Low nitrogen oxide emission combustor for gas turbine and gas turbine

Abstract

The present invention discloses a low nitrogen oxide emission combustion chamber for a gas turbine and a gas turbine. The low nitrogen oxide emission combustion chamber for a gas turbine comprises a flame tube and a swirl premixing section arranged at the first end of the flame tube, and a main combustion stage feed pipe and a precombustion stage feed pipe are arranged on the swirl premixing section; the swirl premixing section comprises a swirl top plate and a plurality of swirl blades arranged around one side of the swirl top plate, the first end of the swirl blade is connected to the swirl top plate, a fuel channel is arranged inside the swirl blade, and the first end of the fuel channel passes through the swirl top plate, and the second end of the fuel channel extends to the second end of the swirl blade; the main combustion stage feed pipe is arranged on the swirl top plate and communicated with the first end of the fuel channel, and the precombustion stage feed pipe is arranged on the swirl top plate and passes through the swirl top plate and extends to the area where the plurality of swirl blades are located. The structure has high reliability and stable operation.

Description

Technical Field

[0001] The present invention relates to the technical field of gas turbines, and in particular to a low nitrogen oxide emission combustion chamber for a gas turbine and a gas turbine. Background Art

[0002] Micro gas turbines have the characteristics of compact structure, light weight and low maintenance cost, and are widely used in the field of distributed power generation. The combustion products of micro gas turbines contain nitrogen oxides (NOx), which mainly include nitric oxide (NO) and nitrogen dioxide (NO2). Nitric oxide is a colorless and odorless gas. If the concentration of nitric oxide in the atmosphere reaches a certain level, it will combine with hemoglobin in the blood, causing blood hypoxia and thus central nervous system paralysis. Nitrogen dioxide is a red toxic gas that irritates the human respiratory organs and can easily cause emphysema and lung cancer. Nitrogen dioxide can also destroy ozone and form ozone holes. Therefore, technical measures should be taken as much as possible to reduce the emission of nitrogen oxides from micro gas turbines.

[0003] In a micro gas turbine, the temperature of the combustion gas in the combustion chamber has a great influence on nitrogen oxides. The output and generation rate of nitrogen oxides increase exponentially with the increase of combustion temperature. Therefore, the key to reducing the emission of nitrogen oxides from a micro gas turbine is to control the temperature in the combustion chamber at a low level (generally 1700K-1900K, if the temperature is lower, it will affect the combustion efficiency) and make the temperature distribution in the combustion chamber uniform.

[0004] The existing widely used low-emission gas combustion chamber has only one-stage radial swirler, and the main combustion stage fuel is injected through a fuel nozzle. The fuel nozzle is welded a lot in actual processing, and welding deformation is difficult to guarantee. At the same time, it is easy to bump and cause deformation and damage of the small diameter fuel nozzle. Summary of the invention

[0005] The embodiments of the present invention provide a low nitrogen oxide emission combustion chamber for a gas turbine and a gas turbine, so as to solve the problem that the welding deformation of the main combustion stage fuel nozzle of the low emission gas combustion chamber is difficult to ensure and is easily damaged by collision.

[0006] On the one hand, an embodiment of the present invention proposes a low nitrogen oxide emission combustion chamber for a gas turbine, comprising a flame tube and a swirl premixing section arranged at the first end of the flame tube, the swirl premixing section being provided with a main combustion stage feed pipe and a precombustion stage feed pipe; the swirl premixing section comprises a swirl top plate and a plurality of swirl blades arranged around one side of the swirl top plate, the first end of the swirl blade is connected to the swirl top plate, a fuel channel is arranged inside the swirl blade, and the first end of the fuel channel passes through the swirl top plate, and the second end of the fuel channel extends to the second end of the swirl blade; the main combustion stage feed pipe is arranged on the swirl top plate and is connected to the first end of the fuel channel, and the precombustion stage feed pipe is arranged on the swirl top plate and passes through the swirl top plate and extends to the area where the plurality of swirl blades are located.

