Exhaust treatment system

Abstract

The exhaust treatment system (1) includes an exhaust passage (10), a first catalyst device (11), a second catalyst device (21), and a third catalyst device (31). The first catalyst device (11) is disposed upstream of the second catalyst device (21). In addition, the first catalyst device (11) has a first catalyst (12) for decomposing ammonia and a virtual catalyst (13) for not decomposing ammonia. The first catalyst (12) includes a first active metal for decomposing ammonia and a first carrier supporting the first active metal, and the virtual catalyst (13) includes a virtual carrier for not supporting the first active metal.

Description

Technical Field

[0001] This invention relates to an exhaust gas treatment system. More specifically, this invention relates to a system comprising ammonia (NH3), nitrous oxide (N2O), and nitrogen oxides (NOx). X The exhaust gas treatment system. Background Technology

[0002] Previously, the following technology was known: in order to treat exhaust gas, an exhaust gas treatment catalyst was placed in the exhaust gas passage to decompose harmful substances in the exhaust gas.

[0003] For example, as a method for treating nitrogen oxides and nitrous oxide contained in exhaust gas, a technique has been proposed to decompose nitrogen oxides and nitrous oxide by sequentially configuring a denitrification catalyst and a nitrous oxide decomposition catalyst (see, for example, Patent Document 1).

[0004] Patent Document 1 describes an exhaust gas treatment method that involves adding ammonia and / or urea as reducing agents to the exhaust gas, followed by introducing the exhaust gas into a denitrification catalyst and a nitrous oxide decomposition catalyst. Therefore, nitrogen oxides and nitrous oxide in the exhaust gas can be efficiently decomposed.

[0005] [Existing Technical Documents]

[0006] [Patent Literature]

[0007] Patent Document 1: Japanese Patent Application Publication No. 2013-71071 Summary of the Invention

[0008] [The problem the invention aims to solve]

[0009] However, the exhaust treatment method in Patent Document 1 has the following drawbacks: when the exhaust temperature is low, the nitrous oxide decomposition catalyst cannot function fully, and the decomposition efficiency of nitrous oxide becomes low.

[0010] The present invention provides an exhaust gas treatment system that can efficiently decompose nitrous oxide in exhaust gas.

[0011] [Technical means to solve the problem]

[0012] The present invention [1] includes an exhaust gas treatment system for treating exhaust gas containing ammonia, nitrous oxide, and nitrogen oxides. The exhaust gas treatment system includes: an exhaust gas passage for the exhaust gas to flow; a first catalyst device, which is separated from the exhaust gas passage and has a first catalyst for decomposing ammonia and a virtual catalyst for not decomposing ammonia; a second catalyst device, which is separated from the exhaust gas passage and has a second catalyst for decomposing nitrous oxide; and a third catalyst device, which is separated from the exhaust gas passage and has a third catalyst for reducing nitrogen oxides. The first catalyst device is disposed upstream of the second catalyst device. The first catalyst includes a first active metal for decomposing ammonia and a first carrier supporting the first active metal. The virtual catalyst includes a virtual carrier that does not support the first active metal.

[0013] The present invention [2] includes an exhaust treatment system according to [1], wherein the first catalyst and the virtual catalyst are arranged in a direction orthogonal to the flow direction of the exhaust gas, and the first catalyst and the virtual catalyst are respectively configured to be along the flow direction of the exhaust gas.

[0014] The present invention [3] includes an exhaust treatment system according to [1], wherein the first catalyst device includes a mixing unit, wherein the first catalyst and the virtual catalyst are alternately filled in the mixing unit in a direction orthogonal to the flow direction of the exhaust gas, and the mixing unit is provided with a plurality of such mixing units in a direction orthogonal to the flow direction of the exhaust gas.

[0015] The present invention [4] includes an exhaust treatment system according to [1], wherein the first catalyst device includes a first unit filled only with the first catalyst and a virtual unit filled only with the virtual catalyst, and a plurality of the first unit and the virtual unit are arranged in a direction orthogonal to the flow direction of the exhaust.

[0016] The present invention [5] includes an exhaust treatment system according to any one of [1] to [4], wherein the first catalyst and the virtual catalyst are each in the shape of a flat plate and / or a corrugated plate along the flow direction of the exhaust gas.

[0017] The present invention [6] includes an exhaust treatment system according to [5], wherein the first carrier and the virtual carrier are respectively flat glass paper and / or corrugated glass paper along the flow direction of the exhaust.

[0018] The present invention [7] includes an exhaust treatment system according to any one of [1] to [4], wherein the third catalyst device is disposed downstream of the second catalyst device.

[0019] The present invention [8] includes an exhaust treatment system according to any one of [1] to [4], wherein the third catalyst device is disposed upstream of the first catalyst device.

[0020] The present invention [9] includes an exhaust treatment system according to any one of [1] to [4], wherein the third catalyst device is disposed between the first catalyst device and the second catalyst device.

[0021] [The effects of the invention]

[0022] In the exhaust gas treatment system of the present invention, the first catalyst device is disposed upstream of the second catalyst device, so the exhaust gas is introduced into the second catalyst device after passing through the first catalyst device. Therefore, even when the exhaust gas temperature is low, the exhaust gas temperature rises due to the heat generated during the decomposition (oxidation) of ammonia in the first catalyst device, and nitrous oxide can be decomposed efficiently in the second catalyst device.

[0023] Furthermore, in the exhaust gas treatment system of the present invention, the first catalyst device includes a first catalyst and a dummy catalyst. Thus, a portion of the ammonia in the exhaust gas is decomposed, while the remaining ammonia is not decomposed and is introduced into the second catalyst device. Moreover, even if the composition and / or flow rate of the exhaust gas changes, the proportion of the remaining ammonia can be kept constant. Therefore, in the second catalyst device, ammonia can be used as a reducing agent for the decomposition of nitrous oxide, enabling highly efficient decomposition of nitrous oxide.

[0024] Furthermore, in the exhaust gas treatment system of the present invention, the first catalyst device includes a first catalyst and a virtual catalyst. Therefore, without setting a bypass in the exhaust passage, ammonia can be introduced into the second catalyst device 21 in a certain proportion without decomposition, thereby simplifying the device structure and saving space. Attached Figure Description

[0025] [ Figure 1 ] Figure 1 This is a schematic structural diagram showing the exhaust treatment system according to the first embodiment of the present invention.

[0026] [ Figure 2 ] Figure 2 This is a perspective view of a first catalyst device comprising a mixing unit that alternately fills a first catalyst and a virtual catalyst in a direction orthogonal to the direction of exhaust flow.

[0027] [ Figure 3 ] Figure 3 This is a perspective view of a first catalyst apparatus comprising a first unit filled only with a first catalyst and a virtual unit filled only with a virtual catalyst.

