Modified titanium oxide particle and its manufacturing method and exhaust gas treating catalyst using the same

The present invention relates to modified titanium oxide particles and a method for producing the same, and a catalyst for treating exhaust gas using the modified titanium oxide particles. Modified titanium oxide particles suitable for use as a catalyst for exhaust gas treatment used for treating nitrogen oxides (hereinafter sometimes abbreviated as NOx) contained in exhaust gas discharged from a combustion furnace of a factory and the like. The present invention relates to the production method thereof and a catalyst for treating exhaust gas using the modified titanium oxide particles.

Conventionally, as an exhaust gas treatment catalyst (hereinafter sometimes abbreviated as a denitration catalyst) that removes NOx in combustion exhaust gas by using a reducing agent such as ammonia, a carrier made of titanium oxide, tungsten oxide, and vanadium oxide are generally used. Catalysts carrying active ingredients such as these are industrially used. Exhaust gas emitted from combustion furnaces contains sulfur compounds (hereinafter sometimes abbreviated as SOx) in addition to nitrogen oxides, and SO is the majority of SOx.₂Is partially oxidized on the denitration catalyst and SO₃And this SO₃Combines with the unreacted component of ammonia used as a reducing agent to generate acidic ammonium sulfate, which causes blockage of equipment such as wake heat exchangers.₃There was a problem that the device itself would corrode the equipment. Therefore, the denitration catalyst has high denitration activity and SO.₂Performance with a low oxidation rate is required.

SO mentioned above₃As a denitration catalyst that suppresses the ability to oxidize to, Patent Document 1 describes a denitration catalyst that adds ammonia to the exhaust gas and catalytically reduces and removes nitrogen oxides in the exhaust gas, and the lower layer portion has denitration performance. Disclosed is a denitration catalyst characterized by having a two-layer structure composed of a catalyst component having a component and coated with a component having a small ability to convert sulfur dioxide in exhaust gas into sulfur trioxide even if vanadium permeates the upper layer. In addition, components such as silica, zirconia, ZSM-5, silicalite and metallosilicate are shown as upper layer components. However, these upper layers are SO₂Since the oxidation rate is suppressed and the denitration activity is also suppressed, the catalyst has a problem of low denitration activity.

On the other hand, in Patent Document 2, as a method for producing a denitration catalyst capable of recovering the activity of the denitration catalyst whose activity has decreased, an aqueous solution of peroxotitanate or an aqueous solution of titanium sulfate and a hydrogen peroxide solution in which an active ingredient coexists are used. A method for producing a denitration catalyst, which comprises applying an aqueous solution obtained by mixing to the surface of a base material, then drying and firing, is disclosed, and the catalyst of the production method is only a peroxytitanate aqueous solution. It is described that the denitration activity is higher than that of the denitration catalyst obtained from. But SO₂There is no description about the suppression of the oxidation rate.

<patcit num="1"><text>Japanese Patent Application Laid-Open No. 08-196904</text></patcit><patcit num="2"><text>Japanese Patent Application Laid-Open No. 2005-313161</text></patcit>

<p> A first object of the present invention is modified titanium oxide suitable for use as an exhaust gas treatment catalyst for removing exhaust gas containing NOx and SOx discharged from a combustion furnace or the like by using a reducing agent such as ammonia. The point is to provide particles and a method for producing the particles. A second object of the present invention is to solve the above-mentioned problems, have high denitration activity, and SO.₂The point is to provide a catalyst for exhaust gas treatment having a low oxidation rate and excellent durability.</p>

