A methanol fuel pressure balancing system

Abstract

The present application relates to a kind of methanol fuel pressure balance systems, including methanol fuel daily cabin, Tesla valve, pressure balance pipeline, methanol fuel storage cabin, methanol fuel storage cabin is connected between methanol fuel daily cabin by independent pressure balance pipeline and Tesla valve, not with the common pipeline of the gas pipe of methanol fuel storage cabin and methanol fuel daily cabin.The present application relative to prior art, mainly solve the problem of how to design pressure balance pipe when methanol fuel storage cabin and methanol fuel daily cabin of large ship are far away, reduce the pollution of methanol vapor to environment, reduce nitrogen consumption, utilize the special structure of Tesla valve, so that system is simple and reliable, can adapt to different arrangement scheme and different environmental conditions.

Description

Technical Field

[0001] This invention relates to a methanol fuel pressure balancing system, belonging to the field of ship design and manufacturing technology. Background Technology

[0002] Ships using methanol fuel typically employ closed-loop systems for both the methanol transport and supply systems, taking into account the toxicity of methanol to humans. Methanol is transported from the methanol fuel storage tank to the methanol fuel day tank. As the liquid level in the methanol day tank rises, the pressure inside the tank increases due to the nitrogen-sealed pressure system. This pressure needs to be released in a suitable manner to maintain the pressure in the methanol fuel day tank at the set value.

[0003] There are two main ways to release pressure from the methanol fuel day tank. One way is to release the pressure into the atmosphere through the PV (pressure / vacuum) valve of the methanol fuel day tank. This method will pollute the atmospheric environment and increase nitrogen consumption. The other way is to use a pressure balancing pipeline to connect the methanol fuel day tank and the methanol fuel storage tank, and transfer the nitrogen sealed in the methanol fuel day tank to the methanol fuel storage tank.

[0004] When the methanol fuel storage tank and the methanol fuel day use tank are located in the same hazardous area, a pressure balance pipeline can be used to connect the two tanks. When the methanol fuel transfer pump transfers methanol fuel from the storage tank to the day use tank, the pressurized nitrogen in the methanol fuel day use tank will return to the methanol fuel storage tank through this pressure balance pipeline, ensuring the pressure balance of the entire closed methanol fuel system.

[0005] When the methanol fuel storage tank and the methanol fuel day tank are located in different hazardous areas and are relatively far apart, the pressure balancing pipeline connecting the methanol fuel storage tank and the methanol fuel day tank faces the following problems: ① When the pressure balancing pipeline passes through a safe and enclosed space, a double-walled pipe is required. Double-walled pipes are expensive, and ventilation of the double-walled pipe needs to be considered, increasing construction costs; ② The methanol fuel day tank is located in the fuel preparation room at the stern of the ship, while the methanol fuel storage tank is located in the middle of the ship. Methanol vapor in the pressure balancing pipeline condenses into methanol liquid at low ambient temperatures. Considering the stern tilt of the ship, the methanol liquid will reduce the flow area of ​​the pressure balancing pipeline, thereby reducing the pressure balancing effect of the pipeline; ③ When a fire occurs on one side of the methanol fuel storage tank, the accident may spread to the methanol fuel day tank through the pressure balancing pipeline, and vice versa.

[0006] The invention patent "A replenishment system for methanol dual-fuel ship day tanks and its usage method (authorization announcement number CN 113291446 B, 2022.04.19)" applied for by Huang Youhua et al. of Guangzhou Shipyard International Co., Ltd. directly connects the high-speed venting valve pipeline on the methanol fuel storage tank and the methanol fuel day tank, which cannot meet the requirement of the classification society's specifications that each methanol fuel tank should be equipped with an independent venting system. Meanwhile, the pipeline uses short connecting pipes for intermittent connection, failing to consider the need for continuous transfer of methanol from the methanol storage tank to the methanol day tank under normal ship operating conditions, and also failing to meet the pressure balance requirements of the methanol storage tank and the methanol day tank under non-transfer conditions. Therefore, it is greatly limited in actual use and requires comprehensive consideration of the existing problems. When the connecting pipe is not connected, if the pressure in the methanol fuel day tank increases, the PV (pressure / vacuum) valve will open, and methanol vapor and sealing nitrogen will be directly discharged into the atmosphere in the form of a mixture, which is neither economical nor environmentally friendly. The patent does not consider the condensation of methanol vapor in the connecting pipe under low-temperature operating conditions, and a large amount of condensed methanol liquid will render the connecting pipe ineffective.

