Catalyst carrier and its preparation method and application

Abstract

The present invention discloses a catalyst carrier and its preparation method and application, belonging to the technical field of catalyst carriers. The preparation method comprises the following steps: aluminum sol is mixed with a composite template, tin chloride and silica sol to obtain a slurry; the slurry is made into a carrier wet ball, which is dried and calcined to obtain the catalyst carrier; the composite template comprises a surfactant and an organic amine, the surfactant is a zwitterionic surfactant and a nonionic surfactant, and the organic amine is hexamethylenetetramine; the mass ratio of the surfactant to the organic amine is 1:10-20; the mass ratio of the zwitterionic surfactant to the nonionic surfactant is 1:1-2. The crushing strength of the present invention reaches 71N / particle-80N / particle, and the specific surface area reaches 138m 2 / g‑165m 2 / g, which greatly improves the performance of the alumina catalytic carrier and provides technical support for the long-term, efficient and stable operation of the catalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst carriers, and in particular to a catalyst carrier and a preparation method and application thereof. Background Art

[0002] Most multi-component catalysts consist of an active component, a co-catalyst, and a catalyst support. The catalyst support not only supports the active component but also provides a certain diffusion space for the reactants, ensuring the smooth progress of the catalytic reaction. The performance of the catalyst support has a significant impact on the catalyst's activity, selectivity, heat and mass transfer performance, service life, and production costs.

[0003] Commonly used catalyst supports include alumina, silica gel, activated carbon, pumice, or diatomaceous earth. Among them, alumina-based catalyst supports are widely used due to their high specific surface area, rich porous structure, controllable surface acidity, good thermal stability, and certain adsorption properties.

[0004] As my country's industrial products continue to develop towards high quality, industries such as petrochemicals, coal chemicals, and fine chemicals have increasingly higher requirements for the reaction performance of catalysts, and single-component alumina catalytic carriers can no longer meet the requirements.

[0005] The existing technology (Gao Yi et al., Preparation and application of a hydrocracking catalyst carrier silica gel [J], Ceramics, May 2021, 27-31) found that sodium aluminate solution is used as the aluminum source, water glass is used as the silicon source, and before the carbon dioxide gas is introduced, one-third of silicon oxide is added. After stabilization, carbonization co-precipitation is performed to obtain amorphous silica gel. The amorphous silica gel has a pore volume greater than 0.9 mL / g and a specific surface area greater than 350 m 2 / g, which can be used as a catalyst support, but the document does not focus on the mechanical strength of amorphous silica alumina.

[0006] Chinese patent publication number CN117463309A discloses an alumina carrier and its preparation method and application. The preparation method comprises the following steps: S1: adding an aluminum source to an acid solution for peptization to obtain an aluminum sol; S2: mixing the aluminum sol with a pore-enlarging agent and an organic amine salt template, and adjusting the pH to 4.0-6.0 to obtain a mixed sol; S3: forming the mixed sol obtained in S2 into a sol wet ball by drop-ball molding, and calcining to obtain an alumina carrier. After step S3, the method further comprises a step of loading a tin-containing compound. The prepared alumina carrier has a crushing strength greater than 45N / particle, a maximum pore diameter greater than 30nm, and a specific surface area greater than 180m 2 / g, abrasion loss is less than 0.1%, and the bulk density can be as low as ≤0.4kg / L. It also has the properties of large pore size, high strength and low abrasion. Chinese patent publication number CN118045586A discloses a method for preparing a trimetallic reforming catalyst for alkane reforming to aromatics, wherein the catalyst carrier is a tin-containing alumina carrier, which is obtained by impregnating the alumina carrier with a tin precursor solution or adding the tin precursor solution to a synthetic alumina carrier raw material. The average strength of the prepared tin-containing alumina pellets is 52N / pellet, the pellet diameter is 1.6mm, and the specific surface area is 185m 2 / g.

[0007] The mechanical strength of a catalyst support is crucial to its performance and application. Mechanical strength primarily encompasses crushing strength, abrasion resistance, and corrosion resistance, properties that directly impact the catalyst support's service life and catalytic efficiency. Therefore, finding a catalyst support with a large specific surface area and excellent mechanical strength is crucial for the long-term, efficient, and stable operation of the catalyst. Summary of the Invention

[0008] In order to solve the above technical problems, the present invention provides a catalyst carrier and a preparation method and application thereof.

