Marine ammonia gas treatment and exhaust gas decarbonization system

Abstract

A marine ammonia gas treatment and exhaust gas decarbonization system, comprising an engine (10), a denitration device (20), an exhaust pipe (30), a carbon dioxide separation device (40) and a urea generation device (50); the engine (10) has a fuel gas mode fueled by ammonia and a fuel oil mode fueled by fossil fuel oil; an inlet of the denitration device (20) is connected to an exhaust outlet of the engine (10), and the denitration device (20) is arranged on the exhaust pipe (30) close to the engine; a first outlet of the exhaust pipe (30) is in communication with the external air, a second outlet of the exhaust pipe (30) is connected to the carbon dioxide separation device (40) by means of an exhaust fan (410), and a first outlet of the carbon dioxide separation device (40) is connected to the urea generation device (50). Ammonia gas is treated in the fuel gas mode or during switching of the fuel gas mode and the fuel oil mode, and decarbonization treatment is performed in the fuel oil mode or when other fuel oil devices, such as diesel generators, are used while nitrogen oxides in exhaust gas are treated, thereby improving the environmental protection performance of ships, reducing greenhouse gas emissions, reducing costs by means of resource recycling, and achieving dual improvements in environmental protection and economic benefits.

Description

A marine ammonia treatment and exhaust gas decarbonization system Technical Field

[0001] This invention relates to the field of marine exhaust gas treatment technology, specifically to a marine ammonia treatment and exhaust gas decarbonization system. Background Technology

[0002] As global climate change intensifies, the International Maritime Organization (IMO) adopted a new strategy for reducing greenhouse gas (GHG) emissions from ships at its MEPC80 meeting in 2023. This strategy aims to further tighten greenhouse gas emission standards and sets a target of achieving net-zero emissions by around 2050. To achieve this ambitious goal, ship propulsion systems are gradually shifting towards low-carbon or even zero-carbon fuels to reduce their environmental impact.

[0003] Among numerous potential alternative fuels, ammonia is considered a promising clean fuel due to its carbon-free chemical composition and lack of carbon dioxide production during combustion. Furthermore, ammonia liquefies at -33°C under normal pressure, making its storage and transportation relatively convenient and cost-effective. However, the toxicity of ammonia is a significant factor that must be considered when using it as a marine fuel. The International Association of Classification Societies (IACS) has imposed stringent safety requirements on ammonia releases, particularly in areas where personnel may be affected, stipulating that ammonia emission concentrations must not exceed 25 ppm. This requirement necessitates appropriate treatment of ammonia before its release by ships to ensure compliance with safety standards and mitigate toxic effects.

[0004] Current ammonia-fueled engines are typically designed as dual-fuel systems, meaning that in fuel mode, the engine still needs to burn fossil fuels. In addition, ships are generally equipped with diesel generators that use fossil fuels. To reduce carbon emissions from these devices during operation, ships usually need to be equipped with additional carbon aftertreatment systems to meet current carbon emission standards.

[0005] Despite its numerous advantages as a clean fuel, ammonia's application in ships still faces several challenges. Existing ammonia processing technologies, such as ammonia absorption, require significant processing and storage space, potentially adding complexity to ship design and operation. Furthermore, existing carbon aftertreatment systems may not meet future, more stringent emission requirements and may be limited by efficiency and cost constraints.

[0006] Therefore, in order to design a system that can effectively treat ammonia emissions and efficiently remove harmful substances from exhaust gas, this application provides a marine ammonia treatment and exhaust gas decarbonization system. Summary of the Invention

[0007] In view of the defects and deficiencies of existing ammonia treatment and exhaust gas decarbonization technologies, this application provides a marine ammonia treatment and exhaust gas decarbonization system. This marine ammonia treatment and exhaust gas decarbonization system, by incorporating a denitrification device, a carbon dioxide separation device, and a urea generation device, can be optimized for different operating conditions. It treats ammonia during gas or gas / fuel mode switching (purge); performs decarbonization treatment during fuel mode or other fuel systems (such as diesel generators); and treats nitrogen oxides (NOx) in the exhaust gas during gas / fuel mode or other fuel systems. This marine ammonia treatment and exhaust gas decarbonization system not only improves the environmental performance of ships and reduces greenhouse gas emissions, but also reduces operating costs through resource recycling, achieving a dual improvement in environmental and economic benefits.

[0008] One embodiment of this application provides a marine ammonia treatment and exhaust gas decarbonization system, comprising at least:

[0009] A low-pressure pump unit, the low-pressure pump unit including a first low-pressure pump and a second low-pressure pump, the first low-pressure pump and the second low-pressure pump being redundant to each other;

[0010] A high-pressure supply unit, comprising a first high-pressure fuel pump, a second high-pressure fuel pump, and a heat exchanger, wherein the first high-pressure fuel pump and the second high-pressure fuel pump are redundant to each other, and the outlet of the first high-pressure fuel pump or the outlet of the second high-pressure pump is connected to the inlet of the heat exchanger.

