JP2000054857A - Gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the heat efficiency over a wide load band by combining a pilot burner for performing a diffusive combustion by use of only air free from moisture with a burner operated by the air having a large quantity of moisture added thereto to constitute a combustor. SOLUTION: The air 1 sucked out of a system is compressed by a compressor 4 and discharged as compressor-discharged air 5, and the air 8 of the discharged air necessary to operate a pilot burner is branched in a prescribed flow rate by a branch air flow regulating valve 6, and supplied to a combustor 10 without humidifying. The compressor-discharged air after branched is cooled by an outlet cooler 11 and supplied as low-temperature high-pressure air 12 to a humidification tower 19. The high-pressure air 12 is mixed with sprayed supplying water 13 in the humidification tower 19, the highly humid air 22 is introduced into a regenerating heat exchanger 23, and the highly humid air 22 leaving the regenerative heat exchanger 23 is supplied as combustor cooling air 28 to the combustor 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine, and more particularly to a combustor for a high-humidity gas turbine aiming at increasing output and improving thermal efficiency by adding moisture to air.

[0002]

2. Description of the Related Art An example of a high-humidity gas turbine apparatus for imparting moisture to air is disclosed in Japanese Patent Publication No. 1-19053 and Japanese Patent Publication No. 1-1310.
Although these are disclosed in Japanese Patent Publication No. 12, all of them relate to static characteristics at the time of rated operation, and do not consider problems at the time of transient characteristics such as starting and load change.

[0003]

In the gas turbine apparatus seen in the above-mentioned example, since air involved in combustion is supplied collectively, if the combustion speed is reduced by adding moisture to the air, The combustion stability is significantly reduced throughout the combustor, making it difficult to maintain the combustion state. At the time of startup or partial load when the air flow rate or the fuel flow rate changes, the amount of water that can be added to the air is extremely small.

It is an object of the present invention to add a large amount of moisture to air without deteriorating combustion stability even at the time of start-up or partial load in which the air flow rate or the fuel flow rate changes, so as to cover a wide load band. To provide a gas turbine combustor which is excellent in thermal efficiency and emits less NOx.

[0005]

A first feature of a gas turbine according to the present invention for achieving the above object is that a system for branching air discharged from a compressor and adding a large amount of water thereto, A pilot burner that performs diffusion combustion operated using only moisture-free or low-moisture-concentration air by providing a system that does not load moisture or adds moisture only at a low concentration of about 5% by weight; It is to constitute a combustor by combining a burner operated by air to which a large amount of moisture has been added.

Accordingly, the pilot burner performs diffusion combustion using air that does not contain moisture or has a low moisture concentration. Therefore, there is an adverse effect on combustion stability such as a decrease in combustion speed and a decrease in flame temperature due to the mixture of moisture. And stable combustion can be performed.

A second feature is that each air and flame from a burner operated by air to which a large amount of moisture is added can flow into the downstream side of the flame of the pilot burner. It is to arrange the burner.

[0008] With this configuration, the air and the flame from the burner operated by the air to which a large amount of water has been added flow into the downstream part of the flame of the pilot burner, so that the flame that governs the stability of the flame of the pilot burner is controlled. At the base, only air and fuel containing no water or having a low water concentration are present, and a state where stable diffusion combustion can be performed can be maintained. In addition, since the air and flame from the burner operated by air with a large amount of moisture flow into the high-temperature combustion gas in the downstream part of the flame of the pilot burner, the amount of heat generated by the flame of the pilot burner can be effectively increased. It is possible to transfer to a burner operated by air to which moisture has been added.

A third feature is that when the gas turbine having the first feature is operated, the output of the turbine is reduced by the compressor.
There is an operation method in which the concentration to which water is added is limited to a low level until a point in time when the power for driving equipment necessary for operating a gas turbine including a generator and the like is balanced, that is, a point in time when the no-load operation ends.

Further, in the gas turbine having the first feature, an operation method is employed in which only the pilot burner operated by air having no or low moisture concentration is burned until the end of the no-load operation. May be.

If this operation method is adopted, it is possible to perform combustion only with air having a low moisture concentration at the time of start-up in which the change in air flow rate and fuel flow rate is large and the change in air temperature is large. And a gas turbine with excellent response and quick response can be obtained.

