(19)
(11)EP 3 320 268 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
29.04.2020 Bulletin 2020/18

(21)Application number: 16734654.3

(22)Date of filing:  04.07.2016
(51)International Patent Classification (IPC): 
F23R 3/28(2006.01)
F23R 3/14(2006.01)
F23R 3/36(2006.01)
F02C 3/20(2006.01)
(86)International application number:
PCT/EP2016/065712
(87)International publication number:
WO 2017/005694 (12.01.2017 Gazette  2017/02)

(54)

BURNER FOR A GAS TURBINE AND METHOD FOR OPERATING THE BURNER

BRENNER FÜR EINE GASTURBINE UND VERFAHREN ZUM BETRIEB DES BRENNERS

BRÛLEUR POUR TURBINE À GAZ ET PROCÉDÉ D'EXPLOITATION DU BRÛLEUR


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 06.07.2015 EP 15175472

(43)Date of publication of application:
16.05.2018 Bulletin 2018/20

(73)Proprietor: Siemens Aktiengesellschaft
80333 München (DE)

(72)Inventors:
  • BULAT, Ghenadie
    Lincoln LN6 8BD (GB)
  • MAY, Jonathan
    Lincoln LN6 9HL (GB)


(56)References cited: : 
EP-A1- 1 568 942
EP-A1- 2 472 179
WO-A1-2015/037295
US-A1- 2004 226 297
EP-A1- 2 317 098
EP-A2- 2 378 203
US-A1- 2003 056 517
US-A1- 2009 301 096
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description


    [0001] The invention relates to a burner for a gas turbine and a method for operating the burner.

    [0002] A burner is conventionally designed for a specific fuel, for example natural gas, diesel, syngas or landfill gas. However, when the burner that was designed for one fuel is operated with a different fuel, then the operation of the burner will not be optimal. The operation with the different fuel can result in a flashback that can lead to a flame burning on the burner surface, a flameout, combustion dynamics that effect the integrity of the burner, a high pressure drop that leads to a performance loss, or high emissions, for example high emissions of NOx.

    [0003] In addition to conventional hydrocarbon fuels, synthetic fuels like hydrogen can be used in the burner. The combustion of the synthetic fuels differ from the combustion of conventional fluids in particular in respect to diffusivity, caloric value, ignition temperatures and flame speeds. For example, the combustion of hydrogen with air occurs at higher flame speeds than the combustion of natural gas with air. Therefore, in case that hydrogen is used in a burner that is designed for natural gas, this can result in a flashback.

    [0004] EP 2 472 179 (A1) discloses a burner assembly extending along a longitudinal axis and comprises a premix burner provided with: a first supply channel for supplying a first gas mixture; a second supply channel for supplying a second gas mixture; an air flow channel; a swirler arranged along the air flow channel; a plurality of first outlets for supplying the first mixture; and at least a second outlet for supplying the second mixture; the second outlet is arranged along an inner wall of the air flow channel at the outlet of the swirler.

    [0005] WO 2015/037295 A1 discloses a multi-fuel-supporting gasturbine combustor comprising: a main burner that supplies a premixed gas including a first fuel to a first combustion region inside a combustion chamber; and a reheating burner that supplies a second fuel having a different composition from the first fuel to a second combustion region downstream of a first combustion region inside the combustion chamber. The first fuel is a hydrocarbon-based fuel, and the second fuel is a gas including hydrogen in a concentration exceeding the stable combustion limit concentration for hydrogen.

    [0006] EP 2 378 203 A2 discloses a premixer including a peripheral wall defining a mixing chamber therein through which a flow path for a fluid is defined, a nozzle including an annular splitter plate disposed in the flow path within the mixing chamber. The splitter plate including a trailing edge defined in relation to a predominant direction of fluid flow along the flow path and being formed to define a fuel line therein, which is receptive of oil fuel and an annular array of fuel injectors disposed at the trailing edge, which are each fluidly communicative with the fuel line and configured to inject at least the oil fuel into the flow path with the oil fuel being substantially atomized upon injection or substantially immediately after the injection by interaction with the fluid flowing along the flow path.

    [0007] It is an object of the invention to provide a burner and a method for operating the burner, wherein the burner can be operated with different fuels with good combustion properties.

    [0008] The burner according to the invention is defined by the features of independent claim 1. The burner is adapted to premix the fuel with an air flow before the fuel enter the reaction zone of the combustion chamber such that a first fuel flow of the first fuel has a first premixing stream line and a second fuel flow of the second fuel has a second premixing stream line, wherein each of the premixing stream lines begin at the fuel injection into the air flow and end at the location where the fuel enters the reaction zone and the length of the second premixing stream line is longer than the length of the first premixing stream line, the length of the first premixing stream line is between and including 0.25 x D2 and 1 x D2 and the length of the second premixing stream line is between and including 0.5 x D2 and 1.5 x D2. The burner comprises a third injector adapted to inject a third fuel being less reactive than the second fuel into the combustion chamber, wherein a third fuel flow of the third fuel has a third premixing stream line with a length that is longer than the length of the second premixing stream line.

    [0009] The method according to the invention for operating a burner is defined by the features of independent claim 9.

    [0010] With the burner and the method for operating the burner according to the invention it is advantageously achieved that the best premixing of each fuel stream with air can be achieved. Therefore, a single and correct location for the reaction zone can be achieved which results in a stable flame that is tolerant to load changes or changes of the ratio of the first fuel and second fuel. Furthermore, because of the good premixing of each fuel low emissions, in particular of NOx, can be achieved.