[0011] The fuel assembly unit includes a supply valve assembly unit and a return valve assembly unit.

[0012] A high-pressure pump unit, comprising a first high-pressure pump and a second high-pressure pump, wherein the first high-pressure pump and the second high-pressure pump are redundant to each other;

[0013] Ammonia evaporator;

[0014] An engine, comprising a gas combustion mode and a fuel oil mode, wherein the gas combustion mode uses ammonia as fuel; and the fuel oil mode uses fossil fuel as fuel; the ammonia fuel outlet of the engine is connected to the inlet of the return valve assembly unit, and the first outlet of the return valve assembly unit is connected to a pipeline between the outlet of the low-pressure pump unit and the inlet of the high-pressure supply unit.

[0015] A denitrification device, wherein the inlet of the denitrification device is connected to the exhaust outlet of the engine;

[0016] An exhaust pipe, wherein the inlet of the exhaust pipe is connected to the outlet of the denitrification device, and the first outlet of the exhaust pipe is connected to the outside;

[0017] A carbon dioxide separation device, wherein the inlet of the carbon dioxide separation device is connected to the second outlet of the exhaust pipe via an exhaust fan;

[0018] The urea generating unit has a first outlet connected to the carbon dioxide separation unit; the outlet of the urea generating unit is connected to a urea solution tank, and a level gauge is installed inside the urea generating unit; a first control valve is installed between the urea generating unit and the urea solution tank; the first outlet of the urea solution tank is connected to the denitrification unit through a urea treatment device to provide the denitrification unit with the reducing agent urea; and the second outlet of the urea solution tank is connected to a urea powder generating unit.

[0019] The liquid ammonia storage tank has its outlet connected in sequence to the ammonia fuel inlet of the engine via the low-pressure pump unit, the high-pressure supply unit, and the liquid supply valve group unit; or, the outlet of the liquid ammonia storage tank is connected in sequence to the low-pressure pump unit, the high-pressure pump unit, and the ammonia evaporator, with the first outlet of the ammonia evaporator connected to the urea generating device to supply ammonia to the urea generating device; and the second outlet of the ammonia evaporator connected to the denitrification device to supply ammonia to the denitrification device.

[0020] In one embodiment, an ammonia buffer tank is provided between the second outlet of the ammonia evaporator and the denitrification device, and a second control valve is provided between the ammonia buffer tank and the denitrification device.

[0021] In one embodiment, the marine ammonia treatment and exhaust gas decarbonization system also includes a liquid ammonia buffer tank. The second outlet of the return valve assembly unit is connected to the inlet of the liquid ammonia buffer tank, and the outlet of the liquid ammonia buffer tank is connected to the pipeline between the outlet of the low-pressure pump unit and the inlet of the high-pressure supply unit.

[0022] In one embodiment, the marine ammonia treatment and exhaust gas decarbonization system further includes an ammonia capture tank and a gas-liquid buffer tank. The inlet of the gas-liquid buffer tank is connected to the ammonia fuel outlet of the engine and the inlet of the return valve assembly unit via a pipeline. The gas-liquid buffer tank, the high-pressure supply unit, and the liquid ammonia buffer tank are vented to the ammonia capture tank.

[0023] In one embodiment, the marine ammonia treatment and exhaust gas decarbonization system further includes an ammonia liquefaction device. The pipeline between the outlet of the low-pressure pump unit and the inlet of the high-pressure supply unit is connected to the ammonia liquefaction device via a spray pipe. The inlet of the ammonia liquefaction device is connected to an ammonia interface. The bottom outlet of the ammonia liquefaction device is connected to the inlet of the low-pressure pump unit.

[0024] In one embodiment, the ammonia liquefaction device includes an outlet pipe located at its top, the outlet of which is connected to the outside, and an ammonia concentration detector is installed on the outlet pipe.

[0025] In one embodiment, the first outlet of the ammonia capture tank is connected to the ammonia liquefaction device through the ammonia interface; the second outlet of the ammonia capture tank is connected to the inlet of the ammonia buffer tank through the ammonia compressor.

[0026] In one embodiment, unreacted ammonia and unreacted carbon dioxide in the urea generating device are passed sequentially through an ammonia-carbon dioxide buffer tank and an ammonia-carbon dioxide separator.

[0027] The carbon dioxide separated by the ammonia-carbon dioxide separation device enters the urea generation device after passing through a carbon dioxide compressor.

[0028] The ammonia separated by the ammonia-carbon dioxide separation device enters the urea generation device after passing through the ammonia compressor; or, the ammonia separated by the ammonia-carbon dioxide separation device enters the ammonia liquefaction device through the ammonia interface.

[0029] In one embodiment, the second outlet of the carbon dioxide separator is connected to the inlet of the nitrogen separator, and the exhaust outlet of the nitrogen separator is connected to the first outlet of the exhaust pipe.

[0030] In one embodiment, the nitrogen outlet of the nitrogen separation device is connected to a nitrogen cylinder group via a nitrogen compressor.

