Multi-fuel mixing nozzle for gas turbine, and combustion chamber and combustion method

Abstract

The present invention is applied to the technical field of gas turbines. Disclosed are a multi-fuel mixing nozzle for a gas turbine, and a combustion chamber and a combustion method. Output ends of a fuel gas premixing passage, a fuel gas diffusion passage and a radial rapid-mixing air passage are configured to sequentially communicate with a swirl premixed gas output passage in a fuel nozzle body. When a low-reactivity fuel gas is combusted, a premixed fuel gas containing the low-reactivity fuel gas is mixed with radial rapid-mixing air in the swirl premixed gas output passage and is outputted, or is sequentially mixed with a high / low-reactivity fuel gas ejected from the fuel gas diffusion passage and the radial rapid-mixing air and is outputted, thereby achieving stable combustion. When only the high-reactivity fuel gas is combusted, the high-reactivity fuel gas is outputted into the swirl premixed gas output passage through the fuel gas diffusion passage, and undergoes multiple cross-jets with upstream swirl air and the downstream radial rapid-mixing air, thereby achieving rapid mixing and low-nitrogen combustion.

Description

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

[0001] This invention belongs to the field of gas turbine technology, and particularly relates to a multi-fuel mixing nozzle, combustion chamber and combustion method for a gas turbine. Background Technology

[0002] Over the past few decades, the extensive use of hydrocarbon fuels has generated emissions of pollutants, including greenhouse gases CO2 and NOx, leading to global warming and various forms of environmental pollution. This has caused significant and irreversible damage to ecosystems and posed risks to human health and survival. Therefore, replacing traditional fuels to achieve zero carbon emissions is crucial. With the accelerated progress of emission reduction and decarbonization in the energy and power industry, the demand for clean alternative fuels in gas turbines is becoming increasingly prominent. This means that gas turbine combustion technology must also be upgraded accordingly, requiring upgrades to the corresponding combustion nozzles and combustion chambers.

[0003] Hydrogen is one of the most popular carbon-free fuels and has been widely used in fuel cells as a highly reactive fuel gas. As shown in Figure 1, replacing traditional fuels with hydrogen significantly reduces CO2 emission intensity. However, hydrogen cannot be found in nature and must be produced, and its high reactivity results in flammability and explosiveness. Another consideration is the high cost of liquefying and transporting liquid hydrogen. These combined factors of economics and safety hinder the widespread use of hydrogen at present.

[0004] Also a carbon-free fuel, NH3 is another effective hydrogen carrier with a higher hydrogen density per unit volume than liquid hydrogen. Furthermore, large-scale production is well-established due to over 100 years of commercial demand; its easy liquefaction significantly reduces storage, transportation, and related development costs. However, low combustion rates and high NOx emissions from fuel-type NH3 inhibit its large-scale use in several ways:

[0005] (1) Low flame propagation speed: The flame speed of NH3 under atmospheric pressure and ambient temperature is relatively low, only 7 cm / s, which easily leads to low combustion efficiency and incomplete combustion.

[0006] (2) High minimum ignition energy: The minimum ignition energy of NH3 is 8mJ, which is about 40 times that of H2, and ignition requires higher spark energy.

[0007] (3) High ignition temperature: The ignition temperature of NH3 is higher than that of other common fuels;

[0008] (4) Narrow flammability limit: Compared with H2, NH3 has a much narrower flammability limit, which may lead to misfire under lean or rich fuel conditions;

[0009] (5) Difficulty in starting: Given the poor reactivity of ammonia fuel, it is often necessary to use a starting fuel when igniting. For example, some Japanese manufacturers use carbon-containing fuels such as kerosene, diesel, and methane for starting, which not only increases investment but also causes carbon emission problems. If hydrogen is used for starting, it will also increase the complexity of the system.

[0010] (6) Potentially high NOx emissions: Ammonia fuel contains nitrogen, so in addition to thermal NOx, it will also produce more fuel NOx, and an unreasonable equivalence ratio distribution in the combustion chamber will exacerbate this high emission trend.

[0011] With advancements in combustion technology, the roadmap for the use of alternative clean and carbon-free fuels has become largely clear. At present, the priority is to develop and use NH3 fuel, while focusing on overcoming the challenges of low fuel activity and high NOx emissions. Once the challenges of large-scale production, storage, and transportation of hydrogen are resolved, the ultimate energy source will be hydrogen.

[0012] At the same time, it's crucial to recognize the differences in energy distribution, extraction, and usage across countries. Many uncertainties remain regarding available alternative clean fuels for gas-fired power generation, and it's highly unlikely that only a single fuel will be available in various global application scenarios. This means that fuel flexibility will be a critical design element for new gas turbines, particularly evident in industries such as petroleum, refining, textiles, printing and dyeing, and metallurgy. These sectors have significant demands for electricity and steam, while simultaneously offering a wide variety of fuels. However, typical combustion chambers only support the combustion of specific fuels; changing fuels results in substantial differences in the Wobbe index, making it impossible to guarantee the same heat load under the same combustion pressure. Furthermore, alterations in fuel activity will lead to changes in the temperature field, impacting combustion stability and other aspects. 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 gas turbines, so as to solve the problem that 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] The present invention provides a multi-fuel mixing nozzle for a gas turbine, comprising a fuel nozzle body, wherein the fuel nozzle body is provided with a fuel gas premixing channel, a swirling premixed gas output channel, a fuel gas diffusion channel, and a radial fast mixing air channel;

[0016] Along the gas flow direction within the swirling premixed gas output channel, the output ends of the fuel gas premixing channel, the fuel gas diffusion channel, and the radial fast mixed air channel are sequentially connected to the swirling premixed gas output channel.

[0017] The fuel gas premixing channel is configured to output premixed fuel gas with low reactivity in a premixed manner to the upstream of the swirl premixed gas output channel.

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

[0019] 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.

[0020] The multi-fuel mixing nozzle for gas turbines of the present invention has at least a portion of the swirling premixed gas output channel configured with a diameter that gradually decreases along the airflow direction to accelerate the gas flow velocity therein.

[0021] The present invention provides a multi-fuel mixing nozzle for a gas turbine, wherein the swirling premixed gas output channel includes a fuel gas premixing channel and a premixed air channel;

[0022] The premixed air channel is formed by the spacing between adjacent swirl blades on the fuel nozzle body. The fuel gas premixed channel is configured to extend within the swirl blades and be injected from the surface of the swirl blades, outputting low-reactivity fuel gas toward the premixed air channel. The swirl blades are configured to guide the premixed air entering the premixed air channel to premix with the low-reactivity 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 or axial swirl.

[0023] The multi-fuel mixing nozzle for gas turbines of the present invention may employ radial swirling blades or axial swirling blades.

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

[0025] The present invention relates to a multi-fuel mixing nozzle for gas turbines, wherein the low-reactivity fuel gas is ammonia, methane, or syngas with low hydrogen content.

[0026] The present invention relates to a multi-fuel mixing nozzle for gas turbines, wherein the highly reactive fuel gas is hydrogen or syngas with a high hydrogen content.

[0027] The present invention provides a multi-fuel combustion chamber based on the combustion of ammonia-based low-activity fuels, comprising a combustion chamber and a multi-fuel mixing nozzle for a gas turbine as described in any one of the above-mentioned embodiments, installed in the combustion chamber;

[0028] The combustion chamber is provided with an axially extending combustion zone, which includes a fuel-rich zone, a reburning zone, and a burnout dilution zone arranged sequentially along the axial direction.

