A multi-stage ammonia-blended reverse-injection swirl burner and a method of using the same

Abstract

The present application discloses a multi-stage ammonia blending reverse jet swirl burner and a method of using the same, and relates to the technical field of clean and efficient utilization of coal. It includes a primary ammonia blending mechanism, a secondary ammonia blending mechanism, a primary air and powder guide tube, a tertiary ammonia blending mechanism, a secondary air guide tube, a transition channel outer tube, a stable combustion chamber, and a reflux cap; the primary ammonia blending mechanism is arranged in the primary air and powder guide tube, the secondary ammonia blending machine runs through the primary ammonia blending mechanism and the reflux cap, and the tertiary ammonia blending mechanism runs through the closed transition channel. The present application sets up primary, secondary, and tertiary ammonia blending mechanisms, which realizes the mixed combustion of ammonia in different stages of coal powder combustion, improves the adjustment range of the blending ratio, and reduces the nitrogen combustion effect.

Description

Technical Field

[0001] The present application relates to the technical field of clean and efficient utilization of coal, and in particular to a multi-stage ammonia-blended reverse-injection swirl burner and a method for using the same. Background Art

[0002] At present, in the field of pulverized coal power plants and industrial boilers, ammonia is gradually being mixed and burned as a carbon-free fuel in various burners such as swirl burners, direct current burners, blunt body burners, air staged burners and reverse injection burners, aiming to reduce the carbon emission intensity of pulverized coal boilers. The common feature of the mixing is that the ammonia jet is directly sent into the combustion area through a spray gun or sent into the primary air duct to mix with coal powder and then enter the combustion area, so as to achieve stable, efficient and low-nitrogen combustion effect of coal powder mixed with ammonia.

[0003] However, due to the low activity of ammonia fuel and the relatively simple blending method, the ignition and violent combustion process of the mixed fuel inside the burner and at the outlet is limited to a small range of adjustment of the operating parameters and the blending ratio. Therefore, there is a small proportion of ammonia blending and combustion in pulverized coal boilers, and the carbon emission intensity reduction is limited, which makes it impossible to achieve large-scale promotion and application. At the same time, the large proportion of blending and the nitrogen element contained in ammonia make it difficult to ignite, difficult to stabilize combustion and have high nitrogen oxide emissions. Summary of the invention

[0004] In response to the above problems, one object of the present application is to provide a multi-stage ammonia-doped reverse-injection swirl coal powder burner with diverse mixing methods and a wide mixing ratio range; another object of the present application is to provide a method for using the multi-stage ammonia-doped reverse-injection swirl coal powder burner.

[0005] The first object of the present application is to provide a multi-stage ammonia-blended reverse injection swirl burner adopting the following technical solution:

[0006] A multi-stage ammonia-doped reverse-jet swirl burner comprises a primary ammonia-doped mechanism, a secondary ammonia-doped mechanism, a primary air powder guide tube, a tertiary ammonia-doped mechanism, a secondary air guide tube, a transition channel outer tube, a combustion stabilization chamber and a reflux cap;

[0007] The secondary air guide cylinder and the combustion stabilizing chamber are connected to form a burner body, the transition channel outer cylinder is arranged in the secondary air guide cylinder, and a secondary air channel is formed between the transition channel outer cylinder and the secondary air guide cylinder;

[0008] The primary air powder guide tube is arranged through the burner body, the primary air powder guide tube and the transition channel outer tube form a closed transition channel, and the reflux cap is arranged at the outlet end of the primary air powder guide tube;

[0009] The first-stage ammonia blending mechanism is arranged in the primary air powder guide tube, the second-stage ammonia blending machine is arranged through the first-stage ammonia blending mechanism and the reflux cap, and the third-stage ammonia blending mechanism is arranged through the closed transition channel.

[0010] By adopting the above technical solution, setting up the first, second and third stage ammonia blending mechanism, the mixed combustion of ammonia in different stages of coal powder combustion is realized, the adjustment range of the blending ratio is improved, and the nitrogen combustion effect is reduced. The first stage ammonia can be initially ignited and burned with the reverse primary air powder, the second stage ammonia is heated by the high temperature flue gas reflux in the furnace, and forms a stable combustion process with the main flame in the furnace, and the third stage ammonia is preheated and heated in the high temperature reflux zone, and forms a stable combustion process with the main flame.

[0011] Preferably, it also includes a cyclone arranged in the secondary air channel.

