Coupling system and coupling method for LNG-RG and laes

Abstract

The present invention relates to the technical field of large-scale energy storage. Disclosed are a coupling system and a coupling method for LNG-RG and LAES. The coupling system comprises: an LAES subsystem, an LNG-RG subsystem, and a coupling cold exchange subsystem; in an LAES subsystem charging operating state, ambient air is sequentially compressed by a normal-temperature compressor, the compression heat energy being output to a heat storage tank for storage, then cooled to a deep cryogenic temperature by the coupling cold exchange subsystem, compressed and heated to a shallow cryogenic temperature by a first-stage low-temperature compressor, and cooled to a deep cryogenic temperature by the coupling cold exchange subsystem, so as to enter a next-stage low-temperature compressor; the deep cryogenic temperature is the pressurized outlet temperature in the regasification process of liquefied natural gas, and the shallow cryogenic temperature is the outlet temperature of ambient air after low-temperature compression of the ambient air. The present invention establishes unified management of cold energy of the coupling cold exchange subsystem between the LAES subsystem and the LNG-RG subsystem, and by means of the two temperature compression modes of normal-temperature compression and multi-stage low-temperature compression, uses high-grade cold energy of the LNG-RG subsystem to directly reduce the temperature of the ambient air before entering the low-temperature compressor to the deep cryogenic temperature, thereby reducing power consumption of the air compression process of the LAES subsystem, and further improving the charging and discharging efficiency of the entire LAES subsystem.

Description

A coupling system and coupling method of LNG-RG and LAES

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese Patent Application No. CN202410752033.5, filed on June 12, 2024, the contents of which are incorporated herein in their entirety. TECHNICAL FIELD

[0003] The present application belongs to the technical field of large-scale energy storage, and particularly relates to a coupling system and coupling method of LNG-RG and LAES. BACKGROUND

[0004] Liquid air energy storage (LAES) is a kind of energy storage technology, which absorbs air from the environment using low-cost off-peak electricity, and then cools it until it becomes a liquid for storage. During peak electricity consumption, the liquid air is released and boosted in temperature, and then enters the expander to generate power, achieving off-peak peak use, which plays an important role in grid peak shaving. However, during the charging and discharging processes, there will be a loss of cold energy, and in order to make up for the loss of cold energy, additional electricity is usually consumed to supplement the cold energy, which is costly.

[0005] In recent years, natural gas as a clean energy has steadily increased its share in energy consumption, especially with the improvement of natural gas liquefaction technology and the reduction of LNG (Liquefied Natural Gas) transportation costs, LNG has been widely used and concerned. The receiving terminal of LNG often involves LNG re-gasification (RG) process; a large amount of cold energy is released during the process of LNG warming to natural gas, and the coupling of LAES system and LNG-RG system has great practical application significance and prospect.

[0006] Currently, scholars and manufacturers at home and abroad have proposed several coupling models for LAES and LNG-RG, but the charging and discharging efficiency of the LAES system in the coupling model still needs to be improved. Specifically, the existing technology has the following disadvantages:

[0007] 1. The existing model only considers the coupling of LAES charging condition and LNG-RG, but LNG-RG is often operated in a fluctuating and intermittent manner, and its changes cannot be predicted, so the model does not match the actual situation, and it is difficult to achieve the theoretical effect of the coupling model, so it is difficult to achieve the maximum utilization of LNG-RG cold energy, which leads to low overall charging and discharging efficiency of LAES;

[0008] 2. The existing model only couples the traditional model of LAES with LNG-RG, and there is no targeted optimization for the LAES side, which leads to the fact that the value of the cold energy of LNG-RG is not maximized, and the overall charging and discharging efficiency of LAES still has room for improvement. SUMMARY

[0009] Therefore, one object of the present application is to provide a coupling system of LNG-RG and LAES to maximize the rational use of the wasted cold energy of LNG-RG and solve the problem of low charging and discharging efficiency of the LAES system in the coupling model in the prior art.

[0010] In some illustrative embodiments, the coupling system of LAES and LNG-RG comprises an LAES subsystem, an LNG-RG subsystem, and a coupling cold exchange subsystem. The LAES subsystem comprises a heat storage tank, and a normal-temperature compressor, a multi-stage low-temperature compressor group comprising at least two low-temperature compressors connected in sequence, a low-temperature expander, a liquid-air separator, a liquid air storage tank, a discharging low-temperature pump, and an expander connected in sequence. The normal-temperature compressor, the multi-stage low-temperature compressor group, the low-temperature expander, the liquid-air separator, and the liquid air storage tank form an ambient air liquefaction path for realizing the conversion of ambient air into liquid air. The liquid air storage tank, the discharging low-temperature pump, and the expander form a liquid air regasification path for realizing the conversion of liquid air into regasified air. The coupling cold exchange subsystem supports at least the output of cold energy from the LNG-RG subsystem to the LAES subsystem, and the storage and release of cold energy of the LNG-RG subsystem and the LAES subsystem. The coupling cold exchange subsystem comprises a cryogenic tank for storing and releasing the cryogenic energy generated by the LNG-RG subsystem and the discharging working condition generated by the LAES subsystem. The cold end temperature of the cryogenic tank is a cryogenic temperature, and the hot end temperature is a shallow cold temperature. In the charging working condition of the LAES subsystem, ambient air is compressed by the normal-temperature compressor and outputs the compression heat energy to the heat storage tank for storage, is cooled to a cryogenic temperature by the coupling cold exchange subsystem, is compressed to the shallow cold temperature by the first-stage low-temperature compressor, is cooled to the cryogenic temperature by the coupling cold exchange subsystem, and enters the next-stage low-temperature compressor. The cryogenic temperature is the pressurized outlet temperature in the regasification process of liquefied natural gas, and the shallow cold temperature is the outlet temperature of ambient air after low-temperature compression.

[0011] In some alternative embodiments, the LNG-RG subsystem further comprises a charging cryogenic pump; wherein the ambient air liquefaction path is formed by the ambient air compressor, the multi-stage cryogenic compressor set, the charging cryogenic pump, the cryogenic expander, the liquid air separator and the liquid air tank connected in sequence; wherein in the charging mode of the LAES subsystem, the ambient air is compressed by the multi-stage cryogenic compressor, then cooled to a cryogenic temperature by the coupled cold exchange subsystem to enter a fully liquefied or supercritical state, then compressed to a higher pressure by the charging cryogenic pump, then cooled to a cryogenic temperature by the coupled cold exchange subsystem, and then enters the cryogenic expander.

[0012] In some alternative embodiments, the LNG-RG subsystem comprises a liquefied natural gas regasification path for converting liquefied natural gas into regasified natural gas; the coupled cold exchange subsystem further comprises a cryogenic charging heat exchanger, a cryogenic discharging heat exchanger and a natural gas cryogenic heat exchanger; wherein the natural gas cryogenic heat exchanger is arranged on the liquefied natural gas regasification path of the LNG-RG subsystem; wherein the cryogenic charging heat exchanger is arranged on the ambient air liquefaction path of the LAES subsystem and used for cooling the incoming and outgoing ambient air of each cryogenic compressor to a cryogenic temperature; wherein the cryogenic discharging heat exchanger is arranged on the liquid air regasification path of the LAES subsystem and interposed between the discharging cryogenic pump and the expander; wherein the hot end and the cold end of the cryogenic charging heat exchanger, the cryogenic discharging heat exchanger and the natural gas cryogenic heat exchanger are respectively connected with the hot end and the cold end of the cryogenic tank.

[0013] In some alternative embodiments, the LNG-RG subsystem comprises a liquefied natural gas regasification path for converting liquefied natural gas into regasified natural gas; the coupled cold exchange subsystem further comprises a natural gas cryogenic heat exchanger; the number of the cryogenic tanks is plural; wherein the cryogenic tank is a solid packed bed and has the functions of cold storage and cold exchange; wherein each cryogenic tank is arranged on the ambient air liquefaction path and the liquid air regasification path of the LAES subsystem; in the cryogenic tank, the ambient air liquefaction path and the liquid air regasification path have the same path and opposite air flow direction; wherein the cryogenic tank and the cryogenic compressor are arranged in intervals on the ambient air liquefaction path and used for cooling the incoming and outgoing ambient air of each cryogenic compressor to a cryogenic temperature; wherein the natural gas cryogenic heat exchanger is arranged on the liquefied natural gas regasification path of the LNG-RG subsystem; wherein the hot end and the cold end of the natural gas cryogenic heat exchanger are respectively connected with the hot end and the cold end of each cryogenic tank.

[0014] In some alternative embodiments, the coupling cooling subsystem further comprises: a sub-cooling tank for storing and releasing sub-cooling energy generated by the LNG-RG subsystem and sub-cooling energy generated by the LAES subsystem in discharging mode, having a cold end temperature of the sub-cooling temperature and a hot end temperature of ambient temperature; wherein, in any mode of the LAES subsystem, the coupling cooling subsystem outputs sub-cooling energy to the outside of the coupling system through the sub-cooling tank.

[0015] In some alternative embodiments, the LAES subsystem further comprises: a hyper-cooling tank for storing and releasing hyper-cooling energy generated by the LAES subsystem in discharging mode; wherein, in charging mode of the LAES subsystem, the ambient air discharged by the multi-stage cryogenic compressor group is cooled to a deep-cooling temperature by the coupling cooling subsystem, and then sequentially enters the hot end of the hyper-cooling tank, the cryogenic expander and the liquid air separator; the hyper-cooling return air output by the liquid air separator first enters the cold end of the hyper-cooling tank; wherein, in discharging mode of the LAES subsystem, the regasification air first outputs hyper-cooling energy to the hyper-cooling tank, and then outputs deep-cooling energy and sub-cooling energy to the coupling cooling subsystem.

[0016] wherein, the cold end temperature of the hyper-cooling tank is a hyper-cooling temperature, and the hot end temperature of the hyper-cooling tank is a deep-cooling temperature; the hyper-cooling temperature is the pressurized outlet temperature in the regasification process of liquid air.

[0017] In some alternative embodiments, the coupling system further comprises: a return air compressor and a return air expander; wherein, in charging mode of the LAES subsystem, part of the return air flowing out from the hot end of the hyper-cooling tank is sequentially compressed and heated by the return air compressor, cooled to a deep-cooling temperature by the coupling cooling subsystem, expanded and cooled by the return air expander, and then merged into the hyper-cooling return air output from the liquid air separator.

[0018] In some alternative embodiments, the coupling system further comprises: an external heat source for providing external heat energy; in discharging mode of the LAES subsystem, the regasification air is provided with compressed heat energy and external heat energy by the heat storage tank and the external heat source.

[0019] In some alternative embodiments, the deep-cooling tank of the coupling cooling subsystem is a solid packed bed, and the heat exchange device of the coupling cooling subsystem is a heat exchanger; the solid packed bed and the heat exchanger exchange cold energy through a heat exchange medium; or, the deep-cooling tank and the heat exchange device of the coupling cooling subsystem are integrated into a solid packed bed structure, and the ambient air exchanges cold energy with the cold storage medium in the solid packed bed through the pipe wall of the flow pipeline.

