Liquid air energy storage system and method

Abstract

The present invention discloses a liquid air energy storage system and method, relating to the field of large-scale energy storage technology; the system sequentially pressurizes the liquid air under the LAES system discharge condition through multiple discharge cryogenic pumps to reach the discharge target pressure before the liquid air is regasified, avoiding the loss of high-quality cold energy caused by pressurizing the liquid air to the discharge target pressure at one time, so that relatively higher quality cold energy can be obtained after the first pressurization. At the same time, by using a low-temperature compressor under the LAES charging condition and cooling the ambient air before and after the low-temperature compressor to a cryogenic temperature, the compression power can be greatly reduced, thereby improving the overall charging and discharging efficiency of the LAES system.

Description

Technical Field

[0001] The present invention belongs to the field of large-scale energy storage technology, and in particular relates to a liquid air energy storage system and method with high charging and discharging efficiency. Background Art

[0002] Liquid Air Energy Storage (LAES), as a type of energy storage technology, uses cheap valley electricity to absorb air from the environment, then cools it until it becomes liquid for storage; during peak electricity consumption, the liquid air is released and the pressure and temperature are increased, and then it enters the expander to generate work and generate electricity, realizing valley electricity peak utilization, which can play an important role in peak regulation of the power grid.

[0003] To ensure the LAES system's charge and discharge efficiency, the high- and low-quality cold energy released from the liquid air during LAES discharge is recovered for subsequent air liquefaction during LAES charging. Typically, the released atmospheric liquid air is directly pressurized to the target discharge pressure, and the cold energy released during the regasification process is then recovered at this target discharge pressure.

[0004] The LNG-RG regasification process releases a significant amount of cold energy, which can be incorporated into the LAES system to increase the air liquefaction ratio during charging and improve the LAES system's charge and discharge efficiency. Typically, the released LNG is directly pressurized to the target regasification pressure, and the cold energy released during the regasification process is then recovered at this target pressure.

[0005] The target pressure for regasification of liquid air is usually around 8 MPa. If the target pressure is too low, it will negatively affect the discharge power, thereby reducing the charging and discharging efficiency. If the target pressure is too high, it will negatively affect the high-quality cold energy output by the regasification process, which may lead to a decrease in the liquefaction rate of the ambient air under LAES charging conditions and an increase in the proportion of return air at normal pressure, which will also reduce the charging and discharging efficiency.

[0006] The target pressure for regasification of LNG entering the natural gas transmission pipeline network is usually 10MPa; some designs will first pressurize the LNG to 20MPa, and then expand the LNG to perform work during the regasification process through the pressure difference between 20MPa and 10MPa.

[0007] However, the liquid-to-gas phase transition temperature of liquid air and liquefied natural gas at atmospheric pressure is very low. Cold energy near this temperature is high-quality cold energy and a scarce resource in LAES systems. After pressurization, the cold energy output characteristics of liquid air and liquefied natural gas undergo significant changes: their phase transition temperature increases, the change in specific heat capacity slows, and the quality of the cold energy output decreases. Existing pressurization methods fail to fully account for these factors, leaving significant room for improvement. Summary of the Invention

[0008] In view of this, one object of the present invention is to propose a liquid air energy storage system to solve the problem of quality loss of cold energy recovery in the liquid air energy storage system in the prior art, resulting in poor charging and discharging efficiency of the system.

[0009] In some illustrative embodiments, the liquid air energy storage system includes: a cryogenic compressor, a cryogenic expander, at least two discharge cryogenic pumps, an air super-cold discharge heat exchanger, an air super-cold charge heat exchanger, an air super-cold tank, an air super-cold medium, a cryogenic discharge heat exchanger, a cryogenic charge heat exchanger, a cryogenic tank, and a cryogenic medium;

[0010] Among them, under LAES discharge conditions,

[0011] The liquid air is pressurized sequentially by the at least two discharge cryogenic pumps to reach a discharge target pressure before the liquid air is regasified; after the liquid air is pressurized by the first discharge cryogenic pump, the air super-cold medium is cooled to an air super-cold temperature by the air super-cold discharge heat exchanger; the air super-cold medium at the air super-cold temperature enters the air super-cold tank for storage; after the liquid air is pressurized by the second discharge cryogenic pump, the cryogenic medium is cooled to a cryogenic temperature by the cryogenic discharge heat exchanger; the cryogenic medium at the cryogenic temperature enters the cryogenic tank for storage;

[0012] Among them, under LAES charging conditions,

[0013] The ambient air is compressed by the low-temperature compressor to the charging target pressure before the ambient air is liquefied; before and after the ambient air enters the low-temperature compressor, the ambient air is cooled to a cryogenic temperature by using a cryogenic medium at a cryogenic temperature through a cryogenic charging heat exchanger; the ambient air at the cryogenic temperature that reaches the charging target pressure is further cooled to an air super-cold temperature by using an air super-cold medium at an air super-cold temperature through an air super-cold charging heat exchanger; the ambient air at the air super-cold temperature is converted into liquid air at normal pressure by the low-temperature expander.

[0014] In some optional embodiments, the liquid air energy storage system further includes: an LNG super-cold charging heat exchanger, an LNG super-cold tank, an LNG super-cold medium, and a natural gas regasification subsystem; the natural gas regasification subsystem includes: at least two LNG cryogenic pumps, an LNG super-cold heat exchanger, and an LNG cryogenic heat exchanger;

[0015] Among them, under LNG regasification conditions,

[0016] The LNG is pressurized sequentially by the at least two LNG cryogenic pumps to reach a target LNG pressure before LNG regasification; after the LNG is pressurized by the first LNG cryogenic pump, the LNG super-cold medium is cooled to an LNG super-cold temperature by the LNG super-cold heat exchanger; the LNG super-cold medium at the LNG super-cold temperature is stored in the LNG super-cold tank; after the LNG is pressurized by the second LNG cryogenic pump, the LNG is cooled to a cryogenic temperature by the LNG cryogenic heat exchanger; the cryogenic medium at the cryogenic temperature is stored in the cryogenic tank;

[0017] Among them, under the LAES discharge condition, before the ambient air at the cryogenic temperature that reaches the charging target pressure is cooled to the air super-cold temperature, the ambient air is first cooled to the LNG super-cold temperature using the LNG super-cold medium at the LNG super-cold temperature through the LNG super-cold charging heat exchanger;

[0018] The LNG super-cold temperature is lower than the cryogenic temperature and higher than the air super-cold temperature.

[0019] In some optional embodiments, the discharge target pressure is higher than the charge target pressure.

[0020] In some optional embodiments, the low-temperature compressor includes multiple low-temperature compressors, and the cryogenic charging heat exchanger includes multiple cryogenic charging heat exchangers, wherein the ambient air is compressed in sequential stages by the multiple low-temperature compressors to reach the target charging pressure, and the ambient air is cooled to a cryogenic temperature by using a cryogenic medium at a cryogenic temperature through the cryogenic charging heat exchanger before and after entering each stage of the low-temperature compressor.

[0021] In some optional embodiments, the air super-cold tank, LNG super-cold tank, and cryogenic tank are respectively a pair of insulated low-pressure containers; the temperatures of the media stored in the cold end containers of the air super-cold tank, LNG super-cold tank, and cryogenic tank are respectively the air super-cold temperature, the LNG super-cold temperature, and the cryogenic temperature; the air super-cold temperature is lower than the LNG super-cold temperature, and the LNG super-cold temperature is lower than the cryogenic temperature.

[0022] In some optional embodiments, an LNG expander is further included, wherein the LNG target pressure is higher than the pressure of the natural gas after regasification entering the natural gas pipeline network, and the pressure difference between the LNG target pressure and the pipeline pressure is used to perform work through the LNG expander.

[0023] In some optional embodiments, the air super-cooled discharge heat exchanger and / or the LNG super-cooled heat exchanger is a plate heat exchanger structure.

[0024] In some optional embodiments, the number of the LNG cryogenic pumps is 3.

[0025] In some optional embodiments, the cryogenic charging heat exchanger includes: an LNG cryogenic charging heat exchanger located at the inlet of the cryogenic compressor, and an air cryogenic charging heat exchanger located at the outlet of the cryogenic compressor; the cryogenic tank includes: an air cryogenic tank and an LNG cryogenic tank that are independent of each other; the cryogenic discharge heat exchanger is an air cryogenic discharge heat exchanger; the cryogenic medium includes: an air cryogenic medium and an LNG cryogenic medium;

[0026] Among them, under LAES discharge conditions,

[0027] After the liquid air is pressurized by the second discharge cryogenic pump, the air cryogenic medium is cooled to an air cryogenic temperature through an air cryogenic discharge heat exchanger; the air cryogenic medium at the air cryogenic temperature enters the air cryogenic tank for storage;

[0028] Among them, under LNG regasification conditions,

[0029] After the LNG is pressurized by the second LNG cryogenic pump, the LNG cryogenic medium is cooled to the LNG cryogenic temperature through the LNG cryogenic heat exchanger; the LNG cryogenic medium at the LNG cryogenic temperature enters the LNG cryogenic tank for storage; wherein the air cryogenic temperature is lower than the LNG cryogenic temperature;

[0030] Among them, under the LAES discharge condition, the ambient air is cooled to a cryogenic temperature by using a cryogenic medium at a cryogenic temperature through a cryogenic charging heat exchanger before and after entering the cryogenic compressor, specifically including: before and after entering the cryogenic compressor, the ambient air is cooled to an LNG cryogenic temperature by using an LNG cryogenic medium at an LNG cryogenic temperature through a LNG cryogenic charging heat exchanger and / or cooled to an air cryogenic temperature by using an air cryogenic medium at an air cryogenic temperature through an air cryogenic charging heat exchanger.

