EP1255077A2 - Device for the combustion of a gaseous mixture of fuel and oxidant - Google Patents

Abstract

An arrangement for burning a gaseous fuel-oxidant mixture, especially in power stations, comprises a catalyst turbulence producing unit (2) in which part of the fuel-oxidant mixture is burnt and in which a turbulent flow (6) is produced. The unit contains a catalyst and the channels are angled with respect to the longitudinal central axis.

Description

Technical field

The invention relates to a device for burning a gaseous fuel-oxidizer mixture, especially for a power plant.

State of the art

A premix burner is known from EP 0 833 105 A2, in which in an interior a conical inner body tapering in the direction of flow is arranged. An outer casing of the interior is tangential Arranged arranged air intervention channels through which a combustion air flow flows into the interior. This can cause a swirl flow in the interior form, which then with at least one fuel nozzle Fuel is enriched. The mixture is then formed in the downstream mixing tube of the two media. The mixing tube then goes over one Cross-sectional jump into a combustion chamber, taking place in the area of the plane of the cross-sectional jump forms a backflow zone, which the stability of the combustion guaranteed. To form such a mixing tube, the known premix burner a relatively large installation space. If you leave that Mixing tube away, reduces the stability and homogeneity of the flames in the Combustion chamber. There is also the risk of pressure pulsations.

Catalysts are known from US Pat. No. 5,202,303 and US Pat. No. 5,328,359 corrugated or folded sheet material are constructed, their folds or Waves form a multiplicity of flowable channels. With the flow such a catalyst becomes part of a fuel-oxidizer mixture burned. To avoid overheating with such a catalyst, the combustion must be limited to only part of the flow through the catalyst Mixture can be limited. For this purpose, only some of the channels, e.g. through an appropriate coating, catalytically active, while the other channels are catalytically inactive. When flowing through the catalyst then only finds combustion within the catalytically active channels instead of flowing through the catalytically inactive channels the catalyst cools. With conventional catalysts, however, the catalyst exit temperatures are too low to sufficiently stabilize the flames in the combustion chamber.

Presentation of the invention

The invention seeks to remedy this. The invention as set out in the claims is concerned with the problem for a device of the beginning mentioned type to specify an embodiment, in particular with regard Compactness of their structure and stability and homogeneity of the flames in the combustion chamber, is improved.

This problem is solved by the subject matter of the independent claims. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea of the fuel-oxidizer mixture to produce a swirl flow and the temperature of the mixture with a catalyst before entering the combustion chamber. To For this purpose, the device according to the invention has a flow-through catalyst swirl generator arrangement in which part of the fuel-oxidizer mixture burns and creates a swirl flow. By the invention Proposal can provide stability and homogeneity in the combustion chamber Flames increased and the risk of pulsation reduced. Furthermore, can such a catalyst swirl generator arrangement in the flow direction relative build short, so that the device has a compact overall structure.

In principle, it is possible to design the catalyst swirl generator arrangement in such a way that that they have a catalyst and a downstream immediately after Has swirl generator. However, an embodiment in which which the catalyst swirl generator arrangement has a catalyst which as Swirl generator is formed. In other words, the catalyst or the catalyst body is designed so that the flow emerging from it the desired Has swirl. This design allows two functions, namely the catalytic combustion and the swirl generation in a compact component to get integrated.

The catalyst swirl generator arrangement expediently has several, essentially flowable through parallel to one another, i.e. in the same direction Channels, some of which, especially about half, are catalytic active and the others are catalytically inactive. The channels can around a longitudinal central axis of the catalyst swirl generator arrangement is distributed be, with this longitudinal central axis in the main flow direction the catalyst swirl generator assembly extends. According to an advantageous one Embodiment, the channels can be inclined with respect to the longitudinal central axis be such that the longitudinal direction of the channels each opposite a straight line runs inclined, which extends parallel to the longitudinal central axis. hereby an arrangement is proposed for the channels, which causes that on the outflow side the catalyst swirl generator arrangement, i.e. at the outlet ends of the channels, the desired swirl flow emerges.

The pressure drop when flowing through the catalyst swirl generator arrangement can reduce the inclination of the channels relative to the longitudinal central axis in the direction of flow, in particular steady or step-like and continuous or progressively, increasing, with the inclination of the channels at the entrance can have the value zero, that is to say the channels then run at their entry parallel to the longitudinal central axis.

