Solid-phase cold storage system for improving cold energy quality

Abstract

The utility model discloses a solid-phase cold storage system for improving cold energy quality. Comprising a liquid air storage unit for liquefying and storing air, a solid-phase cold storage unit for storing cold energy released when high-pressure liquid air is gasified from a liquid state to a gas state, and a solid-phase cold release unit for releasing cold energy stored by a solid-phase packed bed, the front end and the rear end of the liquid air storage unit are connected with the solid-phase cold release unit and the solid-phase cold storage unit in series correspondingly, and the front end of the solid-phase cold release unit is connected with a compressed air stream. According to the solid-phase cold storage system, the re-cooling expansion machine is additionally arranged in the cold release circulation loop in the solid-phase cold storage system, so that the cold energy quality is further improved on the basis of the original cold release quality of a packed bed, and the problems that the cold energy quality is gradually reduced and the loss is large due to the existence of a thermocline in the cold release process of solid-phase cold storage are effectively solved; the liquefaction rate of the system in the energy storage process is guaranteed, and the operation stability of the cold storage system is improved.

Description

Technical Field

[0001] This utility model relates to the field of liquid air energy storage technology, and more specifically to a solid-phase cold storage system for improving the quality of cold energy. Background Technology

[0002] Liquid air energy storage, as a novel physical energy storage technology, is considered a promising solution to support future high-proportion renewable energy power systems due to its significant advantages such as high energy density, long equipment lifespan, good environmental compatibility, and strong geographical adaptability. As a key component of liquid air energy storage systems, the operating characteristics and efficiency of the system play an absolute role in the overall energy efficiency and reliability. Currently, in demonstration projects and research activities, the recognized cryogenic energy storage technologies mainly focus on packed bed energy storage and liquid-phase energy storage, using solid materials such as rocks as storage materials. While liquid-phase energy storage offers high energy storage efficiency, the available storage media are limited. For example, a two-stage liquid-phase energy storage system using methanol and propane can achieve cryogenic storage below -150°C, but its flammable and explosive properties pose significant safety hazards, greatly restricting the application of liquid air energy storage systems in densely populated areas and load centers. Solid-phase cold storage is considered one of the most important cold storage methods for the future development of liquid air energy storage due to its wide availability of materials, long lifespan, safety, and lack of pollution. However, solid-phase cold storage suffers from significant energy loss due to the secondary transfer of cold energy using an intermediate circulation medium, especially in the high-quality portion. Furthermore, the presence of a thermocline results in low overall round-trip efficiency. Therefore, improving the cold energy quality of solid-phase cold storage systems during the cold release process is one of the important directions for the future development of liquid air energy storage systems. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a solid-phase cold storage system for improving the quality of cold energy, overcome the problem of reduced cold storage quality caused by the presence of a thermocline in the solid-phase cold storage system, further improve the quality of cold energy in the release process, and increase the liquefaction rate in the energy storage process.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows.

[0005] A solid-phase cold storage system for improving cold energy quality includes a liquid air storage unit for liquefying and storing air, a solid-phase cold storage unit for storing the cold energy released when high-pressure liquid air is vaporized from liquid to gas, and a solid-phase cold release unit for releasing the cold energy stored in a solid-phase packed bed. The front and rear ends of the liquid air storage unit are connected in series with the solid-phase cold release unit and the solid-phase cold storage unit, respectively. The front end of the solid-phase cold release unit is connected to a compressed air stream.

[0006] To further optimize the technical solution, the liquid air storage unit includes a cryogenic throttling valve connected in series with the solid phase cooling unit to reduce the pressure of the high-pressure liquid air. The downstream end of the cryogenic throttling valve is connected to a liquid air storage tank for storing liquid air via a gas-liquid separator.

[0007] The technical solution is further optimized. The solid-phase cold storage unit includes a cryogenic pump connected in series at the rear end of the liquid air storage unit for pressurizing the liquid air and an evaporator for vaporizing the liquid air. The heat exchange hot end of the evaporator is connected to a solid-phase packed bed through a cold storage fan, and a heater is connected to the rear end of the evaporator.

