Exhaust gas aftertreatment system and ship having same

Abstract

This exhaust gas aftertreatment system comprises: a multi-fuel engine configured to selectively use two or more different types of fuel; and a catalyst chamber disposed downstream of the multi-fuel engine and including an upstream catalyst and a downstream catalyst located downstream of the upstream catalyst.

Description

Exhaust gas aftertreatment system and vessel including same

[0001] Cross-citation with 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, Korean Patent Application No. 10-2024-0052158, filed April 18, 2024, Korean Patent Application No. 10-2024-0052159, filed April 18, 2024, and Korean Patent Application No. 10-2024-0052160, filed April 18, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to an exhaust gas aftertreatment system and a ship including the same.

[0005] Ships include multi-fuel engines that use two or more different types of fuel, such as gaseous fuel (natural gas, methane, etc.) and liquid fuel (diesel fuel).

[0006] Gaseous fuel contains methane, and methane exists in a fairly stable state due to its strong carbon-hydrogen bonds. Therefore, if it is not completely consumed in the engine and is emitted, it is not naturally oxidized under exhaust gas temperature conditions and is emitted into the atmosphere in an untreated state.

[0007] Meanwhile, methane (CH4) is a global warming substance that exhibits a stronger greenhouse effect than an equivalent amount of carbon dioxide (CO2). To address the problem of global warming, the amount of methane emitted from exhaust gases must be reduced. Recently, with the International Maritime Organization (IMO) and the European Union (EU) strengthening regulations to reduce GHG (global warming gases) emissions, GHG emission regulations such as carbon dioxide (CO2) and carbon taxes are being discussed, and technology that prevents methane from being released into the atmosphere is required. In response to this demand, various studies are being conducted to efficiently purify the exhaust gases of multi-fuel engines, which are a major cause of environmental pollution, and in particular, to efficiently remove methane contained in large quantities in exhaust gases.

[0008] Marine exhaust gas aftertreatment systems utilize methane oxidation catalysts (MOCs) to efficiently remove methane. Methane oxidation catalysts can only achieve optimal performance when their temperature is higher than the exhaust gas temperature. Furthermore, methane oxidation catalysts can be easily degraded by sulfur oxides and hydrocarbons.

[0009] The information contained in this background section is intended to enhance understanding of the background of the invention and may include matters that are not prior art and are already known to those of ordinary skill in the art.

[0010] The present invention has been conceived in consideration of the above points, and its purpose is to provide an exhaust gas aftertreatment system and a ship including the same, which can extend the service life of a methane oxidation catalyst by reducing or removing sulfur oxides, hydrocarbons, etc. contained in exhaust gas in advance by a diesel oxidation catalyst before the exhaust gas comes into contact with the methane oxidation catalyst.

[0011] In addition, the present invention aims to provide an exhaust gas aftertreatment system and a ship including the same, in which an injector mechanism is configured to inject an oxidizable substance (diesel fuel, urea, etc.) to an upstream catalyst, thereby inducing temperature increase of a downstream catalyst and improving methane reduction efficiency by the downstream catalyst.

[0012] And, the purpose of the present invention is to provide an exhaust gas post-treatment system capable of improving the regeneration efficiency of a catalyst that removes harmful substances from exhaust gas, and a ship including the same.

[0013] The problem to be solved in the embodiment is not limited to this, and it can be said that the purpose or effect that can be understood from the solution or implementation form of the problem described below is also included.

[0014] In order to achieve the above object, an exhaust gas aftertreatment system according to an embodiment of the present invention may include: a multi-fuel engine configured to selectively use two or more different types of fuel; and a catalyst chamber disposed downstream of the multi-fuel engine and including an upstream catalyst and a downstream catalyst positioned downstream of the upstream catalyst. The upstream catalyst may be at least one catalyst selected from among a diesel oxidation catalyst and a methane oxidation catalyst, or a combination thereof, and the downstream catalyst may be at least one catalyst selected from among a methane oxidation catalyst and a diesel oxidation catalyst, or a combination thereof.

[0015] According to one embodiment, the catalyst composition content of the upstream catalyst may be relatively greater than the catalyst composition content of the downstream catalyst.

[0016] In one embodiment, the precious metal content of the upstream catalyst may be relatively higher than the precious metal content of the downstream catalyst.

[0017] The above catalyst chamber may be located downstream of the turbocharger.

[0018] The exhaust gas aftertreatment system according to an embodiment of the present invention may further include an inlet-side exhaust gas line connected from the multi-fuel engine to the inlet of the catalyst chamber, and an outlet-side exhaust gas line connected to the outlet of the catalyst chamber. The exhaust gas aftertreatment system for a ship according to an embodiment of the present invention may further include an inlet-side valve arranged in the inlet-side exhaust gas line, and an outlet-side valve arranged in the outlet-side exhaust gas line.

[0019] The exhaust gas aftertreatment system according to an embodiment of the present invention may further include a bypass line branched from the inlet exhaust gas line and joined to the outlet exhaust gas line so that exhaust gas discharged from the multi-fuel engine bypasses the catalyst chamber.

[0020] The exhaust gas aftertreatment system according to an embodiment of the present invention may further include a bypass valve disposed in the bypass line.

[0021] The above catalyst chamber may be located upstream of the turbocharger.

[0022] An exhaust gas aftertreatment system according to an embodiment of the present invention may further include an inlet-side exhaust gas line connected from the multi-fuel engine to the inlet of the catalyst chamber, and an outlet-side exhaust gas line connected from the outlet of the catalyst chamber to the inlet of the turbine of the turbocharger.

[0023] An exhaust gas aftertreatment system according to an embodiment of the present invention may include: a multi-fuel engine configured to selectively use two or more different types of fuel; a catalyst chamber disposed downstream of the multi-fuel engine and including an upstream catalyst and a downstream catalyst positioned downstream of the upstream catalyst; an injector mechanism configured to inject an oxidizable substance to the upstream catalyst upstream of the upstream catalyst; and a controller controlling the injector mechanism.

[0024] The above injector mechanism may be a diesel injector mechanism configured to inject diesel fuel into the upstream catalyst.

[0025] The above diesel injector device may include a diesel injector that injects diesel fuel into the upstream catalyst, and a fuel pump unit that supplies diesel fuel to the diesel injector.

[0026] The above controller can control the fuel pump unit to determine the amount of diesel fuel injected by the diesel injector based on the target temperature of the downstream catalyst.

[0027] The above injector mechanism may be a urea injector mechanism configured to inject urea into the upstream catalyst.

[0028] The above urea injector device may include a urea injector that injects urea into the upstream catalyst, and a urea dosing unit fluidly connected to the urea injector through a urea line.

