Preparation method of denitration catalyst for synergistically removing non-methane hydrocarbon

Abstract

The invention provides a preparation method of a denitration catalyst for synergistically removing non-methane hydrocarbon, and belongs to the technical field of air pollution control. The preparation method comprises the following steps: preparing a first catalyst precursor taking a molecular sieve as a carrier; preparing a second catalyst precursor taking titanium oxide as a carrier; and mixing the second catalyst precursor with a binder, coating the surface of the first catalyst precursor with the mixture, and roasting to obtain the catalyst. Two catalyst precursors are respectively prepared through different raw materials and treatment means and are synthesized into the catalyst, so that the catalyst has the characteristics of denitration and synergistic removal of non-methane hydrocarbon in coke oven flue gas, the catalyst can be directly replaced in an existing denitration reactor, a new catalyst reactor does not need to be built, an existing process does not need to be changed, and the cost is low. The method is of great significance in reducing pollution and carbon and reducing the investment and operation cost of enterprises.

Description

Technical Field

[0001] The invention belongs to the technical field of air pollution control, and in particular relates to a method for preparing a denitration catalyst for synergistically removing non-methane total hydrocarbons. Background Art

[0002] Nitrogen oxides (NOx) and non-methane hydrocarbons are important precursors of PM2.5 and O3 atmospheric pollutants. While the coking industry supports the coke-steel-infrastructure industry chain, it also emits a large amount of coke oven flue gas. Coke oven flue gas is an important source of coking pollutants. In addition to SO2 and NOx, it also contains highly toxic VOCs (benzene derivatives, dioxins) and a large number of non-CO2 carbon-containing small molecules with stronger greenhouse effects, such as methane and non-methane hydrocarbons. How to achieve coordinated pollution reduction and carbon reduction of coke oven flue gas and improve air quality and greenhouse effect is of great significance.

[0003] At present, the denitration catalysts on the market are relatively mature and widely used in the power, steel, cement, coking and other industries, and the application effect is good. On the basis of the existing denitration catalyst, the preparation process is modified and optimized to enable it to have denitration and synergistic removal of non-methane total hydrocarbons in coke oven flue gas, which is of extraordinary significance for reducing pollution, reducing carbon emissions and reducing enterprise investment and operating costs. CN10075848A discloses a catalyst for removing non-methane total hydrocarbons from total hydrocarbons, but the catalyst is limited to the use of detection equipment for testing non-methane total hydrocarbons by catalytic oxidation method, and cannot be used for the removal of pollutants in flue gas. CN118477657A discloses a catalyst for integrated treatment of SO2, NOx, and non-methane total hydrocarbons. The dispersion of the catalyst is improved by repeated rolling and grinding, and the technical problem of low catalyst loading in non-methane total hydrocarbon detection equipment is solved. The application scenario and the problem to be solved are to increase the temperature use window of non-methane total hydrocarbon detection equipment and reduce the structure of the equipment. CN113457681A discloses a Co-based catalyst derived from MOFs for catalytic combustion of non-methane total hydrocarbons. The catalyst is limited to detection of non-methane total hydrocarbons in non-methane total hydrocarbon detection equipment and cannot be used for removal of pollutants in flue gas.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a denitrification catalyst for synergistically removing non-methane total hydrocarbons. Two catalyst precursors are prepared respectively by different raw materials and treatment methods, and the catalyst is synthesized from them so that it has the characteristics of denitrification and synergistic removal of non-methane total hydrocarbons in coke oven flue gas. The catalyst can be directly replaced in the existing denitrification reactor without the need to build a new catalyst reactor or change the existing process. This is of great significance for reducing pollution and carbon emissions and reducing the investment and operating costs of enterprises.

[0006] In order to achieve the above objectives, the present invention particularly adopts the following technical solutions:

[0007] The present invention provides a method for preparing a denitration catalyst for collaboratively removing non-methane total hydrocarbons, comprising:

[0008] A first catalyst precursor with a molecular sieve as a carrier is prepared; a second catalyst precursor with a titanium oxide as a carrier is prepared; the second catalyst precursor is mixed with a binder, coated on the surface of the first catalyst precursor, and calcined to obtain the catalyst.

