A flue gas internal circulation ultra-low pollutant emission gas combustion device

Abstract

The application discloses a flue gas internal circulation ultra-low pollutant emission gas combustion device and relates to the technical field of burners, which solves the problem of excessive initial emission of nitrogen oxides of the existing gas boiler. The main flame injection nozzle is externally sleeved with a main flame gas nozzle; a plurality of flue gas entraining holes are arranged on the main flame gas nozzle; an air channel end is provided with an air channel necking portion and extends into a gas mixing cylinder; a duty flame gas pipe end penetrates through the gas mixing cylinder and is provided with a plurality of duty flame short pipes, the duty flame short pipes are obliquely arranged, and the oblique direction is towards the main flame gas nozzle, thereby playing a stable combustion role. The high-speed fluid formed by the air channel necking portion and the main flame injection nozzle is injected through the entraining action, the flue gas in the furnace is introduced through the plurality of flue gas entraining holes, the inert gas in the combustion zone is increased, the flue gas absorbs heat and dilutes the oxygen concentration, the combustion speed and temperature are reduced, and the generation of NOx is inhibited.

Description

Technical Field

[0001] This invention relates to the field of burner technology, specifically to a flue gas internal circulation ultra-low pollutant emission gas combustion device. Background Technology

[0002] While the widespread use of gas-fired industrial boilers avoids most of the pollution caused by coal-fired boilers, they still produce NOx gas, polluting the environment. Once released into the atmosphere, NOx produces photochemical smog, ultimately leading to ozone layer depletion, the greenhouse effect, reduced crop yields, and eye and respiratory diseases in humans and animals, and in some cases, even death. Therefore, there is a need for a gas-fired burner device that can effectively control the initial NOx emissions. Summary of the Invention

[0003] To address the aforementioned problem of excessive initial nitrogen oxide emissions from existing gas-fired boilers, this invention proposes an ultra-low pollutant emission gas combustion device with internal flue gas circulation. This invention utilizes a narrowed air passage and the high-speed fluid ejection effect created by the main flame ejector nozzle to introduce flue gas into the furnace through the main flue gas inlet, rear flue gas entrainment hole, and front flue gas entrainment hole. This increases the inert gas content in the combustion zone. Because the flue gas absorbs heat and dilutes the oxygen concentration, the combustion rate and temperature decrease, thereby suppressing NOx formation.

[0004] This invention proposes a flue gas internal circulation ultra-low pollutant emission gas combustion device, which specifically includes a standby flame gas pipe, a burner air box, a main gas passage, an air passage, a boiler refractory layer transition section, several main flame gas pipes, several main flame gas nozzles, and a gas mixing cylinder. The burner air box and the air passage are connected. The main gas passage and the boiler refractory layer transition section are concentrically arranged on the outer ring of the air passage, and the main gas passage and the boiler refractory layer transition section are connected. After passing through the boiler refractory layer transition section, the air passage has an air passage narrowing at its end. Several main flame gas pipes are arranged inside the boiler refractory layer transition section. One end of the main flame gas pipe is connected to the main gas passage, and the other end passes through the boiler refractory layer transition section and has a main flame ejector nozzle at its end. The main flame ejector nozzle is fitted with a main flame gas nozzle. Several flue gas entrainment holes are arranged on the main flame gas nozzle. A gas mixing cylinder is arranged inside the several main flame gas nozzles, and the gas mixing cylinder is located in front of the narrowing of the air passage. The duty flame gas pipe passes through the center of the burner air box, air passage and gas mixing cylinder, and has several duty flame short pipes installed at the end at an angle.

[0005] Furthermore, each of the aforementioned short flame tubes for duty corresponds to one of the aforementioned main flame gas nozzles, with the short flame tubes for duty tilting towards the main flame gas nozzles.

[0006] Furthermore, the plurality of flue gas entrainment holes include a plurality of rear flue gas entrainment holes and a plurality of front flue gas entrainment holes. The plurality of rear flue gas entrainment holes are disposed on the main flame gas nozzle pipe wall on the outer periphery of the main flame ejector nozzle, and the plurality of front flue gas entrainment holes are disposed on the main flame gas nozzle pipe wall in front of the main flame ejector nozzle.

