JP6671163B2 - Exhaust gas treatment honeycomb catalyst and method for producing the same - Google Patents

Description

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

  For example, since the exhaust gas from cement production is recovered by heat, the temperature of the exhaust gas may be about 80 ° C. Therefore, development of a catalyst that exhibits high denitration performance when treating such low-temperature (about 70 to 250 ° C.) exhaust gas is desired.

  Further, as a method for removing nitrogen oxides from flue gas, a method of catalytic decomposition in the presence of ammonia as a reducing agent is known, but since sulfur dioxide is usually contained in flue gas, On the other hand, when the decomposition temperature is 300 ° C. or lower, there is a problem that ammonium sulfate precipitates on the surface of the catalyst due to the reaction with ammonia and deteriorates the catalytic performance.

  Furthermore, if the exhaust gas contains a poisoning substance for the exhaust gas treatment catalyst, the exhaust gas treatment catalyst is easily deactivated. Here, the main poisoning substances include alkali metals and alkaline earth metals. For example, it is known that the main component of dust contained in the exhaust gas from cement production is calcium (see Patent Document 1).

JP 2013-49580 A

  INDUSTRIAL APPLICABILITY The present invention exhibits high denitration performance when treating low-temperature (about 70 to 250 ° C.) exhaust gas, and furthermore, a poisoning component containing an alkali metal or an alkaline earth metal (especially calcium) and an exhaust gas containing a large amount of ammonium sulfate. It is an object of the present invention to provide an exhaust gas treating honeycomb catalyst which is hardly deactivated even when used for a catalyst, and a method for producing the same.

The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and have completed the present invention.
The present invention is the following (1) to (8).
(1) An exhaust gas treatment honeycomb catalyst comprising a carrier composed of a mixture of two or more different inorganic single oxides or inorganic composite oxides, and an active metal component,
The difference (SA _BET -SA _Hg ) between the specific surface area (SA _BET ) by the BET method and the specific surface area (SA _Hg ) of the catalyst pores of 5 nm to 5 μm by the mercury intrusion porosimetry is in the range of 25 to 35 m ² / g. An exhaust gas treatment honeycomb catalyst characterized in that:
(2) the carrier comprises a mixture of an A component and a B component,
Wherein component A, an inorganic single oxides consisting TiO _2, or an inorganic composite oxide of at least one and TiO ₂ selected from the group consisting of WO ₃ and MoO _3,
The B component is an inorganic single oxides consisting SiO _2, or at least one inorganic composite oxide of SiO ₂ selected from the group consisting of TiO ₂ and WO _3,
The content of the component A is 10 to 90% by mass,
The exhaust gas treatment honeycomb catalyst according to the above (1), wherein the content of SiO ₂ is 0.05 to 16% by mass.
(3) The partition has a slit of 0.005 mm or more and less than the cell opening width, and the number of slits is equal to the number of partitions (X is the number of cells on one side of the end face of the rectangular honeycomb structure, and X is the number of cells on the other side. (1) or (2) above, which is 0.03 to 3% (per one end face) with respect to X (Y-1) + Y (X-1), where Y is the number of cells. An exhaust gas treatment honeycomb catalyst according to the above.
(4) The exhaust gas treatment honeycomb catalyst according to (3), wherein the maximum length of the slit is 5 to 80% of the length in the longitudinal direction.
(5) The above (1) to (4), wherein the honeycomb cell has a honeycomb cell with a thickness of 0.50 mm and an opening width of 3.20 mm and a compressive strength of 50 to 200 N / cm ² . An exhaust gas treatment honeycomb catalyst according to any one of the above.
(6) The exhaust gas treatment honeycomb catalyst according to any one of the above (1) to (5), wherein the solid content of SiO ₂ contained in the component B is 5 to 20% by mass.
(7) The exhaust gas treatment honeycomb catalyst according to any one of (1) to (6), wherein the active metal component is at least one selected from the group consisting of vanadium, molybdenum, manganese, lanthanum, yttrium, and cerium. .
(8) A method for producing an exhaust gas-treated honeycomb catalyst, comprising the following steps (a) to (c), wherein the exhaust gas-treated honeycomb catalyst according to any one of (1) to (7) is obtained.
Step (a): A slurry containing Ti or a slurry containing Ti and at least one selected from the group consisting of W and Mo is dehydrated and calcined to obtain an inorganic single oxide raw material made of TiO ₂ , or at least one step of obtaining the inorganic composite oxide raw material of TiO ₂ selected from the group consisting of WO ₃ and MoO _3.
Step (b): A slurry containing Si or a slurry containing at least one selected from the group consisting of Ti and W and Si is dehydrated and calcined to obtain an inorganic single oxide raw material made of SiO ₂ , or A step of obtaining a raw material of an inorganic composite oxide of at least one selected from the group consisting of TiO ₂ and WO ₃ and SiO ₂ .
Step (c): mixing the inorganic single oxide raw material or inorganic composite oxide raw material obtained in step (a) with the inorganic single oxide raw material or inorganic composite oxide raw material obtained in step (b) Extruding into a honeycomb shape, forming, drying and firing.

  ADVANTAGE OF THE INVENTION According to this invention, when exhaust gas of low temperature (about 70-250 degreeC) is processed, high denitration performance is exhibited, and the poisoning component containing alkali metal or alkaline earth metal (especially calcium) and ammonium sulfate are further increased. It is possible to provide an exhaust gas treating honeycomb catalyst which is hardly deactivated even when used for a contained exhaust gas, and a method for producing the same.

