Vanadium honeycomb type ultralow-temperature denitration catalyst as well as preparation method and application thereof

Abstract

The invention relates to a vanadium honeycomb ultralow-temperature denitration catalyst and a preparation method and application thereof.The preparation method comprises the steps that 1, vanadium salt, molybdenum salt, nanometer titania and a water repellent agent are mixed, organic acid is added for kneading, and first pug is obtained; (2) carrying out first forming treatment on the first pug, drying and roasting to obtain catalyst particles; and (3) crushing the catalyst particles, mixing and kneading the crushed catalyst particles with a rare earth modifier and an additive, and carrying out second molding treatment, drying and calcining on the obtained second pug to obtain the vanadium-series honeycomb ultralow-temperature denitration catalyst. The prepared catalyst can still maintain high denitration efficiency (larger than or equal to 90%) at the temperature of 160 DEG C or below, ultralow-temperature denitration is achieved, the low-temperature flue gas treatment requirement is met, SO2 oxidation and sulfate generation are inhibited by adding the rare earth modifier and designing the hydrophobic layer, meanwhile, contact between water molecules and active sites is reduced, and the catalyst has the advantages of being low in cost and high in efficiency in the flue gas environment containing water and sulfur. And the denitration efficiency of the catalyst is still kept above 80%.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of environmental protection catalyst development and air pollutant control technology, and particularly relates to a vanadium-based honeycomb ultra-low temperature denitration catalyst and a preparation method and application thereof. BACKGROUND

[0002] With the enhancement of global environmental awareness, the emission standards of NOx in industrial flue gas are increasingly strict in various countries. For example, the NOx emission limit value of newly built boilers in key regions in China has been reduced to 50 mg / m3 or even 30 mg / m3. Traditional high-nitrogen combustion technology (LNB) and selective non-catalytic reduction (SNCR) technology are inefficient, and thus need to rely on selective catalytic reduction (SCR) technology to achieve efficient denitration. x x 3 3 . Traditional high-nitrogen combustion technology (LNB) and selective non-catalytic reduction (SNCR) technology are inefficient, and thus need to rely on selective catalytic reduction (SCR) technology to achieve efficient denitration.

[0003] In the non-electricity industry such as biomass incineration, cement, and glass, the flue gas temperature is usually lower than 200℃, and even decreases to below 150℃ after dust removal and wet desulfurization. The traditional vanadium-titanium catalyst (V2O5-WO3 / TiO2) has an active temperature window of 280-420℃, and thus needs to reheat the flue gas, resulting in high operation cost and increased carbon emissions. In addition, the industrial flue gas often contains high concentrations of SO2 (such as 1500 ppm) and water (such as 5-30%), and SO2 is easily oxidized to SO3, which reacts with NH3 to form ammonium bisulfate (ABS). The traditional catalyst is prone to activity decline or even deactivation at low temperatures due to the deposition of ammonium sulfate salt or the capillary condensation of water vapor. In addition, the active components (such as vanadium) of some catalysts will react with sulfuric acid and be lost in a high-sulfur environment. At low temperatures, H2O competes with NH3 for adsorption, reducing the adsorption amount of NH3 on the catalyst. In addition, alkali metals (such as K and Na) in the flue gas occupy the acidic active sites, further weakening the catalytic efficiency, and resulting in a shortened catalyst life.

[0004] CN116870922A discloses an ultra-low temperature denitration catalyst and a preparation method thereof. The catalyst is prepared from raw materials including nano-nickel ferrite powder, nano-titanium dioxide-graphene powder, ammonium metavanadate, ammonium niobium oxalate, stannous chloride, zirconium sulfate, zirconium oxychloride, rare earth metal salt, ammonium metatungstate, ammonium heptamolybdate, chopped glass fiber, silane coupling agent alcohol solution, titanate coupling agent, hydroxypropyl methyl cellulose (HPMC), acesulfame, polyethylene oxide, and magic acid. The catalyst is added with various auxiliary reagents to improve the denitration efficiency, which makes the operation more complex, increases the production cost, and makes the production efficiency low. In addition, the denitration efficiency is low at a temperature below 200℃.