[0007] Furthermore, the width of the rear smoke entrainment hole is greater than that of the front smoke entrainment hole, and the length of the rear smoke entrainment hole is less than that of the front smoke entrainment hole.

[0008] Furthermore, the gas mixing cylinder is provided with a main flue gas inlet at one end facing the narrowing of the air channel, and a flared end at the other end.

[0009] Furthermore, the constricted end of the air passage extends into the main flue gas intake port.

[0010] Furthermore, the end of the duty flame gas pipe is also fitted with a duty sleeve, and the duty sleeve is equipped with swirl blades.

[0011] Furthermore, the duty flame short tube passes through the swirl blades.

[0012] Furthermore, the swirl blades are provided with several axial injection holes for the standby flame.

[0013] Furthermore, a main flame support plate is provided at the end of the transition section of the boiler refractory layer, which supports the air passage and several main flame gas pipes.

[0014] The beneficial effects of the flue gas internal circulation ultra-low pollutant emission gas combustion device of the present invention are as follows: (1) The flue gas internal circulation ultra-low pollutant emission gas combustion device of the present invention divides the gas into the duty flame and the main combustion stage flame by setting the duty flame gas pipe and the main flame gas delivery pipe, thereby completing the fuel classification, avoiding flame concentration and reducing local high temperature zone; (2) The flue gas internal circulation ultra-low pollutant emission gas combustion device of the present invention has a number of duty flame short pipes corresponding to a number of main flame gas nozzles, and the duty flame short pipes are inclined towards the main flame gas nozzles to play a role in stabilizing combustion. (3) The flue gas internal circulation ultra-low pollutant emission gas combustion device of the present invention introduces flue gas into the combustion device through the high-speed fluid formed by the air channel narrowing and the main flame ejector nozzle, through the main flue gas entrainment inlet, the rear flue gas entrainment hole and the front flue gas entrainment hole, thereby increasing the inert gas content in the combustion zone. Because the flue gas absorbs heat and dilutes the oxygen concentration, the combustion speed and temperature are reduced, thereby inhibiting the formation of NOx. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0016] In the attached diagram: Figure 1 This is a schematic diagram of the structure of a flue gas internal circulation ultra-low pollutant emission gas combustion device according to the present invention; Figure 2 This is a right view of a flue gas internal circulation ultra-low pollutant emission gas combustion device according to the present invention; Figure 3 This is a schematic diagram of the main flame gas nozzle of a flue gas internal circulation ultra-low pollutant emission gas combustion device according to the present invention; Among them: 1-Stationary flame gas pipe, 2-Burner air box, 3-Main flame gas delivery pipe, 4-Main gas passage, 5-Air passage, 6-Air passage constriction, 7-Boiler refractory layer transition section, 8-Main flame support plate, 9-Main flame ejector nozzle, 10-Rear flue gas entrainment hole, 11-Front flue gas entrainment hole, 12-Main flame gas nozzle, 13-Main flue gas entrainment inlet, 14-Expansion, 15-Gas mixing cylinder, 16-Stationary flame short pipe, 17-Swirl vane, 18-Stationary flame axial injection hole, 19-Main flame gas pipe, 20-Stationary sleeve. Detailed Implementation

