EP3421885B1 - Combustion chamber of a gas turbine, gas turbine and method for operating the same - Google Patents

Description

The invention relates to a combustion chamber of a gas turbine according to the preamble of claim 1. The invention also relates to a gas turbine with such a combustion chamber and a method for operating such a gas turbine.

Gas turbines have a combustion chamber and a turbine downstream of the combustion chamber. Fuel is burned in the combustion chamber of a gas turbine, producing hot exhaust gas. The hot exhaust gas is expanded in the turbine of the gas turbine in order to gain energy that can be used to provide drive power, for example to drive a generator to generate electricity. Gas turbines designed as dual-fuel gas turbines are already known from practice, such dual-fuel gas turbines comprising a dual-fuel combustion chamber in which a gaseous fuel is burned in a gaseous fuel operating mode and a liquid fuel is burned in a liquid fuel operating mode. In the gaseous fuel operating mode, a mixture of a gaseous fuel and combustion air can be supplied to the combustion chamber via a swirl body. In the liquid fuel operating mode, the combustion chamber of the gas turbine can be supplied with the liquid fuel via an atomization device and the combustion air via the swirl body.

From the post-published EP 3 351 854 A1 a combustion chamber of a gas turbine according to the preamble of claim 1 is known.

US2015/0082770A1 discloses a dual fuel combustor. This dual-fuel combustion chamber has an atomization device with a central atomization nozzle and a number of decentralized atomization nozzles. Liquid fuel is introduced into the combustion chamber via both the central atomizing nozzle and the decentralized atomizing nozzles into the combustion chamber. Gaseous fuel, on the other hand, is introduced into the combustion chamber exclusively via the decentralized atomization devices.

DE 198 39 085 A1 discloses a burner assembly having primary and secondary pilot burners. Fuel gas and/or fuel oil can be supplied to a main burner. The fuel gas for the main burner is mixed with combustion air in the area of a swirl generator. The fuel oil for the main burner is added to the air directly in the area of the main swirl generator. The pilot burner, which serves to ignite and/or stabilize the main flame in the main burner, is supplied with fuel via additional fuel channels.

There is a need to further improve combustion chambers of a gas turbine designed as dual-fuel combustion chambers to the effect that the liquid fuel can be burned more effectively, particularly in the liquid fuel operating mode, while reducing undesirable exhaust gas emissions such as nitrogen oxide emissions.

Proceeding from this, the present invention is based on the object of creating a novel combustion chamber of a gas turbine, a gas turbine of such a combustion chamber and a method for operating such a gas turbine.

This object is achieved by a combustor of a gas turbine according to claim 1.

The atomizing device has an atomizing lance with at least one atomizing nozzle which is central in relation to a longitudinal center axis of the combustion chamber or in relation to a longitudinal center axis of an antechamber of the combustion chamber. The atomizing device also has a plurality of atomizing nozzles which are decentralized relative to the longitudinal center axis of the combustion chamber or relative to the longitudinal center axis of the antechamber of the combustion chamber.

In the liquid fuel operating mode, the liquid fuel can be optimally introduced into the combustion chamber via the central atomizing lance, which comprises at least one atomizing nozzle, and via the multiple decentralized atomizing nozzles, in order to ensure effective combustion of the liquid fuel. The liquid fuel can be introduced directly into a central recirculation zone within the combustion chamber or the antechamber of the combustion chamber via the central atomization lance, as a result of which stable combustion can be achieved. The introduction of the fuel via the central atomizing lance is not homogeneous with the combustion air, there is no premixing of liquid fuel and combustion air. The liquid fuel can be distributed homogeneously in the combustion air via the decentralized atomizing nozzles. Furthermore, a partial pre-mixing of liquid fuel and combustion air is achieved by the decentralized atomizing nozzles. By means of the decentralized atomizing nozzles, exhaust gas emissions, in particular nitrogen oxide emissions, can be reduced in comparison to the central atomizing lance.