    [0011] It is conceivable that the first fuel is hydrogen and the second fuel is natural gas. Alternatively, it is conceivable that the first fuel is hydrogen and the second fuel is ammonia gas. It is also conceivable that the first fuel is natural gas and that the second fuel is ammonia gas. The first fuel increases the flame stability. The first fuel also enables the combustion of the low reactive ammonia gas.

    [0012] It is preferred that the first injector and the second injector are located such that the first fuel is injected into the air flow downstream in respect to the direction of the air flow from where the second fuel is injected into the air flow, so that the length of the second premixing stream line is longer than the length of the first premixing stream line. This provides an easy way to ensure the different lengths of the premixing stream lines.

    [0013] The burner comprises a third injector adapted to inject a third fuel being less reactive than the second fuel into the combustion chamber, wherein a third fuel flow of the third fuel has a third premixing stream line with a length that is longer than the length of the second premixing stream line. This allows advantageously the combustion of three different fuels, hence increasing the flexibility of the burner. It is preferred that the third injector is located such that the third fuel is injected into the air flow upstream in respect to the direction of the air flow from where the second fuel is injected into the air flow, so that the length of the third premixing stream line is longer than the length of the second premixing stream line.

    [0014] It is preferred that the first fuel is hydrogen, the second fuel is natural gas and the third fuel is ammonia gas. Here, the hydrogen serves mainly for flame stabilisation. The natural gas serves as a backup for the case when no hydrogen is available. The ammonia gas provides most of the power output. The third premixing fuel stream line is the longest of the three premixing stream lines, hence advantageously compensating for the low diffusivity of the ammonia gas.

    [0015] It is preferred that the length of the first premixing stream line is from 20 mm to 150 mm, in particular from 40 mm to 60 mm, the length of the second premixing stream line is from 40 mm to 300 mm, in particular from 80 mm to 120 mm, and the length of the third premixing stream line is from 60 mm to 400 mm, in particular from 125 mm to 175 mm. Here, the premixing stream lines are defined as a time average, hence compensating for fluctuations of the reaction zone. These lengths provide optimal premixing conditions for each of the fuels, in particular when hydrogen, natural gas and ammonia gas are used for first fuel, the second fuel and the third fuel, respectively.

    [0016] The length L3 of the third premixing stream line may be between and including 1 x D2 and 3 x D2.

    [0017] The relationship between the premixing tube length (X2) and its diameter may be between 0.4 and 0.6 x X2 and may be approximately D2 = 0.5 x X2.

    [0018] It is preferred that the burner comprises a third injector adapted to inject a third fuel being less reactive than the second fuel into the combustion chamber, wherein a third fuel flow of the third fuel has a third premixing stream line with a length that is longer than the length of the second premixing stream line and the method comprises the step: - injecting the third fuel and at least one of the first fuel and the second fuel into the combustion chamber during a base load operation of the gas turbine. The first fuel and/or second fuel advantageously serve to stabilise the combustion of the third fuel. During the base load operation the injected volume of the first fuel and the second fuel is preferably up to 20 vol-% of the total fuel injected into the combustion chamber. Alternatively, it is preferred that during the base load operation the injected volume of the third fuel is up to 95 vol-% of the total fuel injected into the combustion chamber. Under these conditions, a stable operation of the combustion is advantageously achieved.

    [0019] The burner comprises the third injector adapted to inject a third fuel being less reactive than the second fuel into the combustion chamber, wherein a third fuel flow of the third fuel has a third premixing stream line that is longer than the second premixing stream line and the method comprises the step: - injecting at least one of the first fuel and the second fuel and not the third fuel into the combustion chamber during an ignition process or a part load operation of the gas turbine. By operating the burner in this manner it is advantageously achieved that the ignition process is reliable and during part load operation a flameout is unlikely.

    [0020] It is preferred that the first fuel is hydrogen, the second fuel is natural gas and the third fuel is ammonia gas.

    [0021] The method preferably comprises following steps: (a) determining if a value of a temperature of a part of the burner to be protected from overheating has exceeded a predetermined maximum limit; (b) if so, changing at least one ratio of the fuel mass flows such as to reduce the value of the temperature below its predetermined maximum limit; if not, go to (c); (c) determining if a value of the amplitude of pressure variations within a combustion area of the burner has exceeded a predetermined maximum limit; (d) if so, changing said at least one ratio such as to reduce the value of the amplitude below its predetermined maximum limit; if not, go to (e); (e) repeat (a) to (d) such as to maintain the values of the temperature the amplitude below their respective predetermined maximum limits. By operating the burner in this manner it is advantageously achieved that the pressure oscillations within the combustion system are reduced and that the temperature of critical parts of the burner are reduced which results in a long life time of the burner.

    [0022] The above mentioned attributes and other features and advantages of this invention and the manner of attaining them will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein

    FIG. 1 shows part of a gas turbine in a sectional view and in which the present inventive burner is incorporated,

    FIG. 2 shows a longitudinal section of the burner and

    FIG. 3 shows another longitudinal section of the burner.



    [0023] FIG. 1 shows an example of a gas turbine 10 in a sectional view. The gas turbine engine 10 comprises, in flow series, an inlet 12, a compressor section 14, a combustor section 16 and a turbine section 18 which are generally arranged in flow series and generally about and in the direction of a longitudinal or rotational axis 20. The gas turbine engine 10 further comprises a shaft 22 which is rotatable about the rotational axis 20 and which extends longitudinally through the gas turbine engine 10. The shaft 22 drivingly connects the turbine section 18 to the compressor section 14.

