CN116608022A - Steam circulation type Carnot battery and energy storage method thereof - Google Patents

Steam circulation type Carnot battery and energy storage method thereof Download PDF

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Publication number
CN116608022A
CN116608022A CN202310489493.9A CN202310489493A CN116608022A CN 116608022 A CN116608022 A CN 116608022A CN 202310489493 A CN202310489493 A CN 202310489493A CN 116608022 A CN116608022 A CN 116608022A
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working medium
heat
steam
energy storage
cycle
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王建强
沈佳杰
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Shanghai Institute of Applied Physics of CAS
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Shanghai Institute of Applied Physics of CAS
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Priority to CN202310489493.9A priority Critical patent/CN116608022A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K25/00—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for
    • F01K25/08—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for using special vapours
    • F01K25/10—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for using special vapours the vapours being cold, e.g. ammonia, carbon dioxide, ether
    • F01K25/106—Ammonia
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D15/00—Adaptations of machines or engines for special use; Combinations of engines with devices driven thereby
    • F01D15/10—Adaptations for driving, or combinations with, electric generators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K11/00—Plants characterised by the engines being structurally combined with boilers or condensers
    • F01K11/02—Plants characterised by the engines being structurally combined with boilers or condensers the engines being turbines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K13/00—General layout or general methods of operation of complete plants
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K13/00—General layout or general methods of operation of complete plants
    • F01K13/006—Auxiliaries or details not otherwise provided for
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K27/00—Plants for converting heat or fluid energy into mechanical energy, not otherwise provided for
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B30/00—Heat pumps
    • F25B30/02—Heat pumps of the compression type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D20/00—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
    • F28D20/0034—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00 using liquid heat storage material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D20/00—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
    • F28D20/0034—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00 using liquid heat storage material
    • F28D2020/0047—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00 using liquid heat storage material using molten salts or liquid metals

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Engine Equipment That Uses Special Cycles (AREA)

Abstract

The application provides an energy storage method of a steam circulation type Carnot battery, which comprises an energy storage mode and a power supply mode. In the energy storage mode, after the gaseous working medium is compressed in a compressor in an adiabatic mode, the pressure and the temperature are increased simultaneously, then the gaseous working medium enters a condenser to release heat to an energy storage system, the working medium is condensed into a liquid working medium after the temperature of the working medium is reduced, the pressure of the liquid working medium is reduced after the liquid working medium enters a throttle valve, then the working medium enters an evaporator, and the working medium enters the compressor again for repeated circulation after the working medium is evaporated into the gaseous working medium. In the power supply mode, the steam power circulation of the working medium is realized, the working medium is used for generating electricity through the function of the steam turbine to the outside, and the liquid working medium is subjected to phase change through the second evaporator. The application also provides a corresponding steam circulation type Carnot battery. The steam circulation type Carnot battery overcomes the defect of low conversion efficiency of the traditional electric heating heat storage medium energy storage mode, and simultaneously optimizes the problem that the reversible Brayton cycle has higher requirements on the device.

Description

Steam circulation type Carnot battery and energy storage method thereof
Technical Field
The application relates to an energy storage method and device of a Carnot battery, in particular to a steam circulation type Carnot battery and an energy storage method thereof.
Background
The green energy source represented by solar energy, wind energy and hydraulic potential energy has the advantages of environmental protection and inexhaustible energy, however, since the green energy source is generally influenced by natural conditions such as weather, seasons, sunlight and the like, it is difficult to provide stable energy output, and thus it is difficult to output electric power matched with a power grid. Therefore, a certain energy storage technology is adopted, and space is replaced by time, so that the method is a better solution. Physical energy storage represented by molten salt energy storage has the characteristics of low cost, high efficiency, simple structure and the like. Currently, heat is stored mainly by means of electric heating or by means of an electrically heated heat conducting medium. But has the disadvantage that the conversion efficiency between heat storage and power generation is still not ideal.
The prior patent (a heat pump type energy storage power supply and heat supply method and device ZL201711402735.7 and a heat pump type alternate energy storage power supply method and device ZL 201810180017.8) of the inventor discloses two heat pump type energy storage power supply and heat supply methods and devices, and the energy storage power generation principle is realized by mutually reversible Brayton cycle, and the energy storage is realized by the reverse Brayton cycle, and the electrical power is generated by the Brayton cycle. However, the brayton cycle power generation has an advantage in that the thermoelectric conversion efficiency is high at high temperature. Because molten salt has high corrosiveness to metals at high temperature and has high corrosiveness to common metals at more than 700 ℃, the actual energy storage temperature can be controlled between 500 ℃ and 700 ℃, the advantage of high efficiency of the Brayton cycle cannot be fully exerted, on the other hand, the Brayton cycle has high requirements on equipment, a gas turbine is needed, and the cost of the gas turbine is generally higher than that of steam cycle equipment.
Disclosure of Invention
The application aims to provide an energy storage method of a steam circulation type Carnot battery, which aims to overcome the defect of low energy storage efficiency of a traditional electric heating heat storage medium, and simultaneously optimize the problem of high requirements on a device by reversible Brayton cycle.
