Exhaust gas aftertreatment system and ship comprising same

Abstract

An exhaust gas aftertreatment system includes: a selective catalytic reduction device disposed on a selective catalytic reduction line; the methane oxidation catalyst device is arranged on the methane oxidation catalyst pipeline; the exhaust gas bypasses the selective catalytic reduction device and the methane oxidation catalyst device through the bypass pipeline, and the selective catalytic reduction device, the methane oxidation catalyst pipeline and the bypass pipeline are formed in parallel; and the selective catalytic reduction device and the methane oxidation catalyst device may be disposed adjacent to each other to transfer heat to each other.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0098116, filed July 27, 2023; Korean Patent Application No. 10-2023-0142169, filed October 23, 2023; and Korean Patent Application No. 10-2024-0052167, filed April 18, 2024, the entire contents of which are incorporated herein by reference as a part of this specification. Technical Field

[0003] This invention relates to an exhaust gas aftertreatment system in which a methane oxidation catalytic reaction and a selective catalytic reduction reaction occur. The invention also relates to ships incorporating such an exhaust gas aftertreatment system. Background Technology

[0004] Exhaust gases are produced when fuel is burned in an engine. These gases contain harmful substances such as nitrogen oxides, methane, and sulfur oxides, and regulations on these substances are becoming increasingly stringent. Therefore, exhaust aftertreatment systems are being researched to remove these harmful substances from exhaust gases in order to meet these emission requirements.

[0005] The aftertreatment devices for exhaust gases vary depending on the fuel. For example, when using diesel fuel, exhaust gases pass through a selective catalytic reduction unit to remove nitrogen oxides, and when using natural gas, exhaust gases pass through a methane oxidation catalyst unit to remove methane.

[0006] In recent years, ships have frequently used multiple fuels to power their engines, and some ships are equipped with both selective catalytic reduction (SCR) and methane oxidation catalyst systems. In such cases, the type of aftertreatment system for exhaust gases varies depending on the fuel used.

[0007] At this point, the compactness of the exhaust gas aftertreatment system, including a selective catalytic reduction (SCR) unit and a methane oxidation catalyst unit, is necessary to utilize the ship's internal space. Furthermore, since both the SCR and methane oxidation catalyst units actively carry out catalytic reactions at high temperatures, a continuous supply of heat to the aftertreatment system is required. Summary of the Invention

[0008] Technical issues

[0009] This invention aims to improve the utilization of ship interior space through a compact exhaust gas aftertreatment system.

[0010] Furthermore, the present invention aims to effectively utilize the heat within the exhaust gas after-treatment system.

[0011] Furthermore, the present invention aims to provide a ship including an exhaust gas aftertreatment system according to the present invention.

[0012] Technical solution

[0013] According to an embodiment of the present invention, the exhaust gas aftertreatment system includes a selective catalytic reduction (SCR) device disposed on a selective catalytic reduction (SCR) pipeline; a methane oxidation catalyst device disposed on a methane oxidation catalyst pipeline; and a bypass pipeline through which the exhaust gas bypasses the SCR device and the methane oxidation catalyst device, wherein the SCR pipeline, the methane oxidation catalyst pipeline and the bypass pipeline can be configured in parallel, and the SCR device and the methane oxidation catalyst device can be arranged adjacent to each other to enable heat transfer between them.

[0014] In the example, the bypass line may be located adjacent to at least one of the selective catalytic reduction unit or the methane oxidation catalyst unit to enable heat transfer with at least one of the selective catalytic reduction unit and the methane oxidation catalyst unit.

[0015] In the example, the system may further include a control unit that controls the flow of exhaust gas from diesel fuel through the selective catalytic reduction line or the bypass line, and controls the flow of exhaust gas from gaseous fuel through the methane oxidation catalyst line or the bypass line.

[0016] In the example, at least one area of ​​the selective catalytic reduction device, the methane oxidation catalyst device, and the bypass pipeline can be housed within a single housing.

