Main flame gathering type low nitrogen oxide burner nozzle

Abstract

The invention discloses a main flame gathering type low nitrogen oxide burner nozzle, and belongs to the technical field of burners. The problems that thermal nitric oxide is generated due to the fact that the temperature of an existing natural gas hydrogen-doped combustor is too high, and tempering or blow-off exists in combustion of mixed fuel are solved. The air channel is coaxially arranged on the outer side of the central fuel channel in a sleeving mode, a plurality of main fuel channels are evenly distributed on the outer side of the air channel in the circumferential direction, the main fuel channels are located in the furnace body, and the main fuel sleeve is arranged on a main fuel channel conical opening in a sleeving mode. The main fuel channel inlet section, the main fuel channel conical opening and the main fuel sleeve gradually gather towards the center fuel channel along the same axis, and each main fuel sleeve is provided with a plurality of sleeve smoke inlets in the circumferential direction. Main fuel is input through the multiple main fuel channels, the uniformity of main flame can be improved, the flame temperature can be reduced, accordingly, generation of thermal nitrogen oxide is reduced, and the flame stability can be improved by means of two-stage supply of the fuel through the center fuel channel and the multiple main fuel channels.

Description

Technical Field

[0001] The invention relates to a main flame convergence type low nitrogen oxide burner nozzle, belonging to the technical field of burners. Background Art

[0002] Under the background goal of "dual carbon", my country attaches more importance to the development and exploration of renewable energy. At present, natural gas has been widely used due to its advantages of high safety, high calorific value and low price. Hydrogen is a common carbon-free energy with low minimum ignition energy and wide flammable range. It has received more and more attention in recent years, so it is expected to become an alternative energy source to fossil energy. Natural gas blending with hydrogen can comprehensively utilize the advantages of natural gas and hydrogen, optimize the combustion characteristics of fuel, and is an effective solution to achieve the "dual carbon" goal in the gas field.

[0003] Although gas fuel combustion produces less pollutants than pulverized coal, the pollutant emission characteristics and flame stability characteristics of existing natural gas-hydrogen blended burners are very worthy of attention. Due to its high flame temperature, thermal nitrogen oxides will still be produced. At the same time, due to the large difference in the combustion characteristics of hydrogen and natural gas, if not properly controlled, the combustion of the mixed fuel has the risk of flashback or flameout. Summary of the invention

[0004] The present invention aims to solve the problem of thermal nitrogen oxides generated by the combustion of existing natural gas hydrogen-blended burners and unstable combustion process, and further provides a main flame convergence type low nitrogen oxide burner nozzle.

[0005] The technical solution adopted by the present invention to solve the above technical problems is:

[0006] A main flame convergent low nitrogen oxide burner nozzle, comprising a central fuel pipeline, an air channel, multiple main fuel channels and multiple main fuel sleeves, the air channel is coaxially sleeved on the outside of the central fuel channel, multiple main fuel channels are circumferentially evenly distributed on the outside of the air channel, the main fuel channel is in a furnace body, the head end of the main fuel channel is the main fuel channel inlet section, the main fuel channel inlet section is fixedly connected to the furnace body, the end of the main fuel channel is the main fuel channel tapered opening, the main fuel sleeve is sleeved on the corresponding main fuel channel tapered opening, the main fuel channel inlet section, the main fuel channel tapered opening and the main fuel sleeve gradually converge toward the central fuel channel along the same axis in the furnace body, and each main fuel sleeve has multiple sleeve smoke inlets circumferentially.

[0007] Furthermore, the main fuel channel and the main fuel sleeve are located on the same axis and maintain an angle of 10-20° with the axis of the central fuel channel.

[0008] Furthermore, the air channel and the main fuel channel are fixedly connected to the furnace wall of the furnace body.

[0009] Furthermore, the number of the main fuel channels is 3-16.

[0010] Furthermore, the minimum distance between the outer wall of the main fuel sleeve and the outer wall of the air passage does not exceed the outer diameter of the main fuel sleeve.

[0011] Furthermore, the tapered opening of the main fuel channel is located at the sleeve smoke inlet of the main fuel sleeve.

[0012] Furthermore, the opening area of ​​the sleeve smoke inlet opened on each main fuel sleeve accounts for 30%-70% of the surface area of ​​the main fuel sleeve.

[0013] Furthermore, the ratio of the cross-sectional area of ​​the main fuel sleeve to the inlet section of the main fuel channel is between 2-4.

[0014] Furthermore, the central fuel channel, the air channel, the main fuel channel and the main fuel sleeve are all made of high temperature resistant materials.