[0009] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a method for preparing a catalyst support, comprising the following steps:

[0011] Step 1: Adding a silicon source into water to prepare a silica sol;

[0012] Step 2: adding an aluminum source to an acid solution to prepare an aluminum sol;

[0013] Step 3, mixing the aluminum sol with the composite template, tin chloride and silica sol to obtain a slurry;

[0014] Step 4: Prepare the slurry into carrier wet balls, dry and calcine them to obtain the catalyst carrier.

[0015] The composite template agent described in the present invention includes a surfactant and an organic amine, wherein the surfactant is a zwitterionic surfactant and a nonionic surfactant; preferably, the zwitterionic surfactant is a betaine-type zwitterionic surfactant, including at least one of tallow dihydroxyethyl betaine, cocamidopropyl betaine, lauryl amide propyl hydroxysulfobetaine and dodecyl amide propyl betaine; the nonionic surfactant is a polyether-type nonionic surfactant, including at least one of cetyl alcohol polyether-1 and fatty alcohol polyoxyethylene ether; and the organic amine is hexamethylenetetramine.

[0016] In the composite template of the present invention, the ionic part of the zwitterionic surfactant is combined with the nonionic surfactant through hydrogen bond / dipole interaction, so that the hexamethylenetetramine can effectively rebuild the pore structure and fiber network during the growth and rearrangement of the gel fiber, not only forming a dense mesoporous structure, but also significantly improving the mechanical strength of the alumina spheres.

[0017] In some embodiments, the mass ratio of the surfactant to the organic amine is 1:10-20; more preferably 1:12-18; most preferably 1:15.

[0018] In some embodiments, the mass ratio of the zwitterionic surfactant to the nonionic surfactant is 1:1-2; most preferably, it is 1:1.

[0019] In some embodiments, the silicon source in step 1 is at least one of silicon dioxide and water glass; preferably, the mass fraction of the silica sol is 20%-40%.

[0020] In some embodiments, the aluminum source in step 2 is at least one of aluminum hydroxide, pseudo-boehmite, hydrated alumina, aluminum sulfate, sodium aluminate, aluminum chloride and aluminum nitrate; preferably aluminum hydroxide and pseudo-boehmite; further preferably, the mass ratio of the aluminum hydroxide and pseudo-boehmite is 1:1-5; further preferably, it is 1:2-4.

[0021] In some embodiments, the mass fraction of the acid solution in step 2 is 5%-20%, preferably 5%-15%. The acid includes at least one of nitric acid, hydrochloric acid and sulfuric acid, preferably nitric acid.

[0022] In some embodiments, the mass fraction of the aluminum sol in step 2 is 20%-40%, preferably 23%-30%.

[0023] In some embodiments, the composite template in step 3 is 3%-10% by mass of the aluminum sol, preferably 5%-8%.

[0024] In some embodiments, the tin chloride in step 3 is 0.1%-0.5% by mass of the aluminum sol; preferably 0.2%-0.4%.

[0025] In some embodiments, the mass ratio of the aluminum sol to the silica gel solution in step 3 is 1:0.03-0.1; preferably 1:0.06-0.08.

[0026] In some embodiments, the method for preparing the carrier wet balls in step 3 is a conventional technical means in the art, such as a hot oil column ball forming method or an oil-ammonia column ball forming method, and therefore, its specific parameters are not limited.

[0027] In some embodiments, the drying in step 4 is: drying at 100° C.-130° C. for 2 h-6 h; preferably drying at 110° C.-120° C. for 3 h-5 h.

[0028] In some embodiments, the calcination in step 4 is: calcination at 450°C-1000°C for 2h-8h; preferably calcination at 600°C-800°C for 4h-6h.

[0029] In a second aspect, the present invention provides a catalyst carrier prepared by the above preparation method.

[0030] The catalyst carrier of the present invention has a crushing strength of 71N / particle to 80N / particle and a specific surface area of ​​138m 2 / g-165m 2 / g, which greatly improves the performance of the alumina catalytic carrier and provides technical support for the long-term, efficient and stable operation of the catalyst.

[0031] In a third aspect, the present invention provides the use of the above-mentioned preparation method or the above-mentioned catalyst carrier in preparing a catalyst.

[0032] In some embodiments, the catalyst is a dehydrogenation catalyst; preferably a propane dehydrogenation catalyst.

[0033] In a fourth aspect, the present invention provides a dehydrogenation catalyst comprising the above-mentioned catalyst carrier, a main active component and a co-active component.

[0034] In some embodiments, the active component is platinum, and the co-active component is at least one of sodium, potassium, magnesium, tin, lanthanum, cerium, gallium, iron, and cobalt.