According to a special development, the catalyst swirl generator arrangement radial to the longitudinal central axis several layers of a corrugated or have folded first web material, the waves or folds of which are catalytic form active or inactive channels, being radial between two adjacent Layers an intermediate layer of a smooth second sheet material is arranged. This structure ensures that radially adjacent shafts or Wrinkles cannot penetrate into each other, so that the channels are always constant Have flow cross sections.

Further important features and advantages of the invention result from the subclaims, from the drawings and from the associated description of the figures based on the drawings.

Brief description of the drawings

Fig. 1

eine stark vereinfachte Prinzipdarstellung einer Vorrichtung nach der Erfindung,

Fig. 2

eine perspektivische Ansicht auf eine Katalysator-Drallerzeuger-Anordnung bei einer bevorzugten Ausführungsform,

Fig. 3

einen Teilquerschnitt durch die Katalysator-Drallerzeuger-Anordnung gemäß Fig. 2.

Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, the same reference symbols referring to the same or functionally identical or similar components. Each shows schematically

Fig. 1

a greatly simplified schematic diagram of a device according to the invention

Fig. 2

2 shows a perspective view of a catalyst swirl generator arrangement in a preferred embodiment,

Fig. 3

3 shows a partial cross section through the catalyst swirl generator arrangement according to FIG. 2.

Ways of Carrying Out the Invention

1, a device 1 according to the invention has a flow-through Catalyst swirl generator arrangement 2, whose upstream side 3 is a gaseous one Fuel-oxidizer mixture 4 is supplied, which in Fig. 1 by arrows is symbolized. The device 1 forms a burner with an inflow line 30, in which the catalyst swirl generator arrangement 2 is arranged. The invention Catalyst swirl generator arrangement 2 is designed so that in it part of the fuel-oxidizer mixture 4 burns and that on an outflow side 5 a swirl flow emerges, which is symbolized by an arrow 6. The catalyst swirl generator arrangement 2 is immediately before an abrupt one Cross-sectional expansion 7 (cross-sectional jump) arranged at the entrance a combustion chamber 8 is formed. This can cause the swirl flow to burst immediately.

With a sufficiently large number of swirls, a central recirculation zone 9 can thereby be formed in the combustion chamber 8. Corresponding vertebrae 10 are indicated by closed arrow lines. The recirculation zone 9 forms a kind of anchoring for a homogeneous flame front 11 in the combustion chamber 8. A stabilization of the flame front 11 results from the fact that the central vortex 10 mixes the products of homogeneous combustion in the combustion chamber 8 with the partially burned products of the catalytic Support combustion in the catalyst swirl generator arrangement 2. This corresponds to an internal exhaust gas recirculation, which intensively preheats the entire mixture and at the same time reduces the local speeds to values that correspond to the flame speed. This process is also supported in a corresponding manner by a recirculation zone 12 which is generated by the sudden cross-sectional widening 7. Corresponding vortices 13 are also indicated here by closed arrow lines. The flame stabilization achieved in this way additionally supports the complete combustion and reduces the emission of pollutants, such as CO and NO _x , due to the improved mixing.

Such a device comes e.g. for use in power plants and serves to generate hot gases for operating a turbine, in particular a gas turbine.

As already explained above, part of the fuel-oxidizer mixture burns 4 when flowing through the catalyst swirl generator arrangement 2, whereby the temperature of the introduced at the entry of the combustion chamber 8 Fuel-oxidizer mixture increased. These high temperatures also improve the flame stability and avoid the development of pulsations.

The exact position of the flame front 11 in the combustion chamber 8 can by Geometry and / or the arrangement and / or the structure of the catalyst swirl generator arrangement 2 are influenced.

The catalyst swirl generator arrangement 2 preferably consists of a catalyst 14, which is designed as a swirl generator. It is also possible to Swirl generator and the catalyst as separate components in the flow direction are arranged one behind the other. Such an embodiment is additionally indicated in Fig. 1 by a broken line which the Border 15 between an upstream catalyst 16 and a swirl generator 17 immediately downstream of the catalytic converter 16 symbolizes.

According to FIGS. 2 and 3, the catalyst swirl generator arrangement 2 a plurality of through-flow channels which run essentially parallel to one another 18 and 19 on. The one channels are designed as catalytically active channels 18, while the other channels are designed as catalytically inactive channels 19. Appropriately, catalytically active channels 18 and catalytically inactive alternate Channels 19 from, whereby the cooling effect for the catalyst 14 or the catalyst swirl generator arrangement 2 is improved. The channels 18, 19 are one Longitudinal central axis 20 of the cylindrical, in particular circular cylindrical, here Catalyst swirl generator arrangement 2 in the radial direction and in the circumferential direction distributed. The longitudinal central axis 20 runs parallel to the main flow direction of the catalyst swirl generator arrangement 2.

