Direct-current burner and burning system capable of separating coal powder from thick coal powder and thin coal powder and achieving large-angle reverse blowing of ammonia jet flow

Abstract

The invention belongs to the technical field of clean combustion, and particularly relates to a pulverized coal dense-thin separation and ammonia gas jet flow large-angle reverse blowing direct-current burner and a combustion system, and the direct-current burner comprises an ammonia gas channel, a burner channel and a pulverized coal dense-thin separator; the pulverized coal dense-thin separator is arranged in the combustor channel; the output end of the combustor channel is a thick-thin primary air nozzle, and a separator is arranged in the middle of the thick-thin primary air nozzle; an included angle is formed between the axis of the concentrated-phase primary air back-blowing nozzle and the axis of the combustor channel; the ammonia gas channel is arranged on the side edge of the combustor channel and is arranged close to one side of the concentrated-phase primary air back-blowing nozzle; the output end of the ammonia gas channel is an ammonia gas back-blowing nozzle which forms an included angle with the axis of the combustor channel; the included angle between the ammonia gas back-blowing nozzle and the axis of the combustor channel is larger than the included angle between the axis of the concentrated-phase primary air back-blowing nozzle and the axis of the combustor channel. Compared with the prior art, the problem that a large amount of NOx is easily generated during ammonia-doped combustion of pulverized coal is solved. According to the scheme, ammonia combustion is converted into hydrogen combustion, and high combustion efficiency and environmental protection performance are both considered.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of clean combustion, and particularly relates to a coal powder dense-thin separation and ammonia jet large-angle backblowing straight-flow combustor and combustion system. BACKGROUND

[0002] With the increasingly serious global climate change problem, carbon emission reduction has become an important goal in the energy field. As one of the main ways of global energy supply, the carbon emission of coal-fired power generation accounts for a major share of global energy combustion emissions. In order to achieve green and low carbon, low-carbon transformation of coal-fired boilers is imperative. Ammonia, as a zero-carbon fuel, is considered as one of the important choices for low-carbon transformation of coal-fired boilers due to its high volumetric energy density and easy storage and transportation characteristics, and the existing liquid ammonia storage and transportation infrastructure is perfect, and the transformation cost is low. However, ammonia coal combustion technology still faces many challenges in application. Fuel NOx is easily generated during ammonia combustion, and under the traditional injection mode, the NOx emission is very high, which requires significant increase in additional denitration equipment and operation cost.

[0003] The most important application of coal powder mixed with ammonia combustion is to realize it in the most common four-corner tangential combustion mode of current power station boilers. The core of the traditional four-corner tangential combustion mode is to symmetrically arrange multiple layers of coal powder burners (straight-flow combustors) at the four corners of the furnace, so that the primary air (a mixture of coal powder and air) and the secondary air are injected into the furnace at a specific angle to form a strong turbulent flame rotating around the center imaginary circle. The imaginary tangential circle of each air is usually injected in the same direction and angle. This rotating airflow not only prolongs the residence time of coal particles in the furnace, promoting complete combustion, but also stabilizes the ignition process through high-temperature flue gas backflow. Coal powder mixed with ammonia directly mixes ammonia in the primary air, or separately designs ammonia injection ports and injection ports of primary and secondary air in the same direction of the imaginary tangential circle of the jet into the furnace in the usual straight-flow combustor group. Most of the ammonia will directly contact with the air in the secondary air and mix with oxygen to participate in combustion, which will greatly increase the generation of NOx.

[0004] CN101074775A discloses a dense-phase backblowing multi-stage NOx combustion method, but this scheme mainly solves the nitrogen oxides generated by coal combustion; and in the case that coal combustion has already generated a lot of nitrogen oxides, ammonia gas which is easy to burn to generate nitrogen oxides will not be further added. In addition, existing technologies such as CN117628495A and CN113654038A are only for dense-thin separation of coal powder gas flow.