[0029] The above controller can control the urea dosing unit to determine the injection amount of urea by the urea injector based on the target temperature of the downstream catalyst.

[0030] An exhaust gas aftertreatment system according to an embodiment of the present invention may further include an inlet-side exhaust gas line connected from the multi-fuel engine to the inlet of the catalyst chamber, and an outlet-side exhaust gas line connected to the outlet of the catalyst chamber.

[0031] The exhaust gas aftertreatment system according to an embodiment of the present invention may further include an inlet valve arranged in the inlet exhaust gas line and an outlet valve arranged in the outlet exhaust gas line.

[0032] The exhaust gas aftertreatment system according to an embodiment of the present invention may further include a bypass line branched from the inlet exhaust gas line and joined to the outlet exhaust gas line so that exhaust gas discharged from the multi-fuel engine bypasses the catalyst chamber.

[0033] The exhaust gas aftertreatment system according to an embodiment of the present invention may further include a bypass valve disposed in the bypass line.

[0034] The above controller may be configured to control the injector mechanism, the inlet valve, the outlet valve, and the bypass valve depending on the temperature of the downstream catalyst and whether gas strip occurs.

[0035] An exhaust gas aftertreatment system according to an embodiment of the present invention may include: a multi-fuel engine configured to selectively use two or more different types of fuel; a catalyst chamber disposed downstream of the multi-fuel engine and including an upstream catalyst and a downstream catalyst located downstream of the upstream catalyst; and a regeneration gas supply device configured to supply regeneration gas to an inlet of the catalyst chamber.

[0036] The above regeneration gas may include a reducing agent and an inert gas.

[0037] The above regeneration gas supply device supplies a reducing agent It may include a supply unit and an inert gas supply unit that supplies an inert gas.

[0038] The exhaust gas aftertreatment system according to an embodiment of the present invention may further include an inlet-side exhaust gas line connected to the inlet of the catalyst chamber. The reducing agent The supply unit is a reducing agent Fluidically connected to the inlet exhaust gas line through the supply line, and the reducing agent The source of the above reducing agent It can be located upstream of the supply unit.

[0039] The above inert gas The supply unit is an inert gas Fluidically connected to the inlet exhaust gas line through the supply line, and inert gas The supply source may be located upstream of the inert gas supply unit.

[0040] The above inert gas The supply unit may further include a heater configured to heat the inert gas.

[0041] The above reducing agent Supply line and the above inert gas The supply line can be joined to the inlet of the regeneration gas supply line, and the outlet of said regeneration gas supply line can be fluidly connected to a portion of said inlet-side exhaust gas line adjacent to said catalyst chamber.

[0042] The exhaust gas aftertreatment system according to an embodiment of the present invention may further include a water injector mechanism configured to inject water to the downstream catalyst.

[0043] The above water injector mechanism can be placed downstream of the downstream catalyst in the internal space of the catalyst chamber.

[0044] The above water injector device may include a water pipe arranged downstream of the downstream catalyst, and a plurality of water injectors arranged from the water pipe toward the downstream catalyst.

[0045] A vessel according to an embodiment of the present invention may include an exhaust gas aftertreatment system according to the above-described embodiment.

[0046] According to the present invention, as the exhaust gas first reacts with the upstream catalyst, an exothermic reaction may occur in the upstream catalyst, and as a result, the temperature of the internal space of the catalyst chamber may relatively increase, and as a result, the temperature of the downstream catalyst increases, and the downstream catalyst can more effectively remove methane contained in the exhaust gas (i.e., the reactivity of the downstream catalyst increases at high temperatures).

[0047] According to the present invention, the upstream catalyst can be configured to have a relatively smaller size than the downstream catalyst, and thus, when the upstream catalyst, which comes into contact with the exhaust gas first, deteriorates in performance by removing hydrocarbons and sulfur in advance, the work of replacing only the upstream catalyst can be easy, and the cost of replacing the upstream catalyst can be made relatively low.

[0048] According to the present invention, the content of the catalyst composition of the upstream catalyst may be relatively greater than that of the downstream catalyst, and thus, an exothermic reaction may be induced in the upstream catalyst during the process in which the exhaust gas reacts with the upstream catalyst. This allows the temperature of the internal space of the catalyst chamber to relatively rise, and since the temperature of the downstream catalyst rises higher than the temperature of the exhaust gas, the downstream catalyst can more effectively remove methane contained in the exhaust gas.

[0049] According to the present invention, the precious metal content of the upstream catalyst can be relatively higher than that of the downstream catalyst, and thus, the performance of the upstream catalyst is not reduced or minimized due to hydrocarbon poisoning, sulfur poisoning, etc., and an exothermic reaction can be induced in the upstream catalyst during the process in which the exhaust gas reacts with the upstream catalyst. Through this, the temperature of the internal space of the catalyst chamber can relatively increase, and since the temperature of the downstream catalyst is higher than the temperature of the exhaust gas, the downstream catalyst can more effectively remove methane contained in the exhaust gas. For example, when the upstream catalyst is configured as a diesel oxidation catalyst and the downstream catalyst is configured as a methane oxidation catalyst in the catalyst chamber, sulfur oxides, hydrocarbons, etc. contained in the exhaust gas can be removed in advance before the exhaust gas comes into contact with the methane oxidation catalyst, and thereby the service life of the methane oxidation catalyst can be extended.

[0050] According to the present invention, by injecting an oxidizable substance (diesel fuel, urea, etc.) to an upstream catalyst through an injector mechanism, the oxidizable substance can react with the upstream catalyst and be oxidized, and the temperature of exhaust gas passing through the upstream catalyst can be increased through oxidation of the oxidizable substance, thereby inducing an increase in the temperature of the downstream catalyst and an increase in the temperature of the internal space of the catalyst chamber, and the methane reduction efficiency by the downstream catalyst can be significantly improved.

[0051] According to the present invention, the regeneration efficiency of the catalyst in the catalyst chamber can be improved by supplying the regeneration gas to the inlet of the catalyst chamber by the regeneration gas supply device.

[0052] According to the present invention, since the water injector mechanism directly injects water onto the downstream catalyst, the adsorbent attached to the downstream catalyst can be smoothly washed away, thereby enabling the downstream catalyst to be smoothly regenerated.

[0053] FIG. 1 is a drawing schematically illustrating the overall structure of an exhaust gas aftertreatment system according to an embodiment of the present invention.

[0054] FIG. 2 is a drawing illustrating a catalyst arrangement structure arranged in the internal space of a catalyst chamber of an exhaust gas aftertreatment system according to one embodiment of the present invention.

[0055] FIG. 3 is a drawing illustrating a catalyst arrangement structure arranged in the internal space of a catalyst chamber of an exhaust gas aftertreatment system according to another embodiment of the present invention.

