JP3772029B2 - Gas turbine combustor fuel supply system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel supply device for a gas turbine combustor that enables a stable supply of fuel to the gas turbine combustor.
[0002]
[Prior art]
In recent gas turbine plants, in order to further improve the plant thermal efficiency, the temperature of the combustion gas in the gas turbine combustor has been increased, and while the temperature of the combustion gas is increased, the NOx is further reduced. There is a growing demand for
[0003]
In addition, fuel is diversified along with the reduction of NOx, and plants that operate with high calorie gas fuel such as natural gas alone, or either high calorie gas fuel or liquid fuel depending on the fuel supply status. Alternatively, plants that are used in combination, and plants that use coal gasification gas, which is a low-calorie or medium-calorie gas fuel, and liquid fuel in combination are being put to practical use or being searched for.
[0004]
By the way, in a gas turbine plant using a high calorie gas fuel, the temperature of the gas turbine inlet is increased and the NOx is reduced. Combustion is one of the causes of NOx generation to achieve low NOx. It is necessary to reduce the generation of so-called thermal NOx, which suppresses the local high temperature portion of the gas. As a technique for suppressing the generation of thermal NOx, a lean premixed combustion method is known in which fuel and air are mixed and burned in advance in a lean combustion state.
[0005]
Stable by forming a diffusion combustion zone as a flame holding (fire type) on the head side of the gas turbine combustor and forming a lean premix combustion zone on the downstream (downstream) side as one method of the lean premix combustion method There is a method of suppressing the generation amount of thermal NOx while realizing combustion. In this method, there are two or more fuel systems such as a diffusion fuel system and a premixed fuel system, and there is, for example, one shown in FIG.
[0006]
The fuel system includes a pilot fuel supply system 4, a diffusion fuel supply system 5, a premixed fuel supply system 6, and the like bypassed from one mother pipe 3 having a fuel stop valve 1 and a fuel flow rate adjusting valve 2 interposed therebetween. It has become.
[0007]
The pilot fuel supply system 4 is used as diffusion combustion for flame holding, and is provided on a nozzle 11a provided on the head side of a combustion chamber 10a formed by a combustor liner 10 via a fuel flow rate adjusting valve 7a and a manifold 8a. Connected.
[0008]
The diffusion fuel supply system 5 is used for diffusion combustion from the start of the starting operation, and is connected to the nozzle 11b via the fuel flow rate adjusting valve 7b and the manifold 8b as described above.
[0009]
The premixed fuel supply system 6 is used for reducing the NOx concentration from the intermediate load operation of the gas turbine combustor 9, and is connected to the nozzle 11c via a fuel flow rate adjusting valve 7c and a manifold 8c. Note that the premix fuel system 6 is provided with a premix duct 12 facing the outlet side of the nozzle 11c, where the air supplied from the outside of the combustion chamber 10a is added to dilute the fuel.
[0010]
In the fuel system having such a configuration, the gas turbine combustor 9 supplies fuel to the pilot fuel supply system 4, the diffusion fuel supply system 5, and the premixed fuel supply system via the fuel stop valve 1 and the fuel flow rate adjustment valve 2. 6 is divided into a pilot combustion fuel A, a diffusion combustion fuel B, and a premixed combustion fuel C, and each of the divided fuels A, B, C is supplied to a fuel flow rate adjusting valve 7a. , 7b, 7c, manifolds 8a, 8b, 8c and nozzles 11a, 11b, 11c are supplied to the combustion chamber 10a to generate combustion gas.
[0011]
FIG. 5 shows that the pilot combustion fuel A, diffusion combustion fuel B, and premixed combustion fuel C from each of the fuel supply systems 4, 5, 6 are supplied to the combustion chamber 10a and supplied to the combustion chamber 10a. It is a fuel injection pattern diagram which makes G the total fuel flow volume to do.
