Turbulent burner for ammonia-coal mixed combustion and using method thereof

Abstract

The invention discloses a turbulent burner for mixed combustion of ammonia and coal. The turbulent burner comprises a first cylinder, a second cylinder and a third cylinder, a pulverized coal airflow channel is formed in an inner cavity of the first cylinder; an ammonia gas channel is formed between the first cylinder and the second cylinder; a secondary air channel is formed between the second cylinder and the third cylinder; an inner cavity of the first cylinder is divided into four sections from front to back, namely a first steady flow section, a divergent section, a second steady flow section and a tapered section in sequence, the first steady flow section and the second steady flow section are cylindrical, the divergent section and the tapered section are circular truncated cone-shaped, and the diameter of the front end of the divergent section is large; the front end of the reducing section is small in diameter; a bluff body with a cylindrical front end and a circular truncated cone rear end is arranged in the first cylinder, one part of the bluff body rear end is located inside and outside the divergent section, and the other part is located in the first steady flow section; rotational flow blades are connected between the inner wall of the first cylinder and the outer wall of the blunt body; a plurality of guide plates are evenly distributed at the front end of the second cylinder in the circumferential direction. The method is suitable for the working condition with the small ammonia mixing proportion, and the transition effect of the coal-fired boiler from pure coal combustion to high-proportion ammonia-doped combustion is mainly achieved.

Description

Technical Field

[0001] The invention relates to a burner, and in particular to a swirl burner for ammonia-coal mixed combustion and a use method thereof. Background Art

[0002] At present, in recent years, coal has always occupied the main position in my country's energy consumption. my country's energy structure determines that for a long time in the future, my country's energy source will still be coal-fired power generation. However, the CO2 produced by coal combustion has led to a series of climate problems, including intensified droughts, melting glaciers, frequent wildfires, and so on. Therefore, my country's power industry urgently needs to transform to clean and low-carbon, and achieve carbon emission reduction, especially reducing carbon emission reduction from coal-fired units, which is the key to my country's realization of the "dual carbon" goal. The one-size-fits-all elimination of all coal-fired units will cause huge economic waste and trigger a series of social and livelihood issues. The use of zero-carbon energy substitution can achieve carbon emission reduction while retaining the original units.

[0003] As an ideal zero-carbon energy source, hydrogen has received widespread attention. However, its safety cannot be resolved in the short term. It is difficult to transport on a large scale, has high storage costs, and has high liquefaction pressure. Compared with hydrogen, ammonia, as an ideal zero-carbon energy source, has high safety, can be transported on a large scale, has lower storage costs, and has a higher volumetric energy density. Therefore, ammonia-coal co-firing will be one of the important development directions for the green and low-carbon transformation of coal-fired power plants. However, ammonia still faces some problems when burned as the main fuel. On the one hand, the fuel properties between ammonia and pulverized coal are very different. Moreover, during the co-firing process, ammonia will compete with pulverized coal for O2, affecting the ignition, stable combustion, and combustion of the pulverized coal flame. On the other hand, ammonia contains a large amount of nitrogen, which may lead to NO at the furnace outlet. x Emissions are rising rapidly. Coal-fired power plants are facing strict emission control standards for air pollutants.

[0004] Compared with gaseous fuel such as ammonia, pulverized coal as a solid fuel is more difficult to burn, especially under the condition of low ammonia mixing ratio. More attention should be paid to how to ensure the stable combustion of pulverized coal after ammonia mixing and the subsequent NO x Control. Generally speaking, the burner, as the core part of the combustion system, controls the fuel / air mixing process and is the key equipment to achieve fuel ignition and stable combustion. For ammonia-coal co-combustion, the local oxygen concentration distribution and the initial reaction environment of ammonia can be flexibly controlled by designing the burner structure, and the fuel / air mixing process can be reasonably organized to improve the fuel combustion characteristics and reduce NO x This is of great significance for achieving clean and low-carbon combustion in coal-fired power plants by adding ammonia. Summary of the invention

[0005] The present invention provides a swirl burner for ammonia-coal co-firing and a method of using the same in order to solve the technical problems existing in the known technology.

