A low-nitrogen emission combustor and a low-nitrogen combustion method of the combustor

Abstract

A low-nitrogen emission burner and a low-nitrogen combustion method of the burner. The low-nitrogen emission burner comprises a combustion cylinder seat, a mixing device and a fuel device. The combustion cylinder seat is provided with an air passage, and the air passage is provided with an air outlet at the front end of the combustion cylinder seat. The mixing device is arranged at the front end of the combustion cylinder seat, and the fuel device comprises a fuel main pipe and a plurality of fuel branch pipes which are annularly distributed on the outer periphery of the fuel main pipe. The low-nitrogen combustion method of the burner comprises using the burner. The low-oxygen air generated by the combustion of the main flame jetted out of the combustion head is discharged into the furnace from the front end of the first mixing cylinder, and the low-oxygen air in the furnace is sucked into the first mixing area behind the first mixing cylinder to form the furnace circulating cycle of the low-oxygen air. The secondary flame jetted out of the combustion head and the fuel branch pipes can be combusted by using the low-oxygen air in the furnace circulating cycle of the low-oxygen air, and the combustion produces low content of nitrogen oxides.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of burners, in particular to a low-nitrogen emission burner and a low-nitrogen combustion method of the burner. BACKGROUND

[0002] A burner produces NOx (nitrogen oxide) in the combustion process, which is an atmospheric pollutant. With the increasing environmental protection requirements for pollutants produced by combustion, reducing NOx has become a demand for burners. The production of nitrogen oxides can be reduced by flue gas recirculation. Flue gas recirculation is to open a hole after the boiler induced draft fan, and set a backflow fan to extract the flue gas produced by combustion, mix it with air, and then send it into the burner. The recirculated flue gas mixed with air dilutes the oxygen concentration on the one hand, and increases the amount of cold air without increasing the oxygen concentration on the other hand, thus helping to reduce the flame temperature and extend the combustion reaction time, thereby avoiding local high temperature in the furnace and effectively inhibiting the production of NOx. Flue gas recirculation requires modification of the boiler, and the flue gas will heat the burner, which requires additional heat insulation treatment of the burner. SUMMARY

[0003] The purpose of the present application is to overcome the above-mentioned shortcomings, and to provide a low-nitrogen emission burner and a low-nitrogen combustion method of the burner that can form an internal circulation.

[0004] To achieve the above-mentioned purpose, the technical solution of the present application is: a low-nitrogen emission burner, comprising a combustion cylinder seat, a mixing device, and a fuel device; the combustion cylinder seat is provided with an air passage, and the air passage is provided with an air outlet at the front end of the combustion cylinder seat;

[0005] The mixing device is arranged at the front end of the combustion cylinder seat, and the mixing device comprises a first mixing cylinder and a plurality of second mixing cylinders. The first mixing cylinder is arranged in front of the air outlet, and a first mixing area communicating with the outside is arranged between the rear end of the first mixing cylinder and the air outlet. The plurality of second mixing cylinders are annularly distributed around the first mixing cylinder;

[0006] The fuel device comprises a fuel main pipe and a plurality of fuel branch pipes annularly distributed around the fuel main pipe. The front end of the fuel main pipe is provided with a combustion head, and the combustion head is arranged at the position of the air outlet and faces the rear end of the first mixing cylinder. The front ends of the plurality of fuel branch pipes respectively face the rear ends of the plurality of second mixing cylinders.

[0007] The combustion cylinder seat comprises a combustion cylinder and a rear seat arranged at the rear end of the combustion cylinder, the combustion cylinder extends into the furnace, the front end of the combustion head and the fuel branch pipe sprays fuel to form a main flame. Air is introduced into the air passage, the air is blown from the air outlet to the first mixing cylinder, the main flame is limited to extend forward by the first mixing cylinder, under the joint action of the air flow blown forward from the air outlet, the rear outer periphery (first mixing area) of the main flame forms a low pressure area, the air in the furnace is sucked into the first mixing area from the side of the first mixing area to participate in the combustion of the main flame; the air in the furnace is low-oxygen air which has passed through the main flame combustion and is discharged from the front end of the first mixing cylinder, the low-oxygen air participating in the combustion of the main flame can reduce the generation of nitrogen oxides. The low-oxygen air generated by the combustion of the main flame is discharged from the front end of the first mixing cylinder into the furnace, and the low-oxygen air in the furnace is sucked into the first mixing area behind the first mixing cylinder, forming the in-furnace circulation of low-oxygen air.

