JPS5811253B2 - Method for producing catalyst or carrier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a monolithic carrier or catalyst at low cost and with high activity.

Catalysts with through holes in the gas flow direction (hereinafter referred to as monolith catalysts) have extremely low pressure loss due to gas flow.
The height, V, and height can be set, and by selecting the diameter of the through-hole according to the dust content, the dust in the exhaust gas can pass through the through-hole without accumulating on the catalyst layer, making it suitable for processing dust-containing exhaust gas. It has the following characteristics.

The manufacturing method of this monolithic catalyst is classified into 1) a method of coating a ceramic substrate with a carrier and a catalyst material, and 2 a method of extruding the carrier and/or the catalytic material itself. The affinity with the catalytic material is weak, resulting in weak adhesion, and the amount of water absorbed by the ceramic substrate is low, resulting in a small amount of coating per coating operation.Therefore, coating operations must be repeated many times under strict process control. In the case of (2), the amount of carrier or catalyst material used is large, making the catalyst expensive and difficult to handle due to its weight. This has the disadvantage that certain limits must be imposed on the dimensions.

On the other hand, a monolith body made by making paper or board using only heat-resistant fibers, especially asbestos fibers, which are highly flexible and inexpensive, by corrugating or bonding flat plates is inexpensive. Moreover, while it has the advantage of having a small apparent specific gravity and is easy to handle in the catalytic process, this catalyst also has low cost performance when catalyzed by a coating method for the same reason as the ceramic base material mentioned above. It had the disadvantage of being low.

The present applicant previously filed a patent application No. 53 for an invention aimed at the above purpose.
-112558.

The gist is that ``a catalyst substance or catalyst precursor substance, a carrier substance or a carrier precursor substance,
A carrier material or a carrier precursor material is strained to obtain a flat or paper-like material, and then it is shaped to have a large number of through holes in the gas flow direction, or a catalyst layer that has a large number of through holes in the gas flow direction. A carrier or catalyst characterized in that it is formed into a shape that can be loaded so as to have the following characteristics.

As a result of further study, the present inventors discovered that
They have discovered a method for producing a carrier which has an activity several times superior to that of the catalyst or carrier according to No. 558, does not have the above-mentioned drawbacks, and is highly cost-effective.

That is, (a) between heat-resistant fibers such as beaten asbestos fibers, a carrier material such as titania or alumina, or a support material such as titanium hydroxide or alumina hydroxide, a framework material and/or a catalytic material such as vanadium pentoxide or iron oxide, or ammonium metavanadate, After 5 to 80% by weight of a catalyst precursor material such as iron hydroxide is added to the heat-resistant fibers to be made into paper to obtain a flat or paper-like material, (b) a carrier from which the flat or paper-like material is made into paper; coated with a substance or carrier precursor material and/or a catalyst material or catalyst precursor material, and the coating is further coated (i) with a large number of through holes in the gas flow direction or (11) loaded in a catalytic reaction device. (c) forming the flat or paper-like object into a monolithic structure having a large number of through holes in the gas flow direction; ) Molding into a shape having a large number of through holes in the gas flow direction by loading in a catalytic reaction device, and further converting the molded body into a paper-made carrier material or carrier precursor material and/or catalyst material or catalyst precursor material. A catalyst or carrier is produced by coating the catalyst or carrier.

The present invention will be explained in detail below.

The heat-resistant fiber that can be used in the present invention may be any one that can be beaten and has heat resistance (200° C. or higher), and may be either organic or inorganic.

Commercially available inorganic fibers include glass fiber, ceramic fiber, blue asbestos, chrysotile fiber, amosite fiber, rock wool, carbon fiber, titanate potash fiber, siliceous fiber, anthophyllite fiber, etc., and commercially available organic fibers include Teflon. Examples include fibers and the like.

Note that these selections are made taking into consideration usage humidity, economic efficiency, and the like.

For example, asbestos is suitable for use at temperatures below 500°C, and ceramic fibers are suitable for use at about 1000°C.

Further, the preferable fiber length is 1 to 20 mm, and the preferable fiber diameter is 0.1 to 30 μ.

The carrier material used during straining in the present invention is preferably in powder form, and the carrier precursor material is preferably in powder, sol, or gel form.

Compounds include chikunia, alumina, silica, and silica.
Known carrier materials such as alumina, magnesia, zirconia, and doria, and known carrier precursor materials such as titanium hydroxide, aluminum hydroxide, and magnesium hydroxide can be used.

The nature of the catalyst material used during straining in the present invention is preferably powdery, similar to the carrier material, and that of the catalyst precursor material is powdery,
Sol and gel forms are preferred.

