JP2000000464A - Support for catalyst, its production and denitration catalyst and denitration method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a support used for a denitration catalyst having high durability against a poisonous material such as As contained in a waste gas and low in SO2 oxidation ratio, the producing method, the denitration catalyst and the denitration method. SOLUTION: Denitration active metals of at least one kind among V2O5, WO3 and MoO3 are supported on the support for catalyst composed of a multiple oxide, which is obtained by mixing a Ti salt aq. solution with at least one kind of each alkoxide of Si, P and B, neutralizing, aging and after that, washing, drying and firing and has composition ratio, by weight, between TiO2 and the total of SiO2, P2O5 and B2O3 of 50:50-99:1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst carrier having a high solid acid content useful as various catalyst carriers, particularly to a flue gas denitration apparatus installed in a power plant, various chemical factories or sintering furnaces. Denitration catalyst carrier, especially a denitration catalyst carrier suitable for a denitration apparatus for coal-fired boiler combustion exhaust gas containing a large amount of catalyst poisons in the exhaust gas, a method for producing the same, a denitration catalyst supporting an active metal on the carrier, and The present invention relates to a method for denitrifying combustion exhaust gas using the same.

[0002]

2. Description of the Related Art Nitrogen oxides (NOx) in exhaust gas discharged from various combustion processes generate acid rain which causes soil pollution, deforestation, etc., and its reduction is now worldwide. Important issues. The most successful denitration method for removing NOx at present is a selective catalytic reduction method using ammonia (NH ₃ ). In this method, NH ₃ is added to the exhaust gas as a reducing agent and optionally used as an oxidizing agent. By adding air (addition is unnecessary if the required amount of oxygen is present in the combustion exhaust gas), NOx is selectively catalytically reduced on the catalyst,
It produces harmless nitrogen (N ₂ ) and water (H ₂ O). The reaction formula of the selective catalytic reduction of ammonia and oxygen of NO is shown below. 4NO + 4NH ₃ + O ₂ → 4N ₂ + 6H ₂ O NO ₂ also generates nitrogen and water by the catalyst similarly to NO.

[0003] In order to proceed the reaction, the catalyst was supported active metal such as V ₂ O _5, WO ₃ or MoO ₃ catalyst support of TiO ₂ system has been widely applied, the solid acid points on the TiO ₂ And the active site of the active metal supported thereon acts on the denitration reaction. However, when coal or heavy oil is used as a fuel, if a TiO ₂ -based catalyst is used for flue gas denitration, arsenic (As), calcium (C) contained in exhaust gas
Components poisoned by the catalyst such as a) accumulate on the catalyst and cover the active sites, and the performance of the catalyst decreases over time. In particular, As in the exhaust gas becomes As ₂ O ₃ having a high vapor pressure, which is oxidized to As ₂ O ₅ having a low vapor pressure on the catalyst and covers the catalytically active sites. As ₂ O ₃ + O ₂ → As ₂ O ₅ For this reason, especially when coal containing a large amount of As, which has a large influence on the deterioration of the catalyst, is used as a fuel, the durability of the catalyst against As becomes an important issue. .

When coal or heavy oil is used as fuel, sulfur oxides (SOx: especially SO ₂ ) are present in the exhaust gas and are oxidized to SO ₃ on the catalyst. SO ₂ + 1 / 2O ₂ → SO _{3 The} generated SO ₃ reacts with unreacted NH ₃ and moisture downstream of the denitration apparatus to generate acidic ammonium sulfate (NH ₄ HSO ₄ ), and treats various exhaust gases such as a heat exchanger. Since it causes blockage and corrosion in the apparatus, the low SO ₂ oxidation rate as well as the denitration activity are also important conditions for the denitration catalyst.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide As
Has strong durability against catalyst poisoning substances such as
An object of the present invention is to provide a carrier for a denitration catalyst having a low O ₂ oxidation rate, a method for producing the same, a denitration catalyst having an active metal supported on the carrier, and a method for denitration of combustion exhaust gas using the catalyst.

