A multi-stage pressure-stabilizing cavern-type adiabatic compressed air energy storage power station system

Abstract

A multi-stage pressure-stabilizing cavern-type adiabatic compressed air energy storage power station system, wherein a low-pressure compressor is connected to the low-pressure turbine part of the expander, a medium-pressure compressor is connected to the medium-pressure turbine part of the expander, and a high-pressure compressor is connected to the high-pressure turbine part of the expander; and a first integrated oil-gas heat exchanger for heat charging and heat release is arranged at the front end of the air inlet side of the high-pressure turbine part of the expander, a second integrated oil-gas heat exchanger for heat charging and heat release is arranged between the high-pressure turbine part of the expander and the medium-pressure turbine part of the expander, and a third integrated oil-gas heat exchanger for heat charging and heat release is arranged between the medium-pressure turbine part of the expander and the low-pressure turbine part of the expander; it also includes an air storage device, the air storage device includes a high-pressure air storage chamber, a medium-pressure air storage chamber and a low-pressure air storage chamber, wherein the outlet of the high-pressure air storage chamber is connected to the first integrated oil-gas heat exchanger for heat charging and heat release through the high-pressure air storage chamber inlet / outlet valve; the air inlet end of the medium-pressure compressor is connected to the low-pressure air storage chamber, and the air inlet end of the high-pressure compressor is connected to the medium-pressure air storage chamber. The present invention reduces the range of variation in the compressor's intake parameters and back pressure, partially achieving pressure-stabilized operation during the compression process, improving the efficiency of the energy storage compression process, and thereby increasing the electricity-to-electricity conversion efficiency throughout the entire process of the adiabatic compressed air energy storage power station by at least 5%.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system energy storage, and in particular relates to a multi-stage voltage-stabilizing cave-type adiabatic compressed air energy storage power station system. Background Art

[0002] As my country advances its carbon peak and carbon neutrality strategy, the shift in energy mix from fossil fuels to renewable energy is accelerating, and new energy sources are rapidly developing. However, due to the intermittent, cyclical, and volatile nature of wind and solar power output, the phenomenon of wind and solar power curtailment is becoming increasingly serious. To address the challenges of accommodating new energy sources and improve the safety and stability of power systems, the development of large-scale energy storage technologies is imperative. Compressed air energy storage technology, with its large storage capacity, long storage cycle, high system efficiency, long operating life, and low specific investment, is considered one of the most promising large-scale energy storage technologies.

[0003] Adiabatic compressed air energy storage achieves higher compressed air temperature and higher-quality heat of compression by increasing the single-stage compression ratio of the compressor during the compression process. This decouples and stores the pressure potential energy and compression heat energy. During energy release, the heat of compression is fed back to the high-pressure air using a heat storage device, achieving a coupled release of the air's pressure potential energy and compression heat energy, improving the overall efficiency of the system.

[0004] However, during the operation of the current adiabatic compressed air energy storage system, the pressure in the air storage chamber constantly changes, causing the compressor to operate under variable back pressure conditions for a long time, affecting the operating efficiency of the compressor, and thus affecting the circulation efficiency and operating performance of the entire compressed air energy storage system. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: how to improve the operating efficiency of the compressor, and therefore provides a multi-stage pressure-stabilizing cavern-type adiabatic compressed air energy storage power station system.

[0006] To achieve the above object, the present invention is achieved through the following technical solutions:

[0007] A multi-stage pressure-stabilized cavern-type adiabatic compressed air energy storage power station system includes a compression device consisting of a low-pressure compressor, a medium-pressure compressor, and a high-pressure compressor, wherein the low-pressure compressor is connected to the low-pressure turbine part of the expander, the medium-pressure compressor is connected to the medium-pressure turbine part of the expander, and the high-pressure compressor is connected to the high-pressure turbine part of the expander; and a first integrated oil-gas heat exchanger for heat charging and heat dissipation is provided at the front end of the air inlet side of the high-pressure turbine part of the expander, and a heat exchanger is provided between the high-pressure turbine part of the expander and the medium-pressure turbine part of the expander. A second integrated oil-gas heat exchanger for heat charging and release is provided, and a third integrated oil-gas heat exchanger for heat charging and release is provided between the medium-pressure turbine part of the expander and the low-pressure turbine part of the expander; it also includes an air storage device, which includes a high-pressure air storage chamber, a medium-pressure air storage chamber and a low-pressure air storage chamber, wherein the outlet of the high-pressure air storage chamber is connected to the first integrated oil-gas heat exchanger for heat charging and release through the high-pressure air storage chamber inlet / outlet valve; the air inlet end of the medium-pressure compressor is connected to the low-pressure air storage chamber, and the air inlet end of the high-pressure compressor is connected to the medium-pressure air storage chamber.

[0008] The preset pressure of the low-pressure air storage chamber is equal to the rated exhaust pressure of the low-pressure compressor, and is also equal to the rated intake pressure of the medium-pressure compressor; the preset pressure of the medium-pressure air storage chamber is equal to the rated exhaust pressure of the medium-pressure compressor, and is also equal to the rated intake pressure of the high-pressure compressor; the preset pressure of the high-pressure air storage chamber is equal to the rated exhaust pressure of the high-pressure compressor.

