Device for preventing liquid cargo from being sucked into cargo evaporation gas suction port of marine LNG (Liquefied Natural Gas) transportation tank
By designing an evaporation gas inlet device with a combination of vertical and horizontal baffles in the LNG transport tank, the liquid and gas phases are separated using the principle of fluid dynamics, which solves the problem of liquid LNG entering the evaporation gas processing equipment and achieves reduced energy consumption and cargo loss.
Patent Information
- Application Number
- CN202520607788.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-02
- Publication Date
- 2026-02-10
- Estimated Expiration
- 2035-04-02
AI Technical Summary
During LNG transportation, liquid LNG can easily enter the vapor gas processing equipment through the vapor gas collection pipe, leading to increased energy consumption and equipment damage risk, as well as cargo loss.
A cargo evaporation gas suction device for marine LNG transport tanks is designed, which adopts a combination structure of vertical and horizontal baffles. It uses the principle of fluid dynamics to separate the liquid and gas phases, and the vertical and horizontal baffles form a composite barrier to inhibit droplets from entering the collection pipe.
It effectively reduces energy consumption and equipment damage risk in evaporative gas treatment, reduces liquid loss, and has a simple structure that is easy to manufacture and maintain.
Smart Images
Figure CN223895697U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the technical field of marine LNG transport tank, concretely to a marine LNG transport tank cargo evaporation gas suction port prevents liquid cargo suction device. BACKGROUND
[0002] Marine LNG transport tank refers to the container specially used for transporting liquefied natural gas on the sea, which is usually installed on a liquefied natural gas transport ship (LNG transport ship). The design and manufacture of these transport tanks require extremely high technical level and strict safety standards;
[0003] The cargo evaporation gas suction port (BOG suction port) of the marine LNG transport tank is a key equipment specially used for handling the evaporation gas (BOG) on the LNG ship. The main function of the BOG suction port is to suck the evaporation gas (BOG) generated in the LNG storage tank into the screw compressor for processing;
[0004] At present, a large number of ships begin to use LNG as fuel due to the requirement of IMO specification, which leads to the increase of LNG transport ships. Because of the physical properties of LNG, evaporation gas is inevitable during the transportation process. In order to reduce the cost, an evaporation gas collection pipe is arranged above the liquid tank to collect the evaporation gas for processing and reuse, so as to achieve effective utilization of energy, reduce loss and maximize economic benefit.
[0005] Because the ship sails in the sea, the cargo is stored in the cargo tank and will sway with the ship body. When the evaporation gas is recovered in the evaporation gas collection pipe, the liquid is easy to enter the evaporation gas collection pipe. The suction of the liquid will have two effects: 1. The liquid LNG will affect the processing of the collected gas, which will increase the energy consumption and difficulty of processing the evaporation gas, and there is a risk of damaging the gas processing equipment; 2. The LNG originally in liquid state enters the evaporation gas recovery pipe, resulting in loss of LNG cargo and increase of cost loss.
[0006] At present, the evaporation gas recovery pipeline of the LNG transport ship is only designed by using stainless steel pipe, without considering the problem of liquid LNG sloshing into the evaporation gas recovery pipe, which leads to a large amount of LNG liquid entering the evaporation gas recovery pipe due to sloshing under the condition of full load of the liquid tank.
[0007] Therefore, in view of the above problems, the existing structure and defects are improved, and a marine LNG transport tank cargo evaporation gas suction port liquid cargo suction prevention device is provided. UTILITY MODEL CONTENTS
[0008] The utility model aims at providing a marine LNG transport tank cargo evaporation gas suction port liquid cargo suction prevention device to solve the problems in the above background technology.
[0009] To achieve the above objectives, this utility model provides the following technical solution: a device for preventing liquid cargo from being sucked into the evaporation gas inlet of a marine LNG transport tank, comprising a connecting end, a vertical baffle, and a horizontal baffle. The bottom edge of the connecting end is vertically connected to the vertical baffle, and the horizontal baffle is horizontally connected to the lower end of the vertical baffle near the vertical central axis of the connecting end. The top end of the connecting end is connected to a collection pipe. The connecting end is arranged in a ring structure, and the size of the connecting end is consistent with the specifications of the collection pipe connected to it. Four sets of vertical baffles are arranged in a ring array structure with the connecting end as the circle. The horizontal baffle is located at the end of the vertical baffle away from the connecting end, and the horizontal baffles are welded together in a rectangular cross structure. Moreover, the surface of the horizontal baffle is provided with a dense array of holes at equal intervals for guiding flow.