[0007] The invention patent "Arrangement of Methanol Fuel Containment and Supply System for Dual-Fuel Large Container Ships" applied for by Lin Jie et al. of Shanghai Ship Research and Design Institute (Application Publication No. CN 115158539 A, 2022.10.11) mainly focuses on the arrangement of methanol fuel storage tanks, methanol fuel day tanks, high-speed vent valves, etc., but does not address the pressure balance issue between methanol fuel storage tanks and methanol fuel day tanks.

[0008] The invention patent "Marine Methanol Fuel Supply Method (CN114320686 B, 2023.04.28)" applied for by Qian Zhenghua et al. of the 711 Research Institute of China Shipbuilding Group Co., Ltd. mainly describes a method for supplying methanol fuel to ships. Through a methanol recovery unit, methanol fuel that is not used by the methanol engine is returned to the methanol storage tank to realize the recovery and use of methanol fuel. However, it does not address the pressure balance issue between the methanol fuel storage tank and the methanol fuel day tank.

[0009] None of the aforementioned patents can solve the problem of how to design the pressure balancing pipe when the methanol fuel storage tank and the methanol fuel day tank of a large ship are far apart, so as to improve the safety of the methanol fuel system.

[0010] For large ships where the methanol fuel storage tank and the methanol fuel day-use tank are far apart, the existing technology has the following drawbacks: ① If conventional pipelines are used to connect the methanol fuel storage tank and the methanol fuel day-use tank on large ships, it is easy for methanol fuel to overflow into each other, causing chaos in the methanol fuel tank pressure control system, triggering false alarms, and causing trouble for crew management; ② The methanol fuel system does not have a pressure balancing pipe between the methanol fuel storage tank and the methanol fuel day-use tank, which means that nitrogen needs to be added frequently when the fuel in the methanol fuel storage tank is low, increasing the consumption of sealing nitrogen; while the methanol fuel day-use tank becomes overpressurized due to the injection of methanol, and the PV (pressure / vacuum) valve needs to be opened intermittently. The released methanol vapor and nitrogen mixture not only pollutes the air, but also affects the surrounding personnel. ① It can cause toxic damage, and the accumulation of methanol vapor can also create an explosion hazard; ② Because the methanol fuel storage tank and the methanol fuel day tank of large ships are far apart, double-walled pipes are required when the pressure balancing pipe passes through a safe location. Double-walled pipes are expensive, and ventilation of the double-walled pipes needs to be considered, which increases construction costs; ③ Methanol fuel day tanks are usually located in the fuel preparation room near the engine room at the stern of the ship, while methanol fuel storage tanks are located in the middle of the ship. Methanol vapor in the pressure balancing pipe condenses into methanol liquid when the ambient temperature is low. Considering the stern tilt of the ship, the methanol liquid will reduce the effective flow area of ​​the pressure balancing pipe, thereby reducing the pressure balancing effect of the pipe; ④ When a fire occurs on one side of the methanol fuel storage tank, the accident may spread to the methanol fuel day tank through the pressure balancing pipe, and vice versa.

[0011] To address the aforementioned problems with methanol fuel systems, it is necessary to adopt special design solutions based on the characteristics of methanol fuel systems and the layout of methanol fuel tanks on large ships, to solve these problems one by one. At the same time, the economic efficiency of construction and the convenience of crew maintenance should be considered to make the system design more reasonable and improve the safety of methanol fuel systems. Summary of the Invention

[0012] The present invention aims to solve the problems existing in the prior art by proposing a methanol fuel pressure balancing system.

