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

Abstract

The invention discloses a multi-fuel mixing nozzle for a gas turbine, a combustion chamber and a combustion method, and is applied to the technical field of gas turbines. The output ends of a fuel gas premixing channel, a fuel gas diffusion channel and a radial quick mixing air channel are arranged in a fuel nozzle body to be sequentially communicated to a rotational flow premixed gas output channel; when the low-reaction-characteristic fuel gas is combusted, premixed fuel gas containing the low-reaction-characteristic fuel gas is mixed with radial fast-mixing air in the rotational flow premixed gas output channel and output, or the premixed fuel gas is sequentially mixed with high / low-reaction-characteristic fuel gas sprayed out of the fuel gas diffusion channel and the radial fast-mixing air and output, so that stable combustion is achieved; when only the high-reaction-characteristic fuel gas is combusted, the high-reaction-characteristic fuel gas is output into the rotational flow premixed gas output channel through the fuel gas diffusion channel, and the high-reaction-characteristic fuel gas, upstream rotational flow air and downstream radial fast mixing air are subjected to cross jet flow for multiple times, so that fast mixing and low-nitrogen combustion are achieved.

Description

Technical Field

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

[0002] Over the past few decades, the extensive use of hydrocarbon fuels has produced greenhouse gases CO2 and NO x The emission of pollutants, including carbon dioxide, has led to global warming and various environmental pollution, 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 accelerated advancement of emission reduction and decarbonization in the energy and power industry, the demand for clean alternative fuels in gas turbines has become increasingly prominent, which means that gas turbine combustion technology must also be upgraded accordingly, and at the same time, the corresponding combustion nozzles and combustion chambers must be upgraded.

[0003] Hydrogen is one of the most popular carbon-free fuels and has been widely used in the field of fuel cells as a highly reactive fuel gas. Figure 1 As shown in Figure 1, replacing traditional fuels with hydrogen greatly reduces the emission intensity of CO2. However, hydrogen cannot be found in nature and must be produced. It is flammable and explosive along with its high fuel activity. Another consideration is the high cost of liquefying and transporting liquid hydrogen. This combination of economic and safety factors hinders the widespread use of hydrogen at present.

[0004] As a carbon-free fuel, NH3 is another effective hydrogen carrier with a higher hydrogen density per unit volume than liquid hydrogen. In addition, due to more than 100 years of commercial demand, current large-scale production is very mature; on the other hand, it is easy to liquefy, which significantly reduces storage, transportation and related development costs. However, the low combustion rate and high fuel NO x Emissions inhibit the large-scale use of NH3 in the following aspects: (1) Low flame propagation speed: The flame speed of NH3 at atmospheric pressure and ambient temperature is relatively low, only 7 cm / s, which easily leads to low combustion efficiency and incomplete combustion; (2) High minimum ignition energy: The minimum ignition energy of NH3 is 8mJ, which is about 40 times that of H2. Ignition requires higher spark energy; (3) High ignition temperature: The ignition temperature of NH3 is higher than that of other common fuels; (4) Narrow flammability limit: Compared with H2, the flammability limit of NH3 is much narrower, which may cause misfire under lean or rich combustion conditions; (5) Difficulty in starting: Due to the poor reactivity of ammonia fuel, ignition and starting often require the use of starting fuel. For example, Japanese manufacturers use carbon-containing fuels such as kerosene, diesel, and methane for starting, which not only increases investment but also creates carbon emission problems. If hydrogen is used for starting, the system complexity will also increase.

[0005] (6) Potential high NO x Emissions: Ammonia fuel contains nitrogen, except for thermal NO x In addition, more fuel-type NO x , and the unreasonable equivalence ratio distribution in the combustion chamber will also aggravate this high emission trend.

[0006] With the advancement of combustion technology, the roadmap for the use of alternative clean carbon-free fuels has become roughly clear, that is, at this stage, the focus is on overcoming the low fuel activity of NH3 and high NO x Under the premise of solving the emission problem, priority should be given to the development and use of NH3 fuel; after solving the problems of large-scale production, storage and transportation of hydrogen, we will eventually turn to hydrogen as the ultimate energy source.

[0007] At the same time, it is necessary to be aware of the differences in energy distribution, mining and use among different countries. There are still many uncertainties surrounding the alternative clean fuels available for the gas-fired power generation industry, and it is even less likely that there will be only one single fuel in various usage scenarios worldwide. This means that the need for fuel flexibility will be an important design element for new gas turbines, which is more evident in industries such as petroleum, refining, textiles, printing and dyeing, and metallurgy. These scenarios have huge demands for electricity and steam, while at the same time, a wide variety of fuel types can be provided. However, general combustion chambers only support the combustion of specific fuels. Replacing different fuels will cause huge differences in the Wobbe index, and it is impossible to guarantee the release of the same heat load at the same combustion pressure. At the same time, changes in fuel activity will lead to changes in the temperature field, and aspects such as combustion stability will be impacted. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a multi-fuel mixing nozzle, a combustion chamber and a combustion method for a gas turbine, so as to solve the problem that the existing fuel nozzle cannot match the combustion of multiple fuels.

[0009] To solve the above problems, the technical solution of the present invention is: A multi-fuel mixing nozzle for a gas turbine of the present invention comprises a fuel nozzle body, wherein the fuel nozzle body is provided with a fuel gas premixing channel, a swirl premixed gas output channel, a fuel gas diffusion channel and a radial fast mixing air channel; 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 passage is located downstream of the output end of the fuel gas diffusion passage, and the radial fast-mixing air passage is configured to output radial fast-mixing air to the swirl premixed gas output passage.

[0010] In the multi-fuel mixing nozzle for a gas turbine of the present invention, at least part of the swirl premixed gas output channel is configured to have a diameter that gradually decreases along the airflow direction to accelerate the gas flow rate therein.

[0011] The multi-fuel mixing nozzle for a gas turbine of the present invention, the fuel gas premixing passage comprises a premixing fuel gas passage and a premixing air passage; The intervals between adjacent swirl blades on the fuel nozzle body form the premixed air channel, and the premixed fuel gas channel is configured to extend within the swirl blades and spray from the surfaces of the swirl blades to output low-reactivity characteristic fuel gas toward the premixed air channel; the swirl blades are configured to guide the premixed air entering the premixed 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.

