JPH05149543A - Burner of gas turbine - Google Patents

Abstract

PURPOSE:To restrain the generation of CO and unburnt hydrocarbon UHC in a burner by a method wherein the burner is provided with an annular choking member, mounted concentrically on the inner cylinder at the rear part of combustion and having a conical truncated shape. CONSTITUTION:A truncated conical ring type intermediate choke 14 is attached to the rear stream side of a ring 8 having a scoop 6 in the axial intermediate part of an inner cylinder. The intermediate choke 14 is welded to another ring 9 and is reinforced by reinforcing plates 15, 16. The intermediate choke 14 is attached to a position satisfying the relation of l2/l1>0.15 from the cooling surface of the wall of the inner cylinder when l1 shows a distance from the entrance of a skirt 2 to a second scoop and l2 shows a distance from the scoop 6 to the outlet port of the intermediate chake 14. According to this method, the burning reaction of gas, which flows near the wall of the inner cylinder, is promoted and the generation of CO and the like in the burner can be restrained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine combustor applied to thermal power generation and the like.

[0002]

2. Description of the Related Art FIG. 4 is an explanatory diagram of a conventional combustor of an annular can gas turbine used for thermal power generation. In the drawing, the present combustor is generally called a diffusion type, and the inlet of this inner cylinder is formed by a flange 1, skirts 2, 3, a ring 4, etc., and is connected to a fuel nozzle (not shown) to form an annular combustor. It is attached to the outer cylinder. A ring 7 having six scoops 6 is welded to the ring 4 via a louver 5, and a ring 8 having a scoop 6 is welded to the ring 7 via a louver 5. Similarly, the ring 9 is sequentially welded through the louver 5 below, and the spring clip 10 and the outlet throttle 11 are integrally formed at the outlet thereof. The scoop 6 introduces combustion air into the center of the inner cylinder to burn the fuel, and the louver 5 forming a corrugated plate forms an air flow along the inner wall of the inner cylinder to perform film cooling of the inner cylinder.
The spring clip 10 telescopically fits the rear edge of the inner cylinder to the tail cylinder, and the outlet throttle 11 rectifies the flow of the combustion gas transitioning from the inner cylinder to the tail cylinder. The hole 12 formed in the ring 7 communicates with a hole in another adjacent inner cylinder via a connecting pipe to form a frame holder. Reference numeral 13 is a rib that supports the outlet throttle 11.

[0003]

In the conventional gas turbine combustor as described above, steam or water is injected into the combustor as a means for reducing NOx. However, in order to reduce NOx, steam or water is injected. The injection increases the production of CO and unburned hydrocarbons UHC in the combustor. This is because the flame becomes longer by injecting steam or water,
This is because the portion of the flame near the inner cylinder wall mixes with the air layer for film cooling that flows near the inner cylinder wall, and the combustion reaction stops incomplete on the way.

[0004]

SUMMARY OF THE INVENTION A gas turbine combustor according to the present invention aims to solve the above-mentioned problems, and is a conical trapezoidal ring-shaped throttle that is concentrically mounted on the inner cylinder wall behind the combustion zone. It is characterized by a configuration including members.

[0005]

That is, in the combustor of the gas turbine according to the present invention, a frustoconical ring-shaped throttle member is concentrically mounted on the inner cylinder wall at the rear of the combustion area, and the inner cylinder wall is formed by this throttle member. The air layer that flows in the vicinity and cools the film moves toward the center of the inner cylinder and mixes with the high-temperature gas that flows in the center of the inner cylinder. The gas flowing in the vicinity of the inner cylinder wall in the state comes into contact with the high-temperature gas flowing in the central portion of the inner cylinder to promote the combustion reaction.

[0006]

