Low-nitrogen fuel burner

Abstract

The present application relates to the technical field of combustor, and discloses a low-nitrogen oil combustor, the inner wall of the shell is fixed with an annular air duct, a plurality of first fuel oil lances are fixedly inserted on one side of the annular air duct, and the shell is provided with a closed section at one end; the inner side of the shell is provided with a central air duct located on the inner side of the annular air duct; the combustion flue gas of the first fuel oil lance is induced to enter the inner side of the annular frame through the negative pressure generated when the medium flows through the closed section; the recirculated flue gas is mixed with the high-speed medium flow in the central air duct, the combustion temperature is reduced, the generation of thermal nitrogen oxides is reduced, the air entering the central air duct is lower than the required air amount for the combustion of the second fuel oil lance, an oxygen-deficient state is formed, the air amount of the annular air duct is higher than the required air amount for the combustion of the first fuel oil lance, the center of the combustion flame is controlled to be in an oxygen-deficient state, the generation of nitrogen oxides is further reduced, the generation of thermal nitrogen oxides during the combustion of fuel oil is reduced, and low-nitrogen combustion of fuel oil is realized.

Description

Technical Field

[0001] This invention relates to the field of burner technology, specifically to low-NOx fuel oil burners. Background Technology

[0002] A burner is a general term for a device that sprays fuel and air in a specific manner for combustion. Burners are classified into several types based on their application: industrial burners, combustion engines, civil burners, and special burners. They are mostly made of corrosion-resistant and high-temperature-resistant materials such as stainless steel or titanium. The function of a burner is to atomize a sample through flame combustion. The atomized sample enters the burner, and under the influence of the flame temperature and atmosphere, undergoes processes such as drying, melting, evaporation, and dissociation, producing a large number of ground-state atoms, as well as some excited-state atoms, ions, and molecules.

[0003] Existing fuel nozzle atomization methods mainly include mechanical atomization and pneumatic atomization. Mechanical atomization uses a high-pressure system to spray fuel from the nozzle at high speed. During the spraying process, a velocity difference is created between the fuel and the surrounding air, or the fuel directly impacts a specific object. The shearing or impact force generated by the velocity difference breaks the fuel into tiny droplets. Pneumatic atomization uses a high-speed airflow to impact the fuel column or film. The powerful energy of the high-speed airflow causes the fuel column or film to break up, forming tiny fuel droplets.

[0004] Regardless of whether mechanical or pneumatic atomization is used, liquid fuel is sprayed out at the fuel nozzle outlet in an umbrella-shaped structure at a specific angle. Subsequently, these sprayed fuel droplets mix with combustion air, leading to a combustion reaction. In traditional fuel nozzle structures, because the fuel is sprayed in an umbrella-shaped structure, the fuel accumulates highly in the area near the nozzle outlet, resulting in a high-temperature convergence zone during combustion. Under high-temperature conditions, the nitrogen in the fuel reacts violently with the oxygen in the air, generating a large amount of thermal nitrogen oxides. Therefore, a low-NOx fuel burner has been proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a low-NOx fuel burner to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a low-NOx fuel burner, comprising a housing, an annular air duct fixed to the inner wall of the housing, a plurality of first fuel injection guns fixedly inserted into one side of the annular air duct, and a tapering section provided at one end of the housing; The inner side of the housing is provided with a central air duct located inside the annular air duct, and a second fuel injection gun is fixedly inserted into one side of the central air duct. The lower side of the housing is provided with an air volume regulating component, and the second fuel injection gun is provided with a mixing component on one side. The air volume regulating component includes a housing, with a circulating flue gas inlet and an air inlet on the outside of the housing, and a first air outlet and a second air outlet on the top of the housing. The inner walls of the first air outlet and the second air outlet are rotatably connected to baffles via a rotating shaft. The mixing component includes an annular frame, with a through groove on one side of the annular frame, and a number of swirl vanes fixed to the inner wall of the through groove.

[0007] Preferably, the first fuel injector has a flame stabilizer plate fixed to its outer side, the flame stabilizer plate has several through holes on its surface, and the inclination angle between the flame stabilizer plate and the housing is 14°-16°.

[0008] Preferably, the first fuel injector has a first fuel inlet at one end and a second air outlet connected to an annular air duct.

[0009] Preferably, the second fuel injector is provided with a compressed air inlet and a fuel inlet at one end, and the first air outlet is connected to the central air duct.

[0010] Preferably, the housing is fixed to one side of the shell, an actuator is fixed to one side of the housing, and the output end of the actuator is fixed to the end of the rotating shaft of the baffle.

