RU2433342C2 - BURNER WITH CENTRAL AIR JET AND METHOD TO REDUCE NOx EMISSION OF SPECIFIED BURNER (VERSIONS) - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: burner with a central air jet comprises the following components: an axial pipe that includes an axial area, besides, the axial pipe is plugged at one end and opened at the other end, a circular pipe that concentrically surrounds the axial pipe, and forms the first circular zone between them, a drum that concentrically surrounding the circular pipe, and forming the second circular zone between them, a wall of the burner zone that concentrically surrounds the drum and forms the third circular zone between them, a supply pipeline arranged radially between the axial pipe and the circular pipe, besides, the supply pipeline forms a channel for movement of fluids between the axial zone and an air box, the facilities for conditioning of a pulverised coal flow around a part of the supply pipeline enclosed into the first circular zone, and also a damper that controls the flow and is arranged in the supply pipeline. The axial zone comprises a flow-conditioning device. The first circular zone comprises a flow-conditioning device. The first circular zone comprises a deflector arranged along the flow in front of the plugged end of the axial pipe. The burner comprises facilities to supply pulverised coal into the first circular zone. The second circular zone and the third circular zone are connected via a channel of fluids movement with an air box. The burner comprises a blade in the second circular zone, a blade in the third circular zone and a device of air flow measurement and a damper in the second and third circular zones. The diameter of the axial zone makes mainly from 228 to 508 mm, and the diameter of the first circular zone is mainly from 381 to 762 mm. The diameter of the second circular zone makes mainly from 508 mm to 1016 mm. The diameter of the third circular zone makes mainly from 560 mm to 1270 mm.

EFFECT: invention makes it possible to reduce generation of NO_x.

26 cl, 4 dwg

Description

Field of Invention

The present invention relates to fuel burners and, in particular, to a new and convenient atomized coal burner, as well as to a method of burning with reduced formation of NO _x , in which oxygen is supplied directly to the center of the burner flame so that an internal zone is created inside the burner flame combustion with a high fuel content and accelerated fuel combustion.

State of the art

NO _x is a by-product from the combustion of coal and other fossil fuels. Environmental issues associated with the effects of NO _x have led to the adoption of laws on NO _x emissions, requiring a sharp reduction in NO _x emissions in industrial plants and power plants in some countries, including the United States. Existing industrial methods and apparatus for reducing NO _x emissions successfully reduce NO _x emissions compared to previous years, however, further developments that go beyond the currently known methods and apparatus are required to meet current NO _x emissions requirements.

A variety of low NO _x burners are commercially available that are widely used to burn atomized coal (RU) and other fossil fuels using a method that reduces NO _x formation compared to conventional burners. Examples of such burners are the DRB-XCL ^® DRB-4Z ^® burners from Babcock & Wilcox. A common feature of these and other burner designs is an axial coal nozzle surrounded by a plurality of air zones from which secondary air (BB) is supplied. In the process, atomized coal suspended in the primary air (PV) is injected into the furnace through an axial coal nozzle in the form of an axial jet with little or no radial deviation. The ignition of the sprayed coal is accompanied by the twisting of secondary air, which ensures the recirculation of hot gases around the incoming fuel stream.

As a rule, part of the secondary air enters the air zone in the immediate vicinity of the air nozzle and swirls to a relatively greater degree than the secondary air entering the other air zones in order to ensure ignition. The remaining secondary air from the burner is introduced through the air zones further from the center towards the periphery of the burner with less twisting, as a result of which it is slowly mixed into the burner flame, thereby providing conditions with a high fuel content in the base of the flame. Such conditions stimulate the formation of hydrocarbons that compete for available oxygen and serve to destroy NO _x and / or inhibit the oxidation of fuel-related or molecular nitrogen to NO _x .

NO _x emissions can be further reduced by staged combustion, in which oxygen is supplied to the burner for complete combustion in an amount below stoichiometric. An enriched fuel medium appears in the burner flame. The fuel-rich medium prevents the formation of NO _x , causing NO _x precursors to compete with unburned fuel in an oxygen-depleted environment. The subsequent combustion stage is provided by the excess oxygen supply to the boiler at a point above the burner, where the excess fuel burns at a lower temperature, thereby preventing the formation of thermal NO _x as a result of burning at a lower temperature outside the burner flame. Graduation also serves to reduce oxygen concentrations during combustion, which prevents the oxidation of nitrogen associated with the fuel (fuel NO _x ).

