A supercharged compressed air energy storage system

Abstract

The present invention provides a boosted compressed air energy storage system, comprising a compressor unit, an air storage device, a renewable energy heat exchange unit, an expansion unit, and a compression heat recovery device connected in sequence, wherein the compressor unit comprises a plurality of compressors; the expansion unit comprises a plurality of expanders; the expansion unit is connected to a booster compressor for increasing the total expansion ratio, and the booster compressor is arranged in front of different expanders for selectively absorbing renewable energy heat between the various stages of the expansion unit; the renewable energy heat exchange unit comprises a plurality of renewable energy heat exchangers. The boosted compressed air energy storage system provided by the present invention utilizes compression heat and renewable energy heat to heat the expander inlet air. When the expander inlet temperature is increased, the expansion ratio of the multi-stage expander is increased by using a booster compressor to increase the pressure during energy release, while the expander outlet temperature remains close to room temperature. Thus, on the basis of promoting the absorption of renewable energy, the thermal energy is fully utilized, thereby improving the system efficiency.

Description

Technical Field

[0001] The present invention belongs to the field of energy storage, and in particular relates to a pressurized compressed air energy storage system. Background Art

[0002] Sustainable development of energy and environmental issues is fundamental to national economic development, and resolving energy and environmental challenges in the power industry is a crucial component of ensuring sustainable economic development. Renewable energy, due to its low-carbon nature, has garnered widespread attention and rapid development in recent years. To achieve carbon neutrality, the proportion of renewable energy connected to the grid needs to be further increased. Furthermore, power storage is a key technology for adjusting the energy mix, promoting the large-scale development of renewable energy, and improving energy security. Research on large-scale energy storage technology holds significant theoretical and practical value.

[0003] Current energy storage systems include pumped hydro, compressed air, fuel cells, and flywheels. Pumped hydro and compressed air storage boast high energy density and output power, and are considered suitable for large-scale use. Power stations utilizing pumped hydro require the construction of dams, consume significant amounts of water, and cause significant ecological damage. Compressed air storage, on the other hand, consumes no water and has minimal impact on the ecological environment. It offers advantages such as low initial investment costs, high efficiency, non-toxicity, and a long lifespan, and holds great promise for development. However, current compressed air storage systems suffer from relatively low expansion rates in the expander due to factors such as throttling, resulting in high exhaust temperatures and insufficient utilization of the heat of compression. Consequently, the cycle efficiency of the energy storage system falls far below its theoretical efficiency, resulting in energy waste.

[0004] Currently, the main coupling methods for renewable energy in compressed air energy storage systems are wind power driving the compressor and solar energy heating the expander inlet air. However, renewable energy sources (such as wind power, solar energy, etc.) themselves generally have strong intermittent and fluctuating problems, which will lead to the limited absorption capacity of the compressed air energy storage system (solar energy heating the expander inlet air temperature without making other changes will increase the expander exhaust temperature, resulting in energy waste, and thus the solar energy heating temperature is limited).

[0005] To address these issues, existing technologies have proposed variable operating condition adjustment methods, such as compressor guide vane / diffuser adjustment, expander stator adjustment, and valve throttling / pressure adjustment. However, these methods have a limited range of variable operating conditions, while valve throttling / pressure adjustment results in significant energy losses.

[0006] Therefore, it is necessary to provide a compressed air energy storage system that can achieve efficient and wide-operating-condition operation of the system. Summary of the Invention

[0007] In order to solve the above problems, the purpose of the present invention is to provide a boosted compressed air energy storage system, which is suitable for a variety of compressed air energy storage systems, including thermal storage compressed air energy storage systems, underwater compressed air energy storage systems and supercritical compressed air energy storage systems.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A supercharged compressed air energy storage system, comprising a compressor unit, an air storage device, a renewable energy heat exchange unit, an expansion unit, and a compression heat recovery device connected in sequence.

[0010] The compressor unit includes a plurality of compressors;

[0011] The expander group includes a plurality of expanders;

[0012] The expansion unit is connected to a booster compressor to increase the total expansion ratio.

[0013] The booster compressor is arranged before different expanders and is used to selectively absorb the heat of renewable energy between the stages of the expander group;

[0014] The renewable energy heat exchange unit includes a plurality of renewable energy heat exchangers.