The central atomizing lance has at least two, preferably two, atomizing nozzles which, alone and together, each provide an atomizing cone with a maximum spray angle of 60°, preferably a maximum of 55°. Each of the decentralized atomizing nozzles provides an atomizing cone with a maximum spray angle of 50°, preferably a maximum of 40°. This can be avoided that walls of the combustion chamber and the antechamber of the combustion chamber are wetted with liquid fuel. In particular, this serves to effectively burn the liquid fuel while reducing exhaust emissions.

According to a development of the invention, the decentralized atomizing nozzles are positioned on a circular path extending around the longitudinal center axis of the combustion chamber or around the longitudinal center axis of the antechamber of the combustion chamber. A center point of the circular path on which the decentralized atomizing nozzle is positioned is preferably positioned on the longitudinal central axis of the combustion chamber or the antechamber of the combustion chamber. A radius of the circular path on which the decentralized atomizing nozzles are positioned is preferably between 0.4 times and 1.1 times an inner radius of the swirl body. Via such decentralized atomizing nozzles, the liquid fuel can be optimally introduced into the combustion chamber, providing a homogeneous distribution of the same with the combustion air and with a view to premixing it with the combustion air, in order to reduce exhaust gas emissions such as nitrogen oxide emissions as much as possible.

According to a development of the invention, the central atomizing lance is surrounded at least in sections radially on the outside by an adjacent component, forming a radial gap, with combustion air being able to be supplied to the combustion chamber via the radial gap, bypassing the swirl body. Here too, when using the central atomizing lance for introducing the liquid fuel into the combustion chamber or antechamber of the combustion chamber, effective combustion of the liquid fuel in the liquid fuel operating mode can be ensured with a reduction in nitrogen oxide emissions in particular. The gas turbine according to the invention is defined in claim 8 and the method of operating the same according to the invention is defined in claim 9.

According to a first variant of the method according to the invention, in the liquid fuel operating mode, both the central atomizing lance and the decentralized atomizing nozzles are used in the entire operating range between idling and full load in order to supply the liquid fuel to the combustion chamber. This operating variant of the invention is suitable when the gas turbine to be operated is to carry out rapid load changes, since individual injection nozzles then do not have to be switched on or off. Rinsing procedures that are required when switching off individual atomizing nozzles can thus be avoided. Exhaust emissions can be reduced compared to gas turbines, whose combustion chambers only have a central atomization lance.

According to a second variant of the method according to the invention, in the liquid fuel operating mode in an operating range below a predetermined load limit, both the central atomizing lance (and the decentralized atomizing nozzles are used to supply liquid fuel to the combustion chamber, whereas in an operating range above the predetermined load limit only the decentralized atomizing nozzles are used in order to supply the liquid fuel to the combustion chamber. This operating variant of the invention serves to further reduce exhaust gas emissions, in particular nitrogen oxide emissions. In an upper load range, the central atomization lance is no longer used for introducing the liquid fuel, rather the liquid fuel is introduced in the upper load range Fuel exclusively using the decentralized atomizing nozzles friction area of high loads.

Fig. 1

einen stark schematisierten Ausschnitt aus einer erfindungsgemäßen Brennkammer einer erfindungsgemäßen Gasturbine;

Fig. 2

das Detail II der Fig. 1;

Fig. 3

ein Detail der Fig. 1 in Blickrichtung III;

Fig. 4

ein Diagramm zur Verdeutlichung eines ersten erfindungsgemäßen Verfahrens zum Betreiben der erfindungsgemäßen Gasturbine; und

Fig. 5

ein Diagramm zur Verdeutlichung eines zweiten erfindungsgemäßen Verfahrens zum Betreiben der erfindungsgemäßen Gasturbine.

Preferred developments of the invention result from the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being limited thereto. It shows:

1

a highly schematic section of a combustion chamber according to the invention of a gas turbine according to the invention;

2

the detail II of 1 ;

3

a detail of 1 in line of sight III;

4

a diagram to illustrate a first method according to the invention for operating the gas turbine according to the invention; and

figure 5

a diagram to illustrate a second method according to the invention for operating the gas turbine according to the invention.

The invention relates to a combustion chamber of a gas turbine, a gas turbine with such a combustion chamber and a method for operating such a gas turbine.

