A multi-fuel mixing nozzle, combustion chamber and combustion method for a gas turbine

Abstract

The present invention discloses a multi-fuel mixing nozzle, a combustion chamber and a combustion method for a gas turbine, which are applied to the technical field of gas turbines. By arranging the output ends of a fuel gas premixing channel, a fuel gas diffusion channel and a radial fast-mixing air channel in sequence to communicate with a swirling premixed gas output channel within a fuel nozzle body; when burning a fuel gas with low reaction characteristics, the premixed fuel gas containing the fuel gas with low reaction characteristics is mixed with the radial fast-mixing air in the swirling premixed gas output channel and then output, or is successively mixed with the fuel gas with high / low reaction characteristics ejected from the fuel gas diffusion channel and the radial fast-mixing air and then output, so as to achieve stable combustion; when only burning a fuel gas with high reaction characteristics, the fuel gas with high reaction characteristics is output to the swirling premixed gas output channel through the fuel gas diffusion channel, and cross jets with the upstream swirling air and the downstream radial fast-mixing air multiple times, so as to achieve rapid mixing and low-nitrogen combustion.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas turbines, and particularly relates to a multi-fuel mixing nozzle, a combustion chamber and a combustion method for a gas turbine. Background Art

[0002] In the past few decades, the large-scale use of hydrocarbon fuels has generated pollutant emissions such as greenhouse gas CO 2 and NO x resulting in global warming and various environmental pollutions, causing significant and irreversible damage to the ecosystem and posing risks to human survival and health. Therefore, it is crucial to replace traditional fuels to achieve zero carbon emissions. With the accelerating promotion of emission reduction and carbon neutrality in the energy and power industries, the demand for clean alternative fuels in gas turbines is becoming increasingly prominent, which means that the combustion technology of gas turbines must also be correspondingly upgraded, and at the same time, the supporting combustion nozzles and combustion chambers need to be upgraded accordingly.

[0003] Hydrogen is one of the most popular carbon-free fuels and has been widely used in the fuel cell field as a fuel gas with high reaction characteristics. As Figure 1 shown, replacing traditional fuels with hydrogen has greatly reduced the emission intensity of CO 2 . However, hydrogen cannot be found in nature and must be produced, and the high fuel activity is accompanied by flammability and explosiveness; another consideration is the high cost of liquefying hydrogen and transporting liquid hydrogen. This combination of economic and safety factors has hindered the widespread use of hydrogen at present.

[0004] Similarly, as a carbon-free fuel, NH 3 is another effective hydrogen carrier and has a higher hydrogen density than liquid hydrogen per unit volume. In addition, due to more than 100 years of commercial demand, the current large-scale production is very mature; on the other hand, it is easy to liquefy, significantly reducing the storage, transportation and related development costs. However, the low combustion speed and high fuel-type NO x emissions have inhibited the large-scale use of NH 3 , which is specifically manifested in the following aspects:

[0005] (1) Low flame propagation speed: The flame speed of NH 3 at atmospheric pressure and ambient temperature is relatively low, only 7 cm / s, and it is easy to have low combustion efficiency and incomplete combustion;

[0006] (2) High minimum ignition energy: The minimum ignition energy of NH 3 reaches 8 mJ, which is about 40 times that of H 2 , and a relatively high spark energy is required for ignition;

[0007] (3) High ignition temperature: The ignition temperature of NH 3 is higher than that of other common fuels;

[0008] (4) Narrow flammability limit: Compared with H 2 , the flammability limit of NH 3 is much narrower, which may lead to misfire under lean or rich combustion conditions;

[0009] (5) Difficult to start: Given the poor reactivity of ammonia fuel, starting fuel is often required for ignition and starting. For example, Japanese related manufacturers use carbon-containing fuels such as kerosene, diesel, and methane for starting, which not only increases investment but also causes carbon emission problems; while using hydrogen for starting will also increase the system complexity.

[0010] (6) Potential high NO x emissions: Since ammonia fuel contains nitrogen itself, in addition to thermal NO x , more fuel NO x will also be generated, and the unreasonable equivalence ratio distribution in the combustion chamber will also exacerbate this high emission trend.

[0011] With the progress of combustion technology, the roadmap for the use of alternative clean and carbon-free fuels has become roughly clear, that is, at the present stage, while focusing on overcoming the problems of low fuel reactivity and high NO 3 emissions of NH x , it is a priority to develop the use of NH 3 fuel; after solving the problems of large-scale production, storage, and transportation of hydrogen, it will ultimately turn to hydrogen, the ultimate energy source.

[0012] At the same time, it is necessary to realize the differences in energy distribution, extraction, and use among different countries. There are still many uncertainties about alternative clean fuels available for the gas power generation industry, and it is even less likely that there will be only one single fuel in various usage scenarios globally. This means that the flexibility requirement for fuels will be an important design element of new gas turbines, which is more obvious in industries such as petroleum, refining, textile, printing and dyeing, and metallurgy. These scenarios have a huge demand for electricity and steam, while the types of fuels that can be provided are diverse. However, generally, the combustion chamber only supports the combustion of specific fuels, and changing to different fuels will cause a huge difference in the Wobbe index and cannot ensure the release of the same heat load under the same combustion pressure. At the same time, the change in fuel reactivity will lead to changes in the temperature field, and aspects such as combustion stability will be affected. Summary of the Invention

[0013] The technical problem to be solved by the present invention is to provide a multi-fuel mixing nozzle, combustion chamber, and combustion method for a gas turbine to solve the problem that the existing fuel nozzles cannot match the combustion of multiple fuels.

[0014] To solve the above problems, the technical solution of the present invention is as follows:

[0015] A multi-fuel mixing nozzle for a gas turbine according to the present invention includes a fuel nozzle body, and a fuel gas premixing channel, a swirling premixed gas output channel, a fuel gas diffusion channel, and a radial rapid mixing air channel are provided in the fuel nozzle body;

[0016] Along the gas flow direction in the swirling premixed gas output channel, the output ends of the fuel gas premixing channel, the fuel gas diffusion channel, and the radial rapid mixing air channel are sequentially communicated to the swirling premixed gas output channel;

[0017] Wherein, the fuel gas premixing channel is configured to output premixed fuel gas with low-reactivity fuel gas in a premixed manner to the upstream of the swirling premixed gas output channel;

[0018] The fuel gas diffusion channel is configured to output high-reactivity fuel gas or low-reactivity fuel gas in a diffusion manner to the downstream of the swirling premixed gas output channel;

[0019] The output end of the radial rapid mixing air channel is located downstream of the output end of the fuel gas diffusion channel, and the radial rapid mixing air channel is configured to output radial rapid mixing air to the swirling premixed gas output channel.

[0020] For the multi-fuel mixing nozzle for a gas turbine according to the present invention, at least part of the swirling premixed gas output channel is configured to gradually decrease in diameter along the gas flow direction to accelerate the gas flow rate therein.

[0021] For the multi-fuel mixing nozzle for a gas turbine according to the present invention, the fuel gas premixing channel includes a premixed fuel gas channel and a premixed air channel;

[0022] The interval between adjacent swirling vanes on the fuel nozzle body forms the premixed air channel. The premixed fuel gas channel is configured to extend within the swirling vanes and spray from the surface of the swirling vanes, and output low-reactivity fuel gas toward the premixed air channel; the swirling vanes are configured to guide the premixed air entering the premixed air channel to be premixed with the low-reactivity fuel gas to form the premixed fuel gas, and output it into the swirling premixed gas output channel to be converted into a radial swirling form or an axial swirling form.

[0023] For the multi-fuel mixing nozzle for a gas turbine according to the present invention, the swirling vanes can adopt radial swirling vanes or axial swirling vanes.

[0024] The multi-fuel mixing nozzle for a gas turbine according to the present invention, the output end of the fuel gas diffusion channel is communicated with the downstream of the swirling premixed gas output channel through a plurality of discretely arranged fuel gas diffusion injection holes; the output end of the radial rapid mixing air channel is communicated with the swirling premixed gas output channel through a plurality of discretely arranged radial rapid mixing air channel injection ports, and the radial rapid mixing air channel injection ports are located downstream of the fuel gas diffusion injection holes and are arranged in a circumferential dislocation along the swirling direction.

[0025] The multi-fuel mixing nozzle for a gas turbine according to the present invention, the low-reactivity fuel gas is ammonia or methane or synthesis gas with a low hydrogen content.

[0026] The multi-fuel mixing nozzle for a gas turbine according to the present invention, the high-reactivity fuel gas is hydrogen or synthesis gas with a high hydrogen content.

