Air oxygen-enriched equipment, oxygen-enriched combustion gas supply system and method

Abstract

The present invention discloses an air oxygen enrichment device, an oxygen-enriched combustion system and an oxygen-enriched combustion method. For the air oxygen enrichment device of the present invention, by adding a magnetic field outside the membrane separation device 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. For the oxygen-enriched combustion system of the present invention, for the membrane separation module, flue gas rich in CO<subgt;2< / subgt; is selected as the purge gas of the membrane separation module, directly realizing the mixed combustion of CO<subgt;2< / subgt>-rich flue gas and O<subgt;2< / subgt>-rich gas, solving the problems of low oxygen enrichment efficiency in the existing magnetic method and difficulty in oxygen detaching from the enrichment magnetic field, and the whole 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 oxygen-enriched combustion. Background Art

[0002] At present, China's carbon emission reduction and capture technologies have been relatively mature. Carbon capture is mainly carried out in industries such as coal chemical industry, thermal power industry, steel manufacturing, natural gas processing, cement production, methanol, synthetic ammonia, hydrogen production and oil refining. Economic cost is an important factor restricting the development of CCUS in China. Among the capture, transportation, utilization and storage links of CCUS, carbon capture is the link with the highest energy consumption and cost. Compared with China's carbon dioxide emissions and emission reduction requirements, the current emission reduction contribution of CCUS is still very low, making it difficult to meet China's urgent need for low-carbon development.

[0003] Oxygen-enriched combustion is an efficient and energy-saving combustion technology. Oxygen-enriched combustion refers to combustion with oxygen-enriched air with a higher oxygen concentration than air. Compared with combustion with ordinary air, it can effectively increase the flame temperature, improve the thermal utilization rate, and reduce the flue gas loss. Moreover, with the continuous development of oxygen-enriched preparation technology, it has become easier to obtain oxygen-enriched air. Therefore, the oxygen-enriched combustion technology is applied more and more widely and has been gradually extended to pulverized coal furnaces, circulating fluidized beds and industrial heating furnaces. Oxygen-enriched combustion can also realize carbon capture during the combustion process. During the oxygen-enriched combustion process, by simultaneously assisting with a combustion technology of flue gas recirculation, high-concentration CO2-rich flue gas 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 CCUS technologies most likely to be widely promoted and commercialized.

[0004] The cost of oxygen enrichment is the key factor affecting the overall investment and operating expenses of the oxy-fuel combustion technology. Currently, the main oxygen enrichment technologies 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. It has mature technology and high oxygen purity, but high energy consumption, and is mainly used for pure oxygen combustion in large enterprises to capture CO2. Pressure swing adsorption (PSA) separates gases by using the adsorption and desorption capabilities of adsorbents for specific gases. It can be used for medium- and small-scale gas separation. Usually, two or more tanks are required for switching adsorption and regeneration operations, with problems such as high-frequency action leakage and high failure rate of switching valves, and high regeneration energy consumption. 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 to clean. 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 through a high magnetic field to obtain oxygen-enriched air and nitrogen-enriched air, with 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.

[0005] Although oxy-fuel combustion has many advantages, under oxy-fuel combustion conditions, as the volume fraction of oxygen enrichment increases, the flame temperature rises, and more thermal nitrogen oxides will be generated, resulting in an increase in the concentration of nitrogen oxides in the flue gas, which also restricts the popularization and application of oxy-fuel combustion to a certain extent. Therefore, it is very crucial to adopt appropriate low-nitrogen emission reduction technologies during the oxy-fuel combustion process.

[0006] CN104271217A discloses an oxygen separator and a method for generating oxygen, which uses an oxygen separation adsorbent to achieve the oxygen separation process through multi-period continuous operation. To continuously supply oxygen, multiple groups of oxygen separators need to be switched for operation, and only a small amount of oxygen can be supplied. Patent CN101857200A uses magnetic separation technology and discloses a new type of combined magnetic oxygen enrichment device. The oxygen enrichment device uses three-stage series oxygen enrichment to gradually increase the oxygen purity, but there is a problem that oxygen is difficult to separate from the magnetic field during actual operation.