In order to achieve the above object, a method for storing energy in a steam cycle type carnot battery is characterized by comprising the following modes:
(1) In the energy storage mode, the pressure and the temperature of a low-pressure gaseous working medium are increased after the working medium is compressed in a heat insulation way through a compressor, then the pressure and the temperature are increased simultaneously, the heat is released to the energy storage system through the isobaric heat release of a first condenser, the temperature of the working medium is reduced and condensed into a high-pressure liquid working medium, the pressure of the liquid working medium is reduced into a low-temperature low-pressure liquid working medium after entering a throttle valve, the liquid working medium is subjected to isobaric heat absorption through the heat exchange of the first evaporator and a low-temperature heat source, and the liquid working medium is evaporated into the low-pressure gaseous working medium and then enters the compressor again to repeat the process, so that the heat pump circulation of the compressor of the working medium is realized;
(2) In a power supply mode, realizing steam power circulation of a working medium, wherein the steam power circulation is Rankine cycle or kalina cycle; in the steam power cycle, the working medium exchanges heat with the energy storage system through the isobaric heat absorption of the second evaporator by using the external function of the steam turbine, so that the temperature of the liquid working medium rises and is evaporated into high-temperature high-pressure steam;
the low pressure refers to the evaporation pressure of the working medium evaporated into a low-pressure gaseous state in the energy storage mode; the high pressure refers to the condensation pressure of the working medium condensed into a high-pressure liquid working medium in the energy storage mode, and the evaporation pressure when the working medium evaporated into a high-temperature high-pressure steam form in the power supply mode is equal to the condensation pressure of the working medium condensed into a high-pressure liquid working medium in the energy storage mode; the high temperature refers to the evaporation temperature of the working medium at the high pressure.
The steam power cycle is a rankine cycle; the rankine cycle includes: the temperature of the liquid working medium rises through the second evaporator and is evaporated into a working medium in a steam form, the working medium in the steam form enters the steam turbine after being overheated by the heater to do adiabatic expansion to do work externally, then the working medium discharged by the steam turbine releases heat in the second condenser, the working medium is condensed into the liquid working medium, and the working medium pump pressurizes the liquid working medium to the second evaporator to repeat the process; or alternatively
The steam power cycle is a kalina cycle; the kalina cycle includes: the ammonia water solution is converted into ammonia water gas-liquid mixture through isobaric heat absorption of a second evaporator, and enters a separator; separating the ammonia-water gas-liquid mixture into ammonia-rich steam and ammonia-poor solution by using a separator, wherein the ammonia-rich steam enters a steam turbine to perform adiabatic expansion to do external work, the ammonia-poor solution enters a heat exchanger to preheat the ammonia-water solution before entering a second evaporator, then the ammonia-water solution is throttled and depressurized by a throttle valve, then the ammonia-water solution and the ammonia-rich steam discharged from the steam turbine are mixed in a mixer to form the ammonia-water solution, the ammonia-water solution enters the second condenser to perform isobaric heat release, the pressure is increased by a working medium pump, then the ammonia-water solution enters the heat exchanger to be preheated by the ammonia-poor solution, and then the ammonia-water solution returns to the second evaporator and repeats the process.
When the steam power cycle is a rankine cycle, the working medium is water or an organic solvent, and the organic solvent comprises one of hydrocarbons, alcohols, ethers, esters, ketones, aldehydes, phenols, carboxylic acids, amines, glycol derivatives and heterocyclic compounds; when the steam power cycle is a kalina cycle, the working medium is an ammonia water solution.
The energy storage system comprises a liquid energy storage system, and a heat storage medium of the liquid energy storage system is molten salt or heat conduction oil; or a solid state energy storage system, the thermal storage medium of which is a solid state thermal storage medium comprising a metal oxide or silicate.
The low-temperature heat source comprises an air source heat source, a power generation system waste heat source, an industrial waste heat source, a geothermal heat source and one of heat released by a condenser by a working medium in a power supply mode, and heat storage mediums with different working temperatures are matched for different low-temperature heat sources to store energy and working mediums with different boiling points.
In another aspect, the application provides a steam cycle type carnot battery, which comprises an energy storage system, a heat pump cycle working device connected with the energy storage system through a first condenser, and a heat engine cycle working device connected with the energy storage system through a second evaporator; the heat pump cycle working device comprises a compressor, a first condenser, a throttle valve and a first evaporator, wherein the compressor, the first condenser, the throttle valve and the first evaporator are sequentially connected in series by pipelines along the trend of a working medium and form a loop; the heat pump cycle working device is arranged to realize the compressor heat pump cycle of working medium in an energy storage mode; the heat engine circulation working device is arranged to realize the steam power circulation of working medium in a power supply mode; the heat engine circulation working device at least comprises a steam turbine and a second evaporator, the heat turbine is used for generating electricity through the external function of the steam turbine, and the working medium exchanges heat with the energy storage system through the isobaric heat absorption of the second evaporator, so that the temperature of the liquid working medium rises and is evaporated into high-temperature high-pressure steam.