[0006]

SUMMARY OF THE INVENTION The inventors of the present invention have found that a catalyst having a large amount of solid acid (that is, an acid point generated by bias of electric charge on a solid surface) can suppress deterioration due to As by a study to date. Was found. On the other hand, it is known that when an oxide is complexed, some elements show a higher solid acid amount than a single oxide. Then, they have found that the coprecipitation method is suitable as a method for preparing a homogeneous composite oxide. The present inventors have conducted intensive studies based on the above findings to solve the above-mentioned problems, and as a result, after making a solution of Ti sulfate or acetate, at least one of the alkoxides of Si, P and B has been prepared. By mixing and neutralizing the mixture by adding an alkali thereto, aging and co-precipitating the composite oxide, the solid acid amount is larger than before, and it has been found that a carrier for a denitration catalyst having excellent performance can be obtained. The present invention has been completed.

That is, a first aspect of the present invention is a step of mixing a Ti sulfate and / or acetate solution with at least one of alkoxides of Si, P and B to obtain a mixed solution.
A step of obtaining a precipitate by neutralizing and aging the mixture with an alkaline solution, and a step of washing, drying and calcining the precipitate to obtain a composite oxide, wherein the composite oxide has a weight of [TiO ₂ ] : [Total weight of SiO ₂ , P ₂ O ₅ and B ₂ O ₃ ] = 50: 50 to 99: 1. A second aspect of the present invention provides a catalyst carrier obtained by the first production method of the present invention. Third of the present invention
The present invention provides a denitration catalyst comprising the catalyst carrier according to the second aspect of the present invention and a denitration active metal supported thereon. According to a fourth aspect of the present invention, there is provided a denitration method comprising catalytically reducing combustion exhaust gas containing NOx and SOx and / or arsenic oxide with ammonia in the presence of the denitration catalyst according to the third aspect of the present invention. I do.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The catalyst carrier of the present invention comprises a step of mixing a Ti sulfate and / or acetate solution with at least one of alkoxides of Si, P and B to obtain a mixed solution. A mixed oxide produced and produced by a process comprising the steps of neutralizing and aging the mixed solution with an alkaline solution to obtain a precipitate, washing, drying and calcining the precipitate to obtain a composite oxide Is the weight of TiO ₂ : SiO ₂ , P ₂ O ₅ and B
The composition has a composition ratio of the total weight of ₂ O ₃ of 50:50 to 99: 1. Hereinafter, the elements Si, P and B are represented by M, their alkoxides are called M alkoxides, and their oxides are called M oxides. The total amount of the M oxide is the amount of the M oxide derived from at least one of the mixed alkoxides of Si, P, and B.
The amount of the oxide of the element not included is defined as 0, and is formally expressed as the total weight of SiO ₂ , P ₂ O ₅ and B ₂ O ₃ .

Salts such as Ti sulfate and acetate used as a raw material in the present invention are preferably TiOS
O ₄ , Ti (SO ₄ ) ₂ , Ti ₂ (SO ₄ ) ₃ , Ti (OCO
CH ₃ ) ₄ , TiO (OCOCH ₃ ) ₂ , Ti ₂ (OCOC
H ₃ ) _{6 and the} like. By using inexpensive Ti sulfates and acetates as Ti sources, it is possible to significantly reduce the cost of the catalyst carrier. Ti sulfate and / or acetate (hereinafter abbreviated as Ti salt) is dissolved in water to form a solution. In order to smoothly proceed the neutralization treatment in the subsequent step to obtain a homogeneous carrier, the amount of water is preferably at least 10 times the molar ratio of the moles of the Ti salt, more preferably at least 40 times the molar ratio. Particularly preferred. The amount of water is not particularly limited. However, if the amount of water is increased more than necessary, the effect is not particularly increased, and conversely, the apparatus is increased in size and leads to an increase in cost. The ratio is sufficient.

In the present invention, Si used as a raw material,
Each of the alkoxides of P and B is represented by the general formula: MOm (OR ₁ )
n (R ₁ is an alkyl group having 1 to 20, preferably 1 to 5 carbon atoms, n is the number of M-OR bonds, m is the number of M = O-bonded oxygen, and 2m + n is the oxidation of M It is a number.) Preferred examples of the M alkoxide include Si
(OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , P (OCH ₃ ) ₃ ,
PO (OCH ₃ ) ₃ , B (OCH ₃ ) ₃ , B (OC ₂ H ₅ ) ₃
And the like. These alkoxides may be solids soluble in alcohol or water, but are preferably liquid at around room temperature. When soluble in alcohol, an alcohol solution of M alkoxide may be mixed with a Ti salt solution.

