Pressurized oxygen-enriched burner based on adjustable ejector and wall micro-airflow synergistic drag reduction

Abstract

This invention discloses a pressurized oxygen-enriched burner based on adjustable ejector and wall micro-airflow synergistic drag reduction, belonging to the field of burners. It includes a burner body, primary air-coal duct, and oxidant supply system. Its core improvement lies in the inclusion of an ejector anti-clogging device within the primary air-coal duct. This device comprises a Venturi ejector, an adjustable external mechanism for dynamically adjusting the effective flow area at its throat, and a porous fluidized bed bushing embedded in the wall of the downstream easily clogged section. A closed gas chamber connecting to the gas supply pipeline is located on the outside of the porous fluidized bed bushing. This invention generates a controllable negative pressure at the throat through adjustable ejector to "macroscopically draw" coal powder, while simultaneously utilizing the pressure difference to create a "microscopic air cushion" through the porous bed bushing. This synergistic effect solves the technical problems of high coal powder concentration and easy clogging under pressurized oxygen-enriched conditions, improving combustion stability and load regulation capability.

Description

Technical Field

[0001] This invention belongs to the field of burners, and more specifically, relates to a pressurized oxygen-enriched burner that optimizes the pulverized air supply and improves combustion stability based on adjustable ejector and wall micro-airflow synergistic drag reduction technology. Background Technology

[0002] As the global energy structure transitions towards a low-carbon model, carbon neutrality has increasingly become a focus of international attention. According to a report by the Intergovernmental Panel on Climate Change (IPCC), global warming needs to be kept below 1.5°C, posing a severe challenge to the use of traditional fossil fuels. However, fossil fuels such as coal still occupy an important position in my country's and the global energy structure, making low-carbon utilization pathways crucial for achieving carbon neutrality.

[0003] Against this backdrop, oxy-fuel combustion technology has attracted significant attention due to its high efficiency in capturing carbon dioxide, low cost, and ease of large-scale application (suitable for both retrofitting existing power plants and building new ones). Traditional oxy-fuel combustion technology typically operates under atmospheric pressure, but with technological advancements, pressurized oxy-fuel combustion is gradually demonstrating greater potential and represents an important direction for the next generation of efficient, low-pollution coal utilization technologies.

[0004] Because pressurized oxygen-enriched combustion increases the pressure to the MPa level, the volume of the combustion gas is compressed more than ten times, resulting in a corresponding reduction in the burner pipe diameter. This significantly increases the concentration of pulverized coal particles in the pulverized coal feed duct compared to atmospheric pressure combustion, and the flow space is more confined. This makes it very easy for deposits to accumulate and bridge at bends, contraction sections, and other parts, ultimately leading to blockage and seriously affecting the safe and stable operation of the burner.

[0005] However, under pressurized, oxygen-enriched conditions with high pulverized coal concentrations, existing technologies for alleviating pulverized coal blockage struggle to achieve stable and long-term effectiveness. Common practices primarily rely on increasing the primary air velocity or introducing auxiliary airflow at localized locations to enhance pulverized coal carrying capacity or disturb the deposition area. However, under high pressure, these methods often require a significant increase in gas flow rate to be effective. This not only leads to a marked increase in system energy consumption but also exacerbates erosion and wear on pipelines and internal components, limiting both long-term economic efficiency and reliability. Furthermore, as the pulverized coal concentration further increases, the anti-blocking effect of simply increasing flow velocity rapidly diminishes, making it difficult to adapt to changes in actual operating conditions.

[0006] Another approach involves installing purge ports at easily clogged sections such as bends and contractions, intervening in the deposition by introducing gas into the localized area. These measures are typically passive and localized, only offering some relief for existing clogging trends and failing to provide continuous and uniform control over the entire transport flow field. Furthermore, the purge gas volume is often fixed or manually adjusted, making it difficult to adaptively adjust to changes in coal quality, load fluctuations, and other operating conditions, resulting in limited anti-clogging capabilities under high-pressure and high-concentration conditions.

