Method for operating a gas turbine group

Technical application

0001The present invention relates to a method for operating a gas turbine group according to the preamble of claim 1. It further relates to a gas turbine group for carrying out the method.

State of the art

0002The stability of combustion in modern premix burners of gas turbines is crucially dependent on the ignitability of the fuel used, but also on other fuel properties, in particular the calorific value or the Wobbe index.

0003Such Vormischbrenner are for example from the <patcit id="pcit0001" dnum="EP321809A"><text>EP 321 809</text></patcit>, of the <patcit id="pcit0002" dnum="EP780629A"><text>EP 780,629</text></patcit>, of the <patcit id="pcit0003" dnum="WO9317279A"><text>WO 93/17279</text></patcit>, or the <patcit id="pcit0004" dnum="WO9219913A"><text>WO 92/19913</text></patcit> known. The burner design is based on the common idea to introduce fuel into a twisted combustion air flow and to produce as homogeneous and usually substoichiometric, lean fuel-air mixture. During the transition into the combustion chamber, the swirl flow bursts at a cross-sectional transition, whereby a backflow region forms in front of the burner mouth, which serves for flame stabilization. The flame must not be stabilized too close to the burner mouth to avoid a thermal overload of the burner. However, if the stabilization zone is too far downstream of the burner mouth, instabilities will occur.

0004The location of the combustion zone is also critically dependent on the ignitability of the fuel used. This changes dramatically when, for example, a fuel gas high levels of higher saturated hydrocarbons, such as ethane, butane, propane, also as C₂₊-Alkane designated having. Since the fuel-air mixture is supplied premixed, there is an acute risk of a flashback to the burner. A component failure is then probable.

0005A similar problem is also evident in the operation of self-igniting combustion chambers of <patcit id="pcit0005" dnum="EP669500A"><text>EP 669,500</text></patcit> of a known type, for example in a gas turbine group with sequential combustion, as shown <patcit id="pcit0006" dnum="EP620362A"><text>EP 620 362</text></patcit> has become known. Again, caused by increased ignitability of the fuel gas flashback can lead to a Grosshavarie.

0006A changed fuel gas composition also has effects on emissions and on combustion chamber pulsations.

0007In addition to the content of C₂₊Alkanols also have the calorific value or the Wobbe index an influence on the behavior of the combustion. In premix burner systems, this influence is primarily due to the changed momentum ratio of fuel gas and air at different Wobbe numbers.<patcit id="pcit0007" dnum="US6082092A"><text>US 6,082,092</text></patcit> indicates to regulate a variable fuel gas preheat so that the Wobbe index is kept constant. A regulation to a constant Wobbe index would also be possible by the variable admixture of inert components in a closed loop.<patcit id="pcit0008" dnum="DE19731209"><text>DE 197 31 209</text></patcit> Proposes that the combustion of residual gases of widely varying composition should keep the Wobbe index constant by means of a controlled admixture of natural gas and nitrogen.

0008Out <patcit id="pcit0009" dnum="DE19921981A1"><text>DE 199 21 981 A1</text></patcit> It is known to determine the fuel calorific value and to control the fuel mass flow according to this specification. But also<patcit id="pcit0010" dnum="DE19921981"><text>DE 199 21 981</text></patcit> There is no indication as to how a changed ignitability of the gas and a resulting risk of flashback should be countered.

0009The prior art, however, gives no indication as to an altered fuel gas composition in terms of C content₂₊Alkanes to react. It should be noted that sustained damage due to a flashback can occur very quickly. A procedure in which modified C₂₊Alkane contents in the fuel gas of a gas turbine group to be reacted, therefore, must work almost instantaneously. Controlled constant maintenance of the fuel gas properties is potentially too sluggish, so that instead of a closed-loop control, controlled intervention in an open timing chain is to be preferred.

