CN111121005B

CN111121005B - Decoupling gas burner and using method thereof

Info

Publication number: CN111121005B
Application number: CN201911212741.5A
Authority: CN
Inventors: 郝江平; 高士秋; 余剑; 李长明; 刘周恩; 赵康
Original assignee: Institute of Process Engineering of CAS
Current assignee: Institute of Process Engineering of CAS
Priority date: 2019-12-02
Filing date: 2019-12-02
Publication date: 2021-04-09
Anticipated expiration: 2039-12-02
Also published as: CN111121005A

Abstract

The invention provides a solutionThe decoupling gas burner sequentially comprises a central gas pipe, a primary air cylinder, a secondary air cylinder and an outer cylinder which are coaxially arranged from inside to outside; an annular air chamber is formed between the outer cylinder and the primary air cylinder, and an air chamber end plate is arranged at one end of the air chamber close to the hearth; one end of the central gas pipe close to the hearth is provided with a frustum-shaped central gas pipe end cover, and the peripheral surface of the central gas pipe end cover is provided with at least one central gas spray hole; an annular primary air channel is formed between the central gas pipe and the primary air cylinder, and a primary air swirl blade is arranged at one end of the primary air channel close to the hearth; a secondary air channel is formed between the primary air barrel and the secondary air barrel, a secondary air swirl blade is arranged at one end of the secondary air channel close to the hearth, and one end of the secondary air channel far away from the hearth is communicated with the air chamber. The invention adopts a novel staged combustion mode, and reduces the thermal NO under the condition of ensuring the combustion efficiency_xAnd (4) generating.

Description

Decoupling gas burner and using method thereof

Technical Field

The invention belongs to the technical field of combustion equipment, relates to a gas burner and a using method thereof, and particularly relates to a decoupling gas burner and a using method thereof.

Background

For fuel gas containing NO fuel nitrogen or fuel gas containing low fuel nitrogen, a method of increasing excess air coefficient can be adopted to reduce combustion temperature so as to control thermal NO_xAnd (4) generating. However, because the gas is relatively intensively injected into the air flow, when the gas is mixed with the air in the initial combustion stage, a transition region with the stoichiometric ratio of gas quantity to oxygen quantity close to each other appears, and the thermal NO is generated at local high temperature_xUltra-low emissions cannot be achieved. In addition, too much excess air also increases the heat loss of the exhaust smoke and the power consumption of the fan, and reduces the energy efficiency.

Mixing of air with externally circulated flue gas is also a common method for reducing the peak combustion temperature of the gas. But the proposal needs larger amount of recycled flue gas, the flow resistance of the boiler air duct and the flue is increased, and the power consumption of the fan is increased. If the circulating flue gas is sucked in a mode of throttling the inlet of the air feeder, the pressure head of the whole fan is increased under the full flow, and the power consumption loss of the fan is more obvious. The excessive external circulation flue gas volume also can make the furnace temperature wholly reduce, and radiant heat transfer volume reduces by a wide margin, and furnace outlet flue gas enthalpy increases, and the heat loss of discharging fume also increases. Increased flow resistance and flue gas loss also result in a reduction in the maximum boiler output.

The entrainment effect of the airflow at the outlet of the combustor promotes the circulation of the flue gas in the furnace, and the concentration of fuel and oxygen at the initial stage of combustion can be controlled, thereby being beneficial to reducing the peak value of the combustion temperature. However, for a large burner, the ratio of the peripheral length to the sectional area of the airflow is reduced, the flow rate ratio of the internal circulation flue gas is small, and NO is difficult to achieve_xUltra low emission effect.

Flue gas recirculation coupled with staged combustion is a major technology developed recently, which can reduce the amount of flue gas external circulation to some extent. But the staged combustion and the large amount of flue gas (low oxygen concentration) cause the mass transfer of combustible materials and oxygen to be poor, the combustible materials and the oxygen are not easy to burn out in the later combustion period, the combustion efficiency is reduced, and the coupling relation between the low-nitrogen combustion and the high-efficiency combustion is strengthened.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a decoupling gas burner and a using method thereof_xAnd (4) generating.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the invention provides a decoupling gas burner, which sequentially comprises a central gas pipe, a primary air cylinder, a secondary air cylinder and an outer cylinder from inside to outside, wherein the central gas pipe, the primary air cylinder, the secondary air cylinder and the outer cylinder are coaxially arranged.

An annular air chamber is formed between the outer cylinder and the primary air cylinder, and an air chamber end plate is arranged at one end of the air chamber close to the hearth.

One end of the central gas pipe close to the hearth is provided with a frustum-shaped central gas pipe end cover, and the peripheral surface of the central gas pipe end cover is provided with at least one central gas spray hole.

An annular primary air channel is formed between the central gas pipe and the primary air cylinder, and a primary air swirl blade is arranged at one end of the primary air channel close to the hearth.

An annular secondary air channel is formed between the primary air barrel and the secondary air barrel, a secondary air swirl blade is arranged at one end of the secondary air channel close to the hearth, one end of the secondary air channel far away from the hearth is communicated with the air chamber, and the air in the air chamber enters the secondary air channel and is sprayed into the hearth through the secondary air swirl blade.

The invention fully utilizes the internal circulation of the flue gas to control the peak value of the combustion temperature, the central fuel gas is firstly mixed and combusted with the primary air with the highest rotational flow intensity after entering the hearth, and the initial combustion temperature is lower due to quick mixing, lower air-fuel ratio of the primary air and the mixing of the circulating flue gas; after the primary combustion of the central gas, the central gas is continuously mixed and combusted along with the mixed flue gas and the secondary air, and the combustion temperature is lower because the total air volume of the primary air and the secondary air is larger than that of the central gas; the central gas is firstly subjected to oxygen-deficient combustion, then the amount of flue gas is increased, the consumption and diffusion of the gas and oxygen reduce the concentration peak value of the gas and oxygen, and when the central gas is mixed with excess air for oxygen-enriched combustion, local high-concentration oxygen and gas cannot occur. Obviously reduce the flow and the air pressure of the external circulation flue gas, and reduce the thermal NO under the condition of ensuring the overall efficiency_xAnd (4) generating.