[0012]
When the gas turbine combustor 9 performs the diffusion combustion operation and the premixed combustion operation, the pilot combustion fuel A in the pilot fuel supply system 4 and the diffusion combustion fuel in the diffusion fuel supply system 5 from ignition to about ½ load. B is supplied to the combustion chamber 10a and the diffusion combustion operation is performed, and the supply of the pilot combustion fuel A to the combustion chamber 10a is cut from about 1/2 load, and instead of the premixed fuel supply system 6 The premixed combustion fuel C is supplied to the combustion chamber 10a, and the premixed combustion operation is performed. Note that after the supply of the pilot combustion fuel A to the combustion chamber 10a is cut, the diffusion combustion fuel B functions as a flame holding.
[0013]
In this way, the diffusion combustion operation and the premixed combustion operation are separated from each other because the combustion gas temperature is low at low load, and when the premixed combustion fuel C is introduced into the combustion chamber 10a from the low load, CO or the like Based on the large amount of unburned matter. Therefore, the premixed fuel supply system 6 cuts the premixed combustion fuel C into the combustion chamber 10a from ignition to about ½ load.
[0014]
In addition, the gas turbine combustor 9 that performs the diffusion combustion operation and the premixed combustion operation increases the input amount of the premixed combustion fuel C into the combustion chamber 10a at the rated load for the purpose of promoting the reduction of NOx, and performs diffusion combustion. The amount of fuel B injected into the combustion chamber 10a is made as small as possible. In this case, the differential pressure before and after the nozzle 11b from which the diffusion combustion fuel B is ejected prevents combustion vibration and the like, and a differential pressure of a certain level or more is necessary for the necessity of stable combustion. Therefore, in order to make the differential pressure of the nozzle 11b more than a certain level while reducing the amount of diffusion combustion fuel B input to the combustion chamber 10a, the ejection opening area of the nozzle 11b has to be made less than a certain value. When the combustion operation is performed in this state, the pressure difference of the nozzle 11b becomes extremely large at the point where the flow rate of the diffusion combustion fuel B immediately before the premixed combustion fuel C is introduced into the combustion chamber 10a, and the gas Problems such as plant thermal efficiency, increased costs, and equipment safety, such as increased compressor power and increased system equipment pressure. Therefore, as shown in FIG. 5, the fuel for diffusion combustion is selectively used as pilot combustion fuel A and diffusion combustion fuel B, and the pilot combustion fuel A and diffusion combustion from ignition to about ½ load. When the fuel B is used at the same time and reaches about ½ load, the supply of the pilot combustion fuel A to the combustion chamber 10a is stopped, and the diffusion combustion fuel B is supplied to the combustion chamber 10a instead. The fuel pressure for the premixed combustion C is started to be supplied to the combustion chamber 10a, and the fuel pressure is extremely increased and the differential pressure of the nozzle 11b during rated load operation is optimized. When the load is J, the pilot combustion fuel A is supplied to the combustion chamber 10a at zero.
[0015]
Even in a gas turbine plant that uses both liquid fuel and high-calorie gas fuel, when using liquid fuel alone at the beginning of startup operation, do not flow coal gasification gas fuel into the coal gasification gas fuel supply system. It has become.
[0016]
Furthermore, even in a gas turbine plant that uses both liquid fuel and coal gasification gas fuel, when using liquid fuel alone at the beginning of startup operation, no coal gasification gas fuel is allowed to flow through the coal gasification gas fuel supply system. It is like that.
[0017]
Thus, in a gas turbine plant that uses a plurality of types of fuel or a single type of fuel for different purposes, at least one or more of the plurality of fuel supply systems during start-up operation or intermediate load operation. The use was discontinued and we were dealing with low NOx emissions that were within legal limits.
[0018]
[Problems to be solved by the invention]
Since the gas turbine combustor 9 shown in FIG. 4 skillfully uses a plurality of fuel supply systems depending on the purpose, whether it is a single type or a plurality of types of fuel, it is sufficient for low NOx reduction. Although it can be addressed, there are still some problems, one of which is draining the fuel.
