Water and electricity cogeneration system and method for improving compression energy storage gas-liquid conversion efficiency

Abstract

The invention relates to the technical field of physical energy storage, in particular to a water and electricity cogeneration system and method for improving compression energy storage gas-liquid conversion efficiency, and can solve the problem of energy loss caused by a large amount of heat absorption and release in the liquefaction process and gasification process of a carbon dioxide energy storage system under conventional conditions to a certain extent. The system is composed of a carbon dioxide loop, a heat storage loop and a seawater desalination loop, compressed carbon dioxide energy storage and a hot-method seawater desalination structure can be ingeniously combined, heat released in the liquefaction process is used for heating seawater, heat of high-temperature saline water is used for achieving carbon dioxide gasification, the efficiency of an energy storage system is improved, and energy consumption and heat pollution of the seawater desalination system are reduced. Peak clipping and valley filling of power loads can be achieved, consumption of renewable energy sources is promoted, and the method is of great significance to energy conservation, emission reduction and energy transformation.

Description

Technical Field

[0001] The present application relates to the field of physical energy storage technology, and more specifically, to a hydropower cogeneration system and method for improving the gas-liquid conversion efficiency of compressed energy storage. Background Art

[0002] In recent years, installed capacity of renewable energy generation, represented by wind and solar power, has grown rapidly. However, the volatility of renewable energy has led to widespread curtailment of wind and solar power. Energy storage technology can regulate power supply and demand, effectively promoting the accessibility and absorption of renewable energy generation.

[0003] Compressed carbon dioxide energy storage is a new physical energy storage technology with unique advantages, including high energy density, unrestricted geographical conditions, and the ability to provide rotational inertia. It is a key technology for large-scale, long-term energy storage. However, to increase energy storage density and reduce tank volume and investment costs, compressed carbon dioxide energy storage systems involve the absorption and release of large amounts of low-grade heat during the liquefaction and vaporization processes of the working fluid, resulting in significant energy losses and, in turn, affecting storage efficiency.

[0004] On the other hand, the demand for fresh water in modern society is increasing day by day. Seawater desalination technologies mainly include reverse osmosis and thermal methods. The latter mainly includes multi-stage flash evaporation technology and multi-effect evaporation technology. Reverse osmosis requires high-grade electricity, while thermal methods can utilize low-grade thermal energy. Therefore, thermal methods are widely used in waste heat recovery, thermal power plants and other fields.

[0005] However, regardless of multi-stage flash evaporation technology or multi-effect evaporation technology, the flow rate of high-concentration brine produced is much greater than the flow rate of fresh water produced, and the temperature of the high-concentration brine produced is higher than the seawater temperature. Directly discharging brine into the ocean will cause certain thermal pollution. Summary of the Invention

[0006] In order to solve the energy loss problem caused by the large amount of heat absorption and release during the liquefaction and gasification processes of the carbon dioxide energy storage system under conventional conditions, as well as the thermal pollution problem of thermal seawater desalination, the present application provides a hydropower cogeneration system and method for improving the gas-liquid conversion efficiency of compressed energy storage.

[0007] The embodiment of the present application is implemented as follows:

[0008] In a first aspect, the present application provides a hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage, comprising a carbon dioxide circuit, a thermal storage circuit, and a seawater desalination circuit;

[0009] The carbon dioxide circuit includes a low-pressure storage tank, a compressor, a first heat exchanger, a condenser, a high-pressure storage tank, an evaporator, a second heat exchanger, a turbine and a cooler connected in series;

[0010] The heat storage circuit includes a cold storage tank and a heat storage tank, wherein the cold storage tank outlet is connected to the cold side inlet of the first heat exchanger, and the cold storage tank inlet is connected to the hot side outlet of the second heat exchanger, and the heat storage tank inlet is connected to the cold side outlet of the first heat exchanger, and the heat storage tank outlet is connected to the hot side inlet of the second heat exchanger;

[0011] The seawater desalination circuit includes a thermal seawater desalination component, a fresh water tank and a heat source device, wherein the seawater inlet is connected to the cold side outlet of the condenser and the cold side outlet of the cooler, the steam inlet of the thermal seawater desalination component is connected to the outlet of the heat source device, the fresh water outlet of the thermal seawater desalination component is connected to the fresh water tank, the brine outlet of the thermal seawater desalination component is connected to the hot side inlet of the evaporator, and the condensate outlet of the thermal seawater desalination component is connected to the inlet of the heat source device.

