A compressed air energy storage power generation system and method based on ejection flash

Abstract

The application belongs to the technical field of energy storage power generation, and particularly relates to a compressed air energy storage power generation system and method based on jet flash. The compressed air energy storage power generation system based on jet flash comprises a compression subsystem, an energy storage subsystem and an expansion energy release subsystem; the compression subsystem is composed of two or more compressor groups in series; the energy storage subsystem comprises a storage tank, a first valve, a second valve, a storage tank working medium pump, one or more heat storage heat exchangers, a circulating liquid inlet pipe and a circulating liquid outlet pipe; the compression subsystem compresses air by using surplus electricity to obtain high-temperature and high-pressure air; the energy storage subsystem converts the energy in the high-temperature and high-pressure air into the internal energy of high-temperature and high-pressure liquid-phase working medium, and stores the high-temperature and high-pressure liquid-phase working medium for later use; when the electricity demand is high, the expansion energy release subsystem expands the high-temperature and high-pressure liquid-phase working medium to generate power, thereby relieving the tight electricity demand. The application can more efficiently regulate and control the electricity supply in different electricity consumption periods.

Description

Technical Field

[0001] This invention belongs to the field of energy storage and power generation technology, and particularly relates to a compressed air energy storage and power generation system and method based on jet flash evaporation. Background Technology

[0002] The mismatch between the electricity generated and the electricity consumed by users at different times leads to power shortages and insufficient voltage during peak hours, while there is an excessive surplus of electricity during off-peak hours.

[0003] Increasing the utilization rate of renewable energy sources such as solar, wind, and biomass energy, and integrating the electricity converted from these renewable energy sources into the power grid, has become a major measure to alleviate power shortages. However, renewable energy power generation, especially wind and solar power, is constantly changing due to environmental influences, exhibiting significant volatility, cyclicality, and uncertainty. As the installed capacity of wind and solar power continues to increase, these drawbacks are amplified, and large-scale grid connection poses unprecedented security challenges to the power grid system. Consequently, some regional power grids refuse to connect wind and solar power or restrict their power generation, resulting in the phenomena of "curtailment" of solar and wind power.

[0004] Existing technologies use compressed air energy storage and expanded air energy release to achieve peak shaving and valley filling in the power grid system. However, this requires not only air storage tanks for storing compressed air, but also high-temperature heat storage tanks for storing high-temperature media and low-temperature heat storage tanks for storing low-temperature media. In addition, multi-stage heat exchange devices are needed to recover and reuse heat during the compression and expansion of air, which is very costly and makes the system complex and large. The complex system structure also makes the response speed of energy storage and release slower and the energy storage and release efficiency lower. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a compressed air energy storage and power generation system based on jet flash evaporation, which can more efficiently regulate the power supply of the power grid during different power consumption periods.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A compressed air energy storage and power generation system based on jet flash evaporation includes a compression subsystem, an energy storage subsystem, and an expansion and energy release subsystem. The compression subsystem consists of two or more compressor units connected in series. The energy storage subsystem includes a storage tank, a first valve, a second valve, a working fluid pump for the storage tank, one or more heat exchangers, a circulating inlet pipe, and a circulating outlet pipe. Each compressor unit includes one compressor, and each compressor is driven by an electric motor to compress air. Each electric motor independently drives its corresponding compressor. The compressor in the first-stage compressor unit draws in ambient temperature and pressure air through its inlet. The compressor in the last-stage compressor unit connects to the inlet of the first valve, and the outlet of the first valve connects to the inlet of the storage tank. The storage tank contains a liquid working fluid, and the lower part of the storage tank is equipped with... It is equipped with a circulating inlet pipe and a circulating outlet pipe. The end of the circulating outlet pipe closest to the storage tank is connected in series with a storage tank working fluid pump and a second valve. The end of the circulating outlet pipe furthest from the storage tank is connected to the inlet pipe on the low-temperature side of the first-stage heat storage heat exchanger. The bottom of the storage tank is equipped with an outlet port connected to the expansion and energy release subsystem. The total number of stages of the heat storage heat exchanger is one less than the total number of stages of the compressor unit. The high-temperature side inlet pipe of each heat storage heat exchanger is connected to the outlet of the compressor in the previous stage compressor unit, and the high-temperature side outlet pipe of each heat storage heat exchanger is connected to the inlet of the compressor in the next stage compressor unit. The low-temperature side outlet pipe of the previous stage heat storage heat exchanger is connected to the low-temperature side inlet pipe of the next stage heat storage heat exchanger, and the low-temperature side outlet pipe of the last stage heat storage heat exchanger is connected to the circulating inlet pipe.

[0008] Preferably, the storage tank also includes a heat exchange coil, which is a bent and coiled hollow metal tube. The upper end of the heat exchange coil is connected to the air inlet of the storage tank, and the lower end of the heat exchange coil is immersed in the liquid working medium in the storage tank.

[0009] Preferably, the storage tank also includes a third valve located on the top of the storage tank. When the third valve is opened, the interior of the storage tank is connected to the external atmospheric environment.

[0010] Preferably, the expansion energy release subsystem includes a fifth valve, an ejector, a flash generator, a sixth valve, and an expansion generator set; the outlet at the bottom of the storage tank is connected to the inlet of the fifth valve, the outlet of the fifth valve is connected to the inlet of the ejector, the outlet of the ejector is connected to the inlet of the flash generator, the first outlet at the top of the flash generator is connected to the inflow end of the sixth valve, and the outflow end of the sixth valve is connected to the expansion generator set.

[0011] Preferably, each stage of the expander generator set includes an expander, and the working fluid in each expander expands to do work and drive the generator to generate electricity.

