EP1359377A1 - Catalytic burner - Google Patents

Abstract

A radial swirl generator (6) is arranged between a radially outer inflow space (7) and a radially inner outflow space (8) leading axially to the combustion chamber (2). A fluid flows through one catalyst (5) before entering the combustion chamber.

Description

Technical field

The invention relates to a catalytic burner on or for one Combustion chamber, in particular a power plant, with the features of Preamble of claim 1.

State of the art

From JP 61 276 627 A a catalytic burner of this type is known a catalyst arranged in a ring and flowed through in burner operation and has a swirl generator through which the burner operates. It is the swirl generator is designed as an axial swirl generator in the axial direction is flowed through and the flow is subjected to a swirl. The axial swirl generator is concentric within the catalyst arranged so that the catalyst and swirl generator are flowed through in parallel.

Presentation of the invention

The present invention addresses the problem for one an improved catalytic burner of the type mentioned Specify embodiment, in particular the stability of the Combustion in the combustion chamber is increased.

This problem is solved by the subject of the independent Claim. Advantageous embodiments are the subject of the dependent Expectations.

The invention is based on the general idea for the application of Burner flow with a swirl using a radial swirl generator i.e. a swirl generator, which is flowed through radially and thereby an axial emerging swirl flow generated. With the same outlet cross section is at a radial swirl generator, the flow resistance is smaller than one axial swirl generator. Accordingly, in the case of the invention Burner a smaller pressure drop, which is of particular advantage here, as well Flow through the catalyst or catalysts always with a pressure drop accompanied.

Of particular advantage is an embodiment in which the swirl generator and the catalyst or catalysts are arranged in the same flow path, so that the entire flow through the catalytic converter (s) with the swirl is acted upon. This already leads to intensive mixing before entering the combustion chamber.

According to a preferred embodiment, the radial swirl generator have several rectilinear swirl generator channels, each opposite the Radial direction are inclined in the circumferential direction and a radially outer Connect the inflow space with a radially inner outflow space. This Construction has a relatively low flow resistance. The rectilinear swirl generator channels have one along their longitudinal direction constant cross-section, which makes it particularly easy constructed and therefore inexpensive catalysts in the swirl generator channels use. For example, conventional monolith catalysts can be used rectilinear and parallel catalyst channels or cells can be used. This makes it possible to use standard components, which is special is inexpensive. Instead of monolith catalysts, catalysts can also be used that are made of zigzag folded or undulating sheets multilayer folding, layering or wrapping can be produced.

It is particularly important that the catalysts in the radial Swirl generators are integrated, resulting in a particularly compact structure for gives the burner according to the invention.

Further features and advantages of the burner according to the invention result from the dependent claims, from the drawings and from the associated Description of the figures using the drawings.

Brief description of the drawings

Fig. 1

einen Längsschnitt durch eine stark vereinfachte Prinzipdarstellung eines erfindungsgemäßen Brenners,

Fig. 2

einen Querschnitt durch den Brenner gemäß Fig. 1 e ntsprechend den Schnittlinien II,

Fig.3

ein weiter vereinfachter Längsschnitt durch den Brenner bei einer anderen Ausführungsform,

Fig. 4

einen Querschnitt durch den Brenner gemäß Fig. 3 entsprechend den Schnittlinien IV,

Fig. 5 und 6

jeweils einen Längsschnitt wie in Fig. 3, jedoch bei anderen Ausführungsformen,

Fig. 7

einen Längsschnitt wie in Fig. 5, jedoch bei einer Weiterbildung,

Fig. 8

einen Querschnitt durch den Brenner gemäß Fig. 5 entsprechend den Schnittlinien VIII,

Fig. 9

einen Längsschnitt wie in Fig. 7, jedoch bei einer anderen Ausführungsform,

Fig.10

einen Querschnitt durch den Brenner gemäß Fig. 9 entsprechend den Schnittlinien X,

Fig.11 bis 14

vereinfachte Längsschnitte durch den Brenner bei unterschiedlichen Ausführungsformen.

