JPH0833200B2 - Gas turbine combustor - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a gas turbine combustor in which a catalyst is used to burn fuel, and more specifically, a small amount of nitrogen oxides used in a gas turbine power generation system or the like. It relates to a gas turbine combustor.

[Technical Background of the Invention and its Problems] In recent years, various alternative energies have been required with the depletion of petroleum resources and the like, but at the same time, efficient use of energy resources is also required. Among those that meet these demands are, for example, a gas turbine / steam turbine combined cycle power generation system or a coal gasification gas turbine / steam turbine combined cycle power generation system that uses natural gas as a fuel, which is currently under study.
These gas turbine / steam turbine combined cycle power generation systems have higher power generation efficiency than conventional steam turbine power generation systems that use fossil fuels, and thus natural gas production is expected to increase in the past. It is expected as a power generation system that can effectively convert fuel such as coal and gasification gas into electric power.

Gas turbine combustors used in gas turbine power generation systems have traditionally used mixed gas of fuel and air to
Ignition is carried out using a super plug etc. to carry out homogeneous combustion. An example of such a combustor is shown in FIG. In the combustor shown in FIG. 3, the fuel injected from the fuel nozzle 1 is mixed with the combustion air 3 and ignited by the super plug 2 to burn. Then, the burned gas, that is, the combustion gas, is added with cooling air 4 and dilution air 5, cooled and diluted to a predetermined turbine inlet temperature, and then injected into the gas turbine from a turbine nozzle 6. 8 is a swirler. One of the major problems with such conventional combustors is the large amount of NO when burning fuel.
x is generated to cause environmental pollution.

The reason why the above-mentioned NOx is produced is that at the time of combustion of the fuel, a high temperature part exceeding 2000 ° C. partially exists in the combustor.

In order to solve the problems of the gas turbine combustor as described above, various combustion methods have been studied, and recently, a catalytic combustion method using a solid-phase catalyst has been proposed.

This catalytic combustion method can use a catalyst to burn a lean fuel that does not burn in a normal combustor, and therefore the combustion temperature does not become high enough to generate NOx.
Further, the turbine inlet temperature can be made the same as the conventional one.

FIG. 4 is a conceptual diagram of an example of a combustor used in the catalytic combustion system. The numbers in the figure represent the same elements as in FIG. This combustor is structurally characterized in that the catalyst body 7 is provided on the gas flow path. The catalyst body 7 is usually filled with a combustion catalyst having a honeycomb structure, in which a mixed gas of fuel and air is burned.

Such a gas turbine combustor also has the following drawbacks. That is, in a gas turbine combustor as conventionally considered, the flow rate, flow velocity, fuel concentration, etc. of a mixed gas composed of fuel and an oxidizing gas such as air flowing in the combustor fluctuate due to fluctuations in the connected load. However, the same amount of catalyst must always be reacted and burned. Therefore, when the flow rate of the mixed gas increases, the flow rate increases and contact time with the catalyst body is insufficient, resulting in incomplete combustion. Alternatively, a problem such as misfiring and inability to burn occurs, and conversely, when the flow rate of the gas phase reactant decreases, the flow velocity becomes slower and the contact time between the mixed gas and the catalyst increases correspondingly, and Problems such as partial combustion being completed occur. Then, the temperature of the catalyst body becomes partially high, causing thermal deterioration, destruction, etc., which significantly shortens the life. Further, the high temperature gas generated by the combustion wastefully passes through the catalytic body located further downstream from the catalytic combustion completion point, resulting in an extremely large pressure loss. Therefore, there has been a demand for a gas turbine combustor that can perform stable combustion regardless of changes in the flow rate of mixed gas.

Therefore, the present inventors have previously proposed a catalytic combustion method in which vapor phase combustion downstream of the catalytic body is effectively used to reduce the heat load on the catalytic body (Japanese Patent Application No. 58-229967).

