KR100610725B1 - Round burner for burning pulverized fuel - Google Patents

Abstract

The powdered fuel, in particular the round burner for powdered coal combustion, has a cross section Q _SL and an inner diameter d _SL and has a central second air tube for introducing the second air volume S required for each round burner into the combustion furnace 10. 3) and the first mixture (15) concentrically surrounding the second air tube (3) and having an annular cross section and composed of first air or first gas and powdered fuel into the combustion furnace (10). A round burner for powder fuel combustion comprising a first mixture tube 3 and a method of operating the round burner (FIG. 1) are provided, wherein 0.8 kg to 10 kg high powder of powdered fuel per kg of air or gas is provided. for introducing a first mixture (15) represents the amount of fuel in the furnace 10, it becomes is given a reduced cross-section (Q _SLred), the second air cylinder (3), the reduced cross-section (Q _SLred) the second total amount of the second air flow (S) is required for each round of the burner (1) having a reference diameter (d _SLO) A group tube 3, the reference section based on the second air outlet speed (W ₀₎ through (Q _SLO) of the look as compared with a round burner design which is passed from the second air tube 3 to 10, the furnace And the reduced cross section Q _SLred is a part of which only 40% to 70% of the second air amount S required for each round burner 1 is introduced through the second air tube 3. Correlation d _SLred = 0.4 to 0.8 xd _SL0 based on the amount of air S ₁ represents the inner diameter d _SLred reduced according to _SL0 , wherein the second air outlet velocity from the second air tube 3 is the reference outlet velocity. Increasing from 20 to 100% of (W ₀ ), wherein at least one other second air tube 12 is disposed perpendicular to the first mixture tube 4 so that the amount of second air required per round burner 1 ( The remaining second air flow amount S _{2 (} 14) of S) flows into the combustion furnace 10.

Round burners, conical extensions, vortex devices, through conduits, angular momentum adjustment flaps, front walls, ignition zones, retaining rings, inlet casings, conduits

Description

Round burners for pulverized fuel combustion {ROUND BURNER FOR BURNING PULVERIZED FUEL}

1 is a longitudinal sectional view of a round burner according to the present invention.

FIG. 2 is a cross-sectional view of the round burner according to part A-A of FIG. 1.

FIG. 3 is a cross-sectional view of the round burner according to part B-B of FIG. 1.

FIG. 4 is the same as FIG. 1, but is a longitudinal cross-sectional view of a round burner of an alternative configuration.

5 is a cross-sectional view of the burner according to the C-C part of FIG.

FIG. 6 is the same as FIG. 1 but shows a second air supply and a first mixture of an alternative round burner.

7 is a partial longitudinal sectional view through a round burner in the region of nostril, in an alternative configuration.

8 is a partial longitudinal sectional view through a round burner in the region of the nostril, in an alternative configuration.

9 is a schematic front view of a round burner according to the invention in an alternative configuration.

10 is a radial cross-sectional view taken along the portion C-C of FIG. 9.

* Description of the main symbols in the drawing

1 round burner

2 burner neck or outlet

3 Second air tube (center)

4 First Mixture Tube

5 Second air tube inlet

6 1st air tube inlet

7 Second air tube outlet

8 First Mixture Tube Outlet

9 annular cross section between the second air tube and the first air mixture tube

10 combustion furnace

11 furnace wall

12 Second air tube (others)

13 Partially air volume flow S ₁ (center)

14 Partial Second Air Flow S ₂ (Near)

15 First mixture or powder flow

16 Supply line for the second air S ₁

17 Supply line for the second air S ₂

18 Supply line for first air or gas and fuel (first mixture)

Breeder of 19 round burners

20 Conical extension of the second central air tube

21 Conical Extension of First Mixture Tube

22 vortex devices

23 vortex devices

24 through conduit

25 Angular momentum adjustment flap

26 first mixture passage

27 Longitudinal axis of the additional second air tube

28 front wall

29 lighting zone

30 Outlet side part of central second air tube

31 retaining ring

32 inlet casing

33 conduit

34 maintenance segments

35 Flow-avoidance means or guidance devices

36 enclosing circle

37 combustion gases

The present invention relates in particular to a round burner for combusting fuel combustion, such as powdered coal, and a method of operating the same.

