Tubular ferronickel alloy membrane and method for preparing and loading catalyst layer
By using a method of porous inner surface of Ni-Fe alloy membrane and two-step catalyst loading, the problem of difficult catalyst loading in traditional dense metal membranes was solved, achieving high efficiency in catalytic performance and hydrogen permeation performance, and improving the overall performance of the membrane reactor.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTHEAST UNIV
- Filing Date
- 2026-04-02
- Publication Date
- 2026-07-31
AI Technical Summary
Traditional dense and smooth metal membrane catalysts are difficult to load effectively, resulting in poor catalytic performance. Furthermore, the traditional split design introduces mass transfer resistance and interfacial contact thermal resistance problems, which limit the application of membrane materials in catalytic reactors.
The inner surface of the Ni-Fe alloy film is porousened, and a porous network structure is formed by wet chemical etching. The catalyst layer is loaded in a two-step process: first, a stable oxide support layer is formed, and then the catalytically active components are loaded.
It improves catalytic activity and hydrogen permeation, simplifies reactor design, enhances mass/heat transfer efficiency, and achieves highly efficient integrated catalytic reaction.
Smart Images
Figure CN122484751A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of metal membrane catalytic hydrogen permeation technology, and in particular to a tubular nickel-iron alloy membrane and a method for preparing and supporting a catalyst layer. Background Technology
[0002] Tubular dense metal membranes, a type of self-supporting dense metal membrane, possess excellent mechanical strength and hydrogen selectivity, making them ideal candidate materials for reaction-separation coupling. With their superior hydrogen permeation performance and structural stability, they show broad application prospects in membrane reactors, particularly in catalytic processes involving hydrogenation and dehydrogenation requiring online hydrogen separation and supply. However, when tubular dense metal membranes are used as catalytic reaction supports, the inner surface of the membrane tube typically exhibits a highly smooth, low specific surface area dense metallic state. This interfacial characteristic significantly limits the effective and stable loading of subsequent catalytic functional layers. The poor wettability of catalyst precursors or sols on smooth surfaces makes it difficult to form a uniform coating, and during subsequent drying, calcination, and reaction processes, insufficient interfacial adhesion easily leads to peeling, cracking, or agglomeration, resulting in discontinuous catalytic layers, uneven distribution of active sites, and severely reduced stability. Therefore, attempts to directly utilize the inner surface of the membrane tube as the catalytic reaction site often fail to achieve ideal catalytic performance and long-term stability, which essentially limits the synergistic effect of the membrane material's dual functions of "membrane separation" and "catalytic wall," hindering the construction of high-performance integrated membrane catalytic reactors.
[0003] To address these challenges, traditional technologies generally adopt an "avoidance" strategy, abandoning efforts to directly catalytically modify the inner surface of the membrane tube and instead externalizing the catalytic function to the outside of the membrane tube. In typical conventional membrane reactor configurations, the dense metal membrane tube primarily acts as a pure separation medium, while the catalytically active components are stacked on the outside of the membrane tube as independent particle-filled beds or loaded onto independent porous supports placed outside the membrane tube through coating or other methods. This "external catalysis, internal permeation" separation design, while achieving a certain degree of coupling between reaction and separation, also introduces significant mass transfer resistance, additional bed pressure drop, and potential interfacial contact thermal resistance problems. More importantly, it fails to fully utilize the potential catalytic support function of the membrane material itself, resulting in a complex reactor structure, reduced volumetric efficiency, and the need for long-range diffusion between reactants and permeated hydrogen across the membrane wall to reach their respective reaction and permeation zones, thus limiting kinetic efficiency. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a tubular nickel-iron alloy membrane and a method for preparing and loading a catalyst layer, which solves the problems of low conversion rate and hydrogen permeation of traditional dense and smooth metal membranes for methane water vapor reforming, as well as the difficulty and easy detachment of catalysts on the surface of traditional dense and smooth metal membranes.
[0005] The technical solution adopted in this invention is as follows: This invention provides a method for preparing a tubular nickel-iron alloy film, comprising: Polymethyl methacrylate was dissolved in N-methyl-2-pyrrolidone and mechanically stirred at 60℃~80℃. Ni powder and Fe powder were then added and stirred to disperse the mixture evenly to obtain a membrane solution. The solution was then extruded through a multi-channel system, straightened, and sintered to form a dense alloy membrane tube with internal channels. In the Fe powder and Ni powder, the Fe powder accounts for 20wt.%-40wt.%, and the mass ratio of Fe powder to Ni powder is 1 / 4 to 2 / 3; The particle size of both Fe powder and Ni powder is 1μm~10μm; The inner surface of the dense alloy film tube is etched using a surface wet chemical etching method to form a porous mesh structure on the inner surface, thereby obtaining a tubular nickel-iron alloy film with a porous inner surface.
