JP2003093881A - Catalyst for removing nitrogen oxide and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a catalyst for removing nitrogen oxides, useful as an industrial catalyst with an excellent durability, in which a NOx removal rate is higher than those of the conventionally proposed catalysts for removing nitrogen oxides and a conversion rate to SO3 is low when ammonia is added to exhaust gas containing NOx, particularly simultaneously containing NOx and SOx and a reaction is catalytically carried out; and a manufacturing method therefor. SOLUTION: The catalyst for removing nitrogen oxides and the manufacturing method therefor are provided. The catalyst contains (1) a composite oxide (component A) obtained from a composite hydroxide ((a) component) slurry obtained by a method that a composite hydroxide (y component) slurry is obtained by adding a basic aqueous solution to a mixed aqueous solution of a soluble titanium compound, a soluble silicon compound and/or silica sol or a mixed aqueous solution of a soluble titanium compound, a soluble tungsten compound, a soluble silicon compound and/or silica sol and neutralizing it and after meta-titanic acid, a soluble silicon compound and/or silica sol are added to the composite hydroxide slurry, a basic aqueous solution is added thereto; (2) and at least one metal oxide (B component) selected from the group consisting of vanadium, molybdenum and tungsten.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst for removing nitrogen oxides and a method for producing the same, and more specifically, it discharges from heavy oil, coal-fired boilers, thermal power plants, iron mills, and other combustion furnaces The present invention relates to a catalyst for removing nitrogen oxides (hereinafter abbreviated as NOx) contained in exhaust gas and a method for producing the same.

[0002]

2. Description of the Related Art As a denitration catalyst for removing NOx in exhaust gas by using a reducing agent such as ammonia, a honeycomb-shaped catalyst in which an active component such as tungsten oxide or vanadium oxide is supported on a titanium oxide carrier is generally used. Is being used for. Since a denitration catalyst used industrially needs to deal with dust and sulfur compounds (hereinafter abbreviated as SOx) contained in exhaust gas, it is not only high in denitrification activity but also SO Ability to oxidize to ₃ (S
Various performances such as low O ₃ conversion) are required.

Generally, most of SOx contained in the exhaust gas is SO ₂ , but a part of this SO ₂ is oxidized on the denitration catalyst to become SO ₃ , and this SO ₃ is used as a reducing agent, NH ₃ Combines with the unreacted component of to produce acidic ammonium sulfate,
In order to cause blockage of devices such as heat exchangers in the wake, S
There is a problem that O ₃ itself causes corrosion of the device. Therefore, a denitration catalyst with a low conversion rate to SO ₃ has been desired.

Regarding the above-mentioned catalyst in which the conversion rate to SO ₃ is suppressed, Japanese Patent Publication No. 4-17091 discloses a ternary oxide of titanium, tungsten, and silicon, which is then formed, and then the vanadium compound is added to the oxide. There has been proposed a method for preparing a denitration catalyst, which is characterized by adding

Further, Japanese Patent No. 2825343 discloses that
In a method for producing a catalyst for catalytically reducing nitrogen oxides by catalytically reacting with ammonia, a soluble titanium compound and a soluble silicon compound and / or silica sol are used as starting materials, and the materials are treated with ammonia in an aqueous medium. The coprecipitate is neutralized to obtain a coprecipitate, and the coprecipitate slurry is aged in a pH range of 8.5 or more for 20 hours or more, washed, dried, and then fired to obtain titanium and silicon. The binary composite oxide consisting of is used as a catalyst (a) component, vanadium oxide is used as a catalyst (b) component, and tungsten oxide is used as a catalyst (ha) component. 82 to 97% by weight, component (B) in the range of 0.3 to 3% by weight and component (C) in the range of 3 to 15% by weight, and the composition of component (A) is titanium 7 in atomic percentage. 90%, the production method of the nitrogen oxide removing catalyst, characterized by comprising been adjusted to a range of 30 to 10% silicon has been proposed. However, in the production method of the present invention, when a catalyst having a complicated shape such as a honeycomb shape is formed, since the binary composite oxide has a simple particle size distribution, the plasticity is low and the interparticle bonding force is weak, There was a problem of poor moldability. Further, it is necessary to use a large amount of a molding aid or clay in order to improve the moldability and the strength of the molded body, which causes a problem that the catalytic performance is lowered.

[0006]

The object of the present invention is NO.
x, particularly when adding ammonia to the exhaust gas containing NOx and SOx at the same time and reacting catalytically, N is more than the catalyst conventionally proposed for removing nitrogen oxides.
The Ox removal rate is high, and the conversion rate to SO ₃ is low,
It is an object of the present invention to provide a catalyst for removing nitrogen oxides, which is useful as an industrial catalyst having excellent durability, and a method for producing the catalyst, which has good formability even for a catalyst having a complicated shape such as a honeycomb shape.