[0012] In a possible implementation, the low-pressure storage tank outlet is provided with a low-pressure valve, and the high-pressure storage tank outlet is provided with a high-pressure valve.

[0013] In a possible implementation, a low-temperature circulation pump is provided at the outlet of the cold storage tank, and a high-temperature circulation pump is provided at the outlet of the heat storage tank.

[0014] In a possible implementation, the low-pressure storage tank, the high-pressure storage tank, the cold storage tank, and the heat storage tank are all provided with an insulation layer on the outside.

[0015] In a possible implementation, the carbon dioxide discharged from the condenser outlet is in a liquid state, and the carbon dioxide discharged from the evaporator outlet is in a gaseous state.

[0016] In a possible implementation, the thermal seawater desalination component adopts multi-stage flash evaporation technology or multi-effect evaporation technology.

[0017] In a possible implementation, the condenser and the evaporator are thermal storage heat exchangers.

[0018] In a possible implementation, the compression module is composed of a single-stage or multi-stage compression process, and the expansion module is composed of a single-stage or multi-stage expansion process.

[0019] In a possible implementation, the compressor is connected to an electric motor, and the turbine is connected to a generator.

[0020] In a second aspect, the present application provides a method for a hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage, including an energy storage process and an energy release process;

[0021] The energy storage process includes:

[0022] The low-pressure carbon dioxide flows out of the low-pressure storage tank, is compressed by the compressor, and enters the first heat exchanger for cooling, and then is liquefied in the condenser. The liquid carbon dioxide is stored in the high-pressure storage tank. The compressor is driven by a motor generated by renewable energy;

[0023] At the same time, the heat storage medium is controlled to flow out of the cold storage tank and enter the first heat exchanger to absorb heat, and then the heated heat storage medium is stored in the heat storage tank;

[0024] At the same time, seawater is controlled to flow into the cold side inlet of the condenser. After absorbing heat and heating up, it enters the seawater desalination component. The steam generated by the heat source equipment drives the thermal seawater desalination component to desalinate the seawater at the condenser outlet. The steam condenses and then re-enters the heat source equipment. The generated fresh water is stored in the fresh water tank. The generated high-concentration brine enters the evaporator to release heat, completing the energy storage process.

[0025] The energy release process includes:

[0026] The high-pressure liquid carbon dioxide flows into the evaporator to absorb heat and turn into gas, then enters the second heat exchanger to absorb heat and increase temperature, and then enters the turbine to expand and produce work. The turbine drives the generator to generate electricity and transmit it to the power grid. The carbon dioxide at the turbine outlet enters the cooler to be cooled and stored in a low-pressure storage tank.

[0027] At the same time, the heat storage medium is controlled to flow out of the heat storage tank and enter the hot side inlet of the second heat exchanger, and the heat storage medium that releases heat is stored in the cold storage tank;

[0028] At the same time, the seawater is controlled to flow into the cold side inlet of the cooler, and enters the seawater desalination component after absorbing heat and heating up. The steam generated by the heat source equipment drives the thermal seawater desalination component to desalinate the seawater at the cooler outlet, and drives the steam to condense and then re-enter the heat source equipment. The generated fresh water is stored in the fresh water tank, and the generated high-concentration brine enters the evaporator to release heat, completing the energy release process.

[0029] The technical solution provided by this application can achieve at least the following beneficial effects:

[0030] The hydropower cogeneration system and method provided in this application for improving the gas-liquid conversion efficiency of compressed energy storage uses renewable energy such as wind energy and solar energy as input and carbon dioxide as the energy storage fluid. The unstable wind energy and solar energy are converted into the pressure potential energy and internal energy of the carbon dioxide working fluid through a compressor for storage, and the stored energy is stably released through a turbine when needed.

