Expanded graphite worm powder loaded Cu-In-Fe trimetallic catalyst and its preparation and application

Abstract

This invention discloses a Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder, its preparation, and its application. The expanded graphite worm powder-supported Cu-In-Fe trimetallic catalyst is prepared using expanded graphite worm powder as a support through the following method: copper, indium, and iron salts are loaded onto expanded graphite worm powder via wet impregnation to obtain a mixed sample. The mixed sample is then calcined at high temperature in an inert gas environment to obtain a calcined product. The calcined product is then reduced in a hydrogen atmosphere to obtain the expanded graphite worm powder-supported Cu-In-Fe trimetallic catalyst. This invention provides the application of the expanded graphite worm powder-supported Cu-In-Fe trimetallic catalyst in the acetylene semi-hydrogenation reaction. The catalyst provided by this invention has the characteristics of simple preparation, good stability, high conversion rate, high selectivity, and relatively low reaction temperature.

Description

Technical Field

[0001] This invention belongs to the field of acetylene hydrogenation catalysts, specifically relating to a Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder, its preparation, and its application in the acetylene semi-hydrogenation reaction. Technical Background

[0002] Ethylene is one of the most important chemicals in the petrochemical industry, typically obtained through the cracking of petroleum hydrocarbons, with trace amounts of acetylene as a byproduct. Trace amounts of acetylene can poison ethylene polymerization catalysts and reduce the quality of polyethylene. The semi-hydrogenation of acetylene in an ethylene-rich gas stream is a critical step in the industrial production of polyethylene. An ideal catalyst should be able to selectively convert acetylene to ethylene while preventing further hydrogenation of ethylene to ethane.

[0003] Cu-based catalysts have attracted widespread attention due to their high ethylene selectivity resulting from strong acetylene adsorption and weak ethylene adsorption. However, their weak hydrogen dissociation ability, low catalytic activity, and susceptibility to CC polymerization leading to green oil formation cause catalyst deactivation. Modifying the geometry or electronic structure of Cu-based catalysts and controlling the size, morphology, and distribution of copper nanoparticles by utilizing their interaction with promoters and supports is key to improving the catalytic hydrogenation activity, selectivity, and durability of Cu-based catalysts. Although using traditional metal oxides (such as Al₂O₃ and Ti₂O₃) as supports can improve the dispersibility of Cu nanoparticles, synthesizing highly dispersed nanoparticles with uniform size using conventional methods remains challenging.

[0004] Expanded graphite worm powder (EG) is a loose, porous, worm-like material obtained from natural graphite flakes through intercalation, washing, drying, and high-temperature expansion. As a novel functional carbon material, EG possesses not only the excellent properties of natural graphite, such as resistance to cold and heat, corrosion resistance, and self-lubrication, but also unique characteristics not found in natural graphite, including softness, compression resilience, adsorption, environmental compatibility, biocompatibility, and radiation resistance. Expanded graphite can expand 150 to 300 times its original volume instantly upon exposure to high temperatures, transforming from a sheet-like structure into a worm-like form. This results in a loose, porous, and flexible structure, increased surface area, enhanced surface energy, and stronger adsorption of graphite flakes. The worm-like graphite particles can also self-interlock, further increasing its softness, resilience, and plasticity. Therefore, expanded graphite worm powder has particularly wide applications in petroleum, chemical, nuclear energy, power, and pharmaceutical industries. With the advancement of science and technology and the development of high technology, expanded graphite, a new engineering material, is gradually replacing certain metallic and organic synthetic materials in high-tech fields such as high speed, corrosion resistance, wear resistance, and energy saving.

[0005] Therefore, it is necessary to develop a method for preparing Cu-based trimetallic catalysts supported on expanded graphite worm powder, to adjust the geometry and electronic structure of Cu nanoparticles and generate a synergistic effect, thereby improving the catalyst's acetylene semi-hydrogenation catalytic performance.

[0006] Based on the above background, this invention proposes a Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder. Summary of the Invention

[0007] The purpose of this invention is to provide a Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder, its preparation method, and its application in the acetylene semi-hydrogenation reaction. This catalyst overcomes the shortcomings of copper-based catalysts in acetylene semi-hydrogenation, such as low catalytic activity and poor stability, and has the characteristics of simple preparation, good stability, high conversion rate, high selectivity, and relatively low reaction temperature.

