Multifunctional energy storage system based on ultrahigh-temperature compressed air

Abstract

The invention relates to the technical field of air energy storage, in particular to a multifunctional energy storage system based on ultrahigh-temperature compressed air, which comprises an air preheating system, an air compression system, an air expansion power generation system, an air storage system, a multi-stage compression heat recycling system and a final-stage compression heat cooling system, the compressed air system is used for pressurizing air, the air expansion power generation system uses high-pressure air to enter a turbine to expand and do work, the air storage system is used for storing the pressurized high-pressure air, and the multi-stage compression heat recycling system is used for recycling and storing compression heat of all stages of air. The final-stage compression heat cooling system is used for cooling high-pressure and high-temperature air; according to the invention, peak load shifting and stable output can be realized, the influence of fluctuation and intermittency of renewable energy on the power quality of the power grid is reduced, the capability of the power grid to deal with faults is enhanced, and the requirements of users on safety, reliability, high efficiency and high quality of electric energy are met.

Description

Technical Field

[0001] The present invention relates to the technical field of air energy storage, and in particular to a multifunctional energy storage system based on ultra-high temperature compressed air. Background Art

[0002] The scale of new energy power generation in my country, mainly wind and solar power, is expanding rapidly. By the end of 2023, the total installed capacity of power generation in China will be about 2.9 billion kW, of which renewable energy will reach 1.45 billion kW, accounting for more than 50%, which has historically exceeded the installed capacity of thermal power. It has become a new force to ensure the power supply in my country, and this proportion is still showing an upward trend. In 2023, the national renewable energy power generation will be about 3 trillion kWh, accounting for about 1 / 3 of the total electricity consumption in the society. In 2024, the new installed capacity of wind power and photovoltaic power in the country is expected to reach 200 million kW.

[0003] Wind and solar power generation has inherent disadvantages such as intermittency and instability, so seeking technologies that can achieve rapid peak regulation and balance grid load has become a hot topic in current research. Compressed air energy storage technology is an effective way to solve the above-mentioned problems of wind power and photovoltaics. Summary of the invention

[0004] The purpose of the present invention is to address the above-mentioned deficiencies and provide a multifunctional energy storage system based on ultra-high temperature compressed air, which can achieve peak shaving and valley filling and smooth output, reduce the impact of the volatility and intermittency of renewable energy on the power quality of the power grid, enhance the power grid's ability to respond to faults, and meet users' requirements for safe, reliable, efficient and high-quality electricity. It is an important technology for building a new power system and an important support for achieving the "dual carbon" goal.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A multifunctional energy storage system based on ultra-high temperature compressed air includes an air preheating system, a compressed air system, an air expansion power generation system, an air storage system, a multi-stage compression heat recovery system and a final compression heat cooling system. The air preheating system is used to preheat the air, the compressed air system is used to pressurize the air, the air expansion power generation system uses high-pressure air to enter the turbine to expand and perform work, the air storage system is used to store the pressurized high-pressure air, the multi-stage compression heat recovery system is used to recover and store the compression heat of each stage of air, and it is reused in the air expansion stage, and the final compression heat cooling system is used to cool the high-pressure and high-temperature air at the outlet of the final compressor.

[0007] Furthermore, the air preheating system includes an air preheater, cold air enters the air preheater from inlet a, and the preheated air enters the compressed air system from inlet b.

[0008] Furthermore, the compressed air system includes a stage I compressor, a centrifugal compressor, a first clutch gearbox, a first motor, a second motor, a second clutch gearbox, a stage II compressor, a third motor, a third clutch gearbox, a stage III compressor, a two-stage first cooler and a second cooler, and a single-stage third cooler; the stage I compressor is an axial-centrifugal compressor arranged in series and coaxially, the centrifugal compressor is connected to the first motor via the first clutch gearbox, the stage II compressor is a fixed-speed centrifugal compressor, connected to the second motor via the second clutch gearbox, the stage III compressor is a variable-speed centrifugal compressor, connected to the third motor via the third clutch gearbox, the first motor is used to drive the stage I compressor and the centrifugal compressor, the second motor is used to drive the stage II compressor, and the third motor is used to drive the stage III compressor; the air preheated by the air preheater enters the stage I compressor from the inlet b, the terminal outlet e of the stage I compressor is connected to the inlet f of the first cooler, the outlet k of the second cooler is connected to the inlet L of the stage II compressor, the outlet m of the stage II compressor is connected to the inlet n of the third cooler, the outlet q of the third cooler is connected to the inlet r of the stage III compressor, and the outlet s of the stage III compressor is connected to the air storage system.

