Marine ammonia fuel low-speed machine cabin safety protection system and ammonia gas leakage grading response method

Abstract

The invention discloses a marine ammonia fuel low-speed machine cabin safety protection system and an ammonia gas leakage grading response method. The system comprises a non-closed local protection cover surrounding a main engine cylinder cover area, and an air supply gap is formed between the non-closed local protection cover and a main engine body; the directional ventilation and purification subsystem is provided with an ammonia gas leakage monitoring sensor, a negative pressure suction unit and an ammonia gas spraying treatment unit which are positioned at the top of the protective cover, and can be automatically started when leakage is monitored, so that directional pumping, discharging, washing and purifying of ammonia gas are realized; and a nozzle of the independent host emergency spraying subsystem is mounted on the protective cover frame, is manually controlled by a person and is used for providing emergency spraying protection when the person is not evacuated. By means of a grading response mechanism combining automatic ventilation purification and manual emergency spraying, rapid control over ammonia gas leakage and personnel safety protection are achieved, and the system has the advantages of being rapid in response, efficient in control and emission, safe and reliable.

Description

Technical Field

[0001] This invention relates to the field of marine propulsion system safety protection technology, specifically to a safety protection system for the engine room of a marine ammonia-fueled low-speed engine and a graded response method for ammonia leaks. Particularly for ammonia leaks that may occur during the operation or shutdown of ammonia-fueled low-speed engines, it provides a comprehensive emergency response solution including local isolation, active extraction, and spray absorption to improve personnel safety and environmental controllability within the engine room. Background Technology

[0002] In response to the urgent need to address global warming and marine environmental protection, the International Maritime Organization (IMO) has clearly set decarbonization targets for the shipping industry: based on 2018 levels, global maritime average CO2 emissions should be reduced by 40% by 2030, and by 70% by 2050, achieving net-zero emissions by the end of this century. Against this backdrop, ammonia fuel, due to its zero-carbon combustion characteristics, is increasingly being regarded as one of the important clean energy sources for future ship propulsion systems, and related ammonia fuel engine technologies are in a stage of rapid development and practical application.

[0003] However, ammonia, a colorless gas with a strong, pungent odor, a density lower than air, and extremely soluble in water, poses a serious threat to the lives of personnel if it leaks in the confined environment of an engine room. Inhaling excessive amounts of ammonia can cause respiratory damage and even suffocation, while splashes of liquid ammonia can cause chemical burns. Currently, the engine room design of ships using low-speed ammonia-fueled engines generally lacks efficient local control and emergency response systems for ammonia leaks. Especially in high-risk leak areas such as the main engine cylinder head, neither physical isolation measures are in place, nor are directional ventilation and spray purification devices available to promptly remove and treat ammonia. In the event of a major leak such as a pipe rupture, ammonia can spread rapidly within the engine room, making it difficult to control quickly, severely impacting personnel evacuation and accident response, and posing significant safety hazards.

[0004] Therefore, there is an urgent need to propose a well-structured, responsive, safe and reliable integrated ventilation and spraying system for marine ammonia-fueled low-speed engines. By partially enclosing the leak source, monitoring in real time, actively extracting and absorbing the leak through spraying, the system can effectively limit the spread of ammonia gas, ensure the safe activities and working conditions of personnel in the engine room, and provide crucial safety assurance for the promotion of ammonia-fueled ships. Summary of the Invention

[0005] This invention addresses the shortcomings of existing safety protection systems for the engine room of marine ammonia-fueled low-speed engines by providing a safety protection system for the engine room of such engines and a graded response method for ammonia leaks, thereby solving the problems of difficult diffusion control and high personnel safety risks during ammonia leaks.