[0027] A multi-fuel combustor based on the combustion of ammonia-based low-reactivity fuel according to the present invention, comprising a combustion chamber and the multi-fuel mixing nozzle for a gas turbine according to any one of the above installed in the combustion chamber;

[0028] A combustion region extending axially is provided in the combustion chamber, and the combustion region includes a rich combustion region, a reburning region and a burnout dilution region arranged axially in sequence;

[0029] The multi-fuel mixing nozzle is configured to output a rich combustion mixed fuel gas of a rich combustion fuel flow and a rich combustion air flow towards the rich combustion region and / or output a reburning mixed fuel gas of a reburning fuel flow and a reburning air flow towards the reburning region;

[0030] Wherein, the rich combustion air flow accounts for 5% to 25% of the total air volume, the reburning air flow accounts for 15% to 30% of the total air volume, and the burnout dilution air flow entering the burnout dilution region accounts for 45% to 80% of the total air volume.

[0031] In the multi-fuel combustor based on the combustion of ammonia-based low-reactivity fuel according to the present invention, the rich combustion fuel flow and the reburning fuel flow are ammonia-based low-reactivity fuel gas, the rich combustion fuel flow accounts for 70% to 100% of the total amount of ammonia-based low-reactivity fuel gas, corresponding to a rich combustion state with a head equivalence ratio between 1 and 2, and the reburning fuel flow accounts for 0% to 30% of the total amount of ammonia-based low-reactivity fuel gas;

[0032] The ammonia-based low-reactivity fuel gas is configured to enter the swirling premixed gas output channel via the fuel gas premixing channel and / or the fuel gas diffusion channel.

[0033] The multi-fuel combustor based on the combustion of ammonia-based low-reactivity fuels of the present invention, wherein the rich fuel stream and the reburn fuel stream are hydrogen-based highly reactive fuel gases, the rich fuel stream accounts for 5% to 25% of the total amount of hydrogen-based highly reactive fuel gases, and the reburn fuel stream accounts for 95% to 75% of the total amount of hydrogen-based highly reactive fuel gases;

[0034] The hydrogen-based highly reactive fuel gas is configured to enter the swirling premixed gas output channel via the fuel gas diffusion channel.

[0035] In the multi-fuel combustor based on the combustion of ammonia-based low-reactivity fuels of the present invention, after determining the distribution ratios of air and ammonia-based low-reactivity fuel gas in the rich combustion region, reburn region, and burnout dilution region of the combustor based on ammonia-based low-reactivity fuels, the hydrogen-based highly reactive fuel gas or other low-reactivity fuel gases are introduced into the combustor through the nozzle fuel gas diffusion channel to achieve multi-fuel co-combustion.

[0036] A combustor of the present invention includes at least one multi-fuel mixing nozzle for a gas turbine as described in any one of the above.

[0037] It further includes:

[0038] A combustion chamber, in which a combustion region extending axially is provided, and the combustion region includes a rich combustion region, a reburn region, and a burnout dilution region arranged axially in sequence;

[0039] A fuel gas channel configured to output a rich fuel stream and a reburn fuel stream;

[0040] An air channel configured to split the total air flow therein and output a rich combustion air flow, a reburn air flow, and a burnout dilution air flow;

[0041] Wherein, the rich fuel stream is configured to be mixed with the rich combustion air flow in the multi-fuel mixing nozzle to form a rich combustion mixture, and the rich combustion mixture is output to the rich combustion region and ignited for rich combustion; the reburn fuel stream is configured to be mixed with the reburn air flow in the multi-fuel mixing nozzle to form a reburn mixture, and the reburn mixture is output to the reburn region to co-combust with the low-reactivity fuel gas escaping from the rich combustion region; the burnout dilution air flow is configured to be output to the burnout dilution region to combust with the unburned low-reactivity fuel gas entering the burnout dilution region.

[0042] In the combustor of the present invention, the multi-fuel mixing nozzles in the rich combustion region and the reburn region are arranged at different axial depths along the combustion chamber.

[0043] For the combustion chamber of the present invention, the multi-fuel mixing nozzles in the rich combustion region and the reburning region are arranged in a stepped manner along the radial direction of the combustion chamber.

[0044] A combustion method of the present invention is applied to a combustion chamber including the multi-fuel mixing nozzle for a gas turbine described in any one of the above, or to the combustion chamber described in any one of the above. The method is as follows:

[0045] A rich combustion region, a reburning region, and a burnout dilution region are arranged in sequence along the axial direction in the combustion chamber;

[0046] Input a rich combustion mixture formed by a rich combustion fuel flow and a rich combustion air flow into the rich combustion region, input a reburning mixture formed by a reburning fuel flow and a reburning air flow into the reburning region, and input a burnout dilution air flow into the burnout dilution region;

[0047] Wherein, the fuel quantity of the rich combustion fuel flow accounts for 70% to 100% of the sum of the fuel quantities of the rich combustion fuel flow and the reburning fuel flow;

[0048] The sum of the air quantities of the rich combustion air flow, the reburning air flow, and the burnout dilution air flow is the total air quantity. The air quantity of the rich combustion air flow accounts for 5% to 25% of the total air quantity, and the air quantity of the reburning air flow accounts for 15% to 30% of the total air quantity.

[0049] Due to the adoption of the above technical solutions, the present invention has the following advantages and positive effects compared with the prior art:

[0050] First, in an embodiment of the present invention, a fuel gas premixing channel, a swirling premixed gas output channel, a fuel gas diffusion channel, and a radial fast-mixing air channel are arranged in the fuel nozzle body. The output ends of the fuel gas premixing channel, the fuel gas diffusion channel, and the radial fast-mixing air channel are sequentially connected to the swirling premixed gas output channel; when burning a fuel gas with low reaction characteristics, the premixed fuel gas containing the fuel gas with low reaction characteristics is mixed with the radial fast-mixing air in the swirling premixed gas output channel and output, or is successively mixed with the fuel gas with high / low reaction characteristics ejected from the fuel gas diffusion channel and the radial fast-mixing air and output to achieve stable combustion; when only burning a fuel gas with high reaction characteristics, the fuel gas with high reaction characteristics is output to the swirling premixed gas output channel through the fuel gas diffusion channel, and is cross-jet with the upstream swirling air and the downstream radial fast-mixing air multiple times to achieve rapid mixing and low-nitrogen combustion; so that the multi-fuel mixing nozzle can burn low-reaction-characteristic fuel gases such as NH 3 alone, and can also burn high-reaction-characteristic fuel gases such as H 2 alone, or can burn low-reaction-characteristic fuel gases and high-reaction-characteristic fuel gases simultaneously, improving the fuel flexibility.

[0051] II. In one embodiment of the present invention, the space in the combustion chamber is divided into a rich combustion region, a reburning region, and a burnout dilution region that extend sequentially. The fuel gas premixing channel is configured to output a rich combustion fuel stream and a reburning fuel stream, and the air channel is configured to output a rich combustion air stream, a reburning air stream, and a burnout dilution air stream. The rich combustion fuel stream and the rich combustion air stream are mixed and output to the rich combustion region, and the reburning fuel stream and the reburning air stream are mixed and output to the reburning region, and the proportions of each fuel stream and each air stream are adjusted; such that the equivalence ratio in the rich combustion region where most of the NH 3 fuel is involved is controlled close to the upper limit of the flammable limit, so that NO x emissions are greatly reduced, and then the reburning mixed flow is added downstream in a relay manner. The equivalence ratio in the reburning region is controlled near the lower limit of the flammable limit, thereby effectively controlling the cumulative nitrogen oxide emissions at the outlet, keeping the emissions within an acceptable low range, and ensuring stable combustion and burnout at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 is a schematic diagram showing the influence of the H 4 content in the fuel on the CO 2 emission intensity; 2

[0053] Figure 2 is a schematic diagram of the multi-fuel rapid mixing nozzle according to Embodiment 1 of the present invention;

[0054] Figure 3 is a cross-sectional view of the multi-fuel rapid mixing nozzle according to Embodiment 1 of the present invention;

[0055] Figure 4 is another cross-sectional view of the multi-fuel rapid mixing nozzle according to Embodiment 1 of the present invention;

[0056] Figure 5 is the A-A cross-sectional view of the multi-fuel rapid mixing nozzle according to Embodiment 1 of the present invention;

[0057] Figure 6 is the B-B cross-sectional view of the multi-fuel rapid mixing nozzle according to Embodiment 1 of the present invention;

[0058] Figure 7 is the C-C cross-sectional view of the multi-fuel rapid mixing nozzle according to Embodiment 1 of the present invention;

[0059] Figure 8 is the D-D cross-sectional view of the multi-fuel rapid mixing nozzle according to Embodiment 1 of the present invention;

[0060] Figure 9 is the E-E cross-sectional view of the multi-fuel rapid mixing nozzle according to Embodiment 1 of the present invention;

[0061] Figure 10 ​It is a cross-sectional view of the combustion chamber according to the second embodiment of the present invention;

[0062] Figure 11 It is another cross-sectional view of the combustion chamber according to the second embodiment of the present invention;

[0063] Figure 12 It is a schematic structural diagram of the hood of the combustion chamber according to the second embodiment of the present invention;

[0064] Figure 13 It is for NH 3 Schematic diagram of the influence of the change of the equivalence ratio on the outlet flue gas components in the atmospheric pressure premixed combustion;

[0065] Figure 14 It is a schematic diagram of the multi-stage combustion technology of the combustion chamber according to the third and fourth embodiments of the present invention;

[0066] Figure 15 It is a cross-sectional view of the structure of the combustion chamber according to the third and fourth embodiments of the present invention;

[0067] Figure 16 It is a cross-sectional view of the structure of the combustion chamber according to the fifth embodiment of the present invention;

[0068] Figure 17 It is a schematic diagram of the principle of the combustion chamber according to the third embodiment of the present invention.