It is an outline perspective view of a suitable example of a honeycomb structure. It is a schematic diagram for explaining the measuring method of compressive strength.

<Catalyst of the present invention>
The present invention will be described.
The present invention relates to an exhaust gas treating honeycomb catalyst comprising a carrier comprising a mixture of two or more different inorganic monooxides or inorganic composite oxides, and an active metal component, and has a specific surface area (SA _BET ) _measured by a BET method. Exhaust gas treatment honeycomb characterized in that the difference (SA _BET -SA _Hg ) from the specific surface area (SA _Hg ) of the catalyst pores of 5 nm to 5 μm by mercury intrusion porosimetry is in the range of 25 to 35 m ² / g. It is a catalyst.
Hereinafter, such an exhaust gas treatment honeycomb catalyst is also referred to as “catalyst of the present invention”.

The catalyst of the present invention preferably has a specific surface area (SA _BET ) measured by the BET method of 50 to 100 m ² / g, more preferably 60 to 100 m ² / g.

A method for measuring the BET method (BET specific surface area) will be described.
First, a dried sample (0.2 g) is put into a measurement cell, degassed at 300 ° C. for 60 minutes in a nitrogen gas stream, and then the sample is mixed with a mixed gas of 30% by volume of nitrogen and 70% by volume of helium. The liquid nitrogen temperature is maintained in an air stream, and nitrogen is equilibrium-adsorbed to the sample. Next, the temperature of the sample is gradually raised to room temperature while flowing the above-mentioned mixed gas, the amount of nitrogen desorbed during that time is detected, and the specific surface area of the sample is measured by a previously prepared calibration curve.
Such a BET specific surface area measurement method (nitrogen adsorption method) can be performed using, for example, a conventionally known surface area measurement device.

The catalyst of the present invention preferably has a surface area ratio as measured by mercury intrusion porosimetry method (SA _Hg) is 20~60m ² / g, more preferably 25~55m 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 device.

In the catalyst of the present invention, the difference (SA _BET -SA _Hg ) between the specific surface area (SA _BET ) by the BET method and the specific surface area (SA _Hg ) by the mercury intrusion porosimetry method is 25 to 35 m ² / g. This value is preferably from 27 to 30 m ² / g.
When SA _BET -SA _Hg is in the above range, when a low-temperature (about 70 to 250 ° C.) exhaust gas is treated, a high denitration performance is exhibited, and further, an alkali metal or an alkaline earth metal (particularly, calcium) is removed. Even when used in an exhaust gas containing a large amount of poisoning components and ammonium sulfate, it is hardly deactivated.

<Carrier>
The carrier in the catalyst of the present invention will be described.
In the catalyst of the present invention, the support comprises a mixture of two or more different inorganic single oxides or inorganic composite oxides.
Specifically, the carrier is preferably composed of a mixture of two different types of A component and B component.
Where A component, an inorganic single oxides consisting TiO _2, or an inorganic composite oxide of at least one and TiO ₂ selected from the group consisting of WO ₃ and MoO _3. That is, the component A means any of a single oxide containing Ti, a complex oxide containing Ti and W, a complex oxide containing Ti and Mo, and a complex oxide containing Ti, W and Mo. I do.

Also, B component, an inorganic single oxides consisting SiO _2, or is at least one inorganic composite oxide of SiO ₂ is selected from the group consisting of TiO ₂ and WO _3. That is, the B component means any of a single oxide containing Si, a complex oxide containing Si and Ti, a complex oxide containing Si and W, and a complex oxide containing Si, Ti and W. I do.
The B component is preferably a composite oxide containing Si and Ti.
Further, it is preferable that the solid content of SiO ₂ contained in the component B is 5 to 40% by mass.

  The content of the component A in the carrier is preferably from 10 to 90% by mass, more preferably from 20 to 85% by mass, and still more preferably from 30 to 80% by mass.

The content of SiO _{2 in} the carrier is preferably 0.05 to 16% by mass, more preferably 0.10 to 13% by mass, and even more preferably 0.15 to 8% by mass.

  The carrier may contain components other than the above-mentioned components A and B at a ratio of 20% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less, and still more preferably 2% by mass or less. Further, it is preferable that the carrier substantially comprises the A component and the B component. Here, “substantially” means that impurities and the like inevitably contained in the raw materials and the manufacturing process can be contained, but other substances are not contained.

<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 above-described carrier.
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 above-mentioned carrier and the active metal component in a proportion of 20% by mass or less, preferably 15% by mass or less, more preferably 10% by mass or less, and still more preferably 5% by mass or less. May be. In addition, it is preferable that the catalyst of the present invention substantially comprises the carrier and the active metal component. Here, “substantially” means that impurities and the like inevitably contained in the raw materials and the manufacturing process can be contained, but other substances are not contained.
Components other than the above-described carrier and active metal component include, for example, Cr, Fe, Co, Ni, Cu, Ag, Au, Pd, Nd, In, Sn and Ir.

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

FIG. 1 illustrates a schematic perspective view of a honeycomb 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) is a quadrangle. The size (diameter) of the cell (3) is the width of the aperture (5), the space between the cells (3) and (3) is the partition (7), and the thickness (9) of the partition (7) is the thickness. Also called. Further, the surface where the opening of the cell (3) is exposed is defined as an end surface (11), and the other surface is defined as a side surface (13). Further, the length in the longitudinal direction of the honeycomb structure is represented by X.

