Exhaust aftertreatment a-SCR system and method for ammonia-fueled low-speed engine

Abstract

The present invention belongs to the technical field of marine engines, in particular to an exhaust aftertreatment A-SCR system and method for an ammonia-fueled low-speed engine. The system comprises an SCR controller, an SCR reactor, an ammonia supply system and an exhaust header, the exhaust header being separately connected to an exhaust end of a low-speed engine and the SCR reactor; the SCR controller is used for calculating, on the basis of a gas concentration signal in the exhaust header, the amount of ammonia gas that needs to be additionally injected, and controlling the ammonia supply system to supply ammonia gas to the exhaust header; and the additionally injected ammonia gas and exhaust gas of the low-speed engine are mixed in the exhaust header and then enter the SCR reactor. The present invention uses an existing ammonia fuel of a shipyard as a supplementary reducing agent, and provides a heating device to adjust the temperature of ammonia gas; and the heated ammonia gas is mixed with the exhaust gas of the low-speed engine in the exhaust header and then enters the SCR reactor, thereby avoiding the crystallization problem caused by low temperature.

Description

A-SCR system and method for exhaust aftertreatment of ammonia fuel low-speed engines

[0001] Cross-reference to related applications

[0002] This invention claims priority to Chinese Patent Application No. 202411591173.5, filed on November 8, 2024, entitled “A-SCR System and Method for Exhaust Aftertreatment of Ammonia Fuel Low-Speed ​​Engine”, the entire contents of which are incorporated herein by reference and constitute a part of this invention for all purposes. Technical Field

[0003] This invention belongs to the field of marine engine technology, and particularly relates to an exhaust aftertreatment A-SCR system and method for ammonia-fueled low-speed engine. Background Technology

[0004] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0005] The maritime industry is a pillar of global trade, with most global freight transported by sea. The proportion of global carbon dioxide emissions from maritime transport is increasing year by year. To curb greenhouse gas emissions from shipping, the International Maritime Organization (IMO) has continuously issued new mandatory conventions and targets to control ship greenhouse gas emissions and revised its greenhouse gas reduction targets. However, measures such as increasing ship size and improving propulsion systems have significant limitations in reducing ship greenhouse gas emissions. Ammonia (A) is the most promising carbon-free energy source, with a significant advantage in energy density and high fuel economy, making it a viable carbon-free power fuel for the maritime sector.

[0006] When ammonia fuel is burned in a marine engine, it produces only nitrogen dioxide (NO2). x The ammonia combustion process produces nitrous oxide (N2O) and unburned NH3. Toxic and harmful nitrogen oxide gases can be treated by selective catalytic reduction (SCR). However, unlike diesel fuel, the exhaust gas produced after ammonia combustion is at a lower temperature than that of a diesel engine, which places higher demands on the reduction reaction.

[0007] Furthermore, ammonia combustion produces N2O, which has a greenhouse effect nearly 300 times stronger than NO2, and current conventional SCR systems cannot effectively handle N2O. In addition, due to the incomplete combustion of ammonia, a large amount of NH3 escapes; and NH3 is toxic, so classification societies and other organizations have imposed restrictions on its emission concentration.

[0008] Generally, conventional SCR systems use a 40% urea solution as a reducing agent, which is sprayed into the mixing pipe through a urea spray gun. Under the action of high-temperature exhaust gas, the urea solution thermally generates NH3, which reacts with NO in the exhaust gas. x The reaction produces N2 and water.

[0009] However, in actual use, especially under low-load conditions, the exhaust gas temperature from the engine is low, resulting in a slow urea pyrolysis rate. Furthermore, when it encounters the cold inner wall of the mixing pipe, it easily deposits in the low-temperature region, forming crystals and affecting the final emission performance. In addition, urea solution, as a special chemical medium, requires a dedicated urea solution storage device, which occupies a very large space and affects the layout and installation of equipment on board. Summary of the Invention

[0010] To overcome the shortcomings of the prior art, the present invention provides an exhaust aftertreatment A-SCR system and method for ammonia-fueled low-speed engine.

[0011] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0012] The first aspect of the present invention provides an exhaust aftertreatment A-SCR system for an ammonia-fueled low-speed engine, including an SCR controller, an SCR reactor, an ammonia supply system, and an exhaust manifold, wherein the exhaust manifold is connected to the exhaust end of the low-speed engine and the SCR reactor respectively.

