Liquefied natural gas supply system and liquefied natural gas supply method

Abstract

The invention provides a natural gas supply system and a gas supply method.The liquefied natural gas supply system is provided with a storage device, a compressor, a heat exchanger, a gas supply pipeline, a liquid return pipeline and a gas supply assembly, the compressor communicates with the storage device, natural gas boil-off gas can be compressed, and the natural gas boil-off gas is compressed through the compressor; the heat exchanger is provided with a first heat exchange cavity and a second heat exchange cavity which are spaced, the high-pressure fuel gas formed through compression of the compressor enters the first heat exchange cavity, and natural gas in the storage device is supplied into the second heat exchange cavity through a gas supply pipeline. High-pressure fuel gas in the first heat exchange cavity is liquefied under heat exchange with natural gas in the second heat exchange cavity to form liquefied natural gas, the liquid return pipeline can lead the liquefied natural gas formed in the first heat exchange cavity into the storage device again to be stored, and the gas supply assembly can supply the natural gas in the second heat exchange cavity into gas utilization equipment. And the energy consumption required by liquefaction of the natural gas boil-off gas can be obviously reduced.

Description

Technical Field

[0001] The present application relates to natural gas supply technology, and in particular to a liquefied natural gas supply system and method. Background Art

[0002] With the development of the times, more and more ships use liquefied natural gas (LNG) as the main fuel for their equipment. Gas-using equipment mainly includes main engines, generators, boilers and other equipment.

[0003] The liquefied natural gas (LNG) supply system primarily consists of a storage tank, a gas supply pipeline, and a gas supply regulating assembly. LNG is stored in the tank, and the gas supply pipeline connects the tank to gas-consuming equipment, supplying the natural gas from the tank to the equipment. The gas supply regulating assembly, installed in the gas supply pipeline, adjusts the supply pressure to match the gas demand of the equipment. As the ship sways and the ambient temperature of the storage tank constantly fluctuates, natural gas evaporates from the tank. This evaporated gas exceeds the gas consumption of the equipment. To ensure system stability, the excess gas is discharged, resulting in significant energy waste and environmental pollution.

[0004] To avoid wasting natural gas and polluting the environment, existing liquefied natural gas (LNG) supply systems primarily install cryogenic devices on storage tanks. These devices can liquefy natural gas vapor into liquefied natural gas and return it to the storage tanks for storage. Although cryogenic devices can liquefy natural gas vapor, the energy consumption required during the liquefaction process is high, resulting in higher operating costs for the LNG supply system. Summary of the Invention

[0005] The present application provides a liquefied natural gas (LNG) supply system and a LNG supply method, which are used to solve the technical problem that the liquefaction process of the natural gas boil-off gas in the LNG supply system requires high energy consumption, thereby resulting in high operating costs of the gas supply system.

[0006] In one aspect, the present application provides a liquefied natural gas supply system, comprising:

[0007] a storage device for storing natural gas;

[0008] a compressor, connected to the storage device, for compressing the natural gas boil-off gas generated by the storage device to form high-pressure fuel gas from the natural gas boil-off gas;

[0009] A heat exchanger is provided with a first heat exchange chamber and a second heat exchange chamber spaced apart from each other, wherein the first heat exchange chamber is communicated with the compressor and is used to receive the high-pressure gas generated by the compressor;

[0010] a gas supply pipeline in communication with the storage device and the second heat exchange chamber, for supplying the natural gas from the storage device to the second heat exchange chamber, so as to convert the high-pressure gas in the first heat exchange chamber into liquefied natural gas by heat exchange with the high-pressure gas in the first heat exchange chamber;

[0011] a liquid return pipeline, communicating with the first heat exchange chamber and the storage device, and configured to pass the liquefied natural gas in the first heat exchange chamber into the storage device;

[0012] The gas supply component is communicated with the second heat exchange chamber and is used to supply the natural gas in the second heat exchange chamber to the gas-consuming equipment.

[0013] In some embodiments, the storage device is provided with a first storage chamber and a second storage chamber, the first storage chamber and the second storage chamber are used to store natural gas, the compressor and the liquid return pipeline are both connected to the first storage chamber, and the gas supply pipeline includes a first gas supply pipe, the two ends of the first gas supply pipe are respectively connected to the second heat exchange chamber and the second storage chamber, and are used to supply the natural gas evaporated gas in the second storage chamber into the second heat exchange chamber.

[0014] In some embodiments, the gas supply pipeline also includes a second gas supply pipe, the two ends of which are respectively connected to the second heat exchange chamber and the second storage chamber, and the second gas supply pipe is provided with a gas pump, which is located in the second storage chamber and is used to drive the liquefied natural gas in the second storage chamber to the second heat exchange chamber.

[0015] In some embodiments, the gas supply pipeline further includes a third gas supply pipe, both ends of which are connected to the first heat exchange chamber and the second storage chamber respectively, for supplying natural gas in the first heat exchange chamber into the second heat exchange chamber.

[0016] In some embodiments, the liquid return pipeline includes a first liquid return pipe and a second liquid return pipe, one end of the first liquid return pipe and the second liquid return pipe are connected to the first storage chamber, and the other end of the first liquid return pipe and the second liquid return pipe are connected to the first storage chamber and the second storage chamber respectively.

[0017] In some embodiments, the liquefied natural gas supply system further includes a liquefaction pipeline and a vaporization pipeline, both ends of the liquefaction pipeline and the vaporization pipeline are connected to the second storage chamber, the liquefaction pipeline is provided with a cryogenic cooler for liquefying the natural gas evaporated gas of the storage device through the cryogenic cooler, and the vaporization pipeline is provided with a vaporizer for vaporizing the liquefied natural gas of the storage device through the vaporizer.