[0020] In some alternative embodiments, the cryogenic tank of the coupling refrigeration subsystem comprises a hot-end adiabatic container and a cold-end adiabatic container, the heat exchange device of the coupling refrigeration subsystem is a heat exchanger, the hot end and the cold end of the heat exchanger are connected to the hot-end adiabatic container and the cold-end adiabatic container respectively, and the adiabatic containers are filled with liquid heat exchange medium, and the storage and exchange of cold energy are achieved between the two adiabatic containers through the liquid heat exchange medium.

[0021] In some alternative embodiments, the coupling system further comprises an air purifier arranged on the ambient air liquefaction path of the LAES subsystem between the ambient temperature compressor and the multi-stage cryogenic compressor group; wherein, in the charging working condition of the LAES subsystem, the ambient air is compressed by the ambient temperature compressor, the compression heat energy is recovered by the regenerative tank, and then the ambient air enters the air purifier, is purified, is cooled to a cryogenic temperature by the coupling refrigeration subsystem, and then enters the multi-stage cryogenic compressor group; wherein, in the discharging working condition of the LAES subsystem, the regasified air output by the expander at least partially flows through the air purifier, and then is discharged to the environment.

[0022] Another object of the present application is to provide a coupling method of LAES and LNG-RG to solve the technical problems in the prior art.

[0023] In some illustrative embodiments, the coupling method of LAES and LNG-RG comprises a process of converting ambient air into liquid air for storage in the charging working condition, which comprises ambient temperature compression of the ambient air, recovery of the compression heat energy generated by the compression, reduction of the temperature of the ambient air after the ambient temperature compression to the ambient temperature, and multi-stage cryogenic compression to obtain ambient air at a target pressure; wherein, the temperature of the ambient air before and after each stage of cryogenic compression is cooled to a cryogenic temperature by using the cryogenic energy in the cryogenic tank; wherein, the cryogenic energy in the cryogenic tank comes from the liquefied natural gas regasification process and the liquid air regasification process; wherein, the cold end temperature of the cryogenic tank is the cryogenic temperature, and the cryogenic temperature is the pressurized outlet temperature in the liquefied natural gas regasification process; and the hot end temperature of the cryogenic tank is the shallow cryogenic temperature, and the shallow cryogenic temperature is the outlet temperature of the ambient air after cryogenic compression.

[0024] In some alternative embodiments, the liquefaction phase change temperature of the ambient air at the target pressure is higher than the cryogenic temperature; the process of cooling the temperature of the ambient air before and after each stage of cryogenic compression to the cryogenic temperature by using the cryogenic energy in the cryogenic tank comprises cooling the ambient air after the last stage of cryogenic compression to the cryogenic temperature to obtain liquid air at the target pressure; and the process of converting ambient air into liquid air for storage in the charging working condition further comprises compression of the liquid air at the target pressure to a higher pressure, and then cryogenic expansion.

[0025] In some alternative embodiments, the process of storing the ambient air as liquid air in the charging mode further comprises: cooling the ambient air to a cryogenic temperature using the cryogenic energy in the cryogenic tank, and cooling the ambient air to a hyper-cryogenic temperature using the hyper-cryogenic energy in the hyper-cryogenic tank; wherein the hyper-cryogenic energy in the hyper-cryogenic tank is from the LNG regasification process and the liquid air regasification process.

[0026] In some alternative embodiments, the coupling method further comprises: a process of warming and expanding the regasified air as liquid air in the discharging mode, comprising: recovering the hyper-cryogenic energy in the regasified air from the liquid air regasification process using the hyper-cryogenic tank; and the process of storing the ambient air as liquid air in the charging mode further comprises: cooling the ambient air at the target pressure from the cryogenic temperature to the hyper-cryogenic temperature; wherein the cold end temperature of the hyper-cryogenic tank is the hyper-cryogenic temperature, and the hot end temperature of the hyper-cryogenic tank is the cryogenic temperature; and the hyper-cryogenic temperature is the pressurized outlet temperature in the liquid air regasification process.

[0027] In some alternative embodiments, the process of storing the ambient air as liquid air in the charging mode further comprises: cryogenically expanding the ambient air at the hyper-cryogenic temperature to produce liquid air and hyper-cryogenic return air; separating and discharging the hyper-cryogenic return air, and recovering the hyper-cryogenic energy in the hyper-cryogenic return air using the hyper-cryogenic tank to convert it into cryogenic temperature return air; compressing at least part of the cryogenic temperature return air, and cooling the compressed and warmed part of the return air to the cryogenic temperature using the cryogenic energy in the cryogenic tank, and then cryogenically expanding the cooled part of the return air, and then re-merging the expanded and cooled part of the return air into the separated and discharged hyper-cryogenic return air.

[0028] In some alternative embodiments, the process of storing the ambient air as liquid air in the charging mode further comprises: before the multi-stage cryogenic process, adsorbing the carbon dioxide and water in the ambient air that has been compressed at room temperature and recovered in thermal energy using an air purifier; and the process of storing the ambient air as liquid air in the charging mode further comprises: introducing at least part of the regasified air after work expansion into the air purifier for desorption treatment of carbon dioxide and water.

[0029] Compared with the prior art, the advantages of the present application include:

[0030] The application establishes a coupling cold exchange subsystem between the LAES subsystem and the LNG-RG subsystem to uniformly manage cold energy, and through a double-temperature compression mode of normal-temperature compression and multi-stage low-temperature compression, high-grade cold energy of the LNG-RG subsystem is utilized to directly reduce the temperature of ambient air before entering a low-temperature compressor to a cryogenic temperature, so that the power consumption of the air compression process of the LAES subsystem can be reduced, and the charging and discharging efficiency of the entire LAES subsystem is improved. BRIEF DESCRIPTION OF DRAWINGS

[0031] Fig. 1 is a structure example one of the coupling system in the embodiment of the application;

[0032] Fig. 2 is a running condition A of the structure example one of the coupling system in the embodiment of the application;

[0033] Fig. 3 is a running condition B of the structure example one of the coupling system in the embodiment of the application;

[0034] Fig. 4 is a running condition C of the structure example one of the coupling system in the embodiment of the application;

[0035] Fig. 5 is a structure example two of the coupling system in the embodiment of the application;

[0036] Fig. 6 is a running condition A of the structure example two of the coupling system in the embodiment of the application;

[0037] Fig. 7 is a running condition B of the structure example two of the coupling system in the embodiment of the application;

[0038] Fig. 8 is a running condition C of the structure example two of the coupling system in the embodiment of the application;

[0039] Fig. 9 is a charging and discharging flowchart of the LAES subsystem in the embodiment of the application.

[0040] BRIEF DESCRIPTION OF DRAWINGS

[0041] HXNG-DC (Heat Exchanger Natural Gas-Deep Cold), HXNG-SC (Heat Exchanger Natural Gas-Shallow Cold); C1 (Compressor 1), C2 (Compressor 2), C3 (Compressor 3), CCP (Charging Cryogenic Pump); HXC-H (Heat Exchanger Charging-Heat), HXD-H (Heat Exchanger Discharging-Heat); HXC-SC (Heat Exchanger Charging-Shallow Cold), HXD-SC (Heat Exchanger Discharging-Shallow Cold); HXC-DC1 (Heat Exchanger Charging-Deep Cold 1), HXC-DC2 (Heat Exchanger Charging-Deep Cold 2), HXC-DC3 (Heat Exchanger Charging-Deep Cold 3), HXC-DC4 (Heat Exchanger Charging-Deep Cold 4), HXD-DC (Heat Exchanger Discharging-Deep Cold); HXC-UC (Heat Exchanger Charging-Ultra Cold), HXD-UC (Heat Exchanger Discharging-Ultra Cold);Cryogenic Expander, Liquid Air Separator, Liquid Air Dewar, Discharge Cryogenic Pump, Heat Dewar, Shallow Cold Dewar, Deep Cold Dewar, Deep Cold Dewar 1, Deep Cold Dewar 2, Deep Cold Dewar 3, Ultra Cold Dewar, Compressor-Ultra Cold Air, Expander-Ultra Cold Air, Air Purification Unit, Valve 1, Valve 2, Valve 3, Valve 4, Valve 5, Valve 6, Valve 7, Valve 8, Valve 9, Valve 10, Valve 11, Valve 12, Valve 13, Valve 14, Valve 15, Valve 16, Valve 17, Valve 18, Valve 19, Valve 20, Valve 21, Valve 22, Valve 23, Valve 24, Valve 25;

[0042] ambient air (Air), first ambient air (Air1), second ambient air (Air2), third ambient air (Air3), fourth ambient air (Air4), fifth ambient air (Air5), sixth ambient air (Air6), seventh ambient air (Air7), eighth ambient air (Air8), ninth ambient air (Air9), tenth ambient air (Air10), eleventh ambient air (Air11) DETAILED DESCRIPTION

[0043] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0044] Unless otherwise defined in the present application, the technical terms or scientific terms used in the present application should be understood as the common meanings thereof by those of ordinary skill in the art to which the present application belongs. Unless explicitly described in the present application, the terms "first", "second" and similar words used in the present application do not indicate any order, number or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar words mean that the elements or objects before the words cover the elements or objects listed after the words and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. In order to keep the following description of the embodiments of the present application clear and concise, the present application omits the detailed description of known functions, known components or common knowledge. In the case of not conflicting with each other, each technical feature in the embodiments of the present application can be combined with each other, and the combined embodiment still falls within the protection scope of the present application.

[0045] The embodiments of the present application disclose a coupling system of liquid air energy storage and liquefied natural gas regasification, specifically, as shown in FIGS. 1-8, the coupling system comprises: a LAES subsystem, a LNG-RG subsystem and a coupling cold exchange subsystem.

[0046] The LAES subsystem is used to convert ambient air into liquid air for storage in a charging mode, and to convert liquid air into regasified air for expansion work in a discharging mode. Specifically, the LAES subsystem includes a heat storage tank HD, and a normal-temperature compressor C1, a multi-stage low-temperature compressor group composed of at least two low-temperature compressors connected in series, a low-temperature expander CE, a liquid-air separator LAS, a liquid air storage tank LAD, a discharging low-temperature pump DCP and an expander E connected in series. Among them, the normal-temperature compressor C1, the multi-stage low-temperature compressor group composed of at least two low-temperature compressors connected in series, the low-temperature expander CE, the liquid-air separator LAS and the liquid air storage tank LAD constitute the ambient air liquefaction path in the charging mode of the LAES subsystem, realizing the conversion of ambient air into liquid air for storage; among them, the liquid air storage tank LAD, the discharging low-temperature pump DCP and the expander E connected in series constitute the liquid air regasification path in the discharging mode of the LAES subsystem, realizing the conversion of liquid air into regasified air for expansion work. Among them, the heat storage tank HD recovers compression heat energy from the ambient air discharged from the normal-temperature compressor C1 in the charging mode, and provides the compression heat energy to the regasified air to warm it up and expand it in the discharging mode.

