JP6906420B2 - Manufacturing method of inorganic composite oxide and exhaust gas treatment method using this - Google Patents

Description

The present invention relates to a method for producing an inorganic composite oxide composed of titanium, silicon, tungsten, vanadium and molybdenum, and a method for removing nitrogen oxides and organic halogen compounds in exhaust gas using the inorganic oxide as a catalyst.

Nitrogen oxides (NOx) are harmful substances to the human body and are causative substances of acid rain and photochemical smog. As a countermeasure, nitrogen oxides in exhaust gas are catalyzed by using a reducing agent such as ammonia or urea. The selective catalytic reduction method (SCR method), in which the above is catalytically reduced and decomposed into nitrogen and water, is generally used. In addition, organic halogen compounds typified by dioxins are also harmful substances that have a serious effect on the human body, and catalytic decomposition and removal are also widely used in their treatment. In particular, it is often necessary to remove both nitrogen oxides and organic halogen compounds in the exhaust gas emitted from waste treatment facilities such as municipal waste incinerators.

Examples of the exhaust gas treatment catalyst used for such applications include catalysts containing titanium oxide, vanadium oxide and tungsten oxide (Patent Documents 1 and 2), or titanium oxide, vanadium oxide and molybdenum oxide. (Patent Documents 3 and 4) are disclosed.

On the other hand, in recent years, _{it has been desired to lower the exhaust gas treatment temperature from the viewpoint of reducing CO 2} emissions associated with reheating the exhaust gas. For example, the treatment of exhaust gas from an urban waste incinerator is excellent even in a low temperature range of less than 200 ° C. There is a demand for a catalyst having excellent removal performance and durability. In this regard, as a catalyst having further improved performance and durability, a catalyst containing a titanium-based oxide, a vanadium oxide, and a sulfate of a metal such as copper or cobalt has been proposed (Patent Document 5).

Japanese Unexamined Patent Publication No. 10-235191 Japanese Unexamined Patent Publication No. 2014-061476 Japanese Unexamined Patent Publication No. 2001-062292 Japanese Unexamined Patent Publication No. 2001-276617 Japanese Unexamined Patent Publication No. 2006-320803

In response to the recent demand for higher efficiency of exhaust gas treatment, it is desired to develop a catalyst having further excellent treatment performance. The present invention has been made under such circumstances, and a method for producing an inorganic composite oxide capable of treating nitrogen oxides and organic halogen compounds more efficiently than in the past, and the inorganic composite. It is an object of the present invention to provide a method for treating exhaust gas using an oxide.

As a result of diligent studies to solve the above problems, the present inventor has found that the inorganic composite oxide produced by the method shown below is effective. That is, the method for producing an inorganic composite oxide of the present invention includes a supporting step of supporting a vanadium compound and a molybdenum compound on a composite oxide or a mixed oxide containing titanium and silicon, tungsten and / or vanadium, and firing. A method for producing an inorganic composite oxide having a step, which comprises a vanadium compound, a molybdenum compound, and a compound containing a nitrogen atom having a structure as a blended base in the supporting step, and the nitrogen atom and the molybdenum atom. It is characterized in that an aqueous solution having a molar ratio (N / Mo) of 4.5 to 6.5 is used. Further, it is an exhaust gas treatment method using the composite oxide as a catalyst.

By using the present invention, harmful substances such as nitrogen oxides and organic halogen compounds can be efficiently removed from the exhaust gas.

The present invention includes a supporting step of supporting a vanadium compound and a molybdenum compound on an oxide containing titanium and silicon and tungsten and / or vanadium (hereinafter referred to as a titanium-based oxide), and a firing step. A method for producing an inorganic composite oxide, which comprises a vanadium compound, a molybdenum compound, and a compound containing a nitrogen atom having a structure as a blended base in the supporting step, and the molar ratio of the nitrogen atom to the molybdenum atom ( It is characterized by using an aqueous solution having an N / Mo) of 4.5 to 6.5.

The titanium-based oxide is an oxide containing titanium and silicon, and further containing tungsten and / or vanadium. However, it includes not only a form in which all the elements form a composite oxide, but also a form in which an oxide containing only some elements and an oxide containing other elements are mixed.

Hereinafter, the method for producing the inorganic composite oxide of the present invention will be described in order.

1. 1. Titanium oxide 1-1. Raw Materials The raw materials used for the preparation of the titanium oxide of the present invention are as follows.

