Toxic ammonia gas absorption system for liquid ammonia fuel ship

Abstract

A toxic ammonia gas absorption system for a liquid ammonia fuel ship, comprising a toxic ammonia gas release source (100), an ammonia gas absorption tank (200), an ammonia gas guide pipe, and a diluted ammonia gas discharge pipe. The ammonia gas absorption tank (200) is provided with an absorbent (201), a gas diffusion layer (202), a liquid level switch (203), a gas phase space (206) and a temperature control device (207). The present system can improve the safety, environmental friendliness and economy of ships using ammonia fuel.

Description

Toxic ammonia gas absorption system for liquid ammonia fuel vessel TECHNICAL FIELD

[0001] The present application relates to the technical field of marine equipment, in particular to a toxic ammonia gas absorption technology for a vessel using ammonia gas as fuel. BACKGROUND

[0002] With the increasingly stringent environmental protection requirements faced by the global shipping industry, especially the target set by the International Maritime Organization to achieve net zero greenhouse gas emissions in the shipping industry by 2050, traditional fossil fuels have been unable to meet the sustainable development needs of the future shipping industry. Ammonia fuel, as a zero-carbon fuel, is considered as one of the ideal alternative fuels for the shipping industry due to its high energy density, easy storage and transportation, etc.

[0003] However, in the process of promoting the use of ammonia fuel, it is found that ammonia gas has high toxicity, and once it leaks, it is easy to threaten the health of the crew and the safety of the equipment. According to statistics, when the concentration of ammonia gas at normal temperature and pressure reaches 2700ppm, it can be fatal for people to stay in this environment for 10 minutes; when the concentration reaches 20-50ppm, it will cause human discomfort. Therefore, on ammonia fuel vessels, how to effectively control and handle the toxic ammonia gas leaked accidentally has become a key technical problem to be solved.

[0004] At present, the existing ammonia gas treatment technology for ships has some shortcomings. On the one hand, the traditional ammonia gas treatment equipment has low efficiency and cannot fully absorb and neutralize the leaked ammonia gas, resulting in excessive discharge of residual ammonia gas and harming the environment. On the other hand, these devices usually have complex structures and are not flexible enough in connection, making it difficult to adapt to the individual needs of different types and sizes of ships, limiting their popularization and application. In addition, the operation and maintenance of existing equipment are relatively cumbersome and have low automation, increasing the use cost.

[0005] In view of the above technical problems, it is urgent to develop a safe and efficient, environmentally friendly and reliable, flexible and practical ammonia gas leakage treatment system for ships. This system not only can quickly and effectively absorb and treat the leaked toxic ammonia gas to control the ammonia concentration within a safe range and protect the safety of the crew and equipment, but also has high ammonia gas absorption and conversion capacity to minimize the emission of residual ammonia and achieve environmental standards. At the same time, the system should have good adaptability and flexibility to be compatible with existing facilities on ships and meet the customization needs of different ship types. In addition, convenient operation and low-cost maintenance are also key factors.

[0006] In summary, the development of a ship ammonia gas leakage treatment system that meets the above requirements is of great significance to promote the safe application of ammonia fuel in the shipping industry and support the green and sustainable development of the industry, and will also bring new development opportunities to the field of ship design and manufacturing.

[0007] SUMMARY

[0008] The present application aims to provide a toxic ammonia gas absorption system for liquid ammonia fuel ships to solve the problems raised in the background art.

[0009] Specifically, in the embodiments of the present application, the toxic ammonia gas release source collects the ammonia gas leaked from the liquid ammonia fuel system of the ship and then introduces the ammonia gas into an ammonia gas absorption tank, which is provided with an absorbent for absorbing the ammonia gas and is provided with a liquid level switch for controlling the liquid level of the absorbent, so as to ensure that the ammonia gas absorption tank has sufficient gas phase space, and the ammonia gas absorption tank is further provided with a gas diffusion layer, which is arranged below the liquid level of the absorbent, the addition of the gas diffusion layer improves the absorption effect of the absorbent on ammonia, and the discharge of ammonia gas can be well controlled, and the ammonia gas absorption tank is further provided with a temperature control device for controlling the temperature in the tank, and the temperature control in the tank is necessary because lower temperature is more conducive to the absorption of ammonia by the absorbent.

[0010] An ammonia gas guide pipeline is connected at one end to the toxic ammonia gas release source and at the other end to the ammonia gas absorption tank and is arranged in the gas diffusion layer, so that the ammonia gas collected by the toxic ammonia gas release source must pass through the gas diffusion layer during the floating process after being introduced into the absorbent in the ammonia gas absorption tank.

[0011] A diluted ammonia gas discharge pipeline is used to guide the slowly released ammonia gas after absorption from the ammonia gas absorption tank and discharge it to the external environment.

[0012] There is no moving equipment in the present application, almost no maintenance is required for one-time installation, only liquid level and pressure need to be controlled, and automatic control can be realized; the mechanical structure in the ammonia gas absorption tank is simple, and the packing layer does not need to be replaced, and the equipment cost and operation cost are relatively low.

[0013] Preferably, the liquid level switch can realize liquid level control by adding a control valve at the water inlet or the water outlet.

[0014] Preferably, the gas diffusion layer can be a random packing or a structured packing, or even a wire mesh.

[0015] Optionally, the absorbent can be water, sodium hydroxide solution, etc., and when an absorbent other than water is selected, the absorbent cannot be connected to the fresh water tank and the ballast tank.

[0016] Optionally, the ammonia gas absorption tank can be a vertical container, so that the arrangement of the absorption tank can be reasonably optimized according to the area of the ship cabin.

[0017] The present application discloses a toxic ammonia gas absorption system for liquid ammonia fuel ships, comprising:

[0018] A source of toxic ammonia release for collecting ammonia gas leaked from a liquid ammonia fuel system of a ship;

[0019] An ammonia absorption tank, which is provided with an absorbent for absorbing the ammonia gas, and a liquid level switch for controlling the liquid level of the absorbent, thereby ensuring that the ammonia absorption tank has sufficient gas phase space, and is further provided with a gas diffusion layer, which is arranged below the liquid level of the absorbent, and a temperature control device for controlling the temperature in the tank;

[0020] An ammonia guiding pipeline, which is connected to the source of toxic ammonia release at one end and to the ammonia absorption tank below the gas diffusion layer at the other end, so that the ammonia gas collected by the source of toxic ammonia release must pass through the gas diffusion layer during its floating process after being introduced into the absorbent in the ammonia absorption tank;

[0021] A diluted ammonia discharge pipeline for discharging the ammonia gas slowly released after being absorbed by the absorbent from the ammonia absorption tank to the external environment.

[0022] In a preferred embodiment, the ammonia guiding pipeline comprises a gas phase ammonia discharge pipeline and a liquid phase ammonia discharge pipeline; the gas phase ammonia discharge pipeline is provided with a porous nozzle at its end to increase the diffusion efficiency of the ammonia gas in the absorbent.

[0023] In a preferred embodiment, the porous nozzle comprises a plurality of small holes uniformly distributed along its circumference for dispersing the ammonia gas in the ammonia guiding pipeline into small bubbles to increase the contact area between the ammonia gas and the absorbent and improve the ammonia absorption efficiency.

[0024] In a preferred embodiment, the gas diffusion layer comprises a filler and is connected to the inner wall of the ammonia absorption tank by a positioning buckle.

[0025] In a preferred embodiment, the diluted ammonia discharge pipeline comprises a gas permeable tube and a gas permeable mast connected in sequence, one end of the gas permeable tube is connected to the gas phase space inside the ammonia absorption tank, and the other end is connected to the gas permeable mast for guiding the ammonia gas slowly released after being absorbed by the absorbent in the gas phase space inside the ammonia absorption tank to the gas permeable mast to be discharged to the atmospheric environment.

[0026] In a preferred embodiment, the ammonia absorption tank is provided with a temperature control device for adjusting the liquid temperature after absorbing the ammonia gas to maintain a stable absorption rate.