1 shows a schematic section from a gas turbine in the area of a combustion chamber 1. The combustion chamber 1 is delimited by a wall 2, with a fuel being burned in the combustion chamber 1. Exhaust gas produced during the combustion of the fuel in the combustion chamber 1 can be supplied to a turbine of the gas turbine (not shown) in order to expand the exhaust gas in the turbine and thereby gain energy.

Combustion chamber 1 is designed as a dual-fuel combustion chamber, which can be operated in a gas fuel operating mode on the one hand and in a liquid fuel operating mode on the other.

In the gas fuel operating mode of the combustion chamber 1, a gaseous fuel is burned in the same, a mixture of the gaseous fuel and combustion air of the combustion chamber 1, in 1 an antechamber 9 of the combustion chamber 1, via a swirl body 3 is supplied.

The swirler 3 is preferably designed as a radial swirler and generates a defined swirl of the mixture of combustion air and gaseous fuel entering the prechamber 9 of the combustion chamber 1 . The mixture of the gaseous fuel and the combustion air is ignited in the gaseous fuel operating mode by means of an electric ignition device, not shown.

In the liquid fuel operating mode of the combustion chamber 1, a liquid fuel is burned in the same, the liquid fuel of the combustion chamber 1, in 1 the antechamber 9 of the combustion chamber 1, with the aid of an atomizing device 4 is supplied.

The atomizing device 4 has a central atomizing lance 17, which is positioned approximately in the middle of the antechamber 9 of the combustion chamber 1 or on a longitudinal center axis 20 of the antechamber 9 of the combustion chamber 1 or on a longitudinal center axis 20 of the combustion chamber 1 and which emits the liquid fuel in Direction of the longitudinal center axis 20 to form an atomization cone or spray cone 8a in the antechamber 9 of the combustion chamber 1 injected.

In addition to this atomizing lance 17 which is central in relation to the longitudinal center axis 20 of the combustion chamber 1 or the antechamber 9, the atomizing device 4 has a plurality of atomizing nozzles 18 which are decentralized in relation to the longitudinal center axis 20 of the combustion chamber 1 or the antechamber 9 and which spray liquid fuel can also inject into the antechamber 9 of the combustion chamber 1, with the formation of a respective spray cone 8b.

The atomizing device 4 therefore has the central atomizing lance 17 and several decentralized atomizing nozzles 18. The central atomizing lance 17 has at least one atomizing nozzle, preferably several atomizing nozzles 15, 16 (see 2 ).

2 shows a detail of the central atomizing lance 17 of the atomizing device 4. Between the atomizing lance 17, which is accommodated in a mounting wall 12 of the combustion chamber 1, and an adjoining component 5, which is also accommodated in the mounting wall 12 and which is radially outwardly attached to the atomizing lance 17 of the atomizing device 4 and which surrounds the atomizing lance 17 of the atomizing device 4 radially on the outside at least in sections, a radial gap 6 is formed, via which combustion air can also be fed to the combustion chamber 1, namely the antechamber 9, specifically bypassing the swirl body 3. So visualized an arrow 13 (see 1 ) a flow of combustion air over the swirl body 3 and an arrow 14 (see 2 ) a flow of combustion air over the radial gap 6 between the atomizing lance 17 and the component 5, the flow of combustion air over this radial gap 6 being adjusted via a valve 25.

That component 15 which defines the annular gap 6 together with the atomizing lance 17 of the atomizing device 4 is preferably designed as a separate sleeve which is accommodated in the mounting wall 12 . In contrast to this, it is also possible for the mounting wall 12 itself to provide the component 5 which adjoins the atomizing lance 17 radially on the outside and which together with the atomizing lance 17 defines the radial gap 6 .

The atomizing nozzles 8 of the atomizing device 4, which are decentralized with respect to the longitudinal center axis 20 of the combustion chamber 1 or antechamber 9, are preferably on a circular path 19 (see FIG 3 ) positioned, which extends around the longitudinal center axis 20 of the combustion chamber 1 or the longitudinal center axis 20 of the antechamber 9 of the combustion chamber 1 .