As the titanium raw material, titanyl sulfate, titanium tetrachloride, metatitanic acid, tetraisopropyl titanate and the like can be used. Titanyl sulfate and metatitanic acid are preferable, and titanyl sulfate is more preferable.

As the silicon raw material, silica sol, water glass, silicon tetrachloride, tetraethoxysilane and the like can be used. A silica sol or tetraethoxysilane is preferable, and a silica sol is more preferable.

As the tungsten raw material, ammonium paratungstate, ammonium metatungstate, tungstic acid and the like can be used. Ammonium paratungstate and ammonium metatungstate are preferred, and ammonium paratungstate is more preferred.

As the vanadium raw material, ammonium metavanadate, vanadium pentoxide, vanadium trioxide and the like can be used. Ammonium metavanadate and vanadium pentoxide are preferable, and ammonium metavanadate is more preferable.

1-2. Preparation method Examples of the method for preparing the titanium-based oxide performed using the raw materials described in 1-1 include a sol-gel method, a hydrothermal synthesis, a coprecipitation method, a deposition method, a kneading method, a precipitation precipitation method, and each raw material. Can be appropriately selected from known preparation methods such as a method of mixing and firing. A sol-gel method, a coprecipitation method, a kneading method, a method of mixing and firing each raw material is preferable, and a coprecipitation method is more preferable.

As a specific method, examples described in JP-A-2016-64358, JP-A-2014-61476, and the like may be referred to.

2. Aqueous liquid used in the loading process 2-1. Vanadium compound As the vanadium compound used for preparing an aqueous solution, oxides, hydroxides, inorganic salts, organic salts and the like are used, and for example, ammonium metavanadate is preferably used.

When the inorganic composite oxide of the present invention is used as a catalyst for treating exhaust gas containing nitrogen oxides, the content of vanadium oxide in the inorganic composite oxide has a great influence on the removal performance of nitrogen oxides.

Therefore, the amount of the vanadium compound used in the preparation of the aqueous solution is preferably 1 to 20% by mass in terms of _{vanadium pentoxide (V 2} O _{5) with respect to the total mass of the inorganic composite oxide, and more preferably 3.} It is ~ 15% by mass, more preferably 5-10% by mass. This is because if the content of vanadium oxide is less than 1% by mass, sufficient removal performance cannot be obtained, and if it is contained in a large amount exceeding 20% by mass, the performance may be deteriorated due to the sintering of metal species. If vanadium is contained in the titanium-based oxide, the amount thereof is taken into consideration when adjusting.

2-2. Molybdenum compound As the molybdenum compound used for preparing the aqueous solution, oxides, hydroxides, inorganic salts, organic salts and the like are used, and for example, molybdic acid, ammonium paramolybdate and molybdate oxide are preferably used.

When the inorganic composite oxide of the present invention is used as a catalyst for exhaust gas treatment, the content of the molybdenum oxide in the inorganic composite oxide has a great influence on the removal performance and durability.

Therefore, the amount of the molybdenum compound used in the preparation of the aqueous solution is preferably 2 to 10% by mass, more preferably 3 to 8 in terms of _{molybdenum trioxide (MoO 3) with respect to the total mass of the inorganic composite oxide.} It is by mass, more preferably 4 to 6% by mass. This is because if the content of the molybdenum oxide is less than 2% by mass, sufficient durability cannot be obtained, and if the content of the molybdenum oxide exceeds 10% by mass, the removal performance may deteriorate. If molybdenum is contained in the titanium-based oxide, the amount of molybdenum is taken into consideration when adjusting.

2-3. Compound containing a nitrogen atom having a structure that becomes a blended base The compound containing a nitrogen atom having a structure that becomes a blended base used in the present invention (hereinafter, may be referred to as a basic nitrogen compound) is ammonia or mono. not only compounds which protons are not added, such as ethanolamine, ammonium ions and monoethanolamine cation _{(HO-CH 2 -CH 2 -NH} 3 +) nitrogen atom having a structure comprising a Bronsted base so like ( It also includes a form in which a proton is added to a basic nitrogen atom (hereinafter, may be referred to as a basic nitrogen atom) (hereinafter, may be referred to as a proton-added nitrogen compound).