[0008] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows:

[0009] In a first aspect, the present invention provides a Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder (EG). The catalyst is prepared by using expanded graphite worm powder as a support through the following method: copper salt, indium salt, and iron salt are loaded onto expanded graphite worm powder by wet impregnation to obtain a mixed sample; the mixed sample is then placed in an inert gas environment and calcined at high temperature to obtain a calcined product; the calcined product is then reduced in a hydrogen atmosphere to obtain the expanded graphite worm powder supported Cu-In-Fe trimetallic catalyst.

[0010] The feeding ratio of copper salt, indium salt, iron salt, and expanded graphite worm powder should be such that the theoretical loading of copper in the expanded graphite worm powder-supported Cu-In-Fe trimetallic catalyst is 1%-10%, the theoretical loading of indium is 0.1%-5%, and the theoretical loading of iron is 0.1%-2.5%. The theoretical loading is calculated as the percentage of the mass of copper, indium, and iron elements contained in each of the copper salt, indium salt, and iron salt relative to the mass of the expanded graphite worm powder.

[0011] Preferably, the theoretical loading of copper is 1%-5%, the theoretical loading of indium is 0.5%-2.5%, and the theoretical loading of iron is 0.5%-2%.

[0012] Preferably, the calcination temperature is 150-1200℃, more preferably 250-1000℃, and even more preferably 350-700℃; the calcination time is 1-8h, more preferably 2-6h.

[0013] Preferably, the reduction temperature is 200-600℃, more preferably 350-450℃; the reduction time is 1-4h.

[0014] In a second aspect, the present invention provides a method for preparing the Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder as described in the first aspect, comprising the following steps:

[0015] (1) Weigh out copper salt, indium salt and iron salt and dissolve them in deionized water. Stir thoroughly at room temperature to obtain a mixed solution. Add expanded graphite worm powder (EG) to the above mixed solution and stir the mixture at room temperature for 8-12 hours. Dry the mixture to obtain mixed sample powder.

[0016] (2) The mixed sample powder obtained in step (1) is placed in an inert gas environment and calcined at high temperature to obtain the calcined product;

[0017] (3) The calcined product obtained in step (2) is reduced in a hydrogen atmosphere to obtain Cu-In-Fe trimetallic catalyst (Cu-In-Fe / EG) supported on expanded graphite worm powder.

[0018] Preferably, the copper salt in step (1) is selected from one or more of anhydrous or water-containing copper nitrate, copper sulfate, copper chloride, copper bromide, and copper acetate.

[0019] Preferably, the indium salt in step (1) is selected from one or more of indium chloride, indium sulfate, indium nitrate, indium perchlorate, and indium cyclohexane.

[0020] Preferably, the iron salt mentioned in step (1) is selected from one or more of anhydrous and water-containing iron hydroxide, iron sulfate, iron sulfate, iron chloride, iron nitrate, and iron phthalocyanine.

[0021] Preferably, the drying temperature in step (1) is 60-120℃, more preferably 80-110℃; and the drying time is 8-12h.

[0022] Preferably, the inert gas in step (2) is one of nitrogen, argon, or helium.

[0023] Preferably, the calcination temperature in step (2) is 150-1200℃, more preferably 250-1000℃, and even more preferably 350-700℃; the calcination time is 1-8h, more preferably 2-6h.

[0024] Preferably, in step (3), the reduction temperature is 200-600℃, more preferably 350-450℃; and the reduction time is 1-4h.

[0025] The expanded graphite worm powder of this invention can be prepared by methods reported in existing literature. Specifically, this invention provides a method for preparing expanded graphite worm powder, comprising the following steps:

[0026] (a) Add graphite and an appropriate amount of concentrated sulfuric acid to a beaker, mix, stir at room temperature for ≥2 hours to obtain a mixture, add potassium persulfate to the mixture, stir evenly, and immediately transfer to a water bath to obtain acidic expanded graphite; wherein, by mass, the ratio of graphite:potassium persulfate:concentrated sulfuric acid is 1:5-10:40-100, preferably 1:5-10:45-55;

[0027] (b) The acidic expanded graphite obtained in step (1) is filtered and washed in a vacuum until neutral, and then dried to obtain expanded graphite worm powder (EG). The preparation method of this expanded graphite worm powder is relatively mild.

