An adjustable stable combustion ring structure swirl burner and its method of use

Abstract

The application discloses a swirl burner with adjustable stable combustion ring structure and a use method thereof, belongs to the technical field of burners and burner application, and aims at solving the problems of burner slagging and burning loss caused by burning Zhundong coal and the problem that the low-load stable combustion flexible peak regulation capacity cannot reach 20-30%. The swirl burner comprises, from outside to inside, an outer secondary air passage, an inner secondary air passage, a primary air passage and a central air passage. A plurality of tangential blades are arranged in the outer secondary air passage in a circumferential direction. An outer secondary air diffuser is arranged at the outlet of the outer secondary air passage. A plurality of axial adjustable blades are arranged in the inner secondary air passage in a circumferential direction. An inner secondary air diffuser is arranged at the outlet of the inner secondary air passage. A primary air diffuser is arranged at the outlet of the primary air passage. The adjustable stable combustion ring structure is further arranged at the outlet of the primary air passage. The application realizes flexible peak regulation of low-load operation stable combustion when the swirl burner burns Zhundong coal by changing the shape of the backflow area of the burner.

Description

Technical Field

[0001] This invention belongs to the field of burner and burner application technology, specifically relating to a swirl burner with an adjustable stabilizing ring structure and its usage method. Background Technology

[0002] The eastern part of the Junggar Basin in Xinjiang is rich in coal resources, among which the Zhundong Coalfield is the largest intact coalfield discovered in my country to date, with predicted coal reserves of 390 billion tons. Zhundong coal is characterized by high volatile matter content (Vdaf > 30%), low ignition point (400℃~460℃), low ash melting temperature (1080℃~1239℃), and large reserves, leading to its widespread use in China. Among the many coal-fired power plants, the opposed-flow pulverized coal boiler is a major type of boiler. Its burner is a swirl pulverized coal burner, employing a front and rear wall opposed-flow combustion method. By using swirling primary air or installing a central expanding cone to create a recirculation zone conducive to ignition, the high-temperature flue gas entrained in the recirculation zone ignites the pulverized coal gas flow, ensuring timely ignition. Therefore, the application of opposed-flow pulverized coal boilers in thermal power plants is becoming increasingly common. Because the ash melting temperature of Zhundong coal is 1080℃~1239℃, less than 1260℃, it is classified as a coal with a severe tendency to slagging. Furthermore, its high content of alkali metals and metal oxides easily leads to severe slagging problems in burners during actual combustion. Simultaneously, the low ignition point and easy ignition characteristics of Zhundong coal cause burners burning out easily, especially those equipped with stabilizing rings and primary air vents. In actual operation, severe burn-out of the stabilizing rings and primary air vents has been observed.

[0003] In recent years, the National Energy Administration's notice on carrying out the nationwide upgrading and transformation of coal-fired power units has pointed out the need to further improve the cleanliness, efficiency, and flexibility of coal-fired power units, and has put forward higher peak-shaving requirements. It requires some boilers to achieve stable combustion at 20%~30% or even lower loads, or even frequent start-ups and shutdowns, to promote the clean and low-carbon transformation of the power industry and help achieve the national carbon peak and carbon neutrality goals on schedule. Currently, when using Zhundong coal, the minimum stable combustion load of counter-current pulverized coal boilers can only reach 40% of the rated load, far below the peak-shaving requirement of stable combustion at 20%~30% or even lower loads.

[0004] To address the issues of burner slagging, burn-off, and insufficient flexible peak-shaving capacity under low load caused by burning Zhundong coal, this invention proposes a swirl burner device and method with an adjustable stabilizing ring structure. Summary of the Invention

[0005] In order to solve the problems of burner slagging and burn-off caused by burning Zhundong coal, and the problem that the low-load stable combustion and flexible peak-shaving capacity cannot reach 20-30%, this invention proposes a swirl burner with an adjustable stable combustion ring structure and its usage method.

[0006] A swirl burner with an adjustable stabilizing ring structure is provided. The swirl burner is provided with an outer secondary air channel, an inner secondary air channel, a primary air channel and a central air channel from the outside to the inside. Multiple tangential blades are arranged circumferentially inside the outer secondary air channel, and each tangential blade is equidistantly mounted on an annular plate inside the outer secondary air channel to form a tangential impeller. An outer secondary air flare is installed at the outlet of the outer secondary air channel. Multiple axially adjustable blades are arranged circumferentially inside the inner secondary air channel, and each axially adjustable blade is mounted on a sleeve on the outer wall of the inner secondary air channel to form an axially movable impeller. An inner secondary air flare is installed at the outlet of the inner secondary air channel, and a primary air flare is installed at the outlet of the primary air channel. The characteristic feature is that an adjustable stabilizing ring structure is also installed at the outlet of the primary air channel.

[0007] Furthermore, the adjustable flame-stabilizing ring structure includes a transmission mechanism support plate, a rotating handwheel, a gear baffle, a chain, n rotating shafts, n flame-stabilizing blocks, n transmission rods, n gears, n driving bevel gears, and n driven bevel gears. The transmission mechanism support plate is disposed in the primary air duct, and its outer circular wall is fixedly connected to the inner ring wall of the primary air duct. A connecting sleeve is provided at one end of the transmission mechanism support plate near the air outlet, and one end of the connecting sleeve is fixedly connected to the end of the transmission mechanism support plate near the air outlet. The sleeve and the transmission mechanism support plate are coaxially arranged. A gap is provided between the outer surface of the sleeve and the inner annular wall of the primary air duct. n transmission rods are equidistantly inserted along the circumference of the transmission mechanism support plate at the end of the support plate furthest from the air outlet. Each transmission rod is rotatably connected to the support plate via a bearing. One end of each transmission rod passes through the support plate and is positioned in the gap between the sleeve and the inner annular wall of the primary air duct. The other end of each transmission rod remains outside the support plate at the end furthest from the air outlet. A driving bevel gear is fitted on one end of the rod. n rotating shafts are equidistantly inserted on the outer circular surface of the connecting sleeve along the circumference, and the axis of each rotating shaft is perpendicular to the axis of the connecting sleeve. Each rotating shaft is rotatably connected to the connecting sleeve through a bearing. One end of each rotating shaft extends into the gap between the connecting sleeve and the inner ring wall of the primary air duct, and a driven bevel gear is fitted on one end of each rotating shaft. Each driven bevel gear is meshed with a corresponding driving bevel gear. The other end of each rotating shaft extends into the connecting sleeve, and a flame stabilizing block is installed on the other end of each rotating shaft. A gear baffle is set at the end of the transmission mechanism support plate away from the air outlet, and the gear baffle is fitted on n transmission rods. The gear baffle is clearance-fitted with each transmission rod. The gear baffle is detachably connected to the inner ring wall of the primary air duct. Each gear is fitted on a corresponding transmission rod. A chain is fitted on n gears, and the n gears are connected by chain transmission. A rotating handwheel is set at the end of the gear baffle near the air outlet, and the rotating handwheel is installed on the other end of a transmission rod.

[0008] Furthermore, the inner diameter of the primary air duct outlet is R, the adjustable stabilizing ring is composed of n stabilizing blocks, the value of n is in the range of 6-16, the height of each stabilizing ring is h1=7%~8%R, the height of the transmission mechanism support plate is h2=3.5%~4%R, and the length of the rotating shaft is h3=1.4~1.8h2.

[0009] Furthermore, the adjustable flame-stabilizing ring structure includes a transmission mechanism support plate, a rotating handwheel, a gear baffle, a chain, n rotating shafts, n flame-stabilizing blocks, n transmission rods, n gears, n worm gears, and n worm sleeves. The transmission mechanism support plate is disposed in the primary air duct, and its outer circular wall is fixedly connected to the inner ring wall of the primary air duct. The n transmission rods are equidistantly inserted along the circumference of the transmission mechanism support plate at the end of the transmission mechanism support plate away from the air outlet. Each transmission rod is rotatably connected to the transmission mechanism support plate via a bearing. One end of each transmission rod passes through the transmission mechanism support plate and is disposed inside the transmission mechanism support plate near the air outlet, while the other end of each transmission rod remains outside the transmission mechanism support plate at the end away from the air outlet. A worm gear is fitted onto one end of each transmission rod. The n rotating shafts are equidistantly disposed along the circumference of the transmission mechanism support plate at the end near the air outlet. Each rotating shaft is arranged tangentially along the inner diameter of the primary air duct. A worm gear sleeve is fitted in the middle of each rotating shaft. Each rotating shaft is connected to a corresponding worm gear through the worm gear sleeve. Each rotating shaft is fixedly connected to the end of the transmission mechanism support plate near the air outlet through a set of connecting ears. The rotating shaft and the connecting ears are rotatably connected through bearings. Each flame stabilizer block is installed on the outer circumference of a rotating shaft. A gear baffle is set at the end of the transmission mechanism support plate away from the air outlet. The gear baffle is fitted on n transmission rods. The gear baffle is clearance-fitted with each transmission rod. The gear baffle is detachably connected to the inner ring wall of the primary air duct. Each gear is fitted on a corresponding transmission rod. A chain is fitted on n gears. The n gears are connected through chain transmission. A rotating handwheel is set at the end of the gear baffle near the air outlet. The rotating handwheel is installed on the other end of a transmission rod.

