A non-ammonia SCR denitration catalyst, its preparation method and application

Abstract

This invention provides a non-ammonia SCR denitration catalyst, its preparation method, and its application. The preparation method includes the following steps: (1) mixing a titanium source and an alcohol solvent to obtain solution A; then mixing a cerium source, nano-oxides, a dispersant, and an additive, adjusting the pH to 1-5 to obtain solution B, wherein the nano-oxides include at least one of nano-alumina, nano-alumina sol, and nano-silica; (2) adding solution B to solution A to form a gel, and obtaining an intermediate after a first drying and a first calcination; (3) impregnating the intermediate with an alkaline solution to obtain an impregnated product; (4) mixing the impregnated product with a copper source and a manganese source, and obtaining the denitration catalyst after a second drying and a second calcination, so that the modified nano-TiO2 encapsulates the nano-oxides, and after calcination, it is subjected to alkaline dissolution treatment, so that the catalyst has the advantages of large specific surface area and high catalytic activity.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a non-ammonia SCR denitration catalyst, its preparation method, and its application. Background Technology

[0002] Nitrogen oxides (NOx) cause pollution such as photochemical smog and the greenhouse effect, seriously endangering human health. To promote the comprehensive development of emission reduction technologies, how to reduce the generation and emission of nitrogen oxides has become one of the main concerns.

[0003] Selective catalytic reduction (SCR) refers to the reaction of a reducing agent with NOx in flue gas under the action of a catalyst to produce non-toxic and pollution-free N2 and H2O. It is a relatively mature NOx purification method. Among them, the SCR technology using ammonia as a reducing agent (NH3-SCR) is widely used in the emission control of NOx from industrial stationary sources. However, ammonia is prone to leakage during production, storage, transportation, and use, causing secondary pollution. More seriously, it can cause combustion, explosion, or poisoning accidents, posing certain dangers. Ammonia can also corrode pipelines. If the flue gas temperature is low, ammonia can also react with sulfur oxides in the flue to form ammonium sulfate, thereby clogging the flue. Therefore, it is necessary to find an economical, long-lasting, environmentally friendly, and safe denitrification technology.

[0004] The incomplete combustion of fossil fuels results in industrial flue gas containing a large amount of CO. For example, the CO concentration in the tail gas of ethylene cracking furnace is higher than the NOx concentration. Therefore, CO can be used as a reducing agent for SCR denitrification without the need for additional reducing agents. This not only saves on the material consumption caused by adding NH3 and avoids the safety hazards caused by NH3 transportation and storage, but also achieves the effect of treating waste with waste and reducing costs.

[0005] Catalysts are the core component of the CO-SCR process, and their preparation process directly affects their catalytic activity, thus impacting NOx conversion efficiency. For example, the catalyst preparation methods disclosed in patent documents CN112121788A, CN101721993B, CN113398921A, CN111229212B, and CN112138665A result in catalysts with small specific surface areas, affecting their activity and denitrification effect. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for preparing a non-ammonia SCR denitration catalyst, so that the catalyst has the advantages of large specific surface area and high catalytic activity, and the preparation process is simple and easy to operate.

[0007] The present invention also provides a non-ammonia SCR denitration catalyst, which is more conducive to the uniform distribution of the active components inside the catalyst, and has the advantages of large specific surface area, high catalytic activity and good stability.

[0008] The present invention also provides a denitrification method, which uses the above-mentioned denitrification catalyst to treat flue gas, which can not only make full use of carbon monoxide in flue gas, but also has the advantages of high denitrification efficiency and good stability, effectively reducing pollutant emissions.

[0009] In a first aspect, the present invention provides a method for preparing a non-ammonia SCR denitration catalyst, comprising the following steps: (1) mixing a titanium source and an alcohol solvent to obtain solution A; then mixing a cerium source, nano-oxide, dispersant, additive, and water, adjusting the pH to 1-5 to obtain solution B, wherein the nano-oxide includes at least one of nano-alumina and nano-silica; (2) adding solution B to solution A to form a gel, and obtaining an intermediate after a first drying and a first calcination; (3) using an alkaline solution to dissolve the intermediate to obtain an alkaline-dissolved product; (4) mixing the alkaline-dissolved product with a copper source and a manganese source, and obtaining a denitration catalyst after a second drying and a second calcination.

