Graded ammonia spraying pulverized coal swirling burner

Abstract

The invention belongs to the technical field of combustors, and particularly discloses a graded ammonia spraying pulverized coal cyclone combustor which comprises a pre-combustion chamber, a main combustion chamber, an oil gun, a primary air pipe, an inner secondary air pipe, an outer secondary air pipe, a first-stage ammonia pipe and a second-stage ammonia pipe. The primary air pipe is arranged on the outer side of the oil gun, and the inner secondary air pipe is arranged on the outer side of the primary air pipe; the pre-combustion chamber is provided with a first top wall and a first side wall; the main combustion chamber is provided with a second top wall and a second side wall; the primary air pipe and the inner secondary air pipe are both communicated with the pre-combustion chamber; and the outer secondary air pipe is communicated with the main combustion chamber. The pre-combustion chamber is communicated with a first-stage ammonia gas pipe, the main combustion chamber is communicated with a second-stage ammonia gas pipe, ammonia gas input into the pre-combustion chamber is preferentially subjected to thermal cracking under the heating of first-stage flame, and the path that the ammonia gas is directly oxidized to generate nitrogen oxide is directly inhibited; secondary ammonia gas introduced into the main combustion chamber can be subjected to a neutralization reduction reaction with nitric oxide in the main combustion chamber, so that the ammonia gas is combusted more sufficiently, the burn-off rate is increased, and the emission of nitric oxide is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of burners, and particularly to a staged ammonia-injected pulverized coal swirl burner. Background Art

[0002] Ammonia is a hydrogen energy carrier with a mature preparation process and no carbon emissions after combustion, and can be used as a zero-carbon alternative fuel. However, ammonia has a high ignition energy, a narrow stable combustion limit range, and contains nitrogen itself. When co-fired with pulverized coal, problems such as difficult ignition and flameout, low burnout rate, and excessive nitrogen oxide emissions are likely to occur. Currently, in the prior art, Patent CN118066543A discloses an ammonia-coal co-firing burner that adjusts the mixing and ignition position of ammonia and rich / lean pulverized coal by changing the swing angle of the ammonia nozzle. Although this burner can achieve a more sufficient and stable co-combustion of coal, its combustion environment for ammonia remains the same, lacking the regulation of the local combustion environment in the burner, unable to make ammonia burn fully, and also resulting in problems such as low burnout rate and excessive nitrogen oxide emissions. Summary of the Invention

[0003] The object of the present invention is to provide a staged ammonia-injected pulverized coal swirl burner to solve the technical problems in the prior art that the combustion environment of ammonia remains the same, resulting in low burnout rate and excessive nitrogen oxide emissions.

[0004] To achieve the above object, the present invention provides a staged ammonia-injected pulverized coal swirl burner, which includes: a pre-combustion chamber, a main combustion chamber, an oil gun, a primary air duct, an inner secondary air duct, an outer secondary air duct, a primary ammonia pipe, and a secondary ammonia pipe; the oil gun, the pre-combustion chamber, and the main combustion chamber are arranged and connected in sequence along a first direction, the primary air duct is arranged outside the oil gun, and the inner secondary air duct is arranged outside the primary air duct; the pre-combustion chamber has a first top wall and a first side wall, and the first side wall is connected to the edge of the first top wall; the main combustion chamber has a second top wall and a second side wall, and the second side wall is connected to the edge of the second top wall; the first side wall is communicated with the second top wall;

[0005] The oil gun, the primary air duct, and the inner secondary air duct are all connected to the first top wall, and the primary air duct and the inner secondary air duct are both communicated with the pre-combustion chamber; the outer secondary air duct is arranged outside the inner secondary air duct, the outer secondary air duct is connected to the second top wall, and the outer secondary air duct is communicated with the main combustion chamber; the primary ammonia pipe is connected to the first side wall and is communicated with the pre-combustion chamber; the secondary ammonia pipe is connected to the second side wall and is communicated with the main combustion chamber.

[0006] Preferably, the oil gun is connected to the center of the first top wall.

[0007] Preferably, a first swirler is disposed inside the inner secondary air duct.

[0008] Preferably, the first swirler has a first rotating shaft and a plurality of first swirling vanes disposed around the first rotating shaft, and the included angle between the first swirling vanes and the first rotating shaft is 30 degrees to 60 degrees.

