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

Abstract

The application discloses a liquefied natural gas regasification and liquid air energy storage coupling system, and relates to the technical field of large-scale energy storage.The coupling system comprises an LNG-RG system and a LAES system.The LNG-RG system comprises a natural gas heat exchanger connected to a liquefied natural gas regasification path.The LAES system comprises a charging heat exchanger connected to a main gas liquefaction path, a discharging heat exchanger connected to a liquefied main gas regasification path, and a cold storage tank.A first heat exchange cycle is formed between the natural gas heat exchanger and the charging heat exchanger to exchange cold energy with a first heat exchange medium.A second heat exchange cycle is formed between the charging heat exchanger, the cold storage tank and the discharging heat exchanger to exchange cold energy with a second heat exchange medium.In the first heat exchange cycle, the natural gas heat exchanger and the charging heat exchanger are connected at the hot end and the cold end, respectively.In the second heat exchange cycle, the charging heat exchanger, the cold storage tank and the discharging heat exchanger are connected at the hot end and the cold end, respectively.In the embodiment, the LAES system can be in any one of the charging condition, the static condition and the discharging condition, and the cold energy and the heat energy can be effectively coupled and utilized between the LAES system and the LNG-RG system, the coupling system is improved, and the effective coupling utilization rate of the cold energy and the heat energy between the systems is improved.

Description

Technical Field

[0001] This invention belongs to the field of large-scale energy storage technology, and in particular relates to a coupled system of 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 system for liquefied natural gas regasification and liquid air energy storage, in order to solve the problem that the coupling system between the LAES system and the LNG-RG system in the prior art is imperfect and the effective coupling utilization rate of cold energy and heat energy between the systems is low.

[0006] In some illustrative embodiments, the LNG-RG and LAES coupling system includes an LNG-RG system and an LAES system; the LNG-RG system includes a natural gas heat exchanger connected to the liquefied natural gas regasification path; the LAES system includes a cold storage tank, a charging heat exchanger connected to the main gas liquefaction path, and a discharging heat exchanger connected to the liquefied main gas regasification path.

[0007] The natural gas heat exchanger and the charging heat exchanger form a first heat exchange cycle for cold energy exchange using a first heat exchange medium; the charging heat exchanger, the cold storage tank, and the discharge heat exchanger form a second heat exchange cycle for cold energy exchange using a second heat exchange medium.

[0008] In the first heat exchange cycle, the hot ends of the natural gas heat exchanger and the charging heat exchanger are connected separately, and the cold ends are connected separately; in the second heat exchange cycle, the hot ends of the charging heat exchanger, the cold storage tank, and the discharge heat exchanger are connected separately, and the cold ends are connected separately.

[0009] In some optional embodiments, when the LNG-RG system is operating and the LAES system is in charging condition, quiescent condition, discharging condition, or condition change, the first heat exchange medium in the first heat exchange cycle maintains a circulation direction of the cold end of the natural gas heat exchanger, the cold end of the charging heat exchanger, the hot end of the charging heat exchanger, and the hot end of the natural gas heat exchanger; the second heat exchange medium in the second heat exchange cycle exchanges cold energy with the first heat exchange medium in the charging heat exchanger.

[0010] In some optional embodiments, when the LNG-RG system is shut down and the LAES system is in charging condition, the second heat exchange medium in the second heat exchange cycle circulates in the direction of the cold end of the cold storage tank, the cold end of the charging heat exchanger, the hot end of the charging heat exchanger, and the hot end of the cold storage tank; the main gas under the charging condition of the LAES system exchanges cold energy with the second heat exchange medium in the charging heat exchanger.

[0011] In some optional embodiments, when the LNG-RG system is shut down and the LAES system is in discharge mode, the second heat exchange medium in the second heat exchange cycle circulates in the direction of the cold end of the discharge heat exchanger, the cold end of the cold storage tank, the hot end of the cold storage tank, and the hot end of the discharge heat exchanger; the liquefied main gas under the discharge mode of the LAES system exchanges cold energy with the second heat exchange medium in the discharge heat exchanger.

[0012] In some optional embodiments, the cold storage tank includes: a shallow cold tank for storing and releasing shallow cold energy, and a deep cold tank for storing and releasing deep cold energy; the natural gas heat exchanger includes: a deep cold natural gas heat exchanger and a shallow cold natural gas heat exchanger arranged sequentially along the liquefied natural gas regasification direction on the liquefied natural gas regasification path; the charging heat exchanger includes: a shallow cold charging heat exchanger and a deep cold charging heat exchanger arranged sequentially along the main gas liquefaction direction on the main gas liquefaction path; the discharge heat exchanger includes: a deep cold discharge heat exchanger and a shallow cold discharge heat exchanger arranged sequentially along the main gas regasification direction on the liquefied main gas regasification path; the first heat exchange medium includes: a first shallow cold heat exchange medium and a first deep cold heat exchange medium; the second heat exchange medium includes: a second shallow cold heat exchange medium and a second deep cold heat exchange medium.

[0013] In some optional embodiments, the first heat exchange cycle includes: a first shallow-cold closed loop for cold energy exchange between the shallow-cold natural gas heat exchanger and the shallow-cold charging heat exchanger using a first shallow-cold heat exchange medium; and a first deep-cold closed loop for cold energy exchange between the deep-cold natural gas heat exchanger and the deep-cold charging heat exchanger using a first deep-cold heat exchange medium; wherein, in the first shallow-cold closed loop, the hot ends of the shallow-cold natural gas heat exchanger and the shallow-cold charging heat exchanger are respectively connected, and the cold ends are respectively connected; in the first deep-cold closed loop, the hot ends of the deep-cold natural gas heat exchanger and the deep-cold charging heat exchanger are respectively connected, and the cold ends are respectively connected.

[0014] In some optional embodiments, the second heat exchange cycle includes: a second shallow-cold closed loop for cold energy exchange between the shallow-cold charging heat exchanger, the shallow-cold tank, and the shallow-cold discharging heat exchanger using a second shallow-cold heat exchange medium; and a second deep-cold closed loop for cold energy exchange between the deep-cold charging heat exchanger, the deep-cold tank, and the deep-cold discharging heat exchanger using a second deep-cold heat exchange medium; wherein, in the second shallow-cold closed loop, the hot ends of the shallow-cold charging heat exchanger, the shallow-cold tank, and the shallow-cold discharging heat exchanger are respectively connected, and the cold ends are respectively connected; in the second deep-cold closed loop, the hot ends of the deep-cold charging heat exchanger, the deep-cold tank, and the deep-cold discharging heat exchanger are respectively connected, and the cold ends are respectively connected.

[0015] In some optional embodiments, the shallow-cold charging heat exchanger includes: a first shallow-cold charging heat exchanger and a second shallow-cold charging heat exchanger arranged sequentially along the main gas liquefaction direction on the main gas liquefaction path.

