LNG (Liquefied Natural Gas) fuel tank pry for trailing suction dredger
By integrating LNG storage and gas supply equipment on the rake suction dredger, safety hazards caused by dispersed layout are solved, and high integration and safety improvements are achieved.
Patent Information
- Application Number
- CN202422224370.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-11
- Publication Date
- 2025-07-04
- Estimated Expiration
- 2034-09-11
AI Technical Summary
The existing LNG fuel supply system is arranged and dispersed on the rake-sucking dredger, and the flammable and explosive gases pose danger to the hull and affect ship safety.
It integrates LNG storage and gas supply functional components, is centrally arranged in the TCS room, including a gas buffer tank, an LNG fuel pump, an LNG vaporizer and a BOG heater, and uses negative pressure ventilation and airtight door isolation to reduce dangerous gas diffusion.
It improves the integration of gas equipment, shortens the monitoring and construction cycle, reduces dangerous areas, and enhances ship operation safety.
Smart Images
Figure CN223063650U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a rake suction dredger LNG fuel tank skid. Background Technique
[0002] In recent years, as China has continuously put forward higher requirements for the low-carbon environmental protection standards of the shipping industry, the attention to the upgrading and transformation of the latest generation of green and energy-saving ship types and the existing technologies of the fleet has been increasing day by day. LNG fuel has been widely used globally and is widely recognized as the preferred large-scale clean alternative fuel. At present, it has been widely applied to ship types such as passenger ships, cruise ships, LNG carriers, oil tankers, and container ships.
[0003] The LNG (liquefied natural gas) fuel supply system mainly consists of systems such as an LNG fuel storage system, an LNG fuel supply system, an LNG filling system, and a water glycol system. The main components of the existing LNG fuel supply system are arranged relatively dispersedly and not concentrated. The main component of LNG is methane, which is a flammable and explosive gas. An accident of a certain component is likely to cause great danger to the hull. Therefore, a rake suction dredger LNG fuel tank skid is proposed for the above problems. Content of the Utility Model
[0004] The purpose of the utility model is to provide a rake suction dredger LNG fuel tank skid to overcome the existing defects, integrating the functional components of LNG storage and gas supply, and reducing the impact of dangerous gases on the safe areas of the whole ship.
[0005] The technical solution to achieve the above purpose is: a rake suction dredger LNG fuel tank skid, including an LNG storage tank, an air lock room, a bolted hatch room, and a TCS room (fuel ship connection location);
[0006] The TCS room is arranged at the upper end of the LNG storage tank, the bolted hatch room is arranged at the opening of the TCS room, and the air lock room is arranged at the opening of the bolted hatch room;
[0007] One gas buffer tank, two LNG fuel pumps, two LNG vaporizers, and two BOG heaters are arranged in the TCS room.
[0008] Preferably, the suction ports of the two LNG fuel pumps extend into the LNG storage tank, and the upper ends are jointly connected to the LNG gas supply pipe. The other end of the LNG gas supply pipe is connected in parallel to the two LNG vaporizers. The other ends of the two LNG vaporizers are jointly connected to the gas buffer tank, and the other end of the gas buffer tank is connected in parallel to the left main engine interface, the right main engine interface, the generator interface, and the boiler interface.
[0009] Preferably, the LNG filling pipe is located within the TCS compartment. One end of the LNG filling pipe is connected to the TCS source outside the TCS compartment, and the other end is connected to the inside of the LNG storage tank.
[0010] Preferably, the NG return pipe is located within the TCS compartment. One end of the NG return pipe is connected to the NG exhaust port outside the TCS compartment, and the other end is connected to the LNG storage tank; the middle of the NG return pipe is connected in parallel to two BOG heaters through an extension pipe, and the other ends of the two BOG heaters are connected to the generator interface and the boiler interface.
[0011] Preferably, a breather pipe is connected to the LNG storage tank.
[0012] Preferably, the end of the LNG filling pipe located inside the LNG storage tank is connected with a top spray head.
