JPH0780329A - Catalyst carrier - Google Patents

Abstract

PURPOSE:To sufficiently decompose ozone even when the ozone concn. is high and a large amt. of gas is introduced by using a porous body contg, a specified number of pores having a specified diameter and other pores having a specified diameter and with the total pore volume specified. CONSTITUTION:This catalyst carrier consists of a porous body contg. >=50vol.%, based on the total pore volume, of pores having >=0.1mum diameter and >=5vol.% of pores having >=5mum diameter measured by the method of mercury penetration and with the total pore volume controlled to >=0.4cc/g. Consequently, when a catalyst is deposited on such a porous body and the body is used as an ozone filter, a gas contg. ozone not only reacts with an active metal on the porous body surface but rapidly intrudes inside from the open part on the porous body surface, and the gas is brought into contact with the active metal and decomposed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a novel catalyst carrier, more specifically, for a device for decomposing ozone generated from a corona discharge part of an optical copying machine, a facsimile, a laser beam printer, a refrigerator, a toilet, etc. The present invention relates to a catalyst carrier suitable for an ozone filter used in a deodorizer that also uses ozone.

[0002]

2. Description of the Related Art Conventionally, a honeycomb type is used for a device for decomposing ozone generated from a corona discharge part of an optical copying machine, a facsimile machine, a laser beam printer, etc., and an ozone deodorizer used in refrigerators, toilets, etc. Activated carbon and ozone filters are used.

This ozone filter is usually a porous carrier on which an ozone decomposition catalyst is carried. As this porous carrier, for example, the pore volume is 0.5 cc / g or more and the specific surface area is 20 m ² / g. The above porous body (Japanese Patent Laid-Open No. 57-
160948), the total pore volume is 0.5 to 1.5c.
c / g, of which pore size is 1000 to 1000
A porous body having a volume of 0Å of 0.2 to 0.6 cc / g (Japanese Patent Laid-Open No. 62-61637) and a specific surface area of 100 to 350.
m ² / g, radius 40Å to 100Å and radius 10
A porous body having a clear peak each from 0Å to 500Å (Japanese Patent Laid-Open No. 1-349929), a porous body having a peak radius of 15 to 100Å and a pore radius of 500Å to 1 µm ( Japanese Patent Laid-Open No. 1-25422
No. 54), radius 40 to 200Å and radius 200 to 3
A porous body having a clear peak at 000 Å each (JP-A-2-15485), a total pore volume of 0.3 cc / g or more and a pore volume of 100 Å or more is the total pore volume. 60% or more of the porous material (Japanese Patent Application Laid-Open No. 2-7
No. 5341) has been proposed so far.

However, the amount of ozone discharged from the equipment, which is accelerated each year, is increasing, and the air volume is also increasing. Recently, the ozone filter using the conventional porous material as described above is sufficient. It is becoming impossible to achieve that purpose. That is, the conventional ozone filters have a drawback that the concentration of ozone to be treated must be lowered when the air volume is large, and the life is short if the ozone filter is used at a high concentration. This is because all the conventional ozone filters are mainly 0.
It is believed that this is due to the fact that the pore diameter is 1 μm or less.

[0005]

DISCLOSURE OF THE INVENTION The present invention overcomes the drawbacks of the conventional ozone filters, and can sufficiently exert the ozone decomposing effect even when the ozone concentration is high and the air volume is large. Moreover, the present invention has been made for the purpose of providing a catalyst carrier composed of a porous molded body that provides an ozone filter or the like that has a long life even at high temperatures.

[0006]

As a result of intensive studies to develop a catalyst carrier particularly suitable as an ozone filter, the present inventors have a specific pore distribution and a constant volume of all pores. By using the above porous body,
It has been found that the object can be achieved, and the present invention has been completed based on this finding.

That is, according to the present invention, in the pore distribution measured by mercury porosimetry, the pores having a diameter of 0.1 μm or more account for 50% or more of the total pore volume, and the pores having a diameter of 5 μm or more account for 5 of the total pore volume. % Of total pore volume is 0.4
A catalyst carrier composed of a porous body having a cc / g or more, preferably a catalyst carrier having at least 5 pore openings with a diameter of 0.05 mm or more per 1 mm ^{2 on} its surface when observed by a microscope. Is.

