Modified attapulgite honeycomb denitration catalyst and preparation method thereof

Abstract

The invention provides a modified attapulgite honeycomb denitration catalyst and a preparation method thereof, and relates to the technical field of air pollution control and environment-friendly materials. The treated attapulgite and the treated furfural residues are compounded, an acid-ethanol solution in which metal salt and a modifier are dissolved and mixed powder are subjected to ball milling and drying, surface functional groups of the attapulgite are increased, dispersion of active components on the surface of the attapulgite is promoted, the strong interaction between the attapulgite and the active components is enhanced, and the interfacial effect is improved. The attapulgite honeycomb denitration catalyst is obtained by mixing, aging, molding, drying and roasting the graded attapulgite subjected to ball milling, a molding aid and a binder. According to the invention, the doping proportion of the attapulgite can reach more than 80% under the condition of keeping relatively high denitration efficiency, the cost is greatly reduced, and the mechanical strength is superior to the national standard.

Description

Technical Field

[0001] This invention relates to the fields of air pollution control and environmental protection materials technology, and in particular to a low-cost modified attapulgite honeycomb denitrification catalyst based on interface effects and its preparation method. Background Technology

[0002] Stationary source flue gas denitrification often employs Selective Catalytic Reduction (SCR), a process in which ammonia, a reducing agent, reacts with nitrogen oxides in the flue gas under the action of a catalyst to selectively generate nitrogen and water. The catalyst, as the core of this technology, typically consists mainly of vanadium (active component), tungsten and molybdenum (auxiliaries), and titanium dioxide (support). Titanium dioxide, as the main component of the catalyst, accounts for over 80%, significantly contributing to the cost of catalyst raw materials. To reduce costs, many companies add spent catalyst powder during production, resulting in inconsistent product quality and severely impacting catalyst lifespan and the market ecosystem. To seek more reliable cost reduction methods, many researchers have attempted to incorporate natural minerals into the catalyst. Attapulgite, a layered chain aluminosilicate, possesses advantages such as large specific surface area, strong adsorption, and resistance to sintering, making it a potential alternative to titanium dioxide as a support.

[0003] Patent CN101862648A discloses an SCR denitration catalyst with added attapulgite and its preparation method. This method involves purifying attapulgite to over 60% and then doping it into a conventional denitration catalyst at a doping ratio of 15%. The resulting catalyst undergoes a 32,000-hour cooling cycle. -1 It achieves a denitrification efficiency of over 81%. Although this method successfully uses attapulgite as a substitute, the proportion of attapulgite used is relatively low, and the cost reduction still needs to be improved.

[0004] Patent CN117696044B discloses a doped attapulgite rare earth SCR catalyst and its preparation method. This method involves preparing a slurry from attapulgite, sodium hexametaphosphate, and rare earth salts, supplemented with a sol formed from alumina, silicon dioxide, ethylene glycol, and water, and then coating it onto a honeycomb ceramic carrier using negative pressure filtration. This technology can significantly reduce the amount of active components and titanium dioxide used, but it carries the risk of coating detachment. Therefore, low-cost, long-life denitrification catalysts are a key focus for future research and development. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides a modified attapulgite honeycomb denitration catalyst and its preparation method. The attapulgite doping ratio can reach over 80% with high denitration efficiency, significantly reducing costs and exhibiting mechanical strength superior to national standards. One of the objectives of this invention is to provide a method for preparing a modified attapulgite honeycomb denitrification catalyst.

[0006] The second objective of this invention is to provide a modified attapulgite honeycomb denitrification catalyst prepared by this method.

[0007] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: In a first aspect, the present invention provides a method for preparing a modified attapulgite honeycomb denitration catalyst, comprising the following steps: (a) Dissolve nitrogen-containing organic base in deionized water, add furfural residue after complete dissolution and mix evenly, then dry by microwave to obtain product one; (b) Dissolve the surfactant, coupling agent and metal salt in deionized water. After complete dissolution, add attapulgite and mix evenly. Then sonicate and microwave dry to obtain product two. (c) The mixed powder obtained by mixing product one and product two is placed in a planetary ball mill; the acid, modifier and anhydrous ethanol are mixed evenly, and then the active component metal salt is added. After complete dissolution, the solution is atomized and sprayed into the planetary ball mill through an atomizing nozzle for mixing and ball milling; after ball milling, it is dried and then calcined under a nitrogen atmosphere to obtain the modified attapulgite powder. (d) The modified attapulgite powder was ground into 400 mesh, 800 mesh, 1500 mesh and 3000 mesh by an ultrafine grinding mill to obtain attapulgite powder of 400 mesh, 800 mesh, 1500 mesh and 3000 mesh respectively. (e) The molding aid, binder and attapulgite powder of 400 mesh, 800 mesh, 1500 mesh and 3000 mesh are mixed in a mixer. The resulting mud is left to stand in the dark and aged. It is then extruded and shaped by a honeycomb extruder, dried and calcined to obtain the modified attapulgite honeycomb denitrification catalyst.