The carrier of the present invention is produced by the following process. First, the Ti salt solution obtained as described above and one or more M alkoxides are mixed at a predetermined ratio while stirring, and further stirred and mixed for 5 minutes or more, preferably for 1 hour or more. Obtain a mixture. For mixing both, M alkoxide may be added to the Ti salt solution,
A Ti salt solution may be added to the alkoxide or its solution, but preferably, the M alkoxide is added to the Ti sulfate solution. Mixing is carried out at room temperature, but there is no particular problem with heating and addition of a solvent such as alcohol in order to increase the dissolution rate of alkoxides having a property of being hardly soluble in water.

The obtained mixture is neutralized with an alkaline solution to obtain a precipitate. By the neutralization, the Ti compound and the M compound are co-precipitated without segregation so that a preferable composite oxide is obtained by firing the precipitate. The type of the alkaline solution is not particularly limited in the neutralization treatment, but an aqueous ammonia solution (NH ₄ OH) or urea (CO (NH ₂ ) ₂ ) as an ammonia generation source is generally used. Also,
Although the concentration of the alkaline solution is not particularly limited, the neutralization treatment is difficult at a high concentration, and the neutralization treatment takes a long time at a low concentration, which is not preferable in terms of work. Therefore, 7 to 10 vol. Aqueous solutions are particularly desirable.
The order of adding the mixed solution and the alkaline solution is not limited.

After the mixture is neutralized to obtain a precipitate, 5
The mixture is aged by stirring for at least 2 minutes, preferably at least 2 hours. Aging further increases the bond and specific surface area of -Ti-OM-. Then, since the number of oxygen atoms having excess or deficiency of electrons increases, the amount of solid acid also increases.

As described above, by using a highly reactive alkoxide as a raw material of M and compounding it with Ti, Ti and M are dispersed and coordinated to form a homogeneous composite having a large amount of solid acid and a large amount of solid acid. An oxide can be obtained. Ti
M is an oxide suitable for a denitration catalyst because M is an element that is hardly poisoned by SO ₂ in exhaust gas.

The precipitate obtained by mixing, neutralizing and aging in the preferred range described above is filtered, washed with water, dried and calcined to form a composite oxide of TiO ₂ and M oxide. A carrier can be obtained. This composite oxide has an amorphous and / or at least partly anatase TiO ₂ type crystal structure. The firing temperature varies depending on the composition ratio of the composite oxide and the like, but is in the range of 300 ° C to 1,000 ° C, preferably 400 ° C to 550 ° C. The firing time varies depending on the composition ratio of the composite oxide, the firing temperature, and the like, but is in the range of 5 minutes to 24 hours, preferably 4 to 5 hours. If the firing temperature and time are less than the above ranges, the firing will be insufficient, and if it exceeds the above range, the specific surface area will decrease and the denitration activity will decrease, which is not preferable.

In the present invention, the ratio between TiO ₂ and the total amount of M oxide in the carrier is 50:50 to 99:99 by weight.
1 range. If the ratio of M oxide is less than this range, there is no effect of compounding, and if it exceeds this range, T
i and M are adjacent via oxygen (-Ti-OM-)
The effect of bonding to form an acid point, which is an acid point due to the bias of charge on the solid surface, is not promoted, and TiO ₂
, A catalyst having satisfactory denitration performance cannot be obtained. The preferred range of each oxide is TiO ₂ : S
TiO ₂ = 80: 20 to 99: 1, TiO ₂ : P ₂ O ₅ = 5
0: 50-99: 1, TiO ₂ : B ₂ O ₃ = 50: 50-
99: 1.