[0006] As a preferred technical solution: The etching of the inner surface of the channel within the alloy film tube using a wet chemical etching method includes: The two ends of the dense alloy film tube are connected to the peristaltic pump pipeline, so that the acid etching solution circulates and peristalts in the channel to etch the inner surface of the channel.
[0007] The acid etching solution includes one of hydrochloric acid solution, nitric acid solution, and sulfuric acid solution, with a concentration of 20 mol.
[0008] The ratio of Ni-Fe powder, polymethyl methacrylate solution, and N-methyl-2-pyrrolidone is 7.2:0.7:2.1.
[0009] The sintering process includes: raising the temperature from room temperature to 500°C at a rate of 3°C / min in an air atmosphere and holding it at that temperature for a period of time; then raising the temperature to 1300°C at a rate of 3°C / min in a hydrogen atmosphere to complete the sintering.
[0010] The present invention also provides a tubular nickel-iron alloy film prepared according to the preparation method described above.
[0011] The present invention also provides a method for supporting a catalyst layer according to the aforementioned tubular nickel-iron alloy film, comprising: Polymethyl methacrylate, N-methyl-2-pyrrolidone and carrier powder were ball-milled and mixed to form a slurry; The tubular nickel-iron alloy film is connected to both ends of a peristaltic pump pipeline, so that the slurry circulates and peristalts in the channel, loads the inner wall of the channel after surface reconstruction, and then undergoes high-temperature sintering to form a precursor tube. Connect both ends of the precursor tube to the peristaltic pump pipeline, so that the catalyst solution circulates and peristalts in the channel, loading the inner wall of the precursor tube, and obtaining a tubular alloy film with a catalyst layer loaded on the inner wall of the channel. The support is one of Al2O3, CeO2, ZrO2, and MgO; The high-temperature sintering process includes: raising the temperature from room temperature to 500°C at a rate of 2.5°C / min in air atmosphere and holding it for 60-100 min, and then raising the temperature to 700°C at a rate of 2°C / min in hydrogen atmosphere and holding it for 180-240 min.
[0012] The catalyst solution is one or more of nickel nitrate, ferric nitrate, lanthanum nitrate, manganese nitrate, copper nitrate, and cobalt nitrate.
[0013] The carrier accounts for 30 wt.%-50 wt.% of the slurry.
[0014] The present invention also provides a tubular alloy membrane with a supported catalyst layer prepared according to the method.
[0015] The technical solution of the present invention can achieve at least some of the following beneficial effects: This invention utilizes the selective etching characteristics of the Ni-Fe alloy phase to achieve the controllable construction of a porous structure on the inner surface of a tubular dense metal membrane, providing a reliable foundation for directly constructing a highly adhesive, high specific surface area catalytic layer on the inner surface of a tubular dense metal membrane. The resulting membrane material possesses high hydrogen permeation selectivity, excellent catalytic activity, and structural stability, making it particularly suitable for integrated membrane catalysis processes such as methane reforming and dehydrogenation. This invention improves reactor design, enhances mass / heat transfer efficiency, and fully leverages the theoretical advantages of membrane catalytic reactors. Specific advantages include: 1. This invention, through chemical etching reconstruction, imparts a controllable porous structure to the inner surface of the membrane tube. Addressing the challenge that single-metal (pure Ni or pure Fe) films typically undergo uniform corrosion in acid, making it difficult to form a stable porous structure, this invention creatively utilizes the differences in electrochemical activity caused by compositional variations in Ni-Fe alloys. Controllable wet chemical etching selectively and preferentially dissolves specific phases or grain boundary regions. This selective etching can construct a three-dimensional interconnected porous network structure in situ on the inner surface of the membrane tube, while the outer surface remains dense due to controllable etching conditions or compositional gradients. The resulting tubular nickel-iron alloy film perfectly achieves a clever combination of "inner surface porosity" and "outer surface densification."
[0016] Both Ni and Fe are known hydrogen-permeable metals, and their alloying can maintain excellent selective hydrogen permeation performance while ensuring the mechanical strength of the material. Furthermore, due to their similar melting points (Ni: 1455℃, Fe: 1538℃), the atoms of both metals diffuse sufficiently during high-temperature co-sintering, easily forming a uniform, densely grained solid solution alloy phase. This avoids uneven sintering, porosity, or defects caused by excessive melting point differences. Therefore, based on the synergy of these two components, a high-strength, highly hydrogen-permeable, uniform, and dense membrane can be obtained, providing a stable and reliable self-supporting dense separation layer for subsequent membrane reactor construction. Experimental verification shows that, in application, the tubular nickel-iron alloy membrane of this invention, compared with traditional dense alloy membrane tubes, significantly improves the conversion rate and hydrogen permeation of methane water vapor reforming without affecting the purity of the recovered hydrogen.