That is, as shown in FIG. 5, the method is a method of first burning a mixed gas of fuel and air by the catalytic body 7. Normally, when a flame-retardant fuel is used in a catalyst body, combustion by catalytic reaction and gas-phase combustion occur at the same time, but in the above proposal, the fuel concentration and temperature of the mixed gas are adjusted so that only combustion by catalytic reaction occurs. , The flow rate is controlled. Therefore, since the catalytic body does not involve gas phase combustion, it does not reach a high temperature, and only part of the fuel burns,
Combustion gas containing unburned fuel is discharged from the catalytic body.

In the above-mentioned proposal, in addition to the exhausted combustion gas, the combustion nozzle 1'provided downstream of the catalyst body 7 shown in FIG.
By adding more fuel, the fuel concentration in the gas was increased and vapor phase combustion was caused downstream of the catalyst body, and the temperature of the combustion gas could be increased. As a result, high temperature deterioration of the catalyst body was eliminated and low NOx complete combustion was achieved.

However, the vapor phase combustion downstream of the catalyst body in the above proposal has the following problems. That is, the fuel concentration distribution is non-uniform, which is caused by adding a high concentration of unmixed air from the fuel nozzle 1'to the flow of the combustion gas discharged from the catalyst body 7.

That is, in the downstream of the catalyst body, there are a part where the fuel concentration is high and a part where the fuel concentration is low. As a result, the combustion temperature inevitably becomes high in a portion where the fuel concentration is partially high, which causes NOx generation.

In order to solve such a problem, it has been attempted to provide a large number of fuel nozzles downstream of the catalyst to make the fuel concentration uniform, but such a method is difficult to control the fuel flow rate of each noise. However, the above problems have not been solved yet.

[Object of the Invention] The present invention solves the above-mentioned problems, keeps the thermal load on the catalyst body constant, and makes the fuel concentration distribution downstream of the catalyst body uniform, and the flow rate of the mixed gas and An object of the present invention is to provide a gas turbine combustor that can respond to changes in fuel concentration and can control the generation of NOx.

[Summary of the Invention] As a result of intensive studies to achieve the above object, the present inventors have installed a gas supply means including an oxidizing gas in addition to a fuel supply means downstream of the catalyst body, and The present invention has been completed by finding the fact that the above object can be achieved by using a combustor structure as described later so that the supply gas from the supply means and the combustion gas from the catalyst body are uniformly mixed. It was

That is, the gas turbine combustor of the present invention is provided with a mixed gas supply part composed of a gas containing an oxidizing gas and a fuel, a catalyst body installed downstream of the mixed gas supply part, and a downstream side of the catalyst body. A gas turbine combustor comprising a main passage through which an outflow gas from a catalyst body passes and at least one gas dividing passage, wherein at least one of the gas dividing passages includes the gas dividing passage and the main passage. And a catalyst combustion gas discharge port having a nozzle structure for connecting to and a fuel supply means separate from the mixed gas.

First, the structure of the mixed gas supply unit composed of the gas containing the oxidizing gas and the fuel in the present invention is not particularly limited, and the supplied fuel and the oxidizing gas such as air are mixed. Any configuration may be used as long as it is provided.

For example, an example of the gas turbine combustor of the present invention is shown in FIG. 1. In FIG. 1, 1, 1'is a fuel nozzle, 2 is a spark plug, 3 is combustion air, and 8 is a swirler.

In the mixed gas supply unit, the fuel supplied from the fuel nozzle 1 is sufficiently mixed with the combustion air 3 by the swirler 8 to form a mixed gas. Then, the mixed gas is ignited by the spark plug 2 and heated to a certain degree. This is done in order to raise the temperature of the mixed gas to the working temperature of the catalyst body so as to promote the catalytic reaction smoothly, and is not necessarily required depending on the type of fuel used and the type of catalyst.

The catalyst body 7 is installed downstream of the mixed gas supply unit. The performance of the catalyst body 7 and the catalyst metal are not particularly limited, but the amount of the catalyst body 7 to be installed may be determined according to the pressure loss required for the catalyst body, the activity of the catalyst body, the type of fuel, and the like. In particular, it is desirable to determine the installation amount of the catalyst body corresponding to the case where the load connected to the combustor is low.

It is desirable that the flow rate of the mixed gas, that is, the fuel and the air supplied to the catalyst body from the mixed gas supply section be constant in order to reduce the thermal load on the catalyst body.