[0056] FIG. 4 is a drawing showing a diesel injector mechanism mounted in a catalyst chamber of an exhaust gas aftertreatment system according to one embodiment of the present invention and a water injection mechanism arranged within the catalyst chamber.

[0057] FIG. 5 is a drawing showing a diesel injector mechanism mounted in a catalyst chamber of an exhaust gas aftertreatment system according to another embodiment of the present invention and a water injection mechanism arranged within the catalyst chamber.

[0058] FIG. 6 is a drawing illustrating a diesel injector device mounted on an exhaust gas line at the inlet side of an exhaust gas aftertreatment system according to one embodiment of the present invention and a water injection device positioned within a catalyst chamber.

[0059] FIG. 7 is a drawing showing a diesel injector device mounted on an exhaust gas line at the inlet side of an exhaust gas aftertreatment system according to another embodiment of the present invention and a water injection device placed within a catalyst chamber.

[0060] FIG. 8 is a drawing illustrating a urea injector mechanism mounted in a catalyst chamber of an exhaust gas aftertreatment system according to one embodiment of the present invention and a water injection mechanism disposed within the catalyst chamber.

[0061] FIG. 9 is a drawing showing a urea injector mechanism mounted in a catalyst chamber of an exhaust gas aftertreatment system according to another embodiment of the present invention and a water injection mechanism arranged within the catalyst chamber.

[0062] FIG. 10 is a drawing illustrating a urea injector device mounted on an exhaust gas line at the inlet side of an exhaust gas aftertreatment system according to one embodiment of the present invention and a water injection device positioned within a catalyst chamber.

[0063] FIG. 11 is a drawing showing a urea injector device mounted on an exhaust gas line at the inlet side of an exhaust gas aftertreatment system according to another embodiment of the present invention and a water injection device placed within a catalyst chamber.

[0064] FIG. 12 is a drawing illustrating a regeneration gas supply device connected to an exhaust gas aftertreatment system according to an embodiment of the present invention.

[0065] FIG. 13 is a drawing schematically illustrating the overall structure of an exhaust gas aftertreatment system according to another embodiment of the present invention.

[0066] Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. When designating components in each drawing, it should be noted that, where possible, identical components will be given the same reference numerals, even if they appear in different drawings. Furthermore, when describing embodiments of the present invention, detailed descriptions of related known structures or functions will be omitted if they are deemed to hinder understanding of the embodiments of the present invention.

[0067] In describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and the nature, order, or sequence of the components are not limited by the terms.

[0068] In embodiments of the present invention, the singular may also include the plural unless specifically stated otherwise in the phrase, and when it is described as “at least one (or more) of A and B, C”, it may include one or more of all combinations that can be combined with A, B, C.

[0069] And, when a component is described as being 'connected', 'coupled' or 'connected' to another component, it may include not only cases where the component is directly connected, coupled or connected to the other component, but also cases where the component is 'connected', 'coupled' or 'connected' by another component between the component and the other component.

[0070] Additionally, when described as being formed or arranged "above or below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below", it may include the meaning of a downward direction as well as an upward direction based on one component.

[0071] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0072]

[0073] Referring to FIG. 1, an exhaust gas aftertreatment system according to an embodiment of the present invention may include a multi-fuel engine (1) and a catalyst chamber (11) disposed downstream of the multi-fuel engine (1).

[0074] A multi-fuel engine (1) can be configured to selectively use two or more different types of fuel, such as gaseous fuel (natural gas, methane, etc.), liquid fuel (diesel fuel), etc. For example, the multi-fuel engine (1) can operate in at least one of a gaseous fuel operation mode in which combustion occurs using only gaseous fuel, a liquid fuel operation mode in which combustion occurs using only liquid fuel, and a mixed fuel operation mode in which combustion occurs using a mixed fuel in which gaseous fuel and liquid fuel are mixed.

[0075] The catalyst chamber (11) may include a plurality of catalysts arranged therein, and the plurality of catalysts may be configured to remove various harmful substances contained in exhaust gas discharged from the multi-fuel engine (1). The catalyst chamber (11) may have an inlet (11a) through which exhaust gas flows in and an outlet (11b) through which exhaust gas is discharged, and the plurality of catalysts may be arranged to be spaced apart from each other along the flow direction of the exhaust gas in the internal space of the catalyst chamber (11).

[0076] Fig. 1 illustrates a low-pressure exhaust gas aftertreatment system in which a catalyst chamber (11) is located downstream of a turbocharger (4). That is, the exhaust gas aftertreatment system illustrated in Fig. 1 may be a low-pressure exhaust gas aftertreatment system in which low-pressure exhaust gas discharged from a turbocharger (4) flows into a catalyst chamber (11).

[0077] Referring to FIG. 1, an inlet exhaust gas line (2) can be connected from a multi-fuel engine (1) to an inlet (11a) of a catalyst chamber (11), and an outlet exhaust gas line (3) can be connected to an outlet (11b) of the catalyst chamber (11). Exhaust gas discharged from the multi-fuel engine (1) and the turbocharger (4) flows into the inlet (11a) of the catalyst chamber (11) through the inlet exhaust gas line (2), harmful substances contained in the exhaust gas passing through the catalyst chamber (11) are removed by a plurality of catalysts, and the exhaust gas from which the harmful substances have been removed can be discharged to the outside through the outlet exhaust gas line (3) from the outlet (11b) of the catalyst chamber (11).

[0078] A turbocharger (4) may be arranged in the inlet exhaust gas line (2), and the turbocharger (4) may include a turbine (4a) that rotates by exhaust gas and a compressor (4b) that compresses intake air. The turbine (4a) of the turbocharger (4) may be arranged in the inlet exhaust gas line (2). Accordingly, exhaust gas discharged from the multi-fuel engine (1) may pass through the turbine (4a) of the turbocharger (4) and then flow into the inlet (11a) of the catalyst chamber (11).

[0079] The low-pressure exhaust gas aftertreatment system according to the embodiment of FIG. 1 may further include a bypass line (12) branched from a branch point (2a) of an inlet exhaust gas line (2) and joined to a junction point (3a) of an outlet exhaust gas line (3) so that exhaust gas discharged from a multi-fuel engine (1) bypasses a catalyst chamber (11). The branch point (2a) of the inlet exhaust gas line (2) may be located downstream of a turbine (4a) of a turbocharger (4), and thus, the inlet of the bypass line (12) may be connected to the inlet exhaust gas line (2) at a point downstream of the turbine (4a) of the turbocharger (4).

