Wide-fuel-adaptability nozzle suitable for hydrogen fuel

Abstract

The invention aims to provide a wide-fuel-adaptability nozzle suitable for hydrogen fuel, and belongs to the field of gas turbine nozzles. The structure that the micro fuel holes are inserted into the micro premixing channel is designed, it is guaranteed that premixed air and gas fuel are spread in the same direction, the premixed air prevents the gas fuel from making contact with the inner wall face of the channel, and tempering of a boundary layer is prevented; the premixing channel has a rotational flow angle, so that tempering can be effectively prevented; the outlet surface of the micro-premixing section is integrally designed into a concave surface, so that the ignition reliability is ensured, and the combustion stability is improved; and a radial grading strategy is adopted, and efficient, stable and low-emission combustion under different working conditions is met. Besides, the micro-premixing channel is designed in a split mode, and the micro-premixing channel is characterized in that the whole machine can burn pure natural gas fuel, pure hydrogen fuel and natural gas and hydrogen mixed fuel only by replacing the small part, namely the outlet section of the micro-premixing section, time is greatly saved, and good economical efficiency is achieved.

Description

Technical Field

[0001] The present invention relates to a nozzle, specifically a hydrogen fuel nozzle. Background Art

[0002] Hydrogen fuel gas turbines have broad application prospects in the future energy system. They have good scalability and can adapt to different hydrogen production capabilities and energy storage methods to meet the usage requirements of application scenarios such as hydrogen energy power generation, ship power, and pipeline transportation. It is a feasible solution to achieve low-carbon and distributed energy applications.

[0003] Hydrogen fuel is different from fuels commonly used in gas turbines such as natural gas. Its unique diffusion and combustion characteristics bring a series of challenges to the operation of the combustion chamber, including flashback, autoignition, nitrogen oxide emissions, and thermoacoustic oscillation characteristics. Therefore, how to prevent flashback and efficiently organize the combustion field to achieve efficient, stable, and low-emission combustion of the hydrogen fuel combustion chamber is the top priority in the engineering application of hydrogen fuel gas turbines. Therefore, a hydrogen fuel nozzle is urgently needed. Summary of the Invention

[0004] The purpose of the present invention is to provide a wide fuel adaptability nozzle suitable for hydrogen fuel that can meet the usage requirements of pure natural gas fuel, pure hydrogen fuel, and a mixture of natural gas and hydrogen, and at the same time ensure that the performance of the combustion chamber under different working conditions meets the overall performance requirements of the gas turbine.

[0005] The purpose of the present invention is achieved as follows:

[0006] A wide fuel adaptability nozzle suitable for hydrogen fuel according to the present invention is characterized in that it includes an interface part, a bent connection part, a fuel path part, and a micro-premixing channel. The interface part, the bent connection part, the fuel path part, and the micro-premixing channel are connected in sequence. The interface part is respectively provided with a liquid fuel interface, an auxiliary atomizing air interface, a primary gas fuel interface, and a secondary gas fuel interface. The bent connection part is respectively provided with a liquid fuel hole, an auxiliary atomizing air annular channel, a primary gas fuel hole, and a secondary gas fuel hole. The fuel path part is respectively provided with a diesel fuel path, an auxiliary atomizing air path, a primary gas fuel path, and a secondary gas fuel path. The liquid fuel interface is connected to the diesel fuel path, the auxiliary atomizing air interface is connected to the auxiliary atomizing air path through the auxiliary atomizing air annular channel, the primary gas fuel interface is connected to the primary gas fuel path through the primary gas fuel hole, and the secondary gas fuel interface is connected to the secondary gas fuel path through the secondary gas fuel hole. A liquid fuel swirler is provided at the end of the diesel fuel path; the fuel path part is provided with fuel micropores. The fuel micropores include an inner circle and an outer circle. The inner circle is connected to the primary gas fuel path, and the outer circle is connected to the secondary gas fuel path. Each fuel micropore corresponds to a micro-premixing channel, and the micro-premixing channel includes a micro-premixing channel inlet section and a micro-premixing channel outlet section.

[0007] The present invention may further include:

[0008] 1. The inlet section of the micro-premixing channel is parallel to the fuel micro-holes, the outlet section of the micro-premixing channel is angled with respect to the inlet section of the micro-premixing channel, and the inlet section and the outlet section of the micro-premixing channel are connected by bolts.