[0007] In addition, existing technologies also employ fixed-structure Venturi ejectors to improve pulverized coal conveying conditions. Although such structures can generate ejection negative pressure to a certain extent, their throat flow area cannot be changed, resulting in a single ejection intensity. When system load, feed rate, or operating pressure changes, the fixed ejection capacity often fails to match these changes, easily leading to insufficient ejection causing pulverized coal retention, or excessive ejection causing unnecessary pressure drop and flow field disturbance, thus affecting combustion stability. Under pressurized oxygen-enriched conditions, this structure, lacking adjustment capabilities, struggles to meet the stable operation requirements across a wide range of operating conditions.

[0008] Therefore, none of the above methods can provide a solution that can proactively adapt to operating conditions and systematically maintain the long-term stability of pulverized coal transportation under high-pressure oxygen-enriched environments. Against this backdrop, developing an internal burner structure that integrates an active, adjustable anti-clogging mechanism has become crucial for advancing pressurized oxygen-enriched combustion technology towards engineering applications. Summary of the Invention

[0009] This invention specifically aims to provide a systematic internal solution for harsh operating conditions involving MPa-level pressure, high pulverized coal concentration, and wide load fluctuations, simultaneously achieving the following objectives: First, addressing the problem of pulverized coal deposition and clogging under high-pressure, oxygen-rich conditions, an adjustable ejector structure is introduced into the primary air-pulverized coal pipeline, coupled with wall micro-airflow drag reduction measures in easily clogged areas, ensuring continuous and adjustable flow support for pulverized coal during transport, thereby reducing the possibility of particle retention and accumulation in localized areas; Second, considering the impact of coal quality changes and load fluctuations on the transport state, the ejector intensity is designed to be adjustable according to operating conditions, enabling the pulverized coal flow state to match changes in system pressure and feed rate, maintaining a relatively uniform and continuous transport state over a wide operating range; Furthermore, while meeting the requirements for anti-clogging and stable transport, the transport adjustment has a certain degree of self-adaptive capability by linking operating parameter monitoring with the adjustable ejector mechanism, while maintaining a high degree of structural integration, facilitating engineering modifications and applications based on existing burners.

[0010] This invention achieves the above objectives through integration, aiming to overcome the key bottleneck in pulverized coal transportation during pressurized oxygen-enriched combustion, and providing core equipment support for its safe, stable, efficient, and flexible engineering applications. To achieve these objectives, this invention is implemented through the following technical solutions:

[0011] This invention proposes a pressurized oxygen-enriched burner that optimizes the coal supply air and improves combustion stability based on adjustable ejector and wall micro-airflow synergistic drag reduction technology. The pressurized oxygen-enriched burner includes a burner body, a primary air-coal system, an oxidant supply system, an adjustable ejector device, and a porous fluidized bushing.

[0012] The primary air-coal system includes a primary air duct for conveying primary air carrying pulverized coal.

[0013] The oxidant supply system includes a secondary air channel and a tertiary air channel. The secondary air channel is used to supply oxidizing gas to the combustion zone, and the tertiary air channel is used to supply cooling and protective gas to the area near the wall of the burner nozzle while simultaneously supplying oxidizing gas.

[0014] The adjustable ejector device is fixedly installed inside the primary air-powder duct, and includes a sealed variable cross-section pipe body, a movable pin assembly, a drive transmission mechanism, a differential speed fine adjustment device, and a high-pressure sealing assembly.

[0015] The sealed variable cross-section tube has a flow channel designed according to the Venturi principle, including a variable throat. The variable throat is provided with a mounting seat arranged coaxially with the tube body;

[0016] The throat design of the described Venturi ejector is adjustable. This is necessary because a fixed throat results in a single ejection intensity, making it difficult to adapt to changing operating conditions. Under high loads or when pulverized coal flowability deteriorates, a fixed ejector may fail to draw in sufficient pulverized coal, while at low loads, excessive throttling pressure drop can lead to unnecessary energy consumption and flow field disturbances. The adjustable throat design of this invention allows the ejection intensity to be flexibly matched to real-time operating conditions (such as coal quality, load, and pipeline pressure), thereby achieving efficient and adaptive anti-clogging control.

