A composite Hf-containing support material loaded CuO catalyst, its preparation and application in acetylene hydrogenation reaction

Abstract

This invention discloses a CuO catalyst supported on a composite Hf-containing support material, its preparation, and its application in the hydrogenation reaction of acetylene. The preparation method of the CuO catalyst supported on the composite Hf-containing support material includes the following steps: preparing a composite Hf-containing support material; loading Cu(OH)₂ onto the composite Hf-containing support material using a wet impregnation process; and then calcining under air atmosphere to obtain the CuO catalyst supported on the composite Hf-containing support material. This invention provides the application of the CuO catalyst supported on the composite Hf-containing support material in the selective hydrogenation reaction of acetylene, exhibiting good stability and high activity.

Description

Technical Field

[0001] This invention pertains to the field of catalyst preparation technology, specifically relating to a CuO catalyst supported on a composite Hf-containing support material, its preparation method, and its application in the hydrogenation reaction of acetylene. Background Technology

[0002] Ethylene is one of the largest-volume chemical products and a core raw material for the petrochemical industry. It is widely used in synthetic plastics, rubber, fibers, pharmaceuticals, pesticides, and dyes, making the ethylene industry a vital part of the national economy. Currently, my country's total ethylene production cannot meet domestic demand, and the industry still needs continuous development and strengthening. Ethylene is mainly produced through the thermal cracking of naphtha and diesel oil. However, the production of ethylene generates 0.3%–3% acetylene by volume. These trace amounts of acetylene can poison the Ziegler-Natta catalyst for polyethylene, reducing its activity and lifespan, as well as the quality of the polyethylene. Therefore, removing acetylene from ethylene feedstock is crucial. Methods for removing trace amounts of acetylene from ethylene include ammoniation, cryogenic distillation, solvent absorption, and catalytic hydrogenation. Catalytic hydrogenation selectively hydrogenates acetylene to produce ethylene, thus achieving a net ethylene gain. It has advantages such as simple process flow, low energy consumption, environmental friendliness, and high atom utilization, and is currently the most commonly used method in industry.

[0003] Palladium (Pd), a noble metal, is a commonly used selective hydrogenation catalyst. In Pd catalytic hydrogenation, the selectivity for olefins strongly depends on the conversion of alkanes; when alkanes are completely converted, the formation of unwanted alkanes is significantly accelerated. In practice, the ratio of hydrogen to acetylene in the feed must be strictly adjusted to minimize ethane production and avoid thermal runaway of the catalyst bed. In some cases, controlling the amount of CO to suppress the adsorption of ethylene by high acetylene conversion further complicates the process and reactor operation. Another disadvantage of palladium-containing catalysts is their high cost. Therefore, there is an urgent need to develop more selective catalysts, preferably non-noble metals. As alternative non-noble metal catalysts, Ni, Cu, Fe alloys, intermetallic compounds (Ni3Ga, NizSn2, and Al) are considered. 13 The selective hydrogenation of acetylene using Fe4 and metal oxides (CeO2) was studied. Currently, copper-based catalysts used in acetylene hydrogenation reactions are generally copper single atoms or copper nanoparticles, or added as a second metal. Copper oxide is widely used in other reactions, but in acetylene hydrogenation, copper oxide catalysts exhibit relatively poor acetylene conversion and stability.

[0004] In summary, improving the activity and stability of copper-based catalysts in the selective hydrogenation of acetylene remains a significant challenge. Therefore, it is of great importance to invent a copper-based catalyst that can be applied to the selective hydrogenation of acetylene and possesses good specific surface area, stability, and activity. Summary of the Invention

[0005] The purpose of this invention is to address the problems of low acetylene conversion and poor stability of copper oxide catalysts currently used for the selective hydrogenation of acetylene. This invention provides a method for preparing a CuO catalyst supported on a composite Hf-containing carrier material and its application in the acetylene hydrogenation reaction, which exhibits better stability and higher activity.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing a CuO catalyst supported on a composite Hf-containing support material, comprising the following steps:

[0008] Step 1: Grind the initial mixture of Hf, Si and boron in a ball mill to obtain a well-mixed mixture; wherein the molar ratio of Hf to boron is 5.5-7:11, and the molar ratio of silicon to boron is 1-12.6:11.

