JP2001321667A - Catalyst for treating waste gas, method for treating waste gas and manufacturing method of catalyst for treating waste gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a denitration catalyst having more excellent removing performance of nitrogen oxides and the remarkably suppressed oxidation performance of sulfur dioxide to sulfur trioxide, a catalyst for treating waste gas, which is excellent as a catalyst suitable for efficiently removing an organic halogen compound such as dioxins in the waste gas, and to provide a treating method of the waste gas using the same and a manufacturing method of the catalyst. SOLUTION: The catalyst for treating the waste gas contains vanadium oxide and a previously prepared binary intimately mixed oxide consisting of titanium and molybdenum and/or a previously prepared ternary homogeneously dense mixed oxide consisting of titanium, silicon and molybdenum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an exhaust gas treatment catalyst, an exhaust gas treatment method, and a method for producing an exhaust gas treatment catalyst. In particular, nitrogen oxides (NOx) in exhaust gas
An exhaust gas treatment catalyst excellent as a catalyst for removing an organic halogen compound for removing toxic organic halogen compounds such as dioxins in exhaust gas, and a method of treating exhaust gas using the same, and The present invention relates to a method for producing the catalyst.

[0002]

2. Description of the Related Art As a method of removing nitrogen oxides from exhaust gas which has been put into practical use at present, harmless nitrogen is removed by catalytically reducing nitrogen oxides in exhaust gas on a denitration catalyst using a reducing agent such as ammonia or urea. The so-called SCR method for selective catalytic reduction to decompose into water and water is common. In recent years, as environmental pollution caused by nitrogen oxides, as represented by acid rain, has become more serious worldwide, it has been required to improve the efficiency of denitration technology. Under these circumstances, a denitration catalyst comprising an oxide of titanium and vanadium and an oxide such as molybdenum and tungsten (JP-B-53-28148), a binary oxide comprising titanium and silicon, vanadium and tungsten A denitration catalyst comprising a metal oxide such as molybdenum or the like (JP-B-57-30532) has been put into practical use and is currently widely used.

[0003] All of these catalysts have excellent nitrogen oxide removal performance, low oxidation performance of sulfur oxides coexisting in exhaust gas, and excellent durability. Is preferred. In addition, dioxins, PCs are contained in exhaust gas generated from incineration facilities that treat industrial and municipal waste.
It contains very small amounts of toxic organic halogen compounds such as B and chlorophenol, and especially dioxins are extremely toxic even in a very small amount, and have serious effects on the human body. ing. Catalytic cracking is one of the most effective techniques, generally
Catalysts containing oxides such as vanadium, tungsten, and molybdenum are used, but they cannot be said to have sufficient performance depending on exhaust gas conditions, and further improvement in catalyst performance is desired.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a denitration catalyst which is more excellent in the removal performance of nitrogen oxides and in which the oxidation performance of sulfur dioxide to sulfur trioxide is extremely suppressed, It is an object of the present invention to provide an exhaust gas treatment catalyst excellent as a catalyst suitable for efficiently removing organic halogen compounds such as dioxins, an exhaust gas treatment method using the same, and a method for producing the catalyst.

[0005]

