CN218672163U - Low-heat-value low-NOx gas burner with small throat - Google Patents

Abstract

The utility model discloses a low calorific value low NOx gas burner of little choke relates to gas burner technical field. Including the central tuber pipe, central fuel pipe, outer gas spray gun and the combustor throat of from inside to outside coaxial setting, the inside central wind passageway that is provided with of central tuber pipe, the one end of central tuber pipe is provided with central tuber pipe terminal surface, and central tuber pipe terminal surface is provided with the flame stabilization device, and the inside central fuel passageway that is provided with of central fuel pipe, the one end of central fuel pipe is provided with central fuel pipe terminal surface, and central gas nozzle subassembly is installed to central fuel pipe terminal surface. The utility model discloses the little throat of combustor is more convenient for use in the little transformation project of combustor mounting hole. The built-in gas spray gun is arranged in the outer ring cyclone air channel, the outer gas spray gun is arranged in the outer ring air direct current channel, the combustor is compact in structure, and the throat opening of the combustor is small.

Description

Low-heat-value low-NOx gas burner with small throat

Technical Field

The utility model relates to a gas burner technical field specifically is a low calorific value low NOx gas burner of little choke.

Background

Some low-heat value gas burners are available in the market at present, but because the pressure of industrial combustible waste gas is low, the gas quantity is large under the same output, and a gas channel is generally independently arranged to the end face of a throat opening of the burner in the burner and is not overlapped with a channel of combustion-supporting air in space, namely the gas channel is basically not arranged in the combustion-supporting air channel, so that the throat opening of the burner is large. For the established transformation project of the burner mounting hole, the problems that the throat of the burner is large, the burner cannot be installed in the hole and the tube needs to be moved are existed, and the project cost is increased and the construction quantity is large. In addition, for low-heating-value gas in the market, a low-speed combustion stabilizing area with a large area is often arranged for combustion stabilizing, and space is wasted.

The utility model discloses innovative low heat value gas burner structure arranges outer gas gun passageway, interior gas gun passageway in air duct, makes low heat value burner compact structure, and the throat of combustor is less, and the coupling center surely fires low-nitrogen combustion techniques such as technique, fractional combustion, dense-dilute combustion, makes the steady burning performance of combustor good, and NOx's emission is low.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a low calorific value of little choke hangs down NOx gas burner to solve the problem that proposes among the above-mentioned background art.

In order to achieve the above object, the utility model provides a following technical scheme: a small-throat-opening low-calorific-value low-NOx gas burner comprises a central air pipe, a central fuel pipe, an outer gas spray gun and a burner throat, wherein the central air pipe, the central fuel pipe, the outer gas spray gun and the burner throat are coaxially arranged from inside to outside, a central air channel is arranged inside the central air pipe, a central air pipe end face is arranged at one end of the central air pipe, a flame stabilizing device is arranged at the end face of the central air pipe, a central fuel channel is arranged inside the central fuel pipe, a central gas nozzle assembly is arranged at the end face of the central fuel pipe, an outer ring cyclone air channel is formed between the central fuel pipe and the outer gas spray gun, an outer ring fuel pipe direct-flow air channel is formed between the burner throat and the outer gas spray gun, a built-in gas spray gun is fixedly connected to the central fuel pipe, the built-in gas spray gun is located inside the outer ring cyclone air channel, and an outer gas spray gun is installed at the end face of the outer gas spray gun.

Furthermore, the flame stabilizing device comprises a flame stabilizing disc and a flame stabilizing plate, the flame stabilizing disc is fixed on the end face of the central air pipe, the inner portion of the flame stabilizing disc is fixedly connected with an inner cylinder of the flame stabilizing disc, the outer wall of the inner cylinder of the flame stabilizing disc is fixedly connected with a small swirl blade, the flame stabilizing plate is fixed on the end face of the outer ring swirl air channel, and a plurality of cooling air holes are formed in the end face of the flame stabilizing plate.

Furthermore, the central gas nozzle assembly comprises an inner gas distribution plate fixed on the end surface of the central fuel pipe, and a plurality of central gas nozzles are circumferentially arranged on the end surface of the inner gas distribution plate.

Further, the central gas nozzle is one of trapezoidal and circular in shape, and the central gas nozzle is annularly arranged on the inner gas distribution plate in multiple layers. The central gas nozzle comprises a plurality of trapezoidal central gas nozzles which are arranged on the end face of the inner gas distribution plate in a circumferential manner, and a circular central gas nozzle is arranged between two adjacent trapezoidal central gas nozzles.

