High silica fiber-based catalyst carrier and preparation method thereof

Abstract

The invention provides a high silica fiber-based catalyst carrier and a preparation method thereof. The preparation method of the high-silica fiber-based catalyst carrier comprises the following steps: S1, mixing an enhancer, a binder, a dispersant, a defoaming agent, a pH regulator and deionized water, and uniformly stirring to prepare enhanced slurry; s2, performing coreless rolling on the high-silica fiber paper through corrugated rollers with different heights, and cutting the high-silica fiber paper into a precursor; and S3, dipping the precursor obtained in the S2 into the reinforced slurry obtained in the S1, and sequentially drying and roasting to obtain the catalyst. The high silica fiber-based catalyst carrier is prepared by the preparation method, and the carrier is suitable for SCR, DOC and ASC catalysts. The carrier can resist the high temperature of 1000 DEG C or above, can remarkably improve the high-temperature strength of the catalyst, reduce the density of the catalyst, reduce the energy consumption and lower the production cost, is wide in application range, can be applied to carriers of SCR, DOC and ASC catalysts in national VI catalysts, and has wide industrial application prospects.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of catalysts, and particularly relates to a high-silica fiber-based catalyst carrier and a preparation method thereof. BACKGROUND

[0002] At present, the corrugated SCR catalyst mainly meets the national standard V, and the strength of the existing glass fiber carrier cannot meet the hydrothermal aging requirement of the national standard VI above 700 DEG C, so a new fiber needs to be used to replace the glass fiber to improve the high-temperature strength of the catalyst. The high-silica fiber has a silica content of more than 95%, has high-temperature resistance, and can resist a temperature above 1000 DEG C. The high-silica fiber has similar properties to the glass fiber and is obtained by acid washing of the alkali-free glass fiber.

[0003] The high-silica fiber is prepared by acid washing to remove other elements in the alkali-free glass fiber, improve the silica content to the standard of the high-silica fiber, and improve the high-temperature resistance of the fiber. However, the acid washing causes a certain change in the internal structure of the high-silica fiber, the fiber strength is reduced to a certain extent, and the fiber is shrunk to a certain extent at high temperatures. The high-silica fiber is obviously cracked when the high-silica fiber is used to prepare the catalyst carrier of the national standard VI.

[0004] Therefore, the application is provided. SUMMARY

[0005] The application aims to provide a high-silica fiber-based catalyst carrier and a preparation method thereof to solve the above problems.

[0006] To achieve the above object, the application adopts the following technical scheme.

[0007] A preparation method of a high-silica fiber-based catalyst carrier, comprising the following steps:

[0008] S1: mixing a reinforcing agent, a binder, a dispersing agent, a defoaming agent, a pH regulator and deionized water, and stirring uniformly to prepare a reinforcing slurry; adjusting the pH value to 8-10 under alkaline conditions or 2-4 under acidic conditions according to the acid or alkaline of the selected additive, so that the additive can play the maximum effect.

[0009] The reinforcing agent comprises one or more of alumina, silica, cordierite powder and amorphous alumina.

[0010] Preferably, the particle size D50 of the reinforcing agent is 0.5-5 mu m. If the powder particle size is too small, the strength is weak and it is difficult to support. If the powder particle size is too large, it is difficult to disperse uniformly, the slurry stability is poor, the interaction with the binder is weak, the powder is easy to fall off after being embedded on the surface of the high-silica fiber, and the carrier strength cannot be effectively improved.

[0011] The binder comprises one or more of silica sol, aluminum sol, silica-aluminum sol, titanium sol, zirconium sol;

[0012] The dispersant comprises one or more of alkyl benzene sulfonate, fatty alcohol sulfate, polyethylene glycol, polyvinyl alcohol, polyol, alkyl alcohol amide, imidazoline, polyacrylic acid emulsion, organosilicon;

[0013] Preferably, the dispersant is used in an amount of 0.1-2% of the mass of the reinforcing agent;

[0014] The defoaming agent comprises one or more of resin, alcohol, alkyne, ether, organosilicon, mineral oil, polyether, polycarboxylate, polyacrylic acid;

