Preparation method of dust removal and catalytic oxidation integrated filter material

Abstract

The invention discloses a preparation method of a dust removal and catalytic oxidation integrated filter material, belongs to the field of flue gas purification, and particularly relates to a preparation method of a dust removal and catalytic oxidation integrated filter material. The invention aims to solve the technical problems of single filter material function, poor sulfur resistance, low adhesive force, low heat utilization efficiency and high process energy consumption in the existing industrial flue gas treatment. The preparation method comprises the following steps: firstly, preparing catalytic slurry by combining binder regulation and a ball milling process; according to the present invention, the cordierite carrier is used as the carrier, the cordierite carrier is uniformly loaded by using the rotary spray coating technology, the prepared integrated filter material completely converts CO into CO2 at the temperature of 150 DEG C, the conversion rate of VOCs reaches 92-98%, and the conversion rate of CO can be maintained at 85-90% under the SO2-containing condition. The integrated filter material is high in heat recovery rate in the application process, so that part of fossil fuel is replaced, and the integrated filter material is suitable for the oxidation dust removal process of energetic gas containing CO / VOCs and the like in the actual industrial process.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of flue gas purification, and particularly relates to a preparation method of a dust removal and catalytic oxidation integrated filter material. BACKGROUND

[0002] Carbon monoxide (CO) and volatile organic compounds (VOCs) in industrial flue gas are typical gaseous pollutants. Simultaneous purification and recovery of chemical heat energy released by the reaction are important technical directions for energy saving and consumption reduction in flue gas treatment process. At present, catalytic oxidation technology is generally used for the treatment of CO and VOCs, which can achieve high purification efficiency, but in actual industrial application, an independent catalytic reaction unit often needs to be added, resulting in equipment redundancy, process extension and significant increase in energy consumption.

[0003] The coupling of CO catalytic oxidation and dust removal on the same filter material can construct a new integrated treatment technology with short process and low energy consumption, which can not only simplify the system structure, but also utilize the heat released by CO oxidation to reduce external energy input, and has significant technical and economic advantages. In the field of multi-pollutant synergistic control of flue gas, the integrated technology of denitration (NO x ) and dust removal has been relatively mature and widely used. However, the coupling of CO catalytic oxidation and dust removal still faces significant challenges, and research and application are relatively lacking. This is mainly because there are fundamental differences between CO catalytic oxidation catalyst and denitration catalyst in active components, carrier properties and reaction mechanism, and the required reaction microenvironment and preparation process are completely different, which cannot directly use or copy the existing denitration and dust removal synergistic technology route.

[0004] The core difficulty of realizing CO oxidation-dust removal integration is how to make the active components of CO catalyst highly dispersed and stably loaded on the surface of the filter material, which can withstand the complex components (such as SO2) of industrial flue gas and frequent pulse cleaning operation while ensuring excellent low-temperature catalytic activity. Thin-layer catalytic design (coating thickness <200 μm) and efficient heat transfer of gradient pore structure break through the bottleneck of less than 45% of heat utilization rate of traditional process. The strong coupling between the catalyst and the filter material matrix is the key to prevent the active components from falling off and maintain long-term stability, and is also the bottleneck of the current technology to industrial application. SUMMARY

[0005] The present application aims to solve the technical problems of single function of filter material, poor sulfur resistance, low adhesion, low heat utilization efficiency and high process energy consumption in the current industrial flue gas treatment, and provides a preparation method of a dust removal and catalytic oxidation integrated filter material.

[0006] The preparation method of the dust removal and catalytic oxidation integrated filter material of the present application is carried out according to the following steps:

[0007] I. Preparation of a high-stability catalytic slurry:

[0008] ①, the carrier powder, binder and deionized water are added into a ball mill for uniform mixing and ball milling to obtain a slurry; then dilute nitric acid or ammonia water is added dropwise to adjust the pH value of the slurry so that the pH value of the slurry is far from the isoelectric point of the selected carrier and the electrostatic repulsion is enhanced, the stability of the slurry is improved, and the active component is prevented from agglomeration;

[0009] The carrier powder is CeO2 or TiO2, and when the carrier powder is CeO2, the adjusted pH value of the slurry is 8-9; when the carrier powder is TiO2, the adjusted pH value of the slurry is 4-5;