[0016] The shallow cold natural gas heat exchanger and the first shallow cold charging heat exchanger form a first shallow cold closed loop for cold energy exchange with a first shallow cold heat exchange medium; the first shallow cold charging heat exchanger, the second shallow cold charging heat exchanger, the shallow cold tank and the shallow cold discharge heat exchanger form a second shallow cold closed loop for cold energy exchange with a second shallow cold heat exchange medium.

[0017] In the first shallow-cold closed loop, the hot ends of the shallow-cold natural gas heat exchanger and the first shallow-cold charging heat exchanger are connected to each other, and the cold ends are connected to each other; in the second shallow-cold closed loop, the hot ends of the first shallow-cold charging heat exchanger, the second shallow-cold charging heat exchanger, the shallow-cold tank, and the shallow-cold discharge heat exchanger are connected to each other, and the cold ends are connected to each other.

[0018] In some optional embodiments, when the LNG-RG system is operating and the LAES system is in charging, quiescent, discharging, or changing condition, the first cryogenic heat exchange medium in the first cryogenic closed loop maintains a circulation in the direction of the cold end of the cryogenic natural gas heat exchanger, the cold end of the cryogenic charging heat exchanger, the hot end of the cryogenic charging heat exchanger, and the hot end of the cryogenic natural gas heat exchanger; simultaneously, the first shallow cryogenic heat exchange medium in the first shallow cryogenic closed loop maintains a circulation in the direction of the cold end of the shallow cryogenic natural gas heat exchanger, the cold end of the first shallow cryogenic charging heat exchanger, the hot end of the first shallow cryogenic charging heat exchanger, and the hot end of the shallow cryogenic natural gas heat exchanger.

[0019] In some optional embodiments, when the LNG-RG system is operating and the LAES system is in charging condition, 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, hot end of the shallow-cold tank, cold end of the shallow-cold tank, and cold end of the first shallow-cold charging heat exchanger; and in the following flow direction: cold end of the shallow-cold tank, cold end of the second shallow-cold charging heat exchanger, hot end of the second shallow-cold charging heat exchanger, and hot end of the cold storage tank; simultaneously, the second deep-cold heat exchange medium in the second deep-cold closed loop circulates in the following flow direction: hot end of the deep-cold charging heat exchanger, hot end of the deep-cold tank, cold end of the deep-cold tank, and cold end of the deep-cold charging heat exchanger; the main gas under the LAES system charging condition sequentially exchanges cold energy with the corresponding heat exchange medium in the first shallow-cold charging heat exchanger, the second shallow-cold charging heat exchanger, and the deep-cold charging heat exchanger.

[0020] In some optional embodiments, when the LNG-RG system is operating and the LAES system is in a quiescent state, 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, the cold end of the shallow-cold tank, the hot end of the shallow-cold tank, and the hot end of the first shallow-cold charging heat exchanger, replenishing the shallow-cold tank with shallow-cold energy; simultaneously, the second deep-cold heat exchange medium in the second deep-cold closed loop circulates in the direction of the cold end of the deep-cold charging 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 charger, replenishing the deep-cold tank with deep-cold energy.

[0021] In some optional embodiments, when the LNG-RG system is operating and the LAES system is in discharge mode, 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, the cold end of the shallow-cold tank, the hot end of the shallow-cold tank, and the hot end of the first shallow-cold charging heat exchanger; and circulates in the direction of the cold end of the shallow-cold discharge heat exchanger, the cold end of the shallow-cold tank, the hot end of the shallow-cold tank, and the hot end of the shallow-cold discharge heat exchanger, to replenish shallow-cold energy to the shallow-cold tank; simultaneously, the second deep-cold heat exchange medium in the second deep-cold closed loop circulates in the direction of the cold end of the deep-cold charging 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 charging heat exchanger; and circulates in the direction of the cold end of the deep-cold discharge 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 discharge heat exchanger, to replenish deep-cold energy to the deep-cold tank;

[0022] 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 and the shallow cryogenic discharge heat exchanger in sequence.

[0023] In some optional embodiments, the LAES system further includes: a compressor, a cryogenic expander, a liquid-gas separator, and a liquid air storage tank arranged sequentially along the main gas liquefaction path; wherein, the first shallow cryogenic charging heat exchanger is located before the main gas inlet of the compressor, the second shallow cryogenic charging heat exchanger is located between the compressor and the cryogenic expander; and the deep cryogenic charging heat exchanger is located between the second shallow cryogenic charging heat exchanger and the cryogenic expander.

[0024] In some optional embodiments, the LAES system further includes: an ultracold charging heat exchanger simultaneously connected to the main gas liquefaction path and the return main gas path; wherein the ultracold charging heat exchanger is located after the cryogenic charging heat exchanger along the main gas liquefaction direction on the main gas liquefaction path, and is located before the cryogenic charging heat exchanger along the return main gas direction on the return main gas path, for the cascade recovery and use of ultracold and cryogenic energy from the return main gas.

[0025] In some optional embodiments, the coupling system further includes a gas phase passage running through the shallow-cold natural gas heat exchanger and the deep-cold natural gas heat exchanger, for conveying purified ambient air through the gas phase passage when the LNG-RG system is operating and the LAES system is shut down or the cold storage tank has excess cold energy, and allowing it to exchange cold energy with the LNG-RG system sequentially in the shallow-cold natural gas heat exchanger and the deep-cold natural gas heat exchanger.

[0026] Compared with the prior art, this application has the following advantages:

[0027] This invention not only couples the LNG-RG system's operating conditions with the LAES system's charging conditions, but also separately couples the LNG-RG system's operating conditions with the LAES system's quiescent and discharging conditions. Regardless of whether the LAES system is in charging, quiescent, or discharging mode, effective coupling and utilization of cold and heat energy between it and the LNG-RG system can be achieved, thus improving the coupling system and enhancing the effective coupling and utilization rate of cold and heat energy between the systems. Simultaneously, it ensures the continuous operation of the LNG-RG system under various coupled operating conditions with the LAES system, allowing either the LAES system or the LNG-RG system to switch operating conditions according to its actual needs. Attached Figure Description

[0028] Figure 1 This is a structural example of the coupled system of the LNG-RG system and the LAES system in this embodiment of the invention;

[0029] Figure 2 This is an example of the first coupling condition of the coupling system in the embodiments of the present invention;

[0030] Figure 3 This is an example of the second coupling condition of the coupling system in this embodiment of the invention;

[0031] Figure 4 This is an example of the third coupling condition of the coupling system in the embodiments of the present invention;

[0032] Figure 5 This is an example of the fourth coupling condition of the coupling system in the embodiments of the present invention;

[0033] Figure 6 This is an example of the fifth coupling condition of the coupling system in this embodiment of the invention;

