CN214745722U - Fuel grading low NOx gas burner - Google Patents

Abstract

The utility model discloses a hierarchical low NOx gas burner of fuel, mainly by the fire pan brick, central main air gun, the pilot lamp, the air regulating valve, the supplementary air gun of annular constitutes, all install in the combustor main part above the part, the inboard venturi flame path structural style that designs into earlier and expands after receiving of fire pan brick, fire pan brick lateral surface sets up eight tube seats, during the equipment, central main air gun inserts and installs flame path central point and puts, the tube seat position is installed in the supplementary air gun of annular insertion, the fuel definition that central main air gun provided is first order fuel, the fuel definition that the supplementary air gun of annular provided is second grade fuel. The utility model provides a fuel grading low NOx gas burner, which realizes fuel grading and proportion adjustment; sectional combustion and flame stabilization; the design idea of low nitrogen emission and convenient disassembly and assembly reduces the surface temperature of flame, effectively reduces the generation of thermal NOx, and simultaneously meets the requirements of NOx and CO emission.

Description

Fuel grading low NOx gas burner

Technical Field

The utility model relates to a combustion apparatus technical field particularly, relates to a hierarchical low NOx gas burner of fuel.

Background

With the promulgation and implementation of the emission standard of pollutants for the petroleum refining industry (GB31570-20015) and the emission standard of pollutants for the petrochemical industry (GB31571-20015), the orderly promotion of the environmental protection and reconstruction project of heating furnace combustion equipment in various industries such as the petrochemical industry, the coal chemical industry, the industrial furnace kiln, the boiler and the like, the information feedback from the market, and the low-nitrogen burners of various forms are applied in various industries.

When the burner is used, because the conditions of the combustion system are different, the same low-nitrogen burner can often generate different emission effects under the conditions of the same fuel and different hearth temperatures; different emissions results can be produced even under different fuel conditions in the same furnace. The method mainly shows that when the temperature of a hearth is lower than 650 ℃, CO emission data can exceed 50mg/Nm3, the CO emission data exceeds the target requirement of a modification project, and when the temperature of the hearth is higher than 650 ℃, NOx exceeds the standard; even when the fuel with low calorific value is discharged, the fuel with high calorific value is discharged but is unqualified. This is due to the fact that the burner structure is relatively fixed after the burner structure is selected and during use due to frequent changes in combustion conditions.

SUMMERY OF THE UTILITY MODEL

To the problem among the correlation technique, the utility model provides a hierarchical low NOx gas burner of fuel solves current combustor structure relatively fixed, and when using, the combustion environment in the combustor changes often, leads to the problem that nitrogen oxide pollutant discharge exceeds standard.

In order to achieve the technical purpose, the technical scheme of the utility model is as follows:

designing a fuel grading low NOx gas burner, which comprises a burner main body, wherein the top end of the burner main body is connected with a fire pan brick, the bottom end of the burner main body is fixedly provided with a main body bottom plate, the center of the bottom surface of the main body bottom plate is provided with a central main air gun sleeve hole, the periphery of the bottom surface of the main body bottom plate is provided with a pilot burner mounting hole, the bottom end of the main body bottom plate is connected with an annular auxiliary air gun, the annular auxiliary air gun is connected with a collecting pipe, and the collecting pipe is fixed on the bottom surface of the main body bottom plate; a cavity is arranged in the burner main body, a central main air gun and a pilot burner are arranged in the cavity of the burner main body, the central main air gun penetrating through a sleeve hole of the central main air gun is connected with the collecting pipe through a metal hose, the pilot burner penetrating through a mounting hole of the pilot burner is connected with the collecting pipe, and an air regulating valve is arranged on the side wall of the bottom end of the burner main body; the burner main part sets firmly on the bottom plate of heating furnace, the center of fire pan brick is provided with the flame path, the flame path is the venturi structure, the lateral surface of fire pan brick is provided with a plurality of tube seat, the top of the supplementary air gun of annular is provided with assists the shower nozzle, it penetrates the tube seat to assist the shower nozzle, the top of the main air gun in center is provided with main shower nozzle, main shower nozzle penetrates the flame path, be provided with the flame stabilizing dish between burner main part, the flame path, the bottom of the main air gun in center still is provided with burning interstage distributing valve, wherein, burning interstage distributing valve is used for adjusting the follow the collecting pipe distributes to center main air gun fuel ratio.

