Rankine cycle driving-based energy storage and seawater desalination system and method

Abstract

The invention provides an energy storage and sea water desalination system and method based on Rankine cycle driving. The system comprises a solar heat collection subsystem, an energy storage subsystem and a seawater desalination subsystem, wherein the solar heat collection subsystem converts solar energy into heat energy of a heat-conducting medium; the compressed gas energy storage subsystem is used for converting power grid electric energy into gas heat energy and storing the gas heat energy during energy storage, absorbing heat energy of a heat-conducting medium into gas heat energy during energy release, and converting the gas heat energy and the stored gas heat energy into external power grid electric energy; an organic working medium of the organic Rankine cycle subsystem absorbs the gas heat energy of the compressed gas energy storage subsystem and converts the gas heat energy into electric energy during energy storage, and absorbs the gas heat energy of the compressed gas energy storage subsystem to preheat seawater during energy release; according to the system, the electric energy of the power grid is converted into gas heat energy to be stored at the power utilization low peak, the stored gas heat energy is utilized to generate power at the power utilization peak, and the peak regulation effect is achieved; and the waste heat of the stored energy is used for driving the organic Rankine cycle subsystem to supply energy to the seawater desalination subsystem.

Description

Technical Field

[0001] The present invention relates to the technical field of sustainable energy development, and in particular to a Rankine cycle-driven energy storage and seawater desalination system and method. Background Art

[0002] In recent years, my country has been accelerating the planning and construction of a new energy system, actively promoting a green and low-carbon energy transition, and striving to elevate the development of renewable energy to a new level. Currently, my country's installed renewable energy capacity has exceeded 1.5 billion kilowatts. This rapid growth in installed renewable energy generation capacity has also significantly impacted the smooth operation of the power grid, leading to a rapidly increasing demand for new energy storage and other regulating resources.

[0003] Existing energy storage technologies primarily utilize pumped hydro, compressed air, and battery storage. Pumped hydro, constrained by geographical conditions, offers limited flexibility and negative environmental impacts. Battery energy storage primarily includes flow batteries, lead-acid batteries, and sodium-ion batteries. While battery storage offers advantages in terms of rapid response, it still leaves much room for improvement in safety, low-temperature performance, cycle life, initial investment, and maintenance costs. Compressed air storage offers greater flexibility but lower energy density and system operating efficiency. Meanwhile, desalination technologies, primarily thermal treatment and reverse osmosis membrane technologies, are widely deployed globally. Due to their high energy consumption and initial investment, thermal treatment currently accounts for a relatively low share of the global desalinated water market. Reverse osmosis membrane technology, on the other hand, offers relatively low energy consumption and ease of operation. However, traditional reverse osmosis membrane desalination systems rely directly on grid power, consuming significant amounts of high-quality electricity. Summary of the Invention

[0004] The present invention is made to solve the above problems, and its purpose is to provide an energy storage and seawater desalination system and method based on Rankine cycle drive.

[0005] The present invention provides an energy storage and seawater desalination system driven by a Rankine cycle, which has the following characteristics: a solar thermal collection subsystem, which is used to convert solar energy into thermal energy of a heat-conducting medium; a compressed gas energy storage subsystem, which is connected to the solar thermal collection subsystem and is used to convert external grid electrical energy into gas thermal energy and store it during energy storage, and is used to absorb the thermal energy of the heat-conducting medium into gas thermal energy during energy release, and convert it into external grid electrical energy together with the stored gas thermal energy; an organic Rankine cycle subsystem, which is connected to the compressed gas energy storage subsystem and is used to enable an organic working fluid to absorb the gas thermal energy of the compressed gas energy storage subsystem and convert it into electrical energy during energy storage, and is used to absorb the gas thermal energy of the compressed gas energy storage subsystem to preheat seawater during energy release; and a seawater desalination subsystem, which is connected to the organic Rankine cycle subsystem and is used to utilize the electrical energy generated by the organic Rankine cycle subsystem and the preheated seawater for seawater desalination.

[0006] The energy storage and seawater desalination system based on Rankine cycle drive provided by the present invention may also have the following features: wherein, the solar thermal collection subsystem includes: a solar thermal collector, used to convert solar energy into thermal energy of a heat-conducting medium; a first storage tank, connected to the solar thermal collector, used to store the heat-conducting medium after heat collection; a first liquid pump, connected to the first storage tank, used to transport the heat-conducting medium after heat collection; a second storage tank, used to store the heat-conducting medium after heat exchange; and a second liquid pump, connected to the second storage tank, used to transport the heat-conducting medium after heat exchange to the solar thermal collector.