[0009] A medium-pressure compressor bypass valve is provided on the connecting pipeline between the low-pressure air storage chamber and the medium-pressure air storage chamber, and a high-pressure compressor bypass valve is provided on the connecting pipeline between the medium-pressure air storage chamber and the high-pressure air storage chamber.

[0010] The air inlet side of the low-pressure compressor is provided with a low-pressure compressor air inlet valve, and its outlet side is connected to the low-pressure turbine part of the expander through the provided low-pressure compressor outlet valve and the expander low-pressure turbine air inlet valve; the air inlet side of the medium-pressure compressor is connected to the low-pressure air storage chamber through the medium-pressure compressor air inlet valve, and the outlet side of the medium-pressure compressor is connected to the medium-pressure turbine part of the expander through the provided medium-pressure compressor outlet valve and the expander medium-pressure turbine air inlet valve, and the outlet side of the expander medium-pressure turbine part is provided with an expander medium-pressure turbine outlet valve; the air inlet side of the high-pressure compressor is connected to the medium-pressure air storage chamber through the high-pressure compressor air inlet valve, and the outlet side of the high-pressure compressor is connected to the high-pressure turbine part of the expander through the provided high-pressure compressor outlet valve and the expander high-pressure turbine air inlet valve, and the outlet side of the high-pressure turbine part of the expander is connected to the expander high-pressure turbine outlet valve.

[0011] The third integrated oil-gas heat exchanger for charging and releasing heat is connected to the low-pressure air storage chamber through the low-pressure air through the outlet valve after the heat exchanger; the second integrated oil-gas heat exchanger for charging and releasing heat is connected to the medium-pressure air storage chamber through the medium-pressure air through the outlet valve after the heat exchanger.

[0012] It also includes a high-level normal-pressure and high-temperature oil storage tank, a low-level normal-pressure and low-temperature oil storage chamber and an oil-water cooler, wherein the first integrated oil-gas heat exchanger for heat charging and releasing, the second integrated oil-gas heat exchanger for heat charging and releasing and the third integrated oil-gas heat exchanger for heat charging and releasing are all connected to the high-level normal-pressure and high-temperature oil storage tank and the oil-water cooler, and the oil-water cooler is connected to the low-level normal-pressure and low-temperature oil storage chamber.

[0013] The first integrated oil-gas heat exchanger for charging and releasing heat is connected to the high-level normal-pressure and high-temperature oil storage tank through the hot oil side valve of the first oil-gas heat exchanger, and the first integrated oil-gas heat exchanger for charging and releasing heat is connected to the oil-water cooler through the cold oil side valve of the first oil-gas heat exchanger; the second integrated oil-gas heat exchanger for charging and releasing heat is connected to the high-level normal-pressure and high-temperature oil storage tank through the hot oil side valve of the second oil-gas heat exchanger, and the second integrated oil-gas heat exchanger for charging and releasing heat is connected to the oil-water cooler through the cold oil side valve of the second oil-gas heat exchanger; the third integrated oil-gas heat exchanger for charging and releasing heat is connected to the high-level normal-pressure and high-temperature oil storage tank through the hot oil side valve of the third oil-gas heat exchanger, and the third integrated oil-gas heat exchanger for charging and releasing heat is connected to the oil-water cooler through the cold oil side valve of the third oil-gas heat exchanger.

[0014] A high-temperature oil storage tank inlet valve is provided on the inlet side of the high-level normal-pressure high-temperature oil storage tank, and the high-temperature oil storage tank inlet valve is provided on the hot oil main pipe; a hot oil pump inlet valve, a hot oil pump, a hot oil pump outlet check valve and a hot oil pump outlet shut-off valve are provided in sequence on its outlet side; a low-level normal-pressure low-temperature oil storage chamber inlet valve is provided on the inlet side of the low-level normal-pressure low-temperature oil storage chamber, and a cold oil pump inlet valve, a cold oil pump, a cold oil pump outlet check valve and a cold oil pump outlet shut-off valve are provided in sequence on its outlet side.

[0015] Oil-water cooler bypass valves are installed at both ends of the oil-water cooler.

[0016] Three integrated oil-gas heat exchangers for heat charging and discharging are connected to the hot oil main pipe and the cold oil main pipe respectively, and a hot and cold oil connecting valve is provided between the hot oil main pipe and the cold oil main pipe.

