JP2003278560A - Flame-out discrimination method and gas turbine device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-out discrimination method allowing accurate and speedy discrimination of the occurrence of flame-out, and also to provide a gas turbine device. <P>SOLUTION: This flame-out discrimination method is provided with an air-fuel ratio calculation part 31 for calculating an air-fuel ratio of air and fuel in air-fuel mixture, a temperature rise rate calculation part 18 for calculating a temperature rise rate of exhaust gas temperature measured on the downstream side of a combustor, an acceleration calculation part 16 for calculating acceleration of a turbine, and a flame-out discrimination part 18 for discriminating the occurrence of flame-out when the air-fuel ratio calculated by the air-fuel ratio calculation part 31 is below a predetermined reference air-fuel ratio, the temperature rise rate of the exhaust gas temperature calculated by the temperature rise rate calculation part 18 is minus, and the acceleration of the turbine calculated by the acceleration calculation part 16 is minus. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flameout determination method and a gas turbine device, and more particularly to a flameout determination method capable of accurately determining occurrence of flameout during load operation.

[0002]

2. Description of the Related Art A general gas turbine apparatus includes a turbine rotatably mounted via a rotary shaft, a combustor for generating combustion gas, and a fuel adjustment for adjusting a fuel supply amount to the combustor. It is basically composed of a valve, an air compressor for feeding air to the combustor, a generator connected to a rotating shaft, and the like.

In the above structure, the fuel adjusted by the fuel control valve and the air compressed by the air compressor (hereinafter, appropriately referred to as compressed air) are supplied to the combustor,
A mixture of compressed air and fuel is formed in the combustor. Then, in the combustor, the air-fuel mixture is combusted to generate combustion gas, and the combustion gas is supplied to the turbine, whereby the turbine rotates at high speed. As described above, the generator is attached to one end of the rotating shaft, and power is generated by driving the generator with the turbine via the rotating shaft.

Generally, a gas turbine device is provided with a control device for controlling a turbine, and the control of a turbine which is supplied with combustion gas and rotates is performed by this control device. Explaining this control device in detail, for example, the present rotational speed of the turbine is detected and fed back to the calculation unit so that the deviation between the fed back current rotational speed and the preset target rotational speed is minimized. The control unit calculates the control signal. Then, the rotational speed of the turbine is controlled by operating the opening of the fuel control valve based on this control signal.

By the way, in the gas turbine apparatus as described above, a phenomenon called so-called flameout may occur in which the combustion flame suddenly extinguishes while supplying fuel to the combustor. When this frame out happens,
Not only the gas turbine device may stop, but the supplied fuel or air-fuel mixture may fill the inside of the gas turbine device, causing ignition and explosion due to residual heat from the turbine or the like.
Therefore, when a flameout occurs, it is extremely important to promptly detect it and stop the fuel supply.

As a determination factor for determining the occurrence of flameout, the mass ratio (or weight ratio) of air and fuel in the air-fuel mixture, that is, the air-fuel ratio (air fuel ratio,
(Also referred to as A / F). The air-fuel ratio is a mass ratio of air and fuel used for combustion, that is, a mixing ratio, and can be obtained by dividing the flow rate of air per unit time by the flow rate of fuel per unit time. As described above, the air is compressed by the air compressor and sent to the combustor, and the air compressor is driven by the turbine. Therefore, the flow rate of the air is proportional to the rotation speed of the turbine, and Since the flow rate is proportional to the opening of the fuel control valve, the air-fuel ratio can be derived from the rotational speed of the turbine and the opening of the fuel control valve.

When a flameout occurs, the supply of combustion gas is stopped, so that the rotational speed (flow rate of air) of the turbine is decelerated, and feedback control is performed to restore the decelerated rotational speed. Since the fuel flow rate) increases, the air-fuel ratio tends to decrease. Therefore, if the air-fuel ratio assumed when a flame-out occurs is set in advance as a reference air-fuel ratio for determining that a flame-out has occurred, if the air-fuel ratio falls below this reference air-fuel ratio Can be determined to have occurred. Based on this, in the conventional gas turbine device, a method of constantly monitoring changes in the air-fuel ratio and determining that a flameout has occurred when it is detected that this air-fuel ratio falls below a set reference air-fuel ratio Has been adopted.