[0008] To further optimize the technical solution, a cold storage inlet control valve is installed on the pipeline between the solid-phase packed bed and the evaporator, and a cold storage fan inlet control valve and a cold storage fan outlet control valve are respectively installed on the pipelines at both ends of the cold storage fan.

[0009] The technical solution is further optimized. The solid-phase cooling unit includes a liquefaction main heat exchanger connected to the liquid air storage unit. A conventional cooling circulation loop and a cooling energy quality improvement circulation loop are set between the liquefaction main heat exchanger and the solid-phase packed bed.

[0010] Further optimizing the technical solution, the conventional cooling circulation loop includes a cooling fan inlet control valve, a cooling fan and a cooling fan outlet control valve connected between the heat exchange hot end of the liquefaction main heat exchanger and the solid packed bed, and a recooling expander bypass control valve connected between the heat exchange cold end of the liquefaction main heat exchanger and the solid packed bed.

[0011] Further optimizing the technical solution, the improved cold energy quality circulation loop includes a release compressor inlet control valve, a release compressor and a release compressor outlet control valve connected between the heat exchange hot end of the liquefaction main heat exchanger and the solid packed bed, and a recooling expander inlet control valve, a recooling expander and a recooling expander outlet control valve connected between the heat exchange cold end of the liquefaction main heat exchanger and the solid packed bed.

[0012] The technological advancements achieved by this utility model are as follows, due to the adoption of the above technical solutions.

[0013] This utility model provides a solid-phase cold storage system for improving cold energy quality. By adding a recooling expander to the cold release cycle loop of the solid-phase cold storage system, the cold energy quality is further improved on the basis of the original cold release quality of the packed bed. It effectively solves the problem of gradual decrease in cold energy quality and large energy loss caused by the presence of the thermocline during the cold release process of solid-phase cold storage, ensures the liquefaction rate of the energy storage system, improves the operational stability of the cold storage system, and provides a reference for the widespread application of solid-phase cold storage systems. Attached Figure Description

[0014] Figure 1This is a schematic diagram of the structure of this utility model.

[0015] Among them: 101. Cryogenic throttling valve, 102. Gas-liquid separator, 103. Liquid air storage tank, 201. Cryogenic pump, 202. Evaporator, 203. Packed bed cold storage inlet control valve, 204. Solid phase packed bed, 205. Cold storage fan inlet control valve, 206. Cold storage fan, 207. Cold storage fan outlet control valve, 301. Liquefaction main heat exchanger, 302. Release fan inlet control valve, 303. Release fan, 304. Release fan outlet control valve, 305. Recooling expander bypass control valve, 311. Recooling expander inlet control valve, 312. Recooling expander, 313. Recooling expander outlet control valve, 314. Release compressor inlet control valve, 315. Release compressor, 316. Release compressor outlet control valve. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0017] A solid-phase cold storage system for improving the quality of cold energy, combined with Figure 1 As shown, it includes a liquid air storage unit, a solid-phase cold storage unit, and a solid-phase cold release unit. The front and rear ends of the liquid air storage unit are connected in series with the solid-phase cold release unit and the solid-phase cold storage unit, respectively. The front end of the solid-phase cold release unit is connected to a compressed air stream, and the rear end of the solid-phase cold storage unit is connected to a heater for heating the air.

[0018] The liquid air storage unit is used to liquefy and store air, and includes a cryogenic throttle valve 101, a gas-liquid separator 102, and a liquid air storage tank 103. The cryogenic throttle valve 101 is connected in series with a solid-phase cooling unit to reduce the pressure of the high-pressure liquid air. The gas-liquid separator 102 and the liquid air storage tank 103 are sequentially arranged at the rear end of the cryogenic throttle valve 101. The liquid air storage tank is used to store liquid air. The cryogenic throttle valve 101 can be replaced by a cryogenic liquid expander.

