JP2001280155A - Gas turbine fuel injection method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection device capable of supplying atomized fuel having few flow amount and high pressure even in ignition and low load regions of a gas turbine. SOLUTION: In the ignition and low load region, high pressure adding air is led from a port 45. Adding air passes an inner space 35, and liquid fuel having few flow rate is atomized. Feeding of adding air is stopped in association with increase of engine rotating speed, and a normal operation is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a fuel injection device used for a gas turbine.

[0002]

2. Description of the Related Art In order to continuously operate a gas turbine satisfactorily throughout the entire region, it is necessary to atomize (atomize) fuel and secure a flow rate corresponding to the operating region (load region) to supply the fuel to a combustion chamber. is there. For this reason, various fuel injection devices for supplying fuel to the combustion chamber have been conventionally provided.

In general, there are two types of fuel injection systems: a pressure spray system (hereinafter, referred to as a "pressure system") and an air flow atomization system (hereinafter, referred to as an "air flow system"). In the pressure method, the fuel is brought into a high-pressure state and atomized by injecting the fuel from a nozzle, and the fuel flow rate adjustable range is narrow. In the air flow method, fuel is brought into contact with high-speed air (air for atomization) to atomize the fuel, and the fuel flow rate adjustable range is wide.

When starting the gas turbine (ignition to low rotation range)
In, the fuel needs to be set at a very low flow rate. For this reason, it is preferable to inject and supply a small amount of fuel by the pressure method at the time of starting. On the other hand, during operation (ignition to full load range), it is necessary to supply an amount of fuel (turndown ratio is 1:20 to 40) according to each operation condition.

However, in the pressure system, since the fuel pressure is proportional to the square of the flow rate (fuel supply amount), it is necessary to apply a high pressure to atomize and supply the fuel while covering the turndown ratio. is there. For this reason, in order to secure the required fuel flow rate in the entire region, the fuel must be extremely high in the entire load region, and the fuel injection device becomes large in size to secure the strength, and the weight increases, which is not practical.

[0006] For this reason, in the past, an airflow system has been adopted in the no-load to full-load region. That is, the conventional fuel injection device is often configured by providing two types of nozzles, ie, a pressure type nozzle and an airflow type nozzle.

[0007]

However, such a conventional fuel injection device has a complicated structure, which increases the weight and the manufacturing cost.

Accordingly, a first object of the present invention is to adopt only an airflow system which can achieve good atomization of fuel even when the injection pressure is low, and it is possible to secure a good supply of fuel over the entire area. An object of the present invention is to provide a fuel injection method for a gas turbine.

A second object of the present invention is to provide an inexpensive and lightweight fuel injection device for a gas turbine for using the above method.

[0010]

Means for Solving the Problems (1) In order to achieve the first object of the present invention, the invention according to the present application is to form a thin film ring by rotating liquid fuel around a predetermined fuel injection direction. By supplying combustion air swirled around the fuel injection direction to the inside and outside of the thin-film annular fuel, the liquid fuel is atomized to be supplied to the combustion chamber of the gas turbine. A fuel injection method for a turbine, characterized in that the additional air that joins the combustion air supplied to the inside is supplied only when the gas turbine is started.

According to this configuration, when the gas turbine is not loaded (during start-up), the flow rate is small (for example, 5 CC / sec to 20 CC / sec).
S) of liquid fuel, and the liquid fuel is swirled along the fuel supply direction to form a thin film ring, and a required pressure (for example, 0.2 to 0.5 MPa) is supplied by an additional air supply means.
) Is supplied to the inside of the thin-film annular fuel. Thereby, the added air at the required pressure merges with the combustion air sucked by the compressor of the gas turbine, and the fuel is atomized under the above pressure and sent to the combustion chamber.

When the gas turbine starts a steady operation, a large amount of combustion air is taken in by a compressor of the gas turbine and atomizes the liquid fuel formed in the thin-film annular shape, so that the additional air supply means is stopped. Then, the supply of the additional air is stopped. Since the combustion air taken in by the compressor is supplied to the inside and outside of the fuel formed in the thin-film annular shape, it is possible to satisfactorily atomize the fuel.

[0013] In particular, the pressure of the added air is from 0.2 MPa to 0.1 MPa.
When the pressure is set to 5 MPa, compressed air for an air tool installed in a factory or the like can be used as additional air when an industrial gas turbine is used.