[0018] In some embodiments, the gas supply assembly includes a pressurized pipeline and a heating pipeline, the pressurized pipeline and the heating pipeline are arranged in parallel, one end of the pressurized pipeline and the heating pipeline is connected to the second heat exchange cavity, and the other end of the pressurized pipeline and the heating pipeline is used to connect to the gas-consuming equipment;

[0019] The pressurizing pipeline is provided with a compressor, and the compressor is used to pressurize the natural gas supplied to the gas-consuming equipment;

[0020] The heating pipeline is provided with a heater, and the heater is used to heat and gasify the gas supplied to the gas-consuming equipment.

[0021] In another aspect, the present application provides a method for supplying liquefied natural gas, comprising the following steps:

[0022] Supplying the natural gas in the storage device into the second heat exchange chamber of the heat exchanger, and supplying the natural gas boil-off gas into the compressor;

[0023] The compressor compresses the natural gas vapor into high-pressure fuel gas, and supplies the high-pressure fuel gas into the first heat exchange chamber of the heat exchanger;

[0024] The high-pressure gas in the first heat exchange chamber exchanges heat with the natural gas in the second heat exchange chamber to form liquefied natural gas;

[0025] The liquefied natural gas formed in the first heat exchange chamber is returned to the storage device through the liquid return pipeline, and the natural gas in the second heat exchange chamber is supplied to the gas-consuming equipment through the gas supply component.

[0026] In some embodiments, the storage device supplies natural gas into the second heat exchange chamber of the heat exchanger, comprising:

[0027] supplying the boil-off gas of natural gas in the second storage chamber into the second heat exchange chamber through the first gas supply pipe;

[0028] When the amount of natural gas boil-off in the second storage chamber is insufficient, the gas pump passes the liquefied natural gas in the second storage chamber into the second heat exchange chamber through the second gas supply pipe;

[0029] When the amount of liquefied natural gas in the second storage chamber is insufficient, the natural gas in the first storage chamber is supplied to the second heat exchange chamber through the third gas supply pipe.

[0030] In some embodiments, the liquefied natural gas in the first heat exchange chamber is returned to the storage device through a liquid return pipeline, including

[0031] Part of the liquefied natural gas flows into the first storage chamber through the first liquid return pipe, and another part of the liquefied natural gas flows into the second storage chamber through the second liquid return pipe.

[0032] The liquefied natural gas supply system provided by the present application is provided with a storage device, a compressor, a heat exchanger, a gas supply pipeline, a liquid return pipeline and a gas supply component. The storage device can store natural gas, and the liquefied natural gas inside the storage device will continuously form gaseous natural gas evaporation gas during operation. The compressor is connected to the storage device and can compress the natural gas evaporation gas. The natural gas evaporation gas is compressed by the compressor to form high-pressure gas with an increased liquefaction temperature, and the gas temperature is increased. The heat exchanger is provided with a first heat exchange chamber and a second heat exchange chamber spaced apart from each other. The high-pressure gas compressed by the compressor will enter the first heat exchange chamber. The gas supply pipeline is connected to the storage device and the second heat exchange chamber. When the gas supply is working, the natural gas of the storage device is supplied to the second heat exchange chamber through the gas supply pipeline. The natural gas temperature in the second heat exchange chamber is lower than that of the high-pressure gas in the first heat exchange chamber, and will absorb the high-pressure gas in the first heat exchange chamber. Heat. Since the temperature of the natural gas in the second heat exchange chamber is lower than the temperature required for liquefaction of the high-pressure gas in the first heat exchange chamber, the high-pressure gas in the first heat exchange chamber will be liquefied under heat exchange with the natural gas in the second heat exchange chamber to form liquid natural gas. The return liquid pipeline is connected to the first heat exchange chamber and the storage device, and the liquefied natural gas formed in the first heat exchange chamber can be re-entered into the storage device for storage. The gas supply component is connected to the second heat exchange chamber, and the natural gas heated in the second heat exchange chamber can be supplied to the gas-consuming equipment of the ship for use by the gas-consuming equipment. The above gas supply method formed by the gas supply system can, during the period of gas supply to the gas-consuming equipment, make use of the coldness of the natural gas itself and cooperate with the compression of the natural gas boil-off by the compressor to make the natural gas boil-off gas re-liquefy, which can significantly reduce the energy consumption required for liquefaction of the natural gas boil-off gas, thereby reducing the gas supply cost of the liquefied natural gas supply system. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0034] Figure 1 This is a schematic diagram of the structure of the liquefied natural gas supply system provided in an embodiment of the present application;

[0035] Figure 2 This is a flow chart of the liquefied natural gas supply method provided in an embodiment of the present application.

[0036] Reference numerals in the figures:

[0037] 10 - storage device; 11 - first storage chamber; 12 - second storage chamber; 13 - ventilation duct;

[0038] 131 - first manual control valve; 132 - first remote control valve; 14 - infusion tube; 141 - supplementary pump;

[0039] 142—Second remote control valve; 15—Cargo pump;

[0040] 20—compressor;

[0041] 30—heat exchanger;

[0042] 40—air supply pipeline; 41—first air supply pipe; 411—second manual control valve; 42—second air supply pipe; 421—third manual control valve; 43—third air supply pipe; 431—fourth manual control valve;

[0043] 50—return liquid pipeline; 51—first return liquid pipe; 511—fifth manual control valve; 512—third remote control valve; 52—second return liquid pipe; 521—fourth remote control valve;

[0044] 60—gas supply assembly; 61—pressurization pipeline; 611—compressor; 612—first buffer tank; 62—heating pipeline; 621—heater; 63—second buffer tank;

[0045] 70—liquefaction pipeline; 71—cryogenic cooler;

[0046] 80—gasification pipeline; 81—gasifier;

[0047] 90—Cargo loading and unloading station; 100—Refueling station;

[0048] 10a—Gas-using equipment.