[0005] CN118816207A discloses a low-NOx combustor for decoupled mixing of staged ammonia and pulverized coal, in which scheme, the pulverized coal and ammonia gas are preheated and pyrolyzed by an electric heating assembly, and the generation of nitrogen oxides is inhibited by changing the gas flow composition and the contact time of ammonia gas with secondary air. However, this scheme fails to fully utilize the combustion environment of the furnace itself, and requires additional electric heating equipment for heating, resulting in high energy demand and high cost of the scheme. SUMMARY

[0006] Studies have shown that ammonia gas will decompose into nitrogen and hydrogen under high-temperature and oxygen-deficient conditions. If most of the ammonia gas can be made to enter a high-temperature and micro-oxygen / zero-oxygen environment for decomposition in the early stage of entering the furnace, and the decomposed hydrogen is then mixed with oxygen to convert into hydrogen combustion mode, the amount of NOx generated can be greatly inhibited. At the same time, in combination with the design of rotating flame and staged air distribution (such as delayed secondary air mixing) for the whole furnace, the oxygen concentration in the local high-temperature zone can be effectively reduced; further combined with the overfire air technology, the overall oxygen deficiency degree of the combustor area can be further controlled. Furthermore, by using a specific pulverized coal and ammonia mixing combustor, the degree of ammonia injection into the high-temperature and oxygen-deficient decomposition zone in the furnace can be significantly improved.

[0007] The purpose of the present application is to solve at least one of the above problems by providing a straight-flow combustor with coal powder concentration and dilution separation and ammonia gas jet large-angle back-blowing and a combustion system to solve the problem of easy generation of NOx in the prior art of pulverized coal and ammonia mixing combustion, and the need for additional heating equipment in the existing treatment method, which cannot fully utilize the heat of the combustor itself. The straight-flow combustor of the present scheme has high stable combustion of coal powder and zero-carbon characteristics of ammonia fuel, realizes conversion of ammonia combustion to hydrogen combustion, and has high combustion efficiency and environmental protection performance, which is a key technology to ensure low-carbon modification of coal-fired boilers.

[0008] The purpose of the present application is achieved by the following technical solutions: The present application discloses a straight-flow combustor with coal powder concentration and dilution separation and ammonia gas jet large-angle back-blowing, comprising an ammonia gas channel, a combustor channel and a coal powder concentration and dilution separator. The coal powder concentration and dilution separator is arranged inside the combustor channel, and the concentration and dilution separation of the primary air is realized by utilizing the inertia difference between the coal powder and the gas flow in the primary air. The output end of the combustor channel is a concentration and dilution primary air nozzle, a partition body is arranged in the middle of the concentration and dilution primary air nozzle, so that the concentration and dilution primary air nozzle is divided into a concentrated primary air back-blowing nozzle and a dilute primary air nozzle which are not connected to each other, for respectively spraying the concentrated primary air and the dilute primary air after concentration and dilution separation; an included angle is arranged between the axis of the concentrated primary air back-blowing nozzle and the axis of the combustor channel, so that the concentrated primary air back-blowing nozzle is arranged towards the upstream direction of the flame, and the concentrated primary air entering the high-temperature area in the center of the furnace is controlled. The ammonia gas passage is arranged at the side of the burner passage, and is arranged close to the side of the thick-phase primary air back-blowing nozzle; the output end of the ammonia gas passage is an ammonia gas back-blowing nozzle, and an included angle is arranged between the ammonia gas back-blowing nozzle and the axis of the burner passage, so that the ammonia gas back-blowing nozzle is arranged towards the upstream direction of the flame, and the high-temperature oxygen-deficient area of the ammonia gas entering the furnace is controlled. The included angle between the ammonia gas back-blowing nozzle and the axis of the burner passage is greater than the included angle between the axis of the thick-phase primary air back-blowing nozzle and the axis of the burner passage.

[0009] Preferably, the pulverized coal thick-thin separator comprises an impact block and a partition plate. The impact block is arranged at the position close to the input end in the burner passage, and is arranged on the side wall on the side of the dilute-phase primary air nozzle; the impact block is arranged as an inclined surface on the side of the airflow. The partition plate is arranged at the position close to the output end in the burner passage, and is connected to one end of the partition body.

[0010] Preferably, the input end of the burner passage is provided with a connecting component, and the connecting component comprises a connecting passage and a connecting flange. One end of the connecting passage is connected with the burner passage. The connecting flange is connected with the other end of the connecting passage.

