Magnetic method membrane separation equipment, oxygen-enriched air supply system and oxygen-enriched combustion method

Abstract

The present invention discloses a magnetic membrane separation device, an oxygen-enriched gas supply system and an oxygen-enriched combustion method. The magnetic membrane separation device of the present invention increases a magnetic field outside the membrane separation device, and cooperates with the poly-magnetic medium filled in the membrane material. By utilizing the different paramagnetism and diamagnetism of oxygen molecules and nitrogen molecules, and with the mutual cooperation of the magnetic field and the poly-magnetic medium, the oxygen-enriched effect of simple membrane separation is greatly improved. For the membrane separation module in the oxygen-enriched combustion gas supply system of the present invention, flue gas rich in CO2 is selected as the purge gas for the membrane separation module, directly realizing the mixed combustion of CO2-rich flue gas and O2-rich gas, solving the problems of low oxygen-enriched efficiency of the existing magnetic method and difficulty in detaching oxygen from the enrichment magnetic field, and the entire oxygen-enriched gas supply process is continuous and stable.

Description

Technical Field

[0001] The present invention belongs to the technical field of heating furnaces, and relates to a technology and method for energy conservation, emission reduction and carbon reduction of heating furnaces, in particular to a system and method for realizing energy conservation, emission reduction and carbon reduction of heating furnaces by means of oxy-fuel combustion. Background Technique

[0002] Oxy-fuel combustion is an efficient and energy-saving combustion technology, which uses oxygen-enriched air with a higher oxygen concentration than air for combustion. Compared with ordinary air combustion, it can effectively increase the flame temperature, improve the thermal utilization rate, and reduce the flue gas loss. At present, it has been gradually promoted to pulverized coal furnaces, circulating fluidized beds and industrial heating furnaces, etc. Oxy-fuel combustion can also achieve carbon capture during the combustion process. By providing oxygen-enriched gas and assisting with flue gas recycle combustion technology, high-concentration flue gas rich in CO2 can be obtained to achieve carbon enrichment, thereby reducing the scale, investment and operating costs of the post-combustion carbon capture device, and realizing CO2 recovery or resource utilization at a relatively low cost. It has many advantages such as relatively low cost, easy scale-up, and the ability to retrofit existing units, and is considered to be one of the most likely CCUS technologies to be widely promoted and commercialized.

[0003] The cost of oxygen enrichment is the key to restricting the overall investment and operating costs of oxy-fuel combustion technology. The current oxygen enrichment technologies mainly include cryogenic separation, pressure swing adsorption, membrane separation and magnetic oxygen enrichment, etc. Cryogenic separation uses the boiling point differences of each component after liquefaction for rectification separation. The process is mature and the oxygen purity is high, but the energy consumption is large, and it is mainly used for pure oxygen combustion in large enterprises to capture CO2. Pressure swing adsorption (PSA) uses the adsorption and desorption capabilities of adsorbents for specific gas components to separate gases, and can be used for medium- and small-scale gas separation. Usually, two or more tanks are required for switching adsorption and regeneration operations, and there are problems such as high-frequency action leakage and high failure rate of the switching valve, and the regeneration energy consumption is relatively high. Membrane separation technology uses membrane materials with special selective separation properties to separate air, and is suitable for medium- and small-scale low-purity oxygen production. The key to membrane technology is to manufacture membrane materials with high flux, high selectivity, long service life and easy cleaning. However, in actual applications, there are problems such as membrane pore blockage of the oxygen-enriched membrane caused by dust, impurities, etc., which shortens the service life of the membrane. Magnetic oxygen enrichment uses the different paramagnetism and diamagnetism of oxygen molecules and nitrogen molecules, so that the two gas molecules deflect in different directions when passing through a high magnetic field, obtaining oxygen-enriched air and nitrogen-enriched air, which has the advantages of low energy consumption and low oxygen enrichment cost. However, existing magnetic oxygen enrichment devices generally have problems such as low efficiency, low oxygen enrichment concentration, small oxygen-enriched gas volume, and difficulty in separating oxygen from the enrichment magnetic field.