In order to integrate the swirl generator into the catalytic converter 14, the channels 18, 19 inclined with respect to the longitudinal central axis 20, that is, the longitudinal directions of the Channels 18, 19 are each inclined to a straight line that is parallel to Longitudinal central axis 20 runs. This relationship is exemplary in FIG. 2 shown on a single channel 18, i.e. one with a broken line shown longitudinal direction 21 of this channel 18 is opposite by an angle α a line 22 also represented by a broken line, which extends parallel to the longitudinal central axis 20.

This angle of inclination α must be chosen large enough to ensure that the central recirculation zone 9 can form in the combustion chamber 8. In addition, the angle of inclination α may not be chosen too large to avoid a too large pressure drop at the cross-sectional expansion 7. At least in the case of channels 18, 19 arranged radially further out, there are suitable ones Values for the angle α, for example between 30 ° and 60 °, which e.g. swirl numbers Ω can correspond from 0.4 to 1.2. If the outflow side 5 of the catalyst swirl generator arrangement 2 positioned immediately in front of the cross-sectional expansion 7 is, the angle of inclination α and thus the pressure loss of the arrangement 2 can be reduced.

In the embodiment according to FIG. 2, all channels 18, 19 have along them entire length the same inclination α with respect to the longitudinal central axis 20. At In another embodiment, not shown here, the inclination α of the channels 18, 19 with respect to the longitudinal central axis 20 in the flow direction the catalyst swirl generator arrangement 2 increase. This change in slope can be done steadily and progressively. In particular, the inclination α on the upstream side of the catalyst swirl generator arrangement 2 the value have α = 0 °. Through this design of the channels 18, 19, the flow resistance the catalyst swirl generator arrangement 2 can be optimized. At a other embodiment, the inclination α of the channels 18, 19 radially from the inside increase outwards. This means that with channels 18, 19, the radially further inside are arranged, the inclination α can be smaller than in channels 18, 19, the are arranged radially further outside. These measures simplify production the catalyst swirl generator arrangement 2.

For example, the catalyst swirl generator arrangement 2 can be on the upstream side 3 containing first longitudinal section 23 and a the outflow side 5 have second longitudinal section 24. These longitudinal sections 23, 24 are indicated in Figure 2 by curly brackets. The longitudinal cuts 23, 24 can - as here - be about the same size. In a preferred embodiment can the channels 18 and 19 in the first longitudinal section 23 parallel to Longitudinal central axis 20 extend while they are in the second longitudinal section 24 Have inclination with respect to the longitudinal central axis 20, optionally in the flow direction can increase. As a result, the swirl generator 17 is in the rear longitudinal section 24 of the arrangement 2 is formed. The second expediently extends Longitudinal section 24 over about a fifth, a quarter or a third of the total length arrangement 2.

According to FIGS. 2 and 3, the catalyst swirl generator arrangement 2 expediently be constructed in that a corrugated or folded first Web material 25 placed on a flat or smooth second web material 26 becomes. With respect to the longitudinal central axis 20, this forms in the radial direction a stratification, the ones formed by the first sheet material 25 Layers are separated radially from each other by intermediate layers second sheet material 26 are formed. With this construction, the second ensures Web material 26 that the waves and folds of the first web material 25 of the one layer not in the waves and folds of the first sheet material 25 one radially neighboring layer can protrude. Rather, the intermediate layers ensure from the second sheet material 26 constant channel cross sections. The individual channels 18 and 19 are the waves or folds of the first web material 25 is formed. To train the catalytically active Channels 18 can expediently have one side of the first web material 25, as shown in FIG. 3 each the top, coated with a catalytically active coating 27 his. The opposite underside of the first web material 25 is then uncoated, whereby the catalytically inactive channels 19 arise. alternative or in addition, the layers of the second web material 26 can also be one-sided be coated with the catalyst coating 27 to the catalytically active Form channels 18. The web materials 25, 26 expediently consist of a Metal sheet that is preformed and coated if necessary is.

The web materials 25 and 26 can be concentric with respect to the longitudinal central axis 20 be layered. However, an embodiment is preferred in which the sheet materials 25 and 26 are spirally layered with respect to the longitudinal central axis 20 are. This results in a particularly simple way of Herteln the catalyst swirl generator arrangement 2:

The stacked web materials 25 and 26 are placed on a spindle 28 wound up after winding up the center of the catalyst swirl assembly 2 forms and extends concentrically to the longitudinal central axis 20.