[0010] Furthermore, the inner diameter of the primary air duct outlet is R, the adjustable stabilizing ring is composed of n stabilizing blocks, the value of n is in the range of 6-16, the height of each stabilizing ring is h1=6.3%~8.7%R, the height of the transmission mechanism support plate is h2=3.5%~4%R, and the length of the rotating shaft is h3=7.2~8.1h2;

[0011] A method for using a swirl burner with an adjustable stabilizing ring structure, the specific steps of which are as follows:

[0012] First, the swirl pulverized coal burner is installed on the front and rear walls of the swirl pulverized coal boiler. The installation method is a counter-flow arrangement. An adjustable stabilizing ring structure is installed at the burner nozzle. By turning the handwheel, the included angle β1 between the stabilizing ring and the primary air channel outlet plane is adjusted, thereby adjusting the shielding area of ​​the stabilizing ring and the primary air outlet velocity, so as to adjust the shape and size of the recirculation zone at the burner outlet.

[0013] The primary air outlet velocity ranges from 22 to 25 m / s. When β1 = 0°, that is, when the flame stabilizer block does not rotate, its shielding area is 40%, which is the ratio of the wind shielding area of the flame stabilizer ring to the cross-sectional area of the primary air passage. After adjusting the angle β1 between the flame stabilizer ring and the outlet plane of the primary air passage by rotating the handwheel, the primary air outlet velocity ranges from 20 to 28 m / s. The number of flame stabilizer blocks contained in the flame stabilizer ring is arranged as n, which can better adapt to swirl burners of different scales;

[0014] When the boiler operates under the condition of 20 - 30% of the rated load, this is a low-load operation, and a relatively large central recirculation zone is required at the outlet of the swirl burner; The operation is as follows: Rotate the handwheel to make the flame stabilizer ring rotate through the transmission mechanism, and adjust the angle β1 between the flame stabilizer ring and the outlet plane of the primary air passage to 60° - 90°. After the above operation, the shielding area is 0 - 15%, and the primary air outlet velocity ranges from 20 to 23 m / s. A relatively large and stable central recirculation zone can be formed at the outlet of the swirl burner. At this time, the distance between the starting point of the central recirculation zone and the burner outlet is 0.15 < a < 0.2d, the length is 1.5d < l < 1.8d, and the diameter is 0.5d < D1 < 0.8d, where d is the diameter of the outer secondary air flare;

[0015] When the boiler operates under the condition of 30 - 50% of the rated load, this is a medium-load operation, and a relatively large central recirculation zone is still required at the outlet of the swirl burner; The operation is as follows: Rotate the handwheel to make the flame stabilizer ring rotate through the transmission mechanism, and adjust the angle β1 between the flame stabilizer ring and the outlet plane of the primary air passage to 35° - 60°. After the above operation, the shielding area is 15% - 30%, and the primary air outlet velocity ranges from 23 to 26 m / s. At this time, the distance between the starting point of the central recirculation zone and the burner outlet is 0.2d < a < 0.25d, the length is 1.0d < l < 1.5d, and the diameter is 0.45d < D1 < 0.5d, where d is the diameter of the outer secondary air flare;

[0016] When the boiler operates under the condition of more than 50% of the rated load, this is a high-load operation, and an annular recirculation zone is required at the outlet of the swirl burner; The operation is as follows: Rotate the handwheel to make the flame stabilizer ring rotate through the transmission mechanism, and adjust the angle β1 between the flame stabilizer ring and the outlet plane of the primary air passage to 0° - 35°. After the above operation, the shielding area is 30% - 40%, and the primary air outlet velocity ranges from 26 to 28 m / s. The pulverized coal is entrained by the high-temperature flue gas in the annular recirculation zone and ignited, and the combustion is maintained. The distance between the starting point of the annular recirculation zone and the burner outlet is a > 0.25d, the length is 0.6d < l < 1.0d, and the diameter is 0.2d < D2 < 0.4d, where d is the diameter of the outer secondary air flare;

[0017] A method for using a swirl burner with an adjustable flame stabilizer ring structure, the specific steps of the method are as follows:

[0018] First, install the swirl pulverized coal burner on the front and rear walls of the swirl pulverized coal boiler. The installation method adopted is opposed arrangement. An adjustable flame stabilization ring structure is installed at the burner nozzle. By rotating the handwheel, the angle β2 between the flame stabilization ring and the outlet plane of the primary air passage is adjusted, thereby adjusting the shielding area of the flame stabilization ring and the primary air outlet velocity, so as to achieve the purpose of adjusting the shape and size of the recirculation zone at the burner outlet;

[0019] The primary air outlet velocity ranges from 22 to 25 m / s. When β2 = 0°, that is, when the flame stabilization block has no rotation, its shielding area is 40%, which is the ratio of the wind shielding area of the flame stabilization ring to the cross-sectional area of the primary air passage. After adjusting the angle β2 between the flame stabilization ring and the outlet plane of the primary air passage by rotating the handwheel, the primary air outlet velocity ranges from 20 to 28 m / s. The number of flame stabilization blocks included in the flame stabilization ring is arranged as n, which can better adapt to swirl burners of different scales;

[0020] When the boiler operates under the condition of 20 - 30% of the rated load, this is a low-load operation, and a relatively large central recirculation zone is required at the outlet of the swirl burner; the operation is as follows: Rotate the handwheel to make the flame stabilization ring rotate through the transmission mechanism, and adjust the angle β2 formed by the flame stabilization ring and the outlet plane of the primary air passage to 65° - 90°. After the above operation, the shielding area is 0 - 15%, and the primary air outlet velocity ranges from 20 to 23 m / s. A relatively large and stable central recirculation zone can be formed at the outlet of the swirl burner. At this time, the distance between the starting point of the central recirculation zone and the burner outlet is 0.15 < a < 0.18d, the length is 1.6d < l < 1.9d, and the diameter is 0.5d < D1 < 0.9d, where d is the diameter of the outer secondary air flare;

[0021] When the boiler operates under the condition of 30 - 50% of the rated load, this is a medium-load operation, and a relatively large central recirculation zone is still required at the outlet of the swirl burner; the operation is as follows: Rotate the handwheel to make the flame stabilization ring rotate through the transmission mechanism, and adjust the angle β2 formed by the flame stabilization ring and the outlet plane of the primary air passage to 30° - 65°. After the above operation, the shielding area is 15% - 30%, and the primary air outlet velocity ranges from 23 to 26 m / s. At this time, the distance between the starting point of the central recirculation zone and the burner outlet is 0.18d < a < 0.21d, the length is 1.2d < l < 1.6d, and the diameter is 0.4d < D1 < 0.5d, where d is the diameter of the outer secondary air flare;

[0022] When the boiler operates at a load above 50% of the rated load, this is a high-load operation, and an annular recirculation zone is required at the outlet of the tangential firing burner; the operation is as follows: by rotating the handwheel through the transmission mechanism, the stable combustion ring rotates, and the angle β2 formed between the stable combustion ring and the outlet plane of the primary air passage is adjusted to 0° to 30°. After the above operation, the shielding area is 30% to 40%, the primary air outlet velocity range is 26 to 28 m / s, the pulverized coal is entrained by the high-temperature flue gas in the annular recirculation zone and ignited, and the combustion is maintained. The distance a between the starting position of the annular recirculation zone and the burner outlet is a > 0.21d, the length is 0.7d < l < 1.2d, and the diameter is 0.12d < D2 < 0.4d, where d is the diameter of the outer secondary air flare.

[0023] The beneficial effects of this application compared with the prior art:

[0024] A tangential firing burner device with an adjustable stable combustion ring structure and its usage method provided by the present invention can flexibly adjust the shape and size of the recirculation zone at the burner outlet according to the boiler load, meet the requirements of flexible peak regulation, achieve stable combustion, and avoid burning and slagging of the burner nozzle at the same time.

