LNG ship cylinder oil system and redundancy design method thereof

Abstract

The application discloses an LNG ship cylinder oil system and a redundancy design method thereof, which comprises the following steps: a main engine cylinder oil system is designed on the left and right sides of a ship, respectively; and the main engine cylinder oil systems on the left and right sides are connected through a communication pipe. When the ship is normally operated, the main engine cylinder oil systems on the left and right sides are independently operated; when a single main engine cylinder oil system or a single device fails, the normal operation of the two main engines can still be maintained by using the communication pipe, the cylinder oil systems on the left and right sides form redundancy, and thus the safety of the cylinder oil system is improved.

Description

Technical Field

[0001] This invention relates to the field of shipbuilding technology, and in particular to an LNG ship cylinder oil system and its redundancy design method. Background Technology

[0002] LNG carriers transporting methane at -163°C are essentially liquid bombs at sea. To mitigate these risks, LNG carriers are typically designed with two propulsion systems. Classification societies require that even if one propulsion system fails, the remaining power should still allow the vessel to navigate at low speeds. This necessitates a certain degree of redundancy in the ship's design. When a low-speed diesel engine is operating, cylinder oil is periodically injected into the cylinders to lubricate the moving pistons. For an LNG carrier to consistently provide propulsion without being affected by the failure of a single device or system, redundancy in the cylinder oil system is essential.

[0003] Therefore, how to design a redundancy design method for the cylinder oil system of LNG ships has become an urgent problem to be solved. Summary of the Invention

[0004] In view of this, the present invention provides an LNG ship cylinder oil system and its redundancy design method, which can ensure that the ship propulsion system can still operate normally under the failure of a single device or a single system, thus ensuring the safe and reliable navigation of LNG ships at sea.

[0005] An LNG carrier cylinder oil system based on redundancy design includes a cylinder oil storage tank, a main oil supply pipe connected to the outlet of the cylinder oil storage tank, a first oil supply branch pipe and a second oil supply branch pipe connected to the end of the main oil supply pipe, a first cylinder oil daily storage tank connected to the first oil supply branch pipe, a second cylinder oil daily storage tank connected to the second oil supply branch pipe, a first main engine connected to the first cylinder oil daily storage tank via a first connecting pipe, and a second main engine connected to the second cylinder oil daily storage tank via a second connecting pipe.

[0006] The main oil pipeline is equipped with a first shut-off valve.

[0007] The first oil supply branch pipe is equipped with a first control valve group and a first cylinder oil pump, the second oil supply branch pipe is equipped with a second control valve group and a second cylinder oil pump, and a connecting pipe is connected between the first oil supply branch pipe and the second oil supply branch pipe. The connecting pipe is equipped with a sixth shut-off valve, which is in the closed state when the cylinder oil system is working normally.

[0008] The first cylinder oil daily use cabinet is equipped with a first level switch for detecting the cylinder oil level in the cabinet, and the first level switch forms a control interlock with the first cylinder oil pump. The second cylinder oil daily use cabinet is equipped with a second level switch for detecting the cylinder oil level in the cabinet, and the second level switch forms a control interlock with the second cylinder oil pump.

[0009] Preferably, the first control valve group includes a second shut-off valve and a first shut-off check valve, the second shut-off valve and the first shut-off check valve being respectively installed on the oil inlet side and oil outlet side of the first cylinder oil pump.

[0010] The second control valve group includes a fourth shut-off valve and a second shut-off check valve. The fourth shut-off valve and the second shut-off check valve are respectively located on the oil inlet side and oil outlet side of the second cylinder oil pump. The connection node between the connecting pipe and the first oil supply branch pipe and the second oil supply branch pipe is located downstream of the first shut-off check valve and the second shut-off check valve.

[0011] Preferably, the connection node between the connecting pipe and the first oil supply branch pipe and the second oil supply branch pipe is close to the valve outlet of the first shut-off check valve and the second shut-off check valve.

[0012] Preferably, when the ship is operating normally, the cylinder oil in the cylinder oil storage tank is supplied to the first main engine and the second main engine through the first cylinder oil path and the second cylinder oil path, respectively.