[0017] Meanwhile, the Ni-Fe alloy itself exhibits certain catalytic activity for many hydrogenation / dehydrogenation reactions, and its porous internal structure further exposes more active sites. The resulting porous network structure possesses extremely high specific surface area and abundant microscopic anchoring points, thereby improving the core bottleneck of difficult catalyst loading and easy detachment on traditional smooth metal film surfaces.
[0018] 2. This invention employs a two-step loading strategy: first, the support layer is loaded, then the active component is loaded. The first step involves loading a high-temperature stable oxide support, such as Al2O3 or CeO2, into a slurry and sintering it at high temperature. This anchors the support firmly onto the porous alloy framework, forming a robust intermediate layer. This step pre-burns away organic matter in the slurry at 500°C, preventing contamination or coverage of active sites by organic matter during subsequent loading of the active component. The second step involves loading catalytically active components, such as Ni, Co, and Cu, through an impregnation method. Depending on the target catalytic reaction (e.g., methane dry reforming, water-gas shift reaction), single or multiple metal salt solutions can be flexibly selected, allowing for customized catalyst composition.
[0019] Other features and advantages of the invention will be set forth in the following description or may be learned by practicing the invention. Attached Figure Description
[0020] Figure 1 This is a flowchart of the tubular nickel-iron alloy film preparation method according to an embodiment of the present invention.
[0021] Figure 2 This is a cross-sectional SEM image of the four-channel dense alloy film prepared in Comparative Example 1 of this invention.
[0022] Figure 3 This is a SEM image of the porous inner surface of the tubular nickel-iron alloy film prepared under different Fe-Ni ratios in Example 1 of the present invention.
[0023] Figure 4This is a flowchart of the method for supporting a catalyst layer on a tubular nickel-iron alloy film according to an embodiment of the present invention.
[0024] Figure 5 SEM image of the inner surface of the alloy film with the supported catalyst layer prepared in Example 2 of this invention. Detailed Implementation
[0025] The specific embodiments of the present invention are described below with reference to the accompanying drawings.
[0026] See Figure 1 This invention provides a method for preparing a tubular nickel-iron alloy film, comprising: S101. Polymethyl methacrylate (PMMA) is dissolved in N-methyl-2-pyrrolidone (NMP), mechanically stirred at 60°C, and then Ni powder and Fe powder are added. The mixture is stirred and dispersed evenly to obtain a membrane solution. The solution is then extruded through a multi-channel system, straightened, and sintered to form a dense alloy membrane tube with internal channels.
[0027] In one specific embodiment, the ratio of Ni-Fe powder, polymethyl methacrylate solution, and N-methyl-2-pyrrolidone is 7.2:0.7:2.1.
[0028] In one specific embodiment, the sintering process includes: raising the temperature from room temperature to 500°C at a rate of 3°C / min in an air atmosphere and holding it at that temperature for a period of time; and then raising the temperature to 1300°C at a rate of 3°C / min in a hydrogen atmosphere to complete the sintering.
[0029] S102. The inner surface of the channel of the dense alloy film tube is etched by surface wet chemical etching to form a porous mesh structure on the inner surface, thereby obtaining a tubular nickel-iron alloy film with a porous inner surface.
[0030] In one specific embodiment, the dense alloy membrane tube has a four-channel structure with a wall thickness of approximately 50 micrometers. Figure 2 As shown, the inner and outer surfaces of this dense alloy membrane tube exhibit a highly smooth, low specific surface area dense metallic state. This smoothness actually greatly limits the effective and stable loading of subsequent catalytic functional layers.
[0031] See Figure 3 The present invention reconstructs the inner surface of the channel of the dense alloy film tube by surface wet chemical etching, and the porous mesh structure is formed on the inner surface, which includes abundant micro protrusions, depressions and pores. Figure 3The image shows the internal surface morphology for different Ni / Fe ratios. From top to bottom, the Fe powder ratios are 20 wt.%, 30 wt.%, and 40 wt.%, while the Ni powder ratios are 80 wt.%, 70 wt.%, and 60 wt.%. It can be seen that the higher the Fe ratio, the more developed the porous structure is after etching. Therefore, the pore size, pore density, and etching depth of the porous structure can be adjusted by regulating the Ni / Fe ratio.
[0032] As a preferred embodiment, the Fe powder accounts for 20wt.%-40wt.% of the Fe powder and the mass ratio of Fe powder to Ni powder is 1 / 4 to 2 / 3.