[0009] 2. The outlet section of the micro-premixing channel adopts a concave design.

[0010] 3. Nozzle cooling holes are provided outside the micro-premixing channel.

[0011] 4. When using liquid fuel, only the fuel path and the auxiliary atomizing air path are started. The fuel enters through the liquid fuel swirler located at the central axis, and the auxiliary atomizing air enters through the channel outside the fuel swirler, compresses and enters the combustion chamber together with the liquid fuel.

[0012] 5. When using gas fuel, the primary gas fuel path and the secondary gas fuel path are started. The gas fuel enters the fuel micro-holes from the primary gas fuel path and the secondary gas fuel path respectively according to the set ratio, realizing radial fuel staging.

[0013] The advantages of the present invention are as follows: The present invention realizes efficient and stable combustion of hydrogen fuel. Through the liquid fuel path and the auxiliary atomizing air path, the success rate of the whole machine startup is ensured; through the structure of inserting the fuel micro-holes into the micro-premixing channel, the fuel and the premixed air are evenly divided into several small portions, forming several small flames, controlling the combustion field temperature, and the premixed air wraps the hydrogen fuel in the center, effectively preventing flashback and reducing nitrogen oxide emissions; the micro-premixing channel is designed as a bent angle to further prevent flashback; the outlet section of the premixing channel is designed as a concave surface to promote the formation of a recirculation zone and improve combustion stability; by adopting a radial staging strategy, stable flames with appropriate temperatures can be formed in the combustion chamber under different operating conditions of the gas turbine, avoiding the generation of a large amount of nitrogen oxides due to the concentrated fuel injection position and uneven fuel-air mixing resulting in too high temperature in the local combustion zone; by replacing the single small-sized component at the outlet section of the premixing channel, combustion zones with different swirl intensities can be formed, so as to match different fuels such as pure hydrogen, pure natural gas, and the mixture of natural gas and hydrogen, achieving the purpose of wide fuel adaptability, convenience, high efficiency, and high economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic structural view of the present invention;

[0015] Figure 2 is a top view of the present invention;

[0016] Figure 3 is a sectional view taken along line A-A;

[0017] Figure 4 is a sectional view taken along line B-B;

[0018] Figure 5Schematic diagram of fuel micro pores and micro-premixed channels;

[0019] Figure 6 View of the outlet directions of fuel and premixed air. Specific embodiments

[0020] The present invention will be described in more detail with reference to the accompanying drawings as follows:

[0021] Combined with Figure 1-6 , the present invention mainly includes a micro-premixed channel inlet section 1 and a micro-premixed channel outlet section 2 as shown in Figure 1 ; a diesel fuel path 11, an auxiliary atomizing air path 12, a primary gaseous fuel path 13, a secondary gaseous fuel path 14, fuel micro pores 15, and a micro-premixed channel 16 as shown in Figure 4 .

[0022] The liquid fuel path can introduce liquid fuel during the startup, instability, and accidental flameout of a gas turbine to improve the ignition success rate and combustion stability; the primary gaseous fuel path 13 and the secondary gaseous fuel path 14 adopt a radial staging strategy, and can independently supply the combustion chamber in two paths according to the operating conditions. The primary gaseous fuel path 13 is located at the center of the nozzle. Only the primary gaseous fuel path 13 supplies fuel under low operating conditions to ensure combustion efficiency and stability. Under high operating conditions, the primary gaseous fuel path 13 and the secondary gaseous fuel path 14 supply fuel simultaneously to form a premixed gas with uniform composition, improve the temperature uniformity in the combustion zone, and reduce the generation of nitrogen oxides; the fuel micro pores 15 and the micro-premixed channel 16 form a separate micro-premixed unit. Several micro-premixed units evenly distribute the gaseous fuel and the premixed air into several portions to form several separate small flames, preventing flashback and local overheating; the fuel micro pores 15 are inserted into the micro-premixed channel 16 to allow the premixed air to wrap the gaseous fuel and propagate downstream, preventing the gaseous fuel from contacting the wall surface and preventing the hydrogen fuel from burning along the boundary layer and propagating upstream, further preventing flashback; the front section of the micro-premixed channel 16 is parallel to the fuel micro pores 15, and the rear section is designed as a channel with a certain angle to change the flow direction in the channel to prevent flashback. Moreover, the premixed channel enters the combustion chamber at a certain angle to form a stable recirculation zone in the combustion chamber to ensure combustion stability; the micro-premixed channel outlet section 2 adopts a certain concave angle design, which also promotes the formation of a stable recirculation zone in the combustion chamber and further enhances the stability of the combustion chamber. In addition, by only replacing the micro-premixed channel outlet section 2 and designing micro-premixed outlet sections 2 with different swirl angles and concavities, combustion zones with different recirculation intensities can be formed to adapt to various fuels such as pure hydrogen fuel, pure natural gas fuel, and a mixture of natural gas and hydrogen, which is convenient and efficient.