[0007]

Means for Solving the Problems The first aspect of the present invention is (1)
A basic aqueous solution is added to and neutralized with a mixed aqueous solution of a soluble titanium compound, a soluble silicon compound and / or a silica sol, or a mixed aqueous solution of a soluble titanium compound, a soluble tungsten compound, a soluble silicon compound and / or a silica sol to form a complex hydroxide ( y component) slurry is obtained,
Then, after adding metatitanic acid and a soluble silicon compound and / or silica sol to the composite hydroxide slurry,
Complex oxide (component A) obtained from a complex hydroxide (component a) slurry obtained by adding a basic aqueous solution and (2) at least one metal oxide selected from the group consisting of vanadium, molybdenum and tungsten And a substance (component B).

In the catalyst for removing nitrogen oxides, the amount of the composite oxide derived from the y component (Y component) contained in the composite oxide (A component) is preferably in the range of 5 to 30% by weight. .

The composition of the composite oxide derived from the y component (Y component) is in the range of 75 to 90% by weight as titanium oxide, 10 to 20% by weight as silicon oxide, and 0 to 5% by weight as tungsten oxide. Preferably there is.

It is preferable that the complex oxide (component A) contains 1 to 10% by weight of sulfate as SO _{4 based on the} oxide.

Further, the complex oxide (component A) is added to 85
~ 99.9 wt%, metal oxide (B component) 0.1 to 1
It is preferably contained in a proportion of 5% by weight.

The second aspect of the present invention is to add a basic aqueous solution to a mixed aqueous solution of a soluble titanium compound, a soluble silicon compound and / or a silica sol, or a mixed aqueous solution of a soluble titanium compound, a soluble tungsten compound, a soluble silicon compound and / or a silica sol. Obtained by adding a metatitanic acid slurry and a soluble silicon compound and / or silica sol to the composite hydroxide slurry after neutralization to obtain a composite hydroxide (y component) slurry, and then adding a basic aqueous solution. A complex oxide (component A) obtained by aging, washing, and drying a slurry of a complex hydroxide (the component A is the component a that is oxidized by the component a). (Since it has not been fired, it may still contain 1 part of hydroxide stage), vanadium, molybdenum, tan At least one metal oxide selected from the group consisting of stainless (B component) of the precursor (b
Component) and dried and calcined, or the composite hydroxide (a component) obtained by adding the basic aqueous solution to the composite oxide (component A) obtained by drying and calcining, Carrying at least one metal oxide (component B) selected from the group consisting of vanadium, molybdenum, and tungsten,
The present invention relates to a method for producing a nitrogen oxide removing catalyst, which is characterized by drying.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described in detail below.

In the catalyst for removing nitrogen oxides of the present invention, a mixed aqueous solution of a soluble titanium compound, a soluble silicon compound and / or silica sol, or a soluble titanium compound,
A composite hydroxide (y component) slurry obtained by adding and neutralizing a basic aqueous solution to a mixed aqueous solution of a soluble tungsten compound, a soluble silicon compound and / or silica sol is used. The composite hydroxide (y component) is a precursor that undergoes thermal history and is converted into a composite oxide (Y component). The complex oxide (Y component) is not a simple mixture of titanium oxide and silicon oxide, or titanium oxide, tungsten oxide and silicon oxide, but a so-called binary complex oxide (TiO ₂ —SiO ₂ ) or ternary system oxide. A composite oxide (TiO ₂ —WO ₃ —SiO ₂ ) is formed.

The complex oxide (component A) according to the present invention is obtained by adding metatitanic acid, a soluble silicon compound and / or silica sol to the above-mentioned complex hydroxide (component y) and then adding a basic aqueous solution. The obtained composite hydroxide (a
Ingredient) A substance whose slurry has undergone heat history. In the present invention, since such a special complex oxide (component A) is used as the catalyst component, a catalyst having high denitration activity and low SO ₂ oxidation activity and excellent durability can be obtained.

In the catalyst for removing nitrogen oxides of the present invention, the ratio (Y / A) of the composite oxide (Y component) derived from the y component contained in the composite oxide (A component) is 5 to 30% by weight. It is preferably in the range of. When the value of Y / A is smaller than 5% by weight, the denitration activity tends to be high, but the SO ₂ oxidation activity tends to be high, and when the value of Y / A is larger than 30% by weight, the catalyst The moldability tends to be poor, and the SO ₂ oxidation activity is low but the denitration activity is also low. The preferable range of Y / A is 10 to 20% by weight.

The composition of the composite oxide derived from the y component (Y component) is in the range of 75 to 90% by weight as titanium oxide, 10 to 20% by weight as silicon oxide, and 0 to 5% by weight as tungsten oxide. Preferably there is. When the amount of silicon oxide is less than 10% by weight, low SO ₂ oxidation activity may not be obtained, and when it is more than 20% by weight, the denitration activity becomes low and the formability becomes poor. There is. When the amount of tungsten oxide is more than 5% by weight, tungsten may exist without forming a complex oxide, which is not effective.

