A hydrogen combustion nozzle structure and a hydrogen combustion nozzle device for premixed gas

Abstract

This invention discloses a hydrogen combustion nozzle structure and device for premixed gas combustion. It involves setting several main air nozzle holes on the nozzle body, and within the nozzle body, setting a premixed gas chamber, a secondary air chamber, several premixed gas injection channels, and several mixing air nozzle holes. The premixed gas injection channels are configured such that their input ends connect to the premixed gas chamber, and their output ends are arranged around each of the main air nozzle holes. The mixing air nozzle holes are configured such that their input ends connect to the secondary air chamber, and their output ends are arranged around each of the main air nozzle holes. By replacing the fuel with a premixed gas of hydrogen and air, which then replaces hydrogen in a short-mixing-distance cross-jet flame, and in conjunction with the use of mixing air, rapid mixing, reduced flame propagation speed, reduced pressure loss, and improved system efficiency can be achieved. This solves the problems of high pressure loss and inability to completely prevent backfire and achieve intrinsic safety in existing premixed technologies for hydrogen combustion.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen combustion nozzle technology, and particularly relates to a hydrogen combustion nozzle structure and a hydrogen combustion nozzle device for premixed gas. Background Technology

[0002] In the field of hydrogen combustion, safety and emissions have always been pressing challenges. For example, in the development of hydrogen engine combustors, a key design consideration is reducing the formation of nitrogen oxides while preventing hydrogen backfire.

[0003] Hydrogen combustion primarily produces thermal nitrogen oxides. The key to reducing emissions lies in lowering the maximum temperature within the combustion chamber and reducing the area exceeding a specific temperature (1500℃). However, due to hydrogen's high lower heating value of 119.958 MJ / kg (10.789 MJ / Nm3), regardless of whether traditional diffusion combustion or the more recently popular micro-premixed combustion method is used, there will always be areas of stoichiometric combustion within the combustion chamber, inevitably resulting in localized temperatures exceeding 2000℃. This makes emission reduction difficult and limits its application potential.

[0004] Premixed combustion can reduce the equivalence ratio of the injected fuel, even to a lean state, thereby effectively reducing the combustion temperature. However, preventing backfire in hydrogen premixed combustion remains a challenge. Existing premixed technologies mainly suppress backfire by increasing the jet velocity and utilizing the wall effect. A typical approach is to inject the premixed fuel into the combustion chamber through numerous very small circular channels. However, this approach has several problems: 1) Limitations of high-speed jets: The jet velocity needed to suppress backfire needs to change with the turbulent flame velocity of hydrogen. The turbulent flame velocity of hydrogen is positively correlated with the degree of turbulence and Reynolds number, meaning that a high jet velocity increases the turbulent flame velocity of hydrogen. Conversely, to suppress backfire, the increased propagation velocity of the turbulent flame of hydrogen places even higher demands on the jet velocity. To suppress backfire, a jet velocity of over 200 m / s needs to be achieved under specific operating conditions, but this leads to significant pressure loss within the combustion chamber. However, due to the presence of the velocity boundary layer, even such a high jet velocity cannot completely prevent backfire. 2) Limitations of the wall effect: In order to destroy H2 combustion chain reaction free radicals through the wall effect, the diameter of the jet channel needs to be reduced to 1 mm or even smaller. Since the premixed gas is in a lean combustion state, the amount of air involved in the mixing is very large. Under these circumstances, the jet velocity of the premixed gas channel will be greatly increased, resulting in a huge pressure difference before and after the combustion chamber cap. This causes the pressure loss of the entire combustion chamber to be unacceptably large, and the system efficiency is severely reduced. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a hydrogen combustion nozzle structure and a hydrogen combustion nozzle device for premixed gas, so as to solve the problems of large pressure loss and inability to completely solve backfire and achieve intrinsic safety in the field of hydrogen combustion in existing premixed technology.

[0006] To solve the above problems, the technical solution of the present invention is as follows: The present invention provides a hydrogen combustion nozzle structure for a premixed gas, wherein the premixed gas is a mixture of hydrogen and air, comprising: A hydrogen combustion nozzle body, the hydrogen combustion nozzle body comprising a combustion end and an air end located at both ends in the axial direction; The hydrogen combustion nozzle body has a plurality of air nozzle ring groups extending radially outward. Each air nozzle ring group includes a main air nozzle arranged circumferentially and at intervals. The input end of the main air nozzle is connected to the air end, and the output end of the main air nozzle is connected to the combustion end. Furthermore, the hydrogen combustion nozzle body is provided with a premixed gas chamber, a secondary air chamber, several premixed gas injection channel groups and several mixed air hole groups; the premixed gas injection channel groups and the mixed air hole groups are all one-to-one corresponding to the main air injection holes; The input end of the premixed gas chamber and the input end of the secondary air chamber are both located at the air end, and are used to receive the premixed gas input and the air input, respectively. Each of the premixed gas injection channel groups includes a plurality of premixed gas injection channels. The output end of each premixed gas injection channel is configured to connect to the portion of the corresponding main air injection hole near the combustion end, and the output end of each premixed gas injection channel is arranged around the corresponding main air injection hole. The input end of each premixed gas injection channel is connected to the premixed gas chamber, and the premixed gas injection channel is configured to output premixed gas toward the main air injection hole. Each of the mixed air orifice groups includes a plurality of mixed air nozzles. The output end of each mixed air nozzle is configured to connect to the portion of the corresponding main air nozzle near the combustion end, and the output end of each mixed air nozzle is arranged around the corresponding main air nozzle. The input end of each mixed air nozzle is connected to the secondary air chamber, and the mixed air nozzle is configured to output mixed air to disperse the premixed air adhering to the orifice wall of the main air nozzle.