[0035] The beneficial effects of the present invention are:

[0036] (1) The ionic part of the zwitterionic surfactant in the composite template of the present invention is combined with the nonionic surfactant through hydrogen bond / dipole interaction, so that the hexamethylenetetramine can effectively rebuild the pore structure and fiber network during the growth and rearrangement of the gel fiber, not only forming a dense mesoporous structure, but also significantly improving the mechanical strength of the alumina ball. At the same time, the addition of silicon is beneficial to improving the structural stability of alumina, and the addition of tin ions can further improve the mechanical strength of the alumina ball.

[0037] (2) Experiments have shown that the combination of the zwitterionic surfactant, the nonionic surfactant and the organic amine hexamethylenetetramine in the present invention produces a synergistic effect on improving the properties of the catalyst carrier, such as the content of irregular spheres, specific surface area, crushing strength and abrasion, and achieves unexpected technical effects.

[0038] (3) The catalyst carrier of the present invention has the following advantages:

[0039] 1) Good sphericity, uniform particle size, and the content of irregular balls is less than 7%;

[0040] 2) High surface finish, wear <1.0%;

[0041] 3) The crushing strength reaches 71N / grain-80N / grain, and the specific surface area reaches 138m 2 / g-165m 2 / g, which greatly improves the performance of the alumina catalytic carrier and provides technical support for the long-term, efficient and stable operation of the catalyst. DETAILED DESCRIPTION

[0042] The description of the following embodiments is only intended to help understand the method of the present invention and its core ideas. It should be noted that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications may be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The following description of the disclosed embodiments enables professionals in this field to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but may be applied to a wider range consistent with the principles and novel features disclosed herein.

[0043] When numerical ranges are given in the examples, it should be understood that, unless otherwise specified herein, both endpoints of each numerical range and any value between the endpoints may be used. Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this invention belongs. Unless otherwise specified, all solvents used in this invention are water, and all temperatures used are room temperature (20-25°C). For example, the silica is fumed silica, purchased from Cabot Corporation in the United States, model CAB-O-SIL M5, and the pseudo-boehmite is purchased from Yangzhou Zhongtianli New Materials Co., Ltd. in China, model ZTL-CAH.

[0044] Example 1

[0045] A method for preparing a catalyst carrier comprises the following steps:

[0046] Step 1: Add silicon dioxide into water to prepare a silica sol with a mass fraction of 20%.

[0047] Step 2: Aluminum hydroxide and pseudo-boehmite are added to a 5% by mass nitric acid solution in a mass ratio of 1:1 to prepare an aluminum sol with a mass fraction of 20%.

[0048] Step 3: Take 100 g of aluminum sol, add 3 g of composite template, 0.1 g of tin chloride and 3 g of silica gel, and stir at 300 rpm for 60 min to obtain a slurry.

[0049] The composite template agent is a surfactant and hexamethylenetetramine in a mass ratio of 1:10; the surfactant is tallow dihydroxyethyl betaine and fatty alcohol polyoxyethylene ether in a mass ratio of 1:1.

[0050] Step 4: drip the slurry into the hot oil column with a needle, solidify it to form a carrier wet ball, dry it at 110° C. for 4 hours, and calcine it at 700° C. for 5 hours to obtain the catalyst carrier.

[0051] Example 2

[0052] A method for preparing a catalyst carrier comprises the following steps:

[0053] Step 1: Add silicon dioxide into water to prepare a silica sol with a mass fraction of 40%.

[0054] Step 2: Aluminum hydroxide and pseudo-boehmite are added to a 20% by mass nitric acid solution in a mass ratio of 1:5 to prepare an aluminum sol with a mass fraction of 40%.

[0055] Step 3: Take 100 g of aluminum sol, add 10 g of composite template, 0.5 g of tin chloride and 10 g of silica gel, and stir at 300 rpm for 60 min to obtain a slurry.

[0056] The composite template agent is a surfactant and hexamethylenetetramine in a mass ratio of 1:20; the surfactant is tallow dihydroxyethyl betaine and cetyl alcohol polyether-1 in a mass ratio of 1:2.

[0057] Step 4: drip the slurry into the hot oil column with a needle, solidify it to form a carrier wet ball, dry it at 110° C. for 4 hours, and calcine it at 700° C. for 5 hours to obtain the catalyst carrier.

[0058] Example 3

[0059] A method for preparing a catalyst carrier comprises the following steps:

[0060] Step 1: Add silicon dioxide into water to prepare a silica sol with a mass fraction of 30%.

[0061] Step 2: Aluminum hydroxide and pseudo-boehmite are added to a 10% by mass nitric acid solution in a mass ratio of 1:3 to prepare an aluminum sol with a mass fraction of 30%.

