JP2003093880A - Catalyst for removing nitrogen oxides and method for producing the same - Google Patents

Abstract

(57) [Abstract] (with correction) [PROBLEMS] To add ammonia to exhaust gas containing NO _X and SO _X at the same time, and carry out SO ₃
Provided is a catalyst for removing nitrogen oxides, which has a low conversion rate to nitrogen and has excellent durability. SOLUTION: A mixed aqueous solution of a soluble titanium compound, a soluble silicon compound and / or a silica sol, or
Further, a slurry obtained by neutralizing a mixed aqueous solution to which a soluble tungsten compound is added, a mixed aqueous solution of a metatitanic acid slurry and a soluble silicon compound and / or a silica sol, or a mixed aqueous solution to which a soluble tungsten compound is further added is obtained. A catalyst for removing nitrogen oxides containing the obtained composite oxide (component A) and an oxide of at least one metal selected from the group consisting of vanadium, molybdenum and tungsten (component B) using the obtained slurry. Its manufacturing method.

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 of various factories. The present invention relates to a catalyst for removing nitrogen oxides (hereinafter abbreviated as NO _X ) contained in exhaust gas and a method for producing the same.

[0002]

2. Description of the Related Art As a denitration catalyst for removing NO _X 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. It is used industrially. Since a denitration catalyst used industrially needs to deal with dust, sulfur compounds (hereinafter abbreviated as SO _X ) and the like contained in exhaust gas, not only is the denitration activity high, Ability to oxidize to SO ₃ (SO
₃ various performances such as conversion) is low is required.

In general, most of SO _X contained in 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. Combines with the unreacted component of ₃ 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 nitrogen, a soluble titanium compound and a soluble silicon compound and / or silica sol are used as starting materials, and the materials are neutralized with ammonia in an aqueous medium. A coprecipitate was obtained by agitation, and the coprecipitate slurry was aged in a pH range of 8.5 or more for 20 hours or more, washed, dried, and then calcined to obtain titanium and silicon. The binary composite oxide is used as a catalyst (a) component, vanadium oxide as a catalyst (b) component, and tungsten oxide as a catalyst (c) component. .About.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 70 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.
_When adding ammonia to the exhaust gas containing _{X 2} , especially NO _X and SO _X at the same time and reacting them catalytically, N is more than the conventionally proposed catalyst for removing nitrogen oxides.
Higher O _X removal rate, yet low conversion to SO _3,
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]

The first aspect of the present invention is to provide a mixed aqueous solution of a soluble titanium compound, a soluble silicon compound and / or a silica sol, or a soluble titanium compound,
Composite hydroxide (x 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 a silica sol, a metatitanic acid slurry and a soluble silicon compound and / or silica sol Or a complex hydroxide (y component) slurry obtained by adding and neutralizing a basic aqueous solution to a mixed aqueous solution of metatitanic acid, a mixed aqueous solution of a soluble tungsten compound, a soluble silicon compound and / or silica sol. Composite oxide (component A)
And a catalyst for removing nitrogen oxides, which contains an oxide (component B) of at least one metal selected from the group consisting of vanadium, molybdenum and tungsten.

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

The composition of the composite oxide (component A) is such that titanium oxide is 75 to 90% by weight, silicon oxide is 10 to 20% by weight, and tungsten oxide is 0 to 5% by weight.
It is preferably in the range of% by weight.

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 (1) 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 a base. Aqueous aqueous solution is added and neutralized to obtain slurry of complex hydroxide (component x), (2) Separately,
A mixed aqueous solution of a metatitanic acid slurry and a soluble silicon compound and / or a silica sol, or a mixed aqueous solution of a metatitanic acid slurry, a soluble tungsten compound, a soluble silicon compound and / or a silica sol, to which a basic aqueous solution is added and neutralized to form a composite hydroxide. (Y component) A slurry is obtained, and (3) the composite water obtained by mixing the slurry of the composite hydroxide of the x component and the slurry of the composite hydroxide of the y component, followed by washing and drying. A precursor (component b) of an oxide of at least one metal selected from the group consisting of vanadium, molybdenum and tungsten is supported on an oxide (component a) or a complex oxide (component A), and dried and calcined. The present invention also relates to a method for producing a nitrogen oxide removing catalyst.