[0009] When preparing the two catalyst precursors, two carrier components are used to give full play to their respective advantages. The strong anti-sulfur performance of titanium dioxide is used to prevent sulfur poisoning of the catalyst; the pore size distribution of the molecular sieve is used to improve the adsorption and capture of non-methane hydrocarbons, which is beneficial to the improvement of the catalyst denitrification efficiency and the oxidation rate of non-methane hydrocarbons.

[0010] Furthermore, the preparation of the first catalyst precursor with molecular sieve as carrier includes: adding manganese salt and cobalt salt into a first dilute acid solution to fully dissolve, then mixing them with the molecular sieve, fully impregnating, granulating and forming, and finally performing a first drying and a first calcination to obtain the first catalyst precursor.

[0011] Optionally, the manganese salt comprises manganese nitrate; optionally, the cobalt salt comprises cobalt nitrate.

[0012] Furthermore, the first dilute acid solution is a 0.15-0.25 mol / L dilute sulfuric acid solution.

[0013] Furthermore, the mass ratio of the manganese salt, the cobalt salt, the first dilute acid solution and the molecular sieve is (1.5-5):(0.5-2):(43-50):100.

[0014] Furthermore, the temperature of the first calcination is 500-600° C., and the time of the first calcination is 4-6 hours.

[0015] Preferably, before adding the manganese salt and the cobalt salt into the first dilute acid solution, the first dilute acid solution is heated to 35-50°C.

[0016] Furthermore, the preparation of the second catalyst precursor with titanium oxide as the carrier includes: adding ammonium salt and molybdenum salt into a second dilute acid solution to fully dissolve, then mixing them with the titanium oxide carrier, fully impregnating, and finally performing a second drying and a second calcination to obtain the second catalyst precursor.

[0017] Optionally, the ammonium salt includes ammonium metavanadate; optionally, the molybdenum salt includes ammonium heptamolybdate; optionally, the titanium oxide includes titanium dioxide.

[0018] Furthermore, the second dilute acid solution is a 0.1-0.2 mol / L dilute sulfuric acid solution.

[0019] The carriers and active components of the first catalyst precursor and the second catalyst precursor are both subjected to sulfation treatment, which can improve the sulfur resistance of the catalyst, effectively avoid catalyst poisoning and deactivation caused by sulfation of the active components of the catalyst, and extend the chemical life of the catalyst.

[0020] Furthermore, the mass ratio of the ammonium salt, the molybdenum salt, the second dilute acid solution and the titanium oxide carrier is (0.5-3):(3-7):(18-20):100.

[0021] Furthermore, the temperature of the second calcination is 450-550° C., and the time of the second calcination is 3-5 hours.

[0022] Preferably, before adding the ammonium salt and the molybdenum salt into the second dilute acid solution, the second dilute acid solution is first heated to 85-95°C.

[0023] Whether in the preparation of the first catalyst precursor or the second catalyst precursor, heating the dilute acid can not only achieve the purpose of acidification, but also improve the acidity of the acid sites of the catalyst active components. At the same time, experiments have found that both the denitration rate and the non-methane total hydrocarbon oxidation rate are improved to a certain extent, especially having a synergistic effect of the two.

[0024] Furthermore, the mass ratio of the first catalyst precursor to the second catalyst precursor is 100:(15-35).

[0025] Furthermore, the calcination temperature is 300-350° C., and the calcination time is 2-3 hours.

[0026] Optionally, the binder includes one or more of silica sol, methyl cellulose or polyvinyl alcohol.

[0027] Preferably, when the binder comprises silica sol, methyl cellulose and polyvinyl alcohol, the mass ratio of the silica sol, methyl cellulose, polyvinyl alcohol to the titanium oxide support is (6-10):(0.5-2):(0.5-2):100.

[0028] Preferably, the particle size of the first catalyst precursor is controlled at 1.5-2.5 mm;

[0029] Preferably, the particle size of the catalyst is controlled at 1.7-3 mm. The first catalyst precursor uses a molecular sieve carrier, which can effectively improve the dispersibility and activity of the active component on the carrier surface. The second catalyst precursor is rolled and coated on the surface of the first catalyst precursor, and the thickness of the second catalyst precursor is strictly controlled, which improves the positive reaction of the catalyst from the perspective of chemical reaction kinetics and reduces the occurrence of catalyst side reactions.