[0017] Compared with existing technologies, the present invention has the following advantages: It provides a multi-stage, pressure-stabilized, cavern-type adiabatic compressed air energy storage power station system, which includes three cavern-type air storage chambers: high, medium, and low pressure. First, it fully utilizes favorable rock conditions and provides a larger container space in stages. This reduces investment while also reducing the range of variation in the compressor's intake parameters and back pressure. This partially achieves pressure-stabilized operation during the compression process, improving the efficiency of the energy storage compression process and, consequently, increasing the electricity-to-electricity conversion efficiency of the entire adiabatic compressed air energy storage power station by at least 5%. Second, it utilizes an integrated oil-to-gas heat exchanger for heat charging and discharging, further reducing primary investment. Third, it utilizes a low-pressure ratio compressor to effectively control the ratio of mechanical energy converted to thermal energy during the compression process, improving the energy conversion efficiency of the equipment itself. Furthermore, the compressed air temperature after pressurization is controlled to approximately 250°C, improving the quality of recovered heat, reducing high-grade energy loss during the energy conversion process, and increasing electricity-to-electricity conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a system flow chart of the present invention. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0021] like Figure 1 As shown, a multi-stage pressure-stabilized cavern-type adiabatic compressed air energy storage power station system includes a compression device consisting of a low-pressure compressor 6, an intermediate-pressure compressor 7, and a high-pressure compressor 8. The low-pressure compressor 6 is connected to the low-pressure turbine part 11 of the expander, the intermediate-pressure compressor 7 is connected to the intermediate-pressure turbine part 10 of the expander, and the high-pressure compressor 8 is connected to the high-pressure turbine part 9 of the expander; and a first integrated oil-gas heat exchanger 12 for charging and discharging heat is provided at the front end of the air inlet side of the high-pressure turbine part 9 of the expander, and a heat exchanger 12 for discharging heat is provided between the high-pressure turbine part 9 of the expander and the intermediate-pressure turbine part 10 of the expander. A second integrated heat-charging and heat-releasing oil-gas heat exchanger 13 is provided, and a third integrated heat-charging and heat-releasing oil-gas heat exchanger 14 is provided between the expander's medium-pressure turbine section 10 and the expander's low-pressure turbine section 11. The system also includes a gas storage device comprising a high-pressure gas storage chamber 3, a medium-pressure gas storage chamber 2, and a low-pressure gas storage chamber 1. The outlet of the high-pressure gas storage chamber 3 is connected to the first integrated heat-charging and heat-releasing oil-gas heat exchanger 12 via a high-pressure gas storage chamber inlet / outlet valve 28. The air inlet of the medium-pressure compressor 7 is connected to the low-pressure gas storage chamber 1, and the air inlet of the high-pressure compressor 8 is connected to the medium-pressure gas storage chamber 2. The above devices form an energy storage system, an energy release system, and a heat exchange and storage system, collectively realizing the functions of a multi-stage, pressure-stabilized, cave-type, adiabatic compressed air energy storage power station system.

[0022] It should be noted that the expander unit comprises a coaxial multi-stage air turbine expander and generator, including the expander low-pressure turbine section 11, the expander medium-pressure turbine section 10, and the expander high-pressure turbine section 9. The expander unit's intake pressure is the pressure of the high-pressure air storage chamber, and its exhaust pressure is atmospheric pressure. Depending on grid needs, the multi-stage air turbine expander unit can also be divided into three smaller-capacity, non-coaxial units to further improve operational flexibility and low-load power generation efficiency.

[0023] The air storage device includes a low-pressure air storage chamber 1, an intermediate-pressure air storage chamber 2, and a high-pressure air storage chamber 3. The preset pressure of the low-pressure air storage chamber 1 is equal to the rated exhaust pressure of the low-pressure compressor 6 and the rated intake pressure of the intermediate-pressure compressor 7, and is approximately 0.45 to 0.5 MPa. The preset pressure of the intermediate-pressure air storage chamber 2 is equal to the rated exhaust pressure of the intermediate-pressure compressor 7 and the rated intake pressure of the high-pressure compressor 8, and is approximately 2.0 to 2.5 MPa. The preset pressure of the high-pressure air storage chamber 3 is equal to the rated exhaust pressure of the high-pressure compressor 8, and is approximately 9.0 to 12.5 MPa.

[0024] Furthermore, a medium-pressure compressor bypass valve 21 is provided on the connecting pipeline between the low-pressure air storage chamber 1 and the medium-pressure air storage chamber 2, and a high-pressure compressor bypass valve 22 is provided on the connecting pipeline between the medium-pressure air storage chamber 2 and the high-pressure air storage chamber 3.

[0025] The inlet side of the low-pressure compressor 6 is equipped with a low-pressure compressor inlet valve 18. Its outlet is connected to the expander low-pressure turbine section 11 via a low-pressure compressor outlet valve 19 and an expander low-pressure turbine inlet valve 33. The inlet side of the intermediate-pressure compressor 7 is connected to the low-pressure air storage chamber 1 via an intermediate-pressure compressor inlet valve 23. The outlet side of the intermediate-pressure compressor 7 is connected to the expander intermediate-pressure turbine section 10 via an intermediate-pressure compressor outlet valve 24 and an expander intermediate-pressure turbine inlet valve 31. The outlet side of the expander intermediate-pressure turbine section 10 is equipped with an expander intermediate-pressure turbine outlet valve 32. The intake side of the high-pressure compressor 8 is connected to the medium-pressure air storage chamber 2 through the high-pressure compressor intake valve 26, and the outlet side of the high-pressure compressor 8 is connected to the expander high-pressure turbine part 9 through the set high-pressure compressor outlet valve 27 and the expander high-pressure turbine intake valve 29. The outlet side of the expander high-pressure turbine part 9 is connected to the expander high-pressure turbine outlet valve 30.

