High-temperature-resistant SCR denitration catalyst as well as preparation method and application thereof

Abstract

The invention provides a high-temperature-resistant SCR denitration catalyst and a preparation method and application thereof.The denitration catalyst comprises active components and a carrier, the active components comprise vanadium pentoxide and tungsten trioxide, the carrier comprises titanium dioxide and silicon dioxide, the mass fraction of the active components in the denitration catalyst is 5.0-7.0 wt%, the mass ratio of the vanadium pentoxide to the tungsten trioxide is 1: (3.5-7), and the mass fraction of the carrier in the denitration catalyst is 1: (3.5-7). The molar ratio of titanium dioxide to silicon dioxide is (4-6): 1. The composition of the denitration catalyst is improved, a composite carrier of titanium dioxide and silicon dioxide is selected, the ratio of the titanium dioxide and the silicon dioxide is controlled, the thermal stability of the carrier is improved, and the situation that the activity is affected due to crystalline phase transformation during high-temperature impact is avoided; the catalyst is high in catalytic activity and wide in applicable temperature range; the catalyst is simple in composition and preparation process, stable in structure, free of additional heat compensation, efficient and energy-saving.

Description

Technical Field

[0001] The invention belongs to the technical field of flue gas catalytic denitration, and relates to a high temperature resistant SCR denitration catalyst and a preparation method and application thereof. Background Art

[0002] Pellet production is one of the important links in the steel industry and occupies an important position in the metallurgical industry. Compared with sintered ore, pellets have uniform particle size, high iron content and good reducibility. The use of pellets can increase steel production. At present, pellet production mainly adopts the chain grate-rotary kiln process, which has the characteristics of large production capacity, high heat utilization rate and low total energy consumption. It is suitable for my country's energy structure and is especially suitable for using pulverized coal as the main heat source. The pellets produced have uniform quality and high strength, and account for a large proportion of the national pellet production.

[0003] In the pellet production process, especially in the pellet roasting process, NO x Emissions are large, and most of them are thermal NO generated under high temperature conditions. x With the increasing requirements for environmental protection, how to effectively control NO x Emissions have become an urgent problem to be solved in the pelletizing industry. Traditional terminal denitrification technology has been unable to meet increasingly stringent environmental protection requirements due to its high energy consumption and large carbon emissions. Therefore, the development of embedded denitrification technology that fits the characteristics of the pelletizing process has important practical significance.

[0004] According to the structural division of the drying section and preheating section in the chain grate, the flue gas temperature between the second preheating section and the second drying section is basically consistent with the temperature range required for SCR denitrification. Therefore, an SCR denitrification reactor can be set between the two to achieve embedded denitrification. Compared with the traditional post-type low-temperature SCR denitrification technology, embedded denitrification can make full use of waste heat without the need for additional heat supplement. It has unique advantages in reducing pollution and carbon emissions. However, due to the special working conditions of the chain grate-rotary kiln, the second preheating section and the second drying section in the chain grate will be affected by the high temperature shock of the front area, resulting in excessive local temperature, which makes the denitrification catalyst face adverse factors such as phase change and sintering, thus affecting the denitrification effect.

[0005] CN 110721568A discloses a pellet roasting flue gas denitration and desulfurization device and method based on a chain grate-rotary kiln, the device includes a reaction system and a flue gas treatment system, the reaction system includes a chain grate and a rotary kiln, the flue gas treatment system includes an SNCR unit, an SCR unit, an ozone oxidation unit and a sulfur-nitrate absorption unit, the SCR unit is located between the outlet of the second preheating section and the inlet of the second drying section, and the catalyst used for the SCR treatment includes a vanadium-tungsten-titanium catalyst or a vanadium-molybdenum-titanium catalyst. The denitration treatment in the device adopts embedded denitration, but the temperature fluctuations existing during the operation of the chain grate and the possible influence on the activity of the denitration catalyst are not mentioned, and the service life of the catalyst cannot be guaranteed.

[0006] CN 102755898A discloses an SCR denitration catalyst suitable for high dust-containing flue gas conditions and a preparation method thereof, the method comprising: preparation of ammonium metavanadate solution; preparation of metal salt solution; primary mixing; primary extrusion drying and calcination; secondary mixing; secondary extrusion drying and calcination; in the method, surfactants, sizing agents and lubricants are added when preparing the vanadium-tungsten-titanium denitration catalyst, secondary microstructures and reasonable pore size distribution are formed through secondary drying and calcination, and an SCR denitration catalyst suitable for high dust-containing flue gas conditions is prepared. The patent improves the microstructure of the catalyst by using auxiliary reagents and secondary drying and calcination to make it suitable for high dust-containing conditions, but does not involve the influence of excessively high flue gas temperatures on the catalyst, nor does it make improvements in this regard.

[0007] In summary, the composition of the SCR denitrification catalyst and the selection of its preparation process need to be improved according to its application environment, so that it can still have high activity under high temperature conditions, a wide operating temperature range and high denitrification efficiency. Summary of the invention

[0008] In view of the problems existing in the prior art, the object of the present invention is to provide a high temperature resistant SCR denitration catalyst and its preparation method and use. The denitration catalyst is selected by titanium silicon oxide composite carrier, combined with vanadium tungsten oxide active components and the selection of their respective proportions, so that the denitration catalyst has high thermal stability and high temperature denitration activity, a wide applicable temperature range, and can maintain good NO for a long time under high temperature conditions. x Removal rate, can be widely used in high-efficiency and energy-saving denitrification process.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a high temperature resistant SCR denitration catalyst, the denitration catalyst comprising an active component and a carrier, the active component comprising vanadium pentoxide and tungsten trioxide, the carrier comprising titanium dioxide and silicon dioxide, the mass fraction of the active component in the denitration catalyst is 5.0 to 7.0 wt%, for example, 5.0 wt%, 5.2 wt%, 5.4 wt%, 5.6 wt%, 5.8 wt%, 6.0 wt%, 6.2 wt%, 6.4 wt%, 6.6 wt%, 6.8 wt% or 7.0 wt%. etc., wherein the mass ratio of the vanadium pentoxide to the tungsten trioxide is 1:(3.5-7), such as 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5 or 1:7, and the molar ratio of the titanium dioxide to the silicon dioxide is (4-6):1, such as 4:1, 4.2:1, 4.5:1, 4.8:1, 5:1, 5.2:1, 5.5:1, 5.8:1 or 6:1, etc.; but are not limited to the listed values, and other unlisted values ​​within the respective numerical ranges are also applicable.

