A gas turbine low-emission swirl burner and operating method thereof

Abstract

The present invention discloses a low-emission swirl burner for a gas turbine and an operating method thereof. The burner comprises a hollow inner cone and an outer cone which are coaxially arranged. A plurality of swirl blades are arranged between the inner cone and the outer cone. A plurality of inner cone fuel spray hole channels penetrating the inner cone wall are arranged on the inner cone wall. An annular blade fuel spray hole channel is also arranged on the inner cone wall. A plurality of blade fuel spray holes are arranged on each swirl blade, and each blade fuel spray hole is connected to the blade fuel spray hole channel. An air channel is formed in the cavity between the inner cone and the outer cone. The fuel nozzle of the burner is designed in two stages. The first stage is the inner cone fuel spray hole channel on the inner cone wall of the burner. When the load is low, the fuel is sprayed out from the inner cavity of the inner cone through the plurality of inner cone fuel spray hole channels, which can stabilize the flame and control the emission. The other stage is the blade fuel spray hole on the swirl blade. When the load is high, the fuel is sprayed through the blade fuel spray hole, mixed with the air and burned under the action of strong swirl, which can reduce the emission of NOx.

Description

Technical Field

[0001] The invention belongs to the technical field of gas turbine combustion, and in particular relates to a gas turbine low-emission swirl burner and an operating method thereof. Background Art

[0002] As the performance parameters of gas turbines improve, gas turbines may have excessive NOx emissions at full load. In order to meet increasingly stringent emission regulations, it is necessary to design a low-emission burner suitable for gas turbines.

[0003] Chinese patent CN1280578C discloses a premix burner, which is provided with a distribution device so as to shape the air mass flow of the combustion air in the radial direction of the annular air passage, thereby generating a radially variable fuel / air mixture for stable combustion. In this patent, there is only one fuel channel, and it is impossible to realize multi-channel graded control, and the operation flexibility is relatively poor.

[0004] Chinese patent CN102345881B discloses a premixing burner for a gas turbine, in which a gap is provided between the outer peripheral end surface of the swirl blade and the inner peripheral surface of the burner tube to generate a vortex air flow through the effect of the leakage flow to promote the mixing of fuel and air. This patent also has only one fuel channel, and cannot achieve multi-channel graded control, and the operation flexibility is relatively poor.

[0005] Chinese patent CN101080596B discloses a gas turbine combustion chamber, which is designed with a control system and a separate valve to control and supply the fuel supply to each vortex blade separately, so as to meet the full load and partial load conditions of the gas turbine, and at the same time, the ratio of fuel and air near each vortex blade can be adjusted, and the requirements under different operating conditions can be met by controlling different nozzles. The control system involved in this patent is extremely complex, and each circuit needs to be controlled separately. This design project is difficult to implement and has high cost. Summary of the invention

[0006] The present invention provides a low-emission swirl burner for a gas turbine and an operating method thereof. The fuel nozzle of the burner is of a two-stage design with high operating flexibility. The first stage is an inner cone fuel spray hole channel on the inner cone wall of the burner. At low load, fuel is sprayed out from the inner cone cavity to the outside through multiple inner cone fuel spray hole channels, which can stabilize the flame and effectively control emissions. The other stage is a blade fuel spray hole on the swirl blade. At high load, fuel is sprayed through multiple blade fuel spray holes, mixed with air and burned under the action of strong swirl, which has the effect of greatly reducing NOx emissions.

[0007] The technical solution adopted by the present invention to solve its technical problem is:

[0008] A low-emission swirl burner for a gas turbine comprises a hollow inner cone and an outer cone which are coaxially arranged, a plurality of swirl blades being arranged between the inner cone and the outer cone; a plurality of inner cone fuel spray hole channels penetrating the inner cone wall are arranged on the inner cone wall, an annular blade fuel spray hole channel is also arranged on the inner cone wall, each of the swirl blades is provided with a plurality of blade fuel spray holes, and each of the blade fuel spray holes is connected to the blade fuel spray hole channel; the cavity between the inner cone and the outer cone forms an air channel.

[0009] Furthermore, the plurality of swirl blades are fixedly arranged between the small diameter end of the inner cone and the inner side surface of the outer cone.

[0010] Furthermore, the plurality of swirl blades are evenly distributed between the inner cone and the outer cone.

[0011] Furthermore, the leading edge of the swirl blade is bent and arranged on the large diameter side of the outer cone, and the trailing edge of the swirl blade is located on the small diameter side of the outer cone and is spaced a certain distance from the small diameter end of the outer cone.

[0012] Furthermore, the inner cone fuel injection hole channels are arranged in multiple rows along the axial direction of the inner cone.

[0013] Furthermore, the plurality of inner cone fuel injection hole channels in each row are evenly arranged along the circumference of the inner cone.

