Nickel-iron alloy catalyst, preparation method and application thereof, and ethanol reforming method
By using nickel-ferroalloy catalysts, the problems of low activity, severe carbon deposits and low hydrogen selectivity in the ethanol steam reforming reaction were solved, high ethanol conversion and high hydrogen selectivity were achieved, and the carbon deposit performance of the catalyst was optimized.
Patent Information
- Application Number
- CN202510101491.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-10-17
- Filing Date
- 2025-01-22
- Publication Date
- 2025-05-30
AI Technical Summary
The existing nickel-based catalysts have problems such as low activity, severe carbon deposits leading to catalyst deactivation and low hydrogen selectivity in the ethanol steam reforming reaction.
The nickel ferroalloy catalyst is used to prepare the nickel ferroalloy catalyst for ethanol reforming by contacting a solution containing soluble nickel salt and soluble iron salt with a La2O2CO3 support, and performing drying, calcining and reducing treatment.
It significantly improves the ethanol conversion rate and hydrogen selectivity, and has excellent carbon deposit performance and can maintain high catalytic performance.
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of alcohol steam reforming, and particularly relates to a nickel-iron alloy catalyst, a preparation method and application thereof, and an ethanol reforming method. Background Art
[0002] Using renewable energy is the key to addressing global energy challenges and alleviating environmental problems. In this context, ethanol, as a renewable resource, has the advantages of high energy density, low toxicity, easy storage and transportation, and does not contain elements that can cause catalyst poisoning, making it an ideal raw material for catalytic hydrogen production.
[0003] The essence of the ethanol steam reforming reaction for hydrogen production is the process of oxidative dissociation of saturated fatty alcohols to produce hydrogen. Ethanol steam reforming for hydrogen production is a promising hydrogen production route, which helps to promote the development of clean and sustainable energy systems. However, in the process of ethanol steam reforming reaction, in addition to hydrogen production, a series of unwanted side reactions also occur, and these reactions will lead to the generation of unwanted products (CO, CH 4 、C 2 H 4 、CH 3 COCH 3 etc.).
[0004] Currently, the research on non-noble metal catalysts for catalytic ethanol steam reforming mainly focuses on nickel-based catalysts because it has a strong ability to break C-C bonds and C-H, and can efficiently catalyze ethanol steam reforming at a reaction temperature of 400-700 °C. However, there are some challenges in the application of nickel-based catalysts.
[0005] (1) Sintering of active metal nickel: In a high-temperature and steam environment, nickel particles in the nickel-based catalyst are prone to aggregation, resulting in a reduction in the catalytic active surface area, and thus leading to a decrease in the activity of the catalyst.
[0006] (2) Severe carbon deposition: During the catalytic process, due to a series of side reactions, such as the disproportionation reaction of CO and the hydrogenation reaction of CO 2 , as well as the formation of ethylene and acetone at high temperatures, these by-products will cause carbon deposition problems, which will cover the active metal surface of the catalyst and lead to complete deactivation of the catalyst.
[0007] (3) Low hydrogen selectivity: Nickel-based catalysts have high activity in the methanation reaction, resulting in an increase in the methane content in the generated hydrogen, thereby reducing the purity of hydrogen.
[0008] To solve these problems, researchers have conducted many studies, such as doping promoters in the catalyst to improve the active metal, using different carrier materials, adjusting the preparation method, etc., but there is still room for improvement. Summary of the Invention
[0009] The object of the present invention is to overcome the problems existing in the prior art, such as the low activity of nickel-based catalysts, the performance degradation or even deactivation of the catalysts caused by severe carbon deposition occurring when the reaction proceeds to a certain extent, and the low H 2 selectivity due to many side reactions in the reaction. A nickel-iron alloy catalyst, a preparation method and application thereof, and an ethanol reforming method are provided. The nickel-iron alloy catalyst of the present invention has the advantages of high ethanol conversion rate and high hydrogen selectivity for ethanol reforming, and excellent carbon deposition performance.
[0010] In order to achieve the above object, the first aspect of the present invention provides a preparation method of a nickel-iron alloy catalyst, including the following steps:
[0011] Contacting a solution containing soluble nickel salt and soluble iron salt with La 2 O 2 CO 3 support, drying, calcining, and reducing; the reduction conditions include: the temperature is 800-1000 °C, and the time is 1-10 h;
[0012] The soluble nickel salt is calculated as nickel, the soluble iron salt is calculated as iron, and the mass ratio of the soluble nickel salt to the soluble iron salt is 1:0.2-3;
[0013] In the nickel-iron alloy catalyst, the total mass of iron and nickel is 3-15 wt% of the total weight of the catalyst.