[0017] An exhaust gas aftertreatment system according to an embodiment of the present invention includes a selective catalytic reduction (SCR) device disposed on a selective catalytic reduction (SCR) line; a methane oxidation catalyst device disposed on a methane oxidation catalyst line; and a control unit configured to control the flow of exhaust gas generated from diesel fuel through the SCR line and to control the flow of exhaust gas generated from gaseous fuel through the methane oxidation catalyst line, wherein the SCR line and the methane oxidation catalyst line are configured in parallel, and the SCR device and the methane oxidation catalyst device are disposed adjacent to each other to enable heat transfer between them, and the control unit can control the flow of exhaust gas through the SCR line when bypassing exhaust gas generated from the gaseous fuel.

[0018] In the example, the selective catalytic reduction device and the methane oxidation catalyst device can be housed in a single housing.

[0019] An exhaust gas aftertreatment system according to an embodiment of the present invention includes a selective catalytic reduction (SCR) device disposed on a main exhaust gas line; a methane oxidation catalyst device disposed downstream of the SCR device on the main exhaust gas line; and a first bypass line configured to branch off from the main exhaust gas line between the SCR device and the methane oxidation catalyst device and to bypass the methane oxidation catalyst device, wherein the methane oxidation catalyst device and the first bypass line may be disposed adjacent to each other to allow heat transfer between them.

[0020] In the example, the system may further include a second bypass line configured to branch off from the main exhaust gas line upstream of the selective catalytic reduction unit and to bypass the selective catalytic reduction unit.

[0021] In the example, the system may further include a control unit configured to control the flow of exhaust gas from diesel fuel through the selective catalytic reduction device via the first bypass line, and to control the flow of exhaust gas from gaseous fuel through the selective catalytic reduction device via the methane oxidation catalyst device or the first bypass line.

[0022] In the example, the system may further include a control unit configured to control the flow of exhaust gas from diesel fuel through the selective catalytic reduction unit or the second bypass line through the first bypass line, and to control the flow of exhaust gas from gaseous fuel through the selective catalytic reduction unit or the second bypass line through the methane oxidation catalyst unit or the first bypass line.

[0023] In the example, the methane oxidation catalyst device and at least one area of ​​the first bypass line can be housed within a single housing.

[0024] In the example, the methane oxidation catalyst device and at least one area of ​​the first bypass pipeline can be housed in a single housing, or the selective catalytic reduction device and at least one area of ​​the second bypass pipeline can be housed in a single housing.

[0025] Ships may include exhaust gas aftertreatment systems according to embodiments of the present invention.

[0026] Beneficial effects

[0027] According to the present invention, the utilization of the ship's internal space can be improved through a compact exhaust gas aftertreatment system.

[0028] This invention can effectively utilize the heat within the exhaust gas after-treatment system. Attached Figure Description

[0029] Figure 1 This is a diagram illustrating an exhaust gas aftertreatment system according to a first embodiment of the present invention.

[0030] Figure 2 This is a diagram illustrating the specific configuration of an exhaust gas aftertreatment system according to a first embodiment of the present invention.

[0031] Figure 3 This is a diagram illustrating an exhaust gas aftertreatment system according to a second embodiment of the present invention.

[0032] Figure 4 This is a diagram illustrating an exhaust gas aftertreatment system according to a third embodiment of the present invention. Detailed Implementation

[0033] Some embodiments of the present invention will now be described in detail with reference to the exemplary accompanying drawings. When assigning reference numerals to components in each drawing, it should be noted that the same components are labeled as often as possible, even when they reappear in other drawings. Furthermore, in describing embodiments of the invention, detailed descriptions of related known structures or functions will be omitted if they are determined to impede understanding of the embodiments of the invention.

[0034] Furthermore, when describing components of embodiments of the present invention, terms such as "first," "second," "A," "B," "(a)," and "(b)" may be used. These terms are used only to distinguish a component from other components, and the nature, order, or sequence of components is not limited by these terms. When a component is described as "connecting," "linking," or "accessing" another component, it should be understood that the component may directly connect to or access the other component, but other components may also be "connected," "linked," or "accessed" between the respective components.

[0035] In this specification, the terms "front-back direction," "left-right direction," and "up-down direction" are used for convenience of interpretation and may be directions orthogonal to each other. However, these directions are defined relative to each other, and "up-down" direction may not necessarily mean a perpendicular direction.

