LNG (Liquefied Natural Gas) fuel filling method and system for LNG power-driven ship

Abstract

The invention discloses an LNG fuel filling method and system for an LNG power-driven ship. The LNG fuel filling system comprises a gas-phase header pipe connected with a gas-phase high-pressure quick connector end, a liquid-phase header pipe connected with a liquid-phase high-pressure quick connector end and a liquid distribution header pipe. In the BOG treatment and recycling system connecting end, an inlet header pipe of a BOG compressor is connected with a gas phase header pipe, an outlet of the BOG compressor is connected with a liquid distribution header pipe, a gas return arm / gas return header pipe of the outlet of the compressor is connected with the gas phase header pipe, and an emergency BOG bypass line is connected with a top injection pipe; the high-pressure vaporizer is connected with the liquid-phase header pipe; a high-pressure pump, a top injection pipe, a bottom injection pipe, a top spraying ring, a top air pipe and an emptying mast are arranged in the fuel tank; the components are connected with a gas phase header pipe, a liquid phase header pipe, a liquid distribution header pipe and the like through pipelines and valves, and regulation and control of the inerting process, the open replacement process, the closed replacement process, the initial cooling process, the liquid nitrogen initial cooling process, the filling process, the standing nitrogen purging process and the sailing gas supply process are achieved through on-off regulation of the valves on the pipelines.

Description

Technical Field

[0001] This invention relates to the field of liquefied natural gas (LNG) fuel supply technology, and in particular to an LNG fuel refueling method and system for LNG-powered ships, applicable to the entire process of LNG fuel refueling, cooling, replacement, self-use and loading / unloading of LNG-powered ships in ports or at sea. Background Technology

[0002] The IMO's 2023 Greenhouse Gas Strategy requires that the carbon intensity of international shipping decrease by at least 40% by 2030 compared to 2008, and that net-zero emissions be achieved around 2050. Consequently, the demand for clean, low-carbon fuels for container ships has increased dramatically. Liquefied natural gas (LNG), with its virtually sulfur-free composition, approximately 20% lower carbon emissions per unit of energy compared to traditional heavy fuel oil, and increasing availability, has become the first commercially viable alternative fuel for container ships. With the promotion of LNG-powered ships, LNG refueling has become a crucial link in ensuring their safe, efficient, and green operation.

[0003] For example, invention patent CN112902016A discloses an LNG fuel-powered ship refueling device and method, which uses multiple tank trucks for simultaneous refueling to increase flow rate and reduce waiting time for changing trucks, and combines quick connectors with main valves / branch valves to achieve "plug and play". However, its BOG treatment uses a mobile combustion device for on-site combustion, without nitrogen purging at the refueling termination stage and does not involve zero-emission self-use of BOG during subsequent voyages after refueling.

[0004] Invention patent CN111268026A discloses a system and method for using LNG tank containers as fuel tanks for container ships, which uses standard tank containers as fuel tanks for rapid replacement, but does not disclose the entire process of pre-cooling, replacement, refueling, purging and voyage gas supply, and does not include BOG compression and reuse.