As a preferable technical scheme of the invention, the installation inclination angle between the primary wind swirl vane and the axis of the outer cylinder is larger than the installation inclination angle between the secondary wind swirl vane and the axis of the outer cylinder.

In the invention, the end cover of the central gas pipe adopts a convex frustum-shaped structure with larger outer diameter, and the inclination angle of the air duct swirl vanes from the outer edge to the center is gradually increased, so that the space and the backflow entrainment capacity of central backflow flue gas are increased, the fuel and oxygen concentration at the initial stage of combustion is reduced, and the reduction and even the cancellation of central external circulation flue gas are facilitated. The enhancement of the high temperature central internal circulation is also beneficial for low load stable combustion at low oxygen.

Preferably, the distance between the end face of the primary air cylinder on the side close to the furnace chamber and the end face of the outer cylinder on the side close to the furnace chamber is greater than the distance between the end face of the secondary air cylinder on the side close to the furnace chamber and the end face of the outer cylinder on the side close to the furnace chamber.

In the invention, the installation inclination angle of the swirl vanes from the outer edge to the center and the distance from the swirl vanes to the hearth are sequentially increased, so that the cross mixing between the flue gas combusted at the initial stage and secondary air is strengthened, the cooling effect of excess air is also enhanced, and the local high-temperature phenomenon is avoided.

As a preferable technical scheme of the invention, at least one outer edge burner is arranged at the annular cavity between the outer cylinder and the secondary air cylinder along the circumferential direction.

Preferably, the outer edge combustor sequentially comprises an outer edge gas pipe, a gradually expanding short pipe and a tertiary air cylinder body from inside to outside, wherein the outer edge gas pipe, the gradually expanding short pipe and the tertiary air cylinder body are coaxially arranged.

Preferably, the divergent short pipe is in a thin-wall circular truncated cone structure, the diameter of the cross section of the divergent short pipe is gradually increased along the air inlet direction, and the divergent short pipe comprises a large-diameter end close to the hearth and a small-diameter end far away from the hearth.

In the invention, because the special structure of the divergent pipe causes the outward diffusion of the outside tertiary air, the mixing of air and the outer edge fuel gas can be delayed, the combustion stroke of the outer edge fuel gas is prolonged, and the control of the combustion intensity of the front section in the hearth and the control of the whole combustion temperature by utilizing the heat absorption process of the hearth are facilitated.

Preferably, a tertiary air channel is formed between the tertiary air cylinder and the outer edge gas pipe.

Preferably, one end of the tertiary air channel, which is far away from the hearth, is communicated with the air chamber.

Preferably, an outer tertiary air channel is formed between the tertiary air cylinder and the divergent short pipe, and a cavity formed by the inner wall of the divergent short pipe in an enclosing manner is an inner tertiary air channel.

Preferably, one end of the outer tertiary air channel, which is close to the hearth, is provided with an edge inner circulation cover plate, and the edge inner circulation cover plate blocks part of gas outlets of the outer tertiary air channel.

Preferably, the edge inner circulation cover plate blocks a gas outlet on one side of the outer tertiary air channel close to the outer cylinder.

In the invention, the outer edge burners are arranged at intervals, so that the entrainment perimeter of the inner airflow and the outer airflow of the whole burner is increased, and the ratio of the internal circulation volume of the flue gas is obviously improved; in addition, the outer edge combustor is provided with the edge inner circulation cover plate on the outer side to plug the outer edge of tertiary air, so that the inner entrainment periphery of the outer edge combustor can be increased, outer edge low-temperature flue gas enters the center from the plugging edge, and the entrainment backflow amount of the flue gas in the furnace to the outer edge combustor is increased.

The outer edge gas is only mixed with a small amount of inner tertiary air at the initial stage and then enters the furnace for combustion, and the air-fuel ratio of the mixed gas is small, so that the combustion temperature is low; in addition, due to the effect of the gradually expanding pipe, the outer tertiary air is diffused outwards, the mixing of air and outer edge gas can be delayed, the combustion stroke of the outer edge gas is prolonged, and the control of the combustion intensity of the front section in the hearth and the control of the overall combustion temperature by utilizing the heat absorption process of the hearth are facilitated.

As a preferred technical scheme of the present invention, the outer edge burner further includes an outer edge outer circulation flue gas pipe sleeved outside the outer edge gas pipe, and an outer edge outer circulation flue gas channel is formed between the outer edge outer circulation flue gas pipe and the outer edge gas pipe.

In the present invention, the combustion temperature can be further controlled by mixing external circulation flue gas into the air. In addition, the outer edge outer circulation flue gas is wrapped outside the outer edge fuel gas, so that the initial combustion temperature of the outer edge fuel gas can be further reduced and the combustion stroke of the outer edge fuel gas can be prolonged by the small outer circulation flue gas flow.

Preferably, one end of the outer edge outer circulation flue gas pipe is butted with the small-diameter end of the gradually-expanding short pipe.

Preferably, the outer diameter of the outer edge outer circulation flue gas pipe is smaller than or equal to the inner diameter of the small-diameter end of the tapered short pipe, and gas in the outer side tertiary air channel enters the inner side tertiary air channel through a gap at the joint of the outer edge outer circulation flue gas pipe and the tapered short pipe and then is sprayed into a hearth through the large-diameter end.

As a preferred technical scheme of the invention, the peripheral surface of the divergent short pipe is provided with at least one air inlet, and the gas in the outer tertiary air channel enters the inner tertiary air channel through the air inlet and then is sprayed into a hearth from the large-diameter end.

Preferably, the air inlet is arranged close to the small-diameter end.

As a preferable technical scheme of the invention, one end of the outer edge gas pipe, which is close to the hearth, is provided with an outer edge gas pipe cover plate.

Preferably, the outer edge gas pipe cover plate is provided with at least one outer edge gas spray hole.

As a preferable technical scheme of the invention, an annular secondary air segmentation barrel coaxial with the outer barrel is arranged in the secondary air channel.

Preferably, the secondary wind segmentation barrel divides the secondary wind channel into an outer secondary wind channel and an inner secondary wind channel which are communicated, an annular outer secondary wind channel is formed between the secondary wind segmentation barrel and the secondary wind barrel, and an annular inner secondary wind channel is formed between the secondary wind segmentation barrel and the primary wind barrel.

