DE9002826U1 - Burner arrangement - Google Patents

Abstract

2.1. Known burner arrangements are designed for oil and gas burning operation. Burner arrangements for solid-fuel operation are as is generally known prefurnaces which operate with a poor degree of efficiency. 2.2. The invention proposes in particular a solid-fuel forced-draught burner which has a chute (11) for solid fuel to be burned, a soild fuel supply device (9) connected preferably on the underside to the chute, a turbulence chanber (12) arranged downstream of the chute (11) and a lateral burning-out pipe (13) following the turbulence chamber, it being possible additionally to provide a blower (14) for the controlled supply of lower air (1), secondary air (2), upper air (3) and outgoing air (4). <IMAGE>

Description

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Description

The invention relates to a burner arrangement with a combustion tube, in particular arranged in front of a boiler for the purpose of heating it.

Known oil and gas burners, so-called "blue flame"*, have a burner nozzle and a combustion chamber which can burn and may not provide optimal, low-emission combustion with the highest level of efficiency. Oil and gas burners are naturally not suitable for burning fast fuels _, particularly wood chips and shavings.

In order to burn solids, the state of the art provides for so-called pre-furnaces in a pre-arrangement of boilers, which are operated in the manner of a burner arrangement. During operation, the solid material supplied is burned in the pre-furnace, the flame of which is directed through a combustion tube onto the combustion chamber of a downstream boiler. This creates an undefined flame with a comparatively low temperature, combined with a high dust emission, i.e. with a comparatively high proportion of unburned parts. Pre-furnace operation is therefore associated with a comparatively low level of efficiency. Contamination, sooting and environmental pollution are high. The known pre-furnaces have a solids supply that does not allow pressure sealing on the inlet side. In accordance with the external atmospheric pressure, practically only constant pressure operation with reduced draft ratios of primary and secondary air is possible in the pre-furnace. Blower activation is not provided and would also be ineffective due to the constant pressure operation.

The object of the invention is to improve the above-mentioned state of the art by creating a burner arrangement with a combustion tube, which is simple in construction and at the same time

wcM has a good heating efficiency with low-emission combustion and can be used in a wide variety of ways.

The problem underlying the invention is solved

i ^r by the means indicated in the characterising part of claim 1.

The subject matter of the invention is advantageously further developed by the features of subclaims 2 to 30.

The essence of the invention is the creation of a comparatively compact solid fuel burner, which is characterized by

- a filling shaft for solid materials to be burned,

- a solids feed device connected to the filling shaft,

- a turbulence chamber downstream of the filling shaft, and

- a burnout pipe connected to the swirl chamber.

Since the solids feed device is directly connected to the filling shaft, it is particularly useful to provide a blower with a metering device for the controlled supply of air. The solids feed device preferably comprises a rotary valve or a solids screw conveyor, which opens into the underside of the filling shaft and extends to the grate of the filling shaft. In this case, an upwardly curved ramp is preferably provided at the end of the screw conveyor, which extends to the grate. An (electrical) ignition device is located under the ramp.

pin wo· (j'MUHitit e or f inilim<jr?'jf?mnß<? Construction underseal'?!.-dntsi.'. ¹ Ii compared to conventional pre-heating or underfeeding furnaces in that the solid material is pressed into the combustion chamber of the filling shaft designed as a gasification chamber by a screw conveyor or the like and then mixed in with primary and secondary air by means of a blower. Through the screw conveyor,

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»CiV/IICt XIII IDtTOLXCU &Lgr;&Ogr; J. U XSt., XOU KCXII nULMJLailU fiUIII CXII ^- free solid material on the aisle side is possible, and a perfect "overpressure operation" is possible in the filling shaft or gasification chamber, which has good draught conditions, particularly due to the blower.

The fan is expediently connected to an air distribution chamber located inside the burner arrangement, which supplies under-air or primary air via a first air duct to the underside of the filling shaft below the grate and secondary air via a second air duct essentially just above the grate of the filling shaft. A section of the

whereby the secondary air is optimally heated before entering the filling shaft.