[0028] [ Figure 4 ] Figure 4 This is a schematic structural diagram illustrating the exhaust treatment system according to the second embodiment of the present invention.

[0029] [ Figure 5 ] Figure 5 This is a schematic structural diagram illustrating the exhaust treatment system according to the third embodiment of the present invention. Detailed Implementation

[0030] 1. First Implementation Method

[0031] Reference Figure 1 The first embodiment of the exhaust treatment system 1 will be described.

[0032] Exhaust treatment system 1 is, for example, a system for treating exhaust gas discharged from a combustion device.

[0033] Exhaust gas includes ammonia, nitrous oxide, and nitrogen oxides. Examples include exhaust gas from combustion devices that use ammonia fuel or fuels mixed with fossil fuels (such as gasoline and heavy oil), and exhaust gas from chemical plants or power plants. Furthermore, examples of such combustion devices include land-based engines and marine engines.

[0034] The composition of the exhaust gas (the concentrations of oxygen, ammonia, nitrous oxide, and nitrogen oxides contained in the exhaust gas) is not particularly limited. As will be described later, for example, the oxygen and ammonia concentrations in the exhaust gas can vary depending on the combustion conditions of the combustion device. Therefore, sometimes the oxygen concentration in the exhaust gas is insufficient, or sometimes a sufficient amount of ammonia cannot be provided. In such cases, the oxygen and ammonia concentrations in the exhaust gas can be appropriately changed by changing the combustion conditions of the combustion device or by supplying a reducing agent to the exhaust passage 10 using the reducing agent supply device described later.

[0035] There is no particular limitation on the flow rate of exhaust gas.

[0036] There is no particular limitation on the exhaust temperature. The exhaust inlet temperature is, for example, 300°C or higher, preferably 350°C or higher, and for example, 450°C or lower, preferably 400°C or lower.

[0037] In the following explanation, the upstream side and the downstream side refer to the upstream and downstream sides in the direction of exhaust flow.

[0038] The exhaust treatment system 1 of the first embodiment includes: an exhaust passage 10, a first catalyst device 11, a second catalyst device 21, and a third catalyst device 31. Specifically, it includes: an exhaust passage 10; a first catalyst device 11, which is separated from the exhaust passage 10 and has a first catalyst 12 for decomposing ammonia and a virtual catalyst 13 for not decomposing ammonia; a second catalyst device 21, which is separated from the exhaust passage 10 and has a second catalyst for decomposing nitrous oxide; and a third catalyst device 31, which is separated from the exhaust passage 10 and has a third catalyst for reducing nitrogen oxides. In the exhaust treatment system 1 of the first embodiment, the first catalyst device 11, the second catalyst device 21, and the third catalyst device 31 are sequentially included from the upstream side to the downstream side.

[0039] 1.1. Exhaust passage

[0040] The upstream end (inlet) of the exhaust passage 10 is connected to the outlet of the exhaust gas discharged from the combustion device. The exhaust gas discharged from the combustion device flows in the exhaust passage 10. In addition, the downstream end of the exhaust passage 10 is open to the outside air or connected to a known aftertreatment device.

[0041] 1.2. First Catalyst Unit

[0042] The first catalyst device 11 is separated from the exhaust passage 10 and has a first catalyst 12 for decomposing (oxidizing) ammonia and a virtual catalyst 13 for not decomposing ammonia. When exhaust gas passes through the first catalyst device 11, a portion of the ammonia in the exhaust gas is decomposed, while the remaining portion of the ammonia in the exhaust gas remains undecomposed. In addition, the first catalyst device 11 is disposed upstream of the second catalyst device 21.

[0043] <An embodiment of the first catalyst device>

[0044] Reference Figure 2 An embodiment of the first catalyst device 11 will be described.

[0045] like Figure 2 As shown, the first catalyst device 11 includes, for example, a mixing unit 14. The mixing unit 14 includes a housing 41, a first catalyst 12 filled within the housing 41, and a dummy catalyst 13.

[0046] The first catalyst device 11 includes multiple mixing units 14. The number of mixing units 14 in the first catalyst device 11 is not particularly limited, as long as there are two or more, and can be adjusted appropriately according to the installation space of the exhaust treatment system 1. Furthermore, the arrangement of the mixing units 14 is also not particularly limited, as long as multiple units are arranged in a direction orthogonal to the exhaust flow direction. Figure 2In one embodiment of the first catalyst device 11 shown, a plurality of mixing units 14 are arranged along a first direction (e.g., the width direction) orthogonal to the exhaust flow direction and a second direction (e.g., the height direction) orthogonal to the exhaust flow direction and the first direction.

[0047] The shape of the housing 41 is not particularly limited; for example, square and cylindrical shapes extending in the direction of exhaust flow can be listed. Preferably, a square cylindrical shape extending in the direction of exhaust flow is listed. Specifically, the housing 41 can include: a housing body that is generally U-shaped in cross-section and a flat cover covering its opening; a housing body that is only generally U-shaped in cross-section; and a housing body that is generally L-shaped in cross-section and a cover that is generally inverted L-shaped in cross-section fitted therewith.

[0048] The dimensions of the housing 41 can be adjusted appropriately according to the application. Specifically, the length of the housing 41 in the width direction is not particularly limited as long as it can accommodate the first catalyst 12 and / or the dummy catalyst 13. In addition, the length of the housing 41 in the height direction is not particularly limited as long as it can ensure an appropriate number of layers of the first catalyst 12 and / or the dummy catalyst 13.

[0049] Inorganic fiber felt 42 can be laid on the entire inner circumferential surface of the housing 41. Vibration can be suppressed by laying inorganic fiber felt 42 on the inner surface of the housing 41.

[0050] Inorganic fibers used as inorganic fiber felt 42 include, for example, ceramic fibers, glass fibers, silica sol fibers, alumina fibers, and rock wool. Ceramic fibers are preferred.

[0051] In the mixing unit 14, within the housing 41, along a direction orthogonal to the exhaust flow direction (in... Figure 2 The first catalyst 12 and the virtual catalyst 13 are alternately filled in the second direction (height direction). Specifically, in the mixing unit 14, within the housing 41, the first catalyst region 15 and the virtual catalyst region 16 are alternately stacked along the second direction (height direction).

[0052] The number of layers of the first catalyst region 15 and the virtual catalyst region 16 in the mixing unit 14 is not particularly limited; they can be the same or different.

[0053] In the first catalyst region 15, the plate-shaped first catalyst 12 and the corrugated first catalyst 12 are stacked without alternating bonding. In the virtual catalyst region 16, the plate-shaped virtual catalyst 13 and the corrugated virtual catalyst 13 are stacked without alternating bonding. Through such stacking, the first catalyst 12 and the virtual catalyst 13 form a cross-sectional mesh structure (honeycomb structure).

