JP2001090950A - Gas turbine combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas turbine combustor, reducing the variability of flow rate of fuel by regulating flowing condition in a manifold and capable of preventing increase in combustion vibration or the discharging amount of NOx. SOLUTION: In a fuel supplying system for a gas turbine combustor, consisting of a plurality of sets of combustors 3, a fuel pipeline 14, a manifold 13 and a branch pipe 12, the fuel pipeline 14 is provided with a flow rate distributing valve 18 at the connecting part between the fuel pipeline 14 and a bypass pipeline 17 while the fuel pipeline 14 and the bypass pipeline 17 communicate with the manifold 13 through different routes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine combustor, and more particularly to a fuel supply system for supplying gas to the gas turbine combustor.

[0002]

2. Description of the Related Art Conventionally, a gas turbine combustor generally employed is composed of a plurality of combustors, in each of which a fuel and a compressed air are reacted to generate a high-temperature and high-pressure combustion gas. Is formed.

In order to supply fuel to each combustor, the fuel in the fuel tank is pressurized by a gas compressor or the like, and is introduced into each combustor via a manifold through a fuel pipe. The manifold is provided with the same number of branch pipes as the number of combustors, and fuel is supplied to each combustor through this branch pipe. A pressure control valve and a flow control valve are provided in the middle of the fuel pipe, and the fuel flow is controlled by controlling these valves.

[0004] On the other hand, in the method of supplying combustion air, compressed air discharged from a compressor is guided into a vehicle interior, passes through an air flow path formed by an inner cylinder and an outer cylinder of each combustor, and burns. It is introduced inside the vessel. The fuel and air supplied in this way are reacted inside the combustor to generate combustion gas, and the gas turbine is driven to generate power.

[0005]

Normally, a fuel manifold is provided with a plurality of branch pipes for supplying fuel to a combustor, and the fuel flowing from the fuel pipe is connected to the fuel pipe at the start of supply. After filling the inside of the manifold while supplying part of the fuel to the combustor from the nearby branch pipe,
It is configured to supply equal fuel to each combustor.

However, a distribution pipe such as a manifold has a structure in which the static pressure distribution in the manifold is completely reduced due to the effects of branch flow loss due to the branch pipe, pressure loss due to separation vortex at the branch and bend, and pipe friction loss. It is difficult to make them uniform, and there is a slight pressure difference between the combustor connected to each branch pipe and the pressure inside the manifold, and the fuel flow supplied to each combustor is also uniform. No.

[0007] The compressed air for combustion is guided from the compressor to the passenger compartment, and is introduced into the inside of the combustor through an air passage formed by an inner cylinder and an outer cylinder of each combustor. Due to the influence of the shape of the flow path introduced from the compressor into the cabin, a pressure loss distribution also occurs inside the cabin, and the pressure loss distribution also causes a distribution of air flow to each combustor. As described above, these air flow distributions are caused by the air intake structure of the compressor, the flow path shape determined by the turbine casing structure and the transition piece shape, the structure of the vehicle compartment, and the like. It can be extensive.

Further, deviations in the fuel flow rate and air flow rate between the combustors also occur due to variations in the components of each combustor. Due to these effects, the combination of the distribution of the fuel and air flow rates causes subtle combustion characteristics. When driving, if the accumulated effects continue for a long time,
This may affect the life of the combustor and turbine blades.

With the manifold structure as in the prior art shown in Japanese Patent Application Laid-Open No. 8-135910, an effect can be expected in that the pressure distribution inside the manifold is made uniform and the fuel supplied to the combustor is made uniform. However, in the prior art, it is not possible to expect to make the fuel and air flow ratio of each combustor uniform by the combustion air flow distribution, and it is also impossible to control the flow state inside the manifold, as shown below. Issues were considered.

That is, the flow state inside the manifold temporally and spatially fluctuates due to the turbulence due to the fuel flow itself and the fluctuation of the internal pressure of the combustor, and this fluctuation further produces a pressure distribution, thereby supplying the fuel to each combustor. It is conceivable that the fuel flow rate that forms a temporal and spatial pressure distribution, resulting in cans with increased combustion oscillations, combustion temperatures, NOx emissions, and the like.

In a gas turbine that is operated for a long period of time, such a deviation in combustion characteristics occurring in a fixed combustor impairs the reliability of the gas turbine.

