CN111536511A - A pulverized coal swirl burner - Google Patents

Abstract

The invention discloses a pulverized coal swirl burner, comprising: a primary air channel, an inner secondary air channel and an outer secondary air channel arranged in sequence from the inside to the outside along the radial direction, the air outlet of the primary air channel is provided with a nozzle, Also includes air regulator. The air regulator includes outer secondary air sleeve baffle and outer secondary air sleeve baffle adjustment part, outer secondary air swirl blade and outer secondary air swirl blade adjustment part; outer secondary air sleeve baffle The adjusting part can drive the outer secondary air sleeve baffle plate to move to adjust the opening of the air inlet of the outer secondary air passage. The outer secondary air swirl blade adjusting part can drive the outer secondary air swirl blade to move. The pulverized coal swirl burner of the present application has no central air design, and a larger reducing area is formed at the burner nozzle. The pulverized coal entering the furnace can quickly ignite and heat up quickly, and can be released into the coal within a limited time. More CH groups are used to reduce the NOx generated in the main combustion zone of the burner to achieve reduction in the flame and reduce NOx.

Description

A pulverized coal swirl burner

technical field

The invention relates to the technical field of pulverized coal combustion, in particular to a pulverized coal swirl burner.

Background technique

The swirl burner is a device for burning pulverized coal widely used in power plant boilers and industrial boilers. With the continuous improvement of environmental protection requirements and the progress of ultra-low emission transformation in recent years, the application of low-nitrogen burners, as the most economical means of reducing nitrogen oxides, has become an inevitable choice for denitrification. Air staged combustion and excessive pursuit of lower NOx emissions at the furnace outlet have brought a series of problems to the operation of the boiler.

At present, the central air duct of the burner on the market is placed in the primary pulverized coal air flow, which is easy to wear and replace frequently, which increases the operation and maintenance cost and reduces the reliability of the system operation. The combustion system matched with this burner uses a large amount of over-burning air. Usually, the over-burning air accounts for more than 25% of the total air supply volume. The amount of desuperheating water in the boiler increases or even fully opens, and the economy of the boiler becomes poor; the central air needs to pass a small amount of cooling air during the operation of the boiler. The existence of this part of the air is easy to form an oxidizing atmosphere in the nozzle area of the burner, reducing the NOx during the combustion process. Lowering; the burner delays the mixing of primary air/secondary air by means of expanding cone, and controls the formation of NOx in combustion by means of delaying combustion, the ability to reduce NOx is weak, and the excessive cone expansion angle is rolled up The smoke from the seat is easy to burn and damage the nozzle and expanding cone.

In addition, with the increasingly wide range of coal-fired sources in power plants, the coal quality is becoming more and more unstable, and coal-fired units are more and more frequently participating in deep peak regulation, which brings new adjustments to the operation of the burner system. The swirl pulverized coal burner needs to be further improved at the comprehensive level.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the present invention provides a pulverized coal swirl burner.

According to one aspect of the present application, a pulverized coal swirl burner is provided, comprising: a primary air passage, an inner secondary air passage and an outer secondary air passage arranged in order from the inside to the outside in the radial direction, and an outlet of the primary air passage is The tuyere is provided with a nozzle, the pulverized coal swirl burner is an equal flow burner, and also includes an air regulator for controlling and adjusting the secondary air; the air regulator includes an outer secondary air sleeve baffle and an outer secondary air jacket The barrel baffle adjustment part, the outer secondary air swirl blade and the outer secondary air swirl blade adjustment part; the outer secondary air sleeve baffle is sleeved at the air inlet of the outer secondary air passage, and the outer secondary air sleeve The baffle adjustment part can drive the outer secondary air sleeve baffle to move within a predetermined range in the axial direction to adjust the opening of the air inlet of the outer secondary air passage; the outer secondary air swirl blades are circumferentially arranged on the outer secondary air In the air passage, the outer secondary air swirl blade adjusting part can drive the outer secondary air swirl blade to move in the axial direction to adjust the position of the outer secondary air swirl blade in the outer secondary air passage.

Optionally, the air regulator further comprises an inner secondary air sleeve baffle and an inner secondary air sleeve baffle adjustment part sleeved at the air inlet of the inner secondary air passage); the inner secondary air sleeve baffle The plate adjusting part can drive the inner secondary air sleeve baffle plate to move in the axial direction to adjust the opening of the air inlet of the inner secondary air passage.