[0010] According to one embodiment of the present invention, the titanium source includes at least one of tetrabutyl titanate, titanium sulfate, titanium isopropoxide, and titanium tetrachloride, and the alcohol solvent includes at least one of ethanol and methanol, and the volume ratio of the alcohol solvent to the titanium source is (3-20):1.

[0011] According to one embodiment of the present invention, the cerium source includes at least one of cerium nitrate, cerium sulfate, and cerium chloride; the mass ratio of the cerium source to the titanium source is (5-20):100, wherein the mass of the cerium source is calculated as CeO2 and the mass of the titanium source is calculated as TiO2.

[0012] According to one embodiment of the present invention, the mass ratio of nano-oxide to titanium source is (0.5-5):100, wherein the mass of nano-oxide is calculated as Al2O3.

[0013] According to one embodiment of the present invention, the dispersant includes polyethylene glycol, and the mass ratio of the dispersant to the titanium source is (0.3-5):100; the additive includes glacial acetic acid, and the mass ratio of the additive to the titanium source is (1-5):100, wherein the mass of the titanium source is calculated as TiO2.

[0014] According to one embodiment of the present invention, the temperature of the first drying is 60℃-180℃ and the time is 5h-50h; the temperature of the first calcination is 400℃-680℃ and the time is 2h-35h.

[0015] According to one embodiment of the present invention, the solute of the alkaline solution includes at least one of sodium hydroxide and potassium hydroxide; the concentration of the alkaline solution is 0.1 mol / L-5.0 mol / L, and the volume ratio of the alkaline solution to the intermediate is (0.5-8):1.

[0016] According to one embodiment of the present invention, the copper source includes at least one of copper nitrate, copper sulfate, and copper chloride, and the mass ratio of the copper source to the titanium source is (1-10):100, wherein the copper source is calculated as CuO and the titanium source is calculated as TiO2; the manganese source includes at least one of manganese nitrate, manganese sulfate, manganese chloride, and manganese chlorate, and the mass ratio of the manganese source to the titanium source is (1-15):100, wherein the manganese source is calculated as MnO2 and the titanium source is calculated as TiO2.

[0017] In a second aspect, the present invention provides a non-ammonia SCR denitration catalyst, which is prepared by the above-described preparation method.

[0018] In a third aspect, the present invention provides a flue gas denitrification method, wherein the flue gas is treated with the above-mentioned denitrification catalyst, and the flue gas contains carbon monoxide and nitrogen oxides.

[0019] The implementation of this invention has at least the following beneficial effects:

[0020] The present invention provides a method for preparing a non-ammonia SCR denitration catalyst. The method employs a sol-gel process to incorporate cerium (Ce) into the titanium dioxide (TiO2) lattice, causing lattice distortion. An intermediate is then impregnated with an alkaline solution, which dissolves the nano-oxide particles encapsulated within the intermediate, increasing its specific surface area. Finally, the alkaline-dissolved product is brought into full contact with copper and manganese sources. During a second drying and calcination process, the copper and manganese active components are uniformly dispersed among the titanium dioxide particles, increasing the dispersibility of the active components. The catalyst prepared by this method has advantages such as a large specific surface area and high catalytic activity. Furthermore, the preparation process is simple, easy to operate, and operates under mild conditions, making it environmentally friendly and suitable for practical industrial production and application.

[0021] The non-ammonia SCR denitration catalyst provided by this invention is prepared by the above-mentioned method. The catalyst has advantages such as large specific surface area. The active components copper, cerium and manganese are uniformly dispersed and can play a synergistic role, which greatly improves the catalytic activity of the catalyst. In addition, the doping of cerium in the catalyst improves the catalyst's resistance to alkali metal poisoning and alkaline earth metal poisoning.

