Carbon emission reduction swirled staged combustion device for ammonia gas turbine

Abstract

The application discloses an ammonia gas turbine carbon emission reduction cyclone staged combustion device, which comprises a primary combustion chamber, a rapid mixing device and a secondary combustion chamber, the primary combustion chamber is connected with a head assembly at the front side, the rapid mixing device is connected with the primary combustion chamber and the secondary combustion chamber respectively, and a cyclone assembly is arranged in the rapid mixing device; the head assembly comprises a primary fuel injection gun, a primary air injection gun and an air cyclone, the primary combustion chamber comprises a primary combustion chamber hearth, the primary fuel injection gun and the primary air injection gun are connected with the primary combustion chamber hearth, and the air cyclone is connected with the primary combustion chamber hearth through a pipeline; the secondary combustion chamber comprises a secondary combustion chamber hearth, and the secondary combustion chamber hearth is connected with a smoke outlet. The application improves the ammonia combustion stability, component oxidation residence time, oxidation rate, carbon monoxide emission and nitrogen oxide emission reduction, improves the ammonia premixing cyclone combustion flame stability and combustion limit, and improves the adaptability of the ammonia combustion device to different working conditions and different equivalence ratios.

Description

Technical Field

[0001] This invention relates to the field of green and low-carbon combustion technology for ammonia gas turbines, and in particular to a staged combustion device for ammonia gas turbines. Background Technology

[0002] Ammonia is an important fuel for the combustion chambers of future new gas turbines. Gas turbine combustion technology is developing towards higher combustion efficiency, lower pollutant emissions, and wider flammability limits. Lean premixing, swirl diffusion, dilution diffusion, and dry low-NOx combustion are traditional combustion technologies for conventional fuels. In lean premixed combustion technology, reactants burn at a low stoichiometric ratio, achieving low flame temperature and low NOx emissions. To further reduce NOx emissions, the lean combustion limit needs to be lowered. Adding H2 to CH4 can broaden the combustible range and improve combustion stability at low stoichiometric ratios, but may induce backfire. In swirling diffusion combustion, the swirling promotes the mixing of backflow flue gas and fresh unburned gas, increasing the residence time of reactants in the burner and reducing CO emissions. However, reactants on the flame front burn at near-stoichiometric ratios, resulting in high flame temperatures, which is not conducive to NOx reduction. Dilution diffusion combustion uses water or steam to dilute reactants, absorb the exothermic reaction, and lower the flame temperature, reducing NOx emissions. However, its emission reduction potential is limited and may increase CO emissions. DLN is a combustion chamber technology widely used by gas turbine manufacturers based on the widespread application of natural gas fuels. GE's MS9001H natural gas gas turbine uses this technology. With increasing attention to environmental issues and the continuous consumption of traditional fossil fuels, it is necessary to develop combustion technologies that can simultaneously reduce NOx and CO emissions.

[0003] The widespread use of fossil fuels has led to severe greenhouse gas emissions, making the development of green combustion devices a new trend. Ammonia combustion produces no carbon emissions and is currently the most promising new energy fuel. Promoting the application of ammonia fuel in industrial heating is an important means of carbon reduction. Compared to hydrogen fuel, ammonia has the advantages of easy storage and long-distance, high-flow transportation. Ammonia's reactivity is much lower than hydrogen's, therefore its storage and transportation costs are significantly lower, facilitating large-scale commercial application. Industries such as power, steel, and chemicals extensively use combustion devices. These devices are currently designed and developed based on traditional natural gas, coal gas, and process waste gas, and cannot be directly used for the combustion of low-reactivity ammonia. Therefore, new combustion devices specifically designed and developed for ammonia combustion characteristics are needed.

[0004] Ammonia has characteristics such as low calorific value, difficulty in ignition, and slow combustion speed. There is no effective solution for ammonia combustion. Using traditional jet nozzles for ammonia combustion leads to problems such as difficulty in ignition, incomplete combustion, and ammonia leakage. Therefore, developing a nozzle layout that conforms to the combustion characteristics of ammonia aligns with the current trend of green and low-carbon combustion. Summary of the Invention

[0005] This invention aims to overcome the shortcomings of existing technologies by providing a staged combustion device for ammonia gas turbines. The swirling staged combustion device of this invention improves ammonia combustion stability, component oxidation residence time, and oxidation rate, reducing carbon monoxide emissions while simultaneously reducing nitrogen oxide emissions. Compared to existing integral combustion devices, the staged combustion device enhances the adaptability of the combustion device to different industrial scenarios, making it suitable for gas turbines with varying loads, operating conditions, and fuel characteristics. It is also suitable for a wide range of ammonia mixing ratios, improving adaptability to different processes in industrial settings. Furthermore, by employing a swirling burner, it improves the stability and combustion limits of the ammonia premixed swirling combustion flame, enhancing the adaptability of the ammonia combustion device to different operating conditions and equivalence ratios.

[0006] The technical solution adopted by this invention to solve its technical problem is:

[0007] A carbon emission reduction swirl staged combustion device for an ammonia gas turbine includes a primary combustion chamber connected to a front head assembly, a rapid mixing device, and a secondary combustion chamber. The rapid mixing device is connected to both the primary and secondary combustion chambers, and a swirler assembly is provided within the rapid mixing device.