[0008] The following is a detailed explanation: In some embodiments, in step (a), the nitrogen-containing organic base is one or more of tetramethylethylenediamine, triethylamine, ephedrine, and melamine; In some embodiments, in step (a), the weight ratio of nitrogen-containing organic base, furfural residue, and deionized water is 0.01~0.1:0.5~1:1; In some implementations, in step (a), the microwave drying power is 20-40 kW and the time is 4-8 hours.

[0009] The furfural residue used in this step is not only inexpensive but also porous. By treating the furfural residue with nitrogen-containing organic bases, the non-metallic reaction sites of the activated carbon can be increased, thereby improving the low-temperature catalytic performance.

[0010] In some embodiments, in step (b), the surfactant is one or more of hexadecyltrimethylammonium bromide, P123, and polyethylene glycol; the coupling agent is one or more of SCA-1113, NDZ-101, and KH-560; and the metal salt is one or more of ferric nitrate, cobalt nitrate, cerium nitrate, chromium nitrate, zirconium nitrate, and titanium sulfate. Attapulgite refers to acid-washed and activated attapulgite. You can purchase commercially available, pre-acid-washed attapulgite directly, or you can acid-wash commercially available attapulgite before use. The grade of the acid-washed and activated attapulgite should be above 30%.

[0011] In some embodiments, in step (b), the mass ratio of surfactant, coupling agent, metal salt, attapulgite and deionized water is 0.01~0.05:0.005~0.02:0.05~0.2:0.5~1:1.

[0012] In some embodiments, in step (b), the ultrasonic temperature is 40~80℃, the ultrasonic frequency is 20~60kHz, and the ultrasonic time is 1~4 hours; the microwave drying power is 20~40kW, and the time is 8~12 hours.

[0013] This step involves treating attapulgite by adding surfactants and coupling agents, which improves the pore structure of attapulgite, optimizes the bonding ability between metal oxides and attapulgite, and enhances the intrinsic redox properties of attapulgite through the addition of metal salts.

[0014] In some embodiments, in step (c), the mass ratio of product one to product two is 0.01 to 0.1:1; In some embodiments, in step (c), the acid is one of oxalic acid, tartaric acid, citric acid, or glycolic acid; the modifier is one of sodium dodecyl sulfate, polyvinylpyrrolidone, or polyethyleneimine; and the active component metal salt is one or more of ammonium metavanadate, ammonium paratungstate, ammonium heptamolybdate, titanium sulfate, ferric nitrate, cobalt nitrate, and cerium nitrate.

[0015] In some embodiments, in step (c), the mass ratio of acid, modifier, anhydrous ethanol and mixed powder is 0.02~0.06:0.01~0.05:0.6~0.8:1; and the mass ratio of active component metal salt to mixed powder is 0.05~0.2:1.

[0016] In some embodiments, in step (c), the ball milling speed is 300~700 r / min and the ball milling time is 4~8 hours; In some embodiments, in step (c), drying is performed by increasing the temperature to 120°C at a rate of 5°C / min and drying until the moisture content of the powder is less than 5%. In some embodiments, in step (c), the calcination temperature is 400~600℃ and the calcination time is 2~4 hours.

[0017] By combining acid-activated attapulgite with modified furfural slag and metal salts, the specific surface area utilization rate of attapulgite was improved, the pore structure distribution was optimized, and the number of carrier reaction vacancies and active sites was increased, while further enhancing its compatibility with active components. Ball milling and drying of the mixed powder with an acid-ethanol solution containing the active component metal salt and modifier increased the surface functional groups of attapulgite, promoted the dispersion of active components on the attapulgite surface, strengthened the strong interaction between attapulgite and active components, and increased the interfacial effect.

[0018] In some embodiments, in step (e), the molding aid is one or more of lactic acid, polyacrylic acid, and polyethylene glycol; and the binder is one or more of carboxymethyl cellulose, polyvinyl alcohol, and polyethylene oxide.

[0019] In some embodiments, in step (e), the mass ratio of 400 mesh, 800 mesh, 1500 mesh, and 3000 mesh attapulgite powder is 0.05~0.2:0.1~0.3:0.15~0.3:0.1~0.7; the mass ratio of molding aid to total attapulgite powder is 0.01~0.05:1; and the mass ratio of binder to total attapulgite powder is 0.01~0.1:1.

[0020] In some embodiments, in step (e), the plant is left to stand in the dark for 12 to 24 hours to age; the drying temperature is 40 to 80°C and the drying time is 4 to 6 days; the calcination temperature is 450 to 600°C and the calcination time is 2 to 6 hours.

[0021] The ball-milled attapulgite gradation, along with molding aids and binders, is mixed, aged, molded, dried, and calcined to obtain a modified attapulgite honeycomb denitrification catalyst.

[0022] By adding attapulgite in a graded manner during the molding process, the molding cycle of the honeycomb denitrification catalyst can be shortened while ensuring high mechanical strength; at the same time, the use of various additives during the molding process can be reduced, thereby lowering the raw material cost of the catalyst.