[0009] Preferably, a second swirler is disposed inside the outer secondary air duct.

[0010] Preferably, the second swirler has a second rotating shaft and a plurality of second swirling vanes disposed around the second rotating shaft, and the included angle between the second swirling vanes and the second rotating shaft is 30 degrees to 60 degrees.

[0011] Preferably, the shape of the pre-combustion chamber is cylindrical or a convex platform shape that gradually expands outward along the first direction.

[0012] Preferably, a plurality of first ammonia nozzles are provided on the first side wall, and the first ammonia nozzles are communicated with the primary ammonia pipe.

[0013] Preferably, the number of the first ammonia nozzles is 8 to 16, and the first ammonia nozzles are uniformly distributed around the central axis of the pre-combustion chamber.

[0014] Preferably, a plurality of second ammonia nozzles are provided on the second side wall, the second ammonia nozzles are communicated with the secondary ammonia pipe, and the second ammonia nozzles are provided with angle regulators for adjusting the spraying angle.

[0015] The staged ammonia injection pulverized coal swirl burner provided by the present invention has the following beneficial effects: The staged ammonia injection pulverized coal swirl burner has a pre-combustion chamber and a main combustion chamber. The pre-combustion chamber is communicated with the primary ammonia pipe, and the main combustion chamber is communicated with the secondary ammonia pipe. Since the air content in the pre-combustion chamber is insufficient, a fuel-rich environment is presented in the pre-combustion chamber. Therefore, the ammonia input into the pre-combustion chamber preferentially undergoes thermal cracking under the heating of the primary flame, that is, ammonia thermally cracks to produce hydrogen and nitrogen, directly inhibiting the path of ammonia being directly oxidized to form nitrogen oxides; moreover, the secondary ammonia introduced into the main combustion chamber can undergo a neutralization reduction reaction with nitric oxide in the main combustion chamber to generate nitrogen and water, thereby reducing the content of nitrogen oxides; therefore, ammonia is introduced into different combustion environments in stages, enabling ammonia to better participate in the reaction and combustion, making the combustion of ammonia more complete, improving the burnout rate, and reducing the nitrogen oxide emissions.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0017] Figure 1It is a schematic structural diagram of the staged ammonia injection pulverized coal swirl burner according to an embodiment of the present invention;

[0018] Figure 2 It is a schematic diagram of the flame distribution during the combustion of the staged ammonia injection pulverized coal swirl burner according to an embodiment of the present invention;

[0019] Figure 3 It is a schematic structural diagram when the pre - combustion chamber is in a convex - platform shape according to an embodiment of the present invention.

[0020] In the figure, 100, pre - combustion chamber; 110, first top wall; 120, first side wall; 121, first ammonia nozzle; 200, main combustion chamber; 210, second top wall; 220, second side wall; 221, second ammonia nozzle; 300, oil gun; 400, primary air duct; 500, inner secondary air duct; 510, first swirler; 600, outer secondary air duct; 610, second swirler; 700, primary ammonia pipe; 800, secondary ammonia pipe;

[0021] 10, primary flame; 20, secondary flame; 30, external high - temperature zone; 40, inner recirculation zone; 50, shear layer; 60, outer recirculation zone. Detailed implementation manners

[0022] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0023] In the description of the present invention, it should be understood that for the orientation description, such as up, down, front, back, left, right, etc., the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0024] In the description of the present invention, the meaning of several is one or more, the meaning of multiple is more than two, greater than, less than, exceeding, etc. are understood as not including the present number, above, below, within, etc. are understood as including the present number. If it is described as first and second, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or the sequence relationship of the indicated technical features.

[0025] In the description of the present invention, unless otherwise clearly defined, terms such as "arrangement", "installation", "connection", etc. shall be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0026] Please refer to Figures 1 to 3 together. Now, the staged ammonia injection pulverized coal swirl burner provided by the embodiments of the present invention will be described.