[0007] The hydrogen combustion nozzle structure for premixed gas of the present invention has the output end of the mixing air nozzle located downstream of the output end of the premixed gas injection channel along the airflow direction within the main air nozzle.

[0008] The hydrogen combustion nozzle structure for premixed gas of the present invention has an angle α between the mixed air output path at the output end of the mixed air nozzle and the axis of the corresponding main air nozzle, where α ≥ 45°.

[0009] The hydrogen combustion nozzle structure for premixed gas of the present invention further includes a plurality of cooling air hole groups, each corresponding to a main air nozzle; each cooling air hole group includes a plurality of cooling air nozzles, the output end of the cooling air nozzles is disposed at the combustion end and arranged around the corresponding main air nozzle; the input end of each cooling air nozzle is connected to the secondary air chamber, and the output end of the cooling air nozzle is configured to output cooling air toward the corresponding main air nozzle.

[0010] In the hydrogen combustion nozzle structure for premixed gas of the present invention, the angle between the cooling air output path at the output end of the cooling air nozzle and the axis of the corresponding main air nozzle is β, where 75°≥β≥15°.

[0011] The hydrogen combustion nozzle structure for premixed gas of the present invention has a premixed gas injection channel with a diameter of less than or equal to 1 mm and a premixed gas flow velocity of greater than or equal to 100 m / s within the premixed gas injection channel.

[0012] The hydrogen combustion nozzle structure for premixed gas of the present invention has the secondary air chamber having a central air inlet channel, an outer annular air inlet channel and at least one intermediate arc-shaped air inlet channel group at the air end. The axis of the central air intake channel is co-lined with the axis of the hydrogen combustion nozzle body, and the central air intake channel is arranged within the innermost air nozzle ring group. The axis of the outer annular air intake channel is co-linear with the axis of the hydrogen combustion nozzle body, and the outer annular air intake channel is arranged around the outermost air nozzle ring group. The intermediate arc-shaped air intake channel groups are arranged one by one between two adjacent air nozzle ring groups. The intermediate arc-shaped air intake channel group includes several intermediate arc-shaped air intake channels, and the several intermediate arc-shaped air intake channels are arranged at intervals along the circumference.

[0013] The hydrogen combustion nozzle structure for premixed gas of the present invention includes a premixed gas equalization chamber and a plurality of premixed gas distribution pipes at the input end of the premixed gas chamber. The input end of the premixed gas equalization chamber is used to connect to an external premixed gas supply device; the input end of the premixed gas distribution pipe is connected to the premixed gas equalization chamber, and the output end of the premixed gas distribution pipe is connected to the premixed gas chamber. The number of premixed gas distribution pipes matches the number of intermediate arc-shaped air intake channels, and the output end of the premixed gas distribution pipe is provided between adjacent intermediate arc-shaped air intake channels.

[0014] The hydrogen combustion nozzle structure for premixed gas of the present invention has a premixed gas output path at the output end of the premixed gas injection channel that is perpendicular to the axis of the main air nozzle.

[0015] The present invention provides a hydrogen combustion nozzle device, comprising the hydrogen combustion nozzle structure for premixed gas as described in any one of the above claims. It also includes air supply lines, hydrogen supply lines, hydrogen-air mixing tees, pressure gauges, thermometers, online component analyzers, and flame arresters; The output end of the air supply pipeline and the hydrogen supply pipeline are respectively connected to the two input ends of the hydrogen-air mixing tee. The output end of the hydrogen-air mixing tee is connected to the flame arrester through the output pipeline. The output end of the flame arrester is connected to the input end of the premixed gas chamber. The pressure gauge, the thermometer, and the online component analyzer are respectively arranged in the output pipeline.