[0023] Secondly, the present invention provides a modified attapulgite honeycomb denitrification catalyst, which is prepared by the above preparation method.

[0024] Beneficial effects: 1. This invention improves the specific surface area, reaction sites, and compatibility of active components of attapulgite through modification, specifically by: ① After being compounded and modified with metal salt, product 2, through the regulation of ultrasonic cavitation effect and non-thermal effect of microwave field, has greatly improved the specific surface area utilization rate, pore structure distribution, and compatibility of reactive sites and active components of attapulgite; after being further compounded with product 1, the specific surface area and reactive vacancies are optimized again. ② The alcohol solution containing acid, metal salt and modifier is atomized and sprayed in, and ball-milled with product one and product two. This can increase the surface functional groups of attapulgite, promote the dispersion of active components on the surface of attapulgite, strengthen the strong interaction between attapulgite and active components, and enhance the interfacial effect.

[0025] 2. The modified attapulgite honeycomb denitrification catalyst of the present invention has a titanium dioxide substitution rate of over 80%. Compared with traditional vanadium-titanium denitrification catalysts, it maintains good denitrification performance while further reducing costs through graded molding and improving the mechanical strength of the catalyst after molding. It can replace the current denitrification catalyst route and process that uses waste materials for cost reduction.

[0026] The present invention has been described in detail above; however, the above embodiments are merely illustrative in nature and are not intended to limit the invention. Furthermore, this document is not limited to the foregoing prior art or the invention itself, or to any theory described in the following embodiments. Detailed Implementation

[0027] The present invention will be further described below with reference to the embodiments. It should be noted that the following embodiments are provided for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0028] Unless otherwise specified, the raw materials, reagents, and methods used in the embodiments are all conventional raw materials, reagents, and methods in the art.

[0029] Example 1 1. Dissolve 0.1 kg of tetramethylethylenediamine in 10 liters of deionized water. After complete dissolution, add 5 kg of furfural residue and stir for 2 hours. Dry the material under microwave power of 20 kW for 8 hours to obtain product one. 2. Dissolve 0.1 kg cetyltrimethylammonium bromide, 50 g SCA-1113 and 0.5 kg ferric nitrate in 10 liters of deionized water. After complete dissolution, add 5 kg of attapulgite that has been activated by acid washing with 5% hydrochloric acid and mix evenly. Sonicate at 40°C for 4 hours, and then dry for 12 hours under microwave power of 20 kW to obtain product two. 3. Place 0.05 kg of product one and 3.95 kg of product two mixed powder in a planetary ball mill; mix 0.1 kg of oxalic acid, 0.05 kg of sodium dodecyl sulfate and 3 kg of anhydrous ethanol evenly, then add 0.15 kg of ammonium metavanadate, 0.05 kg of ammonium paratungstate and 0.05 kg of ammonium heptamolybdate. After complete dissolution, the solution is atomized and sprayed into the planetary ball mill through an atomizing nozzle, and ball milled at 700 r / min for 4 hours; after ball milling, raise the temperature to 120℃ at 5℃ / min, dry until the powder moisture content is less than 5%, and then calcine at 400℃ for 2 hours under a nitrogen atmosphere to obtain the modified attapulgite powder; 4. Grind the modified attapulgite powder obtained in step 3 into 400 mesh, 800 mesh, 1500 mesh and 3000 mesh using an ultrafine grinding mill for later use. 5. Mix 0.05 kg of lactic acid, 0.05 kg of carboxymethyl cellulose, and 1 kg of 400 mesh, 1 kg of 800 mesh, 1.5 kg of 1500 mesh, and 1.5 kg of 3000 mesh attapulgite powder in a mixer. After the resulting mud is allowed to stand in the dark for 24 hours to age, it is extruded into shape using a honeycomb extruder. The shaped honeycomb denitrification catalyst is dried at 40℃ for 6 days and then calcined at 450℃ for 6 hours to obtain the modified attapulgite honeycomb denitrification catalyst.