DE OS 102 01 558 discloses a round burner for combustible fuel combustion. In this known burner, all the second air to be put into each burner is supplied to the combustion chamber through a second air tube located in the burner, and the first mixture of the first air or the first gas and the pulverized fuel is second It is fed to the combustion chamber through a first mixture tube which concentrically surrounds the air tube and forms an annular cross section. Unlike the conventional approach, this new concept is to inject the second air into the center and surround the second air flow with the first mixture flow, and the pulverized fuel is in direct contact with the hot combustion gases generated in the combustion chamber during the combustion process. This has the advantage that rapid and reliable fuel ignition is achieved.

The round burner for pulverized fuel combustion known from DE OS 102 01 558 is applied for example for lignite combustion, which is substantially pulverized lower coal.

However, if such pulverized lignite or commonly used pulverized bituminous coal (including water, volatiles, and ashes of average content of water) is introduced into the combustion chamber, the first mixture in the first mixture tube is 1 kg of It has a fuel or coal dust content of about 0.1 kg to 0.6 kg per one air or first gas (feed gas) to lower the coal content in the conveying gas. In other words, the above-mentioned pulverized fuel to be charged requires the first mixture tube of the round burner to have a large amount of gas volume, thereby causing a large transfer cross section.

In a process in which less commonly used fuels, for example, low volatility pulverized bituminous coal (eg forge coal, lean coal or anthracite coal) or dry lignite (TBK) are burned. The higher coal content needs to be used for the first mixture tube of the round burner, which amounts to approximately 0.8 kg to 10 kg of ground fuel or coal per 1 kg of first air or first gas (feed gas). .

The high powder content in the first mixture reduces the volume of conveying gas and makes the conveying cross section of the first mixture tube of the round burner small. Since the volume of the conveying gas with high powder content is several times smaller than the volume of the conveying gas with low powder content, the conveying cross section of the first mixture tube is made several times smaller. This makes the annular cross section of the first mixture tube very small, which in many ways has a negative effect. For example, the pressure loss inside the first mixture tube is significantly increased, and above all, lowers the efficiency of the combustion system. In addition, the powdered coal is unevenly charged, causing uneven and inefficient combustion.

US 2003/0157451 A1 discloses particulate fuel burners with a low nitrogen oxide content. In the burners according to DE OS 102 01 558 described above, the combustion furnace receives annular air through a central tube and is annularly formed through a second tube concentrically surrounding the central tube or between both tubes of this known burner. Receive coal dust together with the first air through the space. The burner's second air nozzle design reduces nitrogen oxide emissions and generates forward jets (forward or rotary jets) of air introduced into the center at the exit of the furnace, thereby strongly injecting the particulate fuel and air introduced. Mix it up. US 2003/0157451 A1 does not mention the introduction of pulverized fuel, such as low volatility bituminous coal or dry lignite, into the furnace, so that the coal content in the first air flow or the conveying air flow needs to be higher. High pressure loss or poor dispersion of fuel in the furnace occurs.

DE 898 225 C discloses a burner for alternating or combined combustion of gas and coal. The burner includes a central tube for introducing first air or core air, another tube concentrically surrounding the first air tube for injecting powdered coal, and a second tube inside the furnace, concentrically surrounding the powdered coal tube. It has a typical design consisting of a third tube for conveying air. In addition to the typical design, the outer jacket of the burner tube of this burner houses an axially adjustable angle slider so that the amount of air supplied can be independently assigned to the central first or core tube and the outer second air tube. have. If the amount of first or core air in the center tube increases with the slider setting, the amount of second air introduced through the outer second air tube will thus decrease and vice versa. The coal dust flow entering the furnace is surrounded by the outer second air flow, thus preventing direct contact with hot combustion gases in the furnace. This prevents or delays the rapid heating and ignition of the coal fine particles introduced into the furnace.

It is an object of the present invention to provide a pulverized fuel burning round burner suitable for injecting a first mixture having a high pulverized fuel content into a combustion chamber and a method of operating the same.

The object is that a round burner is achieved by the features of claim 1 and a method of operation thereof by the features of claim 14.

Preferred embodiments of the invention can be found in the dependent claims.

The solution according to the present invention provides a round burner and its operation method having the following advantages.