[0008]

However, in the above-described conventional flameout determination method, it is possible to mistakenly determine that a flameout has occurred when the load (power generation output, etc.) received by the gas turbine device increases. is there.
The state of the gas turbine device in this case will be described with reference to FIG. FIG. 4 is a graph showing changes over time in numerical values when the load on the conventional gas turbine device increases. The exhaust gas temperature indicates the exhaust gas temperature measured by an exhaust gas temperature measuring device installed in the pipe on the downstream side of the combustor.

As shown in FIG. 4, when the load (LOAD) on the gas turbine device increases, the number of revolutions (NR) of the turbine inevitably decreases.
Then, since the fuel supply is increased by the feedback control for increasing the rotation speed, the air-fuel ratio (A / F) is decreased as in the case where the flameout occurs. At the same time, the exhaust gas temperature (Exhaust Gas Temperature, EGT) rises as the fuel supply increases. Then, as shown in FIG. 4, when the increase in the load is large, the air-fuel ratio becomes lower than the above-mentioned reference air-fuel ratio. Therefore, although the flame-out does not actually occur, the flame-out does not occur. Will erroneously determine that

In order to avoid such a problem, in the prior art, as shown in FIG. 4, the problem has been solved by lowering the reference air-fuel ratio which is the criterion for determining the occurrence of flameout, but the reference air-fuel ratio is lowered. This causes the following problems. That is, if the reference air-fuel ratio is set low, the difference between the value of the air-fuel ratio during steady operation (at rated rotation) and the value of the reference air-fuel ratio becomes large, so the air-fuel ratio that decreases when the flame-out actually occurs. It takes time for the fuel ratio to reach the reference air-fuel ratio. Then, the time lag from the occurrence of the actual frame-out to the determination that the frame-out has occurred becomes large. This means that the timing of stopping the fuel supply is delayed, and the above-mentioned accident may occur.

The present invention has been made in view of such conventional problems, and an object thereof is to provide a flameout determination method and a gas turbine apparatus capable of accurately and promptly determining the occurrence of flameout. And

[0012]

In order to solve the above-mentioned problems, the present invention provides a flameout determination method for determining whether or not a flameout has occurred during operation of a gas turbine apparatus. The air-fuel ratio between the fuel and the fuel is below a predetermined reference air-fuel ratio, and the temperature rise rate of the exhaust temperature measured on the downstream side of the combustor that burns the air-fuel mixture is negative, and the turbine acceleration is negative. In some cases, it is determined that a frame-out has occurred. In this case, the air-fuel ratio is based on the rotational speed of the turbine, which is approximately proportional to the amount of air supplied to the combustor, and the opening of a fuel control valve that adjusts the amount of fuel supplied to the combustor. It is preferable to calculate the air-fuel ratio.

Further, the present invention is a gas turbine device for rotating a turbine by burning a mixture of air and fuel in a combustor and supplying combustion gas generated by the combustion to the turbine. An air-fuel ratio calculation unit that calculates an air-fuel ratio between air and fuel in the air-fuel mixture, a temperature increase rate calculation unit that calculates a temperature increase rate of the exhaust temperature measured on the downstream side of the combustor, and an acceleration of the turbine. And an acceleration calculation unit for calculating, the air-fuel ratio calculated by the air-fuel ratio calculation unit is below a predetermined reference air-fuel ratio, and the temperature rise rate of the exhaust temperature calculated by the temperature rise rate calculation unit is negative. And a flameout determination unit that determines that a flameout has occurred when the acceleration of the turbine calculated by the acceleration calculation unit is negative. To. In this case, an air compressor that is driven by the turbine to supply air to the combustor and a fuel control valve that controls the amount of fuel supplied to the combustor are provided, and the air-fuel ratio calculation unit is It is preferable to calculate the air-fuel ratio based on the rotational speed of the turbine and the opening of the fuel control valve.