[0034] Figure 7 This is the second example of the fifth coupling condition of the coupling system in this embodiment of the invention;

[0035] Figure 8This is a second example of the structure of the coupled system of the LNG-RG system and the LAES system in this invention embodiment;

[0036] Figure 9 This is a third example of the structure of the coupled system of the LNG-RG system and the LAES system in this invention embodiment;

[0037] Figure 10 This is Example 2 of the first coupling condition of the coupling system in the embodiments of the present invention;

[0038] Figure 11 This is a second example of the second coupling condition of the coupling system in this embodiment of the invention;

[0039] Figure 12 This is Example 2 of the third coupling condition of the coupling system in the embodiments of the present invention;

[0040] Figure 13 This is Example 3 of the first coupling condition of the coupling system in this embodiment of the invention;

[0041] Figure 14 This is the fourth example of the structure of the coupled system of the LNG-RG system and the LAES system in this embodiment of the invention;

[0042] Figure 15 This is Example 4 of the first coupling condition of the coupling system in this embodiment of the invention;

[0043] Figure 16 This is Example 2 of the fourth coupling condition of the coupling system in this embodiment of the invention;

[0044] Figure 17 This is the fifth example of the structure of the coupled system of the LNG-RG system and the LAES system in the embodiments of the present invention.

[0045] Figure label:

[0046] 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);

[0047] The heat exchangers include: HX-C (Heat Exchanger-Charge), HX-SC (Heat Exchanger-Shallow Cold), HX-CB (Heat Exchanger-Cold Box), HX-SC1 (Heat Exchanger-Shallow Cold 1), HX-SC2 (Heat Exchanger-Shallow Cold 2), HX-SC3 (Heat Exchanger-Shallow Cold 3), HX-SC4 (Heat Exchanger-Shallow Cold 4), and HX-UC (Heat Exchanger-Ultra Cold).

[0048] Cold storage tank CD (Cold Dewar), Shallow Cold Dewar SCD (Shallow Cold Dewar), First Shallow Cold Dewar SCD1 (Shallow Cold Dewar 1), Second Shallow Cold Dewar SCD2 (Shallow Cold Dewar 2), Deep Cold Dewar DCD (Deep Cold Dewar), First Deep Cold Dewar DCD1 (Deep Cold Dewar 1), Second Deep Cold Dewar DCD2 (Deep Cold Dewar 2);

[0049] 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).

[0050] Compressor C, primary compressor C1, secondary compressor C2, tertiary compressor C3, cryogenic expander CE, liquid air separator LAS, liquid air tank LAD, cryogenic pump CP, expander E. Detailed Implementation

[0051] 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.

[0052] 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.

[0053] Terminology Explanation:

[0054] 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).

[0055] 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 is converted into liquefied main gas by absorbing cold energy (and releasing heat energy) in the main gas liquefaction path, and the liquefied main gas is converted into regasified main gas by releasing cold energy (and absorbing heat energy) in the liquefied main gas regasification path.

[0056] 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.

[0057] This invention discloses a coupled system of liquefied natural gas regasification (LNG-RG) and liquid air energy storage (LAES), specifically, as follows: Figure 1 As shown, Figure 1 This is a structural example of the coupled system of the LNG-RG system and the LAES system in this embodiment of the invention;

[0058] The coupled system includes: an LNG-RG system and an LAES system; the LNG-RG system includes: a natural gas heat exchanger HX-NG connected to the liquefied natural gas regasification path; the LAES system includes: a charging heat exchanger HX-C connected to the main gas liquefaction path, a discharging heat exchanger HX-DC connected to the liquefied main gas regasification path, and a cold storage tank CD.

[0059] The natural gas heat exchanger HX-NG and the charging heat exchanger HX-C form a first heat exchange cycle in which cold energy is exchanged using a first heat exchange medium; the charging heat exchanger HX-C, the cold storage tank CD and the discharge heat exchanger HX-DC form a second heat exchange cycle in which cold energy is exchanged using a second heat exchange medium.

[0060] In the first heat exchange cycle, the hot ends of the natural gas heat exchanger HX-NG and the charging heat exchanger HX-C are connected separately, and the cold ends are connected separately. In the second heat exchange cycle, the hot ends of the charging heat exchanger HX-C, the cold storage tank CD, and the discharge heat exchanger HX-DC are connected separately, and the cold ends are connected separately.

[0061] In some embodiments, the main gas liquefaction path of the LAES system includes: an air purification device (not shown), a compressor C, a cryogenic expander CE, a liquid-gas separator LAS, and a liquid air storage tank LAD, connected in sequence; wherein, a charging heat exchanger HX-C may be located between the compressor C and the cryogenic expander CE. The liquefied main gas regasification path of the LAES system includes: a liquid air storage tank LAD, a cryogenic pump CP, and an expander E, connected in sequence; wherein, a discharge heat exchanger HX-DC may be located between the cryogenic pump CP and the expander E. The liquid air storage tank LAD on both the main gas liquefaction path and the liquefied main gas regasification path is the same.

[0062] 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.

[0063] like Figure 2 As shown, Figure 2 This is an example of the first coupling condition of the coupling system in this embodiment of the invention, applicable to... Figure 1 Example 1 of the structure of a coupled system is shown;

[0064] In the 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, so as to realize the regasification of LNG and the liquefaction of the main gas.

[0065] Specifically, since the charging heat exchanger HX-C is connected to the main gas liquefaction path of the LAES system, in the first heat exchange cycle, the cold energy generated by LNG regasification during the operation of the LNG-RG system can be transferred to the main gas entering the charging heat exchanger HX-C under the charging condition of the LAES system through the first heat exchange medium, and the heat energy of the main gas entering the charging heat exchanger HX-C under the charging condition of the LAES system can be transferred to the LNG-RG system. At the same time, in the second heat exchange cycle, the cold energy stored in the cold storage tank CD of the LAES system can be transferred to the main gas entering the charging heat exchanger HX-C under the charging condition of the LAES system through the second heat exchange medium, and the heat energy of the main gas entering the charging heat exchanger HX-C under the charging condition of the LAES system can be transferred to the cold storage tank CD of the LAES system itself. This achieves the effect of outputting the cold energy generated by the operation of the LNG-RG system and the cold energy stored in the LAES system itself to the main gas under the charging condition of the LAES system, realizing the regasification of LNG and the liquefaction of the main gas.

[0066] Furthermore, at this time, the first heat exchange medium in the first heat exchange cycle circulates in the following direction: cold end of natural gas heat exchanger HX-NG, cold end of charging heat exchanger HX-C, hot end of charging heat exchanger HX-C, and hot end of natural gas heat exchanger HX-NG; the second heat exchange medium in the second heat exchange cycle circulates in the following direction: cold end of cold storage tank CD, cold end of charging heat exchanger HX-C, hot end of charging heat exchanger HX-C, and hot end of cold storage tank CD.

