Front and back wall opposed swirl coal-ammonia integrated low nox burner and control method

Abstract

The application discloses a front and back wall butt-jetting cyclone type coal-ammonia integrated low-NO x The application discloses a combustor and a control method, the combustor is used for being installed on a front wall and a back wall of a furnace body, the combustor adopts a coaxial multi-ring sleeve structure and comprises a center air pipe, a primary air pipe, an ammonia pipe, an inner secondary air pipe and an outer secondary air pipe which are sequentially arranged from inside to outside; the outer secondary air pipe is sleeved outside the inner secondary air pipe and is provided with a high-speed air flow channel, the high-speed air flow channel is arranged in a spaced mode with the inner secondary air pipe, a spray plate is arranged on a spray-out side cover of the outer secondary air pipe, a plurality of spray holes which are in communication with the high-speed air flow channel are arranged on the spray plate, and a central axis of each spray hole is arranged in an acute angle mode with a central axis of the combustor. x The combustor makes the boiler stably run in a wide load range, has a quick load change capacity, simultaneously reduces generation of nitrogen oxides, and is suitable for low-carbon flexible reconstruction of active coal power units.

Description

Technical Field

[0001] This invention relates to the field of clean combustion and thermal power generation technology, and in particular to a front and rear wall opposed-wall swirl-type integrated coal-ammonia low NOx system. x Burners and control methods. Background Technology

[0002] To achieve the "dual carbon" goal, existing coal-fired power plants urgently need low-carbon and flexibility retrofitting. Blending with zero-carbon fuel ammonia is one effective approach, but it faces significant challenges, as ammonia combustion easily generates large amounts of nitrogen oxides. Among related technologies, some solutions use separate ammonia spray guns outside the burner, but the amount of nitrogen oxides generated remains high. Other solutions attempt to premix ammonia with pulverized coal, but this exacerbates localized high temperatures, leading to increased NOx emissions. x The generation rate has increased. Therefore, improvements are needed. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one object of this invention is to propose a front and rear wall counter-flow swirl-type integrated coal-ammonia low-NOx system. x The burner produces less nitrogen oxides during combustion.

[0004] The present invention also proposes a control method for the above-mentioned burner.

[0005] According to embodiments of the present invention, a front and rear wall counter-flow swirl-type coal-ammonia integrated low NO x The burner is used to be installed on the front and rear walls of the furnace body. The burner adopts a coaxial multi-ring sleeve structure and includes a central air duct, a primary air duct, an ammonia gas duct, an inner secondary air duct, and an outer secondary air duct arranged sequentially from the inside to the outside. The central air duct is used to introduce cooling air. The primary air duct is sleeved outside the central air duct and defines a pulverized coal flow channel between them. The outlet of the primary air duct is equipped with a flame stabilizing structure. The ammonia pipe is sleeved outside the primary air duct and defines an ammonia flow channel between the ammonia pipe and the primary air duct. The outlet end of the ammonia pipe is provided with a first adjustable swirling device, which is located inside the ammonia flow channel. The inner secondary air duct is sleeved outside the ammonia pipe and defines a main air flow channel between the two. The outlet end of the inner secondary air duct is provided with a second adjustable swirl device, which is located inside the main air flow channel. The external secondary air duct is sleeved outside the internal secondary air duct and is provided with a high-speed air flow channel. The high-speed air flow channel is spaced apart from the internal secondary air duct. The ejection side cover of the external secondary air duct is provided with an injection plate. The injection plate is provided with multiple nozzles communicating with the high-speed air flow channel. The multiple nozzles are spaced apart along the circumference of the external secondary air duct, and the central axis of each nozzle is set at an acute angle to the central axis of the burner.

[0006] According to embodiments of the present invention, a front and rear wall counter-flow swirl-type coal-ammonia integrated low NO x The burner, employing a multi-ring sleeve structure and incorporating adjustable swirl devices in the ammonia pipe and internal secondary air duct, creates a pulverized coal-rich fuel reduction zone and an ammonia cracking reduction zone at the burner outlet, effectively suppressing NO. x Simultaneously, by installing a spray plate with nozzles at a specific angle at the end of the external secondary air duct, a high-speed air turbulence combustion zone is formed, ensuring the complete combustion of residual ammonia and CO, preventing ammonia escape, and achieving efficient and clean combustion. This burner has a compact structure and can meet the needs of flexible low-carbon retrofitting of coal-fired power units.