[0036] <First Embodiment>

[0037] Figure 1 This is a diagram illustrating an exhaust gas aftertreatment system according to a first embodiment of the present invention.

[0038] Figure 2 This is a diagram illustrating the specific configuration of an exhaust gas aftertreatment system according to a first embodiment of the present invention.

[0039] refer to Figure 1According to a first embodiment of the present invention, the exhaust gas aftertreatment system 1 includes a selective catalytic reduction (SCR) device 10 disposed on a selective catalytic reduction (SCR) line L1; a methane oxidation catalyst device 20 disposed on a methane oxidation catalyst line L2; and a bypass line BL through which exhaust gas is bypassed without passing through the SCR device 10 and the methane oxidation catalyst device 20. The SCR line L1, the methane oxidation catalyst line L2, and the bypass line BL are configured in parallel, and the SCR device 10 and the methane oxidation catalyst device 20 are disposed adjacent to each other to allow for heat transfer between them. Each component will be described in detail below.

[0040] The selective catalytic reduction (SCR) unit 10 is a device that uses a reducing agent and a denitrification catalyst to react nitrogen oxides contained in exhaust gas with each other to reduce them to nitrogen and water, which are harmless to humans, and then discharges the reduced nitrogen oxides. The control unit 100 controls the exhaust gas produced by the diesel fuel engine to remove nitrogen oxides as it passes through the SCR unit 10 on the SCR line L1. At this time, a device for supplying the reducing agent can be provided upstream of the SCR unit 10. For example, a urea-water (ammonia) injector and mixer can be used to supply the reducing agent to the SCR unit 10.

[0041] For example, the control unit 100 opens the valve 30 upstream of the selective catalytic reduction device 10 and closes the valve 50 on the bypass line and the valve 40 upstream of the methane oxidation catalyst device 20, thereby controlling the flow of exhaust gas generated by the diesel fuel engine along the selective catalytic reduction line L1.

[0042] The methane oxidation catalyst unit 20 is a device for oxidizing and removing methane contained in exhaust gas. The control unit 100 controls the exhaust gas generated by the natural gas engine to remove methane as it passes through the methane oxidation catalyst unit 20 on the methane oxidation catalyst line L2.

[0043] For example, the control unit 100 opens the valve 40 upstream of the methane oxidation catalyst unit 20 and closes the valve 50 on the bypass line and the valve 30 upstream of the selective catalytic reduction unit 10, thereby controlling the flow of exhaust gas generated by the natural gas engine along the methane oxidation catalyst line L2.

[0044] Furthermore, when the exhaust gas is not subjected to a post-treatment process, or when only some of the exhaust gas is subjected to a post-treatment process, the control unit 100 can control at least some of the exhaust gas to bypass the selective catalytic reduction unit 10 and the methane oxidation catalyst unit 20 and flow along the bypass line BL.

[0045] For example, control unit 100 can open valve 50 on bypass line BL and close valve 40 upstream of methane oxidation catalyst unit 20 and valve 30 upstream of selective catalytic reduction unit 10, thereby controlling the flow of all exhaust gas along bypass line BL. Control unit 100 can also close valve 40 upstream of methane oxidation catalyst unit 20 and control valves 30 and 50, so that some of the exhaust gas flows to selective catalytic reduction unit 10 and others flows to bypass line BL.

[0046] The selective catalytic reduction line L1, the methane oxidation catalyst line L2, and the bypass line BL are configured in parallel, and therefore the exhaust gas passing through one line cannot pass through other lines.

[0047] The selective catalytic reduction (SCR) unit 10 and the methane oxidation catalyst unit 20 are arranged adjacent to each other to allow heat transfer between them. This is not only to improve the utilization of the ship's internal space, but also to allow heat generated by the aftertreatment unit where exhaust gases pass and react to be transferred to the aftertreatment unit where exhaust gases do not pass and do not react. For example, when exhaust gases are generated using diesel fuel, the exhaust gases pass through the SCR unit 10 along the SCR line L1. At this time, the temperature of the SCR unit 10 rises due to the exothermic catalytic reaction. This heat is transferred to the adjacent methane oxidation catalyst unit 20, where exhaust gases do not pass and do not react, thereby preheating the methane oxidation catalyst unit 20. When gaseous fuel is subsequently used and exhaust gases pass through the methane oxidation catalyst unit 20, the preheating of the methane oxidation catalyst unit 20 may reduce the initial heat required for the methane oxidation catalyst reaction.