[0008] The front end of the fuel branch pipe sprays fuel to the second mixing cylinder to form a secondary flame, when the first mixing area absorbs the low-oxygen air in the furnace from the side, it needs to pass through the front end of the combustion branch pipe arranged at the outer periphery of the first mixing area, the low-oxygen air in the furnace participates in the combustion of the secondary flame, which can reduce the generation of nitrogen oxides, and the second mixing cylinder forwards the low-oxygen air generated by the combustion of the secondary flame. When the distance between the first mixing cylinder and the front end of the combustion branch pipe is relatively close or negative, the suction force generated at the rear end of the second mixing cylinder can strengthen the overall suction force of the first mixing area and strengthen the in-furnace circulation. When the distance between the first mixing cylinder and the combustion branch pipe is enlarged, the suction force at the rear end of the second mixing cylinder cannot completely suck in all the low-oxygen air generated by the combustion of the secondary flame, part of the low-oxygen air generated by the combustion of the secondary flame will be sucked into the first mixing area to participate in the combustion of the main flame, which can further inhibit the generation of nitrogen oxides of the main flame.

[0009] Most of the combustion head, the fuel main pipe and the fuel branch pipe are in the air passage, the air in the air passage can cool the fuel main pipe and the fuel branch pipe, the high temperature in the furnace during the operation of the burner will not affect the fuel device, and the service life of the fuel device is improved.

[0010] Preferably, the fuel device is arranged in the air passage, the front end of the fuel branch pipe is exposed at the front end of the combustion cylinder seat, the air passage is provided with an air inlet at the rear end of the combustion cylinder seat, and the fuel device can be removed from the air inlet. The fuel device can be removed from the air passage, which is convenient for installation, maintenance and adjustment.

[0011] Preferably, the inner cylinder is movably arranged in the air passage, and the inner cylinder is sleeved on the outer side of the combustion head; the inner cylinder adjusting mechanism is arranged on the combustion cylinder seat and used for driving the inner cylinder to move; the inner cylinder adjusting mechanism comprises a push-pull rod, a bolt seat and an adjusting bolt; the bolt seat is arranged on the outer wall of the combustion cylinder seat; the adjusting bolt is in threaded connection with the bolt seat; one end of the push-pull rod is connected with the inner cylinder; the other end of the push-pull rod is hingedly connected with the adjusting bolt; and the inner cylinder is driven to move forward and backward by rotating the adjusting bolt. The inner cylinder can shield the outer periphery of the front end of the combustion head, so that the air flow of the air outlet changes the influence on the main flame sprayed by the combustion head, and the distance between the inner cylinder and the front end of the combustion head is adjusted to change the shape of the main flame. The front part of the main flame is limited in the range of the first mixing cylinder, so that the efficiency of the first mixing cylinder in previously conveying fuel is improved, and the suction of the first mixing area is changed.

[0012] Preferably, the fuel device further comprises a tail seat, a shunt valve core and an indicating bolt; the tail seat is internally provided with a fuel cavity; the rear ends of all the fuel branch pipes are in communication with the fuel cavity.

[0013] The shunt valve core is rotatably arranged on the tail seat; one end of the shunt valve core extends into the fuel cavity and is connected with the rear end of the fuel main pipe; the shunt valve core is provided, at the end extending into the fuel cavity, with a shunt port for simultaneously communicating the fuel main pipe and the fuel cavity; the tail seat is provided, near the shunt port, with a stop block; and the shunt valve core is rotated to change the shielding area of the stop block on the shunt port.

[0014] The other end of the shunt valve core is exposed on the outer wall of the tail seat to form an exposed end; an arc-shaped groove is arranged on the end face of the exposed end; and a scale is arranged on the end face of the exposed end and distributed along the arc-shaped groove; and the indicating bolt is in threaded connection with the tail seat after penetrating through the arc-shaped groove.

