LNG (Liquefied Natural Gas) fuel supply system of oversized box ship

Abstract

The invention discloses an LNG (Liquefied Natural Gas) fuel supply system for a super-large box ship, which is applied to the field of engine fuel supply and is characterized in that an air temperature gasifier and a water bath gasifier are arranged in series to realize two-stage gasification treatment on LNG, so that the risk that ungasified LNG damages a downstream pipeline is reduced, meanwhile, environmental heat energy is preferentially utilized, and water bath heating is supplemented only when needed, so that the energy consumption is reduced, and the energy consumption is reduced. The operation energy consumption is obviously reduced; meanwhile, the electric heating pipe is used for assisting gasification in the engine starting stage, and the stable operation stage is switched to cylinder sleeve circulating hot water heating, so that the gasification reliability under different working conditions is guaranteed; in addition, the system further seals a pipeline valve and a flange through a sealing box, environmental moisture contact is reduced, the risks of icing of the outer walls of a connector and the valve, jamming of moving parts and sealing performance reduction are reduced, humidity in the box is reduced in cooperation with a dehumidifier, airflow is guided to flow circularly through a partition plate, and the dehumidification efficiency and the anti-freezing effect are further improved.

Description

Technical Field

[0001] This invention relates to the field of engine fuel supply, and in particular to an LNG fuel supply system for ultra-large container ships. Background Technology

[0002] LNG (liquefied natural gas) fuel, as a clean and efficient energy source, is increasingly widely used in marine propulsion systems. Existing marine LNG fuel supply systems typically include LNG storage tanks, vaporizers, buffer tanks, pressure regulating valve assemblies, and corresponding control and safety devices. Its basic working principle is to use a vaporizer to heat and vaporize cryogenic liquid LNG, and then supply it to the ship's engine after pressure regulation and stabilization.

[0003] The existing patent with publication number CN112412664B discloses a ship and LNG fuel gas supply system. By connecting the exhaust port of the pressure pump to the gas pipe of the liquid storage tank and the inlet of the gas storage tank respectively, the liquid storage tank, the pressure pump and the gas storage tank form a closed space, so that the BOG gas continuously accumulates in the limited space and achieves self-compression by using the pressure between the gases. Thus, the BOG gas obtains the pressure required for combustion without adding external pressure equipment.

[0004] The existing patent with publication number CN102840058B discloses an LNG-fueled marine liquid storage and gas supply system. It sets up a sealed box to contain the LNG storage tank valves and gas supply system valves, and extends the end of the gas supply pipeline inside the box to connect with the engine room. It also configures inlet and outlet pipes and a gas leakage monitoring module to realize the safe arrangement of the gas supply system inside the cabin or on the deck, and in the event of a leak, the natural gas is discharged to a safe area outside the cabin through the exhaust pipe.

[0005] The aforementioned prior art discloses a technical solution that utilizes BOG gas to continuously accumulate and compress within a confined space to meet the combustion gas supply pressure. It also discloses a technical solution that utilizes a sealed box and an exhaust device to provide timely warnings and handle gas leaks. However, the prior art still has shortcomings. When the low-temperature LNG is not fully vaporized, it is easy to freeze and block downstream pipelines, damaging equipment, valves, and flanges, and affecting the stable operation of the equipment. Summary of the Invention

[0006] The core of this invention lies in solving the problem of insufficient LNG vaporization damaging downstream pipelines in the prior art by using an air-temperature vaporizer and a water bath vaporizer connected in series. At the same time, it reduces the probability of valve jamming and flange sealing performance degradation by using a sealed box and a dehumidifier.

[0007] To solve the above problems, the present invention adopts the following technical solution.

