EP1781988A1

EP1781988A1 - Hybrid burner lance

Info

Publication number: EP1781988A1
Application number: EP05775906A
Authority: EP
Inventors: Andreas Dr. Brautsch; Daniel Burri; Hanspeter Hardegger; Bettina Dr. Paikert
Original assignee: Alstom Technology AG
Current assignee: General Electric Technology GmbH
Priority date: 2004-08-23
Filing date: 2005-08-18
Publication date: 2007-05-09
Anticipated expiration: 2025-08-18
Also published as: TW200617323A; WO2006021541A1; US20070207425A1; DE102004041272A1; US7963764B2; MX2007001887A; EP1781988B1; DE102004041272B4; TWI366648B; CA2577770A1; ES2556165T3; CA2577770C

Abstract

The invention relates to a lance (3) for a hybrid burner (2) of a combustion chamber (1) of a gas turbine. Said lance comprises: - an interior duct (10) for a liquid fuel; - an exterior duct (11) for a gaseous fuel, which coaxially surrounds the interior duct (10); - several outer nozzles (12) that are disposed in a stellar manner and extend radially from the exterior duct (11); - several inner nozzles (14) which extend radially from the interior duct (10) and run coaxially within one of the outer nozzles (12). respectively; - and a distribution section (18) that is located upstream of the outer nozzles (12) in the exterior duct (11) and is provided with several stellarly arranged, coaxially extending passages (19) for the gaseous fuel. In order to reduce the resistance to fluid flow in the gas path of the lance (3), the passages (19) are wider in the circumferential direction than they are in the radial direction.

Description

Hybrid burner lance

Technical area

The invention relates to a lance for a hybrid burner of a combustion chamber of a gas turbine, in particular a gas turbine for a power plant.

State of the art

With the aid of such a lance, a liquid fuel, for example a suitable oil, and a gaseous fuel, for example natural gas, can be injected alternatively or cumulatively into a hybrid burner. The supply of the lance with the gaseous fuel usually takes place via a pipeline in which a gas pressure predetermined by the gas supply system prevails. In a variety of applications, e.g. in a combustion chamber with low-pressure burner and downstream high-pressure burner, however, this existing system pressure in the pipeline is too low to the gaseous

To inject fuel with sufficient pressure difference through the lance into the combustion chamber. Accordingly, it is common to place an additional compressor upstream of the lance to raise the gaseous fuel to the required pressure level. The installation of such an additional Compressor, however, increases the installation costs of the combustion chamber or the gas turbine equipped therewith. In addition, the additional compressor for its operation requires energy, which reduces the efficiency of the power plant in a preferred application of the gas turbine in a power plant for power generation.

Presentation of the invention

The invention aims to remedy this situation. The invention, as characterized in the claims, deals with the problem of providing a lance of the type mentioned an improved embodiment, which in particular allows operation of the hybrid burner equipped therewith at a comparatively low pressure in the gaseous fuel.

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

The invention is based on the general idea of reducing aerodynamic improvements in the gas path of the lance whose flow resistance, thereby reducing the pressure drop occurring in the flow through the lance. As a result, it can lower the pressure required in the gaseous fuel upstream of the lance. The aim is to lower the flow resistance in the gas path of the lance as far as possible so that the remaining pressure drop allows proper operation of the burner already at the prevailing system pressure in the pipeline. This means that it is then possible to dispense with an additional compressor upstream of the lance. In the case of the invention, the flow resistance in the gas path of the lance is significantly reduced in particular because, in the case of a distributor section which is arranged upstream of the outer nozzles in the outer channel and which has a plurality of star-shaped, axially extending passage openings for the gaseous fuel, the passage openings are dimensioned in that these each have a larger opening width in the circumferential direction than in the radial direction. By this construction, the flow-through cross-section in the manifold section is considerably increased, which reduces its flow resistance accordingly. In this case, the invention utilizes the knowledge that, as the distributor section flows through within the lance, a particularly serious pressure drop occurs, so that there is a particularly great potential for reducing the flow resistance.

