CN114992671B - Combined gas turbine combustion chamber - Google Patents

Abstract

A combined gas turbine combustion chamber belongs to the technical field of gas turbine combustion chambers. The combustion device is arranged in the outer shell, an air inlet cavity is formed between the outer wall of the combustion device and the inner wall of the outer shell, and an air inlet is formed in the outer shell; the combustion device comprises a burner and a flame tube, a nozzle tube bundle area communicated with the air inlet cavity is arranged on the burner, the flame tube is arranged at the periphery of the nozzle tube bundle area, and a flue gas outlet communicated with the flame tube is arranged on the outer shell; the periphery of the nozzle tube bundle area is provided with an air distribution cavity wrapping the nozzle tube bundle area, the air distribution cavity is communicated with the air inlet cavity, the front part of the nozzle tube bundle, which is close to the fuel supply area, is a premixing section, the rear part of the nozzle tube bundle, which is close to the flame tube, is a shunting section, the shunting section comprises a middle main flow area and an annular flame stabilizing area arranged at the periphery of the main flow area, and the main flow area and the flame stabilizing area are both communicated with the premixing section; the end of the premixing section is provided with a fuel inlet communicated with the fuel supply area, and the peripheral wall of the premixing section is provided with an air inlet communicated with the air distribution cavity.

Description

A combined gas turbine combustion chamber

Technical Field

The invention relates to the technical field of gas turbine combustion chambers, in particular to a combined gas turbine combustion chamber.

Background technique

Gas turbines have become an indispensable source of power in industrial production due to their high efficiency and cleanliness. With the iteration and update of technology, gas turbines are constantly developing towards higher efficiency and wider load regulation range. How to achieve stable, low-emission combustion within a wide load range is an important performance target of the gas turbine combustor.

Most of the existing gas turbines use burners with Dry Low NOx (DLN) combustion technology. Such burners mainly mix excess air and fuel into lean premixed gas to suppress the generation of nitrogen oxides. However, when the gas turbine develops to J level, its temperature level is close to the critical value of the DLN effective working range (1670-1900K). If the temperature rises further, on the one hand, even if the air and fuel are fully premixed, nitrogen oxide emissions will increase significantly. On the other hand, if conventional swirl premixed combustion is used, there are risks such as flashback, self-ignition, and thermoacoustic oscillation. Therefore, Dry Low NOx (DLN) combustion technology can no longer meet the development of gas turbines.

Compared with traditional swirl burners, micro-premixed combustion technology mixes air and fuel in a tiny pipe, which improves the uniformity of gas mixing, has a small flame structure, and a high gas flow rate. In addition, due to the quenching effect of the pipe diameter, micro-premixed combustion technology can not only reduce NOX emissions but also has good anti-flashback capabilities.

Summary of the invention

The technical problem to be solved by the present invention is to provide a combined gas turbine combustion chamber which can improve the uniformity of gas mixing, has a small flame structure and a high gas flow rate in view of the deficiencies in the prior art.

The technical problem to be solved by the present invention is achieved by the following technical solution. The present invention is a combined gas turbine combustion chamber, characterized in that: it comprises an outer shell, a combustion device is installed in the outer shell, an air intake cavity is formed between the outer wall of the combustion device and the inner wall of the outer shell, and an air intake port communicating with the air intake cavity is provided on the outer shell;

The combustion device comprises a burner and a flame tube, the burner is provided with a nozzle tube bundle area, a nozzle tube bundle is installed in the nozzle tube bundle area, the nozzle tube bundle comprises a duty class nozzle tube bundle arranged in the middle of the burner and a main combustion class nozzle tube bundle arranged on the periphery of the duty class nozzle tube bundle, the flame tube is provided with an upper opening and a lower opening, the upper opening of the flame tube is arranged on the periphery of the nozzle tube bundle area, and the outer shell is provided with a smoke outlet communicated with the lower opening of the flame tube;

The burner is provided with a fuel supply area in the direction facing the nozzle tube bundle area, and the fuel supply area includes a duty class fuel cavity that supplies fuel to the duty class nozzle tube bundle and a main combustion stage fuel cavity that supplies fuel to the main combustion stage nozzle tube bundle;

An air distribution cavity wrapping the nozzle tube bundle area is arranged on the periphery of the nozzle tube bundle area, and the air distribution cavity is communicated with the air intake cavity. The front part of the nozzle tube bundle close to the fuel supply area is a premixing section, and the rear part close to the flame tube is a diversion section. The diversion section includes an intermediate mainstream area and an annular flame stabilizing area arranged on the periphery of the mainstream area. Both the mainstream area and the flame stabilizing area are communicated with the premixing section. A swirl blade is installed at the connection between the flame stabilizing area and the premixing section. The axial angle of the swirl blade is 5~30°. A fuel inlet communicated with the fuel supply area is arranged at the end of the premixing section, and an air inlet hole communicated with the air distribution cavity is arranged on the outer peripheral wall of the premixing section.

