SCR (Selective Catalytic Reduction) denitration catalyst as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of denitration catalysts, and provides an SCR denitration catalyst and a preparation method and application thereof. The pore-foaming agent ammonium carbonate, the polymethyl methacrylate powder and the paper pulp fiber are added, the ammonium carbonate is dissolved in water, and nanoscale pores can be formed; the polymethyl methacrylate powder and the paper pulp fiber are insoluble in water in the preparation process and can form micron-sized macropores after being calcined; the SCR denitration catalyst has pores with different pore diameters, the specific surface area, the pore volume and the average pore diameter of the catalyst are increased, target gas enters the pore structure more easily and is adsorbed on the surface of the catalyst for reaction, and the catalytic activity of the catalyst is improved. The montmorillonite molecular sieve is added into the preparation raw materials, so that the proportion of carrier components in the catalyst is adjusted, and the influence of increase of a pore structure on the strength of the catalyst is reduced; meanwhile, the 2-amino-2-methyl-1-propanol and the aluminum hydroxide are added, so that the strength of the catalyst is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of denitration catalysts, and in particular to an SCR denitration catalyst and a preparation method and application thereof. Background Art

[0002] Nitrogen oxides, as one of the important sources of atmospheric pollution, mainly include N2O, NO, N2O2, N2O3, NO2, N2O4, N2O5, etc. Among them, NO and NO2 are the main ones that cause serious atmospheric pollution.

[0003] At present, SNCR or SCR is generally used for flue gas denitrification. SNCR denitrification technology is a selective non-catalytic reduction technology. It is a technology that does not use a catalyst and sprays an amino reducing agent into the furnace to remove NO in the flue gas. X Gas, generating nitrogen and water. SCR denitrification technology is a selective catalytic reduction technology, which sprays an amino reductant into the flue gas upstream of the catalyst, and converts NOx in the flue gas into nitrogen and water through the catalyst.

[0004] At present, the research and development of SCR denitration catalysts by domestic research institutions mainly focuses on improving the activity of catalysts, such as doping with a small amount of precious metal elements such as Ce, Pt, Au, etc. Doping precious metal elements in SCR denitration catalysts has the problem of high cost and easy poisoning of the doped precious metal elements during use. Summary of the invention

[0005] In view of this, the object of the present invention is to provide an SCR denitration catalyst and a preparation method and application thereof. The SCR catalyst of the present invention has excellent catalytic activity, is not prone to poisoning, and has low cost.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: The present invention provides an SCR denitration catalyst, wherein 100 parts by weight of the raw materials for preparation include the following components in parts by weight: 50-70 parts of anatase titanium dioxide, 10-20 parts of montmorillonite molecular sieve, 1-2 parts of ammonium metavanadate, 2-3 parts of ammonium metatungstate, 1-2 parts of glycerol, 1-2.5 parts of glass fiber, 2-4 parts of 2-amino-2-methyl-1-propanol, 2-4 parts of ammonium carbonate, 1-2 parts of polymethyl methacrylate powder, 0.3-0.5 parts of pulp fiber, 0.6-1 parts of hydroxyethyl cellulose, 0.6-1 parts of polyoxyethylene powder, and 5-8 parts of aluminum hydroxide.

[0007] Preferably, the specific surface area of ​​the anatase titanium dioxide is 110-120 m 2 / g, particle size distribution D 50 The specific surface area of ​​the montmorillonite molecular sieve is 80~90m 2 / g, particle size D 90 <18μm.

[0008] Preferably, the particle size of the polymethyl methacrylate powder is 100-500 meshes, and the molecular weight is 40,000-100,000; the particle size of the pulp fiber is 5-200 meshes.

[0009] Preferably, the hydroxyethyl cellulose has a viscosity ranging from 1000 to 1300 mPa·s in terms of a 1% mass concentration aqueous solution, and the molecular weight of the polyoxyethylene powder is 3.6 million to 4.2 million.

[0010] The present invention also provides a method for preparing the SCR denitration catalyst described in the above technical solution, comprising the following steps: Mixing polymethyl methacrylate powder, pulp fibers, ammonium carbonate and water to form a slurry; Mixing montmorillonite molecular sieve, anatase titanium dioxide, aluminum hydroxide, glycerol, ammonium metatungstate, ammonium metavanadate, glass fiber, 2-amino-2-methyl-1-propanol and water to form a slurry; The slurry, mud, hydroxyethyl cellulose and polyoxyethylene powder are mixed and kneaded to obtain a mud material; Extruding the mud material to obtain a catalyst precursor; The catalyst precursor is calcined to obtain the SCR denitration catalyst.