[0027] In a preferred embodiment, the air breather mast end is provided with an absorbent spray system for further neutralizing the concentration of ammonia gas discharged by the ammonia gas absorption tank into the air breather pipe, and the waste liquid generated by the spray system is returned to the ammonia gas absorption tank through the diluted ammonia gas discharge pipeline.

[0028] In a preferred embodiment, the ammonia gas absorption tank is also provided with an inlet water hole and an outlet water hole for circulating update of the absorbent absorption to maintain the ammonia gas absorption efficiency.

[0029] In a preferred embodiment, the water source of the inlet water hole is a fresh water tank, and the downstream of the outlet water hole is a ballast tank.

[0030] In a preferred embodiment, the source of toxic ammonia gas release is selected from the group consisting of a receiving disc, a liquid ammonia fuel tank pressure relief valve, a double-wall pipe ammonia gas discharge port, an air breather mast water spray system waste water, and a confined space containing ammonia gas fuel.

[0031] In a preferred embodiment, the liquid level switch controls the liquid level of the absorbent to ensure that the volume of the gas phase space in the ammonia gas absorption tank is at least 20% of the total volume of the ammonia gas absorption tank.

[0032] Compared with the prior art, the embodiments of the present application have at least the following differences and effects:

[0033] Firstly, the safety of ships using ammonia fuel is significantly improved. The system effectively collects and absorbs the toxic ammonia gas leaked accidentally by setting up the ammonia gas absorption tank and related guide and discharge pipelines. The ammonia gas concentration in the environment can be quickly reduced to a safe range by using water absorption and neutralization reaction, avoiding poisoning of personnel and damage to equipment, thereby enhancing the overall safety of the ship.

[0034] Further, the ammonia gas treatment efficiency is improved and the discharge is reduced. The gas diffusion layer is provided in the ammonia gas absorption tank, which cooperates with the porous nozzle at the end of the gas phase ammonia discharge pipeline to strengthen the full contact and mass transfer of ammonia gas and water, thereby improving the absorption efficiency. At the same time, the gas-liquid contact area is maintained in the water tank, and the volume of the water tank is reduced. After treatment, most of the ammonia gas is converted into ammonium hydroxide solution, and the ammonia gas slowly released after being absorbed by the absorbent is discharged to a safe area through the discharge pipe, thereby minimizing the release of toxic ammonia.

[0035] Further, the system connection is flexible and has strong adaptability. The system can be flexibly connected to potential ammonia gas leakage sources such as pipelines, valves, and storage tanks according to the layout of the ship to ensure comprehensive coverage and rapid response. The system design is compatible with the existing structure and operation process of the ship, and can be applied to various types and sizes of ships. In addition, the modular design of the system makes it adjustable according to different ship scales and needs, providing a highly customized solution.

[0036] Further, it is easy to operate and maintain, and low in cost. Compared with other ammonia treatment technologies, the system has a simple device structure, can realize automatic control, quickly starts when leakage occurs, and only needs to be regularly replenished with water and overhauled, which is simple to operate and highly reliable. The design of the water tank takes into account the recycling and waste water treatment of water, and the water source can use the existing fresh water system, sea water system or other water sources on the ship, which is economical and practical.

[0037] Further, the environmental benefits are significant. Through chemical neutralization reaction, ammonia gas is converted into ammonium hydroxide, which not only reduces the harm of toxic ammonia gas emissions to the environment, but also supports the International Maritime Organization's goal of achieving net zero greenhouse gas emissions in the shipping industry by 2050, which is of great significance to environmental protection.

[0038] In summary, the toxic ammonia gas absorption system for liquid ammonia fuel ships provided by the present application is safe and reliable, highly efficient and environmentally friendly, easy to operate and maintain, and has strong applicability, which can effectively control the risk of ammonia fuel leakage, promote the safe application of ammonia fuel in the shipping industry, and provide important support for the sustainable development of the shipping industry, and has a broad application prospect.

[0039] A large number of technical features are described in the specification of the present application, which are distributed in various technical solutions. If all possible combinations of technical features (i.e. technical solutions) of the present application are listed, the specification will be too long. In order to avoid this problem, each technical feature disclosed in the above content, each technical feature disclosed in the following embodiments and examples, and each technical feature disclosed in the drawings can be freely combined to form various new technical solutions (these technical solutions are considered to have been described in the specification), unless such combination of technical features is technically infeasible. For example, features A+B+C are disclosed in one example, features A+B+D+E are disclosed in another example, features C and D are equivalent technical means that play the same role, and can only be used at the same time, and feature E can be combined with feature C technically. Therefore, the scheme of A+B+C+D should not be considered to have been described because it is technically infeasible, and the scheme of A+B+C+E should be considered to have been described. BRIEF DESCRIPTION OF DRAWINGS

[0040] FIG. 1 is a structural schematic diagram of a toxic ammonia gas absorption system for a liquid ammonia fuel ship according to a first embodiment of the present application.

[0041] FIG. 2 is an exemplary structural schematic diagram of a nozzle in the toxic ammonia gas absorption system for a liquid ammonia fuel ship according to the first embodiment of the present application.

[0042] In all the drawings, the same reference signs are used to indicate the same elements or structures, wherein: 100: toxic ammonia release source 101: receiving tray 102: liquid ammonia fuel tank pressure relief valve 103: double-walled pipe ammonia vent 104: vented mast water spray system wastewater 105: enclosed space containing ammonia fuel 200: ammonia absorption tank 201: absorbent 202: diffusion layer 203: liquid level switch 204: water inlet hole 205: water outlet hole 206: gas phase space 301: gas phase ammonia discharge pipeline 302: liquid phase ammonia discharge pipeline 303: check valve 304: nozzle 401: vent pipe 402: vented mast 403: water spray system DETAILED DESCRIPTION

[0043] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without some or all of these specific details, and that the scope of the present application is not limited to the embodiments set forth below.

[0044] Some of the innovations of the present application are summarized as follows:

[0045] The inventors of the present application have conducted extensive and in-depth research, and in view of the safety and environmental challenges faced by the current shipping industry in using liquid ammonia fuel, an innovative toxic ammonia absorption system is proposed. The design concept of this system is based on the following core innovations:

[0046] 1. Special design of ammonia absorption tank:

[0047] 1) Gas diffusion layer: An innovative gas diffusion layer is installed inside the ammonia absorption tank, which is mainly composed of, for example, multiple layers of packing, to enhance the contact area between ammonia and absorbent. The diffusion layer is located in the middle or lower part of the tank body to ensure that all ammonia entering the tank through the pipeline must pass through this layer, thereby increasing the contact time and area of ammonia and water and improving the efficiency of chemical absorption.

[0048] 2) Liquid level control system: High-precision liquid level switches are equipped to monitor the height of the absorbent in the tank in real time, ensuring that there is enough amount of absorbent to absorb ammonia, while maintaining the necessary gas phase space to avoid excessive pressure.

[0049] 2. Ammonia guiding pipeline and porous nozzle:

[0050] 1) Ammonia guiding pipeline: A specially designed ammonia guiding pipeline connects the ammonia release source and the ammonia absorption tank. The pipeline is designed as a double-channel system, including separate processing channels for gas and liquid phase ammonia, to ensure that all types of ammonia leaks are effectively introduced into the absorption system.

[0051] 2) Multi-hole nozzle: A multi-hole nozzle is installed at the end of the ammonia gas exhaust pipe. The nozzle is designed with multiple small holes to evenly disperse the ammonia gas into tiny bubbles in the water tank, increasing the contact area between ammonia gas and water and accelerating the chemical reaction speed.

[0052] 3. Air-permeable mast and water spray system:

[0053] 1) Air-permeable mast: Installed above the ammonia gas absorption tank, it is used to safely discharge treated ammonia gas outside the ship. The design of the air-permeable mast takes into account efficient gas release while preventing ammonia gas accumulation on the ship.

