Dual fuel nozzles

Abstract

The present invention provides a dual-fuel nozzle comprising a duty circuit, a main combustion circuit, and an air circuit. The main combustion circuit comprises a main oil circuit and a main gas circuit. The main oil circuit is located outside the duty circuit; the main gas circuit is located outside the main oil circuit; and the air circuit is located between the main oil circuit and the main gas circuit. This invention addresses the problems of existing turbulent diffusion combustion, which cannot form a uniform, lean, combustible gas mixture, resulting in low overall combustion efficiency and high pollutant emissions.

Description

Technical Field

[0001] The present invention relates to the technical field of gas turbines, and in particular to a dual-fuel nozzle. Background Art

[0002] A gas turbine is an internal combustion engine that uses a continuously flowing gas as a working fluid to drive a high-speed rotating impeller, converting the fuel's energy into useful work. A gas turbine typically consists of three major components: a compressor, a combustion chamber, and a turbine. The nozzle, a key component within the combustion chamber, injects fuel into the combustion chamber for combustion, releasing energy that is then transferred to the turbine for output. The performance of the nozzle directly affects the flow field structure within the combustion chamber, combustion efficiency, and flameout limit.

[0003] With the continued tightening of environmental standards, improving gas turbine combustion efficiency and reducing pollutant emissions are imperative. To reduce nitrogen oxide (NOx) emissions, lean direct injection (LDI) low-emission combustion technology has been implemented. LDI utilizes multiple injection points to inject fuel directly into the combustion zone, rapidly atomizing and mixing the fuel and air before ignition and combustion. This multi-point injection significantly increases the contact area between the fuel and air, promoting the rapid formation of a lean mixture between the fuel and air. This lowers flame temperature and eliminates local hotspots, thereby reducing NOx emissions.

[0004] However, during the turbulent diffusion combustion process, the fuel sprayed by the combustion chamber nozzle cannot form a uniform lean combustible mixture, and the overall combustion efficiency is not high, resulting in a large amount of pollutant emissions. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a dual-fuel nozzle for solving the problems that the existing turbulent diffusion combustion cannot form a uniform lean combustible mixture, has low overall combustion efficiency, and has a large amount of pollutant emissions.

[0006] To achieve the above objectives and other related objectives, the present invention provides a dual-fuel nozzle, which includes: a duty circuit, a main combustion circuit and an air circuit, wherein the main combustion circuit includes a main oil circuit and a main gas circuit.

[0007] The duty road comprises a duty pipe with a duty inlet and a duty nozzle, wherein the duty nozzle is arranged at the bottom end of the duty pipe;

[0008] The main oil circuit is arranged outside the duty circuit, and comprises a main oil pipe having a main oil inlet and at least one main oil injection hole, wherein the main oil injection hole is arranged at the bottom end of the main oil pipe;

[0009] The main gas circuit is arranged outside the main oil circuit, and includes a main gas pipe with a main gas inlet, at least one gas circuit and at least one gas circuit injection hole. The gas circuit is arranged at the bottom end of the main gas pipe and is connected to the main gas pipe. The gas circuit injection hole is arranged on the pipe wall of the gas circuit on the side close to the main oil circuit.

[0010] The air path is arranged between the main oil path and the main gas path, and includes an air pipe with an air inlet and at least one air injection hole, wherein the air injection hole is arranged at the bottom end of the air pipe.

[0011] Optionally, the main oil circuit is arranged on one side of the duty road, or the main oil circuit is arranged around the periphery of the duty road.

[0012] Optionally, the main oil circuit includes a first main oil pipe, a second main oil pipe, a first main oil inlet, a second main oil inlet, a first main oil injection hole and at least one second main oil injection hole. The first main oil pipe is arranged around the periphery of the service pipe, the first main oil inlet is arranged on the side wall of the first main oil pipe and is connected to the first main oil pipe, the first main oil injection hole is arranged at the bottom end of the first main oil pipe, the second main oil pipe is arranged on a side of the first main oil pipe away from the first main oil inlet, the second main oil inlet is arranged on the side wall of the second main oil pipe away from the first main oil pipe and is connected to the second main oil pipe, and the second main oil injection hole is arranged at the bottom end of the second main oil pipe.

[0013] Optionally, the first main oil injection hole is a gap between the first main oil pipe and the service nozzle.