[0016] Because of the above technical solutions, this invention has the following advantages and positive effects compared with the prior art: One embodiment of the present invention provides a plurality of main air nozzles on the hydrogen combustion nozzle body, and within the nozzle body, a premixed gas chamber, a secondary air chamber, a plurality of premixed gas injection channels, and a plurality of mixed air nozzles. The premixed gas injection channels are configured such that their input ends connect to the premixed gas chamber, and their output ends are arranged around each of the main air nozzles. The mixed air nozzles are configured such that their input ends connect to the secondary air chamber, and their output ends are arranged around each of the main air nozzles. By replacing the fuel with a premixed gas of hydrogen and air, which then replaces hydrogen in a cross-jet flame with a short mixing distance, and in conjunction with the use of mixing air, rapid mixing, reduced flame propagation speed, reduced pressure loss, and improved system efficiency can be achieved. Furthermore, it is low-cost, thus safely, economically, and efficiently reducing nitrogen oxide emissions. This solves the problems of high pressure loss and the inability to completely prevent backfire and achieve intrinsic safety in existing premixed technologies for hydrogen combustion. Attached Figure Description

[0017] Figure 1 This is a front view of a hydrogen combustion nozzle structure for premixed gas according to Embodiment 1 of the present invention; Figure 2 This is a front half-sectional view of a hydrogen combustion nozzle structure for premixed gas according to Embodiment 1 of the present invention. Figure 3 This is a right half-sectional view of a hydrogen combustion nozzle structure for premixed gas according to Embodiment 1 of the present invention. Figure 4 This is a top view of a hydrogen combustion nozzle structure for premixed gas according to Embodiment 1 of the present invention; Figure 5 This is a cross-sectional view (AA) of a hydrogen combustion nozzle structure for premixed gas according to Embodiment 1 of the present invention. Figure 6 This is a detailed enlarged view of the main nozzle outlet of a hydrogen combustion nozzle structure for premixed gas according to Embodiment 1 of the present invention. Figure 7 This is a piping and instrumentation flowchart illustrating the implementation method of the hydrogen combustion nozzle device in Embodiment 2 of the present invention.

[0018] Explanation of reference numerals in the attached diagram: 1. Premixed air fan; 2. Premixed air vent bypass; 3. Premixed air flow meter; 4. Hydrogen cylinder; 5. Hydrogen flow meter; 6. Hydrogen-air mixing tee; 7. Pressure gauge; 8. Thermometer; 9. Online component analyzer; 10. Flame arrester; 11. Hydrogen combustion nozzle structure; 11-1. Premixed gas inlet pipe; 11-2. Premixed gas equalization chamber; 11-3. Premixed gas distribution pipe; 11-4. Inner ring main nozzle; 11-5. Outer ring main nozzle; 11-6. Central air intake channel; 11-7. Middle arc-shaped air intake channel; 11-8. Outer ring air intake channel; 11-9. Premixed gas injection channel; 11-10. Mixed air nozzle; 11-11. Cooling air nozzle; 11-12. Premixed gas chamber; 11-13. Secondary air chamber. Detailed Implementation

[0019] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a hydrogen combustion nozzle structure and device for premixed gas according to the present invention. The advantages and features of the present invention will become clearer from the following description and claims.

[0020] Example 1 See Figures 1 to 6 In one embodiment, a hydrogen combustion nozzle structure for a premixed gas, wherein the premixed gas is a mixture of hydrogen and air, includes a hydrogen combustion nozzle body.

[0021] The hydrogen combustion nozzle body includes a combustion end and an air end located at both ends in the axial direction. Several air nozzle rings extend radially outward from the hydrogen combustion nozzle body. Each air nozzle ring includes a main air nozzle arranged circumferentially and at intervals. The input end of the main air nozzle is connected to the air end, and the output end of the main air nozzle is connected to the combustion end.

[0022] Furthermore, the hydrogen combustion nozzle body is equipped with a premixed gas chamber 11-12, a secondary air chamber 11-13, several sets of premixed gas injection channels 11-9, and several sets of mixed air holes. The input ends of the premixed gas chamber 11-12 and the secondary air chamber 11-13 are both located at the air end, used to receive premixed gas input and air input, respectively. The sets of premixed gas injection channels 11-9 and the sets of mixed air holes correspond one-to-one with the main air nozzles.

[0023] Each premixed gas injection channel group 11-9 includes several premixed gas injection channels 11-9. The output end of the premixed gas injection channel 11-9 is configured to connect to the portion of the corresponding main air injection hole near the combustion end, and the output end of the premixed gas injection channel 11-9 is arranged around the corresponding main air injection hole. The input end of each premixed gas injection channel 11-9 is connected to the premixed gas chamber 11-12, and the premixed gas injection channel 11-9 is configured to output premixed gas toward the main air injection hole.

[0024] Each mixed air nozzle group includes several mixed air nozzles 11-10. The output end of the mixed air nozzle 11-10 is configured to connect to the portion of the corresponding main air nozzle near the combustion end, and the output ends of the mixed air nozzles 11-10 are arranged around the corresponding main air nozzle. The input end of each mixed air nozzle 11-10 is connected to the secondary air chamber 11-13, and the mixed air nozzle 11-10 is configured to output mixed air to disperse the premixed air adhering to the orifice wall of the main air nozzle.