[0009] Further, the air expansion power generation system includes a single-stage first heater, a two-stage second heater and a third heater, a stage I expander, a first 3S clutch, a generator, a second 3S clutch, a stage II expander, a stage III expander, and an exhaust chimney; the gas storage system is a high-pressure gas storage tank;

[0010] A first 3S clutch is connected between interface 1 of the generator and the stage I expander, and a second 3S clutch is connected between interface 2 of the generator and the stage II expander. The air from the high-pressure storage tank enters the first heater through inlet w, and enters the inlet aa of the stage I expander through the outlet z of the second heater and the fifth control valve. The air after entering the stage I expander flows out from the outlet ab, enters the second heater and the third heater through the inlet ac of the second heater, and the heated air enters the inlet ai of the stage II expander through the outlet ah of the third heater, flows out from the outlet aj after entering the stage II expander, and directly flows into the stage III expander from the inlet ak, and enters the stage III expander from the outlet aL to be discharged into the exhaust chimney. A connecting pipe is connected to the pipeline between the outlet and inlet w of the high-pressure storage tank, and the other end of the connecting pipe is connected to the pipeline between the outlet ah and the inlet ai, and a sixth control valve is provided on the connecting pipe.

[0011] Further, the air expansion power generation system includes a single-stage first heater, a two-stage second heater and a third heater, a stage I expander, a first 3S clutch, a generator, a second 3S clutch, a stage II expander, a stage III expander, and an exhaust chimney; the gas storage system is a high-pressure gas storage tank;

[0012] A first 3S clutch is connected between interface 1 of the generator and the stage II expander, and a second 3S clutch is connected between interface 2 of the generator and the stage III expander. The air in the high-pressure storage tank enters the first heater through inlet w, enters the inlet aa of the stage I expander through the first heater outlet z and the fifth control valve, flows out from the outlet ab after entering the stage I expander, enters the second heater and the third heater through the second heater inlet ac, and the heated air enters the inlet ai of the stage II expander through the third heater outlet ah, flows out from the outlet aj after entering the stage II expander, and directly flows into the stage III expander from the inlet ak, and enters the stage III expander from the outlet aL and is discharged into the exhaust chimney. A connecting pipe is connected to the pipeline between the outlet and inlet w of the high-pressure storage tank, and the other end of the connecting pipe is connected to the pipeline between the outlet aj and the inlet ak, and the seventh control valve is provided on the connecting pipe.

[0013] Furthermore, the multi-stage compression heat recovery and utilization system comprises a molten salt hot tank, a molten salt cold tank, a first variable frequency molten salt pump, a second variable frequency molten salt pump, a pressure water hot tank and a pressure water cooling tank; the molten salt in the molten salt hot tank flows out from the outlet an and flows into the inlet ag of the third heater, and flows out from the outlet af, passes through the first variable frequency molten salt pump, flows into the molten salt cold tank from the inlet ao of the molten salt cold tank, flows out from the outlet ap of the molten salt cold tank, flows into the first cooler inlet h after passing through the second variable frequency molten salt pump, flows out from the outlet g, flows into the molten salt hot tank from the inlet am of the molten salt hot tank, and repeats the above cycle; the hot water in the pressure water hot tank flows out from the outlet ar of the pressure water hot tank, and flows out from the outlet ar of the pressure water hot tank. After the first control valve, it is divided into two streams, one stream flows into the first heater inlet y and flows out from the first heater outlet x, and the other stream flows into the second heater inlet ae and flows out from the second heater outlet ad. The two streams flow out from the above two outlets x and outlet ad respectively, and after merging, they flow into the pressure water cooling tank from the inlet as through the first variable frequency water pump and flow out from the pressure water cooling tank outlet at. After passing through the second variable frequency water pump, it is divided into two streams, one stream flows in from the second cooler inlet j, and the other stream flows in from the third cooler inlet p. The two streams flow out from the above two outlets i and outlet o respectively, and after merging, they flow into the pressure water heating tank from the inlet aq, and repeat the above cycle.

[0014] Furthermore, the final stage compression heat cooling system comprises a final stage heat exchanger, a third control valve, a cooling tower, a first check valve, a second check valve, a circulating water pump, a fourth control valve and a second control valve; the hot gas flowing out of the outlet s of the stage III compressor enters the final stage heat exchanger through the inlet t, and enters the high-pressure gas storage tank through the outlet u and inlet v of the final stage heat exchanger; the cold water flowing into the inlet bb of the final stage heat exchanger absorbs the heat of the air flowing into the inlet t of the final stage heat exchanger, and the hot water flows out from the outlet au of the final stage heat exchanger and is divided into two streams, one stream flows to the inlet bc of the air preheater through the second control valve, and the other stream flows into the cooling tower from the inlet av of the cooling tower through the third control valve; the cooled cold water flows out from the outlet ax of the cooling tower, flows out through the first check valve and the outlet bd of the air preheater, and merges with the flowing water through the second check valve, and flows into the inlet bb of the final stage heat exchanger again after passing through the circulating water pump and the fourth control valve, and repeats the next cycle.