[0069] Explanation of reference numerals: 1. Multi-fuel mixing nozzle; 1A. Rich combustion region nozzle; 1B. Reburning zone nozzle; 1-1. Fuel gas diffusion channel inlet pipe; 1-2. Fuel gas diffusion channel radial diffusion pipe; 1-3. Fuel gas diffusion channel axial conveying pipe; 1-4. Fuel gas diffusion channel radial return pipe; 1-5. Annular fuel gas output channel; 1-6. Fuel gas diffusion injection hole; 1-7. Premixed fuel gas channel inlet pipe; 1-8. Premixed fuel gas channel axial sandwich channel; 1-9. Premixed fuel gas channel radial diffusion pipe; 1-10. Premixed fuel gas channel axial conveying pipe; 1-11. Premixed fuel gas channel injection hole; 1-12. Fast mixing air radial conveying pipe; 1-13. Fast mixing air axial conveying pipe; 1-14. Radial fast mixing air channel injection port; 1-15. Swirl vane; 1-16. Tangential air channel; 1-17. Swirl premixed gas output channel; 1-18. Nozzle tapered outer wall; 2. Outer casing; 3. Fairing; 4. Hood; 4-1. Upstream wall surface; 4-2. Impingement cooling hole; 4-3. Downstream wall surface; 4A. Central hood; 4B. Annular hood; 5. Combustion liner; 5-1. Mixing hole; 6. Combustion chamber end cover; 7. Rich combustion fuel flow; 8. Rich combustion air flow; 9. Reburning fuel flow; 10. Reburning air flow; 11. Burnout dilution air flow. Detailed implementation manners

[0070] The following further elaborates on a multi-fuel mixing nozzle, a combustion chamber, and a combustion method for a gas turbine proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer.

[0071] Embodiment 1

[0072] Refer to Figures 2 to 9 , in one embodiment, a multi-fuel mixing nozzle 1 for a gas turbine includes a fuel nozzle body. Inside the fuel nozzle body, there are a swirl premixed gas output channel 1-17, a fuel gas premixing channel, a fuel gas diffusion channel, and a radial rapid mixing air channel. Along the gas flow direction (from upstream to downstream) inside the swirl premixed gas output channel, the output ends of the fuel gas premixing channel, the fuel gas diffusion channel, and the radial rapid mixing air channel are sequentially connected to the swirl premixed gas output channel 1-17.

[0073] Among them, the fuel gas premixing channel is configured to output premixed fuel gas with low-reactivity fuel gas (such as NH 3 , low-hydrogen-content synthesis gas, CH 4 ) to the upstream of the swirl premixed gas output channel 1-17. The fuel gas diffusion channel is configured to output low-reactivity fuel gas (such as NH 3 , low-hydrogen-content synthesis gas, CH 4 ) or high-reactivity fuel gas (such as H 2 , high-hydrogen-content synthesis gas) to the downstream of the swirl premixed gas output channel 1-17 in a diffusive manner (the diffusive manner means non-premixed, indicating that the fuel and air are not pre-mixed, and the two adopt a combustion method of mixing and burning while being fed into the gas region, which is the corresponding fuel gas directly output towards the inside of the swirl premixed gas output channel 1-17 here). The output end of the radial rapid mixing air channel is located downstream of the output end of the fuel gas diffusion channel (specifically, it can be set at the outlet of the swirl premixed gas output channel 1-17), and the radial rapid mixing air channel is configured to output radial rapid mixing air to the swirl premixed gas output channel 1-17.

[0074] In this embodiment, a swirl premixed gas output channel 1-17, a fuel gas premixing channel, a fuel gas diffusion channel, and a radial fast mixing air channel are arranged inside the fuel nozzle body. The output ends of the fuel gas premixing channel, the fuel gas diffusion channel, and the radial fast mixing air channel are sequentially connected to the swirl premixed gas output channel. The fuel gas premixing channel outputs premixed fuel gas containing low-reactivity fuel gas to the upstream of the swirl premixed gas output channel 1-17. The fuel gas diffusion channel outputs low-reactivity fuel gas or high-reactivity fuel gas to the downstream of the swirl premixed gas output channel 1-17. The radial fast mixing air channel outputs radial fast mixing air to the swirl premixed gas output channel 1-17 and is located downstream of the output end of the fuel gas diffusion channel, and is slightly misaligned in the circumferential direction along the swirl direction to achieve cross jet of the diffused fuel;

[0075] When burning low-reactivity fuel gas, the premixed fuel gas containing low-reactivity fuel gas is mixed with the radial fast mixing air in the swirl premixed gas output channel and output, or is successively mixed with the high / low-reactivity fuel gas ejected from the fuel gas diffusion channel and the radial fast mixing air and output to achieve stable combustion; when only burning high-reactivity fuel gas, the high-reactivity fuel gas is output to the swirl premixed gas output channel through the fuel gas diffusion channel, and multiple cross jets occur with the upstream swirl air and the downstream radial fast mixing air to achieve rapid mixing and low-nitrogen combustion; enabling the multi-fuel mixing nozzle to burn low-reactivity fuel gases such as NH 3 alone, and can also burn high-reactivity fuel gases such as H 2 alone, or can burn low-reactivity fuel gas and high-reactivity fuel gas simultaneously, greatly broadening the types of applicable fuels and enhancing fuel flexibility.

[0076] The specific structure of the multi-fuel mixing nozzle for a gas turbine in this embodiment will be further described below:

[0077] In this embodiment, at least part of the swirl premixed gas output channel is configured to gradually decrease in diameter along the gas flow direction, so that the gas flow velocity of the premixed fuel gas and / or the high-reactivity fuel gas entering it is gradually accelerated to accelerate mixing. Specifically, the swirl premixed gas output channel may include an annular mixing section and an annular tapered section that are sequentially connected along the flow direction. At least part of the annular tapered section is configured to gradually decrease in diameter along the gas flow direction. The premixed fuel gas may be configured to be input into the annular mixing section, and the fuel gas of the fuel gas diffusion channel may be configured to be input into the annular mixing section and / or the annular tapered section, so that the premixed fuel gas and the diffused fuel gas can be gradually accelerated in the annular tapered section and mixed more evenly. Among them, the swirl premixed gas output channel may specifically be an annular space formed between the nozzle tapered outer wall 1-18 on the outside and the inner solid part of the fuel nozzle body on the inside.

[0078] Further, the above-mentioned premixed fuel gas may specifically be set to be injected tangentially into the swirling premixed gas output channel (annular mixing section), and spiral axially in the annular mixing section towards the downstream, that is, the annular mixing section receives the swirling mixed gas and transforms it into a premixed fuel gas with an axially spiral motion towards the annular tapered section for output.

[0079] See Figure 8 、 Figure 9 , in this embodiment, the fuel gas premixing channel may specifically include a premixed air channel and a premixed fuel gas channel. Among them, the intervals between adjacent swirling vanes 1-15 on the fuel nozzle body form the premixed air channel, and the premixed fuel gas channel is configured to extend within the swirling vanes and be ejected from the surface of the swirling vanes 1-15 to output low-reactivity fuel gas towards the premixed air channel. The swirling vanes 1-15 are configured to guide the premixed air entering the premixed air channel to premix with the low-reactivity fuel gas to form a premixed fuel gas, and output it into the swirling premixed gas output channel to be transformed into a radial swirling form or an axial swirling form.

