Method for producing catalyst and catalyst

Abstract

Disclosed are a method for manufacturing a catalyst and a catalyst for improving exhaust gas purification efficiency. The method includes: attaching a catalyst slurry containing at least a metal catalyst and water to a carrier (catalyst slurry attachment step (S110)); attaching water-absorbing polymer particles to the surface of the catalyst slurry (particle attachment step (S120)); expanding the particles to a predetermined size using the water contained in the catalyst slurry (expansion step (S130)); and calcining the carrier to which the catalyst slurry and particles are attached (calcination step (S150)).

Description

Technical Field

[0001] The present invention relates to a method for producing a catalyst to be installed in an exhaust pipe of a vehicle and the catalyst. Background Art

[0002] In order to remove hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NO x ), a three-way catalyst is installed in the exhaust pipe of a vehicle (for example, Patent Document 1). The three-way catalyst oxidizes hydrocarbons to form water and carbon dioxide (CO2), oxidizes carbon monoxide to form carbon dioxide, and reduces nitrogen oxides to form nitrogen (N2).

[0003] In addition, in recent years, engines capable of performing lean burn, in which fuel is burned at an air-fuel ratio leaner than the theoretical air-fuel ratio (stoichiometric ratio), have been developed. Compared with combustion under stoichiometric ratio, the amount of nitrogen oxides contained in the exhaust gas discharged from the engine during lean burn is higher. Therefore, a NOx filter is installed in the exhaust pipe of a vehicle equipped with an engine capable of performing lean burn. x Absorption storage reduction catalyst, the NO x The absorption storage reduction catalyst temporarily absorbs and stores nitrogen oxides, and reduces (purifies) the absorbed and stored nitrogen oxides at a predetermined timing.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-253447 Summary of the Invention

[0005] It is hoped that the development of a catalyst that can improve the utilization of the above three-way catalyst, NO x Technology that improves the efficiency of exhaust gas purification by catalysts such as absorption storage reduction catalysts.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for producing a catalyst and a catalyst capable of improving the purification efficiency of exhaust gas.

[0007] In order to solve the above-mentioned problems, the catalyst manufacturing method of the present invention includes: a step of attaching a catalyst slurry containing at least a metal catalyst and water to a carrier; a step of attaching particles of a water-absorbing polymer to the surface of the catalyst slurry; a step of using the water contained in the catalyst slurry to expand the particles to a predetermined size; and a step of calcining the carrier to which the catalyst slurry and particles are attached.

[0008] Alternatively, the carrier may have a plurality of units divided by partition walls, and in the process of attaching the catalyst slurry to the carrier, the catalyst slurry is supplied to at least one unit in the carrier, and in the process of attaching particles to the surface of the catalyst slurry, the unit supplied with the catalyst slurry is filled with a plurality of particles, and in the expansion process, the plurality of particles are expanded to a predetermined size using water contained in the catalyst slurry, and the catalyst slurry is pressed by the expanded plurality of particles.

[0009] Alternatively, the carrier may have a plurality of units divided by partition walls, and in the process of attaching the catalyst slurry to the carrier, the catalyst slurry is supplied to at least one unit in the carrier, and in the process of attaching particles to the surface of the catalyst slurry, a plurality of particles are supplied to the unit supplied with the catalyst slurry in a manner that allows the particles to be non-contact with each other, and in the expansion process, water contained in the catalyst slurry is absorbed by the particles.

[0010] In order to solve the above-mentioned problems, the catalyst of the present invention is produced by the above-mentioned method for producing a catalyst.

[0011] According to the present invention, the exhaust gas purification efficiency can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram showing the configuration of the engine system according to the first embodiment.

[0013] Figure 2 This is a flowchart showing the process flow of the method for producing the catalyst according to the first embodiment.

[0014] Figure 3a 、 Figure 3b 、 Figure 3c These are diagrams for explaining the catalyst slurry adhering step and the particle adhering step of the first embodiment.

[0015] Figure 4a 、 Figure 4b 、 Figure 4c 、 Figure 4d This is a diagram illustrating the interior of a cell for explaining the catalyst slurry adhering step, the particle adhering step, the expansion step, and the firing step of the first embodiment.

[0016] Figure 5 This is a flowchart showing the process flow of the method for producing a catalyst according to the second embodiment.