[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 (component x) 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 complex hydroxide (component x) is a precursor that is converted into a complex oxide (component A) by undergoing heat history in a mixed state with another complex hydroxide (component y). The complex oxide (component A) is not a mere 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 composite oxide _(TiO 2 -WO
₃ to form a -SiO _2).

A mixed aqueous solution of the metatitanic acid slurry of the present invention and a soluble silicon compound and / or silica sol,
Alternatively, a composite hydroxide (y component) slurry obtained by adding and neutralizing a basic aqueous solution to a mixed aqueous solution of a metatitanic acid slurry, a soluble tungsten compound, a soluble silicon compound and / or silica sol is the above-mentioned composite hydroxide ( It is a precursor that undergoes a thermal history in the mixed state with the x component) and is converted into a composite oxide (A component). The complex oxide (component A) 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 composite oxide _(TiO 2 -WO
₃ to form a -SiO ₂₎ are the same as defined above.

The composite oxide which is the A component in the present invention is a catalyst obtained by heat-treating a mixture of the slurry of the composite hydroxide which is the x component and the slurry of the composite hydroxide which is the y component. Since it is a component, the resulting catalyst has high denitrification activity and low SO ₂ oxidation activity, and is excellent in durability.

In the nitrogen oxide removing catalyst of the present invention, the amount (x / A) of the composite oxide derived from the x component contained in the composite oxide (A component) is in the range of 5 to 30% by weight. It is preferable. When the value of x / A is less than 5% by weight, the denitrification activity tends to be high, but the SO ₂ oxidation activity tends to be high, and when the value of x / A is greater than 30% by weight, The moldability of the catalyst tends to deteriorate, and
The SO ₂ oxidation activity is low, but the denitrification activity also tends to be low. The preferable range of x / A is 10 to 20% by weight.

The composition of the composite oxide (component A) is 75 to 90% by weight as titanium oxide, 10 to 20% by weight as silicon oxide, and 0 to 5 as tungsten oxide.
It is preferably in the range of% by weight. 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, denitrification activity becomes low and moldability deteriorates. Sometimes. On the other hand, if the amount of tungsten oxide is more than 5% by weight, tungsten may exist in a state where complex hydroxide is not formed, which is not effective.

The complex oxide (component A) preferably contains 1 to 10% by weight of sulfate as SO _{4 based on the} oxide. 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 in the range of 2 to 8% by weight.

The catalyst for removing nitrogen oxides of the present invention contains an oxide (component B) of at least one metal selected from the group consisting of vanadium, molybdenum and tungsten, but does not contain other metal oxides. May be.
In particular, vanadium oxide and tungsten oxide are suitable metal oxides. The catalyst for removing nitrogen oxides of the present invention,
It is preferable that the composite oxide (component A) is contained in a proportion of 85 to 99.9% by weight and the metal oxide (component B) is contained in a proportion of 0.1 to 15% by weight. B component is 0.1% by weight
If the amount is less than the above, the desired denitrification activity may not be obtained, and if it exceeds 15% by weight, the SO ₂ oxidation activity may be increased. Preferably, the A component is 9
0 to 99.5% by weight, and B component 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 the soluble titanium compound 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. Examples of soluble silicon compounds 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 (x component) by adding and neutralizing basic aqueous solution to mixed aqueous solution with silica sol
Although a slurry is prepared, neutralization is preferably carried out within a pH range of 9 to 10.5, and more preferably aged 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.

