JP3139978B2 - Gas turbine combustor - Google Patents

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 for performing premix combustion using gaseous fuel or liquid fuel.

[0002]

2. Description of the Related Art In general, NOx generated during combustion includes fuel NO generated from nitrogen compounds in fuel.
x and thermal NOx generated from nitrogen in the air. Technologies for reducing fuel NOx include:
There is a method in which a reduction region is formed in the combustion region to reduce NOx to N2 and O2, but basically, it is most effective to reduce the nitrogen content in the fuel, that is, to reform the fuel. .

On the other hand, techniques for reducing thermal NOx include a water injection method, an exhaust gas recirculation method, a lean fuel combustion method, and the like. Although these methods reduce the thermal NOx mainly by lowering the flame temperature, the use of these methods tends to reduce the flame stability.

Usually, as a combustion method in a combustor, so-called diffusion combustion in which fuel and air are ejected from different nozzles has been mainly used, but recently, the same burner is prepared by mixing fuel and air in advance. Premixed combustion spouting from is being used.

[0005] The advantages of using premixed combustion are mainly the following two points.

On the one hand, the use of premixed combustion makes it possible to reduce the reaction zone of combustion. In other words, since the gas ejected from the burner is already a premixed gas of fuel and air, there is no need for an area for forming the premixed gas downstream of the burner, the flame can be shortened, and the high load It is possible to burn.

Another is that thermal NOx can be reduced. In diffusion combustion in which fuel and air are ejected from different nozzles into a combustion chamber, the air ratio is 1 (theoretical mixture ratio) in the process of mixing fuel and air in the combustion chamber even if the fuel is burned under lean conditions. It is generally considered that it is difficult to reduce NOx because there is always a nearby area. In contrast, in the fuel-lean premixed combustion method in which excess air and fuel are mixed in advance and burned, NOx can be easily reduced because fuel is burned under lean combustion conditions in all combustion regions. is there.

[0008] Such a lean premixed combustion method, for example,
It is being adopted in a gas turbine combustor described in Japanese Patent Publication No. 62-35016.

Although lean premixed combustion is combustion with excess air, the flame temperature is lowered and NOx can be reduced.
The disadvantage is that the stability of the premixed flame is poor.

[0010] In order to improve the stability of the premixed flame, it is necessary to form a flame near the stoichiometric mixture ratio, but combustion near the stoichiometric mixture produces a large amount of NOx as described above.

As described above, the conditions under which a stable flame is easily formed and the conditions under which the generation of NOx can be suppressed are different from each other. Even if this is done, a combustion technique that can reduce NOx is required.

Conventionally, as a technique for stabilizing a premixed flame, for example, there are combustors described in US Pat. No. 4,051,670 and US Pat. No. 4,150,539.

The former combustor includes a swirling means for swirling a gas mixture of air and fuel in the combustion chamber, and a pressure reducing means for reducing the pressure in a part of the area where the swirling flow is formed. By guiding the high-temperature combustion gas into the swirling flow of the gas, the ignitability of the fuel is ensured and the flame is stabilized.

In the latter combustor, a resistance plate is provided at an outlet of a mixed gas of air and fuel, and a high-temperature combustion gas formed downstream of the resistance plate serves as an ignition source to stabilize the flame. It is to let.

[0015] In addition, as disclosed in Japanese Patent Application Laid-Open No. 59-74406, there are ones using a pilot flame,
As described in JP-A 64-54122,
There are many techniques for stabilizing a flame, such as those that create a swirling flow.

In each of these techniques, a mixed region of the combustion gas and the premixed gas is hardly formed due to the influence of the shape of the combustion chamber and the swirling flow.

[0017]

When lean premixed combustion is performed by using the above-described flame stabilization technique, the premixed flame is stabilized and a certain amount of NOx can be reduced.

However, in recent years, emission regulations for NOx, which causes photochemical smog, have become stricter year by year, and a technology capable of reducing NOx has been desired.

An object of the present invention is to pay attention to such a point. A gas turbine combustor capable of obtaining a stable flame at the time of premixed combustion and further reducing NOx can be obtained. It is to provide.

[0020]

According to a first aspect of the present invention, there is provided a gas turbine having a premixed burner for injecting a premixed gas in which fuel and air are premixed into a combustion chamber. In the combustor, a pilot burner is disposed substantially at the axial center of the combustion chamber, and respective ejection ports of the plurality of premix burners are spaced from each other around the pilot burner and are disposed at regular intervals . The plurality of premix burners each have a fuel nozzle for ejecting the fuel into the premix burner, and the plurality of premix burners and the pilot burner each have a direction in which a gas ejected from the combustion chamber is ejected. Is characterized by being parallel to the central axis.

Here, in the first gas turbine combustor, the plurality of injection ports are formed around the burner.
They may be arranged on the same circumference .

According to a second aspect of the present invention, there is provided a gas turbine combustor having a premix burner for injecting a premix gas in which fuel and air are premixed into a combustion chamber. A pilot burner is disposed substantially at the axial center of the combustion chamber, and a plurality of the premixing burners are arranged at regular intervals around the pilot burner. The mixing burner has a fuel nozzle for injecting the fuel into the premixing burner, and the plurality of premixing burners and the pilot burner each have an ejection direction of a gas to be ejected and a central axis of the combustion chamber. Parallel and projecting from the downstream side to the upstream side of the plurality of premix burners in the vicinity of the respective outlets and downstream of the outlets. If, is characterized in that as resistors overlaps a portion of 該噴 outlet is installed.

[0023]

In order to reduce thermal NOx with a premixed flame, as described above, combustion has conventionally been mainly performed under excess air conditions. It has been clarified that NOx can be reduced by mixing a part of the combustion gas into the premixed gas before the mixed gas burns.

The present invention has been made based on this finding.