[0031] In one implementation, the ammonia cylinder group is connected to the outlet of the liquid supply valve group unit and the inlet of the engine via a nitrogen port.

[0032] In one embodiment, a carbon dioxide compressor is provided between the first outlet of the carbon dioxide separation device and the urea generation device.

[0033] As described above, the marine ammonia treatment and exhaust gas decarbonization system of this application has the following beneficial effects:

[0034] The marine ammonia treatment and exhaust gas decarbonization system disclosed in this application, by incorporating a denitrification device, a carbon dioxide separation device, and a urea generation device, can be optimized for different operating conditions. During gas or gas / fuel mode switching (purge), it treats ammonia by liquefying it for reuse, or uses it as a supplementary reducing agent for the denitrification device to reduce emissions and environmental impact. In fuel mode or other fuel-powered systems (such as diesel generators), it performs decarbonization by reacting ammonia and carbon dioxide to generate urea, thus reducing carbon dioxide emissions and meeting current and future stringent environmental requirements. The chemical reaction during urea generation effectively fixes and utilizes carbon dioxide. In gas / fuel mode or other fuel-powered systems (such as diesel generators), it treats nitrogen oxides (NOx) in the exhaust gas, improving the ship's environmental performance. This marine ammonia treatment and exhaust gas decarbonization system not only improves the ship's environmental performance and reduces greenhouse gas emissions but also reduces operating costs through resource recycling, achieving a dual improvement in environmental and economic benefits. This contributes to promoting the green transformation and sustainable development of ship propulsion systems. Attached Figure Description

[0035] Figure 1 shows a schematic diagram of the marine ammonia treatment and exhaust gas decarbonization system according to an embodiment of the present invention.

[0036] Figure 2 shows a schematic diagram of the post-treatment structure of the ammonia capture tank and the ammonia-carbon dioxide separation device in the marine ammonia treatment and tail gas decarbonization system of an embodiment of the present invention.

[0037] Figure 3 shows a schematic diagram of the connection between the urea treatment device, the denitrification device, and the urea powder generation device in the marine ammonia treatment and exhaust gas decarbonization system of an embodiment of the present invention.

[0038] Figure 4 shows a schematic diagram of the post-treatment structure of the nitrogen separation device in the marine ammonia treatment and tail gas decarbonization system according to an embodiment of the present invention.

[0039] Component Numbering Explanation: 1. Liquid Ammonia Storage Tank; 2. Low-Pressure Pump Unit; 21. First Low-Pressure Pump; 22. Second Low-Pressure Pump; 3. High-Pressure Supply Unit; 31. First High-Pressure Fuel Pump; 32. Second High-Pressure Fuel Pump; 33. Heat Exchanger; 4. Fuel Valve Assembly Unit; 41. Liquid Supply Valve Assembly Unit; 42. Liquid Return Valve Assembly Unit; 5. High-Pressure Pump Unit; 51. First High-Pressure Pump; 52. Second High-Pressure Pump; 6. Ammonia Evaporator; 7. Liquid Ammonia Buffer Tank; 8. Gas-Liquid Buffer Tank; 9. Ammonia Capture Tank; 10. Engine; 20. Denitrification Device; 30. Exhaust Pipe; 40. Carbon Dioxide Separator; 410. Exhaust Fan; 420. Carbon Dioxide Compressor; 50. Urea Generating Device; 510. Level Gauge; 520. First Control Valve; 530. Urea Solution Tank; 540. Urea Treatment Device; 550. Urea Powder Generating Device. 60, Ammonia-carbon dioxide buffer tank; 61, Ammonia buffer tank; 62, Second control valve; 70, Ammonia-carbon dioxide separation device; 71, Ammonia compressor; 80, Nitrogen separation device; 81, Nitrogen compressor; 82, Nitrogen cylinder group; 90, Ammonia liquefaction device; 91, Outlet pipeline; 92, Ammonia concentration detector. Detailed Implementation

[0040] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0041] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0042] With increasing global concern about climate change, the International Maritime Organization (IMO) adopted a new strategy for reducing greenhouse gas (GHG) emissions from ships at the MEPC80 meeting in 2023, aiming to achieve net-zero emissions by around 2050. In response to this strategy, ship propulsion systems are gradually transitioning to low-carbon or zero-carbon fuels, with ammonia receiving widespread attention as a potential clean fuel. Ammonia not only contains no carbon in its chemical composition and produces no carbon dioxide as a fuel product, but it is also easily liquefied at normal pressure, offering advantages such as convenient storage and transportation and low cost.

[0043] However, using ammonia as a marine fuel also presents several challenges. First, ammonia is toxic, posing a threat to human health and environmental safety. The International Association of Classification Societies (IACS) has established stringent safety standards for ammonia emissions, requiring that ammonia concentrations not exceed 25 ppm in areas where personnel are affected. Furthermore, ammonia-fueled engines currently mostly employ a dual-fuel design, meaning they still burn fossil fuels in fuel oil mode, necessitating additional carbon emission aftertreatment devices to meet carbon emission standards.