[0012]

In order to achieve the above object, a first feature of a gas turbine combustor according to the present invention is as follows.
In a gas turbine combustor including a plurality of gas turbine combustors for supplying fuel and air and generating a high-temperature combustion gas, and a fuel supply to the plurality of combustors is performed from a fuel pipe via a manifold. , A bypass pipe is provided in the fuel pipe, the fuel pipe is connected to the manifold through a different route from the fuel pipe, and a flow distribution control mechanism is provided in the bypass pipe branch portion, and the flow distribution control mechanism measures a state quantity related to combustion. The control is based on the

[0013] A second feature of the present invention is that the manifold has a divided structure, and the divided manifold includes:
A bypass pipe branched from the fuel pipe is connected, and a flow distribution control mechanism is provided at each bypass pipe branch portion, and the flow distribution control mechanism performs control based on a measurement result of a state quantity related to combustion. .

[0014] With the gas turbine combustor thus configured, the generation of static pressure distribution inside the fuel manifold can be reduced and a uniform fuel flow can be supplied to each combustor, as in the prior art. Furthermore, when a deviation occurs in the air flow rate, the fuel flow rate can be controlled, so that the fuel-air ratio, which is the ratio of fuel to air, is kept constant, and abnormal combustion such as increased combustion vibration can be prevented. It becomes possible.

Further, even when the flow rate of fuel supplied to the manifold is in a steady state, the flow state inside the manifold can be adjusted by controlling the flow rate distribution control mechanism provided at the bypass pipe branch portion. The above problem can be solved by suppressing the occurrence of a temporally and spatially varying pressure distribution formed inside the manifold. Further, in the present invention, since the flow distribution control mechanism is controlled based on information such as combustion vibration, combustor metal temperature, and exhaust gas temperature, an operation monitoring device for a gas turbine can be added to the present invention. In the test run, the operating condition of the flow distribution control device is checked so that optimum flow distribution can be performed under all operating conditions from the start of the gas turbine to the rated load, and by incorporating it into the control device, Under the operating conditions, the flow distribution control device can be operated, the operation can always be performed with the optimal flow distribution, and a stable combustion state can be maintained.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a main part of a gas turbine plant including a combustor according to a first embodiment of the present invention. This gas turbine plant is mainly connected to a gas turbine 2 and a compressed air 1 for combustion.
The compressor 1 is configured by a compressor 1 and a combustor 3 that obtains zero. The compressed air 10 discharged from the compressor 1 is guided to the combustor 3 through a compressed air flow path and is formed inside the combustor 3. The fuel is burned together with the fuel in the inner cylinder 6. The combustion gas 11 generated by the combustion is injected into the gas turbine 2 via the transition piece 7 to drive the gas turbine 2.
And, although not shown, the power is generally generated by a generator connected to the gas turbine.

The main structure of the combustor 3 is that an inner cylinder 6 for producing combustion gas 11, a transition piece 7, a fuel nozzle 8 for supplying fuel, and an ignition plug 4 for igniting the combustor 3 include an outer cylinder. Closed with 5. A plurality of combustors 3 are circumferentially arranged, and the adjacent combustors are connected to the inner cylinder 6 by a flame propagation pipe 9.

Next, the fuel supply system to the combustor 3 will be briefly described. Although not shown, the fuel in the fuel tank is pressurized to a predetermined pressure by a gas compressor or the like, passes through a fuel mother pipe, and is branched into fuel pipes 14 each connected to a gas turbine. Thereafter, the mixture is guided to the manifold 13 and supplied to each combustor 3 by a branch pipe installed in the manifold 13. The flow rate of the fuel gas supplied to each combustor 3 is determined by a pressure control valve 16 and a flow control valve 15 provided in the fuel pipe 14.

In the first embodiment of the present invention, a fuel bypass pipe 17 is provided in a fuel pipe 14, and a connection between the fuel bypass pipe 17 and the manifold 13 is located at a position opposed to a connection between the fuel pipe 14 and the manifold 13. Installed in the fuel pipe 1
A connection portion between the fuel supply pipe 4 and the fuel bypass pipe 17 is provided with a flow distribution valve 18 that can adjust the flow distribution and a flow distribution valve control device 19 that issues an operation command for the flow distribution valve 18. Further, the combustor is provided with a combustion vibration sensor 20 for monitoring a combustion state, a thermocouple 21 for monitoring a combustor metal temperature, and a thermocouple 22 for monitoring a combustor exhaust gas temperature. Is configured to receive and control signals of combustion vibration, combustor metal temperature, and combustor exhaust gas temperature. Further, the flow distribution valve control device 19 is provided with an operation state monitoring device 23, and is configured to be able to control the flow distribution valve 18 according to the operation state of the gas turbine.