In an advantageous development of the invention, the air distribution chamber has a connection for a third air duct, through which so-called upper air is fed to the top of the filling shaft, well above the grate. The inlet opening for the upper air into the filling shaft is preferably located on the side and supports the passage of the combustion air to the downstream swirl chamber in such a way that in the swirl chamber, on the one hand

a defined turbulence occurs and is equally /"' led through the swirl chamber to a downstream burnout pipe:

In a particularly advantageous development of the ^invention , the air distribution chamber has a further fourth air channel, which provides so-called comparatively cool outlet air.

Supply of the aforementioned outlet air cools the high-quality flame, which is subjected to a rotary movement (swirl), in the
Burnout tube, from a flame temperature of about 1100 ⁰ C to a flame temperature of 800 ⁰ C. This means that the heat from the burner arrangement
The emerging flame contains less NO, since the NO formation

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only occurs at 6 00 ⁰ C. Obviously, this results in
This latter measure will result in a low-pollutant
optimal environmentally friendly combustion.

The latter feature is very important, can also be implemented in other burner arrangements and
claims singular protection also for other embodiments.

All of the aforementioned air ducts for the supply of lower, secondary, upper and outlet air are at least partially equipped with adjusting screws in order to dose the supply air manually or automatically.

In the overall arrangement, the turbulence cannon preferably extends essentially in the transverse direction horizontally behind the filling shaft. The turbulence cannon
is designed in the form of a tube, one axial end of which is closed and the other axial end of which is arranged essentially concentrically to the downstream burn-out tube and connected to it. The diameter

x) the flue gas

The diameter of the tube of the swirl chamber is larger than the diameter of the burnout tube. This results in a bundling of the fuel as it enters the burnout tube. The division of the burnout tube is simple because there is an opening flange opposite the flame outlet, which allows the swirl chamber and the burnout tube to be clearly seen.

A defined swirl in the swirl chamber is set up in particular by the swirl chamber '.' having a pipe jacket opening, in particular with a tangential wall area connection to the filling shaft. The pipe jacket opening corresponds approximately to the width of the filling shaft, with the entrance of the burn-out pipe being located essentially at the level of the associated axial side of the pipe jacket opening of the swirl chamber.

In particular, guide plates are provided in the swirl chamber, which are preferably arranged in a helical manner on the inner circumference (with _the exception of the pipe jacket opening), whereby the guide plates are ...

Burnout pipes. As a result, flue gases directed from the filling shaft through the swirl chamber to the burnout pipe are not only subjected to swirling, but also to an axial force in the direction of the burnout pipe axis. As a result, a high-quality flame with a defined flow is created in and after the burnout pipe, which can be directed precisely to a downstream boiler at the desired location.

It is particularly useful if the burnout tube has several individual burnout tubes parallel to the axis.

In particular, three <.| 1 oichvert-nlte individual combustion tubes are provided on the circumference.

The burnout tube or the individual burnout tubes are made of a high-quality ceramic material such as silicon carbide. The tubes have a thin wall and reach a high ignition temperature very early in the start-up phase of a burner operation. Silicon carbide tolerates temperature changes and withstands aggressive gases. The component is also easy to replace.

Accordingly, the swirl cannon can also be made of silicon carbide or similar.

The material of the filling shaft or the pre-gasification chamber is preferably a fire-resistant e-concrete lining.

The burner arrangement has a compact cube or box shape. The base housing can have steel walls, with an external heat-insulating jacket being provided. Behind this there is a circumferential water jacket, which is connected to the downstream boiler.

The burner arrangement according to the invention enables in particular the automatic combustion of industrial waste and chips (carpentry material). The basic housing is designed in such a way that a variety of installation techniques are possible.