[0013] To achieve the above objectives, the technical solution of the present invention is: a methanol fuel pressure balancing system, comprising a methanol fuel day use tank, a Tesla valve, a pressure balancing pipeline, and a methanol fuel storage tank. The methanol fuel storage tank and the methanol fuel day use tank are connected by an independent pressure balancing pipeline and a Tesla valve, and do not share pipelines with the vent pipes of the methanol fuel storage tank and the methanol fuel day use tank.

[0014] Furthermore, the methanol fuel storage tank and the methanol fuel day tank are far apart. The methanol fuel storage tank is located below the superstructure in the middle of the ship, while the methanol fuel day tank is located near the engine room at the stern of the ship.

[0015] Furthermore, the Tesla valves of the methanol fuel storage tank and the methanol fuel day tank are connected by a pressure balancing pipeline.

[0016] Furthermore, the methanol fuel storage tank and the methanol fuel day use tank are connected by a methanol fuel transfer pipeline and a methanol fuel transfer pump.

[0017] Furthermore, the Tesla valve has a one-way conduction characteristic, allowing the methanol vapor and nitrogen mixture to pass through the Tesla valve to achieve pressure balance, while methanol liquid cannot pass through the Tesla valve. When the methanol fuel transfer pump transfers methanol to the methanol fuel day tank through the methanol fuel transfer pipeline, no methanol liquid will overflow into the pressure balance pipeline.

[0018] Furthermore, a venting pipeline is installed at the lowest point of the pressure balancing pipeline, and a venting pipeline control valve and a liquid level alarm device are installed on the venting pipeline.

[0019] Furthermore, when methanol is present in the pressure balancing pipeline, the alarm signal from the liquid level alarm device is transmitted to the ship's monitoring and alarm system, reminding the crew to open the release control valve.

[0020] Furthermore, under low-temperature operating conditions, methanol vapor condenses and is discharged into the discharge collection chamber through the discharge pipeline.

[0021] Furthermore, at the outlet of the Tesla valve of the methanol fuel daily use compartment, a nitrogen gas supply from a nitrogen tank is connected via a nitrogen control valve to purge the methanol liquid remaining in the pressure balance pipeline.

[0022] Furthermore, the pressure balancing pipeline is arranged above the main deck, using a single-walled pipe, and carries a mixture of methanol vapor and nitrogen gas.

[0023] The beneficial effects of this invention are:

[0024] Compared with the prior art, the present invention mainly solves the problem of how to design the pressure balance pipe when the methanol fuel storage tank and the methanol fuel day tank of large ships are far apart. It reduces the pollution of methanol vapor to the environment, reduces nitrogen consumption, and utilizes the special structure of Tesla valve to make the system simple and reliable, and can adapt to different layout schemes and different environmental conditions. These are all technical effects directly brought about by the technical features. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the methanol fuel pressure balance system described in the embodiment;

[0026] Figure 2 This is a cross-sectional overview of a Tesla valve.

[0027] In the diagram: 1-Methanol fuel daily use compartment; 201-First Tesla valve; 202-Second Tesla valve; 3-Nitrogen tank; 4-Nitrogen control valve; 5-Release pipeline; 6-Release pipeline control valve; 7-Release collection compartment; 8-Pressure balancing pipeline; 9-Methanol fuel storage compartment; 10-Liquid level alarm device; 11-Methanol fuel transfer pipeline; 12-Methanol fuel transfer pump. Detailed Implementation

[0028] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] like Figure 1 As shown in Figure 2, a methanol fuel pressure balancing system of the present invention includes a methanol fuel daily use compartment 1, a first Tesla valve 201, a second Tesla valve 202, a nitrogen tank 3, a nitrogen control valve 4, a venting pipeline 5, a venting pipeline control valve 6, a venting collection compartment 7, a pressure balancing pipeline 8, a methanol fuel storage compartment 9, a liquid level alarm device 10, a methanol fuel transfer pipeline 11, and a methanol fuel transfer pump 12.

[0030] The methanol fuel storage tank 9 and the methanol fuel day tank 1 are located far apart. Methanol fuel storage tank 9 is usually located below the superstructure in the middle of the ship, while methanol fuel day tank 1 is located at the stern of the ship near the engine room.