[0006] The technical solution adopted by the present invention to solve the technical problems existing in the known technology is:

[0007] A swirl burner for ammonia-coal mixed combustion comprises first to third cylinders which are sleeved in sequence from the inside to the outside; the inner cavity of the first cylinder forms a coal powder airflow channel; the cavity between the first and second cylinders forms an ammonia gas channel; the cavity between the second and third cylinders forms a secondary air channel; the inner cavity of the first cylinder is divided into four sections from front to back, which are the first steady flow section, the gradually expanding section, the second steady flow section and the gradually contracting section, the first and second steady flow sections are cylindrical, the gradually expanding section and the gradually contracting section are truncated cone-shaped, the front end diameter of the gradually expanding section is larger than the rear end diameter diameter; the front end diameter of the tapering section is smaller than the rear end diameter; a blunt body is arranged in the first cylinder, the front end of the blunt body is a cylinder and the rear end is a truncated cone; except for a part of the rear end of the blunt body located inside and outside the gradually expanding section, the rest of the blunt body is located in the first steady flow section; a swirl blade is connected between the inner wall of the first cylinder and the outer wall of the blunt body; a plurality of guide plates with adjustable outward opening angles are uniformly distributed along the circumferential direction at the front end of the second cylinder; the outward opening angle of the guide plates is adjusted in the range of 0 to 30 degrees, and the plurality of guide plates are surrounded to form a trumpet shape.

[0008] Furthermore, the front end surface of the third cylinder is 3 to 7 mm longer than the front end surface of the second cylinder in the axial direction.

[0009] Furthermore, the outer edge of the front end surface of the bluff body is provided with grooves evenly distributed along the circumferential direction, and the plurality of grooves form a flame stabilizing ring.

[0010] Furthermore, a plurality of axial through holes are evenly distributed in the circumferential direction in the wall of the first cylinder; the rear ends of the through holes are connected to the water supply device.

[0011] Furthermore, the length of the first cylinder is 80-100 mm, the inner diameter of the first steady flow section is 26-35 mm, and the length is 40-50 mm; the inner diameter of the second steady flow section is 15-24 mm; the length is 40-50 mm; the length of the gradually expanding section is 15-18 mm; and the length of the gradually contracting section is 10-12 mm.

[0012] Furthermore, the maximum diameter of the truncated cone in the bluff body is 14-18 mm, and the minimum diameter is 6-10 mm; the length of the cylindrical part of the bluff body is 20-25 mm, and the length of the truncated cone part of the bluff body is 12-16 mm.

[0013] Furthermore, the gap between the first and second cylinders is 0.6-1 mm; the gap between the second and third cylinders is 0.8-1.2 mm.

[0014] Furthermore, the guide plate has a length of 4 to 6 mm along the axial direction of the swirl burner and a thickness of 0.5 to 0.8 mm.

[0015] The present invention also provides several methods for using the above-mentioned swirl burner for ammonia-coal mixed combustion, and uses the swirl burner as a pure coal burner and / or an ammonia-coal mixed burner;

[0016] When the swirl burner is used as a pure coal burner, the method comprises the following steps:

[0017] The pulverized coal mixed primary air is sprayed into the pulverized coal airflow channel from the gradually contracting section, and passes through the second steady flow section, the gradually expanding section, and the first steady flow section in sequence, and is separated into two swirls of thick and thin, which suck in the high-temperature flue gas in the furnace, causing the pulverized coal to ignite and burn; then, the remaining air is divided into internal and external secondary air, and the internal secondary air is first sprayed into the furnace through the ammonia channel; the internal secondary air contacts and burns with the concentrated pulverized coal airflow at the outlet of the pulverized coal airflow channel; then, the expansion angle of the guide plate is adjusted to increase the size of the central recirculation zone, so that the primary air pulverized coal flow is heated; finally, the external secondary air is sprayed into the furnace through the secondary air channel to achieve complete combustion of the pulverized coal;

[0018] When the swirl burner is used as an ammonia-coal mixed burner, the method comprises the following steps:

[0019] The pulverized coal mixed with primary air is injected from the gradually contracting section of the pulverized coal airflow channel, and passes through the second steady flow section, the gradually expanding section, and the first steady flow section in sequence, and is separated into two swirls of thick and thin, which suck in the high-temperature flue gas in the furnace, causing the pulverized coal to ignite and burn; subsequently, water is sprayed into the furnace to increase the concentration of H and OH free radicals in the environment; then, all the ammonia is directly injected into the furnace from the ammonia channel at one time; the expansion angle of the guide plate is adjusted to prevent the ammonia from combining with the secondary air too early in the early stage of combustion and being oxidized into NO x ; Finally, the secondary air is sprayed into the furnace through the secondary air channel to achieve complete combustion of coal powder and ammonia.