    [0024] In operation of the gas turbine engine 10, air 24, which is taken in through the air inlet 12 is compressed by the compressor section 14 and delivered to the combustion section or burner section 16. The burner section 16 comprises a burner plenum 26, one or more combustion chambers 28 and at least one burner 30 fixed to each combustion chamber 28. The combustion chambers 28 and the burners 30 are located inside the burner plenum 26. The compressed air passing through the compressor 14 enters a diffuser 32 and is discharged from the diffuser 32 into the burner plenum 26 from where a portion of the air enters the burner 30 and is mixed with a gaseous or liquid fuel. The air/fuel mixture is then burned and the combustion gas 34 or working gas from the combustion is channelled through the combustion chamber 28 to the turbine section 18 via a transition duct 17.

    [0025] This exemplary gas turbine engine 10 has a cannular combustor section arrangement 16, which is constituted by an annular array of combustor cans 19 each having the burner 30 and the combustion chamber 28, the transition duct 17 has a generally circular inlet that interfaces with the combustor chamber 28 and an outlet in the form of an annular segment. An annular array of transition duct outlets form an annulus for channelling the combustion gases to the turbine 18.

    [0026] The turbine section 18 comprises a number of blade carrying discs 36 attached to the shaft 22. In the present example, two discs 36 each carry an annular array of turbine blades 38. However, the number of blade carrying discs could be different, i.e. only one disc or more than two discs. In addition, guiding vanes 40, which are fixed to a stator 42 of the gas turbine engine 10, are disposed between the stages of annular arrays of turbine blades 38. Between the exit of the combustion chamber 28 and the leading turbine blades 38 inlet guiding vanes 44 are provided and turn the flow of working gas onto the turbine blades 38.

    [0027] The combustion gas from the combustion chamber 28 enters the turbine section 18 and drives the turbine blades 38 which in turn rotate the shaft 22. The guiding vanes 40, 44 serve to optimise the angle of the combustion or working gas on the turbine blades 38.

    [0028] The turbine section 18 drives the compressor section 14. The compressor section 14 comprises an axial series of vane stages 46 and rotor blade stages 48. The rotor blade stages 48 comprise a rotor disc supporting an annular array of blades. The compressor section 14 also comprises a casing 50 that surrounds the rotor stages and supports the vane stages 48. The guide vane stages include an annular array of radially extending vanes that are mounted to the casing 50. The vanes are provided to present gas flow at an optimal angle for the blades at a given engine operational point. Some of the guide vane stages have variable vanes, where the angle of the vanes, about their own longitudinal axis, can be adjusted for angle according to air flow characteristics that can occur at different engine operations conditions.

    [0029] The casing 50 defines a radially outer surface 52 of the passage 56 of the compressor 14. A radially inner surface 54 of the passage 56 is at least partly defined by a rotor drum 53 of the rotor which is partly defined by the annular array of blades 48.

    [0030] The present invention is described with reference to the above exemplary turbine engine having a single shaft or spool connecting a single, multi-stage compressor and a single, one or more stage turbine. However, it should be appreciated that the present invention is equally applicable to two or three shaft engines and which can be used for industrial, aero or marine applications.

    [0031] Figures 2 and 3 show that the burner 30 comprises an inner wall 101 that confines the combustion chamber 28 in a radial direction. Furthermore, the burner 30 comprises a burner plate 106 that confines that combustion chamber 28 in an axial direction. As it can be seen in Figure 3, the burner 30 comprises an outer wall 102 that is arranged radially outside of the inner wall 101. The inner wall 101 and the outer wall 102 can be rotationally symmetric around a burner axis 35 of the burner. The air 24 is streamed in the space between the inner wall 101 and the outer wall 102 towards the burner plate 106 as indicated by arrows 108, so that the inner wall 101 is cooled and the air 24 is preheated before it enters the combustion chamber 28. The inner wall 101 can also be a double skin arrangement for cooling efficiencies.

    [0032] The burner 30 comprises a swirler 107 located on the base plate 106 for swirling the air before it enters the combustion chamber 28. After passing the space between the inner wall 101 and the outer wall 102 the air 24 passes through the swirler 107 in a direction towards the burner axis 35 and enters the combustion chamber 28.

    [0033] The burner 30 comprises a first injector 103 adapted to inject a first fuel into the combustion chamber 28, a second injector 104 adapted to inject a second fuel into the combustion chamber 28 and a third injector 105 adapted to inject a third fuel into the combustion chamber 28. The second fuel is less reactive than the first fuel and the third fuel is less reactive than the second fuel. This can be achieved for example, when the first fuel is hydrogen, the second fuel is natural gas and the third fuel is ammonia gas.

    [0034] The burner 30 is adapted to premix these fuels with an air flow before the fuels enter a reaction zone 109 of the combustion chamber 28 such that a first fuel flow of the first fuel has a first premixing stream line 112, a second fuel flow of the second fuel has a second premixing stream line 113 and a third fuel flow of the third flow has a third premixing stream line 114. Each of the premixing stream lines at the fuel injection into the air flow and ends at the location where the fuel enters the reaction zone 109.

    [0035] The injectors 103, 104 and 105 are arranged in the base plate 106, wherein the first injector 103 is located closer to the burner axis 35 than the second injector 104 and the second injector 104 is located closer to the burner axis 35 than the third injector 105. Therefore, the first fuel is injected into the air flow downstream in respect to the direction of the air flow from where the second fuel is injected into the air flow, so that the length L2 of the second premixing stream line 113 is longer than the length L1 of the first premixing stream line 112. Furthermore, the third injector 105 is located such that the third fuel is injected into the air flow upstream in respect to the direction of the air flow from where the second fuel is injected into the air flow, so that the length L3 of the third premixing stream line 114 is longer than the length L2 of the second premixing stream line 113.