Presentation of the invention

0010The invention is therefore based on the object to provide a method of the type mentioned, which is able to avoid the disadvantages of the prior art. The method should be particularly suitable for reacting to changes in the relevant fuel properties when operating a gas turbine group with fuel gas. This reaction must be fast enough, for example, in strong variations of the C₂₊-Alkangehaltes to avoid a flashback.

0011The object is achieved by using the entirety of the features of claim 1. Advantageous and preferred embodiments will be apparent from the dependent subclaims.

0012The core of the invention is therefore to arrange at the fuel gas supply to the gas turbine group with advantage without delay in real time operating device for determining combustion gas properties, and incorporate several so determined combustion gas properties en in the control system of the gas turbine group. Depending on the fuel gas property then targeted intervention on parameters of the gas turbine group are made, which influence the combustion.

0013The relevant fuel property is in particular the C₂₊Alkane content of the fuel, which directly affects the risk of flashback. In addition, the calorific value or the Wobbe index can also be used directly as a further fuel gas property in carrying out the method.

0014An essential prerequisite for the function of the method is that the measurement is very fast, and that the measured values ​​are available in real time if possible. In a preferred embodiment, therefore, an infrared measurement technique, as used by<nplcit id="ncit0001" npl-type="s"><text>Hoppe and Wolf in IR Instrument For Gas Property Determination In Industrial Processes, IGRC 2001, Amsterdam, 6.11.2001</text></nplcit> was presented. It is proposed to determine the infrared absorption by the fuel gas in two different spectral ranges. It is proposed to determine the absorption in a first spectral range around 3.5 μm, which reacts primarily to the content of ethane, propane, and butane, and in a second spectral range around 7.9 μm, where the absorption essentially depends on the methane content of the sample gas reacts. The cross-sensitivity between the spectral regions is low, and can easily be corrected if necessary. In this way, the C₂₊Alkane content can be determined continuously and quickly. In principle, the measurement is only sufficient in C for carrying out the method according to the invention₂₊Alkane-sensitive spectral range around 3.5 μm. This is completely sufficient for a qualitative determination of a changed fuel gas composition and for a corresponding reaction; more accurate and necessary for quantitative information is the measurement in both wavelength ranges. In an advantageous embodiment of the method, the infrared absorption is additionally determined in a wavelength range of 4.3 microns, which primarily on the CO₂Content reacts. An extension to other spectral ranges, which are sensitive to specific gas components, is also possible. In a further preferred development, the thermal conductivity as a measure of the nitrogen (N₂) Content. Optionally, using cross sensitivity correction algorithms, the fuel gas composition in this way can be determined very accurately continuously and in real time. This also allows the determination of the calorific value or the Wobbe index.

0015The inventive method can be used with advantage on a gas turbine group with sequential combustion, as they are made <patcit id="pcit0011" dnum="EP620362A"><text>EP 620 362</text></patcit> has become known, and with great advantage, if the second combustion chamber, a self-igniting combustion chamber of <patcit id="pcit0012" dnum="EP620403A"><text>EP 620 403</text></patcit> or <patcit id="pcit0013" dnum="EP669500A"><text>EP 669,500</text></patcit> known type is arranged. Self-igniting combustion chambers are particularly at risk from flashback due to the high mixture temperature. In a gas turbo group of this type, the fuel distribution between the first and the second combustion chamber is changed according to the invention, depending on the fuel properties, for example, such that with increasing C₂₊Content of the second combustion chamber supplied amount of fuel is reduced and the amount of fuel supplied to the first amount of fuel is increased accordingly.

0016Out <patcit id="pcit0014" dnum="EP1199516A"><text>EP 1 199 516</text></patcit> It has become known to make a central Axialluftströmung variable in premix burners. In connection with the method according to the invention, it is advantageous to intervene in this axial flow as a function of the fuel properties determined in this way. For example, with increasing C₂₊Alkane content of the fuel gas, the axial flow are intensified, so as to avoid the risk of flashback in the burner interior.

