Fuel gas low-nitrogen air duct burner

Abstract

A fuel gas low-nitrogen air duct combustor comprises an ignition gun assembly, a fuel gas chamber, a combustor cylinder, a center spray gun, an inner-layer spray gun, a stable combustion device, an outer-layer spray gun and a conical-head tower-shaped fire cylinder. The combustor cylinder is connected with the fuel gas chamber, the center spray gun is arranged in the middle of the fuel gas chamber, the stable combustion device is arranged at the head of the center spray gun, an inner-layer spray gun and an outer-layer spray gun are arranged in the combustor cylinder, the conical-head tower-shaped fire cylinder is of an expanded cone structure, and cooling and combustion-supporting air holes playing roles in stabilizing combustion and guaranteeing the shape of flames are formed in the outer wall of the conical-head tower-shaped fire cylinder. The device is suitable for various working conditions of primary air duct heating. The spray guns on the inner layer and the outer layer are arranged in a layered mode, staged combustion is achieved, oxygen-enriched combustion is adopted in the first stage, NOx is generated through combustion, N2 is generated through NOx in the reducing atmosphere in the second stage combustion, and therefore generation of NOx is reduced. The two sets of gas pipelines are independently adjusted, the mixing process of gas and combustion-supporting air is reasonably organized, a local high-temperature area is avoided, the average temperature of flames in the furnace is reduced, and then generation of NOx is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of combustor, concretely relates to a low nitrogen air duct combustor for gas suitable for power station boiler air duct combustion and reducing NOx emission. TECHNICAL BACKGROUND

[0002] Air duct combustor is to utilize gas or fuel to burn in air duct and produce high temperature, and directly heats primary air flowing through air duct, and air duct combustor has wide application in multiple fields by virtue of its unique combustion mode and performance characteristics, and with the improvement of environmental protection standard, it is important measure to reduce NOx emission for power station boiler air duct combustor to adopt low nitrogen combustion technology, and it is helpful to sustainable development of electric power industry and environmental protection. The nitrogen oxides generated by gas combustor are mainly thermal NOx. Therefore, considering the generation mechanism of NOx, for gas combustor, the mixing process of gas and combustion air should be reasonably organized, local high temperature area in furnace should be avoided, average temperature in furnace should be reduced, and convection heat transfer and radiation heat transfer of flame should be enhanced. Low nitrogen air duct combustor is a kind of combustion equipment aiming at reducing nitrogen oxides (NOx) emission, and is widely applied to various industrial processes needing combustion heating. Combustion process is divided into multiple stages. In initial stage, part of fuel is incompletely combusted with small amount of air, temperature in this area is relatively low, and generated NOx is less. Subsequently, remaining air mixes with incomplete combustion product downstream and continues to combust. Since overall combustion process is lengthened, local high temperature area is reduced, and generation of thermal NOx is inhibited, SUMMARY

[0003] Technical problem: the utility model aims at overcoming the deficiency in prior art, and provides a low nitrogen air duct combustor for gas, which has simple structure, is easy to ignite, flame is stable, and can reduce NOx emission.

[0004] Technical solution: The utility model discloses a kind of low-nitrogen air duct combustor of gas, including inner layer spray gun air inlet, ignition gun assembly, gas chamber, outer layer spray gun air inlet, combustor cylinder, center spray gun;The combustor cylinder includes air inlet cylinder and combustor nozzle pipe connected with external air pipe flange, the front end of the combustor nozzle pipe is connected with gas chamber flange, the outlet of combustor nozzle pipe is equipped with a cone head tower-shaped fire tube, the cone head of the cone head tower-shaped fire tube inlet is equipped with combustion stabilizer, the gas chamber includes two parts of inner layer gas chamber and outer layer gas chamber, inner layer spray gun air inlet that gas chamber end surface is equipped with and enters inner layer gas chamber gas, outer layer spray gun air inlet that gas chamber lower side is equipped with and enters outer layer gas chamber gas, the middle part of gas chamber is equipped with center spray gun that passes through inner layer gas chamber and combustor nozzle pipe and enters into combustion stabilizer, the upper side of the center spray gun is equipped with ignition gun assembly that passes through inner layer gas chamber and combustor nozzle pipe and enters into cone head tower-shaped fire tube, the circular partition disc is respectively equipped with inner layer spray gun and outer layer spray gun that enters combustor nozzle pipe to pipe opening distance M and is communicated with outer layer gas chamber in cone head tower-shaped fire tube in the communication with inner layer gas chamber in the circular partition disc, the inner layer spray gun is evenly distributed around the cone head of cone head tower-shaped fire tube, and the outer layer spray gun is evenly distributed around the periphery of cone head tower-shaped fire tube;The cone head tower-shaped fire tube and combustion stabilizer are concentrically welded and fixed, and the cone head tower-shaped fire tube is in the form of expanding cone, and combustion-supporting and cooling air hole that plays the role of stabilizing combustion and ensuring flame shape is arranged on the outer wall of the cone cylinder of the cone head tower-shaped fire tube.

