JPH10216529A - Production of inorganic fiber catalytic base material and device for producing the base material and production of plate-like catalyst using inorganic fiber catalytic base material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an inorganic fiber catalytic base material which retainss a strength equal to or more than a conventional catalyst and can have its thickens reduced further. SOLUTION: An inorganic fiber woven cloth 1 is fed by each specified length to an impregnation tank 4 by a woven cloth feeder machine 2, then is impregnated with a reinforcing liquid 3 containing an inorganic binder using an impregnating machine 4, and an excess reinforcing liquid is removed with the held of a liquid draining roller 5. Further, a woven cloth impregnated with the reinforcing liquid thus obtained is supplied, in a tensionless state, between a pair of thickness-limiting rollers 7 heated at a specified temperature, while a space between the rollers 7 or a pressure between the rollers 7 is kept at a specified value. The inorganic fiber woven cloth is thinned and, at the same time, has its strength increased by causing the woven cloth to pass between the thickness limiting rollers 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for producing an inorganic fiber catalyst substrate and a method for producing a plate-shaped catalyst using the inorganic fiber catalyst substrate. The thickness can be reduced to reduce the pressure loss of the gas to be treated in a device equipped with a catalyst, and the number of catalysts that can be mounted in a device of the same volume can be increased to improve the processing capacity. The present invention relates to a method and an apparatus for producing an inorganic fiber catalyst base material, and a method for producing a plate catalyst using the inorganic fiber catalyst base material.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional method and apparatus for producing a substrate for a catalyst using an inorganic fiber woven fabric. In FIG. 3, the inorganic fiber woven fabric 1 wound around the shaft of the woven fabric feeder 2 is shown.
Is introduced into the impregnation tank 4 via the guide rollers 13 and 14, where it is immersed in the strengthening liquid 3 containing an inorganic binder (for example, silica, titania, alumina, etc.), Is removed, further dried by a hot-air dryer 9 via a tensioner 6, and wound up by a winder 8. By performing such treatment, the inorganic fiber woven fabric becomes a belt-shaped catalyst substrate having desired tensile strength, bending strength, and rigidity.

As shown in FIG. 7, a plate-shaped catalyst exposed to a high-temperature gas to be treated is prepared by preliminarily placing a belt-shaped catalyst base material 15 obtained by the above-described method between a pair of application rollers 21 and 22. It is supplied together with the kneaded paste-form catalyst composition 16 to form the catalyst composition 16 on the substrate 15.
It is known that a catalyst-coated body 17 is applied to the resultant and then dried and fired to obtain a plate-shaped catalyst. Here, reference numeral 23 denotes a receiving stand, and 24 denotes an application assisting paper.

[0004]

As shown in FIG. 4, a plate-like catalyst has a structurally large bending strength in a direction parallel to a hill portion serving as a spacer when laminating the catalyst.
In the direction perpendicular to the peak, the strength is determined by the bending strength of the catalyst itself, so that a sufficient bending strength of the plate-shaped catalyst itself is required.
In a plate-like catalyst, the bending strength in a certain direction depends on the tensile strength of a fiber parallel to that direction. Therefore, the woven fabric is pulled in a certain direction like the draining roller 5 and the tensioner 6 in FIG. 3, and the fibers are brought into close contact by pulling the fiber bundle 12 in FIG. 5, and inorganic binding such as silica or titania sol or slurry is performed. It has been practiced to reinforce fibers in a certain direction by making them sufficiently bonded to each other with an agent, and to improve the bending strength of the plate catalyst by improving the tensile strength of the fibers.

In recent years, by reducing the thickness of the plate catalyst, for example, in the case of a denitration catalyst for exhaust gas treatment for removing nitrogen oxides in exhaust gas, the denitration activity proportional to the reaction area is maintained, and the amount of catalyst is reduced. Research has been conducted to reduce the SO ₂ oxidation rate proportional to the fiber bundle. However, in the conventional woven fabric reinforcing method shown in FIG. 3, a fiber bundle without tension (the fiber bundle 12 ′ in FIG. 5) is used. It has been found that since the inorganic binder remains as a solid substance in the space between the woven fabrics, the woven fabric as a whole becomes thicker than before reinforcement. Therefore, when thinning the catalyst, in order to make the fiber bundle itself thinner than the woven fabric used for the conventional catalyst, there is no other way but to reduce the number of fibers constituting the fiber bundle or use thinner fibers. This has been a cause of lowering the strength of the base material and thus the strength of the catalyst.

