JP2017064627A - Catalyst for exhaust gas treatment and method of producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst for exhaust gas treatment exhibiting high denitration performance even when used for treatment of low temperature exhaust gas, furthermore is hardly inactivated even when used for treatment of exhaust gas containing many poisoning components including alkali metal or alkali earth metal and including ammonium sulfates.SOLUTION: There is provided the catalyst for exhaust gas treatment that includes a carrier, a structure restricting agent and an active metal component. The carrier satisfies the following condition: a specific surface area A (SA) of a catalyst pore of 5 nm to 5400 nm measured by a mercury intrusion porosimetry method is in the range of 25 to 50 m/g; there is a maximum peak X in the range of 20 to 50 nm in pore diameter distribution; and a specific surface area SAof pores in the range of X×10to X×10nm for pore diameter of the maximum peak X to all specific surface area of the catalyst SAis in the range of SA/SA=0.65 to 0.90. The carrier is composed of at least one or more kind of inorganic single oxide and/or inorganic compound oxide of titanium oxide and/or titanium compound oxide.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an exhaust gas treatment catalyst and a method for producing the same.

  For example, when heat recovery is performed with exhaust gas, the exhaust gas temperature may be about 80 ° C. Therefore, development of a catalyst that exhibits high denitration performance even when such low temperature (about 70 to 250 ° C.) exhaust gas is treated is desired.

  In addition, as a method for removing nitrogen oxides in combustion exhaust gas, a method of catalytic decomposition in the presence of ammonia as a reducing agent is known. However, since combustion exhaust gas normally contains sulfur dioxide. In the case where the decomposition temperature is 300 ° C. or lower, there is a problem that ammonium sulfate is precipitated on the catalyst surface due to the reaction with ammonia and the catalyst performance is lowered.

  Further, if the exhaust gas contains a poisoning substance for the exhaust gas treatment catalyst, the exhaust gas treatment catalyst tends to be deactivated. Here, alkali metals and alkaline earth metals are listed as main poisoning substances. For example, it is known that the main component of dust contained in cement manufacturing exhaust gas is calcium (see Patent Document 1).

JP 2013-49580 A

  The present invention exhibits high denitration performance even when exhaust gas at a low temperature (about 70 to 250 ° C.) is treated, and further contains a lot of poisonous components containing alkali metal or alkaline earth metal (especially calcium) and ammonium sulfate. An object of the present invention is to provide a catalyst for exhaust gas treatment that is difficult to deactivate even when used for exhaust gas, and a method for producing the same.

  In addition, it is desired to develop a catalyst having high denitration performance and heat resistance even when exhaust gas at 300 to 600 ° C. such as gas turbine exhaust gas using LNG as a fuel is treated.

The inventor has intensively studied in order to solve the above problems, and has completed the present invention.
The present invention includes the following (1) to (7).
(1) (i) The specific surface area A (SA _Hg ) of catalyst pores of 5 to 5400 nm by mercury porosimetry is in the range of 25 to 50 m ² / g.
(Ii) pore size distribution with a maximum peak X in the range of 20-50 nm,
Relative pore diameter X of (iii) the maximum ^{peak, X × 10 -0.25 ~X × 10} +0.25 nm specific surface area SA _X occupied by pore size in the range of, relative to the total specific surface area SA _total catalyst, SA _X / SA _total = 0.65 to 0.90.
A carrier satisfying the above conditions (i) to (iii) and comprising at least one inorganic single oxide and / or inorganic composite oxide of titanium oxide and / or titanium composite oxide, a structure regulating agent, An exhaust gas treatment catalyst comprising an active metal component.
(2) The carrier is an inorganic single oxide composed of TiO ₂ and / or an inorganic composite oxide of Ti and at least one selected from the group consisting of W, Mo, Si and V, The exhaust gas treatment catalyst according to (1) above.
(3) The exhaust gas treatment according to (1) or (2), wherein the active metal component is at least one selected from the group consisting of vanadium, molybdenum, manganese, lanthanum, yttrium, and cerium. Catalyst.
(4) The exhaust gas treatment catalyst according to any one of (1) to (3), wherein the structure regulating agent is a compound containing silicon and / or calcium.
(5) Step (a): A slurry containing Ti, or a slurry containing Ti and at least one selected from the group consisting of W, Mo, Si, and V and dehydrated, fired, and inorganic made of TiO ₂ A step of obtaining a single oxide raw material or an inorganic composite oxide raw material of Ti and at least one selected from the group consisting of W, Mo, Si, and V.
Step (b): A mixture containing the inorganic single oxide raw material and / or inorganic composite oxide raw material obtained in step (a), a compound containing silicon and / or calcium, and an active metal component is molded. , Drying and firing.
The manufacturing method of the catalyst for exhaust gas treatment in any one of said (1)-(4) containing this.
(6) After molding the mixture in step (b), in an environment where the humidity is reduced to 30% at a rate in the range of 0.20 to 0.97% / hr from an environment where the humidity is 90% or more. The method for producing an exhaust gas treatment catalyst according to the above (5), further comprising a drying step characterized by drying with a gas.
(7) An exhaust gas treatment method for treating exhaust gas using the exhaust gas treatment catalyst according to any one of (1) to (4) above.