Next, the operation of the gas turbine and the operation of the flow distribution valve 18 of the first embodiment according to the present invention will be described. First, when the gas turbine is started, the flow control valve 15 is opened by the ignition command of the combustor 3, and the fuel is supplied to the manifold 13.
Flows into At this time, since the flow distribution valve 18 operates so as to supply all the fuel to the fuel pipe 14 side, the fuel flows into the manifold 13 through the fuel pipe 14. The fuel that has flowed into the manifold 13 flows down the manifold 13 while supplying fuel to each combustor, and reaches a position facing the joint of the fuel pipe 14. A spark plug 4 is installed at a position facing the joint of the fuel pipe 14, that is, at a position where the fuel reaches the slowest, ignites the spark plug installation can and causes the flame to be transferred to the adjacent can by the flame spread pipe 9, Ignite all combustors.

In the prior art, since fuel flows into the manifold from two systems, when the spark plug can ignites, the fuel concentration of the other combustor is lower than that of the spark plug can, which may cause an ignition failure. However, in the present embodiment, the flow distribution valve 18 is controlled so that the fuel flows only through the fuel pipe 14, so that the fuel concentration at which the combustor provided with the spark plug 4 ignites becomes different from the other fuels. Since the fuel is sufficiently supplied to all the combustors, the ignition performance can be improved.

When an ignition failure occurs, the fuel supply amount and the supply pressure are changed and adjusted in the conventional example.
In this embodiment, in addition to this, by controlling the flow distribution valve 18, it is possible to adjust the flow state of the fuel flowing into the manifold, and the adjustment range for the ignition characteristics is wider than in the prior art.

Next, a pressure gradient is generated inside the manifold 13 due to an increase in the amount of fuel supplied due to an increase in the load of the gas turbine and variations in the components of each combustor, causing a deviation in the flow rate of the fuel supplied to the combustor. Is likely to occur.

However, the present embodiment is effective in controlling the flow distribution valve 18 based on combustion vibration and metal temperature information to reduce variations in the fuel flow rate.
It is possible to prevent an increase in the amount of Ox emission beforehand.

Further, when the operating state of the gas turbine changes, turbulence due to combustion vibration and fuel flow occurs, and a temporal and spatial pressure distribution is generated inside the manifold 13, whereby the gas is supplied to the combustor. It is conceivable that a deviation occurs in the fuel flow to be performed, and as a result, the combustion oscillation and the NOx emission amount increase.

The pressure distribution generated inside the manifold 13 is such that when the fluctuation of the internal pressure of the combustor propagated from the branch pipe 12 and the fluctuation period of the vortex generated when flowing into the manifold 13 are synchronized, the pressure distribution is changed. And the occurrence of combustion instability.

However, according to this embodiment, the combustion oscillation, the combustor metal temperature, and the exhaust gas temperature are constantly monitored, and if the dispersion tends to increase, the flow distribution valve 18 is controlled based on these information. And manifold 1
3, it is possible to prevent the occurrence of pressure distribution inside the manifold 13 by changing the flow state within the manifold 3, reduce the combustion vibration level, the combustor metal temperature, and the exhaust gas temperature, and secure stable combustion. It becomes possible.

The gas turbine depends on the operating conditions.
Since the fuel and air flow rates are different from each other, the pressure distribution in the manifold 13 may change every moment. Therefore, under each operating condition,
It is conceivable that the balance of the fuel flow supplied to each combustor will be different, which may cause different problems. However, according to the present embodiment, the operation conditions are managed during the test operation, and the flow distribution valve 18 is controlled under each operation condition.
By confirming the optimal operation state of the above, and incorporating this information into the operation state monitoring device 23 and the flow distribution valve control device 19,
Under all operating conditions from the start to the rated load, the flow distribution valve 18 can be operated to perform an optimal flow distribution, and a stable combustion state can always be maintained.

Next, a second embodiment of the present invention will be described with reference to FIG. The basic components of this embodiment are the same as those of the first embodiment. In this embodiment, four partition plates 24 are provided on the manifold 13 and the manifold 13 is divided into four parts.
Into two systems, and branch pipes 25, 26, 27,
28, the manifold 13 divided into four parts is connected to each other, and the length of the branch pipe 26 is set to the other branch pipes 25, 27,
It is configured to be longer than 28. Further, the flow distribution valves 18 and 2 are provided at the branch between the fuel pipe 14 and the fuel bypass pipe 17 and at the branch between the fuel pipe 14 and the fuel bypass pipe 17, respectively.
9 and 30 are installed, and these flow distribution valves 18,
Reference numerals 29 and 30 are configured to receive and control information on combustion oscillation, combustor metal temperature, and combustor exhaust gas temperature.