[0029] The multi-fuel mixing nozzle is configured to output a fuel-rich mixture of fuel-rich fuel flow and fuel-rich air flow toward the fuel-rich region and / or to output a reburning mixture of reburning fuel flow and reburning air flow toward the reburning region.

[0030] The fuel-rich airflow accounts for 5% to 25% of the total air volume, the reburning airflow accounts for 15% to 30% of the total air volume, and the burnout dilution airflow entering the burnout dilution zone accounts for 45% to 80% of the total air volume.

[0031] The present invention relates to a multi-fuel combustion chamber based on the combustion of ammonia-based low-activity fuels, wherein the fuel-rich stream and the reburning fuel stream are ammonia-based low-activity fuel gases, the fuel-rich stream accounts for 70% to 100% of the total amount of ammonia-based low-activity fuel gases, corresponding to a fuel-rich state with a head equivalence ratio between 1 and 2, and the reburning fuel stream accounts for 0% to 30% of the total amount of ammonia-based low-activity fuel gases.

[0032] The ammonia-based low-activity 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.

[0033] The present invention relates to a multi-fuel combustion chamber based on the combustion of ammonia-based low-activity fuels, wherein the fuel-rich stream and the reburning fuel stream are hydrogen-based high-activity fuel gases, the fuel-rich stream accounts for 5% to 25% of the total amount of hydrogen-based high-activity fuel gases, and the reburning fuel stream accounts for 95% to 75% of the total amount of hydrogen-based high-activity 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] The multi-fuel combustion chamber based on ammonia fuel combustion of the present invention, after determining the distribution ratio of air and ammonia-based low-reactivity fuel gas in the combustion chamber's fuel-rich zone, reburning zone, and burnout dilution zone based on ammonia-based low-reactivity fuel, introduces hydrogen-based high-reactivity fuel gas or other low-reactivity fuel gas through the fuel gas diffusion channel of the nozzle to achieve multi-fuel co-combustion.

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

[0037] Also includes:

[0038] The combustion chamber has an axially extending combustion zone, which includes a fuel-rich zone, a reburning zone, and a burnout dilution zone arranged sequentially along the axial direction.

[0039] A fuel gas passage configured to output a fuel-rich fuel flow and a reburning fuel flow;

[0040] An air passage configured to split the total airflow within it and output a fuel-rich airflow, a reburning airflow, and a burnout dilution airflow;

[0041] The fuel-rich flow is configured to mix with the fuel-rich air flow in the multi-fuel mixing nozzle to form a fuel-rich mixture, which is then output to the fuel-rich region and ignited for fuel-rich combustion. The reburning fuel flow is configured to mix with the reburning air flow in the multi-fuel mixing nozzle to form a reburning mixture, which is then output to the reburning region for co-combustion with the low-reactivity fuel gas escaping from the fuel-rich region. The burnout dilution air flow is configured to be output to the burnout dilution region for combustion with the unburned low-reactivity fuel gas entering the burnout dilution region.

[0042] In the combustion chamber of the present invention, the multi-fuel mixing nozzles of the fuel-rich zone and the reburning zone are arranged at different depths along the axial direction of the combustion chamber.

[0043] In the combustion chamber of the present invention, the multi-fuel mixing nozzles of the fuel-rich zone and the reburning zone 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 comprising a multi-fuel mixing nozzle for a gas turbine as described in any one of the above claims, or applied to a combustion chamber as described in any one of the above claims, the method being as follows:

[0045] The combustion chamber is provided with a fuel-rich zone, a reburning zone, and a burnout dilution zone arranged sequentially along the axial direction;

[0046] A fuel-rich mixture formed by a fuel-rich flow and a fuel-rich air flow is input into the fuel-rich region; a reburning mixture formed by a reburning fuel flow and a reburning air flow is input into the reburning region; and a burnout dilution air flow is input into the burnout dilution region.

[0047] The fuel quantity of the rich fuel stream accounts for 70% to 100% of the sum of the fuel quantities of the rich fuel stream and the reburning fuel stream.

[0048] The sum of the air volume of the fuel-rich air stream, the reburning air stream, and the burnout dilution air stream constitutes the total air volume. The air volume of the fuel-rich air stream accounts for 5% to 25% of the total air volume, and the air volume of the reburning air stream accounts for 15% to 30% of the total air volume.

[0049] Because the present invention adopts the above technical solution, it has the following advantages and positive effects compared with the prior art:

[0050] I. One embodiment of the present invention provides a fuel gas premixing channel, a swirling premixed gas output channel, a fuel gas diffusion channel, and a radial fast-mixing air channel within 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 low-reactivity fuel gas, the premixed fuel gas containing low-reactivity fuel gas mixes with the radial fast-mixing air in the swirling premixed gas output channel and is output, or it mixes with high / low-reactivity fuel gas ejected from the fuel gas diffusion channel and the radial fast-mixing air sequentially and is output, thereby achieving stable combustion. When only high-reactivity fuel gas is burned, the high-reactivity fuel gas is output through the fuel gas diffusion channel to the swirling premixed gas output channel, where it cross-jet multiple times with the upstream swirling air and the downstream radial fast-mixing air to achieve rapid mixing and low-NOx combustion. This allows the multi-fuel mixing nozzle to burn low-reactivity fuel gas such as NH3 alone, high-reactivity fuel gas such as H2 alone, or both low-reactivity and high-reactivity fuel gas simultaneously, improving fuel flexibility.

[0051] II. One embodiment of the present invention divides the combustion chamber into a sequentially extending fuel-rich region, a reburning region, and a burnout dilution region. The fuel gas premixing channel is configured to output a fuel-rich fuel stream and a reburning fuel stream, and the air channel is configured to output a fuel-rich air stream, a reburning air stream, and a burnout dilution air stream. The fuel-rich fuel stream and the fuel-rich air stream are mixed and output to the fuel-rich region, and the reburning fuel stream and the reburning air stream are mixed and output to the reburning region. The proportions of each fuel stream and each air stream are adjusted so that the equivalence ratio in the fuel-rich region, where most of the NH3 fuel is involved, is controlled at a value close to the high value of the combustible limit, which greatly reduces NOx emissions. The downstream reburning mixed stream is added in turn, and the equivalence ratio in the reburning region is controlled at a value close to the low value of the combustible limit. This effectively controls the cumulative nitrogen oxide emissions at the outlet, keeping the emissions within an acceptable low range, while ensuring stable combustion and burnout. Attached Figure Description

[0052] Figure 1 is a schematic diagram illustrating the effect of H2 content in CH4 fuel on CO2 emission intensity;

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

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

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

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

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

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

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

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

[0061] Figure 10 is a cross-sectional view of the combustion chamber of Embodiment 2 of the present invention;

[0062] Figure 11 is another cross-sectional view of the combustion chamber of Embodiment 2 of the present invention;

[0063] Figure 12 is a schematic diagram of the structure of the combustion chamber cap according to Embodiment 2 of the present invention;

[0064] Figure 13 is a schematic diagram showing the effect of the change in equivalence ratio on the composition of the outlet flue gas during atmospheric pressure premixed combustion of NH3.

[0065] Figure 14 is a schematic diagram of the multi-stage combustion technology of the combustion chamber in Embodiments 3 and 4 of the present invention;

[0066] Figure 15 is a cross-sectional view of the combustion chamber in Embodiments 3 and 4 of the present invention;

[0067] Figure 16 is a cross-sectional view of the combustion chamber of Embodiment 5 of the present invention;

[0068] Figure 17 is a schematic diagram of the combustion chamber of Embodiment 3 of the present invention.

