Ammonia gas grading low-nitrogen burner for flue gas internal circulation

Abstract

The utility model discloses an ammonia gas grading low-nitrogen burner for flue gas internal circulation. The ammonia gas grading low-nitrogen burner structurally and sequentially comprises a first-stage gas spray gun, a flame stabilizing disc, an axial rotational flow blade, a second-stage gas spray gun, a rotational flow air cylinder, a direct flow air outlet, a direct flow air cylinder, a third-stage gas spray gun, an ammonia gas and flue gas mixing pipe and a cylinder which are coaxially arranged from the center to the outside. High-pressure ammonia gas fuel enters the high-pressure gas ring chamber from the high-pressure gas inlet, low-pressure ammonia gas fuel enters the low-pressure gas pipe from the low-pressure gas inlet, and three stages of fuel are achieved through the spray guns designed at different radial positions. Ammonia gas is used as main fuel, and reliable ignition of the ammonia gas is achieved through the light diesel oil ignition gun; when the temperature of the boiler hearth rises to 800 DEG C or above (exceeding the ignition temperature of the ammonia gas), the light diesel oil ignition gun stops working, and stable carbon-free low-nitrogen combustion of the pure ammonia gas in the boiler hearth is achieved through internal and external three-stage flue gas internal circulation and graded feeding of the ammonia gas and combustion-supporting air.

Description

Technical Field

[0001] The utility model belongs to the technical field of thermal energy engineering, and relates to an ammonia staged low-nitrogen burner with flue gas internal circulation, which is used for cleaning ammonia fuel boilers. Background Art

[0002] Ammonia (NH 3 ) can be synthesized by an electrochemical method, which can realize large-scale storage of renewable energy and zero carbon emissions of ammonia throughout its life cycle. Compared with hydrogen, ammonia has a large energy volume density, significant energy storage effect, and is easy to liquefy, store and transport. Its advantages in the renewable energy system are becoming increasingly obvious, making it a strong candidate for alternative fuels.

[0003] As a zero-carbon fuel, ammonia can be directly used as a boiler fuel. Compared with traditional fossil fuels, it can significantly reduce CO 2 emissions, providing a technical route for large-scale CO 2 emission reduction of boilers. However, there are two main technical problems when ammonia burns: (1) The combustion characteristics of NH 3 are poor, the ignition temperature is high, the flame propagation speed is slow, the flammable limit range is narrow, and there is a problem of whether NH 3 can be stably ignited and completely burned; (2) The NH 3 molecule contains nitrogen atoms. If the combustion process is not properly controlled, a large amount of fuel-type NOx (nitrogen oxides) is easily generated, resulting in a problem of high NOx emissions in the combustion flue gas.

[0004] At present, the combustion application of ammonia fuel has not been popularized, and the main applications are concentrated in fields such as internal combustion engines and gas turbines. There are few ammonia burners for boilers, and there is still room for further exploration in terms of reliable ignition, stable combustion of ammonia in boilers and reduction of NOx emissions.

[0005] Therefore, in order to realize the comprehensive utilization of zero-carbon ammonia energy, it is necessary to develop a new type of ammonia burner for ammonia fuel boilers to achieve "carbon-free combustion" while solving the problems of ignition, stable combustion and high NOx emissions existing in the ammonia combustion process. Summary of the Utility Model

[0006] The technical problem to be solved by the utility model is: to provide an ammonia staged low-nitrogen burner for flue gas internal circulation, which can use ammonia as a stable combustion fuel, enabling reliable ignition, stable combustion of ammonia and low NOx emissions, and the equipment structure is simple and compact, and it is convenient to install and use.

[0007] The technical solution adopted by the utility model is:

[0008] An ammonia staged low - nitrogen burner with flue gas internal circulation, mainly composed of a flame - stabilizing disc, axial swirl vanes, a primary gas spray gun, a secondary gas spray gun, a tertiary gas spray gun, a swirl air duct, a straight - through air duct, an ammonia and flue gas mixing pipe, a baffle, a burner housing, a cylinder, a high - pressure gas ring chamber, a low - pressure gas pipe, etc.