[0011] Preferably, during the preparation of the slurry, the mass ratio of polymethyl methacrylate powder to water is 1:1-3.

[0012] Preferably, the water content of the mud is 30-35wt%.

[0013] Preferably, the moisture content of the mud is 25-30wt%.

[0014] Preferably, the water content of the catalyst precursor is less than or equal to 5wt%; the calcination temperature is 500-500°C, and the insulation time is 24-32h.

[0015] The present invention also provides the use of the SCR denitration catalyst described in the above technical solution or the SCR denitration catalyst prepared by the preparation method described in the above technical solution in air treatment.

[0016] The invention provides an SCR denitration catalyst.

[0017] The present invention adds porogens ammonium carbonate, polymethyl methacrylate powder and pulp fiber, wherein ammonium carbonate is soluble in water and can form nano-scale pores; while polymethyl methacrylate powder and pulp fiber are insoluble in water during the preparation process, and can form micron-scale macropores after calcination; so that the SCR denitration catalyst of the present invention has pores with different pore diameters, improves the specific surface area, pore volume and average pore diameter of the catalyst, makes it easier for the target gas to enter the pore structure, adsorb on the catalyst surface for reaction, and thus improves the catalytic activity of the catalyst; moreover, the added porogen has low cost, which reduces the preparation cost of the SCR denitration catalyst. The present invention adds montmorillonite molecular sieves to the preparation raw materials, adjusts the proportion of the carrier component in the catalyst, and reduces the influence of the increase in the pore structure on the catalyst strength; at the same time, aluminum hydroxide is also beneficial to improve the strength of the catalyst. In addition, the present invention does not introduce precious metals, is not easy to be poisoned, and the catalyst is relatively more stable. In summary, the present invention selects inexpensive ammonium metavanadate and ammonium metatungstate as the active ingredients of the catalyst, and combines the high specific surface area, pore volume and large average pore diameter brought by the pore-forming agent; the SCR denitration catalyst of the present invention has excellent denitration efficiency and low preparation cost; combined with montmorillonite molecular sieve and aluminum hydroxide, the SCR denitration catalyst has excellent compressive strength, which is beneficial to improve the service life of the SCR denitration catalyst. DETAILED DESCRIPTION

[0018] The present invention provides an SCR denitration catalyst, wherein 100 parts by weight of the raw materials for preparation include the following components in parts by weight: 50-70 parts of anatase titanium dioxide, 10-20 parts of montmorillonite molecular sieve, 1-2 parts of ammonium metavanadate, 2-3 parts of ammonium metatungstate, 1-2 parts of glycerol, 1-2.5 parts of glass fiber, 2-4 parts of 2-amino-2-methyl-1-propanol, 2-4 parts of ammonium carbonate, 1-2 parts of polymethyl methacrylate powder, 0.3-0.5 parts of pulp fiber, 0.6-1 parts of hydroxyethyl cellulose, 0.6-1 parts of polyoxyethylene powder, and 5-8 parts of aluminum hydroxide.

[0019] Unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0020] In the present invention, every 100 parts by weight of the raw materials for preparation include 50 to 70 parts by weight of anatase titanium dioxide, and specifically preferably 50 parts by weight, 55 parts by weight, 56 parts by weight, 60 parts by weight, 62.2 parts by weight, 65 parts by weight, 68 parts by weight or 70 parts by weight. In the present invention, the specific surface area of ​​the anatase titanium dioxide is preferably 110 to 120 m 2 / g, particle size distribution D 50 The preferred range is 0.8-1.2 μm. In the present invention, anatase titanium dioxide is the main structure of the SCR denitration catalyst; at the same time, anatase titanium dioxide has a large specific surface area and also serves as a carrier of other active ingredients.