[0031] Another object of the present invention is to propose a liquid air energy storage method to solve the technical problems in the prior art.

[0032] In some illustrative embodiments, the liquid air energy storage method includes: a LAES discharge condition and a LAES charging condition;

[0033] Under the LAES discharge condition, the liquid air undergoes the following steps: C1, the liquid air is pressurized by the first discharge cryogenic pump; C2, the liquid air passes through the air super-cold discharge heat exchanger to cool the air super-cold medium to the air super-cold temperature; wherein, the air super-cold medium at the air super-cold temperature enters the air super-cold tank for storage; C3, the liquid air is pressurized by the second discharge cryogenic pump to reach the discharge target pressure before the liquid air is re-gasified; C4, the liquid air passes through the cryogenic discharge heat exchanger to cool the cryogenic medium to the cryogenic temperature; wherein, the cryogenic medium at the cryogenic temperature enters the cryogenic tank for storage;

[0034] Under the LAES charging condition, the ambient air undergoes the following steps: D1. The ambient air is compressed by a cryogenic compressor to the charging target pressure before the ambient air is liquefied; wherein, before and after the ambient air enters the cryogenic compressor, the ambient air is cooled to a cryogenic temperature using a cryogenic medium at a cryogenic temperature through a cryogenic charging heat exchanger; D2. The ambient air at the cryogenic temperature that has reached the target charging pressure is further cooled to an air super-cold temperature using an air super-cold medium at an air super-cold temperature through an air super-cold charging heat exchanger; D3. The ambient air at the air super-cold temperature is converted into liquid air at normal pressure through a cryogenic expander;

[0035] Among them, the cold end temperature of the air super-cold tank is the air super-cold temperature, and the cold end temperature of the cryogenic tank is the cryogenic temperature; the air super-cold temperature is lower than the cryogenic temperature.

[0036] In some illustrative embodiments, the liquid air energy storage method further includes: LNG regasification conditions;

[0037] Under LNG regasification conditions, LNG undergoes the following steps: L1, LNG is pressurized by a first LNG cryogenic pump; L2, LNG is cooled to a super-cold LNG temperature by an LNG super-cold heat exchanger; wherein, the super-cold LNG at the super-cold LNG temperature enters an LNG super-cold tank for storage; L3, LNG is pressurized by a second LNG cryogenic pump to reach a target LNG pressure before LNG regasification; L4, LNG is cooled to a cryogenic temperature by an LNG cryogenic heat exchanger; wherein, the cryogenic temperature enters the cryogenic tank for storage;

[0038] Among them, under the LAES discharge condition, the D2 includes: D2-1, first cooling the ambient air at the cryogenic temperature that reaches the charging target pressure to the LNG super-cold temperature through the LNG super-cold charging heat exchanger using the LNG super-cold medium at the LNG super-cold temperature; D2-2, the ambient air at the LNG super-cold temperature is further cooled to the air super-cold temperature through the air super-cold charging heat exchanger using the air super-cold medium at the air super-cold temperature; wherein, the LNG super-cold temperature is lower than the cryogenic temperature and higher than the air super-cold temperature.

[0039] In some demonstrative embodiments, the discharge target pressure is higher than the charge target pressure.

[0040] Compared with the existing technology, this application has the following advantages:

[0041] In the embodiment of the present invention, multiple discharge cryogenic pumps are used to sequentially pressurize the liquid air under the LAES system discharge condition to reach the discharge target pressure before the liquid air is regasified, avoiding the loss of high-quality cold energy caused by pressurizing the liquid air to the discharge target pressure at one time, so that relatively higher quality cold energy can be obtained after the first pressurization. At the same time, by using a low-temperature compressor under the LAES charging condition and cooling the ambient air before and after the low-temperature compressor to a deep-cold temperature, the compression power can be greatly reduced, thereby improving the overall charging and discharging efficiency of the LAES system. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a structural example 1 of the liquid air energy storage system in an embodiment of the present invention;

[0043] Figure 2 This is a second structural example of the liquid air energy storage system in an embodiment of the present invention;

[0044] Figure 3 It shows some unit nodes of embodiment 2 of the present invention.

[0045] Figure 1 Description of the markup in:

[0046] Normal temperature compressor C1 (Compressor 1), heat exchanger charging heat exchanger XC-H (Heat Exchanger Charging - Hot), air purifier APU (Air Purification Unit), shallow cooling charging heat exchanger XC-SC (Heat Exchanger Charging - Shallow Cold), first deep cooling charging heat exchanger XC1-DC (Heat Exchanger Charging 1 - Deep Cold), first low-temperature compressor C2 (Compressor 2), second deep cooling charging heat exchanger XC2-DC (Heat Exchanger Charging 2 - Deep Cold), second low-temperature compressor C3 (Compressor 3), third deep cooling charging heat exchanger XC3-DC (Heat Exchanger Charging 3 - Deep Cold), third low-temperature compressor C4 (Compressor 4), fourth deep cooling charging heat exchanger XC4-DC (Heat Exchanger Charging 4 - Deep Cold), LNG ultra-cold charging heat exchanger XC-LUC (Heat Exchanger Charging - LNG Ultra Cold), air ultra-cold charging heat exchanger XC-AUC (Heat Exchanger Charging - Deep Cold) Exchanger Charging - Air Ultra Cold), Cryogenic Pump (CE), Liquid Air Separator (LAS), Liquid Air Dewar (LAD), Discharge Cryogenic Pump 1 (DCP1), Heat Exchanger Discharging - Air Ultra Cold (XD-AUC), Discharge Cryogenic Pump 2 (DCP2), Heat Exchanger Discharging - Deep Cold (XD-DC), Heat Exchanger Discharging - Shallow Cold (XD-SC), Heat Exchanger Discharging - Hot (XD-H), Expander 1 (E1), Hot Dewar 1 (D1-H),Cold end D2-H (Hot Dewar 2)), Shallow Cold Tank (Hot end D1-SC (Shallow Cold Dewar 1), Cold end D2-SC (Shallow Cold Dewar 2)), Cryogenic Tank (Hot end D1-DC (Deep Cold Dewar 1), Cold end D2-DC (DeepCold Dewar 2)), LNG Ultra Cold Tank (Hot end D1-LUC (LNG Ultra Cold Dewar 1), Cold end D2-LUC (LNGUltra Cold Dewar 2)), Air Ultra Cold Tank (Hot end D1-AUC (Air Ultra Cold Dewar 1), Cold end D2-AUC (Air Ultra Cold Dewar 2)), First LNG Cryogenic Pump LCP1 (LNG Cryogenic Pump 1), LNG Ultra Cold Heat Exchanger XL-LUC, Second LNG Cryogenic Pump LCP2 (LNG Cryogenic Pump 2), LNG Cryogenic Heat Exchanger XL-DC (LNG HeatExchanger-Deep Cold), Third LNG Cryogenic Pump LCP3 (LNG Cryogenic Pump3), LNG shallow cold heat exchanger XL-SC (LNG Heat Exchanger-Shallow Cold) and LNG expander EL (LNG Expander).

[0047] Figure 2 Supplementary marking instructions in:

[0048] First LNG deep-cold charging heat exchanger XC1-LDC (Heat Exchanger Charging 1-LNG DeepCold), second LNG deep-cold charging heat exchanger XC2-LDC (Heat Exchanger Charging 2-LNG Deep Cold), third LNG deep-cold charging heat exchanger XC3-LDC (Heat Exchanger Charging 3-LNG Deep Cold), fourth air deep-cold charging heat exchanger XC4-ADC (Heat Exchanger Charging 4-Air Deep Cold), LNG deep-cold tank (hot end D1-LDC (LNG Deep Cold Dewar 1), cold end D2-LDC (LNG Deep Cold Dewar 2)), air deep-cold tank (hot end D1-ADC (Air Deep Cold Dewar 1), cold end D2-ADC (Air Deep Cold Dewar 2)), air deep-cold discharge heat exchanger XD-ADC (Heat Exchanger Discharging-Air Deep Cold). DETAILED DESCRIPTION

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0050] Unless otherwise defined in the present invention, the technical or scientific terms used in the present invention should have the usual meaning understood by people with ordinary skills in the field to which the present invention belongs. Unless clearly described in words in the present invention, the "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. In order to keep the following description of the embodiments of the present invention clear and concise, the present invention omits detailed descriptions of known functions, known components, or common knowledge. In the absence of conflict, the various technical features in the embodiments of the present invention can be combined with each other, and the combined embodiments still fall within the scope of protection of the present invention.

[0051] To improve the overall charge and discharge efficiency of a liquid air energy storage system (LAES), the following design objectives must be met as closely as possible: 1. For the ambient air prior to cryogenic expansion during LAES charging: A. Ensure the highest possible pressure; B. Ensure the lowest possible temperature; C. Ensure the lowest possible compression power. 2. For the liquid air during LAES discharging: D. Ensure the highest possible pressurization of the liquid air prior to regasification to generate more expansion work; E. Ensure the lowest possible temperature of the cold energy released during regasification, thereby minimizing the temperature of the ambient air prior to entering the cryogenic expander for cryogenic expansion during LAES charging.

[0052] Among them, the combination of A and B can increase the liquefaction ratio of liquid air, while the purpose of C is to reduce the power consumption of system charging. E is the main prerequisite for B. A and C conflict with each other, and D and E conflict with each other. Therefore, how to coordinate the above A, B, C, D, and E is an important optimization goal to improve the charging and discharging efficiency of LAES.