In the method of the present invention, in addition to the slurry of the composite hydroxide as the component x, a mixed aqueous solution of the metatitanic acid slurry and the soluble silicon compound and / or silica sol, or the metatitanic acid slurry, the soluble tungsten compound, the soluble A basic aqueous solution is added to and neutralized with a mixed aqueous solution of a silicon compound and / or silica sol to prepare a composite hydroxide (y component) slurry.
It is desirable to carry out in the range of H9 to 10.5.
Aging in the range of H9 to 10.5 is particularly desirable. Also in this case, the above-mentioned basic aqueous solution can be used.

The composite hydroxide (a component) or the composite obtained by mixing the slurry of the composite hydroxide as the x component and the slurry of the composite hydroxide as the y component, and then washing and drying the mixture. As the oxide (component A), a precursor (b component) of an oxide of at least one metal selected from the group consisting of vanadium, molybdenum and tungsten, and clay,
It is preferable to add a plasticizer and the like, knead and knead, form into a desired shape, dry and calcination at 300 to 800 ° C.

The precursor of the component b includes ammonium vanadium as a vanadium source, vanadyl sulfate, vanadyl oxalate, vanadium pentoxide, etc., ammonium as a molybdenum source, ammonium paramolybdate, molybdenum trioxide, etc. Examples include ammonium paratungstate and tungsten oxide. A well-known supporting method can be adopted for supporting the component b. For example, the composite hydroxide (component a) described above is molded into a desired shape and dried,
It can also be prepared by impregnating the composite oxide (component A) obtained by firing with the precursor of component B (component b) or component B.

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

[Table 1]

The catalyst for removing nitrogen oxides of the present invention is NO _x.
Exhaust gas containing NO, especially NO such as boiler exhaust gas
It is suitable for use in a NO _X removal method in which a reducing agent such as ammonia is added to an exhaust gas containing not only _{X 2} and SO _X but also heavy metals and dusts to carry out catalytic reduction. The conditions for using the catalyst are normal denitration treatment conditions, specifically, a reaction temperature of 150 to 600 ° C. and a space velocity of 1,000 to
For example, the range of 100,000 hr ⁻¹ is exemplified.

[0028]

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

Example 1 As a titanium source, 4.22 kg of titanyl sulfate crystal [TiO ₂ concentration 32% by weight, manufactured by Teika Co., Ltd.] was taken, and water 16.
Silica sol [SiO ₂ concentration 20% by weight, trade name “Cataloid S-
20 L "catalyst manufactured by Kasei Kogyo Co., Ltd.] 0.75 kg was added and mixed over 15 minutes, and thereto, 9.11 kg of 3N ammonia water was added and neutralized over 15 minutes while maintaining the temperature at 60 ° C or lower. TiO ₂ —SiO ₂ composite hydroxide (x
Ingredients) A slurry was produced, and the pH was maintained at 9.5 to 10 and aged by heating at 60 ° C for 1 hour. Separately, to 40.5 kg of metatitanic acid slurry [TiO ₂ concentration 30% by weight, manufactured by Ishihara Sangyo Co., Ltd.], silica sol [SiO ₂ concentration 20% by weight, trade name “Cataloid S-20L” manufactured by Catalysts & Chemicals Industry Co., Ltd.] After 6.75 kg was added and mixed for 10 minutes, 2.43 kg of 3N ammonia water was added and neutralized, pH was maintained at 9.5 to 10, and the mixture was aged by heating at 60 ° C. for 5 hours to prepare the y component. A composite hydroxide slurry was prepared. After mixing and stirring the slurry of the composite hydroxide of the above-mentioned x component with the slurry of the composite hydroxide of this y component, this mixture slurry is dehydrated and washed at 400 ° C.
It was dried at the following temperature for 5 hours to obtain a binary composite oxide (component A) composed of TiO ₂ —SiO ₂ . The SO ₄ content in the binary composite oxide was 4.7% by weight.
Next, 0.3 kg of monoethanolamine and 3.0 kg of water
And mixed with ammonium metavanadate 0.20
5 kg was added and dissolved by heating. This solution and 12.64 kg of the above-mentioned binary complex oxide (component A) were kneaded by a kneader, further kneaded and kneaded with a molding aid such as clay or glass fiber, and 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 muffle furnace to prepare a catalyst I.