[0011] In the present invention, according to the application of the SCR denitration catalyst, it has a certain applicable temperature range. If the temperature is too high, it is easy to cause the conversion of the catalyst components and cause deactivation. Therefore, the composition of the denitration catalyst is improved in the present invention, and a composite carrier of titanium dioxide and silicon dioxide is selected, and the ratio of the two is controlled to improve the thermal stability of the carrier to avoid the conversion of the anatase crystal phase to the rutile crystal phase during high-temperature impact and affect the activity. The active components composed of vanadium pentoxide and tungsten trioxide are combined, and the ratio of the two and the proportion of the active components are controlled to make it have higher catalytic denitration activity and a wide applicable temperature range. Even if it is subjected to a high-temperature impact of up to 800°C, it still has the characteristics of high denitration activity; the catalyst has a simple composition and a stable structure, and is suitable for use in efficient and energy-saving denitration processes.

[0012] The following are preferred technical solutions of the present invention, but are not intended to be limitations of the technical solutions provided by the present invention. Through the following technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0013] As a preferred technical solution of the present invention, the mass fraction of the active component in the denitration catalyst is 5.4-6.6wt%, for example, 5.4wt%, 5.5wt%, 5.6wt%, 5.8wt%, 6.0wt%, 6.2wt%, 6.4wt%, 6.5wt% or 6.6wt%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0014] Preferably, the mass fraction of vanadium pentoxide in the active component is 0.8-1.2wt%, for example, 0.8wt%, 0.85wt%, 0.9wt%, 0.95wt%, 1.0wt%, 1.05wt%, 1.1wt%, 1.15wt% or 1.2wt%, etc., but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable; the mass fraction of tungsten trioxide is 4.6-5.4wt%, for example, 4.6wt%, 4.7wt%, 4.8wt%, 4.9wt%, 5.0wt%, 5.1wt%, 5.2wt%, 5.3wt% or 5.4wt%, etc., but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0015] In the present invention, the proportion of active components in the denitration catalyst is an important factor affecting the catalytic activity, especially the selection of the mass fractions of vanadium pentoxide and tungsten trioxide and their ratios. If the mass fraction of vanadium pentoxide is too high or the mass fraction of tungsten trioxide is too low, the surface acidity of the catalyst will be too strong, which may promote side reactions and cause secondary pollution. At the same time, the thermal stability of the catalyst will decrease, and sintering and activity loss of vanadium pentoxide will easily occur at high temperatures, and the mechanical strength and anti-poisoning performance will be reduced. If the mass fraction of vanadium pentoxide is too low or the mass fraction of tungsten trioxide is too high, the number of active centers will decrease or the dispersion efficiency of vanadium pentoxide will decrease, resulting in insufficient denitration activity of the catalyst.

[0016] Preferably, the molar ratio of titanium dioxide to silicon dioxide is (4.5-5.5):1, for example 4.5:1, 4.6:1, 4.8:1, 5:1, 5.2:1, 5.4:1 or 5.5:1, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] In the present invention, the oxides exist in a variety of unstable valence states in the catalyst, which can promote the redox reaction. The denitration catalyst uses titanium dioxide as a carrier. Titanium dioxide is a metal oxide with excellent thermal stability and high specific surface area. At the same time, it can provide abundant oxygen vacancies on the catalyst surface, enhance the interaction with the active components, and improve the catalytic performance; silicon dioxide is a good structural additive that can improve the mechanical strength and thermal stability of the catalyst, and provide a suitable pore structure, which is helpful for the mass transfer and diffusion of the reactants. Since the crystalline phase of titanium dioxide will be converted from the anatase phase to the rutile phase at high temperature, resulting in structural instability, titanium dioxide and silicon dioxide are composed of a composite carrier, so that the catalyst can still maintain the anatase phase after high temperature shock, thereby ensuring the activity of the catalyst.

[0018] Among them, the ratio of titanium dioxide and silicon dioxide is an important factor affecting the stability of the carrier and the activity of the catalyst. If the molar ratio of the two is too high (i.e., the titanium dioxide content is high or the silicon dioxide content is low), the thermal stability of the composite carrier will decrease, and the anatase phase will be more easily transformed into the rutile phase under high temperature conditions, thereby reducing the activity of the catalyst. If the molar ratio of the two is too low (i.e., the silicon dioxide content is high or the titanium dioxide content is low), the dispersion of the active components in the carrier will decrease, the active sites will decrease, and the overall denitrification activity of the catalyst will decrease.

[0019] In a second aspect, the present invention provides a method for preparing the above-mentioned SCR denitration catalyst, the preparation method comprising the following steps:

[0020] (1) mixing a titanium precursor and a silicon precursor, and then adding water to hydrolyze them to obtain a hydrolyzed mixed solution;

[0021] (2) drying and calcining the hydrolyzed mixed solution obtained in step (1) to obtain a denitration catalyst carrier;

[0022] (3) The denitration catalyst carrier obtained in step (2) is mixed with a vanadium precursor, a tungsten precursor, a co-solvent and water, and then dried and calcined to obtain the denitration catalyst.

[0023] As a preferred technical solution of the present invention, the titanium precursor in step (1) includes any one of tetrabutyl titanate, tetraethyl titanate or isopropyl titanate, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of tetrabutyl titanate and tetraethyl titanate, a combination of tetraethyl titanate and isopropyl titanate, a combination of tetrabutyl titanate, tetraethyl titanate and isopropyl titanate, etc. The above precursors all belong to phthalate precursors.

[0024] Preferably, the silicon precursor in step (1) comprises tetraethyl silicate.

[0025] Preferably, the amounts of the titanium precursor and the silicon precursor added in step (1) satisfy a molar ratio of titanium to silicon of (4-6):1, for example 4:1, 4.2:1, 4.5:1, 4.8:1, 5:1, 5.2:1, 5.5:1, 5.8:1 or 6:1, etc., but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] As a preferred technical solution of the present invention, the mass ratio of the amount of water added in step (1) to the total amount of titanium precursor and silicon precursor is (2-4):1, for example 2:1, 2.2:1, 2.5:1, 2.7:1, 3:1, 3.2:1, 3.5:1, 3.8:1 or 4:1, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, the hydrolysis temperature in step (1) is 20-30°C, for example, 20°C, 22°C, 24°C, 25°C, 27°C, 28°C or 30°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] Preferably, the hydrolysis time in step (1) is 8 to 16 h, for example 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h or 16 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] In the present invention, the titanium precursor and the silicon precursor are first mixed, and an eggplant-shaped bottle can be used for stirring for 0.25 to 1 hour, such as 0.25 hours, 0.5 hours, 0.75 hours or 1 hour, to obtain a first mixed solution; deionized water is added to the first mixed solution for hydrolysis, and stirred at room temperature to obtain a hydrolyzed mixed solution.