[0080] Referring to Fig. 1, an inlet valve (13) may be arranged in the inlet exhaust gas line (2), and an outlet valve (14) may be arranged in the outlet exhaust gas line (3). By selectively opening and closing the inlet valve (13) and / or the outlet valve (14), the exhaust gas may or may not pass through the catalyst chamber (11).

[0081] Referring to Fig. 1, a bypass valve (15) can be placed in a bypass line (12), and the exhaust gas can pass through or not pass through the bypass valve (15) by selectively opening and closing the bypass valve (15).

[0082] For initial performance verification, a methane meter can be optionally installed, and after the performance verification is completed, the methane meters (16, 17) can be detached. For example, as illustrated in FIG. 1, an inlet-side methane meter (16) can be detachably installed in an inlet-side exhaust gas line (2), and the inlet-side methane meter (16) can measure the methane concentration in the exhaust gas flowing into the inlet (11a) of the catalyst chamber (11). An outlet-side methane meter (17) can be detachably installed in an outlet-side exhaust gas line (3), and the outlet-side methane meter (17) can measure the methane concentration in the exhaust gas discharged from the outlet (11b) of the catalyst chamber (11).

[0083] Referring to FIG. 1, an inlet temperature sensor (T1) may be disposed adjacent to an inlet (11a) of a catalyst chamber (11), and the inlet temperature sensor (T1) may be configured to measure the upstream temperature of catalysts of the catalyst chamber (11). An outlet temperature sensor (T2) may be disposed adjacent to an outlet (11b) of the catalyst chamber (11), and the outlet temperature sensor (T2) may be configured to measure the downstream temperature of catalysts of the catalyst chamber (11). An intermediate temperature sensor (T3) may be disposed in the middle of the catalyst chamber (11), and may be configured to measure the temperature of a space between chambers disposed within the catalyst chamber (11). A differential pressure transducer (PDT) may be mounted on the catalyst chamber (11), and the differential pressure transducer (PDT) may be configured to measure a pressure difference between an inlet pressure and an outlet pressure of the catalyst chamber (11).

[0084] The controller (20) can control the operation of the inlet valve (13), the outlet valve (14), the bypass valve (15), etc. based on the methane concentration in the exhaust gas measured by the inlet methane meter (16), the methane concentration of the exhaust gas measured by the outlet methane meter (17), the temperature measured by the inlet temperature sensor (T1), the temperature measured by the outlet temperature sensor (T2), the temperature measured by the intermediate temperature sensor (T3), the pressure measured by the differential pressure transducer (PDT), etc.

[0085]

[0086] FIG. 2 is a drawing illustrating one type of catalyst arrangement structure arranged in the internal space of a catalyst chamber (11) of an exhaust gas aftertreatment system according to an embodiment of the present invention. Referring to FIG. 2, the catalyst chamber (11) may include an upstream catalyst (21) arranged adjacent to an inlet of the catalyst chamber (11) and a downstream catalyst (31) arranged adjacent to an outlet of the catalyst chamber (11). The upstream catalyst (21) and the downstream catalyst (31) may be oxidation catalysts. The upstream catalyst (21) may be at least one catalyst among a diesel oxidation catalyst and a methane oxidation catalyst, or a combination thereof, and the downstream catalyst (31) may be at least one catalyst among a methane oxidation catalyst and a diesel oxidation catalyst, or a combination thereof.

[0087] According to the embodiment of FIG. 2, the upstream catalyst (21) may be a diesel oxidation catalyst (DOC) configured to adsorb sulfur components in exhaust gas and reduce sulfur components in exhaust gas discharged from the upstream catalyst (21).

[0088] According to the embodiment of FIG. 2, the downstream catalyst (31) may be a methane oxidation catalyst configured to remove methane generated from uncombusted gaseous fuel.

[0089] According to one embodiment, the catalyst composition content of the upstream catalyst (21) may be relatively less than that of the downstream catalyst (31), and the upstream catalyst (21) may be configured to have a relatively smaller size than the downstream catalyst (31). Accordingly, when the performance of the upstream catalyst (21), which comes into contact with the exhaust gas first, deteriorates due to preemptively reducing or removing hydrocarbons and sulfur, etc., the work of replacing only the upstream catalyst (21) may become easier, and the replacement cost of the upstream catalyst (21) may become relatively cheaper. The replacement cycle of the upstream catalyst (21) may be appropriately determined through various methods capable of directly or indirectly confirming the performance of the upstream catalyst (21), such as a counting method of the operating time, methane oxidation reduction performance, temperature increase, etc.

[0090] According to another embodiment, the content of the catalyst composition of the upstream catalyst (21) may be relatively greater than the content of the catalyst composition of the downstream catalyst (31), and thus an exothermic reaction may be induced in the upstream catalyst (21) during the process in which the exhaust gas reacts with the upstream catalyst (21). Through this, the temperature of the exhaust gas passing through the upstream catalyst (21) may relatively increase due to the exothermic reaction of the upstream catalyst (21), and thus the temperature of the downstream catalyst (31) may increase to the reaction temperature due to the exhaust gas discharged from the upstream catalyst (21), and thus the downstream catalyst (31) may more effectively remove methane contained in the exhaust gas.

[0091] According to another embodiment, the precious metal content of the upstream catalyst (21) may be relatively higher than that of the downstream catalyst (31), so that the upstream catalyst (21) is free from or minimizes degradation in performance due to hydrocarbon poisoning, sulfur poisoning, etc., and can induce an exothermic reaction in the upstream catalyst (21) during the process in which the exhaust gas reacts with the upstream catalyst (21). Through this, the temperature of the exhaust gas passing through the upstream catalyst (21) can relatively increase due to the exothermic reaction of the upstream catalyst (21), and thus the temperature of the downstream catalyst (31) increases to a reaction temperature required by the exhaust gas discharged from the upstream catalyst (21), so that the downstream catalyst (31) can more effectively remove methane contained in the exhaust gas.

[0092]

[0093] FIG. 3 is a drawing illustrating another type of catalyst arrangement structure arranged in the internal space of the catalyst chamber (11) of the exhaust gas aftertreatment system according to an embodiment of the present invention. Referring to FIG. 3, the catalyst chamber (11) may include an upstream catalyst (21) arranged adjacent to the inlet of the catalyst chamber (11) and a plurality of downstream catalysts (31, 32) located downstream of the upstream catalyst (21). The plurality of downstream catalysts (31, 32) may include a first downstream catalyst (31) located downstream of the upstream catalyst (21) and a second downstream catalyst (32) located downstream of the first downstream catalyst (31). The second downstream catalyst (32) may be arranged adjacent to the outlet (11b) of the catalyst chamber (11). The upstream catalyst (21) and the downstream catalysts (31, 32) may be oxidation catalysts. The upstream catalyst (21) may be at least one catalyst among a diesel oxidation catalyst and a methane oxidation catalyst, or a combination thereof, and the downstream catalyst (31, 32) may be at least one catalyst among a methane oxidation catalyst and a diesel oxidation catalyst, or a combination thereof.

