CN115164628A - Cryogenic liquid air energy storage system coupled with electric heat storage device - Google Patents

Cryogenic liquid air energy storage system coupled with electric heat storage device Download PDF

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Publication number
CN115164628A
CN115164628A CN202210805956.3A CN202210805956A CN115164628A CN 115164628 A CN115164628 A CN 115164628A CN 202210805956 A CN202210805956 A CN 202210805956A CN 115164628 A CN115164628 A CN 115164628A
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China
Prior art keywords
air
tank
heat storage
cold
heat
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CN202210805956.3A
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Chinese (zh)
Inventor
丁玉龙
金翼
张童童
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Kelvin Thermal Technology Co ltd
Jiangsu Jinhe Energy Technology Co ltd
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Kelvin Thermal Technology Co ltd
Jiangsu Jinhe Energy Technology Co ltd
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Priority to CN202210805956.3A priority Critical patent/CN115164628A/en
Publication of CN115164628A publication Critical patent/CN115164628A/en
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    • 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
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F27/00—Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus
    • F28F27/006—Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus specially adapted for regenerative heat-exchange apparatus
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/14—Thermal energy storage

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Separation By Low-Temperature Treatments (AREA)

Abstract

The invention discloses a cryogenic liquid air energy storage system coupled with an electric heat storage device, which comprises a booster set, a liquefied cold box, a liquid-air separation tank, an evaporator, a cold storage tank, a reheater, an expansion generator set and an electric heat storage device, wherein the booster set is connected with the liquid-air separation tank; the booster set adopts off-peak electricity to drive to pressurize the air, and the output end of the booster set is connected with the hot end inlet of the liquefied cold box; the hot end outlet of the liquefaction cold box is connected to the liquid-air separation tank through a pipeline; the cold end inlet and outlet of the liquefaction cold box are respectively connected to the cold storage tank; the rear end of the liquid-air separation tank is connected to the evaporator and exchanges heat with the cold accumulation tank through the evaporator; the rear end of the evaporator is connected to a reheater, and the rear end of the reheater is connected to an expansion generator set; the expansion generator set comprises a group of expansion generators and a group of heaters arranged among the expansion generators at all levels, the hot end of each heater is connected to the electric heat storage device through a pipeline, and the air entering the heaters is heated by the heat energy in the electric heat storage device.

Description

Cryogenic liquid air energy storage system coupled with electric heat storage device
Technical Field
The invention belongs to the field of cryogenic liquid air energy storage, and particularly relates to a cryogenic liquid air energy storage system of a coupling electric heat storage device.
Background
The cryogenic liquid air energy storage technology is proposed by british high-dimensional company in 2007, and is used as a set of independent energy storage device for peak shaving of power station and stable access of renewable energy sources, and the system is similar to a compressed air energy storage technical route, air compression refers to a high-temperature and high-pressure state, heat is stored, in order to effectively improve storage density, high-pressure air is converted into liquid air through a low-temperature expansion process to be stored, and an energy storage process is achieved. When energy is released, liquid air is evaporated into high-pressure air and then heated by high-temperature heat energy stored at the front end, namely, the expander is powered to generate electricity in a high-temperature state, and the whole energy storage process is completed.
However, for an independent system, the energy efficiency of the cryogenic liquid air energy storage system is not higher than 50-55% as a whole, and in order to improve the energy efficiency of the system, a mode of coupling an external heat source or cold source (such as photo-thermal energy, waste heat, LNG cold energy and the like) is adopted in many schemes to improve the efficiency, but the whole energy efficiency of the system is not comprehensively considered, the application scenario is greatly limited, and the popularization is poor.
The main problems are as follows:
(1) Cryogenic storage and compressed air storage to account for overall system efficiency, designs typically increase the temperature of the expander interstage heating, and this process typically removes the compressor interstage refrigeration to achieve higher exit temperatures, on the order of 300 ℃. Because of the restriction factors of the thermodynamic conversion problem in the compression process of the compressor, the processing difficulty of the compressor and the like, the temperature of the air at the outlet of the compressor needs to reach about 300 ℃, the thermodynamic conversion efficiency is too low under the condition of higher temperature, the manufacturing cost of the compressor is sharply increased,
(2) The storage and release process of compression heat involves the heat transfer, and the heat exchanger end difference is great, can cause the loss of energy, reduces the design of end difference, though can reduce the loss of energy in theory, can cause the heat transfer resistance to rise because heat transfer area is too big in the actual engineering, and the energy loss problem can not obtain fundamental solution.