[0006] The technical solution of the present invention is as follows: A safety protection system for the engine room of a marine ammonia-fueled low-speed engine, characterized in that it includes: A protective cover is configured to surround the high-risk leakage area of ​​the cylinder head of the ammonia fuel low-speed engine. The partial protective cover includes a non-enclosed space consisting of a metal frame and a transparent enclosure. The metal frame is detachably fixed to the main engine bracket or engine compartment grille. The bottom and sides of the transparent enclosure form gaps with the main engine body for natural air intake. Ventilation handling unit, including: An ammonia leak monitoring sensor is installed in the top area of ​​the internal space of the local protective cover; The negative pressure suction unit includes a fan and a suction pipe. The suction inlet of the suction pipe is located at the highest point inside the protective cover. The inlet of the fan is connected to the inside of the partial protective cover through the suction pipe. An ammonia treatment unit is connected to the outlet of the blower through an exhaust pipe. The ammonia treatment unit is equipped with a first spraying mechanism for spraying and washing the ammonia-containing gas from the blower. A first control unit, electrically connected to the ammonia leak monitoring sensor and the fan, is configured to automatically start the fan when the ammonia leak monitoring sensor detects a concentration exceeding a first threshold; and a main unit emergency spray subsystem, independent of the ventilation treatment unit, includes: At least one emergency sprinkler head is mounted on the metal frame of the local protective cover, and the spray direction is toward the high-risk leakage area of ​​the cylinder head or the inner surface of the protective cover; A water supply pipeline, which is connected to the emergency sprinkler head; And a control valve, which is located on the water supply pipeline, to enable remote control.

[0007] Furthermore, the first control unit is also configured to: simultaneously start the fan and activate the first spray mechanism within the ammonia treatment unit; and automatically stop the fan and the first spray mechanism after the ammonia leak monitoring sensor detects that the concentration is below the second threshold for a predetermined period of time.

[0008] Furthermore, it also includes: an ammonia purification detection sensor, which is located at the exhaust port of the ammonia treatment unit; and a liquid collection unit, which includes a flow guiding and collecting device and an ammonia water collection tank located below the high-risk leakage area of ​​the cylinder head, wherein the flow guiding and collecting device is connected to the ammonia water collection tank for collecting ammonia-containing waste liquid from the emergency sprinkler head and / or the ammonia treatment unit.

[0009] Furthermore, the first spraying mechanism within the ammonia treatment unit uses water or an acidic solution as the spraying medium.

[0010] Furthermore, the emergency sprinkler head is located inside the protective cover, diagonally above and towards the exhaust side of the main engine cylinder head.

[0011] Furthermore, it also includes: multiple auxiliary isolation covers, which are respectively installed at the fuel line joints and valves of the ammonia fuel low-speed engine to prevent liquid ammonia from splashing.

[0012] Furthermore, the intake port of the air intake pipe is located in the central area of ​​the top of the protective cover, and its installation position is higher than that of the ammonia leak monitoring sensor.

[0013] Furthermore, the first control unit is also connected to the ammonia purification detection sensor and is configured to trigger a high-level alarm when the ammonia purification detection sensor detects that the ammonia concentration in the exhaust gas continuously exceeds the safety limit.

[0014] A graded response method for ammonia leakage based on the above system, characterized in that it includes: Automatic response phase: When the ammonia leak monitoring sensor detects that the ammonia concentration exceeds the first threshold, the first control unit automatically activates the directional ventilation and purification subsystem, performing negative pressure suction and spray washing operations; and Manual emergency response phase: When a leak occurs, if personnel are near the main unit, they can manually activate the main unit's emergency sprinkler subsystem by operating the manual control valve to form a localized sprinkler water curtain to assist personnel evacuation; after personnel have safely evacuated, they can manually close the manual control valve.

[0015] Furthermore, the start and stop of the manual emergency phase are completely independent of the control logic of the automatic response phase; the two can run simultaneously, separately, or only one of them can run.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1) Unlike traditional full-cabin dilution ventilation, this invention implements local physical containment of high-risk leakage sources on the ammonia fuel low-speed engine and establishes point-to-point negative pressure exhaust channels, which greatly reduces the contaminated space that needs emergency treatment, improves ammonia exhaust efficiency, and reduces the load and equipment scale of the overall ventilation system.

[0017] 2) Differentiated responses are implemented based on the leakage risk level and personnel status. The ventilation unit, based on sensor signals, achieves fully automatic start-up and operation, responsible for basic control, drainage, and purification in the event of a leak. The sprinkler system, serving as the last physical barrier for emergency personnel evacuation, employs a manual judgment activation mode to ensure direct and effective protection at the most critical moments, while avoiding malfunctions and water loss in unattended situations. Together, these two systems form a comprehensive safety coverage from accident warning to personnel evacuation.

