SCR denitration catalyst and preparation method thereof
By using composite porous titanium dioxide and manganese and cerium elements in SCR denitrification catalysts, combined with secondary modification and calcination activation processes, the problems of low selectivity and uneven dispersion of existing catalysts at high temperatures are solved, and efficient and stable denitrification effect is achieved.
Patent Information
- Application Number
- CN202411827281.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-04-29
AI Technical Summary
The existing SCR denitrification catalysts have low selectivity for N2 under high temperature conditions and are prone to inactivation. During the preparation process, there are problems such as uneven dispersion of the carrier porous titanium dioxide and uneven loading of the active components, resulting in weak catalyst effects.
The SCR denitrification catalyst was prepared by co-precipitation method, and composite porous titanium dioxide was used as the support, and manganese and cerium were introduced as active components. The activity and denitrification efficiency of the catalyst were improved through secondary modification and primary calcination, acid activation, secondary calcination and other processes.
It improves the low-temperature application and chemical stability of the catalyst, enhances the resistance to sulfur poisoning, improves the denitrification efficiency and the service life of the catalyst, and reduces operating costs.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of denitration catalysts, and in particular to an SCR denitration catalyst and a preparation method thereof. Background Art
[0002] With the acceleration of industrialization and urbanization, nitrogen oxides (NO x ) The increasing emissions have become a global environmental problem. x It is not only one of the main sources of air pollution, but also a key factor leading to environmental problems such as photochemical smog and acid rain. x Emissions and reducing their impact on the environment have become an important issue in the current field of environmental protection.
[0003] In the existing technology, the commonly used commercial SCR denitrification catalyst is mainly V2O5-WO3 (MoO3) / TiO2. Although it is widely used, its inherent defects cannot be ignored. This type of catalyst contains highly toxic components, which poses a potential threat to the environment. At the same time, under high temperature conditions, its selectivity for N2 is low and it is easy to deactivate, which not only leads to catalyst poisoning and performance degradation, but also greatly shortens its service life, thereby increasing the overall operating cost.
[0004] The most critical thing is that there are the following defects in the catalyst production process: when the porous titanium dioxide particles on the carrier are loaded with active components, due to the secondary agglomeration phenomenon and uneven dispersion problems, the loading amount of the active components is low and the loading is uneven, making the catalyst effect weak. On the other hand, if a dispersant is used to inhibit the aggregation of porous titanium dioxide particles, after calcination, there will be residual carbon and other substances covering the active sites, reducing the specific surface area of the catalyst, thus greatly affecting the performance of the catalyst.
[0005] In summary, it is of great significance to solve the above problems and prepare a high-performance SCR denitration catalyst and its preparation method. Summary of the invention
[0006] The object of the present invention is to provide an SCR denitration catalyst and a preparation method thereof to solve the problems raised in the above background technology.
[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: A method for preparing an SCR denitration catalyst comprises the following steps: Step 1: Add the composite porous titanium dioxide to ethanol, disperse it evenly at a speed of 3000-5000 r / min in an ice bath, then add manganese nitrate tetrahydrate and cerium nitrate hexahydrate and mix them evenly, add ammonium hydroxide dropwise until the pH is 9.0-10.0, age it at 20-40° C. for 10-14 hours, centrifuge, wash, dry, grind and sieve it; obtain a precursor catalyst; Step 2: The precursor catalyst is subjected to the steps of primary calcination, acid activation, and secondary calcination in sequence to obtain an SCR denitration catalyst.
[0008] In the scheme, the co-precipitation method is adopted to prepare the SCR denitrification catalyst; composite porous titanium dioxide is used as the carrier material, and manganese and cerium elements are introduced as active components to synergistically promote the activity of the catalyst and improve the denitrification efficiency.
[0009] Among them, porous titanium dioxide is widely used in catalysts due to its porosity, abundant active sites and large specific surface area. However, during the preparation process, titanium dioxide has insufficient dispersion and secondary agglomeration, which makes the prepared catalyst have low active component load, reduced active sites and reduced denitrification efficiency.
