A liquid tank swaying system, swaying process and control method for LNG bunkering vessels

Abstract

This invention discloses a liquid tank sloshing system, sloshing process, and control method for LNG bunkering vessels. The system includes a liquid tank containing a level detector and a data processor. Sloshing plates are symmetrically installed on both sides of the tank, and each plate is connected to the tank via multiple connecting devices. Each connecting device has a pressure sensor at its end. The data processor is connected to the level detector, pressure sensor, and connecting devices for control. When the sloshing plates are impacted by liquefied natural gas in the tank, a hydraulic rod adjusts the hydraulic damping strength, allowing the plates to reciprocate with the tank's sloshing motion, absorbing the impact. Based on sensor data, the sloshing plates automatically adjust their angle to increase the effective sloshing area. The transverse and longitudinal baffles on the sloshing plates reduce the stress generated by the sloshing impact, improving system stability. The system is adjusted in real-time according to changes in the liquid level and the degree of sloshing within the tank.

Description

Technical Field

[0001] This invention relates to a sway control system and control method, and more particularly to a sway control system, sway control process and control method for LNG bunkering vessels. Background Technology

[0002] LNG is a highly efficient and clean energy source, commonly known as liquefied natural gas. In recent years, under the major trend of energy conservation and emission reduction in my country's shipbuilding industry, LNG ships have developed rapidly and have a promising future. Due to the presence of large liquid tanks within the ship's hold, these ships inevitably experience situations where the tanks are not fully loaded, resulting in free surface areas and causing the LNG inside to sway and slosh. When the external excitation frequency is close to the natural frequency of the tank, even with a small excitation amplitude, the tank will experience strong swaying, causing damage to the hull structure and potentially affecting its stability, leading to serious accidents. Therefore, employing anti-sloshing devices to reduce the risks posed by LNG tank sloshing is essential.

[0003] Currently, the development of LNG liquid tank sloshing control equipment is still in its early stages, and the level of engineering application is low. Conventional sloshing control measures involve adding bulkheads or transverse baffles inside the liquid tank, but these have the following drawbacks: they require high structural strength from the ship and the sloshing control effect is generally poor; as the bunkering vessel operates, the liquid level in the tank gradually decreases, and current sloshing control equipment cannot adjust in a timely manner according to the real-time operating conditions of the bunkering vessel, resulting in an unsatisfactory sloshing control effect; when the ship is in the process of bunkering, conventional sloshing control plates cannot effectively reduce the impact of lateral sloshing of liquefied natural gas in the tank. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to propose a sway control system, sway control process and control method for LNG bunkering vessels, which can increase the effective sway control area of ​​the sway control plate; reduce the stress generated by the swaying impact on the sway control plate itself, and improve the stability of the system.

[0005] Technical solution: The present invention includes a liquid tank, in which a liquid level detector and a data processor are fixedly installed. Swaying plates are symmetrically installed on both sides of the liquid tank. The swaying plates on both sides are connected to the liquid tank through multiple connecting devices. Each connecting device has a pressure sensor at its end. The data processor is controlled and connected to the liquid level detector, the pressure sensor and the connecting devices.

[0006] The oscillation plate is provided with several horizontal and vertical partition plates, which divide the oscillation plate into several small spaces. Each small space of the oscillation plate is provided with a through hole.

[0007] The through holes are tapered holes, and the opening directions of the tapered holes are staggered along the vertical direction.

[0008] The connecting device is a hydraulic control rod, and the cylinder of the hydraulic control rod located on the same side of the liquid tank is slidably connected to the bracket installed in the liquid tank on that side.

[0009] The piston rod in the hydraulic control lever is connected to the oscillation plate through a universal joint, so that the oscillation plate can move back and forth in the liquid tank and can deflect in the lateral and longitudinal directions under the push of multiple hydraulic control levers.

[0010] The data processors are symmetrically arranged on both sides of the liquid tank. Their input terminals are connected to the output terminals of the liquid level detector and the pressure sensor, respectively. The output terminal of the data processor is connected to the control terminal of the hydraulic control rod located on the same side of the liquid tank.