[0007] According to some embodiments of the present invention, the angle between the central axis of the nozzle and the central axis of the burner is between 40° and 55°; and / or, the flow area of ​​the high-speed airflow channel is smaller than the flow area of ​​the main airflow channel.

[0008] According to some embodiments of the present invention, the external secondary air duct is sleeved on the outlet end of the internal secondary air duct. The external secondary air duct includes an inlet section and an injection section. The inlet section extends along the axial direction of the burner. In the direction from the inlet section to the injection section, the injection section extends obliquely toward the central axis of the burner. The outlet side of the injection section is covered with the injection plate.

[0009] According to some embodiments of the present invention, the inner peripheral wall of the injection section is provided with an annular pressure boosting structure, the pressure boosting structure being a protruding structure extending circumferentially along the injection section, and the inner peripheral side of the pressure boosting structure defining a pressure boosting channel.

[0010] According to some embodiments of the present invention, a plurality of the nozzles are evenly spaced along the circumference of the external secondary air duct; and / or, the flame stabilizing structure includes a plurality of flame stabilizing teeth, which are disposed at the outlet edge of the primary air duct and spaced along the circumference of the primary air duct.

[0011] According to some embodiments of the present invention, the inner peripheral wall of the primary air duct is provided with an annular concentration structure, the concentration structure being a protruding structure extending circumferentially along the primary air duct, and the inner peripheral side of the concentration structure defining a concentration channel.

[0012] According to some embodiments of the present invention, both the first adjustable swirl device and the second adjustable swirl device include axially adjustable swirl blades.

[0013] The burner control method according to a second aspect embodiment of the present invention includes: Low-load stable combustion control: When the furnace body equipped with the burner is in a low-load operation state, the blade angle of the second adjustable swirl device is increased to enhance the swirl intensity of the internal secondary air; Rapid response control for variable load: During the unit's load change process, the ammonia supply to the ammonia flow channel is adjusted first, and the air volume of the high-speed air flow channel is adjusted simultaneously; wherein, the load change process includes the process of changing the number of burners in operation or the fuel quantity of a single burner.

[0014] According to the burner control method of this embodiment, by increasing the blade angle of the second adjustable swirl device during low-load operation, the swirl intensity of the internal secondary air is enhanced to maintain the central high-temperature recirculation zone and reduce the temperature loss in the central high-temperature recirculation zone. This allows the boiler to maintain stable combustion without oil injection under extremely low load, significantly reducing the minimum load compared to the conventional method. This allows fewer burners to operate while supporting boiler operation, which is beneficial for energy saving and consumption reduction. Furthermore, during load changes, the ammonia supply to the ammonia flow channel is adjusted first, and the air volume of the high-speed air flow channel is adjusted simultaneously. Because the response speed of the ammonia supply and the air volume adjustment of the high-speed air flow channel is relatively fast, the overall load change rate of the burner unit is greatly improved.

[0015] According to some embodiments of the present invention, the ammonia blending ratio is increased under low load to assist in stable combustion.

[0016] According to some embodiments of the present invention, after prioritizing the adjustment of the ammonia supply to the ammonia flow channel and the air volume of the high-speed air flow channel, the coal powder supply to the coal powder flow channel is then adjusted accordingly.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a front and rear wall opposed-flow swirl coal-ammonia integrated low NO2 type according to some embodiments of the present invention. x Cross-sectional view of the burner; Figure 2 yes Figure 1 Enlarged view of point A in the middle; Figure 3This is a front and rear wall opposed-flow swirl coal-ammonia integrated low NO2 type according to some embodiments of the present invention. x A partial front view of the burner.