[0015] The booster compressor inlet and outlet can be connected to the expander at different locations using a multi-way valve, allowing them to be adjusted based on load and renewable energy heat. Changing the inlet and outlet positions of the booster compressor selectively absorbs renewable energy heat between compressor stages, achieving highly efficient variable operating conditions.

[0016] The boosted compressed air energy storage system provided by the present invention also has such a feature that the compressor includes one or more compressors selected from a piston compressor, a centrifugal compressor, an axial flow compressor, a screw compressor and a rotor compressor;

[0017] The renewable energy heat exchanger includes one or more heat exchangers selected from shell and tube heat exchangers, plate-fin heat exchangers, plate heat exchangers, spiral tube heat exchangers, double-tube heat exchangers, plate-shell heat exchangers, tube-fin heat exchangers and heat pipe heat exchangers.

[0018] The boosted compressed air energy storage system provided by the present invention also has the characteristic that the expander includes one selected from a piston expander, an axial flow expander, a centrifugal expander, a screw expander or a hybrid expander.

[0019] The boosted compressed air energy storage system provided by the present invention also has the characteristic that the driving energy of the compressor includes one or a combination of two energy sources selected from grid electricity and renewable energy electricity.

[0020] The boosted compressed air energy storage system provided by the present invention also has the characteristic that the booster compressor includes one selected from a piston compressor, an axial flow compressor, a centrifugal compressor, a screw compressor or a hybrid compressor.

[0021] The boosted compressed air energy storage system provided by the present invention also has the characteristic that the booster compressor adopts an isothermal compression mode.

[0022] The boosted compressed air energy storage system provided by the present invention also has the characteristic that the booster compressor is driven by a motor or an expander.

[0023] The boosted compressed air energy storage system provided by the present invention also has the following characteristics: the compressor includes one or more stages of compressors; and the expander includes one or more stages of expanders.

[0024] The boosted compressed air energy storage system provided by the present invention also has the following characteristics: the system also includes a compression heat storage device, and the heat storage material in the compression heat storage device includes one or more selected from water, thermal oil and phase change material.

[0025] The boosted compressed air energy storage system provided by the present invention also has the following characteristics: the system includes a renewable energy heat accumulator disposed between the renewable energy heat source reheat unit and the expansion unit, for smoothing heat fluctuations generated by the renewable energy heat source reheat unit;

[0026] The heat storage material in the renewable energy heat accumulator includes one or two heat storage materials selected from thermal oil and molten salt.

[0027] The boosted compressed air energy storage system provided by the present invention also has the following characteristics: the compressed air energy storage system includes a compressed air energy storage system with a multi-stage compression / expansion unit with indirect cooling / reheating, and the compressed air energy storage system with a multi-stage compression / expansion unit with indirect cooling / reheating includes a thermal storage type compressed air energy storage system, an underwater compressed air energy storage system and a supercritical compressed air energy storage system.

[0028] Beneficial effects:

[0029] The boosted compressed air energy storage system provided by the present invention utilizes compression heat and renewable energy heat to heat the expander inlet air. When the expander inlet temperature increases, the expansion ratio of the multi-stage expander is improved by using a booster compressor to increase pressure during energy release. The expander outlet temperature remains close to room temperature, thereby fully utilizing thermal energy and improving system efficiency while promoting the absorption of renewable energy.

[0030] The booster compressor in the boosted compressed air energy storage system provided by this invention can be driven by one of the multi-stage expanders to form a turbocharger, reducing motor usage and energy loss. Furthermore, the inlet and outlet positions of the booster can be adjusted using multi-way valves and pipeline flow, correspondingly varying the amount of renewable energy heat absorbed, achieving efficient, wide-range operation.

[0031] The system is suitable for a variety of compressed air energy storage systems, including thermal storage compressed air energy storage systems, underwater compressed air energy storage systems and supercritical compressed air energy storage systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 Schematic diagram of the first-stage pressurized supercharged thermal storage compressed air energy storage system provided in Example 1;

[0034] Figure 2 Schematic diagram of the supercharged thermal storage compressed air energy storage system with second-stage supercharging provided in Example 2;

[0035] Figure 3 Schematic diagram of the supercharged supercritical compressed air energy storage system with first-stage supercharging provided in Example 3;