[0015] Furthermore, the first motor, the second motor, the third motor and the generator are all connected to a transformer via electric wires, and the transformer is electrically connected to a power grid.

[0016] The beneficial effects of the present invention are:

[0017] In actual applications, this patent realizes the energy storage and release of the air compression system by coupling and controlling the air preheating system, compressed air system, air expansion power generation system, air storage system, multi-stage compression heat recovery and utilization system and final compression heat cooling system, and adjusts the compressor inlet temperature according to seasonal changes, making the operation of the entire system more stable; the motor and generator can operate as a phase regulator under non-power generation conditions to compensate for the reactive power of the power grid; as the total amount of new energy connected to the grid gradually increases, the operating mode of this patent is of great significance to ensuring the safety and stability of the power grid, can generate good economic and social benefits, and has good practical application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of Embodiment 1 of the present invention;

[0019] Figure 2 It is a structural schematic diagram of Embodiment 2 of the present invention;

[0020] Figure numerals: 1. air preheater, 2. section I axial flow compressor, 3. section I centrifugal compressor, 4. first clutch gearbox, 5. first motor, 6. second motor, 7. second clutch gearbox, 8. section II fixed speed centrifugal compressor, 9. third motor, 10. third clutch gearbox, 11. section III variable speed centrifugal compressor, 12. first cooler, 13. second cooler, 14. third cooler, 15. molten salt hot tank, 16. molten salt cold tank, 17. first variable frequency molten salt pump, 18. second variable frequency molten salt pump, 19. pressure water hot tank, 20. pressure water cooling tank, 21. first control valve, 22. first variable frequency water pump, 23. . The second variable frequency water pump, 24. The first heater, 25. The third heater, 26. The second heater, 27. The I-stage expander, 28. The first 3S clutch, 29. The generator, 30. The second 3S clutch, 31. The II-stage expander, 32. The III-stage expander, 33. The exhaust chimney, 34. The transformer, 35. The power grid, 36. The final heat exchanger, 37. The third control valve, 38. The cooling tower, 39. The first check valve, 40. The second check valve, 41. The circulating water pump, 42. The fourth control valve, 43. The second control valve, 44. The high-pressure gas storage tank, 45. The fifth control valve, 46. The sixth control valve, 47. The seventh control valve;

[0021] a~ai are the import and export numbers of each equipment. DETAILED DESCRIPTION

[0022] Embodiment 1:

[0023] like Figure 1 As shown, a multifunctional energy storage system based on ultra-high temperature compressed air includes an air preheating system, a compressed air system, an air expansion power generation system, a gas storage system, a multi-stage compression heat recovery system and a final compression heat cooling system, wherein the air preheating system is used to preheat the air, the compressed air system is used to pressurize the air, the air expansion power generation system uses high-pressure air to enter the turbine to expand and perform work, the gas storage system is used to store the pressurized high-pressure air, the multi-stage compression heat recovery system is used to recover and store the compression heat of each stage of air, and is reused in the air expansion stage, and the final compression heat cooling system is used to cool the high-pressure and high-temperature air at the outlet of the final compressor;

[0024] The air preheating system comprises an air preheater 1, cold air enters the air preheater 1 from inlet a, and the preheated air enters the compressed air system from inlet b;

[0025] The compressed air system comprises a stage I compressor 2, a centrifugal compressor 3, a first clutch gearbox 4, a first motor 5, a second motor 6, a second clutch gearbox 7, a stage II compressor 8, a third motor 9, a third clutch gearbox 10, a stage III compressor 11, a two-stage first cooler 12 and a second cooler 13, and a single-stage third cooler 14; the stage I compressor 2 is an axial-flow-centrifugal compressor arranged in series and coaxially, the centrifugal compressor 3 is connected to the first motor 5 via the first clutch gearbox 4, the stage II compressor 8 is a fixed-speed centrifugal compressor connected to the second motor 6 via the second clutch gearbox 7, the stage III compressor 11 is a variable-speed centrifugal compressor connected to the third clutch gearbox 10. The gearbox 10 is connected to the third motor 9, the first motor 5 is used to drive the I-stage compressor 2 and the centrifugal compressor 3, the second motor 6 is used to drive the II-stage compressor 8, and the third motor 9 is used to drive the III-stage compressor 11; the air preheated by the air preheater 1 enters the I-stage compressor 2 from the inlet b, the terminal outlet e of the I-stage compressor 2 is connected to the inlet f of the first cooler 12, the outlet k of the second cooler 13 is connected to the inlet L of the II-stage compressor 8, the outlet m of the II-stage compressor 8 is connected to the inlet n of the third cooler 14, the outlet q of the third cooler 14 is connected to the inlet r of the III-stage compressor 11, and the outlet s of the III-stage compressor 11 is connected to the air storage system;

