Denitration catalyst surface treatment method and application thereof

Abstract

The invention provides a denitration catalyst surface treatment method and application thereof, and the method comprises the following steps: 1) uniformly mixing cellulose, catalyst powder, an acrylic acid compound, a sulfonic acid compound and an amide compound to obtain a pretreatment mixed solution; (2) uniformly loading the pretreated mixed solution onto the surface of a denitration catalyst to be treated; and 3) drying the loaded denitration catalyst. When the denitration catalyst treated by the method is used, dust, metal ammonium sulfate and other dirt on the surface of the catalyst can be effectively prevented from being deposited on the catalyst under the condition that the catalyst is not taken out, the activity of the catalyst is recovered, the denitration efficiency is improved, and meanwhile, the production cost and the operation difficulty are reduced.

Description

Technical Field

[0001] This invention relates to the fields of environmental protection and industrial catalysis technology, and more specifically, to a surface treatment method for denitrification catalysts and its application. Background Technology

[0002] In denitrification processes, denitrification catalysts are exposed to complex flue gas environments for extended periods, making their surfaces prone to accumulating various contaminants such as dust and ammonium sulfate. The presence of these contaminants severely impacts the catalyst's active sites, reduces its denitrification efficiency, and increases system operating resistance and energy consumption. Most existing contaminant removal methods require removing the catalyst from the equipment for offline processing. For example, CN109126903A discloses a method of preparing a regeneration cleaning solution according to a formula and immersing the deactivated plate-type denitrification catalyst in the solution for cleaning. Current technologies typically involve removing the catalyst and placing it in the cleaning solution, which is not only cumbersome and resource-intensive but also leads to production interruptions, impacting the company's economic benefits. Therefore, developing an efficient and convenient in-situ method for removing contaminants from the surface of denitrification catalysts is of significant practical importance. Summary of the Invention

[0003] To address the aforementioned problems in the background art, the purpose of this invention is to provide a surface treatment method for denitrification catalysts and its application, which enables the effective removal of dust, ammonium sulfate, and other contaminants from the catalyst surface without removing the catalyst during use, thereby restoring the catalyst's activity, improving denitrification efficiency, and simultaneously reducing production costs and operational difficulty.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] In a first aspect, the present invention provides a method for surface treatment of a denitrification catalyst, comprising the following steps:

[0006] 1) Mix cellulose, catalyst powder, acrylic acid compound, sulfonic acid compound and amide compound evenly to obtain a pretreated mixture;

[0007] 2) The pretreated mixture is uniformly loaded onto the surface of the denitrification catalyst to be treated;

[0008] 3) Dry the loaded denitrification catalyst.

[0009] Further, in step 1), the catalyst powder is selected from one or more vanadium-titanium denitration catalysts.

[0010] Further, in step 1), the acrylic compound is selected from one or more of acrylic acid, methacrylic acid, etc.

[0011] Further, in step 1), the sulfonic acid compound is selected from one or more of p-toluenesulfonic acid, dodecylbenzenesulfonic acid, etc.

[0012] Furthermore, in step 1), the amide compound is selected from one or more of acetamide, acrylamide, etc.

[0013] Further, in step 1), cellulose and catalyst powder are soaked in a mixed solution containing acrylic acid compounds and sulfonic acid compounds, and amide compounds are added to the mixed solution and stirred thoroughly. Preferably, the stirring speed is 1000 r / min or higher, and the stirring time is 2-4 hours.

[0014] Further, in step 1), the mass ratio of cellulose to catalyst powder ranges from 1-20:1-5;

[0015] The ratio of the total mass of the cellulose and catalyst powder to the total mass of the acrylic acid compound, sulfonic acid compound, and amide compound is 1:5 to 1:50;

[0016] The mass ratio of the acrylic acid compound to the sulfonic acid compound in the pretreatment mixture is 0.5:1-2:1.

[0017] Further, in step 2), the loading method is selected from spraying or immersion; preferably, the immersion time is 2-24 hours.