(2) In order to attain the second object of the present invention, the invention according to the present application forms a thin film ring by rotating liquid fuel around a predetermined fuel injection direction, and forms the thin film ring. By supplying combustion air swirled around the fuel injection direction to the inside and outside of the formed fuel, the liquid fuel is atomized and supplied to a combustion chamber of a gas turbine to be injected into a combustion chamber of the gas turbine. And an additional air supply means for supplying additional air that merges with the combustion air supplied to the inside.

According to this structure, first, at the time of starting the gas turbine, a liquid fuel of a small flow rate (for example, 5 CC / sec to 20 CC / sec) is supplied, and the liquid fuel is swirled along the fuel supply direction to form a thin film ring. At the same time, additional air at a required pressure (for example, 0.2 MPa to 0.5 MPa) is supplied to the inside of the thin-film annular fuel by the additional air supply means. As a result, the fuel is combined with the combustion air sucked by the compressor of the additional air gas turbine at the required pressure, and the fuel is atomized under the pressure and sent to the combustion chamber.

When the gas turbine starts steady operation, a large amount of combustion air is taken in by the compressor of the gas turbine and atomizes the liquid fuel formed in the thin film annular shape, so that the additional air supply means is stopped. Then, the supply of the additional air is stopped. Since the combustion air taken in by the compressor is supplied to the inside and outside of the fuel formed in the thin-film annular shape, it is possible to satisfactorily atomize the fuel.

Here, there is provided air swirling means for swirling the added air in the same direction as combustion air (hereinafter appropriately referred to as "inside air") supplied to the inside of the annularly formed fuel. Thereby, atomization of the fuel can be further improved.

Further, by providing a guide nozzle for guiding the additional air to the inside air in the additional air supply means, the additional air can be surely combined with the combustion air. Further, by projecting the guide nozzle portion toward the airflow side formed by the inside air, the joining of the added air can be made more reliable.

Further, the guide nozzle section is provided with a nozzle for receiving the supply of the additional air and an additional air guide rod provided at the tip of the nozzle, so that the additional air can be reliably supplied along the guide rod. To the inside air.
This makes it possible to further ensure that the added air joins the combustion air.

[0020]

Embodiments of the present invention will be described below.

FIG. 1 is an external perspective view of a fuel injection device according to one embodiment of the present invention, and FIG. 2 is a sectional view showing the internal structure of the fuel injection device.

The outline of the fuel injection device 10 will be described with reference to these drawings.

The fuel injection device 10 includes a base 11 and an injection unit 1.
2 and a flange portion 13 is formed on the base portion 11. The fuel injection device 10 is installed in a combustion chamber of a gas turbine, and injects and supplies fuel from an injection unit 12 into the combustion chamber. The installation of the fuel injection device 10
This is performed by inserting the injection section 12 into the combustion chamber of the gas turbine and fixing the flange section 13 to the periphery of the inlet of the combustion chamber. In the present embodiment, the fastening bolt insertion hole 14
The flange 13 and the inlet peripheral edge of the combustion chamber are fastened and fixed by inserting a bolt through the bolt and tightening the bolt.

The feature of this embodiment lies in the fuel supply system. That is, the fuel injection device 10
The fuel is atomized and supplied only by a so-called air flow method, and the additional air supply mechanism 1 provided in the base 11 is provided.
The point is that the additional air at a predetermined pressure is forcibly sent to the combustion chamber when the gas turbine is started by 5 (additional air supply means). As a result, good fuel supply corresponding to the entire operation range from the start of the gas turbine can be performed, and the structure of the fuel injection device 10 can be simplified because only the air flow system is adopted, and the fuel injection device 10 can be manufactured at low cost. That can be provided. The details will be described below.

(1) The base 11 includes a main body 16, an end plate 17, and an additional air supply mechanism 15.
FIG. 3 is a sectional view taken along the line AA in FIG. Figure 1
This will be described with reference to FIG.

The end plate 17 is attached to the rear end face of the main body 16. The end plate 17 has a disk shape as shown in FIG. 3, and has four through holes 19 radially with respect to the center. This through hole 19
Constitute the fastening bolt insertion hole 14 described above. Eight fuel supply holes 20 are provided radially with reference to the center of the end plate 17. Each fuel supply hole 20
Each of the fuel supply holes 20 is formed with a port 21 for connecting a fuel pipe (not shown), as shown in FIG.
In the present embodiment, four through holes 19 and eight fuel supply holes 20 are provided, but it is a matter of course that the present invention is not limited to this number. In the center of the end plate 17, an opening 2 centered on the center of the end plate 17 is provided.
2 are formed through. The opening 22 is configured to receive an air guide pipe 23 of the additional air supply mechanism 15 described later.

