Low nitrogen burner

Abstract

The invention relates to the technical field of burners and discloses a low-nitrogen burner. The excess air coefficient of a primary air nozzle in a main combustion chamber is set between 0.25 and 0.8, so that the gas and air in the main combustion chamber are fully burned through a primary rich fuel and the oxygen content of the combustion product is reduced. Then, part of the flue gas in the main combustion chamber is introduced through the flame nozzle, and the temperature of the ejected primary rich fuel flame is reduced through the dilution effect of the flue gas. The flue gas is then entrained by a high-speed secondary air jet to dilute the oxygen concentration in the air and is mixed with the primary rich fuel flame at a long distance in an angle delay manner for further combustion to form a secondary combustion flame. During the secondary combustion, the primary rich fuel is slowly and at a low temperature, which effectively inhibits the generation of nitrogen oxides. Combined with the primary combustion in a fuel-rich mode, the fuel is fully burned, and the oxygen content of the combustion product is reduced to below 100 ppm after the combustion is completed, so as to reduce the generation of thermal NOx and achieve high-efficiency low-nitrogen combustion.

Description

Technical Field

[0001] The invention belongs to the technical field of burners, and in particular relates to a low-nitrogen burner. Background Art

[0002] During the gas combustion process, the emission of nitrogen oxides (NOx) has become an environmental problem that needs to be solved urgently. Traditional burner designs often find it difficult to effectively control the generation of nitrogen oxides while pursuing efficient combustion. Since gas combustion involves high temperatures and oxygen-rich environments, these factors will accelerate the formation of nitrogen oxides, posing a serious threat to the atmospheric environment. Although a variety of emission reduction technologies have been proposed, how to effectively reduce nitrogen oxide emissions without sacrificing combustion efficiency is still a major challenge in the current field of combustion technology. Therefore, the development of a new type of burner that can take into account both efficient combustion and low nitrogen oxide emissions has important practical significance and application value. Summary of the invention

[0003] The purpose of the present invention is to overcome the problem that the existing burners generate high nitrogen oxide content during combustion and to provide a low-nitrogen burner that effectively inhibits the generation of nitrogen oxides.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] The low nitrogen burner comprises a shell and a main burner; the shell is provided with a gas delivery channel and an air delivery channel located inside; the main burner is provided with a main combustion chamber located inside the shell and a combustion nozzle connected to one side of the main combustion chamber and extending out of the shell outside, the end of the combustion nozzle is provided with a flame nozzle arranged along the axial direction, the main combustion chamber is provided with a gas nozzle connected to the gas delivery channel and a primary air nozzle connected to the air delivery channel, the primary air flow rate delivered by the primary air nozzle in the main combustion chamber relative to the gas flow rate delivered by the gas nozzle has an air excess coefficient of 0.25 to 0.8; the shell is provided with a plurality of secondary air nozzles arranged around the outside of the flame nozzle along the axial direction. The gas nozzle and the secondary air nozzle are inclined outward relative to the axial direction, the flame nozzle and the secondary air nozzle are relatively staggered by a distance L in the axial direction, and the aperture of the secondary air nozzle is φ, wherein 5φ≤L≤50φ; the main combustion chamber is used to mix and burn the primary air jet generated by the primary air nozzle and the gas jet generated by the gas nozzle to produce a primary fuel-rich flame, which is ejected through the combustion nozzle and then slowly mixed with the secondary air jet transported over a long distance from the secondary air nozzle and further burned to form a secondary combustion flame; the gas nozzle is used to draw part of the smoke in the main combustion chamber, and reduce the temperature of the ejected primary fuel-rich flame by the dilution effect of the smoke.

