A supported nickel-based carbide acetylene selective hydrogenation catalyst, its preparation method and application

Abstract

The present application relates to the technical field of supported metal nanoparticle catalysts, in particular to a supported nickel-based carbide acetylene selective hydrogenation catalyst, a preparation method and application thereof. The catalyst is formed by supporting a bimetallic carbide active component on a nanometer gallium oxide carrier, the bimetallic carbide is Ni3GaC 0.7 , and the loading amount of Ni in the catalyst is 1-40 wt.%. A nickel salt is loaded on a nanometer gallium oxide material by an impregnation method, then a NiO / Ga2O3 catalyst is obtained by calcining in air; then the catalyst is treated by heating in a mixed gas of carbon dioxide and hydrogen, and a supported Ni3GaC 0.7 / Ga2O3 catalyst is obtained. The acetylene selective hydrogenation reaction performance test results show that the Ni3GaC 0.7 / Ga2O3 catalyst exhibits excellent selectivity (about 85%) in the hydrogenation reaction, and long-term performance test also shows that the supported catalyst has good stability.

Description

Technical Field

[0001] This invention relates to the field of supported metal nanoparticle catalyst technology, specifically to a supported nickel-based carbide acetylene selective hydrogenation catalyst, its preparation method, and its application. Background Technology

[0002] Ethylene is the world's largest-produced petrochemical product and an important chemical intermediate in the production industry, used to produce polyethylene, ethylbenzene, ethylene oxide, and dichloroethane, among others. Ethylene is primarily produced by naphtha cracking, containing approximately 1% acetylene. To prevent acetylene poisoning of the catalyst in subsequent ethylene polymerization reactions, selective hydrogenation of the acetylene in ethylene is necessary to reduce its concentration. Selective hydrogenation to remove acetylene using supported palladium-based catalysts is a widely adopted method in current industrial production, but palladium-based catalysts suffer from high costs. Transition metal nickel offers advantages such as low cost and high hydrogenation activity, but it is prone to over-hydrogenation in the hydrogenation reactions of acetylene and butadiene, leading to reduced selectivity and loss of mono-olefin feedstocks. Furthermore, carbon deposition on the nickel surface during the reaction can cause catalyst deactivation. To improve its performance, nickel catalysts typically require modification. The main methods include: introducing a second metal component to alter the electronic and geometric structure of the nickel catalyst; and controlling the formation of isolated nickel active sites through supports or preparation methods. These studies have improved the selective hydrogenation performance of nickel-based catalysts, but some problems still exist, such as complex catalyst preparation methods, poor reaction stability, and poor ethylene selectivity. Summary of the Invention

[0003] The purpose of this invention is to provide a supported nickel-based carbide acetylene selective hydrogenation catalyst, its preparation method, and its application. Supported Ni3GaC catalysts are prepared using non-noble metal nickel. 0.7 The / Ga2O3 catalyst has replaced the palladium-based catalyst, which not only greatly reduces the cost, but also shows that the catalyst structure exhibits better selectivity and stability in the selective hydrogenation reaction of acetylene.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A supported nickel-based carbide acetylene selective hydrogenation catalyst is disclosed. The catalyst is formed by supporting a bimetallic carbide active component on a nano-gallium oxide support, wherein the bimetallic carbide is Ni3GaC. 0.7 .

[0006] The catalyst has a Ni loading of 1–40 wt.%.

[0007] The gallium oxide nanorods are gallium oxide nanorods.

[0008] The bimetallic carbide Ni3GaC0.7 In this composition, the atomic ratio of Ni to C is 3:0.7.

[0009] The catalyst was prepared by first loading nickel salt onto gallium oxide nanomaterials via impregnation, followed by calcination in air to obtain a NiO / Ga2O3 catalyst; then, it was heated in a mixture of carbon dioxide and hydrogen to obtain a supported Ni3GaC catalyst. 0.7 / Ga2O3 catalyst, which is the supported nickel-based carbide acetylene selective hydrogenation catalyst.

[0010] The catalyst preparation method specifically includes the following steps:

[0011] (1) Dissolve nickel salt in solvent, then add gallium oxide nanomaterial, and ultrasonically stir for 1 to 3 hours to ensure uniform dispersion. After removing the solvent by rotary evaporator, nickel salt gallium oxide nanocomposite material is obtained, with nickel salt loaded on gallium oxide nanomaterial. The obtained nickel salt gallium oxide nanocomposite material is placed in an oven for drying at a temperature of 50 to 200°C for 1 to 5 hours.