[0030] Compared with the prior art, the present application prepares two catalyst precursors respectively through different raw materials and processing methods. When preparing the two catalyst precursors, heated sulfuric acid is used for acidification, and finally the catalyst is synthesized by coating, and the thickness of the coating layer is specifically controlled. The catalyst of the present application has the characteristics of denitration and synergistic removal of non-methane total hydrocarbons in coke oven flue gas. The catalyst can be directly replaced in the existing denitration reactor without the need to build a new catalyst reactor and change the existing process. It is of great significance for reducing pollution and carbon emissions and reducing the investment and operating costs of enterprises.

[0031] The catalyst provided in the present application has high denitration activity and high non-methane total hydrocarbon oxidation rate. The catalyst has a denitration efficiency of 65-99% and a non-methane total hydrocarbon oxidation rate of 45-95% within a temperature range of 170-420°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 The curves showing the change of the catalyst denitration efficiency and the conversion rate of non-methane total hydrocarbons with temperature in Example 1 of the present invention;

[0034] Figure 2 The curves showing the change of the catalyst denitration efficiency and the conversion rate of non-methane total hydrocarbons with temperature in Example 2 of the present invention;

[0035] Figure 3 The curves showing the change of the catalyst denitration efficiency and the non-methane total hydrocarbon conversion rate with temperature in Example 3 of the present invention;

[0036] Figure 4 The curves showing the change of the catalyst denitration efficiency and the conversion rate of non-methane total hydrocarbons with the temperature of Example 4 of the present invention;

[0037] Figure 5 The curves showing the change of the catalyst denitration efficiency and the conversion rate of non-methane total hydrocarbons with temperature in Example 5 of the present invention;

[0038] Figure 6 The curves showing the change of the catalyst denitration efficiency and the conversion rate of non-methane total hydrocarbons with temperature in Example 6 of the present invention;

[0039] Figure 7 The curves showing the change of the catalyst denitration efficiency and the conversion rate of non-methane total hydrocarbons with the temperature of Example 7 of the present invention;

[0040] Figure 8 The curves showing the change of the catalyst denitration efficiency and the conversion rate of non-methane total hydrocarbons with the temperature of Example 8 of the present invention;

[0041] Fig. 9 The curve showing the change of the catalyst denitration efficiency and the conversion rate of non-methane total hydrocarbons with temperature in Comparative Example 1 of the present invention;

[0042] Fig.10 The curve showing the change of the catalyst denitration efficiency and the non-methane total hydrocarbon conversion rate with temperature in Comparative Example 2 of the present invention;

[0043] Fig.11 The curves showing the change of the catalyst denitration efficiency and the non-methane total hydrocarbon conversion rate with temperature in Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0045] The ratios not given in the examples are all arbitrary ratios, the units of the ratios not given are all mass ratios, and the raw materials are all conventional commercially available products.

[0046] The performance of the catalysts obtained in the following examples and comparative examples was tested under simulated coke oven flue gas conditions. NH3 was used as a reducing agent. The test flue gas conditions were: NO was 150 ppm, SO2 was 30 ppm, O2 was 9.5%, H2O was 8.0%, C2H4 was 50 ppm, C2H6 was 100 ppm, C3H6 was 50 ppm, C3H8 was 50 ppm, C6H6 was 30 ppm, C7H8 was 30 ppm, and the air velocity was 10000 h -1 The denitrification activity and catalytic oxidation activity were evaluated in a fixed bed reactor at a temperature ranging from 150°C to 420°C.