Overall, the water flow of the base housing is designed in such a way that a loss of radiation from the burner arrangement is prevented. The burner can be quickly regulated and is controlled by the boiler temperature. It has great flexibility in terms of the types of loading. In addition to underfeed loading, a drop-down loading is also possible.

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The filling shaft is fed from above through a feed opening with a closure. The advantages and disadvantages of the various types of feeding depend to a large extent on the fuel. If underfeed feeding is planned, the grate is recessed in the feed area to accommodate the end of the aforementioned ramp. The fuel is pushed up here. An extension of the material transport shaft beyond the grate results in optimal pre-drying and better loosening of the fuel. Overall, the design of the grate depends on the ash content and the degree of slagging of the fuel.

The function of the burner arrangement is described below.

When the burner assembly is started up, the screw conveyor is in operation, which is driven by a motor which in turn is controlled by the boiler temperature. The electrical ignition device is also in operation for around 10 minutes. The wood chips or shavings that are pushed forward begin to glow and are pushed further along the ramp into the filling shaft or pre-gasification chamber. There, the combustion air supplied via the fan causes primary air and secondary air to be burned. A level indicator or sensor in the form of a swivel lever is installed in the combustion chamber or filling shaft, which actuates a level switch to switch off the screw conveyor. The burner assembly works independently in a similar way to an oil burner, and any boiler output can be heated, even in the smallest low-load operation. This prevents the temperature from falling below the dew point, as well as the temperature in the boiler, whereby no corrosion occurs. The above-mentioned VnnV.stnf. f -

The blower burner can be operated fully automatically without supervision. The upstream rotary valve or similar provides a high level of protection against burnback. The practically obtained aerosol values are significantly below the values specified in the Federal Emissions Protection Ordinance.

The advantage of the pre-swirl chamber lies particularly in the start-up phase of the burner arrangement, since a good combustion can be achieved during the start-up phase . The fresh air-gas mixture is then also prepared for the burn-out section.

The invention is explained in more detail below using an embodiment with reference to the attached drawings, in which:

Fig. 1 in a schematic perspective broken view of a burner arrangement,

Fig. 2 the arrangement according to Fig. 1 in a schematic broken plan view,

Fig. 3 the arrangement according to Fig. 1 in a section A-A of Fig. 2,

Fig. 4 the arrangement according to Fig. ] in a section B-B of Fig. 2,

Fig. 5 a detail in the area of the entrance of the burnout tube similar to the sectional view of Fig.3,

Fig. f) a section CC of P ¹ Ig. ^r ), and

Fig. 7 shows a prospective optical view of the Gooseneck in a runner arrangement similar to Fig.i in a larger size.

According to the drawing, a burner arrangement 10 is provided for the automatic combustion of industrial wood chips and shavings (carpentry material).

The basic housing is designed in such a way that a ve: -chiedpn-like installation technique is possible.

The burner arrangement 10 essentially comprises a filling shaft 11 for solids to be burned, a solids feed device connected to the filling shaft 11, a turbulence chamber 12 arranged at the end of the filling shaft and a lateral combustion chamber 13 connected to the oil supply.

Furthermore, a blower 14 with a metering device for the controlled supply of combustion air is provided.

The fan 14 is connected to an air distribution chamber 15 located inside the burner arrangement, which supplies under-air 1 via a first air duct to the underside of the filling shaft and secondary air 2 via a second air duct closely above the grate 18 to the filling shaft in a cocurrent flow, with a section 17 of the second air duct leading directly past the vertical inner filling shaft wall 18 in order to set up optimal preheating of the secondary air.

The air distribution chamber 15 is also connected to a third air duct, which supplies upper air 3 to the top of the filling shaft 11 well above the grate 18 in a manner as will be described below. In the individual air ducts for lower air 1, secondary air 2 and upper air 3 there are dosing devices in

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&iacgr; Form of adjusting screws £, which by turning a

■| ^: Allow volume regulation. This means that during operation

I; the blower 4 flowing into the air distribution chamber 15

Dc-.ierluft 5 in a controlled manner to the individual areas <?-ss Püllschachts i 1 swaoks ..j.timierimg of combustion and flow.

f The blower 14 ensures a so-called "overpressure operation"

the combustion chamber in particular because the filling shaft 11 is tightly connected to the solids feed device 9 at the inlet side.