Example 2 As a titanium source, 12.7 kg of titanyl sulfate crystal [TiO ₂ concentration 32% by weight, manufactured by Teika Co., Ltd.] was taken, and water 50.
Silica sol [SiO ₂ concentration 20% by weight, trade name "Cataloid S-2" was added to an aqueous solution of titanyl sulfate dissolved and diluted in 8 kg.
0L "catalyst manufactured by Kasei Kabushiki Kaisha] 2.25 kg was added and mixed over 15 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. A TiO ₂ —SiO ₂ composite hydroxide (x component) slurry was generated, and further maintained at pH 9.5 to 10 and aged by heating for 1 hour at a temperature of 60 ° C. Separately, metatitanic acid slurry [TiO ₂ concentration 30 wt%. , Ishihara Sangyo Co., Ltd.
31.5 kg, silica sol [SiO ₂ concentration 20% by weight, trade name “Cataloid S-20L” manufactured by Catalysts & Chemicals Industries Ltd.] 5.25 kg was added and mixed for 10 minutes, and then 3N ammonia water 1 was added. .89 kg was added and neutralized,
The pH was maintained at 9.5 to 10 and the mixture was aged at 60 ° C. for 5 hours to prepare a slurry of a composite hydroxide corresponding to the y component. After the slurry of the composite hydroxide of the y component described above is mixed and stirred with the slurry of the composite hydroxide of the y component, the mixture slurry is dehydrated and washed, and dried at a temperature of 400 ° C. or lower for 5 hours to form TiO 2. binary composite oxide consisting of ₂ -SiO ₂ the (a component) was obtained. The SO ₄ content in the binary composite oxide was 4.9% by weight. Next, 0.3 kg of monoethanolamine and 3.0 kg of water were mixed, and to this was added ammonium metavanadate 0.205.
kg was added and dissolved by heating. This solution and 12.64 kg of the above-mentioned binary complex oxide (component A) were kneaded by a kneader, further kneaded and kneaded with a molding aid such as clay or glass fiber, and 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 muffle furnace to prepare a catalyst II.

Example 3 As a titanium source, 1.88 kg of titanyl sulfate crystal [TiO ₂ concentration 32% by weight, manufactured by Teika Co., Ltd.] was taken, and water 7.5 was used.
Silica sol [SiO ₂ concentration 20% by weight, trade name "Cataloid S-2" was added to an aqueous solution of titanyl sulfate dissolved and diluted in 2 kg.
0L "catalyst manufactured by Kasei Kogyo Co., Ltd.] 0.75 kg was added and mixed for 15 minutes, and 4.05 kg of 3N ammonia water was added and neutralized for 15 minutes while maintaining the temperature at 60 ° C or lower. To produce a TiO ₂ —SiO ₂ composite hydroxide (component x) slurry, which was further maintained at pH 9.5 to 10 and aged for 1 hour at a temperature of 60 ° C. Separately, metatitanic acid slurry [TiO ₂ concentration 30 % By weight, Ishihara Sangyo Co., Ltd.] 38.0 kg, silica sol [SiO ₂ concentration 2
0% by weight, trade name “Cataloid S-20L” manufactured by Catalysts & Chemicals Industry Co., Ltd.] 14.2 kg was added and mixed over 10 minutes, then 2.28 kg of 3N ammonia water was added and neutralized, and the pH was adjusted to 9. The temperature was maintained at 5 to 10 and aged by heating at a temperature of 60 ° C. for 5 hours to prepare a slurry of the composite hydroxide as the y component. After the slurry of the composite hydroxide corresponding to the y component is mixed with the slurry of the composite hydroxide corresponding to the x component, the mixture slurry is dehydrated and washed to obtain 400
It was dried at a temperature of ℃ or less for 5 hours to obtain a binary composite oxide (Component A) composed of TiO ₂ —SiO ₂ . The SO ₄ content in the binary composite oxide was 4.9% by weight. Next, 0.3 kg of monoethanolamine and 3.0 of water
kg, and ammonium metavanadate of 0.
205 kg was added and dissolved by heating. This solution and 12.64 kg of the above-mentioned binary complex oxide (component A) were kneaded by a kneader, further kneaded and kneaded with a molding aid such as clay or glass fiber, and 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 muffle furnace to prepare catalyst II.
I was prepared.