Furthermore, eight pipe grooves are uniformly formed in the outer side face of the fire basin brick.

Furthermore, a plurality of spray holes are uniformly arranged on the main spray head.

Further, the supplementary air gun of annular is including rising gun barrel two, it is in to assist the shower nozzle setting the top of rising gun barrel two, assist the shower nozzle, rise and be detachable connection between the gun barrel two.

Further, the height of the main spray head is larger than that of the auxiliary spray head.

Further, a fuel inlet joint is arranged between the annular auxiliary air gun and the collecting pipe.

Further, the burner main body is fixed on a bottom plate of the heating furnace through a mounting top flange.

Furthermore, a central main air gun sleeve is arranged on the outer wall of the central main air gun.

Furthermore, an annular auxiliary air gun sleeve is arranged on the outer wall of the annular auxiliary air gun.

Further, the flame stabilizing disc is of an inner cone-shaped structure.

The utility model has the advantages that: the fuel grading adjustable NOx gas burner is suitable for bottom burning or side burning circular flame, and can meet the requirement of low nitrogen emission under the conditions of various natural gas, artificial gas, liquefied gas or biomass gas fuels. In structural design, the classification and combination design of the central main air gun and the annular auxiliary air gun is adopted, so that the classification and proportion of fuel are adjustable, the discharge index is controllable, the central main air gun with a single gun barrel and the annular auxiliary air guns with multiple gun barrels are convenient to disassemble and assemble, the independent online replacement can be realized, and the characteristics of convenience in inspection and maintenance are realized; the Venturi structure of the fire channel of the fire basin brick and the design of the flame stabilizing disc on the main body are also favorable for promoting the mixing and diffusion of combustion air and fuel gas and stabilizing fire, and the problem of discharge of fuels with different hearth temperatures and different heat values is solved by better matching; through the combination of the fuel classification of the main and auxiliary gas guns and the fire pan, a rigid and stable columnar flame is formed, the surface area of the flame is increased, the surface temperature of the flame is reduced, the generation of thermal NOx is inhibited, and the low NOx emission of combustion flue gas is realized; the pilot burner can prevent the flame of the main burner and the auxiliary burner of the burner from being extinguished, and the burner can be quickly reignited when the pilot burner is extinguished.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic structural view of a fuel staged low NOx gas burner in accordance with an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a burner body in a fuel staged low NOx gas burner according to an embodiment of the present invention;

FIG. 3 is a top view of a burner body in a fuel staged low NOx gas burner according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a central primary air gun in a fuel staged low NOx gas burner, according to an embodiment of the present invention;

FIG. 5 is a schematic view of an annular auxiliary gas gun in a fuel staging low NOx gas burner according to an embodiment of the present invention;

FIG. 6 is a perspective view of a fire pan brick in a fuel staged low NOx gas burner according to an embodiment of the present invention;

FIG. 7 is a top view of a fire pan brick in a fuel staged low NOx gas burner according to an embodiment of the present invention;

FIG. 8 is a cross-sectional view of a fire pan brick in a fuel staged low NOx gas burner according to an embodiment of the present invention;

fig. 9 is a perspective view of a fuel staged low NOx gas burner in accordance with an embodiment of the present invention;

FIG. 10 is a front view of a fuel staged low NOx gas burner according to an embodiment of the present invention;

in the figure: 1. a fire pan brick; 11. a flame path; 12. a pipe groove; 2. a burner body; 21. a flame stabilizing disc; 22. a main body outer cylinder; 23. a fire pan base; 24. mounting a top flange; 25. a central main air gun sleeve; 26. a rhombic steel plate net inner cylinder; 27. insulating the inner lining; 28. an annular auxiliary air gun sleeve; 29. a middle partition plate; 210. a main body bottom plate; 211. a steel screen retainer ring; 212. hoisting the hanging opening; 213. an ignition hole; 214. a Changming lamp mounting hole; 215. mounting bolts for the pilot lights; 216. a hoop is installed on the annular auxiliary air gun; 217. an annular auxiliary air gun mounting bolt; 218. a fire observation hole; 3. a central main air gun; 31. a main spray head; 32. lifting the gun barrel I; 33. a first flange; 34. a combustion interstage distribution valve; 35. a first combustion grading joint; 4. a beacon light; 5. an air regulating valve; 6. an annular auxiliary air gun; 61. an auxiliary spray head; 63. a lower positioning block; 62. an upper positioning block; 64. lifting the second gun barrel; 65. a manifold; 66. a fuel inlet fitting; 67. a second fuel grading joint; 68. a pipe flange; 7. and a first metal hose.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art all belong to the protection scope of the present invention.

