Oxygen-enriched air preparation device based on magnetic field and membrane separation coupling at normal temperature

Abstract

The invention discloses an oxygen-enriched air preparation device based on magnetic field and membrane separation coupling at normal temperature, comprising: a gas separation membrane vertically arranged along an airflow direction; the permanent magnet array is arranged between the two vertically arranged gas separation membranes; the permanent magnet array comprises a plurality of layers of permanent magnet units, and gas flow channels are formed in the areas between the adjacent permanent magnet units. The permanent magnet array generates a high magnetic field gradient at normal temperature through topological optimization design; the magnetic conductive medium is arranged in the airflow channel along the airflow direction and is used for gathering magnetic lines of force; the shell, the gas separation membrane and the permanent magnet array form a closed device; the air inlet is formed in the end cover at the inlet end of the shell and is used for introducing compressed air into the sealing device; and the oxygen-enriched outlet is formed in an end cover at the outlet end of the shell and is used for outputting oxygen enriched under the combined action of the magnetic field and the gas separation membrane. The oxygen-enriched air preparation device can realize high-efficiency, low-energy-consumption, compact-structure and stable-operation oxygen-enriched air preparation.

Description

Technical Field

[0001] The present invention relates to the technical field of gas separation, and particularly to an apparatus for preparing oxygen-enriched air based on the coupling of magnetic field and membrane separation at room temperature. Background Art

[0002] Oxygen-enriched air has wide applications in fields such as industrial combustion, healthcare, and water treatment. Traditional air separation technologies, such as cryogenic distillation, can produce high-purity oxygen, but the equipment is large and energy consumption is high, making it unsuitable for small-scale or low-concentration oxygen-enriched demands. Pressure swing adsorption (PSA) and membrane separation methods are more common in medium and small-scale applications. However, PSA devices still have certain energy consumption and noise, and for the preparation of low-concentration oxygen-enriched air by simple membrane separation, it often faces problems such as difficulty in balancing permeation flux and selectivity and high energy consumption.

[0003] Magnetically induced air separation using the difference in magnetic susceptibilities between the paramagnetism of oxygen and the diamagnetism of nitrogen is a potential low-energy consumption technology. The magnetic susceptibility of oxygen is much greater than that of nitrogen, and it will be subjected to a magnetic force pointing to the strong magnetic field region in a gradient magnetic field. For example, the Chinese patent document with the publication number CN207270992U discloses a nitrogen-oxygen magnetic separation device, which includes a separation tank, a magnetic separator, an air flow inlet, an oxygen-enriched air outlet, and a nitrogen-enriched air outlet. The magnetic separator is composed of two magnets with opposite poles facing each other, and the magnetic field direction formed by the two magnets is perpendicular to the air flow direction.

[0004] However, the magnetic field gradient generated by traditional room-temperature permanent magnets is limited, and the magnetic separation efficiency is not high when used alone, and the improvement of oxygen-enriched concentration is limited.

[0005] To improve the magnetic separation efficiency, some studies have proposed to enhance the magnetic field strength and gradient, such as using superconducting magnets. For example, the Chinese patent document with the publication number CN 105561728 A discloses a cryogenic air separator using the superconducting Meissner effect. It uses a superconducting magnet to generate a strong magnetic field and operates in a cryogenic liquid or supercritical state, and uses the extremely high magnetic field gradient generated at the edges of the micropores of the superconducting thin film to separate oxygen and nitrogen. Although this method has high efficiency in theory, it relies on expensive superconducting magnets and complex cryogenic systems, with high operation and maintenance costs, huge energy consumption, and is not suitable for room-temperature and small-scale application scenarios.

[0006] Therefore, how to use permanent magnets to achieve high-efficiency and low-energy consumption preparation of oxygen-enriched air at room temperature, especially to meet small-scale and low-concentration oxygen-enriched demands, remains an urgent technical problem to be solved.

