Coupling method and system for liquefied natural gas re-gasification and liquid air energy storage

Abstract

A coupling method and system for liquefied natural gas re-gasification (LNG-RG) and liquid air energy storage (LAES). The coupling method comprises: when an LNG-RG system operates and an LAES system is in a charging mode, jointly outputting, to a primary gas in the charging mode of the LAES system, cold energy generated by the LNG-RG system and cold energy stored in the LAES system; when the LNG-RG system operates and the LAES system is in a standby mode, outputting, to the LAES system for storage, cold energy generated by the LNG-RG system; and when the LNG-RG system operates and the LAES system is in a discharging mode, jointly outputting, to the LAES system for storage, cold energy generated by the LNG-RG system and cold energy generated in the discharging mode of the LAES system. In the method and system, regardless of whether an LAES system is in any of a charging mode, a standby mode or a discharging mode, effective coupling utilization of cold energy and heat energy between the LAES system and an LNG-RG system can be realized, the coupling system is perfected, and the output requirements for the LNG-RG system and the LAES system in multiple modes are met.

Description

Coupling method and system of liquefied natural gas regasification and liquid air energy storage

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. CN202410401275.X filed on April 3, 2024. The full text of the above-mentioned Chinese patent application is hereby cited as part of this application. Technical Field

[0003] The present invention belongs to the technical field of large-scale energy storage, and in particular relates to a coupling method and system for liquefied natural gas regasification and liquid air energy storage. Background Art

[0004] 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 from the tank and pressurized and heated, and then enters the expander to generate work and generate electricity, realizing valley electricity peak utilization. It can play an important role in peak regulation of the power grid, but there will be a loss of cold energy during the charging and discharging process. In order to replenish the lost cold energy, additional electricity is usually required to supplement the cold energy, which is costly.

[0005] In recent years, the proportion of natural gas in energy consumption has steadily increased as a clean energy source. With improvements in natural gas liquefaction technology and reductions in LNG (Liquefied Natural Gas) transportation costs, LNG has gained widespread application and attention. LNG receiving terminals often involve the LNG regasification (RG) process. The regasification of LNG into natural gas releases a significant amount of cold energy, making the coupled application of LAES and LNG-RG systems highly practical and promising.

[0006] At present, scholars and manufacturers at home and abroad have proposed multiple coupling models for the LAES system and the LNG-RG system. However, they have not considered the coupled continuous operation of the LNG-RG system and the LAES system under various working conditions. The coupling system is imperfect, and the effective coupling utilization rate of the cold and heat energy between the systems is low. Summary of the Invention

[0007] In view of this, an object of the present invention is to propose a coupling method for LNG-RG and LAES to solve the problems in the prior art such as the imperfect coupling system between the LAES system and the LNG-RG system, the low effective coupling utilization rate of the cold energy and heat energy between the systems, and the inability to adapt to the output requirements of the LNG-RG system and the LAES system under multiple working conditions.

[0008] In some illustrative embodiments, the coupling method of LNG-RG and LAES includes: when the LNG-RG system is operating and the LAES system is in a charging state, outputting the cold energy generated by the LNG-RG system and the cold energy stored by the LAES system to the main gas in the charging state of the LAES system, thereby achieving regasification of LNG and liquefaction of the main gas; when the LNG-RG system is operating and the LAES system is in a stationary state, outputting the cold energy generated by the LNG-RG system to the LAES system for storage, thereby achieving regasification of LNG and cold storage of the LAES system; when the LNG-RG system is operating and the LAES system is in a discharging state, outputting the cold energy generated by the LNG-RG system and the cold energy generated by the LAES system in the discharging state to the LAES system for storage, thereby achieving regasification of LNG, regasification of liquefied main gas, and cold storage of the LAES system.

[0009] In some optional embodiments, the coupling method further includes: when the LNG-RG system is operating and the LAES system is shut down or has excess cold storage, outputting the cold energy generated by the LNG-RG system to the ambient air, bypassing the LAES system, to achieve regasification of LNG.

[0010] In some optional embodiments, the coupling method further includes: when the LNG-RG system is shut down, cutting off the cold energy exchange between the LNG-RG system and the LAES system.

[0011] In some optional embodiments, natural gas in the regasification process of the LNG-RG system is used as a cold energy carrier to directly exchange cold energy in the LAES system; or, other heat exchange media are used as a cold energy carrier to indirectly exchange cold energy with the LAES system.

[0012] In some optional embodiments, cold energy is divided into deep cold energy and shallow cold energy according to quality.

[0013] In some optional embodiments, when the LNG-RG system is running and the LAES system is in a charging condition, the cold energy generated by the LNG-RG system and the cold energy stored in the LAES system are jointly output to the main gas under the charging condition of the LAES system, thereby realizing the process of regasification of LNG and liquefaction of the main gas, including: outputting the shallow cold energy of the LNG-RG system and the LAES system, as well as the deep cold energy of the LNG-RG system and the LAES system, to the main gas in sequence along the flow direction of the main gas under the charging condition.

[0014] In some optional embodiments, when the LNG-RG system is running and the LAES system is in a static condition, the cold energy generated by the LNG-RG system is output to the LAES system for storage, thereby realizing the process of LNG regasification and cold storage of the LAES system, including: outputting the deep cold energy and shallow cold energy of the LNG-RG system to the LAES system for independent storage.

[0015] In some optional embodiments, when the LNG-RG system is running and the LAES system is in a discharge condition, the cold energy generated by the LNG-RG system and the cold energy generated by the LAES system under the discharge condition are jointly output to the LAES system for storage, thereby realizing the regasification of LNG, the regasification of liquefied main gas and the cold storage process of the LAES system, including: outputting the shallow cold energy of the LNG-RG system and the LAES system under the discharge condition, and the deep cold energy of the LNG-RG system and the LAES system under the discharge condition to the LAES system for independent storage.

[0016] In some optional embodiments, the LAES system includes: a shallow cold tank for storing and releasing shallow cold energy, and a cryogenic tank for storing and releasing deep cold energy; wherein, the hot end temperature of the shallow cold tank is between the ambient temperature and zero degrees Celsius but not lower than zero degrees Celsius, and its cold end temperature is the shallow cold temperature; the hot end temperature of the cryogenic tank is the shallow cold temperature, and its cold end temperature is the liquid-gas phase transition temperature during LNG regasification.

[0017] In some optional embodiments, the process of outputting the shallow cooling energy of the LNG-RG system and the LAES system, and the deep cooling energy of the LNG-RG system and the LAES system to the main gas in sequence along the flow direction of the main gas under the charging condition includes: outputting the shallow cooling energy of the LNG-RG system and the LAES system together to the main gas in the LAES system that has undergone air purification but has not undergone one or more stages of compression, and the main gas that has undergone one or more stages of compression but has not absorbed the deep cooling energy; outputting the deep cooling energy of the LNG-RG system and the LAES system together to the main gas in the LAES system that has absorbed the shallow cooling energy but has not been expanded and liquefied.

[0018] In some optional embodiments, the coupling method further includes: when the LAES system is in a charging condition, outputting the super-cold energy of the reflux main gas generated under the charging condition of the LAES system to the main gas that has absorbed the cryogenic energy but has not been expanded and liquefied; wherein the quality of the super-cold energy is higher than that of the cryogenic energy.

[0019] In some optional embodiments, the deep cold energy and shallow cold energy generated by the LAES system under discharge conditions are sequentially obtained from the regasified main gas during the process of temperature increase and expansion of the liquefied main gas.

[0020] Another object of the present invention is to provide a coupling system of LNG-RG and LAES to solve the problems existing in the prior art.

[0021] In some illustrative embodiments, the LNG-RG and LAES coupling system includes: a dynamic monitoring module for monitoring the current status of the LNG-RG system and the LAES system; a first coupling control module for, when the LNG-RG system is operating and the LAES system is in a charging state, outputting the cold energy generated by the LNG-RG system and the cold energy stored by the LAES system to the main gas in the LAES system charging state, thereby achieving LNG regasification and main gas liquefaction; a second coupling control module for, when the LNG-RG system is operating and the LAES system is in a static state, outputting the cold energy generated by the LNG-RG system to the LAES system for storage, thereby achieving LNG regasification and cold storage in the LAES system; and a third coupling control module for, when the LNG-RG system is operating and the LAES system is in a discharging state, outputting the cold energy generated by the LNG-RG system and the cold energy generated by the LAES system in a discharging state to the LAES system for storage, thereby achieving LNG regasification, regasification of liquefied main gas, and cold storage in the LAES system.

