A multi-stage burner

Abstract

The application relates to a multi-stage combustor and belongs to the technical field of combustors.The multi-stage combustor comprises a multi-stage combustor body, a central combustion zone, a peripheral combustion zone and a cross-section adjustable air supply system; the multi-stage combustor body has an inner-outer nested structure; the central combustion zone comprises an array type combustor arranged in the central region of the multi-stage combustor body; the peripheral combustion zone comprises an annular hole combustor coaxially arranged outside the array type combustor; and the cross-section adjustable air supply system comprises an air channel adjusting mechanism arranged outside the array type combustor; the application provides a multi-stage combustor, air flow and flow speed are dynamically regulated through the air channel adjusting mechanism, and combustion stability is improved; independent adjusting devices are arranged at the central and peripheral fuel outlets, fuel flow is finely controlled, and flame form is optimized; partition combustion reduces NOx generation, carbon smoke particles are completely oxidized in the peripheral zone, low emission is realized, modular design facilitates installation and maintenance, and operation is simple, flexible and convenient.

Description

Technical Field

[0001] This invention relates to a multi-stage burner, belonging to the field of burner technology. Background Technology

[0002] Industrial furnaces are core equipment in industrial thermal processing processes such as petroleum cracking, metal raw material melting, raw material sintering, and heat treatment. The burner, as the core heating component of the industrial furnace, is responsible for converting the chemical energy of combustible fuel into thermal energy, providing a stable and controllable heat source for the furnace processes. Its combustion control performance, thermal efficiency, and emission characteristics directly determine the operational quality and environmental compliance of the industrial furnace. To achieve staged combustion and optimize heat distribution, existing industrial furnace burners generally adopt a structure combining multiple sets of the same type of combustion units. Each combustion unit can independently complete fuel injection, mixing, and combustion, attempting to improve combustion stability and heat output uniformity through multi-unit synergy.

[0003] The air supply passage of existing burners has a fixed cross-section structure, which cannot dynamically adjust the air flow cross-sectional area and injection velocity according to combustion load, fuel type and operating conditions. It is impossible to ensure the rigidity of the central flame by increasing the air velocity, and it is also difficult to adjust the air flow to optimize the fuel and air mixing effect as needed. The air-fuel ratio matching accuracy is poor and the adaptability to combustion conditions is extremely poor.

[0004] The central combustion zone uses an integrated fuel distribution method, which makes it impossible to independently control the fuel flow of each fuel outlet; the fuel outlets in the outer combustion zone also lack independent control mechanisms, resulting in the inability to accurately control the air-fuel ratio in the central zone, outer zone, and individual combustion units, and making it difficult to optimize the flame shape and combustion intensity as needed.

[0005] The burner nozzle has a fixed and non-replaceable structure, which cannot be adapted to green fuels with different physical and chemical properties such as hydrogen, methanol, and green ammonia; the fuel injection angle, atomization effect, and jet pattern are fixed, the central flame is not compact enough, and the coordination effect with the peripheral flame is poor, making it difficult to enhance the flame radiation performance. Summary of the Invention

[0006] This invention provides a multi-stage burner to solve the problems of the prior art, such as the inability to dynamically control the air supply, the lack of independent and fine adjustment capability of the fuel flow, and poor fuel adaptability and flame synergy.

[0007] This invention provides a multi-stage burner, comprising:

[0008] A multi-stage burner body, wherein the multi-stage burner body has an inner and outer nested structure;

[0009] The central combustion zone includes an array of burners located in the central region of the multi-stage burner body;

[0010] The peripheral combustion zone includes an annular burner coaxially disposed outside the array burner;

[0011] An adjustable cross-section air supply system includes an air passage adjustment mechanism disposed outside the array burner;

[0012] The array burner includes multiple central fuel outlets and a central fuel distribution regulating device for supplying fuel to the central fuel outlets. The central fuel distribution regulating device is configured to independently regulate the fuel flow rate entering each of the central fuel outlets or their corresponding fuel lines. Each of the central fuel outlets is independently connected to a second fuel line.

