A high-strength, large-size fiber filter tube and its preparation method

Abstract

This invention discloses a high-strength, large-size fiber filter tube and its preparation method, belonging to the field of integrated ceramic membrane technology for flue gas dust removal and denitrification. This invention achieves high flexural strength by repeatedly optimizing and recombining the formula and employing traditional extrusion methods while maintaining the binder coating. Low-temperature sintering technology is used to ensure the product's high flexural strength. An inclined loading method utilizes the characteristics of mechanical forces to effectively disperse the shrinkage resistance of the large component blank during firing, avoiding cracking caused by high shrinkage resistance. The use of an inner circular alumina sleeve loading method effectively supports the product during high-temperature softening, preventing collapse and deformation, and ensuring the roundness of the large component.

Description

Technical Field

[0001] This invention belongs to the field of integrated ceramic membrane technology for flue gas dust removal and denitrification, and more specifically, relates to a high-strength, large-size fiber filter tube and its preparation method. Background Technology

[0002] In industrial development and production processes, nitrogen oxides and particulate matter are among the major air pollutants. With the popularization of environmental protection concepts such as low-carbon economy and energy conservation and emission reduction, integrated dust removal and denitrification technology is being used more and more widely. Therefore, the emergence of integrated denitrification and dust removal equipment can greatly reduce pollutant emissions and protect the environment.

[0003] The integrated denitrification and dust removal equipment mainly consists of a denitrification catalyst layer, a dust removal layer, and a support layer. The denitrification catalyst layer uses SCR (Selective Catalytic Reduction) technology to convert nitrogen oxides into harmless nitrogen and water, achieving denitrification. The dust removal layer uses electrostatic precipitators, bag filters, or electrostatic precipitators to treat particulate matter. The support layer supports the denitrification catalyst layer and the dust removal layer, and also acts as a protective layer to prevent the catalyst and dust removal layer from external impacts and damage. Existing technologies address the issue of small filter element sizes and small filtration surfaces due to limitations in molding technology, resulting in high investment costs and large footprints for industrial applications. Furthermore, many commonly used filter elements on the market are made using non-sintering molding, leading to low inherent strength. During use, the pressure in the pulse backflushing process is far greater than the filtration separation pressure, causing frequent breakage due to filter element oscillation.

[0004] Integrated denitrification and dust removal equipment is a highly efficient, energy-saving, and environmentally friendly device that can simultaneously treat nitrogen oxides and particulate matter, reducing pollutant emissions and protecting the environment. With increasing environmental awareness, integrated denitrification and dust removal equipment will become increasingly widespread and one of the mainstream environmental protection equipment of the future. Integrated denitrification and dust removal fiber tubes are a new type of filter element that combines denitrification and dust removal processes, capable of simultaneously treating nitrogen oxides and particulate matter. In the future, this technology will be further developed, promoting the coordinated development of industrial production and environmental protection. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, the technical problem to be solved by the present invention is to provide a method for preparing a high-strength, large-size fiber filter tube. By optimizing and recombining the formula multiple times and using the traditional extrusion method, the product's binder coating method and low-temperature sintering technology are maintained to ensure the high bending strength of the product. Another technical problem to be solved by the present invention is to provide a high-strength, large-size fiber filter tube prepared by this method.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a high-strength, large-size fiber filter tube includes the following steps:

[0008] 1) Prepare the pre-made small materials: chopped alumina fiber: water glass: silica sol: sodium hydroxypropyl methylcellulose in the ratio of (10-15): (65-70): (6-11): (7-12): (1-2), add a certain amount of water and mix at high speed for 15-45 minutes, and obtain the production material by non-vacuum mud removal;

[0009] 2) The production material obtained in step 1) is extruded through an extruder to form flange rings and tail sealing cover plates, and cut into the required shapes. The materials are dried at 90-110℃ until the moisture content is ≤2% to obtain flange ring blanks and tail sealing cover plate blanks.