  According to the present invention, even when exhaust gas at a low temperature (about 70 to 250 ° C.) is treated, high NOx removal performance is exhibited, and further poisonous components and alkali sulfates containing alkali metal or alkaline earth metal (especially calcium) are provided. It is possible to provide an exhaust gas treatment catalyst and a method for producing the exhaust gas treatment catalyst which are hardly deactivated even when used in a large amount of exhaust gas.

It is a schematic perspective view of the suitable example of a honeycomb structure. 1 is a pore size distribution diagram of a catalyst of Example 1. FIG. 2 is a pore size distribution diagram of a catalyst of Example 2. FIG. 4 is a pore size distribution diagram of the catalyst of Example 3. FIG. 6 is a pore size distribution diagram of the catalyst of Example 4. FIG. 2 is a pore size distribution diagram of a catalyst of Comparative Example 1. FIG.

<Exhaust gas treatment catalyst of the present invention>
The exhaust gas treatment catalyst of the present invention will be described. The exhaust gas treatment catalyst of the present invention is hereinafter also referred to as “the catalyst of the present invention” or “catalyst”.

<Carrier>
The carrier in the catalyst of the present invention will be described.
In the catalyst of the present invention, the support is a mixture of TiO ₂ and an inorganic composite oxide, or each is a single support.

The inorganic composite oxide means any composite oxide of Ti and at least one selected from the group consisting of W, Mo, Si and V.
The total oxide equivalent concentration of W, Mo, Si, and V in the composite oxide is preferably 0.05 to 40% by mass, and more preferably 0.1 to 20% by mass. .

  The catalyst preferably contains 50 to 95% by mass, and more preferably 70 to 95% by mass of the above-mentioned mixture of inorganic single oxide and inorganic composite oxide or a single carrier.

<Structure regulator>
The catalyst also contains a structure regulating agent. By using a structure-regulating agent, it is possible to prepare a material having excellent pore distribution controllability and a sharp pore distribution. Furthermore, it becomes possible to easily control the shape and directionality of the pores.
Further, as the structure restricting agent, an inorganic structure restricting agent is preferable, and examples thereof include carbon fibers, ceramic fibers, glass fibers, synthetic fibers, and chops or whiskers thereof. In particular, the structure-regulating agent preferably contains 3 to 20% by mass of a compound containing silicon and / or calcium separately from the mixture of the inorganic single oxide and the inorganic composite oxide as described above. More preferably, it is 5-10 mass%. Either crystalline or non-crystalline may be used.

  Examples of the compound containing silicon and / or calcium that may be contained in the structure-regulating agent include compounds having a structure such as MCM-41, 48, SBA-15, and SBA-16, porous silica (micelle template silica) (Langmuir 16 ( 2), 356 (2000)), and may be an amorphous glass fiber or a clay-based crystal mineral such as a montmorillonite mineral.

  Furthermore, the shape of the structure regulating agent may be a fiber shape, a column shape, a spindle shape, or a plate shape.

<Active metal component>
The active metal component in the catalyst of the present invention will be described.
In the catalyst of the present invention, an active metal component is supported on the carrier as described above.
In the catalyst of the present invention, the active metal component is preferably at least one selected from the group consisting of tungsten, vanadium, molybdenum, manganese, lanthanum, yttrium and cerium.

The catalyst of the present invention contains components other than the carrier and active metal component as described above in a proportion of 20% by mass or less, preferably 15% by mass or less, more preferably 10% by mass or less, and further preferably 7% by mass or less. But you can. Moreover, it is preferable that the catalyst of the present invention substantially comprises the carrier, a structure regulating agent, and the active metal component. Here, “substantially” means that impurities and the like that are inevitably contained from the raw material and the production process can be contained, but other than that are not contained.
Examples of the components other than the carrier, the structure regulating agent and the active metal component as described above include Cr, Fe, Co, Ni, Cu, Ag, Au, Pd, Nd, In, Sn, and Ir.