The solids feed device 9 is designed as a so-called underfeed feed according to the embodiment example in the drawing and provides a screw conveyor 26 for automatic feeding of the solids to be burned, industrial wood chips, chips or the like, which is motor-driven and controlled by the boiler temperature. The screw conveyor 26 is located essentially in a horizontal extension on the front and reaches below the grate 16 into the burner arrangement 10, with an upwardly curved ramp 27 being provided closely adjacent to it, which is guided upwards to a recess in the grate 16 ' . The material is pressed through the screw to the top of the filling shaft, whereby an electrical ignition device 28 is provided under the ramp 27, which is in operation for about 10 minutes in the start-up phase of the burner arrangement, so that the supplied chips, wood chips or the like begins to glow and the primary and secondary air supplied by the blower 14 is brought to combustion in the filling shaft or pre-gasification chamber.

In the filling chamber 11 there is a central level sensor 8 with a pivoting lever 29, which is located on the side of the filling

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The screw 29 is designed as a so-called fixed float -O in such a way that when the fill level increases, the float moves upwards and the swivel lever 29 is swiveled. When the swivel lever 29 is swiveled upwards , it comes into engagement with a level switch 7 which switches off the screw conveyor 26. If the fill level in the filling shaft 11 falls, the screw conveyor 26 is put back into operation.

The height of the level switch 7 is adjustable to set different filling levels. The height of the level sensor 8 can also be adjusted accordingly. Of course, the screw conveyor 28 is only put into operation when the boiler temperature has dropped accordingly.

In addition to the above-mentioned underfeed loading, it is also possible to feed the filling shaft 11 by dropping it from above, since an access opening 3i is provided on the top of the filling shaft, which extends upwards in the shape of a spike. The upper access opening 31 has an upper closure, which has an insulating layer on the underside (which is not shown in the drawing).

The burner arrangement is constructed in a compact cube or box shape and has an outer heat-isolating jacket 32, which is connected on the inside by a circumferential water jacket 33, which is connected to a heating boiler (not shown) via a connection 34. Behind the filling shaft 11, in a horizontal transverse arrangement, there is the swirl chamber 12, which is designed in the form of a tube, &agr;&thgr;&Xgr;-&ogr; on oi no flyial cdi t-o ^arcrihl nccan -Jet- &Ggr;&idigr;&tgr;&ogr;&Lgr;&eegr;&Ggr;?&thgr;"»~&ogr;&Agr;&udigr;&iacgr;&lgr;&Igr;&mdash;

The side of the pipe is open and is connected to the inlet 19 of the coaxial burnout pipe 13, whose three individual burnout pipes 25, evenly distributed around the circumference, are directed towards the combustion chamber of the boiler (not shown). The individual burnout pipes 25 are made of silicon carbide and have a thin wall, which reaches a high ignition temperature early on when the boiler is put into operation. Silicon carbide tolerates temperature changes and withstands aggressive gases. The component is also easy to replace.

The inlet 19 of the burn-out tube 13 has an annular channel 23, which is shown in greater detail in Figs. 5 and 6. The annular channel 23 is connected on the inlet side to a fourth air channel, which is connected to the aforementioned air distribution chamber 15 or to the aforementioned fan 14 in order to convey comparatively cool outlet air 4 to the inlet 19 of the burn-out tube 13 during operation, namely through axially parallel outlet openings 24, which establish a passage from the annular channel 23 to the inlet 19 of the burn-out tube 13. The outlet air 4 is pressed from the ring channel 23 at the outer edge of the individual combustion tubes against the flow of the combustion gas and only then becomes active in the individual combustion tubes in such a way that the flame temperature is reduced from approx. 1100 °C to 800 ^° C, which has a positive effect on the NO mixing, ie essentially reduces the NO formation.