[0004] Although oxy-fuel combustion has many advantages, under oxy-fuel combustion conditions, as the volume fraction of oxygen increases, the flame temperature rises, and more thermal NOx will be generated, resulting in an increase in the concentration of NOx in the flue gas. This also restricts the popularization and application of oxy-fuel combustion to a certain extent. Therefore, in the process of oxy-fuel combustion, it is very crucial to adopt appropriate low-nitrogen emission reduction technologies.

[0005] CN104271217A discloses an oxygen separator and a method for generating oxygen. The oxygen separation process is realized by using an oxygen separation adsorbent through multi-cycle continuous operation. To achieve continuous oxygen supply, multiple groups of oxygen separators need to be switched for operation, and only a small amount of oxygen supply can be provided. Patent CN101857200A uses magnetic separation technology and discloses a new type of combined magnetic oxygen enrichment device. The oxygen enrichment device adopts three-stage series oxygen enrichment to gradually increase the oxygen purity. However, in the actual operation process, there is a problem that it is difficult for oxygen to detach from the magnetic field.

[0006] Patent CN106545846A discloses a low-NOx flue gas circulation oxy-fuel combustion device and method for a heating furnace. The device includes a main flue and a flue gas circulation branch flue. By circulating a part of the flue gas discharged from the heating furnace and mixing it with oxygen at the same time to form a mixed gas with an oxygen content of 21% - 30% and sending it into the burner as combustion-supporting gas, the generation of NOx in the flue gas is greatly reduced. However, this technology requires a stable oxygen source supply and does not consider the source and cost of the oxygen-enriched gas. Patent CN103343965A discloses a heating furnace system using oxy-fuel combustion. The invention relates to a heating furnace system in which air and oxygen are pre-mixed and then supplied to the burner for combustion. Using oxy-fuel combustion technology, the effective utilization of low-calorific value gas can be realized, and it is more efficient, energy-saving and environmentally friendly. However, it needs to convert all the original heating system burners into oxy-fuel burners before it can be applied, and the investment cost is relatively high. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a magnetic membrane separation device, an oxygen-enriched gas supply system and an oxy-fuel combustion method. The present invention can efficiently and low-costly provide a large amount of oxygen-enriched gas for oxy-fuel combustion, and can reduce and control nitrogen oxide emissions from the source, improve the thermal efficiency of the heating furnace, reduce the flue gas emissions and recover the flue gas waste heat. At the same time, it enriches CO2 in the flue gas, providing convenient conditions for the subsequent capture and recovery of CO2.

[0008] According to the first aspect of the present invention, the present invention provides a magnetic membrane separation device, and the magnetic membrane separation device can be used to provide oxygen-enriched gas with a low nitrogen content for an oxygen-enriched combustion gas supply system.

[0009] A magnetic membrane separation device includes a housing, an intermediate cavity, a purge gas cavity, a permeate gas cavity, a plurality of membrane separation components and a magnetic field component; wherein,

[0010] The internal space of the outer shell body is respectively a purge gas cavity, an intermediate cavity, and a permeate gas cavity from one end to the other end;

[0011] The membrane separation module is arranged in the intermediate cavity and is in the form of a hollow tubular double-opening membrane; the two openings at both ends of the membrane separation module are respectively communicated with the purge gas cavity and the permeate gas cavity, dividing the intermediate cavity into a retentate channel and a permeate channel;

[0012] The purge gas cavity is provided with a purge gas inlet, the permeate gas cavity is provided with a permeate gas outlet, and the raw material gas inlet and the retentate gas outlet are respectively arranged on both sides of the outer shell body;

[0013] The magnetic field module is arranged around or on both sides of the outer shell body and is used to form a magnetic field in the area of the outer shell body;

[0014] The permeate gas channel of the membrane separation module is filled with a magnetic concentrating medium, and the magnetic concentrating medium is used to change the uniform magnetic field into a non-uniform magnetic field with a high gradient.

[0015] Furthermore, the magnetic field module is composed of multiple groups of magnets, and the magnets can be permanent magnets, electromagnetic magnets, or superconducting magnets.