[0010] The binder is silica sol, alumina sol, zirconium sol or titanium sol;

[0011] The mass ratio of the binder to the carrier powder is 1:(2-3);

[0012] ②, a platinum nitrate solution is added dropwise into the slurry in ① by using a dropper, the mass of platinum element is 0.2%-5% of the mass of the carrier powder in ①, and magnetic stirring is performed for 2-3 hours; then an ammonium tungstate solution is added, the mass of tungsten element is 1%-3% of the mass of the carrier powder in ①, and then aging is performed at 40-45°C for 4-4.5 hours in a water bath; after standing and defoaming for 30-35 minutes, a uniform catalytic slurry is obtained;

[0013] II. Preparation of a ceramic filter cartridge base:

[0014] ①, immerse the cordierite filter cartridge completely in a hydrofluoric acid solution, and perform ultrasonic oscillation etching at 40-45°C for 60-65 minutes to etch a porous structure on the surface of the cordierite filter cartridge;

[0015] ②, immediately immerse the etched cordierite filter cartridge into a deionized water washing tank for washing until the pH value of the washing water is 6.5-7, and then place the cordierite filter cartridge in a hot air circulation drying box for drying to obtain a porous filter cartridge;

[0016] III. Coating of the catalytic slurry:

[0017] Preheat the porous filter cartridge to 80°C±2°C to reduce the surface tension of the slurry; then load the catalytic slurry prepared in step I on the surface of the porous filter cartridge by a rotary spray coating method, and the porous filter cartridge is kept rotating during coating;

[0018] IV. Drying and calcination: dry the sample obtained in step III, and then transfer the dried sample into a box furnace, and calcine the sample at 500-550°C in an air atmosphere for 2-3 hours to form a high-dispersion and high-adhesion active site protection layer, and finally obtain a dust removal and catalytic oxidation integrated filter material.

[0019] In step one, this invention combines binder control and ball milling to control the slurry particle size to 1.5 μm~2.5 μm, obtaining a highly stable catalytic slurry with a solid content of 25%~30% and a viscosity of 0.01~0.02 Pa·s. Then, in step two, the filter cartridge substrate is etched with hydrofluoric acid to form a three-dimensional porous structure, and a rotary spray coating technique is used to achieve uniform loading of the cordierite carrier. The resulting integrated filter media exhibits complete CO conversion to CO2 at 150℃, and a VOCs conversion rate of 92%~98% (converted to carbon dioxide and water) at 150℃, while maintaining SO2 content (30~50 mg / m³). 3 Under these conditions, the CO conversion rate can still be maintained at 85%~90%; the particulate matter removal rate reaches 99.9%; the matrix ring compressive strength of the porous filter cartridge is 0.35MPa~0.4MPa, and there is no peeling after rotary spray coating; the porosity of the porous filter cartridge reaches 30%~60%; the heat recovery rate of the integrated filter material reaches 75%~85% during application; CO oxidation can raise the flue gas temperature by 30~35℃, thereby replacing part of the fossil fuels and significantly reducing the external heating demand. It is suitable for the oxidation and dust removal process of energetic gases such as CO / VOCs in actual industrial processes.

[0020] The beneficial effects of this invention are:

[0021] (1) This invention improves the adsorption and binding performance between the catalytic slurry and the substrate by adjusting the pH of the slurry; by controlling the pH of the slurry system to keep it away from the isoelectric point of the carrier, it can effectively avoid agglomeration, promote dispersion, and enhance coating uniformity and bonding strength. At a low temperature of 150℃, it achieves complete CO conversion, a VOCs conversion rate of 95%, and a particulate matter removal rate of 99.9%, significantly better than commercial Pt / Ti catalysts (≤80% conversion rate), solving the efficiency loss and energy consumption problems caused by the step-by-step processing of traditional processes;

[0022] (2) This invention forms a cordierite matrix with a gradient porosity of 30-60% by hydrofluoric acid etching (ring crush strength ≥0.35MPa), combined with rotary spray directional coating (atomization pressure 0.6MPa, rotation speed 150rpm), and the catalytic slurry (particle size ≤1.91μm) deeply penetrates into the matrix pores, which can achieve 10,000 pulse cleaning cycles without peeling; compared with the traditional impregnation method (peeling rate >5%) and powder adhesion method (peeling rate >18%), this design ensures the long-term stability of the active components and avoids the performance degradation caused by industrial cleaning;