[0017] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings: Specific implementation method one: See Figures 1-3This embodiment is described in detail. The flue gas internal circulation ultra-low pollutant emission gas combustion device described in this embodiment specifically includes a standby flame gas pipe 1, a burner air box 2, a main gas passage 4, an air passage 5, a boiler refractory layer transition section 7, several main flame gas pipes 19, several main flame gas nozzles 12, and a gas mixing cylinder 15. The burner air box 2 and the air passage 5 are connected to provide oxygen for the combustion process. The outer ring of the air passage 5 is concentrically arranged with the main gas passage 4 and the boiler refractory layer transition section 7. One end of the main gas passage 4 is connected to the burner air box 2, and the other end is connected to the boiler refractory layer transition section 7. A main flame support plate 8 is provided at the end of the boiler refractory layer transition section 7, which supports the air passage 5 and several main flame gas pipes 19. After passing through the boiler refractory layer transition section 7 and the main flame support plate 8, the air passage 5 has an air passage constriction 6 at its end, allowing air to flow from the air passage. After the gas flows out of the gas channel 5, the flow velocity increases, forming a high-speed fluid that generates an entraining effect, entraining the flue gas. Several main flame gas pipes 19 are installed inside the boiler refractory layer transition section 7. One end of the main flame gas pipe 19 is connected to the main gas channel 4, and the other end extends out of the boiler refractory layer transition section 7 and is equipped with a main flame ejector nozzle 9 at the end. Several main flame gas pipes 19 are evenly distributed on the outer ring of the air channel 5. A main flame gas nozzle 12 is sleeved on the outside of the main flame ejector nozzle 9. Several flue gas entrainment holes are provided on the main flame gas nozzle 12. The gas is injected into the main flame gas nozzle 12 through the main flame ejector nozzle 9 to increase the gas flow velocity, forming a high-speed fluid that generates an entraining effect, drawing the flue gas from the front and rear flue gas entrainment holes into the main flame gas nozzle 12. A gas mixing cylinder 15 is provided inside the several main flame gas nozzles 12, and the gas mixing cylinder 15 is located in front of the air channel constriction 6. The standby flame gas pipe 1 passes through the center of the burner wind box 2, air passage 5 and gas mixing cylinder 15, and has several standby flame short pipes 16 inclined at its end in front of the gas mixing cylinder 15. The several standby flame short pipes 16 are inclined outward from the standby flame gas pipe 1. Furthermore, the several standby flame short pipes 16 correspond one-to-one with several main flame gas nozzles 12. The inclined direction of the standby flame short pipes 16 is towards the main flame gas nozzles 12, so that the gas ejected from the standby flame short pipes 16 and the mixed gas ejected from the main flame gas nozzles 12 merge in the furnace, which plays a role in stabilizing combustion.

[0018] The plurality of flue gas entrainment holes include a plurality of rear flue gas entrainment holes 10 and a plurality of front flue gas entrainment holes 11. The plurality of rear flue gas entrainment holes 10 are disposed on the pipe wall of the main flame gas nozzle 12 in the area corresponding to the main flame ejector nozzle 9, and the plurality of front flue gas entrainment holes 11 are disposed on the pipe wall of the main flame gas nozzle 12 in front of the main flame ejector nozzle 9. When the main combustion stage gas is ejected from the main flame ejector nozzle 9, the flow velocity of the main combustion stage gas increases, becoming a high-speed fluid and generating an ejection effect, drawing the flue gas from the plurality of rear flue gas entrainment holes 10 and the plurality of front flue gas entrainment holes 11 into the main flame gas nozzle 12.

[0019] The width of the rear smoke suction hole 10 is greater than that of the front smoke suction hole 11, and the length of the rear smoke suction hole 10 is less than that of the front smoke suction hole 11.

[0020] The gas mixing cylinder 15 is provided with a main flue gas inlet 13 at one end facing the air channel constriction 6, and a flared end 14 at the other end. The end of the air channel constriction 6 extends into the main flue gas inlet 13, thereby ensuring that the air can be fully entered into the gas mixing cylinder 15 after being accelerated by the air channel constriction 6.

[0021] The end of the duty flame gas pipe 1 is also fitted with a duty sleeve 20, which is located in front of the gas mixing cylinder 15. The duty sleeve 20 has swirl vanes 17 inside. The mixture of flue gas and air rotates after passing through several swirl vanes 17, and then comes into contact with and mixes with a portion of the duty flame gas flow injected from several duty flame short pipes 16. Driven by this portion of the duty flame gas flow, it moves towards the main flame gas nozzle 12 and comes into contact with and mixes with the main combustion stage gas injected from the main flame gas nozzle 12, thus stabilizing combustion. Simultaneously, the end of the duty sleeve 20 is higher than the swirl vanes 17 and partially blocks the gas outlet of the duty flame short pipes 16, ensuring that the gas, flue gas, and air injected from the duty flame short pipes 16 are mixed to a certain extent before flowing towards the main flame gas nozzle 12.