The technical problem to be solved by the present invention can be further achieved by the following technical solution: the inner diameter of the main combustion stage nozzle bundle and the duty stage nozzle bundle is 5 to 12 mm, and the length is 15 to 120 mm.

The technical problem to be solved by the present invention can be further achieved through the following technical scheme: a duty class fuel pipe is installed in the duty class fuel cavity, and a main combustion class fuel pipe is installed in the main combustion class fuel cavity.

The technical problem to be solved by the present invention can be further achieved through the following technical scheme, wherein the flame tube forms a duty class combustion zone in the area connected with the duty class nozzle bundle area, and forms a main combustion class combustion zone in the area connected with the main combustion class nozzle bundle area.

The technical problem to be solved by the present invention can be further achieved by the following technical solution: the air inlet is arranged on the outer shell near the smoke outlet end.

The technical problem to be solved by the present invention can be further achieved by the following technical solution: the duty class fuel pipe is provided with one, and the main combustion class fuel pipe is provided with at least two.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The nozzle micro-premixing tube bundle is equipped with a mainstream zone and a flame stabilization zone at the downstream outlet. The mainstream zone does not change the original airflow state, while the flame stabilization zone has an expansion structure. The mixed airflow decelerates and expands, which is beneficial to both flame stability and the formation of downstream swirl structure. In addition, the large velocity gradient of the airflow in the mainstream zone and the flame stabilization zone is also beneficial to energy transfer between airflows, thereby improving flame stability.

(2) Swirl blades are set at the entrance of the flame stabilization zone, so that a swirl zone can be formed around the jet in the mainstream zone. On the one hand, it strengthens the energy transfer of the airflow between the mainstream zone and the flame stabilization zone. On the other hand, it can serve as a stable ignition source for the main airflow, improve combustion stability, and broaden the operating boundary of the combustion chamber.

(3) Compared with traditional burners, the nozzle bundles of the main nozzle of this burner are relatively independent and can be expanded in a modular array according to load requirements, so it has better scalability; and the nozzle bundles are all set at the millimeter level. By mixing the fuel and air at the millimeter scale, a more uniform fuel and air premix can be obtained compared to traditional swirl premixed burners, which can reduce the peak flame temperature during the combustion process, thereby achieving a better nitrogen oxide emission reduction effect.

(4) Since the flame formed by the micro-mixing tube is relatively short and the temperature distribution is uniform, the length of the flame tube in the combustion chamber can be greatly shortened.

(5) Since multiple micro-premixing tubes are distributed in an array, the ejected flames are relatively dispersed in the radial direction and the heat release is relatively uniform. At the same time, each main nozzle micro-mixing tube can adopt different structural schemes to achieve natural frequency differences, reduce the probability of thermal-acoustic coupling, and effectively avoid combustion instability problems.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic diagram of the combustion chamber structure principle;

FIG2 is a schematic diagram of the three-dimensional structure of the combustion chamber;

Fig. 3 is a schematic cross-sectional view of a burner;

FIG4 is a top view of the burner body;

Figure 5 is a schematic diagram of the nozzle tube bundle structure;

In the figure: 1. combustion device; 2. outer shell; 3. flame tube; 4. burner; 21. air inlet; 22. air flow direction; 23. air inlet cavity; 31. duty class combustion zone; 32. main combustion stage combustion zone; 41. main combustion stage fuel pipe; 41A. main combustion stage fuel inlet; 42. duty class fuel pipe; 42A. duty class fuel inlet; 43. main combustion stage fuel bin; 44. duty class fuel bin; 45. main combustion stage nozzle bundle; 45A. air inlet; 45B. nozzle bundle fuel inlet; 45C. swirl blade; 45D. diverter; 45E. mainstream zone; 45F. flame stabilization zone; 46. duty class nozzle bundle; 47. fuel bin and air baffle; 48. burner body end cover; 49. fuel flow direction; 410. mixture flow direction.

