JP3110300B2 - Combustor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a blast furnace gas (Bla
In a st Furnace Gas ... BFG-fired combustor, natural gas (Liquified) is used.
Natural Gas (hereinafter referred to as LNG) relates to a combustor capable of burning.

[0002]

2. Description of the Related Art In order to increase the efficiency of a gas turbine combined cycle, it is necessary to increase the turbine inlet temperature. However, an increase in the inlet temperature causes an increase in NOx, destruction of the ozone layer, generation of photochemical smog, etc. Cause environmental problems.

When the generation of NOx is viewed from the fuel side, NOx
x is generated from a nitrogen compound contained in the fuel, and in a power plant using a special fuel such as BFG or coal gasification gas (coke oven gas COG) as a fuel,
Although this is a problem as fuel NOx, LNG, which is the main fuel, does not contain this and does not cause any particular problem.

[0004] On the other hand, LNG is a high calorie fuel, and when the flame temperature is high, a high concentration of thermal NOx is generated. At present, this BFG-fired combustor uses a BFG
It is a dedicated burner.

FIG. 2 is a schematic view of a conventional BFG-fired combustor. An annular BFG nozzle 21 and a primary combustion air nozzle 22 surrounding it are arranged.

[0006]

The above-mentioned conventional BFG
A combustor using a low-calorie, poorly combustible fuel, such as a burn combustor, is significantly different from a normal combustor (for example, an LNG combustor) in the method and distribution of air for combustion.

[0007] For this reason, it is difficult to make a dual fuel with a normal fuel such as LNG, and it is a reality that it has not been put to practical use.

It is an object of the present invention to solve this problem and to provide a dual combustor.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has first to fourth flow paths for supplying a combustion fluid to a nozzle, and uses a blast furnace gas (BFG) for the fuel. ) And natural gas (LNG). In the case of blast furnace gas (BFG) firing, the first to fourth flow paths are blast furnace gas (BFG), pause,
The blast furnace gas (BFG) and the flow path of the combustion air, and the first to fourth flow paths in the case of natural gas (LNG) firing,
Natural gas (LNG), natural gas (LNG), combustion air,
The present invention provides a combustor that switches to the combustion air flow path and premixes the natural gas (LNG) in the second flow path with the combustion air in the third and fourth flow paths. The natural gas (LNG) is used by switching the flow path between natural gas (LNG) burning and natural gas (LNG) burning. In particular, when natural gas (LNG) is burned, natural gas (LNG) as a main fuel is added to combustion air flowing through a double air nozzle. ) Is premixed and becomes lean fuel, and preferable combustion is performed.

In addition, when blast furnace gas (BFG) is fired, the blast furnace gas (BFG), which is the fuel, is not too concentrated toward the center and the air around the main fuel does not become too much, and the center becomes a pilot nozzle. The flame is held by the diffusion flame formed by the blast furnace gas (BFG) supplied by the flow path, and stable combustion can be ensured.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG.

Reference numeral 1 denotes a combustor, the nozzle portion of which is constituted by collecting a plurality of flow paths, a first flow path 2 at a central portion, a second flow path 4 outside thereof, and a nozzle outside thereof. Third flow path 5,
Further, a fourth flow path 6 is disposed outside the fourth flow path.

The second flow path 4 communicates with the third flow path 5 through a communication hole 7 and passes through a plurality of branch paths 8 extending radially from the second flow path 4 through a communication hole 9. 4 communicates with the flow path 6.

When the combustor 1 is used as a BFG combustor, a BFG is provided in the first passage 2 at the center.
Is supplied to form a diffusion flame zone 3 in the combustor as a pilot nozzle 2A to hold the flame and stabilize combustion even if the main fuel is fuel-lean.

Further, the second flow path 4 is stopped, and nothing flows here. Then, BFG is supplied to the third flow path 5 and is combusted together with the combustion air supplied to the fourth flow path 6.

On the other hand, when the combustor 1 is used as an LNG combustor, the LNG combustor 1
Is diffused and combusted by the pilot nozzle 2 in the same manner as in the case of the BFG combustor, and a diffusion flame zone 3 is formed in the combustor for flame holding.

Around the pilot nozzle 2, LNG is supplied through a second flow path 4 and serves as a main nozzle.
Further, combustion air is supplied to the third flow path 5 and the fourth flow path 6, and LNG supplied to the second flow path 4 is supplied from the communication hole 7 or the communication hole 9 of the branch passage 8. Upon receiving, a pre-mixed gas is formed and is ejected from the nozzles 5A and 5B, and is burned by the flame of the diffusion flame region 3 and held.

The switching of the flow path in the case of changing from the BFG firing to the LNG firing is performed by a switching device (not shown).

The first to fourth flow paths 2, 4, 5, 6
The respective fluids to be supplied to the tank are classified and arranged into patterns when the fuel used is BFG and when the fuel used is LNG, as shown in the table below.

[0020]

[Table 1]

As described above, according to the present embodiment, by switching the flow path according to the case where the fuel used is BFG or LNG, one fuel cell can cope with both fuels, and the so-called dual fuel system can be realized. It is now possible.

In the case of LNG firing, low NOx combustion by the premixing method is achieved, and in the case of BFG firing, the fuel is not deviated too much toward the center and is maintained by a diffusion flame that becomes a pilot flame. It is flamed and ensures stable combustion.

Although the present invention has been described with reference to the illustrated embodiments, the present invention is not limited to such embodiments.
It goes without saying that various changes may be made to the specific structure within the scope of the present invention.

[0024]

As described above, according to the present invention, even if the fuels used are BFG and LNG which have greatly different fuel properties, they can be burned in the same combustor, and have low NOx.
And it became possible to fire safely and reliably.

Therefore, even if the combustor normally burns BFG, even if the blast furnace is stopped and the BFG is shut down, it can be switched to LNG immediately and operated, so that the turbine can be continuously operated. Driving has become possible, and operation stability and reliability have been further improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a combustor according to an embodiment of the present invention.

FIG. 2 is a schematic view of a conventional combustor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Combustor 2 1st flow path 4 2nd flow path 5 3rd flow path 6 4th flow path

Continuation of the front page (56) References JP-A-9-189407 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23C 1/00 F23D 17/00 F23R 3/36 F02C 7 /twenty two

Claims (1)

(57) [Claims] 1. A fuel supply system comprising a first to a fourth flow path for supplying a combustion fluid to a nozzle, wherein fuel is switched between blast furnace gas and natural gas. The first to fourth flow paths are blast furnace gas, pause, blast furnace gas, and combustion air flow paths. In the case of natural gas firing, the first to fourth flow paths are natural gas, natural gas, A combustor characterized by switching to combustion air and a flow path of combustion air and premixing the natural gas in the second flow path with the combustion air in the third and fourth flow paths.