Integrated annular combustion chamber for combustion of cracked ammonia gas

Abstract

The invention relates to the technical field of ammonia gas combustion chambers, in particular to a cracking ammonia gas combustion integrated annular combustion chamber which comprises a flame tube body and an injection disc, an air inlet pipe used for introducing air is integrally formed at one end of the flame tube body, and a turbine is arranged on the inner side of the other end of the flame tube body; the gas inlet pipe is communicated with an annular cavity flow channel arranged in the flame tube body, one side of the annular cavity flow channel is communicated with a main combustion area, the end, away from the annular cavity flow channel, of the flame tube body is communicated with a gas flow channel communicated with the main combustion area, and the inner side of the flame tube body serves as a turbine exhaust emission channel. An ammonia gas cracking assembly used for introducing ammonia gas and partially cracking the ammonia gas is arranged, and a cooling assembly used for cooling the wall face of the main combustion area is further arranged in the flame barrel. The waste heat of turbine exhaust gas is used for heating an ammonia cracking catalyst, ammonia gas is partially cracked and then is fully mixed with air in a backflow area, so that efficient and stable combustion of the ammonia gas is ensured, the situation of difficult ignition is avoided, the combustion effect of the combustion chamber is improved, the NOx emission concentration is remarkably reduced through lean-burn combustion, and the combustion efficiency of the combustion chamber is improved. And through 3D printing integrated manufacturing, the sealing performance and heat efficiency of the combustion chamber are improved, and the production difficulty and cost of the combustion chamber are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of ammonia combustion chambers, and in particular to an integrated annular combustion chamber for cracking ammonia combustion. Background Art

[0002] Compared to traditional fossil fuels, ammonia currently suffers from drawbacks such as long ignition delay, low laminar flame speed, narrow flammability range, and high nitrogen oxide (NOx) emissions. This poses significant challenges to the structural design of gas turbine combustors and the organization of efficient, stable, and low-pollution combustion within them. Partially pre-cracking ammonia is an ideal method for improving its flammability, while burning it in a leaner manner can significantly reduce NOx emission concentrations. However, traditional combustors are not suitable for ammonia combustion, making efficient and stable combustion difficult to achieve, resulting in difficult ignition and high emissions. Furthermore, their complex structure, cumbersome manufacturing process, and difficult processing, welding, and assembly lead to long production cycles, increased manufacturing costs, and increased maintenance difficulties. Summary of the Invention

[0003] In order to overcome the shortcomings of the existing technology, the present invention provides an integrated annular combustion chamber for cracked ammonia combustion, which solves the problem that the existing technology is difficult to achieve efficient and stable combustion, resulting in difficult ignition and high pollution emissions.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions: an integrated annular combustion chamber for cracked ammonia combustion, comprising a flame cylinder and an injection disk, one end of the flame cylinder is integrally formed with an air intake pipe for introducing air, the other end of the flame cylinder is provided with a turbine inside, the air intake pipe is connected to an annular cavity flow channel provided in the flame cylinder, one side of the annular cavity flow channel is connected to the main combustion zone, the end of the flame cylinder away from the annular cavity flow channel is connected to a gas flow channel connected to the main combustion zone, the inner side of the flame cylinder serves as a turbine exhaust gas discharge channel and is provided with a An ammonia cracking assembly is provided for introducing ammonia and partially cracking it. A cooling assembly for cooling the wall of the main combustion zone is also provided in the flame tube body. A plurality of ammonia nozzles arranged equidistantly along the circumference are fixedly connected on the injection disk. The ammonia nozzles extend through the nozzle holes at one end of the flame tube body into the annular cavity flow channel. A swirler installed in the flame tube body is provided at one end of the ammonia nozzles. The swirler constrains the air flow entering through the air inlet pipe to generate axial velocity, forming a vortex airflow, which carries the ammonia into the main combustion zone and forms a recirculation zone near one end of the annular cavity flow channel in the main combustion zone.

[0005] As a further optimization scheme of the present invention, the ammonia cracking assembly includes an ammonia inlet flow channel arranged at the center of the flame cylinder, and a confluence cavity and an outlet flow channel arranged at one end of the inner side of the flame cylinder. The outlet flow channel is connected to one side of the confluence cavity, and a diversion channel is provided at one end of the ammonia inlet flow channel.

[0006] As a further optimization scheme of the present invention, the diversion channel is connected to a plurality of cracking channels distributed in a circular array, one end of the cracking channel is connected to the confluence chamber, an ammonia inlet connected to the outlet flow channel is provided on the injection disk, and an ammonia ring cavity connected to the ammonia inlet is provided on the inner side of the injection disk, and the ammonia ring cavity is connected to the ammonia nozzle.