The catalyst material may be selected appropriately depending on the catalytic reaction. For example, in the case of selective reduction and denitration reaction of NOx by NH3, Cub, Fe2O3, V2O5, WO3゜MoO
The straining is carried out using a No. 3 grade.

The content of the above-mentioned carrier material and/or catalyst material in the plate-like or paper-like material obtained by the method of the present invention is preferably 5 to 80% by weight based on the heat-resistant fibers such as asbestos to be strained.

This is because if the content is less than 5%, the effect of adding the carrier material, ie, the improvement of the catalytic activity or the supporting ability of the carrier, and the improvement of the adhesion strength between the carrier material, etc. and the plate or paper are insufficient. On the other hand, if it is more than 80%, the mechanical strength of the paper-like or flat plate-like product produced by papermaking etc. will be insufficient, and it will be very difficult to form the paper-like product into a monolith.

In addition, the particle size of the carrier material etc. to be strained is 0 from the viewpoint of yield.
．． 01-50μ is preferable.

Note that the term ``sneaking'' in the present invention refers to the operation of fixing a carrier substance or a carrier precursor and/or a dissolving medium or a catalyst precursor into the knitted beaten heat-resistant fibers. A carrier material or a carrier precursor material and/or a catalyst material or a catalyst precursor material, etc., and if necessary, a fixing agent such as NBR, SBR, polyamine, aluminum sulfate, a paper strength agent, pulp, etc. are used to achieve a slurry concentration of 0. After preparing a paper stock having a concentration of 5 to 10 wt%, paper is made using a known fourdrinier or short-mesh ring paper machine, or a beaten heat-resistant fiber and a carrier material or a carrier precursor material and/or a catalyst material or a catalyst precursor material are prepared. etc., and alumina sol, silica sol, etc. as required.
For example, a flat plate may be produced by forming a slurry containing a known binder such as titania sol into a thin layer and drying the slurry.

Prior to molding, the paper or plate-like article obtained by the above method is coated with a carrier material or carrier precursor material and/or a catalyst material or catalyst precursor material.

The coating is performed by a known method, for example, using a carrier material or a carrier precursor and/or a catalyst material or catalyst precursor, and if necessary, a binder such as titania sol, alumina sol, or silica sol, or a coating aid such as clay. This is accomplished by preparing a slurry, immersing the paper or plate-like material in the slurry, removing excess slurry, drying, and baking if necessary.

The paper-like article or flat plate-like article, preferably the paper-like article coated by the above method, is formed into a monolith body by a known corrugated board processing machine or by laminating after fluting with the same machine.

Further, the paper-like article or the flat plate-like article, preferably the flat article, coated by the above method is formed into a monolith body by mounting it in a basket using a spacer.

Further, the paper-like or plate-like material obtained by the above method may be formed into a monolith body by the above-mentioned method before being coated with the catalyst material, etc., and then coated with the catalyst material etc. by the above-mentioned method.

The catalyst obtained by the method of the present invention can be used for the treatment of dust-containing exhaust gas, for example, the removal of nitrogen oxides from NOx with NH3, and for the treatment of high-carbon exhaust gas, such as NOx and H, C, in automobile exhaust gas. It is suitable for processing.

The present invention will be specifically explained below using examples.

Example 1 250g of asbestos fiber (average fiber length 2mm)
After thorough beating in water, 500 g of anatase-type titanium oxide powder having an average particle size of 0.5 μm was added thereto and thoroughly mixed.

Furthermore, polymer cationic polyelectrolyte (Lu, fax 29
5) was added thereto, and the pH was adjusted to 5 by adding sulfuric acid.

In addition, 1 Nitzball 1571 (NBR) manufactured by Nippon Zeon
After adding 0I and fixing the titanium oxide powder into asbestos fibers, making paper using a hand-sheeting machine, it was dried to a paper thickness of Q, 3 mm.
A paper-like material having a basis weight of 290 g/m2 was obtained.

The obtained paper was molded using a corrugator, and one part was laminated and bonded manually using a silica sol adhesive, and further baked at 200°C for 3 hours to obtain a monolith body of 84 ml with a through hole having a diameter of 4 mm. Ta.

On the other hand, the slurry was prepared by adding 5 g of vanadium pentoxide powder, 45 g of anatase type titanium oxide, and 250 ml of water.
Add 5 glass beads to the stainless steel bead.
This was done by adding 0ml of the mixture and stirring for 1 hour.

86 ml of monolith bodies are immersed in this slurry, excess slurry is removed, and then dried.