[0048] In contrast to the previous example, the selective catalytic reduction unit 10 can be preheated by the catalytic reaction occurring in the methane oxidation catalyst unit 20. This improves the thermal efficiency of the entire exhaust gas aftertreatment system 1.

[0049] The bypass line BL may also be located adjacent to at least one of the selective catalytic reduction unit 10 and the methane oxidation catalyst unit 20, allowing for heat transfer with at least one of them. This is not only to improve the utilization of the ship's internal space, but also to allow heat generated in the aftertreatment unit through which exhaust gases have passed and reacted to be transferred to the bypass line BL where the exhaust gases have not passed, or to allow heat from exhaust gases bypassed via the bypass line BL to be transferred to the aftertreatment unit where the exhaust gases have not passed and have not reacted.

[0050] When the exhaust gas does not pass through the bypass line BL, there is a risk of low-temperature corrosion, and the temperature inside the bypass line BL drops. Therefore, if the heat generated in the after-treatment device where the exhaust gas passes and reacts is transferred to the bypass line BL where the exhaust gas does not pass, low-temperature corrosion can be prevented.

[0051] If the heat of the exhaust gas flowing through the bypass line BL is transferred to the selective catalytic reduction unit 10 or the methane oxidation catalyst unit 20, in which the exhaust gas has not passed and has not reacted, the selective catalytic reduction unit 10 or the methane oxidation catalyst unit 20 is preheated as described above to improve the thermal efficiency of the entire exhaust gas aftertreatment system 1.

[0052] At least one area of ​​the selective catalytic reduction unit 10, the methane oxidation catalyst unit 20, and the bypass line BL can be housed within a single housing 80. This arrangement within the single housing 80 allows for partial preheating using the heat from the exhaust gas, thereby saving energy required for preheating and shortening the preheating time, and thus further improving the overall thermal efficiency of the exhaust gas aftertreatment system 1.

[0053] like Figure 2 As shown in (a), the bypass line BL may be located adjacent to each of the selective catalytic reduction unit 10 and the methane oxidation catalyst unit 20 and between the selective catalytic reduction unit 10 and the methane oxidation catalyst unit 20. Figure 2 As shown in (b), the selective catalytic reduction unit 10 and the methane oxidation catalyst unit 20 are directly adjacent to each other, and the bypass line BL may be arranged adjacent to them. However, this is merely an exemplary example of the exhaust gas aftertreatment system 1 according to the first embodiment of the present invention, and is not limited thereto.

[0054] <Second Embodiment>

[0055] Figure 3 This is a diagram illustrating an exhaust gas aftertreatment system according to a second embodiment of the present invention.

[0056] Reference Figure 3According to a second embodiment of the present invention, the exhaust gas aftertreatment system 1 includes a selective catalytic reduction (SCR) device 10 disposed on a selective catalytic reduction (SCR) line L1; a methane oxidation catalyst device 20 disposed on a methane oxidation catalyst line L2; and a control unit 100 that controls the flow of exhaust gas generated from diesel fuel through the SCR line L1 and controls the flow of exhaust gas generated from gaseous fuel through the methane oxidation catalyst line L2, wherein the SCR line L1 and the methane oxidation catalyst line L2 are configured in parallel, the SCR device 10 and the methane oxidation catalyst device 20 are arranged adjacent to each other to enable heat transfer therebetween, and the control unit 100 controls the flow of exhaust gas through the SCR line L1 when bypassing exhaust gas generated from gaseous fuel. The differences from the first embodiment will be mainly described below.

[0057] According to the second embodiment of the present invention, the exhaust gas aftertreatment system 1 does not have a separate bypass line, and the selective catalytic reduction line L1 is used as a bypass line for the methane oxidation catalyst line L2.

