A circumferential stepless adjustable plasma free radical injection ammonia coal combustion device

Abstract

The application relates to the field of combustion technology and pollutant control technology, in particular to a circumferential stepless adjustable plasma free radical injection ammonia coal mixed combustion device.The technical scheme comprises an ammonia coal mixed combustion burner body, a plasma free radical generator system and an online diagnosis control system; the ammonia coal mixed combustion burner body comprises a central primary air channel, an annular ammonia gas channel and a secondary air channel which are sequentially and concentrically arranged along the radial direction from inside to outside; the central primary air channel is arranged in a central primary air shell, an annular flame stabilizer is arranged at the outlet end close to the hearth of the central primary air channel, and a first flue gas backflow area is formed downstream of the annular flame stabilizer.The application realizes efficient and stable ammonia coal mixed combustion through double-position circumferential rotatable plasma free radical injection, stepless adjustable discharge distance and online closed-loop control of flue gas components, significantly improves the ignition performance, burnout rate and working condition adaptability, effectively reduces ammonia escape and NO X emission, and has the advantages of intelligent regulation and industrial application value.

Description

Technical Field

[0001] This invention relates to the fields of combustion technology and pollutant control technology, and in particular to a circumferentially steplessly adjustable plasma free radical injection ammonia-coal co-firing combustion device. Background Technology

[0002] Ammonia, as a zero-carbon fuel, is an important technological approach for existing coal-fired boilers and industrial kilns to achieve low-carbon transformation and reduce carbon emissions through co-firing with pulverized coal. However, ammonia has a high ignition temperature, slow flame propagation speed, and is difficult to mix with solid fuels such as pulverized coal. Direct co-firing of ammonia and coal can easily lead to ignition difficulties, poor combustion stability, low combustion efficiency, and high levels of nitrogen oxides (NOx). X Issues such as increased emissions.

[0003] Traditional burner structures rely solely on flow field organization for fuel mixing, making it difficult to simultaneously achieve ammonia activation, efficient gas-solid two-phase mixing, stable flame combustion, and synergistic control of combustion pollutants. This fails to meet the actual needs of industrial low-NOx, stable, and efficient combustion.

[0004] Current technologies attempt to enhance ammonia-coal co-combustion with plasma assistance, but they generally suffer from drawbacks such as a single plasma injection method, uneven circumferential distribution, and simple control methods. This makes it difficult to achieve uniform distribution of plasma free radicals throughout the burner and precise adjustment of excitation intensity. Furthermore, the lack of online monitoring and closed-loop control of flue gas components at the combustion outlet prevents adaptive optimization of plasma parameters, ammonia-coal ratio, and swirl mixing intensity based on real-time combustion conditions. Consequently, the stability, combustion efficiency, and low-emission performance of ammonia-coal co-combustion remain significantly hampered, limiting the industrial application and promotion of plasma-assisted ammonia-coal co-combustion technology. Therefore, this application proposes a circumferentially steplessly adjustable plasma free radical injection ammonia-coal co-combustion combustion device. Summary of the Invention

[0005] The purpose of this invention is to address the problems in the prior art, such as difficulty in igniting ammonia, uneven mixing, poor combustion stability, and NO... X To address issues such as high emissions, limited plasma-assisted combustion methods, inflexible control, and lack of online closed-loop control, a circumferentially steplessly adjustable plasma free radical injection ammonia-coal co-firing combustion device is proposed.

[0006] The technical solution of the present invention is: a circumferentially steplessly adjustable plasma free radical injection ammonia-coal co-firing combustion device, comprising an ammonia-coal co-firing burner body, a plasma free radical generator system, and an online diagnostic and control system;

[0007] The ammonia-coal co-firing burner body includes a central primary air channel, an annular ammonia channel, and a secondary air channel arranged concentrically from the inside to the outside in a radial direction. The central primary air channel is located inside the central primary air shell, and an annular flame stabilizer is provided at its outlet end near the furnace. A first flue gas recirculation zone is formed downstream of the annular flame stabilizer. The annular ammonia channel is located in the annular space between the central primary air shell and the ammonia fuel shell. An axial ammonia channel is provided on the ammonia fuel shell near the outlet end of the ammonia channel, and a radial ammonia channel is also provided on the central primary air shell. The outlet of the central primary air channel, the outlet of the annular ammonia channel, and the outlet of the secondary air channel together form a premixing zone.

