JPH07318059A - Gas turbine burner - Google Patents

Abstract

PURPOSE:To allow a blow-off to scarcely occur and to eliminate the generation of NOx by enhancing reliability with a simple structure and stably burning from the start to the maximum load. CONSTITUTION:The gas turbine burner comprises a combustion chamber 11, a fuel injection tube 14 provided axially movably between an insertion position A and a drawing position B and having a primary injection hole 12 at its end and a secondary injection hole 13 at the outer periphery of the intermediate part, a ring 15 partly surrounding the tube to close the secondary hole at the inserting position, an inside duct 16 surrounding the tube via an interval, and an outside duct 17 surrounding the duct at an interval. The secondary hole is closed by the ring at the position A, fuel is injected from the primary hole to form a diffused flame 7 in the chamber, the fuel is injected in the inside duct from the primary hole at the position B to premix the fuel in the inside duct to form a primary premixing flame 8, the fuel is injected from the secondary hole between the inside duct and the outside duct to premix the fuel to form a secondary premixing flame.

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, and more particularly to a low NOx combustor capable of performing stable combustion from start to maximum load and generating less NOx.

[0002]

2. Description of the Related Art A gas turbine combustor is housed in a casing 1, which is generally hollow cylindrical, as illustrated in FIG.
The air 2 compressed by the compressor C of the gas turbine is introduced into the casing 1, and the combustion exhaust gas 3 burned by the gas turbine combustor is guided to the turbine T of the gas turbine to take out external power such as power generation and driving. It is like this. Such a gas turbine combustor can continuously burn a gas fuel or a liquid fuel, but since it burns at a high temperature, it is apt to generate NOx and has a large thermal deformation.

Many studies have been conducted on such a gas turbine combustor in order to suppress the generation of NOx, which is an air pollutant, and are disclosed in Japanese Patent Publication No. 4-80292 and Japanese Patent Publication No. 61-52523. Kaihei 5-296412
No. Gazette, etc. have already been filed. Tokkyo 4-80
The No. 292 "gas turbine combustor" divides the combustion region into two parts, primary and secondary, and both are burned in premixed combustion to achieve low N
The "gas turbine combustor" of Japanese Patent Laid-Open No. 61-52523 changes the air flow rate for combustion by a variable device of the air passage area to obtain an optimum air ratio and a low N ratio.
The "combustion device and the combustion method" of Japanese Patent Laid-Open No. 5-296412 discloses that the fuel supply system is divided into three to obtain an appropriate air-fuel ratio to reduce the NOx.

[0004]

However, in the conventional gas turbine combustor, the stable operation range is narrow, and if the fuel flow rate is reduced at the time of starting or low load, stable combustion cannot be performed and the flame may blow out. There was a point. That is, Japanese Patent Publication No. 4-80292, “Gas turbine combustor”
However, in order to always burn with premixed combustion, it is necessary to install a diffusion combustion type pilot burner separately in order to stabilize the flame at low output. This pilot burner easily generates NOx and the fuel system has three systems. It is necessary and there is a problem that the control of opening and closing is complicated.

Further, in the "gas turbine combustor" of Japanese Patent Application Laid-Open No. 61-52523, a "variable mechanism of air flow rate" which is unnecessary in a normal gas turbine combustor is indispensable for reducing NOx, and this variable mechanism is required. Since it is formed in the combustion chamber, failure due to thermal deformation or the like is likely to occur, and the structure is complicated and reliability is poor. Furthermore, JP-A-5-29641
No. 2 “Combustion device and combustion method” requires three fuel supply systems, and there is a problem that the control of opening and closing thereof is complicated.

The present invention was devised to solve the above-mentioned various problems. That is, the object of the present invention is a structure is simple and highly reliable, stable combustion is possible from the start to the maximum load, blowout hardly occurs, and
An object is to provide a gas turbine combustor that generates less NOx.

[0007]

According to the present invention, a combustion chamber in which fuel is burned inside is provided movably in the axial direction between an insertion position and a withdrawal position, and a primary injection hole is provided at the tip. A fuel injection pipe having a secondary injection hole on the outer periphery of the intermediate portion, and a ring that partially surrounds the fuel injection pipe and closes the secondary injection hole at the insertion position,
A hollow cylindrical inner duct that encloses the fuel injection pipe at a distance and has one end open to the combustion chamber and introduces air from the other end, and an inner duct that surrounds the inner duct at a distance and has one end open to the combustion chamber and air from the other end. An outer duct for introducing the fuel injection pipe, and at the insertion position of the fuel injection pipe, the secondary injection hole is closed with a ring to inject fuel from the primary injection hole to form a diffusion flame in the combustion chamber. At the extraction position, the fuel is injected from the primary injection hole into the inner duct to premix the fuel and air in the inner duct to form the primary premixed flame in the combustion chamber, and the inner duct from the secondary injection hole. There is provided a gas turbine combustor, characterized in that fuel is injected between the outer duct and the outer duct and the fuel and air are premixed therebetween to form a secondary premixed flame in the combustion chamber.