[0012] In the multi-fuel mixing nozzle for a gas turbine of the present invention, the swirl blades can be radial swirl blades or axial swirl blades.

[0013] The multi-fuel mixing nozzle for a gas turbine of the present invention is characterized in that 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 holes, and the radial fast mixing air channel injection holes are located downstream of the fuel gas diffusion injection holes and are staggered in the circumferential direction along the swirl direction.

[0014] In the multi-fuel mixing nozzle for a gas turbine of the present invention, the low-reactivity fuel gas is ammonia or methane or a synthetic gas with a low hydrogen content.

[0015] In the multi-fuel mixing nozzle for a gas turbine of the present invention, the fuel gas with high reactivity characteristics is hydrogen or a synthesis gas with a high hydrogen content.

[0016] A multi-fuel combustion chamber based on the combustion of ammonia low-activity fuel of the present invention comprises a combustion chamber and any one of the above-mentioned multi-fuel mixing nozzles for a gas turbine 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.

[0017] In the multi-fuel combustion chamber based on the combustion of ammonia low-activity fuel of the present invention, the rich fuel flow and the reburning fuel flow are ammonia low-activity fuel gas, the rich fuel flow accounts for 70% to 100% of the total amount of ammonia low-activity fuel gas, corresponding to the rich state with the head equivalence ratio between 1 and 2, and the reburning fuel flow accounts for 0% to 30% of the total amount of ammonia low-activity fuel gas; The ammonia 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.

[0018] In the multi-fuel combustor based on the combustion of ammonia low-activity fuel of the present invention, the rich fuel flow and the reburning fuel flow are hydrogen high-activity fuel gas, the rich fuel flow accounts for 5% to 25% of the total amount of hydrogen high-activity fuel gas, and the reburning fuel flow accounts for 95% to 75% of the total amount of hydrogen 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.

[0019] The multi-fuel combustion chamber based on the combustion of ammonia low-activity fuel of the present invention, after determining the distribution ratio of air and ammonia low-activity fuel gas in the rich combustion area, reburning area and burnout dilution area of ​​the combustion chamber based on the ammonia low-activity fuel, introduces the hydrogen high-reactivity fuel gas or other low-reactivity fuel gas from the nozzle fuel gas diffusion channel to achieve multi-fuel co-firing.

[0020] A combustion chamber of the present invention comprises at least one multi-fuel mixing nozzle for a gas turbine as described in any one of the above; 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.

[0021] In the combustion chamber of the present invention, 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.

[0022] In the combustion chamber of the present invention, the multi-fuel mixing nozzles in the fuel-rich area and the reburning area are arranged in a stepped manner along the radial direction of the combustion chamber.

[0023] A combustion method of the present invention is applied to a combustion chamber comprising any one of the multi-fuel mixing nozzles for a gas turbine described above, or applied to any one of the combustion chambers described above, and 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.

[0024] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art: 1. In one embodiment of the present invention, 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 in a fuel nozzle body, and the output ends of the fuel gas premixing channel, the fuel gas diffusion channel and the radial fast mixing air channel are arranged to be connected to the swirl premixing gas output channel in sequence; 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 premixing gas output channel and output, or is successively mixed with the high / low-reactivity fuel gas and the radial fast mixing air ejected from the fuel gas diffusion channel and output, so as to achieve stable combustion; when only high-reactivity fuel gas is burned, the high-reactivity fuel gas is output to the swirl premixing gas output channel through the fuel gas diffusion channel, and crosses the jets with the upstream swirl air and the downstream radial fast mixing air for multiple times, so as to achieve rapid mixing and low-nitrogen combustion; so that the multi-fuel mixing nozzle can not only burn low-reactivity fuel gas such as NH3 alone, but also burn high-reactivity fuel gas such as H2 alone, and can also burn low-reactivity fuel gas and high-reactivity fuel gas at the same time, thereby improving fuel flexibility.

[0025] 2. In one embodiment of the present invention, the space in the combustion chamber is divided into a rich combustion area, a reburning area and a burnout dilution area which extend in sequence, the fuel gas premixing channel is configured to output a rich combustion fuel flow and a reburning fuel flow, the air channel is configured to output a rich combustion air flow, a reburning air flow and a burnout dilution air flow, the rich combustion fuel flow and the rich combustion air flow are mixed and output to the rich combustion area, the reburning fuel flow and the reburning air flow are mixed and output to the reburning area, and the proportions of each fuel flow and each air flow are adjusted; so that the equivalence ratio in the rich combustion area where most of the NH3 fuel is involved is controlled to be close to the high value of the flammable limit, so that NO x Emissions are greatly reduced, and the reburning mixed flow is relayed downstream, and the equivalence ratio in the reburning zone is controlled near a low value close to the flammable limit, thereby effectively controlling the cumulative nitrogen oxide emissions at the outlet, keeping the emissions within an acceptable low range, while ensuring stable combustion and burnout. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the effect of H2 content in CH4 fuel on CO2 emission intensity; Figure 2 This is a schematic diagram of a multi-fuel fast mixing nozzle according to a first embodiment of the present invention; Figure 3 A cross-sectional view of a multi-fuel rapid mixing nozzle according to a first embodiment of the present invention; Figure 4 Another cross-sectional view of the multi-fuel fast mixing nozzle of the first embodiment of the present invention; Figure 5 AA cross-sectional view of the multi-fuel fast mixing nozzle of the first embodiment of the present invention; Figure 6 It is a BB cross-sectional view of the multi-fuel fast mixing nozzle of the first embodiment of the present invention; Figure 7 It is a CC cross-sectional view of the multi-fuel fast mixing nozzle of the first embodiment of the present invention; Figure 8 DD cross-sectional view of the multi-fuel fast mixing nozzle of the first embodiment of the present invention; Fig. 9 It is an EE cross-sectional view of a multi-fuel fast mixing nozzle according to Embodiment 1 of the present invention; Fig.10 is a cross-sectional view of a combustion chamber according to a second embodiment of the present invention; Fig.11 is another cross-sectional view of the combustion chamber of the second embodiment of the present invention; Fig.12 It is a structural schematic diagram of a combustion chamber cap according to the second embodiment of the present invention; Fig.13 This is a schematic diagram of the effect of changes in the equivalence ratio on the outlet flue gas components during the normal pressure premixed combustion of NH3; Fig.14 It is a schematic diagram of the multi-stage combustion technology of the combustion chamber of the third embodiment and the fourth embodiment of the present invention; Fig.15 It is a structural cross-sectional view of the combustion chamber of the third embodiment and the fourth embodiment of the present invention; Fig.16 It is a structural cross-sectional view of a combustion chamber according to a fifth embodiment of the present invention; Fig.17 This is a schematic diagram of the principle of the combustion chamber of the third embodiment of the present invention.