[0012] By adopting the above technical solution and arranging a cyclone in the secondary air channel, the secondary air in the secondary air guide tube can form a rotating airflow with a tangential velocity after passing through the secondary air channel, effectively improving the mixing uniformity of coal powder and ammonia.

[0013] Preferably, an inspection hole is provided at the elbow of the primary air powder guide tube, and the first-level ammonia blending mechanism is penetrated in the primary air powder guide tube along the inspection hole.

[0014] By adopting the above technical scheme, an inspection hole is set at the elbow of the primary air powder guide tube, and the first-level ammonia mixing mechanism extends into the primary air powder guide tube along the inspection hole. The inspection hole provides a channel for the first-level ammonia mixing mechanism to enter the primary air powder guide tube. At this position, the wear of the first-level ammonia mixing mechanism and the vertical section of the primary air powder guide tube can be effectively avoided, thereby improving the service life. In addition, the inspection hole can be used to check and observe whether the inside of the burner is operating normally, thereby facilitating maintenance.

[0015] Preferably, the primary ammonia blending mechanism comprises a primary ammonia blending pipeline, the primary ammonia blending pipeline extends into the primary air guide cylinder, and the outlet end of the primary ammonia blending pipeline has eight primary ammonia spray holes evenly distributed along the circumferential direction.

[0016] By adopting the above technical solution, eight primary ammonia spray holes are evenly distributed along the circumferential direction at the outlet end of the primary ammonia blending pipeline, and the primary ammonia is more evenly distributed when entering the primary air guide tube through the primary ammonia blending pipeline.

[0017] Preferably, the secondary ammonia blending mechanism comprises a secondary ammonia blending pipeline, the secondary ammonia blending pipeline is arranged inside the primary ammonia blending pipeline, and the secondary ammonia blending pipeline has four secondary ammonia spray holes evenly distributed in the circumferential direction.

[0018] By adopting the above technical solution, four secondary ammonia spray holes are evenly distributed along the circumference at the outlet end of the secondary ammonia blending pipeline, and the secondary ammonia gas is more evenly distributed when entering the flame center inside the furnace through the secondary ammonia blending pipeline.

[0019] Preferably, the three-stage ammonia blending mechanism includes a three-stage ammonia blending pipeline, the three-stage ammonia blending pipeline is connected to a plurality of three-stage ammonia blending branches, the plurality of three-stage ammonia blending branches are all arranged in the closed transition channel, and the plurality of three-stage ammonia blending branches are arranged around the inner circumference of the closed transition channel.

[0020] By adopting the above technical solution, multiple tertiary ammonia blending branches are arranged around the inner circumference of the closed transition channel, so that the tertiary ammonia can enter the stable combustion chamber more evenly, improving combustion efficiency.

[0021] Preferably, a buffer coil is connected between the tertiary ammonia blending pipeline and the multiple tertiary ammonia blending branches, and the axial direction of the buffer coil is arranged along the axial direction of the outer tube of the transition channel; the tertiary ammonia blending pipeline is vertically fixedly connected to the buffer coil, and the multiple tertiary ammonia blending branches are circumferentially distributed on the buffer coil.

[0022] By adopting the above technical solution, a buffer coil is set between the tertiary ammonia blending pipeline and multiple tertiary ammonia blending branches, which can effectively stabilize the ammonia pressure and reduce the uneven airflow distribution.

[0023] Preferably, one end of the tertiary ammonia-doping branch away from the buffer coil extends into the combustion stabilization chamber, and a plurality of gas diffusion zones are arranged on the side wall of the tertiary buffer coil extending into the combustion stabilization chamber at intervals along the flow direction of ammonia gas. Each of the gas diffusion zones includes a plurality of diffusion holes arranged at intervals around the corresponding side of the tertiary ammonia-doping branch. The diffusion holes are arranged obliquely toward the combustion stabilization chamber, and the diameters of the diffusion holes in the plurality of diffusion zones arranged sequentially at intervals along the flow direction of ammonia gas gradually decrease.