[0011] A sway control process for a liquid tank sway control system used in an LNG bunkering vessel includes the following steps:

[0012] 1) Install the above-mentioned anti-surge system;

[0013] 2) The liquid level detector detects the liquid level in the tank and adjusts the position of the baffle plate relative to the tank according to the liquid level.

[0014] 3) The pressure sensor detects the pressure value on the surface of the sway plate, and adjusts the extension and retraction of the hydraulic control rod according to the pressure value, thereby controlling the deflection direction and angle of the sway plate;

[0015] 4) The pressure sensor detects the pressure value on the surface of the damping plate after the damping plate deflects, and adjusts the damping strength of the hydraulic control rod again based on the pressure value;

[0016] 5) Repeat steps 2) to 4) until the height of the liquid level in the tank reaches the minimum value.

[0017] A control method for a liquid tank oscillation control system for an LNG bunkering vessel includes:

[0018] When the liquid tank is full, the data processor controls the extension and retraction of the hydraulic control rod on the corresponding side to make the extension and retraction of the hydraulic rod the same. At this time, the sway plate is perpendicular to the surface of the liquid tank. The damping of the hydraulic control rod is adjusted according to the data measured by the pressure sensor, so that the sway plate and the free liquid surface in the liquid tank make periodic swaying.

[0019] When the liquid tank is not fully loaded, the data processor controls the extension and retraction of the hydraulic control rod on the corresponding side, so that the swaying plate moves while rotating longitudinally around the central axis, increasing the immersion area of ​​the swaying plate. The data processor adjusts the damping of the hydraulic rod according to the data measured by the pressure sensor, so that the swaying plate follows the free liquid surface in the liquid tank to make periodic swaying.

[0020] When the bunkering vessel is in bunkering operation, the data processor controls the extension and retraction of the hydraulic rod on one side based on the liquid level height and liquid pressure detected by the liquid level detector and pressure sensor, so that the sway plate deflects laterally around the central axis. The damping of the hydraulic control rod is adjusted according to the data measured by the pressure sensor, so that the sway plate follows the free liquid surface in the liquid tank and makes periodic swaying.

[0021] Beneficial effects:

[0022] (1) When the sway plate is impacted by liquefied natural gas in the liquid tank, the hydraulic rod adjusts the hydraulic damping strength to allow the sway plate to reciprocate with the liquid tank, absorbing the impact caused by the liquid swaying. According to the data measured by the sensor, the sway plate automatically adjusts the angle to increase the effective swaying area of ​​the sway plate. The setting of the transverse and longitudinal baffles on the sway plate can reduce the stress generated by the swaying impact on the sway plate itself and improve the stability of the system.

[0023] (2) It can be adjusted in a timely manner according to the real-time changes in the liquid level in the tank and the degree of swaying of the hull, so as to ensure that the liquid level height is always at the lowest value when the tank is swaying, which can greatly improve the swaying effect and thus effectively reduce the damage to the tank wall caused by the swaying of the tank. Attached Figure Description

[0024] Figure 1 This is an overall structural diagram of the present invention;

[0025] Figure 2 This is a schematic diagram of the damping plate structure of the present invention;

[0026] Figure 3 This is a diagram showing the opening structure of the damping plate of the present invention;

[0027] Figure 4 This is a partial cross-sectional view of the oscillation control system of the present invention under non-full load conditions;

[0028] Figure 5 This is a partial cross-sectional view of the anti-roll system of the present invention in the state of ship rolling.

[0029] Figure 6 This is a diagram of the control module of the present invention. Detailed Implementation

[0030] The invention will now be further described with reference to the accompanying drawings.