[0007] The Rankine cycle-driven energy storage and seawater desalination system provided by the present invention may also have the following features: wherein the compressed gas energy storage subsystem includes: a third storage tank for storing gas; a compressor connected to the third storage tank for compressing the gas in the third storage tank; a first cooler connected to the compressor for transferring heat from the compressed gas to the organic Rankine cycle subsystem; a fourth storage tank connected to the first cooler for storing gas after transferring heat to the first cooler; a regenerator connected to the fourth storage tank for performing heat exchange with the gas in the fourth storage tank; a heater connected to the first liquid pump, the second storage tank, and the regenerator, respectively, for transferring heat from the heat transfer medium delivered by the first liquid pump to the gas from the regenerator, and then delivering the heat transfer medium back to the second storage tank after the heat transfer; a first turbine connected to the regenerator and the heater, respectively, for generating electricity using the gas in the heater, and delivering the gas after the work to the regenerator for heat exchange with the gas in the fourth storage tank; and a second cooler connected to the regenerator for transferring heat from the gas in the regenerator to the organic Rankine cycle subsystem.

[0008] The Rankine cycle-driven energy storage and seawater desalination system provided by the present invention may also have the following feature: the compressor and the first turbine are both connected to an external power grid.

[0009] The Rankine cycle-driven energy storage and seawater desalination system provided by the present invention may also have the following features: the organic Rankine cycle subsystem includes: a first booster pump, connected to the first cooler and the second cooler, respectively, for pumping the organic working fluid into the first cooler and the second cooler to absorb heat; a second turbine, connected to the first cooler, the second cooler and the seawater desalination subsystem, respectively, for using the organic working fluid after absorbing heat to generate electricity and supply power to the seawater desalination subsystem; a condenser, connected to the second turbine, the first booster pump and the seawater desalination subsystem, respectively, for using seawater to cool the organic working fluid and preheat the seawater; and a seawater pump, connected to the condenser, for pumping seawater into the condenser.

[0010] The energy storage and seawater desalination system based on Rankine cycle drive provided by the present invention may also have the following features: wherein the seawater desalination subsystem includes: a seawater storage tank, connected to the condenser, for storing preheated seawater; a first high-pressure pump, connected to the second turbine and the seawater storage tank, powered by the second turbine, for pressurizing the seawater in the seawater storage tank to a target pressure and then pumping it out; a first RO module, connected to the first high-pressure pump, for desalinating the pumped seawater through a reverse osmosis membrane to obtain first desalinated water and concentrated brine; an energy recovery module, connected to the seawater storage tank and the first RO module, for converting the pressure energy of the concentrated brine into the pressure energy of the seawater in the seawater storage tank; a second booster pump, connected to the second turbine and the seawater storage tank, powered by the second turbine, for pressurizing the seawater in the seawater storage tank to a target pressure and then pumping it out; a first RO module, connected to the first high-pressure pump, for desalinating the pumped seawater through a reverse osmosis membrane to obtain first desalinated water and concentrated brine; an energy recovery module, connected to the seawater storage tank and the first RO module, for converting the pressure energy of the concentrated brine into the pressure energy of the seawater in the seawater storage tank; and a second booster pump, connected to the second turbine and the seawater storage tank, powered by the second turbine, for pressurizing the seawater in the seawater storage tank to a target pressure and then pumping it out. The first RO module is connected to the energy recovery module and is used to pressurize the seawater in the energy recovery module to a target pressure, and then the seawater enters the first RO module together with the seawater in the first high-pressure pump for desalination; the first-level fresh water tank is connected to the first RO module and is used to store the first desalinated water; the second high-pressure pump is connected to the second turbine and the first-level fresh water tank, respectively, and is powered by the second turbine to pressurize the first desalinated water in the first-level fresh water tank and pump it out; the second RO module is connected to the first high-pressure pump and the second high-pressure pump, respectively, to desalinate the first desalinated water through a reverse osmosis membrane to obtain second desalinated water and concentrated brine, and then input the concentrated brine into the first high-pressure pump; the second-level fresh water tank is connected to the second RO module and is used to store the second desalinated water.

