylinder 5 flows sequentially through the deaerator 11, the first high-pressure heater 12, the second high-pressure heater 13, and the inlet of the boiler 1, returning to the boiler 1. Steam from the extraction steam outlet of the intermediate-pressure cylinder 5 also directly enters the steam ejector 14 through the first inlet of the steam ejector 14. Steam from the steam outlet of the high-pressure cylinder 4 flows sequentially through the second high-pressure heater 13 and the inlet of the boiler 1, returning to the boiler 1.

[0033] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A flue gas waste heat recovery combined with multi-stage distillation and seawater desalination system for deep peak shaving, characterized in that, Including the electronic power generation system and the seawater desalination subsystem; The power generation system includes: a boiler, a steam turbine unit, and a low-temperature economizer. The steam outlet of the boiler is connected to the steam inlet of the steam turbine unit, the steam outlet of the steam turbine unit is connected to the liquid inlet of the boiler, and the flue gas outlet of the boiler is connected to the flue gas inlet of the low-temperature economizer. The seawater desalination subsystem includes a multi-stage flash chamber. The seawater outlet of the low-temperature economizer is connected to the seawater inlet of the multi-stage flash chamber. The steam outlet of the multi-stage flash chamber is connected to the return water inlet of the low-temperature economizer. The steam turbine unit is connected to the multi-stage flash chamber. The freshwater outlet of the multi-stage flash chamber is used to output freshwater. The low-temperature economizer has a seawater inlet for inputting seawater.

2. The flue gas waste heat recovery combined with multi-stage distillation seawater desalination system for deep peak shaving according to claim 1, characterized in that, The multi-stage flash chamber includes a first flash chamber, a second flash chamber, a third flash chamber, and a fourth flash chamber connected in sequence. The seawater outlet of the low-temperature economizer is connected to the seawater inlet of the first flash chamber, and the steam outlet of the fourth flash chamber is connected to the return water inlet of the low-temperature economizer.

3. The flue gas waste heat recovery combined with multi-stage distillation seawater desalination system for deep peak shaving according to claim 2, characterized in that, The seawater desalination subsystem further includes: a steam ejector, the first inlet of which is connected to the turbine unit, the second inlet of which is connected to the steam outlet of the second flash chamber, and the ejection outlet of which is connected to the steam inlet of the first flash chamber.

4. The flue gas waste heat recovery combined with multi-stage distillation seawater desalination system for deep peak shaving according to claim 1, characterized in that, The seawater desalination subsystem further includes a freshwater storage tank, which is connected to the freshwater outlet of each of the multi-stage flash chambers.

5. The flue gas waste heat recovery combined with multi-stage distillation seawater desalination system for deep peak shaving according to claim 1, characterized in that, The power generation system also includes an air preheater, the hot-side inlet of which is connected to the flue gas outlet of the boiler, and the hot-side outlet of which is connected to the flue gas inlet of the low-temperature economizer.

6. The flue gas waste heat recovery combined with multi-stage distillation and seawater desalination system for deep peak shaving according to claim 1, characterized in that, The steam turbine unit includes a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, and a generator connected in sequence. The steam outlet of the boiler is connected to the high-pressure cylinder and the intermediate-pressure cylinder, and the intermediate-pressure cylinder is connected to the low-pressure cylinder. The steam outlets of the high-pressure cylinder, the intermediate-pressure cylinder, and the low-pressure cylinder are respectively connected to the liquid inlet of the boiler.

7. The flue gas waste heat recovery combined with multi-stage distillation seawater desalination system for deep peak shaving according to claim 6, characterized in that, The medium-pressure cylinder is connected to the seawater desalination subsystem.

8. The flue gas waste heat recovery combined with multi-stage distillation seawater desalination system for deep peak shaving according to claim 6, characterized in that, The power generation system further includes a condenser, a first low-pressure heater, a second low-pressure heater, a deaerator, a first high-pressure heater, and a second high-pressure heater connected in sequence. The condenser is connected to the steam outlet of the low-pressure cylinder, the inlet of the first low-pressure heater is connected to the first steam outlet of the low-pressure cylinder, the inlet of the second low-pressure heater is connected to the first steam outlet of the intermediate-pressure cylinder, the inlet of the deaerator is connected to the extraction steam outlet of the intermediate-pressure cylinder, the inlet of the first high-pressure heater is connected to the second steam outlet of the intermediate-pressure cylinder, the inlet of the second high-pressure heater is connected to the steam outlet of the high-pressure cylinder, and the steam outlet of the second high-pressure heater is connected to the liquid inlet of the boiler.

9. The flue gas waste heat recovery combined with multi-stage distillation seawater desalination system for deep peak shaving according to claim 1, characterized in that, The flue gas temperature at the flue gas inlet of the low-temperature economizer is 140℃~180℃, and the flue gas temperature at the flue gas outlet of the low-temperature economizer is 85℃~100℃.

10. The flue gas waste heat recovery combined with multi-stage distillation seawater desalination system for deep peak shaving according to claim 1, characterized in that, The seawater temperature at the seawater inlet of the low-temperature economizer is 20℃~30℃, and the seawater temperature at the seawater outlet of the low-temperature economizer is 75℃~90℃.

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