[0049] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0050] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0051] Liquefied natural gas (LNG) is widely used in ships to supply gas to equipment such as generators and boilers. The existing LNG supply system mainly installs a cryogenic device on the storage tank. Although the cryogenic device can liquefy the evaporated gas of natural gas, the energy consumption required in the liquefaction process is high, resulting in high operating costs of the natural gas supply system.

[0052] In order to solve the technical problem that the liquefaction process of natural gas boil-off gas requires high energy consumption, resulting in high operating costs of the gas supply system, the present application provides a liquefied natural gas supply system. By utilizing the natural gas's own cooling capacity and cooperating with the compressor to compress the natural gas boil-off gas during the gas supply to the gas-consuming equipment, the natural gas boil-off gas is re-liquefied, which can significantly reduce the energy consumption required for liquefaction of the natural gas boil-off gas, thereby reducing the gas supply cost of the liquefied natural gas supply system.

[0053] It should be noted that the liquefied natural gas supply system described in this application is used for but not limited to ships, etc., and can also be applied to civilian equipment, industrial equipment, natural gas transport vehicles and other equipment. For the sake of convenience, in this application, only the application of the liquefied natural gas supply system to ships is used as an example for explanation. The principles of the application of the liquefied natural gas supply system to civilian equipment, industrial equipment, natural gas transport vehicles and other equipment are essentially the same as those applied to ships, and will not be repeated here.

[0054] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0055] In order to better understand this application, Figure 1 The technical solution of this application is described in detail:

[0056] The present application provides a liquefied natural gas supply system, such as Figure 1 As shown, the system includes a storage device 10, a compressor 20, a heat exchanger 30, a gas supply pipeline 40, a liquid return pipeline 50, and a gas supply assembly 60. The storage device 10 is used to store natural gas. The compressor 20 is in communication with the storage device 10 and is used to compress the natural gas boil-off gas generated by the storage device 10 to form high-pressure natural gas. The heat exchanger 30 is provided with a first heat exchange chamber (not shown) and a second heat exchange chamber (not shown) spaced apart from each other. The first heat exchange chamber is in communication with the compressor 20 and is used to receive the high-pressure natural gas generated by the compressor 20. The gas supply pipeline 40 is in communication with the storage device 10 and the second heat exchange chamber and is used to supply the natural gas from the storage device 10 to the second heat exchange chamber. The natural gas in the first heat exchange chamber is converted into liquefied natural gas through heat exchange with the high-pressure natural gas in the first heat exchange chamber. The liquid return pipeline 50 is in communication with the first heat exchange chamber and the storage device 10 and is used to pass the liquefied natural gas in the first heat exchange chamber into the storage device 10. The gas supply assembly 60 is in communication with the second heat exchange chamber and is used to supply the natural gas in the second heat exchange chamber to the gas-consuming equipment 10a.

[0057] Specifically, the natural gas supply system is provided with a storage device 10, a compressor 20, a heat exchanger 30, a gas supply pipeline 40, a liquid return pipeline 50 and a gas supply component 60. The storage device 10 can store natural gas. The liquefied natural gas inside the storage device 10 will continuously form gaseous natural gas evaporated gas during operation. The compressor 20 is connected to the storage device 10 and can compress the natural gas evaporated gas. The natural gas evaporated gas is compressed by the compressor 20 to form a high-pressure gas with an increased liquefaction temperature, and the gas temperature is increased. The heat exchanger 30 is provided with a first heat exchange chamber and a second heat exchange chamber spaced apart from each other. The high-pressure gas compressed by the compressor 20 will enter the first heat exchange chamber. The gas supply pipeline 40 is connected to the storage device 10 and the second heat exchange chamber. When the gas supply is working, the natural gas of the storage device 10 is supplied to the second heat exchange chamber through the gas supply pipeline 40. The natural gas temperature in the second heat exchange chamber is lower than that in the first heat exchange chamber, and will absorb the gas in the first heat exchange chamber. The heat of the high-pressure gas, since the temperature of the natural gas in the second heat exchange chamber is lower than the temperature required for liquefaction of the high-pressure gas in the first heat exchange chamber, causes the high-pressure gas in the first heat exchange chamber to liquefy under heat exchange with the natural gas in the second heat exchange chamber to form liquid natural gas. The return liquid pipeline 50 is connected to the first heat exchange chamber and the storage device 10, and can re-enter the liquid natural gas formed in the first heat exchange chamber into the storage device 10 for storage. The gas supply component 60 is connected to the second heat exchange chamber, and can supply the natural gas heated in the second heat exchange chamber to the gas-consuming equipment 10a of the ship for use by the gas-consuming equipment 10a. The above gas supply method formed by the gas supply system can, during the gas supply to the gas-consuming equipment 10a, make use of the natural gas's own coldness and cooperate with the compression of the natural gas boil-off by the compressor 20 to re-liquefy the natural gas boil-off, which can significantly reduce the energy consumption required for liquefying the natural gas boil-off, thereby reducing the gas supply cost of the liquefied natural gas supply system.

