EP1081434B1 - Device for generating a rotating gas flow - Google Patents

Description

The invention relates to a combustion plant according to the characteristics of Preamble of claim 1.

The flow channels are used to by means of the media of the composition of the Flow duct of the incinerator removed Flue gas mixture and its temperature and its To regulate residence time. However, composition, Temperature and residence time not only regulated but before everything be evened out. This way you can an optimal afterburning of the flue gas mixture ensures and can achieve the desired, low Emmisionswerte be respected. For this is one complete mixing of the flue gas mixture necessary. By generating rotating currents in the flow channel by means of devices with corresponding nozzle arrangements you try this to achieve complete mixing.

A generic combustion system is for example off US-A-5,252,298. The arranged in a plane Nozzles are tangential to one in the middle of the Flow channel imaginary circular line aligned, so that in the flow channel a rotating flow is generated. In one known from DE-A-19 648 639 incinerator is the flow rate through each other in the flow channel arranged opposite nozzles controlled so that at least two oppositely rotating currents in the Flow channel arise. The problem with these known rotating currents is that in the middle the flow creates an almost vertebrate free eye, so that no complete mixing and therefore no uniform composition, temperature distribution and Residence time is obtained.

Object of the present invention is therefore, a economic incineration plant to provide, with the complete mixing of flue gas mixtures obtained in the flow channel of the incinerator. This object is fulfilled by a combustion plant according to the features of claim 1.

Due to the special arrangement of first nozzles according to Claim 1 in a Eindüsebene in at least a first Wall section per wall, the at least a first Wall section of the opposite wall at an angle and the orientation of the first nozzles so in the injection level, that in the injection level lying angle between the wall and a dive Beam is at least approximately 90 °, becomes one generates a rotating flow in the flow channel and the others a very good mixing of the flue gas mixture reached. With diagonally opposite "is meant that the first wall sections for swirling the flowing material in the projection about in the direction of the jet flowing through the first nozzles is not or overlap only partially laterally. Especially at a distribution of first nozzles on first wall sections with a length 1 of 50% and more is ensured that rays of doused media to the center of the Pass flow channel. By the sum L of the lengths of the first wall sections of a wall of at least approximately 40% up to 80% of the total wall width b, i. E. by the first nozzles only over a portion of the Width b of the wall will extend material and Assembly costs for the nozzles saved, with efficiency the mixing is ensured.

In a special embodiment are in the Injection level in addition to the first nozzles in one second wall portion at an angle β to the first nozzles and diagonally against the center of the Flow channels aligned, provided second nozzles, which further improves the mixing.

Preferably, each wall several first and especially also prefers several second wall sections with first or second nozzles, so that vortex areas with counterrotating vortices are generated, causing the Blending even further improved.

It is particularly advantageous to use the second nozzles in one Angle α opposite to the injection plane with a Align Eindüskomponente downstream. In this case, each of the second nozzles with a Eindüskomponente a different angle α over the Have injection level or nozzles all the other nozzles with a Eindüskomponente in the same by the angle α plane tilted in relation to the injection plane Flow channel. That's how the rays are These nozzles are adjustable so that they are helical ineianderfliessen.

In a further preferred embodiment are on all four the flow channel limiting walls first Nozzles arranged in a first wall section. there the first wall sections are in the circumferential direction contrary to the rotating flow at the beginning of each Wall, leaving it from the first wall section of the wall adjacent wall are spaced and not each other touch. By this distribution of the first wall sections and its length of more than 0.5b can be a very good one generate rotating flow and by the injection of all four sides to the center of the flow channel optimal mixing of the flue gas mixture to reach.

It is particularly advantageous, the nozzles of all four walls to arrange in a level of injection. But the nozzles can also in two parallel directions of flow be arranged spaced injection levels, wherein each other opposite nozzles are arranged in a plane.

Ideally, they are point symmetrical opposite wall sections of equal length.

Advantageously, fresh secondary air and / or recirculated flue gas injected. When fresh Secondary air and recirculated flue gas are injected, are preferably provided annular gap nozzles. It exists the core jet of the annular gap nozzles from recirculated Flue gas and the ring stream of fresh secondary air.

Particularly advantageous is a control system, with its Help the throughput of the media to be atomized at least for opposite walls arranged nozzles is independently controllable.

If at least one injection level in the region of a Transition region between a combustion chamber and the Flue gas outlet located Flammdecke the incinerator arranged, so is to be atomized by the injection of Media in addition to the mixing and regulation of Flue gas mixture a very high cooling achieved thermal stress exposed blanket.