[0080] Specifically, the premixed air channel may be a plurality of tangential air channels 1-16 that are circumferentially spaced and opened on the fuel nozzle body (the circumferential spacing is achieved by the swirling vanes). The tangential air channels 1-16 are axially discretely distributed on the fuel nozzle body, and the airflow direction of the tangential air channels 1-16 is tangent to the annular mixing section. The tangential air channels 1-16 are used to guide the outer air to enter the nozzle tangentially and stir up the flow field to form swirling air. The nozzle solid part between adjacent tangential air channels 1-16 is the swirling vane 1-15 in an asymmetric fan shape. Among them, the swirling vanes 1-15 can adopt radial swirling vanes or axial swirling vanes.

[0081] Further, the premixed fuel gas channel includes a premixed fuel gas channel input section and a plurality of premixed fuel gas channel output sections that are connected in sequence.

[0082] The plurality of premixed fuel gas channel output sections may specifically be premixed fuel gas channel axial delivery pipes 1-10. Each premixed fuel gas channel axial delivery pipe 1-10 corresponds to at least one tangential air channel 1-16, and each premixed fuel gas channel axial delivery pipe 1-10 is connected to the tangential air channel 1-16 through a plurality of premixed fuel gas channel injection holes 1-11 that are axially spaced. That is, the premixed fuel gas channel output section is opened within the swirling vane 1-15, and the premixed fuel gas channel injection holes 1-11 are also opened within the swirling vane 1-15. Among them, the premixed fuel gas channel axial delivery pipes 1-10 can be respectively connected to two corresponding tangential air channels 1-16 on both sides through the premixed fuel gas channel injection holes 1-11, and the premixed fuel gas channel injection holes 1-11 can be arranged to be discretely and evenly distributed along the height direction of the swirling vane 1-15, and are thus used to inject the fuel gas towards the two tangential air channels 1-16 on both sides.

[0083] The input section of the premixed fuel gas channel may include a premixed fuel gas channel inlet pipe 1-7, a premixed fuel gas channel axial sandwich channel 1-8, and several premixed fuel gas channel radial diffusion pipes 1-9. The premixed fuel gas channel inlet pipe 1-7 may be arranged radially on the combustion nozzle body. The premixed fuel gas channel axial sandwich channel 1-8 is an annular intermediate channel opened in the combustion nozzle body. One end of this annular intermediate channel is connected to the premixed fuel gas channel inlet pipe 1-7, and the other end is respectively connected to several premixed fuel gas channel radial diffusion pipes 1-9 extending radially in the combustion nozzle body. The ends of the premixed fuel gas channel radial diffusion pipes 1-9 are respectively connected to the premixed fuel gas channel axial delivery pipes 1-10.

[0084] In this embodiment, the fuel gas diffusion channel may specifically include an input section of the fuel gas diffusion channel, several bent sections of the fuel gas diffusion channel, and an output section of the fuel gas diffusion channel. The several bent sections of the fuel gas diffusion channel are respectively arranged at intervals in the circumferential direction, and both ends of each bent section of the fuel gas diffusion channel are respectively connected to the input section of the fuel gas diffusion channel and the output section of the fuel gas diffusion channel. The output section of the fuel gas diffusion channel is located inside the annular mixing section and the annular tapered section, and the end of the output section of the fuel gas diffusion channel is connected to the annular tapered section through several fuel gas diffusion injection holes 1-6 arranged at intervals in the circumferential direction, that is, the fuel gas is ejected radially outward.

[0085] Specifically, the input section of the fuel gas diffusion channel is the fuel gas diffusion channel inlet pipe 1-1, the bent section of the fuel gas diffusion channel is the sequentially connected fuel gas diffusion channel radial diffusion pipe 1-2, the fuel gas diffusion channel axial delivery pipe 1-3, and the fuel gas diffusion channel radial return pipe 1-4. The output section of the fuel gas diffusion channel is the annular fuel gas output channel 1-5. The fuel gas enters from the fuel gas diffusion channel inlet pipe 1-1, and then enters each fuel gas diffusion channel radial diffusion pipe 1-2 and is delivered radially outward to the fuel gas diffusion channel axial delivery pipe 1-3 for axial delivery, and then enters the fuel gas diffusion channel radial return pipe 1-4 and is delivered radially inward. The fuel gas in each fuel gas diffusion channel radial return pipe 1-4 converges in the annular fuel gas output channel 1-5 and is ejected radially outward through the fuel gas diffusion injection holes 1-6 thereon. Among them, the design of the bent section device of the fuel gas diffusion channel as a return and repeated channel is for structural layout needs on the one hand, and on the other hand, while achieving the purpose of inner layer diffusion fuel supply, through the folded delivery, the pressure gradient between the areas near the fuel gas diffusion injection holes 1-6 is reduced, and the uniformity of the incident fuel is improved.

[0086] In this embodiment, the radial rapid mixing air channel includes a plurality of inner rapid mixing air input sections and inner rapid mixing air output sections. The inner rapid mixing air output section is located inside the output section of the fuel gas diffusion channel. A plurality of inner rapid mixing air input sections penetrate through the fuel nozzle body and communicate with the inner rapid mixing air output section, and the plurality of inner rapid mixing air input sections are arranged staggeredly with the bent section of the fuel gas diffusion channel.

[0087] Among them, the inner rapid mixing air input section can specifically be the rapid mixing air radial conveying pipe 1-12, and the inner rapid mixing air output section can specifically be the rapid mixing air axial conveying pipe 1-13. A plurality of radial rapid mixing air channel injection ports 1-14 are arranged at intervals in the circumferential direction at the end of the rapid mixing air axial conveying pipe 1-13. The radial rapid mixing air channel injection port 1-14 is located downstream of the annular tapered section in the axial direction. The rapid mixing air radial conveying pipe 1-12 is arranged in the area corresponding to the bent section of the fuel gas diffusion channel and is misaligned with it. External air enters the rapid mixing air axial conveying pipe 1-13 radially from the rapid mixing air radial conveying pipe 1-12 and converges, and then moves in the rapid mixing air axial conveying pipe 1-13 and is conveyed to the radial rapid mixing air channel injection port 1-14 at the end, and is output radially outward from the radial rapid mixing air channel injection port 1-14. Among them, the radial rapid mixing air channel injection port 1-14 is located downstream of the fuel gas diffusion injection hole 1-6 and can be arranged to be staggered in the circumferential direction along the swirling direction, that is, the ejection direction of the radial rapid mixing air channel injection port 1-14 is not tangent to the rotation direction of the helically advancing fuel at the annular tapered section, so as to achieve cross jet and make the mixing more uniform.

[0088] In this embodiment, for low-reactivity fuel gas represented by NH 3 The low-reactivity fuel gas enters from the premixed fuel gas channel, or enters from the fuel gas diffusion channel and the premixed fuel gas channel at the same time. The low-reactivity fuel gas and air in the premixed fuel gas channel complete the first "cross jet" in the tangential air channel 1-16, and are tangentially injected into the annular mixing section while mixing, completing the swirling of the flow field, and at the same time, the movement direction is changed from tangential to axially helically rotating forward. Near the nozzle outlet, as the channel tapers, the mixture gas is accelerated, the turbulent kinetic energy increases, and the mixing becomes more uniform. Further downstream of the nozzle, a pilot diffusion combustion is organized (that is, the fuel gas output through the fuel gas diffusion injection hole 1-6, and the fuel gas here can be low-reactivity fuel gas or high-reactivity fuel gas), which plays an important supporting role in ignition start and stable combustion, but from the perspective of reducing NO xFrom the perspective of emission, it is also undesirable to have a local high equivalence ratio area. For this reason, a radial fast-mixing air channel injection port 1-14 is arranged downstream of the fuel gas diffusion injection port 1-6. In this way, the low-reactivity fuel gas or high-reactivity fuel gas ejected from the fuel gas diffusion injection port 1-6 completes the second "cross jet" with the mixed gas in the annular tapered section. After completing the exchange momentum and rapid mixing, it collides vertically with the radial fast-mixing air output from the radial fast-mixing air channel injection port 1-14 to complete the third "cross jet". In this way, after three "cross jets", the swirl field is established and the mixing process is quickly completed.

[0089] For H 2 The fuel is a highly reactive fuel gas represented by the fuel. To prevent nozzle flashback, the fuel can be set to enter only from the fuel gas diffusion channel.

[0090] Similarly, the fuel gas ejected from the fuel gas diffusion injection hole 1-6 completes the first "cross jet" with the air in the annular tapered section, and after completing the exchange momentum and rapid mixing, it collides vertically with the radial fast mixing air channel injection port 1-14 to complete the second "cross jet". In this arrangement, after the second "cross jet", the swirl field is established and the mixing process is quickly completed.