As shown in fig. 1-8, according to the embodiment of the present invention, a fuel classification low NOx gas burner includes a burner body 2, and is characterized in that a fire pan brick 1 is connected to a top end of the burner body 2, a body bottom plate 210 is fixedly arranged at a bottom end of the burner body 2, a center main air gun sleeve hole is arranged at a bottom center of the body bottom plate 210, a long bright lamp mounting hole 214 is arranged at a bottom periphery of the body bottom plate 210, an annular auxiliary air gun 6 is connected to a bottom end of the body bottom plate 210, the annular auxiliary air gun 6 is connected to a collecting pipe 65, and the collecting pipe 65 is fixed on the bottom surface of the body bottom plate 210; a cavity is arranged in the burner main body 2, a central main air gun 3 and an incandescent lamp 4 are arranged in the cavity of the burner main body 2, the central main air gun 3 penetrating through a sleeve hole of the central main air gun is connected with the collecting pipe 65 through a metal hose I7, the incandescent lamp 4 penetrating through a mounting hole 214 of the incandescent lamp is connected with the collecting pipe 65, and an air adjusting valve 5 is arranged on the side wall of the bottom end of the burner main body 2; the burner body 2 is fixedly arranged on a bottom plate of a heating furnace, a flame path 11 is arranged in the center of the fire pan brick 1, the flame path 11 is of a Venturi tube structure, a plurality of tube slots 12 are arranged on the outer side surface of the fire pan brick 1, an auxiliary spray head 61 is arranged at the top end of the annular auxiliary air gun 6, the auxiliary spray head 61 penetrates into the tube slots 12, a main spray head 31 is arranged at the top end of the central main air gun 3, the main spray head 31 penetrates into the flame path 11, a flame stabilizing disc 21 is arranged between the burner body 2 and the flame path 11, and a combustion interstage distribution valve 34 is further arranged at the bottom end of the central main air gun 3, wherein the combustion interstage distribution valve 34 is used for adjusting the proportion of fuel distributed to the central main air gun 3 from the collecting pipe 65.

As shown in fig. 6, in this embodiment, eight pipe slots 12 are uniformly formed on the outer side surface of the firebox brick 1.

As shown in fig. 1 and 4, in this embodiment, a plurality of spray holes are uniformly formed in the main nozzle 31, and the main nozzle 31 adopts a multi-spray-hole multi-angle design, so that the primary flame is divided into a larger number of small flames, the secondary gas is more uniformly ignited, the flame is effectively prevented from being too concentrated, the surface temperature of the flame is reduced, and the generation of thermal nitrogen oxides is inhibited.

As shown in fig. 1 and 5, in this embodiment, the annular auxiliary air gun 6 includes a second ascending barrel 64, the auxiliary spray head 61 is disposed at the top end of the second ascending barrel 64, and the auxiliary spray head 61 and the second ascending barrel 64 are detachably connected.

As shown in fig. 1, 4 and 5, in the present embodiment, the height of the main nozzle 31 is greater than that of the auxiliary nozzle 61, and due to the height difference between the auxiliary nozzle 61 and the main nozzle 31, the injected primary and secondary fuel gases realize staged combustion of fuel, organize specific fuel staging and staged combustion flame shapes, and form a more balanced flame temperature field distribution, thereby avoiding local high temperature.

As shown in fig. 1 and 5, in the present embodiment, a fuel inlet joint 66 is provided between the annular auxiliary air gun 6 and the manifold 65.

As shown in fig. 1 and 2, in the present embodiment, the burner body 2 is fixed to the floor of the heating furnace by a mounting top flange 24.

As shown in fig. 1, 2 and 4, in the present embodiment, a central main air gun sleeve 25 is provided on the outer wall of the central main air gun 3.