[0011] Preferably, the thick-thin primary air nozzle further comprises a perimeter air nozzle. The perimeter air nozzle is arranged around the edge of the thick-thin primary air nozzle, and the perimeter air nozzle is not opened on the side close to the ammonia gas back-blowing nozzle, forming a U-shaped or C-shaped structure.

[0012] Preferably, the first side wall of the thick-phase primary air back-blowing nozzle, which is parallel to the partition body, is an inclined surface, and the first side wall is arranged towards the direction away from the axis of the burner passage. The second side wall of the dilute-phase primary air nozzle, which is parallel to the partition body, is a plane, and the second side wall is arranged parallel to the axis of the burner passage. The partition body is a wedge-shaped partition blunt body; the surface of the partition body on the side of the thick-phase primary air back-blowing nozzle is an inclined surface, and is arranged parallel to the first side wall of the nozzle; the surface of the partition body on the side of the dilute-phase primary air nozzle is a plane, and is arranged parallel to the second side wall of the nozzle.

[0013] Preferably, the included angle between the axis of the thick-phase primary air back-blowing nozzle and the axis of the burner passage is 10-20°, and the included angle between the ammonia gas back-blowing nozzle and the axis of the burner passage is 15-25°.

[0014] Preferably, the ammonia channel comprises an ammonia connecting pipe and an ammonia distribution box. The ammonia distribution box is connected with the ammonia backflushing nozzle through the ammonia connecting pipes.

[0015] Preferably, the input end of the ammonia channel is provided with a connecting pipe head.

[0016] Preferably, the thick and thin primary air nozzle is movably connected with the burner channel through a nozzle adjusting device, for adjusting the height of the primary air jetted out of the thick and thin primary air nozzle.

[0017] The second aspect of the present application discloses a coal powder thick and thin separation and ammonia jet large-angle backflushing combustion system, comprising a furnace and the once-through burner as claimed in any one of the above. The once-through burner is arranged at four corners of the furnace, forming a four-corner tangential circle combustion mode. The thick-phase primary air penetrates into the main rotating tangential circle fire ring and deeply enters the high-temperature area in the center of the furnace under the action of backflushing, so as to burn away from the wall surface. The ammonia reverse jet mixes with the high-temperature fire ring of the primary air jet tail of the upstream once-through burner and the backflow high-temperature flue gas after entering the furnace.

[0018] The working principle of the present application is as follows: The thick-phase primary air with high coal powder concentration can penetrate into the main rotating tangential circle fire ring and deeply enter the high-temperature area in the center of the furnace under the action of backflushing, so as to burn away from the wall surface, effectively preventing wall surface slagging and high-temperature corrosion. The large-angle backflushing ammonia jet direction design and high-flow-rate jet into the furnace can strengthen the ammonia large-angle reverse jet into the furnace, and then quickly mix with the high-temperature fire ring of the primary air jet tail of the upstream burner and the backflow high-temperature flue gas, so as to promote the thermal cracking of ammonia into hydrogen, inhibit the generation of NOx in the combustion mode of the later hydrogen, and realize the high-efficiency mixed combustion of a large proportion of mixed ammonia and coal powder.

[0019] Compared with the prior art, the present application has the following beneficial effects: The present application mainly aims at the problem that the coal powder mixed ammonia combustion in power station boilers easily produces a large amount of NOx, which greatly increases the NOx emission concentration and cannot meet the existing emission standard. Therefore, the present application proposes a coal powder mixed ammonia once-through burner based on coal powder thick and thin separation and ammonia jet large-angle backflushing, which solves the problem of high NOx emission of the existing mixed ammonia combustion burner.

