Heat compensation type liquid carbon dioxide energy storage system and using method
Through the heat-supplementing liquid carbon dioxide energy storage system, using components such as phase change cold storage and heat-supplementing modules, the operating temperature and energy storage density of CO2 are improved, solving the problem of weak working capacity of CO2 during the charge and discharge cycle caused by the small pressure ratio of the liquid storage tank, and realizing efficient energy storage and power generation process.
Patent Information
- Application Number
- CN202511016940.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-23
- Publication Date
- 2025-10-17
AI Technical Summary
The existing liquid carbon dioxide energy storage system has a small pressure ratio between high- and low-pressure liquid storage tanks, resulting in weak work capacity per unit mass of CO2 during the charge and discharge cycle, and is unable to effectively improve the system's peak power generation capacity and operating flexibility.
A heat-supplementing liquid carbon dioxide energy storage system is adopted. By setting up a phase-change cold storage device, a heat-supplementing module, a preheating circulation unit, and a compression and heat recovery circulation unit, efficient storage and heat recovery of liquid carbon dioxide can be achieved, thereby improving the CO2 operating temperature and energy storage density.
It greatly improves the working capacity of CO2 per unit mass, enhances the system's peak power generation capacity and working flexibility, solves the problem of weak working capacity of CO2 during the charge and discharge cycle due to the small pressure ratio, and realizes efficient liquefaction storage under different ambient temperatures.
Smart Images
Figure CN120798484A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of novel energy storage technology, and in particular to a heat-supplementing liquid carbon dioxide energy storage system and a method of using the same. Background Art
[0002] Wind power and photovoltaic power generation are important components of renewable energy. However, these technologies exhibit significant volatility, periodicity, and uncertainty. Their large-scale grid integration not only poses challenges to grid stability but also results in significant energy waste. Therefore, developing large-scale, efficient energy storage systems has become a crucial task in power system development. To further improve the efficiency and energy density of energy storage systems, researchers have proposed carbon dioxide energy storage (CES) systems using CO2 as a working fluid. This is because CO2 has a more accessible critical point (7.39 MPa and 31.4°C) than air (3.77 MPa and -140.5°C), is non-toxic and non-flammable, and has an A1 safety rating. Under the same conditions and pressures, CO2 has a higher storage density than air, with the highest density when stored in liquid form. This gives CES systems significant energy storage potential.
[0003] Existing CES systems can be primarily categorized as adiabatic and non-adiabatic. Adiabatic CES systems recover the compression heat of CO2 during the energy storage process without introducing an external heat source, and then reuse the compression heat to heat the CO2 during the power generation process. Non-adiabatic CES systems, in addition to recycling the compression heat of CO2, also introduce an external heat source to increase the operating temperature of the CO2 power generation process or improve the temperature difference between CO2 heat exchangers, thereby improving the round-trip efficiency of the CES system's charge and discharge cycles. This external heat source can be industrial waste heat, nuclear heat release, or solar thermal energy.
[0004] For CES systems, LCES (liquid carbon dioxide energy storage) is a highly promising configuration. LCES utilizes the readily liquefiable nature of CO2, storing it in liquid form in both the high-pressure and low-pressure tanks of a closed-loop system. This eliminates the reliance on large storage spaces for compressed air energy storage and addresses the large footprint of the low-pressure storage tank in gas-liquid CES systems, significantly increasing the system's energy storage density. However, due to the physical limitations of CO2's triple point (-56.6°C, 5.11 atm), the operating pressure of the LCES's low-pressure tank is several times greater than atmospheric pressure. This significantly reduces the pressure ratio during the LCES system's charge / discharge cycle, significantly reducing the work capacity of CO2 per unit mass during the charge / discharge process. Clearly, an adiabatic configuration cannot address this CO2 work capacity issue for LCES systems.
[0005] Therefore, a liquid carbon dioxide energy storage system capable of improving the work capacity of unit mass CO2, improving the peak power generation capacity of the system, further improving the working flexibility of the system, and making up for the gap of power grid peak regulation is continued. SUMMARY
[0006] The purpose of the present application is to solve the above technical problems, provide a heat-supplementing liquid carbon dioxide energy storage system and use method, under the cooperation of a heat-supplementing module, a preheating circulating unit and a compression and heat recovery circulating unit,
[0007] The liquid carbon dioxide storage can be realized, the energy storage density and CO2 working temperature of the system are improved, and the problem of weak work capacity of unit mass CO2 in the charging and discharging cycle process caused by the small pressure ratio between the high-pressure and low-pressure liquid storage tanks is solved.
[0008] To achieve the above purpose, the present application provides the following scheme: the present application discloses a heat-supplementing liquid carbon dioxide energy storage system, comprising a low-pressure liquid storage tank (1), a phase change cold accumulator (3) and a high-pressure liquid storage tank (12);
[0009] The liquid outlet of the low-pressure liquid storage tank (1) is connected to the cold side of the phase change cold accumulator (3) through a low-temperature expansion valve (2), and the cold side of the phase change cold accumulator (3) and the liquid inlet of the high-pressure liquid storage tank (12) are sequentially connected in the airflow direction with an energy storage side preheater (4), a compression and heat recovery module and an energy storage side cooling module, the compression and heat recovery module comprises a compression and heat recovery assembly, the compression and heat recovery assembly comprises a compressor and an energy storage side heat collector arranged in series, and the compressor and the energy storage side heat collector are sequentially arranged in the airflow direction;
[0010] The liquid outlet of the high-pressure liquid storage tank (12) and the hot side of the phase change cold accumulator (3) are sequentially connected in the airflow direction with a booster pump (13), a power generation side regenerator (14), a heat-supplementing module, a turbine generator set (16), a power generation side cooling module and a power generation side heat collector (18), the hot side of the phase change cold accumulator (3) and the liquid inlet of the low-pressure liquid storage tank (1) are connected with a power generation side refrigeration module, the power generation side regenerator (14) and the energy storage side heat collector exchange cold and heat through a compression heat cycle hot tank (26) and a compression heat cycle cold tank (28), and the power generation side heat collector (18) and the energy storage side preheater (4) exchange cold and heat through a preheating cycle cold tank (20) and a preheating cycle hot tank (22).