[0022] In some optional embodiments, the coupling system further includes: a fourth coupling control module, which is used to output the cold energy generated by the LNG-RG system to the ambient air bypassing the LAES system when the LNG-RG system is running and the LAES system is shut down or has excess cold storage, thereby achieving regasification of LNG.

[0023] In some optional embodiments, the coupling system further includes: a fifth coupling control module, configured to cut off the cold energy exchange between the LNG-RG system and the LAES system when the LNG-RG system is shut down.

[0024] In some optional embodiments, the coupling system further includes: a cold storage tank for storing cold energy of the LNG-RG system and the LAES system, and the main gas liquefaction path and the liquid main gas regasification path of the LAES system are arranged outside the cold storage tank.

[0025] In some optional embodiments, the coupling system further includes: a cold storage tank for storing cold energy of the LNG-RG system and the LAES system, the main gas liquefaction path and the liquid main gas regasification path of the LAES system pass through the cold storage tank, and directly exchange cold energy with the cold storage medium in the cold storage tank; in the cold storage tank, the main gas liquefaction path and the liquid main gas regasification path are the same path but the airflow directions are opposite.

[0026] In some optional embodiments, natural gas on the LNG-RG system liquefied natural gas regasification path is used as a cold energy carrier to directly exchange cold energy in the LAES system; or, other heat exchange media are used as a cold energy carrier to indirectly exchange cold energy with the LAES system.

[0027] In some optional embodiments, cold energy is divided into deep cold energy and shallow cold energy according to quality.

[0028] In some optional embodiments, the first coupling control module is used to output the shallow cooling energy of the LNG-RG system and the LAES system, and the deep cooling energy of the LNG-RG system and the LAES system, to the main gas in sequence along the flow direction of the main gas under charging conditions.

[0029] In some optional embodiments, the second coupling control module is used to output the deep cold energy and shallow cold energy of the LNG-RG system to the LAES system for independent storage.

[0030] In some optional embodiments, the third coupling control module is used to output the shallow cooling energy under the discharge conditions of the LNG-RG system and the LAES system, and the deep cooling energy under the discharge conditions of the LNG-RG system and the LAES system, to the LAES system for independent storage.

[0031] In some optional embodiments, the LAES system includes: a shallow cold tank for storing and releasing shallow cold energy, and a cryogenic tank for storing and releasing deep cold energy; wherein, the hot end temperature of the shallow cold tank is between the ambient temperature and zero degrees Celsius but not lower than zero degrees Celsius, and its cold end temperature is the shallow cold temperature; the hot end temperature of the cryogenic tank is the shallow cold temperature, and its cold end temperature is the liquid-gas phase transition temperature during LNG regasification.

[0032] In some optional embodiments, the first coupling module is used to jointly output the shallow cold energy of the LNG-RG system and the LAES system to the main gas in the LAES system that has undergone air purification but has not undergone one or more stages of compression, and the main gas that has undergone one or more stages of compression but has not absorbed deep cold energy; and to jointly output the deep cold energy of the LNG-RG system and the LAES system to the main gas in the LAES system that has absorbed the shallow cold energy but has not been expanded and liquefied.

[0033] In some optional embodiments, the first coupling module is further used to output the super-cold energy of the reflux main gas generated under the charging condition of the LAES system to the main gas that has absorbed the cryogenic energy but has not been expanded and liquefied when the LAES system is in the charging condition; wherein the quality of the super-cold energy is higher than that of the cryogenic energy.

[0034] In some optional embodiments, the deep cold energy and shallow cold energy generated by the LAES system under discharge conditions are sequentially obtained from the regasified main gas during the process of temperature increase and expansion of the liquefied main gas.

[0035] Compared with the existing technology, this application has the following advantages:

[0036] In this embodiment of the present invention, the LNG-RG system's operating conditions are not only coupled with the LAES system's charging conditions, but also with the LAES system's static and discharging conditions. This allows for effective coupling and utilization of cooling and thermal energy between the LNG-RG system and the LAES system, regardless of whether the LAES system is in any of the charging, static, or discharging conditions. This improves the coupled system and enables the output requirements of both the LNG-RG and LAES systems to be met under multiple operating conditions. Furthermore, while the LNG-RG system maintains continuous operation coupled with the LAES system under various operating conditions, the LAES system can switch operating conditions based on its actual needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG1 is a first example of a principle block diagram of an LNG-RG system and a LAES system according to an embodiment of the present invention;

[0038] FIG2 is an example of a first coupling operating condition of the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0039] FIG3 is an example of a second coupling operating condition of the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0040] FIG4 is an example 1 of the third coupling operating condition of the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0041] FIG5 is an example 1 of the fourth coupling operating condition of the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0042] FIG6 is an example 1 of the fifth coupling operating condition of the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0043] FIG7 is a second example of a principle block diagram of an LNG-RG system and a LAES system according to an embodiment of the present invention;

[0044] FIG8 is a second example of the first coupling operating condition of the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0045] FIG9 is a second example of a second coupling operating condition between the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0046] FIG10 is a second example of the third coupling operating condition between the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0047] FIG11 is a third example of the first coupling operating condition of the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0048] FIG12 is a second example of the fourth coupling operating condition between the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0049] FIG13 is a structural example 1 of a coupling system between an LNG-RG system and a LAES system according to an embodiment of the present invention;

[0050] FIG14 is a fourth example of the first coupling operating condition of the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0051] FIG15 is a third example of the second coupling operating condition between the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0052] FIG16 is a third example of the third coupling operating condition between the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0053] FIG17 is a third example of the fourth coupling operating condition between the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0054] FIG18 is a second structural example of a coupling system between an LNG-RG system and a LAES system according to an embodiment of the present invention;

[0055] FIG19 is a third structural example of a coupling system between an LNG-RG system and a LAES system according to an embodiment of the present invention;

[0056] FIG20 is a fifth example of the first coupling operating condition of the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0057] FIG21 is a fourth example of the second coupling operating condition between the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0058] FIG22 is a fourth example of the third coupling operating condition between the LNG-RG system and the LAES system according to an embodiment of the present invention;

[0059] FIG23 is a fourth structural example of a coupling system between an LNG-RG system and a LAES system according to an embodiment of the present invention;

[0060] FIG24 is an example of a system block diagram of a coupled system of an LNG-RG system and a LAES system according to an embodiment of the present invention.

[0061] Reference numerals:

[0062] Natural gas heat exchanger HX-NG (Heat Exchanger-Natural Gas), deep-cooled natural gas heat exchanger HX-NG1 (Heat Exchanger-Natural Gas 1), shallow-cooled natural gas heat exchanger HX-NG2 (Heat Exchanger-Natural Gas 2);

[0063] HX-SC1 (Heat Exchanger-Shallow Cold 1), HX-SC2 (Heat Exchanger-Shallow Cold 2), HX-CB (Heat Exchanger-Cold Box), HX-UC (Heat Exchanger-Ultra Cold)

[0064] Shallow Cold Dewar (SCD), first shallow cold tank SCD1 (Shallow Cold Dewar 1), second shallow cold tank SCD2 (Shallow Cold Dewar 2), deep cold tank DCD (Deep Cold Dewar), first deep cold tank DCD1 (Deep Cold Dewar 1), second deep cold tank DCD2 (Deep Cold Dewar 2);

[0065] Discharge heat exchanger HX-DC (Heat Exchanger-Discharge), deep cooling discharge heat exchanger HX-DC1 (Heat Exchanger-Discharge 1), shallow cooling discharge heat exchanger HX-DC2 (Heat Exchanger-Discharge 2);

[0066] Compressor C (Compressor), Cryogenic Expander CE (Cryogenic Expander), Liquid Air Separator LAS (Liquid Air Separator), Liquid Air Dewar LAD (Liquid Air Dewar), Cryogenic Pump CP (Cryogenic Pump), Expander E (Expander), First Expander E1 (Expander 1), Second Expander E2 (Expander 2). DETAILED DESCRIPTION

[0067] 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.

[0068] It should be noted that the various technical features in the embodiments of the present invention can be combined with each other without conflict.