[0030] The titanium precursor and silicon precursor used in the present invention are both organic precursors, which can more accurately control the reaction process to obtain titanium dioxide and silicon dioxide nanomaterials with uniform particle size and controllable morphology, which are suitable for the preparation of high-performance catalysts.

[0031] As a preferred technical solution of the present invention, the drying in step (2) includes two steps: rotary evaporation drying and oven drying.

[0032] Preferably, the rotary evaporation drying temperature is 50-80°C, for example, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] Preferably, the rotation speed of the rotary evaporation drying is 40 to 80 r / min, for example, 40 r / min, 45 r / min, 50 r / min, 55 r / min, 60 r / min, 65 r / min, 70 r / min, 75 r / min or 80 r / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] Preferably, the rotary evaporation drying pressure is -0.1 to -0.08 MPa, such as -0.1 MPa, -0.095 MPa, -0.09 MPa, -0.085 MPa or -0.08 MPa, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, the drying temperature is 100-140°C, for example 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C or 140°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the drying time is 1 to 4 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] In the present invention, after the hydrolysis mixed solution is separated by rotary evaporation, it is placed in a drying oven for drying to obtain a white solid powder.

[0038] Preferably, the calcination temperature in step (2) is 400-600°C, for example 400°C, 420°C, 450°C, 480°C, 500°C, 520°C, 550°C, 580°C or 600°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the calcination time in step (2) is 3 to 6 hours, for example 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours or 6 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0040] In the present invention, the white solid powder is placed in a muffle furnace and calcined to obtain a denitration catalyst carrier.

[0041] Preferably, the specific surface area of ​​the denitration catalyst carrier in step (2) is 50 to 100 m 2 / g, for example 50m 2 / g, 60m 2 / g, 70m 2 / g, 80m 2 / g, 90m 2 / g or 100m 2 / g, etc., but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] As a preferred technical solution of the present invention, the vanadium precursor in step (3) includes any one of ammonium metavanadate, sodium vanadate or potassium vanadate, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of ammonium metavanadate and sodium vanadate, a combination of sodium vanadate and potassium vanadate, a combination of ammonium metavanadate, sodium vanadate and potassium vanadate, etc.

[0043] Preferably, the tungsten precursor in step (3) comprises any one of ammonium metatungstate, sodium tungstate or potassium tungstate, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of ammonium metatungstate and sodium tungstate, a combination of sodium tungstate and potassium tungstate, a combination of ammonium metatungstate, sodium tungstate and potassium tungstate, etc.

[0044] Preferably, the amounts of the vanadium precursor and the tungsten precursor added in step (3) satisfy the mass ratio of vanadium pentoxide to tungsten trioxide in the denitration catalyst.

[0045] Preferably, the amounts of the vanadium precursor, tungsten precursor and denitration catalyst carrier added in step (3) satisfy the mass fraction of the active components in the denitration catalyst.

[0046] In the present invention, the added mass of the vanadium precursor and the tungsten precursor is calculated according to the ratio of the corresponding mass of vanadium pentoxide and tungsten trioxide after calcination to the total mass of the catalyst. The denitration catalyst prepared under this mass ratio condition has high activity in the temperature range of 400-500°C.

[0047] As a preferred technical solution of the present invention, the co-solvent in step (3) includes an organic acid, and the organic acid includes any one of dihydrated oxalic acid, acetic acid or citric acid, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of dihydrated oxalic acid and sodium acetate, a combination of acetic acid and citric acid, a combination of dihydrated oxalic acid, acetic acid and citric acid, etc.

[0048] Preferably, the mass ratio of the amount of the co-solvent added in step (3) to the vanadium precursor is (1-3):1, for example 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1, 2.8:1 or 3:1, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0049] In the present invention, since the vanadium precursor is not easily soluble, a co-solvent needs to be added to promote the dissolution of ammonium metavanadate. The selected co-solvent is decomposed in the subsequent drying and calcining process and will not affect the components of the catalyst.

[0050] Preferably, the order of adding the raw materials in step (3) is to add water, tungsten precursor, vanadium precursor, co-solvent and denitration catalyst carrier in sequence.

[0051] Preferably, the mixing in step (3) is carried out under water bath stirring conditions.

[0052] Preferably, the stirring temperature in the water bath is 50-70°C, for example, 50°C, 55°C, 60°C, 65°C or 70°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are equally applicable; the stirring time is 4-8h, for example, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h or 8h, but is not limited to the listed values, and other values ​​not listed within the numerical range are equally applicable.

[0053] In the present invention, in order to ensure that the active components of the catalyst prepared by the impregnation method are evenly dispersed on the catalyst surface, the order of adding the raw materials is deionized water, tungsten precursor, vanadium precursor, co-solvent and carrier. The tungsten precursor, vanadium precursor and co-solvent are respectively added to a flask filled with deionized water, and then the carrier is added to obtain a solution with metal particles, which is stirred in a water bath on a magnetic stirrer.

[0054] As a preferred technical solution of the present invention, the drying in step (3) includes two steps: rotary evaporation drying and oven drying.

[0055] Preferably, the rotary evaporation drying temperature is 50-80°C, for example, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0056] Preferably, the rotation speed of the rotary evaporation drying is 40 to 80 r / min, for example, 40 r / min, 45 r / min, 50 r / min, 55 r / min, 60 r / min, 65 r / min, 70 r / min, 75 r / min or 80 r / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0057] Preferably, the rotary evaporation drying pressure is -0.1 to -0.08 MPa, such as -0.1 MPa, -0.095 MPa, -0.09 MPa, -0.085 MPa or -0.08 MPa, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0058] Preferably, the drying temperature is 100-140°C, for example 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C or 140°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0059] Preferably, the drying time is 12 to 24 hours, for example 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours or 24 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0060] In the present invention, after the raw materials are mixed with the carrier, rotary evaporation is carried out on a rotary evaporator under conditions of water bath heating and rotation to obtain a yellow powder sample after the initial moisture is removed. The powder sample is placed in a drying oven for drying and then calcined in a muffle furnace to obtain a denitration catalyst.