<Catalyst>
The honeycomb structure in the catalyst of the present invention will be described as an example. In addition to the honeycomb structure, the shape of the catalyst of the present invention can be selected from a columnar shape and a pipe shape.

The catalyst of the present invention has a specific surface area A of the catalyst pore diameter of 5400nm from 5nm by mercury intrusion porosimetry method (SA _Hg) is in the range of 25~50m ² / g, it is preferably 30 to 50 m ² / g .

  The mercury intrusion porosimetry method is a mercury intrusion method using a porosimeter, and can be measured using, for example, a conventionally known measuring apparatus.

In the catalyst of the present invention, the pore size distribution has a maximum peak in the range of 20 to 50 nm, and the pore size is X × 0.562 (= The specific surface area SA _X occupied by the pore diameter in the range of 10 ^−0.25 ) to X × 1.78 (= 10 ^+0.25 ) nm is SA _X / SA _total is 0.65 with ^{respect to} the total specific surface area SA _{total of the} catalyst. ~ 0.90. The SA _X value is preferably 25 to 30 m ² / g.
If SA _X / SA _total is in the range of 0.65 to 0.90, the reason is not clear. For example, in a low temperature range of 70 to 250 ° C., diffusion of the reaction gas containing ammonia as a reducing agent and ammonia It is considered that the adsorption to the active site is balanced and low temperature denitration is exhibited.
When SA _X / SA _total is in the above range, it exhibits high denitration performance when exhaust gas at a low temperature of 70 ° C. is treated, and is further a poisoned component containing alkali metal or alkaline earth metal (especially calcium). In addition, it is difficult to deactivate even when used in exhaust gas containing a large amount of ammonium sulfate.

  Further, the catalyst of the present invention exhibits high denitration performance in the range of about 70 to 600 ° C., and at the same time has high heat resistance.

<Honeycomb structure>
The catalyst of the present invention is preferably a honeycomb-like structure in which an active metal component is supported on the carrier as described above.
The honeycomb structure means a structure having a large number of small holes (cells) penetrating in parallel. The catalyst having such a structure is usually used in a state of being closely fitted in a reaction tube. The cell shape (cross-sectional shape) includes a hexagon, a quadrangle, a triangle, and a circle. In general, the size (diameter) of the cells is open, the partition between the cells is a partition, and the distance between the centers of the left and right or upper and lower walls facing each other is called a pitch.

FIG. 1 illustrates a schematic perspective view of a honeycomb-like structure corresponding to the catalyst of the present invention.
In FIG. 1, the catalyst (1) of the present invention has 8 × 8 cells (3), and the cross-sectional shape of the cells (3) has a rectangular shape. The size (diameter) of the cell (3) is the opening width (5), the partition (7) between the cells (3) and (3), and the thickness (9) of the partition (7) is thick. Also called. Furthermore, let the surface which the opening part of the cell (3) exposes be an end surface (11), and let the other surface be a side surface (13). Further, let X be the length in the longitudinal direction of the honeycomb structure.

<Method for producing catalyst of the present invention>
Next, the manufacturing method of the catalyst of this invention is demonstrated.
In the catalyst of the present invention, the carrier can be produced by the method described in, for example, JP-A Nos. 2004-41893 and 2005-021780.
The catalyst of the present invention is a method of obtaining a mixture obtained by mixing the carrier or a raw material thereof and the active metal component or the raw material, and then forming the mixture into a honeycomb structure by an extrusion molding method or the like. It can be produced by a method of impregnating / supporting the carrier component and the active component on the substrate, and a method of impregnating / supporting the carrier component of the honeycomb structure with the active component.

The catalyst of the present invention is preferably produced by a production method comprising the following steps (a) to (b).
Step (a): Inorganic single oxidation comprising TiO ₂ by dehydrating and firing a slurry containing Ti or a slurry containing Ti and at least one selected from the group consisting of W, Mo, Si and V A step of obtaining a raw material or an inorganic composite oxide raw material of Ti and at least one selected from the group consisting of W, Mo, Si, and V.
Step (b): The mixture containing the inorganic single oxide raw material or inorganic composite oxide raw material obtained in step (a), the compound containing silicon and / or calcium, and the active metal component is extruded into a honeycomb shape. Forming, drying and firing.
Each process of such a preferable manufacturing method is demonstrated below.

<Process (a)>
In the step (a), first, a slurry containing Ti or a slurry containing Ti and at least one selected from the group consisting of W, Mo, Si, and V is obtained.
This slurry is prepared by, for example, dissolving a compound containing Ti or a compound containing W, Mo, Si, and V in a solvent such as water, and then adjusting the pH with an acid or alkali to thereby obtain an oxide of Ti. Further, it can be obtained by further depositing oxides of W, Mo, Si, and V. After the precipitation, it is preferably aged at 20 to 98 ° C. for 0.5 to 24 hours.

