EP1122495B1 - Device for incinerating biomass material in pulverized and solid form - Google Patents

Abstract

A blower device (48) produces a rotating fire circulation (90) in the combustion chamber (12). A build-up disc limits the blower device on the outflow side which it at least partly cuts off in front of the hot gases flowing back from the combustion chamber. A ring space radially surrounds the build-up disc and a mixture chamber (28) connects the combustion chamber with the flower device for flow purposes.

Description

TECHNICAL AREA

The invention relates to a device for burning of Organic dust and organic solids.

Biomass used for heating and for thermal disposal are available, for example, piece wood, shavings, Sawdust, wood chips, biofin dusts and biowaste. The progressive development of manufacturing technologies in the woodworking industry has not just shortened Workpiece life, but also to a considerable extent resulted in finer, dusty production waste in the Industry and craft today account for 70 to 80% (Percent) of wood residues. Another user wood burning is the bakery trade. The burning such residues is a challenge to the Feuerungsbauer. The regularly used rust with additional Primary air addition achieved in most combustion plants no longer the required low emission levels.

STATE OF THE ART

For heat recovery from biomass shear, Schrafrost-Schnecken-, Underfeed and dust injection furnaces as combustion systems known. With the previously known system technology becomes the residue biomass, which is predominantly lumpy accumulates, satisfactorily burnt.

From EP-A-0 473 618 a device of the preamble mentioned type, in which a helical gas flow is produced. For dusty fuels, the very dry and their structures in most cases as "einblaspflichtig" within the meaning of the German standard TRD 414 "Wood combustion on steam boilers" are classified or settled at least at the margins of this provision are, is with the known from this publication Zyklon-Einblasfeuerung a combustion in a rotating Movement generates, whereby the exhaust gas values CO and CO total get enough good. This device is with a Link head blower equipped. The power range corresponding Incinerators is 50 KW to 10,000 KW. The oil and gas combustion takes place predominantly in one in rotation transferred flame.

However, the remaining dust after combustion ash (residual dust) and _NOx still represent the greatest challenge when cyclone of the above or similar kind are to separate the residual dust from the hot gases. Many known systems are driven in load operation with too much excess air. This has the consequence that a large amount of flue gas flows through the boiler trains and thus the particular particulate matter from the ember bed is entrained in strands and blown out. Retrofitting with a hose or electrostatic precipitator is often considered the only, but very costly solution to "eliminate" these dusts. For plants below 2,000 KW, however, the initial cost of a corresponding filter already exceeds that of the boiler with firing.

A generic device of the type mentioned is known from EP-A-0 877 201. Between the helical gas flow generating blower device and the firing space fluidly connected thereto a channel-like mixing space formed to the Firebox opens. Comparable is also the EP-A-0 905 442.

PRESENTATION OF THE INVENTION

The invention is based on the object, starting from the As described above, a device for burning organic dust masses and organic solid matter specify the least polluting pollutants arise and be emitted.

This invention is characterized by the features of claim 1 given. Further developments of the invention are the subject of Dependent claims.

The downstream cross-sectional taper of the mixing chamber with the approximately central gas passage opening causes a Constriction of the mixed gas combustion air rotating in the mixing chamber. This constricted combustion air relaxes in the downstream firebox in one stable rotating fire roller. This fire roller can thereby targeted to the ember bed surface in the firebox be directed. This ultimately causes an optimal and rapid combustion of biomass in the firebox.

According to a development of the invention, the baffle plate formed in the present example as a heat shield may have a central opening. The gases flowing back from the combustion chamber into the mixing chamber are thus not completely deflected radially outwards on the baffle plate, but partly flow directly back into the blower device and then back into the mixing chamber via the annular space. This has a stabilizing effect on the rotating gas cylinder in the mixing chamber and can also be referred to as internal NO _x reduction.

Other features and advantages of the invention will become apparent the claims, the description and the drawing.