According to the present invention, it is judged that the frame-out has occurred only when all of the above three judgment criteria are satisfied. Therefore, when the load on the gas turbine device increases and the air-fuel ratio decreases, it is possible to prevent erroneous recognition that a flameout has occurred. Also, since there is no risk of misidentification due to such an increase in load, it is possible to raise the reference air-fuel ratio, which is the criterion for determining the occurrence of flameout, and as a result, if a flameout actually occurs, this can be quickly Can be detected.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a gas turbine device according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the overall configuration of a gas turbine device according to this embodiment.

As shown in FIG. 1, the gas turbine device in this embodiment adjusts a turbine 1, a combustor 2 for combusting an air-fuel mixture to generate combustion gas, and a fuel supply amount to the combustor 2. It is equipped with a fuel control valve 19 that operates and an air compressor 3 that pumps air to the combustor 2. In addition, the gas turbine device includes a turbine control unit 11 that controls the turbine 1.

The turbine 1 has a plurality of rotary blades (not shown) for receiving a fluid and rotating, and is rotatably supported in a casing (not shown) via a rotary shaft 6. The air compressor 3 is configured to be driven by the turbine 1 via the rotating shaft 6 to compress air. The air compressor 3 is connected to the combustor 2 via a pipe 7, and the air compressed by the air compressor 3 is supplied to the combustor 2 via the pipe 7.

The fuel control valve 19 is arranged on the upstream side of the combustor 2, and the fuel supplied from a fuel supply source (not shown) is supplied to the combustor 2 after passing through the fuel control valve 19. The fuel control valve 19 has a variable opening, and the amount of fuel supplied to the combustor 2 is adjusted by operating the opening.

The fuel and compressed air supplied to the combustor 2 form an air-fuel mixture in the combustor 2, and the air-fuel mixture burns in the combustor 2 to generate high-temperature and high-pressure combustion gas. Then, by supplying this combustion gas to the turbine 1, the turbine 1 rotates at high speed. The generator 5 is connected to the end of the rotating shaft 6, and the turbine 1 is rotationally driven by the turbine 1 via the rotating shaft 6 to generate electric power.

The turbine control unit 11 performs feedback control with the turbine 1 as a control target. That is, a control for obtaining the current rotation speed and acceleration of the turbine 1 based on the detection value detected by the rotation speed detection unit 12 and setting this as a feedback value, and minimizing the deviation between this feedback value and the target value. Calculate the signal. Then, the flow rate of the fuel supplied to the combustor 2 is adjusted by operating the opening degree of the fuel control valve 19 according to the calculated control signal. In this way, by adjusting the amount of fuel supplied to the combustor 2, the amount of combustion gas supplied to the turbine 1 is adjusted, whereby the rotation speed and acceleration of the turbine 1 are controlled.

FIG. 2 is a schematic diagram showing an input / output path of a flameout determination unit included in the gas turbine system of this embodiment. As shown in FIG. 2, the gas turbine device according to the present embodiment includes an air-fuel ratio calculation unit 31 that calculates an air-fuel ratio of air and fuel in an air-fuel mixture, an exhaust temperature measurement unit 17 that measures an exhaust temperature, A temperature rise rate calculation unit 18 that calculates the temperature rise rate of the exhaust temperature based on the temperature measured by the exhaust temperature measurement unit 17, and an acceleration of the turbine 1 based on the detection value detected by the rotation speed detection unit 12. The acceleration calculation unit 15 and the frame-out determination unit 33 that determines the occurrence of a frame-out are provided.

