JPS61132729A - Gas turbine combustion control equipment - Google Patents

Abstract

PURPOSE:To avoid abnormal vibration of a gas turbine due to combustion vibration by dividing fuel nozzles into plural groups and fixing fuel quantity adjustment valves and fuel volume detectors to fuel pipes of respective groups. CONSTITUTION:Of fuel nozzles 13 of a combustion chamber 10, fuel nozzles adjoining alternately 13a, c, e, g are connected with a fuel pipe 30, and the remaining fuel nozzles 13b, d, f, h are connected with a fuel pipe 40. To the fuel pipes 30, 40, fuel quantity adjustment valves 31, 41 and fuel volume detectors 32, 42 are fixed. The fuel quantity adjustment valves 31, 41 are adjusted on the basis of output from a fuel-air ratio discriminator 65. As this makes it possible to adjust the fuel flow volume of respective groups separately, abnormal vibration die to combustion vibration can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a gas turbine combustion control device that prevents the occurrence of combustion oscillation phenomena.

[Technical background of the invention]

A gas turbine includes a turbine section, a combustor that sends high-temperature combustion gas to the turbine section, a compressor that sends compressed air to the combustor, a motive rock for starting, and the like.

FIG. 2 shows an example of a stationary gas turbine equipped with eight combustors.
The rotating shaft 4 of the turbine is directly connected, and when the turbine rotates,
Air is sucked into the casing 7 from the suction section 6 by multistage vanes 5 installed on the outer periphery of the rotating shaft 4 . The sucked air is gradually compressed as it passes through the blades 4 of each stage, and is sent into the combustors 108 to 10h as high-pressure compressed air 8.

Each combustor is composed of an outer cylinder 11, an inner cylinder 12 built into the outer cylinder 11, and a fuel nozzle 13 provided at the tip of the inner cylinder 12.
The rear end side of the inner cylinder 12 is connected to the first stage nozzle 20 of the turbine section 1 via the transition piece 14 .

Although only one combustor 10a is shown in longitudinal section in FIG. 2, the configurations of the other combustors 10b to 10h are also the same.

The compressed air sent into the outer cylinder 11 of the combustion 2S10a passes through the through hole provided in the side wall near the tip of the inner cylinder 12 and flows into the C inner cylinder 12.
The fuel flows into the fuel tank, mixes with the fuel sent from the fuel nozzle 13, and burns it.

The high-temperature, high-pressure combustion gas generated by this combustion passes through the transition piece 14 and the first-stage nozzle 20, and is blown onto the first-stage rotor blade 21 fixed to the turbine rotating shaft 2. The flow flows down the rotor blades in sequence, converting thermal energy into rotational energy, and gradually cooling the rotor blades to 500℃ while giving rotational force to each stage rotor blade.
It is discharged as exhaust gas at about 600°C.

As described above, gas turbines are used for a variety of purposes because they can efficiently perform high-temperature, high-pressure combustion reactions in a relatively small-capacity combustor, but it is difficult to create a low-pollution combustor. Very advanced technology is required.

Moreover, even if the combustor is designed and manufactured perfectly,
Vibrations caused by combustion reactions may occur in the combustor, such as during high-load operation of the turbine.

[Problems with background technology]

The vibrations caused by the combustion reaction described above are called combustion vibrations, and although their existence has been recognized for a long time, no appropriate countermeasures have been taken in conventional gas turbines.

Therefore, when a combustion vibration phenomenon occurs in the gas turbine combustor, the transition piece in the combustor and the
There was a drawback that repeated loads exceeding the design value were applied to parts such as the stage stationary vanes, which were exposed to the highest temperatures and had the lowest design margin, and these components were damaged within a relatively short period of time.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a gas turbine combustion control device that can eliminate the above-mentioned drawbacks in the background art and avoid abnormal vibrations caused by combustion vibrations.