[0007] Patent CN106545846A discloses a low-NOx flue gas recirculation oxy-fuel combustion device and method for a heating furnace. The device includes a main flue and a flue gas recirculation 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 the 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 problem of oxy-fuel cost. 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. By using the 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 change all the original heating system burners to oxy-fuel burners before it can be applied, and the investment cost is relatively high. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide an air enrichment equipment, an oxy-fuel combustion gas supply system and a method. The present invention can efficiently and low-costly provide a large amount of enriched oxygen 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 the CO2 concentration in the flue gas, providing convenient conditions for the subsequent capture and recovery of CO2.

[0009] To achieve the object of the present invention, in the first aspect of the present invention, an air enrichment equipment is provided, and the air enrichment equipment is a nitrogen / oxygen magnetic method-membrane combined separation equipment.

[0010] An air enrichment equipment includes a housing, an intermediate cavity, a raw material gas cavity, a residual gas cavity, a membrane separation module and a magnetic field module; wherein

[0011] The raw material gas cavity and the residual gas cavity are respectively located at both ends of the housing, and the intermediate cavity is located between the raw material gas cavity and the residual gas cavity;

[0012] The membrane separation module is arranged in the intermediate cavity of the air enrichment equipment, and its two open ends are respectively communicated with the raw material gas cavity and the residual gas cavity, dividing the intermediate cavity into a residual channel and a permeation channel; wherein, the raw material gas cavity and the residual gas cavity form a residual gas channel through the middle cavity of the membrane separation module; opposite to the residual gas channel, the space between the membrane separation modules is the permeation channel;

[0013] The raw material gas cavity and the residual gas cavity are respectively provided with a raw material gas inlet and a residual gas outlet;

[0014] One side of the housing is provided with a permeate gas outlet, and the permeate gas outlet is communicated with the permeation channel of the membrane separation module;

[0015] The magnetic field component is arranged around or on both sides of the outer shell, and is used to form a magnetic field within the housing area of the air oxygen enrichment device.

[0016] Furthermore, the tube wall of the membrane separation component is made of a membrane separation material, which has good selective permeability to oxygen and relatively slower permeability to 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). The membrane separation material can be a natural membrane material, an inorganic membrane material, a polymer membrane material, or a composite membrane material.

[0017] Furthermore, the membrane separation component is in the form of a hollow tube with double openings, that is, both ends of the hollow membrane tube are open.

[0018] Furthermore, multiple groups of the membrane separation components are provided. The multiple groups of membrane separation components correspondingly form multiple groups of residual gas channels with the raw gas cavity and the residual gas cavity.

[0019] Furthermore, the magnetic field component is composed of multiple groups of magnets, and the magnets can be permanent magnets, electromagnetic magnets, or superconducting magnets.

[0020] Furthermore, a magnetic concentrating medium is installed in the permeation channel between several membrane separation components. The magnetic concentrating medium is a substance that can transform a uniform magnetic field into a non-uniform magnetic field with a high gradient, and can be one or several combinations of spherical media, toothed plate media, mesh media, rod media, steel wool media, etc. The material of the magnetic concentrating medium can be one or several of pure iron, low-carbon steel, ferromagnetic stainless steel of ferrite type, and iron-cobalt-neodymium-boron alloy, etc.

[0021] Furthermore, the air oxygen enrichment device has a raw gas inlet, a permeated gas outlet, and a residual gas outlet. The raw gas inlet and the residual gas outlet are communicated with the residual channel of the membrane separation component, and the permeated gas outlet is communicated with the permeation channel of the membrane separation component.