[0010] Therefore, this scheme adopts secondary modification, using non-polar bonds to generate steric hindrance and enhance the dispersibility of titanium dioxide. At the same time, polar groups such as pyridine and hydroxyl are introduced to promote subsequent complexation with metal ions, promote the loading of active components, and improve the loading uniformity, thereby improving the activity of the catalyst and improving the denitrification efficiency.
[0011] Among them, manganese as an active component can enhance the low-temperature applicability of the catalyst, reduce the temperature of denitrification, and reduce energy consumption. Cerium as an active component can improve the chemical stability of the catalyst and its resistance to sulfur poisoning; at the same time, it can enhance the reducibility and oxygen storage capacity of the catalyst.
[0012] In the subsequent plan, the processes of primary calcination, acid activation, and secondary calcination were adopted to solve the problems of surface active sites being covered and pore size being blocked by impurities, further increase the overall specific surface area of the catalyst, increase the active sites, and thus improve the denitrification efficiency of the catalyst.
[0013] More optimally, in the raw materials of the SCR denitration catalyst, the mass ratio of composite porous titanium dioxide, manganese nitrate tetrahydrate, and cerium nitrate hexahydrate is 8-11:0.3-0.8:0.8.
[0014] More optimally, the specific steps of step 2 are: (1) placing the precursor catalyst in an air atmosphere, setting the temperature to 500~600℃, calcining it once for 3~4 hours, cooling it down, and obtaining catalyst A; (2) placing catalyst A in a 0.1~0.15 mol / L perchloric acid aqueous solution, stirring it at 30~50℃ for 6~8 hours, washing and drying it, and obtaining an activated catalyst A; (3) placing the activated catalyst A in a nitrogen atmosphere, setting the temperature to 200~300℃, heat treating it for 1~2 hours, cooling it, and obtaining an SCR denitration catalyst.
[0015] In a further scheme, the precursor catalyst is calcined once in an air atmosphere. The oxygen in the air can remove the carbon produced by calcination of organic matter on the surface of the composite porous titanium dioxide and block the pores, thereby greatly reducing the active sites and specific surface area in the catalyst and affecting the overall performance of the catalyst. Subsequently, acid activation is performed to remove some impurities in the gaps to prevent impurities from affecting the overall performance of the catalyst and increase the active sites.
[0016] More optimally, the mesh size of the grinding and sieving is 60-90 meshes.
[0017] More optimally, the preparation process of the composite porous titanium dioxide is: Step 1: adding titanyl sulfate to deionized water, adding ammonia water, aging at 20-30°C for 8-12 hours, drying, calcining at 500-600°C for 3-4 hours, grinding, and obtaining porous titanium dioxide; Step 2: adding porous titanium dioxide and diisopropanolamine to a 5-10 wt% ethylene glycol-ethanol solution, and ultrasonically dispersing at 45-55° C. for 2-5 hours to obtain primary modified titanium dioxide; Step 3: Add the primary modified titanium dioxide and silane coupling agent to a 30-35wt% ethanol aqueous solution, add glacial acetic acid and 20-30wt% ammonia water dropwise at 30-50°C to adjust the pH to 4.0-7.0, then ultrasonically disperse for 1-2 hours, wash, filter and dry to obtain a composite porous titanium dioxide.
[0018] More optimally, the raw materials of the porous titanium dioxide include the following components: 5-6 parts of titanyl sulfate, 30-40 parts of deionized water, and 1-2 parts of ammonia water, by mass.
[0019] More optimally, the raw materials of the primary modified titanium dioxide include the following components: 3-4 parts of porous titanium dioxide, 4-6 parts of diisopropanolamine, and 32-40 parts of 5-10 wt% ethylene glycol-ethanol solution, by weight; The raw materials of the composite porous titanium dioxide include the following components: 3-4 parts of primary modified titanium dioxide, 4-5 parts of silane coupling agent, and 30-40 parts of 30-35wt% ethanol aqueous solution, by weight.
