Hollow fiber membrane, method for producing the same, and use thereof

Abstract

This invention relates to the field of membrane separation technology, specifically disclosing a hollow fiber membrane, its preparation method, and its applications. The hollow fiber membrane comprises an inner layer, a middle layer, and an outer layer. This invention adjusts the ratio of ceramic powder, inorganic powder, polymer, and solvent in the casting solution of the inner, middle, and outer layers, and limits the specific substances of the ceramic and inorganic powders in the hollow fiber membrane. This allows the porous structure of the prepared hollow fiber membrane to extend from the inner layer to the middle layer, forming through channels conducive to gas transport. While ensuring the compactness of the hollow fiber membrane, it also reduces gas diffusion resistance and increases the active sites for electrode reactions, significantly improving the hydrogen separation performance of the hollow fiber membrane under medium and low temperature conditions. Furthermore, the prepared hollow fiber membrane can also achieve the separation and recovery of low-concentration hydrogen.

Description

Technical Field

[0001] This invention relates to the field of membrane separation technology, and in particular to a hollow fiber membrane, its preparation method, and its application. Background Technology

[0002] Hydrogen energy, as a crucial component of building a low-carbon energy system, relies on key technologies such as efficient and low-carbon hydrogen production and purification for its large-scale development. Currently, hydrogen sources are still mainly fossil fuels and industrial by-products, with a significant proportion coming from coal-to-hydrogen, natural gas-to-hydrogen, and by-products from chemical, petrochemical, and metallurgical industries. Hydrogen obtained from these processes typically contains impurities such as CO, CO2, and N2, and its purity is insufficient to directly meet the requirements of fuel cells, fine chemicals, and the electronics industry, necessitating further separation and purification. Existing hydrogen separation and purification technologies each have limitations. For example, pressure swing adsorption (PSA) technology suffers from high energy consumption and significant equipment investment in practical applications; while metal membrane separation technology offers high separation accuracy, its material costs are high, and its ability to recover low-concentration hydrogen is limited. Therefore, developing efficient, economical hydrogen separation technologies applicable to various operating conditions is of great significance.

[0003] Hollow fiber membranes have attracted widespread attention in the field of hydrogen separation due to their structural advantages such as large specific surface area, short mass transfer path, and ease of modular integration. However, existing hollow fiber membranes for hydrogen separation still have certain shortcomings: on the one hand, the chemical and structural stability of some membrane materials under complex atmospheres and long-term operating conditions needs to be improved, as they are prone to membrane structure degradation and separation performance decline, affecting their service life; on the other hand, most membrane systems need to operate at high temperatures, making it difficult to achieve efficient separation in the medium and low temperature range, which not only increases system energy consumption but also places higher demands on the heat resistance of equipment, thus limiting their application in actual industrial hydrogen purification processes. Therefore, developing a hollow fiber membrane with high structural stability, long service life, and the ability to achieve efficient hydrogen separation under medium and low temperature conditions, along with its controllable preparation method, is of significant practical importance and application prospects for overcoming existing technological limitations and meeting the actual needs of industrial hydrogen purification. Summary of the Invention

[0004] In view of this, the present invention provides a hollow fiber membrane, its preparation method and application.

[0005] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: This invention provides a hollow fiber membrane, comprising an inner layer, a middle layer, and an outer layer; Based on the total mass of the raw materials of the inner layer as 100%, it includes the following raw material components by mass percentage: 40%~45% inorganic powder, 3%~5% ceramic powder, 10%~15% polymer, 1%~2% pore-forming agent, and the balance being solvent; Based on the total mass of the raw materials in the intermediate layer as 100%, it includes the following raw material components by mass percentage: 35%~40% inorganic powder, 20%~25% ceramic powder, 5%~8% polymer, and the remainder is solvent; Based on the total mass of the raw materials of the outer layer as 100%, it includes the following raw material components by mass percentage: ceramic powder 60%~65%, inorganic powder 0.5%~2%, polymer 5%~8%, and the balance being solvent; The ceramic powder includes Ba （1.01~1.1） Ce 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ The inorganic powder includes transition metal oxides.