[0005] Therefore, there is an urgent need for an LNG refueling system and method for LNG-powered ships that integrates precooling, inerting, rapid refueling, BOG full recovery, navigation self-use, and termination purging, which can achieve closed-loop management with zero emissions, zero venting during navigation, and dual use for loading and unloading. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this application proposes an LNG refueling method and system for LNG-powered ships. This invention integrates precooling, inerting, rapid refueling, BOG full recovery, navigation self-use, and termination purging into one system, enabling closed-loop management with zero emissions, zero venting during navigation, and dual use for loading and unloading, thus ensuring the safety and efficiency of LNG refueling.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An LNG refueling method for LNG-powered ships includes inerting of gas in the fuel tank, open gas replacement in the fuel tank, closed gas replacement in the fuel tank, initial cooling of the fuel tank, initial liquid nitrogen cooling of the fuel tank, LNG refueling, static nitrogen purging, and switching and regulation of the navigation gas supply. The steps are as follows: S1: Inerting of gas inside the fuel tank; During inerting, the nitrogen supply valve needs to be opened, and dry nitrogen is pumped into the fuel tank from the top to remove the oxygen inside the fuel tank. The fuel tank must be dry, with an oxygen content ≤3% and a dew point temperature < -20℃ to complete the inerting process. S2: Gas replacement in the fuel tank: LNG is supplied from an external source, which is converted into gaseous natural gas through a high-pressure vaporizer. The gas is then injected into the fuel tank through the top, and the original nitrogen in the fuel tank is discharged. When the gaseous natural gas content in the tank reaches 5%, the open replacement is completed. S3: Gas replacement in fuel tank is closed; gaseous natural gas continues to be injected into the fuel tank through the top, and the nitrogen that is replaced is processed by the boiler to complete the closed fine replacement; S4: Initial cooling of the fuel tank; LNG is sprayed out in a mist form through the top spray ring inside the top fuel tank, and evaporates directly in the fuel tank, gradually cooling the fuel tank from room temperature to -130℃, thus completing the initial cooling; S5: LNG refueling in fuel tank; after precooling, LNG is injected into the fuel tank, and at the same time, BOG (Bottled Gas) is returned to the refueling vessel to maintain pressure balance on both sides, thus completing the refueling; S6: Settling nitrogen purging; After refueling is completed, first close the shore valve and let it stand for a period of time until the pressure stabilizes before closing the valve of the ship refueling station. Then, the ship refueling station uses nitrogen to purge the shore to complete the settling nitrogen purging. S7: Switching of navigation gas supply; LNG is extracted from the fuel tank, pressurized by a pump, heated by a high-pressure vaporizer, and then sent to the main engine after pressure regulation. At the same time, naturally evaporated BOG in the fuel tank is compressed and heated and then flows into the gas main pipe. All of it enters the main engine to achieve navigation gas supply.

[0008] Furthermore, liquid nitrogen is used for pre-cooling before the LNG refueling operation begins.

[0009] Furthermore, the liquid nitrogen supply source sprays mist from the top spray ring, which evaporates directly in the fuel tank, gradually cooling the fuel tank from room temperature to ≤-158℃, thus completing the liquid nitrogen precooling.

[0010] Further, check if the methane concentration inside the arm is <0.2% to determine that the nitrogen purging is complete and the zero-residue disassembly is finished.

[0011] Furthermore, during the closed-loop replacement process, when the gaseous natural gas content in the tank reaches 90% and the dew point temperature is <-20℃, the closed-loop replacement is considered complete.

[0012] Furthermore, the ethylene glycol in the high-pressure vaporizer is heated to 20-40°C.

[0013] Furthermore, when the engine load decreases and consumption decreases, excess LNG will be returned through a pressure-regulated return pipeline to prevent excessive pump outlet pressure and pipeline pressure fluctuations, achieving zero methane venting throughout the process.

[0014] An LNG refueling system for LNG-powered ships, comprising: At least one connection end of a refueling station, the connection end of the refueling station including a liquid phase high-pressure quick connector end and a gas phase high-pressure quick connector end; the gas phase high-pressure quick connector end is connected to the gas phase main pipe, and the liquid phase high-pressure quick connector end is connected to the liquid phase main pipe and the liquid distribution main pipe. The BOG evaporative gas treatment and reuse system connection includes the BOG compressor inlet manifold, BOG compressor outlet, compressor outlet return arm / return manifold, emergency BOG bypass line, and high-pressure vaporizer; the BOG compressor inlet manifold is connected to the gas phase manifold, the BOG compressor outlet is connected to the liquid distribution manifold, the compressor outlet return arm / return manifold is connected to the gas phase manifold, the emergency BOG bypass line is connected to the top injection pipe; and the high-pressure vaporizer is connected to the liquid phase manifold. Fuel tank; A high-pressure pump is installed inside the fuel tank, and the high-pressure pump is connected to the liquid phase main pipe and the liquid distribution main pipe respectively through pipelines and valves; Top injection pipe and bottom injection pipe are installed inside the fuel tank, and the top injection pipe and bottom injection pipe are connected to the liquid distribution main pipe through pipelines and valves; A top spray ring is installed inside the fuel tank, and the top spray ring is connected to the liquid distribution main pipe through pipelines and valves; A top gas pipe is installed inside the fuel tank, and the top gas pipe is connected to the gas phase main pipe and the boiler through pipelines and valves; The vent mast is located outside the fuel tank and is connected to the top gas pipe, the gas phase main pipe, and the liquid distribution main pipe via pipelines and valves.