  As shown in FIG. 1, the catalyst of the present invention preferably has a partition (7) having a slit (15) of 0.005 mm or more and less than the cell opening width (5). Here, the width (17) of the slit is measured by observing the end face (11) of the honeycomb structure using a microscope, a microscope, or the like, and measuring the width at the end face (11). Shall mean.

Then, similarly, the number of slits obtained by observing and confirming the end face (11) of the honeycomb structure using a microscope or a microscope is the number of partitions (that is, the number of cells × (the number of cells−1) × It is preferably 0.03 to 3% (per one end face) with respect to 2), and more preferably 0.06 to 2%. If this ratio is too low, the initial performance tends to be low and the resistance to poisoning components tends to be low. Conversely, if the ratio is too high, there may be a problem in the strength of the catalyst or a problem in productivity (cannot produce a honeycomb-shaped shape).
When the number of cells on one side of the end face and the number of cells on the other side are the same, such as when the end face of the honeycomb structure is substantially square, the number of partition walls is equal to the number of cells as described above. × (number of cells−1) × 2. However, when the number of cells on one side of the end face is different from the number of cells on the other side, such as when the end face of the honeycomb structure is a rectangle, the number of partitions on the one side is X. , And Y is the number of cells on the other side, and is calculated from the equation X (Y-1) + Y (X-1). When the number of cells on one side and the number of cells on the other side of the end face of the honeycomb structure are the same, this equation corresponds to the case of X = Y, and therefore, as described above, the number of cells × (the number of cells) -1) It is the same as the case of calculating the number of partitions from × 2.

  Further, the maximum length of the slit 15 (that is, the depth of the slit in a direction substantially parallel to the longitudinal direction of the honeycomb structure) is 5 to 80% of the longitudinal length (X) of the honeycomb structure. And more preferably 5 to 70%. If this ratio is too low, the initial performance tends to be low and the resistance to poisoning components tends to be low. Conversely, if the ratio is too high, there may be a problem in the strength of the catalyst or a problem in productivity (cannot produce a honeycomb-shaped shape).

The catalyst of the present invention may have a compressive strength of 50 to 200 N / cm ² when the honeycomb catalyst has a cell thickness (9) of 0.50 mm and an opening width (5) of 3.20 mm. preferable. In such a case, the catalyst of the present invention is preferable because the compressive strength is sufficiently high.
The method for measuring the compressive strength will be described in detail in Examples described later.

  The catalyst of the present invention can be preferably used as an exhaust gas treatment catalyst for cement production exhaust gas, refuse 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) when the exhaust gas contains organic chlorinated compounds.

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

Next, a method for producing the catalyst of the present invention will be described.
In the catalyst of the present invention, the support can be produced by mixing two or more types of inorganic oxides having different shrinkage rates. For example, it can be manufactured by a method described in JP-A-2004-41893 or JP-A-2005-021780.
The catalyst of the present invention is obtained by mixing the carrier or the raw material thereof and the active metal component or the raw material thereof to obtain a mixture, 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 and supporting a carrier component and an active ingredient thereon.

The catalyst of the present invention is preferably produced by a production method comprising the following steps (a) to (c).
Step (a): A slurry containing Ti or a slurry containing Ti and at least one selected from the group consisting of W and Mo is dehydrated and calcined to obtain an inorganic single oxide raw material made of TiO ₂ , or at least one step of obtaining the inorganic composite oxide raw material of TiO ₂ selected from the group consisting of WO ₃ and MoO _3.
Step (b): A slurry containing Si or a slurry containing at least one selected from the group consisting of Ti and W and Si is dehydrated and calcined to obtain an inorganic single oxide raw material made of SiO ₂ , or A step of obtaining a raw material of an inorganic composite oxide of at least one selected from the group consisting of TiO ₂ and WO ₃ and SiO ₂ .
Step (c): mixing the inorganic single oxide raw material or inorganic composite oxide raw material obtained in step (a) with the inorganic single oxide raw material or inorganic composite oxide raw material obtained in step (b) Extruding into a honeycomb shape, forming, drying and firing.
Hereinafter, such a preferable production method is also referred to as a “production method of the present invention”.

<Production method of the present invention>
Step (a) will be described.
In the step (a), a slurry containing Ti or a slurry containing Ti and at least one selected from the group consisting of W and Mo is first obtained.
This slurry, for example, a compound containing Ti, a compound containing W, and a compound containing Mo are dissolved in a solvent such as water, and then the pH is adjusted with an acid or an alkali to thereby prepare an oxide of Ti, Further, it can be obtained by depositing an oxide of W and an oxide of Mo. After the precipitation, aging is preferably performed at 30 to 98 ° C for 0.5 to 12 hours.

  Here, the compound containing Ti is preferably metatitanic acid, and it is preferable to use a titanium sulfate solution obtained from a process for producing titanium dioxide by a sulfuric acid method and further hydrolyze the titanium sulfate to obtain metatitanic acid.

  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 include tungsten, tungsten dichloride, tungsten trichloride, tungsten tetrachloride, tungsten pentachloride, tungsten dichloride dioxide, and tungsten tetrachloride oxide.

  Examples of the compound 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, and molybdenum tetrachloride.

When a compound containing W is used in addition to a compound containing Ti, the quantitative ratio of the compound containing Ti to the compound containing W is not particularly limited, but TiO ₂ (a conversion value assuming that all of Ti is TiO ₂ ) ) all WO ₃ (W is converted value assuming that the WO ₃₎ that is preferably adjusted to be 1 to 15 parts by weight to 100 parts by weight.