[0027] As Figures 1 to 2 shown, the staged ammonia injection pulverized coal swirl burner of the embodiment of the present invention includes a pre-combustion chamber 100, a main combustion chamber 200, an oil gun 300, a primary air duct 400, an inner secondary air duct 500, an outer secondary air duct 600, a primary ammonia pipe 700, and a secondary ammonia pipe 800; the oil gun 300, the pre-combustion chamber 100, and the main combustion chamber 200 are arranged and communicated in sequence along a first direction, the primary air duct 400 is arranged outside the oil gun 300, and the inner secondary air duct 500 is arranged outside the primary air duct 400; the pre-combustion chamber 100 has a first top wall 110 and a first side wall 120, and the first side wall 120 is connected to the edge of the first top wall 110; the main combustion chamber 200 has a second top wall 210 and a second side wall 220, and the second side wall 220 is connected to the edge of the second top wall 210; the first side wall 120 is communicated with the second top wall 210; the first direction is as Figure 1 shown by the X direction in

[0028] The oil gun 300, the primary air duct 400, and the inner secondary air duct 500 are all connected to the first top wall 110, and the primary air duct 400 and the inner secondary air duct 500 are both communicated with the pre-combustion chamber 100; the outer secondary air duct 600 is arranged outside the inner secondary air duct 500, the outer secondary air duct 600 is connected to the second top wall 210, and the outer secondary air duct 600 is communicated with the main combustion chamber 200; the primary ammonia pipe 700 is connected to the first side wall 120, and the primary ammonia pipe 700 is communicated with the pre-combustion chamber 100; the secondary ammonia pipe 800 is connected to the second side wall 220, and the secondary ammonia pipe 800 is communicated with the main combustion chamber 200.

[0029] The oil gun 300 plays a role of ignition and preheating during the cold start of the burner. The primary air duct 400 is used to transport the mixture of pulverized coal and air. A straight-section concentration ring of the boiler burner is arranged in the primary air duct 400, which can cause the concentration and dilution separation of pulverized coal particles, so that the concentrated-phase pulverized coal ignites preferentially at the outlet of the primary air duct 400, thereby improving the ignition stability of the pulverized coal.

[0030] The primary ammonia pipe 700 is used to evenly inject ammonia into the pre-combustion chamber 100. The ammonia is injected from the first side wall 120 of the pre-combustion chamber 100, which can better enable the ammonia to reach the external high-temperature zone 30 of the primary flame 10 in the pre-combustion chamber 100. Since the air content in the pre-combustion chamber 100 is insufficient and the overall atmosphere is fuel-rich, the primary ammonia preferentially undergoes thermal cracking rather than oxidation under the heating of the high-temperature pulverized coal flame. That is, the ammonia cracks to produce hydrogen and nitrogen, inhibiting the path of direct oxidation of ammonia to nitrogen oxides.

[0031] The working process of the staged ammonia injection pulverized coal swirl burner in this embodiment is as follows:

[0032] In the start-up stage of the burner, the oil gun 300 is put into use, that is, ignition and preheating are carried out to provide a heat source for the ignition of pulverized coal.

[0033] When the temperature of the pre-combustion chamber 100 reaches the ignition temperature of pulverized coal, the primary air duct 400, the inner secondary air duct 500, and the outer secondary air duct 600 are opened, and pulverized coal is fed into the primary air duct 400, so that the pulverized coal burns in the pre-combustion chamber 100 and the main combustion chamber 200 to form a pulverized coal flame; after the pulverized coal flame in the pre-combustion chamber 100 is stable, the oil gun 300 is closed. Among them, the fuel-air ratio (the mass ratio of fuel to air in the mixture) in the pre-combustion chamber 100 is relatively high, reducing the ignition temperature of pulverized coal and improving the ignition stability of pulverized coal. And the internal recirculation zone and the external recirculation zone generated by the secondary air duct in the main combustion chamber 200 can further improve the combustion stability of the pulverized coal flame in the main combustion chamber 200; at the same time, the axial distribution of the pre-combustion chamber 100 and the main combustion chamber 200 along the first direction is adopted, so that the pulverized coal burns in stages in the main combustion chamber 200 and the pre-combustion chamber 100, respectively forming a primary flame 10 and a secondary flame 20. Staged combustion can effectively reduce nitrogen oxides generated by pulverized coal combustion.