[0017] The movable pin assembly includes a tapered pin with a reasonably designed taper, the front end of which is a guide part, the middle part is a sealing part, and the tail end is a connecting part.

[0018] The tapered pin is connected to the drive transmission mechanism via its connecting part. The tapered pin's tapered design aims to continuously and smoothly adjust the throat flow area when the pin moves axially, avoiding pulsation or pressure oscillations in the pulverized coal flow that might be caused by abrupt changes in area, thus maintaining conveying stability. The corresponding differential speed fine-tuning device is designed to meet the requirements of high-precision control of small displacements under high-pressure sealing conditions, ensuring accurate adjustment and sensitive response, preventing system oscillations caused by over-adjustment, thereby achieving fine and stable control of the ejector force.

[0019] The output shaft of the linear drive unit is connected to a transmission screw via a coupling. The transmission screw and a nut fixed at the tail of a tapered pin form a screw-nut pair. The drive transmission mechanism includes a linear drive unit located outside the pipe.

[0020] The differential speed adjustment device is installed in the drive transmission mechanism to achieve precise control of the pin movement speed.

[0021] The porous fluidized bed bushing is embedded in the wall of the primary air-powder duct downstream of the primary air duct in sections prone to blockage (such as elbows and contraction sections).

[0022] The system consisting of the porous fluidized bed bushing and the closed gas chamber differs fundamentally from traditional local high-pressure purging in its anti-clogging mechanism. Instead of injecting a large amount of agitated airflow into the main flow, it utilizes the pressure difference created by the ejector to allow gas to uniformly infiltrate the pipe through micropores at an extremely low velocity (e.g., 0.05-0.2 m / s). The main function of this micro-airflow is to form a stable "air cushion" between the coal powder particles and the pipe wall, significantly reducing the probability of particle adhesion to the wall surface through the wall drag reduction effect, thereby preventing deposition. This "micro-air cushion" works synergistically with the "macro-suction" effect generated by the upstream Venturi ejector: the ejector accelerates the coal powder flow and pushes it towards the center of the pipe, while the downstream wall micro-airflow prevents secondary particle migration and deposition on the wall surface due to uneven velocity distribution, constituting a systematic anti-clogging scheme that combines upstream and downstream synergy and active / passive action.

[0023] As a further preferred embodiment, the cone angle (i.e., the angle between the generatrix of the cone surface and the axis) of the tapered pin ranges from 8° to 25°, and the material is preferably made of a high-temperature resistant and wear-resistant material, and the surface can be precision polished or coated with a low-friction coating.

[0024] Preferably, the differential fine-tuning device includes a harmonic reducer or a planetary gear reducer, which is installed between the linear drive unit and the transmission lead screw, and the movement accuracy can reach ±0.1mm.

[0025] Preferably, the linear drive unit of the drive transmission mechanism is a stepper motor, a servo motor, or a manual mechanical device.

[0026] The closed-loop control system, comprised of the controller and pressure / flow sensors, aims to achieve proactive early warning and intelligent adjustment against blockages. The signals monitored in real-time by the sensors are used to determine the trend of flow resistance changes within the pipeline, identifying potential blockage risks early on, rather than simply displaying status. Based on this, the controller automatically adjusts the adjustable external mechanism, dynamically changing the ejector intensity, thereby intervening before blockages form and maintaining the pulverized coal conveying state within a stable range. This achieves a shift from "passively responding to blockages" to "actively maintaining smooth flow."