[0016] Furthermore, the hollow cavity inside the membrane separation module is the permeate channel, and the space between several membrane separation modules forms the retentate channel.

[0017] Furthermore, the magnetic concentrating medium is a substance that can change the uniform magnetic field into a non-uniform magnetic field with a high gradient. The magnetic concentrating medium can be one or a combination of spherical medium, toothed plate medium, mesh medium, rod medium, steel wool medium, etc.; the material of the magnetic concentrating medium can be one or a combination of pure iron, low-carbon steel, ferromagnetic stainless steel, and iron-cobalt-neodymium-boron alloy, etc.

[0018] Furthermore, the membrane separation material has good selective permeation performance for oxygen and relatively slow permeation performance for nitrogen compared to oxygen. The selectivity of the membrane material for O2 / N2 is greater than 2 (i.e., the ratio of the permeation rates of O2 and N2), and the membrane separation material can be a natural membrane material, an inorganic membrane material, a polymer membrane material, or a composite membrane material.

[0019] Furthermore, multiple groups of the membrane separation modules are arranged, corresponding to form multiple groups of permeate gas channels with the purge gas cavity and the permeate gas cavity. The raw material gas inlet and the retentate gas outlet are preferably arranged at positions close to both ends on both sides of the shell body and are communicated with the retentate channel of the membrane separation module.

[0020] Furthermore, the purge gas cavity and the permeate gas cavity are respectively located at both ends of the outer shell body.

[0021] The magnetic membrane separation equipment of the present invention can be used to provide oxygen-enriched combustion-supporting air for an oxygen-enriched combustion system, and can also be used for oxygen-enriched gas supply in fields such as metal smelting, environmental protection treatment of wastewater and waste gas, chemical synthesis oxidation reaction, engine oxygen enrichment, medical care oxygen supply, and aquaculture.

[0022] According to the second aspect of the present invention, the present invention provides an oxygen-enriched combustion gas supply system, which includes the magnetic membrane separation equipment described above.

[0023] An oxygen-enriched combustion gas supply system, the system includes an air filter, a combustion-supporting fan, a magnetic membrane separation equipment, a heat exchanger, a combustion furnace, a flue gas circulation fan, and a dehydration tank; the inlet of the combustion-supporting fan is communicated with the atmosphere through a filter, and the outlet of the combustion-supporting fan is connected to the raw gas inlet of the magnetic membrane separation equipment; the permeate gas outlet of the magnetic membrane separation equipment is connected to the combustion-supporting air inlet of the combustion furnace through a heat exchanger, and the retentate gas outlet of the magnetic membrane separation equipment is communicated with the atmosphere; the flue gas outlet of the combustion furnace is connected to the inlet of the flue gas circulation fan through a heat exchanger; the outlet of the flue gas circulation fan is divided into two paths, the first path is connected to the inlet of the dehydration tank, and the second path is discharged out of the system; the outlet pipeline of the dehydration tank is connected to the purge gas inlet of the magnetic membrane separation equipment.

[0024] Further, the dehydration tank is a cooling dehydration gas-liquid separation tank, and a refrigerant heat extraction facility is provided inside.

[0025] Further, the heat exchanger is a gas-gas heat exchanger, and the form of the heat exchanger is not limited.

[0026] Further, the combustion furnace can be a combustion furnace for solid fuel, liquid fuel and gas fuel, and the combustion furnace has a fuel supply port, a combustion-supporting air supply port and a flue gas discharge pipeline.

[0027] Further, the magnetic membrane separation equipment has the structure described above.