The spindle 28 thus carries the web material 25, 26, its diameter so is chosen large that the winding of the corrugated or folded first web material 25 is still feasible with reasonable effort. The complete winding can be secured, for example, by tension wires 29, which are circumferential include the winding and this at least until the catalyst swirl generator arrangement is installed 2 keep in shape in a burner or the like.

This spindle 28 is expediently designed in such a way that, with its help, the central one Recirculation zone 9 or the flame front 11 in the combustion chamber 8 (see FIG. 1) can be influenced in particular with regard to shape and position. For example the spindle 28 is designed as a flow-through tube, which is a central Flow through the catalyst swirl generator arrangement 2 with the fuel-oxidizer mixture 4 enables. The tubular one can then expediently be formed Spindle 28 has an outlet nozzle or an outlet orifice at its outlet end have, and it may also be appropriate, the exit end form that it converges in the direction of flow. Through these measures can aerodynamic quantities of the flow entering the combustion chamber 8 be changed, depending on the position and extent of the flame front 11 and / or the central recirculation zone 9.

It is also possible to insert a lance for a fuel and / or into the spindle 28 Integrate oxidizer injection.

In order to be able to generate the desired swirl, the swirl generator is required Structure a minimum length L, which results from the fact that the channel diameter divided by the tangent of the angle of inclination α. The hereby determined Length is relatively short, so that the construction explained above with reference to FIG separate catalyst 16 and separate swirl generator 17 in the direction of flow builds relatively short. With the integrated design, the axial length of the designed as a swirl generator 14, ie the catalyst swirl generator arrangement 2, according to the requirements of the catalytic conversion of the system judge.

The integrated design of the catalyst swirl generator arrangement 2 is also then of particular advantage if the arrangement 2, as explained above with reference to FIG. 1, has two or more longitudinal sections 23, 24, in which the channels 18, 19 differ from each other in terms of their inclination. For example the channels 18, 19 in the upstream first longitudinal section 23 opposite the The longitudinal central axis 20 is not inclined, so that it is parallel to the main flow direction extend while being inclined in the downstream longitudinal section 24 are and so train the swirl generator. The one-piece construction of the catalyst swirl generator arrangement 2 reduces pressure losses in the transition between the successive longitudinal sections 23, 24. While one Construction with separate longitudinal sections 23, 24 for the transition from one Longitudinal section 23 to the other longitudinal section 24 to achieve a sufficient Mix a minimum distance between the successive Longitudinal sections 23, 24 must be observed, is omitted in the one-piece Formation of the longitudinal sections 23, 24 such a transition and mixing area, so that the arrangement 2 according to the invention can build particularly short.

A significant advantage of the catalyst swirl generator arrangement presented here 2 is seen in the fact that in the arrangement 2 according to the invention the ignition a homogeneous combustion reaction within the channels 18 avoided can be reduced, which also reduces the risk of flashbacks is. In order to achieve this goal, the channels 18 can be sufficient small flow cross-sections, for example between 1 mm and 5 mm can be equipped. This has the consequence that very large Form surfaces, which counteracts flame formation (thermodynamic Flame extinction). This allows the along the length of the channels 18 homogeneous ignition can be avoided. On the other hand, one supports catalytically active surface within the swirl generator the adsorption of radicals homogeneous phase, thereby avoiding ignition and a flashback (chemical flame extinguishing).

LIST OF REFERENCE NUMBERS

1

contraption

2

Catalyst swirl-generator arrangement

3

Upstream side of 2

4

Fuel-oxidizer mixture

5

Downstream side of 2

6

swirl flow

7

Cross-sectional widening

8th

combustion chamber

9

central recirculation zone

10

whirl

11

flame front

12

recirculation zone

13

whirl

14

catalyst

15

border

16

catalyst

17

swirl generator

18

catalytically active channel

19

catalytically inactive channel

20

Longitudinal central axis of 2

21

Longitudinal direction of 18, 19

22

Just

23

first longitudinal section

24

second longitudinal section

25

first web material

26

second web material

27

catalytic coating

28

spindle

29

tension wire

30

inflow

Claims (21)