[0012] (2) The nickel salt nano-gallium oxide composite material treated in step (1) is calcined in air to obtain NiO / Ga2O3 catalyst;

[0013] (3) The NiO / Ga2O3 catalyst obtained in step (2) is heat-treated in a mixed atmosphere of hydrogen and carbon dioxide, and then cooled to room temperature to obtain Ni3GaC. 0.7 / Ga2O3 supported catalyst.

[0014] In step (1), the gallium oxide nanorods are gallium oxide nanorods; the nickel salt is selected from one or more of nickel acetate, nickel chloride, nickel nitrate, nickel carbonate, nickel sulfate and nickel acetylacetonate; the solvent is water, ethanol or methanol.

[0015] In step (2), when air treatment is used, the air flow rate is 20-300 mL / min, the treatment temperature is 300-500℃, and the treatment time is 1-5 hours.

[0016] In step (3), when using a mixture of hydrogen and carbon dioxide for heat treatment, the flow rate of the mixture is 10-200 mL / min, the volume ratio of hydrogen in the mixture is 1.0-90.0%, the treatment temperature is 50-600℃, and the treatment time is 1-5 hours.

[0017] The catalyst is used in the selective hydrogenation of acetylene to produce ethylene.

[0018] The conditions for the selective hydrogenation of acetylene are as follows: the gaseous components of the selective hydrogenation of acetylene are 1.5–6.0 vol.% H2, 20 vol.% C2H4, 0.5 vol.% C2H2, with helium as the equilibrium gas, the gas flow rate is 20–80 ml / min, and the reaction temperature is 50–200℃.

[0019] The present invention has the following advantages and beneficial effects:

[0020] 1. This invention prepares supported Ni3GaC 0.7 / Ga2O3 catalyst, by using supported nickel-based carbides to replace precious metals, significantly reduces the cost of acetylene selective hydrogenation catalysts.

[0021] 2. The present invention prepares Ni3GaC by impregnation, calcination oxidation, and heat treatment with a mixture of hydrogen and carbon dioxide gas. 0.7 In the selective hydrogenation reaction performance test of acetylene with Ga2O3 catalyst, the selectivity of ethylene was significantly improved, reaching about 85%. After 18 hours of selective hydrogenation test of acetylene, the selectivity of ethylene and the catalyst activity remained basically unchanged, indicating that the catalyst has very good stability in the reaction.

[0022] 3. Compared with previous non-noble metal-based acetylene hydrogenation catalysts, this invention prepares supported Ni3GaC by heating the impregnated composite material in a mixture of hydrogen and carbon dioxide gas. 0.7 The Ga2O3 catalyst is not only easy to prepare, but also exhibits excellent performance in the selective hydrogenation of acetylene.

[0023] 4. Compared with traditional nickel-based carbide catalyst preparation methods, this invention optimizes the preparation method of interstitial carbide catalysts by regulating the catalyst structure through the interaction of reaction metal, support and carbon dioxide in a mixed gas of hydrogen and carbon dioxide, while introducing a specific ratio of support elements and interstitial carbon atoms and retaining a clean catalyst surface. Attached Figure Description

[0024] Figure 1 Ni for Comparative Example 1 x Ga y / Ga2O3, Ni3GaC from Example 1 0.7 / Ga2O3 catalyst, Ni3GaC from Example 2 0.7 XRD pattern of Ga2O3 catalyst.

[0025] Figure 2 Ni for Comparative Example 1 x Ga y / Ga2O3 and Ni3GaC from Example 1 0.7Transmission electron microscopy (TEM) image of / Ga2O3 and particle size distribution of loaded nanoparticles; where: (a) Ni x Ga y / Transmission electron microscopy image of Ga2O3; (b)Ni3GaC 0.7 / Transmission electron microscopy images of Ga2O3; insets in (a) and (b) show the corresponding Ni x Ga y and Ni3GaC 0.7 Nanoparticle size distribution diagram.

[0026] Figure 3 Ni for Comparative Example 1 x Ga y / Ga2O3 and Ni3GaC from Example 1 0.7 High-resolution transmission electron microscopy images of Ga2O3 catalysts; where: (a) is Ni x Ga y High-resolution transmission electron microscopy (TEM) images of the / Ga2O3 catalyst; (b) and (c) are Ni3GaC 0.7 High-resolution transmission electron microscopy image of Ga2O3 catalyst;

[0027] Figure 4 Ni for Comparative Example 1 x Ga y / Ga2O3 and Ni3GaC from Example 1 0.7 Selective hydrogenation performance of Ga2O3 catalyst at 180℃ for acetylene.

