Plate-type denitration catalyst with high water resistance and sulfur resistance and preparation method of plate-type denitration catalyst

Abstract

The invention relates to the technical field of denitration catalysts, and discloses a plate-type denitration catalyst with high water resistance and sulfur resistance and a preparation method thereof.The preparation method comprises the steps that activated carbon is pretreated through nitric acid, then Fe-Mn in different proportions is loaded on the activated carbon through an impregnation method, and a Fe-Mn / AC carbon-based catalyst is obtained; and finally, modifying the carbon-based catalyst through nitrogen doping to obtain Fe-Mn / ACN-X. The obtained denitration catalyst has high water resistance and sulfur resistance, improves active sites of a carbon-based catalyst carrier and provides more adsorption sites for adsorption of gaseous NOx, so that the reaction between NH3 and NOx in an adsorption state is promoted.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of denitration catalysts, in particular to a high water and sulfur resistant plate type denitration catalyst and a preparation method thereof. BACKGROUND

[0002] Nitrogen oxides (NO x ) emitted by thermal power plants and motor vehicles are one of the main atmospheric pollutants, and high concentration of NO x emission will cause a series of environmental problems such as acid rain, photochemical fog and ozone layer hole. Ammonia selective catalytic reduction (NH3-SCR) is a widely used flue gas denitration technology in industry, but under normal circumstances, commercial V2O5-WO3(MoO3) / TiO2 catalysts have problems such as high working temperature, narrow active temperature range and strong biological toxicity of V2O5. Therefore, developing a low-temperature SCR catalyst with high efficiency, stability and non-toxicity has become a research hotspot for scholars at home and abroad. Activated carbon is often used as a low-temperature SCR catalyst due to its large specific surface area and rich surface functional groups.

[0003] For example, the patent with publication number (CN112121831A) discloses a wide temperature resistant sulfur and water resistant vanadium titanium denitration catalyst and a preparation method thereof. The denitration catalyst uses TiO2 as the carrier, V2O5 as the active component, MoO3, P2O5 and Nb2O5 as the active additives, and is prepared by impregnation method. The present application can remove nitrogen oxides with an efficiency of more than 90% in the temperature range of 160-370℃ by loading trace amounts of noble metal elements, can slow down the reaction rate of SO x with other substances such as NH3 to generate sulfite, thereby reducing the impact on the activity of the denitration catalyst and effectively preventing the blockage of the denitration catalyst pores, prolonging the service life of the denitration catalyst, and reducing the impact of high water content flue gas on the catalyst. The preparation method of the denitration catalyst provided by the present application is simple and easy to operate, and has high production efficiency.

[0004] However, V2O5 as the active component has problems such as high working temperature, narrow active temperature range and strong biological toxicity of V2O5, and the specific surface area of TiO2 is usually low (<100 m 2 / g), which limits the dispersion and loading of the active component. SUMMARY

[0005] (I) Technical problems solved In view of the deficiencies of the prior art, the present application provides a high water and sulfur resistant plate type denitration catalyst and a preparation method thereof.

[0006] The specific technical solution of the present application is as follows: the steps are as follows: 1) Pretreatment of activated carbon; 2) Preparation of catalysts; 3) Preparation of nitrogen-doped modified catalysts.

[0007] As a further description of the above technical solution: the pretreatment step of activated carbon includes: S1: grinding and screening activated carbon particles, controlling the mesh number of particle size; S2: weigh 10g of activated carbon particles, immerse them in 30mL of 10% nitric acid aqueous solution, and stand at room temperature for 24h to achieve chemical modification of the surface of activated carbon; S3: After soaking, rinse the activated carbon with distilled water until it is neutral to ensure that the surface residual acidic substances are removed.

[0008] As a further description of the above technical solution: the mesh number of activated carbon particles in S1 is 10-20 mesh, 20-40 mesh, and 40-60 mesh, respectively, the particle size in the three intervals.