[0030] Example 2 1. Dissolve 0.2 kg of triethylamine in 10 liters of deionized water. After complete dissolution, add 6 kg of furfural residue and stir for 2 hours. Dry the material under microwave power of 25 kW for 7 hours to obtain product one. 2. Dissolve 0.2 kg P123, 100 g NDZ-101 and 0.5 kg cobalt nitrate in 10 liters of deionized water. After complete dissolution, add 6 kg of attapulgite that has been activated by acid washing with 5% hydrochloric acid and mix evenly. Sonicate at 50°C for 3 hours, and then dry under microwave power of 25 kW for 10 hours to obtain product two. 3. Place 0.1 kg of product one and 4.9 kg of product two mixed powder in a planetary ball mill; mix 0.15 kg of tartaric acid, 0.1 kg of polyvinylpyrrolidone and 3.5 kg of anhydrous ethanol evenly, then add 0.2 kg of ammonium metavanadate, 0.05 kg of ammonium paratungstate and 0.05 kg of ferric nitrate. After complete dissolution, the solution is atomized and sprayed into the planetary ball mill through an atomizing nozzle, and ball milled at 600 r / min for 5 hours; after ball milling, raise the temperature to 120℃ at 5℃ / min, dry until the powder moisture content is less than 5%, and then calcine at 400℃ for 3 hours under a nitrogen atmosphere to obtain the modified attapulgite powder; 4. Grind the modified attapulgite powder obtained in step 3 into 400 mesh, 800 mesh, 1500 mesh and 3000 mesh using an ultrafine grinding mill for later use. 5. Mix 0.1 kg of polyacrylic acid, 0.1 kg of polyvinyl alcohol, and 0.5 kg of 400 mesh, 1 kg of 800 mesh, 2 kg of 1500 mesh, and 1.5 kg of 3000 mesh attapulgite powder in a mixer. After the resulting mud is allowed to stand in the dark for 20 hours to age, it is extruded into shape using a honeycomb extruder. The shaped honeycomb denitrification catalyst is dried at 50°C for 5 days and then calcined at 500°C for 5 hours to obtain the modified attapulgite honeycomb denitrification catalyst.

[0031] Example 3 1. Dissolve 0.3 kg of ephedrine in 10 liters of deionized water. After complete dissolution, add 7 kg of furfural residue and stir for 2 hours. Dry the material under microwave power of 30 kW for 6 hours to obtain product one. 2. Dissolve 0.3 kg of polyethylene glycol, 150 g of KH-560 and 1 kg of cerium nitrate in 10 liters of deionized water. After complete dissolution, add 8 kg of attapulgite that has been activated by acid washing with 5% hydrochloric acid and mix evenly. Sonicate at 60°C for 2 hours, and then dry for 9 hours under microwave power of 30 kW to obtain product two. 3. Place 0.25 kg of product one and 4.75 kg of product two mixed powder in a planetary ball mill; mix 0.2 kg of citric acid, 0.15 kg of polyethyleneimine and 4 kg of anhydrous ethanol evenly, then add 0.1 kg of ammonium metavanadate, 0.05 kg of ammonium paratungstate, 0.15 kg of titanium sulfate and 0.05 kg of cerium nitrate. After complete dissolution, the solution is atomized and sprayed into the planetary ball mill through an atomizing nozzle, and ball milled at 500 r / min for 6 hours; after ball milling, raise the temperature to 120℃ at 5℃ / min, dry until the powder moisture content is less than 5%, and then calcine at 400℃ for 4 hours under a nitrogen atmosphere to obtain the modified attapulgite powder; 4. Grind the modified attapulgite powder obtained in step 3 into 400 mesh, 800 mesh, 1500 mesh and 3000 mesh using an ultrafine grinding mill for later use. 5. Mix 0.15 kg of polyethylene glycol, 0.06 kg of polyethylene oxide, and 1 kg of 400 mesh, 0.5 kg of 800 mesh, 1.5 kg of 1500 mesh, and 2 kg of 3000 mesh attapulgite powder in a mixer. After the resulting mud is allowed to stand in the dark for 18 hours to age, it is extruded into shape using a honeycomb extruder. The shaped honeycomb denitrification catalyst is dried at 60°C for 5 days and then calcined at 550°C for 4 hours to obtain the modified attapulgite honeycomb denitrification catalyst.

[0032] Example 4 1. Dissolve 0.5 kg of melamine in 10 liters of deionized water. After complete dissolution, add 8 kg of furfural residue and stir for 2 hours. Dry the material under microwave power of 40 kW for 4 hours to obtain product one. 2. Dissolve 0.5 kg P123, 200 g SCA-1113 and 0.5 kg zirconium nitrate in 10 liters of deionized water. After complete dissolution, add 10 kg of attapulgite that has been activated by acid washing with 5% hydrochloric acid and mix evenly. Sonicate at 80°C for 1 hour, and then dry under microwave power of 35 kW for 8 hours to obtain product two. 3. Place 0.3 kg of product one and 4.7 kg of product two mixed powder in a planetary ball mill; mix 0.25 kg of glycolic acid, 0.2 kg of polyvinylpyrrolidone and 4 kg of anhydrous ethanol evenly, then add 0.2 kg of ammonium metavanadate, 0.1 kg of ammonium paratungstate, 0.05 kg of cobalt nitrate and 0.05 kg of cerium nitrate. After complete dissolution, the solution is atomized and sprayed into the planetary ball mill through an atomizing nozzle, and ball milled at 300 r / min for 8 hours; after ball milling, heat to 120℃ at 5℃ / min, dry until the powder moisture content is less than 5%, and then calcine at 400℃ for 4 hours under a nitrogen atmosphere to obtain the modified attapulgite powder; 4. Grind the modified attapulgite powder obtained in step 3 into 400 mesh, 800 mesh, 1500 mesh and 3000 mesh using an ultrafine grinding mill for later use. 5. Mix 0.1 kg of lactic acid, 0.15 kg of polyethylene oxide, and 0.5 kg of 400 mesh, 0.5 kg of 800 mesh, 1.5 kg of 1500 mesh, and 2.5 kg of 3000 mesh attapulgite powder in a mixer. After the resulting mud is allowed to stand in the dark for 12 hours to age, it is extruded into shape using a honeycomb extruder. The shaped honeycomb denitrification catalyst is dried at 80℃ for 4 days and then calcined at 600℃ for 3 hours to obtain the modified attapulgite honeycomb denitrification catalyst.