[0011] Preferably, the energy storage side cooling module comprises an energy storage side air cooler (9), an energy storage side shunt valve (10), and an energy storage side water chiller (11), the air inlet end of the energy storage side air cooler (9) is connected with the compression and heat recovery module, the air outlet end of the energy storage side air cooler (9) is connected with a first shunt branch and a second shunt branch through the energy storage side shunt valve (10), the first shunt branch and the second shunt branch are both connected with the liquid inlet of the high-pressure liquid storage tank (12), and the heat exchanger of the energy storage side water chiller (11) is connected on the first shunt branch.
[0012] Preferably, the compression and heat recovery module comprises a plurality of compression and heat recovery assemblies arranged in series, the liquid inlet end of the energy storage side heat collector of the plurality of compression and heat recovery assemblies is connected with the compression heat cycle cold tank (28) through a compression heat cycle shunt valve (29) and a compression heat cycle cold side pump, the liquid outlet end of the energy storage side heat collector of the plurality of compression and heat recovery assemblies is connected with the compression heat cycle hot tank (26) through a compression heat cycle shunt valve (25), the compressor of the first-stage compression and heat recovery assembly is connected with the energy storage side preheater (4), and the energy storage side heat collector of the last-stage compression and heat recovery assembly is connected with the energy storage side cooling module.
[0013] Preferably, the power generation side cooling module comprises a power generation side air cooler (17).
[0014] Preferably, the power generation side refrigeration module comprises a power generation side low-temperature refrigeration unit (19), and the heat exchanger of the power generation side low-temperature refrigeration unit (19) is connected between the hot side of the phase change cold accumulator (3) and the liquid inlet of the low-pressure liquid storage tank (1).
[0015] Preferably, a preheating cycle cold side pump (21) is arranged between the preheating cycle cold tank (20) and the power generation side heat collector (18), and a preheating cycle hot side pump (23) is arranged between the preheating cycle hot tank (22) and the energy storage side preheater (4).
[0016] Preferably, the heat supplement module adopts a solar heat collecting device, the solar heat collecting device comprises a solar low-temperature heat conducting oil tank (31), a solar low-temperature heat conducting oil pump (32), a solar heat collector (33), a solar high-temperature heat conducting oil tank (34), a solar high-temperature heat conducting oil pump (35) and a solar heat conducting oil heat exchanger (15), a first heat exchange passage of the solar heat exchanger (36) is connected between the turbine generator set (16) and the power generation side regenerator (14), and a liquid outlet end of a second heat exchange passage of the solar heat exchanger (36) is connected to a liquid inlet end of the solar low-temperature heat conducting oil tank (31), the solar low-temperature heat conducting oil pump (32) and the solar heat collector (33) in sequence, and a liquid outlet end of the solar heat collector (33) is connected to a liquid inlet end of the solar high-temperature heat conducting oil tank (34), the solar high-temperature heat conducting oil pump (35) and the second heat exchange passage of the solar heat exchanger (36) in sequence.
[0017] The application further discloses a heat supplement type liquid carbon dioxide energy storage system and a use method thereof.
[0018] In the energy storage process, the liquid carbon dioxide in the low-pressure liquid storage tank (1) flows out, enters the low-temperature expansion valve (2) to reduce the pressure, the carbon dioxide flowing out of the low-temperature expansion valve (2) enters the cold side of the phase change cold accumulator (3) to absorb heat and release cold, and the cold is stored in the phase change cold accumulator (3) in the form of latent heat, and the liquid carbon dioxide is vaporized into gaseous carbon dioxide after absorbing heat, the gaseous carbon dioxide enters the energy storage side preheater (4) to exchange heat with the fluid flowing out of the preheating cycle hot tank (22) and absorb heat, the fluid cooled flows into the preheating cycle cold tank (20) and is stored, the gaseous carbon dioxide after preheating enters the compression and heat recovery module, is first pressurized and heated by the compressor, then exchanges heat with the fluid flowing out of the compression heat cycle cold tank (28) in the energy storage side heat collector and releases heat, the fluid after absorbing heat flows into the compression heat cycle hot tank (26) and is stored, and then the gaseous carbon dioxide is condensed into liquid carbon dioxide by the energy storage side cooling module, and finally the liquid carbon dioxide enters the high-pressure liquid storage tank (12) to complete the system energy storage process.
[0019] Power generation process: the liquid carbon dioxide in the high-pressure liquid storage tank (12) is pressurized by the booster pump (13), and the pressurized carbon dioxide enters the power generation side regenerator (14), exchanges heat with the fluid flowing out of the compression heat absorption circulation hot tank (26) and absorbs heat, and the cooled fluid flows into the compression heat circulation cold tank (28) for storage, and the carbon dioxide after absorbing heat absorbs heat again through the heat supplement module to increase the temperature of the supercritical carbon dioxide, and then expands and performs work in the turbine generator set (16), and the pressure and temperature of the carbon dioxide are reduced, and the carbon dioxide flows through the power generation side cooling module and enters the power generation side heat collector (18), exchanges heat with the fluid flowing out of the preheating circulation cold tank (20) and releases sensible heat, and the fluid after absorbing heat flows into the preheating circulation hot tank (22) for storage, and the cooled carbon dioxide flows into the hot side of the phase change cold storage (3), and the cold storage medium in the phase change cold storage (3) releases latent heat to liquefy the carbon dioxide, and finally is fully condensed by the power generation side refrigeration module and transported to the low-pressure liquid storage tank (1) for storage, and the system completes the discharge process.
[0020] Preferably, the method further comprises the following steps:
[0021] During the energy storage process: when the outside air temperature is high and the carbon dioxide cannot be liquefied after passing through the energy storage side air cooler (9), the energy storage side diverter valve (10) opens the first diverter branch and closes the second diverter branch, and all the carbon dioxide is fully condensed and liquefied by the energy storage side chiller (11) before entering the high-pressure liquid storage tank (12) for storage; when the outside air temperature is low and the carbon dioxide can be completely liquefied after passing through the energy storage side air cooler (9), the energy storage side diverter valve (10) opens the second diverter branch and closes the first diverter branch, and the carbon dioxide directly enters the high-pressure liquid storage tank (12) for storage.