[0021] In the present invention, every 100 parts by weight of the raw materials for preparation include 10 to 20 parts by weight of montmorillonite molecular sieve, and specifically preferably 10 parts by weight, 11 parts by weight, 12 parts by weight, 12.5 parts by weight, 13 parts by weight, 13.5 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 17.5 parts by weight, 18 parts by weight, 19 parts by weight or 20 parts by weight. In the present invention, the specific surface area of ​​the montmorillonite molecular sieve is preferably 80 to 90 m 2 / g, particle size D 90 Preferably <18μm. In the present invention, the main components of the montmorillonite molecular sieve include SiO2, Al2O3 and MgO, and the main function is to form the main structure of the SCR denitration catalyst; at the same time, it can also reduce the thermal expansion coefficient of the SCR denitration catalyst, so that the SCR denitration catalyst has high stability and good thermal shock resistance, and improves the anti-sintering ability of the SCR denitration catalyst in a high temperature environment; in addition, the montmorillonite molecular sieve can also improve the compressive performance of the catalyst.

[0022] In the present invention, every 100 parts by weight of the raw materials for preparation comprises 1 to 2 parts by weight of ammonium metavanadate, and specifically preferably 1 part by weight, 1.1 parts by weight, 1.2 parts by weight, 1.3 parts by weight, 1.4 parts by weight, 1.5 parts by weight, 1.6 parts by weight, 1.7 parts by weight, 1.8 parts by weight, 1.9 parts by weight or 2 parts by weight. In the present invention, the ammonium metavanadate is used as an active substance of the SCR denitration catalyst.

[0023] In the present invention, every 100 parts by weight of the raw materials for preparation include 2 to 3 parts by weight of ammonium metatungstate, and specifically preferably 2 parts by weight, 2.1 parts by weight, 2.2 parts by weight, 2.3 parts by weight, 2.4 parts by weight, 2.5 parts by weight, 2.6 parts by weight, 2.7 parts by weight, 2.8 parts by weight, 2.9 parts by weight or 3 parts by weight. In the present invention, ammonium metatungstate can improve the anti-sintering ability of the SCR denitration catalyst and improve the thermal stability of the SCR denitration catalyst; at the same time, ammonium metatungstate is used as an auxiliary agent, and the cost is greatly reduced compared with the prior art that uses ammonium metamolybdate as an auxiliary agent.

[0024] In the present invention, 1 to 2 parts by weight of glycerol are included per 100 parts by weight of the raw materials, and specifically preferably 1 part by weight, 1.1 parts by weight, 1.2 parts by weight, 1.3 parts by weight, 1.4 parts by weight, 1.5 parts by weight, 1.6 parts by weight, 1.7 parts by weight, 1.8 parts by weight, 1.9 parts by weight or 2 parts by weight. In the present invention, the glycerol is used as a release agent in the extrusion process of the SCR denitration catalyst to reduce the friction between the mud and the extrusion die.

[0025] In the present invention, every 100 parts by weight of the raw materials for preparation include 1 to 2.5 parts by weight of glass fiber, and specifically preferably 1 part by weight, 1.5 parts by weight, 1.8 parts by weight, 2 parts by weight or 2.5 parts by weight. In the present invention, the length of the glass fiber is preferably 5 to 7 mm, and specifically preferably 5 mm, 6 mm or 7 mm; the diameter of the glass fiber is preferably 13 to 16 μm. In the present invention, the glass fiber plays a skeleton role in the SCR denitration catalyst, and improves the structural strength of the SCR denitration catalyst.

[0026] In the present invention, every 100 parts by weight of the raw materials for preparation include 2 to 4 parts by weight of 2-amino-2-methyl-1-propanol, and specifically preferably 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight or 4 parts by weight. In the present invention, the structural formula of the 2-amino-2-methyl-1-propanol is specifically preferably (CH3)2C(NH2)CH2OH. In the present invention, the 2-amino-2-methyl-1-propanol is used as an alkaline regulator, mainly to adjust the pH value of the mud; 2-amino-2-methyl-1-propanol can improve the dispersibility of the powder, so that the powder can be fully mixed even when the amount of water is low. The use of low amounts of water is conducive to improving the density of the mud and ultimately improving the strength of the catalyst.

[0027] In the present invention, 2 to 4 parts by weight of ammonium carbonate are included per 100 parts by weight of the raw materials, and more preferably 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight or 4 parts by weight. In the present invention, the ammonium carbonate acts as an alkaline regulator and is easily decomposed and volatilized by heat, forming nano-scale pores in the final SCR denitration catalyst.