The round burner according to the invention can efficiently and smoothly burn low volatility bituminous coal and dry lignite or heavy fuels, which are fuels not commonly used in coal coal combustion systems.

The first mixture flow with a high content of pulverized fuel can be introduced into the furnace with a significant reduction in pressure loss and a significant improvement in the pulverized fuel dispersion.

Hereinafter, exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

The accompanying drawings are provided for several embodiments of the round burner 1 according to the invention, for example individually, in combination for the furnace 10 of the steam generator or the utility steam generator of a generator (not shown). Or as a group. The round burner 1 is located on the wall of one or more furnaces of a steam generator (not shown) that borders the furnace 10 so that ground fuel (first mixture flow 15) is carried by the first gas or air. And second air 13 and 14 may be introduced into the combustion furnace by the round burner 1 and combusted. The combustion gases generated during this process are used to heat the steam generator operating medium, generally water and / or steam.

The round burner 1 has a central second air tube 3 arranged in the center of the longitudinal axis 19, the outlet 7 of the second air tube pointing in the direction of the furnace 10, whereby the second Air 13 is introduced into the combustion furnace 10. The second air tube 3 is concentrically surrounded by the first mixture tube 4 to form a gap or annular cross section between the second air tube 3 and the first mixture tube 4, thereby providing The first mixture 15 composed of one air or a first gas and pulverized fuel is introduced into the combustion furnace 10. The first mixture flow 15 may comprise combustion gas and water vapor, in addition to the ground fuel and the first air, which are essential for process reasons.

In the process of burning low volatility fuels such as forge coal, lean coal or anthracite coal, or other fuels with high calorie values such as dry lignite, they act as a transport medium for pulverized fuel. It is necessary to supply the combustion furnace 10 with a first mixture having a high pulverized fuel content of approximately 0.8 kg to 10 kg of pulverized fuel per kg of first air or gas. The reason for this is that when no fuel is used which is moderate, high volatility, or high ash content, the content of the ground fuel is transferred low, i.e. the amount of ground fuel in the range of 0.1 kg to 0.6 kg per kg of gas or air. This is because the ignition stability cannot be obtained in the combustion furnace into which the low volatility fuel fed to the furnace is injected. Compared with low volatile fuels, due to the first air or gas conveying medium having a high content of pulverized fuel, the volume of the conveying medium is correspondingly reduced (less conveying medium conveys more pulverized fuel), so that at the same conveying amount The annular cross section 9 is reduced.

However, a problem arises in that the cross section is reduced compared to a round burner in which heavy ash, such as ordinary or highly volatile bituminous coal, or lignite coal is introduced, which is pulverized per kilogram of conveying medium through the annular cross section 9. A first mixture containing fuel as low as approximately 0.1 kg to 0.6 kg is introduced into the furnace 10, thereby providing an annular cross-section 9 representing the velocity w of the second air outlet in the furnace 10. The dimension R of the gap or circular ring is so small that a significant pressure loss occurs inside the first mixture tube 4 in the round burner 1. This narrowed cross section also causes a problem with the transport of the first mixture flow 15. The dimension R of the gap relates to the radial distance between the inner and outer diameters of the circular ring 9.

When burning a mixture containing less than 0.1 kg to 0.6 kg of ground fuel per kg of conveying medium in a known round burner, the total amount of second air required per round burner is equal to the central second air tube 3. Is injected into the furnace 10 through the inner diameter d _{SLO of} the second air tube or the cross section Q _{SLO of} the second air tube and the outlet velocity W0 of the second air tube (for example 40 kPa). ) Is used as a reference variable. The above-mentioned problem is solved in the round burner 1 according to the present invention, and only a part of the second air amount S ₁ of 40% to 70% of the total amount S of the second air required for each round burner ₁ is provided. The second air volume S ₂ is introduced into the combustion furnace 10 through the second air tube 3, and the remaining second air amount S ₂ receives the additional second air tube 12 disposed around the first mixture tube 4. To pass. If this value and / or the second air outlet velocity W _{1 from} the second air tube 3 rises between 20% and 100% relative to the second air outlet velocity variable W ₀ , the second air tube 3 Can be significantly reduced in cross section (Q _SL )).