[0005] The ignition gun assembly includes ignition gun conduit and ignition gun arranged in ignition gun conduit and can be advanced and retreated, and the ignition gun conduit passes through gas chamber and is welded and fixed with the gas chamber, and the front end of the ignition gun conduit is fixed at the cone face inlet of the cone head tower-shaped fire tube and is parallel to the airflow flowing direction in the combustor cylinder.

[0006] The gas chamber and the combustor cylinder are coaxially fixed, and the area ratio of the inner layer gas chamber and the outer layer gas chamber of the gas chamber is determined according to the gas flow and the gas pressure condition.

[0007] The center spray gun includes center spray gun connector, center spray gun barrel and center spray gun nozzle, the center spray gun barrel is welded and fixed with the gas chamber, the center spray gun connector is threadedly connected with the external gas pipeline through a metal hose, the center spray gun nozzle is concentrically welded and connected with the combustion stabilizer, the center spray gun nozzle is provided with 1-3 circles of oblique nozzles, the number of oblique nozzles in each circle is 4-16, the oblique nozzles are evenly distributed around the center circle of the center spray gun, the diameter of the oblique nozzles is 2-10 mm, the center line of the oblique nozzles of the center spray gun nozzle forms an angle A with the center line of the center spray gun, and the angle A is 20-70°.

[0008] The inner layer lance comprises an inner layer lance barrel and an inner layer lance nozzle arranged on the inner layer lance barrel, the lance barrel is welded on a circular partition disc at an inner layer gas chamber, is uniformly distributed on the outside of the central lance, and the inner layer lance nozzle is arranged at an inclination angle B to the center of the burner.

[0009] The stable combustion device comprises an axial swirling vane and an outer ring, the axial swirling vane is fixed on the outer ring in a fan-shaped arrangement to form a swirling air flow.

[0010] The outer layer lance comprises an outer layer lance barrel and an outer layer lance nozzle arranged on the outer layer lance barrel, the outer layer lance barrel is welded on a circular partition disc at an outer layer gas chamber, is uniformly distributed on the outside of the inner layer lance, and the outer layer lance nozzle comprises 1-3 circles of spray holes, the number of spray holes in each circle is 1-12, the spray holes are uniformly distributed in a circle, the diameter of the spray holes is 2-10 mm, the number of spray holes is determined according to the gas flow and gas pressure, the radial distance between the outer layer lance nozzle and the outer edge of the conical tower-shaped combustion chamber is 10-30 mm, and the distance M between the outer layer lance nozzle and the end surface of the conical tower-shaped combustion chamber is 20-50 mm.

[0011] The conical tower-shaped combustion chamber comprises a conical pipe transition pipe, a stable combustion expansion cone transition pipe and a cooling expansion cone transition pipe which are sequentially welded together, one end of the conical pipe transition pipe is concentrically welded to the outer ring of the stable combustion device, and the taper C of the conical pipe transition pipe is 90-150°; the stable combustion expansion cone transition pipe is provided with at least two circles of combustion-supporting holes on the conical surface, the number of holes in each circle is 8-30, the diameter of the holes is 10-50 mm, and the combustion-supporting holes in each circle are arranged at intervals; the cooling expansion cone transition pipe is provided with at least one circle of cooling holes (b) on the circumference, the cooling holes are arranged at intervals, the number of the cooling holes is 8-30, and the diameter of the cooling holes is 10-50 mm.