[0061] Preferably, the calcination temperature in step (3) is 400-600°C, for example 400°C, 420°C, 450°C, 480°C, 500°C, 520°C, 550°C, 580°C or 600°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0062] Preferably, the calcination time in step (3) is 3 to 6 hours, for example 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours or 6 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0063] Preferably, the denitration catalyst in step (3) is pressed and sieved to obtain denitration catalyst particles with a particle size of 40 to 60 mesh, such as 40 mesh, 45 mesh, 50 mesh, 55 mesh or 60 mesh, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0064] In the present invention, the denitration catalyst prepared by the above process is a crude denitration catalyst. In order to increase the reaction rate, the crude denitration catalyst needs to be tableted and sieved to obtain a denitration catalyst with a smaller particle size and a larger specific surface area.

[0065] In a third aspect, the present invention provides a use of the above-mentioned SCR denitration catalyst, wherein the SCR denitration catalyst is used in a chain grate-rotary kiln process.

[0066] Preferably, the SCR denitration catalyst is used in an embedded denitration process in a grate-rotary kiln process.

[0067] In the present invention, the composition and preparation method of the denitration catalyst are intended to improve the problem of reduced catalytic activity of the existing grate-rotary kiln embedded denitration catalyst when facing high temperature shock. It is also its application field and is applicable to a wide range of denitration temperature, that is, in a denitration environment with local high temperature shock (600-800°C), the denitration efficiency is still high.

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] (1) The present invention improves the composition of the denitration catalyst, selects a composite carrier of titanium dioxide and silicon dioxide, and controls the ratio of the two to improve the thermal stability of the carrier, thereby preventing the catalyst from changing from anatase crystal phase to rutile crystal phase during high temperature shock, thereby affecting its activity;

[0070] (2) The catalyst of the present invention adopts a composite carrier, combined with active components consisting of vanadium pentoxide and tungsten trioxide, and controls the ratio of the two and the proportion of the active components, so that it has high catalytic denitrification activity and a wide applicable temperature range. Even if it is subjected to high temperature shock of up to 800°C, the denitrification activity is still high;

[0071] (3) The catalyst composition and preparation process of the present invention are simple, the structure is stable, it is suitable for high-temperature denitration environment, does not require additional heating, and is highly efficient and energy-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 It is the XRD characterization result diagram of the denitration catalyst in Example 2 of the present invention and Comparative Examples 5-8;

[0073] Figure 2 It is a result diagram of the removal rate of NO in the simulated flue gas in Example 2 of the present invention and Comparative Examples 5-8. DETAILED DESCRIPTION

[0074] In order to better illustrate the present invention and facilitate understanding of the technical solution of the present invention, the present invention is further described in detail below. However, the following embodiments are only simple examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0075] The specific implementation mode of the present invention provides a high temperature resistant SCR denitration catalyst and a preparation method thereof, wherein the denitration catalyst comprises an active component and a carrier, wherein the active component comprises vanadium pentoxide and tungsten trioxide, and the carrier comprises titanium dioxide and silicon dioxide, and the mass fraction of the active component in the denitration catalyst is 5.0 to 7.0 wt %, wherein the mass ratio of the vanadium pentoxide to tungsten trioxide is 1:(3.5 to 7), and the molar ratio of the titanium dioxide to silicon dioxide is (4 to 6):1.

[0076] The preparation method comprises the following steps:

[0077] (1) mixing a titanium precursor and a silicon precursor, and then adding water to hydrolyze them to obtain a hydrolyzed mixed solution;

[0078] (2) drying and calcining the hydrolyzed mixed solution obtained in step (1) to obtain a denitration catalyst carrier;

[0079] (3) The denitration catalyst carrier obtained in step (2) is mixed with a vanadium precursor, a tungsten precursor, a co-solvent and water, and then dried and calcined to obtain the denitration catalyst.

[0080] The following are typical but non-limiting embodiments of the present invention:

[0081] Embodiment 1:

[0082] The present embodiment provides a high temperature resistant SCR denitration catalyst and a preparation method thereof, wherein the denitration catalyst comprises an active component and a carrier, wherein the active component comprises vanadium pentoxide and tungsten trioxide, and the carrier comprises titanium dioxide and silicon dioxide, and the mass fraction of the active component in the denitration catalyst is 5.4wt%, wherein the mass fraction of vanadium pentoxide is 0.8wt%, the mass fraction of tungsten trioxide is 4.6wt%, and the molar ratio of titanium dioxide to silicon dioxide is 4.5:1.

[0083] The preparation method comprises the following steps:

[0084] (1) stirring and mixing tetrabutyl titanate and tetraethyl silicate, wherein the amounts of the tetrabutyl titanate and tetraethyl silicate added are such that the molar ratio of titanium to silicon in the generated carrier is 4.5:1, and then adding water for hydrolysis, wherein the mass ratio of the amount of water added to the total amount of the tetrabutyl titanate and tetraethyl silicate is 2:1, and the hydrolysis temperature is 20° C. and the time is 10 hours to obtain a hydrolyzed mixed solution;

[0085] (2) drying and calcining the hydrolyzed mixed solution obtained in step (1), wherein the drying comprises two steps: rotary evaporation drying and oven drying, wherein the rotary evaporation drying temperature is 60° C., the rotation speed is 60 r / min, and the pressure is -0.1 MPa, the oven drying temperature is 120° C., the time is 2 h, and the calcination temperature is 450° C., the time is 5 h, to obtain a denitration catalyst carrier, wherein the specific surface area of ​​the denitration catalyst carrier is 60 m 2 / g;

[0086] (3) mixing the denitration catalyst carrier obtained in step (2) with ammonium metavanadate, ammonium metatungstate, a co-solvent oxalic acid dihydrate, and water, wherein the order of adding the raw materials is to sequentially add water, ammonium metatungstate, ammonium metavanadate, a co-solvent oxalic acid dihydrate, and a denitration catalyst carrier, wherein the amounts of the ammonium metavanadate, ammonium metatungstate, and denitration catalyst carrier added satisfy the mass fractions of vanadium pentoxide and tungsten trioxide in the denitration catalyst, and the mass ratio of the co-solvent added to the ammonium metavanadate is 2:1, and the mixing is carried out under water bath stirring conditions, the water bath stirring temperature is 60° C., and the time is 6 hours;

[0087] Then it is dried and calcined, the drying includes two steps of rotary evaporation drying and oven drying, the rotary evaporation drying temperature is 60°C, the rotation speed is 60r / min, the pressure is -0.1MPa, the oven drying temperature is 120°C, the time is 20h, the calcination temperature is 450°C, the time is 5h, to obtain the denitration catalyst, the denitration catalyst is pressed and sieved to obtain denitration catalyst particles with an average particle size of 50 mesh.