In order to solve the above-mentioned problems, a catalyst for exhaust gas treatment according to the present invention comprises a vanadium oxide, a binary dense mixed oxide composed of titanium and molybdenum prepared in advance, and / or Alternatively, it contains a ternary close-mixed oxide composed of titanium, silicon and molybdenum prepared in advance. The method for producing an exhaust gas treatment catalyst of the present invention is a method for producing an exhaust gas treatment catalyst containing a titanium oxide, a molybdenum oxide, and a vanadium oxide as a catalyst component, comprising an aqueous solution or slurry containing a titanium compound. And mixing the molybdenum compound and, if necessary, a silicon compound, and then removing water.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The exhaust gas treatment catalyst of the present invention comprises a vanadium oxide, a binary close-mixed oxide composed of titanium and molybdenum prepared in advance, and / or titanium and silicon prepared in advance. And a catalyst containing a ternary dense mixed oxide composed of molybdenum, and the composition of the catalyst when containing a binary dense mixed oxide composed of titanium and molybdenum prepared in advance, the composition of each element is , The oxide of titanium is preferably 55-99.
4 wt%, more preferably 60-90 wt%, molybdenum oxide is preferably 0.5-30 wt%, more preferably 1-25 wt%, and vanadium oxide is preferably 0.1-15 wt%. is there. In addition, the composition of the catalyst in the case of containing a ternary close-mixed oxide composed of titanium, silicon and molybdenum prepared in advance, the weight ratio of each element in terms of oxide, the oxide of titanium is preferably 5 to 5. 98.9
% By weight, more preferably 10 to 90% by weight, the oxide of silicon is preferably 0.5 to 50% by weight, more preferably 5 to 50% by weight, and the molybdenum oxide is preferably 0.5 to 50% by weight.
-30% by weight, more preferably 1-25% by weight, and vanadium oxide is preferably 0.1-15% by weight.

The exhaust gas treatment catalyst of the present invention is a binary close mixed oxide (titanium-molybdenum) composed of titanium and molybdenum.
Preparing and using a molybdenum dense mixed oxide) and / or preparing a ternary close mixed oxide (titanium-silicon-molybdenum mixed oxide) composed of titanium, silicon and molybdenum in advance. It is a feature that it is used. By preparing the titanium-molybdenum dense mixed oxide and / or the titanium-silicon-molybdenum dense mixed oxide in advance, titanium and molybdenum can be dispersed and mixed more densely, and the dispersibility of molybdenum can be improved. In order to improve the activity, the interaction between titanium and molybdenum is strengthened, so that high decomposition activity can be obtained. Therefore, when used as a denitration catalyst, it is considered that the denitration performance is improved while suppressing the oxidation performance of the sulfur oxide. Further, when used as a catalyst for removing organic halogen compounds, it is considered that organic halogen compounds such as dioxins in exhaust gas can be efficiently removed.

In the present invention, the term "close mixed oxide" means
In the X-ray diffraction chart, SiO _TwoAnd MoO_ThreeLight
TiO 2 does not show a distinctive peak_TwoUnique about
Does not show a peak, or even shows
Those that show a broader diffraction peak than the diffraction peak
U. To prepare the exhaust gas treatment catalyst of the present invention, titanium
An aqueous solution or slurry containing the compound and the molybdenum compound
After mixing the product with the silicon compound if necessary, remove the water.
It is preferable to manufacture by a manufacturing method including a removing step.
Remove water from aqueous solutions or slurries containing titanium compounds
(Ie, before titanium oxide crystals form)
Add the molybdenum compound and, if necessary, the silicon compound
By doing so, titanium-molybdenum dense mixed oxide,
Facilitates titanium-silicon-molybdenum dense mixed oxide
Can be obtained.

[0009] Specifically, the following preparation method can be mentioned. (1) A molybdenum compound such as ammonium paramolybdate and molybdic acid is dispersed in water, and ammonia water is added. While stirring the obtained aqueous molybdenum solution, a liquid or aqueous solution of a water-soluble titanium compound such as titanium tetrachloride, titanium sulfate or tetraalkoxytitanium is gradually dropped to obtain a slurry. This is filtered, washed, dried, and then calcined at a high temperature, preferably 300 to 600 ° C., to obtain a titanium-molybdenum dense mixed oxide. In the case of a titanium-silicon-molybdenum densely mixed oxide, silica sol is added in advance to an aqueous solution of molybdenum and ammonia. (2) Aqueous ammonia and water are added to an aqueous solution of a water-soluble titanium compound and hydrolyzed to obtain a titanium hydroxide. An aqueous solution of molybdenum is added to the mixture, and the mixture is kneaded and evaporated to dryness.
Then, bake. In the case of a titanium-silicon-molybdenum dense mixed oxide, a silica sol is added to the titanium hydroxide simultaneously or sequentially with the addition of the aqueous molybdenum solution to the titanium hydroxide. (3) A molybdenum compound (and silica sol in the case of a densely mixed titanium-silicon-molybdenum mixed oxide) is added to the metatitanic acid slurry, and the mixture is kneaded and evaporated to dryness, and then dried at a higher temperature, preferably 300 to 600. ° C,
Bake.