[0012] Preferably, the outlet of the sixth valve is connected to the expander inlet of the first-stage expander generator set, the expander inlet of each stage expander generator set is connected to the expander outlet of the previous stage expander generator set, and the expander outlet of the last stage expander generator set is connected to the exhaust steam recovery port on the injector through the exhaust steam recovery pipeline.

[0013] Preferably, or when the working medium is pure water, the outlet of the expander in the last stage expander generator set is connected to the external atmospheric environment.

[0014] Preferably, the second outlet at the bottom of the flash generator is connected to the working fluid recovery port on the storage tank via a working fluid recovery pipeline, and a flash generator working fluid pump and a seventh valve are also connected in series on the working fluid recovery pipeline.

[0015] Preferably, the power of each motor comes from surplus electricity, which includes one or more of the following: electricity generated during off-peak hours in the power grid system, wind power generation, and photovoltaic power generation.

[0016] This invention also provides a compressed air energy storage and power generation method based on jet flash evaporation, which is applied to the aforementioned compressed air energy storage and power generation system based on jet flash evaporation.

[0017] When there is surplus electricity, energy storage is performed: the first and second valves are opened, and the third and fifth valves are closed. The air compressed by the compressor in the previous stage compressor unit flows through the high-temperature side of the corresponding heat storage heat exchanger and then enters the compressor in the next stage compressor unit. The high-temperature and high-pressure air compressed by the compressor in the last stage compressor unit enters the storage tank. The high-temperature and high-pressure air in the storage tank exchanges heat with the liquid working fluid. At the same time, the pressure in the storage tank increases, which also increases the pressure of the liquid working fluid in the storage tank. Meanwhile, the liquid working fluid in the storage tank is powered by the storage tank working fluid pump and circulates through the low-temperature side of each stage heat storage heat exchanger to absorb heat before returning to the storage tank. The pressure and temperature of the liquid working fluid in the storage tank increase, and the surplus electricity is finally converted into the internal energy of the liquid working fluid in the storage tank and stored for later use.

[0018] During peak electricity consumption, energy release generates electricity: valves five, six, and seven are opened, while valves one, two, and three are closed. The high-temperature, high-pressure liquid working fluid in the storage tank flows out from the bottom outlet of the tank and into the ejector. After being ejected by the ejector, it enters the flash generator (FT) and becomes a high-temperature, high-pressure gaseous working fluid. The gaseous working fluid in the flash generator flows out from the first outlet at the top of the flash generator and enters each stage of the expander generator set. The gaseous working fluid expands and does work in the expander of each stage of the expander generator set, driving the corresponding generator to generate electricity. At the same time, the exhaust steam at the outlet of the expander in the last stage of the expander generator set returns to the ejector through the exhaust steam recovery pipeline. The liquid working fluid in the flash generator is powered by the flash generator working fluid pump and sent back to the storage tank.

[0019] After the energy release and power generation are completed, close the fifth valve and open the third valve to connect the inside of the storage tank with the external atmospheric environment.

[0020] The beneficial effects of this invention are as follows:

[0021] (1) In the energy storage and power generation system of the present invention, the compression subsystem uses surplus electricity to compress air to obtain high-temperature and high-pressure air. The energy storage subsystem converts the energy in the high-temperature and high-pressure air into the internal energy of the high-temperature and high-pressure liquid working fluid for storage and backup. During peak electricity demand, the expansion and energy release subsystem uses the high-temperature and high-pressure liquid working fluid to expand and generate electricity after flashing into a gaseous working fluid, thus alleviating the power shortage. The energy storage and power generation system of the present invention regulates the power supply of the power grid during different electricity demand periods. The energy storage and power generation system of the present invention can also convert wind power generation and photovoltaic power generation as surplus electricity into the internal energy of the high-temperature and high-pressure liquid working fluid. During peak electricity demand, the high-temperature and high-pressure liquid working fluid expands and generates electricity, which is then fed into the power grid. This solves the problem of obvious fluctuations, periodicity, and uncertainty caused by directly using wind power generation and photovoltaic power generation to alleviate peak electricity demand.

[0022] (2) The compression subsystem of the present invention uses surplus electricity to compress air to obtain high temperature and high pressure air, and stores the high temperature and high pressure air and liquid working medium together in the storage tank. By converting surplus electricity into the internal energy of compressed air, and from the beginning of air compression to the process of compressed air storage in the storage tank, the internal energy of high temperature and high pressure air is converted into the internal energy of liquid working medium in the storage tank through multiple parallel pathways. That is, the surplus electricity is ultimately converted into the internal energy of high temperature and high pressure liquid working medium in the storage tank for storage. Compared with the prior art of storing energy through compressed air and releasing energy through expanded air, the energy storage and power generation system of the present invention does not need to be equipped with a high temperature heat storage tank for storing high temperature liquid medium, a high pressure storage tank for storing high pressure air, and a low temperature heat storage tank for storing low temperature medium. Meanwhile, in the energy release process, this invention directly uses the high-temperature, high-pressure liquid working medium in the storage tank as the working medium for expansion and work, eliminating the need for multi-stage heat exchange devices to recover and reuse heat to raise the air temperature before entering the expander. This avoids the secondary heat exchange process between the air and the liquid heat storage working medium in the heat exchange device, eliminating the need for multiple indirect heat exchange devices, greatly simplifying the structure of the entire energy storage power generation system, and reducing system costs and system efficiency. This reduces energy loss, improves the overall system's energy storage and release response speed, and enhances energy storage and release efficiency.

[0023] (3) The process of heating and pressurizing the liquid working medium in the storage tank of the present invention is carried out simultaneously through multiple pathways from the initial stage of air compression to the storage of compressed air in the storage tank. Therefore, the liquid working medium in the storage tank heats up and pressurizes very quickly. That is, the energy storage power generation system of the present invention further improves the response speed and efficiency of the energy storage process.