[0013] When the first cylinder oil pump fails, the sixth shut-off valve is opened and the first control valve group is closed, and the cylinder oil in the cylinder oil storage tank is delivered to the first host through the third cylinder oil path.

[0014] When the second cylinder oil pump malfunctions, the sixth shut-off valve is opened and the second control valve group is closed, and the cylinder oil in the cylinder oil storage tank is delivered to the second main unit through the fourth cylinder oil path.

[0015] Preferably, the first cylinder oil path is: cylinder oil storage tank → main oil supply pipe → first branch oil supply pipe → first cylinder oil daily use tank → first connecting pipe → first main unit;

[0016] The oil path for the second cylinder is: Cylinder oil storage tank → Main oil supply pipe → Second oil supply branch pipe →

[0017] Second cylinder oil daily use cabinet → Second connecting pipe → Second main unit;

[0018] The oil path for the third cylinder is: cylinder oil storage tank → main oil supply pipe → fourth shut-off valve, second cylinder oil pump and second shut-off check valve of the second oil supply branch pipe → connecting pipe → first oil supply branch pipe → first cylinder oil day cabinet → first connecting pipe → first main unit.

[0019] The oil path for the fourth cylinder is as follows: cylinder oil storage tank → main oil supply pipe → second shut-off valve, first cylinder oil pump and first shut-off check valve of the first oil supply branch pipe → connecting pipe → second oil supply branch pipe → second cylinder oil day cabinet → second connecting pipe → second main unit.

[0020] Preferably, the cylinder oil storage tank, the first main engine, and the second main engine are all arranged in the engine room. The first main engine is located in the engine room near the port side, and the second main engine is located in the engine room near the starboard side. The first cylinder oil daily storage tank and the second cylinder oil daily storage tank are arranged at the same height on both sides of the centerline of the ship. The arrangement height of the first cylinder oil daily storage tank and the second cylinder oil daily storage tank is higher than the arrangement height of the cylinder oil storage tank, the first main engine, and the second main engine. The arrangement height of the first cylinder oil pump and the second cylinder oil pump is equal to the arrangement height of the cylinder oil storage tank.

[0021] Preferably, a third shut-off valve is provided on the first connecting pipe, and a fifth shut-off valve is provided on the second connecting pipe.

[0022] A redundancy design method for an LNG carrier cylinder oil system includes the following steps:

[0023] S1, a first cylinder oil day tank and a second cylinder oil day tank are respectively installed on both sides of the centerline in the engine room. The cylinder oil storage tank is located below the first cylinder oil day tank and the second cylinder oil day tank. The first main engine is installed in the engine room near the port side and its height is lower than the first cylinder oil day tank. The second main engine is installed in the engine room near the starboard side and its height is lower than the second cylinder oil day tank.

[0024] S2, connect a horizontal main oil pipe to the oil outlet of the cylinder oil storage tank, lay a first branch oil pipe horizontally at the end of the main oil pipe toward the left bulkhead, lay the first branch oil pipe horizontally to the left bulkhead and vertically upward along the tank surface until it is connected to the oil inlet of the first cylinder oil storage tank, and then connect the oil outlet of the first cylinder oil storage tank to the oil inlet of the first main engine through the first connecting pipe.

[0025] Meanwhile, a second oil supply branch pipe is laid horizontally at the end of the main oil supply pipe toward the right bulkhead. The second oil supply branch pipe is laid horizontally to the right bulkhead and then vertically upward along the tank surface until it is connected to the oil inlet of the second cylinder oil day tank. Then the oil outlet of the second cylinder oil day tank is connected to the oil inlet of the second main engine through the second connecting pipe.

[0026] When laying the first oil branch pipe, the first control valve group and the first cylinder oil pump are installed on the pipeline. The first cylinder oil pump and the cylinder oil storage tank are arranged at the same height.

[0027] When laying the second oil branch pipe, a second control valve group and a second cylinder oil pump are installed on the pipeline. The second cylinder oil pump and the cylinder oil storage tank are arranged at the same height.