[0022] The air oxygen enrichment device 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 the supply of oxygen-enriched gas in fields such as metal smelting, environmental protection treatment of waste water and waste gas, chemical synthesis oxidation reaction, engine oxygen enrichment, medical care oxygen supply, and aquaculture.

[0023] According to the second aspect of the present invention, the present invention provides an oxygen-enriched combustion gas supply system, which includes the air oxygen enrichment device described above.

[0024] An oxygen-enriched combustion air supply system, the system includes an air filter, a combustion-supporting induced draft fan, an air oxygen enrichment device, a mixer, a heat exchanger, a combustion furnace, a flue gas circulation fan, and a dehydration tank; the inlet of the air filter communicates with the atmosphere; the outlet of the air filter is connected to the raw gas inlet of the air oxygen enrichment device; the permeate gas outlet of the air oxygen enrichment device is connected to the inlet of the combustion-supporting induced draft fan, and the residue gas outlet of the air oxygen enrichment device communicates with the atmosphere; the outlet of the combustion-supporting induced draft fan is connected to the first inlet of the mixer; the second inlet of the mixer is communicated with the gas outlet of the dehydration tank through a pipeline, and the outlet of the mixer is communicated with the combustion-supporting air inlet of the gas furnace through the heat exchanger; the flue gas outlet of the combustion furnace is connected to the inlet of the flue gas circulation fan through the 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 second inlet of the mixer.

[0025] Further, the dehydration tank is a cooling dehydration gas-liquid separation tank, and a refrigerant heat extraction facility is provided inside.

[0026] Further, the heat exchanger is a gas-gas heat exchanger, and the form of the heat exchanger is not limited.

[0027] Further, the combustion furnace can be a combustion furnace using solid fuel, liquid fuel, and gas fuel. The combustion furnace has a fuel supply port, a combustion-supporting air supply port, and a flue gas discharge pipeline.

[0028] According to the third aspect of the present invention, the present invention also provides an oxygen-enriched combustion method, in which the air separation system described above is applied.

[0029] [[ID=F15]]An oxygen-enriched combustion method, including the following steps:

[0030] (1) Air is introduced into the air oxygen enrichment device by the combustion-supporting induced draft fan for treatment. In the air oxygen enrichment device, oxygen is enriched in the permeation channel, nitrogen is enriched in the residue channel, the oxygen-enriched gas is led out of the air oxygen enrichment device by the combustion-supporting induced draft fan through the permeation channel, and the nitrogen in the residue channel is discharged out of the system;

[0031] (2) The oxygen-enriched gas led out by the combustion-supporting induced draft fan in step (1) enters the mixer and is mixed with the CO2-rich flue gas treated by the dehydration tank. After mixing and heat exchange, it enters the combustion furnace as combustion-supporting air and burns with the fuel. After the high-temperature flue gas generated by combustion recovers heat through heat exchange, it is pressurized by the flue gas circulation fan. After pressurization, the flue gas is divided into two paths: the first path enters the dehydration tank for cooling, temperature reduction, and dehydration treatment, and the second path is discharged out of the system;

[0032] (3) The low-temperature flue gas treated by the dehydration tank in step (2) enters the mixer and is mixed with the oxygen-enriched gas, and then is used as combustion-supporting air.

[0033] Further, an air filter is provided in front of the air oxygen enrichment device in step (1) to filter impurities in the air.

[0034] Further, the volume concentration of CO2 in the flue gas after being treated by the dehydration tank in step (2) is higher than 20%.

[0035] Further, the gas discharged from the permeate side of the air oxygen enrichment device in step (1) is oxygen-enriched gas (used as combustion-supporting air), and the volume concentration of O2 in the oxygen-enriched gas is generally 30% - 60%.

[0036] Further, the temperature of the dehydration tank in step (2) is 10 - 60 °C, preferably 25 - 40 °C.

[0037] Further, the flue gas divided into two paths after being pressurized by the circulating 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.