[0022] The flue gas denitrification method provided by the present invention uses the above-mentioned catalyst to denitrify the flue gas, which enables carbon monoxide and nitrogen oxides to undergo a catalytic reduction reaction. It can not only remove carbon monoxide and nitrogen oxides at the same time, but also has the advantages of high denitrification efficiency and good stability. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0024] The preparation method of the non-ammonia SCR denitration catalyst provided by the present invention includes the following steps: (1) mixing a titanium source and an alcohol solvent to obtain solution A; then mixing a cerium source, nano oxides, a dispersant, an additive, and water, adjusting the pH to 1-5 to obtain solution B, wherein the nano oxides include at least one of nano alumina and nano silica; (2) adding solution B to solution A to form a gel, and obtaining an intermediate after aging, first drying, and first calcination; (3) performing alkaline dissolution treatment on the intermediate using an alkaline solution; (4) mixing the alkaline-dissolved product with a copper source and a manganese source, and obtaining the denitration catalyst after second drying and second calcination.

[0025] The method for preparing the denitration catalyst provided by this invention involves first incorporating cerium (Ce) into the titanium dioxide (TiO2) lattice using a sol-gel method, thereby encapsulating nano-oxides within the titanium dioxide. Then, an alkaline solution is used to remove the nano-oxides, yielding a treated product. This alkaline-dissolved product is then brought into full contact with copper and manganese sources, and after drying and calcination, a denitration catalyst is obtained. This method allows copper and manganese oxides to be loaded onto a cerium-doped titanium dioxide support. This denitration catalyst possesses advantages such as a large specific surface area and high catalytic activity.

[0026] The inventors, through research and analysis, believe that in steps (1) and (2), by adding solution B to solution A, mixing the cerium source, titanium source, and nano-oxide, and then subjecting the mixture to a first drying and a first calcination, cerium (Ce) is incorporated into the titanium dioxide (TiO2) lattice. Due to the difference in atomic radii between Ce and Ti, lattice distortion occurs during crystal formation, which is beneficial for the generation of oxygen vacancies. Simultaneously, the nano-oxide is encapsulated within the titanium dioxide. In step (3), the intermediate is treated with an alkaline solution, which dissolves the nano-oxide within the intermediate, greatly increasing the nanoscale space and specific surface area of ​​the intermediate. In step (4), the alkaline-dissolved product fully contacts the copper and manganese sources, allowing the active components manganese and copper to fill or disperse within the nanoscale space, further facilitating their dispersion and providing a larger catalytic reaction space. This enhances the catalytic activity of the catalyst. Applying the prepared denitrification catalyst to the CO-SCR process can achieve a denitrification efficiency of over 75%.

[0027] In step (1) above, the titanium source includes at least one of tetrabutyl titanate, titanium sulfate, titanium isopropoxide, and titanium tetrachloride, and the alcohol solvent includes at least one of ethanol and methanol, preferably ethanol. The volume ratio of the alcohol solvent to the titanium source is (3-20):1, preferably (5-10):1. The alcohol solvent enables the titanium source to form titanium hydroxide in solution A, which is beneficial for the formation of titanium dioxide crystals after subsequent calcination.

[0028] In the above embodiments, the cerium source includes at least one of cerium nitrate, cerium sulfate, and cerium chloride. The mass ratio of the cerium source to the titanium source is (5-20):100, preferably (6-12):10, wherein the mass of the cerium source is based on CeO2 and the mass of the titanium source is based on TiO2.

[0029] In the above embodiments, the nano-oxide includes at least one of nano-alumina and nano-silica, or it can be nano-alumina sol. The particle size of the nano-oxide can be 1nm-50nm, preferably 1nm-30nm.

[0030] In the above embodiments, the mass ratio of nano-oxide to titanium source is (0.5-5):100, preferably (0.5-2):100, wherein the mass of nano-oxide is calculated as Al2O3.

[0031] In the above embodiments, the mass ratio of dispersant to titanium source is (0.3-5):100, preferably (0.5-2):100. The dispersant can be polyethylene glycol, and the molecular weight of polyethylene glycol can be 400-10000, preferably 1500-2000.

[0032] In the above embodiments, the additives include glacial acetic acid, and the mass ratio of the additives to the titanium source is (1-5):100, wherein the mass of the titanium source is calculated as TiO2.

[0033] In the specific implementation of this invention, for example, cerium source, nano oxide, polyethylene glycol, glacial acetic acid, ethanol and water can be mixed and stirred, and an acid solution can be added to adjust the pH to 1-5 to obtain solution B, wherein the pH value is preferably 2-4.

