A nickel-based catalyst, a preparation method and application thereof

Abstract

The application relates to the technical field of nickel-based catalysts, and particularly discloses a nickel-based catalyst and a preparation method and application thereof. The nickel-based catalyst provided by the application is composed of the following components in percentage by weight: 45-55% of nickel, 1-10% of molybdenum, 1-10% of cerium, 0.5-5% of silicon, and the balance of aluminum; the specific surface area of the nickel-based catalyst is 150-300 m 2 / g, and the crushing strength is greater than or equal to 15 N / mm. According to the technical scheme, the nickel-based catalyst prepared by reasonably matching the active components has high crushing strength, and the catalyst has good catalytic effect and stability in a method for preparing BDO by BYD hydrogenation reaction.

Description

Technical Field

[0001] This application relates to the technical field of nickel-based catalysts, specifically to a nickel-based catalyst, its preparation method, and its application. Background Technology

[0002] 1,4-Butanediol is an important chemical raw material and intermediate, widely used in polyesters, plasticizers, solvents, and cosmetics. Industrially, 1,4-butanediol (BDO) is often prepared by the catalytic hydrogenation of 1,4-butynediol (BYD). The core of this process lies in the development of high-performance hydrogenation catalysts.

[0003] In existing technologies, nickel-based catalysts have been widely used in the catalytic hydrogenation of 1,4-butynediol to 1,4-butanediol due to their advantages such as high catalytic activity, relatively low cost, and wide availability. However, traditional nickel-based catalysts have several problems in practical applications: on the one hand, nickel grains are prone to sintering and agglomeration during high-temperature reactions, leading to a reduction in active sites and a rapid decline in catalytic activity; on the other hand, carbon deposits generated during the reaction easily adhere to the catalyst surface, clogging active sites and shortening the catalyst's lifespan. Furthermore, nickel-based catalysts used in fixed-bed reactors have poor mechanical properties and are highly susceptible to vibration damage, wear, and contamination when the carrier gas flow rate fluctuates, which can severely clog pipelines and limit their further promotion in industrial production. Therefore, developing a nickel-based catalyst with high catalytic activity, good stability, and controllable cost is of great practical significance. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a nickel-based catalyst, its preparation method, and its application.

[0005] In a first aspect, this application provides a nickel-based catalyst composed of the following components by weight percentage: 45-55% nickel, 1-10% molybdenum, 1-10% cerium, 0.5-5% silicon, with the balance being aluminum; The specific surface area of ​​the nickel-based catalyst is 150-300 m². 2 / g, crushing strength ≥15N / mm.

[0006] In the technical solution of this application, the synergistic effects of the components in the formulation are as follows: Nickel, as the main active component, provides the main hydrogenation active sites; the nickel metal surface has the ability to dissociate and adsorb hydrogen, and can activate C≡C and C=C bonds, making it the main force for the hydrogenation of alkyne and alkene bonds; the high loading of 45-55% ensures that the catalyst has sufficiently dense surface active sites to meet the requirements of high reaction rates. Molybdenum, as the first promoter, can form Ni-Mo alloys or interfaces with Ni. The electronegativity and other properties of Mo can fine-tune the electronic structure of Ni. This ligand effect can moderately weaken the adsorption strength of Ni on unsaturated bonds, avoiding excessive adsorption and deep hydrogenation of intermediate products (such as olefins) at active sites, thereby significantly improving the selectivity of the hydrogenation reaction and promoting the formation of the target product BDO; in addition, the Mo species helps to suppress side reactions such as hydrogenolysis that may occur during hydrogenation, protecting the CO bond from breaking. Cerium, as a secondary promoter / structure enhancer, possesses excellent oxygen storage and release capabilities and redox properties. In the hydrogenation reaction atmosphere, it can activate reactant molecules and promote the migration and release of surface-adsorbed hydrogen species, further improving the overall hydrogenation efficiency. Furthermore, it helps Ni species to disperse more finely and uniformly during subsequent reduction, preventing sintering and improving activity and stability. Aluminum and silicon, as the structural framework and support, provide high specific surface area and abundant pore structure, which is the physical basis for loading high Ni content and ensuring its stable dispersion. Their weak acidity prevents side reactions such as polymerization and coking of BYD or intermediates at strong acid sites. Silicon mainly acts as a binder and structural stabilizer, enhancing the overall mechanical strength of the catalyst. Simultaneously, it neutralizes excess strong acid sites on the support surface, further optimizing surface acidity, suppressing carbon deposition side reactions, and playing a positive role in maintaining selectivity.

[0007] Preferably, the specific surface area of ​​the nickel-based catalyst is 200-280 m². 2 / g, crushing strength ≥18N / mm.