[0047] The LNG-RG subsystem is used to convert liquefied natural gas (LNG) into natural gas (NG); specifically, it includes a liquefied natural gas low-temperature pump (not shown) and a liquefied natural gas regasification pipeline (LNG to NG path in the figure).

[0048] The coupled cold exchange subsystem includes a cold storage device and a cold exchange device; wherein the cold exchange device is used to build a cold exchange system between the LAES subsystem and the LNG-RG subsystem, at least supporting the LNG-RG subsystem to output cold energy to the LAES subsystem, and storing and releasing the cold energy of the LNG-RG subsystem and the LAES subsystem, for example, supporting the LNG-RG subsystem to output cold energy to the LAES subsystem, the LNG-RG subsystem to output cold energy to the cold storage device, and the cold storage device to output cold energy to the LAES subsystem; the cold storage device is used to store and release the cold energy of the two subsystems. Among them, in some embodiments, the cold storage device can have the functions of cold storage and cold exchange at the same time, and can at least replace part of the cold exchange device.

[0049] In the charging mode of the LAES subsystem, the ambient air is compressed by the normal-temperature compressor in sequence and outputs the compression heat energy to the storage tank, and then is cooled to the cryogenic temperature by the deep cooling energy generated by the LNG-RG subsystem and the stored cold energy in the discharging mode of the LAES subsystem, and is compressed to the shallow cooling temperature by the first-stage low-temperature compressor, and is cooled to the cryogenic temperature by the coupled cooling subsystem to enter the next-stage low-temperature compressor for compression, until the ambient air is compressed by the last-stage low-temperature compressor to obtain the target pressure, and is cooled to the cryogenic temperature by the coupled cooling subsystem, and is expanded by the low-temperature expander, and the converted liquid air is stored in the liquid air storage tank in the liquid air separator.

[0050] In the charging mode of the LAES subsystem, the ambient air is compressed by the normal-temperature compressor in sequence and outputs the compression heat energy to the storage tank, and then is cooled to the cryogenic temperature by the deep cooling energy generated by the LNG-RG subsystem and the stored cold energy in the discharging mode of the LAES subsystem, and is compressed to the shallow cooling temperature by the first-stage low-temperature compressor, and is cooled to the cryogenic temperature by the coupled cooling subsystem to enter the next-stage low-temperature compressor for compression, until the ambient air is compressed by the last-stage low-temperature compressor to obtain the target pressure, and is cooled to the cryogenic temperature by the coupled cooling subsystem, and is expanded by the low-temperature expander, and the converted liquid air is stored in the liquid air storage tank in the liquid air separator.

[0051] Specifically, the pressurized outlet temperature in the LNG regasification process refers to the temperature at the outlet position of the LNG cryogenic pump in the LNG regasification process; and the outlet temperature of the ambient air after low-temperature compression refers to the temperature at the outlet position of each low-temperature compressor in the ambient air liquefaction process.

[0052] Further, the cold storage device comprises a deep tank DCD connected to the cooling system of the coupled cooling subsystem, and is used to store and release the deep cooling energy generated by the LNG-RG subsystem. In some embodiments, the deep tank can also be used to store and release the deep cooling energy generated in the discharging mode of the LAES subsystem, so that the coupled cooling subsystem can use the deep cooling energy of the LNG-RG subsystem and the stored deep cooling energy in the discharging mode of the LAES subsystem to cool the ambient air to the cryogenic temperature; wherein, in the case that the deep tank participates in the cooling of the charging mode of the LAES subsystem or the LNG-RG subsystem outputs cold energy to the deep tank, the cold end temperature is the cryogenic temperature, i.e. the temperature of the LNG after being pressurized by the LNG discharge cryogenic pump and before being heated by any heat source, which is the lowest temperature of the cold energy that the LNG-RG can output; and the hot end temperature is the shallow cooling temperature, i.e. the outlet temperature of the ambient air after low-temperature compression.

[0053] Generally, the pressurized outlet temperature in the liquefied natural gas regasification process only exists on the LNG-RG subsystem side, and the temperature after the cold exchange to the coupling cold exchange subsystem side (such as a cold storage device such as a cryogenic tank) and the liquid air energy storage system side is affected by the heat exchange efficiency, the pinch point of the heat exchanger, and the like, and cannot continue to maintain the pressurized outlet temperature in the liquefied natural gas regasification process, which is known in the art. In order to facilitate understanding, the cryogenic temperature reaching the coupling cold exchange subsystem side (such as a cold storage device such as a cryogenic tank) and the liquid air energy storage system side is set as the pressurized outlet temperature in the liquefied natural gas regasification process in the embodiments of the present application; however, it should be noted that in actual application, the cryogenic temperature is slightly different from the pressurized outlet temperature in the liquefied natural gas regasification process, and the difference between the actual cryogenic temperature and the pressurized outlet temperature in the liquefied natural gas regasification process depends on the specific implementation parameters, but such a difference does not affect the coverage and protection content of the present application.

[0054] The present application establishes a coupling cold exchange subsystem between the LAES subsystem and the LNG-RG subsystem, and through the dual-temperature compression mode of normal-temperature compression and multi-stage low-temperature compression, the high-grade cold energy of the LNG-RG subsystem is used to directly reduce the temperature of the ambient air before entering the low-temperature compressor to a cryogenic temperature, thereby reducing the power consumption of the air compression process of the LAES subsystem and further improving the charging and discharging efficiency of the entire LAES subsystem.

[0055] The multi-stage low-temperature compressor set in the embodiments of the present application is composed of at least two low-temperature compressors connected in series, such as a two-stage low-temperature compressor set, a three-stage low-temperature compressor set, a four-stage low-temperature compressor set, and the like. Among them, the multi-stage low-temperature compressor set is mainly used to gradually compress the ambient air to the target pressure, thereby completing the collection of the target volume of ambient air, and therefore the number of stages of the multi-stage low-temperature compressor set can be set according to the system design requirements.

[0056] It should be noted that as the pressure of the ambient air gradually increases after being compressed, and the present application cools it to a cryogenic temperature, the dew point of the ambient air at this time may have been higher than the cryogenic temperature, thereby potentially causing equipment damage risk to the next stage of low-temperature compressor, and therefore the temperature of the ambient air before entering each stage of low-temperature compressor should not be lower than the dew point temperature of the ambient air.

[0057] For general system design, the case that the dew point of the ambient air is higher than the cryogenic temperature often occurs after the second-to-last stage of low-temperature compression or in the process of the last stage of low-temperature compression, and therefore the temperature of the ambient air before entering the last stage of low-temperature compressor should not be lower than the dew point temperature of the ambient air. Preferably, the ambient air entering the last stage of low-temperature compressor is at least 5 degrees above the dew point temperature.

[0058] On the other hand, it is possible that the high-pressure ambient air cooled to a cryogenic temperature has been completely liquefied in the multi-stage cryogenic compression process, at which point the cryogenic compressor cannot complete the subsequent compression, and thus the subsequent compression can be completed by the cryogenic pump, so as to collect the target volume of high-pressure liquid air.

[0059] Further, the LAES subsystem can further comprise a charging cryogenic pump for further compressing the air in the liquid or supercritical state at the cryogenic temperature to a higher pressure;

[0060] The ambient air liquefaction path comprises, in sequence, the ambient temperature compressor, the multi-stage cryogenic compressor group, the charging cryogenic pump, the cryogenic expander, the liquid air separator, and the liquid air tank.

[0061] In the charging mode of the LAES subsystem, the ambient air is compressed by the multi-stage cryogenic compressor, cooled to a cryogenic temperature by the coupled cold exchange subsystem, enters a completely liquefied or supercritical state, is compressed to a higher pressure required by design by the charging cryogenic pump, is cooled to a cryogenic temperature by the coupled cold exchange subsystem, and then enters the cryogenic expander.

[0062] In some embodiments, the cold storage device of the coupled cold exchange subsystem in the present application can further comprise a shallow cooling tank SCD for at least storing and releasing the shallow cooling energy generated by the LNG-RG subsystem. The cold end temperature of the shallow cooling tank is the hot end temperature of the deep cooling tank, and the hot end temperature of the shallow cooling tank is the ambient temperature.

[0063] In some embodiments, the temperature boundaries of the hot end and the cold end of the deep cooling tank and the shallow cooling tank in the present application will have some differences according to the actual operating conditions and the actual design parameters. For example, the shallow cooling temperature defined in the present application is the temperature of the ambient air discharged by the cryogenic compressor. The temperatures of the ambient air discharged by different stages of cryogenic compressors will have slight differences, which depend on the actual operating conditions and the compression ratio settings of the cryogenic compressors. The setting of the hot end temperature of the deep cooling tank in the present application is to maximize the matching of the temperatures of the ambient air before and after the cryogenic compressor, so as to improve the heat exchange efficiency. The existence of such differences is within the common knowledge in the art, and does not affect the scope or content of protection of the present application.

[0064] At this time, the deep cooling tank DCD and the shallow cooling tank SCD in the coupled cold exchange subsystem can recover and release the deep cooling energy and the shallow cooling energy generated by the LNG-RG subsystem (and / or the LAES subsystem) in sequence.

[0065] In some embodiments, the shallow cooling tank SCD in the embodiment of the present application can also cooperate with the deep cooling tank DCD to recover the shallow cooling energy generated from the liquefied air gasification in the discharging condition of the LAES subsystem, and the deep cooling energy and the shallow cooling energy generated from the liquefied air gasification are recovered and released in sequence by the deep cooling tank DCD and the shallow cooling tank SCD.

[0066] Further, the coupling cooling subsystem in the embodiment of the present application can use the shallow cooling energy generated by the LNG-RG subsystem and / or the shallow cooling energy in the shallow cooling tank to precool the ambient air for which the compression heat energy is recovered in the charging condition of the LAES subsystem, and the ambient air is cooled to the shallow cooling temperature, and then the ambient air is further cooled to the deep cooling temperature, so that the consumption of the deep cooling energy can be reduced, the cold energy resources can be reasonably utilized, and the consumption of the high-quality cold energy can be reduced.

[0067] Further, the shallow cooling energy recovered from the liquefied air gasification in the discharging condition of the LAES subsystem is sufficient to precool the ambient air to the shallow cooling temperature in the charging condition of the LAES subsystem, so that the process basically does not consume the shallow cooling energy from the LNG-RG subsystem, and thus the shallow cooling energy in the shallow cooling tank can be output to the outside of the coupling system in any condition of the LAES subsystem by the coupling cooling subsystem, so that economic benefits can be generated. In addition, the shallow cooling energy of the two subsystems is recovered by the shallow cooling tank at the same time, so that the equipment cost is also reduced.