[0005] ​​​​CN119303562A discloses a preparation method and application of an ultra-low temperature denitration catalyst. The catalyst is prepared by stirring the calcined molybdenum oxide and titanium white powder into a vanadium salt complex solution, drying, and calcining to obtain an ultra-low temperature denitration catalyst. The denitration performance of the catalyst at 150 DEG C and 170 DEG C can only reach 80%, and due to the instability of the complex chemical properties, there is great danger, and there is a certain safety risk in industrial production.

[0006] CN118719110A discloses a porous spherical water-resistant sulfur-resistant low-temperature SCR denitration catalyst and a preparation method thereof. The catalyst carrier, active component adsorbed on the surface of the carrier and hydrophobic material cavity, nitrogen-containing group grafted to carboxyl or lactone group on the anatase titanium dioxide treated with oxalic acid to promote oxidation of NO, and the hydrophobic cavity with a barrel-shaped structure composed of hydroxyl groups on the surface. The catalyst carrier body includes an anatase titanium dioxide substrate, the active component and the nitrogen-containing group are uniformly distributed above the carrier, and the hydrophobic layer is formed by arranging the hydrophobic cavity in order. The catalyst has high denitration efficiency at 200 DEG C, and the use temperature is high.

[0007] In order to solve the problem of low catalytic efficiency of traditional denitration catalyst at low temperature due to low flue gas temperature in steel plants, glass plants and the like, a new low-temperature denitration catalyst is urgently needed, which can still maintain high catalytic activity under the condition that the flue gas contains part of water and sulfide, avoid catalyst poisoning or blockage, and prolong the service life of the catalyst. SUMMARY

[0008] To solve the above technical problems, the present application provides a vanadium-based honeycomb ultra-low temperature denitration catalyst and its preparation method and application. The catalyst prepared by the present application can maintain high denitration efficiency (≥90%) below 160 DEG C, realize ultra-low temperature denitration, meet the demand of low-temperature flue gas treatment, and by adding rare earth modifier and designing hydrophobic layer, inhibit SO2 oxidation and sulfate generation, and reduce the contact of water molecules with active sites. In the flue gas environment containing water and sulfur, the denitration efficiency of the catalyst is still maintained above 80%.

[0009] To achieve this purpose, the present application adopts the following technical solutions:

[0010] In a first aspect, the present application provides a preparation method of a vanadium-based honeycomb ultra-low temperature denitration catalyst, which comprises:

[0011] (1) mixing vanadium salt, molybdenum salt, nano titanium dioxide and hydrophobic agent, then adding organic acid for kneading to obtain a first mud;

[0012] (2) performing first molding treatment, drying and calcining on the first mud to obtain catalyst particles;

[0013] (3) crushing the catalyst particles, mixing with the rare earth modifier and the additive, and then kneading to obtain a second slurry, and then performing a second molding process, drying and calcination to obtain the vanadium-based honeycomb ultra-low temperature denitration catalyst.

[0014] The preparation method of the present application mixes the active components vanadium salt, molybdenum salt, nano-titanium dioxide and hydrophobic agent, and forms a hydrophobic layer on the surface of the catalyst through the preparation process of kneading, extruding, drying and calcination, reduces the contact between water molecules and active sites, and keeps the denitration efficiency of the catalyst at above 80% in a flue gas environment containing water and sulfur.

[0015] As a preferred technical solution of the present application, the vanadium salt in step (1) includes ammonium metavanadate.

[0016] Preferably, the molybdenum salt includes ammonium heptamolybdate.

[0017] Preferably, the hydrophobic agent includes any one or a combination of at least two of expanded graphite, siloxane or nitrogen methyl silane, and typical but non-limiting examples of the combination include expanded graphite and siloxane, expanded graphite and nitrogen methyl silane, and siloxane and nitrogen methyl silane.

[0018] Preferably, the organic acid includes any one or a combination of at least two of oxalic acid, glacial acetic acid or citric acid, and typical but non-limiting examples of the combination include oxalic acid and glacial acetic acid, oxalic acid and citric acid, and glacial acetic acid and citric acid.

[0019] The present application can form a hydrophobic layer on the surface of the catalyst after drying and calcination by adding a hydrophobic agent, thereby significantly improving the water resistance and denitration performance of the catalyst.