[0017] Figure 6a 、 Figure 6b 、 Figure 6c 、 Figure 6d It is a diagram illustrating the interior of a cell for explaining the catalyst slurry adhering step, the particle adhering step, the expansion step, and the firing step of the second embodiment.

[0018] Figure 7a 、 Figure 7b It is a diagram illustrating the interior of the cell after the particle attachment step of the modified example is performed.

[0019] (Explanation of Reference Numerals)

[0020] R water-absorbing particles (particles)

[0021] SL slurry layer (catalyst slurry)

[0022] S110 Catalyst slurry adhesion process

[0023] S120, S220 particle attachment process

[0024] S130 expansion process

[0025] S150 firing process

[0026] 130 Catalyst

[0027] 132 carrier

[0028] 134 partition wall

[0029] Unit 136 DETAILED DESCRIPTION

[0030] Below, preferred embodiments of the present invention are described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values ​​shown in these embodiments are merely illustrative for facilitating understanding of the invention and, unless otherwise specified, do not limit the invention. In this specification and the accompanying drawings, elements having substantially the same function or structure are denoted by the same reference numerals, and repeated descriptions are omitted. Elements not directly related to the present invention are omitted from the drawings.

[0031] [First embodiment]

[0032] Figure 1 1 is a schematic diagram showing the structure of the engine system 100 of the first embodiment. The engine system 100 is installed in a vehicle. Figure 1 As shown, the engine system 100 includes an engine 110 , an exhaust pipe 120 , a catalyst 130 , a filter 140 , and a muffler 150 .

[0033] The engine 110 is, for example, a gasoline engine. The engine 110 uses kinetic energy obtained by burning fuel to propel the vehicle. An exhaust pipe 120 is connected to the exhaust port of the engine 110 via an exhaust manifold. Exhaust gas discharged from the exhaust port of the engine 110 is guided to the exhaust pipe 120.

[0034] Catalyst 130 is installed in exhaust pipe 120. Catalyst 130 is a three-way catalyst (TWC). Catalyst 130 purifies (removes) hydrocarbons, carbon monoxide, and nitrogen oxides contained in the exhaust gas. Catalyst 130 includes a metal catalyst. The metal catalyst is one or more of platinum (Pt), palladium (Pd), and rhodium (Rh).

[0035] Filter 140 is installed in exhaust pipe 120 downstream of catalyst 130. In other words, filter 140 is installed in exhaust pipe 120 between catalyst 130 and muffler 150. Filter 140 is a GPF (Gasoline Particulate Filter). Filter 140 captures particulate matter (PM) contained in exhaust gas.

[0036] The exhaust gas, from which particulate matter has been removed by the filter 140 and purified by the catalyst 130, passes through the muffler 150 and is discharged to the outside.

[0037] [Method for Manufacturing Catalyst 130]

[0038] Next, a method for producing the catalyst 130 will be described. Figure 2 1 is a flowchart showing the process flow of the method for producing the catalyst 130 according to the first embodiment. Figure 2 As shown, the method for producing the catalyst 130 of the first embodiment includes a catalyst slurry adhering step (S110), a particle adhering step (S120), an expansion step (S130), a drying step (S140), and a firing step (S150).

[0039] [Catalyst slurry adhesion step (S110)]

[0040] The catalyst slurry adhering step (S110) is a step of adhering the catalyst slurry to the carrier to produce the slurry-adhered carrier 250. The catalyst slurry contains a metal catalyst, a binder, a base material, and water.

[0041] Figure 3a 、 Figure 3b 、 Figure 3c It is a diagram for explaining the catalyst slurry adhering step ( S110 ) and the particle adhering step ( S120 ) of the first embodiment. Figure 3a It is a diagram illustrating the carrier 132 . Figure 3b It is a diagram for explaining the catalyst slurry adhering step (S110). Figure 3c It is a diagram for explaining the particle adhering step (S120).

[0042] like Figure 3aAs shown, in this embodiment, the carrier 132 is a honeycomb structure having a cylindrical outer shape. The carrier 132 has a plurality of cells 136 divided by partition walls 134. The number of cells 136 is not limited.

[0043] like Figure 3b As shown, in the catalyst slurry attachment step (S110), the catalyst slurry is attached to the surface of the partition wall 134 of the unit 136 constituting the carrier 132 using the supply device 210. The supply device 210 includes a guide cylinder 212, a slurry supply unit 220, a suction unit 230, and a particle supply unit 240 (see Figure 3c ).