[0011] The Rankine cycle-driven energy storage and seawater desalination system provided by the present invention may also have the following feature: wherein the target pressure value is greater than or equal to 6 MPa.

[0012] The energy storage and seawater desalination system based on Rankine cycle drive provided by the present invention may also have the following feature: the gas is carbon dioxide.

[0013] A method for energy storage and seawater desalination based on Rankine cycle drive has the following characteristics: in the energy storage stage, the second liquid pump in the solar thermal collection subsystem pumps the heat transfer medium in the second storage tank into the solar thermal collector, the solar thermal collector converts solar energy into thermal energy of the heat transfer medium, and stores the collected heat transfer medium in the first storage tank, the compressor in the compressed gas energy storage subsystem uses external power grid to compress the gas in the third storage tank and transport it to the first cooler, the first cooler transfers the heat of the compressed gas to the organic Rankine cycle subsystem, and then stores the gas after heat transfer in the fourth storage tank, the organic Rankine cycle subsystem The first booster pump in the system pumps the organic working fluid into the first cooler to absorb heat. After absorbing heat, the organic working fluid enters the second turbine to generate power. In the energy release stage, the first liquid pump in the solar thermal collection subsystem pumps the heat-conducting medium after heat collection in the first storage tank to the heater to exchange heat with the gas therein. The heat-conducting medium after heat exchange enters the second storage tank from the heater. The gas in the fourth storage tank in the compressed gas energy storage subsystem enters the regenerator and then continues to enter the heater to exchange heat with the heat-conducting medium. After the gas reaches the target temperature, it enters the first turbine to generate power. The electricity generated by the first turbine is input into the external power grid. After the first turbine works The gas enters the regenerator, exchanges heat with the gas from the fourth storage tank, and then enters the second cooler. After heat exchange with the organic Rankine cycle subsystem in the second cooler, it flows into the third storage tank. The first booster pump in the organic Rankine cycle subsystem pumps the organic working fluid into the second cooler for heat exchange and then enters the second turbine to generate power to power the seawater desalination subsystem. The organic working fluid after working enters the condenser to preheat the seawater pumped into the condenser by the seawater pump. Then the organic working fluid enters the first booster pump to complete the cycle. The seawater storage tank in the seawater desalination subsystem stores the preheated seawater in the condenser. The first high-pressure pump pumps the seawater storage tank The seawater in the tank is pressurized to the target pressure and then pumped out. The first RO module desalinates the pumped seawater through a reverse osmosis membrane to obtain first desalinated water and concentrated brine. The energy recovery module converts the pressure energy of the concentrated brine into the pressure energy of seawater in the seawater storage tank and then discharges the concentrated seawater. The second booster pump pressurizes the seawater in the energy recovery module to the target pressure, and then the seawater enters the first RO module together with the seawater in the first high-pressure pump for desalination. The first desalinated water flows into the primary fresh water tank. The second high-pressure pump pumps the first desalinated water to the second RO module for further desalination through a reverse osmosis membrane to obtain second desalinated water. The second desalinated water flows into the secondary fresh water tank for storage.

[0014] Functions and effects of the invention

[0015] The energy storage and seawater desalination system and method based on Rankine cycle drive according to the present invention include: a solar thermal collection subsystem for converting solar energy into thermal energy of a heat-conducting medium; a compressed gas energy storage subsystem connected to the solar thermal collection subsystem for converting external grid electricity into gas thermal energy and storing it during energy storage, and for absorbing the thermal energy of the heat-conducting medium into gas thermal energy during energy release, and converting it into external grid electricity together with the stored gas thermal energy; an organic Rankine cycle subsystem connected to the compressed gas energy storage subsystem for allowing the organic working fluid to absorb the gas thermal energy of the compressed gas energy storage subsystem during energy storage. And converted into electrical energy, which is used to absorb the gas thermal energy of the compressed gas energy storage subsystem to preheat seawater when releasing energy; the seawater desalination subsystem is connected to the organic Rankine cycle subsystem, and is used to use the electrical energy generated by the organic Rankine cycle subsystem and the preheated seawater to desalinate seawater. Therefore, the energy storage and seawater desalination system and method based on Rankine cycle drive of the present invention converts external grid electrical energy into gas thermal energy and stores it during low-peak electricity consumption, and uses the stored gas thermal energy to generate electricity during peak electricity consumption, which plays a peak-shaving role in the power grid, and uses the waste heat energy of the stored energy to drive the organic Rankine cycle subsystem to supply energy to the seawater desalination subsystem, thereby realizing seawater desalination. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the structure of the energy storage and seawater desalination system based on Rankine cycle drive in an embodiment of the present invention.