[0008] The head assembly at the front of the primary combustion chamber includes a primary fuel injector, a primary air injector, and an air cyclone separator. The primary combustion chamber includes a primary combustion chamber furnace. The primary fuel injector and the primary air injector are connected to the primary combustion chamber furnace through pipes. The primary fuel injector and the primary air injector respectively introduce primary air and primary fuel into the primary combustion chamber furnace.

[0009] The air cyclone separator is connected to the primary combustion chamber furnace via a pipe;

[0010] The secondary combustion chamber includes a secondary combustion chamber furnace, which is connected to the flue gas outlet.

[0011] The primary fuel injector is located at the center of the head assembly, and the cross-sections of the primary fuel injector, the primary air injector, and the bottom surface of the primary combustion chamber are flush.

[0012] The bottom surface of the primary combustion chamber is connected to multiple primary air spray guns, which are located near the bottom of the furnace and evenly distributed along the circumference.

[0013] One type of fuel spray gun is arranged in the inner ring, and the other type of air spray gun is arranged in the outer ring.

[0014] The diameter of the primary fuel injection gun is not less than 1.8 mm;

[0015] The diameter of the primary air spray gun shall not be less than 3mm;

[0016] The diameter of the primary combustion chamber furnace or hydraulic diameter is 10 to 30 times the diameter of the primary air spray gun;

[0017] The height of the primary combustion chamber furnace is 1 to 5.5 times the diameter of the primary combustion chamber furnace or the hydraulic diameter;

[0018] The injection speed of the primary fuel injector is ≤120m / s.

[0019] The rapid mixing device includes a secondary fuel spray gun for introducing secondary fuel, a secondary air spray gun for introducing secondary air, and a mixing chamber. The secondary fuel spray gun and the secondary air spray gun are respectively connected to the mixing chamber through pipes.

[0020] The secondary fuel spray gun adopts a hollow straight cylindrical structure made of high-temperature resistant metal material. The secondary fuel spray gun tangentially penetrates the outer wall of the mixing chamber and is welded to ensure that after the secondary fuel enters the mixing chamber, the airflow impacts the inner wall of the mixing chamber, forming a stagnant backflow vortex, which allows the secondary fuel to rotate. The secondary air spray gun adopts a hollow straight cylindrical structure made of high-temperature resistant metal material. The secondary air spray gun tangentially penetrates the outer wall of the mixing chamber 17 and is welded to ensure that after the secondary air enters the mixing chamber, the airflow impacts the inner wall of the mixing chamber, forming a stagnant backflow vortex, which allows the secondary air to rotate.

[0021] The secondary fuel spray gun and the secondary air spray gun enter in the same tangential direction.

[0022] The lower section of the mixing chamber is flush with the top surface of the primary combustion chamber furnace, which serves to seal the primary combustion chamber furnace. The upper section of the mixing chamber is flush with the bottom surface of the secondary combustion chamber furnace, which serves to seal the secondary combustion chamber furnace.

[0023] The secondary fuel spray gun is arranged on the outer wall of the mixing chamber, and the secondary air spray gun is arranged on the outer wall of the mixing chamber. The secondary fuel spray gun and the secondary air spray gun are evenly spaced in a circular arrangement.

[0024] The circumferential cross-section of the secondary fuel spray gun and the circumferential cross-section of the secondary air spray gun are at the same height, and the fuel spray gun and the air spray gun are arranged alternately, or the circumferential cross-section of the secondary fuel spray gun and the circumferential cross-section of the secondary air spray gun do not coincide, and the fuel spray gun and the air spray gun are arranged in a staggered manner, so that the secondary fuel and the secondary air are jetted and flowed independently and enter the mixing chamber for mixing.

[0025] The secondary fuel spray guns are arranged on the same circumferential cross section. The secondary fuel spray guns enter the mixing chamber tangentially with a tangential angle of not less than 15° and a secondary fuel swirl number of not less than 0.3.

[0026] The secondary air spray guns are arranged on the same circumferential cross section. The secondary air spray guns enter the mixing chamber tangentially with a tangential angle of not less than 30° and a secondary air swirl number of not less than 0.4.

[0027] The diameter of the secondary fuel spray gun is not less than 1.8 mm;

[0028] The diameter of the secondary air spray gun is not less than 3mm;

[0029] The diameter of the mixing chamber or the hydraulic diameter is 10 to 30 times the diameter of the secondary air spray gun;

[0030] The height of the mixing chamber is 0.1 to 3 times the diameter of the mixing chamber or the hydraulic diameter;

[0031] The outer diameter of the mixing chamber is the same as the inner diameter of the secondary combustion chamber furnace.

[0032] The secondary fuel spray gun injection speed is ≤120m / s;

[0033] The secondary air spray gun has a spray speed of ≤110m / s.

