Method and system for coupling liquefied natural gas regasification and liquid air energy storage

Abstract

The application discloses a liquefied natural gas regasification and liquid air energy storage coupling method and system, and relates to the technical field of large-scale energy storage.The coupling method comprises the following steps: when the LNG-RG system is running and the LAES system is in a charging condition, outputting the cold energy generated by the LNG-RG system and the cold energy stored by the LAES system to main gas in the charging condition of the LAES system; when the LNG-RG system is running and the LAES system is in a static condition, outputting the cold energy generated by the LNG-RG system to the LAES system for storage; and when the LNG-RG system is running and the LAES system is in a discharging condition, outputting the cold energy generated by the LNG-RG system and the cold energy generated in the discharging condition of the LAES system to the LAES system for storage.In the embodiment of the application, the cold energy and the heat energy can be effectively coupled and utilized between the LAES system and the LNG-RG system in any one of the charging condition, the static condition and the discharging condition of the LAES system, the coupling system is improved, and the output requirements of the LNG-RG system and the LAES system can be met in multiple conditions.

Description

Technical Field

[0001] This invention belongs to the field of large-scale energy storage technology, and in particular relates to a coupling method and system for liquefied natural gas regasification and liquid air energy storage. Background Technology

[0002] Liquid air energy storage (LAES), as a type of energy storage technology, works by using inexpensive off-peak electricity to absorb air from the environment, then cooling it until it becomes a liquid for storage. During peak electricity demand, the liquid air is released from the tank, pressurized and heated, and then fed into an expander to generate electricity, thus achieving peak-shaving and playing an important role in grid peak regulation. However, there is a loss of cold energy during charging and discharging, and to replenish this lost cold energy, additional electrical energy is usually required, resulting in high costs.

[0003] In recent years, natural gas, as a clean energy source, has steadily increased its share in energy consumption. Especially 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 LNG regasification (RG) processes; the process of reheating LNG into natural gas releases a large amount of cold energy, making the coupled application of LAES (Laminated Air Emission System) and LNG-RG systems extremely significant in practical application and promising in the future.

[0004] Currently, scholars and manufacturers at home and abroad have proposed several coupling models for LAES systems and LNG-RG systems. However, these models do not take into account the continuous operation of LNG-RG systems and LAES systems under various operating conditions. The coupling system is imperfect, and the effective coupling utilization rate of cold and hot energy between the systems is low. Summary of the Invention

[0005] In view of this, one objective 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 imperfect coupling system between LAES and LNG-RG systems, low effective coupling utilization rate of cold and hot energy between systems, and inability to meet the output requirements of LNG-RG and LAES systems under multiple operating conditions.

[0006] 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 charging condition, outputting the cold energy generated by the LNG-RG system and the cold energy stored in the LAES system together to the main gas in the charging condition of the LAES system to achieve LNG regasification and main gas liquefaction; when the LNG-RG system is operating and the LAES system is in stagnant condition, outputting the cold energy generated by the LNG-RG system to the LAES system for storage to achieve LNG regasification and LAES system cold storage; when the LNG-RG system is operating and the LAES system is in discharging condition, outputting the cold energy generated by the LNG-RG system and the cold energy generated in the discharging condition of the LAES system together to the LAES system for storage to achieve LNG regasification, regasification of liquefied main gas, and LAES system cold storage.

[0007] 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 to achieve LNG regasification.

[0008] In some alternative embodiments, the coupling method further includes cutting off the cold energy exchange between the LNG-RG system and the LAES system when the LNG-RG system is shut down.

[0009] In some alternative embodiments, natural gas from the LNG-RG system regasification process is used as a cold energy carrier for direct cold energy exchange in the LAES system; or, other heat exchange media are used as cold energy carriers for indirect cold energy exchange with the LAES system.

[0010] In some alternative embodiments, the cold energy is divided into deep cold energy and shallow cold energy according to its quality.

[0011] In some optional embodiments, the process of outputting the cold energy generated by the LNG-RG system and the cold energy stored in the LAES system to the main gas under the charging condition when the LNG-RG system is operating and the LAES system is in charging condition, thereby realizing the regasification of LNG and the liquefaction of the main gas, includes: outputting the shallow cold energy and 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.

[0012] In some optional embodiments, the process of outputting the cold energy generated by the LNG-RG system to the LAES system for storage when the LNG-RG system is operating and the LAES system is in a static state, thereby realizing the regasification of LNG and the cold storage of the LAES system, includes: outputting the deep cold energy and shallow cold energy of the LNG-RG system to the LAES system for independent storage.

[0013] In some optional embodiments, when the LNG-RG system is operating and the LAES system is in discharge condition, the cold energy generated by the LNG-RG system and the cold energy generated by the LAES system in discharge condition are jointly 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, including: outputting the shallow cold energy and the deep cold energy of the LNG-RG system and the LAES system in discharge condition to the LAES system for independent storage respectively.

[0014] In some alternative embodiments, the LAES system includes: a shallow cryogenic tank for storing and releasing shallow cryogenic energy, and a deep cryogenic tank for storing and releasing deep cryogenic energy; wherein the hot end temperature of the shallow cryogenic 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 cryogenic temperature; the hot end temperature of the deep cryogenic tank is the shallow cryogenic temperature, and its cold end temperature is the liquid-gas phase change temperature during LNG regasification.

[0015] In some optional embodiments, the process of sequentially outputting the shallow cooling energy and deep cooling energy of the LNG-RG system and LAES system to the main gas along the flow direction of the main gas under charging conditions includes: outputting the shallow cooling energy of the LNG-RG system and 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 cooling energy; and outputting the deep cooling energy of the LNG-RG system and LAES system to the main gas in the LAES system that has absorbed shallow cooling energy but has not undergone expansion and liquefaction.

[0016] In some optional embodiments, the coupling method further includes: when the LAES system is charging, outputting the ultracold energy of the reflux main gas generated during the charging condition of the LAES system to the main gas that has absorbed cryogenic energy but has not been expanded and liquefied; wherein the quality of the ultracold energy is higher than that of the cryogenic energy.

[0017] In some alternative embodiments, the deep cryogenic energy and shallow cryogenic energy generated under the discharge conditions of the LAES system are successively obtained from the regasified main gas during the heating and expansion process of the liquefied main gas.

[0018] Another object of the present invention is to provide a coupling system for LNG-RG and LAES to solve the problems existing in the prior art.

[0019] In some illustrative embodiments, the LNG-RG and LAES coupling system includes: a dynamic monitoring module for monitoring the current state of the LNG-RG system and the LAES system; a first coupling control module 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 LAES system charging condition when the LNG-RG system is running and the LAES system is in charging condition, thereby realizing LNG regasification and main gas liquefaction; a second coupling control module for outputting 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 quiescent condition, thereby realizing LNG regasification and LAES system cold storage; and a third coupling control module for outputting the cold energy generated by the LNG-RG system and the cold energy generated in the LAES system discharging condition to the LAES system for storage when the LNG-RG system is running and the LAES system is in discharging condition, thereby realizing LNG regasification, liquefied main gas regasification, and LAES system cold storage.