The device according to the invention means for the woodworking Industry and the bakery trade a big one technical progress in terms of thermal Energy generation and disposal of the residues.

Old and new biomass firings can be combined with the equipped device according to the invention or be retrofitted. Such a device according to the invention can with a through a frequency converter regulated link head blower according to EP 0 344 498 or with operated an impeller with perforated blading become.

The fresh air can be sucked in the shaft flange area and be used for engine cooling. Fresh air can also supplied to the blower area via separate intake openings, rotated and compactly accelerated. The according to rotating fresh air is then over a Annulus fed to the mixing chamber, in addition to from the Combustion chamber recirculated hot gas mixed and then the Supplied combustion process.

Through a spatially integrated combinatorial arrangement of blower area and mixing room can be a component in itself firmly connected "gas mixer" arise. Of the Firebox is fluidly gas mixer downstream. The transition area or border area between this gas mixer tap and the firebox preferably formed water-cooled. The coldest zone This gas mixer is located in the blower area. The warmer zone lies in the mixing room. The in the center of the mixing room Large-area emerging gas swirl nozzle is the prevailing Accumulation heat (about 900 ° C (degrees Celsius)) of the downstream Firing room exposed. The in the mixing chamber radially rotating gas mass generates in the center one very strong gas vacuum - eye of an eddy current - what to a backflow of CO-containing hot gas from the firebox leads to the inner baffle plate, which for the sake of a increased thermal load formed as a heat shield can be. The CO-laden substream heats the gases in the Mixing room at about 200 to 300 ° C (degrees Celsius). In the border area between mixing room and firebox lies the Temperature at about 500 ° C to 700 ° C (degrees Celsius). The energy once used for extraction and production the radial flow at the beginning of the process, which gradually Temperature increase of the gases with the physically released Expansion forces clearly show that the device an optimally continuous thermochemical combustion allows and ensures.

In a chain links arrangement in the link head blower is for generating the rotating air mass in an external Flue gas recirculation in the blower area comparatively little Fresh air needed. Such returned Rezigas (after Passed through a dust collector recycled cleaned hot flue gas), which is low in CO, can the Fan supplied to the annulus and the Cooling be passed over the heat shield. This stabilizes In addition, the radial flow in the mixing chamber. By concentric rejuvenation of the mixing chamber, the rotating mixed gas combustion air constricted and in compressed a spiral, coaxial radial flow specifically against the existing in the downstream firebox Emberbed be blown. It is, too possible, the mixed gas combustion air through an annular gap, in a the mixing chamber downstream limiting and a central opening having annular wall formed is not fired into the firebox to sack.

The communication zone created by the previously known link head blower the gas flow with the supply air or Ambient air is in the periphery of the annulus, on the inside of the chamber wall. The inventively created Communication zone is located with a significantly improved efficiency, however, at the end of the new existing mixing chamber according to a first embodiment of the invention in the cross-sectional area of the swirl nozzle acting gas passage opening in the region of a concentric Rejuvenation of the mixing room in its transition to Firing room, or according to another embodiment of the Invention in the annular gap of the gas passage opening containing annular wall.

An accelerated, compressed and constricted mixed gas combustion air becomes after passing the swirl nozzle itself suddenly relax in the downstream firebox. The around the eye, the center of the axis of rotation, stable rotating mixed gas gas roller (fire roller) can then purposeful over an ember bed surface; the periphery area This fire roller communicates with the carbonization gas above the ember bed in the flame area of the burnout zone and puts the whole volume of the hot gas mass in the firebox in a gentle, endlessly rotating movement. this leads to optimal and rapid release of methane gas the biomass. The remaining hydrocarbons of the charcoal hydrocarbon mixture can be added later Anneal hot gas area with the necessary residence time. The Combustion is especially optimal when the flame roller or fire roller little contact with the walls of the Firebox has.