[0015] Preferably, the defoaming agent is used in an amount of 0.1-5% of the mass of the reinforcing agent;

[0016] The pH regulator comprises one or more of ammonia, ethanolamine, nitric acid, citric acid, oxalic acid;

[0017] Preferably, the preparation of the reinforcing slurry further comprises: first stirring the reinforcing agent, the pH regulator and deionized water at a speed of 300-500 r / min for 3-5 h to obtain slurry one;

[0018] The binder, the dispersant, and the defoaming agent are added to the slurry one in a certain proportion and stirred at a speed of 50-100 r / min for 3-5 h to obtain a uniform reinforcing slurry;

[0019] The pH value of the slurry one is 8-10 or 2-4;

[0020] When the pH value of the slurry one is 8-10, the binder, the dispersant, and the defoaming agent are selected to be alkaline reagents; when the pH value of the slurry one is 2-4, the binder, the dispersant, and the defoaming agent are selected to be acidic reagents;

[0021] The certain proportion is a mass ratio of the reinforcing agent, the dispersant, and the defoaming agent of 100:0.1-2:0.1-5.

[0022] Preferably, the mass of the solid component of the binder is 10-30% of the mass of the reinforcing agent;

[0023] In a preferred embodiment of the present application, the reinforced slurry is prepared in two steps. The first step is mainly to treat the reinforcing agent in a solution at a specific pH value, so that hydrolysis or acidolysis can occur, forming a slurry form that is easier to disperse. The second step is to add the additives, mainly to uniformly disperse the binder and the reinforcing agent together through the action of dispersants and defoamers. When impregnated on the high-silica fiber carrier, a film with certain strength is formed on the surface of the fiber filaments, which improves the strength of the carrier as a whole.

[0024] Therefore, the stirring rates of the above two steps cannot be the same. In the first step, there is a certain chemical reaction of hydrolysis or acidolysis. Under the conditions of the preferred pH value and the particle size of the reinforcing agent in the present application, a stirring rate as high as 300-500 r / min is required to promote the reaction to be efficient and complete. However, after adding the additives in a specific ratio in the second step, the stirring rate cannot be as high as this, otherwise it is easy to cause side reactions or generate a large amount of foam or suspended particles or even blocky agglomerates, which are many factors that are not conducive to the uniform dispersion and stability of the system, and thus affect the high-temperature resistance performance. Therefore, the stirring rate in the second step needs to be reduced to 50-100 r / min, which ensures that the above problems can be overcome and the active ingredients in the system can be fully dispersed without increasing the amount of additives.

[0025] S2: The high-silica fiber paper is wound without a core through corrugated rollers of different heights, and cut into precursors;

[0026] The height of the corrugated roller is 1.0-3.5 mm;

[0027] S3: The precursor obtained in S2 is impregnated in the reinforced slurry obtained in S1 for 15-30 min, and then dried and calcined in sequence to obtain the product.

[0028] The drying includes any one of vacuum drying, hot air drying, natural air drying, and microwave drying;

[0029] The calcination temperature is 450-600℃, and the time is 2-6 h.

[0030] Preferably, S3 is: the precursor obtained in S2 is first impregnated in the reinforced slurry one obtained in S1, and then impregnated in the reinforced slurry two obtained in S1, and then dried and calcined in sequence to obtain the product.

[0031] The reinforcing agent used to prepare the reinforced slurry one is silicon oxide, and the reinforcing agent used to prepare the reinforced slurry two is amorphous alumina.

[0032] The silicon oxide powder skeleton material can improve the strength of the carrier, and the amorphous alumina powder skeleton material can reduce the shrinkage of the high-silica fiber carrier and reduce the cracking of the carrier. The two-layer coating can achieve the effects of filling the carrier skeleton, reducing the cracking of the carrier, and improving the strength of the carrier.

[0033] The application also provides a high-silica fiber-based catalyst carrier prepared by the preparation method, which is suitable for SCR, DOC and ASC catalysts.

[0034] The application provides a preparation method of a high-silica fiber-based catalyst carrier, which improves the holes of the high-silica fiber caused by pickling, adds aggregates to improve the strength, prevents high-temperature shrinkage, and selects the adhesion of a suitable binder, so that the prepared carrier has excellent high-temperature resistance and can withstand 1000 DEG C and above.