[0054] 2) Water spray system: A water spray system is installed at the end of the air-permeable mast to further neutralize the discharged ammonia gas. This system can spray fine water droplets to react with ammonia gas when needed, reducing the concentration of ammonia gas to a safe level.

[0055] These structural technical means together constitute a complete solution, aiming to improve the safety and environmental friendliness of liquid ammonia fuel ships during use. Each technical means is optimized in design according to the characteristics of ammonia gas and the needs of the ship's operating environment, ensuring that the system is both efficient and reliable.

[0056] In summary, the toxic ammonia gas absorption system of the present application has obvious practical application advantages with its innovative technical concept and significant effects in improving shipping safety, operational convenience and environmental friendliness, and is expected to be widely applied in the shipping industry.

[0057] In the following description, many technical details are presented to help the reader better understand the present application. However, those skilled in the art can understand that the technical solutions claimed in the claims of the present application can be realized even without these technical details and based on various changes and modifications of the following embodiments. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0058] Explanation of some concepts:

[0059] Toxic ammonia gas release source refers to the location or equipment on the liquid ammonia fuel ship where ammonia gas leakage may occur, including liquid ammonia storage tank, pipeline, valve, pump, etc. In this application, it mainly refers to the receiving disc, liquid ammonia fuel tank pressure relief valve, double-wall pipe ammonia gas discharge port, air-permeable mast water spray system waste water and ammonia gas-containing enclosed space, etc.

[0060] Ammonia absorption tank, in the present application, is used to absorb and neutralize the leaked ammonia. The water tank is filled with absorbent, and is provided with water inlet and outlet, which are connected with the ship's fresh water tank and ballast tank, so as to realize the automatic supply and recycling of the absorption liquid. Optionally, the absorbent can be fresh water, sodium hydroxide solution, ammonia water, calcium hydroxide solution, etc.

[0061] Gas diffusion layer, in the present application, refers to a porous partition structure installed in the ammonia absorption tank, which is optionally made of multiple layers of stainless steel mesh. Its function is to strengthen the contact between ammonia and absorption liquid, prolong the residence time of ammonia in water, and thus improve the absorption efficiency.

[0062] Ammonia guiding pipeline, in the present application, refers to the pipeline connecting the toxic ammonia release source and the ammonia absorption tank, which introduces the leaked ammonia into the absorption tank for treatment. Optionally, the guiding pipeline is divided into gas phase ammonia discharge pipeline and liquid phase ammonia discharge pipeline, which transport gaseous and liquid ammonia respectively. Among them, the gas phase ammonia discharge pipeline is provided with a porous nozzle at the end, which is used to disperse ammonia into fine bubbles, improving the mass transfer effect.

[0063] Porous nozzle, in the present application, refers to a special nozzle installed at the end of the gas phase ammonia discharge pipeline, which is provided with multiple small holes on the surface. When the ammonia-containing gas passes through the porous nozzle, it will be dispersed into a large number of tiny bubbles, significantly increasing the gas-liquid contact area and accelerating the absorption reaction rate.

[0064] Diluted ammonia discharge pipeline, in the present application, refers to the pipeline connecting the gas phase space at the top of the ammonia absorption tank and the atmospheric environment, which is used to discharge the ammonia slowly released after being absorbed by the absorbent to the atmosphere.

[0065] Liquid level switch, in the present application, refers to a liquid level control device installed in the ammonia absorption tank, which is used to adjust the liquid level height of the absorption liquid in the tank in real time. When the liquid level drops to the lower limit, the switch automatically opens the water inlet to supplement fresh water to the upper limit position, and then closes the water inlet to maintain the gas-liquid ratio in the tank and ensure the absorption effect.

[0066] Temperature control device, in the present application, refers to a heat exchanger that removes heat through a heat carrier, which is used to maintain the stability of the tank temperature.

[0067] In order to make the purpose, technical scheme and advantages of the present application more clear, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0068] First embodiment

[0069] Referring to FIG. 1 and FIG. 2, the toxic ammonia absorption system for liquid ammonia fuel ship of the present embodiment comprises:

[0070] Toxic ammonia release source 100, used to collect the leaked ammonia of the ship's liquid ammonia fuel system.

[0071] An ammonia absorption tank 200, which is provided with an absorbent 201 for absorbing the ammonia, and is provided with a liquid level switch 203 for controlling the liquid level of the absorbent 201, so as to ensure that the ammonia absorption tank 200 has sufficient gas phase space 206, and is further provided with a gas diffusion layer 202, which is arranged below the liquid level of the absorbent 201, and is further provided with a temperature control device 207, which is a heat exchanger for taking away the absorption heat in the tank by using low-temperature water.

[0072] An ammonia guiding pipeline, one end of which is connected to the toxic ammonia release source 100, and the other end of which is connected to the ammonia absorption tank 200 and is arranged below the gas diffusion layer 202, so that the ammonia collected by the toxic ammonia release source 100 will inevitably pass through the gas diffusion layer 202 during the floating process after being introduced into the absorbent 201 of the ammonia absorption tank 200.

[0073] A diluted ammonia discharge pipeline, which is used to guide the ammonia slowly released after being absorbed by the absorbent 201 in the ammonia absorption tank 200 to the outside environment.

[0074] Further, in the toxic ammonia absorption system for the liquid ammonia fuel ship of the embodiment, the toxic ammonia release source 100 refers to the position or equipment on the ship that may leak ammonia, such as the pressure relief valve of the liquid ammonia fuel tank, the discharge port of the double-wall pipe, etc. The toxic ammonia generated by these leakage sources needs to be collected and treated. The ammonia absorption tank 200 is the core component of the system, which contains the absorbent 201 for absorbing ammonia. The ammonia absorption tank 200 is provided with a liquid level switch 203 for controlling the liquid level of the absorbent, so as to ensure that the ammonia absorption tank has sufficient gas phase space 206 for collecting ammonia. In addition, the ammonia absorption tank 200 is further provided with a gas diffusion layer 202, which is arranged below the liquid level of the absorbent. The function of the gas diffusion layer is to increase the residence time and diffusion degree of ammonia in the absorbent, and to improve the absorption efficiency. The ammonia guiding pipeline is composed of a gas phase ammonia discharge pipeline 301 and a liquid phase ammonia discharge pipeline 302, which guides the ammonia generated by the toxic ammonia release source 100 into the ammonia absorption tank 200. The outlet of the guiding pipeline is located below the gas diffusion layer 202, so that the ammonia will inevitably pass through the diffusion layer during the floating process, and be fully diffused and dissolved in the absorbent. The diluted ammonia discharge pipeline is composed of a gas permeable pipe 401 and a gas permeable mast 402, which discharges the ammonia slowly released after being absorbed by the absorbent 201 in the ammonia absorption tank 200 to the outside environment, which is generally discharged to high altitude through the gas permeable mast to dilute the concentration.

[0075] The toxic ammonia absorption system for the liquid ammonia fuel ship of the embodiment will be further explained as follows.

[0076] Optionally, the ammonia guiding pipeline comprises a gaseous ammonia discharge pipeline 301 and a liquid ammonia discharge pipeline 302; the gaseous ammonia discharge pipeline 301 is provided with a porous nozzle 304 at the end thereof to increase the diffusion efficiency of the ammonia in the absorbent 201.

[0077] Optionally, the porous nozzle 304 comprises a plurality of small holes uniformly distributed along the circumference thereof, which are used to disperse the ammonia in the ammonia guiding pipeline into small bubbles to increase the contact area of the ammonia with the absorbent 201 and improve the ammonia absorption efficiency.

[0078] Further, the ammonia guiding pipeline can comprise two parts: the gaseous ammonia discharge pipeline 301 and the liquid ammonia discharge pipeline 302. The gaseous ammonia discharge pipeline 301 is mainly used to transport the gaseous ammonia released by the leakage source, while the liquid ammonia discharge pipeline 302 is used to transport the liquid ammonia released by the leakage source. In this way, the corresponding guiding pipeline can be selectively used according to the specific form of ammonia leakage to improve the applicability of the system.

