Ammonia fuelled marine engine system and exhaust aftertreatment system thereof
By designing an exhaust aftertreatment system for ammonia-fueled marine engines and optimizing the treatment process through catalytic reactions and bypass pathways, the problem of N2O and NH3 escape in the exhaust gas of ammonia-fueled marine engines was solved, achieving efficient pollutant conversion and recycling, and meeting emission standards.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CSSC POWER (GRP) CO LTD
- Filing Date
- 2022-11-24
- Publication Date
- 2026-05-19
AI Technical Summary
Existing technologies cannot effectively handle N2O in the exhaust gas of ammonia-fueled marine engines, and afterburning of ammonia fuel is difficult to avoid, resulting in a high risk of NH3 escape and failure to meet strict emission limits.
An exhaust gas aftertreatment system for ammonia-fueled marine engines was designed, comprising a nitrous oxide reactor, a denitrification oxide reactor, and an ammonia oxidation catalyst reactor. Through catalytic reduction and oxidation processes, N2O, NOx, and NH3 are converted into harmless substances. By employing bypass pathways and control logic to optimize the treatment process, escaped ammonia is recovered for use in the fuel supply system.
It effectively reduces NOx, NH3 and N2O emissions, lowers environmental impact, improves fuel efficiency, reduces system cost and operational complexity, and adapts to the installation requirements of different engine models.
Smart Images
Figure CN115773169B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of marine engine exhaust gas treatment technology, specifically to an ammonia-fueled marine engine system and its exhaust gas after-treatment system. Background Technology
[0002] Ammonia, as a carrier of carbon-free energy and a sustainable energy source, is internationally recognized as one of the most promising zero-carbon fuels with broad application prospects. Plans for the application and financing of future clean fuels have been initiated in this field. X Strict emission limits are already in place, and N2O emissions have been explicitly stated to need to be controlled. With the promotion of ammonia fuel in the shipping industry, emission limits for NH3 will also be gradually implemented.
[0003] N2O is a gas with a greenhouse effect 298 times greater than CO2. Currently, the mainstream marine denitrification system, SCR, cannot effectively treat N2O in the exhaust gas of ammonia-fueled ship engines. Furthermore, in the current SCR reaction process, NO... X The undesirable byproducts of NH3 also include N2O; due to the laminar combustion rate and low calorific value of NH3, afterburning of ammonia fuel is difficult to avoid, thus posing a high risk of ammonia escape. Therefore, to overcome these challenges, there is an urgent need in this field to fully integrate the already mature SCR technology and develop an aftertreatment system suitable for ammonia-fueled ships.
[0004] Currently, no descriptions or reports of technologies similar to this invention have been found, and no similar information has been collected domestically or internationally. Summary of the Invention
[0005] To address the aforementioned shortcomings in the prior art, this invention provides an ammonia-fueled marine engine system and its exhaust gas aftertreatment system.
[0006] According to one aspect of the present invention, an exhaust gas aftertreatment system for an ammonia-fueled marine engine system is provided, comprising: a nitrous oxide reactor, a denitrification oxide reactor, an ammonia oxidation catalyst reactor, and an emission system; wherein:
[0007] The inlet of the nitrous oxide reactor is connected to the ammonia fuel engine and the ammonia fuel supply system, respectively. The outlet of the nitrous oxide reactor is connected to the inlet of the denitrification oxide reactor. The outlet of the denitrification oxide reactor is connected to the inlet of the ammonia oxidation catalyst reactor. The outlet of the ammonia oxidation catalyst reactor is connected to the emission system.
[0008] A first connecting bypass is connected between the inlet and outlet ends of the nitrous oxide reactor.
[0009] A second connecting bypass is connected between the inlet and outlet ends of the ammonia oxidation catalyst reactor;
[0010] According to the processing control logic, the ammonia fuel engine and / or the ammonia fuel supply system are connected to the nitrous oxide reactor or connected to the denitrification oxide reactor through the first connection bypass; the denitrification oxide reactor is connected to the emission system through the ammonia oxidation catalyst reactor or connected to the emission system through the second connection bypass.
[0011] Optionally, the nitrous oxide reactor includes one or more layers of noble metal catalysts, which are arranged sequentially between each other to convert N2O into N2, O2, NO2 and NO by catalytic reduction using NH3 as a reducing agent.