[0022] Preferably, the method further comprises the following steps:
[0023] The working process of the solar heat collecting device is as follows: the high-temperature heat-conducting oil in the solar high-temperature heat-conducting oil tank (34) flows out and is transported to the solar heat-conducting oil heat exchanger (15) through the solar high-temperature heat-conducting oil pump (35) to heat the carbon dioxide, thereby increasing the temperature of the carbon dioxide before entering the turbine generator (16) group. The heat-conducting oil after heat exchange flows into the solar low-temperature heat-conducting oil tank (31) for storage. When there is sufficient sunlight, the heat-conducting oil in the solar low-temperature heat-conducting oil tank (31) flows out and is transported to the solar collector (33) through the solar low-temperature heat-conducting oil pump (32) to absorb solar energy. After heating, the heat-conducting oil is stored in the solar high-temperature heat-conducting oil tank (34) to complete the cycle.
[0024] Compared with the prior art, the present invention has achieved the following technical effects:
[0025] In the application, the phase change cold accumulator is arranged, the heat supplement module is arranged to supplement heat into the system, the energy storage side preheater, the preheating circulating cold tank, the preheating circulating hot tank and the power generation side heat collector are arranged to form a preheating circulating unit, the compression and heat recovery module (including a compressor and an energy storage side heat collector), the compression heat circulating hot tank, the compression heat circulating cold tank and the power generation side regenerator are arranged to form a compression and heat recovery circulating unit, the CO2 in the energy storage process is released from the low-pressure liquid storage tank, passes through the phase change cold accumulator, can fully absorb heat to be gasified, and the cold energy generated in the gasification process is stored in the phase change medium, the CO2 in the discharge process passes through the phase change cold accumulator, reabsorbs the cold energy stored in the phase change medium to be liquefied, greatly reduces the energy consumption of the low-pressure carbon dioxide liquefaction, and the heat supplement module supplements heat into the system in the discharge process, the heat can improve the working temperature of the CO2 before entering the generator set, and under the action of the preheating circulating unit, the working temperature of the CO2 before entering the compressor in the energy storage process is also improved, and under the action of the compression and heat recovery circulating unit, the working temperature of the CO2 flowing out of the high-pressure liquid storage tank in the discharge process is improved, so that the whole system realizes efficient heat recovery, the CO2 can work in a higher temperature range, the working capacity of the unit mass CO2 is improved, the peak power generation capacity of the system is improved, the working flexibility of the LCES system is further improved, the gap of the power grid peak regulation is made up, and the problem that the unit mass CO2 in the charging and discharging cycle process has weak work capacity due to the small pressure ratio between the high-pressure liquid storage tank and the low-pressure liquid storage tank is solved.
[0026] The other technical solutions of the application also have the following technical effects compared with the prior art:
[0027] 1. In the application, different cooling means are adapted to the environmental temperature, the liquefaction is cooled in summer through the refrigerating unit, and the liquefaction is cooled in winter through air, so that different scenes are efficiently liquefied and stored with low energy consumption.
[0028] 2. In the application, the compression and heat recovery module includes compression and heat recovery components arranged in multiple stages in series, each compression and heat recovery component includes a compressor and an energy storage side heat collector, the process of recovering compression heat is divided into multiple stages, interstage cooling is adopted, multiple compression heat flows are collected to heat the CO2 in the power generation process, and the heat exchange mismatch phenomenon caused by the pressure difference between the compression process and the energy storage process is solved.
[0029] 3. In the application, the heat supplement module uses solar light concentration heat collection, integrates solar heat supplement to realize the coupling of the energy storage system and renewable energy, increases the use scene of renewable energy, improves the stability of renewable energy output fluctuation, and the solar light concentration heat collection uses heat conduction oil to store light heat, the heat conduction oil indirectly heats the CO2, improves the working temperature of the CO2, improves the work capacity of the CO2, and solves the instability hidden danger of the system power generation caused by the uncertainty of light. BRIEF DESCRIPTION OF DRAWINGS
[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings described below only illustrate some of the embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor.
[0031] Fig. 1 Structure diagram of the heat-supplementing liquid carbon dioxide energy storage system in the embodiments of the present application;
[0032] Fig. 2 Winter working process diagram of the heat-supplementing liquid carbon dioxide energy storage system in the embodiments of the present application;
[0033] Fig. 3 Summer working process diagram of the heat-supplementing liquid carbon dioxide energy storage system in the embodiments of the present application.
[0034] Legend: 1, low-pressure liquid storage tank; 2, low-temperature expansion valve; 3, phase-change cold accumulator; 4, energy storage side preheater; 5, first compressor; 6, energy storage side first heat collector; 7, second compressor; 8, energy storage side second heat collector; 9, energy storage side air cooler; 10, energy storage side flow dividing valve; 11, energy storage side water chiller; 12, high-pressure liquid storage tank; 13, booster pump; 14, power generation side regenerator; 15, solar heat conducting oil heat exchanger; 16, turbine generator set; 17, power generation side air cooler; 18, power generation side heat collector; 19, power generation side low-temperature refrigeration unit; 20, preheating circulating cold tank; 21, preheating circulating cold side pump; 22, preheating circulating hot tank; 23, preheating circulating hot side pump; 24, compression heat circulating cold side first pump; 25, compression heat circulating flow combining valve; 26, compression heat circulating hot tank; 28, compression heat circulating cold tank; 29, compression heat circulating flow dividing valve; 30, compression heat circulating cold side second pump; 31, solar low-temperature heat conducting oil tank; 32, solar low-temperature heat conducting oil pump; 33, solar heat collector; 34, solar high-temperature heat conducting oil tank; 35, solar high-temperature heat conducting oil pump. DETAILED DESCRIPTION
[0035] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, and not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.
[0036] The purpose of the present invention is to provide a heat-supplementing liquid carbon dioxide energy storage system and a method of use to solve the problems existing in the prior art. With the cooperation of the liquid storage tank, the heat-supplementing module, the preheating circulation unit and the compression and heat recovery circulation unit, liquid carbon dioxide storage can be realized, the system energy storage density and CO2 operating temperature can be improved, the working capacity per unit mass of CO2 can be improved, and the problem of weak working capacity per unit mass of CO2 in the charge and discharge cycle process caused by the small pressure ratio between the high and low pressure liquid storage tanks can be solved.