[0009] Step 2: The mixture obtained in Step 1 is dispersed in a ball mill under humid conditions using ethanol as a dispersant. The slurry is then homogenized again using an ultrasonic apparatus and dried by rotary evaporation to obtain a dry powder mixture.

[0010] Step 3: The dried powder mixture is pressed into cylindrical particles of a certain size to match the reaction cell of the self-propagating high-temperature synthesizer. The cylindrical particles are then placed into the reaction cell of the self-propagating high-temperature synthesizer and heated to 1800℃ for 10–30 min. According to literature reports, if the reaction temperature is below 1800℃, the HfB2-HfSi2 support cannot be generated, and if the reaction temperature is above 1800℃, the HfB2-HfSi2 support structure is prone to collapse. Therefore, the temperature here is set to 1800℃.

[0011] Step 4: Grind the cooled cylindrical particles in a ball mill to obtain a composite Hf-containing carrier material;

[0012] Step 5: Load Cu(OH)2 onto the composite Hf-containing support material using wet impregnation, and then calcine it in air to obtain the CuO catalyst supported on the composite Hf-containing support material.

[0013] In this invention, Hf, silicon, and boron are all commercially available products. Furthermore, the purity of Hf is >99.6%, and the average particle size is <44 μm; the boron is amorphous boron with a purity >95% and an average particle size <9 μm; and the purity of silicon is >99%, and the average particle size is <44 μm.

[0014] Furthermore, in step one, the ball milling speed is 200-400 r / min, and the time is 1-3 h.

[0015] Furthermore, in step one, the molar ratio of Hf to boron in the starting mixture for synthesizing the Hf-containing composite support material is 5.5-6.3:11, and the molar ratio of silicon to boron is 1-12.6:11, more preferably 1-3:11, to ensure that the reaction can proceed and that residual boron is present. The catalyst obtained within this preferred range exhibits better catalytic performance.

[0016] Furthermore, in step two, the operating conditions for dispersion using a ball mill are: ball mill speed of 200-400 r / min and time of 0.5-3 h.

[0017] Furthermore, the ultrasonic homogenization time in step two is 30–60 min.

[0018] Furthermore, in step four, the ball milling speed is 200–400 r / min, and the time is 2–4 h.

[0019] Furthermore, in step five, the copper loading in the CuO catalyst supported by the composite Hf-containing support material is 3–6 wt.%, based on a support mass of 100%. This loading is calculated under the ideal condition that the copper element in the precursor can be fully loaded.

[0020] Furthermore, step five is implemented as follows:

[0021] Pour an appropriate amount of NaOH or KOH solution into the reaction vessel, then add a precursor solution containing copper ions, and stir thoroughly to generate Cu(OH)2; add the composite Hf-containing support material prepared in step three to the resulting mixture, and stir magnetically to ensure thorough impregnation. After stirring, filter off the upper liquid and repeatedly wash the residue with deionized water until neutral, then wash thoroughly with anhydrous ethanol, and then dry the residue. Finally, place it in a muffle furnace and calcine it in air to obtain the CuO catalyst supported by the composite Hf-containing support material.

[0022] Furthermore, in step five, the precursor containing copper ions can be either copper nitrate or copper chloride.

[0023] Furthermore, the concentration of the added NaOH or KOH solution is 4-6 mol / L. The term "appropriate amount" in "appropriate amount of NaOH or KOH solution" means that the amount of NaOH or KOH solution added is sufficient to completely submerge the carrier, and that the amount of NaOH or KOH added is sufficient to completely convert the copper ions in the copper-containing precursor into Cu(OH)₂.

[0024] Furthermore, in step five, the magnetic stirring speed is 200–400 r / min, and the stirring time is 6–12 h.

[0025] Furthermore, in step five, the residue is dried using high-voltage battery drying technology, with an electric field strength of 10–20 kV / cm. This drying method can significantly improve the catalytic performance of the catalyst.

[0026] In step five of this invention, copper oxide catalyst is obtained by calcination in a muffle furnace. Since the reaction of Cu(OH)2 to generate CuO and H2O begins at around 200℃, and Cu(OH)2 can be completely decomposed into CuO at 400℃, in step five, the calcination temperature of the muffle furnace is ≥400℃ and the calcination time is 1 to 3 hours.

[0027] In a second aspect, the present invention provides a CuO catalyst supported on a composite Hf-containing support material prepared according to the preparation method described in the first aspect.