[0023] Liquid fuel enters through the liquid fuel interface 5, passes through the liquid fuel hole 9, propagates along the diesel fuel path 11 at the center of the nozzle, and finally enters the combustion chamber. The atomizing air enters through the auxiliary atomizing air interface 3, passes through the auxiliary atomizing air annular passage 8 and enters the auxiliary atomizing air path 12, and finally enters the combustion chamber, playing the role of atomizing the liquid fuel, promoting the combustion of the liquid fuel, and achieving the purpose of starting the gas turbine and stable operation of the liquid fuel.

[0024] The primary gaseous fuel and the secondary gaseous fuel adopt a radial staging strategy and can supply gaseous fuel separately. The primary gaseous fuel enters through the primary gaseous fuel interface 6 and then enters the primary gaseous fuel path 13 in the inner circle of the nozzle through the primary fuel hole 10 located in the inner circle. The secondary gaseous fuel enters through the secondary gaseous fuel interface 4 and then enters the secondary gaseous fuel path 14 in the outer circle of the nozzle through the secondary gaseous fuel hole 7 located in the inner circle. Under low operating conditions, only the primary gaseous fuel is supplied, and the fuel is concentrated at the center of the combustion chamber, ensuring sufficient fuel distribution at the center of the combustion chamber and ensuring combustion stability. As the operating condition increases, the total fuel demand increases. To avoid excessive fuel quantity in one path, too high temperature in the main combustion zone, and increased nitrogen oxide emissions, part of the fuel is supplied through the secondary gaseous fuel path, realizing uniform distribution of gaseous fuel and premixed air. The flame in one path (center) ignites the fuel in the second path, achieving the low-emission purpose under high operating conditions.

[0025] Each fuel micro-hole 15 is equipped with a micro-premixed fuel channel 16, which evenly divides the fuel and premixed air into several small portions, forming several small flames, controlling the temperature of the combustion field, effectively preventing flashback, and being able to reduce nitrogen oxide emissions. The outlet of the fuel micro-hole 15 is flush with the inlet of the micro-premixed fuel channel 16, and the gaseous fuel and premixed air propagate in the same direction. The fuel micro-hole 15 is inserted into the micro-premixed fuel channel 16 to ensure that the premixed air wraps the gaseous fuel and propagates downstream, preventing the gaseous fuel from contacting the inner wall surface of the premixed channel 16 and preventing boundary layer flashback.

[0026] When using liquid fuel, only the fuel path 11 and the auxiliary atomizing air path 12 are started. The fuel enters through the liquid fuel swirler 19 located at the central axis, and the auxiliary atomizing air enters through the passage outside the fuel swirler 19, is compressed and enters the combustion chamber together with the liquid fuel. The auxiliary atomizing air and the fuel are mixed with each other to promote the fragmentation and atomization of the fuel.

[0027] When using gaseous fuel, the primary gaseous fuel path 13 and the secondary gaseous fuel path 14 are started. The gaseous fuel enters the fuel micro-holes 15 from the primary gaseous fuel path 13 and the secondary gaseous fuel path 14 respectively according to a certain proportion. The fuel micro-holes 15 are divided into inner and outer circles. The inner circle micro-holes are for the primary gas, and the outer circle micro-holes are for the secondary gas, realizing radial staging of the fuel, and being able to achieve low emissions by adjusting the ratio of the primary and secondary.