Furthermore, the inner gas distribution plate is in a horn-shaped structure which is reduced towards the interior of the central fuel channel, and the angle between the inner wall of the inner gas distribution plate and the axis of the central fuel channel is 0-60 degrees.

Furthermore, the built-in gas spray gun comprises an inner gas channel pipe communicated with the central fuel pipe, and the other end of the inner gas channel pipe is fixedly connected with an inner gas spray head.

Further, the inner gas burner is oriented tangentially to the circumference formed by the plurality of inner gas burners.

Furthermore, the outer gas spray nozzle comprises a plurality of outer gas spray nozzles I and a plurality of outer gas spray nozzles II, the spray nozzles of the outer gas spray nozzles I face the outer ring direct-current air channel region, the spray nozzle directions of the outer gas spray nozzles II are two, one spray nozzle faces the outer ring direct-current air channel region and is provided with an axial direction facing the forward gas spray nozzles to the direct-current air channel, and an outer gas gun channel is arranged outside the outer gas spray gun to surround the outer gas spray gun.

Furthermore, a central cylinder is arranged in the outer ring rotational flow air channel, one end of the central cylinder is provided with a central cylinder end face, and a plurality of rotational flow blades are fixedly connected between the central cylinder end face and the inner wall of the central fuel pipe.

Compared with the prior art, the beneficial effects of the utility model are that:

1. the small throat of the burner is more convenient to use in the reconstruction project with small mounting holes of the burner. The built-in gas spray gun is arranged in the outer ring cyclone air channel, the outer gas spray gun is arranged in the outer ring air direct current channel, the combustor is compact in structure, and the throat opening of the combustor is small.

2. The combustor has good stable combustion performance. The central gas nozzle enables the central gas to be obliquely sprayed into the combustor at an angle of 0-60 degrees, and a flame stabilizing disc is arranged in the central air channel to stabilize central flame; a flame stabilizing plate is arranged on the outer side of the central gas nozzle to protect the central flame; and the inner gas guns are arranged annularly and are connected with inner and outer flames, so that the flame continuity is good, and the stable combustion performance of the combustor is good.

3. The swirl strength of the combustion-supporting air is high, the gas is radially sprayed to penetrate through an air layer, the range is wide, and the NOx emission is low. The swirl strength of the combustion-supporting air is high, so that the gas and the air are mixed more uniformly, and the emission of NOx is reduced; the technology of coupled thick and thin combustion and staged combustion enables the center of the combustor to be thick and the periphery to be thin, and the emission of NOx is reduced. And the injection range of the fuel gas is wide, so that the flame fullness of fuel combustion is high, a local high-temperature area is reduced, and the emission of NOx is further reduced.

4. The nozzle of the external gas gun axially extends out of the end surface of the outlet of the throat so as to facilitate the internal entrainment of the flue gas.

The utility model discloses a structural design of innovative low heat value combustor sets up built-in gas spray gun in outer lane whirl wind passageway, and outer gas spray gun sets up in outer lane wind DC passage, makes the compact structure of combustor, and the larynx mouth is less, and the coupling center surely fires low nitrogen combustion techniques such as technique, fractional combustion, dense and weak burning, makes the steady burning performance of combustor good, and NOx's emission is low. The burner has great advantages in the project of reforming the burner with a small throat, and can avoid moving the tube in the burner area, thereby greatly reducing the workload of reforming.

Drawings

Fig. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic view of a half-section structure of the present invention;

FIG. 3 is a schematic view of the annular arrangement of the internal combustion gas injection ports of the present invention;

FIG. 4 is a schematic view of the flame holder and the central gas nozzle assembly of the present invention;

fig. 5 is a schematic view of the structure of the small swirl vane of the present invention.

In the figure: 1. a flame stabilizing device; 11. a flame stabilizing disc; 111. an inner cylinder of a flame stabilizing disc; 112. a small swirl vane; 12. a flame stabilizing plate; 121. cooling air holes; 2. a combustion-supporting air passage; 21. a central wind channel; 211. a central air duct; 212. the end surface of the central air pipe; 22. an outer ring air channel; 221. an outer ring rotational flow air channel; 222. an outer ring direct current air channel; 3. a central fuel passage; 31. a central fuel tube; 32. a central fuel tube end face; 4. a central gas nozzle assembly; 41. an inner gas distribution plate; 42. a central gas nozzle; 421. a trapezoidal central gas nozzle; 422. a circular central gas nozzle; 4221. an internal-spraying gas nozzle; 5. a gas spray gun is arranged inside; 51. an inner combustion gas passage; 52. an inner gas nozzle; 6. a central barrel; 61. a central barrel end face; 7. a swirl vane; 8. an external gas spray gun; 81. an outer gas burner; 811. an outer gas nozzle I; 812. an outer gas nozzle II; 8121. a forward gas nozzle; 82. an external gas gun channel; 9. a burner throat; 91. the end surface of the burner throat.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the 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 without creative work belong to the protection scope of the present invention.