[0031] The main advantage is that the waste heat of the carbon dioxide energy storage system is used to preheat seawater, thereby reducing the heat consumption of the thermal seawater desalination system and increasing freshwater production; the heat of the high-temperature brine generated by the thermal seawater desalination system is used to realize the gasification of the carbon dioxide energy storage system, which reduces the heat demand of the working fluid in the energy release process on the heat storage circuit, reduces the heat loss in the gasification process, improves the efficiency of the energy storage system, and at the same time reduces the environmental impact caused by the discharge of high-temperature brine.

[0032] In summary, this application can reduce energy loss during the liquefaction and gasification processes of the energy storage system, improve the circulation efficiency of the compressed carbon dioxide energy storage system, increase the output of the seawater desalination system, and reduce the energy consumption and thermal pollution of seawater desalination. It has important practical value, economic value and environmental value. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0034] Figure 1 This is a structural diagram of a hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage, as shown in an embodiment of the present application;

[0035] Figure 2 Schematic diagram of the energy storage process of a hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage, as shown in an embodiment of the present application;

[0036] Figure 3 It is a schematic diagram of the energy release process of a hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage, as shown in an embodiment of the present application.

[0037] Reference numerals:

[0038] 1. Low-pressure storage tank; 2. Low-pressure valve; 3. Compressor; 4. First heat exchanger; 5. Condenser; 6. High-pressure storage tank; 7. High-pressure valve; 8. Evaporator; 9. Second heat exchanger; 10. Turbine; 11. Cooler; 12. Cold storage tank; 13. Low-temperature pump; 14. Heat storage tank; 15. High-temperature pump; 16. Thermal desalination unit; 17. Fresh water tank; 18. Heat source equipment; 19. Motor; 20. Generator. DETAILED DESCRIPTION

[0039] In order to make the purpose, implementation methods and advantages of the present application clearer, the exemplary implementation methods of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, not all of the embodiments. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

[0040] It should be noted that the brief descriptions of terms in this application are only for the purpose of facilitating the understanding of the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their ordinary and usual meanings.

[0041] In the specification and claims of this application and the accompanying drawings, the terms "first," "second," "third," etc. are used to distinguish similar or similar objects or entities, and are not necessarily intended to limit a particular order or sequence, unless otherwise noted. It should be understood that the terms used in this manner are interchangeable under appropriate circumstances.

[0042] The terms "comprise," "include," and "have," and any variations thereof, are intended to cover but not exclude inclusion; for example, a product or device comprising a list of components is not necessarily limited to all the components expressly listed but may include other components not expressly listed or inherent to such product or device.

[0043] Before explaining the hydropower cogeneration system and method for improving the gas-liquid conversion efficiency of compressed energy storage provided in the embodiments of the present application, the application scenarios and implementation environment of the embodiments of the present application are first introduced.

[0044] In recent years, installed capacity of renewable energy generation, represented by wind and solar power, has grown rapidly. However, the volatility of renewable energy has led to widespread curtailment of wind and solar power. Energy storage technology can regulate power supply and demand, effectively promoting the accessibility and absorption of renewable energy generation, and is a key technical support for achieving the dual-carbon strategy.

[0045] Compressed carbon dioxide energy storage is a new physical energy storage technology with unique advantages, including high energy density, unrestricted geographical conditions, and the ability to provide rotational inertia. It is a key technology for large-scale, long-term energy storage. However, to increase energy storage density and reduce tank size and investment, compressed carbon dioxide energy storage systems involve the absorption and release of large amounts of low-grade heat during the liquefaction and vaporization processes of the working fluid, resulting in significant energy losses and, in turn, affecting storage efficiency.

