Denitration catalyst and preparation method thereof

Abstract

The invention relates to the field of catalyst preparation, and discloses a denitration catalyst and a preparation method thereof. The preparation method of the denitration catalyst comprises the following steps: 1) in the presence of water, carrying out first contact on hydrogen peroxide, water and ammonium metavanadate to obtain a first contact product; 2) kneading, drying and roasting a catalyst raw material and the first contact product; wherein the dosage of hydrogen peroxide enables the ammonium metavanadate to be dissolved in the first contact product. According to the present invention, the denitration catalyst and the preparation method thereof can be provided, the hydrogen peroxide is adopted to replace ammonia water, monoethanolamine and other components capable of polluting the environment, no nitrogen oxide, inorganic ammonia or organic amine is discharged, the toxicity and the irritation to the human body are reduced, and the obtained catalyst has good catalytic performance.

Description

Technical Field

[0001] The present invention relates to the field of catalyst preparation, and in particular to a denitration catalyst and a preparation method thereof. Background Art

[0002] Ammonium metavanadate is an inorganic compound, mainly used as a chemical reagent, catalyst, drying agent, mordant, etc. Nitrogen oxides are one of the main air pollutants. At present, the country has strict requirements for the emission of nitrogen oxides. In the production process of denitrification catalysts, ammonium metavanadate is generally added as an active component precursor to make the catalyst have denitrification activity. Under normal temperature conditions, the solubility of ammonium metavanadate in water is very low. The solubility of ammonium metavanadate increases slightly with increasing temperature, but it is still low. Especially in the process of liquid transportation involved in production, it is easy to form condensation on the pipe wall. At present, ammonia water or monoethanolamine is added to dissolve ammonium metavanadate in production, but these two substances are very harmful to the human body. Ammonia water is very volatile and has great damage to the respiratory system and skin. Ethanolamine is also very toxic, which is not conducive to long-term contact. Summary of the invention

[0003] The purpose of the present invention is to overcome the problem of environmental pollution caused by ammonia water or monoethanolamine in the denitration catalyst in the prior art, and to provide a denitration catalyst and a preparation method thereof. The method uses hydrogen peroxide to replace components such as ammonia water and monoethanolamine that pollute the environment, and no nitrogen oxides, inorganic ammonia or organic amines are discharged, thereby reducing toxicity and irritation to the human body, and the obtained catalyst has good catalytic performance.

[0004] In order to achieve the above object, the first aspect of the present invention provides a method for preparing a denitration catalyst, characterized in that the method comprises the following steps:

[0005] 1) in the presence of water, bringing hydrogen peroxide into first contact with water and ammonium metavanadate to obtain a first contact product;

[0006] 2) kneading, drying and calcining the catalyst raw material and the first contact product;

[0007] The amount of hydrogen peroxide used is such that the ammonium metavanadate is dissolved in the first contact product.

[0008] Preferably, the weight ratio of the ammonium metavanadate, the hydrogen peroxide and the water is 1:1-20:0.6-10.

[0009] Preferably, the weight ratio of the ammonium metavanadate, the catalyst raw material and the carrier is 0.05-12:0.05-10:1.

[0010] Preferably, the catalyst raw material may include one or more of glass fiber, polyethylene oxide, carboxymethyl cellulose, stearic acid, hydroxypropyl methyl cellulose, starch and modified starch.

[0011] Preferably, the catalyst raw material includes one or more of glass fiber, polyethylene oxide, carboxymethyl cellulose and stearic acid.

[0012] Preferably, the carrier is one of titanium dioxide, zirconium dioxide, cerium dioxide, silicon dioxide, aluminum oxide, manganese oxide and activated carbon.

[0013] Preferably, the carrier is titanium dioxide.

[0014] Preferably, the drying conditions include: a temperature of 50-150° C. and a time of 6-240 h.

[0015] Preferably, the calcination conditions include: a temperature of 450-700° C. and a time of 3-48 hours.

[0016] A second aspect of the present invention provides a denitration catalyst, which is prepared by the preparation method of the denitration catalyst described in the first aspect of the present invention.

[0017] According to the present invention, a denitration catalyst and a preparation method thereof can be provided. In the method, hydrogen peroxide is used to replace components that pollute the environment, such as ammonia water and monoethanolamine, and no nitrogen oxides, inorganic ammonia or organic amines are discharged, thereby reducing toxicity and irritation to the human body, and the obtained catalyst has good catalytic performance. DETAILED DESCRIPTION

[0018] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0019] According to a first aspect of the present invention, a method for preparing a denitration catalyst is provided, the method comprising the following steps:

[0020] 1) in the presence of water, bringing hydrogen peroxide into first contact with water and ammonium metavanadate to obtain a first contact product;

[0021] 2) kneading, drying and calcining the catalyst raw material and the first contact product;

[0022] The amount of hydrogen peroxide used is such that the ammonium metavanadate is dissolved in the first contact product.