(3) Because the surplus part still exists after the heat exchange of the compression heat for many times, the energy loss is more, the waste heat grade is lower (the temperature is lower than 100 ℃) due to the fact that the heat energy is used for the power generation process, and the available value is lower.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a technical route for coupling an electric heating high-temperature heat storage device and a cryogenic system aiming at the defects of the prior art, and the electric heating high-temperature heat storage device and the cryogenic system are combined to realize the effective utilization of a high-temperature heat source, so that the utilization value of heat energy is improved.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a cryogenic liquid air energy storage system coupled with an electric heat storage device comprises a booster set, a liquefaction cold box, a liquid-air separation tank, an evaporator, a cold storage tank, a reheater, an expansion generator set and the electric heat storage device;
the pressurizing unit is driven by off-peak electricity to pressurize air, the output end of the pressurizing unit is connected with the hot end inlet of the liquefied cold box, and the pressurized air is sent into the liquefied cold box to be cooled; the hot end outlet of the liquefaction cold box is connected to the liquid-air separation tank through a pipeline, and the cooled pressurized air is sent into the liquid-air separation tank for separation; the inlet and the outlet of the cold end of the liquefaction cold box are respectively connected to the cold storage tanks, and the cold energy stored in the cold storage tanks is used for cooling the pressurized air entering the liquefaction cold box;
the rear end of the liquid-air separation tank is connected to the evaporator, the liquid-air separation tank exchanges heat with the cold accumulation tank through the evaporator, and cold energy in the cold accumulation tank is supplemented by liquid air; the rear end of the evaporator is connected to a reheater, the rear end of the reheater is connected to an expansion generator set, and the heated high-pressure air enters the expansion generator set to be used for work and power generation;
the expansion generator set comprises a group of expansion generators and a group of heaters arranged among all stages of expansion generators, the hot ends of the heaters are connected to the electric heat storage device through pipelines, and air entering the heaters is heated by heat energy in the electric heat storage device and then sent into all stages of expansion generators.
The electric heating heat storage device comprises an electric heating heat storage tank, an in-tank heat exchanger, a heat storage module, an electric heating element, an out-tank circulating pipe and an out-tank fan;
the electric heating heat storage tank is filled with heat transfer working medium; the heat storage module adopts heat storage materials such as a phase change heat storage material, a sensible heat storage material, a phase change latent heat storage material and the like; the electric heating element and the heat storage module are distributed at intervals, and the electric heating element is converted into heat energy by utilizing valley electricity or wind electricity and stored in the heat storage module formed by the phase-change heat storage material; two ends of the tank external circulation pipe are respectively connected to the bottom and the top of the electric heat storage tank; the external fan is arranged on the external circulating pipe, and the external fan is used for strengthening the flow of the heat transfer working medium in the tank and enhancing the heat exchange efficiency;
and the heat exchanger inlet and the heat exchanger outlet of the heat exchanger in the tank are respectively connected to each stage of heater of the expansion generator set to heat the air entering the heater.
Further, heat conduction enhancement particles are added into the electric heat storage tank, and the heat conduction enhancement particles comprise, but are not limited to, siO 2 Particles, mgO particles or Al 2 O 3 The addition amount of the particles is 0.5-10% of the volume in the tank, and the particle size is 0.1-10 mm; air distribution net is installed to the bottom of electric heat accumulation jar, and jar mouthful baffle is installed at the bottom top of electric heat accumulation jar, prevents that the granule from getting into to destroy the fan in the pipeline. It should be noted that the heat source may also be other high-temperature heat sources, such as steam, solar photo-thermal, etc., which is also beneficial to the efficient utilization of heat energy.
The upper part and the bottom of the electric heating element are both provided with high-temperature and high-pressure insulators, and the insulators are used for preventing high-voltage electric leakage and other safety risks.
Furthermore, a compressor unit is arranged at the front end of the booster unit; the compressor unit pre-compresses external air through low-valley electric driving, and then sends the pre-compressed air to the booster unit for further compression.
Furthermore, inter-compressor coolers are arranged among the compressors of each stage of the compressor unit; a compression-increase inter-group cooler is arranged between the compressor unit and the booster unit; an inter-supercharger cooler is arranged between each stage of superchargers of the supercharger unit; the outlet end of the booster set is provided with a booster outlet cooler; the cold ends of the inter-compressor cooler, the inter-compression-increase cooler, the inter-supercharger cooler and the supercharger outlet cooler are respectively connected to a cold water tank and a hot water tank, and the heat energy of the pressurized air is stored in water by utilizing the coolers for industrial or civil heat supply.