According to an advantageous embodiment, the outer channel may be limited axially in the region of the outer nozzles by an outer end wall, whereby the outer channel is axially closed. In the case of each outer nozzle, an axial recess is then formed in the outer end wall on a side remote from the distributor section. With the help of such a depression, the inner nozzles extending coaxially within the outer nozzles can flow much better, which considerably simplifies the flow of the gaseous fuel from the outer tube into the outer nozzles, in particular at their side remote from the distributor section. Accordingly, in the area of the transition between the outer tube and the outer nozzles of the

Flow resistance significantly reduced. At the same time, in such an embodiment, the homogeneity of the flow through the outer nozzles and thus the quality of the injection of the gaseous fuel can be improved. A further reduction of the pressure drop in the gas path of the lance can be realized in another embodiment in that with each outer nozzle, a transition from the outer channel to an outer nozzle channel formed in the interior of the respective outer nozzle is provided with an inlet zone tapering in the direction of flow. Such an inlet zone reduces the flow resistance during the deflection of the gas flow, which also reduces the total resistance of the lance.

Further important features and advantages of the lance according to the invention will become apparent from the subclaims, from the drawings and from the associated description of the figures with reference to the drawings.

Brief description of the drawings

Preferred embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components. Show, in each case schematically,

Fig. 1 is a simplified schematic representation of a lance according to the invention in

2, a perspective, partially sectioned view of a head of the

Lance, Fig. 3 is a partially sectioned, perspective view of the lance head of FIG. 2 corresponding to a marked in Fig. 2 with IM other viewing direction, Fig. 4 is a half longitudinal section of the lance head in a nozzle region. According to FIG. 1, a combustion chamber 1, which is only partially indicated here, comprises at least one hybrid burner 2, which is equipped with a lance 3. The combustion chamber 1 is preferably a component of a gas turbine, not shown here, in particular for generating electricity within a power plant.

The hybrid burner 2 may burn both gaseous fuels, such as natural gas, and liquid fuels, such as a suitable oil. Accordingly, the lance 3 is connected on the one hand to a liquid fuel supply line 4 and on the other hand to a gas fuel supply line 5. In the

Liquid fuel supply line 4 is usually arranged a pump 6 in order to be able to supply the liquid fuel with the required supply pressure. In contrast, the gas fuel supply line 5 is connected substantially directly to a pipeline, not shown here, which provides the gaseous fuel at a comparatively low pipeline pressure. Due to the inventive design of the lance 3, it is possible to dispense with a compressor in the gas fuel supply line 5 upstream of the lance 3.

The burner 2 compressed air is supplied according to an arrow 7 from a compressor, not shown. The lance 3 is introduced with respect to the flow direction of the air 7 substantially radially to the burner 2 and has a projecting into the burner 2, substantially rectangular angled lance head 8. The lance head 8 is thus with respect to its longitudinal central axis 9 parallel to the main flow direction of the supplied air. 7 oriented. The lance head 8 is configured such that it injects the liquid and / or gaseous fuel radially into the burner 2 with respect to its longitudinal central axis 9, that is, with respect to the main flow direction of the air 7 prevailing in the burner 2. The following explanations relate in particular to the lance head 8.

According to FIGS. 2 and 3, the lance 3 contains in its head 8 an internal duct 10 for liquid fuel and an external duct 11 for gaseous fuel. The two channels 10, 11 are arranged coaxially with each other, so that the outer channel 11 surrounds the inner channel 10. Accordingly, the outer channel 11 has an annular cross section, while the inner channel 10 has a full cross section. Inner channel 10 and outer channel 11 are separated by an inner tube 16 and enclosed by a coaxially arranged outer tube 17.

For injection of the gaseous fuel, the lance 3 is equipped at its head 8 with a plurality of outer nozzles 12, which are arranged in a star shape with respect to the longitudinal central axis 9 and extend radially from the outer channel 11. The outer nozzles 12 each contain an outer nozzle channel 13 which extends radially from the outer channel 11 and communicates with this. Accordingly, the gaseous fuel can be injected into the burner 2 via the outer nozzles 12.