[0027] Explanation of the reference numerals: 1. Multi-fuel mixing nozzle; 1A. Rich fuel area nozzle; 1B. Reburning area nozzle; 1-1. Inlet pipe of fuel gas diffusion channel; 1-2. Radial diffusion pipe of fuel gas diffusion channel; 1-3. Axial delivery pipe of fuel gas diffusion channel; 1-4. Radial return pipe of fuel gas diffusion channel; 1-5. Annular fuel gas output channel; 1-6. Fuel gas diffusion injection hole; 1-7. Inlet pipe of premixed fuel gas channel; 1-8. Axial sandwich channel of premixed fuel gas channel; 1-9. Radial diffusion pipe of premixed fuel gas channel; 1-10. Axial delivery pipe of premixed fuel gas channel; 1-11. Injection hole of premixed fuel gas channel; 1-12. Fast-mix air radial delivery pipe; 1-13, fast-mix air axial delivery pipe; 1-14, radial fast-mix air channel injection port; 1-15, swirl blade; 1-16, tangential air channel; 1-17, swirl premixed gas output channel; 1-18, nozzle tapered outer wall; 2, outer casing; 3, fairing; 4, cover; 4-1, upstream wall; 4-2, impact cooling holes; 4-3, downstream wall; 4A, center cover; 4B, annular cover; 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 DESCRIPTION

[0028] The following is a further detailed description of 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. The advantages and features of the present invention will become more apparent from the following description.

[0029] Embodiment 1 See also Figures 2 to 9 In one embodiment, a multi-fuel mixing nozzle 1 for a gas turbine includes a fuel nozzle body, in which a swirl premixed gas output channel 1-17, a fuel gas premixed gas channel, a fuel gas diffusion channel, and a radial fast mixing air channel are provided. Along the gas flow direction (from upstream to downstream) in the swirl premixed gas output channel, the output ends of the fuel gas premixed gas channel, the fuel gas diffusion channel, and the radial fast mixing air channel are sequentially connected to the swirl premixed gas output channel 1-17.

[0030] The fuel gas premixing channel is configured to output premixed fuel gas (i.e., fuel gas premixed with air) with low reactivity characteristics (such as NH3, low hydrogen 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 hydrogen 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 in a diffusion manner (the diffusion mode is non-premixing, which means that the fuel and air are not premixed, and the two are mixed and burned after being sent to the gas area. Here, the corresponding fuel gas is directly output to the swirl premixed gas output channel 1-17). The output end of the radial fast-mix 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-mix air channel is configured to output radial fast-mixed air to the swirl premixed gas output channel 1-17.

[0031] In this embodiment, a swirl premixed gas output channel 1-17, a fuel gas premixed gas channel, a fuel gas diffusion channel and a radial fast-mixed air channel are arranged in the fuel nozzle body, and the output ends of the fuel gas premixed gas channel, the fuel gas diffusion channel and the radial fast-mixed air channel are arranged to be connected to the swirl premixed gas output channel in sequence, the fuel gas premixed gas channel outputs premixed fuel gas containing low-reactivity characteristic fuel gas to the upstream of the swirl premixed gas output channel 1-17, the fuel gas diffusion channel outputs low-reactivity characteristic fuel gas or high-reactivity characteristic fuel gas to the downstream of the swirl premixed gas output channel 1-17, and the radial fast-mixed air channel outputs radial fast-mixed 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 offset in the circumferential direction along the swirl direction, so as to realize cross-jetting of the diffused fuel; When burning low-reactivity fuel gas, the premixed fuel gas containing low-reactivity fuel gas is mixed with radial fast-mix air in the swirl premix gas output channel and output, or is mixed with high / low-reactivity fuel gas and radial fast-mix air ejected from the fuel gas diffusion channel in sequence and output, so as to achieve stable combustion; when only high-reactivity fuel gas is burned, the high-reactivity fuel gas is output to the swirl premix gas output channel through the fuel gas diffusion channel, and cross-jetted with the upstream swirl air and downstream radial fast-mix air for multiple times, so as to achieve rapid mixing and low-nitrogen combustion; the multi-fuel mixing nozzle can not only burn low-reactivity fuel gas such as NH3 alone, but also burn high-reactivity fuel gas such as H2 alone, and can also burn low-reactivity fuel gas and high-reactivity fuel gas at the same time, which greatly broadens the types of applicable fuels and improves fuel flexibility.

[0032] The specific structure of the multi-fuel mixing nozzle for the gas turbine of this embodiment is further described below: In this embodiment, at least part of the above-mentioned swirl premixed gas output channel is configured to gradually reduce its diameter along the direction of airflow, so that the gas flow rate of the premixed fuel gas and / or high-reactivity fuel gas entering therein 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 reduce its diameter along the direction of airflow, the premixed fuel gas can be configured to input the annular mixing section, and the fuel gas of the fuel gas diffusion channel can be configured to input 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 can specifically be an annular gap formed between the nozzle tapered outer wall 1-18 located on the outside and the inner solid part of the fuel nozzle body located on the inside.