[0020] Furthermore, when the swirl burner is used as an ammonia-coal mixed burner, the following method steps are also included:

[0021] By adopting fuel classification, a part of ammonia is mixed with the coal powder airflow and then sprayed into the coal powder airflow channel from the contraction section, and then passes through the second steady flow section, the expansion section, and the first steady flow section in sequence, and is separated into two swirls of thick and thin, so that the ammonia and coal powder are fully mixed; the high-temperature flue gas in the furnace is sucked in, so that the coal powder ignites and burns; then, the concentration of H and OH free radicals in the environment is increased by spraying water into the furnace; then, the remaining ammonia is sprayed into the furnace from the ammonia channel; the expansion angle of the guide plate is adjusted to prevent the ammonia from combining with the secondary air too early in the early stage of combustion and being oxidized into NO x ; Finally, the secondary air is sprayed into the furnace through the secondary air channel to achieve complete combustion of coal powder and ammonia.

[0022] The advantages and positive effects of the present invention are:

[0023] The invention discloses a swirl burner for ammonia-coal co-combustion, wherein a bluff body is arranged in a first cylinder, wherein the front end of the bluff body is a cylinder and the rear end is a truncated cone; except for a part of the rear end of the bluff body located inside and outside the gradual expansion section, the rest of the bluff body is located in the first steady flow section; when the pulverized coal airflow passes through the channel and the bluff body, it is separated into two airflows, one thick and one thin, wherein the outer diameter is the thick side pulverized coal flow and the inner diameter is the thin side pulverized coal flow. The pulverized coal airflow passes through the swirl blades to form a swirl, thereby enhancing thermal disturbance and strengthening the combustion of pulverized coal.

[0024] The outer edge of the front end of the bluff body is provided with grooves evenly distributed along the circumference, and multiple grooves form a flame stabilizing ring. This design increases the folds of the coal powder flame surface and strengthens the coal powder combustion.

[0025] The water spray device provides H and OH free radicals to the environment, promotes the dehydrogenation reaction of ammonia, and reduces the NO generated during the co-combustion process. x .

[0026] The guide plate can flexibly adjust the expansion angle to prevent ammonia from combining with the secondary air too early and oxidizing to produce NO x .

[0027] During the pulverized coal combustion process, the outer concentrated pulverized coal flow will consume a large amount of O2 to form an oxygen-deficient atmosphere. At this time, it will combine with the ammonia at the outlet of the ammonia channel to help the ammonia reduce the NO generated by combustion in the oxygen-deficient atmosphere. x The ammonia-coal mixed swirl burner mainly plays a transitional role in allowing coal-fired boilers to burn from pure coal to high-proportion ammonia-mixed combustion, which is of great significance for the green and low-carbon transformation of future coal-fired power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 An axial cross-sectional view of a swirl burner for ammonia-coal co-firing according to the present invention

[0029] Figure 2 It is a schematic diagram of the three-dimensional structure of a swirl burner for ammonia-coal co-firing according to the present invention.

[0030] Figure 3 It is a front view of a swirl burner for ammonia-coal co-firing according to the present invention.

[0031] In the figure, 1, first cylinder; 2, second cylinder; 3, third cylinder; 4, second steady flow section; 5, first steady flow section; 6, ammonia channel; 7, secondary air channel; 8, guide plate; 9, groove; 10, front end of blunt body; 11, swirl blade; 12, rear end of blunt body; 13, gradually expanding section; 14, gradually contracting section; 15, through hole. DETAILED DESCRIPTION

[0032] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0033] In the description of the present invention, the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention rather than requiring the present invention to be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention. The terms "connected" and "connection" used in the present invention should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be a direct connection or an indirect connection through an intermediate component; it can also be an electrical connection or signal transmission; for those of ordinary skill in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0034] See also Figures 1 to 3 A swirl burner for ammonia-coal mixed combustion comprises a first cylinder 1, a second cylinder 2, and a third cylinder 3 which are sleeved in sequence from the inside to the outside; the inner cavity of the first cylinder 1 forms a coal powder airflow channel; the cavity between the first cylinder 1 and the second cylinder 2 forms an ammonia channel 6; the cavity between the second cylinder 2 and the third cylinder 3 forms a secondary air channel 7; the inner cavity of the first cylinder 1 is divided into four sections from front to back, which are a first steady flow section 5, a gradually expanding section 13, a second steady flow section 4, and a gradually contracting section 14, the first steady flow section 5 and the second steady flow section 4 are cylindrical, the gradually expanding section 13 and the gradually contracting section 14 are cylindrical, and the gradually expanding section 13 and the gradually contracting section 14 are cylindrical. The section 14 is in the shape of a truncated cone, the front end diameter of the gradually expanding section 13 is larger than the rear end diameter; the front end diameter of the gradually contracting section 14 is smaller than the rear end diameter; a blunt body is arranged in the first cylinder 1, the front end of the blunt body is a cylinder and the rear end is a truncated cone; except for a part of the rear end of the blunt body located inside and outside the gradually expanding section 13, the rest of the blunt body is located in the first steady flow section 5; a swirl blade 11 is connected between the inner wall of the first cylinder 1 and the outer wall of the blunt body; a plurality of guide plates 8 with adjustable outward opening angles are evenly distributed along the circumferential direction at the front end of the second cylinder 2; the outward opening angle adjustment range of the guide plates 8 is 0 to 30 degrees. Multiple guide plates 8 are surrounded to form a trumpet shape.

