System and method for polyphase flow fusion compressed air energy storage power generation

Abstract

This invention relates to physical energy storage technology, aiming to provide a system and method for multiphase flow fusion-type compressed air energy storage and power generation. In this system, the power generation water body is sequentially connected to a water pump and a water storage tank, with the bottom of the water storage tank connected to a hydroelectric power generation device. At the top of the gas storage tank, an air inlet pipe connects to an air compressor, and an exhaust pipe connects to an air expander generator. A high-pressure water pump is connected to a water supply branch pipe inside the gas storage tank, with multiple atomizing nozzles on the pipe. By synchronously operating the air compressor and the high-pressure water pump, the gas storage tank can be kept in a balanced state of three-phase fluid fusion: high-temperature, high-pressure water, high-temperature, high-pressure air, and high-pressure steam. The water storage tank and the gas storage tank are connected, enabling pressure balance between the different media. This invention adopts the principle of adiabatic compression and non-isothermal expansion, which, compared to the near-isothermal process principle of traditional technologies, can further improve system energy efficiency, minimize energy loss, and enhance the overall efficiency of the energy storage system.

Description

Technical Field

[0001] This invention relates to the field of physical energy storage technology, specifically to a system and method for multiphase flow integrated compressed air energy storage and power generation. Background Technology

[0002] Against the backdrop of a global energy structure transition towards green and low-carbon development, the grid-connected scale of intermittent renewable energy sources (such as wind and solar power) continues to expand, posing a severe challenge to the grid's regulation capacity. Energy storage technology, especially large-scale physical energy storage, is a key means to solve these problems, effectively reducing wind and solar curtailment and making rational use of peak and off-peak electricity. Currently, pumped hydro storage and compressed air storage are the two most mature physical energy storage technologies with the largest installed capacity.

[0003] In recent years, researchers have proposed a hybrid compressed air energy storage concept that combines compressed air energy storage with pumped hydro storage. For example, Chinese patent document CN116792173A proposes a "multi-unit near-constant pressure pumped hydro compressed air hybrid energy storage system and its operation method." This system maintains stable compressed air pressure through water pressure while utilizing water to absorb some of the heat released by the compressed air, thereby improving the energy efficiency of a single unit. Further research has proposed using high-temperature water to provide the heat required for compressed air expansion during the turbine power generation stage. These research results have, to some extent, improved the overall efficiency and application flexibility of physical energy storage.

[0004] However, current single compressed air energy storage technology still has significant shortcomings, including low overall efficiency, demanding geographical conditions, inefficient utilization of compression heat, generally low investment economics, and limitations in large-scale promotion. For example, the technical solution in Chinese patent document CN116792173A has the following defects: First, this solution prioritizes using compressed air expansion to generate electricity, and then uses residual pressure water for hydroelectric power generation. However, the efficiency of compressed air expansion power generation is generally 60%~75%, while the minimum efficiency of conventional hydroelectric power generation can reach over 90% (large units can reach over 96%), making the power generation efficiency relatively low; Second, commercial application cases show that the system energy efficiency of compressed air energy storage is around 60~70%, while the system energy efficiency of pumped hydro storage (energy storage) is 70~82%; Third, compressed air maintains a near-isothermal process, which cannot efficiently utilize its compression heat, and the large amount of wasted compression heat directly lowers the system energy efficiency of the energy storage system. Furthermore, the system employs a relatively slow charge and discharge rate, resulting in relatively low overall power density and energy density. Fourthly, the energy density, energy storage capacity, and total energy storage of this energy storage solution are generally low. In order to store compressed air, a large number of pressure vessels are required. In practical application scenarios, due to the need for ground-based deployment, there are equipment safety risks and expensive land use costs, making it difficult to achieve large-capacity energy storage and large-scale commercial application.

[0005] This invention aims to propose a novel solution to address the aforementioned problems. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a system and method for multiphase flow integrated compressed air energy storage and power generation.

[0007] To solve the technical problem, the solution of the present invention is:

[0008] A multiphase flow integrated compressed air energy storage and power generation system is provided. The system includes a power generation water body and an energy storage and power generation device, the latter including a water storage tank and an air storage tank.

[0009] The power generation water body is connected to the water pump and the water storage tank in sequence through the second water inlet pipe, and the bottom of the water storage tank is connected to the hydroelectric power generation equipment and the power generation water body in sequence through the drain pipe;

[0010] The gas storage tank is equipped with an air inlet pipe, an air outlet pipe, and an emergency exhaust pipe at the top. An air compressor is installed on the air inlet pipe, and an air expander generator is installed on the exhaust pipe. The emergency exhaust pipe is connected to the atmosphere. The main water supply pipe is connected to the gas storage tank via a high-pressure water pump, and the end of the main water supply pipe is connected to multiple parallel water supply branch pipes. Several atomizing nozzles are arranged on each water supply branch pipe. By synchronously operating the air compressor and the high-pressure water pump, the gas storage tank can be kept in a balanced state of three-phase fluid fusion of high-temperature and high-pressure water, high-temperature and high-pressure air, and high-pressure steam at a temperature of 150℃~300℃ and a pressure of 2.5~3.5MPa. The water storage tank and the gas storage tank are connected by a connecting air pipe to achieve pressure balance between the different media.