Further, an expansion refrigerator is connected to the outside of the liquefaction cold box; the inlet end of the expansion refrigerator is connected with the liquefaction cold box, the outlet end of the expansion refrigerator is connected with the air separation tank in parallel through a pipeline, then the outlet end of the expansion refrigerator and the air separation tank are connected to the cold end of the liquefaction cold box together, and the outlet of the expansion refrigerator is connected to the cooler between the compression and increase units through the other end of the liquefaction cold box. And a part of air cooled in the liquefaction cold box is pumped out and enters the expansion refrigerator, the air is mixed with unliquefied gaseous air in the air separation tank after expansion and then enters the liquefaction cold box for refrigeration 300 to serve as a cold source, the cold source exchanges heat with high-pressure air entering the outlet of the booster set, the air is heated to a normal temperature state, and then the air is mixed with air at the outlet of the compressor set and then is sent to the booster set for circulation.
Specifically, a throttling valve is arranged on a pipeline between the hot end outlet of the liquefaction cold box and the liquid-air separation tank; the air is quickly converted into liquid air after being expanded by a throttle valve and enters a liquid-air separation tank; the rear end of the liquid-air separation tank is connected with a liquid-air storage tank; the rear end of the liquid air storage tank is connected to the evaporator, and a low-temperature pump is arranged on a pipeline between the liquid air storage tank and the evaporator. The steam is pressurized by a low-temperature pump and then sent into a steam device, and the evaporator is heated to normal-temperature high-pressure air by a circulating working medium taking air as a carrier.
Specifically, a group of inlet and outlet of the cold storage tank is connected to the liquefaction cold box to provide cold energy for the liquefaction cold box; the other group of inlets and outlets of the cold storage tank are connected to the evaporator, and cold energy of liquid air is brought into the cold storage tank through the circulating working medium for storage and is used as an external cold source required by the liquefaction cold box; and a cold accumulator fan is arranged on an outlet pipeline of the cold accumulation tank.
Preferably, in the expansion generator set, each stage of corresponding heater is arranged in front of each stage of expansion generator, the hot end of each stage of heater is connected in parallel to the electric heat storage device through a pipeline, and air entering the heater is heated by heat energy in the electric heat storage device and then is sent to each stage of expansion generator to be used for work generation.
Preferably, each stage of heater and the corresponding expansion generator are sequentially connected in series, and finally return to the reheater through a circulating pipeline, the normal-temperature high-pressure air coming out of the evaporator is heated, and the heat is recovered and then discharged, and the heat can be further used as heat for residents or industries.
Has the advantages that:
(1) The invention combines the cryogenic energy storage system and the high-temperature heat storage device, namely, a high-temperature heat source can be provided for the cryogenic liquid air energy storage system to ensure the overall energy conversion efficiency of the system, and meanwhile, the equipment arrangement is flexible and is not limited by geographical positions and spatial layout, so that the invention has good flexibility. The compressor converts valley electricity into high-pressure air internal energy and high-temperature heat and stores the high-pressure air and the high-temperature heat in other tank bodies respectively, the high-pressure air is converted into cryogenic liquid air (below minus 160 ℃) through a liquefaction expansion process and stored, and the heat energy is stored in a heat storage working medium (such as pressurized water, heat conduction oil and molten salt) in a high-temperature mode through a heat exchange device. The device can adopt multiple technical paths of sensible heat storage, phase change latent heat storage and the like by introducing a high energy density form of electric heat storage, the overall economy of the device is improved, the overall energy efficiency of the device is guaranteed, meanwhile, the dependence on external energy is extremely low, and the device is a set of complete and independent energy storage system.
(2) The compression heat is not stored in a high-temperature form of about 300 ℃, the operation efficiency of the process of the compressor is facilitated by adopting the conventional method, the conversion efficiency of energy can be effectively improved by adopting the high-temperature heat energy stored by the independent heat storage device for heating during expansion, and the overall utilization rate of the energy is improved by the scheme. The heat release temperature of heat storage is increased to 600-1000 ℃, so that the compressor (including the supercharger) is always kept in a low-temperature high-efficiency operation state, working air with high temperature and high pressure can be obtained at the inlet of the expander, the power generation efficiency is improved, the operation efficiency of the whole system is improved, the whole system efficiency is superior to that of an independent liquid air energy storage system, and compared with the heat storage technology of high-temperature heat conduction oil or molten salt, the whole equipment cost is more advantageous.