[0024] (4) In this invention, the high-temperature and high-pressure air discharged from the last stage compressor unit is directly blown into the liquid working medium in the storage tank through the heat exchange coil. While achieving direct contact heat exchange, the compressed air bubbles in the liquid working medium in the storage tank float and rise to the gas space at the top of the storage tank, which enhances the disturbance of the liquid working medium in the storage tank and strengthens the heat exchange effect.

[0025] (5) This invention equips the expansion energy release subsystem with an ejector and a flash evaporator. During the energy release power generation process, the exhaust steam flowing out of the expander outlet in the last-stage expansion generator unit enters the ejector and mixes with the liquid working fluid flowing into the ejector from the bottom outlet of the storage tank. While adjusting the pressure at the ejector outlet, this also replenishes the total working fluid flow rate entering the subsequent flash evaporators and regulates the pressure of the gaseous working fluid after flashing and vaporization in the flash evaporators entering each stage of the expansion generator unit. This further enhances the working capacity of the working fluid in the expander, enabling the expander to output more mechanical work and drive the generator to generate more electrical energy. In other words, this invention achieves the recovery and reuse of exhaust steam.

[0026] (6) The compression subsystem of the present invention converts air at normal temperature and pressure into high temperature and high pressure air through multi-stage compression, and converts surplus electricity into air internal energy; and the structure of two or more compressor units connected in series increases the working fluid flow of the compression subsystem, which reduces the performance requirements of each compressor while improving the overall pressure ratio of the compression subsystem, avoids knocking caused by excessive pressure ratio of a single compressor, and extends the service life of the compressor.

[0027] (7) During the operation of the flash generator, insufficient flash vaporization may cause some liquid working medium to fail to become gaseous working medium and instead accumulate at the bottom of the flash generator. This invention opens the seventh valve on the working medium recovery pipeline at the bottom of the flash generator, and the working medium pump of the flash generator provides power to send the liquid working medium accumulated at the bottom of the flash generator back to the storage tank. This not only reduces the space occupied by the liquid working medium in the flash generator, but also replenishes the liquid working medium that is constantly decreasing in the storage tank during the energy release and power generation process. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the energy storage power generation system of the present invention;

[0029] Figure 2 This is a schematic diagram of the second internal structure of the storage tank in the energy storage and power generation system of the present invention. Detailed Implementation

[0030] To make the technical solution of the present invention clearer and more explicit, the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Solutions derived by those skilled in the art through equivalent substitution and conventional reasoning of the technical features of the present invention without creative effort all fall within the protection scope of the present invention.

[0031] exist Figure 1 In the diagram, lines indicating whether the device is driven by an electric motor or a generator are represented by bold black lines, while other solid and dashed lines represent pipe connections.

[0032] Example 1

[0033] A compressed air energy storage and power generation system based on jet flash evaporation includes a compression subsystem, an energy storage subsystem, and an expansion and energy release subsystem. The compression subsystem uses surplus electricity to compress air to obtain high-temperature and high-pressure air. The energy storage subsystem converts the energy in the high-temperature and high-pressure air into the internal energy of a high-temperature and high-pressure liquid working fluid, which is stored for later use. During peak electricity demand, the expansion and energy release subsystem uses the high-temperature and high-pressure liquid working fluid to flash into a gaseous working fluid, which then expands to generate electricity and alleviate power shortages.

[0034] like Figure 1 The diagram shown is a schematic representation of the overall structure of a compressed air energy storage and power generation system based on jet flash evaporation according to the present invention.

[0035] 1. Compression Subsystem

[0036] The compression subsystem consists of two or more compressor units connected in series.

[0037] Each stage of the compressor unit includes a compressor AC and an electric motor M; each electric motor M independently drives the corresponding compressor AC to compress the gas discharged from the previous stage compressor unit before discharging it.

[0038] Optionally, the compressors AC in each stage of the compressor unit can be driven simultaneously by a single electric motor M.

[0039] The driving method of the compressor AC and the electric motor M is not intended to limit the invention.

[0040] The compressor AC in the first-stage compressor unit draws in air at normal temperature and pressure through its inlet, while the compressor AC in the last-stage compressor unit connects to the inlet pipe of the energy storage subsystem.

[0041] The power of the motor M comes from surplus electricity, which includes, but is not limited to, electricity generated during off-peak hours of the power grid system and / or other clean energy sources such as wind power, photovoltaic power, and biomass power.

[0042] The compression subsystem transforms ambient air into high-temperature, high-pressure air through multi-stage compression, converting surplus electricity into the internal energy of the air. Furthermore, the series connection of two or more compressor units increases the working fluid flow rate of the compression subsystem, reducing the performance requirements of each compressor while improving the overall pressure ratio of the compression subsystem. This avoids knocking caused by excessive pressure ratio of a single compressor and extends the service life of the compressor.

[0043] Optionally, the gas compressed in the compression subsystem can be other working gases such as carbon dioxide.

[0044] In this embodiment, the compression subsystem consists of a three-stage compressor unit connected in series.

[0045] 2. Energy Storage Subsystem

[0046] The energy storage subsystem includes a storage tank TANK1, a first valve CV1, a second valve CV2, a storage tank working fluid pump PUMP1, a primary or higher-level heat storage heat exchanger HEX1, a circulating inlet pipe, and a circulating outlet pipe.

[0047] In the compression subsystem, the outlet of compressor AC in the last stage compressor unit is connected to the inlet of storage tank TANK1, supplying high-temperature, high-pressure air into TANK1. A first valve CV1 is installed at the inlet of storage tank TANK1. Storage tank TANK1 stores high-temperature, high-pressure air and a liquid working fluid, with the high-temperature, high-pressure air located at the top and the liquid working fluid at the bottom. A circulating liquid inlet pipe and a circulating liquid outlet pipe are located at the bottom of storage tank TANK1. A second valve CV2 and a storage tank working fluid pump PUMP1 are installed at the end of the circulating liquid outlet pipe closest to storage tank TANK1. A liquid outlet is located at the bottom of storage tank TANK1.