[0035] The guide plate 8 can be hinged to the front end of the second cylinder 2 via a rotating shaft, so that the outward opening angle can be adjusted. The rotating shaft is connected to the guide plate 8, and the guide plate 8 rotates with the rotating shaft.

[0036] Various transmission and drive structures in the prior art can be used to drive the rotating shaft to rotate. For example, a motor is set at the rear end of the swirl burner, and the motor output shaft is connected to the rotating shaft through a chain transmission structure. The chain is driven by the forward and reverse rotation of the motor, and the chain drives the rotating shaft forward and reverse. The outward opening angle of the guide plate 8 can be controlled by controlling the rotation angle of the motor.

[0037] A swing rod or a pendulum wheel can also be set at one or both ends of the rotating shaft, and the swing rod or the pendulum wheel is vertically connected to the rotating shaft, and the swing of the swing rod or the pendulum wheel drives the rotating shaft to rotate; for example, a motor is set at the rear end of the swirl burner, and the motor drives the fan wheel; the fan wheel can be the same shape as the pendulum wheel; one end of the two pull ropes is connected to the two end points of the circumference of the fan wheel; the other ends of the two pull ropes are connected to the two end points of the circumference of the pendulum wheel or the two ends of the swing rod; the motor output shaft is connected to the fan wheel, and the fan wheel is driven to swing by the motor's forward and reverse rotation, and the pendulum wheel or the swing rod is driven to swing by the pull rope, thereby driving the rotating shaft forward and reverse. The outward opening angle of the guide plate 8 can be controlled by controlling the rotation angle of the motor.

[0038] Preferably, the front end surface of the third cylinder 3 is 3 to 7 mm longer than the front end surface of the second cylinder 2 in the axial direction.

[0039] Preferably, the outer edge of the front end 10 of the bluff body may be provided with grooves 9 uniformly distributed along the circumferential direction, and the plurality of grooves 9 form a flame stabilizing ring.

[0040] Preferably, a plurality of axial through holes 15 may be evenly distributed along the circumferential direction in the wall of the first cylinder 1; the rear ends of the through holes 15 are connected to the water supply device. The plurality of axial through holes 15 and the water supply device constitute a water spray device.

[0041] Preferably, the length of the first cylinder 1 can be 80-100 mm, the inner diameter of the first steady flow section 5 can be 26-35 mm, and the length can be 40-50 mm; the inner diameter of the second steady flow section 4 can be 15-24 mm; the length can be 40-50 mm; the length of the gradually expanding section 13 can be 15-18 mm; the length of the gradually contracting section 14 can be 10-12 mm.

[0042] Preferably, the maximum diameter of the truncated cone in the bluff body can be 14-18 mm, and the minimum diameter can be 6-10 mm. The length of the cylindrical part of the bluff body can be 20-25 mm, and the length of the truncated cone part of the bluff body can be 12-16 mm.

[0043] Preferably, the gap between the first cylinder 1 and the second cylinder 2 may be 0.6-1 mm; the gap between the second cylinder 2 and the third cylinder 3 may be 0.8-1.2 mm.

[0044] Preferably, the guide plate 8 may have a length of 4 to 6 mm along the axial direction of the swirl burner, and a thickness of 0.5 to 0.8 mm.

[0045] The above-mentioned structural lengths all refer to the lengths in the axial direction.

[0046] The present invention also provides several methods for using the above-mentioned swirl burner for ammonia-coal mixed combustion, and uses the swirl burner as a pure coal burner and / or an ammonia-coal mixed burner;

[0047] When the swirl burner is used as a pure coal burner, the method comprises the following steps:

[0048] The pulverized coal mixed primary air is sprayed into the pulverized coal airflow channel from the converging section 14, and sequentially passes through the second steady flow section 4, the expanding section 13, and the first steady flow section 5, and is separated into two swirls of thick and thin, which suck in the high-temperature flue gas in the furnace, so that the pulverized coal ignites and burns; then, the remaining air is divided into internal and external secondary air, and the internal secondary air is first sprayed into the furnace through the ammonia channel 6; the internal secondary air contacts and burns with the concentrated pulverized coal airflow at the outlet of the pulverized coal airflow channel; then, the expansion angle of the guide plate 8 is adjusted to increase the size of the central recirculation zone, so that the primary air pulverized coal flow is heated; finally, the external secondary air is sprayed into the furnace through the secondary air channel 7 to achieve complete combustion of the pulverized coal;