[0020] As a preferred technical solution of the present application, the mass ratio of the vanadium salt, molybdenum salt, nano-titanium dioxide and hydrophobic agent is (1-5):(1-5):(85-97):(1-5), for example 1:1:97:5, 2:2:94:2, 3:3:91:3, 4:4:88:4, 5:5:85:5, etc., but not limited to the listed values, and other values not listed within the above value range are also applicable.

[0021] As a preferred technical solution of the present application, the drying temperature in step (2) is 100-110°C, for example 100°C, 102°C, 104°C, 106°C, 108°C, 110°C, etc., but not limited to the listed values, and other values not listed within the above value range are also applicable.

[0022] The drying time is 10-12h. For example, 10h, 10.5h, 11h, 12h, etc., but not limited to the listed values, and other values not listed within the above value range are also applicable.

[0023] Preferably, the temperature of the calcination is 450-500℃, such as 450℃, 460℃, 470℃, 480℃, 490℃, 500℃, etc., but not only limited to the listed values, other values not listed in the above value range are also applicable.

[0024] The time of the calcination is 4-6h, such as 4h, 4.5h, 5h, 5.5h, 6h, etc., but not only limited to the listed values, other values not listed in the above value range are also applicable.

[0025] Preferably, the heating rate of the calcination is 6-8℃ / min, such as 6℃ / min, 6.5℃ / min, 7℃ / min, 7.5℃ / min, 8℃ / min, etc., but not only limited to the listed values, other values not listed in the above value range are also applicable.

[0026] As a preferred technical solution of the present application, the particle size of the broken catalyst particles in step (3) is ≤325 mesh, such as 325 mesh, 320 mesh, 315 mesh, 310 mesh, 305 mesh, 300 mesh, etc., but not only limited to the listed values, other values not listed in the above value range are also applicable.

[0027] Preferably, the rare earth modifier includes basic cerium carbonate.

[0028] By adding basic cerium carbonate as a rare earth modifier, the present application can form a vanadium-based honeycomb catalyst with high porosity after mixing and kneading with the catalyst particles, drying and calcination, and the basic cerium carbonate is also decomposed into cerium oxide after calcination, so that the formed catalyst has sulfur resistance. Compared with traditional vanadium-titanium catalyst, the catalyst of the present application has significantly improved low-temperature adaptability, and also has water and sulfur resistance.

[0029] As a preferred technical solution of the present application, the additive in step (3) includes a forming aid, a binder, a lubricant and a humectant.

[0030] Preferably, the forming aid includes any one of glass fiber, pulp fiber or lactic acid.

[0031] Preferably, the binder includes any one of starch, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose or carboxymethyl cellulose, or a combination of at least two of them, such as starch and methyl cellulose, methyl cellulose and hydroxypropyl methyl cellulose, hydroxypropyl methyl cellulose and hydroxyethyl cellulose, hydroxyethyl cellulose and carboxymethyl cellulose, etc.

[0032] Preferably, the lubricant includes stearic acid.

[0033] Preferably, the humectant comprises glycerin.

[0034] Preferably, the mass ratio of the catalyst particles, the rare earth modifier, the forming aid, the binder, the lubricant and the humectant is (87-95):(1-5):(1-2):(1-2):(1-2):(1-2), such as 95:1:1:1:1:1, 90:2:2:2:2:2, 89:3:2:2:2:2, 88:4:2:2:2:2, 91:5:1:1:1:1, 87:5:2:2:2:2, etc., but not limited to the listed values, and other values not listed within the above numerical range are also applicable.

[0035] As a preferred technical solution of the present application, the drying in step (3) comprises first drying and second drying.

[0036] Preferably, the temperature of the first drying is 40-60℃, such as 40℃, 45℃, 50℃, 55℃, 60℃, etc., but not limited to the listed values, and other values not listed within the above numerical range are also applicable.

[0037] The time of the first drying is 24-36h, such as 24h, 26h, 28h, 30h, 32h, 34h, 36h, etc., but not limited to the listed values, and other values not listed within the above numerical range are also applicable.

[0038] Preferably, the temperature of the second drying is 120-130℃, such as 120℃, 122℃, 124℃, 126℃, 128℃, 130℃, etc., but not limited to the listed values, and other values not listed within the above numerical range are also applicable.