[0026] The air expansion power generation system includes a single-stage first heater 24, a two-stage second heater 26 and a third heater 25, a stage I expander 27, a first 3S clutch 28, a generator 29, a second 3S clutch 30, a stage II expander 31, a stage III expander 32, and an exhaust chimney 33; the gas storage system is a high-pressure gas storage tank 44;

[0027] A first 3S clutch 28 is connected between the interface 1 of the generator 29 and the I-stage expander 27, and a second 3S clutch 30 is connected between the interface 2 of the generator 29 and the II-stage expander 31. The air from the high-pressure storage tank 44 enters the first heater 24 through the inlet w, enters the inlet aa of the I-stage expander 27 through the outlet z of the second heater 25 and the fifth control valve 45, and the air after entering the I-stage expander 27 flows out from the outlet ab, enters the second heater and the third heater through the inlet ac of the second heater 26, and the heated air enters the inlet ai of the II-stage expander 31 through the outlet ah of the third heater 25, flows out from the outlet aj after entering the II-stage expander 31, and directly flows into the III-stage expander 32 from the inlet ak, and enters the exhaust chimney 33 from the outlet aL after entering the III-stage expander 32 for discharge. A connecting pipe is connected to the pipeline between the outlet and the inlet w of the high-pressure storage tank 44, and the other end of the connecting pipe is connected to the pipeline between the outlet ah and the inlet ai, and a sixth control valve 46 is provided on the connecting pipe;

[0028] The multi-stage compression heat recovery and utilization system comprises a molten salt hot tank 15, a molten salt cold tank 16, a first variable frequency molten salt pump 17, a second variable frequency molten salt pump 18, a pressure water hot tank 19 and a pressure water cooling tank 20; the molten salt in the molten salt hot tank 15 flows out from the outlet an and then flows into the inlet ag of the third heater 25, and flows out from the outlet af, passes through the first variable frequency molten salt pump 17, flows into the molten salt cold tank 16 from the inlet ao of the molten salt cold tank 16, flows out from the outlet ap of the molten salt cold tank 16, flows into the inlet h of the first cooler 12 after passing through the second variable frequency 18 molten salt pump, flows out from the outlet g, and flows into the molten salt hot tank 15 from the inlet am of the molten salt hot tank 15, and repeats the above cycle; the hot water in the pressure water hot tank 19 flows out from the outlet a of the pressure water hot tank 19 r flows out, and is divided into two streams after passing through the first control valve 21, one stream flows into the inlet y of the first heater 24, and flows out from the outlet x of the first heater 24, and the other stream flows into the inlet ae of the second heater 26, and flows out from the outlet ad of the second heater. The two streams flow out from the above two outlets x and outlet ad respectively, and after merging, they flow into the pressure water cooling tank 20 from the inlet as through the first variable frequency water pump 22, and flow out from the outlet at of the pressure water cooling tank 20. After passing through the second variable frequency water pump 23, it is divided into two streams, one stream flows into the inlet j of the second cooler 13, and the other stream flows into the inlet p of the third cooler 14. The two streams flow out from the above two outlets i and outlet o respectively, and after merging, they flow into the pressure water heating tank 19 from the inlet aq, and the above cycle is repeated;

[0029] The final stage compression heat cooling system includes a final stage heat exchanger 36, a third control valve 37, a cooling tower 38, a first check valve 39, a second check valve 40, a circulating water pump 41, a fourth control valve 42 and a second control valve 43; the hot gas flowing out of the outlet s of the stage III compressor 11 enters the final stage heat exchanger 36 through the inlet t, and enters the high-pressure gas storage tank 44 through the outlet u and inlet v of the final stage heat exchanger 36. After the cold water flowing into the inlet bb of the final stage heat exchanger 36 absorbs the heat of the air flowing into the inlet t of the final stage heat exchanger 36, The hot water flows out from the outlet au of the last stage heat exchanger 36 and is divided into two streams. One stream flows to the inlet bc of the air preheater 1 through the second control valve 43, and the other stream flows into the cooling tower 38 through the inlet av of the cooling tower 38 through the third control valve 37. The cooled cold water flows out from the outlet ax of the cooling tower 38, flows out through the first check valve 39 and merges with the water flowing out of the outlet bd of the air preheater 1 and through the second check valve 40, and flows into the inlet bb of the last stage heat exchanger 36 again after passing through the circulating water pump 41 and the fourth control valve 42, and repeats the next cycle.