[0028] Thirdly, the present invention provides the application of the CuO catalyst supported by the composite Hf-containing support material in the selective hydrogenation of acetylene to ethylene.

[0029] The specific application is as follows: In a fixed-bed reactor, the CuO catalyst supported by the composite Hf-containing support material is loaded, and the raw material gases H2 and C2H2 are introduced. The reaction temperature is controlled at 120-140℃ to obtain ethylene.

[0030] Furthermore, the molar ratio of the raw material gases is n(H2):n(C2H2) = 1:1 to 2:1, and the acetylene volume hourly space velocity is 5000 to 6000 h⁻¹. -1 .

[0031] Compared with the prior art, the present invention has the following innovations and technical advantages:

[0032] (1) Compared with the traditional HfB2-HfSi2 preparation process, the preparation method of the composite Hf-containing support material of the present invention adds ultrasonic treatment, secondary mixing, self-propagating high-temperature reaction and ball milling process, which makes the prepared material more suitable as a support for the selective addition of copper hydroxide catalyst to acetylene, and significantly improves the acetylene conversion rate and catalyst stability.

[0033] (2) The present invention uses high voltage electric field technology to dry the catalyst, which has high drying efficiency and low energy consumption. At the same time, it can enable water molecules to move freely on the inner and outer surfaces of the catalyst, forming more channels, increasing the specific surface area of ​​the catalyst, and thus improving its catalytic performance.

[0034] (3) The reagents used in the preparation method of CuO catalyst supported by composite Hf carrier material of the present invention are readily available, non-toxic and harmless, simple in process, low in cost, and easy to mass-produce and industrialize.

[0035] (4) The CuO catalyst supported by the composite Hf-containing support material prepared in this invention has excellent mechanical strength. It has excellent catalytic activity and ethylene selectivity in the selective hydrogenation of acetylene to ethylene, and good stability. Detailed Implementation

[0036] The present invention will be illustrated below with specific embodiments. It should be noted that the embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention, which is not limited thereto in any way. Those skilled in the art can make some non-essential improvements and adjustments based on the above description of the invention.

[0037] The Hf used in this embodiment of the invention has a purity of 99.8% and an average particle size of 15 μm; the boron is amorphous boron with a purity of 99.9% and an average particle size of 6 μm; the silicon has a purity of 99.9% and an average particle size of 10 μm.

[0038] Example 1

[0039] (1) Preparation of the carrier: 224.91 g of Hf, 14.56 g of Si, and 23.782 g of boron were weighed and placed in a ball mill and ground for 2 h at a speed of 300 r / min to obtain a well-mixed mixture. The mixture was then dispersed in a ball mill for 30 min under humid conditions with an appropriate amount of ethanol as a dispersant, ensuring the ethanol completely covers the mixture. The slurry was then homogenized again for 60 min using an ultrasonic instrument with an ultrasonic input power of 50 W and then dried by rotary evaporation. The dried powder mixture was then pressed into cylindrical particles (approximately 11 mm in diameter and 20 mm in thickness). The cylindrical particles were then placed in a self-propagating high-temperature synthesizer and heated to 1800 °C for 30 min. The cooled cylindrical particles were then ground in a ball mill for 4 h at a speed of 300 r / min to obtain a composite Hf-containing carrier material.

[0040] (2) Catalyst preparation: 4.7 ml of 4M NaOH solution was poured into a petri dish, followed by 11.72 ml of 0.15 g / ml copper nitrate solution. The mixture was stirred thoroughly to generate Cu(OH)₂. 10 g of the prepared composite Hf-containing support material was added to the resulting mixture. The mixture was stirred magnetically at 200 r / min for 6 h to ensure thorough impregnation. After stirring, the supernatant was filtered off, and the residue was repeatedly washed with deionized water until neutral. Then, it was thoroughly washed with anhydrous ethanol. The residue was then dried in a high-voltage electric field drying device with an electric field strength of 20 kV / cm, and then calcined in a muffle furnace at 400 °C for 2 h to obtain the CuO catalyst supported on the composite Hf-containing support material.

[0041] (3) Application of the catalyst in the selective hydrogenation of acetylene: 0.25 g of this catalyst was applied to the selective hydrogenation of acetylene in a fixed-bed reactor under the following reaction conditions: temperature 120℃, n(HCl):n(H2) = 1:2, and acetylene space velocity 6000 h⁻¹. -1 In the initial stage of the reaction, the acetylene conversion rate was 99.4% and the ethylene selectivity was 99.5%; after 1000 hours of reaction, the acetylene conversion rate was 98.2% and the ethylene selectivity was 99.0%.