[0033] Furthermore, the above-mentioned premixed fuel gas can be specifically configured to be injected into the swirl premixed gas output channel (annular mixing section) along a tangential direction, and output toward the downstream in an axial spiral form within the annular mixing section, that is, the annular mixing section receives the swirl mixed gas and transforms it into a premixed fuel gas with axial spiral motion that is output toward the annular tapering section.

[0034] See also Figure 8 , Fig. 9 In this embodiment, the fuel gas premixing channel may specifically include a premixing air channel and a premixing fuel gas channel. The premixing air channel is formed by the interval between adjacent swirl blades 1-15 on the fuel nozzle body, and the premixing fuel gas channel is configured to extend inside the swirl blade and spray from the surface of the swirl blade 1-15, and output the low-reactivity fuel gas toward the premixing air channel. The swirl blade 1-15 is configured to guide the premixed air entering the premixing air channel to be premixed with the low-reactivity fuel gas to form a 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.

[0035] Specifically, the premixed air channel can be a number of tangential air channels 1-16 (circumferential spacing is achieved by swirl blades) opened in the fuel nozzle body along the circumferential interval. The tangential air channels 1-16 are axially discretely distributed on the fuel nozzle body. The airflow direction of the tangential air channels 1-16 is tangential to the annular mixing section. The tangential air channels 1-16 are used to guide the outer layer of air to enter the nozzle tangentially and disturb the flow field to form swirl air. The nozzle entity part between adjacent tangential air channels 1-16 is the asymmetric fan-shaped swirl blade 1-15. Among them, the swirl blade 1-15 can be a radial swirl blade or an axial swirl blade.

[0036] Furthermore, the premixed fuel gas channel includes a premixed fuel gas channel input section and a plurality of premixed fuel gas channel output sections which are connected in sequence.

[0037] If the output section of the premixed fuel gas channel can be specifically a premixed fuel gas channel axial delivery pipe 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 arranged at intervals along the axial direction. That is, the output section of the premixed fuel gas channel is opened in the swirl blade 1-15, and the premixed fuel gas channel injection holes 1-11 are also opened in the swirl blade 1-15, wherein the premixed fuel gas channel axial delivery pipe 1-10 can be connected to the 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 evenly distributed along the height direction of the swirl blade 1-15, so as to inject the fuel gas to the two tangential air channels 1-16 on both sides.

[0038] The input section of the premixed fuel gas channel may include a premixed fuel gas channel inlet pipe 1-7, an axial interlayer channel 1-8 of the premixed fuel gas channel, and a plurality of radial diffusion tubes 1-9 of the premixed fuel gas channel. The premixed fuel gas channel inlet pipe 1-7 may be radially arranged on the combustion nozzle body, and the axial interlayer channel 1-8 of the premixed fuel gas channel is an annular intermediate channel opened in the combustion nozzle body, one end of the annular intermediate channel is connected to the premixed fuel gas channel inlet pipe 1-7, and the other end is respectively connected to a plurality of radial diffusion tubes 1-9 of the premixed fuel gas channel extending radially in the combustion nozzle body, and the ends of the radial diffusion tubes 1-9 of the premixed fuel gas channel are respectively connected to the axial delivery pipes 1-10 of the premixed fuel gas channel.

[0039] In this embodiment, the fuel gas diffusion channel may specifically include a fuel gas diffusion channel input section, a plurality of fuel gas diffusion channel bending sections, and a fuel gas diffusion channel output section. The plurality of fuel gas diffusion channel bending sections are arranged at intervals in the circumferential direction, and the two ends of each fuel gas diffusion channel bending 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 tapered section, and the end of the fuel gas diffusion channel output section is connected to the annular tapered section through a plurality of fuel gas diffusion injection holes 1-6 arranged at intervals in the circumferential direction, that is, the fuel gas is ejected radially outward.

[0040] 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 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 which are connected in sequence, and 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 respectively, is transported radially outward to the fuel gas diffusion channel axial delivery pipe 1-3, is converted into axial transportation, and then enters the fuel gas diffusion channel radial return pipe 1-4, is transported radially inward, and 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 radially ejected outward through the fuel gas diffusion injection holes 1-6 thereon. Among them, the design of the return repetitive channel of the bending section device of the fuel gas diffusion channel is, on the one hand, for the needs of structural layout, and on the other hand, while achieving the purpose of inner layer diffusion fuel supply, through the bending transportation, the pressure gradient between the areas near the fuel gas diffusion injection holes 1-6 is reduced, thereby improving the uniformity of the incident fuel.

[0041] In this embodiment, the radial fast-mixing air channel includes a plurality of inner fast-mixing air input sections and inner fast-mixing air output sections. The inner fast-mixing air output section is located inside the output section of the fuel gas diffusion channel. The plurality of inner fast-mixing air input sections penetrate the fuel nozzle body and are connected to the inner fast-mixing air output section, and the plurality of inner fast-mixing air input sections are arranged alternately with the bent section of the fuel gas diffusion channel.

[0042] The inner fast-mix air input section can be specifically a fast-mix air radial delivery pipe 1-12, and the inner fast-mix air output section can be specifically a fast-mix air axial delivery pipe 1-13. The end of the fast-mix air axial delivery pipe 1-13 is provided with a plurality of radial fast-mix air channel injection ports 1-14 at intervals along the circumferential direction, and the radial fast-mix air channel injection ports 1-14 are axially located downstream of the annular tapered section. The fast-mix air radial delivery pipe 1-12 is arranged in the area corresponding to the above-mentioned fuel gas diffusion channel bending section and is misaligned therewith. External air enters the fast-mix air axial delivery pipe 1-13 radially from the fast-mix air radial delivery pipe 1-12 and converges, and then moves in the fast-mix air axial delivery pipe 1-13 and is transported to the radial fast-mix air channel injection ports 1-14 at the end, and is radially output outward from the radial fast-mix air channel injection ports 1-14. Among them, the radial fast mixing air channel injection port 1-14 is located downstream of the fuel gas diffusion injection hole 1-6, and can be set to be staggered in the circumferential direction along the swirl direction, that is, the injection direction of the radial fast mixing air channel injection port 1-14 is not tangent to the rotation direction of the spirally advancing fuel at the annular tapered section, so as to realize cross jets and make the mixing more uniform.

