DE10392915B4 - Method for controlling the introduction of inert media into a combustion chamber - Google Patents

Abstract

Method for controlling the introduction of inert media into the combustion zone of a combustion chamber in a closed loop in which the ratio of inert medium mass flow introduced (M) to the fuel mass flow (M) is regulated, which ratio is referred to as omega (Ω), wherein in a first method step, the inert medium mass flow for a base value of omega (Ω) determined as a function of a performance parameter (P) is characterized by the continuous repetition of a control sequence, which comprises the following steps: determining the current omega (Ω) as Actual omega; - detection of combustion pulsation readings (P); - evaluation of pulsation readings; - determination of a pulsation characteristic (P); - determination of a control deviation from the determined pulsation characteristic and a setpoint of the pulsation characteristic; - determination of an omega deviation (ΔΩ). as a function of the control deviation, - change of the actual omega is the Omega deviation by appropriate variation of the inertial mass flow, - as a function of the performance characteristic (P) a lower (Ω) and an upper (Ω) limit for the omega (Ω) to be set and the change in the current omega does not exceed the upper limit and the lower limit is not exceeded.

Description

Technical area

The present invention relates to a method for controlling the introduction of inert media, in particular water or steam, into the combustion zone of a combustion chamber. It further relates to a device which allows operation of the method.

State of the art

It is known to introduce inert media such as water or steam into combustion zones of combustion chambers, for example gas turbine combustors, to reduce nitrogen oxide production in the combustion zone. According to a conventional method in gas turbines, the mass flow of the inert medium is adjusted relative to the mass flow of the fuel. The ratio of mass flow of inert medium to mass flow of fuel is commonly referred to as omega (Ω). According to the state of the art, a course of the omega over a performance characteristic in tests - this may be the shaft power of the gas turbine, but it is also quite common to refer the shaft power to other sizes, such as the environmental conditions - fixed with the Machine is operated in the future. In a simple firing example, the amount of fuel can be used as a measure of the thermal performance as a performance parameter. That is, the introduction of inert medium is operated in an open timing chain, and is therefore not able to respond to external influences parameters, such as changing environmental conditions and consequent shifts in pressure ratios, different fuel compositions, but also simply aging phenomena of the machine. To compensate for such disturbances, the media feed must be operated in a closed loop. Out EP 0 590 829 A2 It is known to measure the nitrogen oxide emissions of a gas turbine and to use as a guide for an injection of inert media, and thus to regulate omega in the closed loop.

However, both approaches disregard the fact that the injection of inert media in flames certainly also has effects on the combustion stability and thus on the combustion pulsations and thus the combustion chamber pulsations of gas turbine combustion chambers. Of course, the value omega could also be regulated to a pure pulsation optimization, which would tend to be here with high emissions.

EP 0 987 495 A2 describes a method for minimizing thermoacoustic oscillations in gas turbine combustors in which, in addition to the fuel stream of the gas turbine combustor, an inert gas such as nitrogen, carbon dioxide or water vapor, is mixed. By varying the amount of inert gas mixed in, a reduction of the thermoacoustic oscillations can be achieved at the gas turbine. By decreasing the pulsations with controlled addition of inert gas, the emission of NOx is reduced in proportion to the decrease of the pressure oscillation amplitudes.

EP 0 314 112 B1 describes a burner for a gas turbine in which, in operation, by means of a flow control water vapor or water is added controlled. For the flow rate of water or water vapor, a fixed ratio to the flow rate of the fuel for the first burner stage is selected, then then depending on the current amount of fuel, the amount of water is controlled

DE 199 41 917 A1 describes a method for monitoring and control of combustion plants, in which a time-frequency noise amplitude diagram is created once, which detects in particular the ignition, the normal burning process and / or continuous control of an optimally adjusted furnace, the regular operation of the furnace is then acoustically monitored and a frequency-noise amplitude diagram is created during operation based on the acoustic monitoring. An evaluation unit with temporal correlation monitors the data based on the frequency noise amplitude diagram with the data based on the time-frequency noise amplitude diagram for agreement within a predefinable bandwidth and indicates an error when the bandwidth is exceeded.

