Heavy-duty gas turbine combustor and wide load low emissions control method

Abstract

The application discloses a heavy-duty gas turbine combustor and a wide-load low-pollution control method thereof. The heavy-duty gas turbine combustor comprises a combustor head, the combustor head comprises an end cover, a cover cap installed downstream of the end cover and a fairing arranged between the cover cap and the end cover, a plurality of nozzles are installed on the end cover and arranged in an internal passage of the cover cap, the plurality of nozzles comprise a central nozzle arranged at a radial center and a plurality of peripheral nozzles arranged in a ring array around the central nozzle, a flow area of the central nozzle is greater than that of any peripheral nozzle, at least two adjacent peripheral nozzles are configured to have opposite swirl directions, and a duty nozzle is arranged in each nozzle. The combustor with the specific nozzle layout and the integrated duty nozzle structure is combined with a dynamic fuel staging control strategy of the gas turbine in a whole operation cycle, so that smooth transition and optimized operation from ignition, speed-up, low load to high load are realized.

Description

Technical Field

[0001] This invention relates to the field of low-pollution combustion technology for gas turbines, and more particularly to a heavy-duty gas turbine combustor and its wide-load low-pollution control method. Background Technology

[0002] As a large-scale, highly efficient and clean power plant, the performance of the combustion chamber in a heavy-duty gas turbine directly affects the unit's efficiency, emissions, and operational reliability. With increasingly stringent environmental requirements, dry, low-emission combustion technology has become mainstream. However, heavy-duty gas turbine combustion chambers, particularly those employing a combined premixing and standby nozzle design, exhibit significant shortcomings when operating across a wide load range. For example, during rapid load changes, fuel-air mixing control struggles to respond promptly, leading to unstable or incomplete combustion and potentially inducing combustion oscillations. Simultaneously, balancing flame stability and pollutant control is difficult under both low and high load conditions; low loads result in easy flameout and high CO emissions, while high loads exacerbate NOx emissions and increase the risk of thermoacoustic oscillations. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] To this end, embodiments of the present invention propose a heavy-duty gas turbine combustor and its wide-load low-pollution control method. Through a combustor with a specific nozzle layout and an integrated duty nozzle structure, combined with a dynamic fuel grading control strategy for the entire operating cycle of the gas turbine, a smooth transition and optimized operation from ignition, acceleration, low load to high load can be achieved.

[0005] The heavy-duty gas turbine combustion chamber of this invention includes:

[0006] The combustion chamber head includes an end cap, a hood installed downstream of the end cap, and a fairing disposed between the hood and the end cap. Multiple nozzles are mounted on the end cap and pass through an internal channel provided by the cap. The multiple nozzles include a central nozzle located at the radial center and multiple peripheral nozzles arranged in a ring array around the central nozzle. The flow area of ​​the central nozzle is larger than the flow area of ​​any of the peripheral nozzles. At least two adjacent peripheral nozzles are configured to have opposite swirl directions. Each nozzle has a standby nozzle, which includes a fuel injection orifice located at the end of the nozzle.

[0007] In some embodiments, the ratio of the flow area of ​​the peripheral nozzle to the flow area of ​​the central nozzle is 0.6 to 0.8.

[0008] In some embodiments, the fairing is provided with a plurality of rectifier holes and at least one guide plate, the guide plate being located downstream of the rectifier holes, the guide plate being used to distribute airflow to the central nozzle and the peripheral nozzle.

[0009] In some embodiments, each of the duty nozzles further includes a purge air system in communication with the fuel passage of the duty nozzle, the purge air system being configured to introduce purge air into the fuel passage after the fuel supply to the corresponding duty nozzle is cut off.

[0010] In some embodiments, each of the duty nozzles is further provided with at least one cooling hole at its end, the cooling hole being connected to a cleaning air passage or a cooling air source.

[0011] In some embodiments, the diameter of the cooling hole is 1 mm to 2.5 mm, and the amount of cooling air supplied by the cooling hole accounts for 0.1% to 0.5% of the total air flow in the combustion chamber.