[0031] The methanol fuel storage tank 9 and the methanol fuel day use tank 1 are equipped with independent pressure balancing pipelines 8 and first and second Tesla valves 201 and 202, which do not share pipelines with the vent pipes of the methanol fuel storage tank 9 and the methanol fuel day use tank 1.

[0032] The first and second Tesla valves 201 and 202 of the methanol fuel storage tank 9 and the methanol fuel day use tank 1 are connected by the pressure balancing pipeline 8. Due to the unidirectional conduction characteristics of the first and second Tesla valves 201 and 202, the methanol vapor and nitrogen mixture can pass through the first and second Tesla valves 201 and 202 well, thereby achieving pressure balance, while the methanol liquid cannot pass through the first and second Tesla valves 201 and 202. When the methanol fuel transfer pump 12 transfers methanol to the methanol fuel day use tank 1 through the methanol fuel transfer pipeline 11, no methanol liquid will overflow into the pressure balancing pipeline 8.

[0033] A venting line 5 is installed at the lowest point of the pressure balancing line 8. A venting line control valve 6 and a liquid level alarm device 10 are installed on the venting line 5. When methanol liquid is present in the pressure balancing line 8, the alarm signal of the liquid level alarm device 10 will be transmitted to the ship's monitoring and alarm system to remind the crew to open the venting control valve 6.

[0034] A venting pipe 5 is installed at the lowest point of the pressure balance pipe 8. Under low temperature conditions, methanol vapor condenses and is released into the venting collection chamber 7 through the venting pipe.

[0035] At the outlet of the first Tesla valve 201, nitrogen gas from the nitrogen tank 3 is connected through the nitrogen control valve 4. When necessary, the methanol liquid remaining in the pressure balance pipeline 8 can be purged with nitrogen gas.

[0036] The pressure balancing pipeline 8 mainly contains a mixture of methanol vapor and nitrogen. It can be installed on the main deck and uses a single-walled pipe, making the installation of the pressure balancing pipeline 8 more convenient.

[0037] Example:

[0038] The methanol fuel storage tank 9 is located away from the engine room, such as on large container ships, where it is located below the superstructure.

[0039] The methanol fuel day tank 1 is located at the stern of the ship near the engine room, which facilitates the use of shorter double-walled pipes to connect the methanol supply system to methanol users such as the main engine and auxiliary engines.

[0040] When the methanol fuel transfer pump 12 transfers methanol from the methanol fuel storage tank 9 to the methanol fuel day use tank 1, the pressure in the methanol fuel storage tank 9 decreases, while the pressure in the methanol fuel day use tank 1 increases. The pressurized nitrogen in the methanol fuel day use tank 1 enters the methanol fuel storage tank 9 through the first Tesla valve 201, the pressure balance pipe 8, and the second Tesla valve 202, thereby maintaining the pressure balance between the two tanks. At this time, no additional nitrogen injection is required, reducing the consumption of nitrogen.

[0041] When methanol fuel is supplied to methanol users such as main engine and auxiliary engine, the pressure of methanol fuel day use tank 1 will drop. At this time, nitrogen tank 3 will replenish the corresponding nitrogen to methanol fuel day use tank 1 through nitrogen control valve 4, so that the system pressure is kept within the design range.

[0042] Compared to traditional valves, Tesla valves have no moving parts and have good one-way flow characteristics. Methanol vapor and nitrogen can pass through the first and second Tesla valves 201 and 202, while pumped methanol liquid cannot pass through the first and second Tesla valves 201 and 202, thus preventing methanol liquid from entering the pressure balance pipe 8 and causing blockage of the pressure balance pipe 8.

[0043] Methanol can evaporate freely at room temperature. The methanol fuel pressure balance line 8 can be arranged on an open deck. When the ambient temperature is low, the methanol vapor will condense into liquid. A nitrogen inlet pipe is set after the first Tesla valve 201 to purge the methanol liquid in the balance line 8.

[0044] At the lowest point of the methanol fuel pressure balance pipeline 8, a venting pipeline 5 is installed, along with a liquid level alarm device 10. The alarm signal is transmitted to the engine room monitoring and alarm system, and the crew promptly opens the venting pipeline control valve 6 to release the methanol liquid into the venting collection tank 7.