[0011] As a preferred embodiment of the present invention, the water body for power generation is a reservoir, an artificial reservoir, or an artificially modified river, which has sufficient water volume to stably supply water for power generation.

[0012] As a preferred embodiment of the present invention, both the water storage tank and the gas storage tank are long horizontal tanks or long tubular containers buried underground, and the water storage tank is located above the gas storage tank to shield the latter.

[0013] As a preferred embodiment of the present invention, the position of the power generation water body is higher than that of the water storage tank, and a first water inlet pipe is provided connecting the power generation water body and the bottom of the water storage tank, and a first regulating valve is provided on the water pipe; the bottom of the water storage tank is connected to the power generation water body through an emergency drain pipe, and a drain venting valve is provided on the water pipe.

[0014] As a preferred embodiment of the present invention, a second regulating valve is provided on the second water inlet pipe; a third regulating valve is provided on the air inlet pipe; a fourth regulating valve is provided on the connecting air pipe; a fifth regulating valve is provided on the drain pipe; a sixth regulating valve is provided on the exhaust pipe; a seventh regulating valve is provided on the main water supply pipe; and an exhaust venting valve is provided on the emergency exhaust pipe; and a filter screen is provided at the inlet of the water inlet pipe.

[0015] As a preferred embodiment of the present invention, a level gauge for monitoring the water storage progress is provided on the water storage tank, and a temperature sensor and a pressure sensor are provided inside the water storage tank and the gas storage tank; the level gauge, temperature sensor and pressure sensor are all connected to a remote host computer through signal lines.

[0016] As a preferred embodiment of the present invention, the hydroelectric power generation equipment is a water turbine generator, or a combination of a hydraulic turbine expander and a water turbine generator.

[0017] As a preferred embodiment of the present invention, there are multiple water storage tanks and multiple gas storage tanks, with each water storage tank arranged in parallel or series, and each gas storage tank arranged in parallel or series; each water storage tank and each gas storage tank uses a tank body of the same specification, and the total volume ratio of all water storage tanks to all gas storage tanks is 3:1~2.

[0018] As a preferred embodiment of the present invention, the multiple parallel water supply branches in the gas storage tank are divided into upper and lower sides and are arranged horizontally along the axial direction of the tank body; the atomizing nozzles of the upper water supply branch and the lower water supply branch are arranged opposite each other and facing the center of the tank body.

[0019] This invention further provides a method for realizing multiphase flow fusion-type compressed air energy storage and power generation using the aforementioned system, comprising two stages: system energy storage and energy release and power generation, wherein:

[0020] (1) The system energy storage stage includes:

[0021] After the water storage tank is filled with water through the first water inlet pipe and / or the second water inlet pipe, the water pump is used to pressurize the tank and then the valves on each pipe of the water storage tank are closed.

[0022] Start the air compressor to deliver compressed air into the gas storage tank, and simultaneously start the high-pressure water pump to scatter high-pressure water mist into the tank through atomizing nozzles until the pressure inside the tank reaches the set value.

[0023] By using a connecting pipe to achieve pressure transfer between the medium in the gas storage tank and the water storage tank, the pressure inside the gas storage tank will decrease; the air compressor and high-pressure water pump continue to run until the pressure inside the gas storage tank returns to the set value; at this time, the water storage tank and the gas storage tank maintain pressure balance, and the gas storage tank is in a state of equilibrium where the three-phase fluids of high-temperature and high-pressure water, high-temperature and high-pressure air and high-pressure steam are fused.

[0024] (2) The energy release and power generation stage includes:

[0025] The drain pipe connected to the water storage tank is used to generate electricity directly using hydroelectric power generation equipment, and the discharged water flows back to the power generation water storage body;

[0026] As the water storage tank gradually decreases, the gas pressure in the gas storage tank also decreases accordingly. During this process, the high-temperature hot water in the tank continuously flashes to form steam, which can maintain the pressure in the water storage tank to continuously drain the water. When the flashing process in the gas storage tank weakens and the pressure continues to drop, an air compressor is used to replenish the gas appropriately to maintain the three-phase fusion state. In this way, the hydroelectric power generation equipment can maintain an appropriate power generation efficiency until the water in the water storage tank is completely drained.

[0027] The water storage tank and the gas storage tank are connected to the exhaust pipe, and the remaining high-temperature and low-pressure gas is sent into the air expansion generator for secondary power generation.

[0028] As a preferred embodiment of the present invention, the outlet gauge pressure of the atmospheric pressure water pump is 0.2~0.5 MPa; the outlet pressure of the high pressure water pump is >3.5 MPa; the outlet temperature of the air compressor is 200~350℃ and the pressure is 2.5~3.5 MPa; when the gas storage tank is in a three-phase fusion equilibrium state, the temperature inside the tank is 150℃~300℃ and the pressure is 2.5~3.5 MPa.