[0028] A connecting pipe is connected between the first oil supply branch and the second oil supply branch, and a sixth shut-off valve is installed on the connecting pipe;

[0029] S3, When the ship is operating normally, the cylinder oil in the cylinder oil storage tank is delivered to the first main engine and the second main engine through the first cylinder oil path and the second cylinder oil path, respectively.

[0030] When the first cylinder oil pump fails, the sixth shut-off valve is opened and the first control valve group is closed, and the cylinder oil in the cylinder oil storage tank is delivered to the first host through the third cylinder oil path.

[0031] When the second cylinder oil pump malfunctions, the sixth shut-off valve is opened and the second control valve group is closed, and the cylinder oil in the cylinder oil storage tank is delivered to the second main unit through the fourth cylinder oil path.

[0032] Preferably, the first cylinder oil path is: cylinder oil storage tank → main oil supply pipe → first branch oil supply pipe → first cylinder oil daily use tank → first connecting pipe → first main unit;

[0033] The oil path for the second cylinder is: Cylinder oil storage tank → Main oil supply pipe → Second oil supply branch pipe →

[0034] Second cylinder oil daily use cabinet → Second connecting pipe → Second main unit;

[0035] The oil path for the third cylinder is: cylinder oil storage tank → main oil supply pipe → fourth shut-off valve, second cylinder oil pump and second shut-off check valve of the second oil supply branch pipe → connecting pipe → first oil supply branch pipe → first cylinder oil day cabinet → first connecting pipe → first main unit.

[0036] The oil path for the fourth cylinder is as follows: cylinder oil storage tank → main oil supply pipe → second shut-off valve, first cylinder oil pump and first shut-off check valve of the first oil supply branch pipe → connecting pipe → second oil supply branch pipe → second cylinder oil day cabinet → second connecting pipe → second main unit.

[0037] The beneficial effects of this invention are:

[0038] This invention designs a main engine cylinder oil system on each of the port and starboard sides and connects them via a connecting pipe. During normal ship operation, the main engine cylinder oil systems on the port and starboard sides operate independently. When a single main engine cylinder oil system or a single device fails, the connecting pipe can still maintain the normal operation of both main engines, thus creating redundancy in the cylinder oil systems on both sides and improving the safety of the cylinder oil system.

[0039] Furthermore, by establishing a control interlock between the first liquid level switch and the first cylinder oil pump, and between the second liquid level switch and the second cylinder oil pump, this invention can automatically replenish the oil level in the two cylinder daily use tanks, ensuring the normal operation of the main unit. Moreover, the cylinder oil system has fewer devices, saving costs and making it easier for crew members to operate. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the cylinder oil system of an LNG ship.

[0042] The labels in the diagram mean:

[0043] 1. Cylinder oil storage tank; 2. First shut-off valve; 3. Second shut-off valve; 4. First cylinder oil pump; 5. First shut-off check valve; 6. First cylinder oil daily use cabinet; 7. First liquid level switch; 8. Third shut-off valve; 9. First main unit; 10. Fourth shut-off valve; 11. Second cylinder oil pump; 12. Second shut-off check valve; 14. Second cylinder oil daily use cabinet; 15. Second liquid level switch; 16. Fifth shut-off valve; 17. Second main unit; 18. Sixth shut-off valve; 19. Main oil supply pipe; 20. First oil supply branch pipe; 21. Second oil supply branch pipe; 22. First connecting pipe; 23. Connecting pipe. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0045] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0046] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms and should not be construed as indicating or implying relative importance. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0047] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", "vertical", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0048] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical connection or internal connection between two components. They can be direct connection or indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0049] The present application will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0050] This invention provides an LNG ship cylinder oil system based on redundancy design, including a cylinder oil storage tank 1, an oil main pipe 18 connected to the outlet of the cylinder oil storage tank 1, a first oil branch pipe 19 and a second oil branch pipe 20 connected to the end of the oil main pipe 18, a first cylinder oil daily storage tank 6 connected to the first oil branch pipe 19, a second cylinder oil daily storage tank 13 connected to the second oil branch pipe 20, a first main unit 9 connected to the first cylinder oil daily storage tank 6 via a first connecting pipe 21, and a second main unit 16 connected to the second cylinder oil daily storage tank 13 via a second connecting pipe 22.