A center point of this circular path 19, on which the decentralized atomizing nozzles 18 are positioned, is positioned on the longitudinal central axis 20. The decentralized atomizing nozzles 18 accordingly surround the central atomizing lance 17 preferably concentrically.

3 shows a radius d ₁₈ of the circular path 19 on which the decentralized atomizing nozzles 18 are arranged. It is provided in particular that this radius d ₁₈ of the circular path 19 on which the decentralized atomizing nozzles 18 are positioned is between 0.4 times and 1.1 times an inner diameter d ₃ of the swirl body 3 . When the radius d ₁₈ of the circular path 19 on which the decentralized atomizing nozzles 18 are arranged is between 1.0 and 1.1 times the inner diameter d ₃ of the swirler 3, the decentralized atomizing nozzles 18 at least partially overlap the swirl body 3 in the area of its exit area.

The decentralized atomizing nozzles 18 can also be arranged on a plurality of preferably concentric circular paths or on an elliptical path or a polygon.

As already stated, the central atomizing lance 17 of the atomizing device 4 preferably comprises a plurality of atomizing nozzles, in the exemplary embodiment of FIG 2 two atomizing nozzles 15, 16, which are preferably swirl atomizing nozzles. These two atomizing nozzles 15, 16 of the central atomizing lance 17, the liquid fuel can be supplied in the liquid fuel operating mode starting from a common liquid fuel supply 21, with the fuel guided by the liquid fuel supply 21 being able to be divided into two liquid fuel partial supplies 21a, 21b in order to have both atomizing nozzles 15, 16 of the central atomizing lance 17 to supply liquid fuel.

The central atomizing lance 17 with its two atomizing nozzles 15, 16 sprays the liquid fuel in the direction of the combustion chamber 1 at the spray angle α, which is a maximum of 60°, preferably a maximum of 55°. Both when both atomizing nozzles 15, 16 of the atomizing lance 17 are operated together and when one of these atomizing nozzles 15, 16 is operated alone, the spray angle α is a maximum of 60°, preferably a maximum of 55°. This ensures that neither the walls 2a of the prechamber 9 nor the walls 2 of the combustion chamber 1 are wetted with liquid fuel, as a result of which more effective combustion of the liquid fuel can be provided.

As already stated, combustion air can be supplied to the combustion chamber 1 , in particular to the antechamber 9 , via the gap 6 . The air flow 14, which is guided through this annular gap 6, serves on the one hand to cool the central atomizing lance 17 of the atomizing device 4, and on the other hand this air flow 14 at least partially surrounds the spray cone 8a of the liquid fuel of the atomizing lance 17 on the outside and thus bundles it.

The combustion air 14 which the combustion chamber 1, in 1 of the antechamber 9, bypassing the swirl body 3 via the radial gap 6, is in particular between 1% and 10% of the combustion air, which can be supplied to the combustion chamber via the swirl body 3.

The combustion air flow 14 can be supplied not only to the combustion chamber 1 in the liquid fuel operating mode, but also to the combustion chamber 1 in the gaseous fuel operating mode via the radial gap 6, with the atomizing device 4, i.e. in particular the atomizing lance 17 of the same, being inactive in the gaseous fuel operating mode, so that then in the gaseous fuel operating mode via the atomizing device 4 no fuel is introduced, only via the swirl body 3.

As already explained, the atomizing lance 17 is aligned centrally, in relation to the longitudinal central axis 20. Liquid fuel can be introduced into a central recirculation zone via the atomizing lance 17 in the liquid fuel operating mode. This ensures a very stable combustion. The introduction of the liquid fuel via the central atomization lance 17 in relation to the longitudinal center axis 20 therefore takes place locally, that is to say not homogeneously with respect to the combustion air, so that no premixing of liquid fuel and combustion air takes place.

As already stated, the combustion chamber 1 comprises, in addition to the central atomizing lance 17, a plurality of decentralized atomizing nozzles 18 which are preferably arranged on the circular path 19. These decentralized atomizing nozzles 18 are connected via a separate liquid fuel supply 22 (see 1 ) can be supplied with liquid fuel, with the decentralized atomizing nozzles 18 introducing the liquid fuel into the antechamber 9 or combustion chamber 1 in approximately the same direction as the central atomizing lance 17, but with a spray angle β that is smaller than the spray angle α, the spray angle β of the decentralized atomizing nozzles 18 preferably being at most 50°, preferably at most 40°.