[0044] The guide cylinder 212 is a cylindrical member. The guide cylinder 212 is fitted onto one end of the carrier 132. The inner diameter of the guide cylinder 212 is slightly larger than the outer diameter of the carrier 132. The guide cylinder 212 is sized so that no gap is formed between the guide cylinder 212 and the carrier 132 when fitted onto the carrier 132.

[0045] The slurry supply unit 220 supplies catalyst slurry to the carrier 132 (unit 136) via the guide tube 212. In this embodiment, the slurry supply unit 220 includes a slurry storage unit 222, a slurry supply pipe 224, a slurry supply pump 226, and a slurry nozzle 228.

[0046] The slurry reservoir 222 stores catalyst slurry. A slurry supply pipe 224 connects the slurry reservoir 222 to the suction side of a slurry supply pump 226. The suction side of the slurry supply pump 226 is connected to the slurry reservoir 222 via the slurry supply pipe 224. The discharge side of the slurry supply pump 226 is connected to a slurry nozzle 228. The slurry nozzle 228 is connected to the guide tube 212. The slurry supply pump 226 draws the catalyst slurry stored in the slurry reservoir 222 and sprays it from the slurry nozzle 228 toward the carrier 132.

[0047] The suction unit 230 sucks the catalyst slurry from the other end of the carrier 132. In this embodiment, the suction unit 230 includes a suction cylinder 232, a suction pipe 234, and a suction pump 236.

[0048] The suction cylinder 232 is a cylindrical member. One end of the suction cylinder 232 is open, and the other end is closed. The opening of the suction cylinder 232 engages with the other end of the carrier 132. The opening of the suction cylinder 232 is slightly larger than the outer diameter of the carrier 132. When the suction cylinder 232 is engaged with the carrier 132, the size of the suction cylinder 232 is such that no gap is formed between the suction cylinder 232 and the carrier 132.

[0049] The suction pipe 234 connects the suction cylinder 232 and the suction pump 236. The suction side of the suction pump 236 is connected to the suction cylinder 232 via the suction pipe 234. The discharge side of the suction pump 236 is connected to the outside (for example, the slurry storage unit 222).

[0050] In the catalyst slurry attachment step (S110), a guide cylinder 212 is fitted on one end of the carrier 132, and a suction cylinder 232 is fitted on the other end. A slurry nozzle 228 is connected to the guide cylinder 212. The slurry supply pump 226 and the suction pump 236 are driven, and the carrier 132 is rotated (at the same time) by a rotating device (not shown). Figure 3b , indicated by dotted arrows). Thus, the catalyst slurry is supplied to the units 136 of the support 132 without omission.

[0051] Figure 4a 、 Figure 4b 、 Figure 4c 、 Figure 4d This is a diagram illustrating the interior of the unit 136 for explaining the catalyst slurry adhering step ( S110 ), the particle adhering step ( S120 ), the expansion step ( S130 ), and the firing step ( S150 ) of the first embodiment. Figure 4a This is a diagram illustrating the interior of the unit 136 after the catalyst slurry adhering step ( S110 ) is performed. Figure 4b This is a diagram illustrating the interior of the unit 136 after the particle adhering step ( S120 ) is performed. Figure 4c This is a diagram illustrating the interior of the cell 136 after the expansion step ( S130 ) is performed. Figure 4d This is a diagram illustrating the interior of the unit 136 after the firing step ( S150 ) is performed.

[0052] By performing the catalyst slurry attachment process (S110), the catalyst slurry is supplied to each unit 136 of the carrier 132, such as Figure 4a As shown, a layer of catalyst slurry (slurry layer SL) is formed on the surface of the partition wall 134 constituting the cell 136 .

[0053] Then, when the thickness of the slurry layer SL (the height from the surface of the partition wall 134 to the surface of the slurry layer SL) reaches a predetermined thickness, the slurry supply pump 226 and the suction pump 236 are stopped. In this way, the slurry-attached carrier 250 having the slurry layer SL formed on the surface of the partition wall 134 constituting the cell 136 is manufactured.

[0054] [Particle Adhesion Step (S120)]

[0055] The particle attachment step ( S120 ) is a step of attaching water-absorbing polymer (superabsorbent polymer) particles (hereinafter referred to as "water-absorbing particles") to the surface of the slurry layer SL of the slurry attachment carrier 250 . Water-absorbing polymers are also called superabsorbent polymers, superabsorbent resins, or polymer absorbents. An example of a water-absorbing polymer is sodium polyacrylate.