[0008] The plasma radical generator system includes a first-position plasma radical generator and a second-position plasma radical generator;

[0009] The second-position plasma radical generator is disposed on the annular flame stabilizer and includes at least two circumferentially distributed second-position plasma radical generator units; the first-position plasma radical generator is disposed on the ammonia fuel casing and includes at least two circumferentially distributed first-position plasma radical generator units; a large gear is mounted on the ammonia fuel casing, and the large gear meshes with a gear shaft driven by a second drive motor assembly, thereby driving the ammonia fuel casing and the first-position plasma radical generator to rotate circumferentially; the first-position plasma radical generator unit and / or the second-position plasma radical generator unit are plasma radical generators with adjustable discharge distance;

[0010] The online diagnostic and control system includes an online monitoring system and a closed-loop control system. The online monitoring system includes a housing laser emitter and a housing laser receiver symmetrically arranged at the outlet end of the secondary air duct. The optical path formed by the housing laser emitter and housing laser receiver covers the diameter of the burner outlet cross-section, used for real-time online detection of NO in the flue gas. X and NH3 concentration; the closed-loop control system is used to adjust the NO concentration based on the detected NO concentration. X The discharge distance of the adjustable plasma free radical generator, the rotational speed of the second drive motor, and / or the ammonia flow rate of the annular ammonia channel are adjusted in real time based on the NH3 concentration signal.

[0011] Optionally, the axial ammonia channel includes a first axial ammonia and plasma radical injection channel, a second axial ammonia and plasma radical injection channel, and a third axial ammonia and plasma radical injection channel arranged sequentially along the axial direction of the ammonia fuel shell, for injecting ammonia and plasma radicals into the central primary air channel.

[0012] Optionally, the axial ammonia and plasma radical injection channels are all circular holes and distributed in a circumferential ring array. The distribution angle between two adjacent channels is 7.5° to 15°, and the angle between the axial ammonia and plasma radical injection channels and the radial axis is 15° to 30°, which is used to form a clockwise injection stream.

[0013] Optionally, the radial ammonia channels include radial ammonia and plasma radical first injection channel, radial ammonia and plasma radical second injection channel, and radial ammonia and plasma radical third injection channel arranged circumferentially along the central primary air shell for injecting ammonia and plasma radicals into the premixing zone.

[0014] Optionally, the radial ammonia and plasma free radical first injection channel is a rectangular channel, distributed in a clockwise ring array along the circumference, with the distribution angle between two adjacent channels being 15° and the angle with the radial axis being 15°.

[0015] Both the radial-side ammonia and plasma free radical second injection channel and the radial-side ammonia and plasma free radical third injection channel are designed as circular holes, distributed in a circumferential ring array. The distribution angle between two adjacent channels is 7.5°~15°, and the angle with the radial axis is 15°~30°, which is used to form a rotating flow stream with the central primary air channel as the center.

[0016] Optionally, the first position plasma radical generator includes a first position 90° plasma radical generator, a first position 210° plasma radical generator, and a first position 330° plasma radical generator. The first position 90° plasma radical generator, the first position 210° plasma radical generator, and the first position 330° plasma radical generator are arranged counterclockwise at 120° intervals along the circumference of the ammonia fuel shell, and are used to inject plasma radicals into the first flue gas recirculation zone and the central fuel flow.

[0017] Optionally, the second position plasma radical generator includes a second position 30° plasma radical generator, a second position 150° plasma radical generator, and a second position 270° plasma radical generator. The second position 30° plasma radical generator, the second position 150° plasma radical generator, and the second position 270° plasma radical generator are arranged counterclockwise at 120° intervals along the circumference of the annular flame stabilizer, and are used to inject plasma radicals into the premixing zone and the flame zone.

[0018] Optionally, the first position plasma radical generator further includes a discharge distance adjustable plasma radical generator unit; the discharge distance adjustable plasma radical generator unit includes a generator housing, a high voltage electrode, a ground electrode, a high temperature resistant ceramic nozzle, and an electrode distance adjustment mechanism.

[0019] The generator housing can be detachably installed on the ammonia fuel housing or the annular flame stabilizer.

[0020] The high-voltage electrode and the ground electrode are coaxially disposed inside the generator housing, forming an annular discharge gap and a plasma free radical channel between them.

[0021] The high-voltage electrode is externally fitted with an insulating sleeve and swirl blades;

[0022] The high-temperature resistant ceramic nozzle is located at the front end of the generator housing and is connected to the ground electrode.

[0023] Optionally, the electrode distance adjustment mechanism includes a first drive motor assembly, a pinion shaft, and a movable gear;

[0024] The first drive motor is fixed on the generator housing, and its output end is connected to the pinion shaft; the movable gear is connected to the lead screw of the generator housing and meshes with the pinion shaft; the first drive motor drives the pinion shaft to rotate the movable gear, thereby driving the generator housing together with the ground electrode to move axially, so as to realize the real-time continuous adjustment of the discharge distance between the high voltage electrode and the ground electrode.