[0047] Example 1

[0048] A preparation method of a denitrification catalyst for synergistically removing non-methane total hydrocarbons: add 22g of 10% dilute sulfuric acid into a beaker of 150mL deionized water and heat to 35°C. Dissolve 12g of cobalt nitrate and 75g of manganese nitrate in the dilute sulfuric acid solution respectively; add the solution into 382g of molecular sieve and stir continuously to fully soak it. After soaking for 12 hours, perform rolling granulation with a particle size of 1.5mm to obtain a first catalyst precursor intermediate for standby use; transfer the first catalyst precursor intermediate to a 75°C forced drying oven and dry it for 12 hours. After drying, move it to a muffle furnace and heat it to 500°C at a heating rate of 3°C / min, keep it warm and roast it for 5 hours to obtain a first catalyst precursor for standby use. Add 2.94g of 10% dilute sulfuric acid to a beaker of 30mL deionized water and heat to 85°C; dissolve 1.5g of ammonium metavanadate and 3.2g of ammonium heptamolybdate in the dilute sulfuric acid solution; add the solution to 55g of nano titanium dioxide and stir continuously to fully soak it. After soaking for 18 hours, the second catalyst precursor intermediate is obtained and set aside; transfer the second catalyst precursor intermediate to a muffle furnace and heat it to 450°C at a heating rate of 3°C / min, keep it warm and roast it for 3 hours, and grind it after cooling to obtain the second catalyst precursor and set aside. Add 16.5g of 20% silica sol, 0.5g of methyl cellulose and 0.5g of polyvinyl alcohol to the second catalyst precursor, stir evenly, and apply the powder to the first catalyst precursor by rolling granulation, and control the particle size to be about 1.8mm and set aside. The spherical particles with a diameter of about 1.8 mm were placed in a muffle furnace, heated to 300°C at a heating rate of 3°C / min, kept warm and calcined for 2.5 hours, and then cooled to obtain the catalyst. The test performance of the catalyst is as follows: Figure 1 shown.

[0049] Example 2

[0050] A preparation method of a denitrification catalyst for synergistically removing non-methane total hydrocarbons: add 22g of 10% dilute sulfuric acid into a beaker of 150mL deionized water and heat to 40°C. Dissolve 20g of cobalt nitrate and 62g of manganese nitrate in the dilute sulfuric acid solution respectively; add the solution into 382g of molecular sieve and stir continuously to fully soak it. After soaking for 14 hours, perform rolling granulation with a particle size of 1.7mm to obtain a first catalyst precursor intermediate for standby use; transfer the first catalyst precursor intermediate to a blast drying oven at 80°C and dry it for 12 hours. After drying, move it to a muffle furnace and heat it to 550°C at a heating rate of 4°C / min, keep it warm and roast it for 4 hours to obtain a first catalyst precursor for standby use. Add 2.94g of 10% dilute sulfuric acid to a beaker of 30mL deionized water and heat to 90°C; dissolve 1.8g of ammonium metavanadate and 4.5g of ammonium heptamolybdate in the dilute sulfuric acid solution; add the solution to 55g of nano titanium dioxide and stir continuously to fully soak it. After soaking for 20 hours, the second catalyst precursor intermediate is obtained and set aside; transfer the second catalyst precursor intermediate to a muffle furnace and heat it to 500°C at a heating rate of 4°C / min, keep it warm and roast it for 3 hours, and grind it after cooling to obtain the second catalyst precursor and set aside. Add 16.5g of 20% silica sol, 0.5g of methyl cellulose and 0.5g of polyvinyl alcohol to the second catalyst precursor, stir evenly, and apply the powder to the first catalyst precursor by rolling granulation, and control the particle size to be about 2.0mm, and set aside. The spherical particles with a diameter of about 2.0 mm were placed in a muffle furnace, heated to 320°C at a heating rate of 4°C / min, kept warm and calcined for 2 hours, and then cooled to obtain the catalyst. The test performance of the catalyst is as follows: Figure 2 shown.