[0029] As a preferred embodiment of the present invention, a hydro-turbine generator is used for direct power generation during the energy release and power generation stage; or, a combination of a hydraulic turbine expander and a hydro-turbine generator is used to achieve secondary power generation; the secondary power generation refers to: firstly, high-pressure water (>2.5MPa) in the water storage tank is used to drive the hydraulic turbine expander for the first stage of power generation, and after the pressure at the equipment outlet drops to 0.4~1MPa, medium-pressure water is used to drive the hydro-turbine generator for the second stage of power generation; wherein, the hydraulic turbine expander and the hydro-turbine generator are coaxial units or independent units.

[0030] Description of the invention principle:

[0031] The adiabatic compression and non-isothermal expansion adopted in this invention specifically refer to the following: during the energy storage stage, the air compressor adopts a near-adiabatic compression process (non-isothermal compression process), without setting up an interstage cooler, and the system has no significant heat exchange with the outside world (adiabatic compression), thus retaining the heat of compression; during the energy release and power generation process, the temperature of the compressed air in the gas storage tank will change, and it is not necessary to demand a near-isothermal process. The pressure is maintained and the energy conversion efficiency is improved through the phase change of water and water vapor and heat recovery.

[0032] Its implementation principle is as follows:

[0033] (1) Adiabatic compression: This is achieved through a combination of an air compressor, a high-pressure water pump, and a high-pressure water nozzle. During the energy storage stage, the air compressor compresses air to a high temperature and high pressure state and sends it into the gas storage tank. At the same time, the high-pressure water nozzle sprays high-pressure water into the gas storage tank. The water partially evaporates at high temperature to form steam, which mixes with the compressed air to form a three-phase fused fluid of high-temperature and high-pressure water, air, and steam. The heat of compression is absorbed by the water and stored in the steam, thus realizing the utilization of the heat of compression.

[0034] (2) Non-isothermal expansion: This is achieved through the coordinated operation of a water storage tank and a gas storage tank. During the energy release and power generation stage, the high-pressure water in the water storage tank drives the hydro-generator to generate electricity. At the same time, the pressure inside the gas storage tank decreases, and the high-temperature hot water at the bottom flashes out steam to automatically replenish the pressure. However, the temperature of the two phases of compressed air and high-temperature water vapor will also decrease appropriately as the pressure decreases. When the pressure is insufficient, the air compressor replenishes the air to maintain the power generation efficiency. Finally, the remaining compressed air generates electricity again through the air expander generator. Although the temperature changes during the expansion process, it can be compensated by the heat of the internal steam, thereby avoiding energy loss.

[0035] (3) Heat flow and phase change in the fusion of three phases:

[0036] During the energy storage phase, high-temperature compressed air (150℃~300℃, pressure 2.5~3.5MPa) in the gas storage tank is mixed with high-pressure water (atomized through a high-pressure water nozzle). The water absorbs the heat of compression and partially transforms into steam, forming a steady-state three-phase fused fluid. This fused fluid has a high energy density, and the heat is in dynamic equilibrium among the water, air, and steam.

[0037] During the power generation phase, as water is discharged, the pressure in the gas storage tank decreases, and the high-temperature water flashes into steam, releasing the stored heat and maintaining system pressure. Simultaneously, as the compressed air expands, the heat from the steam provides a supplement, reducing efficiency losses caused by temperature drops. Throughout the process, heat circulates between the media, and phase changes are actively utilized for energy regulation.

[0038] (4) Energy efficiency advantages compared to near-isothermal processes:

[0039] Existing technologies (such as CN116792173A) employ near-isothermal processes, requiring external heat exchange to maintain a constant temperature. However, compression heat is easily lost, and adding supplementary heating equipment further increases system complexity, resulting in low overall efficiency. This invention retains compression heat through adiabatic compression and utilizes the internal heat capacity and phase change of water through non-isothermal expansion, eliminating the need for external heating and reducing energy loss. Furthermore, based on water's enormous heat capacity and latent heat of phase change, efficient heat storage and release are achieved, further optimizing energy utilization.

[0040] This invention breaks through the traditional thinking of ordinary technicians in compressed air energy storage technology, abandoning the conventional approach of simply pursuing optimized solutions for isothermal or adiabatic processes. It proposes an innovative approach that combines adiabatic compression with non-isothermal expansion, and achieves the recycling of heat within the system through a three-phase fusion design. By using an air storage tank in conjunction with an air compressor, multiphase flow can operate under steady-state conditions. Using underground storage tanks (or storage pipes) instead of conventional large vertical storage tanks overcomes geographical limitations while improving safety and flexibility.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. This invention adopts the principle of adiabatic compression and non-isothermal expansion, which can further improve the system energy efficiency compared with the near-isothermal process principle of traditional technology. By utilizing the auxiliary energy storage of high-pressure water, the huge heat capacity of high-temperature water and the efficient utilization of compression heat, energy loss is minimized, thereby improving the overall efficiency of the energy storage system.