[0015] Furthermore, when multiple refueling stations are connected, the gas phase high-pressure quick connector of each refueling station is connected to the gas phase main pipe, and the liquid phase high-pressure quick connector of each refueling station is connected to the liquid phase main pipe and the liquid distribution main pipe. The beneficial effects of this invention are: This invention proposes an LNG refueling method and system for LNG-powered ships, which integrates precooling, inerting, rapid refueling, BOG full recovery, onboard fuel utilization, and termination purging to ensure safer and more efficient LNG refueling. Simultaneously, nitrogen purging is added for isolation, preventing air backflow and the formation of an explosive mixture. Attached Figure Description

[0016] Figure 1 This refers to the inertization process in this invention.

[0017] Figure 2 This is the open substitution process in this invention.

[0018] Figure 3 This is the closed-loop displacement process in this invention.

[0019] Figure 4 This refers to the initial cooling process in this invention.

[0020] Figure 5 This refers to the initial cooling (liquid nitrogen) process in this invention.

[0021] Figure 6 This describes the injection process in this invention.

[0022] Figure 7 This describes the air supply process for navigation in this invention.

[0023] In the diagram, 1. Connection end of the port side refueling station; 1-1. Liquid phase high-pressure quick connector end; 1-2. Gas phase high-pressure quick connector end; 2. Connection end of the starboard side refueling station; 3. Connection end of the BOG (evaporative gas) treatment and reuse system; 3-1. Inlet manifold of the BOG compressor; 3-2. BOG compressor outlet; 3-3. Return gas arm / return gas manifold of the compressor outlet; 3-4. Emergency BOG bypass line; 3-5. High-pressure vaporizer; 4. Liquid phase manifold; 5. Gas phase manifold; 6. Liquid distribution manifold; 7. Vent mast; 8. Fuel tank; 9. Top injection pipe; 10. Bottom injection pipe; 11. Emergency pump; 12-1. First deep well variable frequency pump; 12-2. Second deep well variable frequency pump; 13. Top spray ring; 14. Top gas pipe. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0025] This invention proposes an LNG fuel refueling system for LNG-powered ships. The system integrates precooling, inerting, rapid refueling, BOG full recovery, navigation self-use, and termination purging, which can ensure safer and more efficient LNG fuel refueling. At the same time, it adds static nitrogen purging and uses nitrogen to isolate and prevent air backflow from forming an explosive mixture.

[0026] refer to Figure 1The system structure includes: port side refueling station connection 1, starboard side refueling station connection 2, BOG (evaporative gas) treatment and reuse system connection 3, fuel tank 8, and connecting pipelines, as detailed below: The port side refueling station connection end 1 and the starboard side refueling station connection end 2 are arranged on the port and starboard sides of the hull, each including two liquid phase high pressure quick connectors 1-1 and one gas phase high pressure quick connector 1-2; wherein, the gas phase high pressure quick connector 1-2 on the port side and the gas phase high pressure quick connector 1-2 on the starboard side are connected through the gas phase main pipe 5; the two liquid phase high pressure quick connectors 1-1 located on the same side of the port / starboard side are connected in parallel through the liquid distribution main pipe 6, and the liquid distribution main pipe 6 is also connected in parallel with the liquid phase main pipe 4.