[0019] Figure label: 100. Burner; 10. Central air duct; 20. Primary air duct; 21. Pulverized coal flow channel; 22. Flame stabilizing structure; 221. Flame stabilizing teeth; 23. Concentrating structure; 30. Ammonia gas pipe; 31. Ammonia gas flow channel; 32. First adjustable cyclone device; 40. Internal secondary air duct; 41. Main airflow channel; 42. Second adjustable swirl device; 50. External secondary air duct; 501. Inlet section; 502. Injection section; 51. High-speed airflow channel; 52. Injection plate; 53. Injection hole; 54. Pressurization structure; 55. Pressurization channel. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] The following is for reference. Figures 1-3 Description of the front and rear wall opposed-flow swirl coal-ammonia integrated low NO2 type according to embodiments of the present invention x Burner 100.

[0022] refer to Figures 1-3 According to an embodiment of the present invention, a front and rear wall opposed swirl-type coal-ammonia integrated low NO... x The burner 100 is used to install on the front and rear walls of the furnace body. The burner 100 adopts a coaxial multi-ring sleeve structure and includes a central air duct 10, a primary air duct 20, an ammonia gas duct 30, an inner secondary air duct 40, and an outer secondary air duct 50 arranged sequentially from the inside to the outside.

[0023] The central air duct 10 is used to introduce cooling air. The primary air duct 20 is sleeved outside the central air duct 10, and a pulverized coal flow channel 21 is defined between the primary air duct 20 and the central air duct 10. The outlet of the primary air duct 20 is provided with a flame stabilizing structure 22.

[0024] For example, when the flame root of the burner 100 is overheated, a small amount of cooling air can be introduced into the central air duct 10 for cooling; when the burner 100 is burning stably, a small amount of cooling air can also be introduced into the central air duct 10 to promote the formation of the central high-temperature recirculation zone by generating a temperature difference.

[0025] The ammonia pipe 30 is sleeved outside the primary air pipe 20, and the ammonia pipe 30 and the primary air pipe 20 define an ammonia flow channel 31. The outlet end of the ammonia pipe 30 is provided with a first adjustable swirling device 32, which is located inside the ammonia flow channel 31.

[0026] The inner secondary air duct 40 is fitted outside the ammonia pipe 30, and the main air flow channel 41 is defined between the inner secondary air duct 40 and the ammonia pipe 30. The outlet end of the inner secondary air duct 40 is provided with a second adjustable swirl device 42, which is located inside the main air flow channel 41.

[0027] An external secondary air duct 50 is fitted outside an internal secondary air duct 40, and the external secondary air duct 50 is provided with a high-speed air flow channel 51. The high-speed air flow channel 51 is spaced apart from the internal secondary air duct 40. The ejection side cover of the external secondary air duct 50 is provided with an injection plate 52. The injection plate 52 is provided with multiple nozzles 53 that communicate with the high-speed air flow channel 51. The multiple nozzles 53 are spaced apart along the circumference of the external secondary air duct 50, and the central axis of each nozzle 53 is set at an acute angle to the central axis of the burner 100.

[0028] For example, the angle between the central axis of the nozzle 53 and the central axis of the burner 100 can be referenced to α in the attached figure.

[0029] By including a central air duct 10, a primary air duct 20, an ammonia gas duct 30, an inner secondary air duct 40, and an outer secondary air duct 50 arranged sequentially from the inside to the outside, the central air duct 10 is used to introduce cooling air, and a second adjustable swirl device 42 is provided at the outlet end of the inner secondary air duct 40. This facilitates the establishment of a central high-temperature recirculation zone, reduces heat loss by reducing airflow outwards, reduces ammonia gas escape, creates a low-oxygen environment, and can also sequentially form three zones from the outlet of the burner 100 to the furnace body: a high-temperature reduction zone for pulverized coal rich fuel, an ammonia gas cracking and deep reduction zone, and a high-speed air turbulence burnout zone.

[0030] Among them, the fuel-rich high-temperature reduction zone and the ammonia cracking and deep reduction zone are low-oxygen environments, while the high-speed air turbulence burnout zone is a high-oxygen environment.