Oxygen for staged combustion is usually supplied in the form of air through staggered air inlets, commonly referred to as superflammable air inlets (OFA), in a system that uses low NO _x burners. US Pat. No. 5,697,306 (La Rue) and US Pat. No. 5,199,355 (La Rue), incorporated herein by reference, disclose low NO _x burners that can be combined with a further reduction in NO _x emissions. methods of staged combustion.

Unlike traditional burners, low NO _x burners tend to form long flames and create high levels of unburned fuel. A long flame is not always desirable, as it may be incompatible with the depth or height of the furnace and damage the operation of the boiler, leading to the flaming of the flame on the wall, slagging and / or corrosion of the boiler pipe.

A long flame occurs due to insufficient air supply to the fuel stream when it enters the furnace. Secondary air from the outer air zones of burners with low NO _x formation inefficiently penetrates the fuel stream located after these zones, resulting in unburned fuel remaining due to the absence of air along the axis of the flame. High levels of unburned fuel are undesirable both in furnaces with and without flame inlet air inlets. Unburned fuel in the form of unburned carbon and CO reduces the productivity of the boiler and increases operating costs, while unburned atomized carbon, due to its abrasiveness, can cause undesired erosion damage to the furnace itself.

Incomplete mixing of air with fuel in front of the “flameless air inlet” system can cause excessive amounts of unburned fuel to be stored up to the approach to the flameless air inlets. When large amounts of unburned fuel tend to burn with air near the area of the flameless air inlets, NO _x formation increase, thereby minimizing or minimizing the advantage of staged combustion with overflammable air inlets. there are difficulties with respect to the complete burning of the named fuel at or outside the flameless air inlets, as a result of which this fuel further reduces productivity and creates difficulties during operation.

Disclosure of invention

The present invention solves the above problems associated with inhibited combustion in typical burners with low NO _x formation and provides a new combustion device and method for burning combustible fossil fuels to further reduce NO _x emissions in industrial and domestic boilers.

The burner according to the present invention is designed to burn atomized coal (RU) or gaseous hydrocarbons. The present invention includes an axial zone concentrically surrounded by a first annular zone. From the first annular zone, fuel enters the burner at a predetermined speed so as to create a fuel stream exiting the burner and then forming a burner flame by combustion in the presence of oxygen. The axial zone provides a central air stream penetrating the burner flame along the internal axis. The central air stream provides oxygen along the central axis of the burner flame, directing the combustion of the flame from the inside out and while maintaining the entire fuel-rich environment at the base of the flame, which prevents the formation of NO _x .

The additional amount of oxygen coming from the second and third annular zones concentrically surrounding the first annular zone further reduces the formation of NO _x , thereby being a means of accelerating combustion. The conditioning flows of the device of the second and third annular zones aerodynamically prevent the expansion of the fuel stream. Within the framework of this aerodynamic obstacle, the swirling created by the air leaving the second and third annular zones creates an internal recirculation zone along the outer boundary of the flame zone, which prevents the formation of NO _x . The internal recirculation zone (SEC) causes the NO _x generated along the outer, air-enriched flame boundary to recycle back to the fuel-rich flame base. The higher flame temperature created by the combustion of the central air stream from the inside out to the outside causes the unburned hydrocarbon radicals to bind the oxygen present in the internal recirculation zone, thereby suppressing the formation of NO _x and reducing the NO content to the level of other nitrogen compounds. A wider and shorter flame envelope occurs when the flame temperature rises due to accelerated combustion of the fuel in the direction from the inside out and outside inward of the internal recirculation zone.

The problem is solved using a burner with a central air stream containing:

an axial tube enclosing an axial zone, the axial tube being plugged at one end and open at the other end,

an annular tube concentrically surrounding the axial tube and forming a first annular zone between them,

a drum concentrically surrounding the annular tube and forming a second annular zone between them,

the wall of the zone of the burner concentrically surrounding the drum and forming a third annular zone between them,

a supply pipe located radially between the axial pipe and the annular pipe, and the supply pipe forms a channel for the movement of fluids between the axial zone and the air box,

means for conditioning the flow of atomized coal around a portion of the supply pipe enclosed in the first annular zone, and

flow control damper located in the supply pipe.

It is preferable that the axial zone comprises a flow conditioning device.

The first annular zone comprises a flow conditioning device.