[0013] The exhaust manifold is equipped with a gas concentration sensor that is electrically connected to the SCR controller. The SCR controller is used to calculate the amount of additional ammonia gas that needs to be injected into the exhaust manifold based on the gas concentration signal, and to control the ammonia supply system to supply ammonia gas into the exhaust manifold.

[0014] The ammonia supply system includes an ammonia tank, a heating device, an ammonia supply pump, a proportional valve, and a spray gun, which are connected in sequence through a supply pipeline. The liquid ammonia supplied by the ammonia tank is changed from liquid to gaseous under the action of the heating device. The ammonia gas enters the spray gun after being regulated by the ammonia supply pump and the proportional valve in sequence. The spray gun is installed at the end of the exhaust manifold that is connected to the low-speed engine and is used to spray ammonia gas into the exhaust manifold.

[0015] The second aspect of this invention provides an exhaust aftertreatment method for a low-speed ammonia-fueled engine, based on the A-SCR exhaust aftertreatment system for a low-speed ammonia-fueled engine provided in the first aspect of this invention, comprising:

[0016] The operating mode of the low-speed engine is obtained. If the low-speed engine is operating in ammonia Tier II mode, the SCR controller controls the ammonia supply system to shut down; the exhaust gas from the low-speed engine enters the SCR reactor through the exhaust manifold to undergo reaction.

[0017] If the low-speed engine is operating in Tier III ammonia mode, the SCR controller calculates the amount of additional ammonia that needs to be injected into the exhaust manifold based on the gas concentration signal in the exhaust manifold, and controls the ammonia supply system to supply ammonia into the exhaust manifold; the exhaust gas from the low-speed engine and the ammonia supplied by the ammonia supply system mix in the exhaust manifold and then enter the SCR reactor to react.

[0018] The above one or more technical solutions have the following beneficial effects:

[0019] (1) The ammonia supply system provided by the present invention uses the existing ammonia fuel in the shipyard as a supplementary reducing agent for the SCR system, eliminating the pyrolysis process of urea solution and avoiding the problem of difficult pyrolysis and easy crystallization of urea solution under low load conditions; at the same time, by setting a heating device to adjust the temperature of ammonia gas, the heated ammonia gas is mixed with the exhaust gas of the low-speed engine in the exhaust manifold and then enters the SCR reactor, ensuring the smooth progress of the reaction and avoiding the crystallization problem caused by low temperature.

[0020] (2) This invention utilizes NH3, which is unburned from ammonia fuel, as a reducing agent on the one hand, and NH3 provided by the ammonia supply system as a supplementary reducing agent on the other hand. Through the control logic of the SCR control system, the amount of ammonia that needs to be injected is calculated, and the ammonia supply system is controlled to inject ammonia into the exhaust manifold, so that the ammonia and the exhaust gas are mixed in the exhaust pipe. This method reduces the design of the urea tank and the setting of the mixer, saves shipyard space, and reduces the pyrolysis process of the urea solution, effectively solving the crystallization problem of the urea solution under low temperature conditions.

[0021] (3) The SCR reactor provided by this invention is equipped with three different types of catalysts, which can simultaneously treat NO in waste gas under various conditions. x The emissions of nitrogen, nitrogen, oxygen, and escaped NH3 must meet the requirements of relevant regulations.

[0022] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0024] Figure 1 is a system structure diagram of the first embodiment.

[0025] Figure 2 is a flowchart of the PID regulation of ammonia supply in the first embodiment.

[0026] In the diagram, 1. Ammonia tank; 2. Ammonia supply system; 3. Control valve assembly; 4. Heating device; 5. Filter; 6. Ammonia supply pump; 7. Flow meter; 8. Proportional valve; 9. Spray gun; 10. Exhaust manifold; 11. N2O sensor; 12. NO. x 13. Sensor, NH3 sensor, 14. SCR controller, 15. Low-speed engine, 16. RSV valve, 17. SCR reactor, 18. Denitrification catalyst, 19. Conventional catalyst, 20. Deammoniation catalyst, 21. RTV valve, 22. RBV valve, 23. Turbocharger, 24. Overflow valve, 25. Cooling and pressurizing device. Detailed Implementation

[0027] Example 1

[0028] As shown in Figure 1, this embodiment discloses an exhaust aftertreatment A-SCR system for an ammonia-fueled low-speed engine, including an SCR controller 14, an SCR reactor 17, an ammonia supply system, and an exhaust manifold 10; the exhaust manifold 10 is connected to the exhaust end of the low-speed engine and the SCR reactor 17 respectively.