[0028] Figure 5 Ni3GaC as described in Example 1 0.7 Long-term stability test of Ga2O3 catalyst at 180℃. Detailed Implementation

[0029] This invention utilizes non-precious metal nickel to replace precious metal palladium, and prepares supported Ni3GaC through impregnation, calcination oxidation, and treatment with a mixed gas of hydrogen and carbon dioxide. 0.7 The invention will be further described below with reference to the Ga2O3 catalyst, in conjunction with the embodiments and accompanying drawings.

[0030] Example 1:

[0031] Preparation of supported Ni3GaC 0.7 The process using the Ga2O3 catalyst is as follows:

[0032] 1. Impregnation: Dissolve 202 mg of nickel nitrate hexahydrate in 40 ml of methanol, then add 372.8 mg of gallium oxide nanorods, and sonicate for about 1 hour to ensure uniform dispersion. Then remove the solvent methanol by rotary evaporator and dry in an oven at 100°C for 2 hours.

[0033] 2. The sample after step 1 was calcined and oxidized in an air atmosphere in a tube furnace with an air flow rate of 100 mL / min. During the calcination process, the temperature was increased to 350°C at a heating rate of 5°C / min and kept at that temperature for 2 hours. The sample was then cooled to room temperature to obtain the NiO / Ga2O3 intermediate.

[0034] 3. The sample treated in step 2 was heat-treated in a mixture of hydrogen and carbon dioxide at a flow rate of 20 ml / min, with hydrogen comprising 10 vol.%; after being kept at 500℃ for 2 hours, it was cooled to room temperature to obtain Ni3GaC. 0.7 / Ga2O3 catalyst ( Figure 1 ).

[0035] The supported Ni3GaC prepared in this embodiment 0.7 In the Ga2O3 catalyst, the Ni loading is approximately 10 wt.%.

[0036] Example 2

[0037] The difference from Example 1 is that in step 3, during the heat treatment in a mixture of hydrogen and carbon dioxide, the flow rate of the mixed gas was 20 ml / min, and the hydrogen content was 10 vol.%; after being treated at a constant temperature of 600°C for 2 hours, the temperature was lowered to room temperature to obtain Ni3GaC. 0.7 / Ga2O3 catalyst ( Figure 1 ).

[0038] The supported Ni3GaC prepared in this embodiment 0.7 In the Ga2O3 catalyst, the Ni loading is approximately 10 wt.%.

[0039] Comparative Example 1:

[0040] The difference from Example 1 is that in step 3, the sample is treated with high-purity hydrogen to obtain Ni with a Ni loading of 10 wt.%. x Ga y / Ga2O3 catalyst, in which Ni x Ga y Nickel-gallium alloy ( Figure 1 ).

[0041] The Ni3GaC prepared in Example 1 and Comparative Example 1 above 0.7 / Ga2O3 catalyst, Ni x Ga y Transmission electron microscopy images and particle size distribution of the Ga2O3 catalyst are shown below. Figure 2 As shown, Ni x Ga y / Ga2O3 and Ni3GaC 0.7High-resolution transmission electron microscopy image of Ga2O3 catalyst as shown below Figure 3 As shown.

[0042] Application example:

[0043] The Ni3GaC prepared in Example 1 and Comparative Example 1 0.7 / Ga2O3 and Ni x Ga y The Ga₂O₃ catalyst is used in the selective hydrogenation of acetylene. The application process is as follows:

[0044] Take 30mg Ni obtained above respectively x Ga y / Ga2O3 and 30mg Ni3GaC 0.7 / Ga2O3 catalyst is added to a quartz reaction tube and fixed in the constant temperature zone in the middle of the reaction bed by quartz wool.

[0045] First, pretreatment is performed: a mixture of hydrogen and helium (50 vol.% hydrogen) is introduced into the reaction tube, and the catalyst is reduced at 500°C for 2 hours. The gas flow rate is controlled at 20 mL / min using a mass flow meter.

[0046] After pretreatment, the temperature was lowered to 180°C, and then the catalyst performance was tested. Specifically, the gas composition for the acetylene hydrogenation reaction was: 3.0 vol.% H2, 20 vol.% C2H4, 0.5 vol.% C2H2, with helium as the balance gas. The above gases were introduced into the reaction tube, and the catalyst was reduced at 180°C at a flow rate of 50 mL / min.