The composite oxide (component A) preferably contains 1 to 10% by weight of sulfate as SO ₄ . The inclusion of sulfate in component A tends to increase the denitration activity, and when it is less than 1% by weight, its effect is small, and when it is contained in more than 10% by weight, its effect is not changed. The preferred amount of sulfate is 2-8% by weight
Is the range.

The catalyst for removing nitrogen oxides of the present invention contains at least one metal oxide (component B) selected from the group consisting of vanadium, molybdenum and tungsten, but contains other metal oxides. May be. In particular,
Vanadium oxide and tungsten oxide are the preferred metal oxides.

In the catalyst for removing nitrogen oxides of the present invention, the composite oxide (component A) is 85 to 99.9% by weight, and the metal oxide (component B) is 0.1 to 15% by weight. It is preferable to contain. When the ratio of the B component is less than 0.1% by weight, the desired denitration activity may not be obtained, and when it exceeds 15% by weight, the SO ₂ oxidation activity may be increased. Preferably, the A component is 90 to
It is in the range of 99.5% by weight and the component B is 0.5 to 10% by weight.

Next, a method for producing the nitrogen oxide removing catalyst of the present invention will be described. Examples of soluble titanium compounds used in the method of the present invention include inorganic titanium compounds such as titanium chloride and titanium sulfate, and organic titanium compounds such as titanium oxalate and tetraisopropyl titanate, and the silicon source includes silica sol. Other examples of the soluble silicon compound include inorganic silicon compounds such as silicon tetrachloride and organic silicon compounds such as ethyl silicate and methyl silicate. Examples of soluble tungsten compounds include ammonium paratungstate and ammonium metatungstate.

In the method of the present invention, a mixed aqueous solution of the aforementioned soluble titanium compound and the aforementioned soluble silicon compound and / or silica sol, or the aforementioned soluble titanium compound, the aforementioned soluble tungsten compound and the aforementioned soluble silicon compound and / or Complex hydroxide (y component) by adding and neutralizing basic aqueous solution to mixed aqueous solution with silica sol
Although a slurry is prepared, it is desirable that the neutralization is performed within a pH range of 9 to 10.5. As the basic aqueous solution used in the present invention, known basic aqueous solutions such as ammonia water, urea aqueous solution and amine aqueous solution can be used, but ammonia aqueous solution is particularly preferable.

The above-mentioned composite hydroxide (y component) slurry is aged, if necessary, in the range of pH 9 to 10.5, and then the metatitanic acid slurry and the soluble silicon compound and / or silica sol are added to the slurry. Then, a composite hydroxide (a component) slurry obtained by adding a basic aqueous solution is prepared, and the pH of the composite hydroxide (a component) slurry is adjusted to a range of 9 to 10.5. desirable. The composite hydroxide (a component) slurry is, if necessary, aged and washed in the range of pH 9 to 10.5, and then at least one metal selected from the group consisting of vanadium, molybdenum and tungsten is added to the slurry. A precursor (component b) of the oxide (component B) and, if necessary, clay, a plasticizer, etc. are added, and the mixture is kneaded and kneaded to form a desired shape,
It is preferable to dry and bake at 300 to 800 ° C. In addition, other well-known supporting methods can be used for supporting the B component. For example, the above-mentioned composite hydroxide (a component) is formed into a desired shape, dried and baked to obtain a composite oxide (A component). After that, the component B can be impregnated.

An outline of the manufacturing method of the present invention is shown in the following flow sheet.

[Table 1]

As the precursor (component b) for forming at least one metal oxide (component B) selected from the group consisting of vanadium, molybdenum and tungsten, the vanadium source is ammonium metavanadate, vanadyl sulfate. , Vanadium oxalate, vanadium pentoxide, etc., examples of the molybdenum source include ammonium paramolybdate, molybdenum trioxide, etc., and examples of the tungsten source include ammonium paratungstate, tungsten oxide and the like.

The catalyst for removing nitrogen oxides of the present invention is NOx.
Exhaust gas containing nitrogen, especially N such as boiler exhaust gas
It is preferably used for a NOx removal method in which a reducing agent such as ammonia is added to exhaust gas containing Ox, SOx, heavy metals, and dust, and catalytically reduced. In addition, as the use conditions of the catalyst, ordinary denitration treatment conditions are adopted. Specifically, the reaction temperature is 150 to 600 ° C., and the space velocity is 1000 to
An example is a range of 100,000 hr ⁻¹ .

[0027]

The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.