[0048] The total number of stages in the heat storage heat exchanger HEX1 is one less than the total number of stages in the compressor unit. The high-temperature side inlet pipe of each heat storage heat exchanger HEX1 is connected to the outlet of the compressor AC in the previous stage compressor unit, and the high-temperature side outlet pipe of each heat storage heat exchanger HEX1 is connected to the inlet of the compressor AC in the next stage compressor unit. The low-temperature side liquid outlet pipe of the previous stage heat storage heat exchanger HEX1 is connected to the low-temperature side liquid inlet pipe of the next stage heat storage heat exchanger HEX1. The low-temperature side liquid inlet pipe of the first stage heat storage heat exchanger HEX1 is connected to the end of the circulating liquid outlet pipe away from the storage tank TANK1. The low-temperature side liquid outlet pipe of the last stage heat storage heat exchanger HEX1 is connected to the circulating liquid inlet pipe.

[0049] In this embodiment, the second valve CV2 and the working fluid pump PUMP1 of the storage tank are connected in series on the circulating liquid outlet pipe, and then connected to the low-temperature side inlet pipe of the first-stage heat storage heat exchanger HEX1. The heat storage heat exchanger HEX1 has two stages. The outlet of the compressor AC in the first-stage compressor unit is connected to the inlet pipe of the high-temperature side of the first-stage heat storage heat exchanger HEX1. The outlet of the high-temperature side of the first-stage heat storage heat exchanger HEX1 is connected to the inlet of the compressor AC in the second-stage compressor unit. The outlet of the compressor AC in the second-stage compressor unit is connected to the inlet pipe of the high-temperature side of the second-stage heat storage heat exchanger HEX1. The outlet of the high-temperature side of the second-stage heat storage heat exchanger HEX1 is connected to the inlet of the compressor AC in the third-stage compressor unit.

[0050] Optionally, the storage tank TANK1 also includes a third valve CV3 located on top of the storage tank TANK1 and connected to the external atmospheric environment.

[0051] 3. Expansion and energy release subsystem

[0052] The expansion energy release subsystem includes the fifth valve CV5, the ejector FM, the flash generator FT, the sixth valve CV6, and the expansion generator set.

[0053] The outlet at the bottom of tank TANK1 is connected to the inlet of valve CV5. The outlet of valve CV5 is connected to the inlet of ejector FM. The outlet of ejector FM is connected to the inlet of flash evaporator FT. The first outlet at the top of flash evaporator FT is connected to the inlet of valve CV6. The outlet of valve CV6 is connected to the first-stage and above expander generator sets. Each stage of the expander generator set includes an expander TE and a generator G. The working fluid expands and performs work in each expander TE, driving the corresponding generator G to generate electricity. The outlet of valve CV6 is connected to the inlet of the expander TE in the first-stage expander generator set. The inlets of the expanders TE in each of the remaining stages of the expander generator set are connected to the outlets of the expanders TE in the previous stage. When the working fluid is pure water, the outlet of the expander TE in the last stage of the expander generator set can be connected to the external atmospheric environment.

[0054] Optionally, the expanders TE in each stage of the expander generator set can be connected to the same generator G. That is, the working fluid expands and does work in each expander TE, which can drive the same generator G to generate electricity. The way in which each expander TE drives the generator G is not a limitation of the present invention.

[0055] Optionally, the second outlet at the bottom of the flash generator FT is connected to the working fluid recovery port on the storage tank TANK1 via a working fluid recovery pipeline, and the working fluid recovery pipeline is also connected in series with the flash generator working fluid pump PUMP3 and the seventh valve CV7.

[0056] In this embodiment, a working fluid pump PUMP3 is installed on the working fluid recovery pipeline near the bottom of the flash generator FT, and a seventh valve CV7 is installed on the working fluid recovery pipeline away from the bottom of the flash generator FT.

[0057] Optionally, the outlet of the expander TE in the last stage expander generator set is not connected to the outside atmosphere, but is connected to the exhaust steam recovery port on the injector FM through the exhaust steam recovery pipeline, and the exhaust steam recovery port is close to the liquid inlet of the injector FM.

[0058] When there is surplus electricity, the energy storage power generation system of this invention stores energy:

[0059] With valve CV5 closed and valve CV1 open, ambient temperature and pressure air enters compressor AC in the first-stage compressor unit and is compressed. As the air pressure and temperature increase, it enters the high-temperature side of the first-stage heat exchanger HEX1. While flowing through the high-temperature side of HEX1, the air exchanges heat with the low-temperature side of HEX1, cooling down before entering compressor AC in the second-stage compressor unit and being compressed again. As the air pressure and temperature increase again, it enters the high-temperature side of HEX1. While flowing through the high-temperature side of HEX1, the air exchanges heat with the low-temperature side of HEX1, cooling down before entering compressor AC in the third-stage compressor unit and being compressed again. As the air pressure and temperature further increase, it enters storage tank TANK1 through its inlet.

[0060] When the top of the storage tank TANK1 is equipped with a third valve CV3, during the energy storage and power generation process of the energy storage and power generation system of the present invention, the third valve CV3 is closed, that is, the third valve CV3 is not connected to the external atmospheric environment.

[0061] During the air compression process of each stage of the compressor, process I also occurs simultaneously: the second valve CV2 opens, and the working fluid pump PUMP1 provides power to the liquid working fluid in the storage tank TANK1 to flow out from the circulation outlet pipe, absorb heat through the low-temperature side of each stage of heat storage heat exchanger HEX1, and then flow into the storage tank TANK1 through the circulation inlet pipe, thereby increasing the overall temperature of the liquid working fluid in the storage tank TANK1.