[0008] An LNG fuel supply system for a super-large container ship includes a storage tank; the storage tank is connected to an ambient air vaporizer via a drain pipe, the ambient air vaporizer is connected to a water bath vaporizer via an exhaust pipe, and the water bath vaporizer is connected to the fuel inlet of an engine via a pressure regulating pipe. The water bath vaporizer includes a shell, inside which a heat exchange tube assembly is provided. The lower end of the heat exchange tube assembly is connected to the outlet of the exhaust pipe, and the upper end of the heat exchange tube assembly is connected to the inlet of the pressure regulating pipe. Multiple linearly equidistant heat exchange fins are fixedly connected to the outer wall of the heat exchange tube assembly. An electric heating tube is fixedly connected to the inner wall of the shell. The shell is filled with circulating water, and the electric heating tube is used to heat the circulating water inside the shell. The right end of the outer casing is fixedly connected to a first water inlet connector, which is fixedly connected to a first water inlet branch pipe. The right end of the first water inlet branch pipe is fixedly connected to a main water inlet pipe, and the right end of the main water inlet pipe is fixedly connected to the outlet of the cylinder liner. The left end of the outer casing is fixedly connected to a first water outlet connector, which is fixedly connected to a first water outlet branch pipe. The left end of the first water outlet branch pipe is fixedly connected to a return water main pipe, and the right end of the return water main pipe is fixedly connected to the water inlet of the cylinder liner. A hot water circulation pump is fixedly connected to the return water main pipe, which causes hot water to circulate between the cylinder liner and the water bath vaporizer.

[0009] Furthermore, the first water inlet connector and the first water outlet connector are symmetrically arranged on both sides of the shell. A pair of symmetrically arranged dispersion plates are provided on the outer side of the heat exchange fins. Both dispersion plates are fixedly connected to the inner wall of the shell. The dispersion plates are arranged opposite to the first water inlet connector. Multiple dispersion grooves are opened on the dispersion plates at equal intervals. The gaps between the dispersion grooves and the adjacent heat exchange fins are arranged opposite to each other.

[0010] Furthermore, the outer shell is a hollow rectangular box, the dispersion plate is a rectangular plate, and a pair of dispersion plates divide the inner cavity of the outer shell into three cavities. The adjacent cavities are connected by dispersion grooves, which are strip-shaped through grooves.

[0011] Furthermore, a primary pressure reducing valve and a secondary pressure reducing valve are fixedly connected to the pressure regulating pipeline. A heating cylinder is fixedly sleeved on the pipe section between the primary and secondary pressure reducing valves. The water inlet end of the heating cylinder is fixedly connected to a second water inlet branch pipe. The end of the second water inlet branch pipe away from the heating cylinder is connected to the main water inlet pipe. The water outlet end of the heating cylinder is fixedly connected to a second water outlet branch pipe. The end of the second water outlet branch pipe away from the heating cylinder is fixedly connected to the main return water pipe.

[0012] Furthermore, the heating cylinder includes a cylinder body, which is fixedly sleeved on the pressure regulating pipeline and surrounds it to form an annular cavity. A spiral guide plate is fixedly connected to the inner wall of the annular cavity. A second water inlet connector is fixedly connected to the upper end of the cylinder body, and the second water inlet connector is fixedly connected to the second water inlet branch pipe. A second water outlet connector is fixedly connected to the lower end of the cylinder body, and the second water outlet connector is fixedly connected to the second water outlet branch pipe.

[0013] Furthermore, a first temperature sensor is fixedly connected to the portion of the exhaust pipe near the outlet end of the air-temperature vaporizer. The first temperature sensor is used to detect the temperature of the natural gas after it has been vaporized by the air-temperature vaporizer. A second temperature sensor is fixedly connected to the portion of the pressure regulating pipe near the outlet end of the water bath vaporizer. The second temperature sensor is used to detect the temperature of the natural gas before it enters the first-stage pressure reducing valve. A third temperature sensor is fixedly connected to the portion of the pressure regulating pipe located at the outlet end of the second-stage pressure reducing valve. The third temperature sensor is used to detect the temperature of the natural gas entering the engine.

[0014] Furthermore, the gas supply system also includes a sealed box, with the drain pipe fixedly passing through the sealed box and the valves and flanges installed on it all located inside the sealed box. The air-temperature vaporizer is fixed to the outer wall of the sealed box by a mounting bracket. The valves and flanges installed on the exhaust pipe are all installed inside the sealed box. The water bath vaporizer is fixedly connected to the inner wall of the sealed box by a mounting bracket. The valves and flanges on the pressure regulating pipe are all installed inside the sealed box. A dehumidifier and a humidity sensor are fixedly connected to the bottom wall of the sealed box.

[0015] Furthermore, a sealing door is hinged to the front end of the sealed box, and a pair of partitions are fixedly connected to the inner wall of the sealed box. An upper exhaust groove is opened on the upper part of the partition, and a lower exhaust groove is opened at the lower end. A mesh plate is fixedly connected between the pair of partitions, and a heating element is provided below the mesh plate. The inlet end of the heating element is connected to the main water inlet pipe through a third water inlet branch pipe, and the outlet end of the heating element is connected to the main return water pipe through a third water outlet branch pipe.