[0056] return Figure 3a 、 Figure 3b 、 Figure 3c To explain, such as Figure 3c As shown, in this embodiment, in the particle attachment step ( S120 ), the supply device 210 is used to fill the cells 136 of the slurry attachment carrier 250 with a plurality of water-absorbing particles.

[0057] The particle supply unit 240 supplies water-absorbing particles to the slurry-attached carrier 250 (carrier 132) via the guide tube 212. In this embodiment, the particle supply unit 240 includes a water-absorbing particle storage unit 242, a water-absorbing particle supply pipe 244, a feeder 246, and a water-absorbing particle nozzle 248.

[0058] The water-absorbing particle storage section 242 stores water-absorbing particles. A water-absorbing particle supply pipe 244 connects the water-absorbing particle storage section 242 to the inlet of a feeder 246. The inlet of the feeder 246 is connected to the water-absorbing particle storage section 242 via the water-absorbing particle supply pipe 244. The outlet of the feeder 246 is connected to a water-absorbing particle nozzle 248. The feeder 246 is, for example, a screw feeder. The water-absorbing particle nozzle 248 is connected to the guide cylinder 212. The feeder 246 supplies the water-absorbing particles stored in the water-absorbing particle storage section 242 to the slurry-attached carrier 250 via the water-absorbing particle nozzle 248.

[0059] In the particle adhering step ( S120 ), first, the slurry nozzle 228 is removed from the guide tube 212 . Next, the water-absorbing particle nozzle 248 is connected to the guide tube 212 in place of the slurry nozzle 228 .

[0060] Then, the feeder 246 is driven, and the slurry-attached carrier 250 is rotated by a rotating device (not shown) (in Figure 3c , indicated by dotted arrows). Thus, the water-absorbing particles are completely filled into the cells 136 of the slurry-attaching carrier 250. In the particle attachment step (S120) of this embodiment, the suction pump 236 is stopped.

[0061] By performing the particle attachment process (S120), the cell 136 is filled with water-absorbing particles R, such as Figure 4bAs shown, water-absorbing particles R are attached to the surface of the slurry layer SL. In this way, the particle attachment carrier 252 is manufactured, in which the water-absorbing particles R are attached to the surface of the slurry layer SL of the slurry attachment carrier 250. In the particle attachment step (S120) of this embodiment, the water-absorbing particles R are filled in the cell 136 so that the water-absorbing particles R are in contact with each other.

[0062] [Expansion Step (S130)]

[0063] The expansion step (S130) is a step of expanding the plurality of water-absorbing particles R to a predetermined size using water contained in the slurry layer SL (catalyst slurry). In the expansion step (S130), the particle-attached carrier 252 is left for a predetermined time.

[0064] By performing the expansion process (S130), the water-absorbing particles R absorb the water contained in the slurry layer SL and expand (swell). Figure 4c As shown, the slurry layer SL is pressed by the expanded water-absorbing particles R, and the water-absorbing particles R are embedded in the slurry layer SL. As a result, a slurry layer SL is formed on the surface of the slurry layer SL that is larger than the initial state (the slurry layer SL of the slurry attachment carrier 250, Figure 4c In this way, the particle expansion carrier 254 having the water-absorbing particles R embedded in the surface of the slurry layer SL is manufactured.

[0065] [Drying Step (S140)]

[0066] The drying step ( S140 ) is a step of drying the slurry layer SL (particle-expanded carrier 254 ) for a predetermined time.

[0067] [Firing process (S150)]

[0068] The firing step (S150) is a step of firing the particle expansion carrier 254 after the drying step (S140). By executing the firing step (S150), the water-absorbing particles R are burned and burned out. Figure 4d As shown, a catalyst 130 is manufactured in which a catalyst layer TL is formed inside the cell 136 (on the surface of the partition wall 134 ), and the catalyst layer TL has protrusions P and depressions Q on the surface.

[0069] Thus, the method for producing the catalyst 130 of this embodiment can produce the catalyst 130 by performing the catalyst slurry adhering step ( S110 ), the particle adhering step ( S120 ), the expansion step ( S130 ), the drying step ( S140 ), and the firing step ( S150 ).

[0070] [Size setting of water-absorbing particles R]

[0071] Next, the setting of the size (initial size m) and the filling rate n (bulk density) of the water-absorbing particles R filled in the particle attaching step ( S120 ) will be described.