[0039] The time of the second drying is 4-6h, such as 4h, 4.5h, 5h, 5.5h, 6h, etc., but not limited to the listed values, and other values not listed within the above numerical range are also applicable.

[0040] As a preferred technical solution of the present application, the temperature of the calcination in step (3) is 400-500℃, such as 400℃, 420℃, 440℃, 460℃, 480℃, 500℃, etc., but not limited to the listed values, and other values not listed within the above numerical range are also applicable.

[0041] The time of the calcination is 4-6h, such as 4h, 4.5h, 5h, 5.5h, 6h, etc., but not limited to the listed values, and other values not listed within the above numerical range are also applicable.

[0042] Preferably, the heating rate of the calcination is 5-8℃ / min, such as 5℃ / min, 5.5℃ / min, 6℃ / min, 6.5℃ / min, 7℃ / min, 7.5℃ / min, 8℃ / min, etc., but not limited to the listed values, and other values not listed in the above value range are also applicable.

[0043] In a second aspect, the present application provides a vanadium-based honeycomb ultra-low temperature denitration catalyst, which is prepared by the preparation method of the first aspect.

[0044] In a third aspect, the present application provides the use of the vanadium-based honeycomb ultra-low temperature denitration catalyst of the second aspect in the coking, power generation, steel, glass, ceramic, and cement industries.

[0045] It should be noted that when the catalyst of the present application is used for coke oven flue gas denitration in the coking industry, it can enhance sulfur corrosion resistance and reduce ammonium salt deposition due to its sulfur-resistant design and hydrophobic structure; when it is used in waste incineration power plants, it can solve the problem of low-temperature flue gas denitration; when it is used in the steel industry for high-dust tail gas denitration, the high porosity of the honeycomb body can reduce the risk of ash deposition; when it is used in high-alkali metal flue gas of glass, ceramic, and cement kilns, the formula introduces cerium and other additives to neutralize the poisoning effect of alkali metals on vanadium active sites.

[0046] Compared with the prior art, the present application has at least the following beneficial effects:

[0047] (1) The present application forms a hydrophobic layer on the surface of the catalyst by adding a hydrophobic agent, reducing the contact between water molecules and active sites, and maintaining the denitration efficiency of the catalyst at more than 80% in a flue gas environment containing water and sulfur;

[0048] (2) The present application can prepare a vanadium-based honeycomb catalyst with high porosity by adding a rare earth modifier, which can make the catalyst have sulfur resistance after high-temperature decomposition;

[0049] (3) The present application prepares a low-temperature denitration catalyst with high porosity, water resistance, and sulfur resistance through the processes of kneading, extruding, drying, and calcination, which has a simple preparation process, low cost, and is suitable for industrial large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 is a process flow chart of a preparation method of a vanadium-based honeycomb ultra-low temperature denitration catalyst provided by the present application.

[0051] Figure 2 is the denitration efficiency of the catalyst prepared in Example 1 under different test conditions. DETAILED DESCRIPTION

[0052] The technical solutions of the present application are further illustrated below in conjunction with the accompanying drawings and through specific embodiments. However, the following examples are merely simple examples of the present application and do not represent or limit the protection scope of the present application, and the protection scope of the present application is subject to the claims.

[0053] Embodiment 1

[0054] The present embodiment provides a preparation method of a vanadium-based honeycomb ultra-low temperature denitration catalyst, which comprises the following steps:

[0055] (1) Ammonium metavanadate, ammonium heptamolybdate, nanometer titanium dioxide and expanded graphite are mixed, and oxalic acid is added for kneading to obtain a first mud; the mass ratio of the ammonium metavanadate, ammonium heptamolybdate, nanometer titanium dioxide and expanded graphite is 1:1:97:1;

[0056] (2) The first mud is extruded, dried at 100℃ for 12h, then heated to 450℃ at a heating rate of 6℃ / min and kept for 6h to obtain catalyst particles;

[0057] (3) The catalyst particles are crushed to 325 mesh, mixed and kneaded with basic cerium carbonate, glass fiber, starch, stearic acid and glycerol; the mass ratio of the catalyst particles, basic cerium carbonate, glass fiber, starch, stearic acid and glycerol is 95:1:1:1:1:1; the obtained second mud is vacuum extruded, dried at 60℃ for 24h, then dried at 120℃ for 6h, and then heated to 400℃ at a heating rate of 5℃ / min and kept for 6h for calcination treatment to obtain the vanadium-based honeycomb ultra-low temperature denitration catalyst.