[0043] In this embodiment, for low-reactivity fuel gas represented by NH3 fuel, 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 mixed and tangentially injected into the annular mixing section. While completing the swirling of the flow field, the movement direction is changed from tangential to axial spiral rotation. Near the nozzle outlet, as the channel gradually shrinks, the mixed gas is accelerated, the turbulent kinetic energy increases, and the mixing becomes more uniform. Further downstream of the nozzle, on-duty diffusion combustion is organized (i.e., the fuel gas output through the fuel gas diffusion injection hole 1-6, where the fuel gas can be a low-reactivity fuel gas or a high-reactivity fuel gas), which plays an important supporting role in ignition start-up and stable combustion, but from the perspective of reducing NO x From 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.

[0044] For highly reactive fuel gases such as H2 fuel, in order to prevent nozzle flashback, the fuel can be set to enter only from the fuel gas diffusion channel.

[0045] 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.

[0046] Preferably, CH4 is used as the active comparison fuel. Fuels with higher activity than CH4 are considered to be high-reactivity fuel gases, and vice versa, low-reactivity fuel gases. The feed arrangement of common fuels is as follows:

[0047] The multi-fuel mixing nozzle for gas turbines of this embodiment is designed based on the combustion requirements of NH3, and can burn CH4, H2 and various synthetic gas fuels at the same time, greatly broadening the types of applicable fuels. In addition, the two cross-jet flows of axial swirl air and fuel, and radial fast-mixed air and upstream mixed air greatly promote the rapid and full mixing of fuels.

[0048] Embodiment 2 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.

[0049] 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.

[0050] The cap 4 is configured to gradually increase in axial diameter and form a small diameter end and a large diameter end in the axial direction (that is, the cap 4 is in a cone shape as a whole, and its cross-section is trapezoidal), 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.

[0051] Furthermore, the cap 4 includes an upstream wall 4-1 and a downstream wall 4-3 which are arranged in parallel and at intervals. The upstream wall 4-1 is connected to the fairing 3 and the flame tube 5 respectively, and the gap between the peripheral edge of the downstream wall 4-3 and the flame tube 5 is a cooling channel, wherein the upstream wall 4-1 is provided with a plurality of penetrating impingement cooling holes 4-2, and the air in the fairing 3 enters the flame tube 5 through the impingement cooling holes 4-2, the interval between the upstream wall 4-1 and the downstream wall 4-3, and the cooling channel.

[0052] That is, the cap 4 is set as a double-wall structure, which is gradually expanded 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 impact cooling hole 4-2, and then is output through the annular cooling channel between the flame tube 5 and the downstream wall 4-3. The swirling incoming air (mixed fuel gas) of the multi-fuel mixing nozzle 1 will form a recirculation vortex downstream, and a recirculation vortex (cooling air) with the opposite rotation direction will also be formed in the vicinity of the connection between the cap 4 and the flame tube 5, forming a recirculation zone at the shoulder of the combustion chamber, which promotes the circulation of smoke inside the combustion chamber and can achieve the dual effects of stable combustion and emission reduction.

[0053] Furthermore, an outer casing 2 may be sleeved on the outer side of the flame tube 5 and the fairing 3, and the interval between the outer casing 2 and the flame tube 5 and the fairing 3 is the air input channel. Mixing holes 5-1 connected to the air input channel may be provided on the flame tube 5, and the mixing holes 5-1 are arranged at intervals along the circumferential direction.

[0054] The combustion chamber of this embodiment can achieve a relatively low level of NO when burning hydrogen-rich fuels. xEmissions: Rapid and full mixing reduces the local high equivalence ratio and thus the maximum combustion temperature; at the same time, a nozzle with a gradually converging outlet is used in conjunction with a gradually expanding cap 4 to form a reflow zone at the shoulder of the combustion chamber, which promotes the circulation of smoke inside the combustion chamber and achieves the dual effects of stabilizing combustion and reducing emissions.

[0055] Embodiment 3 See also Figures 13 to 15 and Fig.17 This embodiment provides a multi-fuel combustion chamber based on the combustion of ammonia low-activity fuel, comprising a combustion chamber and the multi-fuel mixing nozzle for a gas turbine in the first embodiment, the multi-fuel mixing nozzle being installed in the combustion chamber. A combustion region extending along the axial direction is provided in the combustion chamber, and the combustion region comprises a rich combustion region, a reburning region and a burnout dilution region arranged in sequence along the axial direction.

[0056] The multi-fuel mixing nozzle is configured to output a rich mixed fuel gas of a rich fuel flow 7 and a rich air flow 8 toward the rich combustion area and / or to output a reburning mixed fuel gas of a reburning fuel flow 9 and a reburning air flow 10 toward the reburning area.

[0057] The fuel-rich air flow 8 accounts for 5% to 25% of the total air volume, the reburning air flow 10 accounts for 15% to 30% of the total air volume, and the burn-out dilution air flow 11 entering the burn-out dilution zone accounts for 45% to 80% of the total air volume.

[0058] Since the air entry ratio in various parts of the combustion chamber cannot be adjusted after the design is completed, only the fuel entry ratio in various parts of the combustion chamber can be adjusted. Therefore, this embodiment uses the design of a multi-fuel mixing nozzle to make the air entry ratio of the combustion chamber meet the combustion of ammonia low-activity fuel gas while also meeting the combustion of hydrogen high-activity fuel gas.

[0059] Under the combustion demand of ammonia low-activity fuel gas, the rich fuel flow 7 and the reburning fuel flow 9 are both ammonia low-activity fuel gas. The ratio of the two is set as follows: the rich fuel flow 7 accounts for 70% to 100% of the total amount of ammonia low-activity fuel gas, corresponding to the rich combustion state with a head equivalence ratio between 1 and 2, and the reburning fuel flow 9 accounts for 0% to 30% of the total amount of ammonia low-activity fuel gas. The ammonia low-activity fuel gas is set to enter the swirl premixed gas output channel through the fuel gas premixing channel and / or the fuel gas diffusion channel, and then the stable combustion of the ammonia low-activity fuel gas in the combustion chamber is achieved by premixing / or diffusion combustion.