[0025] Most of the prior arts set a fixed and unchangeable stable combustion ring device at the primary air outlet of the burner. With a fixed shielding area, the shape and size of the recirculation zone formed at the burner outlet are both fixed, which fails to meet the requirements of flexible peak shaving, is not conducive to the stable combustion of the boiler, and may also cause problems such as burning damage and slagging of the burner nozzle. When a fixed and unchangeable stable combustion ring device with a shielding area of 40% - 45%, or even larger, is installed at the primary air outlet of the burner, the size of the recirculation zone formed at the burner nozzle is relatively small (diameter 0.2d - 0.3d, length 0.5d - 0.7d), and the starting position of the recirculation zone is relatively close to the burner nozzle (0 < a < 0.1d). For the high-load operation of the boiler, the size of the recirculation zone is small, the amount of high-temperature flue gas entrained by the recirculation is less, and the pulverized coal ignites late, ensuring that the burner nozzle is not damaged during high-load operation. However, when the boiler is operating at medium and low loads, the size of the recirculation zone is small at this time, and the amount of high-temperature flue gas entrained by the recirculation is less, resulting in a lower temperature in the main combustion zone during medium and low loads, untimely ignition of the pulverized coal, easy slagging of the burner nozzle, and inability to ensure the stable combustion performance of the boiler at medium and low loads. The lowest stable combustion load can only reach 40% of the rated load, failing to meet the flexible peak shaving requirements of stable combustion at 20% - 30% or even lower loads. When a fixed and unchangeable stable combustion ring device with a shielding area of 10% - 25%, or even smaller, is installed at the primary air outlet of the burner, the size of the recirculation zone formed at the burner nozzle is relatively large (diameter 0.7d - 1.3d, length 1.7d - 2.1d), and the starting position of the recirculation zone is still relatively close to the burner nozzle (0 < a < 0.15d). For the medium and low-load operation of the boiler, the size of the recirculation zone is large, the amount of high-temperature flue gas entrained by the recirculation is more, the temperature in the main combustion zone increases, and the pulverized coal ignites in a timely manner, ensuring the stable combustion performance of the boiler during medium and low-load operation. However, when the boiler is operating at high loads, the size of the recirculation zone is large, the amount of high-temperature flue gas entrained by the recirculation is more, resulting in an excessive temperature in the main combustion zone during high loads, premature combustion of the pulverized coal, and problems such as burning damage and slagging of the burner nozzle during long-term operation of the boiler, posing a safety hazard to the long-term operation of the boiler. Therefore, for a fixed and unchangeable stable combustion ring device, it is impossible to ensure the stable combustion ability during medium and low-load operation while solving the problems of burning damage and slagging of the burner nozzle during high-load operation of the boiler, failing to meet the requirements of flexible peak shaving.

[0026] In the present invention, a swirl burner with an adjustable stable combustion ring structure and its usage method. The stable combustion ring device installed at the primary air outlet of the burner is adjustable. By rotating the handwheel through the transmission mechanism, the angle between the stable combustion ring and the outlet plane of the primary air passage is adjusted, and the shielding area of the stable combustion ring is adjusted, so as to achieve the purpose of adjusting the shape and size of the recirculation zone at the burner outlet.

[0027] When the boiler is operating at high load (above 50% of rated load), the flue gas temperature in the main combustion zone is high. The high-temperature flue gas recirculated and sucked in can easily cause burn-off to the burner nozzles, and prolonged operation can also cause nozzle slagging. Therefore, the small annular recirculation zone formed at the burner nozzle can be utilized. The angle between the stabilizing ring and the primary air duct outlet plane can be adjusted by turning the handwheel. Figure 3 The structure shown allows for adjusting the included angle β1 from 0° to 35°, and the stabilizing ring's shielding area to 30% to 40%. In this case, the length of the recirculation zone can be stabilized within the range of 0.6d to 1.0d, and the diameter within the range of 0.2d to 0.4d. The distance between the starting point of the recirculation zone and the burner outlet is adjusted to a > 0.25d. Figure 6 The structure shown allows for adjusting the included angle β2 from 0° to 30°, stabilizing the length of the recirculation zone within the range of 0.7d to 1.2d and the diameter within the range of 0.2d to 0.4d. Adjusting the distance between the starting point of the recirculation zone and the burner outlet to a > 0.21d reduces the size of the recirculation zone compared to a fixed-circulation ring device, thus reducing the amount of high-temperature flue gas entrained in the recirculation zone and preventing burner nozzle burn-out. Conversely, increasing the size of the recirculation zone compared to a fixed-circulation ring device ensures increased high-temperature flue gas entrainment at low and medium loads, guaranteeing stable boiler combustion. The increased distance between the starting point of the recirculation zone and the burner outlet compared to a fixed-circulation ring device further enhances this stability, preventing burner nozzle burn-out and slagging while ensuring stable boiler combustion and achieving flexible peak-shaving.

[0028] When the boiler is operating at medium load (30-50% of rated load), the flue gas temperature in the main combustion zone is lower than at high load. Therefore, the size of the recirculation zone needs to be increased to utilize the central recirculation zone generated by the burner nozzles to entrain more high-temperature flue gas, ensuring timely combustion of pulverized coal and guaranteeing stable combustion. The adjustment method is the same as described above. Figure 3 The structure shown, with an adjustable included angle β1 of 35°~60° and a stabilizing ring shielding area of ​​15%~30%, can stabilize the length of the recirculation zone within the range of 1.0d~1.5d and the diameter within the range of 0.4d~0.5d. The distance between the starting point of the recirculation zone and the burner outlet can be adjusted to 0.2d~0.25d. Figure 6The structure shown allows for adjusting the included angle β2 to 30°~65° and the stabilizing ring's shielding area to 15%~30%. This stabilizes the length of the recirculation zone within the range of 1.2d~1.6d and the diameter within the range of 0.4d~0.5d. Adjusting the distance between the recirculation zone's starting point and the burner outlet to 0.18d~0.21d results in a larger recirculation zone size compared to a fixed-ring stabilizing device. This allows the recirculation zone to entrain more high-temperature flue gas, ensuring timely ignition and stable combustion of the pulverized coal. Conversely, a smaller recirculation zone size compared to a fixed-ring stabilizing device reduces the amount of high-temperature flue gas entrained during high-load operation, preventing burner nozzle burn-out. At this point, the distance between the recirculation zone's starting point and the burner outlet is still increased compared to a fixed-ring stabilizing device, simultaneously achieving stable combustion and preventing burner nozzle burn-out and slagging.

[0029] When the boiler is operating at low load (20-30% of rated load), the flue gas temperature in the main combustion zone is lower, requiring a larger recirculation zone to entrain more high-temperature flue gas and ensure stable combustion of pulverized coal. The adjustment method is the same as described above. Figure 3 The structure shown allows for adjusting the included angle β1 to 60°~90° and the stabilizing ring shielding area to 0%~15%. This stabilizes the length of the recirculation zone within the range of 1.5d~1.8d and the diameter within the range of 0.5d~0.8d. Adjusting the distance between the starting point of the recirculation zone and the burner outlet to 0.15d~0.2d provides a suitable solution. Figure 6 The structure shown allows for adjusting the included angle β2 to 65°~90° and the stabilizing ring shielding area to 0%~15%. This stabilizes the length of the recirculation zone within the range of 1.6d~1.9d and the diameter within the range of 0.5d~0.9d. Adjusting the distance between the starting point of the recirculation zone and the burner outlet to 0.15d~0.18d results in a larger recirculation zone size compared to a fixed stabilizing ring device, and a reasonable increase compared to medium load conditions. This allows the recirculation zone to entrain more high-temperature flue gas, ensuring timely ignition and stable combustion of pulverized coal. Conversely, a smaller recirculation zone size compared to a fixed stabilizing ring device reduces the amount of high-temperature flue gas entrained during high load operation, thus preventing burner nozzle burnout. Even with this adjustment, the distance between the starting point of the recirculation zone and the burner outlet is still larger than with a fixed stabilizing ring device, resolving the problem of burner nozzle slagging.

[0030] To adjust the angle between the combustion stabilizing ring and the primary air duct outlet plane under different boiler loads, the shape and size of the recirculation zone at the burner outlet can be adjusted to better adapt to the combustion of pulverized coal under different loads. This ensures stable combustion while preventing burnout and slagging at the burner nozzle, thus achieving the goal of flexible peak shaving. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the arrangement of the swirl burner with the adjustable stabilizing ring structure described in this application;

[0032] Figure 2 This is a schematic diagram of the swirl burner with the adjustable stabilizing ring structure described in this application;

[0033] Figure 3 This is a schematic diagram of the arrangement of the adjustable combustion stabilizing ring structure in this application (the rotating shaft is arranged radially along the inner diameter of the primary air channel).

[0034] Figure 4 This is a schematic diagram of the connection of the adjustable end of the adjustable combustion ring structure in this application (the rotating shaft is arranged radially along the inner diameter of the primary air channel).

[0035] Figure 5 This is a schematic diagram of the transmission of the stabilizing block in the adjustable stabilizing ring structure of this application (the rotating shaft is arranged radially along the inner diameter of the primary air channel).

[0036] Figure 6 This is a schematic diagram of the rotation angle β1 of a single flame stabilizing ring in the adjustable flame stabilizing ring structure of this application (the rotation axis is arranged radially along the inner diameter of the primary air channel).

[0037] Figure 7 This is a schematic cross-section of the adjustable flame-stabilizing ring structure in this application (the rotation axis is arranged radially along the inner diameter of the primary air channel).

[0038] Figure 8 This is a schematic diagram of the arrangement of the adjustable flame stabilizing ring structure in this application (the rotating shaft is arranged in the tangential direction of the radial direction of the inner diameter of the primary air channel).