[0026] Furthermore, the low-pressure compressor 6 , the intermediate-pressure compressor 7 and the high-pressure compressor 8 are all equipped with independent drive motors.

[0027] Furthermore, the pressure ratios of the high, medium and low pressure compressors are substantially the same, and are between 4.5 and 5.0.

[0028] Furthermore, the third integrated oil-gas heat exchanger 14 for charging and releasing heat is connected to the low-pressure air storage chamber 1 through the low-pressure air via the heat exchanger rear outlet valve 20; the second integrated oil-gas heat exchanger 13 for charging and releasing heat is connected to the medium-pressure air storage chamber 2 through the medium-pressure air via the heat exchanger rear outlet valve 25.

[0029] The heat exchange device includes a first integrated oil-gas heat exchanger 12 for heat charging and discharging, a second integrated oil-gas heat exchanger 13 for heat charging and discharging, and a third integrated oil-gas heat exchanger 14 for heat charging and discharging. All three oil-gas heat exchangers use high-temperature synthetic thermal oil as the heat exchange and storage medium. During compression, the low-temperature thermal oil absorbs the heat of compression from the high-pressure air through the oil-gas heat exchanger and is stored. During expansion, the high-temperature thermal oil heats the high-pressure air through the oil-gas heat exchanger for expansion work. Before entering the low-temperature oil storage chamber, the thermal oil is further cooled by an oil-water cooler. The use of an integrated oil-gas heat exchanger for heat charging and discharging allows the compression and expansion processes to share a heat exchanger, saving the cost of the heat exchange system equipment.

[0030] The above-mentioned heat exchange device also includes a high-level normal-pressure high-temperature oil storage tank 5, a low-level normal-pressure low-temperature oil storage chamber 4 and an oil-water cooler 15, wherein the first integrated heat-charging and heat-releasing oil-gas heat exchanger 12, the second integrated heat-charging and heat-releasing oil-gas heat exchanger 13 and the third integrated heat-charging and heat-releasing oil-gas heat exchanger 14 are all connected to the high-level normal-pressure high-temperature oil storage tank 5 and the oil-water cooler 15, and the oil-water cooler 15 is connected to the low-level normal-pressure low-temperature oil storage chamber 4. The present invention makes full use of rock conditions. The low-level normal-pressure low-temperature oil storage chamber 4 is used to store low-temperature thermal oil; the high-level normal-pressure high-temperature oil storage tank 5 is used to store high-temperature thermal oil. During the implementation of the project, the function of the low-level normal-pressure low-temperature oil storage chamber 4 can be replaced by a high-level normal-pressure low-temperature oil storage tank according to actual conditions, without affecting the realization of the overall function of the system.

[0031] Furthermore, the first integrated oil-gas heat exchanger 12 for charging and releasing heat is connected to the high-level normal-pressure and high-temperature oil storage tank 5 through the first oil-gas heat exchanger hot oil side valve 43, and the first integrated oil-gas heat exchanger 12 for charging and releasing heat is connected to the oil-water cooler 15 through the first oil-gas heat exchanger cold oil side valve 40; the second integrated oil-gas heat exchanger 13 for charging and releasing heat is connected to the high-level normal-pressure and high-temperature oil storage tank 5 through the second oil-gas heat exchanger hot oil side valve 42, and the second integrated oil-gas heat exchanger 13 for charging and releasing heat is connected to the oil-water cooler 15 through the second oil-gas heat exchanger cold oil side valve 39; the third integrated oil-gas heat exchanger 14 for charging and releasing heat is connected to the high-level normal-pressure and high-temperature oil storage tank 5 through the third oil-gas heat exchanger hot oil side valve 41, and the third integrated oil-gas heat exchanger 14 for charging and releasing heat is connected to the oil-water cooler 15 through the third oil-gas heat exchanger cold oil side valve 38.

[0032] Furthermore, a high-temperature oil storage tank inlet valve 44 is provided on the inlet side of the high-level normal-pressure high-temperature oil storage tank 5, and the high-temperature oil storage tank inlet valve 44 is provided on the hot oil main pipe; a hot oil pump inlet valve 45, a hot oil pump 17, a hot oil pump outlet check valve 46 and a hot oil pump outlet shut-off valve 47 are provided in sequence on its outlet side; a low-level normal-pressure low-temperature oil storage chamber 4 is provided with a low-temperature oil storage chamber inlet valve 48 on the inlet side, and a cold oil pump inlet valve 34, a cold oil pump 16, a cold oil pump outlet check valve 35 and a cold oil pump outlet shut-off valve 36 are provided on its outlet side in sequence.

[0033] Furthermore, oil-water cooler bypass valves 37 are provided at both ends of the oil-water cooler 15 .

[0034] Furthermore, three integrated oil-gas heat exchangers for heat charging and discharging are respectively connected to the hot oil main pipe and the cold oil main pipe, and a hot and cold oil connecting valve 49 is provided between the hot oil main pipe and the cold oil main pipe.