[0053] In the existing technology, under LAES discharge conditions, the released liquid air is usually pressurized at one time to reach the discharge target pressure before the liquid air is regasified under the discharge condition. Then, the cold energy released during the regasification process of the liquid air is recovered at this discharge target pressure. However, since the pressurization process will cause the temperature of the liquid air to rise, the greater the pressure, the higher the temperature, which will cause the quality and total amount of cold energy recovered to decrease. This is the main problem of the conflict between D and E.

[0054] In this regard, the present invention proposes a system and method for liquid air energy storage. Under the system discharge condition, the liquid air before regasification is pressurized twice or even multiple times in sequence to gradually make the liquid air reach the discharge target pressure before the liquid air is regasified, so that relatively higher quality (relatively lower temperature) cold energy can be obtained after the first pressurization, and the subsequent pressurization ensures that the liquid air can reach the discharge target pressure before the liquid air is regasified under the discharge condition, thereby resolving the conflict between D and E and achieving the B target at the same time; at the same time, under the LAES charging condition, through low-temperature compression, the realization of the A and C targets can be taken into account at the same time.

[0055] The embodiment of the present invention discloses a liquid air energy storage system, specifically, as Figure 1 As shown, Figure 1 This is a structural example 1 of the liquid air energy storage system in an embodiment of the present invention; the liquid air energy storage system includes: a low-temperature compressor (such as C2, C3, C4), a low-temperature expander CE, at least two discharge cryogenic pumps (such as a first discharge cryogenic pump DCP1, a second discharge cryogenic pump DCP2), an air ultra-cold discharge heat exchanger XD-AUC, an air ultra-cold charging heat exchanger XC-AUC, an air ultra-cold tank (cold end D1-AUC, hot end D2-AUC), an air ultra-cold medium, a cryogenic discharge heat exchanger XD-DC, a cryogenic charging heat exchanger (such as XC1-DC, XC2-DC, XC3-DC, XC4-DC), a cryogenic tank (cold end D1-DC, hot end D2-DC), a cryogenic medium and a liquid air storage tank LAD.

[0056] Under the LAES discharge condition, the liquid air released from the liquid air storage tank LAD is pressurized sequentially by two or more discharge cryopumps to reach the discharge target pressure before the liquid air is re-gasified; during the process, the liquid air is first pressurized once by the first discharge cryopump DCP1 and then enters the air ultra-cold discharge heat exchanger XD-AUC, and exchanges cold energy with the air ultra-cold medium in the air ultra-cold discharge heat exchanger XD-AUC to cool the air ultra-cold medium to the air ultra-cold temperature. The air ultra-cold medium cooled to the air ultra-cold temperature enters the air ultra-cold tank to realize the storage of air ultra-cold energy; then the liquid air is pressurized for the second time by the second discharge cryopump DCP2 and then enters the cryogenic discharge heat exchanger XD-DC, and exchanges cold energy with the cryogenic medium in the cryogenic discharge heat exchanger XD-DC to cool the cryogenic medium to the cryogenic temperature DCT. The cryogenic medium cooled to the cryogenic temperature DCT enters the cryogenic tank to realize the storage of cryogenic energy;

[0057] In some embodiments, under LAES discharge conditions, the super-cold air medium is drawn from the hot end D2-AUC of the super-cold air tank and enters the super-cold air discharge heat exchanger XD-AUC. After exchanging cold energy with liquid air, it is then discharged from the super-cold air discharge heat exchanger XD-AUC and enters the cold end D1-AUC of the super-cold air tank for storage. Similarly, under LAES discharge conditions, the cryogenic medium is drawn from the hot end D2-DC of the cryogenic tank and enters the cryogenic discharge heat exchanger XD-DC. After exchanging cold energy with liquid air, it is then discharged from the super-cold air discharge heat exchanger XD-DC and enters the cold end D1-AUC of the cryogenic tank for storage.

[0058] In the above-mentioned LAES discharge condition, since the pressure of the liquid air after the first pressurization is lower than the discharge target pressure before the liquid air is regasified, the super-cold energy of air with higher cold energy quality can be recovered, which can further reduce the temperature of the ambient air before low-temperature expansion in the LAES charging condition, thereby improving the overall charging and discharging efficiency.

[0059] Among them, in order to avoid the regasification of liquid air during the process of air super-cold energy and cryogenic energy recovery, the temperature of the liquid air after air super-cold energy recovery is lower than the liquid-to-gas phase transition temperature of the liquid air after the first pressurization; similarly, the temperature of the liquid air after cryogenic energy recovery is lower than the liquid-to-gas phase transition temperature of the liquid air after the second pressurization.

[0060] In addition, after the liquid air completes cold energy recovery under the LAES discharge condition, it is regasified and the kinetic energy of the regasified air is converted into electrical energy for power generation through the expander E1. Typically, multi-stage expansion is used for power generation. Multi-stage expansion is common knowledge in the field and is not the focus of the present invention. Its description is omitted here.

[0061] Under the LAES charging condition, the ambient air is compressed by the cryogenic compressor (such as C2, C3, and C4) to the charging target pressure before the ambient air is liquefied; wherein, before and after the ambient air enters the cryogenic compressor (such as C2, C3, and C4) for cryogenic compression, it exchanges cold energy with the cryogenic medium in the cryogenic charging heat exchanger (such as XC1-DC, XC2-DC, XC3-DC, and XC4-DC), and the ambient air is cooled to the cryogenic temperature DCT by using the cryogenic medium with cryogenic energy DCE. The ambient air that has been cryogenically compressed and cooled to the cryogenic temperature DCT enters the air ultra-cold charging heat exchanger XC-AUC, and further exchanges cold energy with the air ultra-cold medium in the air ultra-cold charging heat exchanger XC-AUC, and the ambient air is cooled from the cryogenic temperature to the air ultra-cold temperature AUCT by using the air ultra-cold medium with air ultra-cold energy AUCE. Finally, the ambient air cooled to the air ultra-cold temperature AUCT enters the cryogenic expander CE to be converted into liquid air at normal pressure, and then enters the liquid air storage tank LAD for storage.

[0062] In some embodiments, under LAES charging conditions, the ultra-cold air medium is drawn from the ultra-cold air tank cold end D1-AUC into the ultra-cold air charging heat exchanger XC-AUC. After exchanging cold energy with liquid air, it is then discharged from the ultra-cold air charging heat exchanger XC-AUC and stored in the ultra-cold air tank hot end D2-AUC. Similarly, the cryogenic medium is drawn from the cryogenic tank cold end D1-DC into the cryogenic charging heat exchanger XC-DC. After exchanging cold energy with liquid air, it is then discharged from the cryogenic charging heat exchanger XC-DC and stored in the cryogenic tank hot end D2-DC.

[0063] In the above-mentioned LAES charging condition, the compression power can be greatly reduced by using a low-temperature compressor and cooling the temperature of the ambient air before and after the low-temperature compressor to a cryogenic temperature.

[0064] In the embodiment of the present invention, multiple discharge cryogenic pumps are used to sequentially pressurize the liquid air under the LAES system discharge condition to reach the discharge target pressure before the liquid air is regasified, avoiding the loss of high-quality cold energy caused by pressurizing the liquid air to the discharge target pressure at one time, so that relatively higher quality cold energy can be obtained after the first pressurization. At the same time, by using a low-temperature compressor under the LAES charging condition and cooling the ambient air before and after the low-temperature compressor to a deep-cold temperature, the compression power can be greatly reduced, thereby improving the overall charging and discharging efficiency of the LAES system.

[0065] In some embodiments, the low-temperature compressor in the embodiments of the present invention may be a multi-stage low-temperature compressor group consisting of multiple low-temperature compressors (e.g., a first low-temperature compressor C2, a second low-temperature compressor C3, and a third low-temperature compressor C4), and the cryogenic charging heat exchanger includes multiple cryogenic charging heat exchangers (e.g., a first cryogenic charging heat exchanger XC1-DC, a second cryogenic charging heat exchanger XC2-DC, a third cryogenic charging heat exchanger XC3-DC, and a fourth cryogenic charging heat exchanger XC4-DC);

[0066] The ambient air is compressed in multiple stages through a plurality of low-temperature compressors in sequence to reach the charging target pressure. Before and after the ambient air enters each stage of the low-temperature compressor, the ambient air is cooled to a cryogenic temperature by using a cryogenic medium at a cryogenic temperature through a cryogenic charging heat exchanger.

[0067] The number of cryogenic charging heat exchangers should be greater than the number of cryogenic compressors, so that the ambient air before and after the cryogenic compressors can be cooled. Preferably, the number of cryogenic charging heat exchangers is one greater than the number of cryogenic compressors, meaning that one cryogenic charging heat exchanger is provided at the inlet of each stage of cryogenic compressors, and one cryogenic charging heat exchanger is provided at the outlet of the last stage of cryogenic compressors.

[0068] In this embodiment, deep cold energy is fully utilized to realize multi-stage low-temperature compression under the charging condition of the LAES system, which can greatly improve the low-temperature compression efficiency and reduce the power consumption of the air compression process.

[0069] In some embodiments, the liquid air energy storage system in the embodiment of the present invention may further include: a normal temperature compressor C1, which is used to first compress the ambient air at normal temperature before compressing the ambient air at low temperature during the LAES charging process, thereby increasing the pressure of the ambient air.

[0070] In some embodiments, the liquid air energy storage system of the present invention may further include: a thermal storage charging heat exchanger XC-H, a thermal storage discharging heat exchanger XD-H, a thermal storage tank (e.g., hot end D2-H, cold end D1-H), and a heat exchange medium; wherein, under the LAES charging condition, the heat exchange medium obtains compression heat energy from ambient air compressed at room temperature in the thermal storage charging heat exchanger XC-H and stores it in the thermal storage tank to achieve compression heat energy storage; and under the LAES discharging condition, the heat exchange medium outputs compression heat energy to the regasified air in the thermal storage discharging heat exchanger XD-H, thereby increasing the expansion temperature of the regasified air and increasing its kinetic energy. wherein, under the LAES charging condition, the heat exchange medium is discharged from the thermal storage tank cold end D1-H into the thermal storage charging heat exchanger HC-H, and after exchanging heat energy with the ambient air, enters the thermal storage tank hot end D2-H; under the LAES discharging condition, the flow direction is reversed.