[0010] Furthermore, the vertical baffle and the horizontal baffle are designed and adjusted according to the specific ship type, and the vertical baffle is usually set with a 30° arc structure.
[0011] Furthermore, the horizontal baffle is typically 50-100mm high, and the horizontal baffle and the vertical baffle are welded together.
[0012] Furthermore, the connecting end, vertical baffle, and horizontal baffle are all made of the same material as the collection pipe, and the collection pipe adopts American standard L. Moreover, the outer surfaces of the connecting end, vertical baffle, and horizontal baffle are all processed by smooth polishing.
[0013] Furthermore, the outer surfaces of the connecting end, the vertical baffle, and the horizontal baffle are all coated with a polytetrafluoroethylene coating, which serves as a liquid-repellent coating. The end of the connecting end away from the vertical baffle is rigidly connected to one end of the collection pipeline using an argon arc welding process.
[0014] Furthermore, the inner wall surface of the connecting end is provided with annular reinforcing ribs to enhance the overall structural rigidity, and the vertical baffle is cut from the collection pipe and vertically welded to the outside of the connecting end.
[0015] Furthermore, the holes on the surface of the horizontal baffle are distributed in a honeycomb structure array, and the edges of the vertical baffle are chamfered and the surface is polished to remove burrs.
[0016] Furthermore, the connecting end, vertical baffle, and horizontal baffle are all connected to each other by welding, and the height difference between the bottom of the connecting end and the top of the horizontal baffle is infinitely adjustable according to the design cargo capacity of the LNG transport tank's liquid cargo compartment.
[0017] This utility model provides a device for preventing liquid cargo from being sucked into the cargo evaporation gas inlet of a marine LNG transport tank, which has the following beneficial effects:
[0018] 1. This utility model incorporates a horizontal baffle welded together with a rectangular cross-shaped structure at the lower end of a vertical baffle. When the liquid cargo tank is not fully loaded, the horizontal baffle is completely exposed to the gas phase space. Due to the significant height difference (greater than 500mm) between the vertical baffle and the inlet, even if the ship is violently rocking, the fluctuation of the liquid surface is limited by the streamlined structure of the base, preventing droplets from being thrown into the suction area of the collection pipe, thus avoiding the intake of liquid cargo. This effectively reduces energy consumption and difficulty in the vapor gas treatment process, reduces the risk of damage to gas treatment equipment, and lowers the cost of liquid cargo transportation. In addition, the entire device has a simple structure and is easy to manufacture, allowing for effective cost control and maintenance, facilitating widespread use.
[0019] 2. This utility model, by providing a honeycomb-shaped flow guide hole structure on the surface of the horizontal baffle, when the liquid cargo tank is nearly full and the horizontal baffle is submerged below the liquid surface, the longitudinal or lateral acceleration of the ship causes the liquid cargo to slosh. After the liquid flow impacts the honeycomb-shaped flow guide hole array of the horizontal baffle, the energy of the liquid surface fluctuation is dissipated due to the principle of fluid dynamics, forming a local turbulent zone. When the ship sways laterally, the liquid cargo surges to the horizontal baffle area due to inertia. The flow guide holes reduce the kinetic energy of the liquid through the diversion effect. At the same time, the composite barrier formed by the vertical baffle and the horizontal baffle forces the liquid flow to generate a reverse vortex, causing the liquid flow to form a counter-vortex at the intersection of the baffles, further dissipating kinetic energy, and finally inhibiting droplets from entering the collection pipe, realizing the effective separation of the liquid and gas phases, and minimizing unnecessary turbulence loss of the liquid cargo. Attached Figure Description
[0020] Figure 1 This is a side view of the main body of the device for preventing liquid cargo from being sucked into the cargo evaporation inlet of a marine LNG transport tank according to the present invention.
[0021] Figure 2 This is a schematic diagram of the main body of a device for preventing liquid cargo from being sucked into the cargo evaporation inlet of a marine LNG transport tank according to the present invention.
[0022] Figure 3 This is a top view of the main body of the device for preventing liquid cargo from being sucked into the cargo evaporation inlet of a marine LNG transport tank according to the present invention.
[0023] Figure 4 This is a perspective structural diagram of the main body of a device for preventing liquid cargo from being sucked into the cargo evaporation inlet of a marine LNG transport tank, according to the present invention.
[0024] In the diagram: 1. Connecting end; 2. Vertical baffle; 3. Horizontal baffle; 4. Collection pipeline. Detailed Implementation
[0025] The embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of this utility model.