[0009] The swirl air duct and the straight - through air duct are coaxial with the burner housing and are placed in the inner cavity of the burner housing; the swirl air duct is coaxially provided with a primary gas spray gun, axial swirl vanes, and a secondary gas spray gun. The primary gas spray gun and the secondary gas spray gun are arranged at the outlet end of the swirl air duct. The primary gas spray gun is located at the axis of the swirl air duct, and the axial swirl vanes are located between the primary gas spray gun and the swirl air duct; there is a certain gap between the outer wall of the swirl air duct and the inner wall of the straight - through air duct to form a straight - through air outlet; several gas spray holes are evenly distributed on the circumference of the primary gas spray gun, and the gas spray holes face the radial direction of the swirl air duct; several secondary gas spray guns are circumferentially evenly distributed on the primary gas spray gun, and the gas spray holes face the axial direction of the swirl air duct; several tertiary gas spray guns are evenly arranged on the circumference of the primary gas spray gun outside the secondary gas spray gun, and an ammonia and flue gas mixing pipe is coaxially arranged outside each tertiary gas spray gun.

[0010] A flame - stabilizing disc is provided at the outlet of the primary gas spray gun. The top surface of the flame - stabilizing disc is a smooth plane, and the flame - stabilizing disc is connected to the end face of the primary gas spray gun. The gas outlet of the primary gas spray gun is located between the outlet of the axial swirl vanes and the end face of the swirl air duct.

[0011] The outlet end face of the secondary gas spray gun is flush with the axial swirl vanes it passes through. All the secondary gas spray guns are located on the same circumference and are evenly distributed.

[0012] The outlet of the tertiary gas spray gun is located 3 - 6 cm on the upwind side of the outlet of the ammonia and flue gas mixing pipe. A gas mixing section is formed between the outlet of the tertiary gas spray gun and the outlet of the ammonia and flue gas mixing pipe. All the tertiary gas spray guns are located on the same circumference and are evenly distributed.

[0013] A baffle is provided between the straight - through air duct and the cylinder. The baffle is located 30 - 45 cm away from the outlet of the straight - through air duct. The tertiary gas spray gun penetrates the baffle, and a low - pressure area is formed from the baffle to the gas outlet of the tertiary gas spray gun, so that the high - temperature flue gas in the middle combustion returns to the gas outlet of the tertiary gas spray gun.

[0014] The inlet of the ammonia and flue gas mixing pipe extends out of the outlet end of the cylinder by a distance of 8 - 15 cm. The outlet of the ammonia and flue gas mixing pipe extends out of the outlet end of the swirl air duct by a distance of 6 - 10 cm. The included angle between the axis of the outlet of the ammonia and flue gas mixing pipe and the axis of the swirl air duct is 10° - 20°, and the outlet of the ammonia and flue gas mixing pipe is far from the swirl air duct.

[0015] The outlet of the primary gas spray gun, the axial swirl vanes, and the secondary gas spray gun are all located inside the outlet of the swirl air duct.

[0016] The outlet of the straight-through air duct extends out of the outlet end of the cylinder, and the extending distance is 5 - 10 cm. The outlet of the straight-through air duct extending out of the cylinder is a conical reduced opening.

[0017] The blade angle of the axial swirl vanes is 50° - 65°, and the number of blades is 16 - 20.

[0018] On the burner housing, there are a high-pressure gas inlet, a low-pressure gas inlet, a high-pressure gas annular chamber, and a combustion-supporting air inlet; the combustion-supporting air inlet is connected to the cylinder; the high-pressure gas inlet is connected to the high-pressure gas annular chamber; the tertiary gas spray gun is connected to the high-pressure gas annular chamber; the low-pressure gas inlet is connected to the low-pressure gas pipe; both the primary gas spray gun and the secondary gas spray gun are connected to the low-pressure gas pipe. The low-pressure gas inlet, the high-pressure gas inlet, and the combustion-supporting air inlet are arranged on the outer wall of the burner housing to facilitate the connection of each gas pipe.

[0019] On the axial swirl vanes, there are reserved ignition gun mounting holes, flame observation holes, and flame detector mounting holes. The ignition gun adopts the form of a high-voltage electrode ignition gun using light diesel fuel to ignite the ammonia fuel sprayed by the primary gas spray gun and the secondary gas spray gun. When the furnace temperature rises to a certain temperature, the ignition gun goes out, and the ammonia is mixed with the high-temperature flue gas reflux in the boiler and ignited by the ammonia sprayed by the primary gas spray gun, the secondary gas spray gun, and the tertiary gas spray gun, ensuring the stable combustion of ammonia.

[0020] The number of radial spray holes of the primary gas spray gun is 8 - 12; the number of the secondary gas spray guns is 8 - 12; the number of the tertiary gas spray guns is 10 - 14, and nozzles are arranged at their outlets.