<p> According to the present inventor, the reduction reaction of NOx depends on the outer surface area of the catalyst (sometimes called a surface reaction), and SO.₂As a result of diligent research, focusing on the fact that the oxidation reaction of the catalyst depends on the volume of the catalyst (sometimes called bulk reaction), SO₂WO on a carrier using titanium oxide particles in which the surface of titanium oxide particles containing silica and / or zirconia having an oxidation-suppressing effect is coated with titanium oxide produced from peroxotitanic acid.₃And / or V₂O₅The exhaust gas treatment catalyst that carries the above shows high denitration activity and SO.₂We have found that the oxidation rate is low and the durability is excellent, and have completed the present invention.</p><p> That is, in the first aspect of the present invention, the surface of titanium oxide particles (A) containing silica and / or zirconia is peroxotitanic acid (TiO).₃The modified titanium oxide particles are characterized by being coated with (hydrated). The second aspect of the present invention is that the amount of peroxotitanic acid coated is an oxide (TiO).₂) The modified titanium oxide particles according to claim 1, wherein the particles are in the range of 5 to 50 wt%. The third aspect of the present invention is SiO.₂And / or ZrO₂The modified titanium oxide particles according to claim 1 or 2, wherein the content is in the range of 0.5 to 20 wt% when the total amount of particles as an oxide is 100 wt%. The fourth aspect of the present invention is to (1) suspend silica and / or zirconia-containing titanium oxide particles (A) calcined in a temperature range of 400 to 700 ° C in water, and (2) hydrogen peroxide to titanium oxide particles. H for titanium oxide in (A)₂O₂/ TiO₂A silica and / or zirconia-containing titanium oxide particle-dispersed slurry (B) was prepared by peroxotitanium-oxidizing the surface of the titanium oxide particles (A) by adding a molar ratio in the range of 0.5 / 1 to 2/1. 3) Separately, add hydrogen peroxide to the titanium sulfate solution.₂O₂/ TiO₂A peroxotitanate solution (C) was prepared by adding in a molar ratio of 0.5 / 1 to 2/1, and (4) the titanium oxide particle dispersion slurry (B) and the peroxotitanate solution (C) were mixed. The surface of the titanium oxide particles (A) was adjusted by adding aqueous ammonia while controlling the temperature range of 55 ° C or less while stirring the obtained mixture slurry to adjust the pH of the mixture slurry to the range of 7 to 8. Peroxotitanic acid is deposited therein and then aged, dehydrated and washed to form a gel, or the gel is dried at a temperature of 150 ° C. or less, according to claims 1 to 3. The method for producing the modified titanium oxide particles according to any one of the above. A fifth aspect of the present invention relates to the method for producing modified titanium oxide particles according to claim 4, wherein the average particle size of the titanium oxide particles (A) is in the range of 0.2 to 5.0 μm. A sixth aspect of the present invention is to use WO as a carrier composed of the modified titanium oxide particles according to any one of claims 1 to 3.₃And / or V₂O₅The present invention relates to a catalyst for treating exhaust gas, which is characterized by carrying the above.</p><p> In the modified titanium oxide particles of the present invention, the central portion of the particles is composed of titanium oxide particles containing silica and / or zirconia, and the surface portion of the titanium oxide particles is composed of peroxotitanic acid. Therefore, when the modified titanium oxide particles are used as a raw material for an exhaust gas treatment catalyst that removes exhaust gas containing NOx and SOx discharged from a combustion furnace or the like by using a reducing agent such as ammonia, high denitration activity is achieved. And also SO₂An exhaust gas treatment catalyst having a low oxidation rate can be obtained. In addition to silica and / or zirconia, the modified titanium oxide particles contain oxides of elements such as tungsten, molybdenum, manganese, copper, tin, barium, cerium, phosphorus, and sulfur, that is, inorganic oxides. May be good. In particular, silicon oxide-tungsten oxide-titanium oxide system (SiO)₂-WO₃-TiO₂System) and Zirconium Oxide-Tungsten Oxide-Titanium Oxide (ZrO)₂-WO₃-TiO₂The ternary composite oxide of the system) is tungsten oxide (WO).₃) Is titanium oxide (TiO₂) Is preferable because it has an action and effect such as suppressing crystal growth.</p><p> In the modified titanium oxide particles, the amount of peroxotitanic acid is preferably in the range of 5 to 50 wt%, particularly 10 to 40 wt% based on the oxide. The amount of peroxotitanic acid in the present invention means coated peroxotitanate from a peroxotitanic acid solution. That is, the surface of the titanium oxide particles (A) is peroxotitanium-oxidized by hydrogen peroxide in the step (2) of the fourth invention, but it should be included in 5 to 50 wt% of the peroxotitanic acid. Instead, it is wt% for only the coated peroxotitanic acid obtained from the layer obtained by depositing the peroxotitanic acid solution on the surface of the titanium oxide particles by the step (4). In the case of a catalyst for exhaust gas treatment using modified titanium oxide particles in which the amount of peroxotitanic acid is less than 5 wt% on an oxide basis, SO₂Although the oxidation rate is low, high denitration activity may not be obtained. Further, in the case of a catalyst for exhaust gas treatment using modified titanium oxide particles in which the amount of peroxotitanic acid is more than 50 wt% on an oxide basis, the denitration activity is high, but SO.₂The oxidation rate may also be high, and the mechanical strength of the catalyst is weakened.</p><p> The modified titanium oxide particles are silica (SO).₂) And / or zirconia (ZrO)₂) The content is preferably in the range of 0.5 to 20 wt%, particularly 1 to 15 wt% when the total amount of particles as an oxide is 100 wt%. SO for exhaust gas treatment catalysts using modified titanium oxide particles with less than 0.5 wt% silica and / or zirconia content₂Oxidation rate may be high. In the case of a catalyst for exhaust gas treatment using modified titanium oxide particles having a silica and / or zirconia content of more than 20 wt%, SO₂The oxidation rate is low, but the denitration activity may also be low.</p><p> Next, the method for producing the modified titanium oxide particles described above will be described. (1) Regarding the step of suspending the silica and / or zirconia-containing titanium oxide particles (A) calcined in a temperature range of 400 to 700 ° C in water, (a) the silica and / or zirconia-containing oxidation in the present invention. Titanium particles (A) are prepared by a known method. For example, soluble titanium compounds such as inorganic titanium compounds such as titanium chloride and titanium sulfate and organic titanium compounds such as titanium oxalate and tetraisopropyl titanate, soluble silicon compounds such as silicon tetrachloride, ethyl silicate and methyl silicate, silica sol and / or After mixing a mixed aqueous solution with a soluble zirconium compound such as zirconium sulfate and zirconium chloride at a predetermined ratio, a well-known basic aqueous solution such as ammonia water, caustic soda aqueous solution, urea aqueous solution, and amine aqueous solution is added to the mixed aqueous solution. The compound hydroxide slurry is prepared by mixing, and the composite hydroxide or composite oxide obtained by aging, washing, and drying is calcined by a conventional method to obtain silica and / or zirconia-containing oxidation. Obtain titanium particles (A).