[0024] By adopting the above technical solution, when ammonia moves along the three-stage ammonia-doped branch, part of the ammonia is sprayed into the stable combustion chamber through multiple gas diffusion zones in turn, and the remaining ammonia enters the stable combustion chamber along the outlet of the three-stage ammonia-doped branch. Ammonia enters the stable combustion chamber from different parts to avoid the dangerous situation caused by excessive concentration of ammonia in a single area due to excessive temperature. In addition, since the diameter of the diffusion holes in the gas diffusion zones arranged at intervals along the flow direction of ammonia gradually increases, the initial speed of ammonia sprayed from different gas diffusion zones is different, and the maximum spray distance is also different, making the diffusion range of ammonia wider. Moreover, the different ammonia flows sprayed from different three-stage ammonia-doped branches collide with each other, further increasing the diffusion range of ammonia and the degree of mixing with the nested high-temperature flue gas reflux, effectively enhancing the preheating efficiency and combustion effect.

[0025] Another object of the present application is to provide a method for using the above-mentioned multi-stage ammonia-doped reverse injection swirl burner using the following technical solution:

[0026] A method for using a multi-stage ammonia-doped reverse-injection swirl burner comprises the following steps:

[0027] (1) Air is introduced from the secondary air guide tube, passes through the cyclone in the secondary air channel to form a rotating airflow with a tangential velocity and all enters the stable combustion chamber, and the rotating airflow and the outer tube of the transition channel work together to form a nested high-temperature flue gas reflow; the swirl number of the rotating airflow generated by the cyclone should be controlled between 1.0-2.0, and the wind speed of the secondary air should be controlled within the range of 25-45m / s;

[0028] (2) The air carrying coal powder is introduced from the primary air powder guide tube, and the primary ammonia enters the primary air powder guide tube through the primary ammonia blending mechanism to form a mixture of primary air powder and primary ammonia; the input heat of the primary ammonia should be controlled within the range of 0-20% of the total input heat;

[0029] (3) The primary air powder and primary ammonia mixture enters the stable combustion chamber in reverse under the action of the reflux cap, and is preheated and ignites under the action of the high-temperature flue gas reflux to form a primary flame. After the reverse movement ends, it forms a main flame with the rotating airflow of the secondary air channel, and rotates and burns in the stable combustion chamber with it;

[0030] (4) The main flame of the swirling incineration forms a high-temperature flue gas reflux again at the outlet of the stable combustion chamber and behind the reflux cap. The secondary ammonia enters the high-temperature flue gas reflux through the secondary ammonia mixing mechanism. The input heat of the secondary ammonia should be controlled within the range of 0%-50% of the total input heat. The secondary ammonia is rapidly heated and cracked to form high-temperature combustibles for stable combustion with the main flame; the tertiary ammonia enters the nested high-temperature flue gas reflux through the tertiary ammonia mixing mechanism, is fully preheated and heated, and then mixed into the main flame for combustion; and the input heat of the tertiary ammonia should be controlled within the range of 0%-30% of the total input heat.

[0031] By adopting the above technical scheme, the ammonia mixing ratio in different stages of pulverized coal combustion is controlled, with little impact on the original flow field organizations such as reverse jet, rotating jet, and blunt body reflux, without breaking the original combustion organization characteristics. There is no need to make major changes to the original pulverized coal burner structure design and operating conditions, reducing the difficulty of technical transformation of ammonia-coal mixed combustion in pulverized coal boilers.

[0032] Preferably, when adjusting the ammonia blending ratio, it is first necessary to gradually reduce the original coal powder supply rate and reduce the coal powder concentration in the primary air-powder mixture. After a stable combustion process is formed, different ammonia blending mechanisms are selected to be opened according to the ammonia blending ratio requirements:

[0033] When the ammonia blending ratio is less than 20%, use the primary ammonia blending mechanism, the secondary ammonia blending mechanism or the tertiary ammonia blending mechanism alone;

[0034] When the ammonia blending ratio is 20%-60%, any two of the first-stage ammonia blending mechanism, the second-stage ammonia blending mechanism and the third-stage ammonia blending mechanism are turned on, or all three ammonia blending mechanisms are turned on at the same time;

[0035] When the ammonia mixing ratio is >60%, the first-stage ammonia mixing mechanism, the second-stage ammonia mixing mechanism and the third-stage ammonia mixing mechanism are opened at the same time.