[0091] Preferably, CH 4 As an active comparison fuel, it is more active than CH 4 The fuel gas with high reactivity is considered as high reactivity fuel gas, and the fuel gas with low reactivity is considered as low reactivity fuel gas. The feed arrangement of common fuels is as follows:

[0092]

[0093] The multi-fuel mixing nozzle for a gas turbine of this embodiment is based on NH 3 Designed for combustion needs, while also being able to burn CH 4 , H 2 and various synthetic gas fuels, greatly broadening the types of applicable fuels. In addition, the two cross jets of axial swirl air and fuel, and radial fast mixing air and upstream mixed gas, greatly promote the rapid and full mixing of fuels.

[0094] Embodiment 2

[0095] See also Figures 10 to 12 The present embodiment provides a combustion chamber, comprising the multi-fuel mixing nozzle 1 for a gas turbine in the above-mentioned embodiment 1.

[0096] The combustion chamber further comprises a fairing 3, a cap 4 and a flame tube 5 which are sequentially connected along the axial direction. The side of the cap 4 facing the inner cavity of the fairing 3 is an air surface, and the side of the cap 4 facing the inner cavity of the flame tube 5 is a combustion surface.

[0097] The cowl 4 is configured to have a gradually increasing axial diameter and form a small-diameter end and a large-diameter end in the axial direction (i.e., the cowl 4 is in an overall frustum shape, and its cross-section is trapezoidal). The multi-fuel mixing nozzle 1 is installed at the small-diameter end, and the fairing 3 and the flame tube 5 are respectively installed at the large-diameter end. The cowl 4 is provided with a cooling channel communicating the air side and the combustion side at the large-diameter end.

[0098] Further, the cowl 4 includes an upstream wall surface 4-1 and a downstream wall surface 4-3 that are parallel and spaced apart. The upstream wall surface 4-1 is respectively connected to the fairing 3 and the flame tube 5. The gap between the peripheral edge of the downstream wall surface 4-3 and the flame tube 5 is the cooling channel. Among them, the upstream wall surface 4-1 is provided with a number of penetrating impingement cooling holes 4-2. The air in the fairing 3 enters the flame tube 5 through the impingement cooling holes 4-2, the space between the upstream wall surface 4-1 and the downstream wall surface 4-3, and the cooling channel.

[0099] That is, the cowl 4 is arranged as a double-wall structure, gradually expanding and arranged downstream of the fairing 3 and the nozzle. The air in the fairing 3 enters the gap between the double walls through the impingement cooling holes 4-2, and then is output through the annular cooling channel between the flame tube 5 and the downstream wall surface 4-3. The swirling incoming gas (mixed fuel gas) of the multi-fuel mixing nozzle 1 will form a recirculation vortex downstream, and a recirculation vortex with the opposite swirling direction (cooling air) will also be formed in the vicinity of the connection between the cowl 4 and the flame tube 5, forming a recirculation zone at the shoulder of the combustion chamber, promoting the circulation of flue gas inside the combustion chamber, and achieving the dual effects of stable combustion and emission reduction.

[0100] Further, an outer casing 2 can be sleeved outside the flame tube 5 and the fairing 3. The space between the outer casing 2 and the flame tube 5 and the fairing 3 is the air input channel. The flame tube 5 can be provided with mixing holes 5-1 communicating with the air input channel, and the mixing holes 5-1 are arranged at intervals in the circumferential direction.

[0101] The combustion chamber of this embodiment can achieve a relatively low level of NO x emission when burning fuels with a high hydrogen content: By quickly and fully mixing, the local high equivalence ratio is reduced, and thus the maximum combustion temperature; at the same time, a nozzle with a gradually shrinking outlet is used, combined with the gradually expanding cowl 4, to form a recirculation zone at the shoulder of the combustion chamber, promoting the circulation of flue gas inside the combustion chamber and achieving the dual effects of stable combustion and emission reduction.

[0102] Embodiment Three

[0103] See Figures 13 to 15 and Figure 17, this embodiment provides a multi-fuel combustor based on the combustion of ammonia-based low-reactivity fuels, including a combustion chamber and the multi-fuel mixing nozzle for a gas turbine in the first embodiment above. The multi-fuel mixing nozzle is installed in the combustion chamber. An axially extending combustion region is provided in the combustion chamber, and the combustion region includes a rich combustion region, a reburning region, and a burnout dilution region arranged axially in sequence.

[0104] The multi-fuel mixing nozzle is configured to output a rich combustion mixed fuel gas of a rich combustion fuel stream 7 and a rich combustion air stream 8 toward the rich combustion region and / or a reburning mixed fuel gas of a reburning fuel stream 9 and a reburning air stream 10 toward the reburning region.

[0105] Among them, the rich combustion air stream 8 accounts for 5% to 25% of the total air volume, the reburning air stream 10 accounts for 15% to 30% of the total air volume, and the burnout dilution air stream 11 entering the burnout dilution region accounts for 45% to 80% of the total air volume.

[0106] Since the air inlet ratio at each part of the combustor cannot be adjusted after the design is completed, the only thing that can be adjusted is the fuel inlet ratio at each part of the combustor. Therefore, in this embodiment, through the design of the multi-fuel mixing nozzle, the air inlet ratio of the combustor can meet the combustion of ammonia-based low-reactivity fuel gas while also meeting the combustion of hydrogen-based highly reactive fuel gas.

[0107] Under the combustion requirement of ammonia-based low-reactivity fuel gas, both the rich combustion fuel stream 7 and the reburning fuel stream 9 are ammonia-based low-reactivity fuel gas. Set the ratio of the two as follows: the rich combustion fuel stream 7 accounts for 70% to 100% of the total amount of ammonia-based low-reactivity fuel gas, corresponding to a rich combustion state with a head equivalence ratio between 1 and 2, and the reburning fuel stream 9 accounts for 0% to 30% of the total amount of ammonia-based low-reactivity fuel gas. And the ammonia-based low-reactivity fuel gas is set to enter the swirling premixed gas output channel through the fuel gas premixing channel and / or the fuel gas diffusion channel, and then achieve stable combustion of the ammonia-based low-reactivity fuel gas in the combustor through the way of premixed / diffusion combustion.

[0108] Under the combustion requirement of hydrogen-based highly reactive fuel gas, both the rich combustion fuel stream 7 and the reburning fuel stream 9 are hydrogen-based highly reactive fuel gas. Set the ratio of the two as follows: the rich combustion fuel stream 7 accounts for 5% to 25% of the total amount of hydrogen-based highly reactive fuel gas, and the reburning fuel stream 9 accounts for 95% to 75% of the total amount of hydrogen-based highly reactive fuel gas. And the hydrogen-based highly reactive fuel gas is set to enter the swirling premixed gas output channel through the fuel gas diffusion channel, and then achieve stable combustion of the hydrogen-based highly reactive fuel gas in the combustor through the way of diffusion combustion.

[0109] Furthermore, after determining the distribution ratio of air and ammonia low-reactivity fuel in the rich combustion area, reburning area and burnout dilution area of ​​the combustion chamber based on the ammonia low-reactivity fuel, this embodiment can further introduce hydrogen high-reactivity fuel gas or other low-reactivity fuel gas from the nozzle fuel gas diffusion channel of the multi-fuel mixing nozzle (for example, on the basis of introducing ammonia low-reactivity fuel gas into the fuel gas premixing channel, methane and other low-reactivity fuel gases are introduced into the fuel gas diffusion channel. The two parts of low-reactivity fuel gas, one part is diffused and the other part is premixed, which can improve flame stability), thereby realizing multi-fuel co-firing.

[0110] Embodiment 4

[0111] See also Figures 13 to 15 In one embodiment, a combustion chamber can be used for multi-stage combustion of ammonia, including a combustion chamber, a fuel-gas premixing channel, an air channel, and the multi-fuel mixing nozzle 1 in the above-mentioned embodiment 1.

[0112] A combustion zone extending in the axial direction is provided in the combustion chamber, and the combustion zone includes a rich fuel zone, a reburning zone and a burnout dilution zone arranged in sequence in the axial direction. The fuel gas premixing channel is configured to output a rich fuel flow 7 and a reburning fuel flow 9. The air channel is configured to split the total air flow therein and output a rich air flow 8, a reburning air flow 10 and a burnout dilution air flow 11.