[0028] According to the third aspect of the present invention, the present invention provides a method for supplying oxygen-enriched combustion gas, in which the system described above is applied, and the method for supplying oxygen-enriched combustion gas includes the following steps:

[0029] (1) Air is pressurized by the combustion-supporting fan and then enters the magnetic membrane separation equipment for treatment. In the separation equipment, oxygen has a high membrane permeability and is enriched in the permeation channel, and nitrogen has a low membrane permeability and is enriched in the retentate channel; at the same time, the purge gas enters the permeation channel of the membrane separation equipment from the purge gas inlet, and is discharged from the membrane separation equipment together with the oxygen-enriched gas through the permeation channel, and the nitrogen-enriched gas in the retentate channel is discharged out of the system;

[0030] (2)The oxygen-rich gas discharged from the permeation channel of the magnetic method membrane separation equipment in step (1) is used as combustion-supporting air to enter the combustion furnace and burn with the fuel after heat exchange. After the high-temperature flue gas generated by combustion recovers heat through heat exchange, it is pressurized by the flue gas circulation fan and divided into two paths: the first path enters the dehydration tank for cooling, temperature reduction and dehydration treatment, and the second path is discharged outside the system;

[0031] (3)The low-temperature flue gas treated by the dehydration tank in step (2) enters the membrane separation equipment as purging gas to carry out the process of discharging the gas from the permeation channel of the membrane separation equipment described in step (1).

[0032] Furthermore, an air filter is provided in front of the combustion-supporting fan in step (1) to filter impurities in the air.

[0033] Furthermore, the high-temperature flue gas in step (2) is a flue gas rich in CO2, and the volume concentration of CO2 in the flue gas is higher than 20%.

[0034] Furthermore, the gas discharged from the permeation channel of the magnetic method membrane separation equipment in step (1) is oxygen-rich gas, and the volume concentration of O2 in the combustion-supporting air is ≥21%.

[0035] Furthermore, the temperature of the dehydration tank in step (2) is 10 - 60 °C, preferably 25 - 40 °C.

[0036] Furthermore, the two paths into which the flue gas is divided after being pressurized by the circulation fan in step (2), the first path accounts for 10% - 60% of the total flue gas volume, and the second path accounts for 40% - 90% of the total flue gas volume.

[0037] Furthermore, the gas discharged outside the system in the second path in step (2) is a flue gas rich in CO2, which can be further subjected to carbon capture or recovery treatment.

[0038] The oxygen-rich combustion gas supply method of the present invention is applicable to the oxygen-rich combustion process of various types of combustion furnaces using solid fuels, liquid fuels and gas fuels.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. The present invention proposes a magnetic method - membrane combined oxygen / nitrogen membrane separation equipment. By adding a magnetic field outside the membrane separation equipment and cooperating with the poly-magnetic medium filled in the membrane material, taking advantage of the different paramagnetism and diamagnetism of oxygen molecules and nitrogen molecules, and with the mutual cooperation of the magnetic field and the poly-magnetic medium, the oxygen enrichment effect of simple membrane separation is greatly improved.

[0041] 2. For the oxygen-enriched combustion gas supply system of the present invention, for the membrane separation module, the flue gas rich in CO2 is selected as the purge gas for the membrane separation module, and the functions are as follows: First, it can provide the transmembrane driving force for oxygen to pass through the membrane material module. The purge gas is rich in CO2 gas, which can reduce the partial pressure of oxygen on the permeate side (channel) to a certain extent, reduce the oxygen concentration difference between the two sides, and promote the oxygen separation effect; Second, it can timely take out the gas after oxygen enrichment treatment from the equipment, improving the separation efficiency; In addition, during the purging process, the direct mixing of the CO2-rich flue gas and the O2-rich gas is realized, and the combustion-supporting air with the required oxygen concentration is proportioned and then burned with the fuel, and the oxygen-enriched combustion of the furnace can be realized without modifying the original combustion system.

[0042] 3. For a proposed magnetic membrane separation device, using the flue gas rich in CO2 as the purge gas for the membrane separation module can timely take out the gas after oxygen enrichment treatment from the equipment (magnetic field area), solving the problems of low oxygen enrichment efficiency and difficulty in separating oxygen from the enrichment magnetic field in the existing magnetic oxygen enrichment, and the entire oxygen supply process is continuous and stable.