[0067] like Figure 3 As shown, Figure 3 This is an example of the second coupling condition of the coupling system in this embodiment of the invention, applicable to... Figure 1 Example 1 of the structure of a coupled system is shown;

[0068] The second coupling operation mode is when the LNG-RG system is running and the LAES system is in a static operation mode, 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.

[0069] Specifically, in the first heat exchange cycle, the cold energy generated by the regasification of LNG during the operation of the LNG-RG system is transferred to the second heat exchange medium in the charging heat exchanger HX-C, which is in the second heat exchange cycle, through the first heat exchange medium. Then, the cold energy is transferred to the cold storage tank CD for storage through the second heat exchange medium in the second heat exchange cycle. Conversely, after transferring the cold energy to the cold storage tank CD, the second heat exchange medium, which loses its cold energy and thus heats up, transfers the heat energy to the first heat exchange medium in the first heat exchange cycle in the charging heat exchanger HX-C, thereby enabling the LNG in the LNG-RG system to absorb heat energy and achieve regasification.

[0070] Furthermore, at this time, the first heat exchange medium in the first heat exchange cycle circulates in the following direction: cold end of natural gas heat exchanger HX-NG, cold end of charging heat exchanger HX-C, hot end of charging heat exchanger HX-C, and hot end of natural gas heat exchanger HX-NG; the second heat exchange medium in the second heat exchange cycle can circulate in the following direction: cold end of charging heat exchanger HX-C, cold end of cold storage tank CD, hot end of cold storage tank CD, and hot end of charging heat exchanger HX-C.

[0071] 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.

[0072] like Figure 4 As shown, Figure 4 This is Example 1 of the third coupling condition of the coupling system in this embodiment of the invention, applicable to... Figure 1 Example 1 of the structure of a coupled system is shown;

[0073] The third coupling mode is when the LNG-RG system is running 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, so as to realize the regasification of LNG, the regasification of liquefied main gas and the cold storage of the LAES system.

[0074] Specifically, in the first heat exchange cycle, the cold energy generated by the regasification of LNG during the operation of the LNG-RG system can be transferred to the second heat exchange medium in the charging heat exchanger HX-C, which is in the second heat exchange cycle, through the first heat exchange medium. Then, the cold energy is transferred to the cold storage tank CD for storage through the second heat exchange medium in the second heat exchange cycle. Conversely, after transferring the cold energy to the cold storage tank CD, the second heat exchange medium, which loses its cold energy and heats up, transfers its heat energy to the first heat exchange medium in the first heat exchange cycle in the charging heat exchanger HX-C, thereby enabling the LNG in the LNG-RG system to absorb heat energy and achieve regasification. At the same time, in the second heat exchange cycle, the cold energy generated by the regasification of the liquefied main gas under the discharge condition of the LAES system is also transferred to the cold storage tank CD through the second heat exchange medium. Conversely, after transferring the cold energy to the cold storage tank CD, the second heat exchange medium, which loses its cold energy and heats up, transfers its heat energy to the liquefied main gas in the discharge heat exchanger HX-C, thereby enabling the liquefied main gas under the discharge condition of the LAES system to absorb heat energy and achieve regasification.

[0075] Furthermore, at this time, the first heat exchange medium in the first heat exchange cycle circulates in the following direction: cold end of natural gas heat exchanger HX-NG, cold end of charging heat exchanger HX-C, hot end of charging heat exchanger HX-C, and hot end of natural gas heat exchanger HX-NG; the second heat exchange medium in the second heat exchange cycle can circulate in the following direction: cold end of charging heat exchanger HX-C, cold end of cold storage tank CD, hot end of cold storage tank CD, and hot end of charging heat exchanger HX-C, as well as in the following direction: cold end of discharge heat exchanger HX-DC, cold end of cold storage tank CD, hot end of cold storage tank CD, and hot end of discharge heat exchanger HX-DC.

[0076] When the LNG-RG system is operating and the LAES system is in charging, quiescent, discharging, or changing conditions, the first heat exchange medium in the first heat exchange cycle maintains a circulation direction of flowing from the cold end of the natural gas heat exchanger HX-NG to the cold end of the charging heat exchanger HX-C, the hot end of the charging heat exchanger HX-C, and the hot end of the natural gas heat exchanger HX-NG; the second heat exchange medium in the second heat exchange cycle exchanges cold energy with the first heat exchange medium in the charging heat exchanger HX-C.

[0077] In the coupling system of this invention, since both the first and second heat exchange cycles involve charging heat exchangers, the natural gas heat exchanger, charging heat exchanger, heat storage tank, and discharge heat exchanger can all transfer cold and heat energy between them through the first heat exchange medium and / or the second heat exchange medium. This enables the effective coupling and utilization of cold and heat energy under the respective operating conditions of the LNG-RG system and the LAES system, improving the coupling system and enhancing the effective coupling and utilization rate of cold and heat energy between the systems. Simultaneously, it ensures the continuous operation of the LNG-RG system under various operating conditions coupled with the LAES system, allowing either the LAES system or the LNG-RG system to switch operating conditions according to its actual needs.

[0078] Furthermore, when the LNG-RG system is operating and the LAES system is in charging, stabilizing, discharging, or undergoing a change in operating condition, the flow direction of the first heat exchange medium in the first heat exchange cycle remains unchanged. In the second heat exchange cycle, when the LNG-RG system is operating and the LAES system is in charging condition, the second heat exchange medium flows out from the cold end of the cold storage tank, exchanges its own cold energy with the main gas, and then flows back from the hot end of the cold storage tank. When the LNG-RG system is operating and the LAES system is in stabilizing or discharging condition, the second heat exchange medium flows out from the hot end of the cold storage tank, absorbs the cold energy from the LNG-RG system and / or the cold energy from the regasification process of the liquefied main gas, and then flows back from the cold end of the cold storage tank.

[0079] In some embodiments of the present invention, the natural gas regasification path, the main gas liquefaction path, the liquefied main gas regasification path, the first heat exchange cycle, and the second heat exchange cycle can all be independent paths and are not interconnected. Some heat exchangers in the embodiments of the present invention have at least two independent heat exchange pipes. For example, a natural gas heat exchanger supporting cold energy exchange between LNG and the first heat exchange medium should have at least two independent heat exchange pipes, and the two independent heat exchange pipes should be able to effectively exchange cold energy. For a charging heat exchanger supporting cold energy exchange between the first heat exchange medium, the main gas under charging conditions, and the second heat exchange medium, it should have at least three independent heat exchange pipes. Some embodiments of the present invention may have some variations from the above, but the principles remain the same, and will not be elaborated further.