[0021] Compared with the prior art, the utility model has at least the following beneficial effects:

[0022] (1) This burner uses ammonia as the main fuel and is assisted by a small amount of light diesel. The reliable ignition of ammonia is achieved through the light diesel ignition gun; when the boiler furnace temperature rises above 800 °C (exceeding the ignition temperature of ammonia), the light diesel ignition gun stops working, and then through the internal and external three-stage flue gas internal circulation and the staged feeding of ammonia and combustion-supporting air, stable carbon-free and low-nitrogen combustion of pure ammonia can be achieved in the boiler furnace.

[0023] (2) Both the ammonia fuel and the combustion-supporting air are fed into the boiler furnace in a staged manner. Among them, the ammonia fuel is fed in three stages, and the combustion-supporting air is fed in two stages. Through the flame stabilizer and the axial swirl vanes, the high-temperature flue gas a near the primary gas spray gun flows back and turbulently mixes with the sprayed ammonia, realizing the formation of a stable combustion flame at the center of the burner.

[0024] (3) After the high-speed DC air at the outlet of the DC air duct is mixed with the recirculating high-temperature flue gas c, it is then mixed with the ammonia gas ejected from the secondary gas spray gun and burned, moderately extending the flame length, preventing the flame from concentrating, and being conducive to suppressing the generation of nitrogen oxides.

[0025] (4) The tertiary gas spray gun uses the induced-draft type to premix and recirculate the high-temperature flue gas b. In an oxygen-deficient environment, it enters the reduction area of the outer flame of the burner and reacts with the generated NOx in the high-temperature oxygen-deficient environment to generate N 3 and H 2 and H 2 O, further achieving the purpose of suppressing the generation of NOx. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Structural diagram of the ammonia staged low-nitrogen burner for flue gas internal circulation

[0027] Figure 2 Oblique view of the ammonia staged low-nitrogen burner for flue gas internal circulation

[0028] Figure 3 Partial cross-sectional view of the ammonia staged low-nitrogen burner for flue gas internal circulation

[0029] Figure 4 Cross-sectional view of the ammonia staged low-nitrogen burner for flue gas internal circulation

[0030] Among them, 1 is the flame stabilizing disc, 2 is the axial swirl vane, 3 is the secondary gas spray gun, 4 is the swirl air duct, 5 is the DC air duct, 6 is the ammonia and flue gas mixing pipe, 7 is the baffle, 8 is the combustion-supporting air inlet, 9 is the flame observation hole, 10 is the high-energy ignition gun installation hole, 11 is the flame detector installation hole, 12 is the DC air outlet, 13 is the low-pressure gas inlet, 14 is the high-pressure gas inlet, 15 is the burner housing, 16 is the cylinder, 17 is the tertiary gas spray gun, 18 is the high-pressure gas ring chamber, 19 is the low-pressure gas pipe, 20 is the burner installation on the boiler wall surface, and 21 is the primary gas spray gun. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The following further describes the present invention in detail with reference to the accompanying drawings.

[0032] As Figures 1 to 4As shown in the figure, the staged low-nitrogen burner with ammonia in the flue gas internal circulation of this embodiment includes, from the center outwards, a first-stage gas spray gun 21, a flame stabilizer 1, axial swirl vanes 2, a second-stage gas spray gun 3, a swirl air duct 4, a direct current air outlet 12, a direct current air duct 5, a third-stage gas spray gun 17, an ammonia and flue gas mixing pipe 6, and a cylinder 16 arranged coaxially. High-pressure ammonia fuel enters the high-pressure gas ring chamber 18 from the high-pressure gas inlet 14, and low-pressure ammonia fuel enters the low-pressure gas pipe 19 from the low-pressure gas inlet 13. The fuel is divided into three stages through spray guns designed at different radial positions respectively.

[0033] The first-stage gas spray gun 21 is coaxial with the swirl air duct 4 and is located at the central position. 8 to 12 gas spray holes are evenly distributed on the circumference of the first-stage gas spray gun 21. The gas spray holes face the radial direction of the swirl air duct 4. The gas outlet of the first-stage gas spray gun 21 is located between the outlet of the axial swirl vanes 2 and the end face of the swirl air duct.