[0058] In this embodiment, the gas-consuming equipment 10a may be a generator, a boiler or other equipment.

[0059] In this embodiment, the natural gas boil-off is compressed by compressor 20 to a pressure of 16 bar (or other suitable pressure). At this point, the temperature required for liquefaction of the natural gas boil-off only needs to be below -113°C. The temperature of natural gas at atmospheric pressure is approximately -140°C. Therefore, the compressed natural gas can be liquefied by exchanging heat between the atmospheric pressure natural gas and the compressed natural gas, thereby utilizing the natural gas's inherent cooling capacity.

[0060] It can be understood that the storage device 10 can be any storage device that can store liquefied natural gas, such as a storage tank or a storage cabin, and the number of the storage device 10 can be one or more.

[0061] In some embodiments, as Figure 1As shown, the storage device 10 is provided with a first storage chamber 11 and a second storage chamber 12, which are used to store natural gas. The compressor 20 and the return liquid pipeline 50 are both connected to the first storage chamber 11. The gas supply pipeline 40 includes a first gas supply pipe 41, and the two ends of the first gas supply pipe 41 are respectively connected to the second heat exchange chamber and the second storage chamber 12, which is used to supply the natural gas evaporated gas in the second storage chamber 12 to the second heat exchange chamber.

[0062] Specifically, during the natural gas supply process, the natural gas boil-off in the first storage chamber 11 can be compressed by the compressor 20 and heat exchanged in the heat exchanger 30 to form liquefied natural gas, and finally flow back to the first storage chamber 11. Therefore, the first storage chamber 11 will serve as a chamber for storing liquefied natural gas, and the amount of natural gas stored therein remains unchanged. The natural gas in the second storage chamber 12 will enter the heat exchanger 30 through the gas supply pipeline 40, and after heat exchange in the heat exchanger 30, it will be supplied to the gas-consuming equipment 10a via the gas supply component 60, so that the natural gas in the second storage chamber 12 will serve as the gas supply chamber for gas supply. Through the above arrangement, the first storage chamber 11 can be used as a chamber for storing natural gas, and the second storage chamber 12 can be used as a chamber for gas supply, so that the natural gas supply and natural gas boil-off can be carried out through two separate chambers. Since the temperature of the refluxed liquefied natural gas is different from the temperature of the natural gas in the storage chamber, the interference of the refluxed natural gas on the natural gas supply can be avoided, thereby improving the stability of the system.

[0063] Since the second storage chamber 12 also contains a large amount of natural gas boil-off, the gas supply pipeline 40 is provided with a first gas supply pipe 41, which can supply the natural gas boil-off from the second storage chamber 12 to the second heat exchange chamber for heat exchange in the heat exchanger 30, thereby reducing the amount of gaseous natural gas in the second storage chamber 12. After heat exchange in the heat exchanger 30, the gaseous natural gas is finally supplied to the gas-consuming equipment 10a through the gas supply assembly 60.

[0064] In this embodiment, Figure 1 As shown, the storage device 10 includes two storage compartments. When used on a ship, the two storage compartments are respectively arranged at the bow and stern of the ship, and the first storage cavity 11 and the second storage cavity 12 are respectively arranged in the two storage compartments, so that the first storage cavity 11 and the second storage cavity 12 do not interfere with each other.

[0065] In this embodiment, Figure 1 As shown, the first storage chamber 11 and the first heat exchange chamber are connected by a ventilation pipe 13, and the compressor 20 is installed in the ventilation pipe 13. The ventilation pipe 13 is also provided with two first manual control valves 131 and a first remote control valve 132. The first remote control valve 132 is close to the first storage chamber 11, and the two first manual control valves 131 are respectively located on both sides of the compressor 20. During the air supply period, the first remote control valve 132 and the two first manual control valves 131 are in a normally open state.

[0066] In this embodiment, Figure 1 As shown, one end of the first gas supply pipe 41 connected to the second storage chamber 12 is located on the upper side of the second storage chamber 12. Since the gaseous natural gas will mainly gather on the upper side of the cavity, by arranging the first gas supply pipe 41 on the upper side of the second storage chamber 12, the gaseous natural gas in the second storage chamber 12 can be effectively supplied to the second heat exchange chamber.

[0067] In this embodiment, Figure 1 As shown, the first gas supply pipe 41 is provided with a second manual control valve 411 , and when the natural gas boil-off gas in the second storage chamber 12 is sufficient, the second manual control valve 411 is opened.

[0068] As the total amount of liquefied natural gas in the second storage chamber 12 decreases, the generated natural gas boil-off gas will also decrease accordingly. In order to avoid the amount of natural gas boil-off gas being insufficient to liquefy the natural gas boil-off gas supplied from the first storage tank, in some embodiments, such as Figure 1 As shown, the gas supply pipeline 40 also includes a second gas supply pipe 42, the two ends of which are respectively connected to the second heat exchange chamber and the second storage chamber 12. The second gas supply pipe 42 is provided with a gas pump, which is located in the second storage chamber 12 and is used to drive the liquefied natural gas in the second storage chamber 12 to the second heat exchange chamber.