[0042] Example 2

[0043] (1) Preparation of the carrier: 196.35 g Hf, 5.6 g Si, and 23.782 g boron were weighed into a starting mixture and ground in a ball mill for 2 hours at a speed of 300 r / min to obtain a well-mixed mixture. The mixture was then dispersed in a ball mill for 30 minutes under humid conditions with an appropriate amount of ethanol as a dispersant, ensuring the ethanol completely covers the mixture. The slurry was then homogenized again using an ultrasonic instrument for 60 minutes at an ultrasonic input power of 50 W, followed by rotary evaporation drying. The dried powder mixture was then pressed into cylindrical particles (approximately 11 mm in diameter and 20 mm thick). These cylindrical particles were then placed in a self-propagating high-temperature synthesizer and heated to 1800 °C for 30 minutes. The cooled cylindrical particles were then ground in a ball mill for 3 hours at a speed of 300 r / min to obtain a composite Hf-containing carrier material.

[0044] (2) Catalyst preparation: 4.7 ml of 4M NaOH solution was poured into a petri dish, followed by 11.72 ml of 0.15 g / ml copper nitrate solution. The mixture was stirred thoroughly to generate Cu(OH)₂. 10 g of the prepared composite Hf-containing support material was added to the resulting mixture. The mixture was stirred magnetically at 200 r / min for 6 h to ensure thorough impregnation. After stirring, the supernatant was filtered off, and the residue was repeatedly washed with deionized water until neutral. Then, it was thoroughly washed with anhydrous ethanol. The residue was then dried in a high-voltage electric field drying device with an electric field strength of 15 kV / cm, and then calcined in a muffle furnace at 400 °C for 2 h to obtain the CuO catalyst supported on the composite Hf-containing support material.

[0045] (3) Application of the catalyst in the selective hydrogenation of acetylene: 0.25 g of this catalyst was applied to the selective hydrogenation of acetylene in a fixed-bed reactor under the following reaction conditions: temperature 120℃, n(HCl):n(H2) = 1:2, and acetylene space velocity 6000 h⁻¹. -1 In the initial stage of the reaction, the acetylene conversion rate was 98.9% and the ethylene selectivity was 99.1%; after 1000 hours of reaction, the acetylene conversion rate was 98.1% and the ethylene selectivity was 98.6%.

[0046] Example 3

[0047] (1) Preparation of the carrier: 196.35 g Hf, 5.6 g Si, and 23.782 g boron were weighed and placed in a ball mill for 2 hours at a speed of 300 r / min to obtain a well-mixed mixture. The mixture was then dispersed in a ball mill for 30 minutes under humid conditions using an appropriate amount of ethanol as a dispersant, ensuring the ethanol completely covers the mixture. The slurry was then homogenized again for 30 minutes using an ultrasonic instrument with an ultrasonic input power of 50 W, followed by rotary evaporation drying. The dried powder mixture was then pressed into cylindrical particles (approximately 11 mm in diameter and 20 mm in thickness). These cylindrical particles were then placed in a self-propagating high-temperature synthesizer and heated to 1800 °C for 20 minutes. The cooled cylindrical particles were then ground in a ball mill for 2 hours at a speed of 300 r / min to obtain the composite Hf-containing carrier material.

[0048] (2) Catalyst preparation: 4.7 ml of 4M NaOH solution was poured into a petri dish, followed by 11.72 ml of 0.15 g / ml copper nitrate solution. The mixture was stirred thoroughly to generate Cu(OH)₂. 10 g of the prepared composite Hf-containing support material was added to the resulting mixture. The mixture was stirred magnetically at 200 r / min for 6 h to ensure thorough impregnation. After stirring, the supernatant was filtered off, and the residue was repeatedly washed with deionized water until neutral. Then, it was thoroughly washed with anhydrous ethanol. The residue was then dried in a high-voltage electric field drying device with an electric field strength of 15 kV / cm, and then calcined in a muffle furnace at 400 °C for 2 h to obtain the CuO catalyst supported on the composite Hf-containing support material.