[0062] like Figure 1As shown, with the increasing amount of compressed air entering through the TANK inlet, the overall pressure inside TANK1 increases, and the pressure of the liquid working fluid inside TANK1 also increases accordingly; simultaneously, the temperature of the liquid working fluid inside TANK1 gradually rises. The temperature increase of the liquid working fluid inside TANK1 is mainly due to two factors: first, process I; and second, the high-temperature compressed air in the upper part of TANK1 transfers heat through contact with the surface of the liquid working fluid. In other words, these two pathways occur simultaneously, causing the liquid working fluid inside TANK1 to rapidly increase in temperature and pressure.

[0063] Unlike Figure 1 The internal structure of the medium storage tank TANK1, such as Figure 2 The diagram shows a second internal structure of the storage tank TANK1 in the energy storage and power generation system of the present invention. The storage tank TANK1 also includes a heat exchange coil HCP, which is a bent, coiled, and hollow metal tube. The upper end of the heat exchange coil HCP is connected to the air inlet of the storage tank TANK, and the lower end of the heat exchange coil HCP is immersed in the liquid working medium in the storage tank TANK. In this embodiment, the lower part of the heat exchange coil HCP is immersed in the liquid working medium in the storage tank TANK1.

[0064] The heat exchange coil HCP in this invention is not limited to a spiral structure.

[0065] More and more compressed air enters from the TANK inlet, flows into the HCP heat exchange coil from the upper end, and flows out from the lower end. During this process, the pressure of the liquid working fluid in TANK1 increases accordingly; simultaneously, the temperature of the liquid working fluid in TANK1 also gradually rises. That is, when the internal structure of TANK1 is as follows... Figure 2 As shown, the temperature rise of the liquid working fluid in tank TANK1 is mainly due to four factors: First, process I; second, during the process of compressed air flowing out from the lower end of the heat exchange coil HCP, some of the heat in the compressed air is transferred to the liquid working fluid through the part of the heat exchange coil HCP immersed in the liquid working fluid; third, after the compressed air flows out from the lower end of the heat exchange coil HCP, it rises in the liquid working fluid in the form of bubbles until it floats out and enters the gas space in the upper part of tank TANK, where the high-temperature bubbles fully contact and exchange heat with the surrounding liquid working fluid; fourth, the high-temperature compressed air in the upper part of tank TANK1 transfers heat through contact with the surface of the liquid working fluid. In other words, these four pathways occur simultaneously, causing the liquid working fluid in tank TANK1 to rapidly increase in temperature and pressure.

[0066] In this invention, the surplus electricity is ultimately converted into the internal energy of the high-temperature and high-pressure liquid working medium in the storage tank TANK1. As can be seen from the above analysis, the heating and pressurization process of the liquid working medium in the storage tank TANK1 is carried out simultaneously through multiple pathways during the staged compression of air in the compressed air subsystem. Therefore, the heating and pressurization of the liquid working medium in the storage tank TANK1 is very rapid, that is, the energy storage process of the energy storage power generation system of this invention is rapid and efficient.

[0067] During peak electricity demand periods, the energy storage power generation system of this invention releases energy to generate electricity:

[0068] The first valve CV1 and the second valve CV2 are both closed, while the fifth valve CV5 and the sixth valve CV6 are open. When the third valve CV3 is installed on the top of the storage tank TANK1, the third valve CV3 is closed during the energy release and power generation process of the energy storage power generation system of the present invention, that is, the third valve CV3 is not connected to the external atmospheric environment.

[0069] The high-temperature, high-pressure liquid working fluid in tank TANK1 flows out from the bottom outlet and into ejector FM. After being ejected by ejector FM, the liquid working fluid enters flash evaporator FT and flashes into a high-temperature, high-pressure gaseous working fluid. The gaseous working fluid in flash evaporator FT flows out from the first outlet at the top of flash evaporator FT and enters each stage of the expander generator set. The gaseous working fluid expands and does work in the expander TE in each stage of the expander generator set, driving the corresponding generator G to generate electricity. The process of the gaseous working fluid expanding and doing work in the expander TE in each stage of the expander generator set achieves the gradual expansion, cooling, and depressurization of the gaseous working fluid, making full use of the internal energy of the gaseous working fluid. The gaseous working fluid discharged from the outlet of the expander TE in the last stage of the expander generator set is a low-temperature, low-pressure gaseous working fluid.

[0070] During the energy release and power generation process of the energy storage power generation system, if the second outlet at the bottom of the flash generator FT is connected to the working fluid recovery port on the storage tank TANK1 via a working fluid recovery pipeline, and the working fluid recovery pipeline is also connected in series with the flash generator working fluid pump PUMP3 and the seventh valve CV7, the seventh valve CV7 will also open. During the operation of the flash generator FT, due to insufficient flash vaporization, some liquid working fluid may not be converted into gaseous working fluid and instead accumulate at the bottom of the flash generator FT. When the seventh valve CV7 opens, the flash generator working fluid pump PUMP3 provides power to send the liquid working fluid accumulated at the bottom of the flash generator FT back into the storage tank TANK1. This not only reduces the space occupied by the liquid working fluid in the flash generator FT, but also replenishes the liquid working fluid that continuously decreases in the storage tank TANK1 during the energy release and power generation process.

[0071] When the outlet of the expander TE in the last stage expander generator set is not connected to the external atmospheric environment, but is connected to the exhaust steam recovery port set on the ejector FM through the exhaust steam recovery pipeline, the working gas with a certain temperature and pressure, that is, the exhaust steam, flows out of the outlet of the expander TE in the last stage expander generator set and enters the ejector FM from the exhaust steam recovery port. Under the action of the ejector FM, the exhaust steam is entrained and mixed with the liquid working gas flowing into the ejector FM from the liquid outlet at the bottom of the storage tank TANK1. While adjusting the pressure at the liquid outlet of the ejector FM, it also replenishes the total working gas flow rate entering the subsequent flash generator FT and each stage of the expander generator set, further improving the working capacity of the working gas in the expander TE, enabling the expander TE to output more mechanical work and drive the generator G to generate more electrical energy.