[0044] Existing ammonia treatment technologies, such as ammonia absorption, typically require large processing and storage spaces, which can introduce additional complexity to ship design and operation. Furthermore, existing carbon aftertreatment facilities may not meet future, more stringent emission requirements and may be limited by efficiency and cost constraints.

[0045] To address the aforementioned deficiencies, this application provides a marine ammonia treatment and exhaust gas decarbonization system. The following embodiments will provide a detailed description.

[0046] This embodiment provides a marine ammonia treatment and exhaust gas decarbonization system, as shown in Figure 1. The marine ammonia treatment and exhaust gas decarbonization system includes an engine 10, a denitrification device 20, an exhaust pipe 30, a carbon dioxide separation device 40, and a urea generation device 50.

[0047] As shown in Figure 1, the engine 10 includes a gas combustion mode and a fuel combustion mode. The gas combustion mode uses ammonia as fuel, while the fuel combustion mode uses fossil fuels. An exhaust pipe 30 is installed at the exhaust outlet of the engine 10 (i.e., the outlet from which exhaust gases are emitted after fuel combustion). A denitrification device 20 is installed near the exhaust outlet of the engine 10 on the exhaust pipe 30. The denitrification device 20 is used to treat nitrogen oxides in the exhaust gas. The exhaust pipe 30 is the exhaust pipe of the engine 10. Depending on the actual system design and combination, it can also be other devices that burn ammonia or fuel oil. The exhaust pipe 30 has a first outlet and a second outlet. The first outlet of the exhaust pipe 30 is connected to the outside, and the second outlet of the exhaust pipe 30 is connected to the inlet of a carbon dioxide separator 40 through an exhaust fan 410. The carbon dioxide separator 40 is used to purify carbon dioxide in the exhaust gas, and the exhaust fan 410 is used to extract exhaust gas from the exhaust pipe 30. The first outlet of the carbon dioxide separation device 40 is connected to the urea generation device 50. The urea generation device 50 is used for the chemical reaction of ammonia and carbon dioxide. The chemical reaction formula of ammonia and carbon dioxide is: 2NH3 + CO2 = CO(NH2)2 + H2O. The reaction conditions are high temperature, high pressure and catalyst.

[0048] The marine ammonia treatment and exhaust gas decarbonization system of this embodiment, by setting up a denitrification device 20, a carbon dioxide separation device 40, and a urea generation device 50, can be optimized according to different operating conditions. It treats ammonia when switching between gas or gas / fuel modes (purge); performs decarbonization treatment when in fuel mode or other fuel devices (such as diesel generators); and treats nitrogen oxides (NOx) in exhaust gas when in gas / fuel mode or other fuel devices (such as diesel generators). This not only improves the environmental performance of the ship and reduces greenhouse gas emissions, but also reduces operating costs through resource recycling, achieving a dual improvement in environmental protection and economic benefits.

[0049] As shown in Figure 1, the marine ammonia treatment and exhaust gas decarbonization system also includes a liquid ammonia storage tank 1, a low-pressure pump unit 2, a high-pressure supply unit 3, a fuel valve group unit 4, a high-pressure pump unit 5, and an ammonia evaporator 6.

[0050] The low-pressure pump unit 2 includes a first low-pressure pump 21 and a second low-pressure pump 22. The first low-pressure pump 21 and the second low-pressure pump 22 are redundant to each other, that is, one low-pressure pump is used and the other is on standby. They are used to supply and output liquid ammonia in the liquid ammonia storage tank 1. They can be installed in the tank or installed independently.

[0051] The high-pressure supply unit 3 includes a first high-pressure fuel pump 31, a second high-pressure fuel pump 32, and a heat exchanger 33. The first high-pressure fuel pump 31 and the second high-pressure fuel pump 32 are redundant, that is, the first high-pressure fuel pump 31 and the second high-pressure fuel pump 32 are backups for each other. The inlet of the heat exchanger 33 is connected to either the outlet of the first high-pressure fuel pump 31 or the outlet of the second high-pressure fuel pump 32. The heat exchanger 33 and the first high-pressure fuel pump 31 or the second high-pressure fuel pump 32 work together to pressurize and heat the fuel (ammonia) to ensure that the pressure and temperature entering the engine 10 meet the requirements.

[0052] The fuel valve assembly unit 4 includes a liquid supply valve assembly unit 41 and a liquid return valve assembly unit 42, which are used for the isolation control of the engine 10 and the ammonia fuel supply system.

[0053] The high-pressure pump unit 5 includes a first high-pressure pump 51 and a second high-pressure pump 52. The first high-pressure pump 51 and the second high-pressure pump 52 are redundant to each other, that is, the first high-pressure pump 51 and the second high-pressure pump 52 are backups for each other, and are used to increase the pressure of liquid ammonia.

[0054] Ammonia evaporator 6 is used for the evaporation of liquid ammonia.