The first annular zone preferably comprises a deflector located downstream of the muffled end of the axial tube.

The burner may contain means for supplying atomized coal to the first annular zone.

The second annular zone and the third annular zone of the burner are connected through the channel for the movement of fluids with the air box.

The burner contains a blade in the second annular zone.

The burner may also contain a blade in the third annular zone.

It is preferable that the burner comprises an air flow measuring device and a damper in the second and third annular zones.

The burner contains a pipeline concentrically surrounded by an axial zone.

The diameter of the axial zone is preferably mainly from 228 to 508 mm, and the diameter of the first annular zone is mainly from 381 to 762 mm, and the diameter of the second annular zone is mainly from 508 to 1016 mm, and the diameter of the third annular the zone is mainly from 560 to 1270 mm.

The burner preferably comprises a conduit concentrically surrounded by an axial zone.

The problem is solved by a method of reducing NO _x emissions from a burner with a central air stream, in which:

creating a four-zone burner in which the innermost zone is an axial zone concentrically surrounded by a first annular zone, wherein the first annular zone is concentrically surrounded by a second annular zone and the second annular zone is concentrically surrounded by a third annular zone;

create an air box connected through a channel for the movement of fluids with the axial zone, the second annular zone, and also with the third annular zone;

supplying secondary air to the air box;

carrier gas containing atomized coal is supplied to the first annular zone;

carrier gas is removed from the first annular zone at a speed of mainly 915 m / min;

create a flame by burning ejected atomized coal together with secondary air ejected from the second and third annular zones;

create an air pocket with secondary air in the core of the flame by ejecting secondary air supplied to the axial zone at a speed significantly higher than the speed of the carrier gas,

ignite the flame from the inside with the secondary air located in the air pocket with the secondary air,

creating an internal recirculation zone by ejecting secondary air supplied to the second annular zone at a speed less than the velocity of the carrier gas, and also ejecting secondary air supplied to the third zone at a speed greater than the speed of the carrier gas; as well as

suppress NO _x emissions by recirculation in the flame of unburned coal, oxygen and NO _x radicals.

It is preferable that the secondary air discharged from the second annular zone is swirled, and the carrier gas discharged from the first annular zone is also spun, in addition, the secondary air discharged from the third annular zone is swirled and the secondary air discharged from the axial zone is swirled.

The problem is also solved by a method of reducing emissions of NO _x in a burner with a central air stream for burning atomized coal, in which:

creating a burner in which the axial zone is concentrically surrounded by the first ring zone, the second ring zone is concentrically surrounded by the first ring zone, and the third ring zone is concentrically surrounded by the second ring zone;

create an axial zone in which the first gas contains oxygen, and the first gas leaves the axial zone with a speed of mainly from 1520 to 3050 m / min;

create a first annular zone in which the carrier gas contains atomized coal, and the carrier gas exits the first annular zone at a speed of mainly from 915 to 1520 m / min;

create a burner in which the second gas contains oxygen, and the second gas leaves the second annular zone at a speed of mainly from 915 to 1370 m / min; as well as

create a burner in which the third gas contains oxygen, and the third gas leaves the third annular zone with a speed of mainly from 1680 to 2280 m / min.

It is preferable that the first gas is discharged from the axial zone at a speed of mainly from 1680 to 2280 m / min, and the carrier gas is discharged from the first annular zone at a speed of mainly from 1065 to 1372 m / min, and the second gas is removed from the second ring zone at a speed of mainly from 945 to 1189 m / min and a third gas is removed from the third ring zone at a speed of mainly from 1740 to 2040 m / min.

It is preferable that oxygen is supplied to the flame of the burner, wherein, in general, from 20 to 40% of the total amount of oxygen enters the first gas through the axial zone, mainly from 10 to 30% of the total amount of oxygen enters the second gas through the second annular zone and, mainly, from 40 to 70% of the total amount of oxygen enters the third gas through the third annular zone.

When implementing the method, at least one of the following gases included in the group of gases consisting of: first gas, second gas, third gas or carrier gas is twisted before reaching the burner flame.

It is preferable that atomized coal is burned in the carrier gas stream by a first gas in the direction from the inside of the stream, atomized coal is burned in the carrier gas stream by a second gas and a third gas in the direction outside the stream;

apply means to create a recirculation zone inside the burner flame;

inhibit NO _x formation and accelerate combustion by recirculating unburned coal and oxygen in the burner flame.