An object of the present invention is to solve the above-mentioned problems of the prior art, to maintain a strength equal to or higher than that of a conventional catalyst, and to further reduce the thickness of the catalyst. Another object of the present invention is to provide a method for producing a plate catalyst using an inorganic fiber catalyst substrate.

[0007]

The invention claimed in the present application to achieve the above object is as follows. (1) a step of feeding a predetermined amount of an inorganic fiber woven fabric to an impregnation tank, a step of impregnating the sent woven cloth with a reinforcing liquid containing an inorganic binder in the impregnation tank, and a pair of heated rollers A step of passing the reinforcing liquid-impregnated woven fabric between the rollers to obtain a base material having a predetermined thickness while maintaining the interval between the rollers or the pressure between the rollers at a predetermined value. The method of manufacturing the material.

(2) The method according to (1), further comprising a step of drying a surface of the woven fabric impregnated with the reinforcing liquid before supplying the woven cloth impregnated with the reinforcing liquid between the heating rollers. A method for producing a fiber catalyst substrate. (3) a woven cloth feeder that sends the inorganic fiber woven cloth to the impregnation tank;
An impregnating tank for receiving the sent-out woven fabric and impregnating it with a reinforcing liquid containing a binder, a draining means for removing excess reinforcing liquid in the woven cloth impregnated with the reinforcing liquid; A heating and pressurizing means for heating and pressurizing the inorganic fiber woven fabric at a predetermined interval or at a predetermined pressure.

(4) In (3), the heating / pressing means is a pair of heated pressure rollers, and the surfaces of the pressure rollers are coated with a water-repellent and heat-resistant resin. An apparatus for producing an inorganic fiber catalyst substrate. (5) A predetermined amount of the inorganic fiber woven fabric is sent out to the impregnation tank by the woven fabric sending means, and the sent woven fabric is impregnated with a reinforcing liquid containing an inorganic binder, and the distance between the heated pair of rollers or between the rollers is adjusted. While maintaining the pressure at a predetermined value, the reinforcing liquid-impregnated woven fabric is supplied between the rollers in a state where the tension is removed, and is passed between the rollers to form an inorganic fiber catalyst base material having a predetermined thickness. A method for producing a plate-shaped catalyst using an inorganic fiber catalyst substrate, wherein a paste-like catalyst material is applied to one or a plurality of catalyst substrates, dried and calcined.

In the present invention, an inorganic fiber woven fabric is impregnated with a reinforcing liquid containing an inorganic binder, sufficiently drained, and then passed through a gap between a pair of heated rollers to prepare an inorganic fiber catalyst base material. . Here, by keeping the interval between the rollers or applying a constant pressure between the rollers,
Limit the thickness of the inorganic fiber woven fabric that passes. It is also important to reduce the tension applied to the woven fabric before passing through the thickness limiting roller as much as possible, so that the fiber bundle constituting the woven fabric can be easily deformed by the roller. It is also important to heat, whereby moisture in the woven fabric evaporates, and the shape of the woven fabric is fixed by the inorganic binder. By superimposition of these effects, it is possible to obtain a catalyst base material having a tensile strength equivalent to that of the conventional base material and being thinner than the conventional base material.

In the present invention, if the surface of the inorganic fiber woven fabric before passing through the rollers is dried by the dryer, the rollers are less likely to become dirty. Further, even if the roller surface is coated with a heat-resistant and water-repellent fluorine-based or silicon-based resin, the roller surface is hardly stained. By rolling and applying the paste-like catalyst powder to the base material thus produced, a catalyst having a thickness smaller than that of a conventional catalyst and having the same or higher bending strength can be obtained.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The contents of the present invention will be described in more detail with reference to specific examples. The catalyst raw materials and catalyst bases described in this example do not limit the present invention. Further, in this embodiment, the catalyst composition and structure are described according to the use of the denitration catalyst. However, the present invention is not limited to this use and structure, and may be used for, for example, an exhaust gas oxidation catalyst or a combustion catalyst.

