DE112012001175T5 - Catalyst device for exhaust gas purification - Google Patents

Abstract

An object of the present invention is to provide a catalyst device for exhaust gas purification which has a high durability against vibration and high temperature and which can suppress the peeling of the catalyst layer from the catalyst carrier (P) during use, and the metallic one after use Catalyst can recover easily. According to the present invention, there is provided an exhaust gas purification catalyst device comprising a catalyst support member (1) on which a metallic exhaust gas purification catalyst is carried, characterized in that the catalyst support member (1) is made of a sheet-like catalyst carrier (P) by a wet paper making process and that the metallic catalyst is carried as a catalyst layer on the surfaces of the sheet-like catalyst carrier (P) after the sheet-like catalyst carrier (P) has been fired.

Description

FIELD OF THE INVENTION

The present invention relates to a catalyst device for exhaust gas purification comprising a catalyst support member for carrying thereon a metallic catalyst for exhaust gas purification.

DESCRIPTION OF THE PRIOR ART

The exhaust gas purification catalyst device for purifying the exhaust gas from an engine of a vehicle includes a catalyst carrier member (catalyst carrier) for carrying thereon a noble metal as a catalyst such as platinum, rhodium, palladium and so forth. Especially in general application machines for motorcycles and portable electric generators, etc., a metallic honeycomb structure having a high durability against a severe engine vibration and a high exhaust gas temperature has been mainly used as a catalyst carrier on the surface of which a catalyst layer is applied.

However, because the surfaces of the metallic honeycomb structure are smooth, and therefore, the adhesion of the catalyst layer to the metallic honeycomb structure is insufficient, in the prior art metal honeycomb structure catalyst device, it is feared that the catalyst layer coated on the metallic substrate would it would be peeled off. Various prior art agents for suppressing the peeling of the catalyst layer from the metallic carrier have been proposed. For example, micro projections are formed on the surfaces of the metallic honeycomb structure to clamp the catalyst layer as disclosed in the below-mentioned patent documents 1 and 2, and a metallic oxide coating for clamping the catalyst layer is formed on the surfaces of the metallic honeycomb structure as shown in FIG is disclosed below Patent Document 3.

DOCUMENTS OF THE PRIOR ART

PATENT DOCUMENTS

• Patent Document 1: JP 2004-169111 A
• Patent Document 2: JP 08-299808 A
• Patent Document 3: JP 06-71185 A

DISCLOSURE OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

However, since it is necessary to form means to prevent peeling of the catalyst layer on the catalyst support member (e.g., by microprojection or metal oxide coating), the manufacturing steps and hence the manufacturing cost would be increased. Although it is possible to have a catalyst device which can surely prevent peeling or separation of the metallic catalyst from the catalyst support member, in which case the catalyst support member is made of materials other than metal having high durability against vibration or high temperature, and On the other hand, even if the metallic catalyst is contained inside the catalyst support member, there would be another problem even in this case that it is very difficult to recover the metallic catalyst when the exhaust gas purification catalyst apparatus is scrapped after use.

It is therefore an object of the present invention to provide a catalyst device for exhaust gas purification which has high durability against vibration and high temperature and which can suppress the peeling of the catalyst layer from the catalyst carrier during use and which easily makes the metallic catalyst after use can win back.

MEANS OF SOLVING THE PROBLEMS

In order to achieve the above-mentioned object, according to the present invention as claimed in claim 1, there is provided a catalyst device for exhaust gas purification comprising a catalyst support member on which a metallic catalyst for exhaust purification is carried, characterized in that the catalyst support member is formed of a sheet-like catalyst carrier passing through a wet papermaking process has been prepared and that the metallic catalyst is carried as a catalyst layer on the surfaces of the film-like catalyst carrier after the film-like catalyst carrier has been fired.

The present invention according to claim 2 is a catalyst device for exhaust gas purification according to claim 1, wherein the film-like catalyst carrier contains ceramic powder and alumina / silica fibers.

