CN215675175U

CN215675175U - Ultra-low NOx gas burner combining flue gas internal circulation and semi-premixing

Info

Publication number: CN215675175U
Application number: CN202121972718.9U
Authority: CN
Inventors: 马子安; 刘冰
Original assignee: Shanghai Bonasen Environmental Technology Co ltd
Current assignee: Shanghai Bonasen Environmental Technology Co ltd
Priority date: 2021-08-22
Filing date: 2021-08-22
Publication date: 2022-01-28
Anticipated expiration: 2031-08-22

Abstract

The utility model provides an ultra-low NOx gas burner combining flue gas internal circulation and semi-premixing, which comprises: an outer throat of the burner; the graded air adjusting device is positioned in the outer throat of the combustor; one end of the central cylinder is inserted into the grading air adjusting device, and the other end of the central cylinder extends to the grading air adjusting device and the outer part of the outer throat of the combustor; the flame stabilizing device is positioned at one end of the central cylinder extending to the outside of the staged air adjusting device and the outer throat of the combustor; one end of the central gas gun is inserted into the central cylinder, and the other end of the central gas gun penetrates through the flame stabilizing device and extends to the outer side of the flame stabilizing device; a plurality of internal combustion air gun assemblies located between the staged air adjustment device and the central barrel; and the outer gas gun components are positioned between the grading air adjusting device and the outer throat of the combustor. This reality is novel can increase the gas proportion of gas and flue gas, air mixture before the burning, increases the negative pressure ability of combustor aircraft nose, reduces the resistance that high temperature flue gas returned, makes more flue gas flow back to combustor body department.

Description

Ultra-low NOx gas burner combining flue gas internal circulation and semi-premixing

Technical Field

The utility model relates to the technical field of combustion of industrial gas burners, in particular to an ultralow NOx gas burner with combination of flue gas internal circulation and semi-premixing.

Background

The NOx (nitrogen oxide) of a natural gas furnace is less than or equal to 30mg/Nm implemented from Beijing in 2015³Therefore, the technical route of 'low-nitrogen combustor + flue gas external circulation' in the low-nitrogen modification of the natural gas furnace is widely applied, the low-nitrogen combustor for the flue gas external circulation is fully developed, and the technical route of 'low-nitrogen combustor + flue gas external circulation' is adopted without bottleneck and difficulty.

The adoption of the flue gas external circulation technology can reduce the emission of NOx, but still has the defects of condensed water, boiler efficiency reduction, smoke circulation equipment increase and the like. In recent two years, a plurality of combustor manufacturers are continuously exploring and testing, smoke external circulation is not needed, only through innovation of combustor nose structures, more high-temperature smoke is circulated to the vicinity of the combustor nose in the furnace, oxygen quantity of fuel combustion is reduced, NOx emission is reduced, and the content of NOx is less than or equal to 30mg/Nm³Low nitrogen emissions. Some manufacturers apply for 30mg/Nm of smoke internal circulation³The patent protection of machine, mostly adopt in the patent of application protection to set up the flue gas inner loop solitary passageway and outer lane gas rifle head outside and set up flue gas air gas and mix the rifle in advance, and this structure is found through actual test operation, and the flue gas that the inner loop was returned enters into the flue gas inner loop passageway is less, and the combustor is when full load, still is difficult to stably reach 30mg Nm³Low nitrogen emissions. The head structure of the burner is continuously innovated, the capability of the internal circulation of the flue gas of the head of the burner is enhanced, and the burner with the internal circulation of the flue gas can stably burn and stably discharge NOx which is less than or equal to 30mg/Nm within 30 to 100 percent of the load of the boiler³Still has practical innovative significance.

SUMMERY OF THE UTILITY MODEL

In order to solve the defects of the prior art, the utility model provides an ultra-low NOx gas burner combining flue gas internal circulation and semi-premixing, which is used for solving the problems in the prior art.

