JPH05264009A - Combustion device - Google Patents

Abstract

PURPOSE:To contrive the reduction of NOx emission at the time of combustion switching action between diffusion and premixed combustions by a method wherein premixed combustion burners are arranged circumferentially and diffusion combustion burners are arranged between the premixed combustion burners. CONSTITUTION:The number of premixed burner openings 33 or diffusion burner openings 34 is determined by the stability of flame and the rate of diffusion combustion. In this example, sixteen premixed combustion burners 33 and eight diffusion combustion burners 34 are both arranged circumferentially and the diffusion combustion burners 34 are spaced apart around the premixed combustion burners 33. By such a ring-shaped structure, even upon intrusion of combustion cylinder cooling air from outside, the mixed gas for the premixed combustion on both the inner and outer circumferential sides are kept warm by the diffusion combustion flame, whereby the fire is spread smoothly and entirely from the diffusion combustion flame to the premixed gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a combustion apparatus used in, for example, a gas turbine, and more particularly, to a diffusion combustion system having a diffusion combustion burner and a premixed combustion burner in one combustion cylinder. The present invention relates to improvement of a combustion device having a double combustion structure of a premixed combustion system.

[0002]

2. Description of the Related Art As a conventional combustion apparatus of this type, a two-stage combustion apparatus has been adopted as disclosed in, for example, Japanese Patent Application Laid-Open No. 61-22127. That is, a diffusion combustion burner is adopted in the first stage arranged in the core of the combustion cylinder, and a premixed combustion burner is adopted in the second stage arranged around it. Combustion is started by the first-stage diffusion combustion burner, and after starting, the combustion is switched to one- or two-stage combustion burner. During normal operation, the proportion of premixed combustion is increased to achieve low temperature combustion due to excess air as a whole. This is done to reduce NOx.

[0003]

In the combustion apparatus thus constructed, it is possible to perform a good operation with a small amount of NOx during the normal operation, but the flame transfer to the premixed combustion is smooth when the combustion burner is switched. I don't like to go, and I dislike the incombustible products. That is, in this type of combustion device, air for cooling the combustion cylinder is usually circulated on the outer peripheral side where the premixed combustion burner is arranged, and this cooling air tends to lower the temperature of the mixed gas. .. Therefore, the flame cannot be smoothly and entirely transferred from the diffusion combustion flame to this low-temperature mixed gas, that is, the sectional load in the combustion chamber is not uniform, and the generation of incombustible products in the low temperature portion and the locally high temperature portion If NOx occurs, NOx
There is a hate that causes

The present invention has been made in view of the above, and even in a two-stage combustion apparatus in which diffusion combustion and premixed combustion are performed, the uniformity of the cross sectional load of the combustion chamber is maintained at the time of combustion switching, and NOx It is an object of the present invention to provide a combustion device of this kind with less generation.

[0005]

That is, according to the present invention, in this type of combustion apparatus having a diffusion combustion burner and a premixed combustion burner in one combustion cylinder, a plurality of the premixed combustion burners are circumferentially annularly formed. In addition, the diffusion combustion burner is arranged between the adjacent premixed combustion burners to achieve the intended purpose.

[0006]

In other words, in the thus constructed combustion device, since the premixed combustion burner is arranged adjacent to the diffusion combustion burner in the circumferential direction, the cooling air for cooling the combustion cylinder even from the outer peripheral side is provided. Even if the gas flows in and out, the mixed gas for premixed combustion is warmed to the flame heat by this diffusion combustion on both the inner and outer sides, so the flame transfer from the diffusion combustion flame to the premixed gas is smooth and general. Therefore, even if the combustion chamber is switched, the combustion chamber is uniformly burned as a whole, and it is possible to obtain this kind of combustion device in which the generation of unburned products and the generation of NOx are reduced.

[0007]

The present invention will be described in detail with reference to the embodiments shown in the drawings. FIG. 1 shows a combustion apparatus 1 of the present invention and its peripheral equipment, that is, a turbine 31 and a compressor 2.

The combustion apparatus 1 mainly includes a liner (combustion cylinder) 27 that forms the combustion chamber 11, an outer cylinder 28 provided around the liner 27, a diffusion combustion burner 34, and a premixed combustion burner 33.
Is formed. The shapes and arrangements of the diffusion combustion burner 34 and the premixed combustion burner 33 will be described later.