[0013] Furthermore, the annular burner includes multiple peripheral fuel outlets and peripheral fuel independent control devices corresponding to each peripheral fuel outlet, each peripheral fuel independent control device being configured to independently adjust the fuel flow rate entering its corresponding peripheral fuel outlet.

[0014] Preferably, the air passage adjustment mechanism includes an inner wall surface and a first-stage piston and a second-stage piston concentrically mounted on each other. Both the first-stage piston and the second-stage piston are constructed into a cylindrical structure, and the first-stage piston and the second-stage piston are connected by a threaded structure, so that the first-stage piston and the second-stage piston can be axially adjusted relative to the inner wall surface through the threaded structure, thereby changing the equivalent flow cross-sectional area of ​​the annular air passage formed by the ends of the pistons and the inner wall surface.

[0015] The central fuel distribution regulating device includes a rectifier, which includes a plurality of fan-shaped baffles and fastening studs for securing each of the fan-shaped baffles.

[0016] The multiple fuel distribution pipes are connected to a main fuel pipe via a flow distribution regulating device;

[0017] Multiple fan-shaped baffles are arranged in the same plane and closely fitted to each other. Each fan-shaped baffle is configured to rotate independently about its central axis and is fixed in its adjustment position by the fastening studs, so that each fan-shaped baffle can independently change the flow area of ​​the fuel pipe inlet it covers.

[0018] The number of the fan-shaped flow-blocking plates is three, and the included angle of the fan-shaped flow-blocking plate of each fan-shaped flow-blocking plate is 120°;

[0019] The multi-stage burner body is provided with a fixed support, and multiple second fuel pipes are located inside the fixed support. The fixed support positions and supports the multiple second fuel pipes.

[0020] The array burner includes nine central fuel outlets, which are arranged in an array.

[0021] The annular burner includes twelve peripheral fuel outlets, which are circumferentially distributed at equal intervals on the multi-stage burner body.

[0022] Each of the central fuel outlets is provided with a threaded connection structure at its upper end for detachable installation of different types of nozzles;

[0023] Each of the peripheral fuel outlets is provided with a frustum-shaped nozzle inside. The frustum-shaped nozzle is arranged in a gradually expanding conical shape, and each frustum-shaped nozzle is independently provided with an outer air layer composed of an annular channel on its outer side.

[0024] The peripheral fuel independent control device includes an independent regulating valve, which includes a valve tube, a valve core, a valve stem, and a spring. The valve tube is connected to the first fuel tube and the methanol flow channel corresponding to the peripheral fuel outlet. The valve core is disposed inside the valve tube and is used to block the passage between the first fuel tube and the methanol flow channel. The valve stem is threaded to the valve tube, and the valve stem and the valve core are connected by the spring. Thus, by rotating the valve stem, the valve core is moved to finely adjust the fuel flow rate entering the peripheral fuel outlet.

[0025] The diameter of each of the central fuel outlets of the array burner is 1.5 mm, and the center distance between adjacent central fuel outlets is 12 mm.

[0026] The diameter of each of the peripheral fuel outlets of the annular burner is 1.7 mm.

[0027] The small end radius of the frustum-shaped nozzle is 4 mm, the large end radius is 10 mm, and the channel radius of the outer air layer surrounding the frustum-shaped nozzle is 12 mm.

[0028] The beneficial effects of this invention are:

[0029] This invention provides a multi-stage burner that achieves dynamic adjustment of airflow cross-sectional area and injection velocity through an air channel adjustment mechanism. This allows the burner to precisely control airflow and velocity according to combustion load, fuel type, and operating conditions, thereby improving the rigidity of the central flame, optimizing the fuel-air mixing effect, and enhancing the air-fuel ratio matching accuracy and combustion condition adaptability.

[0030] The array burner achieves independent adjustment of the fuel flow rate at each central fuel outlet through a central fuel distribution regulating device, allowing for precise control of the flow rate at each fuel outlet, thereby optimizing the flame pattern and combustion intensity;

[0031] Each peripheral fuel outlet of the annular burner is equipped with an independent control device, which can independently adjust the fuel flow of each peripheral fuel outlet, realize flexible zone control of the peripheral flame, ensure the uniformity and stability of the peripheral flame, and improve combustion efficiency.