[0094] According to the embodiment of FIG. 3, the upstream catalyst (21) may be a diesel oxidation catalyst (DOC) configured to adsorb sulfur components in exhaust gas and reduce sulfur components in exhaust gas discharged from the upstream catalyst (21).

[0095] According to the embodiment of FIG. 3, the first downstream catalyst (31) and the second downstream catalyst (32) may be methane oxidation catalysts configured to remove methane generated from uncombusted gaseous fuel.

[0096] According to one embodiment, the content of the catalyst composition of the first downstream catalyst (31) may be the same as the amount of the catalyst composition of the second downstream catalyst (32), the content of the catalyst composition of the upstream catalyst (21) may be relatively less than the content of the catalyst composition of each downstream catalyst (31, 32), and the upstream catalyst (21) may be configured to have a relatively smaller size than each downstream catalyst (31, 32). Accordingly, when the performance of the upstream catalyst (21) deteriorates as it removes hydrocarbons, sulfur, etc., the work of replacing only the upstream catalyst (21) may become easier, and the replacement cost of the upstream catalyst (21) may become relatively inexpensive.

[0097] According to another embodiment, the content of the catalyst composition of the upstream catalyst (21) may be relatively greater than the content of the catalyst composition of each downstream catalyst (31, 32), and thus an exothermic reaction may be induced in the upstream catalyst (21) during the process in which the exhaust gas reacts with the upstream catalyst (21). Through this, the temperature of the exhaust gas passing through the upstream catalyst (21) may relatively increase due to the exothermic reaction of the upstream catalyst (21), and thus the temperature of the downstream catalyst (31) may increase to a reaction temperature required by the exhaust gas discharged from the upstream catalyst (21), and thus each downstream catalyst (31, 32) may more effectively remove methane contained in the exhaust gas.

[0098] According to another embodiment, the precious metal content of the upstream catalyst (21) may be relatively higher than the precious metal content of each downstream catalyst (31, 32), so that the performance of the upstream catalyst (21) is not degraded or minimized due to hydrocarbon poisoning, sulfur poisoning, etc., and an exothermic reaction can be induced in the upstream catalyst (21) during the process in which the exhaust gas reacts with the upstream catalyst (21). Through this, the temperature of the exhaust gas passing through the upstream catalyst (21) can relatively increase due to the exothermic reaction of the upstream catalyst (21), and thus the temperature of the downstream catalyst (31) increases to a reaction temperature required by the exhaust gas discharged from the upstream catalyst (21), so that each downstream catalyst (31, 32) can more effectively remove methane contained in the exhaust gas.

[0099] The inlet temperature sensor (T1) can measure the upstream temperature of the upstream catalyst (21), the outlet temperature sensor (T2) can measure the downstream temperature of the downstream catalyst (31, 32), and the intermediate temperature sensor (T3) can measure the temperature of the space between the upstream catalyst (21) and the downstream catalyst (31, 32). As the intermediate temperature sensor (T3) actually measures the temperature of the space between the upstream catalyst (21) and the downstream catalyst (31, 32), the increased temperature of the exhaust gas by the upstream catalyst (21) can be practically detected.

[0100] As described above, since the upstream catalyst (21) is located upstream of the downstream catalyst (22), the upstream catalyst (21) can come into contact with and react with the exhaust gas before the downstream catalyst (22), and thus, the exhaust gas, in which hydrocarbons (HC) and sulfur, etc., have been reduced or removed in advance by the upstream catalyst (21), comes into contact with and reacts with the downstream catalyst (31, 32), so that methane contained in the exhaust gas can be efficiently removed or reduced by the downstream catalyst (31, 32), which is a methane oxidation catalyst, and the service life of the downstream catalyst (31, 32), which is a methane oxidation catalyst, can be extended.

[0101] In addition, as the exhaust gas first reacts with the upstream catalyst (21), an exothermic reaction may occur in the upstream catalyst (21), and thus the temperature of the exhaust gas passing through the upstream catalyst (21) may relatively increase due to the exothermic reaction of the upstream catalyst (21), and thus the temperature of the downstream catalyst (31) may increase to the reaction temperature required by the exhaust gas discharged from the upstream catalyst (21), and thus the downstream catalyst (31, 32) may more effectively remove methane contained in the exhaust gas.

[0102]

[0103] The exhaust gas aftertreatment system (10) for a ship according to an embodiment of the present invention may further include an injector mechanism configured to inject an oxidizable substance from the upstream side of the upstream catalyst (21) to the upstream catalyst (21). According to an embodiment, the oxidizable substance may be at least one or a combination of two or more of diesel fuel, LNG, methanol, ethanol, and urea. As the oxidizable substance reacts with the upstream catalyst (21) and is oxidized, the temperature of the exhaust gas passing through the upstream catalyst (21) can relatively increase due to the oxidation reaction of the oxidizable substance, and the downstream catalyst (31, 32) can increase to a required reaction temperature due to the exhaust gas discharged from the upstream catalyst (21). That is, the temperature of the downstream catalyst (31, 32) can be induced to rise by the exhaust gas heated by the upstream catalyst (21), and thus the methane reduction efficiency by the downstream catalyst (31, 32) can be significantly improved. The injector mechanism can be arranged upstream of the upstream catalyst (21). For example, the injector mechanism can be arranged in a part of the catalyst chamber (11) adjacent to the inlet (11a) of the catalyst chamber (11) or in a part of the inlet exhaust gas line (2) adjacent to the catalyst chamber (11). The controller (20) can be configured to control the injector mechanism, the upstream valve (13), the downstream valve (14), and the bypass valve (15) based on the temperature of the downstream catalyst (31, 32) and whether gas stripping occurs in a multi-fuel engine.

[0104] According to the embodiments of FIGS. 4 to 7, the injector mechanism may be a diesel injector mechanism (40) that injects diesel fuel into the upstream catalyst (21).

[0105] Referring to FIGS. 4 to 7, a diesel injector device (40) may include a diesel injector (41) that injects diesel fuel into an upstream catalyst (21), a diesel fuel tank (43) fluidly connected to the diesel injector (41) through a diesel fuel line (42), a fuel pump unit (44) configured to supply diesel fuel to the diesel injector (41), and a fuel dosing unit (45) configured to control the flow rate of the diesel fuel. The fuel pump unit (44) may be configured with a fuel pump and peripheral devices thereof, and the fuel dosing unit (45) may be configured with a fuel flow meter, a fuel flow control valve, and peripheral devices thereof.

