Bifunctional catalyst composition for removing NOx and CVOCs in flue gas as well as preparation method and application of bifunctional catalyst composition

Abstract

The invention discloses a bifunctional catalyst composition for removing NOx and CVOCs in flue gas as well as a preparation method and application of the bifunctional catalyst composition, and the bifunctional catalyst composition is prepared from the following components in percentage by weight of the composition: 5-15 wt% of CeWxMnyTizO3, 10-20 wt% of Fe [delta] Cu [1]-[delta] Co2O4, 60-80 wt% of nano TiO2 and 2-7 wt% of a pore-enlarging agent, the prepared bifunctional catalyst composition can be used for completely converting CVOCs into CO2, CO, H2O and HCl at medium and low reaction temperatures; nOx can be catalytically converted into N2 by utilizing CO generated in the catalytic oxidation process of CVOCs and additionally sprayed NH3, so that the emission of NOx in flue gas is reduced; not only is the CO emission reduced, but also the ammonia spraying amount in the denitration process is reduced.

Description

Technical Field

[0001] The present invention relates to the field of pollution control, and in particular to a dual-function catalyst composition for removing NOx and CVOCs from flue gas, and a preparation method and application thereof. Background Art

[0002] Chlorohydrocarbons are chlorine-containing compounds formed by replacing hydrogen atoms in hydrocarbons with chlorine atoms. Chlorohydrocarbons are widely used as solvents due to their excellent stability and solubility. However, their volatility leads to the presence of chlorinated volatile organic compounds (CVOCs) in many industrial exhaust gases. CVOCs can also be present in the flue gases of coal-fired boilers and the combustion of chlorinated waste. Nitrogen oxides (NOx) and volatile organic compounds (VOCs) are considered common precursors of oxygen (O3) and particulate matter (PM2.5), making them major atmospheric pollutants. CVOCs are also considered precursors of dioxins, making them even more hazardous. Catalytic combustion is one of the most effective methods for controlling emissions of CVOCs and other pollutants, including NOx. The operating temperature for CVOC catalytic combustion is generally between 200 and 450°C, making it the most widely used technology for treating and controlling CVOCs over a wide concentration range. Conventional NOx selective catalytic reduction (SCR) processes operate within this temperature range. Simultaneously removing NOx and VOCs in a single reactor using a dual-function denitrification catalyst is the most cost-effective approach.

[0003] Patents for the simultaneous removal of NOx and VOCs are currently available. For example, Chinese patent document CN112657489A discloses a modified honeycomb monolithic catalyst for the simultaneous removal of organic waste gas and NOx from coal-fired flue gas, as well as its preparation method and application. The modified honeycomb monolithic catalyst and its preparation method comprise first dissolving an X precursor ammonium molybdate, copper nitrate, iron nitrate, cerium nitrate or cobalt nitrate, a V precursor ammonium tungstate, and a W precursor ammonium tungstate in hot water, adding an additive and a carrier silica sol, pseudo-boehmite or hydroxycellulose to obtain a stable slurry, then immersing a nitric acid-treated cordierite honeycomb ceramic in the slurry and calcining it to obtain a modified honeycomb monolithic catalyst for the simultaneous purification of VOCs and NOx from coal-fired flue gas. The addition amounts of each component satisfy the following requirements: the addition amount of molybdenum, copper, iron, cerium or cobalt is 1-10 wt %, the addition amount of vanadium is 0.5-10 wt %, and the addition amount of tungsten is 1-10 wt %.

[0004] Chinese patent document CN114768794A discloses a composite manganese oxide catalyst for the simultaneous removal of VOCs and NOx from medium- and low-temperature flue gas, as well as its preparation method and application. The method comprises: (1) adding an active metal source to deionized water and stirring uniformly to obtain a precursor solution, wherein the active metal source comprises at least one of Fe, Cu, Ce, and Ni; (2) rapidly adding potassium permanganate to the precursor solution and stirring until completely dissolved, transferring the resulting solution to a reactor and reacting under a certain temperature and autogenous pressure; and (3) washing the resulting precipitate with deionized water and drying to obtain the composite manganese oxide catalyst for the simultaneous removal of VOCs and NOx from medium- and low-temperature flue gas.

[0005] Chinese patent document CN112755991A discloses a method for preparing a modified monolithic catalyst for the synergistic removal of organic waste gas and NOx from coal-fired flue gas, characterized in that a precursor formula solution prepared from a metal or precious metal precursor and an additive is composited on a vanadium-titanium material by immersion, and finally dried, aged, and calcined to obtain a full-size monolithic catalyst; the metal includes copper, iron, vanadium, tungsten, molybdenum or titanium; the precious metal includes platinum, palladium, rhodium or ruthenium.

[0006] Yu Yulei et al. (2021) "Study on the reaction mechanism of CeWOx catalyst for synergistic removal of nitrogen oxides and chlorinated aromatic compounds" (Journal of Environmental Sciences, 2022, 42(2): 351-365) disclosed the research status of multiple research institutions at home and abroad on the simultaneous removal of NOx and CVOCs.