The present invention according to claim 3 is a catalyst device for exhaust gas purification according to claim 1, wherein the ceramic powder contains alumina.

The present invention according to claim 4 is a catalyst device for exhaust gas purification according to claim 3, wherein the weight ratio of the alumina / silica fibers to the ceramic powder of the alumina contained in the catalyst support member is within a range of 0.2 to 2.5.

The present invention according to claim 5 is a catalyst device for exhaust gas purification according to any one of claims 1 to 4, wherein the firing temperature is within a range of 1450 to 1550 ° C.

The present invention according to claim 6 is a catalyst device for exhaust gas purification according to any one of claims 1 to 5, wherein the catalyst support member is produced by a film-forming step to make the paper of the sheet-like catalyst carrier of flakes by adding a flocculant into a slurry of a predetermined amount of water, added with predetermined fibers and binders is added; and by a firing step for firing the sheet-like catalyst carrier obtained in the film-forming step; and by a step of applying the metallic catalyst to apply the metallic catalyst to the surfaces of the catalyst carrier member obtained in the firing step.

The present invention of claim 7 is a catalyst device for exhaust gas purification according to any one of claims 1 to 6, wherein the catalyst support member has a honeycomb structure formed by adhering a corrugated foil-like catalyst support on at least one surface of a flat sheet-like catalyst support and by winding the catalyst support on a Roll is formed.

EFFECTS OF THE INVENTION

Since the exhaust gas purification catalytic device according to the present invention comprises a catalyst support member formed of a sheet-like catalyst carrier prepared by a wet paper-making method, and the metallic catalyst is carried as a catalyst layer on the surfaces of the catalyst support member after the catalyst support member has been fired For example, it is possible to have high durability against vibration or high temperature, and to suppress peeling of the catalyst layer from the catalyst support member in use and to easily recover the metallic catalyst after use.

BRIEF DESCRIPTION OF THE DRAWINGS

1 (a) and 1 (b) A schematic perspective view (a) and a plan view (b) showing a catalyst support member used for the exhaust gas purification catalyst device of the present invention;

2 A schematic view showing the manufacturing process of a film-like catalyst carrier used for the preparation of the catalyst carrier member;

3 (a) to 3 (d) Schematic views showing the manufacturing steps of the honeycomb structure of the catalyst support member used for the exhaust gas purification catalyst apparatus of the present invention;

4 A flowchart showing the manufacturing steps of the catalyst support member used for the exhaust gas purification catalyst apparatus of the present invention;

5 A graph to compare the surface roughness of the catalyst support member of the present invention with those made of ceramics and metal in the prior art; and

6 A graph to compare the peeling rate of the catalyst support member of the present invention with that of support members made of metal of the prior art.

A PREFERRED EMBODIMENT FOR CARRYING OUT THE INVENTION

A preferred embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

The exhaust gas purification catalyst device of the present invention is one used to treat exhaust gases generated from general machinery such as e.g. B. from motorcycles and portable electric generators, etc., to be cleaned, and it comprises a cylindrical catalyst carrier member (catalyst carrier) 1 with a honeycomb structure. The catalyst carrier 1 is first prepared by using a film-like (paper-like) catalyst support P using the outturn-machining method (see 2 ), then by the obtained film-like catalyst carrier P is formed into a rolled configuration having a honeycomb structure by firing the rolled catalyst carrier and finally applying the catalyst layers to the surfaces of the rolled honeycomb carrier structure.

The method of manufacturing the exhaust gas purification apparatus 1 of the present invention will be described with reference to the flowchart 4 described.

First of all, an aqueous solution is prepared by adding ceramic powders, predetermined fibers (refractory fibers) including alumina / silica fibers, inorganic binders, and a pore-controlling agent, etc. into a predetermined amount of water to prepare a slurry in which the Additives are evenly distributed (step S1 of the slurry production). Then, flakes are formed by adding flocculant to the slurry (step S2 of flocculation), and then the sheet-like (paper-like) porous structure (step S3 of film production) is formed by papermaking from the flocs.