[0025] Optionally, the operation of the device includes the following steps:

[0026] Step 1: Introduce the primary air-coal powder mixture, ammonia, and secondary air into the central primary air duct, the annular ammonia duct, and the secondary air duct, respectively;

[0027] Step 2: Start the plasma radical generator at the first position and start the second drive motor set to drive the ammonia fuel shell and the plasma radical generator at the first position to rotate at a speed of 1 rpm to 10 rpm, injecting plasma radicals into the first flue gas recirculation zone and the central fuel flow to assist the initial ignition of the ammonia fuel;

[0028] Step 3: Start the second position plasma radical generator to inject plasma radicals into the premixing zone and flame zone to enhance mixing and combustion;

[0029] Step 4: Real-time online detection of NO in the burner outlet flue gas using the laser emitter and receiver on the casing. X Concentration and NH3 concentration;

[0030] Step 5: Based on the detected NO XAnd NH3 concentration, through a closed-loop control system, perform at least one adjustment operation: when NO X When the concentration is higher than the first set threshold, increase the discharge distance of the plasma radical generator unit and / or increase the rotation speed; when the NH3 concentration is higher than the second set threshold, decrease the discharge distance of the plasma radical generator and / or adjust the ammonia flow rate.

[0031] Compared with the prior art, this application includes at least one of the following beneficial technical effects:

[0032] 1. This invention achieves three-dimensional uniform enhanced injection of plasma free radicals: Through a dual-position, circumferentially distributed plasma free radical generator, highly active free radicals are injected from multiple directions and depths into the coal powder flow, ammonia flow, and premixing zone. Combined with a rotatable structure, the mixing uniformity and coverage are improved, which significantly promotes ammonia cracking and early ignition of ammonia fuel.

[0033] 2. This invention achieves real-time and precise control of plasma parameters: by adopting an electrode distance motor-driven adjustment mechanism, the discharge distance can be continuously adjusted according to the combustion conditions, and the plasma energy density, free radical yield and jet momentum can be precisely controlled, thereby improving the device's adaptability to operating conditions and its combustion optimization capabilities.

[0034] 3. This invention achieves online intelligent closed-loop control of combustion status: NO is detected non-contactly in situ via an online laser monitoring device at the burner outlet. X The plasma intensity and fuel-air ratio are dynamically adjusted in real time based on the concentration of unburned NH3 to achieve optimal synergy between combustion efficiency and pollutant emissions.

[0035] 4. This invention achieves efficient mixing of ammonia and coal and stable flame combustion: The rotatable shell combined with the shaft and radial multi-channel nozzles forms a dynamic mixing flow field, which, together with the annular flame stabilizer, constructs a stable flue gas recirculation zone, significantly improving the stability, burnout rate and wide operating condition adaptability of ammonia and coal co-combustion.

[0036] In summary, this invention achieves efficient and stable mixed combustion of ammonia and coal through dual-position circumferentially rotatable plasma radical injection, steplessly adjustable discharge distance, and online closed-loop control of flue gas components. This significantly improves ignition performance, burnout rate, and adaptability to different operating conditions, while effectively reducing ammonia slip and NO emissions. X Emissions control has both intelligent regulation and industrial application value. Attached Figure Description

[0037] Figure 1 This is an axial cross-sectional view of the main body structure of the ammonia-coal co-firing burner of the present invention;

[0038] Figure 2 This is a circumferential arrangement diagram of various plasma radical generators with different arrangement angles proposed in this invention;

[0039] Figure 3 This is an axial cross-sectional view of the plasma free radical generator unit with adjustable discharge distance proposed in this invention;

[0040] Figure 4 This is a schematic diagram of the axial ammonia injection channel arrangement of the present invention;

[0041] Figure 5 This is a schematic diagram of the radial ammonia injection channel and online monitoring system layout of the present invention.

[0042] Reference numerals: 1. Ammonia-coal co-firing burner body; 2. Central primary air channel; 3. Annular ammonia channel; 4. Secondary air channel; 5. First position plasma radical generator; 6. Second position plasma radical generator; 101. Drive motor support plate; 102. Gear shaft; 103. Ammonia fuel inlet; 104. Secondary air inlet; 105. Wear-resistant ring; 106. Secondary air shell; 107. Secondary air swirl blade; 108. Premixing zone; 109. Annular flame stabilizer; 110. Shaft-side ammonia channel; 111. Radial ammonia channel; 112. Ammonia fuel shell; 113. Rolling bearing; 114. Central primary air shell; 115. Large gear; 116. Second drive motor unit; 121. First flue gas recirculation zone; 501. First position 90°, etc. Ion radical generator; 502, First position 210° plasma radical generator; 503, First position 330° plasma radical generator; 601, Second position 30° plasma radical generator; 602, Second position 150° plasma radical generator; 603, Second position 270° plasma radical generator; 504, Generator housing; 505, Insulating sleeve; 506, Swirl blade; 507, High-voltage electrode; 508, Ground electrode; 509, High-temperature resistant ceramic nozzle; 510, Carrier gas path quick interface; 511, Electrical quick interface; 512, First drive motor assembly; 513, Drive motor bracket; 514, Pinion shaft; 515, Movable gear; 516, Plasma radical channel; 517, Plasma radical;

[0043] 801, Shell laser emitter; 901, Shell laser receiver; 1101, Axial-side ammonia and plasma radical first injection channel; 1102, Axial-side ammonia and plasma radical second injection channel; 1103, Axial-side ammonia and plasma radical third injection channel; 1111, Radial-side ammonia and plasma radical first injection channel; 1112, Radial-side ammonia and plasma radical second injection channel; 1113, Radial-side ammonia and plasma radical third injection channel. Detailed Implementation

[0044] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0045] Example

[0046] like Figures 1-5 As shown, the present invention proposes a circumferentially steplessly adjustable plasma free radical injection ammonia-coal co-firing combustion device, which includes an ammonia-coal co-firing burner body 1, a plasma free radical generator system, and an online diagnostic and control system.