[0027] Preferably, the high-pressure sealing assembly adopts two optional schemes: the first is a metal bellows seal, one end of which is welded to the pipe wall and the other end is connected to the sealing part of the pin; the second is a multi-stuffing gland sealing structure, including at least three stuffing glands, each stuffing gland being filled with graphite packing, polytetrafluoroethylene packing and metal spiral wound gasket respectively, and the pre-tightening force is provided by the gland.

[0028] Preferably, the porous fluidized bushing is made of sintered metal powder or fiber, with an average pore size of 10-100 μm, a porosity of 30%-50%, and a permeability in the range of 1-10 Darcy, in order to balance air permeability and structural strength.

[0029] Furthermore, the present invention may also include a controller that automatically controls the action of the adjustable external mechanism based on the feedback signal from the pressure or flow sensor installed on the primary air-powder duct, thereby realizing intelligent closed-loop control for ejector anti-blockage.

[0030] The working principle of this invention is as follows: By designing and installing an adjustable ejector device in a localized area of ​​the primary air duct, a negative pressure zone is formed behind the throat, increasing the rate of decrease in static pressure of the primary air supply and preventing blockage of the primary air. Simultaneously, a porous fluidized bushing made of sintered metal or special ceramic is embedded in the downstream wall of the primary air duct. This porous fluidized bushing is connected to a closed, pressurized protective gas chamber (oxygen-enriched combustion typically uses filtered flue gas or CO2 gas). The pressure drop in the ejector channel creates a pressure difference between the primary air duct and the protective gas chamber. This pressure difference causes a small, low-velocity gas to continuously and uniformly seep out through the porous medium wall of the protective gas chamber. This micro-airflow forms an air cushion layer between the coal powder particles and the primary air duct wall, greatly reducing frictional resistance and preventing coal powder accumulation.

[0031] This invention provides a pressurized oxygen-enriched burner based on adjustable ejector and wall micro-airflow synergistic drag reduction. It possesses the following beneficial effects:

[0032] This invention addresses the problems of high pulverized coal concentration, limited flow space, and easy deposition and blockage in primary air-coal pipelines under pressurized oxygen-enriched combustion conditions. Without significantly increasing system complexity, it achieves simultaneous improvement in pulverized coal conveying stability and burner operational reliability through active control of the pulverized coal conveying flow field.

[0033] In this invention, an adjustable Venturi ejector structure is introduced into the primary air-coal duct, enabling the pulverized coal flow to achieve macroscopic suction and acceleration with controllable intensity during transportation. When the system load, coal quality characteristics, or operating pressure changes, the ejector intensity can be adjusted accordingly, thereby avoiding the problems of insufficient ejection or excessive pressure drop under different operating conditions associated with fixed ejector structures. This effectively improves the overall flow state of high-concentration pulverized coal within the duct.

[0034] Meanwhile, the pressure difference generated by the ejector structure is further used to drive the downstream porous bushing to generate a uniform, low-velocity wall micro-airflow. This micro-airflow does not participate in the mainstream transport but forms a stable air cushion near the inner wall of the pipe, physically isolating the direct contact between the coal powder particles and the pipe wall, thereby significantly reducing the friction and adhesion tendency of particles at the wall surface. In this way, the present invention avoids the increased energy consumption and flow field instability problems caused by traditional high-pressure purging or local disturbances, making the anti-clogging effect more continuous, gentle, and sustainable over a long period of time.

[0035] The aforementioned adjustable ejector and wall micro-airflow are spatially connected and work together in terms of mechanism: the upstream ejector enhances the overall transport capacity of the pulverized coal flow, while the downstream wall drag reduction inhibits particle migration and secondary deposition on the wall. The synergistic effect of the two enables the pulverized coal to pass through the blockage-prone area in a more uniform and stable state under pressurized and oxygen-enriched conditions, thereby effectively reducing the probability of blockage.