[0058] The control unit 100 is similar to the first embodiment 1 in that it controls the exhaust gas generated by the diesel fuel engine to remove nitrogen oxides when passing through the selective catalytic reduction device 10 on the selective catalytic reduction line L1, and controls the exhaust gas generated by the natural gas engine to remove methane when passing through the methane oxidation catalyst device 20 on the methane oxidation catalyst line L2.

[0059] However, a difference arises when the exhaust gas from the natural gas engine does not pass through the methane oxidation catalyst unit 20, or when only some of the exhaust gas passes through the methane oxidation catalyst unit 20. The control unit 100 can control at least some of the exhaust gas to flow along the selective catalytic reduction line L1, bypassing the methane oxidation catalyst unit 20. That is, the selective catalytic reduction line L1 can be a bypass line to the methane oxidation catalyst line L2.

[0060] For example, when the exhaust gas from the natural gas engine can be directly discharged into the atmosphere without passing through the methane oxidation catalyst unit 20, the control unit 100 can open the valve 30 upstream of the selective catalytic reduction unit 10 and close the valve 40 upstream of the methane oxidation catalyst unit 20 to control the flow of the exhaust gas from the natural gas engine along the selective catalytic reduction pipeline L1. This is possible because even when the exhaust gas from the natural gas engine passes through the selective catalytic reduction unit 10, there is no problem of the catalyst used for the selective catalytic reduction reaction becoming contaminated or losing its function. However, since the methane oxidation catalyst may lose its function when it comes into contact with the exhaust gas from the diesel engine, it is not possible to control the flow of the exhaust gas from the diesel fuel engine along the methane oxidation catalyst pipeline L2.

[0061] The selective catalytic reduction unit 10 and the methane oxidation catalyst unit 20 can be arranged adjacent to each other to enable heat transfer between them. As mentioned above, this not only promotes the utilization of the ship's internal space, but also improves the thermal efficiency of the entire exhaust gas aftertreatment system 1 by preheating the exhaust gas aftertreatment unit in which the aftertreatment reaction occurs.

[0062] The selective catalytic reduction unit 10 and the methane oxidation catalyst unit 20 can be housed within a single housing 80. This arrangement allows for partial preheating using the heat from the exhaust gas, thereby saving energy required for preheating, shortening preheating time, improving heat transfer efficiency, and thus further enhancing the overall thermal efficiency of the exhaust gas aftertreatment system 1.

[0063] <Third Embodiment>

[0064] Figure 4 This is a diagram illustrating an exhaust gas aftertreatment system according to a third embodiment of the present invention.

[0065] Reference Figure 4 According to a third embodiment of the present invention, the exhaust gas aftertreatment system 1 includes a selective catalytic reduction device 10 disposed on the main exhaust gas line ML; a methane oxidation catalyst device 20 disposed on the main exhaust gas line ML downstream of the selective catalytic reduction device 10; and a first bypass line BL1, which branches off from the main exhaust gas line ML between the selective catalytic reduction device 10 and the methane oxidation catalyst device 20 and is used to bypass the methane oxidation catalyst device 20, wherein the methane oxidation catalyst device 20 and the first bypass line BL1 are disposed adjacent to each other to allow heat transfer between them. Each component will be described in detail below.

[0066] Unlike the first and second embodiments, in the exhaust gas aftertreatment system 1 according to the third embodiment of the present invention, the selective catalytic reduction device 10 and the methane oxidation catalyst device 20 are connected in series. Therefore, the exhaust gas after passing through the selective catalytic reduction device 10 can further pass through the methane oxidation catalyst device 20.

[0067] Nitrogen oxides are removed from the exhaust gas produced by the diesel engine as it passes through the selective catalytic reduction unit 10, and the exhaust gas bypasses the methane oxidation catalyst unit 20 via the first bypass line BL1 after passing through the selective catalytic reduction unit 10. This is because, as mentioned above, if the methane oxidation catalyst comes into contact with the exhaust gas produced by the diesel engine, there is a risk that the methane oxidation catalyst will lose its function.

