JPH05215338A - Gas turbine combustion device and its combustion method - Google Patents

Abstract

PURPOSE:To reduce NOx and improve a flame holding performance in a gas turbine device in which gas fuel and liquid fuel are applied. CONSTITUTION:A pilot nozzle 11 is arranged on a central line of an inner cylinder 14. Around this pilot nozzle main nozzles 12 and 13 of the first and second groups comprised of a plurality of nozzles are arranged on each of pitch circles having different diameters (d) and (D) at its circumferential edge. Fuel is mixed with air at each of the main nozzles 12 and 13 of the groups so as to perform a pre-mixing and combustion, a dispersion and combustion is carried out at the pilot nozzle 11 and then the nozzle acts as a flame holder for the pre-mixing flame. In addition, the group of the main nozzles to be used is properly selected in response to the load, thereby the reduction of NOx can be realized over a range from a partial load to a full load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dual fuel gas turbine combustor using a gas fuel and a liquid fuel and a combustion method thereof.

[0002]

2. Description of the Related Art For example, as a combustor which uses a gas fuel such as natural gas and a liquid fuel such as kerosene or light oil and burns them independently or mixes them at an arbitrary ratio and burns them, Fuel-fired gas turbine combustors are known. FIG. 3 is a vertical cross-sectional view showing a nozzle portion of a conventional dual-fuel gas turbine combustor.

In FIG. 3, a plurality of inner cylinders 1 of a dual fuel gas turbine combustor are arranged in a combustor casing 2 in the circumferential direction. A liquid fuel nozzle 3 is arranged on the center line of the inner cylinder 1, and a spray air nozzle 4, a water injection nozzle 5 and a gas fuel nozzle 6 are concentrically arranged so as to surround the liquid fuel nozzle 3. Further, a swirler 7 that creates a swirling air flow for flame holding and combustion promotion is provided on the outer peripheral portion of the gas fuel nozzle 6.

In the gas turbine combustor described above,
Liquid fuel is injected from the liquid fuel nozzle 3. Further, the gas fuel and the injected water are respectively injected from the holes A and B formed in the gas fuel nozzle 6 and the water injection nozzle 5 at equal pitches in the circumferential direction. Further, the spray air is ejected from the annular passage C of the spray air nozzle 4. And the jet water jetted from the water jet nozzle 5 is
It plays the role of reducing NOx by lowering the combustion temperature and flame temperature. Further, the atomizing air ejected from the atomizing air nozzle 4 promotes atomization of the liquid fuel ejected from the liquid fuel nozzle 3 to promote combustion.

[0005]

By the way, in the conventional gas turbine combustor having the above-mentioned structure, in order to reduce NOx, water or steam is injected to lower the combustion temperature or flame temperature. However, if the temperature of the flame is lowered, it becomes difficult to hold the flame, and a fire may be lost depending on the operating conditions.
There was a problem of stopping the gas turbine.
In addition, the injection of water or steam was also supposed to reduce the efficiency of the gas turbine.

The present invention solves the problems of the prior art and provides a gas turbine combustor and a combustion method thereof which can meet NOx emission regulations which are becoming more and more strict in order to prevent environmental pollution. The purpose is to provide.

[0007]

In order to achieve the above object, the present invention relates to a gas turbine combustor using a gas fuel and a liquid fuel, and a pilot nozzle arranged on the center line of the inner cylinder, A plurality of main nozzle groups, each having a plurality of nozzles arranged on pitch circles having different diameters around the pilot nozzle, are provided.

[0008]

[Operation] According to the above means, the fuel is mixed with air in the main nozzle group to perform premixed combustion, and the pilot nozzle performs diffusion combustion to act as a flame stabilizer for the premixed flame. Also, since multiple groups of main nozzles are provided on pitch circles of different diameters, NOx reduction is achieved from partial load to full load range by selecting the main nozzle group to be used according to the load. can do.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS. FIG. 1 is a front view showing a nozzle portion of a gas turbine combustor according to this embodiment, and FIG. 2 is a sectional view taken along line II-II of FIG.

As shown in FIG. 1, the gas turbine combustor according to the present embodiment has one pilot nozzle 11 and equal intervals on a pitch circle having a diameter d centered on the pilot nozzle 11, for example. The first group of main nozzles 12 is a set of four, and, for example, four are arranged at equal intervals on a pitch circle having a diameter D (where D> d) centered on the pilot nozzle 11 is a set. Main nozzle 1 of the second group
3 is provided at the head of an inner cylinder 14 provided in a combustor casing (not shown) and shares a combustion region.