[0020] More optimally, the preparation method of the silane coupling agent is: 1-pyridinepentenol and mercaptopropyltrimethoxysilane are added to tetrahydrofuran in a molar ratio of 1:1~1.1 in sequence, and azobisisobutyronitrile is added and stirred evenly; under ultraviolet light, a click reaction is carried out for 2~4 hours, and the solvent is evaporated to obtain the silane coupling agent.
[0021] Compared with the prior art, the present invention has the following beneficial effects: The SCR denitration catalyst of the present invention uses composite porous titanium dioxide as a carrier material and manganese and cerium as active components to synergistically promote the activity of the catalyst and improve the denitration efficiency. Through secondary modification, the problems of poor dispersibility and secondary agglomeration in the preparation of traditional titanium dioxide are solved; and through processes such as primary calcination, acid activation, and secondary calcination, the problem of impurities blocking the pore size due to subsequent calcination is solved, the specific surface area is enhanced, the active sites are increased, and the denitration efficiency of the catalyst is further improved. DETAILED DESCRIPTION
[0022] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0023] It should be noted that the following parts are by mass. All raw materials involved in the present invention are purchased from manufacturers without any special restrictions. Examples include: In the following embodiments, the CAS number of 1-pyridinepentenol is 79108-44-4, purchased from Shanghai Luoyin Fluorine Chemical Co., Ltd.; the CAS number of mercaptopropyltrimethoxysilane is 4420-74-0, purchased from Anhui Aiyota Silicone Oil Co., Ltd.; the item number of anatase titanium dioxide is 15 kg, purchased from Xuancheng Jingrui New Materials Co., Ltd.
[0024] Example 1: A method for preparing an SCR denitration catalyst, comprising the following steps: Step 1: Preparation of silane coupling agent: 1-pyridinepentenol and mercaptopropyltrimethoxysilane are added to tetrahydrofuran in a molar ratio of 1:1, and azobisisobutyronitrile is added and stirred evenly; click reaction is carried out under ultraviolet light for 3 hours, and the solvent is evaporated to obtain a silane coupling agent; Step 2: Preparation of composite porous titanium dioxide: (1) Add 5.5 parts of titanium oxysulfate to 35 parts of deionized water, add 1.5 parts of ammonia water, age at 25°C for 10 hours, dry, calcine at 550°C for 3.5 hours, grind to obtain porous titanium dioxide; (2) Add 3.5 parts of porous titanium dioxide and 5 parts of diisopropanolamine to 36 parts of 7.5wt% ethylene glycol-ethanol solution, ultrasonically disperse at 50°C for 3.5 hours to obtain primary modified titanium dioxide; (3) Add 3.5 parts of primary modified titanium dioxide and 4.5 parts of silane coupling agent to 35 parts of 32wt% ethanol aqueous solution, add glacial acetic acid and 25wt% ammonia water dropwise at 40°C to adjust the pH to 5.5, then ultrasonically disperse for 1.5 hours, wash, filter and dry to obtain composite porous titanium dioxide; Step 3: Add the composite porous titanium dioxide to ethanol, disperse it evenly at a speed of 4000r / min under an ice bath, then add manganese nitrate tetrahydrate and cerium nitrate hexahydrate and mix them evenly, the mass ratio of the composite porous titanium dioxide, manganese nitrate tetrahydrate and cerium nitrate hexahydrate is 9.5:0.5:0.8, add ammonium hydroxide dropwise until the pH is 9.5, age at 30°C for 12 hours, centrifuge, wash, dry, grind and sieve 75 mesh; obtain a precursor catalyst; Step 4: (1) Place the precursor catalyst in an air atmosphere, set the temperature to 550°C, calcine it once for 3.5 hours, cool it down, and obtain catalyst A; (2) Place catalyst A in a 0.12 mol / L perchloric acid aqueous solution, stir it at 40°C for 7 hours, wash and dry it to obtain activated catalyst A; (3) Place the activated catalyst A in a nitrogen atmosphere, set the temperature to 250°C, heat treat it for 1.5 hours, cool it, and obtain an SCR denitration catalyst.