[0027] The reuse system connection terminal 3 includes the BOG compressor inlet manifold 3-1, the BOG compressor outlet 3-2, the compressor outlet return arm / return manifold 3-3, the emergency BOG bypass line 3-4, and the high-pressure vaporizer 3-5; among which, The BOG compressor inlet manifold 3-1 is connected to the gas phase manifold 5, the BOG compressor outlet 3-2 is connected to the liquid distribution manifold 6, the compressor outlet return arm / return manifold 3-3 is connected to the gas phase manifold 5, the emergency BOG bypass line 3-4 is connected to the top injection pipe 9; the high-pressure vaporizer 3-5 is connected to the liquid phase manifold 4.

[0028] The fuel tank 8 is equipped with a top injection pipe 9, a bottom injection pipe 10, a top gas pipe 14, an emergency pump 11, a first deep well variable frequency pump 12-1, a second deep well variable frequency pump 12-2, and a top spray ring 13. The bottom of the top gas pipe 14 extends to the top of the fuel tank 8, and the top of the top gas pipe 14 is connected to the gas phase main pipe 5 and the emergency BOG bypass line 3-4 via pipelines. The top injection pipe 9 extends to the top of the fuel tank 8, and the bottom injection pipe 10 extends to the bottom of the fuel tank 8. Both the top injection pipe 9 and the bottom injection pipe 10 are connected to the liquid distribution main pipe 6. The top spray ring 13 is located at the top of the fuel tank 8 and is connected to the liquid distribution main pipe 6. The first deep well variable frequency pump 12-1 and the second deep well variable frequency pump 12-2 are both connected to the liquid phase main pipe 4, and the emergency pump 11 is connected to the liquid distribution main pipe 6.

[0029] Valves are installed on all the above-mentioned connecting pipelines. By opening and closing the valves on the pipelines, the inerting process, open displacement process, closed displacement process, initial cooling process, liquid nitrogen cooling process, refueling process, and navigation gas supply process can be controlled.

[0030] More specifically, one or both of the port side refueling station connection end 1 and the starboard side refueling station connection end 2 can be used.

[0031] The following is for reference Figure 1-7Taking an LNG-powered container ship as an example, and focusing on the port side bunkering station (the starboard bunkering station is not in use), this paper details a method for LNG bunkering on LNG-powered ships. The specific process is as follows: 1. Inertization process refer to Figure 1 Close the liquid phase high-pressure quick connector 1-1 at the port side refueling station connection point 1 using the valve, and close the liquid phase main pipe 4. Connect the ship's side nitrogen cylinder group through the gas phase high-pressure quick connector 1-2 on the port side, and pump dry nitrogen into the fuel tank 8 via the gas phase main pipe 5 and the top gas pipe 14. The oxygen in the fuel tank 8 is discharged through the bottom injection pipe 10, the liquid distribution main pipe 6, and the vent mast 7. Sample the oxygen every 5 minutes using the online oxygen analyzer in the fuel tank 8. When the oxygen content meets the standard, inerting is considered complete, the nitrogen valve is closed, and the system enters the replacement waiting state.

[0032] 2. Open Permutation Process like Figure 2 As shown, the bunkering vessel supplies LNG at a low flow rate via a liquid phase arm connected to the high-pressure liquid phase quick connector 1-1 on the port side. The LNG flows through the liquid phase manifold 4 into the high-pressure vaporizer 3-5, whose outlet temperature is 0-5°C. The return gas arm / return gas manifold 3-3 at the compressor outlet injects natural gas into the fuel tank 8 through the sequentially connected gas phase manifold 5 and top gas pipe 14. Simultaneously, nitrogen in the fuel tank 8 is diluted and discharged through the sequentially connected bottom injection pipe 10, liquid distribution manifold 6, and vent mast 7. A natural gas sampling point is located at the bottom of the fuel tank 8. When the natural gas concentration in the fuel tank 8 reaches 5% and stabilizes, the open replacement ends, the vent mast 7 is closed, and the system enters the closed phase.