[0055] The outlet of the liquid ammonia storage tank 1 has two lines. The first line connects the outlet of the liquid ammonia storage tank 1 sequentially through the low-pressure pump unit 2, the high-pressure supply unit 3, and the liquid supply valve assembly unit 41 to the ammonia fuel inlet of the engine 10. The ammonia fuel outlet of the engine 10 is connected to the inlet of the return valve assembly unit 42, and the first outlet of the return valve assembly unit 42 is connected to the outlet of the low-pressure pump unit 2 and the inlet of the high-pressure supply unit 3 via a pipeline. The second line connects the outlet of the liquid ammonia storage tank 1 sequentially through the low-pressure pump unit 2, the high-pressure pump unit 5, and the ammonia evaporator 6. The first outlet of the ammonia evaporator 6 is connected to the urea generating unit 50 to supply ammonia to the urea generating unit 50; the second outlet of the ammonia evaporator 6 is connected to the denitrification unit 20 to supply ammonia to the denitrification unit 20.

[0056] The marine ammonia treatment and exhaust gas decarbonization system provided in this embodiment, in the gas combustion mode of engine 10, the liquid ammonia in the liquid ammonia storage tank 1 sequentially passes through the low-pressure pump unit 2, the high-pressure supply unit 3, and the liquid supply valve group unit 41 in the fuel valve group unit 4, supplying ammonia fuel that meets the pressure and temperature requirements to engine 10 for use. Unburned liquid ammonia flows back to the high-pressure supply unit 3 through the liquid return valve group unit 42 in the fuel valve group unit 4, and is supplied to engine 10 again for reuse. Another path of liquid ammonia after passing through the low-pressure pump unit 2 is sent to the high-pressure pump unit 5, and after being pressurized, it enters the ammonia evaporator 6, where the high-pressure liquid ammonia is evaporated into high-pressure ammonia gas. The heat source of the ammonia evaporator 6 can utilize the waste heat of the exhaust gas of engine 10 or marine steam, etc. Usually, in the gas combustion mode of engine 10, there may be incomplete combustion of ammonia gas, resulting in the presence of some ammonia gas in the exhaust gas. This part of ammonia gas can react with nitrogen oxides in the denitrification device 20 (the products are nitrogen gas and water). In gas combustion mode, the marine ammonia treatment and exhaust gas decarbonization system can liquefy ammonia, enabling its reuse, or use it as a supplementary reducing agent for the denitrification unit 20, thereby reducing ammonia emissions and minimizing environmental impact.

[0057] As shown in Figure 3, the outlet of the urea generating device 50 is connected to the urea solution tank 530, which is used to store urea solution. The first outlet of the urea solution tank 530 is connected to the denitrification device 20 through the urea treatment device 540, which is used to provide the denitrification device 20 with the reducing agent urea. In fuel mode, the reducing agent urea required for the reaction in the denitrification device 20 can come from the urea solution tank 530. After passing through the urea treatment device 540 (including a urea delivery pump, injection unit, etc., which are only simplified in the figure), the urea solution is injected into the denitrification device 20. The reaction products of the urea solution and nitrogen oxides contain carbon dioxide, which can be further processed by the above-mentioned decarbonization system to avoid the generated carbon dioxide affecting the carbon emission index.

[0058] The second outlet of the urea solution tank 530 is connected to the urea powder generating device 550, which evaporates and dehydrates the urea solution to form urea powder, thus reducing the storage space on board.

[0059] A level gauge 510 is installed inside the urea generating device 50, and a first control valve 520 is installed between the urea generating device 50 and the urea solution tank 530. When the liquid level in the urea generating device 50 reaches the specified liquid level value, the first control valve 520 opens, sending the urea solution to the urea solution tank 530.

[0060] In an optional embodiment, as shown in Figure 1, an ammonia buffer tank 61 is provided between the second outlet of the ammonia evaporator 6 and the denitrification device 20. A first control valve 62 is provided between the ammonia buffer tank 61 and the denitrification device 20. The ammonia buffer tank 61 is used for ammonia storage and pressure control. This circuit is used to replenish the ammonia in the denitrification device 20 in a timely manner when the ammonia in the denitrification device 20 is insufficient. The amount of ammonia can be controlled by the second control valve 62.

[0061] In an optional embodiment, as shown in Figure 1, the marine ammonia treatment and exhaust gas decarbonization system further includes a liquid ammonia buffer tank 7. The second outlet of the return valve group unit 42 in the fuel valve group unit 4 is connected to the inlet of the liquid ammonia buffer tank 7. The outlet of the liquid ammonia buffer tank 7 is connected to the outlet of the low-pressure pump unit 2 and the inlet of the high-pressure supply unit 3 via a pipeline. The liquid ammonia buffer tank 7 is used to temporarily store liquid ammonia returning from the engine 10 and to separate the gas and liquid. The separated liquid ammonia then flows back to the high-pressure supply unit 3 and is supplied to the engine 10 for reuse.