At startup, fuel is injected from the burner,
Form a diffusion flame in the combustion chamber. Diffusion flames can be easily formed because the amount of air to fuel can be easily increased. Therefore, it is possible to easily start the combustor. Next, the premixed gas is ejected from a plurality of ejection ports arranged around the burner.
The premixed gas ejected from the jet port is heated by the heat of the diffusion flame that has already been formed, easily burns, and stabilizes the premixed flame. Since the diffusion flame generates a large amount of NOx, in order to reduce the generation amount of the NOx, the diffusion flame may be reduced at the same time as the premixed flame is formed.

The combustion gas from the diffusion flame reaches the premixed gas ejected from the plurality of ejection ports. This combustion gas is
Mix with the premixed gas to form a combustion mixed gas. As a result, the combustion mixture gas having a low oxygen partial pressure burns, so that NO
The amount of generation of x is reduced.

In the case where the resistor is provided, a circulating flow region is formed downstream of the resistor. A part of the high-temperature combustion gas flows into the circulating flow region, and the premixed gas around the circulating flow region is ignited by the high-temperature combustion gas, and a relatively sharp combustion region is surely formed there. You. In this way, the premixed flame is more stabilized because a relatively sharp combustion zone is reliably formed.

[0028]

EXAMPLES Hereinafter, the seeds of the present invention based on FIGS. 1 23
Examples and Reference Examples will be described. In addition, each species carried Rei及
In the reference examples , the same portions are denoted by the same reference numerals, and redundant description will be omitted.

A first embodiment of the gas turbine combustor will be described with reference to FIGS . As shown in FIG. 3 , the gas turbine combustor 100 includes an air compressor 301 that pressurizes the combustion air 1 and sends it to the combustor 100, and a gas turbine 303 that is driven by the combustion gas 4 generated in the combustor 100. And are connected. A generator 304 is connected to the gas turbine 303.

The gas turbine combustor 100 is shown in FIGS.
As shown in FIG. 2 , an air inlet 11 for taking in the combustion air 1 from the air compressor 301 and a combustion gas outlet 12 for discharging the combustion gas 4 generated by the combustion are formed in the combustor casing 10. ing. In the combustor casing 10, a primary combustion inner cylinder 31 forming the primary combustion chamber 30 and a secondary combustion inner cylinder 21 forming the secondary combustion chamber 20 are provided.
Are provided.

The primary combustion inner cylinder 31 is provided on the surface of the combustor casing 10 facing the combustion gas outlet 12. The primary combustion within cylinder 31, a plurality of pilot burners 34, 34 for injecting primary fuel 2, ..., are arranged at equal intervals on the same circumference. This pilot burner 3
The primary fuel receiving nozzles 32 for receiving the primary fuel 2 are connected to 4, 34,. Primary air supply ports 33, 3 for allowing the combustion air 1 flowing from the air intake 11 to flow into the inner cylinder 31 are provided on the side circumference of the primary combustion inner cylinder 31.
Are formed, and a primary air control valve 35 for adjusting the amount of the inflowing combustion air 4 is provided therein.

The inner cylinder for secondary combustion 21 is the inner cylinder for primary combustion 3
1, a cooling air port 22 for cooling the inner cylinder itself is formed on the side circumference thereof. A plurality of premix burners 2 for ejecting a premix gas 5 of the combustion air 1 and the secondary fuel 3 are provided at an upstream end of the secondary combustion inner cylinder 21.
3, 23, ... are arranged on the same circumference, to form a premix burner group 24. At the downstream ends of the burners 23, 23, ..., secondary air supply ports 25, 25, ... for allowing the combustion air 1 to flow into the burners 23, 23, ..., and secondary fuel nozzles for ejecting the secondary fuel 3. , 26, 26,... Are provided. The secondary fuel nozzles 26, 26,... Are connected to secondary fuel receiving nozzles 27, 27,. The secondary air supply ports 25, 25, ... are provided with secondary air control valves 28, 28, ... for adjusting the amount of the combustion air that flows thereinto.

The diameter of the outer circumference of the premix burner group 24 arranged on the same circumference is smaller than the inner diameter of the secondary combustion inner cylinder 21, and the secondary combustion chamber 20 is located at the outlet of the premix burner 23. It is formed to increase rapidly.

Near the outlet of the premix burner 23, a resistor 40 for circulating the combustion gas 4 generated by the combustion of the gas mixture 5 is provided. The resistor 40 forms an annular shape along the premix burner group 24 as shown in FIG.
Its cross section is V-shaped. The radial width of the annular resistor 40 is formed smaller than the radial width of the premix burner group 24. The resistor 40 having a V-shaped cross section
The apex is provided so as to face the upstream direction. The top portion, the support member 41 for supporting the resistor 40 that is provided.

A transition piece 15 for guiding the combustion gas 4 to the combustion gas outlet 12 of the combustor casing 10 is connected to a downstream end of the secondary combustion inner cylinder 21.

Next, the operation of the combustor according to the first embodiment will be described.

The combustion air 1 pressurized by the air compressor 301 flows into the combustor casing 10 from the air intake 11. The combustion air 1 passes between the combustor casing 10, the transition piece 15, and the secondary combustion inner cylinder 21, and flows from the primary air supply port 33 into the primary combustion inner cylinder 31. Inner cylinder 2 for secondary combustion from supply port 25
1 flows into. Part of the combustion air 1 flows into the secondary inner cylinder 21 from the cooling air port 22 of the secondary inner cylinder 21 for wall cooling.

On the other hand, the fuels 2 and 3 flow into the combustor 100 from the primary fuel receiving nozzle 32 and the secondary fuel receiving nozzle 27, and are ejected from the pilot burner 34 and the secondary fuel nozzle 26.

The fuel used in this embodiment is liquefied natural gas. Liquefied natural gas is a fuel that contains almost no sulfur or nitrogen compounds, generates little SOx or fuel NOx, and is growing in demand in recent years as clean energy.

The primary fuel 2 ejected from the pilot burner 34 reacts with the combustion air 1 to form a diffusion flame in the primary combustion chamber 30.

On the other hand, the secondary fuel jetted from the secondary fuel nozzle 26
The secondary fuel 3 is mixed with the combustion air 1 in a plurality of premix burners 23, 23,.
It is jetted into the next combustion chamber 20.