Further, a fourth feature of the present invention is that when air to which a large amount of moisture is added is heated by a regenerator, a plurality of outlets for extracting air from the regenerator are provided, and the air containing a large amount of moisture is provided. Part or all of the gas can be supplied to the combustor at a low temperature, and when the combustion is performed using only the pilot burner, low-temperature air containing a large amount of moisture can be supplied to the downstream side of the flame of the pilot burner. It is to lead to flow into.

In the gas turbine having the first and second characteristics, while only the pilot burner is burning, the air supplied to the burner operated by the air with a large amount of moisture is supplied to the midway of the regenerator. An operation method using low-temperature air extracted from the air may be adopted.

By employing this configuration, when combustion is performed using only the pilot burner, low-temperature air containing a large amount of water can be caused to flow into the downstream side of the flame of the pilot burner. Immediately after completion, it becomes possible to rapidly lower the combustion gas temperature, and NOx generated by diffusion combustion of the pilot burner is fixed and re-decomposed without being discharged, so even during startup or partial load operation NOx emissions can be kept low.

According to a fifth aspect of the present invention, in the gas turbine having the above-described first and second aspects, combustion is performed from a state in which only the pilot burner is burned to a burner operated by air to which a large amount of moisture has been added. In the operation method, when shifting to the state in which the ignition is started, the fuel supplied to the pilot burner is temporarily increased to perform ignition.

With this, when igniting a burner operated by air to which a large amount of water has been added, the fuel supplied to the pilot burner can be temporarily increased, and the flame of the pilot burner can be expanded. In addition to the higher temperature of the downstream part of the flame, the mixture of fuel / humid air flowing into the downstream part of the flame can be directly ignited, so that good ignition performance can be ensured and a large amount of moisture can be obtained immediately after ignition. Even if combustion of the burner operated by the added air becomes unstable, re-ignition can be efficiently performed from the pilot burner.

According to a sixth aspect of the present invention, there is provided a gas turbine having the fourth aspect, wherein a part of the low-temperature air containing a large amount of extracted moisture is cooled in the combustor and / or the turbine section. It is to utilize it.

As a result, the heat transfer coefficient of the air used as the refrigerant is larger than that of the air containing no water because it contains a large amount of water, and the temperature is low.
High cooling efficiency can be obtained, and as a result, the air flow rate required for cooling can be significantly reduced, and the efficiency can be improved by increasing the amount of air guided to the turbine.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a gas turbine according to the present invention will be described with reference to FIG.

FIG. 1 is a system diagram of the gas turbine plant of the present embodiment. This embodiment is suitable for generating a relatively large amount of power, and includes a compressor 4, a combustor 10, a gas turbine 30, and a generator 31 that take in air from outside the system and compress the air. A post-cooler 11 for cooling air between the compressor and the combustor, and a humidification tower 19 for adding moisture to the air are provided.

The configuration of the gas turbine apparatus having the above-described configuration, which is a feature of the present embodiment, will be described below.

The air 1 sucked from outside the system is supplied to the compressor 4
Accordingly, the air is compressed to a high temperature and a high pressure and discharged as compressor discharge air 5. Of the air discharged from the compressor, the air 8 required for operating the pilot burner is branched at a predetermined flow rate by the branch air flow control valve 6, and is supplied to the combustor 10 without being provided with moisture. Supplied. The compressor discharge air after branching the pilot burner air is cooled in the post-cooler 11 and supplied to the humidification tower 19 as low-temperature high-pressure air 12.

On the other hand, the make-up water 13 is pressurized by the make-up water pump 14, adjusted to a predetermined flow rate by the humidification water flow control valve 16, supplied to the humidification tower 19, sprayed in the humidification tower, and pressurized. By mixing with air, the air 22 is guided to the regenerative heat exchanger 23 as high-pressure, low-temperature, high-humidity air 22. If it is desired to enhance the cooling in the post-cooler 11, a bypass water system may be provided from between the post-cooler and the humidification tower 19 to reach the circulating water line below the humidification tower.

The excess water that has not been given to the air in the humidification tower 19 is collected and used as the circulating water 20 as the circulating water pump 2.
It is pressurized at 1 and merges with makeup water. The regenerative heat exchanger 23 exchanges heat between the supplied high-pressure low-temperature high-humidity air 22 and the turbine exhaust 32 to heat the high-humidity air. The high-humidity air is extracted and supplied to the combustor 10 at a predetermined flow rate as the combustor cooling air 28 by the bleed flow control valve 26 during heating. The extracted high humidity air is further heated and supplied to the combustor 10 as high temperature high humidity air 24.