Combustion air or cooling air is taken into the compressor 2 from the atmosphere, flows through the diffuser section 4 and is supplied to the air chamber 5. Part of the air in this air chamber is supplied as combustion air for the premixed combustion burner and combustion air 7 for the diffusion combustion burner, and part of the other air is the central supply air 8
Is supplied to the combustion chamber 11 from the central air injection port 10 through the central air intake port 9. Also, part of the combustion air is liner 2
It is used as liner cooling air 26 to cool the 7.

Next, the fuel system will be described. Burner mouth 2
The diffusion gas 14 and the premixing gas 15 are supplied to 4 (the diffusion combustion burner and the entire gas ejection ports of the premixing combustion burner). The diffusion combustion gas 14 is supplied to the diffusion gas chamber 18 and then sent to one or more burner ports.
The premixed combustion gas 15 is supplied to the premixed gas chamber 19 and then sent to the plurality of premixed gas nozzles 20.

After being burned in the combustion chamber 11, these supply gases become a combustion gas flow 12 and are sent to the turbine nozzle section 13. The combustion gas 30 that has exited the slur portion of the turbine expands and works in the turbine portion 31, and is exhausted to the atmosphere as exhaust gas 32. The combustor shown in FIG. 1 shows the outline of the present invention, and FIG. 2 shows a more detailed specific example of the Z portion in the drawing.

In FIG. 2, the upper half shows the cross section of the premixed combustion burner section, and the lower half shows the cross section of the diffusion combustion burner section.

The premixed gas stream 22 injected from the premixed gas nozzle 20 mixes with the premixed air 7 and is supplied as a premixed gas from the burner port 24 to the combustion chamber 11 to produce the premixed flame 2.
It becomes 3.

On the other hand, the gas supplied from the diffusion gas chamber 18 through the diffusion gas throttle hole 38 is sent to the burner port 24 and becomes the diffusion flame 25. The central supply air 8 flows through the ventilation port of the gas supply board 6, flows into the central air cylinder 40 from the central air intake port 9, and the central air injection port 10 and the central air injection port B21.
Is supplied to the combustion chamber 11. In the combustion chamber 11, the axial temperature of the shaft is likely to be locally high due to the liner cooling air, which facilitates the NOx production reaction. In order to prevent this reaction, the central supply air 8 is sent to the combustion chamber 11 through the central air nozzle 10 and the central air nozzle B21. The diffusion gas chamber 18 and the premixed gas chamber 19 are each provided as an annular space in the gas supply board 6. The liner 27 is cooled by the liner cooling air 51.
The cylinder 54 outside the liner is a radiation seal cylinder provided to reduce the heat loss of the combustion device.

FIG. 3 is a view A of FIG. 2, that is, the combustion chamber 11
It is the figure which looked at the burner part more. Burner port 2 shown in FIG.
4 is composed of a premixed combustion burner 33 and a diffusion combustion burner 34. In the figure, the number of premixed combustion burners 33 is 16
Although a specific example of eight diffusion combustion burners is shown for each, the number of premixing burner ports 33 and diffusion burner ports 34 is not particularly limited. This is just one specific example. These numbers should be determined by flame stability and diffusion burn rate. What is important is that the diffusion combustion burner 34 is arranged in the circumferential direction of the premixed combustion burner 33, that is, both are formed in an annular shape.

The premix combustion burner 33 and the diffusion combustion burner 34 include a swirler wall 35, a double swirler outer wall 36 and a double swirler inner wall 37.

The number, direction, and arrangement of the central air nozzles 10 and the central air nozzles B21 of the central air cylinder 40 should be determined by the temperature distribution generated in the combustion chamber 11, and the temperature inside the combustion chamber 11 It is chosen to make the distribution as uniform as possible.

FIG. 4 is a sectional view taken along the line BB of FIG. The premix chamber 41 is shown as having 16 configurations as shown, and the diffusion gas passages 42 are specifically shown as having 8 configurations. The swirler inner wall 17 is provided with a diffusion gas chamber 18, and the diffusion gas is supplied to the diffusion gas passage 42 through the diffusion gas throttle hole 38. Furthermore, a plurality of premixed gas nozzles 2
0 is shown.