[0012] In some embodiments, the peripheral nozzles are divided into at least two groups according to the swirling direction, with the peripheral nozzles in each group having the same swirling direction and the swirling directions between different groups being opposite.

[0013] The wide-load, low-pollution control method for the heavy-duty gas turbine combustor described in any of the above embodiments of the present invention includes: During the ignition phase of the heavy-duty gas turbine, fuel is supplied to the duty nozzles in the central nozzle and the peripheral nozzles. The fuel quantity supplied to the central duty nozzle accounts for 2% to 15% of the total fuel quantity, and the fuel quantity supplied to the peripheral duty nozzle accounts for 2% to 10% of the total fuel quantity. During the speed increase and low load operation phases of heavy-duty gas turbines, the fuel supply ratio between the central duty nozzle and the peripheral duty nozzles should be adjusted so that the fuel quantity of the central duty nozzle is maintained at 1% to 5% and the fuel quantity of the peripheral duty nozzle is maintained at 1% to 6%. During the high-load operation phase of heavy-duty gas turbines, the fuel supply ratio between the central duty nozzle and the peripheral duty nozzles is reduced, so that the fuel quantity of the central duty nozzle is reduced to 0% to 2% and the fuel quantity of the peripheral duty nozzle is reduced to 0% to 3%.

[0014] In some embodiments, the fuel flow rates of the central duty nozzle and the peripheral duty nozzle are adjusted in a closed loop based on the real-time load signal and combustion chamber pressure pulsation signal of the heavy-duty gas turbine.

[0015] In some embodiments, when the fuel supply to any duty nozzle is cut off, the corresponding purging air system is activated, wherein the response time of the purging valve in the purging air system is less than 1.2 seconds, and the purging air flow rate is maintained between 10 m / s and 60 m / s until the fuel residual volume concentration in the fuel passage of the duty nozzle is less than 0.1%.

[0016] In summary, in the embodiments of this invention, a differentiated nozzle layout with a center-periphery configuration and an alternating swirl design, combined with independently integrated standby nozzles for each nozzle, enables the combustion chamber to possess rapid mixing response and precise control capabilities. Based on this, a dynamic fuel grading control strategy that runs through the entire combustion chamber operating condition ensures flame stability and low CO emissions at low loads by utilizing the fuel-rich core of the standby nozzles. At high loads, this is transformed into an active adjustment unit to suppress thermoacoustic oscillations and control NOx emissions. This resolves the coupling contradiction between low-load flameout and high-load low-pollution / oscillation suppression within a wide load range, achieving a smooth transition and synergistic optimization from ignition and acceleration to full load, thus improving the stability, environmental friendliness, and reliability of heavy-duty gas turbines under complex operating conditions. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the combustion chamber of a heavy-duty gas turbine according to an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the combustion chamber head according to an embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of a cap according to an embodiment of the present invention.

[0020] Figure 4 This is a schematic diagram of the central nozzle flow channel and the peripheral nozzle flow channel according to an embodiment of the present invention.

[0021] Figure 5 This is a schematic diagram of the shearing action when adjacent peripheral nozzles rotate in the same direction according to an embodiment of the present invention.

[0022] Figure 6 This is a schematic diagram illustrating the shearing action when adjacent peripheral nozzles rotate in different directions according to an embodiment of the present invention.

[0023] Figure 7 This is a schematic diagram of the shearing action of the central nozzle and the peripheral nozzle in an embodiment of the present invention.

[0024] Figure 8 This is a schematic diagram of the central duty nozzle according to an embodiment of the present invention.

[0025] Figure 9 This is a schematic diagram of the peripheral duty nozzle in an embodiment of the present invention.

[0026] Figure 10This is a schematic diagram of the fairing according to an embodiment of the present invention.