[0043] 4. Using the magnetic membrane separation device to separate nitrogen and oxygen from air, the separation of nitrogen reduces the combustion-supporting air volume, thereby reducing the flue gas generation amount, reducing the heat loss of flue gas discharge, improving the thermal efficiency of the heating furnace, and reducing the generation of raw material nitrogen oxides, reducing and controlling nitrogen oxide emissions from the source. Cooperating with the CO2-rich flue gas circulation regeneration and mixing with the oxygen-rich gas, it is equivalent to using CO2 instead of N2 as the dilution gas, greatly increasing the CO2 concentration in the flue gas and significantly reducing the carbon capture cost, providing convenient conditions for the subsequent capture and recovery of CO2. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the oxygen-enriched combustion gas supply system described in the present invention.

[0045] In the figure, 1 - air pipeline, 2 - filter, 3 - combustion-supporting fan, 4 - heat exchanger, 5 - combustion furnace, 6 - flue gas circulation fan, 7 - membrane separation device, 8 - burner, 9 - fuel supply, 10 - dehydration tank, 11 - first outlet of the circulation fan, 12 - second outlet of the circulation fan, 13 - combustion-supporting air inlet, 14 - combustion furnace flue gas outlet, 15 - carbon capture and recovery device, 16 - residual gas discharge pipeline.

[0046] Figure 2 It is a schematic diagram of the structure of the magnetic-membrane combined separation device described in the present invention.

[0047] In the figure, 51 - outer shell, 52 - purge gas cavity, 53 - permeate gas cavity, 54 - membrane separation module, 55 - magnetic field module, 56 - raw material gas inlet, 57 - purge gas inlet, 58 - residual gas outlet, 59 - permeate gas outlet, 60 - residual channel, 61 - permeate channel.

[0048] Figure 3 This is a schematic structural diagram of the magnetic method - membrane separation component of the present invention.

[0049] In the figure, 62 is the magnetic medium aggregator, and 63 is the membrane separation material. Specific embodiments

[0050] The following describes in detail the magnetic method membrane separation equipment, oxygen - enriched gas supply system and oxygen - enriched combustion method of the present invention with reference to the accompanying drawings and embodiments, but does not limit the present invention thereby.

[0051] Embodiment 1

[0052] This embodiment describes the magnetic method membrane separation equipment in detail. As Figure 2 shown, the structure of the magnetic method - membrane combined separation equipment of the present invention is as follows: The separation equipment includes a housing 51, a purge gas cavity 52, a permeate gas cavity 53, a membrane separation component 54 and a magnetic field component 55. The purge gas cavity 52 and the permeate gas cavity 53 are respectively located at both ends of the housing 51. The membrane separation component 54 is in the form of a hollow membrane. The membrane separation component 54 is arranged between the purge gas cavity 52 and the permeate gas cavity 53, dividing the middle cavity into a retentate channel 60 and a permeate channel 61. Among them, the purge gas cavity 52 and the permeate gas cavity 53 form the permeate channel 61 through the middle cavity of the membrane separation component 54. The membrane separation components are arranged in multiple groups, corresponding to form multiple permeate channels 61 with the purge gas cavity and the permeate gas cavity. The purge gas cavity 52 and the permeate gas cavity 53 are respectively provided with a purge gas inlet 57 and a permeate gas outlet 59. The raw material gas inlet 56 and the retentate gas outlet 58 are respectively arranged on both sides of the housing 51 at positions close to both ends, and are communicated with the retentate channel 60 of the membrane separation component. The magnetic field component 55 is arranged around or on both sides of the housing 51 of the membrane separation equipment.

[0053] As Figure 3 shown, the structure of the magnetic method - membrane separation component of the system and method of the present invention is as follows: The tube wall of the membrane separation component 54 is the membrane separation material 63, and the middle channel of the membrane separation component is filled with the magnetic medium aggregator 62.

[0054] Embodiment 2

[0055] This embodiment describes the oxygen - enriched combustion gas supply system of the present invention in detail.