[0033] As a preferred embodiment, the particle size of both Fe powder and Ni powder is 1μm to 10μm, and preferably 1μm.
[0034] As a preferred method, the etching of the inner surface of the channel in the alloy film tube by surface wet chemical etching includes: connecting both ends of the dense alloy film tube to a peristaltic pump pipeline, so that the acid etching solution circulates and peristalts in the channel to etch the inner surface of the channel.
[0035] The acid etching solution preferably includes one of hydrochloric acid solution, nitric acid solution, and sulfuric acid solution, and the solution concentration is preferably 20 mol.
[0036] The depth of surface reconstruction can be further adjusted by changing the etching time. As a preferred method, the etching time is 5-10 min and the peristaltic flow rate is 2 mL / min.
[0037] See Figure 4 The present invention also provides a method for supporting a catalyst layer using the aforementioned tubular nickel-iron alloy film, comprising: S201. Polymethyl methacrylate, N-methyl-2-pyrrolidone and carrier powder are mixed and stirred in a planetary ball mill to form a carrier slurry; S202. Connect both ends of the tubular nickel-iron alloy membrane to the peristaltic pump pipeline, so that when the carrier slurry circulates and peristalts in the tubular nickel-iron alloy membrane channel, it is loaded on the inner wall of the channel after surface reconstruction. Then, high-temperature sintering treatment is performed to further anchor the carrier layer and prevent it from falling off, forming a structurally stable precursor tube. S203. Connect both ends of the precursor tube to a peristaltic pump pipeline, so that the catalyst solution is loaded when circulating and peristaltic in the channel, to obtain a tubular alloy film with a catalyst layer loaded on the inner wall of the channel; the support is one of Al2O3, CeO2, ZrO2, and MgO; the high-temperature sintering treatment includes: raising the temperature from room temperature to 500℃ at a rate of 2.5℃ / min in air atmosphere and holding it for 60-100min, and then raising the temperature to 700℃ at a rate of 2℃ / min in hydrogen atmosphere and holding it for 180-240min.
[0038] As a preferred embodiment, the carrier accounts for 30 wt.%-50 wt.% of the slurry.
[0039] As a preferred embodiment, the ratio of polymethyl methacrylate solution to N-methyl-2-pyrrolidone in the carrier slurry is 1:8.
[0040] As a preferred method, the circulation peristalsis time is 10-20 min or 15-25 min, and the peristalsis flow rate is 1-2 mL / min.
[0041] The loading amounts of both the support layer and the catalytic active layer can be precisely controlled by adjusting the peristaltic cycle time or the number of repetitions. Longer impregnation times and more repetitions result in a larger loading amount, thereby optimizing the catalytic layer thickness and active site density, providing customized solutions for different reaction kinetic requirements. Depending on the application requirements of the subsequent dehydrogenation reaction, the catalyst solution can be one or more of nickel nitrate, iron nitrate, lanthanum nitrate, manganese nitrate, copper nitrate, and cobalt nitrate.
[0042] The inner surface structure of the alloy film with the prepared supported catalyst layer is shown in [reference]. Figure 5 Because the inner surface of the tubular nickel-iron alloy film is reconstructed with porosity, it possesses abundant microscopic protrusions, depressions, and pores, significantly increasing the contact area and bonding sites between the catalyst layer and the substrate. This allows for a strong mechanical interlocking effect with the support slurry or catalyst precursor, which is beneficial for catalyst layer anchoring and thus helps form highly active catalytic centers. Simultaneously, this structure effectively prevents the catalyst coating from peeling off and detaching under thermal stress, fluid shear force, or reaction vibration.
[0043] The effectiveness of the technical solution of this application is further illustrated below with specific embodiments and comparative examples.
[0044] Comparative Example 1 The method for preparing the dense alloy membrane tube in this comparative example includes: 8g of organic polymer polymethyl methacrylate, 22g of N-methyl-2-pyrrolidone, 14g of Fe powder with a particle size of 1μm and 56g of Ni powder with a particle size of 1μm were weighed and stirred at 60℃ for 24 h. The mixture was then spun into a film, straightened, and heated from room temperature to 500℃ at a rate of 3℃ / min in air atmosphere and held at that temperature for a period of time. Finally, it was heated to 1300℃ at a rate of 3℃ / min in hydrogen atmosphere to complete sintering and obtain a dense alloy membrane tube A1.
[0045] Following the above process flow, under the same process conditions, by changing the amount of Fe powder and Ni powder added, dense alloy membrane tubes A2 and A3 were prepared. Specifically: When preparing the dense alloy membrane tube A2, 21g of Fe powder with a particle size of 1μm and 49g of Ni powder with a particle size of 1μm were added.