[0012] Optionally, the denitrification reactor includes one or more vanadium catalyst layers arranged sequentially and a copper catalyst layer disposed at the rear end of the vanadium catalyst layer; wherein, the vanadium catalyst layer is used to catalytically reduce NO using NH3 as a reducing agent. X The copper catalyst layer is used to convert NH3 into N2 and H2O.
[0013] Optionally, the ammonia oxidation catalyst reactor includes one or more oxidation catalyst layers, which are arranged sequentially between each other to oxidize NH3 into N2 and H2O.
[0014] Optionally, the emission system includes an NH3 concentration sensor and an ammonia fuel recovery system; wherein:
[0015] The output of the NH3 concentration sensor is divided into two paths, one of which is connected to the ammonia fuel recovery system and the other is connected to the atmosphere.
[0016] The ammonia fuel recovery system is connected to the ammonia fuel supply system;
[0017] According to the emission control logic, the denitrification oxide reactor or the ammonia oxidation catalyst reactor is directly connected to the atmosphere or to the ammonia fuel recovery system through the NH3 concentration sensor.
[0018] Optionally, valves for preventing gas backflow are provided on the pipeline between the nitrous oxide reactor and the denitrification oxide reactor and / or on the pipeline between the denitrification oxide reactor and the ammonia oxidation catalyst reactor;
[0019] Control valves are respectively provided at the inlet ends of the nitrous oxide reactor and the ammonia oxidation catalyst reactor, as well as on the first connecting bypass and the second connecting bypass.
[0020] Optionally, the post-treatment system further includes an auxiliary heating system, which is connected to the nitrous oxide reactor and the denitrification oxide reactor, respectively.
[0021] Optionally, the processing control logic includes:
[0022] When the combustion mode of the ammonia fuel engine is mainly diesel-driven, the first connecting bypass is opened, and the ammonia fuel engine and the ammonia fuel supply system are connected to the denitrification oxide reactor through the first connecting bypass.
[0023] When the combustion mode of the ammonia fuel engine is ignited by diesel fuel to produce NH3 or the engine is primarily driven by NH3, the escaped ammonia in the exhaust gas components is measured to determine whether it is sufficient as a reducing agent to reduce N2O and NO. X If sufficient, the supply channel for ammonia reducing agent provided by the ammonia fuel supply system is closed; if insufficient, the supply channel for ammonia reducing agent provided by the ammonia fuel supply system is opened; simultaneously, the first connecting bypass is closed, and the ammonia fuel engine and / or the ammonia fuel supply system are connected to the nitrous oxide reactor.
[0024] When the escaped ammonia concentration output from the denitrification oxide reactor is less than or equal to a set threshold a, the escaped ammonia concentration in the exhaust gas component is measured to be less than NO. X If the concentration is positive, the second connection bypass is opened, and the denitrification oxide reactor is connected to the emission system through the second connection bypass; if not, the second connection bypass is closed, and the denitrification oxide reactor is connected to the emission system through the ammonia oxidation catalyst reactor.
[0025] Optionally, the emission control logic includes:
[0026] Determine whether the NH3 concentration detected by the NH3 sensor is less than or equal to a set threshold b; if so, connect directly to the atmosphere; if not, connect to the ammonia fuel recovery system to reuse the recovered NH3.
[0027] According to another aspect of the present invention, an ammonia-fueled marine engine system is provided, comprising: a fuel supply system, an ammonia-fueled engine, and an exhaust gas aftertreatment system as described in any one of the preceding claims, wherein the exhaust gas aftertreatment system is disposed at the rear end of the turbocharger of the ammonia-fueled engine and connected to the fuel supply system.
[0028] By adopting the above technical solution, the present invention has at least one of the following beneficial effects compared with the prior art:
[0029] The ammonia-fueled marine engine system and its exhaust aftertreatment system provided by this invention can treat three main pollutants in a synergistic manner. By utilizing the interaction characteristics of the three pollutants, the system reduces the introduction of other substances to participate in the catalytic reduction reaction, so that the pollutants can be mutually utilized in the overall treatment process, and the pollutant emissions can be treated at the same time.
[0030] The ammonia-fueled marine engine system and its exhaust aftertreatment system provided by this invention can recover escaped ammonia and return it to the fuel supply system, thereby controlling emissions.