Example 1 Titanyl sulfate crystal [TiO ₂ concentration 32 w as titanium source]
t%, manufactured by Teika Co., Ltd.] 4.22 kg, and water 16.
Silica sol (SiO ₂ concentration 20 wt%, trade name “Cataloid S-
20 ", 0.75 kg of Catalyst Kasei Kogyo Co., Ltd. is added and mixed for 15 minutes, and thereto, 9.11 kg of 3N ammonia water is added and neutralized for 15 minutes while maintaining the temperature at 60 ° C or lower. Then, the TiO ₂ —SiO ₂ composite hydroxide (y
Ingredients) A slurry was produced, and the pH was maintained at 9.5 to 10 and aged by heating at a temperature of 60 ° C for 1 hour. This obtained Ti
O ₂ -SiO ₂ composite hydroxide slurry to metatitanic acid slurry [TiO ₂ concentration 30 wt%, Ishihara Sangyo Co., Ltd.]
40.50 Kg was added in 10 minutes, and silica sol [SiO ₂ concentration 20 wt%, trade name “Cataloid S-2
0 ", manufactured by Catalysts & Chemicals Industry Co., Ltd.] 6.75 kg was added and mixed for 10 minutes, and then 3N ammonia water 2.43 K was added.
g was added to adjust the pH of the slurry to 9.5 to obtain a composite hydroxide (a component) slurry. After heating and aging the composite hydroxide slurry for 1 hour while maintaining the pH at 9.5 to 10 at 60 ° C., the composite hydroxide slurry was dehydrated and washed, and then dried at a temperature of 400 ° C. or less for 5 hours to obtain titanium. -A binary composite oxide (component A) made of silica was obtained. The SO ₄ content in the binary composite oxide was 4.7%. Next, 0.30 kg of monoethanolamine and 3.0 kg of water were mixed, to which 0.205 kg of ammonium metavanadate (component b) was added and dissolved by heating. This solution and the above-mentioned binary complex oxide (component A) 12.6
4 Kg was kneaded in a kneader, kneading and kneading were performed by adding a molding aid such as clay or glass fiber, and the mixture was extruded into a honeycomb shape. The moldability was good. Then, the molded product was dried at 110 ° C., and then calcined at 600 ° C. in a matsufur furnace to prepare a catalyst I.

Example 2 Titanyl sulfate crystal [TiO ₂ concentration 32 w as titanium source]
t%, manufactured by Teika Co., Ltd.] 12.70 kg, and water 5
2.25 kg of silica sol [SiO ₂ concentration 20 wt%, trade name “Cataloid S-20”, manufactured by Catalysts & Chemicals Industry Co., Ltd.] was added to an aqueous solution of titanyl sulfate dissolved and diluted in 0.80 Kg.
The mixture was added and mixed over 5 minutes, and 27.34 Kg of 3N ammonia water was added and neutralized over 15 minutes while maintaining the temperature at 60 ° C. or lower to TiO ₂ —SiO ₂ composite hydroxide (y component). Produces a slurry with a pH of 9.5-10
The temperature was maintained at 60 ° C. for 1 hour while aging by heating. To the obtained TiO ₂ —SiO ₂ composite hydroxide slurry, 31.50 kg of metatitanic acid slurry [TiO ₂ concentration 30 wt%, manufactured by Ishihara Sangyo Co., Ltd.] was added over 10 minutes, and silica sol [SiO ₂ concentration was added. 20 wt%, trade name “Cataloid S-20”, manufactured by Catalysts & Chemicals Co., Ltd.] 5.25
After adding and mixing Kg over 10 minutes, 1.89 Kg of 3N ammonia water was added to adjust the pH of the slurry to 9.5.
To prepare a composite hydroxide (a component) slurry. The composite hydroxide slurry had a pH of 9.5 to 10 at a temperature of 60 ° C.
After heating and aging for 1 hour while maintaining the above, the composite hydroxide slurry is dehydrated and washed, and then dried at a temperature of 400 ° C. or lower for 5 hours to obtain a binary composite oxide (component A) composed of titanium-silica. It was The SO ₄ content in the binary complex oxide was 4.9%. Next, monoethanolamine 0.3
0 Kg and 3.0 Kg of water were mixed, to which was added 0.205 Kg of ammonium metavanadate (component b) and the mixture was heated and dissolved. This solution and 12.64 kg of the above-mentioned binary complex oxide (A component) are kneaded in a kneader, further kneaded and kneaded with a molding aid such as clay or glass fiber, and then extruded into a honeycomb shape. However, the moldability was good. Then, the molded product was dried at 110 ° C., and then calcined at 600 ° C. in a pineapple furnace to prepare catalyst II.