Further, in the present invention, at least one gas dividing channel is provided downstream of the catalyst body. This is a flow path that divides the combustion gas discharged from the catalyst body into at least two.

As a flow path having such a structure, for example, as shown in FIG. 1, the flow is divided by arranging a cylindrical member 10 inside a cylindrical outer shell 9 supporting a catalyst body 7. Examples of the channel 11 and the channel 12 are given, but the channel of the present invention is not limited thereto. The inner cylindrical member 10 may be installed in contact with the catalyst body 7 or may be installed separately. The split ratio of the combustion gas may be set according to the usage conditions of the combustor.

At least one of the gas dividing flow paths is provided with a catalytic combustion gas exhaust port having a nozzle structure. That is, the structure is such that the combustion gas that has flowed into the divided flow path is discharged only from the nozzle.

Further, this channel is provided with a fuel supply means capable of adjusting the supply amount and a gas supply means containing an oxidizing gas as necessary.

Such a flow path is formed by the cylindrical member 10 as shown in FIG.
May be formed on the outer side of. Conversely, it may be formed inside. Further, the diameter of the nozzle 13 and the number of nozzles 13 to be installed are appropriately determined according to the flow rate, the fuel concentration, and the like. Further, the position of the nozzle 13 is not particularly limited, but it is preferably set downstream of the fuel supply means 14 and the supply means 15 of a gas containing an oxidizing gas, and more preferably downstream of the flow path 11. It is preferable to set it near the end, and it is also preferable to set so that the gas jetted from the nozzle 13 is jetted into the remaining channel 12.

In the combustor of the present invention, the combustion gas discharged from the catalyst body 7 is split into the flow passage 11 and the flow passage 12.

And when it is not necessary to handle high loads,
Combustion gas flowing into 11 is fuel supply means with control valve 14 '
By being uniformly mixed with the fuel adjusted to a predetermined flow rate supplied from 14, the generation of a high fuel concentration location and a low fuel concentration location is suppressed and ejected from the nozzle 13.

Then, the gas ejected from the nozzle 13 is mixed with the combustion gas flowing in the flow path 12 and the gas phase combustion is performed in a state where the fuel concentration distribution becomes uniform.

At this time, if the structure of the combustor downstream of the nozzle 13 has a structure for delaying or backflowing the gas, for example, a structure 16 for expanding the gas flow as shown in FIG. Combustion is performed stably. Further, if an ignition source such as the igniter 17 is provided, it is possible to easily start the vapor phase combustion.

Then, the combustion gas after the vapor-phase combustion has a predetermined temperature by the dilution gas from the gas supply means 18 containing the oxidizing gas with the control valve 18 'installed downstream of the vapor-phase combustion region near the nozzle 13. And is supplied to the gas turbine nozzle 6.

On the other hand, when it is necessary to handle a high load, the flow path 11
In the above, by supplying a large amount of fuel from the fuel supply means 14 and supplying a diluting gas from the gas supply means 15 containing an oxidizing gas, the fuel concentration distribution is kept uniform and the fuel concentration is lowered, Due to the fuel supply of
Suppresses sudden generation of NOx.

As described above, the gas turbine combustor of the present invention can cope with load fluctuations and can make the fuel concentration distribution uniform.

[Examples of the Invention] Example 1 A simulated combustor having a structure as shown in FIG. 2 was produced. The catalyst body 20 is a honeycomb catalyst body (Pt type) with a diameter of 100 mm and a length of 90 mm.
It was used. The diversion channel has a double ring structure (diameter of the inner ring is 80 m
m, diameter of outer ring 100 mm). The outer flow path 21 formed of the double ring structure has a nozzle structure. That is,
Twelve holes 22 having a diameter of 3.5 mm were formed on the wall surface of the inner ring from the lower tip of the double ring structure to a position 80 mm downstream from the tip.

Then, combustion air 23 preheated to 450 ° C. was supplied at 4 Nm ³ / min, and natural gas was supplied from the fuel supply device 24 at a flow rate of 80 / min. Further, 90 / min of fuel was supplied from the fuel supply device 25, and air was not supplied from the air supply device 26.