The utility model provides an ultra-low NOx gas burner combining flue gas internal circulation and semi-premixing, which comprises:

an outer throat of the burner;

the staged air adjusting device is positioned in the outer throat of the combustor, has a distance with the outer throat of the combustor and is parallel to the outer throat of the combustor;

one end of the central cylinder is inserted into the grading air adjusting device, and the other end of the central cylinder extends to the grading air adjusting device and the outer part of the outer throat of the burner;

the flame stabilizing device is positioned at one end of the central cylinder, which extends to the outside of the staged air adjusting device and the outer throat of the combustor;

one end of the central gas gun is inserted into the central cylinder, and the other end of the central gas gun penetrates through the flame stabilizing device and extends to the outer side of the flame stabilizing device; an inner gas channel is arranged in the central gas gun;

a plurality of internal combustion gas gun assemblies located between the staged air adjustment device and the central barrel and spaced circumferentially of the central gas gun; one end of each inner gas gun assembly is communicated with the inner gas channel, and the other end of each inner gas gun assembly extends to the outer side of the flame stabilizing device;

the outer gas gun assemblies are positioned between the staged air adjusting device and the outer throat of the combustor and are distributed at intervals along the circumferential direction of the staged air adjusting device; one end of each outer gas gun assembly is inserted into the outer throat of the burner, and the other end of each outer gas gun assembly extends to the outside of the outer throat of the burner.

Optionally, a flame stabilizing plate is positioned at one end of the central cylinder extending to the outside of the staged air conditioning device and the burner outer throat; the flame stabilizing plate is provided with a plurality of first cyclone blades and a plurality of cooling air through holes, and the first cyclone blades are positioned on the periphery of the central gas gun and are distributed at intervals along the circumferential direction of the central cylinder.

Optionally, the combustor further comprises a plurality of second swirl vanes, which are located on the outer wall of the central cylinder extending to the staged air conditioning device and the outer end of the outer throat of the combustor and are arranged at intervals along the circumferential direction of the central cylinder.

Optionally, a gun head throat is formed in one end, extending to the outer side of the flame stabilizing device, of the central gas gun, the gun head throat is provided with a plurality of inclined gas nozzles, and the side wall, extending to the outer side of the flame stabilizing device, of one end, extending to the outer side of the flame stabilizing device, of the central gas gun is provided with a plurality of radial gas nozzles.

Optionally, the internal combustion air gun assembly comprises:

one end of the internal combustion air gun is communicated with the internal combustion air channel;

the inner flue gas air gas premixing gun is coaxially arranged with the inner gas gun, one end of the inner gas gun is sleeved at one end, far away from the inner gas channel, of the inner gas gun, and the other end of the inner gas gun extends to the outer side of the flame stabilizing device; and a first axial mixed gas nozzle and a first inclined spraying mixed gas nozzle are arranged at one end of the inner flue gas, air and gas premixing gun extending to the outer side of the flame stabilizing device.

Optionally, the outer gas gun assembly comprises:

one end of the outer gas gun is inserted between the outer throat of the burner and the grading air adjusting device and extends to the outside of the outer throat of the burner;

the outer flue gas air and gas premixing gun is coaxially arranged with the outer gas gun, and one end of the outer flue gas air and gas premixing gun is sleeved at one end of the outer gas gun, which extends to the outside of the gas outer throat; the outer flue gas air gas mixes rifle cover in outer gas rifle extends to the lateral wall of the outside one end of the outer larynx mouth of gas is equipped with air flue gas inlet, outer flue gas air gas mixes rifle in advance and keeps away from the one end of outer gas rifle is equipped with second axial gas mixture spout and second oblique jet gas mixture spout.

Optionally, one end of the burner outer throat close to the flame stabilizing device is provided with a front throat of the burner outer throat, and one end of the staged air adjusting device close to the front throat of the burner outer throat is provided with a front throat of the adjusting device.

Optionally, the side wall of the front throat of the combustion outer throat and the side wall of the front throat of the adjusting device are both obliquely crossed with the central line of the combustor outer throat, and the included angle between the side wall of the front throat of the combustion outer throat and the side wall of the front throat of the adjusting device and the central line of the combustor outer throat is 20-80 °.

As mentioned above, the ultra-low NOx gas burner combining the internal flue gas circulation and the semi-premixing has the following beneficial effects: this real neotype flue gas inner loop and half ultra-low NOx gas burner that combines together in advance increase the gas proportion of gas and flue gas, air mixing before the burning, other gas guns all adopt to set up flue gas air gas and mix the rifle in advance except that central gas gun, increase the negative pressure ability of combustor aircraft nose, reduce the resistance that high temperature flue gas returned, make more flue gas flow back to combustor body department. Through test of a test furnace, the low-nitrogen burner does not use smoke external circulation and can be stabilized within NOx of less than or equal to 30mg/Nm in different loads³And (4) discharging.