[0018] 3) The protective cover not only serves as an isolation barrier, but also as a supporting structure for the ventilation system intake and an installation platform for the sprinkler heads and piping of the sprinkler system. This achieves a high degree of integration of safety function modules within a confined space, simplifies the layout, and improves the overall integrity and reliability of the system.

[0019] 4) It is not only applicable to the engine room safety protection of various types of ships that use ammonia as fuel, but can also be extended to land-based industrial sites such as diesel engine production and testing workshops where ammonia fuel equipment exists and leakage prevention is required. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the safety protection system for the engine room of a marine ammonia fuel low-speed engine of the present invention. Detailed Implementation

[0021] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments. These embodiments are used to explain the present invention, but not to limit its scope of protection.

[0022] The present invention is a ventilation and spraying system for marine ammonia-fueled low-speed engines, which is an integrated solution designed to meet the safety protection needs of marine low-speed diesel engines (hereinafter referred to as "main engines") fueled by ammonia in the engine room. The system is built around the cylinder head area (especially the high-pressure fuel line interface and the area near the injectors) on the main engine (1) where the risk of ammonia leakage is highest, and aims to achieve a closed-loop management of the entire process of "monitoring-isolation-extraction-purification-emergency protection" for leaked ammonia.

[0023] like Figure 1 As shown, the system mainly consists of the following four functional modules arranged collaboratively in space: Protective Cover 1: Covering the upper part of the main engine cylinder head, forming the first physical barrier. Protective Cover 1 adopts a modular design, with a lightweight, high-strength aluminum alloy frame as the main body and a transparent, impact-resistant acrylic panel for the enclosure structure. The transparent design facilitates daily inspections and observation of the internal situation in case of leakage. The frame is firmly installed on the main engine's own bracket or engine compartment fixed grid using bolts or special clamps, without requiring modification to the main engine body, making installation convenient and stable. The bottom edge of the protective cover maintains a gap of approximately 50-150mm with the surface of the main engine cylinder head, and appropriate gaps are also left between the side panels and other main engine components (such as the rocker arm box and turbocharger). This "partially sealed" design allows for natural airflow into the engine compartment to replenish the air, preventing excessively high negative pressure from forming inside the cover when the ventilation fan draws in air; on the other hand, in the initial stage of leakage, the airflow at this gap can form a certain "air curtain" effect, slightly slowing down the rate at which ammonia diffuses outward. The protective cover 1 can cover the upper space of one or more cylinder heads, enclosing key leakage risk points such as high-pressure ammonia oil pipe joints and injectors.

[0024] Ventilation handling unit, including: - Suction Piping and Inlet: One or more suction branch pipes connect from the center of the top of the protective cover 1 or slightly off-center from the expected leak point, converging into the main suction pipe. The suction inlet is designed as a flared or grilled type, located at the highest point inside the protective cover. Since ammonia is less dense than air, it will first rise after a leak; top suction achieves the most efficient capture of ammonia.

[0025] Ventilation Fan 2: Select a fan that conforms to ship specifications. Its air volume and pressure are calculated and determined based on the protective cover volume, the required air exchange rate, and the pipeline resistance. The ventilation fan can be installed on the engine room bulkhead, below the deck, or on a dedicated fan platform, and connected to the next-stage treatment equipment through exhaust pipes.

[0026] Tail gas treatment device 3 and the first spraying mechanism: The tail gas treatment device is an independent enclosure containing a spray tower or packed scrubbing tower structure. Ammonia-containing air from the ventilation fan enters from the bottom or middle of the tower. The first spraying mechanism (composed of a spray pump, pipelines, and multiple nozzles) sprays water or a low-concentration acidic solution (such as dilute sulfuric acid or dilute hydrochloric acid solution) downwards from the top of the tower. The ammonia gas is rapidly absorbed after sufficient contact with the spray liquid inside the tower. The acidic medium neutralizes the ammonia generated during absorption, improving absorption efficiency and capacity, and preventing ammonia evaporation.