FIG. 5 shows the development of a cross section taken along the line CC of FIG. Premixing chamber 41 and diffusion gas passage 42
Is composed of a swirler wall 35, a double swirler outer wall 36 and a double swirler inner wall 37. The premixing chamber 41 and the diffusion gas passage 4 reaching the premixing burner port and the diffusion burner port
2 is bent obliquely as shown in the drawing, and the combustion chamber 1
1 is supplied as a swirling flow. The premixed gas flow 22 ejected from the premixed gas nozzle 20 is mixed with the premixed air 7 in the premixing chamber 41 and is supplied into the combustion chamber 11 through the premixing burner port. On the other hand, the diffusion gas flowing out from the diffusion gas throttle hole 38 passes through the diffusion gas passage 42,
It is supplied into the combustion chamber 11 from the diffusion burner port.

FIG. 6 shows details of the E portion of FIG. At the tips of the swirler wall 35 and the double swirler inner wall 37, a protrusion 43 as shown is provided. This is for stabilizing the flame due to the vortex that a part of the premixed gas flow 22 causes in the wake of the protrusion. It also has the function of a frame holder.

FIG. 7 shows the details of the view from F in FIG. In a gas turbine combustor, for example,
Since the combustor inlet air temperature is about 300 to 360 ° C., the combustion temperature is relatively high, and a high load combustion state is achieved,
It is necessary to consider cooling of the protrusion 43. Therefore, in this embodiment, one or a plurality of cooling slits 39 are provided as shown in the drawing, and a part of the premixed gas flow 22 is flown between the cooling slits 39 to cool the protrusions 43. .. Therefore, it is important that the width of the cooling slit 39 is narrow so that no combustion reaction occurs inside. By reducing the pitch of the cooling slits 39, the side surface area of the cooling slits is increased, so that the cooling efficiency is improved. The action of the cooling slit 39 is that the temperature boundary layer generated on the ventral side of the swirler wall 35 can be sucked to increase the heat transfer coefficient on the ventral side, and further from the combustion surface, in the wake of the protrusion 43. That contributes to the stability improvement of the flame by subdividing the generated vortex.
It is extremely effective in that it can prevent the generation of thermal stress due to thermal expansion. The projection 43 not only stabilizes the combustion of the premixed gas but also stabilizes the flame of the diffusion gas supplied from the diffusion burner port, so that when the diffusion combustion is switched to the premixed combustion. Also serves as a frame holder.

FIG. 8 shows a G view of FIG. The protrusion 43 is similar to the view of FIG. 7F, but a diffusion gas passage 42 constituted by a double swirler outer wall 36 and a double straw inner wall 37 is provided. Therefore, the swirl wall 35
Cooling of the dorsal side of the is carried out by the premixed gas stream 22;
The back wall of the inner wall of the heavy swirler is cooled with diffusion gas. Further, the outer wall 36 of the double swirler is cooled by the diffusion gas on the ventral side and the premixed gas flow 22 on the back side. Therefore, the cooling effect of the protrusion 43 may vary depending on the case. In this case, it can be dealt with by changing the number of the cooling slits.

FIG. 9 shows another embodiment according to the present invention of a developed sectional view taken along the line CC of FIG. As shown in FIG. 5, the Venturi type premix chamber 44 is shown in FIG.
Is different from This is important for making the premixed gas flow 22 supplied to the premixing burner port 33 as uniform as possible and making the temperature of the combustion gas uniform so as to reduce NOx. The Venturi-type premixing chamber 44 is characterized by high mixing efficiency and small pressure loss, and is extremely suitable for premixed combustion in a gas turbine combustor.

In the above description, the case of forming the premix combustion burner and the diffusion combustion burner annularly in the circumferential direction has been described, but this is not always the case. It may be possible to form a plurality of stages concentrically with the combustion cylinder.

