Flat plate denitration catalyst and preparation method thereof

Abstract

The application discloses a flat plate type denitration catalyst and a preparation method thereof, and belongs to the technical field of flue gas denitration. The catalyst paste comprises, in terms of weight parts, titanium white 70-80 parts, titanium-molybdenum composite powder 20-30 parts, stearic acid 1.5-2.5 parts, ammonium metavanadate 0.587-0.625 parts, ammonium molybdate 1.07-1.15 parts, glass fiber 3.1 parts, kaolin 5.4 parts, hydroxyethyl cellulose 0.3-1.1 parts, polyethylene oxide 0.4-0.8 parts, dispersant 0.3-0.6 parts and water 60 parts. In the preparation, the powder and the stearic acid are dry-mixed first, then the active liquid, the filler and the additive are sequentially added, the water content of the discharged material is controlled to be 27.0%-29.0%, and the pH is controlled to be 8.0-8.6, after aging and granulation, the polytetrafluoroethylene coating roller is used for rolling and molding, and then drying and calcination are carried out, and the flat plate type denitration catalyst is obtained. Through the synergistic compounding of the stearic acid, the hydroxyethyl cellulose, the polyethylene oxide and the dispersant, and the accurate control of the water content, the rolling and meshing rate is greater than 99.9%, the roller sticking rate is less than 0.1%, the plate thickness is uniform and controllable, the wear resistance is stable at 120-150 mg / 100r, the molding performance and the product consistency are significantly improved, and the flat plate type denitration catalyst is suitable for large-scale production.

Description

Technical Field

[0001] This invention relates to the field of flue gas denitrification technology, specifically to a flat-plate denitrification catalyst and its preparation method. Background Technology

[0002] With increasingly stringent industrial emission control requirements, SCR (Selective Catalysis) denitrification has become the mainstream flue gas treatment technology, and the catalyst is the core of the SCR system. Flat-plate denitrification catalysts are widely used in coal-fired power plants, industrial boilers, glass kilns, and other fields due to their advantages such as high activity, resistance to ash buildup, wear resistance, and ease of cleaning.

[0003] Flat-plate catalyst production uses a steel mesh framework, where catalyst paste is mixed, aged, granulated, rolled, coated, dried, and calcined. However, in actual production, the following prominent problems still exist:

[0004] (1) The paste adheres severely to the PTFE coating roller, resulting in a low on-line rate and difficulty in forming;

[0005] (2) The paste has poor rheological properties, is hard and brittle, and has poor uniformity of thickness after rolling.

[0006] (3) The ratio of additives is unreasonable, resulting in large fluctuations in the wear resistance of the product;

[0007] (4) Laboratory formulations are difficult to scale up stably to industrial production.

[0008] Currently, existing technologies are mostly limited to making single adjustments to cellulose or lubricants, making it difficult to simultaneously meet multiple requirements such as anti-sticking rollers, high on-line rate, high wear resistance, and scalability for production. Summary of the Invention

[0009] To address the problems of roller adhesion, low online production rate, uneven molding, large fluctuations in wear resistance, and difficulty in scaling up production in existing technologies, this invention provides a flat-plate denitrification catalyst paste, its preparation method, and the catalyst itself. This invention achieves a roller-pressed online production rate >99.9% and a roller adhesion rate <0.1% through the synergistic compounding of stearic acid, hydroxyethyl cellulose, polyethylene oxide, and a dispersant, combined with precise control of moisture content. Simultaneously, it ensures uniform plate thickness and stable wear resistance, meeting the requirements for large-scale production.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] A plate-type denitrification catalyst, the catalyst comprising a plate-shaped catalyst unit made of paste;

[0012] The ointment, by weight, consists of the following components:

[0013] The composition includes: 70-80 parts titanium dioxide, 20-30 parts titanium-molybdenum composite powder, 1.5-2.5 parts stearic acid, 0.587-0.625 parts ammonium metavanadate, 1.07-1.15 parts ammonium molybdate, 3.1 parts glass fiber, 5.4 parts kaolin, 0.3-1.1 parts hydroxyethyl cellulose, 0.4-0.8 parts polyethylene oxide, 0.3-0.6 parts dispersant, and 60 parts water.

[0014] The ointment is prepared by a method comprising the following steps:

[0015] Step S1: Take titanium dioxide, titanium molybdenum composite powder and stearic acid according to the ratio, put them into a mixer and dry mix for 5 to 15 minutes.