[0113] The rich fuel flow 7 is configured to be mixed with the rich air flow 8 through the multi-fuel mixing nozzle 1 to form a rich mixture, which is output to the rich region and ignited for rich combustion. The reburning fuel flow 9 is configured to be mixed with the reburning air flow 10 to form a reburning mixture, which is output to the reburning region and burns together with the ammonia fuel escaping from the rich region. The burnout dilution air flow 11 is configured to be output to the burnout dilution region and burn with the unburned ammonia fuel entering the burnout dilution region.

[0114] In this embodiment, the space in the combustion chamber is divided into a rich combustion area, a reburning area and a burnout dilution area extending in sequence, the fuel gas premixing channel is configured to output a rich combustion fuel flow 7 and a reburning fuel flow 9, and the air channel is configured to output a rich combustion air flow 8, a reburning air flow 10 and a burnout dilution air flow 11, the rich combustion fuel flow 7 and the rich combustion air flow 8 are mixed and output to the rich combustion area, and the reburning fuel flow 9 and the reburning air flow 10 are mixed and output to the reburning area; so that in most of the NH 3 The equivalence ratio of the rich combustion area where the fuel participates is controlled to be close to the high value of the flammability limit, so that NO x Emissions are greatly reduced, and the reburning mixed flow is relayed downstream, and the equivalence ratio in the reburning region is controlled near a low value close to the flammable limit, thereby effectively controlling the cumulative nitrogen oxide emissions at the outlet and keeping the emissions within an acceptable low range.

[0115] The specific structure of the combustion chamber of this embodiment will be further described as follows:

[0116] In this embodiment, the above-mentioned combustion cavity includes a first combustion chamber section and an outlet contraction section that are arranged axially and connected. The rich combustion region and the reburning region are located in the first combustion chamber section, and the burnout dilution region is located in the outlet contraction section.

[0117] Specifically, the combustion cavity can be a flame tube 5. The flame tube 5 is axially divided into a section with a larger diameter (i.e., corresponding to the above-mentioned first combustion chamber section) and a section with a smaller diameter (i.e., corresponding to the above-mentioned outlet contraction section).

[0118] In this embodiment, axially, the end face of the first combustion chamber section away from the burnout dilution region is the inlet end face. The rich combustion mixture is configured to be output axially through the inlet end face to the rich combustion region. The reburning mixture is configured to be output through the wall surface of the first combustion chamber section to the reburning region, and the output direction is perpendicular to the axial direction. Alternatively, the reburning mixture is configured to be split and output through the wall surface of the first combustion chamber section to the reburning region respectively, and the output direction is perpendicular to the axial direction. The burnout dilution air flow 11 is configured to be output through the outlet contraction section to the burnout dilution region.

[0119] The above-mentioned inlet end face can be a hood 4 installed on the flame tube 5. The above-mentioned rich combustion mixture enters the rich combustion region through the hood 4, and the reburning mixture enters the reburning region through the side wall on the circumference of the flame tube 5.

[0120] In this embodiment, the combustion chamber may further include an outer casing 2 and a rectifying component, and the rectifying component can specifically be a fairing 3.

[0121] The fairing 3 and the above-mentioned flame tube 5 are both arranged in the inner cavity of the outer casing 2. The first end of the fairing 3 is connected to one end of the outer casing 2 close to the rich combustion region, and the second end of the fairing 3 is connected to one end of the flame tube 5 close to the rich combustion region (i.e., the end of the flame tube 5 where the hood 4 is installed). Moreover, the inner cavity wall surface of the outer casing 2 and the rectifying component and the combustion cavity cooperate to form the above-mentioned air passage. The air passage surrounds all of the first combustion chamber section of the flame tube 5 and only part of the outlet contraction section, so that air can be introduced into the burnout dilution region by opening holes on the outlet contraction section, and the air flow of this part can be specifically controlled by setting a flow valve or other means.

[0122] The inner cavity of the fairing 3 can cooperate with the combustion chamber end cover 6 of the outer casing 2 and the hood 4 to form a rich combustion air input cavity communicating with the above-mentioned air passage.

[0123] In this embodiment, the fuel gas premixing passage includes a rich fuel pipeline corresponding to the rich fuel stream 7 and at least one reburning fuel pipeline corresponding to the reburning fuel stream 9. The combustion chamber further includes a rich combustion zone nozzle 1A and at least one reburning zone nozzle 1B (corresponding one-to-one with the reburning fuel pipeline). Among them, both the rich combustion zone nozzle 1A and the reburning zone nozzle 1B can be the above-mentioned multi-fuel mixing nozzle 1.

[0124] The rich combustion zone nozzle 1A can be arranged in the above-mentioned rich combustion air input cavity and connected to the cowl 4. And this rich combustion zone nozzle 1A is configured to receive the rich fuel stream 7 (the above-mentioned rich fuel pipeline passes through the combustion chamber end cover 6 of the outer casing 2 and extends into the rich combustion air input cavity and is connected to the fuel input end of this rich combustion zone nozzle 1A) and the rich combustion air stream 8 (the air input end of this rich combustion zone nozzle 1A can be directly communicated with the rich combustion air input cavity) to perform swirl premixing to form a rich combustion mixture, and the rich combustion mixture is ejected through the opening of the rich combustion zone nozzle 1A on the second side of the cowl 4 to the rich combustion zone, and the output direction is along the axis of the flame tube 5.

[0125] The reburning zone nozzle 1B can be configured to be arranged around the output path of the rich combustion mixture and connected to the combustion chamber (i.e., installed on the circumferential side wall of the flame tube 5 in a surrounding manner). The reburning zone nozzle 1B is configured to receive the reburning fuel stream 9 (the above-mentioned reburning fuel pipeline passes through the outer casing 2 and extends into the air passage and is connected to the fuel input end of this reburning zone nozzle 1B) and the reburning air stream 10 (the air input end of this reburning zone nozzle 1B can be directly communicated with the air passage) to perform swirl premixing to form a reburning mixture, and the reburning mixture is output to the reburning zone, and the output direction can be perpendicular to the axis of the flame tube 5. Among them, the number of the above-mentioned reburning zone nozzles 1B can be 4 to 8, specifically 6, and they are evenly arranged along the circumferential direction.

[0126] Furthermore, at least one mixing hole 5-1 arranged around the output path of the rich combustion mixture can be opened on the outlet contraction section of the flame tube 5. The burnout dilution air stream 11 (i.e., the air flow entering this through hole in the air passage) is output to the burnout dilution area through the mixing hole 5-1, and the output direction can be perpendicular to the axis of the flame tube 5. Among them, the number of the mixing holes 5-1 can be 4 to 8, and they are evenly arranged along the circumferential direction.

[0127] Based on this, the combustion chamber of this embodiment achieves the following beneficial effects:

[0128] 1. Easy to start: The rich combustion zone at the head adopts a swirl burner (multi-fuel mixing nozzle 1), and a recirculation zone is formed downstream, which is beneficial to ignition and flame stabilization. By reasonably setting the fuel quantity under the ignition condition, the equivalence ratio distribution near the head igniter is within the stable combustible range, enabling the gas turbine to achieve normal temperature ignition start, simplifying the ignition start system, and not increasing other types of waste gas emission sources.

[0129] 2. Improve combustion stability: Through the multi-stage arrangement of fuel and air, a rich combustion region, a reburning region, and a burnout dilution region are formed in the combustion chamber. The local equivalence ratio span of each region is large. In particular, the downward exploration space within the stable combustion range of the equivalence ratio in the rich combustion region is large, and the change range of the local partial equivalence ratio during the increase of rotational speed and load can be limited within the combustible range, thereby achieving the effect of stable combustion throughout the process.

[0130] In summary, compared with the prior art, this technical solution forms a rich combustion region, a reburning region, and a burnout dilution region in the combustion chamber through the multi-stage arrangement of fuel and air, reasonably sets the equivalence ratio of each region, can achieve normal temperature ignition start, improves combustion stability and combustion efficiency, and at the same time reduces nitrogen oxide emissions, realizing the stable, efficient, and clean combustion of NH 3 in gas turbines, and facilitating the large-scale application of ammonia in the field of gas turbines.

[0131] Example Five

[0132] Reference Figure 16 , on the basis of the above Example Four, this embodiment adjusts the layout form of the combustion chamber as follows:

[0133] The combustion chamber includes a second combustion chamber section, a third combustion chamber section, and an outlet contraction section arranged and connected axially. The diameter of the second combustion chamber section is smaller than that of the third combustion chamber section, and the diameter of the outlet contraction section is smaller than that of the third combustion chamber section. At least part of the rich combustion region is located in the second combustion chamber section, and the reburning region and the burnout dilution region are located in the third combustion chamber section.