Example 4 As a titanium source, 7.5 kg of titanyl sulfate crystal [TiO ₂ concentration 32% by weight, manufactured by Teika Co., Ltd.] was taken, and water 30.0 was used.
Silica sol [SiO ₂ concentration 20% by weight, trade name “Cataloid S-2
0L "Catalyst Kasei Kogyo Co., Ltd.] 3.0 kg was added and mixed over 15 minutes, and 16.2 kg of 3N ammonia water was added and neutralized over 15 minutes while maintaining the temperature at 60 ° C or lower. TiO ₂ —SiO ₂ composite hydroxide (x component)
A slurry was produced, the pH was maintained at 9.5 to 10, and the mixture was aged by heating at a temperature of 60 ° C. for 1 hour. Separately, metatitanic acid slurry [TiO ₂ concentration 30% by weight, manufactured by Ishihara Sangyo Co., Ltd.]
To 32.0 kg, 12.0 kg of silica sol [SiO ₂ concentration 20% by weight, trade name “Cataloid S-20L” manufactured by Catalysts & Chemicals Industry Co., Ltd.] was added and mixed for 10 minutes, and then 3N ammonia water 1.92 kg was added and mixed. Add / neutralize
Furthermore, the pH was maintained at 9.5 to 10 and the mixture was heated and aged at a temperature of 60 ° C. for 5 hours to prepare a slurry of the composite hydroxide as the y component. The slurry of the composite hydroxide which is the y component is mixed with the slurry of the composite hydroxide which is the x component and stirred, and then the mixture slurry is dehydrated and washed and dried at a temperature of 400 ° C. or lower for 5 hours. A binary complex oxide (component A) composed of TiO ₂ —SiO ₂ was obtained. The SO ₄ content in the binary complex oxide was 4.9% by weight. Next, 0.3 kg of monoethanolamine and 3.0 kg of water are mixed,
To this, 0.205 kg of ammonium metavanadate was added and dissolved by heating. This solution and 12.64 kg of the above-mentioned binary complex oxide (component A) were kneaded with a kneader,
Further, a molding aid such as clay or glass fiber was added, and the mixture was kneaded and kneaded, and then extruded 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 muffle furnace to prepare a catalyst IV.

Example 5 As a titanium source, 7.5 kg of titanyl sulfate crystal [TiO ₂ concentration 32% by weight, manufactured by Teika Co., Ltd.] was taken, and water 30.0 was used.
Silica sol [SiO ₂ concentration 20% by weight, trade name “Cataloid S-2
2.1 kg of 0L "catalyst Kasei Kogyo Co., Ltd.] was added and mixed over 15 minutes, 0.17 kg of ammonium paratungstate crystal was further added, and 3N ammonia was added thereto while maintaining the temperature at 60 ° C or lower. 15.2 kg of water 15
TiO ₂ —SiO ₂ —WO ₃ by adding and neutralizing over a period of minutes
Produces complex hydroxide (x component) slurry and further pH
The temperature was maintained at 9.5 to 10 and aged by heating at a temperature of 60 ° C. for 1 hour. Separately, to 32.0 kg of metatitanic acid slurry [TiO ₂ concentration 30% by weight, manufactured by Ishihara Sangyo Co., Ltd.], silica sol [SiO ₂ concentration 20% by weight, trade name "Cataloid S-2"
0L "Catalyst Kasei Kogyo Co., Ltd.] 12.0 kg was added and mixed for 10 minutes, and then 3N ammonia water 1.92 kg
Was added and neutralized, the pH was maintained at 9.5 to 10, and the mixture was aged for 5 hours at a temperature of 60 ° C. to prepare a slurry of the composite hydroxide as the y component. After the slurry of the composite hydroxide of the y component described above is mixed and stirred with the slurry of the composite hydroxide of the y component, the mixture slurry is dehydrated and washed, and dried at a temperature of 400 ° C. or lower for 5 hours to form TiO 2. _2- S
A ternary complex oxide (component A) composed of iO ₂ -WO ₃ was obtained. The SO ₄ content in the binary complex oxide was 4.9% by weight. Next, 0.3 k of monoethanolamine
g and 3.0 kg of water were mixed, and 0.205 kg of ammonium metavanadate was added thereto and dissolved by heating. This solution and the above-mentioned ternary compound oxide (A component) 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 extruded into a honeycomb shape. The moldability was good. Then, the molded product 1
After drying at 10 ° C., it was calcined at 600 ° C. in a muffle furnace to prepare catalyst V.