[0060] Under the combustion demand of hydrogen-based high-activity fuel gas, both the rich fuel flow 7 and the reburning fuel flow 9 are hydrogen-based high-activity fuel gas. The ratio of the two is set as follows: the rich fuel flow 7 accounts for 5% to 25% of the total amount of hydrogen-based high-activity fuel gas, and the reburning fuel flow 9 accounts for 95% to 75% of the total amount of hydrogen-based high-activity fuel gas. The hydrogen-based high-activity fuel gas is set to enter the swirl premixed gas output channel through the fuel gas diffusion channel, and then the stable combustion of the hydrogen-based high-activity fuel gas in the combustion chamber is achieved by diffusion combustion.

[0061] Furthermore, after determining the distribution ratio of air and ammonia low-activity fuel in the rich combustion area, reburning area and burnout dilution area of ​​the combustion chamber based on the ammonia low-activity fuel, this embodiment can further introduce hydrogen-based 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-based low-activity 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.

[0062] Embodiment 4 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.

[0063] 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.

[0064] 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.

[0065] In this embodiment, the space in the combustion chamber is divided into a rich combustion area, a reburning area and a burnout dilution area which extend 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 the equivalence ratio in the rich combustion area where most of the NH3 fuel participates is controlled to be close to the high value of the flammable 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.

[0066] The specific structure of the combustion chamber of this embodiment is further described below: In this embodiment, the combustion chamber comprises a first combustion chamber section and an outlet contraction section which are arranged and connected along the axial direction. The rich combustion area and the reburning area are located in the first combustion chamber section, and the burnout dilution area is located in the outlet contraction section.

[0067] Specifically, the combustion chamber may be a flame tube 5, which is axially divided into a tube section with a larger diameter (corresponding to the above-mentioned first combustion chamber section) and a tube section with a smaller diameter (corresponding to the above-mentioned outlet contraction section).

[0068] In this embodiment, in the axial direction, the end face of the first combustion chamber section away from the burnout dilution region is the inlet end face. The rich fuel mixture is configured to be output to the rich fuel region through the inlet end face in the axial direction. The reburned mixture is configured to be output to the reburning region through the wall of the first combustion chamber section, and the output direction is perpendicular to the axial direction, or the reburned mixture is configured to be split and output to the reburning region through the wall of the first combustion chamber section, and the output direction is perpendicular to the axial direction. The burnout dilution air flow 11 is configured to be output to the burnout dilution region through the outlet contraction section.

[0069] The above-mentioned inlet end face can be a cover cap 4 installed on the flame tube 5. The above-mentioned rich fuel mixture enters the rich fuel area through the cover cap 4, and the reburning mixture enters the reburning area through the circumferential side wall of the flame tube 5.

[0070] In this embodiment, the combustion chamber may further include an outer casing 2 and a fairing component, and the fairing component may specifically be a fairing 3 .

[0071] The fairing 3 and the flame tube 5 are both arranged in the inner cavity of the outer casing 2, and the first end of the fairing 3 is connected to the end of the outer casing 2 close to the rich combustion area, and the second end of the fairing 3 is connected to the end of the flame tube 5 close to the rich combustion area (i.e., the end of the flame tube 5 equipped with the cap 4). In addition, the inner cavity wall of the outer casing 2 cooperates with the fairing component and the combustion chamber to form the above-mentioned air channel. The air channel surrounds the entire first combustion chamber section of the flame tube 5 and only part of the outlet contraction section, so that it is possible to open a hole on the outlet contraction section to introduce air into the burnout dilution area, and the air flow of this part can be specifically controlled by setting a flow valve or the like.

[0072] The inner cavity of the fairing 3 can cooperate with the combustion chamber end cover 6 of the outer casing 2 and the cap 4 to form a fuel-rich air input cavity connected to the above-mentioned air channel.

[0073] In this embodiment, the fuel gas premixing channel includes a rich fuel pipeline corresponding to the rich fuel flow 7 and at least one reburning fuel pipeline corresponding to the reburning fuel flow 9. The combustion chamber also includes a rich region nozzle 1A and at least one reburning region nozzle 1B (one-to-one correspondence with the reburning fuel pipeline). Among them, the rich region nozzle 1A and the reburning region nozzle 1B can both be the above-mentioned multi-fuel mixing nozzle 1.

[0074] The rich fuel area nozzle 1A can be arranged in the above-mentioned rich fuel air input chamber and connected to the cover cap 4, and the rich fuel area nozzle 1A is configured to receive a rich fuel flow 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 fuel air input chamber and is connected to the fuel input end of the rich fuel area nozzle 1A) and a rich fuel air flow 8 (the air input end of the rich fuel area nozzle 1A can be directly connected to the rich fuel air input chamber) for swirl premixing to form a rich fuel mixture, and is ejected to the rich fuel area through the opening of the rich fuel area nozzle 1A on the second side of the cover cap 4, and the output direction is along the axis of the flame tube 5.

[0075] The reburning zone nozzle 1B can be configured to be arranged around the output path of the fuel-rich mixture and connected to the combustion chamber (i.e., installed on the circumferential side wall of the flame tube 5 in a circumferential manner). The reburning zone nozzle 1B is configured to receive the reburning fuel flow 9 (the above-mentioned reburning fuel pipeline passes through the outer casing 2 and extends into the air channel and is connected 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 channel) for swirl premixing to form a reburning mixture, and output it to the reburning area, and the output direction can be perpendicular to the axis of the flame tube 5. The number of the above-mentioned reburning zone nozzles 1B can be 4 to 8, specifically 6, and they are evenly arranged in the circumferential direction.

[0076] Furthermore, at least one mixing hole 5-1 arranged around the output path of the fuel-rich mixture may be provided on the outlet contraction section of the flame tube 5, and the burnout dilution air flow 11 (i.e., the airflow entering the through hole in the air passage) is output to the burnout dilution area through the mixing hole 5-1, and the output direction may be perpendicular to the axis of the flame tube 5. The number of the mixing holes 5-1 may be 4 to 8, and they are evenly arranged in the circumferential direction.