When a compound containing Mo is used in addition to a compound containing Ti, the quantitative ratio between the compound containing Ti and the compound containing Mo is not particularly limited, but TiO ₂ (a conversion value assuming that all of Ti is TiO ₂ ) It is preferable to adjust MoO ₃ (converted value assuming that all of Mo is MoO ₃ ) to 1 to 15 parts by mass with respect to 100 parts by mass.

After obtaining the slurry as described above, it is dehydrated and fired.
The dehydration method is not particularly limited, and for example, dehydration can be performed by applying a conventionally known method, specifically, a centrifugal separation method or the like.
The firing method is not particularly limited, and for example, firing can be performed using a conventionally known method, specifically, using 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.
Before baking the cake obtained after dehydration, it may be dried. For drying, for example, a conventionally known method, specifically, an electric dryer or the like can be used. The drying temperature is, for example, 30 to 200 ° C.

Such step (a), the inorganic single oxide material consists of TiO ₂ or, can be obtained inorganic mixed oxide material of at least one of a TiO ₂ selected from the group consisting of WO ₃ and MoO ₃ .

Step (b) will be described.
In the step (b), first, a slurry containing Si or a slurry containing at least one selected from the group consisting of Ti and W and Si is obtained.
This slurry is prepared by dissolving or dispersing, for example, a compound containing Si, a compound containing Ti, and a compound containing W in a solvent such as water, and then adjusting the pH using an acid or an alkali to form an oxide of Si. Alternatively, it can be obtained by further depositing an oxide of Ti and an oxide of W. After the precipitation, aging is preferably performed at 30 to 98 ° C for 0.5 to 12 hours.

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

  As the compound containing Ti and the compound containing W, those similar to those in the step (a) can be used.

When a compound containing Ti is used in addition to a compound containing Si, the quantitative ratio between the compound containing Si and the compound containing Ti is not particularly limited. However, SiO ₂ (a conversion value assuming that all of Si is SiO ₂ ) ) it is preferred that all of the TiO ₂ (Ti is converted value assuming that the TiO ₂₎ is adjusted to be from 150 to 900 parts by weight to 100 parts by weight.

When a compound containing W is used in addition to a compound containing Si, the quantitative ratio between the compound containing Si and the compound containing W is not particularly limited. However, SiO ₂ (a conversion value assuming that all of Si is SiO ₂ ) ) all WO ₃ (W is converted value assuming that the WO ₃₎ that is preferably adjusted to be from 12.5 to 1500 parts by weight to 100 parts by weight.

After obtaining the slurry as described above, it is dehydrated and fired.
The dehydration method and firing method are not particularly limited, and may be the same as in the case of step (a). Further, a drying treatment may be performed as in the case of the step (a).

Such step (2), an inorganic single oxide material made of SiO ₂ or, can be obtained with at least one inorganic composite oxide raw material of SiO ₂ is selected from the group consisting of TiO ₂ and WO ₃ .

Step (c) will be described.
In the step (c), the inorganic single oxide raw material or the inorganic composite oxide raw material obtained in the step (a) (hereinafter also referred to as the raw material (a)) and the inorganic single oxide raw material obtained in the step (b) are used. A monoxide material or an inorganic composite oxide material (these materials are also referred to as a material (b) below) are mixed.
Although this mixing ratio is not particularly limited, the ratio of the raw material (a) to the total mass of the raw material (a) and the raw material (b) (mass of the raw material (a) / (mass of the raw material (a) + mass of the raw material (b)) ) × 100 (%)) is preferably 10 to 95% by mass and mixed after adding water.

  When the raw material (a) and the raw material (b) are mixed after adding water as described above, a molding aid may be further added and mixed as necessary. As the molding aid, for example, conventionally known ones can be used, and specific examples include polyethylene oxide, crystalline cellulose, organic substances such as glycerin and polyvinyl alcohol, and clay minerals.

Then, the obtained mixture is formed into a honeycomb shape using, for example, a conventionally known forming machine, and then dried and fired.
The drying method is not particularly limited, and for example, drying can be performed using a conventionally known method, specifically, an electric dryer or the like. The drying temperature is, for example, 30 to 200 ° C.
The firing method is not particularly limited, and for example, firing can be performed using a conventionally known method, specifically, using a firing furnace or the like. The firing temperature is, for example, 450 to 700 ° C.

  The catalyst of the present invention can be obtained by such a production method of the present invention.

  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)]
A metatitanic acid slurry (manufactured by Ishihara Sangyo Co., Ltd.) was charged into a stirrer equipped with a reflux condenser, 25 mass% aqueous ammonia was added so as to have a pH of 7.5 or more, and the mixture was heated and aged at 60 ° C. for 3 hours with sufficient stirring. . Then, the obtained slurry was dewatered and washed, and the dehydrated cake was dried at 110 ° C. and then fired at 500 ° C. to obtain a Ti oxide raw material.

[Raw material preparation 2 (Ti-Si raw material: TiO ₂ -20 mass% SiO ₂ composite oxide raw material)]
They were charged to metatitanic acid slurry (manufactured by Ishihara Sangyo Kaisha), a reflux condenser equipped with a stirrer, to which silica sol (JGC Catalysts and Chemicals Ltd., S-20L), and so SiO ₂ is 20 parts by mass with respect to TiO ₂ 100 parts by weight After the addition, 25 mass% ammonia water was added so as to have a pH of 7.5 or more, and the mixture was heated and aged at 60 ° C. for 3 hours with sufficient stirring.
Then, the obtained slurry was dewatered 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.