The premixed gas 5 injected into the secondary combustion chamber 20
As shown in FIG. 2, it is shunted by a resistor 40.
A first circulation flow region 51 through which gas circulates is formed downstream of the resistor 40. Further, a second circulation flow region 52 in which gas circulates is also formed on the outer peripheral side of the resistor 40, that is, on the outer peripheral side of the upstream end in the secondary combustion chamber 21. This circulating flow is formed because the secondary combustion chamber 20 increases rapidly from the outlet of the premix burner 23.

As shown in FIG. 2 , a high-temperature combustion gas 4 of about 2000 ° C. generated by the combustion of the premixed gas 5 flows into the first circulation flow region 51. For this reason, the first circulating flow region 51 has an ignition temperature of the premixed gas 5 of 700 to 800 ° C.
Beyond, and becomes a high temperature region of 1500 ° C. or more, and the premixed gas 5 adjacent to the first circulating flow region 51 reliably burns,
A relatively sharp combustion zone 53 is formed. Therefore,
The premixed flame formed in the secondary combustion chamber 20 is stabilized by obtaining an ignition source of the high-temperature combustion gas 4.

On the other hand, the combustion gas 4 and the premixed gas 5 flow into the second circulating flow region 52 formed on the outer peripheral side of the circular resistor 40, and the combustion gas 4 and the premixed gas 5 are mixed. The mixed gas 6 is formed by mixing. Also, the combustion gas 4 generated in the primary combustion chamber 30 and the premixed gas 5 are mixed on the inner peripheral side of the annular resistor 40 to form a combustion mixed gas 6 having a low oxygen partial pressure.

The flame of the combustion gas mixture 6 is propagated by the flame from the relatively abrupt combustion region 53 and burns to form a slow combustion region 54 outside the relatively abrupt combustion region 53.
In the slow combustion region 54, the combustion mixture gas 6 having a low oxygen partial pressure burns, so that the combustion temperature is low, and the NOx amount generated in this region is extremely small.

In order to form the combustion mixture 6, it is necessary for the flame to propagate from the inside to the outside of the premix gas 5 ejected from the premix burner 23. This means that if the flame ignites from the outside and the flame spreads inside,
This is because the premixed gas 5 burns before mixing with the combustion gas 4, and the combustion mixed gas 6 is not formed.

Here, when the secondary fuel 3, the combustion air 1, and the combustion gas 4 are uniformly mixed and then ejected from the premix burner 23 to form a flame, only a slow combustion region is formed. No stable flame is formed.

The plurality of premix burners 23 are provided in the present embodiment.
As in the example , it is desirable to arrange on the same circumference at the downstream end of the primary combustion chamber 30. Thus, the premix burner 23
Is disposed, the heat of the combustion gas 4 discharged from the diffusion flame formed in the primary combustion chamber 30 causes the premix burner 2
The premixed gas 5 ejected from 3 is ignited more quickly, and the premixed flame is more stabilized.

Further, it is desirable that the radial width of the resistor 40 be smaller than the radial width of the outlet of the premix burner 23 as in the present embodiment . If the width of the resistor 40 is larger than the width of the outlet of the premix burner 23, the first circulating flow region 51 becomes large, and the premixed flame is not held in the vicinity of the resistor 40, and the flame stability decreases. I do.

The combustion gas 4 generated in the combustor 100 is discharged from the combustion gas discharge port 12 and supplied to the gas turbine 303. In the gas turbine 303, the turbine is driven while the high-temperature and high-pressure combustion gas 4 is expanding. The power of the gas turbine 303 is transmitted to the generator 304,
Power generation is performed.

Generally, in recent gas turbine power generation equipment, the combustion gas 4 discharged from the gas turbine 303 is
It is guided to a waste heat recovery boiler and is often used as a heat source for generating steam. A denitration device may be provided in the waste heat recovery boiler. This denitration apparatus removes NOx in the combustion gas 4 by reacting ammonia with the combustion gas 4 on the surface of the solid catalyst. When the combustor 100 according to the present embodiment is used, the amount of generated NOx is reduced, so that the amount of ammonia used in the denitration device can be reduced. The regulation value can be satisfied.

Next, the gas turbine combustor 10 of this embodiment
The operation method 0 will be described with reference to FIGS. 4 and 5 .

At the time of starting the gas turbine 303, as shown in FIG.
A diffusion flame is formed in the primary combustion chamber 30. When the load on the gas turbine 303 reaches a certain load L0%, the amount of the primary fuel 2 is reduced, and the amount of the secondary fuel 3 is increased correspondingly. Allow mixed flame to form. Constant load L0% to maximum load 100%
Until the load changes, the secondary fuel amount 3 is mainly increased to cope with the load change.

As shown in FIG. 4 , the air supply amount is reduced by decreasing the primary air amount in accordance with the increase or decrease of the fuels 2 and 3 so as to keep the NOx generation amount within a certain range . Increase air volume.

In a combustor in which the resistor 40 is not provided, the stability of the premixed flame formed in the secondary combustion chamber 20 depends on the amount of combustion in the diffusion flame formed in the primary combustion chamber 30 and the diffusion flame. Since it is affected by the air ratio and the like, the ratio of the amount of the primary fuel 2 and the amount of the secondary fuel 3 to be charged is limited to a certain range. In the combustor of this embodiment ,
Since there is a mechanism for stabilizing the premixed flame independently, the ratio between the primary fuel 2 amount and the secondary fuel 3 amount can be set arbitrarily, and the fuel supply can be easily adjusted with respect to load fluctuation.
Further, the load variation range can be increased.

Incidentally, in the combustor 100 of this embodiment , the supply of the primary fuel 2 may be stopped after the fuel is switched.
By always charging the secondary fuel 2 into the primary combustion chamber 20 and forming a diffusion flame, it is possible to quickly cope with an increase or decrease in load.

Next, various kinds of combustors have been verified, and the principle of stabilizing the premixed flame and the effect of reducing NOx will be described with reference to FIGS .

