A novel premixed internal circulation low-pollutant gas combustion device

Abstract

This invention discloses a novel premixed internal circulation low-pollutant gas combustion device, relating to the field of burner technology, and solves the problem of excessive initial emissions of nitrogen oxides in existing gas-fired boilers. The invention features a main flame ejector nozzle externally fitted with a main flame gas nozzle; the main flame gas nozzle has several flue gas entrainment holes; the air passage end has an air passage constriction; the end of the standby flame gas pipe extends into the gas mixing cylinder and has several standby flame short pipes at its end; a standby gas premixing pipe is installed inside the standby flame gas pipe, and the standby gas premixing pipe is connected to the burner airbox via the air premixing pipe. This invention performs partial air premixing inside the standby gas premixing pipe, increasing the combustion speed of the standby gas; by introducing flue gas into the combustion device, the inert gas content in the combustion zone increases, and because the flue gas absorbs heat and dilutes the oxygen concentration, the combustion speed and temperature decrease, thereby inhibiting NOx formation.

Description

Technical Field

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

[0002] Compared to coal, natural gas combustion produces lower emissions of sulfur dioxide and particulate matter, and its carbon dioxide emissions are significantly lower than those of coal and petroleum fuels. However, due to the high combustion temperature, nitrogen oxide emissions are a prominent issue during natural gas combustion. Nitrogen oxides are among the most significant atmospheric pollutants, contributing not only to photochemical smog but also being a major contributor to ozone layer depletion, posing serious threats to the ecological environment and human health. With increasingly stringent nitrogen oxide emission standards in my country, the mass concentration of nitrogen oxide emissions is generally limited to 50 mg / m³. 3 Around that time, many developed provinces and cities have proposed stricter NOx emission standards. However, the initial NOx emission levels of the vast majority of currently used gas-fired boilers are generally between 150 and 200 mg / m³. 3 The levels of nitrogen oxides (NOx) in the initial emissions are severely exceeding standards. With the implementation of new boiler emission standards, low-NOx control has received significant attention from governments at all levels and the public. Therefore, there is a need to develop a gas 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 a novel premixed internal circulation low-pollutant gas combustion device. 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 novel premixed internal circulation low-pollutant gas combustion device, specifically comprising a standby flame gas pipe, a burner air box, a main gas passage, an air passage, a main flame support frame, several main flame gas pipes, several main flame gas nozzles, a gas mixing cylinder, and a standby sleeve. The combustion air box and the air passage are connected. The main gas passage and the main flame support frame are concentrically arranged around the outer ring of the air passage, and the main gas passage and the main flame support frame are connected. After passing through the main flame support frame, the air passage has an air passage constriction at its end. Several main flame gas pipes are arranged inside the main flame support frame. One end of each main flame gas pipe is connected to the main gas passage, and the other end passes through the main flame support frame 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 provided on the main flame gas nozzle. The gas mixing cylinder is fitted outside the standby flame gas pipe and inside the several main flame gas nozzles, and is located in front of the air passage constriction.

[0005] The duty flame gas pipe passes through the center of the combustion air box and air passage and extends into the gas mixing cylinder; the duty sleeve is fitted on the duty flame gas pipe, and the front end of the duty sleeve extends out of the gas mixing cylinder; several duty flame short pipes are provided on the duty flame gas pipe, and several duty flame short pipes are set inside the duty sleeve.

[0006] The duty flame gas pipe is coaxially equipped with a duty flame premixing pipe; the duty flame premixing pipe is equipped with an air premixing pipe, which is connected to the burner air box.

[0007] Furthermore, an air guide plate is provided inside the burner air box.

[0008] Furthermore, a radial injection port for the duty flame is provided on the side wall of the end of the duty flame short tube.

[0009] 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.

[0010] 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.

[0011] 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 gas mixing cylinder flare at the other end.

[0012] Furthermore, the air passage narrows and extends into the main flue gas intake port.

[0013] Furthermore, the end of the duty flame gas pipe is provided with swirl vanes.

[0014] Furthermore, the swirl blades are provided with a plurality of axial injection holes for the standby flame, and the plurality of axial injection holes for the standby flame are connected to the standby flame premixing pipe.