[0018] Further, in step 3), the drying conditions include: the drying temperature is controlled at 30-80℃, the heating rate is 2-7℃ / minute, and the drying time is 2-24 hours.

[0019] Secondly, the present invention provides an application of the denitrification catalyst treated by the above method, which is placed in a flowing denitrification flue gas environment, with the gas flow rate controlled at 500 mL / min, and the direction of the gas flow being introduced at a horizontal angle to the catalyst surface.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] The pretreatment mixture of this invention uses cellulose as the base raw material, as cellulose has good adsorption and dispersion properties. A suitable amount of catalyst powder is also prepared, which has the same or similar composition as the denitrification catalyst to be treated. Its role is to assist in the removal of fouling in subsequent processes and to maintain the stability of the catalyst's active sites during treatment. The cellulose and catalyst powder are soaked in a mixed solution containing acrylic acid compounds and sulfonic acid compounds. Acrylic acid compounds have good polymerization properties and affinity for fouling; sulfonic acid compounds have strong acidity and surface activity, which helps in the decomposition and dissolution of fouling. Amide compounds are also added to the above mixed solution and stirred thoroughly. Amide compounds can enhance the interaction between the components in the mixture and also have a complexing effect on some metal ions, which is beneficial for the removal of fouling such as ammonium sulfate. All components are ensured to be thoroughly and uniformly mixed to form the pretreatment mixture.

[0022] The prepared pretreated mixture is uniformly loaded onto the surface of the denitrification catalyst to be treated. Ensure that the pretreated mixture fully covers the catalyst surface and fully penetrates the pore structure of the catalyst.

[0023] After loading is complete, the catalyst is dried. The drying process helps the components in the pretreated mixture to initially solidify and react on the catalyst surface, forming an active layer with descaling function.

[0024] After the denitrification catalyst treated by the method of this invention was subjected to simulated flue gas and airflow for a period of time, the removal efficiency of dust, ammonium sulfate and other contaminants on the catalyst surface was examined. It was found that through the synergistic effect of cellulose, acrylic compounds, sulfonic acid compounds and amide compounds, dust and ammonium sulfate and other contaminants on the catalyst surface can be effectively decomposed and removed, significantly improving the catalyst activity and denitrification efficiency.

[0025] Other features and advantages of the present invention will be described in detail through the following specific embodiments. Detailed Implementation

[0026] The specific embodiments of the present invention will be described in detail below. It should be understood that the following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Various changes, modifications, substitutions, and variations made by those skilled in the art to these embodiments without departing from the principles and spirit of the present invention should be included within the scope of protection of the present invention.

[0027] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and should be understood to include those approximate. For numerical ranges, the endpoint values ​​of the ranges, the endpoint values ​​of the ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0028] In a first aspect, the present invention provides a method for surface treatment of a denitrification catalyst, comprising the following steps:

[0029] 1) Mix cellulose, catalyst powder, acrylic acid compound, sulfonic acid compound and amide compound evenly to obtain a pretreated mixture;

[0030] 2) The pretreated mixture is uniformly loaded onto the surface of the denitrification catalyst to be treated;

[0031] 3) Dry the loaded denitrification catalyst.

[0032] In some specific embodiments, in step 1), the catalyst powder is selected from one or more vanadium-titanium denitration catalysts.

[0033] In some specific embodiments, in step 1), the acrylic compound is selected from one or more of acrylic acid, methacrylic acid, etc.

[0034] In some specific embodiments, in step 1), the sulfonic acid compound is selected from one or more of p-toluenesulfonic acid, dodecylbenzenesulfonic acid, etc.

[0035] In some specific embodiments, in step 1), the amide compound is selected from one or more of acetamide, acrylamide, etc.

[0036] In some specific embodiments, in step 1), cellulose and catalyst powder are soaked in a mixed solution containing acrylic acid compounds and sulfonic acid compounds, an amide compound is added to the mixed solution, and the mixture is stirred thoroughly.

[0037] Preferably, the stirring speed is controlled at 1000 r / min or higher, and the stirring time is 2-4 hours.