Further, the flow distribution valve control device 19 is provided with an operation state monitoring device 23 so that the flow distribution valves 18, 29 and 30 can be controlled according to the operation state of the gas turbine. ing.

With this configuration, when the combustor is started, the branch pipes 26 of the bypass pipe 17 are configured to be longer than the branch pipes 25, 27, 28 by uniformly distributing the flow distribution valves 18, 29, 30. In this case, the fuel arrival is delayed, and in particular, the fuel arrival to the ignition plug 4 installed combustor can be made the slowest. Since the fuel is sufficiently supplied to the combustor, the ignition performance is not impaired.

Further, in the gas turbine, a pressure distribution is generated in the vehicle interior due to the shape of the air flow path from the compressor to the vehicle interior and the air flow fluctuation caused by the load increase, and the air flow supplied to the combustor is increased. It is conceivable that a deviation occurs in. When the supplied fuel flow rate is constant, if the air flow rate is small, the fuel-air ratio, which is the ratio of fuel to air, increases, and combustion vibration and NOx
Emissions may increase.

In the first embodiment, the flow state of the fuel flow rate flowing into the manifold 13 is controlled,
Although it is possible to prevent the occurrence of an internal pressure distribution and perform stable combustion, it was not possible to expect a significant effect on the combustion instability problem caused by the fluctuation of the air flow rate.

However, in the second embodiment, since the fuel flow supplied to each of the divided manifolds 13 can be controlled, even if the air flow distribution is uneven, the fuel flow can be controlled by controlling the fuel flow. In addition, the fuel-air ratio can be made constant, and combustion oscillation and an increase in NOx emission can be prevented.

[0035]

As described above, according to the present invention, the fuel flow state in the manifold can be adjusted, the combustion vibration and the NOx generation amount can be reduced, and the temperature of the combustor metal and the exhaust gas temperature can be prevented from rising. Has the effect of doing

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a first embodiment of the present invention and its configuration.

FIG. 2 is a diagram illustrating a second embodiment of the present invention and its configuration.

[Description of Signs] 1 ... Compressor, 2 ... Gas turbine, 3 ... Combustor, 4 ... Ignition plug, 6 ... Inner cylinder, 7 ... Transition piece, 8 ... Burner, 10 ... Compressed air, 13 ... Manifold, 14 ... Fuel pipe, 15: flow control valve, 16: pressure control valve, 17: fuel bypass pipe, 18: flow distribution valve, 19: flow distribution valve control device, 20: combustion vibration monitoring sensor, 21: combustor metal temperature monitoring Thermocouple for monitoring, 22: thermocouple for monitoring exhaust gas temperature, 23: monitoring device for operating condition, 24: partition plate.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaya Otsuka 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Power & Electric Development Laboratory, Hitachi, Ltd. (72) Inventor Tomoya Murota Omika-cho, Hitachi City, Ibaraki Prefecture 7-2-1, Hitachi, Ltd. Power and Electricity Development Laboratory (72) Inventor Narika Kobayashi 7-2-1, Omika-cho, Hitachi, Ibaraki Pref. Hitachi, Ltd. Power and Electricity Development Laboratory

Claims (3)

[Claims] 1. A fuel cell system comprising: a plurality of gas turbine combustors for supplying fuel and air to generate a high-temperature combustion gas, wherein fuel is supplied to the plurality of combustors from a fuel pipe via a manifold. In a gas turbine combustor, a gas pipe combustor is provided, wherein a bypass pipe is provided in the fuel pipe, a manifold is connected to the fuel pipe by a different path from the fuel pipe, and a flow distribution control mechanism is provided in a branch of the bypass pipe. 2. The gas turbine combustor according to claim 1, wherein said flow distribution control mechanism is controlled by a state quantity of combustion state monitoring. 3. The gas turbine combustor according to claim 1, wherein the manifold has a divided structure, and a bypass pipe branched from a fuel pipe is connected to each of the divided manifolds. A gas turbine combustor characterized in that a flow distribution control mechanism is provided at a branch portion, and the flow distribution control mechanism is controlled by a state quantity of combustion state monitoring.