JPH09119638A - Gas turbine combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a reduction in temperature totally while eliminating instability of a flame by distributing steam for lowering NOx evenly within a combustion area in a gas turbine combustor. SOLUTION: In this combustor, a fuel oil is jetted to a combustion area within an inner cylinder 2 wrapped with an outer cylinder 1 from a fuel nozzle 5 and steam thereto from a hole X on the front of a nozzle holder separately while combustion air is supplied through a scoop 3 and internal and external clearances of a baffle 6 of the inner cylinder. In this case, a steam path 7 is made to communicate with the side of a nozzle holder 4 and a bypass hole Y for jetting steam is provided to mix the combustion air flowing in from the internal and external clearances of the baffle 6 and the scoop 3 with steam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to nitrogen oxides (NO
x) A gas turbine combustor in which steam for reduction is injected into a combustion region.

[0002]

2. Description of the Related Art Nitrogen oxides (NOx) such as nitric oxide (NO) and nitrogen dioxide (NO ₂ ) generated when burning heavy oil, kerosene, etc., combine with hydrocarbons to form oxidants, and photochemical smock Cause.

Therefore, in a gas turbine combustor using a diffusion type nozzle, at present, as a measure to reduce this NOx, steam is injected from a few holes on the front surface of the nozzle holder into the combustion region of the combustor, and the flame of this portion is burned. NOx to lower the temperature
The occurrence of is suppressed.

This currently used gas turbine combustor is shown in FIG. In the combustion region in the cylindrical inner cylinder 2 surrounded by the cylindrical outer cylinder 1, the combustion nozzle 5 held in the central portion of the cylindrical nozzle holder 4 to the nozzle holder 4
Fuel oil is injected through the hole 4a on the front surface of the. Further, several holes X are formed in a portion of the front surface of the nozzle holder 4 which is radially outward of the combustion nozzle 5. Each hole X is provided at the tip of a plurality of steam passages 7 provided in the insert holder 4, and the water vapor from the steam passages 7 is provided in the same hole X.
Is injected into the combustion region in the inner cylinder 2.

Further, a flow between the outer cylinder 1 and the inner cylinder 2 flows from the inner and outer gaps of the baffle 6 provided between the nozzle holder 4 and the inner cylinder 2 and the first-stage scoop 3 provided in the inner cylinder 2. Air is supplied to the combustion zone as combustion air.

Reference numeral 2a is a hole provided at the end of the inner cylinder 2 for introducing air into the portion provided with the baffle 6, and 6a is provided in the baffle 6 for baffling the air from the hole 2a.
It is a hole to be introduced into the inner gap of.

[0007]

When the steam for NOx reduction is injected from a few holes formed in the front surface of the nozzle holder, as in the above-mentioned gas turbine combustor currently used, Combustion instability may occur and combustion oscillation may occur. The reason for this is that small oil droplets cannot go to the outside of the inner cylinder due to the accompanying flow of water vapor, and a large amount of water vapor enters the high temperature portion on the outer side, resulting in a decrease in temperature and carbon monoxide (O ₂ ) shortage. It is considered that CO is generated and that the oxygen (O ₂ ) deficiency causes combustion instability at the same time and the flame is turned on and off.

The instability of the flame (pressure fluctuation) resonates with the combustor, the passenger compartment, and the coupled acoustic eigenmode to affect the flow rate (flow velocity) of air and oil, further promoting the pressure fluctuation. It is considered to be a thing.

The present invention has been made to solve this drawback.

[0010]

In the gas turbine combustor of the present invention, fuel oil is discharged from a combustion nozzle held by a nozzle holder to a combustion region in an inner cylinder surrounded by an outer cylinder, on the front surface of the nozzle holder. The steam supplied to the steam passages of the nozzle holder through a plurality of holes bored radially outside the combustion nozzle is injected, and at the same time, the scoop provided on the inner cylinder and the nozzle holder and the inner cylinder are In a gas turbine combustor in which combustion air is supplied to the combustion region from the inside and outside gaps of the baffle provided between the baffle, the side surface of the nozzle holder communicates with the steam passage of the nozzle holder, and the gap inside and outside the baffle And a bypass hole for steam injection for mixing steam into the combustion air flowing in from the scoop.

In the present invention, part of the steam supplied to the steam passage of the nozzle holder flows out from the bypass hole, and the amount of steam injected from the hole formed in the front surface of the nozzle holder decreases. Therefore, the accompanying flow of water vapor is eliminated in the combustion region, and even small oil droplets in the inner part of the inner cylinder can escape to the outer part and oxygen (O ₂ ) in the outer part is discharged.
The shortage is resolved.