[0069] Explanation of reference numerals in the attached drawings: 1. Multi-fuel mixing nozzle; 1A. Fuel-rich zone 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 delivery pipe; 1-4. Fuel gas diffusion channel radial return pipe; 1-5. Annular fuel gas output channel; 1-6. Fuel gas diffusion injection orifice; 1-7. Fuel gas premixing channel inlet pipe; 1-8. Fuel gas premixing channel axial interlayer channel; 1-9. Fuel gas premixing channel radial diffusion pipe; 1-10. Fuel gas premixing channel 1. Axial delivery pipe; 1-11. Fuel gas premixing channel injection port; 1-12. Rapid mixed air radial delivery pipe; 1-13. Rapid mixed air axial delivery pipe; 1-14. Radial rapid mixed air channel injection port; 1-15. Swirl blades; 1-16. Tangential air channel; 1-17. Swirl premixed gas output channel; 2. Outer casing; 3. Fairing; 4. Cap; 5. Flame tube; 5-1. Mixing hole; 6. Combustion chamber end cover; 7. Rich fuel flow; 8. Rich air flow; 9. Reburning fuel flow; 10. Reburning air flow; 11. Burnout dilution air flow. Detailed Implementation

[0070] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a multi-fuel mixing nozzle, combustion chamber, and combustion method for a gas turbine according to the present invention. The advantages and features of the present invention will become clearer from the following description.

[0071] Example 1

[0072] Referring to Figures 2 to 9, in one embodiment, the multi-fuel mixing nozzle 1 for a gas turbine includes a fuel nozzle body, within which are provided a swirling premixed gas output channel 1-17, a fuel gas premixing channel, a fuel gas diffusion channel, and a radial fast-mixing air channel. Along the gas flow direction (from upstream to downstream) within the swirling premixed gas output channel, 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 1-17.

[0073] The fuel gas premixing channel is configured to output premixed fuel gas with low reactivity characteristics (such as NH3, low H2 content synthesis gas, CH4) to the upstream of the swirl premixed gas output channel 1-17. The fuel gas diffusion channel is configured to output fuel gas with low reactivity characteristics (such as NH3, low H2 content synthesis gas, CH4) or high reactivity characteristics (such as H2, high hydrogen content synthesis gas) to the downstream of the swirl premixed gas output channel 1-17. The output end of the radial fast-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 fast-mixing air channel is configured to output radial fast-mixed air to the swirl premixed gas output channel 1-17.

[0074] In this embodiment, a swirling premixed gas output channel 1-17, a fuel gas premixing channel, a fuel gas diffusion channel, and a radial fast-mixing air channel are provided 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. The fuel gas premixing channel outputs premixed fuel gas containing fuel gas with low reactivity characteristics to the upstream of the swirling premixed gas output channel 1-17. The fuel gas diffusion channel outputs fuel gas with low reactivity characteristics or fuel gas with high reactivity characteristics to the downstream of the swirling premixed gas output channel 1-17. The radial fast-mixing air channel outputs radial fast-mixed air to the swirling premixed gas output channel 1-17 and is located downstream of the output end of the fuel gas diffusion channel, and is slightly offset in the circumferential direction along the swirling direction, so as to achieve cross-jet of diffused fuel.

[0075] When burning low-reactivity fuel gases, the premixed fuel gas containing low-reactivity fuel gases is mixed with radial fast-mixed air in the swirling premixed gas output channel and then output, or it is mixed with high / low-reactivity fuel gases and radial fast-mixed air ejected from the fuel gas diffusion channel and then output, to achieve stable combustion. When burning only high-reactivity fuel gases, the high-reactivity fuel gases are output to the swirling premixed gas output channel through the fuel gas diffusion channel, and are repeatedly cross-jeted with upstream swirling air and downstream radial fast-mixed air to achieve rapid mixing and low-NOx combustion. This allows the multi-fuel mixing nozzle to burn low-reactivity fuel gases such as NH3 alone, high-reactivity fuel gases such as H2 alone, or both low-reactivity and high-reactivity fuel gases simultaneously, greatly expanding the types of fuels that can be used and improving fuel flexibility.

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

[0077] In this embodiment, at least a portion of the aforementioned swirling premixed gas output channel is configured with a diameter that gradually decreases along the airflow direction, so that the gas flow rate of the premixed fuel gas and / or high-reactivity fuel gas entering it is gradually increased to accelerate mixing. Specifically, the swirling premixed gas output channel may include an annular mixing section and an annular tapering section connected sequentially along the flow direction. At least a portion of the annular tapering section is configured with a diameter that gradually decreases along the airflow direction. The premixed fuel gas may be configured to be input into the annular mixing section, and the fuel gas from the fuel gas diffusion channel may be configured to be input into the annular mixing section and / or the annular tapering section, thereby allowing the premixed fuel gas and the diffused fuel gas to gradually accelerate within the annular tapering section, resulting in more uniform mixing.

[0078] Furthermore, the aforementioned premixed fuel gas can be specifically configured to be injected tangentially into the swirling premixed gas output channel (annular mixing section) and output downstream in an axial spiral form within the annular mixing section. That is, the annular mixing section receives the swirling mixed gas and converts it into premixed fuel gas that moves axially in a spiral motion and is output towards the annular tapering section.

[0079] Referring to Figures 8 and 9, in this embodiment, the swirl premixed gas output channel may specifically include a premixed air channel and a fuel gas premixed channel. The premixed air channel is formed by the interval between adjacent swirl blades 1-15 on the fuel nozzle body. The fuel gas premixed channel is configured to extend within the swirl blades and be injected from the surface of the swirl blades 1-15, outputting low-reactivity fuel gas toward the premixed air channel. The swirl blades 1-15 are configured to guide the premixed air entering the premixed air channel to premix with the low-reactivity fuel gas to form premixed fuel gas, which is then output into the swirl premixed gas output channel and converted into a radial swirl or axial swirl form.

[0080] Specifically, the premixed air passage can be a number of tangential air passages 1-16 spaced circumferentially on the fuel nozzle body (circumferentially spaced by swirl vanes). The tangential air passages 1-16 are axially discretely and uniformly distributed on the fuel nozzle body. The airflow direction of the tangential air passages 1-16 is tangential to the annular mixing section. The tangential air passages 1-16 guide the outer layer air tangentially into the nozzle and disturb the flow field, forming swirling air. The nozzle body portion between adjacent tangential air passages 1-16 is the asymmetric fan-shaped swirl vane 1-15. The swirl vane 1-15 can be radial swirl vanes or axial swirl vanes.

[0081] Furthermore, the fuel gas premixing channel includes a fuel gas premixing channel input section and several fuel gas premixing channel output sections connected in sequence.

[0082] The output sections of the fuel gas premixing channels can specifically be axial delivery pipes 1-10, each corresponding to a tangential air channel 1-16. Each axial delivery pipe 1-10 is connected to the tangential air channel 1-16 via several axially spaced fuel gas premixing channel injection holes 1-11. Specifically, the fuel gas premixing channel output sections are located within the swirl vanes 1-15, and the fuel gas premixing channel injection holes 1-11 are also located within the swirl vanes 1-15. The axial delivery pipes 1-10 can be connected to two corresponding tangential air channels 1-16 on either side via the fuel gas premixing channel injection holes 1-11. The fuel gas premixing channel injection holes 1-11 can be arranged discretely and evenly along the height direction of the swirl vanes 1-15, thus directing fuel gas towards the two tangential air channels 1-16 on either side.