[0012] The biggest advantage of the utility model lies in that it can effectively reduce NOx emission and meet the increasingly strict environmental protection regulation requirements. Meanwhile, the advanced structure design and combustion control technology ensure the stability of the combustion process. Even in the case of large load change, the low nitrogen air duct burner can maintain good combustion state, avoid flame extinguishing or unstable combustion phenomenon and ensure the continuous and reliable operation of the equipment. The burner cone head tower-shaped fire barrel has an expanding cone structure, cooling and combustion air holes are arranged on the outer wall of the cone cylinder, the flame shape and length can be ensured, the flame is stable and rigid, the low nitrogen air duct burner can be applied to various primary air duct heating working conditions, even in the case of large load change, the low nitrogen air duct burner can maintain good combustion state, avoid flame extinguishing or unstable combustion phenomenon and ensure the continuous and reliable operation of the equipment. The inner and outer layer spray guns are arranged in layers, which belongs to fuel staged combustion, the first stage is oxygen-enriched combustion, the NOx generated in the first stage combustion is reduced to N2 in the second stage combustion by introducing secondary fuel, thereby reducing the generation of NOx. Meanwhile, the two sets of gas pipelines are separately adjusted, the mixing process of the gas and the combustion air is reasonably organized, local high temperature zones are avoided, the average temperature of the flame in the furnace is reduced, and the generation of NOx is reduced. The biggest advantage of the low nitrogen air duct burner lies in that it can effectively reduce NOx emission and meet the increasingly strict environmental protection regulation requirements. Compared with the traditional burner, the low nitrogen air duct burner can reduce the NOx emission by 30%-70%, greatly reduces the pollution to the atmospheric environment and helps to improve the air quality, and has wide practicability in the technical field. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is a structure schematic view of the utility model.

[0014] Figure 2 It is a structure schematic view of the cone head tower-shaped fire barrel of the utility model.

[0015] In the drawing: 1-inner layer spray gun air inlet, 2-ignition gun assembly, 2.1-ignition gun, 2.2-ignition gun conduit, 3-gas chamber, 3.1-inner layer gas chamber, 3.2-outer layer gas chamber, 3.3-circular partition disc, 4-outer layer spray gun air inlet, 5-burner cylinder, 5.1-air inlet cylinder, 5.2-burner nozzle pipe, 6-center spray gun, 6.1-center spray gun joint, 6.2-center spray gun barrel, 6.3-center spray gun nozzle, 7-inner layer spray gun, 7.1-inner layer spray gun barrel, 7.2-inner layer spray gun nozzle, 8-combustion stabilizing device, 8.1-cyclone blade, 8.2-outer ring, 9-outer layer spray gun, 9.1-outer layer spray gun barrel, 9.2-outer layer spray gun nozzle, 10-cone head tower-shaped fire barrel, 10.1-cone pipe transition pipe, 10.2-fire stabilizing expanding cone transition pipe, 10.3-cooling expanding cone transition pipe. DETAILED DESCRIPTION

[0016] The utility model discloses further illustrate below combined with the embodiment in the drawing:

[0017] Figure 1 As shown in the utility model discloses a gas low nitrogen air duct combustor, mainly by inner layer spray gun air inlet 1, ignition gun subassembly 2, gas chamber 3, outer layer spray gun air inlet 4, combustor cylinder 5, center spray gun 6, inner layer spray gun 7, stable combustion device 8, outer layer spray gun 9 and cone tower shape fire tube 10 constitute, the combustor cylinder 5 include with the flange of external air pipe channel link's air inlet cylinder 5.1 and combustor nozzle pipe 5.2, combustor nozzle pipe 5.2 with gas chamber 3 flange connection, the combustor nozzle pipe 5.2 export inside is equipped with a cone tower shape fire tube 10, the cone tower shape fire tube 10 entrance cone head place is equipped with stable combustion device 8, the gas chamber 3 of the gas chamber 3.1 and outer layer gas chamber 3.2 two parts including, gas chamber 3 end surface is equipped with the inner layer spray gun air inlet 1 of the gas of inlaying gas chamber 3.1, gas chamber 3 below is equipped with the outer layer spray gun air inlet 4 of the gas of inlaying outer layer gas chamber 3.2, the middle part of gas chamber 3 is equipped with the center spray gun 6 of inlaying stable combustion device 8 through gas chamber 3.1 and combustor nozzle pipe 5.2, the upper of center spray gun 6 is equipped with the ignition gun subassembly 2 of inlaying cone tower shape fire tube 10 through gas chamber 3.1 and combustor nozzle pipe 5.2, the circular baffle 3.3 on be equipped with respectively with the inner layer spray gun 7 of inlaying cone tower shape fire tube 10 with gas chamber 3.1 and the outer layer spray gun 9 of inlaying combustor nozzle pipe 5.2 to the pipe mouth distance M place with outer layer gas chamber 3.2, the inner layer spray gun 7 surrounds the cone head upper circumference of cone tower shape fire tube 10 and is evenly distributed, the outer layer spray gun 9 surrounds the periphery of cone tower shape fire tube 10 and is evenly distributed, the cone tower shape fire tube 10 with stable combustion device 8 concentric welding fixed, and the cone tower shape fire tube 10 is the expansion cone structure, and the cone cylinder outer wall of cone tower shape fire tube 10 is equipped with the combustion-supporting and cooling air hole that plays the role of stable combustion and guarantees flame shape.

[0018] The ignition gun assembly 2 comprises an ignition gun conduit 2.2 and an ignition gun 2.1 arranged in the ignition gun conduit 2.2 and capable of advancing and retreating, the ignition gun conduit 2.2 penetrates the gas chamber 3 and is welded and fixed with the gas chamber 3, the front end of the ignition gun conduit 2.2 is fixed at the entrance of the tapered surface of the cone tower-shaped fire barrel 10 and is parallel to the gas flow direction in the burner barrel 5. The gas chamber 3 is coaxially fixed with the burner barrel 5, and the area ratio of the inner layer gas chamber 3.1 and the outer layer gas chamber 3.2 of the gas chamber 3 is determined according to the gas flow and gas pressure working condition. The center spray gun 6 comprises a center spray gun joint 6.1, a center spray gun barrel 6.2 and a center spray gun nozzle 6.3, the center spray gun barrel 6.2 is welded and fixed with the gas chamber 3, the center spray gun joint 6.1 is threadedly connected with the external gas pipeline through a metal hose, and the center spray gun nozzle 6.3 is coaxially welded and connected with the stable combustion device 8, the center spray gun nozzle 6.3 is provided with 1-3 rows of oblique spray holes, the number of the oblique spray holes in each row is 4-16, the oblique spray holes are uniformly distributed around the center circle of the center spray gun 6, the diameter of the oblique spray holes is 2-10 mm, the center line of the oblique spray holes of the center spray gun nozzle 6.3 forms an angle A with the center line of the center spray gun 6, and the angle A is 20-70°. The inner layer spray gun 7 comprises an inner layer spray gun barrel 7.1 and an inner layer spray gun nozzle 7.2 arranged on the inner layer spray gun barrel 7.1, the spray gun barrel 7.1 is welded on the circular baffle 3.3 located at the inner layer gas chamber 3.1 and is uniformly distributed around the outside of the center spray gun 6, and the inner layer spray gun nozzle 7.2 is arranged at an inclination angle B to the center of the burner; the spray holes on the nozzle 7.2 are 1-3 rows, the number of the spray holes in each row is 1-12, the diameter of the spray holes is 2-10 mm, the angle B between the nozzle 7.2 and the center line of the inner layer spray gun 7 is 20-70°, and the number of the spray holes is determined according to the gas flow and gas pressure working condition. The stable combustion device 8 comprises an axial rotational flow vane 8.1 and an outer ring 8.2, the axial rotational flow vane 8.1 is arranged in a fan shape and is welded and fixed on the outer ring 8.2. The outer layer spray gun 9 comprises an outer layer spray gun barrel 9.1 and an outer layer spray gun nozzle 9.2 arranged on the outer layer spray gun barrel 9.1, the outer layer spray gun barrel 9.1 is welded on the circular baffle 3.3 located at the outer layer gas chamber 3.2 and is uniformly distributed around the outside of the inner layer spray gun 7, and the outer layer spray gun nozzle 9.2 is 1-3 rows of spray holes, the number of the spray holes in each row is 1-12, the spray holes are uniformly distributed around the circle, the diameter of the spray holes is 2-10 mm, the number of the spray holes is determined according to the gas flow and gas pressure, the radial distance between the outer layer spray gun nozzle 9.2 and the outer edge of the cone tower-shaped fire barrel 10 is 10-30 mm, and the distance M between the outer layer spray gun nozzle 9.2 and the end surface of the cone tower-shaped fire barrel 10 is 20-50 mm.