  Here, the compound containing Ti is preferably a titanium sulfate solution or a metatitanic acid obtained from a production process of titanium dioxide by a sulfuric acid method.

  Examples of the compound containing W include tungsten-containing nitrogen compounds such as ammonium paratungstate, ammonium metatungstate, ammonium phosphotungstate and ammonium tetrathiotungstate, tungsten-containing sulfur compounds such as tungsten disulfide and tungsten trisulfide, and hexachloride. Examples thereof include tungsten, tungsten dichloride, tungsten trichloride, tungsten tetrachloride, tungsten pentachloride, tungsten dichloride dioxide, and tungsten tetrachloride oxide.

  Compounds containing Mo include molybdenum-containing nitrogen compounds such as ammonium paramolybdate, ammonium metamolybdate, ammonium phosphomolybdate and ammonium tetrathiomolybdate, molybdenum-containing sulfur compounds such as molybdenum disulfide and molybdenum trisulfide, and hexachloride. Examples include molybdenum, molybdenum dichloride, molybdenum trichloride, molybdenum tetrachloride, molybdenum pentachloride, molybdenum dichloride dioxide, and molybdenum tetrachloride oxide.

  Examples of the compound containing Si include silica sol, silicic acid solution, fumed silica, and silicon alkoxide.

  Examples of the compound containing V include vanadyl sulfate, vanadyl oxalate, and ammonium metavanadate.

When using a compound containing W, Mo, Si, and V in addition to the compound containing Ti, the amount ratio of the compound containing Ti and the compound containing W, Mo, Si, and V is not particularly limited, but TiO ₂ (converted value all is assumed to be of TiO ₂ Ti) is preferably adjusted to be 3 to 20 wt% with respect to 100 wt%.

After obtaining the slurry as described above, this is dehydrated and fired.
The dehydration method is not particularly limited, and for example, a conventionally known method, specifically, a centrifugal separation method or the like can be applied for dehydration.
The firing method is not particularly limited, and for example, it can be fired using a conventionally known method, specifically, a firing furnace or the like. The firing temperature is, for example, 110 ° C. or higher (preferably 300 ° C. or higher) and 700 ° C. or lower.
The cake obtained after dehydration may be dried before baking. For drying, for example, a conventionally known method, specifically, an electric dryer or the like can be used. A drying temperature shall be 30-200 degreeC, for example.

  By such a step (a), a slurry containing Ti or an inorganic composite oxide raw material containing Ti and at least one selected from the group consisting of W, Mo, Si, and V can be obtained.

<Step (b)>
In the step (b), the inorganic single oxide raw material or the inorganic composite oxide raw material obtained in the step (a), the compound containing silicon and / or calcium, and the active metal component are mixed after adding moisture. Is preferred.
Although the mixing ratio is not particularly limited, the inorganic single oxide raw material or the inorganic composite oxide raw material, the compound containing silicon and / or calcium, the active metal component, and the total of the moisture and the inorganic single oxide raw material or Ratio of inorganic composite oxide raw material ((inorganic single oxide raw material or inorganic composite oxide raw material) / (inorganic single oxide raw material or inorganic composite oxide raw material + compound containing silicon and / or calcium + active metal component + Moisture) × 100) is preferably 10 to 70% by mass.
Further, ratio of compound containing silicon and / or calcium ((compound containing silicon and / or calcium) / (inorganic single oxide raw material or inorganic composite oxide raw material + silicon and / or calcium containing compound + active metal component) + Moisture) × 100) is preferably 15% by mass or less.
The ratio of active metal component (active metal component / (inorganic single oxide raw material or inorganic composite oxide raw material + compound containing silicon and / or calcium + active metal component + moisture) × 100) is 5% by mass or less. Preferably there is.

  As described above, when mixing the inorganic single oxide raw material or the inorganic composite oxide raw material, the compound containing silicon and / or calcium, and the active metal component with the addition of moisture, a molding aid is added as necessary. An agent may be further added and mixed.

  As the molding aid, for example, conventionally known ones can be used, and specific examples include organic substances such as polyethylene oxide, crystalline cellulose, glycerin, and polyvinyl alcohol.

  Then, the obtained mixture is formed into, for example, a honeycomb using a conventionally known molding machine, and then fired. It is preferable to dry after shaping | molding here.

  As a drying method, it is preferable to dry in an environment in which the humidity is reduced to 30% at a rate in the range of 0.20 to 0.97% / hr from an environment having a humidity of 90% or more after molding. Specifically, it can be dried by applying a humidity-conditioning dryer or the like. A drying temperature shall be 30-200 degreeC, for example.