Drawings
The foregoing and/or other advantages of the invention will become further apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings.
Fig. 1 is a schematic diagram of the overall structure of the system of the present invention.
FIG. 2 is a schematic view of an electrothermal heat storage device of the present invention.
FIG. 3 shows the electrical efficiency of the whole system under different electrothermal heating conditions.
Fig. 4 is a graph of unit liquid-air power generation amount with temperature change.
Wherein each reference numeral represents:
100 compressor trains; 101 a first-stage compressor; 102 a secondary compressor; 103 inter-compressor coolers; 200 of a booster set; 201 a first-stage supercharger; 202, a second-stage supercharger; 203 compression-add inter-group cooler; 204 a booster intercooler; 205 supercharger outlet cooler; 300 a liquefaction cold box; 301 an expansion refrigerator; 401 a cold water tank; 402 a hot water tank; 500 liquid-air separation tank; 501 a throttle valve; 502 liquid-air reservoir; 503 a cryopump; 600 an evaporator; 700 a regenerator; 701 a regenerator fan; 800 a reheater; 900 expanding the generating set; 901 a primary expansion generator; 902 a secondary expansion generator; 903 three-stage expansion generator; 904 a four stage expansion generator; 905 a first-stage heater; 906 a secondary heater; 907 a three-level heater; a 908 four stage heater;
10 an electrothermal heat storage device; 11 an electric heat storage tank; 12 in-tank heat exchangers; 12-1 heat exchanger inlet; 12-2 heat exchanger outlet; 13 thermally conductive reinforcing particles; 14 a heat storage module; 15 an electrothermal heating element; 16 insulators; 17, a wind distribution net; 18 tank external fan; 19 tank external circulation pipe; 20 tank mouth baffles.
Detailed Description
The invention will be better understood from the following examples.
The structures, proportions, and dimensions shown in the drawings and described in the specification are for understanding and reading the present disclosure, and are not intended to limit the scope of the present disclosure, which is defined in the claims, and are not essential to the skilled in the art. In addition, the terms "upper", "lower", "front", "rear" and "middle" used in the present specification are for clarity of description, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the relative positions may be changed or adjusted without substantial technical changes.
Referring to fig. 1, the cryogenic liquid air energy storage system coupled with an electric heat storage device of the present invention includes a booster unit 200, a liquefied cold box 300, a liquid-air separation tank 500, an evaporator 600, a cold storage tank 700, a reheater 800, an expansion generator unit 900, and an electric heat storage device 10.
Wherein, the booster set 200 adopts off-peak electricity to drive to pressurize the air, the output end is connected with the hot end inlet of the liquefied cold box 300, and the pressurized air is sent into the liquefied cold box 300 to be cooled; the hot end outlet of the liquefaction cold box 300 is connected to the liquid-air separation tank 500 through a pipeline, and the cooled pressurized air is sent into the liquid-air separation tank 500 for separation; the cold end inlet and outlet of the liquefaction cold box 300 are respectively connected to the cold accumulation tank 700, and the pressurized air entering the liquefaction cold box 300 is cooled by using the cold energy stored in the cold accumulation tank 700.
The rear end of the liquid-air separation tank 500 is connected to the evaporator 600, exchanges heat with the cold storage tank 700 through the evaporator 600, and supplements cold energy in the cold storage tank 700 by using liquid air; the rear end of the evaporator 600 is connected to the reheater 800, the rear end of the reheater 800 is connected to the expansion generator set 900, and the heated high-pressure air enters the expansion generator set 900 to perform work and power generation.
The expansion generator set 900 includes a set of expansion generators and a set of heaters disposed between the expansion generators, the hot end of each heater is connected to the electrothermal heat storage device 10 through a pipeline, and the air entering the heater is heated by the heat energy in the electrothermal heat storage device 10 and then sent to the expansion generators.
As shown in fig. 2, the electrothermal heat storage device 10 includes an electrothermal heat storage tank 11, an in-tank heat exchanger 12, a heat storage module 14, an electrothermal heating element 15, an out-tank circulation pipe 19, and an out-tank fan 18.