[0010] 3) The production material obtained in step 1) is extruded through an extruder to form a support blank tube. The formed support blank tube first passes through a heating and anti-deformation zone at 80-95℃ for infrared drying of the outer surface of the blank, and at the same time passes through an internal cavity rotating air guide tube at 80-95℃ with a humidity of ≤5% to heat the inner surface of the support blank tube. Then it quickly enters the cold air anti-crack zone at 20-25℃ for rapid cooling, and finally undergoes continuous microwave drying at 95-120℃ to produce a dried support blank tube.

[0011] 4) The flange blank obtained in step 2) is bonded to the front end of the support blank pipe using fire putty. After bonding, it is dried at 100-120℃ for 30-60 minutes to obtain a support blank pipe containing the bonded flange.

[0012] 5) Place the dry blank pipe with adhesive flange obtained in step 4) on an inclined support for firing. Heat from room temperature to 300℃ at a heating rate of ≤5℃ and hold for 1-2 hours. Then heat from 300℃ to 850℃ at a heating rate of ≤3℃ and hold for 1-3 hours to form a fiber tube support matrix pipe with adhesive flange.

[0013] 6) The dry blank of the tail sealing cover obtained in step 2) is sealed to the rear end of the fiber tube support matrix tube containing the adhesive flange using fire putty. After bonding, it is dried at 100-120℃ for 30-60 minutes to obtain a support matrix tube with an adhesive flange sealed at one end.

[0014] 7) Prepare a membrane suspension slurry by mixing sepiolite chopped fiber powder, zirconium-containing aluminum silicate chopped fiber powder, silica sol, polyacrylic acid, sodium carboxymethyl cellulose, ammonium metavanadate, and manganese tetroxide in the ratio of (20-30):(35-45):(20-25):(5-8):(1.5-2.8):(3-5):(3-5), adding a certain amount of water and stirring for 25-45 minutes; use a pressure air gun to evenly spray the membrane suspension slurry onto the surface of the support base tube with an adhesive flange sealed at one end to obtain a fiber tube coated wet blank tube;

[0015] 8) The fiber tube coated wet blank obtained in step 7) is air-dried at 80-100℃. After the water loss rate is ≥96%, the membrane layer is fired. The temperature is increased from room temperature to 120℃ at a heating rate of ≤5℃ and held for 1-2 hours. Then the temperature is increased from 120℃ to 400℃ at the same heating rate and held for 2-3 hours to obtain a high-strength large-size fiber filter tube.

[0016] Preferably, in step 1), the preparation process of the pre-made small material is as follows: the mixture is prepared according to the ratio of purple clay: Guangdong black mud: Wuxi white mud: borax: water = (20-40):(20-30):(13-15):(5-10):(20-30), ball-milled for 15-20 hours, and spray-dried to obtain granulated balls with a moisture content of <5%, thus obtaining the pre-made small material.

[0017] Preferably, in step 3), the dimensions of the prepared support blank through-tube are equal to the outer diameter of the membrane tube. inner diameter Length ≥ 3000mm.

[0018] Preferably, in step 1), the non-vacuum mud-making process is as follows: the mixed mud is subjected to non-vacuum mud-making into blocks through a mud-making machine, and the mud temperature is controlled to be ≤40℃ and the moisture content is 25-30%.

[0019] Preferably, in step 7), the diameter of the pressure air gun is ≥1mm, and the coating is applied to the surface of the support base tube with an adhesive flange that has a hole sealed at one end under a pressure of 0.2 to 0.5MPa, with a coating thickness of 150 to 300μm.

[0020] Preferably, in step 1), the length of the chopped alumina fibers is 2-5 mm, the borax contains ≥35% B2O3, the water glass has a solid content ≥34.2% and a modulus of 2.2-3, the silica sol has a solid content ≥40%, and the sodium hydroxypropyl methylcellulose has a molecular weight ≥20000.

[0021] Preferably, in step 7), the length of the sepiolite chopped fiber powder is 0.2-0.5 mm, the length of the zirconium-containing aluminum silicate chopped fiber powder is 0.2-0.5 mm, the solid content of the silica sol is ≥35%, the molecular weight of the polyacrylic acid is ≥50000 and the solid content is ≥40%, the molecular weight of the sodium carboxymethyl cellulose is ≥500, the content of ammonium metavanadate is ≥95%, and the content of manganese tetroxide is ≥95%.