The heat engine circulation working device comprises a second evaporator, a superheater, a steam turbine, a second condenser and a working medium pump which are sequentially connected in series by pipelines along the trend of the working medium to form a loop, so as to realize the Rankine cycle of the working medium in a power supply mode; or the heat engine circulation working device comprises a second evaporator, a separator, a steam turbine, a mixer, a second condenser, a working medium pump and a heat exchanger which are sequentially connected in series by pipelines along the trend of the working medium and form a loop; the separator comprises an ammonia-rich steam outlet and an ammonia-poor solution outlet, and the ammonia-rich steam outlet is connected with the steam turbine; the mixer is provided with two input ports, wherein one input port is connected with the steam turbine; the heat exchanger is provided with a pipe side and a shell side, and is connected with the working medium pump and the second evaporator through the pipe side; a shell side and a throttle valve of the heat exchanger which are sequentially connected in series along the trend of the working medium are also arranged between the lean ammonia solution outlet of the separator and the other input port of the mixer; thereby, the kalina cycle of the ammonia solution is realized in the power supply mode.
The working medium comprises one of water, ammonia water solution and an organic solvent, and the organic solvent comprises one of hydrocarbon, alcohol, ether, ester, ketone, aldehyde, phenol, carboxylic acid, amine, glycol derivative and heterocyclic compound.
The energy storage system comprises a liquid energy storage system, and the heat storage medium of the energy storage system is a liquid heat storage medium comprising at least one of molten salt and heat conduction oil; or a solid state energy storage system, the thermal storage medium of which is a solid state thermal storage medium comprising a metal oxide or silicate.
The energy storage system is a liquid energy storage system, and the liquid energy storage system comprises at least two heat storage medium heat preservation containers which are communicated with each other and have different temperatures of internal liquid heat storage mediums or at least one heat storage medium heat preservation container which is communicated with each other and has an inclined temperature layer with a temperature difference gradient of the internal liquid heat storage mediums.
The steam circulation type Carnot battery overcomes the defect of low energy storage efficiency of the traditional electric heating heat storage medium, simultaneously optimizes the problem of high requirements on the device by the reversible Brayton cycle, and can solve the problems of wind abandon and light abandon in photovoltaic power generation and wind energy power generation.
Specifically, the principle that the carnot cycle and the reverse carnot cycle are reversible in thermodynamics is used as a reference, heat of a low-temperature heat source is transferred to a high-temperature heat source to store energy through heat pump cycle working of a compressor, and then working medium is heated to generate steam when heat of the high-temperature heat source is transferred to the low-temperature heat source, so that a steam turbine is driven to do work to the outside to realize power generation. Because the heat pump effectively utilizes the low-grade heat energy of the low-temperature heat source, the conversion efficiency of the power generation after energy storage is generally superior to that of the traditional modes such as direct electric heating or electric heating of heat conducting media. The energy storage mode has the characteristic of low cost, the cost of molten salt is very low, and the cost of stainless steel used as a container is also low, so after the energy storage method is adopted, the conversion efficiency of power generation is superior to that of modes such as direct electric heating energy storage and the like.
In addition, the steam cycle type Carnot battery disclosed by the application utilizes the principle that reversible steam power cycle replaces reversible Brayton cycle as energy storage, utilizes the steam power cycle technology to replace a gas turbine with higher cost, is mature, can be transformed by utilizing existing steam power cycle equipment of a power plant, and reduces the cost of thermodynamic cycle; meanwhile, the heat pump of the compressor with mature technology is adopted to store energy in a circulating way, so that electric heating conversion is realized; the Rankine cycle is utilized to generate power to realize thermoelectric conversion, so that the cost is low and the technology is more mature.
Drawings
Fig. 1 is a schematic structural view of a rankine cycle type carnot battery according to an embodiment of the present application.
Fig. 2 is a schematic structural diagram of a kalina cycle type carnot battery according to an embodiment of the present application.
Reference numerals:
1. a compressor; 2. a first condenser; 3. a throttle valve; 4. a first evaporator; 5. a low temperature molten salt storage tank set; 6. a high temperature molten salt storage tank group; 7. a first molten salt pump; 8. a second molten salt pump; 9. a third molten salt pump; 10. a fourth molten salt pump; 11. a second evaporator; 12. a superheater; 13. a steam turbine; 14. a second condenser; 15. a working medium pump; 16. a separator; 17. a heat exchanger; 18. a mixer; 19. a throttle valve.
Detailed Description
Preferred embodiments of the present application will be described in detail with reference to the accompanying drawings.
First embodiment: rankine cycle type Carnot battery
Fig. 1 is a schematic view showing the structure of a rankine cycle type carnot battery according to a first embodiment of the present application, that is, in this embodiment, the steam power cycle of the steam cycle type carnot battery of the present application is a rankine cycle.
As shown in fig. 1, the rankine cycle type carnot battery includes an energy storage system, a heat pump cycle operating device connected to the energy storage system through a first condenser 2, and a heat engine cycle operating device connected to the energy storage system through a second evaporator 11. Wherein the working medium of the heat pump cycle working device and the working medium of the heat engine cycle working device are the same liquid (steam) working medium.