It should be noted that, in the description of the present invention, the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of description and simplification of the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

Further, it will be appreciated that the dimensions of the various elements shown in the figures are not drawn to scale, for ease of description, and that the thickness or width of some layers may be exaggerated relative to other layers, for example.

It should be noted that like reference numerals and letters refer to like items in the following figures, and thus, once an item is defined or illustrated in one of the figures, it will not need to be further discussed or illustrated in detail in the description of the figures that follows.

As shown in fig. 1-5, the utility model provides a technical solution: a low-calorific-value and low-NOx gas burner with a small throat comprises a central air pipe 211, a central fuel pipe 31, an outer gas spray gun 8 and a burner throat 9 which are coaxially arranged from inside to outside, wherein a central air channel 21 is arranged inside the central air pipe 211, a central air pipe end face 212 is arranged at one end of the central air pipe 211, a flame stabilizing device 1 is arranged on the central air pipe end face 212, a central fuel channel 3 is arranged inside the central fuel pipe 31, a central fuel pipe end face 32 is arranged at one end of the central fuel pipe 31, a central gas nozzle assembly 4 is installed on the central fuel pipe end face 32, an outer ring swirl air channel 221 is formed between the central fuel pipe 31 and the outer gas spray gun 8, an outer ring straight-flow air channel 222 is formed between the burner throat 9 and the outer gas spray gun 8, a built-in gas spray gun 5 is fixedly connected to the central fuel pipe 31, the built-in gas spray gun 5 is positioned inside the outer ring swirl air channel 221, an outer gas spray gun 8 is provided with an outer gas spray nozzle 81, the central air pipe 211, the central air pipe 31, the outer ring 31, the central air pipe 31, the outer ring air spray gun 8 and the burner throat 9 are connected through a central air pipe 61, the inner wall of which is connected to the central air pipe 61, the central air pipe 61 is fixedly connected to the central air pipe 61, the central air pipe 61 is not shown in the central air pipe 61, and the central swirl tube which is arranged coaxially.

As shown in fig. 4, the flame stabilizing device 1 includes a flame stabilizing disc 11 and a flame stabilizing plate 12, the flame stabilizing disc 11 is fixed on the end surface of the central air pipe 211, the inner portion of the flame stabilizing disc 11 is fixedly connected with a flame stabilizing disc inner cylinder 111, the outer wall of the flame stabilizing disc inner cylinder 111 is fixedly connected with a small swirl vane 112, the flame stabilizing plate 12 is fixed on the end surface of the outer ring swirl air channel 221, and the end surface of the flame stabilizing plate 12 is provided with a plurality of cooling air holes 121.

As shown in fig. 4, the central gas nozzle assembly 4 includes an inner gas distribution plate 41, the inner gas distribution plate 41 is fixed on the central fuel pipe end surface 32, the end surface of the inner gas distribution plate 41 is provided with a plurality of central gas nozzles 42 in a circumferential shape, the central gas nozzles 42 may be in a trapezoidal shape, a circular shape or other shapes designed to reach the area according to the design requirement, and the central gas nozzle rings 42 are arranged on the inner gas distribution plate 41 in multiple layers. The central gas nozzle 42 includes a plurality of trapezoidal central gas nozzles 421 circumferentially disposed on the end surface of the inner gas distribution plate 41, wherein a circular central gas nozzle 422 is disposed between a group of two adjacent trapezoidal central gas nozzles 421, the inner gas distribution plate 41 is a trumpet-shaped structure that is reduced toward the inside of the central fuel passage 3, and the angle between the inner wall of the inner gas distribution plate 41 and the axis of the central fuel passage 3 is 0-60 °.

As shown in fig. 2 to 3, the internal gas spray gun 5 includes an internal gas passage pipe 51 communicating with the central fuel pipe 31, an internal gas spray head 52 is fixedly connected to the other end of the internal gas passage pipe 51, and the internal gas spray head 52 is oriented in a tangential direction of a circumference formed by the plurality of internal gas spray heads 52.