[0025] This embodiment sets several main air nozzles on the hydrogen combustion nozzle body, and sets premixed gas chambers 11-12, secondary air chambers 11-13, several premixed gas injection channels 11-9, and several mixed air nozzles 11-10 within the hydrogen combustion nozzle body. The premixed gas injection channels 11-9 are configured such that their input ends connect to the premixed gas chambers 11-12, and their output ends surround each of the main air nozzles. The mixed air nozzles 11-10 are configured such that their input ends connect to the secondary air chambers 11-13, and their output ends surround each of the main air nozzles. By replacing the fuel with a premixed gas of hydrogen and air, which then replaces hydrogen in the short-mixing-distance cross-jet flame, and in conjunction with the use of mixing air, rapid mixing, reduced flame propagation speed, reduced pressure loss, and improved system efficiency can be achieved. It also features low cost, thus safely, economically, and efficiently reducing nitrogen oxide emissions. This solves the problems of high pressure loss and inability to completely prevent backfire in existing premixed technologies for hydrogen combustion, thus achieving intrinsic safety.

[0026] The following description further illustrates the specific structure of the hydrogen combustion nozzle for premixed gas in this embodiment, with two sets of air nozzle rings: In this embodiment, the two sets of air nozzle rings mentioned above can be an inner air nozzle ring and an outer air nozzle ring, respectively. The inner air nozzle ring includes an inner ring main nozzle 11-4 arranged circumferentially, and the outer air nozzle ring includes an outer ring main nozzle 11-5 arranged annularly.

[0027] Furthermore, the number of inner ring main nozzles 11-4 is n², and the number of outer ring main nozzles 11-5 is 2n², where n² ≥ 4. The diameter of the main nozzles, once determined (the sum of the inner ring main nozzles 11-4 and the outer ring main nozzles 11-5), directly affects the flow velocity within the main nozzles, thus influencing the combustion chamber pressure drop and the effectiveness of rapid mixing. As a crucial structural parameter for regulating combustion chamber pressure drop and emissions, its size needs to be determined through numerical simulation and experimentation.

[0028] In this embodiment, along the airflow direction within the main air nozzles (i.e., the inner ring main nozzle 11-4 and the outer ring main nozzle 11-5), the output end of the mixing air nozzle 11-10 is located downstream of the output end of the premixed gas injection channel 11-9. After the premixed gas and the main nozzle air cross-contact, due to the significant difference in momentum, the premixed gas is compressed against the wall of the main nozzle. The purpose of setting the mixing air nozzle is to disperse the premixed gas fuel adhering to the wall, thereby increasing the mixing effect.

[0029] Furthermore, the angle between the mixed air output path at the output end of the mixed air nozzle 11-10 and the axis of the corresponding main air nozzle is α, where α ≥ 45°. Also, the mixed air nozzles 11-10 can be the same number as the premixed gas injection channels 11-9, corresponding one-to-one in circumferential orientation.

[0030] In this embodiment, the hydrogen combustion nozzle structure may further include several cooling air orifice groups, corresponding one-to-one with the main air orifices (i.e., the inner ring main orifice 11-4 and the outer ring main orifice 11-5). Each cooling air orifice group includes several cooling air orifices 11-11, the output end of which is located at the combustion end and arranged around the corresponding main air orifice. The input end of each cooling air orifice 11-11 is connected to the secondary air chamber 11-13, and the output end of the cooling air orifice 11-11 is configured to output cooling air toward the corresponding main air orifice. That is, the cooling air is a premixed gas that is obliquely ejected from the combustion surface toward the combustion chamber and ejected toward the corresponding main air orifice to form the flame. The purpose of setting the cooling air orifices 11-11 is to reduce the temperature of the potentially high-temperature area around the flame, thereby further reducing emissions.

[0031] Furthermore, the angle between the cooling air output path at the output end of the cooling air nozzle 11-11 and the axis of the corresponding main air nozzle is β, where 75°≥β≥15°. Also, the cooling air nozzles 11-11 are arranged around the main air nozzles on the combustion surface, with the same number as or twice the number of the premixed gas injection channels 11-9, and are arranged in a one-to-one or staggered manner in the circumferential orientation.

[0032] In this embodiment, the diameter of the premixed gas injection channel 11-9 can be set to be less than or equal to 1 mm. Specifically, the premixed gas injection channel 11-9 can be a cylindrical micro-hole parallel to the axial direction, and turns to be perpendicular to the axial direction at the downstream outlet, so as to spray the premixed gas laterally and form a cross jet with the air flowing from the main air nozzle, so as to facilitate the rapid completion of mixing.

[0033] Furthermore, the premixed gas injection channel 11-9 is an n3-way cylindrical bend, where n3 ≥ 8. Within the premixed gas injection channel 11-9, the flow velocity of the premixed gas exceeds 100 m / s. Combined with the wall effect of the micropores, this allows for rapid collision with the walls, destroying free radicals in the hydrogen combustion chain reaction and suppressing backfire. After reserving space for the arrangement of the mixed air nozzles 11-10, the distance h from the lateral outlet (i.e., the output end) of the premixed gas injection channel 11-9 to the downstream end cap (i.e., the combustion surface) of the nozzle should not be too large to prevent long-distance backfire within the main air nozzle, which could affect emission reduction and cause ablation of the main nozzle wall. On the other hand, increasing the value of h is beneficial for improving the mixing effect; its optimal value also needs to be determined based on numerical simulation and experiments.