[0014] Furthermore, the plurality of blade fuel injection holes are distributed on both sides of the pressure surface and the suction surface of the leading edge of the swirl blade.

[0015] A method for operating a low-emission swirl burner for a gas turbine, comprising:

[0016] When the gas turbine is at low load, the fuel is sprayed out from the inner cavity of the inner cone through the plurality of inner cone fuel spray hole channels and burns with the air entering the cavity between the inner cone and the outer cone;

[0017] When the gas turbine is under high load, the fuel passes through the blade fuel injection hole channel and is ejected from each blade fuel injection hole, mixed with air to form a mixed gas, and then injected into the combustion chamber for combustion.

[0018] Furthermore, at high load, the fuel sprayed from the fuel spray holes of each blade is mixed with the air entering the cavity between the inner cone and the outer cone, and the formed mixture is swirled and sprayed into the combustion chamber for combustion.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] The low-emission swirl burner for a gas turbine of the present invention comprises a hollow inner cone and an outer cone which are coaxially arranged, a plurality of swirl blades are arranged between the inner cone and the outer cone, a plurality of inner cone fuel spray hole channels penetrating the inner cone wall are arranged on the inner cone wall, an annular blade fuel spray hole channel is also arranged on the inner cone wall, a plurality of blade fuel spray holes are arranged on each swirl blade, each blade fuel spray hole is connected to the blade fuel spray hole channel, and an air channel is formed in the cavity between the inner cone and the outer cone. The fuel nozzle of the burner is a two-stage design with high operating flexibility, and can be flexibly adjusted according to the combustion conditions of different gas turbine loads. The first stage is the inner cone fuel spray hole channel on the inner cone wall of the burner, and the fuel passes through a plurality of inner cone fuel spray hole channels at low load. The inner cone fuel spray hole channel sprays outward from the inner cone cavity and partially premixes with the air entering the cavity between the inner cone and the outer cone for combustion, which can stabilize the flame and effectively control emissions, increasing the combustion stability at low loads. The other level is the blade fuel spray hole on the swirl blade. At high loads, the fuel is sprayed through multiple blade fuel spray holes. The swirl blade can make the uniformly mixed mixture of fuel and air spray into the combustion chamber with a certain swirl intensity. Under the strong swirl effect, the fuel and air are premixed and then burned, which can improve the stability and combustion efficiency of the fuel and avoid flashback and combustion instability. This design can reduce the local concentration of the fuel, thereby reducing NOx emissions;

[0021] In the present invention, there are multiple swirl blades, and the multiple swirl blades are evenly distributed between the inner cone and the outer cone, so that the circumferential fuel concentration can be uniform, thereby controlling the emission of NOx;

[0022] In the present invention, the leading edge of the swirl blade is bent and arranged on the large diameter side of the outer cone, so that the profile of the swirl blade is a parabola, and the leading edge outlet angle of the swirl blade is large, which can ensure a certain high swirl flow, thereby improving the combustion stability;

[0023] In the present invention, the trailing edge of the swirl blade is located on the small diameter side of the outer cone and is spaced a certain distance from the small diameter end of the outer cone, which can reduce the interference between the inner and outer flames to change the delay time of the swirl burner flame, thereby improving the acoustic stability.

[0024] In summary, the swirl burner of the present invention increases the flexibility of the gas turbine under variable load, so that the unit can always maintain good low emission performance and combustion stability under different loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention.

[0026] Explanation of the reference numerals in the figure: 1. inner cone, 2. outer cone, 3. swirl blade, 4. inner cone fuel nozzle channel, 5. blade fuel nozzle channel, 6. blade fuel nozzle, 7. swirl blade leading edge, 8. swirl blade trailing edge. DETAILED DESCRIPTION

[0027] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention, but not to limit the present invention.

[0028] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] Furthermore, in the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0031] like Figure 1 As shown, a low-emission swirl burner for a gas turbine comprises a hollow inner cone 1 and an outer cone 2 which are coaxially arranged, a plurality of swirl blades 3 being fixedly arranged between the small-diameter end of the inner cone 1 and the inner side surface of the outer cone 2; a plurality of inner-cone fuel spray hole channels 4 penetrating the wall of the inner cone 1 are arranged on the wall of the inner cone 1, the inner-cone fuel spray hole channels 4 are arranged in multiple rows along the axial direction of the inner cone 1, the plurality of inner-cone fuel spray hole channels 4 in each row are evenly arranged along the circumferential direction of the inner cone 1, an annular blade fuel spray hole channel 5 is also arranged on the wall of the inner cone 1, a plurality of blade fuel spray holes 6 are arranged on each swirl blade 3, and each blade fuel spray hole 6 is connected to the blade fuel spray hole channel 5; the cavity between the inner cone 1 and the outer cone 2 forms an air channel.

