A flue gas recirculation type swirl natural gas burner

Abstract

The present invention relates to the field of burners, and particularly to a flue gas recirculation type swirl natural gas burner. It mainly solves the problem that the nitrogen oxide emissions of existing gas burners are relatively high and cannot meet the emission requirements. A recirculation flue gas pipeline (13) and an auxiliary air pipeline (15) are connected to the air duct housing (4). An outer auxiliary air sleeve (1) is arranged inside the air duct housing (4). An inner auxiliary air sleeve (6) is arranged inside the outer auxiliary air sleeve (1). A plurality of main torch nozzles (2) are arranged in the annular cavity between the two. A pilot flame nozzle (7) and a spark igniter (9) are arranged inside the inner auxiliary air sleeve (6). Outer auxiliary air sleeve swirl vanes (3) are arranged on the inner wall of the outer auxiliary air sleeve (1). Inner auxiliary air sleeve swirl vanes (5) are arranged on the inner wall of the inner auxiliary air sleeve (6). This flue gas recirculation type swirl natural gas burner can reduce the generation of nitrogen oxides during combustion and solve the problem of high pollutant emissions of the burner.

Description

Technical Field

[0001] The present invention relates to the field of burners, and more specifically to a flue gas recirculation type swirl natural gas burner. Background Art

[0002] Even though natural gas is an economical and clean fossil fuel, the nitrogen oxides generated during the combustion process cannot be ignored. Nitrogen oxides (NOx) are one of the main pollutants in the atmosphere, having many adverse effects on the atmospheric environment, and the NOx emissions need to gradually approach the world's environmental protection standards. NOx has become a key target for pollution reduction in China.

[0003] Since the research on gas burners in China is relatively scarce, and the attention to NOx emissions is relatively late, the current low-nitrogen combustion technology in China is not yet mature. Low-nitrogen gas burners rely too much on foreign imports and are too expensive. Currently, the NOx emissions of domestic natural gas burners are relatively high and cannot meet the increasingly stringent domestic emission requirements. Therefore, it is necessary to develop a gas burner with low pollutant emissions. Summary of the Invention

[0004] In order to overcome the deficiency that the existing gas burners have relatively high nitrogen oxide emissions and cannot meet the emission requirements, the present invention provides a flue gas recirculation type swirl natural gas burner, which can reduce the generation of nitrogen oxides during the combustion process and solve the problem of high pollutant emissions of the burner.

[0005] The technical solution of the present invention is: a flue gas recirculation type swirl natural gas burner, including a duct housing fixed on the outer surface of the furnace. A recirculated flue gas pipe and an auxiliary air pipe are connected to the duct housing. An outer auxiliary air sleeve is provided inside the duct housing. Air inlet holes are formed on the side wall of the outer auxiliary air sleeve. An inner auxiliary air sleeve is provided inside the outer auxiliary air sleeve. A plurality of main torch nozzles are arranged in the annular cavity between the outer auxiliary air sleeve and the inner auxiliary air sleeve. A pilot flame nozzle and an igniter are provided inside the inner auxiliary air sleeve. Outer auxiliary air sleeve swirl vanes are provided on the inner wall of the outer auxiliary air sleeve, and inner auxiliary air sleeve swirl vanes are provided on the inner wall of the inner auxiliary air sleeve.

[0006] The outer auxiliary air sleeve is provided with a flanging that opens outward at the edge inside the furnace.

[0007] The number of the outer auxiliary air sleeve swirl vanes is 12 to 24, evenly distributed along the circumferential direction, and the angle between the outer auxiliary air sleeve swirl vanes and the axial direction of the inner wall of the outer auxiliary air sleeve is adjusted between 30° and 60°.

[0008] An outer swirl vane adjusting handle is connected to the outer auxiliary air sleeve swirl vanes, and the end of the outer swirl vane adjusting handle extends outside the duct housing.

[0009] The number of the internal auxiliary air sleeve swirl vanes is 12 to 18, and the angle between the internal auxiliary air sleeve swirl vanes and the inner wall of the internal auxiliary air sleeve in the axial direction is 45°.

