Natural gas energy storage system

Abstract

The invention provides a natural gas energy storage system. The natural gas energy storage system comprises a first heat exchanger, an expansion generator, a J-T valve, a first liquid separation tank and an LNG storage tank. During working, natural gas in a natural gas pipe network firstly enters the first fluid channel of the first heat exchanger, one part of the natural gas returns to the second fluid channel of the first heat exchanger after being expanded, generated and cooled by the expansion generator, and the other part of the natural gas returns to the first fluid channel again; the natural gas in the second fluid channel is the natural gas in the first fluid channel and is output to a natural gas output pipeline after being cooled, the cooled natural gas is further throttled and cooled through a J-T valve and then enters the first liquid separation tank, a gas phase enters the second fluid channel, and a liquid phase enters the LNG storage tank for storage. According to the natural gas energy storage system, pressure energy of natural gas is utilized for power generation, the pressure energy is converted into cold energy, cold energy is provided for natural gas liquefaction, and the liquefied natural gas is stored.

Description

Technical Field

[0001] The present invention relates to the technical field of energy conversion, and in particular to a natural gas energy storage system. Background Art

[0002] Global offshore oil and gas production is increasing day by day, among which ultra-deepwater natural gas production has increased rapidly year-on-year. At the same time, my country's offshore oil and gas exploration and development efforts are also increasing, and new discoveries and new oil and gas structure evaluations are constantly being completed. With the development of offshore exploration technology towards precision, key core technology equipment has made major breakthroughs, offshore oil and gas development engineering technology has continued to advance in deep water, and the effect of digital empowerment of offshore oil and gas production has emerged, and offshore oil and gas production has steadily increased year by year. However, the increase in production has brought about the problem of imbalance between natural gas supply and demand throughout the year, resulting in a large amount of natural gas storage energy wasted during the off-season for natural gas demand. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a natural gas energy storage system, which aims to solve the problem in the related art that a large amount of natural gas storage energy is wasted in the off-season of natural gas demand due to the continuous increase in natural gas production.

[0004] The present invention provides a natural gas energy storage system, comprising a first heat exchanger, an expansion generator, a JT valve, a first liquid separation tank and an LNG storage tank, wherein: The first heat exchanger includes a first fluid channel, a second fluid channel, a first interface, a second interface, a third interface, a fourth interface, a fifth interface and a sixth interface. The first interface, the second interface, the third interface and the fourth interface are all connected to the first fluid channel, the fifth interface and the sixth interface are both connected to the second fluid channel, the first interface is used to connect to the natural gas pipeline network, the second interface is respectively connected to the inlet of the expansion generator and the third interface, the fourth interface is connected to the inlet of the first liquid separation tank through the JT valve, the fifth interface is used to connect to the outlet of the expansion generator, the sixth interface is used to connect to the natural gas transmission pipeline, the liquid phase outlet of the first liquid separation tank is connected to the LNG storage tank, the gas phase outlet of the first liquid separation tank is connected to the fifth interface, and the power output end of the expansion generator is used to connect to an electrical device or an electrical storage device.

[0005] The natural gas energy storage system provided by the present invention further includes a second heat exchanger, a hydrogen expander, a second liquid separation tank and a liquid hydrogen storage tank, wherein: The second heat exchanger includes a third fluid channel, a fourth fluid channel, a seventh interface, an eighth interface, a ninth interface, a tenth interface, an eleventh interface and a twelfth interface, the seventh interface and the eighth interface are both connected to the third fluid channel, the ninth interface, the tenth interface, the eleventh interface and the twelfth interface are all connected to the fourth fluid channel, the seventh interface is used to connect to a hydrogen supply system, the eighth interface is connected to the inlet of the hydrogen expander, the outlet of the hydrogen expander is connected to the inlet of the second liquid separator, the liquid phase outlet of the second liquid separator is connected to the liquid hydrogen storage tank, the liquid phase outlets of the second liquid separator and the liquid hydrogen storage tank are both connected to the ninth interface, the tenth interface is connected to the seventh interface, the eleventh interface is connected to the LNG storage tank, and the twelfth interface is used to connect to an LNG export pipeline.

[0006] The natural gas energy storage system provided according to the present invention further includes a natural gas pre-processing device, the inlet of the natural gas pre-processing device is used to connect to the natural gas pipeline network, and the outlet of the natural gas pre-processing device is used to connect to the first interface of the first heat exchanger.