[0069] Terminology Notes:

[0070] LNG-RG system, liquefied natural gas regasification system, is used to realize the conversion of liquefied natural gas (LNG) into natural gas (NG). It has a liquefied natural gas regasification path. LNG is converted into NG in the process of releasing cold energy (and absorbing heat energy) on the liquefied natural gas regasification path.

[0071] The LAES system, a liquid air energy storage system, is used to convert main gas (air) into liquefied main gas (liquid air) for energy storage through electric energy during the charging process, and to generate electric energy in the process of converting liquefied main gas into regasified main gas during the discharge process. It has a main gas liquefaction path and a liquefied main gas regasification path. The main gas is converted into liquefied main gas in the process of absorbing cold energy (and releasing heat energy at the same time) on the main gas liquefaction path, and the liquefied main gas is converted into regasified main gas in the process of releasing cold energy (and absorbing heat energy) on the air regasification path.

[0072] Under the charging condition of the LAES system, the main gas refers to the part of air that is purified, passes through the main gas liquefaction path, and finally becomes liquid air, excluding the return air that needs to recover cold energy; under the discharging condition of the LAES system, the liquefied main gas refers to liquid air and regasified liquid air.

[0073] In an embodiment of the present invention, a coupling method of LNG-RG and LAES is disclosed. Specifically, as shown in FIG1 , FIG1 is an example 1 of a principle block diagram of LNG-RG and LAES in an embodiment of the present invention. The coupling method involves multiple coupling conditions between the LNG-RG system and the LAES system, including: a first coupling condition in which the LNG-RG system is running and the LAES is in a charging condition, a second coupling condition in which the LNG-RG system is running and the LAES is in a stationary condition, and a third coupling condition in which the LNG-RG system is running and the LAES is in a discharging condition.

[0074] As shown in FIG2 , FIG2 is an example 1 of a first coupling operating condition of the LNG-RG system and the LAES system according to an embodiment of the present invention, and the coupling operating condition is based on the principle block diagram example 1 shown in FIG1 ;

[0075] First coupling condition: When the LNG-RG system is running and the LAES system is in the charging condition, the cold energy generated by the LNG-RG system and the cold energy stored in the LAES system are jointly output to the main gas under the charging condition of the LAES system, realizing the regasification of LNG and the liquefaction of the main gas.

[0076] Among them, from the LAES system side, the main gas under the charging condition absorbs the cold energy generated in the LNG regasification process during the operation of the LNG-RG system and the cold energy stored in the LAES system's own cold storage equipment (such as the cold storage tank), thereby realizing the cooling of the main gas; and from the LNG-RG system side, the LNG of the LNG-RG system absorbs the heat energy from the main gas under the charging condition of the LAES system to realize the regasification of LNG; that is, the effective coupling utilization of the cold energy of the LNG regasification of the LNG-RG system, the cold energy stored in the LAES system itself and the heat energy of the main gas under the charging condition of the LAES system is realized.

[0077] As shown in FIG3 , FIG3 is an example 1 of a second coupling operating condition of the LNG-RG system and the LAES system according to an embodiment of the present invention, and the coupling operating condition is based on the principle block diagram example 1 shown in FIG1 ;

[0078] The second coupling condition: When the LNG-RG system is running and the LAES system is in a static condition, the cold energy generated by the LNG-RG system is output to the LAES system for storage, realizing the regasification of LNG and the cold storage of the LAES system.

[0079] From the LAES system's perspective, when the system is in a static state, only its own cold storage equipment participates in the cold energy exchange with the LNG-RG system. During this process, the cold energy stored in the LAES system is increased by absorbing the cold energy regasified from the LNG in the LNG-RG system. From the LNG-RG system's perspective, the LNG in the LNG-RG system absorbs heat energy from the cold storage equipment in the LAES system to achieve LNG regasification. This effectively couples the cold energy regasified from the LNG-RG system with the heat energy from the cold storage equipment in the LAES system.

[0080] The static operating condition of the LAES system in the embodiment of the present invention includes the static operating condition after the LAES system is charged and the static operating condition after the LAES system is discharged.

[0081] As shown in FIG4 , FIG4 is a third coupling operating condition example 1 of the LNG-RG system and the LAES system in an embodiment of the present invention, and the coupling operating condition is based on the principle block diagram example 1 shown in FIG1 ;

[0082] The third coupling condition: when the LNG-RG system is operating and the LAES system is in the discharge condition, the cold energy generated by the LNG-RG system and the cold energy generated by the LAES system in the discharge condition are output to the LAES system for storage, thereby realizing the regasification of LNG, the regasification of liquefied main gas and the cold storage of the LAES system.

[0083] Among them, from the LAES system side, the LAES system's own cold storage equipment simultaneously absorbs the cold energy generated during the regasification process of the liquefied main gas under the LAES system's discharge condition and the cold energy generated by the LNG regasification of the LNG-RG system, thereby increasing its own stored cold energy. The liquefied main gas absorbs heat energy from the LAES system's cold storage equipment to achieve regasification of the liquefied main gas / heating of the regasified main gas; from the LNG-RG system side, the LNG-RG system also absorbs heat energy from the LAES system's cold storage equipment during the process to achieve LNG regasification, that is, it realizes the effective coupling utilization of the cold energy of the LNG regasification of the LNG-RG system, the cold energy of the liquefied main gas regasification under the LAES system's discharge condition, and the heat energy of the LAES system's own cold storage equipment.

[0084] Based on the first coupling condition, the second coupling condition, and the third coupling condition, it can be achieved that when the LNG-RG system is in operation, no matter whether the LAES system is in the charging condition, the static condition, the discharging condition, or even when the operating condition changes, the LNG-RG system can continuously produce regasified natural gas, which is particularly consistent with the actual state of continuous production of the LNG-RG system and periodic operation of the LAES system.

[0085] In this embodiment of the present invention, the LNG-RG system's operating conditions are not only coupled with the LAES system's charging conditions, but also with the LAES system's static and discharging conditions. This allows for effective coupling and utilization of cooling and thermal energy between the LNG-RG system and the LAES system, regardless of whether the LAES system is in any of the charging, static, or discharging conditions. This improves the coupled system and enables the output requirements of both the LNG-RG and LAES systems to be met under multiple operating conditions. Furthermore, while the LNG-RG system maintains continuous operation coupled with the LAES system under various operating conditions, the LAES system can switch operating conditions based on its actual needs.

[0086] In some embodiments, the coupling method of liquefied natural gas regasification and liquid air energy storage in the embodiment of the present invention may further include: a fourth coupling operating condition when the LNG-RG system is running and the LAES system is shut down or has excess cold storage.

[0087] As shown in FIG5 , FIG5 is a fourth coupling operating condition example 1 of the LNG-RG system and the LAES system in an embodiment of the present invention, and the coupling operating condition is based on the principle block diagram example 1 shown in FIG1 ;

[0088] The fourth coupling condition: When the LNG-RG system is in operation and the LAES system is out of service or has excess cold storage, the cold energy generated by the LNG-RG system is output to the ambient air, bypassing the LAES system, to achieve LNG regasification.

[0089] In this embodiment, the LAES system may be shut down during maintenance, during which time the system's primary equipment is unavailable and unable to provide heat to the LNG-RG system. Excessive LAES system cold storage may occur during periods of inactivity, when the system's cold storage equipment has already absorbed maximum cold energy and cannot absorb any more from the LNG-RG system. Therefore, the LNG-RG system requires an additional heat source.

[0090] In this embodiment, the operating conditions of the LNG-RG system are coupled with the conditions of the LAES system being shut down and having excess cold storage. This ensures that the LNG-RG system can maintain continuous operation by directly providing a heat source for the LNG-RG system by introducing purified ambient air from the outside when the LAES system is shut down or has excess cold storage. This also prevents the LNG-RG system from continuing to exchange cold energy with the LAES system when the LAES system has excess cold storage, resulting in insufficient cold energy release from the LNG, reduced regasification efficiency, and, in turn, reduced production or excessively low temperature of the regasified natural gas.

[0091] Specifically, in certain circumstances in the embodiment of the present invention, outputting the cold energy generated during the operation of the LNG-RG system to the ambient air bypassing the LAES system means outputting the cold energy generated during the operation of the LNG-RG system to the ambient air bypassing the main gas liquefaction path and the liquefied main gas regasification path of the LAES system.