As shown in fig. 1 and 2, in the present embodiment, an annular auxiliary air gun sleeve 28 is disposed on an outer wall of the annular auxiliary air gun 6.

As shown in fig. 1 and 2, in the present embodiment, the flame stabilizing disc 21 has an inner cone structure.

In order to facilitate further understanding of the above technical solutions, the working principle thereof will now be explained:

as shown in fig. 1 to 10, the fuel classification low NOx gas burner is mainly composed of a fire pan brick 1, a central main air gun 3, a pilot burner 4, an air damper 5 and an annular auxiliary air gun 6, which are all mounted on a burner main body 2. The inner side of the fire basin brick 1 is designed into a Venturi flue structure form of firstly contracting and then expanding, eight pipe grooves 12 are formed in the outer side face of the fire basin brick 1, during assembly, a central main air gun 3 is inserted into and installed in the central position of a flue 11, and an annular auxiliary air gun 6 is inserted into and installed in the pipe grooves 12; the fuel supplied by the central primary air gun 3 is defined as the first stage fuel and the fuel supplied by the annular auxiliary air gun 6 is defined as the second stage fuel.

The central main air gun 3 mainly comprises a main nozzle 31, a first ascending gun pipe 32, a first flange 33, a combustion interstage distribution valve 34 and a fuel staging joint 35, wherein primary fuel gas sprayed out of the main nozzle 31 is mixed with auxiliary fuel air in a flame path 11 and then is ignited by an pilot burner 4, generated primary flame ignites secondary fuel gas to generate secondary flame, the fuel proportion of the central main air gun 3 distributed from a collecting pipe 65 is adjusted through the combustion interstage distribution valve 34, and emission control of fuels with different heat values and different hearth temperatures is achieved. Due to the multi-orifice and multi-angle design of the main nozzle 31, the primary flame is divided into a larger number of small flames, so that the secondary gas is more uniformly ignited, the phenomenon that the flame is too concentrated is effectively avoided, the surface temperature of the flame is reduced, and the generation of thermal nitrogen oxide is inhibited.

The annular auxiliary air gun 6 mainly comprises an auxiliary spray nozzle 61, a lower positioning block 63, an upper positioning block 62, a second ascending gun barrel 64, a collecting pipe 65, a fuel inlet joint 66, a fuel grading joint 67 and a pipe flange 68, the annular auxiliary air gun 6 is generally provided with eight or four groups of uniformly distributed second ascending gun barrels 64, wherein secondary fuel sprayed by the auxiliary spray nozzle 61 is ignited by primary divided flame sprayed by the central main air gun 3 to form uniformly ignited secondary divided flame, the sprayed primary and secondary gas realizes the sectional combustion of the fuel due to the height difference between the auxiliary spray nozzle 61 of the annular auxiliary air gun 6 and the main spray nozzle 31 of the central main air gun 3, specific fuel grading and sectional combustion flame shapes are organized, the distribution of the temperature field of the formed flame is more balanced, local high temperature is avoided, and meanwhile, the graded fuel sprayed by a plurality of spray holes of the main spray nozzle and the auxiliary spray nozzle is more uniformly mixed with combustion-supporting air, the combustion is more sufficient, thereby achieving the energy-saving purpose of simultaneously reducing the emission of NOx and CO.

The central main air gun 3 and the annular auxiliary air gun 6 share the collecting pipe 65 and the gas inlet joint 66, fuel of the central main air gun 3 is graded from the inside of the collecting pipe 65, and each gun barrel of the graded main air gun and each gun barrel of the graded auxiliary air gun can be independently replaced on line, so that the gas gun has the characteristic of convenience in inspection and maintenance.

The design of the inner conical flame stabilizing disc 21 in the burner body 2, the flame stabilizing block is arranged outside the conical flame stabilizing disc 21, and the primary flame stabilization of the central main air gun 3 is realized by combining the venturi structure of the flame path 11 and the negative pressure vortex area generated by the combustion-supporting air flow in the flame path 11.