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

[0084] In this embodiment, the fuel gas diffusion channel may specifically include a fuel gas diffusion channel input section, several fuel gas diffusion channel bend sections, and a fuel gas diffusion channel output section. The several fuel gas diffusion channel bend sections are spaced apart circumferentially, and the two ends of each bend section are connected to the fuel gas diffusion channel input section and the fuel gas diffusion channel output section, respectively. The fuel gas diffusion channel output section is located inside the annular mixing section and the annular tapering section, and its end is connected to the annular tapering section through several circumferentially spaced fuel gas diffusion injection holes 1-6, i.e., fuel gas is ejected radially outward.

[0085] Specifically, the fuel gas diffusion channel input section is the fuel gas diffusion channel inlet pipe 1-1, the fuel gas diffusion channel bending section consists of the 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 connected in sequence, and the fuel gas diffusion channel output section is the annular output channel 1-5. Fuel gas enters from the fuel gas diffusion channel inlet pipe 1-1, and then enters each of the fuel gas diffusion channel radial diffusion pipes 1-2 and is transported radially outward to the fuel gas diffusion channel axial delivery pipe 1-3, where it is converted to axial delivery. Then it enters the fuel gas diffusion channel radial return pipe 1-4 and is transported radially inward. The fuel gas in each of the fuel gas diffusion channel radial return pipes 1-4 converges in the annular output channel 1-5 and is ejected radially outward through the fuel gas diffusion injection hole 1-6 on it. The design of the reciprocating channel of the fuel gas diffusion channel bending section is for structural layout purposes. On the other hand, while achieving the purpose of supplying inner diffusion fuel, the bending and conveying reduces the pressure gradient between the areas near fuel gas diffusion injection holes 1-6, thereby improving the uniformity of the injected fuel.

[0086] In this embodiment, the radial fast-mixing air passage includes several inner fast-mixing air input sections and inner fast-mixing air output sections. The inner fast-mixing air output sections are located inside the output section of the fuel gas diffusion passage. The several inner fast-mixing air input sections pass through the fuel nozzle body and connect to the inner fast-mixing air output sections, and the several inner fast-mixing air input sections are arranged alternately with the bends in the fuel gas diffusion passage.

[0087] Specifically, the inner fast-mixed air input section can be a fast-mixed air radial delivery pipe 1-12, and the inner fast-mixed air output section can be a fast-mixed air axial delivery pipe 1-13. The end of the fast-mixed air axial delivery pipe 1-13 is circumferentially spaced with several radial fast-mixed air channel injection ports 1-14, which are located axially downstream of the annular tapering section. The fast-mixed air radial delivery pipe 1-12 is arranged in the area corresponding to the bend section of the aforementioned fuel gas diffusion channel and is offset from it. External air enters the fast-mixed air axial delivery pipe 1-13 radially from the fast-mixed air radial delivery pipe 1-12 and converges, then moves within the fast-mixed air axial delivery pipe 1-13 and is delivered to the radial fast-mixed air channel injection ports 1-14 at the end, from which it is radially output outwards. The radial fast-mixing air injection port 1-14 is located downstream of the fuel gas diffusion injection port 1-6, and can be arranged in a staggered manner along the swirling direction in the circumferential direction. That is, the injection direction of the radial fast-mixing air injection port 1-14 is not tangent to the rotation direction of the spirally advancing fuel at the annular tapering section, so as to achieve cross-jet flow and make the mixing more uniform.

[0088] In this embodiment, for low-reactivity fuel gas, represented by NH3 fuel, the low-reactivity fuel gas enters from the fuel gas premixing channel, or simultaneously from the fuel gas diffusion channel and the fuel gas premixing channel. The low-reactivity fuel gas and air in the fuel gas premixing channel complete the first "cross-jet" in the tangential air channel 1-16, mixing and being tangentially injected into the annular mixing section. While completing the flow field swirl, the direction of motion changes from tangential to axial spiral rotation. Near the nozzle outlet, as the channel narrows, the mixed gas accelerates, turbulent kinetic energy increases, and the mixing becomes more uniform. Further downstream of the nozzle, a standby diffusion combustion (i.e., fuel gas output through the fuel gas diffusion injection hole 1-6, where the fuel gas can be low-reactivity or high-reactivity fuel gas) is organized, playing a crucial supporting role in ignition start-up and stable combustion. However, from the perspective of reducing NOx emissions, the existence of local high stoichiometric regions is also undesirable. Therefore, a radial fast-mixing air channel injection port 1-14 is arranged downstream of the fuel gas diffusion injection hole 1-6. In this way, the low-reactivity fuel gas or high-reactivity fuel gas ejected from the fuel gas diffusion injection holes 1-6 completes the second "cross-jet" with the mixed gas in the annular converging section. After completing the exchange of momentum and rapid mixing, it then collides perpendicularly with the radial fast-mixed air output from the radial fast-mixed air channel injection holes 1-14, completing the third "cross-jet". With this arrangement, after three "cross-jet" processes, the swirling flow field is established while the mixing process is completed rapidly.

[0089] For highly reactive fuel gases, such as H2 fuel, to prevent nozzle backfire, the fuel can be configured to enter only through the fuel gas diffusion channel.

[0090] Similarly, the fuel gas ejected from the fuel gas diffusion injection holes 1-6 completes the first "cross jet" with the air in the annular tapering section. After rapidly mixing and exchanging momentum, it then collides perpendicularly with the radial fast-mixing air channel injection holes 1-14, completing the second "cross jet". With this arrangement, the swirling flow field is established and the mixing process is completed rapidly after two "cross jets".

[0091] Preferably, CH4 is used as the reactive contrast fuel. Fuels with higher reactivity than CH4 are considered high-reactivity fuels, and vice versa. Common fuel feed arrangements are as follows:

[0092] The multi-fuel mixing nozzle for gas turbines in this embodiment is designed based on the combustion requirements of NH3, but can also burn CH4, H2, and various syngas fuels, greatly expanding the range of applicable fuels. Furthermore, the two cross-jet processes—axial swirling air and fuel, and radial fast-mixing air and upstream mixed gas—significantly promote rapid and thorough fuel mixing.

[0093] Example 2

[0094] Referring to Figures 10 to 12, this embodiment provides a combustion chamber including the multi-fuel mixing nozzle 1 for a gas turbine described in Embodiment 1 above.

[0095] The combustion chamber also includes a fairing 3, a cap 4, and a flame tube 5 connected in sequence along the axial direction. The side of the cap 4 facing the inner cavity of the fairing 3 is the air surface, and the side of the cap 4 facing the inner cavity of the flame tube 5 is the combustion surface.

[0096] The cap 4 is configured to gradually increase in diameter along the axial direction and form a small diameter end and a large diameter end in the axial direction (i.e., the cap 4 is in the form of a frustum cone with a trapezoidal cross-section). The multi-fuel mixing nozzle 1 is installed at the small diameter end, the fairing 3 and the flame tube 5 are respectively installed at the large diameter end, and the cap 4 is provided with a cooling channel connecting the air surface and the combustion surface at the large diameter end.

[0097] Furthermore, the cap 4 includes an upstream wall and a downstream wall that are parallel and spaced apart. The upstream wall is connected to the fairing 3 and the flame tube 5 respectively, and the gap between the periphery of the downstream wall and the flame tube 5 is a cooling channel. The upstream wall is provided with several through impact cooling holes, and the air in the fairing 3 enters the flame tube 5 through the impact cooling holes, the gap between the upstream and downstream walls, and the cooling channel.