[0007] According to one aspect of an embodiment of the present invention, the first end of the flame tube is sleeved in the casing, and the second end of the flame tube extends to the outside of the casing; one end of the main combustion stage feed pipe is arranged in the swirl premixing section, and the other end of the main combustion stage feed pipe extends to the outside of the casing; one end of the precombustion stage feed pipe is arranged in the swirl premixing section, and the other end of the precombustion stage feed pipe extends to the outside of the casing.

[0008] According to one aspect of the embodiments of the present invention, the casing has an air inlet for providing air for combustion.

[0009] According to one aspect of an embodiment of the present invention, a first end of the flame tube is provided with a plurality of cooling holes, and the plurality of cooling holes are arranged axially around the flame tube.

[0010] According to one aspect of the embodiment of the present invention, mixing holes are arranged on the body of the flame tube, and the mixing holes are arranged around the axial direction of the flame tube.

[0011] According to one aspect of an embodiment of the present invention, an annular channel is provided on the side of the swirl top plate away from the swirl blades, and the fuel channel inside the swirl blades is connected to the annular channel; an annular swirl cover plate is provided on the side of the swirl top plate away from the swirl blades, and the swirl cover plate is arranged at the position corresponding to the annular channel to seal the annular channel; the main combustion stage feed pipe is arranged on the swirl cover plate and is connected to the annular channel to communicate with the fuel channel.

[0012] According to one aspect of the embodiment of the present invention, the swirl premixing section further includes an annular swirl bottom plate, and the swirl top plate, swirl blades and swirl bottom plate are arranged in sequence.

[0013] According to one aspect of an embodiment of the present invention, the fuel channel includes an axial channel and a radial channel that are interconnected and arranged in sequence from the first end of the swirl blade to the second end of the swirl blade, and the outlet of the radial channel is located in the inner ring of the ring formed by multiple swirl blades.

[0014] According to one aspect of the embodiments of the present invention, there are multiple radial channels, and the multiple radial channels are arranged in sequence along the extension direction of the swirl blades, and the multiple radial channels are all connected to the axial channel.

[0015] On the other hand, an embodiment of the present invention provides a gas turbine, comprising the low nitrogen oxide emission combustor for a gas turbine as described above.

[0016] In the low nitrogen oxide emission combustion chamber for a gas turbine provided by an embodiment of the present invention, a pre-combustion stage feed pipe and a main combustion stage feed pipe share a swirl premixing section, the pre-combustion stage feed pipe extends into the interior of the swirl premixing section, fuel is ejected from the pre-combustion stage feed pipe, the fuel is mixed with air entering the swirl premixing section through the gaps between the swirl blades and burns, when the gas turbine reaches a specified operating condition, fuel enters the fuel channel inside the swirl blades from the main combustion stage feed pipe, and is then ejected from the fuel channel, the fuel is mixed with air entering the swirl premixing section through the gaps between the swirl blades and burns, the swirl blade trailing edge injection is used as the injection method for the main combustion stage fuel, a lean premixed combustion chamber is realized, low nitrogen oxide emissions are achieved, the structural reliability is high, and the operation is stable, and the problems of the main combustion stage fuel nozzle being difficult to guarantee welding deformation and being easily damaged by bumps and collisions in existing low-emission gas combustion chambers are solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments of the present invention are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 The diagram is a schematic structural diagram of a low nitrogen oxide emission combustion chamber for a gas turbine according to an embodiment of the present invention.

[0019] Figure 2 The figure is a schematic structural diagram of a flame tube of a low nitrogen oxide emission combustion chamber for a gas turbine according to an embodiment of the present invention.

[0020] Figure 3 It is a schematic cross-sectional structural diagram of a partial structure of a low nitrogen oxide emission combustion chamber for a gas turbine according to an embodiment of the present invention.

[0021] Figure 4 The cross-sectional structure diagram of a swirl blade for a low nitrogen oxide emission combustion chamber of a gas turbine according to an embodiment of the present invention.

