A hydrogen-assisted liquid ammonia direct injection multi-stage swirl combustion chamber

Abstract

A hydrogen-assisted liquid ammonia direct-injection multi-stage swirling combustion chamber includes a fuel nozzle at the axial position, divided into a liquid ammonia nozzle and a hydrogen nozzle. A swirler is installed around the fuel nozzle, primarily composed of two stages of coaxial, oppositely rotating axial swirling blades, two stages of coaxial, oppositely rotating radial swirling blades, and four stages of guide rings for guiding compressed air. The swirler's function is to stabilize ammonia combustion. The flame tube is connected to the fourth stage guide ring of the swirler, ensuring the entry of fuel and swirling air. The flame tube has secondary air holes, mixing holes, and film cooling holes in its center to achieve secondary combustion, reduce nitrogen oxide emissions, and cool the flame tube wall. The fuel nozzle, swirler, and flame tube are enclosed within a shell, with an air guide ring between the shell and the flame tube allowing some compressed air to smoothly enter the swirler. This invention uses liquid ammonia as the main fuel, hydrogen for combustion assistance, and a multi-stage swirling process, resulting in a more stable flame and reduced nitrogen oxide emissions.

Description

Technical Field

[0001] This invention belongs to the field of thermal energy engineering technology, and relates to a combustion chamber, particularly to a hydrogen-assisted liquid ammonia direct injection multi-stage swirl combustion chamber. Background Technology

[0002] In recent years, the utilization of carbon-free fuels such as hydrogen and ammonia has received widespread attention. However, compared to hydrogen, ammonia has greater advantages as an energy carrier. Ammonia is easily liquefied, existing as a liquid at atmospheric pressure below -33°C; furthermore, due to its widespread industrial applications, ammonia has a well-established production and transportation infrastructure and can be directly used as a feedstock for power plants. However, ammonia as a fuel presents two major challenges: firstly, its low combustion rate leads to poor combustion stability and low combustion efficiency in the combustion chamber; secondly, because ammonia molecules contain nitrogen atoms, under lean combustion conditions, ammonia combustion produces extremely high NOx emissions. Current research on ammonia combustion mainly focuses on gas-phase injection of ammonia, a major drawback of which is the need for pre-evaporation of ammonia in the supply pipeline. The need for evaporation and heating prolongs the start-up time of gas turbines using gaseous ammonia mixtures as fuel. Therefore, designing a liquid ammonia combustion chamber with low NOx emissions has significant practical importance and application value in the combustion and industrial fields.

[0003] The combustion chamber is an indispensable and crucial component of a gas turbine. Under near-isobaric conditions, the combustion chamber effectively releases the chemical energy of the fuel, converting it into the thermal energy of the high-temperature combustion gas, thus preparing the conditions for its expansion and work within the gas turbine. The gas turbine combustion chamber is a combustion device typically made of high-temperature alloy materials, located within the gas turbine, between the compressor and the gas turbine.

[0004] Current combustion chambers commonly suffer from the following technical problems during operation: fuel is rapidly ignited by high-temperature air and flue gas after being injected, resulting in excessively high temperatures near the combustion chamber. Under the influence of high temperature and air, the strength of the workpiece is severely reduced, and its service life is greatly shortened; the fuel and air are not mixed evenly, resulting in incomplete combustion, low combustion efficiency, and the generation of a large amount of pollutants; the flame stability is poor, the combustion range is small, and there is even a risk of explosion; supplying gaseous ammonia to the combustion chamber requires the addition of an evaporation device to the supply pipeline, and evaporation and heating prolong the start-up time of the gas turbine. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a hydrogen-assisted liquid ammonia direct injection multi-stage swirl combustion chamber, which uses liquid ammonia as the main fuel, hydrogen as the combustion aid, and multi-stage swirl, which can make the flame more stable, reduce nitrogen oxide emissions, improve the economy of gas turbines fueled by ammonia, and shorten the start-up time.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A hydrogen-assisted liquid ammonia direct injection multi-stage swirling combustion chamber includes a swirler, a fuel injector, and a flame tube; along the fuel supply direction, the beginning of the swirler is an air inlet, and the end is connected to the flame tube.