Example 3 Titanyl sulfate crystal [TiO ₂ concentration 32 w as titanium source]
t%, manufactured by Teika Co., Ltd.] 1.88 kg, water 7.5
Silica sol [SiO ₂ concentration 20 wt%, trade name "Cataloid S-2" in an aqueous solution of titanyl sulfate dissolved and diluted to 2 kg.
0 ", manufactured by Catalyst Kasei Kogyo Co., Ltd.] 0.75 Kg was added and mixed over 15 minutes, and 4.05 Kg of 3N ammonia water was added and neutralized over 15 minutes while maintaining the temperature at 60 ° C or lower. Then, a TiO ₂ —SiO ₂ composite hydroxide (y component) slurry was generated, and further, the pH was maintained at 9.5 to 10 and aged by heating at a temperature of 60 ° C. for 1 hour.
To ₂ -SiO ₂ composite hydroxide (y component) slurry, metatitanic acid slurry [TiO ₂ concentration 30 wt%, manufactured by Ishihara Sangyo Kaisha, Ltd.] was added over 38.00Kg 10 minutes, further a silica sol [SiO ₂ concentration 20wt %, Trade name “Cataloid S-20”, manufactured by Catalysts & Chemicals Co., Ltd.] 14.25
After adding and mixing Kg over 10 minutes, 2.28 Kg of 3N aqueous ammonia was added to adjust the pH of the slurry to 9.5.
To prepare a composite hydroxide (a component) slurry. The composite hydroxide slurry had a pH of 9.5 to 10 at a temperature of 60 ° C.
After heating and aging for 1 hour while maintaining the temperature, this composite hydroxide slurry is dehydrated and washed, and then dried at a temperature of 400 ° C. or lower for 5 hours to obtain a binary composite oxide (component A) composed of titanium-silica. It was The SO ₄ content in the binary complex oxide was 4.9%. Next, monoethanolamine 0.3
0 Kg and 3.0 Kg of water were mixed, to which was added 0.205 Kg of ammonium metavanadate (component b) and the mixture was heated and dissolved. This solution and 12.64 kg of the above-mentioned binary complex oxide (component A) are kneaded in a kneader, and a molding aid such as clay or glass fiber is further added, and the mixture is kneaded and kneaded, and then extruded into a honeycomb shape. However, the moldability was good. After that, the molded product was dried at 110 ° C.
Catalyst III was prepared by calcining at 00 ° C.

Example 4 Titanyl sulfate crystal [TiO ₂ concentration 32 w as titanium source]
t%, manufactured by Teika Co., Ltd.] 7.50 kg, and water 30.
Silica sol [SiO ₂ concentration 20 wt%, trade name “Cataloid S-
20 ", manufactured by Catalysts & Chemicals Industry Co., Ltd.] 3.00 Kg was added and mixed over 15 minutes, and 16.20 Kg of 3N ammonia water was added and neutralized over 15 minutes while maintaining the temperature at 60 ° C or lower. Then, a TiO ₂ —SiO ₂ composite hydroxide (y component) slurry was generated, and further maintained at pH 9.5 to 10 and aged by heating at 60 ° C. for 1 hour.
32.00 Kg of metatitanic acid slurry [TiO ₂ concentration 30 wt%, manufactured by Ishihara Sangyo Co., Ltd.] was added to O ₂ —SiO ₂ composite hydroxide (y component) slurry over 10 minutes, and silica sol [SiO ₂ concentration was added. 20 wt%, trade name "Cataloid S-20", manufactured by Catalyst Kasei Kogyo Co., Ltd.] 12.0
After 0 Kg was added and mixed for 10 minutes, 1.92 Kg of 3N ammonia water was added to adjust the pH of the slurry to 9.
5 was obtained to obtain a composite hydroxide (a component) slurry.
The composite hydroxide slurry had a pH of 9.5 to 1 at a temperature of 60 ° C.
After heating and aging for 1 hour while maintaining 0, the composite hydroxide slurry was dehydrated and washed, and then 5 times at a temperature of 400 ° C. or lower.
After drying for an hour, a binary composite oxide (component A) composed of titanium-silica was obtained. The SO ₄ content in the binary complex oxide was 4.9%. Next, 0.30 kg of monoethanolamine and 3.0 kg of water are mixed, and 0.205 kg of ammonium metavanadate (component b) is added thereto,
It melted by heating. This solution and 12.64 kg of the above-mentioned binary complex oxide (A component) are kneaded in a kneader, and a molding aid such as clay or glass fiber is further added and kneaded and kneaded, followed by extrusion molding into a honeycomb shape. However, the moldability was good. Then, the molded product was dried at 110 ° C. and then calcined at 600 ° C. in a pine-furnace to prepare a catalyst IV.