[0043] 2. In this invention, individual water storage tanks and individual gas storage tanks use the same specifications, facilitating standardized production. However, the total volume ratio of all water storage tanks to all gas storage tanks is 3:1~2, making the total volume of the water storage tanks significantly larger than that of the gas storage tanks, thus significantly improving the system's energy density and power density. Compared to traditional solutions that extensively use compressed gas containers, this invention maximizes energy storage power and total energy storage while further enhancing safety.

[0044] 3. The compressed air energy storage system of the present invention does not require a specific underground chamber. By burying high-pressure pipes such as water storage tanks and gas storage tanks underground, the total volume of the required pressure vessels is greatly reduced. This greatly breaks through the geographical limitations of traditional compressed air energy storage, thereby enabling flexible construction based on local conditions.

[0045] 4. This invention is a novel compressed air energy storage technology with high energy efficiency, high safety, and high stability. In suburban areas, it can utilize existing reservoirs, ponds, and modified river sections as natural water bodies; in urban areas, it can cleverly utilize existing infrastructure (such as landscape ponds), seamlessly integrating energy storage technology with the ecological landscape, thus facilitating large-scale promotion in practical applications. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the overall structure of the multiphase flow fusion type compressed air energy storage system of the present invention.

[0047] The attached diagram is labeled as follows: 1. Landscape pool; 2. Filter screen; 3. Water pump; 401. First regulating valve; 402. Second regulating valve; 403. Third regulating valve; 404. Fourth regulating valve; 405. Fifth regulating valve; 406. Sixth regulating valve; 407. Seventh regulating valve; 501. Drainage vent valve; 502. Exhaust vent valve; 6. Water storage tank; 7. Air storage tank; 8. Air compressor; 9. Water turbine generator; 10. Air expander generator; 11. High-pressure water pump; 12. Atomizing nozzle; 20. Air inlet pipe; 21. Exhaust pipe; 22. Emergency exhaust pipe; 23. Main water supply pipe; 24. First water inlet pipe; 25. Second water inlet pipe; 26. Main water inlet pipe; 27. Drainage pipe; 28. Emergency drainage pipe; 29. ​​Connecting air pipe. Detailed Implementation

[0048] To better understand the purpose, structure, and function of this invention, the invention will be further described in detail below with reference to the accompanying drawings. The serial numbers assigned to components in this application, such as "first," "second," etc., are merely for distinguishing the described objects and do not have any sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages). In the description of this application, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0049] Part 1: Structural Layout Description of the Device

[0050] The specific structure of the multiphase flow fusion type compressed air energy storage system in this invention is as follows: Figure 1 As shown, the system includes a water body for power generation and an energy storage and power generation device. In this example, a landscape pond 1 built on the ground surface is used as the water body for power generation, and its design capacity is determined according to the actual terrain and operational scale. The energy storage and power generation device includes a water storage tank 6 and a gas storage tank 7. These are the core energy storage containers, but the pressure requirements are not high. A traditional long horizontal tank (or a long tubular container) made of carbon steel can be selected and supplemented with appropriate insulation. The whole assembly is then installed in the foundation pit under the landscape pond 1 to save surface space. To improve safety, the water storage tank 6 is installed above the gas storage tank 7 to act as a barrier and shield in the event of an overpressure explosion of the latter.

[0051] Based on the capacity of the water storage tanks and the energy storage and power generation requirements, the system can be modified to use a combination of multiple water storage tanks 6 and multiple gas storage tanks 7. The water storage tanks 6 are arranged in parallel or series, and the gas storage tanks 7 are also arranged in parallel or series. The connection between the water storage tanks 6 and the gas storage tanks 7 is designed according to actual control requirements. Individual water storage tanks 6 and individual gas storage tanks 7 can use tanks of uniform specifications to facilitate standardized production. The total volume ratio of all water storage tanks 6 to all gas storage tanks 7 is 3:1~2. The purpose of this design is to improve the system's energy density and power density. This invention, through a storage medium ratio of "water as the main component and gas as a supplement," stores the majority of energy in high-pressure water and releases it through efficient hydroelectric power generation equipment; while the gas storage tanks 6 and the three-phase fused fluid within them mainly serve to maintain the system's pressure platform.

[0052] The energy storage power generation device also includes a water pump 3, an air compressor 8, a hydro-generator 9, an air expander generator 10, a high-pressure water pump 11, related connecting pipelines and control valves, and a control system composed of necessary instruments (such as temperature sensors, pressure sensors, level gauges, etc. installed in each tank) and a host computer. Based on common industry knowledge, the host computer needs to be connected to various instruments, control valves, and operating equipment (such as water pumps, compressors, hydroelectric power generation equipment, generators, etc.) via signal lines to achieve the control objectives of system operation. Since the selection, installation, and use of these instruments, control valves, and operating equipment are all conventional technologies well-versed by those skilled in the art, this invention will not describe them in detail.