[0023] (3) The integrated filter material prepared by this invention utilizes the exothermic reaction of CO oxidation (282.98 kJ / mol) to achieve a self-heating cycle with a heat recovery rate of 80% and a flue gas temperature rise of 31.3°C, replacing part of the external fossil fuel heating and reducing energy consumption by >50%. This advantage stems from the efficient heat transfer of the thin-layer catalytic design (coating thickness <200 μm) and gradient pore structure, breaking through the bottleneck of less than 45% heat utilization rate in traditional processes, and providing an economical ultra-low emission path for high-emission industries;

[0024] (4) Excellent sulfur resistance and long-term durability: The integrated filter media prepared by this invention has excellent sulfur resistance (30 mg / m³) and long-term durability. 3 Under harsh operating conditions, the filter media maintains a CO conversion rate of 88.7%, and the decay rate is less than 8% after 8000 hours of continuous operation, which is more than 50% higher than that of traditional filter media (sulfur poisoning decay >15%). Its anti-sulfur mechanism relies on the enhanced surface hydroxyl acidity and asymmetric oxygen site activation of amorphous tungsten oxide to form a double active protective layer to inhibit SO2 competitive adsorption, which solves the industry difficulty of sulfur poisoning of precious metal catalysts and extends the filter media life by more than 2 times. Attached Figure Description

[0025] Figure 1 This is a photograph of the actual filter material for dust removal and catalytic oxidation prepared in Experiment 1.

[0026] Figure 2 This is a graph showing the CO oxidation conversion rate of integrated filter media with different loading capacities in Experiment 4;

[0027] Figure 3 This is a graph showing the VOCs oxidation conversion rate of the integrated filter media with different loading capacities in Experiment 5;

[0028] Figure 4 This is a graph showing the CO conversion rate of the integrated filter media at different space velocities in Experiment 6;

[0029] Figure 5 This is a graph showing the VOCs conversion rate of the integrated filter media at different space velocities in Experiment 7;

[0030] Figure 6 This is a graph showing the CO conversion rate of the integrated filter media under conditions of 50 ppm SO2 presence.

[0031] Figure 7 These are TEM images of the integrated filter media before and after the CO catalytic oxidation performance test conducted in Experiment 4. Detailed Implementation

[0032] Specific Implementation Method 1: This implementation method is a preparation method of an integrated dust removal and catalytic oxidation filter material, specifically carried out according to the following steps:

[0033] I. Preparation of Highly Stable Catalytic Slurry:

[0034] ① Add the carrier powder, binder and deionized water together into a ball mill and mix and ball mill evenly to obtain a slurry; then add dilute nitric acid or ammonia to adjust the pH value of the slurry so that the pH value of the slurry is far away from the isoelectric point of the selected carrier and enhances the electrostatic repulsion effect, improves the stability of the slurry and prevents the agglomeration of active components.

[0035] The carrier powder is CeO2 or TiO2, and when the carrier powder is CeO2, the pH value of the slurry is adjusted to 8-9; when the carrier powder is TiO2, the pH value of the slurry is adjusted to 4-5.

[0036] The binder is silica sol, aluminum sol, zirconium sol, or titanium sol;

[0037] The mass ratio of the binder to the carrier powder is 1:(2~3);

[0038] ② Add platinum nitrate solution dropwise to the slurry in ① using a dropper, wherein the mass of platinum is 0.2%~5% of the mass of the carrier powder in ①, and stir magnetically for 2h~3h; then add ammonium tungstate solution, wherein the mass of tungsten is 1%~3% of the mass of the carrier powder in ①, and then age in a water bath at 40℃~45℃ for 4h~4.5h; let stand to defoam for 30min~35min to obtain a homogeneous catalytic slurry;

[0039] II. Preparation of ceramic filter cartridge substrate:

[0040] ① The cordierite filter cartridge is completely immersed in hydrofluoric acid solution and ultrasonically etched at 40℃~45℃ for 60min~65min to create a porous structure on the surface of the cordierite filter cartridge.