0017Premix burners of the types used today frequently have a plurality of fuel feeds which can be subjected to fuel independently of one another, for example for the independent application of pilot fuel, which is burned in a diffusion combustion mode <i>becomes</i>, and <i>premix</i>, on. Such burners show, for example<patcit id="pcit0015" dnum="WO0196785A"><text>WO 01/96785</text></patcit>. <patcit id="pcit0016" dnum="EP193838A"><text>EP 193 838</text></patcit>. <patcit id="pcit0017" dnum="EP108361A"><text>EP 108,361</text></patcit>. <patcit id="pcit0018" dnum="WO0012936A"><text>WO 00/12936</text></patcit>. <patcit id="pcit0019" dnum="EP945677A"><text>EP 945 677</text></patcit>, or <patcit id="pcit0020" dnum="EP321809A"><text>EP 321 809</text></patcit>, Depending on the measured fuel properties, the distribution of the fuel can be changed to ensure on the one hand sufficient flame stability and at the same time to avoid flashback or component overheating and to keep the emission values ​​approximately constant.

0018Within a multi-burner system, which is familiar to the person skilled in the art, in one embodiment of the invention, the fuel distribution between individual burners and / or burner groups is varied depending on the measured fuel properties.

0019Likewise, depending on the fuel properties, an inert medium can either be introduced into the fuel gas, this introduction preferably taking place as close as possible to the gas turbine group, which ensures short reaction times. Furthermore, an inert medium, in particular steam or water, can be introduced into the combustion zone as a function of the measured fuel properties. The latter measure is particularly suitable for gas turbine groups, which are already equipped with water and / or steam injection for emission control, since this also proves to be well suited for controlling the flame position and combustion stability. In principle, for example, nitrogen or carbon dioxide would also be suitable as an inert medium, although water and steam are generally more readily available.

0020Another possibility for intervention exists when the gas turbine group has means for cooling the working fluid in front of the compressor or in the compressor or between compressor stages. By a stronger cooling the temperature of the combustion air is lowered, and thus reduces the ignitability. It is also known to realize the cooling by the introduction of a liquid, such as water, in front of the compressor or in the compressor, for example, water droplets penetrate into the compressor and evaporate during compression. This has become popular in the recent past under the names "Wet Compression", "High Fogging", or "Overfogging", and has been used, for example, in the<patcit id="pcit0021" dnum="US2786626A"><text>US 2,786,626</text></patcit> described while the <patcit id="pcit0022" dnum="FR1563749"><text>FR 1,563,749</text></patcit> indicates the positive effects on the performance data of a gas turbine group. The resulting moistening of the combustion air further reduces the ignitability.

0021In a further embodiment of the invention, the gas turbine group is intervened directly in the protective system of the gas turbine group as a function of the measured fuel properties, such that, for example, when the determined C is exceeded₂₊-Alkan concentration, the fuel supply or the power setpoint of the gas turbine group are reduced. Furthermore, when a further limit value is exceeded, a protective intervention can take place such that an immediate shutdown of the gas turbine group takes place.

0022Of course, these different types of intervention on the gas turbine group also readily combine taking into account the plant-specific circumstances. Within the scope of the invention, it is also possible in particular to combine the measured combustion gas properties with other measured values ​​of the gas turbine group, such as pulsation and / or emission measured values, with a measured flame position, with material temperatures, and the like, in order to carry out the interventions on the operation of the gas turbine group.

Short description of the drawings

0023The invention will be explained in more detail with reference to embodiments in conjunction with the drawings. Show it:<ul><li><figref idrefs="f0001">FIG. 1</figref> a gas turbine group with sequential combustion for operation according to the inventive method;</li><li><figref idrefs="f0002">FIG. 2</figref> a first burner type and its operation according to the inventive method;</li><li><figref idrefs="f0002">FIG. 3</figref> a second burner type and their operation according to the inventive method;</li><li><figref idrefs="f0003">FIG. 4</figref> a third burner type and its operation according to the inventive method;</li><li><figref idrefs="f0004">FIG. 5</figref> a multi-burner system and its operation according to the inventive method; and</li><li><figref idrefs="f0005">FIG. 6</figref> a further example of a gas turbine group operated according to the invention.</li></ul>

0024The embodiments and the figures are to be understood purely instructive and should not be used to limit the invention characterized in the claims.