[0031] like Figures 1 to 5As shown, the present invention includes a liquid tank 1, a liquid level detector 2, a swaying plate 3, a pressure sensor 4, a data processor 5, and hydraulic control rods 6. The liquid tank 1 is a C-shaped liquid tank. The liquid level detector 2 is located on the top of the liquid tank 1 and is fixedly connected to the liquid tank for real-time detection of changes in the liquid level inside the liquid tank. The liquid level detector 2 is preferably a radar-type liquid level detector. Swaying plates 3 are symmetrically arranged on the left and right sides of the liquid tank 1. The swaying plates 3 on both sides are fixed to the liquid tank 1 by multiple hydraulic control rods 6. The hydraulic control rods 6 are magnetorheological hydraulic rods. The four sides of the swaying plate 3 are spaced from the inner wall of the liquid tank 1 to facilitate the adjustment of the position of the swaying plate 3. The pressure sensor 4 is fixedly installed at the end of the hydraulic control rod 6. The cylinders of the hydraulic control rods 6 on the same side are slidably connected to the brackets 7 located inside the liquid tank 1, so that the hydraulic control rods 6 can move within the fixed track of the brackets 7 under the control of the data processor 5. The piston rod in each hydraulic control lever 6 is connected to the sway plate 3 via a universal joint. Driven by multiple hydraulic control levers 6, the sway plate 3 can move back and forth within the liquid tank and can deflect laterally and longitudinally, thereby adjusting the sway plate 3 relative to the liquefied natural gas level in the liquid tank 1. Data processors 5 are symmetrically arranged on both sides of the liquid tank 1. Their input terminals are connected to the output terminals of the level detector 2 and the pressure sensor 4, respectively. The output terminal of the data processor 5 is connected to the control terminal of the hydraulic control lever 6 located on the same side of the liquid tank 1.

[0032] like Figure 2 As shown, the oscillation plate 3 is provided with several horizontal partition plates 32 and vertical partition plates 33, which divide the oscillation plate 3 into several small spaces. Each small space of the oscillation plate 3 has a through hole 31. The through hole 31 is a tapered hole, and the opening direction of the tapered hole is staggered along the vertical direction, such as... Figure 3 As shown. The sway plate 3 can move in the radial direction of the liquid tank 1. Therefore, when the sway plate 3 is impacted by the liquefied natural gas in the liquid tank 1, the hydraulic rod adjusts the hydraulic damping strength to allow the sway plate 3 to reciprocate with the liquid tank 1, absorbing the impact caused by the liquid swaying. According to the data measured by the pressure sensor, the sway plate 3 automatically adjusts its angle to increase the effective swaying area of ​​the sway plate 3.

[0033] The horizontal and vertical baffles on the sway plate 3 can reduce the stress generated by the swaying impact of the sway plate 3 itself, and improve the stability of the sway plate 3. When the liquid tank 1 sways and generates energy, the conical hole can more effectively absorb the energy brought by the liquid impact and release the energy internally. This allows the energy generated by the swaying to be dissipated in time through the sway plate 3 and the hydraulic control rod 6, greatly reducing the damage to the liquid tank components caused by the swaying of the liquid tank and ensuring the safety and stability of the tank.

[0034] like Figure 6As shown, the data processor 5 includes a data receiving module 51, a data processing module 52, and a current control module 53. The input terminal of the data receiving module 51 is connected to the output terminals of the liquid level detector 2 and the pressure sensor 4, respectively. The input terminal of the data processing module 52 is connected to the output terminal of the data receiving module 51. The input terminal of the current control module 53 is connected to the output terminal of the data processing module 52, and the output terminal of the current control module 53 is connected to the control terminal of each hydraulic control lever 6. The data receiving module 51 receives the liquid level height information and liquid surface pressure information sent by the liquid level detector 2 and the pressure sensor 4, respectively, and sends the received liquid level height information and liquid surface pressure information to the data processing module 52. The data processing module 52 calculates the extension and retraction amount of the corresponding hydraulic control lever 6 and the corresponding required current based on the liquid level height information and liquid surface pressure information. The current control module 53 then transmits the required current to the hydraulic control lever 6, thereby realizing the adjustment of the damper plate 3 by the hydraulic control lever 6.

