An axial gas-liquid dual fuel nozzle for medium and small gas turbines and its usage method

Abstract

A kind of axial gas-liquid dual-fuel nozzle for medium and small gas turbines and its usage method, belonging to the technical field of gas turbines. The present invention aims to solve the problem that medium and small gas turbines currently only apply single fuel. It includes a nozzle housing and a nozzle body. The nozzle body includes a first pipe structure, a second pipe structure, and a third pipe structure sleeved in sequence from the inside to the outside. The nozzle housing is sleeved on the outer periphery of the third pipe structure to form a central air purge path, a premixed fuel path, a diffusion fuel path, a liquid fuel path, and a main combustion air path. Orifice plates are provided at the right openings of the central air purge path, the liquid fuel path, and the premixed fuel path. A swirl vane is provided in the main combustion air path. The premixed fuel path and the main combustion air path are connected through the flow holes on a number of jet straight vanes. A number of jet straight vanes and a number of swirl vanes are arranged close to each other left and right. The present invention can achieve smooth switching between gas-liquid and liquid-gas, and has excellent comprehensive combustion performance, greatly broadening the fuel applicability of gas turbines.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas turbines, and particularly relates to an axial gas-liquid dual-fuel nozzle for a medium and small gas turbine and a usage method thereof. Background Art

[0002] Medium and small gas turbines are light in weight, can burn a variety of fuels, and have strong fuel adaptability. Therefore, they are widely used in distributed energy, industrial drive, mobile power stations, offshore drilling platforms, etc.

[0003] However, at present, medium and small gas turbines mainly burn a single gas fuel or a single liquid fuel, and cannot achieve multi-purpose use. Therefore, to a certain extent, the application range of medium and small gas turbines is limited. Summary of the Invention

[0004] The purpose of the present invention is to provide an axial gas-liquid dual-fuel nozzle for a medium and small gas turbine and a usage method thereof to solve the problem that the medium and small gas turbine currently only applies a single fuel. The technical solution adopted by the present invention is as follows:

[0005] An axial gas-liquid dual-fuel nozzle for a medium and small gas turbine includes a nozzle housing and a nozzle body. The left end of the nozzle housing is an axial air inlet in a flared shape, and the right end of the nozzle housing is connected to the flame tube body;

[0006] The nozzle body includes a first tube structure, a second tube structure, and a third tube structure sleeved in sequence from the inside to the outside. The inner cavity of the first tube structure is a central air purge path, and an orifice plate is provided at the right opening of the central air purge path. The outer periphery of the first tube structure and the inner periphery of the second tube structure are connected by an annular partition body. The partition body divides the space between the outer periphery of the first tube structure and the second tube into a premixed fuel path on the left side and a diffusion fuel path on the right side. The outer periphery of the second tube structure and the inner periphery of the third tube structure are connected by a plurality of columnar connectors. The space between the second tube structure and the third tube structure is a liquid fuel path. Orifice plates are provided at the right openings of both the liquid fuel path and the premixed fuel path. The outer periphery of the third tube structure and the inner periphery of the nozzle housing are connected by a plurality of circumferentially arranged swirl vanes. The space between the third tube structure and the nozzle housing is a main combustion air path. The inner ends of a plurality of circumferentially arranged jet straight vanes are respectively connected to the outer periphery of the second tube structure. The outer ends of the plurality of jet straight vanes respectively pass through the liquid fuel path and the third tube structure and extend into the main combustion air path. A plurality of through holes communicating the premixed fuel path and the main combustion air path are processed on each of the plurality of jet straight vanes. The plurality of jet straight vanes and the plurality of swirl vanes are arranged closely adjacent to each other left and right. The circumferential gaps between the plurality of jet straight vanes and the plurality of swirl vanes are arranged in one-to-one correspondence. A plurality of fuel inlet holes are processed along the circumference of the nozzle housing, penetrating the plurality of swirl vanes one by one, penetrating the plurality of connectors one by one, and communicating with the diffusion fuel path.

[0007] Furthermore, a first diameter-changing structure is provided in the middle of the central air purge passage, and the diameter of the right end of the central air purge passage is larger than that of the left end.