[0020] In some optional embodiments, the coupling system further includes: a fourth coupling control module, used to bypass the LAES system and output the cold energy generated by the LNG-RG system to the ambient air when the LNG-RG system is running and the LAES system is shut down or has excess cold storage, thereby realizing the regasification of LNG.

[0021] In some alternative embodiments, the coupling system further includes a fifth coupling control module for cutting off the cold energy exchange between the LNG-RG system and the LAES system when the LNG-RG system is shut down.

[0022] In some alternative embodiments, the coupling system further includes a cold storage tank for storing the cold energy of the LNG-RG system and the LAES system, wherein the main gas liquefaction path and the liquid main gas regasification path of the LAES system are arranged outside the cold storage tank.

[0023] In some optional embodiments, the coupling system further includes: a cold storage tank for storing the cold energy of the LNG-RG system and the LAES system, wherein 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; within the cold storage tank, the main gas liquefaction path and the liquid main gas regasification path are the same path but with opposite airflow directions.

[0024] In some alternative embodiments, natural gas from the LNG-RG system's liquefied natural gas regasification path is used as a cold energy carrier for direct cold energy exchange within the LAES system; alternatively, other heat exchange media are used as cold energy carriers for indirect cold energy exchange with the LAES system.

[0025] In some alternative embodiments, the cold energy is divided into deep cold energy and shallow cold energy according to its quality.

[0026] In some optional embodiments, the first coupling control module is used to sequentially output 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, to the main gas along the flow direction of the main gas under charging conditions.

[0027] In some optional embodiments, the second coupling control module is used to output the deep cryogenic energy and shallow cryogenic energy of the LNG-RG system to the LAES system for independent storage.

[0028] In some optional embodiments, the third coupling control module is used to output the shallow cold energy and the deep cold energy under the discharge conditions of the LNG-RG system and the LAES system to the LAES system for independent storage.

[0029] In some alternative embodiments, the LAES system includes: a shallow cryogenic tank for storing and releasing shallow cryogenic energy, and a deep cryogenic tank for storing and releasing deep cryogenic energy; wherein the hot end temperature of the shallow cryogenic 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 cryogenic temperature; the hot end temperature of the deep cryogenic tank is the shallow cryogenic temperature, and its cold end temperature is the liquid-gas phase change temperature during LNG regasification.

[0030] 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 shallow cold energy but has not been expanded and liquefied.

[0031] In some optional embodiments, the first coupling module is further configured to output the ultracold energy of the reflux main gas generated during the charging operation of the LAES system to the main gas that has absorbed cryogenic energy but has not undergone expansion and liquefaction; wherein the quality of the ultracold energy is higher than that of the cryogenic energy.

[0032] In some alternative embodiments, the deep cryogenic energy and shallow cryogenic energy generated under the discharge conditions of the LAES system are successively obtained from the regasified main gas during the heating and expansion process of the liquefied main gas.

[0033] Compared with the prior art, this application has the following advantages:

[0034] This invention not only couples the operating conditions of the LNG-RG system with the charging conditions of the LAES system, but also separately couples the operating conditions of the LNG-RG system with the idling and discharging conditions of the LAES system. Regardless of whether the LAES system is in charging, idling, or discharging mode, effective coupling and utilization of cold and heat energy between the LNG-RG system and the LAES system can be achieved, thus perfecting the coupling system and meeting the output requirements of both the LNG-RG and LAES systems under multiple operating conditions. Simultaneously, while ensuring continuous operation of the LNG-RG system under various coupled operating conditions with the LAES system, the LAES system can switch operating conditions according to its actual needs. Attached Figure Description

[0035] Figure 1 This is an example of a principle block diagram of the LNG-RG system and LAES system in an embodiment of the present invention;

[0036] Figure 2 This is an example of the first coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention;

[0037] Figure 3 This is an example of the second coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention;

[0038] Figure 4 This is Example 1 of the third coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention;

[0039] Figure 5 This is Example 1 of the fourth coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention;

[0040] Figure 6 This is Example 1 of the fifth coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention;

[0041] Figure 7 This is Example 2 of the principle block diagram of the LNG-RG system and LAES system in the embodiments of the present invention;

[0042] Figure 8 This is Example 2 of the first coupling operation condition between the LNG-RG system and the LAES system in this embodiment of the invention;

[0043] Figure 9This is Example 2 of the second coupling operation between the LNG-RG system and the LAES system in this embodiment of the invention;

[0044] Figure 10 This is Example 2 of the third coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention;

[0045] Figure 11 This is Example 3 of the first coupled operating condition of the LNG-RG system and the LAES system in this embodiment of the invention;

[0046] Figure 12 This is Example 2 of the fourth coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention;

[0047] Figure 13 This is a structural example of the coupling system between the LNG-RG system and the LAES system in this embodiment of the invention;

[0048] Figure 14 This is Example 4 of the first coupling operation condition between the LNG-RG system and the LAES system in this embodiment of the invention;

[0049] Figure 15 This is Example 3 of the second coupling operation between the LNG-RG system and the LAES system in this embodiment of the invention;

[0050] Figure 16 This is Example 3 of the third coupling operation between the LNG-RG system and the LAES system in this embodiment of the invention;

[0051] Figure 17 This is Example 3 of the fourth coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention;

[0052] Figure 18 This is a second example of the structure of the coupled system of the LNG-RG system and the LAES system in this embodiment of the invention;

[0053] Figure 19 This is a third example of the structure of the coupled system of the LNG-RG system and the LAES system in this invention.

[0054] Figure 20 This is Example 5 of the first coupling operation condition between the LNG-RG system and the LAES system in this embodiment of the invention;

[0055] Figure 21 This is Example 4 of the second coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention;

[0056] Figure 22 This is Example 4 of the third coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention;

[0057] Figure 23 This is the fourth example of the structure of the coupling system between the LNG-RG system and the LAES system in this embodiment of the invention;

[0058] Figure 24 This is an example of a system block diagram of the coupled LNG-RG system and LAES system in an embodiment of the present invention.

[0059] Figure label:

[0060] Natural gas heat exchanger HX-NG (Heat Exchanger-Natural Gas), cryogenic natural gas heat exchanger HX-NG1 (Heat Exchanger-Natural Gas 1), and shallow cryogenic natural gas heat exchanger HX-NG2 (Heat Exchanger-Natural Gas 2);

[0061] The heat exchangers are: HX-SC1 (Shallow Cold 1), HX-SC2 (Shallow Cold 2), HX-CB (Cold Box), and HX-UC (Ultra Cold).