Preferably, one end of the outer secondary air channel, which is close to the hearth, is provided with outer secondary air swirl blades.

Preferably, one end of the inner secondary air channel, which is close to the hearth, is provided with inner secondary air swirl blades.

Preferably, the installation inclination angle between the primary wind swirl blades and the axis of the outer barrel is larger than that between the inner secondary wind swirl blades and the axis of the outer barrel, and the installation inclination angle between the inner secondary wind swirl blades and the axis of the outer barrel is larger than that between the outer secondary wind swirl blades and the axis of the outer barrel.

In the invention, the installation angle of the swirl blades is changed to gradually reduce the swirl strength of the flue gas from inside to outside, so that the mixing of the inside and the outside can be enhanced, meanwhile, the excessive air in the central combustion area can be prevented from being mixed with the outer edge gas earlier, and the extension of the outer edge gas combustion is ensured.

Preferably, the distance between the end face of the primary air cylinder on the side close to the furnace chamber and the end face of the outer cylinder on the side close to the furnace chamber is greater than the distance between the end face of the secondary air partition cylinder on the side close to the furnace chamber and the end face of the outer cylinder on the side close to the furnace chamber, and the distance between the end face of the secondary air partition cylinder on the side close to the furnace chamber and the end face of the outer cylinder on the side close to the furnace chamber is greater than the distance between the end face of the secondary air cylinder on the side close to the furnace chamber and the end.

In a second aspect, the present invention provides a method of using the decoupled gas burner according to the first aspect, said method comprising:

the central gas is sprayed into the hearth through the central gas pipe and then mixed with the primary air introduced from the primary air channel for primary combustion, and the central gas after combustion and the secondary air introduced from the secondary air channel are continuously mixed and combusted.

As a preferred technical solution of the present invention, the using method specifically comprises the following steps:

injecting central gas into a hearth through a central gas pipe, introducing primary air from a primary air channel into the hearth through a primary air swirl vane, and mixing the central gas and the primary air in the hearth for primary combustion;

(II) the gas in the air chamber enters a secondary air channel to form secondary air, the secondary air is divided into two streams, one stream enters an outer secondary air channel to form outer secondary air, the outer secondary air passes through an outer secondary air cyclone blade to enter a hearth, the other stream enters an inner secondary air channel to enter the hearth through an inner secondary air cyclone blade, and the primarily combusted central gas is mixed with the two streams of secondary air to be combusted in the hearth;

(III) the gas in the air chamber enters an outer tertiary air channel to form outer tertiary air, the outer tertiary air enters an inner tertiary air channel from the outer tertiary air channel through a gap at the joint of an outer edge outer circulation flue gas pipe and a tapered short pipe or an air inlet arranged on a tapered short pipe to form inner tertiary air, the outer edge outer circulation flue gas is introduced from the outer edge outer circulation flue gas pipe, the inner tertiary air, the outer edge outer circulation flue gas and outer edge fuel gas sprayed from the outer edge fuel gas pipe are mixed and combusted at low temperature, and then the outer edge fuel gas and the outer tertiary air are mixed and combusted.

The invention adopts a novel staged combustion mode, controls the temperature of the whole gas combustion process to be uniform by internal circulation of the flue gas or assistance of smaller external circulation of the flue gas, and reduces the thermal NO under the condition of ensuring the combustion efficiency_xAnd (4) generating. The central combustion zone first burns with low air-fuel ratio and mixed-cycle flue gas, which then mixes into secondary air with a large excess air factor. After primary combustion in the central combustion area, flue gas containing low-concentration fuel gas is mixed into excessive secondary air, so that a local oxygen-enriched and rich combustion area can be avoided. The outer edge combustor firstly burns with a small amount of circulating smoke, the inner tertiary air and the outer edge fuel gas at a low temperature, and then is mixed with the outer tertiary air and the excess air in the central combustion area to burn out. The outer edge fuel gas is wrapped by outer tertiary air deflected outwards and is mixed with central area flue gas with gradually reduced swirl strength from inside to outside, so that the combustion process of the outer edge fuel gas can be prolonged, the excessive combustion strength of the front section of the hearth is avoided, and the heat absorption of the hearth is utilized to control the overall combustion temperature. The inner and outer combustion areas of the invention improve entrainment capacity by expanding the airflow jet flow perimeter, enhance the internal circulation of the flue gas to control the peak value of combustion temperature and reduce the requirement on the external circulation of the flue gas. Because the outer edge gas is wrapped in the air, the outer edge gas can be completely mixed with the combustion air in a proper stroke and burnt out.

It should be noted that, in the present invention, the air entering the decoupling gas burner is divided into two parts which can control the flow rate by a valve and respectively and independently enter the decoupling gas burner, wherein the central air enters the primary air channel, and the air in the air chamber enters the air chamber.

In a preferred embodiment of the present invention, the central gas in step (i) accounts for 20% to 80% of the total gas amount of the decoupled gas burner, and may be, for example, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%, but is not limited to the values listed, and other values not listed in this range are also applicable.

Preferably, the primary air comprises central outer circulation flue gas and central air.

Preferably, the volume ratio of the central outer circulation flue gas volume to the total air volume of the decoupled gas burner is 0% to 10% in a standard state, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, but is not limited to the enumerated values, and other non-enumerated values in the range of the enumerated values are also applicable.

Preferably, the central air volume of the primary air is 5% to 30% of the total air volume of the decoupled gas burner, for example 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% or 30%, but is not limited to the values listed, and other values not listed within this range of values are equally applicable.

Preferably, the gas in the plenum in step (ii) comprises flue gas circulated outside the plenum and plenum air.

In the invention, the combustion temperature can be further controlled by mixing the external circulation flue gas into the air, the external circulation flue gas can be provided with circulation power by an independent fan, namely, the very large full-flow throttling loss caused by a blower throttling suction mode is avoided, different amounts of external circulation flue gas can be supplied to different areas according to the requirements, and the maximum effect is obtained by the minimum external circulation flue gas amount.

Preferably, the volume ratio of the amount of the flue gas circulating outside the air chamber to the total amount of the air of the decoupling gas burner under the standard state is 0% to 15%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%, but not limited to the enumerated values, and other non-enumerated values in the numerical range are also applicable.