[Raw material preparation 3 (Ti-W-Si raw material: TiO ₂ -5 mass% WO ₃ -10% SiO ₂ composite oxide raw material)]
They were charged to metatitanic acid slurry (manufactured by Ishihara Sangyo Kaisha), a reflux condenser equipped with a stirrer, adding thereto ammonium paratungstate (produced by Nippon Shinkinzoku Co.), as WO ₃ with respect to TiO ₂ 100 parts by weight is 5 parts by weight Further, silica sol (manufactured by Nikki Shokubai Kasei Co., Ltd., S-20L) was added so that SiO ₂ was 10 parts by mass with respect to 100 parts by mass of TiO ₂ , and 25% by mass aqueous ammonia was added at pH 7.5 or more. Then, the mixture was heated and aged at 60 ° C. for 3 hours with sufficient stirring.
Then, the obtained slurry was dehydrated and washed, and the dehydrated cake was dried at 110 ° C and then baked at 500 ° C to obtain a Ti-W-Si composite oxide material.

[Raw material preparation 4 (Ti-Mo raw material: TiO ₂ -5 mass% MoO ₃ composite oxide raw material)]
A metatitanic acid slurry (manufactured by Ishihara Sangyo Co., Ltd.) was charged into a stirrer equipped with a reflux condenser, and ammonium paramolybdate was added to 100 parts by mass of TiO ₂ so that 5 parts by mass of MoO ₃ was added. After adding ammonia water so as to have a pH of 7.5 or more, the mixture was heated and aged at 60 ° C. for 3 hours with sufficient stirring.
Then, the obtained slurry was dewatered and washed, and the dehydrated cake was dried at 110 ° C and then fired at 500 ° C to obtain a Ti-Mo composite oxide raw material.

[Raw material preparation 5 (Ti-W raw material: TiO ₂ -5 mass% WO ₃ composite oxide raw material)]
They were charged to metatitanic acid slurry (manufactured by Ishihara Sangyo Kaisha), a reflux condenser equipped with a stirrer, adding thereto ammonium paratungstate (produced by Nippon Shinkinzoku Co.), as WO ₃ with respect to TiO ₂ 100 parts by weight is 5 parts by weight Then, 25 mass% ammonia water was added so as to have a pH of 7.5 or more, and the mixture was heated and aged at 60 ° C. for 3 hours with sufficient stirring.
Then, the obtained slurry was subjected to dehydration washing, and the dehydrated cake was dried at 110 ° C and fired at 500 ° C to obtain a Ti-W composite oxide raw material.

Preparation of catalyst [Comparative Example 1]
To 22.7 kg of the Ti oxide raw material obtained as described above, 1.285 kg of ammonium metavanadate (manufactured by Shinko Chemical Co., Ltd.), 920 g of ammonium paramolydate (manufactured by Taiyo Mining Co., Ltd.), and 2.10 kg of 25 mass% ammonia water Water, 125 g of polyethylene glycol (PEG-20,000 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 125 g of crystalline cellulose (Ceolas TG-101) were added, and the mixture was kneaded with a mixer so as to have a water concentration of 30% by mass. After drying at 60 ° C. for 72 hours, it was calcined at 500 ° C. for 3 hours to obtain a catalyst. The obtained honeycomb catalyst had a partition wall thickness of 0.50 mm, mesh size of 3.20 mm, and an outer shape of 75 mm.

[Comparative Example 2]
To 22.7 kg of the Ti-Si composite oxide raw material obtained as described above, 1.285 kg of ammonium metavanadate (manufactured by Shinko Chemical Co., Ltd.), 920 g of ammonium paramorinate (manufactured by Taiyo Mining Co., Ltd.), 25% by mass aqueous ammonia 2 .10 kg, water, 125 g of polyethylene glycol (PEG-20,000, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 125 g of crystalline cellulose (Seolas TG-101) were added, and the mixture was kneaded with a mixer so that the water concentration became 30% by mass. An attempt was made to obtain a sample by extruding into a honeycomb shape having a thickness of 0.50 mm, an opening of 3.20 mm, and an outer diameter of 75 mm. However, the honeycomb shape was not obtained, and a honeycomb sample could not be obtained.

[Comparative Example 3]
Similarly, 1.285 kg of ammonium metavanadate (manufactured by Shinko Chemical Co., Ltd.) and 1.28 kg of ammonium paravanadate (solar ore) were added to 1.29 kg of the Ti oxide raw material and 21.39 kg of the Ti-Si composite oxide raw material obtained as described above. 920 g, 2.30 kg of 25 mass% ammonia water and water, 125 g of polyethylene glycol (PEG-2000, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 125 g of crystalline cellulose (Ceolas TG-101) were added, and the water concentration was 30 mass%. After kneading, the mixture was extruded into a honeycomb shape having a partition wall thickness of 0.50 mm, a mesh size of 3.20 mm, and an outer diameter of 75 mm, dried at 60 ° C. for 72 hours, and calcined at 500 ° C. for 3 hours to obtain a catalyst.