[0036] 1. Air; 2. Multi-stage compressor outlet air; 3. Cooled high-pressure air; 4. High-pressure air before the main valve; 5. High-pressure air after the main valve; 6. Recompressed high-pressure air; 7. Renewable energy heat of the air before the first-stage expander; 8. Renewable energy heat of the air before the second-stage expander; 9. Renewable energy heat of the air before the third-stage expander; 10. Renewable energy heat of the air before the fourth-stage expander; 11. Normal temperature circulating water pump; 12. High temperature circulating water pump; 13. Exhaust; 14. First-stage expander outlet air; 15. Booster compressor inlet air; 16. Air before the liquid expander; 17. Air after the liquid expander; 18. Liquid air; 19. Air after the cryogenic pump; 20. Normal pressure gaseous air; 21: Cold storage / heat exchanger exhaust; C1. First compressor; C2. Second compressor ; C3. Third compressor; C4. Fourth compressor; T1. First-stage expander; T2. Second-stage expander; T3. Third-stage expander; T4. Fourth-stage expander; A1. First intercooler; A2. Second intercooler; A3. Third intercooler; A4. Fourth intercooler; R1. First compression heat reheater; R2. Second compression heat reheater; R3. Third compression heat reheater; R4. Fourth compression heat reheater; B1. First renewable energy heat exchanger; B2. Second renewable energy heat exchanger; B3. Third renewable energy heat exchanger; B4. Fourth renewable energy heat exchanger; AC: aftercooler; V: main valve; TA: air storage tank; TC: booster compressor; Z: axis; CS: normal temperature storage tank; TS: heat storage tank; D: cooler; CE: cold storage / heat exchanger; P: cryogenic pump; L: liquid expander; CY: liquid air storage tank. DETAILED DESCRIPTION

[0037] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the following embodiments and accompanying drawings specifically illustrate the pressurized compressed air energy storage system provided by the present invention.

[0038] In the description of the embodiments of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the invention.

[0039] Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified with "first," "second," etc., may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0040] The terms "mounted," "connected," and "connected" should be understood broadly. For example, they can refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0041] Example 1

[0042] like Figure 1As shown, a first-stage pressurized supercharged thermal storage compressed air energy storage system is provided. The system includes a compressor unit, an air storage device, a renewable energy heat exchange unit, an expansion unit and a compression heat recovery device connected in sequence. The compressor unit includes a first compressor C1, a second compressor C2, a third compressor C3 and a fourth compressor C4; the air storage device is an air storage tank TA, and the compressors C1-C4 are correspondingly provided with intercoolers A1-A4. The compression heat is recovered in the intercoolers A1-A4 and stored in a compression heat storage device, which is a heat storage tank TS. The heat storage medium is pressurized water in this case; the renewable energy heat source reheat unit includes a first renewable energy heat exchanger B1, a second renewable energy heat exchanger B2, a third renewable energy heat exchanger B3 and a fourth renewable energy heat exchanger B4 respectively connected to the renewable energy; the expansion unit includes a first-stage expander T1, a second-stage expander T2, a third-stage expander T3 and a fourth-stage expander T4 corresponding to the renewable energy heat exchangers B1-B4; a booster compressor TC is provided between the air storage tank TA and the first-stage expander T1. This embodiment also features a heat-of-compression reheat unit for heating the air before expansion machines T1-T4. This unit comprises a first heat-of-compression reheater R1, a second heat-of-compression reheater R2, a third heat-of-compression reheater R3, and a fourth heat-of-compression reheater R4. The unit is connected to a thermal storage tank TS and uses the heat of compression stored in the tank to heat the high-pressure air 6 boosted by the booster compressor. The heat storage medium in the tank is cooled and then stored in a normal-temperature storage tank CS. The normal-temperature storage tank CS is connected to an intercooler, through which the heat storage medium receives heat of compression recovered by intercoolers A1-A4. An aftercooler AC is located between the air storage tank TA and the fourth compressor C4. A main valve V is located between the air storage tank TA and the booster compressor TC. A normal-temperature circulating water pump 11 is located at the outlet of the normal-temperature storage tank CS, while a high-temperature circulating water pump 12 is located at the outlet of the thermal storage tank TS. A support shaft Z is located between the booster compressor and the first-stage expansion machine.

[0043] In the compressed air energy storage system provided in the above-mentioned embodiment, the booster compressor increases the pressure of the expander unit, thereby increasing the overall expansion ratio and maximizing the expander's heat absorption capacity after the pressure increase, thereby promoting the full utilization of compression heat and renewable energy heat. The booster-type thermal storage compressed air energy storage system provided in the above-mentioned embodiment can achieve efficient variable-mode operation by varying the booster compressor's pressure ratio and, accordingly, the amount of renewable energy heat absorbed, while maintaining the outlet temperature of each expander at near-ambient temperatures.