Example 6 Titanyl sulfate crystal [TiO] as a titanium source_Two32 layers
%, Teika Co., Ltd.] 7.5 kg, water 30.0 k
silica sol [S
iO_TwoConcentration 20% by weight, trade name "Cataloid S-20"
L "Catalyst Kasei Kogyo Co., Ltd.]] 3.0 kg for 15 minutes
Add and mix for 3 days while maintaining the temperature below 60 ° C.
Addition and neutralization of 16.2 kg of ammonia water over 15 minutes
Then TiO _Two-SiO_TwoComplex hydroxide (x component) slurry
Temperature is maintained at a temperature of 60
It was heated and aged for 1 hour at ℃. Separately, metatitanic acid slurry
[TiO_TwoConcentration 30% by weight, manufactured by Ishihara Sangyo Co., Ltd.] 32.
0 kg of silica sol [SiO_TwoProduct with a concentration of 20% by weight
Name "Cataloid S-20L" manufactured by Catalysts & Chemicals Industry Co., Ltd.] 1
Add and mix 1.25 kg over 10 minutes, and then add
Add 0.17 kg of ammonium tungstate crystals
After that, add 1.92 kg of 3N ammonia water and neutralize
And maintain the pH at 9.5 to 10 at 5 ° C at 60 ° C.
Agitate for a while to form a slurry of composite hydroxide, which is the y component.
Prepared. In the slurry of the composite hydroxide which is this y component
Mix and stir the slurry of composite hydroxide which is the above-mentioned x component
After that, the mixture slurry is dehydrated and washed, and the temperature is 400 ° C or higher.
TiO is dried at the lower temperature for 5 hours._Two-SiO_Two-WO_Three
To obtain a ternary complex oxide (component A). The binary system
SO in complex oxides_FourThe content was 4.9% by weight.
Next, 0.3 kg of monoethanolamine and 3.0 k of water
g, and mixed with ammonium metavanadate 0.2
05 kg was added and dissolved by heating. This lysate and the three
12.64 kg of original compound oxide (A component) in a kneader
Knead more and further add molding aids such as clay and glass fiber
In addition, after kneading and kneading, it was extruded into a honeycomb shape.
The sex was good. Then, the molded product is dried at 110 ° C.
After that, the catalyst VI is calcined in a muffle furnace at 600 ° C.
Prepared.