[0039] Figure 9 This is a schematic diagram of a single flame stabilizing ring in the adjustable flame stabilizing ring structure of this application (the rotation axis is arranged in the tangential direction of the radial direction of the inner diameter of the primary air channel).

[0040] Figure 10 The connection diagram of the adjustable end of the adjustable flame stabilizing ring structure in this application (the rotating shaft is arranged in the tangential direction of the radial direction of the inner diameter of the primary air channel);

[0041] Figure 11 This is a schematic diagram of the transmission of the stabilizing block in the adjustable stabilizing ring structure of this application (the rotating shaft is arranged in the tangential direction of the radial direction of the inner diameter of the primary air channel).

[0042] Figure 12 This is a schematic diagram of the rotation angle β2 of a single flame stabilizing ring in the adjustable flame stabilizing ring structure of this application (the rotation axis is arranged in the tangential direction of the radial direction of the inner diameter of the primary air channel).

[0043] Figure 13This is a schematic cross-sectional view of the adjustable flame-stabilizing ring structure in this application (the rotation axis is arranged in the tangential direction of the radial direction of the inner diameter of the primary air channel).

[0044] Figure 14 This is a schematic diagram showing the shape and size of the outlet recirculation zone (annular recirculation zone) of the swirl burner in this application.

[0045] Figure 15 This is a schematic diagram showing the shape and size of the outlet recirculation zone (central recirculation zone) of the swirl burner in this application.

[0046] In the diagram: 1. Swirl pulverized coal boiler, 2. Swirl pulverized coal burner, 3. Front wall, 4. Rear wall, 5. External secondary air duct, 6. Internal secondary air duct, 7. Primary air duct, 8. Central air duct, 9. External secondary air vent, 10. Internal secondary air vent, 11. Primary air vent, 12. Adjustable combustion stabilizing ring structure, 13. Tangential blade, 14. Axially adjustable blade, 15. Transmission mechanism support plate, 16. Rotating shaft, 17. Combustion stabilizing block, 18. Rotating handwheel, 19. Transmission rod, 20. Gear baffle, 21. Gear, 22. Chain, 23. Driving bevel gear, 24. Driven bevel gear, 25. Worm gear, and 26. Worm sleeve. Detailed Implementation

[0047] Specific implementation method one: Combining Figures 1 to 15 This embodiment describes a swirl burner with an adjustable stabilizing ring structure. The swirl burner is provided with an outer secondary air channel 5, an inner secondary air channel 6, a primary air channel 7, and a central air channel 8, arranged sequentially from the outside to the inside. Multiple tangential blades 13 are arranged circumferentially within the outer secondary air channel 5, and each tangential blade 13 is equidistantly mounted on an annular plate within the outer secondary air channel 5, forming a tangential impeller. An outer secondary air flare 9 is installed at the outlet of the outer secondary air channel 5. Multiple axially adjustable blades 14 are arranged circumferentially within the inner secondary air channel 6, and each axially adjustable blade 14 is mounted on a sleeve on the outer wall of the inner secondary air channel 6, forming an axially movable impeller. An inner secondary air flare 10 is installed at the outlet of the inner secondary air channel 6, and a primary air flare 11 is installed at the outlet of the primary air channel 7. The characteristic feature is that an adjustable stabilizing ring structure 12 is also installed at the outlet of the primary air channel 7.

[0048] Specific Implementation Method Two: Combining Figures 1 to 15This embodiment differs from specific embodiment one in that the adjustable flame-stabilizing ring structure 12 includes a transmission mechanism support plate 15, a rotating handwheel 18, a gear baffle 20, a chain 22, n rotating shafts 16, n flame-stabilizing blocks 17, n transmission rods 19, n gears 21, n driving bevel gears 23, and n driven bevel gears 24. The transmission mechanism support plate 15 is disposed in the primary air channel 7, and the outer circular wall of the transmission mechanism support plate 15 is fixedly connected to the inner ring wall of the primary air channel 7. A connecting sleeve is provided at one end of the transmission mechanism support plate 15 near the air outlet, and one end of the connecting sleeve is connected to the transmission mechanism support plate 15. The end of the support plate 15 near the air outlet is fixedly connected, and the connecting sleeve is coaxially arranged with the transmission mechanism support plate 15. A gap is provided between the outer circular surface of the connecting sleeve and the inner ring wall of the primary air channel 7. n transmission rods 19 are equidistantly inserted along the circumference of the transmission mechanism support plate 15 at the end of the transmission mechanism support plate 15 away from the air outlet, and each transmission rod 19 is rotatably connected to the transmission mechanism support plate 15 through a bearing. One end of each transmission rod 19 passes through the transmission mechanism support plate 15 and is located in the gap between the connecting sleeve and the inner ring wall of the primary air channel 7, while the other end of each transmission rod 19 remains at the end of the transmission mechanism support plate 15 away from the air outlet. Externally, a driving bevel gear 23 is fitted onto one end of each transmission rod 19. n rotating shafts 16 are equidistantly inserted circumferentially onto the outer surface of the connecting sleeve, with the axis of each rotating shaft 16 perpendicular to the axis of the connecting sleeve. Each rotating shaft 16 is rotatably connected to the connecting sleeve via a bearing. One end of each rotating shaft 16 extends into the gap between the connecting sleeve and the inner annular wall of the primary air duct 7, and a driven bevel gear 24 is fitted onto one end of each rotating shaft 16. Each driven bevel gear 24 meshes with a corresponding driving bevel gear 23 for transmission. The other end of each rotating shaft 16 extends into the connecting sleeve, and each… A flame stabilizing block 17 is installed on the other end of the rotating shaft 16. A gear baffle 20 is located at the end of the transmission mechanism support plate 15 away from the air outlet, and the gear baffle 20 is sleeved on n transmission rods 19. The gear baffle 20 is clearance-fitted with each transmission rod 19. The gear baffle 20 is detachably connected to the inner ring wall of the primary air duct 7. Each gear 21 is correspondingly sleeved on one transmission rod 19. A chain 22 is sleeved on the n gears 21, and the n gears 21 are connected by the chain 22. A rotating handwheel 18 is located at the end of the gear baffle 20 near the air outlet, and the rotating handwheel 18 is installed on the other end of one transmission rod 19. Other components and connection methods are the same as in specific embodiment one.

[0049] Specific implementation method three: Combining Figures 1 to 15Regarding this embodiment, the difference between this embodiment and the second specific embodiment is that the inner diameter of the outlet of the primary air passage 7 is R, the adjustable flame-stabilizing ring is composed of n flame-stabilizing blocks 17, the value range of n is 6 - 16, the height of each flame-stabilizing ring is h1 = 7% - 8%R, the height of the driving mechanism support plate 15 is h2 = 3.5% - 4%R, and the length of the rotating shaft 16 is h3 = 1.4 - 1.8h2. Other compositions and connection methods are the same as those in the second specific embodiment.

[0050] Combined with the second to the third specific embodiments, according to the change of the boiler load, by rotating the handwheel 18 to change the included angle β1 between the flame-stabilizing ring and the outlet plane of the primary air passage 7, adjusting its wind-blocking area and the swirl intensity of the primary air flow, and regulating the shape and size of the recirculation zone at the burner outlet. When the boiler operates under low load conditions (20 - 30% of the rated load), 60° < β1 < 90°, the blocking area is 0 - 15%, and the utilized recirculation zone is adjusted to a larger and more stable central recirculation zone. The distance between the starting position of the recirculation zone and the burner outlet is 0.15 < a < 0.2d, the length of the recirculation zone is 1.5d < l < 1.8d, and the diameter is 0.5d < D1 < 0.8d (d is the diameter of the outer secondary air flare). When the boiler operates under medium load conditions (30 - 50% of the rated load), 35° < β1 < 60°, the blocking area is 15% - 30%, and the utilized recirculation zone is still the central recirculation zone, but its size becomes smaller compared to the low load. The distance between the starting position of the recirculation zone and the burner outlet is 0.2d < a < 0.25d, the length of the recirculation zone is 1.0d < l < 1.5d, and the diameter is 0.4d < D1 < 0.5d; when the boiler operates under high load conditions (above 50% of the rated load), 0° < β1 < 35°, the blocking area is 30% - 40%, and the utilized recirculation zone is adjusted from the central recirculation zone to an annular recirculation zone. The distance between the starting position of the recirculation zone and the burner outlet is a > 0.25d, the length of the recirculation zone is 0.6d < l < 1.0d, and the diameter is 0.2d < D2 < 0.4d.

