JP2516822Y2 - Gas turbine combustor - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a combustor for a gas turbine, which is provided with a premixing portion of fuel and air and which can reduce NOx in combustion gas. .

[Conventional technology]

Conventional methods for reducing NOx in the combustion gas of a gas turbine include (1) water or steam injection, (2) improvement of combustion by two-stage combustion, (3) premixing / lean combustion, (4) catalytic combustion, Although considered, most of the methods (1) have been put to practical use so far.

The method (1) is a very simple method in which a water injection device or a steam injection device is attached to the fuel injection valve, but a water treatment device and a steam generation device are required as incidental equipment. When a large amount of water is injected, the NOx reduction rate increases, but instead, the unburned content such as CO also increases, so the reduction rate due to water injection is at most about 50%. Water injection also increases fuel efficiency.

The method (2) is a method of reducing NOx by changing the shape of the combustor and air distribution, but the reduction rate is 20 to 3
It is about 0%.

The methods (3) and (4) are methods in which a reduction rate of 60% or more can be expected. Method (4) is 90-100% if successful
NOx can be reduced, but there are many problems such as catalyst life, catalyst honeycomb durability, combustor structure, and system.

On the other hand, in the method (3), since the operating range at low NOx is narrow, it is necessary to use the variable mechanism device together, and the cost is increased. Also, since there is a high possibility of flashback to the premixing section,
There are 1 and 2 practical examples of gas fuel, but it has not been practically used for liquid fuel.

[Problems to be solved by the device]

In view of the above points, the present inventors have already developed a combustor as shown in FIG. That is, a large number of swirl vanes 1
The fuel injected from between is mixed with the swirling air in the premixing unit 2 and then burned in the combustion region 3. 4 is a primary fuel injection nozzle.

However, in the combustor shown in FIG. 5, the amount of swirling air entering the premixing section 2 is large, so the recirculation region is large and strong.
Therefore, the combustion gas enters the inside of the premixing unit to heat and burn the nozzle stator 5, and a stagnation region is generated. As a result, NOx cannot be significantly reduced.

The present invention has been made to solve the above points,
An object of the present invention is to provide a combustor for a gas turbine capable of preventing heating of a nozzle stator, reducing a stagnation area, and significantly reducing NOx in combustion gas.

[Means for Solving the Problems] In order to achieve the above object, the gas turbine combustor of the present invention has an outer cylinder 6 as shown in FIG. 1 and FIG.
An inner cylinder 7 is provided inside, and a pressurized air passage 8 is provided between the outer cylinder and the inner cylinder.
Is formed, the primary fuel injection nozzle 4 is attached to the axial center of the end of the inner cylinder, and the air inlet 10 for taking in pressurized air is provided in the peripheral portion of the end of the inner cylinder. A large number of swirl vanes 1 are attached to the swirl vanes, a main fuel injection nozzle 11 is inserted between these swirl vanes, and a premixing portion 2 communicating with the air intake 10 is formed around the outer periphery of the primary fuel injection nozzle 4. A combustion region 3 is provided on the downstream side of the premixing unit 2.
In the gas turbine combustor in which the dilution region 20 is formed on the downstream side of the combustion region 3, the partition plate 12 is provided in the premixing unit 2 in the axial direction of the inner cylinder to divide the premixing unit, and the primary fuel injection is performed. An air passage 13 for flowing seal air is formed between the nozzle stator 5 outside the nozzle 4 and the premixing portion 2 so as to cover the nozzle stator 5.

In addition, a flat air chamber 17 may be formed so as to cover the surface of the liner head 16 adjacent to the downstream side of the primary fuel injection nozzle 4.

Furthermore, an opening 21 for allowing air to flow into the inner cylinder 7 is provided in the pressurized air passage 8 in the dilution area 20 on the downstream side of the combustion area 3, and the opening 21 is opened / closed to adjust the amount of air flowing into the inner cylinder. The variable mechanism 22 for the above may be provided in the pressurized air passage 8.

[Action]

Liquid fuel or gas fuel is dispersed and injected from a main fuel injection nozzle 11 inserted between a large number of swirl vanes 1 to premix fuel and air (in the case of liquid fuel, premix). Pre-evaporation), and the stagnation area around the nozzle stator 5 is reduced by the partition plate 12 and the air seal, and the nozzle stator 5 is cooled to prevent fuel from returning, so that unburned components such as CO do not increase. Greatly reduces NOx.