In the air-fuel ratio calculation unit 31, the rotation speed detection unit 12
The air-fuel ratio is calculated based on the detected rotation speed of the turbine 1 and the opening degree of the fuel control valve 19. That is, the air supplied to the combustor 2 is the air compressor 3 as described above.
The air compressor 3 is supplied after being compressed by, and the air compressor 3 is driven by the turbine 1. Therefore, the mass of air in the air-fuel mixture is proportional to the rotation speed of the turbine 1. The amount of fuel supplied to the combustor 2 is proportional to the opening of the fuel control valve 19. Based on this, the air-fuel ratio calculation unit 31 calculates the air-fuel ratio based on the rotation speed of the turbine 1 detected by the rotation speed detection unit 12 and the opening degree of the fuel control valve 19.

The exhaust temperature measuring unit 17 is installed on the downstream side of the combustor 2, that is, on the exhaust side pipe of the turbine 1 (see FIG. 1).
The temperature of exhaust gas (mainly combustion gas) is measured. The temperature rise rate calculation unit 18 samples the temperature measured by the exhaust temperature measurement unit 17 at predetermined intervals, and compares the sampled value at that time with the previous sampled value to calculate the temperature rise rate of the exhaust gas. Is configured to calculate

The flame-out determination unit 33 is constantly sent the calculated values calculated by the air-fuel ratio calculation unit 31, the temperature increase rate calculation unit 18, and the acceleration calculation unit 15. Then, based on these calculated values, the frame-out determination unit 33 determines whether or not a frame-out has occurred. That is, the air-fuel ratio calculated by the air-fuel ratio calculation unit 31 is lower than a predetermined reference air-fuel ratio, the temperature increase rate of the exhaust temperature calculated by the temperature increase rate calculation unit 18 is negative, and the acceleration calculation unit 15
When the acceleration of the turbine 1 calculated by the above is negative, it is determined that the flameout has occurred. When the flameout determination unit 33 determines that the flameout has occurred, the emergency stop valve 32 is operated to stop the fuel supply to the combustor 2 as shown in FIGS. 1 and 2. .

The reason why the three factors of the air-fuel ratio, the exhaust gas temperature, and the acceleration of the turbine 1 are used as the factors for determining the occurrence of the flameout will be described with reference to FIG. FIG. 3 is a diagram showing, over time, how each numerical value of the gas turbine device shown in FIG. 1 fluctuates when a flameout occurs.

As shown in FIG. 3, when the flameout occurs, the combustion flame disappears and the combustion gas is not supplied to the turbine 1, so that the rotational speed (NR) of the turbine 1 decreases. Then, by the feedback control that tries to increase the decreasing rotational speed, the fuel control valve (Fuel Co
The opening of the ntrol valve, FCV) increases, and as a result, the air-fuel ratio (A / F) tends to decrease. Moreover, since the combustion flame is extinguished, the temperature of the combustion gas (EGT) is lowered. Further, since the rotational speed (NR) of the turbine 1 is reduced, the acceleration (ACCEL) of the turbine 1 is inevitably turned negative.

As described above, when the flameout occurs, the air-fuel ratio is lowered, the exhaust temperature is lowered, and the acceleration of the turbine 1 is converted to a negative value. Therefore, the air-fuel ratio, the exhaust gas temperature, and the acceleration of the turbine 1 are constantly monitored, the air-fuel ratio falls below a preset reference air-fuel ratio, the rate of increase in the exhaust gas temperature turns negative, and the turbine 1 If it is judged that the frame out has occurred only when the acceleration of turns to negative,
It is possible to accurately determine the occurrence of frame-out.

By adopting such a flameout determination method, the exhaust temperature does not decrease when the load on the gas turbine device increases, so it is not determined that flameout has occurred. Further, as compared to the conventional case where only the air-fuel ratio is used as the determination element for the occurrence of flameout, the reference air-fuel ratio can be raised and set as shown in FIG. As a result, when the flameout actually occurs, the decreasing air-fuel ratio quickly reaches the reference air-fuel ratio, so that it is possible to quickly determine the occurrence of the flameout. Therefore, it is possible to quickly stop the fuel supply after the flameout actually occurs and prevent an accident.