[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.
[0038] Example 1
[0039] like Figs. 1 to 3 As shown, this embodiment provides a heat-compensating liquid carbon dioxide energy storage system, including a low-pressure liquid storage tank 1, a low-temperature expansion valve 2, a phase-change cold accumulator 3, an energy storage-side preheater 4, a compression and heat recovery module, an energy storage-side cooling module (see reference numerals 9, 10, and 11), a high-pressure liquid storage tank 12, a booster pump 13, a power generation-side regenerator 14, a heat-compensating module (see reference numerals 15, 31-35), a turbine generator set 16, a power generation-side cooling module (see reference numeral 17), a power generation-side heat collector 18, a power generation-side refrigeration module (see reference numeral 19), a preheating cycle cold tank 20, a preheating cycle hot tank 22, a compression heat cycle hot tank 26, and a compression heat cycle cold tank 28. The low-pressure liquid storage tank 1 and the high-pressure liquid storage tank 12 store low-pressure liquid carbon dioxide and high-pressure liquid carbon dioxide, respectively.
[0040] The outlet of the low-pressure liquid storage tank 1 is connected to the inlet of the cold side of the phase-change cold storage device 3 through the low-temperature expansion valve 2. The outlet of the cold side of the phase-change cold storage device 3 is connected to the inlet of the first heat exchange path of the energy storage side preheater 4, the outlet of the first heat exchange path of the energy storage side preheater 4 is connected to the inlet of the compression and heat recovery module, the outlet of the compression and heat recovery module is connected to the inlet of the energy storage side cooling module, and the outlet of the energy storage side cooling module is connected to the inlet of the high-pressure liquid storage tank 12. The compression and heat recovery module includes at least one stage of compression and heat recovery components, each stage of compression and heat recovery components includes a compressor and an energy storage side collector, wherein a compressor and an energy storage side collector are arranged in series, and the compressor and energy storage side collector in each stage of compression and heat recovery components are arranged sequentially along the airflow direction. The number of levels of compression and heat recovery components can be set as needed, such as setting a two-stage compression and heat recovery component, with specific reference to the setting methods of the first compressor 5 and the first collector 6 on the energy storage side and the second compressor 7 and the second collector 8 on the energy storage side.
[0041] The outlet end of the high-pressure liquid tank 12 is connected to the inlet end of the booster pump 13, the outlet end of the booster pump 13 is connected to the inlet end of the first heat exchange passage of the power generation side regenerator 14, the outlet end of the first heat exchange passage of the power generation side regenerator 14 is connected to the inlet end of the heat supplement module, the outlet end of the heat supplement module is connected to the inlet end of the turbine generator set 16, the outlet end of the turbine generator set 16 is connected to the inlet end of the hot side of the phase change cold accumulator 3, the outlet end of the hot side of the phase change cold accumulator 3 is connected to the inlet end of the power generation side refrigeration module, and the outlet end of the power generation side refrigeration module is connected to the inlet end of the low-pressure liquid tank 1. The inlet end of the second heat exchange passage of the power generation side regenerator 14 is connected to the outlet end of the second heat exchange passage of the energy storage side heat collector through the compression heat cycle hot tank 26, and the outlet end of the second heat exchange passage of the power generation side regenerator 14 is connected to the inlet end of the second heat exchange passage of the energy storage side heat collector through the compression heat cycle cold tank 28. The compression and heat recovery module, the compression heat cycle hot tank 26, the compression heat cycle cold tank 28 and the power generation side regenerator 14 form a compression and heat recovery cycle unit. The inlet end of the second heat exchange passage of the power generation side heat collector 18 is connected to the outlet end of the second heat exchange passage of the energy storage side preheater 4 through the preheating cycle cold tank 20, and the outlet end of the second heat exchange passage of the power generation side heat collector 18 is connected to the inlet end of the second heat exchange passage of the energy storage side preheater 4 through the preheating cycle hot tank 22. The energy storage side preheater 4 forms a preheating cycle unit between the power generation side heat collector 18, the preheating cycle cold tank 20 and the preheating cycle hot tank 22.
[0042] Working principle:
[0043] Energy storage process: after receiving the power grid energy storage scheduling instruction, the system operates in the energy storage mode, the liquid carbon dioxide in the low-pressure liquid tank 1 flows out, enters the low-temperature expansion valve 2 to reduce the pressure, the carbon dioxide flowing out of the low-temperature expansion valve 2 enters the cold side of the phase change cold accumulator 3 to absorb heat and release cold, and the cold is stored in the phase change cold accumulator 3 in the form of latent heat, and the liquid carbon dioxide vaporizes into gaseous carbon dioxide after absorbing heat. The gaseous carbon dioxide enters the energy storage side preheater 4, exchanges heat with the fluid flowing out of the preheating cycle hot tank 22 and absorbs heat, the cooled fluid flows into the preheating cycle cold tank 20 and is stored, the preheated gaseous carbon dioxide enters the compression and heat recovery module, is first pressurized and heated by the compressor, then exchanges heat with the fluid flowing out of the compression heat cycle cold tank 28 in the energy storage side heat collector and releases heat, the heated fluid flows into the compression heat cycle hot tank 26 for storage, and then the gaseous carbon dioxide is condensed into liquid carbon dioxide by the energy storage side cooling module. Finally, the liquid carbon dioxide enters the high-pressure liquid tank (12) to complete the system energy storage process;
[0044] Power generation process: after the system receives the power grid power generation scheduling instruction, the system runs in the power generation mode, the liquid carbon dioxide in the high-pressure liquid storage tank 12 is pressurized by the booster pump 13, the pressurized carbon dioxide enters the power generation side regenerator 14, exchanges heat with the fluid flowing out of the absorption compression heat cycle heat tank 26 and absorbs heat, the cooled fluid flows into the compression heat cycle cold tank 28 for storage, the heat-absorbed carbon dioxide absorbs heat again through the heat supplement module, the temperature of the supercritical carbon dioxide is increased, and then the supercritical carbon dioxide is expanded in the turbine generator set 16 to do work, the pressure and temperature of the carbon dioxide are reduced, the carbon dioxide flows through the power generation side cooling module, and then enters the power generation side collector 18, exchanges heat with the fluid flowing out of the preheating cycle cold tank 20 and releases sensible heat, the heat-absorbed fluid flows into the preheating cycle heat tank 22 for storage, and the cooled carbon dioxide flows into the hot side of the phase change cold storage device 3, the cold storage medium in the phase change cold storage device 3 releases latent heat to liquefy the carbon dioxide, and finally the carbon dioxide is fully condensed through the power generation side refrigeration module and then transported to the low-pressure liquid storage tank 1 for storage, and the system completes the power generation process.