Preferably, the second stage air plenum air volume is 20% to 70% of the total air volume, and may be, for example, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70%, but is not limited to the values recited, and other values not recited within this range are equally applicable.

Preferably, the amount of air in the outer secondary air is 20% to 50% of the total amount of air in the secondary air, and may be, for example, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, or 50%, but is not limited to the values listed, and other values not listed in this range of values are equally applicable.

Preferably, the total air quantity of the primary air and the secondary air is more than or equal to the theoretical air quantity required by the central gas.

Preferably, the ratio of the total air volume of the primary air and the secondary air to the theoretical air volume required for the central gas is 1-2, and may be, for example, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2.0, but not limited to the recited values, and other values not recited in the range of the values are also applicable.

Preferably, the third air stream from the inner side of step (iii) is 0% to 60% of the total third air stream, and may be, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55% or 60%, but is not limited to the values listed, and other values not listed in this range are also applicable.

Preferably, the inner tertiary air volume is smaller than the theoretical air volume required by the outer edge gas.

Preferably, the ratio of the inner tertiary air volume to the theoretical air volume required by the outer edge gas is 0-0.8, and may be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 or 0.8, for example. But not limited to, the recited values and other values not recited within the range of values are equally applicable.

Preferably, the volume ratio of the peripherally recycled flue gas to the total burner air is 0% to 10% in the standard state, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, but not limited to the values listed, and other values not listed in this range are also applicable.

The recitation of numerical ranges herein includes not only the above-recited numerical values, but also any numerical values between non-recited numerical ranges, and is not intended to be exhaustive or to limit the invention to the precise numerical values encompassed within the range for brevity and clarity.

The system refers to an equipment system, or a production equipment.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention makes full use of the internal circulation of the flue gas to control the peak value of the combustion temperature. The end cover of the central gas pipe adopts a convex mushroom head shape with larger outer diameter, and the inclination angle of the air duct blade is gradually increased from the outer edge to the center, so that the space and the backflow entrainment capacity of central backflow flue gas are increased, the fuel and oxygen concentration at the initial stage of combustion is reduced, and the reduction and even the cancellation of central outer circulation flue gas are facilitated. The enhancement of the high temperature central internal circulation is also beneficial for low load stable combustion at low oxygen. The outer edge burners are arranged at intervals, so that the entrainment perimeter of the inner airflow and the outer airflow of the whole burner is increased, and the ratio of the internal circulation amount of the flue gas is obviously improved; in addition, the outer edge combustor is provided with the edge inner circulation cover plate on the outer side to plug the outer edge of tertiary air, so that the inner entrainment periphery of the outer edge combustor can be increased, outer edge low-temperature flue gas enters the center from the plugging edge, and the entrainment backflow amount of the flue gas in the furnace to the outer edge combustor is increased.

(2) After entering a hearth, central fuel gas is firstly mixed and combusted with primary air with the highest rotational flow strength, and the initial combustion temperature is lower due to the rapid mixing, the low air-fuel ratio of the primary air and the mixing of circulating flue gas; after the primary combustion of the central gas, the central gas is continuously mixed and combusted along with the mixed flue gas and the secondary air, and the combustion temperature is lower because the total air volume of the primary air and the secondary air is larger than that of the central gas; the central gas is firstly subjected to oxygen-deficient combustion, the smoke gas amount is increased, the concentration peak value of the gas and oxygen is reduced due to consumption and diffusion of the gas and the oxygen, and when the gas and the oxygen are mixed with excess air for oxygen-enriched combustion, local high-concentration oxygen and gas cannot occur.

(3) The outer edge gas is only mixed with a small amount of inner tertiary air at the initial stage and then enters the furnace for combustion, and the air-fuel ratio of the mixed gas is small, so that the combustion temperature is low; in addition, due to the effect of the gradually expanding pipe, the outer tertiary air is diffused outwards, the mixing of air and outer edge gas can be delayed, the combustion stroke of the outer edge gas is prolonged, and the control of the combustion intensity of the front section in the hearth and the control of the overall combustion temperature by utilizing the heat absorption process of the hearth are facilitated.

(3) From inside to outside reduction of flue gas whirl intensity gradually, can strengthen the inboard mixture to the outside, can avoid the earlier outer fringe gas mixture of excess air in central combustion area simultaneously, the extension of guarantee outer fringe gas combustion. In addition, because the outer edge gas is wrapped by a certain amount of air and the excess air in the central combustion area adopts a rotational flow form, the outer edge gas can be completely mixed with the internal and external combustion air in a proper stroke, and the combustible can be completely combusted.

(4) The combustion temperature can be further controlled by mixing external circulation flue gas in the air. In addition, the outer edge outer circulation flue gas is wrapped outside the outer edge fuel gas, so that the initial combustion temperature of the outer edge fuel gas can be further reduced and the combustion stroke of the outer edge fuel gas can be prolonged by the small outer circulation flue gas flow.

(5) The external circulation flue gas can be provided with circulation power by an independent fan, so that the very large full-flow throttling loss caused by a blower throttling suction mode is avoided, different amounts of external circulation flue gas can be supplied to different areas according to requirements, and the maximum effect is achieved by the minimum external circulation flue gas amount.

(6) The invention can greatly reduce the amount of externally circulating flue gas. The smaller flow of the external circulation flue gas can reduce the ventilation resistance, reduce the smoke discharge loss under high load and ensure the output of the boiler. The smaller flow of the external circulation flue gas can improve the concentration of the reaction gas in the hearth, and is also beneficial to improving the final combustion efficiency. The invention can control thermal NO under the conditions of lower power consumption of the fan, higher combustion efficiency and thermal efficiency_xAnd (4) generating to realize decoupling combustion.

Drawings

FIG. 1 is a schematic structural diagram of a decoupled gas burner according to an embodiment of the present invention;

fig. 2 is a side view structural diagram of a decoupling gas burner according to an embodiment of the present invention.