With the help of the decentralized atomizing nozzles 18, which are preferably evenly distributed over the circular path 19, the fuel is introduced into the combustion chamber 1, in particular into the antechamber 9, forming a homogeneous distribution with the combustion air; at the same time, a partial premixing of combustion air and liquid fuel is provided, in particular supported by the fact that the decentralized atomizing nozzles 18 are arranged adjacent to the outlet of the swirl body 3 . This partial premixing can be improved if the radius d ₁₈ is larger than the radius d ₃ . Thus, the radius d ₁₈ can be between 1.0 times and 1.1 times the radius d ₃ .

Double jet nozzles or so-called plain jets are preferably used as decentralized atomizing nozzles 18 . A homogeneous supply of the liquid fuel to the combustion air is achieved via the decentralized atomizing nozzles 18, and also a partial premixing of liquid fuel and combustion air.

When the combustion chamber 1 is to be operated in the gaseous fuel operating mode, a mixture of gas and combustion air is supplied to the combustion chamber 1 via the swirl body 3 .

Combustion air can also be routed via the annular gap 6 in the gaseous fuel operating mode. The combustion air flow 14 conducted via the annular gap 6 is branched off in the region of an air space, a so-called plenum 10, upstream of the swirl body 3.

So shows 1 an air line 11, via which combustion air can be branched off from the plenum 10, the combustion air 14 branched off from the plenum 10 via the air line 11 being supplied to an air chamber 7 formed by the wall 12, in order then, starting from this air chamber 7, via the between the annular gap 6 formed by the atomizing lance 17 of the atomizing device 4 and the adjacent component 5 into the antechamber 9 of the combustion chamber 1 .

When combustion chamber 1 is operated in liquid fuel operating mode with active atomization device 4, liquid fuel is supplied to combustion chamber 1 or prechamber 9 via atomization device 4, combustion air via swirl body 3 and preferably via annular gap 6 between central atomization lance 17 and the component 5

In a first advantageous operating mode, both the central atomizing lance 17 and the decentralized atomizing nozzles 18 of the atomizing device 4 are used in the liquid fuel operating mode in the entire operating range between idle and full load to supply the combustion chamber 1 with the liquid fuel.

For this first operating case, in 4 Several curves 21, 22, 23 and 24 are shown above the load L of the gas turbine, with curve 21 corresponding to the liquid fuel supply 21 via the central atomizing lance 17, with curve 22 corresponding to the liquid fuel supply 22 via the decentralized atomizing nozzle 18, with curve 23 corresponding to the Load portion of the total load L shows that can be provided by the combustion of the liquid fuel introduced via the central atomizing lance 17, and the curve 24 shows the load portion of the total load L that can be provided by the combustion of the fuel that can be provided via the decentralized Atomizing nozzles 18 is introduced into the combustion chamber.

So shows 4 That if over the entire load range between 0% (idle) and 100% (full load) both via the central atomizing lance 17 as fuel is also supplied to the combustion chamber 1 via the decentralized atomizing nozzles 18, a constant quantity of liquid fuel is preferably supplied to the combustion chamber 1 in the entire operating range between idling (0%) and full load (100%) via the central atomizing lance 17 (see curve 21). The power modulation then takes place by changing the liquid fuel introduced into the combustion chamber 1 via the decentralized atomizing nozzles 18 (see curve 22), so that as the load requirement L increases, the load component 23 of the central atomizing lance 17 falls compared to the load component of the decentralized atomizing nozzles 18 or the corresponding load component 24 of the decentralized atomizing nozzles 18 increases.