  When the rate of decrease in humidity is faster than 0.97% / hr, cracks may occur, and there is a possibility that the strength of the molded body and the like will be unpractical.

  When the rate of decrease in humidity is slower than 0.20% / hr, there is a possibility that the production efficiency is poor and the application is not possible.

  The firing method is not particularly limited, and for example, it can be fired using a conventionally known method, specifically, a firing furnace or the like. The firing temperature is, for example, 400 to 700 ° C.

By such a production method of the present invention, the catalyst of the present invention can be obtained.
<Exhaust gas treatment method>

  The catalyst of the present invention can be preferably used as an exhaust gas treatment catalyst for thermal power plant exhaust gas, cement production exhaust gas, waste incineration exhaust gas, glass melting furnace exhaust gas, and steel coke oven.

  The catalyst of the present invention can also be used in an apparatus for decomposing and removing organic chlorinated compounds (such as dioxins) in exhaust gas.

  When the exhaust gas contains mercury, the catalyst of the present invention can also be used in an apparatus for installing the catalyst and halogenating mercury.

  Hereinafter, the present invention will be described based on examples. The present invention is not limited to these examples.

[Raw material preparation 1 (Ti oxide raw material: TiO ₂ raw material-1)]
A metatitanic acid slurry (manufactured by Ishihara Sangyo Co., Ltd.) was charged into a stirrer equipped with a reflux condenser, and 35% by mass H ₂ O ₂ water was added to 90 parts by mass of TiO _{2 so} that H ₂ O ₂ was 9 parts by mass, 25% by mass aqueous ammonia was gradually added so as to have a pH of 9.0, and then the mixture was aged at 40 ° C. for 3 hours while being sufficiently stirred. Thereafter, 25% by mass sulfuric acid aqueous solution is gradually added so that the pH becomes 2.0, and then sufficient stirring is performed at 40 ° C. for 1 hour. Further, 25% by mass ammonia water is adjusted to pH 7.5. Then, the mixture was aged at 40 ° C. for 3 hours with sufficient agitation. And the obtained slurry was dehydrated and washed, and the dehydrated cake was dried at 110 ° C. and baked at 150 ° C. to obtain Ti oxide raw material-1.

[Raw material preparation 2 (Ti oxide raw material: TiO ₂ raw material-2)]
After charging metatitanic acid slurry (Ishihara Sangyo Co., Ltd.) into a stirrer equipped with a refluxer and adding 25% by mass ammonia water to a pH of 7.5 or higher, heat aging with sufficient stirring for 3 hours at 60 ° C. did. And the obtained slurry was dehydrated and washed, and the dehydrated cake was dried at 110 ° C. and baked at 600 ° C. to obtain Ti oxide raw material-2.

[Raw material preparation 3 (Ti—W—V raw material: TiO ₂ -5 mass% WO ₃ −4.35% V ₂ O ₅ composite oxide raw material]]
Charged metatitanic acid slurry (manufactured by Ishihara Sangyo) in a reflux condenser fitted with a stirrer, a 35 wt% H ₂ O ₂ water against TiO ₂ 88.5 parts by weight of a, and H ₂ O ₂ is 8.9 parts by weight Further, ammonium paratungstate (manufactured by Nippon Shin Metals Co., Ltd.) was added so that WO ₃ was 5 parts by mass with respect to 88.85 parts by mass of TiO ₂ , and vanadyl sulfate (Emerging Chemicals) was added. Kogyo Co., Ltd.) was added so that V ₂ O ₅ was 6.15 parts by mass with respect to 88.85 parts by mass of TiO ₂ , and 25% by mass aqueous ammonia was added so that the pH was 7.5 or more. Thereafter, the mixture was aged by heating with sufficient stirring at 60 ° C. for 3 hours. And the obtained slurry was dehydrated and washed, and the dehydrated cake was dried at 110 ° C. and then calcined at 400 ° C. to obtain a Ti—W—V composite oxide raw material A. Next was charged metatitanic acid slurry (manufactured by Ishihara Sangyo) in a reflux condenser fitted with a stirrer, this to Ti-W-V complex oxide material A, Ti-W- respect TiO ₂ 30 parts by weight from metatitanic acid slurry After adding V composite oxide raw material A to 70 parts by mass and further gradually adding 25% by mass ammonia water to pH 7.2 to this, sufficient stirring is performed at 40 ° C. for 3 hours. Aged at constant temperature. And the obtained slurry was dehydrated and washed, and the dehydrated cake was dried at 110 ° C. and then fired at 600 ° C. to obtain a Ti—W—V composite oxide raw material.