[0008] Furthermore, a second diameter-changing structure is provided in the right part of the nozzle housing, and the diameter of the right end of the nozzle housing is smaller than that of the left end.

[0009] The present invention also provides a method for using an axial gas-liquid dual-fuel nozzle for a medium and small gas turbine, which is realized based on the above-mentioned axial gas-liquid dual-fuel nozzle for a medium and small gas turbine, and includes the following steps:

[0010] Step 1: After the gas turbine starts, diffuse fuel is introduced into the diffusion fuel passage through the plurality of fuel inlet holes, and air is introduced into the liquid fuel passage.

[0011] Step 2: When the load of the gas turbine rises to 40%, premixed fuel is introduced into the premixed fuel passage, and the gaseous fuel is the sum of the diffusion fuel and the premixed fuel.

[0012] Step 3: Keep the flow rate of the introduced diffusion fuel unchanged, continue to increase the flow rate of the introduced premixed fuel. When the load of the gas turbine rises to 70%, keep the total calorific value of the introduced gaseous fuel constant, adjust the introduction ratio of the diffusion fuel to the premixed fuel, gradually increase the flow rate of the introduced premixed fuel, and gradually reduce the flow rate of the introduced diffusion fuel until the flow rate of the introduced diffusion fuel is zero, and then introduce cooling air into the diffusion fuel passage.

[0013] Step 4: When performing gas-liquid fuel switching, first adjust the load of the gas turbine to 75%, and then introduce liquid fuel into the liquid fuel passage. The flow rate of the introduced liquid fuel gradually increases. The liquid fuel is rapidly atomized under the combined action of centrifugal force, the cooling air in the diffusion fuel passage, and the swirling air in the main combustion air passage. In the high-temperature environment formed by the combustion of the gaseous fuel, the atomized liquid fuel is evaporated and gasified, and shares the air mode with the gaseous fuel to achieve gas-liquid fuel switching. Keep the total calorific value of the gaseous fuel and the liquid fuel constant, gradually reduce the flow rate of the introduced premixed fuel, and gradually increase the flow rate of the introduced liquid fuel until the flow rate of the introduced premixed fuel is zero, that is, complete the gas-liquid fuel switching.

[0014] Step 5: When performing liquid-gas fuel switching, first adjust the load of the gas turbine to 50%, then stop introducing cooling air into the diffusion fuel passage, and introduce diffusion fuel into the diffusion fuel passage again, and then gradually increase the flow rate of the introduced diffusion fuel. After the load of the gas turbine rises to 70%, keep the total calorific value of the gaseous fuel and the liquid fuel constant, gradually reduce the flow rate of the introduced liquid fuel, and gradually increase the flow rate of the introduced premixed fuel until the flow rate of the liquid fuel passage is zero, and then reintroduce cooling air into the liquid fuel passage, that is, complete the liquid-gas fuel switching.

[0015] Step 6: Keep the total calorific value of the input gas fuel constant, gradually reduce the input flow rate of the diffusion fuel, and gradually increase the input flow rate of the premixed fuel until the input flow rate of the diffusion fuel is zero. Then, re-introduce the cooling air into the diffusion fuel path, and the switching from the gas fuel diffusion mode to the premixed mode is completed.

[0016] Further, when the gas fuel and / or the liquid fuel burns, introduce air with a flow rate of 1% - 3% of the total flow rate of the diffusion fuel path and the main combustion air path into the central air purge path, push the root of the flame tube towards the combustion chamber side, and ensure that the nozzle end face temperature is within a reasonable range. Beneficial effects

[0017] The present invention provides a medium and small-sized gas turbine axial gas-liquid dual fuel nozzle, which can achieve a smooth switching between gas-liquid and liquid-gas, and has excellent comprehensive combustion performance, greatly broadening the fuel applicability of the gas turbine.

[0018] The dual fuel nozzle of the present invention has a simple structure. With the assistance of the main combustion air and the air in the diffusion fuel path, the liquid fuel can achieve good atomization. The average atomization particle size is less than 50 microns. When the load of the gas turbine is in the range of 70% - 100%, the combustion efficiency is 99.9%.