[0068] For example, the control unit 100 can open the valve 30 upstream of the selective catalytic reduction unit 10 and control the exhaust gas generated by the diesel fuel engine to pass through the selective catalytic reduction unit 10. Then, the control unit 100 can close the valve 40 upstream of the methane oxidation catalyst unit 20 and open the valve 60 on the first bypass line BL1 to control the exhaust gas generated by the diesel fuel engine to bypass the methane oxidation catalyst unit 20.

[0069] The exhaust gas from the gas-fueled engine passes through the selective catalytic reduction unit 10 and then enters the methane oxidation catalytic unit 20, where methane is removed through a methane oxidation catalytic reaction. Since the catalyst in the selective catalytic reduction unit 10 does not risk losing its function even when in contact with the exhaust gas from the gas-fueled engine, the exhaust gas does not need to bypass the selective catalytic reduction unit 10.

[0070] For example, control unit 100 can open valve 30 upstream of selective catalytic reduction unit 10 and control the exhaust gas generated by the gas fuel engine to pass through selective catalytic reduction unit 10. Then, control unit 100 can open valve 40 upstream of methane oxidation catalyst unit 20 and close valve 60 on the first bypass line BL1 to control the exhaust gas generated by the gas fuel engine to pass through methane oxidation catalyst unit 20. If necessary, control unit 100 can control valves 40 and 60 so that at least some of the exhaust gas generated by the gas fuel engine flows through the first bypass line BL1.

[0071] In addition, the exhaust gas aftertreatment system 1 according to the third embodiment of the present invention may further include a second bypass line BL2, which branches off from the exhaust gas main line ML upstream of the selective catalytic reduction device 10 and is used to bypass the selective catalytic reduction device 10.

[0072] When the exhaust gas is not post-treated, or when only some of the exhaust gas is post-treated, the control unit 100 can control at least some of the exhaust gas to bypass the selective catalytic reduction device 10 and the methane oxidation catalyst device 20 and flow along the second bypass line BL2 and the first bypass line BL1.

[0073] For example, the control unit 100 can close the valve 30 upstream of the selective catalytic reduction unit 10 and open the valve 70 on the second bypass line BL2 to control the flow of exhaust gas along the second bypass line BL2. Furthermore, the control unit 100 can close the valve 40 upstream of the methane oxidation catalyst unit 20 and open the valve 60 on the first bypass line BL1 to control the flow of exhaust gas along the first bypass line BL1.

[0074] The selective catalytic reduction unit 10 and the second bypass line BL2, as well as the methane oxidation catalyst unit 20 and the first bypass line BL1, can be arranged adjacent to each other to enable heat transfer between them. This not only promotes the utilization of the ship's internal space, but also improves the thermal efficiency of the entire exhaust gas aftertreatment system 1 by preventing low-temperature corrosion of the bypass line and preheating of the aftertreatment device.

[0075] The methane oxidation catalyst unit 20 and at least one area of ​​the first bypass line BL1 can be housed within a single housing, or the selective catalytic reduction unit 10 and at least one area of ​​the second bypass line BL2 can be housed within a single housing 80. Housed within a single housing 80, they allow for partial preheating using the heat of the exhaust gas, thereby saving energy required for preheating and shortening preheating time, thus improving heat transfer efficiency and further enhancing the overall thermal efficiency of the exhaust gas aftertreatment system 1.

[0076] Additionally, the ship may include an exhaust gas aftertreatment system 1 according to an embodiment of the present invention.

[0077] The above description is merely an exemplary description of the technical concept of the present invention, and therefore those skilled in the art can make various modifications and changes without departing from the essential characteristics of the invention. Therefore, the embodiments disclosed in this invention are not intended to limit but rather to describe the technical concept of the invention, and the scope of the technical concept of the invention is not limited to these embodiments. It should be understood that the scope of protection of the present invention is defined by the following claims, and all technical concepts within their equivalent scope are included within the scope of the claims of the present invention.