[0038] In some specific embodiments, in step 1), the mass ratio of cellulose to catalyst powder is in the range of 1-20:1-5; setting the mass ratio as described above can promote the full combination of catalyst powder and cellulose, so that the surface binder can better retain the original surface of the catalyst.

[0039] The ratio of the total mass of cellulose and catalyst powder to the total mass of acrylic acid compounds, sulfonic acid compounds and amide compounds is 1:5 to 1:50; setting the mass ratio as described above can improve the surface performance of the catalyst and effectively reduce the amount of dust deposition.

[0040] The mass ratio of acrylic acid compounds to sulfonic acid compounds in the pretreatment mixture is 0.5:1-2:1; setting the mass ratio as described above can bring about a better dust suppression effect.

[0041] In some specific embodiments, in step 2), the loading method is selected from one of spraying, impregnation, etc., to ensure that the pretreated mixture can fully cover the catalyst surface.

[0042] Preferably, the impregnation time is 2-24 hours, allowing the pretreated mixture to fully penetrate into the pore structure of the catalyst.

[0043] In some specific embodiments, in step 3), the drying conditions include: a drying temperature controlled at 30-80°C, a heating rate of 2-7°C / minute, and a drying time of 2-24 hours. Using these parameters for slow drying can prevent damage to the catalyst due to excessively rapid temperature changes, while ensuring that the mixture is fully solidified on the catalyst surface.

[0044] Secondly, this invention provides an application of the denitrification catalyst treated by the above method, which is placed in a flowing denitrification flue gas environment with the airflow velocity controlled at 500 mL / min and the airflow introduction direction at a horizontal angle to the catalyst surface. The introduction of the airflow allows the simulated flue gas to flow uniformly over the catalyst surface, promoting the reaction between the pretreated mixture and the fouling; it also promptly removes the reaction products, preventing secondary pollution. The airflow introduction direction at a certain angle to the catalyst surface enhances the scouring effect of the airflow on the catalyst surface.

[0045] In this invention, a real flue gas environment is simulated in an actual denitrification device. The denitrification catalyst, after surface treatment using the method of this invention, is subjected to simulated flue gas and airflow for a period of time. Specific detection methods are then used to examine the removal efficiency of dust, ammonium sulfate, and other contaminants on the catalyst surface. For example, for dust, a gravimetric method can be used, weighing the catalyst before and after treatment to calculate the amount of dust removed. For ammonium sulfate, chemical analysis methods can be used to detect the changes in the content of metal ions and sulfate ions on the catalyst surface before and after treatment, thereby calculating the removal efficiency of ammonium sulfate.

[0046] The technical solution of the present invention will be further described in detail below with reference to the embodiments.

[0047] The embodiments of the present invention use a honeycomb vanadium-titanium denitration catalyst, the main components of which are TiO2 and V2O5, and the shape is honeycomb with a cross section of 150*150mm.

[0048] Example 1

[0049] 1) Preparation of pretreatment mixture

[0050] Weigh out 10g of cellulose and 5g of vanadium-titanium denitration catalyst powder, and soak them in a mixed solution containing 50g of acrylic acid and 30g of p-toluenesulfonic acid.

[0051] Add 20g of acetamide to the mixed solution and stir at 150 rpm for 3 hours to prepare a pretreated mixture.

[0052] 2) Pretreatment mixture loading

[0053] A piece of denitrification catalyst with an area of ​​150 cm2 was impregnated in the pretreatment mixture for 2 hours.

[0054] 3) Drying treatment

[0055] After the impregnated denitrification catalyst is removed, it is placed in an oven and heated to 70°C at a rate of 4°C / min, and dried for 2.5 hours.

[0056] 4) Simulated flue gas and airflow introduction

[0057] In the simulated flue gas device, the simulated flue gas components include SO2: 0.04%, O2: 4%, [NO] = [NH3] = 1000ppm, dust content 20ppm, and N2: balance gas (its content is determined by 100% minus other gases).