The heat pump cycle working device comprises a compressor 1, a first condenser 2, a throttle valve 3 and a first evaporator 4 which are sequentially connected in series by pipelines along the trend of a working medium and form a loop, and the first evaporator exchanges heat with a low-temperature heat source. The heat pump cycle operating device is arranged to effect a compressor heat pump cycle of the operating medium in the energy storage mode.
The energy storage system comprises a heat storage medium and realizes energy storage and energy release through the heat storage medium. The heat storage medium comprises a liquid heat storage medium such as molten salt, heat conducting oil and the like, and a solid heat storage medium comprising metal oxide or silicate. Thus, the energy storage system may be a liquid energy storage system in which the thermal storage medium is a liquid thermal storage medium or a solid energy storage system in which the thermal storage medium is a solid thermal storage medium.
In this embodiment, the energy storage system is a liquid energy storage system, which includes a first molten salt pump 7, a first condenser 2, a second molten salt pump 8, a high-temperature molten salt tank set 6, a third molten salt pump 9, a fourth molten salt pump 10, and a low-temperature molten salt tank set 5, which are sequentially connected in series along the trend of the heat storage medium and form a loop.
In this embodiment, the heat engine cycle working device comprises a second evaporator 11, a superheater 12, a steam turbine 13, a second condenser 14 and a working medium pump 15 which are connected in series and form a loop by pipelines in the running direction of the working medium. The heat engine cycle working device is arranged to realize the Rankine cycle of a working medium in a power supply mode, and externally operated functions in the Rankine cycle are used for generating power.
Second embodiment: energy storage method of Rankine cycle type Carnot battery
Based on the Rankine cycle type Carnot battery, the energy storage method of the Rankine cycle type Carnot battery comprises the following steps:
(1) In the energy storage mode, the pressure and the temperature of a low-pressure gaseous working medium are increased simultaneously after the working medium is compressed in an adiabatic manner by the compressor 1, and then the heat is exchanged with the energy storage system through isobaric heat release by the first condenser 2, so that the heat is released to the energy storage system, and meanwhile, the working medium is condensed into a high-pressure liquid working medium after the temperature of the working medium is reduced. Then, the pressure of the liquid working medium is reduced to be a low-temperature low-pressure liquid working medium after entering the throttle valve 3, the liquid working medium exchanges heat with a low-temperature heat source through the first evaporator 4 to perform isobaric heat absorption, and the liquid working medium is evaporated to be a low-pressure gaseous working medium after absorbing the heat of the low-temperature heat source and then enters the compressor 1 again to repeat the process, so that the compressor heat pump cycle of the working medium is realized.
Thereby, a compressor heat pump cycle (like an air conditioner) is realized by the compressor 1, the first condenser 2, the throttle valve 3, the first evaporator 4. In the heat pump cycle, the heat of the low-temperature heat source is transferred to the high-temperature heat source through the work of the compressor 1 to realize energy storage.
In this embodiment, the heat storage medium is molten salt, and heat is released to the energy storage system by heat exchange between the working medium and the energy storage system, so that the temperature of the heat storage medium in the energy storage system is increased. Specifically, the heat storage medium (i.e. low-temperature molten salt) flows out of the low-temperature molten salt storage tank group 5, enters the first condenser 2 through the first molten salt pump 7 to exchange heat with the working medium, and after the heat storage medium obtains heat energy, the temperature of the heat storage medium rises to become high-temperature heat storage medium, and enters the high-temperature molten salt storage tank group 6 through the second molten salt pump 8. At the same time, the working medium is condensed into a liquid working medium after the temperature of the working medium is reduced.
(2) In the power supply mode, the steam power circulation of the working medium is realized; in the steam power cycle, the steam turbine is used for generating electricity through an external function, and the second evaporator is used for carrying out isobaric heat absorption to exchange heat with the energy storage system, so that the temperature of a liquid working medium rises and is evaporated into high-temperature high-pressure steam.
In this embodiment, the steam power cycle is a rankine cycle, and therefore, the rankine cycle includes: the working medium exchanges heat with the energy storage system through the isobaric heat absorption of the second evaporator 11, so that the heat of the energy storage system is absorbed, the temperature of the liquid working medium rises and is evaporated into the working medium in a high-temperature high-pressure steam form, the working medium in the steam form enters the steam turbine 13 to perform adiabatic expansion to do work externally after being overheated by the heater 12, then the working medium discharged by the steam turbine 13 releases heat in an equal pressure manner in the second condenser 14 and is condensed into the liquid working medium, and the working medium pump 15 pressurizes the liquid working medium into the second evaporator 11 to repeat the process, so that the Rankine cycle of the working medium is realized.
Thus, the rankine cycle is realized by the second evaporator 11, the superheater 12, the steam turbine 13, the second condenser 14, and the working medium pump 15, and power is generated by work externally performed in the rankine cycle.
It should be noted that, the low pressure refers to the evaporation pressure of the working medium evaporated to a low pressure gaseous state in the energy storage mode, and the condensation pressure of the working medium condensed to a liquid state in the power supply mode is equal to the evaporation pressure of the working medium evaporated to a low pressure gaseous state in the energy storage mode; the high pressure refers to the condensation pressure of the working medium condensed into a high-pressure liquid working medium in the energy storage mode, the evaporation pressure when the working medium evaporated into a high-temperature high-pressure steam form in the power supply mode is equal to the condensation pressure when the working medium condensed into a high-pressure liquid working medium in the energy storage mode, the pressure difference between the two is determined according to the compression ratio of the compressor, and the compression ratio of the high pressure and the low pressure is generally between 10 and 25.