[0088] Embodiment 2:

[0089] The present embodiment provides a high temperature resistant SCR denitration catalyst and a preparation method thereof, wherein the denitration catalyst comprises an active component and a carrier, wherein the active component comprises vanadium pentoxide and tungsten trioxide, and the carrier comprises titanium dioxide and silicon dioxide, and the mass fraction of the active component in the denitration catalyst is 6.0wt%, wherein the mass fraction of vanadium pentoxide is 1.0wt%, the mass fraction of tungsten trioxide is 5.0wt%, and the molar ratio of titanium dioxide to silicon dioxide is 5:1.

[0090] The preparation method comprises the following steps:

[0091] (1) stirring and mixing tetrabutyl titanate and tetraethyl silicate, wherein the amount of the tetrabutyl titanate and the tetraethyl silicate added is such that the molar ratio of titanium to silicon in the generated carrier is 5:1, and then adding water for hydrolysis, wherein the mass ratio of the amount of the water added to the total amount of the tetrabutyl titanate and the tetraethyl silicate is 3:1, and the hydrolysis temperature is 25° C. and the time is 12 h to obtain a hydrolyzed mixed solution;

[0092] (2) drying and calcining the hydrolyzed mixed solution obtained in step (1), wherein the drying comprises two steps: rotary evaporation drying and oven drying, wherein the rotary evaporation drying is carried out at a temperature of 70° C., a rotation speed of 50 r / min, and a pressure of −0.09 MPa, the oven drying is carried out at a temperature of 100° C., and a time of 4 h, and the calcination is carried out at a temperature of 500° C., and a time of 4 h, to obtain a denitration catalyst carrier, wherein the specific surface area of ​​the denitration catalyst carrier is 75 m 2 / g;

[0093] (3) mixing the denitration catalyst carrier obtained in step (2) with ammonium metavanadate, ammonium metatungstate, a co-solvent oxalic acid dihydrate, and water, wherein the order of adding the raw materials is to sequentially add water, ammonium metatungstate, ammonium metavanadate, a co-solvent oxalic acid dihydrate, and a denitration catalyst carrier, wherein the amounts of the ammonium metavanadate, ammonium metatungstate, and denitration catalyst carrier added satisfy the mass fractions of vanadium pentoxide and tungsten trioxide in the denitration catalyst, and the mass ratio of the co-solvent added to the ammonium metavanadate is 1:1, and the mixing is carried out under water bath stirring conditions, the water bath stirring temperature is 50° C., and the time is 8 hours;

[0094] Then it is dried and roasted, and the drying includes two steps of rotary evaporation drying and oven drying. The rotary evaporation drying temperature is 70°C, the rotation speed is 50r / min, and the pressure is -0.09MPa. The oven drying temperature is 100°C and the time is 24h. The roasting temperature is 500°C and the time is 4h to obtain the denitration catalyst. The denitration catalyst is pressed and sieved to obtain denitration catalyst particles with an average particle size of 40 mesh.

[0095] Embodiment 3:

[0096] The present embodiment provides a high temperature resistant SCR denitration catalyst and a preparation method thereof, wherein the denitration catalyst comprises an active component and a carrier, wherein the active component comprises vanadium pentoxide and tungsten trioxide, and the carrier comprises titanium dioxide and silicon dioxide, and the mass fraction of the active component in the denitration catalyst is 6.6wt%, wherein the mass fraction of vanadium pentoxide is 1.2wt%, the mass fraction of tungsten trioxide is 5.4wt%, and the molar ratio of titanium dioxide to silicon dioxide is 5.5:1.

[0097] The preparation method comprises the following steps:

[0098] (1) stirring and mixing tetrabutyl titanate and tetraethyl silicate, wherein the amounts of the tetrabutyl titanate and tetraethyl silicate added are such that the molar ratio of titanium to silicon in the generated carrier is 5.5:1, and then adding water for hydrolysis, wherein the mass ratio of the amount of water added to the total amount of the tetrabutyl titanate and tetraethyl silicate is 4:1, and the hydrolysis temperature is 30° C. and the time is 16 hours to obtain a hydrolyzed mixed solution;

[0099] (2) drying and calcining the hydrolyzed mixed solution obtained in step (1), wherein the drying comprises two steps: rotary evaporation drying and oven drying, wherein the rotary evaporation drying temperature is 80° C., the rotation speed is 70 r / min, and the pressure is -0.08 MPa, the oven drying temperature is 140° C., the time is 1 h, and the calcination temperature is 550° C., the time is 3.5 h, to obtain a denitration catalyst carrier, wherein the specific surface area of ​​the denitration catalyst carrier is 90 m 2 / g;

[0100] (3) mixing the denitration catalyst carrier obtained in step (2) with ammonium metavanadate, ammonium metatungstate, a co-solvent oxalic acid dihydrate, and water, wherein the order of adding the raw materials is to sequentially add water, ammonium metatungstate, ammonium metavanadate, a co-solvent oxalic acid dihydrate, and a denitration catalyst carrier, wherein the amounts of the ammonium metavanadate, ammonium metatungstate, and denitration catalyst carrier added satisfy the mass fractions of vanadium pentoxide and tungsten trioxide in the denitration catalyst, and the mass ratio of the co-solvent added to the ammonium metavanadate is 3:1, and the mixing is carried out under water bath stirring conditions, the water bath stirring temperature is 70° C., and the time is 4 hours;

[0101] Then it is dried and calcined, the drying includes two steps of rotary evaporation drying and oven drying, the rotary evaporation drying temperature is 80°C, the rotation speed is 70r / min, the pressure is -0.08MPa, the oven drying temperature is 140°C, the time is 12h, the calcination temperature is 550°C, the time is 3.5h, to obtain the denitration catalyst, the denitration catalyst is pressed and sieved to obtain denitration catalyst particles with an average particle size of 60 mesh.