[0049] (3) Application of the catalyst in the selective hydrogenation of acetylene: 0.25 g of this catalyst was applied to the selective hydrogenation of acetylene in a fixed-bed reactor under the following reaction conditions: temperature 120℃, n(HCl):n(H2) = 1:2, and acetylene space velocity 6000 h⁻¹. -1 In the initial stage of the reaction, the acetylene conversion rate was 98.7% and the ethylene selectivity was 98.9%; after 1000 hours of reaction, the acetylene conversion rate was 97.5% and the ethylene selectivity was 97.8%.

[0050] Example 4

[0051] (1) Preparation of the carrier: 196.35 g Hf, 5.6 g Si, and 23.782 g boron were weighed and placed in a ball mill for 2 hours at a speed of 300 r / min to obtain a well-mixed mixture. The mixture was then dispersed in a ball mill for 30 minutes under humid conditions using an appropriate amount of ethanol as a dispersant, ensuring the ethanol completely covers the mixture. The slurry was then homogenized again for 30 minutes using an ultrasonic instrument with an ultrasonic input power of 50 W, followed by rotary evaporation drying. The dried powder mixture was then pressed into cylindrical particles (approximately 11 mm in diameter and 20 mm in thickness). These cylindrical particles were then placed in a self-propagating high-temperature synthesizer and heated to 1800 °C for 20 minutes. The cooled cylindrical particles were then ground in a ball mill for 2 hours at a speed of 300 r / min to obtain the composite Hf-containing carrier material.

[0052] (2) Catalyst preparation: 2.4 ml of 4M NaOH solution was poured into a petri dish, followed by 5.86 ml of 0.15 g / ml copper nitrate solution. The mixture was stirred thoroughly to generate Cu(OH)₂. 10 g of the prepared composite Hf-containing support material was added to the resulting mixture. The mixture was stirred magnetically at 200 r / min for 6 h to ensure thorough impregnation. After stirring, the supernatant was filtered off, and the residue was repeatedly washed with deionized water until neutral. Then, it was thoroughly washed with anhydrous ethanol. The residue was then dried in a high-voltage electric field drying device with an electric field strength of 15 kV / cm, and then calcined in a muffle furnace at 400 °C for 2 h to obtain the CuO catalyst supported on the composite Hf-containing support material.

[0053] (3) Application of the catalyst in the selective hydrogenation of acetylene: 0.25 g of this catalyst was applied to the selective hydrogenation of acetylene in a fixed-bed reactor under the following reaction conditions: temperature 120℃, n(HCl):n(H2) = 1:2, and acetylene space velocity 6000 h⁻¹. -1 In the initial stage of the reaction, the acetylene conversion rate was 97.4% and the ethylene selectivity was 98.4%; after 1000 hours of reaction, the acetylene conversion rate was 96.5% and the ethylene selectivity was 97.8%.

[0054] Comparative Example 1

[0055] Comparative Example 1 demonstrates, by comparing it with Example 1, that the HfB2-HfSi2 support significantly improves the activity and stability of the copper oxide catalyst in the selective hydrogenation reaction of acetylene compared to the γ-Al2O3 support.

[0056] (1) Preparation of the support: Grind γ-Al2O3 into 40-60 mesh for later use.

[0057] (2) Catalyst preparation: 4.7 ml of 4M NaOH solution was poured into a petri dish, followed by 11.72 ml of 0.15 g / ml copper nitrate solution. The mixture was stirred thoroughly to generate Cu(OH)2. 10 g of the prepared γAl2O3 support was added to the resulting mixture, and the mixture was stirred magnetically at 200 r / min for 6 h to ensure thorough impregnation. After stirring, the supernatant was filtered off, and the residue was repeatedly washed with deionized water until neutral. Then, it was thoroughly washed with anhydrous ethanol. The residue was then dried in a high-voltage electric field drying device with an electric field strength of 20 kV / cm, and then calcined in a muffle furnace at 400 °C for 2 h to obtain the CuO / γAl2O3 catalyst for the selective hydrogenation of acetylene.

[0058] (3) Application of the catalyst in the selective hydrogenation of acetylene: 0.25 g of this catalyst was applied to the selective hydrogenation of acetylene in a fixed-bed reactor under the following reaction conditions: temperature 120℃, n(HCl):n(H2) = 1:2, and acetylene space velocity 6000 h⁻¹. -1 Initially, the acetylene conversion rate was 60.4%, and the ethylene selectivity was 98.9%; after 1000 hours of reaction, the acetylene conversion rate was 44.2%, and the ethylene selectivity was 98.1%.