[0071] In some embodiments, the liquid air energy storage system in the embodiments of the present invention can also use an external heat source to further increase the expansion temperature of the regasified air under discharge conditions; wherein the external heat source is not limited to ambient heat sources such as ambient air and seawater, solar energy, or industrial waste heat.

[0072] Furthermore, under the charging condition, the external heat energy provided by the external heat source and the compression heat energy in the heat storage tank can be jointly output to the regasified air.

[0073] In some embodiments, the liquid air energy storage system in the embodiments of the present invention may further include: a shallow cooling charging heat exchanger XC-SC, a shallow cooling discharging heat exchanger XD-SC, a shallow cooling tank (e.g., a hot end D2-SC, a cold end D1-SC), and a shallow cooling medium; wherein, under the LAES charging condition, the shallow cooling medium cools the ambient air to a shallow cooling temperature SCT in the shallow cooling charging heat exchanger. Under the LAES discharging condition, the shallow cooling medium is cooled to a shallow cooling temperature SCT by liquid air in the shallow cooling discharging heat exchanger and then enters the shallow cooling tank, thereby storing shallow cooling energy SCE. The flow direction of the shallow cooling medium under the LAES charging and discharging conditions is as described above and will not be repeated here.

[0074] In some embodiments, the liquid air energy storage system in the embodiments of the present invention may further include: an air purifier APU, which is used to adsorb and remove impurities such as carbon dioxide and water in the ambient air during the charging process. Preferably, the air purifier can be arranged between the normal temperature compressor C1 and the low temperature compressor (such as C2, C3, C4). Furthermore, the air purifier APU can be arranged between the thermal storage charging heat exchanger XC-H and the low temperature compressor (such as C2, C3, C4).

[0075] Among them, the principle of the air purifier APU to remove carbon dioxide and water from the ambient air can be to adsorb carbon dioxide and water in the ambient air through molecular sieves. Therefore, under the discharge condition of the LAES subsystem, at least part of the regasified air output by the expander E1 can be passed through the air purifier and discharged into the environment. This part of the ambient air is used to complete the desorption of carbon dioxide and water in the air purifier APU, thereby achieving the cyclic operation of the air purifier APU during the charging and discharging process.

[0076] Currently, coupled models of LNG-RG and LAES have emerged in existing technologies, primarily because the LNG-RG process can release a large amount of cold energy; this cold energy can be introduced into the LAES system, increasing the air liquefaction ratio under charging conditions and improving the charging and discharging efficiency of the LAES system. However, similar to the problems encountered in existing technologies for liquid air regasification, the released LNG is typically directly pressurized once to reach the target pressure for natural gas regasification conditions, and then the cold energy released during the LNG regasification process is recovered at this target pressure. The quality of the cold energy introduced by LNG-RG into the LAES system can be further improved.

[0077] Specifically, the liquid air energy storage system in the embodiment of the present invention may further include: an LNG ultra-cold charging heat exchanger XC-LUC, an LNG ultra-cold tank (such as the hot end D2-LUC, the cold end D1-LUC), an LNG ultra-cold medium, and a natural gas regasification subsystem. The natural gas regasification subsystem includes: at least two LNG cryogenic pumps (such as LCP1 and LCP2), an LNG ultra-cold heat exchanger XL-LUC, and an LNG cryogenic heat exchanger XL-DC.

[0078] In the LNG regasification condition, LNG is pressurized sequentially by at least two LNG cryogenic pumps to reach the LNG target pressure before LNG regasification; LNG is first pressurized by the first LNG cryogenic pump LCP1 and then enters the LNG ultra-cold heat exchanger XL-LUC to cool the LNG ultra-cold medium to the LNG ultra-cold temperature LUCT; the LNG ultra-cold medium at the LNG ultra-cold temperature LUCT enters the LNG ultra-cold tank to realize the storage of LNG ultra-cold energy LUCE; LNG is then pressurized by the second LNG cryogenic pump LCP2 and then passes through the LNG cryogenic heat exchanger XL-DC to cool the cryogenic medium to the cryogenic temperature DCT; the cryogenic medium at the cryogenic temperature DCT enters the cryogenic tank to realize the storage of cryogenic energy;

[0079] Among them, in order to reduce the regasification of LNG during the process of LNG super-cold energy and cryogenic energy recovery, the temperature of LNG after LNG super-cold energy recovery is lower than the liquid-gas phase transition temperature of LNG after primary pressurization; similarly, the temperature of LNG after cryogenic energy recovery is lower than the liquid-gas phase transition temperature of LNG after secondary pressurization.

[0080] Furthermore, under the LAES charging condition, before the ambient air with a cryogenic temperature reaching the charging target pressure is cooled to the air ultra-cold temperature, it first exchanges cold energy with the LNG ultra-cold medium in the LNG ultra-cold charging heat exchanger, and uses the LNG ultra-cold medium at the LNG ultra-cold temperature to cool the ambient air to the LNG ultra-cold temperature LUCT, and then exchanges cold energy with the air ultra-cold medium in the air ultra-cold charging heat exchanger, and uses the air ultra-cold medium at the air ultra-cold temperature AUCT to cool the temperature of the ambient air from the LNG ultra-cold temperature LUCT to the air ultra-cold temperature AUCT.

[0081] In this embodiment, the LNG-RG system is coupled with the LAES system, so that the sufficient cold energy generated during the LNG regasification process of the LNG-RG system can be used to improve the charging and discharging efficiency of the LAES system. In addition, for the LNG-RG system, the LNG under the LNG regasification condition of the LNG-RG system is sequentially pressurized by the first LNG cryogenic pump and the second LNG cryogenic pump to reach the LNG target pressure before LNG regasification, which also avoids the loss of high-quality cold energy caused by pressurizing the LNG to the LNG target pressure at one time, so that relatively higher quality cold energy can be obtained after the first pressurization. Applying it in the LAES system can further improve the charging and discharging efficiency of the LAES system.

[0082] In some embodiments, the natural gas regasification subsystem may further include: a third LNG cryogenic pump LCP3 located after the first LNG cryogenic pump LCP1 and the second LNG cryogenic pump LCP2, for pressurizing the LNG to a target LNG pressure; at the same time, it may also include: an LNG shallow cold heat exchanger; the LNG is first pressurized by the third LNG cryogenic pump LCP3 and then enters the LNG shallow cold heat exchanger XL-SC to cool the shallow cold medium to a shallow cold temperature SCT; the shallow cold medium at the shallow cold temperature SCT enters the shallow cold tank to realize the storage of shallow cold energy SCE.

[0083] In some embodiments, due to the coupling of the LNG-RG system, the shallow cold energy from the LNG in the shallow cold tank is surplus, and a large amount of LNG shallow cold energy can be exported for external applications.

[0084] In some embodiments, the discharge target pressure in the embodiments of the present invention is higher than the charging target pressure, which can ensure the cold energy balance between the cold energy consumption under the charging condition and the cold energy recovery under the discharging condition of the LAES system under the higher discharge target pressure; in the prior art, the charging target pressure is generally required to be higher than the discharge target pressure to achieve the cold energy balance between the charging condition and the discharging condition, especially the air super-cold energy balance.

[0085] In some embodiments, the air super-cold tank, LNG super-cold tank, and cryogenic tank in the embodiments of the present invention are respectively a pair of insulated low-pressure containers; the temperatures of the media stored in the cold end containers of the air super-cold tank, LNG super-cold tank, and cryogenic tank are respectively the air super-cold temperature, the LNG super-cold temperature, and the cryogenic temperature; the air super-cold temperature is lower than the LNG super-cold temperature, and the LNG super-cold temperature is lower than the cryogenic temperature.

[0086] In some embodiments, the air super-cold tank, LNG super-cold tank, cryogenic tank, shallow cold tank, and heat storage tank in the embodiments of the present invention can be one or more solid packed beds, including a hot end outlet and a cold end outlet; when storing cold, the cold exchange medium is exported from the hot end to the cold end for cold energy exchange, and when releasing cold, the cold exchange medium is exported from the cold end to the hot end for cold energy exchange; the heat storage and heat release processes are the same.

[0087] In some embodiments, the air super-cooled discharge heat exchanger and / or LNG super-cooled heat exchanger in the embodiments of the present invention can use a plate heat exchanger structure to meet the heat exchange between low-pressure fluids, and has the advantages of high heat exchange efficiency and small pinch point temperature difference; other heat exchangers in the embodiments of the present invention can use shell and tube heat exchangers to meet the heat exchange between high-pressure fluids.

[0088] In some embodiments, the liquid air energy storage system of the present invention may further include an LNG expander EL for generating electricity using regasified natural gas. The LNG target pressure is higher than the pressure at which the regasified natural gas enters the natural gas pipeline network, and the pressure difference between the LNG target pressure and the pipeline network pressure is used to generate power through the LNG expander EL. The LNG expander EL may also employ multi-stage expansion.

[0089] The heat exchange medium, shallow cooling medium, cryogenic medium, LNG super-cold medium, and air super-cold medium in the embodiments of the present invention are all heat exchange mediums used to distinguish different heat exchange cycles. Specifically, a stable heat exchange medium can be selected based on the corresponding heat exchange requirements and scenarios, and the present invention is not limited to this. Preferably, propane can be selected as the air super-cold medium, LNG super-cold medium, and cryogenic medium in the embodiments of the present invention, as it has the advantage of stable properties under low temperature conditions.