1. die Flammentemperatur im Feuerungsraum wird abgesenkt,

2. die NO_x-Emission wird dadurch um ca. 30 % reduziert,

3. die Verbrennung kann je nach Brennstoff mit wenig Luftüberschuss betrieben werden,

4. der Staubaustrag wird reduziert und der Wirkungsgrad der Anlage verbessert.

The internal, central Rezigas feedback to the inner heat shield, thereby cooling it, and an additional or alternative admixture of the Req gas to the fresh air, mixed as combustion air before passing through the swirl nozzle, has the following advantages:

1. the flame temperature in the firebox is lowered,

2. The NO _x emission is thereby reduced by about 30%,

3. the combustion can be operated with little excess air, depending on the fuel,

4. the dust discharge is reduced and the efficiency of the system improved.

The hot gas roller thus produced leaves in the downstream, existing or retrofitted firing rooms a staufenlose Low-emission combustion of biomass in the control range from 30% to 100% with the necessary temperature mixing and dwell time too. By changing the cross sections from the inner heat shield or the swirl nozzle can the spiral radial flow in the firing areas the respective requirements, in particular the Location, shape and size of an ember bed to be adjusted. The each resulting spiral, rotating radial flow-type fire roller can last longer due to these changes and more constant or shorter and more unstable with respect to her Rotational form be designed.

The device according to the invention can be vertical, horizontal or diagonally, as injection and / or underfeed firing be educated.

By placing the device at a suitable location, for Example on the side over the ember bed in the flame area leaves the spiral-shaped combustion air roller deliberately over the ember bed surface. The dust content of the combustion material stays pressed against by the oppressive the ember bed fitting mixed gas fire roller in the ember bed lie. That means that in the over the ember bed rotating fire roller hardly any residual dust is present. Of the Residual dust discharge is therefore very low. The burning can thus be influenced and regulated in an optimal way become.

During the burning of lumpy wood in the oven, for example in a well-known wood oven (length about 2.5 m (Meters), width approx. 1.8 m, height approx. 0.25 m, without rust) At the same time the combustion chamber is the spiral rotating fresh air at the side of the ember bed in the outflow area fed to the burning biomass. The once produced rotating gas or fire roller is regardless of the orbital speed and is always present and visible.

Known roller or sliding grate firing, the fuel turn on burning and keep moving mostly large open spaces above the ember bed. At partial load operation Such systems will be the large-scale ember bed by reducing the combustion air bad with oxygen provided; a mixture takes place only conditionally. The outflow of unburned gases can thereby be practical can not be prevented. By the device according to the invention rehabilitated grate firing remains the other hand Fire roller optically very visible. During low load operation you can see that the ember bed is yellow to bright red preserves and does not die black, what a visible sign of optimal combustion. The Fire roller presses namely the existing in front of the ember bed Stowage heat against the ember bed and thus ensures even at partial load operation for adequate air supply.

In systems according to the invention, with a feed screw are equipped and where accordingly the Fuel is inserted, no rust is needed. A secondary air addition and part of a primary air addition can be done via the swirl nozzle, in one spirally rotating gas cylinder in the axial outflow direction towards the ember bed. Another primary air addition in the Front lower firebed area can be accessed via gas exhaust nozzles done in the front wall of the outer Heat shield can be placed. Your air jet can then end and act in the ember bed in the axial outflow direction, especially in the lower part of the ember bed.

In coarse or fine dust injection furnaces, the dust of the spirally rotating gas cylinder via blowing nozzles added. Dusts with a large amount of coarse particles are preferred tangential in the wall area - with 15 ° (old degree) to 45 ° (Altgrad) inclined to the center axis - blown. to Ignition usually has to be in the downstream cyclone furnace be placed a gas or Ölzündbrenner who the Combustion safety monitored. Finer, drier Dust content burns immediately. The thereby released Stowage heat, visible as a flame in the ignition area, stabilized the cracking phase of the coarser residual dust fraction in the Rotation diminishing, becoming more unstable, always visible permanent, endlessly rotating, cyclonic fire roller. However, with such Staubeinblasfeuerungen a nach-. Switched dust filter, especially for larger systems, be required.