[0034] The second-stage gas spray gun 3 is located inside the axial swirl vanes 2, and the end face of the second-stage gas spray gun 3 is flush with the corresponding axial swirl vanes 2 to maintain the swirl effect to the lowest degree. The number of the second-stage gas spray guns 3 can be set to 8 to 12 according to actual conditions. The gas spray holes of the second-stage gas spray gun 3 face the axial direction of the swirl air duct 4.

[0035] The third-stage gas spray gun 17 is located between the direct current air duct 5 and the cylinder 16. 10 to 14 third-stage gas spray guns 17 are evenly distributed along the circumferential direction according to actual conditions. A ammonia and flue gas mixing pipe 6 is coaxially arranged outside each third-stage gas spray gun 17.

[0036] A flame stabilizer 1 is provided at the outlet of the first-stage gas spray gun 21. The top surface of the flame stabilizer 1 is a smooth plane, forming a micro negative pressure recirculation zone, entraining part of the flame and high-temperature flue gas a, and forming a stable central flame near the first-stage gas spray gun 21.

[0037] After taking gas from the high-pressure gas ring chamber 18, the third-stage gas spray gun 17 is coaxially arranged with the inlet of the ammonia and flue gas mixing pipe 6. The outlet of the third-stage gas spray gun 17 is located 3 to 6 cm on the upwind side of the outlet of the ammonia and flue gas mixing pipe 6. A gas mixing section is formed between the outlet of the third-stage gas spray gun 17 and the outlet of the ammonia and flue gas mixing pipe 6. The inlet of the ammonia and flue gas mixing pipe 6 extends out of the outlet end of the cylinder 16, and the extending distance is 8 to 15 cm.

[0038] A baffle 7 is arranged between the direct current air duct 5 and the cylinder 16. The baffle 7 is located 30 to 45 cm from the outlet of the direct current air duct 5. The third-stage gas spray gun 17 penetrates through the baffle 7, forming a low-pressure area between the baffle 7 and the gas outlet of the third-stage gas spray gun 17, so that the high-temperature flue gas b and c in the middle combustion return to the gas outlet of the third-stage gas spray gun 17 and the outlet of the direct current air duct.

[0039] The outlet of the ammonia and flue gas mixing pipe 6 extends out of the outlet end of the swirling air duct 4, and the extension distance is 6 - 10 cm. The included angle between the axis of the outlet of the ammonia and flue gas mixing pipe 6 and the axis of the swirling air duct 4 is 10° - 20°. The outlet of the ammonia and flue gas mixing pipe 6 is far from the swirling air duct 4. After ammonia is ejected from the tertiary spray gun 17 at high speed, it entrains the surrounding high-temperature flue gas b, so as to preliminarily mix and preheat ammonia and high-temperature flue gas b in the mixing section of the ammonia and flue gas mixing pipe 6, reduce the flame temperature, enter the reduction area of the outer flame of the burner, and through the reduction reaction of NH3 with the generated NOx in the high-temperature oxygen-deficient environment, generate N 2 and H 2 O, further achieving the reduction of NOx generation.

[0040] After air enters through the combustion-supporting air inlet 8, it is finally divided into two levels to support combustion: The first-level combustion-supporting air is sent out by the axial swirling vane 2, which plays a role in stabilizing combustion at the center. Therefore, the axial swirling vane 2 is designed with strong swirl. The blade angle of the axial swirling vane 2 is 50° - 65°, and the number of blades is 16 - 20; The second-level combustion-supporting air is sent into the space between the swirling air duct 4 and the straight-through air duct at high speed, entraining the high-temperature flue gas c, moderately weakening the influence of the swirl on the tertiary gas spray gun 17, thereby delaying the combustion of part of the ammonia fuel, increasing the length and fullness of the flame in the furnace, reducing the combustion intensity, and forming an oxygen-deficient environment to send the ammonia ejected from the tertiary gas spray gun 17 into the reduction area of the outer flame of the burner. Through NH 3 In the high-temperature oxygen-deficient environment, it reacts with the generated NOx to generate N 2 and H 2 O, further achieving the reduction of NOx generation.

[0041] The outlet of the straight-through air duct 5 extends out of the outlet end of the cylinder 16, and the extension distance is 5 - 10 cm. The outlet of the straight-through air duct 5 extending out of the cylinder 16 is a conical constriction, which is beneficial to increasing the wind speed of the second-level combustion-supporting air and strengthening the entrainment of the high-temperature flue gas c.

