A leakage monitoring system for a methanol double-wall pipe annular inert space and a monitoring method thereof

Abstract

The application discloses a kind of methanol double-wall pipe annular inert space leak monitoring system and its monitoring method, the system includes double-wall pipe, leak detection unit, control box and engine methanol supply pipeline;Annular space is formed between the inner tube and outer tube of double-wall pipe and fills in nitrogen;Inner tube outlet is connected to engine methanol supply pipeline by valve group in leak detection unit;Leak detection unit is located at the lowest of methanol system, its bottom is equipped with liquid collecting tank, and methanol leaked by inner tube flows into liquid collecting tank through annular space;Pressure sensor and liquid level switch are installed on leak detection unit, respectively for monitoring annular space pressure and liquid collecting tank liquid level;Annular space is connected with inflation valve;Control box controls inflation valve opening and closing and engine operating mode according to pressure signal and liquid level signal, and sends alarm signal to AMS automation system.The application can accurately distinguish inner tube leakage and outer tube leakage, realize automatic air supply and engine mode switching, and ensure the operation safety of methanol fuel system.

Description

Technical Field

[0001] This invention relates to the field of ship methanol fuel supply system technology, specifically to a leakage monitoring system and monitoring method for methanol double-walled pipe ring filling inert space. Background Technology

[0002] Methanol has a low flash point, is highly explosive, and toxic. Therefore, methanol pipelines in safe areas of ships typically employ a double-walled pipe structure to enhance safety. Currently, the common safety measure in the annular space of a double-walled pipe is to create a sealed space and fill it with nitrogen at a certain pressure to form an inert protective environment. However, when a leak occurs in the inner or outer pipe of the double-walled pipe, how to promptly and accurately monitor the leak and take appropriate measures to prevent further spread of the leak's impact has become a pressing technical problem that needs to be solved.

[0003] Existing technologies lack effective solutions for distinguishing and monitoring leaks in the inner and outer pipes of double-walled pipe systems. Furthermore, they lack a linkage mechanism that can automatically control nitrogen replenishment and engine operating mode switching based on the leak type. This results in problems such as untimely monitoring response, inaccurate leak type identification, and inadequate safety control measures.

[0004] Therefore, it is necessary to provide a leakage monitoring system and monitoring method for methanol double-walled pipe ring filled with inert space to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a leakage monitoring system and method for methanol double-walled pipe ring filling inert space, which can accurately distinguish between inner pipe leakage and outer pipe leakage, realize automatic gas replenishment and engine mode switching, and ensure the safe operation of methanol fuel system.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A methanol double-walled pipe annular inert space filling leakage monitoring system includes: a double-walled pipe, a leakage detection unit, a control box, and an engine methanol supply pipeline; the double-walled pipe consists of an inner pipe and an outer pipe, forming an annular space for filling with nitrogen; the outlet of the inner pipe of the double-walled pipe is connected to the engine methanol supply pipeline through a valve group installed in the leakage detection unit; the leakage detection unit is located at the lowest position of the methanol system, and its bottom is provided with a collection tank for collecting leaked methanol; when the inner pipe leaks, the leaked methanol flows into the collection tank through the annular space; the leakage detection unit is equipped with a pressure sensor and a level switch. In this system, the pressure sensor is used to monitor the pressure within the annular space, and the level switch is used to monitor the liquid level in the collection tank. An inflation valve is connected to the annular space of the double-walled tube. The inlet of the inflation valve is connected to a nitrogen system, and the outlet is connected to the annular space, used to replenish nitrogen to the annular space. The control box is connected to the pressure sensor, level switch, inflation valve, and engine signal receiver. The control box controls the opening and closing of the inflation valve and the engine's operating mode based on the pressure signal monitored by the pressure sensor, and also controls the engine's operating mode based on the liquid level signal from the level switch. The control box is also connected to the AMS automation system to send alarm signals to the AMS automation system.

[0008] Preferably, the bottom of the collection tank of the leakage detection unit is provided with a vent valve for discharging the collected leaked methanol.

[0009] Preferably, it also includes a safety valve installed on the outside of the double-walled pipe, the safety valve being in communication with the annular space.

[0010] Preferably, the engine is a dual-fuel engine, and its operating modes include methanol mode and diesel mode.

[0011] A method for monitoring leakage in the methanol double-walled pipe ring filled with inert space based on the system includes the following steps:

[0012] S1. Fill the annular space of the double-walled tube with nitrogen gas at a pressure of 2 bar, and set the outer tube leakage monitoring pressure point to 1 bar and the inner tube leakage monitoring pressure point to 3 bar.

[0013] S2. The pressure in the annular space is monitored in real time by a pressure sensor, and the liquid level in the collection tank of the leakage detection unit is monitored by a liquid level switch.

[0014] S3. When the pressure drops to 1 bar after more than 4 hours, the control box controls the inflation valve to open and replenish nitrogen.