[Example 1]
Similarly, 21.91 kg of the Ti oxide raw material and 0.773 kg of the Ti-Si composite oxide raw material obtained as described above are mixed with 1.285 kg of ammonium metavanadate (manufactured by Shinko Chemical Industry Co., Ltd.) 920 g, 2.30 kg of 25 mass% ammonia water and water, 125 g of polyethylene glycol (PEG-2000, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 125 g of crystalline cellulose (Ceolas TG-101) were added, and the water concentration was 30 mass%. After kneading, the mixture was extruded into a honeycomb shape having a partition wall thickness of 0.50 mm, a mesh size of 3.20 mm, and an outer diameter of 75 mm, dried at 60 ° C. for 72 hours, and calcined at 500 ° C. for 3 hours to obtain a catalyst.

[Example 2]
Similarly, a catalyst was obtained in the same manner as in Example 1, except that 12.37 kg of a Ti oxide raw material and 10.31 kg of a Ti-Si composite oxide raw material were used.

[Example 3]
Similarly, a catalyst was obtained in the same manner as in Example 1, except that 3.35 kg of the Ti oxide raw material and 19.33 kg of the Ti-Si composite oxide raw material were used.

[Example 4]
Similarly, a catalyst was obtained in the same manner as in Example 1, except that 5.93 kg of the Ti oxide raw material and 16.75 kg of the Ti-W-Si composite oxide raw material were used.

[Example 5]
Similarly, a catalyst was obtained in the same manner as in Example 1, except that 0.73 kg of the Ti—Si composite oxide raw material and 21.91 kg of the Ti—Mo composite oxide raw material were used.

[Example 6]
Similarly, a catalyst was obtained in the same manner as in Example 1, except that 0.73 kg of the Ti—Si composite oxide raw material and 21.91 kg of the Ti—W composite oxide raw material were used.

[Example 7]
Similarly, to 13.66 kg of the Ti oxide raw material and 10.31 kg of the Ti—Si composite oxide raw material obtained as described above, 4.53 kg of a 50% by mass aqueous solution of manganese nitrate, and 920 g of ammonium paramorinate (manufactured by Taiyo Mining Co., Ltd.) And 2.30 kg of 25% by mass aqueous ammonia, water, 125 g of polyethylene glycol (PEG-20,000 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 125 g of crystalline cellulose (Ceolas TG-101) were added so that the water concentration became 30% by mass. After kneading, the mixture was extruded into a honeycomb shape having a partition wall thickness of 0.50 mm, a mesh size of 3.20 mm, and an outer diameter of 75 mm, dried at 60 ° C for 72 hours, and calcined at 500 ° C for 3 hours to obtain a catalyst.

Example 8
Similarly, 1.285 kg of ammonium metavanadate (manufactured by Shinko Chemical Co., Ltd.) and lanthanum nitrate hexahydrate were added to 13.66 kg of the Ti oxide raw material and 10.31 kg of the Ti-Si composite oxide raw material obtained as described above. 2.03 kg, 2.30 kg of 25 mass% ammonia water and water, 125 g of polyethylene glycol (PEG-20,000 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 125 g of crystalline cellulose (Ceolas TG-101) were added to reduce the water concentration to 30 mass%. After kneading, the mixture was extruded into a honeycomb shape having a partition wall thickness of 0.50 mm, a mesh size of 3.20 mm, and an outer diameter of 75 mm, dried at 60 ° C. for 72 hours, and calcined at 500 ° C. for 3 hours to obtain a catalyst.

[Example 9]
Similarly, to 13.66 kg of the Ti oxide raw material and 10.31 kg of the Ti—Si composite oxide raw material obtained as described above, 1.285 kg of ammonium metavanadate (manufactured by Shinko Chemical Industry Co., Ltd.) and yttrium nitrate hexahydrate 2.57 kg, 2.30 kg of 25 mass% ammonia water, water, 125 g of polyethylene glycol (PEG-2000, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 125 g of crystalline cellulose (Ceolas TG-101) were added to reduce the water concentration to 30 mass%. After kneading, the mixture was extruded into a honeycomb shape having a partition wall thickness of 0.50 mm, a mesh size of 3.20 mm, and an outer diameter of 75 mm, dried at 60 ° C. for 72 hours, and calcined at 500 ° C. for 3 hours to obtain a catalyst.

[Example 10]
Similarly, to 13.66 kg of the Ti oxide raw material and 10.31 kg of the Ti—Si composite oxide raw material obtained as described above, 1.285 kg of ammonium metavanadate (manufactured by Shinko Chemical Industry Co., Ltd.) and cerous nitrate hexahydrate 2.53 kg of a Japanese product, 2.30 kg of 25% by mass ammonia water and water, 125 g of polyethylene glycol (PEG-20,000 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 125 g of crystalline cellulose (Ceolas TG-101) were added, and the water concentration was 30 mass. %, Then extruded into a honeycomb shape having a partition wall thickness of 0.50 mm, a mesh size of 3.20 mm, and an outer diameter of 75 mm, dried at 60 ° C. for 72 hours, and calcined at 500 ° C. for 3 hours to obtain a catalyst.

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

[Comparative Example 5]
Similarly, 1.285 kg of ammonium metavanadate (manufactured by Shinko Chemical Industry Co., Ltd.) and ammonium paravanadate (solar mineral) were added to 0.52 kg of the Ti oxide raw material and 22.16 kg of the Ti-Si composite oxide raw material obtained as described above. 920 g, 2.30 kg of 25 mass% ammonia water and water, 125 g of polyethylene glycol (PEG-2000, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 125 g of crystalline cellulose (Ceolas TG-101) were added, and the water concentration was 30 mass%. After extruding into a honeycomb shape having a partition wall thickness of 0.50 mm, a mesh size of 3.20 mm, and an outer diameter of 75 mm, drying at 85 ° C. for 48 hours, and calcining at 500 ° C. for 3 hours to obtain a catalyst.