[0014] The second aspect of the present invention provides a nickel-iron alloy catalyst prepared by the preparation method described in the present invention.
[0015] The third aspect of the present invention provides an application of the nickel-iron alloy catalyst described in the present invention in alcohol steam reforming.
[0016] The fourth aspect of the present invention provides an ethanol reforming method, which includes:
[0017] Contacting water and ethanol in the presence of a catalyst, and the catalyst includes the nickel-iron alloy catalyst described in the present invention.
[0018] Through the above technical solution, the nickel-iron alloy catalyst prepared by the preparation method described in the present invention has the advantages of high ethanol conversion rate and high hydrogen selectivity for ethanol reforming, and excellent carbon deposition performance. Specific Embodiments
[0019] The endpoints and any values in the ranges disclosed herein are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein.
[0020] The first aspect of the present invention provides a method for preparing a nickel-iron alloy catalyst, comprising the following steps:
[0021] Contacting a solution containing a soluble nickel salt and a soluble iron salt with a La 2 O 2 CO 3 support, drying, calcining, and reducing; the reduction conditions include: a temperature of 800 - 1000 °C and a time of 1 - 10 h;
[0022] The soluble nickel salt is calculated as nickel, the soluble iron salt is calculated as iron, and the mass ratio of the soluble nickel salt to the soluble iron salt is 1:0.2 - 3;
[0023] In the nickel-iron alloy catalyst, the total mass of iron and nickel is 3 - 15 wt% of the total weight of the catalyst.
[0024] According to a preferred embodiment of the present invention, the soluble nickel salt is calculated as nickel, the soluble iron salt is calculated as iron, and in the solution containing the soluble nickel salt and the soluble iron salt, the concentration of the soluble nickel salt and the soluble iron salt is 0.05 - 0.5 mol / L.
[0025] According to a preferred embodiment of the present invention, the calcination conditions include: a temperature of 650 - 800 °C and a time of 1 - 8 h.
[0026] According to a preferred embodiment of the present invention, the reduction is carried out under the condition of a reducing gas atmosphere; preferably, the reducing gas is hydrogen, and the volume content of the reducing gas is 6 - 12%; in the examples of the present invention, exemplarily, a hydrogen-nitrogen mixture with a hydrogen volume ratio of 10% is used as the reducing gas atmosphere.
[0027] According to a preferred embodiment of the present invention, the drying conditions include: a temperature of 80 - 120 °C and a time of 1 - 24 h.
[0028] According to a preferred embodiment of the present invention, the solution containing the soluble nickel salt and the soluble iron salt further contains urea, and the urea concentration is 0.02 - 0.1 mol / L, which can improve the ethanol conversion rate and hydrogen selectivity.
[0029] The second aspect of the present invention provides a nickel-iron alloy catalyst prepared by the preparation method described in the present invention.
[0030] According to a preferred embodiment of the present invention, the nickel-iron alloy is supported on lanthanum oxide, and the mass ratio of nickel to iron is 1:0.2 - 3;
[0031] According to a preferred embodiment of the present invention, the mass of the nickel-iron alloy is 3 - 15 wt% of the total weight of the catalyst.
[0032] The third aspect of the present invention provides an application of the nickel-iron alloy catalyst described in the present invention in alcohol steam reforming.
[0033] According to a preferred embodiment of the present invention, the alcohol is selected from C1 - C4 alcohols.
[0034] The fourth aspect of the present invention provides a method for ethanol reforming, which includes:
[0035] Contacting water and ethanol in the presence of a catalyst, where the catalyst includes the nickel-iron alloy catalyst described in the present invention.
[0036] According to a preferred embodiment of the present invention, the contact conditions include: GHSV = 12000 - 18000 h -1 , the molar ratio of water to ethanol is 1:1 - 3, and the temperature is 400 - 650 °C.
[0037] The present invention will be described in detail below through examples.
[0038] In the following examples, the steps of the ethanol reforming for hydrogen production are as follows: Load 0.1 g of the catalyst into an atmospheric pressure fixed-bed reactor, and the inner diameter of the quartz reaction tube in the reactor is 6 mm; After in-situ pretreatment for 1 h under the conditions of a heat preservation temperature T = 600 °C and a hydrogen flow rate of 50 mL / min, carry out the ethanol reforming for hydrogen production reaction, where the reaction conditions are GHSV = 16000 h -1 , the molar ratio of water to ethanol is 1:2, and the reaction temperature T = 600 °C. After the reaction products are cooled by a cold trap, gaseous products (H 2 , CO 2 , CH 4 , CO, C 2 H 4 ) and reaction residue liquid (CH 3 CH 2 OH and H 2 O) are obtained. Among them, the composition of the gaseous products is analyzed by Agilent chromatography, and the reaction residue liquid is analyzed and detected by Shimadzu chromatography.