[0047] The ammonia-coal co-firing burner body 1 includes a central primary air channel 2, an annular ammonia channel 3, and a secondary air channel 4 arranged concentrically from the inside to the outside in a radial direction. The central primary air channel 2 is located inside the central primary air shell 114, and an annular flame stabilizer 109 is provided at its outlet end near the furnace. A first flue gas recirculation zone 121 is formed downstream of the annular flame stabilizer 109. The annular ammonia channel 3 is located in the annular space between the central primary air shell 114 and the ammonia fuel shell 112. The ammonia fuel shell 112 is provided with an axial ammonia channel 110 near the outlet end of the ammonia channel. The axial ammonia channel 110 includes an axial ammonia and plasma free radical first injection channel 1101, an axial ammonia and plasma free radical second injection channel 1102, and an axial ammonia and plasma free radical third injection channel 1103 arranged sequentially along the axial direction of the ammonia fuel shell 112 for injecting ammonia and plasma free radicals into the central primary air channel 2. The axial ammonia and plasma free radical injection channels are all circular holes and are arranged circumferentially. The ammonia and plasma radical injection channels are arranged in a rectangular array, with an angle of 7.5° to 15° between adjacent channels. The angle between the axial ammonia and plasma radical injection channels and the radial axis is 15° to 30°, forming a clockwise injection stream. The central primary air shell 114 is also provided with a radial ammonia channel 111. The outlets of the central primary air channel 2, the annular ammonia channel 3, and the outlet of the secondary air channel 4 together form a premixing zone 108. The radial ammonia channel 111 includes a first radial ammonia and plasma radical injection channel 1111, a second radial ammonia and plasma radical injection channel 1112, and a third radial ammonia and plasma radical injection channel 1113, which are arranged circumferentially along the central primary air shell 114 to inject ammonia and plasma radicals into the premixing zone 108. The first radial ammonia and plasma radical injection channel 1111 is a rectangular channel, arranged in a clockwise annular array along the circumference, with an angle of 15° between adjacent channels and an angle of 15° with the radial axis.

[0048] Both the radial ammonia and plasma free radical second injection channel 1112 and the radial ammonia and plasma free radical third injection channel 1113 are circular holes, distributed in a circumferential ring array. The distribution angle between two adjacent channels is 7.5°~15°, and the angle with the radial axis is 15°~30°, which is used to form a rotating flow stream with the central primary air channel 2 as the center.

[0049] The plasma radical generator system includes a first-position plasma radical generator 5 and a second-position plasma radical generator 6. The first-position plasma radical generator 5 includes a first-position 90° plasma radical generator 501, a first-position 210° plasma radical generator 502, and a first-position 330° plasma radical generator 503. The first-position 90° plasma radical generator 501, first-position 210° plasma radical generator 502, and first-position 330° plasma radical generator 503 are arranged counterclockwise at 120° intervals along the circumference of the ammonia fuel casing 112, for use in... Plasma radicals are injected into the first flue gas recirculation zone 121 and the central fuel stream; the second position plasma radical generator 6 includes a second position 30° plasma radical generator 601, a second position 150° plasma radical generator 602, and a second position 270° plasma radical generator 603. The second position 30° plasma radical generator 601, the second position 150° plasma radical generator 602, and the second position 270° plasma radical generator 603 are arranged counterclockwise at 120° intervals along the circumference of the annular flame stabilizer 109, and are used to inject plasma radicals into the premixing zone 108 and the flame zone.

[0050] The second-position plasma radical generator 6 is disposed on the annular flame stabilizer 109 and includes at least two second-position plasma radical generator units distributed circumferentially; the first-position plasma radical generator 5 is disposed on the ammonia fuel casing 112 and includes at least two first-position plasma radical generator units distributed circumferentially; a large gear 115 is mounted on the ammonia fuel casing 112, and the large gear 115 meshes with the gear shaft 102 driven by the second drive motor assembly 116, thereby driving the ammonia fuel casing 112 and the first-position plasma radical generator 5 to rotate circumferentially; the first-position plasma radical generator unit and / or the second-position plasma radical generator unit are plasma radical generators with adjustable discharge distance;

[0051] The first position plasma radical generator 5 also includes a discharge distance adjustable plasma radical generator unit; the discharge distance adjustable plasma radical generator unit includes a generator housing 504, a high voltage electrode 507, a ground electrode 508, a high temperature resistant ceramic nozzle 509, and an electrode distance adjustment mechanism.

