Middle-tail end double-control integrated efficient clean pulverized coal combustion system

Abstract

The invention discloses a middle-tail end double-control integrated efficient clean pulverized coal combustion system. The system comprises a furnace body, an air supply mechanism, an air quantity angle adjusting mechanism, a combustion chamber, a combustion ring body and a pulverized coal supply pipeline. The combustion ring body comprises a fixed ring body, a guide plate, a plasma generator, a sound wave oscillator assembly and an atomization ring body, and during work, the middle section combustion chamber achieves pulverized coal primary mixing ignition through a combustion stabilizing piece; the tail end combustion ring body firstly decelerates unburnt pulverized coal flue gas and forms vortex retention, then guides pulverized coal to gather towards the axis to form a high-concentration reaction area, synchronously injects micro-mist to permeate the pulverized coal to break coke inertia, then realizes surface and internal double-point activation of the pulverized coal through plasmas, and cooperates with sound wave to strengthen reaction and inhibit coking. The pulverized coal burn-off rate under the low load of the system exceeds 95%, the NOX emission is reduced by more than 30%, and the system is suitable for power station boilers, industrial kilns and other scenes.

Description

Technical Field

[0001] This invention relates to the field of combustion technology, and in particular to a high-efficiency and clean pulverized coal combustion system with integrated mid- and end-stage dual control. Background Technology

[0002] Pulverized coal combustion systems are a core component of energy equipment such as power plant boilers and industrial kilns. Existing systems mostly adopt a segmented design of air supply, combustion, and terminal. Although they can achieve basic combustion functions, the problem of inefficient handling of unburned pulverized coal in the middle and terminal is particularly prominent under low load conditions, becoming a core bottleneck restricting the system's energy efficiency and operational stability.

[0003] When operating at low loads (e.g., boiler load < 50%), the primary air volume output by the front-end air supply mechanism decreases, and the heat release from the combustion chamber is reduced, causing the flue gas temperature entering the middle and end areas to drop to 550~700℃, below the critical ignition temperature of pulverized coal and coke. Furthermore, unburned pulverized coal carried in the flue gas, especially fine powder with a particle size of 20~50μm, is easily dispersed due to flow velocity fluctuations. Existing systems often employ a single air vent or a simple flow guide design for the middle and end areas: secondary air is only supplied through the vent, but due to airflow dispersion, the pulverized coal cannot be gathered to the active area. Ultimately, unburned pulverized coal is discharged with the flue gas, resulting in a combustion rate of only 65%~75%. This not only wastes energy but also causes pulverized coal to adhere to the middle and end components, forming coke and requiring frequent shutdowns for cleaning, severely impacting the system's continuous operation cycle.

[0004] Existing technologies have not yet formed an integrated solution that can adapt to low-load conditions and achieve efficient combustion of pulverized coal in the middle and end stages. There is an urgent need to solve the core problem of difficult handling of unburned pulverized coal under low load through structural innovation. Summary of the Invention

[0005] (a) Technical problems to be solved To address the shortcomings of existing technologies, the present invention aims to provide a mid-to-end dual-control integrated high-efficiency and clean pulverized coal combustion system, which solves the problems existing in the prior art.

[0006] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a mid-to-end dual-control integrated high-efficiency clean pulverized coal combustion system, comprising a furnace body, an air supply mechanism disposed on the left side of the furnace body, an air volume angle adjustment mechanism disposed inside the furnace body, and the air volume angle adjustment mechanism being located in the air outlet section of the air supply mechanism; a combustion chamber disposed in the middle section of the furnace body, a combustion ring disposed in the end section of the furnace body, and a pulverized coal supply pipe penetrating through the inner side of the furnace body; Preferably, the combustion ring body includes a fixed ring body, the fixed ring body has an annular cavity inside, and the inner edge of the fixed ring body has multiple inclined channels communicating with the annular cavity along the axial direction; Preferably, the inner edge of the fixed ring is provided with a guide plate, a plasma generator and an acoustic oscillator assembly, wherein the plasma generator includes multiple sets of plasma discharge electrodes, which are uniformly arranged along the circumferential direction on the inner edge of the fixed ring.

[0007] Preferably, the guide plate is located on the inner edge of the fixed ring and downstream of the plasma discharge electrode. The longitudinal section of the guide plate is a tapered structure that gradually narrows along the combustion direction. The upper edge of the guide plate is provided with a central flow stabilizing plate that extends horizontally towards the furnace axis. The guide plate and the central flow stabilizing plate together form an L-shaped flow-gathering structure.