[0008] The fuel nozzle includes a central liquid ammonia pipeline and an outer annular hydrogen pipeline. The end of the central liquid ammonia pipeline is a frustum-shaped blunt body. Liquid ammonia nozzles are provided on the top and side surfaces of the frustum-shaped blunt body. Hydrogen nozzles are provided on the end face of the outer annular hydrogen pipeline.

[0009] Both the liquid ammonia nozzle and the hydrogen nozzle are located in the swirling action area of ​​the cyclone separator, thereby forming a swirling combustion recirculation zone in the combustion chamber.

[0010] In one embodiment, the hydrocyclone includes at least an upstream axial swirling blade and a downstream radial swirling blade, with the liquid ammonia nozzle and hydrogen nozzle located between the axial swirling blade and the radial swirling blade.

[0011] In one embodiment, the axial swirling blades include at least a first-stage axial swirling blade and a second-stage axial swirling blade that are coaxial and rotate in opposite directions, and the radial swirling blades include at least a first-stage radial swirling blade and a second-stage radial swirling blade that are coaxial and rotate in opposite directions; the axial swirling blades, the radial swirling blades, and the guide ring are assembled to form the swirler.

[0012] In one embodiment, the guide ring is arranged circumferentially around the fuel nozzle and includes at least a fourth-stage guide ring, a third-stage guide ring, a second-stage guide ring, and a first-stage guide ring along the fuel supply direction; the beginning of the fourth-stage guide ring and / or the end of the first-stage guide ring are gradually expanding; the first-stage axial swirl vane and the second-stage axial swirl vane are located in the same radial direction and are assembled between the fourth-stage and third-stage guide rings; the second-stage radial swirl vane is fitted onto the third-stage guide ring, and the second-stage guide ring is installed at the end of the second-stage radial swirl vane to guide the air flowing out through it; the first-stage radial swirl vane is fitted onto the second-stage guide ring, and the first-stage guide ring is installed inside the first-stage radial swirl vane to guide the air flowing out through it.

[0013] In one embodiment, both the primary axial swirl blade and the secondary axial swirl blade are flat blades with continuously adjustable blade angles. The adjustable blade angle of the primary axial swirl blade is 35° to 45°, and the adjustable blade angle of the secondary axial swirl blade is 40° to 50°. By increasing the blade angle, the swirl combustion recirculation zone is enlarged, so that the flame is stabilized at a certain distance away from the fuel nozzle.

[0014] Both the primary and secondary radial swirl blades are flat blades. The blade angle of the primary radial swirl blade is 30° to 40°, and the blade angle of the secondary radial swirl blade is 35° to 45°. By increasing the blade angle, the swirl combustion recirculation zone is increased, so that the flame is stabilized at a certain distance away from the fuel nozzle.

[0015] In one embodiment, the hydrogen nozzles are circumferentially and uniformly arranged outside the liquid ammonia nozzles, and by volume, the liquid ammonia provided by the liquid ammonia nozzles and the hydrogen provided by the hydrogen nozzles satisfy a hydrogen doping ratio of 2%-5%.

[0016] In one embodiment, the bottom surface of the frustum-shaped blunt body is flush with the end face of the outer annular hydrogen pipeline, and the liquid ammonia nozzles located on the side of the blunt body are distributed in multiple rings along the axial direction, with the spray direction forming an angle of 55° to 65° with the axial direction.

[0017] In one embodiment, the flame tube wall is provided with mixing holes, secondary air holes, and film cooling holes; along the fuel supply direction, the secondary air holes are located upstream of the mixing holes and are used to supply air to the flame tube to achieve secondary combustion of ammonia; the mixing holes are used to supply air to the flame tube to dilute the burned fuel; the film cooling holes are used to form a cooling film protective layer on the surface of the tube wall; along the fuel supply direction, the flame tube consists of a gradually expanding section, a long cylindrical section, and a gradually contracting section, and the mixing holes, secondary air holes, and film cooling holes are provided on the tube wall of the long cylindrical section.