[0029] The exhaust gas from the low-speed engine 15 first enters the exhaust manifold 10. When the ammonia supply system is started, the ammonia supply system supplies ammonia to the exhaust manifold 10. The exhaust gas from the low-speed engine 15 and the ammonia supplied by the ammonia supply system are mixed in the exhaust manifold 10. The mixed gas enters the SCR reactor 17, reacts, and is then discharged.

[0030] The exhaust gas from the low-speed engine 15 contains not only a large amount of NO produced by the combustion of NH3, but also... x In addition, it contains a large amount of incompletely burned NH3 and a small amount of N2O. Therefore, this incompletely burned NH3 can be used as a reducing agent to carry out subsequent selective catalytic reduction reactions, thereby reducing the supply and consumption of ammonia.

[0031] The ammonia supply system includes an ammonia tank 1, an ammonia gas supply system 2, a control valve group 3, a heating device 4, an ammonia supply pump 6, a proportional valve 8, and a spray gun 9, which are connected in sequence through a supply pipeline. The supply of ammonia is controlled by the control valve group 3. When the control valve group 3 is opened, the liquid ammonia supplied by the ammonia tank 1 changes from liquid to gas under the action of the heating device 4. After the ammonia gas passes through the ammonia supply pump 6, the supply flow rate of ammonia gas is adjusted in real time by controlling the opening of the proportional valve 8. The spray gun 9 is installed at the end of the exhaust manifold 10 that is connected to the low-speed engine. The spray gun 9 is used to spray ammonia gas into the exhaust manifold 10.

[0032] In this embodiment, the ammonia tank 1 is used to provide ammonia reducing agent. The ammonia tank is equipped with a control valve group 3, which is used to control the supply of ammonia reducing agent. If the low-speed engine 15 is in a stopped state or does not need to supply NH3 to the exhaust manifold 10, the control valve group 3 is cut off to ensure the safety of the system.

[0033] When the SCR system is started, the control valve group 3 opens, and liquid ammonia enters the heating device 4 through the supply pipeline. The heating device 4 is used to heat the liquid ammonia to a suitable temperature, so that the ammonia changes from liquid to gas.

[0034] The spray gun 9 is installed at the end of the exhaust manifold 10 and is used to spray gaseous ammonia into the exhaust manifold 10. With the help of the complex exhaust gas flow field in the exhaust manifold, the ammonia and exhaust gas are fully mixed so that the next reaction can proceed.

[0035] This invention does not use the conventional 40% urea solution as a reducing agent. Instead, it uses ammonia fuel from an ammonia-fueled engine and NH3 escaping from the exhaust gas as a reducing agent. This eliminates the pyrolysis process of the urea solution and avoids the problems of difficult pyrolysis and easy crystallization of the urea solution under low load conditions. At the same time, the choice of ammonia reducing agent reduces the design of the urea tank, greatly saving space and reducing workload.

[0036] As a further embodiment, the ammonia supply pump 6 is a fixed-frequency pump, and a filter 5 is provided on the supply pipeline between the heating device 4 and the ammonia supply pump 6. The filter 5 is used to filter impurities in the ammonia gas to avoid pipeline blockage.

[0037] As a further embodiment, a flow meter 7 is provided on the supply pipeline between the ammonia supply pump 6 and the proportional valve 8. The flow meter 7 is electrically connected to the SCR controller. The flow meter 7 is used to detect the amount of ammonia supplied in the supply pipeline in real time and transmit it to the SCR controller.

[0038] As a further embodiment, the ammonia supply system also includes an overflow valve 24 and a cooling and pressurizing device 25 connected in sequence through a recovery pipeline; the overflow valve 24 is connected to the supply pipeline between the ammonia supply pump 6 and the flow meter 7 through the recovery pipeline, and the cooling and pressurizing device 25 is connected to the ammonia tank 1 through the recovery pipeline.

[0039] The ammonia gas flowing through the ammonia supply pump 6 passes through the flow meter 7, the proportional valve 8, and the spray gun 9 and is injected into the exhaust manifold 10. The excess ammonia gas enters the cooling and pressurizing device 25 through the overflow valve 24. The cooling and pressurizing device 25 is used to convert the excess ammonia gas into liquid ammonia and then return it to the ammonia tank 1.