[0034] In this embodiment, the input end of the secondary air cavity 11-13 can specifically be a central air intake channel 11-6, an outer annular air intake channel 11-8, and at least one intermediate arc-shaped air intake channel 11-7 located at the air end.

[0035] The axis of the central air intake passage 11-6 is co-linear with the axis of the hydrogen combustion nozzle body, and the central air intake passage 11-6 is arranged within the innermost air nozzle ring assembly. Furthermore, the central air intake passage 11-6 can be configured to extend to the end cap near the combustion surface, so that the incoming air impacts the end face (the back side of the combustion surface) and then diffuses outwards.

[0036] The axis of the outer annular air intake channel 11-8 is coaxial with the axis of the hydrogen combustion nozzle body, and the outer annular air intake channel 11-8 is arranged around the outermost air nozzle ring. Specifically, the outer annular air intake channel 11-8 can be formed by an annular wall that is axially outward and radially backward (towards the air surface) on the combustion surface.

[0037] The intermediate arc-shaped air intake channels 11-7 are arranged one by one between two adjacent air nozzle ring groups. Each intermediate arc-shaped air intake channel 11-7 group includes several intermediate arc-shaped air intake channels 11-7, which are arranged circumferentially at intervals. Specifically, each intermediate arc-shaped air intake channel 11-7 can be configured as a fan-shaped opening. Since there are two air nozzle ring groups, there is only one intermediate arc-shaped air intake channel 11-7 group, meaning several intermediate arc-shaped air intake channels 11-7 are arranged circumferentially at intervals between the inner and outer air nozzle ring groups. Further, each intermediate arc-shaped air intake channel 11-7 can have n4 fan-shaped openings, where n4 ≥ 6.

[0038] The other part of the air participating in combustion is divided into two streams. One stream, called the main injection air, is injected into the combustion chamber from the inner ring main injection hole 11-4 and the outer ring main injection hole 11-5, respectively. The other stream, called secondary air, flows into the secondary air chamber 11-13 from the central intake channel 11-6, the outer annular intake channel 11-8, and the middle arc-shaped intake channel 11-7, respectively. Dividing the secondary air into three inlets into the secondary air chamber 11-13 is to maintain the uniformity of the pressure inside the chamber and prevent backflow vortices from forming in the mixing air injection hole 11-10 and the cooling air injection hole 11-11, which could lead to backfire.

[0039] In this embodiment, the input end of the premixed gas chamber 11-12 may specifically include a premixed gas equalization chamber 11-2 and a plurality of premixed gas distribution pipes 11-3.

[0040] The input end of the premixed gas equalization chamber 11-2 is used to connect to an external premixed gas supply device via the premixed gas inlet pipe 11-1. The input ends of the premixed gas distribution pipes 11-3 are connected to the premixed gas equalization chamber 11-2, and the output ends of the premixed gas distribution pipes 11-3 are connected to the premixed gas chamber 11-12. The premixed gas enters the premixed gas equalization chamber 11-2 and undergoes pressure equalization within its interior to ensure uniform flow out from each premixed gas distribution pipe 11-3.

[0041] The number of premixed gas distribution pipes 11-3 matches the number of intermediate arc-shaped air intake channels 11-7, and each adjacent intermediate arc-shaped air intake channel 11-7 is provided with an output end of the premixed gas distribution pipe 11-3, that is, the two are arranged alternately. Furthermore, the premixed gas distribution pipe 11-3 can be n1 cylindrical pipes, where n1≥6.

[0042] The beneficial effects of the hydrogen combustion nozzle structure for premixed gas in this embodiment will be further explained below: First, a short-distance cross-jet is used near the outlet of the main air nozzle to quickly mix the air and premixed gas. This ensures the mixing effect while the shorter mixing distance also avoids large-area backfire within the main air nozzle.

[0043] Second, the mixed air at the downstream outlet of the main air nozzle blows the wall-adhering fuel up a second time, ensuring the mixing effect and thus reducing the combustion temperature. At the same time, the formation of a wall-adhering gas film also protects the wall surface of the main air nozzle.

[0044] Third, the cooling air around the main air nozzle lowers the temperature of the outer perimeter of the flame, thereby reducing the range of the high-temperature zone.

[0045] Fourth, the elongated micro-orifice design of the premixed gas injection channel 11-9 utilizes high-speed jet and the wall effect to prevent backfire of the premixed gas. Simultaneously, the increase in premixed gas volume compared to the pure hydrogen fuel flow rate is minimal, allowing the pressure drop at the fuel end to be controlled within a reasonable range.

[0046] It should be noted that the hydrogen combustion nozzle structure of this embodiment can also be applied to the combustion organization of pure hydrogen fuel and other fuels, and achieve corresponding low nitrogen oxide emission levels. Changes in the fuel application do not affect the scope of protection of this patent.