[0014] Optionally, there are multiple second main oil injection holes, and the multiple second main oil injection holes are arranged around the periphery of the service nozzle and have a set distance L from the bottom end of the service nozzle, wherein L>0.

[0015] Optionally, the main air path further includes an air path groove, which is provided between the main air pipe and the air path and is communicated with the main air pipe and the air path at the same time.

[0016] Optionally, the air path groove is arranged around the duty path and the main oil path. In this case, the main air path also includes an air path groove cover, which is buckled above the part where the air path groove is not connected to the main air pipe.

[0017] Optionally, there are multiple air paths, and the multiple air paths are spaced apart and arranged at the bottom end of the air path groove; there are multiple air path injection holes, and the multiple air path injection holes are arranged in an array on the air path.

[0018] Optionally, the dual-fuel nozzle further includes: a swirler, disposed at the bottom end of the main air pipe, the swirler including at least one swirler blade, an internal pipe being provided inside the swirler blade, and the internal pipe being used to replace the air path; wherein the air path injection hole is disposed on the side of the swirler blade close to the main oil path and is connected to the internal pipe.

[0019] Optionally, the air injection hole includes a plurality of injection hole groups, and the plurality of injection hole groups are arranged around the periphery of the main oil injection hole; wherein, the injection hole group includes a radial injection hole and an axial injection hole, the radial injection hole faces the main oil injection hole and is arranged below the main oil injection hole, and the axial injection hole is arranged below the radial injection hole.

[0020] Optionally, the air path also includes: a radial airflow control structure and an axial airflow control structure, wherein the radial airflow control structure is T-shaped, one end of the T-shaped transverse part is arranged at the connection between the radial injection hole and the transverse injection hole, and the T-shaped longitudinal part is connected to the other end of its transverse part and extends downward, and forms a radial airflow outlet with the duty nozzle; the axial airflow control structure is L-shaped, one end of the L-shaped longitudinal part is arranged at the bottom end of the outer wall of the air pipe, the L-shaped transverse part is connected to the other end of its longitudinal part and extends inward, and forms an axial airflow outlet with the radial airflow control structure.

[0021] As described above, the dual-fuel nozzle of the present invention has the following beneficial effects: by introducing a duty path, combustion chamber ignition and stable combustion under wide load conditions are achieved; by introducing a main combustion path, rapid atomization and mixing of fuel and air is achieved: when burning gas, the fuel is mixed with air through multiple gas path injection holes on the swirler blades; when burning oil, the mixed fuel is injected through multiple injection holes at the end of the nozzle and mixed with air. This multi-point injection method greatly increases the contact area between the fuel and air, promoting the rapid formation of a lean fuel mixture between the fuel and air, thereby reducing flame temperature and eliminating local hot spots, thereby achieving the goal of reducing nitrogen oxide emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A cross-sectional view showing the nozzle housing and center body of the present invention

[0023] Figure 2 Shown is a cross-sectional view of a dual fuel nozzle of the present invention.

[0024] Figure 3 Shown is a bottom perspective view of some parts of the dual-fuel nozzle of the present invention.