[0030] The first motor 5, the second motor 6, the third motor 9 and the generator 29 are all connected to a transformer 34 through electric wires, and the transformer 34 is electrically connected to a power grid 35;

[0031] In this embodiment, the first motor 5 drives the stage I compressor 2 and the centrifugal compressor 3, the second motor 6 drives the stage II compressor 8, and the third motor 9 drives the stage III compressor 11, and the first motor 5, the second motor 6 and the third motor 9 are all connected to the power grid. When the system is in a non-compression state, the clutch gearbox is disconnected and can be operated to generate reactive power;

[0032] In the non-working state, the first 3S clutch 28 and the second 3S clutch 30 at both ends of the generator 29 are disconnected and intercepted. Since the generator 29 is directly connected to the power grid 35, it can perform reactive power operation;

[0033] When the power system fails, the system high-pressure cylinder is cut off through the first clutch 28. At this time, the fifth control valve 45 is disconnected, the sixth control valve 46 is turned on, and air directly enters the system high-pressure cylinder from the high-pressure storage tank 44 to perform work, further improving the black start efficiency.

[0034] The outlet temperature of the first-stage centrifugal compressor 3 in high-temperature operation is about 520°C, and the high-grade compression heat is recovered by two-stage heat exchange of molten salt and pressurized water; the second-stage compression adopts a fixed-speed centrifugal compressor 8, whose outlet temperature is about 210°C, and the low-grade compression heat is recovered by single-stage pressurized water;

[0035] The turbo expander is a single-shaft, one-stage reheating air-supply type, with a main gas temperature of 190°C, a reheat gas temperature of 500°C, and a total efficiency of 93.3%.

[0036] In this embodiment, the application is applicable to 19MPa high-pressure air operation in high-cold and arid conditions with a temperature of about -20°C and a wide temperature range of -20°C to 30°C;

[0037] In this embodiment, the output air pressure of the high-pressure storage tank 44 gradually decreases as the system continues to generate electricity. When the output drops to a suitable load (about 80% of the total system load), the first 3S clutch 28 can be used to cut off the I-stage expander 27, and the compressed air directly enters the II-stage expander 31 and the III-stage expander 32 to perform work. At this time, the air pressure inlet matches the expander, which can further improve the system efficiency.

[0038] Since the first cooler 12 and the second heater 13 are molten salt-air hairpin heat exchangers, the heat exchange end difference is 15°C, and the air side pressure loss is ≯50kPa; the second cooler 13, the third cooler 14, the first heater 24, and the third heater 25 are water-air cross-flow heat exchangers, the heat exchange end difference is 10°C, and the air side pressure loss is ≯30kPa.

[0039] Embodiment 2:

[0040] like Figure 2As shown, a multifunctional energy storage system based on ultra-high temperature compressed air includes an air preheating system, a compressed air system, an air expansion power generation system, a gas storage system, a multi-stage compression heat recovery system and a final compression heat cooling system, wherein the air preheating system is used to preheat the air, the compressed air system is used to pressurize the air, the air expansion power generation system uses high-pressure air to enter the turbine to expand and perform work, the gas storage system is used to store the pressurized high-pressure air, the multi-stage compression heat recovery system is used to recover and store the compression heat of each stage of air, and is reused in the air expansion stage, and the final compression heat cooling system is used to cool the high-pressure and high-temperature air at the outlet of the final compressor;

[0041] The air preheating system comprises an air preheater 1, cold air enters the air preheater 1 from inlet a, and the preheated air enters the compressed air system from inlet b;

[0042] The compressed air system comprises a stage I compressor 2, a centrifugal compressor 3, a first clutch gearbox 4, a first motor 5, a second motor 6, a second clutch gearbox 7, a stage II compressor 8, a third motor 9, a third clutch gearbox 10, a stage III compressor 11, a two-stage first cooler 12 and a second cooler 13, and a single-stage third cooler 14; the stage I compressor 2 is an axial-flow-centrifugal compressor arranged in series and coaxially, the centrifugal compressor 3 is connected to the first motor 5 via the first clutch gearbox 4, the stage II compressor 8 is a fixed-speed centrifugal compressor connected to the second motor 6 via the second clutch gearbox 7, the stage III compressor 11 is a variable-speed centrifugal compressor connected to the third clutch gearbox 10. The gearbox 10 is connected to the third motor 9, the first motor 5 is used to drive the I-stage compressor 2 and the centrifugal compressor 3, the second motor 6 is used to drive the II-stage compressor 8, and the third motor 9 is used to drive the III-stage compressor 11; the air preheated by the air preheater 1 enters the I-stage compressor 2 from the inlet b, the terminal outlet e of the I-stage compressor 2 is connected to the inlet f of the first cooler 12, the outlet k of the second cooler 13 is connected to the inlet L of the II-stage compressor 8, the outlet m of the II-stage compressor 8 is connected to the inlet n of the third cooler 14, the outlet q of the third cooler 14 is connected to the inlet r of the III-stage compressor 11, and the outlet s of the III-stage compressor 11 is connected to the air storage system;