Detailed ways

The specific technical solutions of the present invention are further described below to help those skilled in the art further understand the present invention, but do not constitute a limitation on the rights thereof.

1 to 5, a combined gas turbine combustion chamber comprises an outer shell, a combustion device is installed in the outer shell, an air intake cavity is formed between the outer wall of the combustion device and the inner wall of the outer shell, and an air intake port communicating with the air intake cavity is provided on the outer shell;

The combustion device comprises a burner and a flame tube, the burner is provided with a nozzle tube bundle area, a nozzle tube bundle is installed in the nozzle tube bundle area, the nozzle tube bundle comprises a duty class nozzle tube bundle arranged in the middle of the burner and a main combustion class nozzle tube bundle arranged on the periphery of the duty class nozzle tube bundle, the flame tube is provided with an upper opening and a lower opening, the upper opening of the flame tube is arranged on the periphery of the nozzle tube bundle area, and the outer shell is provided with a smoke outlet communicated with the lower opening of the flame tube;

The burner is provided with a fuel supply area in the direction facing the nozzle tube bundle area, and the fuel supply area includes a duty class fuel cavity that supplies fuel to the duty class nozzle tube bundle and a main combustion stage fuel cavity that supplies fuel to the main combustion stage nozzle tube bundle;

An air distribution cavity wrapping the nozzle tube bundle area is arranged on the periphery of the nozzle tube bundle area, and the air distribution cavity is communicated with the air intake cavity. The front part of the nozzle tube bundle close to the fuel supply area is a premixing section, and the rear part close to the flame tube is a diversion section. The diversion section includes an intermediate mainstream area and an annular flame stabilizing area arranged on the periphery of the mainstream area. Both the mainstream area and the flame stabilizing area are communicated with the premixing section. A swirl blade is installed at the connection between the flame stabilizing area and the premixing section. The axial angle of the swirl blade is 5~30°. A fuel inlet communicated with the fuel supply area is arranged at the end of the premixing section, and an air inlet hole communicated with the air distribution cavity is arranged on the outer peripheral wall of the premixing section.

The inner diameter of the main combustion stage nozzle bundle and the duty stage nozzle bundle is 5 to 12 mm, and the length is 15 to 120 mm. The nozzle bundles are all set at the millimeter level. By mixing the fuel and air at the millimeter scale, a more uniform fuel and air premix can be obtained compared to the traditional swirl premixed burner, which can reduce the peak flame temperature during the combustion process, thereby achieving a better nitrogen oxide emission reduction effect.

A duty class fuel pipe is installed in the duty class fuel cavity, and a main combustion class fuel pipe is installed in the main combustion class fuel cavity.

The cross-sectional area of the rear end of the nozzle tube bundle is larger than that of the front end, and the flame stabilization zone presents an expansion structure. The mixed airflow decelerates and expands, which is beneficial to both flame stability and the formation of a downstream swirl structure. In addition, the large velocity gradient of the airflow in the mainstream zone and the flame stabilization zone is also beneficial to energy transfer between airflows, thereby improving flame stability.

A swirl blade is also installed at the entrance of the flame stabilization zone, which can form a swirl zone around the jet in the mainstream zone. On the one hand, it strengthens the energy transfer of the airflow in the mainstream zone and the flame stabilization zone, and on the other hand, it can serve as a stable ignition source for the main airflow, thereby improving the combustion stability and broadening the operating boundary of the combustion chamber.

The flame tube forms a duty class combustion zone in the area connected with the duty class nozzle bundle area, and forms a main combustion stage combustion zone in the area connected with the main combustion stage nozzle bundle area. The burner body adopts staged combustion technology: only the duty class works in the small state, and the duty class and the main combustion stage work simultaneously in the large state.

The air inlet is arranged on the outer shell body close to the smoke outlet end.

The duty class fuel pipe is provided with one, and the main combustion class fuel pipes are provided with at least two.