[0019] Figure 2As shown, the conical head tower-shaped fire barrel 10 comprises a conical pipe transition pipe 10.1, a stable combustion expansion cone transition pipe 10.2 and a cooling expansion cone transition pipe 10.3 welded together in turn, one end of the conical pipe transition pipe 10.1 is welded and connected with the outer ring 8.2 on the stable combustion device 8 in a concentric manner, the taper C of the conical pipe transition pipe 10.1 is 90-150°; the conical surface of the stable combustion expansion cone transition pipe 10.2 is provided with at least two rows of combustion-supporting holes a, the number of holes in each row is 8-30, the hole diameter is 10-50mm, and the combustion-supporting holes in each row are arranged at intervals; the circumference of the cooling expansion cone transition pipe 10.3 is provided with at least one row of cooling holes b, the cooling holes are arranged at intervals, the number is 8-30, and the hole diameter is 10-50mm.

[0020] The present combustor adopts layered arrangement of inner and outer layer spray guns, designs two-stage fuel supply system, adjusts fuel ratio through different pipelines and nozzles of inner and outer layers, and is designed according to 20%-40% of inner layer fuel ratio. The ignition gun directly ignites the inner layer spray gun, the inner layer spray gun belongs to oxygen-enriched combustion, the fuel is fully burned in this stage, but a certain amount of NOx is generated. The outer layer spray gun belongs to secondary combustion, and the oxygen is relatively insufficient at this time, forming a reducing atmosphere. The NOx generated by the inner layer spray gun is introduced into the secondary combustion, and in this reducing environment, the first-stage generated NOx reacts with some components in the secondary fuel, such as unburned hydrocarbons, is reduced to N2, thereby directly reducing the emission amount of NOx, and further reducing the generation of NOx. Through the special structure design of the conical head tower-shaped fire barrel and the reasonable organization of the mixing process of fuel gas and combustion-supporting air, local high-temperature zones are avoided, the average temperature of the flame in the furnace is reduced, and the generation of NOx is reduced.

Claims

1. A gas low NOx flue gas burner characterized by: It includes inner layer lance inlet (1), ignition lance assembly (2), gas chamber (3), outer layer lance inlet (4), burner cylinder (5), center lance (6); the burner cylinder (5) includes the air inlet cylinder (5.1) connected with the external air pipe flange and the burner nozzle pipe (5.2) connected with the gas chamber (3) flange, the outlet of the burner nozzle pipe (5.2) is internally provided with a tapered tower-shaped fire tube (10), the tapered tower-shaped fire tube (10) is provided with a stable combustion device (8) at the tapered head of the inlet, the gas chamber (3) includes inner layer gas chamber (3.1) and outer layer gas chamber (3.2) and circular partition disc (3.3), the gas chamber (3) is provided with inner layer lance inlet (1) on the end surface, the gas chamber (3) is provided with outer layer lance inlet (4) below, the gas chamber (3) is provided with center lance (6) in the middle part, the center lance (6) is provided with ignition lance assembly (2) above, the circular partition disc (3.3) is provided with inner layer lance (7) and outer layer lance (9) respectively, the inner layer lance (7) is distributed around the tapered head of the tapered tower-shaped fire tube (10), the outer layer lance (9) is distributed around the outer periphery of the tapered tower-shaped fire tube (10); the tapered tower-shaped fire tube (10) is concentrically welded and fixed with the stable combustion device (8), the tapered tower-shaped fire tube (10) is of expansion cone structure, the tapered tower-shaped fire tube (10) is provided with combustion-supporting and cooling air holes for stable combustion and ensuring the shape of the flame.