[0034] During ammonia-doped combustion, the ammonia is divided into two streams and sent into the pre-combustion chamber 100 and the main combustion chamber 200 through the primary ammonia pipe 700 and the secondary ammonia pipe 800 respectively. Among them, the primary ammonia pipe 700 sends ammonia into the pre-combustion chamber 100, and the secondary ammonia pipe 800 sends ammonia into the main combustion chamber 200. And the flow rate of the primary ammonia pipe 700 accounts for 70% to 90% of the total flow rate of the primary ammonia pipe 700 and the secondary ammonia pipe 800; the ammonia transported by the primary ammonia pipe 700 is injected from the first side wall 120 and directly contacts the external high-temperature zone 30 of the primary flame 10; since the air content in the pre-combustion chamber 100 is insufficient and the pre-combustion chamber 100 as a whole presents a fuel-rich environment, the ammonia input into the pre-combustion chamber 100 preferentially undergoes thermal cracking rather than oxidation reaction under the heating of the primary flame 10, that is, the ammonia thermally cracks to produce hydrogen and nitrogen, directly inhibiting the path of direct oxidation of ammonia to nitrogen oxides.

[0035] The outlet of the pre - combustion chamber 100 corresponds to the center of the main combustion chamber 200. The outlet of the pre - combustion chamber 100 is a mixture of components such as coke, carbon monoxide, carbon dioxide, water, ammonia, hydrogen, nitrogen, etc. After it enters the main combustion chamber 200, it will be mixed with the outer secondary air conveyed by the outer secondary air duct 600 and further oxidized and burned out, that is, a secondary flame 20 is generated in the main combustion chamber 200. At this time, nitrogen oxides are generated by two paths: thermal - type nitrogen oxides formed by the combustion of carbon monoxide and hydrogen, and fuel - type nitrogen oxides generated by the combustion of participating ammonia. Among them, due to the lack of oxygen at the outlet of the pre - combustion chamber 100, the nitrogen oxides formed in the internal recirculation zone 40 of the main combustion chamber 200 will be reduced by the remaining ammonia. Therefore, the nitrogen oxides in the main combustion chamber 200 mainly exist in the shear layer 50 of the outer secondary air and the outer recirculation zone 60.

[0036] According to the principle of selective non - catalytic reduction reaction, ammonia can undergo a neutralization reduction reaction with nitric oxide at a suitable temperature (900°C - 1100°C). Therefore, the secondary ammonia pipe 800 sprays ammonia into the main combustion chamber 200 from the second side wall 220, so that ammonia is mixed with the flue gas in the outer recirculation zone 60 and undergoes a selective non - catalytic reduction reaction, that is, ammonia reacts with nitric oxide to generate water and nitrogen, thereby reducing the generated nitrogen oxides to achieve the goal of low nitrogen oxide emissions.

[0037] The staged ammonia - injection pulverized - coal swirl burner of this embodiment has a pre - combustion chamber 100 and a main combustion chamber 200. The pre - combustion chamber 100 is connected to the primary ammonia pipe 700, and the main combustion chamber 200 is connected to the secondary ammonia pipe 800. Since the air content in the pre - combustion chamber 100 is insufficient, an environment rich in fuel exists in the pre - combustion chamber 100. Therefore, the ammonia input into the pre - combustion chamber 100 preferentially undergoes thermal cracking under the heating of the primary flame 10, that is, ammonia thermally cracks to produce hydrogen and nitrogen, directly inhibiting the path of ammonia being directly oxidized to form nitrogen oxides; moreover, the secondary ammonia introduced into the main combustion chamber 200 can undergo a neutralization reduction reaction with nitric oxide in the main combustion chamber 200 to generate nitrogen and water, thus reducing the content of nitrogen oxides; therefore, by injecting ammonia into different combustion environments in stages, ammonia can better participate in the reaction and combustion, making the combustion of ammonia more complete, improving the burnout rate, and reducing the nitrogen oxide emissions.

[0038] In some embodiments of the present invention, the oil gun 300 is connected to the center of the first top wall 110. That is, the oil gun 300 is aligned with the center of the pre - combustion chamber 100, so that the pulverized coal can burn at the center of the pre - combustion chamber 100; the pre - combustion chamber 100 is aligned with the center of the main combustion chamber 200, which can make the air flow more uniform for better swirl combustion.

[0039] In some embodiments of the present invention, a first swirler 510 is disposed inside the inner secondary air duct 500. The first swirler 510 is used to change the air flow structure of the inner secondary air in the inner secondary air duct 500, so that the inner secondary air becomes a swirling air flow, thereby reducing the axial velocity to better mix the fuel with the air.