[Raw material preparation 4 (Ti—Mo—Si raw material: TiO ₂ -5 mass% MoO ₃ -10 mass% SiO ₂ composite oxide raw material composite oxide raw material]]
A metatitanic acid slurry (manufactured by Ishihara Sangyo) was charged into a stirrer equipped with a reflux condenser, and 35% by mass of H ₂ O ₂ water was added to 90 parts by mass of TiO _{2 so} that H ₂ O ₂ was 10 parts by mass. Further, ammonium paramolybdate was added so that MoO ₃ was 5 parts by mass with respect to 85 parts by mass of TiO ₂ , and further silica sol (manufactured by JGC Catalysts & Chemicals, S-20L) was added to 85 parts by mass of TiO _2. SiO ₂ was added to 10 parts by mass, and 25% by mass ammonia water was gradually added to pH 7.2, followed by sufficient stirring at 40 ° C. for 24 hours. Aged at constant temperature. And the obtained slurry was dehydrated and washed, and the dehydrated cake was dried at 110 ° C. and then fired at 500 ° C. to obtain a Ti—Mo—Si composite oxide raw material.

[Raw material preparation 5 (Ti—Si raw material: TiO ₂ -20 mass% SiO ₂ composite oxide raw material)]
A sulfuric acid solution of titanyl sulfate (Teica TM crystal dissolved in water) was charged into a stirrer equipped with a reflux condenser, and 35% by mass of H ₂ O ₂ water was added to 80 parts by mass of TiO _{2 with} respect to H ₂ O _2. The silica sol (manufactured by JGC Catalysts & Chemicals Co., Ltd., S-20L) is added thereto so that the SiO ₂ is 20 parts by mass with respect to 80 parts by mass of TiO _2. 32.5% by mass of urea water was added to 80 parts by mass of TiO ₂ so that urea was 27 parts by mass, heated to 95 ° C., and then aged with sufficient stirring for 12 hours. And the obtained slurry was dehydrated and washed, and the dehydrated cake was dried at 110 ° C. and then fired at 500 ° C. to obtain a Ti—Si composite oxide raw material.

<Catalyst preparation>

[Example 1]
Ti oxide raw material-1 obtained as described above, 12.7 kg, ammonium metavanadate (manufactured by Shinsei Chemical Industry) 1.285 kg, ammonium paramoridenate (manufactured by Taiyo Mining) 920 g, glass fiber 1.25 kg, 2.10 kg of 25% by mass ammonia water, water, 125 g of polyethylene glycol (PEG-20000, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), 125 g of crystalline cellulose (Theorus TG-101) are added, and a mixer is added so that the water concentration becomes 30% by mass. After being kneaded in, it was extruded into a honeycomb shape. The obtained molded body was gradually decreased from 90% to 30% in 3 days (equivalent to a reduction rate of 0.83% / hr), and the temperature was gradually increased from 40 ° C. to 60 ° C. in 3 days. Dried in a dry environment. Then, it baked at 500 degreeC for 3 hours, and obtained the catalyst. The obtained honeycomb catalyst had a partition wall thickness of 0.50 mm, an opening of 3.20 mm, and an outer shape of 75 mm.

[Comparative Example 1]
Similarly, to the Ti oxide raw material-2, 24.7 kg obtained as described above, 1.285 kg of ammonium metavanadate (manufactured by Shinsei Chemical Industry Co., Ltd.), 2.30 kg of 25 mass% ammonia water, water, polyethylene glycol ( 125 g of PEG-20000 (Daiichi Kogyo Seiyaku Co., Ltd.) and 125 g of crystalline cellulose (Theolas TG-101) were added, kneaded so that the water concentration was 30% by mass, then formed into a honeycomb shape, and dried as in Example 1. After drying under the conditions, firing was performed at 500 ° C. for 3 hours to obtain a honeycomb-shaped catalyst having a partition wall thickness of 0.50 mm, an opening of 3.20 mm, and an outer diameter of 75 mm.

[Example 2]
To 23.7 kg of the Ti-W-V composite oxide raw material obtained as described above, 1.02 kg of lanthanum nitrate hexahydrate, 1.28 kg of yttrium nitrate hexahydrate, 1.25 kg of glass fiber, 25% by mass 2.10 kg of aqueous ammonia, water, 125 g of polyethylene glycol (PEG-20000 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 125 g of crystalline cellulose (Theolas TG-101) were added and kneaded with a mixer so that the water concentration was 30% by mass. Thereafter, it was formed into a honeycomb shape, dried under the same drying conditions as in Example 1, and then fired at 500 ° C. for 3 hours to obtain a honeycomb catalyst having a partition wall thickness of 0.50 mm, an opening of 3.20 mm, and an outer diameter of 75 mm. It was.