Ways to carry out the invention

0025In <figref idrefs="f0001">FIG. 1</figref> a first example of the execution of the inventive method is shown. A compressor 1, a first turbine 6, and a second turbine 10 are arranged on a common shaft 12. Furthermore, a generator 13 is coupled to the same shaft train. The compressor 1 sucks in ambient air 2. This is compressed and flows as compressed combustion air 3 to a first combustion chamber 4. Typically, but by no means restrictive, this may be a combustor equipped with premix burners of the type cited above. In the combustion chamber 4, the combustion air 3 is a fuel amount ṁ_EV measured and burnt. The resulting hot and tense flue gas 5 flows to the first turbine 6 and is partially released there, giving a shaft power, typically with a pressure ratio of 2. Partly expanded flue gas 7 leaves with still high temperature from the turbine 6 and flows to a second combustion chamber eighth to. This may be, for example, a combustion chamber of<patcit id="pcit0023" dnum="EP669500A"><text>EP 669,500</text></patcit> act of known type. The flue gas 7, which has an oxygen content of about 15% to 17%, is another fuel quantity ṁ_SEV metered and burned in the combustion chamber 8. The reheated flue gas 9 flows to a second turbine 10, and is again relaxed while passing through the second turbine 10 with delivery of a shaft power, this time approximately to ambient pressure. It is basically a gas turbine group of<patcit id="pcit0024" dnum="EP620362A"><text>EP 620 362</text></patcit> known type, which font is an integral part of the description in this regard. The exhaust gas 11 still has a temperature of some 100 ° C, and this waste heat potential can be used in a known per se and not shown here way. The shaft power output of the turbines 6 and 10 serves to drive the compressor 1 and the generator 13. The generator 13 generates thereby an electrical power P_ACT, A useful power signal is in a first controller 14 with a desired power P_SET compared. From the control deviation P_SET-P_ACT becomes a fuel quantity manipulated variable Y_FUEL formed, which acts on a fuel quantity actuator 15, and thus controls the entire fuel supply to the combustion chambers 4, 8 of the gas turbine group. Two actuators 16 and 17 accomplish the distribution of the total amount of fuel to the two combustion chambers 4 and 8.

0026The criteria according to which this fuel quantity distribution generally occurs are described in detail elsewhere. According to the invention, a sensor S for determining the fuel gas properties X is in the gas supply line_G arranged. From the fuel properties X_G 19 manipulated variables Y are in a function block_EV, Y_SEV, and Y_ST educated. The manipulated variable Y_EV acts on the actuator 16, and thus controls the amount of fuel ṁ_EV the first combustion chamber 4. The manipulated variable Y_SEV acts on the actuator 17 and thus controls the amount of fuel ṁ_SEV the second combustion chamber 8. The manipulated variable Y_ST acts on an actuator 18, which has a mass flow ṁ_ST inert medium, for example steam, zumisst to the first combustion chamber 4. Such a steam injection into the combustion chamber is used, for example, for emission control as prior art familiar to the person skilled in the art. According to the invention, the following control sequence takes place: In a first operating state, the gas turbine group is adjusted to its desired power. The total amount of fuel is adjusted via the actuator 15. By means of the actuators 16 and 17, the distribution of the fuel to the two combustion chambers 4 and 8 takes place in accordance with operating concepts described in detail in other places. The measuring device S measures the fuel properties X continuously or quasi-continuously and almost without time delay_G, in particular the content of higher-value saturated hydrocarbons having 2 or more carbon atoms, the so-called C.₂₊Alkanes or saturated NMCH. If the content of C₂₊Alkanes in the fuel increases, increases the ignitability of the fuel and thus the risk of flashback, especially in a combustion chamber of the self-igniting type. Therefore, for a measured increase, the C₂₊-alkane concentration in the fuel gas over the manipulated variables Y_EV and Y_SEV to the fuel split on the two combustion chambers 4 and 8 intervened, such that the fuel mass flow ṁ_SEV the second combustion chamber is reduced and the fuel mass flow ṁ_EV the first combustion chamber 4 is increased in the same amount. The risk of flashback in the second combustion chamber 8 is thus eliminated. Depending on the operating state but now increases the risk of flashback in the first combustion chamber 4. Therefore, via the manipulated variable Y_ST the actuator 18 is opened, and it is a steam amount ṁ_ST introduced into the first combustion chamber 4, whereby here the higher ignitability of the fuel gas is taken into account. If the C₂₊-Alkan content of the fuel gas exceeds a threshold is further intervened advantageously not shown, the skilled person but familiar way to the protective systems of the gas turbine group, for example, by the power setpoint P_SET is automatically reduced. Furthermore, when a further limit value is exceeded, an emergency shutdown of the gas turbine group can take place.