[0045] The specific principle of the phase change cold storage device is as follows:
[0046] During the energy storage process of the system, the low-temperature expansion valve 2 is opened, the liquid carbon dioxide is released from the low-pressure liquid storage tank 1, part of the pressure is reduced through the low-temperature expansion valve 2, the saturation temperature is reduced, and the carbon dioxide enters the cold side of the phase change cold storage device 3 at a temperature lower than that of the cold storage medium in the phase change cold storage device 3. Through indirect heat exchange, the carbon dioxide absorbs heat and vaporizes, and the cold storage medium in the phase change cold storage device 3 releases heat and changes phase from near liquid state to near solid state. During the power generation process of the system, the gaseous carbon dioxide releases sensible heat through the power generation side collector 18, and then enters the hot side of the phase change cold storage device 3 after the temperature is reduced. Since the pressure of the carbon dioxide at this time is higher than that of the carbon dioxide in the cold side of the phase change cold storage device 3 during the energy storage process, and the temperature of the cold storage medium in the phase change cold storage device 3 is lower than the saturation temperature of the carbon dioxide during the power generation process, the cold storage medium absorbs heat and changes phase from near solid state to near liquid state. Through indirect heat exchange, the carbon dioxide releases heat and liquefies.
[0047] Working principle of the preheating cycle unit:
[0048] When the system is in the energy storage mode, the circulating ethylene glycol water solution flows out of the preheating cycle heat tank 22, is transported to the energy storage side preheater 4 to preheat the carbon dioxide, and the ethylene glycol water solution releases heat after the preheating and is stored in the preheating cycle cold tank 20; when the system is in the power generation mode, the ethylene glycol water solution in the preheating cycle cold tank 20 flows out, is transported to the power generation side collector 18 to absorb the sensible heat of the carbon dioxide, is transported to the preheating cycle heat tank 22 for storage after being heated, and the preheating cycle is completed.
[0049] Working principle of the compression and heat recovery cycle unit:
[0050] When the system is in the energy storage mode, the low-temperature water in the compression heat cycle cold tank 28 is compressed into the energy storage side heat collector, the heat of the carbon dioxide at the outlet end of the compressor is recovered, and then flows into the compression heat cycle hot tank 26 for storage; when the system is in the discharging mode, the high-temperature water flows out of the compression heat cycle hot tank 26, is transported to the power generation side regenerator 14 to release heat, and then flows into the compression heat cycle cold tank 28 for storage after being reduced in temperature, to complete the compression heat recovery cycle loop.
[0051] The heat-supplementing type liquid carbon dioxide energy storage system supplements heat into the entire system through the heat-supplementing module, improves the CO2 working temperature, improves the working capacity of the unit mass of CO2, improves the peak power generation capacity of the system, further improves the working flexibility of the LCES system, makes up for the gap in power grid peak regulation, and solves the problem of weak work capacity of the unit mass of CO2 in the charging and discharging cycle process caused by the small pressure ratio between the high-pressure liquid storage tank and the low-pressure liquid storage tank. In an embodiment, the energy storage side cooling module includes an energy storage side air cooler 9, an energy storage side flow dividing valve 10, and an energy storage side water chiller 11. The air inlet end of the energy storage side air cooler 9 is connected with the compression and heat recovery module. The air outlet end of the energy storage side air cooler 9 is connected with a first flow dividing branch and a second flow dividing branch through the energy storage side flow dividing valve 10. The first flow dividing branch and the second flow dividing branch are both connected with the inlet end of the high-pressure liquid storage tank 12, and the heat exchanger of the energy storage side water chiller 11 is connected on the first flow dividing branch. Of course, the energy storage side cooling module can also adopt other settings and other devices.
[0052] Working principle of the energy storage side cooling module:
[0053] During the energy storage process: when the outside air temperature is high (such as summer or days with higher temperature in other seasons, refer to FIG. 1), the carbon dioxide cannot be liquefied by the energy storage side air cooler 9, the energy storage side flow dividing valve 10 opens the first flow dividing branch and closes the second flow dividing branch, all the carbon dioxide is fully condensed and liquefied by the energy storage side water chiller 11, and then enters the high-pressure liquid storage tank 12 for storage; Fig. 3 When the outside air temperature is low (such as winter or days with lower temperature in other seasons, refer to FIG. 2), the carbon dioxide can be completely liquefied by the energy storage side air cooler 9, the energy storage side flow dividing valve 10 opens the second flow dividing branch and closes the first flow dividing branch, and the carbon dioxide directly enters the high-pressure liquid storage tank 12 for storage.
[0054] Fig. 2
[0055] In an embodiment, the compression and heat recovery module comprises a plurality of compression and heat recovery assemblies arranged in series, each of the compression and heat recovery assemblies comprising a compressor and an energy storage side heat collector. The inlet of the energy storage side heat collector of each of the compression and heat recovery assemblies is connected to the compression heat cycle through a compression heat cycle shunt valve 29, a compression heat cycle cold side pump and a compression heat cycle cold tank 28. The outlet of the energy storage side heat collector of each of the compression and heat recovery assemblies is connected to the compression heat cycle through a compression heat cycle bus valve 25 and a compression heat cycle hot tank 26. The compressor of the first compression and heat recovery assembly is connected to the energy storage side preheater 4. The energy storage side heat collector of the last compression and heat recovery assembly is connected to the energy storage side cooling module, such as the energy storage side air cooler 9.