Optionally, the inner secondary air passage is provided with a plurality of inner swirl blades distributed in the circumferential direction of the inner secondary air passage.

Optionally, an outer secondary air equalizing cylinder is installed at the air inlet of the outer secondary air passage, and the outer secondary air equalizing cylinder is communicated with the outer secondary air passage and is densely covered with equalizing holes. The outer secondary air equalizing cylinder enters the outer secondary air duct circumferentially; the air inlet of the inner secondary air passage is equipped with an inner secondary air equalizing cylinder, and the inner secondary air equalizing cylinder is communicated with the inner secondary air passage and has a surface The distribution holes are densely distributed, and part of the outer secondary air in the outer secondary air duct enters the inner secondary air duct circumferentially through the inner secondary air equalizing cylinder.

Optionally, the baffle adjustment part of the outer secondary air sleeve includes a roller skating guide rail arranged along the axial direction of the burner, a roller skating device assembled in the roller skating guide rail, and a pull rod of the outer secondary air sleeve baffle plate connected with the roller skating device, The outer secondary air sleeve baffle is connected with the roller skating device, and the pull rod of the outer secondary air sleeve baffle can push the roller skating device to slide in the roller skating guide rail to adjust the position of the outer secondary air sleeve baffle.

Optionally, the nozzle includes a plurality of inner constricted parts and outer expanded parts arranged alternately in the circumferential direction, the inner constricted part and the outer expanded part extend along the flow direction of the primary air, and the inner constricted part is constricted along the radial direction of the nozzle, and the outer expanded part is along the flow direction of the primary air. Radial expansion of the nozzle.

Optionally, the indented portion of the nozzle extends from the nozzle of the nozzle to the inside of the primary air passage along the opposite direction of the primary air flow, and the extension length L of the indented portion is 0.5-1.5 of the diameter D of the primary air passage.

Optionally, the flow area at the outlet of the nozzle is the same as the flow area of the primary air channel.

Optionally, the flared portion is provided with combustion stabilizing teeth extending outward along the radial direction of the nozzle at the outlet of the nozzle.

Optionally, the air inlet of the first air passage is connected with the burner elbow to enter the air through the burner elbow, and a pulverized coal flow equalizing plate is arranged in the burner elbow.

The pulverized coal swirl burner of the present application has no central air design, and a larger reducing area is formed at the nozzle of the burner. The pulverized coal entering the furnace can quickly ignite and heat up quickly, and can be released into the coal within a limited time. More CH groups are used to reduce the NOx generated in the main combustion zone of the burner to achieve reduction in the flame and reduce NOx.

Description of drawings

The accompanying drawings constituting a part of the present invention are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the attached image:

FIG. 1 is a schematic structural diagram of the pulverized coal swirl burner of the present application.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. It should be noted that the embodiments in this application and the feature vectors in the embodiments may be arbitrarily combined with each other unless there is a conflict.

The common shortcomings of the existing burner structure design are as follows: the central air duct is placed in the primary coal pulverized air flow, which is easy to wear and is frequently replaced, which increases the operation and maintenance cost and reduces the reliability of the system operation. The central air needs to pass a small amount of cooling air when the boiler is running. The existence of this part of the air is easy to form an oxidizing atmosphere in the nozzle area of the burner, which reduces the reduction of NOx during the combustion process. The combustion stabilizing teeth are arranged on the inner wall of the primary air nozzle, and the formed center tempering is easy to burn the nozzle of the burner. At present, the burner of the boiler operation generally has the problem of nozzle burning. The burner uses the method of expanding cone to delay the mixing of primary air/air and secondary air, and controls the formation of NOx in combustion by delaying the combustion. The ability to reduce NOx is weak, and the excessive cone expansion angle is swept away. The flue gas is easy to burn and damage the nozzle and expanding cone. The combustion system supporting the burner uses a large amount of over-burning air. Usually, the over-burning air accounts for more than 25% of the total air supply, which is easy to cause excessive oxygen-deficient combustion in the furnace area, which is easy to cause high temperature corrosion and delayed combustion. The amount of desuperheating water in the boiler increases or even fully opens, and the economy of the boiler becomes poor. The total secondary air adjustment sleeve of the burner is arranged in the dusty environment of the boiler wind box. The adjustment device of the annular hinge structure often jams, which makes the burner The structure of the non-adjustable burner swirl intensity blade adjusts the angle through the hoop hinge structure, because it is arranged in the dusty environment of the boiler bellows, it is easy to jam and the burner cannot be adjusted.