[0058] Embodiment 2

[0059] The present embodiment provides a preparation method of a vanadium-based honeycomb ultra-low temperature denitration catalyst, which comprises the following steps:

[0060] (1) Ammonium metavanadate, ammonium heptamolybdate, nanometer titanium dioxide and siloxane are mixed, and glacial acetic acid is added for kneading to obtain a first mud; the mass ratio of the ammonium metavanadate, ammonium heptamolybdate, nanometer titanium dioxide and siloxane is 5:5:85:5;

[0061] (2) The first mud is extruded, dried at 110℃ for 10h, then heated to 500℃ at a heating rate of 8℃ / min and kept for 4h for calcination treatment to obtain catalyst particles;

[0062] (3) crushing the catalyst particles to 320 mesh, and mixing and kneading with basic cerium carbonate, pulp fiber, methyl cellulose, stearic acid, glycerol; the mass ratio of the catalyst particles, basic cerium carbonate, pulp fiber, methyl cellulose, stearic acid, glycerol is 87:5:2:2:2:2; the obtained second slurry is subjected to vacuum extrusion, and then dried at 40℃ for 36h, and then dried at 130℃ for 4h, and then heated to 500℃ at a heating rate of 8℃ / min and kept for 4h, to perform calcination treatment, to obtain the vanadium-based honeycomb ultra-low-temperature denitration catalyst.

[0063] Example 3

[0064] The embodiment provides a preparation method of a vanadium-based honeycomb ultra-low-temperature denitration catalyst, which is different from the method in Example 1 only in that the mass ratio of the ammonium metavanadate, ammonium heptamolybdate, nano-titanium dioxide and expanded graphite in step (1) is adjusted to 1:1:97.5:0.5, and other preparation steps and parameter conditions are the same as those in Example 1.

[0065] Example 4

[0066] The embodiment provides a preparation method of a vanadium-based honeycomb ultra-low-temperature denitration catalyst, which is different from the method in Example 1 only in that the mass ratio of the ammonium metavanadate, ammonium heptamolybdate, nano-titanium dioxide and expanded graphite in step (1) is adjusted to 1:1:97.5:0.5, and other preparation steps and parameter conditions are the same as those in Example 1.

[0067] Example 5

[0068] The embodiment provides a preparation method of a vanadium-based honeycomb ultra-low-temperature denitration catalyst, which is different from the method in Example 1 only in that the mass ratio of the catalyst particles, basic cerium carbonate, glass fiber, starch, stearic acid and glycerol in step (3) is adjusted to 95.5:0.5:1:1:1:1, and other preparation steps and parameter conditions are the same as those in Example 1.

[0069] Example 6

[0070] The embodiment provides a preparation method of a vanadium-based honeycomb ultra-low-temperature denitration catalyst, which is different from the method in Example 1 only in that the mass ratio of the catalyst particles, basic cerium carbonate, glass fiber, starch, stearic acid and glycerol in step (3) is adjusted to 95.5:0.5:1:1:1:1, and other preparation steps and parameter conditions are the same as those in Example 1.

[0071] Comparative Example 1

[0072] The comparative example provides a preparation method of a vanadium-based honeycomb ultra-low-temperature denitration catalyst, which is different from the method in Example 1 only in that the hydrophobic agent is omitted in step (1) and is replaced by an equal amount of nano-titanium dioxide, and other preparation steps and parameter conditions are the same as those in Example 1.

[0073] Comparative Example 2

[0074] The present comparative example provides a preparation method of a vanadium-based honeycomb ultra-low temperature denitration catalyst, which is different from example 1 only in that the addition of the rare earth modifier in step (3) is omitted, and the same mass thereof is replaced by catalyst particles, and other preparation steps and parameter conditions are the same as those of example 1.

[0075] Comparative Example 3

[0076] The present comparative example provides a preparation method of a vanadium-based honeycomb ultra-low temperature denitration catalyst, which is different from example 1 only in that the cerium carbonate in step (3) is replaced by the same mass of block copolymer template agent P123, and other preparation steps and parameter conditions are the same as those of example 1.