[0051] Example 3

[0052] A preparation method of a denitrification catalyst for synergistically removing non-methane total hydrocarbons: add 29.5g of 10% dilute sulfuric acid into a beaker of 150mL deionized water and heat to 45°C. Dissolve 28g of cobalt nitrate and 56g of manganese nitrate in the dilute sulfuric acid solution; add the solution into 382g of molecular sieve and stir continuously to fully soak it. After soaking for 16 hours, perform rolling granulation with a particle size of 2.0mm to obtain a first catalyst precursor intermediate for standby use; transfer the first catalyst precursor intermediate to a blast drying oven at 85°C and dry it for 12 hours. After drying, move it to a muffle furnace and heat it to 600°C at a heating rate of 3°C / min, keep it warm and roast it for 5 hours to obtain a first catalyst precursor for standby use. Add 4.4g of 10% dilute sulfuric acid to a beaker of 30mL deionized water and heat to 85°C; dissolve 2.1g of ammonium metavanadate and 4.7g of ammonium heptamolybdate in the dilute sulfuric acid solution; add the solution to 55g of nano titanium dioxide and stir continuously to fully soak it. After soaking for 22h, the second catalyst precursor intermediate is obtained and set aside; transfer the second catalyst precursor intermediate to a muffle furnace and heat it to 550°C at a heating rate of 3°C / min, keep it warm and roast it for 4h, and grind it after cooling to obtain the second catalyst precursor and set aside. Add 22g of 20% silica sol, 0.8g of methyl cellulose, and 0.8g of polyvinyl alcohol to the second catalyst precursor, stir evenly, and apply the powder to the first catalyst precursor by rolling granulation, and control the particle size to be about 2.3mm and set aside. The spherical particles with a diameter of about 2.3 mm were placed in a muffle furnace, heated to 350°C at a heating rate of 3°C / min, kept warm and calcined for 3 hours, and then cooled to obtain the catalyst. The test performance of the catalyst is as follows: Figure 3 shown.

[0053] Example 4

[0054] A preparation method of a denitrification catalyst for synergistically removing non-methane total hydrocarbons: add 29.5g of 10% dilute sulfuric acid into a beaker of 150mL deionized water and heat to 45°C. Dissolve 32g of cobalt nitrate and 52g of manganese nitrate in the dilute sulfuric acid solution respectively; add the solution into 382g of molecular sieve and stir continuously to fully soak it. After soaking for 16 hours, perform rolling granulation with a particle size of 2.2mm to obtain a first catalyst precursor intermediate for standby use; transfer the first catalyst precursor intermediate to a blast drying oven at 85°C and dry it for 12 hours. After drying, move it to a muffle furnace and heat it to 600°C at a heating rate of 4°C / min, keep it warm and roast it for 6 hours to obtain a first catalyst precursor for standby use. Add 4.4g of 10% dilute sulfuric acid to a beaker of 30mL deionized water and heat to 85°C; dissolve 2.5g of ammonium metavanadate and 5.5g of ammonium heptamolybdate in the above dilute sulfuric acid solution respectively; add the above solution to 55g of nano titanium dioxide and stir continuously to make it fully soaked. After soaking for 24 hours, the second catalyst precursor intermediate is obtained and set aside; transfer the second catalyst precursor intermediate to a muffle furnace and heat it to 550°C at a heating rate of 4°C / min, keep it warm and roast it for 5 hours, and grind it after cooling to obtain the second catalyst precursor and set aside. Add 22g of 20% silica sol, 0.8g of methyl cellulose and 0.8g of polyvinyl alcohol to the second catalyst precursor, stir evenly, and roll the powder to coat the first catalyst precursor with ball granulation, and control the particle size to be about 2.5mm, and set aside. The spherical particles with a diameter of about 2.5 mm were placed in a muffle furnace, heated to 350°C at a heating rate of 4°C / min, kept warm and calcined for 3 hours, and then cooled to obtain the catalyst. The test performance of the catalyst is as follows: Figure 4 shown.

[0055] Example 5

[0056] A preparation method of a denitrification catalyst for synergistically removing non-methane total hydrocarbons: add 36.7g of 10% dilute sulfuric acid into a beaker of 150mL deionized water and heat to 40°C. Dissolve 26g of cobalt nitrate and 81g of manganese nitrate in the dilute sulfuric acid solution respectively; add the solution into 382g of molecular sieve and stir continuously to fully soak it. After soaking for 14 hours, perform rolling granulation with a particle size of 2.4mm to obtain a first catalyst precursor intermediate for standby use; transfer the first catalyst precursor intermediate to a blast drying oven at 85°C and dry it for 12 hours. After drying, move it to a muffle furnace and heat it to 580°C at a heating rate of 5°C / min, keep it warm and roast it for 6 hours to obtain a first catalyst precursor for standby use. Add 2.94g of 10% dilute sulfuric acid to a beaker of 30mL deionized water and heat to 85°C; dissolve 1.2g of ammonium metavanadate and 2.8g of ammonium heptamolybdate in the dilute sulfuric acid solution; add the solution to 55g of nano titanium dioxide and stir continuously to fully soak it. After soaking for 24 hours, the second catalyst precursor intermediate is obtained and set aside; transfer the second catalyst precursor intermediate to a muffle furnace and heat it to 480°C at a heating rate of 5°C / min, keep it warm and roast it for 3.5 hours, and grind it after cooling to obtain the second catalyst precursor and set aside. Add 17.5g of 20% silica sol, 0.6g of methyl cellulose and 0.6g of polyvinyl alcohol to the second catalyst precursor, stir evenly, and apply the powder to the first catalyst precursor by rolling granulation, and control the particle size to be about 2.7mm and set aside. The spherical particles with a diameter of about 2.5 mm were placed in a muffle furnace, heated to 350°C at a heating rate of 5°C / min, kept warm and calcined for 3 hours, and then cooled to obtain the catalyst. The test performance of the catalyst is as follows: Figure 5 shown.