[0020] The direct-flow combustor is an innovative combustion equipment oriented to low-carbon transformation, and the core thereof is to form a strong turbulent disturbance and a local backflow area by inversely injecting ammonia gas into a coal powder combustion main gas flow at a high momentum and a large inclination angle. The design utilizes the kinetic energy of the ammonia gas jet to tear the coal powder flame front, strengthens the mixing of the ammonia gas jet with the upstream high-temperature fire ring and the backflow high-temperature flue gas after entering the furnace, and the high-temperature flue gas mixing provides a heat source for ammonia gas cracking and stable combustion, significantly promotes the decomposition of most ammonia fuel into hydrogen, thereby greatly improving the ignition performance and providing conditions for reducing the generation of NOx in the later combustion. The combustor has high stable combustion of coal powder and zero-carbon characteristics of ammonia fuel, realizes conversion of ammonia combustion to hydrogen combustion, and has high combustion efficiency and environmental protection performance, which is a key technology to ensure low-carbon transformation of coal-fired boilers.

[0021] The present application realizes stable combustion of coal powder and efficient and clean combustion of ammonia gas through the synergistic effect of coal powder concentration and dilution separation and ammonia gas large-angle reverse blowing jet, effectively solves the problem of high NOx emission in traditional ammonia mixing combustion, and is suitable for low-carbon transformation of power station boilers. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a structural schematic view of the direct-flow combustor; Figure 2 It is a structural schematic view of the thick and thin primary air nozzle; Figure 3 It is a schematic view of the upper view structure section of the direct-flow combustor; Figure 4 It is a schematic view of the jet trajectory into the furnace in the horizontal section of the combustion system; In the figure: 1-thick and thin primary air nozzle, 101-peripheral air nozzle, 102-thick phase primary air reverse blowing nozzle, 103-dilute phase primary air nozzle, 104-separation body, 105-nozzle second side wall, 106-nozzle first side wall; 2-ammonia gas channel, 201-ammonia gas connecting pipeline, 202-ammonia gas distribution box; 3-ammonia gas reverse blowing nozzle; 4-combustor channel; 5-connection component, 501-connection channel, 502-connection flange; 6-coal powder concentration and dilution separator, 601-impingement block, 602-separation plate; 7-connection pipe head; 10-dilute phase primary air coal powder jet; 20-reverse blowing thick phase primary air coal powder jet; 30-reverse blowing ammonia gas jet. DETAILED DESCRIPTION

[0023] The present application will be described in detail below in combination with the drawings and specific embodiments, the embodiments are implemented on the premise of the technical scheme of the present application, and detailed implementation modes and specific operation processes are given, but the protection scope of the present application is not limited to the following embodiments.

[0024] Example 1 A type of direct-flow burner with pulverized coal concentration separation and ammonia jet backflushing at a large angle, such as... Figures 1-4 As shown, it includes ammonia gas passage 2, burner passage 4, and pulverized coal concentration separator 6; The coal powder concentration separator 6 is installed inside the burner channel 4 and uses the inertial difference between coal powder and airflow in the primary air to achieve concentration separation of the primary air. The output end of the burner channel 4 is a rich-lean primary air nozzle 1. A separator 104 is provided in the middle of the rich-lean primary air nozzle 1 to separate the rich-lean primary air nozzle 1 into a rich phase primary air backflush nozzle 102 and a dilute phase primary air nozzle 103 that are not connected to each other, so as to spray out the rich phase primary air and dilute phase primary air that have been separated. The axis of the rich phase primary air backflush nozzle 102 is set at an angle with the axis of the burner channel 4, so that the rich phase primary air backflush nozzle 102 is set towards the upstream direction of the flame, and the rich phase primary air is controlled to enter the high temperature region in the center of the furnace. The ammonia passage 2 is located on the side of the burner passage 4, and the ammonia passage 2 is located on the side close to the dense phase primary air backflush nozzle 102; the output end of the ammonia passage 2 is an ammonia backflush nozzle 3, and the ammonia backflush nozzle 3 is set at an angle with the axis of the burner passage 4, so that the ammonia backflush nozzle 3 is set towards the upstream direction of the flame, thereby controlling the ammonia to enter the high temperature and oxygen-deficient area of ​​the furnace. The angle between the ammonia backflush nozzle 3 and the axis of the burner channel 4 is greater than the angle between the axis of the dense primary air backflush nozzle 102 and the axis of the burner channel 4.