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

Fig. 1

2 shows a longitudinal section through a greatly simplified schematic diagram of a burner according to the invention,

Fig. 2

2 shows a cross section through the burner according to FIG. 1, corresponding to section lines II,

Figure 3

another simplified longitudinal section through the burner in another embodiment,

Fig. 4

3 according to the section lines IV,

5 and 6

each a longitudinal section as in Fig. 3, but in other embodiments,

Fig. 7

5 shows a longitudinal section as in FIG. 5, but in a further development,

Fig. 8

5 according to the section lines VIII,

Fig. 9

7 shows a longitudinal section as in FIG. 7, but in another embodiment,

Figure 10

9 shows a cross section through the burner according to FIG. 9 according to the section lines X,

Fig. 11 to 14

simplified longitudinal sections through the burner in different embodiments.

1, a burner 1 according to the invention is connected to a combustion chamber 2 connected, in the combustion chamber 3 hot in the burner operation Combustion gases are generated at a preferred rate Application form of a gas turbine are fed to a power plant. The Burner 1 contains a catalyst arrangement 4 consisting of several Catalysts 5, which are flowed through in burner operation. Accordingly it is a catalytic burner 1. This burner 1 contains also a swirl generator 6, which is designed as a radial swirl generator, i.e. The swirl generator 6 is flowed through radially, here radially from the outside inside, giving the flow a twist. The radial swirl generator 6 is thereby between a radially outer inflow space 7 and a radial one outflow chamber 8 arranged inside. The swirl generator 6 and the Catalyst arrangement 4 are concentric with a longitudinal axis 9 of the Burner 1 arranged. The outflow chamber 8 leads in the axial direction, that is parallel to the longitudinal axis 9 to the combustion chamber 2 and thus connects the Downstream side of the swirl generator 6 with the combustion chamber 3.

A transition 10 between the outflow chamber 8 and the combustion chamber 3 has here a cross-sectional enlargement 11, which in particular has a jump-like design can be. This cross-sectional widening 11 allows the burner 1 generated swirl flow in the combustion chamber 3 quasi burst, whereby on the one hand In the area of the cross-sectional expansion 11, a first vortex system 12 is generated and, on the other hand, a central second swirl system 13 in the combustion chamber 3 is generated. With the help of the second swirl system 13 is in the combustion chamber 2 generates a central recirculation zone 14 which has a flame front 15 in the Combustion chamber 2 in the so-called "plenum", ie in the vicinity of burner 1 anchored and stabilized.

2, the radial swirl generator 6 has several Swirl generator channels 16, each in the same way opposite one of the central longitudinal axis 9 outgoing radial direction in the circumferential direction are inclined. This orientation of the swirl generator channels 16 results in the flow of the desired swirl. They are useful Swirl generator channels 16 tangential to an outlet cross section 17 aligned through which the gas flow from the outflow chamber 8 in the Combustion chamber 3 enters.

The swirl generator channels 16 are expediently rectilinear and with one in their Longitudinal direction constant cross section formed. This makes it possible Particularly simple catalysts 5 in the swirl generator channels 16 use. For example, the individual catalysts 5 consist of ceramic monoliths, which are coated in a suitable manner catalytically. It is also possible to use a stack or a catalyst 5 To build up winding of corrugated or zigzag folded sheet metal webs, the are also catalytically activated by a suitable coating. The Catalysts 5 each contain a large number of unspecified ones Catalyst channels, each parallel to and parallel to the Swirl generator channels 16 run. In order to overheat the catalysts 5 in To avoid burner operation, it may be appropriate to coat the individual catalyst channels so that not all catalyst channels, for example, only every second catalyst channel is catalytically active. With such a structure takes place in the catalytically inactive Catalyst channels no combustion reaction takes place, so that the carried in it Flow serves to cool the adjacent catalyst channels in which Combustion reactions take place. Such a catalyst structure is basically known from US 5,202,303 and therefore does not need to be specified are explained.