Comparative Example 1 As a titanium source, 43.6 kg of titanyl sulfate crystal [TiO ₂ concentration 32% by weight, manufactured by Teika Co., Ltd.] was taken, and water 17
Silica sol (SiO ₂ concentration 20% by weight, trade name “Cataloid S” in an aqueous solution of titanyl sulfate dissolved and diluted in 4.4 kg.
-20 L "catalyst manufactured by Kasei Kogyo Co., Ltd.)
The mixture was added and mixed over a period of time, and 94.16 kg of 3N ammonia water was added and neutralized over a period of 15 minutes while maintaining the temperature at 60 ° C. or lower, and a TiO ₂ —SiO ₂ composite hydroxide (x component) slurry was added. Was further generated, the pH was maintained at 9.5 to 10, and the mixture was aged by heating at a temperature of 60 ° C. for 1 hour. The obtained TiO ₂ —SiO ₂ composite hydroxide slurry was dehydrated and washed, and then dried at a temperature of 400 ° C. or lower for 5 hours to form TiO ₂ —S.
A binary complex oxide (x component) composed of iO ₂ was obtained. The SO ₄ content in the binary composite oxide was 6.9% by weight. Next, 0.3 kg of monoethanolamine and water 3.
0 kg was mixed, 0.205 kg of ammonium metavanadate was added thereto, and the mixture was heated and dissolved. This solution and 12.64 kg of the above-mentioned binary complex oxide (X component) are kneaded by 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 poor and it was difficult to extrude and mold it into a honeycomb shape. However, a sample for activity measurement was somehow molded, the resulting molded product was dried at 110 ° C., and then calcined at 600 ° C. in a muffle furnace to prepare catalyst VII.

Comparative Example 2 Metatitanic acid slurry [TiO ₂ concentration: 30% by weight, manufactured by Ishihara Sangyo Co., Ltd.] 40.0 kg and silica sol [SiO ₂ concentration: 20% by weight, trade name "Cataloid S-20L" Catalysis Co., Ltd. )] 15.0 kg, and then 30.8 ammonia water 10.8 kg was added to add pH of the slurry.
It was adjusted to 9.5 to obtain a composite hydroxide (y component) slurry. The composite hydroxide slurry had a pH of 9.5 at a temperature of 60 ° C.
After heating and aging for 1 hour while maintaining 10 to 10, this composite hydroxide slurry was dehydrated and washed, and dried at a temperature of 400 ° C. or lower for 5 hours to form a binary composite oxide composed of TiO ₂ —SiO ₂ (Y Component) was obtained. The SO ₄ content in the binary composite oxide was 4.2% by weight. Next, 0.3 kg of monoethanolamine and 3.0 kg of water were mixed, to which 0.205 kg of ammonium metavanadate was added and dissolved by heating. This solution and the above-mentioned binary complex oxide (Y component)
12.64 kg was kneaded with a kneader, and further, clay,
A molding aid such as glass fiber was added, and the mixture was kneaded and kneaded, and then extruded into a honeycomb shape. Then, the molded product is dried at 110 ° C. and then calcined at 600 ° C. in a muffle furnace to obtain catalyst VI.
II was prepared.

Example of Use of Catalyst The denitration performance of the catalysts I to VIII of Examples 1 to 6 and Comparative Examples 1 to 3 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. . Denitrification efficiency measures the concentration of nitrogen oxides NO _X in the gas before and after the catalyst contacted by Kemirumi nitrogen oxide analyzer are those obtained from the following equation.

[Equation 1] Denitration rate (volume%) = {[NO in non-contact gas_X
(Volume ppm) -NO in contact gas_X(Capacity ppm)]
/ NO in non-contact gas_X (Capacity ppm)} × 100 <Test conditions> ・ Catalyst shape: 3 × 3, length: 300 mm, reaction temperature
Degree: 380 ° C., SV = 10,000 hr^-1 ・ Gas composition: NO_X= 180 ppm by volume, NH_Three= 21
6 ppm by volume, O_Two= 2% by volume, SO_Two= 500 capacity p
pm, H_TwoO = 10% by volume, N_Two= Balance Also, SO_XOxidation capacity test is 300m from honeycomb catalyst
The flow-type reactor was filled with the m-thick 3 x 3 pieces.
And SO under the following conditions_ThreeThe conversion rate was measured. SO_ThreeConversion
The rate is SO in the gas before and after contact with the catalyst_TwoInfrared SO concentration
_TwoIt was measured by a gas concentration meter and determined by the following formula.

[Equation 2] SO_ThreeConversion rate (volume%) = {[in non-contact gas
SO_Two(Volume ppm) -SO in contact gas_Two(Capacity pp
m)] / SO in non-contact gas_Two (Capacity ppm)} × 10
0 <Test conditions> ・ Catalyst shape: 3 × 3, length: 300 mm, reaction temperature
Degree: 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 2.