[0059] Comparative Example 2

[0060] (1) Preparation of the carrier: 240.975 g of Hf, 19.6 g of Si and 23.782 g of boron were weighed and placed in a ball mill and ground for 2 h at a speed of 300 r / min to obtain a well-mixed mixture. The mixture was then dispersed in a ball mill for 30 min under humid conditions with an appropriate amount of ethanol as a dispersant, just enough to cover the mixture. The slurry was then homogenized again by ultrasonication for 60 min at an ultrasonic input power of 50 W and then dried by rotary evaporation. The dried powder mixture was pressed into cylindrical particles (approximately 11 mm in diameter and 20 mm in thickness). The cylindrical particles were then placed in a self-propagating high-temperature synthesizer and heated to 1800 °C for 30 min. The cooled cylindrical particles were then placed in a ball mill and ground for 4 h at a speed of 300 r / min to obtain a composite Hf-containing carrier material.

[0061] (2) Catalyst preparation: 4.7 ml of 4M NaOH solution was poured into a petri dish, followed by 11.72 ml of 0.15 g / ml copper nitrate solution. The mixture was stirred thoroughly to generate Cu(OH)₂. 10 g of the prepared composite Hf-containing support material was added to the resulting mixture. The mixture was stirred magnetically at 200 r / min for 6 h to ensure thorough impregnation. After stirring, the supernatant was filtered off, and the residue was repeatedly washed with deionized water until neutral. Then, it was thoroughly washed with anhydrous ethanol. The residue was then dried in a high-voltage electric field drying device with an electric field strength of 20 kV / cm, and then calcined in a muffle furnace at 400 °C for 2 h to obtain the CuO catalyst supported on the composite Hf-containing support material.

[0062] (3) Application of the catalyst in the selective hydrogenation of acetylene: 0.25 g of this catalyst was applied to the selective hydrogenation of acetylene in a fixed-bed reactor under the following reaction conditions: temperature 120℃, n(HCl):n(H2) = 1:2, and acetylene space velocity 6000 h⁻¹. -1 In the initial stage of the reaction, the acetylene conversion rate was 75.4% and the ethylene selectivity was 98.8%; after 1000 hours of reaction, the acetylene conversion rate was 64.2% and the ethylene selectivity was 97.6%.

[0063] Comparative Example 2, compared with Example 1, demonstrates that the Hf / boron molar ratio during support preparation has a significant impact on the activity and stability of the catalyst in the selective hydrogenation of acetylene. However, the catalyst prepared in Comparative Example 2 still exhibits better catalytic performance than the CuO / γAl2O3 catalyst prepared in Comparative Example 1.

[0064] Comparative Example 3

[0065] Comparative Example 3 demonstrates, by comparing it with Example 1, that the addition of a self-propagating high-temperature reaction operation during the preparation of the support can significantly improve the catalytic activity and stability of the catalyst in the selective hydrogenation of acetylene.

[0066] (1) Preparation of the support: 224.91 g of Hf, 14.56 g of Si, and 23.782 g of boron were weighed and ground in a ball mill for 2 hours at a speed of 300 r / min to obtain a well-mixed mixture. The mixture was then dispersed in a ball mill for 30 minutes under humid conditions with an appropriate amount of ethanol as a dispersant, ensuring the ethanol completely covers the mixture. The ball mill was then used to homogenize the slurry again for 60 minutes at an ultrasonic input power of 50 W, followed by rotary evaporation drying. The dried powder mixture was then pressed into cylindrical particles (approximately 11 mm in diameter and 20 mm thick). The cylindrical particles were then placed back into a graphite crucible, heated to 1800 °C and held for 2 hours, followed by natural cooling. The resulting composite Hf-containing support material was obtained.

[0067] (2) Catalyst preparation: 4.7 ml of 4M NaOH solution was poured into a petri dish, followed by 11.72 ml of 0.15 g / ml copper nitrate solution. The mixture was stirred thoroughly to generate Cu(OH)₂. 10 g of the prepared composite Hf-containing support material was added to the resulting mixture. The mixture was stirred magnetically at 200 r / min for 6 h to ensure thorough impregnation. After stirring, the supernatant was filtered off, and the residue was repeatedly washed with deionized water until neutral. Then, it was thoroughly washed with anhydrous ethanol. The residue was then dried in a high-voltage electric field drying device with an electric field strength of 20 kV / cm, and then calcined in a muffle furnace at 400 °C for 2 h to obtain the CuO catalyst supported on the composite Hf-containing support material.