Drawings

FIG. 1 is a left side view of an ultra-low NOx gas burner of the present invention combining internal flue gas recirculation and semi-premixing;

FIG. 2 is a cross-sectional view of an ultra-low NOx gas burner of the present invention combining internal flue gas recirculation and semi-premixing;

FIG. 3 is a schematic illustration of an internal gas gun assembly and gas semi-premixing in a combined flue gas internal circulation and semi-premixing ultra-low NOx gas burner of the present invention;

FIGS. 4 a-4 b are schematic diagrams of the relative positions of the staged air conditioners in an ultra low NOx gas burner with combined internal flue gas recirculation and semi-premixing in accordance with the present invention;

FIG. 5 is a schematic illustration of the outer gas gun assembly and gas semi-premixing in the ultra-low NOx gas burner of the present invention combining internal flue gas recirculation and semi-premixing;

FIG. 6 is a schematic diagram of the combined flue gas recirculation and semi-premixing ultra-low NOx gas burner of the present invention during operation.

Element number description:

1. an inner combustion gas passage; 11. a central gas gun; 111. an oblique gas nozzle; 112. a radial gas nozzle; 12. an internal combustion air gun assembly; 121. an internal combustion air gun; 122. an inner flue gas air gas premixing gun; 1221. a first axial mixture jet; 1222. a first inclined jet mixing nozzle; 2. an external gas gun assembly; 21. an external gas gun; 22. an outer flue gas air gas premixing gun; 221. a second inclined jet mixing nozzle; 222. a second axial mixture nozzle; 223. an air flue gas inlet; 3. a central barrel; 4. a flame stabilizing device; 41. a flame stabilizing plate; 42. a first swirl vane; 43. cooling the vent holes; 5. a second swirl vane; 6. a staged air adjusting device 61, a front necking of the adjusting device; 7. an outer throat of the burner; 71. a front throat of the outer throat of the burner; 72. burning the end face of the outer throat; 8. an outer gas channel; 9. an air passage.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The preferred embodiments in the following description are given by way of example only, and other obvious variations will occur to those skilled in the art. The basic principles of the utility model, as defined in the following description, may be applied to other embodiments, variations, modifications, equivalents, and other technical solutions without departing from the spirit and scope of the utility model.

It will be understood by those skilled in the art that in the present disclosure, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for ease of description and simplicity of description, and do not indicate or imply that the referenced devices or components must be constructed and operated in a particular orientation and thus are not to be considered limiting.

Referring to fig. 1 and fig. 2, the present embodiment provides an ultra-low NOx gas burner with combined flue gas internal circulation and semi-premixing, comprising: a burner outer throat 7; the graded air adjusting device 6 is positioned in the burner outer throat 7, has a distance with the burner outer throat 7 and is parallel to the burner outer throat 7; one end of the central cylinder 3 is inserted into the grading air adjusting device 6, and the other end of the central cylinder extends to the outside of the grading air adjusting device 6 and the burner outer throat 7; the flame stabilizing device 4 is positioned at one end of the central cylinder 3 extending to the outside of the staged air adjusting device 6 and the burner outer throat 7; one end of the central gas gun 11 is inserted into the central barrel 3, and the other end of the central gas gun passes through the flame stabilizing device 4 and extends to the outer side of the flame stabilizing device 4; an inner gas channel 1 is arranged in the central gas gun 11; a plurality of internal combustion gas gun assemblies 12, which are located between the staged air adjustment device 6 and the central barrel 3 and are arranged at intervals in the circumferential direction of the central gas gun 11; one end of each inner gas gun assembly 12 is communicated with the inner gas channel 1, and the other end extends to the outer side of the flame stabilizing device 4; the outer gas gun assemblies 2 are positioned between the staged air adjusting device 6 and the burner outer throat 7 and are arranged at intervals along the circumferential direction of the staged air adjusting device 6; one end of each outer gas gun assembly 2 is inserted into the burner outer throat 7, and the other end of each outer gas gun assembly extends to the outside of the burner outer throat 7.

Specifically, the central cylinder 3 may be, but is not limited to, cylindrical.