[0051] Specific embodiment four: Combined with Figures 1 to 15This embodiment differs from specific embodiment one in that the adjustable flame-stabilizing ring structure 12 includes a transmission mechanism support plate 15, a rotating handwheel 18, a gear baffle 20, a chain 22, n rotating shafts 16, n flame-stabilizing blocks 17, n transmission rods 19, n gears 21, n worm gears 25, and n worm sleeves 26. The transmission mechanism support plate 15 is disposed in the primary air channel 7, and the outer circular wall of the transmission mechanism support plate 15 is fixedly connected to the inner ring wall of the primary air channel 7. The n transmission rods 19 are arranged along the transmission mechanism. The support plate 15 is circumferentially and equidistantly inserted on the end of the transmission mechanism support plate 15 away from the air outlet. Each transmission rod 19 is rotatably connected to the transmission mechanism support plate 15 via a bearing. One end of each transmission rod 19 passes through the transmission mechanism support plate 15 and is located inside the transmission mechanism support plate 15 near the air outlet. The other end of each transmission rod 19 remains outside the transmission mechanism support plate 15 away from the air outlet. A worm gear 25 is fitted onto one end of each transmission rod 19. n rotating shafts 16 are circumferentially and equidistantly arranged on the transmission mechanism support plate. 15 is located near the air outlet end, and each rotating shaft 16 is arranged tangentially along the inner diameter of the primary air duct 7. A worm gear sleeve 26 is fitted into the middle of each rotating shaft 16, and each rotating shaft 16 is connected to a corresponding worm wheel 25 via the worm gear sleeve 26. Each rotating shaft 16 is fixedly connected to the end of the transmission mechanism support plate 15 near the air outlet via a set of connecting ears, and the rotating shaft 16 and the connecting ears are rotatably connected via bearings. Each flame stabilizer block 17 is correspondingly installed on the outer circumferential surface of a rotating shaft 16. A gear baffle 20 is provided. At the end of the transmission mechanism support plate 15 furthest from the air outlet, a gear baffle 20 is fitted onto n transmission rods 19, with the gear baffle 20 and each transmission rod 19 in clearance fit. The gear baffle 20 is detachably connected to the inner ring wall of the primary air duct 7. Each gear 21 is fitted onto one transmission rod 19, and a chain 22 is fitted onto the n gears 21, which are connected by the chain 22. A rotating handwheel 18 is located at the end of the gear baffle 20 near the air outlet and is mounted on the other end of one transmission rod 19. Other components and connections are the same as in Specific Embodiment 1.

[0052] Specific Implementation Method Five: Combining Figures 1 to 15 This embodiment differs from Specific Embodiment Four in that: the inner diameter of the primary air duct 7 outlet is R; the adjustable combustion stabilizing ring is composed of n combustion stabilizing blocks 17, where n ranges from 6 to 16; the height of each combustion stabilizing ring is h1 = 6.3%~8.7%R; the height of the transmission mechanism support plate 15 is h2 = 3.5%~4%R; and the length of the rotating shaft 16 is h3 = 7.2~8.1h2. Other components and connections are the same as in Specific Embodiment Four.

[0053] As described in Embodiment 4 and Embodiment 5, according to the change of boiler load, by rotating the handwheel 18, the included angle β2 between the stable combustion ring and the outlet plane of the primary air passage 7 is changed to adjust its wind blocking area and the swirl intensity of the primary air flow, and the shape and size of the recirculation zone at the burner outlet are regulated. When the boiler operates under low load conditions (20 - 30% of the rated load), 65° < β2 < 90°, the blocking area is 0 - 15%, and the utilized recirculation zone is adjusted to a central recirculation zone with a larger and more stable size. The distance between the starting position of the recirculation zone and the burner outlet is 0.15 < a < 0.18d, the length of the recirculation zone is 1.6d < l < 1.9d, and the diameter is 0.5d < D1 < 0.9d. When the boiler operates under medium load conditions (30 - 50% of the rated load), 30° < β2 < 65°, the blocking area is 15% - 30%, and the combustion still utilizes the central recirculation zone, but its size becomes smaller compared to the low load. The distance between the starting position of the recirculation zone and the burner outlet is 0.18d < a < 0.21d, the length of the recirculation zone is 1.2d < l < 1.6d, and the diameter is 0.4d < D1 < 0.5d. When the boiler operates under high load conditions (above 50% of the rated load), 0° < β2 < 30°, the blocking area is 30% - 40%, and the recirculation zone utilized for combustion is adjusted from the central recirculation zone to an annular recirculation zone. The distance between the starting position of the recirculation zone and the burner outlet is a > 0.21d, the length of the recirculation zone is 0.7d < l < 1.2d, and the diameter is 0.2d < D2 < 0.4d.

[0054] Embodiment 6: Combining Figures 1 to 15 to illustrate this embodiment, this embodiment provides a method for using a swirl burner with an adjustable stable combustion ring structure. The specific steps of the method are as follows:

[0055] First, install the swirl pulverized coal burner 2 on the front wall 3 and the rear wall 4 of the swirl pulverized coal boiler 1. The installation method is opposed arrangement. An adjustable stable combustion ring structure 12 is installed at the burner nozzle. By rotating the handwheel 18, the included angle β1 between the stable combustion ring and the outlet plane of the primary air passage 7 is adjusted, thereby adjusting the blocking area of the stable combustion ring and the primary air outlet velocity, so as to achieve the purpose of adjusting the shape and size of the recirculation zone at the burner outlet;

[0056] The range of the primary air outlet velocity is 22 - 25 m / s. When β1 = 0°, that is, when the stable combustion block has no rotation, its blocking area is 40%, which is the ratio of the wind blocking area of the stable combustion ring to the cross-sectional area of the primary air passage. After adjusting the included angle β1 between the stable combustion ring and the outlet plane of the primary air passage 7 by rotating the handwheel 18, the range of the primary air outlet velocity is 20 - 28 m / s. The number of stable combustion blocks included in the stable combustion ring is arranged as n, which better adapts to swirl burners of different scales;

[0057] When the boiler operates under the condition of 20 - 30% of the rated load, this is a low - load operation, and a relatively large central recirculation zone is required at the outlet of the swirl burner; the operation is as follows: Rotate the handwheel 18 through the transmission mechanism to make the flame - stabilizing ring rotate, and adjust the angle β1 formed by the flame - stabilizing ring and the outlet plane of the primary air passage 7 to 60° - 90°. After the above operation, the shielding area is 0 - 15%, the primary air outlet wind speed range is 20 - 23 m / s, a relatively large and stable central recirculation zone can be formed at the outlet of the swirl burner. At this time, the distance between the starting position of the central recirculation zone and the burner outlet is 0.15 < a < 0.2d, the length is 1.5d < l < 1.8d, the diameter is 0.5d < D1 < 0.8d, and d is the diameter of the outer secondary air flare - out;

[0058] When the boiler operates under the condition of 30 - 50% of the rated load, this is a medium - load operation, and a relatively large central recirculation zone is still required at the outlet of the swirl burner; the operation is as follows: Rotate the handwheel 18 through the transmission mechanism to make the flame - stabilizing ring rotate, and adjust the angle β1 formed by the flame - stabilizing ring and the outlet plane of the primary air passage 7 to 35° - 60°. After the above operation, the shielding area is 15% - 30%, the primary air outlet wind speed range is 23 - 26 m / s. At this time, the distance between the starting position of the central recirculation zone and the burner outlet is 0.2d < a < 0.25d, the length is 1.0d < l < 1.5d, the diameter is 0.45d < D1 < 0.5d, and d is the diameter of the outer secondary air flare - out;

[0059] When the boiler operates under the condition of higher than 50% of the rated load, this is a high - load operation, and an annular recirculation zone is required at the outlet of the swirl burner; the operation is as follows: Rotate the handwheel 18 through the transmission mechanism to make the flame - stabilizing ring rotate, and adjust the angle β1 formed by the flame - stabilizing ring and the outlet plane of the primary air passage 7 to 0° - 35°. After the above operation, the shielding area is 30% - 40%, the primary air outlet wind speed range is 26 - 28 m / s. The pulverized coal is entrained by the annular recirculation zone to suck in high - temperature flue gas and is ignited and maintained in combustion. The distance between the starting position of the annular recirculation zone and the burner outlet is a > 0.25d, the length is 0.6d < l < 1.0d, the diameter is 0.2d < D2 < 0.4d, and d is the diameter of the outer secondary air flare - out.