[0010] One end of the main torch nozzle located outside the furnace is connected through an annular gas supply pipeline, and the gas supply pipeline is connected to the main gas supply pipeline of the burner.

[0011] One end of the recirculating flue gas pipeline is connected to the air duct housing, and the other end is connected to the furnace flue gas outlet, and a circulation fan is provided on the recirculating flue gas pipeline.

[0012] An adjusting baffle is provided inside one end of the recirculating flue gas pipeline connected to the air duct housing, and a flue gas shut-off baffle is provided inside the other end of the recirculating flue gas pipeline connected to the furnace flue gas outlet.

[0013] A flame monitoring device is provided outside the air duct housing.

[0014] An adjustable baffle is provided inside the auxiliary air pipeline.

[0015] The present invention has the following beneficial effects: Due to the adoption of the above solutions, through the swirling combustion of the long-lasting flame, the tangential combustion of the main torch flame, and the inner and outer auxiliary combustion air cylinders with swirling vanes, the combustion process of natural gas is classified multiple times and burned evenly, avoiding the large-scale appearance of local high-temperature zones, thereby reducing the generation of thermal-type nitrogen oxides during the combustion process; at the same time, the recirculating cold flue gas provided by the flue gas circulation fan is evenly mixed into the combustion-supporting air of the burner through the air distribution structure, thereby reducing the oxygen content per unit volume of the combustion-supporting air to a certain extent and creating an oxygen-deficient environment for the combustion process of natural gas; in addition, the incorporation of the recirculating flue gas, on the one hand, acts as an endothermic medium for the flame in the furnace, and on the other hand, improves the fullness of the hot flue gas in the furnace, making the temperature in the furnace more uniform. Through the above measures, the generation of nitrogen oxides during the operation process is greatly reduced, and the problem of high pollutant emissions of this type of burner is solved. Brief Description of the Drawings

[0016] Figure 1 is the front view of the present invention;

[0017] Figure 2 is the left view of the present invention;

[0018] Figure 3 is Figure 1 the enlarged view of I in

[0019] Figure 4 is the schematic diagram of the outer auxiliary air sleeve swirl vanes.

[0020] In the figure: 1 - outer auxiliary air sleeve, 2 - main torch nozzle, 3 - swirl vane of outer auxiliary air casing, 4 - air duct housing, 5 - swirl vane of inner auxiliary air casing, 6 - inner auxiliary air sleeve, 7 - pilot flame nozzle, 8 - gas supply pipeline, 9 - igniter, 10 - flame monitoring device, 11 - circulation fan, 12 - regulating baffle, 13 - recirculated flue gas pipeline, 14 - flue gas shut-off baffle, 15 - auxiliary air pipeline, 16 - regulating handle of outer swirl vane. Detailed implementation mode

[0021] The present invention will be described in detail below with reference to the accompanying drawings and embodiments. The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] As Figures 1 to 4 shown, a swirl natural gas burner with flue gas recirculation includes an air duct housing 4 fixed on the outer surface of the furnace. The air duct housing 4 is connected with a recirculated flue gas pipeline 13 and an auxiliary air pipeline 15. One end of the recirculated flue gas pipeline 13 is connected to the air duct housing 4, and the other end is connected to the flue gas outlet of the furnace. A circulation fan 11 is provided on the recirculated flue gas pipeline 13, and the circulation fan 11 can make the flue gas circulate between the furnace and the air duct housing 4. An adjusting baffle 12 is provided inside the end of the recirculated flue gas pipeline 13 connected to the air duct housing 4 to adjust the size of the air duct opening, thereby adjusting the air intake. A flue gas shut-off baffle 14 is provided inside the end of the recirculated flue gas pipeline 13 connected to the flue gas outlet of the furnace. A baffle for adjusting the air volume is also provided inside the auxiliary air pipeline 15 to adjust the air intake and play a role in assisting combustion.