In this verification, five types of verification combustors are used.

As shown in FIG. 6 , the first verification combustor 410 includes a premix burner 411, a combustion chamber 412 that rapidly increases from the outlet of the burner 411, and a burner 411.
Pilot burners 413 around the exit of
413,... The gas ejection flow rate from the pilot burner 413 depends on the premix burner 4
It is set to be equal to or less than 1/1000 of the gas ejection flow rate from the eleven.

A pilot flame 414 is formed by the pilot burner 413, and the premix gas 401 ejected from the premix burner 411 is burned using the pilot frame 414 as an ignition source.
The premixed flame 402 is formed in a conical shape from the outlet of the burner 411. On the outer periphery of the premixed flame 402, the combustion gas 4
04 forms an external circulation region 403.

In this combustion, the pilot frame 414
, The premixed flame 402 is stabilized, but since the premixed flame 402 is formed from the outlet of the burner 411 and the tip is not separated, the combustion gas formed around the flame 402 Circulating flow of 404 and premixed gas 4
It can hardly be expected that 01 and 01 are mixed. Therefore, the premixed gas 401 hardly burns in a state of being mixed with the combustion gas 404, so that NOx cannot be reduced much.

A second verification combustor 420 is a combustor according to the present invention, and as shown in FIG.
And a combustion chamber 412 that rapidly increases from the outlet of the burner 411, and a plate-shaped resistor 421 disposed near the outlet of the burner 411.

The premixed gas 401 is ejected from the burner 411. An internal circulation area 422 is formed inside the premixed gas jet by the action of the resistor 421. Further, the external circulation flow region 423 is formed because the combustion chamber 412 is rapidly increased from the outlet of the burner 411.

The internal circulation flow region 422 and the external circulation flow region 4
The formation of 23 is confirmed by measuring the temperature distribution, gas composition distribution, flow velocity distribution, and emission spectrum distribution of OH radicals and the like in the combustion chamber 412.

The high-temperature combustion gas 404 flows into the internal circulation flow region 422, and a relatively sharp combustion region 424 is reliably formed around the internal circulation flow region 422. As described above, since the relatively sharp combustion region 424 is reliably formed, the premixed flame is stabilized.

Further, since the relatively rapid combustion region 424, that is, the region having a high radical concentration, is formed only within a specific narrow range, the region where the decomposition and oxidation of nitrogen in the combustion air is promoted is narrow. In addition, generation of thermal NOx can be suppressed.

Around the relatively sharp burning region 424, the combustion gas 404 in the external circulation flow region 423 and the burner 411
Is mixed with the premixed gas 401 ejected from the mixture to form a combustion mixed gas. The combustion gas mixture is burned by a flame propagating outward from a relatively abrupt combustion region 424 formed inside the jet, and a slow combustion region 42 is formed.
5 is formed. In the slow combustion region 425, combustion proceeds under the condition of low oxygen partial pressure, that is, low radical concentration, so that the amount of generated NOx can be suppressed to an extremely low value.

In this verification combustor 420, NO
In order to reduce x, the combustion gas 404 generated by the combustion of the premixed gas 401 ejected from the premixed burner 411 itself.
Although combustion gas is used, combustion gas generated by combustion of fuel ejected from another burner may be used.

As shown in FIG. 8 , the third verification combustor 430 includes a premix burner 411, a combustion chamber 431 having the same diameter as the burner, and a flat resistor 421.

In the combustion by the test combustor 430,
Similar to the second verification combustor 420, the premixed flame 432 can be stabilized by the action of the resistor 421, but an external circulation region of the combustion gas 404 cannot be formed outside the flame 432. Therefore, NOx cannot be reduced so much.

As shown in FIG. 10 , the fourth verification combustor 440 includes a first premix burner 441 and a burner 4.
41, a second premix burner 442 having an annular ejection port along the side circumference of 41, a plate-shaped resistor 421 arranged near the first premix burner 441, and a second premix burner 442 And a combustion chamber 443 that rapidly increases from the outlet.

The premix gas 401 ejected from the first premix burner 441 forms a stable first premix flame 444 by the action of the resistor 421. The premixed gas 405 ejected from the second premixed burner 442 is supplied to the second premixed flame 445 using the first premixed flame 444 as an ignition source.
To form The second premixed flame 445 is formed at the outlet of the second premixed burner 442 from the boundary with the first premixed burner 441 to almost the end of the first premixed flame 444.

In the combustion by the test combustor 440,
Premix gas 40 ejected from first premix burner 441
Since NO. 1 burns before mixing with the combustion gas 404, NOx cannot be reduced so much.

FIGS. 9 and 11 show the NOx emission characteristics of the above-described verification combustor.

The NOx emission specifying curves 419 and 4 shown in FIG .
Among the curves 29 and 439, a curve 419 is obtained by the first verification combustor 410, a curve 429 is obtained by the second verification combustor 420, and a curve 439 is obtained by the third verification combustor 430. Represents.

The NOx emission characteristic curve 4 shown in FIG.
Of the 29, 448, and 449, the curve 429 was changed by the second test combustor 420, and the curve 449 was changed by the fourth test combustor 440 in the amounts of fuel and air ejected from the two burners. The curve 448 represents the case where the NOx generation amount is the smallest, and the curve 448 represents the case where the NOx generation amount is the largest in the fourth combustor 440.

From these figures, it can be seen that the second verification combustor 42
It can be seen that when 0 is used, the NOx emission can be reduced to 1/3 or less as compared with using another combustor.

Thermal NOx is classified into two types, NOx generated by the Zeldwig mechanism and prompt NOx, in terms of the region where NOx is generated and the generation speed thereof.

The NOx generated by the Zeldwig mechanism is generated at a relatively slow speed after the flame, and is generated by oxidizing nitrogen in combustion air with oxygen. The generation of NOx by the Zeldwig mechanism has a high temperature dependency, and the generation amount increases as the flame temperature increases. When the air ratio, which is the ratio of the amount of input air to the amount of air required to completely burn the fuel, is burned near 1, that is, near the equivalence ratio, the flame temperature becomes highest and the NOx concentration also becomes maximum.