    [0036] The length L1 of the first premixing stream line 112 is from 20 mm to 150 mm, in particular from 40 mm to 60 mm, the length L2 of the second premixing stream line 113 is from 40 mm to 300 mm, in particular from 80 mm to 120 mm, and the length L3 of the third premixing stream line 114 is from 60 mm to 400 mm, in particular from 125 mm to 175 mm.

    [0037] In a relative and scalable definition of the present arrangement, the length L1 of the first premixing stream line 112 is between and including 0.25 x D2 and 1 x D2, the length L2 of the second premixing stream line 113 is between and including 0.5 x D2 and 1.5 x D2. The length L3 of the third premixing stream line 114 is between and including 1 x D2 and 3 x D2. The relationship between the premixing tube length (X2) and its diameter (D2) is typically about 0.5 i.e D2 = 0.5 x X2 and can be between 0.4 and 0.6 x X2. For the present arrangement this relationship is without considering the swirler 107 height (axial extent).

    [0038] The premixer tube or pre-chamber, defined by inner wall 101, is of a generally constant diameter D2. The pre-chamber, generally denoted by 29 in Figs.2 and 3, is located downstream of the swirler and upstream of the main combustion chamber 28. In normal operation the combustion flames are held within the combustion chamber 28. Mixing of air and fuels occur within the swirler 107 and pre-chamber 29. Slight variations in pre-chamber diameter are possible, but careful design is required to maintain the combustion flame within the combustion chamber 28 and downstream of the pre-chamber 29.

    [0039] In an embodiment of the present burner, the first injectors 103 are located radially inwardly of the second injectors 104 and the third injectors 105 and the second injectors 104 are located radially inwardly of the third injectors 105. The first injector 103 and second injector 104 are located at least partly in the swirler vane 107 such that fuel is injected immediately away from the surface of the vane 107. Alternatively, the first injector 103 and/or second injector 104 can be located such that it extends through the burner plate 106 and effectively injects fuel immediately away from the base plate's surface, i.e. in an axial direction. In this embodiment, the third injector 105 is located further away from or axially away from the first injector 103 and second injector 104.

    [0040] The first injector 103 is located radially inwardly of the swirler vane 107 so that the fuel is directed into the correct part of the airflow through the passageway. The location of the first, second and third injectors 103, 104 &105 can be related to one another diameter (D2). The first injector 103 is typically at 0.5 x D2 +/- 5% of D2. The first injector 103 is located a distance of the downstream edge of the swirler vane 107 within 5% of D2. In one embodiment, second and third injectors 104, 105 are both located approximately the same radial distance D3 = 1.6 x D2. In for other embodiments, second and third injectors 104, 105 have radial locations D3 and D4 respectively which can each be between 1.2 x D2 and 3.0 x D2. Where the third injector 105 injects an ammonia-based fuel, a relatively long radial length increases the time for mixing with the air flow and vaporisation.

    [0041] Although only one injector orifice is shown on the Figures to represent each of the first, second and third injectors 103, 104 and 105 respectively, each injector may have more than one injector orifice. Any dimension or parameter given for its location is to the centre of the orifices or mid-point between orifices.

    [0042] The annular array of swirler vanes 107, burner plate 106 and wall 116 define an annular array of passageways 115. These passageways 115 have a central axis 117 (see Fig.3), which in the viewing-plane of Figs.2 and 3 is radially aligned. Nonetheless, angles from a radial line up to 15 degrees are possible in other embodiments. The swirler vanes 107 are also arranged such that the passageways 115 also have a tangential angle relative to the axis 35 as is know from the art. Thus this tangential angle creates the vortex of fuel and air about the axis 35.

    [0043] It should be appreciated that the specific ranges of parameters set forth herein give rise to stable and efficient flames within the present burner arrangement. This is with particular respect to the types of fuels being burnt and their injection locations. Parameters outside those given herein result in relatively poor mixing of fuels and air and subsequent problems with efficiency, emissions and flame stability. The specified parameters ensure that fuels are correctly introduced into the air stream 108 passing through the swirler passages 115 such that each fuel type is burnt within the correct part of the flame 109.

    [0044] It is conceivable that a multitude of first injectors 103 is arranged in the burner plate 106, each having the same distance to the burner axis 35. It is conceivable that a multitude of second injectors 104 is arranged in the burner plate 106, each having the same distance to the burner axis 35. It is conceivable that a multitude of third injectors 105 is arranged in the burner plate 106, each having the same distance to the burner axis 35.

    [0045] The flame in the combustion chamber 28 has an inner recirculation zone 110 that stabilises the flame by transporting hot combustion products to the unburned air/fuel mixture, and an outer recirculation zone 111.

    [0046] The burner can be operated during an ignition process or during a part load operation of the gas turbine 10 such that only the first fuel and/or second fuel is injected into the combustion chamber 28. During a base load operation of the gas turbine 10 the third fuel and at least one of the first fuel and second fuel is injected into the combustion chamber 28.

    [0047] Furthermore, the burner 30 can be operated with an intelligent control of the fuel injection with the steps: (a) determining if a value of a temperature of a part of the burner 30 to be protected from overheating has exceeded a predetermined maximum limit; (b) if so, changing at least one ratio of the fuel mass flows such as to reduce the value of the temperature below its predetermined maximum limit; if not, go to (c); (c) determining if a value of the amplitude of pressure variations within a combustion area of the burner 30 has exceeded a predetermined maximum limit; (d) if so, changing said at least one ratio such as to reduce the value of the amplitude below its predetermined maximum limit; if not, go to (e); (e) repeat (a) to (d) such as to maintain the values of the temperature the amplitude below their respective predetermined maximum limits. It is conceivable to change said ratio in such a manner that the power output of the burner remains unchanged.