[0022] The position where the duty flame short pipe 16 connects to the duty flame gas pipe 1 is located on one side of several swirl vanes 17, while the section at the opening of the duty flame short pipe 16 passes through several swirl vanes 17, placing it on the other side of several swirl vanes 17. The mixture of flue gas and air rotates after passing through the swirl vanes 17, while the duty gas ejected from the duty flame short pipe 16 does not rotate. This portion of the duty gas comes into full contact with the flue gas and air, further enhancing the mixing effect between the three gases.

[0023] The swirl blade 17 is provided with a plurality of axial injection holes 18 for the standby flame, and the standby flame gas pipe 1 is connected to the plurality of axial injection holes 18. Part of the standby gas ejected from the standby flame gas pipe 1 enters a plurality of standby flame short pipes 16, while the other part is directly ejected from the end of the standby flame gas pipe 1 through the plurality of axial injection holes 18 towards the front of the combustion device, providing axial momentum for the flame.

[0024] The main gas pipeline 4 is equipped with a main flame gas delivery pipe 3, which provides main combustion stage gas to the combustion device.

[0025] The specific working process of the flue gas internal circulation ultra-low pollutant emission gas combustion device of the present invention is as follows: Gas is introduced into the duty flame gas pipe 1 and the main gas pipe 4, and air is introduced into the combustion device from the burner air box 2. The air passes through the burner air box 2 and the air passage 5 to the air passage constriction 6. Under the action of the air passage constriction 6, the air velocity increases, generating an entraining effect that draws external flue gas into the gas mixing cylinder 15 for mixing, achieving a primary entrainment of the flue gas by the air. After being evenly mixed in the gas mixing cylinder 15, part of it is directly injected from the gas mixing cylinder 15 through the flare 14 into the furnace to assist combustion, and the other part enters... The flue gas mixes with the combustion gas in the duty sleeve 20 and is injected into the furnace through the swirl vanes 17 to aid combustion. The mixing of flue gas reduces the oxygen partial pressure in the combustion gas, thus reducing NOx formation. At the same time, the gas entering from the main gas pipeline 4 passes through the main flame gas pipe 19 and reaches the main flame ejector nozzle 9. It is then injected from the main flame ejector nozzle 9 into the main flame gas nozzle 12. Under the action of the main flame ejector nozzle 9, the flow velocity of the main combustion stage gas increases, generating an ejection effect. The gas then passes through several rear flue gas entrainment holes 10 and several front flue gas entrainment holes provided on the main flame gas nozzle 12. 11. External flue gas is drawn into the main flame gas nozzle 12 and mixed with the main combustion stage gas, achieving secondary entrainment of flue gas by the gas. After uniform mixing of gas and flue gas in the main flame gas nozzle 12, the mixture is injected into the furnace for combustion. A small amount of flue gas participates in secondary combustion, reducing the flame temperature. The resulting strong internal recirculation increases the mass flow rate of the medium-temperature endothermic working fluid in the flame zone, thereby reducing the amount of nitrogen oxides produced. The shift gas in the shift flame gas pipe 1 flows forward continuously. At the end of the shift flame gas pipe 1, a portion of the shift gas enters the shift flame short pipe 1. The gas is ejected from the 6th section. Under the partial obstruction of the end of the duty sleeve 20, this part mixes with the flue gas and air that are rotated by the swirl blade 17. Then, driven by this part of the duty gas, it flows towards the main flame gas nozzle 12 and merges with the mixture of main combustion stage gas and flue gas ejected from the main flame gas nozzle 12, which plays a role in stabilizing combustion. The remaining duty gas is directly ejected from the port of the duty flame gas pipe 1 and sprayed towards the front of the combustion device through several duty flame axial injection holes 18, providing axial momentum to the flame.

[0026] In summary, the flue gas recirculation ultra-low pollutant emission gas combustion device of the present invention divides the gas into a shift flame and a main combustion stage flame through the set shift flame gas pipe 1 and main flame gas delivery pipe 3, thereby completing fuel classification, avoiding flame concentration, and reducing local high temperature zones. The flue gas recirculation ultra-low pollutant emission gas combustion device of the present invention uses several shift flame short pipes 16 corresponding one-to-one with several main flame gas nozzles 12, with the shift flame short pipes 16 inclined towards the main flame gas nozzles 12, to stabilize combustion. The flue gas recirculation ultra-low pollutant emission gas combustion device of the present invention uses the high-speed fluid ejection effect formed by the air channel constriction 6 and the main flame ejector nozzle 9 to introduce flue gas into the combustion device through the main flue gas entrainment inlet 13, the rear flue gas entrainment hole 10, and the front flue gas entrainment hole 11, increasing the inert gas content in the combustion zone. Because the flue gas absorbs heat and dilutes the oxygen concentration, the combustion speed and temperature decrease, thereby inhibiting NOx formation.