[0036] In summary, the present application includes at least one of the following beneficial technical effects:

[0037] 1. The first-level, second-level and third-level ammonia blending mechanisms are set up to achieve the mixed combustion of ammonia at different stages of coal powder combustion, improve the adjustment range of the blending ratio, and reduce the nitrogen combustion effect. The first-level ammonia can be initially ignited and burned with the reverse primary air powder, the second-level ammonia is heated by the high-temperature flue gas reflux in the furnace, and forms a stable combustion process with the main flame in the furnace, and the third-level ammonia is preheated in the high-temperature reflux zone and forms a stable combustion process with the main flame;

[0038] 2. When ammonia moves along the three-stage ammonia-doped branch, part of the ammonia is sprayed into the stable combustion chamber through multiple gas diffusion zones in turn, and the remaining ammonia enters the stable combustion chamber along the outlet of the three-stage ammonia-doped branch. Ammonia enters the stable combustion chamber from different parts to avoid dangerous situations caused by excessive concentration of ammonia and excessive temperature in a single area. In addition, since the diameter of the diffusion holes in the gas diffusion zones arranged at intervals along the flow direction of ammonia gradually increases, the initial velocities of ammonia sprayed from different gas diffusion zones are different, and the maximum spray distances are also different, making the diffusion range of ammonia wider. Moreover, the different ammonia flows sprayed from different three-stage ammonia-doped branches collide with each other, further increasing the diffusion range of ammonia and the degree of mixing with the nested high-temperature flue gas reflux, effectively enhancing the preheating efficiency and combustion effect;

[0039] 3. The method used in this application realizes the control of the ammonia mixing ratio at different stages of coal powder combustion, has little impact on the original flow field organizations such as reverse jet, rotating jet, and blunt body reflux, does not break the original combustion organization characteristics, and does not require major changes to the original coal powder burner structure design and operating conditions, thereby reducing the difficulty of technical transformation of ammonia-coal mixed combustion of coal powder boilers. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present application.

[0041] Figure 2 It is an overall structural diagram showing the positional relationship among the primary ammonia doping mechanism, the secondary ammonia doping mechanism and the tertiary ammonia doping mechanism in the embodiment of the present application.

[0042] Figure 3 It is a cross-sectional structural schematic diagram showing the positional relationship between the primary ammonia doping mechanism and the secondary ammonia doping mechanism in the embodiment of the present application.

[0043] Figure 4 It is a schematic cross-sectional structure diagram showing the three-stage ammonia blending mechanism in the embodiment of the present application.

[0044] Figure 5 It is a schematic diagram of the cross-sectional structure of the three-stage ammonia blending pipeline in the embodiment of the present application.

[0045] Explanation of the reference numerals: 1. primary ammonia doping mechanism; 11. primary ammonia doping pipeline; 12. primary ammonia gas spray hole; 2. secondary ammonia doping mechanism; 21. secondary ammonia doping pipeline; 22. secondary ammonia gas spray hole; 3. primary air powder guide tube; 31. inspection hole; 4. tertiary ammonia doping mechanism; 41. tertiary ammonia doping pipeline; 42. buffer coil; 43. tertiary ammonia doping branch; 44. gas diffusion zone; 441. diffusion hole; 5. secondary air guide tube; 6. transition channel outer tube; 7. cyclone; 8. combustion stabilization chamber; 9. reflux cap. DETAILED DESCRIPTION

[0046] The following is combined with Figure 1-5 This application is described in further detail.

[0047] The embodiments of the present application disclose a multi-stage ammonia-blended reverse-injection swirl burner and a method of using the same.

[0048] Example

[0049] Reference Figure 1 A multi-stage ammonia-doped reverse-jet swirl burner comprises a primary ammonia-doping mechanism 1, a secondary ammonia-doping mechanism 2, a primary air-powder guide tube 3, a tertiary ammonia-doping mechanism 4, a secondary air-guide tube 5, a transition channel outer tube 6, a swirler 7, a stable combustion chamber 8, a reflux cap 9 and an inspection hole 31 arranged at the elbow of the primary air-powder guide tube 3.

[0050] The secondary air guide tube 5 is connected with the combustion stabilization chamber 8 to form the burner body, and the transition channel outer tube 6 is arranged inside the secondary air guide tube 5. The primary air powder guide tube 3 is arranged to pass through the central axis of the burner body. The reflux cap 9 is arranged outside the outlet of the primary air powder guide tube 3. The primary ammonia mixing mechanism 1 is arranged at the central axis position of the inspection hole 31. The secondary ammonia mixing mechanism 2 passes through the central axis position of the primary ammonia mixing mechanism 1 and the reflux cap 9.