[0090] Generally, the exchange of cold / heat energy through a heat exchanger and a heat exchange medium will inevitably result in a loss of pinch point temperature difference. This is common knowledge in the art and is not the focus of the embodiments of the present invention. For the sake of brevity, the temperature difference loss is not described in detail every time.

[0091] On the other hand, ambient air reaching the target charging pressure will also experience a decrease in pressure after further absorbing cold energy, resulting in pressure loss through the heat exchanger. The same applies to liquid air reaching the target discharge pressure. These factors are common knowledge in the art and are not the focus of the present invention. For the sake of brevity, their impact on the target charging and discharge pressures is not detailed in each case.

[0092] It should be understood by those skilled in the art that the above differences do not affect the scope of coverage and protection content of the present invention.

[0093] In some embodiments, there is still a certain difference in the quality of the cryogenic energy recovered from the LNG regasification process and the cryogenic energy recovered from the liquid air regasification process. Directly mixing the two and storing them in a cryogenic tank will still cause some loss of high-quality cold energy. Therefore, an optimized design is also proposed in the embodiment of the present invention. Specifically, Figure 2As shown, the cryogenic tank can be divided into independent air cryogenic tanks (cold end D1-ADC, hot end D2-ADC) and LNG cryogenic tanks (cold end D1-LDC, hot end D2-LDC), and the cryogenic charging heat exchanger is divided into air cryogenic charging heat exchanger XC4-ADC and LNG cryogenic charging heat exchanger (such as XC1-LDC, XC2-LDC, XC3-LDC); the cryogenic medium is divided into air cryogenic medium and LNG cryogenic medium; the cryogenic discharge heat exchanger can be considered as an air cryogenic discharge heat exchanger; at this time, a cooling cycle with air cryogenic medium is formed between the air cryogenic tank, the air cryogenic charging heat exchanger, and the air cryogenic discharge heat exchanger, and a cooling cycle with LNG cryogenic medium is formed between the LNG cryogenic tank, the LNG cryogenic charging heat exchanger, and the LNG cryogenic heat exchanger, and the two cycles are relatively independent.

[0094] Among them, the air cryogenic charging heat exchanger is arranged at the inlet of the low-temperature compressor, and is used to cool the ambient air before entering the low-temperature compressor to the LNG cryogenic temperature through the LNG cryogenic charging heat exchanger using the LNG cryogenic medium at the LNG cryogenic temperature, so that the low-temperature compressor can perform low-temperature compression on the ambient air at the LNG cryogenic temperature; the air cryogenic charging heat exchanger is arranged at the outlet of the low-temperature compressor, and is used to cool the ambient air discharged from the low-temperature compressor to the air cryogenic temperature through the air cryogenic charging heat exchanger using the air cryogenic medium at the air cryogenic temperature; wherein, the air cryogenic temperature is lower than the LNG cryogenic temperature.

[0095] In some embodiments, an air cryogenic charging heat exchanger is used to cool ambient air that has reached the charging target pressure to an air cryogenic temperature. Furthermore, for a multi-stage cryogenic compressor unit comprised of multiple cryogenic compressors, the number of LNG cryogenic charging heat exchangers may be multiple, corresponding to the number of cryogenic compressors in the multi-stage cryogenic compressor. An LNG cryogenic charging heat exchanger is provided at the inlet of each stage of the cryogenic compressor, for utilizing sufficient LNG cryogenic energy to cryogenically compress the ambient air at the LNG cryogenic temperature. The air cryogenic charging heat exchanger is provided at the outlet of the last stage of the cryogenic compressor, for utilizing limited air cryogenic energy to cool the ambient air that has reached the charging target pressure to an air cryogenic temperature lower than the LNG cryogenic temperature, allowing the ambient air to continue to cool gradually from the air cryogenic temperature to the LNG super-cold temperature, and then to the air super-cold temperature, or directly to the air super-cold temperature from the air cryogenic temperature.

[0096] Specifically,

[0097] Under the LAES discharge condition, after the liquid air is pressurized by the second discharge cryogenic pump, the air cryogenic medium is cooled to the air cryogenic temperature through the air cryogenic discharge heat exchanger; the air cryogenic medium at the air cryogenic temperature enters the air cryogenic tank for storage;

[0098] Under LNG regasification conditions, after the LNG is pressurized by the second LNG cryogenic pump, the LNG cryogenic medium is cooled to the LNG cryogenic temperature through the LNG cryogenic heat exchanger; the LNG cryogenic medium at the LNG cryogenic temperature enters the LNG cryogenic tank for storage;

[0099] Under the LAES discharge condition, the ambient air is cooled to a cryogenic temperature by using a cryogenic medium at a cryogenic temperature through a cryogenic charging heat exchanger before and after entering the cryogenic compressor, specifically including: before the ambient air enters the cryogenic compressor, the ambient air is cooled to an LNG cryogenic temperature by using an LNG cryogenic medium at an LNG cryogenic temperature through an LNG cryogenic charging heat exchanger, and the ambient air discharged from the cryogenic compressor is cooled to an air cryogenic temperature by using an air cryogenic medium at an air cryogenic temperature through an air cryogenic charging heat exchanger.

[0100] The air cryogenic temperature in this embodiment is lower than the LNG cryogenic temperature, so the quality of air cryogenic energy is higher than that of LNG cryogenic energy. However, compared to the abundant LNG cryogenic energy, its volume is relatively limited. Therefore, how to rationally utilize air cryogenic energy and LNG cryogenic energy is the key to further improving the overall charge and discharge efficiency of the LAES. In this embodiment of the present invention, LNG cryogenic energy and air cryogenic energy are stored and released relatively independently. The abundant LNG cryogenic energy is used for pre-cooling of low-temperature compression, while the air cryogenic energy is used for cooling the ambient air to reach the target charging pressure. This comprehensive consideration of the volume and quality of LNG cryogenic energy and air cryogenic energy can further improve the overall charge and discharge efficiency of the LAES.

[0101] In some embodiments, in addition to the above embodiments, the utilization of LNG cryogenic energy and air cryogenic energy can also be determined according to system requirements, and is not limited to using LNG cryogenic energy alone to cool the ambient air before and after cryogenic compression, or using air cryogenic energy alone to cool the ambient air before and after cryogenic compression, or using air cryogenic energy first and then LNG cryogenic energy. The present invention does not limit this.

[0102] Example 1

[0103] Continue to refer to Figure 1A liquid air energy storage system includes: a normal temperature compressor C1, a heat storage charging heat exchanger XC-H, an air purifier APU, a shallow cooling charging heat exchanger XC-SC, a first deep cooling charging heat exchanger XC1-DC, a first low-temperature compressor C2, a second deep cooling charging heat exchanger XC2-DC, a second low-temperature compressor C3, a third deep cooling charging heat exchanger XC3-DC, a third low-temperature compressor C4, a fourth deep cooling charging heat exchanger XC4-DC, an LNG ultra-cooling charging heat exchanger XC-LUC, an air ultra-cooling charging heat exchanger XC-AUC, a low-temperature expander CE, a liquid-air separator LAS, and a liquid air storage tank L AD, first discharge cryopump DCP1, air super-cooled discharge heat exchanger XD-AUC, second discharge cryopump DCP2, deep-cold discharge heat exchanger XD-DC, shallow-cold discharge heat exchanger XD-SC, thermal storage discharge heat exchanger XD-H, expander E1, thermal storage tank (hot end D1-H, cold end D2-H), shallow-cold tank (hot end D1-SC, cold end D2-SC), deep-cold tank (hot end D1-DC, cold end D2-DC), LNG super-cold tank (hot end D1-LUC, cold end D2-LUC), air super-cold tank (hot end D1-AUC, cold end D2-AUC) and natural gas regasification subsystem;

[0104] The normal temperature compressor C1, heat storage charging heat exchanger XC-H, air purifier APU, shallow cooling charging heat exchanger XC-SC, first deep cooling charging heat exchanger XC1-DC, first low-temperature compressor C2, second deep cooling charging heat exchanger XC2-DC, second low-temperature compressor C3, third deep cooling charging heat exchanger XC3-DC, third low-temperature compressor C4, fourth deep cooling charging heat exchanger XC4-DC, LNG ultra-cooling charging heat exchanger XC-LUC, air ultra-cooling charging heat exchanger XC-AUC, low-temperature expander CE, liquid-air separator LAS and liquid air storage tank LAD constitute the air liquefaction path and flow direction under charging conditions;

[0105] The liquid air storage tank LAD, the first discharge cryopump DCP1, the air ultra-cooling discharge heat exchanger XD-AUC, the second discharge cryopump DCP2, the deep cooling discharge heat exchanger XD-DC, the shallow cooling discharge heat exchanger XD-SC, the heat storage discharge heat exchanger XD-H and the expander E1 constitute the liquid air regasification path and flow direction under the discharge condition.

[0106] The natural gas regasification subsystem includes: the first LNG cryogenic pump LCP1, the LNG ultra-cold heat exchanger XL-LUC, the second LNG cryogenic pump LCP2, the LNG deep-cold heat exchanger XL-DC, the third LNG cryogenic pump LCP3, the LNG shallow-cold heat exchanger XL-SC and the LNG expander EL, which constitute the natural gas regasification path and flow direction.