[0038] Further, the CO2-rich flue gas discharged from the second path of the system in step (2) can be further subjected to carbon capture or recovery treatment.

[0039] The oxygen-enriched combustion method provided by the present invention is applicable to the oxygen-enriched combustion process of various types of combustion furnaces for solid fuels, liquid fuels and gas fuels.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. The present invention proposes an air oxygen enrichment device. The present invention adds a magnetic field outside the membrane separation device, and cooperates with the poly-magnetic medium filled in the middle of the membrane material. By utilizing the different paramagnetism and diamagnetism of oxygen molecules and nitrogen molecules, and through the mutual cooperation of the magnetic field and the poly-magnetic medium, the oxygen enrichment effect of simple membrane separation is greatly improved. In addition, the form of suction by the induced draft fan is used to timely take out the gas after oxygen enrichment treatment from the device (magnetic field area), solving the problems of low oxygen enrichment efficiency in the existing magnetic oxygen enrichment method and difficulty in separating oxygen from the enrichment magnetic field. The entire oxygen enrichment and gas supply process is continuous and stable.

[0042] 2. Using air oxygen enrichment to separate nitrogen and oxygen from air, the separation of nitrogen reduces the combustion-supporting air volume, thereby reducing the flue gas generation amount, lowering the heat loss of flue gas discharge, improving the thermal efficiency of the heating furnace, and reducing the generation of raw material nitrogen oxides. From the source, the nitrogen oxide emissions are reduced and controlled. Cooperating with the recycling and regeneration of CO2-rich flue gas and mixing with oxygen-enriched gas, it is equivalent to using CO2 to replace N2 as the dilution gas, greatly increasing the concentration of CO2 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

[0043] Figure 1 It is a schematic diagram of an air separation system described in the present invention.

[0044] In the figure, 1 - air pipeline, 2 - filter, 3 - combustion-supporting induced draft fan, 4 - heat exchanger, 5 - combustion furnace, 6 - flue gas circulation fan, 7 - air oxygen enrichment 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 - flue gas outlet of the combustion furnace, 15 - carbon capture and recovery device, 16 - residual gas discharge pipeline, 17 - mixer.

[0045] Figure 2 This is a schematic structural diagram of the air oxygen enrichment device of the present invention.

[0046] In the figure, 51 - outer shell, 52 - intermediate cavity, 53 - residual gas cavity, 54 - membrane separation module, 55 - magnetic field module, 56 - raw gas inlet, 57 - raw gas entrance, 58 - permeate gas outlet, 59 - residual gas outlet, 60 - permeation channel, 61 - residual channel.

[0047] Figure 3 This is a schematic structural diagram of the magnetic method - membrane separation module of the present invention.

[0048] In the figure, 62 - magnetic medium, 63 - membrane separation material. Specific embodiments

[0049] The following will describe in detail an air oxygen enrichment device, an oxygen-enriched combustion gas supply system and a method of the present invention with reference to the accompanying drawings and embodiments, but the present invention is not limited thereto.

[0050] Embodiment 1

[0051] This embodiment describes in detail an oxygen / nitrogen air oxygen enrichment device. As Figure 2As shown in the figure, the oxygen-enriched air device of the present invention is a magnetic-membrane combined separation device, which includes an outer casing 51, an intermediate cavity 52, a raw gas cavity 56, a residual gas cavity 53, a membrane separation module 54 and a magnetic field module 55. The raw gas cavity 56 and the residual gas cavity 53 are respectively located at both ends of the outer casing 51. The membrane separation module 54 is in the form of a hollow tube with double openings, that is, both ends of the hollow membrane tube are open. The membrane separation module 54 is arranged in the intermediate cavity 52 inside the outer casing, and the two open ends are respectively connected to the raw gas cavity 56 and the residual gas cavity 53, dividing the intermediate cavity 52 into a residual channel 61 and a permeation channel 60. Among them, the raw gas cavity 56 and the residual gas cavity 53 form a residual channel 61 through the middle cavity of the membrane separation module 54. The membrane separation module 54 is provided in multiple groups, and correspondingly forms multiple groups of residual channels 61 with the raw gas cavity 56 and the residual gas cavity 53. The raw gas cavity 56 and the residual gas cavity 53 are respectively provided with a raw gas inlet 57 and a residual gas outlet 59. An permeation gas outlet 58 is provided on one side of the outer casing 51, and the permeation gas outlet 58 is connected to the permeation channel 60 of the membrane separation module. The magnetic field module 55 is arranged around or on both sides of the outer casing 51 of the membrane separation device.