[0015] The fuel first enters the fuel cavity of the tail seat and is then shunted to the fuel main pipe and the fuel branch pipe; and the combustion device only needs to be connected with an air inlet pipe connected with the tail seat, so that the structure of the combustion device is simplified. The shunt valve core is used to control the amount of fuel in the fuel cavity flowing into the fuel main pipe, so that the fuel ratio of the front ends of the fuel main pipe and the fuel branch pipe is adjusted, the shape of the main flame and the secondary flame is changed, and a lower fuel shunt ratio of nitrogen oxide generation can be achieved by adjustment.

[0016] Preferably, the combustion cylinder seat is provided with an air inlet pipe; one end of the air inlet pipe extends into the air passage; the side of the tail seat is provided with a plug; the plug is sleeved with the air inlet pipe; the tail seat is provided, at the back position of the plug, with a jack; the jack is in threaded connection with the combustion cylinder seat; one end of the jack extends out of the side wall of the combustion cylinder seat to form an extended end; the jack is internally provided with a detection channel for communicating the fuel cavity; and the detection channel extends to the extended end. The jack is used to radially push against the tail seat to fix the fuel device in the air passage; and the extended end of the jack can be externally connected with a pressure gauge or a pressure sensor to monitor the pressure change in the fuel cavity.

[0017] Preferably, the front end of the combustion cylinder seat is provided with an outer taper surface which is tapered forward and centrally, the rear end of the second mixing cylinder is located at the lower middle part of the outer taper surface, and the front end of the fuel branch pipe is located at the rear end of the second mixing cylinder after passing through the outer taper surface; the front part of the air passage is provided with a compression section with a gradually reduced inner diameter, and the air outlet is located at the front end of the compression section. The outer taper surface can guide the low-oxygen air in the furnace to the second mixing cylinder, so that the low-oxygen air in the furnace is more easily guided to the rear of the second mixing cylinder. The compression section is used to compress the air in the air passage, so as to increase the flow rate of the air outlet, so that the first mixing area can generate sufficient suction around the periphery.

[0018] Preferably, the combustion head comprises a cup body, a nozzle seat, and at least three nozzles, the opening of the cup body faces forward, the front end of the nozzle seat extends into the cup body, all the nozzles are annularly and uniformly distributed at the front end of the nozzle seat, the outer end of the nozzle extends obliquely to the outer edge of the cup body, the cup body surrounds all the nozzles, and the rear end of the cup body is provided with a gas permeable hole. The air in the air passage can also blow the fuel sprayed by the nozzle forward through the gas permeable hole, so that the main flame extends forward.

[0019] Preferably, the front end of the second mixing cylinder extends from the front end of the first mixing cylinder, the rear end of the second mixing cylinder extends from the rear end of the first mixing cylinder, the inner diameter of the first mixing cylinder is greater than the inner diameter of the air outlet, and the inner diameter of the second mixing cylinder is greater than the inner diameter of the front end of the fuel branch pipe. The second mixing cylinder can transport the gas from the rear of the first mixing cylinder to the front of the first mixing cylinder, so that the furnace circulation of the low-oxygen air can be strengthened.

[0020] A low-nitrogen combustion method of a burner, comprising the following steps:

[0021] The combustion head at the front end of the fuel main pipe sprays fuel into the first mixing cylinder and burns to generate a main flame; the rear end of the first mixing cylinder is spaced apart from the combustion head by a first mixing area which is in communication with the outside;

[0022] The combustion head is arranged in the inner cylinder, the inner cylinder is arranged in the air passage, and the air passage blows air into the first mixing cylinder to assist the combustion of the main flame;

[0023] A plurality of fuel branch pipes distributed around the periphery of the fuel main pipe respectively spray fuel into a plurality of second mixing cylinders to generate a plurality of secondary flames, the rear end of the second mixing cylinder is spaced apart from the front end of the fuel branch pipe by a second mixing area, and the second mixing area is located at the periphery of the first mixing area;

[0024] Moving the front end of the inner cylinder to the front side of the combustion head adjusts the shape of the main flame, so that the first mixing area and the second mixing area form suction around the periphery.