[0023] An outer auxiliary air sleeve 1 is provided inside the air duct housing 4. The outer end of the outer auxiliary air sleeve 1 is fixed on the air duct housing 4, and the inner end is located inside the furnace. An air inlet hole is provided on the side wall of the outer auxiliary air sleeve 1 located outside the furnace, so that the flue gas entering from the recirculated flue gas pipeline 13 can enter the inside of the outer auxiliary air sleeve 1. A flanging that opens outward is provided at the edge of the outer auxiliary air sleeve 1 located inside the furnace, and the flanging can make the flue gas diffuse, so as to burn better.

[0024] On the inner wall of the outer auxiliary air sleeve 1, there are outer auxiliary air sleeve swirl vanes 3. The number of the outer auxiliary air sleeve swirl vanes 3 is 12 to 24, evenly distributed along the circumferential direction. The angle of the outer auxiliary air sleeve swirl vanes 3 is adjustable. The angle between the outer auxiliary air sleeve swirl vanes 3 and the inner wall of the outer auxiliary air sleeve 1 in the axial direction is adjusted between 30° and 60°. By adjusting the angle of the swirl vanes, the swirl intensity of the outer auxiliary air is adjusted, thereby adjusting the length of the gas flame. An outer swirl vane adjusting handle 16 is connected to the outer auxiliary air sleeve swirl vanes 3, and the end of the outer swirl vane adjusting handle 16 extends outside the air duct housing 4. The angle of the outer auxiliary air sleeve swirl vanes 3 can be adjusted by rotating the outer swirl vane adjusting handle 16.

[0025] Inside the outer auxiliary air sleeve 1, there is an inner auxiliary air sleeve 6. An annular cavity is formed between them. Inside the annular cavity, there are several main torch nozzles 2 arranged along the circumferential direction. One end of the main torch nozzle 2 located outside the furnace is connected by an annular gas supply pipeline 8. The gas supply pipeline 8 is connected to the main gas supply pipeline of the burner to supply the gas required by the main torch nozzle 2. Nozzles are opened on the side wall of the main torch nozzle 2. The jet angle of the nozzle forms a tangential jet with an angle of 10° with the axis of the main torch pipe. On the inner wall of the inner auxiliary air sleeve 6, there are inner auxiliary air sleeve swirl vanes 5. The number of the inner auxiliary air sleeve swirl vanes 5 is 12 to 18. The angle between the inner auxiliary air sleeve swirl vanes 5 and the inner wall of the inner auxiliary air sleeve 6 in the axial direction is 45°, so that the auxiliary air has a certain swirl intensity, thereby achieving the effect of stable combustion of the inner ring flame. Inside the inner auxiliary air sleeve 6, there are a pilot flame nozzle 7 and an igniter 9. A number of holes are evenly opened in the circumferential direction of the pilot flame nozzle 7. The igniter 9 is used for igniting the burner. Outside the air duct housing 4, there is a flame monitoring device 10 for monitoring the ignition state of the device.

[0026] The pilot flame nozzle 7 is ignited by the igniter 9, and the pilot flame ignites the main torch nozzle 2. The mixed air of the auxiliary air and the recirculated flue gas is gradually distributed to the combustion positions of the pilot flame nozzle 7 and the main torch nozzle 2 through the air duct housing 4, the outer auxiliary air sleeve 1, the outer auxiliary air sleeve swirl vanes 3, the inner auxiliary air sleeve 6 and the inner auxiliary air sleeve swirl vanes 5. During this process, the circulation fan 11 is started, and the flue gas in the furnace is transported to the flue gas inlet of the air duct housing 4 through the recirculated flue gas pipeline 13 for recirculation, and the air intake is adjusted by adjusting the baffle 12 to make the flue gas burn fully.