[0035] The application has the following beneficial effects:

[0036] The preparation method of the carrier provided by the application has low-cost raw materials, simple and controllable process, and is helpful to improve the high-temperature strength of the catalyst carrier, reduce the catalyst density, reduce the energy consumption, and reduce the production cost.

[0037] The high-silica fiber-based catalyst carrier provided by the application has a three-dimensional pore structure, so that the contact area of the catalyst is larger, the surface utilization rate of the catalyst can be improved, the use amount of the catalyst is reduced, and the production cost of the catalyst is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the specific embodiments of the application or the technical solutions in the prior art, the drawings needed in the description of the specific embodiments or the prior art will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0039] Figure 1 It is the appearance diagram of the product of Example 1;

[0040] Figure 2 It is the appearance diagram of the precursor of Comparative Example 1;

[0041] Figure 3 It is the appearance diagram of the cracking of the product of Comparative Example 3. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the embodiments of the application more clear, the technical scheme in the embodiments of the application will be described clearly and completely in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are only some of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application.

[0043] Example 1

[0044] The high-silica fiber-based catalyst carrier prepared by the preparation method provided in the application specifically comprises the following steps:

[0045] S1: preparation of reinforced slurry

[0046] Take 20 kg of amorphous alumina powder with a particle size of 1 μm, add 0.2 kg of citric acid and 69 kg of deionized water, and stir at a stirring rate of 450 r / min for 5 h to obtain a slurry one with a pH value of 3; then add 12 kg of aluminum sol to the obtained slurry one, and then add 45 g of imidazoline and 105 g of acetylene defoaming agent, and stir uniformly at 70 r / min to obtain a reinforced slurry;

[0047] S2: making the precursor into a by passing the high-silica fiber paper through a 2.0 mm corrugated roller, and winding and cutting without a core;

[0048] S3: immersing the precursor in the reinforced slurry of S1, drying by hot air for 3 h, and calcining at 580 ℃ for 3 h to obtain the high-silica fiber-based catalyst carrier.

[0049] It is tested that the bulk density of the obtained high-silica fiber-based catalyst carrier is 115 g / L, the coating strength is relatively high, there is no powder falling, the interlayer adhesion of the carrier is strong, and there is basically no cracking. The appearance diagram is shown in Figure 1 , and Figure 1 , and it can be clearly seen that there is no cracking.

[0050] Example 2

[0051] The high-silica fiber-based catalyst carrier prepared by the preparation method provided in the application specifically comprises the following steps:

[0052] S1: preparation of reinforced slurry one

[0053] Take 10 kg of silica powder, add 0.2 kg of ammonia water and 80 kg of deionized water, and stir at a stirring rate of 500 r / min for 3 h to obtain a slurry one with a pH value of 9; then add 10 kg of basic silica sol to the obtained slurry one, and add 40 g of silicone dispersant and 70 g of polyether defoaming agent, and stir uniformly at 50 r / min to obtain a reinforced slurry one;

[0054] S2: preparation of reinforced slurry two

[0055] Take 10 kg of amorphous alumina powder, add 0.2 kg of citric acid and 70 kg of deionized water, and stir at a stirring rate of 500 r / min for 5 h to obtain a slurry one with a pH value of 4; then add 13 kg of aluminum sol to the obtained slurry one, and add 50 g of sodium dodecyl benzene sulfonate and 100 g of polyacrylic acid defoaming agent, and stir uniformly at 50 r / min to obtain a reinforced slurry two;

[0056] S3, the high-silica fiber paper is passed through a 2.7mm corrugated roller to make a precursor of by coreless winding and cutting;

[0057] S4: the precursor in S2 is immersed in the reinforced slurry solution one in S1, dried by microwave for 3h, then immersed in the reinforced slurry solution two, dried by microwave for 3h, and calcined at 500℃ for 6h to obtain a high-silica fiber-based catalyst carrier.

[0058] Test results show that the bulk density of the obtained high-silica fiber-based catalyst carrier is 126g / L, the coating strength is strong, there is no powder falling, and the carrier has no cracking.