[0072] When the energy storage and power generation system of the present invention finishes releasing energy and generating electricity, and when the storage tank TANK1 also includes a third valve CV3 located on the top of the storage tank TANK1, the third valve CV3 is opened to connect the inside of the storage tank TANK1 with the external atmospheric environment, and the pressure inside the storage tank TANK1 is restored to the atmospheric pressure, so that the storage tank TANK1 is ready for the next energy storage of the energy storage and power generation system of the present invention.

[0073] When the energy storage and power generation system of the present invention finishes releasing energy and generating electricity, if the storage tank TANK1 is not equipped with a valve that connects to the external atmospheric environment when opened, the excess pressure of the storage tank TANK1 can be released to the external atmospheric environment through the pipeline of the non-working compression subsystem by opening the first valve CV1.

[0074] In the energy storage and power generation system of this invention, the circulating liquid working medium can be water or other organic working media to adapt to different operating pressures and temperatures. Similarly, the number of compressor stages and / or expander generator stages in the energy storage and power generation system of this invention are determined by the operators based on the actual pressure ratio, target pressure operating requirements, and expansion ratio.

[0075] In the energy storage and power generation system of this invention, the compression subsystem utilizes surplus electricity to compress air to obtain high-temperature, high-pressure air. The energy storage subsystem converts the energy in the high-temperature, high-pressure air into the internal energy of a high-temperature, high-pressure liquid working fluid for storage and backup. During peak electricity demand, the expansion and energy release subsystem uses the high-temperature, high-pressure liquid working fluid to expand and generate electricity after flashing into a gaseous working fluid, thus alleviating power shortages. This energy storage and power generation system of the present invention regulates the power supply of the grid during different electricity demand periods. Furthermore, this energy storage and power generation system can uniformly convert surplus electricity from wind power and photovoltaic power into the internal energy of a high-temperature, high-pressure liquid working fluid. During peak electricity demand, the high-temperature, high-pressure liquid working fluid expands and generates electricity, which is then uniformly fed into the grid. This solves the problem of directly using wind power and photovoltaic power to alleviate the volatility, periodicity, and uncertainty caused by peak electricity demand.

[0076] The compression subsystem utilizes surplus electricity to compress air to obtain high-temperature, high-pressure air, and stores the high-temperature, high-pressure air and liquid working medium together in the storage tank TANK1. By converting surplus electricity into the internal energy of compressed air, and through multiple parallel pathways from the start of air compression to its storage in the storage tank TANK1, the internal energy of the high-temperature, high-pressure air is converted into the internal energy of the liquid working medium in the storage tank TANK1. In other words, the surplus electricity is ultimately converted into the internal energy of the high-temperature, high-pressure liquid working medium in the storage tank TANK1 for storage. Compared with the existing technology of storing energy through compressed air and releasing energy through expanded air, the energy storage and power generation system of the present invention does not require separate high-temperature heat storage tank for storing high-temperature liquid medium, high-pressure storage tank for storing high-pressure air, and low-temperature heat storage tank for storing low-temperature medium. Furthermore, unlike conventional compressed air energy storage systems in the prior art, this invention does not employ air expansion to output mechanical work during the energy release process. Instead, it directly uses the high-temperature, high-pressure liquid working medium in the storage tank TANK1 as the working medium for expansion and work. This eliminates the need for multi-stage heat exchange devices to recover and reuse heat to raise the air temperature before it enters the expander. It also avoids the secondary heat exchange process between the air and the liquid heat storage working medium in the heat exchange device, eliminating the need for multiple indirect heat exchange devices. This significantly simplifies the structure of the entire energy storage and power generation system, reducing system costs and system efficiency. This reduces energy loss, improves the overall system's energy storage and release response speed, and enhances energy storage and release efficiency.

[0077] During the energy storage process of this invention, as more and more compressed air enters the storage tank TANK1, the pressure of the liquid working fluid inside TANK1 continuously increases. Simultaneously, when the storage tank TANK1 does not include the heat exchange coil HCP, the synchronous heating pathways of the liquid working fluid include:

[0078] ① The liquid working fluid circulates through the low-temperature side of the HEX1 heat exchangers at each stage to absorb heat.

[0079] ② The high-temperature compressed air in the upper part of the storage tank TANK1 transfers heat by contacting the surface of the liquid working fluid.

[0080] When the storage tank TANK1 includes a heat exchange coil HCP, the synchronous heating pathways of the liquid working fluid include:

[0081] ① The liquid working fluid circulates through the low-temperature side of the HEX1 heat exchangers at each stage to absorb heat.

[0082] ② During the process of compressed air flowing out from the lower end of the heat exchange coil HCP, some of the heat in the compressed air is transferred to the liquid working medium through the part of the heat exchange coil HCP immersed in the liquid working medium.

[0083] ③ After the compressed air flows out from the lower end of the heat exchange coil (HCP), it rises in the liquid working fluid in the form of bubbles until it floats up and enters the gas space at the top of the tank. The high-temperature bubbles fully contact and exchange heat with the surrounding liquid working fluid.

[0084] ④ The high-temperature compressed air in the upper part of the storage tank TANK1 transfers heat by contacting the surface of the liquid working fluid.

[0085] As can be seen from the above analysis, the process of heating and pressurizing the liquid working medium in the storage tank TANK1 of the present invention is carried out simultaneously through multiple pathways from the initial stage of air compression to the storage of compressed air in the storage tank TANK1. Therefore, the liquid working medium in the storage tank TANK1 heats up and pressurizes very rapidly. That is, the energy storage power generation system of the present invention further improves the response speed and efficiency of the energy storage process.