[0040] In some embodiments of the present invention, the first swirler 510 has a first rotation axis (not shown in the figure) and a plurality of first swirl vanes (not shown in the figure) disposed around the first rotation axis. The angle between the first swirl vanes and the first rotation axis is 30 degrees to 60 degrees. The first rotation axis is parallel to the first direction, and the angle between the first swirl vanes and the first rotation axis is the axial angle. When the angle between the first swirl vanes and the first rotation axis is 30 degrees to 60 degrees, the combustion effect of the pre-combustion chamber 100 can be better, and the flame stability is good.

[0041] In some embodiments of the present invention, a second swirler 610 is disposed inside the outer secondary air duct 600. The second swirler 610 is used to change the air flow structure of the outer secondary air in the outer secondary air duct 600, so that the outer secondary air becomes a swirling air flow, thereby reducing the axial velocity to better mix the fuel with the air.

[0042] In some embodiments of the present invention, the second swirler 610 has a second rotation axis (not shown in the figure) and a plurality of second swirl vanes (not shown in the figure) disposed around the second rotation axis. The angle between the second swirl vanes and the second rotation axis is 30 degrees to 60 degrees. The second rotation axis is parallel to the first direction, and the angle between the second swirl vanes and the second rotation axis is the axial angle. When the angle between the second swirl vanes and the second rotation axis is 30 degrees to 60 degrees, the combustion effect of the main combustion chamber 200 can be better, and the flame stability is good.

[0043] In some embodiments of the present invention, the pre-combustion chamber 100 is cylindrical or in the shape of a convex platform that gradually expands outward along the first direction. When the pre-combustion chamber 100 is cylindrical, as Figure 1 shown, the shape of the first top wall 110 is circular, and the first side wall 120 is the side wall of a cylinder, so that the enclosed pre-combustion chamber 100 is cylindrical. This can make the flame burn more stably and more fully in the pre-combustion chamber 100.

[0044] When the pre-combustion chamber 100 is in the shape of a convex platform that gradually expands outward along the first direction, as Figure 3 shown, the shape of the first top wall 110 is circular, and the first side wall 120 is conical. This can make the air flow better spray out to both sides of the main combustion chamber 200, so that the fuel can better contact the air in the main combustion chamber 200 and improve the burnout rate.

[0045] In some embodiments of the present invention, a plurality of first ammonia nozzles 121 are provided on the first side wall 120, and the first ammonia nozzles 121 are communicated with the primary ammonia pipe 700. That is, the primary ammonia pipe 700 can use the plurality of first ammonia nozzles 121 to spray ammonia gas so that the ammonia gas can be sprayed more evenly towards the primary flame 10.

[0046] On the above basis, the number of the first ammonia nozzles 121 is 8 to 16, and the first ammonia nozzles 121 are uniformly distributed around the central axis of the pre-combustion chamber 100. The extending direction of the central axis of the pre-combustion chamber 100 is parallel to the first direction. The first ammonia nozzles 121 are uniformly distributed along the central axis of the pre-combustion chamber 100, which can make the primary ammonia gas be sprayed evenly towards the primary flame 10, make the ammonia gas burn more fully, and improve the burnout rate of ammonia.

[0047] In some embodiments of the present invention, a plurality of second ammonia nozzles 221 are provided on the second side wall 220. The second ammonia nozzles 221 are communicated with the secondary ammonia pipe 800, and the second ammonia nozzles 221 are provided with an angle adjuster (not shown in the figure) for adjusting the spraying angle. The spraying angle here is the included angle between the direction of the secondary ammonia gas ejected and the second side wall 220. The angle adjuster can be a universal joint to adjust the ejection direction of the second ammonia nozzle 221, so as to adjust the ejection direction of the secondary ammonia gas. Since the included angle between the second ammonia nozzle 221 and the second side wall 220 can be changed, the ejection direction can be adjusted according to the flame shape and the position of the external recirculation zone 60 under different ammonia blending ratios, so as to improve the burnout rate and reduce the emission of nitrogen oxides.