[Comparative Example 6]
Similarly, 1.285 kg of ammonium metavanadate (manufactured by Shinko Chemical Industry Co., Ltd.) and ammonium paravanadate (solar mineral) were added to 0.52 kg of the Ti oxide raw material and 22.16 kg of the Ti-Si composite oxide raw material obtained as described above. 920 g, 2.30 kg of 25 mass% ammonia water and water, 125 g of polyethylene glycol (PEG-2000, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 125 g of crystalline cellulose (Ceolas TG-101) were added, and the water concentration was 30 mass%. After extruding into a honeycomb shape with a partition wall thickness of 0.50 mm, a mesh size of 3.20 mm, and an outer diameter of 75 mm, hot air at 60 ° C is passed through the honeycomb holes, dried for 48 hours, and fired at 500 ° C for 3 hours. A catalyst was obtained.

[Test Example 1] Estimation of specific surface area derived from slits by BET specific surface area measurement and mercury porosimeter specific surface area measurement For each of the catalysts obtained in the examples and comparative examples, the BET specific surface area measurement value and the fineness of 5 nm to 5 µm using a mercury porosimeter were measured. The measured specific surface area occupied by the pores was compared. Since the specific surface area SA _BET according to the BET method is a value of the specific surface area formed by all the small and large pores and slits, the measured value of the specific surface area SA _Hg occupied by the pores of 5 nm to 5 μm by the mercury porosimeter is subtracted from this value. The value thus obtained is a value that correlates with the specific surface area of the slit, and is an index indicating that the slit is uniformly distributed on the catalyst surface.
The BET specific surface area measurement and the mercury porosimeter specific surface area measurement were performed under the following conditions.
BET specific surface area measuring device: Mountech HM model-1220
BET specific surface area measurement condition: Pretreatment 300 ° C for 1 hour, BET single point method Mercury porosimeter specific surface area measurement 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

Table 1 shows the measured BET specific surface area (SA _BET ) and the measured specific surface area (SA _Hg ) occupied by pores of 5 nm to 5 μm in mercury porosimeter specific surface area measurement. The value of SA _BET -SA _Hg was in the range of 25-35 for the catalysts of Examples 1-8. On the other hand, in the case of the catalysts of Comparative Examples 1 to 6, the values were out of this range. Further, it can be said that the slits in the catalysts of Examples 1 to 8 are not only distributed on a part of the catalyst surface but are uniformly distributed.

[Test Example 2] Measurement of slit ratio A microscope was inserted into all the through holes, and the number of slits of the partition wall having a width of 0.005 mm or more and a cell opening (3.2 mm) or less at a honeycomb end face was counted. (Overlapping slits between adjacent through-holes are considered identical).

Next, the ratio (percentage) to the number of partition walls (20 cells × (20 cells−1) × 2 = 760) was determined.
The results are shown in Table 1.
As shown in Table 1, in the case of the catalysts of Examples 1 to 8, the slit ratio (that is, the number of slits / the number of partition walls × 100) was in the range of 0.03 to 3% (per one end face).

[Test Example 3] Measurement of slit length A microscope was inserted into the through hole, the slit length was measured, and the maximum value was defined as the slit length.

[Test Example 4] Compressive strength measurement The catalyst obtained in each of Examples 1 to 8 and Comparative Examples 1 to 6 was cut into a length of 75 mm, cut into a cube having a size of 75 mm x 75 mm, and then cut as shown in FIG. As shown in Table 2, the sample was compressed in a direction perpendicular to the catalyst through-hole, and the pressure when the catalyst was completely destroyed was measured.
The results are shown in Table 1. In the case of the catalysts of Examples 1 to 8, the compressive strength was in the range of 50 to 200 N / cm ² . That is, it was confirmed that the honeycomb catalyst had high compressive strength.

[Test Example 5] Accelerated deterioration test of catalyst by spraying CaCl ₂ solution and ammonium sulfate Each catalyst obtained in Examples and Comparative Examples was cut into 4 × 4 × 107 mmL (wall thickness: 0.50 mm, opening of mesh). (Width: 3.20 mm) After setting in a quartz reaction tube, the catalytic denitration performance in a fresh state was measured. Here, the denitration rate of nitrogen oxides (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 Abatec Yanaco Co., Ltd.).
DeNOx rate (%) = {(NOx in non-contact gas (volume ppm) −NOx in gas after contact (volume ppm)) / NOx in non-contact gas (volume ppm)} × 100
The initial denitration rate determined 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 at a distance of 300 mm 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. From the η (%), k = −AV × ln (1−η / 100) was calculated from the denitration rate after deterioration obtained here. Then, k / k ₀ was obtained and compared with the performance in the Fresh state. Performance measurement and CaCl ₂ solution spraying were both 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 vol%, H ₂ O = 10 vol%, N ₂ = balance Accelerated deterioration test condition 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 (ppm by volume), O ₂ = 7% by volume, H ₂ O = 10% by volume (as CaCl ₂ solution), N ₂ = balance

The results are shown in Table 1. It can be seen that the catalysts of Examples 1 to 8 have higher activities even after spraying the CaCl ₂ solution than the catalysts of Comparative Examples 1 to 6.