Wherein, 1-outer cylinder; 2-third-level wind cylinder; 3-outer edge external circulation flue gas pipe; 4-outer edge gas pipe; 5-gradually expanding short pipe; 6-a secondary wind barrel; 7-first-grade air cylinder; 8-a central gas pipe; 9-first-stage wind swirl blades; 10-inner side secondary wind swirl vane; 11-gas jet holes on the outer edge; 12-outer secondary wind swirl vanes; 13-two stage wind segmentation cylinder; 14-central gas tube end cap; 15-central gas jet hole; 16-an air inlet; 17-air chamber end plate; 18-edge internal circulation cover plate; 19-the wind chamber.

Detailed Description

It is to be understood that in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be taken as limiting the present invention. Furthermore, the terms "primary," "secondary," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "primary," "secondary," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

It should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "disposed," "connected" and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

In a specific embodiment, the invention provides a decoupling gas burner, as shown in fig. 1 and 2, which sequentially comprises a central gas pipe 8, a primary air cylinder 7, a secondary air cylinder 6 and an outer cylinder 1, which are coaxially arranged from inside to outside. An annular air chamber 19 is formed between the outer cylinder body 1 and the primary air cylinder body 7, an air chamber end plate 17 is arranged at one end, close to the hearth, of the air chamber 19, a frustum-shaped central gas pipe end cover 14 is arranged at one end, close to the hearth, of the central gas pipe 8, and at least one central gas spray hole 15 is formed in the outer peripheral surface of the central gas pipe end cover 14. An annular primary air channel is formed between the central gas pipe 8 and the primary air cylinder 7, and a primary air swirl vane 9 is arranged at one end of the primary air channel close to the hearth. An annular secondary air channel is formed between the primary air barrel 7 and the secondary air barrel 6, a secondary air swirl blade is arranged at one end of the secondary air channel close to the hearth, one end of the secondary air channel far away from the hearth is communicated with the air chamber 19, and the air in the air chamber 19 enters the secondary air channel and is sprayed into the hearth through the secondary air swirl blade. The installation inclination angle between the primary wind rotational flow blade 9 and the axis of the outer barrel 1 is larger than that between the secondary wind rotational flow blade and the axis of the outer barrel 1. The distance between the end face of the primary air cylinder 7 close to the hearth side and the end face of the outer cylinder 1 close to the hearth side is larger than the distance between the end face of the secondary air cylinder 6 close to the hearth side and the end face of the outer cylinder 1 close to the hearth side.

At least one outer edge burner is arranged at the annular cavity between the outer cylinder 1 and the secondary air cylinder along the circumferential direction. The outer edge combustor sequentially comprises an outer edge gas pipe 4, a gradually-expanding short pipe 5 and a tertiary air cylinder body 2 which are coaxially arranged from inside to outside.

An outer edge gas pipe cover plate is arranged at one end, close to the hearth, of the outer edge gas pipe 4, and at least one outer edge gas spray hole 11 is formed in the outer edge gas pipe cover plate.

The gradually-expanding short pipe 5 is of a thin-wall circular truncated cone structure, at least one air inlet 16 is arranged on the outer peripheral surface of the gradually-expanding short pipe 5, air in the outer tertiary air channel enters the inner tertiary air channel through the air inlet 16 and then is sprayed into the hearth from the large-diameter end, and the air inlet 16 is arranged close to the small-diameter end. The section diameter of the divergent short pipe 5 is gradually increased along the air inlet direction, and the divergent short pipe 5 comprises a large-diameter end close to the hearth and a small-diameter end far away from the hearth. A tertiary air channel is formed between the tertiary air cylinder 2 and the outer edge gas pipe 4, one end of the tertiary air channel far away from the hearth is communicated with the air chamber 19, an outer tertiary air channel is formed between the tertiary air cylinder 2 and the gradually-expanding short pipe 5, and a cavity formed by the inner wall of the gradually-expanding short pipe 5 is an inner tertiary air channel. An edge inner circulation cover plate 18 is arranged at one end of the outer tertiary air channel close to the hearth, the edge inner circulation cover plate 18 blocks part of gas outlets of the outer tertiary air channel, and further the edge inner circulation cover plate 18 blocks the gas outlets of the outer tertiary air channel close to one side of the outer cylinder 1.

The outer edge combustor also comprises an outer edge outer circulation flue gas pipe 3 sleeved outside the outer edge gas pipe 4, and an outer edge outer circulation flue gas channel is formed between the outer edge outer circulation flue gas pipe 3 and the outer edge gas pipe 4. One end of the outer edge outer circulation flue gas pipe 3 is in butt joint with the small-diameter end of the gradually-enlarged short pipe 5, furthermore, the outer diameter of the outer edge outer circulation flue gas pipe 3 is smaller than or equal to the inner diameter of the small-diameter end of the gradually-reduced short pipe, and gas in the outer side tertiary air channel enters the inner side tertiary air channel through a gap at the butt joint of the outer edge outer circulation flue gas pipe 3 and the gradually-reduced short pipe and then is sprayed into a hearth through the large-diameter end.

An annular secondary wind dividing barrel 13 coaxial with the outer barrel 1 is arranged in the secondary wind channel, the secondary wind channel is divided into an outer secondary wind channel and an inner secondary wind channel which are communicated by the secondary wind dividing barrel 13, an annular outer secondary wind channel is formed between the secondary wind dividing barrel 13 and the secondary wind barrel 6, and an annular inner secondary wind channel is formed between the secondary wind dividing barrel 13 and the primary wind barrel 7. One end of the outer secondary wind channel close to the hearth is provided with outer secondary wind swirl blades 12, and one end of the inner secondary wind channel close to the hearth is provided with inner secondary wind swirl blades 10. The installation inclination angle between the primary wind swirl blades 9 and the axis of the outer barrel 1 is larger than that between the inner secondary wind swirl blades 10 and the axis of the outer barrel 1, and the installation inclination angle between the inner secondary wind swirl blades 10 and the axis of the outer barrel 1 is larger than that between the outer secondary wind swirl blades 12 and the axis of the outer barrel 1. The distance between the end face of the primary air cylinder 7 close to the furnace chamber side and the end face of the outer cylinder 1 close to the furnace chamber side is larger than the distance between the end face of the secondary air segmentation cylinder 13 close to the furnace chamber side and the end face of the outer cylinder 1 close to the furnace chamber side, and the distance between the end face of the secondary air segmentation cylinder 13 close to the furnace chamber side and the end face of the outer cylinder 1 close to the furnace chamber side is larger than the distance between the end face of the secondary air cylinder 6 close to the furnace chamber side and the end face of the outer cylinder 1 close to the furnace.