[0025] Component number description

[0026] 1 dual fuel nozzle

[0027] 10 Duty Road

[0028] 11 Duty entrance

[0029] 12 Duty Supervisor

[0030] 13 Duty Nozzles

[0031] 14 Nut

[0032] 15 thread

[0033] 20 Main combustion line

[0034] 21 Main oil circuit

[0035] 211 Main oil inlet

[0036] 211a First main oil inlet

[0037] 211b Second main oil inlet

[0038] 212 main oil pipe

[0039] 212a First main oil pipe

[0040] 212b Second main oil pipe

[0041] 213 Main oil injection hole

[0042] 213a First main oil injection hole

[0043] 213b Second main oil injection hole

[0044] 22 Main gas line

[0045] 221 Main gas inlet

[0046] 222 main airway

[0047] 223 Gas Line

[0048] 224 gas injection hole

[0049] 225 gas channel

[0050] 226 Gas channel cover

[0051] 30 Air Line

[0052] 31 Air pipe

[0053] 32 Air Inlet

[0054] 33 air injection holes

[0055] 33a Radial injection hole

[0056] 33b Axial injection hole

[0057] 34 Radial airflow control structure

[0058] 35 Axial airflow control structure

[0059] 40 Nozzle housing

[0060] 41a First cavity

[0061] 41b Second cavity

[0062] 42 radial holes

[0063] 42a First radial hole

[0064] 42b Second radial hole

[0065] 43 connecting pipes

[0066] 44 annular positioning groove

[0067] 45 fixed steps

[0068] 45a First fixed step

[0069] 45b Second fixed step

[0070] 50 centrosomes

[0071] 51 Central cavity

[0072] 51a Upper cavity

[0073] 51b lower cavity

[0074] 52 fixed structure

[0075] 53 Boss structure

[0076] 531 Annular Gas Storage Tank

[0077] 532 slot cover

[0078] 533 through hole

[0079] 534 gas pipeline

[0080] 60 Isolation tube structure

[0081] 61 First isolation tube structure

[0082] 62 Second isolation tube structure

[0083] 63 First Gap

[0084] 64 Second Gap

[0085] 65 The Third Gap

[0086] 70 cylindrical injection structure

[0087] 71 jet hole

[0088] 80 cyclone

[0089] 81 cyclone blades

[0090] 811 Internal Pipeline

[0091] 82 fixed parts

[0092] 821 horizontal section

[0093] 822 vertical section

[0094] 823 bulge

[0095] 2 Isolation components

[0096] 2a Center hole

[0097] 2b Edge hole DETAILED DESCRIPTION

[0098] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0099] See also Figures 1 to 2 It should be noted that the illustrations provided in this embodiment are merely schematic illustrations of the basic concept of the present invention. Although the illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation, the form, quantity, and proportion of each component in actual implementation may be arbitrarily changed, and the component layout may also be more complex.

[0100] like Figure 1 As shown, this embodiment provides a dual-fuel nozzle. The dual-fuel nozzle 1 includes a service circuit 10, a main combustion circuit 20, and an air circuit 30. The main combustion circuit 20 includes a main oil circuit 21 and a main gas circuit 22. In this embodiment, the dual-fuel nozzle 1 achieves combustion chamber ignition and stable fuel combustion under a wide range of load conditions by introducing the service circuit 10. The main combustion circuit 20 also achieves rapid atomization and mixing of fuel and air, thereby achieving dual-fuel combustion of oil and gas.

[0101] Furthermore, the dual-fuel nozzle further includes a nozzle housing 40 , a center body 50 , an isolation tube structure 60 , and a tubular injection structure 70 .

[0102] Specifically, the nozzle housing 40 includes a first cavity 41a, a second cavity 41b, and a radial hole 42. The first and second cavities 41a, 41b extend through the upper and lower ends of the nozzle housing 40, with the second cavity 41b located on one side of the first cavity 41a. The first and second cavities 41a, 41b are connected via a connecting pipe 43 within the nozzle housing 40. The radial hole 42 is located on the sidewall of the nozzle housing 40, near the upper end surface of the nozzle housing 40, and includes a first radial hole 42a and a second radial hole 42b. The first radial hole 42a is connected to the first cavity 41a, while the second radial hole 42b is located on the side of the nozzle housing 40 near the second cavity 41b and is connected to the second cavity 41b. In this embodiment, the first and second radial holes 42a, 42b, and connecting pipe 43 can be formed simultaneously.

[0103] The nozzle housing 40 also includes an annular positioning groove 44 and a fixed step 45; wherein, the annular positioning groove 44 is provided on the lower end surface of the nozzle housing 40 and is connected to the second cavity 41b; the fixed step 45 is provided on the side wall close to the lower end surface of the nozzle housing 40, and includes a first fixed step 45a and a second fixed step 45b, the first fixed step 45a is provided away from the second cavity 41b, and the second fixed step 45b is provided between the first fixed step 45a and the annular positioning groove 44, and is located below the first fixed step 45a.

