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

Abstract

The present invention discloses an air oxygen enrichment device, an oxygen-enriched gas supply system and an oxygen-enriched combustion method. The oxygen-enriched air device of the present invention, by adding a magnetic field outside the membrane separation device, cooperates with the magnetic medium filled in the middle of the membrane material, utilizes the different paramagnetism and diamagnetic properties of oxygen molecules and nitrogen molecules, and relies on the mutual cooperation of the magnetic field and the magnetic medium, thereby greatly improving the oxygen enrichment effect of simple membrane separation. The oxygen-enriched combustion gas supply system of the present invention, for the membrane separation component, selects CO2-rich flue gas as the purge gas of the membrane separation component, directly realizes the mixed combustion of CO2-rich flue gas and O2-rich gas, solves the problems of low oxygen enrichment efficiency of the existing magnetic method, and difficulty of oxygen to separate 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 saving, emission reduction and carbon reduction of heating furnaces, and in particular to a system and method for achieving energy saving, emission reduction and carbon reduction of heating furnaces by utilizing oxygen-enriched combustion. Background Art

[0002] Oxygen-enriched combustion is an efficient and energy-saving combustion technology. It uses oxygen-enriched air with a higher oxygen concentration than air for combustion. Compared with ordinary air combustion, oxygen-enriched combustion can effectively increase flame temperature, improve heat utilization, and reduce smoke exhaust losses. At present, oxygen-enriched combustion technology is increasingly widely used and has been gradually applied to pulverized coal furnaces, circulating fluidized beds, and industrial heating furnaces. Oxygen-enriched combustion can also achieve carbon capture during the combustion process. While providing oxygen-enriched gas and assisting with flue gas circulation combustion technology, high-concentration CO2 flue gas can be obtained to achieve carbon enrichment, reduce the scale, investment and operating costs of post-combustion carbon capture devices, and achieve CO2 recovery or resource utilization at a relatively low cost. It has many advantages such as relatively low cost, easy scalability, and the ability to transform existing units. It is considered to be one of the most likely CCUS technologies to be promoted and commercialized on a large scale.

[0003] The cost of oxygen enrichment is the key factor affecting the overall investment and operating costs of oxygen-enriched combustion technology. The current oxygen-enriched technologies mainly include cryogenic separation, pressure swing adsorption, membrane separation, and magnetic oxygen enrichment. Cryogenic separation is a distillation separation that utilizes the difference in boiling points of the components after liquefaction. The process is mature and the oxygen purity is high, but the energy consumption is relatively high. It is mainly used for large-scale enterprises to capture CO2 by pure oxygen combustion. Pressure swing adsorption (PSA) is a gas separation that utilizes the adsorption and desorption capabilities of adsorbents for specific gas components. It can be used for medium and small-scale gas separation. It usually requires two or more tanks to switch the adsorption regeneration operation. There are problems such as high-frequency leakage and high failure 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. It has the characteristics of simple process, small size, low energy consumption, long service life, and low investment. It is suitable for medium and small-scale low-purity oxygen production. The key to membrane technology is to manufacture high-throughput, high-selectivity, long service life and easy-to-clean membrane materials. However, in actual applications, there are problems such as dust and impurities causing the membrane pores of the oxygen-enriched membrane to be blocked, thereby shortening the service life of the oxygen-enriched membrane. Magnetic oxygen enrichment uses the different paramagnetism and antimagnetism of oxygen molecules and nitrogen molecules to make the two gas molecules deflect in different directions when passing through a high magnetic field to obtain oxygen-enriched and nitrogen-enriched gases. It has the advantages of low energy consumption and low oxygen enrichment cost. However, existing magnetic oxygen enrichment devices generally have low efficiency, low oxygen enrichment concentration, small oxygen enrichment volume, and difficulty in oxygen detaching from the enrichment magnetic field.

