JPH0833199B2 - 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 performed using a spark plug or the like to perform homogeneous combustion. An example of such a combustor is shown in FIG. In the combustor of FIG. 4, the fuel injected from the fuel nozzle 1 is mixed with the combustion air 3 and ignited by the spark 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 NO _x is generated 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 such problems of the gas turbine combustor, various combustion methods have been studied, and recently, a catalytic combustion method using a solid phase catalyst has been proposed.

In this catalytic combustion system, a lean fuel that is not burned in a normal combustor can be burned by using a catalyst, so that the burning temperature does not become high enough to generate NO _x .
Further, the turbine inlet temperature can be made the same as the conventional one. FIG. 5 is a conceptual diagram of an example of a combustor used in the catalytic combustion system. The numbers in the figure are the 4th
Represents the same element as the figure. 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,
Here, a mixed gas of fuel and air is combusted. Such a gas turbine combustor also has the following drawbacks. In other words, the temperature of the combustion gas to be injected into the turbine, which is required in the gas turbine, is approximately 1100 ° C. Therefore, when the mixed gas is burned up to that temperature by the catalytic body, the catalytic body itself becomes 1100 ° C.
There is a problem that the catalyst body is damaged by being heated to a temperature higher than ℃.

In the experiments conducted by the present inventors, the temperature of the catalyst body was 1100-
It has been confirmed that when the temperature is raised to 1300 ° C, a part of the catalyst body is eluted and the catalyst body is damaged. Despite such circumstances, there is currently no catalyst body having excellent resistance to high temperatures of 1100-1300 ° C.

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. 6, this method is a method in which a mixed gas of fuel and air is first burned by the catalytic body 7. Normally, when a flame-retardant fuel is used in the catalyst body, combustion by a catalytic reaction and gas-phase combustion occur simultaneously. However, in the above proposal, the fuel concentration, temperature, The flow rate is controlled. Therefore, since the catalyst does not involve gas phase combustion, it does not reach a high temperature, only part of the fuel burns, and combustion gas containing unburned fuel is discharged from the catalyst.

In the above proposal, the fuel 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 NO _x complete combustion was achieved. It should be noted that if the ratio of the total amount of fuel supplied to the total amount of air supplied is increased, the amount of NO _x generated will also increase, but the combustion gas supplied to the gas turbine can be heated to the same extent.

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 place where the fuel concentration is partially high, which causes the generation of NO _x .

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] An object of the present invention is to provide a gas turbine combustor that solves the above-mentioned problems, makes the fuel concentration distribution downstream of the catalyst body uniform, and suppresses the generation of NO _x .

[Summary of the Invention] As a result of intensive studies to achieve the above object, the present inventors further added a fuel to a part of a low-fuel-concentration mixed gas consisting of fuel and air initially supplied. To produce a mixed gas with a high fuel concentration, while supplying a part of the above-mentioned low-fuel-concentrated mixed gas to the catalytic body, where only combustion by catalytic reaction occurs, and then discharged from the catalytic body. The idea was that if the burned combustion gas and the mixed gas with a high fuel concentration were mixed, there would be no part with a high fuel concentration, and therefore gas phase combustion could be performed with low NO _x . .

As a result of various studies on the structure of a gas turbine combustor capable of realizing the above concept, the inventors have found that a gas turbine combustor having a structure as described below can realize the above concept, and completed the present invention.

That is, the gas turbine combustor of the present invention is provided with a mixed gas supply part composed of an oxidizing gas and a fuel, and at least two independent parts provided downstream of the mixed gas supply part.
One flow path and a gas-phase combustion section provided downstream of the terminal end of the flow path, and a catalyst body is installed in at least one of the flow paths, and at least another of the flow paths is provided. One is characterized in that a means for supplying the fuel is installed.

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

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.

Further, the mixed gas supplied to the flow passage described later may be a mixed gas to which fuel is further added from the fuel nozzle 1 '.

Further, in the present invention, a part of the mixed gas is guided to the catalyst body and the other part is guided to the flow path where the catalyst body does not exist. That is, in the downstream region of the mixed gas generating portion of the combustor, the mixed gas flow path is divided into at least two parts, and these are independent of each other.

As a flow path having such a structure, for example, as shown in FIG. 1, a cylindrical catalyst body holding member is provided inside a cylindrical outer shell 13.
Examples thereof include, but are not limited to, a flow channel having a configuration in which 14 is provided, a flow channel having a configuration in which one partition plate that partitions the space in the flow direction is attached inside the outer shell 13.

In the combustor of the present invention, in the flow path having the above-mentioned configuration, the catalyst body is installed in one flow path, and the fuel supply means is installed in the other flow path without the catalyst body installed. There is. For example, in FIG. 1, a fuel supply nozzle 1 ″ is provided in the outer flow passage 9, and a catalyst body 7 is installed in the inner flow passage 10.

The position where the fuel nozzle 1 ″ is installed is not particularly limited as long as it is within the flow passage 9, but its position in the flow passage direction is not limited.
In order to effectively mix the mixed gas and the fuel supplied from the fuel nozzle 1 ″, it is preferable to install the mixed gas on the upstream side of the flow passage 9 of the fuel nozzle 1 ″. In addition to the fuel supply means, the flow path 9 may be provided with a supply means such as water vapor.