To this end, the present application provides a pulverized coal swirl burner, comprising: a primary air channel 10, an inner secondary air channel 30 and an outer secondary air channel 20 arranged in order from the inside to the outside in the radial direction. The air outlet is provided with a nozzle 40, and the burner also includes a register 50 for controlling and regulating the secondary air. The pulverized coal swirl burner of the present application has no central air design, and a larger reducing area is formed at the nozzle of the burner. The rapid ignition and rapid temperature rise of the pulverized coal entering the furnace can release coal in a limited time. More CH groups are used to reduce the NOx generated in the main combustion zone of the burner to achieve reduction in the flame and reduce NOx.

As shown in FIG. 1 , the pulverized coal swirl burner of the present application includes: a primary air passage 10 , an inner secondary air passage 20 and an outer secondary air passage 30 arranged in order from the inside to the outside in the radial direction, and the primary air passage 10 The air outlet is provided with a nozzle 40, the pulverized coal swirl burner is a uniform flow burner, and the burner also includes an air regulator 50 for controlling and adjusting the secondary air. The register 50 includes an outer secondary air sleeve baffle 51 , an outer secondary air sleeve baffle adjustment portion 57 , an outer secondary air swirl blade 53 and an outer secondary air swirl blade adjustment portion 58 . Compared with the conventional burner, which controls the total intake air volume and swirl intensity by adjusting the blade angle, the present application realizes the independent control of the total secondary air volume and the outer secondary air swirl intensity.

The outer secondary air sleeve baffle 51 is sleeved at the air inlet of the outer secondary air channel 20 , and the outer secondary air sleeve baffle adjustment part 57 can drive the outer secondary air sleeve baffle 51 to pre-determine in the axial direction. It can be moved within the range to adjust the opening of the air inlet of the outer secondary air passage 20 to control the total secondary air volume entering the burner.

The outer secondary air swirl blades 53 are circumferentially disposed in the outer secondary air passage 20, and the outer secondary air swirl blade adjusting part 58 can drive the outer secondary air swirl blades 53 to adjust the position of the outer secondary air swirl blades 53. The position in the axial direction is to adjust the volume of the outer secondary air that is swirl-enhanced by the outer secondary air swirl blades 53 . The outer secondary air swirl blade adjusting part 58 moves the outer swirl blades 53 to the inside of the outer secondary air passage 20, and all the outer secondary air entering from the air inlet of the outer secondary air passage 20 passes through the outer secondary air swirl. The swirl of the flow blades 53 is enhanced, and the outer secondary air swirl blade adjustment part 58 moves the outer swirl blades 53 to the air inlet of the outer secondary air passage 20, and enters the outer secondary air from the air inlet of the outer secondary air passage 20. All the outer secondary air swirl blades 53 cannot pass through, thereby achieving the effect of adjusting the intensity of the outer secondary air swirl.

As an example, the outer secondary air passage 20 is provided with a plurality of outer swirl blades 53 distributed in the circumferential direction of the outer secondary air passage 20 , and the plurality of outer swirl blades 53 are arranged around the outer secondary air passage 20 The outer secondary air swirl blade adjusting part 58 is connected with the blade base to drive the blade base to integrally drive the outer swirl blades 53 to move in the outer secondary air passage 20 .

As an example, the air regulator 50 further includes an inner secondary air sleeve baffle 54 and an inner secondary air sleeve baffle adjustment portion 59 sleeved at the air inlet of the inner secondary air passage 30; The air sleeve baffle adjusting part 59 can drive the inner secondary air sleeve baffle 54 to move in the axial direction to adjust the opening of the air inlet of the inner secondary air passage 30 and then control the air intake into the inner secondary air passage 30 . Internal secondary air volume.

As an example, the inner secondary air channel 30 is provided with several inner swirl blades 56 distributed in the circumferential direction of the inner secondary air channel 30 .

Based on the above example, in a feasible implementation, the position of the inner swirl vanes 56 in the inner secondary air passage 30 is fixed, and all the inner secondary air entering the inner secondary air passage 30 is swirled by the inner swirl vanes 56 . flow enhancement.