[0008] Preferably, the nickel-based catalyst is composed of the following components by weight percentage: nickel 47-53%, molybdenum 7-10%, cerium 1-4%, silicon 1-4%, with the balance being aluminum.

[0009] Preferably, in the nickel-based catalyst, the molybdenum to cerium ratio is molybdenum / cerium = 2-5.

[0010] Preferably, in the nickel-based catalyst, the molybdenum to cerium ratio is molybdenum / cerium = 3-4.

[0011] In one specific implementation, the molybdenum to cerium ratio in the nickel-based catalyst can be 2, 2.5, 3, 3.5, 3.6, 4, 4.5, or 5.

[0012] Experimental analysis shows that the molybdenum-cerium ratio has a significant impact on the performance of nickel-based catalysts. This application further improves the performance of nickel-based catalysts by controlling the molybdenum-cerium ratio within the aforementioned range.

[0013] In specific implementation schemes, to improve catalytic efficiency, optimize the hydrodynamic performance within the reactor, and meet the needs of different industrial reactors, the LENS technology-printed nickel-based catalyst can be designed and manufactured into various regular structures with specific macroscopic geometries. Specific shapes include, but are not limited to: the nickel-based catalyst can be cylindrical, hollow, clover-shaped, spiral, foamed porous, and honeycomb, etc.

[0014] In a specific implementation, the bulk density of the nickel-based catalyst is 0.4-1.2 g / mL.

[0015] The nickel-based catalysts at the low bulk density end (0.4-0.7 g / mL) correspond to structures such as foamed porous structures and high-porosity honeycomb structures. These catalysts possess extremely high porosity and specific surface area, providing abundant active sites and reducing internal diffusion resistance.

[0016] The nickel-based catalysts have the following bulk density ranges (0.7-1.0 g / mL): corresponding to cloverleaf, hollow ring, spiral, and standard honeycomb shapes. These catalysts achieve a balance between specific surface area, mechanical strength, and bed pressure drop.

[0017] The high bulk density end (1.0-1.2 g / mL) of the nickel-based catalyst corresponds to a solid or microporous cylindrical, thick-walled honeycomb structure. This type of catalyst exhibits the highest mechanical strength and structural stability.

[0018] Secondly, this application provides a method for preparing the nickel-based catalyst, specifically including the following steps in sequence: According to the formula, molybdenum, cerium, silicon and aluminum element powders are mixed to obtain molybdenum-cerium-silicon-aluminum composite element powder. Then, nickel element powder raw material and molybdenum-cerium-silicon-aluminum composite element powder are fed at the same time at a feeding speed of 1-5 g / min to obtain premixed material. The premixed material was 3D printed using LENS technology to obtain an intermediate. The process parameters of the LENS technology were: laser power 220-350W, scanning speed 20-40mm / s, layer thickness 8-25μm, oxygen content <20ppm, and filling spacing 40-70μm. The intermediate is placed in a NaOH solution with a concentration of 1-3 mol / L and soaked at a temperature of 20-80℃ for 2-18 hours. After washing with water, the finished product is obtained.

[0019] In the technical solution of this application, the catalyst preform is directly formed using LENS technology. This method can precisely control the three-dimensional macroscopic structure of the catalyst, optimize the flow and mass transfer of reactants, and significantly improve the overall mechanical strength and anti-breakage ability of the catalyst.

[0020] Preferably, the particle size of the powder raw materials of nickel, molybdenum, cerium, silicon and aluminum is 10-100 μm.

[0021] Preferably, the process parameters of the LENS technology are: laser power 250-300W, scanning speed 25-35mm / s, layer thickness 15-20μm, oxygen content <20ppm, and filling spacing 40-50μm.

[0022] Preferably, the soaking conditions are: soaking temperature 30-45℃ and soaking time 4-12h.

[0023] Thirdly, this application provides the application of the nickel-based catalyst in olefin hydrogenation, nitro hydrogenation, and aldehyde / ketone hydrogenation.

[0024] Fourthly, this application provides a method for preparing BDO by hydrogenation of BYD, wherein the catalyst described above is used in the method, and the process parameters are: controlling the concentration of 1,4-butynediol in the BYD aqueous solution to be 20-50 wt%, and the weight hourly space velocity to be 0.01-10 h⁻¹. -1 The molar ratio of hydrogen to 1,4-butynediol in the BYD aqueous solution is (2-5):1; the hydrogenation reaction temperature is 80-150℃ and the reaction pressure is 26-29MPa.

[0025] In summary, the technical solution of this application has the following effects: Using the technical solution of this application, a nickel-based catalyst prepared by reasonably combining active components has high crushing strength, and the catalyst has good catalytic effect and stability in the method of preparing BDO by the hydrogenation reaction of BYD.