[0134] Axially, the end face of the second combustion chamber section far from the burnout dilution region is the inlet end face, and the end face of the third combustion chamber section far from the burnout dilution region cooperates with the second combustion chamber section to form a stepped end face.

[0135] The rich combustion mixture is configured to be output axially through the inlet end face to the rich combustion region. The reburning mixture is configured to enter the reburning region axially through the stepped end face, or the reburning mixture is configured to be split and enter the reburning region axially through the stepped end face respectively. The burnout dilution air flow 11 is configured to be output to the burnout dilution region through the wall surface of the third combustion chamber section, and the output direction is perpendicular to the axial direction, or the burnout dilution air flow 11 is configured to be split and output to the burnout dilution region through the wall surface of the third combustion chamber section respectively, and the output direction is perpendicular to the axial direction.

[0136] Specifically, the combustion chamber can be a flame tube 5, which includes three sections of cylinders. The diameters of the first section cylinder and the third section cylinder are both smaller than that of the middle second section cylinder. Among them, no transition section is provided between the first section cylinder and the second section cylinder, thus forming the above-mentioned stepped end face, which can be an annular cover cap 4B, while a transition section can be provided between the second section cylinder and the third section cylinder.

[0137] The fairing 3 can be set to be directly connected to the stepped end face of the second section cylinder, so that the space between the stepped end face and the first section cylinder is also located in the above-mentioned rich combustion air input cavity (substantially a cavity shared by rich combustion air and reburning air); the above-mentioned rich combustion area nozzle 1A can still be set on the central cover cap 4A of the first section cylinder, and the rest of the layout is similar to that of the fourth embodiment; the above-mentioned reburning area nozzle 1B can be arranged on the annular cover cap 4B. The above-mentioned reburning fuel pipeline passes through the combustion chamber end cover 6 of the outer casing 2 and extends into the rich combustion air input cavity and is connected to the fuel input end of the reburning area nozzle 1B and the reburning air flow 10 (the air input end of the reburning area nozzle 1B can be directly communicated with the rich combustion air input cavity) to perform swirl premixing to form a reburning mixture gas, and output it to the reburning area, and the output direction can be parallel to the axis of the flame tube 5.

[0138] In this layout mode, part of the burnout dilution area can be moved forward to the second section cylinder, so the above-mentioned mixing holes 5-1 can be arranged at the end position of the second section cylinder.

[0139] In terms of structure in this embodiment, the two levels of the rich combustion area and the reburning area are arranged in a radial stepped manner, realizing relative isolation and independence in physical space and reducing the mutual influence between the two areas.

[0140] Embodiment Six

[0141] On the basis of the above embodiments, this embodiment provides a combustion method, which can be applied to the combustion chamber of the multi-fuel mixing nozzle for a gas turbine having the above-mentioned Embodiment One, and can also be applied to the combustion chambers in the above-mentioned Embodiments Two to Five. The method is as follows:

[0142] A rich combustion area, a reburning area, and a burnout dilution area are arranged in sequence along the axial direction in the combustion chamber. Input the rich combustion mixture gas formed by the rich combustion fuel flow 7 and the rich combustion air flow 8 into the rich combustion area, input the reburning mixture gas formed by the reburning fuel flow 9 and the reburning air flow 10 into the reburning area, and input the burnout dilution air flow 11 into the burnout dilution area;

[0143] Among them, the fuel quantity of the fuel-rich fuel stream 7 accounts for 70% to 100% of the sum of the fuel quantities of the fuel-rich fuel stream 7 and the reburning fuel stream 9; the sum of the air quantities of the fuel-rich air stream 8, the reburning air stream 10, and the burnout dilution air stream 11 is the total air quantity. The air quantity of the fuel-rich air stream 8 accounts for 5% to 25% of the total air quantity, and the air quantity of the reburning air stream 10 accounts for 15% to 30% of the total air quantity.

[0144] The combustion method of this embodiment starts with NH 3 fuel and can burn H 2 , CH 4 and other synthesis gases.

[0145] The technical principle of the combustion chamber of this embodiment will be further described below:

[0146] Refer to Figure 14 , the entire combustion chamber is divided into a fuel-rich region, a reburning region, and a burnout dilution region, and different functional positions are carried.

[0147] The fuel-rich region at the head adopts a multi-fuel mixing nozzle 1 to form a recirculation region downstream, which is beneficial to ignition and flame stabilization. By reasonably setting the fuel quantity under the ignition condition, the equivalence ratio distribution near the head igniter is within the stable combustible range, enabling the gas turbine to achieve normal temperature ignition and start-up, simplifying the ignition and start-up system, and not increasing other types of waste gas emission sources. In addition, in the fuel-rich region, to suppress the emission of nitrogen oxides and maintain stable combustion under variable load conditions, the equivalence ratio of this region is set close to the high value of the combustible limit. For this reason, 5% - 25% of the air quantity and 70% - 100% of the fuel quantity are arranged in the fuel-rich region. As Figure 13 can be seen, in the atmospheric pressure premixed combustion of ammonia, as the equivalence ratio increases, NO x shows a trend of first increasing and then decreasing, and the peak appears near the equivalence ratio of 0.9. In the region where the equivalence ratio is above 1.2, the nitrogen oxide emission tends to 0 ppm, thus achieving the purpose of emission reduction.

[0148] In the case where the air quantity changes little during the load increase and decrease process of the gas turbine, the fuel quantity changes within a large range. For example, within the full speed no-load to full load stage, the overall equivalence ratio of the combustion chamber will increase several times. For this reason, the equivalence ratio of the fuel-rich region under full load is set close to the high value of the combustible limit. In this way, during variable load, especially during load reduction, the downward exploration space within the stable combustion range of the equivalence ratio in the fuel-rich region is large, and the range of the equivalence ratio in the fuel-rich region can be limited within the combustible region, thus achieving the effect of stable combustion throughout the process.

[0149] In the reburning region, it mainly undertakes the task of quickly consuming NH 3 and releasing the fuel heat. The equivalence ratio after the reburning region is set close to the low value of the combustible limit. As Figure 13As shown, in the atmospheric-pressure premixed combustion of ammonia, the residual NH at the outlet 3 increases as the equivalence ratio increases. Predictably, since the equivalence ratio in the fuel-rich region is set to a high value close to the flammable limit, the unburned NH 3 will escape from the fuel-rich region. For this reason, 15 - 30% of the air and 0 - 30% of the NH 3 are arranged in the downstream reburning region, so that the local equivalence ratio before and after the reburning region changes from a high fuel-rich value to a low lean-burn value. However, the overall equivalence ratio in the reburning region is in a stable combustion region, thus quickly consuming the NH 3 fuel.

[0150] Structurally, the two stages of the fuel-rich region and the reburning region are arranged at different axial depths or in a stepped manner along the radial direction to achieve relative isolation and independence in physical space and reduce the mutual influence between the two regions.

[0151] Finally, after entering the burnout dilution region, with the addition of 45 - 80% of the air, the unburned NH 3 is further burned out, improving the combustion efficiency. At the same time, it is quickly diluted to achieve the purpose of cooling and freeze the formation of nitrogen oxides.

[0152] Based on this, the combustion method of this embodiment achieves the following beneficial effects

[0153] 1. Low nitrogen oxide emissions: As Figure 13 shown, in the atmospheric-pressure premixed combustion of ammonia, as the equivalence ratio rises, the NO x shows a trend of first increasing and then decreasing, with the peak appearing near the equivalence ratio of 0.9. In the range above the equivalence ratio of 1.2, the nitrogen oxide emissions tend to be 0. Through the multi-stage arrangement of air and fuel, the air volume ratio in the fuel-rich region is 5 - 25% and the fuel volume ratio is 70% - 100%, so that the equivalence ratio in the fuel-rich region where most of the NH 3 fuel participates is controlled at a high value close to the flammable limit, greatly reducing the NO x emissions. Downstream, with the subsequent addition of 15 - 30% of the air and 0 - 30% of the fuel, the equivalence ratio in the reburning zone is controlled near the low value close to the flammable limit, also deviating from the peak equivalence ratio of nitrogen oxides, 0.9. Thus, the cumulative nitrogen oxide emissions at the outlet are effectively controlled, making the emissions within an acceptable low range.

[0154] 2. Improve combustion efficiency: To reduce NO x , the equivalence ratio in the fuel-rich region is controlled at a high value close to the flammable limit, while the residual NH at the outlet 3 increases as the equivalence ratio increases, as shown in the appendix Figure 1 . Predictably, the unburned NH 3It will escape from the fuel-rich region. Therefore, 15-30% of the air and 0-30% of NH 3 are arranged in the reburning zone, so that the change range of the local equivalence ratio before and after the reburning zone spans from the high fuel-rich value to the low lean-burn value. However, the overall equivalence ratio in the reburning zone is in a stable combustion interval, thus rapidly consuming NH 3 fuel. After entering the burnout dilution zone, with the addition of 45-80% of the air, the unburned NH 3 is further burned out, improving the combustion efficiency. At the same time, it is rapidly diluted to achieve the purpose of cooling and freeze the formation of nitrogen oxides.