[0034] The beneficial effects of this invention are:

[0035] 1. The swirl-stage combustion device of the present invention can improve the combustion stability of ammonia, the oxidation residence time of components, increase the oxidation rate, and reduce carbon monoxide emissions while simultaneously reducing nitrogen oxide emissions. Compared with the existing integral combustion device, the staged combustion device can improve the adaptability of the combustion device to different industrial scenarios, and is suitable for gas turbines with varying loads, operating conditions, and fuel characteristics. It is also suitable for a wide range of ammonia mixing ratios, improving the adaptability to different processes in industrial scenarios. At the same time, by adopting a swirl burner, the stability and combustion limit of the ammonia premixed swirl combustion flame are improved, enhancing the adaptability of the ammonia combustion device to different operating conditions and different equivalence ratios.

[0036] 2. The inner ring arrangement of the fuel injector in the primary combustion chamber 1 is conducive to increasing the local concentration of primary fuel 12 and improving combustion stability. The outer ring arrangement of the air injector in the primary combustion chamber can promote the rapid mixing of air and fuel and improve the combustion efficiency of the primary combustion chamber 1.

[0037] 3. Overall, the staged injection of fuel and air allows for convenient adjustment of the equivalence ratio and injection speed of the primary and secondary combustion chambers, as well as the fuel and air distribution ratios of the primary and secondary combustion chambers, enabling real-time adjustment of combustion performance.

[0038] 4. By providing secondary fuel and secondary air through a rapid mixing device, the fuel and air are injected in a dispersed manner, which can expand the volume of the reaction zone, reduce the maximum flame temperature in the secondary combustion chamber, make the temperature distribution more uniform, and reduce the formation of thermal NOx.

[0039] 5. The secondary fuel spray gun and secondary air spray gun of the rapid mixing device are arranged tangentially, allowing the secondary fuel and secondary air to swirl into the mixing chamber. The swirl can improve the stability of ammonia combustion and increase ammonia combustion efficiency.

[0040] 6. The primary and secondary combustion chambers are arranged in an axial stage. The NOx emissions generated in the primary combustion chamber enter the secondary combustion chamber and mix with the secondary fuel, which can reduce the NOx emissions from the primary combustion chamber and further reduce NOx emissions.

[0041] 7. The swirl staged combustion device has a simple structure and is easy to implement. When used in ammonia gas turbines, it can reduce carbon emissions and nitrogen oxide emissions, achieving nitrogen oxide emissions of less than 50mg without affecting the efficiency of the gas turbine. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the carbon emission reduction swirl staged combustion device for ammonia gas turbine according to the present invention;

[0043] Figure 2 This is a schematic diagram of the swirl combustion device and the detection device.

[0044] Figure 3 The diagram shows the distribution of the mixed planar flow traces under tangential swirling flow with a flue gas recirculation ratio of 0.4.

[0045] Figure 4 The diagram shows the distribution of the mixed planar flow traces under tangential swirling flow with a flue gas recirculation ratio of 0.7.

[0046] Figure 5 Image of the flame in the secondary combustion zone of staged combustion under tangential swirl with a flue gas recirculation ratio of 0.67;

[0047] Figure 6 Image of the flame in the secondary combustion zone of staged combustion under tangential swirl with a flue gas recirculation ratio of 1.0;

[0048] Figure 7 Image of the flame in the secondary combustion zone of staged combustion under a tangential swirl with a flue gas recirculation ratio of 1.5;

[0049] Figure 8 This is a flame image of the secondary combustion zone under staged combustion with a flue gas recirculation ratio of 2.3 and tangential swirl.

[0050] In the diagram, 11-Primary air; 12-Primary fuel; 13-Air cyclone separator; 14-Primary combustion chamber; 15-Secondary air; 16-Secondary fuel; 17-Mixing chamber; 18-Secondary combustion chamber; 19-Exhaust port; 21-Flue gas sampling pipe; 22-Cooling water jacket; 23-Flue gas analyzer; 24-Digital camera; 25-Water inlet; 26-Mixing device structure; 27-Quartz glass tube; 28-Enhanced ICCD camera; 29-Secondary air spray gun one; 210-Secondary fuel spray gun one; 211-Secondary air spray gun two; 212-Secondary fuel spray gun two; 213-Water outlet. Detailed Implementation

[0051] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments.

[0052] like Figure 1-8 As shown, the present invention provides a staged combustion device for an ammonia gas turbine, including a primary combustion chamber 14 connected to a front head assembly, a mixing chamber 17 and a secondary combustion chamber 18, a rapid mixing device connected to the primary combustion chamber 14 and the secondary combustion chamber 18 respectively, the secondary combustion chamber 18 being connected to a flue gas outlet 19, and a cyclone assembly provided in the rapid mixing device.

[0053] The head assembly at the front of the primary combustion chamber includes a primary fuel injector and a primary air injector. The primary combustion chamber includes a primary combustion chamber furnace, which has a cylindrical or square structure. The primary fuel injector and the primary air injector are connected to the primary combustion chamber furnace through pipes, and the primary fuel injector and the primary air injector respectively introduce primary air 11 and primary fuel 12 into the primary combustion chamber furnace.