[0018] In one embodiment, the invention further includes a combustion chamber shell and an air guide ring. The combustion chamber shell surrounds the swirler, fuel injector, flame tube, and air guide ring, and has a fuel injector inlet, a compressed air inlet, and a flue gas outlet. The air guide ring is disposed between the inner wall of the combustion chamber shell and the outer wall of the flame tube, separating the compressed air inlet from the beginning of the swirler. The air guide ring is fitted at the junction of the expanding section and the elongated cylindrical section of the flame tube, and is tapered along the fuel supply direction, with uniformly spaced openings in its circumference to allow compressed air to flow smoothly.

[0019] In one embodiment, the fuel nozzle is configured to move axially along the burner to adjust the moving distance according to different operating conditions. When injecting a large flow of liquid ammonia, it moves away from the flame tube to ensure sufficient mixing of fuel and air and promote stable combustion of liquid ammonia.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. This combustion chamber uses liquid ammonia as fuel, which improves fuel economy and shortens the start-up time of the gas turbine compared to gaseous ammonia, and produces no carbon dioxide after combustion. Simultaneously, the addition of a small amount of axial hydrogen promotes complete fuel combustion, resulting in a more stable flame and preventing dangerous situations such as flameout and backfire.

[0022] 2. This combustion chamber can precisely adjust the fuel-air ratio by separately controlling the supplied hydrogen, liquid ammonia, and air. At the same time, by designing two-stage axial swirl blades and two-stage radial swirl blades, it is beneficial to form a larger recirculation zone, which allows the thermal products and active free radicals in the downstream of the combustion chamber to flow back to the upstream. On the one hand, it preheats the mixture, and on the other hand, it increases the residence time of the fluid in the combustion chamber, making the combustion more complete and improving the combustion efficiency.

[0023] 3. This combustion chamber achieves staged combustion through flame tube openings, allowing for rich combustion at the bottom of the chamber. Unburned ammonia then undergoes secondary combustion with air entering through the secondary air vents in the middle of the chamber. Furthermore, the nitrogen oxides produced after combustion are diluted by air entering through the mixing vents, resulting in ultra-low pollutant emissions. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a liquid ammonia direct injection multi-stage swirl combustion chamber.

[0025] Figure 2 This is a cross-sectional view of a liquid ammonia direct injection multi-stage swirl combustion chamber.

[0026] Figure 3 This is a diagram of the fuel nozzle structure.

[0027] Figure 4 It is a cross-sectional view of the fuel nozzle and cyclone separator structure.

[0028] Figure 5 This is a cross-sectional view of a first-stage radial swirl blade.

[0029] Figure 6 This is a cross-sectional view of the secondary radial swirl blade.

[0030] Figure 7 This is a cross-sectional view of a first-stage axial swirl blade.

[0031] Figure 8 This is a cross-sectional view of the secondary axial swirl blade. Detailed Implementation

[0032] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings and examples.

[0033] like Figure 1 , Figure 2 and Figure 3As shown, this invention is a hydrogen-assisted liquid ammonia direct injection multi-stage swirling combustion chamber, mainly comprising a swirler, a fuel nozzle 2, and a flame tube 3. Along the fuel supply direction, the beginning of the swirler is the air inlet, and its end connects to the flame tube 3. Using liquid ammonia as fuel with a small amount of hydrogen for combustion assistance promotes complete combustion of ammonia while preventing carbon dioxide generation.

[0034] The fuel injector 2 includes a central liquid ammonia line and an outer annular hydrogen line. The main axial directions of both the central liquid ammonia line and the outer annular hydrogen line are the same as the combustion chamber axis. The two lines should preferably be coaxial, with the central liquid ammonia line in the center and the outer annular hydrogen line surrounding it. The end of the central liquid ammonia line is a frustum-shaped blunt body, with liquid ammonia nozzles 21 arranged on the top and sides of the blunt body. The end face of the outer annular hydrogen line is provided with hydrogen nozzles 22.