[0025] More specifically, in this embodiment: like Figure 1 As shown, the DC burner includes: a rich and dilute primary air nozzle 1, an ammonia channel 2, an ammonia backflush nozzle 3, a burner channel 4, a connecting component 5, and a pulverized coal rich and dilute separator 6. The rich and dilute primary air nozzle 1 is located at the burner outlet (output end) and is connected to the burner channel 4. The burner channel 4 inlet (input end) is connected to the connecting component 5, which is the primary air inlet of the DC burner. The pulverized coal rich and dilute separator 6 is located inside the burner channel 4, dividing the primary air into rich-phase primary air and dilute-phase primary air. The ammonia channel 2 is located on the side of the burner channel 4 near the rich-phase primary air, and the ammonia channel 2 outlet (output end) is the ammonia backflush nozzle 3.

[0026] like Figure 2 As shown, the concentrated and dilute primary air nozzle 1 specifically includes: a perimeter air nozzle 101, a concentrated primary air backflush nozzle 102, a dilute primary air nozzle 103, a separator 104, and a second sidewall 105 and a first sidewall 106 of the nozzle. Among them, [the following is a partial translation of the original text, which is not directly related to the nozzle description: "taken as..."] Figure 1 , 2The direction is shown: the dense phase primary air back-blowing nozzle 102 is located at the right part of the dense and thin primary air nozzle 1 in the horizontal direction (the direction of the nozzle), close to the ammonia back-blowing nozzle 3; the dilute phase primary air nozzle 103 is located at the left part of the dense and thin primary air nozzle 1 in the horizontal direction (the direction of the nozzle), and the perimeter air nozzle 101 is arranged outside the dense and thin primary air nozzle 1, and the side close to the ammonia back-blowing nozzle 3 is not provided with the perimeter air nozzle 101.

[0027] The dense phase primary air back-blowing nozzle 102 and the dilute phase primary air nozzle 103 are separated by the partition body 104, forming a "day" type structure. The partition body 104 is a wedge-shaped partition body, which not only plays a role of separating the dense primary air and the dilute primary air, but also plays a role of back-blowing and guiding the flow of the dense primary air. The partition body 104 is arranged along the axis direction of the burner channel 4, so that the two sides thereof pass through the dilute phase coal powder gas flow and the back-blowing dense coal powder gas flow respectively, so as to ensure the independence of each jet to be sprayed into the furnace. The thickness of the partition body 104 is designed according to the gas flow velocity and flow, so as to ensure the strength and stability of the partition device.

[0028] In the partition body 104, the wall surface on the side toward the dilute phase primary air nozzle 103 is parallel to the mounting line of the burner channel 4, that is, the axis of the burner channel 4, and the wall surface is also parallel to the second side wall 105 (the left wall surface of the burner channel 4) in the dilute phase primary air nozzle 103, so that the dilute phase primary air flow can be sprayed into the furnace horizontally and form a forward tangential rotating gas flow; the wall surface on the side toward the dense phase primary air back-blowing nozzle 102 is arranged at an angle of 10°-20° deviated from the burner mounting line, so that the partition body 104 forms a wedge-shaped structure (the thin end part thereof faces the inside of the burner channel 4), and the wall surface is also parallel to the first side wall 106 (the right wall surface of the burner channel 4) in the dense phase primary air back-blowing nozzle 102, that is, the first side wall 106 is deflected at the same angle toward the upstream direction of the tangential rotating flame in the furnace, so that the dense phase primary air flow is sprayed into the inside of the furnace in the form of back-blowing and reversely, and far away from the wall surface (the water-cooled wall surface).

[0029] The input end of the burner channel 4 is the inlet connecting part 5, and the connecting part 5 includes a connecting channel 501 and a connecting flange 502. The connecting channel 501 is the primary air and coal powder inlet of the burner, one end of which is connected with the primary air and coal powder pipeline of the outlet of the coal mill through the connecting flange 502, and the other end is connected with the burner channel 4.