As an example, as shown in FIG. 1 , the outer secondary air sleeve baffle adjustment part 57 includes a roller skating guide 571 arranged along the axial direction of the burner, a roller skating device 572 assembled in the roller skating guide 571 , and an outer secondary air sleeve The cylinder baffle pull rod 573, the outer secondary air sleeve baffle 51 is installed and connected to the roller skating device 572, and the outer secondary air sleeve baffle pull rod is connected to the roller skating device 572, which can push the roller skating device to slide in the roller skating guide rail 571 and then move the outer two The position of the secondary air sleeve baffle 51 .

Among them, the roller skating guide 571 can be set as a single-track track or a double-track track according to the needs of the device, the roller skating guide 571 is arranged on the top of the outer secondary air duct 20 in the axial direction, and the outer secondary air sleeve baffle 51 can be slid along the roller skating guide 571 Adjustment The opening degree of the air inlet of the outer secondary air duct 20, the method of adjusting the total secondary air volume entering the outer secondary air duct 20 of the present application is more suitable for the operating environment of the boiler with many ash air ducts, and the adjustment method is flexible and not easy to jam , to ensure long-term flexible adjustment.

Based on the above example, in a feasible implementation manner, the burner of the present application is arranged on the burner bracket, and the wheel guide rail 571 is connected to the burner bracket and suspended above the outer secondary air duct 20 of the burner.

Based on the above examples, both the outer secondary air swirl blade adjusting portion 58 and the inner secondary air sleeve baffle adjusting portion 59 can be designed as push rods.

Wherein, the air inlet of the outer secondary air passage 20 is installed with an outer secondary air equalizing cylinder 52, and the outer secondary air equalizing cylinder 52 communicates with the outer secondary air passage 20 and is densely covered with equalizing holes on the surface, and the secondary air passes through The outer secondary air equalizing cylinder 52 enters the outer secondary air duct 20 circumferentially and enters the outer secondary air duct 20 uniformly, and the outer secondary air and the primary air duct 10 are ejected from the air outlet of the outer secondary air duct 20 The pulverized coal in the primary air is burned evenly, which can effectively avoid the occurrence of partial burning of the burner flame.

Further, the air inlet of the inner secondary air passage 30 is installed with an inner secondary air flow equalizing sleeve 55, and the inner secondary air equalizing cylinder 55 is communicated with the inner secondary air passage 30 and is densely covered with equalizing holes on the surface. The secondary air enters the inner secondary air duct 30 circumferentially through the inner secondary air equalizing sleeve 55 and enters the inner secondary air duct 30 evenly in the circumferential direction, and the inner secondary air is ejected from the air outlet of the inner secondary air duct 30. The secondary air and the pulverized coal in the primary air ejected from the primary air channel 10 are burnt in a balanced manner, which can effectively avoid the occurrence of partial burning of the burner flame.

As an example, the nozzle 40 of the pulverized coal swirl burner of the present application includes several inner constricted parts 41 and outer expanded parts 42 arranged alternately in the circumferential direction, and the inner constricted parts 41 and the outer expanded parts 42 extend along the flow direction of the primary air , and the inwardly constricted portion 41 is contracted along the radial direction of the nozzle 40 , and the outwardly expanded portion 42 is outwardly expanded along the radial direction of the nozzle 40 . Under this condition, the outer expansion part 42 and the two adjacent inner constriction parts 41 form a cutting channel, and the primary air in the primary air channel 10 enters the nozzle 40 and is cut into several pulverized coal airflows through the cutting channel, thereby expanding the coal The contact area between the pulverized gas flow and the high-temperature flue gas in the furnace rapidly increases the temperature rise rate and temperature of the pulverized coal gas flow, strengthens the ignition efficiency of the pulverized coal gas flow, and helps the early precipitation of volatile matter in the pulverized coal. The gas burner has no central air passage, and multiple pulverized coal airflows can form a larger reducing area in the burner nozzle area, which controls the formation of NOx in the early stage of the burner.

Based on the above example, in a feasible implementation, the nozzle 40 includes 4 to 8 inwardly constricted portions 41 and outwardly expanded portions 42 , and the dimensions of the inwardly constricted portion 41 and the outwardly expanded portion 42 of the nozzle 40 are the same. After the primary air pulverized coal airflow in the primary air channel enters the nozzle, it is divided into 4 to 8 pulverized coal airflows.