    Claims

    1. Burner for a gas turbine (10), wherein the burner (30) comprises
    a combustion chamber (28),
    a burner axis (35),
    a burner plate (106) that confines the combustion chamber in an axial direction,
    an annular array of swirler vanes (107) located on the burner plate (106),
    a wall (116),
    the annular array of swirler vanes (107), the burner plate (106) and the wall (116) defining a swirler with an annular array of passageways (115), the passageways (115) have a central axis (117) that is radially aligned,
    a premixing tube (101), located downstream of the swirler and upstream of the combustion chamber (28), having a constant diameter (D2) and a length (X2),
    a first injector (103) adapted to inject a first fuel into the combustion chamber (28) and
    a second injector (104) adapted to inject a second fuel being less reactive than the first fuel into the combustion chamber (28), wherein
    the burner (30) is adapted to premix these fuels with an air flow before the fuel enters a reaction zone (109) of the combustion chamber (28) such that a first fuel flow of the first fuel has a first premixing stream line (112) and a second fuel flow of the second fuel has a second premixing stream line (113), wherein
    each of the premixing stream lines begins with the beginning of the premixing with the air flow and ends at the location where the fuel enters the reaction zone (109) and the length (L2) of the second premixing stream line (113) is longer than the length (L1) of the first premixing stream line (112), characterised in that
    the length (L1) of the first premixing stream line (112) is between and including 0.25 x D2 and 1 x D2 and the length (L2) of the second premixing stream line (113) is between and including 0.5 x D2 and 1.5 x D2,
    wherein the burner (30) comprises a third injector (105) adapted to inject a third fuel being less reactive than the second fuel into the combustion chamber (28), wherein a third fuel flow of the third fuel has a third premixing stream line (114) with a length (L3) that is longer than the length (L2) of the second premixing stream line (113).
     
    2. Burner according to claim 1, wherein the first injector (103) and the second injector (104) are located such that the first fuel is injected into the air flow downstream in respect to the direction of the air flow from where the second fuel is injected into the air flow, so that the length (L2) of the second premixing stream line (113) is longer than the length (L1) of the first premixing stream line (112).
     
    3. Burner according to any one of claims 1-2, wherein the third injector (105) is located such that the third fuel is injected into the air flow upstream in respect to the direction of the air flow from where the second fuel is injected into the air flow, so that the length (L3) of the third premixing stream line (114) is longer than the length (L2) of the second premixing stream line (113).
     
    4. Burner according to any one of claims 1-3, wherein the first fuel is hydrogen, the second fuel is natural gas and the third fuel is ammonia gas.
     
    5. Burner according to any one of claims 1 to 4, wherein the length (L1) of the first premixing stream line (112) is from 20 mm to 150 mm, in particular from 40 mm to 60 mm, the length (L2) of the second premixing stream line (113) is from 40 mm to 300 mm, in particular from 80 mm to 120 mm, and the length (L3) of the third premixing stream line (114) is from 60 mm to 400 mm, in particular from 125 mm to 175 mm.
     
    6. Burner according to any one of claims 1 to 5, wherein the length L3 of the third premixing stream line (114) is between and including 1 x D2 and 3 x D2.
     
    7. Burner according to any one of claims 1 to 6, wherein the relationship between the premixing tube length (X2) and its diameter (D2) is between 0.4 and 0.6 x X2.
     
    8. Burner according to any one of claims 1 to 6, wherein the relationship between the premixing tube length (X2) and its diameter (D2) is approximately D2 = 0.5 x X2.
     
    9. Method for operating a burner (30) for a gas turbine (10), wherein the burner (30) as claimed in any one of claims 1-8, with the step:

    - injecting at least one of the fuels into the combustion chamber (28).


     
    10. Method according to claim 9, with the step:

    - injecting the third fuel and at least one of the first fuel and the second fuel into the combustion chamber (28) during a base load operation of the gas turbine (10).


     
    11. Method according to claim 10, wherein during the base load operation the injected volume of the first fuel and the second fuel is up to 20 vol-% of the total fuel injected into the combustion chamber (28).
     
    12. Method according to claim 10, wherein during the base load operation the injected volume of the third fuel is up to 95 vol-% of the total fuel injected into the combustion chamber (28).
     
    13. Method according to claim 9, wherein the burner (30) comprises a third injector (105) adapted to inject a third fuel being less reactive than the second fuel into the combustion chamber (28), wherein a third fuel flow of the third fuel has a third premixing stream line (114) that is longer than the second premixing stream line (113), with the step:

    - injecting at least one of the first fuel and the second fuel and not the third fuel into the combustion chamber (28) during an ignition process or a part load operation of the gas turbine (10).


     
    14. Method according to any one of claims 10 to 13, wherein the first fuel is hydrogen, the second fuel is natural gas and the third fuel is ammonia gas.
     
    15. Method according to any one of claims 9 to 14, with the steps:

    (a) determining if a value of a temperature of a part of the burner (30) to be protected from overheating has exceeded a predetermined maximum limit;

    (b) if so, changing at least one ratio of the fuel mass flows such as to reduce the value of the temperature below its predetermined maximum limit; if not, go to (c);

    (c) determining if a value of the amplitude of pressure variations within a combustion area of the burner (30) has exceeded a predetermined maximum limit;

    (d) if so, changing said at least one ratio such as to reduce the value of the amplitude below its predetermined maximum limit; if not, go to (e);

    (e) repeat (a) to (d) such as to maintain the values of the temperature the amplitude below their respective predetermined maximum limits.