[0031] The ammonia-fueled marine engine system and its exhaust aftertreatment system provided by this invention greatly reduce NO. X The emissions of NH3 and N2O are reduced, thereby further reducing the environmental impact of ammonia fuel use.
[0032] The ammonia-fueled marine engine system and its exhaust gas aftertreatment system provided by this invention minimize the introduction of other substances as reducing agents or reactants by arranging them in a specific order, thereby reducing the cost of system layout, maintenance and operation.
[0033] The ammonia-fueled marine engine system and its exhaust aftertreatment system provided by this invention place the equipment group in the aftertreatment system at the rear end of the turbocharger (T / C) of the ammonia-fueled engine. This arrangement can flexibly adapt to the arrangement and installation requirements of the aftertreatment system in the ship's cabin for more types of ammonia-fueled engines. Attached Figure Description
[0034] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:
[0035] Figure 1 This is a schematic diagram of the exhaust gas aftertreatment system in a preferred embodiment of the present invention.
[0036] Figure 2 This is a schematic diagram of the control logic of the exhaust gas aftertreatment system in a preferred embodiment of the present invention.
[0037] In the diagram, 1 to 10 represent the valves that control the corresponding pipelines. Detailed Implementation
[0038] The embodiments of the present invention are described in detail below: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.
[0039] One embodiment of the present invention provides an exhaust gas aftertreatment system for an ammonia-fueled marine engine system. This system combines the different combustion modes and exhaust gas composition characteristics of ammonia-fueled marine engines, and uses three exhaust pollutant treatment units as the main framework supplemented by a bypass treatment path, thus solving the problem of fuel ammonia escape in the prior art.
[0040] like Figure 1 As shown, the exhaust gas aftertreatment system for an ammonia-fueled marine engine system provided in this embodiment may include: a nitrous oxide reactor, a selective catalytic reduction (SCR) reactor, and an ammonia oxidation catalyst reactor (AOC); wherein:
[0041] in:
[0042] The inlet of the nitrous oxide reactor is connected to the ammonia fuel engine and the ammonia fuel supply system, respectively. The outlet of the nitrous oxide reactor is connected to the inlet of the denitrification oxide reactor. The outlet of the denitrification oxide reactor is connected to the inlet of the ammonia oxidation catalyst reactor. The outlet of the ammonia oxidation catalyst reactor is connected to the emission system.
[0043] A first connecting bypass is connected between the inlet and outlet ends of the nitrous oxide reactor;
[0044] A second connecting bypass is connected between the inlet and outlet ends of the ammonia oxidation catalyst reactor;
[0045] According to the processing control logic, the ammonia fuel engine and / or ammonia fuel supply system are connected to the nitrous oxide reactor or connected to the denitrification oxide reactor via a first connection bypass; the denitrification oxide reactor is connected to the emission system via the ammonia oxidation catalyst reactor or connected to the emission system via a second connection bypass.
[0046] In a preferred embodiment, the nitrous oxide reactor may include one or more layers of noble metal catalysts, which are arranged sequentially to convert N2O into N2, O2, NO2 and NO by catalytic reduction using NH3 as a reducing agent.
[0047] In a preferred embodiment, the denitrification oxide reactor may include one or more vanadium catalyst layers arranged sequentially and a copper catalyst layer disposed at the rear end of the vanadium catalyst layer; wherein, the vanadium catalyst layer is used to catalytically reduce NO using NH3 as a reducing agent. X It is converted into N2 and H2O; the copper catalyst layer is used to convert NH3 into N2 and H2O.
[0048] In a preferred embodiment, the ammonia oxidation catalyst reactor may include one or more oxidation catalyst layers, which are arranged sequentially to oxidize NH3 into N2 and H2O.
[0049] In a preferred embodiment, the emission system may include an NH3 concentration sensor and an ammonia fuel recovery system; wherein:
[0050] The output of the NH3 concentration sensor is divided into two paths, one of which is connected to the ammonia fuel recovery system and the other is connected to the atmosphere.
[0051] The ammonia fuel recovery system is connected to the ammonia fuel supply system;
[0052] According to the emission control logic, the denitrification oxide reactor or ammonia oxidation catalyst reactor is directly connected to the atmosphere or connected to the ammonia fuel recovery system through an NH3 concentration sensor.