[0016] Step S2: Dissolve ammonium metavanadate in deionized water containing monoethanolamine at a temperature of 85℃~100℃, and dissolve ammonium molybdate in deionized water at room temperature. Mix the two solutions to obtain the active solution.

[0017] The amount of monoethanolamine used is sufficient to completely dissolve ammonium metavanadate.

[0018] Step S3: Add the active liquid obtained in step S2 into a mixer and mix for 20-40 minutes. Add ammonia water to adjust the pH of the system to 8.0-8.6.

[0019] Step S4: Add glass fiber and kaolin, and continue mixing for 20-40 minutes;

[0020] Step S5: Add hydroxyethyl cellulose, polyethylene oxide and dispersant while stirring. The addition method is to add them in two equal parts. Add half of the total amount in the first part, and add the remaining half after an interval of 5 to 10 minutes. Continue stirring until uniform. Control the moisture content of the discharged paste to be 27.0% to 29.0% and the pH to be 8.0 to 8.6.

[0021] Step S6: Seal and age to obtain the ointment.

[0022] The preparation method of the plate-type denitrification catalyst includes the following steps:

[0023] Step A: The paste described in claim 1 or 2 is aged for 20 to 28 hours and then rotary granulated to obtain granulated material, which is then placed at the inlet of the coating roller.

[0024] Step B: The coating roller rolls the granulated material to form a flat wet blank.

[0025] Step C: The flat wet blank is dried at 60℃~110℃ for 2~3 hours, and then calcined at 500℃~5500℃ for 2~3 hours to obtain a flat denitrification catalyst.

[0026] The coating roller is a polytetrafluoroethylene coating roller.

[0027] According to the above technical solution, the catalyst paste provided by the present invention achieves a roll forming rate of >99%, a roller sticking area of ​​<1%, an abrasion resistance of 120-150 mg / 100r, and a plate thickness of 0.65 mm-0.75 mm by compounding stearic acid, HEC, PEO, dispersant and precise control of moisture content.

[0028] The present invention has the following beneficial effects:

[0029] This invention addresses the shortcomings of traditional flat-plate denitrification catalyst pastes, such as severe roller sticking, low on-line yield, uneven forming, and large fluctuations in wear resistance, when applied using PTFE rollers. A new flat-plate denitrification catalyst that is easily formed using PTFE rollers is prepared. This catalyst and its preparation process possess the following superior properties:

[0030] Significantly improved roll forming performance: Through a compound system of stearic acid, HEC, PEO and dispersant, combined with precise moisture content control, the roll forming rate of paste is >99%, and can reach >99.9% in the best case. The sticking area on the roll is <1%, and can be reduced to <0.1% in the best case, fundamentally solving the problem of sticking on the roll.

[0031] (1) Product size and quality are stable and controllable: The rheological properties of the paste are optimized, and the thickness of the plate after rolling is uniform and controllable (0.65mm~0.75mm). The thickness uniformity is good, and the molding yield is significantly improved.

[0032] (2) Stable and excellent wear resistance: The synergistic effect of the additives makes the wear resistance stable at 120~150mg / 100r, which is far superior to the conventional formula, and greatly improves the service life and wear resistance of the catalyst. Detailed Implementation

[0033] Example 1

[0034] This embodiment describes a flat-plate denitrification catalyst and its preparation method, the method comprising the following steps:

[0035] Step 1: With a total mass of 100 parts for titanium dioxide and titanium molybdenum powder, put the titanium dioxide and titanium molybdenum powder into a mixer and dry mix for 10 minutes until they are evenly mixed.

[0036] Step 2: Dissolve ammonium metavanadate and monoethanolamine in hot water, and dissolve ammonium molybdate in cold water. Mix and stir for 30 min to obtain the active component solution.

[0037] Step 3: Add the active component solution to the mixed powder, stir evenly, and add ammonia water to adjust the pH of the system to 8.0-8.6;

[0038] Step 4: Add glass fiber and kaolin, and continue mixing for 30 minutes to ensure that the fiber and filler are fully and evenly dispersed.