[0072] First, the sizes of the protrusions P and recesses Q of the catalyst layer TL are determined based on the amount of exhaust gas discharged from the engine 110, the flow rate of the exhaust gas, the size of the catalyst 130, the target exhaust gas purification rate, and the target pressure loss of the catalyst 130. For example, to achieve a high target purification rate, the protrusions P and recesses Q are made larger, while to achieve a low target pressure loss, the protrusions P and recesses Q are made smaller. Furthermore, based on the determined sizes of the protrusions P and recesses Q, the size M of the water-absorbing particles R after expansion (after the expansion step ( S130 )) and the filling rate N of the water-absorbing particles R are derived.

[0073] The size M of the expanded water-absorbing particles R is derived based on the water content (water content) of the catalyst slurry (slurry layer SL), the initial (before water absorption) size m of the water-absorbing particles R, and the amount of water absorbed. Therefore, the initial size m of the water-absorbing particles R filled in the particle attachment step ( S120 ) is set based on the initial amount of water absorbed by the water-absorbing particles R, the water content of the catalyst slurry, and the derived size M of the expanded water-absorbing particles R.

[0074] In addition, the filling rate n of the water-absorbing particles R in the particle adhering step ( S120 ) is set based on the derived filling rate N of the water-absorbing particles R after expansion.

[0075] As described above, the method for manufacturing the catalyst 130 of this embodiment includes a particle attachment step ( S120 ) and an expansion step ( S130 ). Thus, within the cells 136 , the water-absorbing particles R absorb water contained in the slurry layer SL, causing the water-absorbing particles R to expand. Consequently, within the cells 136 , the water-absorbing particles R press against each other, allowing the water-absorbing particles R attached to the surface of the slurry layer SL to embed within the slurry layer SL. Thus, the method for manufacturing the catalyst 130 of this embodiment can form depressions Q and projections P (concavities) on the surface of the slurry layer SL using the expanded water-absorbing particles R.

[0076] Furthermore, by performing the firing step ( S150 ), the method for manufacturing catalyst 130 of this embodiment can fire the slurry layer SL while maintaining its uneven shape. Furthermore, since the water-absorbing particles R are formed using a water-absorbing polymer, the firing step ( S150 ) can completely burn out the water-absorbing particles R. Thus, the method for manufacturing catalyst 130 of this embodiment can manufacture catalyst 130 having a catalyst layer TL formed within cells 136 with protrusions P and depressions Q on its surface.

[0077] If the catalyst 130 manufactured in this way is installed in the exhaust pipe 120, the exhaust gas passes through the inside of the unit 136. That is, the exhaust gas passes through the inside of the unit 136 formed with the catalyst layer TL having protrusions P and depressions Q on the surface. As a result, unlike a unit having a flat surface of the catalyst layer, the catalyst 130 can create turbulent flow of the exhaust gas inside the unit 136. Therefore, the catalyst 130 can improve the diffusibility of the exhaust gas inside the unit 136. Therefore, unlike a unit having a flat surface of the catalyst layer, the catalyst 130 can reduce the exhaust gas that passes through the unit 136 without contacting (colliding with) the catalyst layer TL even though it is introduced into the unit 136. Therefore, the catalyst 130 can improve the purification efficiency of the exhaust gas.

[0078] As described above, in the particle attachment step ( S120 ), the supply device 210 fills the cell 136 with water-absorbing particles R. This allows the water-absorbing particles R attached to the surface of the slurry layer SL to be embedded in the slurry layer SL, thereby increasing the size of the protrusions P and depressions Q of the catalyst layer TL.

[0079] [Second embodiment]

[0080] In the particle attachment step ( S120 ) of the first embodiment, the cells 136 supplied with the catalyst slurry are filled with water-absorbing particles R. However, the cells 136 do not need to be filled with water-absorbing particles R as long as the water-absorbing particles R can be attached to the surface of the catalyst slurry.

[0081] Figure 5 1 is a flowchart showing the process flow of the method for manufacturing the catalyst 130 according to the second embodiment. Figure 5 As shown, the method for producing the catalyst 130 of the second embodiment includes a catalyst slurry adhering step (S110), a particle adhering step (S220), an expansion step (S130), a drying step (S140), and a calcining step (S150). Next, the particle adhering step (S220), which is substantially different from the method for producing the catalyst 130 of the first embodiment, will be described.