[0045] Key technical points and protection points of this invention:

[0046] 1) This invention adopts a Tesla valve pressure balancing system, which fully considers the problem of methanol liquid blockage in long pipelines. It is equipped with a liquid level alarm device and a venting pipeline to ensure the normal operation of the pressure balancing system. This prevents the methanol vapor and nitrogen mixture in the methanol fuel day tank from being released into the air due to overpressure when the methanol fuel transfer pump injects methanol into the methanol fuel day tank, causing air pollution and wasting nitrogen.

[0047] 2) When the methanol fuel transfer pump transfers methanol from the methanol fuel storage tank to the methanol fuel day tank, ships without a methanol pressure balancing system need to supplement nitrogen to maintain the methanol fuel storage tank, which increases nitrogen consumption. With a pressure balancing pipe, the methanol fuel storage tank and the methanol fuel day tank can automatically balance the pressure during methanol fuel transfer, eliminating nitrogen consumption.

[0048] 3) The main protection points are the design of the pressure balance pipe, the application of the Tesla valve, and the setting of the methanol liquid alarm device.

Claims

1. A methanol fuel pressure balancing system, characterized in that: The system includes a methanol fuel day tank, a Tesla valve, a pressure balancing pipeline, and a methanol fuel storage tank. The methanol fuel storage tank and the methanol fuel day tank are connected by an independent pressure balancing pipeline and Tesla valve, and do not share pipelines with the vent pipes of the methanol fuel storage tank and the methanol fuel day tank. The Tesla valves of the methanol fuel storage tank and the methanol fuel day tank are connected by the pressure balancing pipeline. The methanol fuel storage tank and the methanol fuel day tank are also connected by a methanol fuel transfer pipeline and a methanol fuel transfer pump. A venting pipeline is installed at the lowest point of the pressure balancing pipeline, and a venting pipeline control valve and a liquid level alarm device are installed on the venting pipeline. When there is methanol liquid in the pressure balancing pipeline, the alarm signal of the liquid level alarm device is transmitted to the ship's monitoring and alarm system to remind the crew to open the venting control valve. Under low temperature conditions, methanol vapor condenses and is released into the venting collection tank through the venting pipeline. At the outlet of the Tesla valve of the methanol fuel day tank, a nitrogen gas supply from a nitrogen tank is connected through a nitrogen control valve to purge the methanol liquid remaining in the pressure balancing pipeline.

2. The methanol fuel pressure balancing system according to claim 1, characterized in that: The methanol fuel storage tank and the methanol fuel day tank are far apart. The methanol fuel storage tank is located below the superstructure in the middle of the ship, while the methanol fuel day tank is located near the engine room at the stern of the ship.

3. The methanol fuel pressure balancing system according to claim 1, characterized in that: The Tesla valve has a one-way conduction characteristic, allowing the methanol vapor and nitrogen mixture to pass through the Tesla valve to achieve pressure balance, while liquid methanol cannot pass through the Tesla valve. When the methanol fuel transfer pump transfers methanol to the methanol fuel day tank through the methanol fuel transfer pipeline, no liquid methanol will overflow into the pressure balance pipeline.

4. The methanol fuel pressure balancing system according to claim 1, characterized in that: The pressure balancing pipeline is located on the main deck and is a single-walled pipe through which a mixture of methanol vapor and nitrogen is circulated.

5. The methanol fuel pressure balancing system according to claim 1, characterized in that: When the methanol fuel transfer pump transfers methanol from the methanol fuel storage tank to the methanol fuel day tank, the pressure in the methanol fuel storage tank decreases and the pressure in the methanol fuel day tank increases. The sealing nitrogen in the methanol fuel day tank enters the methanol fuel storage tank through the Tesla valve and the pressure balance pipeline, thereby maintaining the pressure balance between the two tanks.

6. The methanol fuel pressure balancing system according to claim 1, characterized in that: When supplying methanol fuel to methanol users of the main and auxiliary engines, the pressure in the methanol fuel day tank will drop. At this time, the nitrogen tank will replenish the corresponding nitrogen to the methanol fuel day tank through the nitrogen control valve, so that the system pressure is maintained within the required range.

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