[0023] In the present invention, when hydrogen peroxide is used and the amount of hydrogen peroxide used is within the scope of the invention, ammonium metavanadate can be better dissolved, and the ammonium metavanadate can be ensured to be uniformly dispersed in the solution. During the preparation process, it is not affected by other factors, and there will be no heat or splashing. It has stability and good catalytic performance.

[0024] In the present invention, preferably, ammonium metavanadate is first mixed with water, and then hydrogen peroxide is slowly added to obtain a first contact product, wherein the concentration of hydrogen peroxide may be 10-99% by weight, preferably, the concentration of hydrogen peroxide is 10-35% by weight.

[0025] According to the present invention, preferably, in step 1), the weight ratio of the ammonium metavanadate, the hydrogen peroxide and the water is 1:1-20:0.6-10; more preferably, the weight ratio of the ammonium metavanadate, the hydrogen peroxide and the water is 1:1.5-18:0.7-6.

[0026] According to the present invention, the amount of the catalyst raw material can be determined according to the amount of the first contact product obtained in step 1). Preferably, in step 2), the weight ratio of the ammonium metavanadate, the catalyst raw material and the carrier is 0.05-12:0.05-10:1; more preferably, the weight ratio of the ammonium metavanadate, the catalyst raw material and the carrier is 0.1-11:0.1-5:1.

[0027] According to the present invention, in order to improve the performance of the denitration catalyst, raw materials used in the art to improve the performance of the catalyst can be added, and the catalyst raw materials may include one or more of glass fiber, polyethylene oxide, carboxymethyl cellulose, stearic acid, hydroxypropyl methyl cellulose, starch and modified starch; preferably, the catalyst raw materials include one or more of glass fiber, polyethylene oxide, carboxymethyl cellulose and stearic acid.

[0028] In a specific embodiment of the present invention, the catalyst raw materials are glass fiber, polyethylene oxide, carboxymethyl cellulose and stearic acid, and the weight ratio of glass fiber to catalyst carrier in the first contact product is 0.5-10:1, the weight ratio of polyethylene oxide to catalyst carrier in the first contact product is 0.001-0.1:1, the weight ratio of carboxymethyl cellulose to catalyst carrier in the first contact product is 0.0005-0.05:1, and the weight ratio of stearic acid to catalyst carrier in the first contact product is 0.0005-0.05:1.

[0029] According to the present invention, in order to improve the performance of the denitration catalyst, the carrier can be selected from one or more of titanium dioxide, zirconium dioxide, cerium dioxide, silicon dioxide, aluminum oxide, manganese oxide and activated carbon; preferably, the carrier is titanium dioxide.

[0030] According to the present invention, after the first contact product is obtained in step 1), the catalyst raw material and the first contact product are added to a kneading device for kneading. The kneading temperature may be 10-70° C. and the kneading time may be 0.4-2 h.

[0031] Preferably, water is added during the kneading process to soften and homogenize the material. The amount of water added here can be selected according to the amount of the carrier. Preferably, the weight ratio of the carrier to the water added in step 2) is 1:0.1-10; more preferably, the weight ratio of the carrier to the water added in step 2) is 1:1-5.

[0032] In the present invention, the kneading step in step 2) can be carried out in a kneading device commonly used in the art. Preferably, the kneading step is carried out using a kneader.

[0033] According to the present invention, after the kneading step, the kneaded material can be extruded and molded. The extrusion molding step can use an extruder commonly used in the art. Preferably, the extrusion molding uses an extruder.

[0034] In the present invention, the extrusion molding further includes the steps of drying and calcining.

[0035] According to the present invention, preferably, the drying conditions include: temperature of 50-150°C, time of 6-240h; more preferably, the drying conditions include: temperature of 55-90°C, time of 8-168h.

[0036] According to the present invention, preferably, the calcination conditions include: temperature of 450-700°C, time of 3-48h; more preferably, the calcination conditions include: temperature of 450-650°C, time of 3-24h.

[0037] According to a second aspect of the present invention, a denitration catalyst is provided, which is prepared by the preparation method of the denitration catalyst according to the first aspect of the present invention.

[0038] The present invention will be described in detail below by way of examples, but the present invention is not limited to the following examples.