[0092] In one embodiment of the present invention, a gas-phase pathway independent of the LAES system can be established for the LNG-RG system. Under specific circumstances, purified ambient air can be introduced and exchanged with LNG for cold energy, allowing the LNG to directly absorb heat energy from the ambient air and achieve LNG regasification. This gas-phase pathway can also utilize portions of the LAES system's pipelines that do not pass through the system's main equipment (e.g., the compressor, cryogenic expander, gas-liquid separator, liquid air storage tank, expander, and cold storage tank). This avoids interruptions during maintenance or outages of the LAES system's main equipment and eliminates the need for cold energy exchange with the LAES system, ensuring the normal operation of LNG regasification.

[0093] In some embodiments, the coupling method of liquefied natural gas regasification and liquid air energy storage in the embodiments of the present invention further includes: a fifth coupling operating condition when the LNG-RG system is shut down and the LAES system is operating (charging, standing, discharging).

[0094] As shown in FIG6 , FIG6 is a fifth coupling operating condition example 1 of the LNG-RG system and the LAES system according to an embodiment of the present invention, and the coupling operating condition is based on the principle block diagram example 1 shown in FIG1 ;

[0095] The fifth coupling condition: when the LNG-RG system is shut down, the cold energy exchange between the LNG-RG system and the LAES system is cut off.

[0096] When the LNG-RG system is in a shutdown condition, since the LNG-RG system is not regasifying LNG, there is no need to absorb heat energy from outside it (the LNG-RG system). By cutting off the cold energy exchange between the two systems, the two systems are decoupled, allowing the LAES system to operate independently with its original system architecture. That is, it uses its own cold storage equipment to complete the liquefaction of the main gas under charging conditions and the regasification of the liquefied main gas under discharging conditions.

[0097] The first to fifth coupling operating conditions in the embodiment of the present invention involve the operating condition coupling between the LNG-RG system and the LAES system, ensuring that the LNG-RG system and the LAES system can meet production requirements individually or in combination.

[0098] In some embodiments, the cold energy involved between the two systems is divided into deep cold energy and shallow cold energy based on the quality of the cold energy, with deep cold energy being of higher quality than shallow cold energy. By dividing the cold energy into deep cold energy and shallow cold energy, the cold energy exchange between the two systems is further divided into shallow cold energy exchange and deep cold energy exchange.

[0099] As shown in FIG7 , FIG7 is a second example of a principle block diagram of LNG-RG and LAES in an embodiment of the present invention, which divides the cold energy involved into deep cold energy and shallow cold energy based on the principle block diagram example 1 of FIG1 . Specifically,

[0100] As shown in FIG8 , FIG8 is a first coupling operating condition example 2 of the LNG-RG system and the LAES system according to an embodiment of the present invention, and the coupling operating condition is based on the principle block diagram example 2 shown in FIG7 ;

[0101] For the first coupling working condition, the shallow cold energy generated by the LNG-RG system and stored by the LAES system, as well as the deep cold energy generated by the LNG-RG system and stored by the LAES system, can be output to the main gas in sequence along the flow direction of the main gas of the LAES system under the charging condition.

[0102] Furthermore, under the first coupling operating condition, the shallow cold energy generated by the LNG-RG system and stored in the LAES system can be jointly output to the main gas in the LAES system that has undergone air purification but has not undergone one or more stages of compression, and the main gas that has undergone one or more stages of compression but has not absorbed deep cold energy; and the deep cold energy generated by the LNG-RG system and stored in the LAES system can be jointly output to the main gas in the LAES system that has absorbed shallow cold energy but has not been expanded and liquefied.

[0103] By exporting shallow cooling energy to the main gas that has undergone air purification but has not yet undergone one or more stages of compression, the LNG-RG system's shallow cooling energy can be fully utilized to first cool the main gas before it is compressed by the LAES system. This allows for low-temperature compression of the main gas during the subsequent compression process, reducing the LAES system's electricity costs under charging conditions. Furthermore, air purification of the main gas before cooling removes dust, water, and carbon dioxide from the incoming ambient air, preventing condensation and crystallization of water and carbon dioxide after cooling, which can cause pipeline blockage and damage.

[0104] The LAES system in the existing technology usually configures a heat storage tank to recover and store the compression heat energy of the main gas compressed by the compressor unit, and uses it to heat and expand the regasified main gas under the discharge condition of the LAES system. However, the actual value of this compression heat energy is low, and the heat storage and maintenance costs are high. It can be replaced by heat energy provided by an external heat source.

[0105] The shallow cold energy is directly exchanged with the main gas that has been compressed in one or more stages but has not absorbed deep cold energy. That is, the shallow cold energy is directly exchanged with the main gas with compression heat energy, making full use of the shallow cold energy of LNG-RG to reduce the power consumption of main gas compression, thereby improving the charging efficiency of the LAES system.

[0106] Preferably, when a compressor unit is used to perform multi-stage compression on the main gas, shallow cold energy can be used to exchange cold energy after each stage of the compressor.

[0107] As shown in FIG9 , FIG9 is a second coupling operating condition example 2 of the LNG-RG system and the LAES system according to an embodiment of the present invention, and the coupling operating condition is based on the principle block diagram example 2 shown in FIG7 ;

[0108] For the second coupling condition, the shallow cooling energy and deep cooling energy of the LNG-RG system can be output to the LAES system for independent storage;

[0109] In this embodiment, one cold storage device of the LAES system stores shallow cold energy independently, and another cold storage device stores deep cold energy independently.

[0110] As shown in FIG10 , FIG10 is a third coupling operating condition example 2 of the LNG-RG system and the LAES system according to an embodiment of the present invention, and the coupling operating condition is based on the principle block diagram example 2 shown in FIG7 ;

[0111] For the third coupled operating condition, the shallow cooling energy from the LNG-RG system and the LAES system, as well as the deep cooling energy from the LNG-RG system and the LAES system, can be independently stored in the LAES system. The deep cooling energy and shallow cooling energy generated by the LAES system during the discharge condition can be sequentially obtained from the regasified main gas during the warming and expansion of the liquefied main gas.

[0112] As shown in FIG11 , FIG11 is a third example of a principle block diagram of LNG-RG and LAES in an embodiment of the present invention, which adds super-cold energy recovery and utilization on the basis of the second example of the principle block diagram of FIG7 .

[0113] Specifically, in some embodiments, the coupling method of LNG-RG and LAES in the embodiments of the present invention may also include: when the LAES system is in a charging condition, outputting the super-cold energy of the reflux main gas generated under the charging condition of the LAES system to the main gas that has absorbed the cryogenic energy but has not been expanded and liquefied; wherein the quality of the super-cold energy is higher than that of the cryogenic energy.

[0114] Specifically, the recovery and release of the super-cold energy of the return main gas can be achieved by simultaneously connecting heat exchange equipment or cold storage equipment to the main gas liquefaction path and the return main gas path.

[0115] As shown in FIG12 , FIG12 is a fifth coupling operating condition example 2 of the LNG-RG system and the LAES system according to an embodiment of the present invention, and the coupling operating condition is based on the principle block diagram example 2 shown in FIG7 ;

[0116] For the fifth coupling condition, the LAES system cuts off the cold energy exchange with the LNG-RG system. Under the charging condition, the independently stored shallow cold energy and deep cold energy are output to the main gas in sequence along the flow direction of the main gas of the LAES system under the charging condition; while under the discharging condition, the deep cold energy and shallow cold energy are obtained in sequence from the regasified main gas in the process of heating and expansion of the liquefied main gas along the air regasification direction for independent storage.

[0117] In the embodiment of the present invention, the natural gas on the LNG-RG system's liquefied natural gas regasification path is used as a cold energy carrier to directly exchange cold energy in the LAES system; or, other heat exchange media are used as cold energy carriers to indirectly exchange cold energy with the LAES system. Among them, using the natural gas on the liquefied natural gas regasification path as a cold energy carrier to exchange cold energy with the main gas means that the natural gas and the main gas are exchanged cold energy in the same heat exchanger, while using other heat exchange media as a cold energy carrier to exchange cold energy with the main gas means that an additional heat exchange medium is added between the natural gas and the main gas, and the cold energy of the natural gas is transferred to the main gas for liquefaction through the heat exchange medium, and the heat energy of the main gas is transferred to the natural gas for regasification.

[0118] Preferably, the LNG-RG system and the LAES system in the embodiment of the present invention can use other heat exchange media as cold energy carriers to exchange cold energy with the main gas.

