High-efficiency filling system for LNG carrier

Abstract

The application provides a high-efficiency filling system for LNG transport ships, and relates to the technical field of ships, which comprises a plurality of LNG storage tanks, a receiving pipe system, a nitrogen generator, a nitrogen liquefier, an LNG recovery tank and a filling pipe system; the receiving pipe system comprises a receiving main pipe and a gas return main pipe which are in communication with the plurality of LNG storage tanks, the nitrogen generator is connected with the nitrogen liquefier, the receiving main pipe is provided with a receiving joint which is in communication with the nitrogen generator, the nitrogen liquefier and the LNG recovery tank respectively, one end of the receiving main pipe which is far away from the receiving joint is in communication with the LNG recovery tank, and one end of the gas return main pipe is in communication with the nitrogen generator and the LNG recovery tank; the filling pipe system comprises a filling hose, a filling hard pipe and a filling joint which are connected in sequence, the filling hard pipe is rotationally connected with the filling joint in a positioning mode, and the filling joint and the receiving joint are detachably connected. The application can realize dry inertization, precooling and gas driving before the transport ship approaches the shore, and only needs to be quickly connected with a filling station after approaching the shore, so that the plurality of LNG storage tanks can be filled at the same time, the filling efficiency is greatly improved, and the filling safety is ensured.

Description

Technical Field

[0001] This invention relates to the field of marine technology, and in particular to a high-efficiency refueling system for LNG carriers. Background Technology

[0002] LNG (liquefied natural gas), as a clean and efficient energy source, is increasingly favored as a fuel. Currently, medium- and long-distance LNG transportation relies on LNG carriers, coastal LNG receiving terminals, and transport vehicles. LNG carriers primarily use several LNG storage tanks to receive, store, and transport LNG. Existing technology mainly involves sequentially filling these tanks at refueling stations. Before refueling, each tank needs to be dried, inerted, pre-cooled, and purged to ensure the safety and purity of the LNG received. Due to the large number of LNG tanks on the carrier, performing these processes sequentially results in extremely slow refueling speeds, significantly delaying transportation time. Furthermore, during this process, the LNG carrier is docked at the shore; if the natural environment is harsh and causes the ship to rock, the connection between the refueling station and the LNG storage tanks can become unstable, potentially leading to LNG leaks and compromising the safety of the refueling process. Summary of the Invention

[0003] The purpose of this invention is to provide an efficient refueling system for LNG carriers, which can perform drying, inerting, pre-cooling and gas removal in advance before the LNG carrier docks. After docking, it only needs to be quickly connected to the refueling station to refuel several LNG storage tanks at the same time, which greatly improves refueling efficiency, ensures refueling safety, and makes reasonable use of the BOG vaporized in the LNG storage tanks, effectively reducing costs and avoiding energy waste.

[0004] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0005] An efficient refueling system for LNG carriers includes a plurality of LNG storage tanks installed on the hull, a receiving pipeline system connected to the LNG storage tanks, a nitrogen generator, a nitrogen liquefaction unit, an LNG recovery tank connected to the receiving pipeline system, and a refueling pipeline system installed at a refueling station and connected to the receiving pipeline system; the plurality of LNG storage tanks are arranged in an array along the length of the hull, and their axes are arranged horizontally along the width of the hull.

[0006] The injection piping system includes an injection main pipe and a return gas main pipe arranged along the length of the hull and located at both ends of the LNG storage tank. Each LNG storage tank is connected to the injection main pipe through an injection branch pipe and to the return gas main pipe through a return gas branch pipe. Each injection branch pipe and return gas branch pipe is equipped with an automatic valve and a manual valve to control their on / off state.

[0007] The nitrogen generator is connected to the nitrogen liquefier. The end of the injection main pipe is provided with an injection connector. The injection connector is connected to the nitrogen generator, the nitrogen liquefier and the LNG recovery tank respectively. The end of the injection main pipe away from the injection connector is also connected to the LNG recovery tank and is provided with a recovery valve. One end of the return gas main pipe is connected to the nitrogen generator and the LNG recovery tank.

[0008] The filling piping system includes a filling hose, a filling rigid pipe, and a filling connector. One end of the filling hose is connected to the filling station, and the other end is connected to the filling rigid pipe. The inner diameter of the filling rigid pipe is larger than the inner diameter of the filling hose. The end of the filling rigid pipe away from the filling hose is rotatably connected to the filling connector. The filling connector and the receiving connector are detachably connected.

[0009] The nitrogen generator, the injection main pipe, the LNG storage tank, and the return gas main pipe form a drying and inerting route, and the nitrogen used for drying and inerting returns to the nitrogen generator through the return gas main pipe.

[0010] The nitrogen generator, nitrogen liquefaction unit, injection main pipe, LNG storage tank, and return gas main pipe form a pre-cooling route, and the nitrogen discharged from the pre-cooling returns to the nitrogen generator through the return gas main pipe.

[0011] The LNG recovery tank, the injection main pipe, the LNG storage tank, and the return gas main pipe form a gas driving route, and the BOG used for gas driving and the nitrogen driven out return to the nitrogen generator through the return gas main pipe.

[0012] The refueling pipeline system, the main refueling pipe, and the LNG storage tank form a refueling route. The BOG generated by vaporization in the LNG storage tank is recovered into the LNG recovery tank through the return gas main pipe. After refueling is completed, the remaining LNG in the main refueling pipe and the branch pipe is recovered into the LNG recovery tank.

[0013] By adopting the above technical solution, during the LNG carrier's journey before docking, the nitrogen generator, nitrogen liquefaction unit, LNG recovery tank, and receiving pipeline system are used to directly dry, inertize, pre-cool, and purge the LNG storage tanks. When the LNG carrier docks, the receiving connector on the receiving main pipe is quickly connected to the refueling connector at the refueling station, allowing LNG to be refueled into several LNG storage tanks simultaneously through the refueling pipeline system and the receiving main pipe, greatly improving refueling efficiency.

[0014] Specifically, the drying and inerting route is activated first. Nitrogen generated by the nitrogen generator enters the LNG storage tank through the injection main pipe to inerte the LNG tank. The nitrogen used for drying and inerting, along with the remaining gases expelled, returns to the nitrogen generator through the return gas main pipe, facilitating its reuse for nitrogen production and preventing direct emissions that pollute the environment. Next, the precooling route is activated. Nitrogen generated by the nitrogen generator enters the nitrogen liquefaction unit to form liquid nitrogen. The liquid nitrogen enters the LNG storage tank through the injection main pipe, cooling the LNG tank and preventing rapid temperature changes during LNG refueling, thus improving refueling safety. The nitrogen vaporized from the liquid nitrogen during precooling returns to the nitrogen generator through the return gas main pipe, facilitating its reuse for nitrogen production. After precooling, the purging route is activated. BOG recovered from the LNG recovery tank enters the LNG storage tank through the injection main pipe, expelling residual nitrogen from the LNG storage tank. The expelled nitrogen and the BOG used for purging both return to the nitrogen generator through the return gas main pipe, facilitating its reuse for nitrogen production.

[0015] During the LNG carrier's journey before docking, the LNG storage tanks undergo drying, inerting, pre-cooling, and purging. Upon docking, the refueling and receiving connectors are quickly connected. LNG from the refueling station is injected into the LNG storage tanks through the refueling pipeline and the receiving main pipe. Simultaneously, multiple LNG storage tanks are refueled via the receiving main pipe and several receiving branch pipes, significantly improving refueling efficiency. During refueling, the BOG generated from the vaporization of the LNG in the storage tanks is recovered into the LNG recovery tank through the return gas main pipe. After refueling, any residual LNG in the receiving main pipe and receiving branch pipes is also recovered into the LNG recovery tank. This allows for the direct use of the recovered BOG for purging the LNG storage tanks in the next refueling cycle. Furthermore, the recovered LNG residue can be vaporized into BOG for purging purposes, effectively reducing costs and avoiding energy waste.

[0016] In addition, the filling piping system includes a filling hose, a filling rigid pipe, and a filling connector. The filling connector facilitates quick connection between the filling piping system and the receiving piping system. The filling hose facilitates the storage of the filling piping system when not filling. The positioning and rotating connection between the filling rigid pipe and the filling connector can play a certain buffering role when there is a pulling between the filling piping system and the receiving piping system, ensuring the safety of filling.