[0025] Embodiment 2: A method for preparing a SCR denitration catalyst, comprising the following steps: Step 1: Preparation of silane coupling agent: 1-pyridinepentenol and mercaptopropyltrimethoxysilane are added to tetrahydrofuran in a molar ratio of 1:1, and azobisisobutyronitrile is added and stirred evenly; click reaction is carried out under ultraviolet light for 3 hours, and the solvent is evaporated to obtain a silane coupling agent; Step 2: Preparation of composite porous titanium dioxide: (1) Add 5 parts of titanium oxysulfate to 30 parts of deionized water, add 1 part of ammonia water, age at 20°C for 8 hours, dry, calcine at 550°C for 3.5 hours, grind to obtain porous titanium dioxide; (2) Add 3 parts of porous titanium dioxide and 4 parts of diisopropanolamine to 36 parts of 7.5wt% ethylene glycol-ethanol solution, ultrasonically disperse at 50°C for 3.5 hours to obtain primary modified titanium dioxide; (3) Add 3 parts of primary modified titanium dioxide and 4 parts of silane coupling agent to 30 parts of 32wt% ethanol aqueous solution, add glacial acetic acid and 25wt% ammonia water dropwise at 40°C to adjust the pH to 5.5, then ultrasonically disperse for 1.5 hours, wash, filter and dry to obtain composite porous titanium dioxide; Step 3: Add the composite porous titanium dioxide to ethanol, disperse it evenly at a speed of 4000r / min in an ice bath, then add manganese nitrate tetrahydrate and cerium nitrate hexahydrate and mix them evenly, the mass ratio of the composite porous titanium dioxide, manganese nitrate tetrahydrate and cerium nitrate hexahydrate is 8:0.3:0.8, add ammonium hydroxide dropwise until the pH is 9.5, age at 30°C for 12 hours, centrifuge, wash, dry, grind and sieve 75 mesh; obtain a precursor catalyst; Step 4: (1) Place the precursor catalyst in an air atmosphere, set the temperature to 550°C, calcine it once for 3.5 hours, cool it down, and obtain catalyst A; (2) Place catalyst A in a 0.12 mol / L perchloric acid aqueous solution, stir it at 40°C for 7 hours, wash and dry it to obtain activated catalyst A; (3) Place the activated catalyst A in a nitrogen atmosphere, set the temperature to 250°C, heat treat it for 1.5 hours, cool it, and obtain an SCR denitration catalyst.
[0026] Embodiment 3: A method for preparing a SCR denitration catalyst, comprising the following steps: Step 1: Preparation of silane coupling agent: 1-pyridinepentenol and mercaptopropyltrimethoxysilane are added to tetrahydrofuran in a molar ratio of 1:1, and azobisisobutyronitrile is added and stirred evenly; click reaction is carried out under ultraviolet light for 3 hours, and the solvent is evaporated to obtain a silane coupling agent; Step 2: Preparation of composite porous titanium dioxide: (1) Add 6 parts of titanyl sulfate to 40 parts of deionized water, add 2 parts of ammonia water, age at 30°C for 12 hours, dry, calcine at 550°C for 3.5 hours, grind to obtain porous titanium dioxide; (2) Add 4 parts of porous titanium dioxide and 6 parts of diisopropanolamine to 36 parts of 7.5wt% ethylene glycol-ethanol solution, ultrasonically disperse at 50°C for 3.5 hours to obtain primary modified titanium dioxide; (3) Add 4 parts of primary modified titanium dioxide and 5 parts of silane coupling agent to 40 parts of 32wt% ethanol aqueous solution, add glacial acetic acid and 25wt% ammonia water dropwise at 40°C to adjust the pH to 5.5, then ultrasonically disperse for 1.5 hours, wash, filter and dry to obtain composite porous titanium dioxide; Step 3: Add the composite porous titanium dioxide to ethanol, disperse it evenly at a speed of 4000r / min in an ice bath, then add manganese nitrate tetrahydrate and cerium nitrate hexahydrate and mix them evenly, the mass ratio of the composite porous titanium dioxide, manganese nitrate tetrahydrate and cerium nitrate hexahydrate is 11:0.8:0.8, add ammonium hydroxide dropwise until the pH is 9.5, age at 30°C for 12 hours, centrifuge, wash, dry, grind and sieve 75 mesh; obtain a precursor catalyst; Step 4: (1) Place the precursor catalyst in an air atmosphere, set the temperature to 550°C, calcine it once for 3.5 hours, cool it down, and obtain catalyst A; (2) Place catalyst A in a 0.12 mol / L perchloric acid aqueous solution, stir it at 40°C for 7 hours, wash and dry it to obtain activated catalyst A; (3) Place the activated catalyst A in a nitrogen atmosphere, set the temperature to 250°C, heat treat it for 1.5 hours, cool it, and obtain an SCR denitration catalyst.