[0052] The generator housing 504 can be detachably installed on the ammonia fuel housing 112 or the annular flame stabilizer 109;

[0053] The high-voltage electrode 507 and the ground electrode 508 are coaxially disposed inside the generator housing 504, forming an annular discharge gap and a plasma free radical channel 516 between them.

[0054] The high-voltage electrode 507 is externally fitted with an insulating sleeve 505 and a swirl vane 506;

[0055] A high-temperature resistant ceramic nozzle 509 is located at the front end of the generator housing 504 and is connected to the ground electrode 508;

[0056] The electrode distance adjustment mechanism includes a first drive motor assembly 512, a pinion shaft 514, and a movable gear 515;

[0057] The first drive motor assembly 512 is fixed on the generator housing 504, and its output end is connected to the pinion shaft 514. The movable gear 515 is connected to the lead screw of the generator housing 504 and meshes with the pinion shaft 514. The first drive motor assembly 512 drives the pinion shaft 514 to rotate the movable gear 515, thereby driving the generator housing 504 together with the ground electrode 508 to move axially, so as to realize the real-time continuous adjustment of the discharge distance between the high voltage electrode 507 and the ground electrode 508.

[0058] The online diagnostic control system includes an online monitoring system and a closed-loop control system. The online monitoring system includes a housing laser emitter 801 and a housing laser receiver 901 symmetrically arranged at the outlet end of the secondary air duct 4. The optical path formed by the housing laser emitter 801 and the housing laser receiver 901 covers the diameter of the burner outlet cross-section, used for real-time online detection of NO in the flue gas. X and NH3 concentration; the closed-loop control system is used to adjust the NO concentration based on the detected NO levels. X The discharge distance of the adjustable plasma free radical generator, the rotational speed of the second drive motor group 116, and / or the ammonia flow rate of the annular ammonia channel 3 are adjusted in real time based on the NH3 concentration signal.

[0059] Specifically, this embodiment mainly includes an ammonia-coal co-firing burner body 1, a plasma free radical generator system, and an online diagnostic control system. Both the plasma free radical generator system and the online diagnostic control system are arranged on the ammonia-coal co-firing burner body 1. The plasma free radical generator system is used to directionally inject plasma free radical active components according to the flue gas composition detected online, enhancing the reactivity of ammonia, promoting efficient ammonia-coal co-firing, and simultaneously suppressing NO. X The ammonia-coal co-firing burner body 1 is installed on the boiler furnace wall, and is concentrically arranged with a central primary air channel 2, an annular ammonia gas channel 3 and a secondary air channel 4 from the inside to the outside in the radial direction. The central primary air channel 2 is located in the central primary air shell 114, forming a primary air duct for conveying the primary air-coal mixture. The end of the central primary air shell 114 near the furnace is provided with an annular flame stabilizer 109. The central primary air channel 2 is located near the furnace end and forms a first flue gas recirculation zone 121 downstream of the annular flame stabilizer 109. Multiple second-position plasma free radical generator units are evenly arranged circumferentially on the annular flame stabilizer 109. An annular ammonia channel 3 is located in the annular space between the central primary air shell 114 and the ammonia fuel shell 112. The ammonia fuel shell 112 is provided with an axial ammonia channel 110 near the outlet end of the ammonia channel. The central primary air shell 114 is also provided with a radial ammonia channel 111. Multiple first-position plasma free radical generator units are arranged circumferentially on the ammonia fuel shell 112.

[0060] The axial ammonia channel 110 includes an axial ammonia and plasma free radical first injection channel 1101, an axial ammonia and plasma free radical second injection channel 1102, and an axial ammonia and plasma free radical third injection channel 1103. The axial ammonia and plasma free radical injection channels are all circular holes and distributed in a circumferential ring array. The distribution angle between adjacent channels is 7.5°~15°, and the angle between the extension direction of the axial ammonia and plasma free radical injection channel and the radial axis is 15°~30°. The radial ammonia channel 111 includes a first radial ammonia and plasma radical injection channel 1111, a second radial ammonia and plasma radical injection channel 1112, and a third radial ammonia and plasma radical injection channel 1113. The first radial ammonia and plasma radical injection channel 1111 is a rectangular channel, arranged in a clockwise ring array along the circumference, with a distribution angle of 15° between adjacent channels and an angle of 15° with the radial axis. The second radial ammonia and plasma radical injection channels 1112 and the third radial ammonia and plasma radical injection channel 1113 are both circular holes, arranged in a ring array along the circumference, with a distribution angle of 7.5° to 15° between adjacent channels, and an angle of 15° to 30° between the extension direction of the radial ammonia and plasma radical injection channel and the radial axis. A large gear 115 is installed on the ammonia fuel outer shell 112. The large gear 115 meshes with the gear shaft 102 driven by the second drive motor set 116, which can drive the ammonia fuel outer shell 112 and the first position plasma free radical generator 5 on it to generate circumferential rotation. The second drive motor set 116 is installed on the drive motor support plate 101, which is fixed to the central primary air shell 114. The secondary air channel 4 is located in the annular space between the ammonia fuel outer shell 112 and the secondary air shell 106. The secondary air shell 106 is provided with a wear-resistant ring 105, a secondary air inlet 104, and secondary air swirl blades 107. The secondary air shell 106 is symmetrically provided with a shell laser emitting end 801 and a shell laser receiving end 901 near the furnace end. The secondary air channel 4, the central primary air channel 2, and the annular ammonia channel 3 together form a premixing zone 108 near the furnace end.