[0034] In the above embodiments, step (1) adjusting the pH to 1-5 can be achieved by adding hydrochloric acid, which can be either dilute hydrochloric acid or concentrated hydrochloric acid.

[0035] In the specific implementation of the present invention, step (2) specifically includes: slowly dripping solution B into solution A and stirring, controlling the temperature at a certain level, continuing to stir after the addition is complete to obtain a uniform sol, then obtaining a gel, aging the gel, performing a first drying and a first calcination, and then grinding the solid obtained after calcination to form a powder to obtain an intermediate.

[0036] In step (2) above, on the one hand, cerium is doped into the titanium dioxide lattice, causing lattice defects. After the first calcination, the lattice defects become more stable. On the other hand, nano-oxides are wrapped in titanium dioxide, which helps to form more reaction microspaces, active ingredients distributed on the surface, and a larger specific surface area.

[0037] In the above embodiments, solution B diffuses uniformly in solution A. The stirring process can be mechanical stirring or ultrasonic-assisted stirring. The aging time can be 0.5-10 days, preferably 2-5 days. The purpose of aging is to allow titanium atoms to combine with hydroxyl groups released from the alcohol solvent to generate titanium hydroxide and aggregate into nano-sized particles, which is beneficial for the subsequent formation of titanium dioxide crystals.

[0038] In the above embodiments, the temperature is generally controlled between 10℃ and 90℃, preferably between 20℃ and 60℃. In the specific implementation of the present invention, the temperature of solution A can be controlled between 10℃ and 90℃, and then solution B is added to solution A within the above temperature range.

[0039] In step (2) above, the temperature of the first drying is 60℃-180℃, preferably 60℃-90℃, and the time is 5h-50h, preferably 8h-30h.

[0040] In the above embodiments, the temperature of the first calcination is 400℃-680℃, preferably 450℃-610℃, and the time is 2h-35h, preferably 3h-20h.

[0041] In step (3) of this invention, the intermediate is impregnated with an alkaline solution. The alkaline solution can dissolve the nano-oxides in the intermediate, leaving more space, increasing the specific surface area of ​​the catalyst, which is beneficial to the distribution of active ingredients in space, and also provides space for the active ingredients to contact with the reaction gas, which is beneficial to improving the catalytic efficiency.

[0042] In the above embodiments, the solute of the alkaline solution includes at least one of sodium hydroxide and potassium hydroxide, the concentration of the alkaline solution is 0.1 mol / L-5.0 mol / L, and the volume ratio of the alkaline solution to the catalyst intermediate is (0.5-8):1, preferably (0.8-3):1.

[0043] In the above embodiments, the solid produced after impregnation is further washed. Deionized water can be used as the washing liquid, and the washing is preferably repeated 3-5 times. Then, the impregnated product is obtained by filtration.

[0044] In step (4) of this invention, the impregnation product is mixed with a copper source and a manganese source, and after a second drying and a second calcination, a denitrification catalyst is obtained. Since the impregnation product has more lattice defects, the copper source and manganese source can fill the lattice defects, which is beneficial to improving the dispersibility of the active components.

[0045] In the specific implementation of this invention, the impregnation product, copper source, manganese source and water can be mixed to make a mud with a water content of 30%-35%. Then, the mud is dried and calcined a second time to obtain a denitrification catalyst.

[0046] In the above embodiments, the temperature of the second drying is 60℃-180℃, preferably 80℃-120℃, and the time is 5h-50h, preferably 8h-30h.

[0047] In the above embodiments, the temperature of the second calcination is 400℃-680℃, preferably 450℃-610℃, and the time is 2h-35h, preferably 3h-20h.

[0048] In the above embodiments, the copper source includes at least one of copper nitrate, copper sulfate, and copper chloride, preferably copper nitrate, and the mass ratio of copper source to titanium source is (1-10):100, preferably (2-5):100, wherein the copper source is calculated as CuO and the titanium source is calculated as TiO2.

[0049] In the above embodiments, the manganese source includes at least one of manganese nitrate, manganese sulfate, manganese chloride, and manganese chlorate, preferably manganese nitrate. The mass ratio of manganese source to titanium source is (1-15):100, preferably (2-6):100, wherein the manganese source is calculated as MnO2 and the titanium source is calculated as TiO2.