Further advantageous embodiments are the subject further dependent claims.

Fig. 1a, b

eine erste Ausführungsform der Erfindung mit an zwei einander gegenüberliegenden Wänden eines rechteckigen Strömungskanals angeordneten ersten Düsen und zweiten Düsen, wobei Fig. 1a den Schnitt längs des Strömungskanals und Fig. 1b einen Schnitt quer zum Strömungskanal zeigt;

Fig. 2a, b, c

eine zweite Ausführungsform der Erfindung mit einer Anordnung der Düsen analog derjenigen aus den Fig. 1a und 1b, wobei jedoch an den anderen zwei Wänden des rechteckigen Strömungskanals ebenfalls Düsen angeordnet sind und zwar in einer zweiten, zur ersten Eindüsebene in Strömungsrichtung beabstandeten, parallelen Eindüsebene und die Darstellung in Fig. 2a analog zu der aus Fig. 1a und die Darstellungen in den Fig. 2b und 2c analog derjenigen aus 1b sind.;

Fig. 3a, b

eine dritte Ausführungsform der Erfindung mit ersten Düsen an allen vier Wänden des rechteckigen Strömungskanals in einer Eindüsebene mit Darstellung analog den Fig. 1a und 1b;

Fig. 4a, b,

eine vierte Ausführungsform der Erfindung mit ersten Düsen an allen vier Wänden des rechteckigen Strömungskanals, wobei die Düsen in zwei voneinander in Strömungsrichtung beabstandete, parallelen Eindüsebenen verteilt sind und zwar jeweils einander gegenüberliegende erste Düsen in einer Eindüsebene und mit Darstellung analog den Fig. 1a und 1b;

Fig. 5

ein Beispiel für eine Ringspaltdüse;

Fig. 6

ein Steuerungssystem für die getrennte Steuerung der Durchsatzmenge für an verschiedenen Wänden angeordnete Düsen;

Fig. 7

eine weitere Ausführungsform der Erfindung zur Erzeugung von wenigstens zwei gegenläufig rotierenden Wirbeln.

The invention is explained in more detail below with reference to a few selected examples. FIGS. 1 to 6 show purely schematically:

Fig. 1a, b

a first embodiment of the invention with arranged on two opposite walls of a rectangular flow channel first nozzles and second nozzles, wherein Fig. 1a shows the section along the flow channel and Figure 1b shows a section transverse to the flow channel.

Fig. 2a, b, c

a second embodiment of the invention with an arrangement of the nozzle analogous to that of FIGS. 1a and 1b, however, are also arranged on the other two walls of the rectangular flow channel nozzles and that in a second, spaced from the first injection plane in the flow direction, parallel injection plane and the illustration in Fig. 2a analogous to that of Fig. 1a and the illustrations in Figs. 2b and 2c are analogous to those of Fig. 1b .;

Fig. 3a, b

a third embodiment of the invention with first nozzles on all four walls of the rectangular flow channel in a Eindropfenbene with representation analogous to Figures 1a and 1b.

Fig. 4a, b,

a fourth embodiment of the invention with first nozzles on all four walls of the rectangular flow channel, wherein the nozzles are distributed in two mutually spaced apart in the flow direction, parallel injection planes, namely each opposing first nozzles in a Eindropfenbene and with representation analogous to Figs. 1a and 1b ;

Fig. 5

an example of an annular gap nozzle;

Fig. 6

a control system for separately controlling the flow rate for nozzles arranged on different walls;

Fig. 7

a further embodiment of the invention for generating at least two counter-rotating vertebrae.

In Figs. 1a to 4a are of a waste incineration plant in each case a section of a flue gas outlet 10 as well a combustion chamber 12 and a transition region 20 between Combustion chamber 12 and flue 10 with a flame blanket 14 shown in section along the flue gas outlet 10. For the deduction of incineration Flue gas mixtures is a rectangular flow channel 18th provided, the transition area 20 of the Combustion chamber 12 to the flue gas outlet 10 and the flue gas outlet 10 includes. The principal flow direction of Flue gas mixture is indicated by an arrow 16. In FIGS. 1b to 4b, sections are respectively transverse to Flow channel 18 shown in the region of a feed plane 22, in which nozzles 24 for injecting verdüsbarer media are arranged. The nozzles 24 and their orientation are in all representations represented by arrows. The Müllflussrichtung is indicated by an arrow 9.

