CN115164231B

CN115164231B - Low-emission combustor

Info

Publication number: CN115164231B
Application number: CN202210851289.2A
Authority: CN
Inventors: 李洁; 马宏宇; 王艳丽; 陈明禄
Original assignee: AECC Shenyang Engine Research Institute
Current assignee: AECC Shenyang Engine Research Institute
Priority date: 2022-07-19
Filing date: 2022-07-19
Publication date: 2023-06-20
Anticipated expiration: 2042-07-19
Also published as: CN115164231A

Abstract

The present application provides a low emission combustor comprising: premix assembly, flame tube assembly and nozzle assembly, wherein: the premixing assembly comprises a front casing, a premixing bushing, a premixing chamber mounting edge, a premixing chamber wall surface, a cyclone, an air inlet pipe, an air entraining pipe, a blocking block and a spring; the nozzle assembly comprises a nozzle body and a spray rod; the flame tube assembly comprises a rear casing, a flame tube lining, a flame tube outer wall, a flame tube inner wall and an air supply bent pipe. By dividing the air entering the combustion chamber head and the air entering the blending holes into two separate passages. In a low working condition, the air quantity entering the premixing component is controlled in a interception mode by arranging a spring and a blocking block on an air inlet pipe of the premixing component, so that the proportion of the air entering a main combustion zone is reduced, the oil-gas ratio is proper, and the combustion stability in the low working condition is ensured; under the high working condition, the spring returns gradually, the air quantity in the air inlet pipe and the air inlet pipe is automatically distributed according to the area of the air inlet pipe, the temperature of the main combustion area is ensured to be in the range of 1670K-1900K, and the low emission requirement is met.

Description

Low-emission combustor

Technical Field

The application belongs to the technical field of gas turbines, and particularly relates to a low-emission combustor.

Background

With the increasing environmental protection requirements, increasingly stringent emission standards are set for emission control of NOx, CO, which are environmentally severe in gas turbine emissions. For industrial gas turbines, failure to meet the pollutant emission standards will not be a commercial market, i.e., pollutant emission levels are the admission thresholds for gas turbines to enter the market.

The lean premixed combustion (Lean Premixed Combustion) technology is the most mature and widely applied dry low-emission combustion technology in the current technology, and the working principle of the technology is to control the temperature of a main combustion area of a combustion chamber within a narrow temperature range of 1670K-1900K so as to control the generation of thermal nitrogen oxides (NOx) which are mainly used in pollutants and simultaneously give consideration to the emission of carbon monoxide (CO). This would mean that a low emission combustor would have a significant amount of air entering the combustor main combustion zone from the burner head for the purpose of lowering the main combustion zone temperature. However, the gas-oil ratio in the main combustion zone is too low to achieve stable combustion under low operating conditions.

In order to solve the problem that combustion stability under low working conditions and pollutant emission under high working conditions contradict each other, a fuel classification and flame tube head air partition combined mode is generally adopted by a low-emission combustor, namely, a fuel feeding mode under different working conditions is controlled, a diffusion combustion mode is guaranteed to be realized under the low working conditions so as to keep combustion stability, and a premixed combustion mode is adopted under the high working conditions so as to control pollutant emission. However, in the prior art, the head structure and the nozzle structure of the low-emission combustor are complex, and meanwhile, the fuel classification control has the switching actions of fuels at all levels under different working conditions, so that the complexity of a fuel control system is increased, and the cost is high.

Disclosure of Invention

It is an object of the present application to provide a low emission burner that solves or alleviates at least one of the problems of the background art.