     


    Ansprüche

    1. Brenner für eine Gasturbine (10), wobei der Brenner (30) Folgendes umfasst:

    eine Brennkammer (28),

    eine Brennerachse (35),

    eine Brennerplatte (106), die die Brennkammer in axialer Richtung begrenzt,

    eine ringförmige Anordnung von Drallschaufeln (107), die sich an der Brennerplatte (106) befinden,

    eine Wand (116),

    wobei die ringförmige Anordnung von Drallschaufeln (107), die Brennerplatte (106) und die Wand (116) einen Drallerzeuger mit einer ringförmigen Anordnung von Durchgängen (115) definieren, die eine radial ausgerichtete Mittelachse (117) aufweisen,

    ein Vormischrohr (101) mit einem konstanten Durchmesser (D2) und einer Länge (X2), das sich stromabwärts von dem Drallerzeuger und stromaufwärts von der Brennkammer (28) befindet,

    eine erste Einspritzdüse (103), die so ausgelegt ist, dass sie einen ersten Brennstoff in die Brennkammer (28) einspritzt, und

    eine zweite Einspritzdüse (104), die so ausgelegt ist, dass sie einen zweiten Brennstoff in die Brennkammer (28) einspritzt, der weniger reaktionsfreudig ist als der erste Brennstoff, wobei

    der Brenner (30) so ausgelegt ist, dass er diese Brennstoffe mit einem Luftstrom vormischt, bevor der Brennstoff in eine Reaktionszone (109) der Brennkammer (28) strömt, so dass ein erster Brennstoffstrom des ersten Brennstoffs eine erste Vormischströmungsleitung (112) und ein zweiter Brennstoffstrom des zweiten Brennstoffs eine zweite Vormischströmungsleitung (113) aufweist, wobei

    jede der Vormischströmungsleitungen am Anfang des Vormischens mit dem Luftstrom beginnt und an der Stelle endet, wo der Brennstoff in die Reaktionszone (109) strömt, und die Länge (L2) der zweiten Vormischströmungsleitung (113) größer ist als die Länge (L1) der ersten Vormischströmungsleitung (112), dadurch gekennzeichnet, dass

    die Länge (L1) der ersten Vormischströmungsleitung (112) 0,25 x D2 bis 1 x D2 und die Länge (L2) der zweiten Vormischströmungsleitung (113) 0,5 x D2 bis 1,5 x D2 beträgt,

    wobei der Brenner (30) eine dritte Einspritzdüse (105) umfasst, die so ausgelegt ist, dass sie einen dritten Brennstoff in die Brennkammer (28) einspritzt, der weniger reaktionsfreudig ist als der zweite Brennstoff, wobei ein dritter Brennstoffstrom des dritten Brennstoffs eine dritte Vormischströmungsleitung (114) mit einer Länge (L3) aufweist, die größer ist als die Länge (L2) der zweiten Vormischströmungsleitung (113).


     
    2. Brenner nach Anspruch 1, wobei die erste Einspritzdüse (103) und die zweite Einspritzdüse (104) so angeordnet sind, dass der erste Brennstoff in Bezug auf die Richtung des Luftstroms von da aus, wo der zweite Brennstoff in den Luftstrom eingespritzt wird, stromabwärts in den Luftstrom eingespritzt wird, so dass die Länge (L2) der zweiten Vormischströmungsleitung (113) größer ist als die Länge (L1) der ersten Vormischströmungsleitung (112).
     
    3. Brenner nach einem der Ansprüche 1 und 2, wobei die dritte Einspritzdüse (105) so angeordnet ist, dass der dritte Brennstoff in Bezug auf die Richtung des Luftstroms von da aus, wo der zweite Brennstoff in den Luftstrom eingespritzt wird, stromaufwärts in den Luftstrom eingespritzt wird, so dass die Länge (L3) der dritten Vormischströmungsleitung (114) größer ist als die Länge (L2) der zweiten Vormischströmungsleitung (112).
     
    4. Brenner nach einem der Ansprüche 1 bis 3, wobei es sich bei dem ersten Brennstoff um Wasserstoff, bei dem zweiten Brennstoff um Erdgas und bei dem dritten Brennstoff um Ammoniakgas handelt.
     
    5. Brenner nach einem der Ansprüche 1 bis 4, wobei die Länge (L1) der ersten Vormischströmungsleitung (112) 20 mm bis 150 mm, insbesondere 40 mm bis 60 mm, die Länge (L2) der zweiten Vormischströmungsleitung (113) 40 mm bis 300 mm, insbesondere 80 mm bis 120 mm und die Länge (L3) der dritten Vormischströmungsleitung (114) 60 mm bis 400 mm, insbesondere 125 mm bis 175 mm beträgt.
     
    6. Brenner nach einem der Ansprüche 1 bis 5, wobei die Länge L3 der dritten Vormischströmungsleitung (114) 1 x D2 bis 3 x D2 beträgt.
     
    7. Brenner nach einem der Ansprüche 1 bis 6, wobei das Verhältnis zwischen der Vormischrohrlänge (X2) und seinem Durchmesser (D2) zwischen 0,4 und 0,6 x X2 beträgt.
     
    8. Brenner nach einem der Ansprüche 1 bis 6, wobei das Verhältnis zwischen der Vormischrohrlänge (X2) und seinem Durchmesser (D2) etwa D2=0,5 x X2 beträgt.
     