[0033] Comparative Example 1 In Comparative Example 1, step 1 of Example 4 is deleted, while other processes remain unchanged. The specific steps are as follows: 1. Dissolve 0.5 kg P123, 200 g SCA-1113 and 0.5 kg zirconium nitrate in 10 liters of deionized water. After complete dissolution, add 10 kg of acid-washed and activated attapulgite and mix evenly. Sonicate at 80°C for 1 hour, and then microwave dry for 8 hours at a microwave power of 35 kW to obtain product 2. 2. Place 5 kg of product 2 in a planetary ball mill; mix 0.25 kg of glycolic acid, 0.2 kg of polyvinylpyrrolidone and 4 kg of anhydrous ethanol evenly, then add 0.2 kg of ammonium metavanadate, 0.1 kg of ammonium paratungstate, 0.05 kg of cobalt nitrate and 0.05 kg of cerium nitrate. After complete dissolution, the solution is atomized and sprayed into the planetary ball mill through an atomizing nozzle, and ball milled at 300 r / min for 8 hours; after ball milling, the temperature is increased to 120℃ at 5℃ / min, and dried until the moisture content of the powder is less than 5%. Then, calcine at 400℃ for 4 hours under a nitrogen atmosphere to obtain the modified attapulgite powder. 3. Grind the modified attapulgite powder obtained in step 2 into 400 mesh, 800 mesh, 1500 mesh and 3000 mesh using an ultrafine grinding mill for later use. 4. Mix 0.1 kg of lactic acid, 0.15 kg of polyethylene oxide, and 0.5 kg of 400 mesh, 0.5 kg of 800 mesh, 1.5 kg of 1500 mesh, and 2.5 kg of 3000 mesh attapulgite powder in a mixer. After the resulting mud is allowed to stand in the dark for 12 hours to age, it is extruded into shape using a honeycomb extruder. The shaped honeycomb denitrification catalyst is dried at 80°C for 4 days and then calcined at 600°C for 3 hours to obtain the modified attapulgite honeycomb denitrification catalyst.

[0034] Comparative Example 2 In Comparative Example 2, the surfactant and coupling agent steps in step 2 of Example 4 are removed, while other processes remain unchanged. The specific steps are as follows: 1. Dissolve 0.5 kg of melamine in 10 liters of deionized water. After complete dissolution, add 8 kg of furfural residue and stir for 2 hours. Dry the material under microwave power of 40 kW for 4 hours to obtain product one. 2. Dissolve 0.5 kg of zirconium nitrate in 10 liters of deionized water. After complete dissolution, add 10 kg of acid-washed and activated attapulgite and mix evenly. Sonicate at 80°C for 1 hour, and then dry for 8 hours under microwave power of 35 kW to obtain product two. 3. Place 0.3 kg of product one and 4.7 kg of product two mixed powder in a planetary ball mill; mix 0.25 kg of glycolic acid, 0.2 kg of polyvinylpyrrolidone and 4 kg of anhydrous ethanol evenly, then add 0.2 kg of ammonium metavanadate, 0.1 kg of ammonium paratungstate, 0.05 kg of cobalt nitrate and 0.05 kg of cerium nitrate. After complete dissolution, the solution is atomized and sprayed into the planetary ball mill through an atomizing nozzle, and ball milled at 300 r / min for 8 hours; after ball milling, heat to 120℃ at 5℃ / min, dry until the powder moisture content is less than 5%, and then calcine at 400℃ for 4 hours under a nitrogen atmosphere to obtain the modified attapulgite powder; 4. Grind the modified attapulgite powder obtained in step 3 into 400 mesh, 800 mesh, 1500 mesh and 3000 mesh using an ultrafine grinding mill for later use. 5. Mix 0.1 kg of lactic acid, 0.15 kg of polyethylene oxide, and 0.5 kg of 400 mesh, 0.5 kg of 800 mesh, 1.5 kg of 1500 mesh, and 2.5 kg of 3000 mesh attapulgite powder in a mixer. After the resulting mud is allowed to stand in the dark for 12 hours to age, it is extruded into shape using a honeycomb extruder. The shaped honeycomb denitrification catalyst is dried at 80℃ for 4 days and then calcined at 600℃ for 3 hours to obtain the modified attapulgite honeycomb denitrification catalyst.