[0028] Preferably, in step (a), the graphite is selected from one or more of dense crystalline graphite, flake graphite, and cryptocrystalline graphite.

[0029] Preferably, the water bath temperature in step (a) is 40-120°C, more preferably 60-100°C, and the water bath time is 1-20 min.

[0030] Preferably, the drying temperature in step (b) is 40-100℃ and the drying time is 3-8h.

[0031] Thirdly, the present invention provides an application of the expanded graphite worm powder-supported Cu-In-Fe trimetallic catalyst according to the first aspect in the acetylene semi-hydrogenation reaction.

[0032] Preferably, the acetylene semi-hydrogenation reaction is carried out as follows: in a fixed-bed reactor filled with expanded graphite worm powder supported on a Cu-In-Fe trimetallic catalyst, a feed gas containing acetylene and hydrogen is introduced to convert acetylene into ethylene.

[0033] As a further preferred option, the reaction conditions for the semi-hydrogenation of acetylene are: a reaction temperature of 80–250°C, more preferably 150–200°C, and even more preferably 150–180°C; and a reaction pressure of 0.1 MPa.

[0034] In a specific embodiment of the present invention, the composition of the feed gas containing acetylene and hydrogen is: acetylene, hydrogen, ethylene, and the balance nitrogen, with a feed space velocity of 1000–20000 h⁻¹. -1 .

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] 1. This invention utilizes expanded graphite worm powder to support a Cu-In-Fe trimetallic catalyst, which improves the structural stability of copper, reduces the loss of active components, and enhances the stability of the catalyst.

[0037] 2. The expanded graphite worm powder-supported Cu-In-Fe trimetallic catalyst described in this invention exhibits better catalytic activity compared to other copper-based catalysts;

[0038] 3. In this invention, expanded graphite worm powder loaded with Cu-In-Fe trimetallic catalyst is used for the acetylene semi-hydrogenation reaction. The high specific surface area of ​​expanded graphite worm powder is conducive to the dispersion of metal elements and the adsorption of reactants and the desorption of products, thereby improving the conversion rate of acetylene and the selectivity of ethylene.

[0039] 4. Compared with precious metal catalysts, the expanded graphite worm powder supported Cu-In-Fe trimetallic catalyst of the present invention is relatively inexpensive and suitable for industrial application.

[0040] In summary, the method for preparing Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder described in this invention significantly improves the stability, activity, and selectivity of the catalyst compared to traditional copper-based catalysts, and has excellent application prospects. Detailed Implementation

[0041] The present invention will be illustrated below with specific examples. 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-described invention.

[0042] Unless otherwise specified in the embodiments of this invention, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained through conventional technical means or commercially available.

[0043] This invention uses an online gas chromatograph to analyze the hydrogenation products of acetylene and determines the conversion rate of acetylene and its selectivity for ethylene by area normalization.

[0044] Example 1

[0045] 1) Add 10g of graphite and 500g of concentrated sulfuric acid to a beaker, mix, and stir at room temperature for 10 hours to obtain a mixture. Add 70g of potassium persulfate to the mixture, stir evenly, and immediately transfer to an 80℃ water bath for 5 minutes to obtain acidic expanded graphite. Filter the obtained acidic expanded graphite under vacuum, wash until neutral, and dry at 60℃ for 5 hours to obtain expanded graphite worm powder (EG).

[0046] 2) Weigh 0.21g of anhydrous copper chloride, 0.1g of indium trichloride, and 0.145g of ferric chloride and dissolve them in deionized water. Stir thoroughly at room temperature to obtain a mixed solution. Add 5g of expanded graphitic worm powder to the above mixed solution and stir the mixture at room temperature for 10 hours. Dry the mixture at 100℃ for 10 hours to obtain a mixed sample powder. Calcinate the obtained mixed sample powder at 600℃ for 4 hours in an argon atmosphere to obtain the calcined product.

[0047] 3) Place 0.3g of calcined product in a fixed-bed reactor. Before the reaction, introduce pure H2 and reduce it at 400℃ for 2h. The reducing gas flow rate is 50mL / min to obtain Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder (Cu-In-Fe / EG).