[0046] When preparing the dense alloy membrane tube A3, 28g of Fe powder with a particle size of 1μm and 42g of Ni powder with a particle size of 1μm were added.
[0047] Example 1 This embodiment provides a method for preparing a tubular nickel-iron alloy film, which involves reconstructing the inner surface of the dense alloy film tubes A1, A2, and A3 obtained in Comparative Example 1. The method includes: connecting both ends of the dense alloy film tubes to a peristaltic pump pipeline, circulating a 20 mol.% acid etching solution within the channel to etch the inner surface of the channel, forming a porous mesh structure on the inner surface, and obtaining a tubular nickel-iron alloy film with a porous inner surface. The peristaltic flow rate is 2 mL / min.
[0048] Following the above process flow, under the same other process conditions, by adjusting the type of etching solution and etching time, six sets of tubular nickel-iron alloy films M1 to M6 were obtained, specifically including: The dense alloy film tube A1 was etched with hydrochloric acid solution for 5 minutes to obtain the tubular nickel-iron alloy film M1.
[0049] The dense alloy film tube A1 was etched with nitric acid solution for 10 minutes to obtain the tubular nickel-iron alloy film M2.
[0050] The dense alloy film tube A2 was etched with sulfuric acid solution for 5 minutes to obtain the tubular nickel-iron alloy film M3.
[0051] The dense alloy film tube A2 was etched with nitric acid solution for 10 minutes to obtain the tubular nickel-iron alloy film M4.
[0052] The dense alloy film tube A3 was etched with hydrochloric acid solution for 5 minutes to obtain the tubular nickel-iron alloy film M5.
[0053] The dense alloy film tube A3 was etched with nitric acid solution for 10 minutes to obtain the tubular nickel-iron alloy film M6.
[0054] To verify the performance of the products prepared in Comparative Example 1 and Example 1, the following performance test experiments were conducted for comparison: Methane vapor reforming was performed using the dense alloy membrane tube A1 prepared in Comparative Example 1, including: The test was conducted at 800℃ with a CH4 flow rate of 5 ml / min and a water vapor flow rate of 25 ml / min. The conversion rate of methane reforming was 61.9%; the purity of the recovered hydrogen was 99.2%; and the hydrogen permeation rate was 5 mmol / m³. -2 s -1.
[0055] Methane vapor reforming was performed using the tubular nickel-iron alloy membrane M6 prepared in Example 1, including: The test was conducted at 800℃ with a CH4 flow rate of 5 ml / min and a water vapor flow rate of 25 ml / min. The conversion rate of methane reforming was 91.9%; the purity of the recovered hydrogen was 99.1%; and the hydrogen permeation was 8 mmol / m³. -2 s -1 .
[0056] As can be seen, the tubular nickel-iron alloy membrane with inner surface reconstruction in Example 1, compared with the dense alloy membrane tube without inner surface reconstruction in Comparative Example 1, significantly improves the conversion rate of methane water vapor reforming and the amount of hydrogen permeation without affecting the purity of recovered hydrogen.
[0057] Example 2 This embodiment provides a method for supporting a catalyst layer using a tubular nickel-iron alloy film prepared in Example 1, comprising: 2.1 Preparation of alloy film N1 with supported catalyst layer: (1) Weigh 6g of Al2O3 powder, 10g of organic polymer polymethyl methacrylate and 4g of N-methyl-2-pyrrolidone and stir them in a planetary ball mill for 5h to form a slurry; (2) Connect both ends of the tubular nickel-iron alloy membrane M1 to a peristaltic pump so that the slurry is loaded on the inner wall of the channel after surface reconstruction when it circulates and peristalses in the channel; the circulation and peristalsis time is 15 min, the peristalsis flow rate is 2 mL / min, the temperature is increased from room temperature to 500℃ at a rate of 2.5℃ / min in air atmosphere and held for 100 min, and then sintered at a rate of 2℃ / min to 700℃ in hydrogen atmosphere and held for 180 min to form the precursor tube; (3) Prepare a nickel nitrate solution and connect it to the precursor tube through a peristaltic pump so that the catalyst solution is loaded when circulating and peristaltic in the tube channel. The circulation and peristaltic time is 10 min, the peristaltic flow rate is 1 mL / min, the temperature is increased from room temperature to 500℃ at a rate of 2.5 ℃ / min under air atmosphere and held for 60 min, and then sintered at a rate of 2 ℃ / min under hydrogen atmosphere to 700℃ and held for 240 min to obtain the alloy film N1 with the catalyst layer loaded.