[0033] Closed displacement process like Figure 3 As shown, when LNG continues to be injected from the liquid phase high-pressure quick connector 1-1 on the port side of the bunkering vessel and the flow rate is increased, the injected LNG is injected into the high-pressure vaporizer 3-5 through the liquid phase manifold 4. After the high-pressure vaporizer 3-5 heats the LNG to 20°C, the return gas arm / return gas manifold 3-3 at the compressor outlet injects the heated natural gas into the fuel tank 8 through the top gas pipe 14. Due to the injection of natural gas, the nitrogen gas originally in the fuel tank 8 is compressed and returns to the port side nitrogen return gas arm through the bottom injection pipe 10, the gas phase manifold 5, and the gas phase high-pressure quick connector 1-2 in sequence. Finally, after the natural gas content in the combustion tank reaches 90% and the dew point temperature is stable at <-20°C, ensuring that the nitrogen gas in the fuel tank is completely purged, the closed-loop replacement is considered complete, and the system enters the cooling waiting stage.

[0034] Initial cooling process like Figure 4The diagram illustrates the process of transferring LNG from a refueling terminal to a container ship. The refueling terminal is connected to the liquid phase high-pressure quick connector 1-1. LNG droplets at -162°C are sprayed into the fuel tank 8 through the sequentially connected liquid distribution manifold 6, liquid phase manifold 4, and top spray ring 13. The droplets evaporate rapidly in the fuel tank, and the temperature inside the tank gradually decreases. The resulting low-temperature BOG flows into the inlet manifold 3-1 of the BOG compressor through the top gas pipe 14 and gas phase manifold 5. After being compressed and heated by the BOG compressor, it is sent to the boiler for combustion. At the same time, the temperature inside the tank cools from room temperature to -130°C, which completes the initial cooling.

[0035] 5. Liquid nitrogen precooling process like Figure 5 As shown, the liquid nitrogen supply source is connected to the liquid phase high-pressure quick connector 1-1. After passing through the connected liquid distribution main pipe 6 and liquid phase main pipe 4, it enters the top spray ring 13. It is sprayed out from the top spray ring 13 in a mist form and sprayed into the fuel tank 8, where it evaporates directly inside the tank. This gradually cools the fuel tank 8 from room temperature to an average temperature ≤ -158℃, with a cooling rate ≤ 3℃ / min, i.e., liquid nitrogen pre-cooling. The cold nitrogen gas generated in the fuel tank 8 is discharged through the top gas pipe 14, gas phase main pipe 5, and vent mast 7, which are connected in sequence.

[0036] It should be noted that liquid nitrogen can be used for pre-cooling before the LNG bunkering vessel arrives, i.e. before the LNG bunkering operation begins. This can quickly and effectively cool the fuel tank and ensure the safety of the pre-cooling process.

[0037] 6. Filling process like Figure 6 As shown, the refueling arm on the refueling vessel is connected to the liquid phase high-pressure quick connector 1-1, allowing for slow injection of LNG at a low flow rate. LNG is injected through the liquid distribution manifold 6 from the top injection pipe 9 and the bottom injection pipe 10. The low flow rate of LNG cools the liquid distribution manifold 6 to -120°C to prevent thermal shock, allowing the LNG injection flow rate to be continuously increased. Simultaneously, the vaporized gas (BOG) in the fuel tank 8 is returned to the refueling vessel via the top gas pipe 14, the vapor phase manifold 5, the vapor phase high-pressure quick connector 1-2, and then through the return gas arm, maintaining pressure balance between the refueling vessel and the fuel tank, thus completing the refueling process.