[0062] Shallow Cold Dewar (SCD), Shallow Cold Dewar 1 (SCD1), Shallow Cold Dewar 2 (SCD2), Deep Cold Dewar (DCD), Deep Cold Dewar 1 (DCD1), Deep Cold Dewar 2 (DCD2);

[0063] Heat exchanger HX-DC (Heat Exchanger-Discharge), cryogenic heat exchanger HX-DC1 (Heat Exchanger-Discharge 1), and shallow-cold heat exchanger HX-DC2 (Heat Exchanger-Discharge 2).

[0064] Compressor C, Cryogenic Expander CE, Liquid Air Separator LAS, Liquid Air Dewar LAD, Cryogenic Pump CP, Expander E, First Expander E1, Second Expander E2. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0066] It should be noted that, where there is no conflict, the various technical features in the embodiments of the present invention can be combined with each other.

[0067] Terminology Explanation:

[0068] The LNG-RG system, or liquefied natural gas regasification system, is used to convert liquefied natural gas (LNG) into natural gas (NG). It has a liquefied natural gas regasification path, in which LNG is converted into NG while releasing cold energy (and absorbing heat energy).

[0069] The LAES system, or Liquid Air Energy Storage System, is used to store energy by converting main gas (air) into liquefied main gas (liquid air) using electrical energy during charging, and to generate electrical energy by converting liquefied main gas into regasified main gas during discharging. It has a main gas liquefaction path and a liquefied main gas regasification path. The main gas absorbs cold energy (and releases heat energy) to become liquefied main gas in the main gas liquefaction path, and the liquefied main gas releases cold energy (and absorbs heat energy) to become regasified main gas in the air regasification path.

[0070] During the charging operation of the LAES system, the main gas refers to the portion of air that has been purified and passed through the main gas liquefaction path to become liquid air, excluding the return air that needs to recover cold energy; during the discharging operation of the LAES system, the liquefied main gas refers to both liquid air and regasified liquid air.

[0071] This invention discloses a coupling method for LNG-RG and LAES, specifically, as follows: Figure 1 As shown, Figure 1This is an example 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.

[0072] like Figure 2 As shown, Figure 2 This is an example of the first coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention. This coupling condition is based on Figure 1 Example 1 of the principle block diagram shown;

[0073] First coupling condition: When the LNG-RG system is running and the LAES system is in 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 in the charging condition of the LAES system to realize the regasification of LNG and the liquefaction of the main gas.

[0074] From the perspective of the LAES system, the main gas under charging conditions absorbs the cold energy generated during the LNG regasification process of the LNG-RG system and the cold energy stored in the LAES system's own cold storage equipment (such as cold storage tanks), thereby cooling the main gas. From the perspective of the LNG-RG system, the LNG in the LNG-RG system absorbs the heat energy from the main gas under charging conditions of the LAES system, thereby regasifying the LNG. In other words, the effective coupling and utilization of the cold energy from LNG regasification in the LNG-RG system, the cold energy stored in the LAES system itself, and the heat energy from the main gas under charging conditions of the LAES system are achieved.

[0075] like Figure 3 As shown, Figure 3 This is Example 1 of the second coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention. This coupling condition is based on Figure 1 Example 1 of the principle block diagram shown;

[0076] 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.

[0077] From the perspective of the LAES system, in its static state, only its own cold storage equipment participates in the cold energy exchange with the LNG-RG system. During this process, it increases its stored cold energy by absorbing the cold energy from the LNG regasification of the LNG in the LNG-RG system. From the perspective of the LNG-RG system, the LNG in the LNG-RG system absorbs heat energy from the cold storage equipment of the LAES system to achieve LNG regasification. This achieves effective coupling and utilization between the cold energy from the LNG regasification of the LNG in the LNG-RG system and the heat energy from the cold storage equipment of the LAES system itself.

[0078] In this embodiment of the invention, the static operating conditions of the LAES system include the static operating conditions after the LAES system is charged and the static operating conditions after the LAES system is discharged.

[0079] like Figure 4 As shown, Figure 4 This is Example 1 of the third coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention. This coupling condition is based on Figure 1 Example 1 of the principle block diagram shown;

[0080] The third coupling condition: When the LNG-RG system is running and the LAES system is in discharge condition, the cold energy generated by the LNG-RG system and the cold energy generated by the LAES system in discharge condition are jointly 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.

[0081] From the perspective of the LAES system, its own cold storage equipment simultaneously absorbs the cold energy generated during the regasification of the liquefied main gas under LAES system discharge conditions and the cold energy generated during LNG regasification in the LNG-RG system, thereby increasing its stored cold energy. The liquefied main gas absorbs heat energy from the cold storage equipment of the LAES system, realizing the regasification of the liquefied main gas / heating of the regasified main gas. From the perspective of the LNG-RG system, the LNG-RG system also absorbs heat energy from the cold storage equipment of the LAES system to realize LNG regasification. That is, it realizes the effective coupling and utilization of the cold energy of LNG regasification in the LNG-RG system, the cold energy of liquefied main gas regasification under LAES system discharge conditions, and the heat energy of the LAES system's own cold storage equipment.

[0082] Based on the first, second, and third coupling conditions, it is possible to ensure that the LNG-RG system can continuously produce regasified natural gas during operation, regardless of whether the LAES system is in charging, quiescent, or discharging condition, or even when the condition changes. This is particularly suitable for the actual situation of continuous production of the LNG-RG system and the periodic operation of the LAES system.

[0083] This invention not only couples the operating conditions of the LNG-RG system with the charging conditions of the LAES system, but also separately couples the operating conditions of the LNG-RG system with the idling and discharging conditions of the LAES system. Regardless of whether the LAES system is in charging, idling, or discharging mode, effective coupling and utilization of cold and heat energy between the LNG-RG system and the LAES system can be achieved, thus perfecting the coupling system and meeting the output requirements of both the LNG-RG and LAES systems under multiple operating conditions. Simultaneously, while ensuring continuous operation of the LNG-RG system under various coupled operating conditions with the LAES system, the LAES system can switch operating conditions according to its actual needs.

[0084] In some embodiments, the coupling method of liquefied natural gas regasification and liquid air energy storage in the present invention may further include a fourth coupling condition when the LNG-RG system is operating and the LAES system is shut down or has excess cold storage.

[0085] like Figure 5 As shown, Figure 5 This is Example 1 of the fourth coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention. This coupling condition is based on Figure 1 Example 1 of the principle block diagram shown;

[0086] Fourth coupling condition: 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 is bypassed by the LAES system and output to the ambient air to achieve LNG regasification.

[0087] In this embodiment, the LAES system may be shut down during its maintenance period, at which time the main equipment of the LAES system is unavailable and cannot provide heat energy to the LNG-RG system. Conversely, LAES system over-storage may occur during its idle period, when the LAES 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.