[0050] In the above embodiments, after the second calcination, the product after the second calcination is further ground to obtain a denitrification catalyst.

[0051] The denitrification catalyst provided by the present invention is prepared by the above-mentioned preparation method. The denitrification catalyst uses titanium dioxide as a support and cerium, manganese and copper as active components of the denitrification catalyst. The denitrification efficiency of the catalyst can reach more than 75%.

[0052] In the above-mentioned denitrification catalysts, the mass ratio of titanium dioxide, cerium, manganese, and copper is generally equal to the mass of the cerium source, titanium source, manganese source, and copper source in the preparation process.

[0053] In the above-mentioned denitrification catalyst, cerium is doped into the lattice of titanium dioxide, and manganese and copper oxides are supported on the titanium dioxide support. The active components cerium, manganese and copper are uniformly dispersed on the titanium dioxide support. Cerium, manganese and copper play a synergistic role, which enables carbon monoxide to preferentially undergo catalytic reduction reaction with nitrogen oxides, thereby improving the denitrification efficiency. In addition, the doping of cerium improves the catalyst's resistance to alkali metal poisoning and alkaline earth metal poisoning.

[0054] The flue gas denitrification method provided by the present invention uses the above-mentioned denitrification catalyst to denitrify the flue gas, wherein the flue gas contains carbon monoxide and nitrogen oxides.

[0055] The denitrification method provided by the present invention uses carbon monoxide in flue gas as a reducing agent and the above-mentioned denitrification catalyst as a catalyst for SCR denitrification. The specific process includes: placing the denitrification catalyst in a reactor, introducing a mixed gas containing oxygen and nitrogen, heating it to 350°C, and simultaneously introducing flue gas to allow the flue gas to fully contact the catalyst for denitrification treatment.

[0056] In the above embodiments, the flue gas also contains SO2, and nitrogen oxides include NO. Using the catalyst provided by this invention for denitrification treatment enables carbon monoxide in the flue gas to preferentially undergo a catalytic reduction reaction with nitrogen oxides, inhibiting the reaction of carbon monoxide with oxygen in the flue gas, thus improving the denitrification efficiency to achieve a denitrification efficiency of over 75.2%.

[0057] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0058] In all the examples and comparative examples, all other chemicals used were commercially available chemically pure reagents. The catalysts prepared in the examples and comparative examples were evaluated using the following assay methods:

[0059] (1) Specific surface area

[0060] The catalyst was ground, and a 60-80 mesh sample was taken. The specific surface area of ​​the sample was determined by BET adsorption method.

[0061] (2) Denitrification efficiency

[0062] Using the catalysts prepared in the examples and comparative examples as denitrification catalysts, the flue gas was denitrified according to the following flue gas denitrification method:

[0063] The catalyst was ground, and samples of 60-80 mesh were collected by sieving. 1-1.5g of the sample was placed in a fixed-bed reactor, and a mixture of oxygen and nitrogen was introduced. The temperature was raised to 350℃, and flue gas was introduced simultaneously to ensure full contact between the flue gas and the catalyst for denitrification treatment. The concentrations of each component in the flue gas and tail gas were measured using a flue gas analyzer. The NOx conversion rate and SO2 / SO3 conversion rate were calculated according to the formula: NOx conversion rate = (NOx concentration in flue gas - NOx concentration in tail gas) / NOx concentration in flue gas, and SO2 / SO3 conversion rate = (SO2 concentration in flue gas - SO2 concentration in tail gas) / SO2 concentration in flue gas.

[0064] The flue gas analyzer is a Siemens ULTRAMAT23 continuous online flue gas analyzer; the content of each component in the flue gas is as follows: carbon monoxide (CO) is 500 mg / Nm³. 3 Nitric oxide (NO) concentration was 500 mg / Nm³. 3Sulfur dioxide (SO2) was 700 mg / Nm³. 3 A standard gas meter was used. The O2 content in the reactor was 3% (v), and the NO, CO, and SO2 contents were all 5% (v). Nitrogen was used as a balance gas. The manufacturers of NO, CO, SO2, and N2 were all Dalian Date Gas Co., Ltd. The O2 came from the public utility air pipeline network at a pressure of 0.4-0.6 MPa, and the N2 came from the public utility nitrogen pipeline network with a purity of 99.0% (v) and a pressure of 0.4-0.6 MPa.