[0009] The preparation steps of the catalyst include: S1: metal precursor solution configuration, the molar ratio of Fe to Mn is usually 1:1 to 3:1, and the total metal loading is controlled at 5-20wt%; S2: immerse the pretreated activated carbon in the metal salt solution, ensure that the solution volume matches the pore volume of the activated carbon, and stir at room temperature for 2-24 hours to make the metal ions uniformly adsorbed; S3: dry the impregnated sample at 100-120℃ for 12-24 hours to remove water and solvent; S4: calcine at 300-500℃ for 2-4 hours in air or inert atmosphere to decompose the metal salt into oxide (such as FeO3, MnO) or metal particles, form a stable structure, and obtain Fe-Mn / AC catalyst.

[0010] As a further description of the above technical solution: the calcination temperature of the catalyst preparation is controlled below 1000℃ to avoid sintering of active components or collapse of activated carbon structure caused by excessive temperature.

[0011] As a further description of the above technical solution: when the activated carbon is immersed in the metal salt solution in step 2 S2, the sample is dried and repeated after each impregnation to avoid metal agglomeration caused by excessive solution.

[0012] As a further description of the above technical solution: preparation of nitrogen-doped modified catalysts: S1: measure 20mL of distilled water, add 0.15g of urea, and stir well to dissolve completely.

[0013] As a further description of the above technical solution: S2: weigh 7g of Fe-Mn / AC catalyst and add it to the above solution, stand for 2h, and then put the sample into a drying oven at 80℃ for 24h.

[0014] As a further description of the above technical solution: S3: After drying is completed, the sample is transferred to a tube furnace, calcined for 3h under a nitrogen atmosphere, and naturally cooled to room temperature to obtain a nitrogen-doped modified catalyst marked as Fe-Mn / ACN-X; X is the calcination temperature under a nitrogen atmosphere.

[0015] As a further description of the above technical solution: In the preparation of the nitrogen-doped modified catalyst, samples with calcination temperatures of 300℃, 600℃ and 800℃ are prepared by changing the calcination temperature under a nitrogen atmosphere, and are marked as Fe-Mn / ACN-300, Fe-Mn / ACN-600 and Fe-Mn / ACN-800, respectively.

[0016] Beneficial technical effects: The prepared high water and sulfur resistance plate type denitration catalyst mainly improves the sulfur and water resistance of the catalyst by loading metal Fe-Mn on active carbon, further modifies the active carbon carrier by nitrogen doping, so that the catalyst can provide more adsorption sites, and the adsorption capacity of the catalyst for acidic NO x is improved, which promotes the reaction between adsorbed NH3 and NOx. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 are three main reaction equations of SCR. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present application clearer, the following embodiments are used to further illustrate the present application. The specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0019] The specific implementation of the present application is described in detail in combination with specific embodiments.

[0020] Example 1 1) Pretreatment of activated carbon: S1: Grind and sieve the activated carbon particles to control the particle size to 10-20 mesh; S2: Weigh 10g of activated carbon particles and immerse them in 30mL of 10% nitric acid aqueous solution, and stand at room temperature for 24h to achieve chemical modification of the surface of the activated carbon; S3: After soaking, wash the activated carbon with distilled water repeatedly until it is neutral to ensure that the surface residual acidic substances are removed.

[0021] 2) Preparation of catalyst: S1: Preparation of metal precursor solution, the molar ratio of Fe to Mn is usually 1:1, and the total metal loading is controlled at 5wt%; S2: The pretreated activated carbon is immersed in the metal salt solution, ensuring that the solution volume matches the pore volume of the activated carbon, and stirring at room temperature for 12 hours to allow uniform adsorption of metal ions; S3: The immersed sample is dried at 120°C for 12 hours to remove water and solvent; S4: Calcination at 500°C for 2 hours in air or inert atmosphere to decompose the metal salt into oxide (such as FeO3, MnO) or metal particles, forming a stable structure to obtain Fe-Mn / AC catalyst 3) Preparation of nitrogen-doped modified catalyst: S1: Measure 20mL distilled water, add 0.15g urea, and stir well until completely dissolved.

[0022] S2: Weigh 7g Fe-Mn / AC catalyst and add it to the above solution. After standing for 2h, the sample is placed in a drying oven at 80°C for 24h.

