Nickel-based catalysts, processes for their preparation and use
By preparing a silicon carbide-supported nickel-indium composite oxide catalyst, the problem of insufficient anti-coking performance of nickel-based catalysts in the methane-carbon dioxide reforming reaction was solved, achieving high catalyst stability and long lifespan, suitable for the methane-carbon dioxide reforming to syngas reaction.
Patent Information
- Application Number
- CN202310802938.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-03
- Publication Date
- 2026-02-17
- Estimated Expiration
- 2043-07-03
AI Technical Summary
Existing nickel-based catalysts have insufficient resistance to carbon deposition in the reaction of methane reforming to syngas, resulting in a short catalyst lifespan and difficulty in maintaining stability for a long time under high temperature conditions.
A nickel-indium/silicon carbide composite oxide catalyst was formed by dissolving nickel and indium salts in an organic solvent, uniformly impregnating the β-phase silicon carbide support, and then calcining. The metal-support interaction was optimized by combining reduction and reforming reaction conditions.
Under conditions of 800℃, atmospheric pressure, and space velocity of 36 L·h⁻¹·g⁻¹, the catalyst showed no significant carbon deposition within 100 h, with CH₄ conversion exceeding 50% and CO₂ conversion exceeding 70%, significantly improving the catalyst's stability and reaction efficiency.
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Figure CN117225438B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of catalyst preparation technology for methane-carbon dioxide reforming to syngas, specifically to a nickel-based catalyst, its preparation method, and its application. Background Technology
[0002] Energy and the environment are the foundation and driving force for human economic and social development. Adjusting and transforming the energy consumption structure is a crucial strategic policy for the global energy and environmental industries. Catalytic reforming (DRM) technology can effectively convert two greenhouse gases, CH4 and CO2, into syngas—H2 and CO—important industrial feedstocks. The produced syngas is then used in Fischer-Tropsch synthesis to further produce various liquid fuels and high-value-added chemicals. Therefore, the DRM reaction can both meet energy consumption demands and mitigate the greenhouse effect, occupying a vital strategic energy position in economic and social development.
[0003] Literature reports on DRM catalysts began in 1928, with Fisher and Tropsch reporting the CH4 reforming activity of transition metals Ni, Co, and Fe. By the late 20th century, DRM catalyst systems were largely established, generally categorized into noble metal catalysts such as Ru, Rh, Pd, and Pt, and non-noble metal catalysts such as Ni, Co, Fe, and Mo. Noble metal-based catalysts exhibit high activity, but their industrial application is limited by high costs. Conversely, non-noble metal-based catalysts, represented by Ni, combine advantages in catalytic performance, price, and availability, showing promising prospects for industrial applications. Abdullah et al. reviewed the research progress of Ni-based catalysts in the DRM reaction, arguing that resistance to coking is a key indicator for evaluating the structure and performance of a Ni-based catalyst. Metal-support interactions directly affect the catalyst's resistance to coking. Therefore, the selection of the support, promoters, and reaction conditions is crucial for the construction of Ni-based catalysts. Summary of the Invention
[0004] To address the shortcomings of existing technologies, the first technical problem this invention aims to solve is to provide a novel nickel-based catalyst with strong resistance to carbon deposition. This catalyst, used in the methane-carbon dioxide reforming reaction to syngas, can meet the requirements for catalyst lifespan at 800°C, atmospheric pressure, and a space velocity of 36 L / h. -1 ·g -1 Under these conditions, it remains stable after 100 hours of use, with no obvious carbon buildup.
[0005] The second technical problem to be solved by the present invention is to provide a method for preparing the above-mentioned catalyst.
[0006] To solve the first technical problem mentioned above, the nickel-based catalyst provided by the present invention is a nickel-indium composite oxide supported on silicon carbide, wherein the silicon carbide support is a β phase.
[0007] To solve the second technical problem mentioned above, the catalyst of the present invention is prepared using the following technical solution:
[0008] 1) Prepare a solution by dissolving nickel salt and indium salt in an organic solvent.
[0009] 2) While rotating fully in a rotary evaporator, the β-phase silicon carbide support is uniformly immersed in the solution prepared in step 1) multiple times.
[0010] 3) After complete impregnation, dry it in an oven and then calcine it in a muffle furnace to obtain the nickel-based catalyst of the present invention, namely, the nickel-indium composite oxide catalyst supported on silicon carbide.