[0028] In the present invention, every 100 parts by weight of the raw materials for preparation include 1 to 2 parts by weight of polymethyl methacrylate powder, and specifically preferably 1 part by weight, 1.1 parts by weight, 1.2 parts by weight, 1.3 parts by weight, 1.4 parts by weight, 1.5 parts by weight, 1.6 parts by weight, 1.7 parts by weight, 1.8 parts by weight, 1.9 parts by weight or 2 parts by weight. In the present invention, the particle size of the polymethyl methacrylate powder is preferably 100 to 500 mesh, and specifically preferably 100 mesh, 200 mesh, 300 mesh, 400 mesh or 500 mesh. In the present invention, the molecular weight of the polymethyl methacrylate powder is preferably 40,000 to 100,000, and specifically preferably 40,000, 45,000, 50,000, 55,000, 60,000, 65,000, 70,000, 75,000, 80,000, 85,000, 90,000, 95,000 or 100,000. In the present invention, the polymethyl methacrylate powder is flammable and has a certain pore-forming ability; it can form micron-sized macropores.

[0029] In the present invention, every 100 parts by weight of the raw materials prepared include 0.3 to 0.5 parts by weight of pulp fiber, and specifically preferably 0.3, 0.35, 0.4, 0.45 or 0.5 parts by weight. In the present invention, the particle size of the pulp fiber is preferably 50 to 200 mesh, and specifically preferably 50, 100, 150 or 200 mesh. In the present invention, the pulp fiber disappears after calcination and can be used as a porogen; at the same time, the pores formed by the pulp fiber are between sodium carboxymethyl cellulose and high-purity fiber cotton, enriching the micron-sized macropores in the SCR denitration catalyst; and working together with polymethyl methacrylate powder, the pore size of the micron-sized macropores in the SCR denitration catalyst is more abundant, which is conducive to the passage of flue gas and improves the denitration efficiency; and can avoid blockage.

[0030] In the present invention, 0.6 to 1 part by weight of hydroxyethyl cellulose is included per 100 parts by weight of the raw materials, and more preferably 0.6, 0.7, 0.8, 0.9 or 1 part by weight. In the present invention, the viscosity of the hydroxyethyl cellulose is preferably 1000 to 1300 mPa·s in terms of a 1% aqueous solution; the viscosity is preferably measured by a Shanghai Jingqi NDJ-53 digital display rotational viscometer. In the present invention, the hydroxyethyl cellulose can adjust the viscosity of the mud, improve the plasticity, and facilitate extrusion molding.

[0031] In the present invention, every 100 parts by weight of the raw materials for preparation include 0.6 to 1 parts by weight of polyoxyethylene powder, and specifically preferably 0.6, 0.7, 0.8, 0.9 or 1 parts by weight. In the present invention, the molecular weight of the polyoxyethylene powder is preferably 3.6 to 4.2 million; the viscosity of the polyoxyethylene powder is preferably 250 to 350 mPa·s in terms of a 0.5% aqueous solution; the viscosity of the polyoxyethylene powder aqueous solution is preferably measured by a Shanghai Jingqi NDJ-53 digital display rotational viscometer. In the present invention, the polyoxyethylene powder is used as a thickener, flocculant, and lubricant, and at the same time, it can also improve the plasticity of the mud.

[0032] In the present invention, 5 to 8 parts by weight of aluminum hydroxide are included per 100 parts by weight of the raw material, and specifically preferably 5 parts by weight, 5.5 parts by weight, 6 parts by weight, 6.5 parts by weight, 7 parts by weight, 7.5 parts by weight or 8 parts by weight. In the present invention, the aluminum hydroxide can provide aluminum element, which is mainly used to reduce the brittleness of the SCR denitration catalyst and improve the strength of the SCR denitration catalyst.

[0033] The present invention also provides a method for preparing the SCR denitration catalyst described in the above technical solution, comprising the following steps: Mixing polymethyl methacrylate powder, pulp fibers, ammonium carbonate and water to form a slurry; Mixing montmorillonite molecular sieve, anatase titanium dioxide, aluminum hydroxide, glycerol, ammonium metatungstate, ammonium metavanadate, glass fiber, 2-amino-2-methyl-1-propanol and water to form a slurry; The slurry, mud, hydroxyethyl cellulose and polyoxyethylene powder are mixed and kneaded to obtain a mud material; Extruding the mud material to obtain a catalyst precursor; The catalyst precursor is calcined to obtain the SCR denitration catalyst.

[0034] The invention mixes polymethyl methacrylate powder, pulp fiber, ammonium carbonate and water to form slurry.