EP 1 215 382 B1 describes a method for operating a premix burner, in which, depending on the combustion pulsation, an amount of an inert medium, such as water or steam, is deliberately introduced into the reaction zone of the burner in a controlled manner. The control of the amount of inert medium to be introduced can either be done easily in an open timing chain in response to a guide size, e.g. B. the current relative power of the gas turbine, or alternatively in a closed loop to keep pulsations below a maximum permissible value.

Presentation of the invention

The object of the invention is to provide a method and a device of the type mentioned in the introduction, which avoid the disadvantages of the prior art and in particular are able to produce favorable conditions with regard to the combustion pulsations while maintaining predetermined emission limit values.

According to the invention, this object is achieved by the method comprising the features of independent claim 1 and by the device according to claim 8. Particularly advantageous embodiments of the invention are the subject of the dependent claims.

The invention is therefore based on pre-controlling the mass flow of the inert medium, in particular steam or water, in a first step according to the prior art as a function of a performance parameter and the fuel quantity to a base value. The performance parameter may be the useful power of a gas turbine, or its relative power, based on the maximum power at the respective ambient conditions; Of course, further meaningful parameters can be formed, in which the useful power of the gas turbine is received. In a simple firing would be to think, for example, the amount of fuel used as a measure of the thermal performance. In this case, the inert medium mass flow is not usually specified directly, but the ratio of inert medium mass flow to fuel mass flow, which dimensionless quantity is also referred to as omega (Ω); the inert media mass flow is then adjusted to reach the omega setpoint. According to the invention, in addition to the precontrol of the inert medium mass flow, a regulation takes place as a function of measured pulsation values. In practice, it has been shown that, depending on the operating state, even a small change in omega can have a strong effect on combustion pulsations that occur. Therefore, the pulsations are measured, detected and evaluated in a manner known per se. Then, a pulsation characteristic is formed. This could be an RMS sum level over a wide frequency range. However, these can also be amplitudes at well-defined frequencies or in narrow frequency bands. In a preferred embodiment of the invention, in the evaluation by bandpass filtering or by a frequency analysis, amplitudes are determined in at least two narrowly defined frequency ranges, and the amplitude values are subtracted from one another at two frequency ranges; this difference then represents the pulsation characteristic. Of course, these examples are by no means exhaustive. From the thus determined Pulsationskenngröße and a setpoint of Pulsationskenngröße a control deviation is determined. Setpoint and control deviation are not interpreted narrowly here, but for the expert will immediately realize that under the setpoint quite well a priori not known minimum of the pulsation characteristic as a function of omega can be understood, or that the setpoint in this context completely equivalent can also be understood in the sense of a permissible operating range, such that the control deviation is then an exceeding or falling below of limits of the pulsation characteristic. Depending on the control deviation, an omega deviation is determined. The omega deviation can, for example, be stored in a digital memory as a digital characteristic map as a function of the control deviation and the load parameter, or be predetermined by a functional, in particular linear, relationship with the system deviation. Ultimately, from the omega deviation in knowledge of the fuel mass flow, a required change in the inert mass flow can be calculated, which is realized by an intervention on the control mechanisms of the inert medium mass flow, for example, a throttle body.

The core of the invention is therefore to precede the introduction of inert media into the combustion zone of a combustion chamber initially - for example, for nitrogen oxide reduction - in an open timing chain, and further to regulate the Pulsationsoptimierung in a closed loop with a Pulsationskenngröße as a guide.

It proves to be advantageous, according to the invention, in addition to a base value for omega, an upper and a lower omega limit as a function of the performance characteristic. It will then be ensured that the Omega control does not exceed or fall below these limits. This avoids that the omega actual value deviates too far from the omega base value, which can lead to far-reaching, in particular operational, technical problems, for example exceeding permissible emission values.