[0019]
The gas turbine combustor 9 includes a plurality of fuel supply systems, and is not used when at least one of the plurality of fuel supply systems is not used during start-up operation or intermediate load operation. The combustion gas or air from the combustion chamber 10a may flow back into the fuel supply system due to back pressure. In this case, if the combustion gas or the like flows back to the unused fuel supply system, the combustion gas or the like may be condensed in the pipe due to the temperature difference, and the fuel may be drained. When new fuel is supplied to the drained fuel, the gas turbine combustor 9 may misfire due to the drained fuel even when the fuel is ignited during ignition in the start-up operation.
[0020]
In addition, if the drained fuel is retained in the fuel supply system, as a result of long-term use, excessive stress may be generated in the fuel supply system, causing an accident, and stable fuel supply may not be possible. .
[0021]
The present invention has been made on the basis of such circumstances, and even if there is a fuel supply system that is not used among a plurality of fuel supply systems during operation, a new fuel is added to the fuel supply system. An object of the present invention is to provide a fuel supply device for a gas turbine combustor that can stably supply fuel when supplying fuel.
[0022]
[Means for Solving the Problems]
In order to achieve the above object, a fuel supply device for a gas turbine combustor according to the present invention is provided with a plurality of combustion supply systems in a gas turbine combustor, so that a single genus fuel and different types are provided. In the fuel supply apparatus for a gas turbine combustor that supplies at least one of the fuels to the plurality of fuel supply systems in accordance with an operating situation, the plurality of fuel supplies using at least one of the single type fuel and the different type fuel. Among the systems, a fuel supply system that is not used during operation of the gas turbine combustor is provided with means for treating fuel drain.
[0023]
In order to achieve the above object, the fuel supply apparatus for a gas turbine combustor according to the present invention uses the fuel drain processing means during operation of the gas turbine combustor. This is a combination of a non-fuel supply system, a drain pot connected to a manifold provided in the fuel supply system, and a control valve that causes the fuel drain staying in the drain pot to flow out of the system.
[0024]
Further, in order to achieve the above object, the fuel supply device for a gas turbine combustor according to the present invention has a control valve in which the drain of the drain pot exceeds a preset level. It is equipped with a transmitter that is sometimes opened.
[0025]
In order to achieve the above object, the fuel supply apparatus for a gas turbine combustor according to the present invention uses a means for treating fuel drain as described in claim 4 during the operation of the gas turbine combustor. A fuel supply system that is not installed, an ultrasonic detection device that is mounted on a manifold provided in the fuel supply system, and a control valve that causes the fuel drain that stays in the manifold to flow out of the system. It is.
[0026]
Further, in order to achieve the above object, the fuel supply device for a gas turbine combustor according to the present invention, as described in claim 5, the ultrasonic detection device determines the presence of an ultrasonic sensor and fuel drain. It is configured by combining with a determiner.
[0027]
In order to achieve the above object, the fuel supply apparatus for a gas turbine combustor according to the present invention is characterized in that the different types of fuel are liquid fuel, high calorie gas fuel, coal gasification gas fuel, as described in claim 6. These are at least two kinds of fuels.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a fuel supply device for a gas turbine combustor according to the present invention will be described with reference to the drawings and reference numerals attached in the drawings.
[0029]
FIG. 1 is a schematic system diagram showing a first embodiment of a fuel supply device for a gas turbine combustor according to the present invention applied to, for example, a combined cycle power plant.
[0030]
A combined cycle power plant incorporating a fuel supply device for a gas turbine combustor according to the present embodiment includes a gas turbine plant 13, a steam turbine plant 14, and an exhaust heat recovery boiler 15, and the gas turbine plant 13 and the steam turbine plant 14. Are connected by a single turbine shaft 16.