[0035] In the present invention, during the preparation of the slurry, the mass ratio of polymethyl methacrylate powder to water is preferably 1:1-3, specifically preferably 1:1, 1:2 or 1:3.

[0036] In the present invention, the mixing of polymethyl methacrylate powder, pulp fiber, ammonium carbonate and water (referred to as the first mixing) preferably includes the following steps: stirring (referred to as the first stirring) the polymethyl methacrylate powder and dispersing it in water to obtain a polymethyl methacrylate powder dispersion; sequentially adding pulp fiber and ammonium carbonate to the polymethyl methacrylate powder dispersion for a second stirring. In the present invention, the rotation speed of the first stirring is preferably 20 to 30 rpm, specifically preferably 20 rpm, 25 rpm or 30 rpm; the time is preferably 10 to 20 min, specifically preferably 10 min, 15 min or 20 min; the rotation speed of the second stirring is preferably 40 to 50 rpm, specifically preferably 40 rpm, 45 rpm or 50 rpm; the time is preferably 20 to 30 min, specifically preferably 20 min, 25 min or 30 min.

[0037] The invention mixes montmorillonite molecular sieve, anatase titanium dioxide, aluminum hydroxide, glycerol, ammonium metatungstate, ammonium metavanadate, glass fiber, 2-amino-2-methyl-1-propanol and water to form slurry.

[0038] In the present invention, the temperature of mixing montmorillonite molecular sieve, anatase titanium dioxide, aluminum hydroxide, glycerol, ammonium metatungstate, ammonium metavanadate, glass fiber, 2-amino-2-methyl-1-propanol and water (referred to as the second mixing) is preferably 50-60°C. In the present invention, the second mixing is preferably carried out under stirring (referred to as the third stirring); the rotation speed of the third stirring is preferably 50-60rpm, specifically preferably 50rpm, 55rpm or 60rpm. The present invention does not specifically limit the time of the second mixing, as long as the water content of the obtained slurry is 30-35wt%. In the present invention, the second mixing is preferably carried out in a kneader.

[0039] After obtaining the slurry and the mud, the present invention mixes the slurry, the mud, the hydroxyethyl cellulose and the polyoxyethylene powder, and kneads them to obtain the mud.

[0040] In the present invention, the temperature of mixing the slurry, mud, hydroxyethyl cellulose and polyoxyethylene powder (referred to as the third mixing) is preferably 50-60°C, and the time is preferably 0.5-2h. In the present invention, the third mixing is preferably carried out in a stirrer, and the speed of the stirrer is preferably 50-60rpm, specifically preferably 50rpm, 55rpm or 60rpm.

[0041] In the present invention, the kneading temperature is preferably 50-60°C; the kneading is preferably carried out under stirring (fourth stirring), and the fourth stirring speed is preferably 60-80rpm, specifically preferably 60rpm, 70rpm or 80rpm. The present invention does not specifically limit the kneading time, as long as the moisture content of the final mud material is 25-30wt%. In the present invention, the kneading is preferably carried out in a kneader.

[0042] In the present invention, the moisture content of the mud is preferably 25-30wt%.

[0043] After obtaining the mud material, the present invention extrude the mud material to obtain a catalyst precursor.

[0044] In one embodiment of the present invention, the extrusion is preferably performed in an extrusion die.

[0045] In a specific embodiment of the present invention, the catalyst precursor is preferably a 16-hole honeycomb catalyst with an inner wall thickness of 0.94 mm and an outer wall thickness of 1.4 mm.

[0046] In the present invention, the water content of the catalyst precursor is preferably less than or equal to 5 wt %.

[0047] After obtaining the catalyst precursor, the present invention calcines the catalyst precursor to obtain the SCR denitration catalyst.

[0048] In the present invention, the calcination temperature is preferably 500-550°C, specifically preferably 500°C, 510°C, 520°C, 530°C, 540°C or 550°C; the holding time is preferably 24-32h, specifically preferably 24h, 26h, 28h, 30h or 32h.

[0049] The present invention also provides the use of the SCR denitration catalyst described in the above technical solution or the SCR denitration catalyst prepared by the preparation method described in the above technical solution in air treatment.

[0050] The present invention does not specifically limit the application mode of the SCR denitration catalyst, and those skilled in the art may configure it according to actual needs.

[0051] The SCR denitration catalyst provided by the present invention and its preparation method and application are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0052] Source of raw materials Anatase titanium dioxide was purchased from Guangxi Jinmao Titanium Industry Co., Ltd., with a specific surface area of ​​110~120m 2 / g, particle size distribution D 50 The range is 0.8~1.2μm.