[0031] In particular, the central high-temperature recirculation zone formed by the strong swirling secondary air in the high-temperature reduction zone of pulverized coal ignites dense-phase pulverized coal, which can generate a strong reducing atmosphere under low-oxygen conditions, suppressing fuel-type NO. x The ammonia gas ejected from the first adjustable cyclone device 32 in the ammonia cracking and deep reduction zone is heated and cracked around the pulverized coal flame. The cracking products (such as H2 and NH2) can further reduce NO diffused from the central high-temperature reflux zone. x Meanwhile, the endothermic reaction of pyrolysis helps to moderate the flame temperature and suppress thermal NO. xThe high-speed airflow ejected from the high-speed air jet array cuts into the flue gas generated in the first two zones at a sharp angle. While achieving rapid separation of the reduction zone and the burnout zone in physical space, it ensures instantaneous and complete combustion of unburned substances such as residual ammonia and CO through extremely strong turbulence, preventing ammonia escape and improving combustion efficiency, while reducing the generation of nitrogen oxides.

[0032] According to embodiments of the present invention, a front and rear wall counter-flow swirl-type coal-ammonia integrated low NO x The burner 100, by employing a multi-ring sleeve structure and installing adjustable swirl devices in the ammonia pipe 30 and the inner secondary air pipe 40 respectively, forms a pulverized coal-rich fuel reduction zone and an ammonia cracking reduction zone at the burner outlet, effectively suppressing NO. x Simultaneously, by setting an injection plate 52 with nozzles at a specific angle at the end of the external secondary air duct 50, a high-speed air turbulence combustion zone is formed, ensuring the complete combustion of residual ammonia and CO, preventing ammonia escape, and achieving efficient and clean combustion. This burner 100 has a compact structure and can meet the needs of flexible low-carbon retrofitting of coal-fired power units.

[0033] refer to Figure 1 According to some embodiments of the present invention, the angle between the central axis of the nozzle 53 and the central axis of the burner 100 is between 40° and 55°.

[0034] For example, the angle between the central axis of the nozzle 53 and the central axis of the burner 100 can be 40°, 41°, 42°, 43°, 44°, 45°, 46°, 47°, 48°, 49°, 50°, 51°, 52°, 53°, 54°, 55°, etc. If the angle between the central axis of the nozzle 53 and the central axis of the burner 100 is too large, the high-speed air jet will have difficulty cutting into the flue gas. If the angle between the central axis of the nozzle 53 and the central axis of the burner 100 is too small, the central high-temperature recirculation zone will be too small, which is not conducive to the stable combustion of ammonia and pulverized coal.

[0035] By making the angle between the central axis of the nozzle 53 and the central axis of the burner 100 between 40° and 55°, high-speed air can be mixed with flue gas in a high-speed cutting manner, thereby better achieving the purpose of fully mixing unburned nitrogen oxides, carbon monoxide and ammonia to make them burn evenly.

[0036] refer to Figure 1 According to some embodiments of the present invention, the flow area of ​​the high-speed airflow channel 51 is smaller than that of the main airflow channel 41.

[0037] By making the flow area of ​​the high-speed airflow channel 51 smaller than that of the main airflow channel 41, it is beneficial to make the airflow velocity ejected from the high-speed airflow channel 51 higher than that ejected from the main airflow channel 41. This allows the airflow ejected from the high-speed airflow channel 51 to mix with the flue gas in a high-speed cutting manner, creating a high-speed air turbulence combustion zone in front of the burner 100. This enables unburned substances such as residual ammonia and CO to burn instantly and completely, preventing ammonia escape and ensuring combustion efficiency and the generation of nitrogen oxides.

[0038] refer to Figures 1-2 According to some embodiments of the present invention, an external secondary air duct 50 is sleeved on the outlet end of an internal secondary air duct 40. The external secondary air duct 50 includes an inlet section 501 and an injection section 502. The inlet section 501 extends along the axial direction of the burner 100. In the direction from the inlet section 501 to the injection section 502, the injection section 502 extends obliquely toward the direction close to the central axis of the burner 100. The outlet side of the injection section 502 is covered with an injection plate 52.