[0017] Figure 2 Schematic diagram of the structure of the seawater desalination subsystem in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0019] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the following embodiments and accompanying drawings specifically illustrate the energy storage and seawater desalination system and method based on Rankine cycle drive of the present invention.

[0020] Example

[0021] Figure 1 Schematic diagram of the structure of the energy storage and seawater desalination system based on Rankine cycle drive in an embodiment of the present invention.

[0022] like Figure 1 As shown, this embodiment provides a Rankine cycle-driven energy storage and seawater desalination system 100, including: a solar thermal collection subsystem 1, a compressed gas energy storage subsystem 2, an organic Rankine cycle subsystem 3 and a seawater desalination subsystem 4.

[0023] The solar heat collection subsystem 1 is used to convert solar energy into thermal energy of a heat-conducting medium.

[0024] The solar heat collection subsystem 1 includes: a solar heat collector 10 , a first storage tank 11 , and a first liquid pump 12 .

[0025] The solar thermal collector 10 is used to convert solar energy into thermal energy of a heat transfer medium.

[0026] The first storage tank 11 is connected to the solar thermal collector 10 and is used to store the heat-conducting medium after heat collection.

[0027] The first liquid pump 12 is connected to the first storage tank 11 and is used to transport the heat-conducting medium after heat collection.

[0028] The second storage tank 13 is used to store the heat transfer medium after heat exchange.

[0029] The second liquid pump 14 is connected to the second storage tank 13 and is used to transport the heat-conducting medium after heat exchange to the solar thermal collector 10 .

[0030] The compressed gas energy storage subsystem 2 is connected to the solar thermal collection subsystem 1. During energy storage, it converts external grid electricity into gas thermal energy and stores it. During energy release, it absorbs the thermal energy of the heat transfer medium as gas thermal energy and converts it, along with the stored gas thermal energy, into external grid electricity. In this embodiment, the gas is carbon dioxide.

[0031] The compressed gas energy storage subsystem 2 includes: a third storage tank 20 , a compressor 21 , a first cooler 22 , a fourth storage tank 23 , a regenerator 24 , a heater 25 , a first turbine 26 , and a second cooler 27 .

[0032] The third storage tank 20 is used to store gas.

[0033] The compressor 21 is connected to the third storage tank 20 and is used to compress the gas in the third storage tank 20 .

[0034] The first cooler 22 is connected to the compressor 21 and is used to transfer the heat of the compressed gas to the organic Rankine cycle subsystem 3 .

[0035] The fourth storage tank 23 is connected to the first cooler 22 and is used to store the gas after transferring heat to the first cooler 22 .

[0036] The regenerator 24 is connected to the fourth storage tank 23 and is used to perform heat exchange using the gas in the fourth storage tank 23 .

[0037] The heater 25 is connected to the first liquid pump 12, the second storage tank 13 and the regenerator 24 respectively, and is used to transfer the heat of the heat-conducting medium transported by the first liquid pump 12 to the gas from the regenerator 24, and then transport the heat-conducting medium after heat transfer back to the second storage tank 13.

[0038] The first turbine 26 is connected to the regenerator 24 and the heater 25, respectively, and is configured to generate electricity by using the gas in the heater 25. The generated gas is then transported to the regenerator 24 for heat exchange with the gas in the fourth storage tank 23. The compressor 21 and the first turbine 26 are both connected to the external power grid.

[0039] The second cooler 27 is connected to the regenerator 24 and is used to transfer the gas heat in the regenerator 24 to the organic Rankine cycle subsystem 3 .

[0040] The organic Rankine cycle subsystem 3 is connected to the compressed gas energy storage subsystem 2. During energy storage, the organic working fluid absorbs the gas thermal energy of the compressed gas energy storage subsystem 2 and converts it into electrical energy. During energy release, the organic working fluid absorbs the gas thermal energy of the compressed gas energy storage subsystem 2 to preheat seawater.

[0041] The organic Rankine cycle subsystem 3 includes a first booster pump 30 , a second turbine 31 , a condenser 32 and a seawater pump 33 .

[0042] The first booster pump 30 is connected to the first cooler 22 and the second cooler 27 respectively, and is used to pump the organic working medium into the first cooler 22 and the second cooler 27 to absorb heat.