[0023] S3: After drying, the sample is transferred to a tube furnace and calcined at 300°C for 3h under nitrogen atmosphere, and naturally cooled to room temperature to obtain the nitrogen-doped modified catalyst marked as Fe-Mn / ACN-300.

[0024] Example 2: 1) Pretreatment of activated carbon: S1: Grind and sieve the activated carbon particles to control the particle size to 10-20 mesh; S2: Weigh 10g of activated carbon particles and immerse them in 30mL of 10% nitric acid aqueous solution, and stand at room temperature for 24h to achieve chemical modification of the activated carbon surface; S3: After soaking, rinse the activated carbon with distilled water until it is neutral to ensure removal of surface residual acidic substances.

[0025] 2) Preparation of catalyst: S1: Preparation of metal precursor solution, the molar ratio of Fe to Mn is usually 1:1, and the total metal loading is controlled at 5wt%; S2: The pretreated activated carbon is immersed in the metal salt solution, ensuring that the solution volume matches the pore volume of the activated carbon, and stirring at room temperature for 12 hours to allow uniform adsorption of metal ions; S3: The immersed sample is dried at 120°C for 12 hours to remove water and solvent; S4: Calcine at 500°C for 2 hours in air or an inert atmosphere to decompose the metal salt into oxides (such as FeO3, MnO) or metal particles, forming a stable structure to obtain the Fe-Mn / AC catalyst.

[0026] 3) Preparation of nitrogen-doped modified catalysts: S1: Measure 20mL of distilled water, add 0.15g of urea, and stir thoroughly until completely dissolved.

[0027] S2: Weigh 7g of Fe-Mn / AC catalyst, add it to the above solution, let it stand for 2 hours, and then put the sample into a drying oven at 80℃ for 24 hours.

[0028] S3: After drying, the sample was transferred to a tube furnace and calcined at 600°C for 3 hours under a nitrogen atmosphere. After natural cooling to room temperature, the nitrogen-doped modified catalyst was obtained and labeled as Fe-Mn / ACN-600.

[0029] Example 3: 1) Pretreatment of activated carbon: S1: Grind and sieve the activated carbon particles to control the particle size to 10~20 mesh; S2: Weigh 10g of activated carbon particles and soak them in 30mL of 10% nitric acid aqueous solution. Let them stand at room temperature for 24h to achieve chemical modification of the activated carbon surface. S3: After soaking, rinse the activated carbon repeatedly with distilled water until it is neutral to ensure that any residual acidic substances on the surface are removed.

[0030] 2) Catalyst preparation: S1: Preparation of metal precursor solution, with a typical molar ratio of Fe to Mn of 1:1 and a total metal loading controlled at 5 wt%; S2: Immerse the pretreated activated carbon in a metal salt solution, ensuring that the solution volume matches the pore volume of the activated carbon, and stir at room temperature for 12 hours to allow the metal ions to be uniformly adsorbed. S3: The impregnated sample is dried at 120°C for 12 hours to remove moisture and solvent; S4: Calcine at 500°C for 2 hours in air or an inert atmosphere to decompose the metal salt into oxides (such as FeO3, MnO) or metal particles, forming a stable structure to obtain the Fe-Mn / AC catalyst.

[0031] 3) Preparation of nitrogen-doped modified catalysts: S1: Measure 20mL of distilled water, add 0.15g of urea, and stir thoroughly until completely dissolved.

[0032] S2: Weigh 7g of Fe-Mn / AC catalyst, add it to the above solution, let it stand for 2 hours, and then put the sample into a drying oven at 80℃ for 24 hours.

[0033] S3: After drying, the sample was transferred to a tube furnace and calcined at 800°C for 3 hours under a nitrogen atmosphere. After natural cooling to room temperature, the nitrogen-doped modified catalyst was obtained and labeled as Fe-Mn / ACN-800.

[0034] Example 4: 1) Pretreatment of activated carbon: S1: Grind and sieve the activated carbon particles to control the particle size to 20~40 mesh; S2: Weigh 10g of activated carbon particles and soak them in 30mL of 10% nitric acid aqueous solution. Let them stand at room temperature for 24h to achieve chemical modification of the activated carbon surface. S3: After soaking, rinse the activated carbon repeatedly with distilled water until it is neutral to ensure that any residual acidic substances on the surface are removed.