[0048] 4) After reduction, an acetylene mixture is introduced at a rate of 50 mL / min. The volume concentration composition of the acetylene mixture is: 0.33% acetylene, 3.3% hydrogen, 33% ethylene, with the balance being nitrogen, totaling 100%. The mixture is then introduced at a space velocity of 10000 h⁻¹. -1 The hydrogenation reaction was carried out at a pressure of 0.1 MPa and a temperature of 180 °C. The peak areas of ethane, ethylene, acetylene, and C4 were detected online using gas chromatography, and the conversion rate of acetylene and the selectivity of ethylene were determined by area normalization.

[0049] Chromatographic data showed that when the reaction reached a stable state, the acetylene conversion rate was 99.8% and the ethylene selectivity was 98.8%. After 350 hours of reaction, the acetylene conversion rate was 98.9% and the ethylene selectivity was 97.1%.

[0050] Comparative Example 1

[0051] 1) Weigh 0.21g of anhydrous copper chloride, 0.1g of indium trichloride, and 0.145g of ferric chloride and dissolve them in deionized water. Stir thoroughly at room temperature to obtain a mixed solution. Add 5g of γ-alumina (325 mesh) to the above mixed solution and stir the mixture at room temperature for 10h. Dry the mixture at 100℃ for 10h to obtain a mixed sample powder. Calcinate the obtained mixed sample powder at 600℃ for 4h in an argon atmosphere to obtain the calcined product.

[0052] 2) Place 0.3g of calcined product in a fixed-bed reactor. Before the reaction, reduce it at 400℃ for 2h by passing pure H2 through it. The reducing gas flow rate is 50mL / min to obtain γ-alumina supported Cu-In-Fe trimetallic catalyst (Cu-In-Fe / γ-Al2O3).

[0053] 4) After reduction, an acetylene mixture is introduced at a rate of 50 mL / min. The volume concentration composition of the acetylene mixture is: 0.33% acetylene, 3.3% hydrogen, 33% ethylene, with the balance being nitrogen, totaling 100%. The mixture is then introduced at a space velocity of 10000 h⁻¹.-1 The hydrogenation reaction was carried out at a pressure of 0.1 MPa and a temperature of 180 °C. The peak areas of ethane, ethylene, acetylene, and C4 were detected online by gas chromatography, and the conversion rate of acetylene and the selectivity of ethylene were determined by the area normalization method.

[0054] Chromatographic data showed that when the reaction reached a stable state, the acetylene conversion rate was 95.6% and the ethylene selectivity was 90.8%. After 150 hours of reaction, the acetylene conversion rate was 91.2% and the ethylene selectivity was 67.1%.

[0055] Comparative Example 2

[0056] 1) Weigh 0.21g of anhydrous copper chloride, 0.1g of indium trichloride, and 0.145g of ferric chloride and dissolve them in deionized water. Stir thoroughly at room temperature to obtain a mixed solution. Add 5g of titanium dioxide (325 mesh) to the above mixed solution and stir the mixture at room temperature for 10h. Dry the mixture at 100℃ for 10h to obtain a mixed sample powder. Calcinate the obtained mixed sample powder at 600℃ for 4h in an argon atmosphere to obtain the calcined product.

[0057] 2) Place 0.3g of calcined product in a fixed-bed reactor. Before the reaction, reduce it at 400℃ for 2h by passing pure H2 through it. The reducing gas flow rate is 50mL / min to obtain γ-alumina supported Cu-In-Fe trimetallic catalyst (Cu-In-Fe / γ-Al2O3).

[0058] 4) After reduction, an acetylene mixture is introduced at a rate of 50 mL / min. The volume concentration composition of the acetylene mixture is: 0.33% acetylene, 3.3% hydrogen, 33% ethylene, with the balance being nitrogen, totaling 100%. The mixture is then introduced at a space velocity of 10000 h⁻¹. -1 The hydrogenation reaction was carried out at a pressure of 0.1 MPa and a temperature of 180 °C. The peak areas of ethane, ethylene, acetylene, and C4 were detected online by gas chromatography, and the conversion rate of acetylene and the selectivity of ethylene were determined by the area normalization method.

[0059] Chromatographic data showed that when the reaction reached a stable state, the acetylene conversion rate was 94.9% and the ethylene selectivity was 91.1%. After 150 hours of reaction, the acetylene conversion rate was 90.2% and the ethylene selectivity was 69.7%.

[0060] Through Example 1 and Comparative Examples 1-2, it can be seen that the Cu-In-Fe trimetallic catalyst supported by expanded graphite worm powder is superior to the catalysts supported by γ-alumina and titanium dioxide.