[0041] ② Immediately immerse the etched cordierite filter cartridge in a deionized water rinsing tank for rinsing until the pH of the rinsing water is 6.5~7. Then place the cordierite filter cartridge in a hot air circulating drying oven to dry, and obtain a porous filter cartridge.

[0042] III. Coating of the catalytic slurry:

[0043] The porous filter cartridge is preheated to 80℃±2℃ to reduce the surface tension of the slurry; then the catalytic slurry prepared in step one is loaded onto the surface of the porous filter cartridge (including the outer wall, inner wall and two end faces) by a rotary spray coating method, and the porous filter cartridge is kept rotating during the coating process.

[0044] IV. Drying and calcination: The sample obtained in step 3 is dried, and then the dried sample is transferred to a box furnace and calcined in air at 500℃~550℃ for 2h~3h to form a protective layer of highly dispersed and strongly adhesive active sites, and finally the integrated dust removal and catalytic oxidation filter material is obtained.

[0045] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the binder mentioned in step one ① is silica sol, aluminum sol, zirconium sol, or titanium sol, and the mass content of solids therein (for example, the solid in silica sol is SiO2) is 15%~25%. Everything else is the same as in Specific Implementation Method One.

[0046] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that the sum of the solid mass of the carrier powder and the binder in the slurry prepared in step 1 is 25% to 30%. Everything else is the same as in Specific Implementation Method 1 or 2.

[0047] Specific Implementation Method Four: This implementation method differs from one of Specific Implementation Methods One to Three in that the platinum content in the platinum nitrate solution described in step one ② is 10%. Everything else is the same as in one of Specific Implementation Methods One to Three.

[0048] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method Four in that the tungsten content in the ammonium tungstate solution described in step one, step two, is 5% by mass. Everything else is the same as in Specific Implementation Method Four.

[0049] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method Five in that the mass concentration of the hydrofluoric acid solution mentioned in step two① is 10%. Everything else is the same as in Specific Implementation Method Five.

[0050] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Six in that the flow rate of deionized water rinsing in step two ② is 5 L / min. Everything else is the same as in Specific Implementation Method Six.

[0051] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Seven in that the drying temperature in step two ② is 110℃ and the time is 2 hours. Everything else is the same as in Specific Implementation Method Seven.

[0052] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method Eight in that the pressure during rotary spray coating in step three is 0.6 MPa, the rotation speed of the porous filter cartridge during coating is 100 rpm to 200 rpm, and the loading amount is 10% to 30%. The numerator of the loading amount is the sum of the masses of the carrier powder, tungsten element, and platinum element, and the denominator is the mass of the porous filter cartridge. Everything else is the same as in Specific Implementation Method Eight.

[0053] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method Nine in that: the drying temperature in step four is 60°C; and the heating rate before calcination is 5°C·min. -1 Everything else is the same as in specific implementation method nine.

[0054] The invention was verified using the following experiments:

[0055] Experiment 1: This experiment demonstrates a method for preparing an integrated dust removal and catalytic oxidation filter material, specifically carried out according to the following steps:

[0056] I. Preparation of Highly Stable Catalytic Slurry:

[0057] ① Add the carrier powder, binder and deionized water together into a ball mill and mix and ball mill evenly to obtain a slurry; then add dilute nitric acid or ammonia to adjust the pH of the slurry to 4.5 so that the pH of the slurry is far away from the isoelectric point of the selected carrier and enhances the electrostatic repulsion effect, improves the stability of the slurry and prevents the agglomeration of active components.

[0058] The carrier powder is TiO2;

[0059] The binder is silica sol, and the mass content of SiO2 therein is 20%.

[0060] The mass ratio of the binder to the carrier powder is 1:2;

[0061] The total mass of the solids in the carrier powder and binder contained in the slurry prepared in step one is 30%.

[0062] ② Add platinum nitrate solution dropwise to the slurry in ① using a dropper, wherein the mass of platinum is 3% of the mass of the carrier powder in ①, and stir magnetically for 2 hours; then add ammonium tungstate solution, wherein the mass of tungsten is 3% of the mass of the carrier powder in ①, and then age in a water bath at 40℃ for 4 hours; let stand to defoam for 30-35 minutes to obtain a homogeneous catalytic slurry, and measure its viscosity at 25℃ using a rotational viscometer to be ≤0.025 Pa·s;

[0063] The platinum nitrate solution contains 10% platinum by mass.