By repeating this operation twice, the amount of coating is 4.2g.
It became.

The catalyst obtained in this Example 1 is referred to as Catalyst A.

Example 2 After 1.5 kg of asbestos fiber used in Example 1 was sufficiently beaten in 304 ml of water, 500 g of anatase type titanium oxide powder was added thereto and thoroughly mixed.

Furthermore, polymer cationic polyelectrolyte (Lufax295)
21g of was added, and the pH was adjusted to 5 by adding sulfuric acid.

In addition, 1 Nippon Zeon Nitzpol 1571 (NBR)
The titanium oxide powder was fixed in asbestos fibers, and after being made into paper using a hand-sheeting machine, it was dried to obtain a flat sheet with a paper thickness of 1 mm and a basis weight of 660 g/m2.

This flat plate-like object was placed in the basket shown in FIG.

(The volume of this basket is 84 m1, and the equivalent diameter of the through hole is 8 mm.

) The obtained monolith body was immersed in a slurry prepared in the same manner as in Example 1, excess slurry was removed, and then dried.

The same operation was repeated twice, and the coating amount was 4.8y.

The catalyst obtained in Example 2 is referred to as Catalyst B.

Reference Example-1 Commercially available asbestos paper (paper thickness 0.3 mm, basis weight 150 g/m2) was laminated in the same manner as in Example 1 to produce a monolith body 86 having the same through-hole diameter as in Example 1.
m1 was obtained.

This monolith body was immersed in a slurry prepared in the same manner as in Example 1, excess slurry was removed, and then dried.

Repeat the same operation 4 times to obtain almost the same amount as in Example 1 4.1
A coating of g was performed.

Note that when this coating was compared with the coating according to Example 1, there was a clear difference in adhesion strength.

The catalyst obtained in Reference Example 1 is referred to as Catalyst C.

Reference Example-2 After 1.5 kg of asbestos fiber used in Example 1 was thoroughly beaten in 301 water, anatase type Ti024 was added to it.
Add 50 g and 50 I of vanadium pentoxide powder and mix thoroughly.

Thereafter, a catalyst was obtained in the same manner as in Example 2.

Reference Example 3 A commercially available cordierite honeycomb (through-hole equivalent diameter: 4 mm) was immersed in a slurry prepared in the same manner as in Example 1, and after removing excess slurry, it was dried.

The same operation was repeated three times.

The amount of coating was 4.9g. The obtained catalyst is designated as catalyst E.

Example 3 84 ml of catalysts obtained from catalysts A, B, and C were loaded into a Pinox glass tube (with external heat insulation) having an inner diameter of 50 mm.
NN0200pp, NNO2NNO200pp10%,
A mixed gas of 12% CO2 and 1000pp residual SO2 was contacted at a space velocity of 10,000 Hr-1 (room temperature equivalent) to determine the NOx removal rate.

However, the NOx removal rate was calculated using the following formula.

The results are shown in Table 10 Example 4 Using the catalyst according to Example 1 and the catalyst according to Reference Example, coating film adhesion strength and coating film hardness tests were conducted in the following manner.0 Paint film adhesion strength Nichiban Co., Ltd. Company-made sellotape [L-Pack (LP-2)
4) J was adhered to a total of 5 occm2 of the catalyst coating film, the cellophane tape was peeled off, and the amount adhered to the cellophane tape was measured.

Coating film hardness test The hardness was measured by applying a load to the scratched part of a U-F scratch type film hardness tester manufactured by Uejima Manufacturing Co., Ltd. and measuring the hardness by applying the load that caused the scratch.

The results are shown in Table 2.

[Brief explanation of the drawing]

Figure 1 shows the basket that fixes the plate-shaped catalyst.

Claims (1)

[Claims] 1 (a) A carrier substance or a carrier precursor substance and/or a catalyst substance or a catalyst precursor substance is squeezed between beaten heat-resistant fibers in an amount of 5 to 80% by weight based on the heat-resistant fibers to form a flat plate or paper. (b) coating the plate-like or paper-like material with the strained carrier material or carrier precursor material and/or catalyst material or catalyst precursor material; or (i) shaping the plate-like or paper-like material to have a large number of through-holes in the gas flow direction by loading it in a catalytic reaction device; (i) molded into a shape having a large number of through holes in the gas flow direction; or (ii) molded into a shape having a large number of through holes in the gas flow direction by loading in a catalytic reaction device; 1. A method for producing a catalyst or carrier, which comprises coating with a strained carrier material or carrier precursor material and/or a catalyst material or catalyst precursor material.