[0035] Comparative Example 3 In Comparative Example 3, the step of adding acid and modifier in step 3 of Example 4 is deleted, while other processes remain unchanged. The specific steps are as follows: 1. Dissolve 0.5 kg of melamine in 10 liters of deionized water. After complete dissolution, add 8 kg of furfural residue and stir for 2 hours. Dry the material under microwave power of 40 kW for 4 hours to obtain product one. 2. Dissolve 0.5 kg P123, 200 g SCA-1113 and 0.5 kg zirconium nitrate in 10 liters of deionized water. After complete dissolution, add 10 kg of attapulgite that has been activated by acid washing with 5% hydrochloric acid and mix evenly. Sonicate at 80°C for 1 hour, and then dry under microwave power of 35 kW for 8 hours to obtain product two. 3. Place the mixed powder of 0.3 kg of product one and 4.7 kg of product two into a planetary ball mill; add 0.2 kg of ammonium metavanadate, 0.1 kg of ammonium paratungstate, 0.05 kg of cobalt nitrate and 0.05 kg of cerium nitrate to 4 kg of anhydrous ethanol. After complete dissolution, the solution is atomized and sprayed into the planetary ball mill through an atomizing nozzle, and ball milled at 300 r / min for 8 hours; after ball milling, the temperature is increased to 120℃ at 5℃ / min, and dried until the moisture content of the powder is less than 5%. Then, calcine at 400℃ for 4 hours under a nitrogen atmosphere to obtain the modified attapulgite powder. 4. Grind the modified attapulgite powder obtained in step 3 into 400 mesh, 800 mesh, 1500 mesh and 3000 mesh using an ultrafine grinding mill for later use. 5. Mix 0.1 kg of lactic acid, 0.15 kg of polyethylene oxide, and 0.5 kg of 400 mesh, 0.5 kg of 800 mesh, 1.5 kg of 1500 mesh, and 2.5 kg of 3000 mesh attapulgite powder in a mixer. After the resulting mud is allowed to stand in the dark for 12 hours to age, it is extruded into shape using a honeycomb extruder. The shaped honeycomb denitrification catalyst is dried at 80℃ for 4 days and then calcined at 600℃ for 3 hours to obtain the modified attapulgite honeycomb denitrification catalyst.

[0036] Comparative Example 4 In Comparative Example 4, the addition of attapulgite with different mesh sizes in step 4 of Example 4 was changed to only 400 mesh, while other processes remained unchanged. The specific steps are as follows: 1. Dissolve 0.5 kg of melamine in 10 liters of deionized water. After complete dissolution, add 8 kg of furfural residue and stir for 2 hours. Dry the material under microwave power of 40 kW for 4 hours to obtain product one. 2. Dissolve 0.5 kg P123, 200 g SCA-1113 and 0.5 kg zirconium nitrate in 10 liters of deionized water. After complete dissolution, add 10 kg of attapulgite that has been activated by acid washing with 5% hydrochloric acid and mix evenly. Sonicate at 80°C for 1 hour, and then dry under microwave power of 35 kW for 8 hours to obtain product two. 3. Place 0.3 kg of product one and 4.7 kg of product two mixed powder in a planetary ball mill; mix 0.25 kg of glycolic acid, 0.2 kg of polyvinylpyrrolidone and 4 kg of anhydrous ethanol evenly, then add 0.2 kg of ammonium metavanadate, 0.1 kg of ammonium paratungstate, 0.05 kg of cobalt nitrate and 0.05 kg of cerium nitrate. After complete dissolution, the solution is atomized and sprayed into the planetary ball mill through an atomizing nozzle, and ball milled at 300 r / min for 8 hours; after ball milling, heat to 120℃ at 5℃ / min, dry until the powder moisture content is less than 5%, and then calcine at 400℃ for 4 hours under a nitrogen atmosphere to obtain the modified attapulgite powder; 4. Grind the modified attapulgite powder obtained in step 3 into 400 mesh using an ultrafine grinding mill for later use. 5. Mix 0.04 kg of lactic acid, 0.02 kg of polyethylene oxide and 5 kg of 400 mesh attapulgite powder in a mixer. After the resulting mud is allowed to stand in the dark for 12 hours to age, it is extruded into shape through a honeycomb extruder. The shaped honeycomb denitrification catalyst is dried at 80℃ for 4 days and then calcined at 600℃ for 3 hours to obtain the modified attapulgite honeycomb denitrification catalyst.