[0054] The head assembly also includes an air cyclone separator 13, which is connected to the primary combustion chamber furnace via a pipe. Its function is to promote the mixing of primary air and primary fuel through the swirling flow of primary air, thereby improving combustion efficiency and stable combustion of the primary fuel, thus enhancing combustion safety. The air cyclone separator of this invention can adjust its swirling intensity according to the proportion of ammonia mixed with other combustion gases, ensuring carbon emission reduction performance under different ammonia mixing ratios. With a low ammonia mixing ratio, the swirling intensity of the separator weakens, shortening the residence time of reactants in the high-temperature zone while ensuring combustion stability, thus reducing the generation of thermal and fuel-type nitrogen oxides. With a high ammonia mixing ratio, the swirling intensity of the separator strengthens, forming a high-intensity eddy stagnation zone. Through the residence and combustion of reactants in the stagnation zone, combustion stability and operational safety of the device are improved.

[0055] The primary fuel injector is positioned at the center of the head assembly, surrounded by primary air to promote full contact between the primary fuel and primary air. Furthermore, the primary air's heat insulation protects the primary combustion chamber, reducing the direct impact of the primary fuel and its flame on the combustion chamber walls, thus protecting the combustion chamber walls, reducing the risk of coking, and extending the service life of the combustion chamber. The cross-sections of the primary fuel injector and primary air injector are flush with the bottom surface of the primary combustion chamber furnace, sealing the furnace while simultaneously injecting fuel and air into the primary combustion chamber.

[0056] The bottom surface of the primary combustion chamber is connected to multiple air spray guns, which are located near the bottom of the furnace and evenly distributed along the circumference.

[0057] The primary fuel injector is arranged in the inner ring, and the primary air injector is arranged in the outer ring. The primary fuel and primary air are jetted and flowed independently, and then enter the primary combustion chamber to mix.

[0058] The diameter of the primary fuel injection gun is not less than 1.8 mm. This parameter is limited because the present invention develops an ammonia burner based on the carbon emission reduction requirements of gas turbine operating conditions. Ammonia has low chemical reactivity, and using a 1.8 mm injection gun diameter promotes fuel injection speed and flue gas recirculation, which is beneficial to flue gas recirculation and inhibits the chemical formation of fuel-type nitrogen oxides.

[0059] The diameter of the primary air injection gun is not less than 3 mm. A primary air injection gun diameter of not less than 3 mm can balance the need to reduce CO2 emissions and suppress nitrogen oxide generation when developing ammonia burners under gas turbine operating conditions. By matching the injection velocities of primary air and primary fuel, the generation of a shear flow layer between the primary fuel and primary air is promoted.

[0060] The diameter of the primary combustion chamber furnace or hydraulic diameter is 10 to 30 times the diameter of the primary air nozzle. To develop a carbon-reducing ammonia burner for gas turbine operation, sufficient lateral space must be provided for the primary fuel and primary air to form a shear flow layer and a flue gas recirculation vortex. Sufficient shear flow ensures adequate contact and mixing of fuel and air, while the flue gas recirculation vortex ensures sufficient recirculation of high-temperature, low-oxygen flue gas back to the head space of the primary combustion chamber, increasing the inlet reactant temperature, improving combustion stability, and ensuring combustion efficiency.

[0061] The height of the primary combustion chamber is 1 to 5.5 times the diameter of the primary combustion chamber or the hydraulic diameter. This design addresses the need to ensure combustion intensity and improve the compactness of the primary combustion chamber when developing a carbon-reducing ammonia burner for gas turbine operation. Based on experimental verification, a combustion intensity suitable for high-pressure gas turbine operation is proposed, while simultaneously ensuring high-efficiency, low-carbon, and low-pollution combustion performance.

[0062] Furthermore, the injection velocity of the primary fuel injector is ≤120m / s. To ensure carbon reduction in ammonia burners operating under gas turbine conditions, the primary fuel injection velocity must not be too high. A velocity exceeding 120m / s can cause deflaking or extinguishing of the chemically inactive ammonia fuel, which is detrimental to the safe and stable combustion of the ammonia burner.

[0063] The secondary combustion chamber 18 includes a secondary combustion chamber furnace, which is connected to the flue gas outlet. The secondary combustion chamber furnace adopts a cylindrical or square structure.

[0064] The rapid mixing device includes a secondary fuel spray gun, a secondary air spray gun, and a mixing chamber 17. The secondary fuel spray gun and the secondary air spray gun are connected to the mixing chamber 17 through pipes to introduce secondary air 15 and secondary fuel 16.

[0065] The secondary fuel spray gun is made of high-temperature resistant metal material and has a hollow straight cylindrical structure. The secondary fuel spray gun tangentially penetrates the outer wall of the mixing chamber 17 and is welded thereon. This tangential welding structure ensures that after the secondary fuel enters the mixing chamber, the airflow impacts the inner wall of the mixing chamber, forming a stagnant backflow vortex, which allows the secondary fuel to rotate. The secondary air spray gun is also made of high-temperature resistant metal material and has a hollow straight cylindrical structure. The secondary air spray gun tangentially penetrates the outer wall of the mixing chamber 17 and is welded thereon. This tangential welding structure ensures that after the secondary air enters the mixing chamber, the airflow impacts the inner wall of the mixing chamber, forming a stagnant backflow vortex, which allows the secondary air to rotate.