Numerically, the numerical value according to the invention refers to the diameter d _SLred , ie, the reduced cross section Q _SLred of the second air tube 3 is 40-80% smaller than the inner diameter d _SLO of the second air tube 3. To represent 0.4 to 0.8 times the second air tube inner diameter d _SLO given as a variable.

In the present invention, the annular cross-section 9 of the first mixture tube 4 moves radially in proximity to the round burner axis 19, whereby the constant annular cross-section Q _PR (ie, the constant first mixture yield) To generate a relatively large annular gap R, thereby reducing the pressure loss relatively considerably and smoothly introducing the first mixture into the furnace 10.

The round burner 1 according to the present invention has the advantage of increasing the combustion rate of the pulverized fuel charged to the center by the second air, thereby causing a strong and direct contact between the pulverized fuel and the high-temperature combustion gas ignitability This is improved. The first mixture flow 15 at which the content of the pulverized fuel is introduced at this time can be supplied with a significantly reduced pressure loss and a significantly improved dispersion of the pulverized fuel.

The stoichiometric quantity of air can be taken as the second amount of air S required for each round burner 1, and in the round burner 1 according to the invention at least two second air tubes 3, 12. Through the two partial second air flow (S ₁ , S ₂ ) is introduced into the combustion furnace 10. However, the sum of the required second air volume S introduced via the round burner 1, or the two partial second air volume flows S ₁ , S ₂ , is stoichiometric in the range of 0.3 to 1.0 of the stoichiometric air amount. The amount of air may be sufficient. In the final analysis, the selected (stoichiometric) range of the second amount of air S introduced per round burner 1 depends on the different amount of overfire introduced in different regions of the furnace 10, respectively. It should be selected according to the operation of.

1 to 3 show a round burner 1 according to the invention, in a preferred embodiment, the remaining second air volume S ₂ concentrically surrounds the first mixture tube 4 and the virtual circle 36. It is introduced into the combustion furnace 10 through four second air tubes 12a, 12b, 12c, 12d uniformly distributed in the phase. In this case, each of the second air tubes 12a, 12b, 12c, 12d is inclined at less than 45 ° with respect to the vertical projection surface of the longitudinal axis 19 of the round burner 1. In this embodiment, the remaining second air S ₂ 14 is to surround the first mixture flow 15 or the pulverized fuel one by one, during which hot combustion gas 37 is formed and supplied to the pulverized fuel. This further increases the heating rate and ignition.

4 and 5 show another variant of the round burner 1 according to the invention, in which the remaining second air S ₂ 14 passes through the two or more second air tubes 12a, 12b. ) Is put inside. At this time, the two or more second air tubes 12a and 12b are equally spaced above and below the first mixture tube 4, ie, vertically on the vertical projection surface of the longitudinal axis 19 of the round burner 1. The second air S ₂ (14) is added to the second air S ₁ (13) and the first mixture (15), which are introduced into the center, up and down half and mixed with them. The two second air flows achieve the advantages described above by inducing hotter combustion gases and injecting them into the pulverized fuel.

By adding the remaining second air S ₂ 14 the total amount of air S required per round burner 1 is provided and the fuel, ie the low volatility fuel, can be burned as desired. The cross section of the further second air tubes 12a, 12b, 12c, 12d may be round or angular as desired, and other shapes are possible.

The longitudinal axis of the further second air tube 12 is parallel to the longitudinal axis of the round burner as shown in FIGS. 1 and 4, and inclined with the longitudinal axis 19 in the direction of flow (not shown).

This makes it possible to inject the remaining second air volume S ₂ 14 into the ignition zone 29 of the round burner 1 so that optimum combustion takes place in the combustion furnace 10.

The first gas mixture 15 and some second air flow amounts S ₁ 13 can be introduced to the round burner 1 in different ways. 1, 2 and 4, the first mixture flow 15 is fed through a feed line 18 coaxially arranged with respect to the first mixture tube 4 and through the inlet 6 the first mixture tube ( 4), and is injected or injected into the combustion furnace 10 through the outlet (8). The mixture flow 15 passes through the annular cross section 9 between the first air tube and the second air tube 3.