</p><p>(B) The above-mentioned composite hydroxide or composite oxide obtained by drying is calcined in a temperature range of 400 to 700 ° C. When the firing temperature of the composite hydroxide or composite oxide is lower than 400 ° C, the catalyst for exhaust gas treatment using the modified titanium oxide particles obtained from the titanium oxide particles (A) has a weak compressive strength. In addition, the catalyst may not be processed into molded bodies such as honeycombs, pellets, and rings. When the firing temperature is higher than 700 ° C, the exhaust gas treatment catalyst using the modified titanium oxide particles obtained from the titanium oxide particles (A) is SO.₂Oxidation rate may be high. The titanium oxide particles (A) are preferably calcined in a temperature range of 450 to 650 ° C. The titanium oxide particles (A) described above preferably have an average particle size in the range of 0.2 to 5.0 μm. When the average particle size of the titanium oxide particles (A) is smaller than 0.2 μm, the compression strength of the exhaust gas treatment catalyst using the modified titanium oxide particles obtained from the titanium oxide particles (A) is weakened. There is. On the other hand, when the average particle size of the titanium oxide particles (A) is larger than 5.0 μm, the exhaust gas treatment catalyst using the modified titanium oxide particles obtained from the titanium oxide particles (A) has low denitration performance. , SO₂In addition to the high oxidation rate, it may not be possible to process the catalyst into molded products such as honeycombs, pellets, and rings. More preferably, the titanium oxide particles (A) have an average particle size in the range of 0.5 to 3.0 μm.</p><p>(C) The silica and / or zirconia-containing titanium oxide particles (A) calcined in the above-mentioned temperature range of 400 to 700 ° C have an appropriate concentration, preferably that the suspension can be easily stirred and uniformly mixed. Suspend in water in the range of 10-40 wt%.</p><p>(2) Hydrogen peroxide is added to the titanium oxide of the titanium oxide particles (A).₂O₂/ TiO₂Regarding the step of preparing a silica and / or zirconia-containing titanium oxide particle-dispersed slurry (B) in which the surface of the titanium oxide particles (A) is peroxotitanium-oxidized by adding the molar ratio in the range of 0.5 / 1 to 2/1. When peroxotitanic acid is deposited on the surface of the titanium oxide particles (A), a part of the surface of the titanium oxide particles (A) is subjected to hydrogen peroxide (H).₂O₂It is important to modify once with). When the surface of the titanium oxide particles (A) is once modified with hydrogen peroxide, mixed with the peroxotitanic acid solution (C) described later, and further added with aqueous ammonia, the titanium oxide particles (A) Peroxotitanic acid can be uniformly deposited on the surface. When the surface of the titanium oxide particles (A) is not modified with hydrogen peroxide, but mixed with the titanium acid solution (C) and then aqueous ammonia is added, peroxotitanium is added to the surface of the titanium oxide particles (A). The acid is not deposited and peroxotitanate particles may be formed.</p><p> H when the surface of the titanium oxide particles (A) is once modified with hydrogen peroxide₂O₂/ TiO₂The molar ratio shall be in the range of 0.5 / 1 to 2/1. The H₂O₂/ TiO₂When the molar ratio is less than 0.5 / 1, the peroxotitanic acid cannot be deposited on the surface of the titanium oxide particles (A), and peroxotitanate particles may be formed. On the other hand, H₂O₂/ TiO₂When the molar ratio exceeds 2/1, the exhaust gas treatment catalyst using the obtained modified titanium oxide particles has extremely weak compression strength, and the obtained modified titanium oxide particles are used as honeycombs, pellets, rings, etc. It may not be possible to process the molded body of.</p><p>(3) Separately, add hydrogen peroxide to the titanyl sulfate solution.₂O₂/ TiO₂Regarding the step of preparing the peroxotitanic acid solution (C) by adding the molar ratio in the range of 0.5 / 1 to 2/1, the concentration of the titanyl sulfate solution is arbitrarily adjusted, but is preferably an oxide (TiO).₂), It is desirable that it is in the range of 3 to 15 wt%. The amount of hydrogen peroxide added to the titanyl sulfate solution is H.₂O₂/ TiO₂If the molar ratio is less than 0.5 / 1, a peroxotitanic acid solution may not be obtained, and H₂O₂/ TiO₂When the molar ratio exceeds 2/1, the exhaust gas treatment catalyst using the obtained modified titanium oxide particles has extremely weak compressive strength, and the obtained modified titanium oxide particles are used as honeycombs, pellets, or rings. It may not be possible to process into a molded body such as. H of hydrogen peroxide added to titanyl sulfate solution₂O₂/ TiO₂The molar ratio is particularly preferably in the range of 1/1 to 2/1.</p><p>(4) The titanium oxide particle dispersion slurry (B) and the peroxotitanic acid solution (C) are mixed, and ammonia water is added to the obtained mixture slurry under stirring while controlling the temperature range to 55 ° C. or lower. The pH of the mixture slurry was adjusted to the range of 7 to 8 to deposit peroxotitanic acid on the surface of the titanium oxide particles (A), and then aged, dehydrated and washed to form a gel, or the same. For the step of drying the gel at a temperature of 150 ° C. or lower, the mixture of the titanium oxide particle dispersion slurry (B) described above and the peroxotitanic acid solution (C) described above is preferably from the peroxotitanic acid solution (C). The amount of peroxotitanic acid in the oxide (TiO₂) Is preferably in the range of 5 to 50 wt%, more preferably in the range of 10 to 40 wt%. If the temperature at which aqueous ammonia is added to the mixture slurry obtained by mixing as described above exceeds 55 ° C, peroxotitanic acid may not be obtained. In addition, the production ratio of peroxotitanic acid tends to decrease except when the pH of the mixture slurry is in the range of 7 to 8. Then, the pH-adjusted slurry is aged for 1 to 15 hours, and then dehydrated and washed by a well-known method to obtain a gel-like product. The gel is optionally dried at a temperature of 150 ° C. or lower. The effect of using peroxotitanic acid may not be obtained if it is dried at a temperature higher than 150 ° C.</p><p> The catalyst for exhaust gas treatment of the present invention is prepared by using WO on a carrier made of the above-mentioned modified titanium oxide particles.₃And / or V₂O₅To carry. The catalyst for exhaust gas treatment of the present invention contains 70 to 99.9% by weight of the above-mentioned modified titanium oxide particles, and WO as an active ingredient.₃And / or V₂O₅Is preferably contained in a proportion of 0.1 to 15% by weight. WO₃And / or V₂O₅If the proportion is less than 0.1% by weight, the desired denitrification activity may not be obtained, and if it is more than 15% by weight, SO₂Oxidizing activity may be high. Preferably, the above-mentioned modified titanium oxide particles are 80 to 99.5% by weight, WO.₃And / or V₂O₅Is preferably in the range of 0.5 to 10% by weight.</p><p> The catalyst for exhaust gas treatment is, for example, WO such as ammon paratungstate, ammon metatungstate, and ammonium metavanadate in addition to the above-mentioned modified titanium oxide particles.₃And V₂O₅Add the solution of the precursor of the above, clay, glass fiber, plasticizer, etc., knead and knead, mold into a desired shape such as a honeycomb shape, dry, and bake at 300 to 800 ° C to manufacture. Can be done. Further, clay, glass fiber, a plasticizer, etc. are added to the above-mentioned modified titanium oxide particles, kneaded and kneaded, molded into a desired shape, dried, and fired to obtain WO.₃And / or V₂O₅It can be produced by supporting a solution of the precursor of the above by a well-known supporting method such as an impregnation method.</p>