[0066] The secondary fuel injector and the secondary air injector enter in the same tangential direction. This consistency facilitates the co-rotation and mixing of fuel and air, promotes the formation of a parallel shear flow layer between fuel and air, promotes full contact between fuel and air molecules, ensures oxidation time, and improves combustion efficiency.

[0067] The lower cross-section of the mixing chamber 17 is flush with the top surface of the primary combustion chamber 14, thus sealing the primary combustion chamber 14. The upper cross-section of the mixing chamber 17 is flush with the bottom surface of the secondary combustion chamber 18, thus sealing the secondary combustion chamber 18. The mixing chamber adopts a cylindrical or square structure.

[0068] The secondary fuel spray gun and the secondary air spray gun are arranged on the outer wall of the mixing chamber 17, and are evenly spaced in a circular arrangement. The circumferential cross-sections of the secondary fuel spray gun and the secondary air spray gun are at the same height, with the fuel and air spray guns spaced apart; or the circumferential cross-sections of the secondary fuel spray gun and the secondary air spray gun are not coincident, and are staggered. The height of the circumference of the secondary fuel and secondary air spray guns is determined according to the combustion conditions. The secondary fuel 16 and secondary air 15 are jetted and flow independently, entering the mixing chamber 17 to mix.

[0069] The secondary fuel spray guns are arranged on the same circumferential cross section, and enter the mixing chamber 17 tangentially with an angle of not less than 15° and a secondary fuel swirl number of not less than 0.3. The secondary air spray guns are arranged on the same circumferential cross section, and enter the mixing chamber 17 tangentially with an angle of not less than 30° and a secondary air swirl number of not less than 0.4.

[0070] The diameter of the secondary fuel spray gun is not less than 1.8 mm.

[0071] The diameter of the secondary air spray gun is not less than 3mm.

[0072] The diameter of the mixing chamber 17 or the hydraulic diameter is 10 to 30 times the diameter of the secondary air spray gun.

[0073] The height of the mixing chamber 17 is 0.1 to 3 times the diameter of the mixing chamber 17 or the hydraulic diameter.

[0074] The outer diameter of the mixing chamber 17 is the same as the inner diameter of the furnace of the secondary combustion chamber 18.

[0075] The secondary fuel spray gun has an injection speed of ≤120m / s.

[0076] The secondary air spray gun has a spray speed of ≤110m / s.

[0077] The design of the primary combustion chamber 1, mixing chamber 17, secondary air swirl, and secondary fuel swirl improves combustion stability and solves the problem of poor ignition of ammonia. It also increases the residence time of components in the combustion chamber space, enhances component oxidation, and reduces the emission of unburned gases such as carbon monoxide in the flue gas. During operation, primary air 11 rotates in the primary combustion chamber 1, rapidly mixing with primary fuel 12. Primary fuel 12 rotates along with primary air 11. The igniter ignites the air-fuel mixture in the primary combustion chamber 1. After combustion, the air and fuel in the primary combustion chamber 1 form high-temperature, low-oxygen flue gas, which flows downstream along the primary reaction zone and enters the mixing chamber 17 to mix with secondary air 15 and secondary fuel 16. The secondary air 15 and secondary fuel 16 rotate, heat up, oxidize, and reduce, propelling the flame and conducting combustion heat. Through the above process, ammonia can be fully swirled and mixed within the combustion chamber, where both air and fuel flows rotate, achieving a high level of internal recirculation. This improves the preheating, dilution, and oxidation of reactants, enhancing combustion stability, efficiency, and reducing pollutant emissions. Because ammonia is difficult to ignite, the swirler assembly ensures thorough mixing with air and sufficient time to reach its ignition point. Furthermore, the swirler assembly addresses the issue of easily extinguished ammonia flames. Research shows that oxygen-enriched combustion is more conducive to ammonia combustion. The tangential arrangement of the secondary fuel and air nozzles allows both secondary air and fuel to rotate. The staggered arrangement of the air and fuel nozzles ensures thorough mixing and rotation of air and fuel, forming a vortex. This increases the residence time of ammonia molecules within the chemical reaction space, promoting ammonia oxidation. Simultaneously, the vortex draws in high-temperature, low-oxygen flue gas, enhancing ammonia oxidation in a low-oxygen atmosphere and reducing the formation of fuel-based nitrogen oxides. Additionally, the vortex effectively mixes air and ammonia, stabilizing the ammonia flame.

[0078] Specifically, the mixing chamber 17 and the secondary combustion chamber adopt... Figure 2 The structural scheme shown.

[0079] Figure 2In this invention, the mixing chamber 17 adopts a mixing device structure 26, which includes a main channel, two air nozzles, and two fuel nozzles. The upstream of the main channel is high-temperature flue gas at a certain temperature and pressure. This invention promotes rapid mixing of air, fuel, and the upstream high-temperature flue gas in the mixing device, and also promotes the mixing, ignition, and combustion of the air and fuel injected into the mixing device itself. The flue gas sampling tube 21 adopts a slender cylindrical structure with several small holes at its end, facing the direction of the exhaust flow from the secondary combustion chamber. The flue gas enters the sampling tube through these holes and is then drawn into the flue gas analyzer for component analysis by a pump. Since the drawn-in flue gas is high-temperature, directly entering the analyzer would damage its precision sensors. Therefore, a cooling water jacket 22 is installed, fitted over the outer wall of the slender cylindrical flue gas sampling tube 21. Cold water enters the cooling water jacket 22 and is then discharged through the water outlet 213.