[0016] Compared with the prior art, the advantages of this invention are: (1) This invention achieves two-stage vaporization of LNG by setting an ambient temperature vaporizer and a water bath vaporizer in series. This design not only makes LNG vaporization more thorough and effectively reduces the risk of unvaporized LNG damaging downstream pipelines and improves system safety, but also makes full use of ambient heat energy for priority vaporization, supplemented only by water bath heating when needed, which significantly reduces operating energy consumption. During the engine start-up phase, the system uses electric heating tubes to assist vaporization, and during the stable operation phase, it switches to cylinder liner circulating hot water for heating, thereby ensuring the vaporization reliability of the gas supply system under different operating conditions. In addition, by using the cylinder liner circulating hot water to preheat the pressure reducing pipeline through the heating cylinder, the probability of ice blockage of the pressure reducing valve due to throttling expansion can be effectively reduced.

[0017] (2) The present invention uses a sealed box to seal the valves and flanges on the pipeline, reducing the probability of environmental moisture coming into contact with the valves and flanges, thereby reducing the probability of ice forming at the equipment interface and on the outer wall of the valves and flanges, and further reducing the probability of the moving parts of the valves getting stuck, while also reducing the probability of the sealing performance at the equipment interface and flange connection deteriorating; in addition, the dehumidifier reduces the humidity inside the sealed box, further reducing the probability of ice forming on the valves and flanges, and with the help of the partition, the airflow inside the sealed box circulates, improving the dehumidification speed and effect. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the pipeline connection of the present invention; Figure 2 This is a three-dimensional structural diagram of the water bath vaporizer in this invention; Figure 3 This is a schematic diagram of the internal structure of the water bath vaporizer in this invention; Figure 4 This is a schematic diagram of the exploded structure of the water bath vaporizer in this invention; Figure 5 This is a schematic diagram of the flow of circulating hot water in the water bath vaporizer in this invention; Figure 6 This is a three-dimensional structural diagram of the heating cylinder in this invention; Figure 7 This is a schematic diagram of the internal structure of the heating cylinder in this invention; Figure 8 This is a three-dimensional structural diagram of the sealed box in this invention; Figure 9 This is a schematic diagram of the internal structure of the sealed box in this invention; Figure 10 This is a schematic diagram of airflow within the sealed box in this invention.

[0019] Explanation of the labels in the diagram: 1. Storage tank; 2. Drainage pipeline; 3. Ambient air vaporizer; 4. Exhaust pipeline; 5. Water bath vaporizer; 501. Shell; 502. Heat exchanger tube assembly; 503. Heat exchanger fins; 504. Dispersion plate; 505. Dispersion tank; 506. First water inlet connector; 507. First water outlet connector; 508. Electric heating tube; 6. Pressure regulating pipeline; 7. Engine; 8. Cylinder liner; 9. Main water inlet pipe; 10. First water inlet branch pipe; 11. First water outlet branch pipe; 12. Main return water pipe; 13. Hot water circulation pump; 14. Second water inlet branch pipe; 15. Heating cylinder; 1501 1502. Cylinder body; 1503. Second water inlet connector; 1504. Second water outlet connector; 1505. Spiral guide plate; 16. Second water outlet branch pipe; 17. Third water inlet branch pipe; 18. Heating outlet; 19. Third water outlet branch pipe; 20. Sealed box; 2001. Sealed door; 21. Dehumidifier; 22. Humidity sensor; 23. First-stage pressure reducing valve; 24. Second-stage pressure reducing valve; 25. First temperature sensor; 26. Second temperature sensor; 27. Partition plate; 2701. Upper exhaust duct; 2702. Lower exhaust duct; 28. Mesh plate; 29. ​​Third temperature sensor. Detailed Implementation

[0020] The technical solutions will now be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention.