[0056] As Figure 1As shown in the figure, the oxygen-enriched combustion gas supply system of the present invention includes an air filter 2, a combustion-supporting fan 3, a membrane separation device 7, a heat exchanger 4, a combustion furnace 5, a flue gas circulation fan 6, and a dehydration tank 10; the inlet of the combustion-supporting fan is communicated with the atmosphere through the filter 2; the outlet of the combustion-supporting fan 3 is connected to the raw gas inlet of the membrane separation device 7; the permeate gas outlet of the membrane separation device 7 is connected to the combustion-supporting air inlet 13 of the gas furnace through the heat exchanger 4, and the residue gas outlet 16 of the membrane separation device is discharged to the atmosphere; the flue gas outlet 14 of the combustion furnace is connected to the inlet of the flue gas circulation fan 6 through the heat exchanger 4; the outlet of the flue gas circulation fan is divided into two paths, the first path 11 is connected to the inlet of the dehydration tank 10, and the second path 12 is discharged out of the system; the outlet pipeline of the dehydration tank 10 is connected to the purge gas inlet of the membrane separation device 7.

[0057] Example 3

[0058] This embodiment describes in detail the oxygen-enriched combustion gas supply method of the present invention. Combining Figures 1 - 3 the working process of the magnetic oxygen-enriched combustion gas supply system and method of the present invention is as follows: The air is pressurized by the combustion-supporting fan 3 and then enters the membrane separation device 7 for treatment. In the membrane separation device 7, oxygen has a high membrane permeation performance and is enriched in the permeation channel, while nitrogen has a low membrane permeation performance and is enriched in the residue channel. At the same time, the purge gas enters the permeation channel of the membrane separation device 7 from the purge gas inlet and is discharged from the membrane separation device together with the oxygen-enriched gas through the permeation channel, and the nitrogen in the residue channel is discharged out of the system 16; the oxygen-enriched gas discharged from the permeation channel of the membrane separation device 7 is used as combustion-supporting air to enter the combustion furnace 5 to burn with the fuel after heat exchange. After the high-temperature flue gas 14 generated by combustion is heat-exchanged to recover heat, it is pressurized by the flue gas circulation fan 6 and divided into two paths: the first path 11 enters the dehydration tank 10 for cooling, temperature reduction and dehydration treatment and then enters the membrane separation device 7 as purge gas, and the second path 15 is discharged out of the system, and further carbon capture or recovery treatment can be carried out.

[0059] Example 4

[0060] This embodiment gives a specific application case of an oxygen-enriched gas supply combustion system. Using Figure 1 the oxygen-enriched gas supply combustion system shown in the figure to carry out oxygen-enriched combustion treatment on a 5MW gas heating furnace of an enterprise. The fuel gas is natural gas. The membrane separation device adopts Figure 2 the structure shown in the figure. The membrane material is selected as a silicone / polysulfone nitrogen / oxygen composite separation membrane. The ferromagnetic medium in the membrane separation module is 100μm iron-chromium alloy steel wool medium, and the external magnetic field uses an electromagnet, with a magnetic field strength > 3T and a magnetic field gradient > 2000T / m.

[0061] After the air is pressurized by the combustion-supporting blower 3, it enters the membrane separation device 7 for treatment. Inside the membrane separation device 7, oxygen has a high membrane permeability and is enriched on the permeate side, while nitrogen has a low membrane permeability and is enriched on the retentate side. At the same time, the flue gas rich in CO2 (with a CO2 volume fraction of about 25%) enters the permeate side of the membrane separation device 7 as the purge gas from the purge gas inlet, and is discharged from the membrane separation device together with the oxygen-rich gas from the permeate side. At this time, the volume fractions of the components of the combustion-supporting air are as follows: O2 is about 22%, N2 is about 66%, CO2 is about 11%, and the rest is water. The nitrogen on the retentate side is discharged out of the system 16; the oxygen-rich gas discharged from the permeate side of the membrane separation device 7 is used as the combustion-supporting air to enter the combustion furnace 5 to burn with the fuel after heat exchange. After the high-temperature flue gas 14 generated by combustion exchanges heat to recover heat, it is pressurized by the flue gas circulation blower 6 and divided into two paths: the first path accounts for 50% of the total flue gas volume and enters the dehydration tank 16 for cooling, temperature reduction and dehydration treatment, and then enters the membrane separation device 7 as the purge gas. The second path is the remaining flue gas discharged out of the system. The CO2 volume concentration in the discharged gas is about 25%, and further carbon capture or recovery treatment can be carried out.