[0007] The catalysts disclosed in the above-mentioned patent documents can achieve simultaneous removal of VOCs and NOx within a certain temperature range, but they have poor low-temperature activity, especially poor stability under complex flue gas conditions. The two removal processes inhibit each other, making it difficult to ensure that VOCs and NOx meet emission standards at the same time. They also have problems such as low efficiency in treating CVOCs, high energy consumption, and easy generation of secondary pollutants. Summary of the Invention

[0008] In order to address the deficiencies in the prior art, the present invention aims to provide a bifunctional catalyst composition for removing NOx and CVOCs from flue gas, as well as its preparation method and application. The bifunctional catalyst can completely convert CVOCs into CO2, CO, H2O and HCl at medium and low temperature reaction temperatures; utilizes CO generated during the catalytic oxidation of CVOCs and externally injected NH3 to catalytically convert NOx into N2, thereby reducing NOx emissions in flue gas; and catalyzes CO to participate in the reduction reaction of NOx, thereby reducing CO emissions and reducing the amount of ammonia injected during the denitrification process.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A dual-function catalyst composition for removing NOx and CVOCs from flue gas, comprising the following components based on the weight of the composition: 5-15 wt% CeW x Mn y Ti z O3, 10-20wt% Fe δ Cu 1-δ Co2O4, 60-80wt% nano-TiO2, 2-7wt% pore expanding agent.

[0011] Preferably, the composition is made of the following components: 8-12 wt% CeW x Mn y Ti z O3, 12-18 wt% Fe δ Cu 1-δ Co2O4, 65-75wt% nano-TiO2, 3-6wt% pore expanding agent.

[0012] Preferably, the CeW x Mn y Ti z In O3, x=0~0.9, z=0~0.6, y≤1-(x+z).

[0013] Preferably, the Fe δ Cu 1-δ In Co2O4, δ = 0.1 ~ 0.9.

[0014] Preferably, the pore-enlarging agent is corn starch and / or carboxymethyl cellulose.

[0015] The present invention also claims a method for preparing the catalyst composition, comprising the following steps:

[0016] (1) Cerium salt, tungstate, manganese salt and titanium salt are dissolved to obtain a mixed solution 1, and the mixed solution 1 is added dropwise to an ammonia solution. After the addition is complete, stirring is continued. The product is cooled, filtered, washed until neutral, and then dried and calcined to obtain CeW x Mn y Ti z O3;

[0017] (2) Dissolve the iron salt, copper salt and cobalt salt to obtain a mixed solution 2, add the mixed solution 2 dropwise to the sodium hydroxide-sodium carbonate mixed solution, continue stirring after the addition is complete, cool the product, filter it, wash it until it is neutral, then dry it and roast it to obtain Fe δ Cu 1-δ Co2O4;

[0018] (3) CeW x Mn y Tiz O3 and Fe δ Cu 1-δ Co2O4 is added to distilled water and stirred once, then nano-TiO2 is added and stirred twice, and then a pore-enlarging agent is added and stirred three times to obtain a viscous slurry. The product is dried, roasted, crushed and sieved to obtain a catalyst composition.

[0019] Preferably, in step (1), the temperature of the mixed solution 1 is 40-55° C., the dropwise addition time is 0.5-2.0 h, the solution pH is controlled at 8-10, and the stirring time is 10-18 h.

[0020] Preferably, in step (1), the drying temperature is 120-150° C., and the calcination condition is 550-650° C. for 4-10 hours.

[0021] Preferably, in step (2), the dropping time is 0.5 to 1 h, the temperature during the dropping is 70 to 85° C., the pH value of the solution is controlled at 8 to 10, and the stirring time is 12 to 20 h.

[0022] Preferably, in step (2), the drying temperature is 120-150° C., and the calcination condition is 650-750° C. for 6-12 hours.

[0023] Preferably, in step (2), the concentration of sodium hydroxide in the sodium hydroxide-sodium carbonate mixture is 0.1-0.3 mol / L, and the concentration of sodium carbonate is 0.15-0.35 mol / L.

[0024] Preferably, in step (3), the temperature during the first stirring is 50-70°C, the second stirring time is 3-5 hours, and the third stirring condition is stirring at 65-85°C for 4-8 hours.

[0025] Preferably, in step (3), the drying temperature is 120-150° C., the roasting conditions are 500-600° C. for 6-12 hours, and the product is sieved through a 40-60 mesh sieve.

[0026] The present invention also claims a use of the catalyst composition in removing NOx and CVOCs from flue gas.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention provides a dual-function catalyst composition for removing NOx and CVOCs from flue gas, wherein CeW x Mn y Ti z O3 and Fe δ Cu 1-δ Co2O4 is a dual active component. At low and medium reaction temperatures, CeW x Mny Ti z O3 can reduce the activation energy of CVOCs catalytic conversion reaction, which is beneficial to the conversion of CVOCs into CO2, CO, H2O and HCl; CeW x Mn y Ti z O3 and Fe δ Cu 1-δ The interaction of Co2O4 can not only serve as a catalyst for the catalytic reduction of NOx by NH3, but also promote the catalytic reduction of NOx by CO generated by the catalytic decomposition of CVOCs, catalyzing CO to participate in the reduction reaction of NOx, thereby reducing CO emissions and lowering the amount of ammonia injection in the denitrification process; TiO2, as a carrier, improves the hydrothermal stability and strength of the bifunctional catalyst composition; the pore expander can increase the pore size and pore volume of the bifunctional catalyst composition, which is beneficial to the diffusion of reactant molecules into the interior of the catalyst composition, thereby improving the catalytic conversion rate of denitrification and CVOCs. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. Of course, the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0030] Unless otherwise specified, the chemical reagents and materials in the present invention are purchased from commercial sources or synthesized from commercially purchased raw materials.