The gas turbine device of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0030]

As described above, according to the present invention,
It is judged that the frame-out has occurred only when all of the above three judgment criteria are satisfied. Therefore, when the load on the gas turbine device increases and the air-fuel ratio decreases, it is possible to prevent erroneous recognition that a flameout has occurred. Also, since there is no risk of misidentification due to such an increase in load, it is possible to raise the reference air-fuel ratio, which is the criterion for determining the occurrence of flameout, and as a result, if a flameout actually occurs, this can be quickly Can be detected.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a gas turbine device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an input / output path of a flameout determination unit included in the gas turbine device according to the embodiment of the present invention.

FIG. 3 is a diagram showing, over time, how each numerical value of the gas turbine device shown in FIG. 1 fluctuates when a flameout occurs.

FIG. 4 is a graph showing changes over time in numerical values when the load on a conventional gas turbine device increases.

[Explanation of symbols]

1 turbine 2 Combustor 3 air compressor 5 generator 6 rotation axes 7,8 piping 11 Turbine controller 12 Rotation speed detector 15 Acceleration calculator 17 Exhaust gas temperature measuring device 18 Temperature rise rate calculator 19 Fuel control valve 31 Air-fuel ratio calculator 32 Emergency stop valve 33 Frame-out judgment section A / F air-fuel ratio EGT exhaust gas temperature NR rotation speed FCV fuel control valve ACCEL acceleration LOAD Generator load

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masahiro Miyamoto             11-1 Haneda Asahi-cho, Ota-ku, Tokyo Co., Ltd.             Inside the EBARA CORPORATION (72) Inventor Masafumi Kataoka             11-1 Haneda Asahi-cho, Ota-ku, Tokyo Co., Ltd.             Inside the EBARA CORPORATION (72) Inventor Yasushi Furuya             11-1 Haneda Asahi-cho, Ota-ku, Tokyo Co., Ltd.             Inside the EBARA CORPORATION F-term (reference) 3G071 AB01 BA22 CA09 FA02 FA06                       GA06 HA01 HA05 JA04

Claims (4)

[Claims] 1. A flameout determination method for determining whether a flameout has occurred during operation of a gas turbine apparatus, wherein an air-fuel ratio of air and fuel in the air-fuel mixture is below a predetermined reference air-fuel ratio, and A flame that is characterized by determining that a flameout has occurred if the temperature rise rate of the exhaust temperature measured downstream of the combustor that burns the air-fuel mixture is negative and the turbine acceleration is negative. How to judge out. 2. The air-fuel ratio depends on the rotational speed of the turbine, which is substantially proportional to the amount of air supplied to the combustor, and the opening of a fuel control valve for adjusting the amount of fuel supplied to the combustor. The flameout determination method according to claim 1, wherein the air-fuel ratio is calculated based on the air-fuel ratio. 3. A gas turbine device for rotatively driving the turbine by combusting a mixture of air and fuel in a combustor and supplying combustion gas generated by the combustion to the turbine. An air-fuel ratio calculation unit that calculates the air-fuel ratio of air and fuel, a temperature increase rate calculation unit that calculates the temperature increase rate of the exhaust temperature measured on the downstream side of the combustor, and an acceleration that calculates the acceleration of the turbine. A calculation unit, the air-fuel ratio calculated by the air-fuel ratio calculation unit is below a predetermined reference air-fuel ratio, and the temperature increase rate of the exhaust temperature calculated by the temperature increase rate calculation unit is negative, and, A gas out determining unit that determines that a flame out occurs when the acceleration of the turbine calculated by the acceleration calculating unit is negative. Bottle apparatus. 4. An air compressor driven by the turbine to send air to the combustor under pressure, and a fuel control valve for controlling the amount of fuel supplied to the combustor are provided, and the air-fuel ratio calculation unit includes: The gas turbine device according to claim 3, wherein the air-fuel ratio is calculated based on the rotational speed of the turbine and the opening degree of the fuel control valve.