[0036] Furthermore, by introducing real-time monitoring of pressure or flow signals and linking it with the adjustable ejector mechanism, this invention transforms anti-clogging regulation from a passive response to active control. When abnormal changes occur in the flow resistance within the pipeline, the system can adjust the ejector intensity in time before blockage forms, intervening in the pulverized coal flow state, reducing fluctuations during operation and the need for manual intervention, which is beneficial for the burner to maintain stable operation over a wide load range.

[0037] From a structural and engineering application perspective, the anti-clogging measures of this invention are all integrated inside the burner. The porous fluidized bushing itself has no moving parts, relying on pressure difference to naturally form a micro-airflow, making its operation simple and reliable. The adjustable external mechanism adopts a sealing and transmission form suitable for high-pressure environments, exhibiting good durability and ease of maintenance. The overall structure is compact, facilitating modification and application on existing burners, and providing a practically feasible equipment solution for the engineering promotion of pressurized oxygen-enriched combustion technology. Attached Figure Description

[0038] Figure 1 It is a pressurized oxygen-enriched burner constructed according to a preferred embodiment of the present invention, based on adjustable ejector and wall micro-airflow synergistic drag reduction.

[0039] Figure 2 yes Figure 1 A cross-sectional view of plane AA.

[0040] Figure 3 yes Figure 1 Schematic diagram of the adjustable ejector device and porous fluidized bushing structure.

[0041] In the diagram: 1. Burner body; 2. Primary air-coal duct; 21. Elbow; 22. Pipe diameter contraction section; 23. Pressure sensor; 24. Flow sensor; 3. Protective gas inlet; 4. Venturi ejector; 5. Adjustable external mechanism; 51. Conical pin; 52. Differential speed fine adjustment device; 53. Linear drive unit; 54. Dynamic sealing assembly; 6. Porous fluidized bed bushing; 7. Sealed gas chamber; 8. Gas supply pipeline; 9. Controller; 10. Gas distributor. Detailed Implementation

[0042] 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.

[0043] like Figures 1 to 3 As shown, the present invention provides a pressurized oxygen-enriched pulverized coal burner, comprising a burner body 1, a primary air-coal duct 2, an oxidant supply system (not fully shown in the figure, but typically includes secondary and tertiary air channels), and a core ejector anti-clogging device. The protective gas inlet 3 is connected to the throat negative pressure zone of the Venturi ejector 4 via a gas distributor 10, allowing a portion of the protective gas to be drawn in as ejector gas.

[0044] The ejector anti-clogging device is integrated within the primary air-coal duct 2. A Venturi ejector 4 is fixedly installed inside the duct 2. During operation, it creates a controllable negative pressure zone at the throat, generating an adjustable macroscopic suction effect on the upstream pulverized coal flow, thus providing active ejection power for the anti-clogging system. The Venturi ejector 4 has an axially movable conical pin 51 at its throat. The axial displacement of the pin allows for continuous and smooth change of the effective flow area at the throat, enabling fine adjustment of the ejection intensity and preventing flow field instability caused by sudden changes in flow area. The tail of the conical pin 51 is connected to an adjustable external mechanism 5 outside the duct via a transmission mechanism. This adjustable external mechanism 5 includes a linear drive unit 53 (e.g., a servo motor), a differential speed fine-tuning device 52 (e.g., a harmonic reducer), and a dynamic sealing assembly 54 (e.g., a metal bellows) to ensure high-pressure sealing. Through the aforementioned structural coordination, control commands can be reliably converted into minute displacements of the conical pin 51, enabling reliable and precise adjustment of the ejector intensity under high-pressure sealing conditions, avoiding over- or under-adjustment. The controller 9 controls the linear drive unit 53, which, after deceleration by the differential speed adjustment device 52, precisely drives the conical pin 51 to move along its axis. This continuously and precisely adjusts the effective flow area of ​​the venturi throat, changing the ejector intensity. By introducing pressure or flow signals into the control loop, the ejector intensity can be automatically adjusted according to the real-time operating status within the pipeline, thus intervening in the coal powder flow state before blockage occurs, improving the system's stability and adaptability. When the pressure value detected by the pressure sensor 23 exceeds the threshold, the linear drive unit 53 is controlled to move the conical pin 51 towards the throat. This method directly links the signal sensing of the operating status with the adjustment action, enabling the anti-blockage adjustment to automatically respond to changes in operating conditions, reducing the need for manual intervention and improving the system's operational stability and reliability.