[0027] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the invention. They can also be reasonable combinations of the features described in the above embodiments. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A flue gas internal circulation ultra-low pollutant emission gas combustion device, characterized in that: The system includes a standby flame gas pipe (1), a burner air box (2), a main gas passage (4), an air passage (5), a boiler refractory layer transition section (7), several main flame gas pipes (19), several main flame gas nozzles (12), and a gas mixing cylinder (15). The burner air box (2) and the air passage (5) are connected. The outer ring of the air passage (5) is concentrically provided with the main gas passage (4) and the boiler refractory layer transition section (7). The main gas passage (4) and the boiler refractory layer transition section (7) are connected. After the air passage (5) passes through the boiler refractory layer transition section (7), an air vent is provided at the end. The boiler refractory transition section (7) is equipped with several main flame gas pipes (19). One end of the main flame gas pipe (19) is connected to the main gas channel (4), and the other end passes through the boiler refractory transition section (7) and is equipped with a main flame ejector nozzle (9) at the end. The main flame ejector nozzle (9) is fitted with a main flame gas nozzle (12). Several flue gas entrainment holes are provided on the main flame gas nozzle (12). A gas mixing cylinder (15) is provided inside the several main flame gas nozzles (12). The gas mixing cylinder (15) is located in front of the air channel narrowing (6). The duty flame gas pipe (1) passes through the center of the burner wind box (2), air passage (5) and gas mixing cylinder (15), and has several duty flame short pipes (16) installed at the end at an angle; The end of the duty flame gas pipe (1) is also fitted with a duty sleeve (20), and the duty sleeve (20) is provided with a swirl vane (17); the duty flame short pipe (16) passes through the swirl vane (17); the end of the duty sleeve (20) is higher than the swirl vane (17) and partially blocks the gas outlet of the duty flame short pipe (16); The swirl blade (17) is provided with several axial injection holes (18) for the duty flame.

2. The flue gas internal circulation ultra-low pollutant emission gas combustion device according to claim 1, characterized in that: The aforementioned number of duty flame short pipes (16) correspond one-to-one with the number of main flame gas nozzles (12), and the duty flame short pipes (16) are inclined towards the main flame gas nozzles (12).

3. The flue gas internal circulation ultra-low pollutant emission gas combustion device according to claim 1 or 2, characterized in that: The plurality of flue gas entrainment holes include a plurality of rear flue gas entrainment holes (10) and a plurality of front flue gas entrainment holes (11). The plurality of rear flue gas entrainment holes (10) are disposed on the pipe wall of the main flame gas nozzle (12) on the outer periphery of the main flame ejector nozzle (9), and the plurality of front flue gas entrainment holes (11) are disposed on the pipe wall of the main flame gas nozzle (12) in front of the main flame ejector nozzle (9).

4. The flue gas internal circulation ultra-low pollutant emission gas combustion device according to claim 3, characterized in that: The width of the rear smoke suction hole (10) is greater than that of the front smoke suction hole (11), and the length of the rear smoke suction hole (10) is less than that of the front smoke suction hole (11).

5. The flue gas internal circulation ultra-low pollutant emission gas combustion device according to claim 1, 2 or 4, characterized in that: The gas mixing cylinder (15) is provided with a main flue gas inlet (13) at one end facing the air channel constriction (6), and a flared end (14) at the other end.

6. The flue gas internal circulation ultra-low pollutant emission gas combustion device according to claim 5, characterized in that: The end of the air passage constriction (6) extends into the main flue gas inlet (13).

7. The flue gas internal circulation ultra-low pollutant emission gas combustion device according to claim 1, characterized in that: The boiler refractory transition section (7) is provided with a main flame support plate (8) at its end. The main flame support plate (8) supports the air passage (5) and several main flame gas pipes (19).

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