[0052] As Figure 3 shown in the figure, the tube wall of the membrane separation module 54 is a membrane separation material 63, and the permeation channels between the membrane separation modules are filled with a poly-magnetic medium 62.

[0053] Embodiment 2

[0054] This embodiment describes the oxygen-enriched combustion gas supply system of the present invention in detail.

[0055] As Figure 1 shown in the figure, the present invention provides an air separation system, which includes an air filter 2, a combustion-supporting fan 3, an oxygen-enriched air device 7, a heat exchanger 4, a combustion furnace 5, a flue gas circulation fan 6, a dehydration tank 10, and a mixer 17. The inlet of the air filter 2 is communicated with the atmosphere; the outlet of the air filter 2 is connected to the raw gas inlet of the oxygen-enriched air device 7; the permeation gas outlet of the oxygen-enriched air device 7 is connected to the inlet of the combustion-supporting induced draft fan 3, and the residual gas outlet of the oxygen-enriched air device 7 is discharged to the atmosphere; the outlet of the combustion-supporting induced draft fan 3 is connected to the inlet of the mixer 17; the other inlet of the mixer 17 is connected to the outlet pipeline of the dehydration tank 10, and the outlet of the mixer 17 is connected to the combustion-supporting air inlet 13 of the gas furnace through the heat exchanger 4; 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 inlet of the mixer 17.

[0056] Embodiment 3

[0057] This embodiment describes in detail the oxygen-enriched combustion gas supply method of the present invention. In combination with Figures 1-3 , the working process of a magnetic air separation system and an oxygen-enriched combustion method provided by the present invention is as follows: Air is introduced into the air oxygen enrichment device 7 by the combustion-supporting induced draft fan 3 for treatment. In the air oxygen enrichment device 7, oxygen has a high membrane permeation performance and is enriched on the permeate side 60, while nitrogen has a low membrane permeation performance and is enriched in the retentate channel 61. The oxygen-enriched gas is led out of the air oxygen enrichment device 7 by the combustion-supporting induced draft fan 3 through the permeate channel, and the nitrogen in the retentate channel is discharged out of the system 16; The oxygen-enriched gas led out by the combustion-supporting induced draft fan 3 enters the mixer 17 and is mixed with the CO2-rich flue gas treated by the dehydration tank 10. After mixing and heat exchange, it enters the combustion furnace 5 as combustion-supporting air and burns with the fuel. After the high-temperature flue gas 14 generated by combustion recovers heat through heat exchange, 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. After the treated low-temperature flue gas enters the mixer and is mixed with the oxygen-enriched gas, it is used as combustion-supporting air; The second path is discharged out of the system and can be further subjected to carbon capture or recovery treatment.

[0058] Example 4

[0059] This embodiment gives a specific application case of a magnetic oxygen-enriched gas supply combustion system.

[0060] Adopt Figure 1 A magnetic oxygen-enriched gas supply combustion system provided by the present invention as shown is used for oxygen-enriched combustion treatment of a 5MW gas heating furnace of an enterprise. The fuel gas is natural gas. The air oxygen enrichment device adopts the Figure 2 structure shown. The membrane material is selected as a polymethylsiloxane / polycarbonate polymer nitrogen / oxygen separation membrane. The ferromagnetic medium in the membrane separation module is selected as 100μm iron-chromium alloy steel wool medium, and the external magnetic field is selected as a neodymium iron boron (Nd2Fe 14 B) alloy permanent magnet, which can be magnetized regularly, with a magnetic field strength > 1T and a magnetic field gradient > 1000T / m.