1 and 2 are explanatory views of a combustor of a gas turbine according to an embodiment of the present invention, and FIG. 3 is an explanatory view of a combustor according to another embodiment of the present invention. In FIG. 1, the combustor of the gas turbine according to this embodiment is a combustor of an annular can type gas turbine used for thermal power generation and is generally called a diffusion type. The inlet of this inner cylinder is a flange 1, skirts 2, 3 , Ring 4, etc., and is connected to a fuel nozzle (not shown) and attached to the outer cylinder of the annular combustor. A ring 7 having six scoops 6 is welded to the ring 4 via a louver 5, and a ring 8 having a scoop 6 is welded to the ring 7 via a louver 5. Similarly, the ring 9 is successively welded via the louver 5 in the following, and the spring clip 10 and the outlet throttle 11 are integrally formed at the outlet thereof. The scoop 6 introduces combustion air into the center of the inner cylinder to burn the fuel, and the louver 5 forming a corrugated plate forms an air flow along the inner wall of the inner cylinder to perform film cooling of the inner cylinder. The spring clip 10 telescopically fits the rear edge of the inner cylinder to the tail cylinder, and the outlet throttle 11 rectifies the flow of the combustion gas transitioning from the inner cylinder to the tail cylinder. The hole 12 formed in the ring 7 communicates with the hole of another adjacent inner cylinder via the connecting pipe to form a frame holder. Reference numeral 13 is a rib that supports the outlet throttle 11.

In such a combustor, steam or water is injected into the combustor as a means for reducing NOx.
By injecting steam or water to reduce NOx, the flame becomes longer, and the part of the flame near the inner cylinder wall mixes with the air layer for film cooling that flows near the inner cylinder wall, and the combustion reaction is incomplete on the way. Since the generation of CO and unburned hydrogen UHC in the combustor increases due to the still stop, the inner cylinder of the present combustor has a scoop 6 at the axially intermediate portion of the inner cylinder as shown in the figure. A ring-shaped intermediate diaphragm 14 forming a truncated cone is attached to the downstream side of the ring 8 having The intermediate throttle 14 is welded to the ring 9 and is reinforced by the reinforcing plates 15 and 16. The arrows indicate the flow directions of air and gas. The intermediate restriction 14 the mounting position, l ₁ the distance from the entrance of the skirt 2 to the second scoop, and the distance from the scoop 6 to an outlet of the intermediate diaphragm 14, l _2, the values of l ₁ / l ₂ is From the cooling surface of the inner cylinder wall, l ₂ / l ₁ > 0.15.

As described above, the truncated cone is formed in the axially intermediate portion of the inner cylinder.
By attaching the ring-shaped intermediate diaphragm 14 forming
The air layer that flows near the inner cylinder wall and cools the film is inside the inner cylinder.
Mixes with the hot gas flowing through the core towards the core
It As a result, the combustion reaction stops once and
The gas flowing near the inner cylinder wall, which is in the state of flowing, flows through the center of the inner cylinder.
The combustion reaction is accelerated again by contact with the hot gas
As shown in 2, the generation of CO and unburned hydrocarbon UHC is suppressed.
Can be controlled. Especially, the amount of NOx generated is extremely low.
It has an effect in the low NOx combustor to reduce the generation of NOx.
Low pollution with raw 25ppm and CO generation less than 2ppm
A combustor is obtained. The data in the figure is used as fuel.
Using natural gas, l₁= 240 mm, l₂= 95 mm,
l₂/ L ₁It shows the case where the test was conducted with = 0.4. Well
The intermediate throttle 14 is not the outlet throttle 11 as shown in FIG.
It can also be applied to gas turbine combustors
It has substantially the same operational effect as when the diaphragm 11 is provided.

[0009]

The gas turbine combustor according to the present invention is configured as described above, and since the combustion reaction of the gas flowing near the inner cylinder wall is promoted, CO and unreacted gas in the combustor of the gas turbine are promoted. Generation of fuel hydrocarbon UHC is suppressed.

[Brief description of drawings]

FIG. 1 (a) is a vertical sectional view of a combustor of a gas turbine according to an embodiment of the present invention, and FIG. 1 (b) is a vertical sectional view of an intermediate throttle thereof.

FIG. 2 is an explanatory view of its operation.

FIG. 3 is a vertical cross-sectional view of a combustor of a gas turbine according to another embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view of a conventional gas turbine combustor.

[Explanation of symbols]

 1 flange 2 skirt 3 skirt 4 ring 5 louver 6 scoop 7 ring 8 ring 9 ring 10 spring clip 11 outlet throttle 12 hole 13 rib 14 intermediate throttle 15 reinforcement plate 16 reinforcement plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiko Miyazaki 2-1-1, Niihama, Arai-cho, Takasago-shi, Hyogo Mitsubishi Heavy Industries, Ltd. Takasago Plant

Claims (1)

[Claims] 1. A combustor for a gas turbine, comprising a conical trapezoidal ring-shaped throttle member mounted concentrically on an inner cylinder wall at the rear of the combustion zone.