[0049] When the swirl burner is used as an ammonia-coal mixed burner, the method comprises the following steps:

[0050] The pulverized coal mixed with the primary air is injected from the coal pulverized air flow channel through the converging section 14, and sequentially passes through the second steady flow section 4, the expanding section 13, and the first steady flow section 5, and is separated into two swirls of thick and thin, which suck in the high-temperature flue gas in the furnace, so that the pulverized coal ignites and burns; subsequently, water is sprayed into the furnace to increase the concentration of H and OH free radicals in the environment; then, all the ammonia is directly injected into the furnace from the ammonia channel 6 at one time; the expansion angle of the guide plate 8 is adjusted to prevent the ammonia from combining with the secondary air too early in the early stage of combustion and being oxidized into NO x Finally, the secondary air is sprayed into the furnace through the secondary air channel 7 to achieve complete combustion of coal powder and ammonia.

[0051] Preferably, when the swirl burner is used as an ammonia-coal mixed burner, the following method steps may also be included:

[0052] By adopting fuel classification, a part of ammonia is mixed with the coal powder airflow and then sprayed into the coal powder airflow channel from the converging section 14, and is separated into two swirls of thick and thin after passing through the second steady flow section 4, the gradually expanding section 13, and the first steady flow section 5 in sequence, so that the ammonia and the coal powder are fully mixed; the high-temperature flue gas in the furnace is sucked in, so that the coal powder is ignited and burned; then, the concentration of H and OH free radicals in the environment is increased by spraying water into the furnace; then, the remaining ammonia is sprayed into the furnace from the ammonia channel 6; the expansion angle of the guide plate 8 is adjusted to prevent the ammonia from combining with the secondary air too early in the early stage of combustion and being oxidized into NO x Finally, the secondary air is sprayed into the furnace through the secondary air channel 7 to achieve complete combustion of coal powder and ammonia.

[0053] High-temperature flue gas refers to flue gas with a high temperature when it is discharged, usually above 800 degrees Celsius, and some high-temperature flue gas can even reach 1000 degrees Celsius. Low-temperature flue gas refers to flue gas with a low temperature when it is discharged, generally between 200 degrees Celsius and 400 degrees Celsius.

[0054] A separate water spraying device may be used to spray water into the furnace, such as a ring-shaped nozzle connected to a water supply pipeline to form a water spraying device, or a plurality of axial through holes 15 may be evenly distributed along the circumferential direction in the wall of the first cylinder 1; the rear end of the through hole 15 is connected to the water supply device. The plurality of axial through holes 15 and the water supply device constitute a water spraying device.

[0055] The structure, working process and working principle of the present invention are further described below with reference to a preferred embodiment of the present invention:

[0056] A swirl burner for ammonia-coal co-firing, comprising first to third cylinders 3 which are sequentially sleeved from the inside to the outside; the inner cavity of the first cylinder 1 forms a coal powder airflow channel; the cavity between the first and second cylinders forms an ammonia channel 6; the cavity between the second and third cylinders forms a secondary air channel 7; the inner cavity of the first cylinder 1 is divided into four sections, which are, from front to back, a first steady flow section 5, a gradually expanding section 13, a second steady flow section 4 and a gradually contracting section 14, the first and second steady flow sections are cylindrical, the gradually expanding section 13 and the gradually contracting section 14 are truncated cone-shaped, the front end diameter of the gradually expanding section 13 is larger than the rear end diameter; the front end diameter of the gradually contracting section 14 is smaller than the rear end diameter; that is, the inner cavity diameter of the first steady flow section 5 is larger than the inner cavity diameter of the second steady flow section 4.

[0057] A blunt body is arranged in the first cylinder 1, the front end 10 of the blunt body is a cylinder and the rear end 12 of the blunt body is a truncated cone; except for a part of the rear end of the blunt body located inside and outside the gradually expanding section 13, the rest of the blunt body is located in the first steady flow section 5; a swirl blade 11 is connected between the inner wall of the first cylinder 1 and the outer wall of the blunt body; a plurality of guide plates 8 with adjustable outward opening angles are evenly distributed along the circumferential direction at the front end of the second cylinder 2; the outward opening angle of the guide plates 8 is adjustable in the range of 0 to 30 degrees. A plurality of guide plates 8 are enclosed in a trumpet shape. That is, the inner cavity diameter of the first steady flow section 5 is greater than the inner cavity diameter of the second steady flow section 4.