[0080] like Figure 5 As shown, Figure 5 This is Example 1 of the fourth coupling condition of the coupling system in this embodiment of the invention, applicable to... Figure 1 Example 1 of the structure of a coupled system is shown;

[0081] In some embodiments, the LAES system of the present invention further includes: a gas phase passage running through the natural gas heat exchanger HX-NG, used to transport purified ambient air through the gas phase passage when the LNG-RG system is operating and the LAES system is shut down or the cold storage tank has excess cold energy, and to allow it to exchange cold energy with the LNG-RG system within the natural gas heat exchanger. This gas phase passage can be independent of the natural gas regasification path and the heat exchange circulation path within the natural gas heat exchanger, or it can be directly formed using the heat exchange circulation path within the natural gas heat exchanger.

[0082] In some embodiments, the coupling system of liquefied natural gas regasification and liquid air energy storage in the present invention can cut off the cold energy exchange between the LNG-RG system and the LAES system when the LNG-RG system is shut down. That is, by cutting off the cold energy exchange between the two systems, the decoupling between the two systems is achieved, so that the LAES system can operate independently with its own independent system architecture at this time.

[0083] like Figure 6 As shown, Figure 6 This is Example 1 of the fifth coupling condition of the coupling system in this embodiment of the invention, applicable to... Figure 1 Example 1 of the structure of a coupled system is shown;

[0084] When the LNG-RG system is shut down and the LAES system is in charging condition, the second heat exchange medium in the second heat exchange cycle circulates in the following direction: cold end of the cold storage tank CD, cold end of the charging heat exchanger HX-C, hot end of the charging heat exchanger HX-C, and hot end of the cold storage tank CD. The main gas under the charging condition of the LAES system exchanges cold energy with the second heat exchange medium in the charging heat exchanger HX-C. That is, when the LAES system is in charging condition, the second heat exchange medium in the second heat exchange cycle transfers the cold energy of the cold storage tank CD to the main gas under the charging condition of the LAES system, thereby cooling down the main gas and transferring the heat energy of the main gas under the charging condition of the LAES system to the cold storage tank.

[0085] like Figure 7 As shown, Figure 7 This is Example 2 of the fifth coupling condition of the coupling system in this embodiment of the invention, applicable to... Figure 1 Example 1 of the structure of a coupled system is shown;

[0086] When the LNG-RG system is shut down and the LAES system is in discharge mode, the second heat exchange medium in the second heat exchange cycle circulates in the following direction: cold end of discharge heat exchanger HX-DC, cold end of cold storage tank CD, hot end of cold storage tank CD, and hot end of discharge heat exchanger HX-DC. The liquefied main gas under the discharge mode of the LAES system exchanges cold energy with the second heat exchange medium in the discharge heat exchanger HX-DC. That is, when the LAES system is in discharge mode, the second heat exchange medium in the second heat exchange cycle transfers the cold energy of the regasification of the liquefied main gas under the discharge mode of the LAES system to the cold storage tank for storage, and transfers the heat energy of the cold storage tank to the liquefied main gas under the discharge mode of the LAES system, thereby realizing the regasification of the liquefied main gas.

[0087] like Figure 8 As shown, Figure 8 This is a second example of the structure of the coupled system of the LNG-RG system and the LAES system in this invention embodiment;

[0088] In this embodiment, 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, 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.

[0089] Specifically,

[0090] The cold storage tanks (CDs) include: shallow cold storage tanks (SCDs) for storing and releasing shallow cold energy, and deep cold storage tanks (DCDs) for storing and releasing deep cold energy;

[0091] The natural gas heat exchanger HX-NG includes: a cryogenic natural gas heat exchanger HX-NG1 and a shallow-cold natural gas heat exchanger HX-NG2 arranged sequentially along the liquefied natural gas regasification path and in the direction of liquefied natural gas regasification.

[0092] The charging heat exchanger HX-C includes: a shallow-cold charging heat exchanger HX-SC and a deep-cold charging heat exchanger HX-CB arranged sequentially along the main gas liquefaction direction on the main gas liquefaction path.

[0093] The discharge heat exchanger HX-DC includes: a cryogenic discharge heat exchanger HX-DC1 and a shallow discharge heat exchanger HX-DC2 arranged sequentially along the regasification direction of the liquefied main gas in the regasification path of the liquefied main gas.

[0094] The first heat exchange medium includes: a first shallow cold heat exchange medium and a first deep cold heat exchange medium; the second heat exchange medium includes: a second shallow cold heat exchange medium and a second deep cold heat exchange medium.

[0095] The first heat exchange cycle includes: a first shallow cold closed loop for cold energy exchange between a shallow cold natural gas heat exchanger HX-NG2 and a shallow cold charging heat exchanger HX-SC using a first shallow cold heat exchange medium; and a first deep cold closed loop for cold energy exchange between a deep cold natural gas heat exchanger HX-NG1 and a deep cold charging heat exchanger HX-CB using a first deep cold heat exchange medium; wherein, in the first shallow cold closed loop, the hot ends of the shallow cold natural gas heat exchanger HX-NG2 and the shallow cold charging heat exchanger HX-SC are respectively connected, and the cold ends are respectively connected; in the first deep cold closed loop, the hot ends of the deep cold natural gas heat exchanger HX-NG1 and the deep cold charging heat exchanger HX-CB are respectively connected, and the cold ends are respectively connected.

[0096] The second heat exchange cycle includes: a second shallow cold closed loop for cold energy exchange between the shallow cold charging heat exchanger HX-SC, the shallow cold tank SCD, and the shallow cold discharging heat exchanger HX-DC2 using a second shallow cold heat exchange medium; and a second deep cold closed loop for cold energy exchange between the deep cold charging heat exchanger HX-CB, the deep cold tank DCD, and the deep cold discharging heat exchanger HX-DC1 using a second deep cold heat exchange medium; wherein, in the second shallow cold closed loop, the hot ends of the shallow cold charging heat exchanger HX-SC, the shallow cold tank SCD, and the shallow cold discharging heat exchanger HX-DC2 are connected separately, and the cold ends of the deep cold closed loop are connected separately between the deep cold charging heat exchanger HX-CB, the deep cold tank DCD, and the deep cold discharging heat exchanger HX-DC1.

[0097] 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.

[0098] like Figure 9 As shown, Figure 9 This is a third example of the structure of the coupled system of the LNG-RG system and the LAES system in this invention embodiment;

[0099] In some embodiments of the present invention, the shallow cold charging heat exchanger HX-SC includes: a first shallow cold charging heat exchanger HX-SC1 and a second shallow cold charging heat exchanger HX-SC2 arranged sequentially along the main gas liquefaction path and the main gas liquefaction direction; wherein, 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 a first shallow cold heat exchange medium; 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 a second shallow cold heat exchange medium.

[0100] 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 separately, and the cold ends are connected separately; 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 separately, and the cold ends are connected separately.