In the assembling process, the burner body 2 is welded with the air adjusting butterfly valve into a whole through a side wall opening, and is fixed on a bottom plate or a side plate of a heating furnace through a mounting top flange 24, a bolt and a nut, an air duct is connected with the burner air adjusting butterfly valve, the fire pan brick 1 is placed on a fire pan base 23, the fire pan brick 1 is positioned and fixed through an annular auxiliary air gun sleeve 28 and a body outer cylinder 22, and after the fire pan brick 1 is in place, a gap between the fire pan brick 1 and a furnace bottom lining is filled with refractory filler; respectively inserting the pilot burner 4 and the central main air gun 3 into the pilot burner mounting hole 214 and the central main air gun sleeve hole, and respectively fixing the central main air gun 3 and the pilot burner 4 by a first flange 31 and a second flange and fastening by bolts and nuts; inserting the annular auxiliary air gun 6 into the annular auxiliary air gun sleeve 25 on the main body, and fixing the collecting pipe 65 on the main body bottom plate 210 by using a hoop, a bolt and a nut; the inner stepped joints of the central main air gun 3 and the annular auxiliary air gun 6 are connected by metal hoses. And finally, respectively connecting the gas inlet joints of the pilot burner 4 and the annular auxiliary gas gun 6 with respective interfaces on a fuel pipeline by using metal hoses to finish the connection and installation of the fuel pipeline of the burner.

In the working process, the ignition adopts a two-stage safe ignition mode of firstly igniting the pilot burner 4 and then igniting the main flame by the pilot burner 4, on one hand, combustion-supporting air enters the flame path 11 through the air adjusting butterfly valve and the inner cavity of the burner main body 2, and combustion-supporting air flows pass through the venturi structure flame path 11 and the main body upper flame stabilizing disc 21 to generate a negative pressure vortex area, so that the mixing and diffusion of the combustion-supporting air and fuel gas are promoted, and the primary flame stabilization of the central main air gun 3 is realized. On the other hand, the fuel gas enters a collecting pipe 65 in the annular auxiliary air gun 6 from a fuel pipeline interface, a part of the fuel gas enters the central main air gun 3 through a first combustion grading joint 35 and a grading metal hose, is sprayed out from a main nozzle 31 of the central main air gun 3 to be primary fuel gas, is mixed with combustion-supporting air in a fire pan and is ignited by a pilot burner 4; the other part of the gas is distributed to a plurality of branched ascending gun pipes 64 of the annular auxiliary gas gun 6 from the collecting pipe 65, is sprayed out from the auxiliary spray head 61 and is secondary gas, and is ignited by primary gas flame. The fuel distribution proportion of the main air gun 3 and the annular auxiliary air gun 6 in the control center is adjusted by operating the interstage distribution valve, so that the emission control of fuels with different heat values and different hearth temperatures is realized. Due to the height difference between the auxiliary spray nozzle 61 and the main spray nozzle 31, staged primary and secondary fuel gas can be combusted in the furnace in a segmented manner.

The grading and multi-nozzle design of the fuel enables the fuel and the combustion air to be uniformly mixed, the combustion flame is divided into a large number of small flames, the graded fuel is uniform in ignition and more sufficient in combustion, the flame is prevented from being excessively concentrated, the surface temperature of the flame is reduced, and the generation of thermal nitrogen oxides is inhibited; the flame body formed by the sectional combustion approaches to a column shape, so that local high temperature is avoided, the temperature field distribution is more exquisite and balanced, and the generation level of nitrogen oxide is lower; the venturi structure of the flame path 11 in the fire basin brick 1 and the design of the flame stabilizing disc 21 on the burner main body 2 are also beneficial to promoting the mixing and diffusion of combustion air and fuel gas and stabilizing fire. Meanwhile, the negative pressure generated by the secondary gas kinetic energy also sucks the smoke in the furnace to flow back to participate in mixed combustion, reduces the surface temperature of flame and inhibits the generation of nitrogen oxides.

The design of pipe flange 68 in the supplementary air gun 6 of annular still makes each barrel easy dismounting, and hierarchical owner, supplementary air gun can realize changing alone online, have the characteristics of examining easy maintenance.

In conclusion, the combustor integrates a plurality of innovation points, and realizes fuel classification and proportion adjustment; sectional combustion and flame stabilization; the design idea of low nitrogen emission and convenient disassembly and assembly reduces the surface temperature of flame, effectively reduces the generation of thermal NOx, and achieves the aim of simultaneously meeting the emission of NOx and CO. The better matching of the burner solves the problem of discharging fuels with different hearth temperatures and different heat values, and realizes the effects of fuel grading adjustability and low NOx gas discharge.