[0043] The air expansion power generation system includes a single-stage first heater 24, a two-stage second heater 26 and a third heater 25, a stage I expander 27, a first 3S clutch 28, a generator 29, a second 3S clutch 30, a stage II expander 31, a stage III expander 32, and an exhaust chimney 33; the gas storage system is a high-pressure gas storage tank 44;

[0044] A first 3S clutch 28 is connected between the interface 1 of the generator 29 and the II-stage expander 31, and a second 3S clutch 30 is connected between the interface 2 of the generator 29 and the III-stage expander 32. The air in the high-pressure storage tank 44 enters the first heater 24 through the inlet w, enters the inlet aa of the I-stage expander 27 through the outlet z of the first heater 24 and the fifth control valve 45, flows out from the outlet ab after entering the I-stage expander 27, enters the second heater 26 and the third heater 25 through the inlet ac of the second heater 26, and the heated air enters the inlet ai of the II-stage expander 31 through the outlet ah of the third heater 25, flows out from the outlet aj after entering the II-stage expander 31, and directly flows into the III-stage expander 32 from the inlet ak, and enters the III-stage expander 32 from the outlet aL to be discharged. A connecting pipe is connected to the pipeline between the outlet and the inlet w of the high-pressure storage tank 44, and the other end of the connecting pipe is connected to the pipeline between the outlet aj and the inlet ak, and a seventh control valve 47 is provided on the connecting pipe;

[0045] The multi-stage compression heat recovery and utilization system comprises a molten salt hot tank 15, a molten salt cold tank 16, a first variable frequency molten salt pump 17, a second variable frequency molten salt pump 18, a pressure water hot tank 19 and a pressure water cooling tank 20; the molten salt in the molten salt hot tank 15 flows out from the outlet an and then flows into the inlet ag of the third heater 25, and flows out from the outlet af, passes through the first variable frequency molten salt pump 17, flows into the molten salt cold tank 16 from the inlet ao of the molten salt cold tank 16, flows out from the outlet ap of the molten salt cold tank 16, flows into the inlet h of the first cooler 12 after passing through the second variable frequency 18 molten salt pump, flows out from the outlet g, and flows into the molten salt hot tank 15 from the inlet am of the molten salt hot tank 15, and repeats the above cycle; the hot water in the pressure water hot tank 19 flows out from the outlet a of the pressure water hot tank 19 r flows out, and is divided into two streams after passing through the first control valve 21, one stream flows into the inlet y of the first heater 24, and flows out from the outlet x of the first heater 24, and the other stream flows into the inlet ae of the second heater 26, and flows out from the outlet ad of the second heater. The two streams flow out from the above two outlets x and outlet ad respectively, and after merging, they flow into the pressure water cooling tank 20 from the inlet as through the first variable frequency water pump 22, and flow out from the outlet at of the pressure water cooling tank 20. After passing through the second variable frequency water pump 23, it is divided into two streams, one stream flows into the inlet j of the second cooler 13, and the other stream flows into the inlet p of the third cooler 14. The two streams flow out from the above two outlets i and outlet o respectively, and after merging, they flow into the pressure water heating tank 19 from the inlet aq, and the above cycle is repeated;

[0046] The final stage compression heat cooling system includes a final stage heat exchanger 36, a third control valve 37, a cooling tower 38, a first check valve 39, a second check valve 40, a circulating water pump 41, a fourth control valve 42 and a second control valve 43; the hot gas flowing out of the outlet s of the stage III compressor 11 enters the final stage heat exchanger 36 through the inlet t, and enters the high-pressure gas storage tank 44 through the outlet u and inlet v of the final stage heat exchanger 36. After the cold water flowing into the inlet bb of the final stage heat exchanger 36 absorbs the heat of the air flowing into the inlet t of the final stage heat exchanger 36, The hot water flows out from the outlet au of the last stage heat exchanger 36 and is divided into two streams. One stream flows to the inlet bc of the air preheater 1 through the second control valve 43, and the other stream flows into the cooling tower 38 through the inlet av of the cooling tower 38 through the third control valve 37. The cooled cold water flows out from the outlet ax of the cooling tower 38, flows out through the first check valve 39 and merges with the water flowing out of the outlet bd of the air preheater 1 and through the second check valve 40, and flows into the inlet bb of the last stage heat exchanger 36 again after passing through the circulating water pump 41 and the fourth control valve 42, and repeats the next cycle.