    9. Verfahren zum Betreiben eines Brenners (30) für eine Gasturbine (10), wobei der Brenner (30) einem der Ansprüche 1 bis 8 entspricht, mit folgendem Schritt:

    - Einspritzen mindestens eines der Brennstoffe in die Brennkammer (28).


     
    10. Verfahren nach Anspruch 9 mit folgendem Schritt:

    - Einspritzen des dritten und des ersten und/oder des zweiten Brennstoffs in die Brennkammer (28) bei einem Grundlastbetrieb der Gasturbine (10).


     
    11. Verfahren nach Anspruch 10, wobei das eingespritzte Volumen des ersten und des zweiten Brennstoffs bei Grundlastbetrieb bis zu 20 Vol.-% des insgesamt in die Brennkammer (28) eingespritzten Brennstoffs beträgt.
     
    12. Verfahren nach Anspruch 10, wobei das eingespritzte Volumen des dritten Brennstoffs bei Grundlastbetrieb bis zu 95 Vol.-% des insgesamt in die Brennkammer (28) eingespritzten Brennstoffs beträgt.
     
    13. Verfahren nach Anspruch 9, wobei der Brenner (30) eine dritte Einspritzdüse (105) umfasst, die so ausgelegt ist, dass sie einen dritten Brennstoff in die Brennkammer (28) einspritzt, der weniger reaktionsfreudig ist als der zweite Brennstoff, wobei ein dritter Brennstoffstrom des dritten Brennstoffs eine dritte Vormischströmungsleitung (114) aufweist, die länger ist als die zweite Vormischströmungsleitung (113), mit folgendem Schritt:

    - Einspritzen des ersten und/oder des zweiten und nicht des dritten Brennstoffs in die Brennkammer (28) bei einem Zündvorgang oder einem Teillastbetrieb der Gasturbine (10).


     
    14. Verfahren nach einem der Ansprüche 10 bis 13, wobei es sich bei dem ersten Brennstoff um Wasserstoff, bei dem zweiten Brennstoff um Erdgas und bei dem dritten Brennstoff um Ammoniakgas handelt.
     
    15. Verfahren nach einem der Ansprüche 9 bis 14 mit folgenden Schritten:

    a) Bestimmen, ob ein Wert einer Temperatur eines vor Überhitzung zu schützenden Teils des Brenners (30) eine vorgegebene Höchstgrenze überschritten hat,

    b) wenn dies der Fall ist, derartiges Ändern mindestens eines Verhältnisses der Brennstoffmassenströme, dass der Temperaturwert unter seine vorgegebene Höchstgrenze sinkt, und wenn dies nicht der Fall ist, Übergang zu c),

    c) Bestimmen, ob ein Wert der Amplitude von Druckschwankungen innerhalb eines Verbrennungsbereichs des Brenners (30) eine vorgegebene Höchstgrenze überschritten hat,

    d) wenn dies der Fall ist, derartiges Ändern des mindestens einen Verhältnisses, dass der Amplitudenwert unter seine vorgegebene Höchstgrenze sinkt, und wenn dies nicht der Fall ist, Übergang zu e),

    e) Wiederholen von a) bis d), so dass die Werte für die Temperatur und die Amplitude unter ihrer jeweiligen vorgegebenen Höchstgrenze bleiben.


     


    Revendications

    1. Brûleur pour turbine à gaz (10), étant entendu que le brûleur (30) comprend :

    une chambre de combustion (28) ;

    un axe (35) de brûleur ;

    une plaque (106) de brûleur qui délimite la chambre de combustion dans une direction axiale ;

    un agencement annulaire d'aubes fixes (107) de générateur de turbulences situées sur la plaque (106) de brûleur ;
    une paroi (116),
    l'agencement annulaire d'aubes fixes (107) de générateur de turbulences, la plaque (106) de brûleur et la paroi (116) définissant un générateur de turbulences doté d'un agencement annulaire de passages (115), les passages (115) ayant un axe central (117) qui est aligné dans une direction radiale ;

    un tube de prémélange (101), situé en aval du générateur de turbulences et en amont de la chambre de combustion (28), possédant un diamètre constant (D2) et une longueur (X2) ;

    un premier injecteur (103) adapté en vue d'injecter un premier combustible dans la chambre de combustion (28), et

    un deuxième injecteur (104) adapté en vue d'injecter dans la chambre de combustion (28) un deuxième combustible qui est moins réactif que le premier combustible, étant entendu que :
    le brûleur (30) est adapté en vue de prémélanger ces combustibles avec un flux d'air avant que le combustible n'entre dans une zone de réaction (109) de la chambre de combustion (28) de telle sorte qu'un premier flux de combustible du premier combustible ait une première ligne de courant (112) de prémélange et qu'un deuxième flux de combustible du deuxième combustible ait une deuxième ligne de courant (113) de prémélange, étant entendu :
    que chacune des lignes de courant de prémélange commence avec le commencement du prémélange avec le flux d'air et finit à l'endroit où le combustible entre dans la zone de réaction (109), et que la longueur (L2) de la deuxième ligne de courant (113) de prémélange est plus longue que la longueur (L1) de la première ligne de courant (112) de prémélange, caractérisé en ce que :

    la longueur (L1) de la première ligne de courant (112) de prémélange fait entre, et inclut, 0,25 x D2 et 1 x D2 et en ce que la longueur (L2) de la deuxième ligne de courant (113) de prémélange fait entre, et inclut, 0,5 x D2 et 1,5 x D2,

    étant entendu que le brûleur (30) comprend un troisième injecteur (105) adapté en vue d'injecter dans la chambre de combustion (28) un troisième combustible qui est moins réactif que le deuxième combustible, étant entendu qu'un troisième flux de combustible du troisième combustible a une troisième ligne de courant (114) de prémélange d'une longueur (L3) qui est plus longue que la longueur (L2) de la deuxième ligne de courant (113) de prémélange.