[0082] In the particle attachment step ( S220 ), the supply device 210 is used to supply a plurality of water-absorbing particles R to the cells 136 of the slurry attachment carrier 250 so that the water-absorbing particles R do not contact each other.

[0083] Figure 6a 、 Figure 6b 、 Figure 6c 、 Figure 6d This is a diagram illustrating the interior of the unit 136 for explaining the catalyst slurry adhering step ( S110 ), the particle adhering step ( S220 ), the expansion step ( S130 ), and the firing step ( S150 ) of the second embodiment. Figure 6aThis is a diagram illustrating the interior of the unit 136 after the catalyst slurry adhering step ( S110 ) is performed. Figure 6b It is a diagram illustrating the interior of the unit 136 after the particle adhering step ( S220 ) is performed. Figure 6c This is a diagram illustrating the interior of the cell 136 after the expansion step ( S130 ) is performed. Figure 6d This is a diagram illustrating the interior of the unit 136 after the firing step ( S150 ) is performed.

[0084] like Figure 6a As shown, in the second embodiment, by performing the catalyst slurry adhering step ( S110 ), similarly to the first embodiment, a slurry adhering carrier 250 having a slurry layer SL formed on the surface of the partition wall 134 constituting the cell 136 is manufactured.

[0085] Then, in the particle attachment step (S220), first, the slurry nozzle 228 is removed from the guide tube 212. Next, the water-absorbing particle nozzle 248 (see FIG. 24) is connected to the guide tube 212 instead of the slurry nozzle 228. Figure 3b 、 Figure 3c ).

[0086] Then, the feeder 246 and the suction pump 236 are driven, and the slurry-attached carrier 250 is rotated by a rotating device (not shown). As a result, the water-absorbing particles R are supplied to the cells 136 of the slurry-attached carrier 250 without omission. In the second embodiment, the size of the water-absorbing particles R supplied to the cells 136 is smaller than the distance between the slurry layers SL.

[0087] By performing the particle attachment process (S220), water-absorbing particles R are supplied to the unit 136, such as Figure 6b As shown, the water-absorbing particles R are attached to the surface of the slurry layer SL in a manner spaced apart from each other. Specifically, the surface of the slurry layer SL includes areas where the water-absorbing particles R are attached and areas where the water-absorbing particles R are not attached. In this manner, a particle attachment carrier 262 is manufactured, in which the water-absorbing particles R are attached to the surface of the slurry layer SL of the slurry attachment carrier 250.

[0088] Then, when the expansion step (S130) is performed, the water-absorbed particles R absorb the water contained in the slurry layer SL (catalyst slurry). Figure 6c As shown, the areas of the surface of the slurry layer SL where the water-absorbing particles R are attached absorb water, forming areas on the surface of the slurry layer SL that are more recessed than in the initial state (the slurry layer SL of the slurry-attached carrier 250). In this way, a particle expansion carrier 264 is produced in which a portion of the water-absorbing particles R is embedded in the surface of the slurry layer SL.

[0089] Then, if the drying step (S140) and the firing step (S150) are performed, the water-absorbing particles R are burned and burnt out. Figure 6d As shown, a catalyst 130 is manufactured in which a catalyst layer TL having a depressed portion Q on its surface is formed inside a cell 136 (on the surface of a partition wall 134 ).

[0090] As described above, the method for manufacturing the catalyst 130 of the second embodiment includes a particle attachment step (S220) and an expansion step (S130). Thus, the water-absorbing particles R can form depressions Q on the surface of the slurry layer SL. Furthermore, the method for manufacturing the catalyst 130 of the second embodiment can fire the slurry layer SL while maintaining the depressions Q by performing the firing step (S150). Furthermore, since the water-absorbing particles R are formed using a water-absorbing polymer, the water-absorbing particles R can be burned out by performing the firing step (S150). Thus, the method for manufacturing the catalyst 130 of the second embodiment can manufacture a catalyst 130 having a catalyst layer TL having depressions Q on its surface formed inside the cell 136. Therefore, the catalyst 130 manufactured by the method for manufacturing the catalyst 130 of the second embodiment can improve the exhaust gas purification efficiency.

[0091] Furthermore, compared to the first embodiment, the method for producing the catalyst 130 of the second embodiment can produce a catalyst 130 having a catalyst layer TL having a gentle surface irregularity.