[0038] 7. Nitrogen purging After refueling is complete, close the shore-side valve while keeping the ship-side valve open. Let it stand for half an hour until the two-phase pressure stabilizes. Then, open the ship-side nitrogen purging valve and purge both the liquid and gas phase arms simultaneously for half an hour until residual liquid and gas return to the refueling return tank. Once purging is complete, close the ship-side valve. Check if the methane concentration in the arms is <0.2% to determine that the nitrogen purging is complete and the zero-residue disassembly is finished.

[0039] 8. Navigation air supply process like Figure 7As shown, during navigation, the LNG in fuel tank 8 is pressurized to 10MPa by the first deep-well variable frequency pump 12-1, and then enters the high-pressure vaporizer 3-5 through the liquid phase main pipe 4. It is then heated to 20-40℃ by ethylene glycol in the high-pressure vaporizer 3-5. Simultaneously, the naturally evaporated BOG in fuel tank 8 enters the inlet main pipe 3-1 of the BOG compressor through the top gas pipe 14 and the gas phase main pipe 5. After compression and heating, it merges with the heated LNG into the same gas header and is all sent to the main engine or boiler. When the engine load decreases and consumption decreases, excess LNG is returned through a pressure-regulated return pipeline to prevent excessive pump outlet pressure and pipeline pressure fluctuations, achieving zero methane venting throughout the entire process.

[0040] In the above embodiments, only the connection end 1 of the port side refueling station is used as an example for explanation. The connection end 2 of the starboard side refueling station can be selected according to the specific situation, or a combination thereof.

[0041] In the above embodiment, the first deep well variable frequency pump 12-1 and the second deep well variable frequency pump 12-2 are connected in parallel, and one of them can be selected or switched to work.

[0042] The above embodiments are only used to illustrate the design concept and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes or modifications made based on the principles and design ideas disclosed in the present invention are within the protection scope of the present invention.

Claims

1. A method for LNG fuel filling of an LNG powered ship, characterized in that, For the realization of fuel tank gas inerting, fuel tank gas open replacement, fuel tank gas closed replacement, fuel tank initial cooling, fuel tank liquid nitrogen initial cooling, fuel tank LNG filling, static nitrogen purging, switching of navigation gas supply; the steps are as follows: S1: fuel tank gas inerting; when inerting, the nitrogen supply valve needs to be opened, dry nitrogen is pumped into the fuel tank (8) from the top, oxygen in the fuel tank (8) is discharged, and the fuel tank (8) is dried, the oxygen content in the tank is ≤3%, and the dew point temperature is <-20℃, and the inerting is completed; S2: fuel tank gas open replacement; LNG is supplied from an external source, gaseous natural gas is formed in the high-pressure gasifier (3-5), and is injected into the fuel tank (8) through the top, and the original nitrogen in the fuel tank (8) is discharged, and the gaseous natural gas content in the tank reaches 5%, and the open replacement is completed; S3: fuel tank gas closed replacement; continue to inject gaseous natural gas into the fuel tank (8) through the top, and the displaced nitrogen is treated by the boiler, and the closed fine replacement is completed; S4: fuel tank initial cooling; LNG is sprayed in mist form through the top fuel tank (8) top spray ring (13), and evaporates directly in the fuel tank (8), gradually cooling the fuel tank (8) from room temperature to -130℃, and the initial cooling is completed; S5: fuel tank LNG filling; after precooling, LNG is injected into the fuel tank (8), and at the same time, the BOG is returned to the filling ship, and the pressure balance on both sides is maintained, and the filling is completed; S6: static nitrogen purging; after filling is completed, the shore valve is closed first, and a period of time is waited, and then the ship filling station valve is closed after the pressure is stable, and then the ship filling station uses nitrogen to blow to the shore, and the static nitrogen purging is completed; S7: switching of navigation gas supply; LNG is extracted from the fuel tank (8), pumped and pressurized, heated by the high-pressure gasifier, and sent into the main engine after pressure regulation, and at the same time, the BOG naturally evaporated in the fuel tank (8) is mixed into the gas main pipe after compression and heating, and all of them are put into the main engine, and the navigation gas supply is realized.