[0008] Preferably, the acoustic oscillator assembly is located on the inner edge of the fixed ring, and the axis of the acoustic oscillator assembly's acoustic emission port forms a non-90° angle with the surface of the guide plate.

[0009] Preferably, the multi-layer inclined channel includes a lower layer obstruction channel and an upper layer spiral air channel; the axis of the lower layer obstruction channel makes an angle of 15°-20° with the axis of the burner, and its extension direction is opposite to the flue gas flow direction; the axis of the upper layer spiral air channel makes an angle of 30°-45° with the axis of the burner, and is spirally distributed along the circumferential direction of the fixed ring.

[0010] Preferably, the plasma discharge electrodes are arranged in a one-to-one correspondence with the upper spiral air channels, and the plasma discharge electrodes are located in the outlet area of ​​the upper spiral air channels.

[0011] Preferably, the acoustic oscillator assembly and the plasma discharge electrode are arranged alternately in the circumferential direction of the fixed ring, and the lower end of the fixed ring is connected to a second air inlet.

[0012] Preferably, the atomizing ring is sleeved inside the fixed ring and located upstream of the acoustic oscillator assembly along the flue gas flow direction. The inner edge of the atomizing ring is provided with a plurality of atomizing nozzles, and the outlet direction of the atomizing nozzles faces the front end face of the guide plate, for injecting micro-mist into the airflow.

[0013] Preferably, the airflow angle adjustment mechanism includes an adjustment chamber, wherein an active air guide plate and a driven air guide plate are symmetrically hinged inside the adjustment chamber along its central axis, and a V-shaped plate is fixed in the middle section of the adjustment chamber; an adjustment motor is provided on the outside of the adjustment chamber, the adjustment motor is drivenly connected to the active air guide plate, and a transmission rod is provided between the active air guide plate and the driven air guide plate.

[0014] Preferably, the combustion chamber includes a chamber body, and a gas chamber is provided at one end of the chamber body near the air supply mechanism. A combustion stabilizer is fixed on the inner edge of the chamber body. Multiple sets of L-shaped secondary air ducts extend outward from the inner edge of the gas chamber, and an air inlet pipe is connected to the bottom of the gas chamber.

[0015] Preferably, the combustion stabilizer is a circular plate structure with two sets of inclined guide plates arranged on it: one set of inclined guide plates is distributed circumferentially along the outer edge of the combustion stabilizer, and the other set of inclined guide plates is distributed circumferentially along the middle of the combustion stabilizer with the center as the reference; corresponding to the air outlet position of each set of secondary air ducts, two rings of through holes are opened on the combustion stabilizer in a ring array.

[0016] Preferably, the outlet end of the pulverized coal supply pipeline is fixed to the combustion stabilizer plate.

[0017] (III) Beneficial Effects The purpose of this invention is to provide a mid-to-end dual-control integrated high-efficiency clean pulverized coal combustion system, which effectively solves the problem of difficult handling of unburned pulverized coal under low load conditions. The airflow angle adjustment mechanism can precisely control the airflow direction and distribution of primary air through the linkage adjustment of active and driven air guides. It works in conjunction with the combustion chamber's stabilizing plate and secondary air duct. The inclined guide plate of the stabilizing plate guides the airflow to form a rotating flow field, and the secondary air duct accurately delivers supplementary air into the unburned coal powder area. The two work together to achieve the initial uniform mixing of coal powder and air and stable main combustion, laying the foundation for low unburned coal powder in the middle and end treatment.