[0021] First implementation method Please see Figure 1 In one embodiment of the present invention, an LNG fuel supply system for a super-large container ship includes a storage tank 1; the storage tank 1 is connected to an ambient air vaporizer 3 through a drain pipe 2, the ambient air vaporizer 3 is connected to a water bath vaporizer 5 through an exhaust pipe 4, and the water bath vaporizer 5 is connected to the fuel inlet of an engine 7 through a pressure regulating pipe 6. Please see Figure 1 , Figure 3 and Figure 4 The water bath vaporizer 5 includes a shell 501, inside which a heat exchange tube assembly 502 is provided. The lower end of the heat exchange tube assembly 502 is connected to the outlet of the exhaust pipe 4, and the upper end of the heat exchange tube assembly 502 is connected to the inlet of the pressure regulating pipe 6. Multiple linearly equidistant heat exchange fins 503 are fixedly connected to the outer wall of the heat exchange tube assembly 502. An electric heating tube 508 is fixedly connected to the inner wall of the shell 501. The shell 501 is filled with circulating water, and the electric heating tube 508 is used to heat the circulating water inside the shell 501. Please see Figure 1 , Figure 3 and Figure 4The right end of the outer casing 501 is fixedly connected to a first water inlet connector 506, the first water inlet connector 506 is fixedly connected to a first water inlet branch pipe 10, the right end of the first water inlet branch pipe 10 is fixedly connected to a main water inlet pipe 9, the right end of the main water inlet pipe 9 is fixedly connected to the outlet of the cylinder liner 8, the left end of the outer casing 501 is fixedly connected to a first water outlet connector 507, the left end of the first water outlet connector 507 is fixedly connected to a first water outlet branch pipe 11, the left end of the first water outlet branch pipe 11 is fixedly connected to a return water main pipe 12, the right end of the return water main pipe 12 is fixedly connected to the water inlet of the cylinder liner 8, and a hot water circulation pump 13 is fixedly connected to the return water main pipe 12. The hot water circulation pump 13 makes hot water circulate between the cylinder liner 8 and the water bath vaporizer 5.

[0022] Specifically, the LNG in storage tank 1 enters the ambient air vaporizer 3 through the drain pipe 2. After initial vaporization in the ambient air vaporizer 3, the LNG is injected into the water bath vaporizer 5 through the exhaust pipe 4 for secondary vaporization. Then, it is injected into the engine 7 after pressure reduction and stabilization through the pressure regulating pipe 6. During the start-up phase of the engine 7, the circulating water temperature in the cylinder liner 8 has not reached the circulating temperature. Therefore, it is necessary to start the electric heating tube 508 in the water bath vaporizer 5 to heat the water in the water bath vaporizer 5, thereby accelerating the vaporization of LNG and making the vaporization of LNG more thorough, so as to avoid LNG freezing and blocking the downstream pipeline. It should be noted that storage tank 1 is connected to a self-pressurizing drain system. The self-pressurizing drain system refers to a device that vaporizes part of the LNG and guides it back to the gas phase space of the storage tank, and uses the pressure difference to squeeze the LNG in the tank out. This is existing technology and will not be described in detail here.

[0023] Compared to traditional ship gas supply systems, this invention achieves two-stage gasification of LNG through a series connection of an ambient air vaporizer 3 and a water bath vaporizer 5. This results in more thorough LNG vaporization, reduces the probability of unvaporized LNG damaging downstream pipelines, and improves system safety. Furthermore, by connecting the ambient air vaporizer 3 and the water bath vaporizer 5 in series, it can prioritize the use of ambient heat energy for vaporization (energy saving) and supplement heat through water bath heating when needed (ensuring vaporization rate). Compared to a single water bath vaporization method, this solution significantly reduces operating energy consumption while ensuring vaporization effectiveness. During the engine 7 start-up phase, an electric heating tube 508 is used for auxiliary vaporization, while during the engine 7's stable operation phase, circulating hot water within the cylinder liner 8 is used for heating and vaporization, improving the reliability of the gas supply system's vaporization at different operating stages.

[0024] Please see Figure 3 and Figure 4The first water inlet connector 506 and the first water outlet connector 507 are symmetrically arranged on both sides of the outer shell 501. A pair of symmetrically arranged dispersion plates 504 are provided on the outer side of the heat exchange fins 503. Both dispersion plates 504 are fixedly connected to the inner wall of the outer shell 501. The dispersion plates 504 are arranged opposite to the first water inlet connector 506. Multiple equally spaced dispersion grooves 505 are opened on the dispersion plates 504. The gaps between the dispersion grooves 505 and the adjacent heat exchange fins 503 are arranged opposite to each other.