V ₂ O ₅ and W are added to the carrier thus obtained.
By carrying at least one or more denitration active metals of O ₃ and MoO ₃ , NOx-containing gases such as NO and NO ₂ are efficiently denitrated by ammonia in the presence of oxygen, and a catalyst such as As in exhaust gas It is possible to obtain a denitration catalyst having strong durability against poisoning substances and low SO ₂ oxidation rate. These catalysts can be used in the form of a powder, granules, pellets, honeycomb, or the like.
In addition, a suitable carrier can be formed into a suitable shape as described above, and the active metal oxide can be supported on the formed carrier to obtain a denitration catalyst. The amount of active metal carried is determined by the content of active metal in the catalyst (active metal / (active metal + support)
× 100) is 0.1 to 30% by weight. In particular,
Preferred ranges are 0.2 to 5% by weight when the active metal is V, 0.1 to 20% by weight when the active metal is Mo, and 5 to 20% by weight when the active metal is W. There is no particular limitation on the method of supporting these active metals, and the active metal can be produced by a conventional method. The denitration catalyst thus obtained can be used for combustion exhaust gas such as boiler exhaust gas. In particular, the denitration catalyst of the present invention is used for combustion exhaust gas having a concentration of a catalyst poisoning substance such as As in exhaust gas of 1 ppm or less, preferably 100 ppb or less, for example, in an operation time of about 10,000 hours or more, although it depends on the usage time. it can. If the usage time is shorter than this, it can be used for combustion exhaust gas of about 100 ppm. Further, the SOx in the combustion exhaust gas, specifically, the SO ₂ concentration is 5,
It can be used for combustion exhaust gas of 000 ppm or less, preferably 1,000 ppm or less.

In general, a solid acid catalyst is used for reactions such as hydrocarbon cracking, hydrogen transfer, disproportionation, hydration, polymerization, isomerization of a skeleton and a double bond. Since the solid acid content itself is large, it also has a function as a solid acid catalyst, and is effective as a carrier for these reaction catalysts. In particular, since it has excellent heat resistance as compared with a solid acid catalyst synthesized in a metastable state such as zeolite, it is suitable for such a bifunctional catalyst. As an example to which such a bifunctional catalyst is applied, there is a catalytic oxidation reaction requiring oxidizing ability and acidity.

[0019]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 Preparation of Carrier and Amount of Solid Acid (Preparation of Carrier 1) 320.2 g of TiOSO ₄ and 1,4
After mixing 41.8 g of water at room temperature, 138.6 g of Si (OC ₂ H ₅ ) ₄ is mixed. Then 9 vo 1% NH ₄
OH water was slowly added dropwise to adjust the pH of the mixture to 7 to form a precipitate, and the mixture was further aged by stirring for 2 hours.
The precipitate obtained after aging was filtered, washed sufficiently with water, dried, and calcined (at 500 ° C. for 5 hours) to prepare Carrier 1. Tables 1 to 3 show the types of raw materials, the amounts used and the composition of the carrier 1 together with examples of the carriers 2 to 18 described below.

(Preparation of Carriers 2 to 18) The types and amounts of sulfates as Ti sources and alkoxides as M sources are shown in Table 1.
Carriers 2 to 18 were prepared under the same conditions as in Carrier 1 except that they were changed as shown in FIGS. Table 1 shows the composition of the obtained carrier.
3 are shown.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

(Preparation of Carriers 19 to 27) The types and amounts of acetic acid salts as the Ti source and alkoxides as the M source are shown in Tables 4 to 6 in the same manner as in the above-mentioned carrier 1, and
~ 27 were prepared. The compositions of the obtained carriers are shown in Tables 4 to 6.

[0026]

[Table 4]

[0027]

[Table 5]

[0028]

[Table 6]

[0029] 20 wt% TiC1 ₄ aqueous hydrochloric acid (Comparative Preparation of carrier 1) 1,899.4g and 20 wt% of SiO ₂
Was mixed with 319.8 g of silica sol (Si (OH) ₄ ) containing, and neutralized by adding 9 vol 1% aqueous ammonia to adjust the pH to 7. The resulting precipitate was filtered, washed, dried and calcined (at 500 ° C. for 5 hours) to obtain a carrier as Comparative Carrier 1.

(Preparation of Comparative Carrier 2) 27.6 g of phosphoric acid (H ₃ PO ₄ ) was added to 1102.8 g of a 20 wt% aqueous solution of metatitanic acid (TiO (OH) ₂ ), stirred, and evaporated. The carrier obtained by drying and calcining (500 ° C. for 5 hours) was used as Comparative Carrier 2.