[0038]

[Table 2] (Note) V ₂ O ₅ was 1.0% by weight as an outer percentage.

[0039]

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.

Continuation of front page (51) Int.Cl. ⁷ identification code FI theme code (reference) B01J 37/06 B01D 53/36 102C 37/08 ZAB (72) Inventor Koji Masuda 13- Kitaminato-cho, Wakamatsu-ku, Kitakyushu-shi, Fukuoka 2 Catalyst Kasei Kogyo Co., Ltd. in Wakamatsu Factory (72) Inventor Masaaki Uchida 13-2 Kitaminato-cho, Wakamatsu-ku, Kitakyushu, Fukuoka Prefecture Catalysis Kasei Kogyo Co., Ltd. in Wakamatsu Factory (72) Inventor Kazuhiro Nishii Kawakami town 645-4-301 F-term (reference) 4D048 AA06 AB02 AC04 BA06X BA07X BA23X BA26X BA27X BA41X BA42X BA46X BB02 BC01 4G069 AA02 AA03 AA08 BA21C BA37 BB04A BB04B BB06A BB06B BB08C BB10A BB10B BB10C BC50A BC50B BC50C BC54A BC54B BC54C BC59A BC60A BC60B BC60C BD01C BD05A BD05B BD05C BD06C BD12C BE06C BE08C CA02 CA08 CA13 DA06 EA19 FA01 FA02 FB05 FB09 FB14 FB27 FB30 FB57 FB67 FC02 FC08

Claims (6)

[Claims] 1. A mixed aqueous solution of a soluble titanium compound, a soluble silicon compound and / or a silica sol, or
Complex hydroxide (x component) slurry obtained by adding and neutralizing a basic aqueous solution to a mixed aqueous solution of soluble titanium compound, soluble tungsten compound, soluble silicon compound and / or silica sol, metatitanic acid slurry and soluble silicon compound And / or a composite hydroxide (y component) slurry obtained by adding and neutralizing a basic aqueous solution to a mixed aqueous solution of silica sol or a mixed aqueous solution of metatitanic acid slurry, soluble tungsten compound, soluble silicon compound and / or silica sol. A catalyst for removing nitrogen oxides, containing the obtained composite oxide (component A) and an oxide of at least one metal selected from the group consisting of vanadium, molybdenum and tungsten (component B). 2. The nitrogen oxide removal according to claim 1, wherein the amount of the composite oxide derived from the component x contained in the composite oxide (component A) is in the range of 5 to 30% by weight. Catalyst. 3. The composition of the composite oxide (component A) is 75 to 90% by weight as titanium oxide and 1 as silicon oxide.
0-20% by weight, 0-5% by weight as tungsten oxide
The nitrogen oxide removing catalyst according to claim 1 or 2, characterized in that 4. The nitrogen oxide removal according to claim 1, wherein the composite oxide (component A) contains 1 to 10% by weight of sulfate as SO _{4 based on the} oxide. Catalyst. 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. (1) A mixed aqueous solution of a soluble titanium compound, a soluble silicon compound and / or 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 obtain a slurry of a composite hydroxide (component x). (2) Separately, a metatitanic acid slurry and a soluble silicon compound and / or Add a basic aqueous solution to a mixed aqueous solution of silica sol or a mixed aqueous solution of metatitanic acid slurry, soluble tungsten compound, soluble silicon compound and / or silica sol.
Neutralize to obtain a composite hydroxide (y component) slurry, (3)
The composite hydroxide (a component) or the composite oxide (a component) obtained by mixing the slurry of the composite hydroxide as the x component and the slurry of the composite hydroxide as the y component, and then washing and drying the mixture ( A catalyst for nitrogen oxide removal, characterized in that (A component) carries a precursor (component b) of an oxide of at least one metal selected from the group consisting of vanadium, molybdenum and tungsten, and the mixture is dried and calcined. Manufacturing method.