[0102] Embodiment 4:

[0103] The present embodiment provides a high temperature resistant SCR denitration catalyst and a preparation method thereof, wherein the denitration catalyst comprises an active component and a carrier, wherein the active component comprises vanadium pentoxide and tungsten trioxide, and the carrier comprises titanium dioxide and silicon dioxide, and the mass fraction of the active component in the denitration catalyst is 5.0wt%, wherein the mass fraction of vanadium pentoxide is 1.0wt%, the mass fraction of tungsten trioxide is 4.0wt%, and the molar ratio of titanium dioxide to silicon dioxide is 4:1.

[0104] The preparation method comprises the following steps:

[0105] (1) stirring and mixing tetraethyl titanate and tetraethyl silicate, wherein the amount of tetraethyl titanate and tetraethyl silicate added is such that the molar ratio of titanium to silicon in the generated carrier is 4:1, and then adding water for hydrolysis, wherein the mass ratio of the amount of water added to the total amount of tetraethyl titanate and tetraethyl silicate is 2.5:1, the hydrolysis temperature is 20° C., and the time is 12 h, to obtain a hydrolyzed mixed solution;

[0106] (2) drying and calcining the hydrolyzed mixed solution obtained in step (1), wherein the drying comprises two steps: rotary evaporation drying and oven drying, wherein the rotary evaporation drying temperature is 50° C., the rotation speed is 80 r / min, and the pressure is -0.095 MPa, the oven drying temperature is 110° C., and the time is 3 h, and the calcination temperature is 400° C., and the time is 6 h, to obtain a denitration catalyst carrier, wherein the specific surface area of ​​the denitration catalyst carrier is 70 m 2 / g;

[0107] (3) mixing the denitration catalyst carrier obtained in step (2) with sodium vanadate, sodium tungstate, co-solvent acetic acid and water, wherein the order of adding the raw materials is to sequentially add water, sodium tungstate, sodium vanadate, co-solvent acetic acid and denitration catalyst carrier, wherein the amounts of sodium vanadate, sodium tungstate and denitration catalyst carrier added satisfy the mass fractions of vanadium pentoxide and tungsten trioxide in the denitration catalyst, and the mass ratio of the co-solvent added to sodium vanadate is 1.5:1, and the mixing is carried out under water bath stirring conditions, the water bath stirring temperature is 55° C., and the stirring time is 7 hours;

[0108] Then it is dried and calcined, the drying includes two steps of rotary evaporation drying and oven drying, the rotary evaporation drying temperature is 50°C, the rotation speed is 80r / min, the pressure is -0.095MPa, the oven drying temperature is 140°C, the time is 18h, the calcination temperature is 400°C, the time is 6h, to obtain the denitration catalyst, the denitration catalyst is pressed and sieved to obtain denitration catalyst particles with an average particle size of 45 mesh.

[0109] Embodiment 5:

[0110] The present embodiment provides a high temperature resistant SCR denitration catalyst and a preparation method thereof, wherein the denitration catalyst comprises an active component and a carrier, wherein the active component comprises vanadium pentoxide and tungsten trioxide, and the carrier comprises titanium dioxide and silicon dioxide, and the mass fraction of the active component in the denitration catalyst is 7.0wt%, wherein the mass fraction of vanadium pentoxide is 0.9wt%, the mass fraction of tungsten trioxide is 6.3wt%, and the molar ratio of titanium dioxide to silicon dioxide is 6:1.

[0111] The preparation method comprises the following steps:

[0112] (1) isopropyl titanate and tetraethyl silicate are stirred and mixed, wherein the amounts of isopropyl titanate and tetraethyl silicate added are such that the molar ratio of titanium to silicon in the generated carrier is 6:1, and then water is added for hydrolysis, wherein the mass ratio of the amount of water added to the total amount of isopropyl titanate and tetraethyl silicate is 3.5:1, and the hydrolysis temperature is 27° C. and the time is 14 h to obtain a hydrolyzed mixed solution;

[0113] (2) drying and calcining the hydrolyzed mixed solution obtained in step (1), wherein the drying comprises two steps: rotary evaporation drying and oven drying, wherein the rotary evaporation drying is carried out at a temperature of 65° C., a rotation speed of 40 r / min, and a pressure of −0.085 MPa, the oven drying is carried out at a temperature of 130° C., and a time is carried out for 1.5 h, and the calcination is carried out at a temperature of 600° C., and a time is carried out for 3 h, to obtain a denitration catalyst carrier, wherein the specific surface area of ​​the denitration catalyst carrier is 80 m 2 / g;

[0114] (3) mixing the denitration catalyst carrier obtained in step (2) with potassium vanadate, potassium tungstate, co-solvent citric acid and water, wherein the order of adding the raw materials is to sequentially add water, potassium tungstate, potassium vanadate, co-solvent citric acid and denitration catalyst carrier, wherein the amounts of potassium vanadate, potassium tungstate and denitration catalyst carrier added satisfy the mass fractions of vanadium pentoxide and tungsten trioxide in the denitration catalyst, and the mass ratio of the co-solvent added to potassium vanadate is 2.5:1, and the mixing is carried out under water bath stirring conditions, the water bath stirring temperature is 65° C., and the stirring time is 5 h;

[0115] Then it is dried and calcined, and the drying includes two steps: rotary evaporation drying and oven drying. The rotary evaporation drying temperature is 65°C, the rotation speed is 40r / min, and the pressure is -0.085MPa. The oven drying temperature is 130°C and the time is 15h. The calcination temperature is 600°C and the time is 3h to obtain the denitration catalyst. The denitration catalyst is pressed and sieved to obtain denitration catalyst particles with an average particle size of 55 mesh.

[0116] Comparative Example 1:

[0117] This comparative example provides an SCR denitration catalyst and a preparation method thereof. The composition of the denitration catalyst refers to the composition in Example 2, with the only difference being that the mass fraction of vanadium pentoxide in the active component in the denitration catalyst is 0.5wt%, and the reduced proportion is transferred to the carrier.

[0118] The preparation method is similar to the preparation method in Example 2, except that the amount of ammonium metavanadate added in step (3) satisfies the mass fraction of vanadium pentoxide in the denitration catalyst to be 0.5 wt%.

[0119] Comparative Example 2:

[0120] This comparative example provides an SCR denitration catalyst and a preparation method thereof. The composition of the denitration catalyst refers to the composition in Example 2, with the only difference being that the mass fraction of vanadium pentoxide in the active component in the denitration catalyst is 1.6wt%, and the increased proportion is supplemented by the proportion of the carrier.

[0121] The preparation method is similar to the preparation method in Example 2, except that the amount of ammonium metavanadate added in step (3) satisfies the mass fraction of vanadium pentoxide in the denitration catalyst to be 1.6 wt%.