[0079] As described above, in one optional example, a special porous nozzle 304 is designed at the end of the gaseous ammonia discharge pipeline 301. The porous nozzle 304 is used to further disperse the ammonia transported by the pipeline into small bubbles, thereby greatly increasing the contact area of the ammonia with the absorbent 201, strengthening the dissolution and absorption process of the ammonia, and ultimately improving the ammonia absorption efficiency of the entire system.

[0080] According to the structure of the porous nozzle 304 described above, a plurality of small holes are uniformly distributed on the outer wall of the porous nozzle 304. When the ammonia enters the porous nozzle 304 from the pipeline, it will be dispersed into countless small bubbles through these small holes to form a "bubble plume". Compared with directly discharging a large amount of ammonia into the absorbent, this bubble dispersion can significantly increase the residence time and diffusion range of the ammonia in the absorbent, allowing it to fully contact and react with the absorbent and be absorbed to the maximum extent. At the same time, the uniform distribution of the small holes helps to uniformly diffuse the ammonia in the tank cross section, avoiding excessive local ammonia concentration that affects the absorption effect.

[0081] In general, by setting the porous nozzle 304 at the end of the gaseous ammonia discharge pipeline 301 and ingeniously designing the micro-hole structure of the porous nozzle 304, the dissolution and absorption process of the ammonia can be significantly strengthened, and the ammonia absorption conversion efficiency and processing capacity of the absorbent can be improved. In actual application, the pore size, hole density, and other parameters of the porous nozzle 304 can be flexibly adjusted according to factors such as the amount of ammonia leakage and the size of the tank to obtain the best dispersion and absorption effect.

[0082] It should be noted that the multi-hole nozzle 304 is not limited to this, and in other embodiments of the present application, the multi-hole nozzle 304 can be composed of multiple nozzle tubes, and different shapes and sizes of spray holes can be arranged on each nozzle tube according to different intervals as needed.

[0083] For example, in addition to simple circular holes, the spray holes can also be designed in other shapes such as elliptical, triangular, polygonal, etc. Spray holes of different shapes will have differences in atomization performance, pressure drop characteristics, etc. In addition, variable diameter holes can be used, i.e. the inlet and outlet diameters of the spray holes are different, forming a structure similar to a Venturi tube, which helps to improve the atomization effect and anti-clogging ability.

[0084] For another example, on the basis of basic uniform distribution, gradient distribution can be used, i.e. the hole diameter or hole spacing of the spray holes gradually changes from the center of the nozzle to the edge (i.e. from the starting end of the nozzle tube close to the center of the nozzle to the end far from the center of the nozzle), forming different atomization zones. It can also be designed in special forms such as spiral distribution, snake distribution, etc. to produce a swirling effect and strengthen gas-liquid mixing.

[0085] Optionally, the gas diffusion layer 202 comprises multiple layers of stainless steel wire mesh and is connected to the inner wall of the ammonia gas absorption tank 200 by a positioning buckle.

[0086] Further, the gas diffusion layer 202 is one of the key components for improving the ammonia gas absorption efficiency. In this embodiment, the gas diffusion layer 202 adopts a structure of multiple layers of stainless steel wire mesh. Compared with a single layer of mesh plate, the multiple layers of stainless steel wire mesh have a larger specific surface area and a more complex pore structure, which can further prolong the residence time of ammonia gas in water, strengthen the full contact and mass transfer process of ammonia gas and water.

[0087] Specifically, the gas diffusion layer 202 can be composed of several layers of parallel arranged stainless steel wire mesh, and the size and distribution of the mesh holes of each layer can be optimized and designed according to actual needs. After the ammonia bubbles enter the diffusion layer from below, they will constantly detour and rise in the gaps between the layers, contacting more water molecules, thereby accelerating the dissolution and absorption rate. At the same time, the stainless steel wire mesh has good corrosion resistance and mechanical strength, and can stably work in the humid environment of the water tank for a long time.

[0088] As can be seen, using stainless steel wire mesh as the diffusion layer material has the following advantages:

[0089] 1) The stainless steel wire mesh has good mechanical strength and corrosion resistance, and can stably work in the ammonia water environment for a long time.

[0090] 2) The mesh size of the stainless steel wire mesh can be adjusted according to actual needs, and by selecting an appropriate mesh size, the ammonia gas diffusion effect can be ensured while the water flow resistance is minimized and the energy consumption is reduced.

[0091] 3) The arrangement of multiple layers of stainless steel wire mesh can significantly increase the residence time and mass transfer area of ammonia gas in water. During the process of passing through each layer of stainless steel wire mesh, ammonia gas is continuously dispersed and broken, forming more and smaller bubbles, thereby accelerating the absorption and reaction rate.

[0092] Further, in order to reliably fix the gas diffusion layer 202 at a specific position inside the water tank, a positioning buckle mechanism is also designed in this embodiment. Through the positioning buckle, the gas diffusion layer 202 can be firmly connected to the inner wall of the water tank 200, avoiding displacement or deformation due to water flow impact or vibration. The number and distribution of the positioning buckles can be reasonably designed according to the size and stress condition of the diffusion layer, ensuring the stability of the entire diffusion layer structure.

[0093] In summary, using multiple layers of stainless steel wire mesh as the material of the gas diffusion layer 202 and fixing it inside the water tank through positioning buckles can significantly enhance the diffusion and absorption effect of ammonia gas, while having high structural reliability and service life. In practical applications, the performance of the diffusion layer can be optimized by adjusting the number of layers, mesh parameters, etc. of the stainless steel wire mesh, thereby further improving the processing efficiency and stability of the entire ammonia gas absorption system. For example, when the number of layers of stainless steel wire mesh is 3 to 5, and the mesh size is 0.8 to 1.2 mm, the diffusion and absorption effect of ammonia gas can be further enhanced.

[0094] It should be noted that in the embodiments of the present application, the gas diffusion layer is not limited to multiple layers of stainless steel wire mesh or multiple layers of other metal wire mesh, but can also be random packing or structured packing. For example, common random packings such as Raschig rings, Pall rings, or Intalox saddle rings can be used; structured packings such as structured corrugated plate packings, structured hole plate packings, or structured wire mesh packings can also be used. These packings can effectively increase the gas-liquid contact area and prolong the residence time of ammonia gas in the absorbent, thereby improving the absorption efficiency. When selecting a specific type of packing, factors such as specific surface area, void fraction, pressure drop, cost, and compatibility with ammonia gas need to be considered.

[0095] Optionally, the diluted ammonia gas discharge pipeline includes a gas permeable pipe 401 and a gas permeable mast 402 connected in sequence, one end of the gas permeable pipe 401 is connected to the gas phase space 206 inside the ammonia gas absorption tank 200, the other end is connected to the gas permeable mast 402, for guiding the ammonia gas slowly released from the gas phase space 206 inside the ammonia gas absorption tank 200 after being absorbed by the absorbent 201 to the gas permeable mast 402, to be discharged to the atmospheric environment.

[0096] Optionally, the ammonia absorption tank 200 is provided with a temperature control device 207 for adjusting the temperature of the absorbent 201. When the absorbent 201 absorbs ammonia, an exothermic reaction occurs, causing the temperature to rise. In order to maintain optimal absorption efficiency, the temperature control device 207 can maintain the temperature of the absorbent 201 within a predetermined ideal range.

[0097] Optionally, the end of the gas permeable mast 402 is provided with a water spraying system 403 for further neutralizing the concentration of ammonia gas discharged by the ammonia absorption tank 200 into the gas permeable pipe 401, and the wastewater generated by the water spraying system 403 is returned to the ammonia absorption tank 200 through the diluted ammonia gas discharge pipeline, but not limited to this, in other embodiments of the present application, it can also be returned to the ammonia absorption tank 200 through the liquid phase ammonia discharge pipeline 302.