The material of the porous body that constitutes the catalyst carrier of the present invention can be arbitrarily selected from the materials that have been used as materials for ozone filters so far. Examples of such materials include alumina, silica, titania, zirconia, silica-alumina, silica-magnesia, alumina-magnesia, alumina-titania, silica-titania, alumina-zirconia, silica-zirconia, and zeolite.

In the present invention, the pore distribution of these materials measured by mercury porosimetry has a diameter of 0.
It is necessary to form a porous body having pores of 1 μm or more in 50% or more, preferably 70% or more of the total pore volume, and pores of 5 μm or more in diameter of 5% or more, preferably 10% or more of the total pore volume. Is.

To obtain such a pore distribution, the grain size of 0.
A granular material having a particle size of 5 μm or more, preferably 5 μm or more is mainly used, and a raw material containing 20% by weight or less of the granular material having a particle size of 0.1 μm or less is extruded and fired. Generally, in the case of extrusion molding, particles having a small particle size among the materials tend to gather near the surface.
If it exceeds 5% by weight, it collects near the surface and forms a smooth surface, so that the desired pore distribution cannot be obtained.

In addition to the above, a raw material mainly composed of granules having a particle size of 0.1 μm or less is used, and after extrusion molding, when heating or drying is rapidly applied, 0.1 μm or more, preferably 5 μm or more.
It is also possible to form a desired pore distribution by generating fine cracks of about 10 μm.

Further, in the present invention, it is necessary to use a porous body having a total pore volume of 0.4 cc / g or more. This requirement depends on, for example, the amount of the vaporizable substance present in the raw material. It can be achieved by adjustment and control of heating conditions during drying and firing.

Next, it is preferable that the porous body of the present invention has at least 5 pore openings with a diameter of 0.05 mm or more per 1 mm ^{2 on} its surface. When molding, the grain size in the raw material is 0.05
It is carried out by blending a vaporizable substance of mm or more. Examples of the vaporizable substance include organic substances such as cellulose, synthetic resins, naphthalene and camphor, and carbonaceous substances, inorganic substances such as boric acid and carbonates. These are usually blended in a proportion of 5 to 20% by weight based on the raw material for forming the porous body.

Further, fine particles are granulated with or without a binder to prepare shrinkable granules having a particle size of 0.05 mm or more, and the granules are molded into a predetermined shape and then heated and fired to give each granule. The desired porosity distribution and surface porosity openings may be formed by condensing and contracting the spores to generate porosity between the granules. As the binder in this case, natural substances such as water-soluble starch, alginic acid and gelatin, and modified substances such as carboxymethyl cellulose, methyl cellulose and ethyl cellulose, and synthetic substances such as polyvinyl alcohol, polyvinyl methyl ether and water-soluble polymers such as polyvinyl pyrrolidone Is used.

Generally, as the fine particles used for preparing the granules, a carrier having a specific surface area of 50 m ² / g or more is preferably used because a carrier having a larger specific surface area gives a carrier having better filter characteristics.

In order to produce the catalyst carrier of the present invention, for example, the above-mentioned required raw material components are mixed at a required ratio, an appropriate amount of water is added and kneaded, and then extrusion-molded into a required shape. The molded body thus obtained is then subjected to 100 to 300 ° C.
Dry at the temperature of. This drying is usually carried out under atmospheric pressure, but it can also be carried out under reduced pressure in order to promote pore formation. After drying, it is baked at a temperature of 500 to 1100 ° C. using an electric furnace or the like. This firing time is usually within the range of 1 to 10 hours.

In this way, a porous body containing pores having a diameter in the range of 0.01 to 10 μm in the range of 0.4 to 1.5 cc / g is obtained. The specific surface area of this porous body is preferably 50 m ² / g or more.

In the present invention, by providing the above-mentioned pore distribution and especially the surface pore openings, when a catalyst is supported on this porous body to form an ozone filter,
The ozone-containing gas not only reacts with the active metal present on the surface of the porous body, but also rapidly enters the internal pores through the pore openings on the surface of the porous body and is contacted with the active metal for decomposition. .