[0031] The present invention provides a bifunctional catalyst composition for removing NOx and CVOCs from flue gas, which is made of the following components by weight:

[0032] 5~15wt%CeW x Mn y Ti z O3 can be 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, preferably 8-12wt%;

[0033] 10~20wt%Fe δ Cu 1-δ Co2O4 can be 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, preferably 12-18wt%;

[0034] 60-80wt% nano-TiO2, which can be 60wt%, 65wt%, 70wt%, 75wt%, 80wt%, preferably 65-75wt%;

[0035] 2-7 wt% of the pore-enlarging agent can be 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, preferably 3-6 wt%.

[0036] Specifically, the CeW x Mn y Ti z In O3, x=0~0.9, x can be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9; z=0~0.6, z can be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6; y≤1-(x+z).

[0037] Specifically, the Fe δ Cu 1-δ In Co2O4, δ = 0.1 to 0.9, and δ can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9;

[0038] Specifically, the pore-enlarging agent is corn starch and / or carboxymethyl cellulose.

[0039] The present invention also claims a method for preparing the catalyst composition, comprising the following steps:

[0040] (1) Cerium salt, tungstate, manganese salt and titanium salt are dissolved to obtain a mixed solution 1, and the mixed solution 1 is added dropwise to an ammonia solution. After the addition is complete, stirring is continued. The product is cooled, filtered, washed until neutral, and then dried and calcined to obtain CeW x Mn y Ti z O3;

[0041] (2) Dissolve the iron salt, copper salt and cobalt salt to obtain a mixed solution 2, add the mixed solution 2 dropwise to the sodium hydroxide-sodium carbonate mixed solution, continue stirring after the addition is complete, cool the product, filter it, wash it until it is neutral, then dry it and roast it to obtain Fe δ Cu 1-δ Co2O4;

[0042] (3) CeW x Mn y Ti z O3 and Fe δ Cu 1-δ Co2O4 is added to distilled water and stirred once, then nano-TiO2 is added and stirred twice, and then a pore-enlarging agent is added and stirred three times to obtain a viscous slurry. The product is dried, roasted, crushed and sieved to obtain a catalyst composition.

[0043] Specifically, in step (1), the temperature of the mixed solution 1 is 40-55°C, which can be 40°C, 45°C, 50°C, or 55°C; the dropwise addition time is 0.5-2.0h, which can be 0.5h, 1h, 1.5h, or 2h; the pH of the solution is controlled at 8-10, which can be 8, 8.5, 9, 9.5, or 10; and the stirring time is 10-18h, which can be 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, or 18h.

[0044] Specifically, in step (1), the drying temperature is 120-150°C, and can be 120°C, 130°C, 140°C, or 150°C; the calcination conditions are calcination at 550-650°C for 4-10h, and the calcination temperature can be 550°C, 600°C, or 650°C, and the calcination time can be 4h, 5h, 6h, 7h, 8h, 9h, or 10h.

[0045] Specifically, in step (2), the dropwise addition time is 0.5 to 1 h, which may be 0.5 h or 1 h; the temperature during the dropwise addition is 70 to 85 ° C, which may be 70 ° C, 75 ° C, 80 ° C, or 85 ° C; the pH value of the solution is controlled at 8 to 10, which may be 8, 9, or 10; the stirring time is 12 to 20 h, which may be 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, or 20 h.

[0046] Specifically, in step (2), the drying temperature is 120-150°C, which can be 120°C, 130°C, 140°C, or 150°C; the calcination condition is 650-750°C for 6-12h, and the calcination time can be 650°C, 700°C, or 750°C, and the calcination time is 6h, 7h, 8h, 9h, 10h, 11h, or 12h.

[0047] Specifically, in step (2), the concentration of sodium hydroxide in the sodium hydroxide-sodium carbonate mixture is 0.1-0.3 mol / L, and can be 0.1 mol / L, 0.2 mol / L, or 0.3 mol / L; the concentration of sodium carbonate is 0.15-0.35 mol / L, and can be 0.15 mol / L, 0.25 mol / L, or 0.35 mol / L.

[0048] Specifically, in step (3), the temperature during the first stirring is 50-70°C, which can be 50°C, 55°C, 60°C, 65°C, or 70°C; the second stirring time is 3-5h, which can be 3h, 4h, or 5h; the third stirring condition is stirring at 65-85°C for 4-8h, the stirring temperature can be 65°C, 70°C, 75°C, 80°C, or 85°C, and the stirring time can be 3h, 4h, 5h, 6h, 7h, or 8h.

[0049] Specifically, in step (3), the drying temperature is 120-150°C, and can be 120°C, 130°C, 140°C, or 150°C; the roasting conditions are 500-600°C for 6-12h, the roasting temperature can be 500°C, 550°C, or 600°C, and the roasting time can be 6h, 7h, 8h, 9h, 10h, 11h, or 12h; and the product is sieved through a 40-60 mesh sieve.

[0050] The present invention also claims a use of the catalyst composition in removing NOx and CVOCs from flue gas.

[0051] The present invention will be further described below with reference to specific examples.