[0025] Preferably, the above-mentioned burner is used to perform;

[0026] Further comprising the following steps:

[0027] The fuel main pipe and the fuel branch pipe are controlled by a distribution valve core to distribute fuel, the burner extends into the furnace to burn fuel, the nitrogen oxide content of the air in the furnace is monitored, the distribution valve core is adjusted to control the fuel distribution ratio of the fuel main pipe and the fuel branch pipe, when the nitrogen oxide content of the air in the furnace is detected to be at a low level, the adjustment of the distribution valve core is stopped, and the adjustment function of the distribution valve core is fixed.

[0028] By adopting the technical scheme, the beneficial effects of the present application are as follows: the low-oxygen air generated by the main flame combustion of the combustion head is discharged into the furnace from the front end of the first mixing cylinder, the low-oxygen air in the furnace is sucked into the first mixing area behind the first mixing cylinder to form the furnace circulating of low-oxygen air. The secondary flame of the combustion head and the fuel branch pipe can be combusted by the low-oxygen air in the furnace circulating of low-oxygen air, and the nitrogen oxide content generated by the combustion is low. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a structural schematic view of the present application;

[0030] Figure 2 is a structural schematic view of the internal structure of the present application;

[0031] Figure 3 is a structural schematic view of the fuel device of the present application;

[0032] Figure 4 is a structural schematic view of the front end of the present application.

[0033] MAIN REFERENCE NUMERALS:

[0034] Combustion cylinder seat 1; air passage 11; air outlet 12; air inlet 13; outer conical surface 14; compression section 15; mixing device 2; first mixing cylinder 21; second mixing cylinder 22; first mixing area 23; fuel device 3; fuel main pipe 31; fuel branch pipe 32; tail seat 33; fuel cavity 331; plug 332; stop block 333; combustion head 34; nozzle seat 341; cup body 342; nozzle 343; air permeable hole 344; distribution valve core 35; distribution port 351; arc-shaped groove 352; indicating bolt 36; inner cylinder 41; inner cylinder adjusting mechanism 42; top rod 5; detection passage 51; air inlet pipe 6. DETAILED DESCRIPTION

[0035] The present application will be further described below in combination with the drawings and specific embodiments.

[0036] As Figures 1-4As shown, this invention discloses a low-NOx burner, comprising a combustion chamber base 1, a mixing device 2, a fuel device 3, an inner cylinder 41, and an inner cylinder adjusting mechanism 42. The combustion chamber base 1 includes a combustion chamber and a rear seat located at the rear of the combustion chamber. An air passage 11 is provided within the combustion chamber base 1, with an outlet 12 at the front end and an inlet 13 at the rear end. The fuel device 3 is located within the air passage 11 and can be removed from the inlet 13. The combustion chamber at the front of the combustion chamber base 1 can extend into the furnace. Air enters the air passage 11 from the inlet 13 and is discharged into the furnace from the outlet 12. The combustion chamber base 1 isolates the fuel device 3 from the high temperature inside the furnace and cools it through the flowing air within the air passage.

[0037] like Figure 1 and Figure 4 As shown, the mixing device 2 is disposed at the front end of the combustion chamber base 1. The mixing device 2 includes a first mixing chamber 21 and several second mixing chambers 22. The first mixing chamber 21 is located in front of the air outlet 12, and the inner diameter of the first mixing chamber is larger than the inner diameter of the air outlet. The rear end of the first mixing chamber 21 is spaced apart from the air outlet 12, forming a first mixing zone 23 that communicates with the outside world to the side. Several second mixing chambers 22 are distributed in a ring around the outer periphery of the first mixing chamber 21. The front end of the second mixing chamber 22 extends from the front end of the first mixing chamber 21, and the rear end of the second mixing chamber 22 extends from the rear end of the first mixing chamber 21.