The combustion device having the structure described above has the following effects. That is, first of all, since the premixed combustion burner is arranged adjacent to the diffusion combustion burner in the circumferential direction, even if the cooling air for cooling the combustion cylinder enters and flows from the outer peripheral side, the premixed combustion burner is premixed. Since the mixed gas for combustion is warmed to flame heat by this diffusion combustion on both the inner and outer sides, the transition from the diffusion combustion flame to the premixed gas is performed smoothly and generally, and therefore even when switching. It is possible to obtain this kind of combustion device in which the combustion chamber is uniformly burned in its entirety and the generation of unburned products and the generation of NOx are small. Therefore, from the combustion of the gas turbine to the rated load, diffusion combustion with a wide combustion width It is possible to change continuously until premixed combustion suitable for low NOx combustion. As a result, exhaust gas characteristics such as NOx, CO and unburned hydrocarbons can be greatly improved. Secondly, by making the burner port 24 multi-staged, so-called multi-stage combustion can be performed to achieve low NOx combustion. Therefore, ideal low pollution combustion can be achieved.

Thirdly, by providing the projections 43 at the tips of the premixing burner port and the diffusion burner port, the stable combustion width can be expanded, and a further lean premixed gas can be burned, so that a large amount of NOx can be obtained. A reduction can be achieved.

Fourthly, by providing one or a plurality of cooling slits in the protrusion 43, it is possible to lower the temperature of the protrusion 43 and at the same time improve the stability of the flame and prevent the occurrence of thermal stress. Therefore, it is possible to provide a highly reliable and long-life combustor.

The fifth effect is that by supplying a part of the combustion air from the central air injection port 10 and the central air injection port B21 to the high temperature portion (NOx production reaction is promoted) generated in the axial center portion of the combustion chamber 11, local Low NO because it can prevent the generation of high temperature parts
x combustion can be effectively performed. A sixth advantage of the present invention is that the premix chamber is a venturi type premix chamber 4.
By setting the number to 4, a more uniform premixed gas can be obtained, and thus, low NOx combustion close to ideal can be performed.

[0029]

As described above, according to the present invention, a plurality of premixed combustion burners are arranged annularly in the circumferential direction, and a diffusion combustion burner is arranged between adjacent premixed combustion burners. Therefore, since the premixed combustion burner is arranged adjacent to the diffusion combustion burner in the circumferential direction,
Even if the cooling air for cooling the combustion cylinder enters and flows from the outer peripheral side, the mixed gas for premixed combustion is warmed to the flame heat by this diffusion combustion on both inner and outer peripheral sides. The transition to the premixed gas is carried out smoothly and generally, and therefore even in the case of switching, the combustion chamber has a uniform combustion as a whole, so that the generation of unburned products and the generation of NOx are reduced. Can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of a combustion apparatus of the present invention.

FIG. 2 is an enlarged sectional view of a Z part in FIG.

3 is a view A of the burner as viewed from the inside of the combustion chamber in FIG.

4 is a cross-sectional view taken along the line BB of FIG.

5 is a sectional development view taken along the line CC of FIG.

FIG. 6 is a detailed view of an E portion of FIG.

FIG. 7 is an F view of FIG.

8 is a cross-sectional view taken along the line BB of FIG.

FIG. 9 is a sectional development view showing another modified example taken along the line CC of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Combustion device, 2 ... Compressor, 3 ... Compressed air, 4 ... Diffuser part, 5 ... Air chamber, 6 ... Gas supply board, 7 ... Premixed air, 8 ... Central supply air, 9 ... Central air intake Inlet, 10 ... Central air jet, 11 ... Combustion chamber, 12 ... Combustion gas flow, 13 ...
Turbine nozzle part, 14 ... Diffusion gas, 15 ... Premixing gas, 16 ... Swirler outer wall, 17 ... Swirler inner wall, 18 ... Diffusion gas chamber, 19 ... Premixed gas chamber, 20 ... Premixed gas nozzle, 21 ... Central air Nozzle B, 22 ... Premixed gas flow, 2
3 ... Premixed flame, 24 ... Burner mouth, 25 ... Diffusion flame, 2
6 ... Liner cooling air, 27 ... Liner, 28 ... Outer cylinder, 29
... head plate, 30 ... combustion gas, 31 ... turbine part, 32 ...
Exhaust gas, 33 ... Premix combustion burner, 34 ... Diffusion combustion burner, 35 ... Swirler wall, 36 ... Double swirler outer wall, 37 ... 2
Heavy swirler inner wall, 38 ... Diffusion gas throttle hole, 39 ... Cooling slit, 40 ... Central air cylinder, 41 ... Premix chamber, 42 ... Diffusion gas passage, 43 ... Projection part, 44 ... Venturi type premix chamber.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Ichiman Iwai, 502 Jinritsucho, Tsuchiura-shi, Ibaraki Machinery Research Laboratory, Hiritsu Manufacturing Co., Ltd. (72) Tadataka Murakami 4026, Kuji-cho, Hitachi, Ibaraki Hitsuritsu Inside Hitachi Research Laboratory