[0061] Air is pressurized by the combustion-supporting blower 3 and then enters the air oxygen enrichment device 7 for treatment. In the air oxygen enrichment 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 retentate channel. At the same time, the flue gas rich in CO2 (with a CO2 volume fraction of about 21%) enters the permeation channel of the air oxygen enrichment device 7 as the purge gas from the purge gas inlet, and exits the air oxygen enrichment device together with the oxygen-enriched gas through the permeation channel. At this time, the volume fractions of each component of the combustion-supporting air are: about 24% for O2, about 61% for N2, about 8% for CO2, and the rest is water. The nitrogen in the retentate channel is discharged out of the system 16; the oxygen-enriched gas discharged from the permeation channel of the air oxygen enrichment 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, accounting for 41% of the total flue gas volume, enters the dehydration tank 16 for cooling, temperature reduction and dehydration treatment, and then enters the air oxygen enrichment 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 21%, 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 flue gas generation amount is reduced, the heat loss of the exhaust gas is reduced, the thermal efficiency of the heating furnace is improved, and the nitrogen oxide emissions can be effectively controlled. Compared with the air combustion-supporting process, the flue gas discharge amount is reduced by 48%, and the CO2 concentration in the flue gas is increased from about 10% to 21%, which is equivalent to reducing the scale of the subsequent carbon capture equipment by nearly 50%, greatly reducing the carbon capture cost, and providing convenient conditions for the subsequent capture and recovery of CO2.

Claims

1. An air oxygen enrichment device, comprising a housing, an intermediate cavity, a raw gas cavity, a residual gas cavity, a membrane separation assembly and a magnetic field assembly; wherein The raw gas cavity and the residual gas cavity are respectively located at both ends of the housing, and the intermediate cavity is located between the raw gas cavity and the residual gas cavity; The membrane separation module is arranged in the middle cavity of the air oxygen enrichment device, and its two open ends are respectively communicated with the raw gas cavity and the residual gas cavity, dividing the middle cavity into a residual channel and a permeation channel; wherein, The raw gas cavity and the residual gas cavity form a residual gas channel through the middle cavity of the membrane separation assembly; the space between the membrane separation assemblies is a permeation channel; The raw gas cavity and the residual gas cavity are respectively provided with a raw gas inlet and a residual gas outlet; An oxygen permeate outlet is provided on one side of the housing, and the oxygen permeate outlet is communicated with the permeation channel of the membrane separation assembly; The magnetic field assembly is arranged around or on both sides of the housing for forming a magnetic field in the housing area of the air oxygen enrichment device; the permeation channels between a plurality of membrane separation assemblies are filled with a magnetic concentrating medium.

2. The oxygen-enriched air device according to claim 1, characterized in that, The tube wall of the membrane separation assembly is a membrane separation material, and the separation selectivity of the membrane material for O2 / N2 is greater than 2.

3. The oxygen-enriched air device according to claim 1, wherein The membrane separation assembly is in the form of a hollow tube with double openings, that is, both ends of the hollow membrane tube are open.

4. The oxygen-enriched air equipment according to claim 1, wherein The membrane separation assemblies are arranged in multiple groups.

5. The oxygen-enriched air device according to claim 1, wherein, The magnetic field assembly is composed of multiple groups of magnets, and the magnets are permanent magnets, electromagnetic magnets or superconducting magnets.

6. The oxygen-enriched air device according to claim 1, wherein The magnetic concentrating medium is a substance for changing a uniform magnetic field into a non-uniform magnetic field with a high gradient.