[0040] The ammonia supply pump 6 is used to supply a fixed amount of ammonia to the SCR system. The SCR controller 14 adjusts the opening of the proportional valve 8 in real time according to the required ammonia supply, thereby achieving precise control of the ammonia supply. Excess ammonia flows back into the ammonia tank 1 through the overflow valve 24 and the cooling and pressurizing device 25.

[0041] As a further embodiment, a gas concentration sensor is provided inside the exhaust manifold 10, including an NH3 sensor 11 and a NO sensor 12. x Sensor 12 and N2O sensor 13, gas concentration sensor are electrically connected to SCR controller 14 and are used to feed back the collected signal to SCR controller 14.

[0042] The SCR controller 14 calculates the amount of ammonia that the ammonia supply system needs to inject into the exhaust manifold 10 by using the feedback concentration signal, and adjusts the actual ammonia supply by adjusting the opening of the proportional valve 6 to inject the specified amount of ammonia. As shown in Figure 2, the PID control method is used to monitor and compare the deviation between the feedback value and the set value of the ammonia supply to achieve precise control of the ammonia supply.

[0043] As a further embodiment, the SCR reactor 17 is a multifunctional reactor with an inlet end at the top and an outlet end at the bottom. The SCR reactor contains a denitrification catalyst 18, a conventional catalyst 19, and a deammoniation catalyst 20 arranged sequentially from the inlet end to the outlet end.

[0044] This invention addresses the removal of N2O from waste gas by adding a denitrification catalyst to the SCR reactor 17, thereby converting N2O in the waste gas into NO. x To reduce N2O emissions and generate NO x It can also be removed by subsequent conventional catalysts.

[0045] The number of layers of denitrification catalyst 18, conventional catalyst 19, and deammoniation catalyst 20 can be selected as needed. In this embodiment, one layer of denitrification catalyst, three layers of conventional catalyst, and one layer of deammoniation catalyst are used. This invention, by setting three different catalysts in the SCR reactor 17, can simultaneously treat multiple components in the waste gas, such as NO. x The system incorporates N2O and escaped ammonia to ensure that exhaust emissions meet relevant regulations, making the system more comprehensive.

[0046] As a further embodiment, an RSV valve 16 is provided on the pipeline between the exhaust manifold 10 and the inlet end of the SCR reactor, and an RTV valve 21, a turbocharger 23 and an RBV valve 22 are sequentially provided on the pipeline between the exhaust manifold 10 and the outlet end of the SCR reactor.

[0047] When the low-speed engine 15 is operating in ammonia Tier II mode, the NO in the low-speed engine exhaust...x The emissions meet the requirements; it is sufficient to treat the NH3 and N2O in the exhaust to meet regulatory requirements.

[0048] The exhaust gas from the low-speed engine enters the exhaust manifold 10. Since the exhaust gas contains a large amount of unburned NH3, in order to ensure that the NH3 emission meets the requirements, the ammonia supply system and RBV valve 22 are closed, and RSV valve 16 and RTV valve 21 are opened, so that the exhaust gas enters the SCR reactor through the SCR pipeline to react. The A-SCR system starts the passive operation mode.

[0049] The exhaust gas from the low-speed engine flows out of the exhaust manifold 10, passes through the SCR pipeline and RSV valve 16, and enters the SCR reactor 17. Inside the SCR reactor 17, the exhaust gas first passes through the denitrification catalyst 18, where N2O in the exhaust gas is converted into NO under the action of the denitrification catalyst 18. x And other NO in the exhaust x After thorough mixing, the mixture flows through conventional catalyst 19, at which point the NO in the exhaust gas... x NH3 undergoes a reduction reaction with conventional catalyst 19 to produce N2 and water; however, the concentration of escaping NH3 is greater than that of NO. x The excess NH3 is then removed by the deammoniation catalyst 20 in the SCR reactor 17, thereby reducing NO. x Both NH3 emissions meet the requirements; finally, the exhaust gas is discharged through RTV valve 21 and turbocharger 23.

[0050] When the low-speed engine is running in ammonia Tier III mode, the SCR controller 14 calculates the amount of additional ammonia that needs to be injected into the exhaust manifold based on the gas concentration signal, and controls the ammonia supply system to supply ammonia into the exhaust manifold 10.

[0051] The ammonia injected additionally by the ammonia supply system interacts with the NH3 and NO in the exhaust of the low-speed engine. x The mixture is thoroughly mixed in the exhaust manifold 10, and the mixed gas enters the SCR reactor 17 to react.