[0044] Workflow:

[0045] During the energy storage process, air 1 is compressed to a high pressure state by the multi-stage compressors C1-C4. The outlet air 2 of the multi-stage compressor is cooled by AC to form cooled high-pressure air 3 which is stored in the air storage tank TA. During this period, the compression heat is recovered in the intercoolers A1-A4 and stored in the heat storage tank TS. The heat storage medium is pressurized water.

[0046] During the energy release process, the high-pressure air in the air storage tank TA is released. The released high-pressure air 4 before the main valve passes through the main valve V to obtain high-pressure air 5 after the main valve. The high-pressure air 5 after the main valve enters the booster compressor TC. TC is a near-isothermal compressor whose power source is the work output of the first-stage expander T1. The high-pressure air 6 compressed by the booster compressor TC enters the multi-stage expanders T1-T4 to expand and perform work, and is exhausted 13 at the end of the fourth-stage expander T4 at the end. The air before each expander stage is reheated twice. The first reheating heat source is the heat of compression from the heat storage tank TS. The air reheating process is carried out in the compression heat reheaters R1-R4. The high-temperature water in the heat storage tank TS is discharged by a high-temperature circulating water pump, passes through the compression heat reheaters R1-R4 in sequence, and is then input into the normal-temperature water tank CS. The normal-temperature water in the normal-temperature water tank CS is discharged by a normal-temperature circulating water pump 11, flows through the intercoolers A1-A4 in sequence, absorbs the compression heat recovered by A1-A4, and forms high-temperature water, which is stored in the heat storage tank TS. The second reheating heat source is renewable energy heat 7-10, where 7 is the renewable energy heat input into the air before the first-stage expander, 8 is the renewable energy heat input into the air before the second-stage expander, 9 is the renewable energy heat input into the air before the third-stage expander, and 10 is the renewable energy heat input into the air before the fourth-stage expander. In this example, direct heating is used, but indirect heating can also be achieved by adding a heat storage unit. The air reheating process is carried out in the renewable energy heat exchangers B1-B4.

[0047] Compared to systems without renewable energy heat exchange, the increased inlet temperature at each expander stage increases energy release and work output, promoting renewable energy utilization. Furthermore, due to the full utilization of heat, heat loss is reduced, improving system efficiency. During variable operating conditions, work output is varied by adjusting the pressure ratio of the booster compressor TC, correspondingly varying the input heat of renewable energy, and adjusting the stator angles of each expander stage.

[0048] Example 2

[0049] like Figure 2As shown, a supercharged thermal storage compressed air energy storage system with second-stage supercharging is provided. The system includes a compressor unit, an air storage device, a renewable energy heat exchange unit, an expansion unit, and a compression heat recovery device connected in sequence. The compressor unit includes a first compressor C1, a second compressor C2, a third compressor C3, and a fourth compressor C4. The air storage device is an air storage tank TA. Intercoolers A1-A4 are correspondingly provided for compressors C1-C4. The compression heat is recovered in the intercoolers A1-A4 and stored in a compression heat storage device, which is a heat storage tank TS. The heat storage medium in the heat storage tank TS is pressurized water. The renewable energy heat source reheat unit includes a first renewable energy heat exchanger B1, a second renewable energy heat exchanger B2, a third renewable energy heat exchanger B3, and a fourth renewable energy heat exchanger B4, which are respectively connected to renewable energy sources. The expansion unit includes a first-stage expander T1, a second-stage expander T2, a third-stage expander T3, and a fourth-stage expander T4 corresponding to the renewable energy heat exchangers B1-B4. A cooling gas D and a booster compressor TC are provided in sequence between the first-stage expander T1 and the second-stage expander T2. This embodiment also features a heat-of-compression reheat unit for heating the air before expansion machines T1-T4. This unit comprises a first heat-of-compression reheater R1, a second heat-of-compression reheater R2, a third heat-of-compression reheater R3, and a fourth heat-of-compression reheater R4. The unit is connected to a thermal storage tank TS and uses the heat of compression stored in the tank to heat the high-pressure air 6 boosted by the booster compressor. The heat storage medium in the tank is cooled and then stored in a normal-temperature storage tank CS. The normal-temperature storage tank CS is connected to an intercooler, through which the heat storage medium receives heat of compression recovered from intercoolers A1-A4. An aftercooler AC is located between the air storage tank TA and the fourth compressor C4. A main valve V is located between the air storage tank TA and the booster compressor TC. A normal-temperature circulating water pump 11 is located at the outlet of the normal-temperature storage tank CS, while a high-temperature circulating water pump 12 is located at the outlet of the thermal storage tank TS. A support shaft Z is located between the booster compressor and the second-stage expansion machine.