[0042] The burner housing 15 is provided with a high-pressure gas inlet 14, a low-pressure gas inlet 13, a high-pressure gas annular chamber 18, and a combustion-supporting air inlet 8; The combustion-supporting air inlet 8 is communicated with the cylinder 16; The high-pressure gas inlet 14 is communicated with the high-pressure gas annular chamber 18; The tertiary gas spray gun 17 is communicated with the high-pressure gas annular chamber 18; The low-pressure gas inlet 13 is communicated with the low-pressure gas pipe 19; The primary gas spray gun 21 and the secondary gas spray gun are both communicated with the low-pressure gas pipe 19.

[0043] The axial swirling vane 2 is reserved with a spark plug mounting hole 10, a flame observation hole 9, and a flame detector mounting hole 11.

[0044] The ignition gun is in the form of a high-voltage electrode ignition gun using light diesel fuel, which ignites the ammonia fuel ejected from the primary gas spray gun 21 and the secondary gas spray gun 3. When the furnace temperature rises to a certain temperature, the ignition gun goes out. The high-temperature flue gas in the boiler flows back and mixes with the ammonia ejected from the primary gas spray gun 21, the secondary gas spray gun 3 and the tertiary gas spray gun 17, and then ignites the ammonia to ensure the stable combustion of ammonia.

[0045] It can be seen from the above scheme that the utility model has the following characteristics: (1) This burner uses ammonia as the main fuel and is assisted by a small amount of light diesel. The reliable ignition of ammonia is achieved through the light diesel ignition gun. When the boiler furnace temperature rises above 800 °C (exceeding the ignition temperature of ammonia), the light diesel ignition gun stops working. Then, through the internal and external three-stage flue gas internal circulation and the staged feeding of ammonia and combustion-supporting air, the stable carbon-free and low-nitrogen combustion of pure ammonia in the boiler furnace can be realized. (2) Both the ammonia fuel and the combustion-supporting air are fed into the boiler furnace in a staged manner. Among them, the ammonia fuel is fed in three stages, and the combustion-supporting air is fed in two stages. The high-temperature flue gas a near the primary gas spray gun flows back through the flame stabilization disk and the axial swirl vanes, and turbulently mixes with the ejected ammonia to form a stable combustion flame at the center of the burner. (3) After the high-speed direct current wind at the outlet of the direct current air duct mixes with the returned high-temperature flue gas c, it then mixes and burns with the ammonia ejected from the secondary gas spray gun, moderately extending the flame length, preventing the flame from concentrating, and being beneficial to suppressing the generation of nitrogen oxides. (4) The tertiary gas spray gun uses the ejected high-temperature flue gas b with premixed and returned injection. In an oxygen-deficient environment, it enters the reduction area of the outer flame of the burner and reacts with the generated NOx in the high-temperature oxygen-deficient environment to generate N 3 and H 2 O, further achieving the purpose of suppressing the generation of NOx. 2 O, further achieving the purpose of suppressing the generation of NOx.

Claims

1. An ammonia graded low-nitrogen burner with internal flue gas circulation, characterized in that: It comprises a flame stabilizing disk (1), an axial swirl blade (2), a first-stage gas spray gun (21), a second-stage gas spray gun (3), a third-stage gas spray gun (17), a swirl air cylinder (4), a DC air cylinder (5), an ammonia and flue gas mixing pipe (6), a baffle (7), a burner shell (15), and a cylinder (16); The swirl air cylinder (4) and the DC air cylinder (5) are coaxial with the burner housing (15) and are placed in the inner cavity of the burner housing (15); The cyclone duct (4) is coaxially provided with a primary gas spray gun (21), an axial cyclone blade (2), and a secondary gas spray gun (3); the primary gas spray gun (21) and the secondary gas spray gun (3) are arranged at the outlet end of the cyclone duct (4), and the primary gas spray gun (21) is located at the axis center of the cyclone duct (4); The axial swirl blade (2) is located between the first-stage gas spray gun (21) and the swirl wind tube (4); There is a certain gap between the outer wall of the cyclone air cylinder (4) and the inner wall of the DC air cylinder (5), and a DC air outlet (12) is formed; A baffle (7) is provided between the DC air cylinder (5) and the cylinder (16), and the three-stage gas spray gun (17) passes through the baffle (7), so that a low-pressure area is formed between the baffle (7) and the gas outlet of the three-stage gas spray gun (17), so that the high-temperature flue gas from the intermediate combustion flows back to the gas outlet of the three-stage gas spray gun (17); A plurality of first-stage gas spray guns (21) are evenly distributed on the circumference of the first-stage gas spray gun (21), and the gas spray holes of the first-stage gas spray gun (21) face the radial direction of the swirl wind tube (4); A plurality of secondary gas spray guns (3) are evenly distributed around the primary gas spray gun (21), and the gas spray holes of the secondary gas spray guns (3) face the axial direction of the swirl wind tube (4); A plurality of third-stage gas spray guns (17) are evenly arranged on the periphery of the second-stage gas spray gun (3) in the circumferential direction of the first-stage gas spray gun (21), and an ammonia and flue gas mixing pipe (6) is coaxially arranged on the periphery of each third-stage gas spray gun (17); the third-stage gas spray gun (17) is located between the DC air duct (5) and the cylinder (16).