[0039] Glass fiber: purchased from Lingshou Huashuo, specification is 9-20mm

[0040] Polyethylene oxide: purchased from Merck, molecular weight about 1,000,000

[0041] Carboxymethyl cellulose: purchased from Merck, sodium type, molecular weight about 700,000

[0042] Stearic acid: purchased from Merck, analytical grade

[0043] Ammonium metavanadate: purchased from Merck, analytical grade

[0044] Example 1

[0045] 1) Mix 3 g of ammonium metavanadate with 20 mL of water, and slowly add 20 mL of 30 wt % hydrogen peroxide to obtain a completely dissolved orange-red clear solution A;

[0046] 2) Add 200 g titanium dioxide, 3.1 g glass fiber, 0.86 g polyethylene oxide, 0.34 g carboxymethyl cellulose, 0.25 g stearic acid and all the orange-red clear solution A into a kneader; knead for 1 hour, and slowly add 70 mL water during the kneading process until the material becomes soft and uniform; extrude the material into strip catalysts, dry at 60° C. for one hour and at 80° C. overnight; and calcine at 550° C. for 4 hours to obtain a denitration catalyst A1.

[0047] Example 2

[0048] 1) Mix 3 g of ammonium metavanadate with 20 ml of water, and slowly add 60 ml of 30 wt % hydrogen peroxide to obtain a completely dissolved orange-red clear solution B;

[0049] 2) Add 200 g titanium dioxide, 3.1 g glass fiber, 0.86 g polyethylene oxide, 0.34 g carboxymethyl cellulose, 0.25 g stearic acid and all the orange-red clear solution B into a kneader; knead for 1 hour, and slowly add 60 mL water during the kneading process until the material becomes soft and uniform; extrude the material into strip catalysts, dry at 60° C. for one hour and at 80° C. overnight; and calcine at 550° C. for 4 hours to obtain a denitration catalyst A2.

[0050] Example 3

[0051] 1) Mix 6 g of ammonium metavanadate with 40 ml of water, and slowly add 40 ml of 30 wt % hydrogen peroxide to obtain a completely dissolved orange-red clear solution C;

[0052] 2) Add 400 g of titanium dioxide, 6.2 g of glass fiber, 1.72 g of polyethylene oxide, 0.68 g of carboxymethyl cellulose, 0.5 g of stearic acid and all of the orange-red clear solution C into a kneader; knead for 1 hour, and slowly add 130 mL of water during the kneading process until the material becomes soft and uniform; extrude the material into strip catalysts, dry at 60° C. for one hour and at 80° C. overnight; and calcine at 550° C. for 4 hours to obtain a denitration catalyst A3.

[0053] Example 4

[0054] 1) 3.5 g of ammonium metavanadate was stirred and mixed with 50 mL of water, and 9 mL of 30 wt % hydrogen peroxide was added to obtain a completely dissolved orange-red clear solution D;

[0055] 2) A denitration catalyst A4 was obtained in the same manner as step 2) of Example 1.

[0056] Example 5

[0057] 1) 3.5 g of ammonium metavanadate was stirred and mixed with 50 mL of water, and 12 mL of 30 wt % hydrogen peroxide was added to obtain a completely dissolved orange-red clear solution E;

[0058] 2) A denitration catalyst A5 was obtained in the same manner as step 2) of Example 1.

[0059] Example 6

[0060] 1) 7 g of ammonium metavanadate and 50 mL of water were stirred and mixed, and 15 mL of 30 wt % hydrogen peroxide was added to obtain a completely dissolved orange-red clear solution F;

[0061] 2) A denitration catalyst A6 was obtained in the same manner as step 2) of Example 1.

[0062] Example 7

[0063] 1) 10 g of ammonium metavanadate and 50 mL of water were stirred and mixed, and 24 mL of 30 wt % hydrogen peroxide was added to obtain a completely dissolved orange-red clear solution G;

[0064] 2) A denitration catalyst A7 was obtained in the same manner as step 2) of Example 1.

[0065] Comparative Example 1

[0066] 1) 3.5 g of ammonium metavanadate was stirred and mixed with 50 mL of water to obtain an incompletely dissolved solution;

[0067] 2) A denitration catalyst D1 was obtained in the same manner as step 2) of Example 1.

[0068] Comparative Example 2

[0069] 1) 3.5 g of ammonium metavanadate and 50 mL of water were stirred and mixed, and 6 mL of 30 wt % hydrogen peroxide was added to obtain an incompletely dissolved solution.

[0070] 2) A denitration catalyst D2 was obtained in the same manner as step 2) of Example 1.

[0071] Comparative Example 3

[0072] 1) 7 g of ammonium metavanadate was stirred and mixed with 50 mL of water, and 12 mL of 30 wt % hydrogen peroxide was added to obtain an incompletely dissolved solution;

[0073] 2) A denitration catalyst D3 was obtained in the same manner as step 2) of Example 1.