[0027] Comparative Example 1: Based on Example 1, anatase titanium dioxide was used as a carrier, and the rest of the process remained unchanged, specifically: Step 1: Add anatase titanium dioxide to ethanol, disperse it evenly at a speed of 4000r / min in an ice bath, then add manganese nitrate tetrahydrate and cerium nitrate hexahydrate and mix them evenly, the mass ratio of anatase titanium dioxide, manganese nitrate tetrahydrate and cerium nitrate hexahydrate is 9.5:0.5:0.8, add ammonium hydroxide dropwise until the pH is 9.5, age at 30°C for 12 hours, centrifuge, wash, dry, grind and sieve 75 mesh; obtain a precursor catalyst; Step 2: (1) Place the precursor catalyst in an air atmosphere, set the temperature to 550°C, calcine it once for 3.5 hours, cool it down, and obtain catalyst A; (2) Place catalyst A in a 0.12 mol / L perchloric acid aqueous solution, stir it at 40°C for 7 hours, wash and dry it to obtain activated catalyst A; (3) Place the activated catalyst A in a nitrogen atmosphere, set the temperature to 250°C, heat treat it for 1.5 hours, cool it, and obtain an SCR denitration catalyst.
[0028] Comparative Example 2: Based on Example 1, the primary modified titanium dioxide was used instead of the composite porous titanium dioxide, and the other processes remained unchanged, specifically: Step 1: Preparation of composite porous titanium dioxide: (1) Add 5.5 parts of titanium oxysulfate to 35 parts of deionized water, add 1.5 parts of ammonia water, age at 25°C for 10 hours, dry, calcine at 550°C for 3.5 hours, grind to obtain porous titanium dioxide; (2) Add 3.5 parts of porous titanium dioxide and 5 parts of diisopropanolamine to 36 parts of 7.5wt% ethylene glycol-ethanol solution, ultrasonically disperse at 50°C for 3.5 hours to obtain composite porous titanium dioxide; Step 2: Add the composite porous titanium dioxide to ethanol, disperse it evenly at a speed of 4000r / min in an ice bath, then add manganese nitrate tetrahydrate and cerium nitrate hexahydrate and mix them evenly, the mass ratio of the composite porous titanium dioxide, manganese nitrate tetrahydrate and cerium nitrate hexahydrate is 9.5:0.5:0.8, add ammonium hydroxide dropwise until the pH is 9.5, age at 30°C for 12 hours, centrifuge, wash, dry, grind and sieve 75 mesh; obtain a precursor catalyst; Step 3: (1) Place the precursor catalyst in an air atmosphere, set the temperature to 550°C, calcine it once for 3.5 hours, cool it down, and obtain catalyst A; (2) Place catalyst A in a 0.12 mol / L perchloric acid aqueous solution, stir it at 40°C for 7 hours, wash and dry it to obtain activated catalyst A; (3) Place the activated catalyst A in a nitrogen atmosphere, set the temperature to 250°C, heat treat it for 1.5 hours, cool it, and obtain an SCR denitration catalyst.