[0051] The main oil pipeline 18 is equipped with a first shut-off valve 2, which is used to control the opening and closing of the main oil pipeline 18.

[0052] The first oil supply branch pipe 19 is equipped with a first control valve group and a first cylinder oil pump 4. The first control valve group is used to control the opening and closing of the first oil supply branch pipe 19. In this embodiment, the first control valve group includes a second shut-off valve 3 and a first shut-off check valve 5, which are respectively installed on the oil inlet side and the oil outlet side of the first cylinder oil pump 4.

[0053] The second oil supply branch pipe 20 is equipped with a second control valve group and a second cylinder oil pump 11. The second control valve group is used to control the opening and closing of the pipeline of the second oil supply branch pipe 20. In this embodiment, the second control valve group includes a fourth shut-off valve 10 and a second shut-off check valve 12, which are located on the oil inlet side and the oil outlet side of the second cylinder oil pump 11, respectively.

[0054] A connecting pipe 23 connects the first oil supply branch pipe 19 and the second oil supply branch pipe 20. Specifically, the connection point between the connecting pipe 23 and the first oil supply branch pipe 19 and the second oil supply branch pipe 20 is located downstream of the first shut-off check valve 5 and the second shut-off check valve 12.

[0055] Preferably, the connection node between the connecting pipe 23 and the first oil supply branch pipe 19 and the second oil supply branch pipe 20 is close to the valve outlet of the first shut-off check valve 5 and the second shut-off check valve 12.

[0056] The connecting pipe 23 is equipped with a sixth shut-off valve 17, which is used to control the opening and closing of the connecting pipe 23. When the cylinder oil system is working normally, the sixth shut-off valve 17 is in the closed state. When a single cylinder oil system fails, the sixth shut-off valve 17 is opened to make the cylinder oil systems on the port and starboard sides redundant, so as to ensure the safety of the cylinder oil system.

[0057] A third shut-off valve 8 is provided on the first connecting pipe 21, and a fifth shut-off valve 15 is provided on the second connecting pipe 22.

[0058] The first cylinder oil daily use cabinet 6 is equipped with a first level switch 7 for detecting the cylinder oil level in the cabinet. The first level switch 7 and the first cylinder oil pump 4 form a control interlock. The second cylinder oil daily use cabinet 13 is equipped with a second level switch 14 for detecting the cylinder oil level in the cabinet. The second level switch 14 and the second cylinder oil pump 11 form a control interlock.

[0059] During normal ship operation, the first level switch 7 monitors the cylinder oil level inside the first cylinder oil daily tank 6 in real time. When the level in the first cylinder oil daily tank 6 is lower than the set value, the first level switch 7 sends a signal to start the first cylinder oil pump 4 to replenish cylinder oil to the first cylinder oil daily tank 6. When the level is higher than the normal level, the first level switch 7 sends a signal to stop the first cylinder oil pump 4, thus realizing the automatic replenishment function of cylinder oil inside the first cylinder oil daily tank 6. Therefore, during normal ship operation, the cylinder oil in the cylinder oil storage tank 1 is transported to the first main engine 9 through the first cylinder oil path, which is: cylinder oil storage tank 1 → main oil pipe 18 → first branch oil pipe 19 → first cylinder oil daily tank 6 → first connecting pipe 21 → first main engine 9.

[0060] Meanwhile, the second liquid level switch 14 also monitors the liquid level of the cylinder oil inside the second cylinder oil daily storage tank 13 in real time. When the liquid level in the second cylinder oil daily storage tank 13 is lower than the set value, the second liquid level switch 14 sends a signal to start the second cylinder oil pump 11 to replenish the cylinder oil in the second cylinder oil daily storage tank 13. When the liquid level is higher than the normal liquid level, the second liquid level switch 14 sends a signal to stop the second cylinder oil pump 11, realizing the automatic replenishment function of the cylinder oil inside the second cylinder oil daily storage tank 13. Therefore, during normal operation of the ship, the cylinder oil in the cylinder oil storage tank 1 is transported to the second main engine 16 through the second cylinder oil path. The second cylinder oil path is: cylinder oil storage tank 1 → main oil pipe 18 → second branch oil pipe 20 → second cylinder oil daily storage tank 13 → second connecting pipe 22 → second main engine 16.