[0004] Patent CN101450792A discloses a method for separating air to produce oxygen and nitrogen. The whole process is carried out on a platform composed of a mixed conductor oxygen-permeable ceramic membrane separator and a pressure swing adsorption separator with complex metal oxides as oxygen adsorbents. Most of the oxygen in the air is adsorbed by the mixed conductor oxygen-permeable ceramic membrane, and the remaining air is oxygen-depleted air. The pressure swing adsorption separator with complex metal oxides as adsorbents adsorbs oxygen in the oxygen-depleted air, and then vacuum desorbs oxygen. The separation of nitrogen and oxygen in the air is achieved through two steps of permeation and pressure swing adsorption. The system is complex, has high requirements on the performance of membrane materials, and requires frequent switching of vacuum regeneration. The regeneration process requires the adsorbent to desorb and penetrate the membrane material, and the system has high energy consumption. Patent CN101857200A uses magnetic separation technology to disclose a new type of combined magnetic oxygen enrichment device. The oxygen enrichment device adopts three-stage series oxygen enrichment to gradually improve the oxygen purity, but there is a problem that oxygen is difficult to separate from the magnetic field during actual operation.

[0005] In addition, under oxygen-enriched combustion conditions, as the volume fraction of oxygen increases, the flame temperature rises, more thermal nitrogen oxides will be generated, resulting in an increase in the concentration of nitrogen oxides in the flue gas, which to a certain extent restricts the promotion and application of oxygen-enriched combustion. Therefore, in the process of oxygen-enriched combustion, it is very important to adopt appropriate low-nitrogen emission reduction technology.

[0006] Patent CN103343965A discloses a heating furnace system using oxygen-enriched combustion. The invention relates to a heating furnace system in which air and oxygen are pre-mixed and then supplied to a burner for combustion. The oxygen-enriched combustion technology can realize the effective utilization of low calorific value coal gas, which is more efficient, energy-saving and environmentally friendly. However, it is necessary to change all the burners of the original heating system to oxygen-enriched burners before it can be used, and the investment cost is relatively high. Patent CN106545846A discloses a heating furnace low NOx flue gas circulation oxygen-enriched combustion device and method. 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, oxygen is added to mix and form a mixed gas with an oxygen content of 21% to 30% and send it to the burner as a combustion-supporting gas, which greatly reduces the generation of NOx in the flue gas. However, the technology requires a stable oxygen source supply, and does not consider the source and cost of the oxygen-enriched gas. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention provides an air oxygen enrichment device, an oxygen-enriched gas supply system and an oxygen-enriched combustion method. The present invention can provide a large amount of oxygen-enriched gas for oxygen-enriched combustion at high efficiency and low cost, and can reduce and control nitrogen oxide emissions from the source, improve the thermal efficiency of the heating furnace, reduce flue gas emissions and recover flue gas waste heat, and at the same time enrich CO2 in the flue gas, providing convenient conditions for the subsequent capture and recovery of CO2.

[0008] A first aspect of the present invention provides an air oxygen enrichment device, which is a nitrogen / oxygen membrane separation device and can be used to provide oxygen-enriched gas with a low nitrogen content.

[0009] An air oxygen enrichment device comprises an outer shell, a raw gas cavity, a residual gas cavity, an intermediate cavity, a membrane separation component and a magnetic field component; wherein:

[0010] The raw gas cavity and the residual gas cavity are respectively located at two ends of the inner space of the outer shell; the middle cavity is located between the raw gas cavity and the residual gas cavity;

[0011] The membrane separation component is arranged in the middle cavity; the membrane separation component is a hollow tube double-opening membrane, and the openings at both ends of the membrane separation component are respectively connected to the feed gas cavity and the retentate gas cavity, dividing the middle cavity into a retentate channel and a permeate channel; wherein the hollow cavity of the membrane separation component forms a retentate gas channel, and the cavities between several membrane separation components form a permeate channel;

[0012] The raw gas cavity and the cut gas cavity are respectively provided with a raw gas inlet and a cut gas outlet, and the raw gas inlet and the cut gas outlet are respectively connected to the cut gas channel; the two sides of the outer shell are respectively provided with a purge gas inlet and a permeate gas outlet, and the purge gas inlet and the permeate gas outlet are respectively connected to the permeate channel;

[0013] The magnetic field components are arranged around or on both sides of the outer shell to form a magnetic field in the outer shell area; the permeation channels between the membrane separation components are filled with magnetic concentrating media.

[0014] Furthermore, the membrane separation components are arranged in multiple groups, and correspondingly, the middle cavity of the membrane separation component and the raw gas cavity and the residual gas cavity form multiple groups of residual gas channels.

[0015] Furthermore, the air oxygen enrichment device has a raw gas inlet, a permeate gas outlet, a residue gas outlet and a purge gas inlet. The raw gas inlet and the residue gas outlet are connected to the residue channel of the membrane separation component, and the permeate gas outlet and the purge gas inlet are connected to the permeate channel of the membrane separation component.