The combustion chamber of this embodiment includes a burner 4, which is arranged at the head of the outer shell 2 and connected to the flame tube 3 and arranged together in the outer shell 2. The combustion device 1 and the flame tube 4 form an air intake cavity 23, and an air intake port 21 is opened at the bottom of the combustion chamber 2. The air flows into the outer shell 2 along the air flow direction 22 through the air intake port 21, and flows toward the burner 4 along the air intake cavity 23, and finally enters the nozzle bundle through the air intake hole 45A on the nozzle bundle. The internal cylindrical area formed by the flame tube is the combustion zone of the combustion chamber, and the combustion zone of the combustion chamber is divided into a duty class combustion zone 31 and a main combustion stage combustion zone 32.

As shown in Fig. 3-4, the burner body 4 adopts a main combustion stage and a duty class stage combustion mode. Two main combustion stage fuel pipes 41 and a duty class fuel pipe 42 are arranged at the front end of the burner body 4, wherein the main combustion stage fuel pipes 41 are symmetrically distributed, and the duty class fuel pipes 42 are located on the center line of the burner body 4. The number of layers of the main combustion stage nozzle bundle is preferably 3 to 8 layers, and in this embodiment, 3 layers are arranged in a staggered manner to reduce the influence of the air intake of the outer layer bundle on the air intake of the inner layer bundle. The number of layers of the duty nozzle micro-pre-bundle is preferably 1 to 2 layers; in this embodiment, 1 layer is used. The main combustion stage nozzle bundle 45 surrounds the duty class nozzle bundle 46, surrounding it 360°, which is conducive to flame transmission and flame stabilization. In addition, the fuel bin and the air partition plate 47 isolate the air intake cavity and the fuel supply area from each other, and the burner body end cover 48 is close to the outlet of the nozzle bundle, isolating the air intake cavity and the flame tube combustion area 24.

The fuel flows into the main combustion stage fuel bunker 43 and the duty class fuel bunker 44 respectively through the main combustion stage fuel inlet 41A and the duty class fuel inlet 42A along the fuel flow direction 49. The fuel is evenly dispersed in the fuel bunker, and then flows into the main combustion stage nozzle bundle 45 and the duty class nozzle bundle 46 respectively from the nozzle bundle fuel inlet 45B at the end of the nozzle bundle, and flows downstream after mixing with the air in the tube. The mixed premixed gas flows into the combustion zone of the flame tube and participates in combustion in the main combustion stage combustion zone 32 and the duty class combustion zone 31 respectively.

As shown in FIG5 , the main combustion stage nozzle bundle 45 and the duty class nozzle bundle 46 in this embodiment adopt the same structure, so the main combustion stage nozzle bundle 45 will be described in detail below. The fuel inlet 45B is located at the upper end of the main combustion stage nozzle bundle 45 and is connected to the main combustion stage fuel bin 43; the air inlet hole 45A is arranged on the side wall of the main combustion stage nozzle bundle 45, and can adopt a circular hole or a strip hole structure. In this embodiment, a circular hole is selected, and the number of rows of air holes along the axis is preferably 1 to 2 rows, and the number of rows in this embodiment is 1 row. A diverter 45D is arranged near the nozzle bundle outlet, and the diverter 45D divides the area inside the nozzle bundle into a mainstream area 45E and a flame stabilization area 45F. The mainstream area 45E is inside, and the flame stabilization area 45F is close to the wall. In order to prevent flashback, the height of the straight wall section cavity at the entrance of the flame stabilization area should be small enough, so as to use the quenching effect of the wall to prevent flashback. In this embodiment, the ratio of the entrance area of the mainstream area and the flame stabilization area is 100. In addition, a swirl blade 45C is provided at the entrance of the flame stabilizing zone 45F. The axial angle of the swirl blade is 20°. Since the height of the straight wall section cavity is very small, it is difficult to form a swirl structure. In order to smoothly form a swirl structure at the outlet, the outer wall of the flame stabilizing zone 45F adopts an expansion structure. In this embodiment, the expansion ratio is 1.5.

The fuel and air flow into the main combustion stage nozzle bundle 45 from the nozzle bundle fuel inlet 45B and the air inlet hole 45A respectively, and then mix in the nozzle bundle while flowing downstream along the mixture flow direction 410. After flowing through the diverter pipe 45D, the mixture is divided into two airflows, which flow into the mainstream area 45E and the flame stabilization area 45F respectively. Among them, the airflow in the mainstream area 45F maintains the original flow state and continues to flow downstream, and finally flows out of the nozzle bundle; the airflow in the flame stabilization area 45F is first disturbed by the inlet swirl blades, and then rotates in the flame stabilization area, and gradually expands and decelerates, and finally flows out of the nozzle bundle, forming a swirl structure around the mainstream, and participates in combustion in the combustion area of the combustion chamber together with the mixture in the mainstream area.