[0061] When the first cylinder oil pump 4 malfunctions, the first cylinder oil path fails. At this time, the sixth shut-off valve 17 is opened, and the second shut-off valve 3 and the first shut-off check valve 5 are closed. The cylinder oil in the cylinder oil storage tank 1 is then supplied to the first main unit 9 via the third cylinder oil path. The third cylinder oil path is as follows: cylinder oil storage tank 1 → main oil pipe 18 → fourth shut-off valve 10 of the second oil branch pipe, second cylinder oil pump 11, and second shut-off check valve 12 → connecting pipe 23 → first oil branch pipe → first cylinder oil storage tank 6 → first connecting pipe 21 → first main unit 9. Under this fault condition, the second cylinder oil path continues to operate normally.

[0062] When the second cylinder oil pump 11 malfunctions, the second cylinder oil path fails. At this time, the sixth shut-off valve 17 is opened, and the fourth shut-off valve 10 and the second shut-off check valve 12 are closed. The cylinder oil in the cylinder oil storage tank 1 is then supplied to the second main unit 16 through the fourth cylinder oil path. The fourth cylinder oil path is as follows: cylinder oil storage tank 1 → main oil supply pipe 18 → second shut-off valve 3, first cylinder oil pump 4, and first shut-off check valve 5 of the first oil supply branch pipe → connecting pipe 23 → second oil supply branch pipe → second cylinder oil storage tank 13 → second connecting pipe 22 → second main unit 16. Under this fault condition, the first cylinder oil path continues to operate normally.

[0063] This invention also provides a redundancy design method for an LNG ship cylinder oil system, specifically including the following steps:

[0064] S1, a first cylinder oil day tank 6 and a second cylinder oil day tank 13 are respectively installed on both sides of the centerline inside the engine room, and the first cylinder oil day tank 6 and the second cylinder oil day tank 13 are arranged at the same height.

[0065] Then, the cylinder oil storage cabinet 1 is placed below the first cylinder oil daily cabinet 6 and the second cylinder oil daily cabinet 13, with the cylinder oil storage cabinet 1 located between the first cylinder oil daily cabinet 6 and the second cylinder oil daily cabinet 13.

[0066] The first main engine 9 is installed in the engine room near the port side and its height is lower than that of the first cylinder oil day cabinet 6. The second main engine 16 is installed in the engine room near the starboard side and its height is lower than that of the second cylinder oil day cabinet 13.

[0067] S2, connect a horizontal oil supply main pipe 18 to the oil outlet of the cylinder oil storage tank 1, lay a first oil supply branch pipe 19 horizontally at the end of the oil supply main pipe 18 toward the left bulkhead, lay the first oil supply branch pipe 19 horizontally to the left bulkhead and vertically upward along the tank surface until it is connected to the oil inlet of the first cylinder oil daily use tank 6, and then connect the oil outlet of the first cylinder oil daily use tank 6 to the oil inlet of the first main engine 9 through the first connecting pipe 21.

[0068] Meanwhile, a second oil supply branch pipe 20 is laid horizontally at the end of the main oil supply pipe 18 toward the right bulkhead. The second oil supply branch pipe 20 is laid horizontally to the right bulkhead and then vertically upward along the tank surface until it is connected to the oil inlet of the second cylinder oil day tank 13. Then the oil outlet of the second cylinder oil day tank 13 is connected to the oil inlet of the second main engine 16 through the second connecting pipe 22.

[0069] A connecting pipe 23 is connected between the first oil supply branch pipe 19 and the second oil supply branch pipe 20. The connection node between the connecting pipe 23 and the first oil supply branch pipe 19 and the second oil supply branch pipe 20 is close to the valve outlet of the first shut-off check valve 5 and the second shut-off check valve 12. A sixth shut-off valve 17 is installed on the connecting pipe 23.