[0035] The operating principle of this invention is as follows: it utilizes three air storage chambers (high, medium, and low pressure) in conjunction with a compressor, expander, and heat exchange and storage system to construct a multi-stage, pressure-stabilized, cavern-type, adiabatic compressed air energy storage power station system. This system enables the transfer and conversion of energy between electrical energy, thermal energy, mechanical energy, and pressure potential energy. This invention is suitable for deployment in areas with good rock conditions where cavern-type air storage chambers can be constructed.

[0036] The working process of the present invention is:

[0037] The process system flow is mainly divided into the initial preparation stage, energy release stage and energy storage stage.

[0038] Figure 1 The solid line in the figure represents the air medium, and the dotted line represents the heat transfer oil medium.

[0039] Initial preparation stage example:

[0040] Open the low-pressure compressor inlet valve 18, the low-pressure compressor outlet valve 19, the low-pressure air outlet valve 20 after passing through the heat exchanger, the medium-pressure compressor bypass valve 21, and the high-pressure compressor bypass valve 22, start the low-pressure compressor 6, and inhale air from the environment to inject air and increase the pressure of the low-pressure air storage chamber 1, the medium-pressure air storage chamber 2, and the high-pressure air storage chamber 3. When the pressure of each air storage chamber reaches the preset pressure of the low-pressure air storage chamber, close the medium-pressure compressor bypass valve 21. At this time, the low-pressure preset is completed.

[0041] Open the medium-pressure compressor inlet valve 23, the medium-pressure compressor outlet valve 24, and the medium-pressure air outlet valve 25 after passing through the heat exchanger, start the medium-pressure compressor 7, and the medium and low-pressure compressors simultaneously inject air into the medium-pressure air storage chamber 2 and the high-pressure air storage chamber 3 to increase the pressure. During this process, the low-pressure air storage chamber 1 plays a pressure stabilizing role. When the pressures in the medium-pressure air storage chamber 2 and the high-pressure air storage chamber 3 reach the preset pressure of the medium-pressure air storage chamber, close the high-pressure compressor bypass valve 22. At this time, the medium-pressure preset is completed.

[0042] Open the high-pressure compressor inlet valve 26, the high-pressure compressor outlet valve 27, and the high-pressure air storage chamber inlet and outlet valves 28, start the high-pressure compressor 8, and the high, medium and low-pressure compressors simultaneously inject air into the high-pressure air storage chamber 3 to increase the pressure. During this process, the low-pressure air storage chamber 1 and the medium-pressure air storage chamber 2 play a pressure stabilizing role. When the pressure in the high-pressure air storage chamber 3 reaches the preset pressure of the high-pressure air storage chamber, the low-pressure compressor 6, the medium-pressure compressor 7, and the high-pressure compressor 8 stop working, and close the low-pressure compressor outlet valve 19, the low-pressure air outlet valve 20 after passing through the heat exchanger, the medium-pressure compressor outlet valve 24, the medium-pressure air outlet valve 25 after passing through the heat exchanger, the high-pressure compressor outlet valve 27 and the high-pressure air storage chamber inlet and outlet valves 28. At this time, the high-pressure preset is completed.

[0043] At the start of the initial preparation phase, the cold oil pump inlet valve 34, cold oil pump outlet shutoff valve 36, oil-water cooler bypass valve 37, third oil-gas heat exchanger cold oil-side valve 38, second oil-gas heat exchanger cold oil-side valve 39, first oil-gas heat exchanger cold oil-side valve 40, third oil-gas heat exchanger hot oil-side valve 41, second oil-gas heat exchanger hot oil-side valve 42, first oil-gas heat exchanger hot oil-side valve 43, and high-temperature oil storage tank inlet valve 44 are kept open. Simultaneously with the low-pressure compressor startup, cold oil pump 16 is also turned on. Heat transfer oil flows out of the low-pressure, atmospheric, and low-temperature oil storage chamber 4, passes through the oil-water cooler bypass valve 37, and then is absorbed by the third, second, and first integrated oil-gas heat exchangers 14, 13, and 12, where it generates heat during the compressor compression process. Heat is then stored in the high-pressure, atmospheric, and high-temperature oil storage tank 5.

[0044] Through the above process, the electrical energy is converted into pressure potential energy and compression heat energy. At this time, the pressure potential energy is stored in the air storage chamber in the form of high-pressure air, and the compression heat energy is stored in the high-temperature oil tank in the form of high-temperature thermal oil.

[0045] Example of energy release and power generation stage:

[0046] During the peak period of external electricity consumption, the high-pressure air storage chamber inlet and outlet valves 28, the expander high-pressure turbine inlet valve 29, the expander high-pressure turbine outlet valve 30, the expander medium-pressure turbine inlet valve 31, the expander medium-pressure turbine outlet valve 32, and the expander low-pressure turbine inlet valve 33 are opened, and the coaxial multi-stage air turbine expander unit is turned on. The high-pressure air in the high-pressure air storage chamber 3 is discharged into the atmosphere after the expander generates power.