[0035] Both the liquid ammonia nozzle 21 and the hydrogen nozzle 22 are located in the swirling action area of ​​the cyclone separator, thereby forming a swirling combustion recirculation zone in the combustion chamber.

[0036] According to the present invention, liquid ammonia is the main fuel, while hydrogen is the combustion-supporting fuel. Specifically, the flow rate of liquid ammonia supplied by the liquid ammonia nozzle 21 is much greater than that of hydrogen supplied by the hydrogen nozzle 22. Compared to gaseous ammonia, this improves economic efficiency, shortens the start-up time of the gas turbine, and produces no carbon dioxide after combustion. Simultaneously, the addition of a small amount of axial hydrogen promotes complete combustion of the fuel, making the flame more stable and preventing dangerous situations such as flameout and backfire.

[0037] Furthermore, since the liquid ammonia pipeline of this invention is located in the center, while the hydrogen pipeline is arranged around the liquid ammonia pipeline, the main fuel liquid ammonia is injected from the axial position, and the fuel nozzles are all located in the swirling action area of ​​the cyclone separator. Therefore, the residence time of the fluid in the combustion chamber can be increased, making the combustion more complete and improving the combustion efficiency.

[0038] In some embodiments of the present invention, the hydrocyclone includes at least an upstream axial swirling blade and a downstream radial swirling blade, in which case the liquid ammonia nozzle 21 and the hydrogen nozzle 22 are both located between the upstream axial swirling blade and the downstream radial swirling blade.

[0039] In this embodiment, the axial swirl vane is located upstream, while the swirl vane is located downstream. Both the liquid ammonia nozzle 21 and the hydrogen nozzle 22 are situated between them, within a clearly defined swirl zone, ensuring the formation of a swirl combustion recirculation zone within the combustion chamber. The axial and radial swirl of air significantly improves combustion stability.

[0040] In some embodiments of the present invention, reference is made to Figure 4The axial swirling blades include at least a primary axial swirling blade 16 and a secondary axial swirling blade 17, which are coaxially assembled and rotate in opposite directions. For example, the primary axial swirling blade 16 is located outside the secondary axial swirling blade 17. The radial swirling blades include at least a primary radial swirling blade 13 and a secondary radial swirling blade 14, which are coaxially assembled and rotate in opposite directions. For example, the secondary radial swirling blade 14 is located upstream of the primary radial swirling blade 13. This invention constructs a swirling device by assembling axial swirling blades, radial swirling blades, and a guide ring.

[0041] In this embodiment, on the one hand, by controlling the supplied hydrogen, liquid ammonia and air separately, the ratio of fuel to air can be precisely adjusted. The air enters the combustion chamber through two-stage axial swirl blades, which is conducive to forming a larger recirculation zone. It interacts with the liquid ammonia sprayed from the liquid ammonia nozzle 21, so that the thermal products and active free radicals in the downstream of the combustion chamber flow back to the upstream. This can not only preheat the mixture, but also further increase the residence time of the fluid in the combustion chamber and improve the combustion stability.