[0022] Preferably, the extrusion pressure of the production material when it is extruded through an extruder to form a support blank, flange ring, and tail sealing cover is 5-8 MPa.

[0023] The high-strength, large-size fiber filter tube obtained by the aforementioned method is described.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1) This invention optimizes and recombines the formula multiple times and adopts the traditional extrusion method, while maintaining the product's binder coating method and low-temperature sintering technology to ensure high bending strength of the product, thereby solving the problem of pulse jet breakage caused by insufficient strength that is common in the current market.

[0026] 2) This invention employs an extrusion molding composite rapid heating and shaping followed by cooling to prevent cracking, which can form outer diameters... Large-sized filter cartridges with a length exceeding 3 meters solve the technical problem of easy deformation of large extruded components.

[0027] 3) This invention uses a specific formulation system, preferably ammonium metavanadate as the catalyst support, and through a low-temperature sintering temperature of the membrane layer, the ammonium metavanadate added to the retention membrane undergoes a calcination reaction to generate vanadium pentoxide catalyst, which is then used together with manganese tetroxide to obtain a high-strength fiber filter tube with catalytic function.

[0028] 4) The present invention adopts an inclined support and a loading method with a circular alumina sleeve lining the clay blank. The inclined loading method makes full use of the force component characteristics in mechanics, effectively dispersing the shrinkage resistance of the large component blank during firing, and avoiding cracking caused by large shrinkage resistance. The loading method with a circular alumina sleeve lining effectively supports the product to prevent collapse and deformation during the high-temperature softening process, ensuring the roundness of the large component. Attached Figure Description

[0029] Figure 1 It is a structural diagram of a support body containing an adhesive flange and a tail sealing hole;

[0030] Figure 2 This is a schematic diagram of the special inclined support structure in Example 1;

[0031] Figure 3This is a schematic diagram of the alumina-lined fiber tube in Example 1. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is further described below with reference to specific embodiments. Unless otherwise specified, the technical means used in the following embodiments are all conventional means well known to those skilled in the art. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0033] In the following examples, the purple clay used was selected from purified Jinzhou, Liaoning; the black mud used was selected from purified Shiwan, Foshan; the white mud used was purified; the borax used contained 40% B2O3; the added water was clean tap water; the length of the short-cut alumina fibers used was 2-5 mm; the solid content of the water glass used was 35% and the modulus was 2.6; the solid content of the silica sol used was 40%; the molecular weight of the sodium hydroxypropyl methylcellulose used was 50,000; the length of the sepiolite short-cut fiber powder used was 0.2-0.5 mm; the length of the zirconium-containing aluminum silicate short-cut fiber powder used was 0.2-0.5 mm; the molecular weight of the polyacrylic acid used was 100,000 and the solid content was 42%; the molecular weight of the sodium carboxymethyl cellulose used was 1,000; the ammonium metavanadate used was analytical grade; and the manganese tetroxide used had a content of 97%.

[0034] Example 1

[0035] A method for preparing a high-strength, large-size fiber filter tube, the specific steps of which are as follows:

[0036] 1. Prepare production material B

[0037] (1) Preparation of pre-made small material A: 29.52 parts of purple wood knot soil, 21.99 parts of Guangdong black mud, 13.65 parts of Wuxi white mud, 6.27 parts of borax and 28.57 parts of water were added to a planetary ball mill. After ball milling for 20 hours, the fineness D50 of the slurry was measured to be 37 μm and the moisture content was 28%. After spray drying, granulation balls with a moisture content of 3.2% were obtained, and pre-made small material A was obtained.

[0038] (2) Add 10 parts of pre-made small material A, 65 parts of chopped alumina fiber, 11 parts of water glass, 12 parts of silica sol, 2 parts of sodium hydroxypropyl methylcellulose, and 40 parts of added water to a high-speed Elysee mixer and mix at high speed for 25 minutes. The moisture content is 27%. The mixed mud is then subjected to non-vacuum mud-making in a mud-making machine to form blocks. The mud temperature is controlled to be ≤40℃ to obtain production material B.

[0039] 2. Forming of the support body blank, flange ring, and tail sealing cover plate.