[0031]
The gas turbine plant 13 includes an air compressor 17, a gas turbine combustor 18, and a gas turbine 19. The air AR sucked by the air compressor 17 is compressed to a high pressure, and the high-pressure air is gas turbined together with the gas fuel GFUL. The combustion gas is supplied to the combustor 18 where combustion gas is generated, and the generated combustion gas is guided to the gas turbine 19 as a gas turbine driving gas to perform expansion work.
[0032]
Further, the exhaust heat recovery boiler 15 generates steam using the exhaust gas that has finished the expansion work in the gas turbine 19 as a heat source, and then releases it to the atmosphere via the chimney 20.
[0033]
The steam turbine plant 14 includes a steam turbine 21, a generator 22, and a condenser 23. The steam supplied from the exhaust heat recovery boiler 15 to the steam turbine 21 performs expansion work, and rotational torque generated at that time. Then, the generator 22 is driven, and the steam that has finished the expansion work is supplied to the condenser 23 and condensed, and the condensed water (condensate) is fed back to the exhaust heat recovery boiler 15 as feed water.
[0034]
On the other hand, the gas turbine combustor 18 is provided with a fuel supply system 24.
[0035]
The fuel supply system 24 includes a fuel compressor 25 that boosts the gas fuel GFUL, a main fuel supply system 27 that supplies the boosted gas fuel GFUL to the main nozzle 26 of the gas turbine combustor 18, and a bypass from the main fuel supply system 27. The first sub fuel supply system 29a for supplying the high pressure gas fuel GFUL to the first sub nozzle 28a of the gas turbine combustor 18, and the second sub nozzle 28b of the gas turbine combustor 18 by bypassing from the first sub fuel supply system 29a. And a second sub fuel supply system 29b for supplying high-pressure gas fuel GFUL.
[0036]
The fuel supply system 24 includes a fuel drain processing system 30 that is bypassed from the first sub fuel supply system 29a.
[0037]
As shown in FIG. 2, the fuel drain processing system 30 accumulates on the fuel flow rate adjustment valve 31a side and the first manifold 32a of the first sub fuel supply system 29a connected to the first sub nozzle 28a of the gas turbine combustor 18. A drain pot 33 that once collects the gas fuel drain is provided, and the gas fuel drain collected in the drain pot 33 is controlled to open / close the drain discharge valve 35 and the drain shut-off valve 36 by a signal from the level transmitter 34 so as to flow out of the system. It has become. In this case, when the gas fuel drain in the drain pot 33 exceeds a preset drain value, the level transmitter 34 opens the drain discharge valve 35 and the drain cutoff valve 36, and the gas fuel drain becomes lower than the set value. The drain discharge valve 35 and the drain shut-off valve 36 are closed.
[0038]
Further, the drain pot 33 is provided with a balance pipe 37 that balances the pressure with the first manifold 32a to improve the flow of the gas fuel drain. 2 shows that the gas fuel GFUL is supplied from the second sub fuel supply system 29b to the second sub nozzle 28b of the gas turbine combustor 18 through the fuel flow rate adjusting valve 31b and the second manifold 32b during the start-up operation or the intermediate load operation. However, this is merely an example, and when the gas fuel GFUL is not supplied to the second sub fuel supply system 29b during start-up operation or intermediate load operation, the above-mentioned fuel is supplied to the second sub fuel supply system 29b. A drain treatment system 30 may be provided.
[0039]
2 omits the main fuel supply system 27 and uses a single type of gas fuel GFUL as the fuel. For example, during start-up operation, liquid fuel is supplied to the second sub-fuel supply system 29b. The high-calorie gas fuel may be supplied to the first sub-fuel supply system 29b during the intermediate load operation, or the liquid fuel may be used separately during the start-up operation and the intermediate load operation. Good.