[0058] 2.2 Preparation of alloy film N2 with supported catalyst layer: (1) Weigh 10g of Al2O3 powder, 5g of organic polymer polymethyl methacrylate and 5g of N-methyl-2-pyrrolidone and stir them in a planetary ball mill for 5h to form a slurry; (2) Connect both ends of the tubular nickel-iron alloy membrane M2 to a peristaltic pump so that the slurry is loaded on the inner wall of the channel after surface reconstruction when it circulates and peristalses in the channel; the circulation and peristalsis time is 25 min, the peristalsis flow rate is 2 mL / min, the temperature is increased from room temperature to 500℃ at a rate of 2.5℃ / min in air atmosphere and held for 100 min, and then sintered at a rate of 2℃ / min to 700℃ in hydrogen atmosphere and held for 180 min to form the precursor tube; (3) Prepare ferric nitrate solution and connect it to the precursor tube through a peristaltic pump so that the catalyst solution is loaded when circulating and peristaltic in the tube channel; the circulation and peristaltic time is 20 min, the peristaltic flow rate is 1 mL / min, the temperature is increased from room temperature to 500℃ at a rate of 2.5 ℃ / min under air atmosphere and held for 60 min, and then sintered at a rate of 2 ℃ / min under hydrogen atmosphere to 700℃ and held for 240 min to obtain alloy film N2 with loaded catalyst layer.
[0059] 2.3 Preparation of alloy film N3 with supported catalyst layer: (1) Weigh 6g of CeO2 powder, 10g of organic polymer polymethyl methacrylate and 4g of N-methyl-2-pyrrolidone and stir them in a planetary ball mill for 5h to form a slurry; (2) Connect both ends of the tubular nickel-iron alloy membrane M3 to a peristaltic pump so that the slurry is loaded on the inner wall of the channel after surface reconstruction when it circulates and peristalses in the channel; the circulation and peristalsis time is 15 min, the peristalsis flow rate is 2 mL / min, the temperature is increased from room temperature to 500℃ at a rate of 2.5℃ / min in air atmosphere and held for 100 min, and then sintered at a rate of 2℃ / min to 700℃ in hydrogen atmosphere and held for 180 min to form the precursor tube; (3) Prepare a mixed catalyst solution of lanthanum nitrate, manganese nitrate and copper nitrate, and connect it to the precursor tube through a peristaltic pump so that the catalyst solution is loaded when circulating and peristaltic in the tube channel; the circulation and peristaltic time is 10 min, the peristaltic flow rate is 1 mL / min, the temperature is increased from room temperature to 500℃ at a rate of 2.5 ℃ / min under air atmosphere, and held for 60 min, and then sintered at a rate of 2 ℃ / min under hydrogen atmosphere to 700℃ and held for 240 min to obtain the alloy film N3 with the catalyst layer loaded.
[0060] 2.4 Preparation of alloy film N4 with supported catalyst layer: (1) Weigh 10g ZrO2 powder, 5g organic polymer polymethyl methacrylate and 5g N-methyl-2-pyrrolidone and stir them in a planetary ball mill for 5h to form a slurry; (2) Connect both ends of the tubular nickel-iron alloy membrane M4 to a peristaltic pump so that the slurry is loaded on the inner wall of the channel after surface reconstruction when it circulates and peristalses in the channel; the circulation and peristalsis time is 20 min, the peristalsis flow rate is 2 mL / min, the temperature is increased from room temperature to 500℃ at a rate of 2.5℃ / min in air atmosphere and held for 100 min, and then sintered at a rate of 2℃ / min to 700℃ in hydrogen atmosphere and held for 180 min to form the precursor tube; (3) Prepare a mixed catalyst solution of nickel nitrate and cobalt nitrate, and connect it to the precursor tube through a peristaltic pump so that the catalyst solution is loaded when circulating and peristaltic in the tube channel. The circulation and peristaltic time is 15 min, the peristaltic flow rate is 1 mL / min, the temperature is increased from room temperature to 500℃ at a rate of 2.5 ℃ / min under air atmosphere, and held for 60 min. Then, the temperature is increased to 700℃ at a rate of 2 ℃ / min under hydrogen atmosphere and held for 240 min to complete the sintering and obtain the alloy film N4 with the catalyst layer loaded.