[0061] Example 2

[0062] 1) Add 10g of graphite and 500g of concentrated sulfuric acid to a beaker, mix, and stir at room temperature for 10 hours to obtain a mixture. Add 70g of potassium persulfate to the mixture, stir evenly, and immediately transfer to an 80℃ water bath for 5 minutes to obtain acidic expanded graphite. Filter the obtained acidic expanded graphite under vacuum, wash until neutral, and dry at 60℃ for 5 hours to obtain expanded graphite worm powder (EG).

[0063] 2) Weigh 0.295g of anhydrous copper nitrate, 0.131g of indium nitrate, and 0.217g of ferric nitrate and dissolve them in deionized water. Stir thoroughly at room temperature to obtain a mixed solution. Add 5g of expanded graphite worm powder to the above mixed solution and stir the mixture at room temperature for 10h. Dry the mixture at 90℃ for 10h to obtain a mixed sample powder. Calcinate the obtained mixed sample powder at 500℃ for 4h in an argon atmosphere to obtain the calcined product.

[0064] 3) Place 0.3g of calcined product in a fixed-bed reactor. Before the reaction, introduce pure H2 and reduce it at 400℃ for 2h. The reducing gas flow rate is 50mL / min to obtain Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder (Cu-In-Fe / EG).

[0065] 4) After reduction, an acetylene mixture is introduced at a rate of 50 mL / min. The volume concentration of the acetylene mixture is: 0.33% acetylene, 6.6% hydrogen, 33% ethylene, and the balance nitrogen, totaling 100%. The mixture is then introduced at a space velocity of 10000 h⁻¹. -1 The hydrogenation reaction was carried out at a pressure of 0.1 MPa and a temperature of 150 °C. The peak areas of ethane, ethylene, acetylene, and C4 were detected online by gas chromatography, and the conversion rate of acetylene and the selectivity of ethylene were determined by the area normalization method.

[0066] Chromatographic data showed that when the reaction reached a stable state, the acetylene conversion rate was 99.9% and the ethylene selectivity was 99.1%. After 300 hours of reaction, the acetylene conversion rate was 98.8% and the ethylene selectivity was 98.2%.

[0067] Comparative Example 3

[0068] 1) Add 10g of graphite and 100g of concentrated sulfuric acid to a beaker, mix, and stir at room temperature for 10 hours to obtain a mixture. Add 70g of potassium persulfate to the mixture, stir evenly, and immediately transfer to an 80℃ water bath for 5 minutes to obtain acidic expanded graphite. Filter the obtained acidic expanded graphite under vacuum, wash until neutral, and dry at 60℃ for 5 hours to obtain expanded graphite worm powder (EG).

[0069] 2) Weigh 0.295g of anhydrous copper nitrate, 0.131g of indium nitrate, and 0.217g of ferric nitrate and dissolve them in deionized water. Stir thoroughly at room temperature to obtain a mixed solution. Add 5g of expanded graphite worm powder to the above mixed solution and stir the mixture at room temperature for 10h. Dry the mixture at 90℃ for 10h to obtain a mixed sample powder. Calcinate the obtained mixed sample powder at 500℃ for 4h in an argon atmosphere to obtain the calcined product.

[0070] 3) Place 0.3g of calcined product in a fixed-bed reactor. Before the reaction, introduce pure H2 and reduce it at 400℃ for 2h. The reducing gas flow rate is 50mL / min to obtain Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder (Cu-In-Fe / EG).

[0071] 4) After reduction, an acetylene mixture is introduced at a rate of 50 mL / min. The volume concentration of the acetylene mixture is: 0.33% acetylene, 6.6% hydrogen, 33% ethylene, and the balance nitrogen, totaling 100%. The mixture is then introduced at a space velocity of 10000 h⁻¹. -1 The hydrogenation reaction was carried out at a pressure of 0.1 MPa and a temperature of 150 °C. The peak areas of ethane, ethylene, acetylene, and C4 were detected online by gas chromatography, and the conversion rate of acetylene and the selectivity of ethylene were determined by the area normalization method.

[0072] Chromatographic data showed that when the reaction reached a stable state, the acetylene conversion rate was 90.3% and the ethylene selectivity was 88.9%. After 100 hours of reaction, the acetylene conversion rate was 73.8% and the ethylene selectivity was 70.9%.