[0104] Specifically, the central body 50 includes a central cavity 51, a fixing structure 52 and a boss structure 53; wherein, the central cavity 51 includes an upper cavity 51a and a lower cavity 51b connected to the upper cavity 51a, and the diameter of the upper cavity 51a is larger than the diameter of the lower cavity 51b, and the central body 50 is fixedly connected to the nozzle housing 40 through the fixing structure 52 (for example, the fixing structure 52 can be fixedly connected to the nozzle housing 40 through the first fixing step 45a); the boss structure 53 is connected to the fixing structure 52, and in actual preparation The two can be integrally formed, with an annular gas storage groove 531 recessed within it above it. The annular gas storage groove ring 531 is located on the periphery of the nozzle housing 40. Furthermore, a slot cover 532 is welded to the top of the annular gas storage groove 531. The slot cover 532 has an opening reserved for connecting the main gas path. The sidewall of the boss structure 53 is provided with a plurality of spaced through holes 533. The through holes 533 are located below the annular gas storage groove 531 and connect to the central cavity 51. The through holes 533 are designed to be trumpet-shaped near the sidewall to improve the flow of gas. The boss structure is also provided with a plurality of gas pipelines 534, wherein the gas pipelines 534 are spaced apart at the lower end of the annular gas storage groove 531 and connect to the annular gas storage groove 531.

[0105] Specifically, the isolation cylinder structure 60 is placed in the central cavity 51, and includes a first isolation cylinder structure 61 and a second isolation cylinder structure 62. The first isolation cylinder structure 61 is sleeved on the periphery of the duty road 10 and fixed to the lower end of the nozzle housing 40. There is a first gap 63 between the first isolation cylinder structure 61 and the duty road 10, and the first gap 63 is connected to the first cavity 41a; the second isolation cylinder structure 62 is sleeved on the periphery of the first isolation cylinder structure 61 and fixed to the lower end of the nozzle housing 40, and there is a second gap 64 between the second isolation cylinder structure 62 and the first isolation cylinder structure 61, and the second gap 64 is connected to the second cavity 41b; at the same time, there is a third gap 65 between the second isolation cylinder structure 62 and the body wall of the central body 50. As an example, the first isolation cylinder structure 61 can be fixedly connected to the side wall of the annular positioning groove 44 close to the first cavity 41a, and the second isolation cylinder structure 62 can be fixedly connected to the vertical side wall of the second fixed step 45b.

[0106] Specifically, a plurality of injection holes 71 arranged at intervals are provided in the cylinder wall of the cylindrical injection structure 70 , and the cylindrical injection structure 70 is fixedly connected between the first isolation cylinder structure 61 and the second isolation cylinder structure 62 .

[0107] The duty road 10 includes a duty pipe 12 having a duty inlet 11 and a duty nozzle 13 . The duty inlet 11 is provided at the top end of the duty pipe 12 , and the duty nozzle 13 is provided at the bottom end of the duty pipe 12 .

[0108] In this embodiment, the service pipe 12 is inserted into the first cavity 41a of the nozzle housing 40. The top of the service pipe 12 passes through a hollow nut 14 and is fixed by a hollow thread 15 that matches the hollow nut 14, thereby fixing the service pipe 12 in the first cavity 41a. The cross-section of the nut 14 is T-shaped, and the top of the first cavity 41a reserves a space that matches the vertical portion of the nut 14. The horizontal portion of the nut 14 is placed above the nozzle housing 40, and its length is greater than the diameter of the first cavity 41a. The external device that provides fuel (oil / gas) can deliver the fuel to the service inlet 11 of the service pipe through the hollow thread 15, thereby flowing into the service path 12 and being sprayed into the combustion chamber through the service nozzle 13. The fuel at the service nozzle can undergo diffusion combustion to ensure stable combustion. The service nozzle 13 can be fixed to the bottom end of the service pipe 12 by welding.

[0109] The main oil circuit 21 is arranged outside the duty circuit 10 and includes a main oil pipe 212 having a main oil inlet 211 and at least one main oil injection hole 213 . The main oil injection hole 213 is arranged at the bottom end of the main oil pipe 211 .

[0110] In one embodiment, the main oil circuit 21 is arranged around the periphery of the service circuit 10, and includes a main oil pipe 212 having a main oil inlet 211 and a main oil injection hole 213. The main oil injection hole 213 is arranged at the bottom end of the main oil pipe 211. In this embodiment, the main oil pipe 212 is formed by the gap between the service pipe 11 and the first cavity 41a and the first gap 63 connected to the gap; the first radial hole 42a serves as the main oil inlet 211, and a hollow thread 15 is provided at the position of the first radial hole 42a by welding for connecting to the oil supply device; the end of the first isolation cylinder structure 61 away from the nozzle housing 40 is sleeved on the periphery of the upper part of the service nozzle 13, and there is a gap between the first isolation cylinder structure 61 and the service nozzle 13. The gap is the main oil injection hole 213, which is used to spray out the fuel of the main oil circuit.