[0028] The micro-premixing channel is divided into two parts, namely the inlet section 1 of the micro-premixing channel and the outlet section 2 of the micro-premixing channel. The inlet section 1 of the micro-premixing channel is parallel to the fuel micro-holes 15, while the outlet section 2 of the micro-premixing channel forms a certain angle with the inlet section 1 of the premixing channel, further preventing flashback. In addition, the outlet section 2 of the micro-premixing channel adopts a concave design to enhance the strength of the recirculation zone, prevent combustion instability and flameout under low load conditions, and improve combustion stability.

[0029] The inlet section 1 of the micro-premixing channel and the outlet section 2 of the micro-premixing channel are connected and fixed by fixing bolts 17, and the outlet section 2 of the micro-premixing channel is extremely convenient to disassemble and replace. The combustion characteristics such as the laminar flame propagation speed of hydrogen fuel and natural gas fuel are quite different, and the flow field organization methods required for their combustion chambers are also different. Through this patent, only by replacing the outlet section 2 of the micro-premixing channel and designing different swirl angles and concave degrees of the outlet surface, different combustion zones with different swirl intensities can be formed, so as to match different fuels such as pure hydrogen, pure natural gas, and the mixture of natural gas and hydrogen, achieving wide fuel adaptability, and the replacement is fast, simple and efficient, with a certain economy.

[0030] As Figure 6 shown, a number of nozzle cooling holes 18 are arranged on the outer circle of the nozzle. The cooling air prevents the flame from contacting the nozzle wall surface, reduces the nozzle wall temperature, prolongs the nozzle life, and improves the nozzle reliability.

Claims

1. A wide fuel adaptability nozzle suitable for hydrogen fuel, characterized by: The invention comprises an interface part, a bend part, a fuel path part and a micro-premixing channel. The interface part, the bend part, the fuel path part and the micro-premixing channel are connected in sequence. The interface part is respectively provided with a liquid fuel interface, an auxiliary atomizing air interface, a primary gas fuel interface and a secondary gas fuel interface. The bend part is respectively provided with a liquid fuel hole, an auxiliary atomizing air loop, a primary gas fuel hole and a secondary gas fuel hole. The fuel path part is respectively provided with a diesel path, an auxiliary atomizing air path, a primary gas fuel path and a secondary gas fuel path. The liquid fuel interface is connected to the diesel path, and the auxiliary atomizing air path is connected to the primary gas fuel path. The air interface is connected to the auxiliary atomizing air path through the auxiliary atomizing air ring channel, the primary gas fuel interface is connected to the primary gas fuel path through the primary gas fuel hole, the secondary gas fuel interface is connected to the secondary gas fuel path through the secondary gas fuel hole, and a liquid fuel swirler is arranged at the end of the diesel path; fuel micropores are arranged in the fuel path part, and the fuel micropores include an inner ring and an outer ring, the inner ring is connected to the primary gas fuel path, and the outer ring is connected to the secondary gas fuel path, each fuel micropore corresponds to a micro premixing channel, and the micro premixing channel includes a micro premixing channel inlet section and a micro premixing channel outlet section.

2. A wide fuel adaptability nozzle suitable for hydrogen fuel according to claim 1, characterized in that: The inlet section of the micro-premixing channel is parallel to the fuel micropores, the outlet section of the micro-premixing channel is at an angle to the inlet section of the micro-premixing channel, and the inlet section of the micro-premixing channel is connected to the outlet section of the micro-premixing channel by bolts.

3. The wide fuel adaptability nozzle suitable for hydrogen fuel according to claim 1, characterized in that: The outlet section of the micro-premixing channel adopts a concave design.

4. The wide fuel adaptability nozzle suitable for hydrogen fuel according to claim 1, characterized in that: Nozzle cooling holes are arranged outside the micro-premixing channel.

5. The wide fuel adaptability nozzle suitable for hydrogen fuel according to claim 1, characterized in that: When using liquid fuel, only the fuel line and the auxiliary atomizing air line are started, the fuel enters through the liquid fuel swirler located at the central axis, and the auxiliary atomizing air enters through the channel outside the fuel swirler, is compressed and enters the combustion chamber together with the liquid fuel.

6. The wide fuel adaptability nozzle suitable for hydrogen fuel according to claim 1, characterized in that: When using gas fuel, the primary gas fuel path and the secondary gas fuel path are started, and the gas fuel enters the fuel micropores from the primary gas fuel path and the secondary gas fuel path respectively according to the set ratio, so as to realize radial grading of the fuel.

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