[Summary of the invention]

In order to achieve the above-mentioned object, the gas turbine combustion control device of the present invention provides a gas turbine equipped with a turbine section, a combustor that sends combustion gas to the turbine section, and a compressor that sends compressed air to the combustor. The fuel nozzles of the combustor are divided into a plurality of groups, and a fuel flow regulating valve and a fuel flow rate detector are provided in each of the fuel pipes that feed fuel to the eight fuel nozzles. m'JA
This is characterized in that combustion oscillations are prevented by shifting the opening degree of the valve adjustment upward on one side and downward on the other.

Next, the operating principle of the present invention will be explained.

To elucidate the above-mentioned combustion oscillation phenomenon, many researchers have been conducting research in various fields. This combustion swing J is extremely complicated, and there are still many parts that remain unexplained even today, but according to the experiments of the inventors such as Wood, the pressure fluctuation inside the combustor due to combustion vibration is shown in Figure 3. As shown, it was found that the fuel-air ratio greatly depends on the fuel-air ratio, and that the fuel-air ratio in particular becomes abnormally large within the range B in the figure. Furthermore, when the fuel-air ratio is increased, the pressure fluctuation frequency within the combustor gradually decreases as shown by the solid line in Figure 4, but this solid line and the dotted line E indicate It has been found that the abnormal vibration shown at 8 in FIG. 3 occurs at the fuel-air ratio near the intersection point due to the air column frequency.

This is because if the fuel-air ratio is set within the range A or C in Figure 3, abnormal vibrations due to combustion vibration can be avoided, and even in the event of abnormal vibration, the fuel-air ratio is set within the range B in Figure 3. From A
Alternatively, it means that abnormal vibration can be eliminated by shifting to the C range.

The present invention has been made based on this knowledge, and consists of dividing the maximum number of fuel nozzles of a combustor installed in a gas turbine into a plurality of groups, and dividing the fuel nozzles of each group into ranges A or C in FIG.
It is configured to operate at a fuel-air ratio of .

(Embodiments of the invention) Next, the present invention will be described in detail with reference to FIG.

The compressor 3 in FIG. 1 is shown in a cross section taken along the knee I line in FIG.
~10h are arranged and fixed at equal intervals in the circumferential direction.

These combustors are equipped with fuel nozzles 13a to 13h as explained with reference to FIG. The high-temperature, high-pressure gas thus generated is sent to the turbine section, applying rotational force to the turbine.

The fuel nozzles 13a, 13C, 13e, and 13G of the combustors 10a, 10c, 10e, and 10g that are adjacent to each other at the back of the eight combustors 10a to 10h are connected to branch pipes 3, respectively.
It is connected to the fuel pipe 30 through 0a, 30c, 30e, 30g, and the remaining combustors 10b, 10d, 10f
, 1Qh fuel nozzle 13b.

14d, 13f, and 13h are branch pipes 40b and 4, respectively.
It is connected to the fuel pipe 40 through 0d, 40f, and 40h.

These fuel pipes 30 and 40 are provided with fuel flow regulating valves 31 and 41 and a fuel flow layer detector 32 on the upstream side of the branch pipe, respectively.
．． 42 is inserted, and further merges on the upstream side,
It is connected to a fuel supply device 51 via a fuel main pipe 50.

The output signal of the fuel leakage detector 32.42 is the leakage projector 60.
The output signal 61A of the adder 61 is input to the fuel/air ratio setter 62.

This fuel-air ratio setting device 62 is necessary based on the fuel flow ω signal 61A input from the adder 61, the combustion air flow m signal 63A sent to the combustor, and the gas turbine output stage straightening signal 64A. The fuel-air ratio is set and the set value signal 62A is outputted to the fuel-air ratio discriminator 65.

The output signal 65A of the fuel-air ratio discriminator 65 is sent to the valve opening setting device 66.
The setting signal 66 is guided by the setting device 66 and output from the setting device 66.
A and 66B adjust the opening degree of the flow m adjustment valve 31°41.