The technical scheme of the application is as follows: a low emission combustor, the low emission combustor comprising: premix assembly, flame tube assembly and nozzle assembly, wherein:

the premixing assembly comprises a front casing, a premixing bushing, a premixing chamber mounting edge, a premixing chamber wall surface, a cyclone, an air inlet pipe, an air entraining pipe, a blocking block and a spring;

the premixing lining is arranged on the inner side of the front casing, the rear end of the premixing lining is pressed between the front casing and the rear casing, a first annular channel is formed between the premixing lining and the front casing, and a premixing rectifying hole is formed in the premixing lining along the central line direction;

the premixing chamber is arranged along the central line of the premixing chamber and is pressed between the front casing and the rear casing;

the wall surface of the premixing chamber is arranged on the mounting edge of the premixing chamber and forms a shrinkage structure along the central line;

the air inlet pipe penetrates through the front casing and is communicated with the first annular channel, the air entraining pipe is led out from one side of the air inlet pipe, the block mounting edge is led out from the other side of the air inlet pipe, the block is slidably mounted in the block mounting edge, the spring mounting edge is fixedly connected to the block mounting edge, and the spring is mounted between the spring mounting edge and the block;

the nozzle assembly comprises a nozzle body and a spray rod, wherein a flange which extends radially is arranged on the outer side of the nozzle body, the nozzle body and the front casing are fixed in pairs through the flange, the nozzle body is provided with a first part which penetrates through a cyclone and enters the wall surface of the premixing chamber, the first part and the wall surface of the premixing chamber form a premixing chamber, the center of the nozzle body is provided with oil holes along the central line, the nozzle body is provided with a plurality of oil injection holes which are distributed circumferentially and are communicated with the oil holes, and the spray rod is arranged at the position of the oil injection holes and is communicated with the oil injection holes;

the flame tube assembly comprises a rear casing, a flame tube lining, a flame tube outer wall, a flame tube inner wall and an air supply bent tube, wherein the rear casing is fixedly connected with the front casing; the flame tube lining is arranged on the inner side of the rear casing, a second annular channel is formed between the flame tube lining and the rear casing, the flame tube outer wall and the flame tube inner wall are sequentially arranged on the inner side of the flame tube lining, so that a third annular channel is formed between the flame tube outer wall and the flame tube lining, a fourth annular channel is formed between the flame tube inner wall and the flame tube outer wall, and lining rectifying holes, first cooling holes and inner wall through holes are respectively formed on the flame tube lining, the flame tube outer wall and the flame tube inner wall; one end of the air supply bent pipe is connected with the air guide pipe, and the other end of the air supply bent pipe penetrates through the rear casing and is communicated with the second annular channel.

Further, the premix and rectifying holes are positioned on one side, far away from the swirler, of the premix bushing.

Further, the air guide pipe and the axis of the installing edge of the blocking block are arranged in a collinear manner.

Further, the oil spray hole is positioned at the left side of the cyclone.

Further, the spray rod is provided with one or more small oil injection holes in the radial direction.

Further, the lining rectifying holes, the first cooling holes and the inner wall through holes are staggered in the direction of the central line.

Further, in the fourth annular passage, the passage pitch at the inner wall through hole is larger than the passage pitch at other positions than the inner wall through hole.

Further, the inner wall through hole includes a blending hole and a second cooling hole, which are arranged back and forth in the airflow flowing direction, and the number of turns of the blending hole is smaller than that of the second cooling hole.

The low emission burner provided herein divides air entering the combustion chamber head and air entering the blending bore into two independent passages by employing an air staging control scheme. In a low working condition, the air quantity entering the premixing component is controlled in a interception mode by arranging a spring and a blocking block on an air inlet pipe of the premixing component, so that the proportion of the air entering a main combustion zone is reduced, the oil-gas ratio is proper, and the combustion stability in the low working condition is ensured; under the high working condition, the spring returns gradually, the air quantity in the air inlet pipe and the air inlet pipe is automatically distributed according to the area of the air inlet pipe, the temperature of the main combustion area is ensured to be in the range of 1670K-1900K, and the low emission requirement is met.

Drawings

In order to more clearly illustrate the technical solutions provided by the present application, the following description will briefly refer to the accompanying drawings. It will be apparent that the figures described below are only some embodiments of the present application. FIG. 1 is a schematic view of a low emission combustor configuration of the present application.