[0070] When laying the main oil pipeline 18, install the first shut-off valve 2 on its pipeline.

[0071] When laying the first oil branch pipe 19, a second shut-off valve 3, a first shut-off check valve 5 and a first cylinder oil pump 4 are installed on the pipeline. The second shut-off valve 3 is located on the oil inlet side of the first cylinder oil pump 4, and the first shut-off check valve 5 is located on the oil outlet side of the first cylinder oil pump 4. The first cylinder oil pump 4 and the cylinder oil storage tank 1 are arranged at the same height.

[0072] When laying the second oil branch pipe 20, a fourth shut-off valve 10, a second shut-off check valve 12, and a second cylinder oil pump 11 are installed on the pipeline. The fourth shut-off valve 10 is located on the oil inlet side of the second cylinder oil pump 11, and the second shut-off check valve 12 is located on the oil outlet side of the second cylinder oil pump 11. The second cylinder oil pump 11 and the cylinder oil storage tank 1 are arranged at the same height.

[0073] When laying the first connecting pipe 21, install the third shut-off valve 8 on its pipeline.

[0074] When laying the second connecting pipe 22, install the fifth shut-off valve 15 on its pipeline.

[0075] S3, When the ship is operating normally, the cylinder oil in the cylinder oil storage tank 1 is supplied to the first main engine 9 and the second main engine 16 through the first cylinder oil path and the second cylinder oil path, respectively.

[0076] When the first cylinder oil pump 4 fails, the sixth shut-off valve 17 is opened and the first control valve group is closed. The cylinder oil in the cylinder oil storage tank 1 is transported to the first host 9 through the third cylinder oil path and to the second host 16 through the second cylinder oil path.

[0077] When the second cylinder oil pump 11 malfunctions, the sixth shut-off valve 17 is opened and the second control valve group is closed. The cylinder oil in the cylinder oil storage tank 1 is transported to the first host 9 through the first cylinder oil path and to the second host 16 through the fourth cylinder oil path.

[0078] Meanwhile, since the first liquid level switch 7 and the first cylinder oil pump 4 are interlocked, and the second liquid level switch 14 and the second cylinder oil pump 11 are interlocked, when supplying cylinder oil to the main unit, the first liquid level switch 7 and the second liquid level switch 14 detect the liquid level in their respective cylinder oil daily use tanks in real time, and control the start and stop of their respective corresponding cylinder oil pumps according to the liquid level changes to automatically replenish the oil in their respective cylinder oil daily use tanks.

[0079] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A LNG carrier cylinder oil system based on redundancy design, characterized by, The cylinder oil storage tank (1), the oil supply main pipe (18) connected to the outlet of the cylinder oil storage tank (1), the first oil supply branch pipe (19) and the second oil supply branch pipe (20) connected to the end of the oil supply main pipe (18), the first cylinder oil daily use tank (6) connected to the first oil supply branch pipe (19), the second cylinder oil daily use tank (13) connected to the second oil supply branch pipe (20), the first main engine (9) connected to the first cylinder oil daily use tank (6) through the first connecting pipe (21), and the second main engine (16) connected to the second cylinder oil daily use tank (13) through the second connecting pipe (22), The first stop valve (2) is arranged on the oil supply main pipe (18), The first control valve group and the first cylinder oil pump (4) are arranged on the first oil supply branch pipe (19), and the second control valve group and the second cylinder oil pump (11) are arranged on the second oil supply branch pipe (20), the communication pipe (23) is connected between the first oil supply branch pipe (19) and the second oil supply branch pipe (20), the sixth stop valve (17) is arranged on the communication pipe (23), and the sixth stop valve (17) is in a closed state when the cylinder oil system is normally working; The first liquid level switch (7) is arranged in the first cylinder oil daily use tank (6) to detect the liquid level of the cylinder oil in the tank, and the first liquid level switch (7) and the first cylinder oil pump (4) form a control interlock, the second liquid level switch (14) is arranged in the second cylinder oil daily use tank (13) to detect the liquid level of the cylinder oil in the tank, and the second liquid level switch (14) and the second cylinder oil pump (11) form a control interlock.