In the present invention, the ceramic powder comprises alumina and the weight ratio of the alumina / silica fibers to the ceramic powder of the alumina contained in the catalyst support member 1 is included (ie

Weight ratio of alumina-silica fibers / alumina containing ceramic powder) is set within a range of 0.2 to 2.5.

The heat-resistant fibers include amorphous ceramics made of the main components of silica and alumina, which are made into a film-like catalyst carrier P by the wet paper-making method. Other heat-resistant fiber materials, e.g. Organic fibers such as aramid fibers can be used if they are chemically and physically stable and if they can obtain a high strength structure of entangled, interwoven fibers in the papermaking step. In addition, it is possible to prepare the paper-like catalyst carrier P from glass fibers or carbon fibers having high heat resistance and chemically and physically stable properties by the wet paper making method.

The flocculant to form the floc contains a high molecular flocculant and metallic cations and has a strong electrical charge. Therefore, the flocculant neutralizes the electrical charges in an aqueous solution of fibers that interact with each other with a force of impact and forces the fibers to become entangled. The high molecular flocculant tends to penetrate into the interstices between the fibers, causing the bonding force to increase. On the other hand, alum, aluminum sulfate, etc. containing Al ³⁺ cations in their aqueous solution are used as metallic cations.

As in 2 1, a predetermined thickness of the sheet-like catalyst carrier P according to the present invention is prepared by containing a predetermined amount of the flocs containing predetermined fibers and binder, etc. (flocs are formed via the step S1 of preparation of the slurry and the step S2 of flocculation manufactured), in a storage tank container 2 are included, and then adding liquid in the tank 2 using a Rundsiebzylnders 3 (ie, a cylindrical mesh member to make a constant amount of slurry into a roll 4 extracted), which is rotated at a position near the liquid level, is scooped out. This film-like catalyst carrier P is continuously from the roll 4 to a roller press 5 transferred and adjusted to a desired thickness by applying a predetermined pressure on the roller press 5 is exercised.

The film-like catalyst support P passing through the roller press 5 has been pressed and has a predetermined thickness (step 3 of the film production) is continuously to a drying machine 6 guided and dried during the transmission path thereby (drying step S4). The dried film-like catalyst support P is then passed through a rewinder 7 continuously wound. Thus, a predetermined amount of the sheet-like catalyst carrier P can be obtained. This film-like catalyst support P then becomes a honeycomb catalyst support member 1' of porous structure by rolling a flat sheet-like catalyst carrier Pa and a corrugated sheet-like catalyst carrier together to a honeycomb structure in a manner as described later (production step S5, see FIG 3 ). Finally, the honeycomb catalyst carrier element becomes 1' fired to the catalyst support element 1 having a porous structure (firing step S6, see 1 ). So far, at this stage, just after the baking step S6, no precious metal is still present as the catalyst metal on the catalyst carrier element 1 been applied.

In the manufacturing step S5, the sheet-like catalyst carrier P produced by the rewinder 7 has been wound up, produced by two types of films; one is a flat film-like catalyst carrier Pa and the other is a corrugated film-like catalyst carrier Pb, as shown in FIG 3 (a) is shown. A predetermined length of the corrugated foil-like catalyst carrier Pb is adhered by adhesive, etc., to at least one surface of the rectilinear sheet-like catalyst carrier Pa, as shown in FIG 3 (b) is shown. As in 3 (c) Then, the adhered sheet-like catalyst supports Pa, Pb are wound up around a rolled honeycomb catalyst element 1' in the pre-combustion state ( 3 (d) ).