[0019] The gas fuel and the liquid fuel input into the dual fuel nozzle of the present invention share the air module, and the recirculation zones match well, enabling the co-combustion of the gas fuel and the liquid fuel. Description of the drawings

[0020] Figure 1 is a schematic structural diagram of the dual fuel nozzle of the present invention;

[0021] Figure 2 is Figure 1 the axonometric view in the direction A of

[0022] Figure 3 is Figure 1 the axonometric view in the direction B of

[0023] Figure 4 is the layout diagram of the jet straight blades and the swirl blades.

[0024] In the figure: 1 - nozzle housing, 11 - axial air inlet, 12 - second reduced diameter structure, 2 - nozzle body, 21 - first pipe structure, 22 - second pipe structure, 23 - third pipe structure, 24 - premixed fuel path, 25 - liquid fuel path, 26 - diffusion fuel path, 27 - central air purge path, 28 - main combustion air path, 29 - connection body, 3 - jet straight blade, 4 - swirl blade, 5 - flame tube body. Specific embodiments

[0025] To make the objectives, technical solutions, and advantages of the present invention more clear and understandable, the present invention will be described below through specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0026] The connections mentioned in the present invention are divided into fixed connections and detachable connections. The fixed connections, that is, non-detachable connections, include but are not limited to conventional fixed connection methods such as hemming connection, rivet connection, bonding connection, and welding connection. The detachable connections include but are not limited to conventional disassembly methods such as bolt connection, snap connection, pin connection, and hinge connection. When the specific connection method is not clearly defined, it is defaulted that at least one connection method can be found among the existing connection methods to achieve this function, and those skilled in the art can select according to their needs. For example: welding connection is selected for the fixed connection, and bolt connection is selected for the detachable connection.

[0027] The present invention will be further described in detail below in conjunction with the accompanying drawings. The following embodiments are explanations of the present invention, and the present invention is not limited to the following embodiments.

[0028] Embodiment 1: As Figures 1-4 shown, a medium and small-sized gas turbine axial gas-liquid dual-fuel nozzle includes a nozzle housing 1 and a nozzle body 2. The left end of the nozzle housing 1 is an axial air inlet 11 in the shape of a flared mouth, and the right end of the nozzle housing 1 is connected to the flame tube cylinder body 5;

[0029] The nozzle body 2 includes a first tube structure 21, a second tube structure 22, and a third tube structure 23 that are sleeved in sequence from the inside to the outside. The inner cavity of the first tube structure 21 is the central air purge passage 27. An orifice plate is provided at the right opening of the central air purge passage 27. The outer periphery of the first tube structure 21 and the inner periphery of the second tube structure 22 are connected by an annular separator. The separator divides the space between the outer periphery of the first tube structure 21 and the second tube into a premixed fuel passage 24 on the left side and a diffusion fuel passage 26 on the right side. The outer periphery of the second tube structure 22 and the inner periphery of the third tube structure 23 are connected by a plurality of columnar connectors 29. The space between the second tube structure 22 and the third tube structure 23 is the liquid fuel passage 25. Orifice plates are provided at the right openings of both the liquid fuel passage 25 and the premixed fuel passage 24. The outer periphery of the third tube structure 23 and the inner periphery of the nozzle housing 1 are connected by a plurality of circumferentially arranged swirl vanes 4. The space between the third tube structure 23 and the nozzle housing 1 is the main combustion air passage 28. The inner ends of a plurality of circumferentially arranged jet straight vanes 3 are respectively connected to the outer periphery of the second tube structure 22. The outer ends of the plurality of jet straight vanes 3 respectively pass through the liquid fuel passage 25 and the third tube structure 23 and extend into the main combustion air passage 28. A plurality of through holes communicating the premixed fuel passage 24 and the main combustion air passage 28 are machined on the plurality of jet straight vanes 3. The plurality of jet straight vanes 3 and the plurality of swirl vanes 4 are arranged adjacent to each other left and right. The circumferential gaps between the plurality of jet straight vanes 3 and the plurality of swirl vanes 4 are arranged in one-to-one correspondence. A plurality of fuel inlet holes are machined along the circumference of the nozzle housing 1, which penetrate through the plurality of swirl vanes 4 one by one, penetrate through the plurality of connectors 29 one by one, and communicate with the diffusion fuel passage 26.