[0027] Figure label: 1-Combustion chamber; 2- Combustion chamber head; 21-Center nozzle; 211-Center duty nozzle; 212-Center duty cooling hole; 213-Center duty fuel injection hole; 214-Center duty fuel passage; 22-Outer nozzle; 221-Outer duty nozzle; 222-Outer duty cooling hole; 223-Outer duty fuel injection hole; 224-Outer duty fuel passage; 23-End cap; 24-Fairing; 241-Fairing orifice; 242-Guide plate; 243-Fairing mounting block; 25- Casing: 26 - Cap; 261 - Center nozzle channel; 262 - Peripheral nozzle channel; 3-Flow guide bushing; 4-Flame tube; 5-Transition section. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0029] The following describes, with reference to the accompanying drawings, an embodiment of the present invention: a heavy-duty gas turbine combustion chamber and its wide-load, low-pollution control method.

[0030] like Figure 1 As shown, the heavy-duty gas turbine combustion chamber 1 of this embodiment of the invention adopts a counter-flow annular tube design. The combustion chamber 1 includes a combustion chamber head 2, a flow guide bushing 3, a flame tube 4, and a transition section 5.

[0031] like Figures 2 to 4 As shown, the combustion chamber head 2 includes an end cap 23, a fairing 24, a casing 25, a shroud 26, and multiple nozzles. The end cap 23 forms the upstream boundary of the combustion chamber head 2, and a fuel passage is arranged inside the end cap 23. The shroud 26 is installed downstream of the end cap 23, and the outer wall of the shroud 26 forms the upstream inlet boundary of an annular air passage with the inner wall of the casing 25. The shroud 26 has multiple independent internal passages, and their number and position correspond to the nozzles.

[0032] Multiple nozzles are mounted on the end cap 23 and each passes through a corresponding internal channel on the cap 26, thus being fixed to the cap 26 and forming independent flow channels. The nozzles employ a coordinated central and peripheral design, with a central nozzle 21 positioned at the radial center and multiple peripheral nozzles 22 arranged in a ring array around the central nozzle 21. Preferably, there are six or nine peripheral nozzles 22, evenly distributed circumferentially. The internal channel of the cap 26 corresponding to the central nozzle 21 is called the central nozzle channel 261, and the internal channel of the cap 26 corresponding to the peripheral nozzles 22 is called the peripheral nozzle channel 262.

[0033] The flow area of ​​the central nozzle 21 is designed to be larger than that of any of the peripheral nozzles 22. Specifically, the ratio of the flow area of ​​the peripheral nozzles 22 to that of the central nozzle 21 is preferably between 0.6 and 0.8, so that the central nozzle 21 can independently undertake the main combustion task under low load conditions, and can also form a larger stable core combustion zone under high load conditions, which helps to suppress the thermoacoustic oscillations caused by flame coupling of the peripheral nozzles 22.

[0034] like Figures 5 to 7 As shown, the swirl directions of each peripheral nozzle 22 are configured differently. Preferably, adjacent peripheral nozzles 22 adopt alternating clockwise and counterclockwise swirl directions, thereby forming a strong shear layer at the interface between nozzles, inducing high-intensity turbulent pulsations, accelerating fuel-air mixing, and breaking the symmetrical flow field, avoiding fuel enrichment concentration, and reducing local high-temperature hotspots and pollutant generation. Furthermore, the difference in the swirl directions of the peripheral nozzles 22 can also expand the recirculation zone or form a multi-stage recirculation structure, enhancing flame stability by adjusting the interaction between flames. The swirl direction of the central nozzle 21 can be selected to form a strong reverse swirl with some or all of the peripheral nozzles to further disrupt high-frequency standing wave formation and suppress high-frequency pulsations.

[0035] like Figure 8 and Figure 9 As shown, each nozzle (including the central nozzle 21 and each peripheral nozzle 22) has a standby nozzle integrated inside. The standby nozzle corresponding to the central nozzle 21 is the central standby nozzle 211, and the standby nozzle corresponding to the peripheral nozzle 22 is the peripheral standby nozzle 221.