[0026] The nickel-based catalyst provided in this application has a framework structure, which can serve as the main mechanical structure and has certain mechanical properties, thus avoiding the problems of easy breakage and rapid deactivation of traditional catalysts.

[0027] The LENS preparation method provided in this application allows for the design and customization of the nickel-based catalyst product, offering high flexibility. For example, it can be added according to different reactor designs, improving its service life. The nickel-based catalyst product obtained using 3D printing in this application can be stored at room temperature, is easy to transport, and reduces costs. Detailed Implementation

[0028] The present application will be further described in detail below with reference to embodiments, comparative examples and performance test results. These embodiments should not be construed as limiting the scope of protection claimed in this application. Example Examples 1-9

[0029] Examples 1-9 provide a nickel-based catalyst and its preparation method, respectively.

[0030] The difference in the above embodiments is that the weight percentage of each raw material component in the nickel-based catalyst is different, as shown in Table 1.

[0031] The preparation method of the nickel-based catalyst in the above embodiments is as follows: According to the formula, molybdenum, cerium, silicon and aluminum element powders are mixed to obtain molybdenum-cerium-silicon-aluminum composite element powder. Then, nickel element powder raw material and molybdenum-cerium-silicon-aluminum composite element powder are fed at the same time at a feeding speed of 2g / min to obtain premixed material.

[0032] The premixed material was 3D printed using LENS technology to obtain an intermediate (a cylindrical particle with a bottom diameter of 5mm and a height of 5mm). The process parameters of LENS technology were: laser power 280W, scanning speed 30mm / s, layer thickness 15μm, oxygen content <20ppm, and filling spacing 55μm.

[0033] The intermediate was placed in a 2 mol / L NaOH solution and soaked at 40°C for 8 hours. It was then washed with deionized water at 50°C until the pH of the solution was 7-9, thus obtaining the final product. Comparative Example Comparative Examples 1-5

[0034] Comparative Examples 1-5 each provide a nickel-based catalyst and its preparation method.

[0035] The difference between the above comparative example and Example 3 is that the weight percentage of each raw material component in the nickel-based catalyst is different, as shown in Table 1.

[0036] In Comparative Example 1, molybdenum was replaced with an equal amount of copper.

[0037] In Comparative Example 2, cerium was replaced with an equal amount of cobalt.

[0038] In Comparative Example 3: the amount of molybdenum was reduced, the amount of cerium was increased, and the amount of silicon was reduced.

[0039] In Comparative Example 4: the amount of molybdenum was increased, the amount of cerium was decreased, and the amount of silicon was increased.

[0040] In Comparative Example 5: no silicon was added, and an equal amount of aluminum was used instead of silicon.

[0041] All other process parameters in the above comparative examples are the same as those in Example 3.

[0042] Table 1. Amounts of each raw material component in Examples 1-9 and Comparative Examples 1-5 Performance testing

[0043] (1) Specific surface area Test method: The specific surface area of ​​the sample was determined using a specific surface area analyzer, referring to the national standard GB / T24533-2009, based on N2 adsorption measurement and the BET method.

[0044] (2) Crushing strength Test method: The test shall be conducted in accordance with the provisions of ASTM D4179.

[0045] (3) Catalytic activity of the catalyst Detection method: The nickel-based catalysts prepared in the examples and comparative examples were placed in an adiabatic fixed-bed reactor for the hydrogenation reaction of BYD to BDO. The hydrogenation reaction conditions were as follows: the 1,4-butynediol aqueous solution contained 35% 1,4-butynediol by weight, the pH value of the 1,4-butynediol aqueous solution was 5.5, and the weight hourly space velocity of the 1,4-butynediol aqueous solution was 1.0 h⁻¹. -1 The molar ratio of hydrogen gas to 1,4-butynediol in an aqueous solution was 3:1. The hydrogenation reaction was carried out at a temperature of 120°C and a pressure of 28 MPa. After the reaction was completed, the products were analyzed.

[0046] (4) Stability of the catalyst The catalysts prepared in the examples and comparative examples were used for 100 hours in the BYD hydrogenation to BDO experiment to test the catalytic performance and evaluate the stability of the catalysts. BYD feedstock conversion stability = BYD feedstock conversion after 100 hours of catalyst use / BYD feedstock conversion of the initial catalyst × 100%; BYD product selectivity stability = BYD product selectivity after 100 hours of catalyst use / BYD product selectivity of the initial catalyst × 100%.

[0047] Test results are shown in Table 2.