The number of moles of the basic nitrogen atom in the present invention is not the number of moles of the basic nitrogen compound but the number of moles of the nitrogen atom. For example, in the case of a compound containing two basic nitrogen atoms such as ethylenediamine, the number of moles of the basic nitrogen atom is double the number of moles of ethylenediamine. When the vanadium compound or molybdenum compound used in the aqueous solution is an ammonium salt, ammonia (ammonium cation) contained therein is also included in the number of moles of the basic nitrogen atom. When a plurality of basic nitrogen compounds are contained, the number of moles of each basic nitrogen atom is totaled.

The basic nitrogen compound is preferably a nitrogen atom-containing inorganic compound such as ammonia, ammonium nitrate or ammonium carbonate, an organic compound having 1st to 3rd grade nitrogen atoms such as ethanolamine or pyridine, and the basicity of these basic nitrogen compounds. It is at least one selected from proton-added nitrogen compounds in which a proton is added to a nitrogen atom, and more preferably selected from ammonia, ammonium cation, monoethanolamine, monoethanolamine cation, ethylamine, ethylammonium cation, pyridine, and pyridinium cation. It is a form in which at least one selected from ammonia and ammonium cation and at least one selected from monoethanolamine and monoethanolamine cation are used in combination.

2-4. Molar ratio of nitrogen atom to molybdenum atom (N / Mo)
The molar ratio of nitrogen atom to molybdenum atom (hereinafter, may be referred to as N / Mo ratio) in the present invention is in the range of 4.5 to 6.5, preferably 5.0 to 6.5. It is preferably in the range of 5.5 to 6.5. If the molar ratio of base to molybdenum in the aqueous liquid is less than 4.5 or more than 6.5, the performance of the exhaust gas treatment catalyst may be insufficient.

2-5. Aqueous solution The aqueous solution used in the present invention is a solution or slurry containing the vanadium compound, the molybdenum compound, and the basic nitrogen compound in water. A solution or slurry containing only oxalic acid or oxalate ion, more preferably the vanadium compound, the molybdenum compound, the basic nitrogen compound, water, oxalic acid or oxalate ion is more preferable. Is a solution containing only the vanadium compound, the molybdenum compound, the basic nitrogen compound, water, oxalic acid or oxalate ion.

The oxalic acid contained in the aqueous solution may be not only oxalic acid and / or oxalate ion, but also an oxalic acid compound such as ammonium oxalate or vanadyl oxalate. The total amount is preferably 0.9 to 10 mol, more preferably 1 to 7 mol, still more preferably 1.5 to 5 mol, based on 1 mol of vanadium atom in the aqueous liquid.

The amount of water contained in the aqueous solution is preferably 1 to 10 with respect to the mass of the vanadium compound, and more preferably 1.5 to 5. If it is 1 or less, the vanadium oxide or molybdenum oxide cannot be uniformly supported because an aqueous liquid is locally present at the time of supporting, and if it is 10 or more, it becomes a slurry when the carrier is impregnated. This is not preferable because it becomes difficult to handle when forming the inorganic composite oxide in the subsequent step.

The amount of water outside the above range may be contained at the time of preparing the aqueous solution as long as it is appropriately adjusted when used in the supporting step.

The temperature of the aqueous liquid is preferably 0 ° C. to 90 ° C., more preferably 10 ° C. to 70 ° C., and even more preferably 20 ° C. to 60 ° C. At 0 ° C. or lower, it is difficult to obtain a uniform solution, and at 90 ° C. or higher, water and basic nitrogen compounds volatilize and the composition of the aqueous solution is not stable, which is not preferable.

3. 3. Method for producing inorganic composite oxide 3-1. Supporting Step As a method for preparing an aqueous liquid containing a vanadium compound and a molybdenum compound used in the supporting step, any of the following (a) to (c) is preferable. The additional basic nitrogen compound in the following method does not include a basic nitrogen compound derived from another raw material compound such as ammonium metavanadate and ammonium molybdate, and adjusts the N / Mo ratio of the obtained aqueous solution. It is a basic nitrogen compound added for the purpose.