[0037] Comparative Example 5 In Comparative Example 4, the mixed powder in step 3 of Example 4 was placed in a mixer instead of a planetary ball mill, while other processes remained unchanged. The specific steps are as follows: 1. Dissolve 0.5 kg of melamine in 10 liters of deionized water. After complete dissolution, add 8 kg of furfural residue and stir for 2 hours. Dry the material under microwave power of 40 kW for 4 hours to obtain product one. 2. Dissolve 0.5 kg P123, 200 g SCA-1113 and 0.5 kg zirconium nitrate in 10 liters of deionized water. After complete dissolution, add 10 kg of attapulgite that has been activated by acid washing with 5% hydrochloric acid and mix evenly. Sonicate at 80°C for 1 hour, and then dry under microwave power of 35 kW for 8 hours to obtain product two. 3. Place 0.3 kg of product one and 4.7 kg of product two mixed powder in a mixer; mix 0.25 kg of glycolic acid, 0.2 kg of polyvinylpyrrolidone and 4 kg of anhydrous ethanol evenly, then add 0.2 kg of ammonium metavanadate, 0.1 kg of ammonium paratungstate, 0.05 kg of cobalt nitrate and 0.05 kg of cerium nitrate. After complete dissolution, the solution is atomized and sprayed into the mixer through an atomizing nozzle, and mixed for 8 hours; after mixing, the temperature is increased to 120°C at 5°C / min, and dried until the powder moisture content is less than 5%, and then calcined at 400°C for 4 hours under a nitrogen atmosphere to obtain the modified attapulgite powder; 4. Grind the modified attapulgite powder obtained in step 3 into 400 mesh, 800 mesh, 1500 mesh and 3000 mesh using an ultrafine grinding mill for later use. 5. Mix 0.1 kg of lactic acid, 0.15 kg of polyethylene oxide, and 0.5 kg of 400 mesh, 0.5 kg of 800 mesh, 1.5 kg of 1500 mesh, and 2.5 kg of 3000 mesh attapulgite powder in a mixer. After the resulting mud is allowed to stand in the dark for 12 hours to age, it is extruded into shape using a honeycomb extruder. The shaped honeycomb denitrification catalyst is dried at 80℃ for 4 days and then calcined at 600℃ for 3 hours to obtain the modified attapulgite honeycomb denitrification catalyst.

[0038] Comparative Example 6 In Comparative Example 4, the mixed powder in step 3 of Example 4 was replaced with an equal amount of commercially available denitrified titanium dioxide, and steps 1 and 2 were omitted. The specific steps are as follows: 1. Place 5 kg of commercial titanium dioxide in a mixer; mix 0.25 kg of glycolic acid, 0.2 kg of polyvinylpyrrolidone and 4 kg of anhydrous ethanol evenly, then add 0.2 kg of ammonium metavanadate, 0.1 kg of ammonium paratungstate, 0.05 kg of cobalt nitrate and 0.05 kg of cerium nitrate. After complete dissolution, the solution is atomized and sprayed into the mixer through an atomizing nozzle, and mixed for 8 hours; after mixing, the temperature is increased to 120°C at 5°C / min, and dried until the moisture content of the powder is less than 5%. Then, calcine at 400°C for 4 hours under a nitrogen atmosphere to obtain titanium dioxide containing active components. 2. The titanium dioxide containing active components obtained in step 1 is ground into 400 mesh, 800 mesh, 1500 mesh and 3000 mesh using an ultrafine grinding mill for later use. 3. Mix 0.1 kg of lactic acid, 0.15 kg of polyethylene oxide, and 0.5 kg of 400 mesh, 0.5 kg of 800 mesh, 1.5 kg of 1500 mesh, and 2.5 kg of 3000 mesh titanium dioxide in a mixer. After the resulting mud is allowed to stand in the dark for 12 hours to age, it is extruded into shape through a honeycomb extruder. The shaped honeycomb denitrification catalyst is dried at 80℃ for 4 days and then calcined at 600℃ for 3 hours to obtain the titanium dioxide honeycomb denitrification catalyst.

[0039] Performance Evaluation The denitrification performance and mechanical strength of the modified attapulgite honeycomb denitrification catalyst and titanium dioxide honeycomb denitrification catalyst prepared in the examples and comparative examples were tested, and the raw material costs were calculated. The results are shown in Table 1.

[0040] Mechanical strength test: The axial compressive strength and radial compressive strength of the attapulgite honeycomb samples were determined using a compressive strength tester in accordance with GB / T 38219-2019 standard.

[0041] Denitrification performance test: The honeycomb catalyst was cut into 2×2 holes with a length of 200 mm and placed in the catalyst reactor. 500 ppm NO and NH3, 5% O2, and N2 were used as carrier gases, and the space velocity was 3000 h⁻¹. -1 The denitrification performance was investigated at two temperature points: 250℃ and 300℃. Each temperature point was held constant for 2 hours. After the reaction stabilized, the NOx conversion rate was calculated using a Testo 350 flue gas analyzer, and the analysis was performed using the following formula.

[0042] NOx conversion rate = ×100%; where C1 is the NOx concentration at the reaction inlet, ppm; and C2 is the NOx concentration at the reaction outlet, ppm. The test results are shown in Table 1.

[0043] Table 1

[0044] As shown in Table 1, the attapulgite-based denitration catalyst prepared based on interfacial reaction overcomes the limitation of conventional denitration catalysts using attapulgite as an auxiliary material. In this invention, the attapulgite doping ratio in each example exceeds 80%, and it maintains high denitration efficiency at different temperatures. Its mechanical strength is superior to the national standard, and the raw material cost of the attapulgite-based catalyst is basically controlled below 6500 yuan. Compared with traditional vanadium-titanium denitration catalysts without waste materials, the raw material cost is reduced by approximately 1500-2500 yuan / m³. 3 about.