[0098] The hood 4 is designed with a double-wall structure, gradually expanding downstream of the shroud 3 and the nozzle. Air inside the shroud 3 enters the gap between the double walls through the impact cooling holes, and then exits through the annular cooling channel between the flame tube 5 and the downstream wall. The swirling incoming air (mixed fuel gas) from the multi-fuel mixing nozzle 1 forms a backflow vortex downstream, and a backflow vortex (cooling air) with the opposite direction is also formed in the vicinity of the connection between the hood 4 and the flame tube 55, forming a backflow zone at the shoulder of the combustion chamber. This promotes the circulation of flue gas inside the combustion chamber and achieves the dual effects of stable combustion and emission reduction.

[0099] Furthermore, an outer casing 2 can be fitted on the outside of the flame tube 5 and the fairing 3. The gap between the outer casing 2 and the flame tube 5 and the fairing 3 is the air input channel. A mixing hole 5-1 communicating with the air input channel can be opened on the flame tube 5. The mixing holes 5-1 are arranged at intervals along the circumference.

[0100] The combustion chamber of this embodiment can achieve relatively low NOx emissions when burning fuels rich in H2 content: by rapidly and fully mixing, the local high equivalence ratio is reduced, thereby increasing the maximum combustion temperature; at the same time, the nozzle with a gradually narrowing outlet, combined with the gradually expanding hood 4, forms a recirculation zone at the shoulder of the combustion chamber, which promotes the circulation of flue gas inside the combustion chamber and achieves the dual effects of stable combustion and emission reduction.

[0101] Example 3

[0102] Referring to Figures 13 to 15 and 17, this embodiment provides a multi-fuel combustion chamber based on the combustion of ammonia-based low-activity fuels, including a combustion chamber and a multi-fuel mixing nozzle for a gas turbine as described in Embodiment 1 above. The multi-fuel mixing nozzle is installed in the combustion chamber. The combustion chamber has an axially extending combustion region, which includes a fuel-rich region, a reburning region, and a burnout dilution region arranged sequentially along the axial direction.

[0103] The multi-fuel mixing nozzle is configured to output a fuel-rich mixture of fuel-rich fuel flow 7 and fuel-rich air flow 8 toward the fuel-rich region and / or to output a reburning mixture of fuel-rich fuel flow 9 and reburning air flow 10 toward the reburning region.

[0104] Of these, the fuel-rich airflow 8 accounts for 5% to 25% of the total air volume, the reburning airflow 10 accounts for 15% to 30% of the total air volume, and the burnout dilution airflow 11, which enters the burnout dilution zone, accounts for 45% to 80% of the total air volume.

[0105] Since the air intake ratio at each point in the combustion chamber cannot be adjusted after the design is completed, and only the fuel intake ratio at each point in the combustion chamber can be adjusted, this embodiment uses a multi-fuel mixing nozzle design to ensure that the air intake ratio in the combustion chamber can satisfy both the combustion of ammonia-based low-activity fuel gas and the combustion of hydrogen-based high-activity fuel gas.

[0106] Under the combustion requirements of ammonia-based low-reactivity fuel gas, both the rich fuel stream 7 and the reburning fuel stream 9 are ammonia-based low-reactivity fuel gas. The ratio of the two is set as follows: the rich fuel stream 7 accounts for 70% to 100% of the total ammonia-based low-reactivity fuel gas, corresponding to a head equivalence ratio between 1 and 2, while the reburning fuel stream 9 accounts for 0% to 30% of the total ammonia-based low-reactivity fuel gas. The ammonia-based low-reactivity fuel gas is configured to enter the swirl premixed gas output channel via a fuel gas premixing channel and / or a fuel gas diffusion channel, thereby achieving stable combustion of the ammonia-based low-reactivity fuel gas in the combustion chamber through premixing / or diffusion combustion.

[0107] Under the combustion requirements of hydrogen-based highly reactive fuel gas, both the rich fuel stream 7 and the reburning fuel stream 9 are hydrogen-based highly reactive fuel gas. The ratio between the two is set as follows: the rich fuel stream 7 accounts for 5% to 25% of the total hydrogen-based highly reactive fuel gas, and the reburning fuel stream 9 accounts for 95% to 75% of the total hydrogen-based highly reactive fuel gas. The hydrogen-based highly reactive fuel gas is configured to enter the swirl premixed gas output channel through the fuel gas diffusion channel, thereby achieving stable combustion of the hydrogen-based highly reactive fuel gas in the combustion chamber through diffusion combustion.

[0108] Furthermore, in this embodiment, after determining the air and ammonia-based low-reactivity fuel distribution ratio in the combustion chamber's fuel-rich zone, reburning zone, and burnout dilution zone based on ammonia-based low-reactivity fuels, hydrogen-based high-reactivity fuel gas or other low-reactivity fuel gas can be further introduced into the fuel gas diffusion channel of the multi-fuel mixing nozzle (for example, based on the introduction of ammonia-based low-reactivity fuel gas into the fuel gas premixing channel, methane or other low-reactivity fuel gas is introduced into the fuel gas diffusion channel; one part of the two low-reactivity fuel gases diffuses, and the majority goes through premixing, which can improve flame stability), thereby achieving multi-fuel co-combustion.

[0109] Example 4

[0110] Referring to 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 embodiment 1.

[0111] The combustion chamber has an axially extending combustion zone, which includes a fuel-rich zone, a reburning zone, and a burnout dilution zone arranged sequentially along the axial direction. The fuel gas premixing channel is configured to output a fuel-rich fuel flow 7 and a reburning fuel flow 9. The air channel is configured to split the total air flow within it and output a fuel-rich air flow 8, a reburning air flow 10, and a burnout dilution air flow 11.

[0112] The fuel-rich stream 7 is configured to mix with the fuel-rich air stream 8 through the multi-fuel mixing nozzle 1 to form a fuel-rich mixture. This fuel-rich mixture is then output to the fuel-rich zone and ignited for fuel-rich combustion. The reburning fuel stream 9 is configured to mix with the reburning air stream 10 to form a reburning mixture. This reburning mixture is then output to the reburning zone to co-combust with the ammonia fuel escaping from the fuel-rich zone. The burnout dilution air stream 11 is configured to be output to the burnout dilution zone to combust with the unburned ammonia fuel entering the burnout dilution zone.

[0113] This embodiment divides the combustion chamber into a sequentially extending fuel-rich zone, a reburning zone, and a burnout dilution zone. The fuel gas premixing channel is configured to output a fuel-rich fuel stream 7 and a reburning fuel stream 9, and the air channel is configured to output a fuel-rich air stream 8, a reburning air stream 10, and a burnout dilution air stream 11. The fuel-rich fuel stream 7 and the fuel-rich air stream 8 are mixed and output to the fuel-rich zone, and the reburning fuel stream 9 and the reburning air stream 10 are mixed and output to the reburning zone. This ensures that the equivalence ratio in the fuel-rich zone, where most of the NH3 fuel is involved, is controlled at a high value close to the combustible limit, which greatly reduces NOx emissions. The downstream reburning mixed stream is added in turn, and the equivalence ratio in the reburning zone is controlled at a low value close to the combustible limit, thereby effectively controlling the cumulative nitrogen oxide emissions at the outlet and keeping the emissions within an acceptable low range.