[0051] A closed transition channel is formed between the primary air powder guide tube 3 and the transition channel outer tube 6. A secondary air channel is formed between the secondary air guide tube 5 and the transition channel outer tube 6. The three-stage ammonia blending mechanism 4 is arranged throughout the closed transition channel. The first-stage ammonia blending mechanism 1, the second-stage ammonia blending mechanism 2 and the third-stage ammonia blending mechanism 4 jointly realize multi-stage blending of ammonia gas, forming a stable mixed combustion process of ammonia coal.

[0052] Combination Figure 2 and Figure 3 The primary ammonia blending mechanism 1 includes a primary ammonia blending pipeline 11, one end of which extends into the primary air-powder guide tube 3 and is welded and fixed at the center of the flange cover of the inspection hole 31. The primary ammonia blending pipeline 11 is used to transport primary ammonia. Eight primary ammonia spray holes 12 are evenly spaced along the circumference of the port of the primary ammonia blending pipeline 11, so that the primary ammonia jet is evenly mixed into the primary air-powder mixture in the primary air-powder guide tube 3 along the eight primary ammonia spray holes 12.

[0053] The secondary ammonia mixing mechanism 2 includes a secondary ammonia mixing pipeline 21, which is fixed in the primary ammonia mixing pipeline 11 and the central axis position of the reflux cap 9 at the same time, and is used to transport secondary ammonia. Four secondary ammonia gas spray holes 22 are evenly spaced along the circumference of the secondary ammonia mixing pipeline 21, so that the secondary ammonia gas jet is evenly sprayed into the center of the flame inside the furnace along the four secondary ammonia gas spray holes 22.

[0054] Reference Figure 1 The reflux cap 9 is welded and fixed at the outlet of the primary air powder guide tube 3 by using a uniformly distributed cylindrical fixing piece. The reflux cap 9 hinders the continued direct flow of the mixture of primary air powder and primary ammonia gas flowing out of the primary air powder guide tube 3, thereby forcing the mixture of primary air powder and primary ammonia gas to reversely enter the stable combustion chamber 8 along the gaps of the four cylindrical fixing pieces.

[0055] Combination Figure 2 and Figure 4 The three-stage ammonia blending mechanism 4 includes a three-stage ammonia blending pipeline 41, and the three-stage ammonia blending pipeline 41 is used to transport three-stage ammonia. The three-stage ammonia blending pipeline 41 is fixedly connected with a buffer coil 42, and the buffer coil 42 is a circular tube. The axial direction of the buffer coil 42 is arranged along the axial direction of the outer tube 6 of the transition channel, and the three-stage ammonia blending pipeline 41 is arranged perpendicular to the axial direction of the buffer coil 42. The buffer coil 42 can stabilize the ammonia pressure and reduce the uneven distribution of the airflow. The buffer coil 42 is evenly spaced in the circumferential direction and connected with four three-stage ammonia blending branches 43. The axial direction of the four three-stage ammonia blending branches 43 is arranged along the axial direction of the buffer coil 42, and the four three-stage ammonia blending branches 43 are all fixed in the closed transition channel through stainless steel pipes, so that the three-stage ammonia enters the stable combustion chamber 8 more evenly.

[0056] Combination Figure 1 and Figure 5One end of the tertiary ammonia-doped branch 43 away from the buffer coil 42 extends into the combustion stabilization chamber 8, and a plurality of gas diffusion zones 44 are arranged at intervals along the gas flow direction on the side wall of the tertiary ammonia-doped branch 43 extending into the combustion stabilization chamber 8, and each gas diffusion zone 44 includes a plurality of diffusion holes 441 arranged at intervals around the circumference of the tertiary ammonia-doped branch 43, and the axial direction of the diffusion hole 441 is inclined toward the combustion stabilization chamber 8, and the diameter of the diffusion hole 441 in the gas diffusion zone 44 closer to the reflux cap 9 is larger.

[0057] When ammonia moves along the three-stage ammonia-doped branch 43, part of the ammonia is sprayed into the stable combustion chamber 8 through multiple gas diffusion zones 44 in turn, and the remaining ammonia enters the stable combustion chamber 8 along the outlet of the three-stage ammonia-doped branch 43. Ammonia enters the stable combustion chamber 8 from different parts to avoid the dangerous situation caused by excessive concentration of ammonia in a single area due to excessive temperature. In addition, since the diameter of the diffusion holes 441 in the gas diffusion zones 44 arranged at intervals along the flow direction of ammonia gradually increases, the initial speed of ammonia sprayed from different gas diffusion zones 44 is different, and the maximum spray distance is also different, making the diffusion range of ammonia wider. In addition, different ammonia flows sprayed from different three-stage ammonia-doped branches 43 collide with each other, further increasing the diffusion range of ammonia and the degree of mixing with the nested high-temperature flue gas reflux, effectively enhancing the preheating efficiency and combustion effect.