Here, the structure other than the described pressure roller may be any structure as long as it performs the same function. Example 1 An apparatus for producing an inorganic fiber catalyst substrate used in this example is shown in FIG.
As shown in the figure, the feeder 2 of the inorganic fiber woven fabric 1 and the woven fabric 1
Impregnating tank 4 for impregnating reinforcing liquid 3 containing silica sol, a pair of sponge draining rollers 5 for removing excess reinforcing liquid from woven cloth 1 impregnated with reinforcing liquid 3, and drained cloth 1 comprises a tensioner 6 for applying a minimum tension that does not bend, a pair of heated thickness limiting rollers 7 for thermoforming the woven fabric 1, and a winder 8 for the reinforced woven fabric 1. In the present embodiment, a silica-alumina glass woven fabric (fiber diameter: 6 μm, fiber bundle thickness: 0.4 mm, fiber bundle interval: 2 mm) is used as the inorganic fiber woven fabric 1, and silica sol 10 wt.
%, Polyvinyl alcohol 1wt%, titania 50wt
%, Each using a mixture of which the water content has been adjusted,
The catalyst substrate is obtained by impregnating the inorganic fiber woven fabric 1 with the reinforcing liquid 3 while fixing the surface temperature of the thickness limiting roller 7 to 150 ° C. and the gap interval to 0.3 mm in the above-mentioned catalyst base material manufacturing apparatus. Was. Example 2 Drying the surface of the drained woven fabric 1 makes it difficult for the surface of the thickness-limiting roller 7 to become dirty during heat molding. Therefore, hot air drying is performed upstream of the thickness-limiting roller 7 as shown in FIG. A catalyst base material was obtained in the same manner as in the above example, except that a catalyst base material manufacturing apparatus equipped with a machine 9 was used. Example 3 In the same manner as in Example 1 except that a catalyst substrate manufacturing apparatus in which the surface of the thickness limiting roller 7 was coated with a 0.05 mm fluororesin so as to prevent the surface of the thickness limiting roller 7 from becoming dirty was used. A catalyst substrate was obtained. COMPARATIVE EXAMPLE 1 Using the apparatus shown in FIG. One tension was applied to obtain a catalyst substrate.

In order to confirm the effects of the above embodiment, a titanium oxide powder (hereinafter, titania powder, specific surface area of about 100 m) was used.
² / g) and vanadyl sulfate were weighed so as to have a weight ratio of 100: 12, water of 60% by weight was added to the titanium oxide, and the mixture was kneaded with a kneader for 30 minutes. Silica alumina fiber and molybdenum oxide were simultaneously added at a ratio of 15 and 21% by weight, and the catalyst paste kneaded for further 30 minutes was applied to the catalyst base materials prepared in Examples 1 to 3 and Comparative Example 1,
After drying, the plate catalyst was calcined at 500 ° C. for 2 hours to obtain a plate catalyst, and the obtained plate catalyst was compared in bending strength and plate thickness. The application of the catalyst paste was carried out by sandwiching the paste between two base materials, rolling with a roller, and spreading and pressing the catalyst paste on the base material.

The test conditions of the bending test are shown in Table 1, and the results are shown in Table 2. In addition, when the catalyst paste was applied to the catalyst base material manufactured in Comparative Example 1 under the same conditions as in the example, the upper and lower base materials were separated, so that Comparative Example 1 was the thinnest sample that could be applied without separating the base material. The test results were used.

[0016]

[Table 1]

[0017]

[Table 2] In Table 2, the thickness of the catalyst substrate and the plate thickness of the plate catalyst are smaller in Examples 1 to 3 than in Comparative Example 1,
It can be seen that the flatness of the inorganic fiber catalyst substrate according to the present invention reduces the thickness after the application of the catalyst. In addition, it can be seen that the bending strengths of Examples 1 to 3 are significantly improved in the bending test as compared with Comparative Example 1.