[0042] Furthermore, the guide ring of the present invention is arranged around the circumferential periphery of the fuel nozzle 2, and obviously has an air passage between it and the outer diameter of the fuel nozzle 2. In embodiments of the present invention, it includes at least a fourth-stage guide ring 18, a third-stage guide ring 15, a second-stage guide ring 12, and a first-stage guide ring 11 along the fuel supply direction. The beginning of the fourth-stage guide ring 18 and / or the end of the first-stage guide ring 11 can be configured to be gradually expanding. The first-stage axial swirl vane 16 and the second-stage axial swirl vane 17 are located in the same radial direction and are assembled between the fourth-stage guide ring 18 and the third-stage guide ring 15. In specific applications, they can be fitted onto the outer wall of the fuel nozzle 2. The fourth-stage guide ring 18 and the third-stage guide ring 15 are used to guide air into and out of the axial swirl vane, respectively. A secondary radial swirl blade 14 is fitted onto a tertiary guide ring 15. A secondary guide ring 12 is installed at the end of the secondary radial swirl blade 14 to guide the air flowing out through it. A primary radial swirl blade 13 is fitted onto the secondary guide ring 12. A primary guide ring 11 is installed inside the primary radial swirl blade 13 to guide the air flowing out through it. That is, in this embodiment, the swirler is coaxially assembled with a primary guide ring 11, a secondary guide ring 12, a primary radial swirl blade 13, a secondary radial swirl blade 14, a tertiary guide ring 15, a primary axial swirl blade 16, a secondary axial swirl blade 17, and a quaternary guide ring 18. The four guide rings are used to guide the compressed air, and the overall function of the swirler is to stabilize the combustion of ammonia.

[0043] In this embodiment, the incoming air can freely enter the first-stage axial swirl vane 16, the second-stage axial swirl vane 17, the first-stage radial swirl vane 13, and the second-stage radial swirl vane 14, and then enter the combustion chamber through the corresponding air guide rings. Because the air generates tangential and radial velocities after passing through the swirl vanes, a recirculation zone is formed within the combustion chamber, returning the downstream thermal products and active free radicals to the upstream. This preheats the fresh mixture and increases the residence time of the fluid within the combustion chamber, thereby improving the stability of ammonia combustion and further enhancing thermal efficiency.

[0044] In some embodiments of the present invention, reference is made to Figure 5 , Figure 6 , Figure 7 and Figure 8 Both the first-stage axial swirl blade 16 and the second-stage axial swirl blade 17 are flat blades with continuously adjustable blade angles. The adjustable range of the blade angle for the first-stage axial swirl blade 16 is 35° to 45°, and the adjustable range for the blade angle for the second-stage axial swirl blade 17 is 40° to 50°. By increasing the blade angle, the swirl combustion recirculation zone is enlarged, which allows the flame to be stabilized at a certain distance away from the fuel nozzle 2. Here, the axial swirl blade angle refers to the acute angle formed by the blade's tilt direction and the axial direction.

[0045] Accordingly, both the first-stage radial swirl blade 13 and the second-stage radial swirl blade 14 are flat blades. The blade angle of the first-stage radial swirl blade 13 is 30° to 40°, and the blade angle of the second-stage radial swirl blade 14 is 35° to 45°. By increasing the blade angle, the swirl combustion recirculation zone is enlarged, which allows the flame to be stabilized at a certain distance away from the fuel nozzle 2. Here, the radial swirl blade angle refers to the acute angle formed by the blade's tilt direction and the radial direction. Furthermore, along the reverse fuel supply direction, the swirl direction of the first-stage axial swirl blade 16 and the first-stage radial swirl blade 13 is clockwise, while the swirl direction of the second-stage axial swirl blade 17 and the second-stage radial swirl blade 14 is counterclockwise, as shown below. Figures 5 to 8 As shown. Among them, as Figures 5 to 8 The proportions are the same, that is, it exemplifies the size comparison of each swirl blade.

[0046] In this embodiment, the angle between the secondary swirl blade and the axis should be slightly greater than the angle between the primary swirl blade and the axis. By adjusting the blade angle, the size of the swirl combustion recirculation zone is controlled, so that the flame is stabilized at a certain distance away from the fuel nozzle 2. This can effectively stabilize the flame of the primary combustion, while preventing the double swirl blades from being ablated and extending their service life.

[0047] In some embodiments of the present invention, the hydrogen nozzle 22 is circumferentially and uniformly arranged outside the liquid ammonia nozzle 21, and the liquid ammonia provided by the liquid ammonia nozzle 21 and the hydrogen provided by the hydrogen nozzle 22 satisfy a hydrogen doping ratio of 2%-5% by volume.