[0060] Specific implementation method seven: Combined with Figures 1 to 15 Describe this implementation method. This implementation method provides a use method of a swirl burner with an adjustable flame - stabilizing ring structure. The specific steps of the method are as follows:

[0061] First, install the swirl pulverized coal burner 2 on the front wall 3 and the rear wall 4 of the swirl pulverized coal boiler 1. The installation method adopted is the opposed arrangement. An adjustable flame stabilization ring structure 12 is installed at the burner nozzle. By rotating the handwheel 18, adjust the angle β2 between the flame stabilization ring and the outlet plane of the primary air passage 7, and then adjust the shielding area of the flame stabilization ring and the primary air outlet velocity, so as to achieve the purpose of adjusting the shape and size of the recirculation zone at the burner outlet;

[0062] The range of the primary air outlet velocity is 22 - 25 m / s. When β2 = 0°, that is, when the flame stabilization block does not rotate, its shielding area is 40%, which is the ratio of the wind shielding area of the flame stabilization ring to the cross-sectional area of the primary air passage. After adjusting the angle β2 between the flame stabilization ring and the outlet plane of the primary air passage 7 by rotating the handwheel 18, the range of the primary air outlet velocity is 20 - 28 m / s. The number of flame stabilization blocks included in the flame stabilization ring is arranged as n, which can better adapt to swirl burners of different scales;

[0063] When the boiler operates under the condition of 20 - 30% of the rated load, this is a low-load operation, and a relatively large central recirculation zone is required at the outlet of the swirl burner; the operation is as follows: Rotate the handwheel 18 to make the flame stabilization ring rotate through the transmission mechanism, and adjust the angle β2 formed by the flame stabilization ring and the outlet plane of the primary air passage 7 to 65° - 90°. After the above operation, the shielding area is 0 - 15%, and the range of the primary air outlet velocity is 20 - 23 m / s. A relatively large and stable central recirculation zone can be formed at the outlet of the swirl burner. At this time, the distance between the starting point position of the central recirculation zone and the burner outlet is 0.15 < a < 0.18d, the length is 1.6d < l < 1.9d, and the diameter is 0.5d < D1 < 0.9d, where d is the diameter of the outer secondary air flare;

[0064] When the boiler operates under the condition of 30 - 50% of the rated load, this is a medium-load operation, and a relatively large central recirculation zone is still required at the outlet of the swirl burner; the operation is as follows: Rotate the handwheel 18 to make the flame stabilization ring rotate through the transmission mechanism, and adjust the angle β2 formed by the flame stabilization ring and the outlet plane of the primary air passage 7 to 30° - 65°. After the above operation, the shielding area is 15% - 30%, and the range of the primary air outlet velocity is 23 - 26 m / s. At this time, the distance between the starting point position of the central recirculation zone and the burner outlet is 0.18d < a < 0.21d, the length is 1.2d < l < 1.6d, and the diameter is 0.4d < D1 < 0.5d, where d is the diameter of the outer secondary air flare;

[0065] When the boiler operates at a load above 50% of the rated load, this is a high-load operation, and an annular recirculation zone is required at the outlet of the tangential combustion burner. The operation is as follows: By rotating the handwheel 18 through the transmission mechanism, the flame stabilizer ring rotates, and the angle β2 formed between the flame stabilizer ring and the outlet plane of the primary air passage 7 is adjusted to 0° - 30°. After the above operation, the shielding area is 30% - 40%, the primary air outlet velocity range is 26 - 28 m / s, the pulverized coal is entrained by the high-temperature flue gas in the annular recirculation zone and ignited, and combustion is maintained. The distance a between the starting position of the annular recirculation zone and the burner outlet is a > 0.21d, the length is 0.7d < l < 1.2d, and the diameter is 0.12d < D2 < 0.4d, where d is the diameter of the outer secondary air flare.

[0066] The present invention has been disclosed above with preferred embodiments. However, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or equivalents within the scope of the technical solution of the present invention by using the disclosed structure and technical content. However, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

[0067] Working principle:

[0068] The tangential pulverized coal burner 2 is installed on the front wall 3 and the rear wall 4 of the tangential pulverized coal boiler 1 in a opposed arrangement. The central air enters the furnace through the central air passage 8 arranged in the center of the burner. The primary air enters the furnace through the primary air passage 7. The inner secondary air enters the furnace in a rotating form after passing through the axially adjustable blades 14 in the inner secondary air passage 6. The outer secondary air enters the furnace in a rotating form after passing through the tangential blades 13 in the outer secondary air passage 5. The adjustable flame stabilizer ring structure 12 is installed at the outlet of the primary air passage 7. The transmission mechanism support plate 15 is installed at the outlet of the primary air passage 7. The inner diameter of the outlet of the primary air passage 7 is R. The height of each flame stabilizer ring is h1, the height of the transmission mechanism support plate 15 is h2, and the length of the rotating shaft 16 is h3. When the rotating shaft 16 is arranged radially along the inner diameter of the primary air passage 7, there are n flame stabilizer blocks, corresponding to n groups of gear sets composed of n rotating shafts 16, driving gears 23, and driven gears 24, and n gears 21. The chain 22 meshes with each gear 21. When the rotating shaft 16 is arranged tangentially along the radial direction of the inner diameter of the primary air passage 7, there are n flame stabilizer blocks 17, corresponding to n rotating shafts 16, n groups of worm gears 25 and worm gear sleeves 26, and n gears 21. The chain 22 meshes with each gear 21. The transmission of each flame stabilizer ring in the two adjustable flame stabilizer ring structures is controlled by rotating the handwheel 18. Embodiment

[0069] Taking a supercritical 350MW tangentially fired pulverized coal boiler as an example, it burns Zhundong coal. The boiler adopts the opposed firing mode of front and rear walls, with a total of 5 layers of burners arranged. 3 layers are arranged on the front wall and 2 layers on the rear wall. 4 burners are arranged in each layer, and a total of 20 axial swirl burners are installed. A fixed and unchanged flame stabilizer ring device is installed at the burner nozzle. Before the burner was modified, the minimum stable combustion load without oil injection of the boiler was 40%.

[0070] The burner was modified using the flame stabilizer ring described in "Flame Stabilizer Ring Device for Swirl Burners" (Application (Patent) No.: CN201820964784.3) and applied to the boiler. After the modification, the minimum stable combustion load without oil injection of the boiler was 35%. When the boiler was shut down for maintenance after one year of stable operation, it was found that there were serious burnout and slagging problems at the burner nozzle.

[0071] A swirl burner with an adjustable flame stabilizer ring structure was designed according to the device and method described in this patent ( Figure 2 the structure shown). A model of this swirl burner was established in the laboratory. The geometric ratio between the model burner used in the experiment and the actual burner was 1:2. Through the cold-state single-phase flow characteristic test of the model burner, the following experimental results were obtained.

[0072] For Figure 3 the flame stabilizer ring structure shown, when the rotation axis (16) is arranged radially along the inner diameter of the primary air passage (7), the included angle between the flame stabilizer ring and the outlet plane of the primary air passage (7) is β1. The experimental results are as follows:

[0073] (1) When the included angle β1 between the flame stabilizer ring and the outlet plane of the primary air passage (7) is 60° - 90°, the shielding area of the flame stabilizer ring is 0 - 15%, and the primary air outlet velocity range is 20 - 23 m / s. Under this condition, a large and stable central recirculation zone can be formed at the outlet of the swirl burner. The distance between the starting position of the recirculation zone and the burner outlet is 0.15 < a < 0.2d, the length is 1.5d < l < 1.8d, and the diameter is 0.5d < D1 < 0.8d.

[0074] (2) When the included angle β1 between the flame stabilizer ring and the outlet plane of the primary air passage (7) is 35° - 60°, the shielding area of the flame stabilizer ring is 15% - 30%, and the primary air outlet velocity range is 23 - 26 m / s. Under this condition, the distance between the starting position of the central recirculation zone and the burner outlet is 0.2d < a < 0.25d, the length is 1.0d < l < 1.5d, and the diameter is 0.4d < D1 < 0.5d.

[0075] When the included angle β1 between the stable combustion ring and the outlet plane of the primary air passage (7) is 0° to 35°, the shielding area of the stable combustion ring is 30% to 40%, and the outlet air velocity range of the primary air is 26 to 28 m / s. Under this condition, the distance a between the starting position of the annular recirculation zone formed at the burner outlet and the burner outlet is a > 0.25d, the length is 0.6d < l < 1.0d, and the diameter is 0.2d < D2 < 0.4d.

[0076] For Figure 8 In the stable combustion ring structure shown, when the rotating shaft (16) is arranged along the tangential direction of the inner diameter of the primary air passage (7), the included angle between the stable combustion ring and the outlet plane of the primary air passage (7) is β2, and the experimental results are as follows:

[0077] (1) When the included angle β2 between the stable combustion ring and the outlet plane of the primary air passage (7) is 65° to 90°, the shielding area of the stable combustion ring is 0 to 15%, and the outlet air velocity range of the primary air is 20 to 23 m / s. Under this condition, a relatively large and stable central recirculation zone can be formed at the outlet of the swirl burner. The distance between the starting position of the recirculation zone and the burner outlet is 0.15 < a < 0.18d, the length is 1.6d < l < 1.9d, and the diameter is 0.5d < D1 < 0.9d

[0078] (2) When the included angle β2 between the stable combustion ring and the outlet plane of the primary air passage (7) is 30° to 65°, the shielding area of the stable combustion ring is 15% to 30%, and the outlet air velocity range of the primary air is 23 to 26 m / s. Under this condition, the distance between the starting position of the central recirculation zone and the burner outlet is 0.18d < a < 0.21d, the length is 1.2d < l < 1.6d, and the diameter is 0.4d < D1 < 0.5d.