The pilot nozzle 11 is arranged on the center line of the inner cylinder 14 and is used for flame holding. As shown in detail in FIG. 2, a liquid fuel nozzle 15 for injecting liquid fuel is provided in the center. An atomizing air nozzle 16 provided around the nozzle for ejecting atomizing air, and a gas fuel injection hole 17
A premixed pilot gas nozzle 17 with A is provided. A swirler 18 is provided outside the premixed pilot gas nozzle 17 for expanding the circulating flow of the combustion air to ensure flame holding.

On the other hand, the main nozzles 12 of the first group are located on the upstream side, a liquid fuel nozzle 19 for injecting liquid fuel is provided in the center, and a gas fuel injection hole 2 is provided around the liquid fuel nozzle 19.
A premix main gas nozzle 20 having 0A is provided. Further, the main nozzles 13 of the second group are located downstream of the tip of the main nozzles 12 of the first group by a distance l in the axial direction. A liquid fuel nozzle 21 for injecting liquid fuel is provided in the center, and a premix main gas nozzle 22 having a gas fuel injection hole 22A is provided around the liquid fuel nozzle 21. The main nozzles 1 of the first and second groups
A swirler is not provided outside of Nos. 2 and 13, but this is to suppress mixing with an adjacent burner and prevent generation of CO during partial load.

Next, the operation will be described. First, the pilot nozzle 11 is ignited and used as a spark. The fuel from the pilot nozzle 11 performs diffusion combustion and acts as a flame stabilizer for the premixed flame. Then, during the period from the start up to almost 1/2 load, only the main nozzles 12 of the first group arranged immediately outside the pilot nozzles 11 are used, and the main nozzles 13 of the second group are used. Do not supply liquid or gas fuel. However, at this time, only air is ejected from the main nozzles 13 of the second group. From the 1/2 load to the full load, in addition to the main nozzles 12 of the first group, the main nozzles 1 of the second group 1
Also try to use 3. In this case, the main nozzles 12 of the first group serve as the ignition source of the main nozzles 13 of the second group.

That is, the main nozzles 12, 13 of each group
In, the fuel is mixed with air for premixed combustion,
Since the main nozzle group to be used can be adjusted according to the load, the premixed gas will not be diluted. Further, since the main nozzles 12 and 13 of each group have different axial positions and diameters of pitch circles, even if there is a main nozzle group that is not used, the premixing flames of the main nozzle group that are in use are adjacent to each other. It is not cooled by the air flow of the unused main nozzle group and there is no risk of misfire.

In the main nozzles 12 and 13 of each group, the liquid fuel injected from the liquid fuel nozzles 19 and 21 is atomized by the gas fuel injected from the premix main gas nozzles 20 and 22, and the gas fuel is When not in use, air atomizes the liquid fuel. Further, atomization of the liquid fuel in the pilot nozzle 11 is performed by the atomizing air injected from the atomizing air nozzle 16.

[0016]

As described above, according to the present invention, the liquid fuel of the main nozzle can be atomized by the gas fuel injected from the premixed main gas nozzle without requiring special atomizing air. .. Also, this liquid fuel is premixed with air in the same space as the combustion area, so that flashback is prevented. Further, since no water or steam is injected into the combustor, misfire is prevented. The main nozzles are divided into a plurality of groups having different pitch circle diameters and arranged, and the main nozzle group to be used is adjusted according to the load.
There is provided a gas turbine combustor and a combustion method thereof, which can significantly reduce x, and can also prevent misfire that is a concern when NOx is reduced.

[Brief description of drawings]

FIG. 1 is a front view showing a nozzle portion of a gas turbine combustor according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a vertical sectional view showing a nozzle portion of a conventional gas turbine combustor.

[Explanation of symbols]

 11 Pilot Nozzle 12 Main Nozzle of First Group 13 Main Nozzle of Second Group 14 Inner Cylinder

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Katsunori Tanaka 1-1-1, Niihama, Arai-cho, Takasago-shi, Hyogo Mitsubishi Heavy Industries, Ltd. Takasago Plant (72) Inventor Watao Sato 2-chome, Niihama, Arai-cho, Takasago-shi, Hyogo No. 1 Mitsubishi Heavy Industries, Ltd. Takasago Research Center

Claims (2)

[Claims] 1. In a gas turbine combustor using a gas fuel and a liquid fuel, a pilot nozzle arranged on a center line of an inner cylinder and a pitch circle having different diameters around the pilot nozzle as a center. A gas turbine combustor comprising: a plurality of main nozzle groups each having a plurality of nozzles. 2. The gas turbine combustor according to claim 1, wherein among the main nozzle groups located on pitch circles having different diameters with the pilot nozzle as the center, the main nozzle group on the side closer to the pilot nozzle depending on the load. A combustion method for a gas turbine combustor, characterized in that combustion is performed sequentially from a main nozzle group.