[0010] Among the above preparation methods, the method (1) is more preferable. Titanium-molybdenum dense mixed oxides, or titanium-silicon-molybdenum dense mixed oxides, among the supply sources, inorganic and organic as long as the titanium source is one that generates titanium oxide upon firing. Either compound can be used. For example, an inorganic titanium compound such as titanium tetrachloride or titanium sulfate or an organic titanium compound such as titanium oxalate or tetraisopropyl titanate can be used. As the silicon source, an inorganic silicon compound such as colloidal silica, water glass, fine particle silicon, silicon tetrachloride, and silica gel and an organic silicon compound such as tetraethyl silicate can be appropriately selected and used. The molybdenum source may be any of inorganic and organic compounds as long as it generates molybdenum oxide by firing.For example, an oxide containing molybdenum, a hydroxide, an ammonium salt, a halide, etc. Specific examples thereof include ammonium paramolybdate and molybdic acid.

The titanium-molybdenum dense mixed oxide and the titanium-silicon-molybdenum dense mixed oxide thus obtained may be used alone or as a mixture. Or a mixture with another oxide of titanium, for example, titanium oxide or a densely mixed titanium-silicon oxide. As the supply material of the vanadium oxide, other than the vanadium oxide itself, any material that produces the vanadium oxide by firing may be used.
Both inorganic and organic compounds can be used. For example, a hydroxide containing vanadium, an ammonium salt, an oxalate, a halide, a sulfate, or the like can be used.

The method of adding the vanadium oxide is not particularly limited, and the titanium-molybdenum dense mixed oxide and / or titanium-silicon-
An aqueous solution containing a vanadium source is added to the powder of the molybdenum densely mixed oxide together with an organic or inorganic molding aid generally used when performing this type of molding, and the water is evaporated by heating while mixing and kneading. The extrudable paste is formed into a honeycomb shape by an extruder. After that, a method of drying and firing at a high temperature in the air can be mentioned. Further, as another method, the titanium-molybdenum dense mixed oxide and / or the titanium-silicon-molybdenum dense mixed oxide obtained by the above-described preparation method are previously prepared in a spherical, columnar pellet, or grid-like form. It is also possible to adopt a method of impregnating and supporting an aqueous solution containing a vanadium source after forming and firing into a shape such as a honeycomb. Alternatively, the powder may be prepared by directly kneading a powder of a titanium-molybdenum dense mixed oxide and / or a titanium-silicon-molybdenum dense mixed oxide powder with a vanadium oxide powder.

[0013] The shape of the catalyst is not particularly limited, and it can be used after being formed into a desired shape such as a honeycomb shape, a plate shape, a net shape, a columnar shape, and a cylindrical shape. Further, it may be used by being supported on a carrier having a desired shape such as a honeycomb shape, a plate shape, a net shape, a columnar shape, and a cylindrical shape made of alumina, silica, cordierite, mullite, SiC, titania, stainless steel, or the like. The exhaust gas treating catalyst of the present invention is used for treating various exhaust gases. Although there is no particular limitation on the composition of the exhaust gas, the catalyst of the present invention has excellent decomposition activity of nitrogen oxides discharged from boilers, incinerators, gas turbines, diesel engines and various industrial processes. It is suitably used for treating exhaust gas containing.
Furthermore, these exhaust gases generally contain sulfur dioxide, and when sulfur dioxide is oxidized to sulfur trioxide, problems such as corrosion of equipment occur. It is more preferably used because of its low ability to oxidize sulfur trioxide.