[0111] In another embodiment, the main oil circuit 21 is located on one side of the duty circuit 10 and includes a main oil pipe 212 having a main oil inlet 211 and at least one main oil injection hole 213. The main oil injection hole 213 is located at the bottom end of the main oil pipe 211. In this embodiment, the main oil pipe 212 is formed by the second cavity 41b and the second gap 64, and the second cavity 41b is connected to the second gap 64. A reserved space is provided at the top of the second cavity 41b for connecting an external device. The second radial hole 42b serves as the main oil inlet 211, and a hollow thread 15 is fixed by welding at the location of the second radial hole 42b for connecting an oil supply device. The multiple injection holes 71 in the cylindrical injection structure 70 serve as the main oil injection holes 213, which are arranged at the bottom end of the main oil pipe 212, and there are multiple of them. Since the cylindrical injection structure 70 is sleeved on the periphery of the service nozzle 13 and has a set distance L from the bottom end of the service nozzle 13, where L>0, the main oil injection holes 213 are distributed above the periphery of the service nozzle 13 and are connected to the main oil pipe 212.

[0112] In a third embodiment, the main oil circuit 21 includes a first main oil pipe 212a, a second main oil pipe 212b, a first main oil inlet 211a, a second main oil inlet 211b, a first main oil injection hole 213a and at least one second main oil injection hole 213b. The first main oil pipe 212a is arranged in a ring around the periphery of the service pipe 12, the first main oil inlet 211a is arranged on the side wall of the first main oil pipe 212a and is communicated with the first main oil pipe 212a, the first main oil injection hole 213a is arranged at the bottom end of the first main oil pipe 212a, the second main oil pipe 212b is arranged on a side of the first main oil pipe 212a away from the first main oil inlet 211a, the second main oil inlet 211b is arranged on the side wall of the second main oil pipe 212b away from the first main oil pipe 212a and is communicated with the second main oil pipe 212b, and the second main oil injection hole 213b is arranged at the bottom end of the second main oil pipe 212b.

[0113] In this embodiment, the first main oil pipe 212a is formed by the gap between the service pipe 11 and the first cavity 41a, and the first gap connected to the gap. The first isolation tube structure 61 is sleeved around the periphery of the service pipe 12, one end of which is fixedly connected to the bottom end of the nozzle housing 40, and the other end is sleeved around the periphery of the service nozzle 13. A gap exists between the service nozzle 13 and the service nozzle 13. The gap is the first main oil injection hole 213a, which is used to spray the fuel in the first main oil passage 212a. The first radial hole 42a provided in the sidewall of the nozzle housing 40 serves as the first main oil inlet 211a, which is connected to the first cavity 41a. In addition, a hollow thread 15 is welded to the first main oil inlet 211a for connecting to an external device.

[0114] The second main oil pipe 212b is formed by the second cavity 41b in the nozzle housing 40 and the second gap 64 between the first isolation tube structure 61 and the second isolation tube structure 62. The second cavity 40b is connected to the second gap 64. The second isolation tube structure 64 is sleeved around the periphery of the first isolation tube structure 63, with one end fixed to the bottom end of the nozzle housing 40 and the other end fixedly connected to the cylindrical injection structure 70. The second radial hole 42b serves as the second main oil inlet 211b. A hollow thread 15 is welded to the second main oil inlet 211b for connection to an external device. The first main oil pipe 212a and the second main oil pipe 212b are connected through the connecting pipe 42 in the nozzle housing 40. The second main oil injection hole 213b is the injection hole 71 in the wall of the cylindrical injection structure 70. The cylindrical injection structure 70 is sleeved on the periphery of the service nozzle 13 and has a set distance L from the bottom end of the service nozzle 13, where L>0; since the cylindrical injection structure 70 is fixedly connected between the first isolation cylinder structure 61 and the second isolation cylinder structure 62, the multiple injection holes 71 provided in its cylinder wall are distributed above the periphery of the service nozzle 13 and are connected to the second main oil pipe 212b, which is used to spray the fuel in the second main oil pipe 212b, so that the fuel is mixed quickly to form oil-lean gas.