[0017] In summary, this invention integrates LNG storage tanks, receiving piping systems, nitrogen generators, nitrogen liquefaction units, and LNG recovery tanks onto the hull. During the LNG carrier's journey before docking, the LNG storage tanks are pre-dried, inerted, pre-cooled, and purged. After docking, the filling and receiving piping systems are quickly connected via filling and receiving connectors, allowing for filling of multiple LNG tanks through the main and branch pipes, significantly improving filling efficiency. Because the receiving piping system is located on the hull, and the filling rigid pipes and filling connectors are rotatably positioned, it effectively buffers the connection impact caused by hull movement due to natural environmental factors, ensuring filling safety. Simultaneously, the vaporized BOG in the LNG tanks during filling and the residual LNG after filling are collected in the LNG recovery tank for subsequent purging of the LNG tanks, effectively reducing costs and avoiding energy waste.

[0018] Furthermore, the filling connector includes a filling seat connected to the filling rigid pipe and a filling ring connected to the end of the filling seat away from the filling rigid pipe. The receiving connector includes a receiving ring connected to the filling ring and a receiving seat connected to the end of the receiving ring away from the filling ring. The receiving seat is connected to branch pipes that are respectively connected to the nitrogen generator, the nitrogen liquefaction unit and the LNG recovery tank, and each branch pipe is provided with a sub-control valve near the receiving seat.

[0019] The filling ring is provided with a filling valve core that slides along its axis, and the receiving ring is provided with a receiving valve core that slides along its axis. The filling seat is provided with a filling spring that abuts against the filling valve core, and the receiving seat is provided with a receiving spring that abuts against the receiving valve core. Under normal conditions, under the action of the filling spring and the receiving spring, the filling valve core and the receiving valve core respectively block the filling ring and the receiving ring.

[0020] The outer diameter of the filling ring is inserted into one end of the receiving ring at a time equal to the inner diameter of the receiving ring. The end face of the filling ring away from the filling seat has a plurality of receiving rods arranged in a circular array parallel to its axis. The end face of the receiving valve core away from the receiving spring has a plurality of receiving holes that mate with the receiving rods. The outer wall of the receiving rod away from the filling ring has an elastic protruding ring, and the inner wall of the receiving hole has a limiting concave ring that mates with the elastic protruding ring. The receiving ring contains a filling rod arranged along its axis and located on the side of the receiving valve core away from the receiving spring, and the filling rod is located on the axis of the receiving ring.

[0021] When the filling connector and the receiving connector are connected, the filling ring is inserted into the receiving ring, and the receiving rod is inserted into the receiving hole to push the receiving valve core to open the receiving ring. The filling rod abuts against the filling valve core and pushes the filling valve core to open the filling ring.

[0022] By adopting the above technical solution, under normal conditions, the filling spring and the receiving spring act to seal the filling ring and the receiving ring respectively. The branch pipes are controlled by separate control valves on the branch pipes, facilitating switching between inerting, drying, pre-cooling, and gas-expelling operating states of the receiving main pipe. When filling by connecting the filling and receiving connectors, the filling ring is inserted into the receiving ring, and the receiving rod is inserted into the receiving socket. The connection between the receiving rod and the receiving valve core is achieved through the cooperation of the elastic convex ring and the limiting concave ring. Under the pushing action of the receiving rod, the receiving spring is compressed, and the receiving valve core slides open the receiving ring. Simultaneously, under the pushing action of the filling rod, the filling spring is compressed, and the filling valve core slides open the filling ring. This achieves the connection and communication between the filling ring and the receiving ring, facilitating LNG filling. During refueling, if the refueling and receiving pipe systems experience pulling or impact due to environmental factors, the positioning and rotating connection between the refueling rigid pipe and the refueling connector can buffer part of the impact. Additionally, when the refueling ring and receiving ring are pulled, the refueling ring tends to slide out of the receiving ring. The refueling rod pulls the receiving valve core, and with the thrust of the receiving spring, the movement of the receiving valve core is reduced or even blocked from the flow port of the receiving ring. Simultaneously, as the refueling ring moves away from the receiving ring, the refueling valve core and the refueling rod move away from each other. Under the thrust of the refueling spring, the movement of the refueling valve core is reduced or even blocked from the flow port of the refueling ring. In this way, when the refueling and receiving rings are pulled or moved by external influences, the flow port can be effectively adjusted or even closed, thus preventing leakage during refueling and effectively improving refueling safety.

[0023] Furthermore, the outer circumferential wall of the filling ring away from the filling seat is provided with a plurality of magnetic beads in a circular array, and the plurality of magnetic beads are positioned and rolled on the outer wall of the filling ring; the inner wall of the receiving ring is provided with a plurality of rolling grooves that cooperate with the magnetic beads in a circular array, the rolling grooves are parallel to the axis of the receiving ring, and the rolling grooves are embedded with magnetic strips that cooperate with the magnetic beads to attract them.

[0024] By adopting the above technical solution, the rapid positioning and insertion of the filling ring and the receiving ring are achieved through the combined action of the magnetic beads and the rolling groove. The rotation of the magnetic beads can buffer a certain amount of impact force, and the attraction and fixation of the magnetic strip and the magnetic beads, combined with the connection and fixation effect of the elastic protruding ring on the receiving rod and the limiting concave ring inside the receiving hole, improves the insertion and fixation effect of the filling ring and the receiving ring. This prevents the filling ring and the receiving ring from detaching due to the reaction force of LNG flowing out of the filling ring during the filling process, ensuring the stability and safety of the filling process. Furthermore, the rolling installation of the magnetic beads within the rolling groove reduces wear on the magnetic beads, increases their service life, and reduces LNG leakage during filling.

[0025] Furthermore, the outer wall of the filling ring is provided with a plurality of relief grooves corresponding to the magnetic beads in a circumferential array. The relief grooves are provided with ball bearing seats that slide radially along the filling ring. The magnetic beads are positioned and rolled on the corresponding ball bearing seats. A retaining spring is connected between the side of the ball bearing seat away from the magnetic beads and the bottom wall of the relief groove. The retaining spring is arranged radially along the filling ring.

[0026] By adopting the above technical solution, the magnetic beads are positioned and rolled on the ball bearing seat, and the ball bearing seat is slidably installed in the relief groove. Under the action of the clamping spring, the magnetic beads are always in contact with the rolling groove and are attracted and fixed by the magnetic strip. This avoids the magnetic beads from wearing out after long-term use, which affects their fixing and sealing function, and ensures the stability and safety of filling. The structure is simple and the effect is obvious.

[0027] Furthermore, the receiving ring is provided with an elastic support member located between the injection rod and the receiving valve core. The elastic support member includes a plurality of elastic ribs arranged in a circumferential array around the axis of the receiving ring. The plurality of elastic ribs are inclined and their ends away from the injection rod are fixed to the inner wall of the receiving ring. The ends of the plurality of elastic ribs close to the injection rod converge and connect to the end of the injection rod that is close to it. The plurality of elastic ribs are spaced apart from the injection rod.

[0028] By adopting the above technical solution, when the receiving ring and the filling ring are connected by insertion, several elastic ribs in the elastic support member enter the filling ring together with the filling rod, and the elastic ribs abut against the inner wall of the filling ring at the end. Under the elastic support of the elastic ribs, the stability of the insertion of the receiving ring and the filling ring is further improved. The structure is simple and the effect is obvious. In particular, the elastic ribs and the receiving rod are spaced apart to avoid interference between them and affect the pushing effect of the receiving rod on the receiving valve core.

[0029] Furthermore, the hull is equipped with an installation assembly that mates with the filling connector and the receiving connector. The installation assembly includes a mounting base on the hull, the receiving connector being detachably and fixedly mounted on the mounting base, and the filling connector being slidably mounted on the mounting base along the length of the receiving main pipe. The mounting base is provided with a limiting groove along the length of the receiving main pipe, and a ball bearing that mates with the limiting groove is rotatably mounted on the filling base. The ball bearing is rotatably mounted within the limiting groove. A vertically positioned limiting plate that mates with the ball bearing is provided at the end of the limiting groove away from the receiving connector. The lower end of the limiting plate is eccentrically mounted on the mounting base, and its rotation axis is set along the width direction of the limiting groove. An unlocking rod that is slidably mounted within the limiting groove along its length and located on the side of the ball bearing away from the limiting plate is slidably mounted. A transmission assembly connects the limiting plate and the unlocking rod. The mounting base is equipped with a sway sensor, and the sway sensor is communicatively controlled by the transmission assembly.