[0018] The combustion ring serves as the core intensifying unit. Its lower layer of the fixed ring's obstruction channels creates vortices by reverse jet injection, significantly extending the residence time of unburned pulverized coal. The upper layer of spiral air channels injects swirling airflow, enhancing the turbulent mixing of pulverized coal and air. The guide plate, with its conical structure, gathers the flue gas and pulverized coal towards the axis, forming a local recirculation zone in conjunction with the central flow stabilizer. This increases the pulverized coal concentration to the critical reaction value while maintaining regional temperature stability through the recirculating high-temperature flue gas. The atomizing ring, fitted inside the fixed ring, injects 5-10 μm micro-mist into the high-concentration pulverized coal zone at this stage. The micro-mist penetrates along the pores of the pulverized coal to the core, weakening the carbon-carbon bonds of the internal coke through polar molecules and forming a steam cavity that connects the inside and outside, opening a channel for subsequent reactions. After the plasma discharge electrodes are superimposed, the active particles can be precisely applied to the high-concentration area, not only dissociating the surface micro-mist to generate OH・ for low-temperature ignition, but also penetrating deep into the steam chamber to generate H・ to activate the inert coke; while the acoustic oscillator, which is arranged alternately with the electrodes, further enhances particle collision and mixing and prolongs the action time of the active particles through high-frequency sound waves. At the same time, it works in conjunction with the wettability of the micro-mist and uses mechanical vibration to suppress coking of the guide plate.

[0019] These interconnected components enable the system to maintain a pulverized coal combustion rate of ≥95% even under low load conditions, and NO x Emissions are reduced by more than 20%, the ash removal cycle is extended to 6 months, and the air volume angle can be adjusted to adapt to different loads, taking into account efficient combustion, low pollution and long-term stable operation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall system of a mid-to-end dual-control integrated high-efficiency clean pulverized coal combustion system according to the present invention; Figure 2 This is a cross-sectional view of the overall high-efficiency and clean pulverized coal combustion system with integrated mid-end and end-stage dual control according to the present invention. Figure 3 This is a schematic diagram of the air volume angle adjustment mechanism in a mid-to-end dual-control integrated high-efficiency clean pulverized coal combustion system of the present invention; Figure 4 This is a schematic diagram of the combustion chamber in a mid-to-end dual-control integrated high-efficiency clean pulverized coal combustion system of the present invention; Figure 5 This is a schematic diagram of a combustion stabilizer plate in a mid-to-end dual-control integrated high-efficiency clean pulverized coal combustion system of the present invention; Figure 6 This is a schematic diagram of the combustion ring in a mid-to-end dual-control integrated high-efficiency clean pulverized coal combustion system of the present invention; Figure 7 This is a cross-sectional view of the combustion ring in a mid-to-end dual-control integrated high-efficiency clean pulverized coal combustion system of the present invention; Figure 8 for Figure 7 An enlarged view of point A of the combustion ring in a mid-terminal dual-control integrated high-efficiency and clean pulverized coal combustion system of the present invention; Figure 9 This is a half-sectional view of the guide plate in a mid-to-end dual-control integrated high-efficiency clean pulverized coal combustion system of the present invention; In the diagram: 1-furnace body, 2-air supply mechanism, 3-air volume angle adjustment mechanism, 4-combustion chamber, 5-combustion ring, 6-pulverized coal supply pipe, 31-adjustment chamber, 32-active guide vane, 33-driven guide vane, 34-V-shaped plate, 35-adjustment motor, 36-transmission rod, 41-chamber body, 42-gas chamber, 43-fire stabilizer plate, 44-secondary air duct, 45-inlet pipe, 431-inclined guide... Plate, 432-through hole, 51-fixed ring, 511-annular cavity, 512-multi-layer inclined channel, 5121-lower layer obstruction channel, 5122-upper layer spiral air channel, 52-guide plate, 521-central flow stabilizer, 53-plasma generator, 531-plasma discharge electrode, 54-acoustic oscillator assembly, 55-atomizing ring, 551-atomizing nozzle, 56-second air inlet. Detailed Implementation

[0021] The following will refer to the appendix in the examples of this invention. Figures 1-9 The technical solutions in the present invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] This invention provides a technical solution: a mid-to-end dual-control integrated high-efficiency clean pulverized coal combustion system, such as... Figure 1 As shown, the furnace body 1 has the following core structure and connection relationships: First, the furnace body and overall layout: Furnace body 1 is a horizontally arranged cylindrical body, which is divided into an air supply section, a combustion section and an end enhancement section along the flue gas flow direction: the left air supply section is equipped with an air supply mechanism 2 and an air volume angle adjustment mechanism 3, the middle combustion section is equipped with a combustion chamber 4, and the end enhancement section is equipped with a combustion ring 5; the pulverized coal supply pipe 6 runs through the inside of furnace body 1, and its outlet end extends into the inside of the combustion chamber 4, which is used to accurately deliver pulverized coal to the combustion area.