[0068] In some embodiments, the LAES subsystem in the embodiment of the present application further comprises: an ultra-cooling tank UCD for storing and releasing the ultra-cooling energy generated in the discharging condition of the LAES subsystem; the ultra-cooling tank UCD recovers the ultra-cooling energy from the liquefied air gasification in the discharging condition, and provides the ultra-cooling energy to the ambient air which is cooled to the deep cooling temperature after the multi-stage low-temperature compression in the charging condition, so that the temperature of the ambient air in this stage is cooled to the ultra-cooling temperature, and the ambient air at the ultra-cooling temperature is used for low-temperature expansion, so as to improve the liquefaction efficiency of the ambient air.

[0069] The pressurized outlet temperature in the liquefied air gasification process refers to the outlet temperature of the point low-temperature pump in the liquefied air gasification process.

[0070] Since the ultra-cooling temperature of the ultra-cooling energy is lower than the pressurized outlet temperature in the liquefied natural gas gasification process, the ultra-cooling energy cannot be provided by the LNG-RG subsystem, and thus the ultra-cooling energy has the highest value of cold energy in the coupling system, and the recovery and release by the ultra-cooling tank UCD can effectively improve the liquefaction efficiency of the ambient air.

[0071] Specifically, in the charging mode of the LAES subsystem, the ambient air, after being compressed at low temperature by the last stage of the multi-stage low temperature compressor and cooled to a deep cooling temperature by the coupled cold exchange subsystem, enters the hot end of the ultra cold tank UCD, and then flows out from the cold end of the ultra cold tank UCD, sequentially enters the low temperature expander CE and the liquid air separator LAS, and is stored into the liquid air storage tank LAD by the liquid air separator LAS. The ultra cold return air output from the liquid air separator LAS first enters the cold end of the ultra cold tank UCD, and then flows out from the hot end of the ultra cold tank UCD, thereby completing the recovery of the ultra cold energy in the ultra cold return air.

[0072] In some embodiments, the LAES subsystem in the embodiments of the present application can further include a return air compressor C-UCA and a return air expander E-UCA; wherein, in the charging mode of the LAES subsystem, at least part of the return air flowing out from the hot end of the ultra cold tank UCD is sequentially compressed and heated by the return air compressor C-UCA, cooled to a deep cooling temperature by the coupled cold exchange subsystem, expanded and cooled by the return air expander E-UCA, and then merged into the ultra cold return air output from the liquid air separator LAS and entering the cold end of the ultra cold tank UCD, thereby supplementing the ultra cold energy.

[0073] In some embodiments, the LAES subsystem in the embodiments of the present application can further include an air purifier APU arranged between the normal temperature compressor C1 and the multi-stage low temperature compressor group, for removing carbon dioxide and water in the ambient air entering the LAES subsystem, so that the ambient air without carbon dioxide and water is subjected to subsequent low temperature compression. Specifically, in the charging mode of the LAES subsystem, the ambient air, after being compressed by the normal temperature compressor C1 and outputting the compression heat energy to the heat storage tank HD, enters the air purifier APU, is cooled to a deep cooling temperature by the coupled cold exchange subsystem after being purified, and then enters the low temperature compressor group.

[0074] The principle of the air purifier removing carbon dioxide and water in the ambient air is to adsorb the carbon dioxide and water in the ambient air by the molecular sieve, so that at least part of the regasified air output by the expander can flow through the air purifier and be discharged to the environment, and the desorption of carbon dioxide and water in the air purifier is completed by using this part of the ambient air, so that the air purifier can be cyclically operated in the charging and discharging process.

[0075] In some embodiments, the coupled system in the embodiments of the present application can further include an external heat source for providing external heat energy; wherein, the external heat source is not limited to ambient air, seawater and other environmental heat sources, solar energy, or industrial waste heat.

[0076] In the discharging mode of the liquid air subsystem, the heat storage tank HD and the external heat source can jointly provide the compression heat energy and the external heat energy to the regasified air to heat and expand the regasified air.

[0077] Optionally, the expander E in the embodiment of the present application can be a multi-stage expander group composed of multiple expander devices connected in series, and the regasified air entering each expander can be warmed and expanded by using compression heat energy and external heat energy, respectively. For example, the regasified air can absorb external heat energy provided by an external heat source before entering a preceding expander, and can absorb compression heat energy provided by a heat storage tank before entering a second expander; or the regasified air can absorb compression heat energy provided by a heat storage tank before entering a first expander, and can absorb external heat energy provided by an external heat source before entering a subsequent expander.

[0078] In some embodiments, the cold storage medium of the cold storage device of the coupled cold exchange subsystem in the embodiment of the present application can be a solid medium or a liquid medium, and the heat exchange device can be a heat exchanger. The heat exchanger is used to build a cold exchange system of the coupled cold exchange subsystem, so as to realize cold energy exchange among the cold storage device, the LAES subsystem and the LNG-RG subsystem. The number and implementation position of the heat exchanger can be determined according to system design requirements, and the selected heat exchange medium can be selected according to different temperature requirements, which is not limited in the present application.

[0079] In one embodiment, the cold storage device of the coupled cold exchange subsystem in the embodiment of the present application is a solid packed bed, and the heat exchange device is a heat exchanger. The heat exchanger builds a cold exchange system of the LAES subsystem, the LNG-RG subsystem and the solid packed bed, and cold energy exchange is realized among them through a heat exchange medium.

[0080] In another embodiment, the cold storage device of the coupled cold exchange subsystem in the embodiment of the present application is a solid packed bed, and is integrated with a part of the heat exchange device function. The solid packed bed is simultaneously connected to an ambient air liquefaction path in a charging condition of the LAES subsystem and an ambient air regasification path in a discharging condition of the LAES subsystem. At this time, the cold storage medium in the solid packed bed can directly exchange cold energy with the ambient air in the charging and discharging conditions of the LAES subsystem through a pipe wall. Another part of the heat exchange device is a heat exchanger, which can realize cold energy exchange between the LNG-RG subsystem and the solid packed bed, and further realize cold energy exchange among the three.

[0081] In another embodiment, the cold storage device (e.g., a cryogenic tank) of the coupled cold exchange subsystem in the embodiment of the present application comprises two independent adiabatic containers, which are respectively used as the hot end and the cold end of the cold storage device; the heat exchange device is a heat exchanger, the hot end of the heat exchanger is connected with the hot end of the cold storage device, and the cold end of the heat exchanger is connected with the cold end of the cold storage device, thereby forming a cold exchange system. The adiabatic containers are filled with liquid heat exchange medium (e.g., liquid propane) to realize the storage and exchange of cold energy, and the heat exchanger is also selected from the same liquid heat exchange medium. When the cold storage device stores cold energy, the heat exchange medium flows from the hot end of the cold storage device (the first adiabatic container) to the cold end of the cold storage device (the second adiabatic container) through the heat exchanger, and absorbs cold energy from the heat exchanger in the process of transfer; and when the cold storage device releases cold energy, the heat exchange medium flows from the cold end of the cold storage device (the second heat exchange container) to the hot end of the cold storage device (the first heat exchange container) through the heat exchanger, and outputs cold energy through the heat exchanger in the process of transfer.

[0082] In order to facilitate those skilled in the art to quickly understand different collocation structures of the coupled cold exchange subsystem, the present application discloses two preferred embodiments of the coupled system with different structures for different structures of the coupled cold exchange subsystem; it should be understood that the specific coupled system disclosed in the embodiment of the present application is only used for quickly understanding different construction structures, and should not limit the actual protection scope of the present application.

[0083] As shown in FIG. 1, the embodiment of the present application discloses a coupled system of liquid air energy storage and liquefied natural gas regasification, which comprises a LAES subsystem, a LNG-RG subsystem and a coupled cold exchange subsystem.

[0084] The LAES subsystem comprises: a heat storage tank HD, an ultra-cold tank UCD, and a normal-temperature compressor C1, a heat storage charging heat exchanger HXC-H, an air purifier APU, a two-stage low-temperature compressor set composed of two low-temperature compressors (C2, C3) connected in series, a charging low-temperature pump CCP, an ultra-cold charging heat exchanger HXC-UC, a low-temperature expander CE, a liquid air separator LAS, a liquid air storage tank LAD, a discharging low-temperature pump DCP, an ultra-cold discharging heat exchanger HXD-UC, a heat storage discharging heat exchanger HXD-H, and an expander set (a first expander E1, a second expander E2, a third expander E3, a fourth expander E4), and a return air compressor C-UCA and a return air expander E-UCA. The hot ends of the heat storage tank HD, the heat storage charging heat exchanger HXC-H, and the heat storage discharging heat exchanger HXD-H are connected by a first valve V1, and the cold ends are connected by a second valve V2; the specific heat exchange circuit can be controlled by the first valve V1 and the second valve V2; the hot ends of the ultra-cold tank UCD, the ultra-cold charging heat exchanger HXC-UC, and the ultra-cold discharging heat exchanger HXD-UC are connected by a third valve V3, and the cold ends are connected by a fourth valve V4; the specific cooling circuit can be controlled by the third valve V3 and the fourth valve V4. The liquid air storage tank LAD is connected between the liquid air separator LAS and the discharging low-temperature pump DCP through a tenth valve V10. The first environment heat exchanger HXD2 is arranged between the first expander E1 and the second expander E2, the second environment heat exchanger HXD3 is arranged between the second expander E2 and the third expander E3, the third environment heat exchanger HXD4 is arranged between the third expander E3 and the fourth expander E4, and the first environment heat exchanger HXD2, the second environment heat exchanger HXD2, and the third environment heat exchanger HXD2 obtain environment heat energy from an environment heat source.

[0085] The LNG-RG subsystem comprises: a liquefied natural gas low-temperature pump and a liquefied natural gas regasification pipeline.

[0086] The coupling cold exchange subsystem comprises: a shallow cold tank SCD, a deep cold tank DCD, a shallow cold charging heat exchanger HXC-SC, a shallow cold discharging heat exchanger HXD-SC, a first deep cold charging heat exchanger HXC-DC1, a second deep cold charging heat exchanger HXC-DC2, a third deep cold charging heat exchanger HXC-DC3, a fourth deep cold charging heat exchanger HXC-DC4, a deep cold discharging heat exchanger HXD-DC, a natural gas deep cold heat exchanger HXNG-DC, and a natural gas shallow cold heat exchanger HXNG-SC.

[0087] The shallow cooling charging heat exchanger HXC-SC, the shallow cooling discharging heat exchanger HXD-SC, the first deep cooling charging heat exchanger HXC-DC1, the second deep cooling charging heat exchanger HXC-DC2, the third deep cooling charging heat exchanger HXC-DC3, the fourth deep cooling charging heat exchanger HXC-DC4 and the deep cooling discharging heat exchanger in the coupling refrigeration subsystem are coupled in the LAES subsystem, so that the charging path of the LAES subsystem sequentially comprises: the normal temperature compressor C1, the heat storage charging heat exchanger HXC-H, the air purifier APU, the shallow cooling charging heat exchanger HXC-SC, the first deep cooling charging heat exchanger HXC-DC1, the first stage low temperature compressor C2, the second deep cooling charging heat exchanger HXC-DC2, the second stage low temperature compressor C3, the third deep cooling charging heat exchanger HXC-DC3, the charging low temperature pump CCP, the fourth deep cooling charging heat exchanger HXC-DC4, the super cooling charging heat exchanger HXC-UC, the liquid air separator LAS and the liquid air storage tank LAD; and the discharging path of the LAES subsystem sequentially comprises: the liquid air storage tank LAD, the discharging low temperature pump DCP, the super cooling discharging heat exchanger HXD-UC, the deep cooling discharging heat exchanger HXD-DC, the shallow cooling discharging heat exchanger HXD-SC, the heat storage discharging heat exchanger HXD-H, the first expander E1, the second ambient heat exchanger HXD2, the second expander E2, the third ambient heat exchanger HXD3, the third expander E3, the fourth ambient heat exchanger HXD4 and the fourth expander E4.