With the above configuration, a part of the mixed gas is supplied to the catalyst body 7. Since the fuel concentration in the supplied mixed gas is not so high, the catalytic body 7 only performs combustion by catalytic reaction and does not perform gas phase combustion. Therefore, the combustion gas discharged from the catalyst body contains unburned fuel. Therefore, in the catalyst body, since the temperature of the catalyst body itself does not become so high, its deterioration or damage does not occur.

Further, when the structure of the flow path is configured as shown in FIG. 1, the temperature of the mixed gas flowing through the flow path is lower than that of the combustion gas in the catalyst body, so that the catalyst body holding member 14 can be cooled. It is useful.

On the other hand, the other part of the mixed gas is supplied to the flow path in which the catalyst body is not installed. The fuel is added from the fuel supply means to the mixed gas supplied to this flow path, so that the fuel concentration in the mixed gas becomes high, and the mixed gas and the fuel added in this flow path are sufficient. Mixed.

The amount of fuel supplied from the fuel nozzle 1 ″ provided in the flow path 9 needs to be adjusted so that the gas phase combustion temperature falls within a temperature range in which NO _X is not generated.

Further, the supply amount of the mixed gas to each flow path can be determined by the catalyst capacity and the specifications of the combustor.

And finally, the mixed gas discharged from the flow path 9 and the combustion gas discharged from the catalyst body 7 are at the rear of the flow path,
That is, they are mixed downstream of the catalyst body. In the mixing in the rear of the flow path, the fuel is not directly added to the combustion gas as in the conventional case, but the mixed gas having a high fuel concentration and the combustion gas sufficiently mixed by the above-described configuration are mixed.
In the gas obtained as a result of the mixing, there is no part where the fuel concentration is high. Therefore, a gas having a uniform concentration distribution and a high fuel concentration is generated behind the flow path.
Therefore, in this region, gas phase combustion is performed with almost no generation of NO _X , and the fuel is completely burned.

If, for example, as shown in FIG. 2, a portion 11 that delays or reverses the flow of gas is formed in the outer shell on the downstream side of the catalyst body, the gas flow circulates behind this portion 11 and a flame is formed to form a gas phase. Combustion is performed stably.

In the area downstream of the catalyst body, as shown in FIG. 3, for example,
If an ignition source such as the igniter 12 is provided, it is possible to start the gas phase combustion easily, which is effective.

[Examples of the Invention] Examples 1 to 4 A simulated combustor having a structure as shown in Fig. 2 was produced. The flow passage cross-sectional area ratio between the flow passage in which the catalyst body of this combustor is installed and the flow passage in which it is not installed is 8: 2, and a precious metal-based honeycomb catalyst body having a diameter of 100 mm and a length of 90 mm is used as the catalyst body. Using.

Natural gas (F ₁ ) and air (A) have a volume ratio (F ₁
/ A) mixed gas was heated up to 450 ℃ in an electric furnace and converted into 500 ℃ at a flow rate of 30 m / sec to the catalyst and flow path of the combustor for combustion.

It should be noted that the ratio of the mixed gas composed of natural gas (F ₁ + F ₂ ) containing natural gas (F ₂ ) supplied from the fuel nozzle 1 ″ provided on the flow path 9 and air (A). Was set as shown in the table, and ignition of gas phase combustion was performed by an igniter.

Then, the NO _x generation amount (ppm) in the exhaust gas generated by combustion was measured at a position 700 mm downstream of the catalyst body. The combustion efficiency was 99% or more in all cases.

As a comparative example, a simulated combustor having the structure shown in FIG. 6 was used to perform combustion under the same conditions as in the example. In addition,
Four fuel nozzles 1'provided downstream of the catalyst body 7 are installed,
The amount of fuel supplied from this nozzle is F _2. Was calculated.

 The above results are shown in the table.

[Effects of the Invention] As is apparent from the embodiments of the invention, the gas turbine combustor of the present invention makes the fuel concentration distribution downstream of the catalyst body uniform without increasing the thermal load on the catalyst body. The amount of NO _X generated can be suppressed. Moreover, its industrial value and can get hot combustion gases without increasing of the NO _X generation amount also increases the presence rate of the fuel in the mixed gas is larger.

[Brief description of drawings]

1 to 3 are schematic views showing an example of a gas turbine combustor of the present invention, and FIGS. 4 to 6 are schematic views showing an example of a gas turbine combustor having a conventional structure. is there. 1,1 ′, 1 ″: Fuel nozzle, 2: Spark plug 3: Combustion air, 6: Turbine nozzle 7: Catalyst body, 8: Swirler 11: Gas flow delay or backflow part 12: Igniter

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 60-147034 (JP, A) JP 60-186622 (JP, A) JP 59-129330 (JP, A) JP 60-205127 (JP, A) JP 62-218727 (JP, A) JP-A-62-218731 (JP, A) JP-B-58-47610 (JP, B2)

Claims (3)

[Claims] 1. A mixed gas supply part comprising an oxidizing gas and a fuel, at least two flow paths provided independently of each other downstream of the mixed gas supply part, and an end part of the flow path. A gas-phase combustion section provided downstream, and a catalyst body is installed in at least one of the flow paths, and a fuel supply means is installed in at least another of the flow paths. A gas turbine combustor characterized in that 2. The gas turbine combustor according to claim 1, wherein the gas phase combustion section has a structure having a portion for delaying or backflowing the gas flow. 3. The gas turbine combustor according to claim 1, wherein a gas ignition source is provided in the gas phase combustion section.