As shown in fig. 1-2, the outer gas nozzle 81 includes a plurality of outer gas nozzles 811 and a plurality of outer gas nozzles 812, the nozzle of the outer gas nozzle 811 faces the outer-ring direct-current air channel 222 area, two nozzles of the outer gas nozzles 812 face, one nozzle faces the outer-ring direct-current air channel 222 area and is provided with an axial direction facing the forward gas nozzle 8121 toward the direct-current air channel 22, and an outer gas gun channel 82 is provided outside the outer gas gun 8 to surround the outer gas gun 8.

The utility model aims at innovating the structure of low heat value gas burner aircraft nose, provide a low heat value low NOx gas burner of little choke, with outer gas gun passageway 82, internal combustion gas gun passageway arrange in air passage, make low heat value burner compact structure, the choke of combustor is less, and the coupling center surely fires low nitrogen combustion techniques such as technique, fractional combustion, dense and weak combustion, makes the steady burning performance of combustor good, NOx's emission is low.

The utility model provides a include: the burner comprises a combustion-supporting air channel 2, a flame stabilizing device 1, a central fuel channel 3, a central gas nozzle component 4, a built-in gas spray gun 5, a central cylinder 6, swirl vanes 7, an outer gas spray gun 8 and a burner throat 9, wherein the flame stabilizing device 1 comprises a flame stabilizing disc 11 and a flame stabilizing plate 12, and the combustion-supporting air channel 2 comprises a central air channel 21, an outer ring direct-current air channel 222 and an outer ring swirl air channel 221. The central air channel 21 (flame stabilizing disc 11), the central fuel channel 3 (central gas nozzle component 4), the swirl vanes 7 (internal gas spray gun 5), the central cylinder 6, the outer gas spray gun 8 and the burner throat 9 are sequentially and coaxially and symmetrically arranged from inside to outside by taking the central axis of the combustion device as the center. The internal gas spray gun 5 is arranged in the outer ring rotational flow air channel 221, the external gas spray gun 8 is arranged in the outer ring direct flow air channel 222, the burner is compact in structure, and the throat of the burner is small. And the low-nitrogen combustion technologies such as the central stable combustion technology, the staged combustion, the thick and thin combustion and the like are coupled, so that the stable combustion performance of the combustor is good, and the emission of NOx is low.

The central air channel 21 is composed of a central air pipe 211, and the end surface 212 of the central air pipe extends out of the end surface 91 of the throat of the burner;

the flame stabilizing disc 11 is arranged in the central air channel 21 and can be of a spiral flow type or a flat plate type. In this embodiment, taking a rotational flow type as an example, the flame stabilizing disc 11 is composed of a flame stabilizing disc inner cylinder 111 and a plurality of small rotational flow blades 112, the small rotational flow blades 112 are welded on the flame stabilizing disc inner cylinder 111, and in this embodiment, 12 small rotational flow blades 112 are provided.

The central fuel passage 3 is a passage formed between the central fuel pipe 31 and the central air pipe 211, and the end surface of the central fuel pipe 31 extends out of the end surface 91 of the burner throat;

the center gas nozzle assembly 4 is placed at the center fuel tube end face 32 and is comprised of an inner gas distribution plate 41 and a center gas nozzle 42. One end of the inner gas distribution plate 41 is welded with the central air pipe 211, the other end is welded with the central fuel pipe 31, the angle between the inner gas spray nozzle 52 and the axis of the burner is a, wherein a is more than or equal to 0 degree and less than 60 degrees, so that the central gas is obliquely sprayed into the burner at an angle of 0-60 degrees to stabilize the central flame. A central gas nozzle 42 is provided on the inner gas distribution plate 41, several arranged annularly. The central gas nozzle can be designed into a trapezoidal nozzle, a circular nozzle and the like according to the specific design shape of requirements, the nozzle forms in the patent drawing are two, one is the trapezoidal central gas nozzle 421, the other is the circular central gas nozzle 422 with the internal gas injection nozzle 4221, and the internal gas injection nozzle 4221 supplies fuel to the center of the combustor and is used for stabilizing the innermost central flame. In this embodiment, 10 trapezoidal central gas nozzles 421 are provided, 1 circular central gas nozzle 422 with an internal injection gas nozzle 4221 is provided, and one internal injection gas nozzle 4221 is provided on the circular central gas nozzle 422.