(Preparation of Comparative Carrier 3) 1,213.0 g of a 20 wt% aqueous solution of metatitanic acid (TiO (OH) ₂ ) and 3.6 g of boric acid (H ₃ BO ₃ ) were added and stirred.
The carrier obtained by evaporating to dryness and calcining (500 ° C. for 5 hours) was used as Comparative Carrier 3. Table 7 summarizes the types of raw materials, the amounts used, and the compositions of the obtained carriers for Comparative Carriers 1 to 3.

[0032]

[Table 7]

(Measurement of Solid Acid Content of Carrier) The solid acid contents of the carriers 1 to 27 of the present invention prepared in Example 1 and the comparative carriers 1 to 3 were measured by a pyridine temperature programmed adsorption / desorption method. The outline of the measuring method is as follows. 12.5mg each carrier powder
After weighing each sample and treating at 450 ° C. for 30 minutes in a helium (He) stream of 40 ml / min, the sample was kept at 150 ° C., 0.2 μl of pyridine was injected in a pulsed manner, and pyridine was adsorbed until saturation. Was. Then, the carrier powder is cooled to 30 ° C.
The amount of pyridine to be desorbed was measured by a FID (hydrogen flame ionization) detector, and the amount of solid acid was determined from this value (moles of pyridine to be desorbed per 1 g of catalyst). The results are shown in Tables 8 to 14. As a result, when the solid acid content of the carrier of the present invention and the comparative carrier having the same composition were compared, it was found that the solid acid content of the carrier of the present invention was all larger.

[0034]

[Table 8]

[0035]

[Table 9]

[0036]

[Table 10]

[0037]

[Table 11]

[0038]

[Table 12]

[0039]

[Table 13]

[0040]

[Table 14]

Example 2: Manufacture of honeycomb catalyst and denitration activity (Manufacture of honeycomb catalysts 1 to 27) 7.7 g of ammonium metavanadate (NH ₄ VO ₃ ) and ammonium paratungstate ((NH ₄ ) ₁₀ W ₁₂ ) O ₄₁ · 5H ₂ O) 18.6
g of the carrier 1 to 27 prepared above was dissolved in 110 ml of a 10 wt% aqueous solution of methylamine, and the powder of each of the carriers 1 to 27 was 178.0.
g, impregnated, dried and fired (at 500 ° C. for 5 hours), and 3 wt% of V ₂ O ₅ and 8 wt% of WO ₃ were added to the carrier.
% Supported catalyst powder was obtained. 800 g of this catalyst powder
Of water, sufficiently stirred and crushed with a ball mill, and
A slurry for wash coating of a wt% catalyst powder was prepared. Next, 91.4 wt% TiO ₂ -0.6 wt% V ₂ O
_{5 -8wt%} honeycomb substrate with the composition of WO ₃ sufficiently immersed (shape of size 16 × 16 × 60mm, the lattice spacing 7.5 mm, wall thickness 1.0 mm, see Fig. 1) to the slurry for the washcoat After removing excess slurry,
Dried at 00 ° C. Court amount of substrate 1m ² per 10
0 g, and this coated material was used as honeycomb catalysts 1 to 27.

(Production of Comparative Honeycomb Catalysts 1 to 3) Comparative honeycombs coated with catalyst powders supporting V ₂ O ₅ and WO ₃ using the above-mentioned comparative supports 1 to 3 in the same manner as in the production of the honeycomb catalyst 1 Catalysts 1 to 3 were produced.

(Test for Evaluating Denitration Activity) The honeycomb catalysts 1 to 27 prepared in Example 2 were forcibly deteriorated by exposure to a gas containing a high concentration of As, and the denitration activity before and after the exposure was evaluated. The exposure treatment is performed by using the honeycomb catalyst 1 in the forced deterioration device.
While heating the As ₂ O ₃ gas side to 200 ° C. and the honeycomb catalyst side to 350 ° C., a gas having a composition shown in Table 15 was flowed, and the gas containing As ₂ O ₃ was brought into contact with the honeycomb catalyst surface. After 2 hours, the reaction was carried out by removing the catalyst. Next, using the honeycomb catalyst before and after the forced degradation treatment of As, a denitration activity test was performed under the conditions shown in Table 16,
The denitration performance was evaluated. The denitration rate was calculated by the following equation (1). Denitration rate (%) = [(inlet NOx concentration-outlet NOx concentration) / inlet NOx concentration] × 100 (1) The evaluation results are shown in Tables 17 to 23. Tables 11 to 14 show that the catalyst using the carrier of the present invention has excellent resistance to poisoning with respect to As because the decrease in the denitration rate before and after the forced degradation treatment of As is smaller than that of the catalyst using the comparative carrier. It turns out that it has.