[0043] The second turbine 31 is connected to the first cooler 22 , the second cooler 27 and the seawater desalination subsystem 4 respectively, and is used to generate electricity by utilizing the organic working fluid after absorbing heat to supply power to the seawater desalination subsystem 4 .

[0044] The condenser 32 is connected to the second turbine 31 , the first booster pump 30 and the seawater desalination subsystem 4 respectively, and is used to cool the organic working medium and preheat the seawater using seawater.

[0045] The seawater pump 33 is connected to the condenser 32 and is used to pump seawater into the condenser 32 .

[0046] Figure 2 Schematic diagram of the structure of the seawater desalination subsystem in an embodiment of the present invention.

[0047] like Figure 2As shown, in this embodiment, the seawater desalination subsystem 4 is connected to the organic Rankine cycle subsystem 3 and is used to utilize the electrical energy generated by the organic Rankine cycle subsystem 3 and preheated seawater to perform seawater desalination.

[0048] The seawater desalination subsystem 4 includes: a seawater storage tank 40, a first high-pressure pump 41, a first RO module 42, an energy recovery module 43, a second booster pump 44, a primary fresh water tank 45, a second high-pressure pump 46, a second RO module 47, and a secondary fresh water tank 48.

[0049] The seawater storage tank 40 is connected to the condenser 32 and is used to store preheated seawater.

[0050] In this embodiment, the seawater storage tank 40 may also be replaced by a seawater pretreatment device for performing preliminary filtration, dosing, and other treatments on the seawater.

[0051] The first high-pressure pump 41 is connected to the second turbine 31 and the seawater storage tank 40 respectively, and is powered by the second turbine 31 to pressurize the seawater in the seawater storage tank 40 to a target pressure before pumping it out. The target pressure is greater than or equal to 6 MPa.

[0052] The first RO module 42 is connected to the first high-pressure pump 41 and is used to desalinate the pumped seawater through a reverse osmosis membrane, producing first desalinated water and concentrated brine. The RO module (reverse osmosis device) is a reverse osmosis device that uses membrane separation technology to remove charged ions, inorganic matter, colloidal particles, bacteria, and organic matter from water.

[0053] The energy recovery module 43 is connected to the seawater storage tank 40 and the first RO module 42 respectively. The seawater storage tank 40 is connected to the seawater side inlet of the energy recovery module 43, and the first RO module 42 is connected to the concentrated brine side inlet of the energy recovery module 43, which is used to convert the pressure energy of the concentrated brine into the pressure energy of the seawater in the seawater storage tank 40.

[0054] The second booster pump 44 is connected to the first RO module 42 and the energy recovery module 43 respectively, and is used to pressurize the seawater in the energy recovery module 43 to the target pressure, and then enter the first RO module 42 together with the seawater in the first high-pressure pump 41 for desalination.

[0055] The primary fresh water tank 45 is connected to the first RO module 42 and is used to store the first desalinated water.

[0056] The second high-pressure pump 46 is connected to the second turbine 31 and the first-stage fresh water tank 45 respectively, and is powered by the second turbine 31 to pressurize the first desalinated water in the first-stage fresh water tank 45 and pump it out.

[0057] The second RO module 47 is connected to the first high-pressure pump 41 and the second high-pressure pump 46 respectively, desalinates the first desalinated water through a reverse osmosis membrane to obtain second desalinated water and concentrated brine, and inputs the concentrated brine into the first high-pressure pump 41 .

[0058] The secondary fresh water tank 48 is connected to the second RO module 47 and is used to store the second desalinated water.

[0059] The second desalinated water is of drinking quality in this embodiment.

[0060] This embodiment also provides a Rankine cycle-driven energy storage and seawater desalination method, including:

[0061] During the energy storage stage, the second liquid pump 14 in the solar thermal collection subsystem 1 pumps the heat transfer medium in the second storage tank 13 into the solar thermal collector 10. The solar thermal collector 10 converts solar energy into thermal energy of the heat transfer medium and stores the collected heat transfer medium in the first storage tank 11. The compressor 21 in the compressed gas energy storage subsystem 2 uses power from the external power grid to compress the gas in the third storage tank 20 and transport it to the first cooler 22. The first cooler 22 transfers the heat of the compressed gas to the organic Rankine cycle subsystem 3 and stores the gas after heat transfer in the fourth storage tank 23. The first booster pump 30 in the organic Rankine cycle subsystem 3 pumps the organic working fluid into the first cooler 22 to absorb heat. After absorbing heat, the organic working fluid enters the second turbine 31 to perform work and generate electricity.