[0061] When ammonia gas is introduced into the annular ammonia channel 3, part of the ammonia gas and the free radicals generated by plasma excitation are injected clockwise into the central primary air channel 2 along the axial ammonia and plasma free radical first injection channel 1101, axial ammonia and plasma free radical second injection channel 1102 and axial ammonia and plasma free radical third injection channel 1103, achieving preliminary mixing with the coal powder in the central primary air channel 2. Another part of the ammonia gas and the free radicals generated by plasma excitation are injected into the premixing zone 108 along the radial ammonia and plasma free radical first injection channel 1111, radial ammonia and plasma free radical second injection channel 1112 and radial ammonia and plasma free radical third injection channel 1113, forming a clockwise rotating injection stream in the annular region. This stream rotates around the central primary air channel 2, achieving full mixing with the coal powder in the central primary air channel 2 and the secondary air in the secondary air channel 4. The plasma radical generator system includes a first-position plasma radical generator 5 and a second-position plasma radical generator 6. Each generator group contains multiple plasma radical generator units evenly distributed circumferentially, enabling 360° plasma radical coverage injection into the fuel channel from two spatial positions, thereby improving the mixing effect and combustion efficiency of plasma radicals and fuel. The second-position plasma radical generator 6 includes a second-position 30° plasma radical generator 601, a second-position 150° plasma radical generator 602, and a second-position 270° plasma radical generator 603, arranged counterclockwise at 120° intervals circumferentially. The first-position plasma radical generator 5 includes a first-position 90° plasma radical generator 501, a first-position 210° plasma radical generator 502, and a first-position 330° plasma radical generator 503, also arranged counterclockwise at 120° intervals circumferentially.

[0062] The plasma free radical generator unit is a discharge distance adjustable plasma generator, including a generator housing 504, an insulating sleeve 505, a swirling blade 506, a high-voltage electrode 507 and a ground electrode 508 arranged coaxially, and an electrode distance adjustment mechanism. An annular discharge gap is formed between the high-voltage electrode 507 and the ground electrode 508. The high-voltage insulating sleeve 505 and the swirling blade 506 are coaxially sleeved on the outside of the high-voltage electrode 507. A high-temperature resistant ceramic nozzle 509 is provided at the front end of the generator housing 504. The high-temperature resistant ceramic nozzle 509 is connected to the ground electrode 508 to confine the discharge area and realize the directional injection of plasma free radicals. The electrode distance adjustment mechanism includes a first drive motor assembly 512, a pinion shaft 514, and a movable gear 515 connected to the lead screw of the generator housing 504. The first drive motor assembly 512 drives the pinion shaft 514 to rotate the movable gear 515, thereby driving the generator housing 504 together with the internal ground electrode 508 to move axially, realizing real-time continuous adjustment of the discharge distance between the high voltage electrode 507 and the ground electrode 508, thereby controlling the excitation intensity and ejection speed of plasma free radicals.

[0063] The online diagnostic control system includes an online monitoring system and a closed-loop control system. The online monitoring system includes a housing laser emitter 801 and a housing laser receiver 901 symmetrically arranged at the outlet end of the secondary air duct 4. The optical path formed by the housing laser emitter 801 and the housing laser receiver 901 covers the diameter of the burner outlet cross-section, used for real-time online detection of NO in the flue gas. X The closed-loop control system is used to measure NO concentration and NH3 concentration based on the detected NO concentration. X The discharge distance of the adjustable plasma free radical generator, the rotational speed of the second drive motor group 116, and / or the ammonia flow rate of the annular ammonia channel 3 are adjusted in real time based on the NH3 concentration signal.