[0038] like Figure 3 As shown, the fuel device 3 includes a main fuel pipe 31, a tailstock 33, a flow divider valve core 35, an indicator bolt 36, and several fuel branch pipes 32. A burner head 34 is located at the front end of the main fuel pipe 31, positioned at the outlet 12, facing the rear end of the first mixing cylinder 21. Several fuel branch pipes 32 are arranged in a ring around the outer periphery of the main fuel pipe 31. The front ends of the fuel branch pipes 32 protrude at the front end of the combustion cylinder seat 1, as shown... Figure 2 As shown, the front end of the combustion chamber base 1 is provided with an outer conical surface 14 that tapers forward and towards the center. The rear end of the second mixing cylinder 22 faces the lower middle part of the outer conical surface 14. The front end of the fuel branch pipe 32 passes through the outer conical surface 14 and faces the rear end of the second mixing cylinder 22. The front ends of several fuel branch pipes 32 respectively face the rear ends of several second mixing cylinders 22, and the inner diameter of the second mixing cylinder 22 is larger than the inner diameter of the front ends of the fuel branch pipes 32.

[0039] like Figure 3As shown, the rear ends of the fuel main pipe 31 and the fuel branch pipes 32 are connected to the tail seat 33. The tail seat 33 is provided with a fuel cavity 331, and the rear ends of all the fuel branch pipes 32 are connected to the fuel cavity 331. A shunt valve core 35 is rotatably arranged at the rear of the tail seat 33, one end of the shunt valve core 35 extends into the fuel cavity 331 and is connected to the rear end of the fuel main pipe 31, and the shunt valve core 35 is provided with a shunt port 351 at the end extending into the fuel cavity 331, the shunt port 351 simultaneously connects the fuel main pipe 31 and the fuel cavity 331, the tail seat 33 is provided with a stopper 333 near the shunt port 351, and the shunt valve core 35 is rotated to change the shielding area of the stopper 333 to the shunt port 351; thereby controlling the fuel amount of the fuel cavity 331 entering the fuel main pipe.

[0040] As shown, Figure 3 the other end of the shunt valve core 35 is exposed to form an exposed end on the outer wall of the tail seat 33, the end face of the exposed end is provided with an arc-shaped groove 352, and the end face of the exposed end is provided with scales distributed along the arc-shaped groove 352, and the indicating bolt 36 is threadedly connected to the tail seat 22 after passing through the arc-shaped groove 352. Rotating the shunt valve core 35 from the exposed end of the shunt valve core can adjust the flow of the fuel shunt of the fuel cavity into the fuel main pipe 31 and the fuel branch pipe 32. When the flow is adjusted, the indicating bolt can read the shunt value according to the scales. Locking the indicating bolt can lock the shunt valve core on the tail seat 33, so that the shunt valve core cannot be rotated.

[0041] The combustion head 34 includes a cup body 342, a nozzle seat 341, and at least three nozzles 343, the opening of the cup body 342 faces forward, the front end of the nozzle seat 341 extends into the cup body 342, all the nozzles 343 are uniformly distributed on the front end of the nozzle seat 341, the outer end of the nozzle 343 extends obliquely to the outer edge of the cup body 342, the cup body 342 surrounds all the nozzles 343, and the rear end of the cup body 342 is provided with an air hole 344. The rear end of the nozzle seat 341 is connected to the front end of the fuel main pipe 31, the fuel in the fuel main pipe 31 is sprayed out through the nozzles to form a main flame, and the cup body and the air blown from the air hole 344 can shape the main flame.

[0042] As shown, Figure 1 the combustion cylinder seat 1 is provided with an air inlet pipe 6, one end of the air inlet pipe 6 extends into the air channel 11, the side of the tail seat 33 is provided with a plug 332, the plug 332 is sleeved with the air inlet pipe 6, the tail seat 33 is provided with a jack 5 at the back of the plug 332, the jack 5 is threadedly connected with the combustion cylinder seat 1, and rotating the jack 5 can push the tail seat 33 towards the air inlet pipe 6; so that the plug presses the air inlet pipe 6, and the fuel device is fixed in the air channel. One end of the jack 5 extends out of the side wall of the combustion cylinder seat 1 to form an extending end, the jack 5 is provided with a detection channel 51 which can communicate with the fuel cavity 331, and the detection channel 51 extends to the extending end. A pressure gauge or a pressure sensor is connected to the extending end of the jack 5, so as to detect the fuel pressure in the fuel cavity.