[0047] The test results of the selective hydrogenation reaction performance of acetylene are shown in the figure. Figure 4 and Figure 5 :

[0048] Depend on Figure 4 and Figure 5 As can be seen, when the catalyst prepared in Example 1 is applied to the selective hydrogenation of acetylene, the selectivity of ethylene is significantly improved, reaching over 85%. After 18 hours of selective hydrogenation testing of acetylene, the selectivity and activity of ethylene remain essentially unchanged, indicating that the catalyst has very good stability in the reaction. Comparative Example 1 prepared Ni x Ga y The / Ga2O3 catalyst not only causes excessive hydrogenation of acetylene in the reactants to ethane, but also causes hydrogenation of ethylene in the feed gas to ethane, resulting in an ethylene selectivity of approximately -160%. Therefore, the Ni3GaC catalyst prepared in this invention... 0.7The Ga2O3 catalyst, which utilizes supported nickel-based carbides to replace noble metals, significantly improves the selectivity of ethylene in the selective hydrogenation reaction of acetylene, and the catalyst exhibits excellent stability in the reaction.

[0049] The above description is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A supported nickel-based carbide acetylene selective hydrogenation catalyst characterized by: The catalyst is formed by supporting a bimetallic carbide active component on a nanoscale gallium oxide support, the bimetallic carbide being Ni3GaC 0.7 ; The preparation method of the catalyst is as follows: first, a nickel salt is loaded on a nano-gallium oxide material by an impregnation method, then a calcination treatment is performed in air to obtain a NiO / Ga2O3 catalyst; and then a temperature treatment is performed in a mixed gas of carbon dioxide and hydrogen to obtain a supported Ni3GaC 0.7 / Ga2O3 catalyst, namely the supported nickel-based carbide acetylene selective hydrogenation catalyst.

2. The supported nickel-based carbide acetylene selective hydrogenation catalyst of claim 1, wherein: The loading of Ni in the catalyst is 1-40 wt.%.

3. A process for the preparation of a supported nickel-based carbide acetylene selective hydrogenation catalyst according to claim 1 or 2, characterized in that: The preparation method of the catalyst is as follows: first, a nickel salt is loaded on a nano-gallium oxide material by an impregnation method, then a calcination treatment is performed in air to obtain a NiO / Ga2O3 catalyst; and then a temperature treatment is performed in a mixed gas of carbon dioxide and hydrogen to obtain a supported Ni3GaC 0.7 / Ga2O3 catalyst, namely the supported nickel-based carbide acetylene selective hydrogenation catalyst.

4. The process for the preparation of a supported nickel-based carbide selective hydrogenation catalyst according to claim 3, characterized in that: The catalyst preparation method comprises the following steps: (1) dissolving a nickel salt in a solvent, then adding a nanometer gallium oxide material, ultrasonic stirring for 1-3 hours, removing the solvent to obtain a nickel salt nanometer gallium oxide composite material; drying the obtained nickel salt nanometer gallium oxide composite material at a drying temperature of 50-200℃ for 1-5 hours; (2) calcining the nickel salt nanometer gallium oxide composite material treated in step (1) in air to obtain a NiO / Ga2O3 catalyst; (3) The NiO / Ga2O3 catalyst obtained in step (2) is heat-treated in a mixed atmosphere of hydrogen and carbon dioxide, and then, after being reduced to room temperature, a Ni3GaC 0.7 / Ga2O3 supported catalyst is obtained.

5. The process for the preparation of a supported nickel-based carbide selective hydrogenation catalyst according to claim 4, characterized in that: In step (1), the nanometer gallium oxide is a gallium oxide nanorod; the nickel salt is selected from one or more of nickel acetate, nickel chloride, nickel nitrate, nickel carbonate, nickel sulfate and nickel acetylacetone; and the solvent is water, ethanol or methanol.

6. The process for the preparation of a supported nickel-based carbide selective hydrogenation catalyst according to claim 4, characterized in that: In step (2), when air is used for treatment, the air flow is 20-300 mL / min, the treatment temperature is 300-500℃, and the treatment time is 1-5 hours.

7. The process for the preparation of a supported nickel-based carbide selective hydrogenation catalyst according to claim 4, characterized in that: In step (3), when a mixed gas of hydrogen and carbon dioxide is used for heat treatment, the mixed gas flow is 10-200 mL / min, the volume ratio of hydrogen in the mixed gas is 1.0-90.0%, the treatment temperature is 50-600℃, and the treatment time is 1-5 hours.

8. Use of a supported nickel-based carbide acetylene selective hydrogenation catalyst according to claim 1 or 2, characterized in that: The catalyst of claim 1 or 2 is used in the reaction of selective hydrogenation of acetylene to prepare ethylene.

9. Use of a catalyst according to claim 8, characterized in that: The acetylene selective hydrogenation reaction gas components are 1.5-6.0 vol.% H2, 20 vol.% C2H4, 0.5 vol.% C2H2, and helium as the balance gas, the gas flow rate is 20-80 mL / min, and the reaction temperature is 50-200℃.

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