[0011] Preferably, the inner wall of the ring frame is fixed with a plurality of connecting blocks, one side of which is fixed to the outer side of the closing section.

[0012] Preferably, the angle between the swirling vane and the annular frame is 44°-46°, and the swirling vane is used to form a strong swirling mixing field.

[0013] Preferably, one end of the constriction section is located inside the annular frame, and the second fuel injector is located at the center of the central air duct.

[0014] Preferably, a negative pressure suction channel is formed between adjacent connecting blocks. When the medium flows through the constriction section, a negative pressure is generated at the negative pressure suction channel, inducing the combustion flue gas from the first fuel injector to enter the inner side of the annular frame for mixing.

[0015] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects: First, by coordinating the combustion of the first and second fuel injectors with the annular and central air ducts respectively, the precise supply of combustion air is achieved, improving the mixing effect of fuel and combustion air. Low-oxygen circulating flue gas is introduced through the circulating flue gas inlet, and combustion air is introduced through the air inlet. By adjusting the baffle opening, the amount of combustion air entering the annular and central air ducts can be precisely controlled, thereby regulating the oxygen concentration in the combustion zone, further optimizing the combustion process, and thus improving combustion efficiency.

[0016] Second, the negative pressure generated by the medium flowing through the converging section induces the combustion flue gas from the first fuel injector to enter the inner side of the annular frame. The recirculated flue gas mixes with the high-speed medium flow in the central air duct, reducing the combustion temperature and thus reducing the generation of thermal nitrogen oxides. The air entering the central air duct is lower than the air required for combustion of the central second fuel injector, creating an oxygen-deficient state. Furthermore, the air volume in the annular air duct is higher than the air volume required for combustion of the peripheral first fuel injector, controlling the center of the combustion flame to be in an oxygen-deficient state, further reducing the generation of nitrogen oxides. This reduces the generation of thermal nitrogen oxides during fuel combustion, achieving low-NOx combustion of fuel. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the front cross-sectional structure of the present invention; Figure 2 This is a schematic diagram of the main structure of the present invention; Figure 3 This is a schematic diagram of the structure at the swirl vane of the present invention; Figure 4 This is a schematic diagram of the angle structure of the flame stabilizer disk in this invention.

[0019] Explanation of reference numerals in the attached drawings: 1. Housing; 2. Central air duct; 3. First fuel injector; 31. First fuel inlet; 32. Flame stabilizer; 33. Through hole; 4. Second fuel injector; 41. Compressed air inlet; 42. Second fuel inlet; 5. Air volume adjustment component; 51. Circulating flue gas inlet; 52. Air inlet; 53. Baffle; 54. Actuator; 55. First exhaust end; 56. Second exhaust end; 57. Housing; 6. Mixing component; 61. Swirl vane; 62. Connecting block; 63. Through groove; 64. Annular frame; 7. Annular air duct; 8. Closing section. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce. Example

[0022] Please see Figure 1-4 This invention provides a technical solution: a low-NOx fuel burner, comprising a housing 1, an annular air duct 7 fixed to the inner wall of the housing 1, and a plurality of first fuel spray guns 3 fixedly inserted into one side of the annular air duct 7. The first fuel spray guns 3 are evenly distributed along the annular air duct 7 and spray fuel into the outer combustion zone through mechanical atomization. One end of the housing 1 is provided with a constriction section 8. A central air duct 2 located inside the annular air duct 7 is provided on the inner side of the housing 1, and a second fuel spray gun 4 is fixedly inserted into one side of the central air duct 2. The second fuel spray gun 4 is located at the axis of the central air duct 2 and sprays fuel into the central combustion zone through compressed air atomization. The first fuel spray guns 3 and the second fuel spray gun 4 are responsible for different combustion zones, realizing the staged input of fuel, which helps to more precisely control the combustion process and improve the combustion effect. An airflow regulating component 5 is provided on the lower side of the housing 1, and a mixing component 6 is provided on one side of the second fuel spray gun 4. A flame stabilizer plate 32 is fixed to the outside of the first fuel injector 3. The surface of the flame stabilizer plate 32 has several through holes 33. The inclination angle between the flame stabilizer plate 32 and the housing 1 is 15°. The through holes 33 on the surface of the flame stabilizer plate 32 form a stable individual flame, which effectively prevents the flame from going out and enhances the stability of combustion. The distribution of multiple first fuel injectors 3 reduces the concentration of fuel flame and reduces the local high temperature zone of the flame, which helps to reduce the generation of thermal nitrogen oxides and extend the service life of the burner. The annular air duct 7 is located on the inner wall of the housing 1 and provides combustion air to the first fuel injectors 3. The number of first fuel injectors 3 is preferably four.