[0011] Preferably, the nickel salt in step 1) is a nickel nitrate and its hydrate; the indium salt is an indium nitrate and its hydrate.
[0012] Preferably, the solvent in step 1) is anhydrous ethanol.
[0013] Preferably, in step 1), the mass ratio of nickel to indium is 10 to 15:1.
[0014] Preferably, the number of times the immersion is performed in step 2) is 2 to 4.
[0015] Preferably, in step 2), the mass ratio of silicon carbide to nickel in the β phase is 12 to 18:1.
[0016] Preferably, in step 3), the muffle furnace calcination temperature is 700–800°C, and the programmed heating rate is 2–3°C / min.
[0017] This invention also provides the application of the above-mentioned nickel-based catalyst in the methane-carbon dioxide reforming reaction, and the application process is as follows:
[0018] The catalyst was loaded into a reaction tube, and reduction and catalytic reforming reactions were carried out sequentially in a fixed-bed reactor. The reduction conditions were as follows:
[0019] 1) Heating at a certain rate under an inert atmosphere.
[0020] 2) Introduce hydrogen gas for reduction.
[0021] Preferably, nitrogen gas is introduced during the heating process in step 1) to provide an inert atmosphere.
[0022] Preferably, the heating rate in step 1) is 80–120 °C / h.
[0023] Preferably, the reduction temperature in step 2) is 550–700°C.
[0024] Preferably, the hydrogen flow rate in step 2) is 20-40 ml / min.
[0025] The catalytic reforming reaction conditions are as follows: 1) After the reduction is completed, the temperature is raised to 800℃ at a certain rate; 2) At 800℃, the gas providing the inert atmosphere is gradually switched to a mixture of CH4, CO2 and the gas providing the inert atmosphere with a total flow rate of 40-120 ml / min to carry out the reforming reaction.
[0026] Preferably, the gas used in step 1) for heating is nitrogen, and the heating rate is 80-120℃ / h.
[0027] Preferably, the reforming reaction conditions in step 2) are a mixture of CH4:CO2:gas providing an inert atmosphere = 1:1:2, at atmospheric pressure.
[0028] The results showed that at 800℃, normal pressure, and a space velocity of 36 L·h -1 ·g -1 Under these conditions, the CH4 conversion rate is over 50%, the CO2 conversion rate is over 70%, and the catalyst shows no significant carbon buildup after 100 hours of use, remaining stable (after 100 hours of reaction, the CH4 conversion rate is 67%, and the CO2 conversion rate is 72%).
[0029] Compared with the prior art, the advantages and beneficial effects of the technical solution of the present invention are as follows:
[0030] (1) The nickel-indium / silicon carbide catalyst has high stability and no obvious carbon buildup after 100 hours of use.
[0031] (2) The indium additive described in this invention helps CO2 adsorption and dissociation, thereby improving reaction efficiency.
[0032] (3) The addition of the indium additive described in this invention can enhance the interaction between the metal and the support. Therefore, the addition of the indium additive plays a role in stabilizing nickel particles, preventing sintering, resisting carbon deposition, and extending the catalyst life to a certain extent. Attached Figure Description
[0033] Figure 1 This is the X-ray diffraction (XRD) pattern of the nickel-indium / silicon carbide catalyst synthesized in Example 1.
[0034] Figure 2 This is a high-resolution transmission electron microscope (HR-TEM) image of the nickel-indium / silicon carbide catalyst synthesized in Example 1.
[0035] Figure 3 These are HAADF-STEM and EDS-Mapping images of the nickel-indium / silicon carbide catalyst synthesized in Example 1.
[0036] Figure 4 These are the hydrogen-temperature-programmed reduction (H2-TPR) spectra of the nickel-indium / silicon carbide catalyst, nickel / silicon carbide catalyst, and indium / silicon carbide catalyst synthesized in Examples 1, 3, and 4.
[0037] Figure 5 This is the experimental result of the lifetime of the nickel-indium / silicon carbide catalyst for the methane-carbon dioxide reforming reaction at 800°C in Example 5.
[0038] Figure 6 This is the experimental result of the lifetime of the nickel-indium / silicon carbide catalyst (water as solvent) catalyzing the methane-carbon dioxide reforming reaction at 800°C in Example 6 (Comparative Example).
[0039] Figure 7 This is the experimental result of the lifetime of the nickel / silicon carbide catalyst catalyzing the methane-carbon dioxide reforming reaction at 800°C in Example 7 (Comparative Example).