[0062] Due to the optimization of the membrane separation oxygen enrichment combined with the flue gas circulation purge process in the above process, without modifying the original burner of the heating furnace, the amount of flue gas generated is reduced, the heat loss of the exhaust gas is reduced, the thermal efficiency of the heating furnace is improved, and the emission of nitrogen oxides can be effectively controlled. Compared with the air combustion-supporting process, the overall thermal efficiency of the combustion furnace is increased by more than 1%, the external discharge amount of flue gas is reduced by 52%, and the CO2 concentration in the flue gas is increased from about 10% to 25%, which is equivalent to reducing the scale of the subsequent carbon capture equipment by more than 50%, greatly reducing the carbon capture cost, and providing convenient conditions for the subsequent capture and recovery of CO2.

Claims

1. A magnetic membrane separation device, comprising a housing, an intermediate cavity, a purge gas cavity, a permeate gas cavity, a plurality of membrane separation modules, and a magnetic field module; Among them, The internal space of the housing is, from one end to the other end, a purge gas cavity, an intermediate cavity, and a permeate gas cavity respectively; the membrane separation modules are arranged in the intermediate cavity and are in the form of hollow tubular double-open membranes; The two ends of the membrane separation module are respectively communicated with the purge gas cavity and the permeate gas cavity, dividing the intermediate cavity into a retentate channel and a permeate channel; The purge gas cavity is provided with a purge gas inlet, the permeate gas cavity is provided with a permeate gas outlet, and the two sides of the housing are respectively provided with a raw material gas inlet and a retentate gas outlet; The magnetic field module is arranged around or on both sides of the housing for forming a magnetic field in the housing area; The permeate channel of the membrane separation module is filled with a magnetic medium, and the magnetic medium is used for changing the uniform magnetic field into a non-uniform magnetic field with a high gradient.

2. The magnetic method membrane separation device according to claim 1, characterized in that, The magnetic field module is composed of multiple groups of magnets, and the magnets are permanent magnets, electromagnetic magnets or superconducting magnets.

3. The magnetic membrane separation device according to claim 1, wherein The membrane separation module is a tubular membrane module, a hollow fiber membrane module or a spiral wound membrane module.

4. The magnetic membrane separation device according to claim 1, characterized in that, The hollow cavity inside the membrane separation module is the permeate channel, and the space between several membrane separation modules constitutes the retentate channel.

5. The magnetic membrane separation device according to claim 1, characterized in that The magnetic medium is used for changing the uniform magnetic field into a non-uniform magnetic field with a high gradient.

6. The magnetic membrane separation device according to claim 1 or 5, characterized in that, The magnetic medium is one or a combination of spherical medium, tooth plate medium, mesh medium, rod medium, steel wool medium; the material of the magnetic medium is one or a combination of pure iron, low-carbon steel, ferromagnetic stainless steel of ferrite, and iron-cobalt-neodymium-boron alloy.

7. The magnetic membrane separation device according to claim 1, characterized in that, The tube wall of the membrane separation module is a membrane separation material, and the selectivity of the membrane separation material for O2 / N2 is greater than 2.

8. The magnetic membrane separation device according to claim 1, characterized in that, Multiple groups of the membrane separation modules are arranged, correspondingly forming multiple groups of permeate channels.

9. The magnetic membrane separation device according to claim 1, characterized in that, The raw material gas inlet and the retentate gas outlet are respectively arranged at positions close to the two ends on both sides of the housing and are communicated with the retentate channel.

10. The magnetic method membrane separation device according to claim 1, wherein, The purge gas cavity and the permeate gas cavity are respectively located at both ends of the housing.

11. An oxygen-enriched combustion gas supply system, which comprises the magnetic membrane separation device according to any one of claims 1-10.