[0015] Furthermore, the aforementioned short flame tubes pass through the swirl vanes.

[0016] The beneficial effects of the novel premixed internal circulation low-pollutant gas combustion device described in this invention are as follows:

[0017] (1) The novel premixed internal circulation low pollutant gas combustion device of the present invention divides the gas into a duty flame and a main combustion stage flame by setting a duty flame gas pipe and a main flame gas delivery pipe, thereby completing fuel classification, controlling the equivalence ratio of the combustion zone, i.e. the flame temperature, and thus suppressing the main thermal NO in NOx during the combustion process.

[0018] (2) The novel premixed internal circulation low pollutant gas combustion device of the present invention completes the premixing between part of the gas and air through the air premixing pipe and the duty gas premixing pipe, thereby improving the gas combustion speed and playing a role in stabilizing combustion.

[0019] (3) The novel premixed internal circulation low pollutant gas combustion device of the present invention introduces flue gas into the combustion device through the high-speed fluid formed by the narrowing of the air channel 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 content of inert gas 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

[0020] 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.

[0021] In the attached diagram:

[0022] Figure 1 This is a schematic diagram of the structure of a novel premixed internal circulation low-pollutant gas combustion device according to the present invention;

[0023] Figure 2 This is a side view of a novel premixed internal circulation low-pollutant gas combustion device according to the present invention;

[0024] Figure 3 This is a schematic diagram of the main flame gas nozzle of a novel premixed internal circulation low-pollutant gas combustion device according to the present invention;

[0025] Among them: 1-Stationary flame gas pipe, 2-Burner air box, 3-Air premixing pipe, 4-Stationary gas premixing pipe, 5-Air guide plate, 6-Main flame gas delivery pipe, 7-Main gas passage, 8-Air passage, 9-Air passage constriction, 10-Main flame support frame, 11-Main flame support plate, 12-Main flame flue gas ejector nozzle, 13-Rear flue gas entrainment hole, 14-Front flue gas entrainment hole, 15-Main flame gas nozzle, 16-Main flue gas entrainment inlet, 17-Gas mixing cylinder flare, 18-Gas mixing cylinder, 19-Stationary sleeve, 20-Stationary flame short pipe, 21-Swirl vane, 22-Stationary flame radial injection hole, 23-Stationary flare, 24-Stationary flame axial injection hole, 25-Main flame gas pipe. Detailed Implementation

[0026] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings:

[0027] Specific implementation method one: See Figures 1-3 This embodiment is described in detail. The novel premixed internal circulation low-pollutant gas combustion device described in this embodiment specifically includes a standby flame gas pipe 1, a burner air box 2, a main gas passage 7, an air passage 8, a main flame support frame 10, several main flame gas pipes 25, several main flame gas nozzles 15, a gas mixing cylinder 18, and a standby sleeve 19. The combustion air box 2 and the air passage 8 are connected to provide oxygen for the combustion process. The main gas passage 7 and the main flame support frame 10 are concentrically arranged on the outer ring of the air passage 8. One end of the main gas passage 7 is connected to the burner air box 2, and the other end is connected to the main flame support frame 10. A main flame support plate 11 is provided at the end of the main flame support frame 10, which supports the air passage 8 and several main flame gas pipes 25. After passing through the main flame support frame 10, the air passage 8 has an air passage constriction 9 at its end, allowing air to flow out of the air passage 8 and then... The velocity is increased, forming a high-speed fluid that generates an ejector effect, entraining the smoke gas; the main flame support frame 10 is provided with several main flame gas pipes 25, one end of which is connected to the main gas channel 7, and the other end passes through the main flame support frame 10 and is provided with a main flame ejector nozzle 12 at the end; the several main flame gas pipes 25 are evenly distributed on the outer ring of the main gas channel 7; the main flame ejector nozzle 12 is fitted with a main flame gas nozzle 15; the main flame gas nozzle 15 is provided with several smoke gas entrainment holes, and the gas is injected into the main flame gas nozzle 15 through the main flame ejector nozzle 12 to increase the gas flow velocity, forming a high-speed fluid that generates an ejector effect, drawing the smoke gas from the front and rear smoke gas entrainment holes into the main flame gas nozzle 15; the gas mixing cylinder 18 is fitted outside the duty flame gas pipe 1 and inside the several main flame gas nozzles 15, and is located in front of the air channel constriction 9;