<p> In the modified titanium oxide particles of the present invention, the central portion of the particles is titanium oxide particles containing silica and / or zirconia, and the surface portion of the titanium oxide particles is made of peroxotitanic acid. Therefore, in the titanium oxide particles obtained by firing the modified titanium oxide particles, the central portion of the particles is made of titanium oxide containing silica and / or zirconia, and the surface portion of the particles is made of only titanium oxide. Therefore, when the modified titanium oxide particles are used as a raw material for a treatment catalyst that removes exhaust gas containing NOx and SOx discharged from a combustion furnace or the like by using a reducing agent such as ammonia, the central portion of the particles. Because it is titanium oxide containing silica and / or zirconia, it is a bulk reaction SO₂Oxidation rate is suppressed. On the other hand, since the surface portion of the modified titanium oxide particles is coated with peroxotitanic acid, WO is an active ingredient.₃And / or V₂O₅The denitration reaction, which is a surface reaction, exhibits high activity because it is highly dispersed and supported on the surface portion of the particles.</p>

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 (see FIGS. 1 and 2) Metatitanic acid slurry [TiO₂Concentration 30 wt%, manufactured by Ishihara Sangyo Co., Ltd.] 58.77 kg, silica sol [SiO₂A concentration of 20 wt% and a trade name of "Cataloid S-20L" manufactured by Catalytic Chemical Industry Co., Ltd.] 2.00 kg was added and mixed for 10 minutes, and then 15 wt% aqueous ammonia was added to adjust the pH of the slurry to 9.0. Next, the slurry was warmed and aged for 1 hour while adding 15 wt% aqueous ammonia so as to maintain pH 8.5 to 9.5 at a temperature of 70 ° C., the slurry was dehydrated and washed, and dried at 110 ° C. for 12 hours. Then, it was calcined at 520 ° C. for 5 hours, and the obtained calcined product was pulverized to obtain a binary composite oxide powder (a-1) having an average particle size of 0.8 μm. Reslurry 15.39 kg of this powder (a-1) into 35.91 kg of water, and add 35 wt% hydrogen peroxide solution to it.₂O₂/ TiO₂Titanium oxide containing silica obtained by peroxotitanium-oxidizing a part of the surface portion of the powder (a-1) after adding and mixing at 40 ° C for 30 minutes so that the molar ratio becomes 1 = 1. A particle dispersion slurry (a-2) was prepared. Next, titanyl sulfate crystal [TiO₂Concentration 32 wt%, manufactured by TAYCA CORPORATION] A 35 wt% hydrogen peroxide solution is added to an aqueous solution of titanyl sulfate diluted by dissolving 5.34 kg in 21.38 kg of water.₂O₂/ TiO₂A peroxotitanic acid solution (b-1) was obtained by adding and mixing in 1 minute so that the molar ratio was 1. Next, the titanium oxide particle dispersion slurry (a-2) was added and mixed with the peroxotitanic acid solution (b-1) at a ratio of 1: 9 (oxide conversion ratio) for 30 minutes with stirring, and then 15 wt%. Ammonia water was added to adjust the pH of the slurry to 7.5, and then the slurry was aged at a temperature of 50 ° C. for 3 hours, and then the slurry was dehydrated and washed to obtain TiO.₂/ SiO₂A titania-containing gel (c-1) having a weight ratio of 98/2 was obtained. Next, 0.18 kg of monoethanolamine and 1.00 kg of water were mixed, 0.16 kg of ammonium metavanadate was added thereto, and the mixture was heated and dissolved. After heating and kneading this solution and the above-mentioned titania-containing gel (c-1) 16.98 kg (oxide equivalent) with a kneader to a water content of 30 wt%, 0.9 kg of glass fiber and 0.27 kg of carboxymethyl cellulose are added and cooled. Kneaded to obtain a kneaded product. The kneaded product is extruded into a honeycomb shape with an outer diameter of 80 mm (outer diameter 80 mm × 80 mm square shape, the same applies hereinafter), a mesh size of 6.70 mm, a wall thickness of 1.20 mm, and a length of 500 mm using a vacuum extrusion molding machine. The molded product was dried at 110 ° C. for 12 hours and then calcined at 600 ° C. for 5 hours to obtain catalyst A.

Example 2 Metatitanic acid slurry [TiO₂Concentration 30wt%, manufactured by Ishihara Sangyo Co., Ltd.] 58.77kg, zircon sulfate (ZrO)₂Concentration 18.19 wt%, made of rare metal) 2.20 kg was added and mixed in 10 minutes, then 15 wt% aqueous ammonia was added to adjust the pH of the slurry to 9.0, and the pH was 8.5 to 9.5 at a temperature of 70 ° C. It was warmed and aged for 1 hour while adding 15 wt% aqueous ammonia so as to maintain the temperature. Next, this slurry was dehydrated and washed, dried at 110 ° C for 12 hours, then calcined at 520 ° C for 5 hours, and pulverized to obtain a binary composite oxide powder (d) having an average particle size of 0.8 μm. -1) was obtained. Reslurry 15.39 kg of this powder (d-1) into 35.91 kg of water, and add 35 wt% hydrogen peroxide solution to it.₂O₂/ TiO₂Titanium oxide containing zirconia in which a part of the surface portion of the powder (d-1) is peroxotitanium oxide is added and mixed for 10 minutes so that the molar ratio becomes 1, and aged at 40 ° C for 30 minutes. A particle dispersion slurry (d-2) was prepared. Next, the titanium oxide particle dispersion slurry (d-2) was added to the same peroxotitanic acid solution (b-1) prepared in Example 1 at a ratio of 1: 9 (oxide conversion ratio) while stirring 30. After addition and mixing for 1 minute, 15 wt% aqueous ammonia was added to adjust the pH of the slurry to 7.5, and the mixture was aged at a temperature of 50 ° C. for 3 hours. The slurry is then dehydrated and washed to TiO.₂/ ZrO₂A titania-containing gel (e-1) having a composition of weight ratio = 98/2 was obtained. Next, the catalyst B was prepared in the same manner as in Example 1 using the titania-containing gel (e-1). That is, 0.18 kg of monoethanolamine and 1.00 kg of water were mixed, 0.16 kg of ammonium metavanadate was added thereto, and the mixture was heated and dissolved. This solution and the above-mentioned titania-containing gel (e-1) 16.98 kg (oxide equivalent) are heated and kneaded with a kneader to a water content of 30 wt%, and then 0.90 kg of glass fiber and 0.27 kg of carboxymethyl cellulose are added and cooled. Kneaded to obtain a kneaded product. The kneaded product is extruded into a honeycomb shape with an outer diameter of 80 mm , an opening of 6.70 mm, a wall thickness of 1.20 mm, and a length of 500 mm using a vacuum extrusion molding machine, and then the molded product is dried at 110 ° C for 12 hours. , 600 ° C. for 5 hours to obtain catalyst B.