[0052] Example 1

[0053] A method for preparing a bifunctional catalyst composition for removing NOx and CVOCs from flue gas comprises the following steps:

[0054] (1) 72.2g Ce(NO3)3·6H2O (content 98.0%), 20.6g (NH4)6H2W 12 O 40 ·4H2O (99.9%), 16.8g Mn(NO3)2·4H2O (97.5%) and 3.1g TiCl4 (99.5%) were added to 200g 50℃ distilled water and stirred to obtain a mixed solution 1, which was slowly added dropwise to a 5vol% ammonia solution for 2.0h. The pH value of the solution was controlled at 10. After the addition was completed, stirring was continued for 12h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 120℃, and calcined at 580℃ for 8h to obtain CeW 0.5 Mn 0.4 Ti 0.1 O3;

[0055] (2) 50.9 g Fe(NO3)3·9H2O (content 98.5%), 25.1 g Cu(NO3)2·6H2O (98.0%), and 121.8 g Co(NO3)2·6H2O (99.0%) were added to 250 g of 75°C distilled water and stirred to obtain a mixed solution II. The mixed solution II was slowly added dropwise to a sodium hydroxide-sodium carbonate mixed solution (sodium hydroxide concentration was 0.2 mol / L, sodium carbonate concentration was 0.25 mol / L) for 1.0 h. The pH value of the solution was controlled at 10. After the addition was completed, stirring was continued for 16 h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 120°C, and calcined at 670°C for 8 h to obtain Fe 0.6 Cu o.4 Co2O4;

[0056] (3) 10.0 g of the ground CeW prepared in step (1) was added 0.5 Mn 0.4 Ti 0.1 O3 and 15.0 g of the ground Fe prepared in step (2) 0.6 Cu o.4 Co2O4 was added to 300g of distilled water and stirred at 60°C. Then, 75.0g of nano-TiO2 was added to a beaker in batches and vigorously stirred for 4h. Then, 5.0g of corn starch was added and stirred at 75°C for 8h to obtain a viscous slurry. The product was dried at 120°C, calcined at 500°C for 10h, crushed, and passed through a 40-60 mesh sieve to obtain a bifunctional catalyst composition.

[0057] Example 2

[0058] A method for preparing a bifunctional catalyst composition for removing NOx and CVOCs from flue gas comprises the following steps:

[0059] (1) 75.7g Ce(NO3)3·6H2O (content 98.0%), 17.3g (NH4)6H2W 12 O 40 ·4H2O (99.9%), 13.2g Mn(NO3)2·4H2O (97.5%) and 9.8g TiCl4 (99.5%) were added to 200g 50℃ distilled water and stirred to obtain a mixed solution 1, which was slowly added dropwise to 5vol% ammonia solution for 1.5h. The pH value of the solution was controlled at 9. After the addition was completed, stirring was continued for 10h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 130℃, and calcined at 600℃ for 7h to obtain CeW 0.4 Mn 0.3 Ti 0.3 O3;

[0060] (2) 33.8 g of Fe(NO3)3·9H2O (content 98.5%), 37.4 g of Cu(NO3)2·6H2O (98.0%), and 121.0 g of Co(NO3)2·6H2O (99.0%) were added to 250 g of 75°C distilled water and stirred to obtain a mixed solution II. The mixed solution II was slowly added dropwise to a sodium hydroxide-sodium carbonate mixed solution (sodium hydroxide concentration was 0.2 mol / L, sodium carbonate concentration was 0.25 mol / L) for 1.0 h. The pH value of the solution was controlled at 10. After the addition was completed, stirring was continued for 14 h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 130°C, and calcined at 700°C for 8 h to obtain Fe 0.4 Cu 0.6 Co2O4;

[0061] (3) 8.0 g of the ground CeW prepared in step (1) was added 0.4 Mn 0.3 Ti 0.3 O3 and 18.0 g of the ground Fe prepared in step (2) 0.4 Cu 0.6 Co2O4 was added to 300g of distilled water and stirred at 60°C. Then, 69.0g of nano-TiO2 was added to the beaker in batches and stirred vigorously for 5h. Then, 5.0g of carboxymethyl cellulose was added and stirred at 75°C for 7h to obtain a viscous slurry. The product was dried at 130°C, calcined at 550°C for 8h, crushed, and passed through a 40-60 mesh sieve to obtain a bifunctional catalyst composition.

[0062] Example 3

[0063] A method for preparing a bifunctional catalyst composition for removing NOx and CVOCs from flue gas comprises the following steps:

[0064] (1) 83.5g Ce(NO3)3·6H2O (content 98.0%), 9.5g (NH4)6H2W 12 O 40 ·4H2O (99.9%), 19.3g Mn(NO3)2·4H2O (97.5%) and 14.3g TiCl4 (99.5%) were added to 200g 50℃ distilled water and stirred to obtain a mixed solution 1, which was slowly added dropwise to a 5vol% ammonia solution for 2.0h. The pH value of the solution was controlled at 10. After the addition was completed, stirring was continued for 12h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 120℃, and calcined at 600℃ for 7h to obtain CeW 0.2 Mn 0.4 Ti 0.4 O3;

[0065] (2) 16.8 g of Fe(NO3)3·9H2O (content 98.5%), 49.6 g of Cu(NO3)2·6H2O (98.0%), and 120.3 g of Co(NO3)2·6H2O (99.0%) were added to 250 g of 75°C distilled water and stirred to obtain a mixed solution II. The mixed solution II was slowly added dropwise to a sodium hydroxide-sodium carbonate mixed solution (sodium hydroxide concentration was 0.2 mol / L, sodium carbonate concentration was 0.25 mol / L) for 1.0 h. The pH value of the solution was controlled at 8. After the addition was completed, stirring was continued for 18 h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 140°C, and calcined at 700°C for 7 h to obtain Fe 0.2 Cu 0.8 Co2O4;