[0015] Compared with the prior art, the present invention has the following effects:

[0016] The main fuel of the present invention is input through a plurality of main fuel channels, which can increase the uniformity of the main flame, reduce the flame temperature, and thus reduce the generation of thermal nitrogen oxides;

[0017] The main fuel channel of the present invention is provided with a main fuel channel conical opening at the end thereof, which can draw high-temperature smoke into the main fuel channel under the action of a high-speed jet, dilute the gas fuel concentration, and further reduce the flame temperature, thereby controlling the generation of thermal nitrogen oxides;

[0018] The fuel of the present invention is supplied in two stages through a central fuel channel and a plurality of main fuel channels, which can not only realize fuel staged combustion, avoid concentrated fuel combustion and thus control the generation of nitrogen oxides, but also increase flame stability;

[0019] The main fuel channel of the present invention converges toward the center, which is beneficial to the mixing of fuel gas and air and can increase the stability of the flame. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 A cross-sectional view of the nozzle of a main flame convergent low NOx burner;

[0022] Figure 2 A schematic diagram of the position relationship of the nozzle of the main flame convergence type low nitrogen oxide burner in the side view direction;

[0023] Figure 3 A schematic diagram of the three-dimensional structure of the nozzle of the main flame focusing low nitrogen oxide burner;

[0024] In the figure, 1 is the central fuel channel; 2 is the air channel; 3 is the main fuel channel; 3-1 is the inlet section of the main fuel channel; 3-2 is the tapered mouth of the main fuel channel; 4 is the main fuel sleeve; 4-1 is the sleeve smoke inlet; 5 is the furnace body. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0026] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] Referring to the accompanying drawings, this embodiment is described. A main flame convergent low nitrogen oxide burner nozzle includes a central fuel pipeline 1, an air channel 2, a plurality of main fuel channels 3 and a plurality of main fuel sleeves 4. The air channel 2 is coaxially sleeved on the outside of the central fuel channel 1. A plurality of main fuel channels 3 are evenly distributed circumferentially on the outside of the air channel 2. The main fuel channels 3 are in a furnace body 5. The head end of the main fuel channel 3 is a main fuel channel inlet section 3-1, which is fixed to the furnace body 5. The end of the main fuel channel 3 is a main fuel channel tapered opening 3-2. The main fuel sleeve 4 is sleeved on the corresponding main fuel channel tapered opening 3-2. The main fuel channel inlet section 3-1, the main fuel channel tapered opening 3-2 and the main fuel sleeve 4 gradually converge toward the central fuel channel 1 along the same axis in the furnace body. Each main fuel sleeve 4 has a plurality of sleeve smoke inlets 4-1 circumferentially.

[0028] The main fuel of the present invention is input through a plurality of main fuel channels 3, which can increase the uniformity of the main flame, avoid the phenomenon of excessive flame temperature due to concentrated combustion of fuel, and thus reduce the generation of thermal nitrogen oxides; the main fuel channel conical mouth arranged in the main fuel channel 3 of the present invention is a high-speed nozzle, which draws high-temperature flue gas into the main fuel channel 3 under the action of the high-speed jet, which can dilute the concentration of the gas fuel, thereby reducing the flame temperature and controlling the generation of thermal nitrogen oxides; the fuel of the present invention is supplied in two stages through the central fuel channel 1 and a plurality of main fuel channels 3, which can realize staged combustion of fuel, control the generation of nitrogen oxides, and also increase flame stability; the main fuel channel 3 of the present invention gathers toward the center close to the air channel 2, which is beneficial to the mixing of gas and air and can increase the stability of the flame.

[0029] The main fuel channel 3 and the main fuel sleeve 4 are on the same axis and maintain an angle of 10-20° with the axis of the central fuel channel 1. Specifically, it is the angle at A. If the angle between the main fuel channel 3 and the central fuel channel 1 is too small, the mutual support between the flames cannot be guaranteed, thereby reducing the stable combustion ability of the burner. By controlling the angle between the axis of the main fuel channel 3 and the axis of the central fuel channel 1 within the range of 10°-20° to ensure sufficient flame length, it is avoided that the concentration of flames causes excessive nitrogen oxide emissions and burning nozzles, thereby reducing the generation of thermal nitrogen oxides;

[0030] The air channel 2 and the main fuel channel 3 are fixedly connected to the furnace wall of the furnace body 5. Preferably, the air channel 2 and the main fuel channel 3 are fixedly connected to the furnace wall through flanges, the furnace wall supports the main fuel channel 3 and the air channel 2, and the flanges ensure the inclination angle of the main fuel channel.

[0031] The number of the main fuel channels 3 is 3-16. Specifically, the main fuel channels 3 are arranged in a multi-channel form, and the multiple main fuel channels 3 are evenly distributed around the air channel 2. If the main fuel channels 3 are less than 3, the flame cannot be dispersed, and the purpose of reducing the flame temperature cannot be achieved; if the main fuel channels 3 are more than 16, the momentum of the fuel in a single channel is reduced, the flame length is affected, and then the temperature distribution of the entire furnace is affected, the uniformity of the main flame is increased, and the concentrated combustion of the fuel is avoided, so that the flame temperature can be reduced, thereby reducing the generation of thermal nitrogen oxides.