In another embodiment, the invention provides a use method of the above-mentioned decoupling gas burner, which specifically includes the following steps:

central gas is sprayed into a hearth through a central gas pipe 8, primary air introduced from a primary air channel enters the hearth through primary air swirl vanes 9, and the central gas and the primary air are mixed and primarily combusted in the hearth;

the central gas accounts for 20-80% of the total gas amount of the decoupling gas burner. The primary air comprises central outer circulation flue gas and central air, wherein the volume ratio of the central outer circulation flue gas volume to the total air volume of the decoupling gas burner in a standard state is 0-10%, and the central air volume accounts for 5-30% of the total air volume of the decoupling gas burner.

(II) the gas in the air chamber 19 enters a secondary air channel to form secondary air, the secondary air is divided into two streams, one stream enters an outer secondary air channel to form outer secondary air, the outer secondary air passes through outer secondary air swirl blades 12 to enter a hearth, the other stream enters an inner secondary air channel to enter the hearth through inner secondary air swirl blades 10, and the primarily combusted central gas is mixed with the two streams of secondary air for combustion in the hearth;

the gas in the air chamber 19 comprises air chamber 19 external circulation flue gas and air in the air chamber 19, wherein the volume ratio of the air chamber 19 external circulation flue gas amount to the total air amount of the decoupling gas burner in a standard state is 0-15%; the air volume of the air chamber 19 accounts for 20-70% of the total air volume, and the air volume of the outer secondary air entering the outer secondary air channel accounts for 20-50% of the total air volume of the secondary air. The ratio of the total air quantity of the primary air and the secondary air to the theoretical air quantity required by the central fuel gas is 1-2.

(III) the gas in the air chamber 19 enters an outer tertiary air channel to form outer tertiary air, the outer tertiary air enters an inner tertiary air channel from the outer tertiary air channel through a gap at the joint of the outer edge outer circulation flue gas pipe 3 and the tapered short pipe or an air inlet 16 arranged on the tapered short pipe 5 to form inner tertiary air, the outer edge outer circulation flue gas is introduced from the outer edge outer circulation flue gas pipe 3, the inner tertiary air, the outer edge outer circulation flue gas and the outer edge fuel gas sprayed from the outer edge fuel gas pipe 4 are mixed and combusted at low temperature, and then the outer edge fuel gas and the outer tertiary air are mixed and combusted completely;

the inner tertiary air accounts for 0-60% of the total amount of the tertiary air, the ratio of the inner tertiary air to the theoretical air amount needed by the outer edge gas is 0-0.8, and the volume ratio of the outer edge external circulation flue gas to the total air amount of the combustor in a standard state is 0-10%.

Example 1

The embodiment provides a use method of a decoupling gas burner, which specifically comprises the following steps:

the central gas accounts for 20% of the total gas amount of the decoupling gas burner. The primary air comprises central outer circulation flue gas and central air, wherein the volume ratio of the central outer circulation flue gas volume to the total air volume of the decoupling gas burner is 1% in a standard state, and the central air volume accounts for 5% of the total air volume of the decoupling gas burner.

the gas in the air chamber 19 comprises the external circulation flue gas of the air chamber 19 and the air of the air chamber 19, wherein the volume ratio of the external circulation flue gas amount of the air chamber 19 to the total air amount of the decoupling gas burner in a standard state is 1 percent; the air volume of the air chamber 19 accounts for 20% of the total air volume, and the air volume of the outer secondary air entering the outer secondary air channel accounts for 20% of the total air volume of the secondary air. The ratio of the total air quantity of the primary air and the secondary air to the theoretical air quantity required by the central fuel gas is 1.

the inner tertiary air accounts for 5% of the total amount of the tertiary air, the ratio of the inner tertiary air to the theoretical air amount required by the outer edge gas is 0.1, and the volume ratio of the outer edge external circulation flue gas to the total air amount of the combustor under the standard state is 1%.

Example 2

the central gas accounts for 32% of the total gas quantity of the decoupling gas burner. The primary air comprises central outer circulation flue gas and central air, wherein the volume ratio of the central outer circulation flue gas volume to the total air volume of the decoupling gas burner is 3% in a standard state, and the central air volume accounts for 10% of the total air volume of the decoupling gas burner.

the gas in the air chamber 19 comprises the external circulation flue gas of the air chamber 19 and the air of the air chamber 19, wherein the volume ratio of the external circulation flue gas amount of the air chamber 19 to the total air amount of the decoupling gas burner in a standard state is 3 percent; the air volume in the air chamber 19 accounts for 30% of the total air volume, and the air volume in the outer secondary air entering the outer secondary air channel accounts for 26% of the total air volume in the secondary air. The ratio of the total air quantity of the primary air and the secondary air to the theoretical air quantity required by the central fuel gas is 1.2.

the inner tertiary air accounts for 16% of the total amount of the tertiary air, the ratio of the inner tertiary air to the theoretical air amount required by the outer edge gas is 0.25, and the volume ratio of the outer edge external circulation flue gas to the total air amount of the combustor in a standard state is 3%.

Example 3

the central gas accounts for 44% of the total gas quantity of the decoupling gas burner. The primary air comprises central outer circulation flue gas and central air, wherein the volume ratio of the central outer circulation flue gas volume to the total air volume of the decoupling gas burner is 5% in a standard state, and the central air volume accounts for 15% of the total air volume of the decoupling gas burner.

the gas in the air chamber 19 comprises the external circulation flue gas of the air chamber 19 and the air of the air chamber 19, wherein the volume ratio of the external circulation flue gas amount of the air chamber 19 to the total air amount of the decoupling gas burner in a standard state is 5 percent; the air volume in the air chamber 19 accounts for 40% of the total air volume, and the air volume in the outer secondary air entering the outer secondary air channel accounts for 32% of the total air volume in the secondary air. The ratio of the total air quantity of the primary air and the secondary air to the theoretical air quantity required by the central fuel gas is 1.4.

the inner tertiary air accounts for 27% of the total amount of the tertiary air, the ratio of the inner tertiary air to the theoretical air required by the outer edge gas is 0.4, and the volume ratio of the outer edge external circulation flue gas to the total air of the combustor under the standard state is 5%.