Based on the above example, in a feasible implementation manner, the indented portion 41 of the nozzle 40 extends from the nozzle of the nozzle 40 to the inside of the primary air passage 10 in the opposite direction of the primary air flow, and the extension length L of the indented portion 41 is the primary air flow. The diameter D of the channel 10 is 0.5 to 1.5. Under this condition, the extension length of the inner constriction portion 41 is sufficient to cut the primary air entering the nozzle 40 into several strands, and the primary air from the nozzle 40 is evenly combusted with the inner secondary air and the outer secondary air to form a larger air at the nozzle. Restorative area.

Based on the above example, in a feasible implementation, the flow area at the outlet of the nozzle 40 is the same as the flow area of the primary air channel 10, and there is sufficient flow space in the primary air entering the nozzle 40, which helps to heat the pulverized coal and strengthens the combustion.

Based on the above example, in a feasible implementation, the flared portion 42 is provided with combustion stabilizing teeth 43 extending outward along the radial direction of the nozzle 40 at the outlet of the nozzle. The secondary air jetted from the inner secondary air channel 30 and the outer secondary air channel 20 flows to the combustion stabilizing teeth 43 and flows back to both sides of the combustion stabilizing teeth 43, which helps to heat the pulverized coal and intensifies the combustion. The combustion stabilizing teeth 43 of the burner of the present application extend outward along the radial direction of the nozzle. Compared with the conventional burner with the combustion stabilizing tooth structure disposed inside the nozzle, the nozzle is less likely to be burnt and the nozzle has a longer service life.

As an example, the air inlet of the first air passage 10 is connected to the burner elbow 60 for air intake, and the burner elbow 60 is provided with a pulverized coal equalizing plate 61 . The thickness of the pulverized coal in the primary air entering the first air channel 10 is uniform, and the pulverized coal in the primary air ejected from the primary air channel 10 can be burned evenly, so as to avoid the coal powder aggregation caused by the different weights of the air powder in the primary air. In 10, the burnout effect caused by the local concentration of pulverized coal is too rich, and the problem of excessive NOx production caused by the concentration of pulverized coal is too light and oxygen-enriched.

Based on the above example, in a feasible implementation, the burner elbow 60 is a right-angle elbow, and the burner elbow 60 includes an air-powder airflow inlet, an air-powder airflow outlet, and the pulverized coal disposed in the burner elbow 60 is a right-angle elbow. The flow plate 61, the pulverized coal flow plate 61 includes a first flow plate arranged in the horizontal section of the elbow and a second flow plate inclined at the vertical section of the elbow, and the first flow plate is horizontally arranged at the elbow On the center line of the horizontal section, the angle between the second equalizing plate and the first equalizing plate is 120-150°, and the pulverized coal airflow entering from the air-pulverized airflow inlet of the elbow of the burner passes through the pulverized coal equalizing plate 61 , the pulverized coal flow plate 61 blocks the pulverized coal in the airflow of the pulverized coal and gathers upward under the action of centrifugal force, so that the concentration of the pulverized coal in the primary air entering the first air passage 10 is uniform.

Wherein, in the application process, the structure of the burner elbow 60 is not limited to the structure shown in the embodiment, and any burner elbow structure that can separate the concentration of the pulverized coal can be selected according to the type of the pulverized coal.

As an example, the swirl burner of the present application is further provided with an outer secondary air expanding cone 42 at the air outlet of the outer secondary air passage 20 .

It should be noted that, herein, the terms "comprising", "comprising" or any other variation thereof are intended to encompass non-exclusive inclusion, such that an article or device comprising a list of elements includes not only those elements, but also no Other elements expressly listed, or those inherent to the article or equipment are also included. Without further limitation, an element defined by the phrase "comprising" does not preclude the presence of additional identical elements in the article or device comprising said element.

The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them, and the present invention is only described in detail with reference to the preferred embodiments. It should be understood by those of ordinary skill in the art that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and should be included in the scope of the claims of the present invention.