[0058] Reference Figure 1 The closed transition channel is provided with an igniter / or flame detector. The transition channel outer tube 6 is a cylindrical blunt body, and the igniter / or flame detector is arranged between the four three-stage ammonia blending branches 43.

[0059] The cyclone 7 is arranged in the secondary air channel, and is used to make the secondary air in the secondary air guide tube 5 form a rotating airflow with a tangential velocity after passing through the cyclone 7. In the embodiment of the present application, the cyclone 7 includes a plurality of axial swirl blades, which are in the shape of double helices and have a fixed angle, and are uniformly arranged in the circumferential direction in the secondary air channel and are welded and fixed to the transition channel outer tube 6 and the secondary air guide tube 5.

[0060] The implementation principle of the above embodiment is:

[0061] First, air is introduced from the secondary air guide tube 5. The air passes through the cyclone 7 in the secondary air channel to form a rotating airflow with a tangential velocity and all enters the stable combustion chamber 8. The rotating airflow and the transition channel outer tube 6 work together to form a nested high-temperature flue gas reflux. Then, air carrying coal powder is introduced from the primary air powder guide tube 3, and the primary ammonia enters the primary air powder guide tube 3 at the inspection hole 31 through the primary ammonia pipeline and the primary ammonia nozzle 12, forming a mixture of primary air powder and primary ammonia. The primary air powder and primary ammonia mixture enters the stable combustion chamber 8 in reverse under the action of the reflux cap 9, and is preheated and ignited under the action of the high-temperature flue gas reflux to form a primary flame. After the reverse motion is completed, it forms a main flame with the rotating airflow of the secondary air channel, and swirls and burns with it in the stable combustion chamber 8. The main flame of the swirling combustion forms a high-temperature flue gas reflux again at the outlet of the stable combustion chamber 8 and behind the reflux cap 9. The secondary ammonia enters the high-temperature flue gas reflux through the secondary ammonia pipeline and the secondary ammonia spray hole 22. The secondary ammonia is rapidly heated and cracked to form high-temperature combustibles for stable combustion with the main flame. Finally, the tertiary ammonia enters the nested high-temperature flue gas reflux through the tertiary ammonia pipeline and the tertiary ammonia spray hole, and is fully preheated and heated before being mixed into the main flame for combustion.

[0062] The mixed combustion of ammonia in different stages of pulverized coal combustion is realized, and at the same time, the ammonia mixing ratio is controlled in different stages of pulverized coal combustion, which has a lower nitrogen combustion effect.

[0063] Based on the multi-stage ammonia-doped reverse-injection swirl coal powder burner proposed in the above embodiment, the present invention also provides a method for using the multi-stage ammonia-doped reverse-injection swirl coal powder burner, comprising the following steps:

[0064] 1) Air is introduced from the secondary air guide tube, and passes through the cyclone in the secondary air channel to form a rotating airflow with tangential velocity and all enter the stable combustion chamber, and the rotating airflow and the outer tube of the transition channel work together to form a nested high-temperature flue gas reflux. The swirl number of the rotating airflow generated by the cyclone should be controlled between 1.0-2.0, and the wind speed of the secondary air should be controlled within the range of 25-45m / s.

[0065] 2) The air carrying coal powder is introduced from the primary air powder guide tube, and the primary ammonia enters the primary air powder guide tube through the primary ammonia pipeline and the primary ammonia nozzle at the inspection hole to form a mixture of primary air powder and primary ammonia. The input heat of the primary ammonia should be controlled within the range of 0-20% of the total input heat.

[0066] 3) The primary air powder and primary ammonia mixture enters the stable combustion chamber in reverse under the action of the reflux cap, and is preheated and ignites under the action of the high-temperature flue gas reflux to form a primary flame. After the reverse movement ends, it forms a main flame with the rotating airflow of the secondary air channel, and rotates and burns with it in the stable combustion chamber 8.