[0007] In addition, existing membrane separation oxygen-enriched devices lack fine control of the gas flow path, and the gas contacts the membrane unevenly, resulting in the membrane separation efficiency being restricted by the material properties, and the static operation mode cannot dynamically respond to the oxygen concentration fluctuation, and the output purity stability is poor. Summary of the Invention

[0008] The present invention provides an apparatus for preparing oxygen-enriched air based on the coupling of magnetic field and membrane separation at room temperature, which combines two technologies with complementary mechanisms of magnetic separation and membrane separation, and optimizes the design of the magnetic field structure and the flow field to achieve efficient, low-energy consumption, compact structure, and stable operation for the preparation of oxygen-enriched air.

[0009] An apparatus for preparing oxygen-enriched air based on the coupling of magnetic field and membrane separation at room temperature, comprising:

[0010] A gas separation membrane, vertically arranged along the gas flow direction, and composed of a membrane material with selective permeability to oxygen;

[0011] A permanent magnet array, arranged between two vertically arranged gas separation membranes; the permanent magnet array includes multiple layers of permanent magnet units, and the regions between adjacent permanent magnet units form gas flow channels; the permanent magnet array is optimized by topology design to generate a high magnetic field gradient at room temperature, and the magnetic field gradually increases along the gas flow direction to enhance the magnetic capture force for paramagnetic oxygen;

[0012] A magnetic conduction medium, arranged in the gas flow channel along the gas flow direction, for aggregating magnetic lines of force;

[0013] A housing, forming a closed device with the gas separation membrane and the permanent magnet array; end caps are provided at both ends of the housing;

[0014] An air inlet, arranged on the end cap at the inlet end of the housing, for introducing compressed air into the closed device;

[0015] An oxygen-enriched outlet, arranged on the end cap at the outlet end of the housing, for outputting the oxygen enriched after the combined action of the magnetic field and the gas separation membrane.

[0016] Furthermore, through the magnetic field superposition effect, the permanent magnet array generates a magnetic field gradient in the range of 200 T² / m to 400 T² / m along the gas flow direction in the gas flow channel.

[0017] Optionally, the permanent magnet unit adopts a neodymium iron boron permanent magnet.

[0018] Optionally, the magnetic conduction medium is a ferromagnetic material in the form of strips, filaments or thin sheets, which is used to guide oxygen molecules closer to the oxygen-enriched outlet direction in the macroscopic gas flow direction, and at the same time promote the diffusion of diamagnetic nitrogen molecules in the direction away from the magnetic conduction medium.

[0019] Furthermore, the magnetic conductive medium is strongly magnetized by a high-gradient permanent magnet array, concentrating magnetic field lines and forming local gradient peaks at the edge or surface of the magnetic conductive medium. When air flows through, paramagnetic oxygen molecules are not only attracted by the macroscopic magnetic force of the permanent magnet array but also captured and guided by the strong local gradient near the magnetic conductive medium, causing them to tend to cling to the surface of the magnetic conductive medium or move along a specific path formed by the magnetic conductive medium towards the oxygen-rich outlet direction.

[0020] Furthermore, a partition is provided on the inner side of the end cap, and ventilation holes or flow guiding vanes matching the gas flow channel are provided on the partition to divide the air flow into multiple laminar flows, ensuring that the gas uniformly flows through the surface of the gas separation membrane and the action area of the magnetic conductive medium after entering the gas flow channel; avoiding air flow dead zones or short circuits, prolonging the gas residence time, improving the uniformity of membrane surface contact, and maximizing the efficiency of magnetic separation and membrane separation.

[0021] Furthermore, the gas separation membrane is composed of multiple layers of polymer materials, and the polymer materials are preferably polyimide (PI), cellulose acetate (CA), polysulfone (PSF), polyethersulfone (PES), polyamide (PA) or their copolymers or mixtures, having high oxygen / nitrogen selectivity, high strength and corrosion resistance.

[0022] In the present invention, the entire device can adopt a modular design, and the permanent magnet array, the magnetic conductive medium and the gas separation membrane can be independently disassembled and replaced.