     
    2. Brûleur selon la revendication 1, étant entendu que le premier injecteur (103) et le deuxième injecteur (104) sont situés de telle sorte que le premier combustible soit injecté dans le flux d'air en aval, par rapport au sens du flux d'air, de l'endroit d'où le deuxième combustible est injecté dans le flux d'air, de sorte que la longueur (L2) de la deuxième ligne de courant (113) de prémélange soit plus longue que la longueur (L1) de la première ligne de courant (112) de prémélange.
     
    3. Brûleur selon l'une quelconque des revendications 1-2, étant entendu que le troisième injecteur (105) est situé de telle sorte que le troisième combustible soit injecté dans le flux d'air en amont, par rapport au sens du flux d'air, de l'endroit d'où le deuxième combustible est injecté dans le flux d'air, de sorte que la longueur (L3) de la troisième ligne de courant (114) de prémélange soit plus longue que la longueur (L2) de la deuxième ligne de courant (113) de prémélange.
     
    4. Brûleur selon l'une quelconque des revendications 1-3, étant entendu que le premier combustible est de l'hydrogène, que le deuxième combustible est du gaz naturel et que le troisième combustible est du gaz ammoniac.
     
    5. Brûleur selon l'une quelconque des revendications 1 à 4, étant entendu que la longueur (L1) de la première ligne de courant (112) de prémélange fait de 20 mm à 150 mm, en particulier de 40 mm à 60 mm, que la longueur (L2) de la deuxième ligne de courant (113) de prémélange fait de 40 mm à 300 mm, en particulier de 80 mm à 120 mm, et que la longueur (L3) de la troisième ligne de courant (114) de prémélange fait de 60 mm à 400 mm, en particulier de 125 mm à 175 mm.
     
    6. Brûleur selon l'une quelconque des revendications 1 à 5, étant entendu que la longueur (L3) de la troisième ligne de courant (114) de prémélange fait entre, et inclut, 1 x D2 et 3 x D2.
     
    7. Brûleur selon l'une quelconque des revendications 1 à 6, étant entendu que la relation entre la longueur (X2) du tube de prémélange et son diamètre (D2) fait entre 0,4 et 0,6 x X2.
     
    8. Brûleur selon l'une quelconque des revendications 1 à 6, étant entendu que la relation entre la longueur (X2) du tube de prémélange et son diamètre (D2) fait approximativement D2 = 0,5 x X2.
     
    9. Procédé d'utilisation d'un brûleur (30) pour turbine à gaz (10), étant entendu le brûleur (30) selon l'une quelconque des revendications 1-8, comportant l'étape consistant :

    - à injecter au moins l'un des combustibles dans la chambre de combustion (28).


     
    10. Procédé selon la revendication 9, comportant l'étape consistant :

    - à injecter le troisième combustible et au moins soit le premier combustible, soit le deuxième combustible, dans la chambre de combustion (28) pendant une utilisation en charge de base de la turbine à gaz (10).


     
    11. Procédé selon la revendication 10, étant entendu que, pendant l'utilisation en charge de base, le volume injecté du premier combustible et du deuxième combustible va jusqu'à 20 % en vol. de la totalité du combustible injecté dans la chambre de combustion (28).
     
    12. Procédé selon la revendication 10, étant entendu que, pendant l'utilisation en charge de base, le volume injecté du troisième combustible va jusqu'à 95 % en vol. de la totalité du combustible injecté dans la chambre de combustion (28).
     
    13. Procédé selon la revendication 9, étant entendu que le brûleur (30) comprend un troisième injecteur (105) adapté en vue d'injecter dans la chambre de combustion (28) un troisième combustible qui est moins réactif que le deuxième combustible, étant entendu qu'un troisième flux de combustible du troisième combustible possède une ligne de courant (114) de prémélange qui est plus longue que la deuxième ligne de courant (113) de prémélange, comportant l'étape consistant :

    - à injecter au moins soit le premier combustible, soit le deuxième combustible, et pas le troisième combustible dans la chambre de combustion (28) pendant un processus d'allumage ou une utilisation en charge partielle de la turbine à gaz (10).


     
    14. Procédé selon l'une quelconque des revendications 10 à 13, étant entendu que le premier combustible est de l'hydrogène, que le deuxième combustible est du gaz naturel et que le troisième combustible est du gaz ammoniac.
     
    15. Procédé selon l'une quelconque des revendications 9 à 14, comportant les étapes consistant :

    (a) à déterminer si une valeur d'une température d'une pièce du brûleur (30) à protéger d'une surchauffe a dépassé une limite maximale prédéterminée ;

    (b) si oui, à modifier au moins un rapport des débits massiques de combustible de sorte à abaisser la valeur de la température en dessous de sa limite maximale prédéterminée ; si non, à passer à (c) ;

    (c) à déterminer si une valeur de l'amplitude des variations de pression à l'intérieur d'une zone de combustion du brûleur (30) a dépassé une limite maximale prédéterminée ;

    (d) si oui, à modifier ledit au moins un rapport de sorte à abaisser la valeur de l'amplitude en dessous de sa limite maximale prédéterminée ; si non, à passer à (e) ;

    (e) à répéter (a) à (d) de sorte à maintenir les valeurs de la température et de l'amplitude en dessous de leurs limites maximales prédéterminées respectives.


     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description