BRIEF DESCRIPTION OF THE DRAWING

Fig. 1

einen Schnitt durch eine erfindungsgemäße Vorrichtung,

Fig. 2

einen Schnitt durch ein bei einer Vorrichtung ähnlich der von Fig. 1 zu verwendendes, mit einer zentralen Öffnung versehenes Hitzeschild,

Fig. 3

einen Querschnitt längs der Linie A - A der Fig. 1,

Fig. 4

eine Ansicht "x" der Vorrichtung gemäß Fig. 1,

Fig. 5

eine Vorrichtung ähnlich der von Fig. 1 mit einer zusätzlichen Staubeinblaseinrichtung,

Fig. 6

eine Seitenansicht eines Holzkessels mit einer Schnecken-Unterschubfeuerung und mit einer integrierten, erfindungsgemäßen Vorrichtung,

Fig. 7

einen Schnitt durch eine weitere Ausführungsform einer erfindungsgemäßen Vorrichtung,

Fig. 8

eine Vorrichtung ähnlich der von Fig. 5, aber mit einer andersartigen, dezentralen Staubeinblaseinrichtung und mit einem Ringspalt in der den Mischraum abströmseitig begrenzenden Ringwand, und

Fig. 9

einen Schnitt längs der Linie 9 - 9 von Fig. 8.

The invention will be described and explained in more detail below with reference to an embodiment shown in the drawing. Show it:

Fig. 1

a section through a device according to the invention,

Fig. 2

a section through a heat shield to be used in a device similar to that of FIG. 1, provided with a central opening,

Fig. 3

a cross section along the line A - A of Fig. 1,

Fig. 4

a view "x" of the device of FIG. 1,

Fig. 5

a device similar to that of FIG. 1 with an additional Staubeinblaseinrichtung,

Fig. 6

a side view of a wood boiler with a Schnecken-Unterschubfeuerung and with an integrated device according to the invention,

Fig. 7

a section through a further embodiment of a device according to the invention,

Fig. 8

a device similar to that of FIG. 5, but with a different, decentralized Staubeinblaseinrichtung and with an annular gap in the mixing chamber downstream limiting annular wall, and

Fig. 9

a section along the line 9 - 9 of Fig. 8.

WAYS FOR CARRYING OUT THE INVENTION

A firing system 10 is used for burning organic dust masses and organic solids. The furnace 10 has a firing space 12, in the solid masses 14 (Fig. 6) can be burned.

A gas mixer 20 produces a gas cylinder 90 and represents a compact unit, which in a in the Wall 22 of the furnace 10 existing breakthrough 24 is used gas-tight. The gas mixer 20 has an outer housing wall 26 which is in its central area is formed circular cylindrical and a mixing chamber 28th wrapped in a cylindrical shape. On her, referring to the Furnace space 12, side facing away from the housing wall 26th closed by a rear wall 30. In the rear wall 30 is a central opening in which a shaft 32 rotatably mounted is, via a motor drive 34 about the longitudinal axis 36 of the gas-mixing mixer 20 are set in rotation can. On the shaft 32 are in the present case two rings attached by chain links 38, 40, which together with the Shaft 32 can rotate about the axis 36. The wreaths are movably attached to the shaft 32. In the present example case are the chain links 38, 40 and each other movably formed.

In the area of the chain links 38, 40 projects through the Rear wall 30 guided through lead 42 into it. These Feed line 42 defines an intake 44 for in the Area of the chain links 38, 40 to be introduced fresh air and Rezigas. The range of chain links represents the Blower section 46 of the substantially of the chain links 38, 40 and the drive 34 existing blower 48.

Outflow side, in the transition area between the blower area 46 and the mixing chamber 28, is a centric heat shield 50 available. On its inflow side is the heat shield 50 surrounded by a housing 52. In this case 52 projects into a conduit 54, which the fan area 46th and the back wall 30 pierces. The opening 56 of this Line 54 provides a suction for fresh air and Rezigas dar. Fresh air and Rezigas can so through the Line 42 (in the fan section 46) and through the line 54 (in the region of the housing 52 of the heat shield 50) each initiated.