Example 4

the central gas accounts for 56% of the total gas quantity of the decoupling gas burner. The primary air comprises central outer circulation flue gas and central air, wherein the volume ratio of the central outer circulation flue gas volume to the total air volume of the decoupling gas burner is 7% in a standard state, and the central air volume accounts for 20% of the total air volume of the decoupling gas burner.

the gas in the air chamber 19 comprises the external circulation flue gas of the air chamber 19 and the air of the air chamber 19, wherein the volume ratio of the external circulation flue gas quantity of the air chamber 19 to the total air quantity of the decoupling gas burner in a standard state is 10 percent; the air volume in the air chamber 19 accounts for 50% of the total air volume, and the air volume in the outer secondary air entering the outer secondary air channel accounts for 38% of the total air volume in the secondary air. The ratio of the total air quantity of the primary air and the secondary air to the theoretical air quantity required by the central fuel gas is 1.6.

the inner tertiary air accounts for 38% of the total amount of the tertiary air, the ratio of the inner tertiary air to the theoretical air required by the outer edge gas is 0.55, and the volume ratio of the outer edge external circulation flue gas to the total air of the combustor under the standard state is 7%.

Example 5

the central gas accounts for 68% of the total gas quantity of the decoupling gas burner. The primary air comprises central outer circulation flue gas and central air, wherein the volume ratio of the central outer circulation flue gas volume to the total air volume of the decoupling gas burner is 9% in a standard state, and the central air volume accounts for 25% of the total air volume of the decoupling gas burner.

the gas in the air chamber 19 comprises the external circulation flue gas of the air chamber 19 and the air of the air chamber 19, wherein the volume ratio of the external circulation flue gas quantity of the air chamber 19 to the total air quantity of the decoupling gas burner in a standard state is 13 percent; the air volume in the air chamber 19 accounts for 60% of the total air volume, and the air volume in the outer secondary air entering the outer secondary air channel accounts for 42% of the total air volume in the secondary air. The ratio of the total air quantity of the primary air and the secondary air to the theoretical air quantity required by the central fuel gas is 1.8.

the inner tertiary air accounts for 49% of the total amount of the tertiary air, the ratio of the inner tertiary air to the theoretical air required by the outer edge gas is 0.7, and the volume ratio of the outer edge external circulation flue gas to the total air of the combustor under the standard state is 9%.

Example 6

the central gas accounts for 80% of the total gas quantity of the decoupling gas burner. The primary air comprises central outer circulation flue gas and central air, wherein the volume ratio of the central outer circulation flue gas volume to the total air volume of the decoupling gas burner is 10% in a standard state, and the central air volume accounts for 30% of the total air volume of the decoupling gas burner.

the gas in the air chamber 19 comprises the external circulation flue gas of the air chamber 19 and the air of the air chamber 19, wherein the volume ratio of the external circulation flue gas quantity of the air chamber 19 to the total air quantity of the decoupling gas burner in a standard state is 15 percent; the air volume in the air chamber 19 accounts for 70% of the total air volume, and the air volume in the outer secondary air entering the outer secondary air channel accounts for 50% of the total air volume in the secondary air. The ratio of the total air quantity of the primary air and the secondary air to the theoretical air quantity required by the central fuel gas is 2.

the inner tertiary air accounts for 60% of the total amount of the tertiary air, the ratio of the inner tertiary air to the theoretical air amount required by the outer edge gas is 0.8, and the volume ratio of the outer edge external circulation flue gas to the total air amount of the combustor under the standard state is 10%.

The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.

Claims

1. A decoupling gas burner is characterized by comprising a central gas pipe, a primary air cylinder, a secondary air cylinder and an outer cylinder which are coaxially arranged from inside to outside in sequence;

an annular air chamber is formed between the outer cylinder and the primary air cylinder, and an air chamber end plate is arranged at one end of the air chamber close to the hearth;

one end of the central gas pipe close to the hearth is provided with a frustum-shaped central gas pipe end cover, and the peripheral surface of the central gas pipe end cover is provided with at least one central gas spray hole;

an annular primary air channel is formed between the central gas pipe and the primary air cylinder, and a primary air swirl blade is arranged at one end of the primary air channel close to the hearth;

an annular secondary air channel is formed between the primary air barrel and the secondary air barrel, a secondary air swirl blade is arranged at one end of the secondary air channel close to the hearth, one end of the secondary air channel far away from the hearth is communicated with the air chamber, and the air in the air chamber enters the secondary air channel and is sprayed into the hearth through the secondary air swirl blade;

the mounting inclination angle between the primary wind rotational flow blade and the axis of the outer barrel is larger than that between the secondary wind rotational flow blade and the axis of the outer barrel;

at least one outer edge burner is arranged at the annular cavity between the outer cylinder and the secondary air cylinder along the circumferential direction; the outer edge combustor sequentially comprises an outer edge gas pipe, a gradually-expanding short pipe and a tertiary air cylinder body from inside to outside, wherein the outer edge gas pipe, the gradually-expanding short pipe and the tertiary air cylinder body are coaxially arranged.

2. The decoupling gas burner of claim 1, wherein the distance from the end surface of the primary air cylinder on the side close to the furnace to the end surface of the outer cylinder on the side close to the furnace is greater than the distance from the end surface of the secondary air cylinder on the side close to the furnace to the end surface of the outer cylinder on the side close to the furnace.

3. The decoupled gas burner of claim 1, wherein said diverging neck is a thin-walled circular truncated cone, the diameter of the cross section of said diverging neck increases gradually along the direction of the gas inlet, said diverging neck includes a large diameter end near the furnace and a small diameter end far from the furnace.

4. The decoupled gas burner of claim 1, wherein a tertiary air passage is formed between the tertiary air cylinder and the outer edge gas tube.

5. The decoupled gas burner of claim 4, wherein an end of the tertiary air duct remote from the firebox communicates with the plenum.

6. The decoupled gas burner of claim 4, wherein an outer tertiary air passage is formed between the tertiary air cylinder and the divergent stub, and a cavity formed by the inner wall of the divergent stub is an inner tertiary air passage.