Wherein, the electric heat storage tank 11 is filled with heat transfer working medium; the heat storage module 14 adopts a phase-change heat storage material; the electrothermal heating element 15 and the heat storage module 14 are distributed at intervals, and the electrothermal heating element 15 is converted into heat energy by utilizing valley electricity or wind electricity and stored in the heat storage module 14 formed by phase-change heat storage materials; two ends of the tank external circulation pipe 19 are respectively connected with the bottom and the top of the electric heat storage tank 11; the out-of-tank fan 18 is mounted on the out-of-tank circulation pipe 19, and the out-of-tank fan 18 is used for strengthening the flow of the heat transfer working medium in the tank and enhancing the heat exchange efficiency.
The heat exchanger inlet 12-1 and the heat exchanger outlet 12-2 of the in-tank heat exchanger 12 are respectively connected to each stage of heater of the expansion generator set 900, and heat air entering the heater.
In the invention, siO is also added in the electric heat storage tank 11 2 The heat conduction enhanced particles 13, the addition amount of the heat conduction enhanced particles 13 is 0.5% -10% of the volume in the tank, and the particle size is 0.1 mm-10 mm; an air distribution net 17 is installed at the bottom of the electric heating heat storage tank 11, and a tank opening baffle 20 is installed at the top of the bottom of the electric heating heat storage tank 11 to prevent particles from entering a pipeline to damage a fan.
The top and bottom of the electric heating element 15 are provided with high-temperature and high-pressure insulators 16, and the insulators 16 are used for preventing high-pressure electric leakage and other safety risks.
As shown in fig. 1, a compressor unit 100 is further provided at the front end of the booster unit 200; the compressor assembly 100 pre-compresses the external air by a valley electric drive and then feeds the pre-compressed air into the booster assembly 200 for further compression.
The compressor train 100 includes a first-stage compressor 101 and a second-stage compressor 102, with an inter-compressor cooler 103 disposed between each stage of the compressors. A compression-increase inter-group cooler 203 is provided between the compressor unit 100 and the supercharger unit 200.
The booster train 200 includes a first stage booster 201 and a second stage booster 202. An inter-supercharger cooler 204 is arranged between each stage of supercharger; the outlet end of the booster set 200 is provided with a booster outlet cooler 205; cold ends of the inter-compressor cooler 103, the compression-increase inter-group cooler 203, the inter-supercharger cooler 204 and the supercharger outlet cooler 205 are connected to a cold water tank 401 and a hot water tank 402, respectively, and the heat energy of the pressurized air is stored in water by using the coolers for industrial or domestic heating.
With reference to fig. 1, an expansion refrigerator 301 is further connected to the outside of the liquefaction cold box 300; the inlet end of the expansion refrigerator 301 is connected with the liquefaction cold box 300, the outlet end of the expansion refrigerator is connected with the air separation tank 500 in parallel through a pipeline, and then the outlet end of the expansion refrigerator and the air separation tank are connected to the cold end of the liquefaction cold box 300 together, and are connected to the compression-increase inter-group cooler 203 through the outlet at the other end of the liquefaction cold box 300. A part of air cooled in the liquefaction cold box 300 is pumped out and enters the expansion refrigerator 301, the air is mixed with non-liquefied gaseous air in the air separation tank 500 after expansion and then enters the liquefaction cold box for refrigeration 300 to serve as a cold source, the cold source exchanges heat with high-pressure air entering the outlet of the booster set 200, the air is heated to a normal temperature state, and then the air is mixed with air at the outlet of the compressor set 100 and then is sent to the booster set 200 for circulation.
A throttling valve 501 is arranged on a pipeline between the outlet of the hot end of the liquefied cold box 300 and the liquid-air separation tank 500; the air is quickly converted into liquid air after being expanded by a throttle valve 501 and enters a liquid-air separation tank 500; the rear end of the liquid-air separation tank 500 is connected with a liquid-air storage tank 502; the rear end of the liquid-air storage tank 502 is connected to the evaporator 600, and a low-temperature pump 503 is arranged on a pipeline between the liquid-air storage tank 502 and the evaporator 600. The steam is pressurized by a low-temperature pump 503 and then sent into a steam device 600, and the steam device 600 is heated to normal temperature and high pressure air by a circulating working medium taking air as a carrier.