Claims (10)

1. A pulverized coal swirl burner, comprising: a primary air passage (10), an inner secondary air passage (30) and an outer secondary air passage (20) arranged in turn from the inside to the outside in the radial direction, the primary air passage (30) The air outlet of the air passage (10) is provided with a nozzle (40), characterized in that the pulverized coal swirl burner is an equalizing burner, and further comprises an air regulator (50) for controlling and adjusting the secondary air ; The air regulator (50) comprises an outer secondary air sleeve baffle plate (51), an outer secondary air sleeve baffle baffle adjustment part (57), an outer secondary air swirl blade (53) and an outer secondary air a swirl vane adjusting part (58); The outer secondary air sleeve baffle (51) is sleeved at the air inlet of the outer secondary air passage (20), and the outer secondary air sleeve baffle adjustment part (57) can drive the The outer secondary air sleeve baffle plate (51) moves within a predetermined range in the axial direction to adjust the opening of the air inlet of the outer secondary air passage (20); The outer secondary air swirl blade (53) is circumferentially arranged in the outer secondary air passage (20), and the outer secondary air swirl blade adjusting part (58) can drive the outer secondary air The swirl vanes (53) are moved in the axial direction to adjust the position of the outer secondary air swirl vanes (53) in the outer secondary air passage (20). 2 . The pulverized coal swirl burner according to claim 1 , wherein the air regulator ( 50 ) further comprises an inner two-piece sleeve sleeved at the air inlet of the inner secondary air passage ( 30 ). 3 . a secondary air sleeve baffle (54) and an inner secondary air sleeve baffle adjustment part (59); the inner secondary air sleeve baffle adjustment part (59) can drive the inner secondary air sleeve baffle The plate (54) moves in the axial direction to adjust the opening of the air inlet of the inner secondary air passage (30). 3 . The pulverized coal swirl burner according to claim 2 , wherein the inner secondary air channel ( 30 ) is provided with several circumferentially distributed around the inner secondary air channel ( 30 ). 4 . Internal swirl vanes (56). 4. The pulverized coal swirl burner according to claim 1, characterized in that, an outer secondary air equalizing cylinder (52) is installed at the air inlet of the outer secondary air passage (20), The secondary air equalizing cylinder (52) is communicated with the outer secondary air passage (20) and is densely covered with equalizing holes, and the gas outside the burner enters the outer secondary air equalizing cylinder (52) circumferentially. The above-mentioned secondary air duct (20); The air inlet of the inner secondary air passage (30) is provided with an inner secondary air equalizing cylinder (55), and the inner secondary air equalizing cylinder (55) is communicated with the inner secondary air passage (30). And the surface is densely covered with flow equalizing holes, and part of the outer secondary air in the outer secondary air duct (20) enters the inner secondary air duct (30) circumferentially through the inner secondary air equalizing cylinder (55). 5. The pulverized coal swirl burner according to claim 1, wherein the outer secondary air sleeve baffle adjustment part (57) comprises a wheel guide rail (571) arranged along the axial direction of the burner ), a roller skating device (572) assembled in the roller skating guide (571), and an outer secondary air sleeve baffle rod (573) connected with the roller skating device (572), the outer secondary air sleeve The baffle (51) is connected with the roller skating device (572), and the outer secondary air sleeve baffle pulling rod (573) can push the roller skating device (572) to slide in the roller skating guide rail (571) to adjust The position of the outer secondary air sleeve baffle (51). 6. The pulverized coal swirl burner according to claim 1, characterized in that the nozzle (40) comprises a plurality of inner constricted parts (41) and outer expanded parts (42) alternately arranged along the circumferential direction, the The inner constricted portion (41) and the outwardly expanded portion (42) extend along the flow direction of the primary air, and the inner constricted portion (41) is constricted along the radial direction of the nozzle (40), and the outwardly expanded portion (42) ) expands radially outward of the nozzle (40). 7. The pulverized coal swirl burner according to claim 6, wherein the indented portion (41) of the nozzle (40) extends from the nozzle of the nozzle (40) in the opposite direction of primary air flow To the inside of the primary air passage (10), the extension length L of the indented portion (41) is 0.5-1.5 of the diameter D of the primary air passage (10). 8. The pulverized coal swirl burner according to claim 7, characterized in that the flow area at the outlet of the nozzle (40) is the same as the flow area of the primary air passage (10). 9 . The pulverized coal swirl burner according to claim 8 , characterized in that, the outer expansion part ( 42 ) is provided with a radial direction of the nozzle ( 40 ) at the outlet of the nozzle ( 40 ). The combustion stabilizing teeth (43) extend outward in the direction. 10. The pulverized coal swirl burner according to claim 1, wherein the air inlet of the first air passage (10) is connected to the burner elbow (60) through the burner elbow (60) ) into the air, and a pulverized coal equalizing plate (61) is arranged in the elbow (60) of the burner.

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