A nozzle, combustor and combustion method for hydrogen-doped combustion of a gas turbine

Abstract

The application discloses a kind of hydrogen-doped combustion nozzle, combustor and combustion method of gas turbine, it is related to hydrogen gas turbine field;Nozzle includes high-pressure air cavity, premixing chamber is arranged in high-pressure air cavity, and air inlet for high-pressure air entering is opened on high-pressure air cavity;One end of premixing chamber is provided with splitter plate, a plurality of splitter orifices for hydrogen fuel entering premixing chamber are arranged on splitter plate, a plurality of air flow channels for high-pressure air entering premixing chamber are opened on the side wall of premixing chamber, hydrogen fuel and air are mixed to form lean premixed fuel gas in premixing chamber, another end of premixing chamber is lean premixed fuel gas outlet, and mixing hole for temperature adjustment is arranged on high-pressure air cavity, lean premixed fuel gas outlet is located in mixing hole, and there is gap between the outer wall of premixing chamber and the inner wall of mixing hole.The combustor includes flame tube and nozzle, and the injection direction of the nozzle is perpendicular to the axial direction of the flame tube.The application can realize stable, low emission and safe hydrogen combustion target.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hydrogen gas turbine, in particular to a nozzle, a combustor and a combustion method for hydrogen-doped combustion of a gas turbine. BACKGROUND

[0002] To cope with global climate change and achieve the goal of reducing carbon emissions, hydrogen energy has become the most potential clean energy in the world, and many countries and regions have taken hydrogen energy as a strategic energy development. Hydrogen energy has the advantages of wide sources, high heat value and zero carbon emissions, and is a necessary choice to achieve zero-carbon clean energy. As a main power device for carbon reduction and emission reduction, gas turbine is increasingly valued, and gas turbine using hydrogen-doped or pure hydrogen combustion is an important development direction in the present and future.

[0003] The common combustion methods of gas turbine include premixed combustion and diffusion combustion. The traditional combustion system cannot meet the stability requirements of hydrogen combustion, because compared with natural gas, hydrogen has a fast flame propagation speed, a wide flammable range, a high adiabatic flame temperature, and is prone to cause backfire nozzle damage, high NOx emission, and destructive effects such as thermal acoustic oscillation. Therefore, a nozzle structure suitable for hydrogen and hydrogen-doped combustion needs to be developed to meet the demand of hydrogen-doped combustion of gas turbine combustor. SUMMARY

[0004] The purpose of the present application is to provide a nozzle, a combustor and a combustion method for hydrogen-doped combustion of a gas turbine, which can achieve stable, low-emission and safe hydrogen combustion.

[0005] The technical scheme adopted by the present application is as follows: a nozzle for hydrogen-doped combustion of a gas turbine, comprising a high-pressure air cavity, a premixing chamber is arranged in the high-pressure air cavity, and an air inlet for high-pressure air to enter is formed on the high-pressure air cavity; a splitter plate is arranged at one end of the premixing chamber, a plurality of split injection holes for hydrogen fuel to enter the premixing chamber are arranged on the splitter plate, a plurality of air flow channels for high-pressure air to enter the premixing chamber are formed on the side wall of the premixing chamber, hydrogen fuel and air are mixed in the premixing chamber to form lean premixed gas, the other end of the premixing chamber is a lean premixed gas outlet, a mixing hole for temperature adjustment is arranged on the high-pressure air cavity, the lean premixed gas outlet is located in the mixing hole, and a gap exists between the outer wall of the premixing chamber and the inner wall of the mixing hole.

[0006] Further, the fuel pipe is sealingly connected to one end of the premixing chamber.

[0007] Further, the plurality of split injection holes are uniformly distributed on the splitter plate.

[0008] Further, an angle α between an axis of the shunt nozzle and an axis of the shunt plate is 45°≤α<90°.

[0009] Further, the air flow channels are uniformly distributed.