[0115] The main gas circuit 22 is located outside the main oil circuit 21 and includes a main gas pipe 222 having a main gas inlet 221, at least one gas channel 223, and at least one gas channel injection hole 224. The gas channel 223 is located at the bottom end of the main gas pipe 222 and communicates with the main gas pipe 222. The gas channel injection hole 224 is located on the wall of the gas channel 223 on the side closest to the main oil circuit 21. In this embodiment, the top end of the gas pipe 222 serves as the main gas inlet 221. A hollow thread 15 is welded to the main gas inlet 221 for connection to an external device that supplies fuel.

[0116] Specifically, the main gas path 22 further includes a gas path groove 225 . The gas path groove 225 is provided between the main gas pipe 222 and the gas path 223 , and is communicated with both the main gas pipe 222 and the gas path 223 .

[0117] As an example, the air path groove 225 is arranged around the duty road 10 and the periphery of the main oil road 21. At this time, the main air path 22 also includes an air path groove cover 226, which is buckled above the part where the air path groove 226 is not connected to the main air pipe 222.

[0118] In this embodiment, the annular air storage groove 531 recessed in the boss structure serves as the air path groove 225, and the groove cover 532 connected to the annular air storage groove 531 serves as the air path groove cover 226. The air path groove 225 is connected to the air path pipe 222 through the opening in the air path groove cover 226.

[0119] Specifically, there are multiple air paths 223 , which are spaced apart at the bottom of the air path groove 225 . There are multiple air path injection holes 224 , which are arranged in an array on the air path 223 .

[0120] As an example, the dual-fuel nozzle 1 also includes: a swirler 80, which is arranged at the bottom end of the main air pipe 222, and the swirler 80 includes at least one swirler blade 81, and an internal pipe 811 is provided inside the swirler blade 81, and the internal pipe 811 is used to replace the air path 223, wherein the air path injection hole 224 is close to one side of the main oil path 21 and is connected to the internal pipe 811.

[0121] In this embodiment, the swirler blade 81 is provided on the side of the boss structure 53 away from the air path groove 225, and can be integrally formed with the center body 50. The air path groove 225 is connected to the internal pipe 811 through the air path pipe 534 in the boss structure 53, wherein the air path pipe 534 and the internal pipe 811 constitute the air path 223, and the number of the air paths 223 is the same as the number of the swirler blades 81. In this embodiment, the positions of the air path pipe 534 and the air inlet 32 ​​in the boss structure 53 are staggered with each other, and the air path pipe 534 and the internal pipe 811 can be formed synchronously by drilling. The air path injection hole 224 is provided on the side of the swirler blade 81 close to the center body 50 (such as Figure 3 As shown, on one side of the triangular straight side), a plurality of gas path injection holes 224 are arranged in a hole array in the swirler blade 81.

[0122] As an example, the swirler 80 also includes a fixing component 82, wherein the fixing component 82 includes a horizontal portion 821 and a vertical portion 822 connected thereto. The horizontal portion 821 is fixedly connected to the bottom end of the swirler blade 81 via bolts, and its cross-sectional width is greater than the cross-sectional width of the swirler blade 81. This forms an annular channel with a bend in the middle between the swirler 80 and the outer wall of the center body 50, thereby making the upper end diameter of the annular channel larger than the lower end diameter. The bottom end of the vertical portion 822 is provided with a protrusion 823, which extends into the combustion chamber to fix the dual-fuel nozzle therein, thereby creating a pressure differential between the swirler blade 81 and the bottom end of the swirler 80, facilitating the entry of fuel into the combustion chamber.

[0123] The air path 30 is disposed between the main oil path 21 and the main gas path 22 , and includes an air pipe 31 having an air inlet 32 ​​and at least one air injection hole 33 . The air injection hole 33 is disposed at the bottom end of the air pipe 31 .

[0124] In this embodiment, the air pipe 31 is formed by the third gap 65 between the outer wall of the center body 50 and the second isolation tube structure 62. It is located outside the main oil circuit 21 and is coaxially arranged with the service pipe 12 and the first main oil pipe 212a. There are multiple air inlets 32, which are spaced apart and arranged on the outer wall of the center body 50 (the side wall of the air pipe) and communicate with the air pipe 31. When the center body 50 also includes a boss structure 53 connected to the fixing structure 52, the through hole 533 provided in the boss structure 53 serves as the air inlet 32 ​​and communicates with the air pipe 31.