The second air S ₁ (13) is introduced into the second air tube (3) via the inlet (5) via the supply line (16), and the supply line (16) is perpendicular to the second air tube (3). Arranged and encircling the first mixture tube 4, for example at intervals, and in a preferred embodiment of the invention, for example, another arrangement in which the first mixture 15 lies radially, tangentially or between Via three passages 24 across the annular cross-section 9, which conveys in the direction, ie the direction in which the second air S ₁ 13 is introduced into the combustion furnace 10 in the axial direction via the outlet 7. do. The second air tube 3 is sealed off from the outlet 7 by the front wall 28.

6 shows another method of supplying a first mixture flow 15 and some second air flow amount S ₁ 13. In this case, part of the second air flow amount S ₁ 13 is supplied to the second air tube 3 in the coaxial direction, and the supply line 16 is the second air at right angles or radially in the second air tube 3. S ₁ (13) is conveyed from the first mixture feed line (18) upstream of the flow medium. The first mixture flow 15 is fed to the first mixture tube 4 at right angles or radially via a feed line 18. In a preferred embodiment of this configuration, the annular cross section 9 does not need to be penetrated by the through channel 24 as in FIGS. 1 to 4.

The remaining second air volume S ₂ 14 introduced into the combustion furnace 10 through the second air tubes 12a, 12b, 12c, and 12d may be a separate supply line 17 (FIG. 6) or a supply line 16. Can be branched in all variations.

Each supply line is provided with a corresponding flap (not shown) to regulate some of the second air volumes S ₁ 13 and S ₂ 14.

In order to be able to change or optimize the position of the ignition zone in the burner throat 2, in one preferred embodiment, the second air tube 3 or the outlet side portion of the second air tube 3 ( 30 may be changed in the axial direction in the first mixture tube 4.

As a result, the outlet projection surface of the output side end 7 or the outlet side portion 30 of the second air tube 3 is mutually in relation to the outlet projection surface of the outlet side end 8 of the first mixing tube 4. It may be moved to another location. 1, 4, and 7, the outlet side end 7 of the second air tube 3 or the exit projection surface of the outlet side portion 30 of the first mixture tube 4 when viewed on a flow medium. It is located upstream by the count value k from the exit projection surface of the exit side end 8. Depending on the fuel and burner size, the measurement k can be up to 0.5 times the diameter d _SL of the second air tube 3, ie the two outlet side ends 7, 8 are the same according to FIG. 6. May be on plane. A projecting end of the second air tube 3 is also possible, i.e. the outlet projection surface of the outlet side end 7 of the second air tube 3 is viewed on the fluid medium of the first mixture tube 4 It is located downstream by the measured value k from the exit projection surface of the exit side edge part 8 of (circle).

In the current axially movable outlet side portion 30, the second air tube 3 consists of two parts, ie a fixed portion and an axially movable portion 30, the two portions overlapping each other. (FIG. 7).

As shown in FIG. 4, a conical extension 20 is provided at the end of the second air tube 3, or a retaining ring 21 is provided around the outside of the second air tube 3 as shown in FIG. 7. Thus, by structurally modifying the design of the outlet 7 of the second air tube 3, the ignition stability can also be affected, which reduces the annular cross section 9 of the first mixture tube outlet 8. Let's do it.

Given the conical extension 20 of the second air tube 3, the first mixture tube 5 is used to maintain a constant flow rate of the first mixture flow 15 within the cross section 9. The outlet of may also have a conical extension 21 (FIG. 4).

In one preferred mode regarding the operation of the burner 1 shown in FIG. 2, the central portion of the second air flow S ₁ 13 is essentially out of the helical feed line 16, the second air tube 3. It is introduced in contact with the second air tube 3 by an aligned through channel 24 and an angular momentum controller or flap 25, thereby imparting a rotational momentum to the flow amount 13, thereby providing a second air tube. It can be preserved as it is from the outlet to the furnace 10 without any other separate device in (3). Use the angular momentum controller 25 to control the angular momentum of the second air flow 13 until it is supplied without rotation while the second air flow amount 13 is radially introduced into the second air tube 3. It can affect or weaken it. By controlling the angular momentum controllers for all through channels 24 using a central spindle adjuster (not shown), for example, the same control can be set to set the same second air amount for each through channel 24.

The through channels 24 are each positioned at regular intervals in the annular cross section 9 such that the passages 26 for the first mixed flow 15 have the same cross section with the same transverse dimensions of the through channel 24. The first mixture flow 15 is constantly distributed.