[0023] Preferably, the gas flow channel can adopt an asymmetric flow channel design, enabling the gas to form an optimized spiral flow path in the housing to ensure that the air flow evenly sweeps across the membrane surface and the magnetic field action area, improving the separation efficiency.

[0024] To further improve stability, the oxygen-rich air preparation device further includes a flow control system;

[0025] The flow control system includes a controller, a flow meter and / or a concentration sensor provided at the oxygen-rich outlet, and a flow controller provided at the air inlet or the oxygen-rich outlet;

[0026] The controller adjusts the intake air volume or the outlet air volume in real time according to the feedback of the outlet oxygen concentration or flow rate to maintain a stable oxygen-rich concentration.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention achieves a high-gradient magnetic field (200 - 400 T2 / m) at room temperature through a topologically optimized multi-channel stacked neodymium iron boron permanent magnet array, which is more than 30% higher than the traditional single-channel structure, getting rid of the dependence on low-temperature cooling and reducing energy consumption.

[0029] 2. In the present invention, a high-permeability medium is embedded in the air flow channel of the permanent magnet, and by utilizing the aggregation effect of the magnetic conduction medium on magnetic field lines, a local magnetic field gradient peak region is formed to precisely control the physical separation path of oxygen adhering to the magnetic conduction medium for enrichment and nitrogen reverse diffusion, thereby realizing the magnetic-fluid coupling separation mechanism. Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0031] Figure 1 It is a schematic diagram of the nitrogen-oxygen separation principle of an oxygen-enriched air preparation device based on the coupling of magnetic field and membrane separation at room temperature according to the present invention.

[0032] Figure 2 It is a schematic diagram of the overall structure of an oxygen-enriched air preparation device based on the coupling of magnetic field and membrane separation at room temperature according to the present invention.

[0033] Figure 3 It is Figure 2 a cross-sectional view of

[0034] Figure 4 It is Figure 2 a cross-sectional view from another angle.

[0035] Figure 5 It is a flow chart of air separation using the oxygen-enriched air preparation device of the present invention.

[0036] In the figure: 1 - air inlet; 2 - end cover; 3 - gas separation membrane; 4 - permanent magnet array; 5 - magnetic conduction medium; 6 - partition board; 7 - oxygen-enriched outlet; 11 - nitrogen; 12 - oxygen. Detailed Embodiments

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0038] It should be noted that, without conflict, the features in the following embodiments and implementation manners can be combined with each other.

[0039] Such as Figures 2 to 4As shown in the figure, an oxygen-rich air preparation device based on the coupling of magnetic field and membrane separation at room temperature mainly includes an air inlet 1, an end cap 2, a gas separation membrane 3, a permanent magnet array 4, a magnetic conductive medium 5, a partition 6, and an oxygen-rich outlet 7.

[0040] Compressed air enters the gradient magnetic field provided by the permanent magnet array 4 from the air inlet 1. The permanent magnet array 4 is composed of multiple high-performance permanent magnet units. These units are designed through topology optimization and arranged in a multi-channel stacked manner (as Figure 3 shown), and are placed parallelly in the middle of the two gas separation membranes 3.

[0041] The goal of the topology optimization design is to maximize the magnetic field gradient in the gas flow channel under the given permanent magnet material usage and space constraints. Specifically, first, a finite element model of the permanent magnet array is established, and the optimization objective function is set as the integral value of the magnetic field gradient in the gas flow channel. Then, by adjusting parameters such as the shape, size, position, and magnetization direction of the permanent magnet units, iterative calculations are performed using an optimization algorithm, and finally, the permanent magnet array structure that can generate the best magnetic field gradient is obtained. This structure utilizes the principle of magnetic field superposition to generate a magnetic field gradient as high as 200 - 400 T2 / m near the surface of the permanent magnet and inside the channel, and it can be achieved at room temperature without additional refrigeration.