Prompt NOx is specific to hydrocarbon fuels and is NOx generated at a relatively high speed in or near the reaction zone of the flame. Prompt NOx is
Nitrogen in fuel air is decomposed by highly reactive hydrocarbon radicals and the like present in the flame and is further oxidized to form NOx. The generation of the prompt NOx has a relatively low temperature dependency, and is governed by the concentration of radicals having high reaction activity and the size of the region where the radicals with high concentration exist.

Generally, with respect to the combustion air, the amount of prompt NOx tends to increase as the fuel amount increases, and the amount of NOx generated by the Zeldwig mechanism tends to increase as the fuel amount decreases . 11 , it can be seen that the use of the second verification combustor can reduce any NOx. Therefore, the second verification combustor can reduce NOx in both combustion of fuel under the condition of a large air ratio and combustion of the fuel under the condition of a small air ratio. NOx can be sufficiently reduced even without performing this. Further, when the lean premix combustion method is employed, NOx can be further reduced.

In the second verification combustor 420, the fuel is methane, the temperature of the premixed gas to be jetted is about 240 ° C., the air ratio is 1.0 to 1.1 in the combustion chamber, and the combustion air and the fuel are mixed. When only the premixed gas was supplied and completely burned, the emission concentration of NOx was about 60 ppm (0% O2 conversion value) or less.

As shown in FIG. 12 , the fifth verification combustor 450 includes a premix burner 4 having a plurality of annular injection ports.
, 51, 451,..., A flat resistor 452 provided along the burner, and a combustion chamber 453 that increases rapidly from the outlet of the premix burner 451.

The combustor 450 for verification uses a resistor 45 corresponding to each of the premix burners 451, 451,.
2 is provided, but with this configuration,
The premixed gas 40 ejected from the burners 451, 451,...
1 and the combustion gas 404 in the external circulation region 454 can be mixed, and NOx can be reduced.

Next, a second embodiment of the gas turbine combustor will be described with reference to FIG . The gas turbine combustor 110 according to the present embodiment includes a primary combustion chamber 3 that forms a diffusion flame.
0a and a secondary combustion chamber 20a for forming a premixed flame, which has substantially the same basic structure as the combustor 100 of the first embodiment , but includes a premix burner 23 in the secondary combustion chamber 20a. The width D, which rapidly expands from the exit of the vehicle, is increased.

The inner diameter of the secondary combustion inner cylinder 21a is such that the width D where the secondary combustion chamber 20a rapidly expands from the outlet of the premix burner 23 is about 1.5 times the outlet width d of the premix burner 23. It is set to be.

In this embodiment , as in the first embodiment , the first circulating flow region 51 of the combustion gas 4 is formed downstream of the resistor 40, so that a stable premixed flame can be obtained. Can be.

Further, since the width D that rapidly expands from the outlet of the premix burner 23 in the secondary combustion chamber 20a is widened, the second circulating flow region 52a formed on the outer peripheral side of the resistor 40 expands, and the burner 23 Premixed gas 5
And the mixing ratio of the fuel gas and the combustion gas 4 in the second circulation flow region 52a increases. Therefore, since the combustion mixture gas having a low oxygen partial pressure formed by mixing the premix gas 5 and the combustion gas 4 burns more than the simple premix gas 5 burns, the NOx is reduced. Can be reduced.

Further, by increasing the width D that rapidly expands from the outlet of the premixing burner 23, the secondary combustion inner cylinder 22a
Since the combustion air 1 flowing from the cooling air port 22 does not flow directly into the combustion region and lowers the combustion temperature, C
Generation of O and unburned hydrocarbons can be suppressed.

The effect of reducing NOx in the case where the width of the rapid expansion of the combustion chamber from the outlet of the premix burner in the combustion chamber forming the premixed flame was verified, will be described.

For verification, as shown in FIG. 14 , a premix burner 462 and a combustion chamber 461 where a premix flame is formed
And the combustion chamber 460 provided with the resistor 463.

As shown in FIG . 15 , the premix burner 462
As the ratio (D2 / D1) between the diameter D1 of the combustion chamber 461 and the width D2 at which the combustion chamber 461 suddenly expands from the outlet of the premix burner increases, the NOx generation amount decreases. This is because, as D2 increases, the circulating flow 46 formed outside the premixed flame
4 is easily formed, and the oxygen partial pressure in the flame is reduced.

According to the verification result, D2 / D1 is
When it is 1.5 or more, the reduction effect rate of NOx becomes small.
It seems that it is preferable to design so that D2 / D1 is around 1.5.

[0094] Next, based on FIG. 16, a description will be given of a first reference example of a gas turbine combustor.

The combustor 120 includes a combustor casing 121 for forming a premixed flame, a plurality of premixed burners 122, 122,... Arranged in an annular shape, and a plurality of premixed burners 122, 122,. A premix gas supply pipe 123 for supplying the premix gas 5, a plurality of premix burners 122, 1;
, Provided along the resistors 22.

Downstream of the premixed gas supply pipe 123, fuel nozzles 125, 125 for taking in the fuel 2 and air nozzles 126 for taking in the combustion air 1 are provided.

[0097] resistor 124 is formed in a flat plate shape, supported
It is provided on the holding member 128 .

[0098] This reference example is obtained by the verification combustor 450 of the 5 described above in actual level, as in the first embodiment Contact <br/> preliminary second embodiment, stable A premixed flame can be obtained, and generation of NOx can be suppressed. In this embodiment , since two combustion chambers are not provided, the embodiment is excellent in miniaturization as compared with the previous embodiment , but is inferior in that the allowable range for load fluctuation is narrow.

The resistors are used in the first embodiment and the second embodiment.
The cross-section does not need to be V-shaped as in the example , and may be of any shape as long as a circulating flow can be formed on the downstream side. It may be something. According to experiments, in the case of a plate-shaped resistor, the resistor was approximately 45
It has been found that if provided at an angle of inclination within °, the stability of the flame is hardly affected.