[0022] Figure 5 Another cross-sectional structural schematic diagram of a swirl blade for a low nitrogen oxide emission combustion chamber of a gas turbine according to an embodiment of the present invention.

[0023] In the attached figure:

[0024] 100-flame tube, 200-swirl premixing section, 300-main combustion stage feed pipe, 400-precombustion stage feed pipe, 500-casing, 600-premixing gas pipe;

[0025] 110-cooling hole, 120-mixing hole;

[0026] 210-swirl top plate, 220-swirl blades, 230-swirl bottom plate, 240-swirl cover plate;

[0027] 510-air inlet;

[0028] 211-annular channel, 221-fuel channel;

[0029] 2211- axial channel, 2212- radial channel. DETAILED DESCRIPTION

[0030] The following detailed description of the embodiments of the present invention is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present invention, but cannot be used to limit the scope of the present invention, that is, the present invention is not limited to the described embodiments.

[0031] In the description of the present invention, it should be noted that, unless otherwise specified, the terms "first" and "second" etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; "plurality" means two or more; the orientations or positional relationships indicated by the terms "inside", "outside", "top", "bottom" etc. are based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0032] See also Figure 1 and Figure 4The low nitrogen oxide emission combustion chamber for a gas turbine according to an embodiment of the present invention comprises a flame tube 100 and a swirl premixing section 200 arranged at a first end of the flame tube 100, wherein a main combustion stage feed pipe 300 and a pre-combustion stage feed pipe 400 are arranged on the swirl premixing section 200; the swirl premixing section 200 comprises a swirl top plate 210 and a plurality of swirl blades 220 arranged around one side of the swirl top plate 210, wherein a first end of the swirl blade 220 is connected to the swirl top plate 210. The swirl blade 220 is connected, and a fuel channel 221 is arranged inside the swirl blade 220, and the first end of the fuel channel 221 passes through the swirl top plate 210, and the second end of the fuel channel 221 extends to the second end of the swirl blade 220; the main combustion stage feed pipe 300 is arranged on the swirl top plate 210 and is connected with the first end of the fuel channel 221, and the pre-combustion stage feed pipe 400 is arranged on the swirl top plate 210 and passes through the swirl top plate 210 and extends to the area where multiple swirl blades 220 are located. In this embodiment, the pre-combustion stage feed pipe 400 and the main combustion stage feed pipe 300 share the swirl premixing section 200, and the pre-combustion stage feed pipe 400 extends to the interior of the swirl premixing section 200, and the fuel is sprayed out from the pre-combustion stage feed pipe 400, and the fuel and the air entering the swirl premixing section 200 through the gaps between the swirl blades 220 are mixed and burned. When the gas turbine reaches the specified operating condition, the fuel enters the fuel channel 221 inside the swirl blade 220 from the main combustion stage feed pipe 300, and is then sprayed out from the fuel channel 221, and the fuel and the air entering the swirl premixing section 200 through the gaps between the swirl blades 220 are mixed and burned. The trailing edge injection of the swirl blade 220 is used as the injection method of the main combustion stage fuel, so as to realize a lean premixed combustion chamber and achieve low nitrogen oxide emissions. The combustion chamber injects fuel through the trailing edge of the swirl blade 220 of the swirl premixing section 200, and has high structural reliability, is not easy to deform, is not easy to be bumped and damaged, and has stable operation.

[0033] In this embodiment, after stable combustion, the feed ratio of the main combustion stage feed pipe 300 and the pre-combustion stage feed pipe 400 can be controlled within the range of 4:1 to 10:1; the pre-combustion stage feed pipe 400 can also be completely closed, and only the main combustion stage feed pipe 300 is used to feed to maintain combustion.