[0006] Compared with the prior art, in the low-nitrogen burner of the present invention, the excess air coefficient of the primary air nozzle in the main combustion chamber is set between 0.25 and 0.8, so that the gas and air in the main combustion chamber are fully burned through the primary rich fuel and the oxygen content of the combustion products is reduced, and then part of the flue gas in the main combustion chamber is introduced through the flame nozzle, and the temperature of the ejected primary rich fuel flame is reduced by the dilution effect of the flue gas, and then the flue gas is entrained by the high-speed secondary air jet to dilute the oxygen concentration in the air and is mixed with the primary rich fuel flame at a long distance in an angle delay manner for further combustion to form a secondary combustion flame, so that the primary rich fuel is carried out slowly and at a low temperature during the secondary combustion process, effectively inhibiting the formation of nitrogen oxides, and combining the primary combustion in the fuel-rich mode to ensure that the fuel is fully burned. After the combustion is completed, the oxygen content of the combustion products is reduced to below 100ppm, so as to reduce the formation of thermal NOx and achieve high-efficiency low-nitrogen combustion.

[0007] Furthermore, one side of the inner radial flame nozzle of the combustion nozzle gradually narrows, and the reduction angle A at which the inner radial flame nozzle of the combustion nozzle gradually narrows is (0°, 45°), and the reduction angle A refers to the angle at which the inner radial flame nozzle of the combustion nozzle gradually narrows. Through such an arrangement, the combustion nozzle has a better ability to draw out smoke, and the combustion nozzle is arranged as a reduction nozzle with a gradually narrowing inner diameter to accelerate the ejection speed of the first-stage fuel-rich flame and reduce the flow resistance, and the mutual induced effect between the first-stage fuel-rich flame and the smoke is better.

[0008] Furthermore, the shell is provided with a plurality of secondary air injection parts which are arranged around the outside of the flame nozzle, the secondary air injection parts extend out of the outside or inside of the shell, the secondary air nozzles are opened on the secondary air injection parts, and the thickness of the secondary air injection parts is greater than the thickness of the shell wall; through such an arrangement, the secondary air nozzles have a certain thickness, in order to ensure that the secondary air jet has directionality and avoid the formation of a flat jet without an inclination angle due to the thin thickness of the secondary air nozzles.

[0009] Furthermore, the ratio of the gas delivery channel to the main combustion chamber through the gas nozzle is 100%. The excess air coefficient is 0.25 to 0.5, and 5φ≤L≤40φ.

[0010] Furthermore, the gas delivery channel is arranged on the inner side of the air delivery channel, and a plurality of primary air nozzles are provided and arranged around the outer side of the gas nozzle; the primary air nozzle is arranged inclined toward one side of the gas nozzle, and the inclination angle of the primary air nozzle is (0°, 45°); through such an arrangement, the primary air jet generated by the primary air nozzle and the gas jet generated by the gas nozzle are fully mixed, and the effect of full combustion of the first-level rich fuel is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Schematic diagram of the low nitrogen burner of the present invention.

[0012] Figure 2 A side view of the invented low nitrogen burner.

[0013] Figure 3 It is the principle diagram of the low nitrogen burner of the present invention.

[0014] Figure 4 It is a schematic diagram of the working state of the low nitrogen burner of the present invention.

[0015] Explanation of reference numerals: shell 1, main burner 2, gas delivery channel 3, air delivery channel 4, main combustion chamber 21, combustion nozzle 22, flame nozzle 23, primary air nozzle 24, secondary air nozzle 11, secondary air injection part 12, gas nozzle 25, primary fuel-rich flame 5, secondary combustion flame 6.

[0016] Attached Figure 4 In the figure, B is a secondary fuel-rich flame (a mixture of a primary fuel-rich flame and flue gas, a diluted relatively low-temperature fuel-rich flame), C is a primary fuel-rich flame, D is the flue gas entrained by a high-speed fuel-rich flame jet, E is a mixture of secondary air and flue gas (oxygen-depleted jet), F is the flue gas entrained by a high-speed secondary air jet, and G is secondary air. DETAILED DESCRIPTION