It also proves to be advantageous if a deadband is implemented in the control, in the sense that a change of omega becomes active only when the control deviation of the pulsation characteristic exceeds a certain threshold. This measure prevents an oversensitive "nervous" intervention of the regulation.

In an advantageous embodiment of the method, which is described in detail in the embodiment, a step is added For the evaluation of the Pulsationsmesswerte a frequency analysis - equivalent to a bandpass filtering - is. In this case, pulsation intensities are calculated in at least two frequency bands together to calculate the Pulsationskenngröße. The term intensity of pulsation is intentionally left vaguely in this context, but clearly expresses that this means a variable quantifying the effect of the pulsations. On the one hand, these may be the amplitudes determined in the frequency bands. Since these can be subject to comparatively high temporal fluctuations, measures for smoothing the time course are advantageously used. One possibility for this is to use a maximum value of the amplitudes occurring in a specific time window. As a result, the pulsation intensity changes only when a higher amplitude occurs or when the maximum value of the amplitudes falls out of the time window. In a further embodiment, the pulsation intensity is in each case set equal to the mean value of the amplitudes occurring in a defined time window before "now". The latter measure is often easier to implement, but has the disadvantage that at high fluctuations quite harmful peaks are considered insufficient. This can be taken into account by the average value being given an additive constant if the temporal fluctuations are very high, in particular the standard deviation of the time-dependent amplitudes exceeds a certain value. If, for example, the additive constant is chosen to be twice the standard deviation, then the pulsation intensity determined in succession is greater than approximately 95% of the pulsation amplitudes, with which peak values are sufficiently covered.

A device suitable for carrying out the method according to the invention comprises means for detecting pulsation measured values, means for detecting the actual omega, means for evaluating the pulsation measured values; Means for calculating the characteristic pulsation characteristic, means for determining the control deviation, means for determining the omega deviation as a function of the control deviation, and means for changing the inert mass flow. By way of example and preferably, a sufficiently well-known measuring amplifier or, if the measured values are already available as current or voltage signals, a corresponding measured value input of a downstream evaluation unit functions as a means for detecting pulsation measured values. Actual omega is generally already provided by a machine controller, for example in the form of a current or voltage signal, possibly also as a digitized measured value. In a further embodiment of the invention, the device receives the mass flow signals of fuel and inert medium from which is calculated in an analog or digital divider Omega. Under means for changing the inert medium mass flow is quite a signal output to understand at which a corresponding control variable for the actuator of the inert medium mass flow is applied.

The device may be fully analog, fully digital, or partially constructed of digital and partially analog components familiar to the skilled artisan as individual components. With knowledge of the invention, the skilled person is also familiar with a multitude of possibilities for selecting suitable components and combining them in a suitable manner, without having to give a detailed and explicit teaching for the construction of such a device; However, the knowledge of the invention itself is essential in order to enable the skilled person to do this. In particular, at least a portion of said means may be implemented in the form of a suitably programmed computer, which programming requires a corresponding computer program product which is further suitably stored on a computer readable medium.

In a preferred embodiment, the means for pulsation evaluation comprise at least two bandpass filters which are in signal connection with the means for detecting the pulsation measurement values on the input side. The means for calculating the Pulsationskenngröße include in a preferred embodiment, a subtractor, which is on the input side with the bandpass filters in signal communication. The means for determining the control deviation advantageously include a subtractor, which has an input side with the means for calculating the pulsation characteristic and a reference value transmitter in signal connection. As a means for determining the omega deviation, in particular analog operational amplifier circuits prove to be suitable, which are on the input side with the means for determining the control deviation, and on the output side represent a functional relationship with the control deviation; Furthermore, an analog or digital memory proves to be suitable, in which the respective omega deviation is stored as a function of the control deviation. In this context, the means for changing the mass of inert medium mass also means an analog or digital signal output to which a signal corresponding to the omega deviation is applied.