[0023] The air supply mechanism 2 is fixed to the left end plate of the furnace body 1, including a centrifugal fan and an air supply duct. The fan outputs ambient temperature air with a pressure of 0.3~0.6MPa, which is connected to the air volume angle adjustment mechanism 3 through the air supply duct to provide initial combustion air for the combustion system.

[0024] The air volume angle adjustment mechanism 3 is located inside the air supply section of the furnace body 1, in the air outlet section of the air supply mechanism 2, and is used to dynamically adjust the air inlet direction and air volume distribution. Its specific structure includes: The regulating chamber 31 is a cylindrical cavity, coaxially arranged with the furnace body 1. Its left end is connected to the air outlet pipe of the air supply mechanism 2, and its right end is connected to the combustion chamber 4. The air guide plate assembly includes an active air guide plate 32 and a driven air guide plate 33, which are symmetrically hinged along the central axis of the regulating chamber 31. The active air guide plate 32 and the driven air guide plate 33 are linked by a transmission rod 36 to form a symmetrical opening and closing structure. An regulating motor 35 is fixed on the outside of the regulating chamber 31, and its output shaft is connected to the active air guide plate 32 through a connecting rod, which can drive the air guide plate to rotate around the hinge axis by an angle of 0° to 60°. A V-shaped plate 34 is fixed in the middle section of the regulating chamber 31, with its tip facing the direction of the incoming airflow. It can divide the airflow into two streams, which are guided to the active air guide plate 32 and the driven air guide plate 33 respectively, thereby enhancing the stability of the regulation.

[0025] By adjusting the rotation of the air guide plate driven by motor 35, the air inlet angle can be continuously adjusted: when the angle between the air guide plate and the axis increases, the airflow deflects towards the inner wall of the furnace body 1, enhancing mixing in the edge area; when the angle decreases, the airflow converges towards the axis, strengthening combustion in the central area. At the same time, in conjunction with the frequency conversion control of the air supply mechanism 2, the air volume and angle can be adjusted in a coordinated manner to adapt to different load conditions.

[0026] Combustion chamber 4 is the expansion area in the middle section of furnace body 1, and is the core place for the initial combustion of pulverized coal. The structure includes: the main body of the chamber 41 is used to form an expanded combustion space and reduce the airflow velocity to prolong the combustion time; The air chamber 42 is arranged in a ring at one end of the main body 41 of the chamber near the air supply mechanism 2. It is connected to secondary air through the air inlet pipe 45 with an air pressure of 0.2~0.4MPa to provide supplementary air for combustion. The secondary air duct 44 consists of multiple sets of "L"-shaped ducts. One end of the duct is connected to the inner edge of the air chamber 42, and the other end extends into the main body of the chamber 41. The air outlet faces downstream of the combustion area and is at an angle of 30° with the axis, which can accurately deliver secondary air into the unburned coal powder concentration area. The flame stabilizer plate 43 is a circular plate structure fixed in the middle of the inner edge of the chamber body 41. It is used to stabilize the flame shape and enhance mixing. It is provided with an inclined guide plate 431 and a through hole 432. The inclined guide plate 431 consists of two sets of annularly distributed inclined guide plates, with the outer edge set and the middle set arranged alternately. The guide plate and the plane of the flame stabilizer plate 43 form an angle of 45°, which can guide the airflow to form a rotating flow field. The through hole 432 corresponds to two ring array holes at the outlet of the secondary air duct 44, so that the secondary air and coal powder are evenly mixed and then pass through the flame stabilizer plate 43 into the downstream.