[0050] In the compressed air energy storage system provided in the above-mentioned embodiment, the booster compressor increases the pressure of the expander unit, thereby increasing the overall expansion ratio and maximizing the expander's heat absorption capacity after the pressure increase, thereby promoting the full utilization of compression heat and renewable energy heat. The booster-type thermal storage compressed air energy storage system provided in the above-mentioned embodiment can achieve efficient variable-mode operation by varying the booster compressor's pressure ratio and, accordingly, the amount of renewable energy heat absorbed, while maintaining the outlet temperature of each expander at near-ambient temperatures.

[0051] Workflow:

[0052] During the energy storage process, air 1 is compressed to a high pressure state by the multi-stage compressors C1-C4. The outlet air 2 of the multi-stage compressor is cooled by AC to form cooled high-pressure air 3 which is stored in the air storage tank TA. During this period, the compression heat is recovered in the intercoolers A1-A4 and stored in the heat storage tank TS. The heat storage medium is pressurized water.

[0053] During energy release, the high-pressure air in the air storage tank TA is released. The released high-pressure air 4 before the main valve passes through the main valve V to obtain high-pressure air 5 after the main valve. The high-pressure air 5 after the main valve first enters the first-stage compression heat reheater RI. The high-temperature air heated by the compression heat reheater R1 directly enters the first-stage expander T1. The first-stage expander outlet air 14 expanded by the first-stage expander T1 is cooled by the cooler D to obtain booster compressor inlet air 15, which enters the booster compressor TC. TC is a near-isothermal compressor whose power source is the work output of the second-stage expander T2. The high-pressure air 6 recompressed by the booster compressor TC enters the multi-stage expanders T2-T4 to expand and perform work, and is exhausted 13 at the end of the fourth-stage expander T4 at the very end. The air before each stage of the expander is reheated twice. The heat source for the first reheat is the heat of compression from the heat storage tank TS. The air reheating process is carried out in the heat of compression reheaters R2-R4. The high-temperature water in the heat storage tank TS is discharged by a high-temperature circulating water pump, passes through the heat of compression reheaters R1-R4 in sequence, and is then input into the normal-temperature water tank CS. The normal-temperature water in the normal-temperature water tank CS is discharged by a normal-temperature circulating water pump 11, flows through the intercoolers A1-A4 in sequence, absorbs the heat of compression recovered by A1-A4, and forms high-temperature water that is stored in the heat storage tank TS. The heat source for the second reheating is renewable energy heat 8-10, where 8 is the renewable energy heat input into the air before the second-stage expander, 9 is the renewable energy heat input into the air before the third-stage expander, and 10 is the renewable energy heat input into the air before the fourth-stage expander. In this example, direct heating is used, but indirect heating can also be achieved by adding a heat storage unit. The air reheating process is carried out in the renewable energy heat exchangers B2-B4.

[0054] Compared to a system without a renewable energy heat exchange process, the system's work output increases due to the increased inlet temperature of the last three expanders, promoting renewable energy utilization. System efficiency is also improved due to the reduced heat losses. However, due to the lack of a renewable energy heat exchanger before the first-stage expander, the work output of the system shown in this embodiment is reduced compared to Example 1. When the system operates under variable operating conditions, the booster compressor's pressure ratio and the renewable energy heat ratio can also be adjusted to achieve variable work output.

[0055] In summary, the booster compressor can change the system power output when it is in different positions. When its inlet and outlet are flexibly adjusted through the multi-way valve and pipeline flow direction, the range of change of the system power output will be wider.