[0088] The natural gas deep cooling heat exchanger HXNG-DC and the natural gas shallow cooling heat exchanger HXNG-SC in the coupling refrigeration subsystem are coupled in the LNG-RG subsystem, so that the natural gas deep cooling heat exchanger HXNG-DC and the natural gas shallow cooling heat exchanger HXNG-SC are arranged in sequence along the liquefied natural gas regasification direction on the liquefied natural gas regasification pipeline.

[0089] The hot ends of the shallow cooling tank SCD, the shallow cooling charging heat exchanger HXC-SC, the shallow cooling discharging heat exchanger HXD-SC and the natural gas shallow cooling heat exchanger HXNG-SC are connected through the fifth valve V5 respectively, and the cold ends are connected through the sixth valve V6 respectively; the specific refrigeration circuit can be controlled by the fifth valve V5 and the sixth valve V6. The hot ends of the deep cooling tank DCD, the first deep cooling charging heat exchanger HXC-DC1, the second deep cooling charging heat exchanger HXC-DC2, the third deep cooling charging heat exchanger HXC-DC3, the fourth deep cooling charging heat exchanger HXC-DC4, the deep cooling discharging heat exchanger HXD-DC and the natural gas deep cooling heat exchanger HXNG-DC are connected through the seventh valve V7 respectively, and the cold ends are connected through the eighth valve V8 respectively; the specific refrigeration circuit can be controlled by the seventh valve V7 and the eighth valve V8.

[0090] The super-cooled return air from the gas phase outlet of the liquid air separator LAS in the LAES subsystem enters the super-cooled charge heat exchanger HXC-UC, the first deep-cooled charge heat exchanger HXC-DC1 and the shallow-cooled charge heat exchanger HXC-SC in sequence, and then returns to the inlet of the normal-temperature compressor C1. The ninth valve V9 is arranged on the pipeline of the super-cooled return air between the liquid air separator LAS and the super-cooled charge heat exchanger HXC-UC, and a part of the super-cooled return air is led out by the ninth valve V9, enters the return air compressor C-UCA, the first deep-cooled charge heat exchanger HXC-DC1 and the return air expander E-UCA in sequence, and then returns to the inlet of the super-cooled return air of the super-cooled charge heat exchanger HXC-UC.

[0091] As shown in FIG. 2, under the charging working condition of the LAES subsystem, the LNG-RG subsystem operates, a heat exchange loop is formed between the heat storage tank HD and the heat storage charge heat exchanger HXC-H, a cold exchange loop is formed between the shallow-cooled tank SCD, the natural gas shallow-cooled heat exchanger HXNG-SC and the shallow-cooled charge heat exchanger HXC-SC, a cold exchange loop is formed between the deep-cooled tank DCD, the natural gas deep-cooled heat exchanger HXNG-DC, the first deep-cooled charge heat exchanger HXC-DC1, the second deep-cooled charge heat exchanger HXC-DC2, the third deep-cooled charge heat exchanger HXC-DC3 and the fourth deep-cooled charge heat exchanger HXC-DC4, and a cold exchange loop is formed between the super-cooled tank UCD and the super-cooled charge heat exchanger HXC-UC.

[0092] At this time, the ambient air AIR enters the normal-temperature compressor C1, the heat storage charge heat exchanger HXC-H, the air purifier APU, the shallow-cooled charge heat exchanger HXC-SC, the first deep-cooled charge heat exchanger HXC-DC1, the first-stage low-temperature compressor C2, the second deep-cooled charge heat exchanger HXC-DC2, the second-stage low-temperature compressor C3, the third deep-cooled charge heat exchanger HXC-DC3, the charge low-temperature pump CCP, the fourth deep-cooled charge heat exchanger HXC-DC4, the super-cooled charge heat exchanger HXC-UC, the low-temperature expander CE, the liquid air separator LAS and the liquid air storage tank LAD in sequence, and the super-cooled return air discharged from the liquid air separator LAS enters the super-cooled charge heat exchanger HXC-UC, the first deep-cooled charge heat exchanger HXC-DC1, the shallow-cooled charge heat exchanger HXC-SC and then returns to the inlet of the normal-temperature compressor C1; wherein a part of the return air discharged from the super-cooled charge heat exchanger HXC-UC enters the return air compressor C-UCA, the first deep-cooled charge heat exchanger HXC-DC1, the return air expander E-UCA and then returns to the inlet of the super-cooled return air of the super-cooled charge heat exchanger HXC-UC.

[0093] As shown in FIG. 3, in the static state of the LAES subsystem, the LNG-RG subsystem operates, and a cold exchange loop is formed between the shallow cooling tank SCD and the natural gas shallow cooling heat exchanger HXNG-SC, and a cold exchange loop is formed between the deep cooling tank DCD and the natural gas deep cooling heat exchanger HXNG-DC.

[0094] At this time, the deep cooling energy and the shallow cooling energy of the LNG-RG subsystem are output to the deep cooling tank DCD and the shallow cooling tank SCD, respectively.

[0095] As shown in FIG. 4, in the discharging state of the LAES subsystem, the LNG-RG subsystem operates, and a heat exchange loop is formed between the heat storage tank HD and the heat storage discharging heat exchanger HXD-H, a cold exchange loop is formed between the shallow cooling tank SCD, the natural gas shallow cooling heat exchanger HXNG-SC and the shallow cooling discharging heat exchanger HXD-SC, a cold exchange loop is formed between the deep cooling tank DCD, the natural gas deep cooling heat exchanger HXNG-DC and the deep cooling discharging heat exchanger HXD-DC, and a cold exchange loop is formed between the ultra-cooling tank UCD and the ultra-cooling discharging heat exchanger HXD-UC.

[0096] At this time, the liquid air in the liquid air storage tank LAD is pressurized by the discharging cryogenic pump DCP, and then sequentially enters the ultra-cooling discharging heat exchanger HXD-UC, the deep cooling discharging heat exchanger HXD-DC, the shallow cooling discharging heat exchanger HXD-SC, the heat storage discharging heat exchanger HXD-H, the first expander E1, the second ambient heat exchanger HXD2, the second expander E2, the third ambient heat exchanger HXD3, the third expander E3, the fourth ambient heat exchanger HXD4 and the fourth expander E4.

[0097] As shown in FIG. 5, the coupling system for liquid air energy storage and liquefied natural gas regasification disclosed in the embodiment of the present application comprises: a LAES subsystem, a LNG-RG subsystem and a coupling cold exchange subsystem; wherein the heat exchange equipment of the LAES subsystem has both heat storage and heat exchange functions, and the cold storage equipment in the LAES subsystem and the coupling cold exchange subsystem has both cold storage and cold exchange functions, and specifically:

[0098] The LAES subsystem comprises: a normal-temperature compressor C1, a heat storage tank HD, an air purifier APU, a first-stage low-temperature compressor C2, a second-stage low-temperature compressor C3, an ultra-cooling tank UCD, a low-temperature expander CE, a liquid air separator LAS, a liquid air storage tank LAD, a discharging cryogenic pump DCP and an expander E.

[0099] The LNG-RG subsystem comprises: a liquefied natural gas regasification pipeline.

[0100] The coupling cold exchange subsystem comprises: a shallow cooling tank SCD, a first deep cooling tank DCD1, a second deep cooling tank DCD2, a third deep cooling tank DCD3, a natural gas deep cooling heat exchanger HXNG-DC and a natural gas shallow cooling heat exchanger HXNG-SC.

[0101] The shallow cooling tank SCD, the first deep cooling tank DCD1, the second deep cooling tank DCD2, and the third deep cooling tank DCD3 in the cooling exchange subsystem are coupled in the LAES subsystem, so that the charging path of the LAES subsystem comprises, in sequence: the normal-temperature compressor C1, the eleventh valve V11, the heat storage tank HD, the twelfth valve V12, the air purifier APU, the thirteenth valve V13, the shallow cooling tank SCD, the first deep cooling tank DCD1, the fourteenth valve V14, the first-stage low-temperature compressor C2, the fifteenth valve V15, the second deep cooling tank DCD2, the sixteenth valve V16, the second-stage low-temperature compressor C3, the seventeenth valve V17, the third deep cooling tank DCD3, the ultra-cooling tank UCD, the eighteenth valve V18, the low-temperature expander CE, the liquid air separator LAS, the nineteenth valve V19, and the liquid air storage tank LAD; and the discharging path of the LAES subsystem comprises, in sequence: the liquid air storage tank LAD, the nineteenth valve V19, the discharging low-temperature pump DCP, the eighteenth valve V18, the ultra-cooling tank UCD, the third deep cooling tank DCD3, the seventeenth valve V17, the sixteenth valve V16, the second deep cooling tank DCD2, the fifteenth valve V15, the fourteenth valve V14, the first deep cooling tank DCD1, the shallow cooling tank SCD, the thirteenth valve V13, the twelfth valve V12, the heat storage tank HD, the eleventh valve V11, and the expander E. Part of the charging path and the discharging path of the LAES subsystem are multiplexed, but the air flow directions are opposite.

[0102] The natural gas deep cooling heat exchanger HXNG-DC and the natural gas shallow cooling heat exchanger HXNG-SC in the cooling exchange subsystem are coupled in the LNG-RG subsystem, so that the natural gas deep cooling heat exchanger HXNG-DC and the natural gas shallow cooling heat exchanger HXNG-SC are arranged in sequence along the liquefied natural gas regasification direction on the liquefied natural gas regasification pipeline.

[0103] The heat end of the shallow cooling tank SCD is connected to the heat end of the natural gas shallow cooling heat exchanger HXNG-SC, and the cold end of the shallow cooling tank SCD is connected to the cold end of the natural gas shallow cooling heat exchanger HXNG-SC; the heat end of the first deep cooling tank DCD1, the second deep cooling tank DCD2, and the third deep cooling tank DCD3 is connected to the heat end of the natural gas deep cooling heat exchanger HXNG-DC through the twenty-second valve V22 and the twenty-third valve V23, and the cold end of the first deep cooling tank DCD1, the second deep cooling tank DCD2, and the third deep cooling tank DCD3 is connected to the cold end of the natural gas deep cooling heat exchanger HXNG-DC through the twenty-fourth valve V24 and the twenty-fifth valve V25; and the specific cooling circuit can be controlled by the twenty-second valve V22, the twenty-third valve V23, the twenty-fourth valve V24, and the twenty-fifth valve V25.