[0064] The ammonium tungstate solution contains 5% tungsten by mass.

[0065] II. Preparation of ceramic filter cartridge substrate:

[0066] ① Place the cordierite filter cartridge (Mg2Al4Si5O) 18 Completely immersed in hydrofluoric acid solution, with the liquid level 20 mm above the top of the ultrafiltration cartridge, ultrasonically etched at 40°C for 60 min, a porous structure was etched on the surface of the cordierite filter cartridge. The etch depth was tested to be 200 μm, forming a gradient pore area of ​​50%.

[0067] The hydrofluoric acid solution has a mass concentration of 10%.

[0068] ② Immediately immerse the etched cordierite filter cartridge in a deionized water rinsing tank for rinsing at a flow rate of 5L / min until the pH of the rinsing water reaches 7. Then place the cordierite filter cartridge in a hot air circulating drying oven to dry at a temperature of 110℃ for 2 hours to obtain a porous filter cartridge.

[0069] III. Coating of the catalytic slurry;

[0070] The porous filter cartridge is preheated to 80°C to reduce the surface tension of the slurry. Then, the catalytic slurry prepared in step one is loaded onto the surface of the porous filter cartridge (including the outer wall, inner wall, and two end faces) by a rotary spray coating method. The porous filter cartridge is kept rotating during the coating process. The pressure during rotary spray coating is 0.6 MPa, the rotation speed of the porous filter cartridge is 200 rpm, and the loading is 10%. The numerator of the loading is the sum of the masses of the carrier powder, tungsten element, and platinum element, and the denominator is the mass of the porous filter cartridge.

[0071] IV. Drying and Calcination: Dry the sample obtained in step three at a temperature of 60℃, then transfer the dried sample to a box furnace at a heating rate of 5℃·min. -1 The material is calcined in air at 500°C for 2 hours to form a protective layer of highly dispersed and strongly adhesive active sites, ultimately yielding an integrated dust removal and catalytic oxidation filter material. A photograph of the actual product is shown below. Figure 1 As shown, it is denoted as PtWTi-1.

[0072] Experiment 2: This experiment differs from Experiment 1 in that the loading rate in step 3 is 20%, and the resulting integrated filter media is denoted as PtWTi-3. Everything else is the same as Experiment 1.

[0073] Experiment 3: This experiment differs from Experiment 1 in that the loading rate in step 3 is 30%, and the resulting integrated filter media is denoted as PtWTi-4. Everything else is the same as Experiment 1.

[0074] The oxidation performance of integrated filter media is tested through the following tests:

[0075] Experiment 4: CO Catalytic Oxidation Performance Test: The integrated filter media prepared in Experiments 1 to 3 above were vertically filled into stainless steel reactors and sealed. Simulated industrial flue gas (volume fraction: 1% CO + 20% O2 + 79% N2) was introduced and the space velocity was controlled at 30,000 h⁻¹. -1 (i.e., 3W); the temperature was increased from room temperature to 240℃ at a programmed rate of 5℃ / min, and the CO concentration at the outlet was monitored in real time by online gas chromatography (TCD detector). A temperature-activity curve was plotted, such as... Figure 2 As shown, Figure 2The graph shows the CO oxidation conversion rate of integrated filter media with different loading capacities. It can be found that the loading capacity of 10wt% (corresponding to Experiment 1) is the best, and CO is completely converted into CO2 at 150℃.

[0076] Experiment 5: VOCs Catalytic Oxidation Performance Test: The integrated filter media prepared in Experiments 1 to 3 above were vertically filled into stainless steel reactors and sealed. Simulated industrial flue gas (100 ppm Toluene + 21% O2 + 79% N2) was introduced, and the space velocity was controlled at 30,000 h⁻¹. -1 (i.e., 3W); the temperature was increased from room temperature to 300℃ at a programmed rate of 5℃ / min, and the Toluene concentration at the outlet was monitored in real time by online gas chromatography (TCD detector). A temperature-activity curve was plotted, as shown below. Figure 3 As shown, Figure 3 The graph shows the oxidation conversion rate of VOCs in integrated filter media with different loading capacities. It can be found that the loading capacity of 10wt% has the best effect, with a VOCs conversion rate of 95% at 150℃.