[0056] Example 3

[0057] like Figure 3 As shown, a supercharged supercritical compressed air energy storage system with first-stage supercharging is provided. The system includes a compressor unit, a gas storage device, a renewable energy heat exchange unit, an expansion unit, and a compression heat recovery device connected in sequence. The compressor unit includes a first compressor C1, a second compressor C2, a third compressor C3, and a fourth compressor C4; the gas storage device is a liquid air storage tank CY, and an aftercooler AC and a liquid expander L are provided between the fourth compressor C4 and the liquid air storage tank CY. A cryogenic pump is provided at the outlet of the liquid air storage tank CY, and the gas and liquid states are converted through the cold storage / heat exchanger CE; intercoolers A1-A4 are provided corresponding to the compressors C1-C4, and the compression heat is recovered in the intercoolers A1-A4. The recovered heat is stored in a heat storage device for compression heat, which is a heat storage tank TS, and the heat storage medium is pressurized water at this time; the renewable energy heat source reheat unit includes a first renewable energy heat exchanger B1, a second renewable energy heat exchanger B2, a third renewable energy heat exchanger B3 and a fourth renewable energy heat exchanger B4, which are respectively connected to renewable energy; the expansion unit includes a first-stage expander T1, a second-stage expander T2, a third-stage expander T3 and a fourth-stage expander T4 corresponding to the renewable energy heat exchangers B1-B4; a booster compressor TC is provided between the liquid air storage tank CY and the first-stage expander T1. This embodiment also features a heat-of-compression reheat unit for heating the air before expansion machines T1-T4. This unit comprises a first heat-of-compression reheater R1, a second heat-of-compression reheater R2, a third heat-of-compression reheater R3, and a fourth heat-of-compression reheater R4. The unit is connected to a thermal storage tank TS and uses the heat of compression stored in the tank to heat the high-pressure air 6 boosted by the booster compressor. The heat storage medium in the tank TS is cooled and then stored in a normal-temperature tank CS. The normal-temperature tank CS is connected to an intercooler, through which the heat storage medium receives heat of compression recovered from intercoolers A1-A4. A main valve V is installed between the liquid air storage tank CY and the booster compressor TC. A normal-temperature circulating water pump 11 is installed at the outlet of the normal-temperature tank CS, and a high-temperature circulating water pump 12 is installed at the outlet of the thermal storage tank TS. A support shaft Z is provided between the booster compressor and the first-stage expansion machine.

[0058] In the compressed air energy storage system provided in the above-mentioned embodiment, the booster compressor increases the pressure of the expander unit, thereby increasing the overall expansion ratio and maximizing the expander's heat absorption capacity after the pressure increase, thereby promoting the full utilization of compression heat and renewable energy heat. The booster-type thermal storage compressed air energy storage system provided in the above-mentioned embodiment can achieve efficient variable-mode operation by varying the booster compressor's pressure ratio and, accordingly, the amount of renewable energy heat absorbed, while maintaining the outlet temperature of each expander at near-ambient temperatures.

[0059] Workflow:

[0060] During the energy storage process, air 1 is compressed to a high pressure state by multi-stage compressors C1-C4. The air 2 at the outlet of the multi-stage compressor is cooled by the aftercooler AC to form cooled high-pressure air 3. The cooled high-pressure air 3 is further cooled by the cold storage / heat exchanger to obtain liquid expander air 16. The air is then reduced in pressure by the liquid expander and converted into liquid expander air 17, which is stored in the liquid air storage tank CY. At the same time, the atmospheric pressure gaseous air 20 generated by the outlet of the liquid expander L is transported to the cold storage / heat exchanger to release the cooling capacity and form cold storage / heat exchanger exhaust 21 to be discharged to the atmosphere. During this period, the compression heat is recovered in the intercoolers A1-A4 and stored in the heat storage tank TS. The heat storage medium is pressurized water.