Since the resistor is heated to a high temperature, it is necessary to form the resistor from a material having heat resistance of at least 500 ° C. May be supplied to ensure heat resistance.

Next, a second reference example of the gas turbine combustor will be described with reference to FIG .

The gas turbine combustor 130 of this embodiment is
Two combustion chambers forming a premixed flame, a primary combustion chamber 131
And a secondary combustion chamber 141.

The primary combustion chamber 131 is an inner cylinder 1 for the primary combustion chamber.
32, the upstream end of which has the same circumference.
A plurality of primary premix burners are arranged above 133,13
3,... Are provided. Premix burners 133, 13
A plurality of primary fuel nozzles 134, 134,... For ejecting the primary fuel 2 and a primary air supply port 135 for flowing the combustion air 1 into the inner cylinder 132 1
35,... Are provided. The primary combustion chamber 131 is
It is formed so as to increase rapidly at the outlet of the next premix burner 133.

Near the outlet of the primary premix burner 133,
A resistor 136 for circulating the combustion gas 4 generated by the combustion of the premixed gas 5 is provided. Resistor 13
6 is provided on the support member . Secondary combustion chamber 141
Is constituted by a secondary combustion inner cylinder 142, and is provided downstream of the primary combustion inner cylinder 132. At the upstream end of the inner cylinder 142 for secondary combustion, a plurality of secondary premix burners 143, 143,... On the upstream side of the burners 143, 143, ..., secondary air supply ports 145, 145, ... for allowing the combustion air 1 to flow into the burners 143, 143, ... and secondary fuel nozzles for ejecting the secondary fuel 3. 146, 146,... Are provided.

Cooling air ports 138 and 148 for cooling the inner cylinders 132 and 142 themselves are formed on the side circumferences of the primary combustion inner cylinder 132 and the secondary combustion inner cylinder 142.

After the combustion air 1 is compressed by the air compressor 301, the combustion air 1 flows into the combustor 130, and flows into the mixing section 13 of the primary premix burner 133 and the secondary premix burner 143.
At 9,149, it is mixed with fuels 2,3. The premixed gas 5 formed as described above is jetted into the primary combustion chamber 131 and the secondary combustion chamber 141. A part of the combustion air 1 is used for cooling the inner cylinders 132 and 142 as cooling air ports 138 and 1.
48 flows into the combustion chambers 131 and 141.

The premixed gas 5 ejected from the primary premix burner 133 is divided by the action of the resistor 136. A first circulation flow region 151 is formed downstream of the resistor 136, and a premixed flame is formed around the first circulation flow region 151. A second circulating flow region 152 of the combustion gas 4 is formed around the premixed flame. In a premixed flame,
Since the combustion mixed gas formed by mixing the premixed gas 5 and the combustion gas 4 is burned, NOx is reduced.

The combustion gas 4 formed in the primary combustion chamber 131
Goes substantially straight and flows into the center of the secondary combustion chamber 141. A secondary premix burner 143 is provided on the outer peripheral side of the combustion gas 4.
Premixed gas 5 is ejected from the nozzle. Secondary premix burner 1
The premixed gas 5 ejected from 43 is in the primary combustion chamber 131
Is ignited by the combustion gas 4 formed in the step (1) to form a premixed flame.

By providing two combustion chambers as in the present embodiment, the allowable range for load fluctuation can be increased.

Next, a third embodiment of the gas turbine combustor will be described with reference to FIG .

The gas turbine combustor 160 of this embodiment is
Two combustion chambers forming a premixed flame, a primary combustion chamber 131
And a secondary combustion chamber 141, and resistors 161 and 163 are provided at outlets of the respective premix burners 133a and 143.
For other configurations, refer to the second reference
The basic configuration is the same as the gas turbine combustor 130 of the example . The primary combustion resistor 161 has a pilot burner 16 that forms a pilot frame downstream thereof.
2 are provided.

When the combustor 160 is started, fuel is supplied only to the pilot burner 162 and the primary combustion resistor 16
1 to form a pilot frame downstream.

After the pilot frame is formed, 1
The supply of the primary fuel 2 is started from the next premix burner 133a to form a premix flame. After the premixed flame is formed stably, the fuel supply to the pilot burner 162 is stopped. By operating in this manner, the combustor 16
0 can be easily started.

In this embodiment , since the resistors 161 and 163 are provided in each of the premixed burners 133a and 143, any of the premixed flames is not greatly affected by the fuel supply amount or the like. A stable premixed flame can always be obtained.

Next, a fourth embodiment of the gas turbine combustor will be described with reference to FIG . The combustor 170 of the present embodiment includes a premix burner 133 that forms a premix flame in the primary combustion chamber 131 of the combustor 130 of the second reference example.
And a pilot burner (diffusion flame forming burner) 171 for forming a diffusion flame 172 is provided. Other basic configurations are almost the same as those of the second reference example .

When the combustor 170 is started, first, fuel 2 is injected from the pilot burner 171 and the primary combustion chamber 13
1. A diffusion flame 172 is formed in 1. When the diffusion flame 172 is formed, the primary fuel 2 is supplied to the primary premix burner 133 to form a primary premix flame. Primary combustion chamber 13
When the load at 1 becomes a predetermined load, the secondary premix burner 1
The secondary fuel 3 is supplied to 43 and a secondary premixed flame is formed, and the diffusion flame 172 is digested. At this time, 2
The secondary premixed flame is the combustion gas 4 generated by the primary premixed flame.
To ignite.

Thereafter, the loads of the primary premixed flame and the secondary premixed flame are adjusted to cope with the load fluctuation of the combustor 170.

In this embodiment , the start of the combustor 170 can be easily performed. The combustion air 1 for forming the diffusion flame 172 is supplied from around the pilot burner 171. Since the combustion air 1 mixes with the combustion gas discharged from the primary premixed flame, the combustion air 1 is diffused. Flame 1
NOx exhausted from 72 is small.