[0069] Specifically, when the amount of natural gas boil-off gas (BOG) in the second storage chamber 12 is low (e.g., only half of what it would be if the tank were full), the reduced amount of low-temperature BOG (the cooling energy it provides) is insufficient to cool the high-temperature, high-pressure BOG in the first heat exchange chamber to a liquefied state. The second manual control valve 411 is closed, and the gas pump in the second storage chamber 12 is activated. The liquefied natural gas (LNG) in the second storage chamber 12 enters the second heat exchange chamber through the second gas supply pipe 42, exchanging heat with the high-temperature, high-pressure BOG in the first heat exchange chamber. This ensures that the BOG in the first storage chamber 11 is converted into LNG. The LNG, after being heated by the low-temperature heat exchanger 30, is then supplied to the gas-consuming device 10a for consumption. This prevents the storage capacity of the LNG in the first storage chamber 11 from being reduced due to the intrusion of ambient heat during transportation.

[0070] In this embodiment, Figure 1 As shown, the second gas supply pipe 42 is provided with a third manual control valve 421 . Before starting the gas pump, the second manual control valve 411 must be closed and the third manual control valve 421 must be opened.

[0071] As the natural gas in the second storage chamber 12 continues to be used, the amount of liquid natural gas in the second storage chamber 12 gradually decreases. In order to prevent the gaseous natural gas and liquid natural gas in the second storage chamber 12 from being unable to provide the cooling capacity required for liquefying the natural gas vapor in the first heat exchange chamber, in some embodiments, such as Figure 1 As shown, the gas supply pipeline 40 also includes a third gas supply pipe 43, the ends of which are connected to the first heat exchange chamber and the second storage chamber 12, respectively. This pipe is used to supply natural gas from the first heat exchange chamber to the second heat exchange chamber. Specifically, when the amount of liquefied natural gas in the second storage chamber 12 is insufficient to provide the cooling capacity required to liquefy the boil-off gas in the first heat exchange chamber, the third manual control valve 421 is closed, allowing some boil-off gas from the first storage chamber 11 to enter the second storage chamber 12 through the third gas supply pipe 43. There, it exchanges heat with the compressed boil-off gas in the first storage chamber 11, liquefying the compressed boil-off gas.

[0072] In this embodiment, Figure 1 As shown, the third air supply pipe 43 is provided with a fourth manual control valve 431 . When air is supplied through the third air supply pipe 43 , the third manual control valve 421 must be closed first and the fourth manual control valve 431 must be opened.

[0073] In this embodiment, Figure 1 As shown, one end of the third gas supply pipe 43 connected to the first storage chamber 11 is connected to the ventilation pipe 13, and the other end connected to the second heat exchange chamber is connected to the first gas supply pipe 41. When the fourth manual control valve 431 is opened, part of the natural gas evaporated gas entering the ventilation pipe 13 will enter the compressor 20 and be compressed by the compressor 20, and the other part of the natural gas evaporated gas will enter the second storage chamber 12 through the third gas supply pipe 43 to exchange heat with the natural gas evaporated gas compressed in the first storage chamber 11.

[0074] In this embodiment, in order to replenish the amount of natural gas in the second storage chamber 12 in time, Figure 1 As shown, the storage device 10 is further provided with a liquid replenishing tube 14, the two ends of which are connected to the first storage chamber 11 and the second storage chamber 12. The liquid replenishing tube 14 is equipped with a replenishing pump 141 and a second remote control valve 142. The replenishing pump 141 is located in the first storage chamber 11. When the amount of liquid natural gas in the second storage chamber 12 is too low, the second remote control valve 142 is opened, and the replenishing pump 141 is started to supply the liquid natural gas in the first storage chamber 11 into the second storage chamber 12 through the liquid replenishing tube 14, thereby replenishing the liquid natural gas in the second storage chamber 12.

[0075] In some embodiments, as Figure 1As shown, the liquid return line 50 includes a first liquid return line 51 and a second liquid return line 52. One end of the first liquid return line 51 and the second liquid return line 52 are connected to the first storage chamber 11, and the other ends of the first liquid return line 51 and the second liquid return line 52 are connected to the first storage chamber 11 and the second storage chamber 12, respectively. Specifically, the liquefied natural gas formed by liquefaction in the first heat exchange chamber can be passed into the first storage chamber 11 through the first liquid return line 51 and / or into the second storage chamber 12 through the second liquid return line 52.

[0076] In this embodiment, Figure 1 As shown, both ends of the first liquid return pipe 51 are connected to the first heat exchange chamber and the first storage chamber 11, and both ends of the second liquid return pipe 52 are connected to the first liquid return pipe 51 and the second storage chamber 12. A fifth manual control valve 511 is provided at the end of the first liquid return pipe 51 close to the heat exchanger 30, and a third remote control valve 512 is provided at the end close to the first storage chamber 11. A fourth remote control valve 521 is provided at the end of the second liquid return pipe 52 close to the second storage chamber 12. Spray nozzles are provided at the ends of the first liquid return pipe 51 and the second liquid return pipe 52 connecting the first storage chamber 11 and the second storage chamber 12.

[0077] When the amount of liquefied natural gas in the first storage chamber 11 is sufficient, the third remote-controlled valve 512 is opened and the fourth remote-controlled valve 521 is closed. The liquefied natural gas is then completely passed into the first storage chamber 11 via the first liquid return pipe 51. When the second storage chamber 12 begins to be supplied with liquefied natural gas from its interior, the third remote-controlled valve 512 is opened and the fourth remote-controlled valve 521 is opened. Part of the liquefied natural gas is passed into the first storage chamber 11 via the first liquid return pipe 51, while the remaining part is passed into the second storage chamber 12 via the second liquid return pipe 52. When the amount of liquefied natural gas in the second storage chamber 12 is low, the third remote-controlled valve 512 is closed and the fourth remote-controlled valve 521 is opened. The liquefied natural gas is completely passed into the second storage chamber 12 via the second liquid return pipe 52, thereby promptly replenishing the liquefied natural gas in the second storage chamber 12.