[0053] Montmorillonite molecular sieve was purchased from Hubei Sanding Technology Co., Ltd., with a specific surface area of ​​80~90m 2 / g, particle size D 90 <18μm.

[0054] Ammonium metavanadate was purchased from Dalian BoRong High-tech Materials Co., Ltd.; ammonium metatungstate was purchased from Chizhou Zhongmo Catalyst Co., Ltd.; glycerol was purchased from Jinan Haoran Chemical Technology Co., Ltd.; glass fiber was purchased from Yancheng Yanxing Fiberglass Products Co., Ltd., with a fiber length of 6 mm and a diameter of 13-16 μm; 2-amino-2-methyl-1-propanol was purchased from Dow Chemical Company; polymethyl methacrylate powder was purchased from LG Co., Ltd. of South Korea, with a particle size of 200 mesh and a molecular weight of 40,000; pulp fiber was purchased from Guangzhou Xinbang Chemical Co., Ltd., with a particle size of 100 mesh; hydroxyethyl cellulose was purchased from Hebei Hongjin Chemical Co., Ltd., and the viscosity of the 1% hydroxyethyl cellulose aqueous solution was 1000-1300 mPa·s; polyoxyethylene powder was purchased from Shanghai Liansheng Chemical Co., Ltd., with a molecular weight of 3.6-4.2 million; aluminum hydroxide was purchased from Shanghai MacLean Reagent Company.

[0055] Examples and Comparative Examples The raw material formulas for preparing Examples 1 to 5 are shown in Table 1.

[0056] Table 1 Raw material formula for preparation of Examples 1 to 5

[0057] The raw material formulas for the preparation of Comparative Examples 1 to 5 are shown in Table 2.

[0058] Table 2 Preparation raw material formula of comparative examples 1 to 5

[0059] The preparation method of the catalysts obtained in the above Examples 1 to 5 and Comparative Examples 1 to 5 comprises the following steps: The polymethyl methacrylate powder was dispersed in deionized water (the mass ratio of the polymethyl methacrylate powder to the deionized water was 1:2) and stirred at 25 rpm for 15 min to mix the two. Then, pulp fiber and ammonium carbonate were added in sequence and stirred at 45 rpm for 25 min to obtain a slurry.

[0060] Montmorillonite molecular sieve, anatase titanium dioxide, aluminum hydroxide, glycerol, ammonium metatungstate, ammonium metavanadate, glass fiber, 2-amino-2-methyl-1-propanol and deionized water are added to a kneader, the temperature is raised to 50-60°C, and stirred at 55 rpm to obtain a slurry with a water content of 30-40 wt%.

[0061] Put the slurry into all the mud materials, add hydroxyethyl cellulose and polyoxyethylene powder, use a mixer with heating capability to stir at 55rpm for 1h, control the temperature at 50-60℃ to make the two mixed evenly; then place the evenly mixed materials in a kneading machine under heating (50-60℃) and stir at 70rpm to evaporate water to obtain mud with a moisture content of 25-30wt%; take out the mud and seal it with plastic wrap.

[0062] The mud is put into a honeycomb catalyst extruder and extruded through a die to form a honeycomb catalyst, and a 16-hole honeycomb catalyst with an inner wall thickness of 0.94 mm and an outer wall thickness of 1.4 mm is extruded; the extruded honeycomb catalyst is put into a drying room for dehydration and drying until the moisture content is less than 5wt%, thereby obtaining a catalyst precursor.

[0063] The catalyst precursor was placed in a mesh belt kiln for calcination at a temperature of 500°C and a calcination time of 28 hours to finally obtain a honeycomb SCR denitration catalyst.

[0064] Comparative Example 6 Add 55 parts by weight of TiO2, 2 parts by weight of clay and 3 parts by weight of ammonium heptamolybdate into a mixer and dry-mix at a low speed of 150 rpm for 10 min; add 20 parts by weight of deionized water and stir at a high speed of 750 rpm for 20 min; add 1 part by weight of ammonium metavanadate-MEA solution and stir at a high speed of 750 rpm for 10-20 min; add 2 parts by weight of ammonia water and stir at a high speed of 750 rpm for 20 min; add 2 parts by weight of glass fiber and 0.5 parts by weight of CMC and stir at a high speed of 750 rpm for 20 min; finally add 15 parts by weight of deionized water and stir in the reverse direction at a low speed of 150 rpm to mix evenly; let it stand for 30 min; add 2 parts by weight of ammonium carbonate and stir at a low speed of 150 rpm for 15 min to remove moisture, and control the moisture content of the mud to 30% and the pH value to 8.4.