[0010] Further, the air flow channel is a hole type structure, and an angle β between an axis of the air flow channel and a radial direction of the premixing chamber is an acute angle; or the air flow channel is a tapered groove structure, and an axis of the air flow channel is parallel to the premixing chamber, and a small opening end of the air flow channel is closer to the premixing chamber than a large opening end.

[0011] A combustor for hydrogen-doped combustion of a gas turbine, comprising a flame tube, wherein the nozzle is assembled on the flame tube, and a jet direction of the nozzle is perpendicular to an axis direction of the flame tube.

[0012] Further, one end of the flame tube is provided with a natural gas inlet, and a swirler is assembled between the natural gas inlet and the flame tube.

[0013] A combustion method for hydrogen-doped combustion of a gas turbine, applying the combustor, comprising the following steps:

[0014] S1: hydrogen fuel forms a high-speed jet through the shunt nozzle and enters the premixing chamber; high-pressure air enters the premixing chamber through the air flow channel;

[0015] S2: in the premixing chamber, the hydrogen fuel is mixed with the air to form lean premixed fuel gas;

[0016] S3: the lean premixed fuel gas enters the mixing hole to form extremely lean mixed fuel gas with the air, and the extremely lean mixed fuel gas is injected into the middle part of the flame tube;

[0017] S4: the extremely lean mixed fuel gas is ignited by high temperature in the flame tube, and the hydrogen-doped combustion of the gas turbine is completed.

[0018] Further, the shape, aperture, number and angle α of the shunt nozzle and / or the shape, aperture, number and angle β of the air flow channel are adjusted according to the mixing performance of the required air and hydrogen fuel, the flame position, shape and temperature distribution.

[0019] As described above, due to the adoption of the above technical solutions, the present application has the following beneficial effects:

[0020] The present application can make hydrogen fuel and air fully mix to form lean premixed fuel gas by means of high-speed jet of hydrogen fuel into the premixing chamber and high-pressure air into the premixing chamber, can form extremely lean mixed fuel gas by means of the premixed fuel gas into the mixing hole and air, and can effectively reduce the flame peak temperature of the flame tube, reduce the emission of NOx, and avoid high temperature and backfire, and due to the effect of the mixing hole, the premixed fuel gas can obtain greater jet depth, the hydrogen-doped combustion flame is far away from the nozzle outlet, can further effectively block backfire, and makes the combustion safer and more stable. BRIEF DESCRIPTION OF DRAWINGS

[0021] The present application will be described by way of example and with reference to the accompanying drawings, in which:

[0022] Figure 1 It is a schematic view of the structure of the burner disclosed by the present application;

[0023] Figure 2 It is a schematic view of the structure of the nozzle disclosed by the present application;

[0024] Figure 3 It is a schematic view of the top structure of the flow distribution plate disclosed by the present application;

[0025] Figure 4 It is a schematic view of the sectional structure of the flow distribution plate disclosed by the present application;

[0026] Figure 5 It is a schematic view of the first embodiment of the air flow channel disclosed by the present application;

[0027] Figure 6 It is a schematic view of the second embodiment of the air flow channel disclosed by the present application;

[0028] Marked in the figure: 1-premixing chamber; 11-air flow channel; 2-flow distribution plate; 21-flow distribution hole; 3-high-pressure air cavity; 31-mixing hole; 4-fuel pipeline; 5-flame tube; 6-natural gas inlet; 7-swirler. DETAILED DESCRIPTION

[0029] All features disclosed in this specification, and / or all steps of any methods disclosed, may be combined in any combination, except combinations where at least some of the features and / or steps are mutually exclusive.

[0030] Any feature disclosed in this specification, unless stated otherwise, can be replaced by any other feature serving the same, or a similar, purpose.

[0031] Example 1

[0032] As Figures 2-6As shown in the figure, a nozzle for hydrogen-doped combustion of a gas turbine comprises a high-pressure air cavity 3, which can be the nozzle itself disclosed in the embodiment or a structure on the gas turbine, as long as the high-pressure air cavity 3 can continuously provide high-pressure air. An air inlet for the high-pressure air is formed on the high-pressure air cavity 3, and the air inlet can be connected to an air compressor capable of providing high-pressure air.