In a corresponding manner, the lance 3 is also equipped at its head 8 with internal nozzles 14, which are also arranged in a star shape with respect to the longitudinal central axis 9 and thereby depart radially from the inner channel 10. In each case, an inner nozzle 14 is arranged coaxially within an outer nozzle 12, wherein inner nozzles 14 and outer nozzles 12 radially outwardly each ends approximately flush. Each inner nozzle 14 includes an inner nozzle channel 15 which communicates with the inner channel 10. Accordingly, the liquid fuel can be injected into the burner 2 via the inner nozzles 15. The coaxial arrangement of the nozzles 12, 14 results in an annular cross section for the outer nozzle channel 13, while the inner nozzle channel 15 has a full cross section.

In the outer channel 11, a distributor section 18 is arranged upstream of the outer nozzles 12, which is characterized in Fig. 2 by a curly bracket. The distributor section 18 forms an annularly closed axial section of the lance 3 or of the lance head 8 and may in particular be formed in one piece on the outer tube 17. The distributor section 18 is thus arranged in the flow-through cross section of the outer channel 11. However, in order for the gaseous fuel to be able to reach the outer nozzles 12, the distributor section 18 is provided with a plurality of star-shaped passage openings 19 which extend axially through the distributor section 18. Such a distributor section 18 is required in order to avoid a damage event in which the lance head 8 z. B. has become leaky due to overheating, to ensure a certain pressure difference to the gas path, so that the flame front can not migrate into the gas path against the gas flow direction and thus not too much fuel can flow uncontrollably into the burner 2.

In order for the gaseous fuel distributor section 18 to have as low a flow resistance as possible, the passage openings 19 are each designed such that they have a larger opening width in the circumferential direction than in the radial direction. In FIG. 3, the circumferential opening width oriented in the circumferential direction is marked by an arrow 20, while those in FIG

Radially oriented radial opening width is indicated by an arrow 21. It can be clearly seen that the circumferential opening width 20 is more than twice as large as the radial opening width 21. In particular, the circumferential opening width 20 is approximately three to five times larger, preferably approximately four times larger than the radial opening 21. By the selected dimensioning of the through holes 19, this results in a comparatively low flow resistance, so that the occurring during the flow through the manifold section 18 pressure drop is correspondingly low. As a result, a comparatively low flow resistance also results for the lance 3.

In the preferred embodiment shown here, the passage openings 19 extend in the circumferential direction in each case along a circular arc segment, as a result of which a particularly large flow-through cross section for the respective passage openings 19 can be achieved. In principle, other cross-sectional geometries may also be used, for example elliptical cross sections.

Without limitation of generality are shown here

Embodiment four through holes 19 are provided. The individual passage openings 19 are separated from one another in the circumferential direction by webs 22. The webs 22 extend radially and axially with respect to the longitudinal central axis 9. Compared to the through holes 19, these webs 22 have only a comparatively small cross section. Preferably, the circumferential opening width 20 of the through openings 19 is at least three times greater than a wall thickness 23 of the webs 22 measured in the circumferential direction. In particular, the webs 22 are dimensioned such that the circumferential opening width 20 of the through openings 19 is approximately four to eight times greater than the wall thickness 23 Footbridges 22.

Referring to FIG. 4, it can be seen particularly clearly that the outer channel 11 is axially closed by an outer end wall 24 in the area of the outer nozzles 12. Since the outer nozzles 12 and the outer nozzle channels 13th With respect to the outer channel 11 are radially oriented, it comes at a transition 25 between outer channel 11 and outer nozzle channel 13 to a relatively strong flow deflection, which is shown in Fig. 4 by arrows. In order to reduce the pressure drop associated with the flow deflection, an axial recess 26 can be recessed in the outer end wall 24 in each outer nozzle 12 at a side facing away from the distributor section 18, according to an advantageous embodiment. This depression 26 makes it easier for the gas flow in the inner channel 11 to flow around the respective inner nozzle 14. As a result, the deflection of the gas flow at the side facing away from the distributor section 18 side with the outer nozzle 12 can be improved. This leads to an equalization of the pressure distribution within the transition 25, with the result that on the one hand the flow resistance in the region of the transition

On the other hand, the homogeneity of the flow distribution within the outer nozzle channel 13 is improved.