[0066] (3) 12.0 g of the ground CeW prepared in step (1) was added 0.2 Mn 0.4 Ti 0.4 O3 and 12.0 g of the ground Fe prepared in step (2) 0.2 Cu 0.8 Co2O4 was added to 300g of distilled water and stirred at 60°C. Then 73.0g of nano-TiO2 was added to a beaker in batches and stirred vigorously for 5h. Then 3.0g of corn starch was added and stirred at 75°C for 7h to obtain a viscous slurry. The product was dried at 140°C, calcined at 550°C for 12h, crushed, and passed through a 40-60 mesh sieve to obtain a bifunctional catalyst composition.

[0067] Example 4

[0068] A method for preparing a bifunctional catalyst composition for removing NOx and CVOCs from flue gas comprises the following steps:

[0069] (1) 66.7 g Ce(NO3)3·6H2O (content 98.0%), 26.7 g (NH4)6H2W 12 O 40 ·4H2O (99.9%), 3.9g Mn(NO3)2·4H2O (97.5%) and 5.8g TiCl4 (99.5%) were added to 200g 50℃ distilled water and stirred to obtain a mixed solution 1, which was slowly added dropwise to 5vol% ammonia solution for 2.0h. The pH value of the solution was controlled at 10. After the addition was completed, stirring was continued for 12h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 130℃, and calcined at 600℃ for 8h to obtain CeW 0.7 Mn 0.1 Ti 0.2 O3.

[0070] (2) 68.9 g Fe(NO3)3·9H2O (content 98.5%), 12.6 g Cu(NO3)2·6H2O (98.0%), and 123.5 g Co(NO3)2·6H2O (99.0%) were added to 250 g 75°C distilled water and stirred to obtain a mixed solution II. The mixed solution II was slowly added dropwise to a sodium hydroxide-sodium carbonate mixed solution (sodium hydroxide concentration was 0.2 mol / L, sodium carbonate concentration was 0.25 mol / L) for 1.0 h. The pH value of the solution was controlled at 8. After the addition was completed, stirring was continued for 18 h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 140°C, and calcined at 700°C for 7 h to obtain Fe 0.8 Cu 0.2 Co2O4;

[0071] (3) 10.0 g of the ground CeW prepared in step (1) was added 0.7 Mn 0.1 Ti 0.2 O3 and 15.0 g of the ground Fe prepared in step (2) 0.8 Cu 0.2 Co2O4 was added to 300g of distilled water and stirred at 70°C. Then, 75.0g of nano-TiO2 was added to a beaker in batches and vigorously stirred for 5h. Then, 5.0g of carboxymethyl cellulose was added and stirred at 75°C for 7h to obtain a viscous slurry. The product was dried at 130°C, calcined at 600°C for 12h, crushed, and passed through a 40-60 mesh sieve to obtain a bifunctional catalyst composition.

[0072] Example 5

[0073] A method for preparing a bifunctional catalyst composition for removing NOx and CVOCs from flue gas comprises the following steps:

[0074] (1) 72.2g Ce(NO3)3·6H2O (content 98.0%), 20.6g (NH4)6H2W 12 O 40 ·4H2O (99.9%), 16.8g Mn(NO3)2·4H2O (97.5%) and 3.1g TiCl4 (99.5%) were added to 200g 50℃ distilled water and stirred to obtain a mixed solution 1, which was slowly added dropwise to a 5vol% ammonia solution for 2.0h. The pH value of the solution was controlled at 10. After the addition was completed, stirring was continued for 12h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 120℃, and calcined at 580℃ for 8h to obtain CeW 0.5 Mn 0.4 Ti 0.1 O3;

[0075] (2) 16.8 g of Fe(NO3)3·9H2O (content 98.5%), 49.6 g of Cu(NO3)2·6H2O (98.0%), and 120.3 g of Co(NO3)2·6H2O (99.0%) were added to 250 g of 75°C distilled water and stirred to obtain a mixed solution II. The mixed solution II was slowly added dropwise to a sodium hydroxide-sodium carbonate mixed solution (sodium hydroxide concentration was 0.2 mol / L, sodium carbonate concentration was 0.25 mol / L) for 1.0 h. The pH value of the solution was controlled at 8. After the addition was completed, stirring was continued for 18 h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 140°C, and calcined at 700°C for 7 h to obtain Fe 0.2 Cu 0.8 Co2O4;

[0076] (3) 12.0 g of the ground CeW prepared in step (1) was added 0.5 Mn 0.4 Ti 0.1 O3 and 15.0 g of the ground Fe prepared in step (2) 0.2 Cu 0.8 Co2O4 was added to 300g of distilled water and stirred at 70°C. Then, 68.0g of nano-TiO2 was added to the beaker in batches and stirred vigorously for 5h. Then, 5.0g of carboxymethyl cellulose was added and stirred at 75°C for 7h to obtain a viscous slurry. The product was dried at 130°C, calcined at 580°C for 10h, crushed, and passed through a 40-60 mesh sieve to obtain a bifunctional catalyst composition.

