JPS58104638A - Catalyst deposited on heat resistant nonwoven fabric - Google Patents

Abstract

PURPOSE:To obtain a catalyst having heat resistance and good in the utilization efficiency of a catalytic metal, by a method wherein a nonwoven fabric comprising a heat resistant fiber based on silica or alumina is used as a carrier and a catalytic coating is formed on the surface thereof. CONSTITUTION:As a catalyst for treating various gases. a catalytic metal is adhered on the surface of a carrier constituted of a nonwoven fabric comprising a heat resistant fiber based on silica or alumina to form a catalytic coating. Because thus obtained catalyst has strength or elasticity and the density thereof can be freely selected, it is good in capacity and the catalytic metal is used effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a catalyst using refractory fiber as a carrier, and more specifically, the present invention relates to a catalyst using refractory fiber as a carrier. The present inventors have already disclosed in Japanese Patent Publication No. 55-58264 [
A method for forming a catalyst metal in the form of a uniform film on the surface of glass fiber containing 90% or more of silica was announced.
However, in the case of general textiles, one thread is made up of 2,000 to 10,000 glass filaments with a diameter of 9 micrometers, but the glass fiber structure using this method is actually When used for various gas treatments, when the gas flow rate is high and the SV value (catalyst space velocity) is set to 100.00 DH-1, the contact time between the thread and the gas is approximately o, o o s seconds. According to experiments, in this case, the surface area through which the processing gas permeates into the yarn and makes effective contact with it remains at 12 to 20 percent of the total surface area.

Therefore, the remaining fibers became almost ineffective catalysts.

In order to improve these drawbacks, the present invention discontinues the conventional textile method, that is, forming heat-resistant fibers into yarn-1 cloth, sheets, net-like materials, etc., and instead uses cotton-like fibers, that is, heat-resistant fiber filaments (
Monofilament) II: All fibers are made independent and condensed (5 tran
) The contact points between the filaments are hardened with a heat-resistant adhesive to prevent the filaments from dispersing (or scattering). It is made up of a so-called nonwoven fabric of heat-resistant fibers.

That is, the present invention relates to a catalyst in which a catalytic metal is adhered to the surface of a nonwoven fabric made of heat-resistant fibers containing silica or alumina as a main component.

The specific shape of the nonwoven fabric used in the present invention is similar to that of the commercially available F fabric, but the commercially available R fabric has an organic fiber (
Polyester, cellulose polyamide, etc.)
In addition, non-heat resistant glass fiber is used as an organic binder (adhesive).
Since they are individually molded, high heat resistance cannot be expected. In contrast, the catalyst carrier used in the present invention must be able to withstand high temperatures of at least 870i. Therefore, 9 has high heat resistance as a nonwoven fabric raw material.
Glass fiber containing 0% or more silica, or 5oq
A heat-resistant fiber containing an alumina content of 6 or more is used, and the binder necessary for molding this fiber also has a heat resistance of 870'C or more. /- is used.

The strength or elasticity of nonwoven fabrics is determined by the fact that the contact points between the single fibers are bonded, so when compression or tension is applied, the stress is not applied to the entire surface of the woven fabric through the bonded areas, so the strength increases. It is possible to retain it.

The non-woven carrier of heat-resistant fibers has a freely selected density;
The unit weight of the fiber is determined by the required effective surface area, and the shape (volume, thickness, and density) is determined by the allowable value of pressure loss due to flow rate. The performance efficiency is at least 5 to 83 times higher per unit weight than a woven fabric carrier, and it is possible to significantly reduce pressure loss due to wind speed. Of course, the volume increases in proportion to this because it swells like a cloth or felt, and the thickness also increases.

There are no particular restrictions on the catalyst wire mesh attached to the surface of the nonwoven fabric.
Just select it appropriately depending on the reaction in which the catalyst will be used□!
: However, usually one or more transition metals from group 4 a to group 7 a, or metals from other groups are added to these, and are used to produce oil combustion exhaust gas, various paint drying exhaust gas, boiler exhaust gas, internal combustion. Specific examples include catalysts for purifying engine exhaust gas, etc., and catalysts for deodorizing human waste, sewage, garbage plants, etc.

The method of attaching the catalyst metal in a uniform film to the surface of the nonwoven fibers is basically the method previously published by the present inventors in Japanese Patent Publication No. 51-21629, that is, applying an alcohol ester solution of a metal acid to the fibers. This is heated to gel, and then baked to give a
A method of forming a catalytic metal film .about.0.4 microns thick can be employed.