Reference numerals:

1-premix assembly

11-front casing

12-a premix liner, which is provided with a plurality of holes,

121-premixing rectifying hole

13-premix chamber mounting edge

14-premixing chamber wall

15-cyclone

16-air inlet pipe

17-bleed air pipe

18-block

181 blocking mounting edge

19-spring

191-spring mounting edge 2-flame tube assembly

21-rear casing

22-flame tube liner

221-liner rectifying hole

23-flame tube outer wall

231-first cooling holes

24-inner wall of flame tube

241-blending holes

242-second cooling holes

25-air supply elbow 3-nozzle assembly

31-nozzle body

311-flange

312-oil hole

32-spray rod

Detailed Description

In order to make the purposes, technical solutions and advantages of the implementation of the present application more clear, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the accompanying drawings in the embodiments of the present application.

As shown in fig. 1, the low emission burner provided in the present application includes: the premixing assembly 1, the flame tube assembly 2 and the nozzle assembly 3 are connected through bolts.

Specifically, the premix assembly 1 mainly comprises a front casing 11, a premix liner 12, a premix chamber mounting edge 13, a premix chamber wall 14, a swirler 15, an air inlet pipe 16, an air bleed pipe 17, a block 18 and a spring 19.

The premix liner 12 is disposed inside the front casing 11, and the rear end of the premix liner 12 is pressed between the front casing 11 and the rear casing 21 with a certain gap between the premix liner 12 and the front casing 11, so that the first annular passage a can be formed. Wherein, the premix liner 12 is provided with one or more circles of premix and rectifying holes 121 along the direction of the central line C. In the preferred embodiment of the present application, premix swirl holes 121 are two turns and are located on the side of premix liner 12 that is remote from swirler 15.

The premix chamber mounting rim 13 is generally L-shaped, extends along a centerline C, and is also compressed between the front and rear cases 11, 21.

The premix chamber wall 14 is in a contracted configuration along the centerline C, which is mounted on the premix chamber mounting rim 13.

The swirler 15 is mounted inside the front end of the premixing chamber wall 14.

The intake pipe 16 communicates through the front case 11 into the first annular passage a.

The air intake pipe 17 is led out from the right side of the air intake pipe 16, the block mounting edge 181 is led out from the left side of the air intake pipe 16, and the block 18 is movably mounted in the block mounting edge 181. In the preferred embodiment of the present application, the bleed air duct 17 is arranged in line with the axis of the block mounting edge 181. However, it should be noted that the bleed air pipe 17 may also be disposed outside the axis of the block mounting edge 181, i.e. the axis of the bleed air pipe 17 is closer to the inlet of the lower end of the air inlet pipe 16, and one side of the bleed air pipe 17 may still automatically distribute air when the block 18 moves along the block mounting edge 181 to block the air inlet pipe 16.

When the block 18 moves along the block mounting edge 181, the block 18 can extend into the air inlet pipe 16, thereby partially or completely shielding air flowing from the air inlet pipe 16 to the first annular channel a. A spring mounting edge 191 is fixedly connected to the left side of the block mounting edge 181, and a spring 19 is mounted on the spring mounting edge 191 for providing an elastic force to the block 18.

The nozzle assembly 3 is mainly composed of a nozzle body 31 and a spray bar 32. The outer side of the nozzle body 31 has a radially extending flange 311, by means of which flange 311 the nozzle body 31 can be fixed to the front housing 11. The left side of the nozzle body 31 passes through the swirler 15 into the premix chamber wall 14, which forms a premix chamber with the premix chamber wall 14. The center of the nozzle body 31 has an oil passage hole 312 along the center line C, and fuel enters from the oil passage hole 312. The nozzle body 31 has a plurality of oil injection holes distributed circumferentially and communicating with the oil passage holes 312 at about the middle position, the oil injection holes being located on the left side of the swirler 2. The spray bar 32 is mounted on and communicates with the spray hole so that the fuel in the oil passage hole 312 can be sprayed along the spray bar 32. Wherein the spray bar 32 has one or more orifices in the radial direction.