The high temperature here refers to the evaporation temperature of the working medium at high pressure. Different working media, the temperature is different, for example, the highest evaporating temperature of water is 384 ℃, and high-temperature steam with the temperature of more than 500 ℃ can be obtained after the water is overheated and is used for pushing the steam turbine to do work. The evaporation temperature of the working medium using the organic working medium is much lower.
The heat exchange of the working medium with the energy storage system causes heat from the energy storage system to be released and the temperature of the thermal storage medium in the energy storage system to decrease. Specifically, the heat storage medium (i.e. high-temperature molten salt) flows out of the high-temperature molten salt storage tank group 6, enters the second evaporator 11 through the third molten salt pump 9 to exchange heat with the liquid working medium, and after the heat storage medium releases heat, the temperature of the heat storage medium is reduced to be low-temperature working medium, and enters the low-temperature molten salt storage tank group 5 through the molten salt pump 10. Meanwhile, the working medium is evaporated into high-temperature high-pressure steam after the temperature of the working medium rises.
Third embodiment: carlenna circulation type Carnot battery
Fig. 2 is a schematic structural diagram of a carnina cycle type carnot battery according to an embodiment of the present application, that is, in this embodiment, a steam power cycle of the steam cycle type carnot battery is a carnina cycle.
As shown in fig. 2, the kalina cycle type carnot battery comprises an energy storage system, a heat pump cycle working device connected with the energy storage system through a first condenser 2, and a heat engine cycle working device connected with the energy storage system through a second evaporator 11. Wherein the working medium of the heat pump cycle working device and the working medium of the heat engine cycle working device are the same liquid (steam) working medium.
The heat pump cycle working device comprises a compressor 1, a first condenser 2, a throttle valve 3 and a first evaporator 4 which are connected in series by pipelines in sequence along the trend of a working medium and form a loop, and the first evaporator exchanges heat with a low-temperature heat source. The heat pump cycle operating device is arranged to effect a compressor heat pump cycle of the operating medium. Wherein the working medium is ammonia water solution.
The energy storage system comprises a heat storage medium and realizes energy storage and energy release through the heat storage medium. The heat storage medium comprises a liquid heat storage medium such as molten salt, heat conducting oil and the like, and a solid heat storage medium comprising metal oxide or silicate. Thus, the energy storage system may be a liquid energy storage system in which the thermal storage medium is a liquid thermal storage medium or a solid energy storage system in which the thermal storage medium is a solid thermal storage medium. In this embodiment, the energy storage system is a liquid energy storage system, which includes a first molten salt pump 7, a first condenser 2, a second molten salt pump 8, a high-temperature molten salt tank set 6, a third molten salt pump 9, a fourth molten salt pump 10, and a low-temperature molten salt tank set 5, which are sequentially connected in series along the trend of the heat storage medium and form a loop.
In this embodiment, the heat engine cycle working device comprises a second evaporator 11, a separator 16, a steam turbine 13, a mixer 18, a second condenser 14, a working medium pump 15 and a heat exchanger 17, which are connected in series and form a loop by pipelines in the direction of the working medium. The separator 16 comprises an ammonia rich vapor outlet and an ammonia lean solution outlet, the ammonia rich vapor outlet being connected to said turbine 13. The mixer 18 has two input ports, one of which is connected to the steam turbine 13. The heat exchanger 17 has a tube side and a shell side, and is connected to the working medium pump 15 and the second evaporator 11 via the tube side. Furthermore, a shell side of the heat exchanger 17 and a throttle valve 19, which are connected in series in the direction of the working medium, are also provided between the ammonia-lean solution outlet of the separator 16 and the other inlet of the mixer 18. Thereby, a kalina cycle of the working medium is realized in the power supply mode.
The heat engine circulation working device is arranged to realize the kalina circulation of working media, and functions of the kalina circulation are used for generating electricity.
Fourth embodiment: energy storage method of kalina circulating type Carnot battery
Based on the Rankine cycle type Carnot battery, the energy storage method of the Rankine cycle type Carnot battery comprises the following steps:
(1) In the energy storage mode, the pressure and the temperature of a low-pressure gaseous working medium are increased simultaneously after the working medium is compressed in an adiabatic manner by the compressor 1, and then the heat is exchanged with the energy storage system through isobaric heat release by the first condenser 2, so that the heat is released to the energy storage system, and meanwhile, the working medium is condensed into a high-pressure liquid working medium after the temperature of the working medium is reduced. Then, the pressure of the liquid working medium is reduced to be a low-temperature low-pressure liquid working medium after entering the throttle valve 3, the liquid working medium exchanges heat with the low-temperature heat source through the first evaporator 4 to perform isobaric heat absorption, and the liquid working medium is evaporated to be a low-pressure gaseous working medium after absorbing the heat of the low-temperature heat source and then enters the compressor 1 again to repeat the process.