[0027] The combustion ring 5 is a reinforced burnout structure at the end of the furnace body 1, and is the core component for achieving dual control burnout at the middle and end points, including: The fixed ring 51 is a hollow annular structure with an annular cavity 511 inside. Secondary air is introduced to its lower end through a second air inlet 56. Its inner wall has multiple layers of inclined channels 512 along the axial direction, communicating with the annular cavity 511, specifically including: The lower layer of obstruction channels 5121 can be 2 to 3 layers, with the axis of the channel making an angle of 15° to 20° with the axis of the furnace body 1. The extension direction is arranged in the opposite direction to the flue gas flow direction, which can obstruct the flow of flue gas and prolong the residence time. The upper spiral air channel 5122 can have 3 to 4 layers, with the axis of the channel making an angle of 30° to 45° with the axis of the furnace body 1. It is distributed in a spiral shape along the fixed ring 51, so that the ejected secondary air forms a spiral vortex and enhances mixing. The guide plate 52 is fixed to the inner edge of the fixed ring 51 and is located downstream of the plasma discharge electrode 531. Its longitudinal section is a tapered structure that gradually narrows along the combustion direction. Its upper edge is provided with a central flow stabilizing plate 521 that extends horizontally towards the furnace axis. The two form an L-shaped flow gathering structure, which can gather flue gas and pulverized coal towards the axis. At the same time, a local reflux zone is formed below the flow stabilizing plate to improve the reaction efficiency. The plasma generator 53 includes multiple sets of plasma discharge electrodes 531, which are uniformly arranged circumferentially along the inner edge of the fixed ring 51, corresponding to the upper spiral air channel 5122 and located in its outlet area; the electrodes are made of tungsten copper alloy and connected to a 10~20kHz high-frequency power supply, which can generate low-temperature plasma with a temperature of <500℃, and reduce the ignition temperature of coal powder through active particles such as O・ and OH・. The acoustic oscillator assembly 54 is arranged circumferentially along the inner edge of the fixed ring 51 and is staggered with the plasma discharge electrode 531 to avoid interference; the axis of its acoustic emission port is at an angle of 30°~60° with the surface of the guide plate 52, and the operating frequency is 15~30kHz. It can enhance particle mixing, prolong the action time of active particles, and suppress coking of the guide plate 52 through high-frequency acoustic waves.

[0028] The atomizing ring 55 is made of stainless steel and is fitted inside the fixed ring 51, located upstream of the acoustic oscillator assembly 54 along the flue gas flow direction. Its position design ensures that the micro-mist can be pre-mixed with the airflow and coal powder before entering the plasma interaction zone. Multiple atomizing nozzles 551 are arranged circumferentially on the inner edge of the atomizing ring 55, and the outlet direction of the atomizing nozzles 551 faces the front end face of the guide plate 52, so that the micro-mist can be effectively collected by the guide plate 2 with the airflow.

[0029] The atomizing nozzle 551 has an orifice diameter of 0.5-2 mm, and its axis forms an angle of 15°-30° with the radial direction of the fixed ring 51. It can atomize external steam source, 80-100℃ saturated steam, into micro-droplets of 5-10 μm, with the micro-mist injection volume being 0.5%-2% of the secondary air volume. The micro-mist dissociates into H・ and OH・ free radicals in the high-energy plasma field, which synergistically enhance the oxidation of coal powder with the plasma's own active particles, while achieving uniform distribution across the entire cross-section through acoustic oscillation.

[0030] The pulverized coal supply pipe 6 runs through the side wall of the furnace body 1, and its outlet end is fixed in the central area of ​​the combustion stabilizer plate 43. The pulverized coal is transported to the combustion chamber 4 by a spiral feeder, and then ignited and burned after being mixed with the primary air and secondary air.

[0031] The working principle is specifically divided into the following stages: Phase 1: Pulverized Coal Conveying and Initial Mixing and Ignition Powdered coal is precisely delivered to the central area of ​​the stabilizing plate 43 in the combustion chamber 4 via the powdered coal supply pipe 6. Simultaneously, the air supply mechanism 2 delivers primary air to the airflow angle adjustment mechanism 3. The adjusting motor 35 drives the active guide plate 32 to rotate, which in turn drives the driven guide plate 33 to adjust its angle synchronously via the transmission rod 36. Combined with the diversion effect of the V-shaped plate 34, the primary air forms a directional airflow with a wind speed of 6-10 m / s, which is suitable for the volatile matter of the coal type. It mixes with the powdered coal above the stabilizing plate 43 to form a uniform gas-powder mixture. Under the action of the two sets of inclined guide plates 431 of the stabilizing plate 43, the gas-powder mixture forms a swirling flow with a swirling intensity of 0.2-0.3. At the same time, the air chamber 42 injects secondary air into the swirling core area through the L-shaped secondary air pipe 44 and the through hole 432, accounting for 40%-50% of the total secondary air volume. This ensures that the local powdered coal concentration reaches the critical combustion value of 40-80 g / m³, completing the initial ignition. High volatile coal types ignite by their own volatile matter, while low volatile coal types are preheated by subsequent plasma assistance.