[0033] In the embodiment, a premixing chamber 1 is arranged in the high-pressure air cavity 3. The premixing chamber 1 is in a cylindrical structure in the embodiment, and both ends thereof are not closed. One end of the premixing chamber 1 is provided with a flow dividing plate 2, which closes one end of the premixing chamber 1. A plurality of flow dividing orifices 21 are arranged on the flow dividing plate 2, and the flow dividing orifices 21 are used for the hydrogen fuel to enter the premixing chamber 1. Here, the Venturi effect occurs, and the flow rate of the input hydrogen fuel is constant. Under the same mass flow rate, the flow area is small, and the flow rate is increased, so as to ensure the total mass flow rate of the flow. Therefore, in the embodiment, the total flow area of the flow dividing orifices 21 is smaller than the flow area of the pipeline for the input hydrogen fuel, that is, the hydrogen fuel can form a high-speed jet at the flow dividing orifices 21.

[0034] In the embodiment, a plurality of air flow channels 11 are formed on the side wall of the premixing chamber 1, and the air flow channels 11 are used for the high-pressure air in the high-pressure air cavity 3 to enter the premixing chamber 1. The air flow channels 11 are arranged on the side of the premixing chamber 1, and the flow dividing orifices 21 are arranged on the flow dividing plate 2 assembled on one end of the premixing chamber 1. Therefore, the flow dividing orifices 21 and the air flow channels 11 are in a non-parallel state in space, that is, the hydrogen fuel and the high-pressure air can produce fluid impact, thereby providing a basis for mixing the hydrogen fuel and the air in the premixing chamber 1. The hydrogen fuel and the air are mixed in the premixing chamber 1 to form lean premixed fuel gas. The other end of the premixing chamber 1 is a lean premixed fuel gas outlet, and the lean premixed fuel gas in the premixing chamber 1 flows out from the lean premixed fuel gas outlet. The power for the flow out comes from the component velocity of the high-speed jet of the hydrogen fuel entering the premixing chamber 1 on the axis and the component velocity of the high-pressure air entering the premixing chamber 1 on the axis.

[0035] In the embodiment, a mixing hole 31 for temperature adjustment is arranged on the high-pressure air cavity 3. The lean premixed fuel gas flows out from the lean premixed fuel gas outlet in the premixing chamber 1 and then enters the mixing hole 31. The axis of the mixing hole 31 is collinear with the axis of the premixing chamber 1. The lean premixed fuel gas outlet is located in the mixing hole 31, and there is a gap between the outer wall of the premixing chamber 1 and the inner wall of the mixing hole 31, that is, the outer diameter of the premixing chamber 1 is smaller than the inner diameter of the mixing hole 31. The gap enables the high-pressure air to enter the mixing hole 31. The high-pressure gas in the high-pressure air cavity 3 exists in the mixing hole 31. After the lean premixed fuel gas enters the mixing hole 31, the lean premixed fuel gas is mixed with the high-pressure air at the gap again, thereby forming extremely lean premixed fuel gas.

[0036] In the embodiment, the specific implementation is as follows:

[0037] The hydrogen fuel enters the premixing chamber 1 in the form of high-speed jet, the high-pressure air enters the premixing chamber 1 through the air flow channel 11, the hydrogen fuel mixes with the high-pressure air to form lean premixed fuel gas, the lean premixed fuel gas is the fuel gas with the ratio of hydrogen fuel to air lower than the stoichiometric value of the fuel; the lean premixed fuel gas flows out of the premixing chamber 1 and enters the mixing hole 31, mixes with the high-pressure air in the mixing hole 31 to form extremely lean premixed fuel gas; the fuel stoichiometric value of the extremely lean premixed fuel gas is lower than that of the lean premixed fuel gas, so the combustion temperature of the extremely lean premixed fuel gas is lower than that of the lean premixed fuel gas, and the presence of the high-pressure air in the mixing hole 31 is equivalent to forming a barrier wall, which can effectively avoid backfire; since the fuel stoichiometric value of the extremely lean premixed fuel gas is lower, it can effectively avoid excessively high temperature, reduce the peak flame temperature in the flame tube and the emission of NOx, so that the combustion is safer, more stable and has less emission.