In the combustor 10, a pilot flame serving as a pilot flame for the entire combustor is formed by the pilot burner air 8 and the pilot burner fuel 9 supplied to the pilot burner. By supplying and burning while mixing the humid air 24 and the high-humidity burner fuel 25, high-pressure and high-temperature combustion gas 29 is generated and sent to the gas turbine 30.

In the gas turbine 30, using the energy of the high-temperature and high-pressure combustion gas, the turbine is rotated to obtain an output, and the generator 31 is rotated to generate power. Combustion gas that has worked by adiabatic expansion in the turbine is heated as high-temperature turbine exhaust 32 in the regenerative heat exchanger 23, and then discharged outside the system as low-temperature exhaust. On the other hand, the combustor cooling air 28 supplied to the combustor 10 cools the outer wall of the combustor and the burner, and then is injected into the combustion gas, mixed with the combustion gas and exhausted.

According to the above-described structure, the pilot flame serving as a pilot flame for the entire combustor uses only high-temperature and low-humidity air supplied without adding moisture and without passing through the post-cooler. Therefore, the flame temperature is high and the burning speed is high, so that the flame stability is good. The above pilot flame has a high flame temperature and therefore a large NOx generation amount. However, as described later, the burner arrangement in the combustor is devised, and a burner using high-humidity air (high-humidity burner) is used. Air or fuel from
If the air mixture flows into the downstream of the pilot flame,
By rapidly lowering the combustion gas temperature, the generated N
It is possible not to provide the residence time necessary for Ox to be immobilized, and it is possible to limit the resulting NOx to a small extent.

Further, since high humidity air is supplied and used at a relatively low temperature as the cooling air for the combustor, the initial temperature of the refrigerant is low in addition to the improvement of the heat transfer coefficient by the provision of moisture. Therefore, the cooling efficiency is expected to be improved, and effective cooling can be expected with a smaller flow rate. In addition, since a flow control valve is used in the branch of the compressor discharge air and the bleeding part from the regenerative heat exchanger, the air flow rate for the pilot burner is increased according to the operating conditions to improve combustion stability. It is possible to perform an operation such as increasing the cooling air flow rate or enhancing the cooling by increasing the cooling air flow rate, thereby enabling an operation with a wider operation range.

Further, an example of the combustor used in the above high humidity gas turbine device will be described with reference to FIGS.
FIG. 2 is a longitudinal section of one of a plurality of can-type combustors constituting the combustor of the gas turbine plant, and the right side in the figure is a downstream end serving as an inlet of the gas turbine. In an actual gas turbine plant, a plurality of such combustors are arranged around a turbine shaft. The combustor includes a combustor liner 201, which is an inner cylinder constituting a combustion chamber, inside a combustor outer cylinder 401, which is a pressure vessel that stores the entire combustor, and performs diffusion combustion at the center of its upstream end. Fuel injection nozzle 1
02. FIG. 3 is a view of a cross section of the combustor as viewed from the downstream side. In the combustor shown in this embodiment, the burner located at the center is a pilot burner operated by high-temperature, low-humidity air, and four high-humidity burners using high-temperature, high-humidity air are provided around the burner. In this configuration, the entire combustor is cooled by relatively low-temperature high-humidity air.

The high-temperature and low-humidity air branched from the compressor discharge air passes through the low-humidity air flow path 101 and passes through the swirler 103.
As a result, the required turning for flame stabilization is given,
It is jetted into the combustor and forms a circulating flow inside the pilot flame guide tube 104. The pilot burner fuel is injected into the circulating flow from the nozzle at the tip through the pilot burner fuel supply pipe 102 and ignited to form a pilot flame.

On the other hand, the highly humidified air to which a large amount of water has been applied and which has been heated to a high temperature by the regenerative heat exchanger passes through the highly humidified air passage 105 and is circulated by the humidified burner swirler 107. Then, the swirl necessary for mixing the high-humidity burner fuel and the high-humidity burner fuel is jetted to the high-humidity burner guide tube 108. The high-humidity burner fuel is supplied to the high-humidity burner guide tube 1 from the nozzle at the tip of the supply tube via the high-humidity burner fuel supply tube 106.
08 and mixed with the high humidity air by the swirling given to the high humidity air.