The housing 52 has opening slots 58 through which the in the housing 52 introduced mixture of fresh air and Rezigas can emerge radially in an annular space 60, the Heat shield 50 radially outwardly surrounds. The annulus 60 is so formed between the heat shield 50 and the housing wall 26 and adjusts the fluid connection to Mixing room 28 dar.

To the firebox 12 towards the gas mixer 20 ends with an annular wall 70 formed as an outer heat shield is. The annular wall 70 has a central opening 72. Die Inside the annular wall 70 is in a flowing transition connected to the housing wall 26. This on the ring wall 70th adjacent housing wall portion 78 is connected to the housing wall 26th integrally connected. The metallic in this case Housing wall 26 thus forms in the region of the annular wall 70 a inner lining of this annular wall 70. On the in Fig. 1st right side of this ring wall 70 is the Furnace space 12, in particular of FIG. 6 schematically can be seen.

In contrast to that shown in Fig. 1, full-surface Heat shield 50 is shown in the in Fig. 2 in section Heat shield 50.2 a central opening 62 available. This allows a certain flow compensation between the Blower area 46 and the mixing space 28 take place. Instead of an opening 62 can also be arranged a plurality of openings be.

In the illustrated in Fig. 5 furnace 10.5 are fed the bio-dust masses via a blowing-in line 18 (Arrow 16). The sparger 18 is in this embodiment Component of the gas mixer 20.

The injection line 18 protrudes largely centrally through the Mixing chamber 28 through and ends in the region of the opening 72nd With her other end, she pierces the heat shield 50 and the housing 52 and ends outside the rear wall 30th

The firing system 10 or 10.5 works following way:

By rotation of the chain links 38, 40 a rotating air roller is generated in the region of the annular space 60, which continues on the inside of the housing wall 26 through the mixing space 28 as a gas roller 90. In the region of the opening 72, this gas cylinder 90 experiences a central constriction (gas roller 90.2). In the region of the combustion chamber 12, this gas cylinder 90.2 relaxes more or less abruptly to the outside. As a result of the temperatures prevailing in the firing chamber 12, a radially expanding hot gas roller (fire roller) 90.4 is created which ends above the ember bed of the solid mass 14 (FIG. 6). Due to the strong rotation of this gas cylinder 90, 90.2, 90.4 forms in the region of its axis of rotation, a significant negative pressure. As a result, a gas backflow (arrow 100) is effected which returns CO laden hot gas as a partial flow from the firing chamber 12 into the region of the mixing chamber 28. This gas recirculation 100 heats the gases in the mixing chamber to about 200 to 300 ° C (degrees Celsius), the gases in the region of the opening 72 to about 500 to 700 ° C. In the area of the heat shield 50, the gas recirculation 100 is completely deflected outwards (arrows 104) and mixes with the gas cylinder 90. In contrast, in the heat shield 50. 2 (FIG 2), a central portion of the gas recirculation flow 100 into the blower section 46. In addition, fresh air and Rezigas is led into the annular space 60 through lines 42, 54 and from there also the gas roller 90 is fed. The CO fraction of the gas recirculation 100 reacts with the oxygen (O ₂ ) of the combustion air. The low-oxygen combustion air thus enables a combustion process with internal NO _x reduction. Finally, dust 16 can be fed through the injection line 18 of the gas roller 90.2 and thus also the hot gas roller 90.4 (FIG. 5).

In the region of the mixing chamber 28 prevail as a result of the supply line fresh air and Rezigas lower temperatures as in the area of the firing room 12. Also, in the Mixing chamber 28 an intimate mixing of the supplied fresh air and the Rezigases with the from the firing 12th back-flowed hot gas mixture instead. Together with the Arrangement of only having a central opening outer heat shield creates a very stable gas roller both in the area of the mixing chamber 28 and in the area of Feuerungsraumes 12, even at up to 30% reduced Partial load operation.