[0047] At the beginning of the energy release stage, keep the hot oil pump inlet valve 45, the hot oil pump outlet shut-off valve 47, and the low-temperature oil storage chamber inlet valve 48 open, start the hot oil pump 17, and the high-temperature heat transfer oil exchanges heat with the air through the first integrated heat charging and discharging oil-gas heat exchanger 12, the second integrated heat charging and discharging oil-gas heat exchanger 13, and the third integrated heat charging and discharging oil-gas heat exchanger 14. After the heat transfer oil releases heat and cools down, it is cooled again through the oil-water cooler 15 and then stored in the low-level normal pressure low-temperature oil storage chamber 4.

[0048] Through the above process, the conversion of pressure potential energy and compression heat energy into electrical energy is achieved.

[0049] Energy storage stage example:

[0050] When the external power grid has excess electricity and needs to store power, the low-pressure compressor 6, the intermediate-pressure compressor 7, the high-pressure compressor 8, and the cooling oil pump 16 are turned on. The low-pressure compressor draws air from the environment and compresses it. After being stabilized in the low-pressure air storage chamber 1, the air enters the intermediate-pressure compressor 7 for compression. After being stabilized again in the intermediate-pressure air storage chamber 2, the air is compressed by the high-pressure compressor 8 and stored in the high-pressure air storage chamber 3.

[0051] At the same time, the compressed high-temperature and high-pressure air enters the third integrated oil-gas heat exchanger 14 for charging and releasing heat, the second integrated oil-gas heat exchanger 13 for charging and releasing heat, and the first integrated oil-gas heat exchanger 12 for charging and releasing heat to exchange heat with the heat transfer oil. After the heat transfer oil absorbs heat and rises in temperature, it enters the high-level normal-pressure and high-temperature oil storage tank 5.

[0052] Through the above process, electrical energy is converted into pressure potential energy and compression heat energy. After the energy storage phase ends, the next energy release and power generation phase begins, completing the entire energy storage-power generation cycle.

[0053] The compression device in this invention comprises three air compressors with independent drive motors: a high-pressure compressor, an intermediate-pressure compressor, and a low-pressure compressor. The high-, intermediate-, and low-pressure compressors have essentially the same pressure ratio. Each air compressor can be a single high-power compressor or multiple low-power compressors operating in parallel. Shutoff valves are installed at the compressor inlet and outlet, enabling flexible scheduling during the initial preparation and energy storage phases.

[0054] The expansion device in this invention comprises a coaxial multi-stage air turbine expander unit, which includes a high-pressure turbine section, an intermediate-pressure turbine section, a low-pressure turbine section, and a generator. Together with the turbine inlet and outlet valves, these units enable the system's energy release process. Alternatively, the multi-stage air turbine expander unit can be split into three smaller, non-coaxial units, depending on grid needs, further improving operational flexibility and low-load power generation efficiency.

[0055] The gas storage device of the present invention includes three cavern-type gas storage chambers of high, medium and low pressure. Shut-off valves are provided at the inlet and outlet of the gas storage chambers to realize the storage of pressure potential energy. In the initial preparation stage, the compressor is started to compress the air to realize the pressure preset of the high, medium and low pressure gas storage chambers. In the energy release stage, the high-pressure air in the high-pressure gas storage chamber is released to the expander for expansion and work. In the energy storage stage, the high, medium and low pressure compressors are turned on at the same time, and the air in the environment is compressed to high pressure and then stored in the high-pressure gas storage chamber. During this process, the low-pressure gas storage chamber and the medium-pressure gas storage chamber can play a role in stabilizing pressure.

[0056] In this invention, thermal oil is used as the heat exchange and storage medium. The heat exchange device includes three sets of integrated oil-gas heat exchangers for heat charging and discharging, and one set of oil-water coolers. During the initial preparation and energy storage stages, the high-temperature air generated by the operation of the low, medium, and high-pressure compressors enters the corresponding oil-gas heat exchangers to exchange heat with the thermal oil. The thermal oil, after absorbing heat and heating, enters the high-temperature oil storage tank for storage. During the energy release stage, before entering each turbine stage, the air first passes through the corresponding oil-gas heat exchanger to be heated by the high-temperature thermal oil, and then enters the turbine to expand and perform work. After releasing heat and cooling, the thermal oil is cooled again by the oil-water cooler and then enters the low-temperature oil storage chamber for storage.

[0057] In the present invention, thermal oil is used as the heat exchange and heat storage medium. The heat storage device includes a high-position, atmospheric-pressure, high-temperature oil storage tank and a low-position, atmospheric-pressure, low-temperature cave-type oil storage chamber (the low-position, atmospheric-pressure, low-temperature cave-type oil storage chamber can also be replaced with a high-position, atmospheric-pressure, low-temperature oil storage tank according to actual conditions, and will not be repeated hereafter), as well as a hot oil pump and a cold oil pump connecting the heat storage system and the heat exchange system. During the initial preparation and energy storage stages, the cold oil pump transports the low-temperature thermal oil in the low-temperature oil storage chamber to the heat exchange system to absorb heat, and then returns to the high-temperature oil storage tank to store the heat. During the energy release stage, the hot oil pump transports the high-temperature thermal oil in the high-temperature oil storage tank to the heat exchange system to release heat, and then returns to the low-temperature oil storage chamber for storage. At the same time, during necessary stages such as system maintenance, the hot oil pump and its front and rear valves and the high-temperature oil storage tank inlet valve can be opened to achieve circulation of the heat transfer oil in the high-temperature oil storage tank to avoid solidification; the cold oil pump and its front and rear valves and the low-temperature oil storage chamber inlet valve can be opened to achieve circulation of the heat transfer oil in the low-temperature oil storage chamber to avoid solidification; the connecting valves of the hot oil main pipe and the cold oil main pipe can be opened to achieve circulation of the heat transfer oil in the system pipeline.