[0073] Through Example 2 and Comparative Example 3, it can be seen that the ratio of graphite to concentrated sulfuric acid affects the performance of the expanded graphite worm powder as a carrier, thereby affecting the performance of the catalyst described in this invention.

[0074] Example 3

[0075] 1) Add 10g of graphite and 500g of concentrated sulfuric acid to a beaker, mix, and stir at room temperature for 10 hours to obtain a mixture. Add 70g of potassium persulfate to the mixture, stir evenly, and immediately transfer to an 80℃ water bath for 5 minutes to obtain acidic expanded graphite. Filter the obtained acidic expanded graphite under vacuum, wash until neutral, and dry at 80℃ for 5 hours to obtain expanded graphite worm powder (EG).

[0076] 2) Weigh 0.251 g of anhydrous copper sulfate, 0.113 g of indium sulfate, and 0.179 g of ferric sulfate and dissolve them in deionized water. Stir thoroughly at room temperature to obtain a mixed solution. Add 5 g of expanded graphite worm powder to the above mixed solution and stir the mixture at room temperature for 8 h. Dry the mixture at 90 °C for 10 h to obtain a mixed sample powder. Calcinate the obtained mixed sample powder at 400 °C for 4 h in an argon atmosphere to obtain the calcined product.

[0077] 3) Place 0.3g of calcined product in a fixed-bed reactor. Before the reaction, introduce pure H2 and reduce it at 400℃ for 2h. The reducing gas flow rate is 50mL / min to obtain Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder (Cu-In-Fe / EG).

[0078] 4) After reduction, an acetylene mixture is introduced at a rate of 50 mL / min. The volume concentration composition of the acetylene mixture is: 0.33% acetylene, 3.3% hydrogen, 33% ethylene, with the balance being nitrogen, totaling 100%. The mixture is then introduced at a space velocity of 10000 h⁻¹. -1 The hydrogenation reaction was carried out at a pressure of 0.1 MPa and a temperature of 160 °C. The peak areas of ethane, ethylene, acetylene, and C4 were detected online by gas chromatography, and the conversion rate of acetylene and the selectivity of ethylene were determined by the area normalization method.

[0079] Chromatographic data showed that when the reaction reached a stable state, the acetylene conversion rate was 99.5% and the ethylene selectivity was 98.9%. After 400 hours of reaction, the acetylene conversion rate was 98.1% and the ethylene selectivity was 97.1%.

[0080] Comparative Example 4

[0081] 1) Add 10g of graphite and 500g of concentrated sulfuric acid to a beaker, mix, and stir at room temperature for 10 hours to obtain a mixture. Add 70g of potassium persulfate to the mixture, stir evenly, and immediately transfer to an 80℃ water bath for 5 minutes to obtain acidic expanded graphite. Filter the obtained acidic expanded graphite under vacuum, wash until neutral, and dry at 80℃ for 5 hours to obtain expanded graphite worm powder (EG).

[0082] 2) Weigh 0.251 g of anhydrous copper sulfate and dissolve it in deionized water. Stir thoroughly at room temperature to obtain a mixed solution. Add 5 g of expanded graphite worm powder to the above mixed solution and stir the mixture at room temperature for 8 h. Dry at 90 °C for 10 h to obtain a mixed sample powder. Place the obtained mixed sample powder in an argon atmosphere and calcine at 400 °C for 4 h to obtain the calcined product.

[0083] 3) Place 0.3g of calcined product in a fixed-bed reactor. Before the reaction, reduce it at 400℃ for 2h by passing pure H2 through it. The reducing gas flow rate is 50mL / min to obtain Cu catalyst supported on expanded graphite worm powder (Cu / EG).

[0084] 4) After reduction, an acetylene mixture is introduced at a rate of 50 mL / min. The volume concentration composition of the acetylene mixture is: 0.33% acetylene, 3.3% hydrogen, 33% ethylene, with the balance being nitrogen, totaling 100%. The mixture is then introduced at a space velocity of 10000 h⁻¹. -1The hydrogenation reaction was carried out at a pressure of 0.1 MPa and a temperature of 160 °C. The peak areas of ethane, ethylene, acetylene, and C4 were detected online by gas chromatography, and the conversion rate of acetylene and the selectivity of ethylene were determined by the area normalization method.