In the apparatus of the present invention configured as described above, the fuel-air ratio discriminator 65 is connected to the combustors 10a to 1 as explained with reference to FIG.
A fuel/air ratio range B in which pressure fluctuation within 0h is abnormally increased is stored.

During normal operation of the gas turbine, the output signal 62△ of the fuel-air ratio setting device 62 is input as is to the valve opening setting device 66, and the openings of the zero flow adjustment valves 31 and 41 are controlled to be the same.
When the fuel-air ratio setter 62 sets the fuel-air ratio in the range B in FIG. 41 to set different opening degrees. That is, the fuel-air ratio is B17 in Figure 3.
) range, the first group combustors 10a, 10c, 10e, 10g connected to the flow rate adjustment valve 31 have a fuel-air ratio in the range shown in FIG. 2nd group combustor 10b, 10d.

The opening degrees of the flow rate regulating valves 31 and 41 are adjusted so that 10f and 10h have the fuel-air ratio in range C in FIG. In this case, the opening degrees of both valves are adjusted so that the total fuel-air ratio of the first and second group combustors becomes equal to the set value of the fuel-air ratio setting device 62.

As mentioned above, according to one embodiment of the present invention, the fuel nozzles 138-13h of the combustors 108-10h of the gas turbine
The combustor is divided into two groups, and the opening of the flow adjustment valve that adjusts the flow rate of fuel sent to each group is adjusted to a fuel-air ratio that does not cause combustion vibrations. can be prevented from being damaged by

However, the above-mentioned combustion phenomenon does not always occur when the fuel-air ratio is in range B in Figure 3, and it is thought that it occurs due to a complex interaction of the gas turbine output setting and other factors. .

Considering this point, when the fuel-air ratio setting value is set within the range shown in Figure 3B, the opening degree of the flow regulating valve is controlled so that the fuel-air ratio of each group combustor always shifts upward or downward. do not have to.

Therefore, in the present invention, an imaging detector or a pressure transducer (not shown) is installed in the gas turbine or each combustor, and the output signals of these detectors or transducers are used to determine the fuel-air ratio shown in FIG. If the fuel-air ratio discriminator is configured so that the shift signal is output to each flow σ adjustment valve only when combustion oscillation or its precursor occurs, fuel efficiency can be reduced. However, various adverse effects associated with combustion vibration can be avoided.

Although the above-mentioned embodiment shows an example in which the present invention is applied to a gas turbine of the type in which eight combustors 10a to 10h are arranged on the circumference, the present invention is not limited to this. The present invention can also be applied to a combustor with a single combustion chamber and a plurality of fuel nozzles and a swirler nozzle outside the fuel nozzle. FIG. 5 shows an embodiment of this kind,
The explanation of the parts common to FIG. 1 will be omitted, and the different parts will be explained as follows. That is, in this example, the fuel nozzle 13a of 41[fa] is connected to the annular combustion chamber.
13b, 13c, and 13d are arranged, and a swirler nozzle for combustion air is arranged concentrically outside each nozzle.

On the other hand, the compressed air from the compression 1170 is transferred to the branch pipes 71a and 7
It is supplied into the TE-shaped combustion T through 1b, 71c, and 71d. These branch pipes 71a.

71b, 71c, 71d have flow rate adjustment nozzles 72a, 7
．． 2b, 72c, 72d and the flow is detected by the detector 73a, A3.
b, 73c, and 73d are incorporated.

These flow rate detectors 73a, 73b, 73c.

The output signal from 73d is sent to the adder 7 via the flow rate@calculator 74.
5, and an output signal 63A from the adder 75 is input to the fuel/air ratio setter 62.

Further, the output signal 65B from the fuel-air ratio discriminator 65 is guided to a nozzle opening degree setting device 76, and output signals 77a, 77b, 77 from this setting device 76 are used to adjust the nozzle spacing.
c, 77cH; t Sole flow mother adjustment nozzles 72a, 72
b, 72c, and 72d to set a predetermined valve opening degree.