[0039] Step 5: Add 0.8 parts hydroxyethyl cellulose, 0.3 parts polyethylene oxide and 2.0 parts stearic acid in two batches, with an interval of 5 minutes between each batch. Stir well and control the moisture content of the paste to be 27.0% to 29.0% and the pH of the paste to be 8.0 to 8.6.

[0040] Step Six: Seal and age the paste for 24 hours to ensure uniform distribution of moisture and additives and eliminate internal stress;

[0041] Step 7: After aging, use a rotary granulator to granulate the material and feed the granules into PTFE-coated rollers for rolling and molding.

[0042] Step 8: After segmented drying and calcination, the flat-plate denitrification catalyst product is obtained, denoted as Cat-1.

[0043] Example 2

[0044] This embodiment provides a flat-plate denitrification catalyst and its preparation method, the method comprising the following steps:

[0045] Step 1: With a total mass of 100 parts for titanium dioxide and titanium molybdenum powder, put the titanium dioxide and titanium molybdenum powder into a mixer and dry mix for 8 minutes until evenly mixed.

[0046] Step 2: Dissolve ammonium metavanadate and monoethanolamine in hot water, and dissolve ammonium molybdate in cold water. Mix and stir for 25 minutes to obtain the active component solution.

[0047] Step 3: Add the active component solution to the mixed powder, stir evenly, and add ammonia water to adjust the pH of the system to 8.0-8.6;

[0048] Step 4: Add glass fiber and kaolin, and continue mixing for 35 minutes to ensure that the fiber and filler are fully and evenly dispersed.

[0049] Step 5: Add 0.8 parts hydroxyethyl cellulose, 0.3 parts polyethylene oxide, 2.0 parts stearic acid and 0.5 parts dispersant in two batches, with an interval of 7 minutes between each batch. Stir well and control the moisture content of the paste to be 27.0% to 29.0% and the pH of the paste to be 8.0 to 8.6.

[0050] Step Six: Seal and age the paste for 24 hours to ensure uniform distribution of moisture and additives and eliminate internal stress;

[0051] Step 7: After aging, use a rotary granulator to granulate the material and feed the granules into PTFE-coated rollers for rolling and molding.

[0052] Step 8: After segmented drying and calcination, the flat-plate denitrification catalyst product is obtained, denoted as Cat-2.

[0053] Example 3

[0054] This embodiment provides a flat-plate denitrification catalyst and its preparation method, the method comprising the following steps:

[0055] Step 1: With a total mass of 100 parts for titanium dioxide and titanium molybdenum powder, put the titanium dioxide and titanium molybdenum powder into a mixer and dry mix for 10 minutes until they are evenly mixed.

[0056] Step 2: Dissolve ammonium metavanadate and monoethanolamine in hot water, and dissolve ammonium molybdate in cold water. Mix and stir for 40 min to obtain the active component solution.

[0057] Step 3: Add the active component solution to the mixed powder, stir evenly, and add ammonia water to adjust the pH of the system to 8.0-8.6;

[0058] Step 4: Add glass fiber and kaolin, and continue mixing for 25 minutes to ensure that the fiber and filler are fully and evenly dispersed.

[0059] Step 5: Add 0.8 parts hydroxyethyl cellulose, 0.3 parts polyethylene oxide and 1.0 parts stearic acid in two batches, with an interval of 6 minutes between each batch. Stir well and control the moisture content of the paste to be 27.0% to 29.0% and the pH of the paste to be 8.0 to 8.6.

[0060] Step Six: Seal and age the paste for 24 hours to ensure uniform distribution of moisture and additives and eliminate internal stress;

[0061] Step 7: After aging, use a rotary granulator to granulate the material and feed the granules into PTFE-coated rollers for rolling and molding.

[0062] Step 8: After segmented drying and calcination, the flat-plate denitrification catalyst product is obtained, denoted as Cat-3.

[0063] Example 4

[0064] This embodiment provides a flat-plate denitrification catalyst and its preparation method, the method comprising the following steps:

[0065] Step 1: With a total mass of 100 parts for titanium dioxide and titanium molybdenum powder, put the titanium dioxide and titanium molybdenum powder into a mixer and dry mix for 15 minutes until they are evenly mixed.

[0066] Step 2: Dissolve ammonium metavanadate and monoethanolamine in hot water, and dissolve ammonium molybdate in cold water. Mix and stir for 20 minutes to obtain the active component solution.