[0077] Based on this, the combustion chamber of this embodiment achieves the following beneficial effects: 1. Easy to start: The rich combustion area of ​​the head adopts a swirl burner (multi-fuel mixing nozzle 1), forming a reflow zone downstream, which is conducive to ignition and stable fire. By reasonably setting the fuel amount under ignition conditions, the equivalence ratio near the head igniter is distributed in a stable combustible range, so that the gas turbine can be ignited and started at room temperature, simplifying the ignition and starting system without increasing other types of exhaust emission sources.

[0078] 2. Improve combustion stability: Through the multi-stage arrangement of fuel and air, a rich fuel area, a reburning area and a burnout dilution area are formed in the combustion chamber. The local equivalence ratio of each area has a large span, especially the equivalence ratio of the rich fuel area has a large downward space within the stable combustion range. The change range of the local equivalence ratio when increasing the speed and load can be limited to the combustible range, thereby achieving the effect of stable combustion throughout the process.

[0079] In summary, compared with the prior art, this technical solution forms a fuel-rich area, a reburning area and a burnout dilution area in the combustion chamber through a multi-stage arrangement of fuel and air, and reasonably sets the equivalence ratio of each area, which can achieve ignition and start-up at room temperature, improve combustion stability and combustion efficiency, and reduce nitrogen oxide emissions, thereby achieving stable, efficient and clean combustion of NH3 in gas turbines, and promoting large-scale application of ammonia in the field of gas turbines.

[0080] Embodiment 5 refer to Fig.16 In this embodiment, the arrangement of the combustion chamber is adjusted on the basis of the above-mentioned embodiment 4, as follows: The combustion chamber includes a second combustion chamber section, a third combustion chamber section and an outlet contraction section which are arranged and connected in the axial direction, 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 fuel area is located in the second combustion chamber section, and the reburning area and the burnout dilution area are located in the third combustion chamber section.

[0081] In the axial direction, the end face of the second combustion chamber segment away from the burnout dilution region is the inlet end face, and the end face of the third combustion chamber segment away from the burnout dilution region cooperates with the second combustion chamber segment to form a step end face.

[0082] The rich fuel mixture is configured to be output to the rich fuel region through the inlet end face in the axial direction. The reburned fuel mixture is configured to enter the reburned region through the step end face in the axial direction, or the reburned fuel mixture is configured to be split and respectively enter the reburned region through the step end face in the axial direction. The burnout dilution air flow 11 is configured to be output to the burnout dilution region through the wall 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 respectively output to the burnout dilution region through the wall of the third combustion chamber section, and the output direction is perpendicular to the axial direction.

[0083] Specifically, the combustion chamber can be a flame tube 5, which includes three sections of the cylinder, and the diameters of the first section and the third section are smaller than the second section in the middle; wherein, no transition section is provided between the first section and the second section, and the above-mentioned step end face can be formed, and the step end face can be an annular cover cap 4B, and a transition section can be provided between the second section and the third section.

[0084] The fairing 3 can be configured to be directly connected to the step end face of the second section of the cylinder, so that the space between the step end face and the first section of the cylinder is also located in the above-mentioned rich air input chamber (essentially a chamber shared by rich air and reburning air); the above-mentioned rich area nozzle 1A can still be arranged on the central cover cap 4A of the first section of the cylinder, and the rest of the arrangement is similar to that of Example 4; the above-mentioned reburning area nozzle 1B can be arranged on the annular cover cap 4B, and the above-mentioned 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) for swirl premixing to form a reburning mixture, and output it to the reburning area, and the output direction can be parallel to the axis of the flame tube 5.

[0085] In this arrangement, the partially burned-out dilution area can be moved forward to the second section of the cylinder, so the mixing hole 5-1 can be arranged at the end of the second section of the cylinder.

[0086] In terms of structure, the fuel-rich area and the reburning area are arranged in two levels in a radial stepped manner, so as to achieve relative isolation and independence in physical space and reduce the mutual influence between the two areas.

[0087] Embodiment 6 This embodiment provides a combustion method based on the above embodiment. The combustion method can be applied to a combustion chamber having a multi-fuel mixing nozzle for a gas turbine according to the above embodiment 1, and can also be applied to the combustion chambers in the above embodiments 2 to 5. The method is as follows: A rich combustion area, a reburning area and a burnout dilution area are arranged in sequence along the axial direction in the combustion chamber. A rich combustion mixture formed by a rich combustion fuel flow 7 and a rich combustion air flow 8 is input to the rich combustion area, a reburning mixture formed by a reburning fuel flow 9 and a reburning air flow 10 is input to the reburning area, and a burnout dilution air flow 11 is input to the burnout dilution area; Among them, the fuel amount of the rich fuel flow 7 accounts for 70% to 100% of the sum of the fuel amounts of the rich fuel flow 7 and the reburning fuel flow 9; the sum of the air amounts of the rich air flow 8, the reburning air flow 10 and the burnout dilution air flow 11 is the total air amount, the air amount of the rich air flow 8 accounts for 5% to 25% of the total air amount, and the air amount of the reburning air flow 10 accounts for 15% to 30% of the total air amount.

[0088] The combustion method of this embodiment takes NH3 fuel as the starting point and can burn H2, CH4 and other synthesis gases.

[0089] The technical principle of the combustion chamber of this embodiment is further explained below: See also Fig.14 The entire combustion chamber is divided into a rich combustion area, a reburning area and a burnout dilution area, and carries different functional positioning.