[0036] The center nozzle 211 is embedded at the center of the end of the center nozzle 21. The center nozzle 211 mainly includes a center fuel injection hole 213 and a center fuel passage 214. The peripheral nozzle 221 is embedded at the center of the end of the peripheral nozzle 22. The peripheral nozzle 221 mainly includes a peripheral fuel injection hole 223 and a peripheral fuel passage 224.

[0037] The fuel quantity of the central duty nozzle 211 can range from 0% to 15% of the total fuel quantity under different load conditions, while the fuel quantity of the peripheral duty nozzle 221 can range from 0% to 10% of the total fuel quantity under different load conditions. Thus, the duty nozzles can provide flexible flame stabilization capabilities for stable operation under a wide range of operating conditions and low pollution emissions.

[0038] Therefore, in the heavy-duty gas turbine combustion chamber 1 of the present invention, the central nozzle 21 can work independently under low load conditions, carrying all the energy for the gas turbine to accelerate; it can also form a large stable combustion zone under high load conditions, suppressing the thermoacoustic coupled flame pattern formed by the flame coupling of the peripheral nozzles.

[0039] The outer nozzle 22 employs alternating swirling directions. These different swirling directions create a strong shear layer at the nozzle interface, inducing high-intensity turbulent pulsations. The generation and breakup of vortices in the shear zone significantly enhance the momentum and mass exchange rate, accelerating air-fuel mixing. Compared to nozzles with identical swirling directions, alternating swirling can disrupt the symmetrical flow field, preventing fuel enrichment and reducing combustion hotspots or contaminant formation caused by excessively high local stoichiometric ratios. The difference in swirling directions can also expand the recirculation zone or form a multi-stage recirculation structure, enhancing flame stability by adjusting inter-flame interactions.

[0040] Each nozzle integrates an independent duty nozzle, thus providing each combustion unit with an independent and rapid flame stabilization and adjustment "anchor point," enabling dynamic fuel control to penetrate into every local flame, achieving precise control under all operating conditions, and improving the combustion chamber's adaptability to operating conditions, mixing response speed, and control flexibility.

[0041] In some embodiments, each duty nozzle further includes a purge air system in communication with the fuel passage of the duty nozzle, the purge air system being configured to introduce purge air into the fuel passage after the fuel supply to the corresponding duty nozzle is cut off.

[0042] Understandably, for safety reasons, each duty nozzle's upstream fuel line is designed with an independent purging air system (not shown in the diagram). The purging air system must be activated immediately after fuel supply to that duty nozzle is cut off. The response time of the purging valve should be less than 1.2 seconds. The purging speed of the purging air system should be between 10-60 m / s (central duty) or 15-60 m / s (peripheral duty). Purging must be continuous to ensure that the residual fuel concentration in the fuel passage is below 0.1% by volume, thus completely eliminating the risk of spontaneous combustion.

[0043] Furthermore, such as Figure 8 and Figure 9 As shown, each duty nozzle is also provided with at least one cooling hole at its end, which is connected to the cleaning air channel or cooling air source.

[0044] Since the tip of the duty nozzle may be close to the flame front, especially under high load, a cooling function needs to be integrated. Therefore, a cooling channel and multiple cooling holes (e.g., 3-6) are designed at the tip of each duty nozzle. The cooling hole of the center duty nozzle 211 corresponds to the center duty cooling hole 212, and the cooling hole of the outer duty nozzle 221 corresponds to the outer duty cooling hole 222.

[0045] The diameter of the central cooling hole 212 and the peripheral cooling holes 222 is preferably 1-2.5 mm. Cooling air can be introduced from the cleaning channel or supplied by an independent source. The air is sprayed to form a protective air film, which can reduce the local temperature at the nozzle tip by about 100°C and keep the wall temperature below 850°C. The cooling holes account for about 0.1%-0.5% of the total airflow.

[0046] In some embodiments, such as Figure 2 and Figure 10 As shown, the fairing 24 is provided with a plurality of rectifier holes 241 and at least one guide plate 242. The guide plate 242 is located downstream of the rectifier holes 241 and is used to distribute the airflow to the central nozzle 21 and the peripheral nozzle 22.