[0039] By extending the injection section 502 at an angle toward the central axis of the burner 100 in the direction from the inlet section 501 to the injection section 502, it is advantageous for high-speed air to enter the flue gas in a straight line and at an angle to the central axis of the burner 100. By providing an injection plate 52 on the outlet side cover of the injection section 502, high-speed gas is ejected along the nozzle 53, which is beneficial for pressurizing the high-speed gas and increasing the flow rate of the high-speed gas.

[0040] refer to Figure 2 According to some embodiments of the present invention, the inner peripheral wall of the injection section 502 is provided with an annular pressure boosting structure 54, the pressure boosting structure 54 is a protruding structure extending circumferentially along the injection section 502, and the inner peripheral side of the pressure boosting structure 54 defines a pressure boosting channel 55.

[0041] For example, the protrusion structure can be a streamlined protrusion that is thicker in the middle and thinner on both sides.

[0042] By providing an annular pressure boosting structure 54 on the inner peripheral wall of the injection section 502, which is similar to an annular narrow-diameter nozzle, the airflow velocity increases and the static pressure decreases when flowing through the pressure boosting channel 55, thereby obtaining a higher dynamic pressure head before entering the injection plate 52, ensuring that the high-speed air ejected from the nozzle 53 has sufficient momentum to penetrate and strongly mix the flue gas.

[0043] refer to Figure 3 According to some embodiments of the present invention, a plurality of nozzles 53 are evenly spaced along the circumference of the external secondary air duct 50.

[0044] By arranging multiple nozzles 53 at uniform intervals along the circumference of the external secondary air duct 50, it is beneficial to mix the high-speed gas and flue gas more evenly, and to burn unburned substances such as residual ammonia and CO in the high-speed air turbulence burnout zone more evenly, thereby reducing the generation of nitrogen oxides.

[0045] refer to Figure 3 According to some embodiments of the present invention, the flame stabilizing structure 22 includes a plurality of flame stabilizing teeth 221, which are disposed at the outlet edge of the primary air duct 20 and are spaced apart circumferentially along the primary air duct 20. By including a plurality of flame stabilizing teeth 221 in the flame stabilizing structure 22 and disposing of them at the outlet edge of the primary air duct 20, airflow turbulence can be enhanced, the mixing and reaction rate of pulverized coal and ammonia can be accelerated, and combustion can be stabilized.

[0046] refer to Figure 1 According to some embodiments of the present invention, the inner peripheral wall of the primary air duct 20 is provided with an annular concentration structure 23. When the coal powder gas flows through the concentration structure 23, due to the change in the flow channel cross section, some coal powder particles are attracted to the inner wall of the primary air duct 20 by inertia, thereby forming a coal powder concentration distribution with a high concentration outside and a low concentration inside at the outlet. The high concentration coal powder area is more easily ignited by the central high temperature recirculation zone, which enhances the ignition stability.

[0047] refer to Figure 1 According to some embodiments of the present invention, both the first adjustable swirl device 32 and the second adjustable swirl device 42 include axially adjustable swirl blades.

[0048] Among them, the axially adjustable swirl blade is a blade whose included angle with the axial direction of the burner 100 is adjustable.

[0049] By including axially adjustable swirl blades in both the first adjustable swirl device 32 and the second adjustable swirl device 42, the angle between the ammonia flowing out of the ammonia pipe 30 and the air flowing out of the inner secondary air pipe 40 and the axial direction of the burner 100 can be adjusted, thereby adjusting the swirl intensity of ammonia and air. The airflow adjustment is highly flexible in different operating modes, which is beneficial to the stable combustion of ammonia.

[0050] A control method for a burner 100 according to a second aspect embodiment of the present invention includes: Low-load stable combustion control: When the furnace body equipped with the burner 100 is in a low-load operation state, the blade angle of the second adjustable swirl device 42 is increased to enhance the swirl intensity of the internal secondary air. Rapid response control for variable load: During the load change process of the unit, the ammonia supply to the ammonia flow channel 31 is adjusted first, and the air volume of the high-speed air flow channel 51 is adjusted simultaneously; wherein, the load change process includes the process of changing the number of burners 100 in operation or the process of changing the fuel quantity of a single burner 100.