[0098] Further, as shown in FIG. 1, one end of the gas permeable pipe 401 is connected to the gas phase space 206 inside the water tank 200, and the other end is connected to the gas permeable mast 402. During the floating process, the ammonia gas in the water tank is fully contacted and reacted with water through the gas diffusion layer 202, and most of the ammonia gas is removed by absorption. However, the ammonia gas slowly released after being absorbed by the absorbent 201 enters the gas phase space 206 at the top of the tank. In order to avoid the accumulation of this part of ammonia gas in the tank, it is guided to the gas permeable mast 402 through the gas permeable pipe 401, and finally discharged to the atmospheric environment.

[0099] The gas permeable pipe 401 is made of corrosion-resistant and high-temperature-resistant materials such as stainless steel and polytetrafluoroethylene.

[0100] The gas permeable mast 402 is vertically arranged and is higher than the deck of the ship by a certain height. The height of the mast and the position of the outlet should be reasonably designed according to the model of the ship and the environmental conditions of the navigation area to ensure that the discharged ammonia gas does not harm the crew and equipment.

[0101] At the end of the gas permeable mast 402, a water spraying system 403 is also provided, as shown in FIG. 1. For example, the water spraying system 403 can be composed of several spraying heads, which are in communication with the fresh water pipeline. When the ammonia gas is discharged from the gas permeable mast 402, the spraying system 403 sprays atomized fresh water into the gas flow, which further absorbs and dilutes the ammonia gas, thereby further reducing the concentration of the discharged ammonia gas and reducing the impact on the environment.

[0102] The ammonia-containing wastewater generated by the spraying system 403 is returned to the ammonia absorption tank 200 through the diluted ammonia gas discharge pipeline, realizing the recycling of water. The returned ammonia-containing wastewater enters the water tank and mixes with the absorbent 201 in the tank, without affecting the normal operation of the water tank.

[0103] Thus, by setting the air pipe 401 and the air mast 402, the ammonia gas slowly released after being absorbed is discharged to the atmospheric environment, and the ammonia gas concentration is further diluted by the water spraying system 403 to ensure that the discharge meets the standard. At the same time, the sprayed wastewater is returned to the absorption tank, realizing the recycling of water resources and reducing wastewater discharge.

[0104] Optionally, the ammonia gas absorption tank 200 is also provided with a water inlet hole 204 and a water outlet hole 205 for the recycling and updating of the absorbent 201 to maintain the ammonia gas absorption efficiency.

[0105] Optionally, the water source of the water inlet hole 204 is a fresh water tank, and the downstream of the water outlet hole 205 is a ballast tank.

[0106] Further, in order to maintain the ammonia gas absorption efficiency of the absorbent 201 in the ammonia gas absorption tank 200, the absorbent needs to be periodically recycled and updated. In this embodiment, the water tank 200 is provided with a special water inlet hole 204 and a water outlet hole 205 for realizing the recycling of the absorbent.

[0107] The water inlet hole 204 is located at the upper part of the water tank and is used to supplement fresh absorbent into the water tank. The water source for supplementing can be selected from a fresh water tank on the ship. The water stored in the fresh water tank is generally clean water after treatment and is suitable for ammonia gas absorption. Through the water inlet hole 204, the water in the fresh water tank can be continuously supplemented into the water tank to maintain the liquid level and absorption capacity of the absorbent 201.

[0108] The water outlet hole 205 is located at the lower part of the water tank and is used to discharge the absorbent that has absorbed ammonia gas out of the water tank. In order to save water and prevent pollution, the discharged ammonia-containing water is not directly discharged, but is introduced into the ballast tank of the ship. The ballast tank is a special cabin on the ship for loading ballast water. By adjusting the volume of the ballast water, the draft and stability of the ship can be changed. Storing the ammonia-containing water as ballast water in the ballast tank can reduce the risk of ammonia-containing water discharge on the one hand, and can also use the alkalinity of the ammonia-containing water to inhibit the growth of microorganisms in the ballast tank, thereby playing a certain anti-pollution role.

[0109] Through the setting of the water inlet hole 204 and the water outlet hole 205, the absorbent 201 in the ammonia gas absorption tank 200 can realize continuous or periodic updating and recycling. During operation, the updating frequency and updating amount of the absorbent can be reasonably controlled according to the ammonia absorption amount, the saturation degree of the absorbent and other parameters, so as to ensure that there is always enough fresh absorbent in the water tank to maintain the absorption efficiency, and to avoid excessive updating and waste of water resources. At the same time, reasonable use of ship resources such as fresh water tank and ballast tank can maximize the cascade utilization and recycling of water resources, and improve the economy and environmental protection of the system.

[0110] Optionally, the toxic ammonia release source 100 is selected from the group consisting of a catch pan 101, an ammonia fuel tank pressure relief valve 102, a double-walled pipe ammonia vent 103, a vented mast water spray system wastewater 104, and an ammonia-containing fuel confined space 105.

[0111] Further, in a liquid ammonia fuel vessel, there are multiple potential sources of toxic ammonia release 100, as shown in FIG. 1, including but not limited to:

[0112] Catch pan 101: During storage, transportation, and use of liquid ammonia fuel, there can be drips or spills. A catch pan 101 is usually installed below the equipment such as tanks, pipes, and valves to collect the leaked liquid ammonia. The liquid ammonia collected in the catch pan 101 will continue to evaporate, generating high concentrations of ammonia gas, which needs to be treated in time.

[0113] Ammonia fuel tank pressure relief valve 102: There is a certain pressure inside the liquid ammonia storage tank. When the pressure exceeds the safety threshold, the pressure relief valve 102 will automatically open to release the ammonia gas in the tank to the atmosphere to ensure the safety of the storage tank. The ammonia gas released by the pressure relief valve 102 is highly concentrated and needs to be collected and treated.

[0114] Double-walled pipe ammonia vent 103: Liquid ammonia fuel pipelines use a double-walled structure, with the inner pipe used for transporting liquid ammonia and the outer pipe used for collecting ammonia gas generated when the inner pipe leaks. The annular space of the double-walled pipe needs to be provided with a vent 103 to guide the collected ammonia gas out. The ammonia gas released by the vent 103 also needs to be treated.

[0115] Vented mast water spray system wastewater 104: During the liquid ammonia fuel filling process, a large amount of volatile ammonia gas will be generated in the storage tank and pipeline. In order to prevent the spread of ammonia gas on the deck of the vessel, a water spray system is usually installed on the vented mast to absorb and dilute the ammonia gas with water. The ammonia-containing wastewater 104 produced by the spray system will cause pollution if directly discharged, so it needs to be collected and treated. As mentioned above, one optional way is to return the diluted ammonia gas through the ammonia gas discharge pipeline to the ammonia gas absorption tank 200, realizing the recycling of water. The returned ammonia-containing wastewater enters the water tank and mixes with the absorbent 201 in the tank, without affecting the normal operation of the water tank.

[0116] Ammonia-containing fuel confined space 105: On the vessel, some equipment or pipelines in the liquid ammonia fuel system are located in confined spaces, such as fuel preparation rooms, valve control rooms, etc. These confined spaces 105 may have ammonia leaks, leading to an increase in ammonia concentration, and the air in these areas needs to be collected and treated.

[0117] It should be noted that in actual application, according to the specific design and arrangement of the vessel, there can be other release sources, such as sampling points, analysis instrument exhaust ports, etc. As long as there is a possibility of ammonia leakage, it should be included in the treatment range of the ammonia absorption system.

[0118] Optionally, the liquid level switch 203 controls the liquid level of the absorbent 201 to ensure that the volume of the gas phase space 206 in the ammonia absorption tank 200 accounts for at least 20% of the total volume of the ammonia absorption tank 200.

[0119] Further, in the ammonia absorption tank 200 of the present application, the liquid level of the absorbent 201 in the tank can be reasonably controlled. On one hand, the absorbent 201 is the key medium for absorbing and neutralizing ammonia, and a too low liquid level will result in a decrease in absorption efficiency; on the other hand, there needs to be sufficient gas phase space 206 in the tank to accommodate the diffusion and residence of ammonia. Therefore, an optimal balance point needs to be found between the liquid level and the volume of the gas phase space.