In the wall 70 are two more in the present case Openings 110 present (Fig. 4), through the air from the Mixing chamber 28 in the firing chamber 12 as a result of by the Gas roll 90 flow through the mixing chamber 28 generated gas flow can. The openings 110 are aligned so that this additionally directed into the firing chamber 12 gas flow (Primary air) in the direction of the solid mass 14 or whose ember bed 112 is directed.

In the embodiment shown in Fig. 7 is a compared to the embodiments shown in FIGS. 1 and 5 comparatively very thick wall 70.7 available. This allows a constricted longer in the flow direction permanent gas or fire roller 90.4 achieve.

In the furnace 10.8 shown in Fig. 8 is the in the above-described furnace 10 existing Ring wall 70 as relatively far into the firing 12th protruding pipe or channel piece 70.8 formed. In addition, between this piece of pipe 70.8 and the combustion chamber 12 limiting wall 22 an annular gap 116 available. The injection line, in the Fig. 5 in the Mixing chamber 28 protrudes, is 10.8 in this furnace 10.8 outside the gas mixer 20 available by protrudes through the wall 22 and outside of the pipe section 70.8 ends directly in the firing chamber 12. Your end Injection nozzle for introducing coarse and in particular also Fine dust in the firing chamber 12, and thus its outlet opening 118, is aligned in the firing chamber 12 that the dust 120 is parallel to a pipe section 70.8 concentric can flow out surrounding circular cylinder. there this dust 120 flows when leaving the outlet opening 118 obliquely to the longitudinal axis 36. In Fig. 8 is the direction the longitudinal axis 36 pointing direction component and in Fig. 9 in the right-angled directional component the dust movement shown schematically. On this way is an intimate mixing of this dust 120 with the outside of the pipe or channel piece 70.8 given to Forming Fire Roller 90.8, as below is described in more detail, without the blown Dust in terms of flow with the gas backflow (arrow 100) could collide.

Due to the annular gap 116 which is in the mixing chamber 28 itself forming gas roller 90 no longer constricted, like that in the above embodiments is the case. The on the outer housing wall 26.8 of the gas mixer 20 in Mixing space 28 existing gas roller 90 flows through rather the annular gap 116 and into the firing 12th into it. As in the previous embodiments is due to the training in the mixing chamber 28, by the rotation of the gas cylinder 90 caused negative pressure a gas backflow (arrow 100) from the combustion chamber 12 in causes the mixing chamber 28 in. Because of in the mixing room 28 existing rotating gas flow of the gas roller 90th The gas return flow is also set in rotation. The Gas backflow is schematized with a spin coil 100.8 shown. This CO laden gas backflow mixes in the mixing chamber 28 with through the rotating Chain links 38, 40 sucked fresh air and recycled Rezigas, as already described above.

This furnace 10.8 is based on the knowledge that a coarse and fine dust combustion no constriction of Gas roller, as described in Figures 1 to 7 is needed. By the direct derivation of the in the firebox 12 to the fire roller expectant gas roller 90.8 on the Annular gap 116 flows outside the combustion air Pipe or duct piece 70.8 in the firing room 12. The ignition of coarse and fine dust 120 takes place immediately after leaving the injection line 18.8 and thus after flowing out of the outlet opening 118. The in the rotating gas or fire roller 90.8 in the firing chamber 12 immediately released heat accumulation allows a fast and optimal combustion without Grobasche- and Slag formation. The firing chamber 12 is due to the ruling high temperatures fireproof.

The internal Rezigas recirculation and the NO _x reduction are carried out in the same manner as in the ember bed furnace described above in connection with FIGS. 1 and 7.

The externally recirculated flue gas with its oxygen content contributes all the more to the NO _x reduction, the more unburned hydrocarbons (CO) are present in the externally recirculated Rezigas.