[0125] Specifically, the air injection holes 33 include multiple injection hole groups, which are arranged around the periphery of the main oil injection hole 213. The injection hole groups include a radial injection hole 33a and an axial injection hole 33b. The radial injection hole 33a faces the main oil injection hole 213 and is located below the main oil injection hole 213. The axial injection hole 33b is located below the radial injection hole 33a. In this embodiment, the air ejected from the radial injection hole 33a is initially mixed with the fuel, while the air ejected from the axial injection hole 33b is secondarily mixed with the fuel.

[0126] Specifically, the air path 30 further includes a radial airflow control structure 34 and an axial airflow control structure 35. The radial airflow control structure 34 is T-shaped, with one end of its transverse portion located at the junction of the radial injection hole 33a and the axial injection hole 33b, and a longitudinal portion connected to the other end of the transverse portion and extending downward, forming a radial airflow outlet with the service nozzle 13. The axial airflow control structure 35 is L-shaped, with one end of its longitudinal portion located at the bottom end of the outer wall of the air tube 31, and a transverse portion connected to the other end of the longitudinal portion and extending inward, forming an axial airflow outlet with the radial airflow control structure 34. In this embodiment, the axial air path control structure 35 can be integrally formed with the center body 50.

[0127] In this embodiment, the dual-fuel nozzle 1 requires an isolation component 2 to separate and place it in air at different pressures. The isolation component 2 includes a center hole 2a and an edge hole 2b located outside the center hole 2a. When the service line 10 and the main oil line 21 are located within the nozzle housing 40, the nozzle housing 40 extends through the center hole 2a within the isolation component 2 and is secured by welding. Furthermore, the upper portion of the nozzle housing 40, including the main oil inlet 211 and the service inlet 11, is exposed to low-pressure air, while the lower portion of the nozzle housing 40 is exposed to high-pressure air. The main air pipe 222 extends through the edge hole 2b and is secured by welding. The upper portion of the main air pipe 222, including the main air inlet 221, is exposed to low-pressure air, while the lower portion of the main air pipe 222 is exposed to high-pressure air. Optionally, the isolation component 2 includes, but is not limited to, a band and a mounting flange. In this embodiment, the isolation component selected is a band.

[0128] See below Figure 1 and Figure 2 , the working process of the dual-fuel nozzle of this embodiment is explained.

[0129] The dual-fuel nozzle is divided into a main combustion path and a duty path, and its working mode is different according to the fuel (oil / gas).

[0130] When fuel is used, the service circuit introduces fuel and sprays it into the combustion chamber at the service nozzle, where it diffuses and burns, ensuring stable combustion. The main combustion circuit is the main oil circuit, which introduces fuel. Simultaneously, high-pressure air is introduced into the air inlet. Fuel is ejected through the main oil injection holes, and high-pressure air is ejected through the air injection holes. After mixing, a lean fuel-air mixture is quickly formed, which reduces flame temperature and eliminates local hot spots, ultimately reducing nitrogen oxide emissions.

[0131] When burning gas, fuel is introduced into the service path and sprayed into the combustion chamber at the service nozzle, where the fuel can undergo diffusion combustion to ensure stable combustion. The main combustion path is the main gas path. Gas is introduced into the main gas pipe, and then the gas flows into the gas path groove and fills the gas path groove. Then, it flows through the gas path pipeline into the internal pipeline inside the cyclone blades and is sprayed into the cyclone through the gas path injection hole. It is mixed with high-pressure air to form oil-lean gas. Then, under the action of the pressure inside and outside the combustion chamber, the oil-lean gas enters the combustion chamber.

[0132] In summary, the dual-fuel nozzle of the present invention can achieve combustion chamber ignition and stable combustion under wide load conditions by introducing a duty path; and can achieve rapid atomization and mixing of fuel and air by introducing a main combustion path: when burning gas, the fuel is mixed with the air through multiple gas path injection holes on the swirler blades; when burning oil, the mixed fuel is injected through multiple injection holes at the end of the nozzle and mixed with the air. The multi-point injection method greatly increases the contact area between the fuel and air, promotes the rapid formation of a lean oil mixture between the fuel and air, reduces the flame temperature and eliminates local hot spots, so as to achieve the goal of reducing nitrogen oxide emissions. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has high industrial utilization value.