list of figures

• 1 eine Gasturbine mit Inertmedien-Einbringung und Steuereinheit;
• 2 ein Beispiel für das Spektrum der Brennkammerpulsationen einer Gasturbine aus 1;
• 3 ein Beispiel für den Verlauf der Amplituden von Brennkammerpulsationen bei zwei ausgewählten Frequenzen f1 und f2 in Abhängigkeit vom Massenstromverhältnis Omega des Inertmediums und des Brennstoffs;
• 4 ein Blockdiagramm eines erfindungsgemäßen Regelkreises;
• 5 eine erste, analoge Ausführungsform eines erfindungsgemäßen Reglers;
• 6 eine zweite, digitale Ausführungsform eines erfindungsgemäßen Reglers;
• 7 einen exemplarischen Verlauf des Regelbereichs des Omega-Reglers in Abhängigkeit von einer Leistungskenngröße.

The invention will be explained in more detail with reference to an embodiment illustrated in the drawing. Show in detail

• 1 a gas turbine with inert media introduction and control unit;
• 2 an example of the spectrum of the combustion chamber pulsations of a gas turbine 1 ;
• 3 an example of the progression of the amplitudes of combustion chamber pulsations at two selected frequencies f1 and f2 as a function of the mass flow ratio Omega of the inert medium and the fuel;
• 4 a block diagram of a control circuit according to the invention;
• 5 a first, analogous embodiment of a regulator according to the invention;
• 6 a second, digital embodiment of a controller according to the invention;
• 7 an exemplary course of the control range of the omega controller as a function of a performance characteristic.

The drawing is highly schematic; elements not directly necessary for the immediate understanding of the invention are omitted.

Way to carry out the invention

In the 1 The gas turbine shown to illustrate the invention consists essentially of compressors 1 , Turbine 2 , as well as combustion chamber 3 , From the compressor 1 delivered air flows under pressure into the combustion chamber 3 and is heated there by burning a fuel. A hot gas gets in the turbine 2 relaxed by delivering a mechanical power, which is used to drive the compressor 1 and one over a wave 4 with the gas turbine coupled generator 5 is being used. To the combustion chamber 3 leads a fuel line 11 which in a frequently encountered embodiment is in operative connection with a fuel distribution system (not shown). In the fuel line 11 there is a fuel control valve 13 and a fuel quantity measuring point 15 , To the combustion chamber continues to lead an inert medium line 12 , via which, for example, water or steam is supplied during operation of the gas turbine, which is within the combustion chamber 3 is introduced into the combustion zone and thus reduces the reduction of the maximum flame temperature, the nitrogen oxide formation. In the inert media management 12 are an actuator 14 and a flow measuring point 16 arranged. At the combustion chamber is a Pulsationsmesseinrichtung 17 arranged for measuring combustion pulsations. Known here among other things, the use of high temperature resistant piezoelectric pressure transducer. Their charge signal is in a charge amplifier 18 in a Pulsationsmesssignal P _BK converted, for example, the time-dependent combustion chamber pressure curve in a frequency range of 10 Hz to a few kHz reproduces. The pulsation measurement is of particular importance for machine monitoring, because the inert-medium injection via the line 12 can lead to an increase in the pulsations to critical values. The machine control 20 In reality, it has a large number of signal inputs and outputs, of which only those essential to the implementation of the invention are shown in the drawing. In this context, the signal inputs mentioned on the one hand are the already mentioned pulsations. Furthermore, a power signal P _EL of the generator, readings AMB a sensor 19 for ambient conditions, ie air temperature, pressure, and humidity, as well as signals M _BS and M _H2O the flow measuring points 15 . 16 the fuel line 11 and the inert medium line, for example, NOx water line 12, to the control device 20 guided. The control device 20 includes an omega controller 210 , Starting from the omega controller 210 is a control signal Y _H2O to the actuator 14 led for the inert medium. From the power signal P _EL and the environmental conditions AMB is preferably a relative power P _REL the gas turbine calculated. In one embodiment of the invention, initially a number of base values for the fuel mass flow-related inert medium mass flow, ie for omega, in dependence on the relative power P _REL established. For this purpose, emissions are measured in test series, and in the case of a number of auxiliary values of the relative power, omega is set in such a way that admissible emission limit values as well as permissible pulsation limit values are complied with. Between these supporting values, the setpoint omega to be set is interpolated. In a conventional approach, compliance with the limit values with the values thus determined for omega is verified in one or more test series, and the gas turbine is operated with these settings. Pulsation readings or also measurement data of an emission operating measuring device are not used for control interventions on the inert medium mass flow, but only to carry out actions such as warnings or even an emergency shutdown when certain limit values are exceeded. However, it is now known that pronounced changes in the ambient conditions, in particular temperature fluctuations, or the operating state of the gas turbine, for example a cold machine immediately after a start, can have a great influence on the pulsation behavior. Not only are summation levels of the pulsations of interest, but also commonly occurring pulsation peaks in narrow frequency ranges, which can be highly damaging due to the pure frequency excitation, especially if they are close to the natural frequency of certain components.