The thus obtained catalyst carrier of the present invention is formed in any shape such as a columnar shape, a prismatic shape, a tubular shape, a spherical shape or a cylindrical shape, and carries a catalytically active component according to the purpose of use. It can be a catalyst.

When the catalyst carrier of the present invention is used in an ozone filter, it is advantageous to have a honeycomb shape.

Examples of the catalytically active component which can be supported on the catalyst carrier of the present invention include catalytic metal components for hydrogenation such as molybdenum, tungsten, nickel, cobalt and copper, and calcinations such as platinum, palladium and rhodium. For example, a catalytic metal component for ozone, a catalytic metal component for ozone decomposition such as cobalt, nickel, molybdenum, tungsten, manganese, vanadium, zirconium, and silver can be used.

To support the catalyst metal component on the catalyst carrier of the present invention, for example, the catalyst carrier is impregnated with an aqueous solution in which a compound of these metals is dissolved, and then the temperature is 300 to 600 ° C.
The baking operation can be repeated several times until the required amount of catalytic metal component is adsorbed.

[0023]

EXAMPLES Next, the present invention will be described in more detail by way of examples.

Example 1 58 parts by weight of aluminum hydroxide (particle size 2 to 5 μm),
Silica A (particle size 1-4 μm, specific surface area 18 m ² / g) 1
9 parts by weight and silica B (particle diameter 0.01 to 0.05 μm,
7 parts by weight of specific surface area 100 m ² / g and boric acid (reagent 1
16 parts by weight) and 8 parts by weight of a methylcellulose-based binder were dry-mixed, and then 27 parts by weight of water and 8 parts by weight of glycerin as a plasticizer were added and kneaded by a batch kneader. Next, this kneaded material was extrusion-molded into a honeycomb shape, and this molded body was dried at 200 ° C. for 1 hour, and then
By firing for 1 hour at 00 ° C, the length is 31m
m, width 28 mm, length 12 mm, external dimensions 58.4%, hole diameter 1.49 mm, wall thickness 0.46 mm,
A honeycomb structured carrier having a pitch of 1.95 mm was manufactured.
The pore size distribution of this carrier measured by a mercury porosimeter is shown as graph I in FIG.

As can be seen from this, the total pore volume of this carrier is 0.57 cc / g, the ratio of the pores with a pore diameter of 0.1 μm or more to the total pore volume is 82%, and the total pores with a pore diameter of 5 μm or more is The ratio to the volume was 21%.

Further, microscopic photographs were taken at 5 places on the randomly selected surface of this carrier, and the number of pore openings having a diameter of 0.05 mm or more per 1 mm ² was read. The number was 2 to 5 Met.

Example 2 Example except that the amount of aluminum hydroxide was changed to 61 parts by weight, the amount of silica A was changed to 15 parts by weight, the amount of silica B was changed to 18 parts by weight, and the amount of boric acid was changed to 6 parts by weight. A honeycomb structured carrier was manufactured in the same manner as in 1. Figure 1 shows the pore size distribution of this product.
Is shown as graph II.

As can be seen from this, the total pore volume of this carrier is 0.51 cc / g, the ratio of the pores with a pore diameter of 0.1 μm or more to the total pore volume is 53%, and the total pores with a pore diameter of 5 μm or more is 53%. The ratio to the volume was 8%. Further, the number of pore openings on the surface obtained in the same manner as in Example 1 was 0 to 1.

Example 3 58 parts by weight of aluminum hydroxide (particle size 2 to 5 μm),
Silica A (particle size 1-4 μm, specific surface area 8 m ² / g) 19
By weight, 16 parts by weight of boric acid (first-grade reagent) and 8 parts by weight of a methylcellulose-based binder were dry mixed. Then 1
Silica B against 30 parts by weight of 0% by weight starch aqueous solution
(Particle size 0.01 to 0.05 μm, specific surface area 100 m ² /
g) A solution containing 7 parts by weight and 8 parts by weight of glycerin as a plasticizer was mixed with the above dry mixture and kneaded with a batch kneader. This kneaded product was extrusion-molded to manufacture the same honeycomb structured carrier as in Example 1. The pore size distribution of this product is shown as graph III in FIG.