[0019] When the liquid air storage unit is in operation, the high-pressure liquid air from the solid phase cooling unit is depressurized by the low-temperature throttling valve 101 and a portion of the low-temperature gaseous air is flashed out. The lower-pressure liquid air flows into the liquid air storage tank 103 after passing through the gas-liquid separator 102. Correspondingly, the low-temperature gaseous air flows into the solid phase cooling unit as a return flow after passing through the gas-liquid separator 102 to release the cooling capacity.

[0020] The solid-phase cold storage unit is used to store the cold energy released when high-pressure liquid air is vaporized from liquid to gas. It includes a cryogenic pump 201 and an evaporator 202 connected in series at the rear end of the liquid air storage tank 103. A heater is connected at the rear end of the evaporator 202. The cryogenic pump 201 is used to pressurize the liquid air, and the evaporator 202 is used to vaporize the liquid air to release the cold energy. After the cold energy is released, it flows into the heater at the rear end to continue to heat up. The heat exchange hot end of the evaporator 202 is connected to a solid-phase packed bed 204 through a cold storage fan 206. The number of solid-phase packed beds 204 is not limited to one, but is determined according to the capacity of the liquid air energy storage system.

[0021] A packed bed cold storage inlet control valve 203 is installed on the pipeline between the solid packed bed 204 and the evaporator 202, and a cold storage fan inlet control valve 205 and a cold storage fan outlet control valve 207 are respectively installed on the pipelines on both sides before and after the cold storage fan 206.

[0022] During the cold storage process, the cold storage circulation medium flows from bottom to top in the solid-phase packed bed 204. The cold storage circulation medium flows into the cold storage fan 206 through the cold storage fan inlet control valve 205. After being pressurized by the cold storage fan 206, it enters the evaporator 202 through the cold storage fan outlet control valve 207 to exchange heat with the liquid air from the low-temperature pump 201. After absorbing cold energy, the temperature decreases. The low-temperature cold storage circulation medium flows into the solid-phase packed bed 204 from the bottom after passing through the packed bed cold storage inlet control valve 203 and exchanges heat with the solid-phase cold storage medium therein. After transferring the cold energy to the solid-phase cold storage medium, it flows out from the top of the solid-phase packed bed 204, passes through the cold storage fan inlet control valve 205, and enters the cold storage fan 206 to complete the cold storage cycle.

[0023] The solid-phase cooling unit is used to release the cold energy stored in the solid-phase packed bed 204. It includes a liquefaction main heat exchanger 301 and two circulation loops located between the liquefaction main heat exchanger 301 and the solid-phase packed bed 204, namely a conventional cooling circulation loop and a cooling circulation loop for improving the quality of cold energy.

[0024] The conventional cooling circulation loop includes a cooling fan inlet control valve 302, a cooling fan 303, and a cooling fan outlet control valve 304 connected between the heat exchange hot end of the liquefaction main heat exchanger 301 and the solid packed bed 204, and a recooling expander bypass control valve 305 connected between the heat exchange cold end of the liquefaction main heat exchanger 301 and the solid packed bed 204.

[0025] During the operation of the conventional cold release cycle, the cold storage circulation medium flows from top to bottom in the solid packed bed 204. The circulation medium flows out from the bottom of the solid packed bed 204, passes through the recooling expander bypass control valve 305, and enters the liquefaction main heat exchanger 301 to release cold energy. After the temperature rises, it flows into the cold release fan 303 after passing through the cold release fan inlet control valve 302 and is pressurized. Then, it flows into the top of the packed bed through the cold release fan outlet control valve 304 to complete the conventional cold release cycle.

[0026] The cooling energy quality improvement cooling cycle includes a cooling compressor inlet control valve 314, a cooling compressor 315 and a cooling compressor outlet control valve 316 connected between the heat exchange hot end of the liquefaction main heat exchanger 301 and the solid packed bed 204, and a recooling expander inlet control valve 311, a recooling expander 312 and a recooling expander outlet control valve 313 connected between the heat exchange cold end of the liquefaction main heat exchanger 301 and the solid packed bed 204.