[0038] Embodiment 2

[0039] On the basis of embodiment 1, a specific embodiment is further proposed.

[0040] A feasible specific embodiment is that one end of the premixing chamber 1 is sealingly connected with a fuel pipeline 4, and the sealing connection avoids leakage of hydrogen fuel; the hydrogen fuel is input into the premixing chamber 1 from the fuel pipeline 4 through the flow distribution plate 2.

[0041] A feasible specific embodiment is that a plurality of flow distribution injection holes 21 are uniformly distributed on the flow distribution plate 2, which promotes uniform distribution of the hydrogen fuel in the premixing chamber 1 and improves the uniformity of mixing of the hydrogen fuel with the high-pressure air.

[0042] A feasible specific embodiment is that the flow distribution plate 2 is a perforated plate. Figures 3-4As shown, the axis of the splitter plate 2 is collinear with the axis of the premixing chamber 1, and there is an angle α between the axis of the splitter nozzle 21 and the axis of the splitter plate 2. This angle α is an acute angle formed between the vector direction of the nozzle injection and the axis of the splitter plate 2. The presence of angle α allows the high-speed jet to have a component velocity along the axis and a component velocity along the circumference. The component velocity along the axis provides momentum to push the lean premixed gas into the mixing hole 31, and the component velocity along the circumference can generate swirling flow. Swirling flow will improve the mixing degree of hydrogen fuel and high-pressure air. That is, in this embodiment, the value of the angle α is 45°≤α<90°. If the angle α is equal to 90°, the hydrogen fuel will flow along the inner wall of the nozzle, and the lean premixed gas will not receive enough transport energy, which will reduce the jet depth entering the flame tube 5. With a smaller jet depth, the hydrogen-mixed flame will approach the nozzle and backfire, which will easily burn out the nozzle. If the angle is less than 45°, the hydrogen fuel will accumulate in the axial direction, which is not conducive to mixing with high-pressure air. That is, according to actual needs, the included angle α can be adjusted within the range of 45°≤α<90° to ensure that both the required swirling intensity and the required axial velocity exist in order to meet the required jet depth.

[0043] In one feasible implementation, several air channels 11 are evenly distributed to promote uniform distribution of high-pressure air in the premixing chamber 1, thereby improving the mixing fullness and uniformity of hydrogen fuel and high-pressure air.

[0044] Specifically, in this embodiment, the following two feasible implementation methods are proposed regarding the specific structure of the "air flow channel 11".

[0045] The first implementation method, such as Figure 5 As shown, the airflow channel 11 has a perforated structure. An angle β exists between the axis of the airflow channel 11 and the radial direction of the premixing chamber 1. This angle β is acute, generating both radial and circumferential velocities within the premixing chamber 1. A larger angle β results in a larger circumferential velocity component of the air entering the premixing chamber 1, increasing the swirling intensity, but decreasing the radial velocity. In this case, the lean premixed gas cannot obtain sufficient energy to propel it, resulting in a smaller jet depth into the flame tube 5. A smaller jet depth causes the flame to approach the nozzle and backfire. Conversely, a smaller angle β results in a smaller circumferential velocity component of the air entering the premixing chamber 1, decreasing the swirling intensity and affecting the mixing degree and completeness of the hydrogen fuel and high-pressure air. In other words, the angle β can be adjusted within an acute angle range according to actual needs to ensure both the required swirling intensity and the required radial velocity, thus satisfying the required jet depth.

[0046] The second implementation method, such as Figure 6As shown, the air channel 11 has a conical groove structure. The axis of the air channel 11 is parallel to the angle between the air channel 1 and the premixing chamber 1, and the small opening end of the air channel 11 is closer to the premixing chamber 1 than the large opening end. The structure of the conical groove is simpler and easier to manufacture than the first embodiment, and can provide more high-pressure air into the premixing chamber 1.