[0106] Referring to FIGS. 4 and 5, a diesel injector (41) can be mounted in the catalyst chamber (11) adjacent to the inlet (11a) of the catalyst chamber (11).

[0107] Referring to FIGS. 6 and 7, a diesel injector (41) can be mounted on the inlet exhaust gas line (2).

[0108] As diesel fuel is injected into the upstream catalyst (21) by the diesel injector (41), the diesel fuel is oxidized, and the temperature of the exhaust gas passing through the upstream catalyst (21) may relatively increase due to the oxidation reaction of the diesel fuel, and thus the temperature of the downstream catalyst (31) may increase to the reaction temperature due to the exhaust gas discharged from the upstream catalyst (21). According to one example, the controller (20) may control the fuel pump unit (44) to determine the injection amount of diesel fuel by the diesel injector (41) based on the target temperature (e.g., 300 to 500°C) of the downstream catalyst (31, 32) that can optimize the removal efficiency of methane.

[0109] According to another example, the controller (20) can determine whether the temperature of the downstream catalyst (31, 32) exceeds an allowable temperature based on the upstream temperature of the upstream catalyst (21) measured by the inlet temperature sensor (T1), the downstream temperature of the downstream catalyst (31, 32) measured by the outlet temperature sensor (T2), and the temperature of the space between the upstream catalyst (21) and the downstream catalyst (31, 32) measured by the intermediate temperature sensor (T3). The controller (20) can control the fuel pump unit (44) to reduce the injection amount of diesel fuel when the temperature of the downstream catalyst (31, 32) exceeds the allowable temperature, adjust the opening amount of the bypass valve (15) to allow some of the exhaust gas to pass through the bypass line (12), and close the upstream valve (13) and the downstream valve (14) to block the exhaust gas from passing through the catalyst chamber (11). According to another example, when a gas trip occurs in the multi-fuel engine (1), the controller (20) can stop the fuel pump unit (44) to stop the injection of diesel fuel, close the upstream valve (13) and the downstream valve (14) to block the exhaust gas from passing through the catalyst chamber (11), and fully open the bypass valve (15) to allow the exhaust gas to pass through the bypass line (12). When the gas fuel operation mode of a multi-fuel engine (1) is incomplete, a misfire in the combustion chamber may occur above a certain level, and the multi-fuel engine (1) is converted to a liquid fuel operation mode. This situation is called a gas strip. When such a gas strip occurs, the controller (20) stops the fuel pump unit (44), thereby stopping the injection of diesel fuel, and the controller (20) completely opens the bypass valve (15) and closes the upstream valve (13) and the downstream valve (14), thereby allowing the exhaust gas to pass only through the bypass line (12) and not through the catalyst chamber (11).

[0110] According to the embodiments of FIGS. 8 to 11, the injector mechanism may be a urea injector mechanism (50) configured to inject urea from upstream of the upstream catalyst (21) to the upstream catalyst (21).

[0111] Referring to FIGS. 8 to 11, the urea injector device (50) may include a urea injector (51) that injects urea into an upstream catalyst (21), and a urea dosing unit (53) fluidly connected to the urea injector (51) through a urea line (52). Since the urea dosing unit (53) is connected to the urea supply system of the SCR catalyst device, the urea dosing unit (53) can utilize the urea supply system of the SCR catalyst device.

[0112] Referring to FIGS. 8 and 9, the urea injector (51) can be mounted in the catalyst chamber (11) adjacent to the inlet (11a) of the catalyst chamber (11).

[0113] Referring to FIGS. 10 and 11, the urea injector (51) can be mounted in a portion adjacent to the catalyst chamber (11) of the inlet exhaust gas line (2).

[0114] As urea is injected into the upstream catalyst (21) by the urea injector (51), the urea is oxidized, and the temperature of the exhaust gas passing through the upstream catalyst (21) can relatively rise due to the oxidation reaction of urea, and as the temperature of the downstream catalyst (31) rises to the reaction temperature by the exhaust gas discharged from the upstream catalyst (21), the temperature of the downstream catalyst (31, 32) can be induced to rise.

[0115] According to an example, the controller (20) can control the urea dosing unit (53) to determine the injection amount of urea by the urea injector (51) based on the target temperature (e.g., 300 to 500°C) of the downstream catalyst (31, 32) that can optimize the removal efficiency of methane.

[0116] According to another example, the controller (20) can determine whether the temperature of the downstream catalyst (31, 32) exceeds an allowable temperature based on the upstream temperature of the upstream catalyst (21) measured by the inlet temperature sensor (T1), the downstream temperature of the downstream catalyst (31, 32) measured by the outlet temperature sensor (T2), and the temperature of the space between the upstream catalyst (21) and the downstream catalyst (31, 32) measured by the intermediate temperature sensor (T3). The controller (20) can control the urea dosing unit (53) to reduce the amount of urea injected when the temperature of the downstream catalyst (31, 32) exceeds the allowable temperature, adjust the opening amount of the bypass valve (15) to allow some of the exhaust gas to pass through the bypass line (12), and close the upstream valve (13) and the downstream valve (14) to block the exhaust gas from passing through the catalyst chamber (11).

[0117] According to another example, when a gas trip occurs in a multi-fuel engine (1), the controller (20) can stop the urea dosing unit (53) to stop the injection of urea, close the upstream valve (13) and the downstream valve (14) to block the exhaust gas from passing through the catalyst chamber (11), and fully open the bypass valve (15) to allow the exhaust gas to pass through the bypass line (12). When the gas fuel operation mode of the multi-fuel engine (1) is incomplete, a misfire in the combustion chamber may occur above a certain level, and the multi-fuel engine (1) is converted to the liquid fuel operation mode, and this situation is called a gas trip. When such a gas strip occurs, the controller (20) stops the urea dosing unit (53), thereby stopping the fuel injection of urea, and the controller (20) completely opens the bypass valve (15) and closes the upstream valve (13) and downstream valve (14), thereby allowing the exhaust gas to pass only through the bypass line (12) and not through the catalyst chamber (11).

[0118] According to the embodiments of FIGS. 4 to 11, the upstream catalyst (21), which is a diesel oxidation catalyst, may have a relatively lower precious metal content than the downstream catalyst (31, 32), which is a methane oxidation catalyst, and thus the upstream catalyst (21) may be relatively cheaper than the downstream catalyst (31, 32). Accordingly, the upstream catalyst (21), which is a diesel oxidation catalyst, may primarily reduce or remove catalyst-toxic components such as hydrocarbons (HC) and sulfur (S), thereby extending the service life of the downstream catalyst (31, 32), which is a methane oxidation catalyst.

