JP2011230016A - Substrate of catalyst carrier for gasoline engine exhaust emission control system and method of producing catalyst carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that a honeycomb structure made of ceramic or a stainless thin sheet is generally used as a substrate of a catalyst carrier for a gasoline engine exhaust emission control system, however the substrate made of ceramic is easily broken, the substrate made of the stainless thin sheet cannot be produced inexpensively and, in addition, the substrate is difficult to produce compactly.SOLUTION: A method of producing catalyst carrier for a gasoline engine exhaust emission control system includes the processes of: preparing the substrate of the catalyst carrier by using a porous body made by sintering layered material of a plurality of metal nets; and forming an alumina thin layer in which the catalytic substance is dispersed and carried, on the surface of the substrate.

Description

  TECHNICAL FIELD The present invention relates to a base material for a catalyst carrier used in exhaust gas purification apparatuses for automobiles and two-wheeled vehicles driven by a gasoline engine, and gasoline that replaces a commonly used stainless steel thin plate and ceramic honeycomb structure. The present invention relates to the production of a catalyst carrier and a catalyst carrier of an engine exhaust gas purification device.

  Currently, for exhaust gas purification treatment of automobiles and motorcycles driven by a gasoline engine, a honeycomb structure made of ceramic or stainless steel sheet is used as a base material of the catalyst support, and a linear flow is made in the catalyst support. Mainly, a path is provided, and exhaust gas is allowed to pass therethrough to bring the exhaust gas into contact with a catalytic substance to obtain a catalytic reaction.

  In a conventional catalyst carrier substrate, it is indispensable to lengthen or narrow the exhaust gas flow path in order to obtain a sufficient catalytic reaction, and it is difficult to form the substrate compactly or to be manufactured. There was a problem that the cost increased. Then, when the prior application regarding the base material which solves these was investigated, literature was not found.

  The problem to be solved is that, in order to obtain a sufficient catalytic reaction, it is indispensable to lengthen or narrow the exhaust gas flow path in the conventional catalyst carrier base material. It is difficult to mold or the manufacturing cost increases.

  The base material of the catalyst carrier of the exhaust gas purifying apparatus for a gasoline engine according to the present invention is mainly characterized in that a porous body obtained by sintering a material in which a plurality of metal meshes are laminated is used as the base material of the catalyst carrier.

  The present invention can suppress pressure loss when exhaust gas passes by sintering as a base material of a catalyst carrier by using a relatively coarse metal mesh as a raw material as compared with a conventional material. There is an advantage that the passing flow path can be easily narrowed.

  In addition, the flow path through which the exhaust gas passes is curved in three dimensions to improve the catalytic reaction efficiency by increasing the possibility of contact between the exhaust gas and the catalyst substance, and as a result, the substrate can be made compact. There are advantages of reducing manufacturing costs and saving valuable catalyst material.

  In addition, since the base material of the catalyst carrier of the exhaust gas purifying apparatus for a gasoline engine of the present invention is a plate-like sintered wire mesh, there is a degree of freedom in forming by cutting and bending. It is possible to adjust the thickness of the entire catalyst carrier relatively easily. For example, a double-structured exhaust can be achieved by installing a catalyst carrier processed with a reduction catalyst, for example, upstream, through which exhaust gas passes, and a catalyst carrier processed with an oxidation catalyst downstream. It is possible to provide a gas purification device, and it is possible to secure a degree of freedom such that a plurality of base materials are alternately stacked to form a multiple structure, or the amount of catalyst material supported is changed for each base material.

1A to 1C are diagrams showing the results of an experiment for confirming the effect of the present invention.

  The present invention can be implemented in the following forms, for example. The base material of the catalyst carrier of the exhaust gas purifying apparatus for a gasoline engine of the present invention is obtained by sintering a material in which a plurality of wire meshes are laminated and integrating them into a plate-like porous body. A catalyst carrier used for a gasoline engine exhaust gas purification device is manufactured by forming an alumina thin layer on which a catalyst substance is dispersed and supported on the surface of the catalyst carrier.

  The base material of the catalyst carrier of the exhaust gas purifying apparatus for gasoline engines of the present invention ensures a large surface area compared to a plate of the same size by using a porous sintered wire mesh as the base material of the catalyst carrier. In addition, there is an advantage that it is possible to make a combination of apertures that are varied by using a wire mesh having different aperture diameters.

  Moreover, the reason for integrating the materials made by laminating a plurality of wire meshes by sintering is that the rigidity can be increased, and the wire rods in contact with each other, or the wire meshes are firmly connected to each other to position the wire rods. This is to prevent a deviation and ensure a stable opening.