[0065] The mud is put into a honeycomb catalyst extruder and extruded through a die to form a honeycomb catalyst, and a 16-hole honeycomb catalyst with an inner wall thickness of 0.94 mm and an outer wall thickness of 1.4 mm is extruded; the extruded honeycomb catalyst is put into a drying room for dehydration and drying until the moisture content is less than 5wt%, thereby obtaining a catalyst precursor.

[0066] The catalyst precursor was placed in a mesh belt kiln for calcination at a temperature of 520°C and a calcination time of 28 hours to finally obtain a honeycomb SCR denitration catalyst.

[0067] Performance Testing (1) The main components of the obtained catalyst were tested by XRF spectroscopy. The results are shown in Table 3. Non-important components are not listed.

[0068] Table 3 Main components of the catalysts obtained in the examples and comparative examples

[0069] It can be seen from Table 3 that each component changes with the change of the added amount, and there is no other abnormal situation. It should be noted that SO3 in the components comes from titanium dioxide, and CaO and MgO come from montmorillonite powder.

[0070] (2) The specific surface area, pore volume and average pore diameter of the obtained catalyst were determined by the BET method. The results are shown in Table 4.

[0071] Table 4 Specific surface area, pore volume and average pore diameter of the catalysts obtained in the examples and comparative examples

[0072] It can be seen from Table 4 that in Examples 1 to 5, the pore-forming agent (ammonium carbonate, polymethyl methacrylate powder, pulp fiber) gradually decreases, which is reflected in the test data that the pore volume gradually decreases. The pore volume is also called pore volume, which is the total volume of pores per unit mass of porous solids; the average pore diameter gradually decreases. In Examples 1 to 5, the difference in specific surface area is not obvious. From the composition, it can be seen that titanium oxide gradually increases. Because the specific surface area of ​​titanium oxide is greater than that of montmorillonite molecular sieve, the specific surface area of ​​Example 5 is relatively high, but because the pore volume increases, that is, the pore structure in the catalyst increases, it is easy to increase the specific surface area. Therefore, with the increase of pore-forming agent, the specific surface area does not decrease significantly with the decrease of titanium oxide ratio, but the specific surface areas of Examples 1, 2 and 3, 4 are close. Richer specific surface area and pore structure are beneficial to improving denitrification efficiency. From Comparative Examples 1 to 3, it can be found that the three pore-forming agents have a greater impact on the average pore diameter. With the reduction of pore-forming agents, the average pore diameter gradually decreases. Comparative Example 6 has a higher pore volume but a lower pore diameter. This is because Comparative Example 6 is different from other embodiments and comparative examples. Its active component contains molybdenum element, which is beneficial to improving denitrification activity, and tungsten element is beneficial to improving the product's anti-sintering ability. The pore-forming material only uses ammonium carbonate. This catalyst has a large number of tiny pore structures, so the relative average pore diameter is low, but the pore volume is high. With the deepening of research, it is believed that the tiny pore diameter is easily blocked during actual use, which is not conducive to long-term use.

[0073] (3) Denitrification efficiency (temperature range 280~380℃) The prepared catalyst works at a flue gas temperature of 300-370°C. The test conditions are based on the GBT31587-2015 honeycomb flue gas denitrification catalyst as the reference standard. X 500 mg / Nm 3 , 4v.%O2, 30mg / Nm 3 SO2, airspeed 13000h -1 Under the conditions, the aging time is 30 hours, and the gas composition and content are tested every 1 hour. The results are shown in Table 5.

[0074] Table 5 Denitration efficiency of catalysts obtained in Examples and Comparative Examples

[0075] From Table 5, it can be seen that, in combination with Examples 1 to 5, it can be seen that with the increase of V2O5 content, the denitration ability of the catalyst is stronger, because vanadium is the main active component for denitration. It should be noted that in Comparative Example 1 and Example 2, Comparative Example 2 and Example 3, and Comparative Example 3 and Example 4, due to the lack of pore-forming agent, the denitration efficiency of the catalyst obtained in the comparative example is lower than that of the ordinary sample. Combined with the pore volume and average pore diameter data, this proves that a certain pore structure is beneficial to improving the denitration efficiency.