As can be seen from the above, the total pore volume of this carrier is 0.51 cc / g, the ratio of the total pore volume of pores having a pore diameter of 0.1 μm or more is 87%, and the total pore diameter of pores having a pore diameter of 5 μm or more is 87%. The ratio to the volume was 10%.
Further, the number of pore openings on the surface determined in the same manner as in Example 1 was 15 to 25.

Comparative Example 1 The same aluminum hydroxide 62.5 used in Example 1
Parts by weight and the same silica B37.5 used in Example 1.
50 parts by weight of water was added to a mixture with parts by weight, and the mixture was kneaded and then extrusion-molded to manufacture the same honeycomb structured carrier as in Example 1. The pore size distribution of this product is shown as graph IV in FIG.

As can be seen, the total pore volume is 0.
It was 69 cc / g, and the ratio of pores having a pore diameter of 0.1 μm or more to the total pore volume was 11%, and the ratio of pores having a pore diameter of 5 μm or more to the total pore volume was 2%.

Comparative Example 2 Except that the amount of each component used was changed to 62.4 parts by weight of aluminum hydroxide, 18.8 parts by weight of silica A, 18.8 parts by weight of silica B, 5 parts by weight of boric acid and 46 parts by weight of water. In the same manner as in Example 1, a honeycomb structured carrier was manufactured. The pore size distribution of this product is shown as graph V in FIG.

As can be seen from the above, the total pore volume of this carrier is 0.73 cc / g, the ratio of the pores with a pore diameter of 0.1 μm or more to the total pore volume is 51%, and the total pores with a pore diameter of 5 μm or more is 51%. The ratio to the volume was 2%.

Reference Example 1 Each of the honeycomb structured carriers obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was impregnated with an aqueous solution of 18% by weight of cobalt acetate and then baked at 400 ° C. for 30 minutes three times. Cobalt oxide equivalent 50 by repeating
Ozone filters were prepared containing ~ 200 mg / g carrier. These specific surface areas are shown in Table 1.

Next, with respect to the filters using the carriers of Examples 1 and 2 and Comparative Examples 1 and 2, the ozone resolution was measured under the conditions of a temperature of -10 ° C, an ozone concentration of 100 ppm at the inlet, and a space velocity of 17,000 hr ^-1. , The results are shown in Table 1.
Shown in.

[0037]

[Table 1]

As is clear from this table, the ozone filter using the carrier of the present invention shows a markedly smaller decrease in performance over time than those using the other carriers.

Next, with respect to the ozone filters using the carriers obtained in Examples 1 and 3, the ozone resolution was measured under the conditions of a temperature of 25 ° C., an inlet ozone concentration of 100 ppm and a space velocity of 58000 hr ⁻¹ . The results are shown in Table 2.

[0040]

[Table 2]

As is clear from this table, the carrier using at least 5 pore openings with a diameter of 0.05 mm or more per 1 mm ² on the surface has a higher ozone decomposition rate than the carrier having less than 5 carriers. Indicates.

[0042]

The catalyst using the carrier of the present invention exhibits higher catalytic activity and activity durability than catalysts using other carriers. Since this effect is particularly remarkable when used as an ozone filter having a honeycomb structure, it is suitable for an ozone filter.

[Brief description of drawings]

FIG. 1 is a graph showing the pore size distribution of a honeycomb structured carrier obtained in an example of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tokuyuki Yasuda 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDC Corporation (72) Inventor Naoki Yago 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDC Within the corporation

Claims (2)

[Claims] 1. In the pore distribution measured by mercury porosimetry, pores having a diameter of 0.1 μm or more are defined as 50 of the total pore volume.
%, And 5% or more of the total pore volume of pores having a diameter of 5 μm or more, and the total pore volume is 0.4 cc / g or more. 2. The surface of the porous body has a diameter of 0.05 m.
The catalyst carrier according to claim 1, which has at least 5 pore openings of m or more per 1 mm ² .