[0077] Example 6

[0078] A method for preparing a bifunctional catalyst composition for removing NOx and CVOCs from flue gas comprises the following steps:

[0079] (1) 72.2g Ce(NO3)3·6H2O (content 98.0%), 20.6g (NH4)6H2W 12 O 40 ·4H2O (99.9%), 16.8g Mn(NO3)2·4H2O (97.5%) and 3.1g TiCl4 (99.5%) were added to 200g 50℃ distilled water and stirred to obtain a mixed solution 1, which was slowly added dropwise to a 5vol% ammonia solution for 2.0h. The pH value of the solution was controlled at 10. After the addition was completed, stirring was continued for 12h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 120℃, and calcined at 580℃ for 8h to obtain CeW 0.5 Mn 0.4 Ti 0.1 O3;

[0080] (2) 68.9 g Fe(NO3)3·9H2O (content 98.5%), 12.6 g Cu(NO3)2·6H2O (98.0%), and 123.5 g Co(NO3)2·6H2O (99.0%) were added to 250 g 75°C distilled water and stirred to obtain a mixed solution II. The mixed solution II was slowly added dropwise to a sodium hydroxide-sodium carbonate mixed solution (sodium hydroxide concentration was 0.2 mol / L, sodium carbonate concentration was 0.25 mol / L) for 1.0 h. The pH value of the solution was controlled at 8. After the addition was completed, stirring was continued for 18 h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 140°C, and calcined at 700°C for 7 h to obtain Fe 0.8 Cu 0.2 Co2O4;

[0081] (3) 10.0 g of the ground CeW prepared in step (1) was added 0.5 Mn 0.4 Ti 0.1 O3 and 18.0 g of the ground Fe prepared in step (2) 0.8 Cu 0.2 Co2O4 was added to 300g of distilled water and stirred at 70°C. Then, 69.0g of nano-TiO2 was added to the beaker in batches and stirred vigorously for 5h. Then, 3.0g of carboxymethyl cellulose was added and stirred at 75°C for 7h to obtain a viscous slurry. The product was dried at 140°C, calcined at 580°C for 10h, crushed, and passed through a 40-60 mesh sieve to obtain a bifunctional catalyst composition.

[0082] Example 7

[0083] A method for preparing a bifunctional catalyst composition for removing NOx and CVOCs from flue gas comprises the following steps:

[0084] (1) 75.7g Ce(NO3)3·6H2O (content 98.0%), 17.3g (NH4)6H2W 12 O 40 ·4H2O (99.9%), 13.2g Mn(NO3)2·4H2O (97.5%) and 9.8g TiCl4 (99.5%) were added to 200g 50℃ distilled water and stirred to obtain a mixed solution 1, which was slowly added dropwise to 5vol% ammonia solution for 1.5h. The pH value of the solution was controlled at 9. After the addition was completed, stirring was continued for 10h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 130℃, and calcined at 600℃ for 7h to obtain CeW 0.4 Mn 0.3 Ti 0.3 O3;

[0085] (2) 68.9 g Fe(NO3)3·9H2O (content 98.5%), 12.6 g Cu(NO3)2·6H2O (98.0%), and 123.5 g Co(NO3)2·6H2O (99.0%) were added to 250 g 75°C distilled water and stirred to obtain a mixed solution II. The mixed solution II was slowly added dropwise to a sodium hydroxide-sodium carbonate mixed solution (sodium hydroxide concentration was 0.2 mol / L, sodium carbonate concentration was 0.25 mol / L) for 1.0 h. The pH value of the solution was controlled at 8. After the addition was completed, stirring was continued for 18 h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 140°C, and calcined at 700°C for 7 h to obtain Fe 0.8 Cu 0.2 Co2O4;

[0086] (3) 10.0 g of the ground CeW prepared in step (1) was added 0.4 Mn 0.3 Ti 0.3 O3 and 15.0 g of the ground Fe prepared in step (2) 0.8 Cu 0.2 Co2O4 was added to 300g of distilled water and stirred at 70°C. Then, 72.0g of nano-TiO2 was added to a beaker in batches and vigorously stirred for 5h. Then, 3.0g of carboxymethyl cellulose was added and stirred at 75°C for 8h to obtain a viscous slurry. The product was dried at 130°C, calcined at 600°C for 12h, crushed, and passed through a 40-60 mesh sieve to obtain a bifunctional catalyst composition.

[0087] Example 8

[0088] A method for preparing a bifunctional catalyst composition for removing NOx and CVOCs from flue gas comprises the following steps:

[0089] (1) 75.7g Ce(NO3)3·6H2O (content 98.0%), 17.3g (NH4)6H2W 12 O 40 ·4H2O (99.9%), 13.2g Mn(NO3)2·4H2O (97.5%) and 9.8g TiCl4 (99.5%) were added to 200g 50℃ distilled water and stirred to obtain a mixed solution 1, which was slowly added dropwise to 5vol% ammonia solution for 1.5h. The pH value of the solution was controlled at 9. After the addition was completed, stirring was continued for 10h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 130℃, and calcined at 600℃ for 7h to obtain CeW 0.4 Mn 0.3 Ti 0.3 O3;