[0030] The primary air injection ports (including the dense phase primary air backflow injection port 102 and the dilute phase primary air injection port 103) are also movably connected to the burner channel 4 through the injection port adjusting device, which can swing up and down by 15° to adjust the flame center height in the furnace. In order to realize the adjustment of the primary air injection port, the primary air injection port is not rigidly connected to the burner channel 4 or as a whole, but is connected by a horizontal pin in the middle of the height direction of the two sides (with rotational freedom), and the side of one side of the injection port can be matched with a pull rod or other driving mechanism commonly used in the existing industry to drive the primary air injection port to swing up and down by 15°.

[0031] As shown in Figure 3 The ammonia gas channel 2 includes an ammonia gas connecting pipeline 201 and an ammonia gas distribution box 202, and the input end of the ammonia gas channel 2 is connected with a connecting pipe head 7. The supplied ammonia gas is connected to the connecting pipe head 7 through an ammonia gas conveying metal hose flange to uniformly enter the ammonia gas distribution box 202, and then the ammonia gas flowing out of the ammonia gas distribution box 202 is transmitted by six parallel ammonia gas connecting pipelines 201, and the ammonia gas jet is injected into the furnace through the ammonia gas backflow injection head 3 at the output end (furnace end) of the ammonia gas channel 2, and the ammonia gas is forced to enter the high-temperature oxygen-free combustion area in the reverse direction.

[0032] The ammonia gas backflow injection head 3 is attached to the right side of the burner channel 4, which sprays ammonia gas in the opposite direction of the flame combustion in the furnace. The injection direction of the injection head is at an angle of 15°-25° with the central axis of the entire straight-flow burner, and the angle of the ammonia gas entering the furnace in the reverse direction is greater than the deflection angle of the dense phase primary air. The ammonia gas is supplied by a high-pressure gas source to ensure that the ammonia gas is injected at a high flow rate and enters the high-temperature oxygen-deficient area formed in the later stage of the combustion of the pulverized coal jet of the straight-flow burner in the upstream of the furnace. In order to control NOx emissions, the peripheral air injection port 101 at the dense and dilute primary air injection port 1 on one side of the ammonia gas backflow injection head 3 is closed to form a C-shaped or U-shaped structure, and no peripheral air is injected.

[0033] The burner channel 4 is the channel for the pulverized coal and the primary air, and contains a pulverized coal dense and dilute separator 6, which can separate the pulverized coal gas flow into a dense phase primary air pulverized coal gas flow and a dilute phase primary air pulverized coal gas flow along the horizontal direction of the axis.

[0034] The coal powder concentration and dilution separator 6 comprises an impact block 601 for coal powder concentration and a partition plate 602 for coal powder concentration and dilution airflow separation. The impact block 601 is located in the burner channel 4 near the connecting part 5, and the windward surface thereof is provided as an inclined surface. By impacting the inclined surface of the impact block 601 by the primary air flow, the inertia difference between the coal powder and the airflow is utilized to make the coal powder rebound after impacting the inclined surface, separate from the airflow conveying the same, and enter the airflow far away (the airflow on the side of the primary air back-blowing nozzle 102 of the dense phase) to form the dense phase primary air, so that the primary air and the coal powder conveyed thereby are separated into a dense phase coal powder airflow with larger particles and a dilute phase coal powder airflow. The partition plate 602 is located at the rear end outlet section of the burner channel 4 and is connected with the partition body 104 at the concentration and dilution primary air nozzle 1 (located at the front end of the partition body 104 and connected to the thin end of the wedge-shaped portion), to ensure that the two airflows are separated and enter the dense phase primary air back-blowing nozzle 102 and the dilute phase primary air nozzle 103, respectively. The partition plate 602 is specifically composed of a horizontal plate and an inclined plate, wherein the horizontal plate is directly connected with the partition body 104, and the inclined plate is connected to the other end of the horizontal plate. The inclined plate is provided in an inclined manner toward the flow channel on the side of the dense phase primary air back-blowing nozzle 102, so that the dilute phase coal powder airflow after separation by the impact block 601 can enter the dilute phase primary air nozzle 103. Specifically, the horizontal plate is equally divided and arranged inside the burner channel 4 (the concentration and dilution primary air channel has the same width), and the end of the inclined plate extends into the dense phase primary air channel and reaches 2 / 5 of the entire width of the burner channel 4.