[0057] Example 6

[0058] A preparation method of a denitrification catalyst for synergistically removing non-methane total hydrocarbons: add 36.7g of 10% dilute sulfuric acid into a beaker of 150mL deionized water and heat to 40°C. Dissolve 19g of cobalt nitrate and 84g of manganese nitrate in the dilute sulfuric acid solution respectively; add the solution into 382g of molecular sieve and stir continuously to fully soak it. After soaking for 14 hours, perform rolling granulation with a particle size of 2.5mm to obtain a first catalyst precursor intermediate for standby use; transfer the first catalyst precursor intermediate to a blast drying oven at 85°C and dry it for 12 hours. After drying, move it to a muffle furnace and heat it to 580°C at a heating rate of 3°C / min, keep it warm and roast it for 6 hours to obtain a first catalyst precursor for standby use. Add 2.94g of 10% dilute sulfuric acid to a beaker of 30mL deionized water and heat to 85°C; dissolve 1.0g of ammonium metavanadate and 2.5g of ammonium heptamolybdate in the dilute sulfuric acid solution; add the solution to 55g of nano titanium dioxide and stir continuously to fully soak it. After soaking for 24 hours, the second catalyst precursor intermediate is obtained and set aside; transfer the second catalyst precursor intermediate to a muffle furnace and heat it to 480°C at a heating rate of 3°C / min, keep it warm and roast it for 3.5 hours, and grind it after cooling to obtain the second catalyst precursor and set aside. Add 17.5g of 20% silica sol, 0.6g of methyl cellulose and 0.6g of polyvinyl alcohol to the second catalyst precursor, stir evenly, and apply the powder to the first catalyst precursor by rolling granulation, and control the particle size to be about 3.0mm for set aside. The spherical particles with a diameter of about 3.0 mm were placed in a muffle furnace, heated to 350°C at a heating rate of 3°C / min, kept warm and calcined for 3 hours, and then cooled to obtain the catalyst. The test performance of the catalyst is as follows: Figure 6 shown.

[0059] Example 7

[0060] A preparation method of a denitrification catalyst for synergistically removing non-methane total hydrocarbons: add 20g of 10% dilute sulfuric acid into a beaker of 150mL deionized water and heat to 35°C. Dissolve 16g of cobalt nitrate and 48g of manganese nitrate in the dilute sulfuric acid solution respectively; add the solution into 382g of molecular sieve and stir continuously to fully soak it. After soaking for 16 hours, perform rolling granulation with a particle size of 1.6mm to obtain a first catalyst precursor intermediate for standby use; transfer the first catalyst precursor intermediate to a 75°C forced drying oven and dry it for 12 hours. After drying, move it to a muffle furnace and heat it to 550°C at a heating rate of 3°C / min, keep it warm and roast it for 6 hours to obtain a first catalyst precursor for standby use. Add 3.67g of 10% dilute sulfuric acid to a beaker of 30mL deionized water and heat to 90°C; dissolve 2.3g of ammonium metavanadate and 4.8g of ammonium heptamolybdate in the dilute sulfuric acid solution; add the solution to 55g of nano titanium dioxide and stir continuously to fully soak it. After soaking for 24 hours, the second catalyst precursor intermediate is obtained and set aside; transfer the second catalyst precursor intermediate to a muffle furnace and heat it to 500°C at a heating rate of 3°C / min, keep it warm and roast it for 4 hours, and grind it after cooling to obtain the second catalyst precursor and set aside. Add 16.5g of 20% silica sol, 0.7g of methyl cellulose and 0.7g of polyvinyl alcohol to the second catalyst precursor, stir evenly, and apply the powder to the first catalyst precursor by rolling granulation, and control the particle size to be about 2.0mm for set aside. The spherical particles with a diameter of about 2.0 mm were placed in a muffle furnace, heated to 330°C at a heating rate of 3°C / min, kept warm and calcined for 3 hours, and then cooled to obtain the catalyst. The test performance of the catalyst is as follows: Figure 7 shown.