Thereby, a compressor heat pump cycle (like an air conditioner) is realized by the compressor 1, the first condenser 2, the throttle valve 3, the first evaporator 4.
In the heat pump cycle, the heat of the low-temperature heat source is transferred to the high-temperature heat source through the work of the compressor 1 to realize energy storage. In the application, the main source of low-temperature heat source is industrial heat, such as waste heat of a power plant, and also can be waste heat of Rankine cycle; the high temperature heat source is the heat of the high temperature heat storage medium.
In this embodiment, the heat storage medium is molten salt, and heat is released to the energy storage system by heat exchange between the working medium and the energy storage system, so that the temperature of the heat storage medium in the energy storage system is increased. Specifically, the heat storage medium (i.e. low-temperature molten salt) flows out of the low-temperature molten salt storage tank group 5, enters the first condenser 2 through the first molten salt pump 7 to exchange heat with the working medium, and after the heat storage medium obtains heat energy, the temperature of the heat storage medium rises to become high-temperature heat storage medium, and enters the high-temperature molten salt storage tank group 6 through the second molten salt pump 8. At the same time, the working medium is condensed into a liquid working medium after the temperature of the working medium is reduced.
(2) In the power supply mode, the steam power circulation of the working medium is realized; in the steam power cycle, the steam turbine is used for generating electricity through an external function, and the second evaporator is used for carrying out isobaric heat absorption to exchange heat with the energy storage system, so that the temperature of a liquid working medium rises and is evaporated into high-temperature high-pressure steam.
In this embodiment, the steam power cycle is a kalina cycle, so the working medium is an ammonia solution, and the kalina cycle includes: the ammonia solution exchanges heat with the energy storage system by means of isobaric heat absorption by the second evaporator 11, thereby absorbing heat of the energy storage system, so that the ammonia solution is isobarically absorbed and becomes an ammonia gas-liquid mixture, and enters the separator 16, and then the ammonia gas-liquid mixture is separated into ammonia-rich vapor and ammonia-lean solution by the separator 16. Wherein, the ammonia-rich steam enters a steam turbine 13 to carry out adiabatic expansion so as to do work outwards; the lean ammonia solution enters the heat exchanger 17 to preheat the ammonia solution before entering the second evaporator 11 by utilizing the liquid part, the lean ammonia solution is throttled and depressurized through the throttle valve 19 after being discharged, then is mixed with the rich ammonia steam discharged from the steam turbine 13 in the mixer 18 to form the ammonia solution, enters the second condenser 14 to carry out isobaric heat release to condense the ammonia solution into liquid ammonia solution, is boosted by the working medium pump 15, then enters the heat exchanger 17 to be preheated by the lean ammonia solution, and then the ammonia solution returns to the second evaporator 11 and repeats the process, thus completing the cycle.
It should be noted that, the low pressure refers to the evaporation pressure of the working medium evaporated to a low pressure gaseous state in the energy storage mode, and the condensation pressure of the working medium condensed to a liquid state in the power supply mode is equal to the evaporation pressure of the working medium evaporated to a low pressure gaseous state in the energy storage mode; the high pressure refers to the condensation pressure of the liquid working medium in which the working medium in the energy storage mode is condensed to a high pressure, the pressure difference between the two is determined according to the compression ratio of the compressor, and the compression ratio of the high pressure to the low pressure is generally between 10 and 25.
The high temperature here refers to the evaporation temperature of the working medium at high pressure. Different working media, the temperature is different, for example, the highest evaporating temperature of water is 384 ℃, and high-temperature steam with the temperature of more than 500 ℃ can be obtained after the water is overheated and is used for pushing the steam turbine to do work. The evaporation temperature of the working medium using the organic working medium is much lower.
In this embodiment, the liquid ammonia solution is a liquid working medium, and the working medium in the form of a gas-liquid mixture is an ammonia gas-liquid mixture.
The working medium may be water, or an organic solvent such as hydrocarbons, alcohols, ethers, esters, ketones, aldehydes, phenols, carboxylic acids, amines, glycol derivatives, or heterocyclic compounds, in addition to an aqueous ammonia solution.
In the application, the main source of low-temperature heat source is industrial heat, such as waste heat of a power plant, and also can be waste heat of Rankine cycle; that is, the low-temperature heat source comprises an air source heat source, a power generation system waste heat source, an industrial waste heat source, a low-heat source and heat released by a working medium in a power supply mode in the application, and heat storage mediums with different working temperatures are matched for different low-temperature heat sources to store energy and working mediums with different boiling points. The high temperature heat source is the heat of the high temperature heat storage medium. The low-temperature heat source is a heat source below 200 ℃, the molten salt is nitrate or chloride, the temperature of the nitrate is 290-550 ℃ in the range of binary nitrate, and the temperature of the ternary nitrate is 200-380 ℃.