[0047] That is, an integral shroud 24 is arranged upstream of the nozzle and the cap 26. The shroud 24 is fixedly assembled by the shroud mounting block 243. The shroud 24 is used to rectify the air entering multiple nozzles to ensure airflow uniformity. The shroud 24 is provided with multiple rectification holes 241. After the airflow passes through the multiple rectification holes 241, it is rectified and the turbulence is increased. The shroud 24 is also provided with a guide plate 242 that cooperates with the rectification holes 241. The guide plate 242 is used to control the flow velocity entering the premixing channel of each nozzle to be as uniform as possible.

[0048] The axial position of the deflector 242 is approximately half the length of the fairing 24. The position, height, and length of the deflector 242 can be dynamically adjusted according to actual flow distribution requirements, with the height-to-length ratio between 0.7 and 1.1. Its main function is to distribute the airflow entering the combustion chamber head 2 to the central nozzle 21 and the peripheral nozzles 22 according to a predetermined ratio. The number of deflectors 242 can be single (corresponding to the entire head) or multiple (corresponding to the upstream of each nozzle).

[0049] In some embodiments, the combustion chamber 1 also includes a highly efficient flame tube cooling technology. The flame tube 4 is cooled using a combination of impact cooling and finned cooling. By arranging multiple rows of impact cooling holes in the rear half of the guide bushing 3, the rear half of the flame tube 4 is subjected to impact cooling. The number of rows of impact holes is between 5 and 8, the number of impact cooling holes in each row is between 30 and 40, and the hole diameter is between 15 mm and 35 mm. The impact holes at different positions can be selected with different design schemes, such as equal diameter or variable diameter. The heat transfer coefficient is between 2000 W / m2·K and 3700 W / m2·K.

[0050] By arranging multiple rows of fins in the front half of the flame tube 4, the front half of the flame tube 4 is cooled by fins. The number of fin rows is 25-35, the fin spacing is 6-10mm, the fin height is 1-2mm, and the heat transfer coefficient is between 2000W / m2·K and 3000W / m2·K.

[0051] The guide bushing 3 is connected to the casing 25 via an expansion section structure. The design of the expansion section ensures that the velocity in the guide bushing 3 channel is sufficiently high to enhance convective heat transfer, while simultaneously slowing the airflow as it passes through the expansion section, allowing the flow to fully develop before entering the fairing 24. The expansion ratio (the ratio of the outlet cross-sectional area A_out to the inlet cross-sectional area A_in) is preferably 1.5 ≤ A_out / A_in ≤ 2.5, and the ratio of the expansion section length to the outlet height of the guide bushing 3 is between 1 and 2.

[0052] Both the central nozzle 21 and the peripheral nozzle 22 employ a multi-section control design for their swirl blades, which are radially divided into at least three independent control sections (e.g., blade root, blade middle, and blade tip), each with differentiated blade profile parameters. This design aims to increase the turbulence intensity at the swirl blade outlet to over 13% and reduce the mixing non-uniformity at the nozzle tip to below 5% (center) or 10% (peripheral). Under lean combustion conditions with an equivalence ratio of 0.5 and an outlet temperature of 1450℃, the target is to achieve NOx emissions ≤15ppm@15%O2, CO emissions ≤2ppm@15%O2, and combustion efficiency ≥99.99%.

[0053] The flow velocity entering each nozzle premixing channel is generally controlled between 45 m / s and 65 m / s. Within this velocity range, the shedding of low-velocity vortices can be avoided, while preventing flow separation caused by high-velocity airflow, thus eliminating high-frequency pulsation at its source.