[0086] This invention directly blows the high-temperature, high-pressure air discharged from the last stage compressor unit into the liquid working medium in the storage tank TANK1 through the heat exchange coil HCP, achieving direct contact heat exchange. At the same time, the compressed air bubbles in the liquid working medium in the storage tank TANK1 float and rise to the gas space at the top of the storage tank TANK1, enhancing the disturbance of the liquid working medium in the storage tank TANK1 and strengthening the heat exchange effect.

[0087] This invention equips the expansion energy release subsystem with an ejector FM and a flash evaporator FT. During the energy release power generation process, the exhaust steam flowing from the outlet of the expander TE in the last-stage expander generator unit enters the ejector FM and mixes with the liquid working fluid flowing into the ejector FM from the bottom outlet of the storage tank TANK1. While adjusting the pressure at the outlet of the ejector FM, this mixture simultaneously replenishes the total working fluid flow rate entering the subsequent flash evaporator FT and regulates the pressure of the gaseous working fluid after flash vaporization in the flash evaporator FT entering each stage of the expander generator unit. This further enhances the work capacity of the working fluid in the expander TE, enabling the expander TE to output more mechanical work and drive the generator G to generate more electrical energy. In other words, this invention achieves the recovery and reuse of exhaust steam.

[0088] Example 2

[0089] The present invention also provides a compressed air energy storage and power generation method based on jet flash evaporation, which is applied to a compressed air energy storage and power generation system based on jet flash evaporation as described in Example 1.

[0090] When there is surplus electricity, energy storage is carried out, including the following:

[0091] Open the first valve CV1 and the second valve CV2, and close the third valve CV3 and the fifth valve CV5. The air compressed by the compressor AC in the previous stage compressor unit flows through the high-temperature side of the corresponding heat storage heat exchanger HEX1 and then enters the compressor AC in the next stage compressor unit. The high-temperature and high-pressure air compressed by the compressor AC in the last stage compressor unit enters the storage tank TANK1. The high-temperature and high-pressure air in the storage tank TANK1 exchanges heat with the liquid working fluid. At the same time, the pressure in the storage tank TANK1 increases, which also increases the pressure of the liquid working fluid in the storage tank TANK1. Meanwhile, the liquid working fluid in the storage tank TANK1 is powered by the storage tank working fluid pump PUMP1 and circulates through the low-temperature side of each stage heat storage heat exchanger HEX1 to absorb heat before returning to the storage tank TANK1. The pressure and temperature of the liquid working fluid in the storage tank TANK1 continue to rise, and the surplus electricity is finally converted into the internal energy of the liquid working fluid in the storage tank TANK1 and stored for later use.

[0092] During peak electricity demand periods, energy is released to generate electricity, including the following:

[0093] Open valves CV5, CV6, and CV7, and close valves CV1, CV2, and CV3. The high-temperature, high-pressure liquid working fluid in tank TANK1 flows out from the bottom outlet of tank TANK1 and into ejector FM. After being ejected by ejector FM, it enters flash generator FT and becomes a high-temperature, high-pressure gaseous working fluid. The gaseous working fluid in flash generator FT flows out from the first outlet at the top of flash generator FT and enters each stage of the expander generator set. The gaseous working fluid expands and does work in the expander TE in each stage of the expander generator set, driving the corresponding generator G to generate electricity. At the same time, the exhaust steam at the outlet of the expander TE in the last stage of the expander generator set returns to ejector FM through the exhaust steam recovery pipeline. The liquid working fluid in flash generator FT is powered by flash generator working fluid pump PUMP3 and sent back to tank TANK1.

[0094] After the energy release and power generation are completed, close the fifth valve CV5 and open the third valve CV3 to connect the interior of the storage tank TANK1 with the external atmospheric environment.

[0095] The technologies, shapes, and structures not described in detail in this invention are all well-known technologies. It should also be noted that the above are merely preferred embodiments of this invention and are not intended to limit the scope of the invention. The components or steps in the embodiments of this invention can be decomposed and / or recombined, and these decompositions and / or recombinations should be considered equivalent solutions to this application and should all fall within the protection scope of this invention.

Claims

1. A compressed air energy storage and power generation system based on jet flash evaporation, characterized in that: It includes a compression subsystem, an energy storage subsystem, and an expansion and energy release subsystem; The compression subsystem consists of more than two stages of compressor units connected in series; the energy storage subsystem includes storage tank TANK1, first valve CV1, second valve CV2, storage tank working fluid pump, more than one stage of heat storage heat exchanger HEX1, circulating inlet pipe and circulating outlet pipe; Each stage of the compressor unit includes one compressor AC. Each compressor AC is driven by an electric motor M to compress air. The air inlet of the compressor AC in the first stage compressor unit draws in air at normal temperature and pressure. The air outlet of the compressor AC in the last stage compressor unit is connected to the air inlet of the first valve CV1. The air outlet of the first valve CV1 is connected to the air inlet of the storage tank TANK1. The storage tank TANK1 contains a liquid working fluid. A circulating liquid inlet pipe and a circulating liquid outlet pipe are installed at the bottom of the storage tank TANK1. A storage tank working fluid pump and a second valve CV2 are connected in series on the end of the circulating liquid outlet pipe closest to the storage tank TANK1. The end of the circulating liquid outlet pipe furthest from the storage tank TANK1 is connected to the first stage of the storage tank TANK1. The inlet pipe of the low-temperature side of the heat exchanger HEX1 is connected; the bottom of the storage tank TANK1 is provided with an outlet connected to the expansion and energy release subsystem; the total number of stages of the heat storage heat exchanger HEX1 is one less than the total number of stages of the compressor unit; the high-temperature side inlet pipe of each heat storage heat exchanger HEX1 is connected to the outlet of the compressor AC in the previous stage compressor unit; the high-temperature side outlet pipe of each heat storage heat exchanger HEX1 is connected to the inlet of the compressor AC in the next stage compressor unit; the low-temperature side outlet pipe of the previous stage heat storage heat exchanger HEX1 is connected to the inlet pipe of the low-temperature side of the next stage heat storage heat exchanger HEX1; and the low-temperature side outlet pipe of the last stage heat storage heat exchanger HEX1 is connected to the circulating inlet pipe. The expansion energy release subsystem includes the fifth valve CV5, ejector FM, flash generator FT, sixth valve CV6, and expansion generator set; the liquid outlet at the bottom of the storage tank TANK1 is connected to the liquid inlet of the fifth valve CV5, the liquid outlet of the fifth valve CV5 is connected to the liquid inlet of the ejector FM, the liquid outlet of the ejector FM is connected to the inlet of the flash generator FT, the first outlet at the top of the flash generator FT is connected to the inflow end of the sixth valve CV6, and the outflow end of the sixth valve CV6 is connected to the expansion generator set.