2. The ammonia graded low-nitrogen burner with internal flue gas circulation according to claim 1 is characterized in that: A flame stabilizing plate (1) is provided at the outlet of the first-stage gas spray gun (21), the top surface of the flame stabilizing plate (1) is a smooth plane, and the flame stabilizing plate (1) is connected to the end surface of the first-stage gas spray gun (21); The gas outlet of the first-stage gas spray gun (21) is located between the outlet of the axial swirl blade (2) and the end surface of the swirl wind tube (4); The outlet end surface of the secondary gas spray gun (3) is flush with the axial swirl blade (2) passing through it; The outlet of the three-stage gas spray gun (17) is located 3 to 6 cm upwind of the outlet of the ammonia and flue gas mixing pipe (6). The outlet of the three-stage gas spray gun (17) is located between the outlets of the ammonia and flue gas mixing pipe (6) to form a gas mixing section.

3. The ammonia staged low nitrogen burner with internal flue gas circulation according to claim 1 is characterized in that: The inlet of the ammonia and flue gas mixing tube (6) extends out from the outlet end of the cylinder (16) by a distance of 8 to 15 cm; The outlet of the ammonia and flue gas mixing pipe (6) extends out from the outlet end of the cyclone fan (4) by a distance of 6 to 10 cm; The angle between the outlet axis of the ammonia and flue gas mixing pipe (6) and the axis of the cyclone fan (4) is 10° to 20°, and the outlet of the ammonia and flue gas mixing pipe (6) is far away from the cyclone fan (4).

4. The ammonia staged low nitrogen burner with internal flue gas circulation according to claim 1 is characterized in that: The outlet of the first-stage gas spray gun (21), the axial swirl blade (2) and the second-stage gas spray gun (3) are all located inside the outlet of the swirl wind tube (4).

5. The ammonia staged low nitrogen burner with internal flue gas circulation according to claim 1 is characterized in that: The outlet of the DC air duct (5) extends out from the outlet end of the cylinder (16) by a distance of 5 to 10 cm.

6. The ammonia staged low nitrogen burner with internal flue gas circulation according to claim 5, characterized in that: The outlet of the DC air cylinder (5) extends out of the cylinder (16) and is a conical outlet.

7. The ammonia staged low nitrogen burner with internal flue gas circulation according to claim 1 is characterized in that: The blade angle of the axial swirl blade (2) is 50° to 65°, and the number of blades is 16 to 20.

8. The ammonia staged low nitrogen burner with internal flue gas circulation according to claim 1, characterized in that: The burner casing (15) is provided with a high-pressure gas inlet (14), a low-pressure gas inlet (13), a high-pressure gas annular chamber (18), and a combustion-supporting air inlet (8); the combustion-supporting air inlet (8) is connected to the cylinder (16); the high-pressure gas inlet (14) is connected to the high-pressure gas annular chamber (18); the three-stage gas spray gun (17) is connected to the high-pressure gas annular chamber (18); the low-pressure gas inlet (13) is connected to the low-pressure gas pipe (19); the first-stage gas spray gun (21) and the second-stage gas spray gun are both connected to the low-pressure gas pipe (19).

9. The ammonia staged low nitrogen burner with internal flue gas circulation according to claim 1, characterized in that: The axial swirl blade (2) is reserved with an ignition gun mounting hole (10), a flame observation hole (9) and a flame detector mounting hole (11).

10. The ammonia staged low nitrogen burner with internal flue gas circulation according to claim 1, characterized in that: The number of radial spray holes of the first-stage gas spray gun (21) is 8 to 12; the number of the second-stage gas spray guns (3) is 8 to 12; and the number of the third-stage gas spray guns (17) is 10 to 14.

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