[0006] Compared to existing technologies, this invention constructs a hollow fiber membrane structure with functional zones by controlling the composition and ratio of the casting solutions for the inner, middle, and outer layers: The inner layer of the hollow fiber membrane is a porous metal current-collecting layer, which collects current and its high porosity reduces gas diffusion resistance; the middle layer is an anode layer, providing reactive sites; and the outer layer is a dense electrolyte layer, enabling proton conduction. Through the synergistic effect of these three layers, stable separation and efficient recovery of low-concentration hydrogen under medium- and low-temperature conditions are achieved.

[0007] During their research, the inventors discovered that limiting the Ba content in the ceramic powder further improves the compactness of the hollow fiber membrane. Furthermore, excess Ba can enhance proton conductivity by regulating lattice defects, thereby improving the hollow fiber membrane's ability to separate hydrogen. This invention selects transition metal oxides as the inorganic powder, which, after reduction, forms a highly electronically conductive metal that can effectively collect and transmit current, simplifying the process and significantly reducing ohmic impedance, further enhancing the hollow fiber membrane's ability to separate hydrogen.

[0008] The hollow fiber membrane provided by this invention has a porous structure that runs through the membrane wall after spinning. The pores extend from the inner layer to the middle layer, forming a through channel that facilitates gas transport. While ensuring the compactness of the electrolyte layer, it also reduces the gas diffusion resistance and increases the active sites of the electrode reaction, which significantly improves the stability of the hollow fiber membrane when separating hydrogen under medium and low temperature conditions. Furthermore, the hollow fiber membrane can also achieve the separation and recovery of low-concentration hydrogen.

[0009] Preferably, the thickness ratio of the inner layer, the middle layer and the outer layer is (2.7~3):(4.1~4.3):1.

[0010] More preferably, the thickness ratio of the inner layer, the middle layer and the outer layer is 2.85:4.29:1.

[0011] More preferably, the ceramic powder is Ba. 1.05 Ce 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ .

[0012] Preferably, the hollow fiber membrane has a wall thickness of 50~500μm and an inner diameter of 300~1100μm.

[0013] More preferably, the hollow fiber membrane has a wall thickness of 400~500μm and an inner diameter of 700~1100μm.

[0014] Preferably, the inorganic powder includes nickel oxide.

[0015] This invention selects nickel oxide as an inorganic powder, which forms a highly electronically conductive metallic nickel layer after reduction. This layer can effectively collect and transmit current, significantly reduce ohmic impedance, and improve the hydrogen separation capability of hollow fiber membranes.

[0016] Preferably, the particle size of the inorganic powder is 50~100μm.

[0017] Preferably, the particle size of the ceramic powder is ≤75μm.

[0018] Preferably, the method for preparing the ceramic powder includes the following steps: According to the stoichiometric ratio, barium source, cerium source, zirconium source, yttrium source and ytterbium source are mixed evenly, and then a solid-phase reaction is carried out at 900~1100℃ to obtain the ceramic powder.

[0019] More preferably, the barium source includes barium carbonate.

[0020] More preferably, the cerium source includes cerium oxide.

[0021] More preferably, the zirconium source includes zirconium oxide.

[0022] More preferably, the yttrium source includes yttrium oxide.

[0023] More preferably, the ytterbium source includes ytterbium trioxide.

[0024] For example, the mixing can be ball milling for 8 to 24 hours.

[0025] More preferably, the solid-phase reaction takes 5 to 10 hours.

[0026] Preferably, the polymer comprises at least one of polysulfone or polyvinylpyrrolidone.

[0027] Preferably, the solvent includes at least one of N,N-dimethylformamide or N-methylpyrrolidone.

[0028] Preferably, the pore-forming agent comprises carbon-based particles.

[0029] More preferably, the pore-forming agent comprises graphite.

[0030] More preferably, the particle size of the pore-forming agent is 325~5000 mesh.

[0031] Preferably, the outer surface of the hollow fiber membrane may further include a cathode layer and a cathode current collection layer in sequence.

[0032] More preferably, the thickness of the cathode layer is 10~50μm.

[0033] More preferably, based on the total mass of the cathode slurry as 100%, the cathode slurry used in the cathode layer comprises the following raw material components by mass percentage: 60%~80% electrode active material, 1%~10% binder, and the balance being alcohol solvent.