[0079] (3) When the included angle β2 between the stable combustion ring and the outlet plane of the primary air passage (7) is 0° to 30°, the shielding area of the stable combustion ring is 30% to 40%, and the outlet air velocity range of the primary air is 26 to 28 m / s. Under this condition, the distance between the starting position of the annular recirculation zone formed at the burner outlet and the burner outlet is a > 0.21d, the length is 0.7d < l < 1.2d, and the diameter is 0.2d < D2 < 0.4d.

[0080] Applying the device and method described in this patent to the above-mentioned supercritical 350 MW swirl pulverized coal boiler burning Zhundong coal, the included angle between the stable combustion ring and the outlet plane of the primary air passage can be flexibly adjusted according to different loads of the boiler, so as to adjust the shape and size of the recirculation zone at the burner outlet, better adapt to the combustion of pulverized coal under different loads, avoid burning and slagging at the burner nozzle while ensuring stable combustion, and achieve the goal of flexible peak shaving. Specifically as follows:

[0081] For Figure 3The combustion stabilizing ring structure shown has a rotating shaft (16) arranged radially along the inner diameter of the primary air channel (7). The combustion stabilizing ring is rotated by rotating the rotating handwheel (18), and the angle between the rotating shaft (16) and the outlet plane of the primary air channel (7) is β1.

[0082] (1) When the boiler is running under low load conditions (20~30% of rated load), the stabilizing ring is rotated by turning the handwheel (18) through the transmission mechanism, and the angle β1 between the stabilizing ring and the outlet plane of the primary air channel (7) is adjusted to 60°~90°.

[0083] (2) When the boiler is operating under medium load (30~50% of rated load), the operation is the same as described above, and β1 is adjusted to 35°~60°;

[0084] (3) When the boiler is operating under high load conditions (above 50% of the rated load), the operation is the same as described above, and β1 is adjusted to 0°~35°.

[0085] When the rotating shaft (16) is arranged along the tangential direction of the inner diameter of the primary air passage (7), the stabilizing ring is rotated by rotating the rotating handwheel (18), and the angle between the rotating handwheel (16) and the outlet plane of the primary air passage (7) is β2.

[0086] (1) When the boiler is running under low load conditions (20~30% of rated load), the stabilizing ring is rotated by turning the handwheel (18) through the transmission mechanism, and the angle β2 between the stabilizing ring and the outlet plane of the primary air channel (7) is adjusted to 65°~90°.

[0087] (2) When the boiler is operating under medium load (30~50% of rated load), the operation is the same as described above, but β2 is adjusted to 30°~65°;

[0088] (3) When the boiler is operating under high load conditions (above 50% of the rated load), the operation is the same as described above, and β2 is adjusted to 0°~30°.

[0089] After applying the device and method of the present invention, the minimum non-oil-fueled stable combustion load of the boiler is 30%. After 5 years of normal shutdown and maintenance, there are no problems of burner nozzle burn-out or slagging. Furthermore, it can achieve flexible peak shaving of the boiler under different loads.

Claims

1. A method of using a swirl burner with an adjustable stabilizing ring structure, wherein the swirl burner with the adjustable stabilizing ring structure is provided with an outer secondary air channel (5), an inner secondary air channel (6), a primary air channel (7) and a central air channel (8) in sequence from the outside to the inside. The outer secondary air channel (5) is provided with multiple tangential blades (13) along the circumferential direction, and each tangential blade (13) is equidistantly installed on an annular plate in the outer secondary air channel (5) to form a tangential impeller. An outer secondary air flare (9) is installed at the outlet of the outer secondary air channel (5). The inner secondary air channel (6) is provided with multiple axially adjustable blades (14) along the circumferential direction, and each axially adjustable blade (14) is installed on a sleeve on the outer wall of the inner secondary air channel (6) to form an axially movable impeller. An inner secondary air flare (10) is installed at the outlet of the inner secondary air channel (6), and a primary air flare (11) is installed at the outlet of the primary air channel (7). An adjustable stabilizing ring structure (12) is also installed at the outlet of the primary air channel (7). The adjustable flame stabilizing ring structure (12) includes a transmission mechanism support plate (15), a rotating handwheel (18), a gear baffle (20), a chain (22), n rotating shafts (16), n flame stabilizing blocks (17), n transmission rods (19), n gears (21), n ​​driving bevel gears (23), and n driven bevel gears (24). The transmission mechanism support plate (15) is set in the primary air channel (7), and the outer circular wall of the transmission mechanism support plate (15) is fixedly connected to the inner ring wall of the primary air channel (7). A connecting sleeve is provided at one end of the transmission mechanism support plate (15) near the air outlet, and one end of the connecting sleeve is fixedly connected to the end of the transmission mechanism support plate (15) near the air outlet. The connecting sleeve is coaxially arranged with the transmission mechanism support plate (15). A gap is provided between the outer circular surface of the connecting sleeve and the inner ring wall of the primary air channel (7). n transmission rods (19) are equidistantly inserted along the circumference of the transmission mechanism support plate (15) at the end of the transmission mechanism support plate (15) away from the air outlet. Each transmission rod (19) is rotatably connected to the transmission mechanism support plate (15) through a bearing. One end of each transmission rod (19) passes through the transmission mechanism support plate (15) and is set in the gap between the connecting sleeve and the inner ring wall of the primary air channel (7). The other end of each transmission rod (19) remains outside the end of the transmission mechanism support plate (15) away from the air outlet. The assembly includes a driving bevel gear (23), and n rotating shafts (16) are equidistantly inserted circumferentially on the outer surface of the connecting sleeve. The axis of each rotating shaft (16) is perpendicular to the axis of the connecting sleeve. Each rotating shaft (16) is rotatably connected to the connecting sleeve via a bearing. One end of each rotating shaft (16) extends into the gap between the connecting sleeve and the inner ring wall of the primary air duct (7), and a driven bevel gear (24) is fitted onto one end of each rotating shaft (16). Each driven bevel gear (24) meshes with a corresponding driving bevel gear (23). The other end of each rotating shaft (16) extends into the connecting sleeve, and a [missing information - likely a type of bearing or component] is mounted on the other end of each rotating shaft (16). A stable combustion block (17) is provided. A gear baffle (20) is set at the end of the transmission mechanism support plate (15) away from the air outlet. The gear baffle (20) is sleeved on n transmission rods (19). The gear baffle (20) is set with a clearance fit with each transmission rod (19). The gear baffle (20) is detachably connected to the inner ring wall of the primary air channel (7). Each gear (21) is correspondingly sleeved on a transmission rod (19). A chain (22) is sleeved on n gears (21). The n gears (21) are connected by transmission through the chain (22). A rotating handwheel (18) is set at the end of the gear baffle (20) near the air outlet. The rotating handwheel (18) is installed on the other end of a transmission rod (19). The inner diameter of the outlet of the primary air passage (7) is R. The adjustable flame-stabilizing ring is composed of n flame-stabilizing blocks (17), where the value range of n is 6 - 16. The height of each flame-stabilizing ring is h1 = 7% - 8%R, the height of the driving mechanism support plate (15) is h2 = 3.5% - 4%R, and the length of the rotating shaft (16) is h3 = 1.4 - 1.8h2; Its features are: The specific steps of the method are as follows: First, install the swirl pulverized coal burner (2) on the front wall (3) and rear wall (4) of the swirl pulverized coal boiler (1). The installation method adopted is opposed arrangement. An adjustable flame-stabilizing ring structure (12) is installed at the burner nozzle. By rotating the handwheel (18), adjust the angle β1 between the flame-stabilizing ring and the outlet plane of the primary air passage (7), thereby adjusting the shielding area of the flame-stabilizing ring and the primary air outlet velocity, achieving the purpose of adjusting the shape and size of the recirculation zone at the burner outlet; The range of the primary air outlet velocity is 22 - 25 m / s. When β1 = 0°, that is, when the flame-stabilizing blocks do not rotate, its shielding area is 40%, which is the ratio of the wind-shielding area of the flame-stabilizing ring to the cross-sectional area of the primary air passage. After adjusting the angle β1 between the flame-stabilizing ring and the outlet plane of the primary air passage (7) by rotating the handwheel (18), the range of the primary air outlet velocity is 20 - 28 m / s. The number of flame-stabilizing blocks included in the flame-stabilizing ring is arranged as n, which better adapts to swirl burners of different scales; When the boiler operates under the condition of 20 - 30% of the rated load, this is a low-load operation, and a relatively large central recirculation zone is required at the outlet of the swirl burner; The operation is as follows: Rotate the handwheel (18) to make the flame-stabilizing ring rotate through the transmission mechanism, and adjust the angle β1 between the flame-stabilizing ring and the outlet plane of the primary air passage (7) to 60° - 90°. After the above operation, the shielding area is 0 - 15%, and the range of the primary air outlet velocity is 20 - 23 m / s. A relatively large and stable central recirculation zone can be formed at the outlet of the swirl burner. At this time, the distance between the starting position of the central recirculation zone and the burner outlet is 0.15 < a < 0.2d, the length is 1.5d < l < 1.8d, and the diameter is 0.5d < D1 < 0.8d, where d is the diameter of the outer secondary air flare; When the boiler operates under the condition of 30 - 50% of the rated load, this is a medium-load operation, and a relatively large central recirculation zone is still required at the outlet of the swirl burner; The operation is as follows: Rotate the handwheel (18) to make the flame-stabilizing ring rotate through the transmission mechanism, and adjust the angle β1 between the flame-stabilizing ring and the outlet plane of the primary air passage (7) to 35° - 60°. After the above operation, the shielding area is 15% - 30%, and the range of the primary air outlet velocity is 23 - 26 m / s. At this time, the distance between the starting position of the central recirculation zone and the burner outlet is 0.2d < a < 0.25d, the length is 1.0d < l < 1.5d, and the diameter is 0.45d < D1 < 0.5d, where d is the diameter of the outer secondary air flare; When the boiler operates at a condition with a load higher than 50% of the rated load, this is a high-load operation, and an annular recirculation zone is required to exist at the outlet of the tangential combustion burner; the operation is as follows: by rotating the handwheel (18), the stable combustion ring is rotated through the transmission mechanism, and the included angle β1 between the stable combustion ring and the outlet plane of the primary air passage (7) is adjusted to 0° to 35°. After the above operation, the shielding area is 30% to 40%, the primary air outlet wind speed range is 26 to 28 m / s, the pulverized coal is entrained by the high-temperature flue gas through the annular recirculation zone and is ignited and maintained in combustion. The distance a between the starting position of the annular recirculation zone and the burner outlet is a > 0.25d, the length is 0.6d < l < 1.0d, and the diameter is 0.2d < D2 < 0.4d, where d is the diameter of the outer secondary air flare.