[0032] Second stage: Mid-stage combustion After ignition, the gas-powder mixture enters the middle section of the combustion chamber 4 and completes basic combustion under the action of the swirling field and continuous secondary air supply: the through hole 432 of the stabilizing plate 43 continuously supplies secondary air to avoid incomplete combustion caused by local oxygen deficiency. At the same time, the inclined guide plate 431 suppresses the airflow deviation and ensures that the temperature field in the furnace is uniformly maintained at 1200-1400℃. During this stage, about 70%-80% of the pulverized coal is burned. The generated high-temperature flue gas, with a temperature of 1000-1200℃, carries unburned pulverized coal, mostly coarse powder with a particle size >20μm. The internal coke is not completely oxidized and flows to the combustion ring 5 at the end of the furnace body 1, entering the core strengthening stage.

[0033] Phase 3: Dual-control reinforcement at the end of the combustion annulus Combustion ring 5 addresses the issues of deep combustion and pollution control of unburned pulverized coal under low load through the following steps, with each component's function and process closely integrated: 1. Flue gas retention: Unburned pulverized coal enters the fixed ring 51 area of ​​the combustion ring 5 along with the flue gas. Secondary air is injected into the annular cavity 511 of the fixed ring 51 through the second air inlet 56, accounting for 30%-40% of the total secondary air volume. Some of the secondary air is injected in reverse through the lower blocking channel 5121. The axis of the lower blocking channel 5121 is at an angle of 15°-20° with the axis of the burner. The injection direction is opposite to the flue gas flow direction. The reverse airflow forms momentum opposition with the mainstream flue gas, reducing the flue gas velocity from 8-12m / s to 5-7m / s. The opposing airflow forms a stable vortex field at the outlet of the channel, which causes unburned coal powder to be retained in the vortex. The residence time is extended from the traditional 2-3 seconds to 4-5 seconds, avoiding the problem of "unburned coal powder being discharged" caused by excessively fast flow rate at low load.

[0034] 2. Pulverized coal agglomeration: The decelerated flue gas flows naturally into the guide plate 52 area on the inner edge of the fixed ring 51. The guide plate 52 achieves precise agglomeration of pulverized coal through structural design: the longitudinal section of the guide plate 52 is a tapered structure that gradually narrows along the combustion direction. The wall constraint is used to radially compress the flue gas, causing unburned pulverized coal to gather towards the center of the furnace body, forming a high-concentration reaction zone with a concentration of 60-120 g / m³, which far exceeds the critical concentration for combustion and can meet the low-temperature reaction requirements under low load. The central stabilizing plate 521 at the upper edge of the guide plate 52 forms a local reflux zone, which entrains the already burned 600-650℃ high-temperature flue gas to preheat the accumulated coal powder, raising the coal powder temperature by 50-80℃, initially reducing the ignition difficulty of low volatile coal types, and laying the temperature foundation for subsequent activation reactions.

[0035] 3. Micro-mist infiltration pretreatment: While the pulverized coal is coalescing, the atomizing ring 55 is simultaneously activated to inject micro-mist into the high-concentration reaction zone, achieving synergistic effects of coal coalescing and infiltration. The atomizing ring 55 is fitted inside the fixed ring 51. The atomizing nozzle 551 on the inner edge of the ring atomizes saturated steam at 80-100℃ into micro-droplets of 5-10μm. The micro-droplet injection volume is 0.5%-2% of the secondary air volume. The micro-droplet size is much smaller than the pore diameter of coal powder (20-100μm) and can quickly penetrate into the core of coal powder particles with the airflow. The polar water molecules containing -OH groups in the micro-mist adsorb onto the carbon-carbon bond surface of the coke inside the coal powder, reducing the carbon-carbon bond energy from 347 kJ / mol to below 290 kJ / mol and weakening the inertness of the coke. At the same time, the micro-mist that penetrates to the core forms an "internal steam cavity" at high temperature, avoiding the problem of pores being blocked by CO2 in traditional combustion and opening up channels for subsequent active particles to enter the interior.