[0040] Figure 8 This is the experimental result of the lifetime of the indium / silicon carbide catalyst catalyzing the methane-carbon dioxide reforming reaction at 800°C in Example 8 (Comparative Example).
[0041] Figure 9 The results are from thermogravimetric analysis of methane-carbon dioxide reforming reaction catalyzed by the nickel-indium / silicon carbide catalyst at 800°C in Example 5. Detailed Implementation
[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the following embodiments are only for illustrating the technical solutions and effects of the present invention, and are not intended to limit the scope of protection of the present invention.
[0043] Examples 1, 2, 3, and 4 are examples of the preparation of nickel-indium / silicon carbide catalyst, comparative catalyst nickel-indium / silicon carbide catalyst (water as solvent), comparative catalyst nickel / silicon carbide catalyst, and comparative catalyst indium / silicon carbide catalyst, respectively.
[0044] Example 5 is an example to investigate the service life of the catalyst prepared in Example 1 in the methane-carbon dioxide reforming reaction at 800°C;
[0045] Examples 6, 7, and 8 (comparative examples) are examples to investigate the service life of the catalysts prepared in Examples 2, 3, and 4 for catalyzing the methane-carbon dioxide reforming reaction at 800°C.
[0046] Example 1
[0047] A method for preparing a nickel-indium / silicon carbide catalyst, comprising the following steps:
[0048] 0.446 g of nickel nitrate hexahydrate and 0.021 g of indium nitrate hydrate were dissolved in 2 ml of anhydrous ethanol to obtain an impregnation solution. Under full rotation in a rotary evaporator, 1.40 g of β-phase silicon carbide support was uniformly impregnated in the above solution in three portions. The solution was then dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at a rate of 2 °C / min to 750 °C for 5 h to obtain the nickel-indium / silicon carbide catalyst of the present invention, denoted as Ni-In / SiC.
[0049] The X-ray diffraction patterns of the nickel-indium / silicon carbide catalyst prepared in this embodiment before and after reduction are as follows: Figure 1 As shown, the high-resolution transmission electron microscope image is as follows: Figure 2 As shown, HAADF-STEM and EDS-Mapping images are as follows: Figure 3 As shown.
[0050] Depend on Figure 1 It can be seen that the fresh catalyst obtained in Example 1 exhibits characteristic diffraction peaks of NiO, which transform into characteristic diffraction peaks of Ni after reduction. For example... Figure 2 The display shows that area 1 ( Figure 2 In the area within the right-hand box, a crystal plane spacing of 0.24 nm can be observed, belonging to the NiO(111) crystal plane; in area 2 ( Figure 2 In the area within the left box, a 0.26 nm interplanar spacing can be observed, belonging to the SiC(111) crystal plane. However, due to the low indium content, no diffraction peaks were observed in the XRD pattern. Figure 3 The results show that indium and nickel are successfully bonded together, stabilizing the nickel particles. According to... Figure 2 and Figure 3 In the Ni-In / SiC catalyst synthesized in Example 1, the active metal Ni forms a semi-embedded structure, which enhances the metal-support interaction.
[0051] Example 2 (Comparative Example)
[0052] A method for preparing a nickel-indium / silicon carbide catalyst, comprising the following steps:
[0053] 0.446 g of nickel nitrate hexahydrate and 0.021 g of indium nitrate hydrate were dissolved in 2 ml of water to obtain an impregnation solution. 1.40 g of β-phase silicon carbide support was uniformly impregnated in the above solution in three portions while being fully rotated in a rotary evaporator. The solution was then dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at a rate of 2 °C / min to 750 °C for 5 h to obtain the nickel-indium / silicon carbide catalyst of the present invention, denoted as Ni-In / SiC (water as solvent).
[0054] Example 3 (Comparative Example)
[0055] A method for preparing a nickel / silicon carbide catalyst, comprising the following steps:
[0056] 0.446 g of nickel nitrate hexahydrate was dissolved in 2 ml of anhydrous ethanol to obtain an impregnation solution. 1.41 g of silicon carbide support was evenly impregnated into the above solution in multiple portions while being fully rotated in a rotary evaporator. The solution was then dried in an oven at 80 °C for 12 h, and then calcined in a muffle furnace at a rate of 2 °C / min to 750 °C for 5 h to obtain the nickel / silicon carbide catalyst, denoted as Ni / SiC.