The flame tube assembly 2 mainly comprises a rear casing 21, a flame tube lining 22, a flame tube outer wall 23, a flame tube inner wall 24 and an air supply elbow 25.

The front end of the rear casing 21 is fixedly connected with the rear end of the front casing 11 through a connecting piece.

The liner 22 is disposed inside the rear case 21, and the front end of the liner 22 is pressed between the front case 11 and the rear case 21 with a certain gap between the liner 22 and the rear case 21, so that the second annular passage B can be formed.

The outer wall 23 and the inner wall 24 are disposed inside the liner 22 in sequence, the front ends of the outer wall 23 and the inner wall 24 are supported between the mounting edge 13 and the wall 14, and the rear ends of the outer wall 23 and the inner wall 24 can be fixed and mounted to the rear end of the rear casing 21 by welding. There is a gap between the liner outer wall 23 and the liner sleeve 22 that forms a third annular channel D. There is also a gap between the inner wall 24 of the flame tube and the outer wall 23 of the flame tube, which gap forms a fourth annular channel E. Wherein, the liner rectifying hole 221, the first cooling hole 231 and the inner wall through hole are respectively arranged on the liner 22, the outer wall 23 and the inner wall 24 of the liner, the inner wall through hole comprises a mixing hole 241 and a second cooling hole 242, the mixing hole 241 and the second cooling hole 242 are arranged front and back in the airflow flowing direction, and the number of turns of the mixing hole 241 is less than that of the second cooling hole 242.

Further, in the fourth annular channel E, the pitch at the through holes having the inner wall is larger than the pitch at other positions.

In the preferred embodiment of the present application, the liner rectifying holes 221, the first cooling holes 231, and the inner wall through holes are staggered in the center line direction. For example, in the embodiment shown in fig. 1, the inner wall through hole is located at the rear side of the inner wall 24 of the liner, the first cooling hole 231 is located at the front side of the outer wall 23 of the liner, and the liner rectifying hole 221 is located at the rear side of the liner 22 of the liner.

One end of the air supply bent pipe 25 is connected with the air guide pipe 17, and the other end passes through the rear casing 21 to be communicated with the second annular channel B.

When air enters the combustion chamber inlet through the air inlet pipe 16, the air is divided into two parts, and one part enters the premixing assembly 1 along the rear section of the air inlet pipe 16 to serve as air in a main combustion area; the other part enters the flame tube assembly 2 along the air supply bent pipe 25 through the air guide pipe 17 to serve as mixing air and cooling air.

Because the air ratio of the main combustion area of the low-emission combustion chamber is large, the oil-gas ratio of the main combustion area is very low under the low working condition, and stable combustion cannot be ensured, and the oil-gas ratio of the main combustion area is improved by reducing the air of the main combustion area or increasing the fuel quantity so as to ensure the working stability of the combustion chamber.

With continued reference to FIG. 1, in the present application, the increase in the fuel/air ratio of the main combustion zone is achieved by reducing the air in the main combustion zone under low operating conditions.

In low operating conditions, the block 18 is pushed to move to the right by an external displacement driving device (such as a cylinder or a linear motor), and the block 18 moves to the right into the air inlet pipe 16, so that the air flow area to the premixing assembly 1 is reduced at the three-way position, namely the air proportion of the main combustion area is reduced. The greater the displacement of the block 18 to the right, the lower the proportion of air that is distinguished by the main combustion. The air entering the premix assembly 1 enters the first annular passage A, then enters the front section of the premix assembly 1 through the premix flow-straightening holes 121 on the premix liner 12, and enters the premix chamber formed by the nozzle body 31 and the premix chamber wall 14 through the swirler 15, and the air is premixed with the fuel injected by the spray bars 32 on the nozzle assembly 3, and the sum enters the flame tube for combustion. The other part of air sequentially passes through the air guide pipe 17 and the air supply bent pipe 25 to enter the second annular channel B, and then enters the third annular channel D formed by the flame tube lining 23 and the flame tube outer wall 24 through the lining rectifying hole 221 on the flame tube lining 22; then the flame tube inner wall 24 is subjected to impact cooling through the first cooling hole C on the flame tube outer wall 23 and enters a fourth annular channel E formed by the flame tube outer wall 23 and the flame tube inner wall 24, wherein the part of air is firstly utilized to perform impact cooling on the flame tube inner wall 18; the part of air continues to flow rightward in the fourth annular channel E to the rear section of the flame tube, enters the rear section of the flame tube through the mixing holes 241 and the second cooling holes 242 on the inner wall 24 of the flame tube, continues to be mixed with hot fuel gas from the main combustion zone for combustion, further reduces CO emission, realizes the secondary utilization of the part of air, and cools the rear section of the flame tube by the cooling air from the second cooling holes 242.