[Example 3]
To 22.7 kg of the Ti—Mo—Si composite oxide raw material obtained as described above, 4.52 kg of 50 mass% manganese nitrate aqueous solution, 1.89 kg of cerous nitrate hexahydrate, 1.25 kg of activated clay, 2.10 kg of 25% by mass ammonia water, water, 125 g of polyethylene glycol (PEG-20000, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), 125 g of crystalline cellulose (Theorus TG-101) are added, and a mixer is added so that the water concentration becomes 30% by mass. After being kneaded in, formed into a honeycomb shape, dried under the same drying conditions as in Example 1, and then fired at 500 ° C. for 3 hours to form a honeycomb shape having a partition wall thickness of 0.50 mm, an opening of 3.20 mm, and an outer diameter of 75 mm. A catalyst was obtained.

[Example 4]
Similarly, a catalyst was obtained in the same manner as in Example 1 except that 22.7 kg of the Ti—Si composite oxide raw material was used.

[Comparative Example 2]
As in Example 2, after forming into a honeycomb shape, the obtained material was rapidly reduced from 90% to 30% humidity in one day (equivalent to a rate of reduction of 2.5% / hr), and the temperature was changed to 40%. Drying was performed in an environment where the temperature was rapidly increased from 60 ° C. to 60 ° C. in one day. As a result, many cracks were generated in the honeycomb, and the sample could not be collected.

[Test Example 1] Estimation of specific surface area by measurement of specific surface area of mercury porosimeter With respect to each catalyst obtained in Examples and Comparative Examples, specific surface area distribution measurement in the range of 5 nm to 5400 nm was performed using a mercury porosimeter.
Mercury porosimeter specific surface area measuring device: Quantachrome PoreMaster
Mercury porosimeter specific surface area measurement conditions: pretreatment 300 ° C. for 1 hour, mercury intrusion angle 130 °, surface tension 473 erg / cm ²

  FIG. 1 to FIG. 5 show the catalyst specific surface area distribution of 5 nm to 500 nm among the catalyst specific surface area distribution of 5 nm to 5400 nm by mercury porosimetry of each catalyst. Note that there was no distinguishable specific surface area peak at 500 nm or more.

[Test Example 2] Accelerated deterioration test of catalyst by CaCl ₂ solution spray and ammonium sulfate Each catalyst obtained in Examples and Comparative Examples was cut into 4 × 4 × 107 mmL (thickness: 0.50 mm, opening size) (Width: 3.20 mm) After setting in a quartz reaction tube, the catalyst denitration performance in the Fresh state was measured. Here, the denitration rate of nitrogen oxide (NOx) in the gas before and after contact with the catalyst can be obtained by the following equation. At this time, the concentration of NOx was measured with a chemiluminescent nitrogen oxide analyzer (ECL-88AO, manufactured by Abatech Yanaco).
Denitration rate (%) = {(NOx in noncontact gas (volume ppm) −NOx in gas after contact (volume ppm)) / NOx in noncontact gas (volume ppm)} × 100
The initial denitration rate obtained here was defined as η ₀ (%). The calculated reaction rate constant _{k 0 = -AV × ln (1} -η 0/100).
Thereafter, a nozzle for spraying the CaCl ₂ solution was attached to the quartz reaction tube, and the CaCl ₂ solution was added from the upstream side of the catalyst. The nozzle was installed 300 mm away from the upstream end face of the quartz reaction tube. The concentration of the CaCl ₂ solution was 0.1% by mass, and the spraying time was 48 hours. After spraying the CaCl ₂ solution, the denitration performance of the catalyst was measured again. The post-degradation denitration rate obtained here was calculated from η (%) as k = −AV × ln (1−η / 100). Then, in search of k / k _0, it was compared with the performance of the Fresh state. Both performance measurement and CaCl ₂ solution spraying were performed at 130 ° C. The measurement conditions are as shown below.
Activity measurement conditions Reaction temperature: 130 ° C., SV = 3000 (1 / h), gas flow rate = 0.075 (Nm ³ / h), AV = 3.30 (Nm ³ / m ² h), NO = 180 (volume) ppm), NH ₃ = 180 (volume ppm), SO ₂ = 40 (volume ppm), O ₂ = 7 volume%, H ₂ O = 10 volume%, N ₂ = balance accelerated deterioration test conditions SV = 3000 (1 / h), the gas air volume ^{= 0.075 (Nm 3 /h),AV=3.30(Nm 3 /} m 2 h), NO = 0 ( volume ppm), NH ₃ = 0 (volume ppm), SO ₂ = 1000 (volume ppm), O ₂ = 7 vol%, H ₂ O = 10 vol% (as CaCl ₂ solution), N ₂ = balance

The results are shown in Table 1. Compared with the catalyst of Comparative Example 1, it can be seen that the catalysts of Examples 1 to 4 have higher activity even after spraying with CaCl ₂ solution.