[0048] Table 2 Performance test results of catalysts in the examples and comparative examples

[0049] As shown in Table 2, the nickel-based catalyst prepared using the technical solution of this application exhibits high breakage strength. In the method of preparing BDO by the hydrogenation reaction of BYD in a fixed-bed reactor, the BYD conversion rate is >99% and the BDO selectivity is >97%. Furthermore, after 100 hours of use in the BYD hydrogenation reaction to prepare BDO experiment, the catalyst demonstrated good stability. This indicates that the nickel-based catalyst prepared in this application has promising application prospects and significant economic benefits.

[0050] By comparing the test results of Example 3 and Comparative Examples 1-5, it can be seen that in Comparative Example 1, an equal amount of copper was used to replace molybdenum; in Comparative Example 2, an equal amount of cobalt was used to replace cerium; in Comparative Example 3, the amount of molybdenum was reduced, the amount of cerium was increased, and the amount of silicon was reduced; in Comparative Example 4, the amount of molybdenum was increased, the amount of cerium was reduced, and the amount of silicon was increased; and in Comparative Example 5, no silicon was added, and an equal amount of aluminum was used to replace silicon. The resulting nickel-based catalysts exhibited poor performance. In contrast, this application strictly controls the composition of the nickel-based catalyst to the following weight percentages: nickel 45-55%, molybdenum 1-10%, cerium 1-10%, silicon 0.5-5%, with the balance being aluminum, thus preparing a nickel-based catalyst with excellent catalytic activity and stability.

[0051] Comparing the test results of Examples 1-7, it can be seen that the molybdenum / cerium ratio has a significant impact on the performance of nickel-based catalysts. This application utilizes a molybdenum / cerium ratio of 2-5 to further improve the performance of nickel-based catalysts.

[0052] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A nickel-based catalyst, characterized in that, It consists of the following components by weight percentage: nickel 45-55%, molybdenum 1-10%, cerium 1-10%, silicon 0.5-5%, with the balance being aluminum; The specific surface area of ​​the nickel-based catalyst is 150-300 m². 2 / g, crushing strength ≥15N / mm.

2. The nickel-based catalyst according to claim 1, characterized in that, It consists of the following components by weight percentage: nickel 47-53%, molybdenum 7-10%, cerium 1-4%, silicon 1-3%, with the balance being aluminum.

3. The nickel-based catalyst according to claim 1, characterized in that, The molybdenum to cerium ratio is molybdenum / cerium = 2-5.

4. The nickel-based catalyst according to claim 1, characterized in that, The shape of the nickel-based catalyst is selected from any one of the following: cylindrical, hollow, clover-shaped, spiral, foamed porous, honeycomb.

5. The method for preparing the nickel-based catalyst according to any one of claims 1-4, characterized in that, Specifically, the following steps are performed sequentially: According to the formula, molybdenum, cerium, silicon and aluminum element powders are mixed to obtain molybdenum-cerium-silicon-aluminum composite element powder. Then, nickel element powder raw material and molybdenum-cerium-silicon-aluminum composite element powder are fed at the same time at a feeding speed of 1-5 g / min to obtain premixed material. The premixed material was 3D printed using LENS technology to obtain an intermediate. The process parameters of the LENS technology were: laser power 220-350W, scanning speed 20-40mm / s, layer thickness 8-25μm, oxygen content <20ppm, and filling spacing 40-70μm. The intermediate is placed in a NaOH solution with a concentration of 1-3 mol / L and soaked at a temperature of 20-80℃ for 2-18 hours. After washing with water, the finished product is obtained.

6. The method for preparing the nickel-based catalyst according to claim 5, characterized in that, The particle size of the powder raw materials containing nickel, molybdenum, cerium, silicon, and aluminum is 10-100 μm.

7. The method for preparing the nickel-based catalyst according to claim 5, characterized in that, The process parameters for the LENS technology are: laser power 250-300W, scanning speed 25-35mm / s, layer thickness 15-20μm, oxygen content <20ppm, and filling spacing 40-50μm.

8. The method for preparing the nickel-based catalyst according to claim 5, characterized in that, The conditions for the soaking treatment are: soaking temperature 30-45℃ and soaking time 4-12h.

9. The application of a nickel-based catalyst as described in any one of claims 1-4 in olefin hydrogenation, nitro hydrogenation, and aldehyde / ketone hydrogenation.

10. A method for preparing BDO by hydrogenation of BYD, characterized in that, The method uses the catalyst described in any one of claims 1-4, and the process parameters are as follows: the concentration of 1,4-butynediol in the BYD aqueous solution is controlled at 20-50 wt%, and the weight hourly space velocity is 0.01-10 h⁻¹. -1 The molar ratio of hydrogen to 1,4-butynediol in the BYD aqueous solution is (2-5):1; the hydrogenation reaction temperature is 80-150℃ and the reaction pressure is 26-29MPa.

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