2. The compressed air energy storage and power generation system based on jet flash evaporation according to claim 1, characterized in that: The storage tank TANK1 also includes a heat exchange coil HCP, which is a bent and coiled hollow metal tube. The upper end of the heat exchange coil HCP is connected to the air inlet of the storage tank TANK, and the lower end of the heat exchange coil HCP is immersed in the liquid working medium in the storage tank TANK.

3. The compressed air energy storage and power generation system based on jet flash evaporation according to claim 2, characterized in that: The storage tank TANK1 also includes a third valve CV3 located on top of the storage tank TANK1. When the third valve CV3 is opened, the interior of the storage tank TANK1 is connected to the external atmospheric environment.

4. The compressed air energy storage and power generation system based on jet flash evaporation according to claim 3, characterized in that: The expansion energy release subsystem includes an expansion generator set with more than one stage. The expansion generator set includes an expander TE and a generator G. The working fluid in the expander TE expands and does work to drive the generator G to generate electricity.

5. A compressed air energy storage and power generation system based on jet flash evaporation according to claim 4, characterized in that: The outlet of the sixth valve CV6 is connected to the expander TE inlet of the first-stage expander generator set. The expander TE inlets of each stage expander generator set are connected to the expander TE outlets of the previous stage expander generator set. The expander TE outlet of the last stage expander generator set is connected to the exhaust steam recovery port on the injector FM through the exhaust steam recovery pipeline.

6. A compressed air energy storage and power generation system based on jet flash evaporation according to claim 5, characterized in that: Alternatively, when the working medium is pure water, the outlet of the expander TE in the last stage expander generator set is connected to the external atmospheric environment.

7. A compressed air energy storage and power generation system based on jet flash evaporation according to claim 5, characterized in that: The second outlet at the bottom of the flash generator FT is connected to the working fluid recovery port on the storage tank TANK1 via a working fluid recovery pipeline, and the working fluid recovery pipeline is also connected in series with the flash generator working fluid pump and the seventh valve CV7.

8. A compressed air energy storage and power generation system based on jet flash evaporation according to claim 7, characterized in that: The power of each motor M comes from surplus electricity, which includes one or more of the following: electricity generated during off-peak hours in the power grid system, wind power generation, and photovoltaic power generation.

9. A compressed air energy storage and power generation method based on jet flash evaporation, wherein the energy storage and power generation method is applied to a compressed air energy storage and power generation system based on jet flash evaporation as described in claim 8, characterized in that: When there is surplus electricity, energy storage is performed: the first valve CV1 and the second valve CV2 are opened, and the third valve CV3 and the fifth valve CV5 are closed. The air compressed by the compressor AC in the previous stage compressor unit flows through the high-temperature side of the corresponding heat storage heat exchanger HEX1 and then enters the compressor AC in the next stage compressor unit. The high-temperature and high-pressure air compressed by the compressor AC in the last stage compressor unit enters the storage tank TANK1. The high-temperature and high-pressure air in the storage tank TANK1 exchanges heat with the liquid working fluid. At the same time, the pressure in the storage tank TANK1 increases, which also increases the pressure of the liquid working fluid in the storage tank TANK1. Meanwhile, the liquid working fluid in the storage tank TANK1 is powered by the storage tank working fluid pump and circulates through the low-temperature side of each stage heat storage heat exchanger HEX1 to absorb heat before returning to the storage tank TANK1. The pressure and temperature of the liquid working fluid in the storage tank TANK1 increase, and the surplus electricity is converted into the internal energy of the liquid working fluid in the storage tank TANK1 and stored for later use. During peak electricity consumption, energy is released for power generation: valves CV5, CV6, and CV7 are opened, and valves CV1, CV2, and CV3 are closed. The high-temperature, high-pressure liquid working fluid in tank TANK1 flows out from the bottom outlet of tank TANK1 and into ejector FM. After being ejected by ejector FM, it enters flash generator FT and becomes a high-temperature, high-pressure gaseous working fluid. The gaseous working fluid in flash generator FT flows out from the first outlet at the top of flash generator FT and enters each stage of the expander generator set. The gaseous working fluid expands and does work in the expander TE in each stage of the expander generator set, driving the corresponding generator G to generate electricity. At the same time, the exhaust steam at the outlet of the expander TE in the last stage of the expander generator set returns to ejector FM through the exhaust steam recovery pipeline. The liquid working fluid in flash generator FT is powered by the flash generator working fluid pump and sent back to tank TANK1. After the energy release and power generation are completed, close the fifth valve CV5 and open the third valve CV3 to connect the interior of the storage tank TANK1 with the external atmospheric environment.

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