[0035] 2) Catalyst preparation: S1: Preparation of metal precursor solution, with a typical molar ratio of Fe to Mn of 3:1 and a total metal loading controlled at 8 wt%; S2: Immerse the pretreated activated carbon in a metal salt solution, ensuring that the solution volume matches the pore volume of the activated carbon, and stir at room temperature for 12 hours to allow the metal ions to be uniformly adsorbed. S3: The impregnated sample is dried at 120°C for 12 hours to remove moisture and solvent; S4: Calcine at 300°C for 2 hours in air or an inert atmosphere to decompose the metal salt into oxides (such as FeO3, MnO) or metal particles, forming a stable structure to obtain the 3Fe-Mn / AC catalyst.

[0036] 3) Preparation of nitrogen-doped modified catalysts: S1: Measure 20mL of distilled water, add 0.15g of urea, and stir thoroughly until completely dissolved.

[0037] S2: Weigh 7g of Fe-Mn / AC catalyst, add it to the above solution, let it stand for 2 hours, and then put the sample into a drying oven at 80℃ for 24 hours.

[0038] S3: After drying, the sample was transferred to a tube furnace and calcined at 300°C for 3 hours under a nitrogen atmosphere. After natural cooling to room temperature, the nitrogen-doped modified catalyst was obtained and labeled as 3Fe-Mn / ACN-300.

[0039] Example 5: 1) Pretreatment of activated carbon: S1: Grind and sieve the activated carbon particles to control the particle size to 20~40 mesh; S2: Weigh 10g of activated carbon particles and soak them in 30mL of 10% nitric acid aqueous solution. Let them stand at room temperature for 24h to achieve chemical modification of the activated carbon surface. S3: After soaking, rinse the activated carbon repeatedly with distilled water until it is neutral to ensure that any residual acidic substances on the surface are removed.

[0040] 2) Catalyst preparation: S1: Preparation of metal precursor solution, with a typical molar ratio of Fe to Mn of 3:1 and a total metal loading controlled at 8 wt%; S2: Immerse the pretreated activated carbon in a metal salt solution, ensuring that the solution volume matches the pore volume of the activated carbon, and stir at room temperature for 12 hours to allow the metal ions to be uniformly adsorbed. S3: The impregnated sample is dried at 120°C for 12 hours to remove moisture and solvent; S4: Calcine at 300°C for 2 hours in air or an inert atmosphere to decompose the metal salt into oxides (such as FeO3, MnO) or metal particles, forming a stable structure to obtain the 3Fe-Mn / AC catalyst.

[0041] 3) Preparation of nitrogen-doped modified catalysts: S1: Measure 20mL of distilled water, add 0.15g of urea, and stir thoroughly until completely dissolved.

[0042] S2: Weigh 7g of Fe-Mn / AC catalyst, add it to the above solution, let it stand for 2 hours, and then put the sample into a drying oven at 80℃ for 24 hours.

[0043] S3: After drying, the sample was transferred to a tube furnace and calcined at 600°C for 3 hours under a nitrogen atmosphere. After natural cooling to room temperature, the nitrogen-doped modified catalyst was obtained and labeled as 3Fe-Mn / ACN-600.

[0044] Example 6: 1) Pretreatment of activated carbon: S1: Grind and sieve the activated carbon particles to control the particle size to 20~40 mesh; S2: Weigh 10g of activated carbon particles and soak them in 30mL of 10% nitric acid aqueous solution. Let them stand at room temperature for 24h to achieve chemical modification of the activated carbon surface. S3: After soaking, rinse the activated carbon repeatedly with distilled water until it is neutral to ensure that any residual acidic substances on the surface are removed.