In order to generate an extremely high first mixture velocity without unnecessarily reducing the cross section of the passage 26 in the region of the through channel 24, the selection width b of the through channel 24 is as narrow as possible for this purpose. The length is adjusted for the cross sectional requirements of the through channel 24.

The inlet casing 32, located radially outside the first mixture tube 4 and located in the region of the through channel 24, surrounds the tube 4 such that all current through channels 24 are filled with a second air. Extend beyond at least a part of it. The inlet casing 32 can be a rectangular casing, which forms a channel 33 between the outer wall of the inlet casing 32 and the tube 4. The conduit (33) formed around the outer periphery of the tube (4) by the inlet casing (32) preferably has a reduced depth inherent in the present specification, so that the side angle is greatly increased, so that the partial second air flow amount The velocity of S ₁ (13) is very constant and assigned to each individual through channel (24), and also assigned to the second air tube (3) when looking beyond the periphery. Among other methods, this requirement can be achieved using a good helical design for the inlet casing 32 according to FIG. 2.

Since the angular momentum caused by the inflow into the second air tube 3 can decrease with the length of the tube 3, it can be understood that the inflow of the second air does not occur too far from the burner neck 2. have. Distance L between the front wall of the inlet casing 32 facing the burner neck 2 (or corresponding to the boundary of the inlet hole 5 lying towards the burner neck 2) and the burner neck 2 Is satisfactory in the dimension of 0.5 to 10 times the diameter d _SL of the second air tube 3.

When the part of the second air flow amount S ₁ (13) is transported coaxially without being brought into contact with the second air tube (3), the part of the second air inflow amount (13) is installed inside the second air tube. The angular momentum can be imparted by the vortex device 22.

If ignition conditions are urgently needed, the first mixture flow 15 may also be provided with vortex devices 23, 34 inside the first mixture tube 4 or its annular cross section 9. The vortex apparatus can be located in a conventional position 23 as shown in FIG. However, the retention segment 34 described below can also be designed in such a way as to produce an angular momentum for the first mixture flow 15. This can be achieved by the retaining segment 34 extending beyond a particular axial length of the first mixture tube 4 and mounted at design (see FIGS. 9 and 10). Ignition stability is improved by vortexing the second air flow 13 when vortexing the first mixture flow 15.

In the round burner configuration shown in FIGS. 1 to 4, the first mixture is passed through the first mixture tube 4 while the annulus is distributed about the second air tube 3 with respect to the cross section 9. In order to prevent the flow from impacting the front wall 28 of the second tube, thereby preventing other strong corrosion from occurring on the front wall without causing strong fluctuations on the one hand, the front wall 28 The wear-resistant or stream-deflecting means 35 are installed upstream.

This means 35 may be a solid or hollow member, composed of known wear protection materials and which is a flat, hemispherical or streamlined triangle (see FIGS. 1 and 4).

According to FIG. 9, four retaining segments 34 can be arranged in the burner neck 2, for example each retaining segment 34 has a second air tube 3 and a first mixture tube 4. It extends radially in between and at an angle through some area of the annular outlet between the tubes 3, 4, and is installed at regular intervals. This also increases the contact surface between the elongated first mixture flow 15 and the extracted hot combustion gas 37, the first mixture 15, the second air 13, 14, and The combustion gas 37 is mixed more reliably. This improves ignition stability. The retaining segment can correspondingly be made of a sheet segment. However, as described above, it can penetrate in the axial direction and extend along the longitudinal direction and can be used as a vortex member herein.

The round burner according to the present invention is capable of efficiently and smoothly burning low volatility bituminous coal and dry brown coal or heavy fuel, which are fuels not commonly used in coal coal combustion systems, and having a high content of pulverized fuel. The mixture flow can be introduced into the furnace with a significant reduction in pressure loss and a significant improvement in the pulverized fuel dispersion.