[0107] Among them, the air ultra-cold charging heat exchanger XC-AUC, the air ultra-cold discharge heat exchanger XD-AUC, and the air ultra-cold tank (hot end D2-AUC, cold end D1-AUC) constitute a cooling cycle using air ultra-cold medium for cold energy exchange; the LNG ultra-cold charging heat exchanger XC-LUC, the LNG ultra-cold heat exchanger XL-LUC, and the LNG ultra-cold tank (hot end D2-LUC, cold end D1-LUC) constitute a cooling cycle using LNG ultra-cold medium for cold energy exchange; the first deep-cold charging heat exchanger XC1-DC, the second deep-cold charging heat exchanger XC2-DC, the third deep-cold charging heat exchanger XC3-DC, the third deep-cold charging heat exchanger XC4-DC, the third deep-cold charging heat exchanger XC5-DC, the third deep-cold charging heat exchanger XC6-DC, the third deep-cold charging heat exchanger XC7-DC, the third deep-cold charging heat exchanger XC8-DC, the third deep-cold charging heat exchanger XC9-DC, the third deep-cold charging heat exchanger XC1-DC, the third deep-cold charging heat exchanger XC1-DC, the third deep-cold charging heat exchanger XC1-DC, the third deep-cold charging heat exchanger XC2-DC, the third deep-cold charging heat exchanger XC3 ...1-DC, the third deep-cold charging A cooling cycle for exchanging cold energy using a cryogenic medium is formed between the four cryogenic charging heat exchangers XC4-DC, the cryogenic discharge heat exchanger XD-DC, the LNG cryogenic heat exchanger XL-DC and the cryogenic tank (hot end D2-DC, cold end D1-DC); a cooling cycle for exchanging cold energy using a shallow cooling medium is formed between the shallow cooling charging heat exchanger XC-SC, the shallow cooling discharge heat exchanger XD-SC and the shallow cooling tank (hot end D2-SC, cold end D2-SC); a heat exchange cycle for exchanging heat energy using a heat exchange medium is formed between the heat storage charging heat exchanger XC-H, the heat storage discharge heat exchanger XD-H and the heat storage tank (hot end D2-H, cold end D1-H).

[0108] The air super-cold tank, LNG super-cold tank, cryogenic tank, shallow cold tank, and heat storage tank in this embodiment are respectively one or more pairs of insulated low-pressure containers, serving as the hot end and cold end of the tank body; when storing cold, the cold exchange medium is led from the hot end to the cold end for cold energy exchange, while when releasing cold, the cold exchange medium is led from the cold end to the hot end for cold energy exchange; the heat storage and release processes are similar. Specifically, the air super-cold tank includes: the air super-cold tank cold end D1-AUC and the air super-cold tank hot end D2-AUC; the LNG super-cold tank includes: the LNG super-cold tank cold end D1-LUC and the LNG super-cold tank hot end D2-LUC; the cryogenic tank includes: the cryogenic tank cold end D1-DC and the cryogenic tank hot end D2-DC; the shallow cold tank includes: the shallow cold tank cold end D1-SC and the shallow cold tank hot end D2-SC; the heat storage tank includes: the heat storage tank cold end D1-H and the heat storage tank hot end D2-H.

[0109] Under the charging condition, the ambient air liquefaction path is in operation and the liquid air regasification path is closed; the ambient air first enters the normal temperature compressor C1 along the air liquefaction path for normal temperature compression, and then uses the heat storage medium to recover the compression heat energy in the ambient air through the heat storage charging heat exchanger XC-H for storage. After outputting the compression heat energy, the ambient air continues to enter the air purifier APU to remove impurities such as carbon dioxide and water, and then is cooled to the shallow cooling temperature by the shallow cooling charging heat exchanger XC-SC by the shallow cooling medium, and then is cooled to the deep cooling temperature by the first deep cooling charging heat exchanger XC1-DC by the deep cooling medium, and then enters the first low-temperature compressor C2 at the deep cooling temperature for the first low-temperature compression and heating, and then is cooled to the deep cooling temperature by the second deep cooling charging heat exchanger XC2-DC by the deep cooling medium, and continues to enter the second low-temperature compressor C3 at the deep cooling temperature. It undergoes a second low-temperature compression and heats up, and is then cooled to a cryogenic temperature by the cryogenic medium through the third cryogenic charging heat exchanger XC3-DC. It continues to enter the third cryogenic compressor C4 at the cryogenic temperature for a third low-temperature compression to reach the charging target pressure and heat up. Finally, it is cooled to a cryogenic temperature by the cryogenic medium through the fourth cryogenic charging heat exchanger XC4-DC. It is then cooled to an LNG super-cold temperature by the LNG super-cold medium through the LNG super-cold charging heat exchanger XC-LUC. It is then cooled to an air super-cold temperature by the air super-cold medium through the air super-cold charging heat exchanger XC-AUC. It enters the cryogenic expander CE at the air super-cold temperature for low-temperature expansion, thereby obtaining a gas-liquid mixed air, and the liquid air is separated by the liquid-air separator LAS and enters the liquid air storage tank LAD for storage. The reflux air AIR UC separated from the liquid-air separator LAS can recover its cold energy in a cascade manner, and can also be used as a cold source to maintain the cryogenic environment of the system's low-temperature compression.

[0110] In the above process, the heat exchange medium enters the heat storage charging heat exchanger XC-H from the cold end D1-H of the heat storage tank to absorb the compression heat energy of the ambient air, and then enters the hot end D2-H of the heat storage tank; the shallow cold medium enters the shallow cold charging heat exchanger XC-SC from the cold end D1-SC of the shallow cold tank to cool the ambient air, and then enters the hot end D2-SC of the shallow cold tank; the deep cold heat exchange medium enters the first deep cold charging heat exchanger XC1-DC, the second deep cold charging heat exchanger XC2-DC, and the third deep cold charging heat exchanger XC3 from the cold end D1-DC of the deep cold tank. -DC and the fourth cryogenic charging heat exchanger XC4-DC cool the ambient air, and then enter the cryogenic tank hot end D2-DC; the LNG super-cold medium enters the LNG super-cold charging heat exchanger XC-LUC from the LNG super-cold tank cold end D1-LUC to cool the ambient air, and then enters the LNG super-cold tank hot end D2-LUC; the air super-cold medium enters the air super-cold charging heat exchanger XC-AUC from the air super-cold tank cold end D1-AUC to cool the ambient air, and then enters the air super-cold tank hot end D2-AUC.

[0111] During discharge operation, the air liquefaction path is closed, and the liquid air regasification path operates. Liquid air along the liquid air regasification path is first released from the liquid air storage tank LAD, then pressurized by the first discharge cryopump DCP1. The super-cold air medium is then cooled to the super-cold air temperature by the air super-cold discharge heat exchanger XD-AUC for storage, causing the liquid air to heat up. The heated liquid air is then pressurized to the discharge target pressure by the second discharge cryopump DCP2. The cryogenic medium is then cooled to the cryogenic temperature by the cryogenic discharge heat exchanger XD-DC for storage, allowing the liquid air to further heat up. The shallow-cold medium is then cooled to the shallow-cold temperature by the shallow-cold discharge heat exchanger XD-SC for storage, causing the liquid air to heat up again, producing regasified air. The regasified air then expands by absorbing the compression heat energy of the heat exchange medium in the thermal storage discharge heat exchanger XD-H, finally entering the expander E1 to generate power. The expander is a multi-stage expansion device, and its description is omitted here.

[0112] During this process, the super-cold air medium enters the super-cold air discharge heat exchanger XD-AUC from the hot end of the super-cold air tank (D2-AUC), absorbing cold energy from the liquid air before entering the super-cold air tank (D1-AUC). The cryogenic medium enters the cryogenic discharge heat exchanger XD-DC from the hot end of the cryogenic tank (D2-DC), absorbing cold energy from the liquid air before entering the cryogenic tank (D1-DC). The shallow cooling medium enters the shallow cooling discharge heat exchanger XD-SC from the hot end of the shallow cooling tank (D2-SC), absorbing cold energy from the liquid air before entering the shallow cooling tank (D1-SC). The heat exchange medium enters the thermal storage discharge heat exchanger XD-H from the hot end of the thermal storage tank (D2-H), heating the liquid air before entering the thermal storage tank (D1-H).

[0113] Under natural gas regasification conditions, the natural gas regasification path operates; liquefied natural gas along the natural gas regasification path is first pressurized by the first LNG cryogenic pump LCP1, then cooled to the LNG super-cold temperature by the LNG super-cold heat exchanger XL-LUC for storage, causing the liquefied natural gas to heat up. The heated liquefied natural gas is then pressurized by the second LNG cryogenic pump LCP2, then cooled to the cryogenic temperature by the LNG cryogenic heat exchanger XL-DC for storage, causing the liquefied natural gas to continue to heat up. The heated liquefied natural gas is further pressurized to the LNG target pressure by the third LNG cryogenic pump LCP3, then cooled to the shallow cold temperature by the LNG shallow cold heat exchanger XL-SC for storage, causing the liquefied natural gas to continue to heat up and regasify. Finally, the regasified natural gas enters the LNG expander EL to generate power, and then the regasified natural gas is exported. The LNG expander is a multi-stage expansion machine, and its description is omitted here.

[0114] During this process, the LNG super-cold medium enters the LNG super-cold heat exchanger XL-LUC from the hot end of the LNG super-cold tank (D2-LUC), absorbs cold energy from the LNG, and then enters the cold end of the LNG super-cold tank (D1-LUC). The cryogenic medium enters the LNG cryogenic heat exchanger XL-DC from the hot end of the cryogenic tank (D2-DC), absorbs cold energy from the LNG, and then enters the cryogenic tank cold end (D1-DC). The shallow cold medium enters the LNG shallow cold heat exchanger XL-SC from the hot end of the shallow cold tank (D2-SC), absorbs cold energy from the LNG, and then enters the shallow cold tank cold end (D1-SC).