Example 5 Titanyl sulfate crystal [TiO ₂ concentration 32 w as titanium source]
t%, manufactured by Teika Co., Ltd.] 7.50 kg, and water 30.
Silica sol [SiO ₂ concentration 20 wt%, trade name “Cataloid S-
20 ", manufactured by Catalysts & Chemicals Industry Co., Ltd.] 2.10 Kg was added and mixed over 15 minutes, and 0.17 Kg ammonium paratungstate crystal was added, and the temperature was 60 ° C.
16.20 Kg of 3N ammonia water while maintaining the following
Is added / neutralized over 15 minutes to form TiO ₂ —SiO ₂ —
A WO ₃ composite hydroxide (y component) slurry was produced, and the temperature was maintained at pH 9.5 to 10 and aged by heating at 60 ° C. for 5 hours. The obtained TiO ₂ —SiO ₂ —WO ₃ composite hydroxide (y component) slurry was added to a metatitanic acid slurry [TiO 2
₂ concentration 30 wt%, Ishihara Sangyo Co., Ltd.] 32.00 Kg
Was added over 10 minutes, and silica sol [SiO ₂
Concentration 20 wt%, trade name "Cataloid S-20", manufactured by Catalysts & Chemicals Industry Co., Ltd.] 12.00 Kg was added and mixed over 10 minutes, and then 3N ammonia water 1.92 Kg was added to adjust the pH of the slurry. It was adjusted to 9.5 to obtain a composite hydroxide (a component) slurry. The composite hydroxide slurry was heated and aged for 1 hour while maintaining the pH at 9.5 to 10 at a temperature of 60 ° C., then the composite hydroxide slurry was dehydrated and washed, and then dried at a temperature of 400 ° C. or lower for 5 hours. Ternary complex oxide composed of titanium-silica-tungsten (component A)
Got The SO ₄ content in the ternary complex oxide was 4.9.
%Met. Next, monoethanolamine 0.30K
g and water (3.0 kg) were mixed, and ammonium metavanadate (b component) (0.205 kg) was added thereto and dissolved by heating. This solution and the above-mentioned ternary complex oxide (component A) 1
2.64 kg was kneaded with a kneader, kneading and kneading were performed by adding a molding aid such as clay or glass fiber, and extrusion molding was performed into a honeycomb shape, but the moldability was good. Then, the molded product was dried at 110 ° C. and then calcined at 600 ° C. in a pineapple furnace to prepare a catalyst V.

Example 6 Titanyl sulfate crystal [TiO ₂ concentration 32 w as titanium source]
t%, manufactured by Teika Co., Ltd.] 7.50 kg, and water 30.
Silica sol [SiO ₂ concentration 20 wt%, trade name “Cataloid S-
20 ", manufactured by Catalysts & Chemicals Industry Co., Ltd.] 2.10 Kg was added and mixed over 15 minutes, while maintaining the temperature below 60 ° C.
16.20 kg of specified ammonia water is added and neutralized over 15 minutes to form a TiO ₂ —SiO ₂ composite hydroxide (y component).
A slurry was produced, and the pH was maintained at 9.5 to 10 and aged by heating at a temperature of 60 ° C. for 5 hours. Obtained TiO ₂ -Si
O ₂ composite hydroxide slurry metatitanic acid slurry [T
iO ₂ concentration 30 wt%, Ishihara Sangyo Co., Ltd.] 32.00
Kg was added over 10 minutes, and silica sol [Si
O ₂ concentration 20 wt%, trade name “Cataloid S-20”,
Catalyst Catalysis Co., Ltd.] 12.00 Kg was added and mixed for 10 minutes, and then 3N ammonia water 1.92 Kg was added to adjust the pH of the slurry to 9.5 to prepare a composite hydroxide (a). Ingredient) A slurry was obtained. After heating and aging the composite hydroxide slurry at a temperature of 60 ° C. for 1 hour while maintaining pH 9.5 to 10, the composite hydroxide (a component) slurry was dehydrated and washed, and then at a temperature of 400 ° C. or lower for 5 hours. It was dried to obtain a binary composite oxide (component A) composed of titanium-silica. The SO ₄ content in the binary complex oxide was 4.9%. Next, 0.30 Kg of monoethanolamine and 3.0 Kg of water were mixed, and 0.205 Kg of ammonium metavanadate (component b) was added thereto and heated and dissolved.
This solution and the above-mentioned binary complex oxide (component A) 12.
64 kg, further 0.17 kg ammonium paratungstate crystal was added, and this was kneaded in a kneader, and further, a molding aid such as clay or glass fiber was added and kneaded and kneaded, and then extruded into a honeycomb shape. The moldability was good. Then, the molded product was dried at 110 ° C. and then calcined at 600 ° C. in a pine-furnace to prepare a catalyst VI.