[0017] The specific implementation of the present invention is described below in conjunction with the accompanying drawings. In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0018] See also Figures 1 to 4The low nitrogen burner of the present invention comprises a shell 1, a main burner 2 and an igniter; the shell 1 is provided with a gas delivery channel 3 and an air delivery channel 4 located inside; the main burner 2 is provided with a main combustion chamber 21 located inside the shell 1 and a combustion nozzle 22 connected to one side of the main combustion chamber 21 and extending out of the shell 1. The end of the combustion nozzle 22 is provided with a flame nozzle 23 arranged along the axial direction. The main combustion chamber 21 is provided with a gas nozzle 25 connected to the gas delivery channel 3 and a primary air nozzle 24 connected to the air delivery channel 4. The primary air flow rate delivered by the primary air nozzle 24 in the main combustion chamber 21 is 0.25 to 0.8 relative to the gas flow rate delivered by the gas nozzle 25. The shell 1 is provided with a plurality of flame nozzles 23 arranged around the flame nozzle 23 in the axial direction. The secondary air nozzle 11 is arranged outside the opening 23, and the secondary air nozzle 11 is inclined outward relative to the axial direction. The flame nozzle 23 and the secondary air nozzle 11 are relatively staggered in the axial direction by a distance L, and the aperture of the secondary air nozzle 11 is φ, wherein 5φ≤L≤50φ; the main combustion chamber 21 is used for mixing and burning the primary air jet generated by the primary air nozzle 24 and the gas jet generated by the gas nozzle 25 to produce a first-level fuel-rich flame 5, which is ejected through the combustion nozzle 22 and then slowly mixed with the secondary air jet transported by the secondary air nozzle 11 over a long distance, and then further burned to form a second-level combustion flame 6; the gas nozzle 25 is used for ejecting part of the smoke in the main combustion chamber 21, and reducing the temperature of the ejected first-level fuel-rich flame 5 by the dilution effect of the smoke.

[0019] See also Figures 1 to 4When the low-nitrogen burner of the present invention is working, the excess air coefficient of the primary air nozzle 24 in the main combustion chamber 21 is set to between 0.25 and 0.8, so that the gas and air in the main combustion chamber 21 are fully burned through the primary rich fuel and the oxygen content of the combustion product is reduced to below 100ppm, reducing thermal NOx The remaining unburned rich fuel forms smoke. Since the main combustion chamber 21 continuously generates smoke during the rich fuel combustion process, the flame nozzle 23 continuously draws out the smoke in the main combustion chamber 21 while generating the primary rich fuel flame 5, forming a high-speed jet smoke. When the high-speed jet smoke is ejected, it will dilute and cool the ejected primary rich fuel flame 5, so that the primary rich fuel flame 5 is pulled out to a farther distance for combustion, and the combustion process of the primary rich fuel flame 5 is carried out slowly and at a low temperature. Since the high-speed jet smoke will diffuse to the periphery of the primary rich fuel flame 5 after being ejected, and the flame nozzle 23 and the secondary air nozzle 11 are relatively staggered in the axial direction by a distance value L, which is set to L≥5φ, so that the secondary air nozzle 11 set at an outward inclination angle After the high-speed secondary air jet is generated and sucks the peripheral flue gas and dilutes the oxygen concentration in the air, it can delay mixing and further oxygen-poor combustion to form a secondary combustion flame 6 at a longer distance and a wider range, so that the primary fuel-rich combustion is carried out slowly and at low temperature in an oxygen-poor environment during the secondary combustion, effectively suppressing the generation of nitrogen oxides; in the process of continuous ejection of the high-speed jet flue gas and the primary fuel-rich flame 5 from the flame nozzle 23, the peripheral flue gas can be sucked at the same time, so that the peripheral diffused circulating flue gas is cooled and then flows back to the primary fuel-rich flame 5 for complete combustion, so that the primary fuel-rich flame 5 is better mixed with the high-speed secondary air jet at a low temperature for oxygen-poor combustion, better suppressing the generation of nitrogen oxides, and realizing high-efficiency and low-nitrogen combustion.