[0056] In the following, the compression and heat recovery module comprises two compression and heat recovery assemblies as an example:
[0057] Specifically, according to the direction of the air flow, the two compression and heat recovery assemblies are divided into a first compression and heat recovery assembly and a second compression and heat recovery assembly. The first compression and heat recovery assembly comprises a first compressor 5 and an energy storage side first heat collector 6 arranged in series. The second compression and heat recovery assembly comprises a second compressor 7 and an energy storage side second heat collector 8 arranged in series. The compression heat cycle cold side pump is provided with two compression heat cycle cold side pumps, i.e. a first compression heat cycle cold side pump 24 and a second compression heat cycle cold side pump 30. The compression heat cycle cold tank 28 is connected to a first circulation branch and a second circulation branch through a compression heat cycle shunt valve 29. The first circulation branch is connected to the inlet of the energy storage side first heat collector 6 through the first compression heat cycle cold side pump 24. The second circulation branch is connected to the inlet of the energy storage side second heat collector 8 through the second compression heat cycle cold side pump 30. The outlet of the energy storage side first heat collector 6 is connected to a third circulation branch. The outlet of the energy storage side second heat collector 8 is connected to a fourth circulation branch. The third circulation branch and the fourth circulation branch are connected to the compression heat cycle hot tank 26 through the compression heat cycle bus valve 25. When the compression heat cycle cold tank 28 releases fluid, the fluid will flow into the energy storage side first heat collector 6 and the energy storage side second heat collector 8 through the first circulation branch and the second circulation branch, respectively. When the compression heat cycle hot tank 26 stores fluid, the fluid of the energy storage side first heat collector 6 and the energy storage side second heat collector 8 will be collected in the compression heat cycle bus valve 25 through the third circulation branch and the fourth circulation branch, and then be collected into the compression heat cycle hot tank 26 through the compression heat cycle bus valve 25.
[0058] In an embodiment, the power generation side cooling module comprises a power generation side air cooler 17. Of course, the power generation side cooling module can also adopt other arrangements and other devices.
[0059] In an embodiment, the power generation side refrigeration module includes a power generation side low-temperature refrigeration unit 19, and the heat exchanger of the power generation side low-temperature refrigeration unit 19 is connected between the hot side of the phase-change cold accumulator 3 and the inlet end of the low-pressure liquid storage tank 1. Of course, the power generation side refrigeration module can also adopt other settings and other devices.
[0060] In an embodiment, the preheating circulating cold tank 20 is connected with the power generation side heat collector 18 (second heat exchange passage) through a preheating circulating cold side pump 21. The preheating circulating hot tank 22 is connected with the energy storage side preheater 4 (second heat exchange passage) through a preheating circulating hot side pump 23.
[0061] In an embodiment, the heat supplement module adopts a solar heat collection device. The solar heat collection device includes a solar low-temperature heat conducting oil tank 31, a solar low-temperature heat conducting oil pump 32, a solar heat collector 33, a solar high-temperature heat conducting oil tank 34, a solar high-temperature heat conducting oil pump 35, and a solar heat conducting oil heat exchanger 15. The first heat exchange passage of the solar heat exchanger 36 is connected between the turbine generator set 16 and the power generation side regenerator 14. The outlet end of the second heat exchange passage of the solar heat exchanger 36 is connected with the inlet end of the solar heat collector 33 in sequence through the solar low-temperature heat conducting oil tank 31, the solar low-temperature heat conducting oil pump 32, and the outlet end of the solar heat collector 33. The outlet end of the solar heat collector 33 is connected with the inlet end of the second heat exchange passage of the solar heat exchanger 36 in sequence through the solar high-temperature heat conducting oil tank 34, the solar high-temperature heat conducting oil pump 35, and the solar heat exchanger 36. In addition, the heat supplement module can also adopt other heating devices such as an electric heating device, etc. in addition to the solar heat collection device for heat supplement.
[0062] The working principle of the solar heat collection device is as follows: The high-temperature heat conducting oil in the solar high-temperature heat conducting oil tank 34 flows out, is transported to the solar heat conducting oil heat exchanger 15 through the solar high-temperature heat conducting oil pump 35 to heat the carbon dioxide, so as to improve the temperature of the carbon dioxide before entering the turbine generator set 16. The heat conducting oil after heat exchange flows into the solar low-temperature heat conducting oil tank 31 for storage. When the light is sufficient, the heat conducting oil in the solar low-temperature heat conducting oil tank 31 flows out, is transported to the solar heat collector 33 through the solar low-temperature heat conducting oil pump 32 to absorb solar energy, is stored in the solar high-temperature heat conducting oil tank 34 after being heated, and the cycle is completed.
[0063] Embodiment 2
[0064] As shown in Figs. 1 to 3 The embodiment provides a use method of the heat-supplement type liquid carbon dioxide energy storage system, which adopts the heat-supplement type liquid carbon dioxide energy storage system in Embodiment 1 and includes the following steps:
[0065] Energy storage process: liquid carbon dioxide in low-pressure liquid storage tank 1 flows out, enters low-temperature expansion valve 2 to throttle and reduce pressure, carbon dioxide flowing out of low-temperature expansion valve 2 enters the cold side of phase change cold accumulator 3 to absorb heat and release cold, and stores cold in the form of latent heat in phase change cold accumulator 3, and liquid carbon dioxide vaporizes into gaseous carbon dioxide after absorbing heat, gaseous carbon dioxide enters energy storage side preheater 4, exchanges heat with fluid flowing out of preheating cycle hot tank 22 and absorbs heat, the cooled fluid flows into preheating cycle cold tank 20 and is stored, and the preheated gaseous carbon dioxide enters the compression and heat recovery module, is first pressurized and heated by the compressor, and then exchanges heat with the fluid flowing out of compression heat cycle cold tank 28 in the energy storage side heat collector and absorbs heat, the heated fluid flows into compression heat cycle hot tank 26 for storage, and then the gaseous carbon dioxide is condensed into liquid carbon dioxide by the energy storage side cooling module, and finally the liquid carbon dioxide enters high-pressure liquid storage tank (12) to complete the system energy storage process.