[0040] (1) Pre-fabrication of flange ring and tail sealing cover: The production material B prepared above is extruded on an extruder with an outer diameter of... Inner diameter is A 40mm long ring is cut into a ring-shaped flange; the extrusion diameter is... A solid clay section with a length of 30mm is cut into a tail sealing cover plate. The extruded flange ring and tail sealing cover plate are dried at 110℃ until the moisture content is ≤2% to obtain a dry blank of flange ring and dry blank of tail sealing cover plate.

[0041] (2) Forming of the support blank through the tube: The production material B prepared above is extruded into a support blank tube on an extruder. The extrusion speed is maintained at 1-1.2 m / min, the extrusion pressure is 5.6-7.2 MPa, and the extrusion length is 3.4 m. After the blank is extruded through the outlet, it enters an infrared drying box (heating anti-deformation zone) with a length of 2000 mm, which is set 10 cm away from the outlet. The infrared drying box is set to dry the outer surface of the blank tube at 85°C. At the same time, the residual heat of the tunnel kiln at 85°C and the warm air with a humidity of ≤5% are used to heat the inner surface of the support blank tube through the rotating air guide pipe set in the internal cavity. When the blank tube leaves the heating anti-deformation zone, it quickly enters the cold air zone with a length of 2000 mm at 20-25°C for rapid cooling (cold air anti-cracking zone). After the support blank tube leaves the heating anti-deformation zone, the internal heat conduction pipe is removed. The formed support blank tube continues to move forward until it exits the cold air anti-cracking zone and the composite drying and shaping is completed.

[0042] (3) 18 products were extruded, of which 2 were scrapped due to surface cracking, and the remaining 16 were put into the next process.

[0043] 3. Microwave drying of the support body clay tube

[0044] (1) Sixteen shaped support body clay tubes were subjected to continuous microwave drying at 110℃ for a length of 14.8m, resulting in support body dry tubes with a dry moisture content of ≤3%, all of which were qualified.

[0045] 4. Flange bonding

[0046] (1) The support blank pipe is vertically inserted into the flange blank and fixed on the work station of the dispensing machine. Refractory low temperature mortar is injected into the gap between the inner ring of the flange and the outer ring of the pipe. The mortar is scraped flat and left to stand for 1 hour. The excess mortar on the flat surface is repaired. When the mortar is partially cured and can resist deformation, it is dried in a 120℃ hot air drying room for 60 minutes to obtain the support blank pipe with the bonded flange.

[0047] 5. Firing of the fiber tube support clay blank

[0048] (1) The dry blank of the support body containing the adhesive flange is placed on a special inclined support device for firing. The temperature is raised from room temperature to 300℃ for 2 hours at a heating rate of 120℃ / h, and then raised from 300℃ to 850℃ for 2 hours at a heating rate of 60℃ / h to form the fiber tube support body base pipe containing the adhesive flange.

[0049] (2) After the 16 products were fired, one of them was scrapped due to breakage, and the remaining 15 were qualified fiber tube support matrix pipes with adhesive flanges.

[0050] Specialized tilting support equipment such as Figure 2 and Figure 3 As shown, the inclined support device consists of an alumina liner 1, an inclined support base 2, a baffle 3, and a support plate 4. The support plate 4 is semi-arc-shaped (or V-shaped), and both the support plate 4 and the baffle 3 are mounted on the inclined support base 2. The support plate 4 is installed at both ends of the inclined support base 2, and the baffle 3 is installed at the lower end (non-inclined end) of the alumina liner 1. During operation, the alumina liner 1, passing through the fiber tube support matrix of the adhesive flange, is first erected on the support plates 4 at both ends, with the alumina liner 1 inclined at 30-45°. The baffle 3 and the support plate 4 prevent the support from falling.

[0051] 6. Adhesion of the tail end sealing cover plate

[0052] (1) The fiber tube support base pipe with the adhesive flange is placed vertically with the flanged end facing down and fixed on the dispensing machine. Refractory low-temperature adhesive is injected into the gap between the end cap and the end of the pipe, covering the other end. After standing for 1 hour, additional adhesive is applied to repair any excess adhesive. Once the adhesive has partially cured and is resistant to deformation, it is dried in a 120℃ hot air drying oven for 60 minutes to obtain a support base pipe with an adhesive flange sealed at one end. Figure 1 As shown.