[0058] In the present invention, the high, medium and low pressure gas storage chambers and the low-level normal pressure and low temperature gas storage chamber are all realized by constructing artificial caves. Other devices such as the compression device, expansion device, heat exchange device and high-level normal pressure and high temperature oil storage tank are all arranged in the ground area.

[0059] Beneficial effects of this patent:

[0060] Current adiabatic compressed air energy storage systems typically utilize a coaxial multi-stage air compressor unit with only one high-pressure air storage chamber. During actual operation, the constant fluctuations in the air storage chamber pressure can affect the compressor's performance and efficiency.

[0061] The present invention comprises a low-pressure compressor, a medium-pressure compressor, and a high-pressure compressor each having an essentially identical pressure ratio and independently driven by an electric motor, and three air storage chambers for high, medium, and low pressure. During the energy storage phase, the low-pressure air storage chamber provides a stable backpressure for the low-pressure compressor, ensuring its operating efficiency. The low-pressure and medium-pressure air storage chambers provide stable intake parameters and backpressure for the medium-pressure compressor, ensuring its operating efficiency. The medium-pressure and high-pressure air storage chambers provide relatively stable intake parameters and backpressure for the high-pressure compressor, ensuring its operating efficiency.

[0062] In summary, the present invention improves to a certain extent the problem of reduced efficiency in the current adiabatic compressed air energy storage system during variable operating conditions, establishes a new multi-stage pressure-stabilized cave-type adiabatic compressed air energy storage power station system, and improves the overall efficiency of the adiabatic compressed air energy storage power station.

[0063] At the same time, the present invention adopts an integrated oil-gas heat exchanger for heat charging and discharging, so that the compression process and the expansion process share the heat exchanger, saving the cost of the heat exchange system equipment and having economic advantages.

[0064] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several changes and improvements can be made without departing from the overall concept of the present invention, and these should also be regarded as the scope of protection of the present invention.

Claims

1. A multi-stage pressure-stabilizing cavern-type adiabatic compressed air energy storage power station system, characterized by: The invention comprises a compression device consisting of a low-pressure compressor (6), an intermediate-pressure compressor (7) and a high-pressure compressor (8), wherein the low-pressure compressor (6) is connected to the low-pressure turbine part (11) of the expander, the intermediate-pressure compressor (7) is connected to the intermediate-pressure turbine part (10) of the expander, and the high-pressure compressor (8) is connected to the high-pressure turbine part (9) of the expander; and a first heat-charging and heat-discharging integrated oil-gas heat exchanger (12) is provided at the front end of the air inlet side of the high-pressure turbine part (9) of the expander, and a second heat-charging and heat-discharging integrated oil-gas heat exchanger is provided between the high-pressure turbine part (9) of the expander and the intermediate-pressure turbine part (10) of the expander. The invention relates to a heat exchanger (13), wherein a third heat-charging and heat-releasing integrated oil-gas heat exchanger (14) is provided between the medium-pressure turbine part (10) of the expander and the low-pressure turbine part (11) of the expander; and further comprises an air storage device, wherein the air storage device comprises a high-pressure air storage chamber (3), a medium-pressure air storage chamber (2) and a low-pressure air storage chamber (1), wherein the outlet of the high-pressure air storage chamber (3) is connected to the first heat-charging and heat-releasing integrated oil-gas heat exchanger (12) through a high-pressure air storage chamber inlet / outlet valve (28); the air inlet end of the medium-pressure compressor (7) is connected to the low-pressure air storage chamber (1), and the air inlet end of the high-pressure compressor (8) is connected to the medium-pressure air storage chamber (2); The preset pressure of the low-pressure air storage chamber (1) is equal to the rated exhaust pressure of the low-pressure compressor (6) and is also equal to the rated intake pressure of the medium-pressure compressor (7); the preset pressure of the medium-pressure air storage chamber (2) is equal to the rated exhaust pressure of the medium-pressure compressor (7) and is also equal to the rated intake pressure of the high-pressure compressor (8); the preset pressure of the high-pressure air storage chamber (3) is equal to the rated exhaust pressure of the high-pressure compressor (8); The air inlet side of the low-pressure compressor (6) is provided with a low-pressure compressor air inlet valve (18), and the outlet side thereof is connected to the low-pressure turbine part (11) of the expander through the low-pressure compressor outlet valve (19) and the air inlet valve (33) of the expander low-pressure turbine; the air inlet side of the medium-pressure compressor (7) is connected to the low-pressure air storage chamber (1) through the medium-pressure compressor air inlet valve (23), and the outlet side of the medium-pressure compressor (7) is connected to the medium-pressure turbine part (11) of the expander through the medium-pressure compressor outlet valve (24) and the air inlet valve (31) of the expander medium-pressure turbine. The intermediate-pressure turbine portion (10) is provided with an expander intermediate-pressure turbine outlet valve (32) at the outlet side of the expander intermediate-pressure turbine portion (10); the air inlet side of the high-pressure compressor (8) is connected to the intermediate-pressure air storage chamber (2) via the high-pressure compressor air inlet valve (26); the outlet side of the high-pressure compressor (8) is connected to the expander high-pressure turbine portion (9) via the high-pressure compressor outlet valve (27) and the expander high-pressure turbine air inlet valve (29); and the outlet side of the expander high-pressure turbine portion (9) is connected to the expander high-pressure turbine outlet valve (30).