A set of inlets and outlets of the cold accumulation tank 700 are connected to the liquefaction cold box 300 to provide cold energy for the liquefaction cold box 300; the other set of inlet and outlet of the cold storage tank 700 is connected to the evaporator 600, and the cold energy of the liquid air is brought into the cold storage tank 700 through the circulating working medium for storage and is used as an external cold source required by the liquefaction cold box 300; and a cold accumulator fan 701 is arranged on an outlet pipeline of the cold accumulation tank 700.
The expansion generator set 900 includes a first-stage expansion generator 901, a second-stage expansion generator 902, a third-stage expansion generator 903, and a fourth-stage expansion generator 904, which are four stages in total. The expansion generators are provided with corresponding heaters, which include a first-stage heater 905, a second-stage heater 906, a third-stage heater 907 and a fourth-stage heater 908. The hot ends of the heaters are connected in parallel to the electrothermal heat storage device 10 through pipelines, and the air entering the heaters is heated by the heat energy in the electrothermal heat storage device 10 and then sent to the expansion generators at all levels for work generation.
The heaters are sequentially connected in series with the corresponding expansion generators, and finally return to the reheater 800 through a circulation pipeline, so that the normal-temperature high-pressure air from the evaporator 600 is heated, and the heat is discharged after being recovered, and can be further used as heat for residents or industries.
With reference to fig. 1, the overall operation and principle of the system of the present invention are as follows:
the valley electricity drives the two-stage compressor, and compresses the outside air to about 8 atmospheres, configures the inter-compressor cooler 103 and cools the air from-150 ℃ to normal temperature, the other end of the inter-compressor cooler 103 is water of about 10 atmospheres, and stores the heat energy at about-130 ℃. The normal temperature pressurized air after the compressor is out is mixed with the air fed back by the rear end liquefaction cold box 300 and then is sent into the supercharger, the supercharger is also driven by valley electricity, the air with 8 atmospheric pressures is pressurized to about 60 atmospheric pressures, the air is cooled to the high pressure normal temperature in an interstage cooling mode like the compressor, the heat is stored in pressurized water at the temperature of 130 ℃, and the supercharger can be used for industrial or civil heat supply.
The high-pressure normal-temperature air at the outlet enters the liquefied cold box 300 and is further cooled, the cold energy comes from the cold energy stored in the cold accumulator 700 and the cold energy brought by high-pressure expansion refrigeration, a part of cooled air is pumped out and enters the expansion refrigerator 301, the high-pressure air is expanded to about 8 atmospheric pressures, and the high-pressure air is mixed with the low-temperature air returned by the liquid-air separation tank 500 after the temperature reaches minus 160 ℃ and enters the cold box for cooling the high-pressure air at the outlet of the supercharger.
The temperature of the air cooled in the expansion refrigerator 301 is about-160 ℃,60 atmospheres, the air is expanded by the throttle valve 501 and then is rapidly converted into liquid air (-162 ℃,8 atmospheres), the liquid air enters the air separation tank 500, the unliquefied gaseous air is mixed with the low-temperature air at the outlet of the expansion refrigerator 301 and then enters the liquefaction cold box for refrigeration 300, and the liquefied gaseous air is heated to the normal temperature by the high-pressure air at the outlet of the supercharger and then is mixed with the air at the outlet of the compressor and then is sent to the supercharger for circulation.
Thus, a set of liquefied air energy storage process is completed. The energy release process is as follows.
The stored liquid air with 8 atmospheric pressures and-162 ℃ is pressurized to 120 atmospheric pressure by a low-temperature pump 503 and then sent into a steam device 600, and the evaporator 600 is heated to normal-temperature high-pressure air by a circulating working medium taking air as a carrier. The cold energy of the liquid air is brought into the cold accumulator 700 through a circulating working medium (such as air) to be stored, and is used as an external cold source required by the liquefaction cold box.
The normal-temperature and high-pressure (120 atm, normal-temperature) air coming out of the evaporator 600 is subjected to heat exchange with the high-temperature air at the outlet of the expansion generator 900 through the reheater 800, and is heated to a high temperature (the heating temperature is 300 ℃ lower than the set temperature of the electrothermal heat storage device 10), the high-temperature and high-pressure air enters the heater to exchange heat with the heat in the heat storage boiler, and is heated to a target temperature (such as 600,800,1000 in the embodiment), the heated high-pressure air enters the expansion generator 900 to perform work power generation, and the temperature and the pressure of the air are correspondingly reduced. And after each reduction, the air enters the heater again to be heated, namely, the high-temperature state, and the process is circulated for four times until the air pressure is reduced to be close to the normal pressure state, and then the air is discharged, enters the reheater 800 to recover heat and then is discharged. The hot water stored in the front section can be directly used for residential or industrial heat (about 130 ℃) without using the hot water.