[0035] In use, the data processor 5 first drives the hydraulic control rod 6 to move based on the liquid level height detected by the liquid level detector 2 and the pressure on the swaying plate 3, respectively, so as to adjust the position of the swaying plate 3 and complete the coarse adjustment of the position of the swaying plate 3 in the liquid tank 1. Then, the data processor 5 controls the hydraulic control rod 6 to move again based on the real-time liquid level pressure information detected by the pressure sensor 4, so as to drive the swaying plate 3 to deflect at an angle and complete the fine adjustment of the position of the swaying plate 3 in the liquid tank 1. Finally, the hydraulic damping strength of the hydraulic control rod 6 is adjusted to minimize the safety risks caused by the swaying of the liquid tank.

[0036] The specific oscillation control process is as follows:

[0037] 1) A sway plate that can move left and right relative to the liquid tank is installed in the middle of the liquid tank;

[0038] 2) The liquid level detector detects the liquid level in the tank and adjusts the position of the baffle plate relative to the tank according to the liquid level.

[0039] 3) The pressure sensor detects the pressure value on the surface of the sway plate, and adjusts the extension and retraction of the hydraulic control rod according to the pressure value to control the deflection direction and angle of the sway plate.

[0040] 4) The pressure sensor detects the pressure value on the surface of the damping plate after the damping plate deflects, and adjusts the damping strength of the hydraulic control rod again based on the pressure value;

[0041] 5) Repeat steps 2) to 4) until the height of the liquid level in the tank reaches the minimum value.

[0042] Equipped with a liquid level detector and a pressure sensor, the liquid level and surface pressure in the tank can be detected in real time. This ensures that the sloshing plate can be adjusted in a timely manner according to changes in the liquid level and surface pressure, thus eliminating the sloshing phenomenon in the tank and preventing damage to the tank walls.

[0043] The sloshing plate can control the sloshing of liquefied natural gas in the tank and the operating conditions of the bunkering vessel, and the control methods include:

[0044] When the tank is near full capacity, due to the characteristics of liquefied natural gas, the maximum load capacity of the tank is 90% of its volume, ensuring a certain pressure space. At this time, the data processor controls the extension and retraction of the hydraulic rod to ensure that the extension and retraction are uniform, and the sloshing plate is perpendicular to the surface of the tank. Based on the data measured by the pressure sensor, the damping of the hydraulic control rod is adjusted so that the sloshing plate follows the free surface of the liquefied natural gas in a periodic swaying motion, absorbing most of the impact force on the tank caused by the liquid sloshing, thus achieving the purpose of sloshing control.

[0045] like Figure 4 As shown, when the tank is not fully loaded, the data processor controls the extension and retraction of the hydraulic rod on the corresponding side, so that the sway plate can not only move left and right, but also rotate longitudinally around the central axis within a certain range, increasing the immersion area of ​​the sway plate and maximizing the effective sway control area. The data processor adjusts the damping of the hydraulic rod according to the data measured by the pressure sensor, so that the sway plate follows the free surface of the liquefied natural gas to make periodic swaying, absorbing most of the impact force on the tank caused by the liquid swaying, thus achieving the purpose of sway control.

[0046] like Figure 5 As shown, when an LNG bunkering vessel is in bunkering operation, the vessel is prone to rolling. Based on the liquid level height and liquid pressure data detected by the liquid level detector and pressure sensor, the processor controls the extension and retraction of the hydraulic rod on one side, causing the sway damper to deflect laterally around the central axis within a certain range. This allows the sway damper to simultaneously counteract the swaying caused by the ship's rolling. The damping of the hydraulic control rod is adjusted according to the data measured by the pressure sensor, causing the sway damper to periodically sway with the free surface of the liquefied natural gas, absorbing most of the impact force on the liquid tank caused by the liquid swaying, thus achieving the purpose of sway control.