[0090] (2) 16.8 g of Fe(NO3)3·9H2O (content 98.5%), 49.6 g of Cu(NO3)2·6H2O (98.0%), and 120.3 g of Co(NO3)2·6H2O (99.0%) were added to 250 g of 75°C distilled water and stirred to obtain a mixed solution II. The mixed solution II was slowly added dropwise to a sodium hydroxide-sodium carbonate mixed solution (sodium hydroxide concentration was 0.2 mol / L, sodium carbonate concentration was 0.25 mol / L) for 1.0 h. The pH value of the solution was controlled at 8. After the addition was completed, stirring was continued for 18 h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 140°C, and calcined at 700°C for 7 h to obtain Fe 0.2 Cu 0.8 Co2O4;

[0091] (3) 8.0 g of the ground CeW prepared in step (1) was added 0.4 Mn 0.3 Ti 0.3 O3 and 18.0 g of the ground Fe prepared in step (2) 0.2 Cu 0.8 Co2O4 was added to 300g of distilled water and stirred at 70°C. Then, 69.0g of nano-TiO2 was added to a beaker in batches and stirred vigorously for 5h. Then, 5.0g of corn starch was added and stirred at 75°C for 8h to obtain a viscous slurry. The product was dried at 130°C, calcined at 600°C for 12h, crushed, and passed through a 40-60 mesh sieve to obtain a bifunctional catalyst composition.

[0092] Example 9

[0093] A method for preparing a bifunctional catalyst composition for removing NOx and CVOCs from flue gas comprises the following steps:

[0094] (1) 83.5g Ce(NO3)3·6H2O (content 98.0%), 9.5g (NH4)6H2W 12 O 40 ·4H2O (99.9%), 19.3g Mn(NO3)2·4H2O (97.5%) and 14.3g TiCl4 (99.5%) were added to 200g 50℃ distilled water and stirred to obtain a mixed solution 1, which was slowly added dropwise to a 5vol% ammonia solution for 2.0h. The pH value of the solution was controlled at 10. After the addition was completed, stirring was continued for 12h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 120℃, and calcined at 600℃ for 7h to obtain CeW 0.2 Mn 0.4 Ti 0.4 O3;

[0095] (2) 33.8 g of Fe(NO3)3·9H2O (content 98.5%), 37.4 g of Cu(NO3)2·6H2O (98.0%), and 121.0 g of Co(NO3)2·6H2O (99.0%) were added to 250 g of 75°C distilled water and stirred to obtain a mixed solution II. The mixed solution II was slowly added dropwise to a sodium hydroxide-sodium carbonate mixed solution (sodium hydroxide concentration was 0.2 mol / L, sodium carbonate concentration was 0.25 mol / L) for 1.0 h. The pH value of the solution was controlled at 10. After the addition was completed, stirring was continued for 14 h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 130°C, and calcined at 700°C for 8 h to obtain Fe 0.4 Cu 0.6 Co2O4;

[0096] (3) 12.0 g of the ground CeW prepared in step (1) was added 0.2 Mn 0.4 Ti 0.4 O3 and 14.0 g of the ground Fe prepared in step (2) 0.4 Cu 0.6 Co2O4 was added to 300g of distilled water and stirred at 70°C. Then, 69.0g of nano-TiO2 was added to the beaker in batches and stirred vigorously for 5h. Then, 5.0g of corn starch was added and stirred at 75°C for 8h to obtain a viscous slurry. The slurry was dried at 140°C, calcined at 600°C for 10h, crushed, and passed through a 40-60 mesh sieve to obtain a bifunctional catalyst composition.

[0097] Example 10

[0098] A method for preparing a bifunctional catalyst composition for removing NOx and CVOCs from flue gas comprises the following steps:

[0099] (1) 83.5g Ce(NO3)3·6H2O (content 98.0%), 9.5g (NH4)6H2W 12 O 40 ·4H2O (99.9%), 19.3g Mn(NO3)2·4H2O (97.5%) and 14.3g TiCl4 (99.5%) were added to 200g 50℃ distilled water and stirred to obtain a mixed solution 1, which was slowly added dropwise to a 5vol% ammonia solution for 2.0h. The pH value of the solution was controlled at 10. After the addition was completed, stirring was continued for 12h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 120℃, and calcined at 600℃ for 7h to obtain CeW 0.2 Mn 0.4 Ti 0.4 O3;

[0100] (2) 68.9 g Fe(NO3)3·9H2O (content 98.5%), 12.6 g Cu(NO3)2·6H2O (98.0%), and 123.5 g Co(NO3)2·6H2O (99.0%) were added to 250 g 75°C distilled water and stirred to obtain a mixed solution II. The mixed solution II was slowly added dropwise to a sodium hydroxide-sodium carbonate mixed solution (sodium hydroxide concentration was 0.2 mol / L, sodium carbonate concentration was 0.25 mol / L) for 1.0 h. The pH value of the solution was controlled at 8. After the addition was completed, stirring was continued for 18 h for nucleation and crystallization. The product was cooled, filtered, washed until neutral, dried at 140°C, and calcined at 700°C for 7 h to obtain Fe 0.8 Cu 0.2 Co2O4;

[0101] (3) 10.0 g of the ground CeW prepared in step (1) was added 0.2 Mn 0.4 Ti 0.4 O3 and 14.0 g of the ground Fe prepared in step (2) 0.8 Cu 0.2 Co2O4 was added to 300g of distilled water and stirred at 70°C. Then, 71.0g of nano-TiO2 was added to a beaker in batches and stirred vigorously for 5h. Then, 5.0g of corn starch was added and stirred at 75°C for 8h to obtain a viscous slurry. The product was dried at 130°C, calcined at 600°C for 12h, crushed, and passed through a 40-60 mesh sieve to obtain a bifunctional catalyst composition.