[0034] Among them, the swirl blades 220 are eccentrically arranged, that is, the swirl blades 220 form an angle with the tangent of the surrounding ring, and the angle can be 15° to 65°. Due to the eccentric arrangement, the air flows through the gaps between the swirl blades 220 and then rotates to form a vortex. On the one hand, it is beneficial to enhance the mixing of air and fuel. On the other hand, a low-speed zone or even a negative-speed zone is formed in the center of the vortex, which is beneficial to combustion and flame stabilization.

[0035] In addition, the pre-combustion stage feed pipe 400 feeds less material, which plays an ignition role during combustion, ensuring that the flame does not go out and the combustion is stable.

[0036] It should be noted that the main combustion stage includes the main combustion stage fuel and air related structures; the main combustion stage is the focus of reducing nitrogen oxides. The air and most of the fuel are fully mixed in the main combustion stage structure space before burning. This can control the temperature in the entire combustion chamber at a lower level (1700K-1900K) to ensure that a large amount of nitrogen oxides will not be generated.

[0037] Lean burn refers to the ratio of the actual gas-to-air mass ratio to the gas-to-air mass ratio during complete chemical reaction (chemically appropriate). A ratio less than 1 represents lean burn, and a ratio greater than 1 represents rich burn.

[0038] As an optional embodiment, the first end of the flame tube 100 is sleeved in the casing 500, and the second end of the flame tube 100 extends to the outside of the casing 500; one end of the main combustion stage feed pipe 300 is arranged in the swirl premixing section 200, and the other end of the main combustion stage feed pipe 300 extends to the outside of the casing 500; one end of the pre-combustion stage feed pipe 400 is arranged in the swirl premixing section 200, and the other end of the pre-combustion stage feed pipe 400 extends to the outside of the casing 500.

[0039] The swirl premixing section 200 of this embodiment, as well as part of the structures of the flame tube 100, the main combustion stage feed pipe 300, and the precombustion stage feed pipe 400 are located in the casing 500, that is, the premixed combustion function is realized in the casing 500, providing an independent and enclosed space for the premixed combustion, which is beneficial to the stable operation of the combustion chamber.

[0040] As an optional embodiment, the casing 500 has an air inlet 510, and the air inlet 510 is used to provide air for combustion.

[0041] In this embodiment, air enters the casing 500 through the air inlet 510 and is mixed with the fuel in the swirl premixing section 200 , wherein the air inlet 510 may be disposed corresponding to the middle position of the flame tube 100 .

[0042] Combination Figure 2 As an optional embodiment, a cooling hole 110 is disposed at the first end of the flame tube 100 . The number of the cooling holes 110 is multiple, and the multiple cooling holes 110 are disposed axially around the flame tube 100 .

[0043] The multiple cooling holes 110 of this embodiment are arranged axially around the flame tube 100. Optionally, the multiple cooling holes 110 include multiple groups of cooling holes 110, each group of cooling holes 110 is arranged axially around the flame tube 100, and the multiple groups of cooling holes 110 are arranged along the axial direction of the flame tube 100; the multiple groups of cooling holes 110 work together to cool the flame tube 100, and the cooling is uniform, which can avoid local overheating.

[0044] Furthermore, the diameter of the cooling hole 110 may be selected to be 0.5 mm to 1.5 mm.

[0045] As an optional embodiment, mixing holes 120 are arranged on the body of the flame tube 100 , and the mixing holes 120 are arranged axially around the flame tube 100 .

[0046] The mixing holes 120 of the present embodiment are arranged on the body of the flame tube 100 , and may be located in the middle area of ​​the body of the flame tube 100 .

[0047] In this embodiment, air enters the casing 500 through the air inlet 510 and mainly enters the flame tube 100 through the cooling hole 110; air also enters the flame tube 100 through the mixing hole 120 to adjust the temperature distribution at the second end of the flame tube 100, that is, the outlet of the flame tube 100.

[0048] In addition, the diameter of the mixing holes 120 is 8 mm to 20 mm, and the number of the mixing holes 120 is 6 to 20.