[0080] Figure 2 The dashed rectangular area 30 indicates the blending plane, with the origin of the Cartesian coordinate system located at the center of the blending plane. Figure 1 It can be seen that in the mixing plane, air and fuel flow into the mixing zone at a certain angle, and then... Figure 1 The combustion chamber axis is defined as the z-axis. In a right-handed coordinate system, the x-axis is located at the horizontal centerline of the air nozzle, and the y-axis is located at the centerline of the fuel nozzle. This nozzle arrangement ensures that the emitted hot flue gas mixes with air and fuel simultaneously and rapidly. This facilitates thorough mixing and preparation of high-temperature, low-oxygen reactants before auto-ignition, promoting the ignition, self-sustaining flame, and flame propagation of poorly ignitable ammonia fuel.

[0081] Figure 2 In the mixing device structure 26 shown, the nozzles of secondary air spray gun 1 29 and secondary air spray gun 211 provide swirling air, and the nozzles of secondary fuel spray gun 1 210 and secondary fuel spray gun 212 provide swirling ammonia or mixed ammonia fuel. The air and fuel are mixed, rotated and recirculated with the upstream high-temperature flue gas in the mixing device structure 26, and flow downstream in the quartz glass tube 27.

[0082] The ammonia gas turbine staged combustion device of the present invention improves ammonia combustion efficiency and reduces thermal NOx emissions. Testing by a detection device has proven that the present invention achieves significant technical effects. (For taking flame photographs and OH...) * The chemiluminescence image shows a quartz glass tube 27 used in the combustion zone. The quartz glass tube 27 experiences heat loss through convection and radiation, both of which are detrimental to insulation. Therefore, this invention also wraps insulation cotton around the outer wall of the quartz glass tube 27 to reduce heat loss.

[0083] The primary fuel 12 and air mass flow rate of the upstream primary combustion zone of the mixing device structure 26 are respectively expressed as m f1and m a1 This indicates that the secondary fuel 16 and the air mass flow rate 26 of the mixing device structure 26 are respectively expressed as m f2 and m a2 This indicates that, during the test, the inlet equivalence ratio of the primary combustion zone and the mixing zone of the mixing device structure 26 upstream is equal. SR is defined as the ratio of the reactant mass flow rate of the primary combustion zone and the reactant mass flow rate of the mixing zone of the mixing device structure 26 upstream, and its expression is:

[0084]

[0085] The fuel used in this invention is ammonia or a mixture of ammonia and fuel. The SR was adjusted from 0.67 to 2.3, and the overall equivalence ratio of reactants at the combustion chamber inlet varied between 0.6 and 0.8. During the test, the total air mass flow rate was maintained at 10 g / s. Different overall equivalence ratios of reactants at the combustion chamber inlet were obtained by varying the fuel mass flow rate. The temperature of both fuel and air was 293 K, and the operating pressure was 1 atm.

[0086] In the test, a Canon IXUS 220HS digital camera was used to take a picture of the flame, with the f-mode set to 5.9 and the shutter speed at 1 / 13s.

[0087] OH * Chemiluminescence images were collected by an enhanced ICCD camera 28 (LaVision, 1024×1024 pixels) equipped with a UV lens (UV Nikkor, 105 mm, f / 4.5) and a bandpass interference filter centered at 310 nm with a bandwidth of 10 nm.

[0088] To eliminate dark signals, a background image is captured using a digital camera with a cap 24, with the same integration time and gain for the image under test, and then subtracted from the original image under test.

[0089] In all chemiluminescence experiments, 200 instantaneous images were recorded and their average value was taken. The signal was detected within an exposure time of 60 μs, and the signal-to-noise ratio of the instantaneous images was better than 10:1.

[0090] Exhaust gas was extracted at five radial positions at the combustion zone outlet using a stainless steel water-cooled probe, and then transported through a heating tube to the PEC 304FT flue gas analyzer 23 for the measurement of O2, NO, NO2 and CO.

[0091] O2 concentration is measured using a zirconia sensor, and NOx / CO content is measured using Fourier transform infrared spectroscopy. The instrument's gas concentration measurement error is less than ±1%. This flue gas analyzer measures the species concentration 6 times every 75 seconds and then calculates the average concentration.

[0092] Record the measurement readings when the concentration data of NOx emissions fluctuates within ±0.5ppm and CO emissions fluctuate within ±2ppm.

[0093] To further test the influence of factors such as swirl number on the combustion characteristics of ammonia premixed swirl, an impeller-type swirl burner was used. Swirls were created by blades at a specific angle, and the flow rates of ammonia and air were controlled by a mass flow meter to form premixed gases with different equivalence ratios. A CCD camera was used to capture flame images, and the flame morphology and combustion limits of ammonia under different experimental conditions were studied in detail. The effects of factors such as swirl number and blade number on the characteristics of ammonia swirl flame were obtained, providing a basis for the widespread application of ammonia.