(A) Method of mixing a solution containing a vanadium compound and a solution containing an additional basic nitrogen compound and a molybdenum compound in a solution containing oxalic acid Specifically, in a solution or slurry of oxalic acid and water. This is a method of adding a solution or slurry of a vanadium compound and water, and a solution or slurry of a molybdenum compound and an additional basic nitrogen compound and water in this order.
(B) Method of mixing a solution containing a vanadium compound, an additional basic nitrogen compound and a molybdenum compound in oxalic acid and an additional basic nitrogen compound Specifically, oxalic acid, an additional basic nitrogen compound and water This is a method of adding a vanadium compound or a solution containing a vanadium compound, a solution of a molybdenum compound, an additional basic nitrogen compound, and water, or a slurry in this order to the solution or slurry of the above.
(C) Method of mixing a liquid containing a vanadium compound and a molybdenum compound with oxalic acid and an additional basic nitrogen compound Specifically, a vanadium compound is added to a solution or slurry of oxalic acid, an additional basic nitrogen compound and water. It is a method of adding a molybdenum compound or a liquid containing them.

In the method for preparing the aqueous liquids (a) to (c), (b) is preferable in that a homogeneous solution or slurry can be prepared in a shorter time.

The supporting method in this step can be appropriately selected from known methods as long as the aqueous liquid obtained by the method for preparing the aqueous liquid and the composite oxide can be sufficiently mixed. When controlling the pore volume of the obtained inorganic composite oxide, a kneading method in which the aqueous liquid and the composite oxide are mixed with a kneader or the like is preferable.

3-2. Firing step After the supporting step, the inorganic composite oxide is obtained by heating at a predetermined temperature and time.

The maximum temperature in this step is referred to as a firing temperature, which is preferably 300 ° C. to 600 ° C., more preferably 350 ° C. to 550 ° C., and even more preferably 400 ° C. to 500 ° C. At 300 ° C. or lower, the formation of the inorganic composite oxide may be insufficient, and at 600 ° C. or higher, vanadium, molybdenum, etc. may volatilize, which is not preferable.

The time during which the heating is performed in the predetermined temperature range is referred to as the firing time. Therefore, it does not always match the time held at the firing temperature. If the firing temperature is low, it can be adjusted by lengthening the firing time. However, in general, it is preferably 3 hours to 7 hours, and more preferably 4 hours to 6 hours.

The atmosphere gas in this step preferably contains an oxidizing gas component. Oxygen is preferable as the oxidizing gas component, and air is a typical atmospheric gas. When the basic nitrogen compound is an organic compound, the first half of the firing step may be carried out in an oxygen-free or low-oxygen atmosphere, and the latter half may be carried out in a high-oxygen atmosphere such as air.

From the viewpoint of uniform firing, it is preferable that the atmospheric gas is flowing. The degree of flow may be appropriately set from the amount and arrangement of the obtained inorganic composite oxide, the internal volume of the firing apparatus, and the like. As a guide, the temperature difference in the firing apparatus can be raised, and the temperature may be adjusted to be within 30 ° C., preferably within 20 ° C., more preferably within 15 ° C.

In addition, in order to supplement the oxidizing gas consumed during firing and to discharge the gas generated by the decomposition and evaporation of the compound used in the aqueous liquid, the intake air into the firing device and the exhaust gas to the outside of the device are exhausted. It may be done continuously.

3-3. Other Steps The method for producing an inorganic composite oxide of the present invention may include a molding step, a drying step, and the like in addition to the supporting step and the firing step. When the molding step and the drying step are performed, the following embodiments (1) to (3) are preferable. The main difference between the drying step and the firing step is the temperature, and it is possible to continue without distinguishing between them.

(1) Form in which a molding step, a drying step, and a firing step are performed in this order after the supporting step This is a method of molding into a predetermined shape, drying, and firing after the supporting step.

(2) Form in which a drying step, a firing step, a slurrying step, a molding step, a drying step, and a firing step are performed in this order after the supporting step. This is a method of molding into a predetermined shape, drying and firing again.

(3) Form in which the drying step, the firing step, the slurrying step, the carrier coating step, the drying step, and the firing step are performed in this order after the supporting step. This is a method in which a slurry is added to a predetermined carrier, and the mixture is dried and fired again.

In the molding step, known methods such as extrusion molding, tableting molding, and rolling granulation can be performed. Further, the molded shape can be selected from a saddle shape, a pellet shape, a sphere shape, a honeycomb shape, and the like according to the purpose.

Further, the shape of the carrier used in the carrier coating step may be appropriately selected from saddle shape, pellet shape, sphere shape, honeycomb shape and the like according to the purpose.

When used as a catalyst for exhaust gas treatment, a honeycomb shape is preferable because the pressure loss of the apparatus is reduced.