The fuel / humidity air mixture thus formed passes through the high-humidity burner guide tube 108,
The flame is introduced into the wake of the aforementioned pilot flame and forms a flame having a low flame temperature and a low burning speed. Further, the combustor cooling air extracted from the middle of the regenerative heat exchanger is introduced to the outer periphery of the lowermost portion of the combustor through the low-temperature and high-humidity air introduction passage 403 for cooling, and the flow of the combustion gas inside the combustor is reduced. Flows in the opposite direction to convectively cool the combustor transition piece, and the combustor liner 201
To the outer circumference.

A film cooling hole 202 for protecting the inner wall of the combustor liner is opened in the combustor liner, and the combustor cooling air is introduced into the combustor sequentially from the cooling hole 2 on the downstream side while the combustor cooling air flows upstream. At the end or around the high-humidity burner guide tube 108, cooling is performed, and finally, the fuel is ejected from the burner cooling slot 109 into the combustor. Next, an operation method when the operation method according to the present invention is adopted in the gas turbine plant having the above configuration will be described with reference to FIGS. 4 and 5.

FIG. 4 shows the gas turbine load on the horizontal axis.
The fuel flow supplied to the pilot burner and the high-humidity air-using burner (humidifying burner) is shown as a ratio to the rated fuel flow. As shown in FIG.
Since an axial load such as a compressor and a generator is connected to the gas turbine plant, the output that can be taken out from the power generation end does not become positive unless the turbine output exceeds a certain level. The point at which the output of the gas turbine is balanced with the power for driving the components required for operating the gas turbine, including the compressor and the generator, is defined as a no-load point (turbine load = 0). Until the no-load condition is reached,
Compressor (gas turbine) during startup and acceleration operation from ignition
This is an operation region in which the air flow rate changes greatly in accordance with the rotation speed of, and combustion stability is most required from the viewpoint of plant operation.

In the operation region where the turbine load is negative, the plant is started and accelerated by performing combustion using only a pilot burner that performs diffusion combustion using high-temperature, low-humidity air having the highest combustion stability. After reaching the no-load point, the burner using the high humidity air (humidifying burner) is sequentially ignited and operated. In order to ignite the humidifying burner, it is necessary to provide the fuel / high-humidity air mixture with large heat capacity with the energy required for ignition. First, increase the diffusion fuel of the pilot burner to achieve a state that bears some turbine load. (Turbine load a%), and at the same time, supply of fuel to the humidifying burner is started.

By performing such an operation, the flame of the pilot burner expands to the downstream side, and it is possible to raise the temperature of the portion where the fuel / high-humidity air mixture flows from the humidifier burner. Stable ignition can be performed.
When the ignition is completed and the fuel flow rate of the humidification burner reaches a certain level or more, the flame can be maintained by the heat generated by the humidification burner flame itself, so even if the flow rate of the pilot burner is reduced,
There is no loss of combustion stability throughout the combustor (turbine load b%).

In this embodiment, of the four humidifying burners,
At first, only the two igniters are ignited, and when the load reaches a certain level (turbine load d%), the remaining two humidifying burners are ignited. In such an operation method, the flow rate of the fuel supplied to each humidifying burner can be limited to a flow rate range of a certain level or more, so that the controllability of the burner is good.

In this case, in addition to the pilot burner flame, heat can be expected to be supplied from the flames of the two humidified burners that have already been ignited and operated. Since a certain amount of fuel flow can be secured from the beginning, it is not necessary to increase the pilot burner fuel.

FIG. 5 shows the gas turbine load on the horizontal axis in the same manner as above, and shows the amount of water added to the air at that load point as a ratio to the rated amount of addition. In this embodiment,
As shown in the system diagram of FIG. 1, the pilot burner air is supplied without passing through the humidification tower, so that the added humidity of the pilot burner air is 0% at any load. In the operating range up to the no-load point where the changes in air flow rate and fuel flow rate are large, flame stability is particularly required, so only high-temperature, low-humidity air supplied without a post-cooler or humidification tower is required. Operate only with the pilot burner operated by.

After reaching the no-load point, the burner (humidified burner) utilizing high humidity air is sequentially fired and the addition of moisture is started. At the beginning of the ignition of the humidifying burner, the amount of heat supplied to the combustor is relatively small. Therefore, if the added moisture is excessive, the heat capacity of the fuel / high humidity air mixture to be ignited increases, and It is not possible to heat to the required temperature and there is a risk of flame loss (misfire).