2. A gas low NOx duct burner according to claim 1, characterized in that: The ignition lance assembly (2) includes ignition lance guide pipe (2.2) and ignition lance (2.1) arranged in the ignition lance guide pipe (2.2) and capable of advancing and retreating, the ignition lance guide pipe (2.2) passes through the gas chamber (3) and is welded and fixed with the gas chamber (3), the front end of the ignition lance guide pipe (2.2) is fixed at the tapered face inlet of the tapered tower-shaped fire tube (10) and is parallel to the gas flow direction in the burner cylinder (5).

3. A gas low NOx duct burner according to claim 1, characterized in that: The gas chamber (3) is coaxially fixed with the burner cylinder (5), the area ratio of the inner layer gas chamber (3.1) and the outer layer gas chamber (3.2) of the gas chamber (3) is determined according to the gas flow and gas pressure working condition.

4. A gas low NOx duct burner according to claim 1, characterized in that: The center lance (6) comprises a center lance joint (6.1), a center lance barrel (6.2) and a center lance nozzle (6.3), the center lance barrel (6.2) is welded and fixed with the gas chamber (3), the center lance joint (6.1) is threadedly connected with the external gas pipeline through a metal hose, the center lance nozzle (6.3) is concentrically welded with the stable combustion device (8), the center lance nozzle (6.3) is provided with 1-3 rows of oblique nozzles, the number of the oblique nozzles in each row is 4-16, the oblique nozzles are uniformly distributed along the circumference of the center lance (6), the diameter of the oblique nozzles is 2-10 mm, the center line of the oblique nozzles of the center lance nozzle (6.3) forms an angle A with the center line of the center lance (6), and the angle A is 20-70°.

5. A gas low NOx duct burner according to claim 1, characterized in that: The inner layer lance (7) comprises an inner layer lance barrel (7.1) and an inner layer lance nozzle (7.2) arranged on the inner layer lance barrel (7.1), the lance barrel (7.1) is welded on a circular partition disc (3.3) located at the inner layer gas chamber (3.1) and uniformly distributed along the circumference outside the center lance (6), and the inner layer lance nozzle (7.2) is arranged at an inclination angle B to the center of the burner.

6. A gas low NOx duct burner according to claim 1, characterized in that: The stable combustion device (8) comprises an axial cyclone vane (8.1) and an outer ring (8.2), the axial cyclone vane (8.1) is arranged in a fan shape to form a swirling gas flow and is welded and fixed on the outer ring (8.2).

7. A gas low NOx duct burner according to claim 1, characterized in that: The outer layer lance (9) comprises an outer layer lance barrel (9.1) and an outer layer lance nozzle (9.2) arranged on the outer layer lance barrel (9.1), the outer layer lance barrel (9.1) is welded on a circular partition disc (3.3) located at the outer layer gas chamber (3.2) and uniformly distributed along the circumference outside the inner layer lance (7), the outer layer lance nozzle (9.2) is provided with 1-3 rows of nozzles, the number of the nozzles in each row is 1-12, the nozzles are uniformly distributed along the circumference, the diameter of the nozzles is 2-10 mm, the number of the nozzles is determined according to the gas flow and the gas pressure, the radial distance between the outer layer lance nozzle (9.2) and the outer edge of the tapered tower-shaped fire barrel (10) is 10-30 mm, and the distance M between the outer layer lance nozzle (9.2) and the end surface of the tapered tower-shaped fire barrel (10) is 20-50 mm.

8. A gas low NOx duct burner according to claim 1, characterized in that: The conical head tower-shaped fire barrel (10) comprises a conical pipe transition pipe (10.1), a stable combustion expansion cone transition pipe (10.2) and a cooling expansion cone transition pipe (10.3) welded together in sequence, one end of the conical pipe transition pipe (10.1) is connected with the outer ring (8.2) of the stable combustion device (8) through concentric welding, the taper C of the conical pipe transition pipe (10.1) is 90-150°; at least two circles of combustion assisting holes (a) are arranged on the taper surface of the stable combustion expansion cone transition pipe (10.2), the number of the holes in each circle is 8-30, the hole diameter is 10-50 mm, and the combustion assisting holes in each circle are arranged at intervals; at least one circle of cooling holes (b) is arranged on the circumference of the cooling expansion cone transition pipe (10.3), the cooling holes are arranged at intervals, the number is 8-30, and the hole diameter is 10-50 mm.

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