Example 3 Metatitanic acid slurry [TiO₂Concentration 30 wt%, manufactured by Ishihara Sangyo Co., Ltd.] 52.00 kg, silica sol [SiO₂Concentration 20 wt%, trade name "Cataloid S-20L" manufactured by Catalyst Kasei Kogyo Co., Ltd.] 2.00 kg was added and mixed in 10 minutes, and then 15 wt% aqueous ammonia was added to adjust the pH of the slurry to 9.0. After heating and aging for 1 hour while adding 15 wt% aqueous ammonia so as to maintain pH 8.5 to 9.5 at a temperature of 70 ° C, 2.25 kg of tungstic acid was further added to this slurry, and the mixture was added at the same temperature and pH for 3 hours. Warm aged. Next, this slurry is dehydrated and washed, dried at 110 ° C for 12 hours, calcined at 520 ° C for 5 hours, and pulverized to obtain a ternary composite oxide powder (f) having an average particle size of 0.8 μm. -1) was obtained. Reslurry 15.39 kg of this powder (f-1) into 35.91 kg of water, and add 35 wt% hydrogen peroxide solution to it.₂O₂/ TiO₂Adds and mixes for 10 minutes so that the molar ratio becomes 1, and aged at 40 ° C for 30 minutes to contain silica and tungsten oxide in which a part of the surface portion of the powder (f-1) is peroxotitanium oxidized. Titanium oxide particle dispersion slurry (f-2) was prepared. Next, the titanium oxide particle dispersion slurry (f-2) was added to the same peroxotitanic acid solution (b-1) prepared in Example 1 at a ratio of 1: 9 (oxide conversion ratio) while stirring 30. After addition and mixing for 1 minute, 15 wt% aqueous ammonia was added to adjust the pH of the slurry to 7.5, and the mixture was aged at a temperature of 50 ° C. for 3 hours. Then, by dehydrating and washing this slurry, TiO₂/ WO₃/ SiO₂A titania-containing gel (g-1) having a composition of weight ratio = 88/10/2 was obtained. Next, the catalyst C was prepared in the same manner as in Example 1 using the titania-containing gel (g-1).

Comparative Example 1 Metatitanic acid slurry [TiO₂Concentration 30 wt%, manufactured by Ishihara Sangyo Co., Ltd.] 58.80 kg, silica sol [SiO₂Concentration 20 wt%, trade name "Cataloid S-20L" manufactured by Catalyst Kasei Kogyo Co., Ltd.] 1.80 kg was added and mixed in 10 minutes, then 15 wt% aqueous ammonia was added to adjust the pH of the slurry to 9.0, and the temperature was adjusted. It was aged by heating for 1 hour while adding 15 wt% aqueous ammonia so as to maintain pH 8.5 to 9.5 at 70 ° C. Next, this slurry was dehydrated and washed, dried at 110 ° C for 12 hours, then calcined at 520 ° C for 5 hours, pulverized, and a binary system (TiO) having an average particle size of 0.8 μm.₂/ SiO₂Weight ratio = 98/2) Composite oxide powder (h) was obtained. A catalyst D was prepared in the same manner as in Example 1 using this binary composite oxide powder (h) made of titanium-silicon.

Comparative Example 2 Metatitanic acid slurry [TiO₂Concentration 30wt%, manufactured by Ishihara Sangyo Co., Ltd.] 58.80kg, zircon sulfate (ZrO)₂Concentration 18.19 wt%, made of rare metal) 1.98 kg was added and mixed in 10 minutes, then 15 wt% aqueous ammonia was added to adjust the pH of the slurry to 9.0, and the pH was adjusted to 8.5 to 9.5 at a temperature of 70 ° C. It was warmed and aged for 1 hour while adding 15 wt% aqueous ammonia to maintain it. Next, this slurry was dehydrated and washed, dried at 110 ° C for 12 hours, then calcined at 520 ° C for 5 hours, pulverized, and a binary system (TiO) having an average particle size of 0.8 μm.₂/ ZrO₂Weight ratio = 98/2) Composite oxide powder (i) was obtained. A catalyst E was prepared in the same manner as in Example 1 using this binary composite oxide powder (i) composed of titanium-zirconium.

Comparative Example 3 Metatitanic Acid Slurry [TiO₂Concentration 30 wt%, manufactured by Ishihara Sangyo Co., Ltd.] 52.80 kg, silica sol [SiO₂Concentration 20 wt%, trade name "Cataloid S-20L" manufactured by Catalyst Kasei Kogyo Co., Ltd.] 1.80 kg was added and mixed in 10 minutes, then 15 wt% aqueous ammonia was added to adjust the pH of the slurry to 9.0, and the temperature was adjusted. Warm and age for 1 hour while adding 15 wt% aqueous ammonia so as to maintain pH 8.5 to 9.5 at 70 ° C. Further, add 2.03 kg of tungstic acid to the slurry and heat and age for another 3 hours under the same conditions. did. Next, this slurry was dehydrated and washed, dried at 110 ° C for 12 hours, calcined at 520 ° C for 5 hours, pulverized, and ternary system (TiO) having an average particle size of 0.8 μm.₂/ WO₃/ SiO₂Weight ratio = 88/10/2) Composite oxide powder (j) was obtained. A catalyst F was prepared in the same manner as in Example 1 using the ternary composite oxide powder (j) composed of titanium-silicon-tungsten.