The honeycomb catalyst carrier element 1 ( 1 ) can be obtained by using the honeycomb catalyst element obtained in the prebake state 1 ( 3 (d) ) in the manufacturing step S5 z. B. at a temperature of 1,450 ~ 1,550 ° C is fired (baking step S6). 5 shows comparative results of the surface roughness of the honeycomb catalyst support member 1 U.S. Patent No. 4,876,135, which has been prepared according to the present invention, a prior art ceramic honeycomb catalyst support member and a prior art metallic honeycomb catalyst support member. How out 5 can be seen, the surface roughness of the honeycomb catalyst support member 1 of the present invention about 5.916 (μm) (central bar in FIG 5 On the other hand, the surface roughness of the prior art ceramic honeycomb catalyst support member is 3.576 (μm) (left bar in FIG 5 ) or the metallic honeycomb catalyst carrier element according to the prior art 0.227 (μm) (right bar of the graph in FIG 5 ). It can be clearly understood that the surface roughness of the honeycomb catalyst carrier element 1 of the present invention is greater than that of the prior art ceramic and metallic honeycomb catalyst support members.

Then the surface becomes 1a the honeycomb catalyst carrier element 1 obtained by the firing step S6 having a catalyst layer prepared thereon for carrying thereon the noble metal metallic catalyst (e.g., platinum, rhodium, palladium, etc.) (step S7 for supporting the metallic catalyst). In the step of supporting the metallic catalyst, the slurry containing the metallic catalyst (noble metals as catalyst) and the binders is applied to the surface 1a the honeycomb catalyst carrier element 1 applied by the firing step S6, and the honeycomb catalyst support member 1 is heat treated at about 600 ° C to solidify the binders and thus the catalyst layer on the surface 1a the honeycomb catalyst carrier element 1 to secure.

The technical advantages of the honeycomb catalyst carrier element 1 The present invention will be described in comparison with the prior art metal catalyst support member. Samples (outer diameter: 30 mm, length 20 mm) of the honeycomb catalyst carrier element 1 The present invention and the prior art metallic catalyst support member were prepared and the slurry containing the metallic catalyst (precious metals as catalysts) and the binder was applied to the surfaces of the samples and both samples were heat treated at about 600 ° C. to solidify the binders and thus to secure the catalyst layer to the surface of the samples.

The weight of the catalyst layer coated on the surface of the catalyst support member of the present invention was 1.3572 (g) and that of the prior art catalyst support member was 2.0414 (g), which was obtained by calculating the weight of the catalyst layer by Differences in the weight before and after the application of the slurry and the heat treatment have been measured. Then both samples were kept in an electric oven at 1000 ° C for a period of 10 minutes and then taken out therefrom and cooled to room temperature.

Then, the peeling test was conducted by immersing both samples in a water tank of an ultrasonic vibrator (180W, 42Hz) and holding them in the water tank using ultrasonic vibration. This peeling test was repeated 5 times and the peeling rate of the catalyst layer was calculated from the weight change before and after the peeling tests. As in 6 is shown, the peeling rate of the catalyst layer of the catalyst support member 1 of the present invention was 2.61% and that of the prior art metal catalyst support member was 6.71%. It can be shown that the catalyst layer of the catalyst carrier element 1 of the present invention can remarkably reduce the peeling test of the metallic catalyst layer in comparison with that of the prior art metal catalyst support member.

Since the metallic catalyst layer on rough surfaces of the catalyst support member 1 prepared from the fired sheet-like catalyst carriers P (Pa, Pb) prepared by the wet paper making method according to the present invention is supported, it is possible to have a catalyst device for exhaust gas purification, which has excellent durability against vibration and against heat and which can suppress the peeling during use and can easily recover the metallic catalyst after use. That is, since the catalyst support member 1 of the present invention is formed of film-like catalyst carriers P produced by the wet paper-making method, and therefore the surfaces of the catalyst carrier member 1 roughened by fibers, the catalyst layer, which on the surfaces of the catalyst carrier element 1 are applied to keep it safe for a long time.

In addition, because the catalyst support element 1 has been prepared by a step S3 of the paper-making film production of the sheet-like catalyst carrier P by flocs formed by adding flocculant into a slurry of a predetermined amount of water mixed with predetermined fibers and binders. be added; in addition, by a firing step S6 for firing the film-like catalyst support P, which has been obtained in the step S3 of the film production has been prepared; and also by a step S7 for applying the metallic catalyst to the surfaces of the catalyst carrier member 1 produced in the firing step S6, it is possible to have a catalyst device for exhaust gas purification which has excellent durability against vibration and heat, and which can suppress peeling off in use and metallic after use Catalyst can recover easily.