In other embodiments, the thermal storage medium comprises a liquid thermal storage medium such as a molten salt, a thermally conductive oil, or the like, and a solid thermal storage medium comprising a metal oxide or silicate. The energy storage system may be a liquid energy storage system in which the thermal storage medium is a liquid thermal storage medium or a solid energy storage system in which the thermal storage medium is a solid thermal storage medium. The liquid energy storage system comprises at least two heat storage medium heat preservation containers which are communicated with each other and have different temperatures of the internal liquid heat storage medium or at least one heat storage medium heat preservation container which is communicated with each other and has an inclined temperature layer with a temperature difference gradient of the internal liquid heat storage medium.
The steam circulation type Carnot battery overcomes the defect of low energy storage efficiency of the traditional electric heating heat storage medium, simultaneously optimizes the problem of high requirements on the device by the reversible Brayton cycle, and can solve the problems of wind abandon and light abandon in photovoltaic power generation and wind energy power generation.
Specifically, the principle that the carnot cycle and the reverse carnot cycle are reversible in thermodynamics is used as a reference, heat of a low-temperature heat source is transferred to a high-temperature heat source to store energy through heat pump cycle working of a compressor, and then working medium is heated to generate steam when heat of the high-temperature heat source is transferred to the low-temperature heat source, so that a steam turbine is driven to do work to the outside to realize power generation. Because the heat pump effectively utilizes the low-grade heat energy of the low-temperature heat source, the conversion efficiency of the power generation after energy storage is generally superior to that of the traditional modes such as direct electric heating or electric heating of heat conducting media. The energy storage mode has the characteristic of low cost, the cost of molten salt is very low, and the cost of stainless steel used as a container is also low, so after the energy storage method is adopted, the conversion efficiency of power generation is superior to that of modes such as direct electric heating energy storage and the like.
In addition, the steam cycle type Carnot battery disclosed by the application utilizes the principle that reversible steam power cycle replaces reversible Brayton cycle as energy storage, utilizes the steam power cycle technology to replace a gas turbine with higher cost, is mature, can be transformed by utilizing existing steam power cycle equipment of a power plant, and reduces the cost of thermodynamic cycle; meanwhile, the heat pump of the compressor with mature technology is adopted to store energy in a circulating way, so that electric heating conversion is realized; the Rankine cycle is utilized to generate power to realize thermoelectric conversion, so that the cost is low and the technology is more mature.
The steam power cycle adopts water or an organic working medium as a circulating working medium, molten salt or heat conducting oil is used as a heat storage medium, a compressor heat pump is used for converting a low-grade heat source such as an air heat source or industrial waste heat into a high-grade heat source, the high-grade heat source is stored in the heat storage medium, and the heat energy stored in the heat storage medium is used for generating electricity through the steam power cycle (Rankine cycle or kalina cycle) through an evaporator during power supply.
The foregoing description is only a preferred embodiment of the present application, and is not intended to limit the scope of the present application, and various modifications can be made to the above-described embodiment of the present application. All simple, equivalent changes and modifications made in accordance with the claims and the specification of this application fall within the scope of the patent claims. The present application is not described in detail in the conventional art.

Claims (9)

1. The energy storage method of the steam circulation type Carnot battery is characterized by comprising the following modes:
(1) In the energy storage mode, the pressure and the temperature of a low-pressure gaseous working medium are increased after the working medium is compressed in a heat insulation way through a compressor, then the pressure and the temperature are increased simultaneously, the heat is released to the energy storage system through the isobaric heat release of a first condenser, the temperature of the working medium is reduced and condensed into a high-pressure liquid working medium, the pressure of the liquid working medium is reduced into a low-temperature low-pressure liquid working medium after entering a throttle valve, the liquid working medium is subjected to isobaric heat absorption through the heat exchange of the first evaporator and a low-temperature heat source, and the liquid working medium is evaporated into the low-pressure gaseous working medium and then enters the compressor again to repeat the process, so that the heat pump circulation of the compressor of the working medium is realized;
(2) In a power supply mode, realizing steam power circulation of a working medium, wherein the steam power circulation is Rankine cycle or kalina cycle; in the steam power cycle, the working medium exchanges heat with the energy storage system through the isobaric heat absorption of the second evaporator by using the external function of the steam turbine, so that the temperature of the liquid working medium rises and is evaporated into high-temperature high-pressure steam;
the low pressure refers to the evaporation pressure of the working medium evaporated into a low-pressure gaseous state in the energy storage mode; the high pressure refers to the condensation pressure of the working medium condensed into a high-pressure liquid working medium in the energy storage mode, and the evaporation pressure when the working medium evaporated into a high-temperature high-pressure steam form in the power supply mode is equal to the condensation pressure of the working medium condensed into a high-pressure liquid working medium in the energy storage mode; the high temperature refers to the evaporation temperature of the working medium at the high pressure.