[0016] Furthermore, the magnetic field assembly is composed of multiple groups of magnets, which may be permanent magnets, electromagnets or superconducting magnets.

[0017] Furthermore, the purge gas inlet and the permeate gas outlet are arranged at positions close to the two ends on both sides of the outer shell, and are connected to the permeate channel of the membrane separation component.

[0018] Furthermore, the tube wall of the membrane separation component is a membrane separation material. The membrane separation material has good selective permeability to oxygen, and the selectivity of the membrane material to O2 / N2 is greater than 2 (i.e., the permeation rate ratio 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, the magnetic concentrating medium can convert a uniform magnetic field into a high-gradient non-uniform magnetic field. The magnetic concentrating medium can be one or more of a ball medium, a toothed plate medium, a mesh medium, a rod medium, and a steel wool medium. The material of the magnetic concentrating medium can be one or more of pure iron, low-carbon steel, ferrite magnetic stainless steel, and an iron-cobalt-neodymium-boron alloy.

[0020] The air oxygen enrichment equipment of the present invention can be used to provide oxygen-enriched combustion-supporting air for oxygen-enriched combustion systems, and can also be used for the supply of oxygen-enriched gas in the fields of metal smelting, environmental protection treatment of wastewater and exhaust gas, chemical synthesis oxidation reaction, engine oxygen increase, medical care oxygen supply, aquaculture, etc.

[0021] A second aspect of the present invention provides an oxygen-enriched combustion air supply system, which includes the air oxygen-enriching device mentioned above.

[0022] An oxygen-enriched combustion air supply system, the system includes an air filter, a combustion-supporting fan, an air oxygen-enriching device, a heat exchanger, a combustion furnace, a flue gas circulation fan, and a dehydration tank; the combustion-supporting fan inlet is connected to the atmosphere through a filter; the combustion-supporting fan outlet is connected to the raw gas inlet of the air oxygen-enriching device; the permeate gas outlet of the air oxygen-enriching device is connected to the combustion-supporting air inlet of the gas furnace via a heat exchanger, and the intercepted gas outlet of the air oxygen-enriching device is connected to the atmosphere; the flue gas outlet of the combustion furnace is connected to the flue gas circulation fan inlet via a heat exchanger; the flue gas circulation fan outlet is divided into two paths, the first path is connected to the dehydration tank inlet, and the second path is discharged to the outside of the system; the gas outlet of the dehydration tank is connected to the purge gas inlet of the air oxygen-enriching device through a pipeline.

[0023] Furthermore, the dehydration tank is a cooling dehydration gas-liquid separation tank, and a refrigerant heat extraction facility is provided inside.

[0024] Furthermore, the heat exchanger is a gas-gas heat exchanger, and the form of the heat exchanger is not limited.

[0025] Furthermore, the combustion furnace may be 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 smoke exhaust pipeline.

[0026] The third aspect of the present invention also provides a method for supplying gas for oxygen-enriched combustion, in which the oxygen-enriched gas supply system described above is applied.

[0027] The oxygen-enriched combustion gas supply method comprises the following steps:

[0028] (1) After being pressurized by the combustion-supporting fan, the air enters the air oxygen enrichment device for treatment. In the air oxygen enrichment device, oxygen has a higher membrane permeability and is enriched in the permeation channel, while nitrogen has a lower membrane permeability and is enriched in the interception channel. At the same time, the purge gas enters the permeation channel of the air oxygen enrichment device through the purge gas inlet, and is discharged from the air oxygen enrichment device through the permeation channel together with the oxygen-enriched gas, and the nitrogen in the interception channel is discharged to the outside of the system.

[0029] (2) The oxygen-enriched gas discharged from the permeation channel of the air oxygen enrichment device in step (1) enters the combustion furnace as combustion-supporting air after heat exchange and burns with the fuel. The high-temperature flue gas generated after combustion is subjected to heat exchange to recover heat, and then is pressurized by the flue gas circulation fan and divided into two paths: the first path enters the dehydration tank for cooling and dehydration treatment, and the second path is discharged from the system;

[0030] (3) The low-temperature flue gas treated in the dehydration tank in step (2) is used as purge gas and enters the air oxygen enrichment device through the purge gas inlet.

[0031] Furthermore, an air filter is provided before the combustion-supporting blower in step (1) to filter impurities in the air.