Comparative Example 1 Titanyl sulfate crystal [TiO ₂ concentration 32 w as titanium source]
t%, manufactured by Teika Co., Ltd.] 43.60 kg, and water 17
5.25 Kg of silica sol [SiO ₂ concentration 20 wt%, trade name “Cataloid S-20”, manufactured by Catalysts & Chemicals Industry Co., Ltd.] was added to an aqueous solution of titanyl sulfate dissolved and diluted to 4.40 Kg.
The mixture was added and mixed over 5 minutes, and 94.16 Kg of 3N ammonia water was added and neutralized over 15 minutes while maintaining the temperature at 60 ° C. or lower to TiO ₂ —SiO ₂ composite hydroxide (y component). Produces a slurry with a pH of 9.5-10
The temperature was maintained at 60 ° C. for 1 hour while aging by heating. Obtained T
After dehydration cleaning of the iO ₂ —SiO ₂ composite hydroxide slurry,
It was dried at a temperature of 400 ° C. or lower for 5 hours to obtain a binary composite oxide (Y component) composed of titanium-silica. The SO ₄ content in the binary complex oxide was 6.9%. Next, 0.30 kg of monoethanolamine and 3.0 kg of water
Was mixed, to this was added 0.205 Kg of ammonium metavanadate (component b), and the mixture was heated and dissolved. 12.64 Kg of the above-mentioned binary complex oxide (Y component) was added to this solution, and this was kneaded with a kneader. Further, a molding aid such as clay or glass fiber was added, and after kneading and kneading, It was extruded into a honeycomb shape, but it was difficult to form into a honeycomb shape. The sample for activity measurement was somehow molded, and the obtained molded product was dried at 110 ° C., and then calcined at 600 ° C. in a pine fur furnace to prepare a catalyst VII.

Comparative Example 2 Metatitanic acid slurry [TiO ₂ concentration 30 wt%, Ishihara Sangyo Co., Ltd.] 40.00 kg and silica sol [SiO ₂
20 wt% concentration, trade name "Cataloid S-20", manufactured by Catalysts & Chemicals Industry Co., Ltd.] 15.00 Kg was mixed, and then 10.80 Kg of 3N ammonia water was added to adjust the pH of the slurry to 9.5. Then, a composite hydroxide slurry was obtained.
The composite hydroxide slurry had a pH of 9.5 to 1 at a temperature of 60 ° C.
After heating and aging for 1 hour while maintaining 0, the composite hydroxide slurry was dehydrated and washed, and then dried at a temperature of 400 ° C. or lower for 5 hours to obtain a binary composite oxide composed of titanium-silica. . The SO ₄ content in the binary complex oxide is 4.
It was 2%. Next, monoethanolamine 0.30K
g and water (3.0 kg) were mixed, and ammonium metavanadate (b component) (0.205 kg) was added thereto and dissolved by heating. This solution and the above-mentioned binary complex oxide 12.64K
g was kneaded with a kneader, kneading was further performed by adding a molding aid such as clay or glass fiber, and the mixture was kneaded and kneaded, and then extrusion-molded into a honeycomb shape, but the moldability was good. Then, the molded product 11
After being dried at 0 ° C., it was calcined at 600 ° C. in a pine oven to prepare catalyst VIII.

Example of Use of Catalyst The denitration performance of the catalysts I to VIII of Examples 1 to 6 and Comparative Examples 1 and 2 was evaluated. In the denitration performance test, each honeycomb catalyst (cell pitch 7.4 mm, wall thickness 1.0 mm) cut into 3 × 3 pieces with a length of 300 mm was filled in a flow reactor, and the denitration rate was measured under the following conditions. . The denitrification rate is obtained by measuring the nitrogen oxide NOx concentration in the gas before and after contacting the catalyst with a Chemilumi type nitrogen oxide analyzer and using the following equation.

[Equation 1] Denitration rate (volume%) = [NOx in non-contact gas
(Volume ppm) -NOx in contact gas (Volume ppm)]
÷ [NOx in non-contact gas (volume ppm)] x 100 Test condition Catalyst shape: 3 x 3 mesh, length: 300 mm Reaction temperature: 380 ° C., SV = 10,000 hr^-1 Gas composition: NOx = 180 volume ppm, NH_Three= 216
Capacity ppm, O_Two= 2% by volume, SO_Two= 500 capacity pp
m, H_TwoO = 10% by volume, N_Two= Balance In addition, the SOx oxidation capacity test was conducted using a honeycomb catalyst with a length of 30
Fill the flow-type reactor with 0 mm cut into 3 x 3 pieces.
And SO under the following conditions_ThreeThe conversion rate was measured. SO_ThreeConversion
The ratio is SO in the gas before and after contact with the catalyst._TwoConcentration is infrared type S
O_TwoMeasured with a gas concentration meter and calculated by the following formula
Of.

[Equation 2] SO_ThreeConversion rate (% by volume) = [S in non-contact gas
O_Two(Volume ppm) -SO in contact gas_Two(Capacity pp
m)] ÷ [SO in uncontacted gas_Two(Capacity ppm)] × 1
00 Test condition Catalyst shape: 3 x 3 mesh, length: 300 mm Reaction temperature: 380 ° C., SV = 10,000 hr^-1 Gas composition: O_Two= 2% by volume, SO_Two= 500 capacity pp
m, N_Two= Balance The evaluation results are shown in Table 1.