[0114] The specific structure of the combustion chamber in this embodiment will be further described below:

[0115] In this embodiment, the combustion chamber includes a first combustion chamber section and an outlet contraction section arranged and connected along the axial direction. The fuel-rich 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.

[0116] Specifically, the combustion chamber can be a flame tube 5, which is divided along the axial direction into a larger diameter section (corresponding to the first combustion chamber section mentioned above) and a smaller diameter section (corresponding to the outlet contraction section mentioned above).

[0117] In this embodiment, axially, the end face of the first combustion chamber section furthest from the burnout dilution region is the inlet end face. The rich fuel mixture is configured to be output axially to the rich fuel region via the inlet end face. The reburning mixture is configured to be output to the reburning region via the wall of the first combustion chamber section, with the output direction perpendicular to the axial direction; alternatively, the reburning mixture is configured to be split and output to the reburning region via the walls of the first combustion chamber section, with the output direction perpendicular to the axial direction. The burnout dilution airflow 11 is configured to be output to the burnout dilution region via the outlet contraction section.

[0118] The aforementioned inlet end face can be a cap 4 installed on the flame tube 5. The aforementioned rich fuel mixture enters the rich fuel region through the cap 4, and the reburning mixer enters the reburning region through the circumferential upward side wall of the flame tube 5.

[0119] In this embodiment, the combustion chamber may further include an outer casing 2 and a rectifier, which may specifically be a fairing 3.

[0120] Both the fairing 3 and the aforementioned flame tube 5 are arranged within the inner cavity of the outer casing 2. The first end of the fairing 3 is connected to the end of the outer casing 2 near the fuel-rich region, and the second end of the fairing 3 is connected to the end of the flame tube 5 near the fuel-rich region (i.e., the end of the flame tube 5 with the cap 4 installed). Furthermore, the inner wall of the outer casing 2, the fairing components, and the combustion chamber cooperate to form the aforementioned air passage. This air passage surrounds the entire first combustion chamber section of the flame tube 5 and only part of the outlet contraction section, thereby enabling the introduction of air into the burnout dilution region through openings in the outlet contraction section. The airflow rate of this portion can be controlled by setting a flow valve or similar means.

[0121] The inner cavity of the fairing 3 can be combined with the combustion chamber end cover 6 of the outer casing 2 and the cap 4 to form a fuel-rich air input cavity that connects the above-mentioned air passage.

[0122] In this embodiment, the fuel gas premixing channel includes a fuel-rich fuel line corresponding to the fuel-rich fuel flow 7 and at least one reburning fuel line corresponding to the reburning fuel flow 9. The combustion chamber also includes a fuel-rich zone nozzle 1A and at least one reburning swirl starter (corresponding one-to-one with the reburning fuel line). Both the fuel-rich zone nozzle 1A and the reburning swirl starter can be the aforementioned multi-fuel mixing nozzle 1.

[0123] The fuel-rich zone nozzle 1A can be arranged in the aforementioned fuel-rich air inlet chamber and connected to the cap 4. The fuel-rich zone nozzle 1A is configured to receive the fuel-rich fuel flow 7 (the aforementioned fuel-rich pipeline passes through the combustion chamber end cap 6 of the outer casing 2, extends into the fuel-rich air inlet chamber, and is connected to the fuel inlet end of the fuel-rich zone nozzle 1A) and the fuel-rich air flow 8 (the air inlet end of the fuel-rich zone nozzle 1A can be directly connected to the fuel-rich air inlet chamber) and perform swirling premixing to form a fuel-rich mixture. The mixture is then ejected into the fuel-rich zone through the opening of the fuel-rich zone nozzle 1A on the second side of the cap 4, with the output direction along the axis of the flame tube 5.

[0124] The reburning zone nozzle 1B can be configured to surround the output path of the rich fuel mixture and connect to the combustion chamber (i.e., installed around the circumferential sidewall of the flame tube 5). The reburning zone nozzle 1B is configured to receive the reburning fuel flow 9 (the aforementioned reburning fuel pipeline extends through the outer casing 2 into the air passage and connects to the fuel input end of the reburning zone nozzle 1B) and the reburning air flow 10 (the air input end of the reburning zone nozzle 1B can be directly connected to the air passage) for swirling premixing to form a reburning mixture, and output it to the reburning zone. The output direction can be perpendicular to the axis of the flame tube 5. The number of the aforementioned reburning zone nozzles 1B can be 4 to 8, specifically 6, evenly arranged circumferentially.

[0125] Furthermore, at least one mixing hole 5-1 can be provided on the outlet contraction section of the flame tube 5, arranged around the output path of the rich fuel mixture. The burnout dilution air flow 11 (i.e., the airflow entering the through hole in the air channel) is output to the burnout dilution region through the mixing hole 5-1, and the output direction can be perpendicular to the axis of the flame tube 5. The number of mixing holes 5-1 can be 4 to 8, and they are evenly arranged in the circumferential direction.

[0126] Based on this, the combustion chamber of this embodiment achieves the following beneficial effects:

[0127] 1. Easy start-up: The fuel-rich zone at the head adopts a swirl burner (multi-fuel mixing nozzle 1), forming a recirculation zone downstream, which is beneficial for ignition and flame stabilization. By reasonably setting the fuel quantity under ignition conditions, the equivalence ratio near the head igniter is distributed within a stable combustible range, enabling the gas turbine to start at room temperature, simplifying the ignition start-up system, and without increasing other types of exhaust gas emission sources.

[0128] 2. Improved combustion stability: Through the multi-stage arrangement of fuel and air, a fuel-rich zone, a reburning zone, and a burnout dilution zone are formed in the combustion chamber. The local equivalence ratio of each zone has a large range. In particular, the equivalence ratio of the fuel-rich zone has a large downward space within the stable combustion range. The change range of the local local equivalence ratio when the speed and load increase can be limited to the combustible range, thereby achieving the effect of stable combustion throughout the entire process.

[0129] In summary, compared with existing technologies, this technical solution, through the multi-stage arrangement of fuel and air, forms a fuel-rich zone, a reburning zone, and a burnout dilution zone in the combustion chamber. By rationally setting the equivalence ratio of each zone, it can achieve room temperature ignition and start-up, improve combustion stability and efficiency, and reduce nitrogen oxide emissions. This enables stable, efficient, and clean combustion of NH3 in gas turbines, facilitating the large-scale application of ammonia in the gas turbine field.

[0130] Example 5

[0131] Referring to Figure 16, this embodiment adjusts the arrangement of the combustion chamber based on Embodiment 3 described above, as follows:

[0132] The combustion chamber includes a second combustion chamber section, a third combustion chamber section, and an outlet contraction section arranged axially and connected. 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 fuel-rich region is located in the second combustion chamber section, while the reburning region and the burnout dilution region are located in the third combustion chamber section.

[0133] In the axial direction, the end face of the second combustion chamber section away from the burnout and dilution region is the inlet end face, and the end face of the third combustion chamber section away from the burnout and dilution region cooperates with the second combustion chamber section to form a stepped end face.

[0134] The fuel-rich mixture is configured to be output axially through the inlet end face to the fuel-rich 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 each enter the reburning region axially through the stepped end face. The burnout dilution air flow 11 is configured to be output through the wall of the third combustion chamber section to the burnout dilution region, and the output direction is perpendicular to the axial direction, or the burnout dilution air flow 11 is configured to be split and each output through the wall of the third combustion chamber section to the burnout dilution region, and the output direction is perpendicular to the axial direction.