[0119] In some embodiments, the LAES system's own cold storage equipment may include: a shallow cold tank (shallow cold storage equipment) for storing and releasing shallow cold energy, and a cryogenic tank (cryogenic cold storage equipment) for storing and releasing deep cold energy. The shallow cold tank's hot end temperature is between ambient temperature and zero degrees Celsius, but not below zero degrees Celsius, and its cold end temperature is the shallow cold temperature. The cryogenic tank's hot end temperature is the shallow cold temperature, and its cold end temperature is the liquid-to-gas phase transition temperature during LNG regasification. The choice of the shallow cold temperature is determined by the LAES system's operating parameters and the compressor's actual low-temperature operating performance and parameters.

[0120] In some embodiments, the coupling method of liquefied natural gas regasification and liquid air energy storage in the embodiments of the present invention can be implemented by adapting a corresponding coupling system according to its coupling conditions and performance. The embodiments of the present invention do not limit the coupling system, as long as the coupling method in the embodiments of the present invention can be implemented.

[0121] In order to facilitate those skilled in the art to quickly understand the main concept of the present application, an example of a coupling system of LNG-RG and LAES is also disclosed in the embodiment of the present invention, as shown in Figure 13. Figure 13 is an example of the structure of the coupling system of LNG-RG and LAES in the embodiment of the present invention; the coupling system includes: an LNG-RG system and a LAES system; the LNG-RG system includes: a deep cold natural gas heat exchanger HX-NG1 and a shallow cold natural gas heat exchanger HX-NG2 in the liquefied natural gas regasification path sequentially connected along the liquefied natural gas regasification direction; the LAES system includes: a hollow gas heat exchanger HX-NG1 in the main gas liquefaction path sequentially connected along the main gas liquefaction direction. Gas purification equipment (not shown), a first shallow cold charging heat exchanger HX-SC1, a compressor C, a second shallow cold charging heat exchanger HX-SC2, a deep cold charging heat exchanger HX-CB, a cryogenic expander CE, a liquid-gas separator LAS, and a liquid air storage tank LAD; along the direction of liquefied main gas regasification, the liquid air storage tank LAD, a cryogenic pump CP, a deep cold discharge heat exchanger HX-DC1, a deep cold discharge heat exchanger HX-DC2, an external heat source, and an expander E are sequentially connected in the liquefied main gas regasification path; wherein, the liquid air storage tank LAD on the main gas liquefaction path and the liquefied main gas regasification path is the same; and, a shallow cold tank SCD and a deep cold tank DCD;

[0122] Among them, the shallow-cooled natural gas heat exchanger HX-NG2 and the first shallow-cooled charging heat exchanger HX-SC1 form a first shallow-cooled closed loop for exchanging cold energy using the first shallow-cooled heat exchange medium; in the first shallow-cooled closed loop, the shallow-cooled natural gas heat exchanger HX-NG2 and the first shallow-cooled charging heat exchanger HX-SC1 are connected at the hot end and the cold end respectively;

[0123] Among them, the first shallow cooling charging heat exchanger HX-SC1, the second shallow cooling charging heat exchanger HX-SC2, the shallow cooling tank SCD and the shallow cooling discharge heat exchanger HX-DC2 form a second shallow cooling closed loop for exchanging cold energy with the second shallow cooling heat exchange medium; in the second shallow cooling closed loop, the hot ends of the first shallow cooling charging heat exchanger HX-SC1, the second shallow cooling charging heat exchanger HX-SC2, the shallow cooling tank SCD and the shallow cooling discharge heat exchanger HX-DC2 are respectively connected, and the cold ends are respectively connected.

[0124] Among them, the cryogenic natural gas heat exchanger HX-NG1 and the cryogenic charging heat exchanger HX-CB form a first cryogenic closed loop for exchanging cold energy using the first cryogenic heat exchange medium; in the first cryogenic closed loop, the hot ends of the cryogenic natural gas heat exchanger HX-NG1 and the cryogenic charging heat exchanger HX-CB are connected respectively, and the cold ends are connected respectively;

[0125] Among them, the cryogenic charging heat exchanger HX-CB, the cryogenic tank DCD, and the cryogenic discharge heat exchanger HX-DC1 form a second cryogenic closed loop for exchanging cold energy with a second cryogenic heat exchange medium; in the second cryogenic closed loop, the hot ends of the cryogenic charging heat exchanger HX-CB, the cryogenic tank DCD, and the cryogenic discharge heat exchanger HX-DC1 are connected respectively, and the cold ends are connected respectively.

[0126] The first shallow heat exchange medium and the second shallow heat exchange medium in the embodiment of the present invention can use the same or different heat exchange media, as long as they maintain a stable fluid state within the defined shallow cold energy temperature range; preferably, the first shallow heat exchange medium and the second shallow heat exchange medium can use methanol; similarly, the first deep cold heat exchange medium and the second deep cold heat exchange medium can use the same or different heat exchange media, as long as they maintain a stable fluid state within the defined deep cold energy temperature range; preferably, the first deep cold heat exchange medium and the second deep cold heat exchange medium can use propane.

[0127] As shown in FIG14 , FIG14 is a third example of a first coupling operating condition of the LNG-RG system and the LAES system according to an embodiment of the present invention, and the coupling operating condition is based on the first structural example shown in FIG13 ;

[0128] When the LNG-RG system is running and the LAES system is in the charging condition, the first shallow cooling heat exchange medium in the first shallow cooling closed loop circulates in the flow direction of the shallow cooling natural gas heat exchanger HX-NG2 cold end, the first shallow cooling charging heat exchanger HX-SC1 cold end, the first shallow cooling charging heat exchanger HX-SC1 hot end, and the shallow cooling natural gas heat exchanger HX-NG2 hot end.

[0129] The second shallow cooling heat exchange medium in the second shallow cooling closed loop circulates in the flow direction of the first shallow cooling charging heat exchanger HX-SC1 hot end, the shallow cooling tank SCD hot end, the shallow cooling tank SCD cold end, and the first shallow cooling charging heat exchanger HX-SC1 cold end; and circulates in the flow direction of the shallow cooling tank SCD cold end, the second shallow cooling charging heat exchanger HX-SC2 cold end, the second shallow cooling charging heat exchanger HX-SC2 hot end, and the shallow cooling tank SCD hot end;

[0130] The first cryogenic heat exchange medium in the first cryogenic closed loop maintains a flow cycle through the cold end of the cryogenic natural gas heat exchanger HX-NG1, the cold end of the cryogenic charging heat exchanger HX-CB, the hot end of the cryogenic charging heat exchanger HX-CB, and the hot end of the cryogenic natural gas heat exchanger HX-NG1.

[0131] The second cryogenic heat exchange medium in the second cryogenic closed loop circulates in the flow direction of the cryogenic charging heat exchanger HX-CB hot end, the cryogenic tank DCD hot end, the cryogenic tank DCD cold end, and the cryogenic charging heat exchanger HX-CB cold end;

[0132] The main gas under the charging condition of the LAES system exchanges cold energy with the corresponding heat exchange medium in the first shallow cooling charging heat exchanger HX-SC1, the second shallow cooling charging heat exchanger HX-SC2, and the deep cooling charging heat exchanger HX-CB in turn.

[0133] As shown in FIG15 , FIG15 is a third example of a second coupling operating condition of the LNG-RG system and the LAES system according to an embodiment of the present invention, and this coupling operating condition is based on the first structural example shown in FIG13 ;

[0134] When the LNG-RG system is running and the LAES system is in a static condition, the first shallow cooling heat exchange medium in the first shallow cooling closed loop circulates in the flow direction of the shallow cooling natural gas heat exchanger HX-NG2 cold end, the first shallow cooling charging heat exchanger HX-SC1 cold end, the first shallow cooling charging heat exchanger HX-SC1 hot end, and the shallow cooling natural gas heat exchanger HX-NG2 hot end.

[0135] The first cryogenic heat exchange medium in the first cryogenic closed loop maintains a flow cycle through the cold end of the cryogenic natural gas heat exchanger HX-NG1, the cold end of the cryogenic charging heat exchanger HX-CB, the hot end of the cryogenic charging heat exchanger HX-CB, and the hot end of the cryogenic natural gas heat exchanger HX-NG1.