[0061] Example 8

[0062] A preparation method of a denitrification catalyst for synergistically removing non-methane total hydrocarbons: add 18g of 10% dilute sulfuric acid into a beaker of 150mL deionized water and heat to 35°C. Dissolve 22g of cobalt nitrate and 42g of manganese nitrate in the dilute sulfuric acid solution respectively; add the solution into 382g of molecular sieve and stir continuously to fully soak it. After soaking for 16 hours, perform rolling granulation with a particle size of 1.8mm to obtain a first catalyst precursor intermediate for standby use; transfer the first catalyst precursor intermediate to a blast drying oven at 80°C and dry it for 12 hours. After drying, move it to a muffle furnace and heat it to 500°C at a heating rate of 5°C / min, keep it warm and roast it for 6 hours to obtain a first catalyst precursor for standby use. Add 3.67g of 10% dilute sulfuric acid to a beaker of 30mL deionized water and heat to 85°C; dissolve 0.7g of ammonium metavanadate and 2.2g of ammonium heptamolybdate in the above dilute sulfuric acid solution respectively; add the above solution to 55g of nano titanium dioxide and stir continuously to make it fully soaked. After soaking for 24 hours, the second catalyst precursor intermediate is obtained and set aside; transfer the second catalyst precursor intermediate to a muffle furnace and heat it to 550°C at a heating rate of 5°C / min, keep it warm and roast it for 3 hours, and grind it after cooling to obtain the second catalyst precursor and set aside. Add 16.5g of 20% silica sol, 0.5g of methyl cellulose and 0.5g of polyvinyl alcohol to catalyst B part, stir evenly, and roll the powder to coat the first catalyst precursor with ball granulation, and control the particle size to be about 2.3mm, and set aside. The spherical particles with a diameter of about 2.5 mm were placed in a muffle furnace, heated to 350°C at a heating rate of 5°C / min, kept warm and calcined for 3 hours, and then cooled to obtain the catalyst. The test performance of the catalyst is as follows: Figure 8 shown.

[0063] Comparative Example 1

[0064] The difference compared with Example 7 is that when preparing the second catalyst precursor, the dilute sulfuric acid is not heated after being prepared, and the test performance of the obtained catalyst is as follows: Fig. 9 shown.

[0065] Comparative Example 2

[0066] The difference compared with Example 7 is that when preparing the first catalyst precursor and the second catalyst precursor, the dilute sulfuric acid is not heated after being prepared. The test performance of the obtained catalyst is as follows: Fig.10 shown.

[0067] Comparative Example 3

[0068] The difference compared with Example 7 is that the binder is 0.7 g of polyvinyl alcohol, and 16.5 g of 20% silica sol and 0.7 g of methyl cellulose are not added. The test performance of the obtained catalyst is as follows: Fig.11 shown.

[0069] Combination Figure 1-8 It can be seen that the catalyst provided by the present invention has a denitration efficiency of 65-99% in the temperature range of 170-420°C, and a non-methane total hydrocarbon oxidation rate of 45-95%. It has good denitration efficiency and non-methane total hydrocarbon oxidation rate, and good synergy.

[0070] Combination Fig. 9 and Figure 7 It can be seen that compared with Example 7, since the dilute sulfuric acid was not heated during the preparation of the second catalyst precursor, the denitration performance declined seriously, and the conversion rate of total hydrocarbons, especially benzene, decreased significantly.