[0020] Compared with the prior art, in the low-nitrogen burner of the present invention, the air excess coefficient of the primary air nozzle 24 in the main combustion chamber 21 is set to between 0.25 and 0.8, so that the gas and air in the main combustion chamber 21 are fully burned through the first-level rich fuel and the oxygen content of the combustion products is reduced, and then part of the flue gas in the main combustion chamber 21 is drawn out through the flame nozzle 23, and the temperature of the ejected first-level rich fuel flame 5 is reduced by the dilution effect of the flue gas, and then the flue gas is entrained by the high-speed secondary air jet to dilute the oxygen concentration in the air and is mixed with the first-level rich fuel flame 5 at a long distance in an angle delay manner for further combustion to form a secondary combustion flame 6, so that the first-level rich fuel is carried out slowly and at a low temperature during the secondary combustion process, effectively inhibiting the formation of nitrogen oxides, and combining the first-level combustion as a rich fuel mode to ensure that the fuel is fully burned, and after the combustion is completed, the oxygen content of the combustion products is reduced to below 100ppm, so as to reduce the formation of thermal NOx and achieve high-efficiency low-nitrogen combustion.

[0021] The low nitrogen burner of the present invention has the following advantages and effects: 1. Effectively reduce the emission of nitrogen oxides and meet the low nitrogen emission standards stipulated by the state or industry. 2. Improve combustion efficiency, ensure full utilization of gas, and reduce energy consumption. 3. Simple structure, easy to install and maintain, with good reliability and stability. 4. Able to adapt to different gas combustion conditions and has wide applicability.

[0022] See also Figures 2 to 4 In one embodiment, one side of the inner radial flame nozzle 23 of the combustion nozzle 22 gradually narrows, and the reduction angle A at which the inner radial flame nozzle 23 gradually narrows is (0°, 45°), for example, A is 10°, 20°, 30° or 40°, and the reduction angle A refers to the angle at which the inner radial flame nozzle 23 of the combustion nozzle 22 gradually narrows. By setting it in this way, the flame nozzle 23 has a better ability to draw out smoke, and the combustion nozzle 22 is set as a reducing nozzle with a gradually narrowing inner diameter to accelerate the ejection speed of the first-level fuel-rich flame 5 and reduce the flow resistance, so that the drawing effect between the first-level fuel-rich flame 5 and the smoke is better.

[0023] In one embodiment, the axial inclination angle of the secondary air nozzle 11 is [0°, 45°], for example, the axial inclination angle is 10°, 20°, 30° or 40°; wherein 5φ≤L≤40φ.

[0024] See also Figures 2 to 4 In one embodiment, the shell 1 is provided with a plurality of secondary air injection portions 12 arranged around the outside of the flame nozzle 23, and the secondary air injection portion 12 extends out of the outside or inside of the shell 1. In this embodiment, the secondary air injection portion 12 extends out of the outside of the shell 1, and the secondary air nozzle 11 is opened on the secondary air injection portion 12, and the thickness of the secondary air injection portion 12 is greater than the wall thickness of the shell 1; through such an arrangement, the secondary air nozzle 11 has a certain thickness, in order to ensure that the secondary air jet has directionality and avoid the formation of a flat jet without an inclination angle due to the thin thickness of the secondary air nozzle 11.

[0025] See also Figures 2 to 4 In one embodiment, the ratio of the gas delivery channel 3 to the main combustion chamber 21 through the gas nozzle 25 is 100%. The air excess coefficient is 0.25 to 0.5, and 5φ≤L≤40φ.

[0026] See also Figures 2 to 4In one embodiment, the gas delivery channel 3 is arranged inside the air delivery channel 4, a plurality of primary air nozzles 24 are provided and are arranged around the outside of the gas nozzle 25, and a plurality of gas nozzles 25 are provided and are arranged in different injection directions; the primary air nozzles 24 are arranged inclined toward one side of the gas nozzle 25, and the inclination angle of the primary air nozzles 24 is (0°, 45°); through such an arrangement, the primary air jet generated by the primary air nozzle 24 and the gas jet generated by the gas nozzle 25 are fully mixed, and the primary rich fuel has a better full combustion effect.