[0053] In a preferred embodiment, valves for preventing gas backflow may be provided on the pipeline between the nitrous oxide reactor and the denitrification oxide reactor and / or on the pipeline between the denitrification oxide reactor and the ammonia oxidation catalyst reactor.
[0054] In a preferred embodiment, control valves may be provided at the inlet ends of the nitrous oxide reactor and the ammonia oxidation catalyst reactor, as well as on the first and second connecting bypasses.
[0055] In a preferred embodiment, the post-treatment system may further include an auxiliary heating system, which is connected to both the nitrous oxide reactor and the denitrification oxide reactor.
[0056] like Figure 2 As shown, the exhaust gas aftertreatment system provided in the above embodiments of the present invention has the following processing control logic and emission control logic.
[0057] In a preferred embodiment, the processing control logic may include:
[0058] When the combustion mode of the ammonia fuel engine is mainly diesel-driven, the first connecting bypass is opened, and the ammonia fuel engine and the ammonia fuel supply system are connected to the denitrification oxide reactor through the first connecting bypass.
[0059] When the combustion mode of an ammonia-fueled engine is either diesel-ignited NH3 or primarily driven by NH3, the escaped ammonia in the exhaust gas components is measured to determine whether it is sufficient as a reducing agent to reduce N2O and NO. XIf sufficient, the supply channel for ammonia reducing agent provided by the ammonia fuel supply system is closed; if insufficient, the supply channel for ammonia reducing agent provided by the ammonia fuel supply system is opened; simultaneously, the first connecting bypass is closed, and the ammonia fuel engine and / or ammonia fuel supply system are connected to the nitrous oxide reactor.
[0060] When the escaped ammonia concentration output from the denitrification oxide reactor is less than or equal to a set threshold 'a', measure whether the escaped ammonia concentration in the exhaust gas component is less than NO. X The concentration is controlled; if so, the second bypass is opened, and the nitrogen oxide removal reactor is connected to the emission system through the second bypass; if not, the second bypass is closed, and the nitrogen oxide removal reactor is connected to the emission system through the ammonia oxidation catalyst reactor. In a specific application example, the threshold a is set to 10 ppm.
[0061] In a preferred embodiment, the emission control logic may include:
[0062] The system determines whether the NH3 concentration detected by the NH3 sensor is less than or equal to a set threshold b. If so, it connects directly to the atmosphere; otherwise, it connects to the ammonia fuel recovery system for reuse of the recovered NH3. In a specific application example, the set threshold b is 6 g / kWh.
[0063] The technical solutions provided by the above embodiments of the present invention will be further described below.
[0064] The exhaust gas aftertreatment system provided in the above embodiments of the present invention employs a nitrous oxide reactor for purifying N2O. This reactor uses a precious metal catalyst, with the number of catalyst layers set according to actual emissions. It utilizes unburned ammonia from the fuel or draws a separate ammonia stream from the fuel gas supply system (FGSS) as a reducing agent to convert N2O into N2, O2, NO2, and NO through catalytic reduction. The reaction temperature is between 400 and 450°C, and the conversion rate exceeds 50%. Since the required reaction temperature may be higher than the exhaust temperature under certain operating conditions, an auxiliary heating system is needed to achieve the required reaction temperature.
[0065] The exhaust gas aftertreatment system provided in the above embodiments of the present invention employs a modified denitrification oxide reactor, arranged downstream of the nitrous oxide reactor. This modified denitrification oxide reactor has a structure with two or more layers and contains two types of catalysts. It utilizes unburned ammonia from the fuel or a separate ammonia stream drawn from the FGSS as a reducing agent, initially contacting one or more layers of pollutants (depending on the emission volume and the NO content in the exhaust gas). XThe catalyst used is a vanadium catalyst, and the last layer is a copper catalyst. The reaction temperature is 230-450℃, and the conversion rate exceeds 90%. The main reasons for this arrangement are: (1) the vanadium catalyst can ensure catalytic efficiency and extremely low N2O generation (less than 10ppm), but it will cause ammonia slip (NH3 slip); (2) therefore, the copper catalyst is arranged downstream of the vanadium catalyst, and its catalytic efficiency is similar to that of the vanadium catalyst in the reaction temperature range, although NH3 and NO X The reaction on a copper catalyst induces the production of N2O, but most of the NO is produced. X Reduced by an upstream vanadium catalyst, the copper catalyst only needs to treat a small portion of the NO. X The amount of N2O generated is negligible, and the copper catalyst has a strong ammonia storage capacity, effectively reducing the possibility of ammonia slip. Combining the two catalysts in one reactor offers advantages such as low N2O induction and low NH3 slip. The additional auxiliary heating unit mentioned above can be channeled to heat the catalyst, keeping it within the operating temperature range.