[0007] As a further optimization scheme of the present invention, the cooling assembly includes an inner cooling channel arranged on the inner side of the main combustion zone and an outer cooling channel arranged on the outer side of the main combustion zone. The annular channel is connected to one end of the inner cooling channel through the inner cooling channel inlet, and the annular channel is connected to one end of the outer cooling channel through the outer cooling channel inlet.

[0008] As a further optimization scheme of the present invention, the other end of the inner cooling channel is connected to the main combustion zone through mixing hole 1, and the other end of the outer cooling channel is connected to the main combustion zone through mixing hole 2. A mixing hole is set at one end of the outer cooling channel inlet and the inner cooling channel inlet.

[0009] As a further optimization scheme of the present invention, a plurality of flange bolt holes 1 distributed in a circumferential array are opened at one end of the flame cylinder, a plurality of flange bolt holes 2 distributed in a circumferential array are opened on the injection disk, and the flame cylinder and the injection disk are connected by a flange.

[0010] As a further optimization solution of the present invention, one end of the flame tube body is further provided with a plurality of circumferentially distributed igniter holes 1, and one side of the igniter hole 1 is provided with an igniter hole 2 opened on the injection disk.

[0011] As a further optimization scheme of the present invention, an outer sealing gasket and an inner sealing gasket are fixed on one end of the flame cylinder body, an outer sealing gasket groove matching with the outer sealing gasket is provided on the injection disk, and an inner sealing gasket groove matching with the inner sealing gasket is also provided on the injection disk.

[0012] As a further optimization solution of the present invention, the outer wall surfaces of the main combustion zone are provided with reinforcing ribs for enhancing the structural strength of the combustion chamber.

[0013] By means of the above technical solution, the present invention provides an integrated annular combustion chamber for cracked ammonia combustion, which has at least the following beneficial effects compared to the prior art: 1. The present invention provides an ammonia cracking component and uses the waste heat of turbine exhaust gas to heat the ammonia cracking catalyst, thereby partially cracking the ammonia into nitrogen and hydrogen. The hydrogen will greatly increase the combustibility of the fuel. While ensuring the complete reaction of ammonia, the lean burn combustion significantly reduces the NOx emission concentration, making it more environmentally friendly.

[0014] 2. The combustion chamber of the present invention is composed of a flame cylinder body and an injection disk with an annular structure. The swirler and the ammonia nozzle are arranged coaxially. When ammonia is injected into the flame cylinder body through the injection disk, the rotation of the swirler generates a vortex airflow, so that the ammonia and air are fully mixed in the recirculation zone, thereby ensuring that the ammonia can burn efficiently and stably, avoiding the occurrence of ignition difficulties and high pollution emissions, and improving the combustion effect of the combustion chamber.

[0015] 3. The flame tube body of the present invention is manufactured by integrated 3D printing, which simplifies the combustion chamber structure, reduces the connection gaps between components, improves the sealing and thermal efficiency of the combustion chamber, reduces the production difficulty and cost of the combustion chamber, and is more convenient for later inspection and maintenance.

[0016] 4. The present invention integrates the ammonia cracking component with the combustion chamber, which has a simple and compact structure. It uses the waste heat of the gas after the turbine works to heat the ammonia cracking catalyst, thereby increasing the thermal efficiency of the system and reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a front cross-sectional view of the present invention; Figure 3 is a side sectional view of the present invention; Figure 4 It is a structural schematic diagram of the injection disk of the present invention; Figure 5 Schematic diagram of the back side of the injection disk of the present invention; Figure 6 It is a cross-sectional view of the injection disk of the present invention.

[0018] In the figure: 1. Inlet pipe; 2. Flange bolt hole 1; 3. Nozzle hole; 4. Ignitor hole 1; 5. Outer sealing gasket; 6. Inner sealing gasket; 7. Flame tube; 8. Ammonia inlet flow channel; 9. Converging cavity; 10. Outlet flow channel; 11. Annular cavity flow channel; 12. Swirl; 13. Main combustion zone; 14. Outer cooling flow channel inlet; 15. Inner cooling flow channel inlet; 16. Outer cooling flow channel; 17. Inner cooling flow channel; 18. Reinforcement rib; 19. Primary mixing hole; 20. Mixing hole 1; 21. Mixing hole 2; 22. Gas flow channel; 23. Turbine; 24. Diverter channel; 25. Cracking channel; 26. Cracking catalyst; 27. Ammonia nozzle; 28. Flange bolt hole 2; 29. ​​Ignitor hole 2; 30. Inner sealing gasket groove; 31. Outer sealing gasket groove; 32. Ammonia inlet; 33. Ammonia annular cavity. DETAILED DESCRIPTION