[0102] The performance of the dual-function catalysts for removing NOx and CVOCs from flue gas prepared in Examples 1 to 10 was evaluated. Specific data are shown in Table 1. The catalytic activity and stability tests were conducted in a continuous flow fixed-bed quartz tubular reactor. Before each test, 1 ml of catalyst (40-60 mesh) was loaded at a space velocity of 6000 h / min. -1 The reaction gas consists of 500×10 -6 NO, 500×10 -6 NH3, 100×10 -6 The reaction gas consists of CB (chlorobenzene), 5% O2, and residual N2, with a total flow rate of 100 L / min. The CB concentration in the reaction gas is controlled by adjusting the water bath temperature and the N2 stripping flow rate. The reaction exhaust gas contains NOx, CB, CO, CO2, O2, and residual N2. The concentrations of CB, CO, and CO2 in the exhaust gas are monitored online by gas chromatography, while the concentrations of NOx (NO, NO2, and N2O) and O2 are monitored by a flue gas analyzer.

[0103] The calculation formulas for CB conversion rate, CO and CO2 generation rate, NO removal rate, and N2 selectivity are as follows:

[0104]

[0105]

[0106]

[0107]

[0108]

[0109] Where: η CB is the CB conversion rate, η NO is the NO removal rate, Y CO and Y CO2 are the CO and CO2 production rates, S N2 It is N2 selective.

[0110] Table 1 Performance evaluation of bifunctional catalysts

[0111]

[0112] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A bifunctional catalyst composition for removing NOx and CVOCs from flue gas, characterized in that: Based on the weight of the composition, it is made of the following components: 5-15wt% CeW x Mn y Ti z O3, 10-20wt% Fe δ Cu 1-δ Co2O4, 60-80wt% nano-TiO2, 2-7wt% pore expanding agent.

2. The catalyst composition according to claim 1, characterized in that Based on the weight of the composition, it is made of the following components: 8-12wt% CeW x Mn y Ti z O3, 12-18 wt% Fe δ Cu 1-δ Co2O4, 65-75wt% nano-TiO2, 3-6wt% pore expanding agent.

3. The catalyst composition according to claim 1, characterized in that The CeW x Mn y Ti z In O3, x=0~0.9, z=0~0.6, y≤1-(x+z).

4. The catalyst composition according to claim 1, characterized in that The Fe δ Cu 1-δ In Co2O4, δ = 0.1 ~ 0.

9.

5. The catalyst composition according to claim 1, characterized in that The pore-enlarging agent is corn starch and / or carboxymethyl cellulose.

6. A method for preparing the catalyst composition according to any one of claims 1 to 5, characterized in that: The steps include: (1) Cerium salt, tungstate, manganese salt and titanium salt are dissolved to obtain a mixed solution 1, and the mixed solution 1 is added dropwise to an ammonia solution. After the addition is complete, stirring is continued. The product is cooled, filtered, washed until neutral, and then dried and calcined to obtain CeW x Mn y Ti z O3; (2) Dissolve the iron salt, copper salt and cobalt salt to obtain a mixed solution 2, add the mixed solution 2 dropwise to the sodium hydroxide-sodium carbonate mixed solution, continue stirring after the addition is complete, cool the product, filter it, wash it until it is neutral, then dry it and roast it to obtain Fe δ Cu 1-δ Co2O4; (3) CeW x Mn y Ti z O3 and Fe δ Cu 1-δ Co2O4 is added to distilled water and stirred once, then nano-TiO2 is added and stirred twice, and then a pore-enlarging agent is added and stirred three times to obtain a viscous slurry. The product is dried, roasted, crushed and sieved to obtain a catalyst composition.

7. The preparation method according to claim 6, characterized in that In step (1), the temperature of the mixed solution 1 is 40-55° C., the dropping time is 0.5-2.0 h, the solution pH is controlled at 8-10, and the stirring time is 10-18 h.

8. The preparation method according to claim 6, characterized in that In step (1), the drying temperature is 120-150° C., and the calcination condition is 550-650° C. for 4-10 hours.

9. The preparation method according to claim 6, characterized in that In step (2), the dropping time is 0.5 to 1 hour, the temperature during the dropping is 70 to 85° C., the pH value of the solution is controlled at 8 to 10, and the stirring time is 12 to 20 hours.

10. The preparation method according to claim 6, characterized in that In step (2), the drying temperature is 120-150° C., and the calcination condition is 650-750° C. for 6-12 hours.

11. The preparation method according to claim 6, characterized in that In step (2), the concentration of sodium hydroxide in the sodium hydroxide-sodium carbonate mixed solution is 0.1-0.3 mol / L, and the concentration of sodium carbonate is 0.15-0.35 mol / L.

12. The preparation method according to claim 6, characterized in that In step (3), the temperature during the first stirring is 50-70° C., the second stirring time is 3-5 h, and the third stirring condition is stirring at 65-85° C. for 4-8 h.

13. The preparation method according to claim 6, characterized in that In step (3), the drying temperature is 120-150° C., the roasting conditions are 500-600° C. for 6-12 hours, and the product is passed through a 40-60 mesh sieve.

14. Use of the catalyst composition according to any one of claims 1 to 5 in removing NOx and CVOCs from flue gas.

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