[0053] A filter screen 2 is installed at the outlet at the bottom of the landscape pond 1 to filter impurities. The first inlet pipe 24 and the second inlet pipe 25 are connected in parallel, with their inlets located below the filter screen 2. A first regulating valve 401 is installed on the first inlet pipe 24, and a water pump 3 and a second regulating valve 402 are installed on the second inlet pipe 25. The ends of the two pipes are merged into a main inlet pipe 26, which is finally connected to the bottom inlet of the water storage tank 6. The bottom outlet of the water storage tank 6 is connected to a drain pipe 27, on which a fifth regulating valve 405 and a water turbine generator 9 are installed in sequence. An emergency drain pipe 28 is also connected to the drain pipe 27, with the connection point located before the fifth regulating valve 405. A drain vent valve 501 is installed on the emergency drain pipe 28. The ends of both the drain pipe 27 and the emergency drain pipe 28 lead into the landscape pond 1.

[0054] An air inlet and an exhaust outlet are located at the top of the gas storage tank 7, and are connected to an air inlet pipe 20 and an exhaust pipe 21, respectively. An air compressor 8 and a third regulating valve 403 are installed on the air inlet pipe 21, and a sixth regulating valve 406 and an air expander generator 10 are installed on the exhaust pipe 21. An emergency exhaust pipe 28 is connected before the sixth regulating valve 406, and a drain vent valve 502 is installed on the emergency exhaust pipe 28. The air inlet end of the air inlet pipe 20, the air outlet of the air expander generator 10, and the emergency exhaust pipe 28 are all open to the atmosphere. A high-pressure water pump 11 and a seventh regulating valve 407 are sequentially installed on the main water supply pipe 23, the end of which extends into the inner cavity of the gas storage tank 7 and is connected to two parallel water supply branch pipes.

[0055] Two water supply branches are fixedly installed on the upper and lower sides of the inner cavity of the gas storage tank 7, respectively, and are arranged horizontally along the axial direction of the tank. Multiple atomizing nozzles 12 are evenly arranged on each of the two water supply branches, with the nozzles on both branches facing each other towards the center of the tank. The atomizing nozzles 12 are used to spray high-pressure water mist into the internal space of the gas storage tank 7, directly mixing with the high-temperature compressed air introduced by the air compressor 8, promoting further evaporation of water particles to form high-temperature, high-pressure steam. The relative arrangement of the nozzles allows the sprayed water mist to form turbulence with the compressed air inside the tank, prolonging the residence time of the water mist in the tank space and improving heat exchange and mixing efficiency. After sufficient heat exchange, the high-temperature steam partially liquefies into water under high pressure and accumulates at the bottom of the tank. This water will be used for flash evaporation to maintain the system pressure during subsequent energy release. If all nozzles are concentrated on the upper or lower side, the temperature rise of the water accumulated at the bottom of the tank may be insufficient, affecting the uniformity of the three-phase fluid fusion.

[0056] The tops of the water storage tank 6 and the gas storage tank 7 are connected via a connecting pipe 29, which is equipped with a fourth regulating valve 404. By synchronously operating the air compressor 8 and the high-pressure water pump 11, the gas storage tank 7 can be kept in a balanced state of three-phase fusion, consisting of high-temperature and high-pressure water (150℃~300℃) and high-pressure air (2.5~3.5MPa). The connecting pipe 29 also enables pressure balance between the different media in the water storage tank 6 and the gas storage tank 7.

[0057] Part Two: System Operation Instructions

[0058] This invention provides a method for realizing multiphase flow integrated compressed air energy storage and power generation, comprising two stages: system energy storage and energy release and power generation, wherein:

[0059] 1. Energy storage stage:

[0060] Open the first regulating valve 401 and the second regulating valve 402, and close the other valves. The water in the landscape pool 1 is first filtered for impurities by the filter screen 2, and the purified water flows into the first inlet pipe 24 and into the water storage tank 6 by its own gravity potential energy. At the same time, the water pump 3 on the second inlet pipe is turned on to continuously pump water into the water storage tank 6. When the water storage tank is full, the water pressure in the water storage tank can be maintained at 0.05~0.1 MPa (g, gauge pressure).