Further, in the premixed combustion, since the flammable range is narrow, the variable mechanism 22 is attached to the dilution area 20 to expand the operating range.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. However, the shapes of the constituent members described in this embodiment, their relative arrangements, and the like are not intended to limit the scope of the present invention to them only, unless otherwise specified, and are merely examples. Only.

FIG. 1 shows an embodiment of the present invention, and FIG. 2 shows the details of the essential parts thereof. An inner cylinder 7 is provided inside the outer cylinder 6, and a pressurized air passage 8 is formed between the outer cylinder 6 and the inner cylinder 7. The primary fuel injection nozzle 4 is attached to the axial center of the end of the inner cylinder 7, and an air intake 10 for taking in pressurized air is provided in the peripheral portion of the end of the inner cylinder 7. Inside this air intake 10. A large number (24 as an example) of the swirl vanes 1 are attached, and a large number (12 as an example) of the main fuel injection nozzles 11 are inserted and fixed between these swirl vanes. Further, a premixing section 2 communicating with the air intake 10 is formed around the outside of the primary fuel injection nozzle 4.

Further, a partition plate 12 is provided in the premixing portion 2 along the fluid flow in the axial direction of the inner cylinder to divide the premixing portion into an inner annular passage and an outer annular passage, and the primary fuel injection nozzle 4
An air passage 13 for flowing seal air is formed between the nozzle stator 5 on the outer side of and the inner annular passage of the premixing section 2. In this example, the periphery of the nozzle stator 5 of the primary fuel injection nozzle 4 is covered with a seal air intake pipe 14 to form an air passage 13. 15 is a seal air intake.

A flat air chamber 17 is formed so as to cover the surface of the liner head 16 adjacent to the downstream side of the primary fuel injection nozzle 4. 18 is a small hole for taking in air.

Further, an opening 21 for allowing air to flow into the inner cylinder 7 is provided in the pressurized air passage 8 in the dilution area 20 on the downstream side of the combustion area 3, and the opening 21 is opened / closed to adjust the amount of air flowing into the inner cylinder 7. For this purpose, the variable mechanism 22 is provided in the pressurized air passage 8. twenty three
Is a variable port, 24 is a dilution hole, and 25 is a spark plug.

In the gas turbine combustor configured as described above, the discharge air from the compressor (not shown) passes through the pressurized air passage 8 between the inner cylinder 7 and the outer cylinder 6 of the combustor in FIG. It flows from right to left and flows from the air intake 10 into the premixing section 2, the combustion zone 3 and the dilution zone 20.

Ignition of the fuel is performed by the primary fuel injection nozzle 4 and the spark plug 25. A few seconds after ignition, many swirl vanes 1
The main fuel is injected from a large number of main fuel injection valves 11 mounted between. In the premixing section 2, the fuel and air are swirled and premixed, and after entering the combustion region 3, they are efficiently burned.
The partition plate 12 and the air seals are attached to reduce the stagnation area due to turning that causes flashback.

The combustion gas in the combustion region 3 is diluted and temperature-uniformized in the dilution region 20, and then flows into a turbine (not shown).

In the variable mechanism 22, the variable port operates so that the premixing ratio of the fuel and air in the premixing unit 2 becomes constant regardless of load fluctuations such as changes in the air-fuel ratio.

Next, the results of experiments conducted by the inventors will be described. Fig. 3 shows the air / fuel ratio (A /
The relationship between F), CO (ppm) in combustion gas, NOx (g / kg fuel), and total pressure loss coefficient (φ _C ) is shown. Pressure is 3 atm (absolute), temperature is 320 ℃, maximum cross-section average flow velocity is 20.56 m / s
Met. Also, as the opening degree of the variable mechanism, 0%, 31%, 63
%, 100%. As is clear from FIG. 3, NOx in the combustion gas was reduced to 3 g / kg fuel or less.

Fig. 4 shows the air-fuel ratio and CO (ppm), NOx (g / kg fuel) in the combustion gas, and the variable mechanism opening in the combustor of the present invention and the conventional combustor (shown in Fig. 5). It shows the relationship with the degree (%). As is clear from FIG. 4, when the combustor of the present invention is used, NOx in the combustion gas is 3 (g / k
(g fuel) was reduced to below.