[0115] Example 2

[0116] Continue to refer to Figure 2 In this embodiment, the liquid air energy storage system is based on the first embodiment, in which the cryogenic tank is divided into an LNG cryogenic tank (cold end D1-LDC, hot end D2-LDC) and an air cryogenic tank (cold end D1-ADC, hot end D2-ADC), and the cryogenic charging heat exchanger is divided into a first LNG cryogenic charging heat exchanger XC1-LDC, a second LNG cryogenic charging heat exchanger XC2-LDC, a third LNG cryogenic charging heat exchanger XC3-LDC, and an air cryogenic charging heat exchanger XC4-ADC. A cooling cycle using the LNG cryogenic medium for cold energy exchange is formed between the LNG cryogenic tank, the first LNG cryogenic charging heat exchanger XC1-LDC, the second LNG cryogenic charging heat exchanger XC2-LDC, the third LNG cryogenic charging heat exchanger XC3-LDC, and the LNG cryogenic heat exchanger; and a cooling cycle using the air cryogenic medium for cold energy exchange is formed between the air cryogenic tank, the air cryogenic charging heat exchanger, and the air cryogenic discharge heat exchanger.

[0117] Under the charging condition, the ambient air liquefaction path is in operation and the liquid air regasification path is closed; the ambient air first enters the normal temperature compressor C1 along the air liquefaction path for normal temperature compression, and then uses the heat storage medium to recover the compression heat energy in the ambient air through the heat storage charging heat exchanger XC-H for storage. After outputting the compression heat energy, the ambient air continues to enter the air purifier APU to remove impurities such as carbon dioxide and water, and then is cooled to the shallow cooling temperature by the shallow cooling charging heat exchanger XC-SC by the shallow cooling medium, and then is cooled to the LNG deep cooling temperature by the first LNG deep cooling charging heat exchanger XC1-LDC by the LNG deep cooling medium, and then enters the first low-temperature compressor C2 at the LNG deep cooling temperature for the first low-temperature compression and heating, and then is cooled to the LNG deep cooling temperature by the second LNG deep cooling charging heat exchanger XC2-LDC by the LNG deep cooling medium, and continues to enter the second low-temperature compressor C2 at the LNG deep cooling temperature. The engine C3 performs a second low-temperature compression and heats up the temperature, and is then cooled to the LNG cryogenic temperature by the LNG cryogenic medium through the third LNG cryogenic charging heat exchanger XC3-LDC. It continues to enter the third low-temperature compressor C4 at the LNG cryogenic temperature for a third low-temperature compression to reach the charging target pressure and heat up. Finally, it is cooled to the air cryogenic temperature by the air cryogenic medium through the air cryogenic charging heat exchanger XC4-ADC. It is then cooled to the LNG ultra-cold temperature by the LNG ultra-cold medium through the LNG ultra-cold charging heat exchanger XC-LUC. It is then cooled to the air ultra-cold temperature by the air ultra-cold medium through the air ultra-cold charging heat exchanger XC-AUC. It enters the low-temperature expander CE at the air ultra-cold temperature for low-temperature expansion, thereby obtaining gas-liquid mixed air, and the liquid air is separated by the liquid-air separator LAS and enters the liquid air storage tank LAD for storage. The return air AIR UC separated from the liquid-air separator LAS can recover its cold energy in a cascade manner, and can also be used as a cold source to maintain the LNG cryogenic temperature environment of the system's low-temperature compression.

[0118] Under the discharge condition, the air liquefaction path is closed and the liquid air regasification path is in operation. The liquid air is first released from the liquid air storage tank LAD along the liquid air regasification path, then pressurized by the first discharge cryopump DCP1, and then cooled to the air super-cold temperature by the air super-cold discharge heat exchanger XD-AUC for storage, so that the liquid air is heated. The heated liquid air is then pressurized to the discharge target pressure by the second discharge cryopump DCP2, and then cooled to the air super-cold temperature by the air deep-cold discharge heat exchanger XD-ADC for storage, so that the liquid air continues to heat up. The shallow-cold temperature is then cooled to the shallow-cold temperature by the shallow-cold discharge heat exchanger XD-SC for storage, so that the liquid air is heated again to produce regasified air, and then expanded by absorbing the compression heat energy of the heat exchange medium through the heat storage discharge heat exchanger XD-H, and finally enters the expander E1 to perform work and generate electricity.

[0119] Under the natural gas regasification condition, the natural gas regasification path operates; the liquefied natural gas is first pressurized by the first LNG cryogenic pump LCP1 along the natural gas regasification path, and then the LNG super-cold medium is cooled to the LNG super-cold temperature by the LNG super-cold heat exchanger XL-LUC for storage to increase the temperature of the liquefied natural gas. The heated liquefied natural gas is then pressurized by the second LNG cryogenic pump LCP2, and then the LNG cryogenic medium is cooled to the LNG cryogenic temperature by the LNG cryogenic heat exchanger XL-LDC for storage to continue to increase the temperature of the liquefied natural gas. The heated liquefied natural gas is further pressurized to the LNG target pressure by the third LNG cryogenic pump LCP3, and then the shallow-cold medium is cooled to the shallow-cold temperature by the LNG shallow-cold heat exchanger XL-SC for storage to continue to increase the temperature of the liquefied natural gas to achieve regasification. Finally, the regasified natural gas enters the LNG expander EL to generate power, and then the regasified natural gas is exported to the outside.

[0120] The transfer of the heat exchange medium in the corresponding tank during the above-mentioned charging, discharging and regasification processes is the same as the above-mentioned principle and will not be repeated here.

[0121] The embodiment of the present invention also establishes a system data model for the liquid air energy storage system of Example 2. Figure 3 The following table shows some unit nodes in the system model. The operating parameter design of the above unit nodes can be understood in conjunction with the following table:

[0122]

[0123]

[0124]

[0125] After simulation calculations using the above operating parameters in the system model, the power consumption of the main components of the system is shown in the following table. The expander is a three-stage expander group, including: a first expander E1, a second expander E2 (not shown), and a third expander E3 (not shown). The LNG expander is a two-stage expander group, including: a first LNG expander EL1 and a second LNG expander EL2 (not shown).

[0126] compressor Power (KW) expander Power (KW) cryogenic pumps Power (KW) C1 212.21 CE 12.44 DCP1 2.62 C2 60.44 E1 239.67 DCP2 30.85 C3 55.49 E2 71.09 LCP1 2.47 C4 46.78 E3 51.58 LCP2 10.66 EL1 46.37 LCP3 58.5 EL2 32.01

[0127] It can be seen from the above data that the charge and discharge efficiency of the liquid air energy storage system in the embodiment of the present invention reaches 96.78%.

[0128] The embodiment of the present invention also discloses a liquid air energy storage method, including: LAES discharge operating condition and LAES charging operating condition;

[0129] Under LAES discharge conditions, liquid air undergoes the following steps:

[0130] C1, liquid air is pressurized by the first discharge cryopump;

[0131] C2. Liquid air cools the super-cold air medium to the super-cold air temperature through the super-cold air discharge heat exchanger; wherein the super-cold air medium at the super-cold air temperature enters the super-cold air tank for storage;

[0132] C3, the liquid air is pressurized by the second discharge cryogenic pump to reach the discharge target pressure before the liquid air is regasified;

[0133] C4. Liquid air cools the cryogenic medium to a cryogenic temperature through a cryogenic discharge heat exchanger; wherein the cryogenic medium at the cryogenic temperature enters a cryogenic tank for storage;

[0134] Under LAES charging conditions, the ambient air undergoes the following steps:

[0135] D1. Ambient air is compressed by a cryogenic compressor to a target charging pressure before the ambient air is liquefied; wherein, before and after the ambient air enters the cryogenic compressor, the ambient air is cooled to a cryogenic temperature by a cryogenic charging heat exchanger using a cryogenic medium at a cryogenic temperature;

[0136] D2. The ambient air at the cryogenic temperature that reaches the target charging pressure is further cooled to the ultra-cold air temperature by using the ultra-cold air medium at the ultra-cold air temperature through the ultra-cold air charging heat exchanger;

[0137] D3: The ambient air at super-cold temperature is converted into liquid air at normal pressure through a cryogenic expander;

[0138] Among them, the cold end temperature of the air super-cold tank is the air super-cold temperature, and the cold end temperature of the cryogenic tank is the cryogenic temperature; the air super-cold temperature is lower than the cryogenic temperature.

[0139] In some embodiments, the liquid air energy storage method may further include: LNG regasification;

[0140] Under LNG regasification conditions, LNG undergoes the following steps:

[0141] L1, LNG is pressurized by the first LNG cryogenic pump;

[0142] L2, LNG is cooled to the LNG super-cold temperature by the LNG super-cold heat exchanger; wherein, the LNG super-cold medium at the LNG super-cold temperature enters the LNG super-cold tank for storage;

[0143] L3, LNG is pressurized by the second LNG cryogenic pump to reach the LNG target pressure before LNG regasification;

[0144] L4, LNG cools the cryogenic medium to a cryogenic temperature through an LNG cryogenic heat exchanger; the cryogenic medium at the cryogenic temperature enters the cryogenic tank for storage;

[0145] Wherein, under the LAES discharge condition, the D2 includes:

[0146] D2-1. First, use the LNG super-cold medium in the LNG super-cold charging heat exchanger to cool the ambient air at the cryogenic temperature that has reached the charging target pressure to the LNG super-cold temperature.

[0147] D2-2, the ambient air at the LNG super-cold temperature is further cooled to the air super-cold temperature by using the air super-cold medium at the air super-cold temperature through the air super-cold charging heat exchanger;

[0148] The LNG super-cold temperature is lower than the cryogenic temperature and higher than the air super-cold temperature.

[0149] In some embodiments, the discharge target pressure is higher than the charge target pressure.