In the embodiment configured as described above, during normal operation of the gas turbine, the valve opening setting device 66 and the nozzle opening setting device 76 receive the output signals 65A, 65B of the fuel/air ratio setting device 65.
is input as is), and the opening degrees of the flow rate adjustment valves 31 and 41 and the opening degrees of the flow rate adjustment nozzles 72a, 72b, 72c, and 72d are controlled in the same way, and the range of A or C of the fuel-air ratio in FIG. Driven within. On the other hand, the fuel-air ratio setting device 6
2 sets the fuel-air ratio in range B in FIG. Issue a command. That is, in this case, the 11th! The flow regulating valves 31 and 32 and the flow rate are adjusted so that the fuel nozzles 13a and 13G of the second group have a fuel-air ratio in range A in FIG. 3, and the second group of fuel nozzles 13b and 13d have an air-fuel ratio in range C in FIG. The opening degrees of the regulating valves 72a, 72c and 72b, 72d are adjusted. Even in such an embodiment, the same effects as in the above embodiment can be obtained. It goes without saying that the air G may be adjusted by adjusting the opening degree of the swirler nozzle.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to prevent low combustion in the combustor, so that various parts of the combustor, especially components used under the harshest conditions such as the transition piece and the first stage nozzle of the turbine, can be prevented. can be prevented from deteriorating or breaking due to vibration.

Therefore, the lifespan of each part is extended, the period for window replacement can be extended, a highly reliable gas turbine can be obtained, and the work associated with parts replacement can be reduced. It is possible to shorten the downtime and turbine downtime, and reduce maintenance costs. Also, since the lotus rotation range is not restricted,
A gas turbine that is easy to use can be obtained.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an embodiment of the device of the present invention, Fig. 2 is a partially longitudinal front view of main parts showing an example of a gas turbine, and Figs. 3 and 4 are graphs for explaining combustion vibration. , FIG. 5 is an explanatory diagram showing another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Turbine part, 2, 4... Rotating shaft, 3... Compressor, 5... Vane, 6... Air intake port, 7... Casing, 8... Compressed air, 10a-10. h...
Combustor, 11...outer cylinder, 12...inner cylinder, 1, 3...
・Fuel nozzle, 14...Transition piece, 20
...1st stage nozzle, 21...turbine! FJI Tsubasa,
30;'40...Fuel pipe, 31.41...Fuel flow rate adjustment valve, 32.42...Fuel flow rate detector, 5o...
・Fuel main pipe, 60...The flow is a calculator. Figure l

Claims (1)

[Claims] 1. In a gas turbine comprising a turbine section, a combustor for feeding combustion gas into the turbine section, and a compressor for feeding compressed air into the combustor, the fuel nozzles of the combustor are arranged in a plurality of groups. A fuel flow rate adjustment valve and a fuel flow rate detector are provided in each of the fuel pipes that feed fuel to the fuel nozzles of each group, and the fuel flow rate adjustment valve is adjusted to different opening degrees based on the output of the fuel-air ratio discriminator. A gas turbine combustion control device configured to allow 2. The fuel-air ratio discriminator determines when the set value signal from the fuel-air ratio setter is within the range that may cause combustion vibration, and sets one fuel adjustment valve to the high opening side. 2. The control device according to claim 1, wherein the control device shifts the other fuel adjustment valve to a lower opening degree side. 3. The fuel-air ratio discriminator is configured to input the output signal of a vibration detector or pressure transducer that detects vibration or pressure of the gas turbine or combustor, and shifts the fuel adjustment valve to a different opening degree. A control device according to claim 1 or 2, characterized in that: 4. Divide the fuel nozzles of the combustor into a plurality of groups, and provide a fuel flow rate adjustment valve for each fuel pipe that feeds fuel to the fuel nozzles of each group, and connect air supply pipes that supply combustion air to the combustor to the corresponding groups. 2. The control device according to claim 1, further comprising an air flow rate adjustment valve for adjusting the amount of air supplied on each group of air supply pipes.