[0062] In the energy release stage, the first liquid pump 12 in the solar thermal collection subsystem pumps the collected heat-conducting medium in the first storage tank 11 into the heater 25 to perform heat exchange with the gas therein. The heat-conducting medium after heat exchange enters the second storage tank 13 from the heater 25. The gas in the fourth storage tank 23 in the compressed gas energy storage subsystem 2 enters the regenerator 24 and then continues to enter the heater 25 to perform heat exchange with the heat-conducting medium. After the gas reaches the target temperature, it enters the first turbine 26 to generate power. The electric energy generated by the first turbine 26 is input into the external power grid. The gas after the first turbine 26 performs work enters the regenerator. The organic working fluid enters the second cooler 27 after heat exchange with the gas from the fourth storage tank 23, and then flows into the third storage tank 20 after heat exchange with the organic Rankine cycle subsystem 3 in the second cooler 27. The first booster pump 30 in the organic Rankine cycle subsystem 3 pumps the organic working fluid into the second cooler 27 for heat exchange, and then enters the second turbine 31 to generate power to supply power to the seawater desalination subsystem 4. The organic working fluid after work enters the condenser 32 to preheat the seawater pumped into the condenser 32 by the seawater pump 33, and then the organic working fluid enters the first booster pump 30 to complete the cycle.

[0063] During the seawater desalination process, the seawater storage tank 40 in the seawater desalination subsystem 4 stores the preheated seawater in the condenser 32, the first high-pressure pump 41 pressurizes the seawater in the seawater storage tank 40 to the target pressure and then pumps it out, the first RO module 42 desalinates the pumped seawater through a reverse osmosis membrane to obtain first desalinated water and concentrated brine, the energy recovery module 43 converts the pressure energy of the concentrated brine into the pressure energy of the seawater in the seawater storage tank 40 and then discharges the concentrated seawater, the second booster pump 44 pressurizes the seawater in the energy recovery module to the target pressure, and then enters the first RO module 42 together with the seawater in the first high-pressure pump 41 for desalination, the first desalinated water flows into the primary fresh water tank 45, the second high-pressure pump 46 pumps the first desalinated water to the second RO module 47, further desalinates the first desalinated water through a reverse osmosis membrane, and obtains second desalinated water, which flows into the secondary fresh water tank 48 for storage.

[0064] Functions and Effects of the Embodiments

[0065] According to the energy storage and seawater desalination system and method based on Rankine cycle drive involved in this embodiment, it includes: a solar thermal collection subsystem for converting solar energy into thermal energy of a heat-conducting medium; a compressed gas energy storage subsystem connected to the solar thermal collection subsystem, which is used to convert external grid electricity into gas thermal energy and store it during energy storage, and is used to absorb the thermal energy of the heat-conducting medium into gas thermal energy during energy release, and convert it into external grid electricity together with the stored gas thermal energy; an organic Rankine cycle subsystem connected to the compressed gas energy storage subsystem, which is used to make the organic working fluid absorb the gas thermal energy of the compressed gas energy storage subsystem during energy storage. Energy is converted into electrical energy, which is used to absorb the gas thermal energy of the compressed gas energy storage subsystem to preheat seawater when releasing energy; the seawater desalination subsystem is connected to the organic Rankine cycle subsystem, and is used to use the electrical energy generated by the organic Rankine cycle subsystem and the preheated seawater to desalinate seawater. Therefore, the energy storage and seawater desalination system and method based on Rankine cycle drive of the present invention converts external grid electrical energy into gas thermal energy and stores it during low-peak electricity consumption, and uses the stored gas thermal energy to generate electricity during peak electricity consumption, thereby playing a peak-shaving role for the power grid, and uses the waste heat energy of the stored energy to drive the organic Rankine cycle subsystem to supply energy to the seawater desalination subsystem, thereby realizing seawater desalination.

[0066] This embodiment also absorbs solar energy through a solar thermal collector and transfers it to a heat-conducting medium.

[0067] This embodiment also transmits excess electrical energy in the power grid to the compressed high-temperature and high-pressure gas through the compressor.

[0068] This embodiment also realizes heat exchange between high-temperature and high-pressure gas and gas after work through a regenerator.