[0027] In one embodiment, the inner diameter of the combustion nozzle 22 is smaller than the inner diameter of the main combustion chamber 21, and the combustion nozzle 22 and the main combustion chamber 21 are connected via an arc transition, and the combustion nozzle 22 and the main combustion chamber 21 are an integrated structure.

[0028] In one embodiment, the value of L may be in the following ranges: 5φ≤L≤10φ, 4φ≤L≤10φ, 4φ≤L≤20φ, 4φ≤L≤30φ, 4φ≤L≤40φ, 4φ≤L≤50φ.

[0029] In one embodiment, the excess air coefficient may be 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75 or 0.8.

[0030] According to the disclosure and teaching of the above description, those skilled in the art to which the present invention belongs may also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. Low nitrogen burner, characterized in that: include: The shell is provided with a gas delivery channel and an air delivery channel located inside; The main burner is provided with a main combustion chamber located inside the shell and a combustion nozzle connected to one side of the main combustion chamber and extending outside the shell, the end of the combustion nozzle is provided with a flame nozzle arranged along the axial direction, the main combustion chamber is provided with a gas nozzle connected to the gas delivery channel and a primary air nozzle connected to the air delivery channel, and the air excess coefficient of the primary air flow delivered by the primary air nozzle in the main combustion chamber relative to the gas flow delivered by the gas nozzle is 0.25 to 0.8; The shell is provided with a plurality of secondary air nozzles arranged around the outer side of the flame nozzle, the secondary air nozzles are inclined outward relative to the axial direction, the flame nozzles and the secondary air nozzles are staggered relative to each other along the axial direction by a distance L, and the aperture of the secondary air nozzles is φ, wherein 5φ≤L≤50φ; The main combustion chamber is used to mix and burn the primary air jet generated by the primary air nozzle and the gas jet generated by the gas nozzle to produce a first-level fuel-rich flame, which is then ejected through the combustion nozzle and slowly mixed with the secondary air jet transported over a long distance from the secondary air nozzle and further burned to form a secondary combustion flame. The gas nozzle is used to draw part of the flue gas in the main combustion chamber and reduce the temperature of the ejected first-level fuel-rich flame through the dilution effect of the flue gas.

2. The low nitrogen burner according to claim 1, characterized in that: The inner radial side of the combustion nozzle gradually narrows.

3. The low nitrogen burner according to claim 2, characterized in that: The gradually narrowing reduction angle A on one side of the radial flame nozzle in the combustion nozzle is (0°, 45°).

4. The low nitrogen burner according to claim 1, characterized in that: The axial inclination angle of the secondary air nozzle is [0°, 45°].

5. The low nitrogen burner according to claim 1 or 4, characterized in that: The shell is provided with a plurality of secondary air injection parts arranged around the outer side of the flame nozzle, the secondary air injection parts extend out of the outer side or the inner side of the shell, the secondary air nozzle is opened on the secondary air injection parts, and the thickness of the secondary air injection parts is greater than the shell wall thickness.

6. The low nitrogen burner according to claim 1, characterized in that: The proportion of the gas delivery channel delivering gas to the main combustion chamber through the gas nozzle is 100%.

7. The low nitrogen burner according to claim 1, characterized in that: The air excess coefficient is 0.25 to 0.5, and 5φ≤L≤40φ.

8. The low nitrogen burner according to claim 1, characterized in that: The gas delivery channel is arranged inside the air delivery channel, and a plurality of primary air nozzles are provided and arranged around the outside of the gas nozzles.

9. The low nitrogen burner according to claim 8, characterized in that: The primary air nozzle is arranged tilted toward one side of the gas nozzle, and the inclination angle of the primary air nozzle is (0°, 45°).

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