According to the operating method according to the present invention, when the humidification burner is started to start adding moisture to the humidification burner air (turbine load a% to b%), the pilot burner fuel is increased and the pilot flame is increased. Since it is large, a sufficient supply of heat can be expected, and the rate of adding moisture can be set high. In this embodiment, of the four humidifying burners,
An operation method that ignites only the book (humidifying burner) is adopted. After the ignition of the humidifying burner is completed and the flame is stabilized, the amount of added moisture can be increased to lower the combustion gas temperature.

In the pilot burner, diffusion combustion is performed from the viewpoint of ensuring combustion stability. Therefore, combustion is performed at a stoichiometric mixture ratio on the flame surface where the reaction proceeds, and there is a disadvantage that the amount of NOx generated is large. Since NOx decomposes if it does not stay in a high temperature atmosphere of a certain degree or more, after stable combustion is secured in the entire combustor, it is better to actively apply moisture to lower the combustion gas temperature to reduce NOx. Is advantageous.

Therefore, an operation for rapidly increasing the amount of added moisture is performed during the turbine load b% to c% when the ignition of the humidifying burner is completed and the flame is stabilized. At this time, if the moisture is added excessively, the temperature of the combustion gas is excessively lowered, and the flame stability of the humidifying burner may be impaired. Therefore, an operation in which the moisture addition is kept constant at a certain level is adopted.

Thereafter, when the turbine load reaches d% and the combustion load of a single burner exceeds a certain level, the remaining two humidification burners (humidification burners) are ignited.
Since a sufficient amount of combustion has already been secured, it is not always necessary to increase the amount of combustion of the pilot burner here.
When all four humidifying burners are ignited and the flame stabilizes, heat is generated uniformly throughout the combustor, and the flames of the humidifying burners supply heat to each other, improving flame stability and further increasing moisture. Can be loaded.

Another embodiment of the gas turbine according to the present invention will be described with reference to FIG.

FIG. 6 is a system diagram of a gas turbine plant according to another embodiment. This embodiment is a configuration suitable for generating a relatively small amount of power. The overall configuration includes a compressor 4, a combustor 10, a gas turbine 30, and a generator 31 that take in air from outside the system and compress it, as in the previous embodiment, and discharge air from the compressor to the compressor and the combustor. A post-cooler 11 for cooling in the middle and a humidification tower 19 for adding moisture to the air are provided.

The air 1 sucked from outside the system is first supplied with a slight amount of moisture of a few percent by the inlet humidifier 2 and sent to the compressor 4 as low-humidity air 3. And is discharged as compressor discharge air 5. Of the air discharged from the compressor, the air 8 required for operating the pilot burner is branched at a predetermined flow rate by the branch air flow rate setting orifice 7.
It is supplied to the combustor 10. Unlike the above-described embodiment, the branch flow rate is set by the orifice, and thus becomes a fixed flow rate. The compressor discharge air after branching the pilot burner air is cooled in the post-cooler 11 and supplied to the humidification tower 19 as low-temperature high-pressure air 12.

On the other hand, the make-up water 13 is pressurized by the make-up water pump 14 and is supplied by the inlet humidification spray water flow control valve 15.
After branching the inlet humidifier spray water 17 sent to the inlet humidifier 2, the humidifier spray water 17 is adjusted to a predetermined flow rate by the humidification water flow control valve 16 and supplied to the humidification tower 19. The humidification water supplied into the humidification tower is sprayed and mixed with high-pressure air, and is guided to the regenerative heat exchanger 23 as high-pressure / low-temperature high-humidity air 22. The excess water that has not been given to the air in the humidification tower 19 is collected, and the pressure is increased by the circulating water pump 21 as the circulating water 20, and merges with the makeup water.

If it is desired to enhance the cooling in the post-cooler 11, a bypass water system may be provided between the post-cooler and the humidification tower 19 to reach the circulating water line below the humidification tower. Further, in order to secure the humidification amount of the inlet humidifier, a system may be provided in which the amount of water supplied to the inlet humidifier is sufficiently larger than the humidification amount, water is collected from the bottom of the humidifier, and merged with the circulating water. . In the regenerative heat exchanger 23, heat exchange is performed between the supplied high-pressure low-temperature high-humidity air 22 and the turbine exhaust 32,
Heat high humidity air.