[0032] Among them, multiple swirl blades 3 are evenly distributed between the inner cone 1 and the outer cone 2, and multiple blade fuel nozzles 6 are evenly distributed on both sides of the pressure surface and suction surface of the swirl blade leading edge 7, which can ensure uniform circumferential fuel concentration and thus control NOx emissions.

[0033] Among them, the leading edge 7 of the swirl blade is bent and arranged on the large diameter side of the outer cone 2, so that the profile of the swirl blade 3 is a parabola, and the outlet angle of the leading edge 7 of the swirl blade is large, which can ensure a certain high swirl, thereby improving the combustion stability.

[0034] Among them, the trailing edge 8 of the swirl blade is located on the small diameter side of the outer cone 2 and is spaced a certain distance from the small diameter end of the outer cone 2. In this way, the length of the outer cone 2 is increased, which can reduce the interference between the inner and outer flames, thereby changing the delay time of the swirl burner flame to improve the combustion stability. Under the condition of stable combustion, a smaller fuel flow rate can be tried, which can ensure that no oscillation occurs while reducing NOx emissions, thereby increasing the unit operation margin.

[0035] A method for operating a low-emission swirl burner for a gas turbine, comprising:

[0036] When the gas turbine is at low load, the fuel is ejected outward from the inner cavity of the inner cone 1 through the multiple inner cone fuel injection hole channels 4, and burns with the air entering the cavity between the inner cone 1 and the outer cone 2;

[0037] When the gas turbine is under high load, the fuel passes through the blade fuel injection hole channel 5 and is ejected from each blade fuel injection hole 6, mixing with the air entering the cavity between the inner cone 1 and the outer cone 2. The resulting mixture is swirled and injected into the combustion chamber for combustion.

[0038] The burner of the present invention supplies fuel in two ways. At low load, the fuel is sprayed out from the inner cavity of the inner cone 1 through multiple inner cone fuel spray hole channels 4, and is partially premixed and burned with the air entering the cavity between the inner cone 1 and the outer cone 2, thereby increasing the combustion stability at low load. At high load, the fuel is sprayed out through multiple blade fuel spray holes 6, and is premixed and burned with the air entering the cavity between the inner cone 1 and the outer cone 2 under the action of strong swirl. This structural design increases the flexibility of the gas turbine under variable load, so that the unit can always maintain good low emission performance and combustion stability under different loads.

[0039] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A low-emission swirl burner for a gas turbine, characterized in that: The invention comprises a hollow inner cone (1) and an outer cone (2) which are coaxially arranged, wherein a plurality of swirl blades (3) are arranged between the inner cone (1) and the outer cone (2); a plurality of inner cone fuel spray hole channels (4) which penetrate the inner cone (1) wall are arranged on the inner cone (1) wall, and an annular blade fuel spray hole channel (5) is also arranged on the inner cone (1) wall; each of the swirl blades (3) is provided with a plurality of blade fuel spray holes (6), and each of the blade fuel spray holes (6) is connected to the blade fuel spray hole channel (5); and an air channel is formed in the cavity between the inner cone (1) and the outer cone (2); The plurality of swirl blades (3) are fixedly arranged between the small diameter end of the inner cone (1) and the inner side surface of the outer cone (2); The leading edge (7) of the swirl blade is bent and arranged on the large diameter side of the outer cone (2); The trailing edge (8) of the swirl blade is located on the small diameter side of the outer cone (2) and is spaced a certain distance from the small diameter end of the outer cone (2); The plurality of blade fuel injection holes (6) are distributed on both sides of the pressure surface and the suction surface of the leading edge (7) of the swirl blade.

2. A gas turbine low emission swirl burner according to claim 1, characterized in that: The plurality of swirl blades (3) are evenly distributed between the inner cone (1) and the outer cone (2).

3. A gas turbine low emission swirl burner according to claim 1, characterized in that: The inner cone fuel injection hole channels (4) are arranged in multiple rows along the axial direction of the inner cone (1).

4. A gas turbine low emission swirl burner according to claim 3, characterized in that: The plurality of inner cone fuel injection hole channels (4) in each row are evenly arranged along the circumference of the inner cone (1).

5. The method for operating a low-emission swirl burner for a gas turbine according to any one of claims 1 to 4, characterized in that include: When the gas turbine is at low load, fuel is sprayed out from the inner cavity of the inner cone (1) through the plurality of inner cone fuel spray hole channels (4) and burns with air entering the cavity between the inner cone (1) and the outer cone (2); When the gas turbine is under high load, the fuel passes through the blade fuel injection hole channel (5) and is injected from each blade fuel injection hole (6), mixed with air to form a mixed gas, which is then injected into the combustion chamber for combustion.

6. The method for operating a low-emission swirl burner for a gas turbine according to claim 5, characterized in that: At high load, the fuel sprayed from the fuel spray holes (6) of each blade mixes with the air entering the cavity between the inner cone (1) and the outer cone (2), and the resulting mixture is swirled and sprayed into the combustion chamber for combustion.

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