[0058] The gas flow rate was 500 ml / min, the gas flow direction was at a 45° angle to the catalyst surface, and the reaction time was 24 hours.

[0059] Dirt removal efficiency evaluation

[0060] Tests showed that the dust removal efficiency reached 80%, and the ammonium sulfate metal removal efficiency reached 75%.

[0061] Example 2

[0062] 1) Preparation of pretreatment mixture

[0063] Weigh out 12g of cellulose and 6g of vanadium-titanium denitration catalyst powder, and soak them in a mixed solution containing 60g of methacrylic acid and 40g of dodecylbenzenesulfonic acid.

[0064] Add 25g of acrylamide to the mixed solution and stir at 200 rpm for 3.5 hours to prepare a pretreated mixture.

[0065] 2) Pretreatment mixture loading

[0066] A 180cm² denitrification catalyst was loaded onto the pretreated mixture using a spraying method.

[0067] 3) Drying treatment

[0068] The loaded denitrification catalyst was placed in an oven and heated to 80°C at a rate of 5°C / min, and dried for 3 hours.

[0069] 4) Simulated flue gas and airflow introduction

[0070] In the simulated flue gas device, the simulated flue gas components include SO2: 0.04%, O2: 4%, [NO] = [NH3] = 1000ppm, dust content 20ppm, and N2: balance gas (its content is determined by 100% minus other gases).

[0071] The gas flow rate was 500 ml / min, the gas flow direction was at a 45° angle to the catalyst surface, and the reaction time was 24 hours.

[0072] Dirt removal efficiency evaluation

[0073] Tests showed that the dust removal efficiency reached 85%, and the ammonium sulfate metal removal efficiency reached 80%.

[0074] Example 3

[0075] The difference from Example 1 is that it contains 15g of acrylic acid and 30g of p-toluenesulfonic acid.

[0076] Tests showed that the dust removal efficiency reached 82%, and the ammonium sulfate metal removal efficiency reached 84.33%.

[0077] Example 4

[0078] The difference from Example 1 is that it contains 60g of acrylic acid and 30g of p-toluenesulfonic acid.

[0079] The dust removal efficiency was tested to be 84.56%, and the ammonium sulfate metal removal efficiency was 87.22%.

[0080] Example 5

[0081] The difference from Example 1 is that: 20g of cellulose and 5g of vanadium-titanium denitration catalyst powder.

[0082] The dust removal efficiency was tested to be 87.22%, and the ammonium sulfate metal removal efficiency was 83.17%.

[0083] Example 6

[0084] The difference from Example 1 is that: 5g of cellulose and 5g of vanadium-titanium denitration catalyst powder are used.

[0085] The dust removal efficiency was 84.78%, and the ammonium sulfate metal removal efficiency was 86.66%.

[0086] Example 7

[0087] The difference from Example 2 is that the temperature was increased to 50°C at a rate of 7°C / minute, and then dried for 5 hours.

[0088] The dust removal efficiency was tested to be 86.56%, and the ammonium sulfate metal removal efficiency was 86.33%.

[0089] Comparative Example 1

[0090] The difference from Example 1 is that acetamide is not added.

[0091] Tests showed that the dust removal efficiency reached 20%, and the ammonium sulfate metal removal efficiency reached 40.68%.

[0092] Comparative Example 2

[0093] The difference from Example 1 is that acrylic acid is not added, but 80g of p-toluenesulfonic acid is added.

[0094] The dust removal efficiency was 45.22%, and the ammonium sulfate metal removal efficiency was 38.99%.

[0095] Comparative Example 3

[0096] The difference from Example 1 is that p-toluenesulfonic acid was not added, but 80g of acrylic acid was added.

[0097] The dust removal efficiency was 39.67%, and the ammonium sulfate metal removal efficiency was 56.78%.

[0098] Comparative Example 4

[0099] The difference from Example 1 is that the drying was too fast, the drying temperature was 80°C, and the heating rate was 10°C / minute.

[0100] The dust removal efficiency was 47.33%, and the ammonium sulfate removal efficiency was 54.67%.