[0104] The super-cooled return air from the gas phase outlet of the liquid air separator in the LAES subsystem enters the twentieth valve V20, the super-cooled tank UCD, the twenty-first valve V21, the natural gas deep cooling heat exchanger HXNG-DC, the natural gas shallow cooling heat exchanger HXNG-SC in turn, and then returns to the inlet of the normal temperature compressor C1. A pipeline of the super-cooled return air flowing out of the super-cooled tank LAD is connected to the twenty-first valve V21, and a part of the super-cooled return air is introduced into the return air compressor C-UCA, the natural gas deep cooling heat exchanger HXNG-DC, the return air expander E-UCA in turn, and then returns to the inlet of the super-cooled tank UCD.

[0105] As shown in FIG. 6, in the charging working condition of the LAES subsystem, the LNG-RG subsystem operates, and a cooling exchange loop is formed between the shallow cooling tank SCD and the natural gas shallow cooling heat exchanger HXNG-SC, and a cooling exchange loop is formed between the first deep cooling tank DCD1, the second deep cooling tank DCD2, the third deep cooling tank DCD3 and the natural gas deep cooling heat exchanger HXNG-DC.

[0106] At this time, the ambient air AIR enters the normal temperature compressor C1, the heat accumulator HD, the air purifier APU, the shallow cooling tank SCD, the first deep cooling tank DCD1, the first stage low temperature compressor C2, the second deep cooling tank DCD2, the second stage low temperature compressor C3, the third deep cooling tank DCD3, the super-cooled tank UCD, the low temperature expander CE, the liquid air separator LAS and the liquid air storage tank LAD in turn, and the super-cooled return air discharged from the liquid air separator LAS enters the super-cooled tank UCD, the natural gas deep cooling heat exchanger HXNG-DC, the natural gas shallow cooling heat exchanger HXNG-SC in turn, and then returns to the inlet of the normal temperature compressor C1; wherein a part of the super-cooled return air discharged from the super-cooled tank UCD enters the return air compressor C-UCA, the natural gas deep cooling heat exchanger HXNG-DC, the return air expander E-UCA in turn, and then returns to the inlet of the super-cooled tank UCD.

[0107] As shown in FIG. 7, in the static working condition of the LAES subsystem, the LNG-RG subsystem operates, and a cooling exchange loop is formed between the shallow cooling tank SCD and the natural gas shallow cooling heat exchanger HXNG-SC, and a cooling exchange loop is formed between the first deep cooling tank DCD1, the second deep cooling tank DCD2, the third deep cooling tank DCD3 and the natural gas deep cooling heat exchanger HXNG-DC.

[0108] At this time, the deep cooling energy and the shallow cooling energy of the LNG-RG subsystem are output to the first deep cooling tank DCD1, the second deep cooling tank DCD2, the third deep cooling tank DCD3 and the shallow cooling tank SCD respectively.

[0109] As shown in Figure 8, in the discharging working condition of the LAES subsystem, the LNG-RG subsystem operates, a cold exchange loop is formed between the shallow cooling tank SCD and the natural gas shallow cooling heat exchanger HXNG-SC, and a cold exchange loop is formed between the first deep cooling tank DCD1, the second deep cooling tank DCD2, the third deep cooling tank DCD3 and the natural gas deep cooling heat exchanger HXNG-DC.

[0110] At this time, the liquid air in the liquid air storage tank is pressurized by the discharging cryogenic pump DCP, and then sequentially enters the super-cooling tank, the third deep cooling tank DCD3, the second deep cooling tank DCD2, the first deep cooling tank DCD1, the shallow cooling tank SCD, the heat storage tank HD and the expander E.

[0111] The LAES subsystem in the coupling system in the embodiment of the application can operate independently in cooperation with the coupling cold exchange subsystem, and the LNG-RG subsystem can also operate independently, while the LAES subsystem can operate in coupling with the LNG-RG subsystem in the charging working condition, the static working condition and the discharging working condition. Specifically, in the charging working condition of the LAES subsystem and the LNG-RG subsystem operating, the cold energy generated by the LNG-RG subsystem is output to the LAES subsystem through the coupling cold exchange subsystem; in the static working condition or the discharging working condition of the LAES subsystem and the LNG-RG subsystem operating, the coupling cold exchange subsystem directly stores the cold energy generated by the LNG-RG subsystem. When the LNG-RG subsystem is stopped, the LAES subsystem can operate independently in cooperation with the coupling cold exchange subsystem, and when the LAES system is stopped, the LNG-RG subsystem can operate independently in cooperation with the coupling cold exchange subsystem.

[0112] In order to more clearly illustrate the implementation method and advantages of the application, the thermodynamic model of the embodiment is simulated by using the Aspen HYSYS software for the embodiment described with reference to Figure 1 of the application. The simulation results are shown in Table 1 as follows:

[0113] Table 1: Key modeling assumptions and simulation results of the LAES subsystem

[0114] As can be seen from the simulation results, the power consumed by the deep cooling compression process is much smaller than the power consumed by the normal temperature compression, and the power consumed by the low temperature pump for further compression of the ambient air (134.1K, 4.34MPa) which has entered the supercritical state is much smaller than the power consumed by the low temperature compression. The charging and discharging efficiency of the LAES subsystem in Table 1 is achieved with the assistance of the environmental heat source, and the possible power generated by the LNG-RG subsystem is not taken into account; the key equipment isothermal efficiency is: compressor 85%, expander 90%, cryogenic pump 75%, which is a general assumption parameter in the field.

[0115] Further, the embodiment of the present application also discloses a coupling method of liquid air energy storage and liquefied natural gas regasification, which can be applied to the coupling system of any one of the above, and specifically comprises the following steps:

[0116] In any working condition of the LAES subsystem, the cryogenic energy generated by the LNG-RG subsystem is output to the coupling cold exchange subsystem and stored in the cryogenic tank to realize regasification of the liquefied natural gas.

[0117] In the charging working condition of the LAES subsystem, the compressed heat energy generated by the ambient air through normal-temperature compression is output to the heat storage tank for storage, and then the ambient air entering and exiting each low-temperature compressor is cooled to the cryogenic temperature through the coupling cold exchange subsystem to realize liquefaction of the ambient air.

[0118] In the discharging working condition of the LAES subsystem, the cryogenic energy generated by the LAES subsystem is output to the coupling cold exchange subsystem and stored in the cryogenic tank to realize regasification of the liquid air.

[0119] In some embodiments, the coupling method can further comprise:

[0120] In any working condition of the LAES subsystem, the cryogenic energy generated by the LNG-RG subsystem is output to the coupling cold exchange subsystem and stored in the cryogenic tank to realize regasification of the liquefied natural gas.

[0121] In the discharging working condition of the LAES subsystem, the cryogenic energy generated by the LAES subsystem is output to the coupling cold exchange subsystem and stored in the cryogenic tank to realize regasification of the liquid air.

[0122] In the charging working condition of the LAES subsystem, the ambient air is first cooled to the cryogenic temperature by using the cryogenic energy in the cryogenic tank, and then the ambient air entering and exiting each low-temperature compressor is cooled to the cryogenic temperature by using the cryogenic energy in the cryogenic tank.

[0123] In any working condition of the coupling system, the excess cryogenic energy in the cryogenic tank is output to the external application of the coupling system.

[0124] In some embodiments, the coupling method can further comprise:

[0125] In the discharging working condition of the LAES subsystem, the cryogenic energy generated by the LAES subsystem is output to the coupling cold exchange subsystem and stored in the cryogenic tank to realize regasification of the liquid air.

[0126] In the charging working condition of the LAES subsystem, the ambient air is first cooled to the cryogenic temperature by using the cryogenic energy in the cryogenic tank, and then the ambient air entering and exiting each low-temperature compressor is cooled to the cryogenic temperature by using the cryogenic energy in the cryogenic tank.

[0127] In some embodiments, the coupling method can further comprise:

[0128] When the LAES subsystem is in the charging mode, the ambient air reaching the supercooling temperature enters the cryogenic expander and the liquid air separator in turn, producing liquid air and supercooling return air;

[0129] The supercooling return air is cooled by the supercooling tank to the supercooling temperature.

[0130] The supercooling return air is cooled by the supercooling tank to the supercooling temperature.

[0131] In some embodiments, the coupling method can further include:

[0132] In the charging mode of the LAES subsystem, after the compressed heat energy is output to the heat storage tank, the ambient air is introduced into the air purifier for carbon dioxide and water adsorption treatment, and then the ambient air entering and exiting each cryogenic compressor is cooled to the deep cooling temperature by the coupled cooling subsystem.

[0133] In the discharging mode of the LAES subsystem, at least part of the regasified air discharged by the expander is introduced into the air purifier for carbon dioxide and water desorption treatment.

[0134] It should be understood by those skilled in the art that the embodiments of the coupling method in the embodiments of the present application can be combined with each other.

[0135] In some embodiments, the present application also discloses a coupling method of LAES and LNG-RG to solve the technical problems in the prior art.

[0136] In some illustrative embodiments, the coupling method of LAES and LNG-RG includes: a process of converting ambient air into liquid air for storage in the charging mode, including: ambient air is compressed at room temperature, the compressed heat energy generated by the compression is recovered, the temperature of the ambient air after the room temperature compression is reduced to the ambient temperature, and the ambient air at the target pressure is obtained by multi-stage cryogenic compression; wherein the temperature of the ambient air before and after each stage of cryogenic compression is cooled to the deep cooling temperature by the deep cooling energy in the deep cooling tank; wherein the deep cooling energy in the deep cooling tank comes from the liquefied natural gas regasification process and the liquid air regasification process; wherein the cold end temperature of the deep cooling tank is the deep cooling temperature, and the deep cooling temperature is the pressurized outlet temperature in the liquefied natural gas regasification process; the hot end temperature of the deep cooling tank is the shallow cooling temperature, and the shallow cooling temperature is the outlet temperature of the ambient air after the cryogenic compression of the ambient air.

[0137] In some alternative embodiments, the liquefaction phase transition temperature of the ambient air at the target pressure is higher than the cryogenic temperature; the process of cooling the ambient air before and after each stage of the low-temperature compression to the cryogenic temperature using the cryogenic energy in the cryogenic tank comprises: cooling the ambient air after the last stage of the low-temperature compression to the cryogenic temperature to obtain the liquid air at the target pressure; and the process of converting the ambient air into the liquid air for storage in the charging mode further comprises: compressing the liquid air at the target pressure to a higher pressure and then performing the low-temperature expansion.

[0138] In some alternative embodiments, the process of converting the ambient air into the liquid air for storage in the charging mode further comprises: before cooling the ambient air to the cryogenic temperature using the cryogenic energy in the cryogenic tank, cooling the ambient air to a sub-cryogenic temperature using the sub-cryogenic energy in the sub-cryogenic tank; and the sub-cryogenic energy in the sub-cryogenic tank is from the liquefied natural gas regasification process and the liquid air regasification process.