[0054] The number of stacked layers of the plate-shaped first catalyst 12 and the corrugated first catalyst 12 in the first catalyst region 15 is not particularly limited. Specifically, the plate-shaped first catalyst 12 and the corrugated first catalyst 12 can be in one group or multiple groups.

[0055] There is no particular limitation on the number of stacked layers of the plate-shaped virtual catalyst 13 and the corrugated virtual catalyst 13 in the virtual catalyst region 16. Specifically, the plate-shaped virtual catalyst 13 and the corrugated virtual catalyst 13 can be in one group or multiple groups.

[0056] In the mixing unit 14, the proportion of the volume of the first catalyst 12 relative to the total volume of the first catalyst 12 and the virtual catalyst 13 is, for example, 60% or more, preferably 70% or more, and for example, 95% or less, preferably 85% or less.

[0057] In the mixing unit 14, the proportion of the volume of the virtual catalyst 13 relative to the total volume of the first catalyst 12 and the virtual catalyst 13 is, for example, 5% or more, preferably 15% or more, and for example, 40% or less, preferably 30% or less.

[0058] [First Catalyst]

[0059] As described above, the first catalyst 12 is arranged in a direction orthogonal to the exhaust flow direction and configured to be along the exhaust flow direction. Furthermore, the first catalyst 12 is a flat plate and / or a corrugated plate shape along the exhaust flow direction.

[0060] The first catalyst 12 includes a first active metal for decomposing ammonia and a first carrier supporting the first active metal. By contacting exhaust gas with the first catalyst 12, ammonia in the exhaust gas can be decomposed.

[0061] The first active metal is not particularly limited as long as it can decompose (oxidize) ammonia into nitrogen and water. Examples of first active metals include transition metals and depleted metals, with transition metals being preferred. Examples of transition metals include molybdenum, vanadium, tungsten, platinum, palladium, rhodium, ruthenium, iridium, manganese, copper, silver, cobalt, iron, and nickel. Platinum is preferred. Two or more first active metals may be used alone or in combination.

[0062] As a first carrier, inorganic fiber sheets can be cited as an example. Examples of inorganic fiber sheets include cellophane and ceramic paper. Cellophane is preferred.

[0063] Commercially available cellophane containing organic adhesives can also be used. Examples of organic adhesives used in commercially available cellophane include: acrylic resins, polyvinyl alcohol (PVA)-polyvinyl acetate copolymers, unsaturated polyester resins, and epoxy resins.

[0064] The shape of the first carrier is, for example, a flat plate and / or a corrugated plate shape along the exhaust flow direction. That is, the shape of the first carrier determines the shape of the first catalyst 12. The first carrier is preferably a flat plate and / or a corrugated plate shape of cellophane along the exhaust flow direction. More preferably, it is a flat plate shape of cellophane and a corrugated plate shape of cellophane along the exhaust flow direction.

[0065] If the first catalyst 12 is shaped like a flat plate and / or a corrugated plate along the direction of exhaust flow, the first active metal can be efficiently supported on the first carrier, thereby ensuring the contact area with the exhaust. Consequently, ammonia can be efficiently decomposed.

[0066] The dimensions of the first carrier are adjusted appropriately according to the application. Specifically, there are no particular limitations on the length in the exhaust flow direction and the length in the width direction of the first carrier. For example, the length in the exhaust flow direction of the first carrier is 100 mm to 2000 mm. For example, the length in the width direction of the first carrier is 100 mm to 2000 mm.

[0067] The thickness of the first carrier is, for example, 0.1 mm to 1.0 mm.

[0068] The loading of the first active metal per unit volume of the first catalyst is, for example, 0.1 g / L or more, preferably 1 g / L or more, and for example, 10 g / L or less, preferably 5 g / L or less.

[0069] [Method for manufacturing the first catalyst]

[0070] The first catalyst 12 is formed, for example, by coating a slurry containing a first active metal onto a first support and then calcining it. Specifically, a sol (inorganic binder sol) is prepared by dispersing an inorganic binder in a dispersion medium. The first active metal is added to the inorganic binder sol to prepare a slurry containing the first active metal and the inorganic binder. The slurry containing the first active metal and the inorganic binder is coated onto a first support and dried and calcined as needed, thereby obtaining the first catalyst 12 with the first active metal supported on the first support.

[0071] Inorganic binders improve the strength of the first carrier. Examples of inorganic binders include inorganic oxides. Examples of inorganic oxides include zeolites, titanium dioxide, alumina, zirconium oxide, and silicon dioxide. Silicon dioxide is preferred. Inorganic binders can be used alone or in combination of two or more.

[0072] There are no particular limitations on the dispersion medium; examples include water and organic solvents.

[0073] The first catalyst 12 may also include additives other than inorganic binders, if needed.

[0074] Methods for coating a slurry containing a first active metal onto a first carrier include, for example, hot dipping, brush coating, spray coating, and drop coating. Brush coating is a preferred method.

[0075] [Virtual Catalyst]

[0076] As described above, the virtual catalyst 13 is arranged in a direction orthogonal to the exhaust flow direction and configured to be along the exhaust flow direction. Furthermore, the virtual catalyst 13 is a flat plate and / or a corrugated plate shape along the exhaust flow direction.

[0077] The virtual catalyst 13 comprises a virtual carrier that does not support the first active metal for the decomposition of ammonia. That is, even if the exhaust gas comes into contact with the virtual catalyst 13, the ammonia in the exhaust gas will not be decomposed.

[0078] As a virtual carrier, for example, a carrier identical to the first carrier described in the first catalyst 12 can be listed. Cellophane is preferably an example. Commercially available cellophane described in the first catalyst 12 can be used.

[0079] The virtual carrier has a shape, for example, that of a flat plate and / or a corrugated plate along the exhaust flow direction. That is, the shape of the virtual carrier determines the shape of the virtual catalyst. The virtual carrier is preferably a flat plate-shaped cellophane and / or a corrugated cellophane along the exhaust flow direction. More preferably, it is a flat plate-shaped cellophane and a corrugated cellophane along the exhaust flow direction.

[0080] [Methods for manufacturing virtual catalysts]

[0081] Virtual catalyst 13 is formed, for example, by coating a slurry that does not contain a first active metal onto a virtual support and then calcining it. Specifically, a sol (inorganic binder sol) is prepared by dispersing an inorganic binder in a dispersion medium. The inorganic binder sol is coated onto the virtual support and dried and calcined as needed, thereby obtaining virtual catalyst 13.

[0082] Inorganic binders enhance the strength of the virtual carrier. Examples of inorganic binders include those described in the first catalyst 12. Inorganic binders can be used alone or in combination of two or more.

[0083] As a dispersion medium, the same dispersion medium as that described in the first catalyst 12 can be listed.

[0084] Virtual catalyst 13 may also include additives other than inorganic binders, as needed.