By inserting the individual catalysts 6 into the swirl generator channels 16 are the catalysts 5 and the catalyst arrangement 4 in the swirl generator 6 integrated. It is particularly important that with this structure the flow through the catalysts 5 simultaneously with the desired Swirl is applied.

Since the catalysts 5 are arranged in the radial swirl generator 6, they take place Positioning on a radius that is larger than the radius of the Outlet cross section 17. Accordingly, the flow for Catalysts 5 have a smaller pressure drop than in a comparable arrangement with a pure axial flow. The flow rate in the Catalyst channels and the pressure loss of the catalysts 5 can on the one hand over the length of the catalysts 5 and their cell density and by the axial extension of the catalysts 5 and the swirl generator channels 16 and thus the swirl generator 6 can be set. The interpretation is expedient of the burner 1 so that the burner operation at least in the outflow chamber 8 Flow velocity is greater than a turbulent Flame speed at which the flame front 15 faces the burner 1 want to spread. This measure can spread the Flame front 15 in the outflow chamber 8 can be avoided. Alternatively or In addition, the burner 1 is designed so that a Dwell time of the flow in the outflow chamber 8 is less than one Time delay until self-ignition in the outflow chamber 8 inflowing, partially reacted hot fuel-oxidizer mixture. By this measure can be the hot gas generation provided for the combustion chamber 3 be kept away from the outflow chamber 8. Wear the measures mentioned in each case that overheating of the catalysts 5 or Swirl generator 6 can be avoided.

According to FIGS. 3 and 4, the embodiment of the Burner 1 a primary injection device 18, the multiple injectors 19th has that to a common ring line 20 for fuel supply are connected. The ring line is via a fuel feed line 25 fueled. With the help of the injectors 19, the primary injection device conducts 18 upstream of the catalyst arrangement 4 in burner operation and thus upstream of the swirl generator 6 into the inflow space 7, in which the injectors 19 are arranged. 4 clearly shows that the primary injector 18 has one for each swirl generator channel 16 has a separate injector 19, the fuel directly into the respective Swirl generator channel 16 injected or injected. Adequate Mixing of the introduced fuel with the supplied gas flow can be achieved in each swirl generator channel 16 upstream of the catalysts 5 an inlet section 21 can be formed, which serves as a mixing space.

According to FIG. 3, a secondary injection device 22 is also provided, the for the introduction of fuel downstream of the catalyst assembly 4 in the Outflow chamber 8 is used. This secondary injection device 22 has one here central, ie coaxial to the longitudinal axis 9 aligned injector 23, the is expediently designed or aligned so that it is in the fuel substantially parallel to the longitudinal axis 9 in the direction of the combustion chamber 2 in the Abströmraum 8 injected or injected. The secondary injection device can likewise 22 have a plurality of injectors 23. Furthermore, it is clear that the injector (s) 23 of the secondary injector 22 also can be arranged eccentrically to the longitudinal axis 9. In particular, too lateral injection of the secondary fuel into the outflow space 8 be appropriate.

The secondary injection device 22 can be used to start the burner 1 or sufficient combustion for transient operating conditions Combustion chamber 2 can be realized. Such a "pilot operation" is, for example required if the catalysts 5 are not yet sufficiently high Have reached operating temperature. The discharge of secondary fuel can in addition to the transient operating states when the burner 1 is started up at partial load conditions may be beneficial to the reliability of the Increase burner operation.

In addition, it is basically possible to use the secondary injection device 22 initiate liquid fuel without this with the Catalysts 5 comes into contact. An additional aging of the catalysts 5 this can be avoided by adding liquid fuel.