The high-humidity air has a bleed air flow rate of 27 during heating.
As a result, air is extracted and supplied to the combustor 10 with the flow rate at a predetermined ratio as the combustor cooling air 28. The extracted high humidity air is further heated and supplied to the combustor 10 as high temperature high humidity air 24. In the combustor 10, a pilot flame serving as a pilot flame for the entire combustor is formed by the pilot burner air 8 and the pilot burner fuel 9 supplied to the pilot burner. The fuel 24 and the high-humidity burner fuel 25 are supplied and burned while being mixed, so that a high-pressure and high-temperature combustion gas 29 is generated and sent to the gas turbine 30.

The gas turbine 30 uses the energy of the high-temperature, high-pressure combustion gas to rotate the turbine to obtain an output, and to rotate the generator 31 to generate power. Combustion gas that has worked by adiabatic expansion in the turbine is heated as high-temperature turbine exhaust 32 in the regenerative heat exchanger 23, and then discharged outside the system as low-temperature exhaust. On the other hand, the combustor cooling air 28 supplied to the combustor 10 cools the outer wall of the combustor and the burner, and then is injected into the combustion gas, mixed with the combustion gas and exhausted.

Further, an example of a combustor used in the above high humidity gas turbine device will be described with reference to FIGS. 7 and 8. FIG.
FIG. 7 is an upper half of a longitudinal section of an annular combustor arranged in an annular shape around a turbine shaft in the above gas turbine plant, and the right side in the figure is a downstream end serving as an inlet of the gas turbine. The combustor includes a combustor liner 201, which is an inner ring constituting a combustion chamber, inside a combustor outer ring 401, which is a pressure vessel that stores the entire combustor, and performs diffusion combustion around the upstream end thereof. It has a fuel injection nozzle 102. FIG. 8 is a view of a cross section of the combustor as viewed from the downstream side. In the figure, the whole annular combustor is shown small in the lower left,
Of these, the upper 60 ° is shown larger. In the combustor shown in the present embodiment, the burner located in the center of the annular combustion chamber is a pilot burner operated by high-temperature and low-humidity air, and a high-humidity burner that uses high-temperature and high-humidity air on the downstream side. The upper and lower two combustors are used to cool the entire combustor with relatively low-temperature high-humidity air.

The high-temperature, low-humidity air branched from the compressor discharge air passes through the low-humidity air flow path 101 and passes through the swirler 103.
As a result, the required turning for flame stabilization is given,
The fuel flows into the combustor to form a circulating flow inside the combustion chamber. Pilot burner fuel is injected into the circulating flow from a nozzle at the tip through a pilot burner fuel supply pipe 102 and ignited to form a pilot flame.

On the other hand, the high-humidity air to which a large amount of water has been applied and which has been heated to a high temperature by the regenerative heat exchanger passes through the high-humidity air flow path 105 and blows out to the high-humidity burner guide tube 108. The high-humidity burner fuel is jetted from the nozzle at the tip of the supply pipe to the high-humidity burner guide pipe 108 via the high-humidity burner fuel supply pipe 106 and mixed with the high-humidity air. The fuel / humidity air mixture thus formed is:
Through the high-humidity burner guide tube 108, it is introduced into the downstream part of the pilot flame, and forms a flame having a low flame temperature and a low burning speed. With this configuration, the fuel / humidified air mixture introduced into the downstream of the pilot flame collides at the center of the combustor, and forms a large-scale circulating flow to promote flame holding and mixing. Therefore, combustion stability is high, and combustion gas having a uniform temperature distribution at the outlet of the combustor is easily obtained.

The combustor cooling air extracted from the middle of the regenerative heat exchanger is supplied to the low-temperature high-humidity air introducing passage 40 for cooling.
3, is introduced to the outer periphery of the most downstream portion of the combustor, flows in a direction opposite to the flow of the combustion gas inside, and flows through the combustor liner 2.
01 Outer circumference. A film cooling hole 202 for protecting the inner wall of the combustor liner is opened in the combustor liner, and the combustor cooling air is introduced into the combustor sequentially from the cooling hole 2 on the downstream side and reaches the upstream end of the combustor. Finally, the fuel is ejected from the burner cooling slot 109 into the combustor.

Next, an operation method in the case of employing the operation method according to the present invention in the gas turbine plant having the above configuration will be described with reference to FIGS.