[0007] According to the natural gas energy storage system provided by the present invention, the natural gas pre-processing device includes a dehydration unit, a decarbonization unit, a desulfurization unit and a light hydrocarbon separation unit.

[0008] According to the natural gas energy storage system provided by the present invention, the first heat exchanger and the second heat exchanger are plate-fin heat exchangers or coil-wound heat exchangers.

[0009] According to the natural gas energy storage system provided by the present invention, the power-consuming equipment connected to the power output end of the expansion generator is the natural gas pre-processing device and / or the LNG receiving station.

[0010] According to the natural gas energy storage system provided by the present invention, the power storage device connected to the power output end of the expansion generator is a battery.

[0011] The present invention adopts the above technical solution, which has the following advantages: The natural gas energy storage system provided by the present invention comprises a first heat exchanger, an expansion generator, a JT valve, a first liquid separator and an LNG storage tank. The first heat exchanger comprises a first fluid channel, a second fluid channel, a first interface, a second interface, a third interface, a fourth interface, a fifth interface and a sixth interface, the first interface, the second interface, the third interface and the fourth interface are all in communication with the first fluid channel, the fifth interface and the sixth interface are both connected with the second fluid channel, the first interface is used to be connected with a natural gas pipeline network, the second interface is respectively connected with the inlet of the expansion generator and the third interface, the fourth interface is connected with the inlet of the first liquid separator through the JT valve, the fifth interface is used to be connected with the outlet of the expansion generator, the sixth interface is used to be connected with a natural gas transmission pipeline, the liquid phase outlet of the first liquid separator is connected with the LNG storage tank, the gas phase outlet of the first liquid separator is connected with the fifth interface, and the power output end of the expansion generator is used to be connected with an electric device or an electric storage device. During operation, the natural gas in the natural gas pipeline network enters the first fluid channel of the first heat exchanger through the first interface, and then is discharged through the second interface. Among the discharged natural gas, a natural gas with a larger flow rate enters the expansion generator, and the pressure energy of the natural gas is used to generate pressure difference electricity. The generated electricity is supplied to the power-consuming equipment through the power output end or enters the power storage device for storage. Among the natural gas discharged through the second interface, a natural gas with a smaller flow rate returns to the first fluid channel through the third interface. The temperature of the natural gas after passing through the expansion generator is reduced, and it enters the second fluid channel of the first heat exchanger through the fifth interface of the first heat exchanger. The natural gas with a lower temperature in the second fluid channel provides cold energy for the natural gas in the first fluid channel. The natural gas after cooling and liquefaction is discharged through the fourth interface, and then further throttled and cooled through the JT valve, and then enters the first liquid separation tank. The liquid phase in the first liquid separation tank enters the LNG storage tank for storage, and the gas phase in the first liquid separation tank enters the second fluid channel through the fifth interface of the first heat exchanger, and together with the natural gas with a larger flow rate after passing through the expansion generator, provides cold energy for the natural gas in the first fluid channel. After the natural gas in the second fluid channel provides cold energy for the first fluid channel, it is discharged through the sixth interface and transported to a gas power plant or a downstream pipeline through a natural gas transmission pipeline. The natural gas energy storage system provided by the present invention utilizes the pressure energy of natural gas to generate electricity, converts the pressure energy into cold energy, provides cold energy for natural gas liquefaction, and stores liquefied natural gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] Figure 1 is a flow chart of a natural gas energy storage system provided by one embodiment of the present invention; Figure 2 is a schematic diagram of an interface of a first heat exchanger provided by an embodiment of the present invention; Figure 3 It is a schematic diagram of the interface of the second heat exchanger provided in one embodiment of the present invention.