[0052] Specifically: the mixed exhaust gas first reaches the first layer of catalyst 18 in the SCR reactor 17, where the N2O in the exhaust gas is oxidized to NO under the catalytic action of the denitrification catalyst 18. x And together with the original NO in the exhaust gas x After being mixed with NH3, a reduction reaction occurs under the action of conventional catalyst 19, which is placed after the denitrification catalyst 18, thereby removing NO from the waste gas. x .

[0053] If excessive NH3 is produced after ammonia combustion, and the SCR controller 14 calculates that no additional ammonia injection is needed, then the control valve 8 is set to 0, and no ammonia is injected into the exhaust manifold 10. The exhaust gas then enters the SCR reactor 17 via the RSV valve 16, where, under the action of the denitrification catalyst 18, the N2O in the exhaust gas is oxidized to NO. x NO in exhaust gas x Under the action of conventional catalyst 19, NH3 undergoes a reduction reaction, and excess NH3 can be removed by deammoniation catalyst 20 set after conventional catalyst 19 to meet emission requirements.

[0054] When a low-speed engine is operating in diesel Tier II mode, the NO in the exhaust gas of the low-speed engine... x To meet emission requirements, the SCR controller shuts down the ammonia supply system, and the A-SCR system does not operate. At this time, the RSV valve 16 and RTV valve 21 are closed, and the RBV valve 22 is opened. The exhaust gas enters the turbocharger 23 directly through the RBV valve 22 and is then discharged.

[0055] If the low-speed engine is operating in diesel Tier III mode, the SCR controller calculates the amount of additional ammonia needed to be injected into the exhaust manifold based on the gas concentration signal in the exhaust manifold, and controls the ammonia supply system to supply ammonia to the exhaust manifold 10. The exhaust gas from the low-speed engine mixes with the ammonia supplied by the ammonia supply system in the exhaust manifold before entering the SCR reactor 17 to react. In this mode, the exhaust gas does not contain N2O or NH3; therefore, after reaching the SCR reactor 17, NO is only reduced under the action of the conventional catalyst 19. x It undergoes a reduction reaction with NH3, thereby removing NO from the waste gas. x .

[0056] Example 2

[0057] This embodiment discloses an exhaust aftertreatment method for an ammonia-fueled low-speed engine, based on the A-SCR exhaust aftertreatment system for an ammonia-fueled low-speed engine disclosed in Embodiment 1, comprising:

[0058] The operating mode of the low-speed engine is obtained. If the low-speed engine is operating in ammonia Tier II mode, the SCR controller controls the ammonia supply system to shut down; the exhaust gas from the low-speed engine enters the SCR reactor through the exhaust manifold to undergo reaction.

[0059] If the low-speed engine is operating in Tier III ammonia mode, the SCR controller calculates the amount of additional ammonia that needs to be injected into the exhaust manifold based on the gas concentration signal in the exhaust manifold, and controls the ammonia supply system to supply ammonia into the exhaust manifold; the exhaust gas from the low-speed engine and the ammonia supplied by the ammonia supply system mix in the exhaust manifold and then enter the SCR reactor to react.

[0060] If the low-speed engine is running in diesel Tier II mode, the SCR controller controls the ammonia supply system to shut down, and controls the RSV valve and RTV valve to close, while the RBV valve opens, allowing exhaust gas to enter the turbocharger and then be discharged.

[0061] If the low-speed engine is running in diesel Tier III mode, the SCR controller calculates the amount of additional ammonia that needs to be injected into the exhaust manifold based on the gas concentration signal in the exhaust manifold, and controls the ammonia supply system to supply ammonia into the exhaust manifold. The exhaust gas from the low-speed engine mixes with the ammonia supplied by the ammonia supply system in the exhaust manifold and then enters the SCR reactor to react. The reacted gas passes through the RTV valve and the turbocharger in sequence before being discharged.

[0062] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0063] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. An exhaust aftertreatment A-SCR system for a low-speed ammonia-fueled engine, characterized in that, It includes an SCR controller, an SCR reactor, an ammonia supply system, and an exhaust manifold, wherein the exhaust manifold is connected to the exhaust end of the low-speed engine and the SCR reactor, respectively. The exhaust manifold is equipped with a gas concentration sensor that is electrically connected to the SCR controller. The SCR controller is used to calculate the amount of additional ammonia gas that needs to be injected into the exhaust manifold based on the gas concentration signal, and to control the ammonia supply system to supply ammonia gas into the exhaust manifold. The ammonia supply system includes an ammonia tank, a heating device, an ammonia supply pump, a proportional valve, and a spray gun, which are connected in sequence through a supply pipeline. The liquid ammonia supplied by the ammonia tank is changed from liquid to gaseous under the action of the heating device. The ammonia gas enters the spray gun after being regulated by the ammonia supply pump and the proportional valve in sequence. The spray gun is installed at the end of the exhaust manifold that is connected to the low-speed engine and is used to spray ammonia gas into the exhaust manifold.