[0059] Comparative Example 1

[0060] A high-silica fiber-based catalyst carrier is prepared, specifically including the following steps:

[0061] S1: preparation of a reinforced slurry solution

[0062] 20kg of alumina powder is weighed, 0.2kg of nitric acid and 60kg of deionized water are added and stirred, the stirring speed is 50r / min, and the stirring time is 4h to obtain a slurry solution one; 10kg of acid silica sol is added to the obtained slurry solution one, then 60g of polyacrylic acid emulsion and 120g of silicone defoaming agent are added and stirred uniformly to obtain a reinforced slurry solution;

[0063] S2, the high-silica fiber paper is passed through a 2.2mm corrugated roller to make a precursor of by coreless winding and cutting; as Figure 2 shown;

[0064] S3: the precursor in S2 is immersed in the reinforced slurry solution in S1, dried by microwave for 2h, and calcined at 500℃ for 4h to obtain a high-silica fiber-based catalyst carrier.

[0065] Test results show that the bulk density of the obtained high-silica fiber-based catalyst carrier is 118g / L, the coating strength is general, there is powder falling, and the carrier has shrinkage cracking between layers.

[0066] During the acidification process of the alumina powder, the viscosity gradually rises to form an aluminum gel, and after mixing with the binder silica sol, the uniformity of the slurry solution is slightly poor. During the drying and calcining process, the thermal expansion coefficients of the aluminum gel and the silica gel are inconsistent, which leads to falling off, cracking and shrinkage.

[0067] Comparative Example 2

[0068] A high-silica fiber-based catalyst carrier is prepared, specifically including the following steps:

[0069] S1: preparation of a reinforced slurry solution

[0070] Take 20 kg of silica powder, add 1.0 kg of ethanolamine and 60 kg of deionized water to stir, stirring at 80 r / min, stirring time 2h, get slurry one; to the obtained slurry one, add 12 kg of alkaline silica sol, then add 50 g of polyvinyl alcohol and 100 g of mineral oil defoaming agent, stir evenly to get reinforced slurry;

[0071] S2, the high-silica fiber paper passes through a 1.7 mm corrugated roller to make a precursor of by coreless winding and cutting;

[0072] S3: The precursor in S2 is immersed in the reinforced slurry of S1, vacuum dried for 3h, and calcined at 550℃ for 3h to obtain a high-silica fiber-based catalyst carrier.

[0073] Test results show that the bulk density of the obtained high-silica fiber-based catalyst carrier is 123 g / L, the coating strength is strong, there is no powder falling, and the interlayer shrinkage and cracking of the carrier are obvious.

[0074] Comparative Example 3

[0075] A high-silica fiber-based catalyst carrier is prepared, specifically including the following steps:

[0076] S1: Reinforced slurry preparation

[0077] Take 20 kg of cordierite powder, add 0.3 kg of ammonia water and 66 kg of deionized water to stir, stirring at 100 r / min, stirring time 6h, get slurry one; to the obtained slurry one, add 12 kg of alkaline silica sol, then add 45 g of polyacrylonitrile dispersant and 95 g of ether defoaming agent, stir evenly to get reinforced slurry;

[0078] S2, the high-silica fiber paper passes through a 1.5 mm corrugated roller to make a precursor of by coreless winding and cutting;

[0079] S3: The precursor in S2 is immersed in the reinforced slurry of S1, hot air dried for 3h, and calcined at 520℃ for 3h to obtain a high-silica fiber-based catalyst carrier.

[0080] Test results show that the bulk density of the obtained high-silica fiber-based catalyst carrier is 121 g / L, the coating strength is poor, the powder falling is serious, the interlayer adhesion of the carrier is poor, and the delamination is serious. The cracking degree is as shown in Figure 3 , and it can be seen from Figure 3 that the cracking is obvious.