[0035] As Figure 4 shown, it is the combustion state of the combustion system adopting the direct-flow burner. For the convenience of expression and display, only the state in the hearth is described. The hearth in the combustion system is a four-corner tangential combustion mode, and therefore, one of the above direct-flow burners is arranged at each of the four corners of the hearth. The dilute phase primary air coal powder jet 10 ejected from the dilute phase primary air nozzle 103 flows in the airflow direction, while the back-blowing dense phase primary air coal powder jet 20 ejected from the back-blowing dense phase primary air nozzle 102 and the back-blowing ammonia gas jet 30 ejected from the ammonia gas back-blowing nozzle 3 both enter the central high-temperature region of the hearth in the form of back-blowing counterflow, and the back-blowing angle of the back-blowing ammonia gas jet 30 is relatively larger than that of the back-blowing dense phase primary air coal powder jet 20, and it enters the high-temperature oxygen-deficient region.

[0036] The present application ensures the independence of each jet to be sprayed into the furnace by the wedge-shaped partition blunt body partitioning the primary air into dilute phase primary air and dense phase primary air, and the independent ammonia gas passage 2 and ammonia gas back flushing nozzle 3. Among them, the dense phase primary air with high pulverized coal concentration can penetrate into the main rotary cutting circle fire ring under the action of back flushing, penetrate into the high temperature area in the center of the furnace, and burn away from the wall, effectively preventing wall slagging and high temperature corrosion. The design of the ammonia gas injection direction with large angle back flushing and the form of high flow rate injection into the furnace, strengthens the mixing of ammonia gas large angle reverse jet into the furnace with the high temperature fire ring of the tail of the primary air jet of the upstream direct flow burner, and with the backflow high temperature flue gas, promotes the thermal cracking of ammonia gas into hydrogen gas, and inhibits the generation of NOx in the combustion mode of hydrogen gas, realizes the efficient mixing combustion of a large proportion of ammonia gas and coal powder. In addition, the nozzle adjusting mechanism can also realize stable combustion by adjusting the flame center height according to different working conditions.

[0037] Therefore, the present application realizes the concentration of primary air pulverized coal by the pulverized coal concentration and dilution separator 6, and then the concentration of the dense primary air is greatly improved, and through the back flushing, most of the coal particles can stay in the high temperature area for a significantly longer time during the process of leaving the nozzle and flowing and turning to the furnace, thereby greatly improving the stability of coal combustion. Therefore, the present application has the characteristics of high stability of pulverized coal combustion and zero carbon of ammonia fuel, realizes the effective control of NOx emission without obvious increase when ammonia combustion is converted to hydrogen combustion, has good combustion organization ability and environmental protection performance.

[0038] The above description of the embodiments is for the purpose of facilitating the understanding and use of the present application by those skilled in the art. Those skilled in the art can easily make various modifications to the embodiments, and apply the general principles described herein to other embodiments without creative labor. Therefore, the present application is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art according to the disclosure of the present application without departing from the scope of the present application should be within the protection scope of the present application.

Claims

1. A straight-flow burner for pulverized coal with separation of fine and coarse particles and large-angle ammonia jet back-blowing, characterized in that, It comprises an ammonia channel (2), a burner channel (4) and a pulverized coal concentration and dilution separator (6); The pulverized coal concentration and dilution separator (6) is arranged in the burner channel (4) and realizes concentration and dilution separation of the primary air by using the inertia difference between the pulverized coal and airflow in the primary air; The output end of the burner channel (4) is a concentration and dilution primary air nozzle (1), a partition body (104) is arranged in the middle of the concentration and dilution primary air nozzle (1), so that the concentration and dilution primary air nozzle (1) is divided into a concentrated primary air back-blowing nozzle (102) and a dilute primary air nozzle (103) which are not connected with each other, and the concentrated primary air back-blowing nozzle (102) and the dilute primary air nozzle (103) are used to respectively spray the concentrated primary air and the dilute primary air which are separated by concentration and dilution; an angle is arranged between the axis of the concentrated primary air back-blowing nozzle (102) and the axis of the burner channel (4), so that the concentrated primary air back-blowing nozzle (102) is arranged towards the upstream direction of the flame, and the concentrated primary air is controlled to enter the high-temperature area in the center of the furnace; The ammonia channel (2) is arranged at the side of the burner channel (4), and the ammonia channel (2) is arranged at the side close to the concentrated primary air back-blowing nozzle (102); the output end of the ammonia channel (2) is an ammonia back-blowing nozzle (3), and an angle is arranged between the ammonia back-blowing nozzle (3) and the axis of the burner channel (4), so that the ammonia back-blowing nozzle (3) is arranged towards the upstream direction of the flame, and the ammonia is controlled to enter the high-temperature and oxygen-deficient area in the furnace; The angle between the ammonia back-blowing nozzle (3) and the axis of the burner channel (4) is greater than the angle between the concentrated primary air back-blowing nozzle (102) and the axis of the burner channel (4).