The utility model improves the structure of the original flue gas internal circulation combustor through the innovation of the structural design of the combustor body, increases the internal premixing proportion of the fuel gas, greatly enhances the high-temperature flue gas absorption capacity of the combustor, enables most of the fuel gas to be subjected to semi-premixed combustion, and achieves that NOx is less than or equal to 30 mg/Nm/different load ranges when high-heat-value gas of fuel-free nitrogen-containing compounds for combustion is combusted through the internal circulation and the semi-premixing of the flue gas³And (4) discharging. And the special design of the central gun and the matching design of the central gun and the flame stabilizing device ensure that the burner has excellent combustion stabilizing capability. Through test table tests, the burner has the performance of safety, stability and reaching the emission of NOx of less than or equal to 30mg/Nm3 when high-heat-value gas without fuel nitrogen-containing compounds for smoke external circulation combustion is not used, and has strong competitiveness and wide market prospect in the market.

As an example, a flame stabilizing plate 41 is positioned at one end of the central cylinder 3 extending to the outside of the staged air conditioning device 6 and the burner outer throat 7; the flame stabilizing plate 41 is provided with a plurality of first swirl vanes 42 and a plurality of cooling air through holes 43, and the plurality of first swirl vanes 42 are located on the periphery of the central gas gun 11 and are arranged at intervals along the circumferential direction of the central cylinder 3.

Specifically, the flame stabilizing plate 41 may include, but is not limited to, a disk-shaped flame stabilizing plate 41.

Specifically, the first swirl vanes 42 are placed around the flame stabilizing plate 41 in a circle, and a plurality of first swirl vanes 42 are arranged as required, and fig. 1 takes 6 first swirl vanes 42 as an example; the cooling air through holes 43 are provided in plurality as required and are provided on the flame stabilizing plate 41. The low-speed low-pressure area is formed at the downstream area of the flame stabilizing device 4, so that the central flame is protected from being impacted by a large amount of upstream air flow, high-temperature flue gas can flow back to the vicinity of the flame stabilizing device 4, and the central flame is stabilized by providing ignition heat for the central gas gun 11. Meanwhile, high-temperature flue gas in the central area diffuses outwards to stabilize peripheral flame.

As an example, the ultra-low NOx gas burner with the combination of the flue gas internal circulation and the semi-premixing further includes a plurality of second swirl vanes 5, and the second swirl vanes 5 are located on the outer wall of the central cylinder 3 extending to the outer end of the staged air adjusting device 6 and the outer throat 7 of the burner, and are arranged at intervals along the circumferential direction of the central cylinder 3.

Specifically, the second swirl vanes 5 may be welded to the outer side of the front end of the central cylinder 3, and a plurality of pieces may be arranged as required, the second swirl vanes 5 may be arc-shaped, and fig. 1 exemplifies that 6 second swirl vanes 5 are arranged, and 2 second swirl vanes are in one group; however, in other embodiments, the number of the second swirl vanes 5 is not limited thereto.

As an example, one end of the central gas gun 11, which extends through the flame holding device 4 to the outside of the flame holding device 4, is provided with a gun head throat, the gun head throat is provided with a plurality of inclined gas nozzles 111, and one end of the central gas gun 11, which extends through the flame holding device 4 to the outside of the flame holding device 4, is provided with a plurality of radial gas nozzles 112.

Specifically, the central gas gun 11 extends out of the combustion outer throat end surface 72 and is arranged with the flame stabilizing device 4; the central gas gun 11 communicates with the internal gas passage 1.

By way of example, as shown in FIG. 3, the internal combustion air gun assembly 12 includes: an internal gas gun 121, one end of the internal gas gun 121 communicating with the internal gas passage 1; the inner flue gas air and gas premixing gun 122 is coaxially arranged with the inner gas gun 121, one end of the inner gas gun 122 is sleeved at one end of the inner gas gun 11 far away from the inner gas channel 1, and the other end of the inner gas gun 122 extends to the outer side of the flame stabilizing device 4; one end of the inner flue gas, air and gas premixing gun 122 extending to the outside of the flame stabilizing device 4 is provided with a first axial mixed gas nozzle 1221 and a first inclined spraying mixed gas nozzle 1222.

Specifically, the inner gas gun 121 guides the gas from the inner gas channel 1, and the diameter of the inner flue gas-air gas premixing gun 122 is larger than that of the inner gas gun 121.