[0058] The pulverized coal airflow cylindrical channel includes a first steady flow section 5, a gradually expanding section 13, a second steady flow section 4, and a gradually contracting section 14, which are used for conveying the pulverized coal airflow and separating the dense and thin pulverized coal airflow. The function of the gradually contracting section 14 is to converge the pulverized coal flow, the function of the steady flow section is to stabilize the airflow, and the function of the gradually expanding section 13 is to enhance the radial diffusion of the pulverized coal flow.

[0059] The front end 10 of the bluff body is a cylinder, and the rear end 12 of the bluff body is a truncated cone. The front end 10 of the bluff body is used for stabilizing the flow, and the rear end 12 of the bluff body is used for enhancing the radial diffusion of the coal powder flow.

[0060] The outer edge of the front end 10 of the bluff body is provided with a plurality of grooves 9 evenly distributed along the circumferential direction, and the plurality of grooves 9 form a flame stabilizing ring for strengthening combustion;

[0061] Swirl blades 11 are provided on the circumference of the bluff body to enhance the radial diffusion of the pulverized coal flow and to form a swirl to enhance thermal disturbance and strengthen the combustion of the pulverized coal.

[0062] The inner cavity of the first cylinder 1 has a length of 90 mm, a minimum diameter of 20 mm and a maximum diameter of 30 mm.

[0063] The maximum diameter of the blunt body is 16 mm, and the minimum diameter is 8 mm. The length of the cylindrical part of the blunt body can be 20 to 25 mm, and the length of the truncated cone part of the blunt body can be 12 to 16 mm.

[0064] The second cylinder 2 has a length of 90 mm and a wall thickness of 0.8 mm.

[0065] The third cylinder 3 has a length of 95 mm and a wall thickness of 1 mm.

[0066] The gap between the first and second cylinders is 0.8 mm; the gap between the second and third cylinders is 1 mm.

[0067] Twenty axial through holes 15 are evenly distributed in the circumferential direction in the wall of the first cylinder 1; the rear ends of the through holes 15 are connected to the water supply device. The diameter of the through holes 15 is 0.6 mm.

[0068] The guide plate 8 has a length of 4 mm and a thickness of 0.6 mm along the axial direction of the swirl burner.

[0069] The pulverized coal airflow channel adopts a design similar to that of a venturi tube. When the pulverized coal airflow passes through the channel and the blunt body, it is separated into two streams, dense and thin. The outer diameter is the dense side pulverized coal flow, and the inner diameter is the thin side pulverized coal flow. The pulverized coal airflow passes through the swirl blades 11 to form a swirl, which enhances thermal disturbance and strengthens the combustion of pulverized coal. The flame stabilizing ring increases the wrinkles on the flame surface of the pulverized coal and strengthens the combustion of pulverized coal. During the combustion of pulverized coal, the combustion of the dense pulverized coal flow on the outside consumes a large amount of O2, forming an oxygen-deficient atmosphere. At this time, it combines with the ammonia at the outlet of the ammonia channel 6, which helps the ammonia to reduce the NO generated by combustion in the oxygen-deficient atmosphere. x The guide plate 8 can flexibly adjust the expansion angle to prevent ammonia from combining with the secondary air too early and being oxidized to produce NO. x The water supply system sprays water into the furnace through the axial through hole 15 in the wall of the first cylinder 1 to provide H and OH free radicals for the environment.

[0070] The swirl burner can be used as a pure coal burner and / or an ammonia-coal mixed burner.

[0071] When the swirl burner is used as a pure coal burner, the method comprises the following steps:

[0072] The pulverized coal mixed with primary air is injected from the pulverized coal airflow channel's converging section 14, and sequentially passes through the steady flow section, the expanding section 13, the bluff body's rear end 12, and the bluff body's front end 10, and is separated into two swirls of thick and thin air, which suck in the high-temperature flue gas in the furnace, causing the pulverized coal to ignite and burn; subsequently, the remaining air is divided into inner and outer secondary air, and the inner secondary air is first injected into the furnace through the ammonia channel 6; the inner secondary air contacts and burns with the thick pulverized coal airflow at the outlet of the pulverized coal airflow channel, consuming oxygen and suppressing the formation of fuel-type NO in the initial stage of pulverized coal combustion. x Then, the expansion angle of the guide plate 8 is adjusted to increase the size of the central recirculation zone, and a large amount of high-temperature flue gas flows back to the burner outlet, so that the turbulent pulsation level of the outlet airflow is improved, the heat and mass exchange between the airflows is strengthened, and the primary air pulverized coal flow is heated up, which is very beneficial to the ignition and stable combustion of the pulverized coal; finally, the external secondary air is sprayed into the furnace through the secondary air channel 7 to promote the mixing of the unburned materials remaining in the reduction zone with the air, so as to achieve complete combustion of the pulverized coal;