[0061] 2.5 Preparation of alloy film N5 with supported catalyst layer: (1) Weigh 10g of MgO powder, 5g of organic polymer polymethyl methacrylate and 5g of N-methyl-2-pyrrolidone and stir in a planetary ball mill for 5h to form a slurry: (2) Connect both ends of the tubular nickel-iron alloy membrane M5 to a peristaltic pump so that the slurry is loaded on the inner wall of the channel after surface reconstruction when it circulates and peristalses in the channel; the circulation and peristalsis time is 20 min, the peristalsis flow rate is 2 mL / min, the temperature is increased from room temperature to 500℃ at a rate of 2.5℃ / min in air atmosphere and held for 100 min, and then sintered at a rate of 2℃ / min to 700℃ in hydrogen atmosphere and held for 180 min to form the precursor tube; (3) Prepare a mixed catalyst solution of nickel nitrate and copper nitrate, and connect it to the precursor tube through a peristaltic pump so that the catalyst solution is loaded when circulating and peristaltic in the tube channel. The circulation and peristaltic time is 15 min, the peristaltic flow rate is 1 mL / min, the temperature is increased from room temperature to 500℃ at a rate of 2.5 ℃ / min under air atmosphere, and held for 60 min. Then, the temperature is increased to 700℃ at a rate of 2 ℃ / min under hydrogen atmosphere and held for 240 min to complete the sintering and obtain the alloy film N5 with the catalyst layer loaded.
[0062] 2.6 Preparation of alloy film N6 with supported catalyst layer: (1) Weigh 6g of CeO2 powder, 10g of organic polymer polymethyl methacrylate and 4g of N-methyl-2-pyrrolidone and stir them in a planetary ball mill for 5h to form a slurry; (2) Connect both ends of the tubular nickel-iron alloy membrane M6 to a peristaltic pump so that the slurry is loaded on the inner wall of the channel after surface reconstruction when it circulates and peristalses in the channel; the circulation and peristalsis time is 15 min, the peristalsis flow rate is 2 mL / min, the temperature is increased from room temperature to 500℃ at a rate of 2.5℃ / min in air atmosphere and held for 100 min, and then sintered at a rate of 2℃ / min to 700℃ in hydrogen atmosphere and held for 180 min to form the precursor tube; (3) Prepare a mixed catalyst solution of nickel nitrate, lanthanum nitrate and copper nitrate, and connect it to the precursor tube through a peristaltic pump so that the catalyst solution is loaded when circulating and peristaltic in the tube channel; the circulation and peristaltic time is 10 min, the peristaltic flow rate is 1 mL / min, the temperature is increased from room temperature to 500℃ at a rate of 2.5 ℃ / min under air atmosphere, and held for 60 min, and then sintered at a rate of 2 ℃ / min under hydrogen atmosphere to 700℃ and held for 240 min to obtain the alloy film N6 with the catalyst layer loaded.
[0063] Example 3 This embodiment provides an application of the alloy film with the supported catalyst layer prepared in Example 2 for various dehydrogenation reactions, specifically including: 3.1 Methane wet reforming: Methane steam reforming was performed using an alloy membrane N1 with a supported catalyst layer. The CH4 flow rate was 15 ml / min, the water vapor flow rate was 25 ml / min, and the test was conducted at 800 °C. The conversion rate of methane steam reforming was 95.1%; the purity of the recovered hydrogen was 99.1%; and the hydrogen permeation was 12 mmol / m³. -2 s -1 .
[0064] 3.2 Dry reforming of methane: Dry reforming of methane was performed using an alloy membrane with a supported catalyst layer and N2. The CH4 flow rate was 15 ml / min, the CO2 flow rate was 25 ml / min, and the test was conducted at 800 °C. The methane conversion rate was 96.7%; the recovered hydrogen purity was 99.5%; and the hydrogen permeation was 14 mmol / m³. -2 s -1 .
[0065] 3.3 Water vapor shift: A water-vapor shift reaction was performed using an alloy membrane N3 with a supported catalyst layer. The CO flow rate was 15 ml / min, the water vapor flow rate was 25 ml / min, and the test was conducted at 800 °C. The CO conversion rate was 92.2%; the recovered hydrogen purity was 99.0%; and the hydrogen permeation rate was 11 mmol / m³. -2 s -1 .
[0066] 3.4 Toluene reforming reaction: Toluene reforming was performed using an alloy membrane N4 with a supported catalyst layer. The toluene flow rate was 0.6 μL / min, the water vapor flow rate was 3 μL / min, and the test was conducted at 800 °C. The toluene conversion rate was 91.5%; the recovered hydrogen purity was 99.2%; and the hydrogen permeation was 1 mmol / m³. -2 s -1 .
[0067] 3.5 Tetrahydronaphthalene reforming reaction: Tetrahydronaphthalene reforming was performed using an alloy membrane N5 with a supported catalyst layer. The tetrahydronaphthalene flow rate was 0.5 μL / min, the water vapor flow rate was 3 μL / min, and the test was conducted at 800 °C. The conversion rate of tetrahydronaphthalene was 90.3%; the purity of the recovered hydrogen was 99.0%; and the hydrogen permeation was 0.8 mmol / m³. -2 s -1 .