According to this operating concept, in which both the central atomizing lance 17 and the decentralized atomizing nozzles 18 are used in the entire load range or operating range between idle and full load in order to supply the liquid fuel to the combustion chamber, it is provided in particular that to ignite the combustion in the combustion chamber 1, fuel is introduced into the combustion chamber 1 exclusively via one of the two atomizing nozzles 15, 16 of the atomizing lance 17, and that after ignition and after a defined speed of the gas turbine has been reached, both atomizing nozzles 15, 16 of the atomizing lance 17 are used to inject the fuel via to introduce the atomizing lance 17 into the combustion chamber 1.

As already stated, over the entire operating range and thus the load range of the gas turbine according to the operating concept 4 the amount of fuel provided via the central atomizing lance 17 is constant, the power modulation takes place exclusively via the variation of the amount of fuel provided via the decentralized atomizing nozzles 18 . This operating concept is particularly suitable for rapid load changes on the gas turbine, since then, apart from the ignition process, no atomizing nozzles have to be switched on or off. Also it is not necessary after turning off atomizing nozzles to rinse the same. This operating concept serves a very robust and stable combustion of the liquid fuel. In addition, low fuel emissions can be realized, in particular nitrogen oxide emissions of less than 150 vppm.

figure 5 illustrates a second operating concept of the combustion chamber according to the invention or of the gas turbine according to the invention comprising the combustion chamber according to the invention. So shows figure 5 that the load range L between idle (0%) and full load (100%) is divided into two load ranges, namely a load range between idle (0%) and a limit value GW, and a load range between a limit value GW and Full load (100%).

After the second operating concept of the invention figure 5 In the liquid fuel operating mode, both the central atomizing lance 17 and the decentralized atomizing nozzles 18 are used in the operating range or load range below the specified load limit GW in order to supply liquid fuel to the combustion chamber 1 . The amount of fuel introduced via the central atomizing lance 17 (see curve 21) is preferably constant in this load range, and the power modulation then takes place exclusively via the change in the amount of liquid fuel introduced via the decentralized atomizing nozzles 18 (see curve 22).

In the load range above the defined limit value GW, the central atomizing lance 17 is switched off, so that no more fuel is then supplied via the same, so that in the upper load range between the load limit GW and full load (100%) liquid fuel is supplied exclusively via the decentralized atomizing nozzles 18 of the combustion chamber 1 is supplied.

One advantage of this second operating concept according to the invention is that at loads above the defined load limit GW, the liquid fuel is not introduced centrally into the recirculation zone of the combustion chamber 1, but exclusively decentralized, so that all liquid fuel introduced is introduced homogeneously with the combustion air and is partially premixed can be guaranteed with combustion air, whereby exhaust emissions, especially nitrogen oxide emissions, compared to the operating concept of 4 can be further reduced. In particular, nitrogen oxide emissions of less than 90 vppm can be realized.

Reference List

1

combustion chamber

2

Wall

2a

Wall

3

swirler

4

atomization device

5

component

6

radial gap

7

airspace

8a

atomization cone

8b

atomization cone

9

antechamber

10

Airspace / Plenum

11

air line

12

Wall

13

combustion air flow

14

combustion air flow

15

atomizing nozzle

16

atomizing nozzle

17

atomizing lance

18

atomizing nozzle

19

circular path

20

longitudinal central axis

21

liquid fuel delivery

21a

Liquid fuel part feed

21b

Liquid fuel part feed

22

liquid fuel delivery

23

load share

24

load share

25

Valve

Claims (13)

1. A combustor (1) of a gas turbine, for combusting a fuel in the presence of combustion air, wherein the combustor (1) is designed as a dual-fuel combustor,

   having a pre-chamber (9),

   having a swirl body (3),

   wherein the pre-chamber (9) of the combustor (1) designed as dual-fuel combustor (1) can be supplied in a gas fuel operating mode via the swirl body (3) with a mixture of a gaseous fuel and combustion air, and

   wherein the pre-chamber (9) of the combustor (1) designed as dual-fuel combustor can be supplied in a liquid fuel operating mode via an atomisation device (4) with a liquid fuel and via the swirl body (3) with combustion air, the atomisation device (4) comprises an atomisation lance (17) that is central based on a longitudinal centre axis (20) of the combustor (1) or based on a longitudinal centre axis (20) of a pre-chamber (9) of the combustor (1) having at least two atomisation nozzles (15, 16), which alone and jointly each provide an atomisation cone (8a) having a maximum spray angle (α) of 60°,