[0045] In the primary air-coal pipeline 2, when the coal feeding equipment connects to the primary air path, there will be an elbow 21 (due to equipment installation limitations) or a pipe diameter contraction section 22 (such as a tee). A segmented or multi-segment continuous porous fluidized bed bushing 6 is embedded in this bushing. Driven by the pressure difference between the inside and outside of the pipe wall, protective gas can uniformly infiltrate near the inner wall of the pipe at extremely low speed through micropores, forming a stable microscopic air cushion layer on the wall surface. This reduces the probability of direct contact between coal powder particles and the pipe wall, achieving wall drag reduction. This porous fluidized bed bushing 6 is made of sintered stainless steel powder with an average pore size of 50 μm and a porosity of 40%. The porous fluidized bed liner 6 is enclosed by a sealed gas chamber 7, which is connected to a protective gas source (such as pressurized CO2) via a gas supply pipe 8. This gas chamber 7 provides a stable and controllable gas pressure to the porous fluidized bed liner 6, enabling the continuous and uniform generation of micro-airflow, which works in conjunction with the pressure difference formed by the Venturi ejector. The Venturi ejector 4 draws in the upstream primary air-powder flow, which relies on the wall micro-airflow formed by the porous fluidized bed liner 6 to improve downstream flow (powdered coal converges towards the center and does not contact the wall, thus preventing accumulation). Therefore, the downstream porous fluidized bed liner 6 can prevent the primary airflow drawn in by the ejector from accumulating or adhering downstream.

[0046] As a more complete and specific application embodiment, the burner body 1 is axially connected to a primary air inlet (i.e., the inlet section of the primary air-coal duct 2), a pressurized secondary air duct, and a furnace. Following the primary air-coal duct 2, a switching valve, a Venturi ejector 4, and a porous fluidized bed bushing 6 are sequentially installed along the airflow direction. The Venturi ejector 4 is precisely controlled by an external adjustable mechanism 5, which includes a linear drive unit 53 and a differential speed fine-tuning device 52 for precisely driving an internal tapered pin 51.

[0047] The pressurized secondary air ducts are distributed around the burner body 1, and their outlet ends are equipped with swirl vanes to create swirl in the secondary air. A tertiary air duct is also provided outside the secondary air duct to supply cooling and protective air and supplemental oxidizer to the burner nozzle area. In addition, the burner may be equipped with an air supply insulation device connected to the gas supply pipeline 8 to preheat the intake air.

[0048] During the burner start-up phase, an atmospheric pressure gas fuel inlet and an atmospheric pressure air passage for start-up are provided. The atmospheric pressure air passage can be switched via adjustable blades. During the start-up phase, it serves as an air supply passage, and after transitioning to the oxygen-enriched combustion phase, it can be switched to a micro-flow air chamber passage connected to the closed air chamber 7.

[0049] The specific work process is as follows:

[0050] First, initialize the system by closing the valves for the primary, secondary, and tertiary air, and set the adjustable external mechanism 5 to the fully open state to maximize the flow area at the throat of the Venturi ejector 4.

[0051] Switch the switching valve to the position connecting to the atmospheric pressure gas fuel inlet, and simultaneously switch the atmospheric pressure air passage to be connected to atmospheric pressure air. At this time, the system is under atmospheric pressure, and there is no gas leakage in the porous fluidized bushing 6. The mixture of atmospheric pressure gas fuel and air is ignited by the ignition device to preheat the furnace.