[0065] Reaction conditions: Volume hourly space velocity (VHSV) of 20,000 h⁻¹ -1 Temperature 350℃;

[0066] The evaluation results are shown in Table 1.

[0067] Example 1

[0068] Solution A is prepared by mixing 100g of titanium source with first ethanol. Solution B is prepared by mixing 6g of cerium salt, 0.5g of nano-aluminum sol, 0.5g of polyethylene glycol, 3mL of glacial acetic acid, and second ethanol, adjusting the pH to 2 with hydrochloric acid, and then sonicating. The mass of titanium source is calculated as TiO2, the mass of cerium source is calculated as CeO2, and the mass of nano-aluminum sol is calculated as Al2O3. The titanium source is tetrabutyl titanate, the cerium source is cerium nitrate, the volume ratio of first ethanol to titanium source is 5:1, and the volumes of first ethanol and second ethanol are equal.

[0069] The temperature of solution A was controlled at 22℃. Solution B was slowly added to solution A and stirred. After the addition was complete, a gel was obtained. The gel was aged at room temperature for 2 days, then dried at 60℃ for 30 hours, and then calcined in a muffle furnace at 450℃ for 20 hours. The obtained solid was ground to obtain an intermediate.

[0070] The intermediate was impregnated with a 0.1 mol / L sodium hydroxide solution, and the impregnated product was obtained after washing and filtration, wherein the volume ratio of sodium hydroxide solution to intermediate was 1:1.

[0071] The impregnation product was mixed with 2g of copper source, 4g of manganese source and water to prepare a mud with a water content of 30%. The mud was dried at 120℃ for 5h and then calcined at 510℃ for 5h to obtain denitrification catalyst S1. The mass of copper source is CuO and the mass of manganese source is MnO2. The copper source is copper nitrate and the manganese source is manganese nitrate.

[0072] Comparative Example 1

[0073] Compared with Example 1, the step of "impregnating the intermediate with a sodium hydroxide solution of concentration of 0.1 mol / L" is omitted, while other conditions remain unchanged.

[0074] Example 2

[0075] Solution A is prepared by mixing 100g of titanium source with first ethanol; solution B is prepared by mixing 10g of cerium salt, 1g of nano-alumina, 1.5g of polyethylene glycol, 1mL of glacial acetic acid, and second ethanol, adjusting the pH to 3 with hydrochloric acid, and then sonicating; wherein the mass of titanium source is TiO2, the mass of cerium source is CeO2, and the mass of nano-alumina is Al2O3; the titanium source is titanium sulfate, the cerium source is cerium sulfate, the volume ratio of first ethanol to titanium source is 10:1, and the volume ratio of second ethanol to first ethanol is 1.2:1.

[0076] The temperature of solution A was controlled at 30℃. Solution B was slowly added to solution A and stirred. After the addition was complete, a gel was obtained. The gel was aged at room temperature for 3 days, then dried at 70℃ for 25 hours, and then calcined in a muffle furnace at 550℃ for 10 hours. The obtained solid was ground to obtain an intermediate.

[0077] The intermediate was impregnated with a 0.9 mol / L sodium hydroxide solution, and the impregnated product was obtained after washing and filtration, wherein the volume ratio of sodium hydroxide solution to intermediate was 1.8:1.

[0078] The impregnation product was mixed with 3g of copper source, 6g of manganese source and water to prepare a mud with a water content of 35%. The mud was dried at 100℃ for 9h and then calcined at 450℃ for 15h to obtain denitrification catalyst S2. The mass of copper source is CuO and the mass of manganese source is MnO2. The copper source is copper sulfate and the manganese source is manganese chlorate.

[0079] Example 3

[0080] Solution A is prepared by mixing 100g of titanium source with first ethanol. Solution B is prepared by mixing 7g of cerium salt, 1.5g of nano-alumina, 1.5g of polyethylene glycol, 4mL of glacial acetic acid, and second ethanol, adjusting the pH to 4 with hydrochloric acid, and then sonicating. The mass of titanium source is calculated as TiO2, the mass of cerium source is calculated as CeO2, and the mass of nano-silica is calculated as Al2O3. The titanium source is titanium isopropoxide, the cerium source is cerium sulfate, the volume ratio of first ethanol to titanium source is 7:1, and the volume ratio of second ethanol to first ethanol is 1.5:1.