[0101] The following example demonstrates the operating conditions of the coupled system after dividing the cold energy into shallow cold energy and deep cold energy:

[0102] When the LNG-RG system is operating and the LAES system is in charging, quiescent, discharging, or changing condition, the first cryogenic heat exchange medium in the first cryogenic closed loop maintains a circulation direction of cold end of cryogenic natural gas heat exchanger HX-NG1, cold end of cryogenic charging heat exchanger HX-CB, hot end of cryogenic charging heat exchanger HX-CB, and hot end of cryogenic natural gas heat exchanger HX-NG1; at the same time, the first shallow cryogenic heat exchange medium in the first shallow cryogenic closed loop maintains a circulation direction of cold end of shallow cryogenic natural gas heat exchanger HX-NG2, cold end of first shallow cryogenic charging heat exchanger HX-SC1, hot end of first shallow cryogenic charging heat exchanger HX-SC1, and hot end of shallow cryogenic natural gas heat exchanger HX-NG2.

[0103] like Figure 10 As shown, Figure 10 This is Example 2 of the first coupling condition of the coupling system in this embodiment of the invention, applicable to... Figure 9 Example three of the structure of the coupled system shown;

[0104] When the LNG-RG system is operating and the LAES system is in charging mode, the second shallow-cooled heat exchange medium in the second shallow-cooled closed loop circulates in the following direction: hot end of the first shallow-cooled charging heat exchanger HX-SC1, hot end of the shallow-cooled tank SCD, cold end of the shallow-cooled tank SCD, and cold end of the first shallow-cooled charging heat exchanger HX-SC1; and in the following direction: cold end of the shallow-cooled tank SCD, cold end of the second shallow-cooled charging heat exchanger HX-SC2, hot end of the second shallow-cooled charging heat exchanger HX-SC2, and hot end of the shallow-cooled tank SCD. The flow direction is circulated; at the same time, the second cryogenic heat exchange medium in the second cryogenic closed loop circulates in the direction of 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; wherein, the main gas under the charging condition of the LAES system exchanges cold energy with the corresponding heat exchange medium in the first shallow cryogenic charging heat exchanger HX-SC1, the second shallow cryogenic charging heat exchanger HX-SC2, and the cryogenic charging heat exchanger HX-CB in sequence.

[0105] like Figure 11 As shown, Figure 11 This is a second example of the second coupling condition of the coupling system in this embodiment of the invention, applicable to... Figure 9 Example three of the structure of the coupled system shown;

[0106] When the LNG-RG system is operating and the LAES system is in a static state, the second shallow-cold heat exchange medium in the second shallow-cold closed loop circulates in the following 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, replenishing the shallow-cold tank SCD with shallow-cold energy. At the same time, the second deep-cold heat exchange medium in the second deep-cold closed loop circulates in the following direction: cold end of the deep-cold charging heat exchanger HX-CB, cold end of the deep-cold tank DCD, hot end of the deep-cold tank DCD, and hot end of the deep-cold charging heat exchanger HX-CB, replenishing the deep-cold tank DCD with deep-cold energy.

[0107] like Figure 12 As shown, Figure 12 This is Example 2 of the third coupling condition of the coupling system in this embodiment of the invention, applicable to... Figure 9 Example three of the structure of the coupled system shown;

[0108] When the LNG-RG system is operating and the LAES system is in discharge mode, 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; simultaneously, the second deep-cold heat exchange medium in the second deep-cold closed loop... The heat medium circulates in the following flow direction: cold end of cryogenic charging heat exchanger HX-CB, cold end of cryogenic tank DCD, hot end of cryogenic tank DCD, and hot end of cryogenic charging heat exchanger HX-CB; and in the following flow direction: cold end of cryogenic discharge heat exchanger HX-DC1, cold end of cryogenic tank DCD, hot end of cryogenic tank DCD, and hot end of cryogenic discharge heat exchanger HX-DC1, to replenish cryogenic energy to cryogenic tank DCD; wherein, the liquefied main gas under the discharge condition of the LAES system 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 in sequence.

[0109] In some embodiments, the coupling system in this invention further includes: an air purifier (not shown), a compressor C, a cryogenic expander CE, a liquid-gas separator LAS, and a liquid air storage tank LAD arranged sequentially along the main gas liquefaction path and in the main gas liquefaction direction; wherein, a first shallow cold charging heat exchanger HX-SC1 is located before the main gas inlet of the compressor C, a second shallow cold charging heat exchanger HX-SC2 is located between the compressor C and the cryogenic expander CE; and a deep cold charging heat exchanger HX-CB is located between the second shallow cold charging heat exchanger HX-SC2 and the cryogenic expander CE.

[0110] When the LNG-RG system is operating and the LAES system is in charging 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, 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 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.

[0111] 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 used to first cool the main gas before compression in the LAES system. This allows for cryogenic compression of the main gas during subsequent compression processes, reducing the overall power consumption of the compressor unit and lowering 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.

[0112] like Figure 13 As shown, Figure 13 This is Example 3 of the first coupling condition of the coupling system in this embodiment of the invention, applicable to... Figure 9 The example of the coupled system shown in Example 3 uses multi-stage compression.

[0113] Preferably, when using a compressor unit to perform multi-stage compression of the main gas, shallow cold energy is used to exchange cold energy after each stage of the compressor. For example, when using a three-stage compressor unit, including a first-stage compressor C1, a second-stage compressor C2, and a third-stage compressor C3 connected in sequence, a second shallow cold charging heat exchanger HX-SC2, a third shallow cold charging heat exchanger HX-SC3, and a fourth shallow cold charging heat exchanger HX-SC4 are provided after each stage of the compressor. Among them, the second shallow cold charging heat exchanger HX-SC2 corresponds to the first-stage compressor C1 and is used to cool the main gas output by the first-stage compressor C1; the third shallow cold charging heat exchanger HX-SC3 corresponds to the second-stage compressor C2 and is used to cool the main gas output by the second-stage compressor C2; and the fourth shallow cold charging heat exchanger HX-SC4 corresponds to the first-stage compressor C3 and is used to cool the main gas output by the first-stage compressor C3. In this case, the fourth shallow cold charging heat exchanger is close to the deep cold charging heat exchanger.

[0114] like Figure 14 As shown, Figure 14 This is example four of the structural examples of the coupled system of the LNG-RG system and the LAES system in this invention. Figure 9 Based on the structure shown in Example 3, an ultra-cold charging heat exchanger HX-UC is added; Figure 15This is Example 4 of the first coupling condition of the coupled system in this embodiment of the invention, applicable to... Figure 14 Example four of the structure of the coupled system is shown;

[0115] In some embodiments, the LAES system of this invention further includes: an ultracold charging heat exchanger HX-UC connected to both the main gas liquefaction path and the return main gas path; wherein, the ultracold charging heat exchanger HX-UC is located after the cryogenic charging heat exchanger HX-CB along the main gas liquefaction direction on the main gas liquefaction path, and before the cryogenic charging heat exchanger HX-CB along the return main gas direction on the return main gas path, for the cascade recovery and use of ultracold and cryogenic energy from the return main gas. Furthermore, the return main gas path can also pass through the cryogenic charging heat exchanger HX-CB and be redirected back to the main gas liquefaction path.