[0047] The first motor 5, the second motor 6, the third motor 9 and the generator 29 are all connected to a transformer 34 through electric wires, and the transformer 34 is electrically connected to a power grid 35;

[0048] In this embodiment, if the I-stage expander 27 accounts for a small proportion of the entire unit load and the power distribution on both sides of the clutch is uneven, the generator 29 and the 3S clutches 28 and 30 are arranged between the II-stage expander 31 and the III-stage expander 32;

[0049] In the non-working state, the first 3S clutch 28 and the second 3S clutch 30 at both ends of the generator 29 are disconnected and intercepted. Since the generator 29 is directly connected to the power grid 35, it can perform reactive power operation;

[0050] When the power system fails, the first 3S clutch 28 can be used to cut off the connection between the generator 29 and the stage I expander 27 and the stage II expander 31, and the second 3S clutch 30 can cut off the connection between the generator 29 and the stage III expander 32. At this time, the fifth control valve 45 is cut off and the seventh control valve 47 is turned on. The high-pressure air from the outlet of the high-pressure storage tank 44 can directly enter the stage III expander 32 through the seventh control valve 47 to perform work.

[0051] The specific embodiments described herein are merely examples of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways without departing from the scope of the present invention.

Claims

1. A multifunctional energy storage system based on ultra-high temperature compressed air, characterized in that: It includes an air preheating system, a compressed air system, an air expansion power generation system, an air storage system, a multi-stage compression heat recovery system and a final compression heat cooling system. The air preheating system is used to preheat the air, the compressed air system is used to pressurize the air, the air expansion power generation system uses high-pressure air to enter the turbine to expand and do work, the air storage system is used to store the pressurized high-pressure air, the multi-stage compression heat recovery system is used to recover and store the compression heat of each stage of air, and it is reused in the air expansion stage, and the final compression heat cooling system is used to cool the high-pressure and high-temperature air at the outlet of the final compressor.

2. A multifunctional energy storage system based on ultra-high temperature compressed air according to claim 1, characterized in that: The air preheating system comprises an air preheater, cold air enters the air preheater from inlet a, and the preheated air enters the compressed air system from inlet b.

3. A multifunctional energy storage system based on ultra-high temperature compressed air according to claim 2, characterized in that: The compressed air system includes a stage I compressor, a centrifugal compressor, a first clutch gearbox, a first motor, a second motor, a second clutch gearbox, a stage II compressor, a third motor, a third clutch gearbox, a stage III compressor, a two-stage first cooler and a second cooler, and a single-stage third cooler; The stage I compressor is an axial-flow centrifugal compressor coaxially arranged in series, the centrifugal compressor is connected to the first motor via the first clutch gearbox, the stage II compressor is a fixed-speed centrifugal compressor, connected to the second motor via the second clutch gearbox, the stage III compressor is a variable-speed centrifugal compressor, connected to the third motor via the third clutch gearbox, the first motor is used to drive the stage I compressor and the centrifugal compressor, the second motor is used to drive the stage II compressor, and the third motor is used to drive the stage III compressor; The air preheated by the air preheater enters the stage I compressor from the inlet b, the terminal outlet e of the stage I compressor is connected to the inlet f of the first cooler, the outlet k of the second cooler is connected to the inlet L of the stage II compressor, the outlet m of the stage II compressor is connected to the inlet n of the third cooler, the outlet q of the third cooler is connected to the inlet r of the stage III compressor, and the outlet s of the stage III compressor is connected to the air storage system.

4. A multifunctional energy storage system based on ultra-high temperature compressed air according to claim 3, characterized in that: The air expansion power generation system includes a single-stage first heater, a two-stage second heater and a third heater, a stage I expander, a first 3S clutch, a generator, a second 3S clutch, a stage II expander, a stage III expander, and an exhaust chimney; the gas storage system is a high-pressure gas storage tank; A first 3S clutch is connected between interface 1 of the generator and the stage I expander, and a second 3S clutch is connected between interface 2 of the generator and the stage II expander. The air from the high-pressure storage tank enters the first heater through inlet w, and enters the inlet aa of the stage I expander through the outlet z of the second heater and the fifth control valve. The air after entering the stage I expander flows out from the outlet ab, enters the second heater and the third heater through the inlet ac of the second heater, and the heated air enters the inlet ai of the stage II expander through the outlet ah of the third heater, flows out from the outlet aj after entering the stage II expander, and directly flows into the stage III expander from the inlet ak, and enters the stage III expander from the outlet aL to be discharged into the exhaust chimney. A connecting pipe is connected to the pipeline between the outlet and inlet w of the high-pressure storage tank, and the other end of the connecting pipe is connected to the pipeline between the outlet ah and the inlet ai, and a sixth control valve is provided on the connecting pipe.