[0078] In order to achieve a balance between the amount of gaseous natural gas and liquid natural gas in the second storage chamber 12, in some embodiments, as shown in FIG. Figure 1As shown, the liquefied natural gas supply system also includes a liquefaction pipeline 70 and a vaporization pipeline 80. Both ends of the liquefaction pipeline 70 and the vaporization pipeline 80 are connected to the storage device 10. The liquefaction pipeline 70 is provided with a cryogenic cooler 71 for liquefying the natural gas evaporated gas of the storage device 10 through the cryogenic cooler 71. The vaporization pipeline 80 is provided with a vaporizer 81 for vaporizing the liquid natural gas of the storage device 10 through the vaporizer 81. Specifically, when the amount of natural gas boil-off gas in the second storage chamber 12 is excessive, so that the amount of natural gas boil-off gas exceeds the gas demand of the gas-consuming device 10a, the cryogenic cooler 71 is activated to lower the temperature of the natural gas and then re-introduce it into the second storage chamber 12, thereby reducing the amount of natural gas boil-off gas in the second storage chamber 12; when the amount of natural gas boil-off gas in the second storage chamber 12 is too small to be used by the gas-consuming device 10a, the vaporizer 81 is activated to vaporize part of the natural gas in the second storage chamber 12 and then re-introduce it into the second storage chamber 12, thereby increasing the amount of natural gas boil-off gas in the second storage chamber 12 for use by the gas-consuming device 10a, thereby controlling the balance between liquid natural gas and gaseous natural gas in the second storage chamber 12.

[0079] In this embodiment, Figure 1 As shown, one end of the liquefaction pipeline 70 is connected to the liquid infusion pipe 14 and the other end is connected to the second liquid return pipe 52. One end of the vaporization pipeline 80 is connected to the liquid infusion pipe 14 and the other end is connected to the first gas supply pipe 41. The storage device 10 also includes a liquid pump connected to the liquid infusion pipe 14. When the amount of natural gas evaporation in the second storage chamber 12 needs to be reduced, the liquid pump drives the natural gas to the liquid infusion pipe 14. The natural gas then enters the liquefaction pipeline 70 from the liquid infusion pipe 14, is cooled by the cryocooler 71 of the liquefaction pipeline 70, and then flows back to the second storage chamber 12 through the second liquid return pipe 52. When the amount of natural gas evaporation in the second storage chamber 12 needs to be increased, the liquid pump drives the natural gas to the liquid infusion pipe 14. The natural gas then enters the vaporization pipeline 80 from the liquid infusion pipe 14, is vaporized by the vaporizer 81 of the vaporization pipeline 80, and then flows back to the second storage chamber 12 through the first gas supply pipe 41, thereby controlling the balance between the liquid and gaseous natural gas in the second storage chamber 12.

[0080] In some embodiments, as Figure 1 As shown, the gas supply assembly 60 includes a pressurized pipeline 61 and a heating pipeline 62, which are arranged in parallel. One end of the pressurized pipeline 61 and the heating pipeline 62 is connected to the second heat exchange chamber, and the other end of the pressurized pipeline 61 and the heating pipeline 62 is used to connect to the gas-consuming equipment 10a.

[0081] like Figure 1 As shown, the pressurizing pipeline 61 is provided with a compressor 611, and the compressor 611 is used to pressurize the natural gas supplied to the gas-consuming equipment 10a.

[0082] like Figure 1As shown, heating pipeline 62 is equipped with a heater 621, which is used to heat and vaporize the gas supplied to gas-consuming device 10a. Specifically, when the natural gas supplied to the second heat exchange chamber is boil-off gas from the first storage chamber 11 or the second storage chamber 12, the boil-off gas, after heat exchange, enters the pressurization pipeline 61. The boil-off gas is pressurized by compressor 611 before being supplied to gas-consuming device 10a. When the natural gas supplied to the second heat exchange chamber is liquefied natural gas from the second storage chamber 12, the liquefied natural gas, after heat exchange, enters the heating pipeline 62. The liquefied natural gas is heated and vaporized by heater 621 before being supplied to gas-consuming device 10a, thereby adapting the gas supply to the first storage chamber 11 and the second storage chamber 12.

[0083] In this embodiment, Figure 1 As shown, the pressurized pipeline 61 is further provided with a first buffer tank 612 . Natural gas evaporated gas enters the first buffer tank 612 for temporary storage and then enters the compressor 611 for compression.

[0084] In this embodiment, Figure 1 As shown, the gas supply component 60 also includes a second buffer tank 63, which is connected to the pressurized pipeline 61 and the heating pipeline 62. After the natural gas is pressurized and gasified through the pressurized pipeline 61 and the heating pipeline 62, it is passed into the second buffer tank 63 and finally supplied to the gas-consuming equipment 10a through the second buffer tank 63.

[0085] In this embodiment, Figure 1 As shown, the gas supply system further includes a cargo loading and unloading station 90 and a refueling station 100 . The cargo loading and unloading station 90 and the refueling station 100 are connected to the first storage chamber 11 and the second storage chamber 12 . The first storage chamber 11 is provided with a cargo pump 15 .

[0086] The cargo loading and unloading station 90 loads liquefied natural gas into the first storage chamber 11 and the second storage chamber 12 through a liquid phase pipeline, and transports the natural gas boil-off generated in the first storage chamber and the second storage chamber 12 to the shore station through a gas phase pipeline.