[0014] Reference numerals: 110: first heat exchanger; 111: first interface; 112: second interface; 113: third interface; 114: fourth interface; 115: fifth interface; 116: sixth interface; 120: expansion generator; 130: JT valve; 140: first liquid separation tank; 150: LNG storage tank; 210: second heat exchanger; 211: seventh interface; 212: eighth interface; 213: ninth interface; 214: tenth interface; 215: eleventh interface; 216: twelfth interface; 220: hydrogen expander; 230: second liquid separation tank; 240: liquid hydrogen storage tank; 300: Natural gas pre-processing device. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0017] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0018] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0020] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0021] The natural gas energy storage system provided by the present invention comprises a first heat exchanger, an expansion generator, a JT valve, a first liquid separator and an LNG storage tank. The first heat exchanger comprises a first fluid channel, a second fluid channel, a first interface, a second interface, a third interface, a fourth interface, a fifth interface and a sixth interface, the first interface, the second interface, the third interface and the fourth interface are all in communication with the first fluid channel, the fifth interface and the sixth interface are both connected with the second fluid channel, the first interface is used to be connected with a natural gas pipeline network, the second interface is respectively connected with the inlet of the expansion generator and the third interface, the fourth interface is connected with the inlet of the first liquid separator through the JT valve, the fifth interface is used to be connected with the outlet of the expansion generator, the sixth interface is used to be connected with a natural gas transmission pipeline, the liquid phase outlet of the first liquid separator is connected with the LNG storage tank, the gas phase outlet of the first liquid separator is connected with the fifth interface, and the power output end of the expansion generator is used to be connected with an electric device or an electric storage device. During operation, the natural gas in the natural gas pipeline network enters the first fluid channel of the first heat exchanger through the first interface, and then is discharged through the second interface. Among the discharged natural gas, a natural gas with a larger flow rate enters the expansion generator, and the pressure energy of the natural gas is used to generate pressure difference electricity. The generated electricity is supplied to the power-consuming equipment through the power output end or enters the power storage device for storage. Among the natural gas discharged through the second interface, a natural gas with a smaller flow rate returns to the first fluid channel through the third interface. The temperature of the natural gas after passing through the expansion generator is reduced, and it enters the second fluid channel of the first heat exchanger through the fifth interface of the first heat exchanger. The natural gas with a lower temperature in the second fluid channel provides cold energy for the natural gas in the first fluid channel. The natural gas after cooling and liquefaction is discharged through the fourth interface, and then further throttled and cooled through the JT valve, and then enters the first liquid separation tank. The liquid phase in the first liquid separation tank enters the LNG storage tank for storage, and the gas phase in the first liquid separation tank enters the second fluid channel through the fifth interface of the first heat exchanger, and together with the natural gas with a larger flow rate after passing through the expansion generator, provides cold energy for the natural gas in the first fluid channel. After the natural gas in the second fluid channel provides cold energy for the first fluid channel, it is discharged through the sixth interface and transported to a gas power plant or a downstream pipeline through a natural gas transmission pipeline. The natural gas energy storage system provided by the present invention utilizes the pressure energy of natural gas to generate electricity, converts the pressure energy into cold energy, provides cold energy for natural gas liquefaction, and stores liquefied natural gas.

[0022] Combine the following Figures 1 to 3 A natural gas energy storage system of the present invention is described.

[0023] An embodiment of the present invention provides a natural gas energy storage system, including a first heat exchanger 110 , an expansion generator 120 , a JT valve 130 , a first liquid separation tank 140 , and an LNG storage tank 150 .

[0024] The first heat exchanger 110 may be a plate-fin heat exchanger or a coiled-tube heat exchanger, etc., and a first fluid channel and a second fluid channel are provided inside the first fluid channel and the fluids in the first fluid channel and the second fluid channel may exchange heat by heat conduction.

[0025] The first heat exchanger 110 is provided with a first interface 111, a second interface 112, a third interface 113, a fourth interface 114, a fifth interface 115 and a sixth interface 116. The first interface 111, the second interface 112, the third interface 113 and the fourth interface 114 are all connected to the first fluid channel, and the fifth interface 115 and the sixth interface 116 are all connected to the second fluid channel.

[0026] The first interface 111 is used to connect to the natural gas output end of the natural gas pipeline network, the second interface 112 is respectively connected to the inlet of the expansion generator 120 and the third interface 113, the fourth interface 114 is used to connect to one end of the JT valve 130, the other end of the JT valve 130 is connected to the inlet of the first liquid separator 140, the liquid phase outlet of the first liquid separator 140 is connected to the LNG storage tank 150, the gas phase outlet of the first liquid separator 140 and the outlet of the expansion generator 120 are both connected to the fifth interface 115, and the sixth interface 116 is used to connect to the natural gas export pipeline.

[0027] During operation, the natural gas output from the natural gas network first enters the first fluid pipeline through the first interface 111 on the first heat exchanger 110, passes through the first fluid channel and is discharged through the second interface 112. A larger flow of the discharged natural gas enters the expansion generator 120, and uses the pressure energy of the natural gas to generate pressure difference power, and a smaller flow returns to the first fluid channel through the third interface 113. The natural gas after passing through the expansion generator 120 is cooled and depressurized, and enters the second fluid channel of the first heat exchanger 110 through the fifth interface 115 in the form of cold fluid, providing cold energy for the natural gas flowing through the first fluid channel. The natural gas after providing cold energy is discharged through the sixth interface 116 and input into the gas power plant or the downstream pipeline network through the natural gas transmission pipeline.