[0053] Example 2

[0054] 1. Prepare production material B

[0055] (1) Pre-made small material A was prepared using Example 1;

[0056] (2) Add 15 parts of pre-made small material A, 70 parts of short-cut alumina fiber, 6 parts of water glass, 7 parts of silica sol, 2 parts of sodium hydroxypropyl methylcellulose, and 40 parts of added water to a high-speed Elysee mixer and mix at high speed for 25 minutes. The moisture content is 29%. The mixed material is then subjected to non-vacuum plucking in a plucking machine to form blocks. The temperature of the plucking material is controlled to be ≤40℃ to obtain production material B.

[0057] 2. Forming of the support body blank, flange ring, and tail sealing cover plate.

[0058] (1) The flange ring and the tail sealing cover plate were prepared using the blanks of the flange ring and the tail sealing cover plate prepared in Example 1.

[0059] (2) Preparation of the support blank: The production material B prepared above is extruded into a support blank tube on an extruder. The extrusion speed is maintained at 1-1.2 m / min, the extrusion pressure is 5.1-6.6 MPa, and the extrusion length is 3.4 m. After the blank is extruded through the outlet, it enters an infrared drying box (heating anti-deformation zone) with a length of 2000 mm, which is set 10 cm away from the outlet. The infrared drying box is set to dry the outer surface of the blank tube at 85°C. At the same time, the residual heat of the tunnel kiln at 85°C and the warm air with a humidity of ≤5% are used to heat the inner surface of the support blank tube through the rotating air guide pipe set in the internal cavity. When the blank tube leaves the heating anti-deformation zone, it quickly enters a cold air zone with a length of 2000 mm and a temperature of 20-25°C for rapid cooling (cold air anti-cracking zone). After the support blank tube leaves the heating anti-deformation zone, the internal heat conduction pipe is removed, and the formed support blank tube continues to move forward until it exits the cold air anti-cracking zone and the composite drying and shaping is completed.

[0060] (3) 20 products are extruded, one of which is scrapped due to surface cracking, and the remaining 19 are sent to the next process.

[0061] 3. Microwave drying of the support body clay tube

[0062] (1) 19 shaped support body clay tubes were put into a continuous microwave oven with a length of 14.8m and forced to dry at 110℃ to obtain support body dry tubes with a dry moisture content of ≤3%, all of which were qualified.

[0063] 4. The flange bonding and the firing of the fiber tube support clay blank were both prepared using the same process as in Example 1;

[0064] (1) After firing 19 products, one of them was scrapped due to breakage, one was scrapped due to severe deformation (diameter deviation ≥ 4mm (long and short diameters)), and the remaining 17 were qualified fiber tube support matrix pipes with adhesive flanges.

[0065] 5. The tail end sealing cover plate is bonded using the same process as in Example 1 to obtain a support base pipe with a sealing flange at one end.

[0066] Comparative Example 1

[0067] 1. Prepare production material B according to the composition of Example 1, and prepare production material B and flange ring and tail sealing cover plate prefabrication using the same process as in Example 1;

[0068] 2. Preparation of the support blank

[0069] (1) Extruding the support blank on the extruder, maintaining an extrusion speed of 1 to 1.2 m / min and an extrusion pressure of 5.1 to 6.3 MPa, after the blank is extruded through the outlet, it is supported by a conventional non-powered roller. When the forming length reaches 3.4 meters, the machine is stopped and cut off, and then microwave drying is performed.

[0070] (2) 25 products were extruded, of which 19 were scrapped due to severe deformation (diameter deviation ≥ 4 mm (long and short diameters)), and the remaining 6 were sent to the next process.

[0071] 3. Six blanks were subjected to continuous microwave drying at 110℃ for a length of 14.8m, resulting in dry blanks with a moisture content of ≤3%, all of which passed the test.

[0072] 4. Perform flange bonding according to the process in Example 1;

[0073] 5. Firing of the support clay body:

[0074] (1) Six support blanks with adhesive flanges were placed on a special inclined support support device for firing. The temperature was raised from room temperature to 300℃ for 2 hours at a heating rate of 120℃ / h, and then raised from 300℃ to 850℃ for 2 hours at a heating rate of 60℃ / h to form the fiber tube support base tube.