[0046] On the other hand, the demand for fresh water in modern society is increasing day by day. Seawater desalination technologies mainly include reverse osmosis and thermal methods. The latter mainly includes multi-stage flash evaporation technology and multi-effect evaporation technology. Reverse osmosis requires high-grade electricity, while thermal methods can utilize low-grade thermal energy. Therefore, thermal methods are widely used in waste heat recovery, thermal power plants and other fields.

[0047] However, regardless of multi-stage flash evaporation technology or multi-effect evaporation technology, the flow rate of high-concentration brine produced is much greater than the flow rate of fresh water produced, and the temperature of the high-concentration brine produced is higher than the seawater temperature. Directly discharging brine into the ocean will cause certain thermal pollution.

[0048] Based on this, the present application provides a hydropower cogeneration system and method for improving the gas-liquid conversion efficiency of compressed energy storage, cleverly combining the structure of compressed carbon dioxide energy storage with thermal seawater desalination, using the heat from the gasification and cooling process of the carbon dioxide energy storage system to increase the seawater feed temperature, and using high-temperature brine to achieve the gasification of liquid carbon dioxide, solving the energy loss problem caused by the large amount of heat absorption and release during the liquefaction and gasification processes of the carbon dioxide energy storage system under conventional conditions, and reducing the energy consumption and thermal pollution of the seawater desalination system. This application helps to achieve peak shaving and valley filling of power loads, promote the consumption of renewable energy, and improve the comprehensive performance of the energy storage system and the seawater desalination system, which is of great significance to energy conservation, emission reduction and energy transformation.

[0049] Next, the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems will be described in detail through embodiments and in conjunction with the accompanying drawings. The various embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, not all of them.

[0050] Figure 1 It is a structural schematic diagram of a hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage, shown in an exemplary embodiment of the present application.

[0051] In an exemplary embodiment, Figure 1 As shown, a water and power cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage is provided, which can include a carbon dioxide loop, a heat storage loop and a seawater desalination loop;

[0052] The carbon dioxide circuit includes a low-pressure storage tank 1, a compressor 3, a first heat exchanger 4, a condenser 5, a high-pressure storage tank 6, an evaporator 8, a second heat exchanger 9, a turbine 10 and a cooler 11 connected in series in sequence;

[0053] The heat storage circuit includes a cold storage tank 12 and a heat storage tank 14, the outlet of the cold storage tank 12 is connected to the cold side inlet of the first heat exchanger 4, the inlet of the cold storage tank 12 is connected to the hot side outlet of the second heat exchanger 9, the inlet of the heat storage tank 14 is connected to the cold side outlet of the first heat exchanger 4, and the outlet of the heat storage tank 14 is connected to the hot side inlet of the second heat exchanger 9;

[0054] The seawater desalination circuit includes a thermal seawater desalination component 16, a fresh water tank 17 and a heat source device 18, the seawater inlet of which is connected to the cold side outlet of the condenser 5 and the cold side outlet of the cooler 11, the steam inlet of the thermal seawater desalination component 16 is connected to the outlet of the heat source device 18, the fresh water outlet of the thermal seawater desalination component 16 is connected to the fresh water tank 17, the brine outlet of the thermal seawater desalination component 16 is connected to the hot side inlet of the evaporator 8, and the condensate outlet of the thermal seawater desalination component 16 is connected to the inlet of the heat source device 18.

[0055] In one possible implementation, the specific implementation structure of the system consists of a carbon dioxide loop, a heat storage loop and a seawater desalination loop.

[0056] The carbon dioxide circuit consists of a low-pressure storage tank 1, a compressor 3, a first heat exchanger 4, a condenser 5, a high-pressure storage tank 6, an evaporator 8, a second heat exchanger 9, a turbine 10 and a cooler 11; the heat storage circuit consists of a cold storage tank 12 and a heat storage tank 14; the seawater desalination circuit consists of a thermal seawater desalination component 16, a fresh water tank 17 and a heat source device 18.

[0057] The low-pressure storage tank 1 is connected to the inlet of the compressor 3 through the low-pressure valve 2. The outlet of the compressor 3 is connected to the hot side inlet of the first heat exchanger 4. The hot side outlet of the first heat exchanger 4 is connected to the hot side inlet of the condenser 5. The hot side outlet of the condenser 5 is connected to the high-pressure storage tank 6.