0027<figref idrefs="f0002">FIG. 2</figref> shows a first burner for a gas turbine group one <patcit id="pcit0025" dnum="WO0196785A"><text>WO 01/96785</text></patcit> known type in connection with an inventive operating method. The burner 20 includes a cylindrical swirl generator 21 and a conical inner body 22. Further, the burner has two different groups of independently fuel-pressurized fuel gas ports 23 and 25 which are fueled by separate fuel gas ports 24 and 26. The metering of fuel to the fuel gas openings 23 and 25 is effected by two actuators 27 and 28. Their supply lines branch off from a common fuel gas supply line, in which a measuring device S for determining the fuel gas properties X_G is arranged. In a functional block 29, starting from the fuel properties X_G Actuating variables Y₁ and Y₂ formed, which act on the actuators 27 and 28. During operation of the illustrated burner in a combustion chamber of a gas turbine group, the actuators 27 and 28 are driven according to specific criteria so as to achieve a respectively favorable distribution of the fuel quantity to the groups of fuel gas openings 23 and 25. The sensor S continuously determines the fuel gas properties X_G and with appropriate changes, the actuators 27 and 28 are intervened to suitably change the fuel distribution within the burner.

0028<figref idrefs="f0002">FIG. 3</figref> shows another one <patcit id="pcit0026" dnum="WO0196185A"><text>WO 01/96185</text></patcit> known burner type. The burner 20 has a conical swirl generator 21, as shown in<patcit id="pcit0027" dnum="EP321809A"><text>EP 321 809</text></patcit> has become known. The burner has two groups 23 and 25 of fuel gas openings. Via the supply lines 24 and 26 with the actuators 27 and 28, the groups can be acted upon independently of each other with fuel gas. Upstream of the actuators 27 and 28 branch off the connections from a common gas supply line. The illustrated burner further includes a variable central axial air supply, as shown<patcit id="pcit0028" dnum="EP1199516A"><text>EP 1 199 516</text></patcit> has become known. In the gas supply line, a measuring device S is arranged, which determines the fuel gas properties and delivers them to the unit 29. When operating within the combustor of a gas turbine group, the fuel quantity distribution to the groups 23 and 25 as well as the axial air flow are suitably preselected. With changes in the combustion gas properties, depending on the measured fuel gas properties X_G via the manipulated variables Y₁ and Y₂ to the fuel distribution and the manipulated variable Y_L influenced on the axial air flow. In particular, with increasing content of C₂₊Alkanes via the manipulated variable Y_L the central Axialluftströmung be reinforced. Thus, the flame stabilization continues downstream of the burner mouth, and the risk of flashback is avoided.