[0047] Example 2 This embodiment provides a hydrogen combustion nozzle device, including the hydrogen combustion nozzle structure for premixed gas described in Embodiment 1 above.

[0048] The hydrogen combustion nozzle device also includes an air supply line, a hydrogen supply line, a hydrogen-air mixing tee 6, a pressure gauge 7, a thermometer 8, an online component analyzer 9, and a flame arrester 10.

[0049] The output end of the air supply pipeline and the hydrogen supply pipeline are respectively connected to the two input ends of the hydrogen-air mixing tee 6. The output end of the hydrogen-air mixing tee 6 is connected to the flame arrester 10 through the output pipeline. The output end of the flame arrester 10 is connected to the input ends of the premixed gas chambers 11-12. The pressure gauge 7, thermometer 8, and online component analyzer 9 are respectively arranged on the output pipeline.

[0050] The air supply pipeline specifically includes an air pipeline, a premixed air fan 1, a premixed air vent bypass 2, and a premixed air flow meter 3. The premixed air fan 1 is located at the input end of the air pipeline. The premixed air vent bypass 2 and the premixed air flow meter 3 are both arranged on the air pipeline, with the premixed air flow meter 3 located downstream. The output end of the air pipeline is connected to a hydrogen-air mixing tee 6. The hydrogen supply pipeline specifically includes a hydrogen pipeline, a hydrogen cylinder 4 (the hydrogen cylinder 4 can also be other hydrogen storage devices), and a hydrogen flow meter 5. The two ends of the hydrogen pipeline are connected to the hydrogen cylinder 4 and the hydrogen-air mixing tee 6, respectively. The hydrogen flow meter 5 is located on the hydrogen pipeline.

[0051] In this embodiment, the hydrogen combustion nozzle device, except for a portion of the hydrogen combustion nozzle structure used for outputting premixed gas, is implemented as follows: 1. The amount of fuel hydrogen calculated based on the overall power requirements and overall efficiency is supplied by hydrogen cylinder 4, and the amount of hydrogen is controlled and adjusted as needed by hydrogen flow meter 5.

[0052] 2. The premixed air is supplied by a premixed air fan 1. The amount of premixed air is controlled and adjusted as needed by a premixed air flow meter 3, and a premixed air vent bypass 2 is provided on the air duct. The amount of premixed air and hydrogen are controlled in a proportional relationship, and the volumetric flow rate is configured according to the ratio. This ratio is strictly controlled to be "hydrogen:premixed air > 3:1", so that the premixed gas is outside the flammability limit of hydrogen, which is 4% to 75%.

[0053] 3. After the hydrogen and mixed air flow out of their respective pipes, they mix at the hydrogen-air mixing tee at point 6 and flow downstream. The high flow rate puts the premixed gas into a turbulent flow state at a high Reynolds number, allowing the hydrogen and air to be mixed evenly without the need for an additional mixing device.

[0054] IV. Downstream, the mixed hydrogen and air flow sequentially through pressure gauge 7, thermometer 8, and online component analyzer 9 to monitor the state and composition of the premixed gas in real time. These state and composition parameters are input into the SIS system, which sets up an interlocking trip protection mechanism.

[0055] Fifth, a flame arrester 10 is installed downstream before entering the hydrogen combustion nozzle structure at the user end to further ensure the safe supply of premixed gas.

[0056] By employing a method for implementing a hydrogen combustion nozzle for premixed gas, and utilizing flow ratio control, component analysis signal interlocking, and the installation of a flame arrester 10, safe premixing and supply of hydrogen and air are achieved. Using a volumetric flow meter, when the hydrogen quantity to premixed air quantity ratio is 3:1, premixing reduces the lower heating value of the fuel from 119.958 MJ / kg (10.789 MJ / Nm3) to 20.788 MJ / kg (8.0917 MJ / Nm3), lowering the potentially achievable maximum theoretical combustion temperature and the range of the high-temperature zone. Simultaneously, the premixed gas also reduces the flame propagation speed, laying a solid foundation for safely and reliably reducing the formation of thermal nitrogen oxides during hydrogen combustion.

[0057] Based on the above solutions, this embodiment and the solution of Embodiment 1 above mainly solve the following technical problems: 1. Reduce combustion temperature: Because hydrogen has a high lower heating value of 119.958 MJ / kg (10.789 MJ / Nm3), the highest theoretical combustion temperature that can be achieved is very high, and it increases almost linearly with the increase of the initial air temperature. Second, reducing flame propagation speed: Under the same equivalence ratio, the flame propagation speed of hydrogen laminar flow is several times that of conventional fuels such as methane, and the difference is even greater under turbulent combustion conditions.

[0058] Third, reduce emissions: Due to the high combustion temperature of hydrogen, it is very difficult to control the formation of thermal nitrogen oxides.