The depressions 26 can-as shown here in FIG. 4-be provided separately for each outer nozzle 12, in which case an embodiment is preferred in which the depression 26 is configured as a circular arc segment with respect to a longitudinal central axis 27 of the nozzles 12, 14. As a result, so-called "dead water areas" can be reduced and the flow resistance can be lowered Alternatively, it is basically also possible to provide a common depression 26 for all external nozzles 12. Such a common depression

26 then forms in the outer end wall 24 a circumferentially closed circumferential annular groove. Such an embodiment can be produced particularly easily.

Particularly favorable values for the pressure drop at the transition 25 can be achieved if the dimensioning of the recess 26 is matched to the dimension of the outer nozzle channel 13 in a special way. Cheap is For example, an embodiment in which a relative to the longitudinal central axis 27 of the outer nozzle 12 measured radial depth 28 is about twice or at least twice greater than a radial distance 29 between an unspecified inner wall of the outer nozzle 12 and an unspecified outer wall of the inner nozzle 14 arranged therein ,

Another measure for reducing the pressure loss within the lance 3 is seen in an aerodynamic optimization of the transition 25. For this purpose, the transition 25 shown in FIG. 4 may be equipped with an inlet zone 30, which tapers in the flow direction. As a result, the flow resistance during the transition from the outer channel 11 is reduced in the respective outer nozzle channel 13. The taper of the inlet zone 30 can be achieved by a simple chamfering. It is also possible to design the rejuvenation rounded.

As can be seen in FIGS. 2 to 4, a divider 31 is expediently arranged in the inner channel 10 in the region of the inner nozzles 14. The divider 31 includes a core 32 that extends concentrically within the inner channel 10. At this core 32 dividing walls 33 are formed, which extend radially and axially and protrude from the core 32 in a star shape, such that they

Touch inner tube 16. Advantageously, the core 32 and the partitions 33 are designed swept in the direction of flow to the longitudinal central axis 9 back. With the help of such a divider 31, the deflection of the liquid flow in the inner channel 10 can be improved on the inner nozzle 14.

Particularly advantageous is an embodiment shown in Figs. 2 and 3, in which a distance 34 between the core 32 and the inner tube 16 is at least two times larger than a core diameter 35. In such a construction, the inner tube 16 in the region of the divider 31st Not or only slightly widened in order to ensure the most constant flow cross-section up to the inner nozzle 14 can. This has the consequence that the outer channel 16 in the region of the outer nozzles 12 may have a larger flow cross-section, so that even in the outer channel 11 to the outer nozzles 12 as constant as possible

Flow cross section can be achieved. Thus, this measure ultimately leads to a reduction of the flow resistance in the gas path of the lance. 3

FIGS. 2 and 3 also show a further special feature, since there the core 32 projects axially from an inner end wall 36 which axially closes the inner duct 10 in the region of the inner nozzles 14. In order to improve the deflection to the inner nozzle 14, a transition 37 from the core 32 to the inner end wall 36 may now be configured kehlförmig. As a result, it is possible to build the divider 31 axially shorter. For the core 32, for example, an axial length 38 is preferred, which is about the same size as or may be smaller than an opening cross section 39 of the inner channel 10 in the region of the inner nozzle 14. This relatively short divider 31 in turn allows expansion in the outer channel 11 and leads there to a reduced flow resistance.