4. Exhaust gas treatment method The inorganic composite oxide obtained by the production method of the present invention is suitably used as an exhaust gas treatment catalyst. In particular, it is suitable for exhaust gas treatment containing nitrogen oxides (hereinafter, may be referred to as NOx) and / or organic halogen compounds.

4-1. The specific surface area of the inorganic mixed oxide of the catalyst properties present invention may in the range of 50 to 200 m ² / g, more preferably 60~150m ² / g, more preferably in the range of 70~120m ² / g Is good. If the specific surface area of the inorganic composite oxide is too low, sufficient catalytic performance cannot be obtained, and sintering of the supported metal species is likely to occur. If the specific surface area is too high, the catalytic performance does not improve so much, but the accumulation of toxic substances This is because the amount may increase and the performance degradation may increase.

The pore volume of the inorganic composite oxide of the present invention is preferably such that the total pore volume is in the range of 0.25 to 0.70 mL / g, more preferably 0.25 to 0.60 mL / g. More preferably, it is in the range of 0.30 to 0.50 mL / g. If the pore volume of the inorganic composite oxide is too small, sufficient catalytic performance cannot be obtained, and if it is too large, the catalytic performance does not improve so much, but there are adverse effects such as a decrease in mechanical strength and hindrance to handling. It is not preferable because it may occur.

4-2. Exhaust gas treatment temperature The treatment temperature of the exhaust gas of the present invention is preferably in the range of 150 to 400 ° C., preferably 150 to 300 ° C., more preferably 160 to 250 ° C., and even more preferably 160 to 190 ° C. If the treatment temperature of the exhaust gas is less than 150 ° C, sufficient removal efficiency of NOx and organic halogen compounds cannot be obtained, and if it exceeds 400 ° C, the catalytic performance may be deteriorated due to the scattering of molybdenum and adverse effects on the wake equipment may be caused. Is.

4-3. Exhaust gas composition When the exhaust gas to be treated by the catalyst according to the present invention contains nitrogen oxides and / or organic halogen compounds, the NOx concentration in the exhaust gas is preferably 5 to 1000 ppm (capacity standard), more preferably. Is preferably in the range of 10 to 500 ppm, more preferably 20 to 300 ppm. Sufficient NOx removal performance is not exhibited when the NOx concentration in the exhaust gas is less than 5 ppm, while when it exceeds 1000 ppm, sulfur oxides contained in the exhaust gas form compounds such as ammonium sulfate on the catalyst surface and inside the equipment piping. This is because it is not preferable because it accumulates in such as.

The concentration of the organic halogen compound in the exhaust gas is preferably 0.1 ppt to 3000 ppm (volume basis), more preferably 0.5 ppt to 1000 ppm, and further preferably 1 ppt to 500 ppm. This is because if the concentration of the organic halogen compound in the exhaust gas is less than 0.1 ppt, sufficient decomposition performance is not exhibited, while if it exceeds 3000 ppm, heat generation due to the reaction becomes large and the catalyst may be thermally damaged.

Other components contained in the exhaust gas include oxygen, water, and sulfur oxides (hereinafter, may be referred to as SOx). For example, it is preferably used under the condition that oxygen is present in the exhaust gas, and the oxygen concentration in this case is preferably in the range of 0.1 to 50% by volume, more preferably 0.3 to 20% by volume. More preferably, it is in the range of 0.5 to 16% by volume. If the oxygen concentration is less than 0.1% by volume, the removal efficiency is lowered, and if it exceeds 50% by volume, SO ₂ oxidation, which is a side reaction, is promoted, which is not preferable. When the exhaust gas contains water, its concentration is preferably 50% by volume or less, more preferably 40% by volume or less, and further preferably 30% by volume or less. This is because if the water concentration in the exhaust gas exceeds 50% by volume, the removal efficiency is lowered and, in some cases, the performance is significantly lowered.

The catalyst according to the present invention is preferably used even when SOx is contained in the exhaust gas, but the SOx concentration is 0.1 to 2000 ppm (volume basis), preferably 0.2 to 500 ppm, more preferably. Is preferably in the range of 0.5 to 100 ppm, more preferably 1 to 50 ppm. The effect of the present invention is exhibited in the treatment of exhaust gas having an SOx concentration of 0.1 ppm or more. On the other hand, if the SOx concentration in the exhaust gas exceeds 2000 ppm, the performance deterioration due to SOx becomes large, which is not preferable.