[0030] A first diameter-changing structure is provided in the middle of the central air purge passage 27. The diameter of the right end of the central air purge passage 27 is larger than that of the left end.

[0031] A second diameter-changing structure 12 is provided at the right part of the nozzle housing 1. The diameter of the right end of the nozzle housing 1 is smaller than that of the left end.

[0032] Embodiment 2: A method for using an axial gas-liquid dual-fuel nozzle of a medium and small gas turbine is realized based on the axial gas-liquid dual-fuel nozzle of a medium and small gas turbine described in Embodiment 1, and includes the following steps:

[0033] Step 1: After the gas turbine is started, diffusion fuel is introduced into the diffusion fuel passage 26 through the plurality of fuel inlet holes, and air is introduced into the liquid fuel passage 25.

[0034] Step 2: When the load of the gas turbine rises to 40%, premixed fuel is introduced into the premixed fuel passage 24. The gaseous fuel is the sum of the diffusion fuel and the premixed fuel.

[0035] Step 3: Keep the input flow rate of the diffused fuel unchanged, and continue to increase the input flow rate of the premixed fuel. When the load of the gas turbine rises to 70%, keep the total calorific value of the input gas fuel constant, adjust the input ratio of the diffused fuel to the premixed fuel, gradually increase the input flow rate of the premixed fuel, and gradually reduce the input flow rate of the diffused fuel until the input flow rate of the diffused fuel is zero. Then, introduce cooling air into the diffused fuel path 26;

[0036] Step 4: When performing the gas-liquid fuel switchover, first adjust the load of the gas turbine to 75%, and then introduce liquid fuel into the liquid fuel path 25. The input flow rate of the liquid fuel gradually increases. The liquid fuel is rapidly atomized under the combined action of centrifugal force, the cooling air in the diffused fuel path 26, and the swirling air in the main combustion air path 28. In the high-temperature environment formed by the combustion of the gas fuel, the atomized liquid fuel is evaporated and gasified, and shares the air mode with the gas fuel to achieve the gas-liquid fuel switchover. Keep the total calorific value of the gas fuel and the liquid fuel constant, gradually reduce the input flow rate of the premixed fuel, and gradually increase the input flow rate of the liquid fuel until the input flow rate of the premixed fuel is zero, that is, complete the gas-liquid fuel switchover;

[0037] Step 5: When performing the liquid-gas fuel switchover, first adjust the load of the gas turbine to 50%, then stop introducing cooling air into the diffused fuel path 26, and introduce diffused fuel into the diffused fuel path 26 again. Then, gradually increase the input flow rate of the diffused fuel. After the load of the gas turbine rises to 70%, keep the total calorific value of the gas fuel and the liquid fuel constant, gradually reduce the input flow rate of the liquid fuel, and gradually increase the input flow rate of the premixed fuel until the input flow rate of the liquid fuel path is zero. Then, reintroduce cooling air into the liquid fuel path 25, that is, complete the liquid-gas fuel switchover;

[0038] Step 6: Keep the total calorific value of the input gas fuel constant, gradually reduce the input flow rate of the diffused fuel, and gradually increase the input flow rate of the premixed fuel until the input flow rate of the diffused fuel is zero. Then, reintroduce cooling air into the diffused fuel path 26, that is, complete the switchover from the diffused working condition to the premixed working condition of the gas fuel.

[0039] When the gas fuel and / or the liquid fuel burns, introduce air with a flow rate of 1% - 3% of the total flow rate of the diffused fuel path 26 and the main combustion air path 28 into the central air purge path 27, and push the root of the flame tube towards the combustion chamber side to ensure that the nozzle end face temperature is within a reasonable range.