[0062] In an optional embodiment, as shown in Figure 1, the marine ammonia treatment and exhaust gas decarbonization system further includes an ammonia capture tank 9 and a gas-liquid buffer tank 8. The inlet of the gas-liquid buffer tank 8 is connected to the ammonia fuel outlet of the engine 10 and the inlet of the return valve group unit 42 in the fuel valve group unit 4 via a pipeline. The gas-liquid buffer tank 8, the high-pressure supply unit 3, and the liquid ammonia buffer tank 7 are vented to the ammonia capture tank 9, which is used for collecting ammonia from various locations. The gas-liquid buffer tank 8 is used for temporary storage of liquid ammonia during nitrogen purging. Since the ammonia fuel supply pipeline needs to be purged when the engine 10 switches from gas combustion mode to fuel combustion mode or other demand modes, as shown in Figure 1, a nitrogen interface is provided on the pipeline at the outlet end of the liquid supply valve group unit 41 of the fuel valve group unit 4. The nitrogen output through the nitrogen interface purges the liquid ammonia between the fuel valve group unit 4 and the engine 10 to the gas-liquid buffer tank 8. The gas-liquid buffer tank 8 contains liquid ammonia and nitrogen, and the liquid ammonia is vented to the ammonia capture tank 9.

[0063] In an optional embodiment, as shown in Figure 1, the marine ammonia treatment and exhaust gas decarbonization system further includes an ammonia liquefaction device 90. The ammonia liquefaction device 90 is used for ammonia liquefaction. The pipeline between the outlet of the low-pressure pump unit 2 and the inlet of the high-pressure supply unit 3 is connected to the ammonia liquefaction device 90 via a spray pipe. The inlet of the ammonia liquefaction device 90 is connected to an ammonia interface. The bottom outlet of the ammonia liquefaction device 90 is connected to the inlet of the low-pressure pump unit 2. Pressurized liquid ammonia from the low-pressure pump unit 2 enters the ammonia liquefaction device 90 through the spray pipe, thereby causing the ammonia entering the ammonia liquefaction device 90 to liquefy into a liquid state. The liquefied ammonia then re-enters the system through the bottom outlet of the ammonia liquefaction device 90 for recycling.

[0064] As shown in Figure 1, the ammonia liquefaction device 90 also includes an outlet pipe 91 located at its top. The outlet of the outlet pipe 91 is connected to the outside atmosphere, and an ammonia concentration detector 92 is installed on the outlet pipe 91. The outlet pipe 91 is the exhaust outlet pipe of the ammonia liquefaction device 90, and the ammonia concentration detector 92 is used to detect the ammonia concentration in the outlet pipe 91.

[0065] In an optional embodiment, as shown in Figure 2, the first outlet of the ammonia capture tank 9 is connected to the ammonia liquefaction device 90 via an ammonia interface. When the engine 10 switches from gas mode to fuel mode or other demand modes, nitrogen is used to purge the liquid ammonia between the fuel valve assembly unit 4 and the engine 10 to the gas-liquid buffer tank 8, and the liquid ammonia is then permeated into the ammonia capture tank 9. At this time, the ammonia contains a portion of nitrogen. In the ammonia liquefaction device 90, the ammonia is partially liquefied and reused, while the nitrogen is discharged to the atmosphere through the outlet pipe 91. When the nitrogen contains a high concentration of ammonia, the mixed gas is recycled back to the ammonia liquefaction device 90 for liquefaction, thereby preventing the excessive emission of ammonia into the atmosphere.

[0066] In an optional embodiment, as shown in Figure 2, the second outlet of the ammonia capture tank 9 is connected to the inlet of the ammonia buffer tank 61 via the ammonia compressor 71. The ammonia in the ammonia capture tank 9 is pressurized and used to replenish the ammonia in the denitrification unit 20. In gas combustion mode, the ammonia from the ammonia capture tank 9 is pressurized by the ammonia compressor 71 and supplied to the ammonia buffer tank 61 to replenish the ammonia in the denitrification unit 20.

[0067] In an optional embodiment, as shown in Figure 1, unreacted ammonia and unreacted carbon dioxide in the urea generating unit 50 pass sequentially through an ammonia-carbon dioxide buffer tank 60 and an ammonia-carbon dioxide separator 70. The ammonia-carbon dioxide buffer tank 60 is used to collect the unreacted ammonia and carbon dioxide in the urea generating unit 50, and the ammonia-carbon dioxide separator 70 is used to separate the ammonia and carbon dioxide. As shown in Figure 1, the carbon dioxide separated by the ammonia-carbon dioxide separator 70 enters the urea generating unit 50 after passing through a carbon dioxide compressor 420, which is used for carbon dioxide pressurization. As shown in Figure 2, the ammonia separated by the ammonia-carbon dioxide separator 70 enters the urea generating unit 50 through an ammonia compressor 71. In fuel mode, the pure ammonia separated by the ammonia-carbon dioxide separator 70 is pressurized by the ammonia compressor 71 and then supplied to the urea generating unit 50 again as a raw material for urea reaction, thus reusing it to improve utilization efficiency. Alternatively, as shown in Figure 2, the ammonia separated by the ammonia-carbon dioxide separator 70 enters the ammonia liquefaction unit 90 through an ammonia inlet. The ammonia in the ammonia capture tank 9 and the ammonia separated by the ammonia-carbon dioxide separation device 70 enter the ammonia liquefaction device 90 through the ammonia interface.