[0030] By adopting the above technical solution, the receiving connector is normally fixed on the mounting base. When the filling connector and the receiving connector are plugged in, the ball is rolled into the limiting groove, and the limiting plate rotates to a vertically upward position to prevent the ball from sliding out of the limiting groove. During the filling process, when the filling pipeline is pulled between the receiving connector due to the natural environment, the ball rolls in the limiting groove, and the filling ring and the receiving ring slide and adjust first. When the sway sensor detects severe hull swaying caused by the natural environment, necessitating an interruption of refueling, the sway sensor communication control transmission component activates. This component controls the limit plate to rotate vertically downwards, releasing the limit plate's restraint on the rolling ball. Simultaneously, the transmission component drives the unlocking rod to slide along the limit groove, pushing the rolling ball out of the groove. This causes the refueling connector to move as a whole, pulling the refueling ring out of the receiving ring and releasing the connection between the refueling and receiving connectors. Furthermore, the refueling valve core and receiving valve core automatically close the refueling and receiving rings under the action of the refueling and receiving springs, thus interrupting refueling and preventing leaks and safety accidents.

[0031] Furthermore, the transmission assembly includes a deflection motor connected to one end of the rotation shaft of the limiting plate. An unlocking gear coaxial with the deflection motor is mounted on the output shaft of the deflection motor. The side wall of the unlocking rod is provided with an unlocking rack arranged along its length and meshing with the unlocking gear. The sway sensor is communicatively connected to the deflection motor. When the deflection motor drives the limiting plate to rotate from vertically upward to vertically downward, the engagement of the unlocking gear and the unlocking rack drives the unlocking rod to push the ball out of the limiting groove to release the connection between the filling connector and the receiving connector.

[0032] By adopting the above technical solution, when the sway sensor detects severe hull swaying caused by the natural environment, necessitating an interruption of refueling, the sway sensor communication control transmits the deflection motor to work. The deflection motor controls the limit plate to rotate to a vertically downward position, releasing the limit plate's restraining effect on the rolling ball. Simultaneously, the deflection motor drives the unlocking gear to rotate synchronously. Under the meshing action of the unlocking gear and the unlocking rack, the unlocking rack drives the unlocking rod to slide along the limit groove, pushing the rolling ball out of the limit groove. This causes the refueling connector to move as a whole, pulling the refueling ring out of the receiving ring, thus releasing the insertion between the refueling connector and the receiving connector.

[0033] Furthermore, a storage tank is provided between the nitrogen generator and the nitrogen liquefaction unit, and the storage tank is connected to both the nitrogen generator and the nitrogen liquefaction unit; a nitrogen pressure gauge and a nitrogen pressure reducing pipe are connected to the storage tank, and a nitrogen pressure reducing valve is provided on the nitrogen pressure reducing pipe; the nitrogen pressure gauge and the nitrogen pressure reducing valve are connected for communication control; a nitrogen cold insulation cover is provided for the nitrogen liquefaction unit, and a heat insulation layer is provided outside the nitrogen cold insulation cover.

[0034] By adopting the above technical solution, nitrogen is prepared by a nitrogen generator and stored in a storage tank before drying and inerting. During drying and inerting, the nitrogen in the storage tank enters the main injection pipe, thus preventing the nitrogen generator's production rate from falling behind the drying and inerting process and ensuring the continuity and effectiveness of the drying and inerting work. A nitrogen pressure gauge monitors the pressure inside the storage tank in real time to prevent excessive pressure from affecting safety. When the pressure gauge detects excessive pressure, a communication-controlled nitrogen pressure reducing valve opens, releasing a certain amount of nitrogen through the pressure reducing pipe to ensure safety. Furthermore, a nitrogen insulation cover prevents the liquid nitrogen produced by the nitrogen liquefaction unit from vaporizing, and an insulation layer prevents the low temperature of the nitrogen liquefaction unit from causing harm to the surrounding environment and personnel.

[0035] Furthermore, the LNG recovery tank is equipped with a partition plate that divides it into an LNG liquid chamber and a BOG gas chamber, with the LNG liquid chamber located above the BOG gas chamber. The end of the injection main pipe away from the injection connector is connected to the LNG liquid chamber, and the return gas main pipe and the injection connector are connected to the BOG gas chamber. The LNG recovery tank is equipped with an LNG cold insulation cover corresponding to the LNG liquid chamber and a protective cover corresponding to the BOG gas chamber. The upper and lower end faces of the partition plate are equipped with cold insulation layers.

[0036] By adopting the above technical solution, the BOG gas generated by vaporization in the LNG storage tank during the refueling process is recovered into the BOG gas chamber through the return gas main pipe. After refueling, the residual LNG in the receiving main pipe and receiving branch pipe is recovered from the end of the receiving main pipe away from the receiving joint into the LNG liquid chamber for storage in LNG form. This avoids the safety accident caused by excessive pressure in the LNG recovery tank, which is filled with BOG. ​​In particular, the cold insulation layer on the LNG cold insulation cover and the partition plate can reduce the vaporization of LNG into BOG in the LNG liquid chamber, and the protective cover prevents the outer wall of the LNG recovery tank from becoming too cold and affecting safety.

[0037] Furthermore, the BOG gas chamber is connected to a BOG pressure gauge and a BOG pressure reducing pipe, and the BOG pressure reducing pipe is equipped with a BOG pressure reducing valve; the partition plate is equipped with a gas supply pipe that connects the LNG liquid chamber and the BOG gas chamber, and the gas supply pipe is equipped with a speed regulating valve; the BOG pressure gauge is communicatively connected to the BOG pressure reducing valve and the speed regulating valve.

[0038] By adopting the above technical solution, the pressure inside the BOG gas chamber is monitored in real time using a BOG pressure gauge. When the monitored pressure is too high, the communication control opens the BOG pressure reducing valve, and some BOG is discharged through the BOG pressure reducing pipe to prevent excessive pressure inside the BOG gas chamber from affecting safety. When the BOG pressure gauge detects that the pressure inside the BOG gas chamber is too low, indicating insufficient BOG reserve, the communication control deceleration valve opens the gas replenishment pipe. LNG in the LNG liquid chamber enters the BOG gas chamber through the gas replenishment pipe and is vaporized into BOG to supplement the BOG for catalytic gas supply, ensuring the continuous operation and effectiveness of the catalytic gas supply.

[0039] In summary, the present invention has the following beneficial effects:

[0040] 1. This invention integrates LNG storage tanks, receiving pipelines, nitrogen generators, nitrogen liquefaction units, LNG recovery tanks, etc. on the hull. During the LNG carrier's journey before docking, the LNG storage tanks are dried, inertized, pre-cooled, and purged with gas. After docking, the filling and receiving pipelines are quickly connected through the filling and receiving connectors, allowing multiple LNG storage tanks to be filled through the receiving main pipe and receiving branch pipes, greatly improving filling efficiency.

[0041] 2. In this invention, a refueling hose, a refueling rigid pipe, a refueling connector, and a receiving connector are provided, with the refueling rigid pipe and the refueling connector being rotatably connected. The refueling connector includes a refueling seat, a refueling ring, a refueling valve core, a refueling spring, and a receiving rod, etc. The receiving connector includes a receiving seat, a receiving ring, a receiving valve core, a receiving spring, and a refueling rod, etc. The refueling connector and the receiving connector are installed on an installation assembly including a mounting base, a limiting groove, a limiting plate, an unlocking rod, and a sway sensor, etc. When the hull swaying caused by the natural environment brings pulling and impact to the refueling connector and the receiving connector, the refueling ring can slide in the receiving ring first and control the refueling valve core and the receiving valve core to reduce or even block the flow port of the refueling ring and the receiving ring to avoid leakage during the refueling process. When it is necessary to interrupt the refueling, the unlocking rod can quickly drive the refueling connector to disengage from the receiving connector to ensure the safety of the refueling.

[0042] 3. In this invention, by setting up structures such as elastic convex rings, limiting concave rings, magnetic beads, rolling grooves, magnetic strips, and elastic support components, the stability of the connection between the filling joint and the receiving joint is improved, and the reaction force of LNG flowing out of the filling ring during the filling process is avoided, which causes the filling ring and the receiving ring to separate, thus ensuring the stability and safety of the filling.