[0085] In addition, as a method for coating the slurry on the virtual carrier, the same method as the coating method described in the first catalyst 12 can be listed.

[0086] [Manufacturing method of hybrid unit]

[0087] A first catalyst region 15 is formed by alternately stacking a flat first catalyst 12 along the exhaust flow direction and a corrugated first catalyst 12 along the exhaust flow direction in the height direction, as described above. Similarly, a virtual catalyst region 16 is formed by alternately stacking a flat virtual catalyst 13 along the exhaust flow direction and a corrugated virtual catalyst 13 along the exhaust flow direction in the height direction.

[0088] A mixing unit 14 can be manufactured by alternately arranging a first catalyst region 15 and a virtual catalyst region 16 within a housing 41 in which an inorganic fiber felt 42 is laid on the entire surface of the inner circumferential surface.

[0089] <Other embodiments of the first catalyst device>

[0090] Reference Figure 3 Other embodiments of the first catalyst device 11 will be described. Furthermore, detailed descriptions of structures identical to one embodiment of the first catalyst device 11 will be omitted.

[0091] like Figure 3 As shown, the first catalyst device 11 includes, for example, a first unit 17 and a virtual unit 18. The first unit 17 includes a housing 41 and a first catalyst 12 filled within the housing 41. The virtual unit 18 includes a housing 41 and a virtual catalyst 13 filled within the housing 41.

[0092] The first catalyst device 11 includes multiple first units 17 and multiple virtual units 18. There is no particular limitation on the number of each of the first units 17 and virtual units 18 in the first catalyst device 11, as long as there is one or more, and the number can be adjusted appropriately according to the installation space of the exhaust treatment system 1. Furthermore, there is no particular limitation on the arrangement of the first units 17 and virtual units 18, as long as multiple units are arranged in a direction orthogonal to the exhaust flow direction. Figure 3 In other embodiments of the first catalyst device 11 shown, a plurality of first units 17 and a plurality of virtual units 18 are arranged alternately along the width and height directions.

[0093] When the first catalyst device 11 includes a first unit 17 and a virtual unit 18, the proportion of the volume of the first unit 17 in the first catalyst device 11 relative to the total volume of the first unit 17 and the virtual unit 18 is, for example, 60% or more, preferably 70% or more, and for example, 95% or less, preferably 85% or less.

[0094] When the first catalyst device 11 includes a first unit 17 and a virtual unit 18, the proportion of the volume of the virtual unit 18 in the first catalyst device 11 relative to the total volume of the first unit 17 and the virtual unit 18 is, for example, 5% or more, preferably 15% or more, and for example, 40% or less, preferably 30% or less.

[0095] As the housing 41, for example, the same housing as described in one embodiment of the first catalyst device 11 can be cited.

[0096] In the first unit 17, within the housing 41, the first catalyst 12 is filled in a direction orthogonal to the flow direction of the exhaust gas. Specifically, in the first unit 17, within the housing 41, there is a first catalyst region 15 consisting only of flat first catalyst 12 and corrugated first catalyst 12 stacked without alternating adhesion. Through such stacking, the first catalyst 12 forms a cross-sectional mesh structure (honeycomb structure).

[0097] In the virtual unit 18, within the housing 41, the virtual catalyst 13 is filled in a direction orthogonal to the exhaust flow direction. Specifically, in the virtual unit 18, within the housing 41, there is a virtual catalyst region 16 consisting of flat virtual catalyst 13 and corrugated virtual catalyst 13 stacked without alternating adhesion, only in a direction orthogonal to the exhaust flow direction. Through such stacking, the virtual catalyst 13 forms a cross-sectional mesh structure (honeycomb structure).

[0098] In the first unit 17, a first catalyst region 15 is formed by alternately stacking a flat first catalyst 12 along the exhaust flow direction and a corrugated first catalyst 12 along the exhaust flow direction, as described above, in the height direction. Then, the first catalyst region 15 is disposed only in a housing 41 in which inorganic fiber felt 42 is laid on the entire surface of the inner circumferential surface, thereby manufacturing the first unit 17.

[0099] Similarly, in the virtual unit 18, a virtual catalyst region 16 is formed by alternately stacking flat virtual catalyst 13 along the exhaust flow direction and corrugated virtual catalyst 13 along the exhaust flow direction in the height direction. Then, the virtual catalyst region 16 is disposed only in the housing 41, on which the entire surface of the inner circumferential surface is covered with inorganic fiber felt 42, thereby manufacturing the virtual unit 18.

[0100] 1.3. Second catalyst unit

[0101] The second catalyst device 21 is interposed in the exhaust passage 10 and has a second catalyst for decomposing nitrous oxide. By passing exhaust gas through the second catalyst device 21, nitrous oxide in the exhaust gas can be decomposed. In this embodiment, the second catalyst device 21 is disposed downstream of the first catalyst device 11 and upstream of the third catalyst device 31.

[0102] The second catalyst device 21 includes, for example, a second unit. The second unit includes a housing and a second catalyst filled within the housing.

[0103] The second catalyst device 21 includes multiple second units. There is no particular limitation on the number of second units in the second catalyst device 21, as long as there are two or more, and the number can be adjusted appropriately according to the installation space of the exhaust treatment system 1. Furthermore, there is no particular limitation on the arrangement of the second units, as long as multiple units are arranged in a direction orthogonal to the exhaust flow direction. The second units are preferably arranged along both the width and height directions.

[0104] As the housing 41, for example, the same housing as described in one embodiment of the first catalyst device 11 can be cited.

[0105] In the second unit, within the housing, the second catalyst is filled in a direction orthogonal to the exhaust flow direction. Specifically, in the second unit, within the housing, there is a second catalyst region consisting only of flat-plate and corrugated second catalyst layers stacked without alternating adhesion. Through this stacking, the second catalyst forms a cross-sectional mesh structure (honeycomb structure).

[0106] There is no particular limitation on the number of layers of the plate-shaped and corrugated second catalysts in the second catalyst region.

[0107] [Second Catalyst]

[0108] The second catalyst is arranged in a direction orthogonal to the exhaust flow direction and configured to run along the exhaust flow direction. Furthermore, the second catalyst is a flat plate and / or a corrugated plate shape running along the exhaust flow direction.

[0109] The second catalyst comprises a second active metal that decomposes nitrous oxide. Nitrous oxide in the exhaust gas can be decomposed by contacting the exhaust gas with the second catalyst. Furthermore, the second catalyst preferably also includes a second support carrying the second active metal.

[0110] The second active metal is not particularly limited as long as it can decompose nitrous oxide. Examples of second active metals include transition metals and depleted metals, with transition metals being preferred. Examples of transition metals include cobalt, nickel, and iron, with cobalt and iron being more preferred. Two or more second active metals can be used alone or in combination.

[0111] In addition, the second catalyst may also include a second active metal and a co-catalyst component.