2. The multi-stage pressure-stabilizing cavern-type adiabatic compressed air energy storage power station system according to claim 1, characterized in that: A medium-pressure compressor bypass valve (21) is provided on the connecting pipeline between the low-pressure air storage chamber (1) and the medium-pressure air storage chamber (2), and a high-pressure compressor bypass valve (22) is provided on the connecting pipeline between the medium-pressure air storage chamber (2) and the high-pressure air storage chamber (3).

3. The multi-stage pressure-stabilizing cavern-type adiabatic compressed air energy storage power station system according to claim 1, characterized in that: The third integrated oil-gas heat exchanger (14) for heat charging and discharging is connected to the low-pressure air storage chamber (1) via the low-pressure air through the heat exchanger rear outlet valve (20); the second integrated oil-gas heat exchanger (13) for heat charging and discharging is connected to the medium-pressure air storage chamber (2) via the medium-pressure air through the heat exchanger rear outlet valve (25).

4. The multi-stage pressure-stabilizing cavern-type adiabatic compressed air energy storage power station system according to claim 1, characterized in that: It also includes a high-position normal-pressure high-temperature oil storage tank (5), a low-position normal-pressure low-temperature oil storage chamber (4) and an oil-water cooler (15), wherein the first heat-charging and releasing integrated oil-gas heat exchanger (12), the second heat-charging and releasing integrated oil-gas heat exchanger (13) and the third heat-charging and releasing integrated oil-gas heat exchanger (14) are all connected to the high-position normal-pressure high-temperature oil storage tank (5) and the oil-water cooler (15), and the oil-water cooler (15) is connected to the low-position normal-pressure low-temperature oil storage chamber (4).

5. The multi-stage pressure-stabilizing cavern-type adiabatic compressed air energy storage power station system according to claim 4, characterized in that: The first integrated oil-gas heat exchanger (12) for charging and discharging heat is connected to the high-pressure and high-temperature oil storage tank (5) through the first oil-gas heat exchanger hot oil side valve (43), and the first integrated oil-gas heat exchanger (12) for charging and discharging heat is connected to the oil-water cooler (15) through the first oil-gas heat exchanger cold oil side valve (40); the second integrated oil-gas heat exchanger (13) for charging and discharging heat is connected to the high-pressure and high-temperature oil storage tank (5) through the second oil-gas heat exchanger hot oil side valve (42), and the second integrated oil-gas heat exchanger (13) for charging and discharging heat is connected to the oil-water cooler (15) through the second oil-gas heat exchanger cold oil side valve (39); the third integrated oil-gas heat exchanger (14) for charging and discharging heat is connected to the high-pressure and high-temperature oil storage tank (5) through the third oil-gas heat exchanger hot oil side valve (41), and the third integrated oil-gas heat exchanger (14) for charging and discharging heat is connected to the oil-water cooler (15) through the third oil-gas heat exchanger cold oil side valve (38).

6. The multi-stage pressure-stabilizing cavern-type adiabatic compressed air energy storage power station system according to claim 5, characterized in that: The inlet side of the high-position normal-pressure high-temperature oil storage tank (5) is provided with a high-temperature oil storage tank inlet valve (44), which is provided on the hot oil main pipe; the outlet side thereof is provided with a hot oil pump inlet valve (45), a hot oil pump (17), a hot oil pump outlet check valve (46), and a hot oil pump outlet shut-off valve (47) in sequence; the inlet side of the low-position normal-pressure low-temperature oil storage chamber (4) is provided with a low-temperature oil storage chamber inlet valve (48), and the outlet side thereof is provided with a cold oil pump inlet valve (34), a cold oil pump (16), a cold oil pump outlet check valve (35), and a cold oil pump outlet shut-off valve (36) in sequence.

7. The multi-stage pressure-stabilizing cavern-type adiabatic compressed air energy storage power station system according to claim 5, characterized in that: Oil-water cooler bypass valves (37) are provided at both ends of the oil-water cooler (15).

8. The multi-stage pressure-stabilizing cavern-type adiabatic compressed air energy storage power station system according to claim 5, characterized in that: The three integrated oil-gas heat exchangers for charging and discharging heat are connected to the hot oil main pipe and the cold oil main pipe respectively, and a hot and cold oil connecting valve (49) is provided between the hot oil main pipe and the cold oil main pipe.

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