[0094] The analysis of the causes of unstable phenomena such as flashback and oscillation lift provides guidance for using ammonia as an energy source to provide power and protect the burner structure.

[0095] Ammonia and air are fed from gas cylinders through pressure reducing valves and needle valves to the mass flow meter, where the flow rate is controlled to the required level. Then, through an adapter, they form a premixed gas with a certain equivalent ratio. The premixed gas enters from the opposite air inlets on both sides of the bottom of the swirl burner, passes through metal wool and a rectifier plate, and rises evenly. It reaches the impeller and is ignited by an ignition gun to produce a swirling flame. The flame shape is captured by a CCD camera.

[0096] When adjusting the airflow, it should be done slowly to avoid the effects of sudden changes in flow. To facilitate observation and photography of the swirling flame, a cylindrical quartz glass is placed above the impeller.

[0097] As the airflow rate increases and the flame approaches extinction, the inlet velocity of the premixed combustible gas is much greater than the flame propagation velocity, causing the flame to extinguish due to unstable combustion. At this point, the equivalence ratio of the premixed gas is at the lean-burn limit. When the airflow rate decreases to a certain value, the flame lifts and produces unstable up-and-down oscillations due to the excessive ammonia concentration at the impeller outlet. At this point, the equivalence ratio of the premixed gas is at the rich-burn limit.

[0098] Slowly adjust the airflow rate, and when the flame shape shows the corresponding limiting characteristics, record the airflow rate value at this time, calculate the stoichiometric ratio at this time, and thus obtain the lean and rich fuel limits under different experimental conditions.

[0099] When measuring the combustion limit range, the lean-burn limit is the equivalence ratio when the lean-burn is extinguished, and the rich-burn limit is the equivalence ratio when the flame is lifted and produces unstable up-and-down oscillations.

[0100] Figure 3 and Figure 4 The display shows that secondary air is injected directly into the secondary fuel. This direct injection promotes the oxidation of the chemically reactive ammonia fuel, which is beneficial for improving combustion efficiency. (Summary) Figures 5-8 The resulting combustion effect can be seen Figures 5-8 The flame in this system is based on tangential swirl. In tangential swirl, the flame length in the secondary combustion zone is shorter and the brightness is lower because the reactants mainly burn within the mixing zone cavity. Figure 8 Taking the flame under the condition of Φ=0.6 as an example, there is a bright red area in the lower left corner. This is because the 304 stainless steel pipe is heated by the flame in the mixing zone cavity. This indicates that the fuel and air enter the mixing zone cavity tangentially and immediately meet the conditions for combustion and react, because the air jet direction is directly opposite the fuel nozzle outlet. Figure 3 and Figure 4 As shown in the diagram, secondary air provides oxygen, high-temperature flue gas provides heat and active free radicals, and secondary fuel is easily ignited in a "high-temperature and high-oxygen" atmosphere. Figures 5-8 It also shows that the flame brightness of the secondary burner under the Φ=0.5 condition is very low. When the equivalence ratio is low, the time required for fuel oxidation is short, and the main reaction zone is concentrated in the mixing zone cavity. Therefore, the flame in the secondary combustion zone is almost invisible. The flame under tangential swirl is closer to gentle combustion, with a larger flame volume and a more dispersed reaction zone.

[0101] This invention is not only an innovation in the device itself, but also in the field of combustion field testing. By combining camera imaging, enhanced camera imaging, and flue gas sampling and analysis, it obtains images of flame distribution in the combustion zone, OH* component distribution, and the content of oxygen / carbon monoxide / nitrogen oxides in the flue gas. The real-time simultaneous acquisition of multiple features can provide important reference data for ammonia combustion analysis and combustion scheme optimization.

[0102] It should be noted that implementations not shown or described in the accompanying drawings or the main text of the specification are all forms known to those skilled in the art and are not described in detail. Furthermore, the definitions of the various elements above are not limited to the specific structures and shapes mentioned in the embodiments; those skilled in the art can easily modify or substitute them, for example:

[0103] (1) Other structures can be used for the carbon emission reduction combustion device of the ammonia gas turbine, as long as they can perform the same function; (2) This document provides examples of parameters with specific values, but these parameters do not need to be exactly equal to the corresponding values, but can be approximated to the corresponding values ​​within acceptable error tolerances or design constraints; (3) The directional terms mentioned in the embodiments, such as "up", "down", "front", "back", "left", "right", etc., are only for reference to the directions in the accompanying drawings and are not used to limit the scope of protection of the present invention; (4) The above embodiments can be used in combination with each other or with other embodiments based on design and reliability considerations, that is, the technical features of different embodiments can be freely combined to form more embodiments.

[0104] In summary, the ammonia gas turbine carbon emission reduction swirl staged combustion device of the present invention achieves more uniform fuel-air mixing, and the use of axial staged combustion results in a lower peak flame temperature, which is beneficial for optimizing the furnace temperature field and reducing carbon and NOx emissions.