All the embodiments shown in FIGS. _{1 a to 4} b have first wall sections 28 with a length l ₁ of at least approximately two opposite walls 26 of at least approximately 40% to 80% of the wall width b of a wall 26. The first wall sections 28 are in each case point-symmetrical with respect to the central longitudinal axis 32 of the flow channel 18 as a geometric axis of symmetry and are bounded on one side by the adjacent wall 26. In the first, each point-symmetrically opposite wall portions 28 first nozzles 24a are arranged in a row 22 in a row. The first nozzles 24a are aligned in the injection plane 22, so that they inject into this, wherein the lying in the injection plane angle γ between injected jet 30 and wall 26 is about 90 °. This arrangement of nozzles 24 allows a good mixing of the excited in the flow channel 18 for rotation and flowing in the direction 16 flue gas mixture.

The injection level 22 is in all examples in the range the flame blanket 14, which in the transition region 20 between Flue gas outlet 10 and combustion chamber 12 is arranged. The Flammdecke 14 is penetrated either even by nozzles 24, as shown in all four examples, and / or it is via nozzles 24a ', 24b' ', which in walls (26) are arranged laterally below the flame blanket (14), with undermined media ", as shown in Figs. 2 to 4 is shown. In this way, the flame blanket 14 Cooled by the injected media.

1a and 1b, an embodiment is shown in which on two opposite walls 26 first wall portions 28 are provided with a length l ₁ of about 40% to 50% of the wall width b. In a second wall section 34 with length l ₂ , the row of the first nozzles 24a in the first wall section 28 are complementary, second nozzles 24b, which are aligned at an angle β with respect to the first nozzle 24a obliquely against the center of the flow channel 18 represented by the central longitudinal axis 32 are. The angle β is in this example about 25 °, but it can be between 20 ° and 50 °. The lengths l ₁ and l _{2 of} the two wall sections 28, 34 complement each other in this example to the entire wall width b, but this need not necessarily be so. Opposite the injection plane 22, the second nozzles 24b are aligned in a common plane 36, which is tilted by the angle α with respect to the injection plane 22. The angle α in this example is about 10 °, but may vary and be between 5 ° and 15 °. The second nozzles 24b are aligned such that the beams 30 generated by them flow into one another helically. Instead of a common plane 36, the second nozzles 24b may also be tilted at individual angles α with respect to the injection plane 22.

In Figs. 2a to 2c is an embodiment shown in the on all four walls 26 of the Flow channel 18 first nozzles 24a in a first Wall section 28 and second nozzles 24b in a second Wall section 34 analogous to that in Figs. 1a and 1b illustrated embodiment are arranged. The first Wall sections 28 are opposite in the circumferential direction the rotating flow respectively at the beginning of a wall 26th arranged. The nozzles 24a, 24b and 24a ', 24a' ', 24b', 24b '' are in two parallel, in the flow direction spaced-apart injection planes 22 and 22 * arranged, with nozzles 24 at opposite ends Walls 26 in a common injection plane 22, 22 * are arranged. The distance d between the injection planes 22, 22 * can be between 0.4m and 3m.

In the example shown in FIGS. 3a, 3b, first wall sections 28 with first nozzles 24a are arranged in a single injection plane 22 on all four walls 26 of the flow channel 18. The length l _{1 of} the first wall sections 28 is well above 0.5b, preferably at 0.55b to 0.75b. The remainder of each wall 26 remaining on the entire wall width b is free of nozzles 24. By this arrangement and orientation of the first nozzles 24a, it is possible to jet jets 30 into the center of the generated rotating flow so that complete mixing of the flue gas mixture takes place ,

Depending on the design of the flow channel 18 and the Design of the walls 26 may be necessary, be it for an optimization of the flow or because of the four Walls 26 are not in a single plane with nozzles 24a can be equipped, the nozzles 24a instead of in one single injection plane 22 (see Fig. 3a, 3b) in two to arrange parallel injection planes 22 and 22 *, as shown in Figs. 4a, 4b.

All nozzles are designed so that the media to be injected with can be injected at a pressure of 500Pa to 5000Pa.

In Fig. 5, an annular gap nozzle 24 * is shown as they For example, for injecting fresh secondary air and recirculated flue gas is provided. Shown is a first supply line 40 for the supply of a first Medium, in this case recirculated flue gas, in one formed as a core nozzle 42 and a core jet producing nozzle part and a second supply line 44 for the supply of a second medium, in this case fresh secondary air, in an annular gap 46th trained and producing a ring beam Nozzle part.