[0085] Chromatographic data showed that when the reaction reached a stable state, the acetylene conversion rate was 77.5% and the ethylene selectivity was 52.3%. After 50 hours of reaction, the acetylene conversion rate was 61.1% and the ethylene selectivity was 47.1%.

[0086] Comparative Example 5

[0087] 1) Add 10g of graphite and 500g of concentrated sulfuric acid to a beaker, mix, and stir at room temperature for 10 hours to obtain a mixture. Add 70g of potassium persulfate to the mixture, stir evenly, and immediately transfer to an 80℃ water bath for 5 minutes to obtain acidic expanded graphite. Filter the obtained acidic expanded graphite under vacuum, wash until neutral, and dry at 80℃ for 5 hours to obtain expanded graphite worm powder (EG).

[0088] 2) Weigh 0.113 g of indium sulfate and dissolve it in deionized water. Stir thoroughly at room temperature to obtain a mixed solution. Add 5 g of expanded graphite worm powder to the above mixed solution and stir the mixture at room temperature for 8 h. Dry at 90 °C for 10 h to obtain a mixed sample powder. Place the obtained mixed sample powder in an argon atmosphere and calcine at 400 °C for 4 h to obtain the calcined product.

[0089] 3) Place 0.3g of calcined product in a fixed-bed reactor. Before the reaction, reduce it at 400℃ for 2h by passing pure H2 through it. The reducing gas flow rate is 50mL / min to obtain expanded graphite worm powder supported In catalyst (In / EG).

[0090] 4) After reduction, an acetylene mixture is introduced at a rate of 50 mL / min. The volume concentration composition of the acetylene mixture is: 0.33% acetylene, 3.3% hydrogen, 33% ethylene, with the balance being nitrogen, totaling 100%. The mixture is then introduced at a space velocity of 10000 h⁻¹. -1 The hydrogenation reaction was carried out at a pressure of 0.1 MPa and a temperature of 160 °C. The peak areas of ethane, ethylene, acetylene, and C4 were detected online by gas chromatography, and the conversion rate of acetylene and the selectivity of ethylene were determined by the area normalization method.

[0091] Chromatographic data showed that when the reaction reached a stable state, the acetylene conversion rate was 27.5% and the ethylene selectivity was 22.3%. After 15 hours of reaction, the acetylene conversion rate was 22.1% and the ethylene selectivity was 17.5%.

[0092] Comparative Example 6

[0093] 1) Add 10g of graphite and 500g of concentrated sulfuric acid to a beaker, mix, and stir at room temperature for 10 hours to obtain a mixture. Add 70g of potassium persulfate to the mixture, stir evenly, and immediately transfer to an 80℃ water bath for 5 minutes to obtain acidic expanded graphite. Filter the obtained acidic expanded graphite under vacuum, wash until neutral, and dry at 80℃ for 5 hours to obtain expanded graphite worm powder (EG).

[0094] 2) Weigh 0.179 g of ferric sulfate and dissolve it in deionized water, stirring thoroughly at room temperature to obtain a mixed solution. Add 5 g of expanded graphite worm powder to the above mixed solution, and stir the mixture at room temperature for 8 h, then dry it at 90 °C for 10 h to obtain a mixed sample powder. Place the obtained mixed sample powder in an argon atmosphere and calcine at 400 °C for 4 h to obtain the calcined product.

[0095] 3) Place 0.3g of calcined product in a fixed-bed reactor. Before the reaction, reduce it at 400℃ for 2h by passing pure H2 through it. The reducing gas flow rate is 50mL / min to obtain expanded graphite worm powder supported Fe catalyst (Fe / EG).

[0096] 4) After reduction, an acetylene mixture is introduced at a rate of 50 mL / min. The volume concentration composition of the acetylene mixture is: 0.33% acetylene, 3.3% hydrogen, 33% ethylene, with the balance being nitrogen, totaling 100%. The mixture is then introduced at a space velocity of 10000 h⁻¹. -1 The hydrogenation reaction was carried out at a pressure of 0.1 MPa and a temperature of 160 °C. The peak areas of ethane, ethylene, acetylene, and C4 were detected online by gas chromatography, and the conversion rate of acetylene and the selectivity of ethylene were determined by the area normalization method.

[0097] Chromatographic data showed that when the reaction reached a stable state, the acetylene conversion rate was 19.5% and the ethylene selectivity was 34.3%. After 15 hours of reaction, the acetylene conversion rate was 11.6% and the ethylene selectivity was 26.5%.