[0120] In the present embodiment, the liquid level switch 203 is optionally used to automatically control the liquid level in the water tank, as shown in FIG. 1. Optionally, the liquid level switch 203 can be a common liquid level detection element such as a float type, a conductivity type, an ultrasonic type, etc., which will not be described here in detail. By monitoring the change in the water level in the tank in real time, the opening degree of the water inlet hole 204 and the water outlet hole 205 is controlled to achieve automatic adjustment of the liquid level of the absorbent 201.

[0121] In the present embodiment, the liquid level switch 203 is used to automatically control the liquid level in the water tank, as shown in FIG. 1. The liquid level switch 203 can use common detection technologies on the market, such as a float type, a conductivity type, an ultrasonic type, etc., to monitor and adjust the change in the water level in the tank in real time. Since the liquid level switch itself is prior art, and its specific working principle and types are widely known in the technical field, it will not be described here in detail. This configuration allows automatic adjustment of the liquid level of the absorbent 201 by controlling the opening degree of the water inlet hole 204 and the water outlet hole 205, ensuring efficient operation of the system.

[0122] More specifically, when the water level in the tank decreases to a set lower limit, the liquid level switch 203 opens the water inlet hole 204 to supply water to the tank; when the water level rises to a set upper limit, the liquid level switch 203 closes the water inlet hole 204 to stop water supply. At the same time, the liquid level switch 203 can also control the opening degree of the water outlet hole 205, which is opened to discharge part of the absorbent when the water level is too high until the water level decreases to an appropriate range.

[0123] In the present embodiment, the liquid level of the absorbent in the water tank is optionally controlled within a specific range: to ensure that the volume of the gas phase space 206 in the ammonia absorption tank 200 accounts for at least 20% of the total volume of the water tank.

[0124] This control index is set based on the following considerations:

[0125] If the gas phase space 206 is too small, it will limit the diffusion and residence time of ammonia gas in the tank, reduce the full contact of ammonia gas with the absorbent 201, and affect the absorption effect.

[0126] If the gas phase space 206 is too large, it will occupy the effective volume of the water tank, reduce the absorption load of the absorbent 201, and reduce the space utilization rate of the water tank.

[0127] The 20% gas phase space volume ratio can meet the needs of ammonia gas diffusion and absorption, and can ensure the processing capacity and economy of the water tank.

[0128] It should be pointed out that in actual design, the specific volume ratio of the gas phase space 206 can be optimized and adjusted according to factors such as the shape, size, material of the ammonia gas absorption tank 200, etc., to achieve the best absorption effect and cost benefit.

[0129] It should be pointed out that in the above embodiments, there is no moving equipment, almost no maintenance after installation, only liquid level and pressure control is needed, and automatic control can be realized; the mechanical structure in the ammonia gas absorption tank 200 is simple, and the packing layer installation also does not need to be replaced, so the equipment cost and operation cost are relatively low.

[0130] It should be pointed out that in the embodiments of the present application, the liquid level switch 203 can be realized by adding a control valve at the water inlet or water outlet to realize liquid level control.

[0131] The optional absorbent can be water, sodium hydroxide solution, etc., at this time these absorbents cannot be connected with the fresh water tank and the ballast tank.

[0132] Optionally, the ammonia gas absorption tank 200 can be selected as a vertical container, so that the arrangement of the absorption tank can be reasonably optimized according to the area of the ship cabin.

[0133] Working principle:

[0134] The working principle of the toxic ammonia gas absorption system for liquid ammonia fuel ship of the present embodiment is as follows:

[0135] Collecting ammonia gas: the toxic ammonia gas release source 100 collects liquid and gaseous ammonia gas that may leak from various parts of the liquid ammonia fuel system of the ship, mainly including the receiving disc 101, the liquid ammonia fuel tank pressure relief valve 102, the ammonia gas discharge port of the double-wall pipe 103, the waste water of the water spray system of the air permeable mast 104, and the enclosed place containing ammonia gas fuel 105, etc.

[0136] Guiding ammonia gas: the ammonia gas guiding pipeline introduces the collected ammonia gas into the ammonia gas absorption tank 200. The gas phase ammonia discharge pipeline 301 guides gaseous ammonia gas, and a multi-hole nozzle 304 is arranged at the end of the pipeline to disperse the ammonia gas into small bubbles. The liquid phase ammonia discharge pipeline 302 guides liquid ammonia gas. Both pipelines are connected to a position below the gas diffusion layer 202 in the water tank.

[0137] Ammonia absorption: After ammonia enters the absorption tank, it rises in the absorbent 201, passes through the gas diffusion layer 202 of the multi-layer stainless steel mesh structure, and is fully dispersed and contacted with water to generate ammonia water through chemical absorption reaction. The diffusion layer prolongs the residence time of ammonia in water and improves the absorption efficiency.

[0138] Liquid level control: The liquid level switch 203 monitors the water level in the tank, and by controlling the opening and closing of the water inlet 204 and water outlet 205, it ensures that there is always enough absorbent 201 in the tank for ammonia absorption, and a certain amount of gas phase space 206 is left. Fresh water is supplied from the fresh water tank, and ammonia water is discharged into the ballast tank through the water outlet, realizing the cascade utilization of water.

[0139] Discharge of residual ammonia: After being absorbed, the slowly released ammonia gas enters the gas phase space at the top of the tank and is discharged through the ammonia discharge pipeline 401 and 402 after dilution. The water spray system 403 at the end of the pipeline further dilutes the ammonia concentration to a safe level. The spray water is returned to the absorption tank through the pipeline and discharged into the ballast tank together with the ammonia water.

[0140] In summary, through the key design of ammonia absorption tank, gas diffusion layer, liquid level control, ammonia discharge pipeline, etc., the system efficiently absorbs the toxic ammonia gas leaked from the ship's liquid ammonia fuel system, significantly improving the safety, environmental protection and economy of the ship using ammonia fuel. After ammonia enters the absorption tank, it is converted into ammonia water through sufficient contact with water, and a small amount of residual ammonia gas is discharged up to standard, realizing the cascade utilization and recycling of water resources.

[0141] The advantages of the above embodiments are as follows:

[0142] 1) Significantly improve the safety of the ship using ammonia fuel. The system effectively collects and absorbs the toxic ammonia gas leaked by accident through the setting of ammonia absorption tank and related guiding and discharge pipeline. The ammonia gas concentration in the environment can be quickly reduced to a safe range through the absorption and neutralization reaction of water on ammonia, avoiding poisoning of personnel and damage to equipment, thereby enhancing the overall safety of the ship.

[0143] 2) Improve the efficiency of ammonia treatment and reduce emissions. The gas diffusion layer in the ammonia absorption tank, combined with the multi-hole nozzle at the end of the gas phase ammonia discharge pipeline, strengthens the full contact and mass transfer of ammonia and water, improving the absorption efficiency. At the same time, by maintaining the gas-liquid contact area in the water tank, the water tank volume is reduced. After treatment, most of the ammonia gas is converted into ammonium hydroxide solution, and the slowly released ammonia gas after absorption is discharged to a safe area through the discharge pipeline, minimizing the release of toxic ammonia.

[0144] 3) System connection flexibility, strong adaptability. The system can be flexibly connected to potential ammonia leakage sources such as pipelines, valves, storage tanks, etc. according to the ship layout, ensuring comprehensive coverage and rapid response. The system design is compatible with the existing structure and operation process of the ship, and can be applied to various types and sizes of ships. In addition, the modular design of the system allows it to be adjusted according to different ship sizes and needs, providing highly customized solutions.

[0145] 4) Easy operation and maintenance, low cost. Compared with other ammonia treatment technologies, the system has simple equipment structure and can realize automatic control. When leakage occurs, it can be quickly started, and only needs to be regularly replenished and maintained during normal times. The operation is simple and reliable. The water tank design takes into account water recycling and wastewater treatment, and the water source can use the existing fresh water system, seawater system or other water sources on the ship, which is economical and practical.