[0051] Low-load operation refers to the operation of 30%-50% of all burners 100 installed in the furnace body, and the unit refers to all burners 100 installed in the furnace body.

[0052] The blade angle of the second adjustable swirl device 42 is the angle between the blade and the axial direction of the burner 100.

[0053] For example, when the blade angle of the second adjustable swirl device 42 increases, the angle between the airflow from the inner secondary air duct 40 and the axial direction of the burner 100 increases, and the swirl intensity of the inner secondary air becomes stronger; when the blade angle of the second adjustable swirl device 42 decreases, the angle between the airflow from the inner secondary air duct 40 and the axial direction of the burner 100 decreases, and the swirl intensity of the inner secondary air becomes weaker.

[0054] According to the control method of the burner 100 in this embodiment, by increasing the blade angle of the second adjustable swirl device 42 during low-load operation, the swirl intensity of the internal secondary air is enhanced to maintain the central high-temperature recirculation zone and reduce the temperature loss of the central high-temperature recirculation zone. This allows the boiler to maintain stable combustion without oil injection under extremely low load, and the minimum load is significantly reduced compared to the conventional method. This allows fewer burners 100 to operate while supporting boiler operation, which is beneficial for energy saving and consumption reduction. Furthermore, during load change, the ammonia supply to the ammonia flow channel 31 is adjusted first, and the air volume of the high-speed air flow channel 51 is adjusted simultaneously. Since the response speed of the ammonia supply and the air volume adjustment of the high-speed air flow channel 51 is relatively fast, the overall load change rate of the burner 100 unit is greatly improved.

[0055] According to some embodiments of the present invention, the ammonia blending ratio is increased under low load to assist in stable combustion.

[0056] By increasing the ammonia blending ratio under low load to assist in stable combustion, it is beneficial to maintain stable combustion of the boiler without oil injection under extremely low load. The minimum load is significantly reduced compared to the conventional method, allowing fewer burners to operate to support boiler operation.

[0057] According to some embodiments of the present invention, after prioritizing the adjustment of the ammonia supply to the ammonia flow channel 31 and the air volume of the high-speed air flow channel 51, the coal powder supply to the coal powder flow channel 21 is then adjusted accordingly.

[0058] Among them, matching adjustment is to match the coal powder supply with the ammonia supply.

[0059] For example, the coal powder supply can be adjusted by controlling the amount of coal added to the coal feeder.

[0060] For example, after adjusting the ammonia supply to the ammonia flow channel 31 and the air volume of the high-speed air flow channel 51, if the coal powder supply is insufficient, the amount of coal added to the coal feeder will be reduced; if the coal powder supply is excessive, the amount of coal added to the coal feeder will be increased. This can prevent ammonia escape caused by excessive ammonia and also prevent the waste of coal powder.

[0061] Since the response speed of ammonia supply and airflow regulation of high-speed airflow channel 51 is relatively fast, while the response speed of pulverized coal supply is relatively slow, the overall load change rate of burner 100 can be improved by prioritizing the adjustment of ammonia supply to ammonia flow channel 31 and airflow of high-speed airflow channel 51, and then matching and adjusting the pulverized coal supply to pulverized coal flow channel 21.

[0062] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0063] In the description of this invention, "first feature" and "second feature" may include one or more of the features.

[0064] In the description of this invention, "a plurality of" means two or more.

[0065] In the description of this invention, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or it may include the first and second features not being in direct contact but being in contact through another feature between them.

[0066] In the description of this invention, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicating that the first feature is at a higher horizontal level than the second feature.