[0036] 4. Dual-point activation by plasma: After the micro-mist penetration is completed, the plasma discharge electrode 531 of the plasma generator 53 is activated, achieving dual ignition of the coal powder surface and interior through low-temperature plasma: the plasma discharge electrode 531 is uniformly arranged circumferentially along the inner edge of the fixed ring 51. After connecting the 10-20kHz high-frequency high-voltage power supply, low-temperature plasma is generated in the high-concentration reaction zone, with an electron temperature of 1-10eV and a gas temperature of <500℃; the high-energy electrons in the plasma first dissociate the micro-mist on the surface of the coal powder, generating a concentration of 10¹ 5 -10¹ 6 With OH radicals per cm³, its oxidizing activity is 5 times that of ordinary oxygen. It can rapidly break through the carbon layer on the surface of pulverized coal at a low temperature of 550℃ to achieve surface ignition. At the same time, high-energy electrons indirectly act on the micro-mist in the steam chamber inside the pulverized coal, generating H• active particles with a particle size of only 0.1nm. H• penetrates deep into the particle core along the channels opened by the micro-mist, directly attacking the weakened carbon-carbon bonds and activating the internal inert coke. The reaction formula is: C + H• → CH•, which completely breaks the traditional combustion's fragmented state of "the surface burns brightly, but the inside is not completely burned".

[0037] 5. Acoustic Wave Cyclic Enhancement: Simultaneously with plasma activation, the acoustic wave oscillator component 54 is activated, achieving a dual effect of "reaction enhancement - anti-coking" through high-frequency acoustic waves: The acoustic oscillator assembly 54 and the plasma discharge electrode 531 are arranged alternately in the ring of the fixed ring 51, emitting high-frequency acoustic waves of 15-30kHz and 120-150dB. The compression and sparsity waves of the acoustic waves continuously impact the CO2 gas film on the surface of the coal powder, causing it to break and recombine continuously, avoiding the gas film from hindering the replenishment of active particles, and ensuring that the surface reaction is continuous and efficient. Sound waves induce micro-convection inside the coal powder particles, driving the CO generated by the internal reaction to migrate to the surface, where it reacts with OH・ to generate CO2. At the same time, excess O・ and other active particles on the surface are pumped into the interior, forming a "active particle replenishment - intermediate product discharge" cycle system, which enhances the synergy between surface and internal reactions. In addition, the sound waves drive the surface of the guide plate 52 to generate a micro-amplitude vibration of 5-10μm. Combined with the micro-mist reducing the wettability contact angle of the coal powder from 90° to below 60°, the adhesion between the coal powder and the wall is weakened, and the coking rate is reduced from 0.5mm / day to below 0.1mm / day, thus solving the problem of frequent coking under low load.

[0038] 6. Multi-stage cyclic burnout: The upper spiral air channel 5122 of the fixed ring 51 injects spiral airflow, which carries the unburned coal powder into the cyclic enhancement process: The axis of the upper spiral air channel 5122 is at an angle of 30°-45° with the axis of the burner. The injected secondary air forms a swirling field with a swirling intensity of 0.3-0.5. The centrifugal force generated by the swirling and the radial pressure gradient work together to re-entrain the unburned fine coal powder with a particle size <50μm into the high-concentration reaction zone of the guide plate 52. Ultimately, the temperature of the thoroughly combusted flue gas is 1000-1100℃, and the NO content is... x When the concentration is ≤150mg / m³, a small amount of ash is discharged from the combustion ring 5 and enters the subsequent waste heat recovery and dust removal system to complete the entire combustion process.

[0039] 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 mid-to-end dual-control integrated high-efficiency clean pulverized coal combustion system, comprising a furnace body (1), characterized in that, An air supply mechanism (2) is provided on the left side of the furnace body (1), and an air volume angle adjustment mechanism (3) is provided inside the furnace body (1), with the air volume angle adjustment mechanism (3) located in the air outlet section of the air supply mechanism (2); a combustion chamber (4) is provided in the middle section of the furnace body (1), a combustion ring (5) is provided in the end section of the furnace body (1), and a pulverized coal supply pipe (6) is provided through the inner side of the furnace body (1). The combustion ring (5) includes a fixed ring (51), the fixed ring (51) has an annular cavity (511) inside, and the inner edge of the fixed ring (51) has a multi-layered inclined channel (512) communicating with the annular cavity (511) along the axial direction. The inner edge of the fixed ring (51) is provided with a guide plate (52), a plasma generator (53), an acoustic oscillator assembly (54) and an atomizing ring (55). The plasma generator (53) includes multiple sets of plasma discharge electrodes (531), which are uniformly arranged along the circumferential direction on the inner edge of the fixed ring (51).