In 2 is an example of a spectrum of combustion chamber pulsations qualitatively. While some of the pulsations are distributed across the spectrum over a broadband spectrum, two frequencies fall f1 and f2 on, in which high amplitudes are observed. The pulsation amplitudes at these frequencies are dependent on the mass flow ratio omega. In the 3 In fact, dependency is often observed in practice: as the proportion of inert medium increases, the amplitude decreases, and at the higher frequency f2 is observed, while at the lower frequency f1 observed amplitude increases. In the interests of a broadband pulsation spectrum, which bundles as little energy as possible in narrow spectral ranges, these countervailing trends provide an optimum for omega, which is to be sought approximately where equal amplitudes occur at both characteristic frequencies. An omega control according to the invention must therefore equal amplitudes for two characteristic frequencies in the illustrated case f1 and f2 adjust the combustion pulsations.

In 4 is a schematic structure of an omega controller 210 shown as a block diagram in more detail. Inside the control unit 20 receives a register 21 an input signal P _REL for the relative gas turbine power, which from the electric generator power P _EL and the ambient conditions AMB has been calculated in a manner known per se. Depending on this input, the register determines 21 a basic omega Ω ₀ , Made of basic Omega and a fuel mass flow signal M _BS , which from the in 4 not shown fuel flow measuring point 15 is delivered, determines the control 211 a manipulated variable Y _H2O for the inert media actuator 14 , This influences the inert media mass flow M _H2O , A calculator 214 determined from fuel mass flow and Inertmedienmassenstrom the actual omega Ω _AKT , The inert media mass flow M _H2O continues to influence those in the combustion chamber 3 ongoing processes. This manifests itself among other things in changed pulsations, which are caused by the measuring probe 17 detected and in the amplifier 18 in a pulsation signal P _BK be implemented. In an evaluation member 212 becomes out of the pulsation signal P _BK by means of suitable and machine-specific to be determined transformations to be controlled, in particular to be optimized, Pulsationskenngröße P _{BK, p} , educated. A regulator 213 determines a control deviation of the pulsation characteristic and determines therefrom an omega deviation ΔΩ , In a summer, the actual omega becomes Ω _AKT and the omega deviation ΔΩ to a new target omega Ω _SHOULD merged, from which the control 211 the inert media control value Y _H2O redetermined. The evaluation element 212 preferably contains means or algorithms which, for example by averaging over a certain time, low-pass filtering of the amplitudes, or determination of a maximum occurring in a certain time interval, temporal smoothing of the course of Pulsationskenngröße. The rule member 213 is advantageously designed so that only then an omega deviation is formed when the deviation exceeds a threshold. Both measures together avoid an overly nervous to unstable behavior of the regulator. The control 211 is advantageously implemented as an integrator and includes a limit to the deviation of the omega to be set from the base omega.