[0062] Step 3: Take 100 g of aluminum sol, add 6.5 g of composite template, 0.3 g of tin chloride and 7 g of silica gel, and stir at 300 rpm for 30 min to obtain a slurry.

[0063] The composite template agent is a surfactant and hexamethylenetetramine in a mass ratio of 1:15; the surfactant is tallow dihydroxyethyl betaine and cetyl alcohol polyether-1 in a mass ratio of 1:1.

[0064] Step 4: drip the slurry into the hot oil column with a needle, solidify it to form a carrier wet ball, dry it at 110° C. for 4 hours, and calcine it at 700° C. for 5 hours to obtain the catalyst carrier.

[0065] Example 4

[0066] The only difference between this embodiment and embodiment 3 is that the surfactant is cocamidopropyl betaine and fatty alcohol polyoxyethylene ether in a mass ratio of 1:1.

[0067] The remaining steps are the same as in Example 3.

[0068] Example 5

[0069] The only difference between this embodiment and embodiment 3 is that the surfactant is laurylamidopropyl betaine and ceteth-1 in a mass ratio of 1:2.

[0070] The remaining steps are the same as in Example 3.

[0071] Comparative Example 1

[0072] The only difference between this comparative example and Example 3 is that the surfactant is tallow dihydroxyethyl betaine.

[0073] The remaining steps are the same as in Example 3.

[0074] Comparative Example 2

[0075] The only difference between this comparative example and Example 3 is that the surfactant is cetyl alcohol polyether-1.

[0076] The remaining steps are the same as in Example 3.

[0077] Comparative Example 3

[0078] The only difference between this comparative example and Example 3 is that the composite template does not contain a surfactant and is only hexamethylenetetramine.

[0079] The remaining steps are the same as in Example 3.

[0080] Comparative Example 4

[0081] The only difference between this comparative example and Example 3 is that the mass ratio of the surfactant to hexamethylenetetramine in the composite template is 1:25.

[0082] The remaining steps are the same as in Example 3.

[0083] Catalyst support performance evaluation

[0084] 1. Detection of irregular ball content

[0085] The morphology of the catalyst support was analyzed using a CAMSIZER XT particle size analyzer. Images of 100 samples were taken and analyzed for the content of irregular shaped balls.

[0086] 2. Specific surface area detection

[0087] The pore structure and specific surface area parameters of the catalyst support were analyzed using a JW-TB series surface area and pore size analyzer purchased from Beijing Jingwei Gaobo Science and Technology Co., Ltd. Samples were vacuum degassed at 350°C for 4 hours before measurement. The specific surface area was calculated using the BET method, the pore volume was calculated using the BJH model, and the pore size distribution was analyzed using the DFT method.

[0088] 3. Crushing strength test

[0089] The crushing strength of the catalyst carrier was measured using a DL3 intelligent particle strength tester. The values ​​of 50 particles were measured and the average value was taken.

[0090] 4. Wear detection

[0091] The abrasion rate of spherical alumina carrier was measured using a KM-4D particle abrasion tester. 250 g of sample was ground on the abrasion tester for 30 minutes, sieved to remove dust particles, and weighed to calculate the carrier abrasion rate.

[0092] The results are shown in Table 1.

[0093] Table 1

[0094]

[0095] The results show that the content of the irregular spheres in the catalyst supports prepared in Examples 1 to 5 of the present invention is 5.2% to 6.4%, and the specific surface area reaches 138 m 2 / g-165m 2 / g, the crushing strength reaches 71N / grain-80N / grain, and the abrasion is 0.5%-0.8%.

[0096] Comparing the single factor experiments of Comparative Example 3 and Example 3, it can be seen that when the composite template agent is only organic amine, the content of the shaped spheres of the catalyst carrier prepared therefrom reaches 12.8%, and the specific surface area is only 90m 2 / g, crushing strength of 19.5N / particle, and abrasion loss of 5%, which are significantly inferior to those of the catalyst support prepared in Example 3. This indicates that the catalyst support prepared using only organic amine as a template has poor shaped ball content, specific surface area, crushing strength, and abrasion loss.

[0097] Comparison of Comparative Examples 1-2 and 3 shows that when the surfactant in the composite template is only a zwitterionic surfactant or a nonionic surfactant, the content of the heteromorphic spheres in the catalyst support prepared therefrom reaches 56%-61.9%, and the specific surface area is only 85m 2 / g-87m 2 / g, crushing strength of 21.3N / particle-22.8N / particle, and abrasion loss of 4.5%. Compared with organic amine templates, composite templates composed of a single zwitterionic surfactant or nonionic surfactant and an organic amine have a certain negative effect on the irregular ball content and specific surface area of ​​the catalyst support, but have a certain positive effect on crushing strength and abrasion loss, and the magnitude of the effect is not significant. This indicates that composite templates composed of a single zwitterionic surfactant or nonionic surfactant and an organic amine do not significantly improve the irregular ball content, specific surface area, crushing strength, and abrasion loss of the prepared catalyst support compared to organic amine templates alone.