The swirl chamber has a pipe jacket opening 21 in the direction of the filling shaft 11 approximately in the width of the filling shaft, whereby the upper horizontal edge 35 of the pipe jacket opening 21 enables a tangential inlet of the fuel gas from the filling shaft 11 into the swirl chamber 12.

The upper horizontal edge 3 ^r lies approximately in the upper extension of the vertical filling shaft wall 18.

During operation, a defined rotational movement or swirl of the combustion gas is generated in the swirl chamber 12, which continues up to the individual combustion tubes 25 of the burnout tube 13 and there ensures high-quality defi·

from the burnout pipe 13 can be directed in a targeted manner onto the combustion chamber of the downstream boiler.

The inlet 20 of the upper air 3 to the filling shaft 11 is located on the side of the burner arrangement 10 opposite the inlet 19 of the burnout pipe 13, so that the upper air 3 supports the axial flow of the combustion gas in the swirl chamber towards the burnout pipe 13.

On the inside of the casing of the swirl chamber 12, swirl guide plates 22 can be provided, which run in the direction of the burnout pipe 13 for the purpose of setting up an axial conveying component for the combustion gases flowing through.

The invention therefore creates a solid fuel blower burner, which has a drop shaft that can be fed from below or from above. The outer base unit is water-conducting, with the outer casing being cube-shaped. The fuel gas is injected into the swirl chamber tangentially with an effective swirl effect. The supply of the outlet air 4 enables a gradual burnout in the individual burner tubes. The individual burner tubes or the burnout tube are arranged laterally in a coaxial extension of the

Turbulence chamber behind the filling shaft 11 or degassing shaft. The combustion preparation is achieved with the aid of a blower 14, whereby the air can be optimally fed to the individual burner arrangement positions via an air distribution chamber 15, in particular by providing each air point with a metering throttle.

Claims (1)

