Search

CN-122015089-A - Dual cycle fuel grading low-nitrogen combustor

CN122015089ACN 122015089 ACN122015089 ACN 122015089ACN-122015089-A

Abstract

The application relates to the technical field of industrial burners, and particularly discloses a dual-cycle fuel grading low-nitrogen burner which comprises a shell, wherein a first fuel system and a second fuel system are coaxially arranged in the shell, the first fuel system is arranged in the middle of the shell and comprises a first combustion channel, a swirl burner and a first-stage fuel nozzle, the first combustion channel, the swirl burner and the first-stage fuel nozzle are sequentially communicated from inside to outside, the swirl burner is fixedly arranged in the first combustion channel, the first-stage fuel nozzle is arranged at the outlet end of the first combustion channel and is used for spraying primary main fuel, the second fuel system comprises a plurality of groups of second-stage spray guns, and the second-stage spray guns are uniformly distributed along the circumferential direction of the shell and are positioned at the periphery of the first combustion channel. The secondary spray gun is used for spraying secondary grade fuel. The application can ensure the stability of flame and the continuous low value of nitrogen oxide emission.

Inventors

  • LI SHIWEI
  • BAI ZHISHAN
  • HUANG QINGHAI
  • MA LIKUN
  • YAN XINYAN
  • SONG YUEJIA

Assignees

  • 华东理工大学

Dates

Publication Date
20260512
Application Date
20260403

Claims (10)

  1. 1. A dual cycle fuel staged low nitrogen burner comprising: A housing (1); The first fuel system (2) is coaxially arranged in the shell (1), the first fuel system (2) is arranged in the middle of the shell (1), the first fuel system (2) comprises a first combustion channel (21), a swirl burner (22) and a primary fuel nozzle (23), the swirl burner (22) is arranged in the first combustion channel (21), and the primary fuel nozzle (23) is arranged at the outlet end of the first combustion channel (21); The second fuel system (3) is coaxially arranged in the shell (1), the second fuel system (3) comprises a plurality of groups of secondary spray guns (31), the groups of secondary spray guns (31) are distributed along the circumferential direction of the shell (1), the secondary spray guns (31) are arranged at the periphery of the first combustion channel (21), and The primary flue gas channel is connected with the hearth and the inlet of the secondary spray gun (31) and is used for injecting flue gas in a high-temperature area of the hearth to the inlet of the secondary spray gun (31); The secondary flue gas channel is connected with the primary flue gas channel in series, the secondary flue gas channel is connected with the outlet of the secondary spray gun (31) and the main combustion zone, and the secondary flue gas channel is used for injecting flue gas to the first fuel system (2).
  2. 2. A dual cycle fuel staged low nitrogen burner as defined in claim 1, wherein said swirl stabilizer (22) includes a central shaft (221) and a plurality of vanes (222) disposed on said central shaft (221), said vanes (222) having an inclination angle of 30 ° -60 °.
  3. 3. The dual cycle fuel staged low nitrogen burner as defined in claim 1, wherein said primary fuel nozzle (23) is provided with a plurality of small holes having a diameter of 20mm or more, said small holes being distributed in a circumferential array for forming a recirculation zone behind said primary fuel nozzle (23) having a size of 1.2-1.8 times the diameter of said primary fuel nozzle (23).
  4. 4. A dual cycle fuel staged low nitrogen burner as claimed in claim 1, wherein the number N of secondary lances (31) of said secondary fuel system (3) satisfies the relation N≥6+0.02× (D-200), where D is the diameter of said housing (1) in mm.
  5. 5. A dual cycle fuel staged low nitrogen burner as claimed in claim 1, wherein the secondary lance (31) has an outlet flow rate of 150-290 m/s, the axis of the secondary lance (31) being at an angle of 15-45 DEG to the main axis of the housing (1).
  6. 6. The dual-cycle fuel-graded low-nitrogen burner of claim 1, wherein the burner head is further integrated with a waste acid atomizing spray gun, the atomizing medium of the waste acid atomizing spray gun is compressed air, the working pressure is more than or equal to 0.5 MPa, and the atomizing particle size is less than or equal to 50 μm.
  7. 7. The dual-cycle fuel staged low-nitrogen burner as claimed in claim 1, wherein two ultraviolet flame detectors are symmetrically arranged on two sides of the burner housing (1), and the detection wavelength of the ultraviolet flame detectors is 185-260 nm and is connected with a flameout protection cut-off valve.
  8. 8. A dual cycle fuel staged low nitrogen burner as claimed in claim 2, wherein the vanes (222) of the swirl stabilizer (22) are coated with a refractory coating and/or the primary fuel nozzle (23) is of a refractory ceramic material.
  9. 9. A dual cycle fuel staged low nitrogen burner as defined in claim 1, wherein the fuel supply to the burner is configured such that primary fuel comprises 40-50% of the total mass of fuel and secondary fuel comprises 50-60% of the total mass of fuel.
  10. 10. The dual cycle fuel staged low nitrogen burner as defined in claim 1, wherein an outer cycle flue gas interface is provided on the side wall of the housing (1), the outer cycle interface is located in the middle section of the housing (1), the outer cycle interface is 300-500 mm from the primary nozzle outlet, and the interface diameter is 50-80 mm.