[0015] S31. If the pressure recovers to 2 bar within 5 minutes, the engine will continue to operate in methanol mode.

[0016] S32. If the pressure fails to recover to 2 bar within 5 minutes, the control box will switch the engine to diesel mode and send an external pipe leak alarm to the AMS automation system.

[0017] S4: When the pressure drops to 1 bar within 4 hours, the control box controls the engine to switch to diesel mode and sends an external pipe leak alarm to the AMS automation system;

[0018] S5: When the pressure exceeds 3 bar, the control box controls the engine to switch to diesel mode and sends an internal pipe leak alarm to the AMS automation system;

[0019] S6: When the liquid level switch is triggered, the control box controls the engine to switch to diesel mode and sends an internal pipe leak alarm to the AMS automation system.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. Through the coordinated monitoring of pressure sensors and level switches, it is possible to accurately distinguish between internal pipe leaks and external pipe leaks, avoid misjudgments, and improve the reliability of leak monitoring.

[0022] 2. By setting up a pressure drop delay gas replenishment mechanism and gas replenishment time judgment logic, it is possible to effectively identify external pipe leakage faults and promptly control the engine to switch to diesel mode, ensuring the safe operation of the ship's power system.

[0023] 3. Through the dual confirmation mechanism of internal pipe leakage pressure rise alarm and liquid level switch, it is ensured that internal pipe leakage can be detected in a timely manner and trigger a safety response. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the leakage monitoring system for the methanol double-walled tube ring filled with inert space according to the present invention;

[0025] Among them, 1-double-walled pipe, 2-leakage detection unit, 3-control box, 4-engine, 5-pressure sensor, 6-liquid level switch, 7-relief valve, 8-inflation valve, 9-inflation valve nitrogen system, 10-AMS automation system, 11-safety valve Detailed Implementation

[0026] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and not for limiting the scope of the invention. After reading this invention, any modifications of the invention in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0027] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixed connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] In this invention, terms such as "upper," "lower," "bottom," and "top" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are merely relational terms determined for the convenience of describing the structural relationship of the various components or elements of this invention, and do not specifically refer to any component or element in this invention, and should not be construed as limiting this invention.

[0029] like Figure 1 As shown, the present invention provides a leakage monitoring system for a methanol double-walled pipe ring inert space, including a double-walled pipe 1, a leakage detection unit 2, a control box 3, and an engine methanol supply pipeline.

[0030] The double-walled tube consists of an inner tube and an outer tube, forming an annular space between them. This annular space is filled with nitrogen to create an inert protective environment, preventing the risk of combustion or explosion in the event of a methanol leak. The outlet of the inner tube of the double-walled tube is connected to the engine's methanol supply line via a valve assembly located within the leak detection unit, ensuring that methanol fuel can be delivered to the engine normally.

[0031] The leak detection unit is located at the lowest point of the methanol system, with a collection tank at its bottom for collecting leaked methanol. When a leak occurs in the inner pipe, the leaked methanol flows into the collection tank under gravity through the annular space, facilitating centralized detection and handling. The leak detection unit is equipped with a pressure sensor 5 and a level switch 6. The pressure sensor monitors pressure changes within the annular space, while the level switch monitors the liquid level changes in the collection tank. A vent valve 7 is also installed at the bottom of the collection tank to discharge the collected leaked methanol.

[0032] The annular space of the double-walled tube is connected to an inflation valve 8. The inlet end of the inflation valve is connected to a nitrogen system 9, and the outlet end is connected to the annular space. This is used to replenish nitrogen to the annular space when the pressure drops, so as to maintain the inert protection pressure.

[0033] Control box 3 is connected to pressure sensor 5, level switch 6, inflation valve 8, and engine 4. The control box controls the opening and closing of the inflation valve and the engine's operating mode based on the pressure signal monitored by the pressure sensor, and also controls the engine's operating mode based on the level signal from the level switch. The control box is also connected to the AMS automation system 10 to send alarm signals to the AMS system, enabling operators to promptly obtain leakage information and take appropriate measures.

[0034] In addition, the system includes a safety valve 11 installed on the outside of the double-walled pipe. The safety valve is connected to the annular space and is used for pressure relief protection when the pressure in the annular space rises abnormally, preventing overpressure risks. The engine is a dual-fuel engine, with operating modes including methanol mode and diesel mode.

[0035] The leakage monitoring method for the methanol double-walled tubular ring inert space provided by this invention is based on the above system and specifically includes the following steps:

[0036] First, nitrogen gas at a pressure of 2 bar is introduced into the annular space of the double-walled tube, and the leakage monitoring pressure point of the outer tube is set to 1 bar, and the leakage monitoring pressure point of the inner tube is set to 3 bar. The pressure in the annular space is monitored in real time by a pressure sensor, and the liquid level in the collection tank of the leakage detection unit is monitored by a liquid level switch.