[0068] 3.6 Methanol dehydrogenation reaction: Methanol dehydrogenation was performed using an alloy membrane N6 with a supported catalyst layer. The methanol flow rate was 5 μL / min, and the test was conducted at 800 °C. The methanol conversion rate was 91.5%; the recovered hydrogen purity was 99.2%; and the hydrogen permeation was 2 mmol / m³. -2 s -1 .
[0069] In summary, this invention, based on the porous modification of the inner surface of the dense tubular membrane channel, significantly increases the active specific surface area for hydrogen dissociation and adsorption, thereby substantially improving the hydrogen permeation flux. Simultaneously, the density of the outer surface and the membrane body strictly ensures ultra-high hydrogen separation purity. This invention employs a two-step loading strategy: first, the carrier layer is removed, followed by the active component. Organic matter in the slurry is burned off first, preventing organic matter contamination or coverage of active sites during subsequent active component loading. Then, the catalytic active component is loaded via impregnation. The type of catalytic active component can be selected according to the requirements of the target catalytic reaction (such as methane dry reforming, water-gas shift reaction, etc.), offering high flexibility.
[0070] It will be understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for producing a tubular ferronickel alloy film, characterized by, include: Polymethyl methacrylate was dissolved in N-methyl-2-pyrrolidone and mechanically stirred at 60℃~80℃. Ni powder and Fe powder were then added and stirred to disperse the mixture evenly to obtain a membrane solution. The solution was then extruded through a multi-channel system, straightened, and sintered to form a dense alloy membrane tube with internal channels. In the Fe powder and Ni powder, the Fe powder accounts for 20wt.%-40wt.%, and the mass ratio of Fe powder to Ni powder is 1 / 4 to 2 / 3; The particle size of both Fe powder and Ni powder is 1μm~10μm; The inner surface of the dense alloy film tube is etched using a surface wet chemical etching method to form a porous mesh structure on the inner surface, thereby obtaining a tubular nickel-iron alloy film with a porous inner surface.
2. The preparation method according to claim 1, characterized in that, The etching of the inner surface of the channel within the alloy film tube using a wet chemical etching method includes: The two ends of the dense alloy film tube are connected to the peristaltic pump pipeline, so that the acid etching solution circulates and peristalts in the channel to etch the inner surface of the channel.
3. The preparation method according to claim 2, characterized in that, The acid etching solution includes one of hydrochloric acid solution, nitric acid solution, and sulfuric acid solution, with a concentration of 20 mol.
4. The preparation method according to claim 1, characterized in that, The ratio of Ni-Fe powder, polymethyl methacrylate solution, and N-methyl-2-pyrrolidone is 7.2:0.7:2.
1.
5. The preparation method according to claim 1, characterized in that, The sintering process includes: raising the temperature from room temperature to 500°C at a rate of 3°C / min in an air atmosphere and holding it at that temperature for a period of time; then raising the temperature to 1300°C at a rate of 3°C / min in a hydrogen atmosphere to complete the sintering.
6. A tubular nickel-iron alloy film prepared by the preparation method according to any one of claims 1-5.
7. A method for supporting a catalyst layer on a tubular nickel-iron alloy film according to claim 6, characterized in that, include: Polymethyl methacrylate, N-methyl-2-pyrrolidone and carrier powder were ball-milled and mixed to form a slurry; The tubular nickel-iron alloy film is connected to both ends of a peristaltic pump pipeline, so that the slurry circulates and peristalts in the channel, loads the inner wall of the channel after surface reconstruction, and then undergoes high-temperature sintering to form a precursor tube. Connect both ends of the precursor tube to the peristaltic pump pipeline, so that the catalyst solution circulates and peristalts in the channel, loading the inner wall of the precursor tube, and obtaining a tubular alloy film with a catalyst layer loaded on the inner wall of the channel. The support is one of Al2O3, CeO2, ZrO2, and MgO; The high-temperature sintering process includes: raising the temperature from room temperature to 500°C at a rate of 2.5°C / min in air atmosphere and holding it for 60-100 min, and then raising the temperature to 700°C at a rate of 2°C / min in hydrogen atmosphere and holding it for 180-240 min.
8. The method according to claim 7, characterized in that, The catalyst solution is one or more of nickel nitrate, ferric nitrate, lanthanum nitrate, manganese nitrate, copper nitrate, and cobalt nitrate.
9. The method according to claim 7, characterized in that, The carrier accounts for 30 wt.%-50 wt.% of the slurry.
10. A tubular alloy membrane with a supported catalyst layer prepared by the method according to claim 7.