7. The oxygen-enriched air device according to claim 1 or 6, characterized in that, The magnetic concentrating medium is one or a combination of spherical medium, toothed plate medium, mesh medium, rod medium, steel wool medium, and the material of the magnetic concentrating medium is one or a combination of pure iron, low-carbon steel, ferromagnetic stainless steel and iron-cobalt-neodymium-boron alloy.

8. The oxygen-enriched air device according to claim 1, wherein The raw gas inlet and the residual gas outlet are communicated with the residual channel of the membrane separation assembly, and the oxygen permeate outlet is communicated with the permeation channel of the membrane separation assembly.

9. An oxygen-enriched combustion gas supply system, which contains the air oxygen enrichment device according to any one of claims 1-8.

10. The oxygen-enriched combustion gas supply system according to claim 9, characterized in that, The system includes an air filter, a combustion-supporting induced draft fan, an air oxygen enrichment device, a mixer, a heat exchanger, a combustion furnace, a flue gas circulation fan, a dehydration tank; the inlet of the air filter is communicated with the atmosphere; the outlet of the air filter is connected with the raw gas inlet of the air oxygen enrichment device; the oxygen permeate outlet of the air oxygen enrichment device is connected with the inlet of the combustion-supporting induced draft fan, and the residual gas outlet of the air oxygen enrichment device is communicated with the atmosphere; the outlet of the combustion-supporting induced draft fan is connected with the first inlet of the mixer; the second inlet of the mixer is communicated with the gas outlet of the dehydration tank through a pipeline, and the outlet of the mixer is communicated with the combustion-supporting air inlet of the gas furnace through a heat exchanger; the flue gas outlet of the combustion furnace is connected with 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 with 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 with the second inlet of the mixer.

11. The oxygen-enriched combustion gas supply system according to claim 10, wherein The dehydration tank is a cooling dehydration gas-liquid separation tank, and a refrigerant heat extraction facility is arranged inside.

12. An oxygen-enriched combustion method, which applies the oxygen-enriched combustion gas supply system according to any one of claims 9-11.

13. The oxygen-enriched combustion method according to claim 12, wherein It includes the following steps: (1) Air is introduced into the air oxygen enrichment device by the combustion-supporting induced draft fan for treatment. In the air oxygen enrichment device, oxygen is enriched on the permeation side, nitrogen is enriched on the residual side, the oxygen-enriched gas is led out of the air oxygen enrichment device by the combustion-supporting induced draft fan from the permeation side, and the nitrogen on the residual side is discharged out of the system; (2) The oxygen-rich gas led out by the combustion-supporting induced draft fan in step (1) enters the mixer and is mixed with the CO2-rich flue gas treated by the dehydration tank. After mixing and heat exchange, it enters the combustion furnace as combustion-supporting air and burns with the fuel. After the high-temperature flue gas generated by combustion recovers heat through heat exchange, it is pressurized by the flue gas circulation fan. After pressurization, the flue gas is divided into two paths: the first path enters the 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 mixer and is mixed with the oxygen-rich gas, and then is used as combustion-supporting air.

14. The oxy-fuel combustion method according to claim 13, wherein, An air filter is provided in front of the air oxygen enrichment equipment in step (1) to filter impurities in the air.

15. The oxygen-enriched combustion method according to claim 13, characterized in that, The volume concentration of CO2 in the high-temperature flue gas generated by combustion in step (2) is higher than 20%.

16. The oxy-fuel combustion method according to claim 13, wherein The O2 volume concentration of the gas discharged from the permeation channel of the air oxygen enrichment equipment in step (1) is 30% - 60%.

17. The oxy-fuel combustion method according to claim 13, wherein, The temperature of the dehydration tank in step (2) is 10 - 60 °C.

18. The oxy-fuel combustion method according to claim 14, characterized in that, 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.

19. The oxygen-enriched combustion method according to claim 13, wherein, The gas discharged out of the system through the second path is subjected to carbon capture or recovery treatment.

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