[0059] IV. Suppressing backfire: Hydrogen has high reactivity and a high flame propagation speed, making it extremely easy for backfire to occur and damage the nozzle, which in severe cases endangers the safety of the entire combustion system. 5. Reduce pressure loss: In existing hydrogen premixed combustion technology, high-speed jets and small channel diameters are required in the main nozzle orifice to suppress backfire, which leads to huge pressure loss problems and affects system efficiency. VI. Reduce retrofit costs: In the retrofit of combustion technology, unreasonable parameter design will lead to the investment in related high-power equipment or high-precision instruments, which will increase the retrofit cost. VII. Enhance safety: Special attention must be paid to safety requirements when hydrogen is mixed with other gases to fully ensure the safety of hydrogen applications.

[0060] Furthermore, based on the above solutions, this embodiment and the solutions of Embodiment 1 described above have the following beneficial effects compared with the prior art: 1. Reduce combustion temperature: By replacing the fuel with a premixed gas of hydrogen and air within a safe and reasonable range, the lower heating value of the premixed gas can be greatly reduced, thereby reducing the maximum theoretical combustion temperature that can be achieved. 2. Reduce flame propagation speed: In the premixed gas, the flame propagation speed is greatly reduced with the addition of air, which helps to lower the threshold of the jet velocity in the main nozzle that can suppress backfire.

[0061] III. Reduced Emissions: This technical solution adopts the method of "cross jet + short mixing distance + mixed air + cooling" to achieve rapid and uniform mixing of fuel and air in a limited space, avoid the formation of local high temperature points, and reduce the generation of thermal nitrogen oxides.

[0062] IV. Suppressing backfire: The amount of air added to the premixed gas is strictly controlled in proportion, and the hydrogen concentration is higher than the flammability limit range. This creates an inherent safety feature in the premixed gas channel that prevents backfire, eliminating the need for high flow rates and thus reducing the fuel gas source pressure. V. Reduced Pressure Loss: Compared to the huge pressure loss caused by the high-speed jet and small channel diameter required in the main nozzle of existing premixed technologies, this technical solution has a short mixing distance between air and premixed gas and forms a wall-adhering gas film at the main nozzle outlet, which effectively prevents the high-temperature hazards caused by flame formation in the main nozzle, reduces the dependence on high flow rate and small channel diameter, thereby reducing the pressure loss of the entire combustion chamber and improving system efficiency. VI. Reduced modification costs: Based on the extreme blending ratio of "75% hydrogen: 25% air", the air content in the premixed gas is relatively low, eliminating the need to design a large air compressor. Only a small air compressor or a gas cylinder is needed, which simplifies the design of the gas source and reduces modification costs. VII. Safety Redundancy: The premixed gas configuration includes measures such as flow ratio adjustment, state component monitoring, and flame arrester 10. Combined with the slender premixed gas injection channel 11-9 in the nozzle, safety is fully guaranteed.

[0063] In summary, compared with existing technologies, this technical solution reduces combustion temperature and flame propagation speed by changing the fuel to a premixed gas of hydrogen and air, thereby suppressing backfire and reducing emissions, reducing pressure loss and improving overall efficiency, simplifying gas source design, and having low modification costs. It also offers better safety, environmental protection and economy.

[0064] Due to the advanced nature of this technical solution, it can be widely used in the fields of "industrial hydrogen combustion nozzle system", "gas turbine combustion system" and "mixed fuel safety supply system". In the field of industrial hydrogen combustion nozzles, this technical solution's multi-dimensional and effective backfire prevention technology can be applied to the recovery and reuse of industrial by-product hydrogen for driving power or heating. In the field of gas turbine combustion systems, by replacing the fuel with a mixture of hydrogen and air, and using pure hydrogen in the rapid mixing and combustion process, the calorific value and flame propagation speed of the mixture can be reduced, thereby lowering the combustion temperature and nitrogen oxide generation, and suppressing backfire without increasing the pressure loss in the combustion chamber. This solves the two major challenges of safety and environmental protection in the hydrogen energy era. In the field of safe mixed fuel supply systems, this technical solution can be applied to gas generator sets, gas boilers, and other equipment to achieve the safe use of hydrogen premixed fuel in the energy sector, with a very wide range of applications.

[0065] In summary, safety and emissions issues remain critical challenges in hydrogen combustion. This technical solution offers a safe, feasible, economical, and environmentally friendly partially premixed hydrogen combustion method that effectively addresses the backfire problem inherent in traditional combustion methods, while also reducing combustion temperature and nitrogen oxide generation. Future market demands for safe, efficient, and environmentally friendly hydrogen combustion technologies will continue to grow, thus this technical solution possesses promising market prospects and broad market demand.

[0066] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they shall still fall within the protection scope of the present invention.