[0039] In the catalyst, the content of each element is measured by ICP.
[0040] Example 1
[0041] Dissolve nickel nitrate and iron nitrate in water to prepare an aqueous solution with nickel at 0.1 mol / L and iron at 0.1 mol / L. Take 10 mL of this solution and impregnate it with 1 g of La 2 O 2 CO 3 After drying at 90 °C for 10 h, place it in a muffle furnace and heat it to 700 °C at a heating rate of 5 °C / min for roasting for 6 h; then use a mixed gas atmosphere with a flow rate of 50 mL / min and a hydrogen volume percentage of 10% H 2 -N 2 Reduce it at 950 °C for 3 h to prepare a nickel-iron alloy catalyst.
[0042] In the catalyst, the nickel-iron alloy accounts for 11.5% of the total weight of the catalyst, and lanthanum oxide accounts for 88.5% of the total weight of the catalyst. Evaluate the catalyst according to the aforementioned evaluation method. The results of the 3-hour evaluation are shown in Table 1, and the results of the 18-hour evaluation are shown in Table 2.
[0043] Example 2
[0044] Dissolve nickel nitrate and iron nitrate in water to prepare an aqueous solution with nickel at 0.08 mol / L and iron at 0.12 mol / L. Take 10 mL of this solution and impregnate it with 1 g of La 2 O 2 CO 3 After drying at 90 °C for 10 h, place it in a muffle furnace and heat it to 700 °C at a heating rate of 5 °C / min for roasting for 6 h; then use a mixed gas atmosphere with a flow rate of 50 mL / min and a hydrogen volume percentage of 10% H 2 -N 2 Reduce it at 900 °C for 6 h to prepare a nickel-iron alloy catalyst.
[0045] In the catalyst, the nickel-iron alloy accounts for 11.6% of the total weight of the catalyst, and lanthanum oxide accounts for 88.4% of the total weight of the catalyst. Evaluate the catalyst according to the aforementioned evaluation method. The results of the 3-hour evaluation are shown in Table 1, and the results of the 18-hour evaluation are shown in Table 2.
[0046] Example 3
[0047] Dissolve nickel nitrate and iron nitrate in water to prepare an aqueous solution with nickel at 0.15 mol / L and iron at 0.05 mol / L. Take 10 mL of this solution and impregnate it with 1 g of La 2 O 2 CO 3 After drying at 90 °C for 10 h, place it in a muffle furnace and heat it to 700 °C at a heating rate of 5 °C / min for roasting for 6 h; then use a mixed gas atmosphere with a flow rate of 50 mL / min and a hydrogen volume percentage of 10% H 2 -N 2The nickel-iron alloy catalyst was prepared by reduction at 1000 °C for 2 h in a mixed gas atmosphere.
[0048] In the catalyst, the nickel-iron alloy accounted for 11.42% of the total weight of the catalyst, and lanthanum oxide accounted for 88.58% of the total weight of the catalyst. The catalyst was evaluated according to the aforementioned evaluation method. The results of the 3-hour evaluation are shown in Table 1, and the results of the 18-hour evaluation are shown in Table 2.
[0049] Example 4
[0050] According to the method of Example 1, the difference is that an aqueous solution with nickel at 0.1 mol / L, iron at 0.1 mol / L, and urea content at 0.02 mol / L was prepared. The other conditions were the same as those in Example 1, and a nickel-iron alloy catalyst was prepared. In the catalyst, the nickel-iron alloy accounted for 11.5% of the total weight of the catalyst, and lanthanum oxide accounted for 88.5% of the total weight of the catalyst.
[0051] The catalyst was evaluated according to the aforementioned evaluation method. The results of the 3-hour evaluation are shown in Table 1, and the results of the 18-hour evaluation are shown in Table 2.
[0052] Comparative Example 1
[0053] According to the method of Example 1, the difference is that nickel nitrate was dissolved in water to prepare an aqueous solution with nickel element at 0.2 mol / L. The other conditions were the same as those in Example 1, and a catalyst was prepared. In the catalyst, nickel accounted for 11.71% of the total weight of the catalyst, and lanthanum oxide accounted for 88.29% of the total weight of the catalyst.
[0054] The catalyst was evaluated according to the aforementioned evaluation method. The results of the 3-hour evaluation are shown in Table 1, and the results of the 18-hour evaluation are shown in Table 2.