[0013] Preferably, the air lock compartment, the bolted hatch compartment, and the TCS compartment are all under negative pressure ventilation.
[0014] Preferably, the surface of the LNG storage tank is sprayed with polyurethane.
[0015] The beneficial effects of the present utility model are as follows: For the LNG fuel tank skid of this trailing suction hopper dredger, by arranging a TCS compartment at the upper end of the LNG storage tank, a bolted hatch compartment at the opening of the TCS compartment, and an air lock compartment at the opening of the bolted hatch compartment; there is a gas buffer tank, two LNG fuel pumps, two LNG vaporizers, and two BOG heaters arranged inside the TCS compartment. All gas supply equipment is concentrated and arranged inside the TCS compartment, with a high degree of integration, which is beneficial to shortening the shipbuilding supervision cycle; at the same time, the gas equipment is mainly integrated inside the TCS compartment, which also reduces the gas hazardous area and is beneficial to the safety of ship operation. Description of the Drawings
[0016] Figure 1 is a detailed view of the positions of the air lock compartment and the bolted hatch compartment of the present utility model;
[0017] Figure 2 is a detailed view of the inside of the TCS compartment of the present utility model;
[0018] Figure 3 is a detailed view of the pipeline connection of the TCS compartment of the present utility model.
[0019] In the figure: 1. LNG storage tank; 2. Airlock room; 3. Bolt hatch room; 4. TCS room; 5. Gas buffer tank; 6. LNG fuel pump; 7. LNG vaporizer; 8. BOG heater; 9. LNG supply pipe; 10. Left main engine interface; 11. Right main engine interface; 12. Generator interface; 13. Boiler interface; 14. TCS source; 15. Top spray head; 16. NG return pipe; 17. NG exhaust port; 18. Vent pipe; 19. LNG filling pipe. Detailed implementation manners
[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. In the description of the present utility model, it should be noted that the orientation or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings. These are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.
[0021] The present utility model will be further described below with reference to the accompanying drawings.
[0022] As Figures 1-3 shown, a trailing suction hopper dredger LNG fuel tank skid includes an LNG storage tank 1, an airlock room 2, a bolt hatch room 3, and a TCS room 4; a TCS room 4 is arranged at the upper end of the LNG storage tank 1, a bolt hatch room 3 is arranged at the opening of the TCS room 4, and an airlock room 2 is arranged at the opening of the bolt hatch room 3; the airlock room 2, the bolt hatch room 3, and the TCS room 4 are all negatively pressured for ventilation. The surface of the LNG storage tank 1 is sprayed with polyurethane.
[0023] Specifically, an independent C-type catamaran tank integrated with TCS is used to form an LNG fuel tank skid, which serves as an independent gas supply unit with the functions of LNG storage and gas supply. The impact of dangerous gases on the safe areas of the whole ship is reduced. At the same time, the highly integrated gas supply system also greatly shortens the project supervision period.
[0024] Specifically, the LNG storage tank 1 adopts a double-body independent C-type tank, with a spherical head and no gas chamber design. The tank body is made of EN10028-4, X7Ni9, which can meet the requirements of LNG ultra-low temperature storage and BOG pressure maintenance; the volume meets the consumption of the ship's 10-day continuous operation and the remaining 5% of LNG is used for cold insulation. Calculate the volume of the LNG fuel tank as:
[0025] V = (24 * Q * d) / (ρ * LL * 95%)
[0026] Wherein: V is the calculated volume of the fuel tank, which is 1482 m3
[0027] Q is the gas consumption under the main engine operating conditions, which is 2091 kg / h
[0028] d is the number of consecutive operating days, which is 10 d
[0029] ρ is the density of LNG: 420 kg / m3
[0030] LL is the loading limit: 84.83%
[0031] According to the above calculations and the external shape design of the LNG fuel tank, the volume of the LNG fuel tank is rounded up to 1550 m3. The temperature of LNG under normal pressure is -162 °C. In order to reduce the heat intrusion into the fuel tank, the fuel tank is sprayed with 330 mm of polyurethane.