[0034] For example, the electrode active material includes at least one of nickel or nickel oxide.

[0035] For example, the adhesive includes at least one of ethyl cellulose or polyvinyl alcohol.

[0036] For example, the alcohol solvent includes at least one of terpineol or anhydrous ethanol.

[0037] More preferably, the thickness of the cathode current collecting layer is 10~20μm.

[0038] More preferably, based on the total mass of the conductive paste as 100%, the conductive paste used for the cathode current collection layer comprises the following raw material components by mass percentage: 60% to 80% conductive material, 1% to 10% binder, and the balance being alcohol solvent.

[0039] For example, the conductive material includes at least one of silver paste or nickel paste.

[0040] For example, the adhesive includes at least one of ethyl cellulose or polyvinyl alcohol.

[0041] For example, the alcohol solvent includes at least one of terpineol or anhydrous ethanol.

[0042] This invention provides a method for preparing the above-mentioned hollow fiber membrane, comprising the following steps: S1. Weigh each raw material according to the design ratio and prepare the inner layer casting solution, the middle layer casting solution and the outer layer casting solution respectively. S2. Vacuum degassing, co-spinning, and drying are performed on the inner layer casting solution, the middle layer casting solution, and the outer layer casting solution to obtain hollow fiber precursor. S3. The hollow fiber precursor is sintered at 1420~1460℃ to obtain a hollow fiber membrane.

[0043] The hollow fiber membrane preparation method provided by this invention uses co-spinning and co-sintering techniques to prepare a hollow fiber membrane with a radially interconnected porous channel structure, which significantly improves its stability under medium and low temperature conditions. At the same time, the hollow fiber membrane prepared by the above method is integrally formed, avoiding the problem of interlayer cracks. It has excellent proton conductivity and chemical stability at medium and low temperatures, and significantly improves the hydrogen separation capability of the hollow fiber membrane.

[0044] For example, in S2, the vacuum degassing can be carried out under a vacuum of 0.02 MPa, and the degassing time is no longer further limited, as long as the air bubbles in the casting solution are removed.

[0045] Vacuum degassing treatment helps reduce film defects caused by bubble expansion or rupture during co-spinning, thereby improving the continuity and integrity of the hollow fiber precursor structure.

[0046] Preferably, in S2, the co-spun yarn requires the use of an external coagulant and an internal coagulant.

[0047] More preferably, the external coagulant includes at least one of water, anhydrous ethanol, and N-methylpyrrolidone.

[0048] More preferably, the internal coagulant includes at least one of water, anhydrous ethanol, and N-methylpyrrolidone.

[0049] For example, both the external and internal coagulants are water, and their temperature can be 10~60℃.

[0050] Through the synergistic effect of external and internal coagulants, the solvent and non-solvent in each layer of casting solution are exchanged, inducing a phase transformation process, thereby forming a hollow fiber precursor with a multi-layer structure.

[0051] More preferably, in S2, the volumetric flow rate ratio of the inner layer casting liquid, the middle layer casting liquid, and the outer layer casting liquid is (1~2):(4~8):(1~2).

[0052] The present invention further defines the volumetric flow rate ratio of the inner layer casting solution, the middle layer casting solution, and the outer layer casting solution, which can precisely adjust the inner diameter of the hollow fiber membrane, the thickness of each functional layer, and the overall wall thickness, ensuring that the inner layer forms a high-porosity current collection layer, the middle layer forms a moderately porous anode functional layer, and the outer layer forms a highly dense electrolyte layer, thereby obtaining a hollow fiber membrane with stable structure and excellent performance.

[0053] More preferably, the volume flow ratio of the inner casting solution, the middle casting solution, the outer casting solution and the inner coagulant is (1~2):(4~8):(1~2):(2~4).

[0054] During the co-spinning process, the casting solution of each layer enters the coagulation bath through the air gap, and through the phase transformation between solvent and non-solvent, a hollow fiber precursor with a multi-layer structure is formed.

[0055] For example, in S2, the drying method can be natural drying or oven drying.

[0056] The drying process removes small amounts of residual external and internal coagulants from the surface and interior of the hollow fiber precursor, providing a structurally stable hollow fiber precursor for subsequent sintering processes.