[0146] 5) Significant environmental benefits. Through chemical neutralization reaction, ammonia is converted into ammonium hydroxide, not only reducing the harm of toxic ammonia emissions to the environment, but also supporting the International Maritime Organization's goal of achieving net zero greenhouse gas emissions in the shipping industry by 2050, which is of great significance to environmental protection.

[0147] In summary, the above-mentioned example provides a liquid ammonia fuel ship toxic ammonia absorption system that is safe, reliable, efficient, environmentally friendly, easy to operate and maintain, and highly adaptable, which can effectively control the risk of ammonia fuel leakage and promote the safe application of ammonia fuel in the shipping industry, providing important support for the sustainable development of the shipping industry, and has broad application prospects.

[0148] In order to better understand the technical solutions of the present application, a specific example will be described below, which mainly lists the details for the purpose of understanding, and does not limit the scope of protection of the present application.

[0149] In general, the example proposes a toxic ammonia absorption system for a liquid ammonia fuel ship, which includes an ammonia absorption tank 200, an ammonia guiding pipeline connecting the toxic ammonia release source 100 and the ammonia absorption tank 200, and a diluted ammonia release pipeline.

[0150] The example covers the main sources of ammonia leakage in the fuel filling and supply system on the ship, including but not limited to: receiving disc 101, liquid ammonia fuel tank pressure relief valve 102, double-wall pipe ammonia release port 103, water spray system 403 waste water 105, and enclosed places containing ammonia fuel (including fuel filling station, fuel tank joint place and fuel preparation room).

[0151] In this example, the ammonia absorption tank 200 is a liquid container, and its capacity is designed according to the actual needs of the ship. The liquid level in the tank is controlled by the liquid level switch 203 to ensure that there is enough gas space 206 in the tank. The absorbent in the freshwater tank will be introduced into the ammonia absorption tank 200 from the water inlet hole 204, and the absorbent 201 in the ammonia absorption tank 200 that has absorbed ammonia will be discharged to the pre-set position of the downstream ballast tank through the water outlet hole 205.

[0152] A gas diffusion layer 202 is provided in the ammonia absorption tank 200, and the diffusion layer 202 is firmly connected to the tank body around. After all the liquid and gas phase ammonia is introduced into the ammonia absorption tank 200, it is introduced below the gas diffusion layer 202, forcing the ammonia to pass through the diffusion layer 202 during the floating process in the absorbent 201, so that the ammonia can fully contact and react with the absorbent 201 in the tank.

[0153] The ammonia guiding pipeline connecting the toxic ammonia release source 100 and the ammonia absorption tank 200 includes a gas phase ammonia discharge pipeline 301 and a liquid phase ammonia discharge pipeline 302. One end of the gas phase ammonia discharge pipeline 301 and the liquid phase ammonia discharge pipeline 302 is connected to one of the toxic ammonia release source 100, and the other end is connected to the gas diffusion layer 202 below in the ammonia absorption tank 200. Among them, the end of the gas phase ammonia discharge pipeline 301 is provided with a nozzle 304.

[0154] In this example, a nozzle 304 is provided at the end of the gas phase ammonia discharge pipeline 301, which provides multiple outlets for ammonia, facilitating the diffusion of ammonia in water and the full chemical reaction with water.

[0155] In this example, a diluted ammonia discharge pipeline is provided, which includes a gas permeable pipe 401 and a gas permeable mast 402. One end of the gas permeable pipe 401 is connected to the gas phase space 206 of the ammonia absorption tank, and the other end is connected to the gas permeable mast 402. The ammonia slowly released by the absorbent 201 in the gas phase space 206 can enter the gas permeable mast 402 through the gas permeable pipe 401. A water spraying system 403 is provided at the end of the gas permeable mast 402. If the ammonia concentration in the gas permeable mast 402 does not meet the specification requirements, the water spraying system 403 will further neutralize the ammonia concentration to meet the specification requirements. The waste water generated by the water spraying system 403 is connected to the ammonia absorption tank 200 through the liquid phase ammonia discharge pipeline 302.

[0156] The beneficial effects of this example are that by providing the ammonia absorption tank 200 and the related guiding and discharge pipelines, the harmful ammonia is effectively collected and absorbed. After passing through the ammonia absorption tank 200, the liquid and gas phase ammonia concentration can be greatly reduced, and it can be safely and efficiently discharged. This system improves the safety of the ammonia fuel system on the ship and reduces the manufacturing cost and maintenance difficulty of the ship.

[0157] More specifically, in this example, the toxic ammonia release source 100 includes a receiving tray 101, a liquid ammonia tank pressure relief valve 102, a double-walled pipe ammonia vent 103, a vented mast water spray system 403, and a confined space containing ammonia fuel (including fuel filling stations, fuel tank connection points, and fuel preparation rooms).

[0158] The ammonia absorption tank 200 includes an absorption agent 201 inside the tank, a gas diffusion layer 202, a liquid level switch 203, a water inlet hole 204, and a water outlet hole 205.

[0159] The ammonia guiding pipeline includes a gas phase ammonia discharge pipeline 301, a liquid phase ammonia discharge pipeline 302, a check valve 303, and a nozzle 304. The guiding pipeline is arranged between the toxic ammonia release source 100 and the ammonia absorption tank. One end of the gas phase ammonia discharge pipeline 301 and the liquid phase ammonia discharge pipeline 302 is connected to one of the toxic ammonia release sources 100, and the other end is connected to the gas diffusion layer 202 below the ammonia absorption tank 200. The end of the gas phase ammonia discharge pipeline 301 is provided with a nozzle 304.

[0160] The diluted ammonia discharge pipeline includes a vent pipe 401, a vented mast 402, and a water spray system 403. One end of the vent pipe 401 is connected to the gas phase space 206 of the ammonia absorption tank 200, and the other end is connected to the vented mast 402.

[0161] Optionally, the toxic ammonia release source 100 covers the main sources of ammonia leakage in the fuel filling and supply system on the ship, including the receiving tray 101, the liquid ammonia tank pressure relief valve 102, the double-walled pipe ammonia vent 103, the vented mast water spray system 403, and the confined space containing ammonia fuel.

[0162] Optionally, the ammonia absorption tank 200 is arranged to absorb the released toxic ammonia. The absorption agent 201 is injected into the tank, and the liquid level in the tank is controlled by the liquid level switch 203 to ensure sufficient gas phase space 206. The water inlet hole 204 and the water outlet hole 205 are used for the update of the absorption agent 201 in the tank. The water source of the water inlet hole 204 is the fresh water tank, and the downstream of the water outlet hole 205 is the ballast tank. The gas diffusion layer 202 is arranged inside the ammonia absorption tank 200 to ensure sufficient contact between ammonia and water, and to promote chemical reaction.

[0163] Optionally, the gas diffusion layer 202 is a multi-layer stainless steel mesh, which is used to promote the contact between gas and water, and to facilitate the chemical reaction between ammonia and water.

[0164] Optionally, the nozzle 304 is arranged at the end of the gas phase ammonia discharge pipeline 301. The nozzle 304 provides multiple (more than 2) outlets for ammonia, which facilitates the diffusion of ammonia in water.

[0165] Optionally, a water spray system 403 is arranged in the air breather mast 402, and the waste water generated by the system is connected to the ammonia absorption tank 200 through the liquid phase ammonia discharge pipeline 302.

[0166] The specific details involved in the present example are further explained below.

[0167] The present example is provided with an ammonia absorption tank 200 in the shape of a cuboid in the side cabin of the ship, with a capacity of 100 cubic meters. It should be noted that the position of the ammonia absorption tank 200 can be flexibly arranged according to the specific circumstances of the ship, such as above the deck or in other cabins, empty cabins.