[0032] Specifically, three-point temperature sensors are equipped on the surfaces of the left and right tanks of the LNG storage tank 1 to monitor the surface temperature of the tank.
[0033] Specifically, two radar level sensors are installed on the top of the left and right tanks of the LNG storage tank 1 to monitor the liquid level of the LNG storage tank 1, and high and low level alarms are set for the level gauge for alarm. When the low liquid level alarm in the tank is triggered, to prevent cavitation damage to the fuel pump, the LNG fuel pump 6 will be cut off.
[0034] Specifically, a set of three-point temperature sensors are configured inside the left and right tanks of the LNG storage tank 1 to monitor the temperature at different heights inside the LNG tank. When the LNG fuel tank is filled with LNG and remains stationary for a long time, temperature stratification will occur inside the tank, and the temperature of the LNG at the bottom layer will be lower than that at the top layer. If the LNG at the bottom and top layers suddenly mixes, a large amount of BOG will be generated, leading to overpressure in the fuel tank. When temperature stratification is detected, the spray valve can be opened to spray low-temperature LNG into the upper layer of the LNG tank to make the temperature of the upper and lower layers uniform. All pipeline interfaces and equipment installation interfaces of the LNG storage tank 1 are arranged in the TCS room 4 to prevent any dangerous gas from leaking into the safe area.
[0035] Specifically, to enter the TCS room 4 from the safe area, it is necessary to pass through the air lock room 2 and the bolted hatch room 3 in sequence. The structures of the air lock room 2, the bolted hatch room 3 and the TCS room 4 are made of SS316L and are hermetically welded to the surface of the LNG storage tank 1. The air lock room 2 and the external environment, as well as the air lock room 2 and the bolted hatch room 3, are isolated by airtight doors. The airtight doors are equipped with photoelectric position switches to monitor the status of the airtight doors. The two airtight doors cannot be opened simultaneously; the bolted hatch room and the TCS are isolated by an airtight bolted hatch, and the hatch is equipped with a photoelectric position switch.
[0036] Specifically, to prevent the leakage of dangerous gases into the safe area, the airlock room 2, the bolted hatch room 3, and the TCS room 4 are all equipped with negative pressure ventilation. The designed ventilation pressure of the airlock room 2 is slightly higher than that of the bolted hatch room, and the designed ventilation pressure of the bolted hatch room is slightly higher than that of the TCS room 4, so as to ensure that the dangerous gases that may exist in the TCS room 4 do not spread to the safe area. Thus, the dangerous area is isolated within the TCS room 4. The outside of the TCS room 4 is the safe area.
[0037] Specifically, a liquid accumulation pan is formed between the bulkhead of the TCS room 4 and the upper surface of the LNG storage tank 1, and a liquid level switch and a temperature sensor are equipped on each side, which are used to monitor the LNG leakage situation. The signals of the liquid level switch and the temperature sensor will trigger the control system alarm and cut off the gas supply.
[0038] Specifically, all the pipeline systems from the bulkhead of the TCS room 4 passing through to the natural gas pipelines in the safe area adopt double-wall pipes, and vacuum double-wall pipes or ventilated double-wall pipes are used according to the designed temperature of the pipelines.
[0039] Specifically, a gas buffer tank 5, two LNG fuel pumps 6, two LNG vaporizers 7, and two BOG heaters 8 are arranged in the TCS room 4.
[0040] Specifically, the suction ports of the two LNG fuel pumps 6 extend into the LNG storage tank 1, and the upper ends are jointly connected to the LNG gas supply pipe 9. The other end of the LNG gas supply pipe 9 is connected in parallel to the two LNG vaporizers 7. The other ends of the two LNG vaporizers 7 are jointly connected to the gas buffer tank 5, and the other end of the gas buffer tank 5 is connected in parallel to the left main engine interface 10, the right main engine interface 11, the generator interface 12, and the boiler interface 13.