[0028] The duty flame gas pipe 1 passes through the center of the combustion air box 2 and the air channel 8 and extends into the gas mixing cylinder 18; the duty sleeve 19 is fitted onto the duty flame gas pipe 1, the main body of the duty sleeve 19 is inside the gas mixing cylinder 18, and the duty flare 23 at the front end of the duty sleeve 19 extends out from the front end of the gas mixing cylinder 18; a number of duty flame short pipes 20 are provided on the duty flame gas pipe 1, and the number of duty flame short pipes 20 are provided inside the duty sleeve 19; the duty flame short pipe 20 is an L-shaped pipe, the short side of the L-shape of the duty flame short pipe 20 is vertically connected to the duty flame gas pipe 1, and the long side of the L-shape of the duty flame short pipe 20 is parallel to the duty flame gas pipe 1.

[0029] The duty flame gas pipe 1 is coaxially equipped with a duty flame premixing pipe 4; an air premixing pipe 3 is installed on the duty flame premixing pipe 4, which is connected to the burner air box 2; the air inlet end of the duty flame premixing pipe 4 is equipped with a constriction structure. After a part of the duty flame gas enters the duty flame premixing pipe 4 through the constriction structure, the gas flow rate increases and generates an ejector effect, thereby drawing air from the burner air box 2 into the duty flame premixing pipe 4 through the air premixing pipe 3, and mixing it with the gas.

[0030] The burner air box 2 is equipped with an air guide plate 5. Air enters the air channel 8 smoothly through the air guide plate 5, making the air flow field distribution more uniform.

[0031] The duty flame short pipe 20 is provided with a duty flame radial injection port 22 on the end side wall. The duty flame gas is injected from the duty flame radial injection port 22 into the duty sleeve 19 in the radial direction of the duty flame short pipe 20 to enhance the mixing effect of gas, flue gas and air.

[0032] The plurality of flue gas entrainment holes include a plurality of rear flue gas entrainment holes 13 and a plurality of front flue gas entrainment holes 14. The plurality of rear flue gas entrainment holes 13 are disposed on the pipe wall of the main flame gas injection pipe 15 on the outer periphery of the main flame ejector nozzle 12, and the plurality of front flue gas entrainment holes 14 are disposed on the pipe wall of the main flame gas injection pipe 15 in front of the main flame ejector nozzle 12. When the main combustion stage gas is ejected from the main flame ejector nozzle 12, 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 13 and the plurality of front flue gas entrainment holes 14 into the main flame gas injection pipe 15. The width of the rear flue gas entrainment hole 13 is greater than that of the front flue gas entrainment hole 14, and the length of the rear flue gas entrainment hole 13 is less than that of the front flue gas entrainment hole 14.

[0033] The gas mixing cylinder 18 is provided with a main flue gas inlet 16 at one end facing the air channel constriction 9, and a gas mixing cylinder expansion 17 at the other end; the air channel constriction 9 extends into the main flue gas inlet 16, thereby ensuring that the air can be fully entered into the gas mixing cylinder 18 after being accelerated by the air channel constriction 9.

[0034] The end of the duty flame gas pipe 1 is provided with a swirl vane 21. The edge of the swirl vane 21 leaves a certain gap with the inner wall of the duty sleeve 19. Several duty flame axial injection ports 24 are provided on the swirl vane 21. Several duty flame axial injection ports 24 are connected to the duty flame premixing pipe 4. After the flue gas and air pass through the swirl vane 21, they rotate in the duty sleeve 19 and fully mix with a part of the duty flame gas flow ejected from the duty flame radial injection port 22. Under the action of this part of the gas flow, it rotates forward along the inner wall of the duty sleeve 19. Another part of the duty flame gas flow is ejected from the end of the duty flame premixing pipe 4 through several duty flame axial injection ports 24 provided on the swirl vane 18, which drives the mixed gas to move forward and extend into the furnace for combustion. At the same time, the duty expansion port 23 is used to delay its mixing with the external combustion-supporting gas, reduce the formation of the high-temperature zone at the injection port, and generate flame superposition with the gas ejected from the main flame gas pipe 15 at a certain position, which plays a role in stabilizing combustion.