[0067] Step 3: Add the active component solution to the mixed powder, stir evenly, and add ammonia water to adjust the pH of the system to 8.0-8.6;

[0068] Step 4: Add glass fiber and kaolin, and continue mixing for 40 minutes to ensure that the fiber and filler are fully and evenly dispersed.

[0069] Step 5: Add 0.6 parts hydroxyethyl cellulose, 0.3 parts polyethylene oxide, and 2.0 parts stearic acid in two batches, with an interval of 6 minutes between each addition. Stir well to ensure the moisture content of the paste is 27.0%–29.0% and the pH is 8.0–8.6. Step 6: Seal and age the paste for 24 hours to ensure uniform distribution of moisture and additives and to eliminate internal stress.

[0070] Step 7: After aging, use a rotary granulator to granulate the material and feed the granules into PTFE-coated rollers for rolling and molding.

[0071] Step 8: After segmented drying and calcination, the flat-plate denitrification catalyst product is obtained, denoted as Cat-4.

[0072] Example 5

[0073] This embodiment provides a flat-plate denitrification catalyst and its preparation method, the method comprising the following steps:

[0074] Step 1: With a total mass of 100 parts for titanium dioxide and titanium molybdenum powder, put the titanium dioxide and titanium molybdenum powder into a mixer and dry mix for 12 minutes until they are evenly mixed.

[0075] Step 2: Dissolve ammonium metavanadate and monoethanolamine in hot water, and dissolve ammonium molybdate in cold water. Mix and stir for 35 min to obtain the active component solution.

[0076] Step 3: Add the active component solution to the mixed powder, stir evenly, and add ammonia water to adjust the pH of the system to 8.0-8.6;

[0077] Step 4: Add glass fiber and kaolin, and continue mixing for 25 minutes to ensure that the fiber and filler are fully and evenly dispersed.

[0078] Step 5: Add 0.6 parts hydroxyethyl cellulose, 0.4 parts polyethylene oxide, and 2.0 parts stearic acid in two batches, with a 6-minute interval between each batch. Stir well to ensure the moisture content of the paste is 27.0%–29.0% and the pH is 8.0–8.6. Step 6: Seal and age the paste for 24 hours to ensure uniform distribution of moisture and additives and to eliminate internal stress.

[0079] Step Six: Seal and age the paste for 24 hours to ensure uniform distribution of moisture and additives and eliminate internal stress;

[0080] Step 7: After aging, use a rotary granulator to granulate the material and feed the granules into PTFE-coated rollers for rolling and molding.

[0081] Step 8: After segmented drying and calcination, the flat-plate denitrification catalyst product is obtained, denoted as Cat-5.

[0082] Comparative Example 1

[0083] This comparative example provides a flat-plate denitrification catalyst, the preparation method of which is basically the same as that of Example 1, the only difference being that the output moisture content is controlled at 32%, and the remaining components are completely consistent with the process conditions. The specific steps are as follows:

[0084] Step 1: With a total mass of 100 parts for titanium dioxide and titanium molybdenum powder, put the titanium dioxide and titanium molybdenum powder into a mixer and dry mix for 10 minutes until they are evenly mixed.

[0085] Step 2: Dissolve ammonium metavanadate and monoethanolamine in hot water, and dissolve ammonium molybdate in cold water. Mix and stir for 30 min to obtain the active component solution.

[0086] Step 3: Add the active component solution to the mixed powder, stir evenly, and add ammonia water to adjust the pH of the system to 8.0-8.6;

[0087] Step 4: Add glass fiber and kaolin, and continue mixing for 30 minutes to ensure that the fiber and filler are fully and evenly dispersed.

[0088] Step 5: Add 0.8 parts hydroxyethyl cellulose, 0.3 parts polyethylene oxide and 2.0 parts stearic acid in two batches, with an interval of 5 minutes between each batch. Stir well and control the moisture content of the paste to be 27.0% to 29.0% and the pH of the paste to be 8.0 to 8.6.

[0089] Step Six: Seal the ointment and let it age for 24 hours;

[0090] Step 7: Granulation using a rotary granulator, followed by PTFE-coated roller pressing and molding;

[0091] Step 8: Dry and calcine to obtain the comparative catalyst, denoted as Cat-D1.