[0112] As a co-catalyst component, examples include alkali metals and alkaline earth metals, with alkali metals being the preferred choice.

[0113] As a second carrier, examples include carriers identical to the first carrier described in the first catalyst 12. Cellophane is a preferred example. Commercially available cellophane described in the first catalyst 12 can be used.

[0114] The shape of the second carrier can be, for example, the same shape as the first carrier described in the first catalyst 12. That is, the second carrier is determined to have the same shape as the second catalyst. The second carrier is preferably a flat glass paper and / or a corrugated glass paper along the exhaust flow direction. More preferably, it is a flat glass paper and a corrugated glass paper along the exhaust flow direction.

[0115] If the second catalyst is shaped like a flat plate and / or a corrugated plate along the direction of exhaust flow, the second active metal can be efficiently supported on the second carrier, thus ensuring a large contact area with the exhaust. Consequently, nitrous oxide can be efficiently decomposed.

[0116] The size of the second support can be adjusted as appropriate for the application. Specifically, the size of the second support may be the same as that of the first support described in the first catalyst 12.

[0117] The loading of the second active metal per unit volume of the second catalyst is, for example, 0.1 g / L or more, preferably 1 g / L or more, and for example, 10 g / L or less, preferably 5 g / L or less.

[0118] [Method for manufacturing the second catalyst]

[0119] The second catalyst is formed, for example, by coating a slurry containing a second active metal onto a second support and then calcining it. Specifically, a sol (inorganic binder sol) is prepared by dispersing an inorganic binder in a dispersion medium. A second active metal and a co-catalyst component are added to the inorganic binder sol to prepare a slurry containing the second active metal, the co-catalyst component, and the inorganic binder. The slurry containing the second active metal, the co-catalyst component, and the inorganic binder is coated onto a second support and dried and calcined as needed, thereby supporting the second active metal on the second support and obtaining the second catalyst.

[0120] Inorganic binders improve the strength of the first carrier. Examples of inorganic binders include those similar to those described in the first catalyst 12.

[0121] The dispersion medium is not particularly limited, and for example, the same dispersion medium as that described in the first catalyst 12 can be listed.

[0122] The second catalyst may also include, as needed, co-catalyst components and additives other than inorganic binders.

[0123] As a method for coating a slurry containing a second active metal onto a second carrier, for example, the same coating method described in the first catalyst can be cited.

[0124] [Manufacturing Method of Unit Two]

[0125] In the second unit, a second catalyst region is formed by alternately stacking a flat second catalyst (manufactured as described above) along the exhaust flow direction and a corrugated second catalyst (manufactured as described above) along the height direction. Then, the second catalyst region is disposed only within a housing in which an inorganic fiber felt is laid across the entire inner circumferential surface, thereby manufacturing the second unit.

[0126] 1.4. Third Catalyst Unit

[0127] The third catalyst device 31 is interposed in the exhaust passage 10 and has a third catalyst for decomposing nitrogen oxides. By passing exhaust gas through the third catalyst device 31, nitrogen oxides in the exhaust gas can be decomposed. In this embodiment, the third catalyst device 31 is disposed downstream of the second catalyst device 21.

[0128] The third catalyst device 31 includes, for example, a third unit. The third unit includes a housing 41 and a third catalyst filled within the housing 41.

[0129] The third catalyst device 31 includes multiple third units. There is no particular limitation on the number of third units in the third catalyst device 31, as long as there are two or more, and the number can be adjusted appropriately according to the installation space of the exhaust treatment system 1. Furthermore, there is no particular limitation on the arrangement of the third units, as long as multiple units are arranged in a direction orthogonal to the exhaust flow direction. Preferably, the third units are arranged along both the width and height directions.

[0130] As the housing 41, for example, the same housing as described in one embodiment of the first catalyst device 11 can be cited.

[0131] In the third unit, within the housing, the third catalyst is filled in a direction orthogonal to the exhaust flow direction. Specifically, in the third unit, within the housing, there is a third catalyst region consisting only of flat-plate and corrugated third catalyst layers stacked without alternating adhesion. Through this filling, the third catalyst forms a cross-sectional mesh structure (honeycomb structure).

[0132] There is no particular limitation on the number of stacked layers of the plate-shaped and corrugated third catalysts in the third catalyst region.

[0133] [Third Catalyst]

[0134] The third catalyst is arranged in a direction orthogonal to the exhaust flow direction and configured to run along the exhaust flow direction. Furthermore, the third catalyst is a flat plate and / or a corrugated plate shape running along the exhaust flow direction.

[0135] The third catalyst includes a third active metal that decomposes nitrogen oxides. By contacting the exhaust gas with the third catalyst, nitrogen oxides in the exhaust gas can be decomposed. Furthermore, the third catalyst preferably also includes a third support carrying the third active metal.

[0136] The third active metal is not particularly limited as long as it can decompose nitrogen oxides. Examples of third active metals include transition metals and depleted metals, with transition metals being preferred. Examples of transition metals include molybdenum, vanadium, tungsten, nickel, cobalt, and iron. Two or more third active metals can be used alone or in combination.

[0137] As a third carrier, examples include carriers identical to the first carrier described in the first catalyst 12. Cellophane is a preferred example. Commercially available cellophane described in the first catalyst 12 can be used.

[0138] The shape of the third carrier can be, for example, the same shape as the first carrier described in the first catalyst 12. That is, the shape of the third carrier determines the shape of the third catalyst. The third carrier is preferably a flat glass paper and / or a corrugated glass paper along the exhaust flow direction. More preferably, it is a flat glass paper and a corrugated glass paper along the exhaust flow direction.

[0139] If the third catalyst is shaped like a flat plate and / or a corrugated plate along the exhaust flow direction, the third active metal can be efficiently supported on the third carrier, thus ensuring a large contact area with the exhaust. This, in turn, allows for efficient decomposition of nitrogen oxides.

[0140] The size of the third support can be adjusted as appropriate for the application. Specifically, the size of the third support may be the same as that of the first support described in the first catalyst 12.

[0141] The loading of the third active metal per unit volume of the third catalyst is, for example, 0.1 g / L or more, preferably 1 g / L or more, and for example, 10 g / L or less, preferably 5 g / L or less.

[0142] [Method for manufacturing the third catalyst]

[0143] The third catalyst is formed, for example, by coating a slurry containing a third active metal onto a third support and then calcining it. Specifically, a sol (inorganic binder sol) is prepared by dispersing an inorganic binder in a dispersion medium. The third active metal is added to the inorganic binder sol to prepare a slurry containing the third active metal and the inorganic binder. The slurry containing the third active metal and the inorganic binder is coated onto a third support and dried and calcined as needed, thereby supporting the third active metal on the third support and obtaining the third catalyst.

[0144] Inorganic binders improve the strength of the third carrier. Examples of inorganic binders include those similar to those described in the first catalyst 12.