[0057] Preferably, in S3, the sintering is carried out in an air atmosphere or an oxygen atmosphere.

[0058] Preferably, in step S3, the sintering time is 3 to 7 hours.

[0059] The preferred sintering temperature can remove polymers, pore-forming agents or other organic additives added to the hollow fiber membrane.

[0060] Preferably, in step S3, the temperature is increased to 1420~1460℃ at a rate of 0.5~5℃ / min.

[0061] In a further preferred embodiment, in S3, a programmed temperature rise method is used, with the temperature increased to 1420~1460℃ at a rate of 1~3℃ / min.

[0062] Preferably, in S3, after sintering, a programmed cooling method is used to cool the temperature to room temperature at a rate of 1~3℃ / min.

[0063] This invention provides the application of the above-mentioned hollow fiber membrane in hydrogen separation and recovery.

[0064] The hollow fiber membrane provided by this invention has a multi-layered integrated structure, good structural stability and electrochemical reaction adaptability, and can achieve selective transport and separation of hydrogen under medium and low temperature conditions, making it suitable for hydrogen separation and recovery. Attached Figure Description

[0065] Figure 1 A photograph of the hollow fiber membrane provided in Example 1. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0067] Unless otherwise specified, the embodiments and raw materials involved in this invention are all commercially available products, or can be prepared by referring to existing technical preparation methods.

[0068] Polysulfone: Model Udel® P-3500, purchased from Solvay Specialty Polymers, or a commercially available equivalent; Pore-forming agent: 325 mesh or 5000 mesh graphite powder, industrial grade, commercially available standard product; Silver paste: commercially available conductive silver paste (may contain terpineol as a diluent), purchased from Kunshan Hais Electronic Materials Co., Ltd.

[0069] The specific supplier and model of the above-mentioned raw materials do not affect the effect of the present invention, and can be replaced with commercially available equivalent products as needed.

[0070] Example 1 This embodiment provides a hollow fiber membrane with a wall thickness of 449.75 μm and an inner diameter of 1089.2 μm, comprising an inner layer, a middle layer, and an outer layer, with a thickness ratio of 2.85:4.29:1. The casting solution of the inner layer comprises 100% of the total mass of the raw materials, including the following raw material components by mass percentage: 40% inorganic powder, 5% ceramic powder, 15% polymer, 1% pore-forming agent, and the balance being solvent. The casting solution of the intermediate layer, with a total mass of 100%, includes the following raw material components by mass percentage: 35% inorganic powder, 25% ceramic powder, 5% polymer, and the remainder is solvent. The casting solution for the outer layer, based on a total mass of 100%, includes the following raw material components by mass percentage: ceramic powder 60%, inorganic powder 2%, polymer 5%, and the remainder being solvent; The method for preparing ceramic powder includes the following steps: Based on a molar ratio of barium carbonate, cerium oxide, zirconium oxide, yttrium oxide, and ytterbium trioxide of 1.05:0.7:0.1:0.1:0.1, barium carbonate, cerium oxide, zirconium oxide, yttrium oxide, and ytterbium trioxide were added to a ball mill jar, anhydrous ethanol was added as the dispersion medium, and zirconium oxide balls were used as the grinding medium. The mixture was ball-milled in a planetary ball mill for 12 hours to obtain a uniform slurry, which was then dried at 80°C for 18 hours to obtain a dried mixed powder. The dried mixed powder was sintered in air at 1100℃ for 5 hours, then naturally cooled and ball-milled again for 6 hours to obtain Ba ceramic powder with a particle size of 1~10μm. 1.05 Ce 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ ; The inorganic powder is nickel oxide with a particle size of 50~60μm; The polymer is polysulfone; The pore-forming agent is 325-mesh graphite; The solvent is N-methylpyrrolidone.