Comparative Example 4 15 wt% aqueous ammonia was added to the same peroxotitanic acid solution (b-1) prepared in Example 1 to adjust the pH to 7.5, and the pH was maintained at pH 7.0 to 8.0 at a temperature of 50 ° C. The mixture was heated and aged for 3 hours while adding 15 wt% aqueous ammonia. The slurry was then dehydrated and washed, dried at 110 ° C for 12 hours, then calcined at 520 ° C for 5 hours, pulverized and TiO with an average particle size of 1.2 μm.₂Powder (b-2) was obtained. Next, Comparative Example except that 15.28 kg of the same ternary composite oxide powder (f-1) as prepared in Example 3 and 1.70 kg of the powder (b-2) were mixed and used. Catalyst G was prepared in the same manner as in 3.

Example 4 A catalyst in the same manner as in Example 3 except that a powder (g-2) obtained by drying a titania-containing gel (g-1) prepared in Example 3 at 110 ° C. for 12 hours was used. H was prepared.

Comparative Example 5 A titania-containing gel (g-1) similar to that prepared in Example 3 was dried at 110 ° C for 12 hours, and then calcined at 520 ° C for 3 hours, and a powder (g-3) was used. Except for the above, catalyst I was prepared in the same manner as in Example 3.

Comparative Example 6 Metatitanic acid slurry [TiO₂Concentration 30 wt%, manufactured by Ishihara Sangyo Co., Ltd.] 52.00 kg, silica sol [SiO₂Concentration 20 wt%, trade name "Cataloid S-20L" manufactured by Catalyst Kasei Kogyo Co., Ltd.] 2.00 kg was added and mixed in 10 minutes, and then 15 wt% aqueous ammonia was added to adjust the pH of the slurry to 9.0. After heating and aging for 1 hour while adding 15 wt% aqueous ammonia so as to maintain pH 8.5 to 9.5 at a temperature of 70 ° C, 2.25 kg of tungstic acid was further added to this slurry, and the mixture was added at the same temperature and pH for 3 hours. Warm aged. The slurry is then dehydrated and washed to TiO.₂/ WO₃/ SiO₂A gel (f-3) having a composition of weight ratio = 88/10/2 was obtained. Next, 15 wt% aqueous ammonia was added to a peroxotitanic acid solution (b-1) similar to that prepared in Example 1 to prepare a slurry having a pH of 7.5, and the slurry was prepared at a temperature of 50 ° C. and had a pH of 7. After heating and aging for 1 hour while adding 15 wt% aqueous ammonia so as to maintain 0 to 8.0, this slurry is dehydrated and washed, and TiO₂A gel (b-3) was obtained. Next, a comparative example except that 15.28 kg (oxide equivalent) of the gel (b-3) and 1.70 kg (oxide equivalent) of the ternary composite oxide gel (f-3) were mixed and used. A kneaded product was obtained in the same manner as in 3, and an attempt was made to mold this into a honeycomb shape with an outer diameter of 80 mm , an opening of 6.70 mm, a wall thickness of 1.20 mm, and a length of 500 mm using a vacuum extrusion molding machine. The kneaded product could not be molded due to dehydration [the molded product catalyst (J) of Comparative Example 6 could not be obtained].

Comparative Example 7 15.28 kg of ternary composite oxide powder (f-1) similar to that prepared in Example 3 and TiO similar to that prepared in Comparative Example 6.₂The catalyst K was prepared in the same manner as in Comparative Example 3 except that 1.70 kg (oxide equivalent) of gel (b-3) was mixed and used.

Comparative Example 8 Metatitanic Acid Slurry [TiO₂Concentration 30 wt%, manufactured by Ishihara Sangyo Co., Ltd.] 15 wt% aqueous ammonia was added to 54.00 kg to adjust the pH of the slurry to 9.0, and 15 wt% to maintain pH 8.5 to 9.5 at a temperature of 70 ° C. After heating and aging for 1 hour while adding aqueous ammonia, 2.03 kg of tungstic acid was further added to this slurry, and the mixture was heated and aged at the same temperature and pH for 3 hours. Next, this slurry is dehydrated and washed, dried at 110 ° C for 12 hours, then calcined at 520 ° C for 5 hours, pulverized and pulverized to form a binary system (TiO) consisting of titanium-tungsten having an average particle size of 0.8 μm.₂/ WO₃Weight ratio = 90/10) Composite oxide powder (k) was obtained. The catalyst L was prepared in the same manner as in Example 1 except that 16.98 kg of this binary composite oxide powder (k) was used.

Example 5 In Example 3, the amount of 35 wt% hydrogen peroxide solution added to 15.39 kg of the ternary composite oxide powder (f-1) reslurried in 35.91 kg of water is H.₂O₂/ TiO₂The molar ratio was set to 0.5, and the amount of 35 wt% hydrogen peroxide solution added to the titanyl sulfate aqueous solution (same as the titanyl sulfate aqueous solution of Example 1) prepared in the same example was H.₂O₂/ TiO₂A titania-containing gel (g-4) was obtained in the same manner as in Example 3 except that the molar ratio was 0.5. Next, the catalyst M was prepared in the same manner as in Example 1 using the titania-containing gel (g-4).

Example 6 In Example 3, the amount of 35 wt% hydrogen peroxide solution added to 15.39 kg of the ternary composite oxide powder (f-1) reslurried in 35.91 kg of water is H.₂O₂/ TiO₂The molar ratio was set to 2.0, and the amount of 35 wt% hydrogen peroxide solution added to the titanyl sulfate aqueous solution prepared in the same example was H.₂O₂/ TiO₂A titania-containing gel (g-5) was obtained in the same manner as in Example 3 except that the molar ratio was set to 2.0. Next, the catalyst N was prepared in the same manner as in Example 1 using the titania-containing gel (g-5).