[0044]

[Table 15]

[0045]

[Table 16]

[0046]

[Table 17]

[0047]

[Table 18]

[0048]

[Table 19]

[0049]

[Table 20]

[0050]

[Table 21]

[0051]

[Table 22]

[0052]

[Table 23]

(Evaluation test of denitration activity and SO ₂ oxidation rate)
Exhaust gas often contains SO ₂ , which is oxidized to SO ₃ on a catalyst. And N that has not reacted with SO ₃
Since NH ₄ HSO ₄ generated by the reaction between H ₃ and water is disadvantageously deposited on various exhaust gas treatment apparatuses, it is also important that the denitration catalyst has a low SO ₂ oxidation rate as well as a denitration activity. Therefore, using the honeycomb catalysts 1, 3, and 5 prepared in Example 2 and the comparative honeycomb catalysts 1 to 3, Table 24 was used.
The SO ₂ oxidation rate and the denitration rate were evaluated under the conditions shown below. The denitration rate was calculated using the above equation (1), and the SO ₂ oxidation rate was calculated by the following equation (2). SO ₂ oxidation rate (%) = (concentration of SO _{3 at} outlet / concentration of SO _{2 at} inlet) × 100 (2) Table 25 shows the test results. As a result, it was confirmed that the SO ₂ oxidation rate of the honeycomb catalyst of the present invention was almost halved as compared with the comparative honeycomb catalyst, and was sufficiently low.

[0054]

[Table 24]

[0055]

[Table 25]

[0056]

The catalyst carrier of the present invention has a large amount of solid acid,
Active metal oxide denitration catalyst was supported on this, it is possible for a long time maintaining a high denitration activity even in exhaust gas containing As, and SO ₂ oxidation performance is low, as compared with the conventional Very good. The catalyst carrier of the present invention is suitable for a reaction requiring a catalyst having a large amount of solid acid and a high acid point.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a part of a catalyst carrier powder of the present invention formed into a honeycomb mold.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kozo Iida 4--22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Inside the Hiroshima Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Shigeru Nojima 4-chome Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture No. 6-22 Mitsubishi Heavy Industries, Ltd. Hiroshima Research Laboratory (72) Inventor Rie Nakano 4-62 Kanon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries, Ltd. Hiroshima Research Laboratory F-term (reference) 4D048 AA06 AB02 AC04 BA04X BA04Y BA06X BA06Y BA23Y BA26Y BA27Y BA42X BA42Y BA44X BA44Y BB02 BC03 BC05 4G069 AA01 AA03 AA08 AA09 BA02A BA02B BA04A BA04B BA45C BB04A BB04B BB06A BB06B BB10C BC50C BC54B BC59B BC60B BD03A BD03B BD03C BD05A BD05B BD05C BD07A BD07B BD07C BE06C BE08C CA08 CA13 DA06 EA01Y EA18 ED07 FB05 FB08 FB15 FB27 FB30 FB31 FC02

Claims (4)

[Claims] 1. A method according to claim 1, wherein said solution comprises Ti sulfate and / or acetate.
mixing at least one of the alkoxides of i, P and B to obtain a mixture, neutralizing and aging the mixture with an alkali solution to obtain a precipitate, washing and drying the precipitate And firing to obtain a composite oxide,
The composite oxide has a composition of [weight of TiO ₂ ]: [total weight of SiO ₂ , P ₂ O ₅ and B ₂ O ₃ ] = 50: 50 to 99: 1. Production method. 2. A catalyst carrier obtained by the method according to claim 1. 3. A denitration catalyst comprising the catalyst carrier according to claim 2 carrying a denitration active metal. 4. The method according to claim 3, wherein
A denitration method comprising catalytically reducing combustion exhaust gas containing Ox, SOx and / or arsenic oxide with ammonia.