When treating the exhaust gas, ammonia or urea (also referred to as ammonia or the like) can be added to the exhaust gas. This is especially effective when the exhaust gas contains nitrogen oxides. The amount of ammonia or the like added is 0.2 to 20 mol, preferably 0.5 to 1.0 mol, in terms of ammonia (1/2 mol in the case of urea) with respect to 1 mol of nitrogen oxide (NOx equivalent). Is.

When an organic halogen compound is contained in the exhaust gas, it is not necessary to add ammonia or the like, but the addition of ammonia or the like does not impair the effect of the catalyst according to the present invention.

4-4. Exhaust gas amount also space velocity during the exhaust gas treatment of the present invention, 100~50,000h ^-1 (STP), preferably 200~10,000h ^-1 (STP), more preferably 500~5,000h ^-1 ( It should be in the range of STP). Pressure loss of sufficient removal efficiency can not be ^obtained, it is less than ^100h -1 (STP) but removal efficiency does not change greatly the exhaust gas treatment apparatus of the space velocity exceeds 50,000h ^-1 (STP) NOx and organic halogen compounds This is because the device itself becomes large and inefficient. Further, the linear velocity of the gas passing through the catalyst layer in the exhaust gas treatment of the present invention is 0.1 to 10 m / s (STP), preferably 0.5 to 7 m / s (STP), more preferably 0.7 to 0.7 to It should be in the range of 4 m / s (STP). If the linear velocity is less than 0.1 m / s (NTP), sufficient removal efficiency cannot be obtained, and if it exceeds 10 m / s (STP), the removal efficiency does not increase, but the pressure loss of the exhaust gas treatment device increases. be.

(Example 1)
<Preparation of titanium oxide>
In 90 L of water, 14.4 kg of ammonium paratungstate and 6.2 kg of monoethanolamine were heated to 65 ° C. and mixed to obtain a uniform solution. Silica sol (Snowtex -30 (product name), manufactured by Nissan Chemical Industries, Ltd., SiO ₂ in terms of 30 wt% containing) and 105 kg, and industrial aqueous ammonia (20 wt% NH ₃ containing) 801Kg, water 2950L, and tungsten-containing solution 8500 L of titanyl sulfate (manufactured by Teika Co., Ltd., containing 70 g / L as _{TiO 2 and 280 g / L as H 2} SO ₄ ) was gradually added dropwise to the mixed solution of Ammonia to form a precipitate, and then an appropriate amount of ammonia. Water was added to adjust the pH to 7.

The obtained coprecipitated slurry was allowed to stand for about 40 hours, washed thoroughly with water, filtered, and dried at 100 ° C. for 1 hour. Further, it may be calcined at 500 ° C. for 5 hours in an air atmosphere, further crushed using a hammer mill, classified by a classifier, and referred to as a titanium oxide (hereinafter referred to as Ti—Si—W composite oxide powder). There is) got. The composition of the Ti—Si—W ternary oxide powder thus prepared was TiO ₂ : SiO ₂ : WO ₃ = 93: 5: 2 (mass ratio).

<Preparation of aqueous liquid>
A vanadium-containing solution in which 71.3 g of ammonium metavanadate, 128.3 g of oxalate and 38.5 g of monoethanolamine were mixed and dissolved in 90 mL of water, and 36.8 g of monoethanolamine and molybdic acid (H _{2) in 30 mL of water.} A uniform solution was prepared by mixing with a molybdenum-containing solution prepared by mixing and dissolving 52.5 g of _{MoO 4} · H _{2 O).}

<Support-molding>
After 800 g of Ti—Si—W composite oxide powder (mass ratio _{: TiO 2} : SiO ₂ : WO ₃ = 93: 5: 2) is put into a kneader, the above uniform solution is added together with a molding aid such as an organic binder. , Stirred well. After mixing well with a blender while adding an appropriate amount of water, the mixture was sufficiently kneaded with a continuous kneader and extruded into a honeycomb shape having an outer diameter of 25 mm square, a length of 700 mm, an opening of 2.90 mm and a wall thickness of 0.4 mm.

<Drying-baking>
The obtained molded product was dried at 60 ° C. for 1.5 hours and then calcined at 420 ° C. for 5 hours to obtain a catalyst A.