[0066] Power generation process: liquid carbon dioxide in high-pressure liquid storage tank 12 is pressurized by booster pump 13, the pressurized carbon dioxide enters power generation side regenerator 14, exchanges heat with the fluid flowing out of absorption compression heat cycle hot tank 26 and absorbs heat, the cooled fluid flows into compression heat cycle cold tank 28 for storage, the heated carbon dioxide absorbs heat again by the heat supplement module to increase the temperature of supercritical carbon dioxide, and then expands in turbine generator set 16 to do work, the pressure and temperature of carbon dioxide are both reduced, the carbon dioxide flows through the power generation side cooling module, enters power generation side heat collector 18, exchanges heat with the fluid flowing out of preheating cycle cold tank 20 and releases sensible heat, the heated fluid flows into preheating cycle hot tank 22 for storage, and the cooled carbon dioxide flows into the hot side of phase change cold accumulator 3, the cold storage medium in phase change cold accumulator 3 releases latent heat to liquefy carbon dioxide, and finally the carbon dioxide is fully condensed by the power generation side refrigeration module and is transported to low-pressure liquid storage tank 1 for storage, and the system completes the discharge process.
[0067] In an embodiment, a heat-supplemented liquid carbon dioxide energy storage system in Example 1 is specifically adopted, and the energy storage side cooling module in the heat-supplemented liquid carbon dioxide energy storage system includes energy storage side air cooler 9, energy storage side flow divider valve 10, and energy storage side water chiller 11. The use method further includes the following steps:
[0068] In the energy storage process: when the outside air temperature is high and the carbon dioxide cannot be liquefied by the energy storage side air cooler 9, the energy storage side flow divider valve 10 opens the first flow divider branch and closes the second flow divider branch, and all the carbon dioxide is fully condensed and liquefied by the energy storage side water chiller 11 and then enters high-pressure liquid storage tank 12 for storage; when the outside air temperature is low and the carbon dioxide can be completely liquefied by the energy storage side air cooler 9, the energy storage side flow divider valve 10 opens the second flow divider branch and closes the first flow divider branch, and the carbon dioxide directly enters high-pressure liquid storage tank 12 for storage.
[0069] In an embodiment, the heat-supplementing liquid carbon dioxide energy storage system in Example 1 is specifically adopted, and a solar heat collector is used as the heat-supplementing module. The use method further includes the following steps:
[0070] The working process of the solar heat collector is as follows: the high-temperature heat conducting oil in the solar high-temperature heat conducting oil tank 34 flows out, is transported to the solar heat conducting oil heat exchanger 15 by the solar high-temperature heat conducting oil pump 35, heats the carbon dioxide, increases the temperature of the carbon dioxide before entering the turbine generator set 16, the heat conducting oil after heat exchange flows into the solar low-temperature heat conducting oil tank 31 for storage, when the light is sufficient, the heat conducting oil in the solar low-temperature heat conducting oil tank 31 flows out, is transported to the solar heat collector 33 by the solar low-temperature heat conducting oil pump 32 to absorb solar energy, is stored in the solar high-temperature heat conducting oil tank 34 after being heated to complete the cycle.
[0071] The principle and the embodiment of the present application are described by using specific examples in the present application, and the above description of the examples is only used to help understand the method of the present application and the core idea; meanwhile, for the general technical personnel in the field, according to the idea of the present application, the specific embodiment and the application range will be changed. In conclusion, the content of the specification should not be understood as the limitation of the present application.
Claims
1. A heat-supplementing liquid carbon dioxide energy storage system, characterized in that: It comprises a low-pressure liquid storage tank (1), a phase-change cold storage device (3) and a high-pressure liquid storage tank (12); The liquid outlet of the low-pressure liquid storage tank (1) is connected to the cold side of the phase-change cold storage device (3) through a low-temperature expansion valve (2); an energy storage side preheater (4), a compression and heat recovery module, and an energy storage side cooling module are sequentially connected between the cold side of the phase-change cold storage device (3) and the liquid inlet of the high-pressure liquid storage tank (12) along the airflow direction; the compression and heat recovery module includes a compression and heat recovery component, and the compression and heat recovery component includes a compressor and an energy storage side heat collector arranged in series, and the compressor and the energy storage side heat collector are sequentially arranged along the airflow direction; A booster pump (13), a power generation side heat regenerator (14), a heat supplement module, a turbine generator set (16), a power generation side cooling module, and a power generation side heat collector (18) are sequentially connected between the liquid outlet of the high-pressure liquid storage tank (12) and the hot side of the phase change cold storage device (3) along the air flow direction. A power generation side refrigeration module is connected between the hot side of the phase change cold storage device (3) and the liquid inlet of the low-pressure liquid storage tank (1). The power generation side heat regenerator (14) and the energy storage side heat collector exchange cold and heat through a compression heat cycle hot tank (26) and a compression heat cycle cold tank (28). The power generation side heat collector (18) and the energy storage side preheater (4) exchange cold and heat through a preheating cycle cold tank (20) and a preheating cycle hot tank (22).
2. The heat-supplementing liquid carbon dioxide energy storage system according to claim 1, characterized in that: The energy storage side cooling module comprises an energy storage side air cooler (9), an energy storage side diverter valve (10) and an energy storage side chiller (11); the air inlet end of the energy storage side air cooler (9) is connected to the compression and heat recovery module; the air outlet end of the energy storage side air cooler (9) is connected to a first diverter branch and a second diverter branch via the energy storage side diverter valve (10); the first diverter branch and the second diverter branch are both connected to the liquid inlet of the high-pressure liquid storage tank (12); and the heat exchanger of the energy storage side chiller (11) is connected to the first diverter branch.
3. The heat-compensating liquid carbon dioxide energy storage system according to claim 1, characterized in that: The compression and heat recovery module comprises a plurality of compression and heat recovery components arranged in series, wherein the liquid inlet end of the energy storage side heat collector of the plurality of compression and heat recovery components is connected to the compression heat cycle cold tank (28) through a compression heat cycle diverter valve (29) and a compression heat cycle cold side pump, and the liquid outlet end of the energy storage side heat collector of the plurality of compression and heat recovery components is connected to the compression heat cycle hot tank (26) through a compression heat cycle confluence valve (25). The compressor of the first-stage compression and heat recovery component is connected to the energy storage side preheater (4), and the energy storage side heat collector of the last-stage compression and heat recovery component is connected to the energy storage side cooling module.
4. The heat-compensating liquid carbon dioxide energy storage system according to claim 1, characterized in that: The power generation side cooling module includes a power generation side air cooler (17).