It is preferable that the flow conditioning means is used to condition the gas flow within at least one of the groups consisting of the axial zone, the first annular zone, the second annular zone and the third annular zone.

Various novelty features that characterize the present invention are detailed in the attached claims, which form part of the present disclosure. For a better understanding of the invention, its operational advantages and the particular benefits that can be obtained by its implementation, reference is made to the accompanying drawings and descriptive material by which preferred embodiments of the invention are illustrated.

Brief Description of the Drawings

Figure 1 is a sectional view of one of the embodiments of the present invention.

Figure 2 is a schematic view of one of the embodiments of the present invention, in which the arrows indicate the direction of flow of air and coal.

3 is an external view of an embodiment of a burner assembly of the present invention, indicating the position of the supply pipe 9.

Figure 4 is a schematic sectional view of one of the embodiments of the present invention, which shows the concentric zones of the present invention.

Description of preferred embodiments

In the drawings, in which, as a rule, the same positions denote the same or functionally similar elements in all views, Fig. 1 is a schematic sectional view of a burner described in accordance with the present invention. The axial pipe 6, which comprises the axial zone 25, is concentrically surrounded by the first annular pipe 3, forming a space between the two pipes defining the first annular zone 11. Between the part of the first annular pipe 3 and the axial pipe 6, the supply pipe 9 is radially located so that the axial the pipe 6 and the air box 51 are interconnected through a channel for the movement of fluids at the opposite ends of the supply pipe 9.

Figure 3 shows a top view of the supply pipe 9, radially located between at least part of the first annular pipe 3 and the axial pipe 6 (not shown in figure 3) so that the axial pipe 6 and the air box 51 are interconnected through the channel for the movement of fluids opposite ends of the supply pipe 9.

Figure 1 shows the pressurized supply of blowers (not shown) of secondary air preheated in air heaters (not shown) to the air box 51. In turn, the supply pipe 9 supplies secondary air from the air box 51 to the axial pipe 6 at a speed controlled by the damper 10. The device 12 for measuring the air flow determines the amount of secondary air passing through the supply pipe 9.

The atomizer (not shown) grinds coal, which is transported by primary air through a pipe connected to the elbow of the burner 2. An igniter (not shown) can be placed on the axis of the burner and pass through the elbow 2 and plug 5 into the axial tube 6.

Atomized coal and primary air (atomized coal / primary air) 1 pass through the elbow 2 of the burner. Sprayed coal, as a rule, moves along the outer radius of the elbow 2 and concentrates in the stream along the outer radius at the exit of the elbow. Atomized coal first enters the annular zone 11 and collides with the deflector 4, which deflects the flow of coal into the plug 5 and disperses the coal. The axial pipe 6 is connected to the output side of the plug 5. The first annular pipe expands in the section 3A, forming a section 3B with a large diameter. Dispersed coal moves along the first annular zone 11, in which the grating device 7 provides a more uniform distribution of atomized coal before exiting it from the first annular zone 11 in the form of a fuel jet.

To disperse the coal in order to increase the speed with which it interacts with the secondary air, a flow conditioning device 30 can be used. The flow conditioning device 30 may consist of twisting blades and / or one or more difficult streamlined bodies to locally disturb flow and create a swirl .

To ensure a more uniform flow of secondary air when it leaves the axial zone 25 into the embrasure 8 of the burner and outward into the furnace (not shown) in the form of a central air stream, another air-conditioning device 13 can be installed. The air-conditioning device 13 can be blades, perforated plates or any other commonly used devices to provide a more uniform flow. In some cases, the flow conditioning device 13 may cause swirling toward central air to further accelerate ignition of the coal and reduce emissions.

An aspect related to the operator method of the present invention is the creation of a central air stream, inside which there is a jet stream of fuel exiting from the embrasure 8 and entering the furnace. The central air stream predominantly has a speed exceeding the speed of the fuel jet, thereby creating a velocity gradient inside the flame, which ignites the fuel in the direction from the inside out, using oxygen from the central air stream.

Optimum operating conditions occur when the primary air / atomized coal leaves the first annular zone at a speed of from about 915 to 1520 m / min and, more preferably, from about 1650 to 1350 m / min. Optimum operating conditions also occur when the secondary air leaves the axial zone 25 at a speed of from about 1520 to 3050 m / min and, even more preferably, from about 1680 to 2280 m / min.