[0037]

[Table 2]

[0038]

As is apparent from the table, the catalyst of the present invention is an excellent catalyst showing an extremely low SO ₃ conversion rate while maintaining a high denitration rate. The difference of ± 0.01% is a significant difference when the SO ₃ conversion rate is 0.20% or less. A catalyst having such performance is extremely effective as a catalyst for treating boiler exhaust gas that uses a fuel containing a large amount of sulfur components. Further, since the catalyst of the present invention has good moldability even when formed into a honeycomb shape, it has high productivity as an industrial catalyst.

Continued front page    (72) Inventor Koji Masuda             13-2 Kitaminato-cho, Wakamatsu-ku, Kitakyushu, Fukuoka             Kasei Industry Co., Ltd. Wakamatsu factory (72) Inventor Masaaki Uchida             13-2 Kitaminato-cho, Wakamatsu-ku, Kitakyushu, Fukuoka             Kasei Industry Co., Ltd. Wakamatsu factory (72) Inventor Kazuhiro Nishii             Kanagawa Prefecture Yokohama City Totsuka Ward Kawakami Town 645-4-301 F-term (reference) 4D048 AA06 AB02 AC04 BA06X                       BA07X BA23X BA26Y BA27X                       BA42X BA46X BB02                 4G069 AA03 AA08 BA02A BA02B                       BA04A BA04B BA20A BA20B                       BA21C BA47C BB04A BB04B                       BB06A BB06B BB08C BB10A                       BB10B BB10C BC50C BC54A                       BC54B BC59A BC60A BC60B                       BC60C BD01C BD02C BD05C                       BD06C BD12C BE06C BE08C                       CA02 CA08 CA13 EA19 FA01                       FA02 FB06 FB08 FB09 FB57                       FB67 FC01 FC03 FC08

Claims (6)

[Claims] 1. A mixed aqueous solution of a soluble titanium compound, a soluble silicon compound and / or a silica sol, or a soluble titanium compound, a soluble tungsten compound,
A basic aqueous solution is added to and neutralized with a mixed aqueous solution of a soluble silicon compound and / or silica sol to form a composite hydroxide (y
Component) slurry is obtained, and then metatitanic acid, a soluble silicon compound and / or silica sol are added to the composite hydroxide slurry, and then a basic aqueous solution is added to obtain a composite hydroxide (a component) slurry. Catalyst for removing nitrogen oxides, which contains a complex oxide (component A) and (2) at least one metal oxide (component B) selected from the group consisting of vanadium, molybdenum and tungsten. . 2. The amount of the composite oxide (Y component) derived from the y component contained in the composite oxide (A component) is 5 to 30.
The nitrogen oxide removing catalyst according to claim 1, which is in a range of weight%. 3. A composite oxide derived from the y component (Y component).
The catalyst for removing nitrogen oxides according to claim 1 or 2, wherein the composition is in the range of 75 to 90% by weight as titanium oxide, 10 to 20% by weight as silicon oxide, and 0 to 5% by weight as tungsten oxide. 4. The catalyst for removing nitrogen oxides according to claim 1, wherein the complex oxide (component A) contains 1 to 10% by weight of SO ₄ as SO ₄ based on the oxide. 5. The composite oxide (component A) is added to 85-9.
The nitrogen oxide removing catalyst according to any one of claims 1 to 4, which contains 9.9% by weight and a metal oxide (component B) in a proportion of 0.1 to 15% by weight. 6. A basic aqueous solution is added to and neutralized with a mixed aqueous solution of a soluble titanium compound, a soluble silicon compound and / or a silica sol, or a mixed aqueous solution of a soluble titanium compound, a soluble tungsten compound, a soluble silicon compound and / or a silica sol. Complex hydroxide (y component)
A slurry is obtained, and then a metatitanic acid slurry, a soluble silicon compound and / or a silica sol are added to the composite hydroxide slurry, and then a basic aqueous solution is added to obtain the composite hydroxide (a hydroxide of the component a). It is the component A that has been oxidized into a complex oxide) The complex oxide (component A) obtained by aging, washing and drying the slurry (since it has not been fired, it is still in the hydroxide stage). (A component may be contained in 1 part), and a precursor (component b) of at least one metal oxide (component B) selected from the group consisting of vanadium, molybdenum, and tungsten is supported, dried, and fired. Or the complex oxide (component A) obtained by drying and firing the complex hydroxide (component a) obtained by adding the basic aqueous solution to vanadium, molybdenum, or tungsten. At least one metal oxide (B component) carrying method of the nitrogen oxide removing catalyst, characterized by drying selected from the group consisting.