[0105] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A carbon abatement swirled staged combustion device for ammonia gas turbine comprising a primary combustion chamber connected to a head assembly on the front side, characterized in that, It also includes a rapid mixing device and a secondary combustion chamber. The rapid mixing device is connected to the primary combustion chamber and the secondary combustion chamber respectively. The rapid mixing device is equipped with a cyclone assembly. The head assembly at the front of the primary combustion chamber includes a primary fuel injector, a primary air injector, and an air cyclone separator. The primary combustion chamber includes a primary combustion chamber furnace. The primary fuel injector and the primary air injector are connected to the primary combustion chamber furnace through pipes. The primary fuel injector and the primary air injector respectively introduce primary air and primary fuel into the primary combustion chamber furnace. The air cyclone separator is connected to the primary combustion chamber furnace via a pipe; The secondary combustion chamber includes a secondary combustion chamber furnace, which is connected to the flue gas outlet; The primary fuel injector is located at the center of the head assembly, and the cross-sections of the primary fuel injector, the primary air injector, and the bottom surface of the primary combustion chamber are flush. The bottom surface of the primary combustion chamber is connected to multiple primary air spray guns, which are located near the bottom of the furnace and evenly distributed along the circumference. One is a fuel spray gun arranged in the inner ring, and the other is an air spray gun arranged in the outer ring. The rapid mixing device includes a secondary fuel spray gun for introducing secondary fuel, a secondary air spray gun for introducing secondary air, and a mixing chamber. The secondary fuel spray gun and the secondary air spray gun are respectively connected to the mixing chamber through pipes. The NOx emissions generated in the primary combustion chamber enter the secondary combustion chamber and mix with the secondary fuel, which can reduce the NOx emissions from the primary combustion chamber. The secondary fuel spray gun tangentially penetrates the outer wall of the mixing chamber and is welded to ensure that after the secondary fuel enters the mixing chamber, the airflow impacts the inner wall of the mixing chamber, forming a stagnant backflow vortex, which allows the secondary fuel to rotate. The secondary air spray gun tangentially penetrates the outer wall of the mixing chamber and is welded to ensure that after the secondary air enters the mixing chamber, the airflow impacts the inner wall of the mixing chamber, forming a stagnant backflow vortex, which allows the secondary air to rotate.

2. The ammonia gas turbine carbon abatement cyclonic staged combustion device of claim 1, wherein, The diameter of the primary fuel injection gun is not less than 1.8 mm; The diameter of the primary air spray gun shall not be less than 3mm; The diameter of the primary combustion chamber furnace or hydraulic diameter is 10 to 30 times the diameter of the primary air spray gun; The height of the primary combustion chamber furnace is 1 to 5.5 times the diameter of the primary combustion chamber furnace or the hydraulic diameter; The injection speed of the primary fuel injector is ≤120m / s.

3. The ammonia gas turbine carbon abatement swirling staged combustion apparatus of claim 1, wherein, The secondary fuel spray gun adopts a hollow straight cylindrical structure made of high-temperature resistant metal material; the secondary air spray gun adopts a hollow straight cylindrical structure made of high-temperature resistant metal material; the secondary fuel spray gun and the secondary air spray gun enter in the same tangential direction.

4. The ammonia gas turbine carbon emission reduction swirl staged combustion device as described in claim 1, characterized in that, The lower section of the mixing chamber is flush with the top surface of the primary combustion chamber furnace, which serves to seal the primary combustion chamber furnace. The upper section of the mixing chamber is flush with the bottom surface of the secondary combustion chamber furnace, which serves to seal the secondary combustion chamber furnace. The secondary fuel spray gun and the secondary air spray gun are arranged on the outer wall of the mixing chamber, and are evenly spaced in a circular arrangement. The circumferential cross-sections of the secondary fuel spray gun and the secondary air spray gun are at the same height, and the fuel spray gun and air spray gun are arranged alternately. Alternatively, the circumferential cross-sections of the secondary fuel spray gun and the secondary air spray gun do not coincide, and the fuel spray gun and air spray gun are staggered. The secondary fuel and secondary air are jetted and flowed independently, and enter the mixing chamber to mix.

5. The ammonia gas turbine carbon emission reduction swirl staged combustion device as described in claim 4, characterized in that, The secondary fuel spray guns are arranged on the same circumferential cross section. The secondary fuel spray guns enter the mixing chamber tangentially with a tangential angle of not less than 15° and a secondary fuel swirl number of not less than 0.

3. The secondary air spray guns are arranged on the same circumferential cross section. The secondary air spray guns enter the mixing chamber tangentially with a tangential angle of not less than 30° and a secondary air swirl number of not less than 0.

4. The diameter of the secondary fuel spray gun is not less than 1.8 mm; The diameter of the secondary air spray gun is not less than 3mm; The diameter of the mixing chamber or the hydraulic diameter is 10 to 30 times the diameter of the secondary air spray gun; The height of the mixing chamber is 0.1 to 3 times the diameter of the mixing chamber or the hydraulic diameter; The outer diameter of the mixing chamber is the same as the inner diameter of the secondary combustion chamber furnace. The secondary fuel spray gun injection speed is ≤120m / s; The secondary air spray gun has a spray speed of ≤110m / s.

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