All elements can be fully digital, fully analog, or including both analog and digital elements. In particular, the entire control unit 20 be run with the Omega controller as suitably programmed computer.

5 shows a first embodiment of the Auswertegliedes 212 with fully analogous construction. The pulsation signal P _BK becomes two bandpasses BP1 and BP2, which are the pulsation signals at the frequencies f1 and f2 filter out the overall signal. Two limbs RMS 1 and RMS2 form the RMS rms values of the alternating components determined in a manner known per se. The RMS signals are in two low passes LP1 and LP2 processed so that extreme transients of the signals, which could endanger the stability of the control loop, are turned off. In the case shown, it is further assumed that the frequency f2 occurring amplitudes is subjected to very strong fluctuations, so that by the low-pass filtering in LP2 Pulsation peaks are no longer adequately weighted. The determined value is therefore given an additive constant K superimposed. By subtraction of the two determined values at the frequencies f1 and f2 becomes the pulsation characteristic P _{BK, p} calculated. The rule member 213 , which is designed as a proportional element with dead band, then provides as output an omega deviation ΔΩ when the Pulsationskenngröße exceeds the threshold value of the dead band. If the at the frequency f2 certain amplitude is greater than that determined at f1, omega is increased, which is in accordance with the in 3 characteristic shown the amplitude at the frequency f2 reduced. Conversely, if the amplitude at f1 is greater than that at f2, omega is reduced, resulting in a smaller amplitude at f1.

In 6 is a further preferred embodiment of the Auswertegliedes 212 from digital Components shown. The pulsation signal P _BK is in an analog-to-digital converter A / D amplitude and time discretized. The digitized signal is in a frequency analyzer FFT subjected to a frequency analysis. Amplitude values at two frequencies f1 and f2 are sent to fifo memory FIFO1 and FIFO 2 passed on, and there a number of temporally successive amplitude values are stored. Suitable agents MAX1 and MAX2 determine the highest amplitude value stored in a FIFO. In addition, the pulsation characteristic is also here by a (digital) subtractor P _{BK, p} formed, and it becomes the rule member 213 the omega deviation is determined.

7 finally shows an advantageously implemented limit of the control range of the omega controller 210 , Base Omega Ω ₀ is dependent on the relative power P _REL specified. With advantage is how in 7 shown, the control range of the omega controller up and down by the limits Ω _MIN and Ω _MAX limited. This avoids excessive deviations from the base Omega, which could lead to inadmissible emission levels or to flame extinguishment.

Further embodiments of the invention characterized in the claims will become apparent to those skilled in the light of these statements by itself.

LIST OF REFERENCE NUMBERS

1

compressor

2

turbine

3

combustion chamber

4

wave

5

generator

11

fuel line

12

Inert media line, NOx-water line

13

Fuel control valve

14

Inert media-actuator

15

Fuel quantity measuring point, fuel flow measuring point

16

Inert media flow measurement point

17

Pulsationsmesseinrichtung

18

charge amplifier

19

Environmental sensor

20

Machine control, control device

21

register

210

Omega-regulator

211

control

212

evaluation element

213

control element

214

computing element

AMB

Ambient conditions (temperature, pressure, humidity)

A / D

Analog to digital converter

BP1, BP2

bandpass

FFT

frequency analyzer

FIFO1, FIFO2

FIFO memory

K

additive constant

LP1, LP2

lowpass

M _BS

Fuel mass flow signal

M _H2O

Inert media mass flow

MAX1, MAX2

Maximum value determination limbs

P _BK

pulsation

P _{BK, p}

Pulsationskenngröße

P _EL

power signal

P _REL

Performance Characteristic, Relative Gas Turbine Performance

RMS1, RMS2

RMS RMS computation section

Y _H2O

Inert media control signal, manipulated variable

f1, f2

characteristic frequencies of the pulsation spectrum

Ω

Omega: Ratio of inert mass flow to fuel mass flow

Ω ₀

Basic Omega, performance-dependent pre-controlled Omega value

Ω _AKT

Is Omega

Ω _SHOULD

Target Omega

Ω _MIN , Ω _MAX

Omega-limit

ΔΩ

Omega-deviation

Claims (12)