[0066] The exhaust gas aftertreatment system provided in the above embodiments of the present invention employs an ammonia oxidation catalyst reactor, with the number of oxidation catalyst layers set according to actual emissions, and placed downstream of the aforementioned nitrogen oxide removal reactor. Because ammonia is relatively difficult to burn as fuel and fluctuates greatly with load changes, it can lead to a significant amount of ammonia escape (due to afterburning, fuel ammonia); the reducing agent ammonia diverted in the FGSS may also cause some ammonia escape during load changes (due to control delay, reducing agent ammonia). The ammonia oxidation catalyst reactor is used to oxidize the escaped ammonia, converting NH3 into N2 and H2O, with a conversion rate exceeding 90%.
[0067] In situations where there are significant load variations and the use of ammonia as fuel is unavoidable, if the NH3 slip in the exhaust gas after passing through the ammonia oxidation catalyst reactor still exceeds 6 g / kWh, an ammonia fuel recovery system can be used to reduce the direct emission of ammonia vapor into the atmosphere, thus reducing environmental pollution and hazards. This ammonia fuel recovery system can achieve an ammonia fuel recovery rate of over 95%, and the liquefied ammonia fuel can be recycled again, improving fuel utilization.
[0068] The exhaust gas aftertreatment system provided in the above embodiments of the present invention includes control logic comprising:
[0069] The main pollutant in the exhaust gas source is NO. X NH3 Slip (Fuel / Reductant) and N2O;
[0070] Determine whether there is a need for purification on the current flight segment based on the actual emission restrictions and economic considerations of the flight area. If there is no need for purification, bypass discharge will proceed directly. Figure 1 Controlled by valve 1
[0071] If there is an emission requirement, proceed to the next step of the judgment logic;
[0072] Determine the combustion mode of the engine. If the engine is mainly driven by diesel, bypass the reactor for purifying N2O, controlled by valve 3, and directly enter the SCR. The ammonia channel in the FGSS, which is used as a reducing agent, is opened and controlled by valve 2, and injected quantitatively according to the purification requirements.
[0073] If diesel fuel is used to ignite NH3 or the engine is primarily powered by NH3, then further analysis of waste components is needed to determine whether escaped ammonia (fuel) is sufficient as a reducing agent to reduce N2O and NO. X If sufficient, the ammonia channel supplied by FGSS as a reducing agent is closed; if insufficient, the channel is opened and quantitative injection is carried out according to the purification requirements. The judgment logic of this channel is based on the concentration of pollutant components in the exhaust gas, and closed-loop control is performed to eliminate the uncertainty of components in the ammonia fuel combustion emission process as much as possible, and to allow the exhaust gas to pass through the nitrous oxide reactor to purify N2O, which is controlled by valve 4.
[0074] After the exhaust gas passes through the SCR reactor (provided that the SCR process removes NO), X (Ammonia escape within 10 ppm), based on the results of exhaust gas component measurements in Logic 3, if the NH3 concentration in the source discharge is lower than NO... X If the concentration is too high, the AOC is bypassed and controlled by valve 6; otherwise, the exhaust gas is allowed to pass through the AOC and controlled by valve 7.
[0075] Before the exhaust gas undergoes further treatment (emission / recovery), it enters the next level of logic control. Logic 5 is determined by the NH3 sensor. If the emission concentration is below 6g / KWh, exhaust is performed, controlled by valve 9. Otherwise, it enters the ammonia fuel recovery system, controlled by valve 10, to improve the utilization rate of ammonia and reuse the recovered ammonia as fuel ammonia or reducing agent ammonia. Other gases separated in the recovery system are discharged.
[0076] Valves 5 and 8 are used to prevent gas backflow when the corresponding reactor is bypassed.