Next, a fifth embodiment of the gas turbine combustor will be described with reference to FIG .

[0120] The combustor 180 of the present embodiment includes the primary combustion chamber 1
, A plurality of premix burners 183, 183,... Forming a premix flame, and a plurality of premix burners 18
The resistor 184 is disposed in the vicinity of the outlets of 3,183,.
And a pilot burner 185 forming a pilot frame at the center of the upstream end of the primary combustion chamber 181. The secondary combustion chamber 20 and other basic configurations are substantially the same as those of the combustor 100 of the first embodiment. It is what was constituted.

A plurality of primary premix burners 183, 183,
Are arranged on the same circumference . The resistor 184 has a V-shaped cross section and includes a plurality of primary premix burners 183,1.
83, are provided on the downstream side thereof. The primary combustion chamber 181 is constituted by a primary combustion inner cylinder 182, and is formed so as to rapidly expand from an outlet of the primary premix burner 183.

At the time of startup, a pilot flame is formed in the primary combustion chamber 181 by the pilot burner 185. Next, a premixed flame is formed in the primary combustion chamber 181.
When the load reaches a predetermined value, a premixed flame is formed in the secondary combustion chamber 20. Therefore, the pilot burner 18
Since the combustor 180 is started by 5, the start can be easily performed.

In this embodiment , any of the combustion chambers 18
Since the resistors 40 are provided at the outlets of the premixing burners 183 and 23 also in 1 and 20, a stable premixed flame can be obtained. Further, any of the combustion chambers 181, 20
Are also formed so as to rapidly expand from the outlets of the premix burners 183 and 23, so that circulating flow regions 187 and 52 of the combustion gas 4 are formed around the premix flame and NOx
Can be suppressed.

[0124] In the above various Examples and Reference Examples, the arrangement of the plurality of premixed burners, as shown in FIG. 21, a plurality of premix burners 191, 191 are arranged ... to intermittently radially. At this time, the resistor 19 for stabilizing the flame is used.
Are premixed burners 191, 191,.
May be provided radially. In addition,
The combustor 190 shown in the figure is a gas turbine of the fifth embodiment.
FIG. 4 is a cross-sectional view of the burner 170.

In the fifth embodiment , as in the first embodiment , fuel is injected from the pilot burner 185 at the time of startup to form a diffusion flame in the combustion chamber. Diffusion flames can be easily formed because the amount of air to fuel can be easily increased. Therefore, the combustor 190 can be easily started. Next, the premixed gas is ejected from the ejection ports of the plurality of premixed burners 191 arranged around the pilot burner 185. The premixed gas spouted from the spout is warmed by the heat of the diffusion flame already formed,
In addition to burning easily, the premixed flame stabilizes. Since the diffusion flame generates a large amount of NOx, in order to reduce the generation amount of NOx, when the premixed flame is formed,
It is better to reduce the diffusion flame.

The combustion gas from the diffusion flame reaches the premixed gas ejected from the plurality of ejection ports. This combustion gas is
Mix with the premixed gas to form a combustion mixed gas. As a result, the combustion mixture gas having a low oxygen partial pressure burns, so that NO
The amount of generation of x is reduced.

Next, a sixth embodiment of the gas turbine combustor will be described with reference to FIG . Combustor 2 of the present embodiment
Reference numeral 10 denotes a plurality of primary premixing burners 212, 212,... Arranged on the same circumference at the upstream end of the combustion chamber 211.
, A plurality of secondary premix burners 23, 23,... Arranged on the same circumference along the outer circumference thereof, and a secondary premix burner group including an upstream end of the combustion chamber 211. Pilot burner 185 forming pilot frame in center
Are provided. Primary premix burner 21
In the vicinity of the outlets of the second and second premix burners 23, resistors 213 and 40 are provided.

In this embodiment , similarly to the fifth embodiment , a stable premixed flame can be obtained and NOx can be reduced. In the case of the present embodiment , the primary premixed flame and the secondary premixed flame are formed in the same combustion chamber 211, so that the flames overlap each other as in the fourth verification combustor 440. In order to prevent the reduction effect of the NOx reduction and the oscillating combustion, it is necessary to design the primary premix burner 212 and the secondary premix burner 23 with sufficient consideration given to the positional relationship.

Various implementations beyond those connected to the gas turbine
Examples of a gas turbine combustor 100, 110, ..., as shown in FIG. 23
As shown in the figure, by providing a waste heat recovery boiler 312 that generates steam by the heat of the combustion gas 4 from the gas turbine 303 together with the gas turbine 303, a so-called cogeneration system can be constructed.

This cogeneration system comprises an air compressor 301 and gas turbine combustors 100, 110,.
Turbine power generation equipment 310 composed of a gas turbine 303 and a power generator 304, and a main boiler equipment 31
, And a fuel supply facility 315 that supplies fuel 2 to the gas turbine combustors 100, 110,.
, A waste heat recovery boiler 312 and a turbo cooler 314.

The fuel 2 is supplied from the fuel supply facility 315 to the gas turbine combustors 100, 110,.
And supplied to. Gas turbine combustors 100, 110,
Are burned in the combustors 100, 110, and then the combustion gas 4 generated by the combustion is sent to the gas turbine 303. Then, the combustion gas 2 drives the turbine to generate power. The combustion gas 4 from the gas turbine 303 is sent to the waste heat recovery boiler 312,
Then, steam is generated. This steam is used for driving the turbo cooler 314 in summer and used for heating in winter. When the steam is insufficient, the steam generated in the main boiler 313 is used.

Such a cogeneration system is often installed in a city or a suburb where NOx emission regulations are strict, but even in such a case, the amount of NOx emission in the gas turbine combustor is small. As described above, strict regulation values may be satisfied without providing a denitration device in the waste heat recovery boiler 312 in some cases.

By connecting the steam turbine to the waste heat recovery boiler, a waste heat recovery type combined cycle can be configured.