[0054] In some embodiments, the peripheral nozzles 22 are divided into at least two groups according to the swirl direction. The peripheral nozzles 22 within each group have the same swirl direction, while the swirl directions between different groups are opposite. For example, among six peripheral nozzles, three with clockwise swirl are grouped as group A, and three with counterclockwise swirl are grouped as group B. The peripheral nozzles 22 within each group have the same swirl direction, but the swirl directions between group A and group B are opposite. The peripheral standby nozzles 221 can be controlled hierarchically according to this grouping method, with each level controlled separately in the gas turbine, rather than being controlled as a single unit.

[0055] By grouping the peripheral nozzles 22 according to the swirl direction and independently controlling their fuel supply (including main fuel and standby fuel), the combustion intensity and heat release distribution between regions with different swirl directions can be actively adjusted. For example, the fuel distribution between two groups can be slightly adjusted to optimize the circumferential temperature distribution or to specifically suppress oscillations associated with specific swirl patterns. This further improves the controllability and performance ceiling of the alternating swirl design, allowing the flow field and combustion process in the combustion chamber to be dynamically and precisely shaped not only through structural design but also through control strategies, with greater potential for achieving lower emissions and stronger oscillation suppression.

[0056] The wide-load, low-pollution control method for the combustion chamber of a heavy-duty gas turbine in the above embodiments of the present invention includes: During the ignition phase of the heavy-duty gas turbine, fuel is supplied to the duty nozzles inside the central nozzle 21 and the duty nozzles inside the peripheral nozzles 22. The fuel quantity of the central duty nozzle 211 accounts for 2% to 15% of the total fuel quantity, and the fuel quantity of the peripheral duty nozzles 221 accounts for 2% to 10% of the total fuel quantity. During the speed increase and low load operation phases of heavy-duty gas turbines, the fuel supply ratio between the central duty nozzle 211 and the peripheral duty nozzle 221 is adjusted so that the fuel quantity ratio of the central duty nozzle 211 is maintained at 1% to 5%, and the fuel quantity ratio of the peripheral duty nozzle 221 is maintained at 1% to 6%. During the high-load operation phase of the heavy-duty gas turbine, the fuel supply ratio of the central duty nozzle 211 and the peripheral duty nozzle 221 is reduced, so that the fuel quantity of the central duty nozzle 211 is reduced to 0% to 2% and the fuel quantity of the peripheral duty nozzle 221 is reduced to 0% to 3%.

[0057] Specifically, the core of the wide-load, low-pollution control method in this invention is a staged fuel supply and dynamic nozzle combination control strategy. Through the coordinated regulation of premixed nozzles and standby nozzles, smooth transitions and optimizations of the combustion mode are achieved across the entire operating range. This control strategy operates throughout the entire gas turbine operating cycle. Ignition stage: To achieve reliable ignition over a wide range, the proportion of fuel in the central duty nozzle 211 to the total fuel is controlled within the range of 2%-15%, and the proportion of fuel in the peripheral duty nozzle 221 to the total fuel is controlled within the range of 2%-10%.

[0058] During the speed increase phase: As the gas turbine speed gradually increases, in order to ensure flame stability and smooth combustion transition, the fuel quantity ratio of the central duty nozzle 211 is adjusted to the range of 2%-5%, and the fuel quantity ratio of the peripheral duty nozzle 221 is adjusted to the range of 2%-5%.

[0059] Low-load combustion mode switching phase: To ensure a smooth transition between combustion modes during load increases, the fuel percentage of the central control nozzle 211 is further adjusted to within the range of 1%-3%, and the fuel percentage of the peripheral control nozzle 221 is adjusted to within the range of 1%-6%. During this phase, the control nozzles provide a longer flame, forming a continuous fuel-rich core (equivalent ratio Φ=1.2-1.5), with a core flame temperature reaching 1700℃–1900℃. This not only maintains strong flame stability and ensures a smooth transition but also optimizes combustion dynamics and mixing processes under low loads, improving combustion efficiency and reducing incomplete combustion losses.