Description

Dual cycle fuel grading low-nitrogen combustor Technical Field The application relates to the technical field of industrial burners, in particular to a double-circulation fuel grading low-nitrogen burner. Background A burner is a device for mixing and burning fuel and air in a certain manner. The low-nitrogen burner is an environment-friendly device for providing heat energy for an industrial fuel or gas boiler, and reduces nitrogen oxide (NOx) emissions and improves combustion efficiency by optimizing a combustion structure. The core principle of the method comprises the technologies of staged combustion, flue Gas Recirculation (FGR), premixed combustion and the like, and the method inhibits the generation of NOx by controlling the mixing proportion of fuel and air, reducing the combustion temperature and the like, so that the method has the emission index of generally lower than 30mg/m < 3 >, and is suitable for heat supply boilers, industrial kilns and commercial places. The traditional fuel classification system has large NOx emission fluctuation (> 50%) when the load changes, is easy to extinguish under the low load working condition and has poor stability, and secondly, the external FGR system needs an additional fan and a pipeline, so that the energy consumption of the system is increased by about 12-15%, and the condensation corrosion problem is possibly caused by that the temperature of the flue gas is lower than the dew point. Disclosure of Invention The application provides a double-circulation fuel grading low-nitrogen burner for solving the problem of poor stability of the existing combustion grading system. The application provides a double-circulation fuel grading low-nitrogen burner, which adopts the following technical scheme: A dual cycle fuel staged low nitrogen burner comprising: A housing; The first fuel system is coaxially arranged in the shell, the first fuel system is arranged in the middle of the shell, the first fuel system comprises a first combustion channel, a swirl burner and a primary fuel nozzle, the swirl burner is arranged in the first combustion channel, and the primary fuel nozzle is arranged at the outlet end of the first combustion channel; The second fuel system is coaxially arranged in the shell and comprises a plurality of groups of secondary spray guns, a plurality of groups of secondary spray guns are arranged along the circumferential direction of the shell and are arranged at the periphery of the first combustion channel, and The first-stage flue gas channel is connected with the hearth and the second-stage spray gun inlet and is used for injecting flue gas in a high-temperature area of the hearth to the second-stage spray gun inlet; and the secondary flue gas channel is connected with the primary flue gas channel in series, and is connected with the outlet of the secondary spray gun and the main combustion area and is arranged in the first fuel system for injecting flue gas. By adopting the technical scheme, the built-in double-circulation flue gas recirculation without an external high-power FGR fan is realized by constructing the built-in primary flue gas channel and the built-in secondary flue gas channel. The primary high-temperature flue gas is premixed with the secondary fuel, so that a strong reducing atmosphere is created, NOx is reduced efficiently, and the secondary low-temperature flue gas dilutes the main combustion area and reduces oxygen concentration and flame temperature. The primary flue gas channel and the secondary flue gas channel are deeply cooperated with the first fuel system and the second fuel system, so that the combustor can realize deep low-nitrogen combustion (NOx is less than 30mg/m <3 >) without a complex external system, and the system has low energy consumption and compact structure, and avoids the corrosion risk of external FGR. In some embodiments, the swirl stabilizer includes a central shaft and a plurality of blades disposed on the central shaft, the blades having an inclination angle of 30 ° -60 °. In some embodiments, the primary fuel nozzle is provided with a plurality of small holes, the aperture diameter of the small holes is larger than or equal to 20mm, the small holes are distributed in a circumferential array, and the small holes are used for forming a backflow zone with a size which is 1.2-1.8 times of the diameter of the primary fuel nozzle behind the primary fuel nozzle. In some embodiments, the number N of secondary guns of the second fuel system satisfies the relationship N+.6+0.02× (D-200), where D is the diameter of the housing in mm. In some embodiments, the outlet flow rate of the secondary lance is 150-290 m/s and the axis of the secondary lance is at an angle of 15 ° -45 ° to the main axis of the housing. In some embodiments, the burner head is also integrated with a waste acid atomizing spray gun, the atomizing medium of the waste acid atomizing spray gun is compressed air, the working pressure is more t