[0139] In some alternative embodiments, the coupling method further comprises: a process of converting the liquid air into the regasified air for warming expansion in the discharging mode, comprising: recovering the super-cold energy in the regasified air in the liquid air regasification process using the super-cold tank; and the process of converting the ambient air into the liquid air for storage in the charging mode further comprises: cooling the ambient air at the target pressure from the cryogenic temperature to a super-cold temperature; wherein the cold end temperature of the super-cold tank is the super-cold temperature, and the hot end temperature of the super-cold tank is the cryogenic temperature; and the super-cold temperature is the pressurized outlet temperature in the liquid air regasification process.

[0140] In some alternative embodiments, the process of converting the ambient air into the liquid air for storage in the charging mode further comprises: performing the low-temperature expansion on the ambient air at the super-cold temperature to generate the liquid air and super-cold return air; separating and discharging the super-cold return air, and converting the super-cold return air into the return air at the cryogenic temperature by recovering the super-cold energy in the super-cold return air using the super-cold tank; compressing at least part of the return air at the cryogenic temperature, and then cooling the compressed and warmed part of the return air to the cryogenic temperature using the cryogenic energy in the cryogenic tank, and then performing the low-temperature expansion on the cooled part of the return air, and then re-merging the expanded and cooled part of the return air into the separated and discharged super-cold return air.

[0141] In some alternative embodiments, the process of converting the ambient air into the liquid air for storage in the charging mode further comprises: before the multi-stage low-temperature treatment, adsorbing the carbon dioxide and water in the ambient air that has been compressed at room temperature and has the thermal energy recovered by the air purifier; and the process of converting the ambient air into the liquid air for storage in the charging mode further comprises: introducing at least part of the regasified air after the expansion work into the air purifier for desorption treatment of the carbon dioxide and water.

[0142] As shown in FIG. 9, FIG. 9 shows the flow steps of charging and discharging working conditions of the LAES subsystem of the coupling system in the embodiment of the application, including:

[0143] Step S1, normal-temperature compression of ambient air Air to obtain first ambient air Air1;

[0144] Step S2, output of the compression heat energy in the first ambient air Air1 to the heat storage tank HD, so that the temperature of the first ambient air Air1 is reduced to obtain second ambient air Air2;

[0145] Step S3, output of the subcooling energy in the subcooling tank SCD to the second ambient air Air2, so that the temperature of the second ambient air Air2 is reduced to a subcooling temperature to obtain third ambient air Air3;

[0146] The subcooling energy in the subcooling tank SCD can come from the regasified natural gas of the LNG-RG subsystem and the regasified air in the discharging working condition of the LAES subsystem.

[0147] Step S4, multistage low-temperature compression of the third ambient air Air3, so that the third ambient air Air3 is gradually compressed to a target pressure to obtain fourth ambient air Air4;

[0148] The deep cooling energy in the deep cooling tank DCD is output to the third ambient air Air3 before each stage of low-temperature compression, so that the temperature of the third ambient air Air3 is reduced to a deep cooling temperature, and then each stage of low-temperature compression is performed on the third ambient air Air3 at the deep cooling temperature, until the multistage low-temperature compression is completed, and then the fourth ambient air Air4 is cooled to the deep cooling temperature by the deep cooling energy in the deep cooling tank DCD, so that the fourth ambient air Air4 at the deep cooling temperature is obtained.

[0149] The deep cooling energy in the deep cooling tank DCD can come from the regasified natural gas of the LNG-RG subsystem and the regasified air in the discharging working condition of the LAES subsystem.

[0150] In addition to the deep cooling energy in the deep cooling tank DCD, the deep cooling energy generated in real time by the LNG-RG subsystem can also be directly used.

[0151] Step S5, output of the supercooling energy in the supercooling tank UCD to the fourth ambient air Air4, so that the temperature of the fourth ambient air Air4 is reduced to a supercooling temperature to obtain fifth ambient air Air5 at the supercooling temperature, and the supercooling temperature is the pressurized outlet temperature in the regasification process of liquid air;

[0152] Step S6, adiabatic expansion of the fifth ambient air Air5 to obtain sixth ambient air Air6 in the form of gas-liquid mixture in the liquid air separator LAS, and the liquid air therein is stored in the liquid air storage tank LAD.

[0153] The super-cooled reflux air obtained in the liquid air separator LAS can be used to recover the super-cooling energy, deep-cooling energy and shallow-cooling energy of the super-cooled reflux air, and regenerate the super-cooling energy, according to the foregoing embodiments.

[0154] Optionally, the carbon dioxide and water in the second ambient air Air2 can be purified by the air purifier APU before the steps S2 and S3, so as to obtain the second ambient air Air2 without carbon dioxide and water.

[0155] The liquefaction and storage of the ambient air in the charging condition of the LAES subsystem are completed.

[0156] In step S7, the liquid air storage tank LAD releases the liquid air, and the gas-liquid mixed seventh ambient air Air7 is obtained after the liquid air is pressurized by the discharge cryogenic pump DCP.

[0157] In step S8, the super-cooling energy in the regasified air in the gas-liquid mixed air Air6 is recovered by the super-cooling tank UCD, so that the temperature of the regasified air is increased to the deep-cooling temperature, and the eighth ambient air Air8 is obtained.

[0158] In step S9, the deep-cooling energy in the seventh ambient air Air7 is recovered by the deep-cooling tank DCD, so that the temperature of the seventh ambient air Air7 is increased to the shallow-cooling temperature, and the ninth ambient air Air9 is obtained.

[0159] In step S10, the shallow-cooling energy in the ninth ambient air Air9 is recovered by the shallow-cooling tank SCD, so that the temperature of the ninth ambient air Air9 is increased to the ambient temperature, and the tenth ambient air Air10 is obtained.

[0160] In step S11, the compressed heat energy in the heat storage tank HD is output to the tenth ambient air Air10, and the eleventh ambient air Air11 is obtained after the tenth ambient air Air10 is expanded and heated, and the eleventh ambient air Air11 is used to do work by expansion.

[0161] In this step, the compressed heat energy and the ambient heat energy can be output to the tenth ambient air Air10 together, so as to further expand and heat the tenth ambient air Air10.

[0162] The regasification and expansion work of the liquid air in the discharging condition of the LAES subsystem are completed.

[0163] In addition, the LNG-RG subsystem can output the cold energy to the shallow-cooling tank and the deep-cooling tank in the charging condition, the discharging condition and the static condition of the LAES subsystem, without considering the working condition of the LAES subsystem, so as to improve the coupling adaptability of the LNG-RG subsystem and the LAES subsystem.

[0164] The ultra-cold temperature, the deep cold temperature, the shallow cold temperature and the ambient temperature in the embodiments of the present application are mainly used to distinguish the temperature changes in different regions and different states, and in principle, the ultra-cold temperature is lower than the deep cold temperature, the deep cold temperature is lower than the shallow cold temperature, and the shallow cold temperature is lower than the ambient temperature.

[0165] For example, the temperature range of the ultra-cold temperature in the embodiments of the present application can be between-192℃ and-162℃, the temperature range of the deep cold temperature can be between-162℃ and-100℃, the temperature range of the shallow cold temperature can be between-100℃ and-30℃, and the temperature range of the ambient temperature can be between-30℃ and 40℃. In some embodiments of the present application, under the charging working condition of the LAES subsystem, the temperature of the ambient air flowing out of the compressor can be higher than-30℃ by increasing the compression ratio of the compressor; in some embodiments of the present application, the temperatures of the ambient air flowing out of different compressors can be slightly different; these embodiments are all within the scope of protection of the present application and can be obtained by those skilled in the art without making creative efforts.

[0166] In summary, the advantages of the coupling system and the coupling method in the embodiments of the present application include:

[0167] 1. A coupling cold exchange subsystem is established between the LAES subsystem and the LNG-RG subsystem to uniformly manage the deep cold energy and the shallow cold energy, and the following combined functions are realized:

[0168] 1.1. The deep cold energy and the shallow cold energy generated in various working conditions of the LNG-RG subsystem and the LAES subsystem are input into the cold storage tank of the coupling cold exchange subsystem, thereby solving the intermittency problem of the cold energy output of the LNG-RG and ensuring the centralized storage of the deep cold energy and the shallow cold energy;

[0169] 1.2. The centralized output of the deep cold energy is realized, and the deep cold energy of the LNG-RG is used to the greatest extent to manufacture liquid air;

[0170] 1.3. The centralized output of the shallow cold energy is realized, and the excess shallow cold energy of the external application output subsystem is output;

[0171] 1.4. Through the redundant cold energy reserve (for example, after discharging of the LAES subsystem) and the heat energy reserve (for example, after charging of the LAES subsystem) in the coupling cold exchange subsystem, the coupling operation of the LNG-RG subsystem and the LAES subsystem under various working conditions of each other can be met within the redundant capacity range, and the independent operation of the LNG-RG subsystem and the LAES subsystem is also supported, thereby improving the coupling adaptability between the LNG-RG subsystem and the LAES subsystem;

[0172] 1.5, The minimum temperature of the cryogenic energy provided by coupling the cold energy stored in the subsystem with the cold energy output mainly by the LNG-RG subsystem can compress the ambient air, fully utilize the cryogenic energy of the LNG-RG liquefied natural gas regasification, reduce the power consumption of the compressor, and improve the charging and discharging efficiency of the coupling system.

[0173] 2, By the double-temperature compression mode of normal-temperature compression and multi-stage low-temperature compression, the ambient air is compressed to a certain pressure and then cooled to cryogenic temperature before entering the low-temperature compressor; the advantages include:

[0174] 2.1, Primary normal temperature: first, normal-temperature compression can generate compression heat to provide the discharging working condition; the ambient air with a certain compression temperature is convenient for air purification and dehydration of carbon dioxide, and by air purification treatment of the ambient air after recovery of the compression heat, the carbon dioxide and water in the ambient air are prevented from liquefying or freezing in the subsequent process, causing damage to part of the equipment and pipelines.

[0175] 2.2, Multi-stage cryogenic: after primary compression, the main compression process is completed by multi-stage low-temperature compression at a cryogenic temperature, and the cryogenic temperature is the lowest temperature that can be output by the LNG-RG, so as to reduce the overall compression power consumption.

[0176] 3, In the discharging working condition of the LAES subsystem, the cheap or even free ambient heat energy can be maximally utilized to improve the charging and discharging efficiency of the coupling system and reduce the system cost; wherein, the shallow cold energy stored in the coupling cold exchange subsystem can be fully output to external applications without affecting the normal operation of the coupling system.