[0119]

[0120] An exhaust gas aftertreatment system according to an embodiment of the present invention may include a water injector mechanism (60) configured to regenerate the upstream catalyst (21) and the downstream catalyst (31, 32) by injecting water onto the upstream catalyst (21) and the downstream catalyst (31, 32), and the water injector mechanism (60) directly injects water onto the upstream catalyst (21) and the downstream catalyst (31, 32), so that adsorbates adsorbed onto the upstream catalyst (21) and the downstream catalyst (31, 32) can be washed away, thereby allowing the upstream catalyst (21) and the downstream catalyst (31, 32) to be smoothly regenerated.

[0121] Referring to FIGS. 4 to 11, a water injector mechanism (60) may be arranged downstream of the upstream catalyst (21) and downstream of each downstream catalyst (31, 32) in the internal space of the catalyst chamber (11), and the water injector mechanism (60) may include a water pipe (61) extending downstream of the upstream catalyst (21) and downstream of each downstream catalyst (31, 32), and a plurality of water injectors (62) arranged from the water pipe (61) toward the upstream catalyst (21) and each downstream catalyst (31, 32). A water supply source may be connected to the water pipe (61) through a water supply line, and a water pump may be arranged in the water supply line to supply water to the water pipe (61). By each water injector (62) directly injecting water onto the upstream catalyst (21) and the downstream catalyst (31, 32), the adsorbates adsorbed onto the upstream catalyst (21) and the downstream catalyst (31, 32) can be removed, thereby increasing the regeneration efficiency of the upstream catalyst (21) and the downstream catalyst (31, 32).

[0122]

[0123] Referring to FIG. 1, the exhaust gas aftertreatment system according to an embodiment of the present invention may further include a regeneration gas supply device (70) configured to supply regeneration gas to the inlet (11a) of the catalyst chamber (11).

[0124] According to an embodiment, the regeneration gas may include a reducing agent for reducing the catalyst (21, 31, 32) and an inert gas for creating a reducing atmosphere in the internal space of the catalyst chamber (11). According to a specific embodiment, the reducing agent may be CH4, H2, etc., and the inert gas may be N2 as a balance gas for creating a reducing atmosphere.

[0125] Referring to FIG. 12, the regeneration gas supply device (70) may include a reducing agent supply unit (71) that supplies a reducing agent and an inert gas supply unit (74) that supplies an inert gas.

[0126] The reducing agent supply unit (71) may be configured to supply a reducing agent that reduces an oxide substance poisoned on the surface of the catalyst (21, 31, 32) to the internal space of the catalyst chamber (11). According to a specific embodiment, the reducing agent supply unit (71) may be fluidly connected to the inlet exhaust gas line (2) through the reducing agent supply line (72), the reducing agent supply source (73) may be located upstream of the reducing agent supply unit (71), and the reducing agent supply unit (71) may be configured to supply the reducing agent from the reducing agent supply source (73) to the inlet exhaust gas line (2).

[0127] The inert gas supply unit (74) may be configured to supply inert gas into the interior space of the catalyst chamber (11) to create an oxygen-free reducing atmosphere inside the catalyst chamber (11). According to a specific embodiment, the inert gas supply unit (74) may be fluidly connected to the inlet exhaust gas line (2) through the inert gas supply line (75), the inert gas supply source (77) may be located upstream of the inert gas supply unit (74), and the inert gas supply unit (74) may be configured to supply inert gas from the inert gas supply source (77) to the inlet exhaust gas line (2).

[0128] According to an embodiment, the inert gas supply unit (74) may further include a heater (76) configured to heat the inert gas to a set temperature. The heater (76) may be located downstream of the inert gas supply unit (74), and the high-temperature inert gas heated by the heater (76) may be supplied to the internal space of the catalyst chamber (11) through the inlet-side exhaust gas line (2).

[0129] The reducing agent supply line (72) and the inert gas supply line (75) can be joined to the inlet of the regeneration gas supply line (78), and the outlet of the regeneration gas supply line (78) can be fluidly connected to a portion adjacent to the catalyst chamber (11) of the inlet-side exhaust gas line (2). The reducing agent supplied by the reducing agent supply line (72) and the inert gas supplied by the inert gas supply line (75) can be supplied to the inlet-side exhaust gas line (2) through the regeneration gas supply line (78). A reducing agent and an inert gas can be supplied to the inlet (11a) of the catalyst chamber (11) through the exhaust gas line (2) on the inlet side, and thus a reducing atmosphere is created in the internal space of the catalyst chamber (11) by the reducing agent and the high-temperature inert gas, and the oxide substances poisoned on the surface of each catalyst (21, 31, 32) are reduced by the reducing agent, so that each catalyst (21, 31, 32) can be efficiently regenerated by the reducing agent and the inert gas.

[0130]

[0131] The catalyst arrangement structure, diesel injector mechanism, urea injector mechanism, water injector mechanism, regeneration gas supply device, etc. of the catalyst chamber (11) according to the embodiments of FIGS. 2 to 11 are not limited to the low-pressure exhaust gas aftertreatment system of FIG. 1 and can be equally applied to the high-pressure exhaust gas aftertreatment system of FIG. 13.

[0132] Fig. 13 illustrates a high-pressure exhaust gas aftertreatment system in which a catalyst chamber (11) is located upstream of a turbocharger (4). That is, the exhaust gas aftertreatment system illustrated in Fig. 13 may be a high-pressure exhaust gas aftertreatment system in which high-pressure exhaust gas discharged from a multi-fuel engine (1) passes through a catalyst chamber (11) or a bypass line (12) and then flows into the inlet of a turbine (4a) of a turbocharger (4).

[0133] Referring to FIG. 13, an exhaust gas reservoir (1a) can be arranged downstream of a multi-fuel engine (1), and the exhaust gas reservoir (1a) can receive exhaust gas discharged from the multi-fuel engine (1).

[0134] Referring to Fig. 13, an inlet-side exhaust gas line (2) can be connected from an exhaust gas reservoir (1a) to an inlet (11a) of a catalyst chamber (11), and an outlet-side exhaust gas line (3) can be connected from an outlet (11b) of the catalyst chamber (11) to an inlet of a turbine (4a) of a turbocharger (4). Exhaust gas discharged from a multi-fuel engine (1) flows into the inlet (11a) of the catalyst chamber (11) through the exhaust gas reservoir (1a) and the inlet-side exhaust gas line (2), and harmful substances contained in the exhaust gas passing through the catalyst chamber (11) are removed by a plurality of catalysts, and the exhaust gas from which the harmful substances have been removed passes through the turbine (4a) of the turbocharger (4) from the outlet (11b) of the catalyst chamber (11) through the outlet-side exhaust gas line (3), and can then be discharged to the outside.