[0145] The dispersion medium is not particularly limited, and for example, the same dispersion medium as that described in the first catalyst 12 can be listed.

[0146] The third catalyst may also include additives other than inorganic binders, as needed.

[0147] As a method for coating a slurry containing a third active metal onto a third carrier, a method identical to the coating method described in the first catalyst 12 can be cited as an example.

[0148] [Manufacturing Method of Unit 3]

[0149] In the third unit, a third catalyst region is formed by alternately stacking a flat plate-shaped third catalyst along the exhaust flow direction and a corrugated plate-shaped third catalyst along the exhaust flow direction, as described above, along the height direction. Then, the third catalyst region is disposed only within a housing in which inorganic fiber felt is laid on the entire surface of the inner circumferential surface, thereby manufacturing the third unit.

[0150] 1.5. Other Structures

[0151] Although not shown in the figure, the exhaust treatment system 1 may also include a concentration sensor, a reducing agent supply device, and a control unit.

[0152] [Concentration Sensor]

[0153] As a concentration sensor, examples include non-contact gas concentration meters that detect oxygen or ammonia concentrations in exhaust gas.

[0154] There are no particular limitations on the configuration of the concentration sensor. For example, the concentration sensor may be configured in the exhaust passage 10 upstream of at least one of the first catalyst unit 11, the second catalyst unit 21, and the third catalyst unit. In addition, the concentration sensor is electrically connected to the control unit described later.

[0155] The oxygen concentration in the exhaust gas can be detected by a concentration sensor, and the combustion conditions of the combustion device can be changed by a control unit.

[0156] The ammonia concentration in the exhaust gas can be detected by a concentration sensor, and an appropriate amount of reducing agent can be supplied from the reducing agent supply device described later through a control unit.

[0157] [Reducing agent supply device]

[0158] There are no particular limitations on the configuration of the reducing agent supply device, which is the reducing agent supply unit. The reducing agent supply device is connected, for example, to the exhaust passage 10 downstream of the concentration sensor and upstream of at least one of the first catalyst device 11, the second catalyst device 21, and the third catalyst device. In addition, the reducing agent supply device is electrically connected to the control unit described later.

[0159] Although not shown, the reducing agent supply device can be any structure capable of supplying reducing agent to the exhaust passage 10. For example, it may include a tank for containing the reducing agent, a metering pump for supplying the reducing agent to the exhaust passage 10, and a valve. The reducing agent supply device, for example, adjusts the flow rate of the metering pump and the opening degree of the valve according to the supply amount to supply the reducing agent to the exhaust passage 10.

[0160] Examples of reducing agents supplied from the reducing agent supply device include: ammonia, ammonia water, and urea water.

[0161] [Control Unit]

[0162] The control unit is a unit that performs electrical control in the exhaust treatment system 1. The control unit includes a microcomputer comprising a processing unit (central processing unit (CPU)) and a memory unit. The exhaust treatment system 1 is controlled in the control unit based on a control program stored in the memory unit.

[0163] In addition, as mentioned above, the control unit is electrically connected to the concentration sensor and the reducing agent supply device.

[0164] The control unit adjusts the amount of reducing agent supplied from the reducing agent supply device based on the concentration of ammonia detected by the concentration sensor.

[0165] 1.5. Effects

[0166] In a first embodiment of the exhaust gas treatment system of the present invention, a first catalyst device 11 is disposed upstream of a second catalyst device 21 and includes a first catalyst region 15. Thus, when exhaust gas passes through the first catalyst device 11, a portion of the ammonia in the exhaust gas is decomposed by the first catalyst 12. Therefore, compared to conventional exhaust gas treatment systems, even when the exhaust gas temperature is low, the exhaust gas temperature rises due to the heat generated during the decomposition (oxidation) of ammonia in the first catalyst device, allowing for efficient decomposition of nitrous oxide in the second catalyst device 21. Furthermore, it prevents the ammonia concentration in the exhaust gas introduced into the second catalyst device 21 and the third catalyst device 31 from becoming excessively high, and efficiently decomposes nitrous oxide and nitrogen oxides.

[0167] In a first embodiment of the exhaust gas treatment system of the present invention, the first catalyst device 11 is disposed upstream of the second catalyst device 21 and the third catalyst device 31, and includes a virtual catalyst region 16. Therefore, even if exhaust gas passes through the first catalyst device 11, the remaining ammonia in the exhaust gas will not be decomposed by the virtual catalyst 13. Thus, in the second catalyst device 21 and the third catalyst device 31, ammonia can be used as a reducing agent when decomposing nitrous oxide and reducing nitrogen oxides, thereby efficiently decomposing nitrous oxide and nitrogen oxides. In addition, in the first catalyst device 11, even if the composition and / or flow rate of the exhaust gas changes, ammonia can be introduced into the second catalyst device 21 and the third catalyst device 31 in a certain proportion without decomposition, thereby efficiently decomposing nitrous oxide and nitrogen oxides.

[0168] In a first embodiment of the exhaust gas treatment system of the present invention, the first catalyst device 11 includes a first catalyst 12 and a virtual catalyst 13. Therefore, by not providing a bypass in the exhaust passage 10, ammonia can be introduced into the second catalyst device 21 and the third catalyst device 31 in a certain proportion without decomposition, thereby simplifying the device structure and saving space.

[0169] In a first embodiment of the exhaust gas treatment system of the present invention, the first catalyst device 11 includes a first catalyst 12 and a dummy catalyst 13, which are arranged in a direction orthogonal to the exhaust gas flow direction. The first catalyst 12 and the dummy catalyst 13 are respectively configured along the exhaust gas flow direction. Therefore, all exhaust gas passage paths in the first catalyst device 11 are parallel, thus ensuring equal pressure loss in any passage path. The ratio of the dummy catalyst 13 to the first catalyst 12 can be easily and accurately designed.

[0170] In a first embodiment of the exhaust gas treatment system of the present invention, if the first catalyst device 11 includes only the mixing unit 14, the concentration distribution of ammonia that is not decomposed in the exhaust gas and passes through the first catalyst device 11 is small. Therefore, the distance between the first catalyst device 11 and the second catalyst device 21 disposed downstream of the first catalyst device 11 (the length of the exhaust passage 10 between the first catalyst device 11 and the second catalyst device 21 disposed downstream of the first catalyst device) can be shortened. Furthermore, space in the exhaust gas treatment system 1 can be saved.

[0171] 2. Second Implementation Method

[0172] Reference Figure 4 A second embodiment of the exhaust treatment system 1 will be described. Furthermore, detailed descriptions of structures identical to those in the first embodiment of the exhaust treatment system 1 will be omitted.