[Effect of device]

Since the present invention is configured as described above, the following effects can be obtained.

(1) By providing a partition plate in the premixing section, the stagnation area around the nozzle stator can be reduced, and the nozzle stator is cooled by providing an air passage for taking in seal air so as to cover the nozzle stator. In addition to this, the amount of heat input can be reduced by moving the combustion gas away, and NOx in the combustion gas can be significantly reduced without overheating the premixing section.

(2) When the liner head has the laminated cooling structure and the impingement cooling and the convection cooling method are adopted, the cooling can be performed without flowing the cooling air into the upstream portion of the combustion region, so that the air-fuel ratio in the combustion region is constant, and It is possible to suppress an increase in unburned components such as CO due to cooling of the cooling air.

(3) When the variable mechanism of the amount of air flowing into the inner cylinder in the dilution region is provided, the ratio of fuel and air in the premixing section can be made constant regardless of load fluctuation.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional explanatory view showing an embodiment of a gas turbine combustor of the present invention, and FIG. 2 is an enlarged explanatory view showing details of a premixing section and a combustion region and a fluid flow in FIG.
FIG. 3 is a diagram showing the relationship between the air / fuel ratio and the CO and NOx total pressure loss coefficients in the combustion gas in the combustor of the present invention, and FIG. 4 is the combustor of the present invention and the conventional combustor. FIG. 5 is a diagram showing the relationship between the air / fuel ratio and the CO / NOx variable mechanism opening in the combustion gas, and FIG. 5 is an explanatory diagram showing an example of a conventional combustor. 1 ... Swirl blade, 2 ... Premixing section, 3 ... Combustion area, 4
...... Primary fuel injection nozzle, 5 ...... Nozzle stator, 6 ...
... Outer cylinder, 7 ... Inner cylinder, 8 ... Pressurized air passage, 10 ... Air inlet, 11 ... Main fuel injection nozzle, 12 ... Partition plate, 13 ...
… Air passage, 14 …… Seal air intake pipe, 15 …… Seal air intake, 16 …… Liner head, 17 …… Air chamber, 18 ……
Small hole, 20 …… dilution area, 21 …… opening, 22 …… variable mechanism,
23: Variable port, 24: Dilution hole, 25: Spark plug

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiro Kinoshita 1-1 Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries, Ltd. Technical Research Institute (56) Reference JP-A-50-140716 (JP, A) JP 55-148151 (JP, A) JP 62-218732 (JP, A) Actually developed 61-39273 (JP, U)

Claims (3)

(57) [Scope of utility model registration request] 1. An outer cylinder (6) is provided with an inner cylinder (7) to form a pressurized air passage (8) between the outer cylinder and the inner cylinder, and a primary portion is provided at an axial center of an end portion of the inner cylinder. A fuel injection nozzle (4) is attached, an air intake (10) for taking in pressurized air is provided in the peripheral portion of the end of the inner cylinder, and a large number of swirl vanes (1) are attached in this air intake. The main fuel injection nozzle (11) is inserted between these swirl vanes, and a premixing section (2) communicating with the air intake (10) is formed around the outer periphery of the primary fuel injection nozzle (4). In a combustor for a gas turbine in which a combustion region (3) is formed on the downstream side of the premixing section (2) and a dilution region (20) is formed on the downstream side of the combustion region (3), the premixing section (2) is provided. A partition plate (12) is provided in the axial direction of the inner cylinder to divide the premixing section, and the primary fuel injection nozzle (4) is further provided.
For a gas turbine, characterized in that an air passage (13) for flowing seal air is formed between the nozzle stator (5) and the premixing portion (2) outside the nozzle so as to cover the nozzle stator (5). Combustor. 2. The combustion for a gas turbine according to claim 1, wherein the flat air chamber (17) is formed so as to cover the surface of the liner head (16) adjacent to the downstream side of the primary fuel injection nozzle (4). vessel. 3. A dilution area (20) downstream of the combustion area (3).
An opening (21) for allowing air to flow into the inner cylinder (7) is provided in the pressurized air passage (8) in, and a variable mechanism for opening and closing this opening to adjust the amount of air flowing into the inner cylinder ( The combustor for a gas turbine according to claim 1 or 2, wherein 22) is provided in the pressurized air passage (8).