[0150] The above-mentioned liquid air energy storage method in the embodiment of the present invention only shows the key steps concerned by the present invention. In addition to the above-mentioned steps, other process steps may also be included. For details, please refer to the relevant description in the system embodiment.

[0151] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A liquid air energy storage system, characterized in that: Includes: a cryogenic compressor, a cryogenic expander, at least two discharge cryogenic pumps, an air super-cooled discharge heat exchanger, an air super-cooled charging heat exchanger, an air super-cooled tank, an air super-cooled medium, a cryogenic discharge heat exchanger, a cryogenic charging heat exchanger, a cryogenic tank and a cryogenic medium; Among them, under LAES discharge conditions, The liquid air is pressurized sequentially by the at least two discharge cryogenic pumps to reach a discharge target pressure before the liquid air is regasified; After the liquid air is pressurized by the first discharge cryogenic pump, the air super-cold medium is cooled to an air super-cold temperature through the air super-cold discharge heat exchanger; the air super-cold medium at the air super-cold temperature enters the air super-cold tank for storage; After the liquid air is pressurized by the second discharge cryogenic pump, the cryogenic medium is cooled to a cryogenic temperature through a cryogenic discharge heat exchanger; the cryogenic medium at the cryogenic temperature enters the cryogenic tank for storage; Among them, under LAES charging conditions, The ambient air is compressed by the low-temperature compressor to the charging target pressure before the ambient air is liquefied; before and after the ambient air enters the low-temperature compressor, the ambient air is cooled to a cryogenic temperature by using a cryogenic medium at a cryogenic temperature through a cryogenic charging heat exchanger; the ambient air at the cryogenic temperature that reaches the charging target pressure is further cooled to an air super-cold temperature by using an air super-cold medium at an air super-cold temperature through an air super-cold charging heat exchanger; the ambient air at the air super-cold temperature is converted into liquid air at normal pressure by the low-temperature expander.

2. The liquid air energy storage system according to claim 1, characterized in that: Also includes: LNG super-cold charging heat exchanger, LNG super-cold tank, LNG super-cold medium and natural gas regasification subsystem; the natural gas regasification subsystem includes: at least two LNG cryogenic pumps, LNG super-cold heat exchanger and LNG cryogenic heat exchanger; Among them, under LNG regasification conditions, The LNG is pressurized sequentially by the at least two LNG cryogenic pumps to reach a target LNG pressure before LNG regasification; After the LNG is pressurized by the first LNG cryogenic pump, the LNG super-cold medium is cooled to the LNG super-cold temperature by the LNG super-cold heat exchanger; the LNG super-cold medium at the LNG super-cold temperature enters the LNG super-cold tank for storage; After the LNG is pressurized by the second LNG cryogenic pump, the cryogenic medium is cooled to a cryogenic temperature through the LNG cryogenic heat exchanger; the cryogenic medium at the cryogenic temperature enters the cryogenic tank for storage; Among them, under the LAES discharge condition, before the ambient air at the cryogenic temperature that reaches the charging target pressure is cooled to the air super-cold temperature, the ambient air is first cooled to the LNG super-cold temperature using the LNG super-cold medium at the LNG super-cold temperature through the LNG super-cold charging heat exchanger; The LNG super-cold temperature is lower than the cryogenic temperature and higher than the air super-cold temperature.

3. The liquid air energy storage system according to claim 1, characterized in that: The discharge target pressure is higher than the charge target pressure.

4. The liquid air energy storage system according to any one of claims 1-2, characterized in that: The low-temperature compressor includes a plurality of low-temperature compressors, and the deep-cold charging heat exchanger includes a plurality of deep-cold charging heat exchangers. The ambient air is compressed in multiple stages in sequence by the multiple low-temperature compressors to reach the target charging pressure, and the ambient air is cooled to a cryogenic temperature by using a cryogenic medium at a cryogenic temperature through a cryogenic charging heat exchanger before and after entering each stage of the low-temperature compressor.

5. The liquid air energy storage system according to any one of claims 1-2, characterized in that: The air super-cold tank, LNG super-cold tank and cryogenic tank are respectively a pair of insulated low-pressure containers; the temperatures of the media stored in the cold end containers of the air super-cold tank, LNG super-cold tank and cryogenic tank are respectively the air super-cold temperature, LNG super-cold temperature and cryogenic temperature; the air super-cold temperature is lower than the LNG super-cold temperature, and the LNG super-cold temperature is lower than the cryogenic temperature.

6. The liquid air energy storage system according to claim 2, characterized in that: It also includes an LNG expander, wherein the LNG target pressure is higher than the pressure of the natural gas after regasification entering the natural gas pipeline network, and the pressure difference between the LNG target pressure and the pipeline network pressure is used to generate work through the LNG expander.

7. The liquid air energy storage system according to any one of claims 1-2, characterized in that: The air super-cooled discharge heat exchanger and / or the LNG super-cooled heat exchanger is a plate heat exchanger structure.

8. The liquid air energy storage system according to claim 2, characterized in that: The number of the LNG cryogenic pumps is 3.

9. The liquid air energy storage system according to claim 2, characterized in that: The cryogenic charging heat exchanger includes: an LNG cryogenic charging heat exchanger located at the inlet of the cryogenic compressor, and an air cryogenic charging heat exchanger located at the outlet of the cryogenic compressor; the cryogenic tank includes: an air cryogenic tank and an LNG cryogenic tank that are independent of each other; the cryogenic discharge heat exchanger is an air cryogenic discharge heat exchanger; the cryogenic medium includes: air cryogenic medium and LNG cryogenic medium; Among them, under LAES discharge conditions, After the liquid air is pressurized by the second discharge cryogenic pump, the air cryogenic medium is cooled to an air cryogenic temperature through an air cryogenic discharge heat exchanger; the air cryogenic medium at the air cryogenic temperature enters the air cryogenic tank for storage; Among them, under LNG regasification conditions, After the LNG is pressurized by the second LNG cryogenic pump, the LNG cryogenic medium is cooled to the LNG cryogenic temperature through the LNG cryogenic heat exchanger; the LNG cryogenic medium at the LNG cryogenic temperature enters the LNG cryogenic tank for storage; wherein the air cryogenic temperature is lower than the LNG cryogenic temperature; Wherein, under the LAES discharge condition, the ambient air is cooled to a cryogenic temperature by using a cryogenic medium at a cryogenic temperature through a cryogenic charging heat exchanger before and after the ambient air enters the cryogenic compressor, specifically including: Before and after the ambient air enters the cryogenic compressor, the ambient air is cooled to the LNG cryogenic temperature by using the LNG cryogenic medium at the LNG cryogenic temperature through the LNG cryogenic charging heat exchanger and / or is cooled to the air cryogenic temperature by using the air cryogenic medium at the air cryogenic temperature through the air cryogenic charging heat exchanger.

10. A liquid air energy storage method, characterized in that: include: LAES discharge condition and LAES charging condition; Under LAES discharge conditions, liquid air undergoes the following steps: C1, liquid air is pressurized by the first discharge cryopump; C2. Liquid air cools the super-cold air medium to the super-cold air temperature through the super-cold air discharge heat exchanger; wherein the super-cold air medium at the super-cold air temperature enters the super-cold air tank for storage; C3, the liquid air is pressurized by the second discharge cryogenic pump to reach the discharge target pressure before the liquid air is regasified; C4. Liquid air cools the cryogenic medium to a cryogenic temperature through a cryogenic discharge heat exchanger; wherein the cryogenic medium at the cryogenic temperature enters a cryogenic tank for storage; Under LAES charging conditions, the ambient air undergoes the following steps: D1. Ambient air is compressed by a cryogenic compressor to a target charging pressure before the ambient air is liquefied; wherein, before and after the ambient air enters the cryogenic compressor, the ambient air is cooled to a cryogenic temperature by a cryogenic charging heat exchanger using a cryogenic medium at a cryogenic temperature; D2. The ambient air at the cryogenic temperature that reaches the target charging pressure is further cooled to the ultra-cold air temperature by using the ultra-cold air medium at the ultra-cold air temperature through the ultra-cold air charging heat exchanger; D3: The ambient air at super-cold temperature is converted into liquid air at normal pressure through a cryogenic expander; Among them, the cold end temperature of the air super-cold tank is the air super-cold temperature, and the cold end temperature of the cryogenic tank is the cryogenic temperature; the air super-cold temperature is lower than the cryogenic temperature.

11. The liquid air energy storage method according to claim 10, characterized in that: Also includes: LNG regasification conditions; Under LNG regasification conditions, LNG undergoes the following steps: L1, LNG is pressurized by the first LNG cryogenic pump; L2, LNG is cooled to the LNG super-cold temperature by the LNG super-cold heat exchanger; wherein, the LNG super-cold medium at the LNG super-cold temperature enters the LNG super-cold tank for storage; L3, LNG is pressurized by the second LNG cryogenic pump to reach the LNG target pressure before LNG regasification; L4, LNG cools the cryogenic medium to a cryogenic temperature through an LNG cryogenic heat exchanger; the cryogenic medium at the cryogenic temperature enters the cryogenic tank for storage; Wherein, under the LAES discharge condition, the D2 includes: D2-1. First, use the LNG super-cold medium in the LNG super-cold charging heat exchanger to cool the ambient air at the cryogenic temperature that has reached the charging target pressure to the LNG super-cold temperature. D2-2, the ambient air at the LNG super-cold temperature is further cooled to the air super-cold temperature by using the air super-cold medium at the air super-cold temperature through the air super-cold charging heat exchanger; The LNG super-cold temperature is lower than the cryogenic temperature and higher than the air super-cold temperature.

12. The liquid air energy storage method according to claim 10, characterized in that: The discharge target pressure is higher than the charge target pressure.

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