[0055] Comparative Example 2
[0056] According to the method of Example 1, the difference is that La 2 O 2 CO 3 was replaced by lanthanum oxide. Specifically,
[0057] Nickel nitrate and iron nitrate were dissolved in water to prepare an aqueous solution with nickel at 0.1 mol / L and iron at 0.1 mol / L. 10 mL of this solution was impregnated with 0.885 g of La 2 O 3 . After drying at 90 °C for 10 h, it was calcined in a muffle furnace at a heating rate of 5 °C / min to 700 °C for 6 h; then, using a flow rate of 50 mL / min and a hydrogen volume percentage of 10% H 2 -N 2 mixed gas atmosphere, the nickel-iron alloy catalyst was prepared by reduction at 950 °C for 3 h.
[0058] In the catalyst, the nickel-iron alloy accounts for 11.5% of the total weight of the catalyst, and lanthanum oxide accounts for 88.5% of the total weight of the catalyst. The catalyst was evaluated according to the aforementioned evaluation method. The results of the 3-hour evaluation are shown in Table 1, and the results of the 18-hour evaluation are shown in Table 2.
[0059] Table 1
[0060] Example Ethanol conversion rate (%) Hydrogen selectivity (%) Example 1 99.12 68.33 Example 2 99.01 67.98 Example 3 98.93 67.52 Example 4 99.63 73.46 Comparative Example 1 98.9 60.31 Comparative Example 2 99 61.55
[0061] Table 2
[0062] Example Ethanol conversion rate (%) Hydrogen selectivity (%) Example 1 98.35 55.46 Example 2 98.13 53.89 Example 3 98.05 53.53 Example 4 99.01 59.96 Comparative Example 1 80.26 37.62 Comparative Example 2 86.39 40.17
[0063] From the results in Table 1 and Table 2, it can be seen that the catalyst prepared by the preparation method described in the present invention, when used for ethanol reforming, can significantly improve the ethanol conversion rate and hydrogen selectivity. Moreover, after 18 hours of evaluation, it can still maintain about 80% of the catalytic performance and has excellent carbon deposition performance.
[0064] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.
Claims
1. A method for preparing a nickel-iron alloy catalyst, characterized in that: The following steps are involved: A solution containing a soluble nickel salt and a soluble iron salt is contacted with a La2O2CO3 carrier, and then dried, calcined, and reduced; the reduction conditions include: a temperature of 800-1000°C and a time of 1-10 hours; The soluble nickel salt is calculated as nickel, the soluble iron salt is calculated as iron, and the mass ratio of the soluble nickel salt to the soluble iron salt is 1:0.2-3; In the nickel-iron alloy catalyst, the total mass of iron and nickel is 3-15wt% of the total weight of the catalyst.
2. The preparation method according to claim 1, wherein The soluble nickel salt is calculated as nickel, the soluble iron salt is calculated as iron, and in the solution containing the soluble nickel salt and the soluble iron salt, the average concentration of the soluble nickel salt and the soluble iron salt is 0.05-0.5 mol / L.
3. The preparation method according to claim 1 or 2, wherein The calcination conditions include: temperature of 650-800°C and time of 1-8h.
4. The preparation method according to claim 1 or 2, wherein: The reduction is carried out under the condition of a reducing gas atmosphere; Preferably, the reducing gas is hydrogen; and / or The volume content of reducing gas is 6-12%.
5. The preparation method according to claim 1 or 2, wherein: Drying conditions include: temperature of 80-120°C and time of 1-24h.
6. The preparation method according to claim 1 or 2, wherein: The solution containing the soluble nickel salt and the soluble iron salt also contains urea, and the urea concentration is 0.01-0.1 mol / L.
7. The nickel-iron alloy catalyst prepared by the preparation method according to any one of claims 1 to 6.
8. The nickel-iron alloy catalyst according to claim 7, wherein The nickel-iron alloy is loaded on lanthanum oxide, and the mass ratio of nickel to iron is 1:0.2-3; The mass of the nickel-iron alloy is 3-15wt% of the total weight of the catalyst.
9. Use of the nickel-iron alloy catalyst according to claim 7 or 8 in alcohol steam reforming, preferably, the alcohol is selected from C1-C4 alcohols.
10. An ethanol reforming method, characterized in that: The method includes: contacting water and ethanol in the presence of a catalyst, wherein the catalyst comprises the nickel-iron alloy catalyst of claim 7 or 8; Preferably, the contact conditions include: GHSV = 12000-18000h -1 , the molar ratio of water to ethanol is 1:1-3, and the temperature is 400-650°C.