[0052] Once the furnace temperature reaches the predetermined value, a fuel switching operation is performed. First, the switching valve is switched to the position connecting the primary air-coal pipeline 2. After the combustion stabilizes, the supply of atmospheric pressure gas fuel is shut off, and a coal-air mixture is introduced into the system to achieve atmospheric pressure air combustion of coal.

[0053] After the pulverized coal is stably combusted, the pressurized secondary and tertiary air channels are gradually opened, and their air source is gradually switched from air to oxygen-enriched gas (oxygen volume concentration controlled within the range of 30%-50%). At the same time, the aforementioned atmospheric air channel is switched to introduce low-speed pressurized CO2. After purging the corresponding pipes, the adjustable blades are adjusted to close the channel. The transition time for this stage is controlled within 10-15 minutes.

[0054] After the oxygen-enriched switching is completed, the entire system is gradually pressurized, with the pressurization rate controlled within 0.1 MPa / min. The target pressure can reach 1.5 MPa according to design requirements. As the system pressure increases, the thermal power and pulverized coal feed rate are increased accordingly.

[0055] During this process, the ejector anti-blocking system automatically engages: the adjustable external mechanism 5, based on the signal from the pressure sensor 23 installed on the primary air-coal duct 2, drives the conical pin 51 inside the Venturi ejector 4 to precisely adjust the throat area, forming a controllable negative pressure that draws in upstream coal powder. Simultaneously, due to the throttling pressure drop generated by the Venturi ejector, the pressure in the downstream primary air-coal duct 2 is lower than the pressure in the closed gas chamber 7. This pressure difference automatically drives gas through the micropores of the porous fluidized bushing 6, continuously and uniformly infiltrating into the pipe. Preferably, the infiltrated gas velocity is controlled within the range of 0.05-0.2 m / s, forming a stable air cushion layer between the coal powder particles and the pipe wall, effectively reducing frictional resistance.

[0056] Combination Figures 1 to 3As shown, when the pressurized oxygen-enriched burner of the present invention is put into operation, the primary air-coal gas flow enters the burner through the primary air-coal pipe 2, and passes sequentially through the Venturi ejector 4 and the porous fluidized bushing 6 area located downstream of it. Under normal operating conditions, the adjustable external mechanism 5 positions the conical pin 51 in an appropriate position, and the Venturi throat forms a flow area that matches the current operating conditions, allowing the primary air-coal gas flow to pass stably under low flow resistance conditions.

[0057] As the coal powder feed rate, system load, or operating pressure changes, the flow state within the primary air-coal powder pipeline 2 also changes accordingly. When the flow resistance tends to increase due to increased coal powder concentration or local flow field unevenness within the pipeline, the pressure sensor 23 or flow sensor 24 installed on the pipeline can promptly detect this change and feed the signal back to the controller 9. The controller then drives the adjustable external mechanism 5 to move the conical pin 51 axially towards the Venturi throat, thereby reducing the effective flow area at the throat. Based on the Venturi effect, the flow velocity at this point increases, creating a stronger negative pressure zone behind the throat, which enhances the suction effect on the upstream primary air-coal powder flow, thus timely guiding and adjusting the coal powder flow state.

[0058] As the aforementioned ejection effect intensifies, the pressure drop in the Venturi throat and its downstream region also increases accordingly, causing the pressure inside the primary air-coal duct 2 to be lower than the gas pressure in the closed gas chamber 7 outside the porous fluidized bushing 6. Driven by this stable pressure difference, the gas in the closed gas chamber 7 continuously infiltrates near the inner wall of the duct through the micropores of the porous fluidized bushing 6 at a low speed and in a uniform manner, forming a continuous micro-flow layer on the duct wall. This micro-flow does not change the mainstream conveying direction, but rather isolates and reduces drag between the coal powder particles and the pipe wall, inhibiting the retention and adhesion of particles at the wall surface.