[0168] The toxic ammonia absorption system for the liquid ammonia fuel ship of the present example is provided with a gas phase ammonia discharge pipeline 301 connecting the ammonia absorption tank 200 and the gas phase toxic ammonia source, which includes the liquid ammonia fuel tank pressure relief valve 102, the double-wall pipe ammonia discharge port 103, and the enclosed place containing ammonia gas fuel (such as the fuel filling station, the fuel tank joint place, and the fuel preparation room). When the gas phase ammonia discharge pipeline 301 passes through the cabin that needs to use the double-wall pipe, the double-wall pipe should be used. A multi-outlet nozzle 304 is arranged at the end of the gas phase ammonia discharge pipeline 301 below the gas diffusion layer 202. More specifically, six outlet channels are arranged in the present example. It should be noted that the specific number can be adjusted according to the needs of the ship to ensure that the ammonia gas is effectively diffused into the absorbent 201.

[0169] The present example is also provided with a liquid phase ammonia discharge pipeline 302 connecting the ammonia absorption tank 200 and the liquid phase ammonia discharge pipeline 302, such as the receiving disc 101 and the waste water 105 of the air breather mast water spray system 403. The liquid phase ammonia discharge pipeline 302 is connected to the absorbent 201 in the ammonia absorption tank 200, and the end of the liquid phase ammonia discharge pipeline 302 is located below the gas diffusion layer 202.

[0170] The gas diffusion layer 202 is arranged inside the ammonia absorption tank 200 and is composed of multiple layers of stainless steel wire mesh. The mesh size should ensure that the ammonia gas is efficiently diffused into the absorbent 201. The gas diffusion layer 202 is firmly connected to the absorption tank through positioning buckles around it. It should be noted that in other embodiments of the present application, the specific fixing method can be flexibly designed, such as arranging supports at the bottom of the tank to connect the diffusion layer 202.

[0171] The absorbent 201 in the freshwater tank is introduced into the ammonia absorption tank 200 through the water inlet hole 204, and the absorbent 201 that has absorbed ammonia gas is discharged to the pre-set position of the downstream ballast tank through the water outlet hole 205. The liquid level switch 203 is arranged in the ammonia absorption tank 200 to control the liquid level height inside the ammonia absorption tank 200, ensuring that there is enough gas phase space 206.

[0172] The example sets a gas permeation pipe 401, one end of which is connected to the gas phase space 206 of the absorption tank, and the other end of which is connected to a gas permeation mast 402. Ammonia gas slowly released after being absorbed by the absorbent 201 enters the gas permeation mast 402 through the gas permeation pipe 401, and the gas permeation mast 402 is provided with a water spraying system 403 at the end thereof. When the ammonia gas concentration in the gas permeation mast 402 exceeds the standard, the water spraying system 403 is opened to further dilute the ammonia gas concentration to the standard requirement. Optionally, the waste water generated by the water spraying system 403 is discharged through the liquid phase ammonia discharge pipeline 302 or is returned to the ammonia gas absorption tank 200.

[0173] It should be noted that all documents referred to in this application are incorporated by reference into this application as if each document were individually incorporated. In addition, it should be understood that various changes and modifications can be made to this application by those skilled in the art as a result of reading the above description of the preferred embodiments, and it is intended to embrace all such changes and modifications in the scope of the appended claims.

[0174] Also, the recitation of "first" and "second" elements does not imply any particular order, but is used to distinguish one element from another. Furthermore, the use of the terms "including" and "including" or any other variation thereof is intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements recited, but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element preceded by "comprises a" does not exclude the existence of additional identical elements in the process, method, article, or apparatus that includes the recited element. In the claims and specification of this patent, if a statement refers to performing an act with a certain element, it means performing the act with at least that element, including two cases: performing the act with only that element, and performing the act with that element and other elements.

[0175] Although the present application has been illustrated and described with reference to certain preferred embodiments thereof, it should be understood by those skilled in the art that various changes in form and detail can be made therein without departing from the spirit and scope of the application.

Claims

1. A toxic ammonia gas absorption system for a liquid ammonia fuelled ship, characterised in that The application relates to a system for collecting and absorbing toxic ammonia gas, comprising: a toxic ammonia gas release source (100) for collecting ammonia gas leaked from a liquid ammonia fuel system of a ship; an ammonia gas absorption tank (200) provided with an absorbent (201) for absorbing the ammonia gas and a liquid level switch (203) for controlling the liquid level of the absorbent (201) so as to ensure that the ammonia gas absorption tank (200) has sufficient gas phase space (206), wherein a gas diffusion layer (202) is arranged in the ammonia gas absorption tank (200) and is arranged below the liquid level of the absorbent (201), and a temperature control device (207) is arranged in the ammonia gas absorption tank (200) for controlling the temperature in the tank; an ammonia gas guide pipeline connected at one end to the toxic ammonia gas release source (100) and at the other end to the ammonia gas absorption tank (200) and arranged below the gas diffusion layer (202), so that the ammonia gas collected by the toxic ammonia gas release source (100) must pass through the gas diffusion layer (202) during the floating process after being introduced into the absorbent (201) of the ammonia gas absorption tank (200); an ammonia gas discharge pipeline for discharging the ammonia gas slowly released from the absorbent (201) in the ammonia gas absorption tank (200) to the external environment.

2. The system of claim 1, wherein, The ammonia gas guide pipeline comprises a gas phase ammonia discharge pipeline (301) and a liquid phase ammonia discharge pipeline (302); the gas phase ammonia discharge pipeline (301) is provided at the tail end with a porous nozzle (304) for increasing the diffusion efficiency of the ammonia gas in the absorbent (201).

3. The system of claim 2, wherein, The porous nozzle (304) comprises a plurality of small holes uniformly distributed along the circumference of the nozzle, which are used for dispersing the ammonia gas in the ammonia gas guide pipeline into small bubbles so as to increase the contact area between the ammonia gas and the absorbent (201) and improve the ammonia gas absorption efficiency.

4. The system of claim 1, wherein, The gas diffusion layer (202) comprises a filler and is connected to the inner wall of the ammonia gas absorption tank (200) through a positioning buckle.

5. The system of claim 1, wherein, The ammonia gas discharge pipeline comprises a gas permeable pipe (401) and a gas permeable mast (402) connected in sequence, one end of the gas permeable pipe (401) is connected to the gas phase space (206) in the ammonia gas absorption tank (200), the other end of the gas permeable pipe (401) is connected to the gas permeable mast (402), which is used for guiding the ammonia gas slowly released from the absorbent (201) in the gas phase space (206) of the ammonia gas absorption tank (200) to the gas permeable mast (402) so as to be discharged into the atmosphere.

6. The system of claim 1, wherein, The ammonia gas absorption tank is provided with a temperature control device (207) for adjusting the liquid temperature after absorbing the ammonia gas so as to maintain a stable absorption rate.

7. The system of claim 5, wherein, The gas permeable mast (402) is provided at the tail end with an absorbent spraying system (403) for further neutralizing the concentration of the ammonia gas discharged from the ammonia gas absorption tank (200) into the gas permeable pipe (401), and the waste liquid generated by the absorbent spraying system (403) is returned to the ammonia gas absorption tank (200) through the ammonia gas discharge pipeline.

8. The system of claim 1, wherein, The ammonia absorption tank (200) is also provided with water inlet hole (204) and water outlet hole (205), for the circulation of the absorbent absorption (201) to maintain the absorption efficiency of ammonia.

9. The system of claim 8, wherein, The water source of the water inlet hole (204) is fresh water tank, and the downstream of the water outlet hole (205) is ballast tank.

10. The system of claim 1, wherein, The toxic ammonia release source (100) is selected from the group consisting of receiving disc (101), liquid ammonia fuel tank pressure relief valve (102), double wall pipe ammonia release port (103), air permeable mast water spray system waste water (104), and ammonia-containing fuel enclosed space (105).

11. The system of claim 1, wherein, The liquid level switch (203) controls the liquid level of the absorbent (201) to ensure that the volume of the gas phase space (206) in the ammonia absorption tank (200) is at least 20% of the total volume of the ammonia absorption tank (200).

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