[0047] Example 3

[0048] like Figures 1-6 As shown, a combustor for hydrogen-blended combustion in a gas turbine includes a flame tube 5. The flame tube 5 is equipped with a nozzle as described in any one of the embodiments 1-2. The nozzle injects a lean-burn mixture into the flame tube 5. The high temperature inside the flame tube 5 causes the lean-burn mixture to burn. The injection direction of the nozzle is perpendicular to the axial direction of the flame tube 5. The flame tube 5 has a large axial velocity and tangential velocity. Installing the nozzle vertically can obtain the maximum jet depth, thereby keeping the flame away from the nozzle and effectively avoiding backfire. Furthermore, the vertical installation method is beneficial for fixing the nozzle.

[0049] Furthermore, a natural gas inlet 6 is provided at one end of the flame tube 5. The combustion of natural gas in the flame tube 5 can ensure that the temperature inside the flame tube 5 reaches the combustion temperature of the lean gas mixture, so that the lean gas mixture can continue to burn. A cyclone separator 7 is installed between the natural gas inlet 6 and the flame tube 5. The cyclone separator 7 reduces the heat load of the natural gas.

[0050] Example 4

[0051] like Figures 1-6 As shown, a combustion method for hydrogen-blended combustion in a gas turbine, using the burner described in Example 3, includes the following steps:

[0052] S1: Hydrogen fuel is formed into a high-speed jet through the split nozzle 21 and enters the premixing chamber 1; high-pressure air enters the premixing chamber 1 through the air channel 11.

[0053] S2: In the premixing chamber 1, hydrogen fuel is mixed with air to form lean premixed gas;

[0054] S3: The lean premixed gas enters the mixing hole 31 and forms an extremely lean mixed gas with air, and the extremely lean mixed gas is then injected into the middle of the flame tube 5.

[0055] S4: The high temperature inside the flame tube 5 ignites the extremely lean gas mixture, completing the hydrogen-blended combustion of the gas turbine.

[0056] Furthermore, the shape, diameter, number, and angle α of the split nozzle 21 and / or the shape, diameter, number, and angle β of the airflow channel 11 can be adjusted according to the required air-hydrogen fuel mixing performance, flame position, shape, and temperature.

[0057] In the present embodiment, the more the number of jet orifices, the more the mixing uniformity with high-pressure air can be improved, but the single-hole flow rate will be reduced, thereby reducing the jet kinetic energy; the smaller the jet orifice diameter, the greater the single-hole flow rate and the jet kinetic energy; therefore, the number and diameter of the jet orifices need to be adjusted to obtain a suitable jet speed and jet depth, so that the suitable flame shape can be controlled and sustained combustion can be ensured; the change of the angle a of the jet orifice has a significant influence on the radial, circumferential and axial flow rates of the high-speed jet, different radial and axial flow rates also have a significant influence on the flame shape at the nozzle outlet, and the circumferential flow rate will affect the mixing degree and uniformity of the hydrogen fuel and high-pressure air; the number and size of the air flow channels 11 can change the mixing quality with hydrogen, and also affect the flow rate in the nozzle; the flow rate of the air entering the nozzle can also be changed, thereby changing the fuel-air ratio, which will affect the NOx emission and whether backfiring occurs, and the fuel-air ratio should be controlled to be equal to that of the extremely lean mixed gas; the change of the angle of the air flow channels 11 will mainly affect the axial and tangential flow rates in the nozzle, thereby affecting the shape of the outlet flame.

[0058] The above changes can be found through CFD combustion analysis to find the optimal parameter settings to ensure that the nozzle has sufficient jet speed, the jet medium is extremely lean mixed gas, and the extremely lean mixed gas can be sustained in the middle part of the flame tube 5 to avoid backfiring and reduce NOx emission.