2. The LNG carrier cylinder oil system based on a redundancy design according to claim 1, characterized in that, The first control valve group includes the second stop valve (3) and the first stop check valve (5), the second stop valve (3) and the first stop check valve (5) are arranged on the pipelines on the oil inlet side and the oil outlet side of the first cylinder oil pump (4) respectively, The second control valve group includes the fourth stop valve (10) and the second stop check valve (12), the fourth stop valve (10) and the second stop check valve (12) are arranged on the pipelines on the oil inlet side and the oil outlet side of the second cylinder oil pump (11) respectively, and the connection node of the communication pipe (23) and the first oil supply branch pipe (19) and the second oil supply branch pipe (20) is located downstream of the first stop check valve (5) and the second stop check valve (12).

3. The LNG carrier cylinder oil system based on a redundancy design according to claim 2, characterized in that, The connection node of the communication pipe (23) and the first oil supply branch pipe (19) and the second oil supply branch pipe (20) is close to the valve outlets of the first stop check valve (5) and the second stop check valve (12).

4. The LNG carrier cylinder oil system based on the redundancy design according to claim 2, characterized by, When the ship is normally running, the cylinder oil in the cylinder oil storage tank (1) is delivered to the first main engine (9) and the second main engine (16) through the first cylinder oil path and the second cylinder oil path respectively, When the first cylinder oil pump (4) fails, the sixth stop valve (17) is opened and the first control valve group is closed, and the cylinder oil in the cylinder oil storage tank (1) is delivered to the first main engine (9) through the third cylinder oil path; When the second cylinder oil pump (11) fails, the sixth stop valve (17) is opened and the second control valve group is closed, and the cylinder oil in the cylinder oil storage tank (1) is delivered to the second main engine (16) through the fourth cylinder oil path.

5. The LNG carrier cylinder oil system based on a redundancy design according to claim 4, characterized in that, The first cylinder oil path is: cylinder oil storage tank (1)→ oil supply main pipe (18)→ first oil supply branch pipe (19)→ first cylinder oil daily use tank (6)→ first connecting pipe (21)→ first main engine (9); The second cylinder oil path is: cylinder oil storage tank (1)→ oil supply main pipe (18)→ second oil supply branch pipe (20)→ second cylinder oil daily use tank (13)→ second connecting pipe (22)→ second main engine (16); The third cylinder oil path is: cylinder oil storage tank (1)→ oil supply main pipe (18)→ fourth stop valve (10), second cylinder oil pump (11) and second stop check valve (12) of the second oil supply branch pipe→ communication pipe (23)→ first oil supply branch pipe→ first cylinder oil daily use tank (6)→ first connecting pipe (21)→ first main engine (9); The fourth cylinder oil path is: cylinder oil storage tank (1)→ oil supply main pipe (18)→ second stop valve (3), first cylinder oil pump (4) and first stop check valve (5) of the first oil supply branch pipe→ communication pipe (23)→ second oil supply branch pipe→ second cylinder oil daily use tank (13)→ second connecting pipe (22)→ second main engine (16).

6. The LNG carrier cylinder oil system based on redundancy design according to claim 1 or 4, characterized in that, The cylinder oil storage tank (1), the first main engine (9) and the second main engine (16) are arranged in the engine room, the first main engine (9) is arranged at a position close to the port side in the engine room, the second main engine (16) is arranged at a position close to the starboard side in the engine room, the first cylinder oil daily use tank (6) and the second cylinder oil daily use tank (13) are arranged at the same height position on both sides of the centerline of the ship, the arrangement height of the first cylinder oil daily use tank (6) and the second cylinder oil daily use tank (13) is higher than that of the cylinder oil storage tank (1), the first main engine (9) and the second main engine (16), and the arrangement height of the first cylinder oil pump (4) and the second cylinder oil pump (11) is equal to that of the cylinder oil storage tank (1).

7. The LNG carrier cylinder oil system based on redundancy design of claim 1, wherein, The third stop valve (8) is arranged on the first connecting pipe (21), and the fifth stop valve (15) is arranged on the second connecting pipe (22).