[0068] (3) Application of the catalyst in the selective hydrogenation of acetylene: 0.25 g of this catalyst was applied to the selective hydrogenation of acetylene in a fixed-bed reactor under the following reaction conditions: temperature 120℃, n(HCl):n(H2) = 1:2, and acetylene space velocity 6000 h⁻¹. -1In the initial stage of the reaction, the acetylene conversion rate was 70.2% and the ethylene selectivity was 98.3%; after 1000 hours of reaction, the acetylene conversion rate was 61.1% and the ethylene selectivity was 97.8%.

[0069] Comparative Example 4

[0070] Comparative Example 4 demonstrates, by comparing it with Example 1, that the high-voltage electric field drying technology can significantly improve the catalytic activity and stability of the catalyst in the selective hydrogenation reaction of acetylene.

[0071] (1) Preparation of the carrier: 224.91 g Hf, 14.56 g Si and 23.782 g boron were weighed into a starting mixture and ground in a ball mill for 2 h at a speed of 300 r / min to obtain a well-mixed mixture. The mixture was then dispersed in a ball mill for 30 min under humid conditions with an appropriate amount of ethanol as a dispersant, just enough to cover the mixture. The slurry was then homogenized again by ultrasonication for 60 min at an ultrasonic input power of 50 W and then dried by rotary evaporation. The dried powder mixture was pressed into cylindrical particles (approximately 11 mm in diameter and 20 mm in thickness). The cylindrical particles were then placed in a self-propagating high-temperature synthesizer and heated to 1800 °C for 30 min. The cooled cylindrical particles were then ground in a ball mill for 4 h at a speed of 300 r / min to obtain a composite Hf-containing carrier material.

[0072] (2) Catalyst preparation: 4.7 ml of 4M NaOH solution was poured into a petri dish, followed by 11.72 ml of 0.15 g / ml copper nitrate solution. The mixture was stirred thoroughly to generate Cu(OH)₂. 10 g of the prepared composite Hf-containing support material was added to the resulting mixture. The mixture was stirred magnetically at 200 r / min for 6 h to ensure thorough impregnation. After stirring, the supernatant was filtered off, and the residue was repeatedly washed with deionized water until neutral. Then, it was thoroughly washed with anhydrous ethanol. The residue was then dried in an oven at 120 °C and calcined in a muffle furnace at 400 °C for 1 h to obtain the CuO catalyst supported on the composite Hf-containing support material.

[0073] (3) Application of the catalyst in the selective hydrogenation of acetylene: 0.25 g of this catalyst was applied to the selective hydrogenation of acetylene in a fixed-bed reactor under the following reaction conditions: temperature 120℃, n(HCl):n(H2) = 1:2, and acetylene space velocity 6000 h⁻¹. -1 In the initial stage of the reaction, the acetylene conversion rate was 80.6% and the ethylene selectivity was 99.0%; after 1000 hours of reaction, the acetylene conversion rate was 76.4% and the ethylene selectivity was 98.6%.

[0074] Comparative Example 5

[0075] Comparative Example 5 demonstrates, by comparing it with Example 1, that ultrasonic treatment during secondary grinding can significantly improve the catalytic activity and stability of the catalyst in the selective hydrogenation reaction of acetylene.

[0076] (1) Preparation of the carrier: 224.91 g of Hf, 14.56 g of Si, and 23.782 g of boron were weighed into a starting mixture and ground in a ball mill for 2 hours at a speed of 300 r / min to obtain a well-mixed mixture. The mixture was then dispersed in a ball mill for 30 minutes under humid conditions with an appropriate amount of ethanol as a dispersant, ensuring the ethanol completely covers the mixture. Finally, the mixture was dried by rotary evaporation. The dried powder mixture was pressed into cylindrical particles (approximately 11 mm in diameter and 20 mm in thickness). The cylindrical particles were then placed in a self-propagating high-temperature synthesizer and heated to 1800 °C for 30 minutes. The cooled cylindrical particles were then ground in a ball mill for 4 hours at a speed of 300 r / min to obtain a composite Hf-containing carrier material.