[0081] The temperature of solution A was controlled at 50℃. Solution B was slowly added to solution A and stirred. After the addition was complete, a gel was obtained. The gel was aged at room temperature for 5 days, then dried at 90℃ for 19 hours, and then calcined in a muffle furnace at 500℃ for 10 hours. The obtained solid was ground to obtain an intermediate.

[0082] The intermediate was impregnated with a 1.5 mol / L sodium hydroxide solution, and the impregnated product was obtained after washing and filtration, wherein the volume ratio of sodium hydroxide solution to intermediate was 1.5:1.

[0083] The impregnation product was mixed with 4g of copper source, 4g of manganese source and water to prepare a mud with a water content of 35%. The mud was dried at 100℃ for 9h and then calcined at 450℃ for 15h to obtain denitrification catalyst S3. The mass of copper source is CuO and the mass of manganese source is MnO2. The copper source is copper nitrate and the manganese source is manganese chlorate.

[0084] Example 4

[0085] Solution A is prepared by mixing 100g of titanium source with first ethanol. Solution B is prepared by mixing 10g of cerium salt, 1.5g of nano-alumina, 2g of polyethylene glycol, 5mL of glacial acetic acid, and second ethanol, adjusting the pH to 3 with hydrochloric acid, and then sonicating. The mass of titanium source is calculated as TiO2, the mass of cerium source is calculated as CeO2, and the mass of nano-alumina is calculated as Al2O3. The titanium source is titanium isopropoxide, the cerium source is cerium sulfate, the volume ratio of first ethanol to titanium source is 5:1, and the volume of second ethanol is equal to that of first ethanol.

[0086] The temperature of solution A was controlled at 60℃. Solution B was slowly added to solution A and stirred. After the addition was complete, a gel was obtained. The gel was aged at room temperature for 5 days, then dried at 80℃ for 15 hours, and then calcined in a muffle furnace at 570℃ for 6 hours. The obtained solid was ground to obtain an intermediate.

[0087] The intermediate was impregnated with a 3.5 mol / L sodium hydroxide solution, and the impregnated product was obtained after washing and filtration, wherein the volume ratio of sodium hydroxide solution to intermediate was 2:1.

[0088] The impregnation product was mixed with 5g of copper source, 3g of manganese source and water to prepare a mud with a water content of 32%. The mud was dried at 110℃ for 12h and then calcined at 520℃ for 15h to obtain denitrification catalyst S4. The mass of copper source is CuO and the mass of manganese source is MnO2. The copper source is copper nitrate and the manganese source is manganese chlorate.

[0089] Example 5

[0090] Solution A is prepared by mixing 100g of titanium source with first ethanol. Solution B is prepared by mixing 11g of cerium salt, 2g of nano-alumina, 2g of polyethylene glycol, 4mL of glacial acetic acid, and second ethanol, adjusting the pH to 3 with hydrochloric acid, and then sonicating. The mass of titanium source is calculated as TiO2, the mass of cerium source is calculated as CeO2, and the mass of nano-alumina is calculated as Al2O3. The titanium source is titanium isopropoxide, the cerium source is cerium sulfate, the volume ratio of first ethanol to titanium source is 8:1, and the volume ratio of second ethanol to first ethanol is 0.8:1.

[0091] The temperature of solution A was controlled at 40℃. Solution B was slowly added to solution A and stirred. After the addition was complete, a gel was obtained. The gel was aged at room temperature for 3 days, then dried at 90℃ for 20 hours, and then calcined in a muffle furnace at 460℃ for 8 hours. The obtained solid was ground to obtain an intermediate.

[0092] The intermediate was impregnated with a 0.5 mol / L sodium hydroxide solution, and the impregnated product was obtained after washing and filtration, wherein the volume ratio of sodium hydroxide solution to intermediate was 3:1.