Claims (14)

A central second air tube 3 having a cross section Q _SL and an inner diameter d _SL for introducing a second amount of air S required for each round burner into the combustion furnace 10, and the second air tube ( 3) concentrically surrounding, having a circular cross section, comprising a first mixture tube (3) for introducing a first mixture (15) consisting of first air or gas and pulverized fuel into the furnace (10); In pulverized fuels, especially round burners for coal dust In order to introduce the first mixture 15 having a high pulverized fuel content of 0.8 kg to 10 kg of pulverized fuel per kg of air or gas into the combustion furnace 10, the second air tube 3 was reduced. Given section (Q _SLred ), The reduced cross section Q _SLred is a reference cross section Q _SLO of the second air tube 3 in which the total amount of the second air amount S required for each round burner 1 has a reference inner diameter d _SLO . It is intended to be introduced into the combustion furnace 10 from the second air tube (3) at a reference second air outlet speed (W ₀ ) through, The reduced cross-section Q _SLred is a portion of the second air amount (only 40% to 70% of the second air amount S required for each round burner 1 is introduced through the second air tube 3). S ₁ ) represents the inner diameter d _SLred reduced according to the correlation d _SLred = 0.4 to 0.8 × d _SL0 , and the second air outlet velocity from the second air tube 3 is the reference outlet velocity W _0. Increase from 20 to 100% of One or more additional second air tubes 12 are arranged around the first mixture tube 4 to provide a residual second air flow amount S _{2 (} 14) of the second air amount S required for each round burner 1. Injected into the combustion furnace 10 Round burner for pulverized fuel combustion, characterized in that. Claim 2 was abandoned when the setup registration fee was paid. The method of claim 1, The projected surface of the outlet 7 of the second air tube is located upstream or downstream on the fluid medium with respect to the longitudinal axis or on the same projected surface as the outlet 8 of the first mixture tube. burner. Claim 3 was abandoned when the setup registration fee was paid. The method of claim 1, The outlet (7) of the second air tube comprises a conical extension (20), round burner for pulverized fuel combustion. Claim 4 was abandoned when the registration fee was paid. The method of claim 1, The outlet (8) of the first mixture tube comprises a conical extension (21), round burner for pulverized fuel combustion. Claim 5 was abandoned upon payment of a set-up fee. The method of claim 1, Said second air tube (3) comprises a swirling device (22). Claim 6 was abandoned when the registration fee was paid. The method of claim 1, Said first mixture tube (4) comprises a vortex device (22). The method according to any one of claims 1 to 5, Two additional second air tubes 12a, 12b, the two further second air tubes of the first mixture tube 4 in the vertical projection plane of the longitudinal axis 19 of the round burner 1; Crushed fuel combustion burner, characterized in that disposed on the top and bottom. The method according to any one of claims 1 to 6, Four additional second air tubes 12a, 12b, 12c, 12d are provided, the four second air tubes being constant on a vertical circular periphery located concentrically outward with the first mixture tube 4. Distribution and is disposed at an angle of 45 ° with respect to the vertical projection surface of the longitudinal axis (19) of the round burner (1). Claim 9 was abandoned upon payment of a set-up fee. The method according to any one of claims 1 to 8, Grinded, characterized in that the first mixture 15 can be fed to the first mixture tube 4 via a supply line 18 arranged coaxially or perpendicularly to the first mixture tube 4. Fuel burners. Claim 10 was abandoned upon payment of a setup registration fee. The method according to any one of claims 1 to 9, The second air 13 introduced into the second air tube 3 passes through the supply line 16 disposed coaxially or perpendicularly to the second air tube 3 to the second air tube 3. A burner for pulverized fuel combustion, which can be supplied. Claim 11 was abandoned upon payment of a setup registration fee. The method of claim 10, When the second air 13 is supplied perpendicular to the second air tube 3, the second air 13 passes through two or more through conduits 24 through the first mixture tube 4. A burner for pulverized fuel combustion, characterized in that it can be supplied to the second air tube (3) by means of. Claim 12 was abandoned upon payment of a registration fee. The method according to any one of claims 1 to 11, And a longitudinal axis (27) of said further second air tube (12a, 12b, 12c, 12d) is parallel to the longitudinal axis (19) of said round burner. Claim 13 was abandoned upon payment of a registration fee. The method according to any one of claims 1 to 11, The longitudinal axis (27) of the additional second air tube (12a, 12b, 12c, 12d) is inclined to the longitudinal axis (19) of the round burner when viewed in the flow direction. A method of operating a round burner in accordance with the features of claim 1.

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