[0019] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] First embodiment Due to the poor flammability of ammonia, it is difficult for traditional combustion chambers to achieve efficient and stable combustion, making ignition difficult and causing high pollution emissions. In order to ensure that ammonia can burn efficiently and stably and improve the combustion effect of the combustion chamber, refer to Figure 1 - Figure 6 This embodiment provides an integrated annular combustion chamber for cracked ammonia combustion, which is composed of a flame cylinder 7 and an injection disk, and is made of GH3625 material. One end of the flame cylinder 7 is provided with a plurality of flange bolt holes 2 distributed in a circumferential array, and the injection disk is provided with a plurality of flange bolt holes 28 distributed in a circumferential array. The flame cylinder 7 and the injection disk are fixedly connected by a flange.

[0021] An outer sealing gasket 5 and an inner sealing gasket 6 are also fixed to one end of the flame cylinder body 7. The injection disk is provided with an outer sealing gasket groove 31 that matches the outer sealing gasket 5, and the injection disk is also provided with an inner sealing gasket groove 30 that matches the inner sealing gasket 6. When the injection disk is installed on the flame cylinder body 7, the outer sealing gasket 5 is inserted into the outer sealing gasket groove 31, and the inner sealing gasket 6 is inserted into the inner sealing gasket groove 30, so that the sealing between the injection disk and the flame cylinder body 7 is greatly enhanced.

[0022] An air intake pipe 1 for introducing air is integrally formed at one end of the flame cylinder 7, and a turbine 23 is provided on the inner side of the other end of the flame cylinder 7. The material of the turbine 23 in this embodiment, such as ceramic, can withstand the high temperature of the fuel gas. The high-temperature fuel gas of the flame cylinder 7 then works on the turbine 23 to start the turbine 23. The air intake pipe 1 is connected to an annular flow channel 11 provided in the flame cylinder 7, and one side of the annular flow channel 11 is connected to the main combustion zone 13. Air enters the annular flow channel 11 tangentially through the air intake pipe 1, and the end of the flame cylinder 7 away from the annular flow channel 11 is connected to a fuel gas flow channel 22 connected to the main combustion zone 13.

[0023] Nine ammonia nozzles 27 are fixedly connected to the injection disk and are arranged equidistantly along the circumference. The ammonia nozzles 27 adopt a straight nozzle configuration, which can make the flame distribution in the flame cylinder 7 more uniform. The ammonia nozzles 27 pass through the nozzle hole 3 at one end of the flame cylinder 7 and extend into the annular cavity flow channel 11. A swirler 12 is provided at one end of the ammonia nozzle 27 and is installed in the flame cylinder 7. The swirler 12 consists of 6 swirl blades. The ammonia nozzles 27 correspond to the swirler 12 in one-to-one position and are in the same position. The axis is set, the ammonia nozzle 27 can be inserted into the swirler 12, the outlet of the ammonia nozzle 27 is retracted 1mm, ammonia is ejected directly from the inner ring of the ammonia nozzle 27, and air is ejected from the outer ring with a swirl. The air can carry the ammonia into the main combustion zone 13, and the swirler 12 constrains the air flow entering through the inlet pipe 1 to generate axial velocity, forming a vortex airflow, carrying the ammonia into the main combustion zone 13, and forming a recirculation zone in the main combustion zone 13 near one end of the annular cavity flow channel 11.

[0024] Since the flame speed of ammonia is low, in order to ensure stable combustion of ammonia, its injection speed should not be too high. In this embodiment, the ammonia flow rate is 6.85g / s, the diameter of the ammonia nozzle 27 is set to 4mm, and the injection speed of ammonia is 17m / s; one end of the flame cylinder 7 is also provided with three circumferentially distributed igniter holes 4, and one side of the igniter hole 4 is provided with an igniter hole 29 opened on the injection disk. The three igniter holes 29 are evenly arranged between the nine ammonia nozzles 27, which can ignite the mixture of ammonia and air to ensure the smooth start of the combustion process.