The composition of this catalyst A is TiO ₂ : SiO ₂ : WO ₃ : MoO ₃ : V ₂ O ₅ = 76.3: 4.1: 1.6: 5.0: 7.0 (mass ratio), and BET. The surface area was 84.5 m ² / g and the total pore volume was 0.44 mL / g.

(Example 2)
In Example 1, a vanadium-containing solution prepared by mixing and dissolving 71.3 g of ammonium metavanadate, 128.3 g of oxalic acid, and 38.5 g of monoethanolamine in 90 mL of water, and 36.8 g of monoethanolamine in 30 mL of water. Instead of a homogeneous solution obtained by mixing a molybdenum-containing solution in which 52.5 g of molybdic acid is mixed and dissolved, 71.3 g of ammonium metavanadate, 128.3 g of oxalate and 38.5 g of monoethanolamine are added to 90 mL of water. Except for using a homogeneous solution obtained by mixing a mixed / dissolved vanadium-containing solution and a molybdenum-containing solution obtained by mixing 28.9 g of monoethanolamine and 52.5 g of molybdic acid in 30 mL of water. Catalyst B was obtained in the same manner as in Example 1.

The composition of this catalyst B is TiO ₂ : SiO ₂ : WO ₃ : MoO ₃ : V ₂ O ₅ = 76.3: 4.1: 1.6: 5.0: 7.0 (mass ratio), and BET. The surface area was 84.0 m ² / g, and the total pore volume was 0.42 mL / g.

(Example 3)
In Example 1, a vanadium-containing solution prepared by mixing and dissolving 71.3 g of ammonium metavanadate, 128.3 g of oxalic acid, and 38.5 g of monoethanolamine in 90 mL of water, and 36.8 g of monoethanolamine in 30 mL of water. Instead of a homogeneous solution obtained by mixing a molybdenum-containing solution in which 52.5 g of molybdic acid is mixed and dissolved, 71.3 g of ammonium metavanadate, 128.3 g of oxalate and 38.5 g of monoethanolamine are added to 90 mL of water. Except for using a uniform solution obtained by mixing a mixed / dissolved vanadium-containing solution and a molybdenum-containing solution obtained by mixing 18.4 g of monoethanolamine and 52.5 g of molybdic acid in 30 mL of water. Catalyst C was obtained in the same manner as in Example 1.

The composition of this catalyst C is TiO ₂ : SiO ₂ : WO ₃ : MoO ₃ : V ₂ O ₅ = 76.3: 4.1: 1.6: 5.0: 7.0 (mass ratio), and BET. The surface area was 83.4 m ² / g, and the total pore volume was 0.42 mL / g.

(Example 4)
In Example 1, a vanadium-containing solution prepared by mixing and dissolving 71.3 g of ammonium metavanadate, 128.3 g of oxalic acid, and 38.5 g of monoethanolamine in 90 mL of water, and 36.8 g of monoethanolamine in 30 mL of water. Instead of a homogeneous solution obtained by mixing a molybdenum-containing solution in which 52.5 g of molybdic acid is mixed and dissolved, 71.3 g of ammonium metavanadate, 128.3 g of oxalate and 38.5 g of monoethanolamine are added to 90 mL of water. Except for using a homogeneous solution obtained by mixing a mixed / dissolved vanadium-containing solution and a molybdenum-containing solution obtained by mixing 13.1 g of monoethanolamine and 52.5 g of molybdic acid in 30 mL of water. Catalyst D was obtained in the same manner as in Example 1.

The composition of this catalyst D is TiO ₂ : SiO ₂ : WO ₃ : MoO ₃ : V ₂ O ₅ = 76.3: 4.1: 1.6: 5.0: 7.0 (mass ratio), and BET. The surface area was 81.1 m ² / g and the total pore volume was 0.42 mL / g.

(Comparative Example 1)
In Example 1, a vanadium-containing solution prepared by mixing and dissolving 71.3 g of ammonium metavanadate, 128.3 g of oxalic acid, and 38.5 g of monoethanolamine in 90 mL of water, and 36.8 g of monoethanolamine in 30 mL of water. Instead of a homogeneous solution obtained by mixing a molybdenum-containing solution in which 52.5 g of molybdic acid was mixed and dissolved, 71.3 g of ammonium metavanadate, 128.4 g of oxalic acid and 38.5 g of monoethanolamine were added to 120 mL of water. Further, a catalyst E was obtained in the same manner as in Example 1 except that a uniform solution in which 52.5 g of molybdic acid was mixed and dissolved was used.