[0136] The second shallow cooling heat exchange medium in the second shallow cooling closed loop circulates through the cold end of the first shallow cooling charging heat exchanger HX-SC1, the cold end of the shallow cooling tank SCD, the hot end of the shallow cooling tank SCD, and the hot end of the first shallow cooling charging heat exchanger HX-SC1 to replenish shallow cooling energy for the shallow cooling tank SCD;

[0137] The second cryogenic heat exchange medium in the second cryogenic closed loop circulates in the flow direction of the cryogenic charging heat exchanger HX-CB cold end, the cryogenic tank DCD cold end, the cryogenic tank DCD hot end and the cryogenic charging heat exchanger HX-CB hot end to replenish cryogenic energy for the cryogenic tank DCD.

[0138] As shown in FIG16 , FIG16 is a third coupling operating condition example 3 of the LNG-RG system and the LAES system according to an embodiment of the present invention, and this coupling operating condition is based on the structural example 1 shown in FIG13 ;

[0139] When the LNG-RG system is running and the LAES system is in the discharging condition, the first shallow cooling heat exchange medium in the first shallow cooling closed loop circulates in the flow direction of the shallow cooling natural gas heat exchanger HX-NG2 cold end, the first shallow cooling charging heat exchanger HX-SC1 cold end, the first shallow cooling charging heat exchanger HX-SC1 hot end, and the shallow cooling natural gas heat exchanger HX-NG2 hot end.

[0140] The first cryogenic heat exchange medium in the first cryogenic closed loop maintains a flow cycle through the cold end of the cryogenic natural gas heat exchanger HX-NG1, the cold end of the cryogenic charging heat exchanger HX-CB, the hot end of the cryogenic charging heat exchanger HX-CB, and the hot end of the cryogenic natural gas heat exchanger HX-NG1.

[0141] The second shallow cooling heat exchange medium in the second shallow cooling closed loop circulates in the flow direction of the first shallow cooling charging heat exchanger HX-SC1 cold end, the shallow cooling tank SCD cold end, the shallow cooling tank SCD hot end, and the first shallow cooling charging heat exchanger HX-SC1 hot end; and circulates in the flow direction of the shallow cooling discharge heat exchanger HX-DC2 cold end, the shallow cooling tank SCD cold end, the shallow cooling tank SCD hot end, and the shallow cooling discharge heat exchanger HX-DC2 hot end to replenish shallow cooling energy for the shallow cooling tank SCD;

[0142] The second cryogenic heat exchange medium in the second cryogenic closed loop circulates through the cold end of the cryogenic charging heat exchanger HX-CB, the cold end of the cryogenic tank DCD, the hot end of the cryogenic tank DCD, and the hot end of the cryogenic charging heat exchanger HX-CB; and circulates through the cold end of the cryogenic discharge heat exchanger HX-DC1, the cold end of the cryogenic tank DCD, the hot end of the cryogenic tank DCD, and the hot end of the cryogenic discharge heat exchanger HX-DC1 to replenish cryogenic energy for the cryogenic tank DCD.

[0143] The liquefied main gas under the LAES system discharge condition exchanges cold energy with the corresponding heat exchange medium in the deep-cold discharge heat exchanger HX-DC1 and the shallow-cold discharge heat exchanger HX-DC2 in turn.

[0144] As shown in FIG17 , FIG17 is a fourth coupling operating condition example 3 of the LNG-RG system and the LAES system according to an embodiment of the present invention, and this coupling operating condition is based on the structural example 1 shown in FIG13 ;

[0145] The LAES system may also include: a gas phase passage running through the shallow natural gas heat exchanger HX-NG2 and the cryogenic natural gas heat exchanger HX-NG1, which is used to transport purified ambient air through the gas phase passage when the LNG-RG system is running and the LAES system is shut down or there is excess cold energy in the cold storage tank, and to exchange cold energy with the LNG-RG system in the shallow natural gas heat exchanger and the cryogenic natural gas heat exchanger in sequence.

[0146] The fifth coupling operating condition based on FIG13 is the normal charging, standing, and discharging operating condition of the LAES system after the LNG-RG system and the LAES system are decoupled, which will not be described in detail here.

[0147] As shown in FIG18 , FIG18 is a second structural example of the coupling system of the LNG-RG system and the LAES system in an embodiment of the present invention; this embodiment adds an ultra-cold charging heat exchanger HX-UC on the basis of the structural example 1 of FIG13 , thereby recovering and consuming ultra-cold energy under the charging condition of the LAES system, and further cooling the main gas that has absorbed the deep-cold energy.

[0148] As shown in FIG19 , an example of a coupling system of LNG-RG and LAES is also disclosed in an embodiment of the present invention. FIG19 is a structural example three of the coupling system of LNG-RG and LAES in an embodiment of the present invention. The coupling system includes: an LNG-RG system and a LAES system. The LNG-RG system includes: a cryogenic natural gas heat exchanger HX-NG1 and a shallow natural gas heat exchanger HX-NG2 in the liquefied natural gas regasification path sequentially connected along the liquefied natural gas regasification direction. The LAES system includes: an air purification device (not shown), a first shallow cold tank SCD1, a compressor C, a second shallow cold tank SCD2, a cryogenic tank DCD, a low-temperature expander CE, a liquid-gas separator LAS and a liquid air storage tank LAD in the main gas liquefaction direction. The liquid air storage tank LAD, cryogenic pump CP, deep cold tank DCD, second shallow cold tank SCD2, first expander, first shallow cold tank SCD1, and second expander are included in the figure; the liquid air storage tank LAD on the main gas liquefaction path and the liquefied main gas regasification path are the same; the main gas liquefaction path and the liquefied main gas path pass through the first shallow cold tank SCD1, the second shallow cold tank SCD2, and the deep cold tank DCD, and directly exchange cold energy with the cold storage medium in the tank body, and the main gas liquefaction path and the liquefied main gas regasification path in the first shallow cold tank SCD1, the second shallow cold tank SCD2, and the deep cold tank DCD are the same path, but the air flow direction is opposite; not shown, along the liquefied main gas regasification path, an external heat source can be connected between the second shallow cold tank SCD2 and the first expander E1, and an external heat source can be connected between the first shallow cold tank SCD1 and the second expander E2.

[0149] A shallow cooling closed circuit for exchanging cold energy using a shallow cooling medium is formed between the shallow cooling natural gas heat exchanger HX-NG2, the first shallow cooling tank SCD1 and the second shallow cooling tank SCD2; wherein the hot ends and cold ends of the shallow cooling natural gas heat exchanger HX-NG2, the first shallow cooling tank SCD1 and the second shallow cooling tank SCD2 are respectively connected.

[0150] A cryogenic closed circuit is formed between the cryogenic natural gas heat exchanger HX-NG1 and the cryogenic tank DCD, in which cold energy is exchanged using a cryogenic heat exchange medium. In the cryogenic closed circuit, the hot ends and the cold ends of the cryogenic natural gas heat exchanger HX-NG1 and the cryogenic tank DCD are connected respectively.

[0151] Under the first, second, and third coupled operating conditions, the shallow cold heat exchange medium circulates through the cold end of the shallow natural gas heat exchanger, the cold end of the first shallow cold tank, the hot end of the first shallow cold tank, and the hot end of the shallow natural gas heat exchanger. Furthermore, the shallow cold heat exchange medium circulates through the cold end of the shallow natural gas heat exchanger, the cold end of the second shallow cold tank, the hot end of the second shallow cold tank, and the hot end of the shallow natural gas heat exchanger. The cryogenic heat exchange medium circulates through the cold end of the cryogenic natural gas heat exchanger, the cold end of the cryogenic tank, the hot end of the cryogenic tank, and the hot end of the cryogenic natural gas heat exchanger.

[0152] Figure 20 illustrates Example 5 of the first coupled operating condition of the LNG-RG system and the LAES system according to an embodiment of the present invention, applicable to Example 3 of the coupled system structure shown in Figure 19. First Coupling Condition: When the LNG-RG system is operating and the LAES system is in the charging state, the cold energy generated by the LNG-RG system and the cold energy stored by the LAES system are jointly output to the main gas in the LAES system's charging state, achieving LNG regasification and main gas liquefaction.

[0153] Figure 21 illustrates Example 4 of the second coupling operating condition of the LNG-RG system and the LAES system in an embodiment of the present invention; this is applicable to Structural Example 3 of the coupled system shown in Figure 19. In the second coupling operating condition, when the LNG-RG system is operating and the LAES system is in a static state, the cold energy generated by the LNG-RG system is exported to the LAES system for storage, achieving both LNG regasification and cold storage in the LAES system.