[0060] During high-load operation: the proportion of standby fuel needs to be dynamically reduced to prioritize pollutant emission control. The fuel proportion of the central standby nozzle 211 is reduced to 0%-2%, and the fuel proportion of the peripheral standby nozzle 221 is reduced to 0%-3%. At this time, although the standby fuel quantity is very low, due to the high combustion temperature, it can still effectively balance the heat release pulsation in the premixing zone and suppress thermoacoustic oscillations. The role of the standby nozzle in this stage becomes: providing rapid response capability to compensate for the inertia of the main nozzle; forming a local diffusion combustion core as a flame "anchor point" to prevent instantaneous flameout; participating in pressure fluctuation control to suppress thermoacoustic oscillations; and reducing the local flame temperature peak (e.g., from 1950℃ to 1800℃) through its diffusion combustion mode, reducing the formation of thermal NOx, while forming a temperature transition zone with the main premixing zone (Φ≈0.6), reducing the turbine inlet temperature distribution coefficient, and extending the turbine blade life.

[0061] The wide-load, low-pollution control method of this invention addresses the issues of easy flameout, low combustion efficiency, and high CO / UHC emissions at low loads. In the low-load stage, the total equivalence of the combustion chamber is relatively low, close to the lower combustible limit. The shift nozzle is activated to form a high-temperature, fuel-rich core, serving as a stable flame "anchor point." This solves the problems of easy flame extinction, low combustion efficiency, and high CO / UHC emissions at low loads, while ensuring smooth operation during combustion mode switching. In the high-load stage, the combustion temperature is high, and the role of the shift nozzle changes: even a small amount of fuel can interfere with heat release pulsations, disrupt oscillation coherence, and suppress thermoacoustic oscillations. Simultaneously, the diffusion combustion mode of the shift nozzle reduces the local flame temperature peak, decreases the formation of thermal NOx, and its fuel-rich core forms a temperature transition zone with the main premixing zone, reducing the turbine inlet temperature distribution coefficient and extending turbine blade life.

[0062] Therefore, the wide-load low-pollution control method of this invention realizes adaptive optimization control of the combustion chamber under all operating conditions, and solves the coupling contradiction between low-load stability and high-load low emissions / oscillation suppression during wide-load operation.

[0063] Furthermore, the wide-load, low-pollution control method of this invention is preferably closed-loop control. That is, based on the real-time load signal of the gas turbine and the combustion chamber pressure pulsation (thermoacoustic oscillation) signal, the fuel distribution ratio between the center and the periphery, and between the main nozzle and the standby nozzle, is adjusted in a closed loop. For example, the main nozzle flow rate can be dynamically adjusted ±20% based on a reference value, and the standby nozzle can be adjusted ±5% to ensure that the fuel-air mixing rate quickly matches load changes and eliminates combustion lag.

[0064] The control system acquires in real-time load command signals, actual power signals, and pressure pulsation (thermoacoustic oscillation) signals measured by multiple pressure sensors located in the combustion chamber from the gas turbine. Based on these real-time signals, the controller dynamically calculates and outputs commands to regulate the fuel flow of the central duty nozzle 211 and peripheral duty nozzles 221 in a closed-loop manner. For example, when the amplitude of a pressure pulsation at a specific frequency exceeds a threshold, the controller can fine-tune and increase the duty fuel ratio to inject disturbance and disrupt the coherence of the oscillation. When the load command changes rapidly, the controller can quickly adjust the duty fuel ratio to compensate for the inertia of the main nozzle fuel supply system, ensuring that the fuel-air mixing rate matches the load changes in real time.

[0065] It is important to note that during the execution of the control method, whenever fuel supply to a central control nozzle 211 or peripheral control nozzle 221 needs to be cut off according to operating conditions, such as reducing the ratio or shutting down during high-load phases, the safety protocol is immediately triggered. The controller command corresponding to the purging air system starts, and the purging valve must open within less than 1.2 seconds. The purging air continuously purges the corresponding fuel passage at a flow rate between 10 m / s and 60 m / s (the corresponding range is selected according to whether it is a central or peripheral pipeline). The purging process continues until the residual fuel volume concentration in the fuel passage is confirmed to be below 0.1% by sensors or based on a time / flow model.