[0027] Purification detection sensor 4: Installed on the clean gas outlet pipeline of the exhaust gas treatment device 3, it monitors the residual ammonia concentration in the treated gas in real time. This signal can be fed back to the control unit to monitor the treatment effect and can be linked to the alarm device.

[0028] Leakage monitoring sensor: At least one high-sensitivity ammonia concentration sensor is mounted on the frame above the inside of the protective enclosure to continuously monitor the environment inside. It has two thresholds: a low threshold for early warning and a high threshold to trigger emergency ventilation.

[0029] Emergency sprinkler head 5: Utilizing a wide-angle solid cone or fan-shaped nozzle, it is directly fixed to the aluminum alloy frame of the protective cover via a bracket, positioned diagonally above the exhaust side of the cylinder head, with the spray direction aimed at the cylinder head body and potentially leaking components. The number of sprinklers is determined based on the coverage area, typically 1-2 per cylinder head area. The sprinkler water supply pipe is also laid along the protective cover frame, connecting to a separate fire water pipe or a dedicated freshwater pressure tank. A manual quick-opening valve is installed on the pipeline as the sprinkler control valve. The operating handle of this valve is located outside the protective cover, in a safe position easily accessible to personnel and adjacent to the evacuation route, and is clearly marked. This sprinkler system is entirely based on manual judgment and operation, and is not connected to automatic control logic.

[0030] Ammonia Collection Pan 6: Installed on the engine deck below the main engine cylinder head area, this pan directs spray water and any leaked liquid ammonia to the ammonia collection tank. The tank's volume must meet the storage requirements for the maximum estimated waste liquid volume in a single accident and is equipped with a level alarm. Washing waste liquid from the bottom of the exhaust gas treatment unit 3 is also piped into this collection tank. Automatic control unit: Employs a PLC or dedicated safety controller. Receives signals from the leak detection sensor. When the concentration reaches a high threshold, it automatically executes: a) issuing an audible and visual alarm; b) starting the ventilation fan and the spray pump of the exhaust gas treatment device. Once the concentration drops to a safe low value and remains there for a period of time, the fan and pump automatically stop. If the signal from the purification detection sensor continues to exceed the limit, a high-level alarm is triggered, indicating a possible failure of the treatment device.

[0031] The workflow and operation method of this invention: 1. Normal state: The ventilation unit is in standby mode, and the main spray unit is off. Air inside the protective cover circulates naturally through the gaps.

[0032] 2. Ammonia leak occurred: -Automatic Response: The leak detection sensor detects a sudden increase in ammonia concentration exceeding the high threshold. The control unit immediately activates the audible and visual alarms and automatically starts the ventilation fan and the spray pump of the exhaust gas treatment device. The ammonia is rapidly extracted from the top of the protective enclosure, washed, purified, and then discharged.

[0033] - Emergency Response: If maintenance or inspection personnel are working on the main unit when a leak occurs, they should immediately assess the situation upon hearing / seeing the alarm. If they believe they are in direct danger (e.g., seeing liquid ammonia spray or feeling a strong irritation), they should evacuate along the pre-set safe route while simultaneously opening the manual quick-opening valve located on the evacuation path to activate the main unit's spray system. The spray water curtain can instantly absorb and suppress the ammonia cloud near the leak point, buying valuable evacuation time for personnel.

[0034] - Post-evacuation procedures: After all personnel have safely evacuated the cabin or reached a safe area, the evacuees, from a safe location or the control room, will remotely close the manual quick-opening valve to stop the main unit's spray system, conserving water and reducing waste liquid. The ventilation unit will continue to operate automatically until the leak is contained and the ammonia concentration inside the enclosure returns to a safe level.

[0035] 3. Post-incident handling: After the accident is handled, the waste liquid in the ammonia collection tank will be professionally treated. All system components will be inspected, reset, and prepared for the next operation.