[0041] Specifically, the LNG filling pipe 19 is located in the TCS room 4. One end of the LNG filling pipe 19 is connected to the TCS source 14 outside the TCS room 4, and the other end is connected to the inside of the LNG storage tank 1. One end of the LNG filling pipe 19 located inside the LNG storage tank 1 is connected with a top spray head 15.
[0042] Specifically, the NG return pipe 16 is located in the TCS room 4. One end of the NG return pipe 16 is connected to the NG exhaust port 17 outside the TCS room 4, and the other end is connected to the LNG storage tank 1; the middle part of the NG return pipe 16 is connected in parallel to the two BOG heaters 8 through an extension pipe, and the other ends of the two BOG heaters 8 are connected to the generator interface 12 and the boiler interface 13.
[0043] Specifically, a breather pipe 18 is connected to the LNG storage tank 1.
[0044] Specifically, the required gas supply temperature for the left main engine interface 10, right main engine interface 11, generator interface 12, and boiler interface 13 is 0 - 60°C, and the gas supply pressure for the left main engine interface 10, right main engine interface 11, and generator interface 12 is 6 - 10 barg, while the gas supply pressure for the boiler interface 13 is 2 barg. To meet the gas supply pressure requirements, the LNG is pressurized to 8 barg by the LNG fuel pump 6, vaporized into gas at 30°C by the LNG vaporizer 7, and supplied to each gas user through the gas buffer tank 5 and the main valve. When the pressure of the LNG fuel tank 5 reaches 3 barg, the low-temperature gaseous natural gas will flow through the BOG heater 8 under pressure and be supplied to the hot water heater through the main valve for consumption to maintain the pressure of the LNG fuel tank.
[0045] Specifically, two deep-well type LNG fuel pumps 6 are installed on the LNG fuel tank 1. The fuel pump body is located in the liquid accumulation well at the inner bottom of the LNG fuel tank, and the motor is located in the TCS outside the tank, which can reduce the influence of motor heat on LNG evaporation. The designed flow rate of the fuel pump is 9.5 m3, and one fuel pump can provide LNG for all gas under full load conditions. A liquid accumulation well is set at the bottom of the fuel pump, and the suction port of the fuel pump is placed inside the liquid accumulation well to reduce the influence of the net positive suction head on the fuel pump.
[0046] Specifically, two LNG fuel vaporizers 7 are configured inside the TCS room 4, one in use and one in reserve. According to the compact space of the TCS room 4, plate-shell type vaporizers are used. The heat exchange plates are welded to reduce the risk of LNG leakage. The heating medium uses water glycol for heating, which can directly vaporize LNG from -162°C to 30°C. A low-temperature sensor and a flow meter are set at the water glycol outlet of the vaporizer. When an alarm occurs in the system, the LNG supply can be cut off to prevent the water glycol from freezing.
[0047] Specifically, one gas buffer tank 5 is configured inside the TCS room 4 to eliminate the adverse impact on the gas supply pressure when the main engine load changes and maintain the stability of the gas supply pressure. A gas main valve is designed at the outlet of the gas buffer tank 5. In case of an emergency, the gas main valve can be cut off separately to stop the gas supply. A pressure sensor is set on the gas buffer tank 5 to monitor the gas pressure in the buffer tank and control the rotation speed of the fuel pump. A temperature sensor is also set at the outlet of the buffer tank to prevent low-temperature gas from entering the gas user under any circumstances.
[0048] Specifically, the LNG vaporizer 7 and the fuel buffer tank 5 are arranged inside the TCS room 4 and supply gas to the gas users through the main valve. In an emergency, the main valve can be cut off to stop supplying gas outside, limiting the dangerous area to the minimum and having higher safety.