[0025] Specifically, when hot water flows through the water bath vaporizer 5, the water flow is evenly dispersed into multiple streams by the dispersion plate 504. These multiple streams flow evenly through the gaps formed between adjacent heat exchange fins 503, allowing the circulating hot water to fully contact the heat exchange fins 503, improving heat exchange efficiency, and thus optimizing the LNG vaporization effect.

[0026] Please see Figure 1 , Figure 3 , Figure 4 and Figure 5 The outer shell 501 is a hollow rectangular box, the dispersion plate 504 is a rectangular plate, and a pair of dispersion plates 504 divide the inner cavity of the outer shell 501 into three cavities. The adjacent cavities are connected by a dispersion groove 505, which is a strip-shaped through groove.

[0027] Specifically, the strip-shaped through-groove dispersion groove 505 allows the hot water entering the shell 501 to flow evenly across the surface of the heat exchange fins 503. It should be noted that the heat exchange tube assembly 502 includes an inlet pipe, an outlet pipe, and multiple parallel heat exchange branch pipes connecting the two. The heat exchange branch pipes are fixedly inserted through the heat exchange fins 503, and the inlet pipe and outlet pipe are respectively located on the upper and lower sides of the shell 501. The two ends of the multiple parallel heat exchange branch pipes are welded or expanded to the inlet pipe and outlet pipe respectively, forming a tube-side structure similar to that of a shell-and-tube heat exchanger.

[0028] Please see Figure 1 and Figure 6 A primary pressure reducing valve 23 and a secondary pressure reducing valve 24 are fixedly connected to the pressure regulating pipeline 6. A heating cylinder 15 is fixedly sleeved on the pipe section between the primary pressure reducing valve 23 and the secondary pressure reducing valve 24 in the pressure regulating pipeline 6. The water inlet end of the heating cylinder 15 is fixedly connected to a second water inlet branch pipe 14. The end of the second water inlet branch pipe 14 away from the heating cylinder 15 is connected to the main water inlet pipe 9. The water outlet end of the heating cylinder 15 is fixedly connected to a second water outlet branch pipe 16. The end of the second water outlet branch pipe 16 away from the heating cylinder 15 is fixedly connected to the main water return pipe 12.

[0029] Specifically, when gaseous natural gas flows through the two-stage pressure reducing valve of the pressure regulating pipeline 6, throttling expansion is very likely to occur due to the Joule-Thomson effect. Specifically, when high-pressure gas passes through the narrow valve orifice of the pressure reducing valve, the flow area decreases sharply, the gas pressure drops drastically, and the volume expands rapidly. This process requires the absorption of a large amount of heat (isenthalpic expansion). If the initial temperature of the gas is not high enough, or the pressure difference across the valve is too large, the temperature of the gas will drop rapidly below the freezing point of water during the expansion and cooling process. At this time, if there is moisture in the natural gas pipeline system (even after dehydration treatment, it usually still contains trace amounts of saturated water vapor), this free water or water vapor will freeze rapidly in the low-temperature environment, forming ice or hydrates at the valve core, valve seat, or throttling orifice of the pressure reducing valve, thereby causing the valve to malfunction and the flow channel to be blocked, i.e., the so-called "ice blockage" fault. This application reduces the probability of icing by adding a heating cylinder 15 to heat the part of the pressure regulating pipeline 6 located at the two-stage pressure reducing valve, thereby further improving the reliability of the gas supply system.

[0030] Please see Figure 1 , Figure 6 and Figure 7 The heating cylinder 15 includes a cylinder body 1501, which is fixedly sleeved on the pressure regulating pipe 6 and forms an annular cavity with it. A spiral guide plate 1504 is fixedly connected to the inner wall of the annular cavity. A second water inlet connector 1502 is fixedly connected to the upper end of the cylinder body 1501 and is fixedly connected to the second water inlet branch pipe 14. A second water outlet connector 1503 is fixedly connected to the lower end of the cylinder body 1501 and is fixedly connected to the second water outlet branch pipe 16.

[0031] Specifically, the circulating hot water entering the cylinder 1501 is guided by the spiral guide plate 1504, and the flow trajectory of the circulating hot water is spiral, so that the hot water and the pressure regulating pipe 6 can fully exchange heat, thereby improving the heating effect of the pressure regulating pipe 6.