   wherein the atomisation device (4) comprises multiple atomisation nozzles (18) decentralised based on the longitudinal centre axis (20) of the combustor (1) or based on the longitudinal centre axis (20) of the pre-chamber (9) of the combustor (1),

   wherein each of the decentralised atomisation nozzles (18) provides an atomisation cone (8b) each having a maximum spray angle (β) of 50°, which is smaller than the spray angle (α) of the at least two atomisation nozzles (15, 16) of the central atomisation lance (17) .
2. The combustor according to Claim 1, characterised in that the decentralised atomisation nozzles (18) are positioned on a circular path (19) extending about the longitudinal centre axis (20) of the combustor or about the longitudinal centre axis (20) of the pre-chamber of the combustor.
3. The combustor according to Claim 2, characterised in that a centre point of the circular path (19), on which the decentralised atomisation nozzles (18) are positioned on the longitudinal centre axis (20) of the combustor (1) or the pre-chamber (9) of the combustor (1) .
4. The combustor according to Claim 2 or 3, characterised in that a radius of the circular path (19), on which the decentralised atomisation nozzles (18) are positioned, amounts to between 0.4 times and 1.1 times of an inside radius of the swirl body (3).
5. The combustor according to any one of the Claims 1 to 4, characterised in that the central atomisation lance (17), forming a radial gap (6) radially outside, is surrounded by an adjoining component (5) at least in portions, wherein the combustor (1) can be supplied via the radial gap (6) with combustion air, bypassing the swirl body (3).
6. The combustor according to Claim 5, characterised in that the combustion airflow, which can be supplied to the combustor (1) bypassing the swirl body (3) via the radial gap (6) between the atomisation lance (17) of the atomisation device (4) and the adjoining component (5) amounts to between 1% and 10% of the combustion airflow, which can be supplied to the combustor via the swirl body (3).
7. The combustor according to Claim 5 or 6, characterised in that the combustor, both in the gas fuel operating mode and also in the liquid fuel operating mode, can be supplied with combustion air via the radial gap (6) between the atomisation lance (17) of the atomisation device (4) and the adjoining component (5).
8. A gas turbine,

   having a combustor (1) according to any one of the Claims 1 to 7 for combusting a fuel in the presence of combustion air,

   having a turbine for expanding the exhaust gas developing during the combustion.
9. A method for operating a gas turbine according to Claim 8, characterised in that

   the combustor (1) in the gas fuel operating mode is supplied via the swirl body with a mixture of a gaseous fuel and combustion air (3),

   the combustor (1) in the liquid fuel operating mode is supplied via the atomisation device (4) with a liquid fuel and with combustion air at least via the swirl body (3).
10. The method according to Claim 9, characterised in that in the liquid fuel operating mode both the central atomisation lance (17) as well as the decentralised atomisation nozzles (18) can be utilised throughout the operating range between no-load and full-load in order to supply the combustor (1) with the liquid fuel.
11. The method according to Claim 10, characterised in that via the central atomisation lance (17) throughout the operating range between no-load and full-load a constant quantity of liquid fuel is supplied to the combustor (1), wherein the power modulation is carried out by changing a quantity of the liquid fuel supplied to the combustor (1) via the decentralised atomisation nozzles (18).
12. The method according to Claim 9, characterised in that in the liquid fuel operating mode in an operating range below a predetermined load limit both the central atomisation lance (17) and also the decentralised atomisation nozzles (18) are utilised in order to supply the liquid fuel to the combustor (1), whereas in an operating range above the predetermined load limit exclusively the decentralised atomisation nozzles (18) are utilised in order to supply the combustor (1) with the liquid fuel.
13. The method according to Claim 12, characterised in that in the operating range below the predetermined load limit a constant quantity of liquid fuel is supplied via the central atomisation lance (17), wherein the power modulation is carried out by changing a quantity of the liquid fuel supplied to the combustor (1) via the decentralised atomisation nozzles (18).

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