The composition of this catalyst E is TiO ₂ : SiO ₂ : WO ₃ : MoO ₃ : V ₂ O ₅ = 76.3: 4.1: 1.6: 5.0: 7.0 (mass ratio), and BET. The surface area was 76.7 m ² / g, and the total pore volume was 0.50 mL / g.

(Comparative Example 2)
In Example 1, a vanadium-containing solution prepared by mixing and dissolving 71.3 g of ammonium metavanadate, 128.3 g of oxalic acid, and 38.5 g of monoethanolamine in 90 mL of water, and 36.8 g of monoethanolamine in 30 mL of water. Instead of the uniform solution obtained by mixing 52.5 g of molybdic acid with a molybdenum-containing solution, 71.3 g of ammonium metavanadate, 128.4 g of oxalic acid, and 52.5 g of molybdic acid were added to 120 mL of water. A catalyst F was obtained in the same manner as in Example 1 except that a mixed / dissolved homogeneous solution was used.

The composition of this catalyst F is TiO ₂ : SiO ₂ : WO ₃ : MoO ₃ : V ₂ O ₅ = 76.3: 4.1: 1.6: 5.0: 7.0 (mass ratio), and BET. The surface area was 83.3 m ² / g, and the total pore volume was 0.42 mL / g.

(NOx removal test)
Using the catalysts A to F obtained in Examples 1 to 5 and Comparative Example 1, the NOx removal performance was evaluated under the following performance conditions.

[NOx removal performance evaluation conditions]
NOx: 200ppm
NH ₃ : 200ppm
O ₂ : 10% by volume
H ₂ O: 15% by volume
N ₂ : balance
Gas temperature: 175 ° C
Space velocity: 26,000h-1 (STP)
Gas ray velocity: 0.7 m / s (STP)
Next, the NOx concentrations at the catalyst inlet and catalyst outlet were measured, and the denitration rate (NOx removal rate) was calculated according to the following equation. The results are shown in Table 1.

(Chlorotoluene decomposition test)
Chlorotoluene decomposition performance was evaluated under the following conditions using the catalysts A to F obtained in Examples 1 to 5 and Comparative Example 1.

[Chlorotoluene decomposition performance evaluation conditions]
Chlorotoluene: 30ppm
O ₂ : 10% by volume
H ₂ O: 15% by volume
N ₂ : balance
Gas temperature: 200 ° C
Space velocity: 8250h-1 (STP)
Gas ray velocity: 0.5 m / s (STP)
Next, the chlorotoluene (CT) concentrations at the catalyst inlet and catalyst outlet were measured, and the chlorotoluene (CT) decomposition rate was calculated according to the following equation. The results are shown in Table 1.

Claims (4)

A method for producing an inorganic composite oxide, which comprises a supporting step of supporting a vanadium compound and a molybdenum compound on an oxide containing titanium and silicon, tungsten and / or vanadium, and a firing step. Contains a vanadium compound, a molybdenum compound, and a compound containing a nitrogen atom having a structure as a blended base, and the molar ratio (N / Mo) of the nitrogen atom to the molybdenum atom is 4.5 to 6.5. A method for producing an inorganic composite oxide, which comprises using an aqueous solution. The first aspect of claim 1, wherein the amount of total vanadium used in the method for producing the inorganic composite oxide is adjusted to be 1 to 20% by mass with respect to the inorganic composite oxide in terms of vanadium pentoxide. Method for producing an inorganic composite oxide. The method for producing an inorganic composite oxide according to claim 1 or 2, wherein the method for preparing the aqueous liquid is any one of the following (a) to (c).
(A) A method of mixing a liquid containing a vanadium compound and a liquid containing an additional basic nitrogen compound and a molybdenum compound with a liquid containing oxalic acid.
(B) A method of mixing a liquid containing a vanadium compound, an additional basic nitrogen compound and a molybdenum compound with oxalic acid and an additional basic nitrogen compound.
(C) A method of mixing a liquid containing a vanadium compound and a molybdenum compound with oxalic acid and an additional basic nitrogen compound. The exhaust gas containing a nitrogen oxide and / or an organic halogen compound is treated by using the inorganic composite oxide obtained by the method for producing an inorganic composite oxide according to claims 1 to 3 as a catalyst. Exhaust gas treatment method.