[0071] This embodiment provides a method for preparing the above-mentioned hollow fiber membrane, including the following steps: The components of the inner layer casting solution were mixed evenly and stirred at room temperature for 48 hours to obtain a uniform and stable inner layer casting solution; the preparation methods of the middle layer casting solution and the outer layer casting solution were the same as those of the inner layer casting solution. Under a vacuum pressure of 0.02 MPa, the inner layer casting solution, the middle layer casting solution, and the outer layer casting solution were degassed to remove air bubbles. The degassed casting solution was then loaded into syringes, while the inner coagulant was loaded into another syringe. Co-spinning was performed using a multi-channel hollow fiber spinneret with orifice diameters of 1.2 / 2.3 / 3.8 / 4.3 mm. The volumetric flow rates of the inner layer casting solution, the middle layer casting solution, the outer layer casting solution, and the inner coagulant were 1:4:2:4. Under the control of a high-pressure injection pump, the inner layer casting solution, the middle layer casting solution, the outer layer casting solution, and the inner coagulant were extruded. During the spinning process, the casting solution passed through an air gap of 10 cm and entered the outer coagulant to complete the phase transformation. Both the inner and outer coagulants were water. The resulting hollow fiber precursor was soaked in the outer coagulant for 24 hours before being removed. The obtained hollow fiber precursor was straightened and then naturally dried at room temperature to remove the coagulant residue on the surface and inside of the precursor. The hollow fiber precursor was sintered for 7 hours in air at a rate of 3℃ / min to 1420℃, and then cooled to room temperature at a rate of 3℃ / min to obtain a hollow fiber membrane.

[0072] Example 2 This embodiment provides a hollow fiber membrane with a wall thickness of 452.73 μm and an inner diameter of 1002.3 μm, comprising an inner layer, a middle layer, and an outer layer, with a thickness ratio of 2.8:4.3:1. The casting solution of the inner layer comprises 100% of the total mass of the raw materials, including the following raw material components by mass percentage: 45% inorganic powder, 3% ceramic powder, 12% polymer, 2% pore-forming agent, and the balance being solvent. The casting solution of the intermediate layer, with a total mass of 100%, includes the following raw material components by mass percentage: 37% inorganic powder, 20% ceramic powder, 7% polymer, and the remainder is solvent. The casting solution for the outer layer, based on a total mass of 100%, includes the following raw material components by mass percentage: ceramic powder 62%, inorganic powder 1%, polymer 7%, and the remainder is solvent; The method for preparing ceramic powder includes the following steps: Based on a molar ratio of barium carbonate, cerium oxide, zirconium oxide, yttrium oxide, and ytterbium trioxide of 1.07:0.7:0.1:0.1:0.1, barium carbonate, cerium oxide, zirconium oxide, yttrium oxide, and ytterbium trioxide were added to a ball mill jar, anhydrous ethanol was added as a dispersion medium, and zirconium oxide balls were used as the grinding medium. The mixture was ball-milled in a planetary ball mill for 12 hours to obtain a uniform slurry, which was then dried at 80°C for 18 hours to obtain a dried mixed powder. The dried mixed powder was sintered in air at 1000℃ for 8 hours, and then ball-milled again for 6 hours after natural cooling to obtain Ba ceramic powder with a particle size of 15~30μm. 1.07 Ce 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ ; The inorganic powder is nickel oxide with a particle size of 70~80μm; The polymer is polyvinylpyrrolidone; The pore-forming agent is 325-mesh graphite; The solvent is N-methylpyrrolidone.

[0073] This embodiment provides a method for preparing the above-mentioned hollow fiber membrane, including the following steps: The components of the inner layer casting solution were mixed evenly and stirred at room temperature for 48 hours to obtain a uniform and stable inner layer casting solution. The preparation methods of the middle layer casting solution and the outer layer casting solution were the same as those of the inner layer casting solution. Under a vacuum pressure of 0.02 MPa, the inner layer casting solution, the middle layer casting solution, and the outer layer casting solution were degassed to remove air bubbles. The degassed casting solutions were then loaded into syringes, while the inner coagulant was loaded into another syringe. Co-spinning was performed using a multi-channel hollow fiber spinneret with orifice diameters of 1.2 / 2.3 / 3.8 / 4.3 mm. The volumetric flow rates of the inner layer casting solution, the middle layer casting solution, the outer layer casting solution, and the inner coagulant were 1.5:6:1:2. Under the control of a high-pressure injection pump, the inner layer casting solution, the middle layer casting solution, the outer layer casting solution, and the inner coagulant were extruded. During the spinning process, the casting solution passed through an air gap of 10 cm and then entered the outer coagulant to complete the phase inversion. Both the inner and outer coagulants were water. The resulting hollow fiber precursor was soaked in the outer coagulant for 24 hours before being removed. The obtained hollow fiber precursor was straightened and then naturally dried at room temperature to remove the coagulant residue on the surface and inside of the precursor. The hollow fiber precursor was sintered for 4 hours in air at a rate of 1℃ / min to 1420℃, and then cooled to room temperature at a rate of 1℃ / min to obtain a hollow fiber membrane.