[0090] The head fuel-rich area adopts a multi-fuel mixing nozzle 1 to form a reflow area downstream, which is conducive to ignition and stable fire. By reasonably setting the fuel amount under ignition conditions, the equivalence ratio near the head igniter is distributed in a stable combustible range, so that the gas turbine can be ignited and started at room temperature, simplifying the ignition and starting system without adding other types of exhaust emission sources. In addition, in the fuel-rich area, in order to suppress the emission of nitrogen oxides and maintain stable combustion under variable load conditions, the equivalence ratio of this area is set to a value close to the high combustible limit. To this end, 5% to 25% of the air volume and 70% to 100% of the fuel volume are arranged in the fuel-rich area. Fig.13 It can be seen that in the atmospheric premixed combustion of ammonia, as the equivalence ratio increases, NO x It shows a trend of first increasing and then decreasing, with the peak appearing near the equivalence ratio of 0.9. In the area above the equivalence ratio of 1.2, nitrogen oxide emissions tend to 0 ppm, thus achieving the goal of reducing emissions.

[0091] When the air volume does not change much during the process of gas turbine load increase or decrease, the fuel volume changes in a wide range. For example, the equivalence ratio of the entire combustion chamber will increase exponentially during the stage from full speed no-load to full load. For this reason, the equivalence ratio of the rich combustion area at full load is set at a high value close to the flammable limit. In this way, when the load changes, especially when the load decreases, the equivalence ratio of the rich combustion area has a large downward space within the stable combustion range, and the range of the equivalence ratio of the rich combustion area can be limited to the combustible area, thereby achieving the effect of stable combustion throughout the process.

[0092] In the reburning area, the main task is to quickly consume NH3 and release the heat of the fuel. The equivalence ratio after the reburning area is set to a value close to the low flammable limit. Fig.13 As shown in the figure, in the atmospheric premixed combustion of ammonia, the residual NH3 at the outlet increases with the increase of the equivalence ratio. It is foreseeable that since the equivalence ratio in the rich combustion area is set to a high value close to the flammability limit, the unburned NH3 will escape from the rich combustion area. For this reason, 15-30% air and 0-30% NH3 are arranged in the downstream reburning area, so that the local equivalence ratio before and after the reburning area varies from a high value of rich combustion to a low value of lean combustion, but the equivalence ratio in the reburning area is generally in a stable combustion area, so that the NH3 fuel is consumed rapidly.

[0093] 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 the mutual influence between the two zones.

[0094] Finally, after entering the burnout dilution zone, with the addition of 45~80% air, the unburned NH3 is further burned, 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.

[0095] Based on this, the combustion method of this embodiment achieves the following beneficial effects: 1. Low NOx emissions: Fig.13 As shown in the figure, in the atmospheric premixed combustion of ammonia, as the equivalence ratio increases, NO x It shows a trend of increasing first and then decreasing, with the peak value appearing near the equivalence ratio of 0.9, and in the range above equivalence ratio of 1.2, nitrogen oxide emissions tend to 0. After the multi-stage arrangement of air and fuel, the air volume in the rich combustion area accounts for 5% to 25%, and the fuel volume accounts for 70% to 100%, so that the equivalence ratio in the rich combustion area where most of the NH3 fuel is involved is controlled close to the high value of the flammable limit, making NO x Emissions are greatly reduced. Downstream, with the relay addition of 15-30% air and 0-30% fuel, the equivalence ratio in the reburning zone is controlled near the low value close to the flammable limit, and also deviates from the peak equivalence ratio of nitrogen oxides near 0.9, thereby effectively controlling the cumulative nitrogen oxide emissions at the outlet, keeping the emissions within an acceptable low range.

[0096] 2. Improve combustion efficiency: To reduce NO x In the rich fuel region, the equivalence ratio is controlled at a high value close to the flammable limit, while the outlet residual NH3 increases with the increase of the equivalence ratio. Figure 1As shown. It is foreseeable that unburned NH3 will escape from the rich combustion area. To this end, 15-30% air and 0-30% NH3 are arranged in the reburning area, so that the local equivalence ratio before and after the reburning area varies from a high value of rich combustion to a low value of lean combustion, but the equivalence ratio in the reburning area is generally in a stable combustion range, thereby rapidly consuming NH3 fuel. After entering the burnout dilution area, with the addition of 45-80% air, the unburned NH3 is further burned, the combustion efficiency is improved, and the rapid dilution achieves the purpose of cooling, freezing the formation of nitrogen oxides.

[0097] The embodiments of the present invention are described in detail above in conjunction with 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 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 passage is located downstream of the output end of the fuel gas diffusion passage, and the radial fast-mixing air passage is configured to output radial fast-mixing air to the swirl premixed gas output passage.

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 fuel gas premixing channel includes a premixing fuel gas channel and a premixing air channel; The intervals between adjacent swirl blades on the fuel nozzle body form the premixed air channel, and the premixed fuel gas channel is configured to extend within the swirl blades and spray from the surfaces of the swirl blades to output low-reactivity characteristic fuel gas toward the premixed air channel; the swirl blades are configured to guide the premixed air entering the premixed 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.

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

5. The multi-fuel mixing nozzle for a gas turbine according to claim 1, characterized in that: 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.

6. 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.

7. 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.

8. A multi-fuel combustion chamber based on the combustion of ammonia low-activity 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 7 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.

9. The multi-fuel combustion chamber based on combustion of ammonia-based low-activity fuel according to claim 8, characterized in that: The rich fuel flow and the reburn fuel flow are ammonia low-activity fuel gas, the rich fuel flow accounts for 70% to 100% of the total amount of the ammonia low-activity fuel gas, corresponding to the rich state with a head equivalence ratio between 1 and 2, and the reburn fuel flow accounts for 0% to 30% of the total amount of the ammonia low-activity fuel gas; The ammonia 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 combustion of ammonia-based low-activity fuel according to claim 8, 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.

11. The multi-fuel combustion chamber based on combustion of ammonia-based low-activity fuel according to claim 8 or 9, characterized in that: After determining the distribution ratio of air and ammonia low-activity fuel gas in the rich combustion area, reburning area and burnout dilution area of ​​the combustion chamber based on ammonia low-activity 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.

12. 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 7; 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 a 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.

13. The combustion chamber according to claim 12, 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.

14. The combustion chamber according to 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: Applied to a combustion chamber comprising a multi-fuel mixing nozzle for a gas turbine as claimed in any one of claims 1 to 7, or applied to a combustion chamber as claimed in any one of claims 8 to 14, 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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