0029<figref idrefs="f0003">FIG. 4</figref> shows one <patcit id="pcit0029" dnum="WO0012936A"><text>WO 00/12936</text></patcit> known burner. This has two groups of fuel gas openings 35 and 38, which via the annular channels 36 and 37, the leads 39 and 41, and the actuators 40 and 42 are independently acted upon with fuel. It follows, analogous to the above examples, a determination of the fuel gas properties X_G, and depending on this, an effect on the fuel distribution on the groups of fuel gas openings 35 and 38 in analogy to the procedure described above.

0030In <figref idrefs="f0004">FIG. 5</figref> is a section of a multi-burner system of a combustion chamber of a gas turbine group shown. The burner 51 is connected to a ring line 52. Fuel gas openings for the premixing operation of the burner will be spiked via this ring line. The burners 61, 62, 63, 64, 65 are connected to fuel lines 66 and 67. Through the ring line 66, first groups of fuel gas openings of the burners 61, 62, 63, 64, 65 are supplied with fuel gas, which are designed, for example, for the injection of gas for premix combustion. Through the ring line 67 further fuel gas openings of the burner 61, 62, 63, 64, 65 are supplied with fuel gas, which are formed, for example, for introducing a combustible gas to be burned in a diffusion combustion mode. The ring lines in turn are connected to a common gas supply. Actuators can be used to independently set the fuel gas mass flows which flow to the individual ring lines and the burners or burner groups or fuel gas openings assigned to them. Such an operating concept is known, for example, from the gas turbine GT13E2 of the applicant, wherein the distribution of the fuel mass flows to the ring lines is substantially performance-dependent. According to the invention, a sensor S for determining the fuel gas properties is X. Such an operating concept is known, for example, from the gas turbine GT13E2 of the applicant, wherein the distribution of the fuel mass flows to the ring lines is substantially performance-dependent. According to the invention, a sensor S for determining the fuel gas properties is X. Such an operating concept is known, for example, from the gas turbine GT13E2 of the applicant, wherein the distribution of the fuel mass flows to the ring lines is substantially performance-dependent. According to the invention, a sensor S for determining the fuel gas properties is X._G arranged in the common fuel gas line. From the fuel gas properties X_G are manipulated variables Y₁, Y₂, and Y₃ formed, which act on the fuel quantity actuators of the ring lines. In this way, in turn can be intervened in a change in the fuel gas properties on the distribution of the fuel within the burner system.

0031<figref idrefs="f0005">FIG. 6</figref> Finally shows a non-inventive gas turbine group whose function does not need to be further explained in the light of the above statements. A fuel quantity regulator 14 regulates via the fuel quantity manipulated variable Y_FUEL and the fuel quantity actuator 15 sets the fuel mass flow to the combustion chamber 4 so that the control deviation of the power, P_SET-P_ACT is just settled and so disappears. In the fuel gas line is a measuring device S for determining the fuel gas properties X._G arranged. Depending on the determined values, a manipulated variable Y_ST formed, which acts on the position of the actuator 18. This in turn determines an inert mass flow ṁ_ST which is added to the fuel gas upstream of the introduction into the combustion chamber 4. If now, for example, the NMCH content of the fuel gas increases, and / or its calorific value, at this point steam or other inert medium is mixed in order to reduce the ignitability or the calorific value of the gas again. It should be emphasized that this introduction of inert media is controlled and does not affect measuring point S. This fundamentally differentiates the method according to the invention from, for example, the closed-loop control of a gas mixing station. While the latter works comparatively sluggishly, the procedure according to the invention is able to react with almost no time delay, since the measuring point is arranged upstream of the media admixing. A change in the fuel gas properties is therefore registered a period of time before they take effect in the combustion chamber. However, since the location of the inert media mixture is located substantially closer to the combustion chamber, the time until the intervention becomes effective is small. Thus, the process is much better suited to initiate countermeasures against impending machine damage due to the changed composition of the fuel gas.

0032Of course, the mentioned embodiments can cover only a small part of the invention characterized in the claims. In particular, the illustrated variants of the method can be used in a variety of meaningful combinations. It would also be possible to combine the measured fuel properties with pulsation and / or emission measured values, measured flame positions, material temperatures and the like to form the aforementioned control variables. The skilled person opens up in the light of the above statements without inventive step a variety of possible and each machine-specific process variants to be selected.