Example 7 Metatitanic acid slurry [TiO₂Concentration 30 wt%, manufactured by Ishihara Sangyo Co., Ltd.] 58.29 kg, silica sol [SiO₂Concentration 20 wt%, trade name "Cataloid S-20L" manufactured by Cataloid Chemical Industry Co., Ltd.] 2.57 kg was added and mixed in 10 minutes, and then 15 wt% aqueous ammonia was added to adjust the pH of the slurry to 9.0. Next, the slurry was warmed and aged for 1 hour while adding 15 wt% aqueous ammonia so as to maintain pH 8.5 to 9.5 at a temperature of 70 ° C., the slurry was dehydrated and washed, and dried at 110 ° C. for 12 hours. After that, it was calcined at 520 ° C. for 5 hours, and this was pulverized to obtain a binary composite oxide powder (l-1) having an average particle size of 0.8 μm. Reslurry 15.39 kg of this powder (l-1) into 35.91 kg of water, and add 35 wt% hydrogen peroxide solution to it.₂O₂/ TiO₂Titanium oxide containing silica obtained by peroxotitanium-oxidizing a part of the surface portion of the powder (l-1) after adding and mixing for 10 minutes so that the molar ratio becomes 1 and aging at 40 ° C for 30 minutes. A particle dispersion slurry (l-2) was prepared. Next, titanyl sulfate crystal [TiO₂Concentration 32 wt%, manufactured by TAYCA Corporation] A 35 wt% hydrogen peroxide solution is added to an aqueous solution of titanyl sulfate diluted by dissolving 16.02 kg in 64.14 kg of water.₂O₂/ TiO₂The mixture was added and mixed for 1 minute so that the molar ratio was 1, and a peroxotitanic acid solution (m-1) was obtained. Next, the titanium oxide particle dispersion slurry (l-2) was added and mixed with the peroxotitanic acid solution (m-1) at a ratio of 3: 7 (oxide conversion ratio) in 30 minutes with stirring, and then 15 wt%. Ammonia water is added to adjust the pH of the slurry to 7.5, the slurry is aged at a temperature of 50 ° C. for 3 hours, and then the slurry is dehydrated and washed to obtain TiO.₂/ SiO₂A titania-containing gel (n-1) having a composition of weight ratio = 98/2 was obtained. The catalyst O was prepared in the same manner as in Example 1 except that the titania-containing gel (n-1) was used.

Example 8 Metatitanic acid slurry [TiO₂Concentration 30 wt%, manufactured by Ishihara Sangyo Co., Ltd.] 57.00 kg, silica sol [SiO₂A concentration of 20 wt% and a trade name of "Cataloid S-20L" manufactured by Catalytic Chemical Industry Co., Ltd.] 4.50 kg were added and mixed in 10 minutes, and then 15 wt% aqueous ammonia was added to adjust the pH of the slurry to 9.0. Next, the slurry was warmed and aged for 1 hour while adding 15 wt% aqueous ammonia so as to maintain pH 8.5 to 9.5 at a temperature of 70 ° C., the slurry was dehydrated and washed, and dried at 110 ° C. for 12 hours. After that, it was calcined at 520 ° C. for 5 hours, and this was pulverized to obtain a binary composite oxide powder (o-1) having an average particle size of 0.8 μm. Reslurry 15.39 kg of this powder (o-1) into 35.91 kg of water, and add 35 wt% hydrogen peroxide solution to it.₂O₂/ TiO₂Titanium oxide containing silica obtained by peroxotitanium-oxidizing a part of the surface portion of the powder (o-1) after adding and mixing for 10 minutes so that the molar ratio becomes 1 and aging at 40 ° C for 30 minutes. A particle dispersion slurry (o-2) was prepared. Next, titanyl sulfate crystal [TiO₂Concentration 32 wt%, manufactured by TAYCA CORPORATION] 32.04 kg dissolved in 128.28 kg of water diluted with titanyl sulfate aqueous solution, 35 wt% hydrogen peroxide solution H₂O₂/ TiO₂A peroxotitanic acid solution (p-1) was obtained by adding and mixing in 1 minute so that the molar ratio was 1. Next, the titanium oxide particle dispersion slurry (o-2) was added and mixed with the peroxotitanic acid solution (p-1) at a ratio of 6: 4 (oxide conversion ratio) in 30 minutes with stirring, and then 15 wt. % Ammonia water is added to adjust the pH of the slurry to 7.5, and the slurry is aged at a temperature of 50 ° C. for 3 hours, and then the slurry is dehydrated and washed to obtain TiO.₂/ SiO₂A titania-containing gel (q-1) having a composition of weight ratio = 98/2 was obtained. The catalyst P was prepared in the same manner as in Example 1 except that the titania-containing gel (q-1) was used.

Example 9 Metatitanic acid slurry [TiO₂Concentration 30wt%, manufactured by Ishihara Sangyo Co., Ltd.] 57.33kg, zircon sulfate (ZrO)₂Concentration 18.19 wt%, made of rare metal) 2.20 kg was added and mixed in 10 minutes, and then silica sol [SiO]₂A concentration of 20 wt% and a trade name of "Cataloid S-20L" manufactured by Catalyst Kasei Kogyo Co., Ltd.] 2.00 kg was added and mixed for 10 minutes, and then 15 wt% aqueous ammonia was added to adjust the pH of the slurry to 9.0. Next, the slurry was warmed and aged for 1 hour while adding 15 wt% aqueous ammonia so as to maintain pH 8.5 to 9.5 at a temperature of 70 ° C., the slurry was dehydrated and washed, and dried at 110 ° C. for 12 hours. Then, it was calcined at 520 ° C. for 5 hours, and the obtained calcined product was pulverized to obtain a binary composite oxide powder (r-1) having an average particle size of 0.8 μm. Reslurry 15.39 kg of this powder (r-1) into 35.91 kg of water, and add 35 wt% hydrogen peroxide solution to it.₂O₂/ TiO₂Titanium oxide containing silica obtained by peroxotitanium-oxidizing a part of the surface portion of the powder (r-1) after adding and mixing at 40 ° C for 30 minutes so that the molar ratio becomes 1 = 1. A particle dispersion slurry (r-2) was prepared. Next, the titanium oxide particle dispersion slurry (r-2) was mixed with the same peroxotitanic acid solution (b-1) prepared in Example 1 at a ratio of 1: 9 (oxide conversion ratio) while stirring. After addition and mixing for 30 minutes, 15 wt% aqueous ammonia was added to adjust the pH of the slurry to 7.5, and the mixture was aged at a temperature of 50 ° C. for 3 hours. The slurry is then dehydrated and washed to TiO.₂/ ZrO₂/ SiO₂A titania-containing gel (s-1) having a composition of weight ratio = 96/2/2 was obtained. Next, the catalyst B was prepared in the same manner as in Example 1 using the titania-containing gel (s-1). That is, 0.18 kg of monoethanolamine and 1.00 kg of water were mixed, 0.16 kg of ammonium metavanadate was added thereto, and the mixture was heated and dissolved. After heating and kneading this solution and the above-mentioned titania-containing gel (s-1) 16.98 kg (oxide equivalent) with a kneader to a water content of 30 wt%, 0.90 kg of glass fiber and 0.27 kg of carboxymethyl cellulose are added and cooled. Kneaded to obtain a kneaded product. The kneaded product was extruded into a honeycomb shape having an outer diameter of 80 mm , an opening of 6.70 mm, a wall thickness of 1.20 mm, and a length of 500 mm using a vacuum extrusion molding machine, and then the molded product was dried at 110 ° C. for 12 hours. After that, the catalyst Q was obtained by firing at 600 ° C. for 5 hours.