Although the embodiment relating to the gas turbine combustor has been described above, the present invention is not limited to the gas turbine combustor. It may be applied to any combustor, such as a reactor called in a chemical plant or a chemical plant.

[0135]

According to the present invention, the premixed flame is stabilized by the heat of the diffusion flame formed by the combustion of the fuel injected from the burner.

Further, the combustion gas from the diffusion flame is mixed into the premixed gas, and the gas having a low oxygen partial pressure formed thereby burns, so that the NOx can be significantly reduced.

[Brief description of the drawings]

1 is an overall cross sectional view of a gas turbine combustor of the first embodiment according to the present invention.

FIG. 2 is a sectional view of a main part of the gas turbine combustor according to the first embodiment of the present invention.

FIG. 3 is a system diagram of the gas turbine power generation equipment according to the first embodiment of the present invention.

FIG. 4 is a graph showing a relationship between a gas turbine load and an air supply amount when the gas turbine combustor according to the first embodiment of the present invention is operated.

FIG. 5 is a graph showing a relationship between a gas turbine load and a fuel supply amount when operating the gas turbine combustor according to the first embodiment of the present invention.

FIG. 6 is a sectional view of a first verification combustor.

FIG. 7 is a sectional view of a second verification combustor.

FIG. 8 is a sectional view of a third verification combustor.

FIG. 9 is a graph showing NOx emission characteristics of the first, second, and third verification combustors.

FIG. 10 is a sectional view of a fourth verification combustor.

FIG. 11 is a graph showing NOx emission characteristics of second and fourth verification combustors.

FIG. 12 is a sectional view of a fifth verification combustor.

FIG. 13 is an overall sectional view of a gas turbine combustor according to a second embodiment of the present invention.

FIG. 14 is a sectional view of a test combustor.

FIG. 15 is a graph showing NOx emission characteristics of the verification combustor.

FIG. 16 is a sectional view of a main part of a gas turbine combustor according to a first reference example of the present invention.

FIG. 17 is a sectional view of a main part of a gas turbine combustor according to a second reference example of the present invention.

FIG. 18 is a sectional view of a main part of a gas turbine combustor according to a third embodiment of the present invention.

FIG. 19 is a sectional view of a main part of a gas turbine combustor according to a fourth embodiment of the present invention.

FIG. 20 is an overall sectional view of a gas turbine combustor according to a fifth embodiment of the present invention.

FIG. 21 is a gas turbine fuel according to a fifth embodiment of the present invention .
It is a transverse sectional view of the burn unit.

FIG. 22 is an overall sectional view of a gas turbine combustor according to a sixth embodiment of the present invention.

FIG. 23 is a system diagram of a cogeneration system according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Combustion air, 2 ... Primary fuel, 3 ... Secondary fuel, 4 ... Combustion gas, 5 ... Premixed gas, 6 ... Combustion mixed gas, 10 ... Combustor casing, 20, 20a, 141, 222 ... 2 Secondary combustion chamber, 21, 21a, 132, 142 ... Secondary combustion inner cylinder, 23, 133, 133a, 136, 143, 18
3,191,212 ... Premix burner, 30, 30a, 1
31, 181 ... primary combustion chamber, 31, 132, 182 ... 1
Inner cylinder for next combustion, 40, 86, 124, 136, 161,
163, 184, 192, 201, 213: resistor, 5
Reference numeral 1 denotes a first circulation flow region, 52, 52a denotes a second circulation flow region, 53 denotes a relatively sharp combustion region, 54 denotes a slow combustion region , and 100, 110 , 120 , 130 , 160 , and 17
0, 180, 190, 200, 210: gas turbine combustor, 301: air compressor, 303: gas turbine, 3
12 ... Waste heat boiler.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI F23R 3/28 F23R 3/28 D 3/32 3/32 (72) Inventor Norio Arashi 4026 Kuji-cho, Hitachi City, Hitachi, Ibaraki, Ltd. Hitachi, Ltd.Hitachi Laboratory (72) Inventor Tadataka Murakami 4026, Kuji-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd.Hitachi Laboratory Co., Ltd. (72) Inventor Yasuo Yoshii 4026, Kuji-cho, Hitachi City, Ibaraki Prefecture, Hitachi, Ltd. 72) Inventor Kenichi Soma 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi, Ltd.Hitachi Research Laboratory (72) Inventor Hironobu Kobayashi 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd.Hitachi Research Laboratory Co., Ltd. (72) Inventor Ishibashi Yoji 502 Kandate-cho, Tsuchiura-city, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. (72) Inventor Norio Kuroda Hitachi, Ibaraki Prefecture 1-1-1 Sachimachi Hitachi, Ltd. Hitachi Plant

Claims (3)

(57) [Claims] 1. A gas turbine combustor having a premixed burner for injecting a premixed gas in which fuel and air are premixed into a combustion chamber, wherein a pilot burner is disposed substantially at an axial center of the combustion chamber. Each of the premixing burners has a gap with each other around the pilot burner for a certain period.
A plurality of premix burners, each having a fuel nozzle for injecting the fuel into the premix burner; a plurality of the premix burners and the pilot burner;
A gas turbine combustor characterized in that the direction in which each of the gas is jetted is parallel to the central axis of the combustion chamber. 2. The gas turbine combustor according to claim 1, wherein the plurality of injection ports are arranged on the same circumference around the pilot burner. 3. A gas turbine combustor having a premixed burner for injecting a premixed gas in which fuel and air are premixed into a combustion chamber, wherein a pilot burner is disposed substantially at an axial center of the combustion chamber. Each of the premixing burners has a gap with each other around the pilot burner for a certain period.
A plurality of premix burners, each having a fuel nozzle for injecting the fuel into the premix burner; a plurality of the premix burners and the pilot burner;
The ejection direction of each ejected gas is parallel to the central axis of the combustion chamber, and the ejection port is located near each ejection port of the plurality of premix burners and at a position downstream of the ejection port. A gas turbine combustor characterized in that a resistor is provided so as to overlap a part of the ejection port when projected from a downstream side to an upstream side.