[0058] The outlet of the high-pressure storage tank 6 is connected to the cold side inlet of the evaporator 8 through the high-pressure valve 7, the cold side outlet of the evaporator 8 is connected to the cold side inlet of the second heat exchanger 9, the cold side outlet of the second heat exchanger 9 is connected to the inlet of the turbine 10, the outlet of the turbine 10 is connected to the hot side inlet of the cooler 11, and the hot side outlet of the cooler 11 is connected to the low-pressure storage tank 1.

[0059] The outlet of the cold storage tank 12 is connected to the cold side inlet of the first heat exchanger 4 through a low-temperature pump 13, and the inlet of the cold storage tank 12 is connected to the hot side outlet of the second heat exchanger 9. The inlet of the heat storage tank 14 is connected to the cold side outlet of the first heat exchanger 4, and the outlet of the heat storage tank 14 is connected to the hot side inlet of the second heat exchanger 9 through a high-temperature pump 15.

[0060] The seawater inlet of the thermal seawater desalination component 16 is connected to the cold side outlet of the condenser 5 and the cold side outlet of the cooler 11, the steam inlet of the thermal seawater desalination component 16 is connected to the outlet of the heat source device 18, the fresh water outlet of the thermal seawater desalination component 16 is connected to the fresh water tank 17, the brine outlet of the thermal seawater desalination component 16 is connected to the hot side inlet of the evaporator 8, and the condensate outlet of the thermal seawater desalination component 16 is connected to the inlet of the heat source device 18.

[0061] It should be understood that, although the various steps in the flowcharts involved in the above-described embodiments are displayed in sequence according to the instructions, these steps are not necessarily executed in the order indicated. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the above-described embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0062] Corresponding to the aforementioned embodiment of the hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage, the present application also provides an embodiment of a method for operating the hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage using the system.

[0063] Figure 2 This is a schematic diagram of the energy storage process of a hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage, shown in an embodiment of the present application. Figure 3 This is a schematic diagram of the energy release process of a hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage, as shown in an embodiment of the present application.

[0064] In an exemplary embodiment, a method for a hydropower cogeneration system based on compressed carbon dioxide energy storage and thermal seawater desalination is provided. Renewable energy sources such as wind and solar power provide energy for the system. The compressed carbon dioxide energy storage system can smooth out fluctuations in the output power of renewable energy. By combining the seawater desalination system, the energy storage efficiency is improved and thermal pollution to the environment is reduced. The method of the system is divided into an energy storage process and an energy release process.

[0065] like Figure 2 As shown, the energy storage process includes:

[0066] The low-pressure carbon dioxide flows out of the low-pressure storage tank 1, is compressed by the compressor 3, enters the first heat exchanger 4 for cooling, and then is liquefied in the condenser. The liquid carbon dioxide is stored in the high-pressure storage tank. The compressor 3 is driven by the motor 19 generated by renewable energy.

[0067] At the same time, the heat storage medium is controlled to flow out of the cold storage tank 12 and enter the first heat exchanger 4 to absorb heat, and then the heated heat storage medium is stored in the heat storage tank 14;

[0068] At the same time, seawater is controlled to flow into the cold side inlet of the condenser 5, and after absorbing heat, it enters the thermal desalination component 16. The steam generated by the heat source device 18 drives the thermal desalination component 16 to desalinate the seawater at the outlet of the condenser 5. The driven steam condenses and then re-enters the heat source device 18. The generated fresh water is stored in the fresh water tank 17, and the generated high-concentration brine enters the evaporator 8 to release heat, completing the energy storage process.

[0069] like Figure 3 As shown, the energy release process includes:

[0070] The high-pressure liquid carbon dioxide flows into the evaporator 8 to absorb heat and become gaseous, then enters the second heat exchanger 9 to absorb heat and increase temperature, and then enters the turbine 10 to expand and produce work. The turbine 10 drives the generator 20 to generate electricity and transmit it to the power grid. The carbon dioxide at the outlet of the turbine 10 enters the cooler 11 to be cooled and stored in the low-pressure storage tank 1.