While in the embodiment of FIGS. 3 and 4, the injectors 19 den Fuel virtually radially into the inflow space 7 or into the inlet sections 21 of the swirl generator channels 16 initiate, FIGS. 5 to 8 show embodiments in which the injectors 19 quasi axially the fuel into the inflow space 7 inject or inject. 5 and 7 show an almost only axial injection, while in Fig. 6 the fuel for Is injected inclined towards the longitudinal axis, so that the introduced fuel also receives a radial component. The injection is still carried out outside of the swirl generator channels 16, but in the Swirl generator channels 16 entering gas flow takes the fuel and in deflects the inlet sections 21.

7 and 8 is in the flow path between the Injectors 19 and the catalysts 5 each have a mixing device 24 arranged that an intensive mixing of the fuel with the Gas flow generated before this fuel-oxidizer mixture in the each catalyst 5 occurs. For this purpose, the mixing devices 24 arranged in the inlet sections 21 of the swirl generator channels 16. It is such a mixing device 24 for each catalyst 5 or each injector 19 assigned.

While in the embodiments shown so far in each Swirl generator channel 16 is arranged at least one catalyst 5, the Fig. 9 and 10 an embodiment in which in the circumferential direction only in every second Swirl generator channel 16 a catalyst 5 is arranged. Because of this design may also overheat the catalysts 5 or the swirl generator 6 be avoided. An embodiment is particularly expedient here has two primary injectors 18 and 18 ', the first primary injector 18 those swirl generator channels 16 with fuel supplied, in each of which one of the catalysts 5 is arranged. in the In contrast to this, the second primary injection device 18 'supplies the others Swirl generator channels 16, in which no catalyst 5 is arranged. The two Primary injection devices 18, 18 'each have a ring line 20 or 20' which, independently of one another, via fuel supply lines 25 or 25 ' be supplied with fuel. Since the two primary injectors 18, 18 'can be controlled independently of one another, it is possible to use the first Primary injector 18 the catalysts 5 a very lean fuel-oxidizer mixture to supply, whereby the heating of the catalysts 5 relative is easy to control. The remaining fuel used for the after-reaction in the Combustion chamber 2 is required, can then via the second primary injection device 18 'bypassing the catalysts 5 into the others Swirl generator channels 16 are initiated. Due to the swirl of the flow intensive mixing of the partial flows in the outflow chamber 8 before these enter the combustion chamber 2 together.

Although every second in the embodiment of FIGS. 9 and 10 Swirl generator channel 16 is equipped with a catalyst 5, can be used in a another embodiment also a different distribution of the catalysts 5 the swirl generator channels 16 are realized.

While the catalyst arrangement 4 in the previously shown Embodiments only one catalyst 5 per swirl generator channel 16 11 are 16 for each swirl generator channel in the embodiment according to FIG two catalysts 5a and 5b arranged one behind the other are provided. Between the successive catalysts 5a and 5b can have a mixing zone 26 be provided. The two catalysts 5a expediently differ and 5b for their catalytic activity. For example, the upstream arranged catalyst 5a have a higher activity to the Start the combustion reaction while the downstream catalyst 5b has a lower activity to overheat the catalyst 5b avoid.

In the embodiments of FIGS. 12 to 14, measures are exemplary shown, with the help of a wall 27 of the outflow chamber 8 against Overheating can be protected. This is conveniently done in the form of a active cooling and / or in the form of passive thermal protection. In the Embodiment according to FIG. 12 is a by blowing in cooling gas Film cooling 28 realized along the wall 27. In the variant according to FIG. 13 is the thermally loaded wall 27 with a heat protection layer 29 provided which the heat generated in the outflow chamber 8 from the wall 27 holds. In the embodiment according to FIG. 14, the wall 27 between the swirl generator 6 and the combustion chamber 2 with the aid of cooling 30 actively cooled. For example, the cooling takes place through the application the wall 27 with cooling gas.