2. An LNG fuel filling system for an LNG powered ship according to claim 1, characterized in that, Before the LNG filling operation starts, liquid nitrogen is used for precooling.

3. The LNG fuel filling system for an LNG powered ship according to claim 1, characterized in that, The liquid nitrogen supply source sprays mist through the top spray ring (13), evaporates directly in the fuel tank (8), gradually cools the fuel tank (8) from room temperature to ≤-158℃, and completes the liquid nitrogen precooling.

4. The method of claim 1, wherein, Detect whether the methane concentration in the arm is <0.2%, judge the end of static nitrogen purging, and complete the zero residual liquid disassembly.

5. The method of claim 1, wherein, During the closed replacement process, when the gaseous natural gas content in the tank reaches 90% and the dew point temperature is <-20℃, it is determined that the closed replacement is completed.

6. A method for LNG fuel filling system of a LNG powered ship according to claim 1, characterized in that, The ethylene glycol in the high-pressure gasifier (3-5) is heated to 20-40℃.

7. A method for LNG fuel filling system of a LNG powered ship according to claim 1, characterized in that, When the engine load decreases and the consumption decreases, the excess LNG will return through the backflow pipeline controlled by the pressure regulation to prevent the pump outlet pressure from being too high and the pipeline pressure from fluctuating, and the whole process realizes zero methane emptying.

8. An LNG fuel filling system for an LNG powered ship, characterized in that, It comprises: The connecting end (1) of at least one filling station, the connecting end (1) of the filling station comprising a liquid-phase high-pressure quick connector end (1-1) and a gas-phase high-pressure quick connector end (1-2); the gas-phase high-pressure quick connector end (1-2) is connected with a gas-phase main pipe (5), and the liquid-phase high-pressure quick connector end (1-1) is connected with a liquid-phase main pipe (4) and a liquid distribution main pipe (6); The connecting end (3) of a BOG evaporation gas treatment and recycling system, comprising an inlet main pipe (3-1) of a BOG compressor, a BOG compressor outlet (3-2), a return gas arm / return gas main pipe (3-3) of the compressor outlet, an emergency BOG bypass line (3-4), and a high-pressure gasifier (3-5); the inlet main pipe (3-1) of the BOG compressor is connected with the gas-phase main pipe (5), the BOG compressor outlet (3-2) is connected with the liquid distribution main pipe (6), the return gas arm / return gas main pipe (3-3) of the compressor outlet is connected with the gas-phase main pipe (5), the emergency BOG bypass line (3-4) is connected with a top filling pipe (9), and the high-pressure gasifier (3-5) is connected with the liquid-phase main pipe (4); A fuel tank (8); A high-pressure pump arranged in the fuel tank (8) and connected with the liquid-phase main pipe (4) and the liquid distribution main pipe (6) through pipelines and valves; A top filling pipe (9) and a bottom filling pipe (10) arranged in the fuel tank (8) and connected with the liquid distribution main pipe (6) through pipelines and valves; A top spraying ring (13) arranged in the fuel tank (8) and connected with the liquid distribution main pipe (6) through pipelines and valves; A top gas pipe (14) arranged in the fuel tank (8) and connected with the gas-phase main pipe (5) and a boiler (3-4) through pipelines and valves; A venting mast (7) arranged outside the fuel tank (8) and connected with the top gas pipe (14), the gas-phase main pipe (5) and the liquid distribution main pipe (6) through pipelines and valves.

9. An LNG fuel filling system for an LNG powered ship according to claim 8, characterized in that, When a plurality of filling stations are arranged, the gas-phase high-pressure quick connector end (1-2) of the connecting end (1) of each filling station is connected with the gas-phase main pipe (5), and the liquid-phase high-pressure quick connector end (1-1) of the connecting end (1) of each filling station is connected with the liquid-phase main pipe (4) and the liquid distribution main pipe (6).

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