Further, the internal combustion air gun assembly 12 may be arranged in multiple layers as required, and in the embodiment, 3 internal combustion air gun assemblies 1 are arranged as an example. As shown in fig. 2, the gas ejected from the internal gas gun 121 enters the internal flue gas-air gas premixing gun 122, and simultaneously, a small amount of combustion air and high-temperature flue gas also enter the internal flue gas-air gas premixing gun 122, and after the gas, air and flue gas form a gas-air mixture in the internal flue gas-air gas premixing gun 122, the gas, air and flue gas are respectively ejected from the first axial mixture nozzle 1221 and the first inclined jet mixing nozzle 1222 and enter the furnace. The air flue gas inlet 223 may also be disposed at the rear end of the inner flue gas air/gas premixing gun 122 as desired.

As an example, as shown in fig. 5, the external gas gun assembly 2 includes: one end of the outer gas gun 21 is inserted between the burner outer throat 7 and the grading wind adjusting device 6 and extends to the outside of the burner outer throat 7; the outer flue gas air gas premixing gun 22 is coaxially arranged with the outer gas gun 21, and one end of the outer flue gas air gas premixing gun is sleeved at one end of the outer gas gun 21 extending to the outside of the gas outer throat 7; the outer flue gas air gas mixes rifle 22 cover in the outer gas rifle 21 extends to the lateral wall of the outside one end of the outer larynx 7 of gas is equipped with air flue gas import 223, outer flue gas air mixes the rifle 22 and keeps away from the one end of outer gas rifle 21 is equipped with second axial gas mixture spout 222 and second mixed gas spout 221 of spouting to one side.

Specifically, the diameter of outer flue gas air gas mixes rifle 22 in advance is greater than the diameter of outer gas rifle 21, the front end of outer flue gas air gas mixes rifle 22 in advance is provided with second axial gas mixture spout 222 and second mixed spout 221 that spouts to one side, the upper reaches of outer flue gas air gas mixes rifle in advance is put air flue gas inlet 223, outer gas rifle 21 stretches into outer flue gas air gas mixes rifle 22 certain distance and arranges.

Further, the outer gas gun assemblies 2 are arranged in multiple layers according to needs, and in the embodiment, 6 outer gas gun assemblies 2 are arranged as an example. As shown in fig. 6, the gas ejected from the outer gas gun 21 enters the outer flue gas air gas premixing gun 22, and simultaneously, a small amount of combustion air and high temperature flue gas respectively enter the outer flue gas air gas premixing gun 22 from the upper port of the outer flue gas air gas premixing gun 22 and the air flue gas inlet 223, and after the gas, air and flue gas form a gas-air-flue gas mixture in the outer flue gas air gas premixing gun 22, the gas, air and flue gas are respectively ejected from the second axial mixed gas nozzle 222 and the second inclined jet mixed nozzle 221 and enter the furnace.

As an example, one end of the burner outer throat 7 adjacent to the flame holder 4 is provided with a front throat 71 of the burner outer throat, and one end of the staged air regulator 6 adjacent to the front throat of the burner outer throat 7 is provided with a front throat 61 of the regulator.

As an example, as shown in fig. 4a and 4b, the side wall of the front throat 71 of the combustion outer throat and the side wall of the front throat 61 of the adjusting device are both oblique to the center line of the combustor outer throat 7, and the included angle between the side wall of the front throat 71 of the combustion outer throat and the side wall of the front throat 61 of the adjusting device and the center line of the combustor outer throat 7 is 20 ° to 80 °.

Specifically, the included angles between the side wall of the front throat 71 of the combustion outer throat and the side wall of the front throat 61 of the adjusting device and the central line can be 20 degrees, 40 degrees, 60 degrees or 80 degrees, and the like.

Specifically, the staged air adjusting device 6 is cylindrical with a throat at the front end, as shown in fig. 4a to 4b, the front throat 61 of the adjusting device extends out of the front throat 71 of the burner, and the air ratio respectively flowing out of the central cylinder 3 and the air flow rate outside the central cylinder 3 are adjusted by the back and forth movement of the staged air adjusting device 6.

Specifically, the other gas guns except the central gas gun 11 are provided with a flue gas-air gas premixing gun, so that the combustion temperature and oxygen content of fuel are reduced, and further the emission of NOx is reduced; the gas guns extend out of the end face 72 of the outer throat of the combustion, the spaces outside the outer throat 7 of the combustor with the necking are all channels for internal circulation of the flue gas, the recycled flue gas is basically free of blocking, the pressure overcome by the recycled flue gas is minimum, the flue gas can be recycled to the maximum extent, the oxygen quantity of fuel combustion is reduced, and further the emission of NOx is reduced.