[0061] Close the first regulating valve 401 and the second regulating valve 402. Then open the third regulating valve 403 and the seventh regulating valve 407, and start the air compressor 8 to deliver high-pressure, high-temperature compressed air (pressure range between 2.5 and 3.5 MPa, temperature range between 200 and 350°C) into the air storage tank 7. At the same time, use the high-pressure water pump 11 (outlet pressure > 3.5 MPa) to simultaneously spray a small amount of mist water into the inner cavity of the air storage tank 7 through the atomizing nozzle 12 until the pressure inside the air storage tank 7 reaches the set value (pressure range between 2.5 and 3.5 MPa). At this time, the inside of the air storage tank 7 is in a three-phase fluid fusion state of high-temperature, high-pressure water, high-temperature, high-pressure air, and high-pressure steam. Next, the fourth regulating valve 404 is opened to connect the water storage tank 6 and the gas storage tank 7, causing the water in the water storage tank 6 to rapidly increase in pressure. At this time, the pressure inside the gas storage tank 7 will drop slightly. The air compressor 8 and the high-pressure water pump 11 continue to run until the pressure inside the gas storage tank 7 returns to the set value, and the tank is in a balanced state of three-phase fluid fusion of high-temperature and high-pressure water, high-temperature and high-pressure air, and high-pressure steam (tank pressure 2.5~3.5MPa, temperature 150℃~300℃). The water storage tank 6 and the gas storage tank 7 maintain pressure balance, and finally the energy storage is completed.

[0062] 2. Energy release and power generation stage:

[0063] (1) Stage of directly utilizing water pressure to release energy:

[0064] Keep the fourth regulating valve 404 open, close the other valves, and open the fifth regulating valve 405. At this time, the high-pressure water stored in the water storage tank 6 flows into the drain pipe 27 and directly generates electricity using the hydroelectric power generation equipment. The water discharged after power generation flows directly back into the landscape pool 1.

[0065] Two power generation methods are available at this stage. One is direct power generation, which uses the high-pressure water inside the water storage tank 6 to drive the turbine generator 9. In this case, a high-head, large-capacity variable-speed turbine generator set should be prioritized. The other method is two-stage power generation, which uses a combination of a hydraulic turbine expander and a turbine generator. The specific process is as follows: the first stage uses high-pressure water to drive the hydraulic turbine expander to generate electricity. After the first stage, the outlet water becomes medium-pressure water, which is then used to drive the turbine generator 9 for the second stage of power generation. The hydraulic turbine expander and turbine generator 9 can either form a coaxial unit or operate as independent units. Using the above power generation methods, although the power generation will decrease linearly as the pressure of the high-pressure water inside the water storage tank 6 gradually decreases, the overall power generation efficiency of the system can still be maintained at a high level.

[0066] (2) Maintaining pressure using flash evaporation:

[0067] As the water level in the water storage tank 6 gradually decreases, the air pressure in the gas storage tank 7 will also decrease accordingly. When the pressure in the gas storage tank 7 drops, the high-temperature hot water at its bottom will flash steam, which can maintain the drainage pressure in the water storage tank 6 for a relatively long time and prevent the water pressure from dropping rapidly. When the air pressure in the gas storage tank 7 continues to drop to a level that cannot meet the efficient drainage requirements of the water storage tank 6, the third regulating valve 403 is opened and the air compressor 8 is started to replenish the air appropriately, ensuring that the hydro-generator 9 can maintain a suitable power generation efficiency until the water inside the water storage tank 6 is completely emptied.

[0068] (3) Power generation using residual gas pressure:

[0069] After all the water in the water storage tank 6 is drained, the compressed air pressure in the air storage tank 7 can still be maintained at about 0.3 MPa. This pressure can be used to drive the air expander generator 10 to generate electricity. At this time, the fifth regulating valve 405 is closed and the sixth regulating valve 406 is opened, allowing the excess high-temperature, low-pressure compressed air in the water storage tank 6 and the air storage tank 7 to flow into the exhaust pipe 21 and into the air expander generator 10 equipped with a drying device for secondary power generation.

[0070] In this embodiment, the power generation efficiency of the hydro-generator 9 does not need to be kept constant. The power generation efficiency is high in the initial stage of power generation; even if the efficiency decreases in the later stage, excessive compressed air is not required to maintain the overall energy efficiency of the system.

[0071] If a malfunction occurs during operation and causes the pressure of the water storage tank 6 or the gas storage tank 7 to exceed the limit, the drain vent valve 501 or the exhaust vent valve 502 can be opened to release the pressure from the emergency drain pipe 28 or the emergency exhaust pipe 22 to ensure equipment safety.

[0072] Part Three: Specific Implementation Examples

[0073] Two compressed air energy storage systems, the present invention (multiphase flow fusion type) and a comparative example (CN116792173A, near-isothermal, near-constant pressure type), were built on a simulation platform (MATLAB / Simulink) at a scale of 1:1. Simulation was used to quantify and compare the cycle efficiency of the two systems, verifying the energy efficiency improvement effect of the present invention through "adiabatic compression" and "non-isothermal expansion" utilizing the heat of compression.

[0074] I. Model Building and Key Parameter Setting

[0075] Set up a pilot-scale system with a total energy storage capacity of 1MWh.

[0076] 1. Common parameters (consistent in both schemes):

[0077] Energy storage capacity: 1MWh; Initial pressure (before energy storage): 0.1 MPa (a, absolute pressure); Maximum operating pressure: 2 MPa (g); Ambient temperature: 20°C; Compressor isentropic efficiency: 75%; Expander / turbine isentropic efficiency: 78%; Pump efficiency: 78%; Water temperature of the power generation and storage water body: 20°C (constant temperature).