[0032] Please see Figure 1 A first temperature sensor 25 is fixedly connected to the part of the exhaust pipe 4 near the outlet end of the air-temperature vaporizer 3. The first temperature sensor 25 is used to detect the temperature of the natural gas after it has been vaporized by the air-temperature vaporizer 3. A second temperature sensor 26 is fixedly connected to the part of the pressure regulating pipe 6 near the outlet end of the water bath vaporizer 5. The second temperature sensor 26 is used to detect the temperature of the natural gas before it enters the first-stage pressure reducing valve 23. A third temperature sensor 29 is fixedly connected to the part of the pressure regulating pipe 6 located at the outlet end of the second-stage pressure reducing valve 24. The third temperature sensor 29 is used to detect the temperature of the natural gas entering the engine 7.

[0033] Specifically, the first temperature sensor 25 is used to detect the temperature of the natural gas after it has been vaporized by the ambient air vaporizer 3. The temperature is used to determine whether the LNG flowing through the ambient air vaporizer 3 has been fully vaporized. The phase change temperature of LNG (methane) at normal pressure is -162℃, while in high-pressure pipelines (such as at 6MPa), the phase change temperature is about -60℃. Therefore, when the outlet temperature is -20℃, although the gas has been completely vaporized (meaning that it is no longer in a liquid state), if the downstream requires ambient temperature gas, this is still considered as not being reheated. It is usually included in the broad discussion of "incomplete vaporization" because it can lead to ice blockage in subsequent equipment. In order to ensure absolute safety and stable operation, in engineering practice, the outlet temperature is usually required to be higher than the dew point temperature at its working pressure by a certain margin, usually 5℃-10℃, to leave sufficient safety margin. The second temperature sensor 26 is used to detect the temperature of natural gas before it enters the first-stage pressure reducing valve 23. By controlling the power of the electric heating tube 508 and adjusting the hot water circulation flow through the water bath vaporizer 5 and the heating cylinder 15, the initial temperature of the natural gas before entering the two-stage pressure reducing valve can be effectively increased. (When the second temperature sensor 26 detects that the natural gas temperature is lower than the preset threshold (e.g., 5°C), the control system increases the heating power of the electric heating tube 508 and adjusts the speed of the hot water circulation pump 13 to increase the hot water flow through the heating cylinder 15 until the natural gas temperature returns to a safe range.) This reduces the probability of ice blockage. In addition, the third temperature sensor 29 is used to detect the temperature of natural gas entering the engine 7. By controlling the hot water circulation flow of the heating cylinder 15, the natural gas entering the engine 7 is heated to increase the intake temperature, thereby making full use of the engine heat and improving the combustion efficiency of the natural gas.

[0034] Second implementation method Based on the first implementation, please refer to Figure 1 and Figure 8 The gas supply system also includes a sealed box 20. The drain pipe 2 is fixedly inserted through the sealed box 20, and the valves and flanges installed on it are all located inside the sealed box 20. The air-temperature vaporizer 3 is fixed to the outer wall of the sealed box 20 by a mounting bracket. The valves and flanges installed on the exhaust pipe 4 are all installed inside the sealed box 20. The water bath vaporizer 5 is fixedly connected to the inner wall of the sealed box 20 by a mounting bracket. The valves and flanges on the pressure regulating pipe 6 are all installed inside the sealed box 20. A dehumidifier 21 and a humidity sensor 22 are fixedly connected to the bottom wall of the sealed box 20.

[0035] Specifically, by installing all valves and flanges (connecting flanges between pipes, connecting flanges between valves and pipes, and connecting flanges between equipment and pipes) on the pipeline between storage tank 1 and engine 7 inside the sealed box 20, moisture in the outside air cannot enter the sealed box 20. In addition, the dehumidifier 21 removes moisture from the inside of the sealed box 20, reducing the probability of ice forming at the equipment interface, valves and flanges, thereby reducing the probability of jamming of the moving parts of the valves (relative rotation of valve stem and valve body) and the probability of decreased sealing at the equipment interface and flange connection. It should be noted that the dehumidifier 21 and humidity sensor 22 are electrically connected to the same external controller to realize automatic dehumidification operation. In addition, it should be noted that the general gas supply system is equipped with a cryogenic valve and an emergency shut-off valve on the drain line 2, and a filter, safety valve, flow meter, pressure sensor and flame arrestor on the pressure regulating line 6. The above-mentioned valves and sensors are existing components of the fuel gas supply system, and their connection relationship is also existing technology, so this application will not elaborate further.