[0032] The minimum distance between the outer wall of the main fuel sleeve 4 and the outer wall of the air channel 2 does not exceed the outer diameter of the main fuel sleeve 4. By limiting the distance between the main fuel sleeve 4 and the air channel 2, it can be ensured that sufficient air is replenished in the main fuel channel 3 in time during the fuel combustion process, so as to achieve the purpose of stable combustion of the fuel in the main fuel channel 3.

[0033] The main fuel channel tapered opening 3-2 is located at the sleeve smoke inlet 4-1 of the main fuel sleeve 4. When the fuel passes through the main fuel channel tapered opening 3-2, it will be ejected at high speed. By arranging the sleeve smoke inlet 4-1 after the main fuel channel tapered opening, a better high-speed fuel injection effect can be obtained, and more smoke can be sucked into the fuel, thereby diluting the fuel concentration, reducing the flame temperature, and thus reducing the generation of thermal nitrogen oxides.

[0034] The opening area of ​​the sleeve smoke inlet 4-1 opened on each main fuel sleeve 4 accounts for 30%-70% of the surface area of ​​the main fuel sleeve 4. The 30%-70% opening area on the sleeve smoke inlet 4-1 can ensure the strength of the tube wall and also ensure that the smoke has sufficient entrainment area, thereby diluting the fuel concentration, reducing the flame temperature, and thus reducing the generation of thermal nitrogen oxides.

[0035] The ratio of the cross-sectional area of ​​the main fuel sleeve 4 to the main fuel channel inlet section 3-1 is between 2 and 4. A large cross-sectional area will reduce the fuel outlet velocity and cause sleeve burning; a small cross-sectional area will affect the amount of entrained smoke and the dilution effect of smoke on fuel.

[0036] The central fuel channel 1, the air channel 2, the main fuel channel 3 and the main fuel sleeve 4 are all made of high temperature resistant materials. Preferably, the high temperature resistant material is 316 stainless steel or the like.

[0037] Obviously, the embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to specific implementation methods. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. It is not necessary and impossible to exhaustively list all implementation methods here.

Claims

1. A main flame convergence type low nitrogen oxide burner nozzle, characterized in that: The invention comprises a central fuel pipeline (1), an air channel (2), a plurality of main fuel channels (3) and a plurality of main fuel sleeves (4); the air channel (2) is coaxially sleeved on the outside of the central fuel channel (1); a plurality of main fuel channels (3) are evenly distributed circumferentially on the outside of the air channel (2); the main fuel channels (3) are located in a furnace body (5); the head end of the main fuel channel (3) is a main fuel channel inlet section (3-1); the main fuel channel inlet section (3-1) is fixedly connected to the furnace body (5); the end of the main fuel channel (3) is a main fuel channel conical opening (3-2); the main fuel sleeve (4) is sleeved on the corresponding main fuel channel conical opening (3-2); the main fuel channel inlet section (3-1), the main fuel channel conical opening (3-2) and the main fuel sleeve (4) gradually converge toward the central fuel channel (1) along the same axis in the furnace body; each main fuel sleeve (4) is provided with a plurality of sleeve smoke inlets (4-1) along the circumferential direction.

2. The main flame convergence type low nitrogen oxide burner nozzle according to claim 1, characterized in that: The main fuel channel (3) and the main fuel sleeve (4) are located on the same axis and maintain an angle of 10-20° with the axis of the central fuel channel (1).

3. The main flame convergence type low nitrogen oxide burner nozzle according to claim 1, characterized in that: The air channel (2) and the main fuel channel (3) are fixedly connected to the furnace wall of the furnace body (5).

4. The main flame convergence type low nitrogen oxide burner nozzle according to claim 1, characterized in that: The number of the main fuel channels (3) is 3-16.

5. The main flame convergence type low nitrogen oxide burner nozzle according to claim 1, characterized in that: The minimum distance between the outer wall of the main fuel sleeve (4) and the outer wall of the air passage (2) does not exceed the outer diameter of the main fuel sleeve (4).

6. The main flame convergence type low nitrogen oxide burner nozzle according to claim 1, characterized in that: The tapered opening (3-2) of the main fuel channel is located at the sleeve smoke inlet (4-1) of the main fuel sleeve (4).

7. The main flame convergence type low nitrogen oxide burner nozzle according to claim 1, characterized in that: The opening area of ​​the sleeve smoke inlet (4-1) opened on each main fuel sleeve (4) accounts for 30%-70% of the surface area of ​​the main fuel sleeve (4).

8. The main flame convergence type low nitrogen oxide burner nozzle according to claim 1, characterized in that: The ratio of the cross-sectional area of ​​the main fuel sleeve (4) to the main fuel channel inlet section (3-1) is between 2 and 4.

9. The main flame convergence type low nitrogen oxide burner nozzle according to claim 1, characterized in that: The central fuel channel (1), the air channel (2), the main fuel channel (3) and the main fuel sleeve (4) are all made of high temperature resistant materials.

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