[0074] Example 3 This embodiment provides a hollow fiber membrane with a wall thickness of 443.6 μm and an inner diameter of 998.6 μm, comprising an inner layer, a middle layer and an outer layer, wherein the thickness ratio of the inner layer, the middle layer and the outer layer is 3:4.1:1; The casting solution of the inner layer comprises 100% of the total mass of the raw materials, including the following raw material components by mass percentage: inorganic powder 42%, ceramic powder 4%, polymer 10%, pore-forming agent 2%, and the balance being solvent. The casting solution of the intermediate layer, with a total mass of 100%, includes the following raw material components by mass percentage: 40% inorganic powder, 22% ceramic powder, 8% polymer, and the remainder is solvent. The casting solution for the outer layer, based on a total mass of 100%, includes the following raw material components by mass percentage: ceramic powder 65%, inorganic powder 0.5%, polymer 8%, and the remainder being solvent; The method for preparing ceramic powder includes the following steps: Based on a molar ratio of barium carbonate, cerium oxide, zirconium oxide, yttrium oxide, and ytterbium trioxide of 1.05:0.7:0.1:0.1:0.1, barium carbonate, cerium oxide, zirconium oxide, yttrium oxide, and ytterbium trioxide were added to a ball mill jar, anhydrous ethanol was added as the dispersion medium, and zirconium oxide balls were used as the grinding medium. The mixture was ball-milled in a planetary ball mill for 12 hours to obtain a uniform slurry, which was then dried at 80°C for 18 hours to obtain a dried mixed powder. The dried mixed powder was sintered in air at 1000℃ for 8 hours, then naturally cooled and ball-milled again for 6 hours to obtain Ba ceramic powder with a particle size of 40~60μm. 1.05 Ce 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ ; The inorganic powder is nickel oxide with a particle size of 80~100μm; The polymer is polyvinylpyrrolidone; The pore-forming agent is 5000-mesh graphite; The solvent is N-methylpyrrolidone.

[0075] This embodiment provides a method for preparing the above-mentioned hollow fiber membrane, including the following steps: The components of the inner layer casting solution were mixed evenly and stirred at room temperature for 48 hours to obtain a uniform and stable inner layer casting solution. The preparation methods of the middle layer casting solution and the outer layer casting solution were the same as those of the inner layer casting solution. Under a vacuum pressure of 0.02 MPa, the inner layer casting solution, the middle layer casting solution, and the outer layer casting solution were degassed to remove air bubbles. The degassed casting solutions were then loaded into syringes, while the inner coagulant was loaded into another syringe. Co-spinning was performed using a multi-channel hollow fiber spinneret with orifice diameters of 1.2 / 2.3 / 3.8 / 4.3 mm. The volumetric flow rates of the inner layer casting solution, the middle layer casting solution, the outer layer casting solution, and the inner coagulant were 2:8:1:4. Under the control of a high-pressure injection pump, the inner layer casting solution, the middle layer casting solution, the outer layer casting solution, and the inner coagulant were extruded. During the spinning process, the casting solution passed through an air gap of 10 cm and then entered the outer coagulant to complete the phase inversion. Both the inner and outer coagulants were water. The resulting hollow fiber precursor was soaked in the outer coagulant for 24 hours before being removed. The obtained hollow fiber precursor was straightened and then naturally dried at room temperature to remove the coagulant residue on the surface and inside of the precursor. The hollow fiber precursor was sintered for 4 hours in air at a rate of 2℃ / min to 1450℃, and then cooled to room temperature at a rate of 2℃ / min to obtain a hollow fiber membrane.