Claims

1. A hydrogen combustion nozzle structure for premixed gas, characterized in that, The premixed gas is a mixture of hydrogen and air, including: A hydrogen combustion nozzle body, the hydrogen combustion nozzle body comprising a combustion end and an air end located at both ends in the axial direction; The hydrogen combustion nozzle body has a plurality of air nozzle ring groups extending radially outward. Each air nozzle ring group includes a main air nozzle arranged circumferentially and at intervals. The input end of the main air nozzle is connected to the air end, and the output end of the main air nozzle is connected to the combustion end. Furthermore, the hydrogen combustion nozzle body is provided with a premixed gas chamber, a secondary air chamber, several premixed gas injection channel groups and several mixed air hole groups; the premixed gas injection channel groups and the mixed air hole groups are all one-to-one corresponding to the main air injection holes; The input end of the premixed gas chamber and the input end of the secondary air chamber are both located at the air end, and are used to receive the premixed gas input and the air input, respectively. Each of the premixed gas injection channel groups includes a plurality of premixed gas injection channels. The output end of each premixed gas injection channel is configured to connect to the portion of the corresponding main air injection hole near the combustion end, and the output end of each premixed gas injection channel is arranged around the corresponding main air injection hole. The input end of each premixed gas injection channel is connected to the premixed gas chamber, and the premixed gas injection channel is configured to output premixed gas toward the main air injection hole. Each of the mixed air orifice groups includes a plurality of mixed air nozzles, the output end of each mixed air nozzle is configured to connect to the portion of the corresponding main air nozzle near the combustion end, and the output end of each mixed air nozzle is arranged around the corresponding main air nozzle; the input end of each mixed air nozzle is connected to the secondary air chamber, and the mixed air nozzle is configured to output mixed air to disperse the premixed air adhering to the orifice wall of the main air nozzle; Along the airflow direction within the main air nozzle, the output end of the mixed air nozzle is located downstream of the output end of the premixed gas injection channel.

2. The hydrogen combustion nozzle structure for premixed gas as described in claim 1, characterized in that, The angle between the mixed air output path at the output end of the mixed air nozzle and the axis of the corresponding main air nozzle is α, where α ≥ 45°.

3. The hydrogen combustion nozzle structure for premixed gas as described in claim 1, characterized in that, It also includes several cooling air hole groups, each corresponding to one of the main air nozzles; each cooling air hole group includes several cooling air nozzles, the output end of the cooling air nozzles is disposed at the combustion end and arranged around the corresponding main air nozzle; the input end of each cooling air nozzle is connected to the secondary air chamber, and the output end of the cooling air nozzle is configured to output cooling air toward the corresponding main air nozzle.

4. The hydrogen combustion nozzle structure for premixed gas as described in claim 3, characterized in that, The angle between the cooling air output path at the output end of the cooling air nozzle and the axis of the corresponding main air nozzle is β, where 75°≥β≥15°.

5. The hydrogen combustion nozzle structure for premixed gas as described in claim 1, characterized in that, The diameter of the premixed gas injection channel is less than or equal to 1 mm, and the flow velocity of the premixed gas in the premixed gas injection channel is greater than or equal to 100 m / s.

6. The hydrogen combustion nozzle structure for premixed gas as described in claim 1, characterized in that, The input end of the secondary air cavity consists of a central air intake channel, an outer annular air intake channel, and at least one intermediate arc-shaped air intake channel group located at the air end. The axis of the central air intake channel is co-lined with the axis of the hydrogen combustion nozzle body, and the central air intake channel is arranged within the innermost air nozzle ring group. The axis of the outer annular air intake channel is co-linear with the axis of the hydrogen combustion nozzle body, and the outer annular air intake channel is arranged around the outermost air nozzle ring group. The intermediate arc-shaped air intake channel groups are arranged one by one between two adjacent air nozzle ring groups. The intermediate arc-shaped air intake channel group includes several intermediate arc-shaped air intake channels, and the several intermediate arc-shaped air intake channels are arranged at intervals along the circumference.

7. The hydrogen combustion nozzle structure for premixed gas as described in claim 6, characterized in that, The input end of the premixed gas chamber includes a premixed gas equalization chamber and several premixed gas distribution pipes; The input end of the premixed gas equalization chamber is used to connect to an external premixed gas supply device; the input end of the premixed gas distribution pipe is connected to the premixed gas equalization chamber, and the output end of the premixed gas distribution pipe is connected to the premixed gas chamber. The number of premixed gas distribution pipes matches the number of intermediate arc-shaped air intake channels, and the output end of the premixed gas distribution pipe is provided between adjacent intermediate arc-shaped air intake channels.

8. The hydrogen combustion nozzle structure for premixed gas as described in claim 1, characterized in that, The premixed gas output path at the output end of the premixed gas injection channel is perpendicular to the axis of the main air nozzle.

9. A hydrogen combustion nozzle device, characterized in that, Includes the hydrogen combustion nozzle structure for premixed gas as described in any one of claims 1 to 8; It also includes air supply lines, hydrogen supply lines, hydrogen-air mixing tees, pressure gauges, thermometers, online component analyzers, and flame arresters; The output end of the air supply pipeline and the hydrogen supply pipeline are respectively connected to the two input ends of the hydrogen-air mixing tee. The output end of the hydrogen-air mixing tee is connected to the flame arrester through the output pipeline. The output end of the flame arrester is connected to the input end of the premixed gas chamber. The pressure gauge, the thermometer, and the online component analyzer are respectively arranged in the output pipeline.

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