FIG. 9 shows the flow rate of the fuel supplied to the pilot burner and the high-humidity air-using burner (humidifying burner) as a ratio to the rated fuel flow rate with respect to the gas turbine load on the horizontal axis as in FIG. It is.

In this embodiment, since the inlet humidifier is provided, when humidification is started, about several% of moisture is added to all supplied air. In the operating state where combustion stability is required until reaching the no-load state, the plant is started up by performing combustion with only the pilot burner that performs diffusion combustion using high-temperature air branched from the compressor outlet without performing humidification.・ Raise the speed. After reaching the no-load point, the burner (humidified burner) using high humidity air is ignited and operated. In order to ignite the humidifying burner, it is necessary to provide the fuel / high-humidity air mixture with large heat capacity with the energy required for ignition. First, increase the diffusion fuel of the pilot burner to achieve a state that bears some turbine load. (Turbine load a%), and at the same time, supply of fuel to the humidifying burner is started.

By performing such an operation, the flame of the pilot burner expands to the downstream side, and it is possible to raise the temperature of the portion where the fuel / humidified air / air mixture from the humidifying burner flows. Stable ignition can be performed.
When the ignition is completed and the fuel flow rate of the humidification burner reaches a certain level or more, the flame can be maintained by the heat generated by the humidification burner flame itself, so even if the flow rate of the pilot burner is reduced,
There is no loss of combustion stability throughout the combustor (turbine load b%). Thereafter, the fuel flow rate is gradually increased to reach the rated load.

FIG. 10 shows the gas turbine load on the horizontal axis, as in FIG. 5, and shows the amount of water added to the air at that load point as a ratio to the rated added amount. In this embodiment, the inlet humidifier is provided as shown in the system diagram of FIG. 6, so that when humidification is started, about several percent of moisture is added to all supplied air. In the operating range up to the no-load point where the changes in air flow rate and fuel flow rate are large, flame stability is particularly required, so only high-temperature, low-humidity air supplied without a post-cooler or humidification tower is required. Operated only by the pilot burner operated in, and humidification is not performed by the inlet humidifier. After reaching the no-load point, the high-humidity air-using burner (humidifying burner) is ignited and the addition of moisture is started.

At the beginning of the ignition of the humidifying burner (turbine load a%
Ｂb%), since the amount of heat supplied to the combustor is relatively small, if the added moisture is too large, the heat capacity of the fuel / high-humidity air mixture to be ignited becomes large, which is necessary for ignition. Heating to an unusually high temperature, resulting in the risk of flame loss (misfire).

Therefore, the humidification at this time is performed only by humidifying the entire air supplied to the combustor using only the inlet humidifier. After the ignition of the humidification burner is completed and the flame is stabilized, it is possible to reduce the combustion gas temperature by increasing the amount of added moisture.

In the pilot burner, diffusion combustion is performed from the viewpoint of securing combustion stability. Therefore, combustion is performed at a stoichiometric mixture ratio on the flame surface where the reaction proceeds, and there is a disadvantage that the amount of NOx generated is large. Since NOx decomposes if it does not stay in a high temperature atmosphere of a certain degree or more, after stable combustion is secured in the entire combustor, it is better to actively apply moisture to lower the combustion gas temperature to reduce NOx. Is advantageous. Therefore, an operation for rapidly increasing the amount of added moisture is performed during the turbine load b% to c% in which the ignition of the humidifying burner is completed and the flame is stabilized.

[0064]

According to the present invention, a pilot burner for performing diffusion combustion which is operated using only air having no moisture or a low moisture concentration, and a pilot burner are arranged so as to flow into the downstream part of the flame. Combustors are constructed by combining burners operated by air with a large amount of water added, and the air flow and fuel flow change by controlling the fuel flow and water addition to be shared by the humidifying burner according to the load. Even at the time of start-up or partial load, by adding a large amount of water to the air without deteriorating combustion stability, a gas turbine combustor with excellent thermal efficiency over a wide load band and low NOx emission is realized. Can be provided.

Further, by extracting a part of the low-temperature air containing a large amount of moisture and utilizing it for cooling the combustor and / or the turbine section, cooling with higher cooling efficiency becomes possible, and the cooling Can reduce the amount of air
As a result, the efficiency of the entire gas turbine can be improved.

[Brief description of the drawings]

FIG. 1 is a system diagram of a gas turbine plant according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a gas turbine combustor according to one embodiment of the present invention.