LIST OF REFERENCE NUMBERS

0033<dl id="dl0001" compact="compact"><dt>1</dt><dd>compressor</dd><dt>2</dt><dd>intake</dd><dt>3</dt><dd>compressed air, combustion air</dd><dt>4</dt><dd>combustion chamber</dd><dt>5</dt><dd>cocked flue gas</dd><dt>6</dt><dd>turbine</dd><dt>7</dt><dd>partially expanded flue gas</dd><dt>8th</dt><dd>combustion chamber</dd><dt>9</dt><dd>reheated flue gas</dd><dt>10</dt><dd>turbine</dd><dt>11</dt><dd>exhaust</dd><dt>12</dt><dd>wave</dd><dt>13</dt><dd>generator</dd><dt>14</dt><dd>regulator</dd><dt>15</dt><dd>actuator</dd><dt>16</dt><dd>actuator</dd><dt>17</dt><dd>actuator</dd><dt>18</dt><dd>actuator</dd><dt>19</dt><dd>function block</dd><dt>20</dt><dd>burner</dd><dt>21</dt><dd>swirl generator</dd><dt>22</dt><dd>inner body</dd><dt>23</dt><dd>Group of fuel gas openings</dd><dt>24</dt><dd>Fuel gas supply</dd><dt>25</dt><dd>Group of fuel gas openings</dd><dt>26</dt><dd>Fuel gas supply</dd><dt>27</dt><dd>actuator</dd><dt>28</dt><dd>actuator</dd><dt>29</dt><dd>function block</dd><dt>30</dt><dd>burner</dd><dt>31</dt><dd>Brenner inner body</dd><dt>32</dt><dd>Burner outer casing</dd><dt>33</dt><dd>Brenner annulus</dd><dt>34</dt><dd>Combustion air guide vane, swirl generator</dd><dt>35</dt><dd>Fuel gas openings</dd><dt>36</dt><dd>Fuel gas ring line</dd><dt>37</dt><dd>Fuel gas annulus</dd></dl><dl id="dl0002" compact="compact"><dt>38</dt><dd>Fuel gas openings</dd><dt>39</dt><dd>Fuel gas line</dd><dt>40</dt><dd>actuator</dd><dt>41</dt><dd>Fuel gas line</dd><dt>42</dt><dd>actuator</dd><dt>51</dt><dd>burner</dd><dt>52</dt><dd>Fuel gas ring line</dd><dt>61</dt><dd>burner</dd><dt>62</dt><dd>burner</dd><dt>63</dt><dd>burner</dd><dt>64</dt><dd>burner</dd><dt>65</dt><dd>burner</dd><dt>66</dt><dd>Fuel gas ring line</dd><dt>67</dt><dd>Fuel gas ring line</dd><dt>m '_EV</dt><dd>Fuel gas mass flow</dd><dt>m '_SEV</dt><dd>Fuel gas mass flow</dd><dt>m '_G</dt><dd>Fuel gas mass flow</dd><dt>m '_ST</dt><dd>Inert media mass flow, steam mass flow</dd><dt>P_ACT</dt><dd>Net power</dd><dt>P_SET</dt><dd>Target performance</dd><dt>S</dt><dd>Measuring device for fuel gas properties</dd><dt>X_G</dt><dd>Measurement signal for combustion gas properties</dd><dt>Y₁</dt><dd>manipulated variable</dd><dt>Y₂</dt><dd>manipulated variable</dd><dt>Y₃</dt><dd>manipulated variable</dd><dt>Y_FUEL</dt><dd>Fuel quantity control variable</dd><dt>Y_EV</dt><dd>manipulated variable</dd><dt>Y_SEV</dt><dd>manipulated variable</dd><dt>Y_ST</dt><dd>manipulated variable</dd></dl>