Claims (19)

1. Apparatus (10, 10.5, 10.8) for burning biodust masses and biosolid masses (14, 16), having

   a combustion space (12)

   a blower (48) for generating a rotating fire vortex (90, 90.2, 90.4, 90.8) in the combustion space (12),

   a baffle plate which defines the blower on the outflow side, is designed as a heat shield (50, 50.2) and is intended for at least partly sealing off the blower (48) from hot gases flowing back from the combustion space (12),

   an annular space (60) radially surrounding the baffle plate,

   a housing wall (26, 26.8) surrounding the annular space (60) on the outside,

   a mixing space (28) between the combustion space (12) and the blower, via which mixing space (28) the blower is fluidically connected to the combustion space (12),

   characterized in that

   the mixing space (28), on the outflow side, has a cross-sectional constriction having an approximately central gas passage opening (72).
2. Apparatus according to Claim 1, characterized in that there is at least one central opening (62) in the baffle plate or in the heat shield (50.2).
3. Apparatus according to either of the preceding claims, characterized in that there are gas discharge openings (110) for air in the annular wall (70), defining the gas passage opening (72), of the mixing chamber (28) such that the air flow from these gas outlet openings (110) is directed towards the firebed (112) present in the combustion space.
4. Apparatus according to one of the preceding claims, characterized in that there is an annular gap (116) for a gas vortex (90.8), flowing from the mixing space (28) into the combustion space (12), in the annular wall (70.8), containing the gas passage opening (72), of the mixing chamber.
5. Apparatus according to Claim 4, characterized in that the annular wall is designed like a pipe or duct section (70.8) projecting into the combustion space (12).
6. Apparatus according to Claim 4 or 5, characterized in that the pipe or duct section (70.8) is designed to be cooled, such as, in particular, water-cooled.
7. Apparatus according to one of the preceding claims, characterized in that there is at least one central opening (62) in the baffle plate or in the heat shield (50.2).
8. Apparatus according to one of the preceding claims, characterized in that there is a feed line (18, 18.8) for feeding coarse dust and fine dust into the combustion space (12).
9. Apparatus according to Claim 8, characterized in that the feed line (18) for coarse dust and fine dust (16) opens into the mixing space (28) or into the region of the gas passage opening (72).
10. Apparatus according to Claim 9, characterized in that the feed line (18.8) for coarse dust and fine dust (120) opens into the combustion space (12).
11. Apparatus according to Claim 10, characterized in that the end region of the feed line (18.8) for the dust (120) is oriented with its outlet opening (118) approximately parallel to the wall of the pipe or duct section (70.8), so that the dust (120) flows out of the outlet opening (118) in a circular-cylinder wall oriented concentrically to the longitudinal axis (36) of the pipe or duct section (70.8).
12. Apparatus according to one of the preceding claims, characterized in that the blower (48) has at least one intake opening (42, 56) for fresh air.
13. Apparatus according to one of the preceding claims, characterized in that the blower (48) has at least one intake opening (42, 56) for recycled gas.
14. Apparatus according to one of the preceding claims, characterized in that the housing wall surrounding the annular space is also present as an outer boundary wall in the region of the mixing space (28) such that a construction component is present for generating the fire vortex (90).
15. Apparatus according to Claim 14, characterized in that the housing wall (26, 26.8, 78) extends up to the gas outlet opening (72).
16. Apparatus according to one of the preceding claims, characterized in that the annular wall (70, 70.7, 70.8) defining the gas passage opening (72) is designed as an external heat shield.
17. Apparatus according to one of the preceding claims, characterized in that the blower (48) has a blower wheel (32, 38, 40).
18. Apparatus according to Claim 17, characterized in that the blower wheel has a central shaft (32) and blade-like elements (38, 40) movably fastened to the shaft.
19. Apparatus according to Claim 18, characterized in that the blade-like elements have in each case mutually movable links (38, 40).

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