[0043] AsFigure 1 and Figure 2 As shown, the air passage 11 has a compression section 15 with a gradually decreasing inner diameter at its front, and the air outlet 12 is located at the front end of the compression section 15. An inner cylinder 41 is movable within the air passage 11 and is fitted around the outside of the burner head 34; the front end of the inner cylinder 41 can be moved to the front side of the burner head 34. An inner cylinder adjustment mechanism 42 is mounted on the burner seat 1 and is used to drive the inner cylinder 41 to move. The inner cylinder adjustment mechanism 42 includes a push-pull rod, a bolt seat, and an adjusting bolt. The bolt seat is mounted on the outer wall of the burner seat, and the adjusting bolt is threaded into the bolt seat. One end of the push-pull rod is connected to the inner cylinder, and the other end is hinged to the adjusting bolt. Rotating the adjusting bolt drives the inner cylinder to move back and forth. The inner cylinder can block the outer periphery of the front end of the burner head, thus changing the influence of the airflow at the air outlet on the main flame ejected from the burner head.

[0044] like Figures 1-4 As shown, a low-NOx combustion method for a burner includes the following steps:

[0045] The burner head 34 at the front end of the fuel main pipe 31 sprays fuel into the first mixing cylinder 21 and burns it to generate the main flame; the rear end of the first mixing cylinder 21 is separated from the burner head 34 by a first mixing zone 23 that communicates with the outside world on the side.

[0046] The burner head 34 is located inside the inner cylinder 41, which is located inside the air passage 11. The air passage 11 blows air into the first mixing cylinder 21 to assist the main flame combustion.

[0047] Several fuel branch pipes 32 distributed around the fuel main pipe 31 spray fuel into several second mixing cylinders 21 to generate several secondary flames. The rear end of the second mixing cylinder 21 is separated from the front end of the fuel branch pipe 32 to form a second mixing zone, which is located around the first mixing zone 23.

[0048] Move the front end of the inner cylinder 41 to the front side of the burner head 34 to adjust the shape of the main flame, so that the first mixing zone forms a suction force on the surrounding area and the second mixing zone.

[0049] The fuel main pipe 31 and fuel branch pipe 32 are controlled by a diversion valve core 35 to regulate the fuel distribution ratio. The burner is inserted into the furnace to burn fuel, and the nitrogen oxide content in the furnace air is monitored. The diversion valve core 35 is adjusted to control the fuel distribution ratio of the fuel main pipe 31 and fuel branch pipe 32. When the nitrogen oxide content in the furnace air is detected to be low, the adjustment of the diversion valve core 35 stops, the indicator bolt is tightened, and the adjustment function of the diversion valve core is fixed. The scale indicated by the indicator bolt can be applied to the same type of burner.

[0050] The above merely describes the preferred embodiments of the present application, and is not intended to limit the scope of the present application, and any equivalent changes and modifications made according to the scope of the present application should still fall within the scope of the present application.

Claims

1. A burner with low nitrogen emissions, characterized in that, The burner comprises a combustion cylinder base, a mixing device and a fuel device; the combustion cylinder base is provided with an air passage, and the air passage is provided with an air outlet at the front end of the combustion cylinder base; The mixing device is arranged at the front end of the combustion cylinder base, and comprises a first mixing cylinder and a plurality of second mixing cylinders; the first mixing cylinder is arranged in front of the air outlet, and a first mixing area is arranged between the rear end of the first mixing cylinder and the air outlet, and the first mixing area is in communication with the outside; The fuel device comprises a fuel main pipe and a plurality of fuel branch pipes arranged around the fuel main pipe; the front end of the fuel main pipe is provided with a combustion head, and the combustion head is arranged at the position of the air outlet and faces the rear end of the first mixing cylinder; the front ends of the fuel branch pipes respectively face the rear ends of the second mixing cylinders; The fuel device further comprises a tail base, a shunt valve core and an indicating bolt; the tail base is provided with a fuel cavity, and the rear ends of all the fuel branch pipes are in communication with the fuel cavity; The shunt valve core is rotatably arranged on the tail base, one end of the shunt valve core extends into the fuel cavity and is connected with the rear end of the fuel main pipe, the shunt valve core is provided with a shunt opening at the end extending into the fuel cavity, the shunt opening is in communication with the fuel main pipe and the fuel cavity, the tail base is provided with a stopper near the shunt opening, the shunt valve core can change the shielding area of the stopper to the shunt opening by rotation, the other end of the shunt valve core is exposed outside the wall of the tail base to form an exposed end, an arc-shaped groove is arranged on the end face of the exposed end, and a scale is arranged on the end face of the exposed end along the arc-shaped groove; the indicating bolt is screwed with the tail base through the arc-shaped groove.