[0067] 4) The main flame of the swirling incineration forms a high-temperature flue gas reflux again at the outlet of the stable combustion chamber and behind the reflux cap. The secondary ammonia enters the high-temperature flue gas reflux through the secondary ammonia pipeline and the secondary ammonia nozzle. The input heat of the secondary ammonia should be controlled within the range of 0%-50% of the total input heat. The secondary ammonia is rapidly heated and cracked to form high-temperature combustibles for stable combustion with the main flame. The tertiary ammonia enters the nested high-temperature flue gas reflux through the tertiary ammonia pipeline and the tertiary ammonia nozzle, and is fully preheated and heated before being mixed into the main flame for combustion. And the input heat of the tertiary ammonia should be controlled within the range of 0%-30% of the total input heat.

[0068] When using the above method to adjust the ammonia blending ratio, it is first necessary to gradually reduce the original coal powder supply rate and reduce the coal powder concentration in the primary air-powder mixture. After a stable combustion process is formed, different ammonia blending mechanisms are selected to open according to the ammonia blending ratio requirements.

[0069] When the ammonia blending ratio is less than 20%, use the primary ammonia blending mechanism, the secondary ammonia blending mechanism or the tertiary ammonia blending mechanism alone;

[0070] When the ammonia blending ratio is 20%-60%, any two of the first-stage ammonia blending mechanism, the second-stage ammonia blending mechanism and the third-stage ammonia blending mechanism are turned on, or all three ammonia blending mechanisms are turned on at the same time;

[0071] When the ammonia mixing ratio is >60%, the first-stage ammonia mixing mechanism, the second-stage ammonia mixing mechanism and the third-stage ammonia mixing mechanism are opened at the same time.

[0072] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A multi-stage ammonia-blended reverse injection swirl burner, characterized in that: It comprises a primary ammonia mixing mechanism (1), a secondary ammonia mixing mechanism (2), a primary air powder guide tube (3), a tertiary ammonia mixing mechanism (4), a secondary air guide tube (5), a transition channel outer tube (6), a combustion stabilization chamber (8) and a reflux cap (9); The secondary air guide cylinder (5) and the combustion stabilization chamber (8) are connected to form a burner body, the transition channel outer cylinder (6) is arranged in the secondary air guide cylinder (5), and a secondary air channel is formed between the transition channel outer cylinder (6) and the secondary air guide cylinder (5); The primary air powder guide tube (3) is arranged through the burner body, the primary air powder guide tube (3) and the transition channel outer tube (6) form a closed transition channel, and the reflux cap (9) is arranged at the outlet end of the primary air powder guide tube (3); The first-stage ammonia blending mechanism (1) is arranged inside the primary air powder guide tube (3), the second-stage ammonia blending machine is arranged through the first-stage ammonia blending mechanism (1) and the reflux cap (9), and the third-stage ammonia blending mechanism (4) is arranged through the closed transition channel.

2. The multi-stage ammonia-blended reverse-injection swirl burner according to claim 1 is characterized in that: It also includes a cyclone (7) arranged in the secondary air channel.

3. The multi-stage ammonia-blended reverse-injection swirl burner according to claim 2 is characterized in that: An inspection hole (31) is provided at the elbow of the primary air powder guide tube (3), and the primary ammonia blending mechanism (1) is arranged along the inspection hole (31) in the primary air powder guide tube (3).

4. The multi-stage ammonia-blended reverse injection swirl burner according to claim 2, characterized in that: The primary ammonia mixing mechanism (1) comprises a primary ammonia mixing pipeline (11), the primary ammonia mixing pipeline (11) extends into the primary air powder guide cylinder (3), and the outlet end of the primary ammonia mixing pipeline (11) is provided with eight primary ammonia spray holes (12) evenly distributed along the circumferential direction.

5. The multi-stage ammonia-blended reverse injection swirl burner according to claim 4, characterized in that: The secondary ammonia blending mechanism (2) comprises a secondary ammonia blending pipeline (21), the secondary ammonia blending pipeline (21) is arranged inside the primary ammonia blending pipeline (11), and the secondary ammonia blending pipeline (21) has four secondary ammonia gas spray holes (22) evenly distributed in the circumferential direction.

6. The multi-stage ammonia-blended reverse-injection swirl burner according to claim 2, characterized in that: The three-stage ammonia blending mechanism (4) comprises a three-stage ammonia blending pipeline (41), and the three-stage ammonia blending pipeline (41) is connected to a plurality of three-stage ammonia blending branches (43). The plurality of three-stage ammonia blending branches (43) are all arranged in the closed transition channel, and the plurality of three-stage ammonia blending branches (43) are arranged around the inner circumference of the closed transition channel.