That is, in Comparative Example 1 using the apparatus of FIG. 3, after impregnating the reinforcing liquid 3 into the inorganic fiber woven cloth 1, draining the liquid and heating it with the hot air drier 9, the woven cloth is Thus, it is considered that only the fiber bundle 12 in the feed direction is pulled to have a circular cross section, and the fiber bundle 12 'in the other direction is thickened by an excessive reinforcing liquid. On the other hand, in Examples 1 to 3 using the apparatus of FIG. 1 or the improved apparatus thereof, when passing between the pair of heated rollers 7, almost no tension is applied to the fiber upstream of the roller 7. The fiber bundles 12 and 12 'in the directions are also formed into flat plates by the rollers 7 as shown in FIG. Therefore, this shape is maintained even if the substrate is pulled with a constant tension when winding the substrate. Since the fibers are pressurized, the fibers are in close contact with each other as in the conventional method. Therefore, the fiber bundles produced in Examples 1 to 3 are thinner in all directions than the fiber bundles of the conventional method.

[0019]

According to the present invention, it is possible to reduce the thickness of the inorganic fiber catalyst substrate while maintaining the same or higher strength as that of the conventional one, so that the thickness of the plate catalyst itself can be reduced. Low pressure loss can be achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an apparatus for producing an inorganic fiber catalyst base material according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram of an apparatus for manufacturing an inorganic fiber catalyst base material according to another embodiment of the present invention.

FIG. 3 is an explanatory view of a conventional inorganic fiber catalyst base material manufacturing apparatus.

FIG. 4 is an explanatory view of a plate catalyst.

FIG. 5 is an explanatory view showing the shape of a fiber bundle of a conventional inorganic fiber catalyst substrate.

FIG. 6 is an explanatory diagram showing a shape of a fiber bundle when passing through a pressure roller of the present invention.

FIG. 7 is a diagram illustrating a state in which a catalyst paste is applied to an inorganic fiber woven fabric base material.

[Explanation of symbols]

1: inorganic fiber woven fabric, 2: woven fabric feeder, 3: reinforcing liquid,
4: impregnation tank, 5: draining roller, 6: tensioner, 7:
Thickness limiting roller, 8: winder, 9: hot air dryer, 1
0: plate-shaped catalyst, 11: plate-shaped catalyst peak, 12, 12 ': fiber bundle, 13, 14: guide roller, 15: base material, 16:
Paste catalyst composition, 17 ... catalyst coated body, 21, 22
... Coating roller, 23 ... Coating table, 24 ... Coating auxiliary paper.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI D06C 29/00 D06C 29/00 A

Claims (5)

[Claims] 1. A step of feeding a predetermined amount of an inorganic fiber woven fabric to an impregnation tank, a step of impregnating the sent-out woven cloth with a reinforcing liquid containing an inorganic binder in the impregnation tank, A step of passing the reinforcing liquid impregnated woven fabric between the rollers to obtain a base material having a predetermined thickness while maintaining the distance between the rollers or the pressure between the rollers at a predetermined value. A method for producing a catalyst substrate. 2. The inorganic fiber according to claim 1, further comprising a step of drying the surface of the woven fabric impregnated with the reinforcing liquid before supplying the woven cloth impregnated with the reinforcing liquid between the heating rollers. A method for producing a catalyst substrate. 3. A woven fabric feeder for feeding an inorganic fiber woven fabric to an impregnation bath, an impregnation bath for receiving the fed woven fabric and impregnating the woven fabric with a reinforcement liquid containing a binder, and an impregnation liquid impregnated with the reinforcement liquid. It is provided with a draining means for removing excess reinforcing liquid in the woven fabric, and a heating and pressurizing means for applying pressure while heating the drained inorganic fiber woven fabric at a predetermined interval or a predetermined pressure. Characteristic equipment for manufacturing inorganic fiber catalyst base material. 4. The method according to claim 3, wherein the heating / pressurizing means is a pair of heated pressure rollers, and the surface of the pressure roller is coated with a resin having water repellency and heat resistance. Characteristic equipment for manufacturing inorganic fiber catalyst base material. 5. A method for feeding a predetermined amount of an inorganic fiber woven fabric to an impregnation tank by a woven fabric sending means, impregnating the sent woven fabric with a reinforcing liquid containing an inorganic binder, and heating the space between a pair of heated rollers. While maintaining the pressure between the rollers at a predetermined value, the reinforcing liquid-impregnated woven fabric is supplied between the rollers in a state where the tension is removed, and is passed through the rollers to form an inorganic fiber catalyst substrate having a predetermined thickness. A method for producing a plate-shaped catalyst using an inorganic fiber catalyst substrate, wherein a paste-like catalyst material is applied to one or a plurality of inorganic fiber catalyst substrates, dried and calcined.