[0078] 2. Key settings of the comparative model (CN116792173A): Pursuing near-isothermal processes and emphasizing real-time heat exchange.

[0079] 3. Key settings of the model of this invention (multiphase flow fusion type): adiabatic compression to store heat, using the heat capacity of water to store heat, and non-isothermal expansion to recover heat.

[0080] II. Simulation Calculation Results

[0081] 1. Round-Trip Efficiency (RTE) is a core indicator for measuring the performance of energy storage systems. The calculation formula is as follows:

[0082] RTE = (Total electrical energy output during the discharge phase) / (Total electrical energy input during the charging phase) × 100%.

[0083] 2. Cyclic efficiency calculation of the comparative example (CN116792173A):

[0084] (1) Energy storage stage (power consumption calculation)

[0085] The system needs to store 1 MWh of energy in a storage tank.

[0086] In near-isothermal compression, the water pump and turbine perform work. It is the primary energy input.

[0087] Assuming the efficiency of the water pump and turbine is 78%, the actual electrical energy consumed is: Total energy storage power consumption = 1MWh / 0.78 = 1.282MWh.

[0088] In addition, equipment such as water pumps and turbines will also consume a small amount of electricity, let's say 0.05 MWh.

[0089] Therefore, the total power consumption during the energy storage phase =1.282+0.05 ≈1.332MWh.

[0090] (2) Energy release and power generation stage (power generation calculation)

[0091] The energy stored in the tank is 1 MWh of room temperature high-pressure air (potential energy).

[0092] The turbine efficiency is 78%, therefore the power generation is:

[0093] Electricity generated = Stored energy 1MWh × 0.78 = 0.78MWh

[0094] Therefore, the total power generation during the energy release phase =0.78MWh.

[0095] (3) Calculation of cycle efficiency

[0096] = (0.78 / 1.332) ×100%=58.56%

[0097] 3. Calculation of the cycle efficiency of the present invention:

[0098] The core of this invention is adiabatic compression and internal heat storage, following the principle of "using one's own heat".

[0099] (1) Energy storage stage (power consumption calculation)

[0100] It also requires storing 1 MWh of energy.

[0101] With an adiabatic compression efficiency of 75%, the compressor consumes 1.333 MWh of electricity.

[0102] The power consumption of a small high-pressure water pump is very small, let's say 0.02MWh.

[0103] Therefore, the total power consumption during the energy storage phase =1.333+0.02≈1.353MWh.

[0104] (2) Energy release and power generation stage (power generation calculation)

[0105] At this point, the system has a total of 1.333 MWh of energy available for use (1 MWh of mechanical energy + 0.333 MWh of thermal energy).

[0106] The turbine and expander generate electricity separately (with the same efficiency: 78%).

[0107] Hydroelectric power generation: utilizes the potential energy and some thermal energy of water; air expansion generator power generation: utilizes the potential energy and stored thermal energy of air.

[0108] Therefore, the total power generation during the energy release phase =1.333×0.78=1.04MWh.

[0109] (3) Calculation of cycle efficiency

[0110] = (1.04 / 1.353)×100% =76.85%

[0111] In the comparative example (CN116792173A), the technical solution absorbs the heat of compression of compressed air with water and releases the heat required for the expansion of compressed air to achieve "near isothermal" energy storage and release. Its "near constant pressure" operation goal is to enable the turbine and pump to operate near the rated pressure with the highest efficiency.

[0112] Compared to this approach, the present invention employs "adiabatic compression," which allows for temperature variations and recovers high-quality (high-temperature) heat energy, resulting in higher efficiency in heat-to-work conversion. Secondly, the present invention significantly mitigates pressure fluctuations at the turbine inlet through system design, enabling the turbine to operate at a more stable pressure closer to its rated operating conditions. Therefore, the present invention achieves a dual improvement in both the quality and quantity of energy through "adiabatic compression" and "system optimization."

[0113] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A system of polyphase flow fusion type compressed air energy storage power generation, characterized in that, The system includes a water body for power generation and an energy storage and power generation device, the latter including a water storage tank and a gas storage tank; The water body for power generation is positioned higher than the water storage tank, and a first inlet pipe is provided connecting the water body for power generation to the bottom of the water storage tank. A first regulating valve is provided on the water pipe. The bottom of the water storage tank is connected to the water body for power generation through an emergency drain pipe, and a drain vent valve is provided on the water pipe. The power generation water body is connected to the water pump and the water storage tank in sequence through the second water inlet pipe, and the bottom of the water storage tank is connected to the hydroelectric power generation equipment and the power generation water body in sequence through the drain pipe; The gas storage tank is equipped with an air inlet pipe, an air outlet pipe, and an emergency exhaust pipe at the top. An air compressor is installed on the air inlet pipe, and an air expander generator is installed on the exhaust pipe. The emergency exhaust pipe is connected to the atmosphere. The main water supply pipe is connected to the gas storage tank via a high-pressure water pump, and the end of the main water supply pipe is connected to multiple parallel water supply branch pipes. Several atomizing nozzles are arranged on each water supply branch pipe. By synchronously operating the air compressor and the high-pressure water pump, the gas storage tank can be kept in a balanced state of three-phase fluid fusion of high-temperature and high-pressure water, high-temperature and high-pressure air, and high-pressure steam at a temperature of 150℃~300℃ and a pressure of 2.5~3.5Mpa. The water storage tank and the gas storage tank are connected by a connecting air pipe to achieve pressure balance between the different media.