[0093] The impregnation product was mixed with 2g of copper source, 3g of manganese source, and water to prepare a slurry with a moisture content of 30%. The slurry was dried at 100℃ for 8 hours and then calcined at 480℃ for 10 hours to obtain the denitrification catalyst S5. The mass of the copper source was calculated as CuO, and the mass of the manganese source was calculated as MnO2. The copper source was copper nitrate, and the manganese source was manganese chlorate. This catalyst sample has been subjected to denitrification operation for 2000 hours. The results in Table 1 are the average values ​​of its operation from 1960 to 2000 hours.

[0094] Table 1

[0095]

[0096] As shown in Table 1, the catalyst prepared by the method provided in this invention has a specific surface area of ​​46 m². 2 / g-59m 2 / g, using this catalyst for flue gas denitrification can achieve a denitrification efficiency of over 75.2%. The inventors believe through research and analysis that the active components copper, cerium and manganese have a synergistic effect, which can cause carbon monoxide and nitrogen oxides in flue gas to undergo catalytic reduction reaction, thereby improving the denitrification efficiency.

[0097] The preferred embodiments and experimental verifications of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for preparing a non-ammonia SCR denitration catalyst, characterized in that, Includes the following steps: (1) Mix titanium source and alcohol solvent to obtain solution A; then mix cerium source, nano oxide, dispersant, additive and water, adjust pH to 1-5 to obtain solution B, wherein the nano oxide includes nano alumina; wherein the particle size of the nano oxide is 1nm-50nm; (2) The solution B is added to the solution A to form a gel, and after a first drying and a first calcination, an intermediate containing the nano-oxide is obtained; (3) The intermediate is dissolved in an alkaline solution to dissolve the nano-oxides encapsulated in the intermediate and obtain an alkaline dissolved product; (4) The alkaline-soluble product is mixed with a copper source and a manganese source, and after a second drying and a second calcination, the denitrification catalyst is obtained; The mass ratio of the nano-oxide to the titanium source is (0.5-5):100, wherein the mass of the nano-oxide is calculated as Al2O3; the mass ratio of the auxiliary agent to the titanium source is (1-5):100, wherein the mass of the titanium source is calculated as TiO2; the concentration of the alkaline solution is 0.1mol / L-5.0mol / L, and the volume ratio of the alkaline solution to the intermediate is (0.5-8):

1.

2. The preparation method according to claim 1, characterized in that, The titanium source includes at least one of tetrabutyl titanate, titanium sulfate, titanium isopropoxide, and titanium tetrachloride, and the alcohol solvent includes at least one of ethanol and methanol. The volume ratio of the alcohol solvent to the titanium source is (3-20):

1.

3. The preparation method according to claim 1 or 2, characterized in that, The cerium source includes at least one of cerium nitrate, cerium sulfate, and cerium chloride; The mass ratio of the cerium source to the titanium source is (5-20):100, wherein the mass of the cerium source is calculated as CeO2 and the mass of the titanium source is calculated as TiO2.

4. The preparation method according to any one of claims 1-2, characterized in that, The dispersant includes polyethylene glycol, and the mass ratio of the dispersant to the titanium source is (0.3-5):100; The additives include glacial acetic acid.

5. The preparation method according to any one of claims 1-2, characterized in that, The first drying temperature is 60℃-180℃, and the time is 5h-50h; The first roasting temperature is 400℃-680℃, and the time is 2h-35h.

6. The preparation method according to any one of claims 1-2, characterized in that, The solute in the alkaline solution includes at least one of sodium hydroxide and potassium hydroxide.

7. The preparation method according to any one of claims 1-2, characterized in that, The copper source includes at least one of copper nitrate, copper sulfate, and copper chloride, and the mass ratio of the copper source to the titanium source is (1-10):100, wherein the copper source is calculated as CuO and the titanium source is calculated as TiO2; The manganese source includes at least one of manganese nitrate, manganese sulfate, manganese chloride, and manganese chlorate, and the mass ratio of the manganese source to the titanium source is (1-15):100, wherein the manganese source is calculated as MnO2 and the titanium source is calculated as TiO2.

8. A non-ammonia SCR denitration catalyst, characterized in that, It is prepared by the preparation method according to any one of claims 1-7.

9. A method for flue gas denitrification, characterized in that, The denitrification catalyst described in claim 8 is used to denitrify the flue gas, wherein the flue gas contains carbon monoxide and nitrogen oxides.

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