[0040] The dual-fuel nozzle of the present invention has the following technical characteristics: For gaseous fuel, it can achieve the switching between diffused fuel and premixed fuel, ensuring stable combustion within a wide operating range and low pollutant emissions; for liquid fuel, it can utilize the assistance of the air in the main combustion air passage and the diffused fuel air passage for atomization, greatly enhancing the atomization effect of the liquid fuel, ensuring the combustion stability of the liquid fuel within a relatively large operating range, improving the combustion efficiency, and having a simple nozzle structure; the gaseous fuel and the liquid fuel share an air mold within the flame tube cylinder body 5, and the recirculation zones are well-matched, enabling the co-combustion of the gaseous fuel and the liquid fuel.

[0041] The present invention provides an axial gas-liquid dual-fuel nozzle for a medium and small gas turbine. This nozzle can achieve smooth switching between gas-liquid and liquid-gas, and has excellent comprehensive combustion performance, greatly broadening the fuel applicability of the gas turbine.

[0042] The dual-fuel nozzle of the present invention has a simple structure. With the assistance of the main combustion air and the air in the diffused fuel passage, the liquid fuel can achieve good atomization, with an average atomization particle size of less than 50 microns. When the gas turbine load is in the range of 70% - 100%, the combustion efficiency is 99.9%.

[0043] The gaseous fuel and the liquid fuel introduced into the dual-fuel nozzle of the present invention share an air mold, and the recirculation zones are well-matched, enabling the co-combustion of the gaseous fuel and the liquid fuel.

[0044] The above embodiments are only illustrative descriptions of the present invention and do not limit its protection scope. Those skilled in the art can also make partial changes to it. As long as they do not exceed the spirit of the present invention, they are within the protection scope of the present invention.

Claims

1. A medium and small-sized gas turbine axial gas-liquid dual fuel nozzle, characterized in that: The invention comprises a nozzle shell (1) and a nozzle body (2), wherein the left end of the nozzle shell (1) is a bell-shaped axial air inlet (11), and the right end of the nozzle shell (1) is connected to a flame tube body (5); the nozzle body (2) comprises a first tube structure (21), a second tube structure (22) and a third tube structure (23) which are sequentially sleeved from the inside to the outside, the inner cavity of the first tube structure (21) is a central air purge path (27), and a right opening of the central air purge path (27) is provided with a perforated plate, the outer periphery of the first tube structure (21) and the inner periphery of the second tube structure (22) are connected via an annular separator, and the separator separates the space between the outer periphery of the first tube structure (21) and the second tube into a premixed fuel path (24) located on the left and a diffusion fuel path (26) located on the right, and the outer periphery of the second tube structure (22) and the third tube structure (23) are connected. The inner periphery of the second tube structure (22) and the third tube structure (23) are connected by a plurality of columnar connectors (29); the space between the second tube structure (22) and the third tube structure (23) is a liquid fuel path (25); the right openings of the liquid fuel path (25) and the premixed fuel path (24) are both provided with orifice plates; the outer periphery of the third tube structure (23) and the inner periphery of the nozzle housing (1) are connected by a plurality of circumferentially arranged swirl blades (4); the space between the third tube structure (23) and the nozzle housing (1) is a main combustion air path (28); the inner ends of a plurality of circumferentially arranged jet straight blades (3) are respectively connected to the outer periphery of the second tube structure (22); the plurality of jet straight blades (3) are The outer ends of the nozzles (21) pass through the liquid fuel path (25) and the third tube structure (23) respectively, and extend into the main combustion air path (28). The plurality of jet straight blades (3) are processed with flow holes connecting the premixed fuel path (24) and the main combustion air path (28). The plurality of jet straight blades (3) and the plurality of swirl blades (4) are arranged close to each other on the left and right. The circumferential gaps between the plurality of jet straight blades (3) and the plurality of swirl blades (4) are arranged one by one in correspondence. A plurality of fuel inlet holes are processed along the circumference of the nozzle housing (1) and penetrate the plurality of swirl blades (4) one by one, penetrate the plurality of connectors (29) one by one, and are connected to the diffusion fuel path (26).