In order to carry out denitration using the catalyst of the present invention, the catalyst of the present invention is treated in the presence of a reducing agent such as ammonia or urea.
Contact with exhaust gas to reduce and remove nitrogen oxides in the exhaust gas. The conditions at this time are not particularly limited, and the reaction can be carried out under conditions generally used for this type of reaction. Specifically, it may be appropriately determined in consideration of the type and properties of the exhaust gas, the required nitrogen oxide decomposition rate, and the like. The space velocity of the exhaust gas when denitration is performed using the catalyst of the present invention is usually 100 to 100000 Hr.
^-1 (STP), preferably 200 to 50,000H
r ⁻¹ (STP). If it is less than 100 Hr ⁻¹ , the processing apparatus becomes too large, resulting in inefficiency.
If it exceeds 00Hr- ¹ , the decomposition efficiency will decrease. Further, the temperature at that time is preferably 100 to 500 ° C.,
More preferably, it is 150 to 400 ° C.

[0015] The catalyst of the present invention is also suitably used for treating an exhaust gas containing an organic halogen compound generated from an incineration facility for treating industrial waste and municipal waste.
In order to treat an organic halogen compound using the catalyst of the present invention, the catalyst of the present invention is brought into contact with exhaust gas to decompose and remove the organic halogen compound in the exhaust gas. The conditions at this time are not particularly limited, and the reaction can be carried out under conditions generally used for this type of reaction. In particular,
It may be appropriately determined in consideration of the type and properties of the exhaust gas, the required decomposition rate of the organic halogen compound, and the like. By adding a reducing agent such as ammonia or urea, denitration can be performed at the same time.

The space velocity of the exhaust gas when treating the organic halogen compound using the catalyst of the present invention is usually
A 100~100000Hr ^-1 (STP), preferably 200~50000Hr ^-1 (STP). 10
Is less than 0Hr ^-1, processor becomes inefficient because too large, whereas the decomposition efficiency is lowered more than 100000Hr ^-1. The temperature at that time is 130 to 500
° C, more preferably 150 to 40 ° C.
0 ° C.

[0017]

EXAMPLES The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited to the following Examples. <Example 1> [Preparation of titanium-molybdenum dense mixed oxide] First, a titanium-molybdenum dense mixed oxide was prepared as follows. Industrial ammonia water (containing 25 wt% NH ₃ ) 12
2.25 kg of molybdic acid powder was added to a mixed solution of 1 kg and 86 liters of water, and the mixture was stirred well to completely dissolve molybdic acid, thereby preparing a homogeneous solution. The solution titanyl sulfate sulfuric acid solution (manufactured by Tayca Corporation, a TiO ₂ 70 g /
Liter, containing 287 g / liter as H ₂ SO ₄ ) 2
57 liters were slowly added dropwise with stirring to produce a precipitate. The coprecipitated slurry was allowed to stand for about 20 hours, washed sufficiently with water, filtered, and dried at 100 ° C. for 1 hour. Further, the powder was fired at 550 ° C. for 4 hours in an air atmosphere, further pulverized using a hammer mill, and classified using a classifier to obtain a powder having an average particle diameter of 10 μm. The composition of the titanium-molybdenum dense mixed oxide prepared in this way has a T
iO ₂ : MoO ₃ = 90: 10 (weight ratio in terms of oxide).

[Addition of vanadium oxide] Next, 1.29 kg of ammonium metavanadate, 1.67 kg of oxalic acid, and 0.4 K of monoethanolamine were added to 8 liters of water.
g were mixed and dissolved to prepare a homogeneous solution. After charging 19 kg of the previously prepared titanium-molybdenum densely mixed oxide powder into a kneader, a vanadium-containing solution was added together with a molding aid, followed by thorough stirring. Further, the mixture was sufficiently mixed with a blender while adding an appropriate amount of water, and then sufficiently kneaded with a continuous kneader, and extruded into a honeycomb shape having an outer shape of 80 mm square, an aperture of 4 mm, a wall thickness of 1 mm, and a length of 500 mm. The obtained molded product was dried at 60 ° C for 1 hour, and then dried at 450 ° C in an air atmosphere.
For 5 hours to obtain the desired catalyst (1). The composition at this time is, by weight ratio, a titanium-molybdenum dense mixed oxide:
V ₂ O ₅ = 95: 5 (TiO ₂ : M in weight ratio in terms of oxide)
oO ₃ : V ₂ O ₅ = 85.5: 9.5: 5).