2. The mid-to-end dual-control integrated high-efficiency clean pulverized coal combustion system according to claim 1, characterized in that, The guide plate (52) is located on the inner edge of the fixed ring (51) and downstream of the plasma discharge electrode (531). The longitudinal section of the guide plate (52) is a tapered structure that gradually narrows along the combustion direction. The upper edge of the guide plate (52) is provided with a central flow stabilizer (521) that extends horizontally towards the furnace axis. The guide plate (52) and the central flow stabilizer (521) together form a flow-gathering structure with an L-shaped cross section.

3. The integrated high-efficiency clean pulverized coal combustion system with mid-to-end dual control as described in claim 1, characterized in that, The acoustic oscillator assembly (54) is located on the inner edge of the fixed ring (51), and the axis of the acoustic oscillator assembly (54) and the surface of the guide plate (52) form an angle other than 90°.

4. The integrated high-efficiency clean pulverized coal combustion system with mid-to-end dual control as described in claim 1, characterized in that, The multi-layer inclined channel (512) includes a lower layer obstruction channel (5121) and an upper layer spiral air channel (5122); the axis of the lower layer obstruction channel (5121) is at an angle of 15°-20° with the axis of the burner, and its extension direction is opposite to the flue gas flow direction; the axis of the upper layer spiral air channel (5122) is at an angle of 30°-45° with the axis of the burner, and is spirally distributed along the circumferential direction of the fixed ring (51).

5. The integrated high-efficiency clean pulverized coal combustion system with mid-to-end dual control as described in claim 2, characterized in that, The plasma discharge electrode (531) is arranged in a one-to-one correspondence with the upper spiral air channel (5122), and the plasma discharge electrode (531) is located in the outlet area of ​​the upper spiral air channel (5122).

6. The mid-to-end dual-control integrated high-efficiency clean pulverized coal combustion system according to claim 1, characterized in that, The acoustic oscillator assembly (54) and the plasma discharge electrode (531) are arranged alternately in the circumferential direction of the fixed ring (51), and the lower end of the fixed ring (51) is connected to a second air inlet (56).

7. The integrated high-efficiency clean pulverized coal combustion system with mid-to-end dual control as described in claim 1, characterized in that, The atomizing ring (55) is sleeved inside the fixed ring (51) and located upstream of the acoustic oscillator assembly (54) along the flue gas flow direction. Multiple atomizing nozzles (551) are arranged circumferentially on the inner edge of the atomizing ring (55). The outlet direction of the atomizing nozzles (551) faces the front end face of the guide plate (52) and is used to inject micro-mist into the airflow.

8. The integrated high-efficiency clean pulverized coal combustion system with mid-to-end dual control as described in claim 1, characterized in that, The airflow angle adjustment mechanism (3) includes an adjustment chamber (31). An active air guide plate (32) and a driven air guide plate (33) are symmetrically hinged inside the adjustment chamber (31) along its central axis. A V-shaped plate (34) is fixed in the middle section of the adjustment chamber (31). An adjustment motor (35) is provided on the outside of the adjustment chamber (31). The adjustment motor (35) is connected to the active air guide plate (32) in a transmission connection. A transmission rod (36) is provided between the active air guide plate (32) and the driven air guide plate (33).

9. The integrated high-efficiency clean pulverized coal combustion system with mid-to-end dual control according to claim 1, characterized in that, The combustion chamber (4) includes a chamber body (41), and a gas chamber (42) is provided at one end of the chamber body (41) near the air supply mechanism (2). A flame stabilizer plate (43) is fixed on the inner edge of the chamber body (41). Multiple sets of "L"-shaped secondary air ducts (44) extend outward from the inner edge of the gas chamber (42), and an air inlet pipe (45) is connected to the bottom of the gas chamber (42).

10. The mid-to-end dual-control integrated high-efficiency clean pulverized coal combustion system according to claim 9, characterized in that, The combustion stabilizer plate (43) is a circular plate structure with two sets of inclined guide plates (431) arranged on it: one set of inclined guide plates (431) is distributed circumferentially along the outer edge of the combustion stabilizer plate (43), and the other set of inclined guide plates (431) is distributed circumferentially along the middle of the combustion stabilizer plate (43) with the center as the reference; corresponding to the air outlet position of each set of secondary air ducts (44), the combustion stabilizer plate (43) has two rings of through holes (432) arranged in a ring array.

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