[0173] The exhaust treatment system 1 of the second embodiment includes, from upstream to downstream, a third catalyst device 31, a first catalyst device 11, and a second catalyst device 21. In other words, the first catalyst device 11 is disposed downstream of the third catalyst device 31, and the second catalyst device 21 is disposed downstream of the first catalyst device 11.

[0174] 2.1. Effects

[0175] In a second embodiment of the exhaust gas treatment system of the present invention, a third catalyst device 31 is disposed upstream of the first catalyst device 11. That is, exhaust gas is introduced into the third catalyst device 31 before passing through the first catalyst device 11. Therefore, in the third catalyst device 31, ammonia in the exhaust gas can be used as a reducing agent, and nitrogen oxides can be decomposed efficiently. Furthermore, depending on the temperature of the exhaust gas, nitrogen oxides can be decomposed even more efficiently.

[0176] In a second embodiment of the exhaust gas treatment system of the present invention, a first catalyst device 11 is disposed upstream of a second catalyst device 21 and includes a first catalyst region 15. Thus, when exhaust gas passes through the first catalyst device 11, a portion of the ammonia in the exhaust gas is decomposed by the first catalyst 12.

[0177] Therefore, compared to previous exhaust treatment systems, even at low exhaust temperatures, the exhaust temperature rises due to the heat generated during the decomposition (oxidation) of ammonia in the first catalyst unit, allowing for efficient decomposition of nitrous oxide in the second catalyst unit 21. Furthermore, it prevents the ammonia concentration in the exhaust introduced into the second catalyst unit 21 from becoming excessively high, thus ensuring efficient decomposition of nitrous oxide.

[0178] In a second embodiment of the exhaust gas treatment system of the present invention, the first catalyst device 11 is disposed upstream of the second catalyst device 21 and includes a virtual catalyst region 16. Therefore, even if exhaust gas passes through the first catalyst device 11, the remaining ammonia in the exhaust gas will not be decomposed by the virtual catalyst 13. Thus, in the second catalyst device 21, ammonia can be used as a reducing agent for the decomposition of nitrous oxide, and nitrous oxide can be decomposed efficiently. In addition, even if the composition and / or flow rate of the exhaust gas changes, ammonia can be introduced into the second catalyst device 21 in a certain proportion without decomposition, and nitrous oxide can be decomposed efficiently.

[0179] In a second embodiment of the exhaust gas treatment system of the present invention, the first catalyst device 11 includes a first catalyst 12 and a virtual catalyst 13. Therefore, by not providing a bypass in the exhaust passage 10, a certain proportion of ammonia can be introduced into the second catalyst device 21 without decomposition, thereby simplifying the device structure and saving space.

[0180] In a second embodiment of the exhaust gas treatment system of the present invention, the first catalyst device 11 includes a first catalyst 12 and a virtual catalyst 13, which are arranged in a direction orthogonal to the exhaust gas flow direction. The first catalyst 12 and the virtual catalyst 13 are respectively configured along the exhaust gas flow direction. Therefore, all exhaust gas paths in the first catalyst device 11 are parallel, thus ensuring equal pressure loss in any path. The ratio of the virtual catalyst 13 to the first catalyst 12 can be easily and accurately designed.

[0181] In a second embodiment of the exhaust gas treatment system of the present invention, if the first catalyst device 11 includes only the mixing unit 14, the concentration distribution of ammonia that is not decomposed in the exhaust gas and passes through the first catalyst device 11 is small. Therefore, the distance between the first catalyst device 11 and the second catalyst device 21 disposed downstream of the first catalyst device 11 (the length of the exhaust passage 10 between the first catalyst device 11 and the second catalyst device 21 disposed downstream of the first catalyst device) can be shortened. Furthermore, space in the exhaust gas treatment system 1 can be saved.

[0182] 3. Third Implementation Method

[0183] Reference Figure 5 A third embodiment of the exhaust treatment system 1 will be described. Furthermore, detailed descriptions of structures identical to those in the first embodiment of the exhaust treatment system 1 will be omitted.

[0184] The exhaust treatment system 1 of the third embodiment includes, from upstream to downstream, a first catalyst device 11, a third catalyst device 31, and a second catalyst device 21. In other words, the third catalyst device 31 is disposed downstream of the first catalyst device 11, and the second catalyst device 21 is disposed downstream of the third catalyst device 31.

[0185] 3.1. Effects

[0186] In a third embodiment of the exhaust gas treatment system of the present invention, a first catalyst device 11 is disposed upstream of a second catalyst device 21 and includes a first catalyst region 15. Thus, when exhaust gas passes through the first catalyst device 11, a portion of the ammonia in the exhaust gas is decomposed by the first catalyst 12.

[0187] Therefore, compared to previous exhaust treatment systems, even at low exhaust temperatures, the exhaust temperature rises due to the heat generated during the decomposition (oxidation) of ammonia in the first catalyst unit, allowing for efficient decomposition of nitrous oxide in the second catalyst unit 21. Furthermore, it prevents excessively high ammonia concentrations in the exhaust introduced into the third catalyst unit 31 and the second catalyst unit 21, resulting in efficient decomposition of nitrogen oxides and nitrous oxide.

[0188] In a third embodiment of the exhaust gas treatment system of the present invention, the first catalyst device 11 is disposed upstream of the third catalyst device 31 and the second catalyst device 21, and includes a virtual catalyst region 16. Therefore, even if the exhaust gas passes through the first catalyst device 11, the remaining portion of ammonia in the exhaust gas will not be decomposed by the virtual catalyst 13. Thus, in the third catalyst device 31 and the second catalyst device 21, ammonia can be used as a reducing agent when reducing nitrogen oxides and decomposing nitrous oxide, thereby efficiently decomposing nitrogen oxides and nitrous oxide. In addition, in the first catalyst device 11, even if the composition and / or flow rate of the exhaust gas changes, ammonia can be introduced into the third catalyst device 31 and the second catalyst device 21 in a certain proportion without decomposition, thereby efficiently decomposing nitrogen oxides and nitrous oxide.

[0189] In a third embodiment of the exhaust gas treatment system of the present invention, the first catalyst device 11 includes a first catalyst 12 and a virtual catalyst 13. Therefore, by not providing a bypass in the exhaust passage 10, ammonia can be introduced into the third catalyst device 31 and the second catalyst device 21 in a certain proportion without decomposition, thereby simplifying the device structure and saving space.

[0190] In a third embodiment of the exhaust gas treatment system of the present invention, the first catalyst device 11 includes a first catalyst 12 and a virtual catalyst 13, which are arranged in a direction orthogonal to the exhaust gas flow direction. The first catalyst 12 and the virtual catalyst 13 are respectively configured along the exhaust gas flow direction. Therefore, all exhaust gas passage paths in the first catalyst device 11 are parallel, thus ensuring equal pressure loss in any passage path. The ratio of the virtual catalyst 13 to the first catalyst 12 can be easily and accurately designed.