[0077] Experiment Six: This experiment differs from Experiment Four in that the filter media used is PtWTi-1 prepared in Experiment One, and the space velocity is controlled at 30,000 h⁻¹. -1 (i.e., 3W), 6W, and 9W were compared, and temperature-activity curves were plotted, such as... Figure 4 As shown, Figure 4 The graph shows the CO conversion rate of the integrated filter media at different air velocities, and it can be seen that the effect is best at 6 W air velocity.

[0078] Experiment 7: This experiment differs from Experiment 5 in that the filter media used is PtWTi-1 prepared in Experiment 1, and the space velocity is controlled at 30000 h⁻¹. -1 (i.e., 3W), 6W, and 9W were compared, and temperature-activity curves were plotted, such as... Figure 5 As shown, Figure 5 The graph shows the VOCs conversion rate of the integrated filter media at different air velocities. It can be seen that the effect is best at an air velocity of 3w.

[0079] Sulfur resistance test: The integrated filter media prepared in Experiment 1 was vertically packed into a stainless steel reactor and sealed. Simulated industrial flue gas (50ppm SO2 + 1% CO + 20% O2 + 79% N2) was introduced, and the space velocity was controlled at 30,000 h⁻¹. -1 (i.e., 3W); the temperature was increased from room temperature to 240℃ at a programmed rate of 5℃ / min, and the concentrations of CO and SO2 at the outlet were monitored in real time by online gas chromatography (TCD detector). Temperature-activity curves were plotted, such as... Figure 6 As shown, Figure 6The graph shows the CO conversion rate of the integrated filter media under the condition of 50ppm SO2 presence. It can be seen that it has excellent sulfur resistance and maintains a CO conversion rate of 88.7% under SO2 presence.

[0080] Mechanical stability test: High-frequency mechanical stress loading provides empirical support for the industrial life of filter media. The test results confirm that the filter media prepared in Experiment 1 did not fall off after 10,000 cleaning cycles, which is a significant improvement compared with the traditional impregnation method (fall-off rate > 5%) and powder adhesion method (fall-off rate > 18%).

[0081] Figure 7 These are TEM images of the integrated filter media (corresponding to the filter media in Experiment 1) before and after the CO catalytic oxidation performance test in Experiment 4. Figure a is before the test, and Figure b is after the test. It can be seen that there is no obvious change in the morphology of the filter media before and after the test, and no shedding occurs.

[0082] Industrial process heat utilization rate test (see Table 1): The integrated filter material prepared in Experiment 1 was placed in two SCR reactors (a and b). By testing the temperature of the flue gas at the outlets before and after the test, it was found that the heat released by CO oxidation can achieve a self-heating cycle with a heat recovery rate of 80% and a flue gas temperature rise of 31.3℃, breaking through the bottleneck of less than 45% heat utilization rate of traditional processes.

[0083] Table 1 shows the inlet and outlet flue gas temperatures of the CO catalytic reactor when placed in SCR reactor a and SCR reactor b, respectively.

[0084]

[0085] Experiment 8: The difference between this experiment and Experiment 1 is that the binder mentioned in step 1① is aluminum sol, and the mass content of alumina in it is 20%. The resulting integrated filter material is denoted as PtWTi-2. Everything else is the same as Experiment 1.

[0086] Comparative Experiment: The difference between this experiment and Experiment 1 is that the cordierite filter cartridge is not etched, i.e., it is not in step two. The resulting integrated filter material is denoted as PtWTi-5. Everything else is the same as Experiment 1.

[0087] Experiment Nine: The difference between this experiment and Experiment One is that the carrier powder mentioned in step one ① is cerium dioxide, and the resulting integrated filter material is denoted as PtWTi-6. Everything else is the same as Experiment One.

[0088] The properties of the various filter media prepared above are shown in Table 2 below.