[0059] The present application is not limited to the foregoing specific embodiments. The present application extends to any novel one, or any new combination, of the characteristics disclosed in this specification, as well as to any novel method or process disclosed in any of the steps or any new combination.

Claims

1. A combustor for hydrogen-doped combustion of a gas turbine, characterized by: The application relates to a hydrogen-doped combustion nozzle of a flame tube (5) and a gas turbine, the nozzle comprising a high-pressure air cavity (3) provided with a premixing chamber (1) and an air inlet for high-pressure air; one end of the premixing chamber (1) is provided with a flow distribution plate (2) provided with a plurality of flow distribution injection holes (21) for hydrogen fuel to enter the premixing chamber (1); a plurality of air flow channels (11) for high-pressure air to enter the premixing chamber (1) are formed in the side wall of the premixing chamber (1); hydrogen fuel and air are mixed in the premixing chamber (1) to form lean premixed fuel gas; the other end of the premixing chamber (1) is a lean premixed fuel gas outlet; the high-pressure air cavity (3) is provided with a mixing hole (31) for temperature adjustment; the lean premixed fuel gas outlet is located in the mixing hole (31), and a gap exists between the outer wall of the premixing chamber (1) and the inner wall of the mixing hole (31); the lean premixed fuel gas is mixed with high-pressure air in the mixing hole (31) to form extremely lean mixed fuel gas. An angle alpha exists between the axis of the flow distribution injection hole (21) and the axis of the flow distribution plate (2), and the angle alpha is 45 DEG <= alpha < 90 DEG; the axis of the flow distribution plate (2) is collinear with the axis of the premixing chamber (1). The air flow channel (11) is in a hole type structure, an angle beta exists between the axis of the air flow channel (11) and the radial direction of the premixing chamber (1), and the angle beta is an acute angle; or the air flow channel (11) is in a tapered groove structure, the axis of the air flow channel (11) is parallel to the angle of the premixing chamber (1), and the small opening end of the air flow channel (11) is closer to the premixing chamber (1) than the large opening end. The nozzle is installed on the side wall of the flame tube (5), the jet direction of the nozzle is perpendicular to the axis direction of the flame tube (5), one end of the flame tube (5) is provided with a natural gas inlet (6), natural gas enters the flame tube from the natural gas inlet (6) and is mixed with the extremely lean mixed fuel gas jetted out by the nozzle to realize hydrogen-doped combustion.

2. The burner of claim 1, wherein: One end of the premixing chamber (1) is sealingly connected with a fuel pipeline (4).

3. The burner of claim 1, wherein: The plurality of flow distribution injection holes (21) are uniformly distributed on the flow distribution plate (2).

4. Burner according to any one of claims 1-3, characterized in that: The plurality of air flow channels (11) are uniformly distributed.

5. The burner of claim 1, wherein: A swirler (7) is assembled between the natural gas inlet (6) and the flame tube (5).

6. A combustion method for hydrogen-doped combustion of a gas turbine, using the combustor according to any one of claims 1 to 5, characterized by: The application comprises the following steps: S1: hydrogen fuel forms a high-speed jet through the flow distribution injection hole (21) and enters the premixing chamber (1); high-pressure air enters the premixing chamber (1) through the air flow channel (11); S2: in the premixing chamber (1), hydrogen fuel and air are mixed to form lean premixed fuel gas; S3: the lean premixed fuel gas enters the mixing hole (31) to form extremely lean mixed fuel gas with air, and the extremely lean mixed fuel gas is jetted into the middle part of the flame tube (5); S4: the high temperature in the flame tube (5) ignites the extremely lean mixed fuel gas to complete hydrogen-doped combustion of the gas turbine.

7. The combustion method of claim 6, wherein: According to the mixing performance of air and hydrogen fuel, the flame position, the shape and the temperature distribution, the shape, the aperture, the number and the angle alpha of the flow distribution injection hole (21) are adjusted or / and the shape, the aperture, the number and the angle beta of the air flow channel (11) are adjusted.

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