[0059] Therefore, the enhanced overall transport capacity of the pulverized coal flow by the upstream adjustable ejector and the suppression of particle deposition tendency by the downstream wall micro-airflow naturally form a synergistic relationship during operation. The former improves the flow state of pulverized coal through macroscopic suction, while the latter prevents local deposition by reducing drag at the wall. During the above operation, the adjustable ejector and the wall micro-airflow work together to maintain a relatively stable transport state of the primary air-pulverized coal when passing through areas prone to blockage, thereby reducing the probability of blockage.

[0060] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A pressurized oxygen-enriched burner based on adjustable ejector and wall micro-airflow synergistic drag reduction, comprising a burner body (1), a primary air-coal duct (2) disposed on the body (1), and a protective gas inlet (3), characterized in that, The primary air-powder duct (2) is equipped with an ejector anti-clogging device, which includes: A Venturi ejector (4) is fixedly installed inside the primary air-powder duct (2); An adjustable external mechanism (5) is connected to the Venturi ejector (4) and is used to dynamically adjust the effective flow area of ​​the throat of the Venturi ejector (4). A porous fluidized bushing (6) is embedded in the wall of the downstream section of the primary air-powder duct (2) and the Chinese-made Tully ejector (4) which is prone to blockage. A closed air chamber (7) exists on the other side wall of the porous fluidized bushing (6), enclosing the primary air-powder pipe (2) and the porous fluidized bushing (6), and the closed air chamber (7) is connected to a gas supply pipe (8).

2. The pressurized oxygen-enriched pulverized coal burner according to claim 1, characterized in that, The adjustable external mechanism (5) includes: A tapered pin (51) is provided at the throat of the Venturi ejector (4) with its axis perpendicular to the axis of the primary air-powder duct (2) and axially movable. The differential speed fine adjustment device (52) is fixed outside the primary air-powder pipe (2), and its output end is connected to the conical pin (51); A linear drive unit (53) is disposed outside the primary air-powder duct (2), and its output end is connected to the input end of the differential speed fine adjustment device (52); The dynamic sealing assembly (54) is located on the outside of the wall of the primary air-powder duct (2), covering the Venturi ejector (4) and enclosing the conical pin (51).

3. The pressurized oxygen-enriched pulverized coal burner according to claim 2, characterized in that, The dynamic sealing assembly (54) is a metal bellows seal or a multi-seal packing gland structure, the linear drive unit (53) is a stepper motor, a servo motor or a manual mechanical device; the cone angle of the tapered pin (51) ranges from 8° to 25°.

4. The pressurized oxygen-enriched pulverized coal burner according to claim 1, characterized in that, The porous fluidized bushing (6) is made of sintered metal powder or sintered metal fiber, with an average pore size ranging from 10 μm to 100 μm, a porosity of 30% to 50%, and a permeability in the range of 1-10 Darcy.

5. The pressurized oxygen-enriched pulverized coal burner according to claim 1 or 4, characterized in that, The porous fluidized bushing (6) is at least embedded in the elbow (21) and / or the pipe diameter contraction section (22) and / or the wall of the Venturi ejector (4) of the primary air-powder pipe (2).

6. The pressurized oxygen-enriched pulverized coal burner according to claim 1 or 2, characterized in that, It also includes a controller (9), the signal input terminal of which is communicatively connected to a pressure sensor (23) and / or a flow sensor (24) disposed on the primary air-powder duct (2), and the control output terminal of the controller (9) is electrically connected to the linear drive unit (53) of the adjustable external mechanism (5); The controller (9) is configured to control the linear drive (53) to move the tapered pin (51) toward the throat to enhance the ejection force when the pressure value detected by the pressure sensor (23) exceeds the threshold.

7. The pressurized oxygen-enriched pulverized coal burner according to claim 1, characterized in that, The protective gas inlet (3) is connected to the throat negative pressure zone of the Venturi ejector (4) through a gas distributor (10), so that part of the protective gas is drawn in as the ejector gas.

8. A combustion device, characterized in that, The combustion equipment is equipped with a pressurized oxygen-enriched pulverized coal burner as described in any one of claims 1 to 7.

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