FIG. 1 shows an X-ray diffraction chart of the catalyst (1).
You. In the X-ray diffraction chart, MoO _ThreeObvious inherent
No peak was observed and TiO_TwoBroad diffraction peak
Is recognized, the titanium and molybdenum
It was confirmed that it was an original dense mixed oxide. <Example 2> [Preparation of titanium-silicon-molybdenum dense mixed oxide]
First, titanium-silicon-molybdenum dense mixed oxide
It was prepared as follows. Silica sol (Snowtex-3
0, Nissan Chemical Industries, SiO_Two30% by weight conversion)
Kg and industrial ammonia water (25 wt% NH_ThreeContained) 1
In a mixed solution of 01.2 Kg and 71 liters of water, add molybdenum
Acid powder 2.25Kg, add well stirring, molybdenum
The acid was completely dissolved to prepare a homogeneous solution. In this solution
Titanyl sulfate solution (manufactured by Teica, TiO_TwoAs 7
0 g / liter, H_TwoSO_FourIncluding 287 g / l
Yes) 214 liters were slowly added dropwise with stirring.
Generated. Let this coprecipitated slurry stand for about 20 hours.
After that, wash thoroughly with water, filter, and at 100 ° C for 1 hour.
While drying. Further, at 550 ° C for 4 hours in an air atmosphere
Calcination, further crushing using a hammer mill, and using a classifier
After classification, a powder having an average particle diameter of 10 μm was obtained. Like this
Titanium-silicon-molybdenum dense mixed oxide prepared by
Is composed of TiO_Two: SiO_Two: MoO_Three= 75: 15:
10 (weight ratio in terms of oxide).

[Addition of Vanadium Oxide]
In the step of adding the sodium oxide, titanium-molybdenum
In place of dense mixed oxides, the chips prepared as above
Except using tan-silicon-molybdenum dense mixed oxide
Was prepared by adding vanadium oxide in the same preparation method as in Example 1.
And catalyst (2) was prepared. The composition at this time is the weight ratio
And titanium-silicon-molybdenum dense mixed oxide: V_Two
O_Five= 95: 5 (weight ratio in terms of oxide, TiO_Two: SiO
_Two: MoO_Three: V_TwoO_Five= 71.25: 14.25: 9.
5: 5). The figure shows the X-ray diffraction chart of catalyst (2).
It is shown in FIG. In the X-ray diffraction chart, SiO _TwoAnd Mo
O_ThreeIs not observed, and TiO_TwoBu
Since a heavy diffraction peak is observed, titanium and ke
It is a ternary dense mixed oxide composed of iodine and molybdenum
It was confirmed that.

<Example 3> [Preparation of titanium-silicon dense mixed oxide] A titanium-silicon dense mixed oxide was prepared as follows. 10 kg of silica sol (Snowtex-30, manufactured by Nissan Chemical Industries, containing 30 wt% in terms of SiO ₂ ) and industrial ammonia water (25
104 Kg (containing wt% NH ₃ ) and 73 L of water were mixed to prepare a homogeneous solution. To this solution was added a titanyl sulfate solution (manufactured by Teica, 70 g / liter as TiO ₂ ,
242.8 liters (containing 287 g / liter as H ₂ SO ₄ ) were gradually added dropwise with stirring to form a precipitate. The coprecipitated slurry was allowed to stand for about 20 hours, washed sufficiently with water, filtered, and dried at 100 ° C. for 1 hour. Furthermore, baking at 550 ° C. for 4 hours in an air atmosphere,
The powder was further ground using a hammer mill and classified with a classifier to obtain a powder having an average particle diameter of 10 μm. The composition of the titanium-silicon dense mixed oxide prepared in this manner is TiO ₂ : S
iO ₂ = 85: 15 (weight ratio in terms of oxide). X-ray diffraction of a titanium-silicon dense mixed oxide shows that TiO ₂
, But no distinctive peak of SiO ₂ was observed.