[0092] Comparative Example 2

[0093] This comparative example provides a plate-type denitrification catalyst, the preparation method of which is basically the same as that of Example 1, except that stearic acid is not added, and the remaining components and process conditions are completely consistent. The specific steps are as follows:

[0094] Step 1: With a total mass of 100 parts for titanium dioxide and titanium molybdenum powder, put the titanium dioxide and titanium molybdenum powder into a mixer and dry mix for 10 minutes until they are evenly mixed.

[0095] Step 2: Dissolve ammonium metavanadate and monoethanolamine in hot water, and dissolve ammonium molybdate in cold water. Mix and stir for 30 min to obtain the active component solution.

[0096] Step 3: Add the active component solution to the mixed powder, stir evenly, and add ammonia water to adjust the pH of the system to 8.0-8.6;

[0097] Step 4: Add glass fiber and kaolin, and continue mixing for 30 minutes to ensure that the fiber and filler are fully and evenly dispersed.

[0098] Step 5: Add 0.8 parts hydroxyethyl cellulose, 0.3 parts polyethylene oxide and 2.0 parts stearic acid in two batches, with an interval of 5 minutes between each batch. Stir well and control the moisture content of the paste to be 27.0% to 29.0% and the pH of the paste to be 8.0 to 8.6.

[0099] Step Six: Seal the ointment and let it age for 24 hours;

[0100] Step 7: Granulation using a rotary granulator, followed by PTFE-coated roller pressing and molding;

[0101] Step 8: Dry and calcine to obtain the comparative catalyst, denoted as Cat-D2.

[0102] Test case

[0103] The Cat-1 to Cat-5 prepared in Examples 1 to 5 and the Cat-D1 to Cat-2 prepared in Comparative Examples 1 to 2 were subjected to roll forming tests to test the web area, roller adhesion, and wear resistance. The results are shown in Table 1 below.

[0104]

Claims

1. A plate-type denitrification catalyst, characterized in that: The catalyst comprises a plate-shaped catalyst unit made of paste; The ointment, by weight, consists of the following components: The composition includes: 70-80 parts titanium dioxide, 20-30 parts titanium-molybdenum composite powder, 1.5-2.5 parts stearic acid, 0.587-0.625 parts ammonium metavanadate, 1.07-1.15 parts ammonium molybdate, 3.1 parts glass fiber, 5.4 parts kaolin, 0.3-1.1 parts hydroxyethyl cellulose, 0.4-0.8 parts polyethylene oxide, 0.3-0.6 parts dispersant, and 60 parts water.

2. The flat-plate denitrification catalyst according to claim 1, characterized in that: The ointment is prepared by a method comprising the following steps: Step S1: Take titanium dioxide, titanium molybdenum composite powder and stearic acid according to the ratio, put them into a mixer and dry mix for 5 to 15 minutes. Step S2: Dissolve ammonium metavanadate in deionized water containing monoethanolamine at a temperature of 85℃~100℃, and dissolve ammonium molybdate in deionized water at room temperature. Mix the two solutions to obtain the active solution. The amount of monoethanolamine used is sufficient to completely dissolve ammonium metavanadate. Step S3: Add the active liquid obtained in step S2 into a mixer and mix for 20-40 minutes. Add ammonia water to adjust the pH of the system to 8.0-8.

6. Step S4: Add glass fiber and kaolin, and continue mixing for 20-40 minutes; Step S5: Add hydroxyethyl cellulose, polyethylene oxide and dispersant while stirring. The addition method is to add them in two equal parts. Add half of the total amount in the first part, and add the remaining half after an interval of 5 to 10 minutes. Continue stirring until uniform. Control the moisture content of the discharged paste to be 27.0% to 29.0% and the pH to be 8.0 to 8.

6. Step S6: Seal and age to obtain the ointment.

3. A method for preparing a planar denitrification catalyst as described in claim 1 or 2, characterized in that: Includes the following steps: Step A: The paste described in claim 1 or 2 is aged for 20 to 28 hours and then rotary granulated to obtain granulated material, which is then placed at the inlet of the coating roller. Step B: The coating roller rolls the granulated material to form a flat wet blank. Step C: The flat wet blank is dried at 60℃~110℃ for 2~3 hours, and then calcined at 500℃~5500℃ for 2~3 hours to obtain a flat denitrification catalyst.

4. The method for preparing the plate-type denitrification catalyst according to claim 3, characterized in that, The coating roller is a polytetrafluoroethylene coating roller.

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