[0064] This invention also discloses a control method for the above-mentioned circumferentially steplessly adjustable plasma free radical injection ammonia-coal co-firing combustion device, the specific working process of which is as follows:

[0065] First, a mixture of primary air and pulverized coal, ammonia, and secondary air are introduced into the central primary air channel 2, the annular ammonia channel 3, and the secondary air channel 4, respectively. Then, the first-position plasma radical generator 5 is activated, along with the second drive motor unit 116, driving the ammonia fuel casing 112 and the first-position plasma radical generator 5 to rotate at 1-10 rpm, injecting plasma radicals into the first flue gas recirculation zone 121 and the central fuel stream to assist in initial fuel ignition. Next, the second-position plasma radical generator 6 is activated, simultaneously injecting plasma radicals into the premixing zone 108 and the flame zone to further enhance the combustion of the ammonia-coal mixture. Finally, through an online diagnostic control system, the NO in the burner outlet flue gas is detected in real-time using the casing laser emitter 801 and the casing laser receiver 901. X The concentrations of NO and NH3 were determined, and finally, the NO concentration was measured. X The concentrations of NO and NH3 are controlled by a closed-loop control system that executes at least one closed-loop regulation strategy: when NO is detected... X When the concentration is higher than the first set threshold, the discharge distance of the adjustable plasma radical generator unit is increased to reduce the plasma intensity, and / or the speed of the second drive motor unit 116 is increased to enhance fuel mixing; when the NH3 concentration is detected to be higher than the second set threshold, the discharge distance of the adjustable plasma radical generator is decreased to enhance the plasma intensity, thereby promoting ammonia cracking, and / or the ammonia flow rate of the annular ammonia channel 3 is adjusted, ultimately achieving efficient, stable, and low-emission operation of the ammonia-coal co-firing process.

[0066] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A circumferentially steplessly adjustable plasma free radical injection ammonia-coal co-firing combustion device, characterized in that, Includes the ammonia-coal co-firing burner body (1), plasma free radical generator system, and online diagnostic and control system; The ammonia-coal co-firing burner body (1) includes a central primary air channel (2), an annular ammonia channel (3), and a secondary air channel (4) arranged concentrically from the inside to the outside along the radial direction. The central primary air channel (2) is located inside the central primary air shell (114), and an annular flame stabilizer (109) is provided at its outlet end near the furnace. A first flue gas recirculation zone (121) is formed downstream of the annular flame stabilizer (109). The annular ammonia channel (3) is located in the annular space between the central primary air shell (114) and the ammonia fuel shell (112). An axial ammonia channel (110) is provided near the outlet end of the ammonia channel on the ammonia fuel shell (112), and a radial ammonia channel (111) is also provided on the central primary air shell (114). A premixing zone (108) is formed in front of the outlet of the central primary air channel (2), the outlet of the annular ammonia channel (3), and the outlet of the secondary air channel (4). The plasma radical generator system includes a first-position plasma radical generator (5) and a second-position plasma radical generator (6). The second position plasma radical generator (6) is disposed on the annular flame stabilizer (109) and includes at least two second position plasma radical generator units distributed circumferentially; the first position plasma radical generator (5) is disposed on the ammonia fuel shell (112) and includes at least two first position plasma radical generator units distributed circumferentially; a large gear (115) is installed on the ammonia fuel shell (112), and the large gear (115) meshes with the gear shaft (102) driven by the second drive motor group (116), thereby driving the ammonia fuel shell (112) and the first position plasma radical generator (5) to rotate circumferentially; the first position plasma radical generator unit and / or the second position plasma radical generator unit are plasma radical generators with adjustable discharge distance; The online diagnostic control system includes an online monitoring system and a closed-loop control system. The online monitoring system includes a housing laser emitter (801) and a housing laser receiver (901) symmetrically arranged at the outlet end of the secondary air duct (4). The optical path formed by the housing laser emitter (801) and the housing laser receiver (901) covers the diameter of the burner outlet cross-section, and is used for real-time online detection of NO in the flue gas. X and NH3 concentration; the closed-loop control system is used to adjust the NO concentration based on the detected NO concentration. X The discharge distance of the adjustable plasma radical generator, the rotational speed of the second drive motor group (116), and the ammonia flow rate of the annular ammonia channel (3) are adjusted in real time based on the NH3 concentration signal.

2. The ammonia-coal co-firing combustion device with circumferentially steplessly adjustable plasma free radical injection according to claim 1, characterized in that, The axial ammonia channel (110) includes a first axial ammonia and plasma radical injection channel (1101), a second axial ammonia and plasma radical injection channel (1102), and a third axial ammonia and plasma radical injection channel (1103) arranged sequentially along the axial direction of the ammonia fuel shell (112) for injecting ammonia and plasma radicals into the central primary air channel (2).

3. The ammonia-coal co-firing combustion device with circumferentially steplessly adjustable plasma free radical injection according to claim 2, characterized in that, The axial ammonia and plasma radical injection channels are all circular holes and are distributed in a circumferential ring array. The distribution angle between two adjacent channels is 7.5°~15°. The angle between the axial ammonia and plasma radical injection channels and the radial axis is 15°~30°, which is used to form a clockwise injection stream.

4. The ammonia-coal co-firing combustion device with circumferentially steplessly adjustable plasma free radical injection according to claim 1, characterized in that, The radial ammonia channel (111) includes a first radial ammonia and plasma radical injection channel (1111), a second radial ammonia and plasma radical injection channel (1112), and a third radial ammonia and plasma radical injection channel (1113) arranged circumferentially along the central primary air shell (114) for injecting ammonia and plasma radicals into the premixing zone (108).