The fuel is sprayed out through the spray rod 3 in the nozzle assembly 3 and the fuel spray hole at the right end of the nozzle body 31, and the two fuel parts are a fuel inlet and are automatically distributed. The fuel injected by the spray boom 32 enters the premixing chamber under the action of the cyclone 2 and is premixed with air in the premixing chamber, so that a premixed combustion mode is realized, and pollutant emission is reduced; the fuel injected from the fuel hole at the right end of the nozzle body 31 is directly combusted in the main combustion zone, and maintains combustion stability in the diffusion combustion mode.

Under the high working condition, under the action of the spring 19, the blocking block 18 is reset to move to the left, most of air enters the premixing assembly 1 along the air inlet pipe 16 to be premixed with oil gas, and then is used for secondary combustion with the air in the flame tube assembly 2 on the right side, so that NOx emission is reduced.

According to the method, the air proportion entering the premixing component 1, namely the main combustion area, is controlled by adjusting the movement of the blocking block 18 under different working conditions, so that the oil-gas ratio of the main combustion area is adjusted, the temperature of the main combustion area is adjusted to be in a 1670K-1900K range meeting low emission while the combustion stability is ensured, and the working condition range meeting low emission is further widened.

The low emission burner provided herein divides air entering the combustion chamber head and air entering the blending bore into two independent passages by employing an air staging control scheme. In the low working condition, the air quantity entering the premixing assembly 1 is controlled in a interception mode by arranging a spring 19 and a blocking block 18 on the air inlet pipe 16 of the premixing assembly 1, so that the proportion of the air entering a main combustion zone is reduced, the oil-gas ratio is proper, and the combustion stability in the low working condition is ensured; under the high working condition, the spring 18 gradually returns, the air quantity in the air inlet pipe 16 and the air inlet pipe 17 is automatically distributed according to the area of the air inlet pipe, the temperature of the main combustion area is ensured to be in the range of 1670K-1900K, and the low emission requirement is met.

The low-emission burner can be applied to the flame tube head of the single-stage cyclone, so that the whole structure of the burner can be simplified.

In the low-emission combustor, the fuel system does not need to be graded, the adjustment of the whole working condition range can be realized only by adopting single-stage fuel control, the large fluctuation of the whole engine power in the high-low working condition adjustment process can not be caused, and the fuel control system is simple.

The low-emission combustor can guarantee the temperature of the main combustion zone in a range conforming to low emission in a wide range by adjusting the air inflow in the premixing component, and meanwhile, the range of working conditions meeting the low emission of NOx/CO is wide.