[0077] Comparative Example 4

[0078] The present comparative example provides a preparation method of a vanadium-based honeycomb ultra-low temperature denitration catalyst, which is different from example 1 only in that the cerium carbonate in step (3) is replaced by the same mass of cerium nitrate, and other preparation steps and parameter conditions are the same as those of example 1.

[0079] Comparative Example 5

[0080] The present comparative example provides a preparation method of a vanadium-based honeycomb ultra-low temperature denitration catalyst, which is different from example 1 only in that the cerium carbonate in step (3) is replaced by the same mass of yttrium carbonate, and other preparation steps and parameter conditions are the same as those of example 1.

[0081] Performance test

[0082] The denitration performance of the vanadium-based honeycomb ultra-low temperature denitration catalysts prepared in examples 1-6 and comparative examples 1-5 was tested under test conditions 1-3, respectively; the test results are shown in Tables 1 and Figure 2 .

[0083] Among them, test condition 1 is: reaction temperature 100-160℃, gas condition is: 1000ppm of NH3+1000ppm of NO+5v.%of O2, N2balance, pressure is normal pressure, space velocity is 5000mL·mg -1 ·h -1 The reaction activity of the catalyst was determined by the conversion rate of NO, and the reaction product was analyzed by a Gasmet flue gas analyzer;

[0084] Test condition 2 is: reaction temperature 100-160℃, gas condition is: 1000ppm of NH3+1000ppm of NO+15v.%of H2O+5v.%of O2, N2balance, pressure is normal pressure, space velocity is 5000mL·mg-1 ·h -1 The reaction activity of the catalyst was determined by the conversion rate of NO, and the reaction product was analyzed by a Gasmet flue gas analyzer;

[0085] Test condition 3: reaction temperature 100-160℃, gas condition: 1000ppm of NH3+1000ppm of NO+10v.% of SO2+5v.% of O2, N2 balance, pressure: normal pressure, space velocity: 5000mL·mg -1 ·h -1 The reaction activity of the catalyst was determined by the conversion rate of NO, and the reaction product was analyzed by a Gasmet flue gas analyzer.

[0086] Table 1

[0087]

[0088] *Test temperature: 160℃.

[0089] Performance analysis

[0090] (1) It can be seen from Examples 1-2 that the preparation method of the application adds a hydrophobic agent and a rare earth modifier, so that the prepared catalyst has good water and sulfur resistance denitration performance, and can still maintain a denitration efficiency of more than 90% in flue gas containing water and sulfur;

[0091] (2) It can be seen from Examples 1 and Examples 3-4 that adjusting the mass of the hydrophobic agent helps to improve the water and sulfur resistance denitration performance of the catalyst, thereby improving the denitration efficiency of flue gas containing water and sulfur;

[0092] (3) It can be seen from Examples 1 and Examples 5-6 that adjusting the mass of the rare earth modifier helps to improve the water and sulfur resistance denitration performance of the catalyst, thereby improving the denitration efficiency of flue gas containing water and sulfur;

[0093] (4) It can be seen from Examples 1 and Comparative Examples 1-2 that whether the addition of the hydrophobic agent is omitted in Comparative Example 1 or the addition of the rare earth modifier is omitted in Comparative Example 2, the water and sulfur resistance denitration performance of the catalyst will be reduced, thereby reducing the denitration efficiency of flue gas containing water and sulfur; there is a synergistic effect between the added hydrophobic agent and the rare earth modifier, which can further improve the water and sulfur resistance denitration performance of the catalyst;

[0094] (5) It can be seen from Examples 1 and Comparative Examples 3-5 that the addition of the block copolymer template agent P123 can also form a vanadium-based honeycomb catalyst with high porosity, but it cannot improve the sulfur resistance of the catalyst, thereby reducing the denitration efficiency of flue gas containing water and sulfur;

[0095] In the comparative example 4, cerium nitrate is added as a rare earth modifier, which cannot form a vanadium-based honeycomb catalyst with high porosity, thereby reducing the denitration efficiency for the water-containing and sulfur-containing flue gas; in the comparative example 5, basic yttrium carbonate is added as a rare earth modifier, so that the prepared catalyst does not have sulfur resistance, thereby reducing the denitration efficiency for the water-containing and sulfur-containing flue gas.