Referring to FIG. 2, main body 16 is formed in a cylindrical shape, and a flange 24 is formed at a rear end thereof.
The flange 24 constitutes the flange 13 described above. Four through holes 40 are formed in the flange 24.
These through holes 40 and the through holes 1 of the end plate 17 are provided.
9 is set to have the same diameter, so that the centers of the holes coincide with each other. Therefore, the above-described fastening bolt insertion hole 14 is formed by the through hole provided in the flange portion 24 and the through hole 19.
Is configured.

A through hole 25 is formed at the center of the main body 16 along the longitudinal direction of the main body 16. This through hole 25
Is set to have the same diameter as the opening 22 of the end plate 17, and the through hole 25 and the opening 22 exactly match with the end plate 17 attached to the main body 16. The through hole 25 and the opening 22
A supporting portion for supporting the additional air supply mechanism 15 is formed by the above and the additional air supply mechanism 15 is supported by the base 11 as described later.

On the rear end face of the main body 16, eight fuel guide holes 26 are formed corresponding to the fuel supply holes 20 of the end plate 17. That is, in a state where the end plate 17 is attached to the main body 16, the fuel supply hole 20 and the fuel guide hole 26 exactly match, and the fuel supplied to the port 21 is guided inside the main body 16 to the front end side. It has become. Each fuel guide hole 26 penetrates to the front end surface of the main body 16, and eight corresponding openings 27 are formed in the front end surface of the main body 16. Note that a pipe member 28 is fixed to each opening 27, and the fuel guided to the opening 27 is further guided to the injection unit 12 side through the pipe member 28.

(2) Next, the injection section 12 is formed in a cylindrical shape as a whole as shown in FIG. 1, and has an outer cylindrical section 29 and an inner cylindrical section 30 (see FIG. 2). FIG.
It is BB sectional drawing in. This will be described with reference to FIGS.

The inner cylinder 30 is a pipe-shaped member having a flange 31 formed at the base end. On the other hand, the outer tubular portion 29 is also a pipe-shaped member having a flange 32 formed at the base end. Then, the inner cylindrical portion 30 is inserted from the base end side of the outer cylindrical portion 29 to form the flange 3.
1 is brought into contact with the flange 32, and the inner cylinder 30 is
Attached to. Eight through holes 33 are formed in the flange 31 of the inner cylindrical portion 30. The pipe member 28 is connected to each through hole 33. Thus, the fuel supplied and guided to the pipe member 28 is further sent to the injection unit 12 side.

An opening 34 is formed at the center of the flange 31 of the inner cylinder 30, and an inner space 35 is formed inside the inner cylinder 29 to communicate with the opening 34. This opening 34
Functions as an intake of fuel combustion air, and the intake air is sent along the internal space 35. A swirler 36 (air swirling means) is provided in the internal space 35 as described later. Thus, the internal space 3
By means of 5, the intake combustion air forms an airflow.

The outer cylindrical portion 29 is further formed in a double-layer cylindrical shape. More specifically, referring to FIGS. 1 and 2, a plurality of intake ports 37 are formed around the flange 32, and an intake path 38 is formed continuously with each of the intake ports 37. The intake passage 38 is formed in a tubular shape inside the outer tubular portion 29. Each intake port 37 has a swirler 3
9 is provided, and the air taken in from the intake port 37 becomes a swirling flow swirling around the longitudinal direction of the outer cylinder portion 29 by the swirler 39, and this swirling flow is
Flow along 8. The air taken in from each intake hole 37 is used for fuel combustion in the same manner as the air taken in from the opening 34 (that is, used as combustion air).

When the inner cylinder 30 is inserted into the outer cylinder 29, a gap 41 is formed between them as shown in FIG.
The gap 41 is formed in an annular shape, and communicates with each pipe member 28. Therefore, the pipe member 2
The fuel supplied and guided by 8 enters this gap 41 and is sent to the tip end side of the injection unit 12 through the gap 41. Here, the distal end side of the gap 41 is spirally formed along the axial direction. As a result, the fuel sent to the distal end is swirled around its axial direction, and is formed into a thin annular shape.