[0154] Figure 22 illustrates Example 4 of the third coupled operating condition of the LNG-RG system and the LAES system according to an embodiment of the present invention, and is applicable to Example 3 of the coupled system structure shown in Figure 19. When the LNG-RG system is operating and the LAES system is in a discharge operating condition, the cold energy generated by the LNG-RG system and the cold energy generated by the LAES system in the discharge operating condition are jointly output to the LAES system for storage, achieving LNG regasification, liquefied main gas regasification, and cold storage in the LAES system.

[0155] In the three coupled working conditions shown in Figures 20, 21, and 22, the cold storage and cold energy exchange equipment are combined into one, including the shallow cold storage equipment and the shallow cold energy exchange equipment combined into one, and the deep cold storage equipment and the deep cold energy exchange equipment combined into one; the liquefaction path of the main gas and the regasification path of the liquid main gas directly exchange cold energy with the cold storage medium in the cold storage equipment.

[0156] The fourth coupling working condition can refer to the example shown in FIG17 , which will not be described in detail here.

[0157] Under the fifth coupling condition, the shallow cooling closed loop and the deep cooling closed loop are both disconnected, and the shallow cooling heat exchange medium and the deep cooling heat exchange medium do not circulate.

[0158] As shown in FIG23 , FIG23 is a fourth example of the coupling system structure of LNG-RG and LAES in an embodiment of the present invention; this embodiment adds an ultra-cold tank UCD on the basis of the structural example 3 of FIG19 , thereby recovering and consuming ultra-cold energy under the charging condition of the LAES system, and further cooling the main gas that has absorbed the deep-cold energy.

[0159] Those skilled in the art should understand that the coupling system in the embodiment of the present invention may include a number of valve bodies to control the switching between various paths, cycles, and loops (between various coupling working conditions) in the coupling system; among them, using valve bodies to control the on-off state of pipelines is a conventional technology in this field. In addition, through the diagrams in the coupling working condition examples in the embodiments of the present invention, the solid line indicates connection (activation) and the dotted line indicates blocking (shutdown), which can also clearly indicate the on-off state under various working conditions. The present invention will not elaborate on this.

[0160] In the LAES system of the present invention, the shallow cold storage tank (SCD) and deep cold storage tank (DCD) can be configured as one or more series / parallel tank structures (not shown). The specific design can be based on the cold storage and release requirements of the cold storage tanks in the LAES system. In some embodiments, the number of shallow cold storage tanks (SCD) and deep cold storage tanks (DCD) in the LAES system can be configured based on the cold release requirements. Multiple shallow cold storage tanks and deep cold storage tanks can be configured to meet the flexible coupling requirements of LNG-RG and LAES operating modes. In this embodiment, the SCD and DCD are solid packed beds, using a fluid heat exchange medium for cold energy exchange.

[0161] Another object of the present invention is to provide a coupling system of LNG-RG and LAES to solve the problems existing in the prior art; as shown in Figure 24, Figure 24 is an example of a system block diagram of the coupling system of LNG-RG and LAES in an embodiment of the present invention, the coupling system 100 includes: a dynamic monitoring module 110 for monitoring the current status of the LNG-RG system and the LAES system; a first coupling control module 120 for outputting the cold energy generated by the LNG-RG system and the cold energy stored in the LAES system to the main gas in the charging condition of the LAES system when the LNG-RG system is running and the LAES system is in the charging condition; , realizing the regasification of LNG and the liquefaction of the main gas; the second coupling control module 130 is used to output the cold energy generated by the LNG-RG system to the LAES system for storage when the LNG-RG system is running and the LAES system is in a static working condition, thereby realizing the regasification of LNG and the cold storage of the LAES system; the third coupling control module 140 is used to output the cold energy generated by the LNG-RG system and the cold energy generated under the discharge working condition of the LAES system to the LAES system for storage when the LNG-RG system is running and the LAES system is in a discharge working condition, thereby realizing the regasification of LNG, the regasification of the liquefied main gas and the cold storage of the LAES system.

[0162] In some embodiments, the coupling system further includes: a fourth coupling control module 150, which is used to output the cold energy generated by the LNG-RG system to the ambient air bypassing the LAES system when the LNG-RG system is running and the LAES system is shut down or has excess cold storage, thereby achieving LNG regasification.

[0163] In some embodiments, the coupling system further includes: a fifth coupling control module 160, configured to cut off the cold energy exchange between the LNG-RG system and the LAES system when the LNG-RG system is shut down.

[0164] In some embodiments, the coupled system further includes: a cold storage tank for storing cold energy of the LNG-RG system and the LAES system, and the main gas liquefaction path and the liquid main gas regasification path of the LAES system are arranged outside the cold storage tank.

[0165] In some embodiments, the coupling system further includes: a cold storage tank for storing cold energy of the LNG-RG system and the LAES system, the main gas liquefaction path and the liquid main gas regasification path of the LAES system pass through the cold storage tank, and directly exchange cold energy with the cold storage medium in the cold storage tank; in the cold storage tank, the main gas liquefaction path and the liquid main gas regasification path are the same path but the airflow directions are opposite.

[0166] In some embodiments, natural gas on the LNG-RG system's liquefied natural gas regasification path is used as a cold energy carrier to directly exchange cold energy with the LAES system; or, other heat exchange media are used as a cold energy carrier to indirectly exchange cold energy with the LAES system.

[0167] In some embodiments, cold energy is divided into deep cold energy and shallow cold energy according to quality.

[0168] In some embodiments, the first coupling control module 120 is used to output the shallow cooling energy of the LNG-RG system and the LAES system, and the deep cooling energy of the LNG-RG system and the LAES system, to the main gas in sequence along the flow direction of the main gas under charging conditions.

[0169] In some embodiments, the second coupling control module 130 is configured to output the deep cooling energy and shallow cooling energy of the LNG-RG system to the LAES system for independent storage.

[0170] In some embodiments, the third coupling control module 140 is configured to output the shallow cooling energy under the discharge conditions of the LNG-RG system and the LAES system, and the deep cooling energy under the discharge conditions of the LNG-RG system and the LAES system, to the LAES system for independent storage.

[0171] In some embodiments, the LAES system includes: a shallow cold tank for storing and releasing shallow cold energy, and a cryogenic tank for storing and releasing deep cold energy; wherein the hot end temperature of the shallow cold tank is between the ambient temperature and zero degrees Celsius but not lower than zero degrees Celsius, and its cold end temperature is the shallow cold temperature; the hot end temperature of the cryogenic tank is the shallow cold temperature, and its cold end temperature is the liquid-gas phase transition temperature during LNG regasification.

[0172] In some embodiments, the first coupling module 120 is used to jointly output the shallow cold energy of the LNG-RG system and the LAES system to the main gas in the LAES system that has undergone air purification but has not undergone one or more stages of compression, and the main gas that has undergone one or more stages of compression but has not absorbed deep cold energy; and to jointly output the deep cold energy of the LNG-RG system and the LAES system to the main gas in the LAES system that has absorbed the shallow cold energy but has not been expanded and liquefied.

[0173] In some embodiments, the first coupling module 120 is further configured to output the super-cold energy of the reflux main gas generated in the LAES system charging condition to the main gas that has absorbed the cryogenic energy but has not been expanded and liquefied when the LAES system is in the charging condition; wherein the quality of the super-cold energy is higher than that of the cryogenic energy.

[0174] In some embodiments, the cryogenic energy and shallow refrigeration energy generated by the LAES system under discharge conditions are sequentially obtained from the regasified main gas during the process of temperature increase and expansion of the liquefied main gas.

[0175] 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 coupling method of LNG-RG and LAES, characterized in that: include: When the LNG-RG system is running and the LAES system is in the charging state, the cold energy generated by the LNG-RG system and the cold energy stored in the LAES system are output to the main gas in the LAES system charging state, thereby realizing the regasification of LNG and the liquefaction of the main gas. When the LNG-RG system is running and the LAES system is in a static state, the cold energy generated by the LNG-RG system is output to the LAES system for storage, realizing the regasification of LNG and the cold storage of the LAES system; When the LNG-RG system is running and the LAES system is in the discharge condition, the cold energy generated by the LNG-RG system and the cold energy generated by the LAES system in the discharge condition are output to the LAES system for storage, realizing the regasification of LNG, the regasification of liquefied main gas and the cold storage of the LAES system.