LIST OF REFERENCE NUMBERS

1

burner

2

combustion chamber

3

combustion chamber

4

catalyst assembly

5

catalyst

6

swirl generator

7

inflow

8th

outflow

9

Longitudinal axis of 1

10

Transition between 8 and 2

11

Cross-sectional widening

12

first vortex system

13

second vertebral system

14

recirculation zone

15

flame front

16

Swirl generator duct

17

Outlet cross section of 8

18

Primary injector

19

injector

20

loop

21

Inlet section of 16

22

Secondary injector

23

injector

24

mixing device

25

Fuel supply line

26

mixing zone

27

Wall of 8

28

film cooling

29

Thermal protection layer

30

cooling

Claims (15)

Catalytic burner on or for a combustion chamber (2), in particular a power plant, with at least one catalyst (5) through which the burner is operated and with a swirl generator (6) through which the burner is operating,
characterized in that the swirl generator is designed as a radial swirl generator (6) which is arranged between a radially outer inflow space (7) and a radially inner outflow space (8) leading axially to the combustion chamber (2). Burner according to claim 1,
characterized in that the radial swirl generator (6) has a plurality of rectilinear swirl generator channels (16), each of which is inclined in the circumferential direction with respect to the radial direction and connects the inflow chamber (7) to the outflow chamber (8). Burner according to claim 2,
characterized in that at least one catalyst (5) is arranged in at least some of the swirl generator channels (16). Burner according to claim 2 or 3,
characterized in that at least some of the swirl generator channels (16) each have at least two catalysts (5a, 5b) which differ from one another, in particular with regard to the catalytic activity. Burner according to claim 3 or 4,
characterized in that the catalysts (5; 5a, 5b) arranged in the swirl generator channels (16) each have a multiplicity of catalyst channels running parallel to one another and to the associated swirl generator channel (16). Burner according to claim 5,
characterized in that at least with some catalysts (5) some of the catalyst channels are catalytically active, while the other catalyst channels are catalytically inactive. Burner according to one of claims 1 to 6,
characterized in that at least one primary injection device (18) is provided for introducing fuel into the inflow space (7) upstream of the catalyst (5) or the catalysts (5). Burner according to claims 2 and 7,
characterized in that the primary injection device (18) for each swirl generator channel (16) has at least one injector (19) for introducing fuel into the associated swirl generator channel (16). Burner according to claim 7 or 8,
characterized in that the primary injection device (18) for introducing fuel has a plurality of injectors (19), at least one mixing device (24) being arranged between the injectors (19) and the catalyst (5) or the catalysts (5). Burner according to claims 3 and 9,
characterized in that such a mixing device (24) is arranged in each swirl generator channel (16) in which at least one catalyst (5; 5a, 5b) is arranged. Burner according to Claim 2 and one of Claims 7 to 10,
characterized, that two mutually independent primary injection devices (18, 18 ') are provided, that only in some of the swirl generator channels (16) at least one catalyst (5) is arranged, while in the other swirl generator channels (16) no catalysts (5) are arranged, that one primary injection device (18) is used to introduce fuel into the swirl generator channels (16) equipped with the catalysts (5), while the other primary injection device (18 ') is used to introduce fuel into the other swirl generator channels (16) , Burner according to one of claims 1 to 11,
characterized in that a secondary injection device (22) is provided for introducing fuel downstream of the catalytic converter (5) or the catalytic converters (5) into the outflow chamber (8) and / or into the combustion chamber (2). Burner according to claim 12,
characterized in that the secondary injection device (22) is designed such that it introduces the fuel centrally in the direction of the combustion chamber (2) into the outflow chamber (8). Burner according to one of claims 1 to 13,
characterized in that a wall (27) of the outflow space (8) is cooled and / or thermally protected. Burner according to one of claims 1 to 14,
characterized in that the burner (1) is designed that in burner operation, at least in the outflow chamber (8), the flow velocity is greater than the turbulent flame velocity and / or that during burner operation the dwell time of the flow in the outflow chamber (8) is shorter than the time delay until the self-ignition of the partially reacted hot fuel-oxidizer mixture flowing into the outflow chamber (8).

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