[0049] Combination Figure 3 and Figure 5 As an optional embodiment, an annular channel 211 is provided on the side of the swirl top plate 210 away from the swirl blade 220, and the fuel channel 221 inside the swirl blade 220 is connected to the annular channel 211; an annular swirl cover plate 240 is provided on the side of the swirl top plate 210 away from the swirl blade 220, and the swirl cover plate 240 is arranged at the position corresponding to the annular channel 211 to seal the annular channel 211; the main combustion stage feed pipe 300 is arranged on the swirl cover plate 240 and is connected to the annular channel 211 to communicate with the fuel channel 221.

[0050] In this embodiment, when the gas turbine reaches the specified operating conditions, the fuel enters the annular channel 211 from the main combustion stage feed pipe 300, then enters the fuel channel 221 in the swirl blade 220, and is then ejected from the fuel channel 221, that is, ejected from the trailing edge of the swirl blade 220, and the fuel is mixed with the air entering from the gap between the swirl blades 220.

[0051] The annular channel 211 may be an annular groove structure, which may be directly milled out on the side of the swirl top plate 210 , and has a simple structure and is easy to form.

[0052] As an optional embodiment, the swirl premixing section 200 further includes an annular swirl bottom plate 230, and the swirl top plate 210, the swirl blades 220 and the swirl bottom plate 230 are arranged in sequence.

[0053] The swirl blades 220 of this embodiment are arranged between the swirl top plate 210 and the swirl bottom plate 230. The swirl top plate 210 receives the main combustion stage feed pipe 300 and the pre-combustion stage feed pipe 400, and the swirl bottom plate 230 receives the flame tube 100. The structure is simple and easy to assemble.

[0054] The swirl premixing unit 200 may be disposed at the first end of the flame tube 100 via the premixing gas pipe 600 ; the swirl premixing unit 200 is in communication with the flame tube 100 via the premixing gas pipe 600 .

[0055] One end of the premixed gas pipe 600 of the present embodiment is connected to the first end of the flame tube 100 , and the other end of the premixed gas pipe 600 is connected to the swirl bottom plate 230 .

[0056] In this embodiment, the fuel is sprayed out from the fuel channel 221, that is, from the trailing edge of the swirl blade 220, the fuel is mixed with the air entering from the gap between the swirl blades 220, sprayed out from the premixing pipe 600, and then burned.

[0057] As an optional embodiment, the fuel channel 221 includes an axial channel 2211 and a radial channel 2212 which are interconnected and arranged in sequence from the first end of the swirl blade 220 to the second end of the swirl blade 220, and the outlet of the radial channel is located in an inner ring of an annular ring formed by multiple swirl blades; the extension direction of the axial channel 2211 is parallel to or at an angle to the axial direction of the flame tube 100, and the extension direction of the radial channel 2212 is parallel to or at an angle to the radial direction of the flame tube 100.

[0058] In this embodiment, the fuel enters the annular channel 211 from the main combustion stage feed pipe 300, then enters the axial channel 2211 and the radial channel 2212 in the swirl blade 220, and is then ejected from the radial channel 2212, that is, ejected from the trailing edge of the swirl blade 220. The fuel is mixed with the air entering from the gap between the swirl blades 220; the outlet of the radial channel is located in the inner ring of the ring formed by multiple swirl blades, so that the mixing of fuel and air is more complete.

[0059] As an optional embodiment, there are multiple radial channels 2212 , and the multiple radial channels 2212 are arranged in sequence along the extension direction of the swirl blade 220 and can be parallel to each other. The multiple radial channels 2212 are all connected to the axial channel 2211 .

[0060] The multiple radial channels 2212 of this embodiment are evenly spaced along the extension direction of the swirl blade 220, which is conducive to the full mixing of fuel and air; and the outlet of the radial channel 2212 can be set at 1 / 5 to 4 / 5 of the extension length of the swirl blade 220.

[0061] In this embodiment, swirl blades 220 are provided on the swirl top plate 210 for fuel injection, instead of using welded nozzle-like components for fuel injection, which can effectively avoid welding deformation and easy knock damage of the fuel nozzle.