[0116] like Figure 16 As shown, Figure 16 This is Example 2 of the fourth coupling condition of the coupling system in this embodiment of the invention, applicable to... Figure 9 Example three of the structure of the coupled system shown;

[0117] In some embodiments of the present invention, the LAES system further includes a gas phase passage running through the shallow cold natural gas heat exchanger HX-NG2 and the deep cold natural gas heat exchanger HX-NG1, for conveying purified ambient air through the gas phase passage when the LNG-RG system is running and the LAES system is shut down or the cold storage tank has excess cold energy, and allowing it to exchange cold energy with the LNG-RG system sequentially in the shallow cold natural gas heat exchanger and the deep cold natural gas heat exchanger.

[0118] 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.

[0119] In some embodiments, the LAES system's own cryogenic storage equipment 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 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's operating parameters and the actual low-temperature operation performance and parameters of the compressor.

[0120] like Figure 17As shown, Figure 17 This is the fifth example of the structure of the coupled system of the LNG-RG system and the LAES system in the embodiments of the present invention.

[0121] 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.

[0122] In some embodiments, each independent shallow-cooled tank (SCD) and deep-cooled tank (DCD) can be arranged in pairs. For example, a first shallow-cooled tank (SCD1) and a second shallow-cooled tank (SCD2) can replace the shallow-cooled tank (SCD), and a first deep-cooled tank (DCD1) and a second deep-cooled tank (DCD2) can replace the deep-cooled tank (DCD). Both shallow-cooled tanks (SCD1 and SCD2) contain only one portion of the second shallow-cooled heat exchange medium. Before charging, shallow-cooled tank (SCD1) contains a relatively cold second shallow-cooled heat exchange medium, while shallow-cooled tank (SCD2) is empty. During charging, the second shallow-cooled heat exchange medium in shallow-cooled tank (SCD1) continuously flows into shallow-cooled tank (SCD2), releasing cold energy to cool the main gas. After charging, shallow-cooled tank (SCD1) is empty, and shallow-cooled tank (SCD2) is full. During resting and discharging, the warmer second shallow-cooled heat exchange medium in shallow-cooled tank (SCD2) continuously flows into SCD1, absorbing the cold energy output from the LNG-RG system and the cold energy generated by LAES discharge.

[0123] In this embodiment of the invention, the LNG-RG system utilizes natural gas in the liquefied natural gas regasification path as a cold energy carrier to directly exchange cold energy in the LAES system; or, it utilizes other heat exchange media as a cold energy carrier to indirectly exchange cold energy with the LAES system. Specifically, using natural gas in the 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, through which the cold energy of the natural gas is transferred to the main gas for liquefaction, and the heat energy of the main gas is transferred to the natural gas for regasification.

[0124] 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, which can avoid placing high-pressure natural gas and high-pressure air in the same equipment.

[0125] 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 system for LNG-RG and LAES, characterized in that, Including LNG-RG systems and LAES systems; The LNG-RG system includes a natural gas heat exchanger connected to the liquefied natural gas regasification path; the LAES system includes a cold storage tank, a charging heat exchanger connected to the main gas liquefaction path, and a discharging heat exchanger connected to the liquefied main gas regasification path; the natural gas heat exchanger and the charging heat exchanger form a first heat exchange cycle for cold energy exchange using a first heat exchange medium; the charging heat exchanger, the cold storage tank, and the discharging heat exchanger form a second heat exchange cycle for cold energy exchange using a second heat exchange medium; wherein, in the first heat exchange cycle, the hot ends of the natural gas heat exchanger and the charging heat exchanger are connected separately, and the cold ends are connected separately; in the second heat exchange cycle, the hot ends of the charging heat exchanger, the cold storage tank, and the discharging heat exchanger are connected separately, and the cold ends are connected separately. The cold storage tank includes: a shallow cold storage tank for storing and releasing shallow cold energy, and a deep cold storage tank for storing and releasing deep cold energy; the natural gas heat exchanger includes: a deep cold natural gas heat exchanger and a shallow cold natural gas heat exchanger arranged sequentially along the liquefied natural gas regasification direction on the liquefied natural gas regasification path; the charging heat exchanger includes: a shallow cold charging heat exchanger and a deep cold charging heat exchanger arranged sequentially along the main gas liquefaction direction on the main gas liquefaction path; the discharge heat exchanger includes: a deep cold discharge heat exchanger and a shallow cold discharge heat exchanger arranged sequentially along the liquefied main gas regasification direction on the liquefied main gas regasification path; the first heat exchange medium includes: a first shallow cold heat exchange medium and a first deep cold heat exchange medium; the second heat exchange medium includes: a second shallow cold heat exchange medium and a second deep cold heat exchange medium. The first heat exchange cycle includes: a first shallow-cold closed loop for energy exchange between the shallow-cold natural gas heat exchanger and the shallow-cold charging heat exchanger using a first shallow-cold heat exchange medium; and a first deep-cold closed loop for energy exchange between the deep-cold natural gas heat exchanger and the deep-cold charging heat exchanger using a first deep-cold heat exchange medium; wherein, in the first shallow-cold closed loop, the hot ends of the shallow-cold natural gas heat exchanger and the shallow-cold charging heat exchanger are respectively connected, and the cold ends of the deep-cold natural gas heat exchanger and the deep-cold charging heat exchanger are respectively connected; the second heat exchange cycle includes: a second shallow-cold closed loop for energy exchange between the shallow-cold charging heat exchanger, the shallow-cold tank, and the shallow-cold discharge heat exchanger using a second shallow-cold heat exchange medium; and a second deep-cold closed loop for energy exchange between the deep-cold charging heat exchanger, the deep-cold tank, and the deep-cold discharge heat exchanger using a second deep-cold heat exchange medium; In the second shallow-cold closed loop, the hot ends of the shallow-cold charging heat exchanger, the shallow-cold tank, and the shallow-cold discharging heat exchanger are connected to each other, and the cold ends are connected to each other respectively; in the second deep-cold closed loop, the hot ends of the deep-cold charging heat exchanger, the deep-cold tank, and the deep-cold discharging heat exchanger are connected to each other, and the cold ends are connected to each other respectively.

2. The coupling system according to claim 1, characterized in that, When the LNG-RG system is operating and the LAES system is in charging, stabilizing, discharging, or undergoing a change in operating condition, the first heat exchange medium in the first heat exchange cycle maintains a circulation direction of the cold end of the natural gas heat exchanger, the cold end of the charging heat exchanger, the hot end of the charging heat exchanger, and the hot end of the natural gas heat exchanger; the second heat exchange medium in the second heat exchange cycle exchanges cold energy with the first heat exchange medium in the charging heat exchanger.