[0177] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A coupled system of LAES and LNG-RG, characterized in that, Comprise: The LAES subsystem, the LNG-RG subsystem and the coupling cold exchange subsystem; The LAES subsystem comprises: a heat storage tank, and a normal temperature compressor, a multi-stage low temperature compressor group composed of at least two low temperature compressors connected in sequence, a low temperature expander, a liquid air separator, a liquid air storage tank, a discharge low temperature pump and an expander connected in sequence; Wherein, the normal temperature compressor, the multi-stage low temperature compressor group, the low temperature expander, the liquid air separator and the liquid air storage tank connected in sequence form an ambient air liquefaction path for realizing the conversion of ambient air into liquid air; Wherein, the liquid air storage tank, the discharge low temperature pump and the expander connected in sequence form a liquid air regasification path for realizing the conversion of liquid air into regasified air; The coupling cold exchange subsystem supports at least the LNG-RG subsystem to output cold energy to the LAES subsystem, and stores and releases the cold energy of the LNG-RG subsystem and the LAES subsystem; Wherein, the coupling cold exchange subsystem comprises: a cryogenic tank for storing and releasing the cryogenic energy generated by the LNG-RG subsystem and the discharge working condition of the LAES subsystem; the cold end temperature thereof is a cryogenic temperature, and the hot end temperature thereof is a shallow cold temperature; In the charging condition of the LAES subsystem, the ambient air is compressed by the normal temperature compressor and outputs the compression heat energy to the heat storage tank for storage, is cooled to the cryogenic temperature by the coupling cold exchange subsystem, is compressed to the shallow cold temperature by the first stage low temperature compressor, and is cooled to the cryogenic temperature by the coupling cold exchange subsystem to enter the next stage low temperature compressor; Wherein, the cryogenic temperature is the pressurized outlet temperature in the liquefied natural gas regasification process, and the shallow cold temperature is the outlet temperature of the ambient air after low temperature compression.

2. The coupling system of claim 1, wherein, The LNG-RG subsystem further comprises a charging low temperature pump; Wherein, the normal temperature compressor, the multi-stage low temperature compressor group, the charging low temperature pump, the low temperature expander, the liquid air separator and the liquid air storage tank connected in sequence form the ambient air liquefaction path; Wherein, in the charging condition of the LAES subsystem, the ambient air is compressed by the multi-stage low temperature compressor, enters the fully liquefied or supercritical state after being cooled to the cryogenic temperature by the coupling cold exchange subsystem, is compressed to a higher pressure by the charging low temperature pump, is cooled to the cryogenic temperature by the coupling cold exchange subsystem, and then enters the low temperature expander.

3. The coupling system of claim 1, wherein, The LNG-RG subsystem comprises: a liquefied natural gas regasification path for realizing the conversion of liquefied natural gas into regasified natural gas; The coupling cold exchange subsystem further comprises: a cryogenic charging heat exchanger, a cryogenic discharge heat exchanger and a natural gas cryogenic heat exchanger; Wherein, the natural gas cryogenic heat exchanger is arranged on the liquefied natural gas regasification path of the LNG-RG subsystem; Wherein, the cryogenic charging heat exchanger is arranged on the ambient air liquefaction path of the LAES subsystem, and is used for cooling the entering and exiting ambient air of each low temperature compressor to the cryogenic temperature respectively; The deep-cooling discharging heat exchanger is arranged on the liquid air regasification path of the LAES subsystem and is arranged between the discharging cryogenic pump and the expander. The hot end and the cold end of the deep-cooling charging heat exchanger, the deep-cooling discharging heat exchanger and the natural gas deep-cooling heat exchanger are connected with the hot end and the cold end of the deep-cooling tank respectively.

4. The coupling system of claim 1, wherein, The LNG-RG subsystem comprises a liquefied natural gas regasification path for converting the liquefied natural gas into regasified natural gas. The coupling cold-exchange subsystem further comprises a natural gas deep-cooling heat exchanger; the deep-cooling tank is a solid packed bed and has the functions of cold storage and cold exchange simultaneously; Each deep-cooling tank is arranged on the ambient air liquefaction path and the liquid air regasification path of the LAES subsystem simultaneously; in the deep-cooling tank, the ambient air liquefaction path and the liquid air regasification path have the same path and opposite air flow directions. The deep-cooling tank and the low-temperature compressor are arranged at intervals on the ambient air liquefaction path and are used for cooling the ambient air entering and exiting each low-temperature compressor to a deep-cooling temperature. The natural gas deep-cooling heat exchanger is arranged on the liquefied natural gas regasification path of the LNG-RG subsystem. The hot end and the cold end of the natural gas deep-cooling heat exchanger are connected with the hot end and the cold end of each deep-cooling tank respectively.

5. The coupling system of claim 1, wherein, The coupling cold-exchange subsystem further comprises a shallow-cooling tank for storing and releasing the shallow-cooling energy generated by the LNG-RG subsystem and the shallow-cooling energy generated by the LAES subsystem in the discharging mode; the cold end temperature of the shallow-cooling tank is the shallow-cooling temperature and the hot end temperature is the ambient temperature; In any mode of the LAES subsystem, the coupling cold-exchange subsystem outputs the shallow-cooling energy to the external application of the coupling system through the shallow-cooling tank.

6. The coupling system of claim 1, wherein, The LAES subsystem further comprises a super-cooling tank for storing and releasing the super-cooling energy generated by the LAES subsystem in the discharging mode; In the charging mode of the LAES subsystem, the ambient air discharged by the multi-stage low-temperature compressor group is cooled to a deep-cooling temperature by the coupling cold-exchange subsystem, then enters the hot end of the super-cooling tank, the low-temperature expander and the liquid air separator in sequence; the super-cooling return air output by the liquid air separator first enters the cold end of the super-cooling tank; In the discharging mode of the LAES subsystem, the regasification air first outputs the super-cooling energy to the super-cooling tank and then outputs the deep-cooling energy and the shallow-cooling energy to the coupling cold-exchange subsystem; The cold end temperature of the super-cooling tank is a super-cooling temperature and the hot end temperature is a deep-cooling temperature; the super-cooling temperature is the pressurized outlet temperature in the regasification process of the liquid air.

7. The coupling system of claim 6, wherein, Further comprising: a return air compressor and a return air expander; In the charging mode of the LAES subsystem, part of the return air flowing out from the hot end of the super-cooling tank is compressed and heated by the return air compressor, then is cooled to a deep-cooling temperature by the coupling cold-exchange subsystem, then is expanded and cooled by the return air expander, and then is mixed into the super-cooling return air output from the liquid air separator.

8. The coupling system of claim 1, wherein, Further comprising: An external heat source providing external thermal energy; in the discharging mode of the LAES subsystem, the regenerator tank and the external heat source jointly provide the compressed thermal energy and the external thermal energy to the regasified air.

9. The coupling system of claim 1, wherein, the cryogenic tank of the coupling cold exchange subsystem is a solid packed bed, and the heat exchange device of the coupling cold exchange subsystem is a heat exchanger; the solid packed bed and the heat exchanger exchange cold energy through a heat exchange medium; or, the cryogenic tank and the heat exchange device of the coupling cold exchange subsystem are integrated in a solid packed bed structure, and the ambient air exchanges cold energy with the cold storage medium in the solid packed bed through the pipe wall of the flow pipeline.

10. The coupling system of claim 1, wherein, the cryogenic tank of the coupling cold exchange subsystem includes a hot-end adiabatic container and a cold-end adiabatic container, the heat exchange device of the coupling cold exchange subsystem is a heat exchanger, the hot end and the cold end of the heat exchanger are connected to the hot-end adiabatic container and the cold-end adiabatic container respectively, and the adiabatic containers are filled with liquid heat exchange medium, and the storage and exchange of cold energy between the two adiabatic containers are realized through the liquid heat exchange medium.

11. The coupling system of claim 1, wherein, Further comprising: an air purifier arranged on the ambient air liquefaction path of the LAES subsystem and between the ambient air compressor and the multi-stage low-temperature compressor group; wherein, in the charging mode of the LAES subsystem, the ambient air is compressed by the ambient air compressor, the compressed thermal energy is recovered by the regenerator tank, and then the ambient air enters the air purifier, is purified, and is cooled to a cryogenic temperature by the coupling cold exchange subsystem and enters the multi-stage low-temperature compressor group; wherein, in the discharging mode of the LAES subsystem, the regasified air output by the expander at least partially flows through the air purifier and is then discharged to the environment.

12. A method of coupling of a LAES and a LNG-RG, characterized in that, Further comprising: a process of converting ambient air into liquid air for storage in the charging mode, comprising: ambient air is compressed at ambient temperature, and the compressed thermal energy generated by the compression is recovered, so that the temperature of the ambient air after ambient temperature compression is reduced to ambient temperature, and then the ambient air is compressed at low temperature to obtain ambient air at a target pressure; wherein, the temperature of the ambient air before and after each stage of low-temperature compression is cooled to a cryogenic temperature by the cryogenic energy in the cryogenic tank; wherein, the cryogenic energy in the cryogenic tank comes from the liquefied natural gas regasification process and the liquid air regasification process; wherein, the cold end temperature of the cryogenic tank is a cryogenic temperature, and the cryogenic temperature is the pressurized outlet temperature in the liquefied natural gas regasification process; the hot end temperature of the cryogenic tank is a shallow cold temperature, and the shallow cold temperature is the outlet temperature of the ambient air after low-temperature compression.

13. The coupling method of claim 12, wherein, The process of converting ambient air into liquid air for storage in the charging mode further comprises: before the temperature of the ambient air is cooled to a cryogenic temperature by the cryogenic energy in the cryogenic tank, the temperature of the ambient air is cooled to a shallow cold temperature by the shallow cold energy in the shallow cold tank; wherein, the shallow cold energy in the shallow cold tank comes from the liquefied natural gas regasification process and the liquid air regasification process.

14. The coupling method of claim 12, wherein, Further comprising: a process of converting liquid air into regasified air for warming and expanding in the discharging mode, comprising: The supercooling energy in the regasification air in the liquid air regasification process is recovered by using a supercooling tank; The process of converting ambient air into liquid air for storage under the charging condition further comprises: cooling the ambient air at the target pressure from a deep cooling temperature to a supercooling temperature; The cold end temperature of the supercooling tank is the supercooling temperature, and the hot end temperature is the deep cooling temperature; the supercooling temperature is the pressurized outlet temperature in the liquid air regasification process.

15. The coupling method of claim 14, wherein, The process of converting ambient air into liquid air for storage under the charging condition further comprises: carrying out low-temperature expansion on the ambient air at the supercooling temperature to generate liquid air and supercooling return air; separating and discharging the supercooling return air and recovering the supercooling energy in the supercooling return air by using the supercooling tank to convert it into deep cooling temperature return air; compressing at least part of the deep cooling temperature return air, cooling the compressed and warmed part of the return air to the deep cooling temperature by using the deep cooling energy in the deep cooling tank, and then carrying out low-temperature expansion on the cooled part of the return air, and then re-merging the expanded and cooled part of the return air into the separated and discharged supercooling return air.

16. The coupling method of claim 12, wherein, The process of converting ambient air into liquid air for storage under the charging condition further comprises: absorbing carbon dioxide and water in the ambient air compressed at normal temperature and recovered in heat energy by using an air purifier before the multi-stage low-temperature treatment; The process of converting ambient air into liquid air for storage under the charging condition further comprises: introducing at least part of the regasification air after expansion and work into the air purifier for desorption treatment of carbon dioxide and water.

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