[0075] (2) After the 6 products were fired, one of them was scrapped due to breakage, and the remaining 5 were qualified support base tubes.

[0076] 6. The support base tube is obtained by bonding the tail sealing cover plate according to the same process as in Example 1.

[0077] Comparative Example 2

[0078] 1. Prepare production material B according to the composition of Example 2, and prepare production material B and flange ring and tail sealing cover plate prefabrication using the same process as in Example 2;

[0079] 2. Preparation of the support blank

[0080] (1) The support blank is extruded on an extruder at a speed of 1-1.2 m / min and a pressure of 5.2-6.9 MPa. The length is 3.4 m. After the blank is extruded through the outlet, it enters an infrared drying box (heating and anti-deformation zone) 2000 mm long, located 10 cm from the outlet. The infrared drying box is set to dry the outer surface of the blank tube at 85°C. At the same time, the residual heat of the tunnel kiln at 85°C and the warm air with a humidity of ≤5% are used to heat the inner surface of the support blank tube through a rotating air guide pipe in the internal cavity. When the blank tube leaves the heating and anti-deformation zone, it quickly enters a cold air zone of 20-25°C and 2000 mm long for rapid cooling (cold air anti-cracking zone). After the support blank tube leaves the heating and anti-deformation zone, the internal heat pipe is removed. The formed support blank tube continues to move forward until it exits the cold air anti-cracking zone and the composite drying and shaping is completed.

[0081] (2) 25 products were extruded, of which 2 were scrapped due to surface cracking, and the remaining 23 were sent to the next process.

[0082] 3. The support blank was microwave dried according to the process in Example 1, and all of them passed the test.

[0083] 4. Perform flange bonding according to the process in Example 1;

[0084] 5. Firing of the support body clay blank:

[0085] (1) The support body containing the adhesive flange is loaded into the kiln and fired in a conventional non-inclined sleeve support manner. The temperature is raised from room temperature to 300℃ for 2 hours at a heating rate of 120℃ / h, and then raised from 300℃ to 850℃ for 2 hours at a heating rate of 60℃ / h to form the fiber tube support body base tube.

[0086] (2) After the 23 products were fired, 19 of them were scrapped due to severe deformation (diameter deviation ≥ 4mm (long and short diameters)), and the remaining 4 were put into the next process.

[0087] 6. The support base tube is obtained by bonding the tail sealing cover plate according to the process of Example 1.

[0088] Example 3

[0089] (1) Prepare retention suspension slurries according to the components of Products 1-2 and Comparative Products 1-2 in Table 1: Add sepiolite chopped fiber powder and zirconium-containing aluminosilicate chopped fiber powder to a magnetic stirrer and stir and disperse for 15 min. Then add silica sol, sodium carboxymethyl cellulose, ammonium metavanadate and manganese tetroxide, and continue stirring and dispersing for 20 min. Finally add polyacrylic acid and continue stirring and dispersing for 10 min to prepare retention membrane suspension slurries. Comparative Product 1 uses the suspension slurry prepared by Product 1. The moisture content of both Product 1 and Comparative Product 1 is 40.3% and the viscosity at 20°C is 36 Pa·s. The moisture content of Product 2 is 39.6% and the viscosity at 20°C is 33 Pa·s. The moisture content of Comparative Product 2 is 41.1% and the viscosity at 20°C is 31 Pa·s. Products 1-2 and Comparative Products 1-2 are coated tubes with retention membrane slurries coated on the surface of a support base tube with an adhesive flange and one end sealed, prepared in Example 1.

[0090] Table 1. Composition and Requirements of Membrane Retention Slurry

[0091]

[0092] (2) The membrane suspension slurry prepared in step (1) was uniformly sprayed onto the surface of the fiber tube support prepared in Example 1 using a 1.2 mm diameter air gun at a pressure of 0.32 MPa. The spraying thickness of Product 1 was 200 μm; the spraying thickness of Product 2 was 300 μm; the control product 1 used the membrane suspension slurry prepared in Product 1 with a spraying thickness of 100 μm; the control product 2 had a spraying thickness of 300 μm.