[0076] Comparative Example 1 This comparative example provides a hollow fiber membrane, which differs from Example 1 in that: The preparation method of ceramic powder includes the following steps: Based on a molar ratio of barium carbonate, cerium oxide, zirconium oxide, yttrium oxide, and ytterbium trioxide of 1:0.7:0.1:0.1:0.1, barium carbonate, cerium oxide, zirconium oxide, yttrium oxide, and ytterbium trioxide were added to a ball mill jar, anhydrous ethanol was added as the dispersion medium, and zirconium oxide balls were used as the grinding medium. The mixture was ball-milled in a planetary ball mill for 12 hours to obtain a uniform slurry, which was then dried at 80°C for 18 hours to obtain a dried mixed powder. The dried mixed powder was sintered in air at 1100℃ for 5 hours, and then ball-milled again for 6 hours after natural cooling to obtain BaCe ceramic powder with a particle size of 1~10μm. 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ ; The composition of other raw materials and the preparation process parameters are the same as in Example 1.

[0077] Comparative Example 2 This comparative example provides a hollow fiber membrane, which differs from Example 1 in that: the inner layer is omitted, and the resulting hollow fiber membrane includes an intermediate layer and an outer layer; the thickness ratio of the intermediate layer to the outer layer is 4.29:1, the wall thickness is 350.8 μm, and the inner diameter is 845.7 μm; The composition of other raw materials and the preparation process parameters are the same as in Example 1.

[0078] Example of effect A cathode layer and a cathode current collection layer were sequentially brushed onto the outer surface of the hollow fiber membranes provided in Example 1 and Comparative Examples 1-2, respectively, and were referred to as Application Example 1 and Comparative Application Examples 1-2. The cathode layer has a thickness of 20 μm. Based on the total mass of the cathode slurry (100%), the cathode slurry used in the cathode layer includes the following raw material components by mass percentage: 60% nickel oxide, 10% ethyl cellulose, and the balance being terpineol. The thickness of the cathode current collection layer is 10 μm. Based on the total mass of the conductive paste as 100%, the conductive paste used for the cathode current collection layer includes the following raw material components by mass percentage: 60% silver paste, 1% polyvinyl alcohol, and the balance being anhydrous ethanol.

[0079] The hollow fiber membrane provided in Application Example 1 is placed in the reactor shell, forming independent gas channels on both the inner and outer sides of the membrane. These channels are then connected to an external power source via conductive connectors, thus obtaining a microtubular proton ceramic electrochemical membrane reactor. The preparation process of the reactor using the hollow fiber membranes provided in Application Examples 1 and 2 is the same as in Application Example 1.

[0080] Hydrogen permeation performance and operational stability of the microtubular proton ceramic electrochemical membrane reactor fabricated with hollow fiber membranes provided in Application Example 1 and Comparative Application Examples 1-2 were tested. The hydrogen permeation flux of the reactor was measured under the conditions of a temperature of 250℃, an applied voltage of 2V, and a hydrogen gas integral of 30% in the feed gas.

[0081] Furthermore, during a 100-hour continuous stability test, the hydrogen permeation flux of the reactor was measured.

[0082] A microtubular proton-ceramic electrochemical membrane reactor was installed in an electrochemical testing apparatus. A hydrogen-containing mixed gas was introduced through the anode side, and a purge gas was introduced through the cathode side. During the test, the reactor operating temperature was maintained at 200–400 °C, the applied voltage was 2 V, and the total gas flow rate was 50 mL / min. -1 The hydrogen separation performance of the reactor was tested by changing the volume fraction of hydrogen in the feed gas on the anode side. The volume fraction of hydrogen in the feed gas was 5% and 10%, respectively, and the remaining components were inert gases. The hydrogen permeation flux of the reactor was measured under the conditions of a temperature of 250℃, an applied voltage of 2V, and a hydrogen gas fraction of 5% in the feed gas. The hydrogen permeation flux of the reactor was measured under the conditions of a temperature of 250℃, an applied voltage of 2V, and a hydrogen gas fraction of 10% in the feed gas. The specific test results are shown in Table 1: Table 1

[0083] As shown in Table 1, the hollow fiber membrane provided in this embodiment of the invention has stable electrochemical hydrogen pumping performance, good proton conduction ability and high operational stability under medium and low temperature conditions, and it also operates stably under different hydrogen feed concentrations, and has good electrochemical separation ability for low concentration hydrogen-containing gases.