8. A redundancy design method for an LNG carrier cylinder oil system, characterized by, Specifically, the following steps are included: S1, first cylinder oil daily use tank (6) and second cylinder oil daily use tank (13) are arranged on both sides of the centerline of the ship in the engine room, the cylinder oil storage tank (1) is arranged below the first cylinder oil daily use tank (6) and the second cylinder oil daily use tank (13), the first main engine (9) is arranged at a position close to the port side in the engine room and has a height lower than that of the first cylinder oil daily use tank (6), and the second main engine (16) is arranged at a position close to the starboard side in the engine room and has a height lower than that of the second cylinder oil daily use tank (13); S2, a horizontal oil supply main pipe (18) is connected to the oil outlet of the cylinder oil storage tank (1), a first oil supply branch pipe (19) is horizontally laid at the end of the oil supply main pipe (18) towards the left bulkhead, the first oil supply branch pipe (19) is horizontally laid to the left bulkhead and vertically upwards along the deck until connected to the oil inlet of the first cylinder oil daily use tank (6), and then the oil outlet of the first cylinder oil daily use tank (6) is connected to the oil inlet of the first main engine (9) through a first connecting pipe (21); Meanwhile, a second oil supply branch pipe (20) is horizontally laid at the end of the oil supply main pipe (18) towards the right bulkhead, and the second oil supply branch pipe (20) is horizontally laid to the right bulkhead and vertically upwards along the deck until connected with the oil inlet of the second cylinder oil daily use tank (13), and then the oil outlet of the second cylinder oil daily use tank (13) is connected with the oil inlet of the second main engine (16) through the second connecting pipe (22); When the first oil supply branch pipe (19) is laid, the first control valve group and the first cylinder oil pump (4) are installed on the pipeline of the first oil supply branch pipe (19), and the first cylinder oil pump (4) is arranged at the same height as the cylinder oil storage tank (1); When the second oil supply branch pipe (20) is laid, the second control valve group and the second cylinder oil pump (11) are installed on the pipeline of the second oil supply branch pipe (20), and the second cylinder oil pump (11) is arranged at the same height as the cylinder oil storage tank (1); The communication pipe (23) is connected between the first oil supply branch pipe (19) and the second oil supply branch pipe (20), and the sixth stop valve (17) is arranged on the communication pipe (23); S3, when the ship is running normally, the cylinder oil in the cylinder oil storage tank (1) is delivered to the first main engine (9) and the second main engine (16) through the first cylinder oil path and the second cylinder oil path respectively, When the first cylinder oil pump (4) fails, the sixth stop valve (17) is opened and the first control valve group is closed, and the cylinder oil in the cylinder oil storage tank (1) is delivered to the first main engine (9) through the third cylinder oil path; When the second cylinder oil pump (11) fails, the sixth stop valve (17) is opened and the second control valve group is closed, and the cylinder oil in the cylinder oil storage tank (1) is delivered to the second main engine (16) through the fourth cylinder oil path.

9. The method of claim 8, wherein, The first cylinder oil path is: cylinder oil storage tank (1)→oil supply main pipe (18)→first oil supply branch pipe (19)→first cylinder oil daily use tank (6)→first connecting pipe (21)→first main engine (9); The second cylinder oil path is: cylinder oil storage tank (1)→oil supply main pipe (18)→second oil supply branch pipe (20)→second cylinder oil daily use tank (13)→second connecting pipe (22)→second main engine (16); The third cylinder oil path is: cylinder oil storage tank (1)→oil supply main pipe (18)→fourth stop valve (10), second cylinder oil pump (11) and second stop check valve (12) of the second oil supply branch pipe→communication pipe (23)→first oil supply branch pipe→first cylinder oil daily use tank (6)→first connecting pipe (21)→first main engine (9); The fourth cylinder oil path is: cylinder oil storage tank (1)→oil supply main pipe (18)→second stop valve (3), first cylinder oil pump (4) and first stop check valve (5) of the first oil supply branch pipe→communication pipe (23)→second oil supply branch pipe→second cylinder oil daily use tank (13)→second connecting pipe (22)→second main engine (16).

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