[0048] In some embodiments of the present invention, the bottom surface of the frustum-shaped blunt body is flush with the end face of the outer annular hydrogen pipeline, and the liquid ammonia nozzles 21 located on the side of the blunt body are distributed in multiple rings along the axial direction, and the spraying direction is at an angle of 55° to 65° with the axial direction.

[0049] In this embodiment, liquid ammonia is ejected from the liquid ammonia nozzle 21 through the central pipeline. The liquid ammonia ejected from the side of the truncated cone has an angle of 55° to 65° with the axial direction of the fuel nozzle 2, as described above, and interacts with the air entering through the cyclone separator. The liquid ammonia ejected from the top of the truncated cone is parallel to the axial direction of the fuel nozzle 2, and hydrogen is ejected from the hydrogen nozzle 22 through the outer pipeline, which is parallel to the axial direction of the fuel nozzle 2.

[0050] For example, in a specific project, the diameter of the liquid ammonia nozzle 21 at the top of the truncated cone is larger, while the diameter of the liquid ammonia nozzle 21 on the side of the truncated cone is smaller. Figure 3 In the embodiment shown, the liquid ammonia nozzles 21 on the side of the frustum are arranged in two rings, with four nozzles in each ring. The diameter of each hydrogen nozzle 22 is uniform, and the opening positions are on the same plane, totaling 12 nozzles, which are used to pass hydrogen to achieve liquid ammonia combustion and improve combustion efficiency.

[0051] In some embodiments of the present invention, the flame tube 3 is provided with mixing holes 31, secondary air holes 32, and film cooling holes 33 on its wall. Along the fuel supply direction, the secondary air holes 32 are located upstream of the mixing holes 31 and are used to supply air to the flame tube 3, enabling secondary combustion of ammonia and reducing nitrogen oxide generation. The mixing holes 31 are used to supply fresh air to the flame tube 3, which can dilute the burned fuel and further reduce nitrogen oxide emissions. The film cooling holes 33 are used to form a cooling film protective layer on the surface of the tube wall. Along the fuel supply direction, the flame tube 3 consists of a gradually expanding section, a long cylindrical section, and a gradually contracting section. Its initial end fits onto the primary guide ring 11, with the fitting part being the gradually expanding section. Then, along the flow direction, the middle part is a long cylindrical section, and the end is a gradually contracting section. This stabilizes the flame and facilitates the discharge of pollutants after combustion. The mixing holes 31, secondary air holes 32, and film cooling holes 33 are provided on the wall of the long cylindrical section. Specifically, two rings of holes are formed in the middle of the long cylindrical section. The first ring has six smaller secondary air holes 32 along the flow direction to allow secondary air to enter and achieve secondary combustion, reducing nitrogen oxide generation. The second ring has six larger mixing holes 31, mainly used to allow fresh air to dilute the combustible gas and further reduce emissions. Between every two secondary air holes 32 or mixing holes 31, ten smaller gas film cooling holes 33 are formed to create a gas film, which cools the wall of the flame tube 3, preventing the flame tube 3 from becoming too hot and extending its service life.

[0052] In this embodiment, one end of the flame tube 3 is fitted onto the four-stage guide ring 18 of the cyclone separator, ensuring the entry of fuel and swirling air, thus providing space for fuel and air combustion. Through openings on the flame tube 3, staged combustion can be achieved, with rich combustion at the bottom of the combustion chamber, while unburned ammonia undergoes secondary combustion with air entering through the secondary air hole 32 in the middle of the combustion chamber. Furthermore, the nitrogen oxides after combustion are diluted by air entering through the mixing hole 31, thereby achieving ultra-low pollutant emissions. The multi-stage combustion achieved in this embodiment can significantly reduce the generation and emission of nitrogen oxides.