In the energy storage process, the compressor and the supercharger both keep an interstage cooling system, so that the energy conversion efficiency of the compressor is improved, and the energy is saved in the compression process. After calculation and analysis, the power consumption of liquid air of 1kg produced can be reduced to 0.23kwh from 0.28kwh, and the power consumption level in the energy storage process is obviously improved. Another part of the electric energy is used for heating the electric heat storage device, thereby realizing the integral electric energy storage.
In the energy releasing process, the heat energy stored in the electric heat storage device 10 and the liquid air work together to generate electricity, and the external electricity generation amount of the liquid air with the same mass is obviously increased under different heating temperatures, as shown in fig. 3. And from the perspective of heating work, the temperature of the outlet at the tail end of the expander still has the hot air of more than 400 ℃, in order to improve the utilization rate of the hot air of the part, the temperature of the exhaust outlet is led to be higher than the outlet position of the evaporator, and the normal-temperature high-pressure air at the outlet part of the evaporator is heated to the temperature of about 400 ℃, so that the integral utilization rate of the system is ensured.
Like the conclusion of fig. 4 can be obtained by considering the power consumption of the heat storage portion, since the electric heating portion also needs to consume a large amount of electric energy, the electric energy of the portion needs to be considered in the overall calculation of the system, and it can be seen from the figure that the system efficiency is effectively improved, and the overall efficiency can be higher than 60%.
The invention provides a thought and a method for a cryogenic liquid air energy storage system coupled with an electrothermal heat storage device, and a method and a way for realizing the technical scheme are many, the above description is only a preferred embodiment of the invention, and it should be noted that, for a person skilled in the art, a plurality of improvements and decorations can be made without departing from the principle of the invention, and the improvements and decorations should be regarded as the protection scope of the invention. All the components not specified in the present embodiment can be realized by the prior art.

Claims (10)

1. A cryogenic liquid air energy storage system coupled with an electric heat storage device is characterized by comprising a booster unit (200), a liquefaction cold box (300), a liquid-air separation tank (500), an evaporator (600), a cold storage tank (700), a reheater (800), an expansion generator unit (900) and an electric heat storage device (10);
the booster set (200) adopts off-peak electricity to drive to pressurize the air, and the output end of the booster set is connected with the hot end inlet of the liquefaction cold box (300); the hot end outlet of the liquefaction cold box (300) is connected to a liquid-air separation tank (500) through a pipeline; an inlet and an outlet of a cold end of the liquefaction cold box (300) are respectively connected to the cold storage tank (700), and the cold energy stored in the cold storage tank (700) is utilized to cool the pressurized air entering the liquefaction cold box (300);
the rear end of the liquid-air separation tank (500) is connected to the evaporator (600) and exchanges heat with the cold accumulation tank (700) through the evaporator (600); the rear end of the evaporator (600) is connected to a reheater (800), the rear end of the reheater (800) is connected to an expansion generator set (900), and the heated high-pressure air enters the expansion generator set (900) to perform work generation;
the expansion generator set (900) comprises a group of expansion generators and a group of heaters arranged among the expansion generators at all levels, the hot end of each heater is connected to the electric heat storage device (10) through a pipeline, and the heat energy in the electric heat storage device (10) is used for heating the air entering the heater.
2. The cryogenic liquid air energy storage system coupled with an electrothermal heat storage device according to claim 1, wherein the electrothermal heat storage device (10) comprises an electrothermal heat storage tank (11), an in-tank heat exchanger (12), a heat storage module (14), an electrothermal heating element (15), an out-of-tank circulation tube (19), and an out-of-tank fan (18);
the electric heat storage tank (11) is filled with heat transfer working medium; the heat storage module (14) adopts heat storage materials; the electric heating elements (15) and the heat storage modules (14) are distributed at intervals; two ends of the tank external circulation pipe (19) are respectively connected with the bottom and the top of the electric heat storage tank (11); the external fan (18) is arranged on the external circulating pipe (19);
and a heat exchanger inlet (12-1) and a heat exchanger outlet (12-2) of the in-tank heat exchanger (12) are respectively connected to each stage of heater of the expansion generator set (900) to heat air entering the heater.