[0027] When the cold energy quality improvement cooling cycle is running, the low-temperature circulating cold storage medium flows out from the bottom of the solid-phase packed bed 204, passes through the recooling expander inlet control valve 311, enters the recooling expander 312 for expansion and cooling, passes through the recooling expander outlet control valve 313, and flows into the liquefaction main heat exchanger 301 to release cold energy. After the temperature rises, it passes through the cold release compressor inlet control valve 314 and flows into the cold release compressor 315 for pressurization, and then flows through the cold release compressor outlet control valve 316 into the top of the packed bed to complete the cold energy quality improvement cooling cycle.

Claims

1. A solid-phase cold storage system for improving the quality of cold energy, characterized in that: It includes a liquid air storage unit for liquefying and storing air, a solid-phase cold storage unit for storing the cold energy released when high-pressure liquid air is vaporized from liquid to gas, and a solid-phase cold release unit for releasing the cold energy stored in the solid-phase packed bed. The front and rear ends of the liquid air storage unit are connected in series with the solid-phase cold release unit and the solid-phase cold storage unit, respectively. The front end of the solid-phase cold release unit is connected to a compressed air stream.

2. A solid-phase cold storage system for improving cold energy quality according to claim 1, characterized in that: The liquid air storage unit includes a cryogenic throttle valve (101) connected in series with the solid phase cooling unit to reduce the pressure of the high-pressure liquid air. The downstream end of the cryogenic throttle valve (101) is provided with a liquid air storage tank (103) for storing liquid air through a gas-liquid separator (102).

3. A solid-phase cold storage system for improving cold energy quality according to claim 1, characterized in that: The solid-phase cold storage unit includes a cryogenic pump (201) connected in series at the rear end of the liquid air storage unit for pressurizing the liquid air and an evaporator (202) for vaporizing the liquid air. The heat exchange end of the evaporator (202) is connected to a solid-phase packed bed (204) through a cold storage fan (206), and a heater is connected at the rear end of the evaporator (202).

4. A solid-phase cold storage system for improving cold energy quality according to claim 3, characterized in that: A packed bed cold storage inlet control valve (203) is installed on the pipeline between the solid packed bed (204) and the evaporator (202), and a cold storage fan inlet control valve (205) and a cold storage fan outlet control valve (207) are respectively installed on the pipelines at both ends of the cold storage fan (206).

5. A solid-phase cold storage system for improving cold energy quality according to claim 3, characterized in that: The solid-phase cooling unit includes a liquefaction main heat exchanger (301) connected to the liquid air storage unit. A conventional cooling circulation loop and a cooling energy quality improvement circulation loop are provided between the liquefaction main heat exchanger (301) and the solid-phase packed bed (204).

6. A solid-phase cold storage system for improving cold energy quality according to claim 5, characterized in that: The conventional cooling circulation loop includes a cooling fan inlet control valve (302), a cooling fan (303), and a cooling fan outlet control valve (304) connected between the heat exchange hot end of the liquefaction main heat exchanger (301) and the solid packed bed (204), and a recooling expander bypass control valve (305) connected between the heat exchange cold end of the liquefaction main heat exchanger (301) and the solid packed bed (204).

7. A solid-phase cold storage system for improving cold energy quality according to claim 5, characterized in that: The improved cold energy quality circulation loop includes a release compressor inlet control valve (314), a release compressor (315), and a release compressor outlet control valve (316) connected between the heat exchange hot end of the liquefaction main heat exchanger (301) and the solid packed bed (204), and a recooling expander inlet control valve (311), a recooling expander (312), and a recooling expander outlet control valve (313) connected between the heat exchange cold end of the liquefaction main heat exchanger (301) and the solid packed bed (204).

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