The swirl vanes 7 are arranged at the front end of the combustor, welded on the central fuel pipe 31 and the central cylinder 6, and arranged in a plurality of pieces according to needs, an outer ring swirl air channel 221 is formed between the central fuel pipe 31 and the central cylinder 6, and the swirl vanes 7 enable combustion-supporting air in the outer ring swirl air channel 221 to flow out in a swirl mode and have high swirl strength. In this embodiment, 12 swirl vanes 7 are provided.

The flame stabilizing plate 12 is fixed on the outer side of the central fuel pipe 31, the downstream of the swirl vanes 7, and the flame stabilizing plate 12 is provided with cooling air through holes 121 to prevent the flame stabilizing plate 12 from being burnt out. The flame stabilizing plate 12 can protect the central flame from being stable and prevent a large amount of upstream combustion-supporting air from impacting the central flame.

The built-in gas spray gun 5 is arranged in the outer ring swirling air channel 221 and is composed of an inner gas channel 51 and an inner gas spray head 52. The inner gas nozzles 52 extend out of the swirl vanes 7 and are annularly arranged to connect inner and outer flames; the inner air channel 51 is arranged in the outer ring cyclone air channel 221, and the outer ring cyclone air channel 221 and the outer ring direct-current air channel 222 work to form an outer ring air duct 22. As shown in fig. 3, in the present embodiment, 4 built-in gas lances 5 are provided.

The central cylinder 6 is an annular pipe and is arranged in the burner throat 9, the end surface 61 of the central cylinder extends out of the end surface 91 of the burner throat, and an outer ring swirl air channel 221 is formed between the central fuel pipe 31 and the central cylinder 6; an outer ring direct current air channel 222 is formed between the combustor throat 9 and the central cylinder 6.

The outer gas spray gun 8 is arranged in the outer ring direct-current air channel 222, the outer gas spray guns 8 are arranged in an annular mode, the outer gas spray gun 8 is composed of an outer gas spray gun channel 82 and an outer gas spray head 81, the outer gas spray gun channel 82 and the outer gas spray head 81 are welded, and the outer gas spray head 81 extends out of the throat end face 91 of the combustor. The outer gas nozzle 81 consists of an outer gas nozzle I811 and an outer gas nozzle II 812 which are arranged at intervals, the angle formed by the outer gas nozzle 81 and the central axial direction of the burner is b, b is more than or equal to 30 degrees and less than or equal to 90 degrees, so that the outer gas is obliquely sprayed outwards at the angle b and penetrates through an air layer to form concentrated combustion, and the spraying range of the gas is wide. The first outer gas nozzle 811 is only provided with an outward gas nozzle, and the second outer gas nozzle 812 is also provided with a forward gas nozzle 8121 besides the outward gas nozzle, so that part of the outer gas can be sprayed forward. In this embodiment, the number of the outer gas spray guns 8 is 15, wherein the number of the first outer gas spray nozzles 811 is 10, the number of the second outer gas spray nozzles 812 is 5, and the first outer gas spray nozzles 811 and the second outer gas spray nozzles 812 are arranged at intervals.

The burner throat 9 is arranged outermost in the burner.

When the system works, combustion-supporting air enters the combustor from the combustion-supporting air channel 2 and respectively enters the central air channel 21, the outer ring cyclone air channel 221 and the outer ring direct-current air channel 222, and the combustion-supporting air is divided into central air, outer ring cyclone air and outer ring direct-current air; fuel enters the burner from the central fuel passage 3 and the outer gas passage 83, respectively, wherein the central fuel entering from the central fuel passage 3 is passed to the central gas burner 42 and the internal gas lance 5, respectively. The central wind is ignited by the ignition gun to carry out the rich combustion in a swirling wind mode through the flame stabilizing disc 11 and the central gas which is obliquely sprayed inwards and directly sprayed from the central gas nozzle 42, so as to form central flame, inhibit the generation of fuel type NOx and thermal type NOx and reduce the emission of NOx. The flame stabilizing plate 12 protects the stability of the central flame, prevents a large amount of upstream air flow from impacting the central flame, and simultaneously, a small amount of air flows out of the cooling air holes, so that the cooling flame stabilizing plate 12 is not burnt out. A large amount of outward and forward external gas ejected from an external gas gun is mixed with direct current air at different angles and is subjected to light combustion, so that the generation of fuel type NOx and thermal type NOx is inhibited, and the emission of NOx is reduced. The axial flow wind with high intensity is gradually diffused to the periphery of the combustor, so that the outer fuel and the central fuel which are not fully combusted are fully and completely combusted. The gas is sprayed out from the built-in gas spray gun to connect the inner flame and the outer flame, so that the flame of the burner is further stabilized, and the burner has excellent stable flame performance.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various 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 (9)