[0043] 4. In this invention, by setting up an LNG recovery tank, the vaporized BOG in the LNG storage tank during the filling process and the residual LNG in the main and branch pipes after filling are collected and used for the next LNG storage tank purging, which effectively reduces costs and avoids energy waste; and the LNG recovery tank is divided into a BOG gas chamber for storing BOG and an LNG liquid chamber for storing LNG, which avoids the safety accident caused by excessive pressure in the LNG recovery tank if it is full of BOG. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the overall structure of a high-efficiency refueling system for LNG carriers.

[0045] Figure 2 This is a schematic diagram of the structure of an LNG recovery tank in a high-efficiency bunkering system for LNG carriers.

[0046] Figure 3This is a schematic diagram of a refueling connector in a high-efficiency refueling system for LNG carriers.

[0047] Figure 4 This is a schematic diagram of the receiving connector in a high-efficiency refueling system for LNG carriers.

[0048] Figure 5 This is a schematic diagram of the plugging and receiving connectors in the working state of an efficient refueling system for LNG carriers.

[0049] In the diagram, 1. Filling piping system; 11. Filling hose; 12. Filling rigid pipe; 13. Filling connector; 14. Filling seat; 141. Ball bearing; 15. Filling ring; 151. Relief groove; 16. Filling valve core; 17. Filling spring; 18. Receiving rod; 181. Elastic convex ring; 19. Magnetic bead; 191. Ball bearing seat; 192. Clamping spring; 2. Receiving piping system; 21. Receiving main pipe; 21 1. Recovery valve; 22. Injection branch pipe; 23. Main return gas pipe; 24. Return gas branch pipe; 25. Automatic valve; 26. Manual valve; 3. Injection connector; 31. Injection seat; 32. Branch pipe; 321. Control valve; 33. Injection ring; 34. Injection valve core; 341. Injection port; 342. Limiting recess ring; 35. Injection spring; 36. Injection rod; 37. Rolling groove; 38. Magnetic strip; 39. Elastic support component; 391. Elastic rib; 4. Mounting assembly; 41. Mounting base; 42. Limiting groove; 43. Limiting plate; 44. Unlocking rod; 45. Shaking sensor; 5. Transmission assembly; 51. Deflection motor; 52. Unlocking gear; 53. Unlocking rack; 6. LNG storage tank; 7. Nitrogen generator; 71. Storage tank; 72. Nitrogen pressure gauge; 73. Nitrogen pressure reducing pipe; 74. Nitrogen pressure reducing valve; 8. Nitrogen liquefaction unit; 81. Nitrogen cold insulation cover; 82. Insulation layer; 9. LNG recovery tank; 91. Separator plate; 911. Cold insulation layer; 92. LNG liquid chamber; 921. LNG cold insulation cover; 93. BOG gas chamber; 931. Protective cover; 94. BOG pressure gauge; 95. BOG pressure reducing pipe; 951. BOG pressure reducing valve; 96. Gas supply pipe; 961. Speed ​​control valve. Detailed Implementation

[0050] The present 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 only for explaining the present invention and are not intended to limit the present invention.

[0051] A high-efficiency refueling system for LNG carriers, such as Figure 1As shown, the system includes several LNG storage tanks 6, a receiving pipeline system 2 connected to the LNG storage tanks 6, a nitrogen generator 7, a nitrogen liquefier 8, an LNG recovery tank 9 connected to the receiving pipeline system 2, and a refueling pipeline system 1 connected to the receiving pipeline system 2. The LNG storage tanks 6, the receiving pipeline system 2, the nitrogen generator 7, the nitrogen liquefier 8, and the LNG recovery tank 9 are all installed on the LNG transport ship, while the refueling pipeline system 1 is located at the refueling station. The several LNG storage tanks 6 are arranged in an array along the length of the LNG transport ship, with their axes horizontally aligned along the width of the hull. The ship can have several rows, columns, and layers of LNG storage tanks 6, with each row and layer of LNG storage tanks forming a group. Each group corresponds to one receiving pipeline system 2. This embodiment only uses one group of LNG storage tanks 6 as an example.

[0052] like Figure 1 As shown, the injection piping system 2 includes an injection main pipe 21 and a return gas main pipe 23, which are arranged along the length of the hull and located at both ends of the LNG storage tank 6. Each LNG storage tank 6 is connected to the injection main pipe 21 via an injection branch pipe 22 and to the return gas main pipe 23 via a return gas branch pipe 24. Each injection branch pipe 22 and return gas branch pipe 24 is equipped with an automatic valve 25 and a manual valve 26 to control their on / off state. Under normal conditions, the automatic valve 25 controls the on / off state of the corresponding injection branch pipe 22 and return gas branch pipe 24 to connect or disconnect the corresponding LNG storage tank 6 from the injection main pipe 21 and return gas main pipe 23. When the automatic valve 25 malfunctions and cannot work normally, the corresponding manual valve 26 takes over to ensure safety and continuity of operation.

[0053] like Figure 1 As shown, a storage tank 71 is provided between the nitrogen generator 7 and the nitrogen liquefaction unit 8 and is connected to them. The end of the injection main pipe 21 is provided with an injection connector 3. The injection connector 3 is connected to the storage tank 71, the nitrogen liquefaction unit 8 and the LNG recovery tank 9 respectively. The end of the injection main pipe 21 away from the injection connector 3 is also connected to the LNG recovery tank 9 and is provided with a recovery valve 211 for controlling its opening and closing and a recovery pump (not shown in the figure) connected to it. One end of the return gas main pipe 23 is connected to the nitrogen generator 7 and the LNG recovery tank 9.

[0054] Among them, such as Figure 1As shown, a nitrogen pressure gauge 72 and a nitrogen pressure reducing pipe 73 are connected to the storage tank 71. A nitrogen pressure reducing valve 74 is installed on the nitrogen pressure reducing pipe 73. The nitrogen pressure gauge 72 and the nitrogen pressure reducing valve 74 are connected for communication control. The nitrogen pressure gauge 72 monitors the pressure inside the storage tank 71 in real time. When the pressure inside the storage tank 71 is too high, it controls the nitrogen pressure reducing valve 74 to open, releasing a certain amount of nitrogen through the nitrogen pressure reducing pipe 73 to ensure safety. In addition, a nitrogen insulation cover 81 is installed outside the nitrogen liquefaction unit 8 to prevent the liquid nitrogen produced by the nitrogen liquefaction unit 8 from vaporizing. An insulation layer 82 is installed outside the nitrogen insulation cover 81 to prevent the low temperature of the nitrogen liquefaction unit 8 from causing harm to the surrounding environment and personnel.

[0055] like Figure 1 As shown, the refueling pipeline system 1 includes a refueling hose 11, a refueling rigid pipe 12, and a refueling connector 13 connected in sequence. The end of the refueling rigid pipe 12 away from the refueling hose 11 is rotatably connected to the refueling connector 13. The refueling connector 13 and the receiving connector 3 are detachably connected. The inner diameter of the refueling rigid pipe 12 is larger than the inner diameter of the refueling hose 11. In the event of an accidental disconnection between the refueling connector 13 and the receiving connector 3, the refueling rigid pipe 12 can store the LNG delivered by the refueling hose 11, preventing a high-pressure explosion.

[0056] like Figure 1 As shown, this invention integrates LNG storage tanks 6, receiving piping systems 2, nitrogen generators 7, storage tanks 71, nitrogen liquefaction units 8, and LNG recovery tanks 9 onto the ship's hull. During the LNG carrier's journey before docking, the nitrogen generator 7, storage tanks 71, nitrogen liquefaction units 8, LNG recovery tanks 9, and receiving piping systems 2 work together to sequentially dry, inertify, pre-cool, and purge the LNG storage tanks 6. When the LNG carrier docks, the receiving connector 3 on the receiving main pipe 21 is quickly connected to the refueling connector 13 at the refueling station, allowing simultaneous LNG refueling of multiple LNG storage tanks 6 via the refueling piping system 1 and the receiving main pipe 21, significantly improving refueling efficiency. Furthermore, because the receiving piping system 2 is located on the ship's hull, and the refueling rigid pipe 12 and refueling connector 13 are rotatably connected, it effectively buffers the connection impact of ship sway caused by natural environmental factors, ensuring refueling safety.