[0081] Comparative Example 4

[0082] A high-silica fiber-based catalyst carrier is prepared, specifically including the following steps:

[0083] S1: Reinforced slurry preparation

[0084] Take 10 kg of alumina powder + 10 kg of silica powder, add 0.6 kg of ethanolamine and 75 kg of deionized water, stir at a stirring rate of 50 r / min for 3 h, to obtain a slurry one; add 15 kg of aluminum sol to the obtained slurry one, add 80 g of sodium dodecyl benzene sulfonate and 120 g of polyacrylic acid defoaming agent, and stir uniformly to obtain a reinforced slurry;

[0085] S2, pass the high-silica fiber paper through a 2.7 mm corrugated roller through coreless winding and cutting to make a precursor of ;

[0086] S3: immerse the precursor in S2 in the reinforced slurry of S1, and dry naturally for 30 h, and then calcine at 480℃ for 6 h to obtain a high-silica fiber-based catalyst carrier.

[0087] After testing, the bulk density of the obtained high-silica fiber-based catalyst carrier is 121 g / L, the coating strength is general, some powder is dropped, and the carrier has fine cracking.

[0088] Comparative Example 1

[0089] A high-silica fiber-based catalyst carrier is prepared, specifically including the following steps:

[0090] S1: preparation of reinforced slurry

[0091] Take 12 kg of aluminum sol, 45 g of dodecyl benzene sulfonate, and 120 g of polyacrylic acid defoaming agent, and stir uniformly to obtain a reinforced slurry;

[0092] S2, pass the high-silica fiber paper through a 1.5 mm corrugated roller through coreless winding and cutting to make a precursor of ;

[0093] S3: immerse the precursor in S2 in the reinforced slurry of S1, and dry with hot air for 3 h, and then calcine at 550℃ for 4 h to obtain a high-silica fiber-based catalyst carrier.

[0094] After testing, the bulk density of the obtained high-silica fiber-based catalyst carrier is 120 g / L, the coating strength is general, some powder is dropped, the interlayer adhesion of the carrier is weak, and a small amount of cracking occurs.

[0095] Comparative Example 2

[0096] A high-silica fiber-based catalyst carrier is prepared, specifically including the following steps:

[0097] S1: preparation of reinforced slurry

[0098] Take 10 kg of amorphous alumina powder, add 0.4 kg of citric acid and 68 kg of deionized water to stir, stir at 90 r / min, stir for 2.5 h, get slurry one; add 50 g of glycerol ester and 120 g of silicone defoaming agent to the obtained slurry one, stir uniformly to get reinforced slurry;

[0099] S2, the high-silicon fiber paper passes through a 1.8 mm corrugated roller to be wound and cut into a precursor of ;

[0100] S3: The precursor in S2 is immersed in the reinforced slurry of S1, vacuum dried for 6 h, and calcined at 520℃ for 5 h to obtain a high-silicon fiber-based catalyst carrier.

[0101] After testing, the bulk density of the obtained high-silicon fiber-based catalyst carrier is 122 g / L, the coating strength is poor, the powder falling is serious, and the interlayer adhesion of the carrier is general, and there is cracking.

[0102] Comparative Example 3

[0103] The difference from Example 1 is that the stirring rate in S1 step is 450 r / min.

[0104] Comparative Example 4

[0105] The difference from Example 1 is that the stirring rate in S1 step is 70 r / min.

[0106] Comparative Example 5

[0107] The difference from Example 1 is that the stirring rate in S1 step is 70 r / min and 450 r / min respectively.

[0108] Comparative Example 6

[0109] The difference from Example 2 is that the stirring rate in S1 and S2 steps is 500 r / min.

[0110] Comparative Example 7

[0111] The difference from Example 2 is that the stirring rate in S1 and S2 steps is 50 r / min.

[0112] The products prepared in Examples, Comparative Examples and Comparative Examples are subjected to compressive strength test, and the cutting sample is The test speed is 10 mm / min, and the test performance results are shown in Table 1:

[0113] Table 1 Performance test results of Examples and Comparative Examples

[0114] Item Coating strength Cracking condition Compressive strength / MPa Example 1 High No cracking 0.73 Example 2 High No cracking 1.34 Comparative Example 1 General With cracking 0.46 Comparative Example 2 High With obvious cracking 0.95 Comparative Example 3 Poor With severe cracking 0.21 Comparative Example 4 General With slight cracking 0.78 Comparative Example 1 General With slight cracking 0.32 Comparative Example 2 Poor With cracking 0.78 Comparative Example 3 General No cracking 0.71 Comparative Example 4 General With slight cracking 0.75 Comparative Example 5 General With slight cracking 0.58 Comparative Example 6 General With slight cracking 0.75 Comparative Example 7 General With slight cracking 0.75

[0115] The experimental results show that the silica powder skeleton material can improve the strength of the carrier, the amorphous alumina powder skeleton material can reduce the shrinkage of the high-silica fiber carrier, reduce the carrier cracking, and the two layered coating can achieve the effect of filling the carrier skeleton, reducing the carrier cracking and improving the carrier strength.