[0076] (4) Compressive strength test The compressive strength of the honeycomb SCR denitration catalyst was tested using GBT31587, a national standard of the People's Republic of China. The results are shown in Table 6.

[0077] Table 6 Compressive strength test data of catalysts obtained in Examples and Comparative Examples

[0078] It can be seen from Table 6 that the compressive strength of Example 4 is the best. From the perspective of the carrier component composition, Table 3 shows that the ratio of titanium, silicon, and aluminum elements affects the structural strength of the catalyst. By comparing Examples 5 and 6, it can be further explained that aluminum elements (mainly derived from aluminum hydroxide) and silicon elements (mainly derived from montmorillonite molecular sieves) can increase the compressive strength. The silicon element has a more obvious effect on increasing the strength, and the aluminum element tends to reduce the brittleness of the catalyst and improve the wear resistance. It should be noted that these compressive data are greater than the national standard requirements, radial 0.4MPa, axial 2.0MPa. The ingredients provided by the present invention can provide a rich pore structure while improving the compressive strength of the catalyst. Comparing Example 4 and Example 4, it is also shown that a certain amount of aluminum salt has an effect on the structural strength of the catalyst. Comparing Example 5 and Example 4, it can also be explained that montmorillonite molecular sieves can improve the compressive strength.

[0079] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An SCR denitration catalyst, characterized in that: Every 100 parts by weight of the raw materials for preparation include the following components in parts by weight: 50-70 parts of anatase titanium dioxide, 10-20 parts of montmorillonite molecular sieve, 1-2 parts of ammonium metavanadate, 2-3 parts of ammonium metatungstate, 1-2 parts of glycerol, 1-2.5 parts of glass fiber, 2-4 parts of 2-amino-2-methyl-1-propanol, 2-4 parts of ammonium carbonate, 1-2 parts of polymethyl methacrylate powder, 0.3-0.5 parts of pulp fiber, 0.6-1 parts of hydroxyethyl cellulose, 0.6-1 parts of polyoxyethylene powder, and 5-8 parts of aluminum hydroxide.

2. The SCR denitration catalyst according to claim 1, characterized in that: The specific surface area of ​​the anatase titanium dioxide is 110-120 m 2 / g, particle size distribution D 50 The specific surface area of ​​the montmorillonite molecular sieve is 80~90m 2 / g, particle size D 90 <18μm.

3. The SCR denitration catalyst according to claim 1, characterized in that: The particle size of the polymethyl methacrylate powder is 100-500 meshes, and the molecular weight is 40,000-100,000; the particle size of the pulp fiber is 50-200 meshes.

4. The SCR denitration catalyst according to claim 1, characterized in that: The hydroxyethyl cellulose has a viscosity ranging from 1000 to 1300 mpa·s in terms of a 1% aqueous solution, and the molecular weight of the polyoxyethylene powder is 3.6 million to 4.2 million.

5. The method for preparing the SCR denitration catalyst according to any one of claims 1 to 4, characterized in that: The following steps are involved: Mixing polymethyl methacrylate powder, pulp fibers, ammonium carbonate and water to form a slurry; Mixing montmorillonite molecular sieve, anatase titanium dioxide, aluminum hydroxide, glycerol, ammonium metatungstate, ammonium metavanadate, glass fiber, 2-amino-2-methyl-1-propanol and water to form a slurry; The slurry, mud, hydroxyethyl cellulose and polyoxyethylene powder are mixed and kneaded to obtain a mud material; Extruding the mud material to obtain a catalyst precursor; The catalyst precursor is calcined to obtain the SCR denitration catalyst.

6. The preparation method according to claim 5, characterized in that: During the preparation of the slurry, the mass ratio of polymethyl methacrylate powder to water is 1:1-3.

7. The preparation method according to claim 5, characterized in that: The water content of the mud is 30-35wt%.

8. The preparation method according to claim 5, characterized in that: The moisture content of the mud is 25-30wt%.

9. The preparation method according to claim 5, characterized in that: The water content of the catalyst precursor is less than or equal to 5wt%; the calcination temperature is 500-550°C, and the insulation time is 24-32h.

10. Use of the SCR denitration catalyst according to any one of claims 1 to 4 or the SCR denitration catalyst prepared by the preparation method according to any one of claims 5 to 9 in air treatment.

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