According to a preferred embodiment of the present invention, a primary swirler for connecting the ring and the inner duct to swirl air introduced into the inner duct, and connecting the inner duct and the outer duct with each other between them. 2 to swirl the air
The next swirler is further provided.

[0009]

According to the structure of the present invention described above, the fuel injection pipe having the primary injection hole at the tip and the secondary injection hole at the outer periphery of the intermediate portion is movable in the axial direction between the insertion position and the withdrawal position. And a ring partially surrounds the fuel injection pipe and
Since the secondary injection hole is closed, the secondary injection hole is closed by the ring with the fuel injection pipe at the insertion position, and the fuel is injected only from the primary injection hole to form the diffusion flame in the combustion chamber. Diffusive combustion that is hard to blow out can be performed.
Further, the fuel injection pipe is moved to the extraction position, the fuel is injected from the primary injection hole into the inner duct, and the fuel and air are premixed in the inner duct to form the primary premixed flame in the combustion chamber. In addition, the fuel is injected between the inner duct and the outer duct from the secondary injection hole, and the fuel and air are premixed between them to form the secondary premixed flame in the combustion chamber, thereby premixing at a certain output or more. By switching to combustion, it is possible to suppress the generation of NOx at high output.

Further, if a primary swirler is provided between the ring and the inner duct and a secondary swirler is provided between the inner duct and the outer duct, the premixing of fuel and air can be performed more effectively.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, common parts are designated by the same reference numerals and used. 1 and 2 are overall configuration diagrams of a gas turbine combustor according to the present invention.
FIG. 2 shows a state from start to low output, and FIG. 2 shows a state at high output. The gas turbine combustor 10 of the present invention is housed in a hollow cylindrical casing 1, and air 2 compressed by a compressor (not shown) of the gas turbine is introduced into the casing 1. . Further, the combustion exhaust gas 3 burned by the gas turbine combustor is guided to a turbine (not shown) of the gas turbine to take out external power. Such a configuration is similar to that of a conventional gas turbine. The fuel burned in the gas turbine is preferably gas fuel, but may be liquid fuel.

Referring to FIGS. 1 and 2, a gas turbine combustor 10 of the present invention has a combustion chamber 11 in which fuel is burned.
Is provided so as to be movable in the axial direction between the insertion position A and the withdrawal position B, has a primary injection hole 12 at the tip, and 2 at the outer periphery of the intermediate portion.
Fuel injection pipe 14 having secondary injection hole 13, and fuel injection pipe 14
The fuel injection pipe 14 and the ring 15 that partially surrounds the fuel injection pipe 14 and closes the secondary injection hole 13 at the insertion position A.
A hollow cylindrical inner duct 16 which is open at one end 16a and which introduces air 2 from the other end 16b, and which surrounds the inner duct 16 with a space, and one end 17a is opened at the combustion chamber 11 and the other end 17
and an outer duct 17 for introducing air 2 from b.

Further, the gas turbine combustor 10 of the present invention.
Is a primary swirler 18 that connects the ring 15 and the inner duct 16 and swirls the air 2 introduced into the inner duct 16.
And a secondary swirler 19 that connects the inner duct 16 and the outer duct 17 and swirls the air 2 introduced therebetween.

The fuel injection pipe 14 penetrates a lid 4 provided at one end of the casing 1, and a gasket 5 is provided in the penetrating portion.
Is provided to hold the through portion airtightly. The fuel injection pipe 14 may be a single pipe for supplying the same fuel to the primary injection hole 12 and the secondary injection hole 13, or may be a double pipe for supplying different fuel. In addition, this fuel injection pipe 1
4 can be moved in the axial direction between the insertion position A and the withdrawal position B manually or by an appropriate driving device (a direct acting cylinder, an electromagnetic solenoid, etc.).

As shown in FIG. 1, 1 at the insertion position A
The secondary injection hole 12 is located near the end surface of the combustion chamber 11. Further, at the insertion position A, the secondary injection hole 13 is closed by the ring 15. The fitting between the fuel injection pipe 14 and the ring 15 does not have to be completely airtight as long as the fuel leaks slightly from the secondary injection hole 13 at the insertion position A.

Further, as shown in FIG. 2, at the withdrawal position B, the primary injection hole 12 is located near the primary swirler 18,
The swirling flow of air formed by the primary swirler 18 can effectively premix the fuel and air injected from the primary injection holes 12. Further, at the extraction position B, the secondary injection hole 13 is located outside the other end 16b of the inner duct 16 so that fuel can be injected between the inner duct 16 and the outer duct 17.

With this structure, as shown in FIG. 1, the fuel injection pipe 14 is set to the insertion position A, the secondary injection hole 13 is closed by the ring 15, and the fuel 6 is injected only from the primary injection hole 12 to burn the combustion chamber. By forming the diffusion flame 7 in 11, it is possible to perform diffusion combustion that is difficult to blow out from the start to the low output. Also, by moving the fuel injection pipe 14 to the withdrawal position B,
The fuel 6 is injected from the primary injection hole 12 into the inner duct 16 to premix the fuel and air in the inner duct 16 to form the primary premixed flame 8 in the combustion chamber, and from the secondary injection hole 13 By injecting the fuel 6 between the inner duct 16 and the outer duct 17 and premixing the fuel and air between them to form the secondary premixed flame 9 in the combustion chamber, the premixed combustion is switched to above a certain output. It is possible to suppress the generation of NOx at the time of high output.