[0068] In an optional embodiment, as shown in Figure 4, the second outlet of the carbon dioxide separator 40 is connected to the inlet of the nitrogen separator 80, and the exhaust outlet of the nitrogen separator 80 is connected to the first outlet of the exhaust pipe 30. The nitrogen separator 80 is used to purify nitrogen in the exhaust gas. A carbon dioxide compressor 420 is provided between the first outlet of the carbon dioxide separator 40 and the urea generating device 50, and the carbon dioxide compressor 420 is used to pressurize the carbon dioxide.

[0069] When engine 10 is in fuel mode, the exhaust gas from the combustion of fossil fuel contains a significant amount of carbon dioxide. To meet carbon emission targets, some of the carbon dioxide in the exhaust gas can be post-treated based on the actual required emission reduction. The basic process for carbon emission post-treatment is as follows: a portion of the high-temperature exhaust gas requiring treatment is led to the carbon dioxide separator 40 via the exhaust fan 410. The separated carbon dioxide is sent to the carbon dioxide compressor 420 for pressurization, and the high-temperature, high-pressure carbon dioxide enters the urea generation unit 50. Simultaneously, liquid ammonia is converted into high-pressure ammonia gas via the low-pressure pump unit 2, the high-pressure pump unit 5, and the ammonia evaporator 6. This high-pressure ammonia gas enters the urea generation unit 50 through the first outlet of the ammonia evaporator 6. In the urea generation unit 50, ammonia and carbon dioxide undergo a complex reaction under high temperature, high pressure, and catalyst conditions, ultimately producing a urea solution.

[0070] The nitrogen outlet of the nitrogen separator 80 is connected to the nitrogen cylinder group 82 via the nitrogen compressor 81. The nitrogen cylinder group 82 is used to store high-pressure nitrogen. The nitrogen separated by the nitrogen separator 80 is pressurized by the nitrogen compressor 81 and stored in the nitrogen cylinder group 23. The nitrogen cylinder group 82 is connected to the outlet of the liquid supply valve group unit 41 and the inlet of the engine 10 via a nitrogen interface. It is used to purge the ammonia fuel supply line when the engine 10 switches from gas mode to fuel mode or other demand modes.

[0071] The marine ammonia treatment and exhaust gas decarbonization system provided in this embodiment can be used for ammonia treatment and exhaust gas decarbonization of ships transporting liquid ammonia or using ammonia power. It can be designed separately according to different operating conditions. When switching between fuel gas mode and fuel oil / fuel gas mode (purge), ammonia is liquefied and reused, or used as a reducing agent to supplement the denitrification device. In fuel oil mode, the exhaust gas is decarbonized by reacting ammonia and carbon dioxide to generate urea. The resulting urea solution can be dehydrated to form urea powder, which is convenient for onboard storage and saves layout space. The resulting urea solution can also be used as a reducing agent in the denitrification device. The system design also avoids the re-emission of carbon dioxide and can purify and utilize nitrogen in engine exhaust. By reusing ammonia and carbon dioxide in the exhaust of the urea generation device, the release of ammonia and carbon dioxide into the atmosphere is avoided, and the overall utilization efficiency of the system is improved.

[0072] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A marine ammonia treatment and exhaust gas decarbonization system, characterized in that, At least including: A low-pressure pump unit, the low-pressure pump unit including a first low-pressure pump and a second low-pressure pump, the first low-pressure pump and the second low-pressure pump being redundant to each other; A high-pressure supply unit, comprising a first high-pressure fuel pump, a second high-pressure fuel pump, and a heat exchanger, wherein the first high-pressure fuel pump and the second high-pressure fuel pump are redundant to each other, and the outlet of the first high-pressure fuel pump or the outlet of the second high-pressure pump is connected to the inlet of the heat exchanger. The fuel assembly unit includes a supply valve assembly unit and a return valve assembly unit. A high-pressure pump unit, comprising a first high-pressure pump and a second high-pressure pump, wherein the first high-pressure pump and the second high-pressure pump are redundant to each other; Ammonia evaporator; An engine, comprising a gas combustion mode and a fuel oil mode, wherein the gas combustion mode uses ammonia as fuel; and the fuel oil mode uses fossil fuel as fuel; the ammonia fuel outlet of the engine is connected to the inlet of the return valve assembly unit, and the first outlet of the return valve assembly unit is connected to a pipeline between the outlet of the low-pressure pump unit and the inlet of the high-pressure supply unit; a denitrification device, wherein the inlet of the denitrification device is connected to the exhaust outlet of the engine. An exhaust pipe, wherein the inlet of the exhaust pipe is connected to the outlet of the denitrification device, and the first outlet of the exhaust pipe is connected to the outside; A carbon dioxide separation device, wherein the inlet of the carbon dioxide separation device is connected to the second outlet of the exhaust pipe via an exhaust fan; The urea generating device has a first outlet connected to the carbon dioxide separation device; the outlet of the urea generating device is connected to a urea solution tank, and a level gauge is installed inside the urea generating device; a first control valve is installed between the urea generating device and the urea solution tank; the first outlet of the urea solution tank is connected to the denitrification device through a urea treatment device, for supplying the denitrification device with the reducing agent urea. The second outlet of the urea solution cabinet is connected to the urea powder generating device; The liquid ammonia storage tank has its outlet connected in sequence to the ammonia fuel inlet of the engine via the low-pressure pump unit, the high-pressure supply unit, and the liquid supply valve group unit; or, the outlet of the liquid ammonia storage tank is connected in sequence to the low-pressure pump unit, the high-pressure pump unit, and the ammonia evaporator, with the first outlet of the ammonia evaporator connected to the urea generating device to supply ammonia to the urea generating device; and the second outlet of the ammonia evaporator connected to the denitrification device to supply ammonia to the denitrification device.