[0069] This embodiment also realizes heat exchange between the heat-conducting medium and the gas through a heater.

[0070] This embodiment also generates electricity by performing work through the first turbine and the second turbine.

[0071] This embodiment also uses a cooler to perform heat exchange between the gas and the organic working medium.

[0072] This embodiment also desalinates seawater through the reverse osmosis membrane of the RO module.

[0073] This embodiment also pressurizes the seawater by a booster pump.

[0074] This embodiment also converts the pressure energy of the concentrated brine into the pressure energy of seawater through the energy recovery module.

[0075] Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A Rankine cycle-driven energy storage and seawater desalination system connected to an external power grid for energy storage and power generation, characterized in that: include: A solar thermal collection subsystem for converting solar energy into thermal energy of a heat-conducting medium; A compressed gas energy storage subsystem is connected to the solar thermal collection subsystem and is used to convert external grid electricity into gas thermal energy and store it during energy storage. During energy release, it is used to absorb the thermal energy of the heat-conducting medium into gas thermal energy and convert it together with the stored gas thermal energy into external grid electricity. an organic Rankine cycle subsystem connected to the compressed gas energy storage subsystem, configured to allow the organic working medium to absorb the gas heat energy of the compressed gas energy storage subsystem and convert it into electrical energy during energy storage, and to absorb the gas heat energy of the compressed gas energy storage subsystem to preheat seawater during energy release; The seawater desalination subsystem is connected to the organic Rankine cycle subsystem and is used to desalinate seawater using the electric energy generated by the organic Rankine cycle subsystem and the preheated seawater.

2. The energy storage and seawater desalination system based on Rankine cycle drive according to claim 1, Its characteristics are: Wherein, the solar heat collection subsystem includes: a solar thermal collector for converting the solar energy into thermal energy of the heat-conducting medium; a first storage tank connected to the solar thermal collector and used to store the heat-conducting medium after heat collection; a first liquid pump connected to the first storage tank and used to transport the heat-conducting medium after heat collection; A second storage tank is used to store the heat transfer medium after heat exchange; The second liquid pump is connected to the second storage tank and is used to transport the heat-conducting medium after heat exchange to the solar thermal collector.

3. The energy storage and seawater desalination system based on Rankine cycle drive according to claim 2, Its characteristics are: Wherein, the compressed gas energy storage subsystem includes: a third storage tank for storing gas; a compressor connected to the third storage tank, for compressing the gas in the third storage tank; a first cooler connected to the compressor and configured to transfer heat from the compressed gas to the organic Rankine cycle subsystem; a fourth storage tank connected to the first cooler and configured to store the gas after transferring heat to the first cooler; a regenerator connected to the fourth storage tank and configured to utilize the gas in the fourth storage tank for heat exchange; a heater, connected to the first liquid pump, the second storage tank, and the regenerator, respectively, for transferring heat from the heat-conducting medium delivered by the first liquid pump to the gas from the regenerator, and then delivering the heat-conducting medium after heat transfer back to the second storage tank; The first turbine is connected to the regenerator and the heater respectively, and is used to generate electricity by using the gas in the heater, and to transport the gas after the work to the regenerator to exchange heat with the gas in the fourth storage tank. The second cooler is connected to the regenerator and is used to transfer the gas heat in the regenerator to the organic Rankine cycle subsystem.

4. The energy storage and seawater desalination system based on Rankine cycle drive according to claim 3 is characterized in that: in, The compressor and the first turbine are both connected to an external power grid.

5. The energy storage and seawater desalination system based on Rankine cycle drive according to claim 3, Its characteristics are: Wherein, the organic Rankine cycle subsystem includes: a first booster pump, connected to the first cooler and the second cooler, respectively, for pumping the organic working medium into the first cooler and the second cooler to absorb heat; a second turbine connected to the first cooler, the second cooler, and the seawater desalination subsystem, respectively, for utilizing the organic working fluid after absorbing heat to generate power to supply power to the seawater desalination subsystem; a condenser, connected to the second turbine, the first booster pump and the seawater desalination subsystem, respectively, for cooling the organic working medium and preheating the seawater using seawater; A seawater pump is connected to the condenser and is used to pump seawater into the condenser.