Example 10 To 15.28 kg (oxide equivalent) of the titania-containing gel (s-1) obtained in Example 9, 0.18 kg of monoethanolamine, 1.00 kg of water, and 0.16 kg of ammonium metavanadate are mixed and heated. The dissolved solution was added, and 1.91 kg of ammonium paratungstate was further added. This was heated and kneaded with a kneader to a moisture content of 30 wt%, 0.90 kg of glass fiber and 0.27 kg of carboxymethyl cellulose were added thereto, and the mixture was cooled and kneaded to obtain a kneaded product. The kneaded product was extruded into a honeycomb shape having an outer diameter of 80 mm , an opening of 6.70 mm, a wall thickness of 1.20 mm, and a length of 500 mm using a vacuum extrusion molding machine, and then the molded product was dried at 110 ° C. for 12 hours. After that, the catalyst R was obtained by firing at 600 ° C. for 5 hours.

The composition of the carrier used as the catalyst of each Example and Comparative Example is shown in Table 1, and the catalyst composition when catalyzed is shown in Table 2.

Example 11 Evaluation test of catalyst An activity test and an abrasion test were carried out using the catalysts (A) to (R) prepared in Examples 1 to 10 and Comparative Examples 1 to 8.

&lt;Nitrogen oxide removal ability test&gt; A 300 mm length cut out from each honeycomb catalyst into 3 × 3 pieces was filled in a flow reactor, and the denitration rate was measured under the following conditions. The denitration rate was determined by measuring the concentration of nitrogen oxide NOx in the gas before and after contact with the catalyst with a Chemilmi-type nitrogen oxide analyzer and using the following formula.<maths num="1"><img file="JP2008024565A_D0001.tif" /></maths> Test conditions Catalyst shape: 3 × 3, length: 300 mm, reaction temperature: 380 ° C, SV = 10,000hr^-1 Gas composition: NOx = 180ppm, NH₃= 180, SO₂= 500ppm, O₂= 2%, H₂O = 10%, N₂= Balance

&lt;SOx Oxidation Test&gt; A 300 mm length cut out from each honeycomb catalyst into 3 x 3 pieces is filled in a flow reactor, and SO is performed under the following conditions.₃The conversion rate was measured. SO₃Conversion rate is SO in gas before and after catalyst contact₂Infrared SO concentration₂It was measured with a gas concentration meter and calculated by the following formula.<maths num="2"><img file="JP2008024565A_D0002.tif" /></maths> Test conditions Catalyst shape: 3 x 3 stitches, length: 300 mm, reaction temperature: 380 ° C, SV = 10,000hr^-1 Gas composition: O₂= 2%, SO₂= 500ppm, N₂= Balance

&lt;Abrasion test&gt; From each honeycomb catalyst, a test sample cut into 6 × 6 pieces with a length of 100 mm is filled in a flow reactor, and a gas containing dust is flowed under the following conditions to determine the abrasion rate from the reduced weight of the catalyst. It was measured.<maths num="3"><img file="JP2008024565A_D0003.tif" /></maths> Test conditions Catalyst shape: 6 × 6, length: 100 mm Gas flow rate: 40 m / s (catalyst cross section), gas temperature: room temperature Gas flow time: 30 min Dust concentration: 70 g / Nm³ Dust: Quartz Sand No. 3 manufactured by Mikawa Quartz Sand Co., Ltd.

&lt;Results of catalyst evaluation test&gt; Table 2 shows the results of the catalyst evaluation test. Comparing Example 1 (Catalyst A) and Comparative Example 1 (Catalyst D), Example 2 (Catalyst B) and Comparative Example 2 (Catalyst E), and Example 3 (Catalyst C) and Comparative Example 3 (Catalyst F). , The catalyst of the present invention has a high denitration rate and SO.₂It can be seen that the oxidation rate is low. Regarding the wear rate, the catalyst of the present invention shows a slightly higher value than the catalyst of the comparative example, but it has sufficient strength for practical use as an industrial catalyst and there is no problem. In addition, Example 7 (catalyst O) in which a larger amount of peroxotitanic acid from the peroxotitanic acid solution was used had a high denitration rate and SO.₂The oxidation rate is also low. In Example 8 (catalyst P), in which the amount of peroxotitanic acid from the peroxotitanic acid solution was higher, the denitration rate was further improved, but SO.₂The oxidation rate has increased.

<tables num="1"><img file="JP2008024565A_D0004.tif" /></tables>

<tables num="2"><img file="JP2008024565A_D0005.tif" /></tables>

<figref num="1">It is a figure which shows the manufacturing process of the modified titanium oxide particle in Example 1. FIG.</figref><figref num="2">It is a figure which shows the process of manufacturing the catalyst from the modified titanium oxide particle in Example 1. FIG.</figref>