[0028] The natural gas discharged through the second interface 112 and then returned to the first fluid channel through the third interface 113 receives the cold energy in the second fluid channel and then cools down, and then is discharged to the JT valve 130 through the fourth interface 114 for further throttling and cooling, and then enters the first liquid separator 140, and the liquid phase in the first liquid separator 140 enters the LNG storage tank 150 for storage, and the gas phase in the first liquid separator 140 enters the second fluid pipeline through the fifth interface 115, and together with the natural gas discharged from the expansion generator 120, provides cold energy for the natural gas in the first fluid channel.

[0029] The power generated by the expansion generator 120 is output to an electric device or an electric storage device through a power output terminal.

[0030] The natural gas energy storage system provided by the present invention utilizes the pressure energy of natural gas to generate electricity, converts the pressure energy into cold energy, provides cold capacity for natural gas liquefaction, and stores liquefied natural gas.

[0031] In some embodiments, the natural gas energy storage system further includes a second heat exchanger 210 , a hydrogen expander 220 , a second liquid separation tank 230 , and a liquid hydrogen storage tank 240 .

[0032] The second heat exchanger 210 may be a plate-fin heat exchanger or a coiled-tube heat exchanger, etc., and a third fluid channel and a fourth fluid channel are provided inside the second heat exchanger 210. The fluids in the third fluid channel and the fourth fluid channel may exchange heat by heat conduction.

[0033] The second heat exchanger 210 is provided with a seventh interface 211, an eighth interface 212, a ninth interface 213, a tenth interface 214, an eleventh interface 215 and a twelfth interface 216. The seventh interface 211 and the eighth interface 212 are both communicated with the third fluid channel, and the ninth interface 213, the tenth interface 214, the eleventh interface 215 and the twelfth interface 216 are all communicated with the fourth fluid channel.

[0034] The seventh interface 211 is used to connect to the hydrogen supply system, which can be an offshore wind power hydrogen production system. The eighth interface 212 is used to connect to the inlet of the hydrogen expander 220, the outlet of the hydrogen expander 220 is connected to the inlet of the second liquid separator 230, the liquid phase outlet of the second liquid separator 230 is connected to the inlet of the liquid hydrogen storage tank 240, the gas phase outlet of the liquid hydrogen storage tank 240 and the gas phase outlet of the second liquid separator 230 are both connected to the ninth interface 213 of the second heat exchanger 210, the tenth interface 214 is connected to the seventh interface 211, the eleventh interface 215 is used to connect to the outlet of the LNG storage tank 150, and the twelfth interface 216 is used to connect to the LNG external transmission pipeline.

[0035] During operation, the hydrogen supplied by the hydrogen supply system enters the third fluid channel of the second heat exchanger 210 through the seventh interface 211, and then is discharged to the hydrogen expander 220 through the eighth interface 212 of the second heat exchanger 210 for further cooling. The cooled hydrogen is separated into gas and liquid through the second liquid separator 230, and the separated liquid phase enters the liquid hydrogen storage tank 240 for storage. The separated gas phase and the gas phase in the liquid hydrogen storage tank 240 enter the fourth fluid channel of the second heat exchanger 210 through the ninth interface 213 of the second heat exchanger 210. At the same time, the LNG in the LNG storage tank 150 enters the fourth fluid channel of the second heat exchanger 210 through the eleventh interface 215, and then enters the LNG external transmission pipeline through the twelfth interface 216 of the second heat exchanger 210 for external transmission.

[0036] The low-temperature hydrogen entering the fourth fluid channel through the ninth interface 213 of the second heat exchanger 210 and the LNG entering the fifth fluid channel through the eleventh interface 215 of the second heat exchanger 210 are used to cool the hydrogen entering the fourth fluid channel through the seventh interface 211 of the second heat exchanger 210, and the LNG after providing cold is heated and gasified for external transmission.

[0037] The natural gas energy storage system provided by the embodiment of the present invention can utilize the cold energy of LNG to liquefy and store hydrogen.

[0038] In some embodiments, a natural gas pre-processing device 300 is further included, the inlet of the natural gas pre-processing device 300 is used to connect to the natural gas pipeline network, and the outlet of the natural gas pre-processing device 300 is used to connect to the first interface 111 of the first heat exchanger 110.