Device for burning a gaseous fuel-oxidizer mixture, especially for a power plant, with a flow-through catalyst swirl generator arrangement (2) in which part of the fuel-oxidizer mixture burns and generates a swirl flow (6). Apparatus according to claim 1, characterized in that the catalyst swirl generator arrangement (2) has a catalyst (16) and a swirl generator (17) immediately downstream of it. Apparatus according to claim 1, characterized in that the catalyst swirl generator arrangement (2) has a catalyst (14) which is designed as a swirl generator. Device according to one of claims 1 to 3, characterized in that the catalyst swirl generator arrangement (2) is arranged immediately upstream of an abrupt cross-sectional expansion (7) at the inlet of a combustion chamber (8). Device according to one of claims 1 to 4, characterized in that the catalyst swirl generator arrangement (2) has a plurality of flowable channels (18, 19), one of which is catalytically active and the other catalytically inactive. Apparatus according to claim 5, characterized in that the channels (18, 19) are distributed around a longitudinal central axis (20) of the catalyst swirl generator arrangement (2) which extends in the main flow direction of the catalyst swirl generator arrangement (2) , and that the channels (18, 19) are inclined with respect to the longitudinal central axis (20) of the catalyst swirl generator arrangement (2) such that the longitudinal directions (21) of the channels (18, 19) are each opposite a straight line (22) run inclined, which runs parallel to the longitudinal central axis (20) of the catalyst swirl generator arrangement. Apparatus according to claim 6, characterized in that the inclination of the channels (18, 19) with respect to the longitudinal central axis (20) of the catalyst swirl generator arrangement (2) increases in the direction of flow. Apparatus according to claim 6 or 7, characterized in that the inclination of the channels (18, 19) with respect to the longitudinal central axis (20) of the catalyst swirl generator arrangement (2) increases radially from the inside to the outside. Device according to one of claims 6 to 8, characterized in that the channels (18, 19) in a first longitudinal section (23) containing the inflow side (3) of the catalyst swirl generator arrangement (2) parallel to the longitudinal central axis (20) of the catalyst Swirl generator arrangement (2) and are only inclined in a second longitudinal section (24) containing the outflow side (5) of the catalyst swirl generator arrangement (2) with respect to the central longitudinal axis (20) of the catalyst swirl generator arrangement (2). Device according to one of claims 5 to 9, characterized in that the catalyst swirl generator arrangement (2) radially to a longitudinal central axis (20) running parallel to the main flow direction of the catalyst swirl generator arrangement (2) has a plurality of layers of a corrugated or folded first Has web material (25), the waves or folds of which form the channels (18, 19), an intermediate layer of a flat or smooth second web material (26) being arranged radially between two adjacent layers. Device according to claim 10, characterized in that the web materials (25, 26) are layered concentrically or spirally with respect to the longitudinal central axis (20). Apparatus according to claim 10 or 11, characterized in that the catalyst swirl generator arrangement (2) has a central spindle (28) which extends concentrically to the longitudinal central axis and which carries the web materials (25, 26). Apparatus according to claim 12, characterized in that the spindle (28) is designed such that it has a recirculation zone (9) and / or a flame front (11) in a combustion chamber (8) arranged downstream of the catalyst swirl generator arrangement (2). aerodynamically influenced. Apparatus according to claim 12 or 13, characterized in that the spindle (28) is designed as a flow-through tube through which part of the fuel-oxidizer mixture flows centrally through the catalyst swirl generator arrangement (2). Device according to claim 14, characterized in that the tubular spindle (28) converges at its outlet end and / or has an outlet orifice and / or an outlet nozzle. Catalyst swirl generator arrangement for a device (1) for combustion a fuel-oxidizer mixture, in particular for a power plant, wherein the catalyst swirl generator arrangement (2) is designed so that it can flow through the fuel-oxidizer mixture and that the fuel-oxidizer mixture when flowing through the catalyst swirl generator arrangement (2) is subjected to a swirl and partially burns. Catalyst swirl generator arrangement according to claim 16, characterized by the characterizing features of at least one of claims 2 to 15. Method for producing a catalyst swirl generator arrangement (2) according to Claim 16 or 17 for a device (1) according to one of claims 1 to 15, in the case of a corrugated or folded first web material (25) smooth or flat second sheet material (26) is placed and in which the superimposed web materials (25, 26) wound on a spindle (28) become. A method according to claim 18, characterized in that the waves or folds are inclined with respect to the longitudinal axis of the spindle. A method according to claim 18 or 19, characterized in that the waves or folds which follow one another in the winding direction are alternately catalytically active and catalytically inactive. Method for burning a fuel-oxidizer mixture, in particular for a power plant, in which the fuel-oxidizer mixture with is subjected to a swirl and is partially catalytically burned before it enters a combustion chamber is initiated.

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