[0057] Specifically, such as Figure 1As shown, the nitrogen generator 7, storage tank 71, injection pipe 21, LNG storage tank 6, and return gas pipe 23 form a drying and inerting route. During operation, the nitrogen generated by the nitrogen generator 7 enters the LNG storage tank 6 through the storage tank 71, injection connector 3, and injection pipe 21 to inertify the LNG storage tank 6. The nitrogen used for drying and inerting, along with the remaining gases expelled, returns to the nitrogen generator 7 through the return gas pipe 23, facilitating its reuse for nitrogen production and avoiding direct emissions that pollute the environment. The nitrogen generator 7 can begin operation some time before the drying and inerting process begins, storing a certain amount of nitrogen in the storage tank 71 to ensure the continuity of the drying and inerting process.

[0058] like Figure 1 As shown, the nitrogen generator 7, storage tank 71, nitrogen liquefaction unit 8, injection main pipe 21, LNG storage tank 6, and return gas main pipe 23 form a pre-cooling route. After drying and inerting, pre-cooling is performed. The nitrogen generated by the nitrogen generator 7 enters the nitrogen liquefaction unit 8 through the storage tank 71 to form liquid nitrogen. The liquid nitrogen enters the LNG storage tank 6 through the injection connector 3 and injection main pipe 21. Liquid nitrogen spraying is used to cool the LNG storage tank 6, avoiding rapid temperature changes during LNG refueling and improving refueling safety. During the pre-cooling process, the nitrogen gas formed by the vaporization of liquid nitrogen returns to the nitrogen generator 7 through the return gas main pipe 23, facilitating its reuse for nitrogen production. The nitrogen generator 7 and nitrogen liquefaction unit 8 can start operating before the pre-cooling process to ensure sufficient liquid nitrogen produced by the nitrogen liquefaction unit 8 to meet the pre-cooling requirements.

[0059] like Figure 1 As shown, the LNG recovery tank 9, the receiving main pipe 21, the LNG storage tank 6, and the return gas main pipe 23 form a gas-driving route. After pre-cooling, gas driving is performed. The BOG recovered in the LNG recovery tank 9 enters the LNG storage tank 6 through the receiving main pipe 21, venting the residual nitrogen in the LNG storage tank 6. The vented nitrogen and the BOG used for gas driving are both returned to the nitrogen generator 7 through the return gas main pipe, facilitating their reuse for nitrogen production. The BOG in the LNG recovery tank 9 comes from the vaporized BOG in the LNG storage tank 6 during the previous refueling and the residual LNG in the receiving main pipe 21 and the receiving branch pipe 22 after refueling.

[0060] like Figure 1As shown, the refueling pipeline system 1, the receiving main pipe 21, and the LNG storage tank 6 form the refueling route. When the LNG carrier docks, the gas purging is completed, and the refueling connector 13 and the receiving connector 3 are directly connected for refueling. LNG from the refueling station is refueled into the LNG storage tank 6 through the refueling pipeline system 1 and the receiving main pipe 21. Simultaneously, several LNG storage tanks 6 are refueled through the receiving main pipe 21 and several receiving branch pipes 22, greatly improving refueling efficiency. During the refueling process, the BOG generated by the vaporization in the LNG storage tank 6 is recovered into the LNG recovery tank 9 through the return gas main pipe 23. After refueling, the residual LNG in the receiving main pipe 21 and receiving branch pipes 22 is also recovered into the LNG recovery tank 9 for use in the next gas purging, realizing the recovery and reuse of BOG generated during refueling, effectively reducing costs and avoiding energy waste.

[0061] The basic structure and working principle of the nitrogen generator 7 and the nitrogen liquefaction unit 8 are the same as those in the prior art. Under the premise of meeting the requirements for preparing nitrogen gas and liquid nitrogen, existing equipment with smaller size and simpler structure can be used. The basic structure and working principle of the LNG storage tank 6 are also the same as those in the prior art. Therefore, in this embodiment, the specific structure and working principle of the nitrogen generator 7, the nitrogen liquefaction unit 8 and the LNG storage tank 6 will not be described in detail, and only a simple illustration is shown in the figure.

[0062] like Figure 1 and Figure 2 As shown, in this embodiment, the LNG recovery tank 9 is equipped with a horizontally arranged partition plate 91, which divides the LNG recovery tank 9 into an LNG liquid chamber 92 and a BOG gas chamber 93. The LNG liquid chamber 92 is located above the BOG gas chamber 93. The end of the receiving main pipe 21 away from the receiving connector 3 is connected to the LNG liquid chamber 92, and the return gas main pipe 23 and the receiving connector 3 are connected to the BOG gas chamber 93. During the filling process, the BOG gas generated by the vaporization in the LNG storage tank 6 is recovered into the BOG gas chamber 93 through the return gas main pipe 23. After filling is completed, the remaining LNG in the receiving main pipe 21 and the receiving branch pipe 22 is recovered from the end of the receiving main pipe 21 away from the receiving connector 3 into the LNG liquid chamber 92 for storage in the form of LNG. This avoids the LNG recovery tank 9 being filled with BOG, which could easily lead to excessive pressure and safety accidents. The LNG recovery tank 9 is equipped with an LNG cold insulation cover 921 corresponding to the LNG liquid chamber 92 and a protective cover 931 corresponding to the BOG gas chamber 93. The upper and lower end faces of the partition plate 91 are equipped with a cold insulation layer 911. The LNG cold insulation cover 921 and the cold insulation layer 911 are used to reduce the vaporization of LNG in the LNG liquid chamber 92 into BOG. ​​The protective cover 931 is used to prevent the outer wall of the LNG recovery tank 9 from being too cold and affecting safety.

[0063] In addition, such as Figure 2As shown, the BOG gas chamber 93 is connected to a BOG pressure gauge 94 and a BOG pressure reducing pipe 95, and a BOG pressure reducing valve 951 is installed on the BOG pressure reducing pipe 95. A gas supply pipe 96 connecting the LNG liquid chamber 92 and the BOG gas chamber 93 is installed on the partition plate 91, and a speed regulating valve 961 is installed on the gas supply pipe 96. The BOG pressure gauge 94 is communicatively connected to the BOG pressure reducing valve 951 and the speed regulating valve 961. The BOG pressure gauge 94 monitors the pressure inside the BOG gas chamber 93 in real time. When the monitored pressure is too high, the BOG pressure reducing valve 951 is opened via communication control to release some BOG from the BOG pressure reducing pipe 95, preventing excessive pressure inside the BOG gas chamber 93 from affecting safety. When the BOG pressure gauge 94 detects that the pressure in the BOG gas chamber 93 is too low, it indicates that the BOG reserve is insufficient. The communication control deceleration valve opens the gas supply pipe 96, and the LNG in the LNG liquid chamber 92 enters the BOG gas chamber 93 through the gas supply pipe 96 and is vaporized into BOG to supplement the BOG for driving gas use, ensuring the continuous operation of the driving gas and the driving gas effect.

[0064] like Figure 3 As shown, in this embodiment, the filling connector 13 includes a filling ring 15 and a filling seat 14 that are interconnected. The filling rigid tube 12 is rotatably connected to the end of the filling seat 14 away from the filling ring 15. The filling ring 15 and the filling rigid tube 12 are coaxially arranged. A filling valve core 16 that slides along its axial direction is provided in the filling ring 15. A filling spring 17 that is arranged along the axial direction of the filling ring 15 and abuts against the filling valve core 16 is installed in the filling seat 14. Under normal conditions, the filling valve core 16 blocks the filling ring 15 under the action of the filling spring 17.

[0065] like Figure 4 As shown, the injection connector 3 includes an injection ring 33 and an injection seat 31 that are interconnected. The end of the injection ring 33 away from the injection seat 31 is inserted into and connected to the injection ring 15, and the outer diameter of the end of the injection ring 15 inserted into the injection ring 33 is equal to the inner diameter of the injection ring 33 (e.g., ...). Figure 5 (As shown). The end of the receiving seat 31 furthest from the receiving ring 33 is connected to the receiving main pipe 21, and the other sides of the receiving seat 31 are respectively provided with connections to the storage tank 71, the nitrogen liquefaction unit 8, and the LNG recovery tank 9 (marked in). Figure 1 The main injection pipe 21 is connected to branch pipes 32, and each branch pipe 32 is equipped with a control valve 321 near the injection seat 31 to facilitate switching between inerting drying, pre-cooling, and gas purging working states. An injection valve core 34 is provided in the injection ring 33 and slides along its axis. An injection spring 35 is provided in the injection seat 31 and is arranged along the axis of the injection ring 33 and abuts against the injection valve core 34. Under normal conditions, the injection valve core 34 blocks the injection ring 33 under the action of the injection spring 35.