[0088] This embodiment couples the operating conditions of the LNG-RG system with the operating conditions of the LAES system shutdown and over-storage. This ensures that the LNG-RG system can maintain continuous operation by introducing purified ambient air from outside when the LAES system is shut down or when the LAES system has over-storage. It also avoids the LNG-RG system continuing to exchange cold energy with the LAES system when the LAES system has over-storage, which would result in insufficient release of cold energy from the LNG, reduced regasification efficiency, and consequently reduced production or excessively low temperature of the regasified natural gas.

[0089] Specifically, in certain circumstances, in this embodiment of the invention, outputting the cold energy generated by the LNG-RG system during operation to the ambient air by bypassing the LAES system means outputting the cold energy generated by the LNG-RG system during operation to the ambient air by bypassing the main gas liquefaction path and the liquefied main gas regasification path of the LAES system.

[0090] In one embodiment of the present invention, a gas phase passage independent of the LAES system can be established for the LNG-RG system. Under certain circumstances, purified ambient air is introduced and exchanged with LNG for cold energy, thereby allowing LNG to directly absorb heat energy from the ambient air to achieve LNG regasification. This gas phase passage can also be constructed using a portion of the piping in the LAES system that does not pass through the main LAES system equipment (e.g., compressor, cryogenic expander, liquid-gas separator, liquid air storage tank, expander, cold storage tank). This avoids conflict with the shutdown (maintenance) of the main LAES system equipment and eliminates the need for cold energy exchange with the LAES system, ensuring the normal operation of LNG regasification.

[0091] In some embodiments of the present invention, the coupling method of liquefied natural gas regasification and liquid air energy storage further includes a fifth coupling condition when the LNG-RG system is shut down and the LAES system is running (charging, resting, discharging).

[0092] like Figure 6 As shown, Figure 6 This is Example 1 of the fifth coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention. This coupling condition is based on Figure 1 Example 1 of the principle block diagram shown;

[0093] 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.

[0094] When the LNG-RG system is in shutdown condition, since the LNG-RG system is no longer regasifying LNG, it does not need to absorb heat energy from outside 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 can use 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.

[0095] The first to fifth coupling conditions in the embodiments of the present invention involve the coupling of operating conditions between the LNG-RG system and the LAES system, ensuring that the LNG-RG system and the LAES system, individually or in combination, meet the production requirements.

[0096] In some embodiments, the cold energy involved between the two systems is divided into deep cold energy and shallow cold energy according to the quality of the cold energy, wherein the quality of deep cold energy is higher than that of 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.

[0097] like Figure 7 As shown, Figure 7 This is Example 2 of the principle block diagram of LNG-RG and LAES in the embodiments of the present invention, which is in Figure 1 Based on the principle block diagram example one, the cold energy involved is divided into deep cold energy and shallow cold energy. Specifically,

[0098] like Figure 8 As shown, Figure 8 This is Example 2 of the first coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention. This coupling condition is based on Figure 7 Example 2 of the principle block diagram shown;

[0099] For the first coupling condition, the shallow cold energy generated by the LNG-RG system and stored in the LAES system, as well as the deep cold energy generated by the LNG-RG system and stored in the LAES system, can be sequentially output to the main gas along the flow direction of the main gas in the LAES system under the charging condition.

[0100] Furthermore, under the first coupling condition, the shallow cold energy generated by the LNG-RG system and the shallow cold energy 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, as well as 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 the deep cold energy 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.

[0101] Specifically, by supplying shallowly cooled energy to the main gas that has undergone air purification but has not undergone one or more stages of compression, the shallowly cooled energy of the LNG-RG system can be fully utilized to first cool the main gas before compression in the LAES system. This allows for low-temperature compression of the main gas during subsequent compression processes, reducing the electricity cost of the LAES system during charging. Furthermore, purifying the main gas before cooling removes dust, moisture, and carbon dioxide from the incoming ambient air, preventing water and carbon dioxide from condensing and crystallizing after cooling, which could cause pipe blockage and damage.

[0102] In existing LAES systems, the compression heat energy of the main gas after being compressed by the compressor unit is usually stored in a heat storage tank for heat recovery and is used 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 providing heat energy from an external heat source.

[0103] The shallow cold energy is directly exchanged with the main gas that has undergone one or more stages of compression but has not absorbed deep cold energy. In other words, the shallow cold energy is directly exchanged with the main gas that has compression heat energy. This fully utilizes 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.

[0104] Preferably, when using a compressor unit to perform multi-stage compression of the main gas, shallow cold energy can be used to exchange cold energy after each stage of the compressor.

[0105] like Figure 9 As shown, Figure 9 This is Example 2 of the second coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention. This coupling condition is based on Figure 7 Example 2 of the principle block diagram shown;

[0106] For the second coupling condition, the shallow and deep cold energy of the LNG-RG system can be output to the LAES system for independent storage.

[0107] In this embodiment, one cold storage device in the LAES system stores shallow cold energy separately, while another cold storage device stores deep cold energy separately.

[0108] like Figure 10 As shown, Figure 10 This is Example 2 of the third coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention. This coupling condition is based on Figure 7 Example 2 of the principle block diagram shown;

[0109] For the third coupling condition, the shallow cryogenic energy and deep cryogenic energy of the LNG-RG and LAES systems can be output to the LAES system for independent storage. Specifically, the deep and shallow cryogenic energy generated during the LAES system's discharge condition can be sequentially obtained from the regasified main gas during the heating and expansion process of the liquefied main gas.

[0110] like Figure 11 As shown, Figure 11 This is Example 3 of the principle block diagram of LNG-RG and LAES in the embodiments of the present invention, which is in Figure 7 Based on the principle block diagram example two, the recovery and utilization of ultracold energy has been added.

[0111] Specifically, in some embodiments, the coupling method of LNG-RG and LAES in the embodiments of the present invention may further include: when the LAES system is in charging condition, outputting the ultracold energy of the reflux main gas generated in the LAES system charging condition to the main gas that has absorbed cryogenic energy but has not been expanded and liquefied; wherein, the quality of the ultracold energy is higher than that of the cryogenic energy.

[0112] Specifically, the recovery and release of ultracold energy from the return main gas can be achieved by using heat exchangers or cold storage devices that are simultaneously connected to both the main gas liquefaction path and the return main gas path.

[0113] like Figure 12 As shown, Figure 12 This is Example 2 of the fifth coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention. This coupling condition is based on Figure 7 Example 2 of the principle block diagram shown;

[0114] For the fifth coupling condition, the LAES system, which cuts off the cold energy exchange with the LNG-RG system, in the charging condition, utilizes independently stored shallow and deep cold energy, which is sequentially output to the main gas along the flow direction of the main gas in the charging condition; while in the discharging condition, deep and shallow cold energy are sequentially obtained from the regasified main gas during the heating and expansion process of the liquefied main gas along the air regasification direction and stored independently.