When the ultra-low NOx gas burner combining the flue gas internal circulation and the semi-premixing works, combustion-supporting air enters the burner from the air channel 9, and fuel enters the burner from the outer gas channel 8 and the inner gas channel 1 respectively. Combustion-supporting air enters the air channel 9, flows forwards and respectively enters the inside and the outside of the staged air adjusting device 6, the combustion-supporting air respectively passes through the front necking 61 of the staged air adjusting device and the front necking 71 of the outer throat of the burner, the air flow rate is greatly accelerated and is ejected out of the staged air adjusting device 6 and the outer throat 71 of the burner at a high speed to form increased negative pressure, peripheral high-temperature flue gas is sucked and rolled to flow back to the outer throat of the burner, and the high-temperature flue gas with low oxygen content is mixed with the combustion-supporting air to form flue gas-air mixed gas with low oxygen content. The combustion-supporting air entering the graded air adjusting device 6 flows out of the flame stabilizing device 4 in the central cylinder 3 and the space outside the central cylinder 3 through the shunting of the central cylinder 3 and enters the hearth. When the combustion-supporting air entering the central cylinder 3 flows through the flame stabilizing plate 41, most of the air flows out of the first swirl vanes 42 to form swirl air, and a small part of the air flows out of the cooling air holes 43 to cool the flame stabilizing plate 41. And combustion-supporting air entering the grading air adjusting device 6 outside the central cylinder 3 is mixed with high-temperature flue gas returned by internal circulation to form low-oxygen combustion-supporting air, and part of the combustion-supporting air forms cyclone air by the second cyclone blades 5.

The gas that gets into from interior gas channel 1 gets into in the combustor gets into in the center gas rifle 11, the gas that gets into center gas rifle 11 is followed respectively in slant gas spout 111 with radial gas spout 112, from different positions in different directions with different angles spout in the furnace, mixes with different positions and combustion-supporting wind, and the high temperature heat source ignition of burning torch carries out low nitrogen combustion, forms central flame, flame stabilizing device 4 has blockked the impact of upstream air current to central flame to make partial flue gas backward flow to flame stabilizing device 4 department makes this combustor have excellent steady burning ability. Other gas entering the combustor from the internal gas channel 1 enters different internal gas gun assemblies 12 respectively, gas ejected from the internal gas gun 121 enters the internal flue gas-air gas premixing gun 122, meanwhile, a small amount of combustion air and high-temperature flue gas also enter the internal flue gas-air gas premixing gun 122, after gas, air and flue gas form gas-air mixed gas in the internal flue gas-air gas premixing gun 122, the gas, air and flue gas are ejected into a hearth from the first axial mixed gas nozzle 1221 and the first inclined jet mixing nozzle 1222 respectively, and the low-oxygen flue gas-air mixed gas is subjected to low-oxygen concentrated combustion and semi-premixed combustion, so that the generated NOx amount is extremely small. Follow spun gas gets into in outer gas gun 21 outer flue gas air gas mixes rifle 22 in advance, and simultaneously a small amount of combustion air and high temperature flue gas are followed respectively outer flue gas air gas mixes the last port of rifle 22 in advance with air flue gas inlet 223 gets into outer flue gas air gas mixes rifle 22 in advance, gas, air, flue gas are in after forming gas air flue gas mixture in outer flue gas air gas mixes rifle 22, follow respectively second axial gas mixture spout 222 with spout the blowout gets into furnace in the second mixes spout 221 to one side, and the flue gas air gas mixture that meets low oxygen volume carries out light burning and the semi-premix burning of low oxygen volume, and the NOx volume of formation is minimum.

The ultra-low NOx gas burner combining the flue gas internal circulation and the semi-premixing improves the structure of the burner on the current market, enhances the negative pressure capability of the burner for absorbing the internal circulation flue gas, reduces the resistance of the flue gas recirculation reflux, increases the proportion of the semi-premixing gas, and tests prove that the ultra-low NOx gas burner can reach NOx less than or equal to 30mg/Nm within different load ranges when high-heat-value gas without fuel nitrogen-containing compounds is combusted under the condition of not using the flue gas external circulation³The combustion is safe and stable.