[0032] Furthermore, the flue gas in step (2) is CO2-rich flue gas, and the volume concentration of CO2 in the flue gas is higher than 20%.

[0033] Furthermore, the gas discharged from the permeation channel of the air oxygen enrichment equipment in step (1) is oxygen-rich gas, and the volume concentration of O2 in the combustion-supporting air is ≥21%.

[0034] Furthermore, the temperature of the dehydration tank in step (2) is 10-60°C, preferably 25-40°C.

[0035] Furthermore, in step (2), the flue gas is divided into two paths after being pressurized by a circulating fan, the first path accounts for 10% to 60% of the total flue gas, and the second path accounts for 40% to 90% of the total flue gas.

[0036] Furthermore, the gas discharged from the second external exhaust system in step (2) is CO2-rich flue gas, which is further subjected to carbon capture or recovery treatment.

[0037] The oxygen-enriched combustion gas supply method of the present invention is applicable to the oxygen-enriched combustion process of various types of combustion furnaces using solid fuel, liquid fuel and gas fuel.

[0038] Compared with the prior art, the oxygen-enriched combustion system and method of the present invention has the following advantages:

[0039] 1. For membrane separation components, CO2-rich flue gas is used as the purge gas of the membrane separation components, which has the following functions: first, it can provide transmembrane power for oxygen to pass through the membrane material components. The purge gas is CO2-rich gas, which can reduce the partial pressure of oxygen in the permeation channel to a certain extent, reduce the oxygen concentration difference on both sides, and promote the oxygen separation effect; secondly, the oxygen-enriched gas can be brought out of the equipment in time to improve the separation efficiency; in addition, in the process of purge, the CO2-rich flue gas and the O2-rich gas are directly mixed, and the mixture is proportioned into the combustion-supporting air with the required oxygen concentration, and then burned with the fuel. The oxygen-enriched combustion of the furnace can be achieved without modifying the original combustion system.

[0040] 2. An air oxygen enrichment device is proposed. A magnetic field is added outside the membrane separation device, and a magnetic medium is filled on the permeate side between the membrane separation components. The different paramagnetism and diamagnetic properties of oxygen molecules and nitrogen molecules are utilized. Through the mutual cooperation of the magnetic field and the magnetic medium, the oxygen enrichment effect of simple membrane separation is greatly improved.

[0041] 3. For the proposed air oxygen enrichment equipment, CO2-rich flue gas is used as the purge gas for the membrane separation component, which can promptly bring the oxygen-enriched gas out of the equipment (magnetic field area), solving the problems of low efficiency of existing magnetic oxygen enrichment and difficulty in separating oxygen from the enrichment magnetic field. The entire oxygen-enriched gas supply process is continuous and stable.

[0042] 4. Air oxygen enrichment equipment is used to separate nitrogen and oxygen from the air. The separation of nitrogen reduces the amount of combustion-supporting air, thereby reducing the amount of flue gas generated, reducing exhaust heat loss, improving the thermal efficiency of the heating furnace, and reducing the generation of raw nitrogen oxides, thereby reducing and controlling nitrogen oxide emissions from the source. In conjunction with the recycling and regeneration of CO2-rich flue gas and mixing it with oxygen-rich gas, it is equivalent to using CO2 instead of N2 as a dilution gas, which greatly increases the concentration of CO2 in the flue gas and significantly reduces the cost of carbon capture, providing convenient conditions for subsequent CO2 capture and recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of an oxygen-enriched combustion gas supply system according to the present invention.

[0044] In the figure, 1-air pipeline, 2-filter, 3-combustion-supporting fan, 4-heat exchanger, 5-combustion furnace, 6-flue gas circulation fan, 7-air oxygen enrichment equipment, 8-burner, 9-fuel supply, 10-dehydration tank, 11-circulation fan first outlet, 12-circulation fan second outlet, 13-combustion-supporting air inlet, 14-combustion furnace flue gas outlet, 15-carbon capture and recovery device, 16-exhaust pipeline for intercepted residual gas.

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

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

[0047] Figure 3 This is a schematic diagram of the structure of the magnetic-membrane separation component of the present invention.