[0101] Comparative Example 5

[0102] The difference from Example 1 is as follows: 10g of cellulose and 5g of vanadium-titanium denitration catalyst powder were weighed and soaked in an aqueous solution containing 100g of ethanol, and stirred at 150 rpm for 3 hours to prepare a pretreatment mixture. Everything else was the same as in Example 1.

[0103] The dust removal efficiency was 22.57%, and the ammonium sulfate metal removal efficiency was 47.98%.

[0104] As can be seen from the above embodiments, this invention, through the synergistic effect of cellulose, acrylic acid, sulfonic acid, and amide compounds, can effectively decompose and remove dust and metal ammonium sulfate and other contaminants from the catalyst surface, significantly improving catalyst activity and denitrification efficiency. This invention achieves in-situ removal of contaminants from the denitrification catalyst surface, eliminating the need to remove the catalyst from the equipment during use, avoiding production interruptions caused by offline processing, greatly improving production efficiency, and reducing production costs. The entire process is simple to operate, requires common equipment, and is easy to promote and apply in actual production.

[0105] Although the present invention has been described in detail through the preferred embodiments described above, it should be understood that the above description should not be considered as a limitation of the present invention. Those skilled in the art will understand that modifications or adjustments can be made to the present invention based on the teachings of this specification. These modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A method for surface treatment of a denitrification catalyst, characterized in that, Includes the following steps: 1) Mix cellulose, catalyst powder, acrylic acid compound, sulfonic acid compound and amide compound evenly to obtain a pretreated mixture; 2) The pretreated mixture is uniformly loaded onto the surface of the denitrification catalyst to be treated; 3) Dry the loaded denitrification catalyst.

2. The surface treatment method for the denitrification catalyst according to claim 1, characterized in that, In step 1), the catalyst powder is selected from one or more vanadium-titanium denitration catalysts.

3. The surface treatment method for the denitrification catalyst according to claim 1 or 2, characterized in that, In step 1), the acrylic compound is selected from one or more of acrylic acid and methacrylic acid.

4. The surface treatment method for the denitrification catalyst according to any one of claims 1-3, characterized in that, In step 1), the sulfonic acid compound is selected from one or more of p-toluenesulfonic acid and dodecylbenzenesulfonic acid.

5. The surface treatment method for the denitrification catalyst according to any one of claims 1-4, characterized in that, In step 1), the amide compound is selected from one or more of acetamide and acrylamide.

6. The surface treatment method for the denitrification catalyst according to any one of claims 1-5, characterized in that, In step 1), cellulose and catalyst powder are soaked in a mixed solution containing acrylic acid compounds and sulfonic acid compounds. An amide compound is added to the mixed solution and stirred thoroughly; preferably at a speed of 1000 r / min or higher, for a stirring time of 2-4 hours.

7. The surface treatment method for the denitrification catalyst according to claim 1, characterized in that, In step 1), the mass ratio of cellulose to catalyst powder ranges from 1-20:1-5; The ratio of the total mass of the cellulose and catalyst powder to the total mass of the acrylic acid compound, sulfonic acid compound, and amide compound is 1:5 to 1:50; In step 1), the mass ratio of the acrylic compound to the sulfonic acid compound in the pretreatment mixture is 0.5:1-2:

1.

8. The surface treatment method for the denitrification catalyst according to claim 1, characterized in that, In step 2), the loading method is selected from spraying or immersion; preferably, the immersion time is 2-24 hours.

9. The surface treatment method for the denitrification catalyst according to claim 1, characterized in that, In step 3), the drying conditions include: the drying temperature is controlled at 30-80℃, the heating rate is 2-7℃ / minute, and the drying time is 2-24 hours.

10. The application of the denitrification catalyst treated by the method of any one of claims 1-9, wherein the catalyst is placed in a flowing denitrification flue gas environment, the gas flow rate is controlled at a total gas flow rate of 500 mL / min, and the direction of the gas flow is at a horizontal angle to the catalyst surface.