[0036] Please see Figure 1 , Figure 8 , Figure 9 and Figure 10 A sealing door 2001 is hinged to the front end of the sealing box 20. A pair of partitions 27 are fixedly connected to the inner wall of the sealing box 20. An upper exhaust groove 2701 is opened on the upper part of the partition 27, and a lower exhaust groove 2702 is opened at its lower end. A mesh plate 28 is fixedly connected between the pair of partitions 27. A heating element 18 is provided below the mesh plate 28. The inlet end of the heating element 18 is connected to the main water inlet pipe 9 through the third water inlet branch pipe 17, and the outlet end of the heating element 18 is connected to the main water return pipe 12 through the third water outlet branch pipe 19.

[0037] Specifically, circulating hot water is injected into the third inlet branch pipe 17 through the main inlet pipe 9, and then into the heating radiator 18. The heating radiator 18 heats the air between a pair of partitions 27. The heated air rises and the rising hot air forces the upper cold air through the upper exhaust groove 2701 into the cavity between the partition 27 and the sealed box 20. Under the continuous compression of the upper hot air, it enters the space below the mesh plate 28 through the lower exhaust groove 2702, so that the air can flow fully through the dehumidifier 21 to dehumidify the air and improve the dehumidification speed and effect. It should be noted that the heating radiator 18 is a serpentine coil.

[0038] Compared to traditional gas supply systems, this invention uses a sealed box 20 to seal the valves and flanges on the pipeline, reducing the probability of environmental moisture coming into contact with the valves and flanges. This reduces the probability of ice forming at equipment interfaces and on the outer walls of valves and flanges, thereby reducing the probability of moving parts of the valves getting stuck and the probability of reduced sealing at equipment interfaces and flange connections. In addition, the dehumidifier 21 reduces the humidity inside the sealed box 20, further reducing the probability of ice forming on valves and flanges. Combined with the partition 27, this allows airflow to circulate within the sealed box 20, improving dehumidification speed and effectiveness.

[0039] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. An LNG fuel supply system for ultra-large container ships, characterized in that, Includes a storage tank (1); the storage tank (1) is connected to an air-temperature vaporizer (3) via a drain pipe (2), the air-temperature vaporizer (3) is connected to a water bath vaporizer (5) via an exhaust pipe (4), and the water bath vaporizer (5) is connected to the fuel inlet of an engine (7) via a pressure regulating pipe (6). The water bath vaporizer (5) includes a shell (501), and a heat exchange tube assembly (502) is provided inside the shell (501). The lower end of the heat exchange tube assembly (502) is connected to the outlet of the exhaust pipe (4), and the upper end of the heat exchange tube assembly (502) is connected to the inlet of the pressure regulating pipe (6). Multiple linearly equidistant heat exchange fins (503) are fixedly connected to the outer wall of the heat exchange tube assembly (502). An electric heating tube (508) is fixedly connected to the inner wall of the shell (501). The shell (501) is filled with circulating water, and the electric heating tube (508) is used to heat the circulating water inside the shell (501). The right end of the outer shell (501) is fixedly connected to a first water inlet connector (506), the first water inlet connector (506) is fixedly connected to a first water inlet branch pipe (10), the right end of the first water inlet branch pipe (10) is fixedly connected to a main water inlet pipe (9), the right end of the main water inlet pipe (9) is fixedly connected to the outlet of the cylinder liner (8), the left end of the outer shell (501) is fixedly connected to a first water outlet connector (507), the left end of the first water outlet connector (507) is fixedly connected to a first water outlet branch pipe (11), the left end of the first water outlet branch pipe (11) is fixedly connected to a return water main pipe (12), the right end of the return water main pipe (12) is fixedly connected to the water inlet of the cylinder liner (8), and a hot water circulation pump (13) is fixedly connected to the return water main pipe (12). The hot water circulation pump (13) makes the hot water circulate between the cylinder liner (8) and the water bath vaporizer (5).

2. The LNG fuel supply system for ultra-large container ships according to claim 1, characterized in that, The first water inlet connector (506) and the first water outlet connector (507) are symmetrically arranged on both sides of the outer shell (501). A pair of symmetrically arranged dispersion plates (504) are provided on the outer side of the heat exchange fins (503). Both dispersion plates (504) are fixedly connected to the inner wall of the outer shell (501). The dispersion plates (504) are arranged opposite to the first water inlet connector (506). Multiple equally spaced dispersion grooves (505) are opened on the dispersion plates (504). The gaps between the dispersion grooves (505) and the adjacent heat exchange fins (503) are arranged opposite to each other.