[0023] The air volume regulating component 5 includes a housing 57. The outer side of the housing 57 is provided with a circulating flue gas inlet 51 and an air inlet 52. The circulating flue gas inlet 51 introduces low-oxygen circulating flue gas to reduce the combustion temperature and oxygen concentration. The air inlet 52 introduces combustion air, which is mixed with the flue gas and then distributed to the annular air duct 7 and the central air duct 2. The top of the housing 57 is provided with a first air outlet 55 and a second air outlet 56. The inner walls of the first air outlet 55 and the second air outlet 56 are rotatably connected to baffles 53 via a rotating shaft. The opening of the baffles 53 is adjusted by the actuator 54 to control the amount of mixed gas entering the annular air duct 7 and the central air duct 2, thereby regulating the oxygen concentration in the combustion zone.

[0024] The housing 57 is fixed to one side of the housing 1. An actuator 54 is fixed to one side of the housing 57. Two actuators 54 are installed. The output end of the actuator 54 is fixed to the end of the rotating shaft of the baffle 53.

[0025] The first fuel injector 3 has a first fuel inlet 31 at one end and a second air outlet 56 connected to the annular air duct 7 at the other end. The second fuel injector 4 has a compressed air inlet 41 and a second fuel inlet 42 at one end and a first air outlet 55 connected to the central air duct 2. Fuel enters through the second fuel inlet 42 and compressed air enters through the compressed air inlet 41, forming a high-speed medium flow and generating a strong swirling mixing field, which further enhances the mixing of fuel and combustion air and improves combustion efficiency.

[0026] The mixing component 6 includes an annular frame 64, with a through groove 63 on one side of the annular frame 64. Several swirl vanes 61 are fixed to the inner wall of the through groove 63, and several connecting blocks 62 are fixed to the inner wall of the annular frame 64. One side of the connecting block 62 is fixed to the outer side of the constriction section 8. The angle between the swirl vanes 61 and the annular frame 64 is 45°. The swirl vanes 61 are used to form a strong swirling mixing field. The strong swirling mixing field formed by the swirl vanes 61 enhances the mixing of fuel and combustion air, improves combustion efficiency, and reduces the generation of incomplete combustion products.

[0027] One end of the constriction section 8 is located inside the annular frame 64, and the second fuel injector 4 is located at the axis of the central air duct 2. A negative pressure suction channel is formed between adjacent connecting blocks 62. When the medium flows through the constriction section 8, a negative pressure is generated at the negative pressure suction channel, which induces the combustion flue gas of the first fuel injector 3 to enter the inner side of the annular frame 64 for mixing.

[0028] Working principle: The annular air duct 7 is located on the inner wall of the housing 1. Combustion air is introduced through the second air outlet 56 of the air volume regulating component 5 to cooperate with the combustion of the first fuel injector 3; the central air duct 2 is located inside the annular air duct 7. Combustion air is introduced through the first air outlet 55 of the air volume regulating component 5 to cooperate with the combustion of the second fuel injector 4. The first fuel spray gun 3 is fixed to one side of the annular air duct 7. It forms fine droplets through mechanical atomization and mixes with the combustion air in the annular air duct 7 for combustion. The second fuel spray gun 4 is located at the axis of the central air duct 2. It atomizes fuel through compressed air to form a high-speed medium flow and mixes with the combustion air in the central air duct 2. Low-oxygen circulating flue gas is introduced at the circulating flue gas inlet 51, and combustion air is introduced at the air inlet 52. By adjusting the opening of the baffle 53, the amount of combustion air entering the annular air duct 7 and the central air duct 2 is controlled, thereby adjusting the oxygen concentration in the combustion zone. A channel is formed between adjacent connecting blocks 62. When the medium flows through the converging section 8, a negative pressure is generated, inducing the combustion flue gas of the first fuel injector 3 to enter the inner side of the annular frame 64. The recirculated flue gas mixes with the high-speed medium flow in the central air duct 2, reducing the combustion temperature and the generation of thermal nitrogen oxides. Through holes 33 are opened on the surface of the flame stabilizer 32 to form a stable individual flame and prevent the flame from going out. Fuel enters through the second fuel inlet 42, and compressed air enters through the compressed air inlet 41, forming a high-speed medium flow and a strong swirling mixing field, which enhances the mixing of fuel and combustion air and improves combustion efficiency. The first fuel injector 3 and the second fuel injector 4 are responsible for different combustion zones, realizing the staged input of fuel. Controlled by the airflow regulating component 5, the air entering the central air duct 2 is lower than the air required for combustion of the central second fuel injector 4, creating an oxygen-deficient state. The airflow in the annular air duct 7 is higher than the air required for combustion of the peripheral first fuel injector 3, controlling the center of the combustion flame to be in an oxygen-deficient state. The distribution of multiple first fuel injectors 3 reduces the concentration of the fuel flame and reduces the local high-temperature zone of the flame. At the same time, it makes full use of the internal and external circulation of flue gas to reduce the oxygen partial pressure of the combustion air at the burner nozzle, greatly reducing the generation of thermal nitrogen oxides during fuel combustion and achieving low-NOx combustion of fuel.