[0093] (3) The high-strength large-size fiber tube support film tube is heated from room temperature to 120℃ for 1 hour at a heating rate of 60℃ / h, and then heated from 120℃ to 400℃ for 2 hours at a heating rate of 60℃ / h to obtain a high-strength large-size fiber filter tube.

[0094] Example 4

[0095] The performance of the support matrix tubes prepared in Examples 1-2 and Comparative Examples 1-2 was tested, and the results are shown in Table 2. The performance of Products 1-2 and Comparative Products 1-2 prepared in Example 3 was tested, and the results are shown in Table 3. In this invention, vernier calipers and rulers were used to inspect the dimensional accuracy of the clay blanks, and the appearance was visually inspected. Flexural strength was tested according to GB / T3001-2017; porosity was tested according to GB / T2997-2015; and thermal shock resistance was tested according to GB / T3298-2022. The pressure difference test method was as follows: clean air was used in a SuperFlow back pressure meter at a flow rate of 1.0 m / min. xThe conversion efficiency test method is as follows: A mixed gas with a flow rate of 100 ml / min and a NOx concentration of 300 ppm is passed through the outer surface of the sample. The mixed gas that has passed through the outer surface of the sample is collected on the inner side of the sample and then connected to the NOx collection point. x Conversion efficiency tester, by detecting NO x The NO was determined by the ratio of flow rates before and after the sample. x Conversion efficiency.

[0096] Table 2 Performance Results of Support Matrix Tube Products

[0097]

[0098] Table 3 Product Performance Results

[0099]

[0100]

[0101] As shown in Table 2, in the process of preparing the support body clay blank, the product using composite drying can be quickly shaped, ensuring the roundness of the molded part and preventing cracking. Its clay blank quality rate is significantly higher than that of the product without composite drying. In the firing process, the inclined, alumina-lined sleeve support method is used, and the firing quality rate of the fiber tube support is significantly higher than that of the product using conventional methods. The fiber tube support prepared by the preferred formula of this invention has a strength ≥10MPa, a porosity ≥72%, and thermal shock resistance ΔT700℃ without cracking after three cycles.

[0102] As shown in Table 3, the membrane-forming formula of this invention, which includes ammonium metavanadate and manganese tetroxide and is combined with a low-temperature sintering process, produces a high-strength, large-size fiber filter tube with a net air pressure difference ≤200 Pa (1 m / min); NO x Catalytic conversion efficiency ≥92%.

[0103] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a high-strength, large-size fiber filter tube, characterized in that, Includes the following steps: 1) Prepare the pre-made small material: short-cut alumina fiber: water glass: silica sol: sodium hydroxypropyl methylcellulose in the ratio of (10~15): (65~70): (6~11): (7~12): (1~2), add a certain amount of water and mix at high speed for 15~45 minutes, and obtain the production material by non-vacuum mud removal; 2) The production material obtained in step 1) is extruded through an extruder to form flange rings and tail sealing cover plates, and cut into the required shapes. The materials are dried at 90~110℃ until the moisture content is ≤2% to obtain flange ring blanks and tail sealing cover plate blanks. 3) The production material obtained in step 1) is extruded through an extruder to form a support blank tube. The formed support blank tube first passes through a heating and anti-deformation zone at 80~95℃ for infrared drying of the outer surface of the blank tube. At the same time, the inner surface of the support blank tube is heated by hot air at 80~95℃ and humidity ≤5% through an internal cavity rotating air guide tube. Then, it quickly enters the cold air zone at 20~25℃ for rapid cooling. Finally, it undergoes continuous microwave drying at 95~120℃ to produce a dried support blank tube. 4) The flange blank obtained in step 2) is bonded to the front end of the support blank pipe using fire putty. After bonding, it is dried at 100~120℃ for 30~60min to obtain a support blank pipe containing the bonded flange. 5) Place the dry blank pipe with adhesive flange obtained in step 4) on an inclined support and fire it. Heat it from room temperature to 300℃ at a heating rate of ≤5℃ and hold it for 1~2 hours. Then heat it from 300℃ to 850℃ at a heating rate of ≤3℃ and hold it for 1~3 hours to form the fiber tube support matrix pipe with adhesive flange. 6) The dry blank of the tail sealing cover obtained in step 2) is bonded to the rear end of the fiber tube support matrix tube containing the bonding flange using fire putty. After bonding, it is dried at 100~120℃ for 30~60min to obtain a support matrix tube with a bonding flange at one end. 7) Prepare a membrane suspension slurry by mixing sepiolite chopped fiber powder, zirconium-containing aluminum silicate chopped fiber powder, silica sol, polyacrylic acid, sodium carboxymethyl cellulose, ammonium metavanadate, and manganese tetroxide in the ratio of (20~30): (35~45): (20~25): (5~8): (1.5~2.8): (3~5): (3~5), add a certain amount of water and stir for 25~45 minutes to prepare the membrane suspension slurry; use a pressure air gun to evenly spray the membrane suspension slurry onto the surface of the support base tube with an adhesive flange sealed at one end to obtain a fiber tube coated wet blank tube; 8) The fiber tube coated wet blank obtained in step 7) is air-dried at 80~100℃. After the water loss rate is ≥96%, the membrane layer is fired. The temperature is increased from room temperature to 120℃ at a heating rate of ≤5℃ and held for 1~2 hours. Then the temperature is increased from 120℃ to 400℃ at the same heating rate and held for 2~3 hours to obtain a high-strength large-size fiber filter tube.