Via a control system 48, as shown in Fig. 6 for Ringspaltdüsen 24 * is shown, the different conditions, as on different Sides of the flow channel 18 can prevail, better Be taken into account. The throughputs of media to be injected are via the control system 48 and the valves 54 in the example shown with respect to the Garbage flow 9 upstream half 52 and the downstream half 50 of the flow channel 18th independently controllable. It would also be possible to have one separate control of the flow rates for the nozzles 24th on all four walls 26.

To regulate the temperature, the O ₂ content and to obtain the highest possible minimum residence time of the flowing through the flow channel flue gas mixture preferably nozzles 24 are provided for secondary air and nozzles 24 for recirculated flue gas. These nozzles 24 can be arranged either mixed in a row next to each other or in two rows one above the other, so that there is a separate injection level 22 for each nozzle 24. If annular gap nozzles 24 * are provided, then the core jet consists of flue gas and the ring jet of secondary air, as described for FIG. 5.

The embodiments shown here give the invention not conclusively again. This is possible, for example the device also in incinerators and To use waste incineration plants, in which the Transition region 20 between the combustion chamber 12 and Flue gas outlet 10 characterized by a constriction is. Also, more injection levels 22 deeper in the Combustion chamber 12 or higher in the flue gas outlet 10th be provided. Instead of or in addition to flue gas and Secondary air can also use other media such as water vapor Activated carbon, hearth furnace coke (HOK), waste z. B. in the context a residue recycling, fuels u.a.m. injected become. Also, to get a reducing atmosphere, the device can be used. In the same Direction of rotation as the first nozzles 24a can burner 2m to 3m above the injection plane 22 at two each other be arranged opposite walls 26.

FIG. 7 shows a further embodiment of the invention in which two counter-rotating vortices 60 ', 61' are produced. The device emerges from the device shown in Fig. 2b by reflection on the bottom wall 26, ie the first and second nozzles shown therein are doubled. The walls 26 of the device each have two first wall sections 28a1 and 28a2 or 28b1 and 28b2 with first nozzles 24a. The first nozzles 24a of the first wall sections 28a2, 28b2 in the lower half of the cross-section are arranged obliquely opposite each other and produce a clockwise-rotating first vortex 61 '. This is amplified by the second nozzles 24b of the second wall portions 34a2, 34b2. The second nozzles 24b radiate in a direction offset by +/- β with respect to the jet direction of the first nozzles. These second wall portions 34a2, 34b2 are also opposite each other obliquely. The wall regions in the lower half of the illustrated cross-section define a first vortex region 61. A second vortex region 60 is defined by the first and second wall sections 28a1, 28b1, 34a1, 34b1 in the upper part of FIG. The local second vortex 60 'rotates counterclockwise. The first wall sections 28a1, 28a2, 28b1, 28b2 each have a length l ₁ . Per wall 26 results in a total length L = l1 + l1 of about 0.5b. The obliquely opposite first wall sections 28a1 and 28b1 (second swirl 60 ') and 28a2 and 28b2 (second swirl 61') define the direction of rotation of the swirl 60 ', 61'. The second nozzles 24b then radiate to enhance the rotation, ie tangentially in the direction of rotation, to an imaginary circle about the center of the vortex 60 'and 61', respectively.

Claims (16)