2. The axial gas-liquid dual-fuel nozzle for a medium and small gas turbine according to claim 1, characterized in that: A first diameter-changing structure is provided in the middle of the central air purge passage (27), and the diameter of the right end of the central air purge passage (27) is greater than the diameter of the left end.

3. A medium and small-sized gas turbine axial gas-liquid dual fuel nozzle according to claim 2, characterized in that: The right part of the nozzle housing (1) is provided with a second diameter-changing structure (12), and the diameter of the right end of the nozzle housing (1) is smaller than the diameter of the left end.

4. A method for using an axial gas-liquid dual-fuel nozzle of a medium and small gas turbine, which is realized based on the axial gas-liquid dual-fuel nozzle of a medium and small gas turbine according to any one of claims 1-3, characterized in that, The following steps are involved: Step 1: After the gas turbine is started, diffusion fuel is introduced into the diffusion fuel path (26) through the plurality of fuel inlet holes, and air is introduced into the liquid fuel path (25); Step 2: When the gas turbine load rises to 40%, premixed fuel is introduced into the premixed fuel path (24), wherein the gas fuel is the sum of the diffusion fuel and the premixed fuel; Step 3: Keep the inlet flow rate of the diffusion fuel unchanged, continue to increase the inlet flow rate of the premixed fuel. When the gas turbine load rises to 70%, keep the total calorific value of the inlet gas fuel constant, adjust the inlet ratio of the diffusion fuel to the premixed fuel, gradually increase the inlet flow rate of the premixed fuel, and gradually reduce the inlet flow rate of the diffusion fuel until the inlet flow rate of the diffusion fuel is zero. Then, introduce cooling air into the diffusion fuel path (26). Step 4: When performing the gas-liquid fuel switchover, first adjust the gas turbine load to 75%, then introduce liquid fuel into the liquid fuel path (25). The inlet flow rate of the liquid fuel gradually increases. The liquid fuel is rapidly atomized under the combined action of centrifugal force, the cooling air in the diffusion fuel path (26), and the swirling air in the main combustion air path (28). In the high-temperature environment formed by the combustion of the gas fuel, the atomized liquid fuel is evaporated and gasified, and shares the air module with the gas fuel to achieve the gas-liquid fuel switchover. Keep the total calorific value of the gas fuel and the liquid fuel constant, gradually reduce the inlet flow rate of the premixed fuel, and gradually increase the inlet flow rate of the liquid fuel until the inlet flow rate of the premixed fuel is zero, that is, complete the gas-liquid fuel switchover. Step 5: When performing the liquid-gas fuel switchover, first adjust the gas turbine load to 50%, then stop introducing cooling air into the diffusion fuel path (26), and introduce diffusion fuel into the diffusion fuel path (26) again. Then gradually increase the inlet flow rate of the diffusion fuel. After the gas turbine load rises to 70%, keep the total calorific value of the gas fuel and the liquid fuel constant, gradually reduce the inlet flow rate of the liquid fuel, and gradually increase the inlet flow rate of the premixed fuel until the inlet flow rate of the liquid fuel path is zero. Then, reintroduce cooling air into the liquid fuel path (25), that is, complete the liquid-gas fuel switchover. Step 6: Keep the total calorific value of the inlet gas fuel constant, gradually reduce the inlet flow rate of the diffusion fuel, and gradually increase the inlet flow rate of the premixed fuel until the inlet flow rate of the diffusion fuel is zero. Then, reintroduce cooling air into the diffusion fuel path (26), that is, complete the switchover from the gas fuel diffusion mode to the premixed mode.

5. A method for using an axial gas-liquid dual-fuel nozzle of a medium and small gas turbine according to claim 4, characterized in that: When the gas fuel and / or the liquid fuel burns, introduce air with a flow rate of 1% - 3% of the total flow rate of the diffusion fuel path (26) and the main combustion air path (28) into the central air purge path (27), and push the root of the flame tube towards the combustion chamber side to ensure that the nozzle end face temperature is within a reasonable range.

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