[0087] When a dual-fuel ship needs to be refueled with dual fuel, the liquefied natural gas in the first storage chamber 11 and the second storage chamber 12 is driven by the cargo pump 15 to be refueled to the receiving ship, and the gas phase pipeline transports the generated boil-off gas back to the first storage chamber 11 and the second storage chamber 12 to maintain the pressure of the storage tank.

[0088] The present application also provides a method for supplying liquefied natural gas. Figure 2 As shown, the following steps are included:

[0089] S101 , supplying the natural gas in the storage device 10 into the second heat exchange chamber of the heat exchanger 30 , and supplying the evaporated natural gas into the compressor 20 .

[0090] S102 : The compressor 20 compresses the natural gas boil-off gas into high-pressure fuel gas, and supplies the high-pressure fuel gas into the first heat exchange chamber of the heat exchanger 30 .

[0091] S103 , the high-pressure gas in the first heat exchange chamber exchanges heat with the natural gas in the second heat exchange chamber to form liquefied natural gas.

[0092] S104 , the liquefied natural gas formed in the first heat exchange chamber is returned to the storage device 10 through the liquid return pipeline 50 , and the natural gas in the second heat exchange chamber is supplied to the gas-consuming equipment 10 a through the gas supply assembly 60 .

[0093] Specifically, through the above gas supply method, during the gas supply to the gas-consuming equipment 10a, the natural gas boil-off gas can be re-liquefied by utilizing the natural gas's own cooling capacity and cooperating with the compressor 20 to compress the natural gas boil-off gas. This can significantly reduce the energy consumption required for liquefying the natural gas boil-off gas, thereby reducing the gas supply cost of the liquefied natural gas supply system.

[0094] In some embodiments, the storage device 10 supplies natural gas to the second heat exchange chamber of the heat exchanger 30, including:

[0095] The boil-off gas of natural gas in the second storage chamber 12 is supplied to the second heat exchange chamber through the first gas supply pipe 41 .

[0096] When the amount of natural gas boil-off in the second storage chamber 12 is insufficient, the gas pump passes the liquefied natural gas in the second storage chamber 12 into the second heat exchange chamber through the second gas supply pipe 42 .

[0097] When the amount of liquefied natural gas in the second storage chamber 12 is insufficient, the natural gas in the first storage chamber 11 is supplied to the second heat exchange chamber through the third gas supply pipe 43 .

[0098] Specifically, through the above gas supply, corresponding gas supply forms can be provided for various states of the natural gas in the second storage chamber 12, thereby ensuring the stability of the gas supply system and enabling the natural gas itself to provide cold energy for the liquefaction of the natural gas boil-off.

[0099] In this embodiment, the first remote control valve 132 and the two first manual control valves 131 are in a normally open state.

[0100] When the amount of natural gas boil-off gas in the second storage chamber 12 is sufficient, the second manual control valve 411 is opened, and the natural gas boil-off gas in the second storage chamber 12 is supplied to the second heat exchange chamber through the first gas supply pipe 41. After heat exchange in the second heat exchange chamber, the natural gas boil-off gas enters the pressurized pipeline 61, is pressurized by the compressor 611 of the pressurized pipeline 61, and is then supplied to the gas-consuming equipment 10a.

[0101] When the amount of natural gas boil-off in the second storage chamber 12 is low, the second manual control valve 411 is closed and the gas pump in the second storage chamber 12 is started, allowing the liquefied natural gas in the second storage chamber 12 to enter the second heat exchange chamber through the second gas supply pipe 42. The liquefied natural gas after heat exchange in the second heat exchange chamber will enter the heating pipeline 62, be heated and vaporized by the heater 621 of the heating pipeline 62, and then be supplied to the gas-consuming equipment 10a.

[0102] When the amount of liquefied natural gas in the second storage chamber 12 is unable to provide the cooling capacity required to liquefy the natural gas boil-off gas in the first heat exchange chamber, the third manual control valve 421 is closed, and the second manual control valve 411 and the fourth manual control valve 431 are opened. The natural gas boil-off gas in the second storage chamber 12 and part of the natural gas boil-off gas in the first storage chamber 11 enter the second storage chamber 12 through the third gas supply pipe 43. After heat exchange in the second heat exchange chamber, the natural gas boil-off gas enters the pressurized pipeline 61, is pressurized by the compressor 611 of the pressurized pipeline 61, and is then supplied to the gas-consuming equipment 10a.

[0103] In some embodiments, the liquefied natural gas in the first heat exchange chamber is returned to the storage device 10 through the liquid return line 50, including:

[0104] Part of the liquefied natural gas flows into the first storage chamber 11 through the first liquid return pipe 51, while the remaining part flows into the second storage chamber 12 through the second liquid return pipe 52. Specifically, when the amount of liquefied natural gas in the first storage chamber 11 is sufficient, the third remote-controlled valve 512 is opened and the fourth remote-controlled valve 521 is closed, allowing the liquefied natural gas to flow entirely into the first storage chamber 11 through the first liquid return pipe 51. When the second storage chamber 12 begins to be supplied with liquefied natural gas from within, the third remote-controlled valve 512 and the fourth remote-controlled valve 521 are opened, allowing part of the liquefied natural gas to flow into the first storage chamber 11 through the first liquid return pipe 51, while the remaining part flows into the second storage chamber 12 through the second liquid return pipe 52. When the amount of liquefied natural gas in the second storage chamber 12 is low, the third remote-controlled valve 512 is closed and the fourth remote-controlled valve 521 is opened, allowing the liquefied natural gas to flow entirely into the second storage chamber 12 through the second liquid return pipe 52, thereby promptly replenishing the liquefied natural gas in the second storage chamber 12.