2. A low nitrogen emission burner according to claim 1, characterized in that The fuel device is arranged in the air passage, the front ends of the fuel branch pipes are exposed at the front end of the combustion cylinder base, the air passage is provided with an air inlet at the rear end of the combustion cylinder base, and the fuel device can be removed from the air inlet.

3. A low nitrogen emission burner according to claim 1, wherein The burner further comprises an inner cylinder and an inner cylinder adjusting mechanism; the inner cylinder is movably arranged in the air passage and is sleeved with the combustion head; the inner cylinder adjusting mechanism is arranged on the combustion cylinder base and is used for driving the inner cylinder to move.

4. A low nitrogen emission burner according to claim 1, wherein The combustion cylinder base is provided with an air inlet pipe, one end of the air inlet pipe extends into the air passage, the side of the tail base is provided with a plug, the plug is sleeved with the air inlet pipe, the tail base is provided with a jack at the back of the plug, the jack is screwed with the combustion cylinder base, one end of the jack extends out of the side wall of the combustion cylinder base to form an extending end, and a detection channel in communication with the fuel cavity is arranged in the jack and extends to the extending end.

5. A low nitrogen emission burner according to claim 1, wherein The front end of the combustion cylinder base is provided with an outer tapered surface which is contracted forward and to the center, the rear end of the second mixing cylinder faces the middle and lower part of the outer tapered surface, and the front end of the fuel branch pipe faces the rear end of the second mixing cylinder after passing through the outer tapered surface; the front part of the air passage is provided with a compression section with gradually reduced inner diameter, and the air outlet is located at the front end of the compression section.

6. A low nitrogen emission burner according to claim 1, wherein The combustion head comprises a cup body, a nozzle seat and at least three nozzles; the opening of the cup body faces forward, the front end of the nozzle seat extends into the cup body, all the nozzles are arranged on the front end of the nozzle seat in a ring shape, the outer ends of the nozzles extend obliquely to the outer edge of the cup body, the cup body surrounds all the nozzles, and the rear end of the cup body is provided with a gas permeable hole.

7. A low nitrogen emission burner as claimed in claim 1, wherein The front end of the second mixing cylinder extends out of the front end of the first mixing cylinder, the rear end of the second mixing cylinder extends out of the rear end of the first mixing cylinder, the inner diameter of the first mixing cylinder is larger than the inner diameter of the air outlet, and the inner diameter of the second mixing cylinder is larger than the inner diameter of the front end of the fuel branch pipe.

8. A low-nitrogen combustion method of a combustor, characterized by, The burner is used for The method comprises the following steps: The combustion head at the front end of the fuel main pipe sprays fuel into the first mixing cylinder and produces a main flame by combustion; the rear end of the first mixing cylinder is spaced apart from the combustion head by a first mixing area which is in communication with the outside; The combustion head is arranged in the inner cylinder which is arranged in the air passage; the air passage blows air into the first mixing cylinder to assist the combustion of the main flame; A plurality of fuel branch pipes distributed around the outer periphery of the fuel main pipe respectively spray fuel into a plurality of second mixing cylinders to produce a plurality of secondary flames; the rear end of the second mixing cylinder is spaced apart from the front end of the fuel branch pipe by a second mixing area which is located at the outer periphery of the first mixing area; The front end of the inner cylinder is moved to the front side of the combustion head to adjust the shape of the main flame, so that the first mixing area forms suction to the periphery and the second mixing area; The fuel main pipe and the fuel branch pipe control the fuel distribution ratio by a flow distribution valve core; the burner is extended into the furnace to burn fuel; the nitrogen oxide content of the air in the furnace is monitored; the flow distribution valve core is adjusted to control the fuel distribution ratio of the fuel main pipe and the fuel branch pipe; when the nitrogen oxide content of the air in the furnace is detected to be at a low level, the adjustment of the flow distribution valve core is stopped, and the adjustment function of the flow distribution valve core is fixed.

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