[Addition of Vanadium Oxide] In the step of adding vanadium oxide in Example 1, instead of 19 kg of the titanium-molybdenum dense mixed oxide, the titanium-molybdenum dense mixed oxide 9 used in Example 1 was used. A catalyst (3) was prepared by adding vanadium oxide by the same preparation method as in Example 1 except that 0.5 kg and 9.5 kg of the titanium-silicon dense mixed oxide prepared above were mixed and used. . The composition at this time was, in terms of weight ratio, titanium-molybdenum dense mixed oxide: titanium-silicon dense mixed oxide: V ₂ O ₅ = 47.
5: 47.5: 5 (TiO ₂ : S in terms of oxide weight ratio)
iO ₂ : MoO ₃ : V ₂ O ₅ = 83.1: 7.1: 4.8:
5).

Example 4 In the step of adding vanadium oxide of Example 3, the titanium-silicon-molybdenum homogeneous oxide used in Example 2 was used instead of the titanium-molybdenum dense mixed oxide used in Example 1. A catalyst (4) was prepared by adding vanadium oxide by the same preparation method as in Example 3 except that a closely mixed oxide was used. The composition at this time was, in terms of weight ratio, titanium-silicon-molybdenum dense mixed oxide: titanium-silicon dense mixed oxide: V ₂ O ₅ = 47.5: 47.
5: 5 (weight ratio in terms of oxide: TiO ₂ : SiO ₂ : Mo
O ₃ : V ₂ O ₅ = 76: 14.25: 4.75: 5).

<Example 5> In the step of adding vanadium oxide in Example 4, a commercially available titanium oxide powder (DT) was used instead of the titanium-silicon dense mixed oxide used in Example 3.
-51 (trade name), manufactured by Millennium)
Catalyst (5) was prepared in the same manner as in Example 4. The composition at this time is a titanium-silicon-molybdenum dense mixed oxide: titanium oxide: V ₂ O ₅ = 70: 25: 5 (weight ratio in terms of oxide, TiO ₂ : SiO ₂ : MoO _3). : V ₂ O
₅ = 77.5: 10.5: 7: 5). <Comparative Example 1> A solution prepared by dissolving 1.29 Kg of ammonium metavanadate and 1.68 Kg of oxalic acid in 5 L of water was added to 17 Kg of commercially available titanium oxide powder (DT-51 (trade name), manufactured by Millennium Co., Ltd.). 2.46 kg of ammonium molybdate and 1.1 kg of monoethanolamine
Was dissolved in 3 liters of water, mixed well, and kneaded with a kneader.
m square, aperture 4.0 mm, wall thickness 1.0 mm, length 500
mm was formed into a honeycomb shape. Next, after drying at 80 ° C. for 1 hour, it was calcined at 450 ° C. for 5 hours in an air atmosphere to obtain a catalyst (6).

The composition of this catalyst is TiO_Two: MoO_Three: V
_TwoO_Five= 90: 10: 5 (weight% in terms of oxide).
FIG. 3 shows an X-ray diffraction chart of the catalyst (6). X-ray diffraction
In the chart, MoO _ThreeObvious unique peak
The binary system composed of titanium and molybdenum
It was confirmed that the oxide was not a close mixed oxide. <Comparative Example 2> Instead of commercially available titanium oxide powder,
The reason why the titanium-silicon dense mixed oxide prepared in 3 was used
Except for the above, a catalyst (7) was prepared in the same manner as in Comparative Example 1.