In the present embodiment, the upstream structures of the main combustion stage nozzle bundle 45 and the duty stage nozzle bundle 46 are not changed, and the space occupancy of the mainstream area is much larger than that of the flame stabilization area, while the mainstream area does not change the flow state of the upstream mixed gas. Therefore, the present invention retains all the technical advantages of the micro-premixed burner; the inlet of the flame stabilization area adopts a swirl blade structure, and with the assistance of the expansion structure, the mixed gas in the flame stabilization area eventually forms a swirl structure around the mainstream, which plays a role in stabilizing the ignition source. Therefore, the present invention also takes into account the superior stability performance of the conventional swirl combustion chamber.

Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims (6)

1. A combination gas turbine combustor, characterized by: the combustion device is arranged in the outer shell, an air inlet cavity is formed between the outer wall of the combustion device and the inner wall of the outer shell, and an air inlet communicated with the air inlet cavity is arranged on the outer shell;

The combustion device comprises a combustor and a flame tube, wherein a nozzle tube bundle area is arranged on the combustor, a nozzle tube bundle is arranged in the nozzle tube bundle area, the nozzle tube bundle comprises a duty-level nozzle tube bundle arranged in the middle of the combustor and a main combustion-level nozzle tube bundle arranged at the periphery of the duty-level nozzle tube bundle, an upper port and a lower port are arranged on the flame tube, the upper port of the flame tube is arranged at the periphery of the nozzle tube bundle area, and a flue gas outlet communicated with the lower port of the flame tube is arranged on an outer shell;

The burner is provided with a fuel supply area in the direction opposite to the nozzle tube bundle area, and the fuel supply area comprises an duty-stage fuel cavity for supplying fuel to the duty-stage nozzle tube bundle and a main combustion-stage fuel cavity for supplying fuel to the main combustion-stage nozzle tube bundle;

The periphery of the nozzle tube bundle area is provided with a gas distribution cavity wrapping the nozzle tube bundle area, the gas distribution cavity is communicated with an air inlet cavity, the front part of the nozzle tube bundle, which is close to the fuel supply area, is a premixing section, the rear part of the nozzle tube bundle, which is close to the flame tube, is a diversion section,

The diversion section comprises a middle main flow area and an annular flame stabilizing area arranged at the periphery of the main flow area,

A shunt tube is arranged at a position close to the outlet of the nozzle tube bundle, and divides the inner area of the nozzle tube bundle into a main flow area and a flame stabilizing area; swirl vanes are arranged at the inlet of the flame stabilizing region, and the outer wall of the flame stabilizing region adopts an expansion structure;

the main flow area and the flame stabilizing area are both communicated with the premixing section, a swirl vane is arranged at the joint of the flame stabilizing area and the premixing section, the axial angle of the swirl vane is 5-30 degrees, the end part of the premixing section is provided with a fuel inlet communicated with the fuel supply area, and the peripheral wall of the premixing section is provided with an air inlet communicated with the air distribution cavity.

2. The combination gas turbine combustor as set forth in claim 1, wherein: the inner diameters of the main combustion stage nozzle tube bundle and the duty stage nozzle tube bundle are 5-12 mm, and the lengths are 15-120 mm.

3. The combination gas turbine combustor as set forth in claim 1, wherein: and a class fuel pipe is arranged in the class-on-duty fuel cavity, and a main fuel pipe is arranged in the main fuel cavity.

4. The combination gas turbine combustor as set forth in claim 1, wherein: the flame tube forms an on-duty combustion zone in a zone communicated with the on-duty nozzle tube bundle zone, and forms a main combustion zone in a zone communicated with the main combustion nozzle tube bundle zone.

5. The combination gas turbine combustor as set forth in claim 1, wherein: the air inlet is arranged on the outer shell body and is close to the flue gas outlet end.

6. The combination gas turbine combustor as set forth in claim 1, wherein: the on-duty grade fuel pipe is provided with 1, and the main combustion grade fuel pipe is provided with 2 at least.