[0133] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A dual fuel nozzle, characterized in that: The dual-fuel nozzle includes: a service path, a main combustion path and an air path, wherein the main combustion path includes a main oil path and a main gas path, the service path includes a service pipe with a service inlet and a service nozzle, and the service nozzle is provided at the bottom end of the service pipe; The main oil circuit is arranged outside the duty circuit, and comprises a main oil pipe having a main oil inlet and at least one main oil injection hole, wherein the main oil injection hole is arranged at the bottom end of the main oil pipe; The main gas circuit is arranged outside the main oil circuit, and includes a main gas pipe with a main gas inlet, at least one gas circuit and at least one gas circuit injection hole. The gas circuit is arranged at the bottom end of the main gas pipe and is connected to the main gas pipe. The gas circuit injection hole is arranged on the pipe wall of the gas circuit on the side close to the main oil circuit. The air path is provided between the main oil path and the main gas path, and includes an air pipe having an air inlet and at least one air injection hole, wherein the air injection hole is provided at the bottom end of the air pipe; The air injection hole includes a plurality of injection hole groups, and the plurality of injection hole groups are arranged in a ring around the periphery of the main oil injection hole; wherein the injection hole group includes a radial injection hole and an axial injection hole, the radial injection hole faces the main oil injection hole and is arranged below the main oil injection hole, and the axial injection hole is arranged below the radial injection hole; The air path further includes: a radial airflow control structure and an axial airflow control structure, wherein the radial airflow control structure is T-shaped, one end of the T-shaped transverse portion is arranged at the connection between the radial injection hole and the axial injection hole, the T-shaped longitudinal portion is connected to the other end of the transverse portion and extends downward, and forms a radial airflow outlet with the duty nozzle; the axial airflow control structure is L-shaped, one end of the L-shaped longitudinal portion is arranged at the bottom end of the outer wall of the air pipe, the L-shaped transverse portion is connected to the other end of the longitudinal portion and extends inward, and forms an axial airflow outlet with the radial airflow control structure; The main oil circuit includes a first main oil pipe, a second main oil pipe, a first main oil inlet, a second main oil inlet, a first main oil injection hole and at least one second main oil injection hole. The first main oil pipe is arranged around the outer periphery of the service pipe, the first main oil inlet is arranged on the side wall of the first main oil pipe and is connected to the first main oil pipe, the first main oil injection hole is arranged at the bottom end of the first main oil pipe, the second main oil pipe is arranged on a side of the first main oil pipe away from the first main oil inlet, the second main oil inlet is arranged on the side wall of the second main oil pipe away from the first main oil pipe and is connected to the second main oil pipe, and the second main oil injection hole is arranged at the bottom end of the second main oil pipe.

2. The dual fuel nozzle according to claim 1, characterized in that: The first main oil injection hole is a gap between the first main oil pipe and the service nozzle.

3. The dual fuel nozzle according to claim 1, characterized in that: There are multiple second main oil injection holes, and the multiple second main oil injection holes are arranged around the periphery of the service nozzle and have a set distance L from the bottom end of the service nozzle, wherein L>0.

4. The dual fuel nozzle according to claim 1, characterized in that: The main gas path further includes a gas path groove, which is provided between the main gas pipe and the gas path and is communicated with both the main gas pipe and the gas path.

5. The dual fuel nozzle according to claim 4, characterized in that: The air path groove is arranged around the periphery of the duty path and the main oil path. At this time, the main air path also includes an air path groove cover, which is buckled above the part where the air path groove is not connected to the main air pipe.

6. The dual fuel nozzle according to claim 5, characterized in that: There are multiple air paths, and the multiple air paths are spaced apart and arranged at the bottom end of the air path groove; there are multiple air path injection holes, and the multiple air path injection holes are arranged in an array on the air path.

7. The dual fuel nozzle according to any one of claims 1, 4-6, characterized in that: The dual-fuel nozzle also includes: a swirler, arranged at the bottom end of the main air pipe, the swirler including at least one swirl blade, an internal pipe is provided inside the swirl blade, and the internal pipe is used to replace the air path; wherein, the air path injection hole is arranged on the side of the swirl blade close to the main oil path and is connected to the internal pipe.

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