[0040]
By the way, the gas turbine combustor 18 is installed between the air compressor 17 and the gas turbine 19, the number of cans is 6 to 32, and the number of cans is as shown in FIG. The igniter (not shown) is provided in one or two of the 6 to 32 cans, and the combustion gas generated by the igniter is connected to the next can without the igniter via the communication pipe 38. Propagate sequentially. For this reason, the gas turbine combustor 18 is a nozzle that is not used due to a pressure difference due to a bad flow of combustion gas and a difference in the flow of combustion gas if there is a manufacturing error or an assembly error in each component. As a result, the combustion gas may flow back to the manifold and drain as described above.
[0041]
The fuel supply apparatus of the gas turbine combustor according to the present embodiment focuses on fuel draining. The fuel drain processing system 30 is provided in the first sub fuel supply system 29a described above, and the fuel drain processing system 30 is the first. The fuel drain accumulated in the sub fuel supply system 29a is processed.
[0042]
Therefore, according to the present embodiment, since the fuel drain processing system 30 is provided in the first sub fuel supply system 29a and the fuel drain is reliably processed, the misfire of the combustion gas is prevented when the gas fuel GFUL is ignited. The gas fuel GFUL can be supplied to the gas turbine combustor 18 in a stable state.
[0043]
FIG. 3 is a schematic system diagram showing a second embodiment of a fuel supply device for a gas turbine combustor according to the present invention. In addition, the same code | symbol is attached | subjected to the part which is the same as that of the structure part of 1st Embodiment, or respond | corresponds.
[0044]
The fuel supply device of the gas turbine combustor according to the present embodiment supplies, for example, liquid fuel LFUL as fuel to the second sub fuel supply system 29b during start-up operation and uses coal gasification as fuel during intermediate load operation. The gas fuel CFUL is supplied to the first sub fuel supply system 29a for use.
[0045]
In general, the coal gasification gas fuel CFUL is 1/5 to 1/10 of the calorie of the high calorie gas fuel, and accordingly, the input amount to the gas turbine combustor 18 is also larger than that of the high calorie gas fuel. 5 to 10 times. For this reason, the opening area of the nozzle is also larger than when high-calorie gas fuel is used.
[0046]
For example, during start-up operation, when the liquid fuel LFUL is supplied to the second sub fuel supply system 29b and used, and the supply of the coal gasification gas fuel CFUL to the first sub fuel supply system 29a is stopped, the gas turbine When the combustor 18 generates combustion gas from the liquid fuel LFUL supplied from the second manifold 32b via the second sub nozzle 28b, the opening area of the first sub nozzle 28a is large. The back flow to the 1 sub fuel supply system 29a and the first manifold 32a is further increased, and the fuel drain generated is increased accordingly. When switching from the second sub nozzle 28b to the first sub nozzle 28a, the combustion gas misfires. The potential is great.
[0047]
This embodiment pays attention to such points, and an ultrasonic sensor 39 is provided in the first sub-fuel supply system 29a and the first manifold 32a, and the first sub-fuel supply system 29a and the first manifold 32a stay. The determination device 40 determines the presence or absence of fuel drain, and when the fuel drain stays in the first sub fuel supply system 29a and the first manifold 32a, the drain discharge valve 35 and the drain shutoff valve 36 are opened. is there.
[0048]
Therefore, according to the present embodiment, the presence or absence of the fuel drain staying in the first sub fuel supply system 29a and the first manifold 32a is detected by the ultrasonic sensor, and when the fuel drain stays, the drain discharge valve 35, Since the gas was discharged out of the system from the drain shut-off valve 36, it was possible to prevent misfiring of the combustion gas when the coal gasification residue fuel CFUL was ignited, and to stabilize the coal gasification gas fuel CFUL. 18 can be supplied.
[0049]
【The invention's effect】
As described above, the fuel supply device for a gas turbine combustor according to the present invention is provided with a plurality of fuel supply systems in the gas turbine combustor, and starts or operates a single type or different types of fuel in the plurality of fuel supply systems. While the gas turbine combustor is operated and supplied according to the operation status of the intermediate load operation, the fuel drain that stays in the unused fuel supply system is provided outside the system. Misfires can be reliably prevented, and single or different types of fuel can be stabilized and supplied to the gas turbine combustor.