[0077] The exhaust gas aftertreatment system provided in the above embodiments of the present invention includes three reactors arranged in a purification sequence; ammonia is used as a reducing agent to purify nitrous oxide in ship exhaust gas; the catalyst arrangement in the SCR is such that the catalyst in contact with pollutants first uses one or more layers of vanadium catalyst (V-SCR), and the last layer uses copper catalyst (Cu-SCR); ammonia is diverted through the fuel supply system as a reducing agent; ammonia with excessive concentration in the exhaust gas is recovered and then diverted back to the fuel supply system for use as fuel ammonia or reducing agent ammonia; different control logics are implemented according to different exhaust gas components, and the corresponding passages are controlled through corresponding valves.
[0078] An embodiment of the present invention provides an ammonia-fueled marine engine system, comprising: a fuel supply system, an ammonia-fueled engine, and an exhaust gas aftertreatment system of any of the above. The exhaust gas aftertreatment system is disposed at the rear end of the turbocharger of the ammonia-fueled engine and connected to the fuel supply system.
[0079] Placing the reactor equipment group in the aftertreatment system at the rear end of the turbocharger of the ammonia fuel engine allows for flexible adaptation to the layout and installation requirements of the aftertreatment system in the ship's hold for various types of ammonia fuel engines.
[0080] It should be noted that the structure of the ammonia-fueled marine engine system provided by this invention can be implemented using corresponding devices and equipment in the exhaust gas aftertreatment system. Those skilled in the art can refer to the technical solution of the exhaust gas aftertreatment system to implement the structure of the ammonia-fueled marine engine system. That is, the embodiments in the exhaust gas aftertreatment system can be understood as preferred examples of implementing the ammonia-fueled marine engine system, and will not be elaborated upon here. Other components of the ammonia-fueled marine engine system are existing technologies in the field.
[0081] The ammonia-fueled marine engine system and its exhaust aftertreatment system provided in the above embodiments of the present invention employ a synergistic treatment approach to address the main nitrogen-containing pollutants (nitric oxide, NO) in ammonia-fueled marine engines. X The system treats escaped ammonia (NH3 slip) and nitrous oxide (N2O); the equipment group in the aftertreatment system is located at the rear end of the ammonia fuel main engine turbocharger, allowing for flexible layout.
[0082] Since the combustion method of ammonia-fueled marine engines is ignition by diesel fuel, the ammonia-fueled marine engine system and its exhaust gas aftertreatment system provided in the above embodiments of the present invention fully consider this method and adopt corresponding control logic. Taking the proportion of ammonia fuel participating in combustion as the starting point, different paths are arranged for different possibilities of combustion mode and exhaust gas composition. This can significantly reduce the emission level of ammonia-fueled ships and meet the emission restrictions that ammonia-fueled marine engines currently and in the future need to face for the main nitrogen-containing pollutants.
[0083] Any matters not covered in the above embodiments of the present invention are well-known in the art.
[0084] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.
Claims
1. An exhaust gas aftertreatment system for an ammonia-fueled marine engine system, characterized in that, include: Nitrous oxide reactor, denitrification oxide reactor, ammonia oxidation catalyst reactor, and emission system; wherein: The inlet of the nitrous oxide reactor is connected to the ammonia fuel engine and the ammonia fuel supply system, respectively. The outlet of the nitrous oxide reactor is connected to the inlet of the denitrification oxide reactor. The outlet of the denitrification oxide reactor is connected to the inlet of the ammonia oxidation catalyst reactor. The outlet of the ammonia oxidation catalyst reactor is connected to the emission system. A first connecting bypass is connected between the inlet and outlet ends of the nitrous oxide reactor. A second connecting bypass is connected between the inlet and outlet ends of the ammonia oxidation catalyst reactor; According to the processing control logic, the ammonia-fueled ship engine and / or the ammonia fuel supply system are connected to the nitrous oxide reactor or connected to the denitrification oxide reactor via the first connection bypass; the denitrification oxide reactor is connected to the emission system via the ammonia oxidation catalyst reactor or connected to the emission system via the second connection bypass; The processing control logic includes: When the combustion mode of the ammonia fuel engine is mainly diesel-driven, the first connecting bypass is opened, and the ammonia fuel engine and the ammonia fuel supply system are connected to the denitrification oxide reactor through the first connecting bypass. When the combustion mode of the ammonia fuel engine is to ignite NH3 with diesel or drive the engine mainly with NH3, the first connecting bypass is controlled to close, and the ammonia fuel engine and / or the ammonia fuel supply system are connected to the nitrous oxide reactor.