[0115] In this embodiment of the invention, natural gas in the LNG-RG system's liquefied natural gas regasification path is used as a cold energy carrier for direct cold energy exchange in the LAES system; or, other heat exchange media are used as cold energy carriers for indirect cold energy exchange with the LAES system. Using natural gas in the LNG-RG system's liquefied natural gas regasification path as a cold energy carrier for cold energy exchange with the main gas means exchanging cold energy between the natural gas and the main gas in the same heat exchanger. Using other heat exchange media as a cold energy carrier for cold energy exchange with the main gas means adding an additional heat exchange medium between the natural gas and the main gas. This heat exchange medium transfers the cold energy of the natural gas to the main gas for liquefaction and transfers the heat energy of the main gas to the natural gas for regasification.

[0116] Preferably, in the embodiments of the present invention, the LNG-RG system and the LAES system can use other heat exchange media as cold energy carriers to exchange cold energy with the main gas.

[0117] In some embodiments, the LAES system's own cryogenic storage equipment may include: a shallow cryogenic tank (shallow cryogenic storage device) for storing and releasing shallow cryogenic energy, and a deep cryogenic tank (deep cryogenic storage device) for storing and releasing deep cryogenic energy; wherein, the hot end temperature of the shallow cryogenic tank is between ambient temperature and 0 degrees Celsius but not lower than 0 degrees Celsius, and its cold end temperature is the shallow cryogenic temperature; the hot end temperature of the deep cryogenic tank is the shallow cryogenic temperature, and its cold end temperature is the liquid-gas phase change temperature during LNG regasification. The selection of the shallow cryogenic temperature is determined based on the LAES system operating parameters and the actual low-temperature operation performance and parameters of the compressor.

[0118] 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.

[0119] To facilitate a quick understanding of the main concepts of this application by those skilled in the art, an example of a coupling system between LNG-RG and LAES is also disclosed in the embodiments of this invention, such as... Figure 13 As shown, Figure 13 This is an example of a coupled system structure for LNG-RG and LAES in this invention embodiment; the coupled system includes: an LNG-RG system and an LAES system; the LNG-RG system includes: a cryogenic natural gas heat exchanger HX-NG1 and a shallow-cold natural gas heat exchanger HX-NG2 sequentially connected in the LNG regasification path along the direction of LNG regasification; the LAES system includes: an air purification device (not shown), a first shallow-cold charging heat exchanger HX-SC1, a compressor C, and a second air purification device (not shown) sequentially connected in the main gas liquefaction path along the direction of main gas liquefaction. Two components are included: a 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 main liquefied gas regasification direction, the following components are sequentially connected: liquid air storage tank LAD, cryogenic pump CP, deep-cold discharge heat exchanger HX-DC1, deep-cold discharge heat exchanger HX-DC2, external heat source, and expander E. The liquid air storage tank LAD on both the main gas liquefaction path and the main gas regasification path is the same. Additionally, shallow-cold tank SCD and deep-cold tank DCD are also included.

[0120] Among them, the shallow cold natural gas heat exchanger HX-NG2 and the first shallow cold charging heat exchanger HX-SC1 form a first shallow cold closed loop for cold energy exchange with the first shallow cold heat exchange medium; in the first shallow cold closed loop, the hot ends of the shallow cold natural gas heat exchanger HX-NG2 and the first shallow cold charging heat exchanger HX-SC1 are connected respectively.

[0121] Among them, the first shallow cold charging heat exchanger HX-SC1, the second shallow cold charging heat exchanger HX-SC2, the shallow cold tank SCD, and the shallow cold discharge heat exchanger HX-DC2 form a second shallow cold closed loop for cold energy exchange with the second shallow cold heat exchange medium; in the second shallow cold closed loop, the hot ends of the first shallow cold charging heat exchanger HX-SC1, the second shallow cold charging heat exchanger HX-SC2, the shallow cold tank SCD, and the shallow cold discharge heat exchanger HX-DC2 are connected respectively, and the cold ends are connected respectively.

[0122] 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 cold energy exchange with 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.

[0123] 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 cold energy exchange with a second cryogenic heat exchange medium; in the second cryogenic closed loop, the cryogenic charging heat exchanger HX-CB, the cryogenic tank DCD, and the cryogenic discharge heat exchanger HX-DC1 are connected at their hot ends and at their cold ends respectively.

[0124] In the embodiments of the present invention, the first shallow cooling heat exchange medium and the second shallow cooling heat exchange medium can be the same or different heat exchange media, as long as they maintain a stable fluid state within the defined temperature range of shallow cooling energy; preferably, the first shallow cooling heat exchange medium and the second shallow cooling heat exchange medium can be methanol; similarly, the first cryogenic heat exchange medium and the second cryogenic heat exchange medium can be the same or different heat exchange media, as long as they maintain a stable fluid state within the defined temperature range of cryogenic energy; preferably, the first cryogenic heat exchange medium and the second cryogenic heat exchange medium can be propane.

[0125] like Figure 14 As shown, Figure 14 This is Example 3 of the first coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention. This coupling condition is based on Figure 13 The structure shown is example one;

[0126] When the LNG-RG system is operating and the LAES system is in charging mode, the first shallow-cold heat exchange medium in the first shallow-cold closed loop circulates in the following direction: cold end of shallow-cold natural gas heat exchanger HX-NG2, cold end of first shallow-cold charging heat exchanger HX-SC1, hot end of first shallow-cold charging heat exchanger HX-SC1, and hot end of shallow-cold natural gas heat exchanger HX-NG2.

[0127] The second shallow-cold heat exchange medium in the second shallow-cold closed loop circulates in the following flow direction: hot end of the first shallow-cold charging heat exchanger HX-SC1, hot end of the shallow-cold tank SCD, cold end of the shallow-cold tank SCD, and cold end of the first shallow-cold charging heat exchanger HX-SC1; and circulates in the following flow direction: cold end of the shallow-cold tank SCD, cold end of the second shallow-cold charging heat exchanger HX-SC2, hot end of the second shallow-cold charging heat exchanger HX-SC2, and hot end of the shallow-cold tank SCD.

[0128] The first cryogenic heat exchange medium in the first cryogenic closed loop is kept circulating in the following direction: 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.

[0129] The second cryogenic heat exchange medium in the second cryogenic closed loop circulates in the following direction: the hot end of the cryogenic charging heat exchanger HX-CB, the hot end of the cryogenic tank DCD, the cold end of the cryogenic tank DCD, and the cold end of the cryogenic charging heat exchanger HX-CB.