Example 1 ゞ□□ Using 120 kg of heat-resistant glass fiber with a fiber diameter of 9 microns and a silica content (5 in2) of 90 percent or more and 10 kg of a heat-resistant adhesive mainly composed of aluminum sol (containing 10% A12os), the thickness was A 118 m' (1 m x 118 m) nonwoven fabric of o,, o2s- was produced.The total volume of this nonwoven fabric was 2.95 m3, and the apparent specific gravity was 0.044.

Using 120 parts (weight ratio) of a silica fiber non-woven fabric, 20 parts of an aqueous solution of 20 weight percent chromic anhydride,
Catalyst solution 6 prepared from 20 parts of an aqueous solution of 25 weight percent magnesium acetate and 20 parts of propylene glycol
After spraying (spraying, coating) 0 parts to uniformly adhere the catalyst solution to the surface of each fiber, the first heat treatment was performed at 250°C for 2 hours (drying) and the second time at 600°C for 2 hours. , after cooling, 0.01% by weight aqueous palladium chloride solution 60
A portion was sprayed and heat treated in the same manner as last time.

This silica fiber nonwoven catalyst has a low pressure loss of 1.4 water columns when the wind speed is 1 m/sec, and has extremely low gas resistance. For comparison, we used 10 sheets (thickness 10＠＠) of conventional glass fiber woven cloth (screen sheets with a thickness of 1 mm and a mesh equivalent to ＼4 mesh) stacked together, and When the pressure drop was measured, it was found to be 65 ffiII+ water columns.

As shown in the attached drawing, one sheet of this catalyst nonwoven fabric N (thickness 2.5 mm, length 15 mm, width 25 mm) was installed on the top of a reflective oil stove S, and gas analysis before and after the catalyst nonwoven fabric was performed. Hydrocarbons before treatment (hexane equivalent) 75
ppm, - 22 ppm of dispersed carbon, which after treatment is reduced to 4.0 ppm of hydrocarbons, - 1.2 ppm of carbon oxides,
The purification rates were 94.5 and 94.6, respectively.

Example 2 Fiber diameter 9-12 microns, alumina content (At203) 8
Using 60 kilograms of heat-resistant alumina fiber containing 0% or more and 6 kilograms of heat-resistant adhesive mainly composed of alumina sol (containing A12"3 10 clp), a thickness of 0.025
A nonwoven fabric measuring 64 m2 (1 m x 64 m) was manufactured. The total volume of this nonwoven fabric was 1.61 tn3, and the apparent specific gravity was 0.041.

60 parts (by weight) of this alumina fiber nonwoven fabric was sprayed with 30 parts each of the catalyst solution prepared by the blending method of Example 1 and the palladium chloride aqueous solution and heat treated in the same manner as in Example 1.

The pressure loss of the nonwoven catalyst made of this alumina fiber is 1 per second at the wind speed.
m, the water column is 1.1 dew, and the gas resistance is extremely low.

This non-woven catalyst, thickness 2.5 cm, length 15111W
I, length 75 crn was applied to the exhaust gas purification muffler of a small diesel engine (250 horsepower), and before treatment;
Hydrocarbon, 251 ppm, -carbon oxide, 16021)p
m % after treatment; hydrocarbon, 15 ppm, - carbon oxide,
At 24 ppm, purification rates of 94.0% and 9a5% were obtained, respectively.

[Brief explanation of the drawing]

The attached drawings are diagrams showing examples of tests carried out to see the effects of the catalyst of the present invention. Application No. 201534 2°2”0 No. 2 Heat Resistance - Non-woven Catalyst 3, Relationship with the Amended Person Case Patent Applicant 1, i Location 2-5-1 Marunouchi, Chiyoda-ku, Tokyo Representative Yano - 4 , Sub-Agent I1 Address: 24-11-5 Toranomon-chome, Minato-ku, Tokyo
, Date of amendment order Voluntary amendment 6 Number of inventions to be increased by amendment ``r≧\Z Detailed explanation of invention column 8 of specification subject to amendment Contents of amendment (1) Page 4, line 8 of specification The statement "15 to 83 times the amount of

Claims (1)

[Claims] Silica Manen is a heat-resistant non-woven catalyst made by adhering catalytic metal to the surface of a non-woven fabric made of heat-resistant fibers whose main component is alumina.