2. The marine ammonia treatment and exhaust gas decarbonization system according to claim 1, characterized in that, An ammonia buffer tank is provided between the second outlet of the ammonia evaporator and the denitrification device, and a second control valve is provided between the ammonia buffer tank and the denitrification device.

3. The marine ammonia treatment and exhaust gas decarbonization system according to claim 2, characterized in that, It also includes a liquid ammonia buffer tank, the second outlet of the return valve assembly unit is connected to the inlet of the liquid ammonia buffer tank, and the outlet of the liquid ammonia buffer tank is connected to the pipeline between the outlet of the low-pressure pump unit and the inlet of the high-pressure supply unit.

4. The marine ammonia treatment and exhaust gas decarbonization system according to claim 3, characterized in that, It also includes an ammonia capture tank and a gas-liquid buffer tank. The inlet of the gas-liquid buffer tank is connected to the ammonia fuel outlet of the engine and the inlet of the return valve assembly unit via a pipeline. The gas-liquid buffer tank, the high-pressure supply unit and the liquid ammonia buffer tank are vented to the ammonia capture tank.

5. The marine ammonia treatment and exhaust gas decarbonization system according to claim 4, characterized in that, It also includes an ammonia liquefaction device, wherein the pipeline between the outlet of the low-pressure pump unit and the inlet of the high-pressure supply unit is connected to the ammonia liquefaction device via a spray pipe; the inlet of the ammonia liquefaction device is connected to an ammonia interface; and the bottom outlet of the ammonia liquefaction device is connected to the inlet of the low-pressure pump unit.

6. The marine ammonia treatment and exhaust gas decarbonization system according to claim 5, characterized in that, The ammonia liquefaction device includes an outlet pipe located at its top, the outlet of which is connected to the outside, and an ammonia concentration detector is installed on the outlet pipe.

7. The marine ammonia treatment and exhaust gas decarbonization system according to claim 6, characterized in that, The first outlet of the ammonia capture tank is connected to the ammonia liquefaction device through the ammonia interface; the second outlet of the ammonia capture tank is connected to the inlet of the ammonia buffer tank through the ammonia compressor.

8. The marine ammonia treatment and exhaust gas decarbonization system according to claim 5, characterized in that, In the urea generating device, unreacted ammonia and unreacted carbon dioxide pass sequentially through an ammonia-carbon dioxide buffer tank and an ammonia-carbon dioxide separator. The carbon dioxide separated by the ammonia-carbon dioxide separation device enters the urea generation device after passing through a carbon dioxide compressor. The ammonia separated by the ammonia-carbon dioxide separation device enters the urea generation device after passing through the ammonia compressor. Alternatively, the ammonia separated by the ammonia-carbon dioxide separation device enters the ammonia liquefaction device through the ammonia interface.

9. The marine ammonia treatment and exhaust gas decarbonization system according to claim 1, characterized in that, The second outlet of the carbon dioxide separator is connected to the inlet of the nitrogen separator, and the exhaust outlet of the nitrogen separator is connected to the first outlet of the exhaust pipe.

10. The marine ammonia treatment and exhaust gas decarbonization system according to claim 9, characterized in that, The nitrogen outlet of the nitrogen separation device is connected to a nitrogen cylinder group via a nitrogen compressor.

11. The marine ammonia treatment and exhaust gas decarbonization system according to claim 10, characterized in that, The ammonia cylinder group is connected to the outlet of the liquid supply valve group unit and the inlet of the engine via a nitrogen inlet.

12. The marine ammonia treatment and exhaust gas decarbonization system according to claim 1, characterized in that, A carbon dioxide compressor is installed between the first outlet of the carbon dioxide separation device and the urea generation device.

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