Damper 15 controls the flow of additional secondary air to the burner assembly. In the open position, the damper 15 allows the secondary air to flow into the second annular zone 16 concentrically surrounding the first annular zone 11, where the second annular zone 16 is defined as the space between the pipe 3B and the drum 19. The damper 15 also allows the secondary air to flow into the third annular zone 17 concentrically surrounding the second annular zone 16, where the third annular zone 17 is defined as the space between the drum 19 and the outer wall of the zone of the burner 38. Damper 15 can be installed for predominant Rosselirovany secondary air into one of the zones through another zone or to supply smaller amounts of secondary air to both zones. An ignitor (not shown), if it does not pass through the pipe 6, can be optimally located in the annular zone 17.

Optimum operating conditions for using the three annular zones to supply secondary combustion air occur when about 20 to 40%, and more preferably about 25 to 35% of the total amount of oxygen introduced into the burner with secondary air is supplied through the axial zone 25. About 10 to 30% and, more preferably, about 15 to 25% of the total amount of oxygen introduced into the burner with secondary air is supplied through the second annular zone 16. About 40 to 70% and more preferably about 50 to 65% of the total amount of oxygen introduced into the burner with secondary air is supplied through the third annular air zone 17.

Air flow through the second annular zone 16 and the third annular zone 17 is measured using the device 18 for measuring air flow. Optimum operating conditions occur when the secondary air leaves the second annular zone 16 at a speed of from about 915 to 1370 m / min and, more preferably, from about 945 to 1190 m / min. In addition, when the secondary air leaves the third annular zone 17 at a speed of about 1680 to 2280 m / min, a speed of about 1740 to 2040 m / min is more preferred.

Optimum conditions for air movement occur when the inner diameter of the axial zone is about 9 "to 20" (about 228-508 mm), the inner diameter of the first annular zone is about 15 "to 30" (about 380-762 mm) , the inner diameter of the second annular zone is from about 20 "to 40" (about 508-1016 mm), and the inner diameter of the third annular zone is from about 22 "to 50" (about 558-1270 mm).

In order to swirl the secondary air before it leaves the second annular zone 16, adjustable blades 21 are arranged in the second annular zone 16. At the end of the second annular zone 16, other air distribution devices, such as perforated plates and inclined platforms, can also be installed. Stationary blades 22A and adjustable blades 22B spin the secondary air passing through the third annular zone 17. When the swirling air leaves the third annular zone 17, the blade 23, which can alternatively be installed in the middle of the exit from the air zone, deflects part of the air in the direction from primary combustion zone.

Figure 2 is a graphical depiction in which arrows indicate the directions of the secondary air flows and (atomized coal / primary air) 1.

In one alternative embodiment, a gas containing oxygen in a higher concentration than air may be used instead of all or a portion of the secondary air.

In another alternative embodiment, a hydrocarbon fuel other than atomized coal may be used as fuel.

Claims (26)