[0062] The gas turbine according to the embodiment of the present invention comprises the low nitrogen oxide emission combustion chamber for the gas turbine according to the above embodiment.

[0063] The combustion chamber of the gas turbine of this embodiment uses the trailing edge injection of the swirl blade 220 as the injection method for the main combustion stage fuel, thereby achieving lean premixed combustion, low nitrogen oxide emissions, high overall structural reliability, and stable operation.

[0064] Those skilled in the art should understand that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A low nitrogen oxide emission combustor for a gas turbine, characterized in that: It comprises a flame tube and a swirl premixing part arranged at the first end of the flame tube, wherein the swirl premixing part is provided with a main combustion stage feed pipe and a pre-combustion stage feed pipe; The swirl premixing part includes a swirl top plate and a plurality of swirl blades arranged around one side of the swirl top plate, wherein the first end of the swirl blade is connected to the swirl top plate, a fuel channel is arranged inside the swirl blade, and the first end of the fuel channel passes through the swirl top plate, and the second end of the fuel channel extends to the second end of the swirl blade; The main combustion stage feed pipe is arranged on the swirl top plate and communicated with the first end of the fuel channel, and the pre-combustion stage feed pipe is arranged on the swirl top plate and penetrates the swirl top plate and extends to the area where the multiple swirl blades are located; The fuel channel comprises an axial channel and a radial channel which are connected to each other and are arranged in sequence from the first end of the swirl blade to the second end of the swirl blade, and the outlet of the radial channel is located in the inner ring of the ring formed by the plurality of swirl blades; An annular channel is provided on one side of the swirl top plate away from the swirl blade, and the fuel channel inside the swirl blade is connected to the annular channel; The main combustion stage feed pipe is communicated with the annular channel.

2. The low nitrogen oxide emission combustor for a gas turbine according to claim 1, characterized in that: The first end of the flame tube is sleeved in the casing, and the second end of the flame tube extends outside the casing; One end of the main fuel stage feed pipe is arranged in the swirl premixing section, and the other end of the main fuel stage feed pipe extends to the outside of the casing; One end of the pre-combustion stage feed pipe is arranged in the swirl premixing section, and the other end of the pre-combustion stage feed pipe extends to the outside of the casing.

3. The low nitrogen oxide emission combustor for a gas turbine according to claim 2, characterized in that: The casing has an air inlet, and the air inlet is used to provide air for combustion.

4. The low nitrogen oxide emission combustor for a gas turbine according to claim 1, characterized in that: A cooling hole is arranged at the first end of the flame tube. There are multiple cooling holes, and the multiple cooling holes are arranged axially around the flame tube.

5. The low nitrogen oxide emission combustor for a gas turbine according to claim 1, characterized in that: The flame tube is provided with mixing holes on its body, and the mixing holes are arranged around the axial direction of the flame tube.

6. The low nitrogen oxide emission combustor for a gas turbine according to claim 1, characterized in that: A ring-shaped swirl cover plate is arranged on one side of the swirl top plate away from the swirl blades, and the swirl cover plate is arranged corresponding to the position of the annular channel to seal the annular channel; The main combustion stage feed pipe is arranged on the swirl cover plate and is communicated with the annular channel so as to be communicated with the fuel channel.

7. The low nitrogen oxide emission combustor for a gas turbine according to claim 1, characterized in that: The swirl premixing section further includes an annular swirl bottom plate, and the swirl top plate, the swirl blades and the swirl bottom plate are arranged in sequence.

8. The low nitrogen oxide emission combustor for a gas turbine according to claim 1, characterized in that: There are multiple radial channels, and the multiple radial channels are arranged in sequence along the extension direction of the swirl blades. The multiple radial channels are all connected to the axial channel.

9. A gas turbine, characterized in that: A low nitrogen oxide emission combustor for a gas turbine according to any one of claims 1 to 8.

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