3. The LNG fuel supply system for ultra-large container ships according to claim 2, characterized in that, The outer shell (501) is a hollow rectangular box, the dispersion plate (504) is a rectangular plate, and a pair of dispersion plates (504) divide the inner cavity of the outer shell (501) into three cavities. The adjacent cavities are connected by a dispersion groove (505), which is a strip-shaped through groove.

4. The LNG fuel supply system for ultra-large container ships according to claim 1, characterized in that, The pressure regulating pipeline (6) is fixedly connected to a primary pressure reducing valve (23) and a secondary pressure reducing valve (24). A heating cylinder (15) is fixedly sleeved on the pipe section between the primary pressure reducing valve (23) and the secondary pressure reducing valve (24) of the pressure regulating pipeline (6). The water inlet end of the heating cylinder (15) is fixedly connected to a second water inlet branch pipe (14). The end of the second water inlet branch pipe (14) away from the heating cylinder (15) is connected to the main water inlet pipe (9). The water outlet end of the heating cylinder (15) is fixedly connected to a second water outlet branch pipe (16). The end of the second water outlet branch pipe (16) away from the heating cylinder (15) is fixedly connected to the main water return pipe (12).

5. The LNG fuel supply system for ultra-large container ships according to claim 4, characterized in that, The heating cylinder (15) includes a cylinder body (1501), which is fixedly sleeved on the pressure regulating pipe (6) and surrounds it to form an annular cavity. A spiral guide plate (1504) is fixedly connected to the inner wall of the annular cavity. A second water inlet connector (1502) is fixedly connected to the upper end of the cylinder body (1501). The second water inlet connector (1502) is fixedly connected to the second water inlet branch pipe (14). A second water outlet connector (1503) is fixedly connected to the lower end of the cylinder body (1501). The second water outlet connector (1503) is fixedly connected to the second water outlet branch pipe (16).

6. The LNG fuel supply system for ultra-large container ships according to claim 4, characterized in that, The exhaust pipe (4) near the outlet end of the air-temperature vaporizer (3) is fixedly connected to a first temperature sensor (25), which is used to detect the temperature of the natural gas after it has been vaporized by the air-temperature vaporizer (3). The pressure regulating pipe (6) near the outlet end of the water bath vaporizer (5) is fixedly connected to a second temperature sensor (26), which is used to detect the temperature of the natural gas before it enters the first-stage pressure reducing valve (23). The pressure regulating pipe (6) located at the outlet end of the second-stage pressure reducing valve (24) is fixedly connected to a third temperature sensor (29), which is used to detect the temperature of the natural gas entering the engine (7).

7. The LNG fuel supply system for ultra-large container ships according to claim 1, characterized in that, The gas supply system also includes a sealed box (20), a drain pipe (2) that is fixedly inserted through the sealed box (20) and the valves and flanges installed on it are all located inside the sealed box (20), the air temperature vaporizer (3) is fixed to the outer wall of the sealed box (20) by a mounting bracket, the valves and flanges installed on the exhaust pipe (4) are all installed inside the sealed box (20), the water bath vaporizer (5) is fixedly connected to the inner wall of the sealed box (20) by a mounting bracket, the valves and flanges on the pressure regulating pipe (6) are all installed inside the sealed box (20), and a dehumidifier (21) and a humidity sensor (22) are fixedly connected to the bottom wall of the sealed box (20).

8. The LNG fuel supply system for ultra-large container ships according to claim 7, characterized in that, The sealing box (20) is hinged to a sealing door (2001) at the front end. A pair of partitions (27) are fixedly connected to the inner wall of the sealing box (20). The upper part of the partition (27) is provided with an upper exhaust groove (2701), and the lower end of the partition (27) is provided with a lower exhaust groove (2702). A mesh plate (28) is fixedly connected between the pair of partitions (27). A heating bar (18) is provided below the mesh plate (28). The inlet end of the heating bar (18) is connected to the main water inlet pipe (9) through the third water inlet branch pipe (17), and the outlet end of the heating bar (18) is connected to the main water return pipe (12) through the third water outlet branch pipe (19).

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