Therefore, the combustion air is sent to the inside and outside of the thin-film annular fuel.

(3) Next, the additional air supply mechanism 15 will be described with reference to FIGS.

The additional air supply mechanism 15 includes a main body 42 and a guide rod 43 (addition air guide rod).

The main body 42 is provided with the air guide pipe 23 described above.
And a port 45 connected to the rear end of the air guide pipe 23.
And a nozzle 46 provided at the tip of the air guide pipe 23.
And

The air guide pipe 23 is connected to the end plate 1
7 is fitted into a housing space formed by the opening 22 of the main body 7 and the through-hole 25 of the main body 16. Port 45
Is a portion for taking in additional air from the outside. For example, in a factory or the like, compressed air for an air tool is supplied.

As shown in FIG. 2, the nozzle 46 is formed in a so-called stepped pipe having a reduced diameter at the tip end. The rear end side of the nozzle 46 is inserted exactly into the accommodation space, and the rear end surface is fixedly in contact with the front end surface of the air guide pipe 23. The reduced-diameter tip of the nozzle 46 is connected to the opening 34 of the inner cylinder 30 of the injection unit 12.
Side, that is, to the air flow side formed by the combustion air sent to the internal space 35 from the opening 34. The function and effect of the protruding tip of the nozzle 46 will be described later.

FIG. 4 is a sectional view taken along the line BB in FIG. Referring to FIGS. 2 and 4, guide bar 43 is formed by an elongated bar having a circular cross section. The rear end of the guide rod 43 is formed in a circular flange shape, and this portion is fitted into the tip end of the nozzle 46 exactly. Guide rod 4
Numeral 3 is inserted substantially coaxially into the inner cylindrical portion 30, and its distal end extends to near the distal end of the injection section 12. Thus, the air in the internal space 35 is satisfactorily fed along the guide rod 43.

As shown in FIG. 4, a hole 47 penetrating in the axial direction is formed at the rear end of the guide rod 43. In the present embodiment, four holes 47 are provided, but the number is not limited thereto, and the holes 47 are formed so that the additional air can be sent from the nozzle 46 to the internal space 35. It should just be.

The above-mentioned swirler 36 (air swirling means) is provided at an intermediate portion of the guide rod 43. The swirler 36 is for turning the combustion air taken in from the opening 34 clockwise or counterclockwise around the longitudinal direction of the inner cylinder 30. The additional air guided to the internal space 35 is swirled by the swirler 36 together with the combustion air taken in from the opening 34, and is sent to the front end side.

(4) Next, the operation of the fuel injection device 10 according to the present embodiment will be described together with the operation and effect.

Referring to FIGS. 1 and 2, in this fuel injection device 10, fuel (liquid fuel) is injected from port 21 through fuel guide hole 26 through pipe member 28 to injection section 12.
Sent to the side. The fuel sent to the injection unit 12 side
1 to form a thin film ring. On the other hand, air (combustion air) is taken in from the intake port 37 and the opening 34 simultaneously with the fuel. You. As a result, combustion air swirling in opposite directions to each other is sent to the inside and the outside of the fuel formed in the thin-film annular shape, and the fuel is atomized by the airflows of both. That is, the fuel injection device 10 according to the present embodiment employs only the airflow method.

Incidentally, in the gas turbine in which the fuel injection device 10 is used, it is necessary to suppress the supplied fuel to a small amount (for example, 5 CC / sec to 20 CC / sec) when there is no load (during start-up). However, when fuel is supplied by an airflow method, a small amount of fuel cannot be atomized well. This is because the engine speed is low in the no-load to low-load range, and a sufficient amount of combustion air cannot be taken.

However, in this embodiment, the additional air can be introduced by the additional air supply mechanism 15 in the range from ignition to low load. This added air is supplied to port 45
From the nozzle 46 through the air guide pipe 23 into the guide space 35 of the injection unit 12. As the added air, compressed air for an air tool can be used, and a pressure of about 0.2 to 0.5 MPa can be employed.

The high-pressure added air is supplied to the inside of the thin-film annular fuel through the internal space 35. As a result, the high-pressure additive air merges with the combustion air, and the fuel is atomized under the pressure and sent to the combustion chamber.