- 1 Protection claims 1. Burner arrangement with combustion tube, in particular in front of a boiler for the purpose of heating it, characterized by - a filling shaft (11) for solids to be burned, - a solids feed device (9) connected to the filling shaft (11), - a swirling chamber (12) downstream of the filling shaft (11), and - a burn-out pipe (13) connected to the swirl chamber (12). 2. Burner arrangement according to claim 1,
characterized, that a blower (14), in particular with a metering device, is provided for the controlled supply of air. 3. Burner arrangement according to claim 2,
characterized, that the fan (14) is connected to an air distribution chamber (15) which is connected via a first air duct (1) to the underside of the filling shaft (11) below the grate (16) and via a second air duct (2) closely above the grate (16) to the filling shaft (11), the second air duct (2) leading in a section (17) close to a filling shaft wall (18). 4. Burner arrangement according to claim 2,
characterized, that the upper chamber (15) has a third opening (3) with a flat top and a filling shaft (11) . 5. Burner arrangement according to claim 2, characterized in that the air distribution chamber (15) is connected to the inlet (19) of the burnout pipe (13) via a fourth air duct (4). 6. Burner arrangement according to one of claims 2 to 5, characterized in that da·, the air ducts (1, 2, 3, 4) for supplying lower air, secondary air, upper air and outlet air at least partially have adjusting screws (6). 7. Burner arrangement according to one of claims 4 to 6, characterized in that that the inlet (20) of the upper air (3) to the filling shaft (11) is essentially opposite the inlet (19) of the burn-out pipe (13). 8. Burner arrangement according to one of claims 1 to 7, characterized in that the turbulence cannon (12) _extends essentially in the transverse direction horizontally behind the filling shaft (11). 9. Burner arrangement according to claim 7 or 8, characterized in that the turbulence cannon (11) essentially has the shape of a tube, one axial end of which is closed and the other end of which is arranged essentially concentrically to the burn-out tube (13) and connected to it, wherein in particular the diameter of the swirl chamber tube is larger than the diameter -of the burnout tube (13). 10. Burner arrangement according to claim 9, characterized in that that the swirl chamber (12) has a pipe jacket opening (21), in particular with a tangential wall area connection to the filling shaft (11), which has approximately the width of the filling shaft (11), the inlet (13) of the burnout pipe ( 13) being located essentially at the level of one () axial side of the pipe jacket opening (21). 'i . Br: neranoidnung according to claim > or 10, characterized in de'S the swirl chamber (12) has swirl baffles (22). 12. Burner arrangement according to claim 11, characterized in that the swirl guide plates (22) are arranged in a helical manner on the inner circumference of the swirl chamber (12) (with the exception of the pipe jacket opening) and . the screw pitch in the direction of the inlet (19) of the burnout tube (13). 13. Burner arrangement according to one of claims 5 to 12, characterized in that the fourth air channel in the region of the inlet (19) of the burn-out tube (13) has an annular channel (23) enclosing the burn-out tube, which in turn has a plurality of axially parallel outlet openings (24) around the inlet (19) of the burn-out tube (13). - ⁴ - 14. Burner arrangement according to one of claims 1 to 13, characterized in that the burn-out tube (13) has several axially parallel individual burn-out tubes, in particular three evenly distributed around the circumference '25). 15. Burner arrangement according to one of claims 2 to 14, characterized in that that the fan (14) is located on the burner assembly side opposite the burnout pipe (13). 16. Burner arrangement according to one of claims 1 to 15, characterized in that that the solids guide device is designed as an underfeed feed of the filling shaft (11) and has a motor-driven solids conveyor screw (26) or rotary valve. 17. Burner arrangement according to claim 16, characterized in that the conveyor screw (26) is arranged essentially horizontally in the transverse direction to the swirling chamber (12) and to the burnout pipe (13). 18. Burner arrangement according to claim 16 or 17, characterized in that at the outlet end of the conveyor screw (26) a curved ramp (27) extends to the filling chute grate (16). 19. Burner arrangement according to one of claims 16 to 18, characterized in that a solid fuel ignition device (2R) is provided at the outlet end of the conveyor screw (26). 20. Hronn^rntmrrinunfj nnnh one of the claims'· I to 19, cladurrh q^kennzf ¹ i.chneh, that a level sensor (8) and a level sensor or level switch (7) for limiting the filling level or solids are arranged in the filling shaft (11). 21. Burner arrangement according to claim 20, characterized in that the level switch (7) or level sensor (R) is arranged so as to be height-adjustable near or in the filling shaft (11). 22. Burner arrangement according to claim 2.0 or 21, characterized in that the level sensor (8) has a pivoting lever (29), the free end of which is designed as a solid float (30) and is located inside the filling shaft (M), wherein the pivoting lever (29) can be brought into engagement with the level switch (7). 23. Burner arrangement according to one of claims 1 to 22, characterized in that that the filling shaft (11) has an upper access opening (31) with closure. 24. Burner arrangement according to one of claims 1 to 23, characterized in that the arrangement is essentially box-shaped. 25. Burner arrangement according to one of claims 1 to 24, characterized in that the arrangement has an outer thermal insulation jacket (32). 26. Burner arrangement according to claim 25, characterized in that that a circumferential water jacket (33) is formed in the area of the inside of the heat insulating jacket (32). 27. Burner arrangement according to claim 26, characterized in that the circumferential water jacket (33) can be connected to a heating boiler. 28. Burner arrangement according to one of claims 1 to 27, characterized in that the filling shaft (11) is lined with refractory concrete or the like. 29. Burner arrangement according to one of claims 1 to 28, characterized in that the burnout tube (13) and/or the swirl chamber (12) is made of silicon carbide. 30. Burner arrangement according to one of claims 1 to 29, characterized in that that a control device is provided for driving the solid material feed device (9) and igniting the ignition device (28).