As the catalyst support element 1 Moreover, for the honeycomb structure, it is possible for the honeycomb structure to guide the exhaust gas flow through the inside of the honeycomb structure formed by adhering a corrugated foil-like catalyst carrier Pb to at least one surface of a flat foil-like catalyst carrier Pa and winding it up on a roll catalyst carrier member 1 let pass through and thus safely carry out the operation of the exhaust gas purification. In addition, since the firing temperature is within a range of 1450 to 1550 ° C according to the present invention, it is possible to perform a complete firing, wherein during the firing step S6, a melting of the catalyst carrier member 1 is avoided.

The present invention has been described with reference to the preferred embodiment. Upon reading and understanding the above detailed description, modifications and changes will be apparent to one of ordinary skill in the art. It is intended that the present invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof. For example, the noble metals to be supported in step S7 for applying the metallic catalyst may be catalyst metals other than platinum, rhodium and palladium. In addition, the sheet-like catalyst carrier P may be made of materials other than ceramic powder and alumina / silica fibers, and ceramic powders other than alumina may be used. In addition, the weight ratio of the alumina / silica fibers to the ceramic powder of the alumina contained in the catalyst support member 1 contained a different weight ratio than a range of 0.2 to 2.5.

APPLICABILITY IN INDUSTRY

The present invention can be applied to other types of exhaust purification apparatus than those for a vehicle as long as the apparatus is made of the sheet-like catalyst structure on the surfaces of which a metallic capacitor is supported by forming the catalyst layer after the sheet-like catalyst structure formed by the wet papermaking process has been produced,

LIST OF REFERENCE NUMBERS

1

Catalyst support element

2

tank

3

cylinder mold

4

tank

5

roll press

6

drying machine

7

rewinder

P

foil-like catalyst support

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2004-169111 A [0004]
• JP 08-299808 A [0004]
• JP 06-71185A [0004]

Claims (7)

Catalyst device for exhaust gas purification, comprising a catalyst support element ( 1 ) on which a metallic catalyst for exhaust gas purification is carried, characterized in that the catalyst support element ( 1 ) is molded from a sheet-like catalyst carrier (P) prepared by a wet paper making method, and that the metallic catalyst is carried as a catalyst layer on the surfaces of the sheet-like catalyst carrier (P) after the sheet-like catalyst carrier (P) has been fired The exhaust gas purification catalytic device according to claim 1, wherein the film-like catalyst carrier (P) contains ceramic powder and alumina / silica fibers. The exhaust gas purification catalytic device according to claim 1, wherein the ceramic powder contains alumina. A catalyst device for exhaust gas purification according to claim 3, wherein the weight ratio of the alumina / silica fibers to the ceramic powder of the alumina contained in the catalyst support member ( 1 ) is within a range of 0.2 to 2.5. A catalyst device for exhaust gas purification according to any one of claims 1 to 4, wherein the firing temperature is within a range of 1450 to 1550 ° C. A catalyst device for exhaust gas purification according to any one of claims 1 to 5, wherein the catalyst carrier element ( 1 ) is produced by a film-forming step (S3) to prepare the paper of the sheet-like catalyst carrier (P) of flakes by adding a flocculating agent into a slurry of a predetermined amount of water mixed with predetermined fibers and binders; and a firing step (S6) for firing the sheet-like catalyst carrier (P) obtained in the film-forming step (S3); and by a step of applying the metallic catalyst to the metal catalyst on the surfaces of the catalyst support member ( 1 ) which has been obtained in the firing step (S6). A catalyst device for exhaust gas purification according to any one of claims 1 to 6, wherein the catalyst carrier element ( 1 ) has a honeycomb structure formed by adhering a corrugated foil-like catalyst carrier (Pb) to at least one surface of a flat sheet-like catalyst carrier (Pa) and winding (Pa, Pb) on a roll.

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