LIST OF REFERENCE NUMBERS

1 combustion chamber

2 hybrid burners

3 lance

4 liquid fuel supply line

5 gas fuel supply line

6 pump

7 air

8 lance head

9 longitudinal center axis of 8

10 inner channel

11 outdoor channel

12 outside nozzle

13 outer nozzle channel

14 inner nozzle

15 inner nozzle channel

16 inner tube

17 outer tube

18 distribution section

19 passage opening

20 circumferential opening width

21 radial opening width

22 footbridge

23 web wall thickness 24 outer end wall

25 transition

26 deepening

27 longitudinal central axis of 12 and 14

28 depth of 26

29 distance between 12 and 14

30 inlet zone

31 dividers

32 core

33 partition

34 distance between 32 and 16

35 core diameter

36 inner end wall

37 throat-shaped transition

38 core length

39 inner channel diameter

Claims

claims

A lance for a hybrid burner (2) of a combustion chamber (1) of a gas turbine, - having an inner duct (10) for a liquid fuel,

with a gaseous fuel external passage (11) coaxially surrounding the inner duct (10),

- with a plurality of star-shaped radially outwardly from the outer channel (11) outgoing outer nozzles (12), - with a plurality of radially from the inner channel (10) outgoing inner nozzles (14), each extending coaxially within one of the outer nozzles (12),

- With an upstream of the outer nozzles (12) in the outer channel (11) arranged distributor portion (18) having a plurality of star-shaped, coaxially extending passage openings (19) for the gaseous fuel, each having a larger opening width in the circumferential direction than in the radial direction.

2. Lance according to claim 1, characterized in that the passage openings (19) each extend in the circumferential direction along a circular arc segment.

3. Lance according to claim 1 or 2, characterized in that - the passage openings (19) in the circumferential direction by radially and axially extending webs (22) are limited, - That the opening width (20) of the through holes (19) in the circumferential direction at least three or about four to eight times greater than a wall thickness (23) of the webs (22) in the circumferential direction.

4. lance according to one of claims 1 to 3, characterized

- That the outer channel (11) in the region of the outer nozzles (12) by an outer end wall (24) is axially closed,

- That in each outer nozzle (12) on an away from the manifold section (18) side in the outer end wall (24) an axial recess (26) is formed.

5. Lance according to claim 4, characterized in that a separate recess (26) is provided for each outer nozzle (12).

6. lance according to claim 5, characterized in that the recess (26) coaxial with the outer nozzle (12) is designed arcuate segment-shaped.

7. lance according to claim 4, characterized in that for all outer nozzles (12) has a common recess (26) is provided, which extends in the circumferential direction closed annular.

8. lance according to one of claims 4 to 7, characterized the depression (26) has a radial depth (28) which is at least twice greater than a radial distance (29) between an inner wall of the outer nozzle (12) and an outer wall of the outer nozzle (12) with respect to a longitudinal center axis (27) of the respective outer nozzle (12) arranged inside nozzle (14).

9. Lance according to one of claims 1 to 8, characterized in that in each outer nozzle (12) has a transition (25) from the outer channel (11) to an inside of the respective outer nozzle (12) formed outer nozzle channel (13) with a in Direction of flow tapered inlet zone (30) is provided.

10. Lance according to one of claims 1 to 9, characterized in that - in the region of the inner nozzles (14) in the inner channel (10) a divider (31) is arranged, a concentric to the inner channel (10) arranged core (32) and star-shaped of which up to a the inner channel (10) radially outwardly bounding inner tube (16) projecting, radially and axially extending partitions (32), - that a distance (34) between the core (32) and the inner tube (16) at least twice larger than a core diameter (35).

11. Lance according to claim 10, characterized in that - the core (32) of the inner channel (10) in the region of the inner nozzles

(14) axially closing the inner end wall (36) projects axially, - that a transition (37) from the core (32) to the inner end wall (36) is designed kehlförmig in longitudinal section.

12. Lance according to claim 10 or 11, characterized in that an axial length (38) of the core (32) is approximately equal to or smaller than an opening cross-section (39) of the inner channel (10) in the region of the inner nozzles (14). ,