[0025] In order to enhance its combustibility and ensure complete reaction of ammonia while adopting lean-burn combustion to significantly reduce NOx emission concentration, an ammonia cracking assembly for introducing ammonia and partially cracking it is provided on the inner side of the flame cylinder 7. The ammonia cracking assembly includes an ammonia inlet flow channel 8 provided at the center of the flame cylinder 7, a confluence chamber 9 provided at one end of the inner side of the flame cylinder 7, and an outlet flow channel 10. The outlet flow channel 10 is connected to one side of the confluence chamber 9. A diversion channel 24 is provided at one end of the ammonia inlet flow channel 8. The diversion channel 24 is connected to twelve cracking channels 25 distributed in a circumferential array. One end of the cracking channel 25 is connected to the confluence chamber 9. A cracking catalyst 26 is installed in the cracking channel 25. After the high-temperature combustion gas has done work on the turbine 23, the combustion gas is discharged from the central channel of the flame cylinder 7 and exchanges heat with the cracking channel 25 to heat the ammonia cracking catalyst. When the ammonia flows through the cracking channel 25, it is catalyzed by the high temperature and partially cracked into nitrogen and hydrogen. The hydrogen will greatly increase the combustibility of the fuel.

[0026] An ammonia inlet 32 ​​connected to the outlet flow channel 10 is provided on the injection disk, and an ammonia ring cavity 33 connected to the ammonia inlet 32 ​​is provided on the inner side of the injection disk. The cross-section of the ammonia ring cavity 33 is set to be pagoda-shaped, which is conducive to one-piece molding and manufacturing, and the ammonia ring cavity 33 is connected to the ammonia nozzle 27. Part of the cracked ammonia enters the confluence cavity 9, is then discharged from the outlet flow channel 10, and then enters the ammonia ring cavity 33 of the injection disk through the ammonia inlet 32.

[0027] The flame tube body 7 is also provided with a cooling assembly for cooling the wall of the main combustion zone 13. The cooling assembly includes an inner cooling channel 17 provided inside the main combustion zone 13 and an outer cooling channel 16 provided outside the main combustion zone 13. The annular channel 11 is connected to one end of the inner cooling channel 17 through the inner cooling channel inlet 15. The annular channel 11 is connected to one end of the outer cooling channel 16 through the outer cooling channel inlet 14. The air entering the annular channel 11 is divided into three streams. One stream passes through the swirler 12. Enter the main combustion zone 13, and at the same time, the other two gases enter the outer cooling channel 16 and the inner cooling channel 17 through the outer cooling channel inlet 14 and the inner cooling channel inlet 15 respectively. The airflow forms a layer of air film protection layer on the outer wall of the main combustion zone 13, which is used to cool the wall of the main combustion zone 13 and prevent the high-temperature gas from burning the wall of the main combustion zone 13. A primary mixing hole 19 is provided at one end of the outer cooling channel inlet 14 and the inner cooling channel inlet 15, where a small amount of air enters the main combustion zone 13 tangentially.

[0028] The outer wall surface of the main combustion zone 13 is provided with reinforcing ribs 18, which are used to enhance the structural strength of the combustion chamber, improve the safety of the entire combustion chamber, and extend the service life of the combustion chamber.

[0029] The annular combustion chamber structure can achieve efficient, stable and low-pollution combustion of 30wt% cracked ammonia in the main combustion zone 13 at an equivalence ratio of 0.54 and an overall equivalence ratio of 0.19, with a combustion efficiency of 96% and a NOx emission concentration of 376ppm.

[0030] Second embodiment In order to expand the application range of the combustion chamber, match the turbine 23 with different materials, and extend the service life of the turbine 23, refer to Figure 2The difference between this embodiment and the second embodiment is that when the material of the turbine 23, such as a high-temperature alloy, cannot withstand the high temperature of the combustion gas, a mixing hole 20 connected to the main combustion zone 13 is provided at the other end of the inner cooling channel 17, and a mixing hole 21 connected to the main combustion zone 13 is provided at the other end of the outer cooling channel 16. The cooled air enters the main combustion zone 13 from the outer cooling channel 16 through the mixing hole 21, and the cooled air enters the main combustion zone 13 from the inner cooling channel 17 through the mixing hole 20, mixes and cools the combustion gas, and then works on the turbine 23, thereby providing a certain degree of protection for the turbine 23 and extending the service life of the turbine 23.

[0031] The present invention comprises an annular combustion chamber formed by the flame cylinder 7 and the injection disk, and a coaxially arranged ammonia nozzle 27 and swirler 12. At the same time, the ammonia cracking assembly utilizes the high-temperature catalytic effect in the cracking channel 25 to crack part of the ammonia into nitrogen and hydrogen. The hydrogen will greatly increase the combustibility of the fuel, enhance its flammability, ensure that the ammonia can burn efficiently and stably, and improve the combustion effect of the entire combustion chamber.