1. A burner with a central air stream containing:
an axial tube enclosing an axial zone, the axial tube being plugged at one end and open at the other end,
an annular tube concentrically surrounding the axial tube and forming a first annular zone between them,
a drum concentrically surrounding the annular tube and forming a second annular zone between them,
the wall of the zone of the burner concentrically surrounding the drum and forming a third annular zone between them,
a supply pipe located radially between the axial pipe and the annular pipe, and the supply pipe forms a channel for the movement of fluids between the axial zone and the air box,
means for conditioning the flow of atomized coal around a portion of the supply pipe enclosed in the first annular zone, and
flow control damper located in the supply pipe. 2. The burner according to claim 1, in which the axial zone contains a flow conditioning device. 3. The burner according to claim 1, wherein the first annular zone comprises a flow conditioning device. 4. The burner according to claim 2, in which the first annular zone contains a deflector located along the front of the muffled end of the axial tube. 5. The burner according to claim 3, containing means for supplying atomized coal to the first annular zone. 6. The burner according to claim 3, in which the second annular zone and the third annular zone are connected through the fluid flow channel to the air box. 7. The burner according to claim 6, containing a blade in the second annular zone. 8. The burner according to claim 7, containing a blade in the third annular zone. 9. The burner according to claim 7, containing a device for measuring air flow and a damper in the second and third annular zones. 10. The burner according to claim 1, containing a pipeline concentrically surrounded by an axial zone. 11. The burner according to claim 1, in which the diameter of the axial zone is mainly from 228 to 508 mm, and the diameter of the first annular zone is mainly from 381 to 762 mm. 12. The burner according to claim 11, in which the diameter of the second annular zone is mainly from 508 to 1016 mm 13. The burner according to claim 12, in which the diameter of the third annular zone is generally from 560 to 1270 mm. 14. The burner according to item 13, containing the pipe, concentrically surrounded by the axial zone. 15. A method for reducing NO _x emissions in a central air jet burner, wherein:
creating a four-zone burner in which the innermost zone is an axial zone concentrically surrounded by a first annular zone, wherein the first annular zone is concentrically surrounded by a second annular zone and the second annular zone is concentrically surrounded by a third annular zone;
create an air box connected through a channel for the movement of fluids with the axial zone, the second annular zone, and also with the third annular zone;
supplying secondary air to the air box;
carrier gas containing atomized coal is supplied to the first annular zone;
carrier gas is removed from the first annular zone at a speed of mainly 915 m / min;
create a flame by burning ejected atomized coal together with secondary air ejected from the second and third annular zones;
create an air pocket with secondary air in the core of the flame by ejecting secondary air supplied to the axial zone at a speed significantly higher than the speed of the carrier gas,
ignite the flame from the inside with the secondary air located in the air pocket with the secondary air,
creating an internal recirculation zone by ejecting secondary air supplied to the second annular zone at a speed less than the velocity of the carrier gas, and also ejecting secondary air supplied to the third zone at a speed greater than the speed of the carrier gas; as well as
suppress NO _x emissions by recirculation in the flame of unburned coal, oxygen and NO _x radicals. 16. The method according to clause 15, in which they spin the secondary air discharged from the second annular zone. 17. The method according to clause 15, in which spin the carrier gas discharged from the first annular zone. 18. The method according to clause 16, in which the twisted secondary air discharged from the third annular zone. 19. The method according to p, in which the secondary air is drawn off from the axial zone. 20. A method of reducing NO _x emissions in a central air jet burner for burning atomized coal, wherein:
creating a burner in which the axial zone is concentrically surrounded by the first ring zone, the second ring zone is concentrically surrounded by the first ring zone, and the third ring zone is concentrically surrounded by the second ring zone;
create an axial zone in which the first gas contains oxygen, and the first gas leaves the axial zone at a speed of mainly from 1520 to 3050 m / min;
create a first annular zone in which the carrier gas contains atomized coal, and the carrier gas exits the first annular zone at a speed of mainly from 915 to 1520 m / min,
create a burner in which the second gas contains oxygen, and the second gas leaves the second annular zone at a speed of mainly from 915 to 1370 m / min; as well as
create a burner in which the third gas contains oxygen, and the third gas leaves the third annular zone at a speed of mainly from 1680 to 2280 m / min. 21. The method according to claim 20, in which the first gas is discharged from the axial zone with a speed of mainly from 1680 to 2280 m / min, and the carrier gas is discharged from the first ring zone with a speed of mainly from 1065 to 1372 m / min. 22. The method according to item 21, in which the second gas is discharged from the second ring zone with a speed of mainly from 945 to 1189 m / min, and the third gas is discharged from the third ring zone with a speed of mainly from 1740 to 2040 m / min. 23. The method according to item 21, in which oxygen is supplied to the flame of the burner, and generally from 20 to 40% of the total amount of oxygen comes with the first gas through the axial zone, basically from 10 to 30% of the total amount of oxygen comes from the second gas through the second ring zone and mainly from 40 to 70% of the total amount of oxygen enters the third gas through the third ring zone. 24. The method according to item 23, in which twist before reaching the flame of the burner, at least one of the following gases included in the group of gases consisting of: first gas, second gas, third gas or carrier gas. 25. The method according to item 23, in which atomized coal is burned in the carrier gas stream by a first gas in the direction from the inside of the stream, atomized coal is burned in the carrier gas stream by a second gas and a third gas in the direction outside the stream;
apply means to create a recirculation zone inside the burner flame;
inhibit NO _x formation and accelerate combustion by recirculating unburned coal and oxygen in the burner flame. 26. The method according to item 23, which uses the means of conditioning the flow to condition the gas flow inside at least one of the groups consisting of the axial zone, the first annular zone, the second annular zone and the third annular zone.

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