7. The multi-stage ammonia-blended reverse-injection swirl burner according to claim 6, characterized in that: A buffer coil (42) is connected between the tertiary ammonia-doping pipeline (41) and the plurality of tertiary ammonia-doping branches (43), and the axial direction of the buffer coil (42) is arranged along the axial direction of the outer tube (6) of the transition channel; the tertiary ammonia-doping pipeline (41) is vertically fixedly connected to the buffer coil (42), and the plurality of tertiary ammonia-doping branches (43) are circumferentially distributed on the buffer coil (42).

8. The multi-stage ammonia-blended reverse-injection swirl burner according to claim 7 is characterized in that: One end of the tertiary ammonia-doped branch (43) away from the buffer coil (42) extends into the combustion stabilization chamber (8), and a plurality of gas diffusion zones (44) are arranged at intervals along the flow direction of ammonia on the side wall of the tertiary ammonia-doped branch (43) extending into the combustion stabilization chamber (8), and each of the gas diffusion zones (44) includes a plurality of diffusion holes (441) arranged at intervals around the corresponding circumference of the tertiary ammonia-doped branch (43), and the diffusion holes (441) are arranged obliquely toward the combustion stabilization chamber (8), and the diameters of the diffusion holes (441) in the plurality of diffusion zones arranged in sequence at intervals along the flow direction of ammonia gradually decrease.

9. A method for using a multi-stage ammonia-doped reverse-jet swirl burner, comprising a multi-stage ammonia-doped reverse-jet swirl burner according to any one of claims 2 to 8, characterized in that: The following steps are involved: (1) Air is introduced from the secondary air guide tube, passes through the cyclone in the secondary air channel to form a rotating airflow with a tangential velocity and all enters the stable combustion chamber, and the rotating airflow and the outer tube of the transition channel work together to form a nested high-temperature flue gas reflow; The swirl number of the swirling airflow generated by the cyclone should be controlled between 1.0-2.0, and the wind speed of the secondary air should be controlled between 25-45m / s; (2) The air carrying coal powder is introduced from the primary air powder guide tube, and the primary ammonia enters the primary air powder guide tube through the primary ammonia mixing mechanism to form a mixture of primary air powder and primary ammonia. The input heat of the primary ammonia should be controlled within 0-20% of the total input heat. (3) The primary air powder and primary ammonia mixture enters the stable combustion chamber in reverse under the action of the reflux cap, and is preheated and ignites under the action of the high-temperature flue gas reflux to form a primary flame. After the reverse movement ends, it forms a main flame with the rotating airflow of the secondary air channel, and rotates and burns in the stable combustion chamber with it; (4) The main flame of the swirling incineration forms a high-temperature flue gas reflux again at the outlet of the stable combustion chamber and behind the reflux cap. The secondary ammonia enters the high-temperature flue gas reflux through the secondary ammonia mixing mechanism. The input heat of the secondary ammonia should be controlled within the range of 0%-50% of the total input heat. The secondary ammonia is rapidly heated and cracked to form high-temperature combustibles for stable combustion with the main flame; the tertiary ammonia enters the nested high-temperature flue gas reflux through the tertiary ammonia mixing mechanism, is fully preheated and heated, and then mixed into the main flame for combustion; and the input heat of the tertiary ammonia should be controlled within the range of 0%-30% of the total input heat.

10. The method of use according to claim 9, characterized in that: When adjusting the ammonia blending ratio, firstly, it is necessary to gradually reduce the original coal powder supply rate and reduce the coal powder concentration in the primary air-powder mixture. After a stable combustion process is formed, different ammonia blending mechanisms can be selected according to the ammonia blending ratio requirements: When the ammonia blending ratio is less than 20%, use the primary ammonia blending mechanism, the secondary ammonia blending mechanism or the tertiary ammonia blending mechanism alone; When the ammonia blending ratio is 20%-60%, any two of the first-stage ammonia blending mechanism, the second-stage ammonia blending mechanism and the third-stage ammonia blending mechanism are turned on, or all three ammonia blending mechanisms are turned on at the same time; When the ammonia mixing ratio is >60%, the first-stage ammonia mixing mechanism, the second-stage ammonia mixing mechanism and the third-stage ammonia mixing mechanism are opened at the same time.

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