[0042] The magnetic conductive medium 5 is made of high-permeability wire mesh, ferrite sheets, or ferromagnetic materials with special shapes, and is embedded in the air flow channels of the permanent magnet array 4, adjacent to the strong magnetic field region generated by the permanent magnet array 4.

[0043] When air flows through, the magnetic conductive medium 5 is strongly magnetized, gathers magnetic field lines, and forms local gradient peaks at its edge or surface. The paramagnetic oxygen molecules 12 are not only attracted by the macroscopic magnetic force of the permanent magnet array 4, but also captured and guided by the strong local gradient near the magnetic conductive medium 5, making them tend to closely adhere to the surface of the magnetic conductive medium 5 or move along a specific path formed by the medium towards the oxygen-rich outlet 7 (as Figure 1 shown in the separation principle).

[0044] The gas separation membrane 3 is composed of multiple layers of selectively permeable membranes, arranged along the air flow direction. Nitrogen 11 is weakly repelled due to its diamagnetism and is not easily captured by the magnetic conductive medium 5, and is more likely to approach the membrane 3 and be blocked by the membrane, while oxygen 12 can permeate through the gas separation membrane 3, thereby further realizing gas separation.

[0045] The partition 6 is used to separate and fix the internal components of the device, ensuring the stability of gas flow and air pressure balance. Ventilation holes are provided on the partition 6 to balance the internal air pressure and ensure the smooth flow of gas. Air inlets 1 and oxygen-rich outlets 7 are respectively provided at both ends of the end cap 2 to ensure the smooth flow of gas. The separated oxygen-rich gas is output through the oxygen-rich outlet 7, while nitrogen is discharged from the unenclosed sides of the device. The design of the entire device ensures the efficient separation and output of oxygen-rich gas.

[0046] The partition 6 is used to separate and fix the internal components of the device. The opening and microchannel design on it, together with the end cap 2 and other components, ensure that the incoming air can flow evenly through the entire magnetic field action area and the membrane surface, avoiding air flow dead zones or short circuits, and maximizing the efficiency of magnetic separation and membrane separation.

[0047] The flow channel is designed asymmetrically, with air inlet 1 on the left and oxygen-rich gas outlet 7 on the right. The nitrogen outlet is at the unenclosed side of the device, forming an optimized spiral flow path for the gas inside the shell to ensure that the air flow evenly sweeps across the membrane surface and the magnetic field action area.

[0048] The entire device is designed as a modular structure. The permanent magnet array 4, the magnetic conduction medium 5, and the gas separation membrane 3 can be easily disassembled, cleaned, replaced, or upgraded, improving the maintainability and flexibility.

[0049] To further improve the stability, the oxygen-rich air preparation device of the present invention further includes a flow control system.

[0050] The flow control system includes a controller, a flow meter and / or a concentration sensor provided at the oxygen-rich outlet, and a flow controller provided at the air inlet or the oxygen-rich outlet. The controller adjusts the intake air volume or the outlet air volume in real time according to the oxygen concentration or flow feedback at the outlet to maintain a stable oxygen-rich concentration.

[0051] As Figure 5 shown, in this embodiment, a flow controller and an oxygen content analyzer are equipped at the oxygen-rich outlet. Combined with the controller, a high-precision gas flow controller (accuracy ±0.2% F.S) and a multi-channel flow meter are integrated. The inlet flow (3 - 300 ml / min) is dynamically adjusted according to the oxygen concentration at the outlet, forming a real-time feedback control system to achieve closed-loop control of the separation process and ensure the stability of the oxygen concentration increment.