[0045] 2) Catalyst preparation: S1: Preparation of metal precursor solution, with a typical molar ratio of Fe to Mn of 3:1 and a total metal loading controlled at 8 wt%; S2: Immerse the pretreated activated carbon in a metal salt solution, ensuring that the solution volume matches the pore volume of the activated carbon, and stir at room temperature for 12 hours to allow the metal ions to be uniformly adsorbed. S3: The impregnated sample is dried at 120°C for 12 hours to remove moisture and solvent; S4: Calcine at 300°C for 2 hours in air or an inert atmosphere to decompose the metal salt into oxides (such as FeO3, MnO) or metal particles, forming a stable structure to obtain the 3Fe-Mn / AC catalyst.

[0046] 3) Preparation of nitrogen-doped modified catalysts: S1: Measure 20mL of distilled water, add 0.15g of urea, and stir thoroughly until completely dissolved.

[0047] S2: Weigh 7g of Fe-Mn / AC catalyst, add it to the above solution, let it stand for 2 hours, and then put the sample into a drying oven at 80℃ for 24 hours.

[0048] S3: After drying, the sample was transferred to a tube furnace and calcined at 800°C for 3 hours under a nitrogen atmosphere. After natural cooling to room temperature, the nitrogen-doped modified catalyst was obtained and labeled as 3Fe-Mn / ACN-800.

[0049] Example 7: 1) Pretreatment of activated carbon: S1: Grind and sieve the activated carbon particles to control the particle size to 40~60 mesh; S2: Weigh 10g of activated carbon particles and soak them in 30mL of 10% nitric acid aqueous solution. Let them stand at room temperature for 24h to achieve chemical modification of the activated carbon surface. S3: After soaking, rinse the activated carbon repeatedly with distilled water until it is neutral to ensure that any residual acidic substances on the surface are removed.

[0050] 2) Catalyst preparation: S1: Preparation of metal precursor solution, with a typical molar ratio of Fe to Mn of 1:1 and a total metal loading controlled at 8 wt%; S2: Immerse the pretreated activated carbon in a metal salt solution, ensuring that the solution volume matches the pore volume of the activated carbon, and stir at room temperature for 12 hours to allow the metal ions to be uniformly adsorbed. S3: The impregnated sample is dried at 120°C for 12 hours to remove moisture and solvent; S4: Calcine at 300°C for 2 hours in air or an inert atmosphere to decompose the metal salt into oxides (such as FeO3, MnO) or metal particles, forming a stable structure to obtain the Fe-Mn / AC catalyst.

[0051] 3) Preparation of nitrogen-doped modified catalysts: S1: Measure 20mL of distilled water, add 0.15g of urea, and stir thoroughly until completely dissolved.

[0052] S2: Weigh 7g of Fe-Mn / AC catalyst, add it to the above solution, let it stand for 2 hours, and then put the sample into a drying oven at 80℃ for 24 hours.

[0053] S3: After drying, the sample was transferred to a tube furnace and calcined at 800°C for 3 hours under a nitrogen atmosphere. After natural cooling to room temperature, the nitrogen-doped modified catalyst was obtained and labeled as Fe-Mn / ACN-800.

[0054] Example 8: 1) Pretreatment of activated carbon: S1: Grind and sieve the activated carbon particles to control the particle size to 40~60 mesh; S2: Weigh 10g of activated carbon particles and soak them in 30mL of 10% nitric acid aqueous solution. Let them stand at room temperature for 24h to achieve chemical modification of the activated carbon surface. S3: After soaking, rinse the activated carbon repeatedly with distilled water until it is neutral to ensure that any residual acidic substances on the surface are removed.

[0055] 2) Catalyst preparation: S1: Preparation of metal precursor solution, with a typical molar ratio of Fe to Mn of 3:1 and a total metal loading controlled at 8 wt%; S2: Immerse the pretreated activated carbon in a metal salt solution, ensuring that the solution volume matches the pore volume of the activated carbon, and stir at room temperature for 12 hours to allow the metal ions to be uniformly adsorbed. S3: The impregnated sample is dried at 120°C for 12 hours to remove moisture and solvent; S4: Calcine at 300°C for 2 hours in air or an inert atmosphere to decompose the metal salt into oxides (such as FeO3, MnO) or metal particles, forming a stable structure to obtain the 3Fe-Mn / AC catalyst.

[0056] 3) Preparation of nitrogen-doped modified catalysts: S1: Measure 20mL of distilled water, add 0.15g of urea, and stir thoroughly until completely dissolved.