[0066] like Figure 3 and Figure 4As shown, a plurality of injection receiving rods 18 parallel to its axis are arranged circumferentially on the end face of the injection ring 15 away from the injection seat 14. A plurality of injection receiving holes 341 that mate with the injection receiving rods 18 are provided on the end face of the injection valve core 34 away from the injection spring 35. An elastic protruding ring 181 is provided on the outer wall of the end of the injection receiving rod 18 away from the injection ring 15, and a limiting concave ring 342 that mates with the elastic protruding ring 181 is provided on the inner wall of the injection receiving hole 341. An injection receiving rod 36 is provided inside the injection ring 33 along its axial direction and located on the side of the injection valve core 34 away from the injection spring 35, and the injection receiving rod 36 is located on the axis of the injection ring 33.

[0067] like Figure 5 As described above, when filling the LNG into the filling connector 13 and the receiving connector 3, the filling ring 15 is inserted into the receiving ring 33, and the receiving rod 18 is inserted into the receiving hole 341. Under the cooperation of the elastic convex ring 181 and the limiting concave ring 342, the receiving rod 18 and the receiving valve core 34 are connected. Under the pushing action of the receiving rod 18, the receiving spring 35 is compressed, and the receiving valve core 34 slides open the receiving ring 33. At the same time, under the pushing action of the filling rod 36, the filling spring 17 is compressed, and the filling valve core 16 slides open the filling ring 15. This achieves the connection and communication between the filling ring 15 and the receiving ring 33, which facilitates the filling of LNG.

[0068] like Figure 5 During the filling process, if a pulling impact occurs between the filling pipe system 1 and the receiving pipe system 2 due to the natural environment, the positioning and rotating connection between the filling rigid pipe 12 and the filling connector 13 can buffer part of the impact. In addition, when the filling ring 15 and the receiving ring 33 are pulled, the filling ring 15 slides in the receiving ring 33 and has a tendency to be pulled out. The filling rod 36 pulls the receiving valve core 34 to move. With the push of the receiving spring 35, the receiving valve core 34 moves to reduce or block the flow port of the receiving ring 33. At the same time, as the filling ring 15 moves away from the receiving ring 33, the filling valve core 16 and the filling rod 36 move away from each other. Under the push of the filling spring 17, the filling valve core 16 moves to reduce or block the flow port of the filling ring 15. In this way, when the filling ring 15 and the receiving ring 33 are pulled and moved by external influences, the connection can be effectively adjusted or even closed, thereby avoiding leakage during the filling process and effectively improving the safety of filling.

[0069] like Figure 3 and Figure 4As shown, to further improve the stability of the connection between the filling ring 15 and the receiving ring 33, a plurality of magnetic beads 19 are arranged in a circumferential array on the outer peripheral wall of the filling ring 15 away from the filling seat 14. The magnetic beads 19 are positioned and rolled on the outer wall of the filling ring 15. A plurality of rolling grooves 37 that cooperate with the magnetic beads 19 are arranged in a circumferential array on the inner wall of the receiving ring 33. The rolling grooves 37 are parallel to the axis of the receiving ring 33, and magnetic strips 38 that cooperate with the magnetic beads 19 to attract are embedded in the rolling grooves 37. Additionally, an elastic support 39 is provided inside the injection ring 33 between the injection rod 36 and the injection valve core 34. The elastic support 39 includes a plurality of elastic ribs 391 arranged in a circumferential array around the axis of the injection ring 33. The plurality of elastic ribs 391 are inclined and their ends away from the injection rod 36 are fixed to the inner wall of the injection ring 33. The ends of the plurality of elastic ribs 391 close to the injection rod 36 converge and connect to the end of the injection rod 36 and the end close to it. The plurality of elastic ribs 391 are spaced apart from the injection rod 18.

[0070] like Figure 5 As shown, the quick positioning and insertion of the filling ring 15 and the receiving ring 33 are achieved through the cooperation of the magnetic bead 19 and the rolling groove 37. When the receiving ring 33 and the filling ring 15 are connected, several elastic ribs 391 in the elastic support 39 enter the filling ring 15 together with the filling rod 36, and the elastic ribs 391 abut against the inner wall of the filling ring 15 at the end. Under the elastic support of several elastic ribs 391, the magnetic strip 38 and the magnetic bead 19 are attracted and fixed at the same time. Together with the connection and fixing effect of the elastic protruding ring 181 on the receiving rod 18 and the limiting concave ring 342 in the receiving hole 341, the insertion and fixing effect of the filling ring 15 and the receiving ring 33 is improved, and the reaction force of the LNG flowing out of the filling ring 15 during the filling process is prevented from causing the filling ring 15 and the receiving ring 33 to separate, thus ensuring the stability and safety of the filling.

[0071] like Figure 3 and Figure 5 As shown, to prevent wear of the magnetic beads 19 during prolonged operation from affecting the fixing and sealing effect, several relief grooves 151 corresponding to the magnetic beads 19 are arranged in a circular array on the outer wall of the filling ring 15. Within each relief groove 151, a ball-bearing seat 191 is provided that slides radially along the filling ring 15. The magnetic beads 19 are positioned and rolled on the corresponding ball-bearing seats 191. A clamping spring 192, arranged radially along the filling ring 15, connects the side of the ball-bearing seat 191 away from the magnetic beads 19 and the bottom wall of the relief groove 151. Under the action of the clamping spring 192, the magnetic beads 19 are ensured to always abut against the rolling groove 37 and be attracted and fixed to the magnetic strip 38, preventing wear of the magnetic beads 19 after prolonged use from affecting their fixing and sealing function, ensuring the stability and safety of the filling process. Furthermore, the positioning and rolling of the magnetic beads 19 themselves reduces wear.

[0072] like Figure 4 and Figure 5As shown, to ensure the stability of the refueling connector 13 during installation, an installation assembly 4 is provided on the hull to cooperate with the refueling connector 13 and the receiving connector 3. The installation assembly 4 includes a mounting seat 41 provided on the hull, and a receiving seat 31 is detachably and fixedly installed on the mounting seat 41. During refueling, the refueling seat 14 is slidably and limitedly installed on the mounting seat 41 along the length direction of the receiving main pipe 21. Specifically, a limiting groove 42 is provided on the mounting seat 41 along the length direction of the receiving main pipe 21, and a ball bearing 141 that cooperates with the limiting groove 42 is rotatably mounted on the refueling seat 14. The ball bearing 141 is rotatably installed in the limiting groove 42. A vertically positioned limiting plate 43, which cooperates with the ball 141, is provided at the end of the limiting groove 42 away from the receiving connector 3. The lower end of the limiting plate 43 is eccentrically mounted on the mounting base 41, and its rotation axis is set along the width direction of the limiting groove 42. During normal filling, the limiting plate 43 is in a vertically upward state to prevent the ball 141 from rolling out of the limiting groove 42. During the filling process, when the filling pipeline 1 is pulled between the natural environment and the receiving connector 3, the ball 141 rolls in the limiting groove 42, and the filling ring 15 and the receiving ring 33 slide and adjust first.

[0073] like Figure 4 and Figure 5 As shown, to ensure rapid disconnection of the filling connector 13 and the receiving connector 3 when immediate interruption of filling is required in harsh environments, an unlocking rod 44 is slidably installed in the limiting groove 42, located along its length and on the side of the ball 141 away from the limiting plate 43. A transmission assembly 5 connects the limiting plate 43 and the unlocking rod 44. The transmission assembly 5 includes a deflection motor 51 connected to one end of the rotation shaft of the limiting plate 43. An unlocking gear 52 coaxial with the output shaft of the deflection motor 51 is installed on the output shaft of the deflection motor 51. An unlocking rack 53 along the length of the unlocking rod 44 and meshing with the unlocking gear 52 is provided on the side wall of the unlocking rod 44. A sway sensor 45 is provided on the mounting base 41 and is communicatively connected to the deflection motor 51.