[0130] In the LAES system charging mode, the main gas exchanges cold energy with the corresponding heat exchange medium in the first shallow cold charging heat exchanger HX-SC1, the second shallow cold charging heat exchanger HX-SC2, and the deep cold charging heat exchanger HX-CB.

[0131] like Figure 15 As shown, Figure 15 This is Example 3 of the second coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention. This coupling condition is based on Figure 13 The structure shown is example one;

[0132] When the LNG-RG system is running and the LAES system is in a static state, the first shallow-cold heat exchange medium in the first shallow-cold closed loop circulates in the following direction: cold end of shallow-cold natural gas heat exchanger HX-NG2, cold end of first shallow-cold charging heat exchanger HX-SC1, hot end of first shallow-cold charging heat exchanger HX-SC1, and hot end of shallow-cold natural gas heat exchanger HX-NG2.

[0133] The first cryogenic heat exchange medium in the first cryogenic closed loop is kept circulating in the following direction: 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.

[0134] The second shallow cold heat exchange medium in the second shallow cold closed loop circulates in the direction of the cold end of the first shallow cold charging heat exchanger HX-SC1, the cold end of the shallow cold tank SCD, the hot end of the shallow cold tank SCD, and the hot end of the first shallow cold charging heat exchanger HX-SC1, to replenish the shallow cold energy of the shallow cold tank SCD.

[0135] The second cryogenic heat exchange medium in the second cryogenic closed loop circulates in the 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, replenishing the cryogenic energy of the cryogenic tank DCD.

[0136] like Figure 16 As shown, Figure 16 This is Example 3 of the third coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention. This coupling condition is based on Figure 13 The structure shown is example one;

[0137] When the LNG-RG system is operating and the LAES system is in discharge mode, the first shallow-cold heat exchange medium in the first shallow-cold closed loop circulates in the following direction: cold end of shallow-cold natural gas heat exchanger HX-NG2, cold end of first shallow-cold charging heat exchanger HX-SC1, hot end of first shallow-cold charging heat exchanger HX-SC1, and hot end of shallow-cold natural gas heat exchanger HX-NG2.

[0138] The first cryogenic heat exchange medium in the first cryogenic closed loop is kept circulating in the following direction: 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.

[0139] The second shallow-cold heat exchange medium in the second shallow-cold closed loop circulates in the following flow direction: cold end of the first shallow-cold charging heat exchanger HX-SC1, cold end of the shallow-cold tank SCD, hot end of the shallow-cold tank SCD, and hot end of the first shallow-cold charging heat exchanger HX-SC1; and circulates in the following flow direction: cold end of the shallow-cold discharge heat exchanger HX-DC2, cold end of the shallow-cold tank SCD, hot end of the shallow-cold tank SCD, and hot end of the shallow-cold discharge heat exchanger HX-DC2, to replenish shallow-cold energy to the shallow-cold tank SCD.

[0140] The second cryogenic heat exchange medium in the second cryogenic closed loop circulates in the following flow direction: 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 in the following flow direction: 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 to the cryogenic tank DCD.

[0141] In the LAES system under discharge conditions, the liquefied main gas exchanges cold energy with the corresponding heat exchange medium in the cryogenic discharge heat exchanger HX-DC1 and the shallow cryogenic discharge heat exchanger HX-DC2.

[0142] like Figure 17 As shown, Figure 17 This is Example 3 of the fourth coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention. This coupling condition is based on Figure 13 The structure shown is example one;

[0143] The LAES system may also include a gas phase passage running between the shallow-cold natural gas heat exchanger HX-NG2 and the deep-cold natural gas heat exchanger HX-NG1, 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 when there is excess cold energy in the cold storage tank, and to allow it to exchange cold energy with the LNG-RG system in the shallow-cold natural gas heat exchanger and the deep-cold natural gas heat exchanger in sequence.

[0144] by Figure 13 The fifth coupling condition, based on this, is the normal charging, resting, and discharging condition of the LAES system after the LNG-RG system and the LAES system are decoupled, which will not be elaborated here.

[0145] like Figure 18 As shown, Figure 18 This is a second example of the structure of the coupling system between the LNG-RG system and the LAES system in this embodiment of the invention. This embodiment adds an ultracold charging heat exchanger HX-UC to the structure example 13, so as to recover and consume ultracold energy under the charging condition of the LAES system, and further cool down the main gas after absorbing the deep cryogenic energy.

[0146] like Figure 19 As shown, an example of a coupling system between LNG-RG and LAES is also disclosed in this embodiment of the invention. Figure 19This is a third example of the structure of the LNG-RG and LAES coupling system in this embodiment of the invention; the coupling system includes: an LNG-RG system and an LAES system; the LNG-RG system includes: a cryogenic natural gas heat exchanger HX-NG1 and a shallow cryogenic natural gas heat exchanger HX-NG2 connected sequentially in the LNG regasification path along the direction of LNG regasification; the LAES system includes: an air purification device (not shown), a first shallow cryogenic tank SCD1, a compressor C, a second shallow cryogenic tank SCD2, a cryogenic tank DCD, a cryogenic expander CE, a liquid-gas separator LAS, and a liquid air storage tank LAD connected sequentially in the main gas liquefaction path along the direction of main gas regasification; and a liquid air storage tank LAD, a cryogenic pump CP, and a cryogenic tank connected sequentially in the main gas regasification path along the direction of LNG regasification. DCD, second shallow cooling tank SCD2, first expander, first shallow cooling tank SCD1, second expander; wherein, the liquid air storage tank LAD on the main gas liquefaction path and the liquefied main gas regasification path is the same; the main gas liquefaction path and the liquefied main gas path pass through the first shallow cooling tank SCD1, the second shallow cooling tank SCD2, and the deep cooling tank DCD, directly exchanging 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 cooling tank SCD1, the second shallow cooling tank SCD2, and the deep cooling tank DCD are the same path, but the air flow direction is opposite; wherein, not shown, an external heat source can be connected between the second shallow cooling tank SCD2 and the first expander E1, and between the first shallow cooling tank SCD1 and the second expander E2 along the liquefied main gas regasification path.

[0147] The shallow-cooled natural gas heat exchanger HX-NG2, the first shallow-cooled tank SCD1, and the second shallow-cooled tank SCD2 form a shallow-cooled closed loop for energy exchange using a shallow-cooled cooling medium; wherein, the hot ends of the shallow-cooled natural gas heat exchanger HX-NG2, the first shallow-cooled tank SCD1, and the second shallow-cooled tank SCD2 are connected separately, and the cold ends are connected separately.

[0148] A cryogenic closed loop is formed between the cryogenic natural gas heat exchanger HX-NG1 and the cryogenic tank DCD, where cold energy is exchanged using a cryogenic heat exchange medium. In the cryogenic closed loop, the hot ends of the cryogenic natural gas heat exchanger HX-NG1 and the cryogenic tank DCD are connected separately, and the cold ends are connected separately.