[0098] By comparing Comparative Examples 1 to 3 with Example 3, it can be seen that the combination of the zwitterionic surfactant, the nonionic surfactant and the organic amine hexamethylenetetramine in the present invention produces a synergistic effect on improving the properties of the catalyst carrier, such as the content of irregular balls, specific surface area, crushing strength and abrasion, and achieves unexpected technical effects.

[0099] Comparing the single factor experiments of Comparative Example 4 and Example 3, it can be seen that when only the mass ratio of surfactant and hexamethylenetetramine is changed, which is not within the scope of the present invention, the content of the shaped spheres of the catalyst support prepared therefrom reaches 49.4%, and the specific surface area is only 80m 2 / g, crushing strength of 28.2N / particle, and abrasion of 4.3%, which are significantly inferior to those of the catalyst support prepared in Example 3. This indicates that the mass ratio of surfactant to hexamethylenetetramine has an important influence on the properties of the prepared catalyst support, such as the content of irregular spheres, specific surface area, crushing strength, and abrasion. Only a composite template composed of surfactant and hexamethylenetetramine in a specific mass ratio can achieve the technical effects of the present invention.

[0100] The above further describes the present invention in conjunction with specific embodiments. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. It should be understood by those skilled in the art that the details and forms of the technical solutions of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, and such modifications and replacements shall fall within the scope of protection of the present invention.

Claims

1. A method for preparing a catalyst carrier, characterized in that: The steps include: Step 1: Adding a silicon source into water to prepare a silica sol; Step 2: adding an aluminum source to an acid solution to prepare an aluminum sol; Step 3, mixing the aluminum sol with the composite template, tin chloride and silica sol to obtain a slurry; Step 4: preparing the slurry into a carrier wet ball, drying and calcining the ball to obtain the catalyst carrier; The composite template comprises a surfactant and an organic amine, wherein the surfactant is a zwitterionic surfactant and a nonionic surfactant, and the organic amine is hexamethylenetetramine; The mass ratio of the surfactant to the organic amine is 1:10-20; the mass ratio of the zwitterionic surfactant to the nonionic surfactant is 1:1-2; The zwitterionic surfactant is a betaine-type zwitterionic surfactant, the nonionic surfactant is a polyether-type nonionic surfactant, the betaine-type zwitterionic surfactant is at least one of tallow dihydroxyethyl betaine, cocamidopropyl betaine, lauryl amide propyl hydroxysulfonyl betaine and dodecyl amide propyl betaine; the polyether-type nonionic surfactant is at least one of cetyl alcohol polyether-1 and fatty alcohol polyoxyethylene ether; The mass ratio of the aluminum sol to the silica gel solution in step 3 is 1:0.03-0.

1.

2. The method for preparing a catalyst carrier according to claim 1, wherein The mass ratio of the surfactant to the organic amine is 1:12-18; the mass ratio of the zwitterionic surfactant to the nonionic surfactant is 1:

1.

3. The method for preparing a catalyst carrier according to claim 1, wherein: The aluminum source in step 2 is at least one of aluminum hydroxide, pseudo-boehmite, hydrated aluminum oxide, aluminum sulfate, sodium metaaluminate, aluminum chloride and aluminum nitrate; And / or the mass fraction of the acid solution in step 2 is 5%-20%, and the acid includes at least one of nitric acid, hydrochloric acid and sulfuric acid; And / or the mass fraction of the aluminum sol in step 2 is 20%-40%.

4. The method for preparing a catalyst carrier according to claim 1, wherein The composite template in step 3 is 3%-10% of the mass of the aluminum sol; And / or the tin chloride in step 3 is 0.1%-0.5% of the mass of the aluminum sol.

5. A catalyst support prepared by the method for preparing a catalyst support according to any one of claims 1 to 4.

6. Use of the catalyst carrier according to claim 5 in preparing a catalyst.

7. A dehydrogenation catalyst, characterized in that The catalyst comprises the catalyst carrier according to claim 5, a main active component and a co-active component, wherein the main active component is platinum and the co-active component is at least one of sodium, potassium, magnesium, tin, lanthanum, cerium, gallium, iron and cobalt.

Images