6. The energy storage and seawater desalination system based on Rankine cycle drive according to claim 5, Its characteristics are: Wherein, the seawater desalination subsystem includes: a seawater storage tank connected to the condenser and used to store preheated seawater; a first high-pressure pump, connected to the second turbine and the seawater storage tank, respectively, powered by the second turbine, and configured to pressurize the seawater in the seawater storage tank to a target pressure and then pump it out; a first RO module, connected to the first high-pressure pump, for desalinating the pumped seawater through a reverse osmosis membrane to obtain first desalinated water and concentrated brine; an energy recovery module, connected to the seawater storage tank and the first RO module, respectively, for converting the pressure energy of the concentrated brine into the pressure energy of the seawater in the seawater storage tank; a second booster pump, connected to the first RO module and the energy recovery module, respectively, for pressurizing the seawater in the energy recovery module to the target pressure and then feeding the seawater into the first RO module together with the seawater in the first high-pressure pump for desalination; a primary fresh water tank, connected to the first RO module, for storing first desalinated water; a second high-pressure pump, connected to the second turbine and the first-stage fresh water tank, respectively, powered by the second turbine, and configured to pressurize the first desalinated water in the first-stage fresh water tank and then pump it out; a second RO module, connected to the first high-pressure pump and the second high-pressure pump, respectively, desalinating the first desalinated water through a reverse osmosis membrane to obtain second desalinated water and concentrated brine, and inputting the concentrated brine into the first high-pressure pump; The secondary fresh water tank is connected to the second RO module and is used to store the second desalinated water.

7. The energy storage and seawater desalination system based on Rankine cycle drive according to claim 6 is characterized in that: in, The target pressure is greater than or equal to 6 MPa.

8. The Rankine cycle-driven energy storage and seawater desalination system according to any one of claims 1 to 7, characterized in that: in, The gas is carbon dioxide.

9. A method for energy storage and seawater desalination based on Rankine cycle drive, characterized in that: include: In the energy storage stage, the second liquid pump in the solar thermal collection subsystem pumps the heat transfer medium in the second storage tank into the solar thermal collector, and the solar thermal collector converts solar energy into thermal energy of the heat transfer medium, and stores the collected heat transfer medium in the first storage tank. The compressor in the compressed gas energy storage subsystem uses power from the external grid to compress the gas in the third storage tank and transport it to the first cooler. The first cooler transfers the heat of the compressed gas to the organic Rankine cycle subsystem and then stores the heat-transferred gas in the fourth storage tank. The first booster pump in the organic Rankine cycle subsystem pumps the organic working fluid into the first cooler to absorb heat. After absorbing the heat, the organic working fluid enters the second turbine to generate power. In the energy release stage, the first liquid pump in the solar thermal collection subsystem pumps the heat-conducting medium after heat collection in the first storage tank into the heater to perform heat exchange with the gas therein. The heat-conducting medium after heat exchange enters the second storage tank from the heater. The gas in the fourth storage tank of the compressed gas energy storage subsystem enters the regenerator and then continues to enter the heater to exchange heat with the heat transfer medium. After the gas reaches the target temperature, it enters the first turbine to generate power. The electricity generated by the first turbine is input into the external power grid. The gas after the first turbine has generated power enters the regenerator, exchanges heat with the gas from the fourth storage tank, and then enters the second cooler. In the second cooler, it exchanges heat with the organic Rankine cycle subsystem and then flows into the third storage tank. The first booster pump in the organic Rankine cycle subsystem pumps the organic working fluid into the second cooler for heat exchange, and then enters the second turbine to generate power to power the seawater desalination subsystem. The organic working fluid after working enters the condenser to preheat the seawater pumped into the condenser by the seawater pump, and then enters the first booster pump to complete the cycle. The seawater storage tank in the seawater desalination subsystem stores the seawater preheated in the condenser, the first high-pressure pump pressurizes the seawater in the seawater storage tank to a target pressure and then pumps it out, the first RO module desalinates the pumped seawater through a reverse osmosis membrane to obtain first desalinated water and concentrated brine, the energy recovery module converts the pressure energy of the concentrated brine into the pressure energy of the seawater in the seawater storage tank and then discharges the concentrated seawater, the second booster pump pressurizes the seawater in the energy recovery module to the target pressure, and then enters the first RO module together with the seawater in the first high-pressure pump for desalination, the first desalinated water flows into the primary fresh water tank, the second high-pressure pump pumps the first desalinated water to the second RO module to further desalinate the first desalinated water through a reverse osmosis membrane to obtain second desalinated water, and the second desalinated water flows into the secondary fresh water tank for storage.

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