[0071] At the same time, the heat storage medium is controlled to flow out of the heat storage tank 14 and enter the hot side inlet of the second heat exchanger 9, and the heat storage medium that releases heat is stored in the cold storage tank 12;

[0072] At the same time, the seawater is controlled to flow into the cold side inlet of the cooler 11, and enters the thermal seawater desalination component 16 after absorbing heat. The steam generated by the heat source device 18 drives the thermal seawater desalination component 16 to desalinate the seawater at the outlet of the cooler 11. The driven steam condenses and then re-enters the heat source device 18. The generated fresh water is stored in the fresh water tank 17, and the generated high-concentration brine enters the evaporator 8 to release heat, completing the energy release process.

[0073] Among them, the outlet of the low-pressure storage tank 1 and the outlet of the high-pressure storage tank 6 are both provided with valves to control the outflow and flow of the liquid in the liquid storage tank; the outlet of the cold storage tank 12 and the outlet of the heat storage tank 14 are both provided with circulating pumps to control the outflow and flow of the heat storage medium; the outside of the low-pressure storage tank 1, the high-pressure storage tank 6, the cold storage tank 12 and the heat storage tank 14 are provided with an insulation layer; the carbon dioxide at the outlet of the condenser 5 is liquid, and the carbon dioxide at the outlet of the evaporator 8 is gaseous; the thermal seawater desalination component 16 can adopt multi-stage flash evaporation technology and multi-effect evaporation technology; the condenser 5 and the evaporator 8 can adopt a heat storage heat exchanger; the compression module consists of a single-stage or multi-stage compression process, and the expansion module consists of a single-stage or multi-stage expansion process.

[0074] It can be seen that the hydropower cogeneration system and method provided by the present invention for improving the gas-liquid conversion efficiency of compressed energy storage, by adopting renewable energy sources such as wind energy and solar energy as input and carbon dioxide as the energy storage working fluid, converts unstable wind energy and solar energy into the pressure potential energy and internal energy of the carbon dioxide working fluid through a compressor for storage, and stably releases the stored energy through a turbine when needed.

[0075] At the same time, by using the waste heat from the carbon dioxide energy storage system to preheat seawater, the heat loss caused by the large amount of heat dissipation in the liquefaction process is reduced, the heat consumption of the thermal seawater desalination system is reduced, and the fresh water production is increased.

[0076] At the same time, the heat of high-temperature brine generated by the thermal seawater desalination system is used to realize the gasification of the carbon dioxide energy storage system, which reduces the heat demand of the working fluid in the energy release process on the heat storage circuit, reduces the heat loss in the gasification process, and improves the efficiency of the energy storage system.

[0077] At the same time, the heat of the high-temperature brine is consumed by the energy storage system, reducing the brine discharge temperature to close to the ambient temperature, reducing the impact on the ecological environment.

[0078] The system has the advantages of high energy storage efficiency, low energy consumption for seawater desalination, and low pollution. It can effectively reduce the phenomenon of "wind abandonment" and "solar abandonment" and realize the efficient absorption of renewable energy.

[0079] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0080] The embodiments described above merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage, characterized in that: Including carbon dioxide circuit, heat storage circuit and seawater desalination circuit; The carbon dioxide circuit includes a low-pressure storage tank, a compressor, a first heat exchanger, a condenser, a high-pressure storage tank, an evaporator, a second heat exchanger, a turbine and a cooler connected in series; The heat storage circuit includes a cold storage tank and a heat storage tank, the cold storage tank outlet is connected to the cold side inlet of the first heat exchanger, the cold storage tank inlet is connected to the hot side outlet of the second heat exchanger, the heat storage tank inlet is connected to the cold side outlet of the first heat exchanger, and the heat storage tank outlet is connected to the hot side inlet of the second heat exchanger; The seawater desalination circuit includes a thermal seawater desalination component, a fresh water tank and a heat source device, wherein the seawater inlet is connected to the cold side outlet of the condenser and the cold side outlet of the cooler, the steam inlet of the thermal seawater desalination component is connected to the outlet of the heat source device, the fresh water outlet of the thermal seawater desalination component is connected to the fresh water tank, the brine outlet of the thermal seawater desalination component is connected to the hot side inlet of the evaporator, and the condensate outlet of the thermal seawater desalination component is connected to the inlet of the heat source device.