[0032] The central fuel outlet adopts a detachable threaded connection structure, which allows for the installation of different types of nozzles to accommodate green fuels with different physicochemical properties, such as hydrogen, methanol, and green ammonia. By adjusting the nozzle type, fuel injection angle, and atomization effect, the synergy between the central flame and the peripheral flame can be optimized, and the compactness and radiation performance of the flame can be improved.

[0033] By dividing the combustion process into a central smoke-generating zone, a mixing and control zone, and a peripheral oxidation zone, the formation of local high-temperature oxygen-rich zones is avoided, thereby suppressing the generation of thermal NOx. The carbon soot particles generated in the central zone are fully oxidized and burned when flowing through the high-temperature peripheral oxygen-rich zone, thus avoiding the direct emission of particulate matter. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall structure of a multi-stage burner according to the present invention.

[0035] Figure 2 This is a schematic diagram of the exploded structure of a multi-stage burner according to the present invention.

[0036] Figure 3 This is a partial exploded structural diagram of a multi-stage burner according to the present invention.

[0037] Figure 4 This is a schematic diagram of the rectifier structure of a multi-stage burner according to the present invention.

[0038] Figure 5 This is a schematic diagram of the exploded structure of the rectifier of a multi-stage burner according to the present invention.

[0039] Figure 6 This is a schematic diagram of the regulating valve structure of a multi-stage burner according to the present invention.

[0040] Figure 7 This is a schematic diagram of the exploded structure of the regulating valve of a multi-stage burner according to the present invention.

[0041] Figure 8 This is a schematic diagram of another exploded structure of the regulating valve of a multi-stage burner according to the present invention.

[0042] In the diagram: 1. Multistage burner body; 11. Shell; 12. Methanol flow channel; 2. Annular orifice burner; 21. Peripheral fuel outlet; 211. Frustum-shaped nozzle; 22. First fuel pipe; 23. Regulating valve; 231. Valve stem; 232. Valve pipe; 233. Spring; 234. Valve core; 3. Array burner; 31. Central fuel outlet; 311. Threaded connection structure; 32. Second fuel pipe; 4. Air passage regulating mechanism; 41. First stage piston; 42. Second stage piston; 5. Rectifier; 51. Fan-shaped baffle; 52. Fastening stud; 6. Fixed bracket; 7. Main fuel pipe. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] This embodiment provides a multi-stage burner, including a multi-stage burner body 1, wherein the multi-stage burner body 1 has an inner and outer nested structure, including a central combustion zone, an outer combustion zone, and an adjustable air supply system. The central combustion zone includes an array burner 3, which is located in the central region of the multi-stage burner body 1. The outer combustion zone includes an annular burner 2, which is coaxially arranged outside the array burner 3. The adjustable air supply system includes an air passage adjustment mechanism 4 arranged outside the array burner 3.

[0045] In one embodiment, the array burner 3 includes nine central fuel outlets 31, which are arranged in an array. Each central fuel outlet 31 has a threaded connection structure 311 at its upper end for detachably installing different types of nozzles. By replacing the nozzles, the fuel injection angle, atomization effect and jet pattern can be flexibly adjusted to adapt to different fuel types and combustion conditions.

[0046] The diameter of the central fuel outlet 31 is 1.5 mm, and the center distance between adjacent holes is 12 mm, thereby ensuring the compactness of the central flame and its coordination with the peripheral flame.

[0047] The tail of the nine central fuel outlets 31 is composed of nine independent second fuel pipes 32. The second fuel pipes 32 are arranged in a circumferential linear manner and are connected to the main fuel pipe 7 through a rectifier 5. The rectifier 5 is used to distribute and regulate the fuel flow rate entering the second fuel pipes 32.

[0048] In a preferred embodiment, the rectifier 5 includes three fan-shaped baffles 51, each with a fan-shaped angle of 120°. The three fan-shaped baffles 51 are coaxially arranged in the same plane and closely fitted to each other. Each fan-shaped baffle 51 can rotate independently around its central axis and is fixed in its adjusted position by a fastening stud 52. By independently rotating any fan-shaped baffle 51, the flow area of ​​the inlet of the second fuel pipe 32 it covers can be changed, thereby achieving independent adjustment of the flow rate of the second fuel pipe 32 without affecting the air layer seal. The multi-stage burner body 1 is provided with a fixed bracket 6 that matches the second fuel pipe 32, and the second fuel pipe 32 is located inside the fixed bracket 6.