[0039] The natural gas processing device can be used to dehydrate, decarbonize, desulfurize and separate light hydrocarbons from the natural gas entering the first heat exchanger 110. Specifically, the natural gas processing device is provided with a dehydration unit, a decarbonization unit, a desulfurization unit and a light hydrocarbon separation unit to complete the above impurity separation operation.

[0040] In some embodiments, the power-consuming device connected to the power output terminal of the expansion generator 120 may be a natural gas pre-processing device 300 or an LNG receiving station, or may supply power to both the natural gas pre-processing device 300 and the LNG receiving station.

[0041] In some embodiments, the power storage device connected to the power output terminal of the expansion generator 120 may be a battery.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A natural gas energy storage system, characterized in that: The invention comprises a first heat exchanger (110), an expansion generator (120), a JT valve (130), a first liquid separation tank (140) and an LNG storage tank (150), wherein: The first heat exchanger (110) comprises a first fluid channel, a second fluid channel, a first interface (111), a second interface (112), a third interface (113), a fourth interface (114), a fifth interface (115) and a sixth interface (116); the first interface (111), the second interface (112), the third interface (113) and the fourth interface (114) are all in communication with the first fluid channel, the fifth interface (115) and the sixth interface (116) are both connected to the second fluid channel, the first interface (111) is used to connect to a natural gas pipeline network, the second interface (112) is respectively connected to the expansion joint (116) and the expansion joint (117). The inlet of the expansion generator (120) is connected to the third interface (113), the fourth interface (114) is connected to the inlet of the first liquid separation tank (140) through the JT valve (130), the fifth interface (115) is used to be connected to the outlet of the expansion generator (120), the sixth interface (116) is used to be connected to a natural gas transmission pipeline, the liquid phase outlet of the first liquid separation tank (140) is connected to the LNG storage tank (150), the gas phase outlet of the first liquid separation tank (140) is connected to the fifth interface (115), and the power output end of the expansion generator (120) is used to be connected to an electric device or an electric storage device.

2. The natural gas energy storage system according to claim 1, characterized in that: It also includes a second heat exchanger (210), a hydrogen expander (220), a second liquid separation tank (230) and a liquid hydrogen storage tank (240), wherein: The second heat exchanger (210) comprises a third fluid channel, a fourth fluid channel, a seventh interface (211), an eighth interface (212), a ninth interface (213), a tenth interface (214), an eleventh interface (215) and a twelfth interface (216), the seventh interface (211) and the eighth interface (212) are both in communication with the third fluid channel, the ninth interface (213), the tenth interface (214), the eleventh interface (215) and the twelfth interface (216) are both in communication with the fourth fluid channel, the seventh interface (211) is used to be connected to a hydrogen supply system, and the eighth interface (213) is used to be connected to a hydrogen supply system. The interface (212) is connected to the inlet of the hydrogen expander (220), the outlet of the hydrogen expander (220) is connected to the inlet of the second liquid separator tank (230), the liquid phase outlet of the second liquid separator tank (230) is connected to the liquid hydrogen storage tank (240), the liquid phase outlets of the second liquid separator tank (230) and the liquid hydrogen storage tank (240) are both connected to the ninth interface (213), the tenth interface (214) is connected to the seventh interface (211), the eleventh interface (215) is connected to the LNG storage tank (150), and the twelfth interface (216) is used to be connected to an LNG export pipeline.

3. The natural gas energy storage system according to claim 1 or 2, characterized in that: It also comprises a natural gas pre-processing device (300), the inlet of the natural gas pre-processing device (300) being used to be connected to a natural gas pipeline network, and the outlet of the natural gas pre-processing device (300) being used to be connected to the first interface (111) of the first heat exchanger (110).

4. The natural gas energy storage system according to claim 3, characterized in that: The natural gas pre-processing device (300) comprises a dehydration unit, a decarbonization unit, a desulfurization unit and a light hydrocarbon separation unit.

5. The natural gas energy storage system according to claim 2, characterized in that: The first heat exchanger (110) and the second heat exchanger (210) are plate-fin heat exchangers or coil-wound heat exchangers.

6. The natural gas energy storage system according to claim 3, characterized in that: The electrical equipment connected to the power output end of the expansion generator (120) is the natural gas pre-processing device (300) and / or the LNG receiving station.

7. The natural gas energy storage system according to claim 1, characterized in that: The power storage device connected to the power output end of the expansion generator (120) is a battery.

Images