[0057] Example 4 (Comparative Example)
[0058] A method for preparing an indium / silicon carbide catalyst, comprising the following steps:
[0059] 0.021 g of indium nitrate hydrate was dissolved in 2 ml of anhydrous ethanol to obtain an impregnation solution. 1.48 g of silicon carbide support was evenly impregnated in the above solution in multiple portions while being fully rotated in a rotary evaporator. The solution was then dried in an oven at 80 °C for 12 h, and then placed in a muffle furnace and calcined at 750 °C for 5 h at a rate of 2 °C / min to obtain the indium / silicon carbide catalyst of the present invention, denoted as In / SiC.
[0060] The hydrogen-temperature-programmed reduction spectra of the nickel-indium / silicon carbide catalyst, nickel / silicon carbide catalyst, and indium / silicon carbide catalyst prepared in Examples 1, 3, and 4 are as follows: Figure 4 As shown, the results indicate that the introduction of indium increases the reduction temperature and enhances the interaction between the metal and the support, thereby improving the stability of nickel nanoparticles and increasing catalyst lifetime.
[0061] Example 5
[0062] 0.2 g of the Ni-In / SiC catalyst prepared in Example 1 was weighed and loaded into a reaction tube. Reduction and catalytic reforming reactions were carried out sequentially in a fixed-bed reactor. The reduction conditions were: under a N2 atmosphere, the temperature was first increased to 600°C at a rate of 100°C / h, and then reduced for 3 h at this temperature in an H2 atmosphere with a flow rate of 30 mL / min. The reforming reaction conditions were: after reduction, the temperature was increased to 800°C at a rate of 100°C / h under an inert atmosphere, and then the N2 was gradually switched to a mixed gas (CH4:CO2:N2 = 1:1:2) with a total flow rate of 120 mL / min for the reforming reaction, with a space velocity of 36 L·h⁻¹. -1 ·g -1 At atmospheric pressure. The reaction products (H2, CO, CO2, CH4) were passed through a six-way valve and detected by GC-3000 gas chromatography with a TCD detector. The catalytic activity and lifetime of the catalyst at 800℃ were investigated, and the results are shown in [Figure number missing]. Figure 5 As shown.
[0063] Experimental results are as follows Figure 5 This indicates that at a reaction temperature of 800℃, the Ni-In / SiC catalyst prepared in this invention can achieve a CH4 conversion rate of over 50% and a CO2 conversion rate of over 70%, and remain stable within 100 hours (after 100 hours of reaction, the CH4 conversion rate is 67% and the CO2 conversion rate is 72%). Figure 9 The TG results of the catalyst after the reaction show that there is no significant carbon deposition, indicating that the Ni-In / SiC catalyst has excellent anti-carbon deposition properties. Therefore, the Ni-In / SiC catalyst described in this invention can achieve high stability in the methane-carbon dioxide reforming reaction.
[0064] Example 6 (Comparative Example)
[0065] 0.2 g of the Ni-In / SiC (water as solvent) catalyst prepared in Example 2 was weighed and loaded into a reaction tube. Reduction and catalytic reforming reactions were carried out sequentially in a fixed-bed reactor. The reduction conditions were: under a N2 atmosphere, the temperature was first increased to 600°C at a rate of 100°C / h, and then reduced for 3 h at this temperature in an H2 atmosphere with a flow rate of 30 mL / min. The reforming reaction conditions were: after reduction, the temperature was increased to 800°C at a rate of 100°C / h under an inert atmosphere, and then the N2 was gradually switched to a mixed gas (CH4:CO2:N2 = 1:1:2) with a total flow rate of 120 mL / min for the reforming reaction, with a space velocity of 36 L·h⁻¹. -1 ·g -1 At atmospheric pressure. The reaction products (H2, CO, CO2, CH4) were passed through a six-way valve and detected by GC-3000 gas chromatography with a TCD detector. The catalytic activity and lifetime of the catalyst at 800℃ were investigated, and the results are shown in [Figure number missing]. Figure 6 As shown.
[0066] Experimental results are as follows Figure 6 This indicates that at a reaction temperature of 800℃, the conversion rate of CH4 using the catalyst prepared in this invention reaches about 30%, and the conversion rate of CO2 reaches more than 50%, remaining stable within 25 hours. However, compared with the Ni-In / SiC catalyst using ethanol as a solvent, both the conversion rate and the H2 / CO ratio are reduced.