The ultra-low NOx gas burner combining the internal circulation of the flue gas and the semi-premixing has the following beneficial effects:

1. the downstream of the air ejection outer throat is not provided with an outer throat, and a separate flue gas inner circulation channel is not created for the recirculated flue gas any more, so that the space outside the throat of the burner outer throat 7 can be called as a flue gas inner circulation channel, the resistance of the flue gas inner circulation is reduced, the capability of the combustor inner circulation can be enhanced, the recirculated flue gas returning to the area of the burner outer throat 7 is increased, and the emission of NOx is reduced.

2. Most of the gas nozzles are arranged at the downstream of the front throat of the outer throat 7 of the combustor, so that the gas quantity sprayed out of the outer throat 7 of the combustor is greatly reduced, and the gas at the downstream of the front throat of the outer throat 7 of the combustor is sprayed out at a high speed.

3. The premixing proportion in the fuel gas is greatly increased. Except the gas of the central gas gun 11, the peripheries of other gas guns are all provided with coaxial flue gas air and gas premixing guns, so that after the gas is sprayed out of the gas guns, the gas is firstly mixed with part of combustion air and flue gas to form flue gas air and gas mixed gas, and then the gas is combusted after meeting the high-temperature flue gas. The flue gas air gas mixture is semi-premixed gas, and a temperature field generated after the mixed gas is combusted is uniform without a local high-temperature area, so that the generation of thermal NOx can be reduced, and the emission of NOx is reduced. The gas ratio in the center gun is small, so that basically all the gas is subjected to semi-premixed combustion, and the emission of NOx can be greatly reduced.

4. The central gas gun 11 is combined with the flame stabilizing device 4 to enhance the combustion stabilizing capability of the burner. The gas in the central gas gun 11 is sprayed out from different positions, different angles and different directions, so that the central gas and the combustion air are fully mixed; the internal circulation flue gas flowing back to the downstream of the flame stabilizing device 4 continuously provides combustion ignition heat for the central fuel gas, and the flame stabilizing device blocks a large amount of upstream airflow impact, so that the central flame can be stabilized, and the burner has excellent combustion stabilizing capability.

It will be evident to those skilled in the art that the utility model is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the utility model being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. An ultra-low NOx gas burner combining flue gas internal circulation and semi-premixing, comprising:

an outer throat of the burner;

2. The combined flue gas internal circulation and semi-premixing ultra-low NOx gas burner of claim 1, wherein: the flame holding device comprises:

the flame stabilizing plate is positioned at one end of the central cylinder, which extends to the outside of the staged air adjusting device and the outer throat of the combustor; the flame stabilizing plate is provided with a plurality of first cyclone blades and a plurality of cooling air through holes, and the first cyclone blades are positioned on the periphery of the central gas gun and are distributed at intervals along the circumferential direction of the central cylinder.

3. The combined flue gas internal circulation and semi-premixing ultra-low NOx gas burner of claim 2, wherein: the second swirl blades are positioned on the outer wall of the central cylinder, extend to the graded air adjusting device and one end of the outer throat of the combustor, and are arranged at intervals along the circumferential direction of the central cylinder.

4. The combined flue gas internal circulation and semi-premixing ultra-low NOx gas burner of claim 1, wherein: the central gas gun penetrates through the flame stabilizing device and extends to one end of the outer side of the flame stabilizing device and is provided with a gun head reducing port, a plurality of inclined gas nozzles are arranged on the gun head reducing port, and the central gas gun penetrates through the flame stabilizing device and extends to one end side wall of the outer side of the flame stabilizing device and is provided with a plurality of radial gas nozzles.

5. The combined flue gas internal circulation and semi-premixing ultra-low NOx gas burner of claim 1, wherein: the internal combustion air gun assembly includes:

6. The combined flue gas internal circulation and semi-premixing ultra-low NOx gas burner of claim 1, wherein: the external gas gun assembly includes:

7. The combined flue gas internal circulation and semi-premixing ultra-low NOx gas burner of claim 1, wherein: the burner outer throat is close to one end of the flame stabilizing device and is provided with a front throat of the burning outer throat, and the grading wind adjusting device is close to one end of the front throat of the burner outer throat and is provided with a front throat of the adjusting device.

8. The combined flue gas internal circulation and semi-premixing ultra-low NOx gas burner of claim 7, wherein: the side wall of the front throat of the combustion outer throat and the side wall of the front throat of the adjusting device are obliquely crossed with the central line of the combustor outer throat, and the included angles between the side wall of the front throat of the combustion outer throat and the side wall of the front throat of the adjusting device and the central line of the combustor outer throat are 20-80 degrees.