FIG. 3 is a diagram showing the relationship between the engine operating conditions and the equivalence ratio in the combustion region. In this figure, the horizontal axis represents the engine load state, and the vertical axis represents the equivalence ratio in the combustion region. Further, equivalence ratio = fuel theoretical air-fuel ratio / actual air-fuel ratio, and air-fuel ratio = air weight / fuel weight. Further, in FIG. 3, the horizontal upper solid line is the upper limit of the equivalence ratio determined by the NOx regulation value, the horizontal broken line is the lean side blowout limit equivalence ratio of premixing, and the horizontal lower solid line is This is the limit equivalent ratio of the diffusion of the diffusion flame.

The gas turbine combustor 10 of the present invention is operated in the state shown in FIG. 1 in the low output range from starting to around 50% load. That is, the fuel injection pipe 14 is set to the insertion position A, and the primary injection hole 12 is projected to the end surface of the combustion chamber.
The next swirler 18 prevents the premixing and burns it as the diffusion flame 7, so that the acceleration can be stably performed. At this time, the secondary injection hole 13 is closed by the ring 15, and no fuel is left. The equivalent ratio (proportional to NOx amount) during this period is
As shown in FIG. 3, the fuel increases abruptly during acceleration, but it is at a position sufficiently lower than the upper limit of NOx.
When the rated rotational speed of the gas turbine is reached at the position where the load is 0 and then the equivalence ratio (proportional to the NOx amount) also increases as the load is sequentially increased, and when combustion is continued to the high output in the state of FIG. 1, the solid line in FIG. As shown, the upper limit equivalence ratio of NOx is exceeded at 60 to 70% load. The gas turbine combustor 10 of the present invention is switched to the state shown in FIG. 2 as indicated by a dashed arrow in the figure near 50% load. That is, the fuel injection pipe 14 is moved to the withdrawal position B, the primary injection hole 12 is positioned near the outlet of the primary swirler 18, and the secondary injection hole 13 is located at the inlet upstream position of the secondary swirler 19. To do. As a result, fuel is separately supplied to the primary premixing chamber (inside the inner duct 16) and the secondary premixing chamber (between the inner duct 16 and the outer duct 17), and low NO due to premixed combustion.
x can be achieved.

The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0021]

As described above, the gas turbine combustor of the present invention has a simple structure, high reliability, simple fuel control, and since the moving part is cooled by the fuel, there is little deformation, and it is easy to start. Stable combustion is possible up to the maximum load, blowout is less likely to occur, and NOx is less generated.
And so on.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a gas turbine combustor according to the present invention from start to low output.

FIG. 2 is an overall configuration diagram of a gas turbine combustor according to the present invention at high output.

FIG. 3 is a diagram showing a relationship between an engine operating condition and an equivalence ratio in a combustion region.

FIG. 4 is a configuration diagram of a conventional gas turbine combustor.

[Explanation of symbols]

 1 Casing 2 Air 3 Combustion exhaust gas 4 Lid 5 Gasket 6 Fuel 7 Diffusion flame 8 Primary premixed flame 9 Secondary premixed flame 10 Gas turbine combustor 11 Combustion chamber 12 Primary injection hole 13 Secondary injection hole 14 Fuel injection pipe 15 ring 16 inner duct 17 outer duct 18 primary swirler 19 secondary swirler A insertion position B extraction position

Claims (2)

[Claims] 1. A combustion chamber in which fuel is combusted inside, and an insertion position and an extraction position are provided so as to be axially movable.
A fuel injection pipe having a primary injection hole at the tip and a secondary injection hole at the outer periphery of the middle portion, a ring that partially surrounds the fuel injection pipe and closes the secondary injection hole at the insertion position, and the fuel injection pipe are spaced from each other. A hollow cylindrical inner duct which is surrounded by a space and has one end opened to the combustion chamber to introduce air from the other end; and an outer duct which surrounds the inner duct at a space and has one end opened to the combustion chamber and introducing air from the other end. ,
At the insertion position of the fuel injection pipe, the secondary injection hole is closed with a ring, fuel is injected from the primary injection hole to form a diffusion flame in the combustion chamber, and the primary injection is made at the extraction position of the fuel injection pipe. Fuel is injected into the inner duct through the holes to premix the fuel and air in the inner duct to form a primary premixed flame in the combustion chamber, and the fuel is injected between the inner duct and the outer duct through the secondary injection holes. Is injected and the fuel and air are premixed between them to form a secondary premixed flame in the combustion chamber. 2. A primary swirler that connects the ring and the inner duct and swirls the air introduced into the inner duct.
The gas turbine combustor according to claim 1, further comprising a secondary swirler that connects the inner duct and the outer duct and swirls air introduced therebetween.