[0073] When the swirl burner is used as an ammonia-coal mixed burner, the method comprises the following steps:

[0074] No fuel grading is adopted; the pulverized coal mixed with primary air is sprayed into the pulverized coal airflow channel from the converging section 14, and passes through the steady flow section, the expanding section 13, the rear end 12 of the blunt body, and the front end 10 of the blunt body in sequence, and is separated into two swirls of thick and thin, which suck in the high-temperature flue gas in the furnace, so that the pulverized coal quickly ignites and burns; at this time, the flame stabilizing ring is conducive to improving the stability of the pulverized coal flame; then, the water supply system is used to spray water into the furnace through the axial through hole 15 in the wall of the first cylinder 1 to increase the concentration of H and OH free radicals in the environment; then, all the ammonia is directly sprayed into the furnace from the ammonia channel 6 at one time; since the combustion of the concentrated pulverized coal airflow at the outer diameter of the pulverized coal airflow channel outlet consumes a large amount of oxygen to form an oxygen-deficient area, the addition of ammonia is helpful to reduce the fuel-type NO in the early stage of combustion. x ; Adjust the expansion angle of the guide plate 8 to prevent ammonia from combining with the secondary air too early in the early stage of combustion and being oxidized into NO x ; Finally, the secondary air is sprayed into the furnace through the secondary air channel 7 to promote the mixing of the unburned materials remaining in the reduction zone with the air, so as to achieve complete combustion of the pulverized coal and ammonia;

[0075] By adopting fuel grading, a part of ammonia is mixed with the coal powder airflow and then sprayed into the coal powder airflow channel from the converging section 14, and is separated into two swirls of thick and thin after passing through the steady flow section, the expanding section 13, the blunt body rear end 12, and the blunt body front end 10 in sequence, so that the ammonia and coal powder are mixed more fully; since the ignition of ammonia is earlier than that of coal powder, the combustion of ammonia helps to release the volatile matter of coal powder and promote the subsequent ignition of coal powder; at this time, the flame stabilizing ring is conducive to improving the stability of the flame; then, the water supply system is made to spray water into the furnace through the axial through hole 15 in the wall of the first cylinder 1 to increase the concentration of H and OH free radicals in the environment; then, the remaining ammonia is sprayed into the furnace from the ammonia channel 6; ammonia is used to reduce NO in an oxygen-deficient environment x ; Adjust the expansion angle of the guide plate 8 to prevent ammonia from combining with the secondary air too early in the early stage of combustion and being oxidized into NO x Finally, the secondary air is sprayed into the furnace through the secondary air channel 7 to promote the mixing of the unburned materials remaining in the reduction zone with the air, thereby achieving complete combustion of the pulverized coal and ammonia.

[0076] The first to third cylinders, the bluff body, the annular nozzle, the water supply pipeline, the water spray device, the guide plate, etc. can all adopt applicable parts and structures in the prior art, or adopt parts in the prior art and construct by conventional technical means.

[0077] The embodiments described above are only used to illustrate the technical ideas and features of the present invention, and their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. The patent scope of the present invention cannot be limited only by this embodiment, that is, any equivalent changes or modifications made to the spirit disclosed by the present invention still fall within the patent scope of the present invention.

Claims

1. A swirl burner for ammonia-coal co-firing, characterized in that: The invention comprises the first to third cylinders which are sleeved in sequence from the inside to the outside; the inner cavity of the first cylinder forms a coal powder airflow channel; the cavity between the first and second cylinders forms an ammonia channel; the cavity between the second and third cylinders forms a secondary air channel; the inner cavity of the first cylinder is divided into four sections from front to back, which are the first steady flow section, the gradually expanding section, the second steady flow section and the gradually contracting section in sequence; the first and second steady flow sections are cylindrical, the gradually expanding section and the gradually contracting section are truncated cone-shaped, the front end diameter of the gradually expanding section is larger than the rear end diameter; the front end diameter of the gradually contracting section is smaller than the rear end diameter; a blunt body is arranged in the first cylinder, the front end of the blunt body is a cylinder and the rear end is a truncated cone; except for a part of the rear end of the blunt body which is located inside and outside the gradually expanding section, the rest of the blunt body is located in the first steady flow section; a swirl blade is connected between the inner wall of the first cylinder and the outer wall of the blunt body; a plurality of guide plates with adjustable outward opening angles are evenly distributed along the circumferential direction at the front end of the second cylinder; the outward opening angle adjustment range of the guide plates is 0-30 degrees, and the plurality of guide plates are surrounded to form a trumpet shape.