[0049] In one embodiment, the air passage adjustment mechanism 4 includes an inner wall surface and a first-stage piston 41 and a second-stage piston 42 concentrically arranged with each other. The first-stage piston 41 and the second-stage piston 42 are both constructed into cylindrical structures. The first-stage piston 41 and the second-stage piston 42 are threadedly connected. The first-stage piston 41, the second-stage piston 42 and the inner wall surface between them are all axially adjusted through the threaded structure.

[0050] During operation, the effective flow boundary of the air outlet can be changed by rotating or driving the first-stage piston 41 and the second-stage piston 42 to move back and forth axially. Specifically, when the piston moves axially, the equivalent flow cross-sectional area of ​​the annular air passage formed by the piston end and the inner wall surface is changed, thereby achieving continuous adjustment from large to small or from small to large. This allows for precise dynamic control of airflow and injection velocity to adapt to the needs of different loads and combustion states.

[0051] The annular burner 2 is located outside the array burner 3 and is used to form an outer flame, provide the main heat, and generate the soot required for enhanced radiation.

[0052] In a preferred embodiment, the annular burner 2 includes twelve peripheral fuel outlets 21, which are circumferentially distributed at equal intervals on the multi-stage burner body 1, and the diameter of each peripheral fuel outlet 21 is, for example, 1.7 mm.

[0053] To better mix with air and control the flame shape, each peripheral fuel outlet 21 is equipped with a frustum-shaped nozzle 211, which is located inside the peripheral fuel outlet 21. The frustum-shaped nozzle 211 is cone-shaped and gradually expands, which is conducive to stable fuel injection and entrainment and mixing with peripheral air. The radius of the small end of the frustum-shaped nozzle 211 is 4mm and the radius of the large end is 10mm.

[0054] Furthermore, each of the frustum-shaped nozzles 211 has an independent outer air layer. The outer air layer is composed of an annular channel surrounding the frustum-shaped nozzle 211 with a channel radius of 12 mm, which ensures that each outer fuel nozzle has a stable and controllable oxidant environment.

[0055] The frustum-shaped nozzle 211 is provided with a corresponding first fuel pipe 22, and the first fuel pipe 22 is provided with a regulating valve 23. By adjusting the regulating valve 23, the fuel flow of each frustum-shaped nozzle 211 can be finely adjusted independently, thereby realizing flexible zone control of the peripheral flame.

[0056] The multi-stage burner body 1 includes a housing 11 covering the annular burner 2, wherein the housing 11 is provided with a methanol flow channel 12 that matches the annular burner 2, and the methanol flow channel 12 is in communication with the first fuel pipe 22.

[0057] In a preferred embodiment, the regulating valve 23 includes a valve tube 232 located between the first fuel pipe 22 and the methanol flow channel 12. A valve core 234 is provided inside the valve tube 232. The methanol flow channel 12 and the first fuel pipe 22 are located at both ends of the valve tube 232 and communicate with each other. The first fuel pipe 22 and the methanol flow channel 12 are blocked by the valve core 234, so that the fuel flow of the peripheral fuel outlet 21 can be finely adjusted independently, thereby realizing flexible zone control of the peripheral flame. A valve stem 231 with a threaded connection is provided on the valve tube 232. The valve stem 231 and the valve core 234 are connected by a spring 233.

[0058] In operation, the air supply regulator first adjusts the equivalent flow cross-sectional area of ​​the air passage regulating mechanism 4 by rotating the first-stage piston 41 and the second-stage piston 42 according to the target load and combustion state. For example, when it is necessary to increase the rigidity of the center flame, the air passage cross-sectional area can be reduced to increase the air velocity; when it is necessary to enhance mixing, the cross-sectional area can be increased to increase the air flow. At the same time, the amount of fuel entering each fuel pipe of the nine-hole burner 200 can be finely adjusted by independently rotating the fan-shaped baffle 51 in the rectifier 5.