[0155] The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, provided that these changes fall within the scope of the claims of the present invention and their equivalent technologies, they still fall within the protection scope of the present invention.

Claims

1. A multi-fuel mixing nozzle for a gas turbine, characterized in that: It comprises a fuel nozzle body, in which a fuel gas premixing channel, a swirl premixing gas output channel, a fuel gas diffusion channel and a radial fast mixing air channel are arranged; Along the gas flow direction in the swirl premixed gas output channel, the output ends of the fuel gas premixed channel, the fuel gas diffusion channel and the radial fast mixing air channel are sequentially connected to the swirl premixed gas output channel; Wherein, the fuel gas premixing channel is configured to output premixed fuel gas having low reactivity characteristics to the upstream of the swirl premixed gas output channel in a premixed manner; The fuel gas diffusion channel is configured to output the fuel gas with high reactivity characteristics or the fuel gas with low reactivity characteristics to the downstream of the swirl premixed gas output channel in a diffusion manner; The output end of the radial fast-mixing air channel is located downstream of the output end of the fuel gas diffusion channel, and the radial fast-mixing air channel is configured to output radial fast-mixing air to the swirl premixed gas output channel; The fuel gas premixing channel includes a premixing fuel gas channel and a premixing air channel; the interval between adjacent swirl blades on the fuel nozzle body forms the premixing air channel, and the premixing fuel gas channel is configured to extend inside the swirl blade and spray from the surface of the swirl blade to output low-reactivity characteristic fuel gas toward the premixing air channel; the swirl blade is configured to guide the premixed air entering the premixing air channel to be premixed with the low-reactivity characteristic fuel gas to form the premixed fuel gas, and output it to the swirl premixed gas output channel to be converted into a radial swirl form or an axial swirl form; The output end of the fuel gas diffusion channel is connected to the downstream of the swirl premixed gas output channel through a plurality of discretely arranged fuel gas diffusion injection holes; the output end of the radial fast mixing air channel is connected to the swirl premixed gas output channel through a plurality of discretely arranged radial fast mixing air channel injection ports, and the radial fast mixing air channel injection ports are located downstream of the fuel gas diffusion injection holes and are staggered in the circumferential direction along the swirl direction.

2. The multi-fuel mixing nozzle for a gas turbine according to claim 1, characterized in that: At least a portion of the swirl premixed gas output channel is configured to have a diameter that gradually decreases along the gas flow direction to accelerate the gas flow rate therein.

3. The multi-fuel mixing nozzle for a gas turbine according to claim 1, characterized in that: The swirl blades are radial swirl blades or axial swirl blades.

4. The multi-fuel mixing nozzle for a gas turbine according to claim 1, characterized in that: The low-reactivity fuel gas is ammonia or methane or a synthesis gas with a low hydrogen content.

5. The multi-fuel mixing nozzle for a gas turbine according to claim 1, characterized in that: The high-reactivity fuel gas is hydrogen or a synthesis gas with a high hydrogen content.

6. A multi-fuel combustion chamber based on the combustion of ammonia-based low-reactivity fuel, characterized in that: A multi-fuel mixing nozzle for a gas turbine comprising a combustion chamber and the multi-fuel mixing nozzle for a gas turbine according to any one of claims 1 to 5 installed in the combustion chamber; The combustion chamber is provided with a combustion zone extending in the axial direction, and the combustion zone includes a rich combustion zone, a reburning zone and a burnout dilution zone arranged in sequence in the axial direction; The multi-fuel mixing nozzle is configured to output a rich fuel mixed fuel gas of a rich fuel flow and a rich fuel air flow toward the rich combustion area and / or output a reburning mixed fuel gas of a reburning fuel flow and a reburning air flow toward the reburning area; The fuel-rich air flow accounts for 5% to 25% of the total air volume, the reburning air flow accounts for 15% to 30% of the total air volume, and the burnt dilution air flow entering the burnt dilution zone accounts for 45% to 80% of the total air volume.

7. The multi-fuel combustion chamber based on combustion of ammonia low-reactivity fuel as claimed in claim 6, characterized in that: The rich fuel flow and the reburning fuel flow are ammonia-based low-reactivity fuel gas, the rich fuel flow accounts for 70% to 100% of the total amount of the ammonia-based low-reactivity fuel gas, corresponding to a rich state with a head equivalence ratio between 1 and 2, and the reburning fuel flow accounts for 0% to 30% of the total amount of the ammonia-based low-reactivity fuel gas; The ammonia low-reactivity fuel gas is configured to enter the swirl premixed gas output channel via the fuel gas premixing channel and / or the fuel gas diffusion channel.

8. The multi-fuel combustion chamber based on combustion of ammonia-based low-reactivity fuel as claimed in claim 6, characterized in that: The rich fuel flow and the reburn fuel flow are hydrogen-based high-activity fuel gas, the rich fuel flow accounts for 5% to 25% of the total amount of the hydrogen-based high-activity fuel gas, and the reburn fuel flow accounts for 95% to 75% of the total amount of the hydrogen-based high-activity fuel gas; The hydrogen-based high-activity fuel gas is configured to enter the swirl premixed gas output channel via the fuel gas diffusion channel.

9. The multi-fuel combustion chamber based on combustion of ammonia-based low-reactivity fuel according to claim 6 or 7, characterized in that: After determining the distribution ratio of air and ammonia low-reactivity fuel gas in the rich combustion area, reburning area and burnout dilution area of ​​the combustion chamber based on ammonia low-reactivity fuel, hydrogen high-reactivity fuel gas or other low-reactivity fuel gas is introduced from the nozzle fuel gas diffusion channel to achieve multi-fuel co-firing.

10. A combustion chamber, characterized in that: comprising at least one multi-fuel mixing nozzle for a gas turbine according to any one of claims 1 to 5; Also includes: A combustion chamber, wherein a combustion zone extending along the axial direction is provided in the combustion chamber, and the combustion zone includes a rich combustion zone, a reburning zone and a burnout dilution zone arranged in sequence along the axial direction; a fuel gas passage configured to output a rich fuel flow and a reburn fuel flow; an air passage configured to split the total air flow therein and output a fuel-rich air flow, a reburning air flow, and a burnout dilution air flow; wherein the rich fuel flow is configured to be mixed with the rich air flow in the multi-fuel mixing nozzle to form a rich mixture, and the rich mixture is output to the rich region and ignited to perform rich combustion; the reburning fuel flow is configured to be mixed with the reburning air flow in the multi-fuel mixing nozzle to form a reburning mixture, and the reburning mixture is output to the reburning region to be co-burned with the low-reactivity fuel gas escaping from the rich region; the burnout dilution air flow is configured to be output to the burnout dilution region to burn with unburned low-reactivity fuel gas entering the burnout dilution region.

11. The combustion chamber according to claim 10, characterized in that The multi-fuel mixing nozzles in the rich combustion zone and the reburning zone are arranged at different depths along the axial direction of the combustion chamber.

12. The combustion chamber according to claim 10, characterized in that The multi-fuel mixing nozzles in the fuel-rich zone and the reburning zone are arranged in a stepped manner along the radial direction of the combustion chamber.

13. A combustion method, characterized in that: Applied to a combustion chamber comprising a multi-fuel mixing nozzle for a gas turbine as claimed in any one of claims 1 to 5, or applied to a combustion chamber as claimed in any one of claims 6 to 12, the method is as follows: The combustion chamber is provided with a rich combustion area, a reburning area and a burnout dilution area arranged in sequence along the axial direction; Inputting a rich fuel mixture formed by a rich fuel flow and a rich fuel air flow into the rich fuel region, inputting a reburning mixture formed by a reburning fuel flow and a reburning air flow into the reburning region, and inputting a burnout dilution air flow into the burnout dilution region; wherein the fuel amount of the rich fuel flow accounts for 70% to 100% of the sum of the fuel amounts of the rich fuel flow and the reburn fuel flow; The sum of the air amounts of the fuel-rich air flow, the recombustion air flow and the burnt-out dilution air flow is the total air amount, the air amount of the fuel-rich air flow accounts for 5% to 25% of the total air amount, and the air amount of the recombustion air flow accounts for 15% to 30% of the total air amount.

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