Claims

1. Exhaust gas after-treatment system, including: A selective catalytic reduction device, wherein the selective catalytic reduction device is installed on a selective catalytic reduction pipeline; A methane oxidation catalyst device, wherein the methane oxidation catalyst device is installed on a methane oxidation catalyst pipeline; and The waste gas bypasses the selective catalytic reduction unit and the methane oxidation catalyst unit via the bypass pipeline. The selective catalytic reduction line, the methane oxidation catalyst line, and the bypass line are configured in parallel, and The selective catalytic reduction device and the methane oxidation catalyst device are arranged adjacent to each other to enable heat transfer between them.

2. The waste gas after-treatment system according to claim 1, in, The bypass line is located adjacent to at least one of the selective catalytic reduction unit or the methane oxidation catalyst unit to enable heat transfer with at least one of the selective catalytic reduction unit and the methane oxidation catalyst unit.

3. The exhaust gas aftertreatment system according to claim 1, further comprising: Control unit, the control unit is configured to Controlling the flow of exhaust gas from diesel fuel through the selective catalytic reduction line or the bypass line, and Control the flow of exhaust gas generated from gaseous fuel through the methane oxidation catalyst pipeline or the bypass pipeline.

4. The waste gas after-treatment system according to claim 1, The selective catalytic reduction device, the methane oxidation catalyst device, and at least one area of ​​the bypass pipeline are housed within a single housing.

5. Exhaust gas after-treatment system, including: A selective catalytic reduction device, wherein the selective catalytic reduction device is installed on a selective catalytic reduction pipeline; A methane oxidation catalyst device, wherein the methane oxidation catalyst device is installed on a methane oxidation catalyst pipeline; and A control unit configured to control the flow of exhaust gas from diesel fuel through the selective catalytic reduction line and to control the flow of exhaust gas from gaseous fuel through the methane oxidation catalyst line; The selective catalytic reduction line and the methane oxidation catalyst line are configured in parallel, and the selective catalytic reduction unit and the methane oxidation catalyst unit are arranged adjacent to each other to enable heat transfer between them. When bypassing the exhaust gas generated from the gaseous fuel, the control unit controls the exhaust gas to flow through the selective catalytic reduction pipeline.

6. The waste gas after-treatment system according to claim 5, The selective catalytic reduction device and the methane oxidation catalyst device are housed in a single housing.

7. Exhaust gas after-treatment system, including: A selective catalytic reduction device, wherein the selective catalytic reduction device is installed on the main exhaust gas line; A methane oxidation catalyst device, wherein the methane oxidation catalyst device is located on the main exhaust gas line downstream of the selective catalytic reduction device; and A first bypass line is configured to branch off from the main exhaust gas line between the selective catalytic reduction unit and the methane oxidation catalyst unit and to bypass the methane oxidation catalyst unit. The methane oxidation catalyst device and the first bypass pipeline are arranged adjacent to each other to enable heat transfer between them.

8. The exhaust gas aftertreatment system according to claim 7, further comprising: A second bypass line is configured to branch off from the main exhaust gas line upstream of the selective catalytic reduction unit and to bypass the selective catalytic reduction unit.

9. The exhaust gas aftertreatment system according to claim 7, further comprising: Control unit, the control unit is configured to The exhaust gas generated from diesel fuel is controlled to flow through the first bypass line via the selective catalytic reduction device, and The exhaust gas generated from the gaseous fuel is controlled to flow through the methane oxidation catalyst unit or the first bypass line via the selective catalytic reduction unit.

10. The exhaust gas aftertreatment system according to claim 8, further comprising: Control unit, the control unit is configured to Controlling the flow of exhaust gas generated from diesel fuel through the selective catalytic reduction unit or the second bypass line through the first bypass line, and The exhaust gas generated from the gaseous fuel is controlled to flow through the methane oxidation catalyst device or the first bypass line via the selective catalytic reduction device or the second bypass line.

11. The waste gas after-treatment system according to claim 7, The methane oxidation catalyst device and at least one area of ​​the first bypass line are housed within a single housing.

12. The waste gas after-treatment system according to claim 8, The methane oxidation catalyst device and at least one area of ​​the first bypass pipeline are disposed within a single housing, or the selective catalytic reduction device and at least one area of ​​the second bypass pipeline are disposed within a single housing.

13. A ship, comprising an exhaust gas aftertreatment system according to any one of claims 1 to 12.

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