2. The method for preparing a high-strength, large-size fiber filter tube according to claim 1, characterized in that, In step 1), the preparation process of the pre-made small material is as follows: the mixture is prepared according to the ratio of purple clay: Guangdong black mud: Wuxi white mud: borax: water = (20~40): (20~30): (13~15): (5~10): (20~30), and after ball milling for 15~20 hours, it is spray dried to obtain granulated balls with a moisture content of <5%, thus obtaining the pre-made small material.

3. The method for preparing a high-strength, large-size fiber filter tube according to claim 1, characterized in that, In step 3), the dimensions of the prepared support blank tube are: outer diameter Ø150~Ø200mm, inner diameter Ø100~Ø150, and length ≥3000mm.

4. The method for preparing a high-strength, large-size fiber filter tube according to claim 1, characterized in that, In step 1), the non-vacuum mud-making process is as follows: the mixed mud is processed into blocks by a mud-making machine in a non-vacuum manner, and the mud temperature is controlled to be ≤40℃ and the moisture content is 25~30%.

5. The method for preparing a high-strength, large-size fiber filter tube according to claim 1, characterized in that, In step 7), the diameter of the pressure air gun is ≥1mm, and the coating is sprayed on the surface of the support base tube with an adhesive flange that is sealed at one end under a pressure of 0.2~0.5MPa, with a coating thickness of 150~300μm.

6. The method for preparing a high-strength, large-size fiber filter tube according to claim 2, characterized in that, In step 1), the length of the chopped alumina fiber is 2~5mm, the borax contains B2O3 ≥35%, the water glass has a solid content ≥34.2% and a modulus of 2.2~3, the silica sol has a solid content ≥40%, and the sodium hydroxypropyl methylcellulose has a molecular weight ≥20000.

7. The method for preparing a high-strength, large-size fiber filter tube according to claim 1, characterized in that, In step 7), the length of the sepiolite chopped fiber powder is 0.2~0.5mm, the length of the zirconium-containing aluminum silicate chopped fiber powder is 0.2~0.5mm, the solid content of the silica sol is ≥35%, the molecular weight of the polyacrylic acid is ≥50000 and the solid content is ≥40%, the molecular weight of the sodium carboxymethyl cellulose is ≥500, the content of ammonium metavanadate is ≥95%, and the content of manganese tetroxide is ≥95%.

8. The method for preparing a high-strength, large-size fiber filter tube according to claim 1, characterized in that, The extrusion pressure of the production material when it is extruded through an extruder to form a support blank, flange ring, and tail sealing cover plate is 5~8MPa.

9. The high-strength large-size fiber filter tube obtained by the preparation method of the high-strength large-size fiber filter tube according to any one of claims 1-8.

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