[0074] like Figure 4 and Figure 5As shown, when the sway sensor 45 detects severe hull swaying caused by the natural environment, necessitating an interruption of refueling, the sway sensor 45 communicates with and controls the deflection motor 51 to operate. The deflection motor 51 controls the limit plate 43 to rotate to a vertically downward position, releasing the limit plate 43 from its limiting effect on the ball 141. Simultaneously, the deflection motor 51 drives the unlocking gear 52 to rotate synchronously. Under the meshing action of the unlocking gear 52 and the unlocking rack 53, the unlocking rack 53 drives the unlocking rod 44 to slide along the limit groove 42, pushing the ball 141 out of the limit groove 42. This causes the refueling connector 13 to move as a whole, pulling the refueling ring 15 out of the receiving ring 33, releasing the insertion between the refueling connector 13 and the receiving connector 3. Furthermore, the refueling valve core 16 and the receiving valve core 34 automatically close the refueling ring 15 and the receiving ring 33 under the action of the refueling spring 17 and the receiving spring 35, thus interrupting refueling and preventing leakage and safety accidents. The meshing diagram of the unlocking gear 52 and the unlocking rack 53 is only a simple illustration. As long as the deflection motor 51 drives the limit plate 43 to rotate 180°, the unlocking rod 44 will push the ball 141 out of the limit groove 42.

[0075] Working principle and usage of this invention:

[0076] During the LNG carrier's journey before docking, the LNG storage tank 6 is sequentially dried, inertized, pre-cooled, and purged. When the LNG carrier docks, the receiving connector 3 and the filling connector 13 are directly connected, and LNG is simultaneously filled into several LNG storage tanks 6 through the filling pipeline system 1 and the receiving main pipe 21.

[0077] Drying and inerting: The nitrogen generated by the nitrogen generator 7 enters the LNG storage tank 6 through the storage tank 71, the injection connector 3, and the injection main pipe 21 to inertify the LNG storage tank 6. The nitrogen used for drying and inerting and the remaining gases driven out are returned to the nitrogen generator 7 for reuse through the return gas main pipe 23.

[0078] Pre-cooling: The nitrogen generated by the nitrogen generator 7 enters the nitrogen liquefaction unit 8 through the storage tank 71 to form liquid nitrogen. The liquid nitrogen enters the LNG storage tank 6 through the injection connector 3 and the injection main pipe 21. The LNG storage tank 6 is cooled by liquid nitrogen spraying. During the pre-cooling process, the nitrogen formed by the vaporization of liquid nitrogen returns to the nitrogen generator 7 through the return gas main pipe 23 for reuse.

[0079] Expel Qi: The BOG recovered in the LNG recovery tank 9 enters the LNG storage tank 6 through the injection pipe 21, and the residual nitrogen in the LNG storage tank 6 is discharged. The discharged nitrogen and the BOG used for purging are returned to the nitrogen generator 7 through the return pipe for reuse.

[0080] Note:After the LNG carrier docks, the refueling connector 13 is installed onto the mounting base 41, and the refueling head and the receiving connector 3 are quickly connected. The receiving rod 18 and the refueling rod 36 push the corresponding receiving valve core 34 and refueling valve core 16 to slide open the receiving ring 33 and the refueling ring 15. LNG from the refueling station is simultaneously refueled into several LNG storage tanks 6 through the refueling pipeline system 1, the receiving main pipe 21, and several receiving branch pipes 22. During the refueling process, the BOG generated by the vaporization in the LNG storage tanks 6 is recovered into the LNG recovery tank 9 through the return gas main pipe 23. After refueling is completed, the residual LNG in the receiving main pipe 21 and the receiving branch pipes 22 is also recovered into the LNG recovery tank 9 for use in the next gas purging cycle.

[0081] During the filling process, when the filling pipe system 1 and the receiving pipe system 2 are subjected to pulling and impact due to the natural environment, the positioning and rotating connection between the filling rigid pipe 12 and the filling connector 13 can buffer part of the impact. In addition, the filling ring 15 slides in the receiving ring 33, the filling rod 36 pulls the receiving valve core 34 to move, and the receiving spring 35 pushes the receiving valve core 34 to move to reduce or block the flow port of the receiving ring 33. At the same time, the filling valve core 16 and the filling rod 36 move away from each other, and the filling spring 17 pushes the filling valve core 16 to move to reduce or block the flow port of the filling ring 15 to avoid leakage during the filling process.

[0082] When the sway sensor 45 detects that the hull is swaying severely due to the natural environment and refueling needs to be interrupted, the control deflection motor 51 rotates the limit plate 43 to a vertically downward position. At the same time, the deflection motor 51 drives the unlocking gear 52 to rotate synchronously. The engagement of the unlocking gear 52 and the unlocking rack 53 drives the unlocking rod 44 to slide along the limit groove 42, pushing the ball 141 out of the limit groove 42 and pulling the refueling ring 15 out of the receiving ring 33. Under the action of the refueling spring 17 and the receiving spring 35, the refueling valve core 16 and the receiving valve core 34 automatically close the refueling ring 15 and the receiving ring 33, thereby interrupting refueling.

[0083] The foregoing description illustrates and describes preferred embodiments of the present invention. As previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A high-efficiency refueling system for LNG carriers, characterized in that: It includes several LNG storage tanks (6) installed on the hull, a receiving pipeline system (2) connected to the LNG storage tanks (6), a nitrogen generator (7) connected to the receiving pipeline system (2), a nitrogen liquefaction unit (8), an LNG recovery tank (9), and a refueling pipeline system (1) installed at the refueling station and connected to the receiving pipeline system (2); the several LNG storage tanks (6) are arranged in an array along the length of the hull, and their axes are arranged horizontally along the width of the hull; The injection piping system (2) includes an injection main pipe (21) and a return gas main pipe (23) arranged along the length of the hull and located at both ends of the LNG storage tank (6). Each LNG storage tank (6) is connected to the injection main pipe (21) through an injection branch pipe (22) and to the return gas main pipe (23) through a return gas branch pipe (24). Each injection branch pipe (22) and return gas branch pipe (24) is equipped with an automatic valve (25) and a manual valve (26) to control their opening and closing. The nitrogen generator (7) is connected to the nitrogen liquefaction unit (8). The end of the injection main pipe (21) is provided with an injection connector (3). The injection connector (3) is connected to the nitrogen generator (7), the nitrogen liquefaction unit (8), and the LNG recovery tank (9) respectively. The end of the injection main pipe (21) away from the injection connector (3) is also connected to the LNG recovery tank (9) and is provided with a recovery valve (211). One end of the return gas main pipe (23) is connected to the nitrogen generator (7) and the LNG recovery tank (9). The filling piping system (1) includes a filling hose (11), a filling rigid pipe (12), and a filling connector (13). One end of the filling hose (11) is connected to the filling station, and the other end is connected to the filling rigid pipe (12). The inner diameter of the filling rigid pipe (12) is larger than the inner diameter of the filling hose (11). The end of the filling rigid pipe (12) away from the filling hose (11) is rotatably connected to the filling connector (13). The filling connector (13) and the receiving connector (3) are detachably connected. The nitrogen generator (7), the injection main pipe (21), the LNG storage tank (6), and the return gas main pipe (23) form a drying and inerting route, and the nitrogen gas used for drying and inerting returns to the nitrogen generator (7) through the return gas main pipe (23). The nitrogen generator (7), nitrogen liquefaction unit (8), injection main pipe (21), LNG storage tank (6), and return gas main pipe (23) form a pre-cooling route, and the nitrogen discharged from the pre-cooling returns to the nitrogen generator (7) through the return gas main pipe (23). The LNG recovery tank (9), the injection main pipe (21), the LNG storage tank (6), and the return gas main pipe (23) form a gas driving route, and the BOG used for gas driving and the nitrogen driven out return to the nitrogen generator (7) through the return gas main pipe (23). The refueling pipeline (1), the main refueling pipe (21), and the LNG storage tank (6) form a refueling route. The BOG generated by the vaporization in the LNG storage tank (6) is recovered into the LNG recovery tank (9) through the return gas main pipe (23). After the refueling is completed, the remaining LNG in the main refueling pipe (21) and the refueling branch pipe (22) is recovered into the LNG recovery tank (9).