[0074] Comparative Example 4

[0075] 1) 10 g of ammonium metavanadate was stirred and mixed with 50 mL of water, and 15 mL of 30 wt % hydrogen peroxide was added to obtain an incompletely dissolved solution;

[0076] 2) A denitration catalyst D4 was obtained in the same manner as step 2) of Example 1.

[0077] Comparative Example 5

[0078] 1) 7 g of ammonium metavanadate was added to 50 mL of water and stirred at room temperature. No dissolution was observed.

[0079] 2) A denitration catalyst D5 was obtained in the same manner as step 2) of Example 1.

[0080] Comparative Example 6

[0081] 1) Add 7 g of ammonium metavanadate to 50 mL of water, add 7 g of ethanolamine, heat to 70 ° C, continue stirring, and observe the dissolution of ammonium metavanadate;

[0082] 2) A denitration catalyst D6 was obtained in the same manner as step 2) of Example 1.

[0083] Comparative Example 7

[0084] 1) 7 g of ammonium metavanadate was added to 50 mL of water, and 7 g of ethanolamine was added, and heated to 70° C. without stirring. Unsatisfactory dissolution was observed.

[0085] 2) A denitration catalyst D7 was obtained in the same manner as step 2) of Example 1.

[0086] Comparative Example 8

[0087] 1) Add 7 g of ammonium metavanadate to 50 mL of water, heat to 70 ° C, and continue stirring. No dissolution of ammonium metavanadate is observed;

[0088] 2) A denitration catalyst D8 was obtained in the same manner as step 2) of Example 1.

[0089] Test Example 1

[0090] The denitration catalysts obtained in Examples 1-7 and Comparative Examples 1-8 were used to perform denitration tests according to the following method. The results are shown in Table 1.

[0091] Denitrification test method: The catalyst was loaded into a size of 3.5cm*3.5cm*5.0cm, and the catalyst activity was evaluated under 1000ppmNO+1000ppmNH3+2%O2+N2. The test temperature was 300℃. The nitrogen oxide concentration was tested to determine the nitrogen oxide removal rate to evaluate the denitrification effect. The nitrogen oxide analysis was performed using an electrochemical sensor (purchased from CityTechnology, model 3NT CiTiceL electrochemical sensor). The denitrification efficiency was calculated according to (C NOx,入 -C NOx,出 ) / C NO,入 Perform calculations.

[0092] Table 1

[0093]

[0094] It can be seen from Examples 1-7 and Comparative Examples 1-8 that when ammonium metavanadate, water and hydrogen peroxide are used in amounts within the scope of the present invention, without using ammonia water and monoethanolamine, the ammonium metavanadate can be completely dissolved without producing components that pollute the environment or are toxic to the human body, and the denitrification activity is high.

[0095] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a denitration catalyst, characterized in that: The method comprises the following steps: 1) in the presence of water, bringing hydrogen peroxide into first contact with ammonium metavanadate to obtain a first contact product; 2) kneading, drying and calcining the catalyst raw material, the carrier and the first contact product; The amount of hydrogen peroxide used is such that the ammonium metavanadate is dissolved in the first contact product.

2. The preparation method according to claim 1, wherein In step 1), the weight ratio of the ammonium metavanadate, the hydrogen peroxide and the water is 1:1-20:0.6-10.

3. The preparation method according to claim 1, wherein In step 2), the weight ratio of the ammonium metavanadate, the catalyst raw material and the carrier is 0.05-12: 0.05-10：1。 4. The preparation method according to claim 3, wherein In step 2), the catalyst raw material may include one or more of glass fiber, polyethylene oxide, carboxymethyl cellulose, stearic acid, hydroxypropyl methyl cellulose, starch and modified starch.

5. The preparation method according to claim 4, wherein The catalyst raw materials include one or more of glass fiber, polyethylene oxide, carboxymethyl cellulose and stearic acid.

6. The preparation method according to claim 3, wherein: The carrier is one of titanium dioxide, zirconium dioxide, cerium dioxide, silicon dioxide, aluminum oxide, manganese oxide and activated carbon.

7. The preparation method according to claim 6, wherein: The carrier is titanium dioxide.

8. The method according to claim 1, wherein: The drying conditions include: temperature of 50-150° C. and time of 6-240 hours.

9. The method according to claim 1, wherein: The calcination conditions include: temperature of 450-700° C. and time of 3-48 hours.

10. A denitration catalyst, prepared by the method for preparing the denitration catalyst according to any one of claims 1 to 9.

Images