[0067] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0068] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A front and rear wall opposed-wall swirl-type coal-ammonia integrated low NOx x The burner is characterized in that, The burner is used to be installed on the front and rear walls of the furnace body. The burner adopts a coaxial multi-ring sleeve structure and includes a central air duct, a primary air duct, an ammonia gas duct, an inner secondary air duct, and an outer secondary air duct arranged sequentially from the inside to the outside. The central air duct is used to introduce cooling air. The primary air duct is sleeved outside the central air duct and defines a pulverized coal flow channel between them. The outlet of the primary air duct is equipped with a flame stabilizing structure. The ammonia pipe is sleeved outside the primary air duct and defines an ammonia flow channel between the ammonia pipe and the primary air duct. The outlet end of the ammonia pipe is provided with a first adjustable swirling device, which is located inside the ammonia flow channel. The inner secondary air duct is sleeved outside the ammonia pipe and defines a main air flow channel between the two. The outlet end of the inner secondary air duct is provided with a second adjustable swirl device, which is located inside the main air flow channel. The external secondary air duct is sleeved outside the internal secondary air duct and is provided with a high-speed air flow channel. The high-speed air flow channel is spaced apart from the internal secondary air duct. The ejection side cover of the external secondary air duct is provided with an injection plate. The injection plate is provided with multiple nozzles communicating with the high-speed air flow channel. The multiple nozzles are spaced apart along the circumference of the external secondary air duct, and the central axis of each nozzle is set at an acute angle to the central axis of the burner.

2. The front and rear wall opposed-flow swirl coal-ammonia integrated low NOₓ type according to claim 1 x The burner is characterized in that, The angle between the central axis of the nozzle and the central axis of the burner is between 40° and 55°. And / or, the flow area of ​​the high-speed airflow channel is smaller than the flow area of ​​the main airflow channel.

3. The front and rear wall opposed-flow swirl coal-ammonia integrated low NOₓ type according to claim 1 x The burner is characterized in that, The external secondary air duct is sleeved on the outlet end of the internal secondary air duct. The external secondary air duct includes an inlet section and an injection section. The inlet section extends along the axial direction of the burner. In the direction from the inlet section to the injection section, the injection section extends obliquely toward the central axis of the burner. The injection plate is provided on the outlet side of the injection section.

4. The front and rear wall opposed-flow swirl coal-ammonia integrated low NOₓ type according to claim 3 x The burner is characterized in that, The inner peripheral wall of the injection section is provided with an annular pressure boosting structure, which is a protruding structure extending circumferentially along the injection section, and the inner peripheral side of the pressure boosting structure defines a pressure boosting channel.

5. The front and rear wall opposed-flow swirl coal-ammonia integrated low NOₓ type according to claim 1 x The burner is characterized in that, The multiple nozzles are evenly spaced along the circumference of the external secondary air duct; And / or, the flame stabilizing structure includes a plurality of flame stabilizing teeth, which are disposed at the outlet edge of the primary air duct and spaced apart circumferentially along the primary air duct.

6. The front and rear wall opposed-flow swirl coal-ammonia integrated low NO₂ type as described in claim 1 x The burner is characterized in that, The inner circumferential wall of the primary air duct is provided with an annular concentration structure, which is a protruding structure extending circumferentially along the primary air duct, and the inner circumferential side of the concentration structure defines a concentration channel.

7. The front and rear wall opposed-flow swirl coal-ammonia integrated low NO₂ type as described in claim 1 x The burner is characterized in that, Both the first adjustable swirling device and the second adjustable swirling device include axially adjustable swirling blades.

8. A control method for a burner according to any one of claims 1-7, characterized in that, include: Low-load stable combustion control: When the furnace body equipped with the burner is in a low-load operation state, the blade angle of the second adjustable swirl device is increased to enhance the swirl intensity of the internal secondary air; Rapid response control for variable load: During the unit's load change process, the ammonia supply to the ammonia flow channel is adjusted first, and the air volume of the high-speed air flow channel is adjusted simultaneously; wherein, the load change process includes the process of changing the number of burners in operation or the fuel quantity of a single burner.

9. The burner control method according to claim 8, characterized in that, Increase the ammonia blending ratio under low load to assist in stable combustion.

10. The burner control method according to claim 8, characterized in that, After prioritizing the adjustment of the ammonia supply to the ammonia flow channel and the airflow to the high-speed air flow channel, the coal powder supply to the coal powder flow channel is then adjusted accordingly.

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