[0059] Secondly, fuel supply and staged combustion are carried out. The main fuel, such as hydrogen, methanol, green ammonia, or mixed fuel with a small amount of smoke-generating components, is supplied to the array burner 3 through the main fuel pipe 7 and the second fuel pipe 32. At the same time, fuel is supplied to the annular burner 2 through the first fuel pipe 22 and the methanol flow channel 12 in cooperation with the regulating valve 23. The fuel can be the same as or different from the central fuel. Air can be supplied to the central area and the outer area respectively through the air channel regulating mechanism 4 and the outer air layer.

[0060] Under the aforementioned supply conditions, the ignition device is activated to ignite the burner. During combustion, the array burner 3 generates one or more central flames. Enveloped by the peripheral flames generated by the annular burner 2 and subjected to high temperatures, a trace amount of soot particles can be induced to form in the central flame zone or the area between the central and peripheral flames by precisely controlling the air-fuel ratio in the central and peripheral zones. These soot particles have extremely high thermal emissivity, thus forming a multi-level superimposed radiation enhancement effect, achieving a leverage amplification effect on the flame radiation intensity. Simultaneously, because the combustion process is divided into a central smoke-forming zone (array burner 3 zone), a mixing and control zone (air channel regulating mechanism 4 zone), and a peripheral oxidation zone (annular burner 2 zone), the combustion reaction proceeds spatially in zones, avoiding localized high temperatures, which is beneficial for reducing the formation of nitrogen oxides (NOx) and achieving low emissions. Finally, the soot particles generated in the central zone are fully oxidized and burned when flowing through the high-temperature, oxygen-rich peripheral zone, avoiding direct emissions of particulate matter.

[0061] Compared with existing designs, the array burner's 3-nine-hole array layout forms a compact central flame. With replaceable nozzles, it can adapt to different fuel characteristics such as hydrogen, methanol, and green ammonia. By adjusting the injection angle / atomization effect, it can achieve precise generation of soot particles. The three-fan-shaped baffles 51 of the rectifier 55 can independently adjust the flow rate of each fuel pipe, achieving fine control of the air-fuel ratio in the central area without affecting the air layer seal. This induces the generation of trace soot, forming a radiation-enhanced leverage effect of central soot formation and peripheral oxidation.

[0062] The two-stage piston achieves dynamic matching of airflow / velocity by adjusting the cross-sectional area of ​​the annular channel axially via a thread. For example, reducing the cross-sectional area can increase the airflow velocity and enhance the rigidity of the central flame, while increasing the cross-sectional area can increase the airflow, promote mixing, and adapt to load fluctuations.

[0063] The annular burner 21 features 21 fuel outlets 21 evenly spaced around its periphery, which, together with the frustum-shaped nozzles 211, enhances the entrainment and mixing of fuel with the surrounding air layer. Independent regulating valves 23 allow for precise control of fuel flow in each nozzle zone, ensuring a rich oxygen environment that promotes complete oxidation of soot particles and prevents direct particulate matter emissions.

[0064] Spatial partitioned combustion avoids local high-temperature oxygen-rich zones, suppresses the formation of thermal NOx, and dynamically adjusts the air-fuel ratio.

[0065] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A multi-stage burner, characterized in that, include: A multi-stage burner body (1) has an inner and outer nested structure; The central combustion zone includes an array of burners (3) located in the central region of the multi-stage burner body (1). The outer combustion zone includes an annular hole burner (2) coaxially arranged outside the array burner (3); An adjustable cross-section air supply system includes an air passage adjustment mechanism (4) disposed outside the array burner (3). The array burner (3) includes multiple central fuel outlets (31) and a central fuel distribution regulating device for supplying fuel to the central fuel outlets (31). The central fuel distribution regulating device is configured to independently regulate the fuel flow into each of the central fuel outlets (31) or its corresponding fuel line. Each of the central fuel outlets (31) is independently connected to a second fuel line (32). Furthermore, the annular burner (2) includes a plurality of peripheral fuel outlets (21) and a peripheral fuel independent control device corresponding to each of the peripheral fuel outlets (21), each of the peripheral fuel independent control devices being configured to independently regulate the fuel flow into its corresponding peripheral fuel outlet (21).