[0149] Under the first, second, and third coupling conditions, the shallow-cold heat exchange medium circulates in the following flow direction: the cold end of the shallow-cold 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-cold natural gas heat exchanger; and the shallow-cold heat exchange medium circulates in the following flow direction: the cold end of the shallow-cold 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-cold natural gas heat exchanger. The deep-cold heat exchange medium circulates in the following flow direction: the cold end of the deep-cold natural gas heat exchanger, the cold end of the deep-cold tank, the hot end of the deep-cold tank, and the hot end of the deep-cold natural gas heat exchanger.

[0150] Figure 20 This is Example 5 of the first coupling operation condition between the LNG-RG system and the LAES system in this embodiment of the invention, applicable to... Figure 19 Example 3 of the coupled system structure is shown. First coupling condition: When the LNG-RG system is running and the LAES system is in 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 in the charging condition of the LAES system, realizing the regasification of LNG and the liquefaction of the main gas.

[0151] Figure 21 This is Example 4 of the second coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention; applicable to Figure 19 Example 3 of the coupled system structure is shown. 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 LNG regasification and cold storage of the LAES system.

[0152] Figure 22 This is Example 4 of the third coupling condition between the LNG-RG system and the LAES system in this embodiment of the invention, applicable to... Figure 19 Example 3 of the coupled system structure is shown. When the LNG-RG system is operating and the LAES system is in discharge mode, the cold energy generated by the LNG-RG system and the cold energy generated by the LAES system in discharge mode are jointly output to the LAES system for storage, realizing the regasification of LNG, the regasification of the liquefied main gas, and the cold storage of the LAES system.

[0153] like Figure 20 In the three coupled operating conditions shown in 21 and 22, the cold storage and cold energy exchange equipment are combined into one, including the combination of shallow cold storage equipment and shallow cold energy exchange equipment, and the combination of deep cold energy storage equipment and deep cold energy exchange equipment; 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.

[0154] The fourth coupling condition can be referred to Figure 17 The examples shown will not be repeated here.

[0155] Under the fifth coupling condition, both the shallow cold closed loop and the deep cold closed loop are disconnected, and the shallow cold heat exchange medium and the deep cold heat exchange medium do not circulate.

[0156] like Figure 23 As shown, Figure 23 This is Example 4 of the coupling system structure of LNG-RG and LAES in the embodiments of the present invention; this embodiment is... Figure 19Based on the structural example three, an ultracold tank UCD is added, thereby recovering and consuming ultracold energy during the charging operation of the LAES system, and further cooling the main gas that has absorbed the deep cryogenic energy.

[0157] Those skilled in the art should understand that the coupling system in the embodiments of the present invention may include several valve bodies to control the switching between various paths, cycles, and loops (between various coupling conditions) in the coupling system; wherein, using valve bodies to control the on / off state of pipelines is a conventional technique in the art. In addition, through the illustrations in the coupling condition examples in the embodiments of the present invention, solid lines represent connection (enabled) and dashed lines represent blockage (disabled), which can also clearly indicate the on / off state under various conditions, and the present invention will not elaborate on this further.

[0158] In this embodiment of the invention, the shallow cryogenic tank (SCD) and deep cryogenic tank (DCD) in the LAES system can adopt one or more tank structures connected in series or parallel (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 cryogenic tanks (SCD) and deep cryogenic tanks (DCD) in the LAES system can be configured according to the cold release requirements, and the system can consist of multiple shallow and deep cryogenic tanks to meet the flexible coupling needs of multiple operating conditions of LNG-RG and LAES. In these implementation examples, the SCD and DCD are solid packed beds that use a fluid heat exchange medium for cold energy exchange.

[0159] Another object of the present invention is to provide a coupling system for LNG-RG and LAES to solve the problems existing in the prior art; such as Figure 24 As shown, Figure 24 This is a system block diagram example of the LNG-RG and LAES coupling system 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 under the charging condition of the LAES system when the LNG-RG system is running and the LAES system is in the charging condition, thereby realizing the regasification of LNG and the liquefaction of the main gas; a second coupling control module 130 for outputting 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 the quiescent condition, thereby realizing the regasification of LNG and the cold storage of the LAES system; and a third coupling control module 140 for outputting the cold energy generated by the LNG-RG system and the cold energy generated under the discharging condition of the LAES system to the LAES system for storage when the LNG-RG system is running and the LAES system is in the discharging condition, thereby realizing the regasification of LNG, the regasification of the liquefied main gas, and the cold storage of the LAES system.

[0160] In some embodiments, the coupling system further includes: a fourth coupling control module 150, used to bypass the LAES system and output the cold energy generated by the LNG-RG system to the ambient air when the LNG-RG system is running and the LAES system is shut down or has excess cold storage, thereby realizing the regasification of LNG.

[0161] In some embodiments, the coupling system further includes a fifth coupling control module 160, 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.

[0162] In some embodiments, the coupling system further includes a cold storage tank for storing the cold energy of the LNG-RG system and the LAES system, wherein the main gas liquefaction path and the liquid main gas regasification path of the LAES system are arranged outside the cold storage tank.

[0163] In some embodiments, the coupling system further includes a cold storage tank for storing the cold energy of the LNG-RG system and the LAES system, wherein 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; within the cold storage tank, the main gas liquefaction path and the liquid main gas regasification path are the same path but with opposite airflow directions.

[0164] In some embodiments, natural gas in the LNG-RG system's liquefied natural gas regasification path is used as a cold energy carrier for direct cold energy exchange in the LAES system; or, other heat exchange media are used as cold energy carriers for indirect cold energy exchange with the LAES system.

[0165] In some embodiments, cold energy is divided into deep cold energy and shallow cold energy according to quality.

[0166] In some embodiments, the first coupling control module 120 is used to sequentially output 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, to the main gas along the flow direction of the main gas under charging conditions.

[0167] In some embodiments, the second coupling control module 130 is used to output the deep cryogenic energy and shallow cryogenic energy of the LNG-RG system to the LAES system for independent storage.

[0168] In some embodiments, the third coupling control module 140 is used to output the shallow cold energy and the deep cold energy under the discharge conditions of the LNG-RG system and the LAES system to the LAES system for independent storage.

[0169] In some embodiments, the LAES system includes: a shallow cryogenic tank for storing and releasing shallow cryogenic energy, and a deep cryogenic tank for storing and releasing deep cryogenic energy; wherein the hot end temperature of the shallow cryogenic 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 cryogenic temperature; the hot end temperature of the deep cryogenic tank is the shallow cryogenic temperature, and its cold end temperature is the liquid-gas phase change temperature during LNG regasification.

[0170] In some embodiments, the first coupling module 120 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 deep cold energy; and to 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 shallow cold energy but has not been expanded and liquefied.