[0049] Specifically, based on the requirements of the gas hot water heater and the gas supply pressure and temperature of the gas auxiliary generator, combined with the internal dimensions of the TCS room 4. The BOG heater 8 adopts a plate-shell heat exchanger, the heat exchange plates are welded, and the heating medium is water glycol to prevent the heater from freezing and scaling. After the BOG pressure in the LNG fuel tank 1 rises to 3 barg, the valve at the inlet of the BOG heater 8 can be opened. The low-temperature BOG is heated from -163 °C to 30 °C by the BOG heater 8 and then directly supplies gas to the auxiliary generator or the hot water heater through the main valve, thereby reducing the fuel tank pressure. Without the need for a compressor, the required BOG can be provided to the auxiliary generator and the hot water heater only through the cabin pressure. An independent gas main valve is provided at the rear of the heater, and the main valve can be cut off in case of an emergency to minimize the restricted dangerous area.
[0050] For this LNG fuel tank skid of the trailing suction hopper dredger, a TCS room is arranged at the upper end of the LNG storage tank, a bolted hatch room is arranged at the opening of the TCS room, and an air lock room is arranged at the opening of the bolted hatch room; a gas buffer tank, two LNG fuel pumps, two LNG vaporizers and two BOG heaters are arranged in the TCS room. All gas supply equipment is centrally arranged inside the TCS room, with a high degree of integration, which is conducive to shortening the shipbuilding supervision cycle; at the same time, the gas equipment is mainly integrated inside the TCS room, which also reduces the gas dangerous area and is conducive to the safety of ship operation.
[0051] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A LNG fuel tank skid for a trailing suction hopper dredger, characterized in that, It includes an LNG storage tank (1), an air lock chamber (2), a bolted hatch chamber (3) and a TCS chamber (4); The TCS chamber (4) is arranged at the upper end of the LNG storage tank (1), the bolted hatch chamber (3) is arranged at the opening of the TCS chamber (4), and the air lock chamber (2) is arranged at the opening of the bolted hatch chamber (3); There is a gas buffer tank (5), two LNG fuel pumps (6), two LNG vaporizers (7) and two BOG heaters (8) arranged in the TCS chamber (4).
2. The LNG fuel tank skid of the trailing suction hopper dredger according to claim 1, wherein The suction ports of the two LNG fuel pumps (6) extend into the LNG storage tank (1), and are jointly connected to the LNG supply pipe (9) at the upper end. The other end of the LNG supply pipe (9) is connected to the two LNG vaporizers (7) in parallel. The other ends of the two LNG vaporizers (7) are jointly connected to the gas buffer tank (5), and the other end of the gas buffer tank (5) is connected to the left main engine interface (10), the right main engine interface (11), the generator interface (12) and the boiler interface (13) in parallel.
3. The LNG fuel tank skid of the trailing suction hopper dredger according to claim 1, characterized in that, The LNG filling pipe (19) is located in the TCS chamber (4). One end of the LNG filling pipe (19) is connected to the TCS source (14) outside the TCS chamber (4), and the other end is connected to the inside of the LNG storage tank (1).
4. The LNG fuel tank skid of the trailing suction hopper dredger according to claim 2, wherein The NG return pipe (16) is located in the TCS chamber (4). One end of the NG return pipe (16) is connected to the NG exhaust port (17) outside the TCS chamber (4), and the other end is connected to the LNG storage tank (1); the middle of the NG return pipe (16) is connected to the two BOG heaters (8) in parallel through an extension pipe, and the other ends of the two BOG heaters (8) are connected to the generator interface (12) and the boiler interface (13).
5. The LNG fuel tank skid of the trailing suction hopper dredger according to claim 1, characterized in that, A breather pipe (18) is connected to the LNG storage tank (1).
6. The LNG fuel tank skid of the trailing suction hopper dredger according to claim 3, characterized in that One end of the LNG filling pipe (19) located inside the LNG storage tank (1) is connected with a top spray head (15).
7. The LNG fuel tank skid of the trailing suction hopper dredger according to claim 1, characterized in that, The air lock chamber (2), the bolted hatch chamber (3) and the TCS chamber (4) are all negatively pressurized for ventilation.
8. The LNG fuel tank skid of the trailing suction hopper dredger according to claim 1, wherein The surface of the LNG storage tank (1) is sprayed with polyurethane.