[0045] The above embodiments are merely illustrative of the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and substance defined by the claims of the present invention; and such modifications or substitutions are still within the scope defined by the claims of the present invention.

Claims

1. A method for preparing a modified attapulgite honeycomb denitration catalyst, characterized in that, The method comprises the following steps: (a) dissolving nitrogen-containing organic base into deionized water, adding furfural residue after complete dissolution, mixing uniformly, and then obtaining product one after microwave drying; (b) dissolving surfactant, coupling agent and metal salt into deionized water, adding attapulgite after complete dissolution, mixing uniformly, then ultrasonic, and obtaining product two after microwave drying; (c) mixing the mixed powder of product one and product two in a planetary ball mill, mixing uniformly the acid, modifier and anhydrous ethanol, then adding active component metal salt, completely dissolving the solution, and then spraying into the planetary ball mill through an atomizing nozzle for mixing and ball milling; after ball milling, drying, and calcining under nitrogen atmosphere, the modified attapulgite powder is obtained; (d) grinding the modified attapulgite powder into 400 mesh, 800 mesh, 1500 mesh and 3000 mesh through a superfine pulverizer, respectively, to obtain attapulgite powder of 400 mesh, 800 mesh, 1500 mesh and 3000 mesh; (e) mixing the forming aid, binder and attapulgite powder of 400 mesh, 800 mesh, 1500 mesh and 3000 mesh in a mixing machine, obtaining the mud after aging, and then extruding into a honeycomb shape through a honeycomb extruder, drying, and calcining to obtain the modified attapulgite honeycomb denitration catalyst.

2. The production method according to claim 1, characterized by, In step (a), the nitrogen-containing organic base is one or more of tetramethyl ethylenediamine, triethylamine, ephedrine and melamine; In step (a), the weight ratio of nitrogen-containing organic base, furfural residue and deionized water is 0.01-0.1:0.5-1:1; In step (a), the power of microwave drying is 20-40 kW, and the time is 4-8 hours.

3. The preparation method according to claim 1, characterized in that, In step (b), the surfactant is one or more of cetyltrimethylammonium bromide, P123 and polyethylene glycol; the coupling agent is one or more of SCA-1113, NDZ-101 and KH-560; and the metal salt is one or more of iron nitrate, cobalt nitrate, cerium nitrate, chromium nitrate, zirconium nitrate and titanium sulfate; In step (b), the mass ratio of surfactant, coupling agent, metal salt, attapulgite and deionized water is 0.01-0.05:0.005-0.02:0.05-0.2:0.5-1:

1.

4. The method of claim 1, wherein, In step (b), the ultrasonic temperature is 40-80℃, the ultrasonic frequency is 20-60 kHz, and the ultrasonic time is 1-4 hours; the power of microwave drying is 20-40 kW, and the time is 8-12 hours.

5. The preparation method according to claim 1, characterized in that, In step (c), the mass ratio of product one and product two is 0.01-0.1:

1.

6. The method of claim 1, wherein, In step (c), the acid is one of oxalic acid, tartaric acid, citric acid or glycolic acid; the modifier is one of sodium dodecyl sulfate, polyvinylpyrrolidone or polyethyleneimine; and the active component metal salt is one or more of ammonium metavanadate, ammonium paratungstate, ammonium heptamolybdate, titanium sulfate, iron nitrate, cobalt nitrate and cerium nitrate; In step (c), the mass ratio of acid, modifier, anhydrous ethanol and mixed powder is 0.02-0.06:0.01-0.05:0.6-0.8:

1. The mass ratio of the active component metal salt to the mixed powder is 0.05-0.2:

1.

7. The preparation method according to claim 1, characterized in that, In step (c), the ball milling speed is 300-700 r / min, and the ball milling time is 4-8 hours. In step (c), the calcination temperature is 400-600 ℃, and the calcination time is 2-4 hours.

8. The preparation method according to claim 1, characterized in that, In step (e), the molding aid is one or more of lactic acid, polyacrylic acid and polyethylene glycol; and the binder is one or more of carboxymethyl cellulose, polyvinyl alcohol and polyethylene oxide. In step (e), the mass ratio of the 400-mesh, 800-mesh, 1500-mesh and 3000-mesh attapulgite powders is 0.05-0.2:0.1-0.3:0.15-0.3:0.1-0.7; the ratio of the mass of the molding aid to the total mass of the attapulgite powders is 0.01-0.05:1; and the ratio of the mass of the binder to the total mass of the attapulgite powders is 0.01-0.1:

1.

9. The method of claim 1, wherein, In step (e), the light-avoiding standing and aging time is 12-24 hours; the drying temperature is 40-80 ℃, the drying time is 4-6 days; the calcination temperature is 450-600 ℃, and the calcination time is 2-6 hours.

10. A modified attapulgite honeycomb denitration catalyst, characterized in that, Prepared by the preparation method of any one of claims 1-9.

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