[0098] Through Example 3 and Comparative Examples 4-6, it can be seen that the Cu-In-Fe trimetallic catalyst described in this invention is indeed superior to Cu, In, and Fe single-metal catalysts.

Claims

1. A Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder, characterized in that: The catalyst is prepared using expanded graphite worm powder as a carrier by the following method: copper salt, indium salt and iron salt are loaded onto expanded graphite worm powder by wet impregnation to obtain a mixed sample, and then the mixed sample is placed in an inert gas environment for high-temperature calcination to obtain a calcined product; then the obtained calcined product is reduced in a hydrogen atmosphere to obtain a Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder. The expanded graphite worm powder is prepared by a method comprising the following steps: (a) Add graphite and an appropriate amount of concentrated sulfuric acid to a beaker, mix, stir at room temperature for ≥2 hours to obtain a mixture, add potassium persulfate to the mixture, stir evenly, and immediately transfer to a water bath to obtain acidic expanded graphite; wherein, by mass, the ratio of graphite:potassium persulfate:concentrated sulfuric acid is 1:5-10:40-100. (b) The acidic expanded graphite obtained in step (a) is filtered and washed in a vacuum until neutral, and then dried to obtain expanded graphite worm powder; The feeding ratio of copper salt, indium salt, iron salt, and expanded graphite worm powder should be such that the theoretical loading of copper in the expanded graphite worm powder-supported Cu-In-Fe trimetallic catalyst is 1%-10%, the theoretical loading of indium is 0.1%-5%, and the theoretical loading of iron is 0.1%-2.5%. The theoretical loading is calculated as the percentage of the mass of copper, indium, and iron elements contained in each of the copper salt, indium salt, and iron salt relative to the mass of the expanded graphite worm powder.

2. The Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder as described in claim 1, characterized in that: The theoretical loading of copper is 1%-5%, that of indium is 0.5%-2.5%, and that of iron is 0.5%-2%.

3. The Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder as described in claim 1, characterized in that: The calcination temperature is 150-1200℃; the calcination time is 1-8h.

4. The Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder as described in claim 3, characterized in that: The calcination temperature is 250-1000℃; the calcination time is 2-6h.

5. The Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder as described in claim 4, characterized in that: The calcination temperature is 350-700℃.

6. The Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder as described in claim 1, characterized in that: The reduction temperature is 200-600℃; the reduction time is 1-4 h.

7. The Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder as described in claim 6, characterized in that: The reduction temperature is 350-450℃.

8. The Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder as described in claim 1, characterized in that: In step (a), the ratio of graphite:potassium persulfate:concentrated sulfuric acid is 1:5-10:45-55 by mass.

9. A method for preparing a Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder as described in any one of claims 1-8, characterized in that: The preparation method includes the following steps: (1) Weigh out copper salt, indium salt and iron salt and dissolve them in deionized water. Stir thoroughly at room temperature to obtain a mixed solution. Add expanded graphite worm powder to the above mixed solution and stir the mixture at room temperature for 8-12 hours. Dry the mixture to obtain mixed sample powder. (2) The mixed sample powder obtained in step (1) is placed in an inert gas environment and calcined at high temperature to obtain the calcined product; (3) The calcined product obtained in step (2) is reduced in a hydrogen atmosphere to obtain a Cu-In-Fe trimetallic catalyst supported on expanded graphite worm powder.

10. The preparation method according to claim 9, characterized in that: The water bath temperature in step (a) is 40-120℃ and the water bath time is 1-20min.

11. The preparation method according to claim 10, characterized in that: The water bath temperature in step (a) is 60-100℃.

12. The application of the expanded graphite worm powder-supported Cu-In-Fe trimetallic catalyst as described in any one of claims 1-8 in the acetylene semi-hydrogenation reaction.

13. The application as described in claim 12, characterized in that: The acetylene semi-hydrogenation reaction is carried out as follows: In a fixed-bed reactor filled with expanded graphite worm powder supported on a Cu-In-Fe trimetallic catalyst, a feed gas containing acetylene and hydrogen is introduced to convert acetylene into ethylene.

14. The application as described in claim 13, characterized in that: The reaction conditions for the semi-hydrogenation of acetylene are: reaction temperature 80~250℃, reaction pressure 0.1MPa.