1. An incineration plant, with a rectangular flow duct (18) which comprises a flue-gas outlet (10) of the incineration plant, in particular of a garbage incineration plant, with a plurality of nozzles (24) for injectable media, said nozzles being arranged in one injection plane (22) on two walls (26) of wall width b which lie opposite one another and delimit the flow duct (18), wherein the flow duct (18) comprises a transitional region (20) from a combustion chamber (12) of the incineration plant to the flue-gas outlet (10), and wherein in each case, in at least one first wall portion (28, 28a1, 28a2, 28b1, 28b2) of the two walls (26) lying opposite one another, first nozzles (24a) are aligned in a row in such a way that they inject into the injection plane (22) and the angle γ, lying in the injection plane (22), between the wall (26) and an injected jet (30) amounts to at least approximately 90°, the sum L of the lengths 1 of the first wall portions (28, 28a1, 28a2, 28b1, 28b2) amounting to at least approximately 0.4b < L < 0.8b, and the at least one first wall portion (28, 28a1, 28a2) of one wall lying obliquely opposite the at least one first wall portion (28, 28b1, 28b2) of the opposite wall, the wall portions not or only partially overlapping one another laterally in the projection approximately in the direction of the jet flowing into the first nozzles.
2. The incineration plant as claimed in claim 1, wherein the opposite walls have in each case a first wall portion (28), said wall portions lying point-symmetrically opposite one another, with the longitudinal center axis (32) of the flow duct (18) as the axis of symmetry, and being delimited on one side by the adjacent wall (26).
3. The incineration plant as claimed in claim 1 or 2, wherein second nozzles (24b) are arranged in each case in the injection plane (22) in at least one second wall portion (34, 34a1, 34a2, 34b1, 34b2) of the two opposite walls (26), |β|> 0°, preferably 20°<|β| < 50°, applying to the angle β, lying in the injection plane, between the jets injected by the first and the second nozzles (24, 24b), and preferably the at least one second wall portion (34, 34a1, 34a2, 34b1, 34b2) of one wall lying obliquely opposite the at least one second wall portion (34, 34a1, 34a2, 34b1, 34b2) of the opposite wall.
4. The incineration plant as claimed in claim 3, wherein, for generating a rotating vortex, each of the two opposite walls has a first (28) and a second (34) wall portion, and the first and the second wall portions lie in each case point-symmetrically opposite one another, with the longitudinal center axis (32) in the flow duct (18) as the axis of symmetry, and are delimited on one side by the adjacent wall (26').
5. The incineration plant as claimed in one of claims 1 to 3, wherein, for generating at least two contra-rotating vortices, each of the two opposite walls have at least two first wall portions (28, 28a1, 28a2, 28b1, 28b2).
6. The incineration plant as claimed in claim 5, wherein each of the two opposite walls have additionally two second wall portions, in each case a first (28a1, 28a2) and a second (34a1, 34a2) wall portion of one wall forming, with the directly opposite second (34b1, 34b2) or first (28b1, 28b2) wall portions of the opposite wall, a vortex region (60, 61), and the jets injected by the second nozzles (24b) being inclined at + |β| in a first vortex region (61) and at - |β| in a second vortex region (60) in relation to the jets injected by the first nozzles (24a).
7. The incineration plant as claimed in one of claims 3 to 6, wherein the second nozzles (24b) of the second wall portion (34) are aligned with an injection component at an angle α, which lies preferably between 5° and 15°, with respect to the injection plane (22) and preferably into a common plane (36) in the direction of flow in the flow duct (18).
8. The incineration plant as claimed in one of the preceding claims, wherein all four walls (26) of the flow duct (18) have a first wall portion (28) with first nozzles (24a), the first wall portions (28) being arranged in a circumferential direction, counter to the rotating flow, in each case at the start of a wall (26) and so as to be spaced apart from the first wall portion (28) of the adjacent wall (26).
9. The incineration plant as claimed in claim 8, wherein the nozzles (24) of all four walls (26) lie in the same injection plane (22).
10. The incineration plant as claimed in claim 8, wherein the nozzles (24) are arranged in two parallel injection planes (22, 22*) spaced apart from one another in the direction of flow, nozzles lying opposite one another lying in the same injection plane (22, 22*).
11. The incineration plant as claimed in either one of claims 5 and 6, wherein wall portions (28, 34) lying obliquely or point-symmetrically opposite one another have approximately the same length 1.
12. The incineration plant as claimed in one of the preceding claims, wherein the feed pressure at which the injectable media enter the nozzles is between 500Pa and 5000Pa, and wherein the throughput quantities for nozzles (24) arranged on different walls (26) can be controlled preferably independently of one another by means of a control system (48).
13. The incineration plant as claimed in one of the preceding claims, wherein the nozzles (24) provided are annular-gap nozzles (24*).
14. The incineration plant as claimed in one of the preceding claims, wherein nozzles (24) for the injection of secondary air and of recirculated flue gas are provided.
15. The incineration plant as claimed in claim 13, wherein the core jet of the annular-gap nozzles consists of recirculated flue gas and the annular jet consists of secondary air.
16. The incineration plant as claimed in one of the preceding claims, wherein at least one injection plane (22) lies in the region of a flame cover (14) arranged in the transitional region (20), so that nozzles (24, 38) pass through the flame cover (14) and/or the nozzles (24, 38) are arranged in walls (26) laterally below the flame cover (14), in such a way that they cool the flame cover (14) by injection.

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