2. The high-efficiency refueling system for LNG carriers according to claim 1, characterized in that: The filling connector (13) includes a filling seat (14) connected to the filling hard pipe (12) and a filling ring (15) connected to the end of the filling seat (14) away from the filling hard pipe (12). The receiving connector (3) includes a receiving ring (33) connected to the filling ring (15) and a receiving seat (31) connected to the end of the receiving ring (33) away from the filling ring (15). The receiving seat (31) is connected to branch pipes (32) that are respectively connected to the nitrogen generator (7), the nitrogen liquefaction unit (8) and the LNG recovery tank (9). Each branch pipe (32) is provided with a sub-control valve (321) near the receiving seat (31). The filling ring (15) is provided with a filling valve core (16) that slides along its axis, the receiving ring (33) is provided with a receiving valve core (34) that slides along its axis, the filling seat (14) is provided with a filling spring (17) that abuts against the filling valve core (16), and the receiving seat (31) is provided with a receiving spring (35) that abuts against the receiving valve core (34). Under normal conditions, under the action of the filling spring (17) and the receiving spring (35), the filling valve core (16) and the receiving valve core (34) respectively block the filling ring (15) and the receiving ring (33). The outer diameter of the filling ring (15) inserted into the receiving ring (33) is equal to the inner diameter of the receiving ring (33) and its connection point. The end face of the filling ring (15) away from the filling seat (14) is circumferentially arranged with a plurality of receiving rods (18) parallel to its axis. The end face of the receiving valve core (34) away from the receiving spring (35) is provided with a plurality of receiving holes (341) that cooperate with the receiving rods (18). The outer wall of the end of the receiving rod (18) away from the filling ring (15) is provided with an elastic protruding ring (181). The inner wall of the receiving hole (341) is provided with a limiting concave ring (342) that cooperates with the elastic protruding ring (181). The receiving ring (33) is provided with a filling rod (36) arranged along its axis and located on the side of the receiving valve core (34) away from the receiving spring (35). The filling rod (36) is located on the axis of the receiving ring (33). When the filling connector (13) and the receiving connector (3) are connected, the filling ring (15) is inserted into the receiving ring (33), and the receiving rod (18) is inserted into the receiving socket (341) to push the receiving valve core (34) to open the receiving ring (33). The filling rod (36) abuts against the filling valve core (16) and pushes the filling valve core (16) to open the filling ring (15).

3. The high-efficiency refueling system for LNG carriers according to claim 2, characterized in that: The outer circumferential wall of the filling ring (15) away from the filling seat (14) is provided with a plurality of magnetic beads (19), and the plurality of magnetic beads (19) are positioned and rolled on the outer wall of the filling ring (15); the inner circumferential wall of the receiving ring (33) is provided with a plurality of rolling grooves (37) that cooperate with the magnetic beads (19), the rolling grooves (37) are parallel to the axis of the receiving ring (33), and the rolling grooves (37) are embedded with magnetic strips (38) that cooperate with the magnetic beads (19) to attract them.

4. The high-efficiency refueling system for LNG carriers according to claim 3, characterized in that: The outer wall of the filling ring (15) is provided with a plurality of relief grooves (151) corresponding to the magnetic beads (19). The relief grooves (151) are provided with ball bearing seats (191) that slide radially along the filling ring (15). The magnetic beads (19) are positioned and rolled on the corresponding ball bearing seats (191). A retaining spring (192) is connected between the side of the ball bearing seat (191) away from the magnetic beads (19) and the bottom wall of the relief groove (151). The retaining spring (192) is arranged radially along the filling ring (15).

5. The high-efficiency refueling system for LNG carriers according to claim 2, characterized in that: The receiving ring (33) is provided with an elastic support (39) located between the filling rod (36) and the receiving valve core (34). The elastic support (39) includes a plurality of elastic ribs (391) arranged in a circular array around the axis of the receiving ring (33). The plurality of elastic ribs (391) are inclined and their ends away from the filling rod (36) are fixed to the inner wall of the receiving ring (33). The ends of the plurality of elastic ribs (391) close to the filling rod (36) converge and connect to the end of the filling rod (36) and the end close to it. The plurality of elastic ribs (391) are spaced apart from the receiving rod (18).

6. The high-efficiency refueling system for LNG carriers according to claim 2, characterized in that: The hull is provided with an installation assembly (4) that mates with the filling connector (13) and the receiving connector (3). The installation assembly (4) includes a mounting seat (41) on the hull. The receiving seat (31) is detachably and fixedly mounted on the mounting seat (41). The filling seat (14) is slidably mounted on the mounting seat (41) along the length of the receiving pipe (21). The mounting seat (41) is provided with a limiting groove (42) along the length of the receiving pipe (21). A ball bearing (141) that mates with the limiting groove (42) is rotatably mounted on the filling seat (14). The ball bearing (141) is rotatably mounted in the limiting groove (42). A vertically arranged limiting plate (43) is provided at one end of the slide groove (42) away from the injection connector (3) and cooperates with the ball (141). The lower end of the limiting plate (43) is eccentrically mounted on the mounting base (41), and its rotation axis is set along the width direction of the limiting slide groove (42). An unlocking rod (44) is slidably installed in the limiting slide groove (42) along its length direction and located on the side of the ball (141) away from the limiting plate (43). A transmission assembly (5) is connected between the limiting plate (43) and the unlocking rod (44). A shaking sensor (45) is provided on the mounting base (41), and the shaking sensor (45) is communicatively connected to the transmission assembly (5).

7. The high-efficiency refueling system for LNG carriers according to claim 6, characterized in that: The transmission assembly (5) includes a deflection motor (51) connected to one end of the rotation shaft of the limiting plate (43). The output shaft of the deflection motor (51) is equipped with an unlocking gear (52) coaxial with it. The side wall of the unlocking rod (44) is provided with an unlocking rack (53) that is arranged along its length and meshes with the unlocking gear (52). The shaking sensor (45) is connected to the deflection motor (51) for communication control. When the deflection motor (51) drives the limiting plate (43) to rotate from vertically upward to vertically downward, the unlocking rod (44) is driven to push the ball (141) out of the limiting groove (42) to release the connection between the filling connector (13) and the receiving connector (3) through the meshing of the unlocking gear (52) and the unlocking rack (53).

8. The high-efficiency refueling system for LNG carriers according to claim 1, characterized in that: A storage tank (71) is provided between the nitrogen generator (7) and the nitrogen liquefaction unit (8). The storage tank (71) is connected to the nitrogen generator (7) and the nitrogen liquefaction unit (8) respectively. A nitrogen pressure gauge (72) and a nitrogen pressure reducing pipe (73) are connected to the storage tank (71). A nitrogen pressure reducing valve (74) is provided on the nitrogen pressure reducing pipe (73). The nitrogen pressure gauge (72) and the nitrogen pressure reducing valve (74) are connected for communication control. A nitrogen cold insulation cover (81) is provided on the outside of the nitrogen liquefaction unit (8). A heat insulation layer (82) is provided on the outside of the nitrogen cold insulation cover (81).

9. The high-efficiency refueling system for LNG carriers according to claim 1, characterized in that: The LNG recovery tank (9) is provided with a partition plate (91) that divides it into an LNG liquid chamber (92) and a BOG gas chamber (93). The LNG liquid chamber (92) is located above the BOG gas chamber (93). The end of the injection pipe (21) away from the injection connector (3) is connected to the LNG liquid chamber (92). The return gas pipe (23) and the injection connector (3) are connected to the BOG gas chamber (93). The LNG recovery tank (9) is provided with an LNG cold insulation cover (921) corresponding to the LNG liquid chamber (92) and a protective cover (931) corresponding to the BOG gas chamber (93). The upper and lower surfaces of the partition plate (91) are provided with a cold insulation layer (911).

10. A high-efficiency refueling system for LNG carriers according to claim 9, characterized in that: The BOG gas chamber (93) is connected to a BOG pressure gauge (94) and a BOG pressure reducing pipe (95), and a BOG pressure reducing valve (951) is provided on the BOG pressure reducing pipe (95); the partition plate (91) is provided with a gas supply pipe (96) connecting the LNG liquid chamber (92) and the BOG gas chamber (93), and a speed regulating valve (961) is provided on the gas supply pipe (96). The BOG pressure gauge (94) is connected to the BOG pressure reducing valve (951) and the speed regulating valve (961) for communication control.

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