12. The oxygen-enriched combustion gas supply system according to claim 11, characterized in that, The system comprises an air filter, a combustion-supporting fan, a magnetic membrane separation device, a heat exchanger, a combustion furnace, a flue gas circulation fan, and a dehydration tank; The inlet of the combustion-supporting fan is communicated with the atmosphere through a filter, and the outlet of the combustion-supporting fan is connected to the raw material gas inlet of the magnetic membrane separation device; The permeate gas outlet of the magnetic membrane separation device is connected to the combustion-supporting air inlet of the combustion furnace through a heat exchanger, and the retentate gas outlet of the magnetic membrane separation device is communicated with the atmosphere; The flue gas outlet of the combustion furnace is connected to the inlet of the flue gas circulation fan through a heat exchanger; the outlet of the flue gas circulation fan is divided into two paths, the first path is connected to the inlet of the dehydration tank, and the second path is discharged out of the system; the outlet pipeline of the dehydration tank is connected to the purge gas inlet of the magnetic membrane separation device.

13. The oxygen-enriched combustion gas supply system according to claim 12, wherein The dehydration tank is a cooling dehydration gas-liquid separation tank, and a refrigerant heat extraction facility is arranged inside.

14. The oxygen-enriched combustion air supply system according to claim 12, wherein The combustion furnace is a combustion furnace using solid fuel, liquid fuel or gas fuel, and the combustion furnace has a fuel supply port, a combustion-supporting air supply port and a flue gas discharge pipeline.

15. An oxygen-enriched combustion gas supply method, in which the oxygen-enriched combustion gas supply system according to any one of claims 11-14 is applied.

16. The oxygen-enriched combustion gas supply method according to claim 15, characterized in that, It includes the following steps: (1) Air is pressurized by a combustion-supporting blower and then enters a magnetic membrane separation device for treatment. In the magnetic membrane separation device, oxygen has a high membrane permeation performance and is enriched in the permeation channel, while nitrogen has a low membrane permeation performance and is enriched in the retentate channel; Meanwhile, the purge gas enters the permeation channel of the magnetic membrane separation device from the purge gas inlet, and exits the magnetic membrane separation device from the permeation channel together with the oxygen-rich gas, and the nitrogen in the retentate channel is discharged out of the system; (2) The oxygen-rich gas discharged from the permeation channel of the magnetic membrane separation device in step (1) is used as combustion-supporting air to enter a combustion furnace to burn with fuel after heat exchange. After the heat in the high-temperature flue gas generated by combustion is recovered through heat exchange, it is pressurized by a flue gas circulation blower and divided into two paths: the first path enters a dehydration tank for cooling, temperature reduction and dehydration treatment, and the second path is discharged out of the system; (3) The low-temperature flue gas treated by the dehydration tank in step (2) enters the membrane separation device as the purge gas.

17. The oxygen-enriched combustion gas supply method according to claim 16, wherein, An air filter is provided in front of the combustion-supporting blower in step (1) to filter impurities in the air.

18. The oxygen-enriched combustion gas supply method according to claim 16, characterized in that, The volume concentration of CO2 in the high-temperature flue gas in step (2) is higher than 20%.

19. The oxygen-enriched combustion gas supply method according to claim 16, characterized in that The gas discharged from the permeation side of the magnetic membrane separation device in step (1) is oxygen-rich gas combustion-supporting air, and the volume concentration of O2 in the combustion-supporting air is ≥21%.

20. The oxygen-enriched combustion gas supply method according to claim 16, characterized in that, The temperature of the dehydration tank in step (2) is 10~60°C.

21. The oxygen-enriched combustion gas supply method according to claim 16, characterized in that The two paths into which the flue gas is divided after being pressurized by the circulation blower in step (2), the first path accounts for 10%~60% of the total flue gas volume, and the second path accounts for 40%~90% of the total flue gas volume.

22. The oxygen-enriched combustion gas supply method according to claim 16, characterized in that, The gas discharged out of the system in the second path in step (2) is CO2-rich flue gas, which is further subjected to carbon capture or recovery treatment.

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