2. The method of storing energy in a steam cycle type canola cell of claim 1, wherein the steam power cycle is a rankine cycle; the rankine cycle includes: the temperature of the liquid working medium rises through the second evaporator and is evaporated into a working medium in a steam form, the working medium in the steam form enters the steam turbine after being overheated by the heater to do adiabatic expansion to do work externally, then the working medium discharged by the steam turbine releases heat in the second condenser, the working medium is condensed into the liquid working medium, and the working medium pump pressurizes the liquid working medium to the second evaporator to repeat the process; the condensing pressure of the working medium condensed into a liquid state is equal to the evaporating pressure of the working medium evaporated into a low-pressure gaseous state in the energy storage mode; or alternatively
The steam power cycle is a kalina cycle; the kalina cycle includes: the ammonia water solution is converted into ammonia water gas-liquid mixture through isobaric heat absorption of a second evaporator, and enters a separator; separating the ammonia-water gas-liquid mixture into ammonia-rich steam and ammonia-poor solution by using a separator, wherein the ammonia-rich steam enters a steam turbine to perform adiabatic expansion to do external work, the ammonia-poor solution enters a heat exchanger to preheat the ammonia-water solution before entering a second evaporator, then the ammonia-water solution is throttled and depressurized by a throttle valve, then the ammonia-water solution and the ammonia-rich steam discharged from the steam turbine are mixed in a mixer to form the ammonia-water solution, the ammonia-water solution enters the second condenser to perform isobaric heat release, the pressure is increased by a working medium pump, then the ammonia-water solution enters the heat exchanger to be preheated by the ammonia-poor solution, and then the ammonia-water solution returns to the second evaporator and repeats the process.
3. The energy storage method of a steam cycle type carnot cell according to claim 2, wherein when the steam power cycle is a rankine cycle, the working medium is water or an organic solvent including one of hydrocarbons, alcohols, ethers, esters, ketones, aldehydes, phenols, carboxylic acids, amines, glycol derivatives, and heterocyclic compounds; when the steam power cycle is a kalina cycle, the working medium is the ammonia water solution.
4. The energy storage method of a steam cycle type carnot cell according to claim 1, wherein the energy storage system comprises a liquid energy storage system, a heat storage medium of which is molten salt or heat conducting oil, and the molten salt is binary nitrate, ternary nitrate or chloride salt; or a solid state energy storage system, the thermal storage medium of which is a solid state thermal storage medium comprising a metal oxide or silicate.
5. The method according to claim 4, wherein the low-temperature heat source comprises one of an air source heat source, a power generation system waste heat source, an industrial waste heat source, a geothermal heat source and heat released by a condenser by a working medium in a power supply mode, and the heat storage medium with different working temperatures is matched for different low-temperature heat sources to store energy and the working medium with different boiling points.
6. The steam cycle type Carnot battery is characterized by comprising an energy storage system, a heat pump cycle working device connected with the energy storage system through a first condenser and a heat engine cycle working device connected with the energy storage system through a second evaporator;
the heat pump cycle working device comprises a compressor, a first condenser, a throttle valve and a first evaporator, wherein the compressor, the first condenser, the throttle valve and the first evaporator are sequentially connected in series by pipelines along the trend of a working medium and form a loop; the heat pump cycle working device is arranged to realize the compressor heat pump cycle of working medium in an energy storage mode;
the heat engine circulation working device is arranged to realize the steam power circulation of working medium in a power supply mode; the heat engine circulation working device at least comprises a steam turbine and a second evaporator, the heat turbine is used for generating electricity through the external function of the steam turbine, and the working medium exchanges heat with the energy storage system through the isobaric heat absorption of the second evaporator, so that the temperature of the liquid working medium rises and is evaporated into high-temperature high-pressure steam.
7. The steam cycle type carnot battery of claim 6, wherein the heat engine cycle working device comprises a second evaporator, a superheater, a steam turbine, a second condenser and a working medium pump which are sequentially connected in series by pipelines along the trend of the working medium and form a loop, so as to realize the rankine cycle of the working medium in a power supply mode; or (b)
The heat engine circulation working device comprises a second evaporator, a separator, a steam turbine, a mixer, a second condenser, a working medium pump and a heat exchanger which are sequentially connected in series by pipelines along the trend of a working medium to form a loop; the separator comprises an ammonia-rich steam outlet and an ammonia-poor solution outlet, and the ammonia-rich steam outlet is connected with the steam turbine; the mixer is provided with two input ports, wherein one input port is connected with the steam turbine; the heat exchanger is provided with a pipe side and a shell side, and is connected with the working medium pump and the second evaporator through the pipe side; a shell side and a throttle valve of the heat exchanger which are sequentially connected in series along the trend of the working medium are also arranged between the lean ammonia solution outlet of the separator and the other input port of the mixer; in order to realize the kalina cycle of aqueous ammonia solution under the power supply mode.
8. The steam cycle type carnot cell of claim 6, wherein the working medium comprises one of water, an aqueous ammonia solution, and an organic solvent comprising one of hydrocarbons, alcohols, ethers, esters, ketones, aldehydes, phenols, carboxylic acids, amines, glycol derivatives, and heterocyclic compounds.
9. The vapor cycle carnot cell of claim 6 wherein the energy storage system is a liquid energy storage system comprising at least two interconnected thermal storage medium thermal storage vessels having different internal liquid thermal storage medium temperatures or at least one interconnected thermal storage medium thermal storage vessel having a sloped temperature layer with a temperature gradient of the internal liquid thermal storage medium.
CN202310489493.9A 2023-04-28 2023-04-28 Steam circulation type Carnot battery and energy storage method thereof Pending CN116608022A (en)

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