[0171] In some embodiments, the first coupling module 120 is further configured to output the ultracold energy of the reflux main gas generated during the charging operation 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 ultracold energy is higher than that of the cryogenic energy.

[0172] In some embodiments, the deep cryogenic energy and shallow cryogenic energy generated under the discharge conditions of the LAES system are successively obtained from the regasified main gas during the heating and expansion process of the liquefied main gas.

[0173] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions 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 for LNG-RG and LAES, characterized in that, include: When the LNG-RG system is operating and the LAES system is in charging mode, 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 mode of the LAES system to realize 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, thereby realizing the regasification of LNG and the cold storage of the LAES system. When the LNG-RG system is operating and the LAES system is in discharge mode, the cold energy generated by the LNG-RG system and the cold energy generated by the LAES system in discharge mode are jointly output to the LAES system for storage, realizing LNG regasification, liquefied main gas regasification, and cold storage of the LAES system; wherein, the cold energy is divided into deep cold energy and shallow cold energy according to quality; the process of 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 mode of the LAES system when the LNG-RG system is operating and the LAES system is in charging mode, realizing LNG regasification and main gas liquefaction, includes: outputting the shallow cold energy and the deep cold energy of the LNG-RG system and LAES system sequentially to the main gas along the flow direction of the main gas in the charging mode; the process of outputting the shallow cold energy and the deep cold energy of the LNG-RG system and LAES system sequentially to the main gas along the flow direction of the main gas in the charging mode includes: The process of jointly outputting the shallow cold energy from 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; jointly outputting the deep cold energy from the LNG-RG system and the LAES system to the main gas in the LAES system that has absorbed shallow cold energy but has not undergone expansion and liquefaction; when the LNG-RG system is operating and the LAES system is in a static state, the process of outputting the cold energy generated by the LNG-RG system to the LAES system for storage, thereby realizing LNG regasification and cold storage in the LAES system, includes: outputting the deep cold energy and shallow cold energy from the LNG-RG system to the LAES system for independent storage; when the LNG-RG system is operating and the LAES system is in a discharge state, the process of jointly outputting the cold energy generated by the LNG-RG system and the cold energy generated by the LAES system in the discharge state to the LAES system for storage, thereby realizing LNG regasification, regasification of the liquefied main gas, and cold storage in the LAES system, includes: The shallow cold energy and deep cold energy under the discharge conditions of the LNG-RG system and LAES system are respectively output to the LAES system for independent storage.

2. The coupling method according to claim 1, characterized in that, Also includes: When the LNG-RG system is operating and the LAES system is shut down or has excess cold storage, the cold energy generated by the LNG-RG system is bypassed by the LAES system and output to the ambient air, thus realizing the regasification of LNG.

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

4. The coupling method according to claim 1, characterized in that, Natural gas from the LNG-RG system regasification process can be used as a cold energy carrier for direct cold energy exchange in the LAES system; or, other heat exchange media can be used as cold energy carriers for indirect cold energy exchange with the LAES system.

5. The coupling method according to claim 1, characterized in that, The LAES system includes: a shallow cryogenic tank for storing and releasing shallow cryogenic energy, and a deep cryogenic tank for storing and releasing deep cryogenic energy; wherein, the hot end temperature of the shallow cryogenic 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 cryogenic temperature; the hot end temperature of the deep cryogenic tank is the shallow cryogenic temperature, and its cold end temperature is the liquid-gas phase change temperature during LNG regasification.

6. The coupling method according to claim 1, characterized in that, Also includes: When the LAES system is charging, the ultracold energy of the reflux main gas generated during the charging process is output to the main gas that has absorbed cryogenic energy but has not been expanded and liquefied; wherein, the quality of the ultracold energy is higher than that of the cryogenic energy.

7. The coupling method according to claim 1, characterized in that, The deep and shallow cold energy generated under the discharge conditions of the LAES system are successively obtained from the regasified main gas during the heating and expansion process of the liquefied main gas.

8. A coupling system for LNG-RG and LAES, characterized in that, include: The dynamic monitoring module is used to monitor the current status of the LNG-RG system and the LAES system; The first coupling control module is used to output the cold energy generated by the LNG-RG system and the cold energy stored in the LAES system to the main gas under the charging condition of the LAES system when the LNG-RG system is running and the LAES system is in charging condition, so as to realize the regasification of LNG and the 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 state, so as to realize 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, so as to realize the regasification of LNG, the regasification of liquefied main gas and the cold storage of the LAES system. The coupling system divides cold energy into deep cold energy and shallow cold energy according to their quality. The first coupling control module is used to sequentially output the shallow cooling energy 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 charging conditions; the first coupling control module is further used to output the shallow cooling 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 cooling energy; and to output the deep cooling energy of the LNG-RG system and the LAES system to the main gas in the LAES system that has absorbed shallow cooling energy but has not undergone expansion and liquefaction. The second coupling control module is used to output the deep cryogenic energy and shallow cryogenic energy of the LNG-RG system to the LAES system for independent storage, respectively; The third coupling control module is used to output the shallow cold energy and the deep cold energy under the discharge conditions of the LNG-RG system and the LAES system to the LAES system for independent storage.

9. The coupling system according to claim 8, characterized in that, Also includes: The fourth coupling control module is used to bypass the LAES system and output the cold energy generated by the LNG-RG system to the ambient air when the LNG-RG system is running and the LAES system is shut down or has excess cold storage, thereby realizing the regasification of LNG.

10. The coupling system according to claim 8, 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.

11. The coupling system according to claim 8, 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 are arranged outside the cold storage tank.

12. The coupling system according to claim 8, characterized in that, Also includes: The 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 direction is opposite.

13. The coupling system according to claim 8, characterized in that, Natural gas from the LNG-RG system's liquefied natural gas regasification path can be used as a cold energy carrier for direct cold energy exchange within the LAES system; alternatively, other heat exchange media can be used as cold energy carriers for indirect cold energy exchange with the LAES system.

14. The coupling system according to claim 8, characterized in that, The LAES system includes: a shallow cryogenic tank for storing and releasing shallow cryogenic energy, and a deep cryogenic tank for storing and releasing deep cryogenic energy; wherein, the hot end temperature of the shallow cryogenic 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 cryogenic temperature; the hot end temperature of the deep cryogenic tank is the shallow cryogenic temperature, and its cold end temperature is the liquid-gas phase change temperature during LNG regasification.

15. The coupling system according to claim 8, characterized in that, The first coupling control module is also used to output the ultracold energy of the return main gas generated during the charging operation 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 ultracold energy is higher than that of the cryogenic energy.

16. The coupling system according to claim 8, characterized in that, The deep and shallow cold energy generated under the discharge conditions of the LAES system are successively obtained from the regasified main gas during the heating and expansion process of the liquefied main gas.

Images