[0036] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A safety protection system for the engine room of a marine ammonia-fueled low-speed engine, characterized in that, include: A protective cover is configured to surround the high-risk leakage area of ​​the cylinder head of the ammonia fuel low-speed engine. The partial protective cover includes a non-enclosed space consisting of a metal frame and a transparent enclosure. The metal frame is detachably fixed to the main engine bracket or engine compartment grille. The bottom and sides of the transparent enclosure form gaps with the main engine body for natural air intake. Ventilation handling unit, including: An ammonia leak monitoring sensor is installed in the top area of ​​the internal space of the local protective cover; The negative pressure suction unit includes a fan and a suction pipe. The suction inlet of the suction pipe is located at the highest point inside the protective cover. The inlet of the fan is connected to the inside of the partial protective cover through the suction pipe. An ammonia treatment unit is connected to the outlet of the blower through an exhaust pipe. The ammonia treatment unit is equipped with a first spraying mechanism for spraying and washing the ammonia-containing gas from the blower. A first control unit, electrically connected to the ammonia leak monitoring sensor and the fan, is configured to automatically start the fan when the ammonia leak monitoring sensor detects a concentration exceeding a first threshold; and a main unit emergency spray subsystem, independent of the ventilation treatment unit, includes: At least one emergency sprinkler head is mounted on the metal frame of the local protective cover, and the spray direction is toward the high-risk leakage area of ​​the cylinder head or the inner surface of the protective cover; A water supply pipeline, which is connected to the emergency sprinkler head; And a control valve, which is located on the water supply pipeline, enabling remote control.

2. The marine ammonia fuel low-speed engine room safety protection system according to claim 1, characterized in that, The first control unit is also configured to: simultaneously start the fan and activate the first spray mechanism within the ammonia treatment unit; and automatically stop the fan and the first spray mechanism after the ammonia leak monitoring sensor detects that the concentration is below the second threshold for a predetermined period of time.

3. The marine ammonia fuel low-speed engine room safety protection system according to claim 1 or 2, characterized in that, Also includes: An ammonia purification detection sensor is located at the exhaust port of the ammonia treatment unit; The system also includes a liquid collection unit, comprising a flow guiding and collecting device and an ammonia collection tank located below the high-risk leakage area of ​​the cylinder head. The flow guiding and collecting device is connected to the ammonia collection tank and is used to collect ammonia-containing waste liquid from the emergency sprinkler head and / or the ammonia treatment unit.

4. The marine ammonia fuel low-speed engine room safety protection system according to claim 1, characterized in that, The first spray mechanism in the ammonia treatment unit uses water or an acidic solution as the spray medium.

5. The marine ammonia fuel low-speed engine room safety protection system according to claim 1, characterized in that, The emergency sprinkler head is located inside the protective cover, diagonally above and towards the exhaust side of the main engine cylinder head.

6. The marine ammonia fuel low-speed engine room safety protection system according to claim 1, characterized in that, Also includes: Multiple auxiliary isolation shields are respectively installed at the fuel line joints and valves of the ammonia fuel low-speed engine to prevent liquid ammonia from splashing.

7. The marine ammonia fuel low-speed engine room safety protection system according to claim 1, characterized in that, The intake port of the air intake pipe is located in the central area of ​​the top of the protective cover, and its installation position is higher than that of the ammonia leak monitoring sensor.

8. The marine ammonia fuel low-speed engine room safety protection system according to claim 3, characterized in that, The first control unit is also connected to the ammonia purification detection sensor and is configured to trigger a high-level alarm when the ammonia purification detection sensor detects that the concentration of ammonia in the exhaust gas continuously exceeds the safety limit.

9. A graded response method for ammonia leakage based on the system according to any one of claims 1 to 8, characterized in that, include: Automatic response phase: When the ammonia leak monitoring sensor detects that the ammonia concentration exceeds the first threshold, the first control unit automatically activates the directional ventilation and purification subsystem, performing negative pressure suction and spray washing operations; and Manual emergency response phase: When a leak occurs, if personnel are near the main unit, they can manually activate the main unit's emergency sprinkler subsystem by operating the manual control valve to form a localized sprinkler water curtain to assist personnel evacuation; after personnel have safely evacuated, they can manually close the manual control valve.

10. The graded response method for ammonia leakage according to claim 9, characterized in that, The start and stop of the manual emergency phase are completely independent of the control logic of the automatic response phase; the two can run simultaneously, separately, or only one of them can run.

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