2. The system of claim 1, wherein, The water body for power generation is a reservoir, an artificial reservoir, or an artificially modified river, with sufficient water volume to stably supply water for power generation; the hydroelectric power generation equipment is a water turbine generator, or a combination of a hydraulic turbine expander and a water turbine generator.

3. The system of claim 1, wherein, Both the water storage tank and the gas storage tank are long, horizontal tanks or long tubular containers buried underground, with the water storage tank located above the gas storage tank to shield it. A level gauge is installed on the water storage tank to monitor the water storage progress, and temperature and pressure sensors are installed inside both the water and gas storage tanks. The level gauge, temperature and pressure sensors are all connected to a remote host computer via signal lines.

4. The system according to claim 1, characterized in that, A second regulating valve is installed on the second water inlet pipe; a third regulating valve is installed on the air inlet pipe; a fourth regulating valve is installed on the connecting air pipe; a fifth regulating valve is installed on the drain pipe; a sixth regulating valve is installed on the exhaust pipe; a seventh regulating valve is installed on the main water supply pipe; and an exhaust vent valve is installed on the emergency exhaust pipe; a filter screen is installed at the inlet of the water inlet pipe.

5. The system according to claim 1, characterized in that, There are multiple water storage tanks and multiple gas storage tanks. The water storage tanks are arranged in parallel or series, and the gas storage tanks are arranged in parallel or series. All water storage tanks and gas storage tanks use tanks of the same specifications. The total volume ratio of all water storage tanks to all gas storage tanks is 3:1~2.

6. The system according to claim 1, characterized in that, The gas storage tank has multiple parallel water supply branches on the upper and lower sides, which are arranged horizontally along the axial direction of the tank. The atomizing nozzles of the upper and lower water supply branches are set opposite each other and face the center of the tank.

7. A method for realizing multiphase flow integrated compressed air energy storage and power generation using the system described in any one of claims 1 to 6, characterized in that, include: (1) System energy storage stage: After the water storage tank is filled with water, the pressure is increased by a water pump; Compressed air is supplied into the gas storage tank, and high-pressure water mist is simultaneously scattered into the tank until the pressure inside the tank reaches the set value. The medium connecting the gas storage tank and the water storage tank enables pressure transmission, causing the pressure inside the tank to drop. The air compressor and high-pressure water pump continue to run until the pressure inside the tank returns to the set value. At this time, the water storage tank and the gas storage tank maintain pressure balance, and the gas storage tank is in a state of equilibrium where high-temperature and high-pressure water, high-temperature and high-pressure air, and high-pressure steam are three-phase fluids. (2) Energy release and power generation stage: The drain pipe connected to the water storage tank is used to generate electricity directly using hydroelectric power generation equipment, and the discharged water flows back to the power generation water storage body; When the pressure inside the gas storage tank decreases as the water storage tank decreases, the high-temperature hot water inside the tank continues to flash and generate steam to maintain the pressure inside the water storage tank for continuous drainage. When the flashing weakens and the pressure continues to drop, an air compressor is used to replenish the air to maintain the three-phase fusion state, so that the hydroelectric power generation equipment can maintain appropriate power generation efficiency until the water in the water storage tank is completely emptied. Connect the water storage tank to the gas storage tank, and send the remaining high-temperature, low-pressure gas into the air expansion generator for secondary power generation.

8. The method according to claim 7, characterized in that, The outlet gauge pressure of the atmospheric pressure water pump is 0.2~0.5 MPa; the outlet pressure of the high pressure water pump is >3.5 MPa; the outlet temperature of the air compressor is 200~350℃ and the pressure is 2.5~3.5 MPa; when the gas storage tank is in a three-phase fusion equilibrium state, the temperature inside the tank is 150℃~300℃ and the pressure is 2.5~3.5 MPa.

9. The method according to claim 7, characterized in that, In the energy release and power generation stage, a hydro turbine generator is used for direct power generation; or, a combination of a hydraulic turbine expander and a hydro turbine generator is used to achieve secondary power generation. The secondary power generation refers to: firstly, using high-pressure water (>2.5 MPa) in the water storage tank to drive the hydraulic turbine expander for the first stage of power generation; after the pressure drops to 0.4~1 MPa at the equipment outlet, using medium-pressure water to drive the turbine generator for the second stage of power generation; wherein, the hydraulic turbine expander and the turbine generator are coaxial units or independent units.

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