[0026] like Figures 1 to 4 As shown, a device for preventing liquid cargo from being sucked into the evaporation gas inlet of a marine LNG transport tank includes a connecting end 1, a vertical baffle 2, and a horizontal baffle 3. The bottom edge of the connecting end 1 is vertically connected to the vertical baffle 2. The horizontal baffle 3 is horizontally connected to the lower end of the vertical baffle 2 near the vertical central axis of the connecting end 1. The top of the connecting end 1 is connected to a collection pipe 4. The connecting end 1 adopts a ring structure, and its size is consistent with the specifications of the collection pipe 4 connected to it. Four sets of vertical baffles 2 are arranged in a ring array with the connecting end 1 as the center. The horizontal baffles 3 are located at the end of the vertical baffles 2 away from the connecting end 1, and the horizontal baffles 3 are welded together in a rectangular cross structure. The surface is equidistantly arrayed with a dense perforated structure for guiding flow. The vertical baffle 2 and the horizontal baffle 3 are designed and adjusted according to the specific ship type. The vertical baffle 2 is usually set with a 30° arc structure, and the vertical height of the horizontal baffle 3 is usually 50-100mm. The horizontal baffle 3 and the vertical baffle 2 are welded together. When the liquid cargo tank is not fully loaded, the horizontal baffle 3 is completely exposed to the gas phase space. Since there is a significant height difference between the vertical baffle 2 and the inlet of the connection end 1, which is greater than 500mm, even if the ship shakes violently, the fluctuation of the liquid surface is limited by the streamlined structure of the base, and the droplets cannot be thrown to the suction port area of the collection pipe 4, thereby avoiding the suction of liquid cargo.
[0027] like Figures 1 to 4As shown, the connecting end 1, vertical baffle 2, and horizontal baffle 3 are all made of the same material as the collecting pipe 4, and the collecting pipe 4 uses American standard 316L stainless steel. The outer surfaces of the connecting end 1, vertical baffle 2, and horizontal baffle 3 are all smoothly polished. The outer surfaces of the connecting end 1, vertical baffle 2, and horizontal baffle 3 are all coated with a polytetrafluoroethylene coating for hydrophobic effects. The end of the connecting end 1 furthest from the vertical baffle 2 is rigidly connected to one end of the collecting pipe 4 using argon arc welding. The inner wall surface of the connecting end 1 has annular reinforcing ribs to enhance the overall structural rigidity. The vertical baffle 2 is cut from the collecting pipe 4 and vertically welded to the outer side of the connecting end 1. The holes on the surface of the horizontal baffle 3 are... The vertical baffle 2 is arranged in a honeycomb structure array. The edges of the vertical baffle 2 are chamfered and the surface is polished to remove burrs. The connecting end 1, the vertical baffle 2, and the horizontal baffle 3 are all welded together. The height difference between the bottom of the connecting end 1 and the top of the horizontal baffle 3 is infinitely adjustable according to the design cargo capacity of the LNG transport tank. When the cargo tank is close to full load, when the horizontal baffle 3 is submerged below the liquid surface, the liquid flow impacts the honeycomb guide hole array holes of the horizontal baffle 3. Due to the principle of fluid dynamics, the energy of the liquid surface fluctuation is dissipated, forming a local turbulent zone. At the same time, the composite barrier formed by the vertical baffle 2 and the horizontal baffle 3 forces the liquid flow to generate a reverse vortex, further dissipating kinetic energy and ultimately inhibiting the droplets from entering the collection pipe.
[0028] In summary, as Figures 1 to 4 As shown, the device for preventing liquid cargo from being sucked into the cargo evaporation inlet of the LNG transport tank is used as follows: First, the vertical baffle 2 is cut and vertically welded to the outside of the connecting end 1 using the collection pipe 4. At the same time, the horizontal baffle 3 is welded to the lower end of the vertical baffle 2 using a rectangular cross structure. Then, the connecting end 1 and the collection pipe 4 are welded together. During this process, the height difference between the bottom of the connecting end 1 and the top of the horizontal baffle 3 can be steplessly adjusted according to the design cargo capacity of the LNG transport tank's liquid cargo compartment and set to be greater than 500mm.
[0029] When the liquid cargo tank is not fully loaded, the horizontal baffle 3 is completely exposed to the gas phase space. Due to the significant height difference (Δh≥500mm) between the vertical baffle 2 and the inlet of the collection pipe 4, even if the ship is violently rocking, the fluctuation of the liquid surface is limited by the streamlined structure of the base, and the droplets cannot be thrown to the suction area of the collection pipe 4, thus avoiding the inhalation of liquid cargo.