5. A multifunctional energy storage system based on ultra-high temperature compressed air according to claim 3, characterized in that: The air expansion power generation system comprises a single-stage first heater, a two-stage second heater and a third heater, a stage I expander, a 3S clutch 1, a generator, a 3S clutch 2, a stage II expander, a stage III expander, and an exhaust chimney; the gas storage system is a high-pressure gas storage tank; A first 3S clutch is connected between interface 1 of the generator and the stage II expander, and a second 3S clutch is connected between interface 2 of the generator and the stage III expander. The air in the high-pressure storage tank enters the first heater through inlet w, enters the inlet aa of the stage I expander through the first heater outlet z and the fifth control valve, flows out from the outlet ab after entering the stage I expander, enters the second heater and the third heater through the second heater inlet ac, and the heated air enters the inlet ai of the stage II expander through the third heater outlet ah, flows out from the outlet aj after entering the stage II expander, and directly flows into the stage III expander from the inlet ak, and enters the stage III expander from the outlet aL and is discharged into the exhaust chimney. A connecting pipe is connected to the pipeline between the outlet and inlet w of the high-pressure storage tank, and the other end of the connecting pipe is connected to the pipeline between the outlet aj and the inlet ak, and the seventh control valve is provided on the connecting pipe.

6. A multifunctional energy storage system based on ultra-high temperature compressed air according to claim 4 or 5, characterized in that: The multi-stage compression heat recovery system comprises a molten salt hot tank, a molten salt cold tank, a first variable frequency molten salt pump, a second variable frequency molten salt pump, a pressure water hot tank and a pressure water cold tank; The molten salt in the molten salt hot tank flows out from the outlet an and flows into the inlet ag of the third heater, and flows out from the outlet af, passes through the first variable frequency molten salt pump, flows into the molten salt cold tank from the inlet ao of the molten salt cold tank, flows out from the outlet ap of the molten salt cold tank, flows into the first cooler inlet h after passing through the second variable frequency molten salt pump, flows out from the outlet g, flows into the molten salt hot tank from the inlet am of the molten salt hot tank, and repeats the above cycle; The hot water in the pressure water heating tank flows out from the pressure water heating tank outlet ar, and is divided into two streams after passing through the first control valve, one stream flows into the first heater inlet y and flows out from the first heater outlet x, and the other stream flows into the second heater inlet ae and flows out from the second heater outlet ad. The two water streams flow out from the above two outlets x and outlet ad respectively, and after merging, flow into the pressure water cooling tank from the inlet as through the first variable frequency water pump, and flow out from the pressure water cooling tank outlet at. After passing through the second variable frequency water pump, it is divided into two streams, one stream flows in from the second cooler inlet j, and the other stream flows in from the third cooler inlet p. The two water streams flow out from the above two outlets i and outlet o respectively, and after merging, flow into the pressure water heating tank from the inlet aq, and repeat the above cycle.

7. A multifunctional energy storage system based on ultra-high temperature compressed air according to claim 6, characterized in that: The final stage compression heat cooling system comprises a final stage heat exchanger, a third control valve, a cooling tower, a first check valve, a second check valve, a circulating water pump, a fourth control valve and a second control valve; The hot gas flowing out of the outlet s of the compressor of stage III enters the last stage heat exchanger through the inlet t, and enters the high-pressure gas storage tank through the outlet u and inlet v of the last stage heat exchanger. The cold water flowing into the inlet bb of the last stage heat exchanger absorbs the heat of the air flowing in from the inlet t of the last stage heat exchanger, and then the hot water flows out from the outlet au of the last stage heat exchanger and is divided into two streams, one of which flows to the inlet bc of the air preheater through the second control valve, and the other flows into the cooling tower from the inlet av of the cooling tower through the third control valve. The cooled cold water flows out from the outlet ax of the cooling tower, flows out through the first check valve and the outlet bd of the air preheater, and merges with the flowing water through the second check valve, and flows into the inlet bb of the last stage heat exchanger again after passing through the circulating water pump and the fourth control valve, and repeats the next cycle.

8. A multifunctional energy storage system based on ultra-high temperature compressed air according to claim 7, characterized in that: The first motor, the second motor, the third motor and the generator are all connected to a transformer through electric wires, and the transformer is electrically connected to a power grid.

Images