[0067] Example 7 (Comparative Example)
[0068] 0.2 g of Ni / SiC catalyst was weighed and loaded into a reaction tube, and reduction and catalytic reforming reactions were carried out sequentially in a fixed-bed reactor. The reduction conditions were as follows: the temperature was first increased to 600 °C at a rate of 100 °C / h, and then reduced for 3 h at this temperature in an H2 atmosphere with a flow rate of 30 mL / min. The reforming reaction conditions were as follows: after reduction, the temperature was increased to 800 °C at a rate of 100 °C / h, and then the N2 was gradually switched to a mixed gas with a total flow rate of 120 mL / min at 800 °C for the reforming reaction, with a space velocity of 36 L·h⁻¹. -1 ·g -1 At atmospheric pressure. The reaction products (H2, CO, CO2, CH4) were passed through a six-way valve and detected by GC-3000 gas chromatography with a TCD detector. The catalytic activity and lifetime of the catalyst at 800℃ were investigated, and the results are shown in [Figure number missing]. Figure 7 As shown.
[0069] The results are as follows Figure 7 This indicates that the comparative catalyst had low catalytic activity. This, in turn, proves that the introduction of indium in this invention enhances the metal-support interaction and improves catalytic activity.
[0070] Example 8 (Comparative Example)
[0071] 0.2 g of In / SiC catalyst was taken and tested under the exact same conditions as in Examples 5, 6, and 7 to evaluate its activity and lifetime. The results are as follows: Figure 8 As shown in the figure. The results indicate that the comparative catalyst has no catalytic activity at a reaction temperature of 800℃.
Claims
1. A nickel-based catalyst characterized in that, The nickel-based catalyst is a silicon carbide supported nickel-indium composite oxide, and the silicon carbide carrier is in a beta phase; the nickel-based catalyst is prepared by the following method: 1) dissolving nickel salt and indium salt in anhydrous ethanol to prepare a solution; 2) under sufficient rotation in a rotary evaporator, the beta phase silicon carbide carrier is uniformly immersed in the solution prepared in step 1) in multiple times; 3) after complete immersion, drying in an oven, and then calcination in a muffle furnace, the nickel-based catalyst, i.e. the silicon carbide supported nickel-indium composite oxide catalyst, is obtained.
2. A process for the preparation of a nickel-based catalyst, characterized in that, The method comprises the following steps: 1) dissolving nickel salt and indium salt in anhydrous ethanol to prepare a solution; 2) under sufficient rotation in a rotary evaporator, the beta phase silicon carbide carrier is uniformly immersed in the solution prepared in step 1) in multiple times; 3) after complete immersion, drying in an oven, and then calcination in a muffle furnace, the nickel-based catalyst, i.e. the silicon carbide supported nickel-indium composite oxide catalyst, is obtained.
3. The method of making a nickel-based catalyst according to claim 2, wherein, The nickel salt in step 1) is a nitrate salt of nickel and its hydrate; the indium salt is a nitrate salt of indium and its hydrate.
4. The process for the preparation of a nickel-based catalyst according to claim 2 or 3, characterized in that, The mass ratio of nickel to indium in step 1) is 10-15:
1.
5. The process for the preparation of a nickel-based catalyst according to claim 2 or 3, characterized in that, The number of immersions in step 2) is 2-4 times.
6. The process for the preparation of a nickel-based catalyst according to claim 2 or 3, characterized in that, The mass ratio of beta phase silicon carbide to nickel in step 2) is 12-18:
1.
7. The process for the preparation of a nickel-based catalyst according to claim 2 or 3, characterized in that, The muffle furnace calcination temperature in step 3) is 700-800℃, and the programmed heating rate is 2-3℃ / min.
8. Use of the catalyst according to claim 1 in the reaction of carbon dioxide with methane, characterized in that, The application process is: The catalyst is loaded into a reaction tube, and reduction and catalytic reforming reactions are sequentially performed on a fixed bed reactor; The reduction conditions are: 1) heating at a certain rate under an inert atmosphere; 2) reduction by introducing hydrogen; The catalytic reforming reaction conditions are: 1) after the reduction is completed, heating at a certain rate to 800℃; 2) at 800℃, gradually switching the gas providing an inert atmosphere to a mixed gas of CH4, CO2 and the gas providing an inert atmosphere with a total flow rate of 40-120ml / min for reforming reaction.