[0052] The above-described embodiments have detailed the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modification, supplement, and equivalent replacement made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An apparatus for preparing oxygen-rich air based on the coupling of magnetic field and membrane separation at room temperature, characterized in that, Comprising: A gas separation membrane (3), vertically arranged along the air flow direction, and composed of a membrane material with selective permeability to oxygen; A permanent magnet array (4), arranged between two vertically arranged gas separation membranes (3); the permanent magnet array (4) includes multiple layers of permanent magnet units, and the regions between adjacent permanent magnet units form gas flow channels; the permanent magnet array (4) is designed through topology optimization to generate a high magnetic field gradient at room temperature, and the magnetic field gradually increases along the air flow direction to enhance the magnetic capture force for paramagnetic oxygen; A magnetic conduction medium (5), arranged in the air flow channel along the air flow direction, for aggregating magnetic lines of force; A housing, forming a closed device with the gas separation membrane (3) and the permanent magnet array (4); end caps (2) are provided at both ends of the housing; An air inlet (1), arranged on the end cap at the inlet end of the housing, for introducing compressed air into the closed device; An oxygen-rich outlet (7), arranged on the end cap at the outlet end of the housing, for outputting the oxygen enriched by the combined action of the magnetic field and the gas separation membrane (3); 2. The oxygen-rich air preparation device based on the coupling of magnetic field and membrane separation at normal temperature according to claim 1, wherein Through the magnetic field superposition effect, the permanent magnet array (4) generates a magnetic field gradient in the gas flow channel within the range of 200 T² / m to 400 T² / m along the air flow direction.

3. The oxygen-enriched air preparation device based on the coupling of magnetic field and membrane separation at normal temperature according to claim 1, wherein The permanent magnet units adopt neodymium iron boron permanent magnets.

4. The oxygen-rich air preparation device based on the coupling of magnetic field and membrane separation at normal temperature according to claim 1, wherein The magnetic conduction medium (5) is a strip-shaped, filamentous or sheet-shaped ferromagnetic material, for guiding oxygen molecules to approach the oxygen-rich outlet (7) direction in the macroscopic air flow direction, and at the same time promoting the diffusion of diamagnetic nitrogen molecules away from the magnetic conduction medium (5); 5. The oxygen-enriched air preparation device based on the coupling of magnetic field and membrane separation at normal temperature according to claim 1, characterized in that, The magnetic conduction medium (5) is strongly magnetized by the permanent magnet array (4) to aggregate magnetic lines of force, forming local gradient peaks at the edge or surface of the magnetic conduction medium (5); when air flows through, paramagnetic oxygen molecules (12) are not only attracted by the macroscopic magnetic force of the permanent magnet array (4), but also captured and guided by the strong local gradient near the magnetic conduction medium (5), making them tend to closely adhere to the surface of the magnetic conduction medium (5) or move along a specific path formed by the magnetic conduction medium (5) towards the oxygen-rich outlet (7); 6. The oxygen-enriched air preparation device based on the coupling of magnetic field and membrane separation at normal temperature according to claim 1, characterized in that A partition plate (6) is provided on the inner side of the end cap (2), and ventilation holes or flow guiding vanes matching the gas flow channels are provided on the partition plate (6) to divide the air flow into multiple laminar flows to ensure that the gas uniformly flows through the surface of the gas separation membrane (3) and the action area of the magnetic conduction medium (5) after entering the gas flow channel; 7. The oxygen-rich air preparation device based on the coupling of magnetic field and membrane separation at room temperature according to claim 1, wherein, The gas separation membrane (3) is composed of multiple layers of polymer materials, and the multiple layers of polymer materials are polyimide PI, cellulose acetate CA, polysulfone PSF, polyethersulfone PES, polyamide PA or their copolymers or mixtures, having high oxygen / nitrogen selectivity, high strength and corrosion resistance; 8. The oxygen-enriched air preparation device based on the coupling of magnetic field and membrane separation at normal temperature according to claim 1, characterized in that, The oxygen-rich air preparation device further includes a flow control system; The flow control system includes a controller, a flow meter and / or a concentration sensor arranged at the oxygen-rich outlet (7), and a flow controller arranged at the air inlet (1) or the oxygen-rich outlet (7); The controller adjusts the intake air volume or the outlet air volume in real time according to the feedback of the outlet oxygen concentration or flow rate to maintain a stable oxygen-rich concentration.

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