[0122] Comparative Example 3:

[0123] This comparative example provides an SCR denitration catalyst and a preparation method thereof. The composition of the denitration catalyst refers to the composition in Example 2, with the only difference being that the mass fraction of tungsten trioxide in the active component in the denitration catalyst is 3.8wt%, and the reduced proportion is transferred to the carrier.

[0124] The preparation method is similar to the preparation method in Example 2, except that the amount of ammonium metatungstate added in step (3) satisfies the mass fraction of tungsten trioxide in the denitration catalyst to be 3.8 wt%.

[0125] Comparative Example 4:

[0126] This comparative example provides an SCR denitration catalyst and a preparation method thereof. The composition of the denitration catalyst refers to the composition in Example 2, with the only difference being that the mass fraction of tungsten trioxide in the active component in the denitration catalyst is 6.2wt%, and the increased proportion is supplemented by the proportion of the carrier.

[0127] The preparation method is similar to the preparation method in Example 2, except that the amount of ammonium metatungstate added in step (3) satisfies the mass fraction of tungsten trioxide in the denitration catalyst to be 6.2 wt%.

[0128] Comparative Example 5:

[0129] This comparative example provides an SCR denitration catalyst and a preparation method thereof. The composition of the denitration catalyst refers to the composition in Example 2, with the only difference being that the molar ratio of titanium dioxide to silicon dioxide is 3:1.

[0130] The preparation method is similar to the preparation method in Example 2, except that the amount of tetrabutyl titanate and tetraethyl silicate added in step (1) satisfies the molar ratio of titanium to silicon in the generated carrier to be 3:1.

[0131] Comparative Example 6:

[0132] This comparative example provides an SCR denitration catalyst and a preparation method thereof. The composition of the denitration catalyst refers to the composition in Example 2, with the only difference being that the molar ratio of titanium dioxide to silicon dioxide is 10:1.

[0133] The preparation method is similar to the preparation method in Example 2, except that the amount of tetrabutyl titanate and tetraethyl silicate added in step (1) satisfies the molar ratio of titanium to silicon in the generated carrier to be 10:1.

[0134] Comparative Example 7:

[0135] This comparative example provides an SCR denitration catalyst and a preparation method thereof. The composition of the denitration catalyst refers to the composition in Example 2, with the only difference being that the molar ratio of titanium dioxide to silicon dioxide is 20:1.

[0136] The preparation method is similar to the preparation method in Example 2, except that the amount of tetrabutyl titanate and tetraethyl silicate added in step (1) satisfies the molar ratio of titanium to silicon in the generated carrier to be 20:1.

[0137] Comparative Example 8:

[0138] This comparative example provides an SCR denitration catalyst and a preparation method thereof. The composition of the denitration catalyst refers to the composition in Example 2, with the only difference being that the carrier only includes titanium dioxide.

[0139] The preparation method is similar to the preparation method in Example 2, except that tetraethyl silicate is not added in step (1).

[0140] The denitration catalysts prepared in Examples 1-5 and Comparative Examples 1-4 were tested for activity. The process conditions for the activity test included: the simulated flue gas composition was 500 ppm NO, 500 ppm NH3, 16% O2, N2 was used as the carrier gas, the gas flow rate was 200 mL / min, and the space velocity was 110000 h -1 The test temperatures are 400℃, 450℃ and 500℃ respectively; the NO removal rate in the simulated flue gas after the test is shown in Table 1.

[0141] Table 1 NO removal rate in the denitration catalyst activity test of Examples 1-5 and Comparative Examples 1-4

[0142]

[0143] It can be concluded from Table 1 that the denitration catalyst provided in each embodiment can achieve complete removal of NO when the denitration temperature is 400°C; when the denitration temperature is 450°C, the NO removal efficiency is still above 97%; when the denitration temperature is 500°C, the NO removal efficiency can still be maintained at above 80%; it can be seen that the denitration catalyst provided by the present invention has a wide applicable temperature range and has a high catalytic activity in the range of 400-500°C.

[0144] The denitration catalysts provided in each comparative example can still achieve complete removal of NO at a denitration temperature of 400°C; when the denitration temperature rises to 450°C, the NO removal efficiency drops to 90-95%; when the denitration temperature reaches 500°C, the NO removal efficiency cannot reach 80%; it can be seen that the denitration catalyst provided by the present invention requires a suitable vanadium tungsten oxide mass ratio in the catalyst so that the catalyst can achieve the best NO removal efficiency in the temperature range of 400-500°C.

[0145] After the denitration catalysts in Example 2 and Comparative Examples 5-8 were prepared, they were calcined at 800° C. for 10 h, and then the denitration catalysts after calcination were characterized by XRD. The XRD characterization results are as follows: Figure 1 As shown; and then an activity test was performed, the process conditions of the activity test included: the simulated flue gas composition was 500ppm NO, 500ppm NH3, 16% O2, N2 was the carrier gas, the gas flow rate was 200mL / min, and the air velocity was 110000h -1 The test temperature is 150~500℃; the removal rate of NO in the simulated flue gas after the test is as follows Figure 2 shown.

[0146] Figure 1 and Figure 2In VW / xTiySi-800 or VW / Ti-800, x and y represent the molar ratio of titanium element to silicon element in the carrier, x:y, and 800 means that the catalyst is finally calcined at 800°C for 10 hours.

[0147] Depend on Figure 1 It can be seen that when SiO2 is not included in the carrier, after a long period of calcination at 800°C, the catalyst crystal phase changes from anatase phase to rutile phase, resulting in a decrease in catalyst activity. Therefore, adding an appropriate amount of silicon oxide to the carrier helps stabilize the catalyst crystal phase, thereby improving the catalyst's ability to resist high-temperature shock, so that it still has a high NO removal rate.

[0148] Depend on Figure 2 It can be seen that after calcination treatment at 800°C for 10 hours, the denitration catalyst in Example 2 can achieve a NO removal rate of more than 80% at 400-500°C; at the same time, the titanium-silicon molar ratio in the composite carrier has an impact on its SCR catalytic activity. When the titanium-silicon molar ratio in the composite carrier is different, within the temperature range of 400-500°C, the strength of the catalytic activity is Example 2 (VW / 5Ti1Si-800)>Comparative Example 6 (VW / 10Ti1Si-800)>Comparative Example 5 (VW / 3Ti1Si-800)>Comparative Example 8 (VW / Ti-800)≥Comparative Example 7 (VW / 20Ti1Si-800).