[0029] Comparative Example 3: Based on Example 1, the modified titanium dioxide was prepared by using the citric acid complexation method instead of the coprecipitation method, and the other processes remained unchanged, specifically: Add citric acid to ethanol, stir for 1.5 hours at 25°C, add n-butyl titanate, manganese nitrate tetrahydrate and cerium nitrate hexahydrate, the mass ratio of n-butyl titanate, manganese nitrate tetrahydrate and cerium nitrate hexahydrate is 11:0.5:0.8, react at 25°C for 4 hours, then age for 12 hours, dry at 78°C for 12 hours, calcine at 550°C for 7 hours, screen with 50 mesh, and obtain SCR denitration catalyst.
[0030] Comparative Example 4: Based on Example 1, the catalyst precursor is directly calcined to obtain an SCR denitration catalyst, and the rest of the process remains unchanged, specifically: Step 1: Preparation of silane coupling agent: 1-pyridinepentenol and mercaptopropyltrimethoxysilane are added to tetrahydrofuran in a molar ratio of 1:1, and azobisisobutyronitrile is added and stirred evenly; click reaction is carried out under ultraviolet light for 3 hours, and the solvent is evaporated to obtain a silane coupling agent; Step 2: Preparation of composite porous titanium dioxide: (1) Add 5.5 parts of titanium oxysulfate to 35 parts of deionized water, add 1.5 parts of ammonia water, age at 25°C for 10 hours, dry, calcine at 550°C for 3.5 hours, grind to obtain porous titanium dioxide; (2) Add 3.5 parts of porous titanium dioxide and 5 parts of diisopropanolamine to 36 parts of 7.5wt% ethylene glycol-ethanol solution, ultrasonically disperse at 50°C for 3.5 hours to obtain primary modified titanium dioxide; (3) Add 3.5 parts of primary modified titanium dioxide and 4.5 parts of silane coupling agent to 35 parts of 32wt% ethanol aqueous solution, add glacial acetic acid and 25wt% ammonia water dropwise at 40°C to adjust the pH to 5.5, then ultrasonically disperse for 1.5 hours, wash, filter and dry to obtain composite porous titanium dioxide; Step 3: Add the composite porous titanium dioxide to ethanol, disperse it evenly at a speed of 4000r / min under an ice bath, then add manganese nitrate tetrahydrate and cerium nitrate hexahydrate and mix them evenly, the mass ratio of the composite porous titanium dioxide, manganese nitrate tetrahydrate and cerium nitrate hexahydrate is 9.5:0.5:0.8, add ammonium hydroxide dropwise until the pH is 9.5, age at 30°C for 12 hours, centrifuge, wash, dry, grind and sieve 75 mesh; obtain a precursor catalyst; Step 4: calcine the precursor catalyst at 550° C. for 5 hours and cool it to obtain an SCR denitration catalyst.
[0031] Testing experiment: The performance of the SCR denitration catalyst prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was tested: (1) Conversion rate test: The SCR denitration catalyst prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was tested at 175°C to study the effect of sulfur dioxide on the SCR denitration catalyst. The conversion rate was tested without introducing sulfur dioxide and after introducing sulfur dioxide for three hours. The test results are shown in Table 1.
[0032] Table 1 Result analysis: According to the data analysis in Table 1, it can be seen that the SCR denitration catalyst of the present invention uses composite porous titanium dioxide as a carrier material and manganese and cerium as active components to synergistically promote the activity of the catalyst and improve the denitration efficiency. Through secondary modification, the problems of poor dispersibility and secondary agglomeration in the preparation of traditional titanium dioxide are solved; and through the processes of primary calcination, acid activation, secondary calcination, etc., the problem of impurities blocking the pore size due to subsequent calcination is solved, the specific surface area is enhanced, the active sites are increased, and the denitration efficiency of the catalyst is further improved.
[0033] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.