[0035] Several short flame tubes 20 connected to the flame combustion pipe 1 are located on one side of the swirl vane 21, while the ends of the short flame tubes 20 with the flame radial injection ports 22 pass through the swirl vane 21, placing them on the other side. The mixture of flue gas and air, after passing through the swirl vane 21, adheres to the inner wall of the flame sleeve 19 and rotates forward. The flame combustion gas ejected from the flame radial injection ports 22 does not pass through the swirl vane 21 and therefore does not rotate. This portion of the flame combustion gas comes into full contact with the flue gas and air, further enhancing the mixing effect between the three gases.

[0036] The main gas passage 7 is equipped with a main flame gas delivery pipe 6, which provides main combustion stage gas to the combustion device.

[0037] The specific working process of the novel premixed internal circulation low-pollutant gas combustion device described in this invention is as follows:

[0038] Gas is introduced into the duty flame gas pipe 1 and the main gas passage 7, and air is introduced into the combustion device from the burner wind box 2. Most of the air passes through the burner wind box 2 and the air passage 8 to the air passage constriction 9. Under the action of the air passage constriction 9, the air velocity increases, generating an entraining effect that draws external flue gas through the main flue gas entrainment inlet 16 into the gas mixing cylinder 18 for mixing, achieving one entrainment of the flue gas by the air. In the gas mixing cylinder 18, part of the mixed gas is rotated and mixed evenly by the action of the swirl blades 21 and is directly sprayed out from the gas mixing cylinder expansion 17 at the front end of the gas mixing cylinder 18. The other part enters the duty sleeve 19 and mixes with the duty fuel gas. Finally, it is injected into the furnace through the duty expansion 23 to assist combustion. The mixing of flue gas reduces the oxygen partial pressure in the combustion gas and lowers NO. x is generated; at the same time, the gas entering from the main gas passage 7 passes through the main flame gas pipe 25 and reaches the main flame ejector nozzle 12. It is injected from the main flame ejector nozzle 12 into the main flame gas nozzle 15. Under the action of the main flame ejector nozzle 12, the flow rate of the main combustion stage gas increases, generating an ejection effect. Through several rear flue gas entrainment holes 13 and several front flue gas entrainment holes 14 provided on the main flame gas nozzle 15, the external flue gas is sucked into the main flame gas nozzle 15 and mixed with the main combustion stage gas, realizing the secondary entrainment of flue gas by the gas. After the gas and flue gas are uniformly mixed in the main flame gas nozzle 18, they are injected into the furnace for combustion. A small amount of flue gas participates in the second combustion, reducing the flame temperature. The strong internal backflow formed increases the mass flow rate of the medium-temperature heat-absorbing working fluid in the flame zone to achieve the goal of reducing the amount of nitrogen oxides generated.

[0039] The duty gas in the duty flame gas pipe 1 is divided into two parts. One part flows forward and enters the duty flame short pipe 20 at the end of the duty flame gas pipe 1 and is ejected through the duty flame radial injection port 22, where it mixes with the flue gas that has been rotated by the action of the swirl vane 21 and the air. The other part of the duty gas enters the duty gas premixing pipe 4 from the duty flame gas pipe 1 and is premixed with the air that enters through the air premixing pipe 3. The premixed gas moves forward to the end of the duty gas premixing pipe 4 and is ejected from the duty flame axial injection port 24. The mixed gas in the duty sleeve 19 rotates along the inner wall of the duty sleeve 19 and extends axially into the furnace for combustion. Under the action of the duty flame expansion port 23, its contact with the combustion-supporting gas in the gas mixing cylinder 18 is delayed, reducing the ignition heat and making the combustion more stable.