2. The straight-flow combustor with coal powder concentration separation and ammonia jet large-angle backblowing according to claim 1, characterized in that, The pulverized coal concentration and dilution separator (6) comprises an impact block (601) and a partition plate (602); The impact block (601) is arranged at the position close to the input end in the burner channel (4), and the impact block (601) is arranged on the side wall at the side of the dilute primary air nozzle (103); the impact block (601) is arranged as an inclined surface at the airflow side; The partition plate (602) is arranged at the position close to the output end in the burner channel (4), and the partition plate (602) is connected to one end of the partition body (104).

3. The straight-flow burner of claim 1, wherein, The input end of the burner channel (4) is provided with a connecting component (5), and the connecting component (5) comprises a connecting channel (501) and a connecting flange (502); One end of the connecting channel (501) is connected with the burner channel (4); The connecting flange (502) is connected with the other end of the connecting channel (501).

4. The straight-flow burner of claim 1, wherein, The concentration and dilution primary air nozzle (1) further comprises a perimeter air nozzle (101); The perimeter air nozzle (101) is arranged around the edge of the concentration and dilution primary air nozzle (1), and the perimeter air nozzle (101) is not opened at the side close to the ammonia back-blowing nozzle (3), forming a U-shaped or C-shaped structure.

5. The straight-flow burner of claim 1, wherein, The first nozzle side wall (106) which is parallel to the partition body (104) in the concentrated primary air back-blowing nozzle (102) is an inclined surface, and the first nozzle side wall (106) is arranged towards the direction away from the axis of the burner channel (4); The second side wall (105) of the dilute phase primary air nozzle (103) is parallel to the partition body (104) and is a plane. The partition body (104) is a wedge-shaped partition body, and the surface of the partition body (104) on one side of the dense phase primary air back-blowing nozzle (102) is a plane and is parallel to the first side wall (106) of the nozzle.

6. The straight-flow burner of claim 1, wherein, The axis of the dense phase primary air back-blowing nozzle (102) and the axis of the combustor passage (4) form an included angle of 10-20°.

7. The direct flow burner of claim 1, wherein, The ammonia gas passage (2) comprises ammonia gas connecting pipes (201) and an ammonia gas distribution box (202). The ammonia gas distribution box (202) is connected to the ammonia gas back-blowing nozzles (3) through the ammonia gas connecting pipes (201).

8. The direct flow burner of claim 1, wherein, The input end of the ammonia gas passage (2) is provided with a connecting pipe head (7).

9. The direct flow burner of claim 1, wherein, The thick and thin primary air nozzle (1) is movably connected to the combustor passage (4) through a nozzle adjusting device, which is used for adjusting the height of the primary air ejected from the thick and thin primary air nozzle (1).

10. A pulverized coal combustion system with dense and dilute phase separation and ammonia jet large angle back blowing, characterized in that, The direct-flow combustor according to any one of claims 1-9 is arranged at four corners of the hearth to form a four-corner tangential combustion mode. The dense phase primary air penetrates into the main rotating tangential flame ring and reaches the high-temperature area in the center of the hearth to burn away from the wall under the action of back blowing. After the ammonia gas is injected into the hearth, the ammonia gas is mixed with the high-temperature flue gas in the tail of the primary air jet of the upstream direct-flow combustor and with the backflowing high-temperature flue gas. ​

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