Test Example 6 Low-Temperature Denitrification Test Each catalyst obtained in Examples and Comparative Examples was cut into 4 × 4 × 107 mmL (thickness: 0.50 mm, opening width: 3.20 mm), and a quartz reaction was performed. After setting in a tube, the low-temperature denitration performance was measured.
Here denitration of nitrogen oxides in the gas before and after the catalyst contact (NO _X) was determined by the above equation. At this time, the concentration of NO _X was measured with a chemiluminescent nitrogen oxide analyzer (ECL-88AO, manufactured by Anatech Yanaco).

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

  The results are shown in Table 1. In Table 1, those having a low-temperature denitration performance of 65% or more were marked as good (○) and those with less than 65% were marked as poor (x).

As shown in Table 1, in the catalysts of Examples 1 to 10, the value of SA _BET -SA _Hg was in the range of 25 to 35, and the value of the number of slits / the number of partition walls × 100 was 0.03 to 3% ( (Per one end face), the slit length is in the range of 5 to 80% with respect to the longitudinal direction of the honeycomb catalyst, the compressive strength is in the range of 50 to 200 N / cm ² , and after spraying the CaCl ₂ solution. Was found to have high activity and low temperature denitration performance.

On the other hand, in Comparative Examples 1 and 4 in which the component B was not contained, the value of SA _BET -SA _Hg was low, and no slit was formed. In Comparative Examples 1 and 4, the activity after spraying the CaCl ₂ solution was low.
Further, Comparative Example 2, which is an embodiment containing no component A, was poor in molding state (productivity), and collapsed due to insufficient strength of the obtained molded body, and became a honeycomb-shaped catalyst.
In Comparative Example 3, in which the ratio of component A to component B was 5:83 and the content of SiO _{2 in} the catalyst exceeded 16% by mass, the value of SA _BET -SA _Hg was high, and the compressive strength was high. Became lower. The same tendency was observed in Comparative Examples 5 and 6.

Claims (7)

An exhaust gas treatment honeycomb catalyst comprising a carrier comprising a mixture of an A component and a B component, and an active metal component,
Wherein component A, an inorganic single oxides consisting TiO _2, or an inorganic composite oxide of at least one and TiO ₂ selected from the group consisting of WO ₃ and MoO _3,
The B component is an inorganic single oxides consisting SiO _2, or at least one inorganic composite oxide of SiO ₂ selected from the group consisting of TiO ₂ and WO _3,
The content of the component A is 10 to 90% by mass,
The content of SiO ₂ is 0.05 to 16% by mass;
1 hour at 300 ° C., BET method in which after the pretreatment with specific surface area according to (single point method) (SA _BET), 1 hour at 300 ° C., after pretreatment, the mercury penetration angle of 130 degrees, the surface tension 473erg / cm ² Exhaust gas treatment characterized in that the difference (SA _BET -SA _Hg ) from the specific surface area (SA _Hg ) of the catalyst pores of 5 nm to 5 μm by mercury intrusion porosimetry performed in the range of 25 to 35 m ² / g. Honeycomb catalyst. The partition has a slit of 0.005 mm or more and less than the cell opening width, and the number of slits is the number of partitions (X is the number of cells on one side of the end face of the rectangular honeycomb structure, and X is the number of cells on the other side. 2. The exhaust gas treatment honeycomb catalyst according to claim 1, wherein Y is 0.03 to 3% (per one end surface) based on X (Y−1) + Y (X−1)). The exhaust gas treatment honeycomb catalyst according to claim 2 , wherein a maximum length of the slit is 5 to 80% of a length in a longitudinal direction. The exhaust gas according to any one of claims 1 to 3 , wherein the honeycomb cell has a honeycomb cell having a thickness of 0.50 mm and an opening width of 3.20 mm, and has a compressive strength of 50 to 200 N / cm ^2. Treated honeycomb catalyst. The solids content of the SiO ₂ contained in the component B is 5 to 20 wt%, the exhaust gas treatment honeycomb catalyst according to any one of claims 1-4. The exhaust gas treatment honeycomb catalyst according to any one of claims 1 to 5 , wherein the active metal component is at least one selected from the group consisting of vanadium, molybdenum, manganese, lanthanum, yttrium, and cerium. A method for producing an exhaust gas treating honeycomb catalyst, comprising the following steps (a) to (c), wherein the exhaust gas treating honeycomb catalyst according to any one of claims 1 to 6 is obtained.
Step (a): A slurry containing Ti or a slurry containing Ti and at least one selected from the group consisting of W and Mo is dehydrated and calcined to obtain an inorganic single oxide raw material made of TiO ₂ , or at least one step of obtaining the inorganic composite oxide raw material of TiO ₂ selected from the group consisting of WO ₃ and MoO _3.
Step (b): A slurry containing Si or a slurry containing at least one selected from the group consisting of Ti and W and Si is dehydrated and calcined to obtain an inorganic single oxide raw material made of SiO ₂ , or A step of obtaining a raw material of an inorganic composite oxide of at least one selected from the group consisting of TiO ₂ and WO ₃ and SiO ₂ .
Step (c): mixing the inorganic single oxide raw material or inorganic composite oxide raw material obtained in step (a) with the inorganic single oxide raw material or inorganic composite oxide raw material obtained in step (b) Extruding into a honeycomb shape, forming, drying and firing.