[0077] (2) Catalyst preparation: 4.7 ml of 4M NaOH solution was poured into a petri dish, followed by 11.72 ml of 0.15 g / ml copper nitrate solution. The mixture was stirred thoroughly to generate Cu(OH)₂. 10 g of the prepared composite Hf-containing support material was added to the resulting mixture. The mixture was stirred magnetically at 200 r / min for 6 h to ensure thorough impregnation. After stirring, the supernatant was filtered off, and the residue was repeatedly washed with deionized water until neutral. Then, it was thoroughly washed with anhydrous ethanol. The residue was then dried in a high-voltage electric field drying device with an electric field strength of 20 kV / cm, and then calcined in a muffle furnace at 400 °C for 2 h to obtain the CuO catalyst supported on the composite Hf-containing support material.

[0078] (3) Application of the catalyst in the selective hydrogenation of acetylene: 0.25 g of this catalyst was applied to the selective hydrogenation of acetylene in a fixed-bed reactor under the following reaction conditions: temperature 120℃, n(HCl):n(H2) = 1:2, and acetylene space velocity 6000 h⁻¹. -1 In the initial stage of the reaction, the acetylene conversion rate was 90.4% and the ethylene selectivity was 98.8%; after 1000 hours of reaction, the acetylene conversion rate was 88.15% and the ethylene selectivity was 97.6%.

Claims

1. A method for preparing a CuO catalyst supported on a composite Hf-containing support material, comprising the following steps: Step 1: Grind the initial mixture of Hf, Si and boron in a ball mill to obtain a well-mixed mixture; wherein the molar ratio of Hf to boron is 5.5-6.3:11, and the molar ratio of silicon to boron is 1-3:

11. Step 2: The mixture obtained in Step 1 is dispersed in a ball mill under humid conditions using ethanol as a dispersant. The slurry is then homogenized again using an ultrasonic apparatus and dried by rotary evaporation to obtain a dry powder mixture. Step 3: Dry-press the dried powder mixture into cylindrical particles of a certain size to match the reaction cell of the self-propagating high-temperature synthesizer. Then, put the cylindrical particles into the reaction cell of the self-propagating high-temperature synthesizer and heat them to 1800℃ in the self-propagating high-temperature synthesizer and hold for 10~30 minutes. Step 4: Grind the cooled cylindrical particles in a ball mill to obtain a composite Hf-containing carrier material; Step 5: Pour an appropriate amount of NaOH or KOH solution into the reaction vessel, then add a precursor solution containing copper ions, and stir thoroughly to generate Cu(OH)2; add the composite Hf-containing support material prepared in Step 4 to the resulting mixture, and stir magnetically to ensure thorough impregnation. After stirring, filter off the upper liquid and repeatedly wash the residue with deionized water until neutral, then wash thoroughly with anhydrous ethanol, and then dry the residue using a high-voltage electric field drying technique. Finally, place it in a muffle furnace and calcine it in an air atmosphere to obtain the CuO catalyst supported by the composite Hf-containing support material.

2. The preparation method according to claim 1, characterized in that: In step five, the electric field strength of the high-voltage electric field drying technology is 10~20 kV / cm.

3. The preparation method according to claim 1, characterized in that: In step five, the calcination temperature of the muffle furnace is ≥400℃, and the calcination time is 1~3h.

4. The preparation method according to claim 1, characterized in that: In the CuO catalyst supported by the composite Hf-containing support material, the loading of copper element is 3~6 wt.% based on 100% of the support mass.

5. The CuO catalyst supported on a composite Hf-containing support material prepared by the preparation method according to any one of claims 1-4.

6. The application of the CuO catalyst supported by the composite Hf-containing support material as described in claim 5 in the selective hydrogenation of acetylene to ethylene.

7. The application as described in claim 6, characterized in that: The specific application is as follows: In a fixed-bed reactor, the CuO catalyst supported by the composite Hf-containing support material is loaded, and the raw material gases H2 and C2H2 are introduced. The reaction temperature is controlled at 120~140℃ to obtain ethylene.

8. The application as described in claim 7, characterized in that: The molar ratio of the raw material gases is n(H2):n(C2H2) = 1:1~2:1, and the acetylene volume hourly space velocity is 5000~6000 h⁻¹. -1 .