[Test Example 3] Low-temperature denitration test Each catalyst obtained in Examples and Comparative Examples was cut into 4 × 4 × 107 mmL (wall thickness: 0.50 mm, opening width: 3.20 mm), quartz reaction After setting the tube, the low temperature denitration performance was measured.
Here, the denitration rate of nitrogen oxides (NO _x ) in the gas before and after contact with the catalyst was determined by the above formula. In this case NO _X concentrations chemiluminescent nitrogen oxide of Formula analyzer (manufactured Anatekku-Yanaco Ltd., ECL-88AO) was measured by.

The measuring method of the low temperature denitration performance is as follows.
Reaction temperature: 110 ° C., superficial velocity (SV) = 3000 hr ⁻¹
Model gas composition: NO _x = 180 vol ppm, NH ₃ = 180 vol ppm, O ₂ = 7 vol%, H ₂ O = 10 vol%, N ₂ = balance

Test Example 4 Denitration Test Each catalyst obtained in Examples and Comparative Examples was cut into 4 × 4 × 272 mmL (wall thickness: 0.50 mm, opening width: 3.20 mm), quartz reaction tube After setting, the denitration performance was measured.
Here, the denitration rate of nitrogen oxides (NO _x ) in the gas before and after contact with the catalyst was determined by the above formula. In this case NO _X concentrations chemiluminescent nitrogen oxide of Formula analyzer (manufactured Anatekku-Yanaco Ltd., ECL-88AO) was measured by.

The measuring method of the low temperature denitration performance is as follows.
Reaction temperature: 350 ° C., superficial velocity (SV) = 29300 hr ⁻¹
Model gas composition: NO _x = 180 vol ppm, NH ₃ = 180 vol ppm, O ₂ = 7 vol%, H ₂ O = 10 vol%, N ₂ = balance

  The results are shown in Table 1.

Claims (7)

(I) The specific surface area A (SA _Hg ) of catalyst pores of 5 nm to 5400 nm by mercury intrusion porosimetry is in the range of 25 to 50 m ² / g.
(Ii) pore size distribution with a maximum peak X in the range of 20-50 nm,
Relative pore diameter X of (iii) the maximum ^{peak, X × 10 -0.25 ~X × 10} +0.25 nm specific surface area SA _X occupied by pore size in the range of, relative to the total specific surface area SA _total catalyst, SA _X / SA _total = 0.65 to 0.90.
A carrier satisfying the above conditions (i) to (iii) and comprising at least one inorganic single oxide and / or inorganic composite oxide of titanium oxide and / or titanium composite oxide, a structure regulating agent, An exhaust gas treatment catalyst comprising an active metal component. 2. The carrier is an inorganic single oxide composed of TiO ₂ and / or an inorganic composite oxide of Ti and at least one selected from the group consisting of W, Mo, Si and V. The catalyst for exhaust gas treatment as described in 1.   3. The exhaust gas treatment catalyst according to claim 1, wherein the active metal component is at least one selected from the group consisting of vanadium, molybdenum, manganese, lanthanum, yttrium, and cerium.   The exhaust gas treatment catalyst according to any one of claims 1 to 3, wherein the structure regulating agent is a compound containing silicon and / or calcium. Step (a): Inorganic single oxidation comprising TiO ₂ by dehydrating and firing a slurry containing Ti or a slurry containing Ti and at least one selected from the group consisting of W, Mo, Si and V A step of obtaining a raw material or an inorganic composite oxide raw material of Ti and at least one selected from the group consisting of W, Mo, Si, and V.
Step (b): A mixture containing the inorganic single oxide raw material and / or inorganic composite oxide raw material obtained in step (a), a compound containing silicon and / or calcium, and an active metal component is molded. , Drying and firing.
The manufacturing method of the catalyst for exhaust gas treatment in any one of Claims 1-4 containing these.   After forming the mixture in the step (b), the mixture is dried in an environment where the humidity is reduced to 30% at a rate in the range of 0.20 to 0.97% / hr from an environment where the humidity is 90% or more. The method for producing an exhaust gas treatment catalyst according to claim 5, further comprising a drying step. An exhaust gas treatment method for treating exhaust gas using the exhaust gas treatment catalyst according to claim 1.