[0057] S2: Weigh 7g of Fe-Mn / AC catalyst, add it to the above solution, let it stand for 2 hours, and then put the sample into a drying oven at 80℃ for 24 hours.

[0058] S3: After drying, the sample was transferred to a tube furnace and calcined at 800°C for 3 hours under a nitrogen atmosphere. After natural cooling to room temperature, the nitrogen-doped modified catalyst was obtained and labeled as 3Fe-Mn / ACN-800.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A plate-type denitrification catalyst with high water and sulfur resistance and its preparation method, characterized in that, The steps are as follows: 1) Pretreatment of activated carbon; 2) Catalyst preparation; 3) Preparation of nitrogen-doped modified catalysts.

2. The highly water- and sulfur-resistant plate-type denitrification catalyst and its preparation method according to claim 1, characterized in that, Step 1 includes: S1: Grind and sieve the activated carbon particles to control the particle size in mesh. S2: Weigh 10g of activated carbon particles and soak them in 30mL of 10% nitric acid aqueous solution. Let them stand at room temperature for 24h to achieve chemical modification of the activated carbon surface. S3: After soaking, rinse the activated carbon repeatedly with distilled water until it is neutral to ensure that any residual acidic substances on the surface are removed.

3. The highly water- and sulfur-resistant plate-type denitrification catalyst and its preparation method according to claim 2, characterized in that, The activated carbon particles in S1 are selected from three mesh ranges: 10-20 mesh, 20-40 mesh, and 40-60 mesh.

4. The highly water- and sulfur-resistant plate-type denitrification catalyst and its preparation method according to claim 1, characterized in that, Step 2 includes: S1: Preparation of metal precursor solution, the molar ratio of Fe to Mn is usually 1:1 to 3:1, and the total metal loading is controlled at 5-20 wt%; S2: Immerse the pretreated activated carbon in a metal salt solution, ensuring that the solution volume matches the pore volume of the activated carbon, and stir at room temperature for 2-24 hours to allow the metal ions to be uniformly adsorbed. S3: After impregnation, the sample is dried at 100-120℃ for 12-24 hours to remove moisture and solvent; S4: Calcine at 300-500℃ for 2-4 hours in air or an inert atmosphere to decompose the metal salt into oxides (such as FeO3, MnO) or metal particles, forming a stable structure to obtain the Fe-Mn / AC catalyst.

5. The highly water- and sulfur-resistant plate-type denitrification catalyst and its preparation method according to claim 4, characterized in that, In step 2, the calcination temperature is controlled below 1000℃ to avoid excessively high temperatures that could cause the active components to sinter or the activated carbon structure to collapse.

6. The highly water- and sulfur-resistant plate-type denitrification catalyst and its preparation method according to claim 4, characterized in that, In step 2, when S2 activated carbon is immersed in the metal salt solution, it needs to be dried after each immersion before repeating the process to avoid excessive solution causing metal agglomeration.

7. The highly water- and sulfur-resistant plate-type denitrification catalyst and its preparation method according to claim 1, characterized in that, Step 3 includes: S1: Measure 20mL of distilled water, add 0.15g of urea, and stir thoroughly until completely dissolved; S2: Weigh 7g of Fe-Mn / AC catalyst, add it to the above solution, let it stand for 2 hours, and then put the sample into a drying oven at 80℃ for 24 hours; S3: After drying, the sample was transferred to a tube furnace and calcined in a nitrogen atmosphere for 3 hours. After natural cooling to room temperature, the nitrogen-doped modified catalyst was obtained and labeled as Fe-Mn / ACN-X. X represents the roasting temperature under a nitrogen atmosphere.

8. The highly water- and sulfur-resistant plate-type denitrification catalyst and its preparation method according to claim 7, characterized in that, In step 3, the samples were calcined for 3 hours under a nitrogen atmosphere. By changing the calcination temperature, samples with calcination temperatures of 300℃, 600℃, and 800℃ were prepared using the same method and labeled as Fe-Mn / ACN-300, Fe-Mn / ACN-600, and Fe-Mn / ACN-800, respectively.

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