[0135] The high-pressure exhaust gas aftertreatment system according to the embodiment of Fig. 13 may further include a bypass line (12) branched from the inlet exhaust gas line (2) or the exhaust gas reservoir (1a) and joined to the outlet exhaust gas line (3) so that the exhaust gas bypasses the catalyst chamber (11).

[0136] Referring to Fig. 13, an inlet valve (13) may be arranged in the inlet exhaust gas line (2), and an outlet valve (14) may be arranged in the outlet exhaust gas line (3). By selectively opening and closing the inlet valve (13) and / or the outlet valve (14), the exhaust gas may or may not pass through the catalyst chamber (11).

[0137] Referring to Fig. 13, a bypass valve (15) can be placed in the bypass line (12), and the exhaust gas can pass through or not pass through the bypass valve (15) by selectively opening and closing the bypass valve (15).

[0138] A methane meter may be optionally installed for initial performance verification, and may be removed after the performance verification is completed. In one example, only the outlet-side methane meter (17) may be placed in the outlet-side exhaust gas line (3). For example, a probe may be installed on one side of the outlet-side exhaust gas line (3), and the outlet-side methane meter (17) may be detachably mounted on the probe. In addition, the methane meter (17) may be capable of checking the upstream and downstream measurement levels of methane in the exhaust gas passing through the catalyst chamber (11) with a time difference by the operation of the inlet-side valve (13), the outlet-side valve (14), and the bypass valve (15). According to another example, an inlet-side methane meter (16) may be placed in the inlet-side exhaust gas line (2), and the inlet-side methane meter (16) may measure the methane concentration in the exhaust gas flowing into the inlet (11a) of the catalyst chamber (11). An outlet-side methane meter (17) may be placed in the outlet-side exhaust gas line (3), and the outlet-side methane meter (17) may measure the methane concentration in the exhaust gas discharged from the outlet (11b) of the catalyst chamber (11).

[0139] Referring to FIG. 13, an inlet temperature sensor (T1) may be disposed adjacent to the inlet (11a) of the catalyst chamber (11), and the inlet temperature sensor (T1) may be configured to measure the upstream temperature of the catalysts of the catalyst chamber (11). An outlet temperature sensor (T2) may be disposed adjacent to the outlet (11b) of the catalyst chamber (11), and the outlet temperature sensor (T2) may be configured to measure the downstream temperature of the catalysts of the catalyst chamber (11). An intermediate temperature sensor (T3) may be disposed in the middle of the catalyst chamber (11), and may be configured to measure the temperature of the space between chambers disposed within the catalyst chamber (11). A differential pressure transducer (PDT) may be mounted on the catalyst chamber (11), and the differential pressure transducer (PDT) may be configured to measure the pressure difference between the inlet pressure and the outlet pressure of the catalyst chamber (11).

[0140] The controller (20) can control the operation of the inlet valve (13), the outlet valve (14), the bypass valve (15), etc. based on the methane concentration in the exhaust gas measured by the inlet methane meter (16), the methane concentration of the exhaust gas measured by the outlet methane meter (17), the temperature measured by the inlet temperature sensor (T1), the temperature measured by the outlet temperature sensor (T2), the temperature of the space between the upstream catalyst (21) and the downstream catalyst (31, 32) measured by the intermediate temperature sensor (T3), the pressure measured by the differential pressure transducer (PDT), etc.

[0141] Additionally, a vessel according to an embodiment of the present invention may include an exhaust gas aftertreatment system according to the embodiment described above.

[0142]

[0143] The above description is merely an example of the technical idea of ​​the present invention, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential characteristics of the present invention.

[0144] Accordingly, the embodiments disclosed in the present invention are intended to illustrate, rather than limit, the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical concepts within the scope equivalent thereto should be construed as being included within the scope of the present invention.

Claims

1. 2 A multi-fuel engine configured to selectively utilize two or more different types of fuel; and An exhaust gas aftertreatment system comprising: a catalyst chamber disposed downstream of the multi-fuel engine and including an upstream catalyst and a downstream catalyst positioned downstream of the upstream catalyst.

2. In claim 1, An exhaust gas aftertreatment system in which the catalyst composition content of the upstream catalyst is relatively greater than the catalyst composition content of the downstream catalyst.

3. In claim 1, An exhaust gas aftertreatment system in which the precious metal content of the upstream catalyst is relatively higher than the precious metal content of the downstream catalyst.

4. In claim 1, An exhaust gas aftertreatment system further comprising an inlet-side exhaust gas line connected from the multi-fuel engine to the inlet of the catalyst chamber, and an outlet-side exhaust gas line connected to the outlet of the catalyst chamber. 5.2 A multi-fuel engine configured to selectively utilize different types of fuel; A catalyst chamber disposed downstream of the multi-fuel engine and including an upstream catalyst and a downstream catalyst located downstream of the upstream catalyst; An injector mechanism configured to inject an oxidizable substance into the upstream catalyst from upstream of the upstream catalyst; and An exhaust gas aftertreatment system including a controller for controlling the above injector mechanism.

6. In claim 5, The above injector mechanism is an exhaust gas aftertreatment system which is a diesel injector mechanism configured to inject diesel fuel into the upstream catalyst.

7. In claim 6, The above diesel injector device is an exhaust gas aftertreatment system including a diesel injector that injects diesel fuel into the upstream catalyst, and a fuel pump unit configured to supply diesel fuel to the diesel injector.

8. In claim 5, The above injector mechanism is an exhaust gas aftertreatment system which is a urea injector mechanism configured to inject urea into the upstream catalyst.

9. In claim 8, The above urea injector device is an exhaust gas aftertreatment system including a urea injector that injects urea into the upstream catalyst, and a urea dosing unit that is fluidly connected to the urea injector through a urea line. 10.2 A multi-fuel engine configured to selectively utilize different types of fuel; A catalyst chamber disposed downstream of the multi-fuel engine and including an upstream catalyst and a downstream catalyst located downstream of the upstream catalyst; and An exhaust gas aftertreatment system including a regeneration gas supply device configured to supply regeneration gas to the inlet of the catalyst chamber.

11. In claim 10, The above regeneration gas is an exhaust gas aftertreatment system containing a reducing agent and an inert gas.

12. In claim 10, The above regeneration gas supply device supplies a reducing agent An exhaust gas aftertreatment system including a supply unit and an inert gas supply unit that supplies an inert gas.

13. In claim 12, An exhaust gas aftertreatment system wherein the above inert gas supply unit further includes a heater configured to heat the inert gas.

14. In claim 10, An exhaust gas aftertreatment system further comprising a water injector mechanism configured to inject water into the downstream catalyst.

15. A vessel comprising an exhaust gas aftertreatment system according to any one of claims 1, 5 and 10.

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