5. The heat-compensating liquid carbon dioxide energy storage system according to claim 1, characterized in that: The power generation side refrigeration module comprises a power generation side low temperature refrigeration unit (19), and the heat exchanger of the power generation side low temperature refrigeration unit (19) is connected between the hot side of the phase change cold storage device (3) and the liquid inlet of the low pressure liquid storage tank (1).
6. The heat-compensating liquid carbon dioxide energy storage system according to claim 1, characterized in that: A preheating cycle cold side pump (21) is provided between the preheating cycle cold tank (20) and the power generation side collector (18), and a preheating cycle hot side pump (23) is provided between the preheating cycle hot tank (22) and the energy storage side preheater (4).
7. The heat-compensating liquid carbon dioxide energy storage system according to claim 6, characterized in that: The heat replenishment module adopts a solar heat collection device, which includes a solar low-temperature heat-conducting oil tank (31), a solar low-temperature heat-conducting oil pump (32), a solar heat collector (33), a solar high-temperature heat-conducting oil tank (34), a solar high-temperature heat-conducting oil pump (35) and a solar heat-conducting oil heat exchanger (15). The first heat exchange path of the solar heat exchanger (36) is connected between the turbine generator set (16) and the power generation side heat regenerator (14). The liquid outlet end of the second heat exchange path of the solar heat exchanger (36) is connected to the liquid inlet end of the solar heat collector (33) through the solar low-temperature heat-conducting oil tank (31) and the solar low-temperature heat-conducting oil pump (32) in sequence. The liquid outlet end of the solar heat collector (33) is connected to the liquid inlet end of the second heat exchange path of the solar heat exchanger (36) through the solar high-temperature heat-conducting oil tank (34) and the solar high-temperature heat-conducting oil pump (35) in sequence.
8. A method for using a heat-supplementing liquid carbon dioxide energy storage system, characterized in that: The heat-compensating liquid carbon dioxide energy storage system according to any one of claims 1 to 7 is used, comprising the following steps: Energy storage process: The liquid carbon dioxide in the low-pressure liquid storage tank (1) flows out and enters the low-temperature expansion valve (2) to throttle and reduce the pressure. The carbon dioxide flowing out of the low-temperature expansion valve (2) enters the cold side of the phase change cold storage device (3) to absorb heat and release cold energy, and stores the cold energy in the phase change cold storage device (3) in the form of latent heat. The liquid carbon dioxide absorbs heat and vaporizes into gaseous carbon dioxide. The gaseous carbon dioxide enters the energy storage side preheater (4) and exchanges heat with the fluid flowing out of the preheating cycle hot tank (22) and absorbs heat. The cooled fluid The fluid flows into the preheating cycle cold tank (20) and is stored. The preheated gaseous carbon dioxide enters the compression and heat recovery module, is first pressurized and heated by the compressor, and then passes through the energy storage side heat collector to exchange heat with the fluid flowing out of the compression heat cycle cold tank (28) and release heat. The fluid after absorbing heat flows into the compression heat cycle hot tank (26) for storage. Then, the gaseous carbon dioxide is condensed into liquid carbon dioxide by the energy storage side cooling module, and finally the liquid carbon dioxide enters the high-pressure liquid storage tank (12) for storage to complete the system energy storage process. Power generation process: the liquid carbon dioxide in the high-pressure liquid storage tank (12) is pressurized by the booster pump (13), and the pressurized carbon dioxide enters the power generation side regenerator (14), exchanges heat with the fluid flowing out of the compression heat absorption circulation hot tank (26) and absorbs heat, and the cooled fluid flows into the compression heat circulation cold tank (28) for storage, and the carbon dioxide after absorbing heat absorbs heat again through the heat supplement module to increase the temperature of the supercritical carbon dioxide, and then expands and performs work in the turbine generator set (16), and the pressure and temperature of the carbon dioxide are reduced, and the carbon dioxide flows through the power generation side cooling module and enters the power generation side heat collector (18), exchanges heat with the fluid flowing out of the preheating circulation cold tank (20) and releases sensible heat, and the fluid after absorbing heat flows into the preheating circulation hot tank (22) for storage, and the cooled carbon dioxide flows into the hot side of the phase change cold storage (3), and the cold storage medium in the phase change cold storage (3) releases latent heat to liquefy the carbon dioxide, and finally is fully condensed by the power generation side refrigeration module and transported to the low-pressure liquid storage tank (1) for storage, and the system completes the discharge process.
9. The method for using the heat-supplementing liquid carbon dioxide energy storage system according to claim 8, characterized in that: The heat-supplementing liquid carbon dioxide energy storage system according to claim 2 further comprises the following steps: During the energy storage process: when the outside air temperature is high and the carbon dioxide cannot be liquefied after passing through the energy storage side air cooler (9), the energy storage side diverter valve (10) opens the first diverter branch and closes the second diverter branch, and all the carbon dioxide is fully condensed and liquefied by the energy storage side chiller (11) before entering the high-pressure liquid storage tank (12) for storage; when the outside air temperature is low and the carbon dioxide can be completely liquefied after passing through the energy storage side air cooler (9), the energy storage side diverter valve (10) opens the second diverter branch and closes the first diverter branch, and the carbon dioxide directly enters the high-pressure liquid storage tank (12) for storage.
10. The method for using the heat-supplementing liquid carbon dioxide energy storage system according to claim 8, characterized in that: The heat-supplementing liquid carbon dioxide energy storage system according to claim 7 further comprises the following steps: The working process of the solar heat collecting device is as follows: the high-temperature heat-conducting oil in the solar high-temperature heat-conducting oil tank (34) flows out and is transported to the solar heat-conducting oil heat exchanger (15) through the solar high-temperature heat-conducting oil pump (35) to heat the carbon dioxide, thereby increasing the temperature of the carbon dioxide before entering the turbine generator (16) group. The heat-conducting oil after heat exchange flows into the solar low-temperature heat-conducting oil tank (31) for storage. When there is sufficient sunlight, the heat-conducting oil in the solar low-temperature heat-conducting oil tank (31) flows out and is transported to the solar collector (33) through the solar low-temperature heat-conducting oil pump (32) to absorb solar energy. After heating, the heat-conducting oil is stored in the solar high-temperature heat-conducting oil tank (34) to complete the cycle.