[0053] In some embodiments of the present invention, the liquid ammonia direct injection multi-stage swirling combustor of the present invention further includes a combustor shell 5 and an air guide ring 4, wherein the swirler, fuel injector 2, flame tube 3, and air guide ring 4 can be coaxially arranged. The combustor shell 5 surrounds the swirler, fuel injector 2, flame tube 3, and air guide ring 4, and has a fuel injector 2 inlet, a compressed air inlet 51, and a flue gas outlet. For example, the fuel injector 2 inlet is at the bottom, the compressed air inlet 51 is on the side, and the flue gas outlet is at the top of the shell. The air guide ring 4 is disposed between the inner wall of the combustor shell 5 and the outer wall of the flame tube 3, separating the compressed air inlet 51 from the beginning of the swirler, that is, the combustor shell 5 and the flame tube 3 are connected by the air guide ring 4. The air guide ring 4 fits at the junction of the expanding section and the elongated cylindrical section of the flame tube 3, and is tapered along the fuel supply direction, with uniformly spaced holes (defined as guide holes) in its circumference to allow compressed air to flow smoothly. For example, the number of holes is 8.

[0054] In this embodiment, compressed air enters the combustion chamber shell 5 through the compressed air inlet 51, and then flows to the air guide ring 4 and the flame tube 3 respectively. The compressed air entering the air guide ring 4 is delivered to the cyclone separator through the guide holes provided on the air guide ring 4.

[0055] In some embodiments of the present invention, the fuel nozzle 2 is configured to move along the burner axis, so that the moving distance can be adjusted according to different operating conditions. When injecting a large flow of liquid ammonia, it moves away from the flame tube 3 to ensure sufficient mixing of fuel and air and promote stable combustion of liquid ammonia.

[0056] In summary, this invention achieves a more stable flame, reduces nitrogen oxide emissions, improves the economy of ammonia-fueled gas turbines, and shortens start-up time by using liquid ammonia as the main fuel and hydrogen as the combustion aid, through multi-stage swirl.

[0057] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope disclosed in the present invention, based on the technical solution and inventive concept of the present invention, shall fall within the scope of protection of the present invention.

Claims

1. A hydrogen-fueled liquid ammonia direct-injection multistage swirled combustion chamber, characterized by, It comprises a swirler, a fuel nozzle (2), a flame tube (3), an air guide ring (4) and a combustion chamber shell (5); along the fuel supply direction, the initial end of the swirler is an air inlet end, and the terminal end is connected to the flame tube (3); The fuel nozzle (2) comprises a central liquid ammonia pipeline and an outer annular hydrogen pipeline, the terminal end of the central liquid ammonia pipeline is a circular truncated cone-shaped blunt body, the top surface and the side surface of the circular truncated cone-shaped blunt body are provided with liquid ammonia nozzles (21), and the terminal end surface of the outer annular hydrogen pipeline is provided with hydrogen nozzles (22); the bottom surface of the circular truncated cone-shaped blunt body is flush with the terminal end surface of the outer annular hydrogen pipeline, the liquid ammonia nozzles (21) on the side surface of the blunt body are distributed in multiple circles along the axial direction, and the jet direction forms an angle of 55° to 65° with the axial direction; The liquid ammonia nozzles (21) and the hydrogen nozzles (22) are located in the swirling action area of the swirler, so as to form a swirling combustion backflow area in the combustion chamber; The swirler at least comprises upstream axial swirling vanes and downstream radial swirling vanes, and the liquid ammonia nozzles (21) and the hydrogen nozzles (22) are located between the axial swirling vanes and the radial swirling vanes; The combustion chamber shell (5) surrounds the swirler, the fuel nozzle (2), the flame tube (3) and the air guide ring (4), and leaves a fuel nozzle (2) inlet, a compressed air inlet (51) and a flue gas outlet; the air guide ring (4) is arranged between the inner wall of the combustion chamber shell (5) and the outer wall of the flame tube (3), separates the compressed air inlet (51) and the initial end of the swirler, and is matched with the connection between the gradually expanding section and the long cylindrical section of the flame tube (3), and is tapered along the fuel supply direction, and is uniformly perforated in the circumferential direction to enable the compressed air to flow smoothly.