The composition of this catalyst is TiO ₂ : SiO ₂ : M
oO ₃ : V ₂ O ₅ = 72.25: 12.75: 10: 5
(% By weight in terms of oxide). It was measured for NOx removal performance test and SO ₂ oxidation rate under the following conditions using a <Example 6> catalyst obtained in Examples 1 to 5 and Comparative Examples 1 and 2 (1) to (7). Process gas composition NOx: 200 ppm, SO ₂ : 1000 ppm, N
_{H 3: 200ppm, O 2:} 10%, H 2 O: 15%,
N ₂ : balance gas temperature 250 ° C. space velocity: 10000 Hr ^{−1 The} denitration rate and SO ₂ oxidation rate were determined according to the following equations.

DeNOx rate (%) = {(NOx concentration at reactor inlet)-(NOx concentration at reactor outlet)} (NO at reactor inlet
x concentration) × 100 SO ₂ oxidation rate (%) = (reactor outlet SO ₃ concentration) ÷ (reactor inlet SO ₂ concentration) × 100 The obtained denitration rate and SO ₂ oxidation rate are shown in Table 1.

[0028]

[Table 1]

<Example 7> Using the catalysts (1) and (2) obtained in Examples 1 and 2, the gas temperature was set to 150 to 400 ° C.
A denitration performance test and measurement of an SO ₂ oxidation rate were performed in the same manner as in Example 6 except that the above conditions were changed. The resulting denitration rate and SO ₂ oxidation ratio shown in Table 2.

[0030]

[Table 2]

Example 8 Examples 1 to 5 and Comparative Example 1
An organic chlorine compound decomposition test was performed using the catalysts (1) to (7) prepared in the above (2) to (2). Reaction was carried out under the following conditions using chlorotoluene (hereinafter abbreviated as CT) as an organic chlorine compound to be treated. Processing gas composition CT: 30 ppm, O ₂ : 10%, H ₂ O: 15%,
N ₂ : Balance Gas temperature: 160 ° C. Space velocity (SV): 1600 Hr ^{−1 The} CT decomposition rate, that is, the CT removal rate was determined according to the following equation.

CT decomposition rate (%) = [(CT concentration at reactor inlet)
− (Reactor outlet CT concentration)] / (Reactor inlet CT concentration) × 1
Table 3 shows the obtained CT decomposition rates.

[0033]

[Table 3]

[0034]

According to the present invention, titanium and molybdenum can be more densely dispersed and mixed, and the dispersibility of molybdenum is improved, so that the interaction between titanium and molybdenum is strengthened, so that a high decomposition activity is obtained. Will be able to Therefore, when used as a denitration catalyst, the denitration performance is improved while suppressing the oxidation performance of the sulfur oxide. When used as a catalyst for removing organic halogen compounds, organic halogen compounds such as dioxins in exhaust gas can be efficiently removed.

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction chart of a catalyst (1) prepared in Example 1.

FIG. 2 is an X-ray diffraction chart of a catalyst (2) prepared in Example 2.

FIG. 3 is an X-ray diffraction chart of a catalyst (6) prepared in Comparative Example 1.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Noboru Sugishima No. 992, Nishioki, Okihama-shi, Abashiri-ku, Himeji-shi BA02A BA02B BA02C BA04A BA04B BA04C BB04A BB06A BB06B BC54A BC54B BC54C BC59A BC59B BC59C CA02 CA08 CA13 CA19 DA06 EA01Y EA02Y EC25 FB05 FB06 FB09

Claims (4)

[Claims] 1. Binary dense mixed oxide composed of vanadium oxide and titanium and molybdenum prepared in advance, and / or ternary dense mixed oxide composed of titanium, silicon and molybdenum prepared in advance. An exhaust gas treatment catalyst containing a substance. 2. A method for treating exhaust gas, comprising treating an exhaust gas containing nitrogen oxides using the catalyst according to claim 1. 3. An exhaust gas treatment method comprising treating an exhaust gas containing an organic halogen compound using the catalyst according to claim 1. 4. A method for producing an exhaust gas treatment catalyst containing a titanium oxide, a molybdenum oxide and a vanadium oxide as a catalyst component, comprising an aqueous solution or slurry containing a titanium compound, a molybdenum compound and optionally A process for removing water after mixing with a silicon compound by mixing with a silicon compound.