A method of controlling the introduction of inert media into the combustion zone of a closed loop combustion chamber in which the ratio of inert media mass flow introduced (M _H2O ) to fuel mass flow (M _BS ) is controlled, which ratio is referred to as omega (Ω) in which, in a first method step, the mass inertia mass flow is precontrolled for a base value of omega (Ω ₀ ) determined as a function of a performance parameter (P _REL ), characterized by the continuous repetition of a control sequence which comprises the following steps: determining the current omega (Ω _AKT ) as actual omega; - detection of combustion pulsation measurements (P _BK ); - evaluation of pulsation measured values; - determination of a pulsation characteristic (P _{BK, S} ); - Determination of a control deviation from the determined Pulsationskenngröße and a target value of Pulsationskenngröße; - Determination of an omega deviation (ΔΩ) as a function of the control deviation; - Change of the current omega by the omega deviation by corresponding variation of the inert media mass flow; - as a function of the performance characteristic (P _REL ), a lower (Ω _MIN ) and an upper (Ω _MAX ) limit for the adjusted omega (Ω _SOLL ) are fixed and when changing the current omega does not exceed the upper limit and the lower limit not fallen below. Method according to Claim 1 , characterized in that a dead band for the control deviation of the Pulsationskenngröße (P _{BK, S} ) is predetermined and takes place at a deviation of the Pulsationskenngröße within this dead band no change in the current omega. Method according to one of the preceding claims, characterized in that a step of evaluating the Pulsationsmesswerte a frequency analysis (FFT) or a bandpass filtering (BP1, BP2) and that are calculated to calculate the Pulsationskenngröße pulsation intensities in at least two frequency bands (f1, f2) with each other , Method according to Claim 3 , characterized in that the pulsation intensity is set in a frequency band equal to the determined in the frequency analysis or in the bandpass filtering amplitude in the frequency band. Method according to Claim 3 , characterized in that the pulsation intensity is set in a frequency band equal to the maximum of the time-dependent amplitudes determined in the frequency analysis within a certain time interval in the frequency band. Method according to Claim 3 , characterized in that the pulsation intensity is set in a frequency band equal to a time average of the amplitudes or maxima of the amplitudes, which were determined in the frequency analysis in the frequency band. Method according to Claim 6 , characterized in that the pulsation intensity in a frequency range before the offset with the pulsation intensities in other frequency ranges is offset with an additive constant when the standard deviation of the time-dependent pulsation intensities exceeds a predetermined limit. Apparatus for carrying out the method according to one of Claims 1 to 7 comprising: means for detecting pulsation measurements (18); Means for determining the actual omega (214); Means for evaluating the pulsation readings; Means for calculating the characteristic pulsation characteristic (212); Means for determining the control deviation; Means for determining the omega deviation as a function of the control deviation (213); Means for changing the inert media mass flow. Device after Claim 8 , characterized in that the means for evaluating the pulsation measured values comprise at least two bandpass filters (BP1, BP2) which are in signal connection with the means for detecting the pulsation measured values (18) on the input side. Device after Claim 9 , characterized in that the means for calculating the characteristic Pulsationskenngröße include at least one difference former, which is on the input side with at least two bandpass filters in signal communication. Device according to one of Claims 8 to 10 , characterized in that the means for determining the control deviation include at least one difference former, which are on the input side with a reference value transmitter and the means for calculating the characteristic Pulsationskenngröße in signal communication. Device according to one of Claims 8 to 11 , characterized in that at least part of the means are realized by a suitably programmed computer.

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