[0066] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0067] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0068] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0069] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0070] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0071] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A heavy-duty gas turbine combustion chamber, characterized in that, include: The combustion chamber head includes an end cap, a hood installed downstream of the end cap, and a fairing disposed between the hood and the end cap. Multiple nozzles are mounted on the end cap and pass through an internal channel provided by the cap. The multiple nozzles include a central nozzle located at the radial center and multiple peripheral nozzles arranged in a ring array around the central nozzle. The flow area of ​​the central nozzle is larger than the flow area of ​​any of the peripheral nozzles. At least two adjacent peripheral nozzles are configured to have opposite swirl directions. Each nozzle has a standby nozzle, which includes a fuel injection orifice located at the end of the nozzle.

2. The heavy-duty gas turbine combustion chamber according to claim 1, characterized in that, The ratio of the flow area of ​​the peripheral nozzle to the flow area of ​​the central nozzle is 0.6 to 0.

8.

3. The heavy-duty gas turbine combustion chamber according to claim 1, characterized in that, The fairing is provided with multiple rectifier holes and at least one guide plate. The guide plate is located downstream of the rectifier holes and is used to distribute the airflow to the central nozzle and the peripheral nozzle.

4. The heavy-duty gas turbine combustion chamber according to claim 1, characterized in that, Each of the duty nozzles also includes a purge air system connected to the fuel passage of the duty nozzle, the purge air system being configured to introduce purge air into the fuel passage after the fuel supply to the corresponding duty nozzle is cut off.

5. The heavy-duty gas turbine combustion chamber according to claim 1, characterized in that, Each of the duty nozzles is also provided with at least one cooling hole at its end, which is connected to the cleaning air channel or cooling air source.

6. The heavy-duty gas turbine combustion chamber according to claim 5, characterized in that, The diameter of the cooling hole is 1 mm to 2.5 mm, and the amount of cooling air supplied by the cooling hole accounts for 0.1% to 0.5% of the total air flow in the combustion chamber.

7. The heavy-duty gas turbine combustion chamber according to claim 1, characterized in that, The peripheral nozzles are divided into at least two groups according to the swirling direction. The peripheral nozzles in each group have the same swirling direction, and the swirling directions between different groups are opposite.

8. A method for wide-load, low-pollution control of a heavy-duty gas turbine combustor as described in any one of claims 1-5, characterized in that, include: During the ignition phase of the heavy-duty gas turbine, fuel is supplied to the duty nozzles in the central nozzle and the peripheral nozzles. The fuel quantity supplied to the central duty nozzle accounts for 2% to 15% of the total fuel quantity, and the fuel quantity supplied to the peripheral duty nozzle accounts for 2% to 10% of the total fuel quantity. During the speed increase and low load operation phases of heavy-duty gas turbines, the fuel supply ratio between the central duty nozzle and the peripheral duty nozzles should be adjusted so that the fuel quantity of the central duty nozzle is maintained at 1% to 5% and the fuel quantity of the peripheral duty nozzle is maintained at 1% to 6%. During the high-load operation phase of heavy-duty gas turbines, the fuel supply ratio between the central duty nozzle and the peripheral duty nozzles is reduced, so that the fuel quantity of the central duty nozzle is reduced to 0% to 2% and the fuel quantity of the peripheral duty nozzle is reduced to 0% to 3%.

9. The wide-load, low-pollution control method according to claim 8, characterized in that, Based on the real-time load signal and combustion chamber pressure pulsation signal of the heavy-duty gas turbine, the fuel flow of the central and peripheral control nozzles is controlled in a closed loop.

10. The wide-load, low-pollution control method according to claim 8, characterized in that, When the fuel supply to any duty nozzle is cut off, the corresponding purging air system is activated. The purging valve in the purging air system has a response time of less than 1.2 seconds, and the purging air flow rate is maintained between 10 m / s and 60 m / s until the fuel residual volume concentration in the fuel passage of the duty nozzle is less than 0.1%.

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