[0040] In summary, the novel premixed internal circulation low-pollutant gas combustion device of this invention divides the gas into a shift flame and a main combustion stage flame through a shift flame gas pipe 1 and a main flame gas delivery pipe 6, thus completing fuel grading and controlling the equivalence ratio of the combustion zone, i.e., the flame temperature, thereby suppressing the main thermal NO in NOx during combustion. Furthermore, the device uses an air premixing pipe 3 and a shift gas premixing pipe 4 to premix some of the gas with air, increasing the combustion speed and stabilizing combustion. Finally, the device utilizes the high-speed fluid ejection effect formed by the air channel constriction 9 and the main flame ejector nozzle 12 to introduce flue gas into the combustion device through the main flue gas inlet 16, the rear flue gas inlet 13, and the front flue gas inlet 14, 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 suppressing NOx formation.

[0041] 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 novel premixed internally recirculating low pollutant gas combustion device characterized by: The system includes a standby flame gas pipe (1), a burner air box (2), a main gas passage (7), an air passage (8), a main flame support frame (10), several main flame gas pipes (25), several main flame gas nozzles (15), a gas mixing cylinder (18), and a standby sleeve (19). The burner air box (2) and the air passage (8) are connected. The main gas passage (7) and the main flame support frame (10) are concentrically arranged on the outer ring of the air passage (8). The main gas passage (7) and the main flame support frame (10) are connected. After the air passage (8) passes through the main flame support frame (10), an air vent is provided at the end. The main flame support frame (10) is equipped with several main flame gas pipes (25). One end of the main flame gas pipe (25) is connected to the main gas channel (7), and the other end passes through the main flame support frame (10) and is equipped with a main flame ejector nozzle (12) at the end. The main flame ejector nozzle (12) is fitted with a main flame gas nozzle (15). Several flue gas suction holes are provided on the main flame gas nozzle (15). The gas mixing cylinder (18) is fitted outside the duty flame gas pipe (1) and inside the several main flame gas nozzles (15), and is located in front of the air channel narrowing (9). The duty flame gas pipe (1) passes through the center of the burner air box (2) and the air passage (8) and extends into the gas mixing cylinder (18); the duty sleeve (19) is fitted on the duty flame gas pipe (1), and the front end of the duty sleeve (19) extends out of the gas mixing cylinder (18); a number of duty flame short pipes (20) are provided on the duty flame gas pipe (1), and the number of duty flame short pipes (20) are provided inside the duty sleeve (19); The duty flame gas pipe (1) is coaxially equipped with a duty flame premixing pipe (4); an air premixing pipe (3) is installed on the duty flame premixing pipe (4) and is connected to the burner air box (2) through the air premixing pipe (3); The plurality of flue gas entrainment holes include a plurality of rear flue gas entrainment holes (13) and a plurality of front flue gas entrainment holes (14). The plurality of rear flue gas entrainment holes (13) are disposed on the pipe wall of the main flame gas injection pipe (15) on the outer periphery of the main flame ejector nozzle (12), and the plurality of front flue gas entrainment holes (14) are disposed on the pipe wall of the main flame gas injection pipe (15) in front of the main flame ejector nozzle (12). The width of the rear flue gas entrainment holes (13) is greater than that of the front flue gas entrainment holes (14), and the length of the rear flue gas entrainment holes (13) is less than that of the front flue gas entrainment holes (14). The end of the duty flame gas pipe (1) is provided with a swirl vane (21); a gap is provided between the edge of the swirl vane (21) and the inner wall of the duty sleeve (19); several duty flame short pipes (20) pass through the swirl vane (21); A radial jet nozzle (22) for the duty flame is provided on the side wall of the end of the duty flame short tube (20).

2. The novel premixing internal low pollutant gas combustion device according to claim 1, characterized in that: An air guide plate (5) is provided inside the burner air box (2).

3. The novel premixing internal low pollutant gas combustion device according to claim 1 or 2, characterized in that: The gas mixing cylinder (18) is provided with a main flue gas inlet (16) at one end facing the air channel constriction (9), and a gas mixing cylinder flare (17) at the other end.

4. The novel premixed internal circulation low-pollutant gas combustion device according to claim 3, characterized in that: The air passage constriction (9) extends into the main flue gas inlet (16).

5. The novel premixed internal circulation low-pollutant gas combustion device according to claim 1, characterized in that: The swirl blade (21) is provided with a number of duty flame axial injection holes (24), and the number of duty flame axial injection holes (24) are connected to the duty flame premixing pipe (4).

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