[0048] In summary, the staged ammonia injection pulverized coal swirl burner of this embodiment has a pre-combustion chamber 100 and a main combustion chamber 200. The pre-combustion chamber 100 is communicated with the primary ammonia pipe 700, and the main combustion chamber 200 is communicated with the secondary ammonia pipe 800. Since the air content in the pre-combustion chamber 100 is insufficient, an environment rich in fuel is presented in the pre-combustion chamber 100. Therefore, the ammonia gas input into the pre-combustion chamber 100 preferentially undergoes thermal cracking under the heating of the primary flame 10, that is, the ammonia gas undergoes thermal cracking to produce hydrogen and nitrogen, directly inhibiting the path of the ammonia gas being directly oxidized to form nitrogen oxides; moreover, the secondary ammonia gas introduced into the main combustion chamber 200 can undergo a neutralization reduction reaction with nitric oxide in the main combustion chamber 200 to generate nitrogen and water, so as to reduce the content of nitrogen oxides; therefore, the ammonia gas is introduced into different combustion environments in stages, enabling the ammonia gas to better participate in the reaction and combustion, making the ammonia gas burn more fully, improving the burnout rate, and reducing the emission of nitrogen oxides.

[0049] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A graded ammonia-injected coal powder swirl burner, characterized in that: include: A pre-combustion chamber, a main combustion chamber, an oil gun, a primary air duct, an inner secondary air duct, an outer secondary air duct, a primary ammonia pipe, and a secondary ammonia pipe; the oil gun, the pre-combustion chamber, and the main combustion chamber are arranged in sequence along a first direction and are connected, the primary air duct is arranged on the outside of the oil gun, and the inner secondary air duct is arranged on the outside of the primary air duct; the pre-combustion chamber has a first top wall and a first side wall, and the first side wall is connected to the edge of the first top wall; the main combustion chamber has a second top wall and a second side wall, and the second side wall is connected to the edge of the second top wall; the first side wall is connected to the second top wall; The oil gun, the primary air duct, and the inner secondary air duct are all connected to the first top wall, and the primary air duct and the inner secondary air duct are both connected to the pre-combustion chamber; the outer secondary air duct is arranged on the outside of the inner secondary air duct, and the outer secondary air duct is connected to the second top wall, and the outer secondary air duct is connected to the main combustion chamber; the first-level ammonia pipe is connected to the first side wall, and the first-level ammonia pipe is connected to the pre-combustion chamber; the second-level ammonia pipe is connected to the second side wall, and the second-level ammonia pipe is connected to the main combustion chamber.

2. The staged ammonia-injected pulverized coal swirl burner according to claim 1 is characterized in that: The oil gun is connected to the center of the first top wall.

3. The staged ammonia-injected pulverized coal swirl burner according to claim 1, characterized in that: A first cyclone is arranged in the inner secondary air duct.

4. The staged ammonia-injected coal powder swirl burner according to claim 3 is characterized in that: The first swirler has a first rotating shaft and a plurality of first swirling blades arranged around the first rotating shaft. The angle between the first swirling blades and the first rotating shaft is 30 degrees to 60 degrees.

5. The staged ammonia-injected pulverized coal swirl burner according to claim 1, characterized in that: A second cyclone is arranged in the outer secondary air duct.

6. The staged ammonia-injected pulverized coal swirl burner according to claim 5, characterized in that: The second swirler has a second rotation axis and a plurality of second swirling blades arranged around the second rotation axis, and the included angle between the second swirling blades and the second rotation axis is 30 degrees to 60 degrees.

7. The staged ammonia-injected pulverized coal swirl burner according to claim 1, characterized in that: The pre-combustion chamber is in a cylindrical shape or a boss shape that gradually expands outwards along the first direction.

8. The staged ammonia-injected pulverized coal swirl burner according to claim 1, characterized in that: The first side wall is provided with a plurality of first ammonia nozzles, and the first ammonia nozzles are communicated with the primary ammonia pipe.

9. The staged ammonia-injected pulverized coal swirl burner according to claim 8, characterized in that: The number of the first ammonia gas nozzles is 8 to 16, and the first ammonia gas nozzles are evenly distributed around the central axis of the pre-combustion chamber.

10. The staged ammonia-injected pulverized coal swirl burner according to claim 1, characterized in that: The second side wall is provided with a plurality of second ammonia nozzles, the second ammonia nozzles are communicated with the secondary ammonia pipe, and the second ammonia nozzles are provided with an angle adjuster for adjusting the injection angle.

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