7. The decoupled gas burner of claim 6, wherein an edge inner circulation cover plate is disposed at an end of the outer tertiary air channel close to the furnace, and the edge inner circulation cover plate blocks a part of gas outlets of the outer tertiary air channel.

8. The decoupled gas burner of claim 7, wherein said edge inner circulation cover plate blocks the gas outlet of the outer tertiary air channel on the side near the outer cylinder.

9. The decoupling gas burner of claim 1, wherein the outer edge burner further comprises an outer edge outer circulation flue gas pipe sleeved outside the outer edge gas pipe, and an outer edge outer circulation flue gas channel is formed between the outer edge outer circulation flue gas pipe and the outer edge gas pipe.

10. The decoupled gas burner of claim 9, wherein one end of said outer peripheral outer recirculation flue pipe abuts a reduced diameter end of said diverging neck.

11. The decoupling gas burner of claim 10, wherein the outer diameter of the outer edge outer circulation flue pipe is smaller than or equal to the inner diameter of the small diameter end of the tapered short pipe, and gas in the outer tertiary air channel enters the inner tertiary air channel through a gap at the joint of the outer edge outer circulation flue pipe and the tapered short pipe and is then injected into a hearth through the large diameter end.

12. The decoupling gas burner of claim 6, wherein the outer periphery of the divergent short pipe is provided with at least one gas inlet, and gas in the outer tertiary air channel enters the inner tertiary air channel through the gas inlet and is then injected into the hearth through the large-diameter end.

13. The decoupled gas burner of claim 12, wherein said inlet port is disposed proximate to said small diameter end.

14. The decoupled gas burner of claim 1, wherein a peripheral gas tube cover plate is disposed on an end of the peripheral gas tube adjacent to the firebox.

15. The decoupled gas burner of claim 14, wherein said outer edge gas tube cover plate is formed with at least one outer edge gas orifice.

16. The decoupled gas burner of claim 1, wherein an annular secondary air splitter cylinder is disposed within said secondary air passage and is coaxial with said outer cylinder.

17. The decoupled gas burner of claim 16, wherein said secondary air splitter barrel splits the secondary air passage into an outer secondary air passage and an inner secondary air passage in communication, said secondary air splitter barrel and said secondary air barrel forming an annular outer secondary air passage therebetween, said secondary air splitter barrel and said primary air barrel forming an annular inner secondary air passage therebetween.

18. The decoupled gas burner of claim 17, wherein said outer secondary air passage has outer secondary air swirl vanes disposed at an end thereof adjacent to said firebox.

19. The decoupled gas burner of claim 17, wherein said inner secondary air passage has inner secondary air swirl vanes disposed at an end adjacent to the furnace.

20. The decoupled gas burner of claim 19, wherein the setting angle between the primary wind swirler vanes and the outer barrel axis is greater than the setting angle between the inner secondary wind swirler vanes and the outer barrel axis, and the setting angle between the inner secondary wind swirler vanes and the outer barrel axis is greater than the setting angle between the outer secondary wind swirler vanes and the outer barrel axis.

21. The decoupled gas burner of claim 16, wherein the distance from the end surface of the primary air duct on the side close to the furnace to the end surface of the outer duct on the side close to the furnace is greater than the distance from the end surface of the secondary air dividing duct on the side close to the furnace to the end surface of the outer duct on the side close to the furnace, and the distance from the end surface of the secondary air dividing duct on the side close to the furnace to the end surface of the outer duct is greater than the distance from the end surface of the secondary air duct on the side close to the furnace to the end surface of the outer duct.

22. A method of using the decoupled gas burner of any of claims 1-21, the method of using comprising:

23. The use method according to claim 22, wherein the use method specifically comprises the steps of:

(III) the gas in the air chamber enters an outer tertiary air channel to form outer tertiary air, the outer tertiary air enters an inner tertiary air channel from the outer tertiary air channel through a gap at the joint of an outer edge outer circulation flue gas pipe and a tapered short pipe or an air inlet arranged on a gradually-expanded short pipe to form inner tertiary air, the outer edge outer circulation flue gas pipe is introduced into outer edge outer circulation flue gas, the inner tertiary air, the outer edge outer circulation flue gas and outer edge fuel gas injected by an outer edge fuel gas pipe are mixed and combusted at low temperature, and then the outer edge fuel gas and the outer tertiary air are mixed and combusted.

24. The use of claim 23, wherein said core gas in step (i) comprises 20% to 80% of the total gas content of the decoupled gas burner.

25. The use of claim 23, wherein said primary air comprises central outer circulation flue gas and central air.

26. The use method according to claim 25, wherein the volume ratio of the central outer circulation flue gas volume to the total air volume of the decoupling gas burner in a standard state is 0-10%.

27. The use according to claim 23, wherein the central air volume of the primary air is 5% to 30% of the total air volume of the decoupled gas burner.

28. The use of claim 23 wherein the air in the plenum in step (ii) comprises flue gas circulated outside the plenum and plenum air.

29. The use method of claim 28, wherein the volume ratio of the air chamber external circulation flue gas volume to the total air volume of the decoupling gas burner is 0-15% in a standard state.

30. The use of the method according to claim 23, wherein the secondary air plenum air volume is 20% to 70% of the total air volume.

31. The use of claim 23 wherein said outside secondary air volume is between 20% and 50% of the total secondary air volume.

32. The use of the method according to claim 23, wherein the total air volume of the primary air and the secondary air is equal to or greater than the theoretical air volume required for the central gas.

33. The use method of claim 23, wherein the ratio of the total air quantity of the primary air and the secondary air to the theoretical air quantity required by the central fuel gas is 1-2.

34. The use of claim 23, wherein said medial tertiary air in step (iii) is between 0% and 60% of the total tertiary air.

35. The use of the method according to claim 23, wherein the inner tertiary air volume is less than the theoretical air volume required by the outer edge gas.

36. The use method of claim 23, wherein the ratio of the inner tertiary air volume to the theoretical air volume required by the outer edge gas is 0-0.8.

37. The use according to claim 23, wherein the volume ratio of the outer periphery circulation flue gas to the total air amount of the burner under the standard condition is 0-10%.