2. A method for using a tangential combustion burner with an adjustable stable combustion ring structure. The tangential combustion burner is successively provided with an outer secondary air passage (5), an inner secondary air passage (6), a primary air passage (7), and a central air passage (8) from outside to inside. A plurality of tangential blades (13) are circumferentially arranged in the outer secondary air passage (5), and each tangential blade (13) is equidistantly installed on the annular plate in the outer secondary air passage (5) to form a tangential blade wheel. An outer secondary air flare (9) is installed at the outlet of the outer secondary air passage (5). A plurality of axially adjustable blades (14) are circumferentially arranged in the inner secondary air passage (6), and each axially adjustable blade (14) is installed on the sleeve on the outer wall of the inner secondary air passage (6) to form an axially movable blade wheel. An inner secondary air flare (10) is installed at the outlet of the inner secondary air passage (6). A primary air flare (11) is installed at the outlet of the primary air passage (7). An adjustable stable combustion ring structure (12) is also installed at the outlet of the primary air passage (7); The adjustable flame stabilizing ring structure (12) includes a transmission mechanism support plate (15), a rotating handwheel (18), a gear baffle (20), a chain (22), n rotating shafts (16), n flame stabilizing blocks (17), n transmission rods (19), n gears (21), n ​​worm gears (25), and n worm sleeves (26). The transmission mechanism support plate (15) is set in the primary air channel (7), and the outer circular wall of the transmission mechanism support plate (15) is fixedly connected to the inner ring wall of the primary air channel (7). The n transmission rods (19) are equidistantly inserted into the transmission mechanism along the circumference of the transmission mechanism support plate (15). On the end of the support plate (15) away from the air outlet, each transmission rod (19) is rotatably connected to the support plate (15) via a bearing. One end of each transmission rod (19) passes through the support plate (15) and is located inside the support plate (15) near the air outlet. The other end of each transmission rod (19) remains outside the support plate (15) away from the air outlet. A worm gear (25) is fitted on one end of each transmission rod (19). n rotating shafts (16) are equidistantly arranged circumferentially at the end of the support plate (15) near the air outlet. The rotating shaft (16) is arranged tangentially along the inner diameter of the primary air duct (7), and a worm gear sleeve (26) is fitted in the middle of each rotating shaft (16). Each rotating shaft (16) is connected to a corresponding worm wheel (25) through the worm gear sleeve (26). Each rotating shaft (16) is fixedly connected to the end of the transmission mechanism support plate (15) near the air outlet through a set of connecting ears. The rotating shaft (16) and the connecting ears are rotatably connected by bearings. Each flame stabilizing block (17) is installed on the outer circumference of a rotating shaft (16). The gear baffle (20) is set on the transmission mechanism support plate (15). At the end furthest from the air outlet, a gear baffle (20) is fitted on n transmission rods (19). The gear baffle (20) is fitted with each transmission rod (19) with a clearance fit. The gear baffle (20) is detachably connected to the inner ring wall of the primary air duct (7). Each gear (21) is fitted on a corresponding transmission rod (19). A chain (22) is fitted on n gears (21). The n gears (21) are connected by the chain (22). A rotating handwheel (18) is set at the end of the gear baffle (20) near the air outlet, and the rotating handwheel (18) is installed on the other end of a transmission rod (19). The outlet inner diameter of the primary air duct (7) is R. The adjustable stabilizing ring is composed of n stabilizing blocks (17), where n ranges from 6 to 16. The height of each stabilizing ring is h1 = 6.3% to 8.7%R. The height of the transmission mechanism support plate (15) is h2 = 3.5% to 4%R. The length of the rotating shaft (16) is h3 = 7.2 to 8.1h2. Its features are: The specific steps of the method are as follows: First, install the swirl pulverized coal burner (2) on the front wall (3) and rear wall (4) of the swirl pulverized coal boiler (1). The installation method adopted is opposed arrangement. An adjustable flame stabilization ring structure (12) is installed at the burner nozzle. By rotating the handwheel (18), the included angle β2 between the flame stabilization ring and the outlet plane of the primary air passage (7) is adjusted, thereby adjusting the shielding area of the flame stabilization ring and the primary air outlet velocity, so as to achieve the purpose of adjusting the shape and size of the recirculation zone at the burner outlet; The primary air outlet velocity ranges from 22 to 25 m / s. When β2 = 0°, that is, when the flame stabilization block has no rotation, its shielding area is 40%, which is the ratio of the wind shielding area of the flame stabilization ring to the cross-sectional area of the primary air passage. After adjusting the included angle β2 between the flame stabilization ring and the outlet plane of the primary air passage (7) by rotating the handwheel (18), the primary air outlet velocity ranges from 20 to 28 m / s. The number of flame stabilization blocks included in the flame stabilization ring is arranged as n, which can better adapt to swirl burners of different scales; When the boiler operates under the condition of 20 - 30% of the rated load, this is a low-load operation, and a relatively large central recirculation zone is required at the outlet of the swirl burner. The operation is as follows: Rotate the handwheel (18) to make the flame stabilization ring rotate through the transmission mechanism, and adjust the included angle β2 between the flame stabilization ring and the outlet plane of the primary air passage (7) to 65° - 90°. After the above operation, the shielding area is 0 - 15%, and the primary air outlet velocity ranges from 20 to 23 m / s. A relatively large and stable central recirculation zone can be formed at the outlet of the swirl burner. At this time, the distance between the starting point of the central recirculation zone and the burner outlet is 0.15 < a < 0.18d, the length is 1.6d < l < 1.9d, and the diameter is 0.5d < D1 < 0.9d, where d is the diameter of the outer secondary air flare; When the boiler operates under the condition of 30 - 50% of the rated load, this is a medium-load operation, and a relatively large central recirculation zone is still required at the outlet of the swirl burner. The operation is as follows: Rotate the handwheel (18) to make the flame stabilization ring rotate through the transmission mechanism, and adjust the included angle β2 between the flame stabilization ring and the outlet plane of the primary air passage (7) to 30° - 65°. After the above operation, the shielding area is 15% - 30%, and the primary air outlet velocity ranges from 23 to 26 m / s. At this time, the distance between the starting point of the central recirculation zone and the burner outlet is 0.18d < a < 0.21d, the length is 1.2d < l < 1.6d, and the diameter is 0.4d < D1 < 0.5d, where d is the diameter of the outer secondary air flare; When the boiler operates at a condition with a load higher than 50% of the rated load, this is a high-load operation, and an annular recirculation zone is required at the outlet of the tangential burner; the operation is as follows: by rotating the handwheel (18), the stable combustion ring is rotated through the transmission mechanism, and the angle β2 formed between the stable combustion ring and the outlet plane of the primary air passage (7) is adjusted to 0° - 30°. After the above operation, the shielding area is 30% - 40%, the primary air outlet wind speed range is 26 - 28 m / s, the pulverized coal is entrained by the high-temperature flue gas through the annular recirculation zone and ignited, and the combustion is maintained. The distance a between the starting position of the annular recirculation zone and the burner outlet is a > 0.21d, the length is 0.7d < l < 1.2d, and the diameter is 0.12d < D2 < 0.4d, where d is the diameter of the outer secondary air flare.

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