[0191] In a third embodiment of the exhaust gas treatment system of the present invention, if the first catalyst device 11 includes only the mixing unit 14, the concentration distribution of ammonia that is not decomposed in the exhaust gas and passes through the first catalyst device 11 is small. Therefore, the distance between the first catalyst device 11 and the third catalyst device 31 disposed downstream of the first catalyst device 11 (the length of the exhaust passage 10 between the first catalyst device 11 and the third catalyst device 31 disposed downstream of the first catalyst device) can be shortened. Furthermore, space in the exhaust gas treatment system 1 can be saved.

[0192] 4. Variations

[0193] In the modified examples, the same reference numerals are used to denote components and steps identical to those in the first embodiment of the exhaust treatment system, and detailed descriptions are omitted. Furthermore, unless otherwise specified, the modified examples can achieve the same effects as the first embodiment of the exhaust treatment system. Moreover, the first to third embodiments of the exhaust treatment system and the modified examples can be appropriately combined.

[0194] [Variation Example 1]

[0195] In a first embodiment of the exhaust gas treatment system, an inorganic fiber sheet is used as the first carrier for the first active metal in the first catalyst 12, but this is not a limitation. Specifically, an inorganic oxide may also be used as the first carrier for the first active metal. Furthermore, in this case, an inorganic binder is not used.

[0196] Examples of inorganic oxides include: zeolite, titanium dioxide, aluminum oxide, zirconium oxide, and silicon dioxide.

[0197] Methods for loading the first active metal onto inorganic oxides include, for example, impregnation, co-precipitation, mixing, and alkoxide methods.

[0198] The first catalyst 12 may also include additives as needed.

[0199] The first catalyst 12 is obtained by loading a first active metal onto an inorganic oxide using the method described above, and then shaping the composition containing the first active metal and the inorganic oxide loaded with the first active metal into granules, a honeycomb structure, or the like by extrusion molding or the like.

[0200] The virtual catalyst 13, the second catalyst, and the third catalyst can also be obtained by the same method. In addition, the virtual catalyst 13 is obtained by forming a composition containing an inorganic oxide without the first active metal into granules, a honeycomb structure, or the like through extrusion molding or the like.

[0201] The first catalyst 12 and the dummy catalyst 13 manufactured as described above are difficult to separately fill within a single housing in the first catalyst region 15 and the dummy catalyst region 16. That is, the first catalyst 12 and the dummy catalyst 13 manufactured as described above cannot form a mixing unit 14. Therefore, when using the first catalyst 12 and the dummy catalyst 13 manufactured as described above, such as Figure 3 As shown, the first catalyst device 11 includes a first unit 17 and a virtual unit 18.

[0202] [Variation Example 2]

[0203] In a first embodiment of the exhaust treatment system, the first catalyst device 11 is, for example, as shown in the example... Figure 2 As shown, only the mixing unit 14 is included, or as... Figure 3 As shown, it includes a first unit 17 and a virtual unit 18, but is not limited thereto. Specifically, it may include a hybrid unit 14 and a first unit 17, or a hybrid unit 14 and a virtual unit 18, or a hybrid unit 14, a first unit 17, and a virtual unit 18.

[0204] [Variation Example 3]

[0205] In the first embodiment of the exhaust treatment system, and in other embodiments of the first catalyst device 11, such as Figure 3 As shown, the first unit 17 and the virtual unit 18 are arranged alternately along the width and height directions, but this is not a limitation. Specifically, the first unit 17 or the virtual unit 18 may be included only in the width direction, the first unit 17 or the virtual unit 18 may be included only in the height direction, or the first unit 17 or the virtual unit 18 may be included in a partially continuous manner in the width and / or height directions.

[0206] Furthermore, while the invention described is provided as an illustrative embodiment of the invention, it is merely an example and not intended to be limiting. Variations of the invention as understood by those skilled in the art are included in the following claims.

[0207] [Industry availability]

[0208] The exhaust treatment system of the present invention is suitable for treating exhaust gases from combustion devices (e.g., land engines, marine engines, etc.) that use ammonia fuel or fuels mixed with ammonia fuel in fossil fuels (e.g., gasoline, heavy oil), as well as exhaust gases from chemical plants or power plants.

[0209] Explanation of icon numbers

[0210] 1: Exhaust Treatment System

[0211] 11: First catalyst unit

[0212] 12: First catalyst

[0213] 13: Virtual Catalyst

[0214] 21: Second catalyst unit

[0215] 31: Third catalyst unit

Claims

1. An exhaust gas treatment system for treating exhaust gas containing ammonia, nitrous oxide, and nitrogen oxides, said exhaust gas treatment system comprising: An exhaust passage for the flow of the exhaust gas; A first catalyst device is separated in the exhaust passage and has a first catalyst for decomposing ammonia and a virtual catalyst for not decomposing ammonia. The second catalyst device is separated from the exhaust passage and has a second catalyst for the decomposition of nitrous oxide; as well as A third catalyst device is interposed in the exhaust passage and has a third catalyst for reducing nitrogen oxides. The first catalyst device is located upstream of the second catalyst device. The first catalyst comprises a first active metal for decomposing ammonia and a first support for supporting the first active metal. The virtual catalyst includes a virtual carrier that does not support the first active metal.

2. The exhaust treatment system of claim 1, wherein, The first catalyst and the virtual catalyst are arranged in a direction orthogonal to the flow direction of the exhaust gas. The first catalyst and the virtual catalyst are respectively configured to flow along the direction of the exhaust gas.

3. The exhaust treatment system of claim 1, wherein, The first catalyst device includes a mixing unit, in which the first catalyst and the dummy catalyst are alternately filled in a direction orthogonal to the flow direction of the exhaust gas. Multiple mixing units are arranged in a direction orthogonal to the flow direction of the exhaust gas.

4. The exhaust treatment system of claim 1, wherein, The first catalyst device includes a first unit filled only with the first catalyst and a virtual unit filled only with the virtual catalyst. The first unit and the virtual unit are arranged in multiple ways along a direction orthogonal to the flow direction of the exhaust gas.

5. The exhaust treatment system of any one of claims 1-4, wherein, The first catalyst and the virtual catalyst are each in the shape of a flat plate and / or a corrugated plate along the flow direction of the exhaust gas.

6. The exhaust treatment system of claim 5, wherein, The first carrier and the virtual carrier are respectively flat glass paper and / or corrugated glass paper along the flow direction of the exhaust.

7. The exhaust treatment system of any one of claims 1-4, wherein, The third catalyst device is located downstream of the second catalyst device.

8. The exhaust treatment system of any one of claims 1-4, wherein, The third catalyst device is located upstream of the first catalyst device.

9. The exhaust treatment system of any one of claims 1-4, wherein, The third catalyst device is disposed between the first catalyst device and the second catalyst device.

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