2. The multi-stage burner according to claim 1, characterized in that: The air passage adjustment mechanism (4) includes an inner wall surface and a first-stage piston (41) and a second-stage piston (42) concentrically mounted on each other. The first-stage piston (41) and the second-stage piston (42) are both constructed as cylindrical structures, and the first-stage piston (41) and the second-stage piston (42) are connected by a threaded structure, so that the first-stage piston (41) and the second-stage piston (42) can be axially adjusted relative to the inner wall surface through the threaded structure, thereby changing the equivalent flow cross-sectional area of ​​the annular air passage formed by the end of the piston and the inner wall surface.

3. The multi-stage burner according to claim 1, characterized in that: The central fuel distribution regulating device includes a rectifier (5), which includes a plurality of fan-shaped baffles (51) and a fastening stud (52) for fixing each of the fan-shaped baffles (51). The multiple fuel distribution pipes (32) are connected to a main fuel pipe (7) via a flow distribution regulating device (5); Multiple fan-shaped baffles (51) are arranged in the same plane and closely fitted to each other. Each fan-shaped baffle (51) is configured to rotate independently about its central axis and is fixed in its adjustment position by the fastening stud (52), so that each fan-shaped baffle (51) can independently change the flow area of ​​the fuel pipe inlet it covers.

4. The multi-stage burner according to claim 3, characterized in that: The number of the fan-shaped flow-blocking plates (51) is three, and the fan-shaped included angle of each fan-shaped flow-blocking plate (51) is 120°; The multi-stage burner body (1) is provided with a fixed bracket (6), and multiple second fuel pipes (32) are located inside the fixed bracket (6). The fixed bracket (6) positions and supports the multiple second fuel pipes (32).

5. The multi-stage burner according to claim 1, characterized in that: The array burner (3) includes nine central fuel outlets (31) arranged in an array. The annular burner (2) includes twelve peripheral fuel outlets (21), which are circumferentially distributed at equal intervals on the multi-stage burner body (1).

6. The multi-stage burner according to claim 1, characterized in that: Each of the central fuel outlets (31) is provided with a threaded connection structure (311) at its upper end for detachable installation of different types of nozzles; Each of the peripheral fuel outlets (21) is provided with a frustum-shaped nozzle (211) inside. The frustum-shaped nozzle (211) is arranged in a conical shape and gradually expands. Each frustum-shaped nozzle (211) is independently provided with an outer air layer composed of an annular channel on its outer side.

7. The multi-stage burner according to claim 6, characterized in that: The peripheral fuel independent control device includes an independent regulating valve (23). The independent regulating valve (23) includes a valve tube (232), a valve core (234), a valve stem (231), and a spring (233). The valve tube (232) is connected to the corresponding first fuel tube (22) and methanol flow channel (12) of the peripheral fuel outlet (21). The valve core (234) is disposed inside the valve tube (232) and is used to block the passage between the first fuel tube (22) and the methanol flow channel (12). The valve stem (231) is threaded to the valve tube (232). The valve stem (231) and the valve core (234) are connected by the spring (233). Thus, by rotating the valve stem (231), the valve core (234) is moved to finely regulate the fuel flow rate entering the peripheral fuel outlet (21).

8. The multi-stage burner according to claim 1, characterized in that: The diameter of each of the central fuel outlets (31) of the array burner (3) is 1.5 mm, and the center distance between adjacent central fuel outlets (31) is 12 mm. The diameter of each of the peripheral fuel outlets (21) of the annular burner (2) is 1.7 mm.

9. The multi-stage burner according to claim 6, characterized in that: The small end radius of the frustum-shaped nozzle (211) is 4 mm, the large end radius is 10 mm, and the channel radius of the outer air layer surrounding the frustum-shaped nozzle (211) is 12 mm.

10. The multi-stage burner according to claim 1, characterized in that: The multi-stage burner body (1) includes a housing (11) covering the annular burner (2), and the housing (11) is provided with a methanol flow channel (12) matching the annular burner (2), and the methanol flow channel (12) is connected to the first fuel pipe (22) corresponding to the peripheral fuel outlet (21).

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