2. The exhaust aftertreatment A-SCR system for a low-speed ammonia-fueled engine as described in claim 1, characterized in that, The ammonia tank is equipped with a control valve assembly, which controls the opening and closing of the ammonia tank.

3. The exhaust aftertreatment A-SCR system for a low-speed ammonia-fueled engine as described in claim 1, characterized in that, A filter is installed on the supply pipeline between the heating device and the ammonia supply pump, and the filter is used to filter impurities in the ammonia gas.

4. The exhaust aftertreatment A-SCR system for a low-speed ammonia-fueled engine as described in claim 1, characterized in that, A flow meter is installed on the supply pipeline between the ammonia supply pump and the proportional valve. The flow meter is electrically connected to the SCR controller. The flow meter is used to detect the amount of ammonia supplied in the supply pipeline and transmit it to the SCR controller.

5. The exhaust aftertreatment A-SCR system for a low-speed ammonia-fueled engine as described in claim 4, characterized in that, The ammonia supply system also includes an overflow valve and a cooling and pressurizing device connected in sequence through a recovery pipeline. The overflow valve is connected to the supply pipeline between the ammonia supply pump and the flow meter through the recovery pipeline, and the cooling and pressurizing device is connected to the ammonia tank through the recovery pipeline. The ammonia gas flowing through the ammonia supply pump enters the cooling and pressurizing device through the overflow valve. The cooling and pressurizing device is used to convert excess ammonia gas into liquid ammonia and then return it to the ammonia tank.

6. The exhaust aftertreatment A-SCR system for a low-speed ammonia-fueled engine as described in claim 1, characterized in that, An RSV valve is installed on the pipeline between the exhaust manifold and the inlet end of the SCR reactor, and an RTV valve, a turbocharger, and an RBV valve are sequentially installed on the pipeline between the exhaust manifold and the outlet end of the SCR reactor.

7. The exhaust aftertreatment A-SCR system for a low-speed ammonia-fueled engine as described in claim 1, characterized in that, The gas concentration signal includes N2O concentration, NO concentration, etc. x Concentration and NH3 concentration.

8. The exhaust aftertreatment A-SCR system for a low-speed ammonia-fueled engine as described in claim 1, characterized in that, The SCR reactor contains a denitrification catalyst, a conventional catalyst, and a deammoniation catalyst in sequence from the inlet to the outlet.

9. An exhaust aftertreatment method for an ammonia-fueled low-speed engine, based on the A-SCR exhaust aftertreatment system for an ammonia-fueled low-speed engine according to any one of claims 1-8, characterized in that, include: The operating mode of the low-speed engine is obtained. If the low-speed engine is operating in ammonia Tier II mode, the SCR controller controls the ammonia supply system to shut down; the exhaust gas from the low-speed engine enters the SCR reactor through the exhaust manifold to undergo reaction. If the low-speed engine is operating in Tier III ammonia mode, the SCR controller calculates the amount of additional ammonia that needs to be injected into the exhaust manifold based on the gas concentration signal in the exhaust manifold, and controls the ammonia supply system to supply ammonia into the exhaust manifold; the exhaust gas from the low-speed engine and the ammonia supplied by the ammonia supply system mix in the exhaust manifold and then enter the SCR reactor to react.

10. The method as described in claim 9, characterized in that, include: If the low-speed engine is running in diesel Tier II mode, the SCR controller controls the ammonia supply system to shut down, and controls the RSV valve and RTV valve to close, while the RBV valve opens, so that exhaust gas enters the turbocharger and is then discharged. If the low-speed engine is operating in diesel Tier III mode, the SCR controller calculates the amount of additional ammonia that needs to be injected into the exhaust manifold based on the gas concentration signal in the exhaust manifold, and controls the ammonia supply system to supply ammonia into the exhaust manifold; the exhaust gas from the low-speed engine and the ammonia supplied by the ammonia supply system mix in the exhaust manifold and then enter the SCR reactor to react; the reacted gas passes through the RTV valve and the turbocharger in sequence before being discharged.

Images