Further, since the bypass hole communicating with the steam passage in the nozzle holder is provided on the side surface of the nozzle holder, the steam is injected from the hole and mixed with the combustion air, and the inside and outside gaps of the baffle allow the inside of the combustion area to be mixed. In addition to reducing the temperature of the entire cylinder equally, the steam that has flowed out of the inner cylinder is partly mixed with the air flow between the outer cylinder and the inner cylinder and pushed back to the baffle part, and partly from the scoop. It flows into the combustion zone with the air flow. As a result, the high temperature region of the head in the gas turbine combustor can be entirely reduced in temperature.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. In this embodiment, the following configuration is added to the conventional gas turbine combustor shown in FIG. 3, and in FIGS. 1 and 2, the same parts as in FIG. However, the description of the parts that are not changed will be omitted.

In the present embodiment, the diameter of the steam passage 7 provided in the nozzle holder 4 and the diameter of the hole X provided in the front surface of the nozzle holder 4 are reduced, and the number thereof is reduced. The injection amount of water vapor injected from the front surface of the nozzle holder 4 to the combustion region in the inner cylinder 2 is set to 20
We are trying to reduce it by about%.

Further, on the side surface of the nozzle holder 4, there is provided a bypass hole Y which communicates with each steam passage 7 and is arranged so as to be orthogonal to the steam passage 7.
It is provided at a position corresponding to the hole 6 a of the baffle 6 and the hole 2 a of the inner cylinder 2.

In the present embodiment, as shown in FIG. 2, the fuel oil is jetted from the combustion nozzle 6 into a combustion region in the inner cylinder 2 as a small oil droplet as shown by a dotted arrow F. On the other hand, the combustion air flows between the outer cylinder 1 and the inner cylinder 2 in the direction of arrow A and flows into the scoop 3 and the hole 2a of the inner cylinder. At this time, N
The water vapor for Ox reduction flows out from the front hole X and the bypass hole Y, and the water vapor flowing out from the bypass hole Y is mixed with the combustion air flowing in from the hole 2a at the baffle 6,
It flows through the inner and outer gaps of the baffle 6 into the combustion region in the inner cylinder 2 in the direction of arrow A + S. Also, the bypass hole Y
A part of the steam flowing out from the inner cylinder flows through the hole 2a of the inner cylinder toward the scoop 3 between the outer cylinder 1 and the inner cylinder 2 and mixes with the combustion air. Inside, the rest is pushed back into the combustion air and returns to the baffle 6 again.

Therefore, in the present embodiment, oil drops, air and steam are evenly mixed and distributed in the combustor to lower the temperature.

Further, in the present embodiment, the hole diameter of the holes X provided on the front surface of the nozzle holder 4 is made smaller than that of the conventional gas turbine combustor, and the number thereof is reduced, and the steam passage is Since a part of the water vapor flowing through 7 is made to flow out from the bypass hole Y, the injection amount of the water vapor injected from the front surface of the nozzle holder 4 is reduced, and the accompanying flow of water vapor can be eliminated. The small oil droplets inside the combustion region inside the inner cylinder 2 can also escape to the outside, and the lack of oxygen (O ₂ ) outside the combustion region can be eliminated.

[0019]

According to the present invention, since steam can be mixed into the combustion air and supplied to the combustion region in the inner cylinder of the combustor, uneven distribution of steam in the combustion region can be eliminated and it can be partially performed. Oxygen (O ₂ ) deficiency will not occur. Further, since the state of the combustion region in the inner cylinder becomes uniform and the temperature is reduced as a whole, the instability of the flame is eliminated, so that the combustion oscillation can be prevented.

[Brief description of the drawings]

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

FIG. 2 is an operation explanatory view of a combustion region of the same embodiment.

FIG. 3 is a schematic diagram of a conventional gas turbine combustor.

[Explanation of symbols]

 1 Outer Cylinder 2 Inner Cylinder 3 Scoop 4 Nozzle Holder 5 Combustion Nozzle 6 Baffle 7 Steam Passage X Hole Y Bypass Hole

Claims (1)

[Claims] 1. A combustion area in an inner cylinder surrounded by an outer cylinder is provided with fuel oil from a combustion nozzle held by a nozzle holder at a portion radially outward of the combustion nozzle on the front surface of the nozzle holder. Water vapor supplied to the steam passage of the nozzle holder from the multiple holes is injected, and is burned from the scoop provided in the inner cylinder and the gap inside and outside the baffle provided between the nozzle holder and the inner cylinder. In a gas turbine combustor in which air is supplied to the combustion zone,
A gas characterized in that a vapor injection bypass hole is provided on a side surface of the nozzle holder, the vapor passage being in communication with the vapor passage of the nozzle holder, the vapor being mixed with the inner and outer gaps of the baffle and the combustion air flowing from the scoop. Turbine combustor.