The foregoing is merely specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions easily conceivable by those skilled in the art within the technical scope of the present application should be covered in the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A low emission combustor, the low emission combustor comprising: premix assembly (1), flame tube assembly (2) and nozzle assembly (3), wherein:

the premixing assembly (1) comprises a front casing (11), a premixing bushing (12), a premixing chamber mounting edge (13), a premixing chamber wall surface (14), a cyclone (15), an air inlet pipe (16), an air entraining pipe (17), a blocking block (18) and a spring (19);

the premixing bushing (12) is arranged on the inner side of the front casing (11), the rear end of the premixing bushing (12) is pressed between the front casing (11) and the rear casing (21), a first annular channel (A) is formed between the premixing bushing (12) and the front casing (11), and a premixing rectifying hole (121) is formed in the premixing bushing (12) along the direction of a central line (C);

the premixing chamber mounting edge (13) extends along a central line (C) and is pressed between the front casing (11) and the rear casing (21);

the premixing chamber wall surface (14) is arranged on the premixing chamber installation edge (13) and forms a shrinkage structure along the central line (C);

the air inlet pipe (16) passes through the front casing (11) and is communicated with the first annular channel (A), the air entraining pipe (17) is led out from one side of the air inlet pipe (16), the block mounting edge (181) is led out from the other side of the air inlet pipe (16), the block (18) is slidably mounted in the block mounting edge (181), the block mounting edge (181) is fixedly connected with a spring mounting edge (191), and the spring (19) is mounted between the spring mounting edge (191) and the block (18);

the nozzle assembly (3) comprises a nozzle body (31) and a spray rod (32), wherein a radially extending flange (311) is arranged on the outer side of the nozzle body (31), the nozzle body (31) and a front casing (11) are fixed by the flange (311), the nozzle body (31) is provided with a first part penetrating through a cyclone (15) and entering a premixing chamber wall surface (14), the first part and the premixing chamber wall surface (14) form a premixing chamber, an oil through hole (312) is formed in the center of the nozzle body (31) along a central line (C), a plurality of oil spray holes which are circumferentially distributed and communicated with the oil through hole (312) are formed in the nozzle body (31), and the spray rod (32) is arranged at the position of the oil spray holes and is communicated with the oil spray holes;

the flame tube assembly (2) comprises a rear casing (21), a flame tube lining (22), a flame tube outer wall (23), a flame tube inner wall (24) and an air supply bent tube (25), wherein the rear casing (21) is fixedly connected with the front casing (11); the flame tube lining (22) is arranged on the inner side of the rear casing (21), a second annular channel (B) is formed between the flame tube lining and the rear casing (21), the flame tube outer wall (23) and the flame tube inner wall (24) are sequentially arranged on the inner side of the flame tube lining (22), so that a third annular channel (D) is formed between the flame tube outer wall (23) and the flame tube lining (22), a fourth annular channel (E) is formed between the flame tube inner wall (24) and the flame tube outer wall (23), and lining rectifying holes (221), first cooling holes (231) and inner wall through holes are respectively formed in the flame tube lining (22), the flame tube outer wall (23) and the flame tube inner wall (24); one end of the air supply bent pipe (25) is connected with the air guide pipe (17), and the other end of the air supply bent pipe passes through the rear casing (21) to be communicated with the second annular channel (B).

2. The low emission combustor of claim 1, wherein the premix swirl holes (121) are located on a side of the premix liner (12) remote from the swirler (15).

3. A low emission burner as claimed in claim 1, characterised in that the bleed air duct (17) is arranged co-linear with the axis of the block mounting edge (181).

4. The low emission burner as claimed in claim 1, characterised in that the oil jet is located on the left side of the swirler (15).

5. The low emission burner as claimed in claim 1, wherein said spray bar (32) has one or more small fuel injection holes in a radial direction.

6. The low emission combustor of claim 1, wherein the liner rectifying holes (221), the first cooling holes (231), and the inner wall through holes are staggered in a centerline direction.

7. The low-emission burner as claimed in claim 6, wherein in the fourth annular passage (E), the passage pitch at the inner wall through hole is larger than the passage pitch at other positions than the inner wall through hole.

8. The low-emission burner as claimed in claim 6 or 7, wherein the inner wall through hole comprises a blending hole (241) and a second cooling hole (242), the blending hole (241) and the second cooling hole (242) are arranged one after the other in the airflow flow direction, and the number of turns of the blending hole (241) is smaller than the number of turns of the second cooling hole (242).