[0105] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0106] It should be understood that the present application is not limited to the exact structure described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A liquefied natural gas supply system, characterized in that: include: a storage device for storing natural gas; a compressor, connected to the storage device, for compressing the natural gas boil-off gas generated by the storage device to form high-pressure fuel gas from the natural gas boil-off gas; A heat exchanger is provided with a first heat exchange chamber and a second heat exchange chamber spaced apart from each other, wherein the first heat exchange chamber is communicated with the compressor and is used to receive the high-pressure gas generated by the compressor; a gas supply pipeline in communication with the storage device and the second heat exchange chamber, for supplying the natural gas from the storage device to the second heat exchange chamber, so as to convert the high-pressure gas in the first heat exchange chamber into liquefied natural gas by heat exchange with the high-pressure gas in the first heat exchange chamber; a liquid return pipeline, communicating with the first heat exchange chamber and the storage device, and configured to pass the liquefied natural gas in the first heat exchange chamber into the storage device; The gas supply component is communicated with the second heat exchange chamber and is used to supply the natural gas in the second heat exchange chamber to the gas-consuming equipment.

2. The liquefied natural gas supply system according to claim 1, characterized in that: The storage device is provided with a first storage chamber and a second storage chamber, the first storage chamber and the second storage chamber are used to store natural gas, the compressor and the liquid return pipeline are both connected to the first storage chamber, and the gas supply pipeline includes a first gas supply pipe, the two ends of which are respectively connected to the second heat exchange chamber and the second storage chamber, and are used to supply the natural gas boil-off gas in the second storage chamber to the second heat exchange chamber.

3. The liquefied natural gas supply system according to claim 2, characterized in that: The gas supply pipeline also includes a second gas supply pipe, the two ends of which are respectively connected to the second heat exchange chamber and the second storage chamber. The second gas supply pipe is provided with a gas pump, which is located in the second storage chamber and is used to drive the liquefied natural gas in the second storage chamber to the second heat exchange chamber.

4. The liquefied natural gas supply system according to claim 2, characterized in that: The gas supply pipeline further includes a third gas supply pipe, both ends of which are respectively connected to the first heat exchange chamber and the second storage chamber, for supplying the natural gas in the first heat exchange chamber into the second heat exchange chamber.

5. The liquefied natural gas supply system according to claim 2, characterized in that: The liquid return pipeline includes a first liquid return pipe and a second liquid return pipe, one end of the first liquid return pipe and the second liquid return pipe are connected to the first storage chamber, and the other end of the first liquid return pipe and the second liquid return pipe are connected to the first storage chamber and the second storage chamber respectively.

6. The liquefied natural gas supply system according to claim 2, characterized in that: It also includes a liquefaction pipeline and a gasification pipeline, both ends of which are connected to the second storage chamber. The liquefaction pipeline is provided with a cryogenic refrigerator for liquefying the natural gas boil-off gas of the storage device through the cryogenic refrigerator, and the gasification pipeline is provided with a gasifier for gasifying the liquid natural gas of the storage device through the gasifier.

7. The liquefied natural gas supply system according to any one of claims 1 to 6, characterized in that: The gas supply assembly includes a pressurizing pipeline and a heating pipeline, the pressurizing pipeline and the heating pipeline are arranged in parallel, one end of the pressurizing pipeline and the heating pipeline is connected to the second heat exchange cavity, and the other end of the pressurizing pipeline and the heating pipeline is used to connect to the gas-consuming equipment; The pressurizing pipeline is provided with a compressor, and the compressor is used to pressurize the natural gas supplied to the gas-consuming equipment; The heating pipeline is provided with a heater, and the heater is used to heat and gasify the gas supplied to the gas-consuming equipment.

8. A liquefied natural gas supply method, characterized in that: The following steps are involved: Supplying the natural gas in the storage device into the second heat exchange chamber of the heat exchanger, and supplying the natural gas boil-off gas into the compressor; The compressor compresses the natural gas vapor into high-pressure fuel gas, and supplies the high-pressure fuel gas into the first heat exchange chamber of the heat exchanger; The high-pressure gas in the first heat exchange chamber exchanges heat with the natural gas in the second heat exchange chamber to form liquefied natural gas; The liquefied natural gas formed in the first heat exchange chamber is returned to the storage device through the liquid return pipeline, and the natural gas in the second heat exchange chamber is supplied to the gas-consuming equipment through the gas supply component.

9. The liquefied natural gas supply method according to claim 8, characterized in that: The storage device supplies natural gas into the second heat exchange chamber of the heat exchanger, comprising: supplying the boil-off gas of natural gas in the second storage chamber into the second heat exchange chamber through the first gas supply pipe; When the amount of natural gas boil-off in the second storage chamber is insufficient, the gas pump passes the liquefied natural gas in the second storage chamber into the second heat exchange chamber through the second gas supply pipe; When the amount of liquefied natural gas in the second storage chamber is insufficient, the natural gas in the first storage chamber is supplied to the second heat exchange chamber through the third gas supply pipe.

10. The liquefied natural gas supply method according to claim 8, characterized in that: The liquefied natural gas in the first heat exchange chamber is returned to the storage device through a liquid return pipeline, including Part of the liquefied natural gas flows into the first storage chamber through the first liquid return pipe, and another part of the liquefied natural gas flows into the second storage chamber through the second liquid return pipe.

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