[0032] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0033] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications and variations may be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An integrated annular combustion chamber for cracked ammonia combustion, characterized by: It comprises a flame cylinder (7) and an injection disk, wherein an air inlet pipe (1) for introducing air is integrally formed at one end of the flame cylinder (7), and a turbine (23) is provided inside the other end of the flame cylinder (7); The air inlet pipe (1) is connected to an annular cavity flow channel (11) provided in the flame cylinder (7), one side of the annular cavity flow channel (11) is connected to the main combustion zone (13), and the end of the flame cylinder (7) away from the annular cavity flow channel (11) is connected to a fuel gas flow channel (22) connected to the main combustion zone (13). An ammonia cracking component for introducing ammonia and partially cracking it is provided on the inner side of the flame cylinder (7), and a cooling component for cooling the wall of the main combustion zone (13) is also provided in the flame cylinder (7); A plurality of ammonia nozzles (27) are fixedly connected to the injection disk and are arranged at equal intervals along the circumference. The ammonia nozzles (27) extend through the nozzle holes (3) at one end of the flame tube body (7) into the annular cavity flow channel (11). A swirler (12) installed in the flame tube body (7) is provided at one end of the ammonia nozzle (27). The swirler constrains the air flow entering through the air inlet pipe (1) to generate axial velocity, forming a vortex airflow, which carries the ammonia into the main combustion zone (13) and forms a recirculation zone near one end of the annular cavity flow channel (11) in the main combustion zone (13).

2. The integrated annular combustion chamber for cracked ammonia combustion according to claim 1, characterized in that: The ammonia cracking assembly comprises an ammonia inlet flow channel (8) arranged at the center of the flame cylinder (7), a confluence cavity (9) and an outlet flow channel (10) arranged at one end of the inner side of the flame cylinder (7), the outlet flow channel (10) being connected to one side of the confluence cavity (9), and a diversion channel (24) being provided at one end of the ammonia inlet flow channel (8).

3. The integrated annular combustion chamber for cracked ammonia combustion according to claim 2, characterized in that: The diversion channel (24) is connected to a plurality of cracking channels (25) distributed in a circumferential array. One end of the cracking channel (25) is connected to the confluence chamber (9). An ammonia inlet (32) connected to the outlet flow channel (10) is provided on the injection disk. An ammonia annular cavity (33) connected to the ammonia inlet (32) is provided on the inner side of the injection disk, and the ammonia annular cavity (33) is connected to the ammonia nozzle (27).

4. The integrated annular combustion chamber for cracked ammonia combustion according to claim 1, characterized in that: The cooling assembly includes an inner cooling channel (17) arranged inside the main combustion zone (13) and an outer cooling channel (16) arranged outside the main combustion zone (13), the annular channel (11) is connected to one end of the inner cooling channel (17) through the inner cooling channel inlet (15), and the annular channel (11) is connected to one end of the outer cooling channel (16) through the outer cooling channel inlet (14).

5. The integrated annular combustion chamber for cracked ammonia combustion according to claim 4, characterized in that: The other end of the inner cooling channel (17) is connected to the main combustion zone (13) through the mixing hole 1 (20), and the other end of the outer cooling channel (16) is connected to the main combustion zone (13) through the mixing hole 2 (21). A primary mixing hole (19) is provided at one end of the outer cooling channel inlet (14) and the inner cooling channel inlet (15).

6. The integrated annular combustion chamber for cracked ammonia combustion according to claim 1, characterized in that: One end of the flame cylinder (7) is provided with a plurality of flange bolt holes (2) distributed in a circumferential array, and the injection disk is provided with a plurality of flange bolt holes (28) distributed in a circumferential array, and the flame cylinder (7) and the injection disk are connected via a flange.

7. The integrated annular combustion chamber for cracked ammonia combustion according to claim 1, characterized in that: One end of the flame tube body (7) is further provided with a plurality of circumferentially distributed igniter holes (4), and one side of the igniter hole (4) is provided with an igniter hole (29) opened on the injection disk.

8. The integrated annular combustion chamber for cracked ammonia combustion according to claim 1, characterized in that: An outer sealing gasket (5) and an inner sealing gasket (6) are fixed to one end of the flame cylinder body (7), an outer sealing gasket groove (31) matching with the outer sealing gasket (5) is provided on the injection disk, and an inner sealing gasket groove (30) matching with the inner sealing gasket (6) is also provided on the injection disk.

9. The integrated annular combustion chamber for cracked ammonia combustion according to claim 1, characterized in that: The outer wall surfaces of the main combustion zone (13) are provided with reinforcing ribs (18) for enhancing the structural strength of the combustion chamber.

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