[Brief description of the drawings]
FIG. 1 is a schematic system diagram in which a fuel supply device for a gas turbine combustor according to the present invention is applied to a combined cycle power plant.
FIG. 2 is a schematic system diagram showing a first embodiment of a fuel supply device for a gas turbine combustor according to the present invention.
FIG. 3 is a schematic system diagram showing a second embodiment of a fuel supply apparatus for a gas turbine combustor according to the present invention.
FIG. 4 is a schematic system diagram showing a conventional fuel supply device for a gas turbine combustor.
FIG. 5 is a conventional fuel input pattern diagram for supplying fuel to a combustion chamber in accordance with the operating state of a gas turbine combustor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fuel stop valve 2 Fuel flow control valve 3 Mother pipe 4 Pilot fuel supply system 5 Diffusion fuel supply system 6 Premixed fuel supply system 7a, 7b, 7c Fuel flow control valve 8a, 8b, 8c Manifold 9 Gas turbine combustor 10 Combustion Liner 10a Combustion chamber 11a, 11b, 11c Nozzle 12 Premixing duct 13 Gas turbine plant 14 Steam turbine plant 15 Waste heat recovery boiler 16 Turbine shaft 17 Air compressor 18 Gas turbine combustor 19 Gas turbine 20 Chimney 21 Steam turbine 22 Power generation Machine 23 Condenser 24 Fuel supply system 25 Fuel compressor 26 Main nozzle 27 Main fuel supply system 28a First sub nozzle 28b Second sub nozzle 29a First sub fuel supply system 29b Second sub fuel supply system 30 Fuel drain processing systems 31a, 31b Fuel flow adjustment valve 32a First manifold 32b Second manifold 33 Drain pot 34 Level transmitter 35 Drain discharge valve 36 Drain shut-off valve 37 Balance pipe 38 Communication pipe 39 Ultrasonic sensor 40 Judgment device

Claims (6)

In the fuel supply apparatus for a gas turbine combustor, the gas turbine combustor is provided with a plurality of combustion supply systems, and supplies at least one of a single kind fuel and a different kind of fuel to the plurality of fuel supply systems in accordance with operating conditions. Of the plurality of fuel supply systems using at least one of the single type fuel and the different type fuel, means for treating fuel drain is provided in a fuel supply system that is not used during operation of the gas turbine combustor. A fuel supply device for a gas turbine combustor. The fuel drain processing means includes a fuel supply system that is not used during operation of the gas turbine combustor, a drain pot connected to a manifold provided in the fuel supply system, and a fuel drain retained in the drain pot. 2. The fuel supply device for a gas turbine combustor according to claim 1, wherein the control valve is configured to be combined with a control valve for causing the gas turbine combustor to flow out. 3. The fuel supply apparatus for a gas turbine combustor according to claim 2, wherein the control valve includes a transmitter that opens when the fuel drain of the drain pot exceeds a preset level. The means for treating the fuel drain includes a fuel supply system that is not used during operation of the gas turbine combustor, an ultrasonic detector attached to a manifold provided in the fuel supply system, and a residence in the fuel supply system and the manifold. 2. A fuel supply device for a gas turbine combustor according to claim 1, wherein the fuel drain is configured to be combined with a control valve for causing the fuel drain to flow out of the system. 5. The fuel supply device for a gas turbine combustor according to claim 4, wherein the ultrasonic detection device is configured by combining an ultrasonic sensor and a determination device for determining the presence or absence of fuel drain. 2. The fuel supply device for a gas turbine combustor according to claim 1, wherein the different kinds of fuels are at least two kinds of fuels, liquid fuel, high calorie gas fuel, and coal gasification gas fuel.

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