In the description of the present invention, it should be understood that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.

In the present invention, unless otherwise explicitly specified or limited, for example, it may be fixedly connected, detachably connected, or integrated; can be mechanically or electrically connected; they may be directly connected or indirectly connected through an intermediate medium, and may be connected through the inside of two elements or in an interaction relationship between two elements, unless otherwise specifically defined, and the specific meaning of the above terms in the present invention will be understood by those skilled in the art according to specific situations.

It is noted that, in this document, relational terms such as "component" and "element" and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (10)

1. The fuel grading low-NOx gas burner comprises a burner main body (2), and is characterized in that the top end of the burner main body (2) is connected with a fire pan brick (1), the bottom end of the burner main body (2) is fixedly provided with a main body bottom plate (210), the center of the bottom surface of the main body bottom plate (210) is provided with a central main gas gun sleeve hole, the periphery of the bottom surface of the main body bottom plate (210) is provided with a pilot burner mounting hole (214), the bottom end of the main body bottom plate (210) is connected with an annular auxiliary gas gun (6), the annular auxiliary gas gun (6) is connected with a collecting pipe (65), and the collecting pipe (65) is fixed on the bottom surface of the main body bottom plate (210); a cavity is formed in the burner main body (2), a central main air gun (3) and an incandescent lamp (4) are arranged in the cavity of the burner main body (2), the central main air gun (3) penetrating through a sleeve hole of the central main air gun is connected with the collecting pipe (65) through a metal hose I (7), the incandescent lamp (4) penetrating through a mounting hole (214) of the incandescent lamp is connected with the collecting pipe (65), and an air adjusting valve (5) is arranged on the side wall of the bottom end of the burner main body (2); the burner body (2) is fixedly arranged on a bottom plate of the heating furnace, a flame path (11) is arranged at the center of the fire basin brick (1), the flame path (11) is of a Venturi tube structure, the outer side surface of the fire basin brick (1) is provided with a plurality of pipe grooves (12), the top end of the annular auxiliary air gun (6) is provided with an auxiliary spray head (61), the auxiliary spray head (61) penetrates into the pipe groove (12), the top end of the central main air gun (3) is provided with a main spray head (31), the main spray head (31) penetrates into the flame path (11), a flame stabilizing disc (21) is arranged between the burner main body (2) and the flame path (11), the flame stabilizing disc (21) is positioned at the reducing part of the Venturi tube structure, the bottom end of the central main air gun (3) is also provided with a combustion interstage distribution valve (34), wherein the inter-combustion stage distribution valve (34) is used to adjust the proportion of fuel distributed from the collecting pipe (65) to the central main air gun (3).

2. A fuel staged low NOx gas burner according to claim 1, characterized in that the outer side of the firebox brick (1) is uniformly provided with eight of said tube slots (12).

3. A fuel staged low NOx gas burner as claimed in claim 1, wherein said main nozzle (31) is provided with a plurality of nozzle holes uniformly.

4. A fuel staged low NOx gas burner according to claim 1, wherein the annular auxiliary air lance (6) comprises a second lance riser (64), the auxiliary lance (61) is disposed at the top end of the second lance riser (64), and the auxiliary lance (61) and the second lance riser (64) are detachably connected.

5. A fuel staged low NOx gas burner as claimed in claim 1, characterized in that the height of the main nozzles (31) is greater than the height of the auxiliary nozzles (61).

6. A fuel staged low NOx gas burner according to claim 1, characterised in that a fuel inlet connection (66) is provided between the annular auxiliary gas lance (6) and the manifold (65).

7. A fuel staged low NOx gas burner according to claim 1, wherein the burner body (2) is secured to the floor of the furnace by a mounting top flange (24).

8. A fuel staged low NOx gas burner according to claim 1, characterised in that the outer wall of the central primary air gun (3) is provided with a central primary air gun sleeve (25).

9. A fuel staged low NOx gas burner according to claim 1, characterized in that an annular auxiliary air lance sleeve (28) is provided on the outer wall of the annular auxiliary air lance (6).

10. A fuel-staged low NOx gas burner as claimed in claim 1, characterized in that the flame stabilizing discs (21) are of an inwardly tapered configuration.

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