[0037] When the pressure drops to 1 bar after more than 4 hours, it indicates a slow decrease in nitrogen pressure within the annular space, possibly due to normal leakage. At this point, the control box opens the charging valve to replenish nitrogen. If the pressure recovers to 2 bar within 5 minutes, the nitrogen replenishment is normal, and the engine continues to operate in methanol mode. If the pressure fails to recover to 2 bar within 5 minutes, the nitrogen replenishment has failed, possibly due to a significant leak in the external pipeline. The control box switches the engine to diesel mode and sends an external pipeline leak alarm to the AMS automation system.

[0038] When the pressure drops to 1 bar within 4 hours, it indicates that the pressure drop in the annular space is relatively fast, which is directly determined to be an external pipe leak. The control box controls the engine to switch to diesel mode and sends an external pipe leak alarm to the AMS automation system.

[0039] When the pressure exceeds 3 bar, it indicates an abnormal increase in pressure within the annular space. The cause may be a leak in the inner tube, allowing high-pressure methanol to enter the annular space and causing the pressure to rise. The control box then switches the engine to diesel mode and sends an inner tube leak alarm to the AMS automation system.

[0040] When the liquid level switch is triggered, it indicates that the leaked methanol has been collected in the collection tank, which also confirms that the internal pipe is leaking. The control box controls the engine to switch to diesel mode and sends an internal pipe leak alarm to the AMS automation system.

[0041] Through the collaborative monitoring mechanism of the pressure sensor and liquid level switch, the system can accurately distinguish between internal pipe leakage and external pipe leakage, and automatically perform control actions such as gas replenishment, engine mode switching and alarm according to the type of leakage, effectively ensuring the safe operation of the methanol fuel system.

[0042] The foregoing description illustrates and describes preferred embodiments of the present invention. As previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A leakage monitoring system for methanol double-walled pipe ring filled with inert space, characterized in that, include: The system includes a double-walled pipe, a leak detection unit, a control box, and an engine methanol supply pipeline. The double-walled pipe consists of an inner and an outer pipe, forming an annular space for filling with nitrogen. The outlet of the inner pipe is connected to the engine methanol supply pipeline via a valve assembly located within the leak detection unit. The leak detection unit is positioned at the lowest point of the methanol system, and its bottom has a collection tank for collecting leaked methanol. When a leak occurs in the inner pipe, the leaked methanol flows into the collection tank through the annular space. The leak detection unit is equipped with a pressure sensor and a level switch. The pressure sensor is used to monitor... The pressure within the annular space is measured, and the level switch is used to monitor the liquid level in the collection tank. An inflation valve is connected to the annular space of the double-walled tube; the inlet of the inflation valve is connected to a nitrogen system, and the outlet is connected to the annular space, used to replenish nitrogen to the annular space. The control box is connected to the pressure sensor, level switch, inflation valve, and engine signal receiver. The control box controls the opening and closing of the inflation valve and the engine's operating mode based on the pressure signal monitored by the pressure sensor, and also controls the engine's operating mode based on the liquid level signal from the level switch. The control box is also connected to the AMS automation system to send alarm signals to the AMS automation system.

2. The leakage monitoring system for the methanol double-walled pipe ring filled with inert space according to claim 1, characterized in that: The bottom of the collection tank of the leakage detection unit is equipped with a vent valve for discharging the collected leaked methanol.

3. The leakage monitoring system for the methanol double-walled pipe ring filled with inert space according to claim 1, characterized in that; It also includes a safety valve installed on the outside of the double-walled pipe, which is in communication with the annular space.

4. The leakage monitoring system for the methanol double-walled pipe ring inert space according to claim 1, characterized in that; The engine is a dual-fuel engine, and its operating modes include methanol mode and diesel mode.

5. A method for monitoring leakage in the methanol double-walled tube ring filled with inert space based on the system according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Fill the annular space of the double-walled tube with nitrogen gas at a pressure of 2 bar, and set the outer tube leakage monitoring pressure point to 1 bar and the inner tube leakage monitoring pressure point to 3 bar. S2. The pressure in the annular space is monitored in real time by a pressure sensor, and the liquid level in the collection tank of the leakage detection unit is monitored by a liquid level switch. S3. When the pressure drops to 1 bar after more than 4 hours, the control box controls the inflation valve to open and replenish nitrogen. S31. If the pressure recovers to 2 bar within 5 minutes, the engine will continue to operate in methanol mode. S32. If the pressure fails to recover to 2 bar within 5 minutes, the control box will switch the engine to diesel mode and send an external pipe leak alarm to the AMS automation system. S4: When the pressure drops to 1 bar within 4 hours, the control box controls the engine to switch to diesel mode and sends an external pipe leak alarm to the AMS automation system; S5: When the pressure exceeds 3 bar, the control box controls the engine to switch to diesel mode and sends an internal pipe leak alarm to the AMS automation system; S6: When the liquid level switch is triggered, the control box controls the engine to switch to diesel mode and sends an internal pipe leak alarm to the AMS automation system.

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