Thereafter, when the gas turbine starts steady operation, a large amount of combustion air is sent by the compressor of the gas turbine and the fuel is atomized satisfactorily. Stop feeding.
The air sent by the compressor is supplied to the inside and outside of the fuel formed into a thin film ring as described above, so that the fuel can be satisfactorily atomized.

In particular, in the present embodiment, the swirler 36 is provided, and the additional air can be swirled in the same direction as the combustion air supplied inside the fuel. Accordingly, there is an advantage that the momentum of the swirling airflow of the inside air increases, and the atomization of the fuel can be further improved.

In order to supply the additional air, the nozzle 4
6, the added air can be surely combined with the combustion air. In addition, since the nozzle 46 protrudes toward the opening 34, the added air is supplied to the internal space 35.
It can more reliably merge with the airflow formed inside. Thereby, the atomization of the fuel can be further improved.

As described above, the present embodiment employs a method in which high-pressure additional air is supplied only when the gas turbine is started. can do. Moreover, in the operating range after the start, the fuel can be supplied by the normal airflow method. Therefore, in the entire operation area of the gas turbine, appropriate continuous fuel supply can be performed only by the airflow method to achieve good continuous operation, and the structure of the fuel injection device 10 can be simplified and inexpensive.

[0053]

As described above, according to the present invention,
The following effects are obtained. When the gas turbine is started (ignited), the load is in the no-load range, so the flow rate of fuel to be supplied must be very small. On the other hand, if the pressure of the supplied fuel is low at the time of starting, starting (ignition) cannot be performed. However, in the present invention, by supplying the additional air at the time of starting, it is possible to supply minute fuel having a pressure necessary for starting, so that starting can be reliably performed. In addition, in the operating region after the start, by stopping the supply of the additional air, the supply of the fuel can be performed by the normal airflow method.

As described above, according to the present invention, it is possible to perform a good continuous operation by performing appropriate fuel supply by the airflow method in the entire operation range of the gas turbine.
Since the conventional pressure method and airflow method are not used together, the structure can be simple and inexpensive.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a fuel injection device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a fuel injection device according to one embodiment of the present invention.

FIG. 3 is a sectional view taken along the line AA in FIG. 2;

FIG. 4 is a sectional view taken along arrow BB in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Fuel injection device 11 Base 12 Injection part 15 Addition air supply mechanism 23 Air guide pipe 34 Opening 35 Internal space 36 Swirler 42 Main body 43 Guide rod 46 Nozzle

Claims (7)

[Claims] 1. A liquid fuel is swirled around a predetermined fuel injection direction to form a thin film annular shape, and swirled around the fuel injection direction inside and outside of the fuel formed into the thin film annular shape. A gas turbine fuel injection method for atomizing the liquid fuel by supplying combustion air and injecting the liquid fuel into a combustion chamber of a gas turbine, wherein the additional air that merges with the combustion air supplied to the inside, A fuel injection method for a gas turbine, wherein the fuel is supplied only when the gas turbine is started. 2. The fuel injection method for a gas turbine according to claim 1, wherein the pressure of the additional air is 0.2 MPa to 0.5 MPa. 3. The liquid fuel is swirled around a predetermined fuel injection direction to form a thin film ring, and is swirled around the fuel injection direction inside and outside the thin film formed fuel. A gas turbine fuel injection device that atomizes the liquid fuel by supplying combustion air and injects the atomized liquid fuel into a combustion chamber of a gas turbine, and supplies additional air that merges with the combustion air supplied to the inside. A fuel injection device for a gas turbine, comprising an additional air supply means for supplying air. 4. The fuel injection device for a gas turbine according to claim 3, further comprising air swirling means for swirling the additional air in the same direction as the combustion air supplied to the inside. Gas turbine fuel injection device. 5. The fuel injection device for a gas turbine according to claim 3, wherein the additional air supply means includes a guide nozzle for guiding the additional air to the combustion air supplied to the inside. A fuel injection device for a gas turbine, comprising: 6. The gas injection device for a gas turbine according to claim 5, wherein the guide nozzle protrudes toward an air flow side formed by the combustion air supplied to the inside. Fuel injection device for turbine. 7. The fuel injection device for a gas turbine according to claim 6, wherein the guide nozzle is provided with a nozzle for receiving supply of additional air, and an additional air guide rod provided at a tip end of the nozzle and extending in the air flow direction. And a fuel injection device for a gas turbine.