2. The swirl burner for ammonia-coal co-firing according to claim 1, characterized in that: The front end surface of the third cylinder is 3 to 7 mm longer in the axial direction than the front end surface of the second cylinder.

3. The swirl burner for ammonia-coal co-firing according to claim 1, characterized in that: The outer edge of the front end surface of the bluff body is provided with grooves evenly distributed along the circumferential direction, and the plurality of grooves form a flame stabilizing ring.

4. The swirl burner for ammonia-coal co-firing according to claim 1, characterized in that: A plurality of axial through holes are evenly distributed in the circumferential direction in the wall of the first cylinder; rear ends of the through holes are communicated with the water supply device.

5. The swirl burner for ammonia-coal co-firing according to claim 1, characterized in that: The length of the first cylinder is 80-100mm, the inner diameter of the first steady flow section is 26-35mm, and the length is 40-50mm; the inner diameter of the second steady flow section is 15-24mm, and the length is 40-50mm; the length of the gradually expanding section is 15-18mm; and the length of the gradually contracting section is 10-12mm.

6. The swirl burner for ammonia-coal co-firing according to claim 1, characterized in that: The maximum diameter of the cone in the blunt body is 14-18 mm, and the minimum diameter is 6-10 mm; the length of the cylindrical part of the blunt body is 20-25 mm, and the length of the cone part of the blunt body is 12-16 mm.

7. The swirl burner for ammonia-coal co-firing according to claim 1, characterized in that: The gap between the first and second cylinders is 0.6-1 mm; the gap between the second and third cylinders is 0.8-1.2 mm.

8. The swirl burner for ammonia-coal co-firing according to claim 1, characterized in that: The guide plate has a length of 4 to 6 mm along the axial direction of the swirl burner and a thickness of 0.5 to 0.8 mm.

9. A method for using the swirl burner for ammonia-coal co-firing according to any one of claims 1 to 8, characterized in that: The swirl burner is used as a pure coal burner and / or an ammonia-coal mixed burner; When the swirl burner is used as a pure coal burner, the method comprises the following steps: The pulverized coal mixed primary air is sprayed into the pulverized coal airflow channel from the gradually contracting section, and passes through the second steady flow section, the gradually expanding section, and the first steady flow section in sequence, and is separated into two swirls of thick and thin, which suck in the high-temperature flue gas in the furnace, causing the pulverized coal to ignite and burn; then, the remaining air is divided into internal and external secondary air, and the internal secondary air is first sprayed into the furnace through the ammonia channel; the internal secondary air contacts and burns with the concentrated pulverized coal airflow at the outlet of the pulverized coal airflow channel; then, the expansion angle of the guide plate is adjusted to increase the size of the central recirculation zone, so that the primary air pulverized coal flow is heated; finally, the external secondary air is sprayed into the furnace through the secondary air channel to achieve complete combustion of the pulverized coal; When the swirl burner is used as an ammonia-coal mixed burner, the method comprises the following steps: The pulverized coal mixed with primary air is injected from the gradually contracting section of the pulverized coal airflow channel, and passes through the second steady flow section, the gradually expanding section, and the first steady flow section in sequence, and is separated into two swirls of thick and thin, which suck in the high-temperature flue gas in the furnace, causing the pulverized coal to ignite and burn; subsequently, water is sprayed into the furnace to increase the concentration of H and OH free radicals in the environment; then, all the ammonia is directly injected into the furnace from the ammonia channel at one time; the expansion angle of the guide plate is adjusted to prevent the ammonia from combining with the secondary air too early in the early stage of combustion and being oxidized into NO x ; Finally, the secondary air is sprayed into the furnace through the secondary air channel to achieve complete combustion of coal powder and ammonia.

10. The method for using the swirl burner for ammonia-coal co-firing according to claim 9, characterized in that: When the swirl burner is used as an ammonia-coal mixed burner, the method further comprises the following steps: By adopting fuel classification, a part of ammonia is mixed with the coal powder airflow and then sprayed into the coal powder airflow channel from the contraction section, and then passes through the second steady flow section, the expansion section, and the first steady flow section in sequence, and is separated into two swirls of thick and thin, so that the ammonia and coal powder are fully mixed; the high-temperature flue gas in the furnace is sucked in, so that the coal powder ignites and burns; then, the concentration of H and OH free radicals in the environment is increased by spraying water into the furnace; then, the remaining ammonia is sprayed into the furnace from the ammonia channel; the expansion angle of the guide plate is adjusted to prevent the ammonia from combining with the secondary air too early in the early stage of combustion and being oxidized into NO x ; Finally, the secondary air is sprayed into the furnace through the secondary air channel to achieve complete combustion of coal powder and ammonia.

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