Claims (11)

[Claims] 1. A combustion apparatus comprising a plurality of premixed combustion burners and a diffusion combustion burner in a combustion cylinder, wherein the plurality of premixed combustion burners are annularly arranged in a circumferential direction and are adjacent to each other. A combustion apparatus characterized in that the diffusion combustion burner is arranged between premixed combustion burners. 2. A combustion apparatus having a diffusion combustion burner and a premixed combustion burner in a combustion cylinder, wherein the diffusion combustion burner and the premixed combustion burner are alternately arranged in the circumferential direction. And a combustion device. 3. A combustion apparatus having a diffusion combustion burner and a premixed combustion burner in a combustion cylinder, wherein a plurality of the premixed combustion burners are circumferentially arranged annularly and the diffusion combustion burner is provided with the premixed combustion burner. A combustion device characterized in that a plurality of mixed combustion burners are arranged at every other place. 4. A combustion apparatus comprising a diffusion combustion burner and a premixed combustion burner in a combustion cylinder, wherein a plurality of the diffusion combustion burners are arranged in an annular shape in the circumferential direction, and between the adjacent diffusion combustion burners. A combustion apparatus characterized in that the premixed combustion burner is arranged in the. 5. A combustion apparatus comprising a plurality of diffusion combustion burners and a plurality of premix combustion burners in a combustion cylinder, wherein the diffusion combustion burners and the premix combustion burners are mixedly arranged in an annular shape. Combustion device characterized in that 6. A combustion apparatus comprising a diffusion combustion burner and a premixed combustion burner in a combustion cylinder, wherein a plurality of the premixed combustion burners are arranged side by side in the circumferential direction and a plurality of adjacent premixed combustion burners are arranged. A combustion apparatus, wherein at least one diffusion combustion burner is arranged between the burners. 7. A combustion apparatus comprising a diffusion combustion burner and a premixed combustion burner in a combustion cylinder, wherein the diffusion combustion burner and the premixed combustion burner are alternately arranged in the circumferential direction, and the diffusion combustion burner is arranged. And a premixed combustion burner, each of which is provided with a supply fuel control device for controlling a supply fuel. 8. A combustion apparatus having a diffusion combustion burner and a premixed combustion burner in a combustion cylinder, wherein an air cylinder for supplying cooling air into the combustion cylinder is provided at an upstream axial center portion of the combustion cylinder. , And a plurality of the premixing burners are arranged side by side around the outside of the air cylinder, and between the premixing combustion burners adjacent to each other,
A combustion apparatus, wherein the diffusion combustion burner is arranged. 9. A combustion cylinder forming a combustion chamber, a diffusion combustion burner arranged in the upstream side of the combustion cylinder and operating in the full load band, and arranged in the upstream side of the combustion cylinder. In a combustion device provided with a premixed combustion burner operated in a high load zone, an air cylinder for supplying cooling air to the inside of the combustion cylinder is provided at an upstream side axial portion of the combustion cylinder, and Combustion characterized in that a plurality of the premixed combustion burners are arranged side by side on the outer periphery, and the diffusion combustion burners are arranged between adjacent premixed combustion burners having a plurality of the premixed combustion burners. apparatus. 10. The combustion apparatus according to claim 9, wherein the vicinity of the combustion gas ejection ports of the premixed combustion burner and the diffusion combustion burner is bent in the circumferential direction to impart rotation to the combustion gas. 11. The combustion apparatus according to claim 10, wherein slits extending in a flow direction of the combustion gas are provided on the side walls of the combustion gas outlet of the premixed combustion burner and the diffusion combustion burner.