[0027] The burner forms tangential combustion through the swirling combustion of the pilot flame, the swirling vanes with adjustable swirling intensity, and the nozzles on the main torch nozzle, the inner auxiliary air sleeve, and the outer auxiliary air sleeve, which divides the combustion process of natural gas into multiple stages, enabling uniform combustion and avoiding the large-scale emergence of local high-temperature zones, thereby reducing the generation of thermal NOx during the combustion process. The recirculated cold flue gas provided by the off-furnace flue gas circulation fan is evenly mixed into the combustion-supporting air of the burner through the air distribution structure, thus reducing the oxygen content per unit volume of the combustion-supporting air to a certain extent and artificially creating an oxygen-deficient environment for the natural gas combustion process. In addition, the incorporation of the recirculated flue gas acts as an endothermic medium for the flame in the furnace on the one hand, and on the other hand, it improves the fullness of the hot flue gas in the furnace to a certain extent, making the furnace temperature more uniform. Through the above measures, the generation of NOx during operation is greatly reduced, solving the problem of high pollutant emissions of this type of burner.

[0028] The various embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to technologies in the market, or to enable other ordinary skilled persons in the art to understand the disclosed embodiments.

Claims

1. A flue gas circulation type swirl natural gas burner, comprising an air duct housing (4), the air duct housing (4) being fixed to the outer surface of a furnace, characterized in that: The air duct shell (4) is connected to a recirculating flue gas duct (13) and an auxiliary air duct (15); an outer auxiliary air sleeve (1) is provided inside the air duct shell (4); an air inlet hole is provided on a side wall of the outer auxiliary air sleeve (1); an inner auxiliary air sleeve (6) is provided inside the outer auxiliary air sleeve (1); a plurality of main flare nozzles (2) are provided in an annular cavity between the outer auxiliary air sleeve (1) and the inner auxiliary air sleeve (6); a permanent flame nozzle (7) and an ignition gun (9) are provided inside the inner auxiliary air sleeve (6); an outer auxiliary air sleeve swirl sheet (3) is provided on the inner wall of the outer auxiliary air sleeve (1); and an inner auxiliary air sleeve swirl sheet (5) is provided on the inner wall of the inner auxiliary air sleeve (6); The number of the outer auxiliary wind sleeve swirl blades (3) is 12 to 24, which are evenly distributed along the circumferential direction, and the angle between the outer auxiliary wind sleeve swirl blades (3) and the inner wall of the outer auxiliary wind sleeve (1) is adjusted between 30 and 60 degrees; the outer auxiliary wind sleeve swirl blades (3) are connected to the outer swirl blade adjustment handle (16), and the end of the outer swirl blade adjustment handle (16) extends out of the air duct housing (4); The outer auxiliary air sleeve (1) is provided with an outwardly opened folded edge at the edge located inside the furnace; The number of the inner auxiliary wind sleeve swirl blades (5) is 12 to 18, and the axial angle between the inner auxiliary wind sleeve swirl blades (5) and the inner wall of the inner auxiliary wind sleeve (6) is 45°.

2. The flue gas circulation swirl natural gas burner according to claim 1 is characterized in that: One end of the main flare nozzle (2) located outside the furnace is connected via an annular gas supply pipeline (8), and the gas supply pipeline (8) is connected to the main gas supply pipeline of the burner.

3. The flue gas circulation swirl natural gas burner according to claim 2 is characterized in that: One end of the recirculating flue gas duct (13) is connected to the air duct housing (4), and the other end is connected to the furnace flue gas outlet, and a circulating fan (11) is provided on the recirculating flue gas duct (13).

4. The flue gas circulation swirl natural gas burner according to claim 3 is characterized in that: An adjusting damper (12) is provided inside the end of the recirculating flue gas duct (13) connected to the air duct housing (4), and a flue gas shut-off damper (14) is provided inside the end of the recirculating flue gas duct (13) connected to the furnace flue gas outlet.

5. The flue gas circulation swirl natural gas burner according to claim 4 is characterized in that: A flame monitoring device (10) is provided outside the air duct housing (4).

6. The flue gas circulation swirl natural gas burner according to claim 5 is characterized in that: An adjustable baffle is provided inside the auxiliary air duct (15).

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