[0048] In the figure, 62 is a magnetic medium, and 63 is a membrane separation material. DETAILED DESCRIPTION

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

[0050] Example 1

[0051] This embodiment describes the oxygen / nitrogen air enrichment equipment in detail. Figure 2 As shown, the structure of the air oxygen enrichment device of the present invention is as follows: the air oxygen enrichment device comprises an outer shell 51, a raw gas cavity 52, a residual gas cavity 53, a membrane separation component 54 and a magnetic field component 55, wherein the raw gas cavity 52 and the residual gas cavity 53 are respectively located at both ends of the outer shell 51, and the membrane separation component 54 is in the form of a hollow membrane, and the membrane separation component 54 is arranged between the raw gas cavity 52 and the residual gas cavity 53, and the intermediate cavity is divided into a residual gas channel 61 and a permeation channel 60, wherein the raw gas cavity 52 and the residual gas cavity 53 form a cut-off channel 61 through the hollow cavity of the membrane separation component 54 The membrane separation component is provided in multiple groups, and correspondingly forms multiple groups of intercepted residual channels 61 with the raw gas cavity 52 and the intercepted residual gas cavity 53. The raw gas cavity 52 and the intercepted residual gas cavity 53 are respectively provided with a raw gas inlet 57 and a intercepted residual gas outlet 59. The two sides of the outer shell 51 are respectively provided with a purge gas inlet 56 and a permeate gas outlet 58. The purge gas inlet 56 and the permeate gas outlet 58 are arranged at both sides of the shell 51 near the two end positions, and are connected to the permeate channel 60 of the membrane separation component. The magnetic field component 55 is arranged around or on both sides of the outer shell 51 of the air oxygen enrichment equipment.

[0052] like Figure 3 As shown, the structure of the magnetic-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 a membrane separation material 63, and the permeation channels between the membrane separation components are filled with magnetic concentrating media 62.

[0053] Example 2

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

[0055] like Figure 1 As shown, the oxygen-enriched combustion gas supply system provided by the present invention includes the air oxygen enrichment device described above. The system includes an air filter 2, a combustion-supporting fan 3, an air oxygen enrichment device 7, a heat exchanger 4, a combustion furnace 5, a flue gas circulation fan 6, and a dehydration tank 10; the combustion-supporting fan inlet is connected to the atmosphere through the filter 2; the combustion-supporting fan 3 outlet is connected to the raw gas inlet of the air oxygen enrichment device 7; the permeate gas outlet of the air oxygen enrichment device 7 is connected to the combustion-supporting air inlet 13 of the gas furnace through the heat exchanger 4, and the intercepted gas outlet 16 of the air oxygen enrichment device is discharged to the atmosphere; the combustion furnace flue gas outlet 14 is connected to the flue gas circulation fan 6 inlet through the heat exchanger 4; the flue gas circulation fan outlet is divided into two routes, the first route 11 is connected to the dehydration tank 10 inlet, and the second route 12 is discharged to the outside of the system; the dehydration tank 10 outlet pipeline is connected to the purge gas inlet of the air oxygen enrichment device 7.

[0056] Example 3

[0057] This embodiment describes the oxygen-enriched combustion gas supply method of the present invention in detail.

[0058] The working process of an oxygen-enriched combustion gas supply system and method provided by the present invention is as follows: air is pressurized by a combustion-supporting fan 3 and then enters an air oxygen-enriching device 7 for treatment. In the air oxygen-enriching device 7, oxygen has a higher membrane permeability and is enriched in the permeation channel, and nitrogen has a lower membrane permeability and is enriched in the residual channel. At the same time, a purge gas enters the permeation channel of the air oxygen-enriching device 7 from a purge gas inlet, and is discharged from the air oxygen-enriching device through the permeation channel together with the oxygen-enriched gas, and the nitrogen in the residual channel is discharged to the outside of the system 16; the oxygen-enriched gas discharged from the permeation channel of the air oxygen-enriching device 7 enters the combustion furnace 5 as combustion-supporting air after heat exchange to burn with the fuel, and the high-temperature flue gas 14 generated after combustion is subjected to heat exchange to recover heat, and is then pressurized by the flue gas circulation fan 6 and divided into two paths: the first path 11 enters the dehydration tank 10 for cooling and dehydration treatment, and then enters the air oxygen-enriching device 7 as a purge gas, and the second path 15 is discharged to the outside of the system for further carbon capture or recovery treatment.

[0059] Example 4

[0060] This embodiment provides a specific application case of an oxygen-enriched gas supply combustion system.