[0030] When the cargo tank is nearly full, the horizontal baffle 3 is submerged below the liquid surface. The longitudinal or lateral acceleration of the ship causes the cargo to slosh. After the liquid flow impacts the honeycomb-shaped guide hole array of the horizontal baffle 3, the energy of the liquid surface fluctuation is dissipated due to the principle of fluid dynamics, forming a local turbulent zone. When the ship sloshes laterally, the cargo surges to the area of the horizontal baffle 3 due to inertia. The guide holes reduce the kinetic energy of the liquid through the diversion effect. At the same time, the composite barrier formed by the vertical baffle 2 and the horizontal baffle 3 forces the liquid flow to generate a reverse vortex, so that the liquid flow forms a counter-vortex at the intersection of the baffles, further dissipating kinetic energy and ultimately preventing droplets from entering the collection pipe, thus achieving effective separation of the liquid and gas phases.
[0031] The embodiments of this utility model are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the utility model to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical applications of this utility model, and to enable those skilled in the art to understand this utility model and design various embodiments with various modifications suitable for a particular purpose.
Claims
1. A device for preventing liquid cargo from being sucked into the evaporation gas inlet of a marine LNG transport tank, comprising a connecting end (1), a vertical baffle (2), and a horizontal baffle (3), characterized in that: The bottom edge of the connecting end (1) is vertically connected to a vertical baffle (2). The horizontal baffle (3) is horizontally connected to the lower end of the vertical baffle (2) near the vertical central axis of the connecting end (1). The top of the connecting end (1) is connected to a collection pipe (4). The connecting end (1) is set in a ring structure. The size of the connecting end (1) is the same as that of the collection pipe (4) connected to it. The vertical baffle (2) is set in four groups and arranged in a ring array structure with the connecting end (1) as the circle. The horizontal baffle (3) is set at the end of the vertical baffle (2) away from the connecting end (1). The horizontal baffle (3) is welded together with a rectangular cross structure. The surface of the horizontal baffle (3) is equidistantly arrayed with a dense hole structure for use as a guide hole.
2. The device for preventing liquid cargo from being sucked into the cargo evaporation inlet of a marine LNG transport tank according to claim 1, characterized in that, The vertical baffle (2) and the horizontal baffle (3) are designed and adjusted according to the specific ship type, and the vertical baffle (2) is set with a 30° arc structure.
3. The device for preventing liquid cargo from being sucked into the cargo evaporation inlet of a marine LNG transport tank according to claim 1, characterized in that, The horizontal baffle (3) has a vertical height of 50-100mm, and the horizontal baffle (3) and the vertical baffle (2) are welded together.
4. The device for preventing liquid cargo from being sucked into the cargo evaporation inlet of a marine LNG transport tank according to claim 1, characterized in that, The connecting end (1), vertical baffle (2) and horizontal baffle (3) are all made of the same material as the collection pipe (4), and the collection pipe (4) is made of American standard 316L. Moreover, the outer surfaces of the connecting end (1), vertical baffle (2) and horizontal baffle (3) are all processed by smooth grinding.
5. A device for preventing liquid cargo from being sucked into the cargo evaporation inlet of a marine LNG transport tank according to claim 1, characterized in that, The outer surfaces of the connecting end (1), the vertical baffle (2) and the horizontal baffle (3) are all coated with a polytetrafluoroethylene coating and used as a liquid-repellent coating. The end of the connecting end (1) away from the vertical baffle (2) is rigidly connected to the end of the collection pipe (4) by argon arc welding.
6. A device for preventing liquid cargo from being sucked into the cargo evaporation inlet of a marine LNG transport tank according to claim 1, characterized in that, The inner wall surface of the connecting end (1) is provided with annular reinforcing ribs to enhance the overall structural rigidity. The vertical baffle (2) is cut using a collection pipe (4) and vertically welded to the outside of the connecting end (1).
7. A device for preventing liquid cargo from being sucked into the cargo evaporation inlet of a marine LNG transport tank according to claim 1, characterized in that, The holes on the surface of the horizontal baffle (3) are arranged in a honeycomb structure array, and the edges of the vertical baffle (2) are chamfered and the surface is polished to remove burrs.
8. A device for preventing liquid cargo from being sucked into the cargo evaporation inlet of a marine LNG transport tank according to claim 1, characterized in that, The connecting end (1), vertical baffle (2), and horizontal baffle (3) are all connected by welding to each other, and the height difference between the bottom of the connecting end (1) and the top of the horizontal baffle (3) is infinitely adjustable according to the design cargo capacity of the LNG transport tank's liquid cargo compartment.