[0096] In summary, the present application provides a vanadium-based honeycomb ultra-low temperature denitration catalyst, a preparation method and application thereof. By adding a hydrophobic agent, a hydrophobic layer is formed on the surface of the catalyst, which can reduce the contact between water molecules and active sites, thereby improving the denitration efficiency of the catalyst in the water-containing and sulfur-containing flue gas environment. By adding a rare earth modifier, a vanadium-based honeycomb catalyst with high porosity can be prepared. The oxides produced by high-temperature decomposition of the rare earth modifier after calcination can also make the catalyst have sulfur resistance. The catalyst of the present application can still maintain high denitration efficiency (≥90%) below 160℃, realizing ultra-low temperature denitration and meeting the low-temperature flue gas treatment demand. At the same time, the preparation method is simple and suitable for industrial large-scale production.

[0097] The applicant declares that the above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by any person skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for preparing a vanadium-based honeycomb ultra-low temperature denitration catalyst, characterized in that, The preparation method includes: (1) After mixing vanadium salt, molybdenum salt, nano titanium dioxide and hydrophobic agent, add organic acid and knead to obtain the first mud material; (2) The first mud material is subjected to a first molding process, drying and calcination to obtain catalyst particles; (3) The catalyst particles are crushed and then mixed and kneaded with rare earth modifier and additives. The resulting second mud is subjected to a second molding process, drying and calcination to obtain the vanadium-based honeycomb ultra-low temperature denitrification catalyst.

2. The preparation method according to claim 1, characterized in that, The vanadium salt mentioned in step (1) includes ammonium metavanadate; Preferably, the molybdenum salt comprises ammonium heptamolybdate; Preferably, the hydrophobic agent comprises any one or a combination of at least two of expanded graphite, siloxane, or N-methylsilane; Preferably, the organic acid includes any one or a combination of at least two of oxalic acid, glacial acetic acid, or citric acid.

3. The preparation method according to claim 1 or 2, characterized in that, The mass ratio of the vanadium salt, molybdenum salt, nano titanium dioxide and hydrophobic agent is (1-5):(1-5):(85-97):(1-5).

4. The preparation method according to any one of claims 1-3, characterized in that, The drying temperature in step (2) is 100–110°C; the drying time is 10–12 hours. Preferably, the roasting temperature is 450–500°C; the roasting time is 4–6 hours. Preferably, the heating rate of the calcination is 6-8°C / min.

5. The preparation method according to any one of claims 1-4, characterized in that, The particle size of the catalyst particles after crushing in step (3) is ≤325 mesh; Preferably, the rare earth modifier includes basic cerium carbonate.

6. The preparation method according to any one of claims 1-5, characterized in that, The additives mentioned in step (3) include molding aids, binders, lubricants, and humectants; Preferably, the molding aid includes any one of glass fiber, pulp fiber, or lactic acid; Preferably, the binder comprises any one or a combination of at least two of starch, methylcellulose, hydroxypropyl methylcellulose, hydroxyethylcellulose, or carboxymethylcellulose; Preferably, the lubricant comprises stearic acid; Preferably, the moisturizer includes glycerin; Preferably, the mass ratio of the catalyst particles, rare earth modifier, molding aid, binder, lubricant and humectant is (87-95):(1-5):(1-2):(1-2):(1-2):(1-2).

7. The preparation method according to any one of claims 1-6, characterized in that, The drying process in step (3) includes a first drying and a second drying. Preferably, the temperature of the first drying is 40–60°C; the drying time is 24–36 hours. Preferably, the temperature of the second drying is 120-130°C; and the drying time is 4-6 hours.

8. The preparation method according to any one of claims 1-7, characterized in that, The calcination temperature in step (3) is 400–500°C; the calcination time is 4–6 hours. Preferably, the heating rate of the calcination is 5-8°C / min.

9. A vanadium-based honeycomb ultra-low temperature denitration catalyst, characterized in that, The vanadium-based honeycomb ultra-low temperature denitrification catalyst is prepared by the preparation method described in any one of claims 1-8.

10. The application of the vanadium-based honeycomb ultra-low temperature denitrification catalyst as described in claim 9 in the coking, power generation, steel, glass, ceramics and cement industries.

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