[0061] use Figure 1 The magnetic oxygen-enriched gas supply combustion system shown in the figure is used to carry out oxygen-enriched combustion treatment on a 10MW gas heating furnace of a certain enterprise. The fuel gas is natural gas and the air oxygen enrichment equipment adopts Figure 2 As shown, the membrane material is polymethylsiloxane / polycarbonate polymer nitrogen / oxygen separation membrane, the magnetic medium in the membrane separation component is 100μm iron-chromium alloy steel wool medium, the external magnetic field is an electromagnet, the external magnetic field strength is >5T, and the magnetic field gradient is >5000T / m.

[0062] After being pressurized by the combustion-supporting blower 3, the air enters the air oxygen enrichment device 7 for treatment. In the air oxygen enrichment device 7, oxygen has a higher membrane permeability and is enriched on the permeation side, and nitrogen has a lower membrane permeability and is enriched on the interception side. At the same time, CO2-rich flue gas (CO2 volume fraction of about 27%) enters the permeation side of the air oxygen enrichment device 7 from the purge gas inlet as a purge gas, and is discharged from the air oxygen enrichment device from the permeation side together with the oxygen-rich gas. At this time, the volume fractions of the components of the combustion-supporting air are: O2 is about 23%, N2 is about 53%, CO2 is about 15%, and the rest is water. The nitrogen on the interception side is discharged to the system 16; the oxygen-rich gas discharged from the permeation side of the air oxygen enrichment device 7 enters the combustion furnace 5 as combustion-supporting air after heat exchange and burns with the fuel. The high-temperature flue gas 14 generated after combustion is subjected to heat exchange to recover heat, and is then pressurized by the flue gas circulation fan 6 and divided into two paths: the first path accounts for 56% of the total flue gas volume and enters the dehydration tank 16 for cooling and dehydration treatment, and then enters the air oxygen enrichment device 7 as a purge gas. The second path is the residual flue gas discharge system. The CO2 volume concentration in the exhaust gas is about 27%, which can be further subjected to carbon capture or recovery treatment.

[0063] The above process uses membrane separation oxygen enrichment combined with flue gas circulation purge process optimization. Without modifying the original heating furnace burner, it reduces the flue gas generation, reduces the heat loss of flue gas, improves the thermal efficiency of the heating furnace, and can effectively control nitrogen oxide emissions. Compared with the air-assisted combustion process, the overall thermal efficiency of the combustion furnace is increased by more than 1%, the flue gas emission is reduced by about 60%, and the CO2 concentration in the flue gas is increased from about 10% to 27%, which is equivalent to a reduction of about 60% in the scale of subsequent carbon capture equipment, greatly reducing the cost of carbon capture and providing convenient conditions for the subsequent capture and recovery of CO2.

Claims

1. An air oxygen enrichment device, comprising an outer shell, a raw gas cavity, a residual gas cavity, an intermediate cavity, a membrane separation component and a magnetic field component; wherein: The raw gas cavity and the residual gas cavity are respectively located at two ends of the inner space of the outer shell; the middle cavity is located between the raw gas cavity and the residual gas cavity; The membrane separation component is arranged in the middle cavity; the membrane separation component is a hollow tube double-opening membrane, and the openings at both ends of the membrane separation component are respectively connected to the raw gas cavity and the residual gas cavity, dividing the middle cavity into a residual channel and a permeation channel; The hollow cavity of the membrane separation component forms a cutoff channel, and the cavities between the membrane separation components form a permeation channel; The raw gas cavity and the cut gas cavity are respectively provided with a raw gas inlet and a cut gas outlet; the two sides of the outer shell are respectively provided with a purge gas inlet and a permeate gas outlet, and the purge gas inlet and the permeate gas outlet are respectively connected to the permeate channel; The magnetic field components are arranged around or on both sides of the outer shell to form a magnetic field in the outer shell area; the permeation channels between the membrane separation components are filled with magnetic concentrating media.

2. The air oxygen enrichment device according to claim 1, characterized in that: The membrane separation components are arranged in multiple groups, and correspondingly form multiple groups of interception channels with the raw gas cavity and the interception gas cavity.

3. The air oxygen enrichment device according to claim 1, characterized in that: The feed gas inlet and the residue gas outlet are communicated with the residue channel of the membrane separation component, and the permeate gas outlet and the sweep gas inlet are connected with the permeate channel of the membrane separation component.