2. The hydrogen-facilitated liquid ammonia direct injection multistage swirl combustor of claim 1, wherein, The axial swirling vanes at least comprise coaxial and opposite-rotation first and second axial swirling vanes (16 and 17), and the radial swirling vanes at least comprise coaxial and opposite-rotation first and second radial swirling vanes (13 and 14); the axial swirling vanes, the radial swirling vanes and the guide ring are assembled to form the swirler.

3. The hydrogen-facilitated liquid ammonia direct injection multistage swirl combustor of claim 2, wherein, The guide ring is arranged on the circumferential periphery of the fuel nozzle (2) and at least comprises four-stage guide rings (18), three-stage guide rings (15), two-stage guide rings (12) and one-stage guide rings (11) along the fuel supply direction; the initial end of the four-stage guide ring (18) and / or the terminal end of the one-stage guide ring (11) is tapered, the first axial swirling vanes (16) and the second axial swirling vanes (17) are located in the same radial direction and are assembled between the four-stage guide ring (18) and the three-stage guide ring (15); the second radial swirling vanes (14) are matched on the three-stage guide ring (15), the two-stage guide ring (12) is installed at the terminal end of the second radial swirling vanes (14) to guide the air flowing out through the two-stage guide ring (12); the first radial swirling vanes (13) are matched on the two-stage guide ring (12), and the one-stage guide ring (11) is installed on the inner side of the first radial swirling vanes (13) to guide the air flowing out through the one-stage guide ring (11).

4. The hydrogen-facilitated liquid ammonia direct injection multistage swirl combustor of claim 2, wherein, The first and second axial swirl vanes (16, 17) are flat vanes, and the vane angle is continuously adjustable, the vane angle of the first axial swirl vane (16) is adjustable in the range of 35° to 45°, and the vane angle of the second axial swirl vane (17) is adjustable in the range of 40° to 50°, the swirl combustion recirculation zone is increased by increasing the vane angle, so that the flame is stabilized at a position away from the fuel nozzle (2) by a certain distance; The first and second radial swirl vanes (13, 14) are flat vanes, the vane angle of the first radial swirl vane (13) is 30° to 40°, and the vane angle of the second radial swirl vane (14) is 35° to 45°, the swirl combustion recirculation zone is increased by increasing the vane angle, so that the flame is stabilized at a position away from the fuel nozzle (2) by a certain distance.

5. The hydrogen-facilitated liquid ammonia direct injection multistage swirl combustor of claim 1, wherein, The hydrogen injection port (22) is uniformly arranged outside the liquid ammonia injection port (21) in the circumferential direction, and the liquid ammonia provided by the liquid ammonia injection port (21) and the hydrogen provided by the hydrogen injection port (22) meet the hydrogen mixing ratio of 2%-5% by volume.

6. The hydrogen-facilitated liquid ammonia direct injection multistage swirl combustor of claim 1, wherein, The flame tube (3) is provided with a mixing hole (31), a secondary air hole (32) and a film cooling hole (33); along the fuel supply direction, the secondary air hole (32) is located upstream of the mixing hole (31), used to send air into the flame tube (3) to realize secondary combustion of ammonia; the mixing hole (31) is used to send air into the flame tube (3) to dilute the burned gas; the film cooling hole (33) is used to form a cooling gas film protective layer on the surface of the tube wall, along the fuel supply direction, the flame tube (3) is composed of a diverging section, a long cylindrical section and a converging section, and the mixing hole (31), the secondary air hole (32) and the film cooling hole (33) are arranged on the tube wall of the long cylindrical section.

7. The hydrogen-facilitated liquid ammonia direct injection multistage swirl combustion chamber of claim 1, wherein, The fuel nozzle (2) is configured to be movable along the axial direction of the combustor to adjust the moving distance according to different working conditions, and is moved away from the flame tube (3) when injecting large flow rate of liquid ammonia, to ensure sufficient mixing of fuel and air and promote stable combustion of liquid ammonia.

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