[0092] The above, while referring to the attached Figure 1 While the preferred embodiment of the present invention is described, it is understood that the present invention is not limited to this embodiment. It is obvious that a person skilled in the art can think of various changes or modifications within the scope of the claims, and it should be understood that these also fall within the technical scope of the present invention.

[0093] In addition, in the above embodiment, the catalyst 130 is exemplified as a three-way catalyst. However, the catalyst 130 may also be other catalysts, such as NO x Absorption storage reduction catalyst.

[0094] In the above embodiment, the case where the carrier 132 is a honeycomb structure is exemplified. However, the shape of the carrier 132 is not limited.

[0095] In the above embodiment, the catalyst slurry adhering step ( S110 ) is described as adhering the catalyst slurry to all cells 136 provided on the carrier 132 . However, the catalyst slurry adhering step ( S110 ) only requires adhering the catalyst slurry to at least one cell 136 on the carrier 132 .

[0096] In the particle attaching step (S120) of the first embodiment, the water-absorbing particles R are filled into the cells 136 so that the water-absorbing particles R are in contact with each other. However, in the particle attaching step (S120), the water-absorbing particles R may be filled into the cells 136 so that the water-absorbing particles R are not in contact with each other.

[0097] Figure 7a 、 Figure 7b 1 is a diagram illustrating the interior of the unit 136 after executing the particle attachment step (S120) of the modified example. Figure 7a As shown, the particle attachment step (S120) can fill the cells 136 with water-absorbing particles R in a single layer. In this case, the water-absorbing particles R may or may not be in contact with each other. In this case, the size of the water-absorbing particles R can be substantially the same as the distance between the slurry layers SL.

[0098] In the particle attachment step (S120) of the first embodiment, the case where all the water-absorbing particles R are in contact with the surface of the slurry layer SL is exemplified. Figure 7b As shown, among the filled water-absorbing particles R, there may be water-absorbing particles R that are not in contact with the surface of the slurry layer SL.

[0099] In the particle attachment step (S120) of the first embodiment described above, the water-absorbing particles R are filled over the entire length of the cells 136 of the slurry attachment carrier 250. However, the particle attachment step (S120) of the first embodiment may be performed first to fill a portion of the cells 136 of the slurry attachment carrier 250 with the water-absorbing particles R, and then the particle attachment step (S220) of the second embodiment may be performed to supply the water-absorbing particles R to the remaining portion.

[0100] In the above embodiment, the particle supply unit 240 of the supply device 210 is illustrated as including the feeder 246. However, the particle supply unit 240 may not include the feeder 246. In this case, the slurry-attached carrier 250 may be arranged so that one end thereof is located above the other end thereof, and the water-absorbing particle reservoir 242 is positioned above the water-absorbing particle nozzle 248, so that the water-absorbing particles R fall from the water-absorbing particle reservoir 242 toward the slurry-attached carrier 250 under their own weight.

[0101] Industrial availability

[0102] The present invention can be used for a method for producing a catalyst and a catalyst to be installed in an exhaust pipe of a vehicle.

Claims

1. A method for producing a catalyst, comprising: a step of attaching a catalyst slurry containing at least a metal catalyst and water to a carrier; a step of attaching water-absorbing polymer particles to the surface of the catalyst slurry; a step of using water contained in the catalyst slurry to expand the particles to form irregularities on the surface of the catalyst slurry; and a step of firing the support to which the catalyst slurry and the particles are attached.

2. The method for producing a catalyst according to claim 1, wherein The carrier has a plurality of cells divided by partition walls, In the step of attaching the catalyst slurry to the carrier, the catalyst slurry is supplied to at least one of the cells in the carrier. In the step of attaching the particles to the surface of the catalyst slurry, the cell supplied with the catalyst slurry is filled with a plurality of the particles so that the particles are in contact with each other. In the expansion step, the plurality of particles are expanded to a predetermined size using water contained in the catalyst slurry, and the catalyst slurry is pressed by the expanded plurality of particles.

3. The method for producing a catalyst according to claim 1, wherein The carrier has a plurality of cells divided by partition walls, In the step of attaching the catalyst slurry to the carrier, the catalyst slurry is supplied to at least one of the cells in the carrier. In the step of attaching the particles to the surface of the catalyst slurry, a plurality of the particles are supplied to the unit to which the catalyst slurry is supplied so that the particles are not in contact with each other. In the expansion step, the particles absorb water contained in the catalyst slurry. A catalyst produced by the method for producing a catalyst according to any one of claims 1 to 3.

Images