4. The air oxygen enrichment device according to claim 1, characterized in that: The magnetic field assembly is composed of multiple groups of magnets, and the magnets are permanent magnets, electromagnets or superconducting magnets.

5. The air oxygen enrichment device according to claim 1, characterized in that: The purge gas inlet and the permeate gas outlet are arranged at positions close to the two ends on both sides of the outer shell.

6. The air oxygen enrichment device according to claim 1, characterized in that: The tube wall of the membrane separation component is a membrane separation material, and the selectivity of the membrane separation material to O2 / N2 is greater than 2.

7. The air oxygen enrichment device according to claim 1, characterized in that: The magnetic concentrating medium is used to convert a uniform magnetic field into a high-gradient non-uniform magnetic field.

8. The air oxygen enrichment device according to claim 7, characterized in that: The magnetic concentrating medium is one or more of a ball medium, a tooth plate medium, a mesh medium, a rod medium and a steel wool medium.

9. The air oxygen enrichment device according to claim 1, 7 or 8, characterized in that: The material of the magnetic medium is one or more of pure iron, low carbon steel, ferrite magnetic stainless steel and iron-cobalt-neodymium-boron alloy.

10. A membrane oxygen-enriched combustion gas supply system, comprising the air oxygen-enriched equipment according to any one of claims 1 to 9.

11. The membrane oxygen-enriched combustion gas supply system according to claim 10, characterized in that: The system includes an air filter, a combustion-supporting fan, an air oxygen enrichment device, a heat exchanger, a combustion furnace, a flue gas circulation fan, and a dehydration tank; The combustion-supporting fan inlet is connected to the atmosphere through a filter; the combustion-supporting fan outlet 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 combustion air inlet of the gas furnace through a heat exchanger, and the residual gas outlet of the air oxygen enrichment device is connected to 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 to the outside of the system; The gas outlet of the dehydration tank is connected to the purge gas inlet of the air oxygen enrichment device through a pipeline.

12. The membrane oxygen-enriched combustion gas supply system according to claim 11, characterized in that: The dehydration tank is a cooling and dehydration gas-liquid separation tank, and a refrigerant heat extraction facility is arranged inside.

13. A membrane-based oxygen-enriched combustion gas supply method, wherein the oxygen-enriched combustion gas supply system according to any one of claims 10 to 12 is used.

14. The method according to claim 13, characterized in that The steps include: (1) After being pressurized by the combustion-supporting fan, the air enters the air oxygen enrichment device for treatment. In the air oxygen enrichment device, oxygen has a higher membrane permeability and is enriched in the permeation channel, while nitrogen has a lower membrane permeability and is enriched in the interception channel; At the same time, the purge gas enters the permeation channel of the air oxygen enrichment device through the purge gas inlet, and is discharged from the air oxygen enrichment device through the permeation channel together with the oxygen-enriched gas, and the nitrogen in the remaining channel is discharged out of the system; (2) The oxygen-enriched gas discharged from the permeation channel of the air oxygen enrichment device in step (1) enters the combustion furnace as combustion-supporting air after heat exchange and burns with the fuel. The high-temperature flue gas generated after combustion is subjected to heat exchange to recover heat, and then is pressurized by the flue gas circulation fan and divided into two paths: the first path enters the dehydration tank for cooling and dehydration treatment, and the second path is discharged from the system; (3) The low-temperature flue gas treated in the dehydration tank in step (2) is used as purge gas and enters the air oxygen enrichment device through the purge gas inlet.

15. The method according to claim 14, characterized in that In step (1), an air filter is arranged before the combustion-supporting blower to filter impurities in the air.

16. The method according to claim 14, characterized in that The flue gas described in step (2) is CO2-rich flue gas, and the volume concentration of CO2 in the flue gas is higher than 20%.

17. The method according to claim 14, characterized in that The volume concentration of O2 in the exhaust gas from the permeation channel of the air oxygen enrichment device in step (1) is ≥21%.

18. The method according to claim 14, characterized in that The temperature of the dehydration tank in step (2) is 10-60°C.

19. The method according to claim 14, characterized in that In step (2), the high-temperature flue gas is divided into two paths after being pressurized by the circulating fan, the first path accounts for 10% to 60% of the total flue gas, and the second path accounts for 40% to 90% of the total flue gas.

20. The method according to claim 14, characterized in that In step (2), the gas discharged from the second path of the system is further subjected to carbon capture or recovery treatment.

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