  The wire mesh used as the base material for the catalyst carrier is preferably made of, for example, a stainless material having excellent corrosion resistance and heat resistance as a main material. A wire mesh made of iron or an iron alloy material may be used, but similarly, a material considering corrosion resistance and heat resistance is preferable.

  Moreover, it is desirable that the wire mesh used as the base material of the catalyst carrier is in the range of 6 to 20 mesh, and the opening diameter of each wire mesh is in the range of 0.5 mm to 2.5 mm. This is because the exhaust gas passage resistance is suppressed as much as possible, and the possibility of contact with the catalyst substance is increased to increase the catalyst efficiency.

(Manufacturing)
SUS316 wire mesh 20 mesh (wire diameter 0.4 mm, aperture 0.87 mm) and 16 mesh (wire diameter 0.45 mm, aperture 1.1 mm) are 16 mesh, 20 mesh, 16 mesh, 20 mesh, 16 The base material 1 of the catalyst support body which is a plate-shaped porous body was manufactured by laminating 5 sheets in the order of the mesh and sintering the metal meshes at about 1200 to 1300 ° C. under vacuum and pressure in a vacuum heat treatment furnace. . This is shown in FIG.

  Similarly, SUS316 wire mesh 16 mesh (wire diameter 0.45 mm, opening 1.1 mm) and 10 mesh (wire diameter 0.57 mm, opening 2.0 mm) 10 mesh, 16 mesh, 10 mesh, 16 The base material 2 of the catalyst carrier that is a plate-like porous body is obtained by laminating five meshes in the order of 10 mesh and sintering the metal meshes at about 1200 to 1300 ° C. under vacuum and pressure in a vacuum heat treatment furnace. Manufactured. This is shown in FIG.

Furthermore, similarly, SUS316 wire mesh 16 mesh (wire diameter 0.45 mm, aperture 1.1 mm) and 8 mesh (wire diameter 0.8 mm, aperture 2.4 mm) are 8 mesh, 16 mesh, 8 mesh. The base of the catalyst carrier, which is a plate-like porous body, is formed by laminating 5 sheets in the order of 16 mesh and 8 mesh and sintering the metal meshes at about 1200 to 1300 ° C. under vacuum and pressure in a vacuum heat treatment furnace. Material 3 was produced. This is shown in FIG.
(Confirmation and implementation)

  The base materials 1 to 3 of the catalyst carrier of the present invention produced as described above are cut into a disc shape having a diameter of 40 mm, and then the surface is roughened by shot-blasting, which is generally performed thereafter. The oxidation catalyst processing, that is, the alumina sol solution to which palladium nitrate was added was applied to the substrate and dried, followed by firing at about 650 ° C. in an air atmosphere.

  Further, in the substrates 1 to 3, the supported catalyst was only palladium, and the supported amount was 2 (%) of palladium with respect to the alumina 100 by weight ratio. In the supporting method, palladium nitrate is added to an alumina sol solution and applied to the base materials (1 to 3), followed by firing.

  Applying the above-mentioned three kinds of base materials 1 to 3 to Honda GX120T1 (2009) with engine displacement of 3920-3950 rpm at the time of testing at 118 cc, single cylinder, output 2.6 KW / 3600 rpm The catalyst performance was tested.

  1 (a) to 1 (c), the “air input amount” means that the engine exhaust gas used in the test did not have enough oxygen necessary for oxidation, so air was supplied to obtain oxygen. The ratio to the displacement is shown. The “exhaust gas temperature” indicates the temperature of the exhaust gas immediately after passing through the catalyst carrier. The measured values of “CO (%)” and “HC (ppm)” are average values of values measured five times.

  From the above test, the effectiveness of the present invention was confirmed as shown in FIG. Furthermore, it has been found that the substrate can be made more compact than a commonly used honeycomb structure substrate.

Claims (4)

  A base material for a catalyst carrier of an exhaust gas purifying apparatus for a gasoline engine, which is made of a porous body obtained by sintering a material in which a plurality of metal meshes are laminated.   2. The exhaust gas purification device for a gasoline engine according to claim 1, wherein the individual metal meshes to be laminated are 6 mesh to 20 mesh, and the hole diameters of the metal meshes are in the range of 0.5 to 2.5 mm. Catalyst carrier substrate   The base material of the catalyst carrier of the exhaust gas purification apparatus for a gasoline engine according to claim 1 or 2, wherein a main material of the wire mesh to be laminated is stainless steel, iron or iron alloy material.   4. A gasoline engine for producing an exhaust gas purifying apparatus for a gasoline engine according to any one of claims 1 to 3, wherein a thin layer of alumina carrying a catalyst material in a dispersed manner is formed on the surface of the base material of the catalyst carrier. A method for producing a catalyst carrier of an exhaust gas purification device.

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