[0047] To enhance the effectiveness of the LNG tank sloshing control system, the system also includes: a marine GPS locator, a marine electronic inclinometer, a marine weather instrument, a marine depth sounder, and a stress sensor. The outputs of the marine GPS locator, the marine electronic inclinometer, the marine weather instrument, the marine depth sounder, and the stress sensor are all connected to the input of the data processor 5. The data processor 5 can collect information from the marine GPS locator, the marine electronic inclinometer, the marine weather instrument, and the marine depth sounder, and collect real-time stress status information of key nodes in the LNG tank through the stress sensor. Through cloud computing and big data analysis, and by adjusting the sloshing plates according to different conditions such as the characteristics of the loaded liquid, the route path, and sea conditions, it can automatically control the free surface of the LNG tank, minimizing the damage and losses caused by LNG tank sloshing.

Claims

1. A liquid tank oscillation control system for an LNG bunkering vessel, characterized in that, The device includes a liquid tank, in which a liquid level detector and a data processor are fixed. Swaying plates are symmetrically installed on both sides of the liquid tank. The swaying plates on both sides are connected to the liquid tank through multiple connecting devices. Each connecting device has a pressure sensor at its end. The data processor is controlled by the liquid level detector, the pressure sensor, and the connecting devices. The connecting device is a hydraulic control rod. The cylinder of the hydraulic control rod located on the same side of the liquid tank is slidably connected to a bracket installed in the liquid tank on that side. The piston rod in the hydraulic control rod is rotatably connected to the swaying plate.

2. The liquid tank oscillation control system for an LNG bunkering vessel according to claim 1, characterized in that, The oscillation plate is provided with several horizontal and vertical partition plates, which divide the oscillation plate into several small spaces. Each small space of the oscillation plate is provided with a through hole.

3. A liquid tank oscillation control system for an LNG bunkering vessel according to claim 2, characterized in that, The through holes are tapered holes, and the opening directions of the tapered holes are staggered along the vertical direction.

4. The liquid tank oscillation control system for an LNG bunkering vessel according to claim 1, characterized in that, The data processors are symmetrically arranged on both sides of the liquid tank. Their input terminals are connected to the output terminals of the liquid level detector and the pressure sensor, respectively. The output terminal of the data processor is connected to the control terminal of the hydraulic control rod located on the same side of the liquid tank.

5. The sway control process of a liquid tank sway control system for an LNG bunkering vessel according to any one of claims 1 to 4, characterized in that, Includes the following steps: 1) Install the above-mentioned anti-surge system; 2) The liquid level detector detects the liquid level in the tank and adjusts the position of the baffle plate relative to the tank according to the liquid level. 3) The pressure sensor detects the pressure value on the surface of the sway plate, and adjusts the extension and retraction of the hydraulic control rod according to the pressure value, thereby controlling the deflection direction and angle of the sway plate; 4) The pressure sensor detects the pressure value on the surface of the damping plate after the damping plate deflects, and adjusts the damping strength of the hydraulic control rod again based on the pressure value; 5) Repeat steps 2) to 4) until the height of the liquid level in the tank reaches the minimum value.

6. A control method for a liquid tank oscillation control system for an LNG bunkering vessel according to any one of claims 1 to 4, characterized in that, include: When the liquid tank is full, the data processor controls the extension and retraction of the hydraulic control rod on the corresponding side to make the extension and retraction of the hydraulic rod the same. At this time, the sway plate is perpendicular to the surface of the liquid tank. The damping of the hydraulic control rod is adjusted according to the data measured by the pressure sensor, so that the sway plate and the free liquid surface in the liquid tank make periodic swaying. When the liquid tank is not fully loaded, the data processor controls the extension and retraction of the hydraulic control rod on the corresponding side, so that the swaying plate moves while rotating longitudinally around the central axis, increasing the immersion area of ​​the swaying plate. The data processor adjusts the damping of the hydraulic rod according to the data measured by the pressure sensor, so that the swaying plate follows the free liquid surface in the liquid tank to make periodic swaying. When the bunkering vessel is in bunkering operation, the data processor controls the extension and retraction of the hydraulic rod on one side based on the liquid level height and liquid pressure detected by the liquid level detector and pressure sensor, so that the sway plate deflects laterally around the central axis. The damping of the hydraulic control rod is adjusted according to the data measured by the pressure sensor, so that the sway plate follows the free liquid surface in the liquid tank and makes periodic swaying.

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