[0061] During the energy release process, the gaseous gas in the liquid gas storage tank CY is released, and the released liquid air 18 is pressurized to a high-pressure state by the cryogenic pump P to obtain the air after the cryogenic pump 19, which is then transported to the cold storage / heat exchanger. The high-pressure air before the main valve 4 after the cold is released passes through the main valve V to obtain the high-pressure air after the main valve 5. The high-pressure air after the main valve 5 enters the booster compressor TC. TC is a near-isothermal compressor, and its power source is the work output of the first-stage expander T1. The high-pressure air 6 compressed again by the booster compressor TC enters the multi-stage expanders T1-T4 to expand and perform work, and is exhausted 13 at the end of the fourth-stage expander T4 at the very end. The air before each expander stage is reheated twice. The first reheating heat source is the heat of compression from the heat storage tank TS. The air reheating process is carried out in the compression heat reheaters R1-R4. The high-temperature water in the heat storage tank TS is discharged by a high-temperature circulating water pump, passes through the compression heat reheaters R1-R4 in sequence, and is then input into the normal-temperature water tank CS. The normal-temperature water in the normal-temperature water tank CS is discharged by a normal-temperature circulating water pump 11, flows through the intercoolers A1-A4 in sequence, absorbs the compression heat recovered by A1-A4, and forms high-temperature water, which is stored in the heat storage tank TS. The second reheating heat source is renewable energy heat 7-10, where 7 is the renewable energy heat input into the air before the first-stage expander, 8 is the renewable energy heat input into the air before the second-stage expander, 9 is the renewable energy heat input into the air before the third-stage expander, and 10 is the renewable energy heat input into the air before the fourth-stage expander. In this example, direct heating is used, but indirect heating can also be achieved by adding a heat storage unit. The air reheating process is carried out in the renewable energy heat exchangers B1-B4.

[0062] Compared with the system without renewable energy heat exchange process, the energy release work output is increased due to the increase in the inlet temperature of the expanders at all levels, which promotes the utilization of renewable energy, and due to the full utilization of heat, the heat loss is reduced and the system efficiency is improved. When the system is running under variable working conditions, the work output is changed by adjusting the pressure ratio of the booster compressor TC and correspondingly changing the input heat of renewable energy, and adjusting the stator angles of the expanders at all levels. Compared with the traditional supercritical compressed air energy storage system (the energy release pressure is significantly lower than the energy storage pressure), this system is conducive to the absorption of compression heat and renewable energy heat after the energy release pressure is increased under the action of the booster compressor, which will effectively improve the system efficiency. The variable working condition operation of the system is the same as the adjustment process of Example 1, which also adjusts the pressure ratio of the booster compressor and the heat of renewable energy.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention. The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and variations without departing from the technical principles of the present invention, and such improvements and variations shall also be considered within the scope of protection of the present invention.

Claims

1. A supercharged compressed air energy storage system, characterized in that: The system includes a compressor unit, a gas storage device, a renewable energy heat exchange unit, an expansion unit and a compression heat recovery device connected in sequence. The compressor unit includes a plurality of compressors; The expander group includes a plurality of expanders; The expansion unit is connected to a booster compressor to increase the total expansion ratio. The booster compressor is arranged before any expander and is used to selectively absorb the heat of renewable energy between the stages of the expander group; The renewable energy heat exchange unit includes a plurality of renewable energy heat exchangers, The booster compressor is driven by a motor or an expander. The compressor includes one or more stages of compressors; the expander includes one or more stages of expanders.

2. The pressurized compressed air energy storage system according to claim 1, characterized in that: The compressor includes one or more compressors selected from a piston compressor, a centrifugal compressor, an axial compressor, a screw compressor and a rotary compressor; The renewable energy heat exchanger includes one or more heat exchangers selected from shell and tube heat exchangers, plate-fin heat exchangers, plate heat exchangers, spiral tube heat exchangers, double-tube heat exchangers, plate-shell heat exchangers, tube-fin heat exchangers and heat pipe heat exchangers.

3. The pressurized compressed air energy storage system according to claim 1, characterized in that: The expander includes one selected from a piston expander, an axial flow expander, a centrifugal expander, a screw expander or a hybrid expander.

4. The pressurized compressed air energy storage system according to claim 1, characterized in that: The driving energy of the compressor includes one or a combination of two energy sources selected from grid electricity and renewable energy electricity.

5. The boosted compressed air energy storage system according to claim 1, characterized in that: The booster compressor includes one selected from a piston compressor, an axial compressor, a centrifugal compressor, a screw compressor or a hybrid compressor.

6. The pressurized compressed air energy storage system according to claim 1, characterized in that: The booster compressor adopts an isothermal compression mode.

7. The pressurized compressed air energy storage system according to claim 1, characterized in that: The system further comprises a compression heat storage device, wherein the heat storage material in the compression heat storage device comprises one or more selected from water, thermal oil and phase change material.

8. The pressurized compressed air energy storage system according to claim 1, characterized in that: The system further includes a renewable energy heat accumulator disposed between the renewable energy heat source reheat unit and the expansion unit for smoothing heat fluctuations generated by the renewable energy heat source reheat unit; The heat storage material in the renewable energy heat accumulator includes one or two heat storage materials selected from thermal oil and molten salt.

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