2. The exhaust gas aftertreatment system for an ammonia-fueled marine engine system according to claim 1, characterized in that, The nitrous oxide reactor includes one or more layers of noble metal catalysts, which are arranged sequentially between each other. It is used to convert N2O into N2, O2, NO2 and NO by catalytic reduction using NH3 as a reducing agent.
3. The exhaust gas aftertreatment system for an ammonia-fueled marine engine system according to claim 1, characterized in that, The denitrification reactor includes one or more vanadium catalyst layers arranged sequentially and a copper catalyst layer disposed at the rear end of the vanadium catalyst layer; wherein, the vanadium catalyst layer is used to catalytically reduce NO using NH3 as a reducing agent. X The copper catalyst layer is used to convert NH3 into N2 and H2O.
4. The exhaust gas aftertreatment system for an ammonia-fueled marine engine system according to claim 1, characterized in that, The ammonia oxidation catalyst reactor includes one or more oxidation catalyst layers, which are arranged sequentially between each other to oxidize NH3 into N2 and H2O.
5. The exhaust gas aftertreatment system for an ammonia-fueled marine engine system according to claim 1, characterized in that, The emission system includes an NH3 concentration sensor and an ammonia fuel recovery system; wherein: The output of the NH3 concentration sensor is divided into two paths, one of which is connected to the ammonia fuel recovery system and the other is connected to the atmosphere. The ammonia fuel recovery system is connected to the ammonia fuel supply system; According to the emission control logic, the denitrification oxide reactor or the ammonia oxidation catalyst reactor is directly connected to the atmosphere or to the ammonia fuel recovery system through the NH3 concentration sensor.
6. The exhaust gas aftertreatment system for an ammonia-fueled marine engine system according to claim 1, characterized in that, Valves are provided on the pipeline between the nitrous oxide reactor and the denitrification oxide reactor and / or on the pipeline between the denitrification oxide reactor and the ammonia oxidation catalyst reactor to prevent gas backflow; Control valves are respectively provided at the inlet ends of the nitrous oxide reactor and the ammonia oxidation catalyst reactor, as well as on the first connecting bypass and the second connecting bypass.
7. The exhaust gas aftertreatment system for an ammonia-fueled marine engine system according to claim 1, characterized in that, Also includes: An auxiliary heating system is connected to both the nitrous oxide reactor and the denitrification oxide reactor.
8. The exhaust gas aftertreatment system for an ammonia-fueled marine engine system according to any one of claims 1-7, characterized in that, The processing control logic further includes: When the combustion mode of the ammonia fuel engine is either diesel-ignited NH3 or primarily driven by NH3, the escaped ammonia in the exhaust gas is measured to determine whether it is sufficient as a reducing agent to reduce N2O and NO. X If sufficient, the supply channel for ammonia reducing agent provided by the ammonia fuel supply system is closed; if insufficient, the supply channel for ammonia reducing agent provided by the ammonia fuel supply system is opened. When the escaped ammonia concentration output from the denitrification oxide reactor is less than or equal to a set threshold a, the escaped ammonia concentration in the exhaust gas component is measured to be less than NO. X If the concentration is positive, the second connection bypass is opened, and the denitrification oxide reactor is connected to the emission system through the second connection bypass; if not, the second connection bypass is closed, and the denitrification oxide reactor is connected to the emission system through the ammonia oxidation catalyst reactor.
9. The exhaust gas aftertreatment system for an ammonia-fueled marine engine system according to claim 5, characterized in that, The emission control logic includes: Determine whether the NH3 concentration detected by the NH3 concentration sensor is less than or equal to a set threshold b; if so, connect directly to the atmosphere; if not, connect to the ammonia fuel recovery system to reuse the recovered NH3.
10. An ammonia-fueled marine engine system, characterized in that, include: A fuel supply system, an ammonia fuel engine, and an exhaust aftertreatment system according to any one of claims 1 to 9, wherein the exhaust aftertreatment system is disposed at the rear end of the turbocharger of the ammonia fuel engine and connected to the fuel supply system.