2. The hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage according to claim 1, characterized in that: The outlet of the low-pressure storage tank is provided with a low-pressure valve, and the outlet of the high-pressure storage tank is provided with a high-pressure valve.

3. The hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage according to claim 1, characterized in that: A low-temperature circulation pump is provided at the outlet of the cold storage tank, and a high-temperature circulation pump is provided at the outlet of the heat storage tank.

4. The hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage according to claim 1, characterized in that: The outer sides of the low-pressure storage tank, the high-pressure storage tank, the cold storage tank and the heat storage tank are all provided with insulation layers.

5. The hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage according to claim 1, characterized in that: The carbon dioxide discharged from the condenser outlet is in liquid state, and the carbon dioxide discharged from the evaporator outlet is in gaseous state.

6. The hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage according to claim 1, characterized in that: The thermal seawater desalination component adopts multi-stage flash evaporation technology or multi-effect evaporation technology.

7. The hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage according to claim 1, characterized in that: The condenser and evaporator adopt heat storage type heat exchangers.

8. The hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage according to claim 1, characterized in that: The compression module is composed of a single-stage or multi-stage compression process, and the expansion module is composed of a single-stage or multi-stage expansion process.

9. The hydropower cogeneration system for improving the gas-liquid conversion efficiency of compressed energy storage according to claim 1, characterized in that: The compressor is connected to an electric motor for driving, and the turbine is connected to a generator.

10. A method for improving the gas-liquid conversion efficiency of compressed energy storage in a water and power cogeneration system, characterized in that: Including energy storage process and energy release process; The energy storage process includes: The low-pressure carbon dioxide flows out of the low-pressure storage tank, is compressed by the compressor, and enters the first heat exchanger for cooling, and then is liquefied in the condenser. The liquid carbon dioxide is stored in the high-pressure storage tank. The compressor is driven by a motor generated by renewable energy; At the same time, the heat storage medium is controlled to flow out of the cold storage tank and enter the first heat exchanger to absorb heat, and then the heated heat storage medium is stored in the heat storage tank; At the same time, seawater is controlled to flow into the cold side inlet of the condenser. After absorbing heat and heating up, it enters the seawater desalination component. The steam generated by the heat source equipment drives the thermal seawater desalination component to desalinate the seawater at the condenser outlet. The steam condenses and then re-enters the heat source equipment. The generated fresh water is stored in the fresh water tank. The generated high-concentration brine enters the evaporator to release heat, completing the energy storage process. The energy release process includes: The high-pressure liquid carbon dioxide flows into the evaporator to absorb heat and turn into gas, then enters the second heat exchanger to absorb heat and increase temperature, and then enters the turbine to expand and produce work. The turbine drives the generator to generate electricity and transmit it to the power grid. The carbon dioxide at the turbine outlet enters the cooler to be cooled and stored in a low-pressure storage tank. At the same time, the heat storage medium is controlled to flow out of the heat storage tank and enter the hot side inlet of the second heat exchanger, and the heat storage medium that releases heat is stored in the cold storage tank; At the same time, the seawater is controlled to flow into the cold side inlet of the cooler, and enters the seawater desalination component after absorbing heat and heating up. The steam generated by the heat source equipment drives the thermal seawater desalination component to desalinate the seawater at the cooler outlet, and drives the steam to condense and then re-enter the heat source equipment. The generated fresh water is stored in the fresh water tank, and the generated high-concentration brine enters the evaporator to release heat, completing the energy release process.

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