[0089] Table 2. Performance Comparison of Integrated Filter Media and Traditional Filter Media

[0090]

[0091]

[0092]

Claims

1. A method for preparing a filter material integrated with a dust removal catalytic oxidation, characterized in that The preparation method is carried out according to the following steps: I. Preparation of high stability catalytic slurry: ①, the carrier powder, binder and deionized water are added into the ball mill for uniform mixing and ball milling to obtain a slurry; then, dilute nitric acid or ammonia water is added dropwise to adjust the pH value of the slurry so that the pH value of the slurry is far away from the isoelectric point of the selected carrier and the electrostatic repulsion is enhanced, the stability of the slurry is improved, and the active component is prevented from agglomeration; The carrier powder is CeO2 or TiO2, and when the carrier powder is CeO2, the adjusted slurry pH value is 8-9; when the carrier powder is TiO2, the adjusted slurry pH value is 4-5; The binder is silica sol, alumina sol, zirconium sol or titanium sol; The mass ratio of the binder to the carrier powder is 1:(2-3); ②, a pipette is used to add platinum nitrate solution dropwise into the slurry in ①, wherein the mass of platinum element is 0.2%-5% of the mass of the carrier powder in ①, and magnetic stirring is carried out for 2-3 hours; then, ammonium tungstate solution is added, wherein the mass of tungsten element is 1%-3% of the mass of the carrier powder in ①, and then aging is carried out at 40-45°C for 4-4.5 hours; after standing and defoaming for 30-35 minutes, a uniform catalytic slurry is obtained; II. Preparation of ceramic filter cartridge base: ①, the cordierite filter cartridge is completely immersed in a hydrofluoric acid solution, and a porous structure is etched on the surface of the cordierite filter cartridge by ultrasonic oscillation etching at 40-45°C for 60-65 minutes; ②, the etched cordierite filter cartridge is immediately immersed in a deionized water washing tank for washing until the pH value of the washing water is 6.5-7, and then the cordierite filter cartridge is placed in a hot air circulation drying box for drying to obtain a porous filter cartridge; III. Coating of catalytic slurry: The porous filter cartridge is preheated to 80°C±2°C to reduce the surface tension of the slurry; then, the catalytic slurry prepared in step I is loaded on the surface of the porous filter cartridge by a rotary spray coating method, and the porous filter cartridge is kept rotating during coating; IV. Drying and calcination: the sample obtained in step III is dried, and then the dried sample is transferred to a box furnace for calcination at 500-550°C in an air atmosphere for 2-3 hours to form a high-dispersion and strong-adhesion active site protection layer, and finally a dust removal and catalytic oxidation integrated filter material is obtained.

2. The method of claim 1, wherein the method further comprises the step of: The binder in step I ① is silica sol, alumina sol, zirconium sol or titanium sol, and the solid mass content therein is 15%-25%. ​ 3. The method of claim 2, wherein the method further comprises the step of: The sum of the solid mass of the carrier powder and the binder in the slurry prepared in step I is 25%-30%. ​ 4. The method of claim 1, wherein the method further comprises the step of: 4-1) drying the filter material at a temperature of 80-120°C for 1-3 hours. The mass content of platinum in the platinum nitrate solution in step I ② is 10%.

5. The method of claim 1, wherein the method further comprises the step of: The mass content of tungsten in the ammonium tungstate solution in step I ② is 5%. ​ 6. The method of claim 1, wherein the method further comprises the step of: The mass concentration of the hydrofluoric acid solution in step II ① is 10%. ​ 7. The method of claim 1, wherein the method further comprises the step of: The flow rate of deionized water washing in step II ② is 5 L / min. ​ 8. The method of claim 1, wherein the method further comprises the step of: 8.

1. coating the filter material with a catalytic oxidation coating. The drying temperature in step II ② is 110°C, and the time is 2 hours.

9. The method of claim 1, wherein the method further comprises the step of: The pressure during rotary spray coating in step III is 0.6 MPa, the rotation speed of the porous filter cartridge during coating is 100-200 rpm, and the loading amount is 10%-30%. ​ 10. The method of claim 1, wherein the method further comprises the step of:

10. A method of preparing a catalytic oxidation and dust removal integrated filter material according to claim 1, characterized in that The drying temperature in step four is 60°C; the temperature increase rate before calcination is 5°C / min -1 .

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