[0116] The catalyst carrier prepared in the embodiment of the application has lower density, which is reduced by about 40% compared with the density of the conventional cordierite carrier of the national VI catalyst in the art.

[0117] Please note that the technical features of the above embodiments can be combined in any way, and in order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the description. The above embodiments only express several implementation manners of the application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for those skilled in the art, without departing from the concept of the application, some modifications and improvements can be made, which are all within the protection scope of the application. Therefore, the protection scope of the patent of the application should be subject to the appended claims.

Claims

1. A method for preparing a high-silica fiber-based catalyst support, characterized in that, Includes the following steps: S1: Mix the reinforcing agent, binder, dispersant, defoamer, pH adjuster, and deionized water, and stir evenly to obtain the reinforced slurry; S2: The high-silica fiber paper is wound without core through corrugated rollers of different heights and cut into precursors; S3: The precursor obtained in S2 is immersed in the strengthening slurry obtained in S1, and then dried and calcined in sequence to obtain the product.

2. The preparation method according to claim 1, characterized in that, The reinforcing agent includes one or more of alumina, silicon dioxide, cordierite powder, and amorphous alumina; Preferably, the particle size D50 of the reinforcing agent is 0.5-5 μm.

3. The preparation method according to claim 1, characterized in that, The binder includes one or more of silica sol, aluminum sol, silica-alumina sol, titanium sol, and zirconium sol.

4. The preparation method according to claim 1, characterized in that, The dispersant includes one or more of the following: alkylbenzene sulfonates, fatty alcohol sulfates, polyethylene glycols, polyvinyl alcohols, polyols, alkylolamides, imidazoline compounds, polyacrylic acid emulsions, and organosilicon compounds; Preferably, the amount of the dispersant is 0.1-2% of the mass of the reinforcing agent.

5. The preparation method according to claim 1, characterized in that, The defoamer includes one or more of the following: resins, alcohols, alkynes, ethers, mineral oils, polyethers, and polycarboxylates. Preferably, the amount of the defoamer is 0.1-5% of the mass of the reinforcing agent.

6. The preparation method according to claim 1, characterized in that, The pH adjuster includes one or more of ammonia, ethanolamine, nitric acid, citric acid, and oxalic acid.

7. The preparation method according to claim 1, characterized in that, The height of the corrugated roller is 1.0-3.5mm.

8. The preparation method according to claim 1, characterized in that, The immersion time is 15-30 minutes; The drying process includes any one of vacuum drying, hot air drying, natural air drying, and microwave drying. The roasting temperature is 450-600℃ and the time is 2-6 hours.

9. The preparation method according to any one of claims 1-8, characterized in that, The preparation of the enhanced slurry further includes: first stirring the enhancer, pH adjuster and deionized water at a rate of 300-500 r / min for 3-5 h to obtain slurry one; Add the binder, dispersant, and defoamer to slurry one in a certain proportion, and stir at a speed of 50-100 r / min for 3-5 h to obtain a uniform reinforced slurry. The pH value of the first slurry is 8-10 or 2-4; When the pH value of the first slurry is 8-10, the binder, dispersant, and defoamer are alkaline reagents; when the pH value of the first slurry is 2-4, the binder, dispersant, and defoamer are acidic reagents. The specified ratio refers to the mass ratio of the reinforcing agent, dispersant, and defoamer being 100:0.1-2:0.1-5.

10. A high-silica fiber-based catalyst support prepared by the preparation method according to any one of claims 1-9, characterized in that, The support is suitable for SCR, DOC, and ASC catalysts.

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