[0135] Specifically, the combustion chamber can be a flame tube 5, which includes three sections. The diameters of the first and third sections are smaller than those of the middle second section. The stepped end face can be formed without a transition section between the first and second sections. The stepped end face can be an annular cap 4, while a transition section can be provided between the second and third sections.

[0136] The fairing 3 can be configured to be directly connected to the stepped end face of the second section of the cylinder, so that the space between the stepped end face and the first section of the cylinder is also located in the aforementioned rich air input chamber (essentially a chamber shared by rich air and reburning air); the aforementioned rich area nozzle 1A can still be set on the cap 4 of the first section of the cylinder, and the rest of the arrangement is similar to the embodiment; the aforementioned reburning area nozzle 1B can be arranged on the stepped end face, and the aforementioned reburning fuel pipeline passes through the combustion chamber end cover 6 of the outer casing 2 and extends into the rich air input chamber 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 connected to the rich air input chamber) to swirl and premix to form a reburning mixture, and output to the reburning area, and the output direction can be parallel to the axis of the flame tube 5.

[0137] In this arrangement, the partial burnout dilution zone can be moved forward into the second section of the cylinder, so the mixing hole 5-1 mentioned above can be arranged at the end of the second section of the cylinder.

[0138] In this embodiment, the two levels of the fuel-rich zone and the reburning zone are arranged in a radial stepped manner to achieve relative isolation and independence in physical space, thereby reducing the mutual influence between the two zones.

[0139] Example 6

[0140] This embodiment provides a combustion method based on the above embodiments. This combustion method can be applied to a combustion chamber for a gas turbine with a multi-fuel mixing nozzle as described in Embodiment 1, and can also be applied to combustion chambers as described in Embodiments 2 to 4. The method is as follows:

[0141] A combustion chamber is provided with a fuel-rich zone, a reburning zone, and a burnout dilution zone arranged sequentially along the axial direction. A fuel-rich mixture formed by a fuel-rich flow 7 and a fuel-rich air flow 8 is introduced into the fuel-rich zone, a reburning mixture formed by a reburning fuel flow 9 and a reburning air flow 10 is introduced into the reburning zone, and a burnout dilution air flow 11 is introduced into the burnout dilution zone.

[0142] The fuel quantity of the fuel-rich fuel stream 7 accounts for 70% to 100% of the total fuel quantity of the fuel-rich fuel stream 7 and the reburning fuel stream 9; the total air quantity is 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, with the air quantity of the fuel-rich air stream 8 accounting for 5% to 25% of the total air quantity and the air quantity of the reburning air stream 10 accounting for 15% to 30% of the total air quantity.

[0143] The combustion method in this embodiment uses NH3 fuel as a starting point and can burn H2, CH4 and other synthesis gases.

[0144] The technical principle of the combustion chamber in this embodiment will be further explained below:

[0145] Referring to Figure 14, the entire combustion chamber is divided into a fuel-rich zone, a reburning zone, and a burnout dilution zone, each serving a different functional purpose.

[0146] The head-end rich combustion zone employs a multi-fuel mixing nozzle 1, creating a recirculation zone downstream, which is beneficial for ignition and flame stabilization. By rationally setting the fuel quantity under ignition conditions, the equivalence ratio near the head igniter is distributed within a stable combustible range, enabling the gas turbine to achieve ambient temperature ignition and start-up, simplifying the ignition and start-up system, and without increasing other types of exhaust gas emission sources. Furthermore, in the rich combustion zone, to suppress nitrogen oxide emissions and maintain stable combustion under variable load conditions, the equivalence ratio in this zone is set close to the high value of the combustible limit. Therefore, 5-25% air and 70-100% fuel are arranged in the rich combustion zone. As shown in Figure 13, in the atmospheric pressure premixed combustion of ammonia, NOx exhibits a trend of first increasing and then decreasing with the increase of the equivalence ratio, peaking around an equivalence ratio of 0.9. In the region above an equivalence ratio of 1.2, nitrogen oxide emissions tend to be 0 ppm, thus achieving the goal of emission reduction.

[0147] When the air volume changes little during the load adjustment of a gas turbine, the fuel volume varies considerably. For example, during the transition from full-speed no-load to full-load, the equivalence ratio across the entire combustion chamber increases exponentially. Therefore, the equivalence ratio in the fuel-rich region under full load is set at a high value close to the combustible limit. This allows for a greater downward range of the stable combustion range of the fuel-rich region's equivalence ratio during load changes, especially load reduction. The range of the fuel-rich region's equivalence ratio can be limited to the combustible region, thus achieving stable combustion throughout the entire process.

[0148] In the reburning zone, the main task is to rapidly consume NH3 and release fuel heat. The equivalence ratio after the reburning zone is set close to the low value of the combustible limit. As shown in Figure 13, in the atmospheric pressure premixed combustion of ammonia, the residual NH3 at the outlet increases with the increase of the equivalence ratio. Predictably, since the equivalence ratio in the fuel-rich zone is set close to the high value of the combustible limit, unburned NH3 will escape from the fuel-rich zone. Therefore, 15-30% air and 0-30% NH3 are arranged in the downstream reburning zone, so that the local local equivalence ratio variation range before and after the reburning zone spans from the high value of the fuel-rich zone to the low value of the fuel-lean zone, but the overall equivalence ratio in the reburning zone is in a stable combustion zone, thereby rapidly consuming NH3 fuel.

[0149] Structurally, the two levels of the fuel-rich zone and the reburning zone are arranged at different depths along the axial direction or in a stepped manner along the radial direction to achieve relative isolation and independence in physical space and reduce mutual influence between the two zones.

[0150] Finally, upon entering the burnout dilution zone, the addition of 45-80% air further burns the unburned NH3, improving combustion efficiency. Simultaneously, rapid dilution achieves the cooling purpose, freezing the formation of nitrogen oxides.

[0151] Based on this, the combustion method of this embodiment achieves the following beneficial effects.

[0152] 1. Low NOx Emissions: As shown in Figure 13, in the atmospheric pressure premixed combustion of ammonia, NOx emissions show a trend of first increasing and then decreasing with the increase of the equivalence ratio, with the peak occurring around an equivalence ratio of 0.9. In the range above an equivalence ratio of 1.2, NOx emissions tend to be zero. Through multi-stage air and fuel arrangement, the air content in the fuel-rich zone is 5-25%, and the fuel content is 70-100%, ensuring that the equivalence ratio in the fuel-rich zone, where the majority of NH3 fuel participates, is controlled close to the high value of the combustible limit, thus significantly reducing NOx emissions. Downstream, with the subsequent addition of 15-30% air and 0-30% fuel, the equivalence ratio in the recombustion zone is controlled close to the low value of the combustible limit, also deviating from the peak NOx equivalence ratio of 0.9, thereby effectively controlling the cumulative NOx emissions at the outlet, keeping emissions within an acceptable low range.

[0153] 2. Improving Combustion Efficiency: To reduce NOx, the equivalence ratio in the fuel-rich zone is controlled at a high value close to the combustible limit, while the residual NH3 at the outlet increases with the increase of the equivalence ratio, as shown in Figure 1. Predictably, unburned NH3 will escape from the fuel-rich zone. Therefore, 15-30% air and 0-30% NH3 are arranged in the reburning zone, so that the local equivalence ratio before and after the reburning zone changes from a high value of fuel-rich to a low value of fuel-lean, but the overall equivalence ratio in the reburning zone remains within a stable combustion range, thus rapidly consuming the NH3 fuel. Upon entering the burnout dilution zone, the addition of 45-80% air further burns the unburned NH3, improving combustion efficiency, while rapid dilution achieves cooling, freezing the formation of nitrogen oxides.