2. The coupling method according to claim 1, wherein: Also includes: When the LNG-RG system is running and the LAES system is shut down or has excess cold storage, the cold energy generated by the LNG-RG system bypasses the LAES system and is output to the ambient air to achieve LNG regasification.

3. The coupling method according to claim 1, wherein: Also includes: When the LNG-RG system is shut down, the cold energy exchange between the LNG-RG system and the LAES system is cut off.

4. The coupling method according to claim 1, wherein: The natural gas in the regasification process of the LNG-RG system is used as a cold energy carrier to directly exchange cold energy in the LAES system; or other heat exchange media are used as cold energy carriers to indirectly exchange cold energy with the LAES system.

5. The coupling method according to claim 1, characterized in that: Split cold energy into deep cold energy and shallow cold energy according to quality; When the LNG-RG system is in operation and the LAES system is in a charging state, the cold energy generated by the LNG-RG system and the cold energy stored in the LAES system are jointly output to the main gas in the charging state of the LAES system to achieve the regasification of LNG and liquefaction of the main gas, including: The shallow cooling energy of the LNG-RG system and the LAES system, as well as the deep cooling energy of the LNG-RG system and the LAES system, are sequentially output to the main gas along the flow direction of the main gas under charging conditions; When the LNG-RG system is in operation and the LAES system is in a static state, the cold energy generated by the LNG-RG system is output to the LAES system for storage, thereby realizing the regasification of LNG and the cold storage of the LAES system, including: The deep cold energy and shallow cold energy of the LNG-RG system are respectively output to the LAES system for independent storage; When the LNG-RG system is in operation and the LAES system is in a discharge condition, the cold energy generated by the LNG-RG system and the cold energy generated by the LAES system in the discharge condition are output to the LAES system for storage, thereby realizing the regasification of LNG, the regasification of liquefied main gas, and the cold storage of the LAES system, including: The shallow cold energy under the discharge working condition of the LNG-RG system and the LAES system, and the deep cold energy under the discharge working condition of the LNG-RG system and the LAES system are respectively output to the LAES system for independent storage.

6. The coupling method according to claim 5, characterized in that: The LAES system includes: a shallow cold tank for storing and releasing shallow cold energy, and a cryogenic tank for storing and releasing deep cold energy; Among them, the hot end temperature of the shallow cooling tank is between the ambient temperature and zero degrees Celsius but not lower than zero degrees Celsius, and its cold end temperature is the shallow cooling temperature; the hot end temperature of the deep cooling tank is the shallow cooling temperature, and its cold end temperature is the liquid-gas phase transition temperature during LNG regasification.

7. The coupling method according to claim 5, characterized in that: The process of sequentially outputting the shallow cooling energy of the LNG-RG system and the LAES system, and the deep cooling energy of the LNG-RG system and the LAES system to the main gas along the flow direction of the main gas under the charging condition, includes: The shallow cold energy of the LNG-RG system and the LAES system is jointly outputted to the main gas in the LAES system that has undergone air purification but has not undergone one or more stages of compression, and the main gas that has undergone one or more stages of compression but has not absorbed the deep cold energy; The deep cold energy of the LNG-RG system and the LAES system is jointly output to the main gas in the LAES system after absorbing the shallow cold energy but not expanding and liquefying.

8. The coupling method according to claim 7, characterized in that: Also includes: When the LAES system is in a charging state, the super-cold energy of the reflux main gas generated in the LAES system charging state is output to the main gas that has absorbed the cryogenic energy but has not been expanded and liquefied; wherein the quality of the super-cold energy is higher than that of the cryogenic energy.

9. The coupling method according to claim 5, characterized in that: The deep cold energy and shallow cold energy generated by the LAES system under discharge conditions are successively obtained from the regasified main gas during the heating and expansion process of the liquefied main gas.

10. A coupling system of LNG-RG and LAES, characterized in that: include: Dynamic monitoring module, used to monitor the current status of the LNG-RG system and LAES system; The first coupling control module is configured to output the cold energy generated by the LNG-RG system and the cold energy stored in the LAES system to the main gas in the LAES system charging state when the LNG-RG system is in operation and the LAES system is in the charging state, thereby achieving regasification of the LNG and liquefaction of the main gas; The second coupling control module is used to output the cold energy generated by the LNG-RG system to the LAES system for storage when the LNG-RG system is running and the LAES system is in a static working state, thereby realizing the regasification of LNG and the cold storage of the LAES system; The third coupling control module is used to output the cold energy generated by the LNG-RG system and the cold energy generated by the LAES system under the discharge condition to the LAES system for storage when the LNG-RG system is running and the LAES system is in the discharge condition, thereby realizing the regasification of LNG, the regasification of liquefied main gas and the cold storage of the LAES system.

11. The coupling system according to claim 10, characterized in that Also includes: The fourth coupling control module is used to output the cold energy generated by the LNG-RG system to the ambient air, bypassing the LAES system, when the LNG-RG system is running and the LAES system is shut down or has excess cold storage, to achieve LNG regasification.

12. The coupling system according to claim 10, characterized in that Also includes: The fifth coupling control module is used to cut off the cold energy exchange between the LNG-RG system and the LAES system when the LNG-RG system is shut down.

13. The coupling system according to claim 10, characterized in that Also includes: A cold storage tank is used to store cold energy of the LNG-RG system and the LAES system, and the main gas liquefaction path and the liquid main gas regasification path of the LAES system are arranged outside the cold storage tank.

14. The coupling system according to claim 10, characterized in that Also includes: A cold storage tank is used to store the cold energy of the LNG-RG system and the LAES system. The main gas liquefaction path and the liquid main gas regasification path of the LAES system pass through the cold storage tank and directly exchange cold energy with the cold storage medium in the cold storage tank. In the cold storage tank, the main gas liquefaction path and the liquid main gas regasification path are the same path but the airflow directions are opposite.

15. The coupling system according to claim 10, characterized in that The natural gas on the LNG-RG system's liquefied natural gas regasification path is used as a cold energy carrier to directly exchange cold energy in the LAES system; or other heat exchange media are used as cold energy carriers to indirectly exchange cold energy with the LAES system.

16. The coupling system according to claim 10, characterized in that Split cold energy into deep cold energy and shallow cold energy according to quality; The first coupling control module is used to output the shallow cooling energy of the LNG-RG system and the LAES system, and the deep cooling energy of the LNG-RG system and the LAES system, to the main gas in sequence along the flow direction of the main gas under the charging condition; The second coupling control module is used to output the deep cold energy and shallow cold energy of the LNG-RG system to the LAES system for independent storage; The third coupling control module is used to output the shallow cooling energy under the discharge working conditions of the LNG-RG system and the LAES system, and the deep cooling energy under the discharge working conditions of the LNG-RG system and the LAES system, to the LAES system for independent storage.

17. The coupling system according to claim 16, characterized in that The LAES system includes: a shallow cold tank for storing and releasing shallow cold energy, and a cryogenic tank for storing and releasing deep cold energy; Among them, the hot end temperature of the shallow cooling tank is between the ambient temperature and zero degrees Celsius but not lower than zero degrees Celsius, and its cold end temperature is the shallow cooling temperature; the hot end temperature of the deep cooling tank is the shallow cooling temperature, and its cold end temperature is the liquid-gas phase transition temperature during LNG regasification.

18. The coupling system according to claim 16, characterized in that The first coupling module is used to output the shallow cold energy of the LNG-RG system and the LAES system to the main gas in the LAES system that has undergone air purification but has not undergone one or more stages of compression, and the main gas that has undergone one or more stages of compression but has not absorbed the deep cold energy; as well as, The deep cold energy of the LNG-RG system and the LAES system is jointly output to the main gas in the LAES system after absorbing the shallow cold energy but not expanding and liquefying.

19. The coupling system according to claim 16, wherein: The first coupling module is further configured to output the super-cold energy of the reflux main gas generated under the charging condition of the LAES system to the main gas that has absorbed the cryogenic energy but has not been expanded and liquefied, when the LAES system is in the charging condition; wherein the quality of the super-cold energy is higher than that of the cryogenic energy.

20. The coupling system according to claim 16, wherein: The deep cold energy and shallow cold energy generated by the LAES system under discharge conditions are successively obtained from the regasified main gas during the heating and expansion process of the liquefied main gas.

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