As a result, the maximum temperature of the catalyst body was about 800 ° C, which was below the heat resistant temperature of the catalyst body. Further, gas-phase combustion was stably carried out in the downstream region of the catalyst body, and the amount of NOx produced and the combustion rate were as shown in the table.

Example 2 Using the combustor of Example 1, combustion was performed under the same conditions as in Example 1 except that the fuel supply rate from the fuel supply device 25 was 150 / min in order to increase the temperature of the combustion gas. It was

Comparative Example Example 2 using a combustor having a structure as shown in FIG.
Combustion was performed with the same fuel supply amount as. As a result, NOx
As the amount of fuel supplied from the fuel supply device 25 was increased, the amount of NOx increased, and NOx increased to about twice as much as that in Example 2 in the combustion temperature range of 1500 to 1600 ° C.

Example 3 Using the combustor of Example 1, the fuel supply amount from the fuel supply device 25 was set to 165 / min and the air supply was performed in order to increase the temperature of the combustion gas and suppress the rapid generation of NOx. The amount of air supplied from the device 26 was 0.6 Nm ³ / min. As a result, the amount of NOx generated was lower than in Example 2.

 The above results are collectively shown in the table.

[Effects of the Invention] As described above, the gas turbine combustor of the present invention is
The thermal load on the catalyst body can be kept constant, the fuel concentration distribution on the downstream side of the catalyst body can be made uniform, and it can respond to changes in the mixed gas flow rate and fuel concentration.
It is possible to suppress the generation of NOx even in the high temperature range, and its industrial value is great.

[Brief description of drawings]

1 and 2 are schematic views showing an example of a gas turbine combustor of the present invention, and FIGS. 3 to 5 are schematic views showing an example of a gas turbine combustor having a conventional structure. is there. 1,1 ', 14,25: Fuel nozzle (fuel supply means) 2: Spark plug 3,23: Combustion air 6: Turbine nozzle 7,20: Catalyst 8: Swirler 15,18,26: Oxidizing gas Including gas supply means

Front page continuation (72) Inventor Kenjiro Izumigawa 2-4-1 Nishitsutsujioka, Chofu-shi, Tokyo Inside the Research Institute of Tokyo Electric Power Company (72) Terunobu Hayata 1 Komukai Toshiba-cho, Kawasaki-shi, Kanagawa Prefecture Incorporated company Toshiba Research Institute (72) Inventor Tomiaki Furuya No. 1 Komukai Toshiba-cho, Kouki-ku, Kawasaki-shi, Kanagawa Incorporated Toshiba Research Institute (72) Inventor Ya Yamanaka Komukai Toshiba, Kawasaki-shi, Kanagawa Town No. 1 Incorporated Toshiba Corporation Research Institute (72) Inventor Junji Kozuka Komukai-shi, Kawasaki City Kanagawa Prefecture Komukai Toshiba No. 1 Incorporated Toshiba Corporation Research Institute (56) Reference JP-A-60-122807 (JP , A) JP 60-186622 (JP, A) JP 59-129330 (JP, A) JP 60-205127 (JP, A) JP 62-218730 (JP, A) JP 58-47610 (JP, B2)

Claims (4)

[Claims] 1. A supply portion of a mixed gas composed of a gas containing an oxidizing gas and a fuel, a catalyst body installed downstream of the supply portion of the mixed gas, and an outflow gas from the catalyst body downstream of the catalyst body. A gas turbine combustor comprising a main flow passage through which a gas passes and at least one gas split flow passage, wherein at least one of the gas split flow passages has a nozzle structure connecting the gas split flow passage and the main flow passage. A gas turbine combustor characterized in that a catalytic combustion gas exhaust port is provided and a fuel supply means separate from the mixed gas is provided. 2. The gas turbine combustor according to claim 1, further comprising a gas ignition source provided downstream of the gas division flow path. 3. The method according to claim 1, wherein a downstream region of the gas dividing flow passage has a structure for delaying or backflowing the gas flow.
A gas turbine combustor according to the paragraph. 4. A gas turbine combustor according to claim 1, wherein said gas dividing flow passage is provided with a gas supply means containing an oxidizing gas.