FIG. 3 is a cross-sectional view of the gas turbine combustor of FIG. 2;

FIG. 4 is a characteristic diagram showing an example of a method of controlling a fuel flow rate when implementing a gas turbine according to the present invention.

FIG. 5 is a characteristic diagram showing an example of a method for controlling the amount of moisture added to air when implementing the gas turbine according to the present invention.

FIG. 6 is a system diagram of a gas turbine plant according to another embodiment of the present invention.

FIG. 7 is a longitudinal sectional view of a gas turbine combustor according to another embodiment of the present invention.

FIG. 8 is a cross-sectional view of a gas turbine combustor according to another embodiment of the present invention.

FIG. 9 is a characteristic diagram showing an example of a fuel flow control method when implementing a gas turbine according to another embodiment of the present invention.

FIG. 10 is a characteristic diagram showing an example of a method for controlling the amount of water added to air when implementing a gas turbine according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Air, 2 ... Inlet humidifier, 3 ... Low humidity air, 4 ... Compressor, 5 ... Compressor discharge air, 6 ... Branch air flow control valve, 7
... orifice for setting branch air flow, 8 ... air for pilot burner, 9 ... fuel for pilot burner, 10 ... combustor,
11 ... post-cooler, 12 ... high-pressure, low-temperature, low-humidity air, 13 ...
Make-up water, 14 ... make-up water pump, 15 ... inlet humidification spray water flow control valve, 16 ... humidification water flow control valve, 17 ... inlet humidification spray water, 18 ... humidification spray water, 19 ... humidification tower , 20 ...
Circulating water, 21 circulating water pump, 22 high-pressure low-temperature high-humidity air, 23 regenerative heat exchanger, 24 high-pressure high-temperature high-humidity air,
25: fuel for humidified air burner, 26: bleed flow control valve, 27: cooling air bleed flow setting orifice, 28 ...
Combustor cooling air, 29 combustion gas, 30 turbine, 3
1: generator, 32: turbine exhaust, 33: low temperature exhaust, 1
01: Low humidity air flow path, 102: Fuel supply pipe for pilot burner, 103: Swirler, 104: Pilot burner flame guide pipe, 105: High humidity air flow path, 106: Fuel supply pipe for high humidity burner, 107 ... High humidity burner swirler,
108: high humidity burner guide tube, 109: burner cooling slot, 201: combustor liner, 202: film cooling hole, 301: combustor tail tube, 401: combustor outer tube, 40
2 ... Combustor transition tube flow sleeve, 403 ... Cooling low-humidity air introduction passage.

Claims (6)

[Claims] 1. A system for branching air discharged from a compressor and adding a large amount of water and a system for adding water only when the water is not loaded or only at a low concentration are provided. A gas turbine characterized in that a combustor is configured by combining a pilot burner that performs diffusion combustion operated using only low-temperature air and a burner that is operated using air to which a large amount of moisture has been added. 2. The gas turbine according to claim 1, wherein
The combustor in which the burners are arranged so that air and flame from a burner operated by air with a large amount of moisture can flow into the downstream side of the flame of the pilot burner. A gas turbine characterized by the above. 3. The operation of the gas turbine according to claim 1, wherein an output of the turbine is a power for driving equipment necessary for operating the gas turbine, including a compressor and a generator. A gas turbine characterized by an operation method in which the concentration for adding moisture is limited to a low level until a point in time when the operation is balanced, that is, a point in time when the no-load operation ends. 4. When the air to which a large amount of moisture is added is heated by a regenerator, a plurality of outlets for extracting air from the regenerator are provided, and a part or all of the air containing a large amount of moisture is cooled at a low temperature. So that it can be supplied to the combustor in a state,
A gas turbine having a flow path arranged so as to guide low-temperature air containing a large amount of moisture into a flame of a pilot burner when combustion is performed only by the pilot burner. 5. The gas turbine according to claim 1, wherein when shifting from a state in which only the pilot burner is burned to a state in which a burner operated by air to which a large amount of moisture is added starts combustion. A gas turbine, which is an operation method in which ignition is performed by temporarily increasing fuel supplied to a pilot burner. 6. The gas turbine according to claim 4, wherein
A gas turbine comprising a flow path for guiding a part of low-temperature air containing a large amount of extracted water to a cooling flow path of a combustor or a turbine section.