3. The cryogenic liquid air energy storage system of a coupled electrothermal heat storage device of claim 2, characterized in thatCharacterized in that heat conduction enhanced particles (13) are also added into the electric heat storage tank (11); the heat conduction enhancement particles (13) are SiO 2 Particles, mgO particles or Al 2 O 3 The addition amount of the particles is 0.5-10% of the volume in the tank, and the particle size is 0.1-10 mm; the bottom of the electric heating heat storage tank (11) is provided with an air distribution net (17), and the top of the bottom of the electric heating heat storage tank (11) is provided with a tank opening baffle (20);
the upper part and the bottom of the electric heating element (15) are both provided with high-temperature and high-pressure insulators (16).
4. The cryogenic liquid air energy storage system of the coupled electrothermal heat storage device according to claim 1, wherein a compressor unit (100) is further arranged at the front end of the booster unit (200); the compressor unit (100) pre-compresses external air through valley electric driving, and then sends the pre-compressed air into the booster unit (200) for further compression.
5. The cryogenic liquid air energy storage system coupled with an electrothermal heat storage device according to claim 4, wherein an inter-compressor cooler (103) is arranged between each stage of compressors of the compressor unit (100); a compression-increase inter-group cooler (203) is arranged between the compressor unit (100) and the booster unit (200); an inter-supercharger cooler (204) is arranged between each stage of superchargers of the supercharger unit (200); a supercharger outlet cooler (205) is arranged at the outlet end of the supercharger unit (200); the cold ends of the inter-compressor cooler (103), the compression-increase inter-group cooler (203), the inter-supercharger cooler (204) and the supercharger outlet cooler (205) are connected to a cold water tank (401) and a hot water tank (402), respectively.
6. The cryogenic liquid air energy storage system of the coupled electrothermal heat storage device according to claim 5, wherein an expansion refrigerator (301) is further connected to the outside of the liquefaction cold box (300); the inlet end of the expansion refrigerating machine (301) is connected with the liquefaction cold box (300), the outlet end of the expansion refrigerating machine is connected with the air separation tank (500) in parallel through a pipeline, then the expansion refrigerating machine and the air separation tank are connected to the cold end of the liquefaction cold box (300) together, and the expansion refrigerating machine and the air separation tank are connected to the compression-increase inter-group cooler (203) through the outlet at the other end of the liquefaction cold box (300).
7. The cryogenic liquid air energy storage system of the coupling electrothermal heat storage device according to claim 1, wherein a throttle valve (501) is arranged on a pipeline between a hot end outlet of the liquefied cold box (300) and the liquid-air separation tank (500); the rear end of the liquid-air separation tank (500) is connected with a liquid-air storage tank (502); the rear end of the liquid-air storage tank (502) is connected to the evaporator (600), and a low-temperature pump (503) is arranged on a pipeline between the liquid-air storage tank (502) and the evaporator (600).
8. The cryogenic liquid air energy storage system coupled with an electrothermal heat storage device according to claim 7, wherein one set of inlets and outlets of the cold storage tank (700) is connected to the liquefied cold box (300), and the other set of inlets and outlets of the cold storage tank (700) is connected to the evaporator (600); and a cold accumulator fan (701) is arranged on an outlet pipeline of the cold accumulation tank (700).
9. The cryogenic liquid air energy storage system coupled with an electrothermal heat storage device according to claim 1, wherein in the expansion generator set (900), each stage of corresponding heater is arranged in front of each stage of expansion generator, the hot end of each stage of heater is connected in parallel to the electrothermal heat storage device (10) through a pipeline, and the air entering the heater is heated by the heat energy in the electrothermal heat storage device (10) and then is sent to each stage of expansion generator to be used for generating electricity.
10. The cryogenic liquid air energy storage system of a coupled electrothermal heat storage device according to claim 9, wherein each stage of heater is connected in series with a corresponding stage of expansion generator in sequence, and finally heat is recovered back to the reheater (800) through a circulation pipe.
CN202210805956.3A 2022-07-08 2022-07-08 Cryogenic liquid air energy storage system coupled with electric heat storage device Pending CN115164628A (en)

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CN202210805956.3A CN115164628A (en) 2022-07-08 2022-07-08 Cryogenic liquid air energy storage system coupled with electric heat storage device

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Application Number Priority Date Filing Date Title
CN202210805956.3A CN115164628A (en) 2022-07-08 2022-07-08 Cryogenic liquid air energy storage system coupled with electric heat storage device

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