[0154] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they shall still fall within the protection scope of the present invention.

Claims

1. A multi-fuel mixing nozzle for a gas turbine, characterized in that, The fuel nozzle body includes a fuel gas premixing channel, a swirling premixed gas output channel, a fuel gas diffusion channel, and a radial fast-mixing air channel. Along the gas flow direction within the swirling premixed gas output channel, the output ends of the fuel gas premixing channel, the fuel gas diffusion channel, and the radial fast mixed air channel are sequentially connected to the swirling premixed gas output channel. The fuel gas premixing channel is configured to output premixed fuel gas with low reactivity in a premixed manner to the upstream of the swirl premixed gas output channel. The fuel gas diffusion channel is configured to output fuel gas with high reactivity or low reactivity in a diffusion manner to the downstream of the swirl premixed gas output channel; 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.

2. The multi-fuel mixing nozzle for a gas turbine as described in claim 1, characterized in that, At least a portion of the swirling premixed gas output channel is configured with a diameter that gradually decreases along the airflow direction to accelerate the gas flow rate within it.

3. The multi-fuel mixing nozzle for a gas turbine as described in claim 1, characterized in that, The swirl premixed gas output channel includes a fuel gas premixing channel and a premixed air channel; The premixed air channel is formed by the spacing between adjacent swirl blades on the fuel nozzle body. The fuel gas premixed channel is configured to extend within the swirl blades and be injected from the surface of the swirl blades, outputting low-reactivity fuel gas toward the premixed air channel. The swirl blades are configured to guide the premixed air entering the premixed air channel to premix with the low-reactivity 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 or axial swirl.

4. The multi-fuel mixing nozzle for a gas turbine as described in claim 3, characterized in that, The swirl blades can be radial swirl blades or axial swirl blades.

5. The multi-fuel mixing nozzle for a gas turbine as described in claim 1, characterized in that, The output end of the fuel gas diffusion channel is connected to 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 fast-mixing air channel is connected to the swirling premixed gas output channel through a plurality of discretely arranged radial fast-mixing air injection ports, and the radial fast-mixing air injection ports are located downstream of the fuel gas diffusion injection holes and are staggered in the circumferential direction along the swirling direction.

6. The multi-fuel mixing nozzle for a gas turbine as described in claim 1, characterized in that, The low-reactivity fuel gas is ammonia, methane, or a synthesis gas with low hydrogen content.

7. The multi-fuel mixing nozzle for a gas turbine as described in claim 1, characterized in that, The highly reactive fuel gas is hydrogen or syngas with a high hydrogen content.

8. A multi-fuel combustion chamber based on the combustion of ammonia-based low-activity fuels, characterized in that, Includes a combustion chamber and a multi-fuel mixing nozzle for a gas turbine as described in any one of claims 1 to 7, installed in the combustion chamber; The combustion chamber is provided with an axially extending combustion zone, which includes a fuel-rich zone, a reburning zone, and a burnout dilution zone arranged sequentially along the axial direction. The multi-fuel mixing nozzle is configured to output a fuel-rich mixture of fuel-rich fuel flow and fuel-rich air flow toward the fuel-rich region and / or to output a reburning mixture of reburning fuel flow and reburning air flow toward the reburning region. The fuel-rich airflow accounts for 5% to 25% of the total air volume, the reburning airflow accounts for 15% to 30% of the total air volume, and the burnout dilution airflow entering the burnout dilution zone accounts for 45% to 80% of the total air volume.

9. The multi-fuel combustion chamber based on the combustion of ammonia-based low-activity fuels as described in claim 8, characterized in that, The rich fuel stream and the reburning fuel stream are ammonia-based low-activity fuel gases. The rich fuel stream accounts for 70% to 100% of the total ammonia-based low-activity fuel gas, corresponding to a rich state with a head equivalence ratio between 1 and 2. The reburning fuel stream accounts for 0% to 30% of the total ammonia-based low-activity fuel gas. The ammonia-based low-activity 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.

10. The multi-fuel combustion chamber based on the combustion of ammonia-based low-activity fuels as described in claim 8, characterized in that, The fuel-rich stream and the reburning stream are hydrogen-based highly reactive fuel gases. The fuel-rich stream accounts for 5% to 25% of the total amount of hydrogen-based highly reactive fuel gases, and the reburning stream accounts for 95% to 75% of the total amount of hydrogen-based highly reactive fuel gases. The hydrogen-based highly reactive fuel gas is configured to enter the swirling premixed gas output channel via the fuel gas diffusion channel.

11. The multi-fuel combustion chamber based on the combustion of ammonia-based low-activity fuels as described in claim 8 or 9, characterized in that, After determining the air and ammonia-based low-reactivity fuel gas distribution ratio in the combustion chamber's fuel-rich zone, reburning zone, and burnout dilution zone based on ammonia-based low-reactivity fuel, hydrogen-based high-reactivity fuel gas or other low-reactivity fuel gas is introduced through the nozzle fuel gas diffusion channel to achieve multi-fuel co-firing.

12. A combustion chamber, characterized in that, Includes at least one multi-fuel mixing nozzle for a gas turbine as described in any one of claims 1 to 7; Also includes: The combustion chamber has an axially extending combustion zone, which includes a fuel-rich zone, a reburning zone, and a burnout dilution zone arranged sequentially along the axial direction. A fuel gas passage configured to output a fuel-rich fuel flow and a reburning fuel flow; An air passage configured to split the total airflow within it and output a fuel-rich airflow, a reburning airflow, and a burnout dilution airflow; The fuel-rich flow is configured to mix with the fuel-rich air flow in the multi-fuel mixing nozzle to form a fuel-rich mixture, which is then output to the fuel-rich region and ignited for fuel-rich combustion. The reburning fuel flow is configured to mix with the reburning air flow in the multi-fuel mixing nozzle to form a reburning mixture, which is then output to the reburning region for co-combustion with the low-reactivity fuel gas escaping from the fuel-rich region. The burnout dilution air flow is configured to be output to the burnout dilution region for combustion with the unburned low-reactivity fuel gas entering the burnout dilution region.

13. The combustion chamber as claimed in claim 12, characterized in that, The multi-fuel mixing nozzles in the fuel-rich zone and the reburning zone are arranged at different depths along the axial direction of the combustion chamber.

14. The combustion chamber as claimed in claim 12, 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.

15. A combustion method, characterized in that, The method is as follows: The method is applied to a combustion chamber comprising a multi-fuel mixing nozzle for a gas turbine as described in any one of claims 1-7, or to a combustion chamber as described in any one of claims 8 to 14. The combustion chamber is provided with a fuel-rich zone, a reburning zone, and a burnout dilution zone arranged sequentially along the axial direction; A fuel-rich mixture formed by a fuel-rich flow and a fuel-rich air flow is input into the fuel-rich region; a reburning mixture formed by a reburning fuel flow and a reburning air flow is input into the reburning region; and a burnout dilution air flow is input into the burnout dilution region. The fuel quantity of the rich fuel stream accounts for 70% to 100% of the sum of the fuel quantities of the rich fuel stream and the reburning fuel stream. The sum of the air volume of the fuel-rich air stream, the reburning air stream, and the burnout dilution air stream constitutes the total air volume. The air volume of the fuel-rich air stream accounts for 5% to 25% of the total air volume, and the air volume of the reburning air stream accounts for 15% to 30% of the total air volume.

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