Claims
1. A method for preparing a SCR denitration catalyst, characterized in that: The following steps are involved: Step 1: Add the composite porous titanium dioxide to ethanol, disperse it evenly at a speed of 3000-5000 r / min in an ice bath, then add manganese nitrate tetrahydrate and cerium nitrate hexahydrate and mix them evenly, add ammonium hydroxide dropwise until the pH is 9.0-10.0, age it at 20-40° C. for 10-14 hours, centrifuge, wash, dry, grind and sieve it; obtain a precursor catalyst; Step 2: The precursor catalyst is subjected to the steps of primary calcination, acid activation, and secondary calcination in sequence to obtain an SCR denitration catalyst.
2. The method for preparing a SCR denitration catalyst according to claim 1, characterized in that: In the raw materials of the SCR denitration catalyst, the mass ratio of composite porous titanium dioxide, manganese nitrate tetrahydrate and cerium nitrate hexahydrate is 8-11:0.3-0.8:0.
8.
3. The method for preparing a SCR denitration catalyst according to claim 1, characterized in that: The specific steps of step 2 are: (1) placing the precursor catalyst in an air atmosphere, setting the temperature to 500-600° C., calcining for 3-4 hours, cooling down, and obtaining catalyst A; (2) placing catalyst A in a 0.1-0.15 mol / L perchloric acid aqueous solution, stirring at 30-50° C. for 6-8 hours, washing, and drying, and obtaining an activated catalyst A; (3) The activated catalyst A is placed in a nitrogen atmosphere, the temperature is set to 200-300° C. for heat treatment for 1-2 hours, and then cooled to obtain an SCR denitration catalyst.
4. The method for preparing an SCR denitration catalyst according to claim 1, characterized in that: The mesh number of the grinding and sieving is 60 to 90 meshes.
5. The method for preparing a SCR denitration catalyst according to claim 1, characterized in that: The preparation process of the composite porous titanium dioxide is as follows: Step 1: adding titanyl sulfate to deionized water, adding ammonia water, aging at 20-30°C for 8-12 hours, drying, calcining at 500-600°C for 3-4 hours, grinding, and obtaining porous titanium dioxide; Step 2: adding porous titanium dioxide and diisopropanolamine to a 5-10 wt% ethylene glycol-ethanol solution, and ultrasonically dispersing at 45-55° C. for 2-5 hours to obtain primary modified titanium dioxide; Step 3: Add the primary modified titanium dioxide and silane coupling agent to a 30-35wt% ethanol aqueous solution, add glacial acetic acid and 20-30wt% ammonia water dropwise at 30-50°C to adjust the pH to 4.0-7.0, then ultrasonically disperse for 1-2 hours, wash, filter and dry to obtain a composite porous titanium dioxide.
6. The method for preparing a SCR denitration catalyst according to claim 5, characterized in that: The raw materials of the porous titanium dioxide include the following components: 5-6 parts of titanyl sulfate, 30-40 parts of deionized water, and 1-2 parts of ammonia water, by mass.
7. The method for preparing a SCR denitration catalyst according to claim 5, characterized in that: The raw materials of the primary modified titanium dioxide include the following components: 3-4 parts of porous titanium dioxide, 4-6 parts of diisopropanolamine, and 32-40 parts of 5-10 wt % ethylene glycol-ethanol solution, by weight; The raw materials of the composite porous titanium dioxide include the following components: 3-4 parts of primary modified titanium dioxide, 4-5 parts of silane coupling agent, and 30-40 parts of 30-35wt% ethanol aqueous solution, by weight.
8. The method for preparing an SCR denitration catalyst according to claim 5, characterized in that: The preparation method of the silane coupling agent comprises: adding 1-pyridinepentenol and mercaptopropyltrimethoxysilane in a molar ratio of 1:1-1.1 to tetrahydrofuran in sequence, adding azobisisobutyronitrile and stirring evenly; performing a click reaction for 2-4 hours under ultraviolet light, and evaporating the solvent to obtain the silane coupling agent.
9. An SCR denitration catalyst prepared according to the method for preparing an SCR denitration catalyst according to any one of claims 1 to 8.