1. The utility model provides a low calorific value low NOx gas burner of little choke, includes from center tuber pipe (211), central fuel pipe (31), outer gas spray gun (8) and combustor choke (9) of inside to outside coaxial setting, its characterized in that: the central air pipe (211) is internally provided with a central air channel (21), one end of the central air pipe (211) is provided with a central air pipe end face (212), the central air pipe end face (212) is provided with a flame stabilizing device (1), a central fuel channel (3) is internally arranged in the central fuel pipe (31), one end of the central fuel pipe (31) is provided with a central fuel pipe end face (32), the central fuel pipe end face (32) is provided with a central gas nozzle assembly (4), an outer ring swirl air channel (221) is formed between the central fuel pipe (31) and an outer gas spray gun (8), an outer ring direct-current air channel (222) is formed between a burner throat (9) and the outer gas spray gun (8), the central fuel pipe (31) is fixedly connected with a built-in gas spray gun (5), the built-in gas spray gun (5) is positioned in the outer ring swirl air channel (221), and the outer gas spray gun (81) is installed on the end face of the outer gas spray gun (8).

2. A small throat low heating value, low NOx gas burner as claimed in claim 1, wherein: the flame stabilizing device (1) comprises a flame stabilizing disc (11) and a flame stabilizing plate (12), the flame stabilizing disc (11) is fixed on the end face of the central air pipe (211), the inner flame stabilizing disc inner cylinder (111) is fixedly connected to the inner part of the flame stabilizing disc (11), the outer wall of the inner flame stabilizing disc inner cylinder (111) is fixedly connected with small swirl blades (112), the flame stabilizing plate (12) is fixed on the end face of the outer ring swirl air channel (221), and the end face of the flame stabilizing plate (12) is provided with a plurality of cooling air holes (121).

3. A small throat low heating value, low NOx gas burner as claimed in claim 1, wherein: the central gas nozzle assembly (4) comprises an inner gas distribution plate (41), the inner gas distribution plate (41) is fixed on the end face (32) of the central fuel pipe, and a plurality of central gas nozzles (42) are circumferentially arranged on the end face of the inner gas distribution plate (41).

4. A small throat low heating value, low NOx gas burner as claimed in claim 3, wherein: the central gas nozzle (42) is in one of a trapezoid shape or a circular shape, and the central gas nozzle (42) is annularly and multiply arranged on the inner gas distribution plate (41).

5. A small throat low heating value, low NOx gas burner as claimed in claim 3, wherein: the inner gas distribution plate (41) is of a horn-shaped structure which is reduced towards the inside of the central fuel channel (3), and the angle between the inner wall of the inner gas distribution plate (41) and the axis of the central fuel channel (3) is 0-60 degrees.

6. A small throat low heating value, low NOx gas burner as claimed in claim 1, wherein: the built-in gas spray gun (5) comprises an inner gas channel pipe (51) communicated with the central fuel pipe (31), and the other end of the inner gas channel pipe (51) is fixedly connected with an inner gas spray head (52).

7. A small throat low heating value, low NOx gas burner as claimed in claim 6, wherein: the inner gas jets (52) are oriented in a tangential direction to a circumference formed by the plurality of inner gas jets (52).

8. A small throat low heating value, low NOx gas burner as claimed in claim 6, wherein: outer gas shower nozzle (81) include a plurality of outer gas spouts one (811) and a plurality of outer gas spouts two (812), the spout of outer gas spout one (811) is regional towards outer lane direct current wind passageway (222), the spout orientation of outer gas spout two (812) is provided with two, a spout is regional towards outer lane direct current wind passageway (222), and be provided with the axis direction towards direct current wind passageway (22) towards gas spout (8121), outer gas spray gun (8) outside is provided with outer gas gun passageway (82) and surrounds including outer gas spray gun (8).

9. A small throat low calorific value low NOx gas burner as claimed in claim 6, wherein: a central cylinder (6) is arranged in the outer ring swirling air channel (221), a central cylinder end face (61) is arranged at one end of the central cylinder (6), and a plurality of swirling vanes (7) are fixedly connected between the central cylinder end face (61) and the inner wall of the central fuel pipe (31).

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