[0029] In summary, by coordinating the combustion of the first fuel injector 3 and the second fuel injector 4 with the annular air duct 7 and the central air duct 2 respectively, the precise supply of combustion air is achieved, improving the mixing effect of fuel and combustion air. Low-oxygen circulating flue gas is introduced through the circulating flue gas inlet 51, and combustion air is introduced through the air inlet 52. By adjusting the opening of the baffle 53, the amount of combustion air entering the annular air duct 7 and the central air duct 2 can be precisely controlled, thereby adjusting the oxygen concentration in the combustion zone, further optimizing the combustion process, and thus improving combustion efficiency.

[0030] The negative pressure generated by the medium flowing through the converging section 8 induces the combustion flue gas of the first fuel injector 3 to enter the inner side of the annular frame 64. The recirculated flue gas mixes with the high-speed medium flow in the central air duct 2, reducing the combustion temperature and thus reducing the generation of thermal nitrogen oxides. The air entering the central air duct 2 is lower than the amount of air required for combustion of the central second fuel injector 4, creating an oxygen-deficient state. Furthermore, the air volume in the annular air duct 7 is higher than the amount of air required for combustion of the peripheral first fuel injector 3, controlling the center of the combustion flame to be in an oxygen-deficient state, further reducing the generation of nitrogen oxides. This reduces the generation of thermal nitrogen oxides during fuel combustion and achieves low-NOx combustion of fuel.

[0031] Those skilled in the art will understand that the features described in the various embodiments and / or claims of the present invention can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments and / or claims of the present invention can be combined or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or combinations fall within the scope of the present invention.

Claims

1. A low-NOx fuel burner, comprising a housing (1), characterized in that: The inner wall of the housing (1) is fixed with an annular air duct (7), and a number of first fuel injection guns (3) are fixedly inserted on one side of the annular air duct (7). One end of the housing (1) is provided with a constriction section (8). The inner side of the housing (1) is provided with a central air duct (2) located inside the annular air duct (7), and a second fuel injector (4) is fixedly inserted into one side of the central air duct (2). The housing (1) is provided with an air volume regulating component (5) on its lower side, and a mixing component (6) is provided on one side of the second fuel injector (4). The air volume regulating component (5) includes a housing (57), on the outside of the housing (57) are respectively provided a circulating flue gas inlet (51) and an air inlet (52), and on the top of the housing (57) are respectively provided a first air outlet (55) and a second air outlet (56). The inner walls of the first air outlet (55) and the second air outlet (56) are rotatably connected to baffles (53) through a rotating shaft. The mixing component (6) includes an annular frame (64), and a through groove (63) is provided on one side of the annular frame (64). A plurality of swirl vanes (61) are fixed on the inner wall of the through groove (63). The first fuel injector (3) has a flame stabilizer plate (32) fixed on its outer side. The flame stabilizer plate (32) has several through holes (33) on its surface. The inclination angle between the flame stabilizer plate (32) and the housing (1) is 14°-16°. The first fuel injector (3) has a first oil inlet (31) at one end and a second air outlet (56) connected to an annular air duct (7); The second fuel injector (4) is provided with a compressed air inlet (41) and a second fuel inlet (42) at one end, and the first air outlet (55) is connected to the central air duct (2); The housing (57) is fixed to one side of the shell (1), and an actuator (54) is fixed to one side of the housing (57). The output end of the actuator (54) is fixed to the end of the rotating shaft of the baffle (53). The inner wall of the ring frame (64) is fixed with a number of connecting blocks (62), and one side of the connecting block (62) is fixed to the outside of the closing section (8); The angle between the swirl vane (61) and the annular frame (64) is 44°-46°, and the swirl vane (61) is used to form a strong swirling mixing field; One end of the constriction section (8) is located inside the ring frame (64), and the second fuel injector (4) is located at the center of the central air duct (2).

2. The low-NOx fuel burner according to claim 1, characterized in that: A negative pressure suction channel is formed between adjacent connecting blocks (62). When the medium flows through the constriction section (8), a negative pressure is generated at the negative pressure suction channel, which induces the combustion flue gas of the first fuel injector (3) to enter the inner side of the annular frame (64) for mixing.

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