[0071] Combination Fig.10 and Figure 7 It can be seen that compared with Example 7, since the temperature of the dilute sulfuric acid was not raised twice, the denitrification performance and the total hydrocarbon conversion rate were greatly reduced. At the same time, the synergy between the two also decreased significantly.

[0072] Combination Fig.11 and Figure 7 It can be seen that compared with Example 7, due to the use of a single organic binder, the catalytic performance of denitration and total hydrocarbons in Comparative Example 3 is reduced, especially in the high temperature section. However, the present application uses a combination of an inorganic binder, silica sol, and an organic binder, which effectively improves the mechanical strength and wear resistance of the catalyst, facilitates catalyst molding, and plays a good pore-forming role, thereby improving the chemical properties of the catalyst.

[0073] Please note that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. The above embodiments only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all belong to the scope of protection of the present application. Therefore, the scope of protection of the patent in this application shall be based on the attached claims.

Claims

1. A method for preparing a denitration catalyst for synergistically removing non-methane total hydrocarbons, characterized in that: include: preparing a first catalyst precursor with a molecular sieve as a carrier; preparing a second catalyst precursor with titanium oxide as a carrier; The second catalyst precursor is mixed with a binder, coated on the surface of the first catalyst precursor, and calcined to obtain the catalyst.

2. The preparation method according to claim 1, characterized in that: The preparation of the first catalyst precursor with molecular sieve as carrier includes: adding manganese salt and cobalt salt into a first dilute acid solution and fully dissolving them, then mixing them with the molecular sieve, fully impregnating them, granulating them, and finally performing a first drying and a first calcination to obtain the first catalyst precursor.

3. The preparation method according to claim 2, characterized in that: The manganese salt includes manganese nitrate; and / or, the cobalt salt comprises cobalt nitrate; And / or, the first dilute acid solution is a 0.15-0.25 mol / L dilute sulfuric acid solution; And / or, the mass ratio of the manganese salt, the cobalt salt, the first dilute acid solution and the molecular sieve is (1.5-5):(0.5-2):(43-50):100; And / or, the temperature of the first calcination is 500-600° C., and the time of the first calcination is 4-6 hours.

4. The preparation method according to claim 2 or 3, characterized in that: Before adding the manganese salt and the cobalt salt into the first dilute acid solution, the first dilute acid solution is heated to 35-50°C.

5. The preparation method according to claim 1, characterized in that: The preparation of the second catalyst precursor with titanium oxide as the carrier comprises: adding ammonium salt and molybdenum salt into a second dilute acid solution and fully dissolving them, then mixing them with the titanium oxide carrier, fully impregnating them, and finally performing a second drying and a second calcination to obtain the second catalyst precursor.

6. The preparation method according to claim 5, characterized in that: The ammonium salt includes ammonium metavanadate; and / or, the molybdenum salt comprises ammonium heptamolybdate; and / or, the titanium oxide comprises titanium dioxide; And / or, the second dilute acid solution is a 0.1-0.2 mol / L dilute sulfuric acid solution; And / or, the mass ratio of the ammonium salt, the molybdenum salt, the second dilute acid solution and the titanium oxide support is (0.5-3):(3-7):(18-20):100; And / or, the temperature of the second calcination is 450-550° C., and the time of the second calcination is 3-5 hours.

7. The preparation method according to claim 5 or 6, characterized in that: Before adding the ammonium salt and the molybdenum salt into the second dilute acid solution, the second dilute acid solution is first heated to 85-95°C.

8. The preparation method according to claim 1, characterized in that: The mass ratio of the first catalyst precursor to the second catalyst precursor is 100:(15-35).

9. The preparation method according to claim 1, characterized in that: The calcination temperature is 300-350°C, and the calcination time is 2-3h; and / or, the binder comprises one or more of silica sol, methyl cellulose or polyvinyl alcohol; Preferably, when the binder comprises silica sol, methyl cellulose and polyvinyl alcohol, the mass ratio of the silica sol, methyl cellulose, polyvinyl alcohol to the titanium oxide support is (6-10):(0.5-2):(0.5-2):

100.

10. The preparation method according to claim 1, characterized in that: The particle size of the first catalyst precursor is controlled to be 1.5-2.5 mm; The particle size of the catalyst is controlled at 1.7-3 mm.

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