[0149] From the above embodiments and comparative examples, it can be seen that the present invention improves the composition of the denitration catalyst, selects a composite carrier of titanium dioxide and silicon dioxide, and controls the ratio of the two to improve the thermal stability of the carrier, so as to avoid the transformation of the anatase crystal phase into the rutile crystal phase during high-temperature shock and affect the activity; the catalyst adopts a composite carrier, combined with an active component composed of vanadium pentoxide and tungsten trioxide, and controls the ratio of the two and the proportion of the active components, so that it has high catalytic denitration activity and a wide applicable temperature range. Even if it is subjected to a high-temperature shock of up to 800°C, the denitration activity is still high; the catalyst composition and preparation process are simple, the structure is stable, it can adapt to high-temperature denitration environment, does not require additional heat supplement, and is highly efficient and energy-saving.

[0150] The applicant declares that the present invention uses the above embodiments to illustrate the detailed products and methods of the present invention, but the present invention is not limited to the above detailed products and methods, that is, it does not mean that the present invention must rely on the above detailed products and methods to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A high temperature resistant SCR denitration catalyst, characterized in that: The denitration catalyst comprises an active component and a carrier, wherein the active component comprises vanadium pentoxide and tungsten trioxide, and the carrier comprises titanium dioxide and silicon dioxide. The mass fraction of the active component in the denitration catalyst is 5.0 to 7.0 wt %, wherein the mass ratio of the vanadium pentoxide to the tungsten trioxide is 1:(3.5 to 7), and the molar ratio of the titanium dioxide to the silicon dioxide is (4 to 6):

1.

2. The SCR denitration catalyst according to claim 1, characterized in that: The mass fraction of the active component in the denitration catalyst is 5.4-6.6wt%; Preferably, the mass fraction of vanadium pentoxide in the active component is 0.8-1.2wt%, and the mass fraction of tungsten trioxide is 4.6-5.4wt%; Preferably, the molar ratio of titanium dioxide to silicon dioxide is (4.5-5.5):

1.

3. The method for preparing the SCR denitration catalyst according to claim 1 or 2, characterized in that: The preparation method comprises the following steps: (1) mixing a titanium precursor and a silicon precursor, and then adding water to hydrolyze them to obtain a hydrolyzed mixed solution; (2) drying and calcining the hydrolyzed mixed solution obtained in step (1) to obtain a denitration catalyst carrier; (3) The denitration catalyst carrier obtained in step (2) is mixed with a vanadium precursor, a tungsten precursor, a co-solvent and water, and then dried and calcined to obtain the denitration catalyst.

4. The preparation method according to claim 3, characterized in that: The titanium precursor in step (1) includes any one of tetrabutyl titanate, tetraethyl titanate or isopropyl titanate, or a combination of at least two thereof; Preferably, the silicon precursor in step (1) comprises tetraethyl silicate; Preferably, the amounts of the titanium precursor and the silicon precursor added in step (1) satisfy a molar ratio of titanium to silicon of (4-6):

1.

5. The preparation method according to claim 3 or 4, characterized in that: In step (1), the mass ratio of the amount of water added to the total amount of the titanium precursor and the silicon precursor is (2-4):1; Preferably, the hydrolysis temperature in step (1) is 20 to 30°C; Preferably, the hydrolysis time in step (1) is 8 to 16 hours.

6. The preparation method according to any one of claims 3 to 5, characterized in that: The drying in step (2) comprises two steps of rotary evaporation drying and oven drying; Preferably, the rotary evaporation drying temperature is 50-80°C; Preferably, the rotation speed of the rotary evaporation drying is 40 to 80 r / min; Preferably, the rotary evaporation drying pressure is -0.1 to -0.08 MPa; Preferably, the drying temperature is 100-140°C; Preferably, the drying time is 1 to 4 hours; Preferably, the calcination temperature in step (2) is 400-600°C; Preferably, the calcination time in step (2) is 3 to 6 hours; Preferably, the specific surface area of ​​the denitration catalyst carrier in step (2) is 50 to 100 m 2 / g.

7. The preparation method according to any one of claims 3 to 6, characterized in that: The vanadium precursor in step (3) includes any one of ammonium metavanadate, sodium vanadate or potassium vanadate, or a combination of at least two thereof; Preferably, the tungsten precursor in step (3) includes any one of ammonium metatungstate, sodium tungstate or potassium tungstate, or a combination of at least two thereof; Preferably, the amount of the vanadium precursor and the tungsten precursor added in step (3) satisfies the mass ratio of vanadium pentoxide to tungsten trioxide in the denitration catalyst; Preferably, the amounts of the vanadium precursor, tungsten precursor and denitration catalyst carrier added in step (3) satisfy the mass fraction of the active components in the denitration catalyst.

8. The preparation method according to any one of claims 3 to 7, characterized in that: The co-solvent in step (3) comprises an organic acid, and the organic acid comprises any one of dihydrated oxalic acid, acetic acid or citric acid, or a combination of at least two thereof; Preferably, the mass ratio of the amount of the co-solvent added in step (3) to the vanadium precursor is (1-3):1; Preferably, the order of adding the raw materials in step (3) is to add water, tungsten precursor, vanadium precursor, co-solvent and denitration catalyst carrier in sequence; Preferably, the mixing in step (3) is carried out under water bath stirring conditions; Preferably, the stirring temperature in the water bath is 50-70° C. and the stirring time is 4-8 h.

9. The preparation method according to any one of claims 3 to 8, characterized in that: The drying in step (3) includes two steps: rotary evaporation drying and oven drying; Preferably, the rotary evaporation drying temperature is 50-80°C; Preferably, the rotation speed of the rotary evaporation drying is 40 to 80 r / min; Preferably, the rotary evaporation drying pressure is -0.1 to -0.08 MPa; Preferably, the drying temperature is 100-140°C; Preferably, the drying time is 12 to 24 hours; Preferably, the calcination temperature in step (3) is 400-600°C; Preferably, the calcination time in step (3) is 3 to 6 hours; Preferably, the denitration catalyst in step (3) is pressed and sieved to obtain denitration catalyst particles with a particle size of 40 to 60 mesh.

10. The use of the SCR denitration catalyst according to claim 1 or 2, characterized in that: The SCR denitration catalyst is used in a grate-rotary kiln process; Preferably, the SCR denitration catalyst is used in an embedded denitration process in a grate-rotary kiln process.

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