5. The ammonia-coal co-firing combustion device with circumferentially steplessly adjustable plasma free radical injection according to claim 4, characterized in that, The radial ammonia and plasma free radical first injection channel (1111) is a rectangular channel, distributed in a clockwise ring array along the circumference, with the distribution angle between two adjacent channels being 15° and the angle with the radial axis being 15°. The radial ammonia and plasma free radical second injection channel (1112) and the radial ammonia and plasma free radical third injection channel (1113) are both set as circular holes and distributed in a circumferential ring array. The distribution angle between two adjacent channels is 7.5°~15°, and the angle with the radial axis is 15°~30°, which is used to form a rotating stream with the central primary air channel (2) as the center.

6. The ammonia-coal co-firing combustion device with circumferentially steplessly adjustable plasma free radical injection according to claim 1, characterized in that, The first position plasma radical generator (5) includes a first position 90° plasma radical generator (501), a first position 210° plasma radical generator (502), and a first position 330° plasma radical generator (503). The first position 90° plasma radical generator (501), the first position 210° plasma radical generator (502), and the first position 330° plasma radical generator (503) are arranged counterclockwise at 120° intervals along the circumference of the ammonia fuel shell (112) to inject plasma radicals into the first flue gas recirculation zone (121) and the central fuel flow.

7. The ammonia-coal co-firing combustion device with circumferentially steplessly adjustable plasma free radical injection according to claim 1, characterized in that, The second position plasma radical generator (6) includes a second position 30° plasma radical generator (601), a second position 150° plasma radical generator (602), and a second position 270° plasma radical generator (603). The second position 30° plasma radical generator (601), the second position 150° plasma radical generator (602), and the second position 270° plasma radical generator (603) are arranged counterclockwise at 120° intervals along the circumference of the annular flame stabilizer (109) to inject plasma radicals into the premixed zone (108) and the flame zone.

8. The ammonia-coal co-firing combustion device with circumferentially steplessly adjustable plasma free radical injection according to claim 1, characterized in that, The first position plasma radical generator (5) further includes a discharge distance adjustable plasma radical generator unit; the discharge distance adjustable plasma radical generator unit includes a generator housing (504), a high voltage electrode (507), a ground electrode (508), a high temperature resistant ceramic nozzle (509), and an electrode distance adjustment mechanism. The generator housing (504) can be detachably installed on the ammonia fuel housing (112) or the annular flame stabilizer (109); The high-voltage electrode (507) and the ground electrode (508) are coaxially disposed inside the generator housing (504), forming an annular discharge gap and a plasma free radical channel (516) between them. The high-voltage electrode (507) is externally fitted with an insulating sleeve (505) and a swirl vane (506). The high-temperature resistant ceramic nozzle (509) is located at the front end of the generator housing (504) and is connected to the ground electrode (508).

9. The ammonia-coal co-firing combustion device with circumferentially steplessly adjustable plasma free radical injection according to claim 8, characterized in that, The electrode distance adjustment mechanism includes a first drive motor assembly (512), a pinion shaft (514), and a movable gear (515). The first drive motor assembly (512) is fixed on the generator housing (504), and its output end is connected to the pinion shaft (514); the movable gear (515) is connected to the lead screw of the generator housing (504) and meshes with the pinion shaft (514); the first drive motor assembly (512) drives the pinion shaft (514) to rotate the movable gear (515), thereby driving the generator housing (504) and the ground electrode (508) to move axially, so as to realize the real-time continuous adjustment of the discharge distance between the high voltage electrode (507) and the ground electrode (508).

10. The ammonia-coal co-firing combustion device with circumferentially steplessly adjustable plasma free radical injection according to claim 1, characterized in that, The working process of the device includes the following steps: Step 1: Introduce a mixture of primary air and pulverized coal, ammonia, and secondary air into the central primary air channel (2), the annular ammonia channel (3), and the secondary air channel (4), respectively. Step 2: Start the first position plasma radical generator (5) and start the second drive motor group (116) to drive the ammonia fuel shell (112) and the first position plasma radical generator (5) to rotate at a speed of 1 rpm to 10 rpm, injecting plasma radicals into the first flue gas recirculation zone (121) and the central fuel flow to assist the initial ammonia fuel ignition; Step 3: Start the second position plasma radical generator (6) to inject plasma radicals into the premixing zone (108) and the flame zone to enhance the mixing and combustion; Step 4: Real-time online detection of NO in the burner outlet flue gas via the housing laser emitter (801) and housing laser receiver (901). X Concentration and NH3 concentration; Step 5: Based on the detected NO X And NH3 concentration, through a closed-loop control system, perform at least one adjustment operation: when NO X When the concentration is higher than the first set threshold, increase the discharge distance of the plasma radical generator unit and / or increase the rotation speed; when the NH3 concentration is higher than the second set threshold, decrease the discharge distance of the plasma radical generator and / or adjust the ammonia flow rate.

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