[0084] As can be seen from the data in Application Example 1, when Ba is not excessively doped, the hollow fiber membrane’s ability to separate hydrogen with a volume fraction of 30% is significantly worse. Furthermore, under medium and low temperature and low hydrogen concentration conditions, the hydrogen permeation flux is also significantly reduced, which also proves the importance of excessive Ba doping in ceramic powder.

[0085] As can be seen from the data in Comparative Application Example 2, the hydrogen permeation flux of the hollow fiber membrane provided in Comparative Example 2 is significantly lower than that in Example 1 after 100 hours of continuous operation. Furthermore, the improvement in hydrogen permeation flux is limited under low hydrogen concentration conditions, and the overall data is significantly inferior to that of Example 1. This further demonstrates that the inner layer of the hollow fiber membrane in this embodiment of the invention does not merely serve as a support layer, but rather enhances electrode collection and gas diffusion through a high-porosity structure and a nickel network, thereby improving hydrogen separation performance under medium- and low-temperature, low-hydrogen-concentration environments.

[0086] The hollow fiber membranes provided in Examples 2 and 3 have comparable effects to the hollow fiber membrane provided in Example 1.

[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hollow fiber membrane, characterized in that, Includes inner layer, middle layer and outer layer; Based on the total mass of the raw materials of the inner layer as 100%, it includes the following raw material components by mass percentage: 40%~45% inorganic powder, 3%~5% ceramic powder, 10%~15% polymer, 1%~2% pore-forming agent, and the balance being solvent; Based on the total mass of the raw materials in the intermediate layer as 100%, it includes the following raw material components by mass percentage: 35%~40% inorganic powder, 20%~25% ceramic powder, 5%~8% polymer, and the remainder is solvent; Based on the total mass of the raw materials of the outer layer as 100%, it includes the following raw material components by mass percentage: ceramic powder 60%~65%, inorganic powder 0.5%~2%, polymer 5%~8%, and the balance being solvent; The ceramic powder includes Ba （1.01~1.1） Ce 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ The inorganic powder includes transition metal oxides. The thickness ratio of the inner layer, the middle layer, and the outer layer is (2.8~3):(4.1~4.3):1; The hollow fiber membrane has a wall thickness of 443.6~452.73μm and an inner diameter of 998.6~1089.2μm.

2. The hollow fiber membrane as described in claim 1, characterized in that, The thickness ratio of the inner layer, the middle layer and the outer layer is 2.85:4.29:

1.

3. The hollow fiber membrane as described in claim 1, characterized in that, The inorganic powder includes nickel oxide; The particle size of the inorganic powder is 50~100μm.

4. The hollow fiber membrane as described in claim 1, characterized in that, The method for preparing the ceramic powder includes the following steps: According to the stoichiometric ratio, barium source, cerium source, zirconium source, yttrium source and ytterbium source are mixed evenly, and then a solid-phase reaction is carried out at 900~1100℃ to obtain the ceramic powder.

5. A method for preparing a hollow fiber membrane according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Weigh each raw material according to the design ratio and prepare the inner layer casting solution, the middle layer casting solution and the outer layer casting solution respectively. S2. Vacuum degassing, co-spinning, and drying are performed on the inner layer casting solution, the middle layer casting solution, and the outer layer casting solution to obtain hollow fiber precursor. S3. The hollow fiber precursor is sintered at 1420~1460℃ to obtain a hollow fiber membrane.

6. The method for preparing the hollow fiber membrane as described in claim 5, characterized in that, In S2, the volumetric flow rate ratio of the inner layer casting liquid, the middle layer casting liquid, and the outer layer casting liquid is (1~2):(4~8):(1~2). In S3, the sintering time is 3~7h; In S3, the temperature is increased to 1420~1460℃ at a rate of 0.5~5℃ / min.

7. The application of the hollow fiber membrane according to any one of claims 1 to 4 in hydrogen separation and recovery.

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