3. The coupling system according to claim 1, characterized in that, When the LNG-RG system is shut down and the LAES system is in charging mode, the second heat exchange medium in the second heat exchange cycle circulates in the following direction: cold end of the cold storage tank, cold end of the charging heat exchanger, hot end of the charging heat exchanger, and hot end of the cold storage tank. The main gas in the LAES system charging mode exchanges cold energy with the second heat exchange medium within the charging heat exchanger. When the LNG-RG system is shut down and the LAES system is in discharging mode, the second heat exchange medium in the second heat exchange cycle circulates in the following direction: cold end of the discharging heat exchanger, cold end of the cold storage tank, hot end of the cold storage tank, and hot end of the discharging heat exchanger. The liquefied main gas in the LAES system discharging mode exchanges cold energy with the second heat exchange medium within the discharging heat exchanger.

4. The coupling system according to claim 1, characterized in that, The shallow-cold charging heat exchanger includes: a first shallow-cold charging heat exchanger and a second shallow-cold charging heat exchanger arranged sequentially along the main gas liquefaction direction on the main gas liquefaction path; wherein, the shallow-cold natural gas heat exchanger and the first shallow-cold charging heat exchanger form a first shallow-cold closed loop for cold energy exchange using a first shallow-cold heat exchange medium; the first shallow-cold charging heat exchanger, the second shallow-cold charging heat exchanger, the shallow-cold tank, and the shallow-cold discharge heat exchanger form a second shallow-cold closed loop for cold energy exchange using a second shallow-cold heat exchange medium; wherein, in the first shallow-cold closed loop, the hot ends of the shallow-cold natural gas heat exchanger and the first shallow-cold charging heat exchanger are respectively connected, and the cold ends are respectively connected; in the second shallow-cold closed loop, the hot ends of the first shallow-cold charging heat exchanger, the second shallow-cold charging heat exchanger, the shallow-cold tank, and the shallow-cold discharge heat exchanger are respectively connected, and the cold ends are respectively connected.

5. The coupling system according to claim 4, characterized in that, When the LNG-RG system is operating and the LAES system is in charging, quiescent, discharging, or undergoing a change in operating condition, the first cryogenic heat exchange medium in the first cryogenic closed loop maintains a circulation direction of the cold end of the cryogenic natural gas heat exchanger, the cold end of the cryogenic charging heat exchanger, the hot end of the cryogenic charging heat exchanger, and the hot end of the cryogenic natural gas heat exchanger; simultaneously, the first shallow cryogenic heat exchange medium in the first shallow cryogenic closed loop maintains a circulation direction of the cold end of the shallow cryogenic natural gas heat exchanger, the cold end of the first shallow cryogenic charging heat exchanger, the hot end of the first shallow cryogenic charging heat exchanger, and the hot end of the shallow cryogenic natural gas heat exchanger.

6. The coupling system according to claim 4, characterized in that, When the LNG-RG system is operating and the LAES system is in charging mode, 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, hot end of the shallow-cold tank, cold end of the shallow-cold tank, and cold end of the first shallow-cold charging heat exchanger; and in the following flow direction: cold end of the shallow-cold tank, cold end of the second shallow-cold charging heat exchanger, hot end of the second shallow-cold charging heat exchanger, and hot end of the cold storage tank; simultaneously, the second deep-cold heat exchange medium in the second deep-cold closed loop circulates in the following flow direction: hot end of the deep-cold charging heat exchanger, hot end of the deep-cold tank, cold end of the deep-cold tank, and cold end of the deep-cold charging heat exchanger; the main gas under the LAES system charging mode sequentially exchanges cold energy with the corresponding heat exchange medium in the first shallow-cold charging heat exchanger, the second shallow-cold charging heat exchanger, and the deep-cold charging heat exchanger.

7. The coupling system according to claim 4, characterized in that, When the LNG-RG system is operating and the LAES system is in a static state, 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, the cold end of the shallow-cold tank, the hot end of the shallow-cold tank, and the hot end of the first shallow-cold charging heat exchanger, replenishing the shallow-cold tank with shallow-cold energy; at the same time, the second deep-cold heat exchange medium in the second deep-cold closed loop circulates in the direction of the cold end of the deep-cold charging 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 charging heat exchanger, replenishing the deep-cold tank with deep-cold energy.

8. The coupling system according to claim 4, characterized in that, When the LNG-RG system is operating and the LAES system is in discharge mode, 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, cold end of the shallow-cold tank, hot end of the shallow-cold tank, and hot end of the first shallow-cold charging heat exchanger; and, in the following flow direction: cold end of the shallow-cold discharge heat exchanger, cold end of the shallow-cold tank, hot end of the shallow-cold tank, and hot end of the shallow-cold discharge heat exchanger, to replenish shallow-cold energy to the shallow-cold tank; simultaneously, the second deep-cold heat exchange medium in the second deep-cold closed loop circulates in the following flow direction: cold end of the deep-cold charging heat exchanger, cold end of the deep-cold tank, hot end of the deep-cold tank, and hot end of the deep-cold charging heat exchanger; and, in the following flow direction: cold end of the deep-cold discharge heat exchanger, cold end of the deep-cold tank, hot end of the deep-cold tank, and hot end of the deep-cold discharge heat exchanger, to replenish deep-cold energy to the deep-cold tank; 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 and the shallow cryogenic discharge heat exchanger in sequence.

9. The coupling system according to claim 4, characterized in that, The LAES system further includes: a compressor, a cryogenic expander, a liquid-gas separator, and a liquid air storage tank arranged sequentially along the main gas liquefaction path; wherein, the first shallow cryogenic charging heat exchanger is located before the main gas inlet of the compressor, the second shallow cryogenic charging heat exchanger is located between the compressor and the cryogenic expander; and the deep cryogenic charging heat exchanger is located between the second shallow cryogenic charging heat exchanger and the cryogenic expander.

10. The coupling system according to claim 1, characterized in that, The LAES system further includes: an ultracold charging heat exchanger simultaneously connected to the main gas liquefaction path and the return main gas path; wherein, the ultracold charging heat exchanger is located after the cryogenic charging heat exchanger along the main gas liquefaction direction on the main gas liquefaction path, and is located before the cryogenic charging heat exchanger along the return main gas direction on the return main gas path, for the cascade recovery and use of ultracold and cryogenic energy from the return main gas.

11. The coupling system according to claim 1, characterized in that, Also includes: A gas phase passage running through the shallow-cold natural gas heat exchanger and the deep-cold natural gas heat exchanger 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 the cold storage tank has excess cold energy, so that it can 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.

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